LLVM  6.0.0svn
AddressSanitizer.cpp
Go to the documentation of this file.
1 //===-- AddressSanitizer.cpp - memory error detector ------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file is a part of AddressSanitizer, an address sanity checker.
11 // Details of the algorithm:
12 // http://code.google.com/p/address-sanitizer/wiki/AddressSanitizerAlgorithm
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "llvm/ADT/ArrayRef.h"
17 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/SetVector.h"
20 #include "llvm/ADT/SmallSet.h"
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/ADT/Statistic.h"
23 #include "llvm/ADT/StringExtras.h"
24 #include "llvm/ADT/Triple.h"
25 #include "llvm/ADT/Twine.h"
29 #include "llvm/IR/Argument.h"
30 #include "llvm/IR/CallSite.h"
31 #include "llvm/IR/DIBuilder.h"
32 #include "llvm/IR/DataLayout.h"
33 #include "llvm/IR/Dominators.h"
34 #include "llvm/IR/Function.h"
35 #include "llvm/IR/IRBuilder.h"
36 #include "llvm/IR/InlineAsm.h"
37 #include "llvm/IR/InstVisitor.h"
38 #include "llvm/IR/IntrinsicInst.h"
39 #include "llvm/IR/LLVMContext.h"
40 #include "llvm/IR/MDBuilder.h"
41 #include "llvm/IR/Module.h"
42 #include "llvm/IR/Type.h"
43 #include "llvm/MC/MCSectionMachO.h"
45 #include "llvm/Support/DataTypes.h"
46 #include "llvm/Support/Debug.h"
47 #include "llvm/Support/Endian.h"
52 #include "llvm/Transforms/Scalar.h"
59 #include <algorithm>
60 #include <iomanip>
61 #include <limits>
62 #include <sstream>
63 #include <string>
64 #include <system_error>
65 
66 using namespace llvm;
67 
68 #define DEBUG_TYPE "asan"
69 
70 static const uint64_t kDefaultShadowScale = 3;
71 static const uint64_t kDefaultShadowOffset32 = 1ULL << 29;
72 static const uint64_t kDefaultShadowOffset64 = 1ULL << 44;
73 static const uint64_t kDynamicShadowSentinel = ~(uint64_t)0;
74 static const uint64_t kIOSShadowOffset32 = 1ULL << 30;
75 static const uint64_t kIOSSimShadowOffset32 = 1ULL << 30;
77 static const uint64_t kSmallX86_64ShadowOffset = 0x7FFF8000; // < 2G.
78 static const uint64_t kLinuxKasan_ShadowOffset64 = 0xdffffc0000000000;
79 static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 41;
80 static const uint64_t kSystemZ_ShadowOffset64 = 1ULL << 52;
81 static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa0000;
82 static const uint64_t kMIPS64_ShadowOffset64 = 1ULL << 37;
83 static const uint64_t kAArch64_ShadowOffset64 = 1ULL << 36;
84 static const uint64_t kFreeBSD_ShadowOffset32 = 1ULL << 30;
85 static const uint64_t kFreeBSD_ShadowOffset64 = 1ULL << 46;
86 static const uint64_t kNetBSD_ShadowOffset64 = 1ULL << 46;
87 static const uint64_t kPS4CPU_ShadowOffset64 = 1ULL << 40;
88 static const uint64_t kWindowsShadowOffset32 = 3ULL << 28;
89 // The shadow memory space is dynamically allocated.
91 
92 static const size_t kMinStackMallocSize = 1 << 6; // 64B
93 static const size_t kMaxStackMallocSize = 1 << 16; // 64K
94 static const uintptr_t kCurrentStackFrameMagic = 0x41B58AB3;
95 static const uintptr_t kRetiredStackFrameMagic = 0x45E0360E;
96 
97 static const char *const kAsanModuleCtorName = "asan.module_ctor";
98 static const char *const kAsanModuleDtorName = "asan.module_dtor";
99 static const uint64_t kAsanCtorAndDtorPriority = 1;
100 static const char *const kAsanReportErrorTemplate = "__asan_report_";
101 static const char *const kAsanRegisterGlobalsName = "__asan_register_globals";
102 static const char *const kAsanUnregisterGlobalsName =
103  "__asan_unregister_globals";
104 static const char *const kAsanRegisterImageGlobalsName =
105  "__asan_register_image_globals";
106 static const char *const kAsanUnregisterImageGlobalsName =
107  "__asan_unregister_image_globals";
108 static const char *const kAsanRegisterElfGlobalsName =
109  "__asan_register_elf_globals";
110 static const char *const kAsanUnregisterElfGlobalsName =
111  "__asan_unregister_elf_globals";
112 static const char *const kAsanPoisonGlobalsName = "__asan_before_dynamic_init";
113 static const char *const kAsanUnpoisonGlobalsName = "__asan_after_dynamic_init";
114 static const char *const kAsanInitName = "__asan_init";
115 static const char *const kAsanVersionCheckName =
116  "__asan_version_mismatch_check_v8";
117 static const char *const kAsanPtrCmp = "__sanitizer_ptr_cmp";
118 static const char *const kAsanPtrSub = "__sanitizer_ptr_sub";
119 static const char *const kAsanHandleNoReturnName = "__asan_handle_no_return";
120 static const int kMaxAsanStackMallocSizeClass = 10;
121 static const char *const kAsanStackMallocNameTemplate = "__asan_stack_malloc_";
122 static const char *const kAsanStackFreeNameTemplate = "__asan_stack_free_";
123 static const char *const kAsanGenPrefix = "__asan_gen_";
124 static const char *const kODRGenPrefix = "__odr_asan_gen_";
125 static const char *const kSanCovGenPrefix = "__sancov_gen_";
126 static const char *const kAsanSetShadowPrefix = "__asan_set_shadow_";
127 static const char *const kAsanPoisonStackMemoryName =
128  "__asan_poison_stack_memory";
129 static const char *const kAsanUnpoisonStackMemoryName =
130  "__asan_unpoison_stack_memory";
131 
132 // ASan version script has __asan_* wildcard. Triple underscore prevents a
133 // linker (gold) warning about attempting to export a local symbol.
134 static const char *const kAsanGlobalsRegisteredFlagName =
135  "___asan_globals_registered";
136 
137 static const char *const kAsanOptionDetectUseAfterReturn =
138  "__asan_option_detect_stack_use_after_return";
139 
140 static const char *const kAsanShadowMemoryDynamicAddress =
141  "__asan_shadow_memory_dynamic_address";
142 
143 static const char *const kAsanAllocaPoison = "__asan_alloca_poison";
144 static const char *const kAsanAllocasUnpoison = "__asan_allocas_unpoison";
145 
146 // Accesses sizes are powers of two: 1, 2, 4, 8, 16.
147 static const size_t kNumberOfAccessSizes = 5;
148 
149 static const unsigned kAllocaRzSize = 32;
150 
151 // Command-line flags.
153  "asan-kernel", cl::desc("Enable KernelAddressSanitizer instrumentation"),
154  cl::Hidden, cl::init(false));
155 static cl::opt<bool> ClRecover(
156  "asan-recover",
157  cl::desc("Enable recovery mode (continue-after-error)."),
158  cl::Hidden, cl::init(false));
159 
160 // This flag may need to be replaced with -f[no-]asan-reads.
161 static cl::opt<bool> ClInstrumentReads("asan-instrument-reads",
162  cl::desc("instrument read instructions"),
163  cl::Hidden, cl::init(true));
165  "asan-instrument-writes", cl::desc("instrument write instructions"),
166  cl::Hidden, cl::init(true));
168  "asan-instrument-atomics",
169  cl::desc("instrument atomic instructions (rmw, cmpxchg)"), cl::Hidden,
170  cl::init(true));
172  "asan-always-slow-path",
173  cl::desc("use instrumentation with slow path for all accesses"), cl::Hidden,
174  cl::init(false));
176  "asan-force-dynamic-shadow",
177  cl::desc("Load shadow address into a local variable for each function"),
178  cl::Hidden, cl::init(false));
179 
180 // This flag limits the number of instructions to be instrumented
181 // in any given BB. Normally, this should be set to unlimited (INT_MAX),
182 // but due to http://llvm.org/bugs/show_bug.cgi?id=12652 we temporary
183 // set it to 10000.
185  "asan-max-ins-per-bb", cl::init(10000),
186  cl::desc("maximal number of instructions to instrument in any given BB"),
187  cl::Hidden);
188 // This flag may need to be replaced with -f[no]asan-stack.
189 static cl::opt<bool> ClStack("asan-stack", cl::desc("Handle stack memory"),
190  cl::Hidden, cl::init(true));
192  "asan-max-inline-poisoning-size",
193  cl::desc(
194  "Inline shadow poisoning for blocks up to the given size in bytes."),
195  cl::Hidden, cl::init(64));
196 static cl::opt<bool> ClUseAfterReturn("asan-use-after-return",
197  cl::desc("Check stack-use-after-return"),
198  cl::Hidden, cl::init(true));
199 static cl::opt<bool> ClRedzoneByvalArgs("asan-redzone-byval-args",
200  cl::desc("Create redzones for byval "
201  "arguments (extra copy "
202  "required)"), cl::Hidden,
203  cl::init(true));
204 static cl::opt<bool> ClUseAfterScope("asan-use-after-scope",
205  cl::desc("Check stack-use-after-scope"),
206  cl::Hidden, cl::init(false));
207 // This flag may need to be replaced with -f[no]asan-globals.
208 static cl::opt<bool> ClGlobals("asan-globals",
209  cl::desc("Handle global objects"), cl::Hidden,
210  cl::init(true));
211 static cl::opt<bool> ClInitializers("asan-initialization-order",
212  cl::desc("Handle C++ initializer order"),
213  cl::Hidden, cl::init(true));
215  "asan-detect-invalid-pointer-pair",
216  cl::desc("Instrument <, <=, >, >=, - with pointer operands"), cl::Hidden,
217  cl::init(false));
219  "asan-realign-stack",
220  cl::desc("Realign stack to the value of this flag (power of two)"),
221  cl::Hidden, cl::init(32));
223  "asan-instrumentation-with-call-threshold",
224  cl::desc(
225  "If the function being instrumented contains more than "
226  "this number of memory accesses, use callbacks instead of "
227  "inline checks (-1 means never use callbacks)."),
228  cl::Hidden, cl::init(7000));
230  "asan-memory-access-callback-prefix",
231  cl::desc("Prefix for memory access callbacks"), cl::Hidden,
232  cl::init("__asan_"));
233 static cl::opt<bool>
234  ClInstrumentDynamicAllocas("asan-instrument-dynamic-allocas",
235  cl::desc("instrument dynamic allocas"),
236  cl::Hidden, cl::init(true));
238  "asan-skip-promotable-allocas",
239  cl::desc("Do not instrument promotable allocas"), cl::Hidden,
240  cl::init(true));
241 
242 // These flags allow to change the shadow mapping.
243 // The shadow mapping looks like
244 // Shadow = (Mem >> scale) + offset
245 static cl::opt<int> ClMappingScale("asan-mapping-scale",
246  cl::desc("scale of asan shadow mapping"),
247  cl::Hidden, cl::init(0));
249  "asan-mapping-offset",
250  cl::desc("offset of asan shadow mapping [EXPERIMENTAL]"), cl::Hidden,
251  cl::init(0));
252 
253 // Optimization flags. Not user visible, used mostly for testing
254 // and benchmarking the tool.
255 static cl::opt<bool> ClOpt("asan-opt", cl::desc("Optimize instrumentation"),
256  cl::Hidden, cl::init(true));
258  "asan-opt-same-temp", cl::desc("Instrument the same temp just once"),
259  cl::Hidden, cl::init(true));
260 static cl::opt<bool> ClOptGlobals("asan-opt-globals",
261  cl::desc("Don't instrument scalar globals"),
262  cl::Hidden, cl::init(true));
264  "asan-opt-stack", cl::desc("Don't instrument scalar stack variables"),
265  cl::Hidden, cl::init(false));
266 
268  "asan-stack-dynamic-alloca",
269  cl::desc("Use dynamic alloca to represent stack variables"), cl::Hidden,
270  cl::init(true));
271 
273  "asan-force-experiment",
274  cl::desc("Force optimization experiment (for testing)"), cl::Hidden,
275  cl::init(0));
276 
277 static cl::opt<bool>
278  ClUsePrivateAliasForGlobals("asan-use-private-alias",
279  cl::desc("Use private aliases for global"
280  " variables"),
281  cl::Hidden, cl::init(false));
282 
283 static cl::opt<bool>
284  ClUseGlobalsGC("asan-globals-live-support",
285  cl::desc("Use linker features to support dead "
286  "code stripping of globals"),
287  cl::Hidden, cl::init(true));
288 
289 // This is on by default even though there is a bug in gold:
290 // https://sourceware.org/bugzilla/show_bug.cgi?id=19002
291 static cl::opt<bool>
292  ClWithComdat("asan-with-comdat",
293  cl::desc("Place ASan constructors in comdat sections"),
294  cl::Hidden, cl::init(true));
295 
296 // Debug flags.
297 static cl::opt<int> ClDebug("asan-debug", cl::desc("debug"), cl::Hidden,
298  cl::init(0));
299 static cl::opt<int> ClDebugStack("asan-debug-stack", cl::desc("debug stack"),
300  cl::Hidden, cl::init(0));
301 static cl::opt<std::string> ClDebugFunc("asan-debug-func", cl::Hidden,
302  cl::desc("Debug func"));
303 static cl::opt<int> ClDebugMin("asan-debug-min", cl::desc("Debug min inst"),
304  cl::Hidden, cl::init(-1));
305 static cl::opt<int> ClDebugMax("asan-debug-max", cl::desc("Debug max inst"),
306  cl::Hidden, cl::init(-1));
307 
308 STATISTIC(NumInstrumentedReads, "Number of instrumented reads");
309 STATISTIC(NumInstrumentedWrites, "Number of instrumented writes");
310 STATISTIC(NumOptimizedAccessesToGlobalVar,
311  "Number of optimized accesses to global vars");
312 STATISTIC(NumOptimizedAccessesToStackVar,
313  "Number of optimized accesses to stack vars");
314 
315 namespace {
316 /// Frontend-provided metadata for source location.
317 struct LocationMetadata {
318  StringRef Filename;
319  int LineNo;
320  int ColumnNo;
321 
322  LocationMetadata() : Filename(), LineNo(0), ColumnNo(0) {}
323 
324  bool empty() const { return Filename.empty(); }
325 
326  void parse(MDNode *MDN) {
327  assert(MDN->getNumOperands() == 3);
328  MDString *DIFilename = cast<MDString>(MDN->getOperand(0));
329  Filename = DIFilename->getString();
330  LineNo =
331  mdconst::extract<ConstantInt>(MDN->getOperand(1))->getLimitedValue();
332  ColumnNo =
333  mdconst::extract<ConstantInt>(MDN->getOperand(2))->getLimitedValue();
334  }
335 };
336 
337 /// Frontend-provided metadata for global variables.
338 class GlobalsMetadata {
339  public:
340  struct Entry {
341  Entry() : SourceLoc(), Name(), IsDynInit(false), IsBlacklisted(false) {}
342  LocationMetadata SourceLoc;
343  StringRef Name;
344  bool IsDynInit;
345  bool IsBlacklisted;
346  };
347 
348  GlobalsMetadata() : inited_(false) {}
349 
350  void reset() {
351  inited_ = false;
352  Entries.clear();
353  }
354 
355  void init(Module &M) {
356  assert(!inited_);
357  inited_ = true;
358  NamedMDNode *Globals = M.getNamedMetadata("llvm.asan.globals");
359  if (!Globals) return;
360  for (auto MDN : Globals->operands()) {
361  // Metadata node contains the global and the fields of "Entry".
362  assert(MDN->getNumOperands() == 5);
363  auto *GV = mdconst::extract_or_null<GlobalVariable>(MDN->getOperand(0));
364  // The optimizer may optimize away a global entirely.
365  if (!GV) continue;
366  // We can already have an entry for GV if it was merged with another
367  // global.
368  Entry &E = Entries[GV];
369  if (auto *Loc = cast_or_null<MDNode>(MDN->getOperand(1)))
370  E.SourceLoc.parse(Loc);
371  if (auto *Name = cast_or_null<MDString>(MDN->getOperand(2)))
372  E.Name = Name->getString();
373  ConstantInt *IsDynInit =
374  mdconst::extract<ConstantInt>(MDN->getOperand(3));
375  E.IsDynInit |= IsDynInit->isOne();
376  ConstantInt *IsBlacklisted =
377  mdconst::extract<ConstantInt>(MDN->getOperand(4));
378  E.IsBlacklisted |= IsBlacklisted->isOne();
379  }
380  }
381 
382  /// Returns metadata entry for a given global.
383  Entry get(GlobalVariable *G) const {
384  auto Pos = Entries.find(G);
385  return (Pos != Entries.end()) ? Pos->second : Entry();
386  }
387 
388  private:
389  bool inited_;
391 };
392 
393 /// This struct defines the shadow mapping using the rule:
394 /// shadow = (mem >> Scale) ADD-or-OR Offset.
395 struct ShadowMapping {
396  int Scale;
397  uint64_t Offset;
398  bool OrShadowOffset;
399 };
400 
401 static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize,
402  bool IsKasan) {
403  bool IsAndroid = TargetTriple.isAndroid();
404  bool IsIOS = TargetTriple.isiOS() || TargetTriple.isWatchOS();
405  bool IsFreeBSD = TargetTriple.isOSFreeBSD();
406  bool IsNetBSD = TargetTriple.isOSNetBSD();
407  bool IsPS4CPU = TargetTriple.isPS4CPU();
408  bool IsLinux = TargetTriple.isOSLinux();
409  bool IsPPC64 = TargetTriple.getArch() == llvm::Triple::ppc64 ||
410  TargetTriple.getArch() == llvm::Triple::ppc64le;
411  bool IsSystemZ = TargetTriple.getArch() == llvm::Triple::systemz;
412  bool IsX86 = TargetTriple.getArch() == llvm::Triple::x86;
413  bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64;
414  bool IsMIPS32 = TargetTriple.getArch() == llvm::Triple::mips ||
415  TargetTriple.getArch() == llvm::Triple::mipsel;
416  bool IsMIPS64 = TargetTriple.getArch() == llvm::Triple::mips64 ||
417  TargetTriple.getArch() == llvm::Triple::mips64el;
418  bool IsAArch64 = TargetTriple.getArch() == llvm::Triple::aarch64;
419  bool IsWindows = TargetTriple.isOSWindows();
420  bool IsFuchsia = TargetTriple.isOSFuchsia();
421 
422  ShadowMapping Mapping;
423 
424  if (LongSize == 32) {
425  // Android is always PIE, which means that the beginning of the address
426  // space is always available.
427  if (IsAndroid)
428  Mapping.Offset = 0;
429  else if (IsMIPS32)
430  Mapping.Offset = kMIPS32_ShadowOffset32;
431  else if (IsFreeBSD)
432  Mapping.Offset = kFreeBSD_ShadowOffset32;
433  else if (IsIOS)
434  // If we're targeting iOS and x86, the binary is built for iOS simulator.
435  Mapping.Offset = IsX86 ? kIOSSimShadowOffset32 : kIOSShadowOffset32;
436  else if (IsWindows)
437  Mapping.Offset = kWindowsShadowOffset32;
438  else
439  Mapping.Offset = kDefaultShadowOffset32;
440  } else { // LongSize == 64
441  // Fuchsia is always PIE, which means that the beginning of the address
442  // space is always available.
443  if (IsFuchsia)
444  Mapping.Offset = 0;
445  else if (IsPPC64)
446  Mapping.Offset = kPPC64_ShadowOffset64;
447  else if (IsSystemZ)
448  Mapping.Offset = kSystemZ_ShadowOffset64;
449  else if (IsFreeBSD)
450  Mapping.Offset = kFreeBSD_ShadowOffset64;
451  else if (IsNetBSD)
452  Mapping.Offset = kNetBSD_ShadowOffset64;
453  else if (IsPS4CPU)
454  Mapping.Offset = kPS4CPU_ShadowOffset64;
455  else if (IsLinux && IsX86_64) {
456  if (IsKasan)
457  Mapping.Offset = kLinuxKasan_ShadowOffset64;
458  else
459  Mapping.Offset = kSmallX86_64ShadowOffset;
460  } else if (IsWindows && IsX86_64) {
461  Mapping.Offset = kWindowsShadowOffset64;
462  } else if (IsMIPS64)
463  Mapping.Offset = kMIPS64_ShadowOffset64;
464  else if (IsIOS)
465  // If we're targeting iOS and x86, the binary is built for iOS simulator.
466  // We are using dynamic shadow offset on the 64-bit devices.
467  Mapping.Offset =
469  else if (IsAArch64)
470  Mapping.Offset = kAArch64_ShadowOffset64;
471  else
472  Mapping.Offset = kDefaultShadowOffset64;
473  }
474 
475  if (ClForceDynamicShadow) {
476  Mapping.Offset = kDynamicShadowSentinel;
477  }
478 
479  Mapping.Scale = kDefaultShadowScale;
480  if (ClMappingScale.getNumOccurrences() > 0) {
481  Mapping.Scale = ClMappingScale;
482  }
483 
484  if (ClMappingOffset.getNumOccurrences() > 0) {
485  Mapping.Offset = ClMappingOffset;
486  }
487 
488  // OR-ing shadow offset if more efficient (at least on x86) if the offset
489  // is a power of two, but on ppc64 we have to use add since the shadow
490  // offset is not necessary 1/8-th of the address space. On SystemZ,
491  // we could OR the constant in a single instruction, but it's more
492  // efficient to load it once and use indexed addressing.
493  Mapping.OrShadowOffset = !IsAArch64 && !IsPPC64 && !IsSystemZ && !IsPS4CPU &&
494  !(Mapping.Offset & (Mapping.Offset - 1)) &&
495  Mapping.Offset != kDynamicShadowSentinel;
496 
497  return Mapping;
498 }
499 
500 static size_t RedzoneSizeForScale(int MappingScale) {
501  // Redzone used for stack and globals is at least 32 bytes.
502  // For scales 6 and 7, the redzone has to be 64 and 128 bytes respectively.
503  return std::max(32U, 1U << MappingScale);
504 }
505 
506 /// AddressSanitizer: instrument the code in module to find memory bugs.
507 struct AddressSanitizer : public FunctionPass {
508  explicit AddressSanitizer(bool CompileKernel = false, bool Recover = false,
509  bool UseAfterScope = false)
510  : FunctionPass(ID), CompileKernel(CompileKernel || ClEnableKasan),
511  Recover(Recover || ClRecover),
512  UseAfterScope(UseAfterScope || ClUseAfterScope),
513  LocalDynamicShadow(nullptr) {
515  }
516  StringRef getPassName() const override {
517  return "AddressSanitizerFunctionPass";
518  }
519  void getAnalysisUsage(AnalysisUsage &AU) const override {
522  }
523  uint64_t getAllocaSizeInBytes(const AllocaInst &AI) const {
524  uint64_t ArraySize = 1;
525  if (AI.isArrayAllocation()) {
526  const ConstantInt *CI = dyn_cast<ConstantInt>(AI.getArraySize());
527  assert(CI && "non-constant array size");
528  ArraySize = CI->getZExtValue();
529  }
530  Type *Ty = AI.getAllocatedType();
531  uint64_t SizeInBytes =
533  return SizeInBytes * ArraySize;
534  }
535  /// Check if we want (and can) handle this alloca.
536  bool isInterestingAlloca(const AllocaInst &AI);
537 
538  /// If it is an interesting memory access, return the PointerOperand
539  /// and set IsWrite/Alignment. Otherwise return nullptr.
