/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp

Bug Summary

File:	llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
Warning:	line 2497, column 23 2nd function call argument is an uninitialized value
Annotated Source Code

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1//===- MemorySanitizer.cpp - detector of uninitialized reads --------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9/// \file
10/// This file is a part of MemorySanitizer, a detector of uninitialized
11/// reads.
12///
13/// The algorithm of the tool is similar to Memcheck
14/// (http://goo.gl/QKbem). We associate a few shadow bits with every
15/// byte of the application memory, poison the shadow of the malloc-ed
16/// or alloca-ed memory, load the shadow bits on every memory read,
17/// propagate the shadow bits through some of the arithmetic
18/// instruction (including MOV), store the shadow bits on every memory
19/// write, report a bug on some other instructions (e.g. JMP) if the
20/// associated shadow is poisoned.
21///
22/// But there are differences too. The first and the major one:
23/// compiler instrumentation instead of binary instrumentation. This
24/// gives us much better register allocation, possible compiler
25/// optimizations and a fast start-up. But this brings the major issue
26/// as well: msan needs to see all program events, including system
27/// calls and reads/writes in system libraries, so we either need to
28/// compile *everything* with msan or use a binary translation
29/// component (e.g. DynamoRIO) to instrument pre-built libraries.
30/// Another difference from Memcheck is that we use 8 shadow bits per
31/// byte of application memory and use a direct shadow mapping. This
32/// greatly simplifies the instrumentation code and avoids races on
33/// shadow updates (Memcheck is single-threaded so races are not a
34/// concern there. Memcheck uses 2 shadow bits per byte with a slow
35/// path storage that uses 8 bits per byte).
36///
37/// The default value of shadow is 0, which means "clean" (not poisoned).
38///
39/// Every module initializer should call __msan_init to ensure that the
40/// shadow memory is ready. On error, __msan_warning is called. Since
41/// parameters and return values may be passed via registers, we have a
42/// specialized thread-local shadow for return values
43/// (__msan_retval_tls) and parameters (__msan_param_tls).
44///
45///                           Origin tracking.
46///
47/// MemorySanitizer can track origins (allocation points) of all uninitialized
48/// values. This behavior is controlled with a flag (msan-track-origins) and is
49/// disabled by default.
50///
51/// Origins are 4-byte values created and interpreted by the runtime library.
52/// They are stored in a second shadow mapping, one 4-byte value for 4 bytes
53/// of application memory. Propagation of origins is basically a bunch of
54/// "select" instructions that pick the origin of a dirty argument, if an
55/// instruction has one.
56///
57/// Every 4 aligned, consecutive bytes of application memory have one origin
58/// value associated with them. If these bytes contain uninitialized data
59/// coming from 2 different allocations, the last store wins. Because of this,
60/// MemorySanitizer reports can show unrelated origins, but this is unlikely in
61/// practice.
62///
63/// Origins are meaningless for fully initialized values, so MemorySanitizer
64/// avoids storing origin to memory when a fully initialized value is stored.
65/// This way it avoids needless overwritting origin of the 4-byte region on
66/// a short (i.e. 1 byte) clean store, and it is also good for performance.
67///
68///                            Atomic handling.
69///
70/// Ideally, every atomic store of application value should update the
71/// corresponding shadow location in an atomic way. Unfortunately, atomic store
72/// of two disjoint locations can not be done without severe slowdown.
73///
74/// Therefore, we implement an approximation that may err on the safe side.
75/// In this implementation, every atomically accessed location in the program
76/// may only change from (partially) uninitialized to fully initialized, but
77/// not the other way around. We load the shadow _after_ the application load,
78/// and we store the shadow _before_ the app store. Also, we always store clean
79/// shadow (if the application store is atomic). This way, if the store-load
80/// pair constitutes a happens-before arc, shadow store and load are correctly
81/// ordered such that the load will get either the value that was stored, or
82/// some later value (which is always clean).
83///
84/// This does not work very well with Compare-And-Swap (CAS) and
85/// Read-Modify-Write (RMW) operations. To follow the above logic, CAS and RMW
86/// must store the new shadow before the app operation, and load the shadow
87/// after the app operation. Computers don't work this way. Current
88/// implementation ignores the load aspect of CAS/RMW, always returning a clean
89/// value. It implements the store part as a simple atomic store by storing a
90/// clean shadow.
91///
92///                      Instrumenting inline assembly.
93///
94/// For inline assembly code LLVM has little idea about which memory locations
95/// become initialized depending on the arguments. It can be possible to figure
96/// out which arguments are meant to point to inputs and outputs, but the
97/// actual semantics can be only visible at runtime. In the Linux kernel it's
98/// also possible that the arguments only indicate the offset for a base taken
99/// from a segment register, so it's dangerous to treat any asm() arguments as
100/// pointers. We take a conservative approach generating calls to
101///   __msan_instrument_asm_store(ptr, size)
102/// , which defer the memory unpoisoning to the runtime library.
103/// The latter can perform more complex address checks to figure out whether
104/// it's safe to touch the shadow memory.
105/// Like with atomic operations, we call __msan_instrument_asm_store() before
106/// the assembly call, so that changes to the shadow memory will be seen by
107/// other threads together with main memory initialization.
108///
109///                  KernelMemorySanitizer (KMSAN) implementation.
110///
111/// The major differences between KMSAN and MSan instrumentation are:
112///  - KMSAN always tracks the origins and implies msan-keep-going=true;
113///  - KMSAN allocates shadow and origin memory for each page separately, so
114///    there are no explicit accesses to shadow and origin in the
115///    instrumentation.
116///    Shadow and origin values for a particular X-byte memory location
117///    (X=1,2,4,8) are accessed through pointers obtained via the
118///      __msan_metadata_ptr_for_load_X(ptr)
119///      __msan_metadata_ptr_for_store_X(ptr)
120///    functions. The corresponding functions check that the X-byte accesses
121///    are possible and returns the pointers to shadow and origin memory.
122///    Arbitrary sized accesses are handled with:
123///      __msan_metadata_ptr_for_load_n(ptr, size)
124///      __msan_metadata_ptr_for_store_n(ptr, size);
125///  - TLS variables are stored in a single per-task struct. A call to a
126///    function __msan_get_context_state() returning a pointer to that struct
127///    is inserted into every instrumented function before the entry block;
128///  - __msan_warning() takes a 32-bit origin parameter;
129///  - local variables are poisoned with __msan_poison_alloca() upon function
130///    entry and unpoisoned with __msan_unpoison_alloca() before leaving the
131///    function;
132///  - the pass doesn't declare any global variables or add global constructors
133///    to the translation unit.
134///
135/// Also, KMSAN currently ignores uninitialized memory passed into inline asm
136/// calls, making sure we're on the safe side wrt. possible false positives.
137///
138///  KernelMemorySanitizer only supports X86_64 at the moment.
139///
140//===----------------------------------------------------------------------===//

142#include "llvm/Transforms/Instrumentation/MemorySanitizer.h"
143#include "llvm/ADT/APInt.h"
144#include "llvm/ADT/ArrayRef.h"
145#include "llvm/ADT/DepthFirstIterator.h"
146#include "llvm/ADT/SmallSet.h"
147#include "llvm/ADT/SmallString.h"
148#include "llvm/ADT/SmallVector.h"
149#include "llvm/ADT/StringExtras.h"
150#include "llvm/ADT/StringRef.h"
151#include "llvm/ADT/Triple.h"
152#include "llvm/Analysis/TargetLibraryInfo.h"
153#include "llvm/IR/Argument.h"
154#include "llvm/IR/Attributes.h"
155#include "llvm/IR/BasicBlock.h"
156#include "llvm/IR/CallSite.h"
157#include "llvm/IR/CallingConv.h"
158#include "llvm/IR/Constant.h"
159#include "llvm/IR/Constants.h"
160#include "llvm/IR/DataLayout.h"
161#include "llvm/IR/DerivedTypes.h"
162#include "llvm/IR/Function.h"
163#include "llvm/IR/GlobalValue.h"
164#include "llvm/IR/GlobalVariable.h"
165#include "llvm/IR/IRBuilder.h"
166#include "llvm/IR/InlineAsm.h"
167#include "llvm/IR/InstVisitor.h"
168#include "llvm/IR/InstrTypes.h"
169#include "llvm/IR/Instruction.h"
170#include "llvm/IR/Instructions.h"
171#include "llvm/IR/IntrinsicInst.h"
172#include "llvm/IR/Intrinsics.h"
173#include "llvm/IR/IntrinsicsX86.h"
174#include "llvm/IR/LLVMContext.h"
175#include "llvm/IR/MDBuilder.h"
176#include "llvm/IR/Module.h"
177#include "llvm/IR/Type.h"
178#include "llvm/IR/Value.h"
179#include "llvm/IR/ValueMap.h"
180#include "llvm/InitializePasses.h"
181#include "llvm/Pass.h"
182#include "llvm/Support/AtomicOrdering.h"
183#include "llvm/Support/Casting.h"
184#include "llvm/Support/CommandLine.h"
185#include "llvm/Support/Compiler.h"
186#include "llvm/Support/Debug.h"
187#include "llvm/Support/ErrorHandling.h"
188#include "llvm/Support/MathExtras.h"
189#include "llvm/Support/raw_ostream.h"
190#include "llvm/Transforms/Instrumentation.h"
191#include "llvm/Transforms/Utils/BasicBlockUtils.h"
192#include "llvm/Transforms/Utils/Local.h"
193#include "llvm/Transforms/Utils/ModuleUtils.h"
194#include <algorithm>
195#include <cassert>
196#include <cstddef>
197#include <cstdint>
198#include <memory>
199#include <string>
200#include <tuple>

202using namespace llvm;

204#define DEBUG_TYPE"msan" "msan"

206static const unsigned kOriginSize = 4;
207static const Align kMinOriginAlignment = Align(4);
208static const Align kShadowTLSAlignment = Align(8);

210// These constants must be kept in sync with the ones in msan.h.
211static const unsigned kParamTLSSize = 800;
212static const unsigned kRetvalTLSSize = 800;

214// Accesses sizes are powers of two: 1, 2, 4, 8.
215static const size_t kNumberOfAccessSizes = 4;

217/// Track origins of uninitialized values.
218///
219/// Adds a section to MemorySanitizer report that points to the allocation
220/// (stack or heap) the uninitialized bits came from originally.
221static cl::opt<int> ClTrackOrigins("msan-track-origins",
     cl::desc("Track origins (allocation sites) of poisoned memory"),
     cl::Hidden, cl::init(0));

225static cl::opt<bool> ClKeepGoing("msan-keep-going",
     cl::desc("keep going after reporting a UMR"),
     cl::Hidden, cl::init(false));

229static cl::opt<bool> ClPoisonStack("msan-poison-stack",
     cl::desc("poison uninitialized stack variables"),
     cl::Hidden, cl::init(true));

233static cl::opt<bool> ClPoisonStackWithCall("msan-poison-stack-with-call",
     cl::desc("poison uninitialized stack variables with a call"),
     cl::Hidden, cl::init(false));

237static cl::opt<int> ClPoisonStackPattern("msan-poison-stack-pattern",
     cl::desc("poison uninitialized stack variables with the given pattern"),
     cl::Hidden, cl::init(0xff));

241static cl::opt<bool> ClPoisonUndef("msan-poison-undef",
     cl::desc("poison undef temps"),
     cl::Hidden, cl::init(true));

245static cl::opt<bool> ClHandleICmp("msan-handle-icmp",
     cl::desc("propagate shadow through ICmpEQ and ICmpNE"),
     cl::Hidden, cl::init(true));

249static cl::opt<bool> ClHandleICmpExact("msan-handle-icmp-exact",
     cl::desc("exact handling of relational integer ICmp"),
     cl::Hidden, cl::init(false));

253static cl::opt<bool> ClHandleLifetimeIntrinsics(
  "msan-handle-lifetime-intrinsics",
  cl::desc(
      "when possible, poison scoped variables at the beginning of the scope "
      "(slower, but more precise)"),
  cl::Hidden, cl::init(true));

260// When compiling the Linux kernel, we sometimes see false positives related to
261// MSan being unable to understand that inline assembly calls may initialize
262// local variables.
263// This flag makes the compiler conservatively unpoison every memory location
264// passed into an assembly call. Note that this may cause false positives.
265// Because it's impossible to figure out the array sizes, we can only unpoison
266// the first sizeof(type) bytes for each type* pointer.
267// The instrumentation is only enabled in KMSAN builds, and only if
268// -msan-handle-asm-conservative is on. This is done because we may want to
269// quickly disable assembly instrumentation when it breaks.
270static cl::opt<bool> ClHandleAsmConservative(
  "msan-handle-asm-conservative",
  cl::desc("conservative handling of inline assembly"), cl::Hidden,
  cl::init(true));

275// This flag controls whether we check the shadow of the address
276// operand of load or store. Such bugs are very rare, since load from
277// a garbage address typically results in SEGV, but still happen
278// (e.g. only lower bits of address are garbage, or the access happens
279// early at program startup where malloc-ed memory is more likely to
280// be zeroed. As of 2012-08-28 this flag adds 20% slowdown.
281static cl::opt<bool> ClCheckAccessAddress("msan-check-access-address",
     cl::desc("report accesses through a pointer which has poisoned shadow"),
     cl::Hidden, cl::init(true));

285static cl::opt<bool> ClDumpStrictInstructions("msan-dump-strict-instructions",
     cl::desc("print out instructions with default strict semantics"),
     cl::Hidden, cl::init(false));

289static cl::opt<int> ClInstrumentationWithCallThreshold(
  "msan-instrumentation-with-call-threshold",
  cl::desc(
      "If the function being instrumented requires more than "
      "this number of checks and origin stores, use callbacks instead of "
      "inline checks (-1 means never use callbacks)."),
  cl::Hidden, cl::init(3500));

297static cl::opt<bool>
  ClEnableKmsan("msan-kernel",
                cl::desc("Enable KernelMemorySanitizer instrumentation"),
                cl::Hidden, cl::init(false));

302// This is an experiment to enable handling of cases where shadow is a non-zero
303// compile-time constant. For some unexplainable reason they were silently
304// ignored in the instrumentation.
305static cl::opt<bool> ClCheckConstantShadow("msan-check-constant-shadow",
     cl::desc("Insert checks for constant shadow values"),
     cl::Hidden, cl::init(false));

309// This is off by default because of a bug in gold:
310// https://sourceware.org/bugzilla/show_bug.cgi?id=19002
311static cl::opt<bool> ClWithComdat("msan-with-comdat",
     cl::desc("Place MSan constructors in comdat sections"),
     cl::Hidden, cl::init(false));

315// These options allow to specify custom memory map parameters
316// See MemoryMapParams for details.
317static cl::opt<uint64_t> ClAndMask("msan-and-mask",
                                 cl::desc("Define custom MSan AndMask"),
                                 cl::Hidden, cl::init(0));

321static cl::opt<uint64_t> ClXorMask("msan-xor-mask",
                                 cl::desc("Define custom MSan XorMask"),
                                 cl::Hidden, cl::init(0));

325static cl::opt<uint64_t> ClShadowBase("msan-shadow-base",
                                    cl::desc("Define custom MSan ShadowBase"),
                                    cl::Hidden, cl::init(0));

329static cl::opt<uint64_t> ClOriginBase("msan-origin-base",
                                    cl::desc("Define custom MSan OriginBase"),
                                    cl::Hidden, cl::init(0));

333static const char *const kMsanModuleCtorName = "msan.module_ctor";
334static const char *const kMsanInitName = "__msan_init";

336namespace {

338// Memory map parameters used in application-to-shadow address calculation.
339// Offset = (Addr & ~AndMask) ^ XorMask
340// Shadow = ShadowBase + Offset
341// Origin = OriginBase + Offset
342struct MemoryMapParams {
uint64_t AndMask;
uint64_t XorMask;
uint64_t ShadowBase;
uint64_t OriginBase;
347};

349struct PlatformMemoryMapParams {
const MemoryMapParams *bits32;
const MemoryMapParams *bits64;
352};

354} // end anonymous namespace

356// i386 Linux
357static const MemoryMapParams Linux_I386_MemoryMapParams = {
0x000080000000,  // AndMask
0,               // XorMask (not used)
0,               // ShadowBase (not used)
0x000040000000,  // OriginBase
362};

364// x86_64 Linux
365static const MemoryMapParams Linux_X86_64_MemoryMapParams = {
366#ifdef MSAN_LINUX_X86_64_OLD_MAPPING
0x400000000000,  // AndMask
0,               // XorMask (not used)
0,               // ShadowBase (not used)
0x200000000000,  // OriginBase
371#else
0,               // AndMask (not used)
0x500000000000,  // XorMask
0,               // ShadowBase (not used)
0x100000000000,  // OriginBase
376#endif
377};

379// mips64 Linux
380static const MemoryMapParams Linux_MIPS64_MemoryMapParams = {
0,               // AndMask (not used)
0x008000000000,  // XorMask
0,               // ShadowBase (not used)
0x002000000000,  // OriginBase
385};

387// ppc64 Linux
388static const MemoryMapParams Linux_PowerPC64_MemoryMapParams = {
0xE00000000000,  // AndMask
0x100000000000,  // XorMask
0x080000000000,  // ShadowBase
0x1C0000000000,  // OriginBase
393};

395// aarch64 Linux
396static const MemoryMapParams Linux_AArch64_MemoryMapParams = {
0,               // AndMask (not used)
0x06000000000,   // XorMask
0,               // ShadowBase (not used)
0x01000000000,   // OriginBase
401};

403// i386 FreeBSD
404static const MemoryMapParams FreeBSD_I386_MemoryMapParams = {
0x000180000000,  // AndMask
0x000040000000,  // XorMask
0x000020000000,  // ShadowBase
0x000700000000,  // OriginBase
409};

411// x86_64 FreeBSD
412static const MemoryMapParams FreeBSD_X86_64_MemoryMapParams = {
0xc00000000000,  // AndMask
0x200000000000,  // XorMask
0x100000000000,  // ShadowBase
0x380000000000,  // OriginBase
417};

419// x86_64 NetBSD
420static const MemoryMapParams NetBSD_X86_64_MemoryMapParams = {
0,               // AndMask
0x500000000000,  // XorMask
0,               // ShadowBase
0x100000000000,  // OriginBase
425};

427static const PlatformMemoryMapParams Linux_X86_MemoryMapParams = {
&Linux_I386_MemoryMapParams,
&Linux_X86_64_MemoryMapParams,
430};

432static const PlatformMemoryMapParams Linux_MIPS_MemoryMapParams = {
nullptr,
&Linux_MIPS64_MemoryMapParams,
435};

437static const PlatformMemoryMapParams Linux_PowerPC_MemoryMapParams = {
nullptr,
&Linux_PowerPC64_MemoryMapParams,
440};

442static const PlatformMemoryMapParams Linux_ARM_MemoryMapParams = {
nullptr,
&Linux_AArch64_MemoryMapParams,
445};

447static const PlatformMemoryMapParams FreeBSD_X86_MemoryMapParams = {
&FreeBSD_I386_MemoryMapParams,
&FreeBSD_X86_64_MemoryMapParams,
450};

452static const PlatformMemoryMapParams NetBSD_X86_MemoryMapParams = {
nullptr,
&NetBSD_X86_64_MemoryMapParams,
455};

457namespace {

459/// Instrument functions of a module to detect uninitialized reads.
460///
461/// Instantiating MemorySanitizer inserts the msan runtime library API function
462/// declarations into the module if they don't exist already. Instantiating
463/// ensures the __msan_init function is in the list of global constructors for
464/// the module.
465class MemorySanitizer {
466public:
MemorySanitizer(Module &M, MemorySanitizerOptions Options)
    : CompileKernel(Options.Kernel), TrackOrigins(Options.TrackOrigins),
      Recover(Options.Recover) {
  initializeModule(M);
}

// MSan cannot be moved or copied because of MapParams.
MemorySanitizer(MemorySanitizer &&) = delete;
MemorySanitizer &operator=(MemorySanitizer &&) = delete;
MemorySanitizer(const MemorySanitizer &) = delete;
MemorySanitizer &operator=(const MemorySanitizer &) = delete;

bool sanitizeFunction(Function &F, TargetLibraryInfo &TLI);

481private:
friend struct MemorySanitizerVisitor;
friend struct VarArgAMD64Helper;
friend struct VarArgMIPS64Helper;
friend struct VarArgAArch64Helper;
friend struct VarArgPowerPC64Helper;

void initializeModule(Module &M);
void initializeCallbacks(Module &M);
void createKernelApi(Module &M);
void createUserspaceApi(Module &M);

/// True if we're compiling the Linux kernel.
bool CompileKernel;
/// Track origins (allocation points) of uninitialized values.
int TrackOrigins;
bool Recover;

LLVMContext *C;
Type *IntptrTy;
Type *OriginTy;

// XxxTLS variables represent the per-thread state in MSan and per-task state
// in KMSAN.
// For the userspace these point to thread-local globals. In the kernel land
// they point to the members of a per-task struct obtained via a call to
// __msan_get_context_state().

/// Thread-local shadow storage for function parameters.
Value *ParamTLS;

/// Thread-local origin storage for function parameters.
Value *ParamOriginTLS;

/// Thread-local shadow storage for function return value.
Value *RetvalTLS;

/// Thread-local origin storage for function return value.
Value *RetvalOriginTLS;

/// Thread-local shadow storage for in-register va_arg function
/// parameters (x86_64-specific).
Value *VAArgTLS;

/// Thread-local shadow storage for in-register va_arg function
/// parameters (x86_64-specific).
Value *VAArgOriginTLS;

/// Thread-local shadow storage for va_arg overflow area
/// (x86_64-specific).
Value *VAArgOverflowSizeTLS;

/// Thread-local space used to pass origin value to the UMR reporting
/// function.
Value *OriginTLS;

/// Are the instrumentation callbacks set up?
bool CallbacksInitialized = false;

/// The run-time callback to print a warning.
FunctionCallee WarningFn;

// These arrays are indexed by log2(AccessSize).
FunctionCallee MaybeWarningFn[kNumberOfAccessSizes];
FunctionCallee MaybeStoreOriginFn[kNumberOfAccessSizes];

/// Run-time helper that generates a new origin value for a stack
/// allocation.
FunctionCallee MsanSetAllocaOrigin4Fn;

/// Run-time helper that poisons stack on function entry.
FunctionCallee MsanPoisonStackFn;

/// Run-time helper that records a store (or any event) of an
/// uninitialized value and returns an updated origin id encoding this info.
FunctionCallee MsanChainOriginFn;

/// MSan runtime replacements for memmove, memcpy and memset.
FunctionCallee MemmoveFn, MemcpyFn, MemsetFn;

/// KMSAN callback for task-local function argument shadow.
StructType *MsanContextStateTy;
FunctionCallee MsanGetContextStateFn;

/// Functions for poisoning/unpoisoning local variables
FunctionCallee MsanPoisonAllocaFn, MsanUnpoisonAllocaFn;

/// Each of the MsanMetadataPtrXxx functions returns a pair of shadow/origin
/// pointers.
FunctionCallee MsanMetadataPtrForLoadN, MsanMetadataPtrForStoreN;
FunctionCallee MsanMetadataPtrForLoad_1_8[4];
FunctionCallee MsanMetadataPtrForStore_1_8[4];
FunctionCallee MsanInstrumentAsmStoreFn;

/// Helper to choose between different MsanMetadataPtrXxx().
FunctionCallee getKmsanShadowOriginAccessFn(bool isStore, int size);

/// Memory map parameters used in application-to-shadow calculation.
const MemoryMapParams *MapParams;

/// Custom memory map parameters used when -msan-shadow-base or
// -msan-origin-base is provided.
MemoryMapParams CustomMapParams;

MDNode *ColdCallWeights;

/// Branch weights for origin store.
MDNode *OriginStoreWeights;

/// An empty volatile inline asm that prevents callback merge.
InlineAsm *EmptyAsm;
592};

594void insertModuleCtor(Module &M) {
getOrCreateSanitizerCtorAndInitFunctions(
    M, kMsanModuleCtorName, kMsanInitName,
    /*InitArgTypes=*/{},
    /*InitArgs=*/{},
    // This callback is invoked when the functions are created the first
    // time. Hook them into the global ctors list in that case:
    [&](Function *Ctor, FunctionCallee) {
      if (!ClWithComdat) {
        appendToGlobalCtors(M, Ctor, 0);
        return;
      }
      Comdat *MsanCtorComdat = M.getOrInsertComdat(kMsanModuleCtorName);
      Ctor->setComdat(MsanCtorComdat);
      appendToGlobalCtors(M, Ctor, 0, Ctor);
    });
610}

612/// A legacy function pass for msan instrumentation.
613///
614/// Instruments functions to detect unitialized reads.
615struct MemorySanitizerLegacyPass : public FunctionPass {
// Pass identification, replacement for typeid.
static char ID;

MemorySanitizerLegacyPass(MemorySanitizerOptions Options = {})
    : FunctionPass(ID), Options(Options) {}
StringRef getPassName() const override { return "MemorySanitizerLegacyPass"; }

void getAnalysisUsage(AnalysisUsage &AU) const override {
  AU.addRequired<TargetLibraryInfoWrapperPass>();
}

bool runOnFunction(Function &F) override {
  return MSan->sanitizeFunction(
      F, getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F));
}
bool doInitialization(Module &M) override;

Optional<MemorySanitizer> MSan;
MemorySanitizerOptions Options;
635};

637template <class T> T getOptOrDefault(const cl::opt<T> &Opt, T Default) {
return (Opt.getNumOccurrences() > 0) ? Opt : Default;
639}

641} // end anonymous namespace

643MemorySanitizerOptions::MemorySanitizerOptions(int TO, bool R, bool K)
  : Kernel(getOptOrDefault(ClEnableKmsan, K)),
    TrackOrigins(getOptOrDefault(ClTrackOrigins, Kernel ? 2 : TO)),
    Recover(getOptOrDefault(ClKeepGoing, Kernel || R)) {}

648PreservedAnalyses MemorySanitizerPass::run(Function &F,
                                         FunctionAnalysisManager &FAM) {
MemorySanitizer Msan(*F.getParent(), Options);
if (Msan.sanitizeFunction(F, FAM.getResult<TargetLibraryAnalysis>(F)))
  return PreservedAnalyses::none();
return PreservedAnalyses::all();
654}

656PreservedAnalyses MemorySanitizerPass::run(Module &M,
                                         ModuleAnalysisManager &AM) {
if (Options.Kernel)
  return PreservedAnalyses::all();
insertModuleCtor(M);
return PreservedAnalyses::none();
662}

664char MemorySanitizerLegacyPass::ID = 0;

666INITIALIZE_PASS_BEGIN(MemorySanitizerLegacyPass, "msan",static void *initializeMemorySanitizerLegacyPassPassOnce(PassRegistry
 &Registry) {
                    "MemorySanitizer: detects uninitialized reads.", false,static void *initializeMemorySanitizerLegacyPassPassOnce(PassRegistry
 &Registry) {
                    false)static void *initializeMemorySanitizerLegacyPassPassOnce(PassRegistry
 &Registry) {
669INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry);
670INITIALIZE_PASS_END(MemorySanitizerLegacyPass, "msan",PassInfo *PI = new PassInfo( "MemorySanitizer: detects uninitialized reads."
, "msan", &MemorySanitizerLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<MemorySanitizerLegacyPass>), false, false
); Registry.registerPass(*PI, true); return PI; } static llvm
::once_flag InitializeMemorySanitizerLegacyPassPassFlag; void
 llvm::initializeMemorySanitizerLegacyPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeMemorySanitizerLegacyPassPassFlag
, initializeMemorySanitizerLegacyPassPassOnce, std::ref(Registry
)); }
                  "MemorySanitizer: detects uninitialized reads.", false,PassInfo *PI = new PassInfo( "MemorySanitizer: detects uninitialized reads."
, "msan", &MemorySanitizerLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<MemorySanitizerLegacyPass>), false, false
); Registry.registerPass(*PI, true); return PI; } static llvm
::once_flag InitializeMemorySanitizerLegacyPassPassFlag; void
 llvm::initializeMemorySanitizerLegacyPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeMemorySanitizerLegacyPassPassFlag
, initializeMemorySanitizerLegacyPassPassOnce, std::ref(Registry
)); }
                  false)PassInfo *PI = new PassInfo( "MemorySanitizer: detects uninitialized reads."
, "msan", &MemorySanitizerLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<MemorySanitizerLegacyPass>), false, false
); Registry.registerPass(*PI, true); return PI; } static llvm
::once_flag InitializeMemorySanitizerLegacyPassPassFlag; void
 llvm::initializeMemorySanitizerLegacyPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeMemorySanitizerLegacyPassPassFlag
, initializeMemorySanitizerLegacyPassPassOnce, std::ref(Registry
)); }

