Bug Summary

File:lib/Analysis/MemorySSA.cpp
Warning:line 1684, column 5
Called C++ object pointer is null

Annotated Source Code

Press '?' to see keyboard shortcuts

clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name MemorySSA.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-eagerly-assume -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-7/lib/clang/7.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-7~svn329677/build-llvm/lib/Analysis -I /build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis -I /build/llvm-toolchain-snapshot-7~svn329677/build-llvm/include -I /build/llvm-toolchain-snapshot-7~svn329677/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/x86_64-linux-gnu/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/x86_64-linux-gnu/c++/7.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../../include/c++/7.3.0/backward -internal-isystem /usr/include/clang/7.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-7/lib/clang/7.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-7~svn329677/build-llvm/lib/Analysis -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-checker optin.performance.Padding -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-04-11-031539-24776-1 -x c++ /build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp

/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp

1//===- MemorySSA.cpp - Memory SSA Builder ---------------------------------===//
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 implements the MemorySSA class.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Analysis/MemorySSA.h"
15#include "llvm/ADT/DenseMap.h"
16#include "llvm/ADT/DenseMapInfo.h"
17#include "llvm/ADT/DenseSet.h"
18#include "llvm/ADT/DepthFirstIterator.h"
19#include "llvm/ADT/Hashing.h"
20#include "llvm/ADT/None.h"
21#include "llvm/ADT/Optional.h"
22#include "llvm/ADT/STLExtras.h"
23#include "llvm/ADT/SmallPtrSet.h"
24#include "llvm/ADT/SmallVector.h"
25#include "llvm/ADT/iterator.h"
26#include "llvm/ADT/iterator_range.h"
27#include "llvm/Analysis/AliasAnalysis.h"
28#include "llvm/Analysis/IteratedDominanceFrontier.h"
29#include "llvm/Analysis/MemoryLocation.h"
30#include "llvm/IR/AssemblyAnnotationWriter.h"
31#include "llvm/IR/BasicBlock.h"
32#include "llvm/IR/CallSite.h"
33#include "llvm/IR/Dominators.h"
34#include "llvm/IR/Function.h"
35#include "llvm/IR/Instruction.h"
36#include "llvm/IR/Instructions.h"
37#include "llvm/IR/IntrinsicInst.h"
38#include "llvm/IR/Intrinsics.h"
39#include "llvm/IR/LLVMContext.h"
40#include "llvm/IR/PassManager.h"
41#include "llvm/IR/Use.h"
42#include "llvm/Pass.h"
43#include "llvm/Support/AtomicOrdering.h"
44#include "llvm/Support/Casting.h"
45#include "llvm/Support/CommandLine.h"
46#include "llvm/Support/Compiler.h"
47#include "llvm/Support/Debug.h"
48#include "llvm/Support/ErrorHandling.h"
49#include "llvm/Support/FormattedStream.h"
50#include "llvm/Support/raw_ostream.h"
51#include <algorithm>
52#include <cassert>
53#include <iterator>
54#include <memory>
55#include <utility>
56
57using namespace llvm;
58
59#define DEBUG_TYPE"memoryssa" "memoryssa"
60
61INITIALIZE_PASS_BEGIN(MemorySSAWrapperPass, "memoryssa", "Memory SSA", false,static void *initializeMemorySSAWrapperPassPassOnce(PassRegistry
&Registry) {
62 true)static void *initializeMemorySSAWrapperPassPassOnce(PassRegistry
&Registry) {
63INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
64INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)initializeAAResultsWrapperPassPass(Registry);
65INITIALIZE_PASS_END(MemorySSAWrapperPass, "memoryssa", "Memory SSA", false,PassInfo *PI = new PassInfo( "Memory SSA", "memoryssa", &
MemorySSAWrapperPass::ID, PassInfo::NormalCtor_t(callDefaultCtor
<MemorySSAWrapperPass>), false, true); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeMemorySSAWrapperPassPassFlag
; void llvm::initializeMemorySSAWrapperPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeMemorySSAWrapperPassPassFlag
, initializeMemorySSAWrapperPassPassOnce, std::ref(Registry))
; }
66 true)PassInfo *PI = new PassInfo( "Memory SSA", "memoryssa", &
MemorySSAWrapperPass::ID, PassInfo::NormalCtor_t(callDefaultCtor
<MemorySSAWrapperPass>), false, true); Registry.registerPass
(*PI, true); return PI; } static llvm::once_flag InitializeMemorySSAWrapperPassPassFlag
; void llvm::initializeMemorySSAWrapperPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeMemorySSAWrapperPassPassFlag
, initializeMemorySSAWrapperPassPassOnce, std::ref(Registry))
; }
67
68INITIALIZE_PASS_BEGIN(MemorySSAPrinterLegacyPass, "print-memoryssa",static void *initializeMemorySSAPrinterLegacyPassPassOnce(PassRegistry
&Registry) {
69 "Memory SSA Printer", false, false)static void *initializeMemorySSAPrinterLegacyPassPassOnce(PassRegistry
&Registry) {
70INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)initializeMemorySSAWrapperPassPass(Registry);
71INITIALIZE_PASS_END(MemorySSAPrinterLegacyPass, "print-memoryssa",PassInfo *PI = new PassInfo( "Memory SSA Printer", "print-memoryssa"
, &MemorySSAPrinterLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<MemorySSAPrinterLegacyPass>), false, false
); Registry.registerPass(*PI, true); return PI; } static llvm
::once_flag InitializeMemorySSAPrinterLegacyPassPassFlag; void
llvm::initializeMemorySSAPrinterLegacyPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeMemorySSAPrinterLegacyPassPassFlag
, initializeMemorySSAPrinterLegacyPassPassOnce, std::ref(Registry
)); }
72 "Memory SSA Printer", false, false)PassInfo *PI = new PassInfo( "Memory SSA Printer", "print-memoryssa"
, &MemorySSAPrinterLegacyPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<MemorySSAPrinterLegacyPass>), false, false
); Registry.registerPass(*PI, true); return PI; } static llvm
::once_flag InitializeMemorySSAPrinterLegacyPassPassFlag; void
llvm::initializeMemorySSAPrinterLegacyPassPass(PassRegistry &
Registry) { llvm::call_once(InitializeMemorySSAPrinterLegacyPassPassFlag
, initializeMemorySSAPrinterLegacyPassPassOnce, std::ref(Registry
)); }
73
74static cl::opt<unsigned> MaxCheckLimit(
75 "memssa-check-limit", cl::Hidden, cl::init(100),
76 cl::desc("The maximum number of stores/phis MemorySSA"
77 "will consider trying to walk past (default = 100)"));
78
79static cl::opt<bool>
80 VerifyMemorySSA("verify-memoryssa", cl::init(false), cl::Hidden,
81 cl::desc("Verify MemorySSA in legacy printer pass."));
82
83namespace llvm {
84
85/// \brief An assembly annotator class to print Memory SSA information in
86/// comments.
87class MemorySSAAnnotatedWriter : public AssemblyAnnotationWriter {
88 friend class MemorySSA;
89
90 const MemorySSA *MSSA;
91
92public:
93 MemorySSAAnnotatedWriter(const MemorySSA *M) : MSSA(M) {}
94
95 void emitBasicBlockStartAnnot(const BasicBlock *BB,
96 formatted_raw_ostream &OS) override {
97 if (MemoryAccess *MA = MSSA->getMemoryAccess(BB))
98 OS << "; " << *MA << "\n";
99 }
100
101 void emitInstructionAnnot(const Instruction *I,
102 formatted_raw_ostream &OS) override {
103 if (MemoryAccess *MA = MSSA->getMemoryAccess(I))
104 OS << "; " << *MA << "\n";
105 }
106};
107
108} // end namespace llvm
109
110namespace {
111
112/// Our current alias analysis API differentiates heavily between calls and
113/// non-calls, and functions called on one usually assert on the other.
114/// This class encapsulates the distinction to simplify other code that wants
115/// "Memory affecting instructions and related data" to use as a key.
116/// For example, this class is used as a densemap key in the use optimizer.
117class MemoryLocOrCall {
118public:
119 bool IsCall = false;
120
121 MemoryLocOrCall() = default;
122 MemoryLocOrCall(MemoryUseOrDef *MUD)
123 : MemoryLocOrCall(MUD->getMemoryInst()) {}
124 MemoryLocOrCall(const MemoryUseOrDef *MUD)
125 : MemoryLocOrCall(MUD->getMemoryInst()) {}
126
127 MemoryLocOrCall(Instruction *Inst) {
128 if (ImmutableCallSite(Inst)) {
129 IsCall = true;
130 CS = ImmutableCallSite(Inst);
131 } else {
132 IsCall = false;
133 // There is no such thing as a memorylocation for a fence inst, and it is
134 // unique in that regard.
135 if (!isa<FenceInst>(Inst))
136 Loc = MemoryLocation::get(Inst);
137 }
138 }
139
140 explicit MemoryLocOrCall(const MemoryLocation &Loc) : Loc(Loc) {}
141
142 ImmutableCallSite getCS() const {
143 assert(IsCall)(static_cast <bool> (IsCall) ? void (0) : __assert_fail
("IsCall", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 143, __extension__ __PRETTY_FUNCTION__))
;
144 return CS;
145 }
146
147 MemoryLocation getLoc() const {
148 assert(!IsCall)(static_cast <bool> (!IsCall) ? void (0) : __assert_fail
("!IsCall", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 148, __extension__ __PRETTY_FUNCTION__))
;
149 return Loc;
150 }
151
152 bool operator==(const MemoryLocOrCall &Other) const {
153 if (IsCall != Other.IsCall)
154 return false;
155
156 if (!IsCall)
157 return Loc == Other.Loc;
158
159 if (CS.getCalledValue() != Other.CS.getCalledValue())
160 return false;
161
162 return CS.arg_size() == Other.CS.arg_size() &&
163 std::equal(CS.arg_begin(), CS.arg_end(), Other.CS.arg_begin());
164 }
165
166private:
167 union {
168 ImmutableCallSite CS;
169 MemoryLocation Loc;
170 };
171};
172
173} // end anonymous namespace
174
175namespace llvm {
176
177template <> struct DenseMapInfo<MemoryLocOrCall> {
178 static inline MemoryLocOrCall getEmptyKey() {
179 return MemoryLocOrCall(DenseMapInfo<MemoryLocation>::getEmptyKey());
180 }
181
182 static inline MemoryLocOrCall getTombstoneKey() {
183 return MemoryLocOrCall(DenseMapInfo<MemoryLocation>::getTombstoneKey());
184 }
185
186 static unsigned getHashValue(const MemoryLocOrCall &MLOC) {
187 if (!MLOC.IsCall)
188 return hash_combine(
189 MLOC.IsCall,
190 DenseMapInfo<MemoryLocation>::getHashValue(MLOC.getLoc()));
191
192 hash_code hash =
193 hash_combine(MLOC.IsCall, DenseMapInfo<const Value *>::getHashValue(
194 MLOC.getCS().getCalledValue()));
195
196 for (const Value *Arg : MLOC.getCS().args())
197 hash = hash_combine(hash, DenseMapInfo<const Value *>::getHashValue(Arg));
198 return hash;
199 }
200
201 static bool isEqual(const MemoryLocOrCall &LHS, const MemoryLocOrCall &RHS) {
202 return LHS == RHS;
203 }
204};
205
206} // end namespace llvm
207
208/// This does one-way checks to see if Use could theoretically be hoisted above
209/// MayClobber. This will not check the other way around.
210///
211/// This assumes that, for the purposes of MemorySSA, Use comes directly after
212/// MayClobber, with no potentially clobbering operations in between them.
213/// (Where potentially clobbering ops are memory barriers, aliased stores, etc.)
214static bool areLoadsReorderable(const LoadInst *Use,
215 const LoadInst *MayClobber) {
216 bool VolatileUse = Use->isVolatile();
217 bool VolatileClobber = MayClobber->isVolatile();
218 // Volatile operations may never be reordered with other volatile operations.
219 if (VolatileUse && VolatileClobber)
220 return false;
221 // Otherwise, volatile doesn't matter here. From the language reference:
222 // 'optimizers may change the order of volatile operations relative to
223 // non-volatile operations.'"
224
225 // If a load is seq_cst, it cannot be moved above other loads. If its ordering
226 // is weaker, it can be moved above other loads. We just need to be sure that
227 // MayClobber isn't an acquire load, because loads can't be moved above
228 // acquire loads.
229 //
230 // Note that this explicitly *does* allow the free reordering of monotonic (or
231 // weaker) loads of the same address.
232 bool SeqCstUse = Use->getOrdering() == AtomicOrdering::SequentiallyConsistent;
233 bool MayClobberIsAcquire = isAtLeastOrStrongerThan(MayClobber->getOrdering(),
234 AtomicOrdering::Acquire);
235 return !(SeqCstUse || MayClobberIsAcquire);
236}
237
238namespace {
239
240struct ClobberAlias {
241 bool IsClobber;
242 Optional<AliasResult> AR;
243};
244
245} // end anonymous namespace
246
247// Return a pair of {IsClobber (bool), AR (AliasResult)}. It relies on AR being
248// ignored if IsClobber = false.
249static ClobberAlias instructionClobbersQuery(MemoryDef *MD,
250 const MemoryLocation &UseLoc,
251 const Instruction *UseInst,
252 AliasAnalysis &AA) {
253 Instruction *DefInst = MD->getMemoryInst();
254 assert(DefInst && "Defining instruction not actually an instruction")(static_cast <bool> (DefInst && "Defining instruction not actually an instruction"
) ? void (0) : __assert_fail ("DefInst && \"Defining instruction not actually an instruction\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 254, __extension__ __PRETTY_FUNCTION__))
;
255 ImmutableCallSite UseCS(UseInst);
256 Optional<AliasResult> AR;
257
258 if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(DefInst)) {
259 // These intrinsics will show up as affecting memory, but they are just
260 // markers.
261 switch (II->getIntrinsicID()) {
262 case Intrinsic::lifetime_start:
263 if (UseCS)
264 return {false, NoAlias};
265 AR = AA.alias(MemoryLocation(II->getArgOperand(1)), UseLoc);
266 return {AR == MustAlias, AR};
267 case Intrinsic::lifetime_end:
268 case Intrinsic::invariant_start:
269 case Intrinsic::invariant_end:
270 case Intrinsic::assume:
271 return {false, NoAlias};
272 default:
273 break;
274 }
275 }
276
277 if (UseCS) {
278 ModRefInfo I = AA.getModRefInfo(DefInst, UseCS);
279 AR = isMustSet(I) ? MustAlias : MayAlias;
280 return {isModOrRefSet(I), AR};
281 }
282
283 if (auto *DefLoad = dyn_cast<LoadInst>(DefInst))
284 if (auto *UseLoad = dyn_cast<LoadInst>(UseInst))
285 return {!areLoadsReorderable(UseLoad, DefLoad), MayAlias};
286
287 ModRefInfo I = AA.getModRefInfo(DefInst, UseLoc);
288 AR = isMustSet(I) ? MustAlias : MayAlias;
289 return {isModSet(I), AR};
290}
291
292static ClobberAlias instructionClobbersQuery(MemoryDef *MD,
293 const MemoryUseOrDef *MU,
294 const MemoryLocOrCall &UseMLOC,
295 AliasAnalysis &AA) {
296 // FIXME: This is a temporary hack to allow a single instructionClobbersQuery
297 // to exist while MemoryLocOrCall is pushed through places.
298 if (UseMLOC.IsCall)
299 return instructionClobbersQuery(MD, MemoryLocation(), MU->getMemoryInst(),
300 AA);
301 return instructionClobbersQuery(MD, UseMLOC.getLoc(), MU->getMemoryInst(),
302 AA);
303}
304
305// Return true when MD may alias MU, return false otherwise.
306bool MemorySSAUtil::defClobbersUseOrDef(MemoryDef *MD, const MemoryUseOrDef *MU,
307 AliasAnalysis &AA) {
308 return instructionClobbersQuery(MD, MU, MemoryLocOrCall(MU), AA).IsClobber;
309}
310
311namespace {
312
313struct UpwardsMemoryQuery {
314 // True if our original query started off as a call
315 bool IsCall = false;
316 // The pointer location we started the query with. This will be empty if
317 // IsCall is true.
318 MemoryLocation StartingLoc;
319 // This is the instruction we were querying about.
320 const Instruction *Inst = nullptr;
321 // The MemoryAccess we actually got called with, used to test local domination
322 const MemoryAccess *OriginalAccess = nullptr;
323 Optional<AliasResult> AR = MayAlias;
324
325 UpwardsMemoryQuery() = default;
326
327 UpwardsMemoryQuery(const Instruction *Inst, const MemoryAccess *Access)
328 : IsCall(ImmutableCallSite(Inst)), Inst(Inst), OriginalAccess(Access) {
329 if (!IsCall)
330 StartingLoc = MemoryLocation::get(Inst);
331 }
332};
333
334} // end anonymous namespace
335
336static bool lifetimeEndsAt(MemoryDef *MD, const MemoryLocation &Loc,
337 AliasAnalysis &AA) {
338 Instruction *Inst = MD->getMemoryInst();
339 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
340 switch (II->getIntrinsicID()) {
341 case Intrinsic::lifetime_end:
342 return AA.isMustAlias(MemoryLocation(II->getArgOperand(1)), Loc);
343 default:
344 return false;
345 }
346 }
347 return false;
348}
349
350static bool isUseTriviallyOptimizableToLiveOnEntry(AliasAnalysis &AA,
351 const Instruction *I) {
352 // If the memory can't be changed, then loads of the memory can't be
353 // clobbered.
354 //
355 // FIXME: We should handle invariant groups, as well. It's a bit harder,
356 // because we need to pay close attention to invariant group barriers.
357 return isa<LoadInst>(I) && (I->getMetadata(LLVMContext::MD_invariant_load) ||
358 AA.pointsToConstantMemory(cast<LoadInst>(I)->
359 getPointerOperand()));
360}
361
362/// Verifies that `Start` is clobbered by `ClobberAt`, and that nothing
363/// inbetween `Start` and `ClobberAt` can clobbers `Start`.
364///
365/// This is meant to be as simple and self-contained as possible. Because it
366/// uses no cache, etc., it can be relatively expensive.
367///
368/// \param Start The MemoryAccess that we want to walk from.
369/// \param ClobberAt A clobber for Start.
370/// \param StartLoc The MemoryLocation for Start.
371/// \param MSSA The MemorySSA isntance that Start and ClobberAt belong to.
372/// \param Query The UpwardsMemoryQuery we used for our search.
373/// \param AA The AliasAnalysis we used for our search.
374static void LLVM_ATTRIBUTE_UNUSED__attribute__((__unused__))
375checkClobberSanity(MemoryAccess *Start, MemoryAccess *ClobberAt,
376 const MemoryLocation &StartLoc, const MemorySSA &MSSA,
377 const UpwardsMemoryQuery &Query, AliasAnalysis &AA) {
378 assert(MSSA.dominates(ClobberAt, Start) && "Clobber doesn't dominate start?")(static_cast <bool> (MSSA.dominates(ClobberAt, Start) &&
"Clobber doesn't dominate start?") ? void (0) : __assert_fail
("MSSA.dominates(ClobberAt, Start) && \"Clobber doesn't dominate start?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 378, __extension__ __PRETTY_FUNCTION__))
;
379
380 if (MSSA.isLiveOnEntryDef(Start)) {
381 assert(MSSA.isLiveOnEntryDef(ClobberAt) &&(static_cast <bool> (MSSA.isLiveOnEntryDef(ClobberAt) &&
"liveOnEntry must clobber itself") ? void (0) : __assert_fail
("MSSA.isLiveOnEntryDef(ClobberAt) && \"liveOnEntry must clobber itself\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 382, __extension__ __PRETTY_FUNCTION__))
382 "liveOnEntry must clobber itself")(static_cast <bool> (MSSA.isLiveOnEntryDef(ClobberAt) &&
"liveOnEntry must clobber itself") ? void (0) : __assert_fail
("MSSA.isLiveOnEntryDef(ClobberAt) && \"liveOnEntry must clobber itself\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 382, __extension__ __PRETTY_FUNCTION__))
;
383 return;
384 }
385
386 bool FoundClobber = false;
387 DenseSet<MemoryAccessPair> VisitedPhis;
388 SmallVector<MemoryAccessPair, 8> Worklist;
389 Worklist.emplace_back(Start, StartLoc);
390 // Walk all paths from Start to ClobberAt, while looking for clobbers. If one
391 // is found, complain.
392 while (!Worklist.empty()) {
393 MemoryAccessPair MAP = Worklist.pop_back_val();
394 // All we care about is that nothing from Start to ClobberAt clobbers Start.
395 // We learn nothing from revisiting nodes.
396 if (!VisitedPhis.insert(MAP).second)
397 continue;
398
399 for (MemoryAccess *MA : def_chain(MAP.first)) {
400 if (MA == ClobberAt) {
401 if (auto *MD = dyn_cast<MemoryDef>(MA)) {
402 // instructionClobbersQuery isn't essentially free, so don't use `|=`,
403 // since it won't let us short-circuit.
404 //
405 // Also, note that this can't be hoisted out of the `Worklist` loop,
406 // since MD may only act as a clobber for 1 of N MemoryLocations.
407 FoundClobber = FoundClobber || MSSA.isLiveOnEntryDef(MD);
408 if (!FoundClobber) {
409 ClobberAlias CA =
410 instructionClobbersQuery(MD, MAP.second, Query.Inst, AA);
411 if (CA.IsClobber) {
412 FoundClobber = true;
413 // Not used: CA.AR;
414 }
415 }
416 }
417 break;
418 }
419
420 // We should never hit liveOnEntry, unless it's the clobber.
421 assert(!MSSA.isLiveOnEntryDef(MA) && "Hit liveOnEntry before clobber?")(static_cast <bool> (!MSSA.isLiveOnEntryDef(MA) &&
"Hit liveOnEntry before clobber?") ? void (0) : __assert_fail
("!MSSA.isLiveOnEntryDef(MA) && \"Hit liveOnEntry before clobber?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 421, __extension__ __PRETTY_FUNCTION__))
;
422
423 if (auto *MD = dyn_cast<MemoryDef>(MA)) {
424 (void)MD;
425 assert(!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA)(static_cast <bool> (!instructionClobbersQuery(MD, MAP.
second, Query.Inst, AA) .IsClobber && "Found clobber before reaching ClobberAt!"
) ? void (0) : __assert_fail ("!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) .IsClobber && \"Found clobber before reaching ClobberAt!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 427, __extension__ __PRETTY_FUNCTION__))
426 .IsClobber &&(static_cast <bool> (!instructionClobbersQuery(MD, MAP.
second, Query.Inst, AA) .IsClobber && "Found clobber before reaching ClobberAt!"
) ? void (0) : __assert_fail ("!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) .IsClobber && \"Found clobber before reaching ClobberAt!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 427, __extension__ __PRETTY_FUNCTION__))
427 "Found clobber before reaching ClobberAt!")(static_cast <bool> (!instructionClobbersQuery(MD, MAP.
second, Query.Inst, AA) .IsClobber && "Found clobber before reaching ClobberAt!"
