Bug Summary

File:lib/Analysis/MemorySSA.cpp
Warning:line 753, column 37
Called C++ object pointer is null

Annotated Source Code

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#include "llvm/Analysis/MemorySSA.h"
14#include "llvm/ADT/DenseMap.h"
15#include "llvm/ADT/DenseSet.h"
16#include "llvm/ADT/DepthFirstIterator.h"
17#include "llvm/ADT/GraphTraits.h"
18#include "llvm/ADT/PostOrderIterator.h"
19#include "llvm/ADT/STLExtras.h"
20#include "llvm/ADT/SmallBitVector.h"
21#include "llvm/ADT/SmallPtrSet.h"
22#include "llvm/ADT/SmallSet.h"
23#include "llvm/ADT/Statistic.h"
24#include "llvm/Analysis/AliasAnalysis.h"
25#include "llvm/Analysis/CFG.h"
26#include "llvm/Analysis/GlobalsModRef.h"
27#include "llvm/Analysis/IteratedDominanceFrontier.h"
28#include "llvm/Analysis/MemoryLocation.h"
29#include "llvm/Analysis/PHITransAddr.h"
30#include "llvm/IR/AssemblyAnnotationWriter.h"
31#include "llvm/IR/DataLayout.h"
32#include "llvm/IR/Dominators.h"
33#include "llvm/IR/GlobalVariable.h"
34#include "llvm/IR/IRBuilder.h"
35#include "llvm/IR/IntrinsicInst.h"
36#include "llvm/IR/LLVMContext.h"
37#include "llvm/IR/Metadata.h"
38#include "llvm/IR/Module.h"
39#include "llvm/IR/PatternMatch.h"
40#include "llvm/Support/Debug.h"
41#include "llvm/Support/FormattedStream.h"
42#include "llvm/Transforms/Scalar.h"
43#include <algorithm>
44
45#define DEBUG_TYPE"memoryssa" "memoryssa"
46using namespace llvm;
47INITIALIZE_PASS_BEGIN(MemorySSAWrapperPass, "memoryssa", "Memory SSA", false,static void *initializeMemorySSAWrapperPassPassOnce(PassRegistry
&Registry) {
48 true)static void *initializeMemorySSAWrapperPassPassOnce(PassRegistry
&Registry) {
49INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
50INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)initializeAAResultsWrapperPassPass(Registry);
51INITIALIZE_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))
; }
52 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))
; }
53
54INITIALIZE_PASS_BEGIN(MemorySSAPrinterLegacyPass, "print-memoryssa",static void *initializeMemorySSAPrinterLegacyPassPassOnce(PassRegistry
&Registry) {
55 "Memory SSA Printer", false, false)static void *initializeMemorySSAPrinterLegacyPassPassOnce(PassRegistry
&Registry) {
56INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)initializeMemorySSAWrapperPassPass(Registry);
57INITIALIZE_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
)); }
58 "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
)); }
59
60static cl::opt<unsigned> MaxCheckLimit(
61 "memssa-check-limit", cl::Hidden, cl::init(100),
62 cl::desc("The maximum number of stores/phis MemorySSA"
63 "will consider trying to walk past (default = 100)"));
64
65static cl::opt<bool>
66 VerifyMemorySSA("verify-memoryssa", cl::init(false), cl::Hidden,
67 cl::desc("Verify MemorySSA in legacy printer pass."));
68
69namespace llvm {
70/// \brief An assembly annotator class to print Memory SSA information in
71/// comments.
72class MemorySSAAnnotatedWriter : public AssemblyAnnotationWriter {
73 friend class MemorySSA;
74 const MemorySSA *MSSA;
75
76public:
77 MemorySSAAnnotatedWriter(const MemorySSA *M) : MSSA(M) {}
78
79 virtual void emitBasicBlockStartAnnot(const BasicBlock *BB,
80 formatted_raw_ostream &OS) {
81 if (MemoryAccess *MA = MSSA->getMemoryAccess(BB))
82 OS << "; " << *MA << "\n";
83 }
84
85 virtual void emitInstructionAnnot(const Instruction *I,
86 formatted_raw_ostream &OS) {
87 if (MemoryAccess *MA = MSSA->getMemoryAccess(I))
88 OS << "; " << *MA << "\n";
89 }
90};
91}
92
93namespace {
94/// Our current alias analysis API differentiates heavily between calls and
95/// non-calls, and functions called on one usually assert on the other.
96/// This class encapsulates the distinction to simplify other code that wants
97/// "Memory affecting instructions and related data" to use as a key.
98/// For example, this class is used as a densemap key in the use optimizer.
99class MemoryLocOrCall {
100public:
101 MemoryLocOrCall() : IsCall(false) {}
102 MemoryLocOrCall(MemoryUseOrDef *MUD)
103 : MemoryLocOrCall(MUD->getMemoryInst()) {}
104 MemoryLocOrCall(const MemoryUseOrDef *MUD)
105 : MemoryLocOrCall(MUD->getMemoryInst()) {}
106
107 MemoryLocOrCall(Instruction *Inst) {
108 if (ImmutableCallSite(Inst)) {
109 IsCall = true;
110 CS = ImmutableCallSite(Inst);
111 } else {
112 IsCall = false;
113 // There is no such thing as a memorylocation for a fence inst, and it is
114 // unique in that regard.
115 if (!isa<FenceInst>(Inst))
116 Loc = MemoryLocation::get(Inst);
117 }
118 }
119
120 explicit MemoryLocOrCall(const MemoryLocation &Loc)
121 : IsCall(false), Loc(Loc) {}
122
123 bool IsCall;
124 ImmutableCallSite getCS() const {
125 assert(IsCall)((IsCall) ? static_cast<void> (0) : __assert_fail ("IsCall"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 125, __PRETTY_FUNCTION__))
;
126 return CS;
127 }
128 MemoryLocation getLoc() const {
129 assert(!IsCall)((!IsCall) ? static_cast<void> (0) : __assert_fail ("!IsCall"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 129, __PRETTY_FUNCTION__))
;
130 return Loc;
131 }
132
133 bool operator==(const MemoryLocOrCall &Other) const {
134 if (IsCall != Other.IsCall)
135 return false;
136
137 if (IsCall)
138 return CS.getCalledValue() == Other.CS.getCalledValue();
139 return Loc == Other.Loc;
140 }
141
142private:
143 union {
144 ImmutableCallSite CS;
145 MemoryLocation Loc;
146 };
147};
148}
149
150namespace llvm {
151template <> struct DenseMapInfo<MemoryLocOrCall> {
152 static inline MemoryLocOrCall getEmptyKey() {
153 return MemoryLocOrCall(DenseMapInfo<MemoryLocation>::getEmptyKey());
154 }
155 static inline MemoryLocOrCall getTombstoneKey() {
156 return MemoryLocOrCall(DenseMapInfo<MemoryLocation>::getTombstoneKey());
157 }
158 static unsigned getHashValue(const MemoryLocOrCall &MLOC) {
159 if (MLOC.IsCall)
160 return hash_combine(MLOC.IsCall,
161 DenseMapInfo<const Value *>::getHashValue(
162 MLOC.getCS().getCalledValue()));
163 return hash_combine(
164 MLOC.IsCall, DenseMapInfo<MemoryLocation>::getHashValue(MLOC.getLoc()));
165 }
166 static bool isEqual(const MemoryLocOrCall &LHS, const MemoryLocOrCall &RHS) {
167 return LHS == RHS;
168 }
169};
170
171enum class Reorderability { Always, IfNoAlias, Never };
172
173/// This does one-way checks to see if Use could theoretically be hoisted above
174/// MayClobber. This will not check the other way around.
175///
176/// This assumes that, for the purposes of MemorySSA, Use comes directly after
177/// MayClobber, with no potentially clobbering operations in between them.
178/// (Where potentially clobbering ops are memory barriers, aliased stores, etc.)
179static Reorderability getLoadReorderability(const LoadInst *Use,
180 const LoadInst *MayClobber) {
181 bool VolatileUse = Use->isVolatile();
182 bool VolatileClobber = MayClobber->isVolatile();
183 // Volatile operations may never be reordered with other volatile operations.
184 if (VolatileUse && VolatileClobber)
185 return Reorderability::Never;
186
187 // The lang ref allows reordering of volatile and non-volatile operations.
188 // Whether an aliasing nonvolatile load and volatile load can be reordered,
189 // though, is ambiguous. Because it may not be best to exploit this ambiguity,
190 // we only allow volatile/non-volatile reordering if the volatile and
191 // non-volatile operations don't alias.
192 Reorderability Result = VolatileUse || VolatileClobber
193 ? Reorderability::IfNoAlias
194 : Reorderability::Always;
195
196 // If a load is seq_cst, it cannot be moved above other loads. If its ordering
197 // is weaker, it can be moved above other loads. We just need to be sure that
198 // MayClobber isn't an acquire load, because loads can't be moved above
199 // acquire loads.
200 //
201 // Note that this explicitly *does* allow the free reordering of monotonic (or
202 // weaker) loads of the same address.
203 bool SeqCstUse = Use->getOrdering() == AtomicOrdering::SequentiallyConsistent;
204 bool MayClobberIsAcquire = isAtLeastOrStrongerThan(MayClobber->getOrdering(),
205 AtomicOrdering::Acquire);
206 if (SeqCstUse || MayClobberIsAcquire)
207 return Reorderability::Never;
208 return Result;
209}
210
211static bool instructionClobbersQuery(MemoryDef *MD,
212 const MemoryLocation &UseLoc,
213 const Instruction *UseInst,
214 AliasAnalysis &AA) {
215 Instruction *DefInst = MD->getMemoryInst();
216 assert(DefInst && "Defining instruction not actually an instruction")((DefInst && "Defining instruction not actually an instruction"
) ? static_cast<void> (0) : __assert_fail ("DefInst && \"Defining instruction not actually an instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 216, __PRETTY_FUNCTION__))
;
217 ImmutableCallSite UseCS(UseInst);
218
219 if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(DefInst)) {
220 // These intrinsics will show up as affecting memory, but they are just
221 // markers.
222 switch (II->getIntrinsicID()) {
223 case Intrinsic::lifetime_start:
224 if (UseCS)
225 return false;
226 return AA.isMustAlias(MemoryLocation(II->getArgOperand(1)), UseLoc);
227 case Intrinsic::lifetime_end:
228 case Intrinsic::invariant_start:
229 case Intrinsic::invariant_end:
230 case Intrinsic::assume:
231 return false;
232 default:
233 break;
234 }
235 }
236
237 if (UseCS) {
238 ModRefInfo I = AA.getModRefInfo(DefInst, UseCS);
239 return I != MRI_NoModRef;
240 }
241
242 if (auto *DefLoad = dyn_cast<LoadInst>(DefInst)) {
243 if (auto *UseLoad = dyn_cast<LoadInst>(UseInst)) {
244 switch (getLoadReorderability(UseLoad, DefLoad)) {
245 case Reorderability::Always:
246 return false;
247 case Reorderability::Never:
248 return true;
249 case Reorderability::IfNoAlias:
250 return !AA.isNoAlias(UseLoc, MemoryLocation::get(DefLoad));
251 }
252 }
253 }
254
255 return AA.getModRefInfo(DefInst, UseLoc) & MRI_Mod;
256}
257
258static bool instructionClobbersQuery(MemoryDef *MD, const MemoryUseOrDef *MU,
259 const MemoryLocOrCall &UseMLOC,
260 AliasAnalysis &AA) {
261 // FIXME: This is a temporary hack to allow a single instructionClobbersQuery
262 // to exist while MemoryLocOrCall is pushed through places.