674FunctionPass *
675llvm::createMemorySanitizerLegacyPassPass(MemorySanitizerOptions Options) {
return new MemorySanitizerLegacyPass(Options);
677}

679/// Create a non-const global initialized with the given string.
680///
681/// Creates a writable global for Str so that we can pass it to the
682/// run-time lib. Runtime uses first 4 bytes of the string to store the
683/// frame ID, so the string needs to be mutable.
684static GlobalVariable *createPrivateNonConstGlobalForString(Module &M,
                                                          StringRef Str) {
Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
return new GlobalVariable(M, StrConst->getType(), /*isConstant=*/false,
                          GlobalValue::PrivateLinkage, StrConst, "");
689}

691/// Create KMSAN API callbacks.
692void MemorySanitizer::createKernelApi(Module &M) {
IRBuilder<> IRB(*C);

// These will be initialized in insertKmsanPrologue().
RetvalTLS = nullptr;
RetvalOriginTLS = nullptr;
ParamTLS = nullptr;
ParamOriginTLS = nullptr;
VAArgTLS = nullptr;
VAArgOriginTLS = nullptr;
VAArgOverflowSizeTLS = nullptr;
// OriginTLS is unused in the kernel.
OriginTLS = nullptr;

// __msan_warning() in the kernel takes an origin.
WarningFn = M.getOrInsertFunction("__msan_warning", IRB.getVoidTy(),
                                  IRB.getInt32Ty());
// Requests the per-task context state (kmsan_context_state*) from the
// runtime library.
MsanContextStateTy = StructType::get(
    ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8),
    ArrayType::get(IRB.getInt64Ty(), kRetvalTLSSize / 8),
    ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8),
    ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8), /* va_arg_origin */
    IRB.getInt64Ty(), ArrayType::get(OriginTy, kParamTLSSize / 4), OriginTy,
    OriginTy);
MsanGetContextStateFn = M.getOrInsertFunction(
    "__msan_get_context_state", PointerType::get(MsanContextStateTy, 0));

Type *RetTy = StructType::get(PointerType::get(IRB.getInt8Ty(), 0),
                              PointerType::get(IRB.getInt32Ty(), 0));

for (int ind = 0, size = 1; ind < 4; ind++, size <<= 1) {
  std::string name_load =
      "__msan_metadata_ptr_for_load_" + std::to_string(size);
  std::string name_store =
      "__msan_metadata_ptr_for_store_" + std::to_string(size);
  MsanMetadataPtrForLoad_1_8[ind] = M.getOrInsertFunction(
      name_load, RetTy, PointerType::get(IRB.getInt8Ty(), 0));
  MsanMetadataPtrForStore_1_8[ind] = M.getOrInsertFunction(
      name_store, RetTy, PointerType::get(IRB.getInt8Ty(), 0));
}

MsanMetadataPtrForLoadN = M.getOrInsertFunction(
    "__msan_metadata_ptr_for_load_n", RetTy,
    PointerType::get(IRB.getInt8Ty(), 0), IRB.getInt64Ty());
MsanMetadataPtrForStoreN = M.getOrInsertFunction(
    "__msan_metadata_ptr_for_store_n", RetTy,
    PointerType::get(IRB.getInt8Ty(), 0), IRB.getInt64Ty());

// Functions for poisoning and unpoisoning memory.
MsanPoisonAllocaFn =
    M.getOrInsertFunction("__msan_poison_alloca", IRB.getVoidTy(),
                          IRB.getInt8PtrTy(), IntptrTy, IRB.getInt8PtrTy());
MsanUnpoisonAllocaFn = M.getOrInsertFunction(
    "__msan_unpoison_alloca", IRB.getVoidTy(), IRB.getInt8PtrTy(), IntptrTy);
748}

750static Constant *getOrInsertGlobal(Module &M, StringRef Name, Type *Ty) {
return M.getOrInsertGlobal(Name, Ty, [&] {
  return new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage,
                            nullptr, Name, nullptr,
                            GlobalVariable::InitialExecTLSModel);
});
756}

758/// Insert declarations for userspace-specific functions and globals.
759void MemorySanitizer::createUserspaceApi(Module &M) {
IRBuilder<> IRB(*C);
// Create the callback.
// FIXME: this function should have "Cold" calling conv,
// which is not yet implemented.
StringRef WarningFnName = Recover ? "__msan_warning"
                                  : "__msan_warning_noreturn";
WarningFn = M.getOrInsertFunction(WarningFnName, IRB.getVoidTy());

// Create the global TLS variables.
RetvalTLS =
    getOrInsertGlobal(M, "__msan_retval_tls",
                      ArrayType::get(IRB.getInt64Ty(), kRetvalTLSSize / 8));

RetvalOriginTLS = getOrInsertGlobal(M, "__msan_retval_origin_tls", OriginTy);

ParamTLS =
    getOrInsertGlobal(M, "__msan_param_tls",
                      ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8));

ParamOriginTLS =
    getOrInsertGlobal(M, "__msan_param_origin_tls",
                      ArrayType::get(OriginTy, kParamTLSSize / 4));

VAArgTLS =
    getOrInsertGlobal(M, "__msan_va_arg_tls",
                      ArrayType::get(IRB.getInt64Ty(), kParamTLSSize / 8));

VAArgOriginTLS =
    getOrInsertGlobal(M, "__msan_va_arg_origin_tls",
                      ArrayType::get(OriginTy, kParamTLSSize / 4));

VAArgOverflowSizeTLS =
    getOrInsertGlobal(M, "__msan_va_arg_overflow_size_tls", IRB.getInt64Ty());
OriginTLS = getOrInsertGlobal(M, "__msan_origin_tls", IRB.getInt32Ty());

for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
     AccessSizeIndex++) {
  unsigned AccessSize = 1 << AccessSizeIndex;
  std::string FunctionName = "__msan_maybe_warning_" + itostr(AccessSize);
  MaybeWarningFn[AccessSizeIndex] = M.getOrInsertFunction(
      FunctionName, IRB.getVoidTy(), IRB.getIntNTy(AccessSize * 8),
      IRB.getInt32Ty());

  FunctionName = "__msan_maybe_store_origin_" + itostr(AccessSize);
  MaybeStoreOriginFn[AccessSizeIndex] = M.getOrInsertFunction(
      FunctionName, IRB.getVoidTy(), IRB.getIntNTy(AccessSize * 8),
      IRB.getInt8PtrTy(), IRB.getInt32Ty());
}

MsanSetAllocaOrigin4Fn = M.getOrInsertFunction(
  "__msan_set_alloca_origin4", IRB.getVoidTy(), IRB.getInt8PtrTy(), IntptrTy,
  IRB.getInt8PtrTy(), IntptrTy);
MsanPoisonStackFn =
    M.getOrInsertFunction("__msan_poison_stack", IRB.getVoidTy(),
                          IRB.getInt8PtrTy(), IntptrTy);
815}

817/// Insert extern declaration of runtime-provided functions and globals.
818void MemorySanitizer::initializeCallbacks(Module &M) {
// Only do this once.
if (CallbacksInitialized)
  return;

IRBuilder<> IRB(*C);
// Initialize callbacks that are common for kernel and userspace
// instrumentation.
MsanChainOriginFn = M.getOrInsertFunction(
  "__msan_chain_origin", IRB.getInt32Ty(), IRB.getInt32Ty());
MemmoveFn = M.getOrInsertFunction(
  "__msan_memmove", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
  IRB.getInt8PtrTy(), IntptrTy);
MemcpyFn = M.getOrInsertFunction(
  "__msan_memcpy", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt8PtrTy(),
  IntptrTy);
MemsetFn = M.getOrInsertFunction(
  "__msan_memset", IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IRB.getInt32Ty(),
  IntptrTy);
// We insert an empty inline asm after __msan_report* to avoid callback merge.
EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
                          StringRef(""), StringRef(""),
                          /*hasSideEffects=*/true);

MsanInstrumentAsmStoreFn =
    M.getOrInsertFunction("__msan_instrument_asm_store", IRB.getVoidTy(),
                          PointerType::get(IRB.getInt8Ty(), 0), IntptrTy);

if (CompileKernel) {
  createKernelApi(M);
} else {
  createUserspaceApi(M);
}
CallbacksInitialized = true;
852}

854FunctionCallee MemorySanitizer::getKmsanShadowOriginAccessFn(bool isStore,
                                                           int size) {
FunctionCallee *Fns =
    isStore ? MsanMetadataPtrForStore_1_8 : MsanMetadataPtrForLoad_1_8;
switch (size) {
case 1:
  return Fns[0];
case 2:
  return Fns[1];
case 4:
  return Fns[2];
case 8:
  return Fns[3];
default:
  return nullptr;
}
870}

872/// Module-level initialization.
873///
874/// inserts a call to __msan_init to the module's constructor list.
875void MemorySanitizer::initializeModule(Module &M) {
auto &DL = M.getDataLayout();

bool ShadowPassed = ClShadowBase.getNumOccurrences() > 0;
bool OriginPassed = ClOriginBase.getNumOccurrences() > 0;
// Check the overrides first
if (ShadowPassed || OriginPassed) {
  CustomMapParams.AndMask = ClAndMask;
  CustomMapParams.XorMask = ClXorMask;
  CustomMapParams.ShadowBase = ClShadowBase;
  CustomMapParams.OriginBase = ClOriginBase;
  MapParams = &CustomMapParams;
} else {
  Triple TargetTriple(M.getTargetTriple());
  switch (TargetTriple.getOS()) {
    case Triple::FreeBSD:
      switch (TargetTriple.getArch()) {
        case Triple::x86_64:
          MapParams = FreeBSD_X86_MemoryMapParams.bits64;
          break;
        case Triple::x86:
          MapParams = FreeBSD_X86_MemoryMapParams.bits32;
          break;
        default:
          report_fatal_error("unsupported architecture");
      }
      break;
    case Triple::NetBSD:
      switch (TargetTriple.getArch()) {
        case Triple::x86_64:
          MapParams = NetBSD_X86_MemoryMapParams.bits64;
          break;
        default:
          report_fatal_error("unsupported architecture");
      }
      break;
    case Triple::Linux:
      switch (TargetTriple.getArch()) {
        case Triple::x86_64:
          MapParams = Linux_X86_MemoryMapParams.bits64;
          break;
        case Triple::x86:
          MapParams = Linux_X86_MemoryMapParams.bits32;
          break;
        case Triple::mips64:
        case Triple::mips64el:
          MapParams = Linux_MIPS_MemoryMapParams.bits64;
          break;
        case Triple::ppc64:
        case Triple::ppc64le:
          MapParams = Linux_PowerPC_MemoryMapParams.bits64;
          break;
        case Triple::aarch64:
        case Triple::aarch64_be:
          MapParams = Linux_ARM_MemoryMapParams.bits64;
          break;
        default:
          report_fatal_error("unsupported architecture");
      }
      break;
    default:
      report_fatal_error("unsupported operating system");
  }
}

C = &(M.getContext());
IRBuilder<> IRB(*C);
IntptrTy = IRB.getIntPtrTy(DL);
OriginTy = IRB.getInt32Ty();

ColdCallWeights = MDBuilder(*C).createBranchWeights(1, 1000);
OriginStoreWeights = MDBuilder(*C).createBranchWeights(1, 1000);

if (!CompileKernel) {
  if (TrackOrigins)
    M.getOrInsertGlobal("__msan_track_origins", IRB.getInt32Ty(), [&] {
      return new GlobalVariable(
          M, IRB.getInt32Ty(), true, GlobalValue::WeakODRLinkage,
          IRB.getInt32(TrackOrigins), "__msan_track_origins");
    });

  if (Recover)
    M.getOrInsertGlobal("__msan_keep_going", IRB.getInt32Ty(), [&] {
      return new GlobalVariable(M, IRB.getInt32Ty(), true,
                                GlobalValue::WeakODRLinkage,
                                IRB.getInt32(Recover), "__msan_keep_going");
    });
962}
963}

965bool MemorySanitizerLegacyPass::doInitialization(Module &M) {
if (!Options.Kernel)
  insertModuleCtor(M);
MSan.emplace(M, Options);
return true;
970}

972namespace {

974/// A helper class that handles instrumentation of VarArg
975/// functions on a particular platform.
976///
977/// Implementations are expected to insert the instrumentation
978/// necessary to propagate argument shadow through VarArg function
979/// calls. Visit* methods are called during an InstVisitor pass over
980/// the function, and should avoid creating new basic blocks. A new
981/// instance of this class is created for each instrumented function.
982struct VarArgHelper {
virtual ~VarArgHelper() = default;

/// Visit a CallSite.
virtual void visitCallSite(CallSite &CS, IRBuilder<> &IRB) = 0;

/// Visit a va_start call.
virtual void visitVAStartInst(VAStartInst &I) = 0;

/// Visit a va_copy call.
virtual void visitVACopyInst(VACopyInst &I) = 0;

/// Finalize function instrumentation.
///
/// This method is called after visiting all interesting (see above)
/// instructions in a function.
virtual void finalizeInstrumentation() = 0;
999};

1001struct MemorySanitizerVisitor;

1003} // end anonymous namespace

1005static VarArgHelper *CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
                                      MemorySanitizerVisitor &Visitor);

1008static unsigned TypeSizeToSizeIndex(unsigned TypeSize) {
if (TypeSize <= 8) return 0;
return Log2_32_Ceil((TypeSize + 7) / 8);
1011}

1013namespace {

1015/// This class does all the work for a given function. Store and Load
1016/// instructions store and load corresponding shadow and origin
1017/// values. Most instructions propagate shadow from arguments to their
1018/// return values. Certain instructions (most importantly, BranchInst)
1019/// test their argument shadow and print reports (with a runtime call) if it's
1020/// non-zero.
1021struct MemorySanitizerVisitor : public InstVisitor<MemorySanitizerVisitor> {
Function &F;
MemorySanitizer &MS;
SmallVector<PHINode *, 16> ShadowPHINodes, OriginPHINodes;
ValueMap<Value*, Value*> ShadowMap, OriginMap;
std::unique_ptr<VarArgHelper> VAHelper;
const TargetLibraryInfo *TLI;
BasicBlock *ActualFnStart;

// The following flags disable parts of MSan instrumentation based on
// blacklist contents and command-line options.
bool InsertChecks;
bool PropagateShadow;
bool PoisonStack;
bool PoisonUndef;
bool CheckReturnValue;

struct ShadowOriginAndInsertPoint {
  Value *Shadow;
  Value *Origin;
  Instruction *OrigIns;

  ShadowOriginAndInsertPoint(Value *S, Value *O, Instruction *I)
    : Shadow(S), Origin(O), OrigIns(I) {}
};
SmallVector<ShadowOriginAndInsertPoint, 16> InstrumentationList;
bool InstrumentLifetimeStart = ClHandleLifetimeIntrinsics;
SmallSet<AllocaInst *, 16> AllocaSet;
SmallVector<std::pair<IntrinsicInst *, AllocaInst *>, 16> LifetimeStartList;
SmallVector<StoreInst *, 16> StoreList;

MemorySanitizerVisitor(Function &F, MemorySanitizer &MS,
                       const TargetLibraryInfo &TLI)
    : F(F), MS(MS), VAHelper(CreateVarArgHelper(F, MS, *this)), TLI(&TLI) {
  bool SanitizeFunction = F.hasFnAttribute(Attribute::SanitizeMemory);
  InsertChecks = SanitizeFunction;
  PropagateShadow = SanitizeFunction;
  PoisonStack = SanitizeFunction && ClPoisonStack;
  PoisonUndef = SanitizeFunction && ClPoisonUndef;
  // FIXME: Consider using SpecialCaseList to specify a list of functions that
  // must always return fully initialized values. For now, we hardcode "main".
  CheckReturnValue = SanitizeFunction && (F.getName() == "main");

  MS.initializeCallbacks(*F.getParent());
  if (MS.CompileKernel)
    ActualFnStart = insertKmsanPrologue(F);
  else
    ActualFnStart = &F.getEntryBlock();

  LLVM_DEBUG(if (!InsertChecks) dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { if (!InsertChecks) dbgs() << "MemorySanitizer is not inserting checks into '"
 << F.getName() << "'\n"; } } while (false)
             << "MemorySanitizer is not inserting checks into '"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { if (!InsertChecks) dbgs() << "MemorySanitizer is not inserting checks into '"
 << F.getName() << "'\n"; } } while (false)
             << F.getName() << "'\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { if (!InsertChecks) dbgs() << "MemorySanitizer is not inserting checks into '"
 << F.getName() << "'\n"; } } while (false);
}

Value *updateOrigin(Value *V, IRBuilder<> &IRB) {
  if (MS.TrackOrigins <= 1) return V;
  return IRB.CreateCall(MS.MsanChainOriginFn, V);
}

Value *originToIntptr(IRBuilder<> &IRB, Value *Origin) {
  const DataLayout &DL = F.getParent()->getDataLayout();
  unsigned IntptrSize = DL.getTypeStoreSize(MS.IntptrTy);
  if (IntptrSize == kOriginSize) return Origin;
  assert(IntptrSize == kOriginSize * 2)((IntptrSize == kOriginSize * 2) ? static_cast<void> (0
) : __assert_fail ("IntptrSize == kOriginSize * 2", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1084, __PRETTY_FUNCTION__));
  Origin = IRB.CreateIntCast(Origin, MS.IntptrTy, /* isSigned */ false);
  return IRB.CreateOr(Origin, IRB.CreateShl(Origin, kOriginSize * 8));
}

/// Fill memory range with the given origin value.
void paintOrigin(IRBuilder<> &IRB, Value *Origin, Value *OriginPtr,
                 unsigned Size, Align Alignment) {
  const DataLayout &DL = F.getParent()->getDataLayout();
  const Align IntptrAlignment = Align(DL.getABITypeAlignment(MS.IntptrTy));
  unsigned IntptrSize = DL.getTypeStoreSize(MS.IntptrTy);
  assert(IntptrAlignment >= kMinOriginAlignment)((IntptrAlignment >= kMinOriginAlignment) ? static_cast<
void> (0) : __assert_fail ("IntptrAlignment >= kMinOriginAlignment"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1095, __PRETTY_FUNCTION__));
  assert(IntptrSize >= kOriginSize)((IntptrSize >= kOriginSize) ? static_cast<void> (0)
 : __assert_fail ("IntptrSize >= kOriginSize", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1096, __PRETTY_FUNCTION__));

  unsigned Ofs = 0;
  Align CurrentAlignment = Alignment;
  if (Alignment >= IntptrAlignment && IntptrSize > kOriginSize) {
    Value *IntptrOrigin = originToIntptr(IRB, Origin);
    Value *IntptrOriginPtr =
        IRB.CreatePointerCast(OriginPtr, PointerType::get(MS.IntptrTy, 0));
    for (unsigned i = 0; i < Size / IntptrSize; ++i) {
      Value *Ptr = i ? IRB.CreateConstGEP1_32(MS.IntptrTy, IntptrOriginPtr, i)
                     : IntptrOriginPtr;
      IRB.CreateAlignedStore(IntptrOrigin, Ptr, CurrentAlignment.value());
      Ofs += IntptrSize / kOriginSize;
      CurrentAlignment = IntptrAlignment;
    }
  }

  for (unsigned i = Ofs; i < (Size + kOriginSize - 1) / kOriginSize; ++i) {
    Value *GEP =
        i ? IRB.CreateConstGEP1_32(MS.OriginTy, OriginPtr, i) : OriginPtr;
    IRB.CreateAlignedStore(Origin, GEP, CurrentAlignment.value());
    CurrentAlignment = kMinOriginAlignment;
  }
}

void storeOrigin(IRBuilder<> &IRB, Value *Addr, Value *Shadow, Value *Origin,
                 Value *OriginPtr, Align Alignment, bool AsCall) {
  const DataLayout &DL = F.getParent()->getDataLayout();
  const Align OriginAlignment = std::max(kMinOriginAlignment, Alignment);
  unsigned StoreSize = DL.getTypeStoreSize(Shadow->getType());
  if (Shadow->getType()->isAggregateType()) {
    paintOrigin(IRB, updateOrigin(Origin, IRB), OriginPtr, StoreSize,
                OriginAlignment);
  } else {
    Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
    Constant *ConstantShadow = dyn_cast_or_null<Constant>(ConvertedShadow);
    if (ConstantShadow) {
      if (ClCheckConstantShadow && !ConstantShadow->isZeroValue())
        paintOrigin(IRB, updateOrigin(Origin, IRB), OriginPtr, StoreSize,
                    OriginAlignment);
      return;
    }

    unsigned TypeSizeInBits =
        DL.getTypeSizeInBits(ConvertedShadow->getType());
    unsigned SizeIndex = TypeSizeToSizeIndex(TypeSizeInBits);
    if (AsCall && SizeIndex < kNumberOfAccessSizes && !MS.CompileKernel) {
      FunctionCallee Fn = MS.MaybeStoreOriginFn[SizeIndex];
      Value *ConvertedShadow2 = IRB.CreateZExt(
          ConvertedShadow, IRB.getIntNTy(8 * (1 << SizeIndex)));
      IRB.CreateCall(Fn, {ConvertedShadow2,
                          IRB.CreatePointerCast(Addr, IRB.getInt8PtrTy()),
                          Origin});
    } else {
      Value *Cmp = IRB.CreateICmpNE(
          ConvertedShadow, getCleanShadow(ConvertedShadow), "_mscmp");
      Instruction *CheckTerm = SplitBlockAndInsertIfThen(
          Cmp, &*IRB.GetInsertPoint(), false, MS.OriginStoreWeights);
      IRBuilder<> IRBNew(CheckTerm);
      paintOrigin(IRBNew, updateOrigin(Origin, IRBNew), OriginPtr, StoreSize,
                  OriginAlignment);
    }
  }
}

void materializeStores(bool InstrumentWithCalls) {
  for (StoreInst *SI : StoreList) {
    IRBuilder<> IRB(SI);
    Value *Val = SI->getValueOperand();
    Value *Addr = SI->getPointerOperand();
    Value *Shadow = SI->isAtomic() ? getCleanShadow(Val) : getShadow(Val);
    Value *ShadowPtr, *OriginPtr;
    Type *ShadowTy = Shadow->getType();
    const Align Alignment = assumeAligned(SI->getAlignment());
    const Align OriginAlignment = std::max(kMinOriginAlignment, Alignment);
    std::tie(ShadowPtr, OriginPtr) =
        getShadowOriginPtr(Addr, IRB, ShadowTy, Alignment, /*isStore*/ true);

    StoreInst *NewSI =
        IRB.CreateAlignedStore(Shadow, ShadowPtr, Alignment.value());
    LLVM_DEBUG(dbgs() << "  STORE: " << *NewSI << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "  STORE: " << *NewSI <<
 "\n"; } } while (false);
    (void)NewSI;

    if (SI->isAtomic())
      SI->setOrdering(addReleaseOrdering(SI->getOrdering()));

    if (MS.TrackOrigins && !SI->isAtomic())
      storeOrigin(IRB, Addr, Shadow, getOrigin(Val), OriginPtr,
                  OriginAlignment, InstrumentWithCalls);
  }
}

/// Helper function to insert a warning at IRB's current insert point.
void insertWarningFn(IRBuilder<> &IRB, Value *Origin) {
  if (!Origin)
    Origin = (Value *)IRB.getInt32(0);
  if (MS.CompileKernel) {
    IRB.CreateCall(MS.WarningFn, Origin);
  } else {
    if (MS.TrackOrigins) {
      IRB.CreateStore(Origin, MS.OriginTLS);
    }
    IRB.CreateCall(MS.WarningFn, {});
  }
  IRB.CreateCall(MS.EmptyAsm, {});
  // FIXME: Insert UnreachableInst if !MS.Recover?
  // This may invalidate some of the following checks and needs to be done
  // at the very end.
}

void materializeOneCheck(Instruction *OrigIns, Value *Shadow, Value *Origin,
                         bool AsCall) {
  IRBuilder<> IRB(OrigIns);
  LLVM_DEBUG(dbgs() << "  SHAD0 : " << *Shadow << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "  SHAD0 : " << *Shadow <<
 "\n"; } } while (false);
  Value *ConvertedShadow = convertToShadowTyNoVec(Shadow, IRB);
  LLVM_DEBUG(dbgs() << "  SHAD1 : " << *ConvertedShadow << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "  SHAD1 : " << *ConvertedShadow
 << "\n"; } } while (false);

  Constant *ConstantShadow = dyn_cast_or_null<Constant>(ConvertedShadow);
  if (ConstantShadow) {
    if (ClCheckConstantShadow && !ConstantShadow->isZeroValue()) {
      insertWarningFn(IRB, Origin);
    }
    return;
  }

  const DataLayout &DL = OrigIns->getModule()->getDataLayout();

  unsigned TypeSizeInBits = DL.getTypeSizeInBits(ConvertedShadow->getType());
  unsigned SizeIndex = TypeSizeToSizeIndex(TypeSizeInBits);
  if (AsCall && SizeIndex < kNumberOfAccessSizes && !MS.CompileKernel) {
    FunctionCallee Fn = MS.MaybeWarningFn[SizeIndex];
    Value *ConvertedShadow2 =
        IRB.CreateZExt(ConvertedShadow, IRB.getIntNTy(8 * (1 << SizeIndex)));
    IRB.CreateCall(Fn, {ConvertedShadow2, MS.TrackOrigins && Origin
                                              ? Origin
                                              : (Value *)IRB.getInt32(0)});
  } else {
    Value *Cmp = IRB.CreateICmpNE(ConvertedShadow,
                                  getCleanShadow(ConvertedShadow), "_mscmp");
    Instruction *CheckTerm = SplitBlockAndInsertIfThen(
        Cmp, OrigIns,
        /* Unreachable */ !MS.Recover, MS.ColdCallWeights);

    IRB.SetInsertPoint(CheckTerm);
    insertWarningFn(IRB, Origin);
    LLVM_DEBUG(dbgs() << "  CHECK: " << *Cmp << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "  CHECK: " << *Cmp <<
 "\n"; } } while (false);
  }
}

void materializeChecks(bool InstrumentWithCalls) {
  for (const auto &ShadowData : InstrumentationList) {
    Instruction *OrigIns = ShadowData.OrigIns;
    Value *Shadow = ShadowData.Shadow;
    Value *Origin = ShadowData.Origin;
    materializeOneCheck(OrigIns, Shadow, Origin, InstrumentWithCalls);
  }
  LLVM_DEBUG(dbgs() << "DONE:\n" << F)do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "DONE:\n" << F; } } while (
false);
}