) ? void (0) : __assert_fail ("!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) .IsClobber && \"Found clobber before reaching ClobberAt!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 427, __extension__ __PRETTY_FUNCTION__))
;
428 continue;
429 }
430
431 assert(isa<MemoryPhi>(MA))(static_cast <bool> (isa<MemoryPhi>(MA)) ? void (
0) : __assert_fail ("isa<MemoryPhi>(MA)", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 431, __extension__ __PRETTY_FUNCTION__))
;
432 Worklist.append(upward_defs_begin({MA, MAP.second}), upward_defs_end());
433 }
434 }
435
436 // If ClobberAt is a MemoryPhi, we can assume something above it acted as a
437 // clobber. Otherwise, `ClobberAt` should've acted as a clobber at some point.
438 assert((isa<MemoryPhi>(ClobberAt) || FoundClobber) &&(static_cast <bool> ((isa<MemoryPhi>(ClobberAt) ||
FoundClobber) && "ClobberAt never acted as a clobber"
) ? void (0) : __assert_fail ("(isa<MemoryPhi>(ClobberAt) || FoundClobber) && \"ClobberAt never acted as a clobber\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 439, __extension__ __PRETTY_FUNCTION__))
439 "ClobberAt never acted as a clobber")(static_cast <bool> ((isa<MemoryPhi>(ClobberAt) ||
FoundClobber) && "ClobberAt never acted as a clobber"
) ? void (0) : __assert_fail ("(isa<MemoryPhi>(ClobberAt) || FoundClobber) && \"ClobberAt never acted as a clobber\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 439, __extension__ __PRETTY_FUNCTION__))
;
440}
441
442namespace {
443
444/// Our algorithm for walking (and trying to optimize) clobbers, all wrapped up
445/// in one class.
446class ClobberWalker {
447 /// Save a few bytes by using unsigned instead of size_t.
448 using ListIndex = unsigned;
449
450 /// Represents a span of contiguous MemoryDefs, potentially ending in a
451 /// MemoryPhi.
452 struct DefPath {
453 MemoryLocation Loc;
454 // Note that, because we always walk in reverse, Last will always dominate
455 // First. Also note that First and Last are inclusive.
456 MemoryAccess *First;
457 MemoryAccess *Last;
458 Optional<ListIndex> Previous;
459
460 DefPath(const MemoryLocation &Loc, MemoryAccess *First, MemoryAccess *Last,
461 Optional<ListIndex> Previous)
462 : Loc(Loc), First(First), Last(Last), Previous(Previous) {}
463
464 DefPath(const MemoryLocation &Loc, MemoryAccess *Init,
465 Optional<ListIndex> Previous)
466 : DefPath(Loc, Init, Init, Previous) {}
467 };
468
469 const MemorySSA &MSSA;
470 AliasAnalysis &AA;
471 DominatorTree &DT;
472 UpwardsMemoryQuery *Query;
473
474 // Phi optimization bookkeeping
475 SmallVector<DefPath, 32> Paths;
476 DenseSet<ConstMemoryAccessPair> VisitedPhis;
477
478 /// Find the nearest def or phi that `From` can legally be optimized to.
479 const MemoryAccess *getWalkTarget(const MemoryPhi *From) const {
480 assert(From->getNumOperands() && "Phi with no operands?")(static_cast <bool> (From->getNumOperands() &&
"Phi with no operands?") ? void (0) : __assert_fail ("From->getNumOperands() && \"Phi with no operands?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 480, __extension__ __PRETTY_FUNCTION__))
;
481
482 BasicBlock *BB = From->getBlock();
483 MemoryAccess *Result = MSSA.getLiveOnEntryDef();
484 DomTreeNode *Node = DT.getNode(BB);
485 while ((Node = Node->getIDom())) {
486 auto *Defs = MSSA.getBlockDefs(Node->getBlock());
487 if (Defs)
488 return &*Defs->rbegin();
489 }
490 return Result;
491 }
492
493 /// Result of calling walkToPhiOrClobber.
494 struct UpwardsWalkResult {
495 /// The "Result" of the walk. Either a clobber, the last thing we walked, or
496 /// both. Include alias info when clobber found.
497 MemoryAccess *Result;
498 bool IsKnownClobber;
499 Optional<AliasResult> AR;
500 };
501
502 /// Walk to the next Phi or Clobber in the def chain starting at Desc.Last.
503 /// This will update Desc.Last as it walks. It will (optionally) also stop at
504 /// StopAt.
505 ///
506 /// This does not test for whether StopAt is a clobber
507 UpwardsWalkResult
508 walkToPhiOrClobber(DefPath &Desc,
509 const MemoryAccess *StopAt = nullptr) const {
510 assert(!isa<MemoryUse>(Desc.Last) && "Uses don't exist in my world")(static_cast <bool> (!isa<MemoryUse>(Desc.Last) &&
"Uses don't exist in my world") ? void (0) : __assert_fail (
"!isa<MemoryUse>(Desc.Last) && \"Uses don't exist in my world\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 510, __extension__ __PRETTY_FUNCTION__))
;
511
512 for (MemoryAccess *Current : def_chain(Desc.Last)) {
513 Desc.Last = Current;
514 if (Current == StopAt)
515 return {Current, false, MayAlias};
516
517 if (auto *MD = dyn_cast<MemoryDef>(Current)) {
518 if (MSSA.isLiveOnEntryDef(MD))
519 return {MD, true, MustAlias};
520 ClobberAlias CA =
521 instructionClobbersQuery(MD, Desc.Loc, Query->Inst, AA);
522 if (CA.IsClobber)
523 return {MD, true, CA.AR};
524 }
525 }
526
527 assert(isa<MemoryPhi>(Desc.Last) &&(static_cast <bool> (isa<MemoryPhi>(Desc.Last) &&
"Ended at a non-clobber that's not a phi?") ? void (0) : __assert_fail
("isa<MemoryPhi>(Desc.Last) && \"Ended at a non-clobber that's not a phi?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 528, __extension__ __PRETTY_FUNCTION__))
528 "Ended at a non-clobber that's not a phi?")(static_cast <bool> (isa<MemoryPhi>(Desc.Last) &&
"Ended at a non-clobber that's not a phi?") ? void (0) : __assert_fail
("isa<MemoryPhi>(Desc.Last) && \"Ended at a non-clobber that's not a phi?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 528, __extension__ __PRETTY_FUNCTION__))
;
529 return {Desc.Last, false, MayAlias};
530 }
531
532 void addSearches(MemoryPhi *Phi, SmallVectorImpl<ListIndex> &PausedSearches,
533 ListIndex PriorNode) {
534 auto UpwardDefs = make_range(upward_defs_begin({Phi, Paths[PriorNode].Loc}),
535 upward_defs_end());
536 for (const MemoryAccessPair &P : UpwardDefs) {
537 PausedSearches.push_back(Paths.size());
538 Paths.emplace_back(P.second, P.first, PriorNode);
539 }
540 }
541
542 /// Represents a search that terminated after finding a clobber. This clobber
543 /// may or may not be present in the path of defs from LastNode..SearchStart,
544 /// since it may have been retrieved from cache.
545 struct TerminatedPath {
546 MemoryAccess *Clobber;
547 ListIndex LastNode;
548 };
549
550 /// Get an access that keeps us from optimizing to the given phi.
551 ///
552 /// PausedSearches is an array of indices into the Paths array. Its incoming
553 /// value is the indices of searches that stopped at the last phi optimization
554 /// target. It's left in an unspecified state.
555 ///
556 /// If this returns None, NewPaused is a vector of searches that terminated
557 /// at StopWhere. Otherwise, NewPaused is left in an unspecified state.
558 Optional<TerminatedPath>
559 getBlockingAccess(const MemoryAccess *StopWhere,
560 SmallVectorImpl<ListIndex> &PausedSearches,
561 SmallVectorImpl<ListIndex> &NewPaused,
562 SmallVectorImpl<TerminatedPath> &Terminated) {
563 assert(!PausedSearches.empty() && "No searches to continue?")(static_cast <bool> (!PausedSearches.empty() &&
"No searches to continue?") ? void (0) : __assert_fail ("!PausedSearches.empty() && \"No searches to continue?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 563, __extension__ __PRETTY_FUNCTION__))
;
564
565 // BFS vs DFS really doesn't make a difference here, so just do a DFS with
566 // PausedSearches as our stack.
567 while (!PausedSearches.empty()) {
568 ListIndex PathIndex = PausedSearches.pop_back_val();
569 DefPath &Node = Paths[PathIndex];
570
571 // If we've already visited this path with this MemoryLocation, we don't
572 // need to do so again.
573 //
574 // NOTE: That we just drop these paths on the ground makes caching
575 // behavior sporadic. e.g. given a diamond:
576 // A
577 // B C
578 // D
579 //
580 // ...If we walk D, B, A, C, we'll only cache the result of phi
581 // optimization for A, B, and D; C will be skipped because it dies here.
582 // This arguably isn't the worst thing ever, since:
583 // - We generally query things in a top-down order, so if we got below D
584 // without needing cache entries for {C, MemLoc}, then chances are
585 // that those cache entries would end up ultimately unused.
586 // - We still cache things for A, so C only needs to walk up a bit.
587 // If this behavior becomes problematic, we can fix without a ton of extra
588 // work.
589 if (!VisitedPhis.insert({Node.Last, Node.Loc}).second)
590 continue;
591
592 UpwardsWalkResult Res = walkToPhiOrClobber(Node, /*StopAt=*/StopWhere);
593 if (Res.IsKnownClobber) {
594 assert(Res.Result != StopWhere)(static_cast <bool> (Res.Result != StopWhere) ? void (0
) : __assert_fail ("Res.Result != StopWhere", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 594, __extension__ __PRETTY_FUNCTION__))
;
595 // If this wasn't a cache hit, we hit a clobber when walking. That's a
596 // failure.
597 TerminatedPath Term{Res.Result, PathIndex};
598 if (!MSSA.dominates(Res.Result, StopWhere))
599 return Term;
600
601 // Otherwise, it's a valid thing to potentially optimize to.
602 Terminated.push_back(Term);
603 continue;
604 }
605
606 if (Res.Result == StopWhere) {
607 // We've hit our target. Save this path off for if we want to continue
608 // walking.
609 NewPaused.push_back(PathIndex);
610 continue;
611 }
612
613 assert(!MSSA.isLiveOnEntryDef(Res.Result) && "liveOnEntry is a clobber")(static_cast <bool> (!MSSA.isLiveOnEntryDef(Res.Result)
&& "liveOnEntry is a clobber") ? void (0) : __assert_fail
("!MSSA.isLiveOnEntryDef(Res.Result) && \"liveOnEntry is a clobber\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 613, __extension__ __PRETTY_FUNCTION__))
;
614 addSearches(cast<MemoryPhi>(Res.Result), PausedSearches, PathIndex);
615 }
616
617 return None;
618 }
619
620 template <typename T, typename Walker>
621 struct generic_def_path_iterator
622 : public iterator_facade_base<generic_def_path_iterator<T, Walker>,
623 std::forward_iterator_tag, T *> {
624 generic_def_path_iterator() = default;
625 generic_def_path_iterator(Walker *W, ListIndex N) : W(W), N(N) {}
626
627 T &operator*() const { return curNode(); }
628
629 generic_def_path_iterator &operator++() {
630 N = curNode().Previous;
631 return *this;
632 }
633
634 bool operator==(const generic_def_path_iterator &O) const {
635 if (N.hasValue() != O.N.hasValue())
636 return false;
637 return !N.hasValue() || *N == *O.N;
638 }
639
640 private:
641 T &curNode() const { return W->Paths[*N]; }
642
643 Walker *W = nullptr;
644 Optional<ListIndex> N = None;
645 };
646
647 using def_path_iterator = generic_def_path_iterator<DefPath, ClobberWalker>;
648 using const_def_path_iterator =
649 generic_def_path_iterator<const DefPath, const ClobberWalker>;
650
651 iterator_range<def_path_iterator> def_path(ListIndex From) {
652 return make_range(def_path_iterator(this, From), def_path_iterator());
653 }
654
655 iterator_range<const_def_path_iterator> const_def_path(ListIndex From) const {
656 return make_range(const_def_path_iterator(this, From),
657 const_def_path_iterator());
658 }
659
660 struct OptznResult {
661 /// The path that contains our result.
662 TerminatedPath PrimaryClobber;
663 /// The paths that we can legally cache back from, but that aren't
664 /// necessarily the result of the Phi optimization.
665 SmallVector<TerminatedPath, 4> OtherClobbers;
666 };
667
668 ListIndex defPathIndex(const DefPath &N) const {
669 // The assert looks nicer if we don't need to do &N
670 const DefPath *NP = &N;
671 assert(!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() &&(static_cast <bool> (!Paths.empty() && NP >=
&Paths.front() && NP <= &Paths.back() &&
"Out of bounds DefPath!") ? void (0) : __assert_fail ("!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() && \"Out of bounds DefPath!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 672, __extension__ __PRETTY_FUNCTION__))
672 "Out of bounds DefPath!")(static_cast <bool> (!Paths.empty() && NP >=
&Paths.front() && NP <= &Paths.back() &&
"Out of bounds DefPath!") ? void (0) : __assert_fail ("!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() && \"Out of bounds DefPath!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 672, __extension__ __PRETTY_FUNCTION__))
;
673 return NP - &Paths.front();
674 }
675
676 /// Try to optimize a phi as best as we can. Returns a SmallVector of Paths
677 /// that act as legal clobbers. Note that this won't return *all* clobbers.
678 ///
679 /// Phi optimization algorithm tl;dr:
680 /// - Find the earliest def/phi, A, we can optimize to
681 /// - Find if all paths from the starting memory access ultimately reach A
682 /// - If not, optimization isn't possible.
683 /// - Otherwise, walk from A to another clobber or phi, A'.
684 /// - If A' is a def, we're done.
685 /// - If A' is a phi, try to optimize it.
686 ///
687 /// A path is a series of {MemoryAccess, MemoryLocation} pairs. A path
688 /// terminates when a MemoryAccess that clobbers said MemoryLocation is found.
689 OptznResult tryOptimizePhi(MemoryPhi *Phi, MemoryAccess *Start,
690 const MemoryLocation &Loc) {
691 assert(Paths.empty() && VisitedPhis.empty() &&(static_cast <bool> (Paths.empty() && VisitedPhis
.empty() && "Reset the optimization state.") ? void (
0) : __assert_fail ("Paths.empty() && VisitedPhis.empty() && \"Reset the optimization state.\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 692, __extension__ __PRETTY_FUNCTION__))
692 "Reset the optimization state.")(static_cast <bool> (Paths.empty() && VisitedPhis
.empty() && "Reset the optimization state.") ? void (
0) : __assert_fail ("Paths.empty() && VisitedPhis.empty() && \"Reset the optimization state.\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 692, __extension__ __PRETTY_FUNCTION__))
;
693
694 Paths.emplace_back(Loc, Start, Phi, None);
695 // Stores how many "valid" optimization nodes we had prior to calling
696 // addSearches/getBlockingAccess. Necessary for caching if we had a blocker.
697 auto PriorPathsSize = Paths.size();
698
699 SmallVector<ListIndex, 16> PausedSearches;
700 SmallVector<ListIndex, 8> NewPaused;
701 SmallVector<TerminatedPath, 4> TerminatedPaths;
702
703 addSearches(Phi, PausedSearches, 0);
704
705 // Moves the TerminatedPath with the "most dominated" Clobber to the end of
706 // Paths.
707 auto MoveDominatedPathToEnd = [&](SmallVectorImpl<TerminatedPath> &Paths) {
708 assert(!Paths.empty() && "Need a path to move")(static_cast <bool> (!Paths.empty() && "Need a path to move"
) ? void (0) : __assert_fail ("!Paths.empty() && \"Need a path to move\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 708, __extension__ __PRETTY_FUNCTION__))
;
709 auto Dom = Paths.begin();
710 for (auto I = std::next(Dom), E = Paths.end(); I != E; ++I)
711 if (!MSSA.dominates(I->Clobber, Dom->Clobber))
712 Dom = I;
713 auto Last = Paths.end() - 1;
714 if (Last != Dom)
715 std::iter_swap(Last, Dom);
716 };
717
718 MemoryPhi *Current = Phi;
719 while (true) {
720 assert(!MSSA.isLiveOnEntryDef(Current) &&(static_cast <bool> (!MSSA.isLiveOnEntryDef(Current) &&
"liveOnEntry wasn't treated as a clobber?") ? void (0) : __assert_fail
("!MSSA.isLiveOnEntryDef(Current) && \"liveOnEntry wasn't treated as a clobber?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 721, __extension__ __PRETTY_FUNCTION__))
721 "liveOnEntry wasn't treated as a clobber?")(static_cast <bool> (!MSSA.isLiveOnEntryDef(Current) &&
"liveOnEntry wasn't treated as a clobber?") ? void (0) : __assert_fail
("!MSSA.isLiveOnEntryDef(Current) && \"liveOnEntry wasn't treated as a clobber?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 721, __extension__ __PRETTY_FUNCTION__))
;
722
723 const auto *Target = getWalkTarget(Current);
724 // If a TerminatedPath doesn't dominate Target, then it wasn't a legal
725 // optimization for the prior phi.
726 assert(all_of(TerminatedPaths, [&](const TerminatedPath &P) {(static_cast <bool> (all_of(TerminatedPaths, [&](const
TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target
); })) ? void (0) : __assert_fail ("all_of(TerminatedPaths, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target); })"
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 728, __extension__ __PRETTY_FUNCTION__))
727 return MSSA.dominates(P.Clobber, Target);(static_cast <bool> (all_of(TerminatedPaths, [&](const
TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target
); })) ? void (0) : __assert_fail ("all_of(TerminatedPaths, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target); })"
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 728, __extension__ __PRETTY_FUNCTION__))
728 }))(static_cast <bool> (all_of(TerminatedPaths, [&](const
TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target
); })) ? void (0) : __assert_fail ("all_of(TerminatedPaths, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target); })"
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 728, __extension__ __PRETTY_FUNCTION__))
;
729
730 // FIXME: This is broken, because the Blocker may be reported to be
731 // liveOnEntry, and we'll happily wait for that to disappear (read: never)
732 // For the moment, this is fine, since we do nothing with blocker info.
733 if (Optional<TerminatedPath> Blocker = getBlockingAccess(
734 Target, PausedSearches, NewPaused, TerminatedPaths)) {
735
736 // Find the node we started at. We can't search based on N->Last, since
737 // we may have gone around a loop with a different MemoryLocation.
738 auto Iter = find_if(def_path(Blocker->LastNode), [&](const DefPath &N) {
739 return defPathIndex(N) < PriorPathsSize;
740 });
741 assert(Iter != def_path_iterator())(static_cast <bool> (Iter != def_path_iterator()) ? void
(0) : __assert_fail ("Iter != def_path_iterator()", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 741, __extension__ __PRETTY_FUNCTION__))
;
742
743 DefPath &CurNode = *Iter;
744 assert(CurNode.Last == Current)(static_cast <bool> (CurNode.Last == Current) ? void (0
) : __assert_fail ("CurNode.Last == Current", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 744, __extension__ __PRETTY_FUNCTION__))
;
745
746 // Two things:
747 // A. We can't reliably cache all of NewPaused back. Consider a case
748 // where we have two paths in NewPaused; one of which can't optimize
749 // above this phi, whereas the other can. If we cache the second path
750 // back, we'll end up with suboptimal cache entries. We can handle
751 // cases like this a bit better when we either try to find all
752 // clobbers that block phi optimization, or when our cache starts
753 // supporting unfinished searches.
754 // B. We can't reliably cache TerminatedPaths back here without doing
755 // extra checks; consider a case like:
756 // T
757 // / \
758 // D C
759 // \ /
760 // S
761 // Where T is our target, C is a node with a clobber on it, D is a
762 // diamond (with a clobber *only* on the left or right node, N), and
763 // S is our start. Say we walk to D, through the node opposite N
764 // (read: ignoring the clobber), and see a cache entry in the top
765 // node of D. That cache entry gets put into TerminatedPaths. We then
766 // walk up to C (N is later in our worklist), find the clobber, and
767 // quit. If we append TerminatedPaths to OtherClobbers, we'll cache
768 // the bottom part of D to the cached clobber, ignoring the clobber
769 // in N. Again, this problem goes away if we start tracking all
770 // blockers for a given phi optimization.
771 TerminatedPath Result{CurNode.Last, defPathIndex(CurNode)};
772 return {Result, {}};
773 }
774
775 // If there's nothing left to search, then all paths led to valid clobbers
776 // that we got from our cache; pick the nearest to the start, and allow
777 // the rest to be cached back.
778 if (NewPaused.empty()) {
779 MoveDominatedPathToEnd(TerminatedPaths);
780 TerminatedPath Result = TerminatedPaths.pop_back_val();
781 return {Result, std::move(TerminatedPaths)};
782 }
783
784 MemoryAccess *DefChainEnd = nullptr;
785 SmallVector<TerminatedPath, 4> Clobbers;
786 for (ListIndex Paused : NewPaused) {
787 UpwardsWalkResult WR = walkToPhiOrClobber(Paths[Paused]);
788 if (WR.IsKnownClobber)
789 Clobbers.push_back({WR.Result, Paused});
790 else
791 // Micro-opt: If we hit the end of the chain, save it.
792 DefChainEnd = WR.Result;
793 }
794
795 if (!TerminatedPaths.empty()) {
796 // If we couldn't find the dominating phi/liveOnEntry in the above loop,
797 // do it now.
798 if (!DefChainEnd)
799 for (auto *MA : def_chain(const_cast<MemoryAccess *>(Target)))
800 DefChainEnd = MA;
801
802 // If any of the terminated paths don't dominate the phi we'll try to
803 // optimize, we need to figure out what they are and quit.
804 const BasicBlock *ChainBB = DefChainEnd->getBlock();
805 for (const TerminatedPath &TP : TerminatedPaths) {
806 // Because we know that DefChainEnd is as "high" as we can go, we
807 // don't need local dominance checks; BB dominance is sufficient.
808 if (DT.dominates(ChainBB, TP.Clobber->getBlock()))
809 Clobbers.push_back(TP);
810 }
811 }
812
813 // If we have clobbers in the def chain, find the one closest to Current
814 // and quit.
815 if (!Clobbers.empty()) {
816 MoveDominatedPathToEnd(Clobbers);
817 TerminatedPath Result = Clobbers.pop_back_val();
818 return {Result, std::move(Clobbers)};
819 }
820
821 assert(all_of(NewPaused,(static_cast <bool> (all_of(NewPaused, [&](ListIndex
I) { return Paths[I].Last == DefChainEnd; })) ? void (0) : __assert_fail
("all_of(NewPaused, [&](ListIndex I) { return Paths[I].Last == DefChainEnd; })"
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 822, __extension__ __PRETTY_FUNCTION__))
822 [&](ListIndex I) { return Paths[I].Last == DefChainEnd; }))(static_cast <bool> (all_of(NewPaused, [&](ListIndex
I) { return Paths[I].Last == DefChainEnd; })) ? void (0) : __assert_fail
("all_of(NewPaused, [&](ListIndex I) { return Paths[I].Last == DefChainEnd; })"
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 822, __extension__ __PRETTY_FUNCTION__))
;
823
824 // Because liveOnEntry is a clobber, this must be a phi.