263 if (UseMLOC.IsCall)
264 return instructionClobbersQuery(MD, MemoryLocation(), MU->getMemoryInst(),
265 AA);
266 return instructionClobbersQuery(MD, UseMLOC.getLoc(), MU->getMemoryInst(),
267 AA);
268}
269
270// Return true when MD may alias MU, return false otherwise.
271bool MemorySSAUtil::defClobbersUseOrDef(MemoryDef *MD, const MemoryUseOrDef *MU,
272 AliasAnalysis &AA) {
273 return instructionClobbersQuery(MD, MU, MemoryLocOrCall(MU), AA);
274}
275}
276
277namespace {
278struct UpwardsMemoryQuery {
279 // True if our original query started off as a call
280 bool IsCall;
281 // The pointer location we started the query with. This will be empty if
282 // IsCall is true.
283 MemoryLocation StartingLoc;
284 // This is the instruction we were querying about.
285 const Instruction *Inst;
286 // The MemoryAccess we actually got called with, used to test local domination
287 const MemoryAccess *OriginalAccess;
288
289 UpwardsMemoryQuery()
290 : IsCall(false), Inst(nullptr), OriginalAccess(nullptr) {}
291
292 UpwardsMemoryQuery(const Instruction *Inst, const MemoryAccess *Access)
293 : IsCall(ImmutableCallSite(Inst)), Inst(Inst), OriginalAccess(Access) {
294 if (!IsCall)
295 StartingLoc = MemoryLocation::get(Inst);
296 }
297};
298
299static bool lifetimeEndsAt(MemoryDef *MD, const MemoryLocation &Loc,
300 AliasAnalysis &AA) {
301 Instruction *Inst = MD->getMemoryInst();
302 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
303 switch (II->getIntrinsicID()) {
304 case Intrinsic::lifetime_end:
305 return AA.isMustAlias(MemoryLocation(II->getArgOperand(1)), Loc);
306 default:
307 return false;
308 }
309 }
310 return false;
311}
312
313static bool isUseTriviallyOptimizableToLiveOnEntry(AliasAnalysis &AA,
314 const Instruction *I) {
315 // If the memory can't be changed, then loads of the memory can't be
316 // clobbered.
317 //
318 // FIXME: We should handle invariant groups, as well. It's a bit harder,
319 // because we need to pay close attention to invariant group barriers.
320 return isa<LoadInst>(I) && (I->getMetadata(LLVMContext::MD_invariant_load) ||
321 AA.pointsToConstantMemory(cast<LoadInst>(I)->
322 getPointerOperand()));
323}
324
325/// Verifies that `Start` is clobbered by `ClobberAt`, and that nothing
326/// inbetween `Start` and `ClobberAt` can clobbers `Start`.
327///
328/// This is meant to be as simple and self-contained as possible. Because it
329/// uses no cache, etc., it can be relatively expensive.
330///
331/// \param Start The MemoryAccess that we want to walk from.
332/// \param ClobberAt A clobber for Start.
333/// \param StartLoc The MemoryLocation for Start.
334/// \param MSSA The MemorySSA isntance that Start and ClobberAt belong to.
335/// \param Query The UpwardsMemoryQuery we used for our search.
336/// \param AA The AliasAnalysis we used for our search.
337static void LLVM_ATTRIBUTE_UNUSED__attribute__((__unused__))
338checkClobberSanity(MemoryAccess *Start, MemoryAccess *ClobberAt,
339 const MemoryLocation &StartLoc, const MemorySSA &MSSA,
340 const UpwardsMemoryQuery &Query, AliasAnalysis &AA) {
341 assert(MSSA.dominates(ClobberAt, Start) && "Clobber doesn't dominate start?")((MSSA.dominates(ClobberAt, Start) && "Clobber doesn't dominate start?"
) ? static_cast<void> (0) : __assert_fail ("MSSA.dominates(ClobberAt, Start) && \"Clobber doesn't dominate start?\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 341, __PRETTY_FUNCTION__))
;
342
343 if (MSSA.isLiveOnEntryDef(Start)) {
344 assert(MSSA.isLiveOnEntryDef(ClobberAt) &&((MSSA.isLiveOnEntryDef(ClobberAt) && "liveOnEntry must clobber itself"
) ? static_cast<void> (0) : __assert_fail ("MSSA.isLiveOnEntryDef(ClobberAt) && \"liveOnEntry must clobber itself\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 345, __PRETTY_FUNCTION__))
345 "liveOnEntry must clobber itself")((MSSA.isLiveOnEntryDef(ClobberAt) && "liveOnEntry must clobber itself"
) ? static_cast<void> (0) : __assert_fail ("MSSA.isLiveOnEntryDef(ClobberAt) && \"liveOnEntry must clobber itself\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 345, __PRETTY_FUNCTION__))
;
346 return;
347 }
348
349 bool FoundClobber = false;
350 DenseSet<MemoryAccessPair> VisitedPhis;
351 SmallVector<MemoryAccessPair, 8> Worklist;
352 Worklist.emplace_back(Start, StartLoc);
353 // Walk all paths from Start to ClobberAt, while looking for clobbers. If one
354 // is found, complain.
355 while (!Worklist.empty()) {
356 MemoryAccessPair MAP = Worklist.pop_back_val();
357 // All we care about is that nothing from Start to ClobberAt clobbers Start.
358 // We learn nothing from revisiting nodes.
359 if (!VisitedPhis.insert(MAP).second)
360 continue;
361
362 for (MemoryAccess *MA : def_chain(MAP.first)) {
363 if (MA == ClobberAt) {
364 if (auto *MD = dyn_cast<MemoryDef>(MA)) {
365 // instructionClobbersQuery isn't essentially free, so don't use `|=`,
366 // since it won't let us short-circuit.
367 //
368 // Also, note that this can't be hoisted out of the `Worklist` loop,
369 // since MD may only act as a clobber for 1 of N MemoryLocations.
370 FoundClobber =
371 FoundClobber || MSSA.isLiveOnEntryDef(MD) ||
372 instructionClobbersQuery(MD, MAP.second, Query.Inst, AA);
373 }
374 break;
375 }
376
377 // We should never hit liveOnEntry, unless it's the clobber.
378 assert(!MSSA.isLiveOnEntryDef(MA) && "Hit liveOnEntry before clobber?")((!MSSA.isLiveOnEntryDef(MA) && "Hit liveOnEntry before clobber?"
) ? static_cast<void> (0) : __assert_fail ("!MSSA.isLiveOnEntryDef(MA) && \"Hit liveOnEntry before clobber?\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 378, __PRETTY_FUNCTION__))
;
379
380 if (auto *MD = dyn_cast<MemoryDef>(MA)) {
381 (void)MD;
382 assert(!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) &&((!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) &&
"Found clobber before reaching ClobberAt!") ? static_cast<
void> (0) : __assert_fail ("!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) && \"Found clobber before reaching ClobberAt!\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 383, __PRETTY_FUNCTION__))
383 "Found clobber before reaching ClobberAt!")((!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) &&
"Found clobber before reaching ClobberAt!") ? static_cast<
void> (0) : __assert_fail ("!instructionClobbersQuery(MD, MAP.second, Query.Inst, AA) && \"Found clobber before reaching ClobberAt!\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 383, __PRETTY_FUNCTION__))
;
384 continue;
385 }
386
387 assert(isa<MemoryPhi>(MA))((isa<MemoryPhi>(MA)) ? static_cast<void> (0) : __assert_fail
("isa<MemoryPhi>(MA)", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 387, __PRETTY_FUNCTION__))
;
388 Worklist.append(upward_defs_begin({MA, MAP.second}), upward_defs_end());
389 }
390 }
391
392 // If ClobberAt is a MemoryPhi, we can assume something above it acted as a
393 // clobber. Otherwise, `ClobberAt` should've acted as a clobber at some point.
394 assert((isa<MemoryPhi>(ClobberAt) || FoundClobber) &&(((isa<MemoryPhi>(ClobberAt) || FoundClobber) &&
"ClobberAt never acted as a clobber") ? static_cast<void>
(0) : __assert_fail ("(isa<MemoryPhi>(ClobberAt) || FoundClobber) && \"ClobberAt never acted as a clobber\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 395, __PRETTY_FUNCTION__))
395 "ClobberAt never acted as a clobber")(((isa<MemoryPhi>(ClobberAt) || FoundClobber) &&
"ClobberAt never acted as a clobber") ? static_cast<void>
(0) : __assert_fail ("(isa<MemoryPhi>(ClobberAt) || FoundClobber) && \"ClobberAt never acted as a clobber\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 395, __PRETTY_FUNCTION__))
;
396}
397
398/// Our algorithm for walking (and trying to optimize) clobbers, all wrapped up
399/// in one class.
400class ClobberWalker {
401 /// Save a few bytes by using unsigned instead of size_t.
402 using ListIndex = unsigned;
403
404 /// Represents a span of contiguous MemoryDefs, potentially ending in a
405 /// MemoryPhi.
406 struct DefPath {
407 MemoryLocation Loc;
408 // Note that, because we always walk in reverse, Last will always dominate
409 // First. Also note that First and Last are inclusive.
410 MemoryAccess *First;
411 MemoryAccess *Last;
412 Optional<ListIndex> Previous;
413
414 DefPath(const MemoryLocation &Loc, MemoryAccess *First, MemoryAccess *Last,
415 Optional<ListIndex> Previous)
416 : Loc(Loc), First(First), Last(Last), Previous(Previous) {}
417
418 DefPath(const MemoryLocation &Loc, MemoryAccess *Init,
419 Optional<ListIndex> Previous)
420 : DefPath(Loc, Init, Init, Previous) {}
421 };
422
423 const MemorySSA &MSSA;
424 AliasAnalysis &AA;
425 DominatorTree &DT;
426 UpwardsMemoryQuery *Query;
427
428 // Phi optimization bookkeeping
429 SmallVector<DefPath, 32> Paths;
430 DenseSet<ConstMemoryAccessPair> VisitedPhis;
431
432 /// Find the nearest def or phi that `From` can legally be optimized to.
433 const MemoryAccess *getWalkTarget(const MemoryPhi *From) const {
434 assert(From->getNumOperands() && "Phi with no operands?")((From->getNumOperands() && "Phi with no operands?"
) ? static_cast<void> (0) : __assert_fail ("From->getNumOperands() && \"Phi with no operands?\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 434, __PRETTY_FUNCTION__))
;
435
436 BasicBlock *BB = From->getBlock();
437 MemoryAccess *Result = MSSA.getLiveOnEntryDef();
438 DomTreeNode *Node = DT.getNode(BB);
439 while ((Node = Node->getIDom())) {
440 auto *Defs = MSSA.getBlockDefs(Node->getBlock());
441 if (Defs)
442 return &*Defs->rbegin();
443 }
444 return Result;
445 }
446
447 /// Result of calling walkToPhiOrClobber.
448 struct UpwardsWalkResult {
449 /// The "Result" of the walk. Either a clobber, the last thing we walked, or
450 /// both.
451 MemoryAccess *Result;
452 bool IsKnownClobber;
453 };
454
455 /// Walk to the next Phi or Clobber in the def chain starting at Desc.Last.
456 /// This will update Desc.Last as it walks. It will (optionally) also stop at
457 /// StopAt.
458 ///
459 /// This does not test for whether StopAt is a clobber
460 UpwardsWalkResult
461 walkToPhiOrClobber(DefPath &Desc,
462 const MemoryAccess *StopAt = nullptr) const {
463 assert(!isa<MemoryUse>(Desc.Last) && "Uses don't exist in my world")((!isa<MemoryUse>(Desc.Last) && "Uses don't exist in my world"
) ? static_cast<void> (0) : __assert_fail ("!isa<MemoryUse>(Desc.Last) && \"Uses don't exist in my world\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 463, __PRETTY_FUNCTION__))
;
464
465 for (MemoryAccess *Current : def_chain(Desc.Last)) {
466 Desc.Last = Current;
467 if (Current == StopAt)
468 return {Current, false};
469
470 if (auto *MD = dyn_cast<MemoryDef>(Current))
471 if (MSSA.isLiveOnEntryDef(MD) ||
472 instructionClobbersQuery(MD, Desc.Loc, Query->Inst, AA))
473 return {MD, true};
474 }
475
476 assert(isa<MemoryPhi>(Desc.Last) &&((isa<MemoryPhi>(Desc.Last) && "Ended at a non-clobber that's not a phi?"