BasicBlock *insertKmsanPrologue(Function &F) {
  BasicBlock *ret =
      SplitBlock(&F.getEntryBlock(), F.getEntryBlock().getFirstNonPHI());
  IRBuilder<> IRB(F.getEntryBlock().getFirstNonPHI());
  Value *ContextState = IRB.CreateCall(MS.MsanGetContextStateFn, {});
  Constant *Zero = IRB.getInt32(0);
  MS.ParamTLS = IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
                              {Zero, IRB.getInt32(0)}, "param_shadow");
  MS.RetvalTLS = IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
                               {Zero, IRB.getInt32(1)}, "retval_shadow");
  MS.VAArgTLS = IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
                              {Zero, IRB.getInt32(2)}, "va_arg_shadow");
  MS.VAArgOriginTLS = IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
                                    {Zero, IRB.getInt32(3)}, "va_arg_origin");
  MS.VAArgOverflowSizeTLS =
      IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
                    {Zero, IRB.getInt32(4)}, "va_arg_overflow_size");
  MS.ParamOriginTLS = IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
                                    {Zero, IRB.getInt32(5)}, "param_origin");
  MS.RetvalOriginTLS =
      IRB.CreateGEP(MS.MsanContextStateTy, ContextState,
                    {Zero, IRB.getInt32(6)}, "retval_origin");
  return ret;
}

/// Add MemorySanitizer instrumentation to a function.
bool runOnFunction() {
  // In the presence of unreachable blocks, we may see Phi nodes with
  // incoming nodes from such blocks. Since InstVisitor skips unreachable
  // blocks, such nodes will not have any shadow value associated with them.
  // It's easier to remove unreachable blocks than deal with missing shadow.
  removeUnreachableBlocks(F);

  // Iterate all BBs in depth-first order and create shadow instructions
  // for all instructions (where applicable).
  // For PHI nodes we create dummy shadow PHIs which will be finalized later.
  for (BasicBlock *BB : depth_first(ActualFnStart))
    visit(*BB);

  // Finalize PHI nodes.
  for (PHINode *PN : ShadowPHINodes) {
    PHINode *PNS = cast<PHINode>(getShadow(PN));
    PHINode *PNO = MS.TrackOrigins ? cast<PHINode>(getOrigin(PN)) : nullptr;
    size_t NumValues = PN->getNumIncomingValues();
    for (size_t v = 0; v < NumValues; v++) {
      PNS->addIncoming(getShadow(PN, v), PN->getIncomingBlock(v));
      if (PNO) PNO->addIncoming(getOrigin(PN, v), PN->getIncomingBlock(v));
    }
  }

  VAHelper->finalizeInstrumentation();

  // Poison llvm.lifetime.start intrinsics, if we haven't fallen back to
  // instrumenting only allocas.
  if (InstrumentLifetimeStart) {
    for (auto Item : LifetimeStartList) {
      instrumentAlloca(*Item.second, Item.first);
      AllocaSet.erase(Item.second);
    }
  }
  // Poison the allocas for which we didn't instrument the corresponding
  // lifetime intrinsics.
  for (AllocaInst *AI : AllocaSet)
    instrumentAlloca(*AI);

  bool InstrumentWithCalls = ClInstrumentationWithCallThreshold >= 0 &&
                             InstrumentationList.size() + StoreList.size() >
                                 (unsigned)ClInstrumentationWithCallThreshold;

  // Insert shadow value checks.
  materializeChecks(InstrumentWithCalls);

  // Delayed instrumentation of StoreInst.
  // This may not add new address checks.
  materializeStores(InstrumentWithCalls);

  return true;
}

/// Compute the shadow type that corresponds to a given Value.
Type *getShadowTy(Value *V) {
  return getShadowTy(V->getType());
}

/// Compute the shadow type that corresponds to a given Type.
Type *getShadowTy(Type *OrigTy) {
  if (!OrigTy->isSized()) {
    return nullptr;
  }
  // For integer type, shadow is the same as the original type.
  // This may return weird-sized types like i1.
  if (IntegerType *IT = dyn_cast<IntegerType>(OrigTy))
    return IT;
  const DataLayout &DL = F.getParent()->getDataLayout();
  if (VectorType *VT = dyn_cast<VectorType>(OrigTy)) {
    uint32_t EltSize = DL.getTypeSizeInBits(VT->getElementType());
    return VectorType::get(IntegerType::get(*MS.C, EltSize),
                           VT->getNumElements());
  }
  if (ArrayType *AT = dyn_cast<ArrayType>(OrigTy)) {
    return ArrayType::get(getShadowTy(AT->getElementType()),
                          AT->getNumElements());
  }
  if (StructType *ST = dyn_cast<StructType>(OrigTy)) {
    SmallVector<Type*, 4> Elements;
    for (unsigned i = 0, n = ST->getNumElements(); i < n; i++)
      Elements.push_back(getShadowTy(ST->getElementType(i)));
    StructType *Res = StructType::get(*MS.C, Elements, ST->isPacked());
    LLVM_DEBUG(dbgs() << "getShadowTy: " << *ST << " ===> " << *Res << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "getShadowTy: " << *ST <<
 " ===> " << *Res << "\n"; } } while (false);
    return Res;
  }
  uint32_t TypeSize = DL.getTypeSizeInBits(OrigTy);
  return IntegerType::get(*MS.C, TypeSize);
}

/// Flatten a vector type.
Type *getShadowTyNoVec(Type *ty) {
  if (VectorType *vt = dyn_cast<VectorType>(ty))
    return IntegerType::get(*MS.C, vt->getBitWidth());
  return ty;
}

/// Convert a shadow value to it's flattened variant.
Value *convertToShadowTyNoVec(Value *V, IRBuilder<> &IRB) {
  Type *Ty = V->getType();
  Type *NoVecTy = getShadowTyNoVec(Ty);
  if (Ty == NoVecTy) return V;
  return IRB.CreateBitCast(V, NoVecTy);
}

/// Compute the integer shadow offset that corresponds to a given
/// application address.
///
/// Offset = (Addr & ~AndMask) ^ XorMask
Value *getShadowPtrOffset(Value *Addr, IRBuilder<> &IRB) {
  Value *OffsetLong = IRB.CreatePointerCast(Addr, MS.IntptrTy);

  uint64_t AndMask = MS.MapParams->AndMask;
  if (AndMask)
    OffsetLong =
        IRB.CreateAnd(OffsetLong, ConstantInt::get(MS.IntptrTy, ~AndMask));

  uint64_t XorMask = MS.MapParams->XorMask;
  if (XorMask)
    OffsetLong =
        IRB.CreateXor(OffsetLong, ConstantInt::get(MS.IntptrTy, XorMask));
  return OffsetLong;
}

/// Compute the shadow and origin addresses corresponding to a given
/// application address.
///
/// Shadow = ShadowBase + Offset
/// Origin = (OriginBase + Offset) & ~3ULL
std::pair<Value *, Value *>
getShadowOriginPtrUserspace(Value *Addr, IRBuilder<> &IRB, Type *ShadowTy,
                            MaybeAlign Alignment) {
  Value *ShadowOffset = getShadowPtrOffset(Addr, IRB);
  Value *ShadowLong = ShadowOffset;
  uint64_t ShadowBase = MS.MapParams->ShadowBase;
  if (ShadowBase != 0) {
    ShadowLong =
      IRB.CreateAdd(ShadowLong,
                    ConstantInt::get(MS.IntptrTy, ShadowBase));
  }
  Value *ShadowPtr =
      IRB.CreateIntToPtr(ShadowLong, PointerType::get(ShadowTy, 0));
  Value *OriginPtr = nullptr;
  if (MS.TrackOrigins) {
    Value *OriginLong = ShadowOffset;
    uint64_t OriginBase = MS.MapParams->OriginBase;
    if (OriginBase != 0)
      OriginLong = IRB.CreateAdd(OriginLong,
                                 ConstantInt::get(MS.IntptrTy, OriginBase));
    if (!Alignment || *Alignment < kMinOriginAlignment) {
      uint64_t Mask = kMinOriginAlignment.value() - 1;
      OriginLong =
          IRB.CreateAnd(OriginLong, ConstantInt::get(MS.IntptrTy, ~Mask));
    }
    OriginPtr =
        IRB.CreateIntToPtr(OriginLong, PointerType::get(MS.OriginTy, 0));
  }
  return std::make_pair(ShadowPtr, OriginPtr);
}

std::pair<Value *, Value *> getShadowOriginPtrKernel(Value *Addr,
                                                     IRBuilder<> &IRB,
                                                     Type *ShadowTy,
                                                     bool isStore) {
  Value *ShadowOriginPtrs;
  const DataLayout &DL = F.getParent()->getDataLayout();
  int Size = DL.getTypeStoreSize(ShadowTy);

  FunctionCallee Getter = MS.getKmsanShadowOriginAccessFn(isStore, Size);
  Value *AddrCast =
      IRB.CreatePointerCast(Addr, PointerType::get(IRB.getInt8Ty(), 0));
  if (Getter) {
    ShadowOriginPtrs = IRB.CreateCall(Getter, AddrCast);
  } else {
    Value *SizeVal = ConstantInt::get(MS.IntptrTy, Size);
    ShadowOriginPtrs = IRB.CreateCall(isStore ? MS.MsanMetadataPtrForStoreN
                                              : MS.MsanMetadataPtrForLoadN,
                                      {AddrCast, SizeVal});
  }
  Value *ShadowPtr = IRB.CreateExtractValue(ShadowOriginPtrs, 0);
  ShadowPtr = IRB.CreatePointerCast(ShadowPtr, PointerType::get(ShadowTy, 0));
  Value *OriginPtr = IRB.CreateExtractValue(ShadowOriginPtrs, 1);

  return std::make_pair(ShadowPtr, OriginPtr);
}

std::pair<Value *, Value *> getShadowOriginPtr(Value *Addr, IRBuilder<> &IRB,
                                               Type *ShadowTy,
                                               MaybeAlign Alignment,
                                               bool isStore) {
  if (MS.CompileKernel)
    return getShadowOriginPtrKernel(Addr, IRB, ShadowTy, isStore);
  return getShadowOriginPtrUserspace(Addr, IRB, ShadowTy, Alignment);
}

/// Compute the shadow address for a given function argument.
///
/// Shadow = ParamTLS+ArgOffset.
Value *getShadowPtrForArgument(Value *A, IRBuilder<> &IRB,
                               int ArgOffset) {
  Value *Base = IRB.CreatePointerCast(MS.ParamTLS, MS.IntptrTy);
  if (ArgOffset)
    Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
  return IRB.CreateIntToPtr(Base, PointerType::get(getShadowTy(A), 0),
                            "_msarg");
}

/// Compute the origin address for a given function argument.
Value *getOriginPtrForArgument(Value *A, IRBuilder<> &IRB,
                               int ArgOffset) {
  if (!MS.TrackOrigins)
    return nullptr;
  Value *Base = IRB.CreatePointerCast(MS.ParamOriginTLS, MS.IntptrTy);
  if (ArgOffset)
    Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
  return IRB.CreateIntToPtr(Base, PointerType::get(MS.OriginTy, 0),
                            "_msarg_o");
}

/// Compute the shadow address for a retval.
Value *getShadowPtrForRetval(Value *A, IRBuilder<> &IRB) {
  return IRB.CreatePointerCast(MS.RetvalTLS,
                               PointerType::get(getShadowTy(A), 0),
                               "_msret");
}

/// Compute the origin address for a retval.
Value *getOriginPtrForRetval(IRBuilder<> &IRB) {
  // We keep a single origin for the entire retval. Might be too optimistic.
  return MS.RetvalOriginTLS;
}

/// Set SV to be the shadow value for V.
void setShadow(Value *V, Value *SV) {
  assert(!ShadowMap.count(V) && "Values may only have one shadow")((!ShadowMap.count(V) && "Values may only have one shadow"
) ? static_cast<void> (0) : __assert_fail ("!ShadowMap.count(V) && \"Values may only have one shadow\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1514, __PRETTY_FUNCTION__));
13
←
Assuming the condition is true→
14
←
'?' condition is true→
  ShadowMap[V] = PropagateShadow ? SV : getCleanShadow(V);
15
←
Assuming field 'PropagateShadow' is true→
16
←
'?' condition is true→
17
←
Value assigned to field 'PropagateShadow', which participates in a condition later→
}

/// Set Origin to be the origin value for V.
void setOrigin(Value *V, Value *Origin) {
  if (!MS.TrackOrigins) return;
  assert(!OriginMap.count(V) && "Values may only have one origin")((!OriginMap.count(V) && "Values may only have one origin"
) ? static_cast<void> (0) : __assert_fail ("!OriginMap.count(V) && \"Values may only have one origin\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1521, __PRETTY_FUNCTION__));
  LLVM_DEBUG(dbgs() << "ORIGIN: " << *V << "  ==> " << *Origin << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "ORIGIN: " << *V << "  ==> "
 << *Origin << "\n"; } } while (false);
  OriginMap[V] = Origin;
}

Constant *getCleanShadow(Type *OrigTy) {
  Type *ShadowTy = getShadowTy(OrigTy);
  if (!ShadowTy)
    return nullptr;
  return Constant::getNullValue(ShadowTy);
}

/// Create a clean shadow value for a given value.
///
/// Clean shadow (all zeroes) means all bits of the value are defined
/// (initialized).
Constant *getCleanShadow(Value *V) {
  return getCleanShadow(V->getType());
}

/// Create a dirty shadow of a given shadow type.
Constant *getPoisonedShadow(Type *ShadowTy) {
  assert(ShadowTy)((ShadowTy) ? static_cast<void> (0) : __assert_fail ("ShadowTy"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1543, __PRETTY_FUNCTION__));
  if (isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy))
    return Constant::getAllOnesValue(ShadowTy);
  if (ArrayType *AT = dyn_cast<ArrayType>(ShadowTy)) {
    SmallVector<Constant *, 4> Vals(AT->getNumElements(),
                                    getPoisonedShadow(AT->getElementType()));
    return ConstantArray::get(AT, Vals);
  }
  if (StructType *ST = dyn_cast<StructType>(ShadowTy)) {
    SmallVector<Constant *, 4> Vals;
    for (unsigned i = 0, n = ST->getNumElements(); i < n; i++)
      Vals.push_back(getPoisonedShadow(ST->getElementType(i)));
    return ConstantStruct::get(ST, Vals);
  }
  llvm_unreachable("Unexpected shadow type")::llvm::llvm_unreachable_internal("Unexpected shadow type", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1557);
}

/// Create a dirty shadow for a given value.
Constant *getPoisonedShadow(Value *V) {
  Type *ShadowTy = getShadowTy(V);
  if (!ShadowTy)
    return nullptr;
  return getPoisonedShadow(ShadowTy);
}

/// Create a clean (zero) origin.
Value *getCleanOrigin() {
  return Constant::getNullValue(MS.OriginTy);
}

/// Get the shadow value for a given Value.
///
/// This function either returns the value set earlier with setShadow,
/// or extracts if from ParamTLS (for function arguments).
Value *getShadow(Value *V) {
  if (!PropagateShadow) return getCleanShadow(V);
  if (Instruction *I = dyn_cast<Instruction>(V)) {
    if (I->getMetadata("nosanitize"))
      return getCleanShadow(V);
    // For instructions the shadow is already stored in the map.
    Value *Shadow = ShadowMap[V];
    if (!Shadow) {
      LLVM_DEBUG(dbgs() << "No shadow: " << *V << "\n" << *(I->getParent()))do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "No shadow: " << *V <<
 "\n" << *(I->getParent()); } } while (false);
      (void)I;
      assert(Shadow && "No shadow for a value")((Shadow && "No shadow for a value") ? static_cast<
void> (0) : __assert_fail ("Shadow && \"No shadow for a value\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1587, __PRETTY_FUNCTION__));
    }
    return Shadow;
  }
  if (UndefValue *U = dyn_cast<UndefValue>(V)) {
    Value *AllOnes = PoisonUndef ? getPoisonedShadow(V) : getCleanShadow(V);
    LLVM_DEBUG(dbgs() << "Undef: " << *U << " ==> " << *AllOnes << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "Undef: " << *U << " ==> "
 << *AllOnes << "\n"; } } while (false);
    (void)U;
    return AllOnes;
  }
  if (Argument *A = dyn_cast<Argument>(V)) {
    // For arguments we compute the shadow on demand and store it in the map.
    Value **ShadowPtr = &ShadowMap[V];
    if (*ShadowPtr)
      return *ShadowPtr;
    Function *F = A->getParent();
    IRBuilder<> EntryIRB(ActualFnStart->getFirstNonPHI());
    unsigned ArgOffset = 0;
    const DataLayout &DL = F->getParent()->getDataLayout();
    for (auto &FArg : F->args()) {
      if (!FArg.getType()->isSized()) {
        LLVM_DEBUG(dbgs() << "Arg is not sized\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "Arg is not sized\n"; } } while (
false);
        continue;
      }
      unsigned Size =
          FArg.hasByValAttr()
              ? DL.getTypeAllocSize(FArg.getType()->getPointerElementType())
              : DL.getTypeAllocSize(FArg.getType());
      if (A == &FArg) {
        bool Overflow = ArgOffset + Size > kParamTLSSize;
        Value *Base = getShadowPtrForArgument(&FArg, EntryIRB, ArgOffset);
        if (FArg.hasByValAttr()) {
          // ByVal pointer itself has clean shadow. We copy the actual
          // argument shadow to the underlying memory.
          // Figure out maximal valid memcpy alignment.
          const Align ArgAlign = DL.getValueOrABITypeAlignment(
              MaybeAlign(FArg.getParamAlignment()),
              A->getType()->getPointerElementType());
          Value *CpShadowPtr =
              getShadowOriginPtr(V, EntryIRB, EntryIRB.getInt8Ty(), ArgAlign,
                                 /*isStore*/ true)
                  .first;
          // TODO(glider): need to copy origins.
          if (Overflow) {
            // ParamTLS overflow.
            EntryIRB.CreateMemSet(
                CpShadowPtr, Constant::getNullValue(EntryIRB.getInt8Ty()),
                Size, ArgAlign);
          } else {
            const Align CopyAlign = std::min(ArgAlign, kShadowTLSAlignment);
            Value *Cpy = EntryIRB.CreateMemCpy(CpShadowPtr, CopyAlign, Base,
                                               CopyAlign, Size);
            LLVM_DEBUG(dbgs() << "  ByValCpy: " << *Cpy << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "  ByValCpy: " << *Cpy <<
 "\n"; } } while (false);
            (void)Cpy;
          }
          *ShadowPtr = getCleanShadow(V);
        } else {
          if (Overflow) {
            // ParamTLS overflow.
            *ShadowPtr = getCleanShadow(V);
          } else {
            *ShadowPtr = EntryIRB.CreateAlignedLoad(
                getShadowTy(&FArg), Base, kShadowTLSAlignment.value());
          }
        }
        LLVM_DEBUG(dbgs()do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "  ARG:    " << FArg <<
 " ==> " << **ShadowPtr << "\n"; } } while (false
)
                   << "  ARG:    " << FArg << " ==> " << **ShadowPtr << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "  ARG:    " << FArg <<
 " ==> " << **ShadowPtr << "\n"; } } while (false
);
        if (MS.TrackOrigins && !Overflow) {
          Value *OriginPtr =
              getOriginPtrForArgument(&FArg, EntryIRB, ArgOffset);
          setOrigin(A, EntryIRB.CreateLoad(MS.OriginTy, OriginPtr));
        } else {
          setOrigin(A, getCleanOrigin());
        }
      }
      ArgOffset += alignTo(Size, kShadowTLSAlignment);
    }
    assert(*ShadowPtr && "Could not find shadow for an argument")((*ShadowPtr && "Could not find shadow for an argument"
) ? static_cast<void> (0) : __assert_fail ("*ShadowPtr && \"Could not find shadow for an argument\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1664, __PRETTY_FUNCTION__));
    return *ShadowPtr;
  }
  // For everything else the shadow is zero.
  return getCleanShadow(V);
}

/// Get the shadow for i-th argument of the instruction I.
Value *getShadow(Instruction *I, int i) {
  return getShadow(I->getOperand(i));
}

/// Get the origin for a value.
Value *getOrigin(Value *V) {
  if (!MS.TrackOrigins) return nullptr;
  if (!PropagateShadow) return getCleanOrigin();
  if (isa<Constant>(V)) return getCleanOrigin();
  assert((isa<Instruction>(V) || isa<Argument>(V)) &&(((isa<Instruction>(V) || isa<Argument>(V)) &&
 "Unexpected value type in getOrigin()") ? static_cast<void
> (0) : __assert_fail ("(isa<Instruction>(V) || isa<Argument>(V)) && \"Unexpected value type in getOrigin()\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1682, __PRETTY_FUNCTION__))
         "Unexpected value type in getOrigin()")(((isa<Instruction>(V) || isa<Argument>(V)) &&
 "Unexpected value type in getOrigin()") ? static_cast<void
> (0) : __assert_fail ("(isa<Instruction>(V) || isa<Argument>(V)) && \"Unexpected value type in getOrigin()\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1682, __PRETTY_FUNCTION__));
  if (Instruction *I = dyn_cast<Instruction>(V)) {
    if (I->getMetadata("nosanitize"))
      return getCleanOrigin();
  }
  Value *Origin = OriginMap[V];
  assert(Origin && "Missing origin")((Origin && "Missing origin") ? static_cast<void>
 (0) : __assert_fail ("Origin && \"Missing origin\"",
 "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1688, __PRETTY_FUNCTION__));
  return Origin;
}

/// Get the origin for i-th argument of the instruction I.
Value *getOrigin(Instruction *I, int i) {
  return getOrigin(I->getOperand(i));
}

/// Remember the place where a shadow check should be inserted.
///
/// This location will be later instrumented with a check that will print a
/// UMR warning in runtime if the shadow value is not 0.
void insertShadowCheck(Value *Shadow, Value *Origin, Instruction *OrigIns) {
  assert(Shadow)((Shadow) ? static_cast<void> (0) : __assert_fail ("Shadow"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1702, __PRETTY_FUNCTION__));
  if (!InsertChecks) return;
1704#ifndef NDEBUG
  Type *ShadowTy = Shadow->getType();
  assert((isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy)) &&(((isa<IntegerType>(ShadowTy) || isa<VectorType>(
ShadowTy)) && "Can only insert checks for integer and vector shadow types"
) ? static_cast<void> (0) : __assert_fail ("(isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy)) && \"Can only insert checks for integer and vector shadow types\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1707, __PRETTY_FUNCTION__))
         "Can only insert checks for integer and vector shadow types")(((isa<IntegerType>(ShadowTy) || isa<VectorType>(
ShadowTy)) && "Can only insert checks for integer and vector shadow types"
) ? static_cast<void> (0) : __assert_fail ("(isa<IntegerType>(ShadowTy) || isa<VectorType>(ShadowTy)) && \"Can only insert checks for integer and vector shadow types\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1707, __PRETTY_FUNCTION__));
1708#endif
  InstrumentationList.push_back(
      ShadowOriginAndInsertPoint(Shadow, Origin, OrigIns));
}

/// Remember the place where a shadow check should be inserted.
///
/// This location will be later instrumented with a check that will print a
/// UMR warning in runtime if the value is not fully defined.
void insertShadowCheck(Value *Val, Instruction *OrigIns) {
  assert(Val)((Val) ? static_cast<void> (0) : __assert_fail ("Val", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1718, __PRETTY_FUNCTION__));
  Value *Shadow, *Origin;
  if (ClCheckConstantShadow) {
    Shadow = getShadow(Val);
    if (!Shadow) return;
    Origin = getOrigin(Val);
  } else {
    Shadow = dyn_cast_or_null<Instruction>(getShadow(Val));
    if (!Shadow) return;
    Origin = dyn_cast_or_null<Instruction>(getOrigin(Val));
  }
  insertShadowCheck(Shadow, Origin, OrigIns);
}

AtomicOrdering addReleaseOrdering(AtomicOrdering a) {
  switch (a) {
    case AtomicOrdering::NotAtomic:
      return AtomicOrdering::NotAtomic;
    case AtomicOrdering::Unordered:
    case AtomicOrdering::Monotonic:
    case AtomicOrdering::Release:
      return AtomicOrdering::Release;
    case AtomicOrdering::Acquire:
    case AtomicOrdering::AcquireRelease:
      return AtomicOrdering::AcquireRelease;
    case AtomicOrdering::SequentiallyConsistent:
      return AtomicOrdering::SequentiallyConsistent;
  }
  llvm_unreachable("Unknown ordering")::llvm::llvm_unreachable_internal("Unknown ordering", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1746);
}

AtomicOrdering addAcquireOrdering(AtomicOrdering a) {
  switch (a) {
    case AtomicOrdering::NotAtomic:
      return AtomicOrdering::NotAtomic;
    case AtomicOrdering::Unordered:
    case AtomicOrdering::Monotonic:
    case AtomicOrdering::Acquire:
      return AtomicOrdering::Acquire;
    case AtomicOrdering::Release:
    case AtomicOrdering::AcquireRelease:
      return AtomicOrdering::AcquireRelease;
    case AtomicOrdering::SequentiallyConsistent:
      return AtomicOrdering::SequentiallyConsistent;
  }
  llvm_unreachable("Unknown ordering")::llvm::llvm_unreachable_internal("Unknown ordering", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1763);
}

// ------------------- Visitors.
using InstVisitor<MemorySanitizerVisitor>::visit;
void visit(Instruction &I) {
  if (!I.getMetadata("nosanitize"))
    InstVisitor<MemorySanitizerVisitor>::visit(I);
}

/// Instrument LoadInst
///
/// Loads the corresponding shadow and (optionally) origin.
/// Optionally, checks that the load address is fully defined.
void visitLoadInst(LoadInst &I) {
  assert(I.getType()->isSized() && "Load type must have size")((I.getType()->isSized() && "Load type must have size"
) ? static_cast<void> (0) : __assert_fail ("I.getType()->isSized() && \"Load type must have size\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1778, __PRETTY_FUNCTION__));
  assert(!I.getMetadata("nosanitize"))((!I.getMetadata("nosanitize")) ? static_cast<void> (0)
 : __assert_fail ("!I.getMetadata(\"nosanitize\")", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1779, __PRETTY_FUNCTION__));
  IRBuilder<> IRB(I.getNextNode());
  Type *ShadowTy = getShadowTy(&I);
  Value *Addr = I.getPointerOperand();
  Value *ShadowPtr, *OriginPtr;
  const Align Alignment = assumeAligned(I.getAlignment());
  if (PropagateShadow) {
    std::tie(ShadowPtr, OriginPtr) =
        getShadowOriginPtr(Addr, IRB, ShadowTy, Alignment, /*isStore*/ false);
    setShadow(&I, IRB.CreateAlignedLoad(ShadowTy, ShadowPtr,
                                        Alignment.value(), "_msld"));
  } else {
    setShadow(&I, getCleanShadow(&I));
  }

  if (ClCheckAccessAddress)
    insertShadowCheck(I.getPointerOperand(), &I);

  if (I.isAtomic())
    I.setOrdering(addAcquireOrdering(I.getOrdering()));

  if (MS.TrackOrigins) {
    if (PropagateShadow) {
      const Align OriginAlignment = std::max(kMinOriginAlignment, Alignment);
      setOrigin(&I, IRB.CreateAlignedLoad(MS.OriginTy, OriginPtr,
                                          OriginAlignment.value()));
    } else {
      setOrigin(&I, getCleanOrigin());
    }
  }
}

/// Instrument StoreInst
///
/// Stores the corresponding shadow and (optionally) origin.
/// Optionally, checks that the store address is fully defined.
void visitStoreInst(StoreInst &I) {
  StoreList.push_back(&I);
  if (ClCheckAccessAddress)
    insertShadowCheck(I.getPointerOperand(), &I);
}

void handleCASOrRMW(Instruction &I) {
  assert(isa<AtomicRMWInst>(I) || isa<AtomicCmpXchgInst>(I))((isa<AtomicRMWInst>(I) || isa<AtomicCmpXchgInst>
(I)) ? static_cast<void> (0) : __assert_fail ("isa<AtomicRMWInst>(I) || isa<AtomicCmpXchgInst>(I)"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 1822, __PRETTY_FUNCTION__));