825 auto *DefChainPhi = cast<MemoryPhi>(DefChainEnd);
826
827 PriorPathsSize = Paths.size();
828 PausedSearches.clear();
829 for (ListIndex I : NewPaused)
830 addSearches(DefChainPhi, PausedSearches, I);
831 NewPaused.clear();
832
833 Current = DefChainPhi;
834 }
835 }
836
837 void verifyOptResult(const OptznResult &R) const {
838 assert(all_of(R.OtherClobbers, [&](const TerminatedPath &P) {(static_cast <bool> (all_of(R.OtherClobbers, [&](const
TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.
PrimaryClobber.Clobber); })) ? void (0) : __assert_fail ("all_of(R.OtherClobbers, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber); })"
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 840, __extension__ __PRETTY_FUNCTION__))
839 return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber);(static_cast <bool> (all_of(R.OtherClobbers, [&](const
TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.
PrimaryClobber.Clobber); })) ? void (0) : __assert_fail ("all_of(R.OtherClobbers, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber); })"
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 840, __extension__ __PRETTY_FUNCTION__))
840 }))(static_cast <bool> (all_of(R.OtherClobbers, [&](const
TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.
PrimaryClobber.Clobber); })) ? void (0) : __assert_fail ("all_of(R.OtherClobbers, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber); })"
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 840, __extension__ __PRETTY_FUNCTION__))
;
841 }
842
843 void resetPhiOptznState() {
844 Paths.clear();
845 VisitedPhis.clear();
846 }
847
848public:
849 ClobberWalker(const MemorySSA &MSSA, AliasAnalysis &AA, DominatorTree &DT)
850 : MSSA(MSSA), AA(AA), DT(DT) {}
851
852 /// Finds the nearest clobber for the given query, optimizing phis if
853 /// possible.
854 MemoryAccess *findClobber(MemoryAccess *Start, UpwardsMemoryQuery &Q) {
855 Query = &Q;
856
857 MemoryAccess *Current = Start;
858 // This walker pretends uses don't exist. If we're handed one, silently grab
859 // its def. (This has the nice side-effect of ensuring we never cache uses)
860 if (auto *MU = dyn_cast<MemoryUse>(Start))
861 Current = MU->getDefiningAccess();
862
863 DefPath FirstDesc(Q.StartingLoc, Current, Current, None);
864 // Fast path for the overly-common case (no crazy phi optimization
865 // necessary)
866 UpwardsWalkResult WalkResult = walkToPhiOrClobber(FirstDesc);
867 MemoryAccess *Result;
868 if (WalkResult.IsKnownClobber) {
869 Result = WalkResult.Result;
870 Q.AR = WalkResult.AR;
871 } else {
872 OptznResult OptRes = tryOptimizePhi(cast<MemoryPhi>(FirstDesc.Last),
873 Current, Q.StartingLoc);
874 verifyOptResult(OptRes);
875 resetPhiOptznState();
876 Result = OptRes.PrimaryClobber.Clobber;
877 }
878
879#ifdef EXPENSIVE_CHECKS
880 checkClobberSanity(Current, Result, Q.StartingLoc, MSSA, Q, AA);
881#endif
882 return Result;
883 }
884
885 void verify(const MemorySSA *MSSA) { assert(MSSA == &this->MSSA)(static_cast <bool> (MSSA == &this->MSSA) ? void
(0) : __assert_fail ("MSSA == &this->MSSA", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 885, __extension__ __PRETTY_FUNCTION__))
; }
886};
887
888struct RenamePassData {
889 DomTreeNode *DTN;
890 DomTreeNode::const_iterator ChildIt;
891 MemoryAccess *IncomingVal;
892
893 RenamePassData(DomTreeNode *D, DomTreeNode::const_iterator It,
894 MemoryAccess *M)
895 : DTN(D), ChildIt(It), IncomingVal(M) {}
896
897 void swap(RenamePassData &RHS) {
898 std::swap(DTN, RHS.DTN);
899 std::swap(ChildIt, RHS.ChildIt);
900 std::swap(IncomingVal, RHS.IncomingVal);
901 }
902};
903
904} // end anonymous namespace
905
906namespace llvm {
907
908/// \brief A MemorySSAWalker that does AA walks to disambiguate accesses. It no
909/// longer does caching on its own,
910/// but the name has been retained for the moment.
911class MemorySSA::CachingWalker final : public MemorySSAWalker {
912 ClobberWalker Walker;
913
914 MemoryAccess *getClobberingMemoryAccess(MemoryAccess *, UpwardsMemoryQuery &);
915
916public:
917 CachingWalker(MemorySSA *, AliasAnalysis *, DominatorTree *);
918 ~CachingWalker() override = default;
919
920 using MemorySSAWalker::getClobberingMemoryAccess;
921
922 MemoryAccess *getClobberingMemoryAccess(MemoryAccess *) override;
923 MemoryAccess *getClobberingMemoryAccess(MemoryAccess *,
924 const MemoryLocation &) override;
925 void invalidateInfo(MemoryAccess *) override;
926
927 void verify(const MemorySSA *MSSA) override {
928 MemorySSAWalker::verify(MSSA);
929 Walker.verify(MSSA);
930 }
931};
932
933} // end namespace llvm
934
935void MemorySSA::renameSuccessorPhis(BasicBlock *BB, MemoryAccess *IncomingVal,
936 bool RenameAllUses) {
937 // Pass through values to our successors
938 for (const BasicBlock *S : successors(BB)) {
939 auto It = PerBlockAccesses.find(S);
940 // Rename the phi nodes in our successor block
941 if (It == PerBlockAccesses.end() || !isa<MemoryPhi>(It->second->front()))
942 continue;
943 AccessList *Accesses = It->second.get();
944 auto *Phi = cast<MemoryPhi>(&Accesses->front());
945 if (RenameAllUses) {
946 int PhiIndex = Phi->getBasicBlockIndex(BB);
947 assert(PhiIndex != -1 && "Incomplete phi during partial rename")(static_cast <bool> (PhiIndex != -1 && "Incomplete phi during partial rename"
) ? void (0) : __assert_fail ("PhiIndex != -1 && \"Incomplete phi during partial rename\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 947, __extension__ __PRETTY_FUNCTION__))
;
948 Phi->setIncomingValue(PhiIndex, IncomingVal);
949 } else
950 Phi->addIncoming(IncomingVal, BB);
951 }
952}
953
954/// \brief Rename a single basic block into MemorySSA form.
955/// Uses the standard SSA renaming algorithm.
956/// \returns The new incoming value.
957MemoryAccess *MemorySSA::renameBlock(BasicBlock *BB, MemoryAccess *IncomingVal,
958 bool RenameAllUses) {
959 auto It = PerBlockAccesses.find(BB);
960 // Skip most processing if the list is empty.
961 if (It != PerBlockAccesses.end()) {
962 AccessList *Accesses = It->second.get();
963 for (MemoryAccess &L : *Accesses) {
964 if (MemoryUseOrDef *MUD = dyn_cast<MemoryUseOrDef>(&L)) {
965 if (MUD->getDefiningAccess() == nullptr || RenameAllUses)
966 MUD->setDefiningAccess(IncomingVal);
967 if (isa<MemoryDef>(&L))
968 IncomingVal = &L;
969 } else {
970 IncomingVal = &L;
971 }
972 }
973 }
974 return IncomingVal;
975}
976
977/// \brief This is the standard SSA renaming algorithm.
978///
979/// We walk the dominator tree in preorder, renaming accesses, and then filling
980/// in phi nodes in our successors.
981void MemorySSA::renamePass(DomTreeNode *Root, MemoryAccess *IncomingVal,
982 SmallPtrSetImpl<BasicBlock *> &Visited,
983 bool SkipVisited, bool RenameAllUses) {
984 SmallVector<RenamePassData, 32> WorkStack;
985 // Skip everything if we already renamed this block and we are skipping.
986 // Note: You can't sink this into the if, because we need it to occur
987 // regardless of whether we skip blocks or not.
988 bool AlreadyVisited = !Visited.insert(Root->getBlock()).second;
989 if (SkipVisited && AlreadyVisited)
990 return;
991
992 IncomingVal = renameBlock(Root->getBlock(), IncomingVal, RenameAllUses);
993 renameSuccessorPhis(Root->getBlock(), IncomingVal, RenameAllUses);
994 WorkStack.push_back({Root, Root->begin(), IncomingVal});
995
996 while (!WorkStack.empty()) {
997 DomTreeNode *Node = WorkStack.back().DTN;
998 DomTreeNode::const_iterator ChildIt = WorkStack.back().ChildIt;
999 IncomingVal = WorkStack.back().IncomingVal;
1000
1001 if (ChildIt == Node->end()) {
1002 WorkStack.pop_back();
1003 } else {
1004 DomTreeNode *Child = *ChildIt;
1005 ++WorkStack.back().ChildIt;
1006 BasicBlock *BB = Child->getBlock();
1007 // Note: You can't sink this into the if, because we need it to occur
1008 // regardless of whether we skip blocks or not.
1009 AlreadyVisited = !Visited.insert(BB).second;
1010 if (SkipVisited && AlreadyVisited) {
1011 // We already visited this during our renaming, which can happen when
1012 // being asked to rename multiple blocks. Figure out the incoming val,
1013 // which is the last def.
1014 // Incoming value can only change if there is a block def, and in that
1015 // case, it's the last block def in the list.
1016 if (auto *BlockDefs = getWritableBlockDefs(BB))
1017 IncomingVal = &*BlockDefs->rbegin();
1018 } else
1019 IncomingVal = renameBlock(BB, IncomingVal, RenameAllUses);
1020 renameSuccessorPhis(BB, IncomingVal, RenameAllUses);
1021 WorkStack.push_back({Child, Child->begin(), IncomingVal});
1022 }
1023 }
1024}
1025
1026/// \brief This handles unreachable block accesses by deleting phi nodes in
1027/// unreachable blocks, and marking all other unreachable MemoryAccess's as
1028/// being uses of the live on entry definition.
1029void MemorySSA::markUnreachableAsLiveOnEntry(BasicBlock *BB) {
1030 assert(!DT->isReachableFromEntry(BB) &&(static_cast <bool> (!DT->isReachableFromEntry(BB) &&
"Reachable block found while handling unreachable blocks") ?
void (0) : __assert_fail ("!DT->isReachableFromEntry(BB) && \"Reachable block found while handling unreachable blocks\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1031, __extension__ __PRETTY_FUNCTION__))
1031 "Reachable block found while handling unreachable blocks")(static_cast <bool> (!DT->isReachableFromEntry(BB) &&
"Reachable block found while handling unreachable blocks") ?
void (0) : __assert_fail ("!DT->isReachableFromEntry(BB) && \"Reachable block found while handling unreachable blocks\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1031, __extension__ __PRETTY_FUNCTION__))
;
1032
1033 // Make sure phi nodes in our reachable successors end up with a
1034 // LiveOnEntryDef for our incoming edge, even though our block is forward
1035 // unreachable. We could just disconnect these blocks from the CFG fully,
1036 // but we do not right now.
1037 for (const BasicBlock *S : successors(BB)) {
1038 if (!DT->isReachableFromEntry(S))
1039 continue;
1040 auto It = PerBlockAccesses.find(S);
1041 // Rename the phi nodes in our successor block
1042 if (It == PerBlockAccesses.end() || !isa<MemoryPhi>(It->second->front()))
1043 continue;
1044 AccessList *Accesses = It->second.get();
1045 auto *Phi = cast<MemoryPhi>(&Accesses->front());
1046 Phi->addIncoming(LiveOnEntryDef.get(), BB);
1047 }
1048
1049 auto It = PerBlockAccesses.find(BB);
1050 if (It == PerBlockAccesses.end())
1051 return;
1052
1053 auto &Accesses = It->second;
1054 for (auto AI = Accesses->begin(), AE = Accesses->end(); AI != AE;) {
1055 auto Next = std::next(AI);
1056 // If we have a phi, just remove it. We are going to replace all
1057 // users with live on entry.
1058 if (auto *UseOrDef = dyn_cast<MemoryUseOrDef>(AI))
1059 UseOrDef->setDefiningAccess(LiveOnEntryDef.get());
1060 else
1061 Accesses->erase(AI);
1062 AI = Next;
1063 }
1064}
1065
1066MemorySSA::MemorySSA(Function &Func, AliasAnalysis *AA, DominatorTree *DT)
1067 : AA(AA), DT(DT), F(Func), LiveOnEntryDef(nullptr), Walker(nullptr),
1068 NextID(0) {
1069 buildMemorySSA();
1070}
1071
1072MemorySSA::~MemorySSA() {
1073 // Drop all our references
1074 for (const auto &Pair : PerBlockAccesses)
1075 for (MemoryAccess &MA : *Pair.second)
1076 MA.dropAllReferences();
1077}
1078
1079MemorySSA::AccessList *MemorySSA::getOrCreateAccessList(const BasicBlock *BB) {
1080 auto Res = PerBlockAccesses.insert(std::make_pair(BB, nullptr));
1081
1082 if (Res.second)
1083 Res.first->second = llvm::make_unique<AccessList>();
1084 return Res.first->second.get();
1085}
1086
1087MemorySSA::DefsList *MemorySSA::getOrCreateDefsList(const BasicBlock *BB) {
1088 auto Res = PerBlockDefs.insert(std::make_pair(BB, nullptr));
1089
1090 if (Res.second)
1091 Res.first->second = llvm::make_unique<DefsList>();
1092 return Res.first->second.get();
1093}
1094
1095namespace llvm {
1096
1097/// This class is a batch walker of all MemoryUse's in the program, and points
1098/// their defining access at the thing that actually clobbers them. Because it
1099/// is a batch walker that touches everything, it does not operate like the
1100/// other walkers. This walker is basically performing a top-down SSA renaming
1101/// pass, where the version stack is used as the cache. This enables it to be
1102/// significantly more time and memory efficient than using the regular walker,
1103/// which is walking bottom-up.
1104class MemorySSA::OptimizeUses {
1105public:
1106 OptimizeUses(MemorySSA *MSSA, MemorySSAWalker *Walker, AliasAnalysis *AA,
1107 DominatorTree *DT)
1108 : MSSA(MSSA), Walker(Walker), AA(AA), DT(DT) {
1109 Walker = MSSA->getWalker();
1110 }
1111
1112 void optimizeUses();
1113
1114private:
1115 /// This represents where a given memorylocation is in the stack.
1116 struct MemlocStackInfo {
1117 // This essentially is keeping track of versions of the stack. Whenever
1118 // the stack changes due to pushes or pops, these versions increase.
1119 unsigned long StackEpoch;
1120 unsigned long PopEpoch;
1121 // This is the lower bound of places on the stack to check. It is equal to
1122 // the place the last stack walk ended.
1123 // Note: Correctness depends on this being initialized to 0, which densemap
1124 // does
1125 unsigned long LowerBound;
1126 const BasicBlock *LowerBoundBlock;
1127 // This is where the last walk for this memory location ended.
1128 unsigned long LastKill;
1129 bool LastKillValid;
1130 Optional<AliasResult> AR;
1131 };
1132
1133 void optimizeUsesInBlock(const BasicBlock *, unsigned long &, unsigned long &,
1134 SmallVectorImpl<MemoryAccess *> &,
1135 DenseMap<MemoryLocOrCall, MemlocStackInfo> &);
1136
1137 MemorySSA *MSSA;
1138 MemorySSAWalker *Walker;
1139 AliasAnalysis *AA;
1140 DominatorTree *DT;
1141};
1142
1143} // end namespace llvm
1144
1145/// Optimize the uses in a given block This is basically the SSA renaming
1146/// algorithm, with one caveat: We are able to use a single stack for all
1147/// MemoryUses. This is because the set of *possible* reaching MemoryDefs is
1148/// the same for every MemoryUse. The *actual* clobbering MemoryDef is just
1149/// going to be some position in that stack of possible ones.
1150///
1151/// We track the stack positions that each MemoryLocation needs
1152/// to check, and last ended at. This is because we only want to check the
1153/// things that changed since last time. The same MemoryLocation should
1154/// get clobbered by the same store (getModRefInfo does not use invariantness or
1155/// things like this, and if they start, we can modify MemoryLocOrCall to
1156/// include relevant data)
1157void MemorySSA::OptimizeUses::optimizeUsesInBlock(
1158 const BasicBlock *BB, unsigned long &StackEpoch, unsigned long &PopEpoch,
1159 SmallVectorImpl<MemoryAccess *> &VersionStack,
1160 DenseMap<MemoryLocOrCall, MemlocStackInfo> &LocStackInfo) {
1161
1162 /// If no accesses, nothing to do.
1163 MemorySSA::AccessList *Accesses = MSSA->getWritableBlockAccesses(BB);
1164 if (Accesses == nullptr)
1165 return;
1166
1167 // Pop everything that doesn't dominate the current block off the stack,
1168 // increment the PopEpoch to account for this.
1169 while (true) {
1170 assert((static_cast <bool> (!VersionStack.empty() && "Version stack should have liveOnEntry sentinel dominating everything"
) ? void (0) : __assert_fail ("!VersionStack.empty() && \"Version stack should have liveOnEntry sentinel dominating everything\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1172, __extension__ __PRETTY_FUNCTION__))
1171 !VersionStack.empty() &&(static_cast <bool> (!VersionStack.empty() && "Version stack should have liveOnEntry sentinel dominating everything"
) ? void (0) : __assert_fail ("!VersionStack.empty() && \"Version stack should have liveOnEntry sentinel dominating everything\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1172, __extension__ __PRETTY_FUNCTION__))
1172 "Version stack should have liveOnEntry sentinel dominating everything")(static_cast <bool> (!VersionStack.empty() && "Version stack should have liveOnEntry sentinel dominating everything"
) ? void (0) : __assert_fail ("!VersionStack.empty() && \"Version stack should have liveOnEntry sentinel dominating everything\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1172, __extension__ __PRETTY_FUNCTION__))
;
1173 BasicBlock *BackBlock = VersionStack.back()->getBlock();
1174 if (DT->dominates(BackBlock, BB))
1175 break;
1176 while (VersionStack.back()->getBlock() == BackBlock)
1177 VersionStack.pop_back();
1178 ++PopEpoch;
1179 }
1180
1181 for (MemoryAccess &MA : *Accesses) {
1182 auto *MU = dyn_cast<MemoryUse>(&MA);
1183 if (!MU) {
1184 VersionStack.push_back(&MA);
1185 ++StackEpoch;
1186 continue;
1187 }
1188
1189 if (isUseTriviallyOptimizableToLiveOnEntry(*AA, MU->getMemoryInst())) {
1190 MU->setDefiningAccess(MSSA->getLiveOnEntryDef(), true, None);
1191 continue;
1192 }
1193
1194 MemoryLocOrCall UseMLOC(MU);
1195 auto &LocInfo = LocStackInfo[UseMLOC];
1196 // If the pop epoch changed, it means we've removed stuff from top of
1197 // stack due to changing blocks. We may have to reset the lower bound or
1198 // last kill info.
1199 if (LocInfo.PopEpoch != PopEpoch) {
1200 LocInfo.PopEpoch = PopEpoch;
1201 LocInfo.StackEpoch = StackEpoch;
1202 // If the lower bound was in something that no longer dominates us, we
1203 // have to reset it.
1204 // We can't simply track stack size, because the stack may have had
1205 // pushes/pops in the meantime.
1206 // XXX: This is non-optimal, but only is slower cases with heavily
1207 // branching dominator trees. To get the optimal number of queries would
1208 // be to make lowerbound and lastkill a per-loc stack, and pop it until
1209 // the top of that stack dominates us. This does not seem worth it ATM.
1210 // A much cheaper optimization would be to always explore the deepest
1211 // branch of the dominator tree first. This will guarantee this resets on
1212 // the smallest set of blocks.
1213 if (LocInfo.LowerBoundBlock && LocInfo.LowerBoundBlock != BB &&
1214 !DT->dominates(LocInfo.LowerBoundBlock, BB)) {
1215 // Reset the lower bound of things to check.
1216 // TODO: Some day we should be able to reset to last kill, rather than
1217 // 0.
1218 LocInfo.LowerBound = 0;
1219 LocInfo.LowerBoundBlock = VersionStack[0]->getBlock();
1220 LocInfo.LastKillValid = false;
1221 }
1222 } else if (LocInfo.StackEpoch != StackEpoch) {
1223 // If all that has changed is the StackEpoch, we only have to check the
1224 // new things on the stack, because we've checked everything before. In
1225 // this case, the lower bound of things to check remains the same.
1226 LocInfo.PopEpoch = PopEpoch;
1227 LocInfo.StackEpoch = StackEpoch;
1228 }
1229 if (!LocInfo.LastKillValid) {
1230 LocInfo.LastKill = VersionStack.size() - 1;
1231 LocInfo.LastKillValid = true;
1232 LocInfo.AR = MayAlias;
1233 }
1234
1235 // At this point, we should have corrected last kill and LowerBound to be
1236 // in bounds.
1237 assert(LocInfo.LowerBound < VersionStack.size() &&(static_cast <bool> (LocInfo.LowerBound < VersionStack
.size() && "Lower bound out of range") ? void (0) : __assert_fail
("LocInfo.LowerBound < VersionStack.size() && \"Lower bound out of range\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1238, __extension__ __PRETTY_FUNCTION__))
1238 "Lower bound out of range")(static_cast <bool> (LocInfo.LowerBound < VersionStack
.size() && "Lower bound out of range") ? void (0) : __assert_fail
("LocInfo.LowerBound < VersionStack.size() && \"Lower bound out of range\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1238, __extension__ __PRETTY_FUNCTION__))
;
1239 assert(LocInfo.LastKill < VersionStack.size() &&(static_cast <bool> (LocInfo.LastKill < VersionStack
.size() && "Last kill info out of range") ? void (0) :
__assert_fail ("LocInfo.LastKill < VersionStack.size() && \"Last kill info out of range\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1240, __extension__ __PRETTY_FUNCTION__))
1240 "Last kill info out of range")(static_cast <bool> (LocInfo.LastKill < VersionStack
.size() && "Last kill info out of range") ? void (0) :
__assert_fail ("LocInfo.LastKill < VersionStack.size() && \"Last kill info out of range\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1240, __extension__ __PRETTY_FUNCTION__))
;
1241 // In any case, the new upper bound is the top of the stack.
1242 unsigned long UpperBound = VersionStack.size() - 1;
1243
1244 if (UpperBound - LocInfo.LowerBound > MaxCheckLimit) {
1245 DEBUG(dbgs() << "MemorySSA skipping optimization of " << *MU << " ("do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "MemorySSA skipping optimization of "
<< *MU << " (" << *(MU->getMemoryInst()
) << ")" << " because there are " << UpperBound
- LocInfo.LowerBound << " stores to disambiguate\n"; }
} while (false)
1246 << *(MU->getMemoryInst()) << ")"do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "MemorySSA skipping optimization of "
<< *MU << " (" << *(MU->getMemoryInst()
) << ")" << " because there are " << UpperBound
- LocInfo.LowerBound << " stores to disambiguate\n"; }
} while (false)
1247 << " because there are " << UpperBound - LocInfo.LowerBounddo { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "MemorySSA skipping optimization of "
<< *MU << " (" << *(MU->getMemoryInst()
) << ")" << " because there are " << UpperBound
- LocInfo.LowerBound << " stores to disambiguate\n"; }
} while (false)
1248 << " stores to disambiguate\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "MemorySSA skipping optimization of "
<< *MU << " (" << *(MU->getMemoryInst()
) << ")" << " because there are " << UpperBound
- LocInfo.LowerBound << " stores to disambiguate\n"; }
} while (false)
;
1249 // Because we did not walk, LastKill is no longer valid, as this may
1250 // have been a kill.