) ? static_cast<void> (0) : __assert_fail ("isa<MemoryPhi>(Desc.Last) && \"Ended at a non-clobber that's not a phi?\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 477, __PRETTY_FUNCTION__))
477 "Ended at a non-clobber that's not a phi?")((isa<MemoryPhi>(Desc.Last) && "Ended at a non-clobber that's not a phi?"
) ? static_cast<void> (0) : __assert_fail ("isa<MemoryPhi>(Desc.Last) && \"Ended at a non-clobber that's not a phi?\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 477, __PRETTY_FUNCTION__))
;
478 return {Desc.Last, false};
479 }
480
481 void addSearches(MemoryPhi *Phi, SmallVectorImpl<ListIndex> &PausedSearches,
482 ListIndex PriorNode) {
483 auto UpwardDefs = make_range(upward_defs_begin({Phi, Paths[PriorNode].Loc}),
484 upward_defs_end());
485 for (const MemoryAccessPair &P : UpwardDefs) {
486 PausedSearches.push_back(Paths.size());
487 Paths.emplace_back(P.second, P.first, PriorNode);
488 }
489 }
490
491 /// Represents a search that terminated after finding a clobber. This clobber
492 /// may or may not be present in the path of defs from LastNode..SearchStart,
493 /// since it may have been retrieved from cache.
494 struct TerminatedPath {
495 MemoryAccess *Clobber;
496 ListIndex LastNode;
497 };
498
499 /// Get an access that keeps us from optimizing to the given phi.
500 ///
501 /// PausedSearches is an array of indices into the Paths array. Its incoming
502 /// value is the indices of searches that stopped at the last phi optimization
503 /// target. It's left in an unspecified state.
504 ///
505 /// If this returns None, NewPaused is a vector of searches that terminated
506 /// at StopWhere. Otherwise, NewPaused is left in an unspecified state.
507 Optional<TerminatedPath>
508 getBlockingAccess(const MemoryAccess *StopWhere,
509 SmallVectorImpl<ListIndex> &PausedSearches,
510 SmallVectorImpl<ListIndex> &NewPaused,
511 SmallVectorImpl<TerminatedPath> &Terminated) {
512 assert(!PausedSearches.empty() && "No searches to continue?")((!PausedSearches.empty() && "No searches to continue?"
) ? static_cast<void> (0) : __assert_fail ("!PausedSearches.empty() && \"No searches to continue?\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 512, __PRETTY_FUNCTION__))
;
513
514 // BFS vs DFS really doesn't make a difference here, so just do a DFS with
515 // PausedSearches as our stack.
516 while (!PausedSearches.empty()) {
517 ListIndex PathIndex = PausedSearches.pop_back_val();
518 DefPath &Node = Paths[PathIndex];
519
520 // If we've already visited this path with this MemoryLocation, we don't
521 // need to do so again.
522 //
523 // NOTE: That we just drop these paths on the ground makes caching
524 // behavior sporadic. e.g. given a diamond:
525 // A
526 // B C
527 // D
528 //
529 // ...If we walk D, B, A, C, we'll only cache the result of phi
530 // optimization for A, B, and D; C will be skipped because it dies here.
531 // This arguably isn't the worst thing ever, since:
532 // - We generally query things in a top-down order, so if we got below D
533 // without needing cache entries for {C, MemLoc}, then chances are
534 // that those cache entries would end up ultimately unused.
535 // - We still cache things for A, so C only needs to walk up a bit.
536 // If this behavior becomes problematic, we can fix without a ton of extra
537 // work.
538 if (!VisitedPhis.insert({Node.Last, Node.Loc}).second)
539 continue;
540
541 UpwardsWalkResult Res = walkToPhiOrClobber(Node, /*StopAt=*/StopWhere);
542 if (Res.IsKnownClobber) {
543 assert(Res.Result != StopWhere)((Res.Result != StopWhere) ? static_cast<void> (0) : __assert_fail
("Res.Result != StopWhere", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 543, __PRETTY_FUNCTION__))
;
544 // If this wasn't a cache hit, we hit a clobber when walking. That's a
545 // failure.
546 TerminatedPath Term{Res.Result, PathIndex};
547 if (!MSSA.dominates(Res.Result, StopWhere))
548 return Term;
549
550 // Otherwise, it's a valid thing to potentially optimize to.
551 Terminated.push_back(Term);
552 continue;
553 }
554
555 if (Res.Result == StopWhere) {
556 // We've hit our target. Save this path off for if we want to continue
557 // walking.
558 NewPaused.push_back(PathIndex);
559 continue;
560 }
561
562 assert(!MSSA.isLiveOnEntryDef(Res.Result) && "liveOnEntry is a clobber")((!MSSA.isLiveOnEntryDef(Res.Result) && "liveOnEntry is a clobber"
) ? static_cast<void> (0) : __assert_fail ("!MSSA.isLiveOnEntryDef(Res.Result) && \"liveOnEntry is a clobber\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 562, __PRETTY_FUNCTION__))
;
563 addSearches(cast<MemoryPhi>(Res.Result), PausedSearches, PathIndex);
564 }
565
566 return None;
567 }
568
569 template <typename T, typename Walker>
570 struct generic_def_path_iterator
571 : public iterator_facade_base<generic_def_path_iterator<T, Walker>,
572 std::forward_iterator_tag, T *> {
573 generic_def_path_iterator() : W(nullptr), N(None) {}
574 generic_def_path_iterator(Walker *W, ListIndex N) : W(W), N(N) {}
575
576 T &operator*() const { return curNode(); }
577
578 generic_def_path_iterator &operator++() {
579 N = curNode().Previous;
580 return *this;
581 }
582
583 bool operator==(const generic_def_path_iterator &O) const {
584 if (N.hasValue() != O.N.hasValue())
585 return false;
586 return !N.hasValue() || *N == *O.N;
587 }
588
589 private:
590 T &curNode() const { return W->Paths[*N]; }
591
592 Walker *W;
593 Optional<ListIndex> N;
594 };
595
596 using def_path_iterator = generic_def_path_iterator<DefPath, ClobberWalker>;
597 using const_def_path_iterator =
598 generic_def_path_iterator<const DefPath, const ClobberWalker>;
599
600 iterator_range<def_path_iterator> def_path(ListIndex From) {
601 return make_range(def_path_iterator(this, From), def_path_iterator());
602 }
603
604 iterator_range<const_def_path_iterator> const_def_path(ListIndex From) const {
605 return make_range(const_def_path_iterator(this, From),
606 const_def_path_iterator());
607 }
608
609 struct OptznResult {
610 /// The path that contains our result.
611 TerminatedPath PrimaryClobber;
612 /// The paths that we can legally cache back from, but that aren't
613 /// necessarily the result of the Phi optimization.
614 SmallVector<TerminatedPath, 4> OtherClobbers;
615 };
616
617 ListIndex defPathIndex(const DefPath &N) const {
618 // The assert looks nicer if we don't need to do &N
619 const DefPath *NP = &N;
620 assert(!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() &&((!Paths.empty() && NP >= &Paths.front() &&
NP <= &Paths.back() && "Out of bounds DefPath!"
) ? static_cast<void> (0) : __assert_fail ("!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() && \"Out of bounds DefPath!\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 621, __PRETTY_FUNCTION__))
621 "Out of bounds DefPath!")((!Paths.empty() && NP >= &Paths.front() &&
NP <= &Paths.back() && "Out of bounds DefPath!"
) ? static_cast<void> (0) : __assert_fail ("!Paths.empty() && NP >= &Paths.front() && NP <= &Paths.back() && \"Out of bounds DefPath!\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 621, __PRETTY_FUNCTION__))
;
622 return NP - &Paths.front();
623 }
624
625 /// Try to optimize a phi as best as we can. Returns a SmallVector of Paths
626 /// that act as legal clobbers. Note that this won't return *all* clobbers.
627 ///
628 /// Phi optimization algorithm tl;dr:
629 /// - Find the earliest def/phi, A, we can optimize to
630 /// - Find if all paths from the starting memory access ultimately reach A
631 /// - If not, optimization isn't possible.
632 /// - Otherwise, walk from A to another clobber or phi, A'.
633 /// - If A' is a def, we're done.
634 /// - If A' is a phi, try to optimize it.
635 ///
636 /// A path is a series of {MemoryAccess, MemoryLocation} pairs. A path
637 /// terminates when a MemoryAccess that clobbers said MemoryLocation is found.
638 OptznResult tryOptimizePhi(MemoryPhi *Phi, MemoryAccess *Start,
639 const MemoryLocation &Loc) {
640 assert(Paths.empty() && VisitedPhis.empty() &&((Paths.empty() && VisitedPhis.empty() && "Reset the optimization state."
) ? static_cast<void> (0) : __assert_fail ("Paths.empty() && VisitedPhis.empty() && \"Reset the optimization state.\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 641, __PRETTY_FUNCTION__))
641 "Reset the optimization state.")((Paths.empty() && VisitedPhis.empty() && "Reset the optimization state."
) ? static_cast<void> (0) : __assert_fail ("Paths.empty() && VisitedPhis.empty() && \"Reset the optimization state.\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 641, __PRETTY_FUNCTION__))
;
642
643 Paths.emplace_back(Loc, Start, Phi, None);
644 // Stores how many "valid" optimization nodes we had prior to calling
645 // addSearches/getBlockingAccess. Necessary for caching if we had a blocker.
646 auto PriorPathsSize = Paths.size();
647
648 SmallVector<ListIndex, 16> PausedSearches;
649 SmallVector<ListIndex, 8> NewPaused;
650 SmallVector<TerminatedPath, 4> TerminatedPaths;
651
652 addSearches(Phi, PausedSearches, 0);
653
654 // Moves the TerminatedPath with the "most dominated" Clobber to the end of
655 // Paths.
656 auto MoveDominatedPathToEnd = [&](SmallVectorImpl<TerminatedPath> &Paths) {
657 assert(!Paths.empty() && "Need a path to move")((!Paths.empty() && "Need a path to move") ? static_cast
<void> (0) : __assert_fail ("!Paths.empty() && \"Need a path to move\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 657, __PRETTY_FUNCTION__))
;
658 auto Dom = Paths.begin();
659 for (auto I = std::next(Dom), E = Paths.end(); I != E; ++I)
660 if (!MSSA.dominates(I->Clobber, Dom->Clobber))
661 Dom = I;
662 auto Last = Paths.end() - 1;
663 if (Last != Dom)
664 std::iter_swap(Last, Dom);
665 };
666
667 MemoryPhi *Current = Phi;
668 while (1) {
1
Loop condition is true. Entering loop body
669 assert(!MSSA.isLiveOnEntryDef(Current) &&((!MSSA.isLiveOnEntryDef(Current) && "liveOnEntry wasn't treated as a clobber?"
) ? static_cast<void> (0) : __assert_fail ("!MSSA.isLiveOnEntryDef(Current) && \"liveOnEntry wasn't treated as a clobber?\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 670, __PRETTY_FUNCTION__))
670 "liveOnEntry wasn't treated as a clobber?")((!MSSA.isLiveOnEntryDef(Current) && "liveOnEntry wasn't treated as a clobber?"