  IRBuilder<> IRB(&I);
  Value *Addr = I.getOperand(0);
  Value *ShadowPtr = getShadowOriginPtr(Addr, IRB, I.getType(), Align::None(),
                                        /*isStore*/ true)
                         .first;

  if (ClCheckAccessAddress)
    insertShadowCheck(Addr, &I);

  // Only test the conditional argument of cmpxchg instruction.
  // The other argument can potentially be uninitialized, but we can not
  // detect this situation reliably without possible false positives.
  if (isa<AtomicCmpXchgInst>(I))
    insertShadowCheck(I.getOperand(1), &I);

  IRB.CreateStore(getCleanShadow(&I), ShadowPtr);

  setShadow(&I, getCleanShadow(&I));
  setOrigin(&I, getCleanOrigin());
}

void visitAtomicRMWInst(AtomicRMWInst &I) {
  handleCASOrRMW(I);
  I.setOrdering(addReleaseOrdering(I.getOrdering()));
}

void visitAtomicCmpXchgInst(AtomicCmpXchgInst &I) {
  handleCASOrRMW(I);
  I.setSuccessOrdering(addReleaseOrdering(I.getSuccessOrdering()));
}

// Vector manipulation.
void visitExtractElementInst(ExtractElementInst &I) {
  insertShadowCheck(I.getOperand(1), &I);
  IRBuilder<> IRB(&I);
  setShadow(&I, IRB.CreateExtractElement(getShadow(&I, 0), I.getOperand(1),
            "_msprop"));
  setOrigin(&I, getOrigin(&I, 0));
}

void visitInsertElementInst(InsertElementInst &I) {
  insertShadowCheck(I.getOperand(2), &I);
  IRBuilder<> IRB(&I);
  setShadow(&I, IRB.CreateInsertElement(getShadow(&I, 0), getShadow(&I, 1),
            I.getOperand(2), "_msprop"));
  setOriginForNaryOp(I);
}

void visitShuffleVectorInst(ShuffleVectorInst &I) {
  insertShadowCheck(I.getOperand(2), &I);
  IRBuilder<> IRB(&I);
  setShadow(&I, IRB.CreateShuffleVector(getShadow(&I, 0), getShadow(&I, 1),
            I.getOperand(2), "_msprop"));
  setOriginForNaryOp(I);
}

// Casts.
void visitSExtInst(SExtInst &I) {
  IRBuilder<> IRB(&I);
  setShadow(&I, IRB.CreateSExt(getShadow(&I, 0), I.getType(), "_msprop"));
  setOrigin(&I, getOrigin(&I, 0));
}

void visitZExtInst(ZExtInst &I) {
  IRBuilder<> IRB(&I);
  setShadow(&I, IRB.CreateZExt(getShadow(&I, 0), I.getType(), "_msprop"));
  setOrigin(&I, getOrigin(&I, 0));
}

void visitTruncInst(TruncInst &I) {
  IRBuilder<> IRB(&I);
  setShadow(&I, IRB.CreateTrunc(getShadow(&I, 0), I.getType(), "_msprop"));
  setOrigin(&I, getOrigin(&I, 0));
}

void visitBitCastInst(BitCastInst &I) {
  // Special case: if this is the bitcast (there is exactly 1 allowed) between
  // a musttail call and a ret, don't instrument. New instructions are not
  // allowed after a musttail call.
  if (auto *CI = dyn_cast<CallInst>(I.getOperand(0)))
    if (CI->isMustTailCall())
      return;
  IRBuilder<> IRB(&I);
  setShadow(&I, IRB.CreateBitCast(getShadow(&I, 0), getShadowTy(&I)));
  setOrigin(&I, getOrigin(&I, 0));
}

void visitPtrToIntInst(PtrToIntInst &I) {
  IRBuilder<> IRB(&I);
  setShadow(&I, IRB.CreateIntCast(getShadow(&I, 0), getShadowTy(&I), false,
           "_msprop_ptrtoint"));
  setOrigin(&I, getOrigin(&I, 0));
}

void visitIntToPtrInst(IntToPtrInst &I) {
  IRBuilder<> IRB(&I);
  setShadow(&I, IRB.CreateIntCast(getShadow(&I, 0), getShadowTy(&I), false,
           "_msprop_inttoptr"));
  setOrigin(&I, getOrigin(&I, 0));
}

void visitFPToSIInst(CastInst& I) { handleShadowOr(I); }
void visitFPToUIInst(CastInst& I) { handleShadowOr(I); }
void visitSIToFPInst(CastInst& I) { handleShadowOr(I); }
void visitUIToFPInst(CastInst& I) { handleShadowOr(I); }
void visitFPExtInst(CastInst& I) { handleShadowOr(I); }
void visitFPTruncInst(CastInst& I) { handleShadowOr(I); }

/// Propagate shadow for bitwise AND.
///
/// This code is exact, i.e. if, for example, a bit in the left argument
/// is defined and 0, then neither the value not definedness of the
/// corresponding bit in B don't affect the resulting shadow.
void visitAnd(BinaryOperator &I) {
  IRBuilder<> IRB(&I);
  //  "And" of 0 and a poisoned value results in unpoisoned value.
  //  1&1 => 1;     0&1 => 0;     p&1 => p;
  //  1&0 => 0;     0&0 => 0;     p&0 => 0;
  //  1&p => p;     0&p => 0;     p&p => p;
  //  S = (S1 & S2) | (V1 & S2) | (S1 & V2)
  Value *S1 = getShadow(&I, 0);
  Value *S2 = getShadow(&I, 1);
  Value *V1 = I.getOperand(0);
  Value *V2 = I.getOperand(1);
  if (V1->getType() != S1->getType()) {
    V1 = IRB.CreateIntCast(V1, S1->getType(), false);
    V2 = IRB.CreateIntCast(V2, S2->getType(), false);
  }
  Value *S1S2 = IRB.CreateAnd(S1, S2);
  Value *V1S2 = IRB.CreateAnd(V1, S2);
  Value *S1V2 = IRB.CreateAnd(S1, V2);
  setShadow(&I, IRB.CreateOr({S1S2, V1S2, S1V2}));
  setOriginForNaryOp(I);
}

void visitOr(BinaryOperator &I) {
  IRBuilder<> IRB(&I);
  //  "Or" of 1 and a poisoned value results in unpoisoned value.
  //  1|1 => 1;     0|1 => 1;     p|1 => 1;
  //  1|0 => 1;     0|0 => 0;     p|0 => p;
  //  1|p => 1;     0|p => p;     p|p => p;
  //  S = (S1 & S2) | (~V1 & S2) | (S1 & ~V2)
  Value *S1 = getShadow(&I, 0);
  Value *S2 = getShadow(&I, 1);
  Value *V1 = IRB.CreateNot(I.getOperand(0));
  Value *V2 = IRB.CreateNot(I.getOperand(1));
  if (V1->getType() != S1->getType()) {
    V1 = IRB.CreateIntCast(V1, S1->getType(), false);
    V2 = IRB.CreateIntCast(V2, S2->getType(), false);
  }
  Value *S1S2 = IRB.CreateAnd(S1, S2);
  Value *V1S2 = IRB.CreateAnd(V1, S2);
  Value *S1V2 = IRB.CreateAnd(S1, V2);
  setShadow(&I, IRB.CreateOr({S1S2, V1S2, S1V2}));
  setOriginForNaryOp(I);
}

/// Default propagation of shadow and/or origin.
///
/// This class implements the general case of shadow propagation, used in all
/// cases where we don't know and/or don't care about what the operation
/// actually does. It converts all input shadow values to a common type
/// (extending or truncating as necessary), and bitwise OR's them.
///
/// This is much cheaper than inserting checks (i.e. requiring inputs to be
/// fully initialized), and less prone to false positives.
///
/// This class also implements the general case of origin propagation. For a
/// Nary operation, result origin is set to the origin of an argument that is
/// not entirely initialized. If there is more than one such arguments, the
/// rightmost of them is picked. It does not matter which one is picked if all
/// arguments are initialized.
template <bool CombineShadow>
class Combiner {
  Value *Shadow = nullptr;
  Value *Origin = nullptr;
  IRBuilder<> &IRB;
  MemorySanitizerVisitor *MSV;

public:
  Combiner(MemorySanitizerVisitor *MSV, IRBuilder<> &IRB)
      : IRB(IRB), MSV(MSV) {}

  /// Add a pair of shadow and origin values to the mix.
  Combiner &Add(Value *OpShadow, Value *OpOrigin) {
    if (CombineShadow) {
      assert(OpShadow)((OpShadow) ? static_cast<void> (0) : __assert_fail ("OpShadow"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2010, __PRETTY_FUNCTION__));
      if (!Shadow)
        Shadow = OpShadow;
      else {
        OpShadow = MSV->CreateShadowCast(IRB, OpShadow, Shadow->getType());
        Shadow = IRB.CreateOr(Shadow, OpShadow, "_msprop");
      }
    }

    if (MSV->MS.TrackOrigins) {
      assert(OpOrigin)((OpOrigin) ? static_cast<void> (0) : __assert_fail ("OpOrigin"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2020, __PRETTY_FUNCTION__));
      if (!Origin) {
        Origin = OpOrigin;
      } else {
        Constant *ConstOrigin = dyn_cast<Constant>(OpOrigin);
        // No point in adding something that might result in 0 origin value.
        if (!ConstOrigin || !ConstOrigin->isNullValue()) {
          Value *FlatShadow = MSV->convertToShadowTyNoVec(OpShadow, IRB);
          Value *Cond =
              IRB.CreateICmpNE(FlatShadow, MSV->getCleanShadow(FlatShadow));
          Origin = IRB.CreateSelect(Cond, OpOrigin, Origin);
        }
      }
    }
    return *this;
  }

  /// Add an application value to the mix.
  Combiner &Add(Value *V) {
    Value *OpShadow = MSV->getShadow(V);
    Value *OpOrigin = MSV->MS.TrackOrigins ? MSV->getOrigin(V) : nullptr;
    return Add(OpShadow, OpOrigin);
  }

  /// Set the current combined values as the given instruction's shadow
  /// and origin.
  void Done(Instruction *I) {
    if (CombineShadow) {
      assert(Shadow)((Shadow) ? static_cast<void> (0) : __assert_fail ("Shadow"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2048, __PRETTY_FUNCTION__));
      Shadow = MSV->CreateShadowCast(IRB, Shadow, MSV->getShadowTy(I));
      MSV->setShadow(I, Shadow);
    }
    if (MSV->MS.TrackOrigins) {
      assert(Origin)((Origin) ? static_cast<void> (0) : __assert_fail ("Origin"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2053, __PRETTY_FUNCTION__));
      MSV->setOrigin(I, Origin);
    }
  }
};

using ShadowAndOriginCombiner = Combiner<true>;
using OriginCombiner = Combiner<false>;

/// Propagate origin for arbitrary operation.
void setOriginForNaryOp(Instruction &I) {
  if (!MS.TrackOrigins) return;
  IRBuilder<> IRB(&I);
  OriginCombiner OC(this, IRB);
  for (Instruction::op_iterator OI = I.op_begin(); OI != I.op_end(); ++OI)
    OC.Add(OI->get());
  OC.Done(&I);
}

size_t VectorOrPrimitiveTypeSizeInBits(Type *Ty) {
  assert(!(Ty->isVectorTy() && Ty->getScalarType()->isPointerTy()) &&((!(Ty->isVectorTy() && Ty->getScalarType()->
isPointerTy()) && "Vector of pointers is not a valid shadow type"
) ? static_cast<void> (0) : __assert_fail ("!(Ty->isVectorTy() && Ty->getScalarType()->isPointerTy()) && \"Vector of pointers is not a valid shadow type\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2074, __PRETTY_FUNCTION__))
         "Vector of pointers is not a valid shadow type")((!(Ty->isVectorTy() && Ty->getScalarType()->
isPointerTy()) && "Vector of pointers is not a valid shadow type"
) ? static_cast<void> (0) : __assert_fail ("!(Ty->isVectorTy() && Ty->getScalarType()->isPointerTy()) && \"Vector of pointers is not a valid shadow type\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2074, __PRETTY_FUNCTION__));
  return Ty->isVectorTy() ?
    Ty->getVectorNumElements() * Ty->getScalarSizeInBits() :
    Ty->getPrimitiveSizeInBits();
}

/// Cast between two shadow types, extending or truncating as
/// necessary.
Value *CreateShadowCast(IRBuilder<> &IRB, Value *V, Type *dstTy,
                        bool Signed = false) {
  Type *srcTy = V->getType();
  size_t srcSizeInBits = VectorOrPrimitiveTypeSizeInBits(srcTy);
  size_t dstSizeInBits = VectorOrPrimitiveTypeSizeInBits(dstTy);
  if (srcSizeInBits > 1 && dstSizeInBits == 1)
    return IRB.CreateICmpNE(V, getCleanShadow(V));

  if (dstTy->isIntegerTy() && srcTy->isIntegerTy())
    return IRB.CreateIntCast(V, dstTy, Signed);
  if (dstTy->isVectorTy() && srcTy->isVectorTy() &&
      dstTy->getVectorNumElements() == srcTy->getVectorNumElements())
    return IRB.CreateIntCast(V, dstTy, Signed);
  Value *V1 = IRB.CreateBitCast(V, Type::getIntNTy(*MS.C, srcSizeInBits));
  Value *V2 =
    IRB.CreateIntCast(V1, Type::getIntNTy(*MS.C, dstSizeInBits), Signed);
  return IRB.CreateBitCast(V2, dstTy);
  // TODO: handle struct types.
}

/// Cast an application value to the type of its own shadow.
Value *CreateAppToShadowCast(IRBuilder<> &IRB, Value *V) {
  Type *ShadowTy = getShadowTy(V);
  if (V->getType() == ShadowTy)
    return V;
  if (V->getType()->isPtrOrPtrVectorTy())
    return IRB.CreatePtrToInt(V, ShadowTy);
  else
    return IRB.CreateBitCast(V, ShadowTy);
}

/// Propagate shadow for arbitrary operation.
void handleShadowOr(Instruction &I) {
  IRBuilder<> IRB(&I);
  ShadowAndOriginCombiner SC(this, IRB);
  for (Instruction::op_iterator OI = I.op_begin(); OI != I.op_end(); ++OI)
    SC.Add(OI->get());
  SC.Done(&I);
}

void visitFNeg(UnaryOperator &I) { handleShadowOr(I); }

// Handle multiplication by constant.
//
// Handle a special case of multiplication by constant that may have one or
// more zeros in the lower bits. This makes corresponding number of lower bits
// of the result zero as well. We model it by shifting the other operand
// shadow left by the required number of bits. Effectively, we transform
// (X * (A * 2**B)) to ((X << B) * A) and instrument (X << B) as (Sx << B).
// We use multiplication by 2**N instead of shift to cover the case of
// multiplication by 0, which may occur in some elements of a vector operand.
void handleMulByConstant(BinaryOperator &I, Constant *ConstArg,
                         Value *OtherArg) {
  Constant *ShadowMul;
  Type *Ty = ConstArg->getType();
  if (Ty->isVectorTy()) {
    unsigned NumElements = Ty->getVectorNumElements();
    Type *EltTy = Ty->getSequentialElementType();
    SmallVector<Constant *, 16> Elements;
    for (unsigned Idx = 0; Idx < NumElements; ++Idx) {
      if (ConstantInt *Elt =
              dyn_cast<ConstantInt>(ConstArg->getAggregateElement(Idx))) {
        const APInt &V = Elt->getValue();
        APInt V2 = APInt(V.getBitWidth(), 1) << V.countTrailingZeros();
        Elements.push_back(ConstantInt::get(EltTy, V2));
      } else {
        Elements.push_back(ConstantInt::get(EltTy, 1));
      }
    }
    ShadowMul = ConstantVector::get(Elements);
  } else {
    if (ConstantInt *Elt = dyn_cast<ConstantInt>(ConstArg)) {
      const APInt &V = Elt->getValue();
      APInt V2 = APInt(V.getBitWidth(), 1) << V.countTrailingZeros();
      ShadowMul = ConstantInt::get(Ty, V2);
    } else {
      ShadowMul = ConstantInt::get(Ty, 1);
    }
  }

  IRBuilder<> IRB(&I);
  setShadow(&I,
            IRB.CreateMul(getShadow(OtherArg), ShadowMul, "msprop_mul_cst"));
  setOrigin(&I, getOrigin(OtherArg));
}

void visitMul(BinaryOperator &I) {
  Constant *constOp0 = dyn_cast<Constant>(I.getOperand(0));
  Constant *constOp1 = dyn_cast<Constant>(I.getOperand(1));
  if (constOp0 && !constOp1)
    handleMulByConstant(I, constOp0, I.getOperand(1));
  else if (constOp1 && !constOp0)
    handleMulByConstant(I, constOp1, I.getOperand(0));
  else
    handleShadowOr(I);
}

void visitFAdd(BinaryOperator &I) { handleShadowOr(I); }
void visitFSub(BinaryOperator &I) { handleShadowOr(I); }
void visitFMul(BinaryOperator &I) { handleShadowOr(I); }
void visitAdd(BinaryOperator &I) { handleShadowOr(I); }
void visitSub(BinaryOperator &I) { handleShadowOr(I); }
void visitXor(BinaryOperator &I) { handleShadowOr(I); }

void handleIntegerDiv(Instruction &I) {
  IRBuilder<> IRB(&I);
  // Strict on the second argument.
  insertShadowCheck(I.getOperand(1), &I);
  setShadow(&I, getShadow(&I, 0));
  setOrigin(&I, getOrigin(&I, 0));
}

void visitUDiv(BinaryOperator &I) { handleIntegerDiv(I); }
void visitSDiv(BinaryOperator &I) { handleIntegerDiv(I); }
void visitURem(BinaryOperator &I) { handleIntegerDiv(I); }
void visitSRem(BinaryOperator &I) { handleIntegerDiv(I); }

// Floating point division is side-effect free. We can not require that the
// divisor is fully initialized and must propagate shadow. See PR37523.
void visitFDiv(BinaryOperator &I) { handleShadowOr(I); }
void visitFRem(BinaryOperator &I) { handleShadowOr(I); }

/// Instrument == and != comparisons.
///
/// Sometimes the comparison result is known even if some of the bits of the
/// arguments are not.
void handleEqualityComparison(ICmpInst &I) {
  IRBuilder<> IRB(&I);
  Value *A = I.getOperand(0);
  Value *B = I.getOperand(1);
  Value *Sa = getShadow(A);
  Value *Sb = getShadow(B);

  // Get rid of pointers and vectors of pointers.
  // For ints (and vectors of ints), types of A and Sa match,
  // and this is a no-op.
  A = IRB.CreatePointerCast(A, Sa->getType());
  B = IRB.CreatePointerCast(B, Sb->getType());

  // A == B  <==>  (C = A^B) == 0
  // A != B  <==>  (C = A^B) != 0
  // Sc = Sa | Sb
  Value *C = IRB.CreateXor(A, B);
  Value *Sc = IRB.CreateOr(Sa, Sb);
  // Now dealing with i = (C == 0) comparison (or C != 0, does not matter now)
  // Result is defined if one of the following is true
  // * there is a defined 1 bit in C
  // * C is fully defined
  // Si = !(C & ~Sc) && Sc
  Value *Zero = Constant::getNullValue(Sc->getType());
  Value *MinusOne = Constant::getAllOnesValue(Sc->getType());
  Value *Si =
    IRB.CreateAnd(IRB.CreateICmpNE(Sc, Zero),
                  IRB.CreateICmpEQ(
                    IRB.CreateAnd(IRB.CreateXor(Sc, MinusOne), C), Zero));
  Si->setName("_msprop_icmp");
  setShadow(&I, Si);
  setOriginForNaryOp(I);
}

/// Build the lowest possible value of V, taking into account V's
///        uninitialized bits.
Value *getLowestPossibleValue(IRBuilder<> &IRB, Value *A, Value *Sa,
                              bool isSigned) {
  if (isSigned) {
    // Split shadow into sign bit and other bits.
    Value *SaOtherBits = IRB.CreateLShr(IRB.CreateShl(Sa, 1), 1);
    Value *SaSignBit = IRB.CreateXor(Sa, SaOtherBits);
    // Maximise the undefined shadow bit, minimize other undefined bits.
    return
      IRB.CreateOr(IRB.CreateAnd(A, IRB.CreateNot(SaOtherBits)), SaSignBit);
  } else {
    // Minimize undefined bits.
    return IRB.CreateAnd(A, IRB.CreateNot(Sa));
  }
}

/// Build the highest possible value of V, taking into account V's
///        uninitialized bits.
Value *getHighestPossibleValue(IRBuilder<> &IRB, Value *A, Value *Sa,
                              bool isSigned) {
  if (isSigned) {
    // Split shadow into sign bit and other bits.
    Value *SaOtherBits = IRB.CreateLShr(IRB.CreateShl(Sa, 1), 1);
    Value *SaSignBit = IRB.CreateXor(Sa, SaOtherBits);
    // Minimise the undefined shadow bit, maximise other undefined bits.
    return
      IRB.CreateOr(IRB.CreateAnd(A, IRB.CreateNot(SaSignBit)), SaOtherBits);
  } else {
    // Maximize undefined bits.
    return IRB.CreateOr(A, Sa);
  }
}

/// Instrument relational comparisons.
///
/// This function does exact shadow propagation for all relational
/// comparisons of integers, pointers and vectors of those.
/// FIXME: output seems suboptimal when one of the operands is a constant
void handleRelationalComparisonExact(ICmpInst &I) {
  IRBuilder<> IRB(&I);
  Value *A = I.getOperand(0);
  Value *B = I.getOperand(1);
  Value *Sa = getShadow(A);
  Value *Sb = getShadow(B);

  // Get rid of pointers and vectors of pointers.
  // For ints (and vectors of ints), types of A and Sa match,
  // and this is a no-op.
  A = IRB.CreatePointerCast(A, Sa->getType());
  B = IRB.CreatePointerCast(B, Sb->getType());

  // Let [a0, a1] be the interval of possible values of A, taking into account
  // its undefined bits. Let [b0, b1] be the interval of possible values of B.
  // Then (A cmp B) is defined iff (a0 cmp b1) == (a1 cmp b0).
  bool IsSigned = I.isSigned();
  Value *S1 = IRB.CreateICmp(I.getPredicate(),
                             getLowestPossibleValue(IRB, A, Sa, IsSigned),
                             getHighestPossibleValue(IRB, B, Sb, IsSigned));
  Value *S2 = IRB.CreateICmp(I.getPredicate(),
                             getHighestPossibleValue(IRB, A, Sa, IsSigned),
                             getLowestPossibleValue(IRB, B, Sb, IsSigned));
  Value *Si = IRB.CreateXor(S1, S2);
  setShadow(&I, Si);
  setOriginForNaryOp(I);
}

/// Instrument signed relational comparisons.
///
/// Handle sign bit tests: x<0, x>=0, x<=-1, x>-1 by propagating the highest
/// bit of the shadow. Everything else is delegated to handleShadowOr().
void handleSignedRelationalComparison(ICmpInst &I) {
  Constant *constOp;
  Value *op = nullptr;
  CmpInst::Predicate pre;
  if ((constOp = dyn_cast<Constant>(I.getOperand(1)))) {
    op = I.getOperand(0);
    pre = I.getPredicate();
  } else if ((constOp = dyn_cast<Constant>(I.getOperand(0)))) {
    op = I.getOperand(1);
    pre = I.getSwappedPredicate();
  } else {
    handleShadowOr(I);
    return;
  }

  if ((constOp->isNullValue() &&
       (pre == CmpInst::ICMP_SLT || pre == CmpInst::ICMP_SGE)) ||
      (constOp->isAllOnesValue() &&
       (pre == CmpInst::ICMP_SGT || pre == CmpInst::ICMP_SLE))) {
    IRBuilder<> IRB(&I);
    Value *Shadow = IRB.CreateICmpSLT(getShadow(op), getCleanShadow(op),
                                      "_msprop_icmp_s");
    setShadow(&I, Shadow);
    setOrigin(&I, getOrigin(op));
  } else {
    handleShadowOr(I);
  }
}

void visitICmpInst(ICmpInst &I) {
  if (!ClHandleICmp) {
    handleShadowOr(I);
    return;
  }
  if (I.isEquality()) {
    handleEqualityComparison(I);
    return;
  }

  assert(I.isRelational())((I.isRelational()) ? static_cast<void> (0) : __assert_fail
 ("I.isRelational()", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2352, __PRETTY_FUNCTION__));
  if (ClHandleICmpExact) {
    handleRelationalComparisonExact(I);
    return;
  }
  if (I.isSigned()) {
    handleSignedRelationalComparison(I);
    return;
  }

  assert(I.isUnsigned())((I.isUnsigned()) ? static_cast<void> (0) : __assert_fail
 ("I.isUnsigned()", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2362, __PRETTY_FUNCTION__));
  if ((isa<Constant>(I.getOperand(0)) || isa<Constant>(I.getOperand(1)))) {
    handleRelationalComparisonExact(I);
    return;
  }

  handleShadowOr(I);
}

void visitFCmpInst(FCmpInst &I) {
  handleShadowOr(I);
}

void handleShift(BinaryOperator &I) {
  IRBuilder<> IRB(&I);
  // If any of the S2 bits are poisoned, the whole thing is poisoned.
  // Otherwise perform the same shift on S1.
  Value *S1 = getShadow(&I, 0);
  Value *S2 = getShadow(&I, 1);
  Value *S2Conv = IRB.CreateSExt(IRB.CreateICmpNE(S2, getCleanShadow(S2)),
                                 S2->getType());
  Value *V2 = I.getOperand(1);
  Value *Shift = IRB.CreateBinOp(I.getOpcode(), S1, V2);
  setShadow(&I, IRB.CreateOr(Shift, S2Conv));
  setOriginForNaryOp(I);
}

void visitShl(BinaryOperator &I) { handleShift(I); }
void visitAShr(BinaryOperator &I) { handleShift(I); }
void visitLShr(BinaryOperator &I) { handleShift(I); }

/// Instrument llvm.memmove
///
/// At this point we don't know if llvm.memmove will be inlined or not.
/// If we don't instrument it and it gets inlined,
/// our interceptor will not kick in and we will lose the memmove.
/// If we instrument the call here, but it does not get inlined,
/// we will memove the shadow twice: which is bad in case
/// of overlapping regions. So, we simply lower the intrinsic to a call.
///
/// Similar situation exists for memcpy and memset.
void visitMemMoveInst(MemMoveInst &I) {
  IRBuilder<> IRB(&I);
  IRB.CreateCall(
      MS.MemmoveFn,
      {IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
       IRB.CreatePointerCast(I.getArgOperand(1), IRB.getInt8PtrTy()),
       IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false)});
  I.eraseFromParent();
}

// Similar to memmove: avoid copying shadow twice.
// This is somewhat unfortunate as it may slowdown small constant memcpys.
// FIXME: consider doing manual inline for small constant sizes and proper
// alignment.
void visitMemCpyInst(MemCpyInst &I) {
  IRBuilder<> IRB(&I);
  IRB.CreateCall(
      MS.MemcpyFn,
      {IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
       IRB.CreatePointerCast(I.getArgOperand(1), IRB.getInt8PtrTy()),
       IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false)});
  I.eraseFromParent();
}