1251 LocInfo.LastKillValid = false;
1252 continue;
1253 }
1254 bool FoundClobberResult = false;
1255 while (UpperBound > LocInfo.LowerBound) {
1256 if (isa<MemoryPhi>(VersionStack[UpperBound])) {
1257 // For phis, use the walker, see where we ended up, go there
1258 Instruction *UseInst = MU->getMemoryInst();
1259 MemoryAccess *Result = Walker->getClobberingMemoryAccess(UseInst);
1260 // We are guaranteed to find it or something is wrong
1261 while (VersionStack[UpperBound] != Result) {
1262 assert(UpperBound != 0)(static_cast <bool> (UpperBound != 0) ? void (0) : __assert_fail
("UpperBound != 0", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1262, __extension__ __PRETTY_FUNCTION__))
;
1263 --UpperBound;
1264 }
1265 FoundClobberResult = true;
1266 break;
1267 }
1268
1269 MemoryDef *MD = cast<MemoryDef>(VersionStack[UpperBound]);
1270 // If the lifetime of the pointer ends at this instruction, it's live on
1271 // entry.
1272 if (!UseMLOC.IsCall && lifetimeEndsAt(MD, UseMLOC.getLoc(), *AA)) {
1273 // Reset UpperBound to liveOnEntryDef's place in the stack
1274 UpperBound = 0;
1275 FoundClobberResult = true;
1276 LocInfo.AR = MustAlias;
1277 break;
1278 }
1279 ClobberAlias CA = instructionClobbersQuery(MD, MU, UseMLOC, *AA);
1280 if (CA.IsClobber) {
1281 FoundClobberResult = true;
1282 LocInfo.AR = CA.AR;
1283 break;
1284 }
1285 --UpperBound;
1286 }
1287
1288 // Note: Phis always have AliasResult AR set to MayAlias ATM.
1289
1290 // At the end of this loop, UpperBound is either a clobber, or lower bound
1291 // PHI walking may cause it to be < LowerBound, and in fact, < LastKill.
1292 if (FoundClobberResult || UpperBound < LocInfo.LastKill) {
1293 // We were last killed now by where we got to
1294 if (MSSA->isLiveOnEntryDef(VersionStack[UpperBound]))
1295 LocInfo.AR = None;
1296 MU->setDefiningAccess(VersionStack[UpperBound], true, LocInfo.AR);
1297 LocInfo.LastKill = UpperBound;
1298 } else {
1299 // Otherwise, we checked all the new ones, and now we know we can get to
1300 // LastKill.
1301 MU->setDefiningAccess(VersionStack[LocInfo.LastKill], true, LocInfo.AR);
1302 }
1303 LocInfo.LowerBound = VersionStack.size() - 1;
1304 LocInfo.LowerBoundBlock = BB;
1305 }
1306}
1307
1308/// Optimize uses to point to their actual clobbering definitions.
1309void MemorySSA::OptimizeUses::optimizeUses() {
1310 SmallVector<MemoryAccess *, 16> VersionStack;
1311 DenseMap<MemoryLocOrCall, MemlocStackInfo> LocStackInfo;
1312 VersionStack.push_back(MSSA->getLiveOnEntryDef());
1313
1314 unsigned long StackEpoch = 1;
1315 unsigned long PopEpoch = 1;
1316 // We perform a non-recursive top-down dominator tree walk.
1317 for (const auto *DomNode : depth_first(DT->getRootNode()))
1318 optimizeUsesInBlock(DomNode->getBlock(), StackEpoch, PopEpoch, VersionStack,
1319 LocStackInfo);
1320}
1321
1322void MemorySSA::placePHINodes(
1323 const SmallPtrSetImpl<BasicBlock *> &DefiningBlocks,
1324 const DenseMap<const BasicBlock *, unsigned int> &BBNumbers) {
1325 // Determine where our MemoryPhi's should go
1326 ForwardIDFCalculator IDFs(*DT);
1327 IDFs.setDefiningBlocks(DefiningBlocks);
1328 SmallVector<BasicBlock *, 32> IDFBlocks;
1329 IDFs.calculate(IDFBlocks);
1330
1331 llvm::sort(IDFBlocks.begin(), IDFBlocks.end(),
1332 [&BBNumbers](const BasicBlock *A, const BasicBlock *B) {
1333 return BBNumbers.lookup(A) < BBNumbers.lookup(B);
1334 });
1335
1336 // Now place MemoryPhi nodes.
1337 for (auto &BB : IDFBlocks)
1338 createMemoryPhi(BB);
1339}
1340
1341void MemorySSA::buildMemorySSA() {
1342 // We create an access to represent "live on entry", for things like
1343 // arguments or users of globals, where the memory they use is defined before
1344 // the beginning of the function. We do not actually insert it into the IR.
1345 // We do not define a live on exit for the immediate uses, and thus our
1346 // semantics do *not* imply that something with no immediate uses can simply
1347 // be removed.
1348 BasicBlock &StartingPoint = F.getEntryBlock();
1349 LiveOnEntryDef.reset(new MemoryDef(F.getContext(), nullptr, nullptr,
1350 &StartingPoint, NextID++));
1351 DenseMap<const BasicBlock *, unsigned int> BBNumbers;
1352 unsigned NextBBNum = 0;
1353
1354 // We maintain lists of memory accesses per-block, trading memory for time. We
1355 // could just look up the memory access for every possible instruction in the
1356 // stream.
1357 SmallPtrSet<BasicBlock *, 32> DefiningBlocks;
1358 // Go through each block, figure out where defs occur, and chain together all
1359 // the accesses.
1360 for (BasicBlock &B : F) {
1361 BBNumbers[&B] = NextBBNum++;
1362 bool InsertIntoDef = false;
1363 AccessList *Accesses = nullptr;
1364 DefsList *Defs = nullptr;
1365 for (Instruction &I : B) {
1366 MemoryUseOrDef *MUD = createNewAccess(&I);
1367 if (!MUD)
1368 continue;
1369
1370 if (!Accesses)
1371 Accesses = getOrCreateAccessList(&B);
1372 Accesses->push_back(MUD);
1373 if (isa<MemoryDef>(MUD)) {
1374 InsertIntoDef = true;
1375 if (!Defs)
1376 Defs = getOrCreateDefsList(&B);
1377 Defs->push_back(*MUD);
1378 }
1379 }
1380 if (InsertIntoDef)
1381 DefiningBlocks.insert(&B);
1382 }
1383 placePHINodes(DefiningBlocks, BBNumbers);
1384
1385 // Now do regular SSA renaming on the MemoryDef/MemoryUse. Visited will get
1386 // filled in with all blocks.
1387 SmallPtrSet<BasicBlock *, 16> Visited;
1388 renamePass(DT->getRootNode(), LiveOnEntryDef.get(), Visited);
1389
1390 CachingWalker *Walker = getWalkerImpl();
1391
1392 OptimizeUses(this, Walker, AA, DT).optimizeUses();
1393
1394 // Mark the uses in unreachable blocks as live on entry, so that they go
1395 // somewhere.
1396 for (auto &BB : F)
1397 if (!Visited.count(&BB))
1398 markUnreachableAsLiveOnEntry(&BB);
1399}
1400
1401MemorySSAWalker *MemorySSA::getWalker() { return getWalkerImpl(); }
1402
1403MemorySSA::CachingWalker *MemorySSA::getWalkerImpl() {
1404 if (Walker)
1405 return Walker.get();
1406
1407 Walker = llvm::make_unique<CachingWalker>(this, AA, DT);
1408 return Walker.get();
1409}
1410
1411// This is a helper function used by the creation routines. It places NewAccess
1412// into the access and defs lists for a given basic block, at the given
1413// insertion point.
1414void MemorySSA::insertIntoListsForBlock(MemoryAccess *NewAccess,
1415 const BasicBlock *BB,
1416 InsertionPlace Point) {
1417 auto *Accesses = getOrCreateAccessList(BB);
1418 if (Point == Beginning) {
1419 // If it's a phi node, it goes first, otherwise, it goes after any phi
1420 // nodes.
1421 if (isa<MemoryPhi>(NewAccess)) {
1422 Accesses->push_front(NewAccess);
1423 auto *Defs = getOrCreateDefsList(BB);
1424 Defs->push_front(*NewAccess);
1425 } else {
1426 auto AI = find_if_not(
1427 *Accesses, [](const MemoryAccess &MA) { return isa<MemoryPhi>(MA); });
1428 Accesses->insert(AI, NewAccess);
1429 if (!isa<MemoryUse>(NewAccess)) {
1430 auto *Defs = getOrCreateDefsList(BB);
1431 auto DI = find_if_not(
1432 *Defs, [](const MemoryAccess &MA) { return isa<MemoryPhi>(MA); });
1433 Defs->insert(DI, *NewAccess);
1434 }
1435 }
1436 } else {
1437 Accesses->push_back(NewAccess);
1438 if (!isa<MemoryUse>(NewAccess)) {
1439 auto *Defs = getOrCreateDefsList(BB);
1440 Defs->push_back(*NewAccess);
1441 }
1442 }
1443 BlockNumberingValid.erase(BB);
1444}
1445
1446void MemorySSA::insertIntoListsBefore(MemoryAccess *What, const BasicBlock *BB,
1447 AccessList::iterator InsertPt) {
1448 auto *Accesses = getWritableBlockAccesses(BB);
1449 bool WasEnd = InsertPt == Accesses->end();
1450 Accesses->insert(AccessList::iterator(InsertPt), What);
1451 if (!isa<MemoryUse>(What)) {
1452 auto *Defs = getOrCreateDefsList(BB);
1453 // If we got asked to insert at the end, we have an easy job, just shove it
1454 // at the end. If we got asked to insert before an existing def, we also get
1455 // an iterator. If we got asked to insert before a use, we have to hunt for
1456 // the next def.
1457 if (WasEnd) {
1458 Defs->push_back(*What);
1459 } else if (isa<MemoryDef>(InsertPt)) {
1460 Defs->insert(InsertPt->getDefsIterator(), *What);
1461 } else {
1462 while (InsertPt != Accesses->end() && !isa<MemoryDef>(InsertPt))
1463 ++InsertPt;
1464 // Either we found a def, or we are inserting at the end
1465 if (InsertPt == Accesses->end())
1466 Defs->push_back(*What);
1467 else
1468 Defs->insert(InsertPt->getDefsIterator(), *What);
1469 }
1470 }
1471 BlockNumberingValid.erase(BB);
1472}
1473
1474// Move What before Where in the IR. The end result is that What will belong to
1475// the right lists and have the right Block set, but will not otherwise be
1476// correct. It will not have the right defining access, and if it is a def,
1477// things below it will not properly be updated.
1478void MemorySSA::moveTo(MemoryUseOrDef *What, BasicBlock *BB,
1479 AccessList::iterator Where) {
1480 // Keep it in the lookup tables, remove from the lists
1481 removeFromLists(What, false);
1482 What->setBlock(BB);
1483 insertIntoListsBefore(What, BB, Where);
1484}
1485
1486void MemorySSA::moveTo(MemoryUseOrDef *What, BasicBlock *BB,
1487 InsertionPlace Point) {
1488 removeFromLists(What, false);
1489 What->setBlock(BB);
1490 insertIntoListsForBlock(What, BB, Point);
1491}
1492
1493MemoryPhi *MemorySSA::createMemoryPhi(BasicBlock *BB) {
1494 assert(!getMemoryAccess(BB) && "MemoryPhi already exists for this BB")(static_cast <bool> (!getMemoryAccess(BB) && "MemoryPhi already exists for this BB"
) ? void (0) : __assert_fail ("!getMemoryAccess(BB) && \"MemoryPhi already exists for this BB\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1494, __extension__ __PRETTY_FUNCTION__))
;
1495 MemoryPhi *Phi = new MemoryPhi(BB->getContext(), BB, NextID++);
1496 // Phi's always are placed at the front of the block.
1497 insertIntoListsForBlock(Phi, BB, Beginning);
1498 ValueToMemoryAccess[BB] = Phi;
1499 return Phi;
1500}
1501
1502MemoryUseOrDef *MemorySSA::createDefinedAccess(Instruction *I,
1503 MemoryAccess *Definition) {
1504 assert(!isa<PHINode>(I) && "Cannot create a defined access for a PHI")(static_cast <bool> (!isa<PHINode>(I) && "Cannot create a defined access for a PHI"
) ? void (0) : __assert_fail ("!isa<PHINode>(I) && \"Cannot create a defined access for a PHI\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1504, __extension__ __PRETTY_FUNCTION__))
;
1505 MemoryUseOrDef *NewAccess = createNewAccess(I);
1506 assert((static_cast <bool> (NewAccess != nullptr && "Tried to create a memory access for a non-memory touching instruction"
) ? void (0) : __assert_fail ("NewAccess != nullptr && \"Tried to create a memory access for a non-memory touching instruction\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1508, __extension__ __PRETTY_FUNCTION__))
1507 NewAccess != nullptr &&(static_cast <bool> (NewAccess != nullptr && "Tried to create a memory access for a non-memory touching instruction"
) ? void (0) : __assert_fail ("NewAccess != nullptr && \"Tried to create a memory access for a non-memory touching instruction\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1508, __extension__ __PRETTY_FUNCTION__))
1508 "Tried to create a memory access for a non-memory touching instruction")(static_cast <bool> (NewAccess != nullptr && "Tried to create a memory access for a non-memory touching instruction"
) ? void (0) : __assert_fail ("NewAccess != nullptr && \"Tried to create a memory access for a non-memory touching instruction\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1508, __extension__ __PRETTY_FUNCTION__))
;
1509 NewAccess->setDefiningAccess(Definition);
1510 return NewAccess;
1511}
1512
1513// Return true if the instruction has ordering constraints.
1514// Note specifically that this only considers stores and loads
1515// because others are still considered ModRef by getModRefInfo.
1516static inline bool isOrdered(const Instruction *I) {
1517 if (auto *SI = dyn_cast<StoreInst>(I)) {
1518 if (!SI->isUnordered())
1519 return true;
1520 } else if (auto *LI = dyn_cast<LoadInst>(I)) {
1521 if (!LI->isUnordered())
1522 return true;
1523 }
1524 return false;
1525}
1526
1527/// \brief Helper function to create new memory accesses
1528MemoryUseOrDef *MemorySSA::createNewAccess(Instruction *I) {
1529 // The assume intrinsic has a control dependency which we model by claiming
1530 // that it writes arbitrarily. Ignore that fake memory dependency here.
1531 // FIXME: Replace this special casing with a more accurate modelling of
1532 // assume's control dependency.
1533 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I))
1534 if (II->getIntrinsicID() == Intrinsic::assume)
1535 return nullptr;
1536
1537 // Find out what affect this instruction has on memory.
1538 ModRefInfo ModRef = AA->getModRefInfo(I, None);
1539 // The isOrdered check is used to ensure that volatiles end up as defs
1540 // (atomics end up as ModRef right now anyway). Until we separate the
1541 // ordering chain from the memory chain, this enables people to see at least
1542 // some relative ordering to volatiles. Note that getClobberingMemoryAccess
1543 // will still give an answer that bypasses other volatile loads. TODO:
1544 // Separate memory aliasing and ordering into two different chains so that we
1545 // can precisely represent both "what memory will this read/write/is clobbered
1546 // by" and "what instructions can I move this past".
1547 bool Def = isModSet(ModRef) || isOrdered(I);
1548 bool Use = isRefSet(ModRef);
1549
1550 // It's possible for an instruction to not modify memory at all. During
1551 // construction, we ignore them.
1552 if (!Def && !Use)
1553 return nullptr;
1554
1555 MemoryUseOrDef *MUD;
1556 if (Def)
1557 MUD = new MemoryDef(I->getContext(), nullptr, I, I->getParent(), NextID++);
1558 else
1559 MUD = new MemoryUse(I->getContext(), nullptr, I, I->getParent());
1560 ValueToMemoryAccess[I] = MUD;
1561 return MUD;
1562}
1563
1564/// \brief Returns true if \p Replacer dominates \p Replacee .
1565bool MemorySSA::dominatesUse(const MemoryAccess *Replacer,
1566 const MemoryAccess *Replacee) const {
1567 if (isa<MemoryUseOrDef>(Replacee))
1568 return DT->dominates(Replacer->getBlock(), Replacee->getBlock());
1569 const auto *MP = cast<MemoryPhi>(Replacee);
1570 // For a phi node, the use occurs in the predecessor block of the phi node.
1571 // Since we may occur multiple times in the phi node, we have to check each
1572 // operand to ensure Replacer dominates each operand where Replacee occurs.
1573 for (const Use &Arg : MP->operands()) {
1574 if (Arg.get() != Replacee &&
1575 !DT->dominates(Replacer->getBlock(), MP->getIncomingBlock(Arg)))
1576 return false;
1577 }
1578 return true;
1579}
1580
1581/// \brief Properly remove \p MA from all of MemorySSA's lookup tables.
1582void MemorySSA::removeFromLookups(MemoryAccess *MA) {
1583 assert(MA->use_empty() &&(static_cast <bool> (MA->use_empty() && "Trying to remove memory access that still has uses"
) ? void (0) : __assert_fail ("MA->use_empty() && \"Trying to remove memory access that still has uses\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1584, __extension__ __PRETTY_FUNCTION__))
1584 "Trying to remove memory access that still has uses")(static_cast <bool> (MA->use_empty() && "Trying to remove memory access that still has uses"
) ? void (0) : __assert_fail ("MA->use_empty() && \"Trying to remove memory access that still has uses\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1584, __extension__ __PRETTY_FUNCTION__))
;
1585 BlockNumbering.erase(MA);
1586 if (MemoryUseOrDef *MUD = dyn_cast<MemoryUseOrDef>(MA))
1587 MUD->setDefiningAccess(nullptr);
1588 // Invalidate our walker's cache if necessary
1589 if (!isa<MemoryUse>(MA))
1590 Walker->invalidateInfo(MA);
1591 // The call below to erase will destroy MA, so we can't change the order we
1592 // are doing things here
1593 Value *MemoryInst;
1594 if (MemoryUseOrDef *MUD = dyn_cast<MemoryUseOrDef>(MA)) {
1595 MemoryInst = MUD->getMemoryInst();
1596 } else {
1597 MemoryInst = MA->getBlock();
1598 }
1599 auto VMA = ValueToMemoryAccess.find(MemoryInst);
1600 if (VMA->second == MA)
1601 ValueToMemoryAccess.erase(VMA);
1602}
1603
1604/// \brief Properly remove \p MA from all of MemorySSA's lists.
1605///
1606/// Because of the way the intrusive list and use lists work, it is important to
1607/// do removal in the right order.
1608/// ShouldDelete defaults to true, and will cause the memory access to also be
1609/// deleted, not just removed.
1610void MemorySSA::removeFromLists(MemoryAccess *MA, bool ShouldDelete) {
1611 // The access list owns the reference, so we erase it from the non-owning list
1612 // first.
1613 if (!isa<MemoryUse>(MA)) {
1614 auto DefsIt = PerBlockDefs.find(MA->getBlock());
1615 std::unique_ptr<DefsList> &Defs = DefsIt->second;
1616 Defs->remove(*MA);
1617 if (Defs->empty())
1618 PerBlockDefs.erase(DefsIt);
1619 }
1620
1621 // The erase call here will delete it. If we don't want it deleted, we call
1622 // remove instead.
1623 auto AccessIt = PerBlockAccesses.find(MA->getBlock());
1624 std::unique_ptr<AccessList> &Accesses = AccessIt->second;
1625 if (ShouldDelete)
1626 Accesses->erase(MA);
1627 else
1628 Accesses->remove(MA);
1629
1630 if (Accesses->empty())
1631 PerBlockAccesses.erase(AccessIt);
1632}
1633
1634void MemorySSA::print(raw_ostream &OS) const {
1635 MemorySSAAnnotatedWriter Writer(this);
1636 F.print(OS, &Writer);
1637}
1638
1639#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1640LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void MemorySSA::dump() const { print(dbgs()); }
1641#endif
1642
1643void MemorySSA::verifyMemorySSA() const {
1644 verifyDefUses(F);
1645 verifyDomination(F);
1646 verifyOrdering(F);
2
Calling 'MemorySSA::verifyOrdering'
1647 Walker->verify(this);
1648}
1649
1650/// \brief Verify that the order and existence of MemoryAccesses matches the
1651/// order and existence of memory affecting instructions.
1652void MemorySSA::verifyOrdering(Function &F) const {
1653 // Walk all the blocks, comparing what the lookups think and what the access
1654 // lists think, as well as the order in the blocks vs the order in the access
1655 // lists.
1656 SmallVector<MemoryAccess *, 32> ActualAccesses;
1657 SmallVector<MemoryAccess *, 32> ActualDefs;
1658 for (BasicBlock &B : F) {
1659 const AccessList *AL = getBlockAccesses(&B);
3
Calling 'MemorySSA::getBlockAccesses'
8
Returning from 'MemorySSA::getBlockAccesses'
9
'AL' initialized here
1660 const auto *DL = getBlockDefs(&B);
1661 MemoryAccess *Phi = getMemoryAccess(&B);
1662 if (Phi) {
10
Taking false branch
1663 ActualAccesses.push_back(Phi);
1664 ActualDefs.push_back(Phi);
1665 }
1666
1667 for (Instruction &I : B) {
1668 MemoryAccess *MA = getMemoryAccess(&I);
1669 assert((!MA || (AL && (isa<MemoryUse>(MA) || DL))) &&(static_cast <bool> ((!MA || (AL && (isa<MemoryUse
>(MA) || DL))) && "We have memory affecting instructions "
"in this block but they are not in the " "access list or defs list"
) ? void (0) : __assert_fail ("(!MA || (AL && (isa<MemoryUse>(MA) || DL))) && \"We have memory affecting instructions \" \"in this block but they are not in the \" \"access list or defs list\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1672, __extension__ __PRETTY_FUNCTION__))
1670 "We have memory affecting instructions "(static_cast <bool> ((!MA || (AL && (isa<MemoryUse
>(MA) || DL))) && "We have memory affecting instructions "
"in this block but they are not in the " "access list or defs list"
) ? void (0) : __assert_fail ("(!MA || (AL && (isa<MemoryUse>(MA) || DL))) && \"We have memory affecting instructions \" \"in this block but they are not in the \" \"access list or defs list\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1672, __extension__ __PRETTY_FUNCTION__))
1671 "in this block but they are not in the "(static_cast <bool> ((!MA || (AL && (isa<MemoryUse
>(MA) || DL))) && "We have memory affecting instructions "
"in this block but they are not in the " "access list or defs list"
) ? void (0) : __assert_fail ("(!MA || (AL && (isa<MemoryUse>(MA) || DL))) && \"We have memory affecting instructions \" \"in this block but they are not in the \" \"access list or defs list\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1672, __extension__ __PRETTY_FUNCTION__))
1672 "access list or defs list")(static_cast <bool> ((!MA || (AL && (isa<MemoryUse
>(MA) || DL))) && "We have memory affecting instructions "
"in this block but they are not in the " "access list or defs list"
) ? void (0) : __assert_fail ("(!MA || (AL && (isa<MemoryUse>(MA) || DL))) && \"We have memory affecting instructions \" \"in this block but they are not in the \" \"access list or defs list\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1672, __extension__ __PRETTY_FUNCTION__))
;
1673 if (MA) {
1674 ActualAccesses.push_back(MA);
1675 if (isa<MemoryDef>(MA))
1676 ActualDefs.push_back(MA);
1677 }
1678 }
1679 // Either we hit the assert, really have no accesses, or we have both
1680 // accesses and an access list.