) ? static_cast<void> (0) : __assert_fail ("!MSSA.isLiveOnEntryDef(Current) && \"liveOnEntry wasn't treated as a clobber?\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 670, __PRETTY_FUNCTION__))
;
671
672 const auto *Target = getWalkTarget(Current);
673 // If a TerminatedPath doesn't dominate Target, then it wasn't a legal
674 // optimization for the prior phi.
675 assert(all_of(TerminatedPaths, [&](const TerminatedPath &P) {((all_of(TerminatedPaths, [&](const TerminatedPath &P
) { return MSSA.dominates(P.Clobber, Target); })) ? static_cast
<void> (0) : __assert_fail ("all_of(TerminatedPaths, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target); })"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 677, __PRETTY_FUNCTION__))
676 return MSSA.dominates(P.Clobber, Target);((all_of(TerminatedPaths, [&](const TerminatedPath &P
) { return MSSA.dominates(P.Clobber, Target); })) ? static_cast
<void> (0) : __assert_fail ("all_of(TerminatedPaths, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target); })"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 677, __PRETTY_FUNCTION__))
677 }))((all_of(TerminatedPaths, [&](const TerminatedPath &P
) { return MSSA.dominates(P.Clobber, Target); })) ? static_cast
<void> (0) : __assert_fail ("all_of(TerminatedPaths, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, Target); })"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 677, __PRETTY_FUNCTION__))
;
678
679 // FIXME: This is broken, because the Blocker may be reported to be
680 // liveOnEntry, and we'll happily wait for that to disappear (read: never)
681 // For the moment, this is fine, since we do nothing with blocker info.
682 if (Optional<TerminatedPath> Blocker = getBlockingAccess(
2
Taking false branch
683 Target, PausedSearches, NewPaused, TerminatedPaths)) {
684
685 // Find the node we started at. We can't search based on N->Last, since
686 // we may have gone around a loop with a different MemoryLocation.
687 auto Iter = find_if(def_path(Blocker->LastNode), [&](const DefPath &N) {
688 return defPathIndex(N) < PriorPathsSize;
689 });
690 assert(Iter != def_path_iterator())((Iter != def_path_iterator()) ? static_cast<void> (0) :
__assert_fail ("Iter != def_path_iterator()", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 690, __PRETTY_FUNCTION__))
;
691
692 DefPath &CurNode = *Iter;
693 assert(CurNode.Last == Current)((CurNode.Last == Current) ? static_cast<void> (0) : __assert_fail
("CurNode.Last == Current", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 693, __PRETTY_FUNCTION__))
;
694
695 // Two things:
696 // A. We can't reliably cache all of NewPaused back. Consider a case
697 // where we have two paths in NewPaused; one of which can't optimize
698 // above this phi, whereas the other can. If we cache the second path
699 // back, we'll end up with suboptimal cache entries. We can handle
700 // cases like this a bit better when we either try to find all
701 // clobbers that block phi optimization, or when our cache starts
702 // supporting unfinished searches.
703 // B. We can't reliably cache TerminatedPaths back here without doing
704 // extra checks; consider a case like:
705 // T
706 // / \
707 // D C
708 // \ /
709 // S
710 // Where T is our target, C is a node with a clobber on it, D is a
711 // diamond (with a clobber *only* on the left or right node, N), and
712 // S is our start. Say we walk to D, through the node opposite N
713 // (read: ignoring the clobber), and see a cache entry in the top
714 // node of D. That cache entry gets put into TerminatedPaths. We then
715 // walk up to C (N is later in our worklist), find the clobber, and
716 // quit. If we append TerminatedPaths to OtherClobbers, we'll cache
717 // the bottom part of D to the cached clobber, ignoring the clobber
718 // in N. Again, this problem goes away if we start tracking all
719 // blockers for a given phi optimization.
720 TerminatedPath Result{CurNode.Last, defPathIndex(CurNode)};
721 return {Result, {}};
722 }
723
724 // If there's nothing left to search, then all paths led to valid clobbers
725 // that we got from our cache; pick the nearest to the start, and allow
726 // the rest to be cached back.
727 if (NewPaused.empty()) {
3
Taking false branch
728 MoveDominatedPathToEnd(TerminatedPaths);
729 TerminatedPath Result = TerminatedPaths.pop_back_val();
730 return {Result, std::move(TerminatedPaths)};
731 }
732
733 MemoryAccess *DefChainEnd = nullptr;
4
'DefChainEnd' initialized to a null pointer value
734 SmallVector<TerminatedPath, 4> Clobbers;
735 for (ListIndex Paused : NewPaused) {
5
Assuming '__begin' is equal to '__end'
736 UpwardsWalkResult WR = walkToPhiOrClobber(Paths[Paused]);
737 if (WR.IsKnownClobber)
738 Clobbers.push_back({WR.Result, Paused});
739 else
740 // Micro-opt: If we hit the end of the chain, save it.
741 DefChainEnd = WR.Result;
742 }
743
744 if (!TerminatedPaths.empty()) {
6
Taking true branch
745 // If we couldn't find the dominating phi/liveOnEntry in the above loop,
746 // do it now.
747 if (!DefChainEnd)
7
Taking true branch
748 for (auto *MA : def_chain(const_cast<MemoryAccess *>(Target)))
749 DefChainEnd = MA;
750
751 // If any of the terminated paths don't dominate the phi we'll try to
752 // optimize, we need to figure out what they are and quit.
753 const BasicBlock *ChainBB = DefChainEnd->getBlock();
8
Called C++ object pointer is null
754 for (const TerminatedPath &TP : TerminatedPaths) {
755 // Because we know that DefChainEnd is as "high" as we can go, we
756 // don't need local dominance checks; BB dominance is sufficient.
757 if (DT.dominates(ChainBB, TP.Clobber->getBlock()))
758 Clobbers.push_back(TP);
759 }
760 }
761
762 // If we have clobbers in the def chain, find the one closest to Current
763 // and quit.
764 if (!Clobbers.empty()) {
765 MoveDominatedPathToEnd(Clobbers);
766 TerminatedPath Result = Clobbers.pop_back_val();
767 return {Result, std::move(Clobbers)};
768 }
769
770 assert(all_of(NewPaused,((all_of(NewPaused, [&](ListIndex I) { return Paths[I].Last
== DefChainEnd; })) ? static_cast<void> (0) : __assert_fail
("all_of(NewPaused, [&](ListIndex I) { return Paths[I].Last == DefChainEnd; })"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 771, __PRETTY_FUNCTION__))
771 [&](ListIndex I) { return Paths[I].Last == DefChainEnd; }))((all_of(NewPaused, [&](ListIndex I) { return Paths[I].Last
== DefChainEnd; })) ? static_cast<void> (0) : __assert_fail
("all_of(NewPaused, [&](ListIndex I) { return Paths[I].Last == DefChainEnd; })"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 771, __PRETTY_FUNCTION__))
;
772
773 // Because liveOnEntry is a clobber, this must be a phi.
774 auto *DefChainPhi = cast<MemoryPhi>(DefChainEnd);
775
776 PriorPathsSize = Paths.size();
777 PausedSearches.clear();
778 for (ListIndex I : NewPaused)
779 addSearches(DefChainPhi, PausedSearches, I);
780 NewPaused.clear();
781
782 Current = DefChainPhi;
783 }
784 }
785
786 void verifyOptResult(const OptznResult &R) const {
787 assert(all_of(R.OtherClobbers, [&](const TerminatedPath &P) {((all_of(R.OtherClobbers, [&](const TerminatedPath &P
) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber
); })) ? static_cast<void> (0) : __assert_fail ("all_of(R.OtherClobbers, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber); })"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 789, __PRETTY_FUNCTION__))
788 return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber);((all_of(R.OtherClobbers, [&](const TerminatedPath &P
) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber
); })) ? static_cast<void> (0) : __assert_fail ("all_of(R.OtherClobbers, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber); })"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 789, __PRETTY_FUNCTION__))
789 }))((all_of(R.OtherClobbers, [&](const TerminatedPath &P
) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber
); })) ? static_cast<void> (0) : __assert_fail ("all_of(R.OtherClobbers, [&](const TerminatedPath &P) { return MSSA.dominates(P.Clobber, R.PrimaryClobber.Clobber); })"
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 789, __PRETTY_FUNCTION__))
;
790 }
791
792 void resetPhiOptznState() {
793 Paths.clear();
794 VisitedPhis.clear();
795 }
796
797public:
798 ClobberWalker(const MemorySSA &MSSA, AliasAnalysis &AA, DominatorTree &DT)
799 : MSSA(MSSA), AA(AA), DT(DT) {}
800
801 void reset() {}
802
803 /// Finds the nearest clobber for the given query, optimizing phis if
804 /// possible.
805 MemoryAccess *findClobber(MemoryAccess *Start, UpwardsMemoryQuery &Q) {
806 Query = &Q;
807
808 MemoryAccess *Current = Start;
809 // This walker pretends uses don't exist. If we're handed one, silently grab
810 // its def. (This has the nice side-effect of ensuring we never cache uses)
811 if (auto *MU = dyn_cast<MemoryUse>(Start))
812 Current = MU->getDefiningAccess();
813
814 DefPath FirstDesc(Q.StartingLoc, Current, Current, None);
815 // Fast path for the overly-common case (no crazy phi optimization
816 // necessary)
817 UpwardsWalkResult WalkResult = walkToPhiOrClobber(FirstDesc);
818 MemoryAccess *Result;
819 if (WalkResult.IsKnownClobber) {
820 Result = WalkResult.Result;
821 } else {
822 OptznResult OptRes = tryOptimizePhi(cast<MemoryPhi>(FirstDesc.Last),
823 Current, Q.StartingLoc);
824 verifyOptResult(OptRes);
825 resetPhiOptznState();
826 Result = OptRes.PrimaryClobber.Clobber;
827 }
828
829#ifdef EXPENSIVE_CHECKS
830 checkClobberSanity(Current, Result, Q.StartingLoc, MSSA, Q, AA);
831#endif
832 return Result;
833 }
834
835 void verify(const MemorySSA *MSSA) { assert(MSSA == &this->MSSA)((MSSA == &this->MSSA) ? static_cast<void> (0) :
__assert_fail ("MSSA == &this->MSSA", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 835, __PRETTY_FUNCTION__))
; }
836};
837
838struct RenamePassData {
839 DomTreeNode *DTN;
840 DomTreeNode::const_iterator ChildIt;
841 MemoryAccess *IncomingVal;
842
843 RenamePassData(DomTreeNode *D, DomTreeNode::const_iterator It,
844 MemoryAccess *M)
845 : DTN(D), ChildIt(It), IncomingVal(M) {}
846 void swap(RenamePassData &RHS) {
847 std::swap(DTN, RHS.DTN);
848 std::swap(ChildIt, RHS.ChildIt);
849 std::swap(IncomingVal, RHS.IncomingVal);
850 }
851};
852} // anonymous namespace
853
854namespace llvm {
855/// \brief A MemorySSAWalker that does AA walks to disambiguate accesses. It no
856/// longer does caching on its own,
857/// but the name has been retained for the moment.
858class MemorySSA::CachingWalker final : public MemorySSAWalker {
859 ClobberWalker Walker;
860 bool AutoResetWalker;
861
862 MemoryAccess *getClobberingMemoryAccess(MemoryAccess *, UpwardsMemoryQuery &);
863 void verifyRemoved(MemoryAccess *);
864
865public:
866 CachingWalker(MemorySSA *, AliasAnalysis *, DominatorTree *);
867 ~CachingWalker() override;
868
869 using MemorySSAWalker::getClobberingMemoryAccess;
870 MemoryAccess *getClobberingMemoryAccess(MemoryAccess *) override;
871 MemoryAccess *getClobberingMemoryAccess(MemoryAccess *,
872 const MemoryLocation &) override;
873 void invalidateInfo(MemoryAccess *) override;
874
875 /// Whether we call resetClobberWalker() after each time we *actually* walk to
876 /// answer a clobber query.