540  /// MaybeMask is an output parameter for the mask Value, if we're looking at a
541  /// masked load/store.
542  Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite,
543  uint64_t *TypeSize, unsigned *Alignment,
544  Value **MaybeMask = nullptr);
545  void instrumentMop(ObjectSizeOffsetVisitor &ObjSizeVis, Instruction *I,
546  bool UseCalls, const DataLayout &DL);
547  void instrumentPointerComparisonOrSubtraction(Instruction *I);
548  void instrumentAddress(Instruction *OrigIns, Instruction *InsertBefore,
549  Value *Addr, uint32_t TypeSize, bool IsWrite,
550  Value *SizeArgument, bool UseCalls, uint32_t Exp);
551  void instrumentUnusualSizeOrAlignment(Instruction *I,
552  Instruction *InsertBefore, Value *Addr,
553  uint32_t TypeSize, bool IsWrite,
554  Value *SizeArgument, bool UseCalls,
555  uint32_t Exp);
556  Value *createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
557  Value *ShadowValue, uint32_t TypeSize);
558  Instruction *generateCrashCode(Instruction *InsertBefore, Value *Addr,
559  bool IsWrite, size_t AccessSizeIndex,
560  Value *SizeArgument, uint32_t Exp);
561  void instrumentMemIntrinsic(MemIntrinsic *MI);
562  Value *memToShadow(Value *Shadow, IRBuilder<> &IRB);
563  bool runOnFunction(Function &F) override;
564  bool maybeInsertAsanInitAtFunctionEntry(Function &F);
565  void maybeInsertDynamicShadowAtFunctionEntry(Function &F);
566  void markEscapedLocalAllocas(Function &F);
567  bool doInitialization(Module &M) override;
568  bool doFinalization(Module &M) override;
569  static char ID; // Pass identification, replacement for typeid
570 
571  DominatorTree &getDominatorTree() const { return *DT; }
572 
573  private:
574  void initializeCallbacks(Module &M);
575 
576  bool LooksLikeCodeInBug11395(Instruction *I);
577  bool GlobalIsLinkerInitialized(GlobalVariable *G);
578  bool isSafeAccess(ObjectSizeOffsetVisitor &ObjSizeVis, Value *Addr,
579  uint64_t TypeSize) const;
580 
581  /// Helper to cleanup per-function state.
582  struct FunctionStateRAII {
583  AddressSanitizer *Pass;
584  FunctionStateRAII(AddressSanitizer *Pass) : Pass(Pass) {
585  assert(Pass->ProcessedAllocas.empty() &&
586  "last pass forgot to clear cache");
587  assert(!Pass->LocalDynamicShadow);
588  }
589  ~FunctionStateRAII() {
590  Pass->LocalDynamicShadow = nullptr;
591  Pass->ProcessedAllocas.clear();
592  }
593  };
594 
595  LLVMContext *C;
596  Triple TargetTriple;
597  int LongSize;
598  bool CompileKernel;
599  bool Recover;
600  bool UseAfterScope;
601  Type *IntptrTy;
602  ShadowMapping Mapping;
603  DominatorTree *DT;
604  Function *AsanHandleNoReturnFunc;
605  Function *AsanPtrCmpFunction, *AsanPtrSubFunction;
606  // This array is indexed by AccessIsWrite, Experiment and log2(AccessSize).
607  Function *AsanErrorCallback[2][2][kNumberOfAccessSizes];
608  Function *AsanMemoryAccessCallback[2][2][kNumberOfAccessSizes];
609  // This array is indexed by AccessIsWrite and Experiment.
610  Function *AsanErrorCallbackSized[2][2];
611  Function *AsanMemoryAccessCallbackSized[2][2];
612  Function *AsanMemmove, *AsanMemcpy, *AsanMemset;
613  InlineAsm *EmptyAsm;
614  Value *LocalDynamicShadow;
615  GlobalsMetadata GlobalsMD;
616  DenseMap<const AllocaInst *, bool> ProcessedAllocas;
617 
618  friend struct FunctionStackPoisoner;
619 };
620 
621 class AddressSanitizerModule : public ModulePass {
622 public:
623  explicit AddressSanitizerModule(bool CompileKernel = false,
624  bool Recover = false,
625  bool UseGlobalsGC = true)
626  : ModulePass(ID), CompileKernel(CompileKernel || ClEnableKasan),
627  Recover(Recover || ClRecover),
628  UseGlobalsGC(UseGlobalsGC && ClUseGlobalsGC),
629  // Not a typo: ClWithComdat is almost completely pointless without
630  // ClUseGlobalsGC (because then it only works on modules without
631  // globals, which are rare); it is a prerequisite for ClUseGlobalsGC;
632  // and both suffer from gold PR19002 for which UseGlobalsGC constructor
633  // argument is designed as workaround. Therefore, disable both
634  // ClWithComdat and ClUseGlobalsGC unless the frontend says it's ok to
635  // do globals-gc.
636  UseCtorComdat(UseGlobalsGC && ClWithComdat) {}
637  bool runOnModule(Module &M) override;
638  static char ID; // Pass identification, replacement for typeid
639  StringRef getPassName() const override { return "AddressSanitizerModule"; }
640 
641 private:
642  void initializeCallbacks(Module &M);
643 
644  bool InstrumentGlobals(IRBuilder<> &IRB, Module &M, bool *CtorComdat);
645  void InstrumentGlobalsCOFF(IRBuilder<> &IRB, Module &M,
646  ArrayRef<GlobalVariable *> ExtendedGlobals,
647  ArrayRef<Constant *> MetadataInitializers);
648  void InstrumentGlobalsELF(IRBuilder<> &IRB, Module &M,
649  ArrayRef<GlobalVariable *> ExtendedGlobals,
650  ArrayRef<Constant *> MetadataInitializers,
651  const std::string &UniqueModuleId);
652  void InstrumentGlobalsMachO(IRBuilder<> &IRB, Module &M,
653  ArrayRef<GlobalVariable *> ExtendedGlobals,
654  ArrayRef<Constant *> MetadataInitializers);
655  void
656  InstrumentGlobalsWithMetadataArray(IRBuilder<> &IRB, Module &M,
657  ArrayRef<GlobalVariable *> ExtendedGlobals,
658  ArrayRef<Constant *> MetadataInitializers);
659 
660  GlobalVariable *CreateMetadataGlobal(Module &M, Constant *Initializer,
661  StringRef OriginalName);
662  void SetComdatForGlobalMetadata(GlobalVariable *G, GlobalVariable *Metadata,
663  StringRef InternalSuffix);
664  IRBuilder<> CreateAsanModuleDtor(Module &M);
665 
666  bool ShouldInstrumentGlobal(GlobalVariable *G);
667  bool ShouldUseMachOGlobalsSection() const;
668  StringRef getGlobalMetadataSection() const;
669  void poisonOneInitializer(Function &GlobalInit, GlobalValue *ModuleName);
670  void createInitializerPoisonCalls(Module &M, GlobalValue *ModuleName);
671  size_t MinRedzoneSizeForGlobal() const {
672  return RedzoneSizeForScale(Mapping.Scale);
673  }
674 
675  GlobalsMetadata GlobalsMD;
676  bool CompileKernel;
677  bool Recover;
678  bool UseGlobalsGC;
679  bool UseCtorComdat;
680  Type *IntptrTy;
681  LLVMContext *C;
682  Triple TargetTriple;
683  ShadowMapping Mapping;
684  Function *AsanPoisonGlobals;
685  Function *AsanUnpoisonGlobals;
686  Function *AsanRegisterGlobals;
687  Function *AsanUnregisterGlobals;
688  Function *AsanRegisterImageGlobals;
689  Function *AsanUnregisterImageGlobals;
690  Function *AsanRegisterElfGlobals;
691  Function *AsanUnregisterElfGlobals;
692 
693  Function *AsanCtorFunction = nullptr;
694  Function *AsanDtorFunction = nullptr;
695 };
696 
697 // Stack poisoning does not play well with exception handling.
698 // When an exception is thrown, we essentially bypass the code
699 // that unpoisones the stack. This is why the run-time library has
700 // to intercept __cxa_throw (as well as longjmp, etc) and unpoison the entire
701 // stack in the interceptor. This however does not work inside the
702 // actual function which catches the exception. Most likely because the
703 // compiler hoists the load of the shadow value somewhere too high.
704 // This causes asan to report a non-existing bug on 453.povray.
705 // It sounds like an LLVM bug.
706 struct FunctionStackPoisoner : public InstVisitor<FunctionStackPoisoner> {
707  Function &F;
708  AddressSanitizer &ASan;
709  DIBuilder DIB;
710  LLVMContext *C;
711  Type *IntptrTy;
712  Type *IntptrPtrTy;
713  ShadowMapping Mapping;
714 
716  SmallVector<AllocaInst *, 16> StaticAllocasToMoveUp;
718  unsigned StackAlignment;
719 
720  Function *AsanStackMallocFunc[kMaxAsanStackMallocSizeClass + 1],
721  *AsanStackFreeFunc[kMaxAsanStackMallocSizeClass + 1];
722  Function *AsanSetShadowFunc[0x100] = {};
723  Function *AsanPoisonStackMemoryFunc, *AsanUnpoisonStackMemoryFunc;
724  Function *AsanAllocaPoisonFunc, *AsanAllocasUnpoisonFunc;
725 
726  // Stores a place and arguments of poisoning/unpoisoning call for alloca.
727  struct AllocaPoisonCall {
728  IntrinsicInst *InsBefore;
729  AllocaInst *AI;
730  uint64_t Size;
731  bool DoPoison;
732  };
733  SmallVector<AllocaPoisonCall, 8> DynamicAllocaPoisonCallVec;
734  SmallVector<AllocaPoisonCall, 8> StaticAllocaPoisonCallVec;
735 
736  SmallVector<AllocaInst *, 1> DynamicAllocaVec;
737  SmallVector<IntrinsicInst *, 1> StackRestoreVec;
738  AllocaInst *DynamicAllocaLayout = nullptr;
739  IntrinsicInst *LocalEscapeCall = nullptr;
740 
741  // Maps Value to an AllocaInst from which the Value is originated.
742  typedef DenseMap<Value *, AllocaInst *> AllocaForValueMapTy;
743  AllocaForValueMapTy AllocaForValue;
744 
745  bool HasNonEmptyInlineAsm = false;
746  bool HasReturnsTwiceCall = false;
747  std::unique_ptr<CallInst> EmptyInlineAsm;
748 
749  FunctionStackPoisoner(Function &F, AddressSanitizer &ASan)
750  : F(F),
751  ASan(ASan),
752  DIB(*F.getParent(), /*AllowUnresolved*/ false),
753  C(ASan.C),
754  IntptrTy(ASan.IntptrTy),
755  IntptrPtrTy(PointerType::get(IntptrTy, 0)),
756  Mapping(ASan.Mapping),
757  StackAlignment(1 << Mapping.Scale),
758  EmptyInlineAsm(CallInst::Create(ASan.EmptyAsm)) {}
759 
760  bool runOnFunction() {
761  if (!ClStack) return false;
762 
763  if (ClRedzoneByvalArgs)
764  copyArgsPassedByValToAllocas();
765 
766  // Collect alloca, ret, lifetime instructions etc.
767  for (BasicBlock *BB : depth_first(&F.getEntryBlock())) visit(*BB);
768 
769  if (AllocaVec.empty() && DynamicAllocaVec.empty()) return false;
770 
771  initializeCallbacks(*F.getParent());
772 
773  processDynamicAllocas();
774  processStaticAllocas();
775 
776  if (ClDebugStack) {
777  DEBUG(dbgs() << F);
778  }
779  return true;
780  }
781 
782  // Arguments marked with the "byval" attribute are implicitly copied without
783  // using an alloca instruction. To produce redzones for those arguments, we
784  // copy them a second time into memory allocated with an alloca instruction.
785  void copyArgsPassedByValToAllocas();
786 
787  // Finds all Alloca instructions and puts
788  // poisoned red zones around all of them.
789  // Then unpoison everything back before the function returns.
790  void processStaticAllocas();
791  void processDynamicAllocas();
792 
793  void createDynamicAllocasInitStorage();
794 
795  // ----------------------- Visitors.
796  /// \brief Collect all Ret instructions.
797  void visitReturnInst(ReturnInst &RI) { RetVec.push_back(&RI); }
798 
799  /// \brief Collect all Resume instructions.
800  void visitResumeInst(ResumeInst &RI) { RetVec.push_back(&RI); }
801 
802  /// \brief Collect all CatchReturnInst instructions.
803  void visitCleanupReturnInst(CleanupReturnInst &CRI) { RetVec.push_back(&CRI); }
804 
805  void unpoisonDynamicAllocasBeforeInst(Instruction *InstBefore,
806  Value *SavedStack) {
807  IRBuilder<> IRB(InstBefore);
808  Value *DynamicAreaPtr = IRB.CreatePtrToInt(SavedStack, IntptrTy);
809  // When we insert _asan_allocas_unpoison before @llvm.stackrestore, we
810  // need to adjust extracted SP to compute the address of the most recent
811  // alloca. We have a special @llvm.get.dynamic.area.offset intrinsic for
812  // this purpose.
813  if (!isa<ReturnInst>(InstBefore)) {
814  Function *DynamicAreaOffsetFunc = Intrinsic::getDeclaration(
815  InstBefore->getModule(), Intrinsic::get_dynamic_area_offset,
816  {IntptrTy});
817 
818  Value *DynamicAreaOffset = IRB.CreateCall(DynamicAreaOffsetFunc, {});
819 
820  DynamicAreaPtr = IRB.CreateAdd(IRB.CreatePtrToInt(SavedStack, IntptrTy),
821  DynamicAreaOffset);
822  }
823 
824  IRB.CreateCall(AsanAllocasUnpoisonFunc,
825  {IRB.CreateLoad(DynamicAllocaLayout), DynamicAreaPtr});
826  }
827 
828  // Unpoison dynamic allocas redzones.
829  void unpoisonDynamicAllocas() {
830  for (auto &Ret : RetVec)
831  unpoisonDynamicAllocasBeforeInst(Ret, DynamicAllocaLayout);
832 
833  for (auto &StackRestoreInst : StackRestoreVec)
834  unpoisonDynamicAllocasBeforeInst(StackRestoreInst,
835  StackRestoreInst->getOperand(0));
836  }
837 
838  // Deploy and poison redzones around dynamic alloca call. To do this, we
839  // should replace this call with another one with changed parameters and
840  // replace all its uses with new address, so
841  // addr = alloca type, old_size, align
842  // is replaced by
843  // new_size = (old_size + additional_size) * sizeof(type)
844  // tmp = alloca i8, new_size, max(align, 32)
845  // addr = tmp + 32 (first 32 bytes are for the left redzone).
846  // Additional_size is added to make new memory allocation contain not only
847  // requested memory, but also left, partial and right redzones.
848  void handleDynamicAllocaCall(AllocaInst *AI);
849 
850  /// \brief Collect Alloca instructions we want (and can) handle.
851  void visitAllocaInst(AllocaInst &AI) {
852  if (!ASan.isInterestingAlloca(AI)) {
853  if (AI.isStaticAlloca()) {
854  // Skip over allocas that are present *before* the first instrumented
855  // alloca, we don't want to move those around.
856  if (AllocaVec.empty())
857  return;
858 
859  StaticAllocasToMoveUp.push_back(&AI);
860  }
861  return;
862  }
863 
864  StackAlignment = std::max(StackAlignment, AI.getAlignment());
865  if (!AI.isStaticAlloca())
866  DynamicAllocaVec.push_back(&AI);
867  else
868  AllocaVec.push_back(&AI);
869  }
870 
871  /// \brief Collect lifetime intrinsic calls to check for use-after-scope
872  /// errors.
873  void visitIntrinsicInst(IntrinsicInst &II) {
874  Intrinsic::ID ID = II.getIntrinsicID();
875  if (ID == Intrinsic::stackrestore) StackRestoreVec.push_back(&II);
876  if (ID == Intrinsic::localescape) LocalEscapeCall = &II;
877  if (!ASan.UseAfterScope)
878  return;
879  if (ID != Intrinsic::lifetime_start && ID != Intrinsic::lifetime_end)
880  return;
881  // Found lifetime intrinsic, add ASan instrumentation if necessary.
883  // If size argument is undefined, don't do anything.
884  if (Size->isMinusOne()) return;
885  // Check that size doesn't saturate uint64_t and can
886  // be stored in IntptrTy.
887  const uint64_t SizeValue = Size->getValue().getLimitedValue();
888  if (SizeValue == ~0ULL ||
889  !ConstantInt::isValueValidForType(IntptrTy, SizeValue))
890  return;
891  // Find alloca instruction that corresponds to llvm.lifetime argument.
892  AllocaInst *AI = findAllocaForValue(II.getArgOperand(1));
893  if (!AI || !ASan.isInterestingAlloca(*AI))
894  return;
895  bool DoPoison = (ID == Intrinsic::lifetime_end);
896  AllocaPoisonCall APC = {&II, AI, SizeValue, DoPoison};
897  if (AI->isStaticAlloca())
898  StaticAllocaPoisonCallVec.push_back(APC);
900  DynamicAllocaPoisonCallVec.push_back(APC);
901  }
902 
903  void visitCallSite(CallSite CS) {
904  Instruction *I = CS.getInstruction();
905  if (CallInst *CI = dyn_cast<CallInst>(I)) {
906  HasNonEmptyInlineAsm |=
907  CI->isInlineAsm() && !CI->isIdenticalTo(EmptyInlineAsm.get());
908  HasReturnsTwiceCall |= CI->canReturnTwice();
909  }
910  }
911 
912  // ---------------------- Helpers.
913  void initializeCallbacks(Module &M);
914 
915  bool doesDominateAllExits(const Instruction *I) const {
916  for (auto Ret : RetVec) {
917  if (!ASan.getDominatorTree().dominates(I, Ret)) return false;
918  }
919  return true;
920  }
921 
922  /// Finds alloca where the value comes from.
923  AllocaInst *findAllocaForValue(Value *V);
924 
925  // Copies bytes from ShadowBytes into shadow memory for indexes where
926  // ShadowMask is not zero. If ShadowMask[i] is zero, we assume that
927  // ShadowBytes[i] is constantly zero and doesn't need to be overwritten.
928  void copyToShadow(ArrayRef<uint8_t> ShadowMask, ArrayRef<uint8_t> ShadowBytes,
929  IRBuilder<> &IRB, Value *ShadowBase);
930  void copyToShadow(ArrayRef<uint8_t> ShadowMask, ArrayRef<uint8_t> ShadowBytes,
931  size_t Begin, size_t End, IRBuilder<> &IRB,
932  Value *ShadowBase);
933  void copyToShadowInline(ArrayRef<uint8_t> ShadowMask,
934  ArrayRef<uint8_t> ShadowBytes, size_t Begin,
935  size_t End, IRBuilder<> &IRB, Value *ShadowBase);
936 
937  void poisonAlloca(Value *V, uint64_t Size, IRBuilder<> &IRB, bool DoPoison);
938 
939  Value *createAllocaForLayout(IRBuilder<> &IRB, const ASanStackFrameLayout &L,
940  bool Dynamic);
941  PHINode *createPHI(IRBuilder<> &IRB, Value *Cond, Value *ValueIfTrue,
942  Instruction *ThenTerm, Value *ValueIfFalse);
943 };
944 
945 } // anonymous namespace
946 
947 char AddressSanitizer::ID = 0;
949  AddressSanitizer, "asan",
950  "AddressSanitizer: detects use-after-free and out-of-bounds bugs.", false,
951  false)
955  AddressSanitizer, "asan",
956  "AddressSanitizer: detects use-after-free and out-of-bounds bugs.", false,
957  false)
959  bool Recover,
960  bool UseAfterScope) {
961  assert(!CompileKernel || Recover);
962  return new AddressSanitizer(CompileKernel, Recover, UseAfterScope);
963 }
964 
967  AddressSanitizerModule, "asan-module",
968  "AddressSanitizer: detects use-after-free and out-of-bounds bugs."
969  "ModulePass",
970  false, false)
972  bool Recover,
973  bool UseGlobalsGC) {
974  assert(!CompileKernel || Recover);
975  return new AddressSanitizerModule(CompileKernel, Recover, UseGlobalsGC);
976 }
977 
978 static size_t TypeSizeToSizeIndex(uint32_t TypeSize) {
979  size_t Res = countTrailingZeros(TypeSize / 8);
981  return Res;
982 }
983 
984 // \brief Create a constant for Str so that we can pass it to the run-time lib.
986  bool AllowMerging) {
987  Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
988  // We use private linkage for module-local strings. If they can be merged
989  // with another one, we set the unnamed_addr attribute.
990  GlobalVariable *GV =
991  new GlobalVariable(M, StrConst->getType(), true,
993  if (AllowMerging) GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
994  GV->setAlignment(1); // Strings may not be merged w/o setting align 1.
995  return GV;
996 }
997 
998 /// \brief Create a global describing a source location.
1000  LocationMetadata MD) {
1001  Constant *LocData[] = {
1002  createPrivateGlobalForString(M, MD.Filename, true),
1003  ConstantInt::get(Type::getInt32Ty(M.getContext()), MD.LineNo),
1004  ConstantInt::get(Type::getInt32Ty(M.getContext()), MD.ColumnNo),
1005  };
1006  auto LocStruct = ConstantStruct::getAnon(LocData);
1007  auto GV = new GlobalVariable(M, LocStruct->getType(), true,
1008  GlobalValue::PrivateLinkage, LocStruct,
1009  kAsanGenPrefix);
1011  return GV;
1012 }
1013 
1014 /// \brief Check if \p G has been created by a trusted compiler pass.
1016  // Do not instrument asan globals.
1017  if (G->getName().startswith(kAsanGenPrefix) ||
1018  G->getName().startswith(kSanCovGenPrefix) ||
1019  G->getName().startswith(kODRGenPrefix))
1020  return true;
1021 
1022  // Do not instrument gcov counter arrays.
1023  if (G->getName() == "__llvm_gcov_ctr")
1024  return true;
1025 
1026  return false;
1027 }
1028 
1029 Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
1030  // Shadow >> scale
1031  Shadow = IRB.CreateLShr(Shadow, Mapping.Scale);
1032  if (Mapping.Offset == 0) return Shadow;
1033  // (Shadow >> scale) | offset
1034  Value *ShadowBase;
1035  if (LocalDynamicShadow)
1036  ShadowBase = LocalDynamicShadow;
1037  else
1038  ShadowBase = ConstantInt::get(IntptrTy, Mapping.Offset);
1039  if (Mapping.OrShadowOffset)
1040  return IRB.CreateOr(Shadow, ShadowBase);
1041  else
1042  return IRB.CreateAdd(Shadow, ShadowBase);
1043 }
1044 
1045 // Instrument memset/memmove/memcpy
1046 void AddressSanitizer::instrumentMemIntrinsic(MemIntrinsic *MI) {
1047  IRBuilder<> IRB(MI);
1048  if (isa<MemTransferInst>(MI)) {
1049  IRB.CreateCall(
1050  isa<MemMoveInst>(MI) ? AsanMemmove : AsanMemcpy,
1051  {IRB.CreatePointerCast(MI->getOperand(0), IRB.getInt8PtrTy()),
1052  IRB.CreatePointerCast(MI->getOperand(1), IRB.getInt8PtrTy()),
1053  IRB.CreateIntCast(MI->getOperand(2), IntptrTy, false)});
1054  } else if (isa<MemSetInst>(MI)) {
1055  IRB.CreateCall(
1056  AsanMemset,
1057  {IRB.CreatePointerCast(MI->getOperand(0), IRB.getInt8PtrTy()),
1058  IRB.CreateIntCast(MI->getOperand(1), IRB.getInt32Ty(), false),
1059  IRB.CreateIntCast(MI->getOperand(2), IntptrTy, false)});
1060  }
1061  MI->eraseFromParent();
1062 }
1063 
1064 /// Check if we want (and can) handle this alloca.