1681 // Same with defs.
1682 if (!AL && !DL)
11
Assuming 'AL' is null
12
Assuming pointer value is null
13
Assuming 'DL' is non-null
14
Taking false branch
1683 continue;
1684 assert(AL->size() == ActualAccesses.size() &&(static_cast <bool> (AL->size() == ActualAccesses.size
() && "We don't have the same number of accesses in the block as on the "
"access list") ? void (0) : __assert_fail ("AL->size() == ActualAccesses.size() && \"We don't have the same number of accesses in the block as on the \" \"access list\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1686, __extension__ __PRETTY_FUNCTION__))
15
Within the expansion of the macro 'assert':
a
Called C++ object pointer is null
1685 "We don't have the same number of accesses in the block as on the "(static_cast <bool> (AL->size() == ActualAccesses.size
() && "We don't have the same number of accesses in the block as on the "
"access list") ? void (0) : __assert_fail ("AL->size() == ActualAccesses.size() && \"We don't have the same number of accesses in the block as on the \" \"access list\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1686, __extension__ __PRETTY_FUNCTION__))
1686 "access list")(static_cast <bool> (AL->size() == ActualAccesses.size
() && "We don't have the same number of accesses in the block as on the "
"access list") ? void (0) : __assert_fail ("AL->size() == ActualAccesses.size() && \"We don't have the same number of accesses in the block as on the \" \"access list\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1686, __extension__ __PRETTY_FUNCTION__))
;
1687 assert((DL || ActualDefs.size() == 0) &&(static_cast <bool> ((DL || ActualDefs.size() == 0) &&
"Either we should have a defs list, or we should have no defs"
) ? void (0) : __assert_fail ("(DL || ActualDefs.size() == 0) && \"Either we should have a defs list, or we should have no defs\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1688, __extension__ __PRETTY_FUNCTION__))
1688 "Either we should have a defs list, or we should have no defs")(static_cast <bool> ((DL || ActualDefs.size() == 0) &&
"Either we should have a defs list, or we should have no defs"
) ? void (0) : __assert_fail ("(DL || ActualDefs.size() == 0) && \"Either we should have a defs list, or we should have no defs\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1688, __extension__ __PRETTY_FUNCTION__))
;
1689 assert((!DL || DL->size() == ActualDefs.size()) &&(static_cast <bool> ((!DL || DL->size() == ActualDefs
.size()) && "We don't have the same number of defs in the block as on the "
"def list") ? void (0) : __assert_fail ("(!DL || DL->size() == ActualDefs.size()) && \"We don't have the same number of defs in the block as on the \" \"def list\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1691, __extension__ __PRETTY_FUNCTION__))
1690 "We don't have the same number of defs in the block as on the "(static_cast <bool> ((!DL || DL->size() == ActualDefs
.size()) && "We don't have the same number of defs in the block as on the "
"def list") ? void (0) : __assert_fail ("(!DL || DL->size() == ActualDefs.size()) && \"We don't have the same number of defs in the block as on the \" \"def list\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1691, __extension__ __PRETTY_FUNCTION__))
1691 "def list")(static_cast <bool> ((!DL || DL->size() == ActualDefs
.size()) && "We don't have the same number of defs in the block as on the "
"def list") ? void (0) : __assert_fail ("(!DL || DL->size() == ActualDefs.size()) && \"We don't have the same number of defs in the block as on the \" \"def list\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1691, __extension__ __PRETTY_FUNCTION__))
;
1692 auto ALI = AL->begin();
1693 auto AAI = ActualAccesses.begin();
1694 while (ALI != AL->end() && AAI != ActualAccesses.end()) {
1695 assert(&*ALI == *AAI && "Not the same accesses in the same order")(static_cast <bool> (&*ALI == *AAI && "Not the same accesses in the same order"
) ? void (0) : __assert_fail ("&*ALI == *AAI && \"Not the same accesses in the same order\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1695, __extension__ __PRETTY_FUNCTION__))
;
1696 ++ALI;
1697 ++AAI;
1698 }
1699 ActualAccesses.clear();
1700 if (DL) {
1701 auto DLI = DL->begin();
1702 auto ADI = ActualDefs.begin();
1703 while (DLI != DL->end() && ADI != ActualDefs.end()) {
1704 assert(&*DLI == *ADI && "Not the same defs in the same order")(static_cast <bool> (&*DLI == *ADI && "Not the same defs in the same order"
) ? void (0) : __assert_fail ("&*DLI == *ADI && \"Not the same defs in the same order\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1704, __extension__ __PRETTY_FUNCTION__))
;
1705 ++DLI;
1706 ++ADI;
1707 }
1708 }
1709 ActualDefs.clear();
1710 }
1711}
1712
1713/// \brief Verify the domination properties of MemorySSA by checking that each
1714/// definition dominates all of its uses.
1715void MemorySSA::verifyDomination(Function &F) const {
1716#ifndef NDEBUG
1717 for (BasicBlock &B : F) {
1718 // Phi nodes are attached to basic blocks
1719 if (MemoryPhi *MP = getMemoryAccess(&B))
1720 for (const Use &U : MP->uses())
1721 assert(dominates(MP, U) && "Memory PHI does not dominate it's uses")(static_cast <bool> (dominates(MP, U) && "Memory PHI does not dominate it's uses"
) ? void (0) : __assert_fail ("dominates(MP, U) && \"Memory PHI does not dominate it's uses\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1721, __extension__ __PRETTY_FUNCTION__))
;
1722
1723 for (Instruction &I : B) {
1724 MemoryAccess *MD = dyn_cast_or_null<MemoryDef>(getMemoryAccess(&I));
1725 if (!MD)
1726 continue;
1727
1728 for (const Use &U : MD->uses())
1729 assert(dominates(MD, U) && "Memory Def does not dominate it's uses")(static_cast <bool> (dominates(MD, U) && "Memory Def does not dominate it's uses"
) ? void (0) : __assert_fail ("dominates(MD, U) && \"Memory Def does not dominate it's uses\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1729, __extension__ __PRETTY_FUNCTION__))
;
1730 }
1731 }
1732#endif
1733}
1734
1735/// \brief Verify the def-use lists in MemorySSA, by verifying that \p Use
1736/// appears in the use list of \p Def.
1737void MemorySSA::verifyUseInDefs(MemoryAccess *Def, MemoryAccess *Use) const {
1738#ifndef NDEBUG
1739 // The live on entry use may cause us to get a NULL def here
1740 if (!Def)
1741 assert(isLiveOnEntryDef(Use) &&(static_cast <bool> (isLiveOnEntryDef(Use) && "Null def but use not point to live on entry def"
) ? void (0) : __assert_fail ("isLiveOnEntryDef(Use) && \"Null def but use not point to live on entry def\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1742, __extension__ __PRETTY_FUNCTION__))
1742 "Null def but use not point to live on entry def")(static_cast <bool> (isLiveOnEntryDef(Use) && "Null def but use not point to live on entry def"
) ? void (0) : __assert_fail ("isLiveOnEntryDef(Use) && \"Null def but use not point to live on entry def\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1742, __extension__ __PRETTY_FUNCTION__))
;
1743 else
1744 assert(is_contained(Def->users(), Use) &&(static_cast <bool> (is_contained(Def->users(), Use)
&& "Did not find use in def's use list") ? void (0) :
__assert_fail ("is_contained(Def->users(), Use) && \"Did not find use in def's use list\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1745, __extension__ __PRETTY_FUNCTION__))
1745 "Did not find use in def's use list")(static_cast <bool> (is_contained(Def->users(), Use)
&& "Did not find use in def's use list") ? void (0) :
__assert_fail ("is_contained(Def->users(), Use) && \"Did not find use in def's use list\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1745, __extension__ __PRETTY_FUNCTION__))
;
1746#endif
1747}
1748
1749/// \brief Verify the immediate use information, by walking all the memory
1750/// accesses and verifying that, for each use, it appears in the
1751/// appropriate def's use list
1752void MemorySSA::verifyDefUses(Function &F) const {
1753 for (BasicBlock &B : F) {
1754 // Phi nodes are attached to basic blocks
1755 if (MemoryPhi *Phi = getMemoryAccess(&B)) {
1756 assert(Phi->getNumOperands() == static_cast<unsigned>(std::distance((static_cast <bool> (Phi->getNumOperands() == static_cast
<unsigned>(std::distance( pred_begin(&B), pred_end(
&B))) && "Incomplete MemoryPhi Node") ? void (0) :
__assert_fail ("Phi->getNumOperands() == static_cast<unsigned>(std::distance( pred_begin(&B), pred_end(&B))) && \"Incomplete MemoryPhi Node\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1758, __extension__ __PRETTY_FUNCTION__))
1757 pred_begin(&B), pred_end(&B))) &&(static_cast <bool> (Phi->getNumOperands() == static_cast
<unsigned>(std::distance( pred_begin(&B), pred_end(
&B))) && "Incomplete MemoryPhi Node") ? void (0) :
__assert_fail ("Phi->getNumOperands() == static_cast<unsigned>(std::distance( pred_begin(&B), pred_end(&B))) && \"Incomplete MemoryPhi Node\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1758, __extension__ __PRETTY_FUNCTION__))
1758 "Incomplete MemoryPhi Node")(static_cast <bool> (Phi->getNumOperands() == static_cast
<unsigned>(std::distance( pred_begin(&B), pred_end(
&B))) && "Incomplete MemoryPhi Node") ? void (0) :
__assert_fail ("Phi->getNumOperands() == static_cast<unsigned>(std::distance( pred_begin(&B), pred_end(&B))) && \"Incomplete MemoryPhi Node\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1758, __extension__ __PRETTY_FUNCTION__))
;
1759 for (unsigned I = 0, E = Phi->getNumIncomingValues(); I != E; ++I)
1760 verifyUseInDefs(Phi->getIncomingValue(I), Phi);
1761 }
1762
1763 for (Instruction &I : B) {
1764 if (MemoryUseOrDef *MA = getMemoryAccess(&I)) {
1765 verifyUseInDefs(MA->getDefiningAccess(), MA);
1766 }
1767 }
1768 }
1769}
1770
1771MemoryUseOrDef *MemorySSA::getMemoryAccess(const Instruction *I) const {
1772 return cast_or_null<MemoryUseOrDef>(ValueToMemoryAccess.lookup(I));
1773}
1774
1775MemoryPhi *MemorySSA::getMemoryAccess(const BasicBlock *BB) const {
1776 return cast_or_null<MemoryPhi>(ValueToMemoryAccess.lookup(cast<Value>(BB)));
1777}
1778
1779/// Perform a local numbering on blocks so that instruction ordering can be
1780/// determined in constant time.
1781/// TODO: We currently just number in order. If we numbered by N, we could
1782/// allow at least N-1 sequences of insertBefore or insertAfter (and at least
1783/// log2(N) sequences of mixed before and after) without needing to invalidate
1784/// the numbering.
1785void MemorySSA::renumberBlock(const BasicBlock *B) const {
1786 // The pre-increment ensures the numbers really start at 1.
1787 unsigned long CurrentNumber = 0;
1788 const AccessList *AL = getBlockAccesses(B);
1789 assert(AL != nullptr && "Asking to renumber an empty block")(static_cast <bool> (AL != nullptr && "Asking to renumber an empty block"
) ? void (0) : __assert_fail ("AL != nullptr && \"Asking to renumber an empty block\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1789, __extension__ __PRETTY_FUNCTION__))
;
1790 for (const auto &I : *AL)
1791 BlockNumbering[&I] = ++CurrentNumber;
1792 BlockNumberingValid.insert(B);
1793}
1794
1795/// \brief Determine, for two memory accesses in the same block,
1796/// whether \p Dominator dominates \p Dominatee.
1797/// \returns True if \p Dominator dominates \p Dominatee.
1798bool MemorySSA::locallyDominates(const MemoryAccess *Dominator,
1799 const MemoryAccess *Dominatee) const {
1800 const BasicBlock *DominatorBlock = Dominator->getBlock();
1801
1802 assert((DominatorBlock == Dominatee->getBlock()) &&(static_cast <bool> ((DominatorBlock == Dominatee->getBlock
()) && "Asking for local domination when accesses are in different blocks!"
) ? void (0) : __assert_fail ("(DominatorBlock == Dominatee->getBlock()) && \"Asking for local domination when accesses are in different blocks!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1803, __extension__ __PRETTY_FUNCTION__))
1803 "Asking for local domination when accesses are in different blocks!")(static_cast <bool> ((DominatorBlock == Dominatee->getBlock
()) && "Asking for local domination when accesses are in different blocks!"
) ? void (0) : __assert_fail ("(DominatorBlock == Dominatee->getBlock()) && \"Asking for local domination when accesses are in different blocks!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1803, __extension__ __PRETTY_FUNCTION__))
;
1804 // A node dominates itself.
1805 if (Dominatee == Dominator)
1806 return true;
1807
1808 // When Dominatee is defined on function entry, it is not dominated by another
1809 // memory access.
1810 if (isLiveOnEntryDef(Dominatee))
1811 return false;
1812
1813 // When Dominator is defined on function entry, it dominates the other memory
1814 // access.
1815 if (isLiveOnEntryDef(Dominator))
1816 return true;
1817
1818 if (!BlockNumberingValid.count(DominatorBlock))
1819 renumberBlock(DominatorBlock);
1820
1821 unsigned long DominatorNum = BlockNumbering.lookup(Dominator);
1822 // All numbers start with 1
1823 assert(DominatorNum != 0 && "Block was not numbered properly")(static_cast <bool> (DominatorNum != 0 && "Block was not numbered properly"
) ? void (0) : __assert_fail ("DominatorNum != 0 && \"Block was not numbered properly\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1823, __extension__ __PRETTY_FUNCTION__))
;
1824 unsigned long DominateeNum = BlockNumbering.lookup(Dominatee);
1825 assert(DominateeNum != 0 && "Block was not numbered properly")(static_cast <bool> (DominateeNum != 0 && "Block was not numbered properly"
) ? void (0) : __assert_fail ("DominateeNum != 0 && \"Block was not numbered properly\""
, "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1825, __extension__ __PRETTY_FUNCTION__))
;
1826 return DominatorNum < DominateeNum;
1827}
1828
1829bool MemorySSA::dominates(const MemoryAccess *Dominator,
1830 const MemoryAccess *Dominatee) const {
1831 if (Dominator == Dominatee)
1832 return true;
1833
1834 if (isLiveOnEntryDef(Dominatee))
1835 return false;
1836
1837 if (Dominator->getBlock() != Dominatee->getBlock())
1838 return DT->dominates(Dominator->getBlock(), Dominatee->getBlock());
1839 return locallyDominates(Dominator, Dominatee);
1840}
1841
1842bool MemorySSA::dominates(const MemoryAccess *Dominator,
1843 const Use &Dominatee) const {
1844 if (MemoryPhi *MP = dyn_cast<MemoryPhi>(Dominatee.getUser())) {
1845 BasicBlock *UseBB = MP->getIncomingBlock(Dominatee);
1846 // The def must dominate the incoming block of the phi.
1847 if (UseBB != Dominator->getBlock())
1848 return DT->dominates(Dominator->getBlock(), UseBB);
1849 // If the UseBB and the DefBB are the same, compare locally.
1850 return locallyDominates(Dominator, cast<MemoryAccess>(Dominatee));
1851 }
1852 // If it's not a PHI node use, the normal dominates can already handle it.
1853 return dominates(Dominator, cast<MemoryAccess>(Dominatee.getUser()));
1854}
1855
1856const static char LiveOnEntryStr[] = "liveOnEntry";
1857
1858void MemoryAccess::print(raw_ostream &OS) const {
1859 switch (getValueID()) {
1860 case MemoryPhiVal: return static_cast<const MemoryPhi *>(this)->print(OS);
1861 case MemoryDefVal: return static_cast<const MemoryDef *>(this)->print(OS);
1862 case MemoryUseVal: return static_cast<const MemoryUse *>(this)->print(OS);
1863 }
1864 llvm_unreachable("invalid value id")::llvm::llvm_unreachable_internal("invalid value id", "/build/llvm-toolchain-snapshot-7~svn329677/lib/Analysis/MemorySSA.cpp"
, 1864)
;
1865}
1866
1867void MemoryDef::print(raw_ostream &OS) const {
1868 MemoryAccess *UO = getDefiningAccess();
1869
1870 OS << getID() << " = MemoryDef(";
1871 if (UO && UO->getID())
1872 OS << UO->getID();
1873 else
1874 OS << LiveOnEntryStr;
1875 OS << ')';
1876}
1877
1878void MemoryPhi::print(raw_ostream &OS) const {
1879 bool First = true;
1880 OS << getID() << " = MemoryPhi(";
1881 for (const auto &Op : operands()) {
1882 BasicBlock *BB = getIncomingBlock(Op);
1883 MemoryAccess *MA = cast<MemoryAccess>(Op);
1884 if (!First)
1885 OS << ',';
1886 else
1887 First = false;
1888
1889 OS << '{';
1890 if (BB->hasName())
1891 OS << BB->getName();
1892 else
1893 BB->printAsOperand(OS, false);
1894 OS << ',';
1895 if (unsigned ID = MA->getID())
1896 OS << ID;
1897 else
1898 OS << LiveOnEntryStr;
1899 OS << '}';
1900 }
1901 OS << ')';
1902}
1903
1904void MemoryUse::print(raw_ostream &OS) const {
1905 MemoryAccess *UO = getDefiningAccess();
1906 OS << "MemoryUse(";
1907 if (UO && UO->getID())
1908 OS << UO->getID();
1909 else
1910 OS << LiveOnEntryStr;
1911 OS << ')';
1912}
1913
1914void MemoryAccess::dump() const {
1915// Cannot completely remove virtual function even in release mode.
1916#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1917 print(dbgs());
1918 dbgs() << "\n";
1919#endif
1920}
1921
1922char MemorySSAPrinterLegacyPass::ID = 0;
1923
1924MemorySSAPrinterLegacyPass::MemorySSAPrinterLegacyPass() : FunctionPass(ID) {
1925 initializeMemorySSAPrinterLegacyPassPass(*PassRegistry::getPassRegistry());
1926}
1927
1928void MemorySSAPrinterLegacyPass::getAnalysisUsage(AnalysisUsage &AU) const {
1929 AU.setPreservesAll();
1930 AU.addRequired<MemorySSAWrapperPass>();
1931}
1932
1933bool MemorySSAPrinterLegacyPass::runOnFunction(Function &F) {
1934 auto &MSSA = getAnalysis<MemorySSAWrapperPass>().getMSSA();
1935 MSSA.print(dbgs());
1936 if (VerifyMemorySSA)
1937 MSSA.verifyMemorySSA();
1938 return false;
1939}
1940
1941AnalysisKey MemorySSAAnalysis::Key;
1942
1943MemorySSAAnalysis::Result MemorySSAAnalysis::run(Function &F,
1944 FunctionAnalysisManager &AM) {
1945 auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
1946 auto &AA = AM.getResult<AAManager>(F);
1947 return MemorySSAAnalysis::Result(llvm::make_unique<MemorySSA>(F, &AA, &DT));
1948}
1949
1950PreservedAnalyses MemorySSAPrinterPass::run(Function &F,
1951 FunctionAnalysisManager &AM) {
1952 OS << "MemorySSA for function: " << F.getName() << "\n";
1953 AM.getResult<MemorySSAAnalysis>(F).getMSSA().print(OS);
1954
1955 return PreservedAnalyses::all();
1956}
1957
1958PreservedAnalyses MemorySSAVerifierPass::run(Function &F,
1959 FunctionAnalysisManager &AM) {
1960 AM.getResult<MemorySSAAnalysis>(F).getMSSA().verifyMemorySSA();
1961
1962 return PreservedAnalyses::all();
1963}
1964
1965char MemorySSAWrapperPass::ID = 0;
1966
1967MemorySSAWrapperPass::MemorySSAWrapperPass() : FunctionPass(ID) {
1968 initializeMemorySSAWrapperPassPass(*PassRegistry::getPassRegistry());
1969}
1970
1971void MemorySSAWrapperPass::releaseMemory() { MSSA.reset(); }
1972
1973void MemorySSAWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
1974 AU.setPreservesAll();
1975 AU.addRequiredTransitive<DominatorTreeWrapperPass>();
1976 AU.addRequiredTransitive<AAResultsWrapperPass>();
1977}
1978
1979bool MemorySSAWrapperPass::runOnFunction(Function &F) {
1980 auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
1981 auto &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
1982 MSSA.reset(new MemorySSA(F, &AA, &DT));
1983 return false;
1984}
1985
1986void MemorySSAWrapperPass::verifyAnalysis() const { MSSA->verifyMemorySSA(); }
1
Calling 'MemorySSA::verifyMemorySSA'
1987
1988void MemorySSAWrapperPass::print(raw_ostream &OS, const Module *M) const {
1989 MSSA->print(OS);
1990}
1991
1992MemorySSAWalker::MemorySSAWalker(MemorySSA *M) : MSSA(M) {}
1993
1994MemorySSA::CachingWalker::CachingWalker(MemorySSA *M, AliasAnalysis *A,
1995 DominatorTree *D)
1996 : MemorySSAWalker(M), Walker(*M, *A, *D) {}
1997
1998void MemorySSA::CachingWalker::invalidateInfo(MemoryAccess *MA) {
1999 if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA))
2000 MUD->resetOptimized();
2001}
2002
2003/// \brief Walk the use-def chains starting at \p MA and find
2004/// the MemoryAccess that actually clobbers Loc.
2005///
2006/// \returns our clobbering memory access
2007MemoryAccess *MemorySSA::CachingWalker::getClobberingMemoryAccess(
2008 MemoryAccess *StartingAccess, UpwardsMemoryQuery &Q) {
2009 return Walker.findClobber(StartingAccess, Q);
2010}
2011
2012MemoryAccess *MemorySSA::CachingWalker::getClobberingMemoryAccess(
2013 MemoryAccess *StartingAccess, const MemoryLocation &Loc) {
2014 if (isa<MemoryPhi>(StartingAccess))
2015 return StartingAccess;
2016
2017 auto *StartingUseOrDef = cast<MemoryUseOrDef>(StartingAccess);
2018 if (MSSA->isLiveOnEntryDef(StartingUseOrDef))
2019 return StartingUseOrDef;
2020
2021 Instruction *I = StartingUseOrDef->getMemoryInst();
2022
2023 // Conservatively, fences are always clobbers, so don't perform the walk if we
2024 // hit a fence.
2025 if (!ImmutableCallSite(I) && I->isFenceLike())
2026 return StartingUseOrDef;
2027
2028 UpwardsMemoryQuery Q;
2029 Q.OriginalAccess = StartingUseOrDef;
2030 Q.StartingLoc = Loc;
2031 Q.Inst = I;
2032 Q.IsCall = false;
2033
2034 // Unlike the other function, do not walk to the def of a def, because we are
2035 // handed something we already believe is the clobbering access.