877 void setAutoResetWalker(bool AutoReset) { AutoResetWalker = AutoReset; }
878
879 /// Drop the walker's persistent data structures.
880 void resetClobberWalker() { Walker.reset(); }
881
882 void verify(const MemorySSA *MSSA) override {
883 MemorySSAWalker::verify(MSSA);
884 Walker.verify(MSSA);
885 }
886};
887
888void MemorySSA::renameSuccessorPhis(BasicBlock *BB, MemoryAccess *IncomingVal,
889 bool RenameAllUses) {
890 // Pass through values to our successors
891 for (const BasicBlock *S : successors(BB)) {
892 auto It = PerBlockAccesses.find(S);
893 // Rename the phi nodes in our successor block
894 if (It == PerBlockAccesses.end() || !isa<MemoryPhi>(It->second->front()))
895 continue;
896 AccessList *Accesses = It->second.get();
897 auto *Phi = cast<MemoryPhi>(&Accesses->front());
898 if (RenameAllUses) {
899 int PhiIndex = Phi->getBasicBlockIndex(BB);
900 assert(PhiIndex != -1 && "Incomplete phi during partial rename")((PhiIndex != -1 && "Incomplete phi during partial rename"
) ? static_cast<void> (0) : __assert_fail ("PhiIndex != -1 && \"Incomplete phi during partial rename\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 900, __PRETTY_FUNCTION__))
;
901 Phi->setIncomingValue(PhiIndex, IncomingVal);
902 } else
903 Phi->addIncoming(IncomingVal, BB);
904 }
905}
906
907/// \brief Rename a single basic block into MemorySSA form.
908/// Uses the standard SSA renaming algorithm.
909/// \returns The new incoming value.
910MemoryAccess *MemorySSA::renameBlock(BasicBlock *BB, MemoryAccess *IncomingVal,
911 bool RenameAllUses) {
912 auto It = PerBlockAccesses.find(BB);
913 // Skip most processing if the list is empty.
914 if (It != PerBlockAccesses.end()) {
915 AccessList *Accesses = It->second.get();
916 for (MemoryAccess &L : *Accesses) {
917 if (MemoryUseOrDef *MUD = dyn_cast<MemoryUseOrDef>(&L)) {
918 if (MUD->getDefiningAccess() == nullptr || RenameAllUses)
919 MUD->setDefiningAccess(IncomingVal);
920 if (isa<MemoryDef>(&L))
921 IncomingVal = &L;
922 } else {
923 IncomingVal = &L;
924 }
925 }
926 }
927 return IncomingVal;
928}
929
930/// \brief This is the standard SSA renaming algorithm.
931///
932/// We walk the dominator tree in preorder, renaming accesses, and then filling
933/// in phi nodes in our successors.
934void MemorySSA::renamePass(DomTreeNode *Root, MemoryAccess *IncomingVal,
935 SmallPtrSetImpl<BasicBlock *> &Visited,
936 bool SkipVisited, bool RenameAllUses) {
937 SmallVector<RenamePassData, 32> WorkStack;
938 // Skip everything if we already renamed this block and we are skipping.
939 // Note: You can't sink this into the if, because we need it to occur
940 // regardless of whether we skip blocks or not.
941 bool AlreadyVisited = !Visited.insert(Root->getBlock()).second;
942 if (SkipVisited && AlreadyVisited)
943 return;
944
945 IncomingVal = renameBlock(Root->getBlock(), IncomingVal, RenameAllUses);
946 renameSuccessorPhis(Root->getBlock(), IncomingVal, RenameAllUses);
947 WorkStack.push_back({Root, Root->begin(), IncomingVal});
948
949 while (!WorkStack.empty()) {
950 DomTreeNode *Node = WorkStack.back().DTN;
951 DomTreeNode::const_iterator ChildIt = WorkStack.back().ChildIt;
952 IncomingVal = WorkStack.back().IncomingVal;
953
954 if (ChildIt == Node->end()) {
955 WorkStack.pop_back();
956 } else {
957 DomTreeNode *Child = *ChildIt;
958 ++WorkStack.back().ChildIt;
959 BasicBlock *BB = Child->getBlock();
960 // Note: You can't sink this into the if, because we need it to occur
961 // regardless of whether we skip blocks or not.
962 AlreadyVisited = !Visited.insert(BB).second;
963 if (SkipVisited && AlreadyVisited) {
964 // We already visited this during our renaming, which can happen when
965 // being asked to rename multiple blocks. Figure out the incoming val,
966 // which is the last def.
967 // Incoming value can only change if there is a block def, and in that
968 // case, it's the last block def in the list.
969 if (auto *BlockDefs = getWritableBlockDefs(BB))
970 IncomingVal = &*BlockDefs->rbegin();
971 } else
972 IncomingVal = renameBlock(BB, IncomingVal, RenameAllUses);
973 renameSuccessorPhis(BB, IncomingVal, RenameAllUses);
974 WorkStack.push_back({Child, Child->begin(), IncomingVal});
975 }
976 }
977}
978
979/// \brief This handles unreachable block accesses by deleting phi nodes in
980/// unreachable blocks, and marking all other unreachable MemoryAccess's as
981/// being uses of the live on entry definition.
982void MemorySSA::markUnreachableAsLiveOnEntry(BasicBlock *BB) {
983 assert(!DT->isReachableFromEntry(BB) &&((!DT->isReachableFromEntry(BB) && "Reachable block found while handling unreachable blocks"
) ? static_cast<void> (0) : __assert_fail ("!DT->isReachableFromEntry(BB) && \"Reachable block found while handling unreachable blocks\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 984, __PRETTY_FUNCTION__))
984 "Reachable block found while handling unreachable blocks")((!DT->isReachableFromEntry(BB) && "Reachable block found while handling unreachable blocks"
) ? static_cast<void> (0) : __assert_fail ("!DT->isReachableFromEntry(BB) && \"Reachable block found while handling unreachable blocks\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 984, __PRETTY_FUNCTION__))
;
985
986 // Make sure phi nodes in our reachable successors end up with a
987 // LiveOnEntryDef for our incoming edge, even though our block is forward
988 // unreachable. We could just disconnect these blocks from the CFG fully,
989 // but we do not right now.
990 for (const BasicBlock *S : successors(BB)) {
991 if (!DT->isReachableFromEntry(S))
992 continue;
993 auto It = PerBlockAccesses.find(S);
994 // Rename the phi nodes in our successor block
995 if (It == PerBlockAccesses.end() || !isa<MemoryPhi>(It->second->front()))
996 continue;
997 AccessList *Accesses = It->second.get();
998 auto *Phi = cast<MemoryPhi>(&Accesses->front());
999 Phi->addIncoming(LiveOnEntryDef.get(), BB);
1000 }
1001
1002 auto It = PerBlockAccesses.find(BB);
1003 if (It == PerBlockAccesses.end())
1004 return;
1005
1006 auto &Accesses = It->second;
1007 for (auto AI = Accesses->begin(), AE = Accesses->end(); AI != AE;) {
1008 auto Next = std::next(AI);
1009 // If we have a phi, just remove it. We are going to replace all
1010 // users with live on entry.
1011 if (auto *UseOrDef = dyn_cast<MemoryUseOrDef>(AI))
1012 UseOrDef->setDefiningAccess(LiveOnEntryDef.get());
1013 else
1014 Accesses->erase(AI);
1015 AI = Next;
1016 }
1017}
1018
1019MemorySSA::MemorySSA(Function &Func, AliasAnalysis *AA, DominatorTree *DT)
1020 : AA(AA), DT(DT), F(Func), LiveOnEntryDef(nullptr), Walker(nullptr),
1021 NextID(INVALID_MEMORYACCESS_ID) {
1022 buildMemorySSA();
1023}
1024
1025MemorySSA::~MemorySSA() {
1026 // Drop all our references
1027 for (const auto &Pair : PerBlockAccesses)
1028 for (MemoryAccess &MA : *Pair.second)
1029 MA.dropAllReferences();
1030}
1031
1032MemorySSA::AccessList *MemorySSA::getOrCreateAccessList(const BasicBlock *BB) {
1033 auto Res = PerBlockAccesses.insert(std::make_pair(BB, nullptr));
1034
1035 if (Res.second)
1036 Res.first->second = make_unique<AccessList>();
1037 return Res.first->second.get();
1038}
1039MemorySSA::DefsList *MemorySSA::getOrCreateDefsList(const BasicBlock *BB) {
1040 auto Res = PerBlockDefs.insert(std::make_pair(BB, nullptr));
1041
1042 if (Res.second)
1043 Res.first->second = make_unique<DefsList>();
1044 return Res.first->second.get();
1045}
1046
1047/// This class is a batch walker of all MemoryUse's in the program, and points
1048/// their defining access at the thing that actually clobbers them. Because it
1049/// is a batch walker that touches everything, it does not operate like the
1050/// other walkers. This walker is basically performing a top-down SSA renaming
1051/// pass, where the version stack is used as the cache. This enables it to be
1052/// significantly more time and memory efficient than using the regular walker,
1053/// which is walking bottom-up.
1054class MemorySSA::OptimizeUses {
1055public:
1056 OptimizeUses(MemorySSA *MSSA, MemorySSAWalker *Walker, AliasAnalysis *AA,
1057 DominatorTree *DT)
1058 : MSSA(MSSA), Walker(Walker), AA(AA), DT(DT) {
1059 Walker = MSSA->getWalker();
1060 }
1061
1062 void optimizeUses();
1063
1064private:
1065 /// This represents where a given memorylocation is in the stack.
1066 struct MemlocStackInfo {
1067 // This essentially is keeping track of versions of the stack. Whenever
1068 // the stack changes due to pushes or pops, these versions increase.
1069 unsigned long StackEpoch;
1070 unsigned long PopEpoch;
1071 // This is the lower bound of places on the stack to check. It is equal to
1072 // the place the last stack walk ended.
1073 // Note: Correctness depends on this being initialized to 0, which densemap
1074 // does
1075 unsigned long LowerBound;
1076 const BasicBlock *LowerBoundBlock;
1077 // This is where the last walk for this memory location ended.
1078 unsigned long LastKill;
1079 bool LastKillValid;
1080 };
1081 void optimizeUsesInBlock(const BasicBlock *, unsigned long &, unsigned long &,
1082 SmallVectorImpl<MemoryAccess *> &,
1083 DenseMap<MemoryLocOrCall, MemlocStackInfo> &);
1084 MemorySSA *MSSA;
1085 MemorySSAWalker *Walker;
1086 AliasAnalysis *AA;
1087 DominatorTree *DT;
1088};
1089
1090/// Optimize the uses in a given block This is basically the SSA renaming
1091/// algorithm, with one caveat: We are able to use a single stack for all
1092/// MemoryUses. This is because the set of *possible* reaching MemoryDefs is
1093/// the same for every MemoryUse. The *actual* clobbering MemoryDef is just
1094/// going to be some position in that stack of possible ones.
1095///
1096/// We track the stack positions that each MemoryLocation needs
1097/// to check, and last ended at. This is because we only want to check the
1098/// things that changed since last time. The same MemoryLocation should
1099/// get clobbered by the same store (getModRefInfo does not use invariantness or
1100/// things like this, and if they start, we can modify MemoryLocOrCall to
1101/// include relevant data)
1102void MemorySSA::OptimizeUses::optimizeUsesInBlock(
1103 const BasicBlock *BB, unsigned long &StackEpoch, unsigned long &PopEpoch,
1104 SmallVectorImpl<MemoryAccess *> &VersionStack,
1105 DenseMap<MemoryLocOrCall, MemlocStackInfo> &LocStackInfo) {
1106
1107 /// If no accesses, nothing to do.