// Same as memcpy.
void visitMemSetInst(MemSetInst &I) {
  IRBuilder<> IRB(&I);
  IRB.CreateCall(
      MS.MemsetFn,
      {IRB.CreatePointerCast(I.getArgOperand(0), IRB.getInt8PtrTy()),
       IRB.CreateIntCast(I.getArgOperand(1), IRB.getInt32Ty(), false),
       IRB.CreateIntCast(I.getArgOperand(2), MS.IntptrTy, false)});
  I.eraseFromParent();
}

void visitVAStartInst(VAStartInst &I) {
  VAHelper->visitVAStartInst(I);
}

void visitVACopyInst(VACopyInst &I) {
  VAHelper->visitVACopyInst(I);
}

/// Handle vector store-like intrinsics.
///
/// Instrument intrinsics that look like a simple SIMD store: writes memory,
/// has 1 pointer argument and 1 vector argument, returns void.
bool handleVectorStoreIntrinsic(IntrinsicInst &I) {
  IRBuilder<> IRB(&I);
  Value* Addr = I.getArgOperand(0);
  Value *Shadow = getShadow(&I, 1);
  Value *ShadowPtr, *OriginPtr;

  // We don't know the pointer alignment (could be unaligned SSE store!).
  // Have to assume to worst case.
  std::tie(ShadowPtr, OriginPtr) = getShadowOriginPtr(
      Addr, IRB, Shadow->getType(), Align::None(), /*isStore*/ true);
  IRB.CreateAlignedStore(Shadow, ShadowPtr, 1);

  if (ClCheckAccessAddress)
    insertShadowCheck(Addr, &I);

  // FIXME: factor out common code from materializeStores
  if (MS.TrackOrigins) IRB.CreateStore(getOrigin(&I, 1), OriginPtr);
  return true;
}

/// Handle vector load-like intrinsics.
///
/// Instrument intrinsics that look like a simple SIMD load: reads memory,
/// has 1 pointer argument, returns a vector.
bool handleVectorLoadIntrinsic(IntrinsicInst &I) {
  IRBuilder<> IRB(&I);
  Value *Addr = I.getArgOperand(0);

  Type *ShadowTy = getShadowTy(&I);
  Value *ShadowPtr, *OriginPtr;
9
←
'OriginPtr' declared without an initial value→
  if (PropagateShadow) {
10
←
Assuming field 'PropagateShadow' is false→
11
←
Taking false branch→
    // We don't know the pointer alignment (could be unaligned SSE load!).
    // Have to assume to worst case.
    const Align Alignment = Align::None();
    std::tie(ShadowPtr, OriginPtr) =
        getShadowOriginPtr(Addr, IRB, ShadowTy, Alignment, /*isStore*/ false);
    setShadow(&I, IRB.CreateAlignedLoad(ShadowTy, ShadowPtr,
                                        Alignment.value(), "_msld"));
  } else {
    setShadow(&I, getCleanShadow(&I));
12
←
Calling 'MemorySanitizerVisitor::setShadow'→
18
←
Returning from 'MemorySanitizerVisitor::setShadow'→
  }

  if (ClCheckAccessAddress)
19
←
Assuming the condition is false→
20
←
Taking false branch→
    insertShadowCheck(Addr, &I);

  if (MS.TrackOrigins) {
21
←
Assuming field 'TrackOrigins' is not equal to 0→
22
←
Taking true branch→
    if (PropagateShadow)
23
←
Assuming field 'PropagateShadow' is true→
24
←
Taking true branch→
      setOrigin(&I, IRB.CreateLoad(MS.OriginTy, OriginPtr));
25
←
2nd function call argument is an uninitialized value
    else
      setOrigin(&I, getCleanOrigin());
  }
  return true;
}

/// Handle (SIMD arithmetic)-like intrinsics.
///
/// Instrument intrinsics with any number of arguments of the same type,
/// equal to the return type. The type should be simple (no aggregates or
/// pointers; vectors are fine).
/// Caller guarantees that this intrinsic does not access memory.
bool maybeHandleSimpleNomemIntrinsic(IntrinsicInst &I) {
  Type *RetTy = I.getType();
  if (!(RetTy->isIntOrIntVectorTy() ||
        RetTy->isFPOrFPVectorTy() ||
        RetTy->isX86_MMXTy()))
    return false;

  unsigned NumArgOperands = I.getNumArgOperands();

  for (unsigned i = 0; i < NumArgOperands; ++i) {
    Type *Ty = I.getArgOperand(i)->getType();
    if (Ty != RetTy)
      return false;
  }

  IRBuilder<> IRB(&I);
  ShadowAndOriginCombiner SC(this, IRB);
  for (unsigned i = 0; i < NumArgOperands; ++i)
    SC.Add(I.getArgOperand(i));
  SC.Done(&I);

  return true;
}

/// Heuristically instrument unknown intrinsics.
///
/// The main purpose of this code is to do something reasonable with all
/// random intrinsics we might encounter, most importantly - SIMD intrinsics.
/// We recognize several classes of intrinsics by their argument types and
/// ModRefBehaviour and apply special intrumentation when we are reasonably
/// sure that we know what the intrinsic does.
///
/// We special-case intrinsics where this approach fails. See llvm.bswap
/// handling as an example of that.
bool handleUnknownIntrinsic(IntrinsicInst &I) {
  unsigned NumArgOperands = I.getNumArgOperands();
  if (NumArgOperands == 0)
3
←
Assuming 'NumArgOperands' is not equal to 0→
4
←
Taking false branch→
    return false;

  if (NumArgOperands == 2 &&
5
←
Assuming 'NumArgOperands' is not equal to 2→
      I.getArgOperand(0)->getType()->isPointerTy() &&
      I.getArgOperand(1)->getType()->isVectorTy() &&
      I.getType()->isVoidTy() &&
      !I.onlyReadsMemory()) {
    // This looks like a vector store.
    return handleVectorStoreIntrinsic(I);
  }

  if (NumArgOperands == 1 &&
6
←
Assuming 'NumArgOperands' is equal to 1→
7
←
Taking true branch→
      I.getArgOperand(0)->getType()->isPointerTy() &&
      I.getType()->isVectorTy() &&
      I.onlyReadsMemory()) {
    // This looks like a vector load.
    return handleVectorLoadIntrinsic(I);
8
←
Calling 'MemorySanitizerVisitor::handleVectorLoadIntrinsic'→
  }

  if (I.doesNotAccessMemory())
    if (maybeHandleSimpleNomemIntrinsic(I))
      return true;

  // FIXME: detect and handle SSE maskstore/maskload
  return false;
}

void handleInvariantGroup(IntrinsicInst &I) {
  setShadow(&I, getShadow(&I, 0));
  setOrigin(&I, getOrigin(&I, 0));
}

void handleLifetimeStart(IntrinsicInst &I) {
  if (!PoisonStack)
    return;
  DenseMap<Value *, AllocaInst *> AllocaForValue;
  AllocaInst *AI =
      llvm::findAllocaForValue(I.getArgOperand(1), AllocaForValue);
  if (!AI)
    InstrumentLifetimeStart = false;
  LifetimeStartList.push_back(std::make_pair(&I, AI));
}

void handleBswap(IntrinsicInst &I) {
  IRBuilder<> IRB(&I);
  Value *Op = I.getArgOperand(0);
  Type *OpType = Op->getType();
  Function *BswapFunc = Intrinsic::getDeclaration(
    F.getParent(), Intrinsic::bswap, makeArrayRef(&OpType, 1));
  setShadow(&I, IRB.CreateCall(BswapFunc, getShadow(Op)));
  setOrigin(&I, getOrigin(Op));
}

// Instrument vector convert instrinsic.
//
// This function instruments intrinsics like cvtsi2ss:
// %Out = int_xxx_cvtyyy(%ConvertOp)
// or
// %Out = int_xxx_cvtyyy(%CopyOp, %ConvertOp)
// Intrinsic converts \p NumUsedElements elements of \p ConvertOp to the same
// number \p Out elements, and (if has 2 arguments) copies the rest of the
// elements from \p CopyOp.
// In most cases conversion involves floating-point value which may trigger a
// hardware exception when not fully initialized. For this reason we require
// \p ConvertOp[0:NumUsedElements] to be fully initialized and trap otherwise.
// We copy the shadow of \p CopyOp[NumUsedElements:] to \p
// Out[NumUsedElements:]. This means that intrinsics without \p CopyOp always
// return a fully initialized value.
void handleVectorConvertIntrinsic(IntrinsicInst &I, int NumUsedElements) {
  IRBuilder<> IRB(&I);
  Value *CopyOp, *ConvertOp;

  switch (I.getNumArgOperands()) {
  case 3:
    assert(isa<ConstantInt>(I.getArgOperand(2)) && "Invalid rounding mode")((isa<ConstantInt>(I.getArgOperand(2)) && "Invalid rounding mode"
) ? static_cast<void> (0) : __assert_fail ("isa<ConstantInt>(I.getArgOperand(2)) && \"Invalid rounding mode\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2621, __PRETTY_FUNCTION__));
    LLVM_FALLTHROUGH[[gnu::fallthrough]];
  case 2:
    CopyOp = I.getArgOperand(0);
    ConvertOp = I.getArgOperand(1);
    break;
  case 1:
    ConvertOp = I.getArgOperand(0);
    CopyOp = nullptr;
    break;
  default:
    llvm_unreachable("Cvt intrinsic with unsupported number of arguments.")::llvm::llvm_unreachable_internal("Cvt intrinsic with unsupported number of arguments."
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2632);
  }

  // The first *NumUsedElements* elements of ConvertOp are converted to the
  // same number of output elements. The rest of the output is copied from
  // CopyOp, or (if not available) filled with zeroes.
  // Combine shadow for elements of ConvertOp that are used in this operation,
  // and insert a check.
  // FIXME: consider propagating shadow of ConvertOp, at least in the case of
  // int->any conversion.
  Value *ConvertShadow = getShadow(ConvertOp);
  Value *AggShadow = nullptr;
  if (ConvertOp->getType()->isVectorTy()) {
    AggShadow = IRB.CreateExtractElement(
        ConvertShadow, ConstantInt::get(IRB.getInt32Ty(), 0));
    for (int i = 1; i < NumUsedElements; ++i) {
      Value *MoreShadow = IRB.CreateExtractElement(
          ConvertShadow, ConstantInt::get(IRB.getInt32Ty(), i));
      AggShadow = IRB.CreateOr(AggShadow, MoreShadow);
    }
  } else {
    AggShadow = ConvertShadow;
  }
  assert(AggShadow->getType()->isIntegerTy())((AggShadow->getType()->isIntegerTy()) ? static_cast<
void> (0) : __assert_fail ("AggShadow->getType()->isIntegerTy()"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2655, __PRETTY_FUNCTION__));
  insertShadowCheck(AggShadow, getOrigin(ConvertOp), &I);

  // Build result shadow by zero-filling parts of CopyOp shadow that come from
  // ConvertOp.
  if (CopyOp) {
    assert(CopyOp->getType() == I.getType())((CopyOp->getType() == I.getType()) ? static_cast<void>
 (0) : __assert_fail ("CopyOp->getType() == I.getType()", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2661, __PRETTY_FUNCTION__));
    assert(CopyOp->getType()->isVectorTy())((CopyOp->getType()->isVectorTy()) ? static_cast<void
> (0) : __assert_fail ("CopyOp->getType()->isVectorTy()"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2662, __PRETTY_FUNCTION__));
    Value *ResultShadow = getShadow(CopyOp);
    Type *EltTy = ResultShadow->getType()->getVectorElementType();
    for (int i = 0; i < NumUsedElements; ++i) {
      ResultShadow = IRB.CreateInsertElement(
          ResultShadow, ConstantInt::getNullValue(EltTy),
          ConstantInt::get(IRB.getInt32Ty(), i));
    }
    setShadow(&I, ResultShadow);
    setOrigin(&I, getOrigin(CopyOp));
  } else {
    setShadow(&I, getCleanShadow(&I));
    setOrigin(&I, getCleanOrigin());
  }
}

// Given a scalar or vector, extract lower 64 bits (or less), and return all
// zeroes if it is zero, and all ones otherwise.
Value *Lower64ShadowExtend(IRBuilder<> &IRB, Value *S, Type *T) {
  if (S->getType()->isVectorTy())
    S = CreateShadowCast(IRB, S, IRB.getInt64Ty(), /* Signed */ true);
  assert(S->getType()->getPrimitiveSizeInBits() <= 64)((S->getType()->getPrimitiveSizeInBits() <= 64) ? static_cast
<void> (0) : __assert_fail ("S->getType()->getPrimitiveSizeInBits() <= 64"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2683, __PRETTY_FUNCTION__));
  Value *S2 = IRB.CreateICmpNE(S, getCleanShadow(S));
  return CreateShadowCast(IRB, S2, T, /* Signed */ true);
}

// Given a vector, extract its first element, and return all
// zeroes if it is zero, and all ones otherwise.
Value *LowerElementShadowExtend(IRBuilder<> &IRB, Value *S, Type *T) {
  Value *S1 = IRB.CreateExtractElement(S, (uint64_t)0);
  Value *S2 = IRB.CreateICmpNE(S1, getCleanShadow(S1));
  return CreateShadowCast(IRB, S2, T, /* Signed */ true);
}

Value *VariableShadowExtend(IRBuilder<> &IRB, Value *S) {
  Type *T = S->getType();
  assert(T->isVectorTy())((T->isVectorTy()) ? static_cast<void> (0) : __assert_fail
 ("T->isVectorTy()", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2698, __PRETTY_FUNCTION__));
  Value *S2 = IRB.CreateICmpNE(S, getCleanShadow(S));
  return IRB.CreateSExt(S2, T);
}

// Instrument vector shift instrinsic.
//
// This function instruments intrinsics like int_x86_avx2_psll_w.
// Intrinsic shifts %In by %ShiftSize bits.
// %ShiftSize may be a vector. In that case the lower 64 bits determine shift
// size, and the rest is ignored. Behavior is defined even if shift size is
// greater than register (or field) width.
void handleVectorShiftIntrinsic(IntrinsicInst &I, bool Variable) {
  assert(I.getNumArgOperands() == 2)((I.getNumArgOperands() == 2) ? static_cast<void> (0) :
 __assert_fail ("I.getNumArgOperands() == 2", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2711, __PRETTY_FUNCTION__));
  IRBuilder<> IRB(&I);
  // If any of the S2 bits are poisoned, the whole thing is poisoned.
  // Otherwise perform the same shift on S1.
  Value *S1 = getShadow(&I, 0);
  Value *S2 = getShadow(&I, 1);
  Value *S2Conv = Variable ? VariableShadowExtend(IRB, S2)
                           : Lower64ShadowExtend(IRB, S2, getShadowTy(&I));
  Value *V1 = I.getOperand(0);
  Value *V2 = I.getOperand(1);
  Value *Shift = IRB.CreateCall(I.getFunctionType(), I.getCalledValue(),
                                {IRB.CreateBitCast(S1, V1->getType()), V2});
  Shift = IRB.CreateBitCast(Shift, getShadowTy(&I));
  setShadow(&I, IRB.CreateOr(Shift, S2Conv));
  setOriginForNaryOp(I);
}

// Get an X86_MMX-sized vector type.
Type *getMMXVectorTy(unsigned EltSizeInBits) {
  const unsigned X86_MMXSizeInBits = 64;
  assert(EltSizeInBits != 0 && (X86_MMXSizeInBits % EltSizeInBits) == 0 &&((EltSizeInBits != 0 && (X86_MMXSizeInBits % EltSizeInBits
) == 0 && "Illegal MMX vector element size") ? static_cast
<void> (0) : __assert_fail ("EltSizeInBits != 0 && (X86_MMXSizeInBits % EltSizeInBits) == 0 && \"Illegal MMX vector element size\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2732, __PRETTY_FUNCTION__))
         "Illegal MMX vector element size")((EltSizeInBits != 0 && (X86_MMXSizeInBits % EltSizeInBits
) == 0 && "Illegal MMX vector element size") ? static_cast
<void> (0) : __assert_fail ("EltSizeInBits != 0 && (X86_MMXSizeInBits % EltSizeInBits) == 0 && \"Illegal MMX vector element size\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2732, __PRETTY_FUNCTION__));
  return VectorType::get(IntegerType::get(*MS.C, EltSizeInBits),
                         X86_MMXSizeInBits / EltSizeInBits);
}

// Returns a signed counterpart for an (un)signed-saturate-and-pack
// intrinsic.
Intrinsic::ID getSignedPackIntrinsic(Intrinsic::ID id) {
  switch (id) {
    case Intrinsic::x86_sse2_packsswb_128:
    case Intrinsic::x86_sse2_packuswb_128:
      return Intrinsic::x86_sse2_packsswb_128;

    case Intrinsic::x86_sse2_packssdw_128:
    case Intrinsic::x86_sse41_packusdw:
      return Intrinsic::x86_sse2_packssdw_128;

    case Intrinsic::x86_avx2_packsswb:
    case Intrinsic::x86_avx2_packuswb:
      return Intrinsic::x86_avx2_packsswb;

    case Intrinsic::x86_avx2_packssdw:
    case Intrinsic::x86_avx2_packusdw:
      return Intrinsic::x86_avx2_packssdw;

    case Intrinsic::x86_mmx_packsswb:
    case Intrinsic::x86_mmx_packuswb:
      return Intrinsic::x86_mmx_packsswb;

    case Intrinsic::x86_mmx_packssdw:
      return Intrinsic::x86_mmx_packssdw;
    default:
      llvm_unreachable("unexpected intrinsic id")::llvm::llvm_unreachable_internal("unexpected intrinsic id", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2764);
  }
}

// Instrument vector pack instrinsic.
//
// This function instruments intrinsics like x86_mmx_packsswb, that
// packs elements of 2 input vectors into half as many bits with saturation.
// Shadow is propagated with the signed variant of the same intrinsic applied
// to sext(Sa != zeroinitializer), sext(Sb != zeroinitializer).
// EltSizeInBits is used only for x86mmx arguments.
void handleVectorPackIntrinsic(IntrinsicInst &I, unsigned EltSizeInBits = 0) {
  assert(I.getNumArgOperands() == 2)((I.getNumArgOperands() == 2) ? static_cast<void> (0) :
 __assert_fail ("I.getNumArgOperands() == 2", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2776, __PRETTY_FUNCTION__));
  bool isX86_MMX = I.getOperand(0)->getType()->isX86_MMXTy();
  IRBuilder<> IRB(&I);
  Value *S1 = getShadow(&I, 0);
  Value *S2 = getShadow(&I, 1);
  assert(isX86_MMX || S1->getType()->isVectorTy())((isX86_MMX || S1->getType()->isVectorTy()) ? static_cast
<void> (0) : __assert_fail ("isX86_MMX || S1->getType()->isVectorTy()"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 2781, __PRETTY_FUNCTION__));

  // SExt and ICmpNE below must apply to individual elements of input vectors.
  // In case of x86mmx arguments, cast them to appropriate vector types and
  // back.
  Type *T = isX86_MMX ? getMMXVectorTy(EltSizeInBits) : S1->getType();
  if (isX86_MMX) {
    S1 = IRB.CreateBitCast(S1, T);
    S2 = IRB.CreateBitCast(S2, T);
  }
  Value *S1_ext = IRB.CreateSExt(
      IRB.CreateICmpNE(S1, Constant::getNullValue(T)), T);
  Value *S2_ext = IRB.CreateSExt(
      IRB.CreateICmpNE(S2, Constant::getNullValue(T)), T);
  if (isX86_MMX) {
    Type *X86_MMXTy = Type::getX86_MMXTy(*MS.C);
    S1_ext = IRB.CreateBitCast(S1_ext, X86_MMXTy);
    S2_ext = IRB.CreateBitCast(S2_ext, X86_MMXTy);
  }

  Function *ShadowFn = Intrinsic::getDeclaration(
      F.getParent(), getSignedPackIntrinsic(I.getIntrinsicID()));

  Value *S =
      IRB.CreateCall(ShadowFn, {S1_ext, S2_ext}, "_msprop_vector_pack");
  if (isX86_MMX) S = IRB.CreateBitCast(S, getShadowTy(&I));
  setShadow(&I, S);
  setOriginForNaryOp(I);
}

// Instrument sum-of-absolute-differencies intrinsic.
void handleVectorSadIntrinsic(IntrinsicInst &I) {
  const unsigned SignificantBitsPerResultElement = 16;
  bool isX86_MMX = I.getOperand(0)->getType()->isX86_MMXTy();
  Type *ResTy = isX86_MMX ? IntegerType::get(*MS.C, 64) : I.getType();
  unsigned ZeroBitsPerResultElement =
      ResTy->getScalarSizeInBits() - SignificantBitsPerResultElement;

  IRBuilder<> IRB(&I);
  Value *S = IRB.CreateOr(getShadow(&I, 0), getShadow(&I, 1));
  S = IRB.CreateBitCast(S, ResTy);
  S = IRB.CreateSExt(IRB.CreateICmpNE(S, Constant::getNullValue(ResTy)),
                     ResTy);
  S = IRB.CreateLShr(S, ZeroBitsPerResultElement);
  S = IRB.CreateBitCast(S, getShadowTy(&I));
  setShadow(&I, S);
  setOriginForNaryOp(I);
}

// Instrument multiply-add intrinsic.
void handleVectorPmaddIntrinsic(IntrinsicInst &I,
                                unsigned EltSizeInBits = 0) {
  bool isX86_MMX = I.getOperand(0)->getType()->isX86_MMXTy();
  Type *ResTy = isX86_MMX ? getMMXVectorTy(EltSizeInBits * 2) : I.getType();
  IRBuilder<> IRB(&I);
  Value *S = IRB.CreateOr(getShadow(&I, 0), getShadow(&I, 1));
  S = IRB.CreateBitCast(S, ResTy);
  S = IRB.CreateSExt(IRB.CreateICmpNE(S, Constant::getNullValue(ResTy)),
                     ResTy);
  S = IRB.CreateBitCast(S, getShadowTy(&I));
  setShadow(&I, S);
  setOriginForNaryOp(I);
}

// Instrument compare-packed intrinsic.
// Basically, an or followed by sext(icmp ne 0) to end up with all-zeros or
// all-ones shadow.
void handleVectorComparePackedIntrinsic(IntrinsicInst &I) {
  IRBuilder<> IRB(&I);
  Type *ResTy = getShadowTy(&I);
  Value *S0 = IRB.CreateOr(getShadow(&I, 0), getShadow(&I, 1));
  Value *S = IRB.CreateSExt(
      IRB.CreateICmpNE(S0, Constant::getNullValue(ResTy)), ResTy);
  setShadow(&I, S);
  setOriginForNaryOp(I);
}

// Instrument compare-scalar intrinsic.
// This handles both cmp* intrinsics which return the result in the first
// element of a vector, and comi* which return the result as i32.
void handleVectorCompareScalarIntrinsic(IntrinsicInst &I) {
  IRBuilder<> IRB(&I);
  Value *S0 = IRB.CreateOr(getShadow(&I, 0), getShadow(&I, 1));
  Value *S = LowerElementShadowExtend(IRB, S0, getShadowTy(&I));
  setShadow(&I, S);
  setOriginForNaryOp(I);
}

void handleStmxcsr(IntrinsicInst &I) {
  IRBuilder<> IRB(&I);
  Value* Addr = I.getArgOperand(0);
  Type *Ty = IRB.getInt32Ty();
  Value *ShadowPtr =
      getShadowOriginPtr(Addr, IRB, Ty, Align::None(), /*isStore*/ true)
          .first;

  IRB.CreateStore(getCleanShadow(Ty),
                  IRB.CreatePointerCast(ShadowPtr, Ty->getPointerTo()));

  if (ClCheckAccessAddress)
    insertShadowCheck(Addr, &I);
}

void handleLdmxcsr(IntrinsicInst &I) {
  if (!InsertChecks) return;

  IRBuilder<> IRB(&I);
  Value *Addr = I.getArgOperand(0);
  Type *Ty = IRB.getInt32Ty();
  const Align Alignment = Align::None();
  Value *ShadowPtr, *OriginPtr;
  std::tie(ShadowPtr, OriginPtr) =
      getShadowOriginPtr(Addr, IRB, Ty, Alignment, /*isStore*/ false);

  if (ClCheckAccessAddress)
    insertShadowCheck(Addr, &I);

  Value *Shadow =
      IRB.CreateAlignedLoad(Ty, ShadowPtr, Alignment.value(), "_ldmxcsr");
  Value *Origin = MS.TrackOrigins ? IRB.CreateLoad(MS.OriginTy, OriginPtr)
                                  : getCleanOrigin();
  insertShadowCheck(Shadow, Origin, &I);
}

void handleMaskedStore(IntrinsicInst &I) {
  IRBuilder<> IRB(&I);
  Value *V = I.getArgOperand(0);
  Value *Addr = I.getArgOperand(1);
  const MaybeAlign Alignment(
      cast<ConstantInt>(I.getArgOperand(2))->getZExtValue());
  Value *Mask = I.getArgOperand(3);
  Value *Shadow = getShadow(V);

  Value *ShadowPtr;
  Value *OriginPtr;
  std::tie(ShadowPtr, OriginPtr) = getShadowOriginPtr(
      Addr, IRB, Shadow->getType(), Alignment, /*isStore*/ true);

  if (ClCheckAccessAddress) {
    insertShadowCheck(Addr, &I);
    // Uninitialized mask is kind of like uninitialized address, but not as
    // scary.
    insertShadowCheck(Mask, &I);
  }

  IRB.CreateMaskedStore(Shadow, ShadowPtr, Alignment ? Alignment->value() : 0,
                        Mask);

  if (MS.TrackOrigins) {
    auto &DL = F.getParent()->getDataLayout();
    paintOrigin(IRB, getOrigin(V), OriginPtr,
                DL.getTypeStoreSize(Shadow->getType()),
                llvm::max(Alignment, kMinOriginAlignment));
  }
}

bool handleMaskedLoad(IntrinsicInst &I) {
  IRBuilder<> IRB(&I);
  Value *Addr = I.getArgOperand(0);
  const MaybeAlign Alignment(
      cast<ConstantInt>(I.getArgOperand(1))->getZExtValue());
  Value *Mask = I.getArgOperand(2);
  Value *PassThru = I.getArgOperand(3);

  Type *ShadowTy = getShadowTy(&I);
  Value *ShadowPtr, *OriginPtr;
  if (PropagateShadow) {
    std::tie(ShadowPtr, OriginPtr) =
        getShadowOriginPtr(Addr, IRB, ShadowTy, Alignment, /*isStore*/ false);
    setShadow(&I, IRB.CreateMaskedLoad(
                      ShadowPtr, Alignment ? Alignment->value() : 0, Mask,
                      getShadow(PassThru), "_msmaskedld"));
  } else {
    setShadow(&I, getCleanShadow(&I));
  }

  if (ClCheckAccessAddress) {
    insertShadowCheck(Addr, &I);
    insertShadowCheck(Mask, &I);
  }

  if (MS.TrackOrigins) {
    if (PropagateShadow) {
      // Choose between PassThru's and the loaded value's origins.
      Value *MaskedPassThruShadow = IRB.CreateAnd(
          getShadow(PassThru), IRB.CreateSExt(IRB.CreateNeg(Mask), ShadowTy));

      Value *Acc = IRB.CreateExtractElement(
          MaskedPassThruShadow, ConstantInt::get(IRB.getInt32Ty(), 0));
      for (int i = 1, N = PassThru->getType()->getVectorNumElements(); i < N;
           ++i) {
        Value *More = IRB.CreateExtractElement(
            MaskedPassThruShadow, ConstantInt::get(IRB.getInt32Ty(), i));
        Acc = IRB.CreateOr(Acc, More);
      }

      Value *Origin = IRB.CreateSelect(
          IRB.CreateICmpNE(Acc, Constant::getNullValue(Acc->getType())),
          getOrigin(PassThru), IRB.CreateLoad(MS.OriginTy, OriginPtr));

      setOrigin(&I, Origin);
    } else {
      setOrigin(&I, getCleanOrigin());
    }
  }
  return true;
}

// Instrument BMI / BMI2 intrinsics.
// All of these intrinsics are Z = I(X, Y)
// where the types of all operands and the result match, and are either i32 or i64.
// The following instrumentation happens to work for all of them:
//   Sz = I(Sx, Y) | (sext (Sy != 0))
void handleBmiIntrinsic(IntrinsicInst &I) {
  IRBuilder<> IRB(&I);
  Type *ShadowTy = getShadowTy(&I);