2036 MemoryAccess *DefiningAccess = isa<MemoryUse>(StartingUseOrDef)
2037 ? StartingUseOrDef->getDefiningAccess()
2038 : StartingUseOrDef;
2039
2040 MemoryAccess *Clobber = getClobberingMemoryAccess(DefiningAccess, Q);
2041 DEBUG(dbgs() << "Starting Memory SSA clobber for " << *I << " is ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "Starting Memory SSA clobber for "
<< *I << " is "; } } while (false)
;
2042 DEBUG(dbgs() << *StartingUseOrDef << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << *StartingUseOrDef << "\n"
; } } while (false)
;
2043 DEBUG(dbgs() << "Final Memory SSA clobber for " << *I << " is ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "Final Memory SSA clobber for "
<< *I << " is "; } } while (false)
;
2044 DEBUG(dbgs() << *Clobber << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << *Clobber << "\n"; } } while
(false)
;
2045 return Clobber;
2046}
2047
2048MemoryAccess *
2049MemorySSA::CachingWalker::getClobberingMemoryAccess(MemoryAccess *MA) {
2050 auto *StartingAccess = dyn_cast<MemoryUseOrDef>(MA);
2051 // If this is a MemoryPhi, we can't do anything.
2052 if (!StartingAccess)
2053 return MA;
2054
2055 // If this is an already optimized use or def, return the optimized result.
2056 // Note: Currently, we store the optimized def result in a separate field,
2057 // since we can't use the defining access.
2058 if (StartingAccess->isOptimized())
2059 return StartingAccess->getOptimized();
2060
2061 const Instruction *I = StartingAccess->getMemoryInst();
2062 UpwardsMemoryQuery Q(I, StartingAccess);
2063 // We can't sanely do anything with a fence, since they conservatively clobber
2064 // all memory, and have no locations to get pointers from to try to
2065 // disambiguate.
2066 if (!Q.IsCall && I->isFenceLike())
2067 return StartingAccess;
2068
2069 if (isUseTriviallyOptimizableToLiveOnEntry(*MSSA->AA, I)) {
2070 MemoryAccess *LiveOnEntry = MSSA->getLiveOnEntryDef();
2071 StartingAccess->setOptimized(LiveOnEntry);
2072 StartingAccess->setOptimizedAccessType(None);
2073 return LiveOnEntry;
2074 }
2075
2076 // Start with the thing we already think clobbers this location
2077 MemoryAccess *DefiningAccess = StartingAccess->getDefiningAccess();
2078
2079 // At this point, DefiningAccess may be the live on entry def.
2080 // If it is, we will not get a better result.
2081 if (MSSA->isLiveOnEntryDef(DefiningAccess)) {
2082 StartingAccess->setOptimized(DefiningAccess);
2083 StartingAccess->setOptimizedAccessType(None);
2084 return DefiningAccess;
2085 }
2086
2087 MemoryAccess *Result = getClobberingMemoryAccess(DefiningAccess, Q);
2088 DEBUG(dbgs() << "Starting Memory SSA clobber for " << *I << " is ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "Starting Memory SSA clobber for "
<< *I << " is "; } } while (false)
;
2089 DEBUG(dbgs() << *DefiningAccess << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << *DefiningAccess << "\n"
; } } while (false)
;
2090 DEBUG(dbgs() << "Final Memory SSA clobber for " << *I << " is ")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << "Final Memory SSA clobber for "
<< *I << " is "; } } while (false)
;
2091 DEBUG(dbgs() << *Result << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << *Result << "\n"; } } while
(false)
;
2092
2093 StartingAccess->setOptimized(Result);
2094 if (MSSA->isLiveOnEntryDef(Result))
2095 StartingAccess->setOptimizedAccessType(None);
2096 else if (Q.AR == MustAlias)
2097 StartingAccess->setOptimizedAccessType(MustAlias);
2098
2099 return Result;
2100}
2101
2102MemoryAccess *
2103DoNothingMemorySSAWalker::getClobberingMemoryAccess(MemoryAccess *MA) {
2104 if (auto *Use = dyn_cast<MemoryUseOrDef>(MA))
2105 return Use->getDefiningAccess();
2106 return MA;
2107}
2108
2109MemoryAccess *DoNothingMemorySSAWalker::getClobberingMemoryAccess(
2110 MemoryAccess *StartingAccess, const MemoryLocation &) {
2111 if (auto *Use = dyn_cast<MemoryUseOrDef>(StartingAccess))
2112 return Use->getDefiningAccess();
2113 return StartingAccess;
2114}
2115
2116void MemoryPhi::deleteMe(DerivedUser *Self) {
2117 delete static_cast<MemoryPhi *>(Self);
2118}
2119
2120void MemoryDef::deleteMe(DerivedUser *Self) {
2121 delete static_cast<MemoryDef *>(Self);
2122}
2123
2124void MemoryUse::deleteMe(DerivedUser *Self) {
2125 delete static_cast<MemoryUse *>(Self);
2126}

/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h

1//===- MemorySSA.h - Build Memory SSA ---------------------------*- 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/// \file
11/// \brief This file exposes an interface to building/using memory SSA to
12/// walk memory instructions using a use/def graph.
13///
14/// Memory SSA class builds an SSA form that links together memory access
15/// instructions such as loads, stores, atomics, and calls. Additionally, it
16/// does a trivial form of "heap versioning" Every time the memory state changes
17/// in the program, we generate a new heap version. It generates
18/// MemoryDef/Uses/Phis that are overlayed on top of the existing instructions.
19///
20/// As a trivial example,
21/// define i32 @main() #0 {
22/// entry:
23/// %call = call noalias i8* @_Znwm(i64 4) #2
24/// %0 = bitcast i8* %call to i32*
25/// %call1 = call noalias i8* @_Znwm(i64 4) #2
26/// %1 = bitcast i8* %call1 to i32*
27/// store i32 5, i32* %0, align 4
28/// store i32 7, i32* %1, align 4
29/// %2 = load i32* %0, align 4
30/// %3 = load i32* %1, align 4
31/// %add = add nsw i32 %2, %3
32/// ret i32 %add
33/// }
34///
35/// Will become
36/// define i32 @main() #0 {
37/// entry:
38/// ; 1 = MemoryDef(0)
39/// %call = call noalias i8* @_Znwm(i64 4) #3
40/// %2 = bitcast i8* %call to i32*
41/// ; 2 = MemoryDef(1)
42/// %call1 = call noalias i8* @_Znwm(i64 4) #3
43/// %4 = bitcast i8* %call1 to i32*
44/// ; 3 = MemoryDef(2)
45/// store i32 5, i32* %2, align 4
46/// ; 4 = MemoryDef(3)
47/// store i32 7, i32* %4, align 4
48/// ; MemoryUse(3)
49/// %7 = load i32* %2, align 4
50/// ; MemoryUse(4)
51/// %8 = load i32* %4, align 4
52/// %add = add nsw i32 %7, %8
53/// ret i32 %add
54/// }
55///
56/// Given this form, all the stores that could ever effect the load at %8 can be
57/// gotten by using the MemoryUse associated with it, and walking from use to
58/// def until you hit the top of the function.
59///
60/// Each def also has a list of users associated with it, so you can walk from
61/// both def to users, and users to defs. Note that we disambiguate MemoryUses,
62/// but not the RHS of MemoryDefs. You can see this above at %7, which would
63/// otherwise be a MemoryUse(4). Being disambiguated means that for a given
64/// store, all the MemoryUses on its use lists are may-aliases of that store
65/// (but the MemoryDefs on its use list may not be).
66///
67/// MemoryDefs are not disambiguated because it would require multiple reaching
68/// definitions, which would require multiple phis, and multiple memoryaccesses
69/// per instruction.
70//
71//===----------------------------------------------------------------------===//
72
73#ifndef LLVM_ANALYSIS_MEMORYSSA_H
74#define LLVM_ANALYSIS_MEMORYSSA_H
75
76#include "llvm/ADT/DenseMap.h"
77#include "llvm/ADT/GraphTraits.h"
78#include "llvm/ADT/SmallPtrSet.h"
79#include "llvm/ADT/SmallVector.h"
80#include "llvm/ADT/ilist.h"
81#include "llvm/ADT/ilist_node.h"
82#include "llvm/ADT/iterator.h"
83#include "llvm/ADT/iterator_range.h"
84#include "llvm/ADT/simple_ilist.h"
85#include "llvm/Analysis/AliasAnalysis.h"
86#include "llvm/Analysis/MemoryLocation.h"
87#include "llvm/Analysis/PHITransAddr.h"
88#include "llvm/IR/BasicBlock.h"
89#include "llvm/IR/DerivedUser.h"
90#include "llvm/IR/Dominators.h"
91#include "llvm/IR/Module.h"
92#include "llvm/IR/Type.h"
93#include "llvm/IR/Use.h"
94#include "llvm/IR/User.h"
95#include "llvm/IR/Value.h"
96#include "llvm/IR/ValueHandle.h"
97#include "llvm/Pass.h"
98#include "llvm/Support/Casting.h"
99#include <algorithm>
100#include <cassert>
101#include <cstddef>
102#include <iterator>
103#include <memory>
104#include <utility>
105
106namespace llvm {
107
108class Function;
109class Instruction;
110class MemoryAccess;
111class MemorySSAWalker;
112class LLVMContext;
113class raw_ostream;
114
115namespace MSSAHelpers {
116
117struct AllAccessTag {};
118struct DefsOnlyTag {};
119
120} // end namespace MSSAHelpers
121
122enum : unsigned {
123 // Used to signify what the default invalid ID is for MemoryAccess's
124 // getID()
125 INVALID_MEMORYACCESS_ID = -1U
126};
127
128template <class T> class memoryaccess_def_iterator_base;
129using memoryaccess_def_iterator = memoryaccess_def_iterator_base<MemoryAccess>;
130using const_memoryaccess_def_iterator =
131 memoryaccess_def_iterator_base<const MemoryAccess>;
132
133// \brief The base for all memory accesses. All memory accesses in a block are
134// linked together using an intrusive list.
135class MemoryAccess
136 : public DerivedUser,
137 public ilist_node<MemoryAccess, ilist_tag<MSSAHelpers::AllAccessTag>>,
138 public ilist_node<MemoryAccess, ilist_tag<MSSAHelpers::DefsOnlyTag>> {
139public:
140 using AllAccessType =
141 ilist_node<MemoryAccess, ilist_tag<MSSAHelpers::AllAccessTag>>;
142 using DefsOnlyType =
143 ilist_node<MemoryAccess, ilist_tag<MSSAHelpers::DefsOnlyTag>>;
144
145 MemoryAccess(const MemoryAccess &) = delete;
146 MemoryAccess &operator=(const MemoryAccess &) = delete;
147
148 void *operator new(size_t) = delete;
149
150 // Methods for support type inquiry through isa, cast, and
151 // dyn_cast
152 static bool classof(const Value *V) {
153 unsigned ID = V->getValueID();
154 return ID == MemoryUseVal || ID == MemoryPhiVal || ID == MemoryDefVal;
155 }
156
157 BasicBlock *getBlock() const { return Block; }
158
159 void print(raw_ostream &OS) const;
160 void dump() const;
161
162 /// \brief The user iterators for a memory access
163 using iterator = user_iterator;
164 using const_iterator = const_user_iterator;
165
166 /// \brief This iterator walks over all of the defs in a given
167 /// MemoryAccess. For MemoryPhi nodes, this walks arguments. For
168 /// MemoryUse/MemoryDef, this walks the defining access.
169 memoryaccess_def_iterator defs_begin();
170 const_memoryaccess_def_iterator defs_begin() const;
171 memoryaccess_def_iterator defs_end();
172 const_memoryaccess_def_iterator defs_end() const;
173
174 /// \brief Get the iterators for the all access list and the defs only list
175 /// We default to the all access list.
176 AllAccessType::self_iterator getIterator() {
177 return this->AllAccessType::getIterator();
178 }
179 AllAccessType::const_self_iterator getIterator() const {
180 return this->AllAccessType::getIterator();
181 }
182 AllAccessType::reverse_self_iterator getReverseIterator() {
183 return this->AllAccessType::getReverseIterator();
184 }
185 AllAccessType::const_reverse_self_iterator getReverseIterator() const {
186 return this->AllAccessType::getReverseIterator();
187 }
188 DefsOnlyType::self_iterator getDefsIterator() {
189 return this->DefsOnlyType::getIterator();
190 }
191 DefsOnlyType::const_self_iterator getDefsIterator() const {
192 return this->DefsOnlyType::getIterator();
193 }
194 DefsOnlyType::reverse_self_iterator getReverseDefsIterator() {
195 return this->DefsOnlyType::getReverseIterator();
196 }
197 DefsOnlyType::const_reverse_self_iterator getReverseDefsIterator() const {
198 return this->DefsOnlyType::getReverseIterator();
199 }
200
201protected:
202 friend class MemoryDef;
203 friend class MemoryPhi;
204 friend class MemorySSA;
205 friend class MemoryUse;
206 friend class MemoryUseOrDef;
207
208 /// \brief Used by MemorySSA to change the block of a MemoryAccess when it is
209 /// moved.
210 void setBlock(BasicBlock *BB) { Block = BB; }
211
212 /// \brief Used for debugging and tracking things about MemoryAccesses.
213 /// Guaranteed unique among MemoryAccesses, no guarantees otherwise.
214 inline unsigned getID() const;
215
216 MemoryAccess(LLVMContext &C, unsigned Vty, DeleteValueTy DeleteValue,
217 BasicBlock *BB, unsigned NumOperands)
218 : DerivedUser(Type::getVoidTy(C), Vty, nullptr, NumOperands, DeleteValue),
219 Block(BB) {}
220
221 // Use deleteValue() to delete a generic MemoryAccess.
222 ~MemoryAccess() = default;
223
224private:
225 BasicBlock *Block;
226};
227
228template <>
229struct ilist_alloc_traits<MemoryAccess> {
230 static void deleteNode(MemoryAccess *MA) { MA->deleteValue(); }
231};
232
233inline raw_ostream &operator<<(raw_ostream &OS, const MemoryAccess &MA) {
234 MA.print(OS);
235 return OS;
236}
237
238/// \brief Class that has the common methods + fields of memory uses/defs. It's
239/// a little awkward to have, but there are many cases where we want either a
240/// use or def, and there are many cases where uses are needed (defs aren't
241/// acceptable), and vice-versa.
242///
243/// This class should never be instantiated directly; make a MemoryUse or
244/// MemoryDef instead.
245class MemoryUseOrDef : public MemoryAccess {
246public:
247 void *operator new(size_t) = delete;
248
249 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(MemoryAccess)public: inline MemoryAccess *getOperand(unsigned) const; inline
void setOperand(unsigned, MemoryAccess*); inline op_iterator
op_begin(); inline const_op_iterator op_begin() const; inline
op_iterator op_end(); inline const_op_iterator op_end() const
; protected: template <int> inline Use &Op(); template
<int> inline const Use &Op() const; public: inline
unsigned getNumOperands() const
;
250
251 /// \brief Get the instruction that this MemoryUse represents.
252 Instruction *getMemoryInst() const { return MemoryInstruction; }
253
254 /// \brief Get the access that produces the memory state used by this Use.
255 MemoryAccess *getDefiningAccess() const { return getOperand(0); }
256
257 static bool classof(const Value *MA) {
258 return MA->getValueID() == MemoryUseVal || MA->getValueID() == MemoryDefVal;
259 }
260
261 // Sadly, these have to be public because they are needed in some of the
262 // iterators.
263 inline bool isOptimized() const;
264 inline MemoryAccess *getOptimized() const;
265 inline void setOptimized(MemoryAccess *);
266
267 // Retrieve AliasResult type of the optimized access. Ideally this would be
268 // returned by the caching walker and may go away in the future.
269 Optional<AliasResult> getOptimizedAccessType() const {
270 return OptimizedAccessAlias;
271 }
272
273 /// \brief Reset the ID of what this MemoryUse was optimized to, causing it to
274 /// be rewalked by the walker if necessary.
275 /// This really should only be called by tests.
276 inline void resetOptimized();
277
278protected:
279 friend class MemorySSA;
280 friend class MemorySSAUpdater;
281
282 MemoryUseOrDef(LLVMContext &C, MemoryAccess *DMA, unsigned Vty,
283 DeleteValueTy DeleteValue, Instruction *MI, BasicBlock *BB)
284 : MemoryAccess(C, Vty, DeleteValue, BB, 1), MemoryInstruction(MI),
285 OptimizedAccessAlias(MayAlias) {
286 setDefiningAccess(DMA);
287 }
288
289 // Use deleteValue() to delete a generic MemoryUseOrDef.
290 ~MemoryUseOrDef() = default;
291
292 void setOptimizedAccessType(Optional<AliasResult> AR) {
293 OptimizedAccessAlias = AR;
294 }
295
296 void setDefiningAccess(MemoryAccess *DMA, bool Optimized = false,
297 Optional<AliasResult> AR = MayAlias) {
298 if (!Optimized) {
299 setOperand(0, DMA);
300 return;
301 }
302 setOptimized(DMA);
303 setOptimizedAccessType(AR);
304 }
305
306private:
307 Instruction *MemoryInstruction;
308 Optional<AliasResult> OptimizedAccessAlias;
309};
310
311template <>
312struct OperandTraits<MemoryUseOrDef>
313 : public FixedNumOperandTraits<MemoryUseOrDef, 1> {};
314DEFINE_TRANSPARENT_OPERAND_ACCESSORS(MemoryUseOrDef, MemoryAccess)MemoryUseOrDef::op_iterator MemoryUseOrDef::op_begin() { return
OperandTraits<MemoryUseOrDef>::op_begin(this); } MemoryUseOrDef
::const_op_iterator MemoryUseOrDef::op_begin() const { return
OperandTraits<MemoryUseOrDef>::op_begin(const_cast<
MemoryUseOrDef*>(this)); } MemoryUseOrDef::op_iterator MemoryUseOrDef
::op_end() { return OperandTraits<MemoryUseOrDef>::op_end
(this); } MemoryUseOrDef::const_op_iterator MemoryUseOrDef::op_end
() const { return OperandTraits<MemoryUseOrDef>::op_end
(const_cast<MemoryUseOrDef*>(this)); } MemoryAccess *MemoryUseOrDef
::getOperand(unsigned i_nocapture) const { (static_cast <bool
> (i_nocapture < OperandTraits<MemoryUseOrDef>::operands
(this) && "getOperand() out of range!") ? void (0) : __assert_fail
("i_nocapture < OperandTraits<MemoryUseOrDef>::operands(this) && \"getOperand() out of range!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 314, __extension__ __PRETTY_FUNCTION__)); return cast_or_null
<MemoryAccess>( OperandTraits<MemoryUseOrDef>::op_begin
(const_cast<MemoryUseOrDef*>(this))[i_nocapture].get())
; } void MemoryUseOrDef::setOperand(unsigned i_nocapture, MemoryAccess
*Val_nocapture) { (static_cast <bool> (i_nocapture <
OperandTraits<MemoryUseOrDef>::operands(this) &&
"setOperand() out of range!") ? void (0) : __assert_fail ("i_nocapture < OperandTraits<MemoryUseOrDef>::operands(this) && \"setOperand() out of range!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 314, __extension__ __PRETTY_FUNCTION__)); OperandTraits<
MemoryUseOrDef>::op_begin(this)[i_nocapture] = Val_nocapture
; } unsigned MemoryUseOrDef::getNumOperands() const { return OperandTraits
<MemoryUseOrDef>::operands(this); } template <int Idx_nocapture
> Use &MemoryUseOrDef::Op() { return this->OpFrom<
Idx_nocapture>(this); } template <int Idx_nocapture>
const Use &MemoryUseOrDef::Op() const { return this->
OpFrom<Idx_nocapture>(this); }
315
316/// \brief Represents read-only accesses to memory
317///
318/// In particular, the set of Instructions that will be represented by
319/// MemoryUse's is exactly the set of Instructions for which
320/// AliasAnalysis::getModRefInfo returns "Ref".
321class MemoryUse final : public MemoryUseOrDef {
322public:
323 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(MemoryAccess)public: inline MemoryAccess *getOperand(unsigned) const; inline
void setOperand(unsigned, MemoryAccess*); inline op_iterator
op_begin(); inline const_op_iterator op_begin() const; inline
op_iterator op_end(); inline const_op_iterator op_end() const
; protected: template <int> inline Use &Op(); template
<int> inline const Use &Op() const; public: inline
unsigned getNumOperands() const
;
324
325 MemoryUse(LLVMContext &C, MemoryAccess *DMA, Instruction *MI, BasicBlock *BB)
326 : MemoryUseOrDef(C, DMA, MemoryUseVal, deleteMe, MI, BB) {}
327
328 // allocate space for exactly one operand
329 void *operator new(size_t s) { return User::operator new(s, 1); }
330
331 static bool classof(const Value *MA) {
332 return MA->getValueID() == MemoryUseVal;
333 }
334
335 void print(raw_ostream &OS) const;
336
337 void setOptimized(MemoryAccess *DMA) {
338 OptimizedID = DMA->getID();
339 setOperand(0, DMA);
340 }
341
342 bool isOptimized() const {
343 return getDefiningAccess() && OptimizedID == getDefiningAccess()->getID();
344 }
345
346 MemoryAccess *getOptimized() const {
347 return getDefiningAccess();
348 }
349
350 void resetOptimized() {
351 OptimizedID = INVALID_MEMORYACCESS_ID;
352 }
353
354protected:
355 friend class MemorySSA;
356
357private:
358 static void deleteMe(DerivedUser *Self);
359
360 unsigned OptimizedID = INVALID_MEMORYACCESS_ID;
361};
362
363template <>
364struct OperandTraits<MemoryUse> : public FixedNumOperandTraits<MemoryUse, 1> {};
365DEFINE_TRANSPARENT_OPERAND_ACCESSORS(MemoryUse, MemoryAccess)MemoryUse::op_iterator MemoryUse::op_begin() { return OperandTraits
<MemoryUse>::op_begin(this); } MemoryUse::const_op_iterator
MemoryUse::op_begin() const { return OperandTraits<MemoryUse
>::op_begin(const_cast<MemoryUse*>(this)); } MemoryUse
::op_iterator MemoryUse::op_end() { return OperandTraits<MemoryUse
>::op_end(this); } MemoryUse::const_op_iterator MemoryUse::
op_end() const { return OperandTraits<MemoryUse>::op_end
(const_cast<MemoryUse*>(this)); } MemoryAccess *MemoryUse
::getOperand(unsigned i_nocapture) const { (static_cast <bool
> (i_nocapture < OperandTraits<MemoryUse>::operands
(this) && "getOperand() out of range!") ? void (0) : __assert_fail
("i_nocapture < OperandTraits<MemoryUse>::operands(this) && \"getOperand() out of range!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 365, __extension__ __PRETTY_FUNCTION__)); return cast_or_null
<MemoryAccess>( OperandTraits<MemoryUse>::op_begin
(const_cast<MemoryUse*>(this))[i_nocapture].get()); } void
MemoryUse::setOperand(unsigned i_nocapture, MemoryAccess *Val_nocapture
) { (static_cast <bool> (i_nocapture < OperandTraits
<MemoryUse>::operands(this) && "setOperand() out of range!"