1108 MemorySSA::AccessList *Accesses = MSSA->getWritableBlockAccesses(BB);
1109 if (Accesses == nullptr)
1110 return;
1111
1112 // Pop everything that doesn't dominate the current block off the stack,
1113 // increment the PopEpoch to account for this.
1114 while (true) {
1115 assert(((!VersionStack.empty() && "Version stack should have liveOnEntry sentinel dominating everything"
) ? static_cast<void> (0) : __assert_fail ("!VersionStack.empty() && \"Version stack should have liveOnEntry sentinel dominating everything\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1117, __PRETTY_FUNCTION__))
1116 !VersionStack.empty() &&((!VersionStack.empty() && "Version stack should have liveOnEntry sentinel dominating everything"
) ? static_cast<void> (0) : __assert_fail ("!VersionStack.empty() && \"Version stack should have liveOnEntry sentinel dominating everything\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1117, __PRETTY_FUNCTION__))
1117 "Version stack should have liveOnEntry sentinel dominating everything")((!VersionStack.empty() && "Version stack should have liveOnEntry sentinel dominating everything"
) ? static_cast<void> (0) : __assert_fail ("!VersionStack.empty() && \"Version stack should have liveOnEntry sentinel dominating everything\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1117, __PRETTY_FUNCTION__))
;
1118 BasicBlock *BackBlock = VersionStack.back()->getBlock();
1119 if (DT->dominates(BackBlock, BB))
1120 break;
1121 while (VersionStack.back()->getBlock() == BackBlock)
1122 VersionStack.pop_back();
1123 ++PopEpoch;
1124 }
1125
1126 for (MemoryAccess &MA : *Accesses) {
1127 auto *MU = dyn_cast<MemoryUse>(&MA);
1128 if (!MU) {
1129 VersionStack.push_back(&MA);
1130 ++StackEpoch;
1131 continue;
1132 }
1133
1134 if (isUseTriviallyOptimizableToLiveOnEntry(*AA, MU->getMemoryInst())) {
1135 MU->setDefiningAccess(MSSA->getLiveOnEntryDef(), true);
1136 continue;
1137 }
1138
1139 MemoryLocOrCall UseMLOC(MU);
1140 auto &LocInfo = LocStackInfo[UseMLOC];
1141 // If the pop epoch changed, it means we've removed stuff from top of
1142 // stack due to changing blocks. We may have to reset the lower bound or
1143 // last kill info.
1144 if (LocInfo.PopEpoch != PopEpoch) {
1145 LocInfo.PopEpoch = PopEpoch;
1146 LocInfo.StackEpoch = StackEpoch;
1147 // If the lower bound was in something that no longer dominates us, we
1148 // have to reset it.
1149 // We can't simply track stack size, because the stack may have had
1150 // pushes/pops in the meantime.
1151 // XXX: This is non-optimal, but only is slower cases with heavily
1152 // branching dominator trees. To get the optimal number of queries would
1153 // be to make lowerbound and lastkill a per-loc stack, and pop it until
1154 // the top of that stack dominates us. This does not seem worth it ATM.
1155 // A much cheaper optimization would be to always explore the deepest
1156 // branch of the dominator tree first. This will guarantee this resets on
1157 // the smallest set of blocks.
1158 if (LocInfo.LowerBoundBlock && LocInfo.LowerBoundBlock != BB &&
1159 !DT->dominates(LocInfo.LowerBoundBlock, BB)) {
1160 // Reset the lower bound of things to check.
1161 // TODO: Some day we should be able to reset to last kill, rather than
1162 // 0.
1163 LocInfo.LowerBound = 0;
1164 LocInfo.LowerBoundBlock = VersionStack[0]->getBlock();
1165 LocInfo.LastKillValid = false;
1166 }
1167 } else if (LocInfo.StackEpoch != StackEpoch) {
1168 // If all that has changed is the StackEpoch, we only have to check the
1169 // new things on the stack, because we've checked everything before. In
1170 // this case, the lower bound of things to check remains the same.
1171 LocInfo.PopEpoch = PopEpoch;
1172 LocInfo.StackEpoch = StackEpoch;
1173 }
1174 if (!LocInfo.LastKillValid) {
1175 LocInfo.LastKill = VersionStack.size() - 1;
1176 LocInfo.LastKillValid = true;
1177 }
1178
1179 // At this point, we should have corrected last kill and LowerBound to be
1180 // in bounds.
1181 assert(LocInfo.LowerBound < VersionStack.size() &&((LocInfo.LowerBound < VersionStack.size() && "Lower bound out of range"
) ? static_cast<void> (0) : __assert_fail ("LocInfo.LowerBound < VersionStack.size() && \"Lower bound out of range\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1182, __PRETTY_FUNCTION__))
1182 "Lower bound out of range")((LocInfo.LowerBound < VersionStack.size() && "Lower bound out of range"
) ? static_cast<void> (0) : __assert_fail ("LocInfo.LowerBound < VersionStack.size() && \"Lower bound out of range\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1182, __PRETTY_FUNCTION__))
;
1183 assert(LocInfo.LastKill < VersionStack.size() &&((LocInfo.LastKill < VersionStack.size() && "Last kill info out of range"
) ? static_cast<void> (0) : __assert_fail ("LocInfo.LastKill < VersionStack.size() && \"Last kill info out of range\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1184, __PRETTY_FUNCTION__))
1184 "Last kill info out of range")((LocInfo.LastKill < VersionStack.size() && "Last kill info out of range"
) ? static_cast<void> (0) : __assert_fail ("LocInfo.LastKill < VersionStack.size() && \"Last kill info out of range\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1184, __PRETTY_FUNCTION__))
;
1185 // In any case, the new upper bound is the top of the stack.
1186 unsigned long UpperBound = VersionStack.size() - 1;
1187
1188 if (UpperBound - LocInfo.LowerBound > MaxCheckLimit) {
1189 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)
1190 << *(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)
1191 << " 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)
1192 << " 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)
;
1193 // Because we did not walk, LastKill is no longer valid, as this may
1194 // have been a kill.
1195 LocInfo.LastKillValid = false;
1196 continue;
1197 }
1198 bool FoundClobberResult = false;
1199 while (UpperBound > LocInfo.LowerBound) {
1200 if (isa<MemoryPhi>(VersionStack[UpperBound])) {
1201 // For phis, use the walker, see where we ended up, go there
1202 Instruction *UseInst = MU->getMemoryInst();
1203 MemoryAccess *Result = Walker->getClobberingMemoryAccess(UseInst);
1204 // We are guaranteed to find it or something is wrong
1205 while (VersionStack[UpperBound] != Result) {
1206 assert(UpperBound != 0)((UpperBound != 0) ? static_cast<void> (0) : __assert_fail
("UpperBound != 0", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1206, __PRETTY_FUNCTION__))
;
1207 --UpperBound;
1208 }
1209 FoundClobberResult = true;
1210 break;
1211 }
1212
1213 MemoryDef *MD = cast<MemoryDef>(VersionStack[UpperBound]);
1214 // If the lifetime of the pointer ends at this instruction, it's live on
1215 // entry.
1216 if (!UseMLOC.IsCall && lifetimeEndsAt(MD, UseMLOC.getLoc(), *AA)) {
1217 // Reset UpperBound to liveOnEntryDef's place in the stack
1218 UpperBound = 0;
1219 FoundClobberResult = true;
1220 break;
1221 }
1222 if (instructionClobbersQuery(MD, MU, UseMLOC, *AA)) {
1223 FoundClobberResult = true;
1224 break;
1225 }
1226 --UpperBound;
1227 }
1228 // At the end of this loop, UpperBound is either a clobber, or lower bound
1229 // PHI walking may cause it to be < LowerBound, and in fact, < LastKill.
1230 if (FoundClobberResult || UpperBound < LocInfo.LastKill) {
1231 MU->setDefiningAccess(VersionStack[UpperBound], true);
1232 // We were last killed now by where we got to
1233 LocInfo.LastKill = UpperBound;
1234 } else {
1235 // Otherwise, we checked all the new ones, and now we know we can get to
1236 // LastKill.
1237 MU->setDefiningAccess(VersionStack[LocInfo.LastKill], true);
1238 }
1239 LocInfo.LowerBound = VersionStack.size() - 1;
1240 LocInfo.LowerBoundBlock = BB;
1241 }
1242}
1243
1244/// Optimize uses to point to their actual clobbering definitions.
1245void MemorySSA::OptimizeUses::optimizeUses() {
1246 SmallVector<MemoryAccess *, 16> VersionStack;
1247 DenseMap<MemoryLocOrCall, MemlocStackInfo> LocStackInfo;
1248 VersionStack.push_back(MSSA->getLiveOnEntryDef());
1249
1250 unsigned long StackEpoch = 1;
1251 unsigned long PopEpoch = 1;
1252 // We perform a non-recursive top-down dominator tree walk.
1253 for (const auto *DomNode : depth_first(DT->getRootNode()))
1254 optimizeUsesInBlock(DomNode->getBlock(), StackEpoch, PopEpoch, VersionStack,
1255 LocStackInfo);
1256}
1257
1258void MemorySSA::placePHINodes(
1259 const SmallPtrSetImpl<BasicBlock *> &DefiningBlocks,
1260 const DenseMap<const BasicBlock *, unsigned int> &BBNumbers) {
1261 // Determine where our MemoryPhi's should go
1262 ForwardIDFCalculator IDFs(*DT);
1263 IDFs.setDefiningBlocks(DefiningBlocks);
1264 SmallVector<BasicBlock *, 32> IDFBlocks;
1265 IDFs.calculate(IDFBlocks);
1266
1267 std::sort(IDFBlocks.begin(), IDFBlocks.end(),
1268 [&BBNumbers](const BasicBlock *A, const BasicBlock *B) {
1269 return BBNumbers.lookup(A) < BBNumbers.lookup(B);
1270 });
1271
1272 // Now place MemoryPhi nodes.
1273 for (auto &BB : IDFBlocks)
1274 createMemoryPhi(BB);
1275}
1276
1277void MemorySSA::buildMemorySSA() {
1278 // We create an access to represent "live on entry", for things like
1279 // arguments or users of globals, where the memory they use is defined before
1280 // the beginning of the function. We do not actually insert it into the IR.
1281 // We do not define a live on exit for the immediate uses, and thus our
1282 // semantics do *not* imply that something with no immediate uses can simply
1283 // be removed.
1284 BasicBlock &StartingPoint = F.getEntryBlock();
1285 LiveOnEntryDef = make_unique<MemoryDef>(F.getContext(), nullptr, nullptr,
1286 &StartingPoint, NextID++);
1287 DenseMap<const BasicBlock *, unsigned int> BBNumbers;
1288 unsigned NextBBNum = 0;
1289
1290 // We maintain lists of memory accesses per-block, trading memory for time. We
1291 // could just look up the memory access for every possible instruction in the
1292 // stream.
1293 SmallPtrSet<BasicBlock *, 32> DefiningBlocks;
1294 // Go through each block, figure out where defs occur, and chain together all
1295 // the accesses.
1296 for (BasicBlock &B : F) {
1297 BBNumbers[&B] = NextBBNum++;
1298 bool InsertIntoDef = false;
1299 AccessList *Accesses = nullptr;
1300 DefsList *Defs = nullptr;
1301 for (Instruction &I : B) {
1302 MemoryUseOrDef *MUD = createNewAccess(&I);
1303 if (!MUD)
1304 continue;
1305
1306 if (!Accesses)
1307 Accesses = getOrCreateAccessList(&B);
1308 Accesses->push_back(MUD);
1309 if (isa<MemoryDef>(MUD)) {
1310 InsertIntoDef = true;
1311 if (!Defs)
1312 Defs = getOrCreateDefsList(&B);
1313 Defs->push_back(*MUD);
1314 }
1315 }
1316 if (InsertIntoDef)
1317 DefiningBlocks.insert(&B);
1318 }
1319 placePHINodes(DefiningBlocks, BBNumbers);
1320
1321 // Now do regular SSA renaming on the MemoryDef/MemoryUse. Visited will get
1322 // filled in with all blocks.