  // If any bit of the mask operand is poisoned, then the whole thing is.
  Value *SMask = getShadow(&I, 1);
  SMask = IRB.CreateSExt(IRB.CreateICmpNE(SMask, getCleanShadow(ShadowTy)),
                         ShadowTy);
  // Apply the same intrinsic to the shadow of the first operand.
  Value *S = IRB.CreateCall(I.getCalledFunction(),
                            {getShadow(&I, 0), I.getOperand(1)});
  S = IRB.CreateOr(SMask, S);
  setShadow(&I, S);
  setOriginForNaryOp(I);
}

void visitIntrinsicInst(IntrinsicInst &I) {
  switch (I.getIntrinsicID()) {
1
Control jumps to the 'default' case at line 3249→
  case Intrinsic::lifetime_start:
    handleLifetimeStart(I);
    break;
  case Intrinsic::launder_invariant_group:
  case Intrinsic::strip_invariant_group:
    handleInvariantGroup(I);
    break;
  case Intrinsic::bswap:
    handleBswap(I);
    break;
  case Intrinsic::masked_store:
    handleMaskedStore(I);
    break;
  case Intrinsic::masked_load:
    handleMaskedLoad(I);
    break;
  case Intrinsic::x86_sse_stmxcsr:
    handleStmxcsr(I);
    break;
  case Intrinsic::x86_sse_ldmxcsr:
    handleLdmxcsr(I);
    break;
  case Intrinsic::x86_avx512_vcvtsd2usi64:
  case Intrinsic::x86_avx512_vcvtsd2usi32:
  case Intrinsic::x86_avx512_vcvtss2usi64:
  case Intrinsic::x86_avx512_vcvtss2usi32:
  case Intrinsic::x86_avx512_cvttss2usi64:
  case Intrinsic::x86_avx512_cvttss2usi:
  case Intrinsic::x86_avx512_cvttsd2usi64:
  case Intrinsic::x86_avx512_cvttsd2usi:
  case Intrinsic::x86_avx512_cvtusi2ss:
  case Intrinsic::x86_avx512_cvtusi642sd:
  case Intrinsic::x86_avx512_cvtusi642ss:
  case Intrinsic::x86_sse2_cvtsd2si64:
  case Intrinsic::x86_sse2_cvtsd2si:
  case Intrinsic::x86_sse2_cvtsd2ss:
  case Intrinsic::x86_sse2_cvttsd2si64:
  case Intrinsic::x86_sse2_cvttsd2si:
  case Intrinsic::x86_sse_cvtss2si64:
  case Intrinsic::x86_sse_cvtss2si:
  case Intrinsic::x86_sse_cvttss2si64:
  case Intrinsic::x86_sse_cvttss2si:
    handleVectorConvertIntrinsic(I, 1);
    break;
  case Intrinsic::x86_sse_cvtps2pi:
  case Intrinsic::x86_sse_cvttps2pi:
    handleVectorConvertIntrinsic(I, 2);
    break;

  case Intrinsic::x86_avx512_psll_w_512:
  case Intrinsic::x86_avx512_psll_d_512:
  case Intrinsic::x86_avx512_psll_q_512:
  case Intrinsic::x86_avx512_pslli_w_512:
  case Intrinsic::x86_avx512_pslli_d_512:
  case Intrinsic::x86_avx512_pslli_q_512:
  case Intrinsic::x86_avx512_psrl_w_512:
  case Intrinsic::x86_avx512_psrl_d_512:
  case Intrinsic::x86_avx512_psrl_q_512:
  case Intrinsic::x86_avx512_psra_w_512:
  case Intrinsic::x86_avx512_psra_d_512:
  case Intrinsic::x86_avx512_psra_q_512:
  case Intrinsic::x86_avx512_psrli_w_512:
  case Intrinsic::x86_avx512_psrli_d_512:
  case Intrinsic::x86_avx512_psrli_q_512:
  case Intrinsic::x86_avx512_psrai_w_512:
  case Intrinsic::x86_avx512_psrai_d_512:
  case Intrinsic::x86_avx512_psrai_q_512:
  case Intrinsic::x86_avx512_psra_q_256:
  case Intrinsic::x86_avx512_psra_q_128:
  case Intrinsic::x86_avx512_psrai_q_256:
  case Intrinsic::x86_avx512_psrai_q_128:
  case Intrinsic::x86_avx2_psll_w:
  case Intrinsic::x86_avx2_psll_d:
  case Intrinsic::x86_avx2_psll_q:
  case Intrinsic::x86_avx2_pslli_w:
  case Intrinsic::x86_avx2_pslli_d:
  case Intrinsic::x86_avx2_pslli_q:
  case Intrinsic::x86_avx2_psrl_w:
  case Intrinsic::x86_avx2_psrl_d:
  case Intrinsic::x86_avx2_psrl_q:
  case Intrinsic::x86_avx2_psra_w:
  case Intrinsic::x86_avx2_psra_d:
  case Intrinsic::x86_avx2_psrli_w:
  case Intrinsic::x86_avx2_psrli_d:
  case Intrinsic::x86_avx2_psrli_q:
  case Intrinsic::x86_avx2_psrai_w:
  case Intrinsic::x86_avx2_psrai_d:
  case Intrinsic::x86_sse2_psll_w:
  case Intrinsic::x86_sse2_psll_d:
  case Intrinsic::x86_sse2_psll_q:
  case Intrinsic::x86_sse2_pslli_w:
  case Intrinsic::x86_sse2_pslli_d:
  case Intrinsic::x86_sse2_pslli_q:
  case Intrinsic::x86_sse2_psrl_w:
  case Intrinsic::x86_sse2_psrl_d:
  case Intrinsic::x86_sse2_psrl_q:
  case Intrinsic::x86_sse2_psra_w:
  case Intrinsic::x86_sse2_psra_d:
  case Intrinsic::x86_sse2_psrli_w:
  case Intrinsic::x86_sse2_psrli_d:
  case Intrinsic::x86_sse2_psrli_q:
  case Intrinsic::x86_sse2_psrai_w:
  case Intrinsic::x86_sse2_psrai_d:
  case Intrinsic::x86_mmx_psll_w:
  case Intrinsic::x86_mmx_psll_d:
  case Intrinsic::x86_mmx_psll_q:
  case Intrinsic::x86_mmx_pslli_w:
  case Intrinsic::x86_mmx_pslli_d:
  case Intrinsic::x86_mmx_pslli_q:
  case Intrinsic::x86_mmx_psrl_w:
  case Intrinsic::x86_mmx_psrl_d:
  case Intrinsic::x86_mmx_psrl_q:
  case Intrinsic::x86_mmx_psra_w:
  case Intrinsic::x86_mmx_psra_d:
  case Intrinsic::x86_mmx_psrli_w:
  case Intrinsic::x86_mmx_psrli_d:
  case Intrinsic::x86_mmx_psrli_q:
  case Intrinsic::x86_mmx_psrai_w:
  case Intrinsic::x86_mmx_psrai_d:
    handleVectorShiftIntrinsic(I, /* Variable */ false);
    break;
  case Intrinsic::x86_avx2_psllv_d:
  case Intrinsic::x86_avx2_psllv_d_256:
  case Intrinsic::x86_avx512_psllv_d_512:
  case Intrinsic::x86_avx2_psllv_q:
  case Intrinsic::x86_avx2_psllv_q_256:
  case Intrinsic::x86_avx512_psllv_q_512:
  case Intrinsic::x86_avx2_psrlv_d:
  case Intrinsic::x86_avx2_psrlv_d_256:
  case Intrinsic::x86_avx512_psrlv_d_512:
  case Intrinsic::x86_avx2_psrlv_q:
  case Intrinsic::x86_avx2_psrlv_q_256:
  case Intrinsic::x86_avx512_psrlv_q_512:
  case Intrinsic::x86_avx2_psrav_d:
  case Intrinsic::x86_avx2_psrav_d_256:
  case Intrinsic::x86_avx512_psrav_d_512:
  case Intrinsic::x86_avx512_psrav_q_128:
  case Intrinsic::x86_avx512_psrav_q_256:
  case Intrinsic::x86_avx512_psrav_q_512:
    handleVectorShiftIntrinsic(I, /* Variable */ true);
    break;

  case Intrinsic::x86_sse2_packsswb_128:
  case Intrinsic::x86_sse2_packssdw_128:
  case Intrinsic::x86_sse2_packuswb_128:
  case Intrinsic::x86_sse41_packusdw:
  case Intrinsic::x86_avx2_packsswb:
  case Intrinsic::x86_avx2_packssdw:
  case Intrinsic::x86_avx2_packuswb:
  case Intrinsic::x86_avx2_packusdw:
    handleVectorPackIntrinsic(I);
    break;

  case Intrinsic::x86_mmx_packsswb:
  case Intrinsic::x86_mmx_packuswb:
    handleVectorPackIntrinsic(I, 16);
    break;

  case Intrinsic::x86_mmx_packssdw:
    handleVectorPackIntrinsic(I, 32);
    break;

  case Intrinsic::x86_mmx_psad_bw:
  case Intrinsic::x86_sse2_psad_bw:
  case Intrinsic::x86_avx2_psad_bw:
    handleVectorSadIntrinsic(I);
    break;

  case Intrinsic::x86_sse2_pmadd_wd:
  case Intrinsic::x86_avx2_pmadd_wd:
  case Intrinsic::x86_ssse3_pmadd_ub_sw_128:
  case Intrinsic::x86_avx2_pmadd_ub_sw:
    handleVectorPmaddIntrinsic(I);
    break;

  case Intrinsic::x86_ssse3_pmadd_ub_sw:
    handleVectorPmaddIntrinsic(I, 8);
    break;

  case Intrinsic::x86_mmx_pmadd_wd:
    handleVectorPmaddIntrinsic(I, 16);
    break;

  case Intrinsic::x86_sse_cmp_ss:
  case Intrinsic::x86_sse2_cmp_sd:
  case Intrinsic::x86_sse_comieq_ss:
  case Intrinsic::x86_sse_comilt_ss:
  case Intrinsic::x86_sse_comile_ss:
  case Intrinsic::x86_sse_comigt_ss:
  case Intrinsic::x86_sse_comige_ss:
  case Intrinsic::x86_sse_comineq_ss:
  case Intrinsic::x86_sse_ucomieq_ss:
  case Intrinsic::x86_sse_ucomilt_ss:
  case Intrinsic::x86_sse_ucomile_ss:
  case Intrinsic::x86_sse_ucomigt_ss:
  case Intrinsic::x86_sse_ucomige_ss:
  case Intrinsic::x86_sse_ucomineq_ss:
  case Intrinsic::x86_sse2_comieq_sd:
  case Intrinsic::x86_sse2_comilt_sd:
  case Intrinsic::x86_sse2_comile_sd:
  case Intrinsic::x86_sse2_comigt_sd:
  case Intrinsic::x86_sse2_comige_sd:
  case Intrinsic::x86_sse2_comineq_sd:
  case Intrinsic::x86_sse2_ucomieq_sd:
  case Intrinsic::x86_sse2_ucomilt_sd:
  case Intrinsic::x86_sse2_ucomile_sd:
  case Intrinsic::x86_sse2_ucomigt_sd:
  case Intrinsic::x86_sse2_ucomige_sd:
  case Intrinsic::x86_sse2_ucomineq_sd:
    handleVectorCompareScalarIntrinsic(I);
    break;

  case Intrinsic::x86_sse_cmp_ps:
  case Intrinsic::x86_sse2_cmp_pd:
    // FIXME: For x86_avx_cmp_pd_256 and x86_avx_cmp_ps_256 this function
    // generates reasonably looking IR that fails in the backend with "Do not
    // know how to split the result of this operator!".
    handleVectorComparePackedIntrinsic(I);
    break;

  case Intrinsic::x86_bmi_bextr_32:
  case Intrinsic::x86_bmi_bextr_64:
  case Intrinsic::x86_bmi_bzhi_32:
  case Intrinsic::x86_bmi_bzhi_64:
  case Intrinsic::x86_bmi_pdep_32:
  case Intrinsic::x86_bmi_pdep_64:
  case Intrinsic::x86_bmi_pext_32:
  case Intrinsic::x86_bmi_pext_64:
    handleBmiIntrinsic(I);
    break;

  case Intrinsic::is_constant:
    // The result of llvm.is.constant() is always defined.
    setShadow(&I, getCleanShadow(&I));
    setOrigin(&I, getCleanOrigin());
    break;

  default:
    if (!handleUnknownIntrinsic(I))
2
←
Calling 'MemorySanitizerVisitor::handleUnknownIntrinsic'→
      visitInstruction(I);
    break;
  }
}

void visitCallSite(CallSite CS) {
  Instruction &I = *CS.getInstruction();
  assert(!I.getMetadata("nosanitize"))((!I.getMetadata("nosanitize")) ? static_cast<void> (0)
 : __assert_fail ("!I.getMetadata(\"nosanitize\")", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3258, __PRETTY_FUNCTION__));
  assert((CS.isCall() || CS.isInvoke() || CS.isCallBr()) &&(((CS.isCall() || CS.isInvoke() || CS.isCallBr()) && "Unknown type of CallSite"
) ? static_cast<void> (0) : __assert_fail ("(CS.isCall() || CS.isInvoke() || CS.isCallBr()) && \"Unknown type of CallSite\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3260, __PRETTY_FUNCTION__))
         "Unknown type of CallSite")(((CS.isCall() || CS.isInvoke() || CS.isCallBr()) && "Unknown type of CallSite"
) ? static_cast<void> (0) : __assert_fail ("(CS.isCall() || CS.isInvoke() || CS.isCallBr()) && \"Unknown type of CallSite\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3260, __PRETTY_FUNCTION__));
  if (CS.isCallBr() || (CS.isCall() && cast<CallInst>(&I)->isInlineAsm())) {
    // For inline asm (either a call to asm function, or callbr instruction),
    // do the usual thing: check argument shadow and mark all outputs as
    // clean. Note that any side effects of the inline asm that are not
    // immediately visible in its constraints are not handled.
    if (ClHandleAsmConservative && MS.CompileKernel)
      visitAsmInstruction(I);
    else
      visitInstruction(I);
    return;
  }
  if (CS.isCall()) {
    CallInst *Call = cast<CallInst>(&I);
    assert(!isa<IntrinsicInst>(&I) && "intrinsics are handled elsewhere")((!isa<IntrinsicInst>(&I) && "intrinsics are handled elsewhere"
) ? static_cast<void> (0) : __assert_fail ("!isa<IntrinsicInst>(&I) && \"intrinsics are handled elsewhere\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3274, __PRETTY_FUNCTION__));

    // We are going to insert code that relies on the fact that the callee
    // will become a non-readonly function after it is instrumented by us. To
    // prevent this code from being optimized out, mark that function
    // non-readonly in advance.
    if (Function *Func = Call->getCalledFunction()) {
      // Clear out readonly/readnone attributes.
      AttrBuilder B;
      B.addAttribute(Attribute::ReadOnly)
          .addAttribute(Attribute::ReadNone)
          .addAttribute(Attribute::WriteOnly)
          .addAttribute(Attribute::ArgMemOnly)
          .addAttribute(Attribute::Speculatable);
      Func->removeAttributes(AttributeList::FunctionIndex, B);
    }

    maybeMarkSanitizerLibraryCallNoBuiltin(Call, TLI);
  }
  IRBuilder<> IRB(&I);

  unsigned ArgOffset = 0;
  LLVM_DEBUG(dbgs() << "  CallSite: " << I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "  CallSite: " << I <<
 "\n"; } } while (false);
  for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End = CS.arg_end();
       ArgIt != End; ++ArgIt) {
    Value *A = *ArgIt;
    unsigned i = ArgIt - CS.arg_begin();
    if (!A->getType()->isSized()) {
      LLVM_DEBUG(dbgs() << "Arg " << i << " is not sized: " << I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "Arg " << i << " is not sized: "
 << I << "\n"; } } while (false);
      continue;
    }
    unsigned Size = 0;
    Value *Store = nullptr;
    // Compute the Shadow for arg even if it is ByVal, because
    // in that case getShadow() will copy the actual arg shadow to
    // __msan_param_tls.
    Value *ArgShadow = getShadow(A);
    Value *ArgShadowBase = getShadowPtrForArgument(A, IRB, ArgOffset);
    LLVM_DEBUG(dbgs() << "  Arg#" << i << ": " << *Ado { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "  Arg#" << i << ": "
 << *A << " Shadow: " << *ArgShadow <<
 "\n"; } } while (false)
                      << " Shadow: " << *ArgShadow << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "  Arg#" << i << ": "
 << *A << " Shadow: " << *ArgShadow <<
 "\n"; } } while (false);
    bool ArgIsInitialized = false;
    const DataLayout &DL = F.getParent()->getDataLayout();
    if (CS.paramHasAttr(i, Attribute::ByVal)) {
      assert(A->getType()->isPointerTy() &&((A->getType()->isPointerTy() && "ByVal argument is not a pointer!"
) ? static_cast<void> (0) : __assert_fail ("A->getType()->isPointerTy() && \"ByVal argument is not a pointer!\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3318, __PRETTY_FUNCTION__))
             "ByVal argument is not a pointer!")((A->getType()->isPointerTy() && "ByVal argument is not a pointer!"
) ? static_cast<void> (0) : __assert_fail ("A->getType()->isPointerTy() && \"ByVal argument is not a pointer!\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3318, __PRETTY_FUNCTION__));
      Size = DL.getTypeAllocSize(A->getType()->getPointerElementType());
      if (ArgOffset + Size > kParamTLSSize) break;
      const MaybeAlign ParamAlignment(CS.getParamAlignment(i));
      MaybeAlign Alignment = llvm::None;
      if (ParamAlignment)
        Alignment = std::min(*ParamAlignment, kShadowTLSAlignment);
      Value *AShadowPtr =
          getShadowOriginPtr(A, IRB, IRB.getInt8Ty(), Alignment,
                             /*isStore*/ false)
              .first;

      Store = IRB.CreateMemCpy(ArgShadowBase, Alignment, AShadowPtr,
                               Alignment, Size);
      // TODO(glider): need to copy origins.
    } else {
      Size = DL.getTypeAllocSize(A->getType());
      if (ArgOffset + Size > kParamTLSSize) break;
      Store = IRB.CreateAlignedStore(ArgShadow, ArgShadowBase,
                                     kShadowTLSAlignment.value());
      Constant *Cst = dyn_cast<Constant>(ArgShadow);
      if (Cst && Cst->isNullValue()) ArgIsInitialized = true;
    }
    if (MS.TrackOrigins && !ArgIsInitialized)
      IRB.CreateStore(getOrigin(A),
                      getOriginPtrForArgument(A, IRB, ArgOffset));
    (void)Store;
    assert(Size != 0 && Store != nullptr)((Size != 0 && Store != nullptr) ? static_cast<void
> (0) : __assert_fail ("Size != 0 && Store != nullptr"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3345, __PRETTY_FUNCTION__));
    LLVM_DEBUG(dbgs() << "  Param:" << *Store << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "  Param:" << *Store <<
 "\n"; } } while (false);
    ArgOffset += alignTo(Size, 8);
  }
  LLVM_DEBUG(dbgs() << "  done with call args\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "  done with call args\n"; } } while
 (false);

  FunctionType *FT = CS.getFunctionType();
  if (FT->isVarArg()) {
    VAHelper->visitCallSite(CS, IRB);
  }

  // Now, get the shadow for the RetVal.
  if (!I.getType()->isSized()) return;
  // Don't emit the epilogue for musttail call returns.
  if (CS.isCall() && cast<CallInst>(&I)->isMustTailCall()) return;
  IRBuilder<> IRBBefore(&I);
  // Until we have full dynamic coverage, make sure the retval shadow is 0.
  Value *Base = getShadowPtrForRetval(&I, IRBBefore);
  IRBBefore.CreateAlignedStore(getCleanShadow(&I), Base,
                               kShadowTLSAlignment.value());
  BasicBlock::iterator NextInsn;
  if (CS.isCall()) {
    NextInsn = ++I.getIterator();
    assert(NextInsn != I.getParent()->end())((NextInsn != I.getParent()->end()) ? static_cast<void>
 (0) : __assert_fail ("NextInsn != I.getParent()->end()", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3368, __PRETTY_FUNCTION__));
  } else {
    BasicBlock *NormalDest = cast<InvokeInst>(&I)->getNormalDest();
    if (!NormalDest->getSinglePredecessor()) {
      // FIXME: this case is tricky, so we are just conservative here.
      // Perhaps we need to split the edge between this BB and NormalDest,
      // but a naive attempt to use SplitEdge leads to a crash.
      setShadow(&I, getCleanShadow(&I));
      setOrigin(&I, getCleanOrigin());
      return;
    }
    // FIXME: NextInsn is likely in a basic block that has not been visited yet.
    // Anything inserted there will be instrumented by MSan later!
    NextInsn = NormalDest->getFirstInsertionPt();
    assert(NextInsn != NormalDest->end() &&((NextInsn != NormalDest->end() && "Could not find insertion point for retval shadow load"
) ? static_cast<void> (0) : __assert_fail ("NextInsn != NormalDest->end() && \"Could not find insertion point for retval shadow load\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3383, __PRETTY_FUNCTION__))
           "Could not find insertion point for retval shadow load")((NextInsn != NormalDest->end() && "Could not find insertion point for retval shadow load"
) ? static_cast<void> (0) : __assert_fail ("NextInsn != NormalDest->end() && \"Could not find insertion point for retval shadow load\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3383, __PRETTY_FUNCTION__));
  }
  IRBuilder<> IRBAfter(&*NextInsn);
  Value *RetvalShadow = IRBAfter.CreateAlignedLoad(
      getShadowTy(&I), getShadowPtrForRetval(&I, IRBAfter),
      kShadowTLSAlignment.value(), "_msret");
  setShadow(&I, RetvalShadow);
  if (MS.TrackOrigins)
    setOrigin(&I, IRBAfter.CreateLoad(MS.OriginTy,
                                      getOriginPtrForRetval(IRBAfter)));
}

bool isAMustTailRetVal(Value *RetVal) {
  if (auto *I = dyn_cast<BitCastInst>(RetVal)) {
    RetVal = I->getOperand(0);
  }
  if (auto *I = dyn_cast<CallInst>(RetVal)) {
    return I->isMustTailCall();
  }
  return false;
}

void visitReturnInst(ReturnInst &I) {
  IRBuilder<> IRB(&I);
  Value *RetVal = I.getReturnValue();
  if (!RetVal) return;
  // Don't emit the epilogue for musttail call returns.
  if (isAMustTailRetVal(RetVal)) return;
  Value *ShadowPtr = getShadowPtrForRetval(RetVal, IRB);
  if (CheckReturnValue) {
    insertShadowCheck(RetVal, &I);
    Value *Shadow = getCleanShadow(RetVal);
    IRB.CreateAlignedStore(Shadow, ShadowPtr, kShadowTLSAlignment.value());
  } else {
    Value *Shadow = getShadow(RetVal);
    IRB.CreateAlignedStore(Shadow, ShadowPtr, kShadowTLSAlignment.value());
    if (MS.TrackOrigins)
      IRB.CreateStore(getOrigin(RetVal), getOriginPtrForRetval(IRB));
  }
}

void visitPHINode(PHINode &I) {
  IRBuilder<> IRB(&I);
  if (!PropagateShadow) {
    setShadow(&I, getCleanShadow(&I));
    setOrigin(&I, getCleanOrigin());
    return;
  }

  ShadowPHINodes.push_back(&I);
  setShadow(&I, IRB.CreatePHI(getShadowTy(&I), I.getNumIncomingValues(),
                              "_msphi_s"));
  if (MS.TrackOrigins)
    setOrigin(&I, IRB.CreatePHI(MS.OriginTy, I.getNumIncomingValues(),
                                "_msphi_o"));
}

Value *getLocalVarDescription(AllocaInst &I) {
  SmallString<2048> StackDescriptionStorage;
  raw_svector_ostream StackDescription(StackDescriptionStorage);
  // We create a string with a description of the stack allocation and
  // pass it into __msan_set_alloca_origin.
  // It will be printed by the run-time if stack-originated UMR is found.
  // The first 4 bytes of the string are set to '----' and will be replaced
  // by __msan_va_arg_overflow_size_tls at the first call.
  StackDescription << "----" << I.getName() << "@" << F.getName();
  return createPrivateNonConstGlobalForString(*F.getParent(),
                                              StackDescription.str());
}

void poisonAllocaUserspace(AllocaInst &I, IRBuilder<> &IRB, Value *Len) {
  if (PoisonStack && ClPoisonStackWithCall) {
    IRB.CreateCall(MS.MsanPoisonStackFn,
                   {IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()), Len});
  } else {
    Value *ShadowBase, *OriginBase;
    std::tie(ShadowBase, OriginBase) = getShadowOriginPtr(
        &I, IRB, IRB.getInt8Ty(), Align::None(), /*isStore*/ true);

    Value *PoisonValue = IRB.getInt8(PoisonStack ? ClPoisonStackPattern : 0);
    IRB.CreateMemSet(ShadowBase, PoisonValue, Len,
                     MaybeAlign(I.getAlignment()));
  }

  if (PoisonStack && MS.TrackOrigins) {
    Value *Descr = getLocalVarDescription(I);
    IRB.CreateCall(MS.MsanSetAllocaOrigin4Fn,
                   {IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()), Len,
                    IRB.CreatePointerCast(Descr, IRB.getInt8PtrTy()),
                    IRB.CreatePointerCast(&F, MS.IntptrTy)});
  }
}

void poisonAllocaKmsan(AllocaInst &I, IRBuilder<> &IRB, Value *Len) {
  Value *Descr = getLocalVarDescription(I);
  if (PoisonStack) {
    IRB.CreateCall(MS.MsanPoisonAllocaFn,
                   {IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()), Len,
                    IRB.CreatePointerCast(Descr, IRB.getInt8PtrTy())});
  } else {
    IRB.CreateCall(MS.MsanUnpoisonAllocaFn,
                   {IRB.CreatePointerCast(&I, IRB.getInt8PtrTy()), Len});
  }
}

void instrumentAlloca(AllocaInst &I, Instruction *InsPoint = nullptr) {
  if (!InsPoint)
    InsPoint = &I;
  IRBuilder<> IRB(InsPoint->getNextNode());
  const DataLayout &DL = F.getParent()->getDataLayout();
  uint64_t TypeSize = DL.getTypeAllocSize(I.getAllocatedType());
  Value *Len = ConstantInt::get(MS.IntptrTy, TypeSize);
  if (I.isArrayAllocation())
    Len = IRB.CreateMul(Len, I.getArraySize());

  if (MS.CompileKernel)
    poisonAllocaKmsan(I, IRB, Len);
  else
    poisonAllocaUserspace(I, IRB, Len);
}

void visitAllocaInst(AllocaInst &I) {
  setShadow(&I, getCleanShadow(&I));
  setOrigin(&I, getCleanOrigin());
  // We'll get to this alloca later unless it's poisoned at the corresponding
  // llvm.lifetime.start.
  AllocaSet.insert(&I);
}

void visitSelectInst(SelectInst& I) {
  IRBuilder<> IRB(&I);
  // a = select b, c, d
  Value *B = I.getCondition();
  Value *C = I.getTrueValue();
  Value *D = I.getFalseValue();
  Value *Sb = getShadow(B);
  Value *Sc = getShadow(C);
  Value *Sd = getShadow(D);

  // Result shadow if condition shadow is 0.
  Value *Sa0 = IRB.CreateSelect(B, Sc, Sd);
  Value *Sa1;
  if (I.getType()->isAggregateType()) {
    // To avoid "sign extending" i1 to an arbitrary aggregate type, we just do
    // an extra "select". This results in much more compact IR.
    // Sa = select Sb, poisoned, (select b, Sc, Sd)
    Sa1 = getPoisonedShadow(getShadowTy(I.getType()));
  } else {
    // Sa = select Sb, [ (c^d) | Sc | Sd ], [ b ? Sc : Sd ]
    // If Sb (condition is poisoned), look for bits in c and d that are equal
    // and both unpoisoned.
    // If !Sb (condition is unpoisoned), simply pick one of Sc and Sd.