) ? void (0) : __assert_fail ("i_nocapture < OperandTraits<MemoryUse>::operands(this) && \"setOperand() out of range!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 365, __extension__ __PRETTY_FUNCTION__)); OperandTraits<
MemoryUse>::op_begin(this)[i_nocapture] = Val_nocapture; }
unsigned MemoryUse::getNumOperands() const { return OperandTraits
<MemoryUse>::operands(this); } template <int Idx_nocapture
> Use &MemoryUse::Op() { return this->OpFrom<Idx_nocapture
>(this); } template <int Idx_nocapture> const Use &
MemoryUse::Op() const { return this->OpFrom<Idx_nocapture
>(this); }
366
367/// \brief Represents a read-write access to memory, whether it is a must-alias,
368/// or a may-alias.
369///
370/// In particular, the set of Instructions that will be represented by
371/// MemoryDef's is exactly the set of Instructions for which
372/// AliasAnalysis::getModRefInfo returns "Mod" or "ModRef".
373/// Note that, in order to provide def-def chains, all defs also have a use
374/// associated with them. This use points to the nearest reaching
375/// MemoryDef/MemoryPhi.
376class MemoryDef final : public MemoryUseOrDef {
377public:
378 friend class MemorySSA;
379
380 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(MemoryAccess)public: inline MemoryAccess *getOperand(unsigned) const; inline
void setOperand(unsigned, MemoryAccess*); inline op_iterator
op_begin(); inline const_op_iterator op_begin() const; inline
op_iterator op_end(); inline const_op_iterator op_end() const
; protected: template <int> inline Use &Op(); template
<int> inline const Use &Op() const; public: inline
unsigned getNumOperands() const
;
381
382 MemoryDef(LLVMContext &C, MemoryAccess *DMA, Instruction *MI, BasicBlock *BB,
383 unsigned Ver)
384 : MemoryUseOrDef(C, DMA, MemoryDefVal, deleteMe, MI, BB), ID(Ver) {}
385
386 // allocate space for exactly one operand
387 void *operator new(size_t s) { return User::operator new(s, 1); }
388
389 static bool classof(const Value *MA) {
390 return MA->getValueID() == MemoryDefVal;
391 }
392
393 void setOptimized(MemoryAccess *MA) {
394 Optimized = MA;
395 OptimizedID = getDefiningAccess()->getID();
396 }
397
398 MemoryAccess *getOptimized() const {
399 return cast_or_null<MemoryAccess>(Optimized);
400 }
401
402 bool isOptimized() const {
403 return getOptimized() && getDefiningAccess() &&
404 OptimizedID == getDefiningAccess()->getID();
405 }
406
407 void resetOptimized() {
408 OptimizedID = INVALID_MEMORYACCESS_ID;
409 }
410
411 void print(raw_ostream &OS) const;
412
413 unsigned getID() const { return ID; }
414
415private:
416 static void deleteMe(DerivedUser *Self);
417
418 const unsigned ID;
419 unsigned OptimizedID = INVALID_MEMORYACCESS_ID;
420 WeakVH Optimized;
421};
422
423template <>
424struct OperandTraits<MemoryDef> : public FixedNumOperandTraits<MemoryDef, 1> {};
425DEFINE_TRANSPARENT_OPERAND_ACCESSORS(MemoryDef, MemoryAccess)MemoryDef::op_iterator MemoryDef::op_begin() { return OperandTraits
<MemoryDef>::op_begin(this); } MemoryDef::const_op_iterator
MemoryDef::op_begin() const { return OperandTraits<MemoryDef
>::op_begin(const_cast<MemoryDef*>(this)); } MemoryDef
::op_iterator MemoryDef::op_end() { return OperandTraits<MemoryDef
>::op_end(this); } MemoryDef::const_op_iterator MemoryDef::
op_end() const { return OperandTraits<MemoryDef>::op_end
(const_cast<MemoryDef*>(this)); } MemoryAccess *MemoryDef
::getOperand(unsigned i_nocapture) const { (static_cast <bool
> (i_nocapture < OperandTraits<MemoryDef>::operands
(this) && "getOperand() out of range!") ? void (0) : __assert_fail
("i_nocapture < OperandTraits<MemoryDef>::operands(this) && \"getOperand() out of range!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 425, __extension__ __PRETTY_FUNCTION__)); return cast_or_null
<MemoryAccess>( OperandTraits<MemoryDef>::op_begin
(const_cast<MemoryDef*>(this))[i_nocapture].get()); } void
MemoryDef::setOperand(unsigned i_nocapture, MemoryAccess *Val_nocapture
) { (static_cast <bool> (i_nocapture < OperandTraits
<MemoryDef>::operands(this) && "setOperand() out of range!"
) ? void (0) : __assert_fail ("i_nocapture < OperandTraits<MemoryDef>::operands(this) && \"setOperand() out of range!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 425, __extension__ __PRETTY_FUNCTION__)); OperandTraits<
MemoryDef>::op_begin(this)[i_nocapture] = Val_nocapture; }
unsigned MemoryDef::getNumOperands() const { return OperandTraits
<MemoryDef>::operands(this); } template <int Idx_nocapture
> Use &MemoryDef::Op() { return this->OpFrom<Idx_nocapture
>(this); } template <int Idx_nocapture> const Use &
MemoryDef::Op() const { return this->OpFrom<Idx_nocapture
>(this); }
426
427/// \brief Represents phi nodes for memory accesses.
428///
429/// These have the same semantic as regular phi nodes, with the exception that
430/// only one phi will ever exist in a given basic block.
431/// Guaranteeing one phi per block means guaranteeing there is only ever one
432/// valid reaching MemoryDef/MemoryPHI along each path to the phi node.
433/// This is ensured by not allowing disambiguation of the RHS of a MemoryDef or
434/// a MemoryPhi's operands.
435/// That is, given
436/// if (a) {
437/// store %a
438/// store %b
439/// }
440/// it *must* be transformed into
441/// if (a) {
442/// 1 = MemoryDef(liveOnEntry)
443/// store %a
444/// 2 = MemoryDef(1)
445/// store %b
446/// }
447/// and *not*
448/// if (a) {
449/// 1 = MemoryDef(liveOnEntry)
450/// store %a
451/// 2 = MemoryDef(liveOnEntry)
452/// store %b
453/// }
454/// even if the two stores do not conflict. Otherwise, both 1 and 2 reach the
455/// end of the branch, and if there are not two phi nodes, one will be
456/// disconnected completely from the SSA graph below that point.
457/// Because MemoryUse's do not generate new definitions, they do not have this
458/// issue.
459class MemoryPhi final : public MemoryAccess {
460 // allocate space for exactly zero operands
461 void *operator new(size_t s) { return User::operator new(s); }
462
463public:
464 /// Provide fast operand accessors
465 DECLARE_TRANSPARENT_OPERAND_ACCESSORS(MemoryAccess)public: inline MemoryAccess *getOperand(unsigned) const; inline
void setOperand(unsigned, MemoryAccess*); inline op_iterator
op_begin(); inline const_op_iterator op_begin() const; inline
op_iterator op_end(); inline const_op_iterator op_end() const
; protected: template <int> inline Use &Op(); template
<int> inline const Use &Op() const; public: inline
unsigned getNumOperands() const
;
466
467 MemoryPhi(LLVMContext &C, BasicBlock *BB, unsigned Ver, unsigned NumPreds = 0)
468 : MemoryAccess(C, MemoryPhiVal, deleteMe, BB, 0), ID(Ver),
469 ReservedSpace(NumPreds) {
470 allocHungoffUses(ReservedSpace);
471 }
472
473 // Block iterator interface. This provides access to the list of incoming
474 // basic blocks, which parallels the list of incoming values.
475 using block_iterator = BasicBlock **;
476 using const_block_iterator = BasicBlock *const *;
477
478 block_iterator block_begin() {
479 auto *Ref = reinterpret_cast<Use::UserRef *>(op_begin() + ReservedSpace);
480 return reinterpret_cast<block_iterator>(Ref + 1);
481 }
482
483 const_block_iterator block_begin() const {
484 const auto *Ref =
485 reinterpret_cast<const Use::UserRef *>(op_begin() + ReservedSpace);
486 return reinterpret_cast<const_block_iterator>(Ref + 1);
487 }
488
489 block_iterator block_end() { return block_begin() + getNumOperands(); }
490
491 const_block_iterator block_end() const {
492 return block_begin() + getNumOperands();
493 }
494
495 iterator_range<block_iterator> blocks() {
496 return make_range(block_begin(), block_end());
497 }
498
499 iterator_range<const_block_iterator> blocks() const {
500 return make_range(block_begin(), block_end());
501 }
502
503 op_range incoming_values() { return operands(); }
504
505 const_op_range incoming_values() const { return operands(); }
506
507 /// \brief Return the number of incoming edges
508 unsigned getNumIncomingValues() const { return getNumOperands(); }
509
510 /// \brief Return incoming value number x
511 MemoryAccess *getIncomingValue(unsigned I) const { return getOperand(I); }
512 void setIncomingValue(unsigned I, MemoryAccess *V) {
513 assert(V && "PHI node got a null value!")(static_cast <bool> (V && "PHI node got a null value!"
) ? void (0) : __assert_fail ("V && \"PHI node got a null value!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 513, __extension__ __PRETTY_FUNCTION__))
;
514 setOperand(I, V);
515 }
516
517 static unsigned getOperandNumForIncomingValue(unsigned I) { return I; }
518 static unsigned getIncomingValueNumForOperand(unsigned I) { return I; }
519
520 /// \brief Return incoming basic block number @p i.
521 BasicBlock *getIncomingBlock(unsigned I) const { return block_begin()[I]; }
522
523 /// \brief Return incoming basic block corresponding
524 /// to an operand of the PHI.
525 BasicBlock *getIncomingBlock(const Use &U) const {
526 assert(this == U.getUser() && "Iterator doesn't point to PHI's Uses?")(static_cast <bool> (this == U.getUser() && "Iterator doesn't point to PHI's Uses?"
) ? void (0) : __assert_fail ("this == U.getUser() && \"Iterator doesn't point to PHI's Uses?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 526, __extension__ __PRETTY_FUNCTION__))
;
527 return getIncomingBlock(unsigned(&U - op_begin()));
528 }
529
530 /// \brief Return incoming basic block corresponding
531 /// to value use iterator.
532 BasicBlock *getIncomingBlock(MemoryAccess::const_user_iterator I) const {
533 return getIncomingBlock(I.getUse());
534 }
535
536 void setIncomingBlock(unsigned I, BasicBlock *BB) {
537 assert(BB && "PHI node got a null basic block!")(static_cast <bool> (BB && "PHI node got a null basic block!"
) ? void (0) : __assert_fail ("BB && \"PHI node got a null basic block!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 537, __extension__ __PRETTY_FUNCTION__))
;
538 block_begin()[I] = BB;
539 }
540
541 /// \brief Add an incoming value to the end of the PHI list
542 void addIncoming(MemoryAccess *V, BasicBlock *BB) {
543 if (getNumOperands() == ReservedSpace)
544 growOperands(); // Get more space!
545 // Initialize some new operands.
546 setNumHungOffUseOperands(getNumOperands() + 1);
547 setIncomingValue(getNumOperands() - 1, V);
548 setIncomingBlock(getNumOperands() - 1, BB);
549 }
550
551 /// \brief Return the first index of the specified basic
552 /// block in the value list for this PHI. Returns -1 if no instance.
553 int getBasicBlockIndex(const BasicBlock *BB) const {
554 for (unsigned I = 0, E = getNumOperands(); I != E; ++I)
555 if (block_begin()[I] == BB)
556 return I;
557 return -1;
558 }
559
560 Value *getIncomingValueForBlock(const BasicBlock *BB) const {
561 int Idx = getBasicBlockIndex(BB);
562 assert(Idx >= 0 && "Invalid basic block argument!")(static_cast <bool> (Idx >= 0 && "Invalid basic block argument!"
) ? void (0) : __assert_fail ("Idx >= 0 && \"Invalid basic block argument!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 562, __extension__ __PRETTY_FUNCTION__))
;
563 return getIncomingValue(Idx);
564 }
565
566 static bool classof(const Value *V) {
567 return V->getValueID() == MemoryPhiVal;
568 }
569
570 void print(raw_ostream &OS) const;
571
572 unsigned getID() const { return ID; }
573
574protected:
575 friend class MemorySSA;
576
577 /// \brief this is more complicated than the generic
578 /// User::allocHungoffUses, because we have to allocate Uses for the incoming
579 /// values and pointers to the incoming blocks, all in one allocation.
580 void allocHungoffUses(unsigned N) {
581 User::allocHungoffUses(N, /* IsPhi */ true);
582 }
583
584private:
585 // For debugging only
586 const unsigned ID;
587 unsigned ReservedSpace;
588
589 /// \brief This grows the operand list in response to a push_back style of
590 /// operation. This grows the number of ops by 1.5 times.
591 void growOperands() {
592 unsigned E = getNumOperands();
593 // 2 op PHI nodes are VERY common, so reserve at least enough for that.
594 ReservedSpace = std::max(E + E / 2, 2u);
595 growHungoffUses(ReservedSpace, /* IsPhi */ true);
596 }
597
598 static void deleteMe(DerivedUser *Self);
599};
600
601inline unsigned MemoryAccess::getID() const {
602 assert((isa<MemoryDef>(this) || isa<MemoryPhi>(this)) &&(static_cast <bool> ((isa<MemoryDef>(this) || isa
<MemoryPhi>(this)) && "only memory defs and phis have ids"
) ? void (0) : __assert_fail ("(isa<MemoryDef>(this) || isa<MemoryPhi>(this)) && \"only memory defs and phis have ids\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 603, __extension__ __PRETTY_FUNCTION__))
603 "only memory defs and phis have ids")(static_cast <bool> ((isa<MemoryDef>(this) || isa
<MemoryPhi>(this)) && "only memory defs and phis have ids"
) ? void (0) : __assert_fail ("(isa<MemoryDef>(this) || isa<MemoryPhi>(this)) && \"only memory defs and phis have ids\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 603, __extension__ __PRETTY_FUNCTION__))
;
604 if (const auto *MD = dyn_cast<MemoryDef>(this))
605 return MD->getID();
606 return cast<MemoryPhi>(this)->getID();
607}
608
609inline bool MemoryUseOrDef::isOptimized() const {
610 if (const auto *MD = dyn_cast<MemoryDef>(this))
611 return MD->isOptimized();
612 return cast<MemoryUse>(this)->isOptimized();
613}
614
615inline MemoryAccess *MemoryUseOrDef::getOptimized() const {
616 if (const auto *MD = dyn_cast<MemoryDef>(this))
617 return MD->getOptimized();
618 return cast<MemoryUse>(this)->getOptimized();
619}
620
621inline void MemoryUseOrDef::setOptimized(MemoryAccess *MA) {
622 if (auto *MD = dyn_cast<MemoryDef>(this))
623 MD->setOptimized(MA);
624 else
625 cast<MemoryUse>(this)->setOptimized(MA);
626}
627
628inline void MemoryUseOrDef::resetOptimized() {
629 if (auto *MD = dyn_cast<MemoryDef>(this))
630 MD->resetOptimized();
631 else
632 cast<MemoryUse>(this)->resetOptimized();
633}
634
635template <> struct OperandTraits<MemoryPhi> : public HungoffOperandTraits<2> {};
636DEFINE_TRANSPARENT_OPERAND_ACCESSORS(MemoryPhi, MemoryAccess)MemoryPhi::op_iterator MemoryPhi::op_begin() { return OperandTraits
<MemoryPhi>::op_begin(this); } MemoryPhi::const_op_iterator
MemoryPhi::op_begin() const { return OperandTraits<MemoryPhi
>::op_begin(const_cast<MemoryPhi*>(this)); } MemoryPhi
::op_iterator MemoryPhi::op_end() { return OperandTraits<MemoryPhi
>::op_end(this); } MemoryPhi::const_op_iterator MemoryPhi::
op_end() const { return OperandTraits<MemoryPhi>::op_end
(const_cast<MemoryPhi*>(this)); } MemoryAccess *MemoryPhi
::getOperand(unsigned i_nocapture) const { (static_cast <bool
> (i_nocapture < OperandTraits<MemoryPhi>::operands
(this) && "getOperand() out of range!") ? void (0) : __assert_fail
("i_nocapture < OperandTraits<MemoryPhi>::operands(this) && \"getOperand() out of range!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 636, __extension__ __PRETTY_FUNCTION__)); return cast_or_null
<MemoryAccess>( OperandTraits<MemoryPhi>::op_begin
(const_cast<MemoryPhi*>(this))[i_nocapture].get()); } void
MemoryPhi::setOperand(unsigned i_nocapture, MemoryAccess *Val_nocapture
) { (static_cast <bool> (i_nocapture < OperandTraits
<MemoryPhi>::operands(this) && "setOperand() out of range!"
) ? void (0) : __assert_fail ("i_nocapture < OperandTraits<MemoryPhi>::operands(this) && \"setOperand() out of range!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 636, __extension__ __PRETTY_FUNCTION__)); OperandTraits<
MemoryPhi>::op_begin(this)[i_nocapture] = Val_nocapture; }
unsigned MemoryPhi::getNumOperands() const { return OperandTraits
<MemoryPhi>::operands(this); } template <int Idx_nocapture
> Use &MemoryPhi::Op() { return this->OpFrom<Idx_nocapture
>(this); } template <int Idx_nocapture> const Use &
MemoryPhi::Op() const { return this->OpFrom<Idx_nocapture
>(this); }
637
638/// \brief Encapsulates MemorySSA, including all data associated with memory
639/// accesses.
640class MemorySSA {
641public:
642 MemorySSA(Function &, AliasAnalysis *, DominatorTree *);
643 ~MemorySSA();
644
645 MemorySSAWalker *getWalker();
646
647 /// \brief Given a memory Mod/Ref'ing instruction, get the MemorySSA
648 /// access associated with it. If passed a basic block gets the memory phi
649 /// node that exists for that block, if there is one. Otherwise, this will get
650 /// a MemoryUseOrDef.
651 MemoryUseOrDef *getMemoryAccess(const Instruction *) const;
652 MemoryPhi *getMemoryAccess(const BasicBlock *BB) const;
653
654 void dump() const;
655 void print(raw_ostream &) const;
656
657 /// \brief Return true if \p MA represents the live on entry value
658 ///
659 /// Loads and stores from pointer arguments and other global values may be
660 /// defined by memory operations that do not occur in the current function, so
661 /// they may be live on entry to the function. MemorySSA represents such
662 /// memory state by the live on entry definition, which is guaranteed to occur
663 /// before any other memory access in the function.
664 inline bool isLiveOnEntryDef(const MemoryAccess *MA) const {
665 return MA == LiveOnEntryDef.get();
666 }
667
668 inline MemoryAccess *getLiveOnEntryDef() const {
669 return LiveOnEntryDef.get();
670 }
671
672 // Sadly, iplists, by default, owns and deletes pointers added to the
673 // list. It's not currently possible to have two iplists for the same type,
674 // where one owns the pointers, and one does not. This is because the traits
675 // are per-type, not per-tag. If this ever changes, we should make the
676 // DefList an iplist.
677 using AccessList = iplist<MemoryAccess, ilist_tag<MSSAHelpers::AllAccessTag>>;
678 using DefsList =
679 simple_ilist<MemoryAccess, ilist_tag<MSSAHelpers::DefsOnlyTag>>;
680
681 /// \brief Return the list of MemoryAccess's for a given basic block.
682 ///
683 /// This list is not modifiable by the user.
684 const AccessList *getBlockAccesses(const BasicBlock *BB) const {
685 return getWritableBlockAccesses(BB);
4
Calling 'MemorySSA::getWritableBlockAccesses'
7
Returning from 'MemorySSA::getWritableBlockAccesses'
686 }
687
688 /// \brief Return the list of MemoryDef's and MemoryPhi's for a given basic
689 /// block.
690 ///
691 /// This list is not modifiable by the user.
692 const DefsList *getBlockDefs(const BasicBlock *BB) const {
693 return getWritableBlockDefs(BB);
694 }
695
696 /// \brief Given two memory accesses in the same basic block, determine
697 /// whether MemoryAccess \p A dominates MemoryAccess \p B.
698 bool locallyDominates(const MemoryAccess *A, const MemoryAccess *B) const;
699
700 /// \brief Given two memory accesses in potentially different blocks,
701 /// determine whether MemoryAccess \p A dominates MemoryAccess \p B.
702 bool dominates(const MemoryAccess *A, const MemoryAccess *B) const;
703
704 /// \brief Given a MemoryAccess and a Use, determine whether MemoryAccess \p A
705 /// dominates Use \p B.
706 bool dominates(const MemoryAccess *A, const Use &B) const;
707
708 /// \brief Verify that MemorySSA is self consistent (IE definitions dominate
709 /// all uses, uses appear in the right places). This is used by unit tests.
710 void verifyMemorySSA() const;
711
712 /// Used in various insertion functions to specify whether we are talking
713 /// about the beginning or end of a block.
714 enum InsertionPlace { Beginning, End };
715
716protected:
717 // Used by Memory SSA annotater, dumpers, and wrapper pass
718 friend class MemorySSAAnnotatedWriter;
719 friend class MemorySSAPrinterLegacyPass;
720 friend class MemorySSAUpdater;
721
722 void verifyDefUses(Function &F) const;
723 void verifyDomination(Function &F) const;
724 void verifyOrdering(Function &F) const;
725
726 // This is used by the use optimizer and updater.
727 AccessList *getWritableBlockAccesses(const BasicBlock *BB) const {
728 auto It = PerBlockAccesses.find(BB);
729 return It == PerBlockAccesses.end() ? nullptr : It->second.get();
5
Assuming the condition is false
6
'?' condition is false
730 }
731
732 // This is used by the use optimizer and updater.
733 DefsList *getWritableBlockDefs(const BasicBlock *BB) const {
734 auto It = PerBlockDefs.find(BB);
735 return It == PerBlockDefs.end() ? nullptr : It->second.get();
736 }
737
738 // These is used by the updater to perform various internal MemorySSA
739 // machinsations. They do not always leave the IR in a correct state, and
740 // relies on the updater to fixup what it breaks, so it is not public.
741
742 void moveTo(MemoryUseOrDef *What, BasicBlock *BB, AccessList::iterator Where);
743 void moveTo(MemoryUseOrDef *What, BasicBlock *BB, InsertionPlace Point);
744
745 // Rename the dominator tree branch rooted at BB.