1323 SmallPtrSet<BasicBlock *, 16> Visited;
1324 renamePass(DT->getRootNode(), LiveOnEntryDef.get(), Visited);
1325
1326 CachingWalker *Walker = getWalkerImpl();
1327
1328 // We're doing a batch of updates; don't drop useful caches between them.
1329 Walker->setAutoResetWalker(false);
1330 OptimizeUses(this, Walker, AA, DT).optimizeUses();
1331 Walker->setAutoResetWalker(true);
1332 Walker->resetClobberWalker();
1333
1334 // Mark the uses in unreachable blocks as live on entry, so that they go
1335 // somewhere.
1336 for (auto &BB : F)
1337 if (!Visited.count(&BB))
1338 markUnreachableAsLiveOnEntry(&BB);
1339}
1340
1341MemorySSAWalker *MemorySSA::getWalker() { return getWalkerImpl(); }
1342
1343MemorySSA::CachingWalker *MemorySSA::getWalkerImpl() {
1344 if (Walker)
1345 return Walker.get();
1346
1347 Walker = make_unique<CachingWalker>(this, AA, DT);
1348 return Walker.get();
1349}
1350
1351// This is a helper function used by the creation routines. It places NewAccess
1352// into the access and defs lists for a given basic block, at the given
1353// insertion point.
1354void MemorySSA::insertIntoListsForBlock(MemoryAccess *NewAccess,
1355 const BasicBlock *BB,
1356 InsertionPlace Point) {
1357 auto *Accesses = getOrCreateAccessList(BB);
1358 if (Point == Beginning) {
1359 // If it's a phi node, it goes first, otherwise, it goes after any phi
1360 // nodes.
1361 if (isa<MemoryPhi>(NewAccess)) {
1362 Accesses->push_front(NewAccess);
1363 auto *Defs = getOrCreateDefsList(BB);
1364 Defs->push_front(*NewAccess);
1365 } else {
1366 auto AI = find_if_not(
1367 *Accesses, [](const MemoryAccess &MA) { return isa<MemoryPhi>(MA); });
1368 Accesses->insert(AI, NewAccess);
1369 if (!isa<MemoryUse>(NewAccess)) {
1370 auto *Defs = getOrCreateDefsList(BB);
1371 auto DI = find_if_not(
1372 *Defs, [](const MemoryAccess &MA) { return isa<MemoryPhi>(MA); });
1373 Defs->insert(DI, *NewAccess);
1374 }
1375 }
1376 } else {
1377 Accesses->push_back(NewAccess);
1378 if (!isa<MemoryUse>(NewAccess)) {
1379 auto *Defs = getOrCreateDefsList(BB);
1380 Defs->push_back(*NewAccess);
1381 }
1382 }
1383 BlockNumberingValid.erase(BB);
1384}
1385
1386void MemorySSA::insertIntoListsBefore(MemoryAccess *What, const BasicBlock *BB,
1387 AccessList::iterator InsertPt) {
1388 auto *Accesses = getWritableBlockAccesses(BB);
1389 bool WasEnd = InsertPt == Accesses->end();
1390 Accesses->insert(AccessList::iterator(InsertPt), What);
1391 if (!isa<MemoryUse>(What)) {
1392 auto *Defs = getOrCreateDefsList(BB);
1393 // If we got asked to insert at the end, we have an easy job, just shove it
1394 // at the end. If we got asked to insert before an existing def, we also get
1395 // an terator. If we got asked to insert before a use, we have to hunt for
1396 // the next def.
1397 if (WasEnd) {
1398 Defs->push_back(*What);
1399 } else if (isa<MemoryDef>(InsertPt)) {
1400 Defs->insert(InsertPt->getDefsIterator(), *What);
1401 } else {
1402 while (InsertPt != Accesses->end() && !isa<MemoryDef>(InsertPt))
1403 ++InsertPt;
1404 // Either we found a def, or we are inserting at the end
1405 if (InsertPt == Accesses->end())
1406 Defs->push_back(*What);
1407 else
1408 Defs->insert(InsertPt->getDefsIterator(), *What);
1409 }
1410 }
1411 BlockNumberingValid.erase(BB);
1412}
1413
1414// Move What before Where in the IR. The end result is taht What will belong to
1415// the right lists and have the right Block set, but will not otherwise be
1416// correct. It will not have the right defining access, and if it is a def,
1417// things below it will not properly be updated.
1418void MemorySSA::moveTo(MemoryUseOrDef *What, BasicBlock *BB,
1419 AccessList::iterator Where) {
1420 // Keep it in the lookup tables, remove from the lists
1421 removeFromLists(What, false);
1422 What->setBlock(BB);
1423 insertIntoListsBefore(What, BB, Where);
1424}
1425
1426void MemorySSA::moveTo(MemoryUseOrDef *What, BasicBlock *BB,
1427 InsertionPlace Point) {
1428 removeFromLists(What, false);
1429 What->setBlock(BB);
1430 insertIntoListsForBlock(What, BB, Point);
1431}
1432
1433MemoryPhi *MemorySSA::createMemoryPhi(BasicBlock *BB) {
1434 assert(!getMemoryAccess(BB) && "MemoryPhi already exists for this BB")((!getMemoryAccess(BB) && "MemoryPhi already exists for this BB"
) ? static_cast<void> (0) : __assert_fail ("!getMemoryAccess(BB) && \"MemoryPhi already exists for this BB\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1434, __PRETTY_FUNCTION__))
;
1435 MemoryPhi *Phi = new MemoryPhi(BB->getContext(), BB, NextID++);
1436 // Phi's always are placed at the front of the block.
1437 insertIntoListsForBlock(Phi, BB, Beginning);
1438 ValueToMemoryAccess[BB] = Phi;
1439 return Phi;
1440}
1441
1442MemoryUseOrDef *MemorySSA::createDefinedAccess(Instruction *I,
1443 MemoryAccess *Definition) {
1444 assert(!isa<PHINode>(I) && "Cannot create a defined access for a PHI")((!isa<PHINode>(I) && "Cannot create a defined access for a PHI"
) ? static_cast<void> (0) : __assert_fail ("!isa<PHINode>(I) && \"Cannot create a defined access for a PHI\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1444, __PRETTY_FUNCTION__))
;
1445 MemoryUseOrDef *NewAccess = createNewAccess(I);
1446 assert(((NewAccess != nullptr && "Tried to create a memory access for a non-memory touching instruction"
) ? static_cast<void> (0) : __assert_fail ("NewAccess != nullptr && \"Tried to create a memory access for a non-memory touching instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1448, __PRETTY_FUNCTION__))
1447 NewAccess != nullptr &&((NewAccess != nullptr && "Tried to create a memory access for a non-memory touching instruction"
) ? static_cast<void> (0) : __assert_fail ("NewAccess != nullptr && \"Tried to create a memory access for a non-memory touching instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1448, __PRETTY_FUNCTION__))
1448 "Tried to create a memory access for a non-memory touching instruction")((NewAccess != nullptr && "Tried to create a memory access for a non-memory touching instruction"
) ? static_cast<void> (0) : __assert_fail ("NewAccess != nullptr && \"Tried to create a memory access for a non-memory touching instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1448, __PRETTY_FUNCTION__))
;
1449 NewAccess->setDefiningAccess(Definition);
1450 return NewAccess;
1451}
1452
1453// Return true if the instruction has ordering constraints.
1454// Note specifically that this only considers stores and loads
1455// because others are still considered ModRef by getModRefInfo.
1456static inline bool isOrdered(const Instruction *I) {
1457 if (auto *SI = dyn_cast<StoreInst>(I)) {
1458 if (!SI->isUnordered())
1459 return true;
1460 } else if (auto *LI = dyn_cast<LoadInst>(I)) {
1461 if (!LI->isUnordered())
1462 return true;
1463 }
1464 return false;
1465}
1466/// \brief Helper function to create new memory accesses
1467MemoryUseOrDef *MemorySSA::createNewAccess(Instruction *I) {
1468 // The assume intrinsic has a control dependency which we model by claiming
1469 // that it writes arbitrarily. Ignore that fake memory dependency here.
1470 // FIXME: Replace this special casing with a more accurate modelling of
1471 // assume's control dependency.
1472 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I))
1473 if (II->getIntrinsicID() == Intrinsic::assume)
1474 return nullptr;
1475
1476 // Find out what affect this instruction has on memory.
1477 ModRefInfo ModRef = AA->getModRefInfo(I);
1478 // The isOrdered check is used to ensure that volatiles end up as defs
1479 // (atomics end up as ModRef right now anyway). Until we separate the
1480 // ordering chain from the memory chain, this enables people to see at least
1481 // some relative ordering to volatiles. Note that getClobberingMemoryAccess
1482 // will still give an answer that bypasses other volatile loads. TODO:
1483 // Separate memory aliasing and ordering into two different chains so that we
1484 // can precisely represent both "what memory will this read/write/is clobbered
1485 // by" and "what instructions can I move this past".
1486 bool Def = bool(ModRef & MRI_Mod) || isOrdered(I);
1487 bool Use = bool(ModRef & MRI_Ref);
1488
1489 // It's possible for an instruction to not modify memory at all. During
1490 // construction, we ignore them.
1491 if (!Def && !Use)
1492 return nullptr;
1493
1494 assert((Def || Use) &&(((Def || Use) && "Trying to create a memory access with a non-memory instruction"
) ? static_cast<void> (0) : __assert_fail ("(Def || Use) && \"Trying to create a memory access with a non-memory instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1495, __PRETTY_FUNCTION__))
1495 "Trying to create a memory access with a non-memory instruction")(((Def || Use) && "Trying to create a memory access with a non-memory instruction"
) ? static_cast<void> (0) : __assert_fail ("(Def || Use) && \"Trying to create a memory access with a non-memory instruction\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1495, __PRETTY_FUNCTION__))
;
1496
1497 MemoryUseOrDef *MUD;
1498 if (Def)
1499 MUD = new MemoryDef(I->getContext(), nullptr, I, I->getParent(), NextID++);
1500 else
1501 MUD = new MemoryUse(I->getContext(), nullptr, I, I->getParent());
1502 ValueToMemoryAccess[I] = MUD;
1503 return MUD;
1504}
1505
1506/// \brief Returns true if \p Replacer dominates \p Replacee .
1507bool MemorySSA::dominatesUse(const MemoryAccess *Replacer,
1508 const MemoryAccess *Replacee) const {
1509 if (isa<MemoryUseOrDef>(Replacee))
1510 return DT->dominates(Replacer->getBlock(), Replacee->getBlock());
1511 const auto *MP = cast<MemoryPhi>(Replacee);
1512 // For a phi node, the use occurs in the predecessor block of the phi node.
1513 // Since we may occur multiple times in the phi node, we have to check each
1514 // operand to ensure Replacer dominates each operand where Replacee occurs.
1515 for (const Use &Arg : MP->operands()) {
1516 if (Arg.get() != Replacee &&
1517 !DT->dominates(Replacer->getBlock(), MP->getIncomingBlock(Arg)))
1518 return false;
1519 }
1520 return true;
1521}
1522
1523/// \brief Properly remove \p MA from all of MemorySSA's lookup tables.