    // Cast arguments to shadow-compatible type.
    C = CreateAppToShadowCast(IRB, C);
    D = CreateAppToShadowCast(IRB, D);

    // Result shadow if condition shadow is 1.
    Sa1 = IRB.CreateOr({IRB.CreateXor(C, D), Sc, Sd});
  }
  Value *Sa = IRB.CreateSelect(Sb, Sa1, Sa0, "_msprop_select");
  setShadow(&I, Sa);
  if (MS.TrackOrigins) {
    // Origins are always i32, so any vector conditions must be flattened.
    // FIXME: consider tracking vector origins for app vectors?
    if (B->getType()->isVectorTy()) {
      Type *FlatTy = getShadowTyNoVec(B->getType());
      B = IRB.CreateICmpNE(IRB.CreateBitCast(B, FlatTy),
                              ConstantInt::getNullValue(FlatTy));
      Sb = IRB.CreateICmpNE(IRB.CreateBitCast(Sb, FlatTy),
                                    ConstantInt::getNullValue(FlatTy));
    }
    // a = select b, c, d
    // Oa = Sb ? Ob : (b ? Oc : Od)
    setOrigin(
        &I, IRB.CreateSelect(Sb, getOrigin(I.getCondition()),
                             IRB.CreateSelect(B, getOrigin(I.getTrueValue()),
                                              getOrigin(I.getFalseValue()))));
  }
}

void visitLandingPadInst(LandingPadInst &I) {
  // Do nothing.
  // See https://github.com/google/sanitizers/issues/504
  setShadow(&I, getCleanShadow(&I));
  setOrigin(&I, getCleanOrigin());
}

void visitCatchSwitchInst(CatchSwitchInst &I) {
  setShadow(&I, getCleanShadow(&I));
  setOrigin(&I, getCleanOrigin());
}

void visitFuncletPadInst(FuncletPadInst &I) {
  setShadow(&I, getCleanShadow(&I));
  setOrigin(&I, getCleanOrigin());
}

void visitGetElementPtrInst(GetElementPtrInst &I) {
  handleShadowOr(I);
}

void visitExtractValueInst(ExtractValueInst &I) {
  IRBuilder<> IRB(&I);
  Value *Agg = I.getAggregateOperand();
  LLVM_DEBUG(dbgs() << "ExtractValue:  " << I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "ExtractValue:  " << I <<
 "\n"; } } while (false);
  Value *AggShadow = getShadow(Agg);
  LLVM_DEBUG(dbgs() << "   AggShadow:  " << *AggShadow << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "   AggShadow:  " << *AggShadow
 << "\n"; } } while (false);
  Value *ResShadow = IRB.CreateExtractValue(AggShadow, I.getIndices());
  LLVM_DEBUG(dbgs() << "   ResShadow:  " << *ResShadow << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "   ResShadow:  " << *ResShadow
 << "\n"; } } while (false);
  setShadow(&I, ResShadow);
  setOriginForNaryOp(I);
}

void visitInsertValueInst(InsertValueInst &I) {
  IRBuilder<> IRB(&I);
  LLVM_DEBUG(dbgs() << "InsertValue:  " << I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "InsertValue:  " << I <<
 "\n"; } } while (false);
  Value *AggShadow = getShadow(I.getAggregateOperand());
  Value *InsShadow = getShadow(I.getInsertedValueOperand());
  LLVM_DEBUG(dbgs() << "   AggShadow:  " << *AggShadow << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "   AggShadow:  " << *AggShadow
 << "\n"; } } while (false);
  LLVM_DEBUG(dbgs() << "   InsShadow:  " << *InsShadow << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "   InsShadow:  " << *InsShadow
 << "\n"; } } while (false);
  Value *Res = IRB.CreateInsertValue(AggShadow, InsShadow, I.getIndices());
  LLVM_DEBUG(dbgs() << "   Res:        " << *Res << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "   Res:        " << *Res <<
 "\n"; } } while (false);
  setShadow(&I, Res);
  setOriginForNaryOp(I);
}

void dumpInst(Instruction &I) {
  if (CallInst *CI = dyn_cast<CallInst>(&I)) {
    errs() << "ZZZ call " << CI->getCalledFunction()->getName() << "\n";
  } else {
    errs() << "ZZZ " << I.getOpcodeName() << "\n";
  }
  errs() << "QQQ " << I << "\n";
}

void visitResumeInst(ResumeInst &I) {
  LLVM_DEBUG(dbgs() << "Resume: " << I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "Resume: " << I << "\n"
; } } while (false);
  // Nothing to do here.
}

void visitCleanupReturnInst(CleanupReturnInst &CRI) {
  LLVM_DEBUG(dbgs() << "CleanupReturn: " << CRI << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "CleanupReturn: " << CRI <<
 "\n"; } } while (false);
  // Nothing to do here.
}

void visitCatchReturnInst(CatchReturnInst &CRI) {
  LLVM_DEBUG(dbgs() << "CatchReturn: " << CRI << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "CatchReturn: " << CRI <<
 "\n"; } } while (false);
  // Nothing to do here.
}

void instrumentAsmArgument(Value *Operand, Instruction &I, IRBuilder<> &IRB,
                           const DataLayout &DL, bool isOutput) {
  // For each assembly argument, we check its value for being initialized.
  // If the argument is a pointer, we assume it points to a single element
  // of the corresponding type (or to a 8-byte word, if the type is unsized).
  // Each such pointer is instrumented with a call to the runtime library.
  Type *OpType = Operand->getType();
  // Check the operand value itself.
  insertShadowCheck(Operand, &I);
  if (!OpType->isPointerTy() || !isOutput) {
    assert(!isOutput)((!isOutput) ? static_cast<void> (0) : __assert_fail ("!isOutput"
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3644, __PRETTY_FUNCTION__));
    return;
  }
  Type *ElType = OpType->getPointerElementType();
  if (!ElType->isSized())
    return;
  int Size = DL.getTypeStoreSize(ElType);
  Value *Ptr = IRB.CreatePointerCast(Operand, IRB.getInt8PtrTy());
  Value *SizeVal = ConstantInt::get(MS.IntptrTy, Size);
  IRB.CreateCall(MS.MsanInstrumentAsmStoreFn, {Ptr, SizeVal});
}

/// Get the number of output arguments returned by pointers.
int getNumOutputArgs(InlineAsm *IA, CallBase *CB) {
  int NumRetOutputs = 0;
  int NumOutputs = 0;
  Type *RetTy = cast<Value>(CB)->getType();
  if (!RetTy->isVoidTy()) {
    // Register outputs are returned via the CallInst return value.
    auto *ST = dyn_cast<StructType>(RetTy);
    if (ST)
      NumRetOutputs = ST->getNumElements();
    else
      NumRetOutputs = 1;
  }
  InlineAsm::ConstraintInfoVector Constraints = IA->ParseConstraints();
  for (size_t i = 0, n = Constraints.size(); i < n; i++) {
    InlineAsm::ConstraintInfo Info = Constraints[i];
    switch (Info.Type) {
    case InlineAsm::isOutput:
      NumOutputs++;
      break;
    default:
      break;
    }
  }
  return NumOutputs - NumRetOutputs;
}

void visitAsmInstruction(Instruction &I) {
  // Conservative inline assembly handling: check for poisoned shadow of
  // asm() arguments, then unpoison the result and all the memory locations
  // pointed to by those arguments.
  // An inline asm() statement in C++ contains lists of input and output
  // arguments used by the assembly code. These are mapped to operands of the
  // CallInst as follows:
  //  - nR register outputs ("=r) are returned by value in a single structure
  //  (SSA value of the CallInst);
  //  - nO other outputs ("=m" and others) are returned by pointer as first
  // nO operands of the CallInst;
  //  - nI inputs ("r", "m" and others) are passed to CallInst as the
  // remaining nI operands.
  // The total number of asm() arguments in the source is nR+nO+nI, and the
  // corresponding CallInst has nO+nI+1 operands (the last operand is the
  // function to be called).
  const DataLayout &DL = F.getParent()->getDataLayout();
  CallBase *CB = cast<CallBase>(&I);
  IRBuilder<> IRB(&I);
  InlineAsm *IA = cast<InlineAsm>(CB->getCalledValue());
  int OutputArgs = getNumOutputArgs(IA, CB);
  // The last operand of a CallInst is the function itself.
  int NumOperands = CB->getNumOperands() - 1;

  // Check input arguments. Doing so before unpoisoning output arguments, so
  // that we won't overwrite uninit values before checking them.
  for (int i = OutputArgs; i < NumOperands; i++) {
    Value *Operand = CB->getOperand(i);
    instrumentAsmArgument(Operand, I, IRB, DL, /*isOutput*/ false);
  }
  // Unpoison output arguments. This must happen before the actual InlineAsm
  // call, so that the shadow for memory published in the asm() statement
  // remains valid.
  for (int i = 0; i < OutputArgs; i++) {
    Value *Operand = CB->getOperand(i);
    instrumentAsmArgument(Operand, I, IRB, DL, /*isOutput*/ true);
  }

  setShadow(&I, getCleanShadow(&I));
  setOrigin(&I, getCleanOrigin());
}

void visitInstruction(Instruction &I) {
  // Everything else: stop propagating and check for poisoned shadow.
  if (ClDumpStrictInstructions)
    dumpInst(I);
  LLVM_DEBUG(dbgs() << "DEFAULT: " << I << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("msan")) { dbgs() << "DEFAULT: " << I << "\n"
; } } while (false);
  for (size_t i = 0, n = I.getNumOperands(); i < n; i++) {
    Value *Operand = I.getOperand(i);
    if (Operand->getType()->isSized())
      insertShadowCheck(Operand, &I);
  }
  setShadow(&I, getCleanShadow(&I));
  setOrigin(&I, getCleanOrigin());
}
3738};

3740/// AMD64-specific implementation of VarArgHelper.
3741struct VarArgAMD64Helper : public VarArgHelper {
// An unfortunate workaround for asymmetric lowering of va_arg stuff.
// See a comment in visitCallSite for more details.
static const unsigned AMD64GpEndOffset = 48;  // AMD64 ABI Draft 0.99.6 p3.5.7
static const unsigned AMD64FpEndOffsetSSE = 176;
// If SSE is disabled, fp_offset in va_list is zero.
static const unsigned AMD64FpEndOffsetNoSSE = AMD64GpEndOffset;

unsigned AMD64FpEndOffset;
Function &F;
MemorySanitizer &MS;
MemorySanitizerVisitor &MSV;
Value *VAArgTLSCopy = nullptr;
Value *VAArgTLSOriginCopy = nullptr;
Value *VAArgOverflowSize = nullptr;

SmallVector<CallInst*, 16> VAStartInstrumentationList;

enum ArgKind { AK_GeneralPurpose, AK_FloatingPoint, AK_Memory };

VarArgAMD64Helper(Function &F, MemorySanitizer &MS,
                  MemorySanitizerVisitor &MSV)
    : F(F), MS(MS), MSV(MSV) {
  AMD64FpEndOffset = AMD64FpEndOffsetSSE;
  for (const auto &Attr : F.getAttributes().getFnAttributes()) {
    if (Attr.isStringAttribute() &&
        (Attr.getKindAsString() == "target-features")) {
      if (Attr.getValueAsString().contains("-sse"))
        AMD64FpEndOffset = AMD64FpEndOffsetNoSSE;
      break;
    }
  }
}

ArgKind classifyArgument(Value* arg) {
  // A very rough approximation of X86_64 argument classification rules.
  Type *T = arg->getType();
  if (T->isFPOrFPVectorTy() || T->isX86_MMXTy())
    return AK_FloatingPoint;
  if (T->isIntegerTy() && T->getPrimitiveSizeInBits() <= 64)
    return AK_GeneralPurpose;
  if (T->isPointerTy())
    return AK_GeneralPurpose;
  return AK_Memory;
}

// For VarArg functions, store the argument shadow in an ABI-specific format
// that corresponds to va_list layout.
// We do this because Clang lowers va_arg in the frontend, and this pass
// only sees the low level code that deals with va_list internals.
// A much easier alternative (provided that Clang emits va_arg instructions)
// would have been to associate each live instance of va_list with a copy of
// MSanParamTLS, and extract shadow on va_arg() call in the argument list
// order.
void visitCallSite(CallSite &CS, IRBuilder<> &IRB) override {
  unsigned GpOffset = 0;
  unsigned FpOffset = AMD64GpEndOffset;
  unsigned OverflowOffset = AMD64FpEndOffset;
  const DataLayout &DL = F.getParent()->getDataLayout();
  for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End = CS.arg_end();
       ArgIt != End; ++ArgIt) {
    Value *A = *ArgIt;
    unsigned ArgNo = CS.getArgumentNo(ArgIt);
    bool IsFixed = ArgNo < CS.getFunctionType()->getNumParams();
    bool IsByVal = CS.paramHasAttr(ArgNo, Attribute::ByVal);
    if (IsByVal) {
      // ByVal arguments always go to the overflow area.
      // Fixed arguments passed through the overflow area will be stepped
      // over by va_start, so don't count them towards the offset.
      if (IsFixed)
        continue;
      assert(A->getType()->isPointerTy())((A->getType()->isPointerTy()) ? static_cast<void>
 (0) : __assert_fail ("A->getType()->isPointerTy()", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3812, __PRETTY_FUNCTION__));
      Type *RealTy = A->getType()->getPointerElementType();
      uint64_t ArgSize = DL.getTypeAllocSize(RealTy);
      Value *ShadowBase = getShadowPtrForVAArgument(
          RealTy, IRB, OverflowOffset, alignTo(ArgSize, 8));
      Value *OriginBase = nullptr;
      if (MS.TrackOrigins)
        OriginBase = getOriginPtrForVAArgument(RealTy, IRB, OverflowOffset);
      OverflowOffset += alignTo(ArgSize, 8);
      if (!ShadowBase)
        continue;
      Value *ShadowPtr, *OriginPtr;
      std::tie(ShadowPtr, OriginPtr) =
          MSV.getShadowOriginPtr(A, IRB, IRB.getInt8Ty(), kShadowTLSAlignment,
                                 /*isStore*/ false);

      IRB.CreateMemCpy(ShadowBase, kShadowTLSAlignment, ShadowPtr,
                       kShadowTLSAlignment, ArgSize);
      if (MS.TrackOrigins)
        IRB.CreateMemCpy(OriginBase, kShadowTLSAlignment, OriginPtr,
                         kShadowTLSAlignment, ArgSize);
    } else {
      ArgKind AK = classifyArgument(A);
      if (AK == AK_GeneralPurpose && GpOffset >= AMD64GpEndOffset)
        AK = AK_Memory;
      if (AK == AK_FloatingPoint && FpOffset >= AMD64FpEndOffset)
        AK = AK_Memory;
      Value *ShadowBase, *OriginBase = nullptr;
      switch (AK) {
        case AK_GeneralPurpose:
          ShadowBase =
              getShadowPtrForVAArgument(A->getType(), IRB, GpOffset, 8);
          if (MS.TrackOrigins)
            OriginBase =
                getOriginPtrForVAArgument(A->getType(), IRB, GpOffset);
          GpOffset += 8;
          break;
        case AK_FloatingPoint:
          ShadowBase =
              getShadowPtrForVAArgument(A->getType(), IRB, FpOffset, 16);
          if (MS.TrackOrigins)
            OriginBase =
                getOriginPtrForVAArgument(A->getType(), IRB, FpOffset);
          FpOffset += 16;
          break;
        case AK_Memory:
          if (IsFixed)
            continue;
          uint64_t ArgSize = DL.getTypeAllocSize(A->getType());
          ShadowBase =
              getShadowPtrForVAArgument(A->getType(), IRB, OverflowOffset, 8);
          if (MS.TrackOrigins)
            OriginBase =
                getOriginPtrForVAArgument(A->getType(), IRB, OverflowOffset);
          OverflowOffset += alignTo(ArgSize, 8);
      }
      // Take fixed arguments into account for GpOffset and FpOffset,
      // but don't actually store shadows for them.
      // TODO(glider): don't call get*PtrForVAArgument() for them.
      if (IsFixed)
        continue;
      if (!ShadowBase)
        continue;
      Value *Shadow = MSV.getShadow(A);
      IRB.CreateAlignedStore(Shadow, ShadowBase, kShadowTLSAlignment.value());
      if (MS.TrackOrigins) {
        Value *Origin = MSV.getOrigin(A);
        unsigned StoreSize = DL.getTypeStoreSize(Shadow->getType());
        MSV.paintOrigin(IRB, Origin, OriginBase, StoreSize,
                        std::max(kShadowTLSAlignment, kMinOriginAlignment));
      }
    }
  }
  Constant *OverflowSize =
    ConstantInt::get(IRB.getInt64Ty(), OverflowOffset - AMD64FpEndOffset);
  IRB.CreateStore(OverflowSize, MS.VAArgOverflowSizeTLS);
}

/// Compute the shadow address for a given va_arg.
Value *getShadowPtrForVAArgument(Type *Ty, IRBuilder<> &IRB,
                                 unsigned ArgOffset, unsigned ArgSize) {
  // Make sure we don't overflow __msan_va_arg_tls.
  if (ArgOffset + ArgSize > kParamTLSSize)
    return nullptr;
  Value *Base = IRB.CreatePointerCast(MS.VAArgTLS, MS.IntptrTy);
  Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
  return IRB.CreateIntToPtr(Base, PointerType::get(MSV.getShadowTy(Ty), 0),
                            "_msarg_va_s");
}

/// Compute the origin address for a given va_arg.
Value *getOriginPtrForVAArgument(Type *Ty, IRBuilder<> &IRB, int ArgOffset) {
  Value *Base = IRB.CreatePointerCast(MS.VAArgOriginTLS, MS.IntptrTy);
  // getOriginPtrForVAArgument() is always called after
  // getShadowPtrForVAArgument(), so __msan_va_arg_origin_tls can never
  // overflow.
  Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
  return IRB.CreateIntToPtr(Base, PointerType::get(MS.OriginTy, 0),
                            "_msarg_va_o");
}

void unpoisonVAListTagForInst(IntrinsicInst &I) {
  IRBuilder<> IRB(&I);
  Value *VAListTag = I.getArgOperand(0);
  Value *ShadowPtr, *OriginPtr;
  const Align Alignment = Align(8);
  std::tie(ShadowPtr, OriginPtr) =
      MSV.getShadowOriginPtr(VAListTag, IRB, IRB.getInt8Ty(), Alignment,
                             /*isStore*/ true);

  // Unpoison the whole __va_list_tag.
  // FIXME: magic ABI constants.
  IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
                   /* size */ 24, Alignment, false);
  // We shouldn't need to zero out the origins, as they're only checked for
  // nonzero shadow.
}

void visitVAStartInst(VAStartInst &I) override {
  if (F.getCallingConv() == CallingConv::Win64)
    return;
  VAStartInstrumentationList.push_back(&I);
  unpoisonVAListTagForInst(I);
}

void visitVACopyInst(VACopyInst &I) override {
  if (F.getCallingConv() == CallingConv::Win64) return;
  unpoisonVAListTagForInst(I);
}

void finalizeInstrumentation() override {
  assert(!VAArgOverflowSize && !VAArgTLSCopy &&((!VAArgOverflowSize && !VAArgTLSCopy && "finalizeInstrumentation called twice"
) ? static_cast<void> (0) : __assert_fail ("!VAArgOverflowSize && !VAArgTLSCopy && \"finalizeInstrumentation called twice\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3944, __PRETTY_FUNCTION__))
         "finalizeInstrumentation called twice")((!VAArgOverflowSize && !VAArgTLSCopy && "finalizeInstrumentation called twice"
) ? static_cast<void> (0) : __assert_fail ("!VAArgOverflowSize && !VAArgTLSCopy && \"finalizeInstrumentation called twice\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 3944, __PRETTY_FUNCTION__));
  if (!VAStartInstrumentationList.empty()) {
    // If there is a va_start in this function, make a backup copy of
    // va_arg_tls somewhere in the function entry block.
    IRBuilder<> IRB(MSV.ActualFnStart->getFirstNonPHI());
    VAArgOverflowSize =
        IRB.CreateLoad(IRB.getInt64Ty(), MS.VAArgOverflowSizeTLS);
    Value *CopySize =
      IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, AMD64FpEndOffset),
                    VAArgOverflowSize);
    VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
    IRB.CreateMemCpy(VAArgTLSCopy, Align(8), MS.VAArgTLS, Align(8), CopySize);
    if (MS.TrackOrigins) {
      VAArgTLSOriginCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
      IRB.CreateMemCpy(VAArgTLSOriginCopy, Align(8), MS.VAArgOriginTLS,
                       Align(8), CopySize);
    }
  }

  // Instrument va_start.
  // Copy va_list shadow from the backup copy of the TLS contents.
  for (size_t i = 0, n = VAStartInstrumentationList.size(); i < n; i++) {
    CallInst *OrigInst = VAStartInstrumentationList[i];
    IRBuilder<> IRB(OrigInst->getNextNode());
    Value *VAListTag = OrigInst->getArgOperand(0);

    Type *RegSaveAreaPtrTy = Type::getInt64PtrTy(*MS.C);
    Value *RegSaveAreaPtrPtr = IRB.CreateIntToPtr(
        IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
                      ConstantInt::get(MS.IntptrTy, 16)),
        PointerType::get(RegSaveAreaPtrTy, 0));
    Value *RegSaveAreaPtr =
        IRB.CreateLoad(RegSaveAreaPtrTy, RegSaveAreaPtrPtr);
    Value *RegSaveAreaShadowPtr, *RegSaveAreaOriginPtr;
    const Align Alignment = Align(16);
    std::tie(RegSaveAreaShadowPtr, RegSaveAreaOriginPtr) =
        MSV.getShadowOriginPtr(RegSaveAreaPtr, IRB, IRB.getInt8Ty(),
                               Alignment, /*isStore*/ true);
    IRB.CreateMemCpy(RegSaveAreaShadowPtr, Alignment, VAArgTLSCopy, Alignment,
                     AMD64FpEndOffset);
    if (MS.TrackOrigins)
      IRB.CreateMemCpy(RegSaveAreaOriginPtr, Alignment, VAArgTLSOriginCopy,
                       Alignment, AMD64FpEndOffset);
    Type *OverflowArgAreaPtrTy = Type::getInt64PtrTy(*MS.C);
    Value *OverflowArgAreaPtrPtr = IRB.CreateIntToPtr(
        IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
                      ConstantInt::get(MS.IntptrTy, 8)),
        PointerType::get(OverflowArgAreaPtrTy, 0));
    Value *OverflowArgAreaPtr =
        IRB.CreateLoad(OverflowArgAreaPtrTy, OverflowArgAreaPtrPtr);
    Value *OverflowArgAreaShadowPtr, *OverflowArgAreaOriginPtr;
    std::tie(OverflowArgAreaShadowPtr, OverflowArgAreaOriginPtr) =
        MSV.getShadowOriginPtr(OverflowArgAreaPtr, IRB, IRB.getInt8Ty(),
                               Alignment, /*isStore*/ true);
    Value *SrcPtr = IRB.CreateConstGEP1_32(IRB.getInt8Ty(), VAArgTLSCopy,
                                           AMD64FpEndOffset);
    IRB.CreateMemCpy(OverflowArgAreaShadowPtr, Alignment, SrcPtr, Alignment,
                     VAArgOverflowSize);
    if (MS.TrackOrigins) {
      SrcPtr = IRB.CreateConstGEP1_32(IRB.getInt8Ty(), VAArgTLSOriginCopy,
                                      AMD64FpEndOffset);
      IRB.CreateMemCpy(OverflowArgAreaOriginPtr, Alignment, SrcPtr, Alignment,
                       VAArgOverflowSize);
    }
  }
}
4010};

4012/// MIPS64-specific implementation of VarArgHelper.
4013struct VarArgMIPS64Helper : public VarArgHelper {
Function &F;
MemorySanitizer &MS;
MemorySanitizerVisitor &MSV;
Value *VAArgTLSCopy = nullptr;
Value *VAArgSize = nullptr;

SmallVector<CallInst*, 16> VAStartInstrumentationList;

VarArgMIPS64Helper(Function &F, MemorySanitizer &MS,
                  MemorySanitizerVisitor &MSV) : F(F), MS(MS), MSV(MSV) {}

void visitCallSite(CallSite &CS, IRBuilder<> &IRB) override {
  unsigned VAArgOffset = 0;
  const DataLayout &DL = F.getParent()->getDataLayout();
  for (CallSite::arg_iterator ArgIt = CS.arg_begin() +
       CS.getFunctionType()->getNumParams(), End = CS.arg_end();
       ArgIt != End; ++ArgIt) {
    Triple TargetTriple(F.getParent()->getTargetTriple());
    Value *A = *ArgIt;
    Value *Base;
    uint64_t ArgSize = DL.getTypeAllocSize(A->getType());
    if (TargetTriple.getArch() == Triple::mips64) {
      // Adjusting the shadow for argument with size < 8 to match the placement
      // of bits in big endian system
      if (ArgSize < 8)
        VAArgOffset += (8 - ArgSize);
    }
    Base = getShadowPtrForVAArgument(A->getType(), IRB, VAArgOffset, ArgSize);
    VAArgOffset += ArgSize;
    VAArgOffset = alignTo(VAArgOffset, 8);
    if (!Base)
      continue;
    IRB.CreateAlignedStore(MSV.getShadow(A), Base,
                           kShadowTLSAlignment.value());
  }

  Constant *TotalVAArgSize = ConstantInt::get(IRB.getInt64Ty(), VAArgOffset);
  // Here using VAArgOverflowSizeTLS as VAArgSizeTLS to avoid creation of
  // a new class member i.e. it is the total size of all VarArgs.
  IRB.CreateStore(TotalVAArgSize, MS.VAArgOverflowSizeTLS);
}

/// Compute the shadow address for a given va_arg.
Value *getShadowPtrForVAArgument(Type *Ty, IRBuilder<> &IRB,
                                 unsigned ArgOffset, unsigned ArgSize) {
  // Make sure we don't overflow __msan_va_arg_tls.
  if (ArgOffset + ArgSize > kParamTLSSize)
    return nullptr;
  Value *Base = IRB.CreatePointerCast(MS.VAArgTLS, MS.IntptrTy);
  Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
  return IRB.CreateIntToPtr(Base, PointerType::get(MSV.getShadowTy(Ty), 0),
                            "_msarg");
}

void visitVAStartInst(VAStartInst &I) override {
  IRBuilder<> IRB(&I);
  VAStartInstrumentationList.push_back(&I);
  Value *VAListTag = I.getArgOperand(0);
  Value *ShadowPtr, *OriginPtr;
  const Align Alignment = Align(8);
  std::tie(ShadowPtr, OriginPtr) = MSV.getShadowOriginPtr(
      VAListTag, IRB, IRB.getInt8Ty(), Alignment, /*isStore*/ true);
  IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
                   /* size */ 8, Alignment, false);
}

void visitVACopyInst(VACopyInst &I) override {
  IRBuilder<> IRB(&I);
  VAStartInstrumentationList.push_back(&I);
  Value *VAListTag = I.getArgOperand(0);
  Value *ShadowPtr, *OriginPtr;
  const Align Alignment = Align(8);
  std::tie(ShadowPtr, OriginPtr) = MSV.getShadowOriginPtr(
      VAListTag, IRB, IRB.getInt8Ty(), Alignment, /*isStore*/ true);
  IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
                   /* size */ 8, Alignment, false);
}

void finalizeInstrumentation() override {
  assert(!VAArgSize && !VAArgTLSCopy &&((!VAArgSize && !VAArgTLSCopy && "finalizeInstrumentation called twice"
) ? static_cast<void> (0) : __assert_fail ("!VAArgSize && !VAArgTLSCopy && \"finalizeInstrumentation called twice\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 4094, __PRETTY_FUNCTION__))
         "finalizeInstrumentation called twice")((!VAArgSize && !VAArgTLSCopy && "finalizeInstrumentation called twice"
) ? static_cast<void> (0) : __assert_fail ("!VAArgSize && !VAArgTLSCopy && \"finalizeInstrumentation called twice\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 4094, __PRETTY_FUNCTION__));
  IRBuilder<> IRB(MSV.ActualFnStart->getFirstNonPHI());
  VAArgSize = IRB.CreateLoad(IRB.getInt64Ty(), MS.VAArgOverflowSizeTLS);
  Value *CopySize = IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, 0),
                                  VAArgSize);

  if (!VAStartInstrumentationList.empty()) {
    // If there is a va_start in this function, make a backup copy of
    // va_arg_tls somewhere in the function entry block.
    VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
    IRB.CreateMemCpy(VAArgTLSCopy, Align(8), MS.VAArgTLS, Align(8), CopySize);
  }