746 void renamePass(BasicBlock *BB, MemoryAccess *IncomingVal,
747 SmallPtrSetImpl<BasicBlock *> &Visited) {
748 renamePass(DT->getNode(BB), IncomingVal, Visited, true, true);
749 }
750
751 void removeFromLookups(MemoryAccess *);
752 void removeFromLists(MemoryAccess *, bool ShouldDelete = true);
753 void insertIntoListsForBlock(MemoryAccess *, const BasicBlock *,
754 InsertionPlace);
755 void insertIntoListsBefore(MemoryAccess *, const BasicBlock *,
756 AccessList::iterator);
757 MemoryUseOrDef *createDefinedAccess(Instruction *, MemoryAccess *);
758
759private:
760 class CachingWalker;
761 class OptimizeUses;
762
763 CachingWalker *getWalkerImpl();
764 void buildMemorySSA();
765 void optimizeUses();
766
767 void verifyUseInDefs(MemoryAccess *, MemoryAccess *) const;
768
769 using AccessMap = DenseMap<const BasicBlock *, std::unique_ptr<AccessList>>;
770 using DefsMap = DenseMap<const BasicBlock *, std::unique_ptr<DefsList>>;
771
772 void
773 determineInsertionPoint(const SmallPtrSetImpl<BasicBlock *> &DefiningBlocks);
774 void markUnreachableAsLiveOnEntry(BasicBlock *BB);
775 bool dominatesUse(const MemoryAccess *, const MemoryAccess *) const;
776 MemoryPhi *createMemoryPhi(BasicBlock *BB);
777 MemoryUseOrDef *createNewAccess(Instruction *);
778 MemoryAccess *findDominatingDef(BasicBlock *, enum InsertionPlace);
779 void placePHINodes(const SmallPtrSetImpl<BasicBlock *> &,
780 const DenseMap<const BasicBlock *, unsigned int> &);
781 MemoryAccess *renameBlock(BasicBlock *, MemoryAccess *, bool);
782 void renameSuccessorPhis(BasicBlock *, MemoryAccess *, bool);
783 void renamePass(DomTreeNode *, MemoryAccess *IncomingVal,
784 SmallPtrSetImpl<BasicBlock *> &Visited,
785 bool SkipVisited = false, bool RenameAllUses = false);
786 AccessList *getOrCreateAccessList(const BasicBlock *);
787 DefsList *getOrCreateDefsList(const BasicBlock *);
788 void renumberBlock(const BasicBlock *) const;
789 AliasAnalysis *AA;
790 DominatorTree *DT;
791 Function &F;
792
793 // Memory SSA mappings
794 DenseMap<const Value *, MemoryAccess *> ValueToMemoryAccess;
795
796 // These two mappings contain the main block to access/def mappings for
797 // MemorySSA. The list contained in PerBlockAccesses really owns all the
798 // MemoryAccesses.
799 // Both maps maintain the invariant that if a block is found in them, the
800 // corresponding list is not empty, and if a block is not found in them, the
801 // corresponding list is empty.
802 AccessMap PerBlockAccesses;
803 DefsMap PerBlockDefs;
804 std::unique_ptr<MemoryAccess, ValueDeleter> LiveOnEntryDef;
805
806 // Domination mappings
807 // Note that the numbering is local to a block, even though the map is
808 // global.
809 mutable SmallPtrSet<const BasicBlock *, 16> BlockNumberingValid;
810 mutable DenseMap<const MemoryAccess *, unsigned long> BlockNumbering;
811
812 // Memory SSA building info
813 std::unique_ptr<CachingWalker> Walker;
814 unsigned NextID;
815};
816
817// Internal MemorySSA utils, for use by MemorySSA classes and walkers
818class MemorySSAUtil {
819protected:
820 friend class GVNHoist;
821 friend class MemorySSAWalker;
822
823 // This function should not be used by new passes.
824 static bool defClobbersUseOrDef(MemoryDef *MD, const MemoryUseOrDef *MU,
825 AliasAnalysis &AA);
826};
827
828// This pass does eager building and then printing of MemorySSA. It is used by
829// the tests to be able to build, dump, and verify Memory SSA.
830class MemorySSAPrinterLegacyPass : public FunctionPass {
831public:
832 MemorySSAPrinterLegacyPass();
833
834 bool runOnFunction(Function &) override;
835 void getAnalysisUsage(AnalysisUsage &AU) const override;
836
837 static char ID;
838};
839
840/// An analysis that produces \c MemorySSA for a function.
841///
842class MemorySSAAnalysis : public AnalysisInfoMixin<MemorySSAAnalysis> {
843 friend AnalysisInfoMixin<MemorySSAAnalysis>;
844
845 static AnalysisKey Key;
846
847public:
848 // Wrap MemorySSA result to ensure address stability of internal MemorySSA
849 // pointers after construction. Use a wrapper class instead of plain
850 // unique_ptr<MemorySSA> to avoid build breakage on MSVC.
851 struct Result {
852 Result(std::unique_ptr<MemorySSA> &&MSSA) : MSSA(std::move(MSSA)) {}
853
854 MemorySSA &getMSSA() { return *MSSA.get(); }
855
856 std::unique_ptr<MemorySSA> MSSA;
857 };
858
859 Result run(Function &F, FunctionAnalysisManager &AM);
860};
861
862/// \brief Printer pass for \c MemorySSA.
863class MemorySSAPrinterPass : public PassInfoMixin<MemorySSAPrinterPass> {
864 raw_ostream &OS;
865
866public:
867 explicit MemorySSAPrinterPass(raw_ostream &OS) : OS(OS) {}
868
869 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
870};
871
872/// \brief Verifier pass for \c MemorySSA.
873struct MemorySSAVerifierPass : PassInfoMixin<MemorySSAVerifierPass> {
874 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
875};
876
877/// \brief Legacy analysis pass which computes \c MemorySSA.
878class MemorySSAWrapperPass : public FunctionPass {
879public:
880 MemorySSAWrapperPass();
881
882 static char ID;
883
884 bool runOnFunction(Function &) override;
885 void releaseMemory() override;
886 MemorySSA &getMSSA() { return *MSSA; }
887 const MemorySSA &getMSSA() const { return *MSSA; }
888
889 void getAnalysisUsage(AnalysisUsage &AU) const override;
890
891 void verifyAnalysis() const override;
892 void print(raw_ostream &OS, const Module *M = nullptr) const override;
893
894private:
895 std::unique_ptr<MemorySSA> MSSA;
896};
897
898/// \brief This is the generic walker interface for walkers of MemorySSA.
899/// Walkers are used to be able to further disambiguate the def-use chains
900/// MemorySSA gives you, or otherwise produce better info than MemorySSA gives
901/// you.
902/// In particular, while the def-use chains provide basic information, and are
903/// guaranteed to give, for example, the nearest may-aliasing MemoryDef for a
904/// MemoryUse as AliasAnalysis considers it, a user mant want better or other
905/// information. In particular, they may want to use SCEV info to further
906/// disambiguate memory accesses, or they may want the nearest dominating
907/// may-aliasing MemoryDef for a call or a store. This API enables a
908/// standardized interface to getting and using that info.
909class MemorySSAWalker {
910public:
911 MemorySSAWalker(MemorySSA *);
912 virtual ~MemorySSAWalker() = default;
913
914 using MemoryAccessSet = SmallVector<MemoryAccess *, 8>;
915
916 /// \brief Given a memory Mod/Ref/ModRef'ing instruction, calling this
917 /// will give you the nearest dominating MemoryAccess that Mod's the location
918 /// the instruction accesses (by skipping any def which AA can prove does not
919 /// alias the location(s) accessed by the instruction given).
920 ///
921 /// Note that this will return a single access, and it must dominate the
922 /// Instruction, so if an operand of a MemoryPhi node Mod's the instruction,
923 /// this will return the MemoryPhi, not the operand. This means that
924 /// given:
925 /// if (a) {
926 /// 1 = MemoryDef(liveOnEntry)
927 /// store %a
928 /// } else {
929 /// 2 = MemoryDef(liveOnEntry)
930 /// store %b
931 /// }
932 /// 3 = MemoryPhi(2, 1)
933 /// MemoryUse(3)
934 /// load %a
935 ///
936 /// calling this API on load(%a) will return the MemoryPhi, not the MemoryDef
937 /// in the if (a) branch.
938 MemoryAccess *getClobberingMemoryAccess(const Instruction *I) {
939 MemoryAccess *MA = MSSA->getMemoryAccess(I);
940 assert(MA && "Handed an instruction that MemorySSA doesn't recognize?")(static_cast <bool> (MA && "Handed an instruction that MemorySSA doesn't recognize?"
) ? void (0) : __assert_fail ("MA && \"Handed an instruction that MemorySSA doesn't recognize?\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 940, __extension__ __PRETTY_FUNCTION__))
;
941 return getClobberingMemoryAccess(MA);
942 }
943
944 /// Does the same thing as getClobberingMemoryAccess(const Instruction *I),
945 /// but takes a MemoryAccess instead of an Instruction.
946 virtual MemoryAccess *getClobberingMemoryAccess(MemoryAccess *) = 0;
947
948 /// \brief Given a potentially clobbering memory access and a new location,
949 /// calling this will give you the nearest dominating clobbering MemoryAccess
950 /// (by skipping non-aliasing def links).
951 ///
952 /// This version of the function is mainly used to disambiguate phi translated
953 /// pointers, where the value of a pointer may have changed from the initial
954 /// memory access. Note that this expects to be handed either a MemoryUse,
955 /// or an already potentially clobbering access. Unlike the above API, if
956 /// given a MemoryDef that clobbers the pointer as the starting access, it
957 /// will return that MemoryDef, whereas the above would return the clobber
958 /// starting from the use side of the memory def.
959 virtual MemoryAccess *getClobberingMemoryAccess(MemoryAccess *,
960 const MemoryLocation &) = 0;
961
962 /// \brief Given a memory access, invalidate anything this walker knows about
963 /// that access.
964 /// This API is used by walkers that store information to perform basic cache
965 /// invalidation. This will be called by MemorySSA at appropriate times for
966 /// the walker it uses or returns.
967 virtual void invalidateInfo(MemoryAccess *) {}
968
969 virtual void verify(const MemorySSA *MSSA) { assert(MSSA == this->MSSA)(static_cast <bool> (MSSA == this->MSSA) ? void (0) :
__assert_fail ("MSSA == this->MSSA", "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 969, __extension__ __PRETTY_FUNCTION__))
; }
970
971protected:
972 friend class MemorySSA; // For updating MSSA pointer in MemorySSA move
973 // constructor.
974 MemorySSA *MSSA;
975};
976
977/// \brief A MemorySSAWalker that does no alias queries, or anything else. It
978/// simply returns the links as they were constructed by the builder.
979class DoNothingMemorySSAWalker final : public MemorySSAWalker {
980public:
981 // Keep the overrides below from hiding the Instruction overload of
982 // getClobberingMemoryAccess.
983 using MemorySSAWalker::getClobberingMemoryAccess;
984
985 MemoryAccess *getClobberingMemoryAccess(MemoryAccess *) override;
986 MemoryAccess *getClobberingMemoryAccess(MemoryAccess *,
987 const MemoryLocation &) override;
988};
989
990using MemoryAccessPair = std::pair<MemoryAccess *, MemoryLocation>;
991using ConstMemoryAccessPair = std::pair<const MemoryAccess *, MemoryLocation>;
992
993/// \brief Iterator base class used to implement const and non-const iterators
994/// over the defining accesses of a MemoryAccess.
995template <class T>
996class memoryaccess_def_iterator_base
997 : public iterator_facade_base<memoryaccess_def_iterator_base<T>,
998 std::forward_iterator_tag, T, ptrdiff_t, T *,
999 T *> {
1000 using BaseT = typename memoryaccess_def_iterator_base::iterator_facade_base;
1001
1002public:
1003 memoryaccess_def_iterator_base(T *Start) : Access(Start) {}
1004 memoryaccess_def_iterator_base() = default;
1005
1006 bool operator==(const memoryaccess_def_iterator_base &Other) const {
1007 return Access == Other.Access && (!Access || ArgNo == Other.ArgNo);
1008 }
1009
1010 // This is a bit ugly, but for MemoryPHI's, unlike PHINodes, you can't get the
1011 // block from the operand in constant time (In a PHINode, the uselist has
1012 // both, so it's just subtraction). We provide it as part of the
1013 // iterator to avoid callers having to linear walk to get the block.
1014 // If the operation becomes constant time on MemoryPHI's, this bit of
1015 // abstraction breaking should be removed.
1016 BasicBlock *getPhiArgBlock() const {
1017 MemoryPhi *MP = dyn_cast<MemoryPhi>(Access);
1018 assert(MP && "Tried to get phi arg block when not iterating over a PHI")(static_cast <bool> (MP && "Tried to get phi arg block when not iterating over a PHI"
) ? void (0) : __assert_fail ("MP && \"Tried to get phi arg block when not iterating over a PHI\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 1018, __extension__ __PRETTY_FUNCTION__))
;
1019 return MP->getIncomingBlock(ArgNo);
1020 }
1021
1022 typename BaseT::iterator::pointer operator*() const {
1023 assert(Access && "Tried to access past the end of our iterator")(static_cast <bool> (Access && "Tried to access past the end of our iterator"
) ? void (0) : __assert_fail ("Access && \"Tried to access past the end of our iterator\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 1023, __extension__ __PRETTY_FUNCTION__))
;
1024 // Go to the first argument for phis, and the defining access for everything
1025 // else.
1026 if (MemoryPhi *MP = dyn_cast<MemoryPhi>(Access))
1027 return MP->getIncomingValue(ArgNo);
1028 return cast<MemoryUseOrDef>(Access)->getDefiningAccess();
1029 }
1030
1031 using BaseT::operator++;
1032 memoryaccess_def_iterator &operator++() {
1033 assert(Access && "Hit end of iterator")(static_cast <bool> (Access && "Hit end of iterator"
) ? void (0) : __assert_fail ("Access && \"Hit end of iterator\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 1033, __extension__ __PRETTY_FUNCTION__))
;
1034 if (MemoryPhi *MP = dyn_cast<MemoryPhi>(Access)) {
1035 if (++ArgNo >= MP->getNumIncomingValues()) {
1036 ArgNo = 0;
1037 Access = nullptr;
1038 }
1039 } else {
1040 Access = nullptr;
1041 }
1042 return *this;
1043 }
1044
1045private:
1046 T *Access = nullptr;
1047 unsigned ArgNo = 0;
1048};
1049
1050inline memoryaccess_def_iterator MemoryAccess::defs_begin() {
1051 return memoryaccess_def_iterator(this);
1052}
1053
1054inline const_memoryaccess_def_iterator MemoryAccess::defs_begin() const {
1055 return const_memoryaccess_def_iterator(this);
1056}
1057
1058inline memoryaccess_def_iterator MemoryAccess::defs_end() {
1059 return memoryaccess_def_iterator();
1060}
1061
1062inline const_memoryaccess_def_iterator MemoryAccess::defs_end() const {
1063 return const_memoryaccess_def_iterator();
1064}
1065
1066/// \brief GraphTraits for a MemoryAccess, which walks defs in the normal case,
1067/// and uses in the inverse case.
1068template <> struct GraphTraits<MemoryAccess *> {
1069 using NodeRef = MemoryAccess *;
1070 using ChildIteratorType = memoryaccess_def_iterator;
1071
1072 static NodeRef getEntryNode(NodeRef N) { return N; }
1073 static ChildIteratorType child_begin(NodeRef N) { return N->defs_begin(); }
1074 static ChildIteratorType child_end(NodeRef N) { return N->defs_end(); }
1075};
1076
1077template <> struct GraphTraits<Inverse<MemoryAccess *>> {
1078 using NodeRef = MemoryAccess *;
1079 using ChildIteratorType = MemoryAccess::iterator;
1080
1081 static NodeRef getEntryNode(NodeRef N) { return N; }
1082 static ChildIteratorType child_begin(NodeRef N) { return N->user_begin(); }
1083 static ChildIteratorType child_end(NodeRef N) { return N->user_end(); }
1084};
1085
1086/// \brief Provide an iterator that walks defs, giving both the memory access,
1087/// and the current pointer location, updating the pointer location as it
1088/// changes due to phi node translation.
1089///
1090/// This iterator, while somewhat specialized, is what most clients actually
1091/// want when walking upwards through MemorySSA def chains. It takes a pair of
1092/// <MemoryAccess,MemoryLocation>, and walks defs, properly translating the
1093/// memory location through phi nodes for the user.
1094class upward_defs_iterator
1095 : public iterator_facade_base<upward_defs_iterator,
1096 std::forward_iterator_tag,
1097 const MemoryAccessPair> {
1098 using BaseT = upward_defs_iterator::iterator_facade_base;
1099
1100public:
1101 upward_defs_iterator(const MemoryAccessPair &Info)
1102 : DefIterator(Info.first), Location(Info.second),
1103 OriginalAccess(Info.first) {
1104 CurrentPair.first = nullptr;
1105
1106 WalkingPhi = Info.first && isa<MemoryPhi>(Info.first);
1107 fillInCurrentPair();
1108 }
1109
1110 upward_defs_iterator() { CurrentPair.first = nullptr; }
1111
1112 bool operator==(const upward_defs_iterator &Other) const {
1113 return DefIterator == Other.DefIterator;
1114 }
1115
1116 BaseT::iterator::reference operator*() const {
1117 assert(DefIterator != OriginalAccess->defs_end() &&(static_cast <bool> (DefIterator != OriginalAccess->
defs_end() && "Tried to access past the end of our iterator"
) ? void (0) : __assert_fail ("DefIterator != OriginalAccess->defs_end() && \"Tried to access past the end of our iterator\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 1118, __extension__ __PRETTY_FUNCTION__))
1118 "Tried to access past the end of our iterator")(static_cast <bool> (DefIterator != OriginalAccess->
defs_end() && "Tried to access past the end of our iterator"
) ? void (0) : __assert_fail ("DefIterator != OriginalAccess->defs_end() && \"Tried to access past the end of our iterator\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 1118, __extension__ __PRETTY_FUNCTION__))
;
1119 return CurrentPair;
1120 }
1121
1122 using BaseT::operator++;
1123 upward_defs_iterator &operator++() {
1124 assert(DefIterator != OriginalAccess->defs_end() &&(static_cast <bool> (DefIterator != OriginalAccess->
defs_end() && "Tried to access past the end of the iterator"
) ? void (0) : __assert_fail ("DefIterator != OriginalAccess->defs_end() && \"Tried to access past the end of the iterator\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 1125, __extension__ __PRETTY_FUNCTION__))
1125 "Tried to access past the end of the iterator")(static_cast <bool> (DefIterator != OriginalAccess->
defs_end() && "Tried to access past the end of the iterator"
) ? void (0) : __assert_fail ("DefIterator != OriginalAccess->defs_end() && \"Tried to access past the end of the iterator\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 1125, __extension__ __PRETTY_FUNCTION__))
;
1126 ++DefIterator;
1127 if (DefIterator != OriginalAccess->defs_end())
1128 fillInCurrentPair();
1129 return *this;
1130 }
1131
1132 BasicBlock *getPhiArgBlock() const { return DefIterator.getPhiArgBlock(); }
1133
1134private:
1135 void fillInCurrentPair() {
1136 CurrentPair.first = *DefIterator;
1137 if (WalkingPhi && Location.Ptr) {
1138 PHITransAddr Translator(
1139 const_cast<Value *>(Location.Ptr),
1140 OriginalAccess->getBlock()->getModule()->getDataLayout(), nullptr);
1141 if (!Translator.PHITranslateValue(OriginalAccess->getBlock(),
1142 DefIterator.getPhiArgBlock(), nullptr,
1143 false))
1144 if (Translator.getAddr() != Location.Ptr) {
1145 CurrentPair.second = Location.getWithNewPtr(Translator.getAddr());
1146 return;
1147 }
1148 }
1149 CurrentPair.second = Location;
1150 }
1151
1152 MemoryAccessPair CurrentPair;
1153 memoryaccess_def_iterator DefIterator;
1154 MemoryLocation Location;
1155 MemoryAccess *OriginalAccess = nullptr;
1156 bool WalkingPhi = false;
1157};
1158
1159inline upward_defs_iterator upward_defs_begin(const MemoryAccessPair &Pair) {
1160 return upward_defs_iterator(Pair);
1161}
1162
1163inline upward_defs_iterator upward_defs_end() { return upward_defs_iterator(); }
1164
1165inline iterator_range<upward_defs_iterator>
1166upward_defs(const MemoryAccessPair &Pair) {
1167 return make_range(upward_defs_begin(Pair), upward_defs_end());
1168}
1169
1170/// Walks the defining accesses of MemoryDefs. Stops after we hit something that
1171/// has no defining use (e.g. a MemoryPhi or liveOnEntry). Note that, when
1172/// comparing against a null def_chain_iterator, this will compare equal only
1173/// after walking said Phi/liveOnEntry.
1174///
1175/// The UseOptimizedChain flag specifies whether to walk the clobbering
1176/// access chain, or all the accesses.
1177///
1178/// Normally, MemoryDef are all just def/use linked together, so a def_chain on
1179/// a MemoryDef will walk all MemoryDefs above it in the program until it hits
1180/// a phi node. The optimized chain walks the clobbering access of a store.
1181/// So if you are just trying to find, given a store, what the next
1182/// thing that would clobber the same memory is, you want the optimized chain.
1183template <class T, bool UseOptimizedChain = false>
1184struct def_chain_iterator
1185 : public iterator_facade_base<def_chain_iterator<T, UseOptimizedChain>,
1186 std::forward_iterator_tag, MemoryAccess *> {
1187 def_chain_iterator() : MA(nullptr) {}
1188 def_chain_iterator(T MA) : MA(MA) {}
1189
1190 T operator*() const { return MA; }
1191
1192 def_chain_iterator &operator++() {
1193 // N.B. liveOnEntry has a null defining access.
1194 if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA)) {
1195 if (UseOptimizedChain && MUD->isOptimized())
1196 MA = MUD->getOptimized();
1197 else
1198 MA = MUD->getDefiningAccess();
1199 } else {
1200 MA = nullptr;
1201 }
1202
1203 return *this;
1204 }
1205
1206 bool operator==(const def_chain_iterator &O) const { return MA == O.MA; }
1207
1208private:
1209 T MA;
1210};
1211
1212template <class T>
1213inline iterator_range<def_chain_iterator<T>>
1214def_chain(T MA, MemoryAccess *UpTo = nullptr) {
1215#ifdef EXPENSIVE_CHECKS
1216 assert((!UpTo || find(def_chain(MA), UpTo) != def_chain_iterator<T>()) &&(static_cast <bool> ((!UpTo || find(def_chain(MA), UpTo
) != def_chain_iterator<T>()) && "UpTo isn't in the def chain!"
) ? void (0) : __assert_fail ("(!UpTo || find(def_chain(MA), UpTo) != def_chain_iterator<T>()) && \"UpTo isn't in the def chain!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 1217, __extension__ __PRETTY_FUNCTION__))
1217 "UpTo isn't in the def chain!")(static_cast <bool> ((!UpTo || find(def_chain(MA), UpTo
) != def_chain_iterator<T>()) && "UpTo isn't in the def chain!"
) ? void (0) : __assert_fail ("(!UpTo || find(def_chain(MA), UpTo) != def_chain_iterator<T>()) && \"UpTo isn't in the def chain!\""
, "/build/llvm-toolchain-snapshot-7~svn329677/include/llvm/Analysis/MemorySSA.h"
, 1217, __extension__ __PRETTY_FUNCTION__))
;
1218#endif
1219 return make_range(def_chain_iterator<T>(MA), def_chain_iterator<T>(UpTo));
1220}
1221
1222template <class T>
1223inline iterator_range<def_chain_iterator<T, true>> optimized_def_chain(T MA) {
1224 return make_range(def_chain_iterator<T, true>(MA),
1225 def_chain_iterator<T, true>(nullptr));
1226}
1227
1228} // end namespace llvm
1229
1230#endif // LLVM_ANALYSIS_MEMORYSSA_H