1065 bool AddressSanitizer::isInterestingAlloca(const AllocaInst &AI) {
1066  auto PreviouslySeenAllocaInfo = ProcessedAllocas.find(&AI);
1067 
1068  if (PreviouslySeenAllocaInfo != ProcessedAllocas.end())
1069  return PreviouslySeenAllocaInfo->getSecond();
1070 
1071  bool IsInteresting =
1072  (AI.getAllocatedType()->isSized() &&
1073  // alloca() may be called with 0 size, ignore it.
1074  ((!AI.isStaticAlloca()) || getAllocaSizeInBytes(AI) > 0) &&
1075  // We are only interested in allocas not promotable to registers.
1076  // Promotable allocas are common under -O0.
1078  // inalloca allocas are not treated as static, and we don't want
1079  // dynamic alloca instrumentation for them as well.
1080  !AI.isUsedWithInAlloca() &&
1081  // swifterror allocas are register promoted by ISel
1082  !AI.isSwiftError());
1083 
1084  ProcessedAllocas[&AI] = IsInteresting;
1085  return IsInteresting;
1086 }
1087 
1088 Value *AddressSanitizer::isInterestingMemoryAccess(Instruction *I,
1089  bool *IsWrite,
1090  uint64_t *TypeSize,
1091  unsigned *Alignment,
1092  Value **MaybeMask) {
1093  // Skip memory accesses inserted by another instrumentation.
1094  if (I->getMetadata("nosanitize")) return nullptr;
1095 
1096  // Do not instrument the load fetching the dynamic shadow address.
1097  if (LocalDynamicShadow == I)
1098  return nullptr;
1099 
1100  Value *PtrOperand = nullptr;
1101  const DataLayout &DL = I->getModule()->getDataLayout();
1102  if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
1103  if (!ClInstrumentReads) return nullptr;
1104  *IsWrite = false;
1105  *TypeSize = DL.getTypeStoreSizeInBits(LI->getType());
1106  *Alignment = LI->getAlignment();
1107  PtrOperand = LI->getPointerOperand();
1108  } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
1109  if (!ClInstrumentWrites) return nullptr;
1110  *IsWrite = true;
1111  *TypeSize = DL.getTypeStoreSizeInBits(SI->getValueOperand()->getType());
1112  *Alignment = SI->getAlignment();
1113  PtrOperand = SI->getPointerOperand();
1114  } else if (AtomicRMWInst *RMW = dyn_cast<AtomicRMWInst>(I)) {
1115  if (!ClInstrumentAtomics) return nullptr;
1116  *IsWrite = true;
1117  *TypeSize = DL.getTypeStoreSizeInBits(RMW->getValOperand()->getType());
1118  *Alignment = 0;
1119  PtrOperand = RMW->getPointerOperand();
1120  } else if (AtomicCmpXchgInst *XCHG = dyn_cast<AtomicCmpXchgInst>(I)) {
1121  if (!ClInstrumentAtomics) return nullptr;
1122  *IsWrite = true;
1123  *TypeSize = DL.getTypeStoreSizeInBits(XCHG->getCompareOperand()->getType());
1124  *Alignment = 0;
1125  PtrOperand = XCHG->getPointerOperand();
1126  } else if (auto CI = dyn_cast<CallInst>(I)) {
1127  auto *F = dyn_cast<Function>(CI->getCalledValue());
1128  if (F && (F->getName().startswith("llvm.masked.load.") ||
1129  F->getName().startswith("llvm.masked.store."))) {
1130  unsigned OpOffset = 0;
1131  if (F->getName().startswith("llvm.masked.store.")) {
1132  if (!ClInstrumentWrites)
1133  return nullptr;
1134  // Masked store has an initial operand for the value.
1135  OpOffset = 1;
1136  *IsWrite = true;
1137  } else {
1138  if (!ClInstrumentReads)
1139  return nullptr;
1140  *IsWrite = false;
1141  }
1142 
1143  auto BasePtr = CI->getOperand(0 + OpOffset);
1144  auto Ty = cast<PointerType>(BasePtr->getType())->getElementType();
1145  *TypeSize = DL.getTypeStoreSizeInBits(Ty);
1146  if (auto AlignmentConstant =
1147  dyn_cast<ConstantInt>(CI->getOperand(1 + OpOffset)))
1148  *Alignment = (unsigned)AlignmentConstant->getZExtValue();
1149  else
1150  *Alignment = 1; // No alignment guarantees. We probably got Undef
1151  if (MaybeMask)
1152  *MaybeMask = CI->getOperand(2 + OpOffset);
1153  PtrOperand = BasePtr;
1154  }
1155  }
1156 
1157  if (PtrOperand) {
1158  // Do not instrument acesses from different address spaces; we cannot deal
1159  // with them.
1160  Type *PtrTy = cast<PointerType>(PtrOperand->getType()->getScalarType());
1161  if (PtrTy->getPointerAddressSpace() != 0)
1162  return nullptr;
1163 
1164  // Ignore swifterror addresses.
1165  // swifterror memory addresses are mem2reg promoted by instruction
1166  // selection. As such they cannot have regular uses like an instrumentation
1167  // function and it makes no sense to track them as memory.
1168  if (PtrOperand->isSwiftError())
1169  return nullptr;
1170  }
1171 
1172  // Treat memory accesses to promotable allocas as non-interesting since they
1173  // will not cause memory violations. This greatly speeds up the instrumented
1174  // executable at -O0.
1176  if (auto AI = dyn_cast_or_null<AllocaInst>(PtrOperand))
1177  return isInterestingAlloca(*AI) ? AI : nullptr;
1178 
1179  return PtrOperand;
1180 }
1181 
1182 static bool isPointerOperand(Value *V) {
1183  return V->getType()->isPointerTy() || isa<PtrToIntInst>(V);
1184 }
1185 
1186 // This is a rough heuristic; it may cause both false positives and
1187 // false negatives. The proper implementation requires cooperation with
1188 // the frontend.
1190  if (ICmpInst *Cmp = dyn_cast<ICmpInst>(I)) {
1191  if (!Cmp->isRelational()) return false;
1192  } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
1193  if (BO->getOpcode() != Instruction::Sub) return false;
1194  } else {
1195  return false;
1196  }
1197  return isPointerOperand(I->getOperand(0)) &&
1199 }
1200 
1201 bool AddressSanitizer::GlobalIsLinkerInitialized(GlobalVariable *G) {
1202  // If a global variable does not have dynamic initialization we don't
1203  // have to instrument it. However, if a global does not have initializer
1204  // at all, we assume it has dynamic initializer (in other TU).
1205  return G->hasInitializer() && !GlobalsMD.get(G).IsDynInit;
1206 }
1207 
1208 void AddressSanitizer::instrumentPointerComparisonOrSubtraction(
1209  Instruction *I) {
1210  IRBuilder<> IRB(I);
1211  Function *F = isa<ICmpInst>(I) ? AsanPtrCmpFunction : AsanPtrSubFunction;
1212  Value *Param[2] = {I->getOperand(0), I->getOperand(1)};
1213  for (Value *&i : Param) {
1214  if (i->getType()->isPointerTy())
1215  i = IRB.CreatePointerCast(i, IntptrTy);
1216  }
1217  IRB.CreateCall(F, Param);
1218 }
1219 
1220 static void doInstrumentAddress(AddressSanitizer *Pass, Instruction *I,
1221  Instruction *InsertBefore, Value *Addr,
1222  unsigned Alignment, unsigned Granularity,
1223  uint32_t TypeSize, bool IsWrite,
1224  Value *SizeArgument, bool UseCalls,
1225  uint32_t Exp) {
1226  // Instrument a 1-, 2-, 4-, 8-, or 16- byte access with one check
1227  // if the data is properly aligned.
1228  if ((TypeSize == 8 || TypeSize == 16 || TypeSize == 32 || TypeSize == 64 ||
1229  TypeSize == 128) &&
1230  (Alignment >= Granularity || Alignment == 0 || Alignment >= TypeSize / 8))
1231  return Pass->instrumentAddress(I, InsertBefore, Addr, TypeSize, IsWrite,
1232  nullptr, UseCalls, Exp);
1233  Pass->instrumentUnusualSizeOrAlignment(I, InsertBefore, Addr, TypeSize,
1234  IsWrite, nullptr, UseCalls, Exp);
1235 }
1236 
1237 static void instrumentMaskedLoadOrStore(AddressSanitizer *Pass,
1238  const DataLayout &DL, Type *IntptrTy,
1239  Value *Mask, Instruction *I,
1240  Value *Addr, unsigned Alignment,
1241  unsigned Granularity, uint32_t TypeSize,
1242  bool IsWrite, Value *SizeArgument,
1243  bool UseCalls, uint32_t Exp) {
1244  auto *VTy = cast<PointerType>(Addr->getType())->getElementType();
1245  uint64_t ElemTypeSize = DL.getTypeStoreSizeInBits(VTy->getScalarType());
1246  unsigned Num = VTy->getVectorNumElements();
1247  auto Zero = ConstantInt::get(IntptrTy, 0);
1248  for (unsigned Idx = 0; Idx < Num; ++Idx) {
1249  Value *InstrumentedAddress = nullptr;
1250  Instruction *InsertBefore = I;
1251  if (auto *Vector = dyn_cast<ConstantVector>(Mask)) {
1252  // dyn_cast as we might get UndefValue
1253  if (auto *Masked = dyn_cast<ConstantInt>(Vector->getOperand(Idx))) {
1254  if (Masked->isZero())
1255  // Mask is constant false, so no instrumentation needed.
1256  continue;
1257  // If we have a true or undef value, fall through to doInstrumentAddress
1258  // with InsertBefore == I
1259  }
1260  } else {
1261  IRBuilder<> IRB(I);
1262  Value *MaskElem = IRB.CreateExtractElement(Mask, Idx);
1263  TerminatorInst *ThenTerm = SplitBlockAndInsertIfThen(MaskElem, I, false);
1264  InsertBefore = ThenTerm;
1265  }
1266 
1267  IRBuilder<> IRB(InsertBefore);
1268  InstrumentedAddress =
1269  IRB.CreateGEP(Addr, {Zero, ConstantInt::get(IntptrTy, Idx)});
1270  doInstrumentAddress(Pass, I, InsertBefore, InstrumentedAddress, Alignment,
1271  Granularity, ElemTypeSize, IsWrite, SizeArgument,
1272  UseCalls, Exp);
1273  }
1274 }
1275 
1276 void AddressSanitizer::instrumentMop(ObjectSizeOffsetVisitor &ObjSizeVis,
1277  Instruction *I, bool UseCalls,
1278  const DataLayout &DL) {
1279  bool IsWrite = false;
1280  unsigned Alignment = 0;
1281  uint64_t TypeSize = 0;
1282  Value *MaybeMask = nullptr;
1283  Value *Addr =
1284  isInterestingMemoryAccess(I, &IsWrite, &TypeSize, &Alignment, &MaybeMask);
1285  assert(Addr);
1286 
1287  // Optimization experiments.
1288  // The experiments can be used to evaluate potential optimizations that remove
1289  // instrumentation (assess false negatives). Instead of completely removing
1290  // some instrumentation, you set Exp to a non-zero value (mask of optimization
1291  // experiments that want to remove instrumentation of this instruction).
1292  // If Exp is non-zero, this pass will emit special calls into runtime
1293  // (e.g. __asan_report_exp_load1 instead of __asan_report_load1). These calls
1294  // make runtime terminate the program in a special way (with a different
1295  // exit status). Then you run the new compiler on a buggy corpus, collect
1296  // the special terminations (ideally, you don't see them at all -- no false
1297  // negatives) and make the decision on the optimization.
1299 
1300  if (ClOpt && ClOptGlobals) {
1301  // If initialization order checking is disabled, a simple access to a
1302  // dynamically initialized global is always valid.
1304  if (G && (!ClInitializers || GlobalIsLinkerInitialized(G)) &&
1305  isSafeAccess(ObjSizeVis, Addr, TypeSize)) {
1306  NumOptimizedAccessesToGlobalVar++;
1307  return;
1308  }
1309  }
1310 
1311  if (ClOpt && ClOptStack) {
1312  // A direct inbounds access to a stack variable is always valid.
1313  if (isa<AllocaInst>(GetUnderlyingObject(Addr, DL)) &&
1314  isSafeAccess(ObjSizeVis, Addr, TypeSize)) {
1315  NumOptimizedAccessesToStackVar++;
1316  return;
1317  }
1318  }
1319 
1320  if (IsWrite)
1321  NumInstrumentedWrites++;
1322  else
1323  NumInstrumentedReads++;
1324 
1325  unsigned Granularity = 1 << Mapping.Scale;
1326  if (MaybeMask) {
1327  instrumentMaskedLoadOrStore(this, DL, IntptrTy, MaybeMask, I, Addr,
1328  Alignment, Granularity, TypeSize, IsWrite,
1329  nullptr, UseCalls, Exp);
1330  } else {
1331  doInstrumentAddress(this, I, I, Addr, Alignment, Granularity, TypeSize,
1332  IsWrite, nullptr, UseCalls, Exp);
1333  }
1334 }
1335 
1336 Instruction *AddressSanitizer::generateCrashCode(Instruction *InsertBefore,
1337  Value *Addr, bool IsWrite,
1338  size_t AccessSizeIndex,
1339  Value *SizeArgument,
1340  uint32_t Exp) {
1341  IRBuilder<> IRB(InsertBefore);
1342  Value *ExpVal = Exp == 0 ? nullptr : ConstantInt::get(IRB.getInt32Ty(), Exp);
1343  CallInst *Call = nullptr;
1344  if (SizeArgument) {
1345  if (Exp == 0)
1346  Call = IRB.CreateCall(AsanErrorCallbackSized[IsWrite][0],
1347  {Addr, SizeArgument});
1348  else
1349  Call = IRB.CreateCall(AsanErrorCallbackSized[IsWrite][1],
1350  {Addr, SizeArgument, ExpVal});
1351  } else {
1352  if (Exp == 0)
1353  Call =
1354  IRB.CreateCall(AsanErrorCallback[IsWrite][0][AccessSizeIndex], Addr);
1355  else
1356  Call = IRB.CreateCall(AsanErrorCallback[IsWrite][1][AccessSizeIndex],
1357  {Addr, ExpVal});
1358  }
1359 
1360  // We don't do Call->setDoesNotReturn() because the BB already has
1361  // UnreachableInst at the end.
1362  // This EmptyAsm is required to avoid callback merge.
1363  IRB.CreateCall(EmptyAsm, {});
1364  return Call;
1365 }
1366 
1367 Value *AddressSanitizer::createSlowPathCmp(IRBuilder<> &IRB, Value *AddrLong,
1368  Value *ShadowValue,
1369  uint32_t TypeSize) {
1370  size_t Granularity = static_cast<size_t>(1) << Mapping.Scale;
1371  // Addr & (Granularity - 1)
1372  Value *LastAccessedByte =
1373  IRB.CreateAnd(AddrLong, ConstantInt::get(IntptrTy, Granularity - 1));
1374  // (Addr & (Granularity - 1)) + size - 1
1375  if (TypeSize / 8 > 1)
1376  LastAccessedByte = IRB.CreateAdd(
1377  LastAccessedByte, ConstantInt::get(IntptrTy, TypeSize / 8 - 1));
1378  // (uint8_t) ((Addr & (Granularity-1)) + size - 1)
1379  LastAccessedByte =
1380  IRB.CreateIntCast(LastAccessedByte, ShadowValue->getType(), false);
1381  // ((uint8_t) ((Addr & (Granularity-1)) + size - 1)) >= ShadowValue
1382  return IRB.CreateICmpSGE(LastAccessedByte, ShadowValue);
1383 }
1384 
1385 void AddressSanitizer::instrumentAddress(Instruction *OrigIns,
1386  Instruction *InsertBefore, Value *Addr,
1387  uint32_t TypeSize, bool IsWrite,
1388  Value *SizeArgument, bool UseCalls,
1389  uint32_t Exp) {
1390  IRBuilder<> IRB(InsertBefore);
1391  Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
1392  size_t AccessSizeIndex = TypeSizeToSizeIndex(TypeSize);
1393 
1394  if (UseCalls) {
1395  if (Exp == 0)
1396  IRB.CreateCall(AsanMemoryAccessCallback[IsWrite][0][AccessSizeIndex],
1397  AddrLong);
1398  else
1399  IRB.CreateCall(AsanMemoryAccessCallback[IsWrite][1][AccessSizeIndex],
1400  {AddrLong, ConstantInt::get(IRB.getInt32Ty(), Exp)});
1401  return;
1402  }
1403 
1404  Type *ShadowTy =
1405  IntegerType::get(*C, std::max(8U, TypeSize >> Mapping.Scale));
1406  Type *ShadowPtrTy = PointerType::get(ShadowTy, 0);
1407  Value *ShadowPtr = memToShadow(AddrLong, IRB);
1408  Value *CmpVal = Constant::getNullValue(ShadowTy);
1409  Value *ShadowValue =
1410  IRB.CreateLoad(IRB.CreateIntToPtr(ShadowPtr, ShadowPtrTy));
1411 
1412  Value *Cmp = IRB.CreateICmpNE(ShadowValue, CmpVal);
1413  size_t Granularity = 1ULL << Mapping.Scale;
1414  TerminatorInst *CrashTerm = nullptr;
1415 
1416  if (ClAlwaysSlowPath || (TypeSize < 8 * Granularity)) {
1417  // We use branch weights for the slow path check, to indicate that the slow
1418  // path is rarely taken. This seems to be the case for SPEC benchmarks.
1420  Cmp, InsertBefore, false, MDBuilder(*C).createBranchWeights(1, 100000));
1421  assert(cast<BranchInst>(CheckTerm)->isUnconditional());
1422  BasicBlock *NextBB = CheckTerm->getSuccessor(0);
1423  IRB.SetInsertPoint(CheckTerm);
1424  Value *Cmp2 = createSlowPathCmp(IRB, AddrLong, ShadowValue, TypeSize);
1425  if (Recover) {
1426  CrashTerm = SplitBlockAndInsertIfThen(Cmp2, CheckTerm, false);
1427  } else {
1428  BasicBlock *CrashBlock =
1429  BasicBlock::Create(*C, "", NextBB->getParent(), NextBB);
1430  CrashTerm = new UnreachableInst(*C, CrashBlock);
1431  BranchInst *NewTerm = BranchInst::Create(CrashBlock, NextBB, Cmp2);
1432  ReplaceInstWithInst(CheckTerm, NewTerm);
1433  }
1434  } else {
1435  CrashTerm = SplitBlockAndInsertIfThen(Cmp, InsertBefore, !Recover);
1436  }
1437 
1438  Instruction *Crash = generateCrashCode(CrashTerm, AddrLong, IsWrite,
1439  AccessSizeIndex, SizeArgument, Exp);
1440  Crash->setDebugLoc(OrigIns->getDebugLoc());
1441 }
1442 
1443 // Instrument unusual size or unusual alignment.
1444 // We can not do it with a single check, so we do 1-byte check for the first
1445 // and the last bytes. We call __asan_report_*_n(addr, real_size) to be able
1446 // to report the actual access size.
1447 void AddressSanitizer::instrumentUnusualSizeOrAlignment(
1448  Instruction *I, Instruction *InsertBefore, Value *Addr, uint32_t TypeSize,
1449  bool IsWrite, Value *SizeArgument, bool UseCalls, uint32_t Exp) {
1450  IRBuilder<> IRB(InsertBefore);
1451  Value *Size = ConstantInt::get(IntptrTy, TypeSize / 8);
1452  Value *AddrLong = IRB.CreatePointerCast(Addr, IntptrTy);
1453  if (UseCalls) {
1454  if (Exp == 0)
1455  IRB.CreateCall(AsanMemoryAccessCallbackSized[IsWrite][0],
1456  {AddrLong, Size});
1457  else
1458  IRB.CreateCall(AsanMemoryAccessCallbackSized[IsWrite][1],
1459  {AddrLong, Size, ConstantInt::get(IRB.getInt32Ty(), Exp)});
1460  } else {
1461  Value *LastByte = IRB.CreateIntToPtr(
1462  IRB.CreateAdd(AddrLong, ConstantInt::get(IntptrTy, TypeSize / 8 - 1)),
1463  Addr->getType());
1464  instrumentAddress(I, InsertBefore, Addr, 8, IsWrite, Size, false, Exp);
1465  instrumentAddress(I, InsertBefore, LastByte, 8, IsWrite, Size, false, Exp);
1466  }
1467 }
1468 
1469 void AddressSanitizerModule::poisonOneInitializer(Function &GlobalInit,
1470  GlobalValue *ModuleName) {
1471  // Set up the arguments to our poison/unpoison functions.
1472  IRBuilder<> IRB(&GlobalInit.front(),
1473  GlobalInit.front().getFirstInsertionPt());
1474 
1475  // Add a call to poison all external globals before the given function starts.
1476  Value *ModuleNameAddr = ConstantExpr::getPointerCast(ModuleName, IntptrTy);
1477  IRB.CreateCall(AsanPoisonGlobals, ModuleNameAddr);
1478 
1479  // Add calls to unpoison all globals before each return instruction.
1480  for (auto &BB : GlobalInit.getBasicBlockList())
1481  if (ReturnInst *RI = dyn_cast<ReturnInst>(BB.getTerminator()))
1482  CallInst::Create(AsanUnpoisonGlobals, "", RI);
1483 }
1484 
1485 void AddressSanitizerModule::createInitializerPoisonCalls(
1486  Module &M, GlobalValue *ModuleName) {
1487  GlobalVariable *GV = M.getGlobalVariable("llvm.global_ctors");
1488  if (!GV)
1489  return;
1490 
1492  if (!CA)
1493  return;
1494 
1495  for (Use &OP : CA->operands()) {
1496  if (isa<ConstantAggregateZero>(OP)) continue;
1497  ConstantStruct *CS = cast<ConstantStruct>(OP);
1498 
1499  // Must have a function or null ptr.
1500  if (Function *F = dyn_cast<Function>(CS->getOperand(1))) {
1501  if (F->getName() == kAsanModuleCtorName) continue;
1502  ConstantInt *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
1503  // Don't instrument CTORs that will run before asan.module_ctor.
1504  if (Priority->getLimitedValue() <= kAsanCtorAndDtorPriority) continue;
1505  poisonOneInitializer(*F, ModuleName);
1506  }
1507  }
1508 }
1509 
1510 bool AddressSanitizerModule::ShouldInstrumentGlobal(GlobalVariable *G) {
1511  Type *Ty = G->getValueType();
1512  DEBUG(dbgs() << "GLOBAL: " << *G << "\n");
1513 
1514  if (GlobalsMD.get(G).IsBlacklisted) return false;
1515  if (!Ty->isSized()) return false;
1516  if (!G->hasInitializer()) return false;
1517  if (GlobalWasGeneratedByCompiler(G)) return false; // Our own globals.
1518  // Touch only those globals that will not be defined in other modules.
1519  // Don't handle ODR linkage types and COMDATs since other modules may be built
1520  // without ASan.
1524  return false;
1525  if (G->hasComdat()) return false;
1526  // Two problems with thread-locals:
1527  // - The address of the main thread's copy can't be computed at link-time.
1528  // - Need to poison all copies, not just the main thread's one.
1529  if (G->isThreadLocal()) return false;
1530  // For now, just ignore this Global if the alignment is large.
1531  if (G->getAlignment() > MinRedzoneSizeForGlobal()) return false;
1532 
1533  if (G->hasSection()) {
1534  StringRef Section = G->getSection();
1535 
1536  // Globals from llvm.metadata aren't emitted, do not instrument them.