  // Instrument va_start.
  // Copy va_list shadow from the backup copy of the TLS contents.
  for (size_t i = 0, n = VAStartInstrumentationList.size(); i < n; i++) {
    CallInst *OrigInst = VAStartInstrumentationList[i];
    IRBuilder<> IRB(OrigInst->getNextNode());
    Value *VAListTag = OrigInst->getArgOperand(0);
    Type *RegSaveAreaPtrTy = Type::getInt64PtrTy(*MS.C);
    Value *RegSaveAreaPtrPtr =
        IRB.CreateIntToPtr(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
                           PointerType::get(RegSaveAreaPtrTy, 0));
    Value *RegSaveAreaPtr =
        IRB.CreateLoad(RegSaveAreaPtrTy, RegSaveAreaPtrPtr);
    Value *RegSaveAreaShadowPtr, *RegSaveAreaOriginPtr;
    const Align Alignment = Align(8);
    std::tie(RegSaveAreaShadowPtr, RegSaveAreaOriginPtr) =
        MSV.getShadowOriginPtr(RegSaveAreaPtr, IRB, IRB.getInt8Ty(),
                               Alignment, /*isStore*/ true);
    IRB.CreateMemCpy(RegSaveAreaShadowPtr, Alignment, VAArgTLSCopy, Alignment,
                     CopySize);
  }
}
4128};

4130/// AArch64-specific implementation of VarArgHelper.
4131struct VarArgAArch64Helper : public VarArgHelper {
static const unsigned kAArch64GrArgSize = 64;
static const unsigned kAArch64VrArgSize = 128;

static const unsigned AArch64GrBegOffset = 0;
static const unsigned AArch64GrEndOffset = kAArch64GrArgSize;
// Make VR space aligned to 16 bytes.
static const unsigned AArch64VrBegOffset = AArch64GrEndOffset;
static const unsigned AArch64VrEndOffset = AArch64VrBegOffset
                                           + kAArch64VrArgSize;
static const unsigned AArch64VAEndOffset = AArch64VrEndOffset;

Function &F;
MemorySanitizer &MS;
MemorySanitizerVisitor &MSV;
Value *VAArgTLSCopy = nullptr;
Value *VAArgOverflowSize = nullptr;

SmallVector<CallInst*, 16> VAStartInstrumentationList;

enum ArgKind { AK_GeneralPurpose, AK_FloatingPoint, AK_Memory };

VarArgAArch64Helper(Function &F, MemorySanitizer &MS,
                  MemorySanitizerVisitor &MSV) : F(F), MS(MS), MSV(MSV) {}

ArgKind classifyArgument(Value* arg) {
  Type *T = arg->getType();
  if (T->isFPOrFPVectorTy())
    return AK_FloatingPoint;
  if ((T->isIntegerTy() && T->getPrimitiveSizeInBits() <= 64)
      || (T->isPointerTy()))
    return AK_GeneralPurpose;
  return AK_Memory;
}

// The instrumentation stores the argument shadow in a non ABI-specific
// format because it does not know which argument is named (since Clang,
// like x86_64 case, lowers the va_args in the frontend and this pass only
// sees the low level code that deals with va_list internals).
// The first seven GR registers are saved in the first 56 bytes of the
// va_arg tls arra, followers by the first 8 FP/SIMD registers, and then
// the remaining arguments.
// Using constant offset within the va_arg TLS array allows fast copy
// in the finalize instrumentation.
void visitCallSite(CallSite &CS, IRBuilder<> &IRB) override {
  unsigned GrOffset = AArch64GrBegOffset;
  unsigned VrOffset = AArch64VrBegOffset;
  unsigned OverflowOffset = AArch64VAEndOffset;

  const DataLayout &DL = F.getParent()->getDataLayout();
  for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End = CS.arg_end();
       ArgIt != End; ++ArgIt) {
    Value *A = *ArgIt;
    unsigned ArgNo = CS.getArgumentNo(ArgIt);
    bool IsFixed = ArgNo < CS.getFunctionType()->getNumParams();
    ArgKind AK = classifyArgument(A);
    if (AK == AK_GeneralPurpose && GrOffset >= AArch64GrEndOffset)
      AK = AK_Memory;
    if (AK == AK_FloatingPoint && VrOffset >= AArch64VrEndOffset)
      AK = AK_Memory;
    Value *Base;
    switch (AK) {
      case AK_GeneralPurpose:
        Base = getShadowPtrForVAArgument(A->getType(), IRB, GrOffset, 8);
        GrOffset += 8;
        break;
      case AK_FloatingPoint:
        Base = getShadowPtrForVAArgument(A->getType(), IRB, VrOffset, 8);
        VrOffset += 16;
        break;
      case AK_Memory:
        // Don't count fixed arguments in the overflow area - va_start will
        // skip right over them.
        if (IsFixed)
          continue;
        uint64_t ArgSize = DL.getTypeAllocSize(A->getType());
        Base = getShadowPtrForVAArgument(A->getType(), IRB, OverflowOffset,
                                         alignTo(ArgSize, 8));
        OverflowOffset += alignTo(ArgSize, 8);
        break;
    }
    // Count Gp/Vr fixed arguments to their respective offsets, but don't
    // bother to actually store a shadow.
    if (IsFixed)
      continue;
    if (!Base)
      continue;
    IRB.CreateAlignedStore(MSV.getShadow(A), Base,
                           kShadowTLSAlignment.value());
  }
  Constant *OverflowSize =
    ConstantInt::get(IRB.getInt64Ty(), OverflowOffset - AArch64VAEndOffset);
  IRB.CreateStore(OverflowSize, MS.VAArgOverflowSizeTLS);
}

/// Compute the shadow address for a given va_arg.
Value *getShadowPtrForVAArgument(Type *Ty, IRBuilder<> &IRB,
                                 unsigned ArgOffset, unsigned ArgSize) {
  // Make sure we don't overflow __msan_va_arg_tls.
  if (ArgOffset + ArgSize > kParamTLSSize)
    return nullptr;
  Value *Base = IRB.CreatePointerCast(MS.VAArgTLS, MS.IntptrTy);
  Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
  return IRB.CreateIntToPtr(Base, PointerType::get(MSV.getShadowTy(Ty), 0),
                            "_msarg");
}

void visitVAStartInst(VAStartInst &I) override {
  IRBuilder<> IRB(&I);
  VAStartInstrumentationList.push_back(&I);
  Value *VAListTag = I.getArgOperand(0);
  Value *ShadowPtr, *OriginPtr;
  const Align Alignment = Align(8);
  std::tie(ShadowPtr, OriginPtr) = MSV.getShadowOriginPtr(
      VAListTag, IRB, IRB.getInt8Ty(), Alignment, /*isStore*/ true);
  IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
                   /* size */ 32, Alignment, false);
}

void visitVACopyInst(VACopyInst &I) override {
  IRBuilder<> IRB(&I);
  VAStartInstrumentationList.push_back(&I);
  Value *VAListTag = I.getArgOperand(0);
  Value *ShadowPtr, *OriginPtr;
  const Align Alignment = Align(8);
  std::tie(ShadowPtr, OriginPtr) = MSV.getShadowOriginPtr(
      VAListTag, IRB, IRB.getInt8Ty(), Alignment, /*isStore*/ true);
  IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
                   /* size */ 32, Alignment, false);
}

// Retrieve a va_list field of 'void*' size.
Value* getVAField64(IRBuilder<> &IRB, Value *VAListTag, int offset) {
  Value *SaveAreaPtrPtr =
    IRB.CreateIntToPtr(
      IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
                    ConstantInt::get(MS.IntptrTy, offset)),
      Type::getInt64PtrTy(*MS.C));
  return IRB.CreateLoad(Type::getInt64Ty(*MS.C), SaveAreaPtrPtr);
}

// Retrieve a va_list field of 'int' size.
Value* getVAField32(IRBuilder<> &IRB, Value *VAListTag, int offset) {
  Value *SaveAreaPtr =
    IRB.CreateIntToPtr(
      IRB.CreateAdd(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
                    ConstantInt::get(MS.IntptrTy, offset)),
      Type::getInt32PtrTy(*MS.C));
  Value *SaveArea32 = IRB.CreateLoad(IRB.getInt32Ty(), SaveAreaPtr);
  return IRB.CreateSExt(SaveArea32, MS.IntptrTy);
}

void finalizeInstrumentation() override {
  assert(!VAArgOverflowSize && !VAArgTLSCopy &&((!VAArgOverflowSize && !VAArgTLSCopy && "finalizeInstrumentation called twice"
) ? static_cast<void> (0) : __assert_fail ("!VAArgOverflowSize && !VAArgTLSCopy && \"finalizeInstrumentation called twice\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 4285, __PRETTY_FUNCTION__))
         "finalizeInstrumentation called twice")((!VAArgOverflowSize && !VAArgTLSCopy && "finalizeInstrumentation called twice"
) ? static_cast<void> (0) : __assert_fail ("!VAArgOverflowSize && !VAArgTLSCopy && \"finalizeInstrumentation called twice\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 4285, __PRETTY_FUNCTION__));
  if (!VAStartInstrumentationList.empty()) {
    // If there is a va_start in this function, make a backup copy of
    // va_arg_tls somewhere in the function entry block.
    IRBuilder<> IRB(MSV.ActualFnStart->getFirstNonPHI());
    VAArgOverflowSize =
        IRB.CreateLoad(IRB.getInt64Ty(), MS.VAArgOverflowSizeTLS);
    Value *CopySize =
      IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, AArch64VAEndOffset),
                    VAArgOverflowSize);
    VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
    IRB.CreateMemCpy(VAArgTLSCopy, Align(8), MS.VAArgTLS, Align(8), CopySize);
  }

  Value *GrArgSize = ConstantInt::get(MS.IntptrTy, kAArch64GrArgSize);
  Value *VrArgSize = ConstantInt::get(MS.IntptrTy, kAArch64VrArgSize);

  // Instrument va_start, copy va_list shadow from the backup copy of
  // the TLS contents.
  for (size_t i = 0, n = VAStartInstrumentationList.size(); i < n; i++) {
    CallInst *OrigInst = VAStartInstrumentationList[i];
    IRBuilder<> IRB(OrigInst->getNextNode());

    Value *VAListTag = OrigInst->getArgOperand(0);

    // The variadic ABI for AArch64 creates two areas to save the incoming
    // argument registers (one for 64-bit general register xn-x7 and another
    // for 128-bit FP/SIMD vn-v7).
    // We need then to propagate the shadow arguments on both regions
    // 'va::__gr_top + va::__gr_offs' and 'va::__vr_top + va::__vr_offs'.
    // The remaning arguments are saved on shadow for 'va::stack'.
    // One caveat is it requires only to propagate the non-named arguments,
    // however on the call site instrumentation 'all' the arguments are
    // saved. So to copy the shadow values from the va_arg TLS array
    // we need to adjust the offset for both GR and VR fields based on
    // the __{gr,vr}_offs value (since they are stores based on incoming
    // named arguments).

    // Read the stack pointer from the va_list.
    Value *StackSaveAreaPtr = getVAField64(IRB, VAListTag, 0);

    // Read both the __gr_top and __gr_off and add them up.
    Value *GrTopSaveAreaPtr = getVAField64(IRB, VAListTag, 8);
    Value *GrOffSaveArea = getVAField32(IRB, VAListTag, 24);

    Value *GrRegSaveAreaPtr = IRB.CreateAdd(GrTopSaveAreaPtr, GrOffSaveArea);

    // Read both the __vr_top and __vr_off and add them up.
    Value *VrTopSaveAreaPtr = getVAField64(IRB, VAListTag, 16);
    Value *VrOffSaveArea = getVAField32(IRB, VAListTag, 28);

    Value *VrRegSaveAreaPtr = IRB.CreateAdd(VrTopSaveAreaPtr, VrOffSaveArea);

    // It does not know how many named arguments is being used and, on the
    // callsite all the arguments were saved.  Since __gr_off is defined as
    // '0 - ((8 - named_gr) * 8)', the idea is to just propagate the variadic
    // argument by ignoring the bytes of shadow from named arguments.
    Value *GrRegSaveAreaShadowPtrOff =
      IRB.CreateAdd(GrArgSize, GrOffSaveArea);

    Value *GrRegSaveAreaShadowPtr =
        MSV.getShadowOriginPtr(GrRegSaveAreaPtr, IRB, IRB.getInt8Ty(),
                               Align(8), /*isStore*/ true)
            .first;

    Value *GrSrcPtr = IRB.CreateInBoundsGEP(IRB.getInt8Ty(), VAArgTLSCopy,
                                            GrRegSaveAreaShadowPtrOff);
    Value *GrCopySize = IRB.CreateSub(GrArgSize, GrRegSaveAreaShadowPtrOff);

    IRB.CreateMemCpy(GrRegSaveAreaShadowPtr, Align(8), GrSrcPtr, Align(8),
                     GrCopySize);

    // Again, but for FP/SIMD values.
    Value *VrRegSaveAreaShadowPtrOff =
        IRB.CreateAdd(VrArgSize, VrOffSaveArea);

    Value *VrRegSaveAreaShadowPtr =
        MSV.getShadowOriginPtr(VrRegSaveAreaPtr, IRB, IRB.getInt8Ty(),
                               Align(8), /*isStore*/ true)
            .first;

    Value *VrSrcPtr = IRB.CreateInBoundsGEP(
      IRB.getInt8Ty(),
      IRB.CreateInBoundsGEP(IRB.getInt8Ty(), VAArgTLSCopy,
                            IRB.getInt32(AArch64VrBegOffset)),
      VrRegSaveAreaShadowPtrOff);
    Value *VrCopySize = IRB.CreateSub(VrArgSize, VrRegSaveAreaShadowPtrOff);

    IRB.CreateMemCpy(VrRegSaveAreaShadowPtr, Align(8), VrSrcPtr, Align(8),
                     VrCopySize);

    // And finally for remaining arguments.
    Value *StackSaveAreaShadowPtr =
        MSV.getShadowOriginPtr(StackSaveAreaPtr, IRB, IRB.getInt8Ty(),
                               Align(16), /*isStore*/ true)
            .first;

    Value *StackSrcPtr =
      IRB.CreateInBoundsGEP(IRB.getInt8Ty(), VAArgTLSCopy,
                            IRB.getInt32(AArch64VAEndOffset));

    IRB.CreateMemCpy(StackSaveAreaShadowPtr, Align(16), StackSrcPtr,
                     Align(16), VAArgOverflowSize);
  }
}
4390};

4392/// PowerPC64-specific implementation of VarArgHelper.
4393struct VarArgPowerPC64Helper : public VarArgHelper {
Function &F;
MemorySanitizer &MS;
MemorySanitizerVisitor &MSV;
Value *VAArgTLSCopy = nullptr;
Value *VAArgSize = nullptr;

SmallVector<CallInst*, 16> VAStartInstrumentationList;

VarArgPowerPC64Helper(Function &F, MemorySanitizer &MS,
                  MemorySanitizerVisitor &MSV) : F(F), MS(MS), MSV(MSV) {}

void visitCallSite(CallSite &CS, IRBuilder<> &IRB) override {
  // For PowerPC, we need to deal with alignment of stack arguments -
  // they are mostly aligned to 8 bytes, but vectors and i128 arrays
  // are aligned to 16 bytes, byvals can be aligned to 8 or 16 bytes,
  // and QPX vectors are aligned to 32 bytes.  For that reason, we
  // compute current offset from stack pointer (which is always properly
  // aligned), and offset for the first vararg, then subtract them.
  unsigned VAArgBase;
  Triple TargetTriple(F.getParent()->getTargetTriple());
  // Parameter save area starts at 48 bytes from frame pointer for ABIv1,
  // and 32 bytes for ABIv2.  This is usually determined by target
  // endianness, but in theory could be overriden by function attribute.
  // For simplicity, we ignore it here (it'd only matter for QPX vectors).
  if (TargetTriple.getArch() == Triple::ppc64)
    VAArgBase = 48;
  else
    VAArgBase = 32;
  unsigned VAArgOffset = VAArgBase;
  const DataLayout &DL = F.getParent()->getDataLayout();
  for (CallSite::arg_iterator ArgIt = CS.arg_begin(), End = CS.arg_end();
       ArgIt != End; ++ArgIt) {
    Value *A = *ArgIt;
    unsigned ArgNo = CS.getArgumentNo(ArgIt);
    bool IsFixed = ArgNo < CS.getFunctionType()->getNumParams();
    bool IsByVal = CS.paramHasAttr(ArgNo, Attribute::ByVal);
    if (IsByVal) {
      assert(A->getType()->isPointerTy())((A->getType()->isPointerTy()) ? static_cast<void>
 (0) : __assert_fail ("A->getType()->isPointerTy()", "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 4431, __PRETTY_FUNCTION__));
      Type *RealTy = A->getType()->getPointerElementType();
      uint64_t ArgSize = DL.getTypeAllocSize(RealTy);
      uint64_t ArgAlign = CS.getParamAlignment(ArgNo);
      if (ArgAlign < 8)
        ArgAlign = 8;
      VAArgOffset = alignTo(VAArgOffset, ArgAlign);
      if (!IsFixed) {
        Value *Base = getShadowPtrForVAArgument(
            RealTy, IRB, VAArgOffset - VAArgBase, ArgSize);
        if (Base) {
          Value *AShadowPtr, *AOriginPtr;
          std::tie(AShadowPtr, AOriginPtr) =
              MSV.getShadowOriginPtr(A, IRB, IRB.getInt8Ty(),
                                     kShadowTLSAlignment, /*isStore*/ false);

          IRB.CreateMemCpy(Base, kShadowTLSAlignment, AShadowPtr,
                           kShadowTLSAlignment, ArgSize);
        }
      }
      VAArgOffset += alignTo(ArgSize, 8);
    } else {
      Value *Base;
      uint64_t ArgSize = DL.getTypeAllocSize(A->getType());
      uint64_t ArgAlign = 8;
      if (A->getType()->isArrayTy()) {
        // Arrays are aligned to element size, except for long double
        // arrays, which are aligned to 8 bytes.
        Type *ElementTy = A->getType()->getArrayElementType();
        if (!ElementTy->isPPC_FP128Ty())
          ArgAlign = DL.getTypeAllocSize(ElementTy);
      } else if (A->getType()->isVectorTy()) {
        // Vectors are naturally aligned.
        ArgAlign = DL.getTypeAllocSize(A->getType());
      }
      if (ArgAlign < 8)
        ArgAlign = 8;
      VAArgOffset = alignTo(VAArgOffset, ArgAlign);
      if (DL.isBigEndian()) {
        // Adjusting the shadow for argument with size < 8 to match the placement
        // of bits in big endian system
        if (ArgSize < 8)
          VAArgOffset += (8 - ArgSize);
      }
      if (!IsFixed) {
        Base = getShadowPtrForVAArgument(A->getType(), IRB,
                                         VAArgOffset - VAArgBase, ArgSize);
        if (Base)
          IRB.CreateAlignedStore(MSV.getShadow(A), Base,
                                 kShadowTLSAlignment.value());
      }
      VAArgOffset += ArgSize;
      VAArgOffset = alignTo(VAArgOffset, 8);
    }
    if (IsFixed)
      VAArgBase = VAArgOffset;
  }

  Constant *TotalVAArgSize = ConstantInt::get(IRB.getInt64Ty(),
                                              VAArgOffset - VAArgBase);
  // Here using VAArgOverflowSizeTLS as VAArgSizeTLS to avoid creation of
  // a new class member i.e. it is the total size of all VarArgs.
  IRB.CreateStore(TotalVAArgSize, MS.VAArgOverflowSizeTLS);
}

/// Compute the shadow address for a given va_arg.
Value *getShadowPtrForVAArgument(Type *Ty, IRBuilder<> &IRB,
                                 unsigned ArgOffset, unsigned ArgSize) {
  // Make sure we don't overflow __msan_va_arg_tls.
  if (ArgOffset + ArgSize > kParamTLSSize)
    return nullptr;
  Value *Base = IRB.CreatePointerCast(MS.VAArgTLS, MS.IntptrTy);
  Base = IRB.CreateAdd(Base, ConstantInt::get(MS.IntptrTy, ArgOffset));
  return IRB.CreateIntToPtr(Base, PointerType::get(MSV.getShadowTy(Ty), 0),
                            "_msarg");
}

void visitVAStartInst(VAStartInst &I) override {
  IRBuilder<> IRB(&I);
  VAStartInstrumentationList.push_back(&I);
  Value *VAListTag = I.getArgOperand(0);
  Value *ShadowPtr, *OriginPtr;
  const Align Alignment = Align(8);
  std::tie(ShadowPtr, OriginPtr) = MSV.getShadowOriginPtr(
      VAListTag, IRB, IRB.getInt8Ty(), Alignment, /*isStore*/ true);
  IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
                   /* size */ 8, Alignment, false);
}

void visitVACopyInst(VACopyInst &I) override {
  IRBuilder<> IRB(&I);
  Value *VAListTag = I.getArgOperand(0);
  Value *ShadowPtr, *OriginPtr;
  const Align Alignment = Align(8);
  std::tie(ShadowPtr, OriginPtr) = MSV.getShadowOriginPtr(
      VAListTag, IRB, IRB.getInt8Ty(), Alignment, /*isStore*/ true);
  // Unpoison the whole __va_list_tag.
  // FIXME: magic ABI constants.
  IRB.CreateMemSet(ShadowPtr, Constant::getNullValue(IRB.getInt8Ty()),
                   /* size */ 8, Alignment, false);
}

void finalizeInstrumentation() override {
  assert(!VAArgSize && !VAArgTLSCopy &&((!VAArgSize && !VAArgTLSCopy && "finalizeInstrumentation called twice"
) ? static_cast<void> (0) : __assert_fail ("!VAArgSize && !VAArgTLSCopy && \"finalizeInstrumentation called twice\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 4535, __PRETTY_FUNCTION__))
         "finalizeInstrumentation called twice")((!VAArgSize && !VAArgTLSCopy && "finalizeInstrumentation called twice"
) ? static_cast<void> (0) : __assert_fail ("!VAArgSize && !VAArgTLSCopy && \"finalizeInstrumentation called twice\""
, "/build/llvm-toolchain-snapshot-10~++20200107111111+051c4d5b7bc/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp"
, 4535, __PRETTY_FUNCTION__));
  IRBuilder<> IRB(MSV.ActualFnStart->getFirstNonPHI());
  VAArgSize = IRB.CreateLoad(IRB.getInt64Ty(), MS.VAArgOverflowSizeTLS);
  Value *CopySize = IRB.CreateAdd(ConstantInt::get(MS.IntptrTy, 0),
                                  VAArgSize);

  if (!VAStartInstrumentationList.empty()) {
    // If there is a va_start in this function, make a backup copy of
    // va_arg_tls somewhere in the function entry block.
    VAArgTLSCopy = IRB.CreateAlloca(Type::getInt8Ty(*MS.C), CopySize);
    IRB.CreateMemCpy(VAArgTLSCopy, Align(8), MS.VAArgTLS, Align(8), CopySize);
  }

  // Instrument va_start.
  // Copy va_list shadow from the backup copy of the TLS contents.
  for (size_t i = 0, n = VAStartInstrumentationList.size(); i < n; i++) {
    CallInst *OrigInst = VAStartInstrumentationList[i];
    IRBuilder<> IRB(OrigInst->getNextNode());
    Value *VAListTag = OrigInst->getArgOperand(0);
    Type *RegSaveAreaPtrTy = Type::getInt64PtrTy(*MS.C);
    Value *RegSaveAreaPtrPtr =
        IRB.CreateIntToPtr(IRB.CreatePtrToInt(VAListTag, MS.IntptrTy),
                           PointerType::get(RegSaveAreaPtrTy, 0));
    Value *RegSaveAreaPtr =
        IRB.CreateLoad(RegSaveAreaPtrTy, RegSaveAreaPtrPtr);
    Value *RegSaveAreaShadowPtr, *RegSaveAreaOriginPtr;
    const Align Alignment = Align(8);
    std::tie(RegSaveAreaShadowPtr, RegSaveAreaOriginPtr) =
        MSV.getShadowOriginPtr(RegSaveAreaPtr, IRB, IRB.getInt8Ty(),
                               Alignment, /*isStore*/ true);
    IRB.CreateMemCpy(RegSaveAreaShadowPtr, Alignment, VAArgTLSCopy, Alignment,
                     CopySize);
  }
}
4569};

4571/// A no-op implementation of VarArgHelper.
4572struct VarArgNoOpHelper : public VarArgHelper {
VarArgNoOpHelper(Function &F, MemorySanitizer &MS,
                 MemorySanitizerVisitor &MSV) {}

void visitCallSite(CallSite &CS, IRBuilder<> &IRB) override {}

void visitVAStartInst(VAStartInst &I) override {}

void visitVACopyInst(VACopyInst &I) override {}

void finalizeInstrumentation() override {}
4583};

4585} // end anonymous namespace

4587static VarArgHelper *CreateVarArgHelper(Function &Func, MemorySanitizer &Msan,
                                      MemorySanitizerVisitor &Visitor) {
// VarArg handling is only implemented on AMD64. False positives are possible
// on other platforms.
Triple TargetTriple(Func.getParent()->getTargetTriple());
if (TargetTriple.getArch() == Triple::x86_64)
  return new VarArgAMD64Helper(Func, Msan, Visitor);
else if (TargetTriple.isMIPS64())
  return new VarArgMIPS64Helper(Func, Msan, Visitor);
else if (TargetTriple.getArch() == Triple::aarch64)
  return new VarArgAArch64Helper(Func, Msan, Visitor);
else if (TargetTriple.getArch() == Triple::ppc64 ||
         TargetTriple.getArch() == Triple::ppc64le)
  return new VarArgPowerPC64Helper(Func, Msan, Visitor);
else
  return new VarArgNoOpHelper(Func, Msan, Visitor);
4603}

4605bool MemorySanitizer::sanitizeFunction(Function &F, TargetLibraryInfo &TLI) {
if (!CompileKernel && F.getName() == kMsanModuleCtorName)
  return false;

MemorySanitizerVisitor Visitor(F, *this, TLI);

// Clear out readonly/readnone attributes.
AttrBuilder B;
B.addAttribute(Attribute::ReadOnly)
    .addAttribute(Attribute::ReadNone)
    .addAttribute(Attribute::WriteOnly)
    .addAttribute(Attribute::ArgMemOnly)
    .addAttribute(Attribute::Speculatable);
F.removeAttributes(AttributeList::FunctionIndex, B);

return Visitor.runOnFunction();
4621}