1537  if (Section == "llvm.metadata") return false;
1538  // Do not instrument globals from special LLVM sections.
1539  if (Section.find("__llvm") != StringRef::npos || Section.find("__LLVM") != StringRef::npos) return false;
1540 
1541  // Do not instrument function pointers to initialization and termination
1542  // routines: dynamic linker will not properly handle redzones.
1543  if (Section.startswith(".preinit_array") ||
1544  Section.startswith(".init_array") ||
1545  Section.startswith(".fini_array")) {
1546  return false;
1547  }
1548 
1549  // Callbacks put into the CRT initializer/terminator sections
1550  // should not be instrumented.
1551  // See https://code.google.com/p/address-sanitizer/issues/detail?id=305
1552  // and http://msdn.microsoft.com/en-US/en-en/library/bb918180(v=vs.120).aspx
1553  if (Section.startswith(".CRT")) {
1554  DEBUG(dbgs() << "Ignoring a global initializer callback: " << *G << "\n");
1555  return false;
1556  }
1557 
1558  if (TargetTriple.isOSBinFormatMachO()) {
1559  StringRef ParsedSegment, ParsedSection;
1560  unsigned TAA = 0, StubSize = 0;
1561  bool TAAParsed;
1562  std::string ErrorCode = MCSectionMachO::ParseSectionSpecifier(
1563  Section, ParsedSegment, ParsedSection, TAA, TAAParsed, StubSize);
1564  assert(ErrorCode.empty() && "Invalid section specifier.");
1565 
1566  // Ignore the globals from the __OBJC section. The ObjC runtime assumes
1567  // those conform to /usr/lib/objc/runtime.h, so we can't add redzones to
1568  // them.
1569  if (ParsedSegment == "__OBJC" ||
1570  (ParsedSegment == "__DATA" && ParsedSection.startswith("__objc_"))) {
1571  DEBUG(dbgs() << "Ignoring ObjC runtime global: " << *G << "\n");
1572  return false;
1573  }
1574  // See http://code.google.com/p/address-sanitizer/issues/detail?id=32
1575  // Constant CFString instances are compiled in the following way:
1576  // -- the string buffer is emitted into
1577  // __TEXT,__cstring,cstring_literals
1578  // -- the constant NSConstantString structure referencing that buffer
1579  // is placed into __DATA,__cfstring
1580  // Therefore there's no point in placing redzones into __DATA,__cfstring.
1581  // Moreover, it causes the linker to crash on OS X 10.7
1582  if (ParsedSegment == "__DATA" && ParsedSection == "__cfstring") {
1583  DEBUG(dbgs() << "Ignoring CFString: " << *G << "\n");
1584  return false;
1585  }
1586  // The linker merges the contents of cstring_literals and removes the
1587  // trailing zeroes.
1588  if (ParsedSegment == "__TEXT" && (TAA & MachO::S_CSTRING_LITERALS)) {
1589  DEBUG(dbgs() << "Ignoring a cstring literal: " << *G << "\n");
1590  return false;
1591  }
1592  }
1593  }
1594 
1595  return true;
1596 }
1597 
1598 // On Mach-O platforms, we emit global metadata in a separate section of the
1599 // binary in order to allow the linker to properly dead strip. This is only
1600 // supported on recent versions of ld64.
1601 bool AddressSanitizerModule::ShouldUseMachOGlobalsSection() const {
1602  if (!TargetTriple.isOSBinFormatMachO())
1603  return false;
1604 
1605  if (TargetTriple.isMacOSX() && !TargetTriple.isMacOSXVersionLT(10, 11))
1606  return true;
1607  if (TargetTriple.isiOS() /* or tvOS */ && !TargetTriple.isOSVersionLT(9))
1608  return true;
1609  if (TargetTriple.isWatchOS() && !TargetTriple.isOSVersionLT(2))
1610  return true;
1611 
1612  return false;
1613 }
1614 
1615 StringRef AddressSanitizerModule::getGlobalMetadataSection() const {
1616  switch (TargetTriple.getObjectFormat()) {
1617  case Triple::COFF: return ".ASAN$GL";
1618  case Triple::ELF: return "asan_globals";
1619  case Triple::MachO: return "__DATA,__asan_globals,regular";
1620  default: break;
1621  }
1622  llvm_unreachable("unsupported object format");
1623 }
1624 
1625 void AddressSanitizerModule::initializeCallbacks(Module &M) {
1626  IRBuilder<> IRB(*C);
1627 
1628  // Declare our poisoning and unpoisoning functions.
1630  kAsanPoisonGlobalsName, IRB.getVoidTy(), IntptrTy));
1631  AsanPoisonGlobals->setLinkage(Function::ExternalLinkage);
1632  AsanUnpoisonGlobals = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
1633  kAsanUnpoisonGlobalsName, IRB.getVoidTy()));
1634  AsanUnpoisonGlobals->setLinkage(Function::ExternalLinkage);
1635 
1636  // Declare functions that register/unregister globals.
1637  AsanRegisterGlobals = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
1638  kAsanRegisterGlobalsName, IRB.getVoidTy(), IntptrTy, IntptrTy));
1639  AsanRegisterGlobals->setLinkage(Function::ExternalLinkage);
1640  AsanUnregisterGlobals = checkSanitizerInterfaceFunction(
1641  M.getOrInsertFunction(kAsanUnregisterGlobalsName, IRB.getVoidTy(),
1642  IntptrTy, IntptrTy));
1643  AsanUnregisterGlobals->setLinkage(Function::ExternalLinkage);
1644 
1645  // Declare the functions that find globals in a shared object and then invoke
1646  // the (un)register function on them.
1647  AsanRegisterImageGlobals =
1649  kAsanRegisterImageGlobalsName, IRB.getVoidTy(), IntptrTy));
1650  AsanRegisterImageGlobals->setLinkage(Function::ExternalLinkage);
1651 
1652  AsanUnregisterImageGlobals =
1654  kAsanUnregisterImageGlobalsName, IRB.getVoidTy(), IntptrTy));
1655  AsanUnregisterImageGlobals->setLinkage(Function::ExternalLinkage);
1656 
1657  AsanRegisterElfGlobals = checkSanitizerInterfaceFunction(
1658  M.getOrInsertFunction(kAsanRegisterElfGlobalsName, IRB.getVoidTy(),
1659  IntptrTy, IntptrTy, IntptrTy));
1660  AsanRegisterElfGlobals->setLinkage(Function::ExternalLinkage);
1661 
1662  AsanUnregisterElfGlobals = checkSanitizerInterfaceFunction(
1663  M.getOrInsertFunction(kAsanUnregisterElfGlobalsName, IRB.getVoidTy(),
1664  IntptrTy, IntptrTy, IntptrTy));
1665  AsanUnregisterElfGlobals->setLinkage(Function::ExternalLinkage);
1666 }
1667 
1668 // Put the metadata and the instrumented global in the same group. This ensures
1669 // that the metadata is discarded if the instrumented global is discarded.
1670 void AddressSanitizerModule::SetComdatForGlobalMetadata(
1671  GlobalVariable *G, GlobalVariable *Metadata, StringRef InternalSuffix) {
1672  Module &M = *G->getParent();
1673  Comdat *C = G->getComdat();
1674  if (!C) {
1675  if (!G->hasName()) {
1676  // If G is unnamed, it must be internal. Give it an artificial name
1677  // so we can put it in a comdat.
1678  assert(G->hasLocalLinkage());
1679  G->setName(Twine(kAsanGenPrefix) + "_anon_global");
1680  }
1681 
1682  if (!InternalSuffix.empty() && G->hasLocalLinkage()) {
1683  std::string Name = G->getName();
1684  Name += InternalSuffix;
1685  C = M.getOrInsertComdat(Name);
1686  } else {
1687  C = M.getOrInsertComdat(G->getName());
1688  }
1689 
1690  // Make this IMAGE_COMDAT_SELECT_NODUPLICATES on COFF.
1691  if (TargetTriple.isOSBinFormatCOFF())
1693  G->setComdat(C);
1694  }
1695 
1696  assert(G->hasComdat());
1697  Metadata->setComdat(G->getComdat());
1698 }
1699 
1700 // Create a separate metadata global and put it in the appropriate ASan
1701 // global registration section.
1703 AddressSanitizerModule::CreateMetadataGlobal(Module &M, Constant *Initializer,
1704  StringRef OriginalName) {
1705  auto Linkage = TargetTriple.isOSBinFormatMachO()
1708  GlobalVariable *Metadata = new GlobalVariable(
1709  M, Initializer->getType(), false, Linkage, Initializer,
1710  Twine("__asan_global_") + GlobalValue::dropLLVMManglingEscape(OriginalName));
1711  Metadata->setSection(getGlobalMetadataSection());
1712  return Metadata;
1713 }
1714 
1715 IRBuilder<> AddressSanitizerModule::CreateAsanModuleDtor(Module &M) {
1716  AsanDtorFunction =
1718  GlobalValue::InternalLinkage, kAsanModuleDtorName, &M);
1719  BasicBlock *AsanDtorBB = BasicBlock::Create(*C, "", AsanDtorFunction);
1720 
1721  return IRBuilder<>(ReturnInst::Create(*C, AsanDtorBB));
1722 }
1723 
1724 void AddressSanitizerModule::InstrumentGlobalsCOFF(
1725  IRBuilder<> &IRB, Module &M, ArrayRef<GlobalVariable *> ExtendedGlobals,
1726  ArrayRef<Constant *> MetadataInitializers) {
1727  assert(ExtendedGlobals.size() == MetadataInitializers.size());
1728  auto &DL = M.getDataLayout();
1729 
1730  for (size_t i = 0; i < ExtendedGlobals.size(); i++) {
1731  Constant *Initializer = MetadataInitializers[i];
1732  GlobalVariable *G = ExtendedGlobals[i];
1733  GlobalVariable *Metadata =
1734  CreateMetadataGlobal(M, Initializer, G->getName());
1735 
1736  // The MSVC linker always inserts padding when linking incrementally. We
1737  // cope with that by aligning each struct to its size, which must be a power
1738  // of two.
1739  unsigned SizeOfGlobalStruct = DL.getTypeAllocSize(Initializer->getType());
1740  assert(isPowerOf2_32(SizeOfGlobalStruct) &&
1741  "global metadata will not be padded appropriately");
1742  Metadata->setAlignment(SizeOfGlobalStruct);
1743 
1744  SetComdatForGlobalMetadata(G, Metadata, "");
1745  }
1746 }
1747 
1748 void AddressSanitizerModule::InstrumentGlobalsELF(
1749  IRBuilder<> &IRB, Module &M, ArrayRef<GlobalVariable *> ExtendedGlobals,
1750  ArrayRef<Constant *> MetadataInitializers,
1751  const std::string &UniqueModuleId) {
1752  assert(ExtendedGlobals.size() == MetadataInitializers.size());
1753 
1754  SmallVector<GlobalValue *, 16> MetadataGlobals(ExtendedGlobals.size());
1755  for (size_t i = 0; i < ExtendedGlobals.size(); i++) {
1756  GlobalVariable *G = ExtendedGlobals[i];
1757  GlobalVariable *Metadata =
1758  CreateMetadataGlobal(M, MetadataInitializers[i], G->getName());
1760  Metadata->setMetadata(LLVMContext::MD_associated, MD);
1761  MetadataGlobals[i] = Metadata;
1762 
1763  SetComdatForGlobalMetadata(G, Metadata, UniqueModuleId);
1764  }
1765 
1766  // Update llvm.compiler.used, adding the new metadata globals. This is
1767  // needed so that during LTO these variables stay alive.
1768  if (!MetadataGlobals.empty())
1769  appendToCompilerUsed(M, MetadataGlobals);
1770 
1771  // RegisteredFlag serves two purposes. First, we can pass it to dladdr()
1772  // to look up the loaded image that contains it. Second, we can store in it
1773  // whether registration has already occurred, to prevent duplicate
1774  // registration.
1775  //
1776  // Common linkage ensures that there is only one global per shared library.
1777  GlobalVariable *RegisteredFlag = new GlobalVariable(
1778  M, IntptrTy, false, GlobalVariable::CommonLinkage,
1779  ConstantInt::get(IntptrTy, 0), kAsanGlobalsRegisteredFlagName);
1781 
1782  // Create start and stop symbols.
1783  GlobalVariable *StartELFMetadata = new GlobalVariable(
1784  M, IntptrTy, false, GlobalVariable::ExternalWeakLinkage, nullptr,
1785  "__start_" + getGlobalMetadataSection());
1787  GlobalVariable *StopELFMetadata = new GlobalVariable(
1788  M, IntptrTy, false, GlobalVariable::ExternalWeakLinkage, nullptr,
1789  "__stop_" + getGlobalMetadataSection());
1791 
1792  // Create a call to register the globals with the runtime.
1793  IRB.CreateCall(AsanRegisterElfGlobals,
1794  {IRB.CreatePointerCast(RegisteredFlag, IntptrTy),
1795  IRB.CreatePointerCast(StartELFMetadata, IntptrTy),
1796  IRB.CreatePointerCast(StopELFMetadata, IntptrTy)});
1797 
1798  // We also need to unregister globals at the end, e.g., when a shared library
1799  // gets closed.
1800  IRBuilder<> IRB_Dtor = CreateAsanModuleDtor(M);
1801  IRB_Dtor.CreateCall(AsanUnregisterElfGlobals,
1802  {IRB.CreatePointerCast(RegisteredFlag, IntptrTy),
1803  IRB.CreatePointerCast(StartELFMetadata, IntptrTy),
1804  IRB.CreatePointerCast(StopELFMetadata, IntptrTy)});
1805 }
1806 
1807 void AddressSanitizerModule::InstrumentGlobalsMachO(
1808  IRBuilder<> &IRB, Module &M, ArrayRef<GlobalVariable *> ExtendedGlobals,
1809  ArrayRef<Constant *> MetadataInitializers) {
1810  assert(ExtendedGlobals.size() == MetadataInitializers.size());
1811 
1812  // On recent Mach-O platforms, use a structure which binds the liveness of
1813  // the global variable to the metadata struct. Keep the list of "Liveness" GV
1814  // created to be added to llvm.compiler.used
1815  StructType *LivenessTy = StructType::get(IntptrTy, IntptrTy);
1816  SmallVector<GlobalValue *, 16> LivenessGlobals(ExtendedGlobals.size());
1817 
1818  for (size_t i = 0; i < ExtendedGlobals.size(); i++) {
1819  Constant *Initializer = MetadataInitializers[i];
1820  GlobalVariable *G = ExtendedGlobals[i];
1821  GlobalVariable *Metadata =
1822  CreateMetadataGlobal(M, Initializer, G->getName());
1823 
1824  // On recent Mach-O platforms, we emit the global metadata in a way that
1825  // allows the linker to properly strip dead globals.
1826  auto LivenessBinder =
1827  ConstantStruct::get(LivenessTy, Initializer->getAggregateElement(0u),
1828  ConstantExpr::getPointerCast(Metadata, IntptrTy));
1829  GlobalVariable *Liveness = new GlobalVariable(
1830  M, LivenessTy, false, GlobalVariable::InternalLinkage, LivenessBinder,
1831  Twine("__asan_binder_") + G->getName());
1832  Liveness->setSection("__DATA,__asan_liveness,regular,live_support");
1833  LivenessGlobals[i] = Liveness;
1834  }
1835 
1836  // Update llvm.compiler.used, adding the new liveness globals. This is
1837  // needed so that during LTO these variables stay alive. The alternative
1838  // would be to have the linker handling the LTO symbols, but libLTO
1839  // current API does not expose access to the section for each symbol.
1840  if (!LivenessGlobals.empty())
1841  appendToCompilerUsed(M, LivenessGlobals);
1842 
1843  // RegisteredFlag serves two purposes. First, we can pass it to dladdr()
1844  // to look up the loaded image that contains it. Second, we can store in it
1845  // whether registration has already occurred, to prevent duplicate
1846  // registration.
1847  //
1848  // common linkage ensures that there is only one global per shared library.
1849  GlobalVariable *RegisteredFlag = new GlobalVariable(
1850  M, IntptrTy, false, GlobalVariable::CommonLinkage,
1851  ConstantInt::get(IntptrTy, 0), kAsanGlobalsRegisteredFlagName);
1853 
1854  IRB.CreateCall(AsanRegisterImageGlobals,
1855  {IRB.CreatePointerCast(RegisteredFlag, IntptrTy)});
1856 
1857  // We also need to unregister globals at the end, e.g., when a shared library
1858  // gets closed.
1859  IRBuilder<> IRB_Dtor = CreateAsanModuleDtor(M);
1860  IRB_Dtor.CreateCall(AsanUnregisterImageGlobals,
1861  {IRB.CreatePointerCast(RegisteredFlag, IntptrTy)});
1862 }
1863 
1864 void AddressSanitizerModule::InstrumentGlobalsWithMetadataArray(
1865  IRBuilder<> &IRB, Module &M, ArrayRef<GlobalVariable *> ExtendedGlobals,
1866  ArrayRef<Constant *> MetadataInitializers) {
1867  assert(ExtendedGlobals.size() == MetadataInitializers.size());
1868  unsigned N = ExtendedGlobals.size();
1869  assert(N > 0);
1870 
1871  // On platforms that don't have a custom metadata section, we emit an array
1872  // of global metadata structures.
1873  ArrayType *ArrayOfGlobalStructTy =
1874  ArrayType::get(MetadataInitializers[0]->getType(), N);
1875  auto AllGlobals = new GlobalVariable(
1876  M, ArrayOfGlobalStructTy, false, GlobalVariable::InternalLinkage,
1877  ConstantArray::get(ArrayOfGlobalStructTy, MetadataInitializers), "");
1878 
1879  IRB.CreateCall(AsanRegisterGlobals,
1880  {IRB.CreatePointerCast(AllGlobals, IntptrTy),
1881  ConstantInt::get(IntptrTy, N)});
1882 
1883  // We also need to unregister globals at the end, e.g., when a shared library
1884  // gets closed.
1885  IRBuilder<> IRB_Dtor = CreateAsanModuleDtor(M);
1886  IRB_Dtor.CreateCall(AsanUnregisterGlobals,
1887  {IRB.CreatePointerCast(AllGlobals, IntptrTy),
1888  ConstantInt::get(IntptrTy, N)});
1889 }
1890 
1891 // This function replaces all global variables with new variables that have
1892 // trailing redzones. It also creates a function that poisons
1893 // redzones and inserts this function into llvm.global_ctors.
1894 // Sets *CtorComdat to true if the global registration code emitted into the
1895 // asan constructor is comdat-compatible.
1896 bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M, bool *CtorComdat) {
1897  *CtorComdat = false;
1898  GlobalsMD.init(M);
1899 
1900  SmallVector<GlobalVariable *, 16> GlobalsToChange;
1901 
1902  for (auto &G : M.globals()) {
1903  if (ShouldInstrumentGlobal(&G)) GlobalsToChange.push_back(&G);
1904  }
1905 
1906  size_t n = GlobalsToChange.size();
1907  if (n == 0) {
1908  *CtorComdat = true;
1909  return false;
1910  }
1911 
1912  auto &DL = M.getDataLayout();
1913 
1914  // A global is described by a structure
1915  // size_t beg;
1916  // size_t size;
1917  // size_t size_with_redzone;
1918  // const char *name;
1919  // const char *module_name;
1920  // size_t has_dynamic_init;
1921  // void *source_location;
1922  // size_t odr_indicator;
1923  // We initialize an array of such structures and pass it to a run-time call.
1924  StructType *GlobalStructTy =
1925  StructType::get(IntptrTy, IntptrTy, IntptrTy, IntptrTy, IntptrTy,
1926  IntptrTy, IntptrTy, IntptrTy);
1927  SmallVector<GlobalVariable *, 16> NewGlobals(n);
1928  SmallVector<Constant *, 16> Initializers(n);
1929 
1930  bool HasDynamicallyInitializedGlobals = false;
1931 
1932  // We shouldn't merge same module names, as this string serves as unique
1933  // module ID in runtime.
1935  M, M.getModuleIdentifier(), /*AllowMerging*/ false);
1936 
1937  for (size_t i = 0; i < n; i++) {
1938  static const uint64_t kMaxGlobalRedzone = 1 << 18;
1939  GlobalVariable *G = GlobalsToChange[i];
1940 
1941  auto MD = GlobalsMD.get(G);
1942  StringRef NameForGlobal = G->getName();
1943  // Create string holding the global name (use global name from metadata
1944  // if it's available, otherwise just write the name of global variable).
1946  M, MD.Name.empty() ? NameForGlobal : MD.Name,
1947  /*AllowMerging*/ true);
1948 
1949  Type *Ty = G->getValueType();
1950  uint64_t SizeInBytes = DL.getTypeAllocSize(Ty);
1951  uint64_t MinRZ = MinRedzoneSizeForGlobal();
1952  // MinRZ <= RZ <= kMaxGlobalRedzone
1953  // and trying to make RZ to be ~ 1/4 of SizeInBytes.
1954  uint64_t RZ = std::max(
1955  MinRZ, std::min(kMaxGlobalRedzone, (SizeInBytes / MinRZ / 4) * MinRZ));
1956  uint64_t RightRedzoneSize = RZ;
1957  // Round up to MinRZ
1958  if (SizeInBytes % MinRZ) RightRedzoneSize += MinRZ - (SizeInBytes % MinRZ);
1959  assert(((RightRedzoneSize + SizeInBytes) % MinRZ) == 0);
1960  Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
1961 
1962  StructType *NewTy = StructType::get(Ty, RightRedZoneTy);
1963  Constant *NewInitializer = ConstantStruct::get(
1964  NewTy, G->getInitializer(), Constant::getNullValue(RightRedZoneTy));
1965 
1966  // Create a new global variable with enough space for a redzone.
1967  GlobalValue::LinkageTypes Linkage = G->getLinkage();
1968  if (G->isConstant() && Linkage == GlobalValue::PrivateLinkage)
1969  Linkage = GlobalValue::InternalLinkage;
1970  GlobalVariable *NewGlobal =
1971  new GlobalVariable(M, NewTy, G->isConstant(), Linkage, NewInitializer,
1972  "", G, G->getThreadLocalMode());
1973  NewGlobal->copyAttributesFrom(G);
1974  NewGlobal->setAlignment(MinRZ);
1975 
1976  // Move null-terminated C strings to "__asan_cstring" section on Darwin.
1977  if (TargetTriple.isOSBinFormatMachO() && !G->hasSection() &&
1978  G->isConstant()) {
1979  auto Seq = dyn_cast<ConstantDataSequential>(G->getInitializer());
1980  if (Seq && Seq->isCString())
1981  NewGlobal->setSection("__TEXT,__asan_cstring,regular");
1982  }
1983 
1984  // Transfer the debug info. The payload starts at offset zero so we can
1985  // copy the debug info over as is.
1987  G->getDebugInfo(GVs);
1988  for (auto *GV : GVs)
1989  NewGlobal->addDebugInfo(GV);
1990 
1991  Value *Indices2[2];
1992  Indices2[0] = IRB.getInt32(0);
1993  Indices2[1] = IRB.getInt32(0);
1994 
1995  G->replaceAllUsesWith(
1996  ConstantExpr::getGetElementPtr(NewTy, NewGlobal, Indices2, true));
1997  NewGlobal->takeName(G);
1998  G->eraseFromParent();
1999  NewGlobals[i] = NewGlobal;
2000 
2001  Constant *SourceLoc;
2002  if (!MD.SourceLoc.empty()) {
2003  auto SourceLocGlobal = createPrivateGlobalForSourceLoc(M, MD.SourceLoc);
2004  SourceLoc = ConstantExpr::getPointerCast(SourceLocGlobal, IntptrTy);
2005  } else {
2006  SourceLoc = ConstantInt::get(IntptrTy, 0);
2007  }
2008 
2009  Constant *ODRIndicator = ConstantExpr::getNullValue(IRB.getInt8PtrTy());
2010  GlobalValue *InstrumentedGlobal = NewGlobal;
2011 
2012  bool CanUsePrivateAliases =
2013  TargetTriple.isOSBinFormatELF() || TargetTriple.isOSBinFormatMachO() ||
2014  TargetTriple.isOSBinFormatWasm();
2015  if (CanUsePrivateAliases && ClUsePrivateAliasForGlobals) {
2016  // Create local alias for NewGlobal to avoid crash on ODR between
2017  // instrumented and non-instrumented libraries.
2019  NameForGlobal + M.getName(), NewGlobal);
2020 
2021  // With local aliases, we need to provide another externally visible
2022  // symbol __odr_asan_XXX to detect ODR violation.
2023  auto *ODRIndicatorSym =
2024  new GlobalVariable(M, IRB.getInt8Ty(), false, Linkage,
2026  kODRGenPrefix + NameForGlobal, nullptr,
2027  NewGlobal->getThreadLocalMode());
2028 
2029  // Set meaningful attributes for indicator symbol.
2030  ODRIndicatorSym->setVisibility(NewGlobal->getVisibility());
2031  ODRIndicatorSym->setDLLStorageClass(NewGlobal->getDLLStorageClass());
2032  ODRIndicatorSym->setAlignment(1);
2033  ODRIndicator = ODRIndicatorSym;
2034  InstrumentedGlobal = GA;
2035  }
2036 
2037  Constant *Initializer = ConstantStruct::get(
2038  GlobalStructTy,
2039  ConstantExpr::getPointerCast(InstrumentedGlobal, IntptrTy),
2040  ConstantInt::get(IntptrTy, SizeInBytes),
2041  ConstantInt::get(IntptrTy, SizeInBytes + RightRedzoneSize),
2042  ConstantExpr::getPointerCast(Name, IntptrTy),
2043  ConstantExpr::getPointerCast(ModuleName, IntptrTy),
2044  ConstantInt::get(IntptrTy, MD.IsDynInit), SourceLoc,
2045  ConstantExpr::getPointerCast(ODRIndicator, IntptrTy));
2046 
2047  if (ClInitializers && MD.IsDynInit) HasDynamicallyInitializedGlobals = true;
2048 
2049  DEBUG(dbgs() << "NEW GLOBAL: " << *NewGlobal << "\n");
2050 
2051  Initializers[i] = Initializer;
2052  }
2053 
2054  std::string ELFUniqueModuleId =
2055  (UseGlobalsGC && TargetTriple.isOSBinFormatELF()) ? getUniqueModuleId(&M)
2056  : "";
2057 
2058  if (!ELFUniqueModuleId.empty()) {
2059  InstrumentGlobalsELF(IRB, M, NewGlobals, Initializers, ELFUniqueModuleId);
2060  *CtorComdat = true;
2061  } else if (UseGlobalsGC && TargetTriple.isOSBinFormatCOFF()) {
2062  InstrumentGlobalsCOFF(IRB, M, NewGlobals, Initializers);
2063  } else if (UseGlobalsGC && ShouldUseMachOGlobalsSection()) {
2064  InstrumentGlobalsMachO(IRB, M, NewGlobals, Initializers);
2065  } else {
2066  InstrumentGlobalsWithMetadataArray(IRB, M, NewGlobals, Initializers);
2067  }
2068 
2069  // Create calls for poisoning before initializers run and unpoisoning after.
2070  if (HasDynamicallyInitializedGlobals)
2071  createInitializerPoisonCalls(M, ModuleName);
2072 
2073  DEBUG(dbgs() << M);
2074  return true;
2075 }
2076 
2077 bool AddressSanitizerModule::runOnModule(Module &M) {
2078  C = &(M.getContext());
2079  int LongSize = M.getDataLayout().getPointerSizeInBits();
2080  IntptrTy = Type::getIntNTy(*C, LongSize);
2081  TargetTriple = Triple(M.getTargetTriple());
2082  Mapping = getShadowMapping(TargetTriple, LongSize, CompileKernel);
2083  initializeCallbacks(M);
2084 
2085  if (CompileKernel)
2086  return false;
2087 
2088  // Create a module constructor. A destructor is created lazily because not all
2089  // platforms, and not all modules need it.
2090  std::tie(AsanCtorFunction, std::ignore) = createSanitizerCtorAndInitFunctions(
2091  M, kAsanModuleCtorName, kAsanInitName, /*InitArgTypes=*/{},
2092  /*InitArgs=*/{}, kAsanVersionCheckName);
2093 
2094  bool CtorComdat = true;
2095  bool Changed = false;
2096  // TODO(glider): temporarily disabled globals instrumentation for KASan.
2097  if (ClGlobals) {
2098  IRBuilder<> IRB(AsanCtorFunction->getEntryBlock().getTerminator());
2099  Changed |= InstrumentGlobals(IRB, M, &CtorComdat);
2100  }
2101 
2102  // Put the constructor and destructor in comdat if both
2103  // (1) global instrumentation is not TU-specific
2104  // (2) target is ELF.
2105  if (UseCtorComdat && TargetTriple.isOSBinFormatELF() && CtorComdat) {
2106  AsanCtorFunction->setComdat(M.getOrInsertComdat(kAsanModuleCtorName));
2107  appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority,
2108  AsanCtorFunction);
2109  if (AsanDtorFunction) {
2110  AsanDtorFunction->setComdat(M.getOrInsertComdat(kAsanModuleDtorName));
2111  appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndDtorPriority,
2112  AsanDtorFunction);
2113  }
2114  } else {
2115  appendToGlobalCtors(M, AsanCtorFunction, kAsanCtorAndDtorPriority);
2116  if (AsanDtorFunction)
2117  appendToGlobalDtors(M, AsanDtorFunction, kAsanCtorAndDtorPriority);
2118  }
2119 
2120  return Changed;
2121 }
2122 
2123 void AddressSanitizer::initializeCallbacks(Module &M) {
2124  IRBuilder<> IRB(*C);
2125  // Create __asan_report* callbacks.
2126  // IsWrite, TypeSize and Exp are encoded in the function name.
2127  for (int Exp = 0; Exp < 2; Exp++) {
2128  for (size_t AccessIsWrite = 0; AccessIsWrite <= 1; AccessIsWrite++) {
2129  const std::string TypeStr = AccessIsWrite ? "store" : "load";
2130  const std::string ExpStr = Exp ? "exp_" : "";
2131  const std::string SuffixStr = CompileKernel ? "N" : "_n";
2132  const std::string EndingStr = Recover ? "_noabort" : "";
2133 
2134  SmallVector<Type *, 3> Args2 = {IntptrTy, IntptrTy};
2135  SmallVector<Type *, 2> Args1{1, IntptrTy};
2136  if (Exp) {
2137  Type *ExpType = Type::getInt32Ty(*C);
2138  Args2.push_back(ExpType);
2139  Args1.push_back(ExpType);
2140  }
2141  AsanErrorCallbackSized[AccessIsWrite][Exp] =
2143  kAsanReportErrorTemplate + ExpStr + TypeStr + SuffixStr +
2144  EndingStr,
2145  FunctionType::get(IRB.getVoidTy(), Args2, false)));
2146 
2147  AsanMemoryAccessCallbackSized[AccessIsWrite][Exp] =
2149  ClMemoryAccessCallbackPrefix + ExpStr + TypeStr + "N" + EndingStr,
2150  FunctionType::get(IRB.getVoidTy(), Args2, false)));
2151 
2152  for (size_t AccessSizeIndex = 0; AccessSizeIndex < kNumberOfAccessSizes;
2153  AccessSizeIndex++) {
2154  const std::string Suffix = TypeStr + itostr(1ULL << AccessSizeIndex);
2155  AsanErrorCallback[AccessIsWrite][Exp][AccessSizeIndex] =
2157  kAsanReportErrorTemplate + ExpStr + Suffix + EndingStr,
2158  FunctionType::get(IRB.getVoidTy(), Args1, false)));
2159 
2160  AsanMemoryAccessCallback[AccessIsWrite][Exp][AccessSizeIndex] =
2162  ClMemoryAccessCallbackPrefix + ExpStr + Suffix + EndingStr,
2163  FunctionType::get(IRB.getVoidTy(), Args1, false)));
2164  }
2165  }
2166  }
2167 
2168  const std::string MemIntrinCallbackPrefix =
2169  CompileKernel ? std::string("") : ClMemoryAccessCallbackPrefix;
2171  MemIntrinCallbackPrefix + "memmove", IRB.getInt8PtrTy(),
2172  IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy));
2174  MemIntrinCallbackPrefix + "memcpy", IRB.getInt8PtrTy(),
2175  IRB.getInt8PtrTy(), IRB.getInt8PtrTy(), IntptrTy));
2177  MemIntrinCallbackPrefix + "memset", IRB.getInt8PtrTy(),
2178  IRB.getInt8PtrTy(), IRB.getInt32Ty(), IntptrTy));
2179 
2180  AsanHandleNoReturnFunc = checkSanitizerInterfaceFunction(
2181  M.getOrInsertFunction(kAsanHandleNoReturnName, IRB.getVoidTy()));
2182 
2184  kAsanPtrCmp, IRB.getVoidTy(), IntptrTy, IntptrTy));
2186  kAsanPtrSub, IRB.getVoidTy(), IntptrTy, IntptrTy));
2187  // We insert an empty inline asm after __asan_report* to avoid callback merge.
2188  EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
2189  StringRef(""), StringRef(""),
2190  /*hasSideEffects=*/true);
2191 }
2192 
2193 // virtual
2194 bool AddressSanitizer::doInitialization(Module &M) {
2195  // Initialize the private fields. No one has accessed them before.
2196  GlobalsMD.init(M);
2197 
2198  C = &(M.getContext());
2199  LongSize = M.getDataLayout().getPointerSizeInBits();
2200  IntptrTy = Type::getIntNTy(*C, LongSize);
2201  TargetTriple = Triple(M.getTargetTriple());
2202 
2203  Mapping = getShadowMapping(TargetTriple, LongSize, CompileKernel);
2204  return true;
2205 }
2206 
2207 bool AddressSanitizer::doFinalization(Module &M) {
2208  GlobalsMD.reset();
2209  return false;
2210 }
2211 
2212 bool AddressSanitizer::maybeInsertAsanInitAtFunctionEntry(Function &F) {
2213  // For each NSObject descendant having a +load method, this method is invoked
2214  // by the ObjC runtime before any of the static constructors is called.
2215  // Therefore we need to instrument such methods with a call to __asan_init
2216  // at the beginning in order to initialize our runtime before any access to
2217  // the shadow memory.
2218  // We cannot just ignore these methods, because they may call other
2219  // instrumented functions.
2220  if (F.getName().find(" load]") != std::string::npos) {
2221  Function *AsanInitFunction =
2223  IRBuilder<> IRB(&F.front(), F.front().begin());
2224  IRB.CreateCall(AsanInitFunction, {});
2225  return true;
2226  }
2227  return false;
2228 }
2229 
2230 void AddressSanitizer::maybeInsertDynamicShadowAtFunctionEntry(Function &F) {
2231  // Generate code only when dynamic addressing is needed.
2232  if (Mapping.Offset != kDynamicShadowSentinel)
2233  return;
2234 
2235  IRBuilder<> IRB(&F.front().front());
2236  Value *GlobalDynamicAddress = F.getParent()->getOrInsertGlobal(
2237  kAsanShadowMemoryDynamicAddress, IntptrTy);
2238  LocalDynamicShadow = IRB.CreateLoad(GlobalDynamicAddress);
2239 }
2240 
2241 void AddressSanitizer::markEscapedLocalAllocas(Function &F) {
2242  // Find the one possible call to llvm.localescape and pre-mark allocas passed
2243  // to it as uninteresting. This assumes we haven't started processing allocas
2244  // yet. This check is done up front because iterating the use list in
2245  // isInterestingAlloca would be algorithmically slower.
2246  assert(ProcessedAllocas.empty() && "must process localescape before allocas");
2247 
2248  // Try to get the declaration of llvm.localescape. If it's not in the module,
2249  // we can exit early.
2250  if (!F.getParent()->getFunction("llvm.localescape")) return;
2251 
2252  // Look for a call to llvm.localescape call in the entry block. It can't be in
2253  // any other block.
2254  for (Instruction &I : F.getEntryBlock()) {
2256  if (II && II->getIntrinsicID() == Intrinsic::localescape) {
2257  // We found a call. Mark all the allocas passed in as uninteresting.
2258  for (Value *Arg : II->arg_operands()) {
2260  assert(AI && AI->isStaticAlloca() &&
2261  "non-static alloca arg to localescape");
2262  ProcessedAllocas[AI] = false;
2263  }
2264  break;
2265  }
2266  }
2267 }
2268 
2269 bool AddressSanitizer::runOnFunction(Function &F) {
2270  if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) return false;
2271  if (!ClDebugFunc.empty() && ClDebugFunc == F.getName()) return false;
2272  if (F.getName().startswith("__asan_")) return false;
2273 
2274  bool FunctionModified = false;
2275 
2276  // If needed, insert __asan_init before checking for SanitizeAddress attr.
2277  // This function needs to be called even if the function body is not
2278  // instrumented.
2279  if (maybeInsertAsanInitAtFunctionEntry(F))
2280  FunctionModified = true;
2281 
2282  // Leave if the function doesn't need instrumentation.
2283  if (!F.hasFnAttribute(Attribute::SanitizeAddress)) return FunctionModified;
2284 
2285  DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
2286 
2287  initializeCallbacks(*F.getParent());
2288  DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
2289 
2290  FunctionStateRAII CleanupObj(this);
2291 
2292  maybeInsertDynamicShadowAtFunctionEntry(F);
2293 
2294  // We can't instrument allocas used with llvm.localescape. Only static allocas
2295  // can be passed to that intrinsic.
2296  markEscapedLocalAllocas(F);
2297 
2298  // We want to instrument every address only once per basic block (unless there
2299  // are calls between uses).
2300  SmallSet<Value *, 16> TempsToInstrument;
2301  SmallVector<Instruction *, 16> ToInstrument;
2302  SmallVector<Instruction *, 8> NoReturnCalls;
2304  SmallVector<Instruction *, 16> PointerComparisonsOrSubtracts;
2305  int NumAllocas = 0;
2306  bool IsWrite;
2307  unsigned Alignment;
2308  uint64_t TypeSize;
2309  const TargetLibraryInfo *TLI =
2310  &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
2311 
2312  // Fill the set of memory operations to instrument.
2313  for (auto &BB : F) {
2314  AllBlocks.push_back(&BB);
2315  TempsToInstrument.clear();
2316  int NumInsnsPerBB = 0;
2317  for (auto &Inst : BB) {
2318  if (LooksLikeCodeInBug11395(&Inst)) return false;
2319  Value *MaybeMask = nullptr;
2320  if (Value *Addr = isInterestingMemoryAccess(&Inst, &IsWrite, &TypeSize,
2321  &Alignment, &MaybeMask)) {
2322  if (ClOpt && ClOptSameTemp) {
2323  // If we have a mask, skip instrumentation if we've already
2324  // instrumented the full object. But don't add to TempsToInstrument
2325  // because we might get another load/store with a different mask.
2326  if (MaybeMask) {
2327  if (TempsToInstrument.count(Addr))
2328  continue; // We've seen this (whole) temp in the current BB.
2329  } else {
2330  if (!TempsToInstrument.insert(Addr).second)
2331  continue; // We've seen this temp in the current BB.
2332  }
2333  }
2334  } else if (ClInvalidPointerPairs &&
2336  PointerComparisonsOrSubtracts.push_back(&Inst);
2337  continue;
2338  } else if (isa<MemIntrinsic>(Inst)) {
2339  // ok, take it.
2340  } else {
2341  if (isa<AllocaInst>(Inst)) NumAllocas++;
2342  CallSite CS(&Inst);
2343  if (CS) {
2344  // A call inside BB.
2345  TempsToInstrument.clear();
2346  if (CS.doesNotReturn()) NoReturnCalls.push_back(CS.getInstruction());
2347  }
2348  if (CallInst *CI = dyn_cast<CallInst>(&Inst))
2350  continue;
2351  }
2352  ToInstrument.push_back(&Inst);
2353  NumInsnsPerBB++;
2354  if (NumInsnsPerBB >= ClMaxInsnsToInstrumentPerBB) break;
2355  }
2356  }
2357 
2358  bool UseCalls =
2359  CompileKernel ||
2362  const DataLayout &DL = F.getParent()->getDataLayout();
2363  ObjectSizeOpts ObjSizeOpts;
2364  ObjSizeOpts.RoundToAlign = true;
2365  ObjectSizeOffsetVisitor ObjSizeVis(DL, TLI, F.getContext(), ObjSizeOpts);
2366 
2367  // Instrument.
2368  int NumInstrumented = 0;
2369  for (auto Inst : ToInstrument) {
2370  if (ClDebugMin < 0 || ClDebugMax < 0 ||
2371  (NumInstrumented >= ClDebugMin && NumInstrumented <= ClDebugMax)) {
2372  if (isInterestingMemoryAccess(Inst, &IsWrite, &TypeSize, &Alignment))
2373  instrumentMop(ObjSizeVis, Inst, UseCalls,
2374  F.getParent()->getDataLayout());
2375  else
2376  instrumentMemIntrinsic(cast<MemIntrinsic>(Inst));
2377  }
2378  NumInstrumented++;
2379  }
2380 
2381  FunctionStackPoisoner FSP(F, *this);
2382  bool ChangedStack = FSP.runOnFunction();
2383 
2384  // We must unpoison the stack before every NoReturn call (throw, _exit, etc).
2385  // See e.g. http://code.google.com/p/address-sanitizer/issues/detail?id=37
2386  for (auto CI : NoReturnCalls) {
2387  IRBuilder<> IRB(CI);
2388  IRB.CreateCall(AsanHandleNoReturnFunc, {});
2389  }
2390 
2391  for (auto Inst : PointerComparisonsOrSubtracts) {
2392  instrumentPointerComparisonOrSubtraction(Inst);
2393  NumInstrumented++;
2394  }
2395 
2396  if (NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty())
2397  FunctionModified = true;
2398 
2399  DEBUG(dbgs() << "ASAN done instrumenting: " << FunctionModified << " "
2400  << F << "\n");
2401 
2402  return FunctionModified;
2403 }
2404 
2405 // Workaround for bug 11395: we don't want to instrument stack in functions
2406 // with large assembly blobs (32-bit only), otherwise reg alloc may crash.
2407 // FIXME: remove once the bug 11395 is fixed.
2408 bool AddressSanitizer::LooksLikeCodeInBug11395(Instruction *I) {
2409  if (LongSize != 32) return false;
2410  CallInst *CI = dyn_cast<CallInst>(I);
2411  if (!CI || !CI->isInlineAsm()) return false;
2412  if (CI->getNumArgOperands() <= 5) return false;
2413  // We have inline assembly with quite a few arguments.
2414  return true;
2415 }
2416 
2417 void FunctionStackPoisoner::initializeCallbacks(Module &M) {
2418  IRBuilder<> IRB(*C);
2419  for (int i = 0; i <= kMaxAsanStackMallocSizeClass; i++) {
2420  std::string Suffix = itostr(i);
2421  AsanStackMallocFunc[i] = checkSanitizerInterfaceFunction(
2422  M.getOrInsertFunction(kAsanStackMallocNameTemplate + Suffix, IntptrTy,
2423  IntptrTy));
2424  AsanStackFreeFunc[i] = checkSanitizerInterfaceFunction(
2425  M.getOrInsertFunction(kAsanStackFreeNameTemplate + Suffix,
2426  IRB.getVoidTy(), IntptrTy, IntptrTy));
2427  }
2428  if (ASan.UseAfterScope) {
2429  AsanPoisonStackMemoryFunc = checkSanitizerInterfaceFunction(
2430  M.getOrInsertFunction(kAsanPoisonStackMemoryName, IRB.getVoidTy(),
2431  IntptrTy, IntptrTy));
2432  AsanUnpoisonStackMemoryFunc = checkSanitizerInterfaceFunction(
2433  M.getOrInsertFunction(kAsanUnpoisonStackMemoryName, IRB.getVoidTy(),
2434  IntptrTy, IntptrTy));
2435  }
2436 
2437  for (size_t Val : {0x00, 0xf1, 0xf2, 0xf3, 0xf5, 0xf8}) {
2438  std::ostringstream Name;
2439  Name << kAsanSetShadowPrefix;
2440  Name << std::setw(2) << std::setfill('0') << std::hex << Val;
2441  AsanSetShadowFunc[Val] =
2443  Name.str(), IRB.getVoidTy(), IntptrTy, IntptrTy));
2444  }
2445 
2446  AsanAllocaPoisonFunc = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
2447  kAsanAllocaPoison, IRB.getVoidTy(), IntptrTy, IntptrTy));
2448  AsanAllocasUnpoisonFunc =
2450  kAsanAllocasUnpoison, IRB.getVoidTy(), IntptrTy, IntptrTy));
2451 }
2452 
2453 void FunctionStackPoisoner::copyToShadowInline(ArrayRef<uint8_t> ShadowMask,
2454  ArrayRef<uint8_t> ShadowBytes,
2455  size_t Begin, size_t End,
2456  IRBuilder<> &IRB,
2457  Value *ShadowBase) {
2458  if (Begin >= End)
2459  return;
2460 
2461  const size_t LargestStoreSizeInBytes =
2462  std::min<size_t>(sizeof(uint64_t), ASan.LongSize / 8);
2463 
2464  const bool IsLittleEndian = F.getParent()->getDataLayout().isLittleEndian();
2465 
2466  // Poison given range in shadow using larges store size with out leading and
2467  // trailing zeros in ShadowMask. Zeros never change, so they need neither
2468  // poisoning nor up-poisoning. Still we don't mind if some of them get into a
2469  // middle of a store.
2470  for (size_t i = Begin; i < End;) {
2471  if (!ShadowMask[i]) {
2472  assert(!ShadowBytes[i]);
2473  ++i;
2474  continue;
2475  }
2476 
2477  size_t StoreSizeInBytes = LargestStoreSizeInBytes;
2478  // Fit store size into the range.
2479  while (StoreSizeInBytes > End - i)
2480  StoreSizeInBytes /= 2;
2481 
2482  // Minimize store size by trimming trailing zeros.
2483  for (size_t j = StoreSizeInBytes - 1; j && !ShadowMask[i + j]; --j) {
2484  while (j <= StoreSizeInBytes / 2)
2485  StoreSizeInBytes /= 2;
2486  }
2487 
2488  uint64_t Val = 0;
2489  for (size_t j = 0; j < StoreSizeInBytes; j++) {
2490  if (IsLittleEndian)
2491  Val |= (uint64_t)ShadowBytes[i + j] << (8 * j);
2492  else
2493  Val = (Val << 8) | ShadowBytes[i + j];
2494  }
2495 
2496  Value *Ptr = IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i));
2497  Value *Poison = IRB.getIntN(StoreSizeInBytes * 8, Val);
2498  IRB.CreateAlignedStore(
2499  Poison, IRB.CreateIntToPtr(Ptr, Poison->getType()->getPointerTo()), 1);
2500 
2501  i += StoreSizeInBytes;
2502  }
2503 }
2504 
2505 void FunctionStackPoisoner::copyToShadow(ArrayRef<uint8_t> ShadowMask,
2506  ArrayRef<uint8_t> ShadowBytes,
2507  IRBuilder<> &IRB, Value *ShadowBase) {
2508  copyToShadow(ShadowMask, ShadowBytes, 0, ShadowMask.size(), IRB, ShadowBase);
2509 }
2510 
2511 void FunctionStackPoisoner::copyToShadow(ArrayRef<uint8_t> ShadowMask,
2512  ArrayRef<uint8_t> ShadowBytes,
2513  size_t Begin, size_t End,
2514  IRBuilder<> &IRB, Value *ShadowBase) {
2515  assert(ShadowMask.size() == ShadowBytes.size());
2516  size_t Done = Begin;
2517  for (size_t i = Begin, j = Begin + 1; i < End; i = j++) {
2518  if (!ShadowMask[i]) {
2519  assert(!ShadowBytes[i]);
2520  continue;
2521  }
2522  uint8_t Val = ShadowBytes[i];
2523  if (!AsanSetShadowFunc[Val])
2524  continue;
2525 
2526  // Skip same values.
2527  for (; j < End && ShadowMask[j] && Val == ShadowBytes[j]; ++j) {
2528  }
2529 
2530  if (j - i >= ClMaxInlinePoisoningSize) {
2531  copyToShadowInline(ShadowMask, ShadowBytes, Done, i, IRB, ShadowBase);
2532  IRB.CreateCall(AsanSetShadowFunc[Val],
2533  {IRB.CreateAdd(ShadowBase, ConstantInt::get(IntptrTy, i)),
2534  ConstantInt::get(IntptrTy, j - i)});
2535  Done = j;
2536  }
2537  }
2538 
2539  copyToShadowInline(ShadowMask, ShadowBytes, Done, End, IRB, ShadowBase);
2540 }
2541 
2542 // Fake stack allocator (asan_fake_stack.h) has 11 size classes
2543 // for every power of 2 from kMinStackMallocSize to kMaxAsanStackMallocSizeClass
2544 static int StackMallocSizeClass(uint64_t LocalStackSize) {
2545  assert(LocalStackSize <= kMaxStackMallocSize);
2546  uint64_t MaxSize = kMinStackMallocSize;
2547  for (int i = 0;; i++, MaxSize *= 2)
2548  if (LocalStackSize <= MaxSize) return i;
2549  llvm_unreachable("impossible LocalStackSize");
2550 }
2551 
2552 void FunctionStackPoisoner::copyArgsPassedByValToAllocas() {
2553  Instruction *CopyInsertPoint = &F.front().front();
2554  if (CopyInsertPoint == ASan.LocalDynamicShadow) {
2555  // Insert after the dynamic shadow location is determined
2556  CopyInsertPoint = CopyInsertPoint->getNextNode();
2557  assert(CopyInsertPoint);
2558  }
2559  IRBuilder<> IRB(CopyInsertPoint);
2560  const DataLayout &DL = F.getParent()->getDataLayout();
2561  for (Argument &Arg : F.args()) {
2562  if (Arg.hasByValAttr()) {
2564  unsigned Align = Arg.getParamAlignment();
2565  if (Align == 0) Align = DL.getABITypeAlignment(Ty);
2566 
2567  const std::string &Name = Arg.hasName() ? Arg.getName().str() :
2568  "Arg" + llvm::to_string(Arg.getArgNo());
2569  AllocaInst *AI = IRB.CreateAlloca(Ty, nullptr, Twine(Name) + ".byval");
2570  AI->setAlignment(Align);
2571  Arg.replaceAllUsesWith(AI);
2572 
2573  uint64_t AllocSize = DL.getTypeAllocSize(Ty);
2574  IRB.CreateMemCpy(AI, &Arg, AllocSize, Align);
2575  }
2576  }
2577 }
2578 
2579 PHINode *FunctionStackPoisoner::createPHI(IRBuilder<> &IRB, Value *Cond,
2580  Value *ValueIfTrue,
2581  Instruction *ThenTerm,
2582  Value *ValueIfFalse) {
2583  PHINode *PHI = IRB.CreatePHI(IntptrTy, 2);
2584  BasicBlock *CondBlock = cast<Instruction>(Cond)->getParent();
2585  PHI->addIncoming(ValueIfFalse, CondBlock);
2586  BasicBlock *ThenBlock = ThenTerm->getParent();
2587  PHI->addIncoming(ValueIfTrue, ThenBlock);
2588  return PHI;
2589 }
2590 
2591 Value *FunctionStackPoisoner::createAllocaForLayout(
2592  IRBuilder<> &IRB, const ASanStackFrameLayout &L, bool Dynamic) {
2593  AllocaInst *Alloca;
2594  if (Dynamic) {
2595  Alloca = IRB.CreateAlloca(IRB.getInt8Ty(),
2597  "MyAlloca");
2598  } else {
2599  Alloca = IRB.CreateAlloca(ArrayType::get(IRB.getInt8Ty(), L.FrameSize),
2600  nullptr, "MyAlloca");
2601  assert(Alloca->isStaticAlloca());
2602  }
2603  assert((ClRealignStack & (ClRealignStack - 1)) == 0);
2604  size_t FrameAlignment = std::max(L.FrameAlignment, (size_t)ClRealignStack);
2605  Alloca->setAlignment(FrameAlignment);
2606  return IRB.CreatePointerCast(Alloca, IntptrTy);
2607 }
2608 
2609 void FunctionStackPoisoner::createDynamicAllocasInitStorage() {
2610  BasicBlock &FirstBB = *F.begin();
2611  IRBuilder<> IRB(dyn_cast<Instruction>(FirstBB.begin()));
2612  DynamicAllocaLayout = IRB.CreateAlloca(IntptrTy, nullptr);
2613  IRB.CreateStore(Constant::getNullValue(IntptrTy), DynamicAllocaLayout);
2614  DynamicAllocaLayout->setAlignment(32);
2615 }
2616 
2617 void FunctionStackPoisoner::processDynamicAllocas() {
2618  if (!ClInstrumentDynamicAllocas || DynamicAllocaVec.empty()) {
2619  assert(DynamicAllocaPoisonCallVec.empty());
2620  return;
2621  }
2622 
2623  // Insert poison calls for lifetime intrinsics for dynamic allocas.
2624  for (const auto &APC : DynamicAllocaPoisonCallVec) {
2625  assert(APC.InsBefore);
2626  assert(APC.AI);
2627  assert(ASan.isInterestingAlloca(*APC.AI));
2628  assert(!APC.AI->isStaticAlloca());
2629 
2630  IRBuilder<> IRB(APC.InsBefore);
2631  poisonAlloca(APC.AI, APC.Size, IRB, APC.DoPoison);
2632  // Dynamic allocas will be unpoisoned unconditionally below in
2633  // unpoisonDynamicAllocas.
2634  // Flag that we need unpoison static allocas.
2635  }
2636 
2637  // Handle dynamic allocas.
2638  createDynamicAllocasInitStorage();
2639  for (auto &AI : DynamicAllocaVec)
2640  handleDynamicAllocaCall(AI);
2641  unpoisonDynamicAllocas();
2642 }
2643 
2644 void FunctionStackPoisoner::processStaticAllocas() {
2645  if (AllocaVec.empty()) {
2646  assert(StaticAllocaPoisonCallVec.empty());
2647  return;
2648  }
2649 
2650  int StackMallocIdx = -1;
2651  DebugLoc EntryDebugLocation;
2652  if (auto SP = F.getSubprogram())
2653  EntryDebugLocation = DebugLoc::get(SP->getScopeLine(), 0, SP);
2654 
2655  Instruction *InsBefore = AllocaVec[0];
2656  IRBuilder<> IRB(InsBefore);
2657  IRB.SetCurrentDebugLocation(EntryDebugLocation);
2658 
2659  // Make sure non-instrumented allocas stay in the entry block. Otherwise,
2660  // debug info is broken, because only entry-block allocas are treated as
2661  // regular stack slots.
2662  auto InsBeforeB = InsBefore->getParent();
2663  assert(InsBeforeB == &F.getEntryBlock());
2664  for (auto *AI : StaticAllocasToMoveUp)
2665  if (AI->getParent() == InsBeforeB)
2666  AI->moveBefore(InsBefore);
2667 
2668  // If we have a call to llvm.localescape, keep it in the entry block.
2669  if (LocalEscapeCall) LocalEscapeCall->moveBefore(InsBefore);
2670 
2672  SVD.reserve(AllocaVec.size());
2673  for (AllocaInst *AI : AllocaVec) {
2675  ASan.getAllocaSizeInBytes(*AI),
2676  0,
2677  AI->getAlignment(),
2678  AI,
2679  0,
2680  0};
2681  SVD.push_back(D);
2682  }
2683 
2684  // Minimal header size (left redzone) is 4 pointers,
2685  // i.e. 32 bytes on 64-bit platforms and 16 bytes in 32-bit platforms.
2686  size_t MinHeaderSize = ASan.LongSize / 2;
2687  const ASanStackFrameLayout &L =
2688  ComputeASanStackFrameLayout(SVD, 1ULL << Mapping.Scale, MinHeaderSize);
2689 
2690  // Build AllocaToSVDMap for ASanStackVariableDescription lookup.
2692  for (auto &Desc : SVD)
2693  AllocaToSVDMap[Desc.AI] = &Desc;
2694 
2695  // Update SVD with information from lifetime intrinsics.
2696  for (const auto &APC : StaticAllocaPoisonCallVec) {
2697  assert(APC.InsBefore);
2698  assert(APC.AI);
2699  assert(ASan.isInterestingAlloca(*APC.AI));
2700  assert(APC.AI->isStaticAlloca());
2701 
2702  ASanStackVariableDescription &Desc = *AllocaToSVDMap[APC.AI];
2703  Desc.LifetimeSize = Desc.Size;
2704  if (const DILocation *FnLoc = EntryDebugLocation.get()) {
2705  if (const DILocation *LifetimeLoc = APC.InsBefore->getDebugLoc().get()) {
2706  if (LifetimeLoc->getFile() == FnLoc->getFile())
2707  if (unsigned Line = LifetimeLoc->getLine())
2708  Desc.Line = std::min(Desc.Line ? Desc.Line : Line, Line);
2709  }
2710  }
2711  }
2712 
2713  auto DescriptionString = ComputeASanStackFrameDescription(SVD);
2714  DEBUG(dbgs() << DescriptionString << " --- " << L.FrameSize << "\n");
2715  uint64_t LocalStackSize = L.FrameSize;
2716  bool DoStackMalloc = ClUseAfterReturn && !ASan.CompileKernel &&
2717  LocalStackSize <= kMaxStackMallocSize;
2718  bool DoDynamicAlloca = ClDynamicAllocaStack;
2719  // Don't do dynamic alloca or stack malloc if:
2720  // 1) There is inline asm: too often it makes assumptions on which registers
2721  // are available.
2722  // 2) There is a returns_twice call (typically setjmp), which is
2723  // optimization-hostile, and doesn't play well with introduced indirect
2724  // register-relative calculation of local variable addresses.
2725  DoDynamicAlloca &= !HasNonEmptyInlineAsm && !HasReturnsTwiceCall;
2726  DoStackMalloc &= !HasNonEmptyInlineAsm && !HasReturnsTwiceCall;
2727 
2728  Value *StaticAlloca =
2729  DoDynamicAlloca ? nullptr : createAllocaForLayout(IRB, L, false);
2730 
2731  Value *FakeStack;
2732  Value *LocalStackBase;
2733 
2734  if (DoStackMalloc) {
2735  // void *FakeStack = __asan_option_detect_stack_use_after_return
2736  // ? __asan_stack_malloc_N(LocalStackSize)
2737  // : nullptr;
2738  // void *LocalStackBase = (FakeStack) ? FakeStack : alloca(LocalStackSize);
2739  Constant *OptionDetectUseAfterReturn = F.getParent()->getOrInsertGlobal(
2740  kAsanOptionDetectUseAfterReturn, IRB.getInt32Ty());
2741  Value *UseAfterReturnIsEnabled =
2742  IRB.CreateICmpNE(IRB.CreateLoad(OptionDetectUseAfterReturn),
2744  Instruction *Term =
2745  SplitBlockAndInsertIfThen(UseAfterReturnIsEnabled, InsBefore, false);
2746  IRBuilder<> IRBIf(Term);
2747  IRBIf.SetCurrentDebugLocation(EntryDebugLocation);
2748  StackMallocIdx = StackMallocSizeClass(LocalStackSize);
2749  assert(StackMallocIdx <= kMaxAsanStackMallocSizeClass);
2750  Value *FakeStackValue =
2751  IRBIf.CreateCall(AsanStackMallocFunc[StackMallocIdx],
2752  ConstantInt::get(IntptrTy, LocalStackSize));
2753  IRB.SetInsertPoint(InsBefore);
2754  IRB.SetCurrentDebugLocation(EntryDebugLocation);
2755  FakeStack = createPHI(IRB, UseAfterReturnIsEnabled, FakeStackValue, Term,
2756  ConstantInt::get(IntptrTy, 0));
2757 
2758  Value *NoFakeStack =
2759  IRB.CreateICmpEQ(FakeStack, Constant::getNullValue(IntptrTy));
2760  Term = SplitBlockAndInsertIfThen(NoFakeStack, InsBefore, false);
2761  IRBIf.SetInsertPoint(Term);
2762  IRBIf.SetCurrentDebugLocation(EntryDebugLocation);
2763  Value *AllocaValue =
2764  DoDynamicAlloca ? createAllocaForLayout(IRBIf, L, true) : StaticAlloca;
2765  IRB.SetInsertPoint(InsBefore);
2766  IRB.SetCurrentDebugLocation(EntryDebugLocation);
2767  LocalStackBase = createPHI(IRB, NoFakeStack, AllocaValue, Term, FakeStack);
2768  } else {
2769  // void *FakeStack = nullptr;
2770  // void *LocalStackBase = alloca(LocalStackSize);
2771  FakeStack = ConstantInt::get(IntptrTy, 0);
2772  LocalStackBase =
2773  DoDynamicAlloca ? createAllocaForLayout(IRB, L, true) : StaticAlloca;
2774  }
2775 
2776  // Replace Alloca instructions with base+offset.
2777  for (const auto &Desc : SVD) {
2778  AllocaInst *AI = Desc.AI;
2779  Value *NewAllocaPtr = IRB.CreateIntToPtr(
2780  IRB.CreateAdd(LocalStackBase, ConstantInt::get(IntptrTy, Desc.Offset)),
2781  AI->getType());
2782  replaceDbgDeclareForAlloca(AI, NewAllocaPtr, DIB, DIExpression::NoDeref);
2783  AI->replaceAllUsesWith(NewAllocaPtr);
2784  }
2785 
2786  // The left-most redzone has enough space for at least 4 pointers.
2787  // Write the Magic value to redzone[0].
2788  Value *BasePlus0 = IRB.CreateIntToPtr(LocalStackBase, IntptrPtrTy);
2790  BasePlus0);
2791  // Write the frame description constant to redzone[1].
2792  Value *BasePlus1 = IRB.CreateIntToPtr(
2793  IRB.CreateAdd(LocalStackBase,
2794  ConstantInt::get(IntptrTy, ASan.LongSize / 8)),
2795  IntptrPtrTy);
2796  GlobalVariable *StackDescriptionGlobal =
2797  createPrivateGlobalForString(*F.getParent(), DescriptionString,
2798  /*AllowMerging*/ true);
2799  Value *Description = IRB.CreatePointerCast(StackDescriptionGlobal, IntptrTy);
2800  IRB.CreateStore(Description, BasePlus1);
2801  // Write the PC to redzone[2].
2802  Value *BasePlus2 = IRB.CreateIntToPtr(
2803  IRB.CreateAdd(LocalStackBase,
2804  ConstantInt::get(IntptrTy, 2 * ASan.LongSize / 8)),
2805  IntptrPtrTy);
2806  IRB.CreateStore(IRB.CreatePointerCast(&F, IntptrTy), BasePlus2);
2807 
2808  const auto &ShadowAfterScope = GetShadowBytesAfterScope(SVD, L);
2809 
2810  // Poison the stack red zones at the entry.
2811  Value *ShadowBase = ASan.memToShadow(LocalStackBase, IRB);
2812  // As mask we must use most poisoned case: red zones and after scope.
2813  // As bytes we can use either the same or just red zones only.
2814  copyToShadow(ShadowAfterScope, ShadowAfterScope, IRB, ShadowBase);
2815 
2816  if (!StaticAllocaPoisonCallVec.empty()) {
2817  const auto &ShadowInScope = GetShadowBytes(SVD, L);
2818 
2819  // Poison static allocas near lifetime intrinsics.
2820  for (const auto &APC : StaticAllocaPoisonCallVec) {
2821  const ASanStackVariableDescription &Desc = *AllocaToSVDMap[APC.AI];
2822  assert(Desc.Offset % L.Granularity == 0);
2823  size_t Begin = Desc.Offset / L.Granularity;
2824  size_t End = Begin + (APC.Size + L.Granularity - 1) / L.Granularity;
2825 
2826  IRBuilder<> IRB(APC.InsBefore);
2827  copyToShadow(ShadowAfterScope,
2828  APC.DoPoison ? ShadowAfterScope : ShadowInScope, Begin, End,
2829  IRB, ShadowBase);
2830  }
2831  }
2832 
2833  SmallVector<uint8_t, 64> ShadowClean(ShadowAfterScope.size(), 0);
2834  SmallVector<uint8_t, 64> ShadowAfterReturn;
2835 
2836  // (Un)poison the stack before all ret instructions.
2837  for (auto Ret : RetVec) {
2838  IRBuilder<> IRBRet(Ret);
2839  // Mark the current frame as retired.
2841  BasePlus0);
2842  if (DoStackMalloc) {
2843  assert(StackMallocIdx >= 0);
2844  // if FakeStack != 0 // LocalStackBase == FakeStack
2845  // // In use-after-return mode, poison the whole stack frame.
2846  // if StackMallocIdx <= 4
2847  // // For small sizes inline the whole thing:
2848  // memset(ShadowBase, kAsanStackAfterReturnMagic, ShadowSize);
2849  // **SavedFlagPtr(FakeStack) = 0
2850  // else
2851  // __asan_stack_free_N(FakeStack, LocalStackSize)
2852  // else
2853  // <This is not a fake stack; unpoison the redzones>
2854  Value *Cmp =
2855  IRBRet.CreateICmpNE(FakeStack, Constant::getNullValue(IntptrTy));
2856  TerminatorInst *ThenTerm, *ElseTerm;
2857  SplitBlockAndInsertIfThenElse(Cmp, Ret, &ThenTerm, &ElseTerm);
2858 
2859  IRBuilder<> IRBPoison(ThenTerm);
2860  if (StackMallocIdx <= 4) {
2861  int ClassSize = kMinStackMallocSize << StackMallocIdx;
2862  ShadowAfterReturn.resize(ClassSize / L.Granularity,
2864  copyToShadow(ShadowAfterReturn, ShadowAfterReturn, IRBPoison,
2865  ShadowBase);
2866  Value *SavedFlagPtrPtr = IRBPoison.CreateAdd(
2867  FakeStack,
2868  ConstantInt::get(IntptrTy, ClassSize - ASan.LongSize / 8));
2869  Value *SavedFlagPtr = IRBPoison.CreateLoad(
2870  IRBPoison.CreateIntToPtr(SavedFlagPtrPtr, IntptrPtrTy));
2871  IRBPoison.CreateStore(
2872  Constant::getNullValue(IRBPoison.getInt8Ty()),
2873  IRBPoison.CreateIntToPtr(SavedFlagPtr, IRBPoison.getInt8PtrTy()));
2874  } else {
2875  // For larger frames call __asan_stack_free_*.
2876  IRBPoison.CreateCall(
2877  AsanStackFreeFunc[StackMallocIdx],
2878  {FakeStack, ConstantInt::get(IntptrTy, LocalStackSize)});
2879  }
2880 
2881  IRBuilder<> IRBElse(ElseTerm);
2882  copyToShadow(ShadowAfterScope, ShadowClean, IRBElse, ShadowBase);
2883  } else {
2884  copyToShadow(ShadowAfterScope, ShadowClean, IRBRet, ShadowBase);
2885  }
2886  }
2887 
2888  // We are done. Remove the old unused alloca instructions.
2889  for (auto AI : AllocaVec) AI->eraseFromParent();
2890 }
2891 
2892 void FunctionStackPoisoner::poisonAlloca(Value *V, uint64_t Size,
2893  IRBuilder<> &IRB, bool DoPoison) {
2894  // For now just insert the call to ASan runtime.
2895  Value *AddrArg = IRB.CreatePointerCast(V, IntptrTy);
2896  Value *SizeArg = ConstantInt::get(IntptrTy, Size);
2897  IRB.CreateCall(
2898  DoPoison ? AsanPoisonStackMemoryFunc : AsanUnpoisonStackMemoryFunc,
2899  {AddrArg, SizeArg});
2900 }
2901 
2902 // Handling llvm.lifetime intrinsics for a given %alloca:
2903 // (1) collect all llvm.lifetime.xxx(%size, %value) describing the alloca.
2904 // (2) if %size is constant, poison memory for llvm.lifetime.end (to detect
2905 // invalid accesses) and unpoison it for llvm.lifetime.start (the memory
2906 // could be poisoned by previous llvm.lifetime.end instruction, as the
2907 // variable may go in and out of scope several times, e.g. in loops).
2908 // (3) if we poisoned at least one %alloca in a function,
2909 // unpoison the whole stack frame at function exit.
2910 
2911 AllocaInst *FunctionStackPoisoner::findAllocaForValue(Value *V) {
2912  if (AllocaInst *AI = dyn_cast<AllocaInst>(V))
2913  // We're interested only in allocas we can handle.
2914  return ASan.isInterestingAlloca(*AI) ? AI : nullptr;
2915  // See if we've already calculated (or started to calculate) alloca for a
2916  // given value.
2917  AllocaForValueMapTy::iterator I = AllocaForValue.find(V);
2918  if (I != AllocaForValue.end()) return I->second;
2919  // Store 0 while we're calculating alloca for value V to avoid
2920  // infinite recursion if the value references itself.
2921  AllocaForValue[V] = nullptr;
2922  AllocaInst *Res = nullptr;
2923  if (CastInst *CI = dyn_cast<CastInst>(V))
2924  Res = findAllocaForValue(CI->getOperand(0));
2925  else if (PHINode *PN = dyn_cast<PHINode>(V)) {
2926  for (Value *IncValue : PN->incoming_values()) {
2927  // Allow self-referencing phi-nodes.
2928  if (IncValue == PN) continue;
2929  AllocaInst *IncValueAI = findAllocaForValue(IncValue);
2930  // AI for incoming values should exist and should all be equal.
2931  if (IncValueAI == nullptr || (Res != nullptr && IncValueAI != Res))
2932  return nullptr;
2933  Res = IncValueAI;
2934  }
2935  } else if (GetElementPtrInst *EP = dyn_cast<GetElementPtrInst>(V)) {
2936  Res = findAllocaForValue(EP->getPointerOperand());
2937  } else {
2938  DEBUG(dbgs() << "Alloca search canceled on unknown instruction: " << *V << "\n");
2939  }
2940  if (Res) AllocaForValue[V] = Res;
2941  return Res;
2942 }
2943 
2944 void FunctionStackPoisoner::handleDynamicAllocaCall(AllocaInst *AI) {
2945  IRBuilder<> IRB(AI);
2946 
2947  const unsigned Align = std::max(kAllocaRzSize, AI->getAlignment());
2948  const uint64_t AllocaRedzoneMask = kAllocaRzSize - 1;
2949 
2950  Value *Zero = Constant::getNullValue(IntptrTy);
2951  Value *AllocaRzSize = ConstantInt::get(IntptrTy, kAllocaRzSize);
2952  Value *AllocaRzMask = ConstantInt::get(IntptrTy, AllocaRedzoneMask);
2953 
2954  // Since we need to extend alloca with additional memory to locate
2955  // redzones, and OldSize is number of allocated blocks with
2956  // ElementSize size, get allocated memory size in bytes by
2957  // OldSize * ElementSize.
2958  const unsigned ElementSize =
2960  Value *OldSize =
2961  IRB.CreateMul(IRB.CreateIntCast(AI->getArraySize(), IntptrTy, false),
2962  ConstantInt::get(IntptrTy, ElementSize));
2963 
2964  // PartialSize = OldSize % 32
2965  Value *PartialSize = IRB.CreateAnd(OldSize, AllocaRzMask);
2966 
2967  // Misalign = kAllocaRzSize - PartialSize;
2968  Value *Misalign = IRB.CreateSub(AllocaRzSize, PartialSize);
2969 
2970  // PartialPadding = Misalign != kAllocaRzSize ? Misalign : 0;
2971  Value *Cond = IRB.CreateICmpNE(Misalign, AllocaRzSize);
2972  Value *PartialPadding = IRB.CreateSelect(Cond, Misalign, Zero);
2973 
2974  // AdditionalChunkSize = Align + PartialPadding + kAllocaRzSize
2975  // Align is added to locate left redzone, PartialPadding for possible
2976  // partial redzone and kAllocaRzSize for right redzone respectively.
2977  Value *AdditionalChunkSize = IRB.CreateAdd(
2978  ConstantInt::get(IntptrTy, Align + kAllocaRzSize), PartialPadding);
2979 
2980  Value *NewSize = IRB.CreateAdd(OldSize, AdditionalChunkSize);
2981 
2982  // Insert new alloca with new NewSize and Align params.
2983  AllocaInst *NewAlloca = IRB.CreateAlloca(IRB.getInt8Ty(), NewSize);
2984  NewAlloca->setAlignment(Align);
2985 
2986  // NewAddress = Address + Align
2987  Value *NewAddress = IRB.CreateAdd(IRB.CreatePtrToInt(NewAlloca, IntptrTy),
2988  ConstantInt::get(IntptrTy, Align));
2989 
2990  // Insert __asan_alloca_poison call for new created alloca.
2991  IRB.CreateCall(AsanAllocaPoisonFunc, {NewAddress, OldSize});
2992 
2993  // Store the last alloca's address to DynamicAllocaLayout. We'll need this
2994  // for unpoisoning stuff.
2995  IRB.CreateStore(IRB.CreatePtrToInt(NewAlloca, IntptrTy), DynamicAllocaLayout);
2996 
2997  Value *NewAddressPtr = IRB.CreateIntToPtr(NewAddress, AI->getType());
2998 
2999  // Replace all uses of AddessReturnedByAlloca with NewAddressPtr.
3000  AI->replaceAllUsesWith(NewAddressPtr);
3001 
3002  // We are done. Erase old alloca from parent.
3003  AI->eraseFromParent();
3004 }
3005 
3006 // isSafeAccess returns true if Addr is always inbounds with respect to its
3007 // base object. For example, it is a field access or an array access with
3008 // constant inbounds index.
3009 bool AddressSanitizer::isSafeAccess(ObjectSizeOffsetVisitor &ObjSizeVis,
3010  Value *Addr, uint64_t TypeSize) const {
3011  SizeOffsetType SizeOffset = ObjSizeVis.compute(Addr);
3012  if (!ObjSizeVis.bothKnown(SizeOffset)) return false;
3013  uint64_t Size = SizeOffset.first.getZExtValue();
3014  int64_t Offset = SizeOffset.second.getSExtValue();
3015  // Three checks are required to ensure safety:
3016  // . Offset >= 0 (since the offset is given from the base ptr)
3017  // . Size >= Offset (unsigned)
3018  // . Size - Offset >= NeededSize (unsigned)
3019  return Offset >= 0 && Size >= uint64_t(Offset) &&
3020  Size - uint64_t(Offset) >= TypeSize / 8;
3021 }
void setVisibility(VisibilityTypes V)
Definition: GlobalValue.h:226
static cl::opt< std::string > ClDebugFunc("asan-debug-func", cl::Hidden, cl::desc("Debug func"))
static bool isValueValidForType(Type *Ty, uint64_t V)
This static method returns true if the type Ty is big enough to represent the value V...
Definition: Constants.cpp:1172
uint64_t CallInst * C
void appendToCompilerUsed(Module &M, ArrayRef< GlobalValue *> Values)
Adds global values to the llvm.compiler.used list.
Return a value (possibly void), from a function.
StringRef getSection() const
Get the custom section of this global if it has one.
Definition: GlobalObject.h:90
SymbolTableList< Instruction >::iterator eraseFromParent()
This method unlinks &#39;this&#39; from the containing basic block and deletes it.
Definition: Instruction.cpp:69
static const char *const kAsanSetShadowPrefix
unsigned getAlignment() const
Definition: GlobalObject.h:59
static const uint64_t kIOSShadowOffset32
static cl::opt< bool > ClStack("asan-stack", cl::desc("Handle stack memory"), cl::Hidden, cl::init(true))
A parsed version of the target data layout string in and methods for querying it. ...
Definition: DataLayout.h:109
bool replaceDbgDeclareForAlloca(AllocaInst *AI, Value *NewAllocaAddress, DIBuilder &Builder, bool Deref, int Offset=0)
Replaces llvm.dbg.declare instruction when the alloca it describes is replaced with a new value...
Definition: Local.cpp:1284
uint64_t getTypeStoreSizeInBits(Type *Ty) const
Returns the maximum number of bits that may be overwritten by storing the specified type; always a mu...
Definition: DataLayout.h:396
const std::string & getTargetTriple() const
Get the target triple which is a string describing the target host.
Definition: Module.h:233
ThreadLocalMode getThreadLocalMode() const
Definition: GlobalValue.h:241
void ReplaceInstWithInst(BasicBlock::InstListType &BIL, BasicBlock::iterator &BI, Instruction *I)
Replace the instruction specified by BI with the instruction specified by I.
Function * declareSanitizerInitFunction(Module &M, StringRef InitName, ArrayRef< Type *> InitArgTypes)
static Constant * getString(LLVMContext &Context, StringRef Initializer, bool AddNull=true)
This method constructs a CDS and initializes it with a text string.
Definition: Constants.cpp:2451
void appendToGlobalDtors(Module &M, Function *F, int Priority, Constant *Data=nullptr)
Same as appendToGlobalCtors(), but for global dtors.
Definition: ModuleUtils.cpp:88
bool hasLocalLinkage() const
Definition: GlobalValue.h:416
static const uint64_t kFreeBSD_ShadowOffset64
static cl::opt< bool > ClInitializers("asan-initialization-order", cl::desc("Handle C++ initializer order"), cl::Hidden, cl::init(true))
DILocation * get() const
Get the underlying DILocation.
Definition: DebugLoc.cpp:22
void addIncoming(Value *V, BasicBlock *BB)
Add an incoming value to the end of the PHI list.
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
static bool GlobalWasGeneratedByCompiler(GlobalVariable *G)
Check if G has been created by a trusted compiler pass.
GCNRegPressure max(const GCNRegPressure &P1, const GCNRegPressure &P2)
void SplitBlockAndInsertIfThenElse(Value *Cond, Instruction *SplitBefore, TerminatorInst **ThenTerm, TerminatorInst **ElseTerm, MDNode *BranchWeights=nullptr)
SplitBlockAndInsertIfThenElse is similar to SplitBlockAndInsertIfThen, but also creates the ElseBlock...
This class represents an incoming formal argument to a Function.
Definition: Argument.h:30
LLVM_NODISCARD std::string str() const
str - Get the contents as an std::string.
Definition: StringRef.h:228
AllocaInst * CreateAlloca(Type *Ty, unsigned AddrSpace, Value *ArraySize=nullptr, const Twine &Name="")
Definition: IRBuilder.h:1152
Base class for instruction visitors.
Definition: InstVisitor.h:81
static cl::opt< int > ClMappingScale("asan-mapping-scale", cl::desc("scale of asan shadow mapping"), cl::Hidden, cl::init(0))
Function * checkSanitizerInterfaceFunction(Constant *FuncOrBitcast)
Value * CreateICmpNE(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1549
NodeTy * getNextNode()
Get the next node, or nullptr for the list tail.
Definition: ilist_node.h:289
const Constant * getInitializer() const
getInitializer - Return the initializer for this global variable.
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
bool isMacOSX() const
isMacOSX - Is this a Mac OS X triple.
Definition: Triple.h:440
Constant * getOrInsertFunction(StringRef Name, FunctionType *T, AttributeList AttributeList)
Look up the specified function in the module symbol table.
Definition: Module.cpp:142
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:63
static Constant * getGetElementPtr(Type *Ty, Constant *C, ArrayRef< Constant *> IdxList, bool InBounds=false, Optional< unsigned > InRangeIndex=None, Type *OnlyIfReducedTy=nullptr)
Getelementptr form.
Definition: Constants.h:1115
bool isSized(SmallPtrSetImpl< Type *> *Visited=nullptr) const
Return true if it makes sense to take the size of this type.
Definition: Type.h:262
BasicBlock * getSuccessor(unsigned idx) const
Return the specified successor.
LLVM_ATTRIBUTE_ALWAYS_INLINE size_type size() const
Definition: SmallVector.h:136
void setAlignment(unsigned Align)
bool isOSBinFormatELF() const
Tests whether the OS uses the ELF binary format.
Definition: Triple.h:580
an instruction that atomically checks whether a specified value is in a memory location, and, if it is, stores a new value there.
Definition: Instructions.h:514
Available for inspection, not emission.
Definition: GlobalValue.h:50
static const char *const kAsanUnregisterElfGlobalsName
static const uintptr_t kCurrentStackFrameMagic
This class represents a function call, abstracting a target machine&#39;s calling convention.
static cl::opt< bool > ClUseAfterReturn("asan-use-after-return", cl::desc("Check stack-use-after-return"), cl::Hidden, cl::init(true))
static PointerType * get(Type *ElementType, unsigned AddressSpace)
This constructs a pointer to an object of the specified type in a numbered address space...
Definition: Type.cpp:617
static bool isInterestingPointerComparisonOrSubtraction(Instruction *I)
static const char *const kODRGenPrefix
bool isSwiftError() const
Return true if this alloca is used as a swifterror argument to a call.
Definition: Instructions.h:132
bool isWatchOS() const
Is this an Apple watchOS triple.
Definition: Triple.h:459
Like Internal, but omit from symbol table.
Definition: GlobalValue.h:57
bool RoundToAlign
Whether to round the result up to the alignment of allocas, byval arguments, and global variables...
Externally visible function.
Definition: GlobalValue.h:49
static cl::opt< bool > ClForceDynamicShadow("asan-force-dynamic-shadow", cl::desc("Load shadow address into a local variable for each function"), cl::Hidden, cl::init(false))
bool hasFnAttribute(Attribute::AttrKind Kind) const
Return true if the function has the attribute.
Definition: Function.h:262
static cl::opt< int > ClDebug("asan-debug", cl::desc("debug"), cl::Hidden, cl::init(0))
static cl::opt< bool > ClRecover("asan-recover", cl::desc("Enable recovery mode (continue-after-error)."), cl::Hidden, cl::init(false))
GlobalVariable * getGlobalVariable(StringRef Name) const
Look up the specified global variable in the module symbol table.
Definition: Module.h:368
INITIALIZE_PASS_BEGIN(AddressSanitizer, "asan", "AddressSanitizer: detects use-after-free and out-of-bounds bugs.", false, false) INITIALIZE_PASS_END(AddressSanitizer
unsigned getPointerSizeInBits(unsigned AS=0) const
Layout pointer size, in bits FIXME: The defaults need to be removed once all of the backends/clients ...
Definition: DataLayout.h:346
STATISTIC(NumFunctions, "Total number of functions")
SmallString< 64 > ComputeASanStackFrameDescription(const SmallVectorImpl< ASanStackVariableDescription > &Vars)
A debug info location.
Definition: DebugLoc.h:34
Metadata node.
Definition: Metadata.h:862
StringRef getName() const
Get a short "name" for the module.
Definition: Module.h:220
static cl::opt< bool > ClUseAfterScope("asan-use-after-scope", cl::desc("Check stack-use-after-scope"), cl::Hidden, cl::init(false))
F(f)
static CallInst * Create(Value *Func, ArrayRef< Value *> Args, ArrayRef< OperandBundleDef > Bundles=None, const Twine &NameStr="", Instruction *InsertBefore=nullptr)
const MDOperand & getOperand(unsigned I) const
Definition: Metadata.h:1067
unsigned getPointerAddressSpace() const
Get the address space of this pointer or pointer vector type.
Definition: DerivedTypes.h:503
bool isOSFuchsia() const
Definition: Triple.h:484
An instruction for reading from memory.
Definition: Instructions.h:164
an instruction that atomically reads a memory location, combines it with another value, and then stores the result back.
Definition: Instructions.h:677
void reserve(size_type N)
Definition: SmallVector.h:380
void setAlignment(unsigned Align)
Definition: Globals.cpp:110
static GlobalVariable * createPrivateGlobalForString(Module &M, StringRef Str, bool AllowMerging)
static cl::opt< unsigned long long > ClMappingOffset("asan-mapping-offset", cl::desc("offset of asan shadow mapping [EXPERIMENTAL]"), cl::Hidden, cl::init(0))
Tentative definitions.
Definition: GlobalValue.h:59
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE const char * data() const
data - Get a pointer to the start of the string (which may not be null terminated).
Definition: StringRef.h:128
static Constant * get(ArrayType *T, ArrayRef< Constant *> V)
Definition: Constants.cpp:888
bool isAllocaPromotable(const AllocaInst *AI)
Return true if this alloca is legal for promotion.
static Constant * getNullValue(Type *Ty)
Constructor to create a &#39;0&#39; constant of arbitrary type.
Definition: Constants.cpp:207
StoreInst * CreateAlignedStore(Value *Val, Value *Ptr, unsigned Align, bool isVolatile=false)
Definition: IRBuilder.h:1199
iterator begin()
Instruction iterator methods.
Definition: BasicBlock.h:252
static void doInstrumentAddress(AddressSanitizer *Pass, Instruction *I, Instruction *InsertBefore, Value *Addr, unsigned Alignment, unsigned Granularity, uint32_t TypeSize, bool IsWrite, Value *SizeArgument, bool UseCalls, uint32_t Exp)
static ReturnInst * Create(LLVMContext &C, Value *retVal=nullptr, Instruction *InsertBefore=nullptr)
IntegerType * getInt32Ty()
Fetch the type representing a 32-bit integer.
Definition: IRBuilder.h:348
static const uint64_t kDefaultShadowScale
static const char *const kAsanShadowMemoryDynamicAddress
static const int kAsanStackUseAfterReturnMagic
AnalysisUsage & addRequired()
#define INITIALIZE_PASS_DEPENDENCY(depName)
Definition: PassSupport.h:51
A tuple of MDNodes.
Definition: Metadata.h:1323
bool doesNotReturn() const
Determine if the call cannot return.
Definition: CallSite.h:479
Type * getPointerElementType() const
Definition: Type.h:373
const DataLayout & getDataLayout() const
Get the data layout for the module&#39;s target platform.
Definition: Module.cpp:361
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:81
unsigned getAlignment() const
Return the alignment of the memory that is being allocated by the instruction.
Definition: Instructions.h:109
unsigned getNumArgOperands() const
Return the number of call arguments.
IntegerType * getInt64Ty()
Fetch the type representing a 64-bit integer.
Definition: IRBuilder.h:353
This is the base class for all instructions that perform data casts.
Definition: InstrTypes.h:560
PointerType * getType() const
Overload to return most specific pointer type.
Definition: Instructions.h:97
Class to represent struct types.
Definition: DerivedTypes.h:201
LLVMContext & getContext() const
Get the global data context.
Definition: Module.h:237
static const uint64_t kLinuxKasan_ShadowOffset64
A Use represents the edge between a Value definition and its users.
Definition: Use.h:56
PointerType * getPointerTo(unsigned AddrSpace=0) const
Return a pointer to the current type.
Definition: Type.cpp:639
bool isConstant() const
If the value is a global constant, its value is immutable throughout the runtime execution of the pro...
This provides a uniform API for creating instructions and inserting them into a basic block: either a...
Definition: IRBuilder.h:664
InstrTy * getInstruction() const
Definition: CallSite.h:92
static const char *const kAsanAllocasUnpoison
Value * CreateAdd(Value *LHS, Value *RHS, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:889
void setName(const Twine &Name)
Change the name of the value.
Definition: Value.cpp:284
static const char *const kAsanModuleCtorName
static const uint64_t kIOSSimShadowOffset64
Definition: regcomp.c:64
static StructType * get(LLVMContext &Context, ArrayRef< Type *> Elements, bool isPacked=false)
This static method is the primary way to create a literal StructType.
Definition: Type.cpp:336
Type * getVoidTy()
Fetch the type representing void.
Definition: IRBuilder.h:381
StoreInst * CreateStore(Value *Val, Value *Ptr, bool isVolatile=false)
Definition: IRBuilder.h:1176
Value * CreateIntToPtr(Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1440
bool isOne() const
This is just a convenience method to make client code smaller for a common case.
Definition: Constants.h:201
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool startswith(StringRef Prefix) const
Check if this string starts with the given Prefix.
Definition: StringRef.h:267
static const char *const kAsanPoisonStackMemoryName
static const uint64_t kSmallX86_64ShadowOffset
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:245
void clear()
Definition: SmallSet.h:119
SmallVector< uint8_t, 64 > GetShadowBytesAfterScope(const SmallVectorImpl< ASanStackVariableDescription > &Vars, const ASanStackFrameLayout &Layout)
ConstantDataSequential - A vector or array constant whose element type is a simple 1/2/4/8-byte integ...
Definition: Constants.h:565
static const char *const kSanCovGenPrefix
bool empty() const
Definition: Module.h:581
bool isSwiftError() const
Return true if this value is a swifterror value.
Definition: Value.cpp:718
ArchType getArch() const
getArch - Get the parsed architecture type of this triple.
Definition: Triple.h:283
Class to represent array types.
Definition: DerivedTypes.h:369
bool isUsedWithInAlloca() const
Return true if this alloca is used as an inalloca argument to a call.
Definition: Instructions.h:121
static const int kMaxAsanStackMallocSizeClass
static const uint64_t kIOSSimShadowOffset32
static cl::opt< bool > ClOptSameTemp("asan-opt-same-temp", cl::desc("Instrument the same temp just once"), cl::Hidden, cl::init(true))
static cl::opt< bool > ClEnableKasan("asan-kernel", cl::desc("Enable KernelAddressSanitizer instrumentation"), cl::Hidden, cl::init(false))
static const uint64_t kAsanCtorAndDtorPriority
void setComdat(Comdat *C)
Definition: GlobalObject.h:103
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool empty() const
empty - Check if the string is empty.
Definition: StringRef.h:133
NamedMDNode * getNamedMetadata(const Twine &Name) const
Return the first NamedMDNode in the module with the specified name.
Definition: Module.cpp:242
static cl::opt< bool > ClOpt("asan-opt", cl::desc("Optimize instrumentation"), cl::Hidden, cl::init(true))
MDNode * getMetadata(unsigned KindID) const
Get the metadata of given kind attached to this Instruction.
Definition: Instruction.h:194
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: APInt.h:33
const APInt & getValue() const
Return the constant as an APInt value reference.
Definition: Constants.h:138
bool isLittleEndian() const
Layout endianness...
Definition: DataLayout.h:216
static const uint64_t kWindowsShadowOffset64
Value * CreateSub(Value *LHS, Value *RHS, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:911
bool isiOS() const
Is this an iOS triple.
Definition: Triple.h:449
An instruction for storing to memory.
Definition: Instructions.h:306
void SetCurrentDebugLocation(DebugLoc L)
Set location information used by debugging information.
Definition: IRBuilder.h:152
bool isMinusOne() const
This function will return true iff every bit in this constant is set to true.
Definition: Constants.h:209
LinkageTypes getLinkage() const
Definition: GlobalValue.h:430
void replaceAllUsesWith(Value *V)
Change all uses of this to point to a new Value.
Definition: Value.cpp:428
bool isOSNetBSD() const
Definition: Triple.h:472
Debug location.
void takeName(Value *V)
Transfer the name from V to this value.
Definition: Value.cpp:290
iterator begin()
Definition: Function.h:588
static cl::opt< bool > ClAlwaysSlowPath("asan-always-slow-path", cl::desc("use instrumentation with slow path for all accesses"), cl::Hidden, cl::init(false))
Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree...
Definition: Dominators.h:140
iterator_range< op_iterator > operands()
Definition: Metadata.h:1415
Function * getDeclaration(Module *M, ID id, ArrayRef< Type *> Tys=None)
Create or insert an LLVM Function declaration for an intrinsic, and return it.
Definition: Function.cpp:975
void SetInsertPoint(BasicBlock *TheBB)
This specifies that created instructions should be appended to the end of the specified block...
Definition: IRBuilder.h:128
static const uint64_t kDefaultShadowOffset32
Value * getOperand(unsigned i) const
Definition: User.h:154
ConstantInt * getIntN(unsigned N, uint64_t C)
Get a constant N-bit value, zero extended or truncated from a 64-bit value.
Definition: IRBuilder.h:319
Class to represent pointers.
Definition: DerivedTypes.h:467
static void instrumentMaskedLoadOrStore(AddressSanitizer *Pass, const DataLayout &DL, Type *IntptrTy, Value *Mask, Instruction *I, Value *Addr, unsigned Alignment, unsigned Granularity, uint32_t TypeSize, bool IsWrite, Value *SizeArgument, bool UseCalls, uint32_t Exp)
Value * CreateOr(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1079
Constant * getAggregateElement(unsigned Elt) const
For aggregates (struct/array/vector) return the constant that corresponds to the specified element if...
Definition: Constants.cpp:277
Type * getScalarType() const
If this is a vector type, return the element type, otherwise return &#39;this&#39;.
Definition: Type.h:301
static cl::opt< bool > ClInstrumentWrites("asan-instrument-writes", cl::desc("instrument write instructions"), cl::Hidden, cl::init(true))
bool isOSWindows() const
Tests whether the OS is Windows.
Definition: Triple.h:554
ExternalWeak linkage description.
Definition: GlobalValue.h:58
const BasicBlock & getEntryBlock() const
Definition: Function.h:572
an instruction for type-safe pointer arithmetic to access elements of arrays and structs ...
Definition: Instructions.h:837
LoadInst * CreateLoad(Value *Ptr, const char *Name)
Definition: IRBuilder.h:1164
static const size_t kNumberOfAccessSizes
static MDTuple * get(LLVMContext &Context, ArrayRef< Metadata *> MDs)
Definition: Metadata.h:1164
static const char *const kAsanGlobalsRegisteredFlagName
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:406
No other Module may specify this COMDAT.
Definition: Comdat.h:35
static const char *const kAsanPtrCmp
uint64_t getZExtValue() const
Return the constant as a 64-bit unsigned integer value after it has been zero extended as appropriate...
Definition: Constants.h:149
static std::string ParseSectionSpecifier(StringRef Spec, StringRef &Segment, StringRef &Section, unsigned &TAA, bool &TAAParsed, unsigned &StubSize)
Parse the section specifier indicated by "Spec".
Subclasses of this class are all able to terminate a basic block.
Definition: InstrTypes.h:54
* if(!EatIfPresent(lltok::kw_thread_local)) return false
ParseOptionalThreadLocal := /*empty.
const_iterator getFirstInsertionPt() const
Returns an iterator to the first instruction in this block that is suitable for inserting a non-PHI i...
Definition: BasicBlock.cpp:200
void setDebugLoc(DebugLoc Loc)
Set the debug location information for this instruction.
Definition: Instruction.h:281
DLLStorageClassTypes getDLLStorageClass() const
Definition: GlobalValue.h:245
std::size_t countTrailingZeros(T Val, ZeroBehavior ZB=ZB_Width)
Count number of 0&#39;s from the least significant bit to the most stopping at the first 1...
Definition: MathExtras.h:112
VisibilityTypes getVisibility() const
Definition: GlobalValue.h:220
constexpr bool isPowerOf2_32(uint32_t Value)
Return true if the argument is a power of two > 0.
Definition: MathExtras.h:421
bool hasName() const
Definition: Value.h:251
LLVM Basic Block Representation.
Definition: BasicBlock.h:59
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
std::pair< Function *, Function * > createSanitizerCtorAndInitFunctions(Module &M, StringRef CtorName, StringRef InitName, ArrayRef< Type *> InitArgTypes, ArrayRef< Value *> InitArgs, StringRef VersionCheckName=StringRef())
Creates sanitizer constructor function, and calls sanitizer&#39;s init function from it.
bool isOSBinFormatCOFF() const
Tests whether the OS uses the COFF binary format.
Definition: Triple.h:585
This is an important class for using LLVM in a threaded context.
Definition: LLVMContext.h:69
DISubprogram * getSubprogram() const
Get the attached subprogram.
Definition: Metadata.cpp:1498
Constant * getOrInsertGlobal(StringRef Name, Type *Ty)
Look up the specified global in the module symbol table.
Definition: Module.cpp:202
Conditional or Unconditional Branch instruction.
static const size_t kMinStackMallocSize
size_t size() const
size - Get the array size.
Definition: ArrayRef.h:149
This function has undefined behavior.
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
This is an important base class in LLVM.
Definition: Constant.h:42
Resume the propagation of an exception.
static const char *const kAsanInitName
static const char *const kAsanStackFreeNameTemplate
SmallSet - This maintains a set of unique values, optimizing for the case when the set is small (less...
Definition: SmallSet.h:36
Value * CreateSelect(Value *C, Value *True, Value *False, const Twine &Name="", Instruction *MDFrom=nullptr)
Definition: IRBuilder.h:1689
bool isPointerTy() const
True if this is an instance of PointerType.
Definition: Type.h:221
static const uint64_t kMIPS32_ShadowOffset32
const Instruction & front() const
Definition: BasicBlock.h:264
static const char *const kAsanOptionDetectUseAfterReturn
static const uint64_t kFreeBSD_ShadowOffset32
static const uint64_t kAArch64_ShadowOffset64
static cl::opt< bool > ClInstrumentReads("asan-instrument-reads", cl::desc("instrument read instructions"), cl::Hidden, cl::init(true))
Represent the analysis usage information of a pass.
static Type * getVoidTy(LLVMContext &C)
Definition: Type.cpp:161
bool isPS4CPU() const
Tests whether the target is the PS4 CPU.
Definition: Triple.h:600
This instruction compares its operands according to the predicate given to the constructor.
static const unsigned End
Value * CreateICmpSGE(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1567
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:285
static FunctionType * get(Type *Result, ArrayRef< Type *> Params, bool isVarArg)
This static method is the primary way of constructing a FunctionType.
Definition: Type.cpp:297
static Constant * get(StructType *T, ArrayRef< Constant *> V)
Definition: Constants.cpp:949
op_range operands()
Definition: User.h:222
static BasicBlock * Create(LLVMContext &Context, const Twine &Name="", Function *Parent=nullptr, BasicBlock *InsertBefore=nullptr)
Creates a new BasicBlock.
Definition: BasicBlock.h:101
Value * CreateICmpEQ(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1546
ASanStackFrameLayout ComputeASanStackFrameLayout(SmallVectorImpl< ASanStackVariableDescription > &Vars, size_t Granularity, size_t MinHeaderSize)
static cl::opt< bool > ClOptGlobals("asan-opt-globals", cl::desc("Don't instrument scalar globals"), cl::Hidden, cl::init(true))
static cl::opt< bool > ClUseGlobalsGC("asan-globals-live-support", cl::desc("Use linker features to support dead " "code stripping of globals"), cl::Hidden, cl::init(true))
std::pair< NoneType, bool > insert(const T &V)
insert - Insert an element into the set if it isn&#39;t already there.
Definition: SmallSet.h:81
static const uintptr_t kRetiredStackFrameMagic
Value * CreateExtractElement(Value *Vec, Value *Idx, const Twine &Name="")
Definition: IRBuilder.h:1709
static cl::opt< bool > ClUsePrivateAliasForGlobals("asan-use-private-alias", cl::desc("Use private aliases for global" " variables"), cl::Hidden, cl::init(false))
static const char *const kAsanGenPrefix
bool isOSBinFormatMachO() const
Tests whether the environment is MachO.
Definition: Triple.h:590
std::string getUniqueModuleId(Module *M)
Produce a unique identifier for this module by taking the MD5 sum of the names of the module&#39;s strong...
static const char *const kAsanPtrSub
static cl::opt< int > ClMaxInsnsToInstrumentPerBB("asan-max-ins-per-bb", cl::init(10000), cl::desc("maximal number of instructions to instrument in any given BB"), cl::Hidden)
S_CSTRING_LITERALS - Section with literal C strings.
Definition: MachO.h:124
Comdat * getOrInsertComdat(StringRef Name)
Return the Comdat in the module with the specified name.
Definition: Module.cpp:467
const Value * stripPointerCasts() const
Strip off pointer casts, all-zero GEPs, and aliases.
Definition: Value.cpp:527
static std::string itostr(int64_t X)
Definition: StringExtras.h:175
static cl::opt< bool > ClGlobals("asan-globals", cl::desc("Handle global objects"), cl::Hidden, cl::init(true))
static cl::opt< uint32_t > ClMaxInlinePoisoningSize("asan-max-inline-poisoning-size", cl::desc("Inline shadow poisoning for blocks up to the given size in bytes."), cl::Hidden, cl::init(64))
const Value * getArraySize() const
Get the number of elements allocated.
Definition: Instructions.h:93
std::pair< APInt, APInt > SizeOffsetType
static wasm::ValType getType(const TargetRegisterClass *RC)
PointerType * getInt8PtrTy(unsigned AddrSpace=0)
Fetch the type representing a pointer to an 8-bit integer value.
Definition: IRBuilder.h:386
const std::string & getModuleIdentifier() const
Get the module identifier which is, essentially, the name of the module.
Definition: Module.h:208
MDNode * createBranchWeights(uint32_t TrueWeight, uint32_t FalseWeight)
Return metadata containing two branch weights.
Definition: MDBuilder.cpp:37
static const uint64_t kWindowsShadowOffset32
Value * GetUnderlyingObject(Value *V, const DataLayout &DL, unsigned MaxLookup=6)
This method strips off any GEP address adjustments and pointer casts from the specified value...
INITIALIZE_PASS_END(RegBankSelect, DEBUG_TYPE, "Assign register bank of generic virtual registers", false, false) RegBankSelect
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
void initializeAddressSanitizerPass(PassRegistry &)
Value * CreateMul(Value *LHS, Value *RHS, const Twine &Name="", bool HasNUW=false, bool HasNSW=false)
Definition: IRBuilder.h:933
static cl::opt< bool > ClWithComdat("asan-with-comdat", cl::desc("Place ASan constructors in comdat sections"), cl::Hidden, cl::init(true))
Type * getAllocatedType() const
Return the type that is being allocated by the instruction.
Definition: Instructions.h:102
Triple - Helper class for working with autoconf configuration names.
Definition: Triple.h:44
static const char *const kAsanRegisterGlobalsName
Intrinsic::ID getIntrinsicID() const
Return the intrinsic ID of this intrinsic.
Definition: IntrinsicInst.h:51
PHINode * CreatePHI(Type *Ty, unsigned NumReservedValues, const Twine &Name="")
Definition: IRBuilder.h:1654
Value * CreateGEP(Value *Ptr, ArrayRef< Value *> IdxList, const Twine &Name="")
Definition: IRBuilder.h:1223
static Constant * getPointerCast(Constant *C, Type *Ty)
Create a BitCast, AddrSpaceCast, or a PtrToInt cast constant expression.
Definition: Constants.cpp:1492
static const uint64_t kDynamicShadowSentinel
static IntegerType * get(LLVMContext &C, unsigned NumBits)
This static method is the primary way of constructing an IntegerType.
Definition: Type.cpp:240
static cl::opt< int > ClDebugMax("asan-debug-max", cl::desc("Debug max inst"), cl::Hidden, cl::init(-1))
print lazy value Lazy Value Info Printer Pass
This is the common base class for memset/memcpy/memmove.
uint64_t getLimitedValue(uint64_t Limit=~0ULL) const
getLimitedValue - If the value is smaller than the specified limit, return it, otherwise return the l...
Definition: Constants.h:251
This is the shared class of boolean and integer constants.
Definition: Constants.h:84
void setSelectionKind(SelectionKind Val)
Definition: Comdat.h:43
static const char *const kAsanStackMallocNameTemplate
static const char *const kAsanUnpoisonStackMemoryName
Evaluate the size and offset of an object pointed to by a Value* statically.
Value * CreateIntCast(Value *V, Type *DestTy, bool isSigned, const Twine &Name="")
Definition: IRBuilder.h:1507
static ValueAsMetadata * get(Value *V)
Definition: Metadata.cpp:341
bool hasSection() const
Check if this global has a custom object file section.
Definition: GlobalObject.h:82
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:864
static size_t TypeSizeToSizeIndex(uint32_t TypeSize)
Module.h This file contains the declarations for the Module class.
Provides information about what library functions are available for the current target.
unsigned getABITypeAlignment(Type *Ty) const
Returns the minimum ABI-required alignment for the specified type.
Definition: DataLayout.cpp:682
const DataFlowGraph & G
Definition: RDFGraph.cpp:211
bool isOSLinux() const
Tests whether the OS is Linux.
Definition: Triple.h:564
TerminatorInst * SplitBlockAndInsertIfThen(Value *Cond, Instruction *SplitBefore, bool Unreachable, MDNode *BranchWeights=nullptr, DominatorTree *DT=nullptr, LoopInfo *LI=nullptr)
Split the containing block at the specified instruction - everything before SplitBefore stays in the ...
static const uint64_t kDefaultShadowOffset64
ConstantInt * getInt32(uint32_t C)
Get a constant 32-bit value.
Definition: IRBuilder.h:308
static IntegerType * getIntNTy(LLVMContext &C, unsigned N)
Definition: Type.cpp:180
static cl::opt< int > ClDebugStack("asan-debug-stack", cl::desc("debug stack"), cl::Hidden, cl::init(0))
static GCRegistry::Add< StatepointGC > D("statepoint-example", "an example strategy for statepoint")
static Constant * get(Type *Ty, uint64_t V, bool isSigned=false)
If Ty is a vector type, return a Constant with a splat of the given value.
Definition: Constants.cpp:560
static BranchInst * Create(BasicBlock *IfTrue, Instruction *InsertBefore=nullptr)
void appendToGlobalCtors(Module &M, Function *F, int Priority, Constant *Data=nullptr)
Append F to the list of global ctors of module M with the given Priority.
Definition: ModuleUtils.cpp:84
static cl::opt< bool > ClInvalidPointerPairs("asan-detect-invalid-pointer-pair", cl::desc("Instrument <, <=, >, >=, - with pointer operands"), cl::Hidden, cl::init(false))
static bool isPointerOperand(Value *V)
static cl::opt< int > ClInstrumentationWithCallsThreshold("asan-instrumentation-with-call-threshold", cl::desc("If the function being instrumented contains more than " "this number of memory accesses, use callbacks instead of " "inline checks (-1 means never use callbacks)."), cl::Hidden, cl::init(7000))
bool isOSFreeBSD() const
Definition: Triple.h:480
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
Function * getFunction(StringRef Name) const
Look up the specified function in the module symbol table.
Definition: Module.cpp:172
SizeOffsetType compute(Value *V)
const Module * getModule() const
Return the module owning the function this instruction belongs to or nullptr it the function does not...
Definition: Instruction.cpp:57
ConstantArray - Constant Array Declarations.
Definition: Constants.h:405
static StringRef dropLLVMManglingEscape(StringRef Name)
If the given string begins with the GlobalValue name mangling escape character &#39;\1&#39;, drop it.
Definition: GlobalValue.h:451
static const uint64_t kSystemZ_ShadowOffset64
static GlobalVariable * createPrivateGlobalForSourceLoc(Module &M, LocationMetadata MD)
Create a global describing a source location.
LinkageTypes
An enumeration for the kinds of linkage for global values.
Definition: GlobalValue.h:48
IntegerType * getInt8Ty()
Fetch the type representing an 8-bit integer.
Definition: IRBuilder.h:338
Value * CreatePointerCast(Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1484
bool hasComdat() const
Definition: GlobalObject.h:100
void setMetadata(unsigned KindID, MDNode *MD)
Set a particular kind of metadata attachment.
Definition: Metadata.cpp:1421
constexpr char Size[]
Key for Kernel::Arg::Metadata::mSize.
amdgpu Simplify well known AMD library false Value Value * Arg
static cl::opt< bool > ClSkipPromotableAllocas("asan-skip-promotable-allocas", cl::desc("Do not instrument promotable allocas"), cl::Hidden, cl::init(true))
const Comdat * getComdat() const
Definition: GlobalObject.h:101
uint64_t getTypeAllocSize(Type *Ty) const
Returns the offset in bytes between successive objects of the specified type, including alignment pad...
Definition: DataLayout.h:405
static cl::opt< int > ClDebugMin("asan-debug-min", cl::desc("Debug min inst"), cl::Hidden, cl::init(-1))
static cl::opt< std::string > ClMemoryAccessCallbackPrefix("asan-memory-access-callback-prefix", cl::desc("Prefix for memory access callbacks"), cl::Hidden, cl::init("__asan_"))
const DebugLoc & getDebugLoc() const
Return the debug location for this node as a DebugLoc.
Definition: Instruction.h:284
bool isInlineAsm() const
Check if this call is an inline asm statement.
static const uint64_t kMIPS64_ShadowOffset64
CallInst * CreateMemCpy(Value *Dst, Value *Src, uint64_t Size, unsigned Align, bool isVolatile=false, MDNode *TBAATag=nullptr, MDNode *TBAAStructTag=nullptr, MDNode *ScopeTag=nullptr, MDNode *NoAliasTag=nullptr)
Create and insert a memcpy between the specified pointers.
Definition: IRBuilder.h:423
void setUnnamedAddr(UnnamedAddr Val)
Definition: GlobalValue.h:203
static const size_t npos
Definition: StringRef.h:51
static IntegerType * getInt32Ty(LLVMContext &C)
Definition: Type.cpp:176
ObjectFormatType getObjectFormat() const
getFormat - Get the object format for this triple.
Definition: Triple.h:313
static int StackMallocSizeClass(uint64_t LocalStackSize)
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:61
static cl::opt< uint32_t > ClForceExperiment("asan-force-experiment", cl::desc("Force optimization experiment (for testing)"), cl::Hidden, cl::init(0))
static const char *const kAsanRegisterElfGlobalsName
uint64_t getLimitedValue(uint64_t Limit=UINT64_MAX) const
If this value is smaller than the specified limit, return it, otherwise return the limit value...
Definition: APInt.h:475
Value * getArgOperand(unsigned i) const
getArgOperand/setArgOperand - Return/set the i-th call argument.
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:218
void copyAttributesFrom(const GlobalVariable *Src)
copyAttributesFrom - copy all additional attributes (those not needed to create a GlobalVariable) fro...
Definition: Globals.cpp:362
const Function * getParent() const
Return the enclosing method, or null if none.
Definition: BasicBlock.h:108
static cl::opt< bool > ClDynamicAllocaStack("asan-stack-dynamic-alloca", cl::desc("Use dynamic alloca to represent stack variables"), cl::Hidden, cl::init(true))
#define I(x, y, z)
Definition: MD5.cpp:58
#define N
ModulePass class - This class is used to implement unstructured interprocedural optimizations and ana...
Definition: Pass.h:225
constexpr char Align[]
Key for Kernel::Arg::Metadata::mAlign.
static ArrayType * get(Type *ElementType, uint64_t NumElements)
This static method is the primary way to construct an ArrayType.
Definition: Type.cpp:568
LLVM_NODISCARD std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:323
Type * getValueType() const
Definition: GlobalValue.h:262
const BasicBlockListType & getBasicBlockList() const
Get the underlying elements of the Function...
Definition: Function.h:565
static const uint64_t kNetBSD_ShadowOffset64
Rename collisions when linking (static functions).
Definition: GlobalValue.h:56
void maybeMarkSanitizerLibraryCallNoBuiltin(CallInst *CI, const TargetLibraryInfo *TLI)
Given a CallInst, check if it calls a string function known to CodeGen, and mark it with NoBuiltin if...
Definition: Local.cpp:2165
static InlineAsm * get(FunctionType *Ty, StringRef AsmString, StringRef Constraints, bool hasSideEffects, bool isAlignStack=false, AsmDialect asmDialect=AD_ATT)
InlineAsm::get - Return the specified uniqued inline asm string.
Definition: InlineAsm.cpp:43
static const uint64_t kPS4CPU_ShadowOffset64
bool isMacOSXVersionLT(unsigned Major, unsigned Minor=0, unsigned Micro=0) const
isMacOSXVersionLT - Comparison function for checking OS X version compatibility, which handles suppor...
Definition: Triple.h:425
static const char *const kAsanModuleDtorName
Value * CreateAnd(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:1063
Value * CreatePtrToInt(Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:1436
const std::string to_string(const T &Value)
Definition: ScopedPrinter.h:62
static const char *const kAsanUnregisterGlobalsName
iterator_range< df_iterator< T > > depth_first(const T &G)
static const char *const kAsanUnpoisonGlobalsName
iterator_range< op_iterator > arg_operands()
Iteration adapter for range-for loops.
bool isArrayAllocation() const
Return true if there is an allocation size parameter to the allocation instruction that is not 1...
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
const BasicBlock & front() const
Definition: Function.h:595
static bool bothKnown(const SizeOffsetType &SizeOffset)
static const char *const kAsanPoisonGlobalsName
Module * getParent()
Get the module that this global value is contained inside of...
Definition: GlobalValue.h:545
LLVM Value Representation.
Definition: Value.h:73
INITIALIZE_PASS(AddressSanitizerModule, "asan-module", "AddressSanitizer: detects use-after-free and out-of-bounds bugs." "ModulePass", false, false) ModulePass *llvm
static const char *const kAsanVersionCheckName
static const uint64_t kPPC64_ShadowOffset64
static const unsigned kAllocaRzSize
bool hasInitializer() const
Definitions have initializers, declarations don&#39;t.
static cl::opt< bool > ClRedzoneByvalArgs("asan-redzone-byval-args", cl::desc("Create redzones for byval " "arguments (extra copy " "required)"), cl::Hidden, cl::init(true))
static cl::opt< bool > ClInstrumentAtomics("asan-instrument-atomics", cl::desc("instrument atomic instructions (rmw, cmpxchg)"), cl::Hidden, cl::init(true))
static const char *const kAsanUnregisterImageGlobalsName
std::underlying_type< E >::type Mask()
Get a bitmask with 1s in all places up to the high-order bit of E&#39;s largest value.
Definition: BitmaskEnum.h:81
static const Function * getParent(const Value *V)
void moveBefore(Instruction *MovePos)
Unlink this instruction from its current basic block and insert it into the basic block that MovePos ...
Definition: Instruction.cpp:88
bool isAndroid() const
Tests whether the target is Android.
Definition: Triple.h:613
static const char *const kAsanRegisterImageGlobalsName
static Constant * getAnon(ArrayRef< Constant *> V, bool Packed=false)
Return an anonymous struct that has the specified elements.
Definition: Constants.h:460
Value * CreateLShr(Value *LHS, Value *RHS, const Twine &Name="", bool isExact=false)
Definition: IRBuilder.h:1027
#define DEBUG(X)
Definition: Debug.h:118
void addDebugInfo(DIGlobalVariableExpression *GV)
Attach a DIGlobalVariableExpression.
Definition: Metadata.cpp:1511
bool isThreadLocal() const
If the value is "Thread Local", its value isn&#39;t shared by the threads.
Definition: GlobalValue.h:233
FunctionPass * createAddressSanitizerFunctionPass(bool CompileKernel=false, bool Recover=false, bool UseAfterScope=false)
static const char *const kAsanAllocaPoison
static const char *const kAsanHandleNoReturnName
iterator_range< global_iterator > globals()
Definition: Module.h:561
IRTranslator LLVM IR MI
static const size_t kMaxStackMallocSize
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
Various options to control the behavior of getObjectSize.
A single uniqued string.
Definition: Metadata.h:602
bool isOSVersionLT(unsigned Major, unsigned Minor=0, unsigned Micro=0) const
isOSVersionLT - Helper function for doing comparisons against version numbers included in the target ...
Definition: Triple.h:401
static Function * Create(FunctionType *Ty, LinkageTypes Linkage, const Twine &N="", Module *M=nullptr)
Definition: Function.h:136
Legacy analysis pass which computes a DominatorTree.
Definition: Dominators.h:267
static cl::opt< bool > ClOptStack("asan-opt-stack", cl::desc("Don't instrument scalar stack variables"), cl::Hidden, cl::init(false))
bool isStaticAlloca() const
Return true if this alloca is in the entry block of the function and is a constant size...
pgo instr use
bool isOSBinFormatWasm() const
Tests whether the OS uses the Wasm binary format.
Definition: Triple.h:595
static cl::opt< unsigned > ClRealignStack("asan-realign-stack", cl::desc("Realign stack to the value of this flag (power of two)"), cl::Hidden, cl::init(32))
unsigned getNumOperands() const
Return number of MDNode operands.
Definition: Metadata.h:1073
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE size_t find(char C, size_t From=0) const
Search for the first character C in the string.
Definition: StringRef.h:298
ModulePass * createAddressSanitizerModulePass(bool CompileKernel=false, bool Recover=false, bool UseGlobalsGC=true)
Root of the metadata hierarchy.
Definition: Metadata.h:58
static cl::opt< bool > ClInstrumentDynamicAllocas("asan-instrument-dynamic-allocas", cl::desc("instrument dynamic allocas"), cl::Hidden, cl::init(true))
void setSection(StringRef S)
Change the section for this global.
Definition: Globals.cpp:183
#define OP(n)
Definition: regex2.h:70
static GlobalAlias * create(Type *Ty, unsigned AddressSpace, LinkageTypes Linkage, const Twine &Name, Constant *Aliasee, Module *Parent)
If a parent module is specified, the alias is automatically inserted into the end of the specified mo...
Definition: Globals.cpp:399
iterator_range< arg_iterator > args()
Definition: Function.h:621
A wrapper class for inspecting calls to intrinsic functions.
Definition: IntrinsicInst.h:44
const BasicBlock * getParent() const
Definition: Instruction.h:66
an instruction to allocate memory on the stack
Definition: Instructions.h:60
SmallVector< uint8_t, 64 > GetShadowBytes(const SmallVectorImpl< ASanStackVariableDescription > &Vars, const ASanStackFrameLayout &Layout)
static const char *const kAsanReportErrorTemplate
CallInst * CreateCall(Value *Callee, ArrayRef< Value *> Args=None, const Twine &Name="", MDNode *FPMathTag=nullptr)
Definition: IRBuilder.h:1659
size_type count(const T &V) const
count - Return 1 if the element is in the set, 0 otherwise.
Definition: SmallSet.h:65
void resize(size_type N)
Definition: SmallVector.h:355