1524void MemorySSA::removeFromLookups(MemoryAccess *MA) {
1525 assert(MA->use_empty() &&((MA->use_empty() && "Trying to remove memory access that still has uses"
) ? static_cast<void> (0) : __assert_fail ("MA->use_empty() && \"Trying to remove memory access that still has uses\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1526, __PRETTY_FUNCTION__))
1526 "Trying to remove memory access that still has uses")((MA->use_empty() && "Trying to remove memory access that still has uses"
) ? static_cast<void> (0) : __assert_fail ("MA->use_empty() && \"Trying to remove memory access that still has uses\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1526, __PRETTY_FUNCTION__))
;
1527 BlockNumbering.erase(MA);
1528 if (MemoryUseOrDef *MUD = dyn_cast<MemoryUseOrDef>(MA))
1529 MUD->setDefiningAccess(nullptr);
1530 // Invalidate our walker's cache if necessary
1531 if (!isa<MemoryUse>(MA))
1532 Walker->invalidateInfo(MA);
1533 // The call below to erase will destroy MA, so we can't change the order we
1534 // are doing things here
1535 Value *MemoryInst;
1536 if (MemoryUseOrDef *MUD = dyn_cast<MemoryUseOrDef>(MA)) {
1537 MemoryInst = MUD->getMemoryInst();
1538 } else {
1539 MemoryInst = MA->getBlock();
1540 }
1541 auto VMA = ValueToMemoryAccess.find(MemoryInst);
1542 if (VMA->second == MA)
1543 ValueToMemoryAccess.erase(VMA);
1544}
1545
1546/// \brief Properly remove \p MA from all of MemorySSA's lists.
1547///
1548/// Because of the way the intrusive list and use lists work, it is important to
1549/// do removal in the right order.
1550/// ShouldDelete defaults to true, and will cause the memory access to also be
1551/// deleted, not just removed.
1552void MemorySSA::removeFromLists(MemoryAccess *MA, bool ShouldDelete) {
1553 // The access list owns the reference, so we erase it from the non-owning list
1554 // first.
1555 if (!isa<MemoryUse>(MA)) {
1556 auto DefsIt = PerBlockDefs.find(MA->getBlock());
1557 std::unique_ptr<DefsList> &Defs = DefsIt->second;
1558 Defs->remove(*MA);
1559 if (Defs->empty())
1560 PerBlockDefs.erase(DefsIt);
1561 }
1562
1563 // The erase call here will delete it. If we don't want it deleted, we call
1564 // remove instead.
1565 auto AccessIt = PerBlockAccesses.find(MA->getBlock());
1566 std::unique_ptr<AccessList> &Accesses = AccessIt->second;
1567 if (ShouldDelete)
1568 Accesses->erase(MA);
1569 else
1570 Accesses->remove(MA);
1571
1572 if (Accesses->empty())
1573 PerBlockAccesses.erase(AccessIt);
1574}
1575
1576void MemorySSA::print(raw_ostream &OS) const {
1577 MemorySSAAnnotatedWriter Writer(this);
1578 F.print(OS, &Writer);
1579}
1580
1581#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1582LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void MemorySSA::dump() const { print(dbgs()); }
1583#endif
1584
1585void MemorySSA::verifyMemorySSA() const {
1586 verifyDefUses(F);
1587 verifyDomination(F);
1588 verifyOrdering(F);
1589 Walker->verify(this);
1590}
1591
1592/// \brief Verify that the order and existence of MemoryAccesses matches the
1593/// order and existence of memory affecting instructions.
1594void MemorySSA::verifyOrdering(Function &F) const {
1595 // Walk all the blocks, comparing what the lookups think and what the access
1596 // lists think, as well as the order in the blocks vs the order in the access
1597 // lists.
1598 SmallVector<MemoryAccess *, 32> ActualAccesses;
1599 SmallVector<MemoryAccess *, 32> ActualDefs;
1600 for (BasicBlock &B : F) {
1601 const AccessList *AL = getBlockAccesses(&B);
1602 const auto *DL = getBlockDefs(&B);
1603 MemoryAccess *Phi = getMemoryAccess(&B);
1604 if (Phi) {
1605 ActualAccesses.push_back(Phi);
1606 ActualDefs.push_back(Phi);
1607 }
1608
1609 for (Instruction &I : B) {
1610 MemoryAccess *MA = getMemoryAccess(&I);
1611 assert((!MA || (AL && (isa<MemoryUse>(MA) || DL))) &&(((!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") ? static_cast<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\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1614, __PRETTY_FUNCTION__))
1612 "We have memory affecting instructions "(((!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") ? static_cast<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\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1614, __PRETTY_FUNCTION__))
1613 "in this block but they are not in the "(((!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") ? static_cast<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\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1614, __PRETTY_FUNCTION__))
1614 "access list or defs list")(((!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") ? static_cast<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\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1614, __PRETTY_FUNCTION__))
;
1615 if (MA) {
1616 ActualAccesses.push_back(MA);
1617 if (isa<MemoryDef>(MA))
1618 ActualDefs.push_back(MA);
1619 }
1620 }
1621 // Either we hit the assert, really have no accesses, or we have both
1622 // accesses and an access list.
1623 // Same with defs.
1624 if (!AL && !DL)
1625 continue;
1626 assert(AL->size() == ActualAccesses.size() &&((AL->size() == ActualAccesses.size() && "We don't have the same number of accesses in the block as on the "
"access list") ? static_cast<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\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1628, __PRETTY_FUNCTION__))
1627 "We don't have the same number of accesses in the block as on the "((AL->size() == ActualAccesses.size() && "We don't have the same number of accesses in the block as on the "
"access list") ? static_cast<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\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1628, __PRETTY_FUNCTION__))
1628 "access list")((AL->size() == ActualAccesses.size() && "We don't have the same number of accesses in the block as on the "
"access list") ? static_cast<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\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1628, __PRETTY_FUNCTION__))
;
1629 assert((DL || ActualDefs.size() == 0) &&(((DL || ActualDefs.size() == 0) && "Either we should have a defs list, or we should have no defs"
) ? static_cast<void> (0) : __assert_fail ("(DL || ActualDefs.size() == 0) && \"Either we should have a defs list, or we should have no defs\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1630, __PRETTY_FUNCTION__))
1630 "Either we should have a defs list, or we should have no defs")(((DL || ActualDefs.size() == 0) && "Either we should have a defs list, or we should have no defs"
) ? static_cast<void> (0) : __assert_fail ("(DL || ActualDefs.size() == 0) && \"Either we should have a defs list, or we should have no defs\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1630, __PRETTY_FUNCTION__))
;
1631 assert((!DL || DL->size() == ActualDefs.size()) &&(((!DL || DL->size() == ActualDefs.size()) && "We don't have the same number of defs in the block as on the "
"def list") ? static_cast<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\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1633, __PRETTY_FUNCTION__))
1632 "We don't have the same number of defs in the block as on the "(((!DL || DL->size() == ActualDefs.size()) && "We don't have the same number of defs in the block as on the "
"def list") ? static_cast<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\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1633, __PRETTY_FUNCTION__))
1633 "def list")(((!DL || DL->size() == ActualDefs.size()) && "We don't have the same number of defs in the block as on the "
"def list") ? static_cast<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\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1633, __PRETTY_FUNCTION__))
;
1634 auto ALI = AL->begin();
1635 auto AAI = ActualAccesses.begin();
1636 while (ALI != AL->end() && AAI != ActualAccesses.end()) {
1637 assert(&*ALI == *AAI && "Not the same accesses in the same order")((&*ALI == *AAI && "Not the same accesses in the same order"
) ? static_cast<void> (0) : __assert_fail ("&*ALI == *AAI && \"Not the same accesses in the same order\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1637, __PRETTY_FUNCTION__))
;
1638 ++ALI;
1639 ++AAI;
1640 }
1641 ActualAccesses.clear();
1642 if (DL) {
1643 auto DLI = DL->begin();
1644 auto ADI = ActualDefs.begin();
1645 while (DLI != DL->end() && ADI != ActualDefs.end()) {
1646 assert(&*DLI == *ADI && "Not the same defs in the same order")((&*DLI == *ADI && "Not the same defs in the same order"
) ? static_cast<void> (0) : __assert_fail ("&*DLI == *ADI && \"Not the same defs in the same order\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1646, __PRETTY_FUNCTION__))
;
1647 ++DLI;
1648 ++ADI;
1649 }
1650 }
1651 ActualDefs.clear();
1652 }
1653}
1654
1655/// \brief Verify the domination properties of MemorySSA by checking that each
1656/// definition dominates all of its uses.
1657void MemorySSA::verifyDomination(Function &F) const {
1658#ifndef NDEBUG
1659 for (BasicBlock &B : F) {
1660 // Phi nodes are attached to basic blocks
1661 if (MemoryPhi *MP = getMemoryAccess(&B))
1662 for (const Use &U : MP->uses())
1663 assert(dominates(MP, U) && "Memory PHI does not dominate it's uses")((dominates(MP, U) && "Memory PHI does not dominate it's uses"
) ? static_cast<void> (0) : __assert_fail ("dominates(MP, U) && \"Memory PHI does not dominate it's uses\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1663, __PRETTY_FUNCTION__))
;
1664
1665 for (Instruction &I : B) {
1666 MemoryAccess *MD = dyn_cast_or_null<MemoryDef>(getMemoryAccess(&I));
1667 if (!MD)
1668 continue;
1669
1670 for (const Use &U : MD->uses())
1671 assert(dominates(MD, U) && "Memory Def does not dominate it's uses")((dominates(MD, U) && "Memory Def does not dominate it's uses"
) ? static_cast<void> (0) : __assert_fail ("dominates(MD, U) && \"Memory Def does not dominate it's uses\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1671, __PRETTY_FUNCTION__))
;
1672 }
1673 }
1674#endif
1675}
1676
1677/// \brief Verify the def-use lists in MemorySSA, by verifying that \p Use
1678/// appears in the use list of \p Def.
1679
1680void MemorySSA::verifyUseInDefs(MemoryAccess *Def, MemoryAccess *Use) const {
1681#ifndef NDEBUG
1682 // The live on entry use may cause us to get a NULL def here
1683 if (!Def)
1684 assert(isLiveOnEntryDef(Use) &&((isLiveOnEntryDef(Use) && "Null def but use not point to live on entry def"
) ? static_cast<void> (0) : __assert_fail ("isLiveOnEntryDef(Use) && \"Null def but use not point to live on entry def\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1685, __PRETTY_FUNCTION__))
1685 "Null def but use not point to live on entry def")((isLiveOnEntryDef(Use) && "Null def but use not point to live on entry def"
) ? static_cast<void> (0) : __assert_fail ("isLiveOnEntryDef(Use) && \"Null def but use not point to live on entry def\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1685, __PRETTY_FUNCTION__))
;
1686 else
1687 assert(is_contained(Def->users(), Use) &&((is_contained(Def->users(), Use) && "Did not find use in def's use list"
) ? static_cast<void> (0) : __assert_fail ("is_contained(Def->users(), Use) && \"Did not find use in def's use list\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1688, __PRETTY_FUNCTION__))
1688 "Did not find use in def's use list")((is_contained(Def->users(), Use) && "Did not find use in def's use list"
) ? static_cast<void> (0) : __assert_fail ("is_contained(Def->users(), Use) && \"Did not find use in def's use list\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1688, __PRETTY_FUNCTION__))
;
1689#endif
1690}
1691
1692/// \brief Verify the immediate use information, by walking all the memory
1693/// accesses and verifying that, for each use, it appears in the
1694/// appropriate def's use list
1695void MemorySSA::verifyDefUses(Function &F) const {
1696 for (BasicBlock &B : F) {
1697 // Phi nodes are attached to basic blocks
1698 if (MemoryPhi *Phi = getMemoryAccess(&B)) {
1699 assert(Phi->getNumOperands() == static_cast<unsigned>(std::distance(((Phi->getNumOperands() == static_cast<unsigned>(std
::distance( pred_begin(&B), pred_end(&B))) &&
"Incomplete MemoryPhi Node") ? static_cast<void> (0) :
__assert_fail ("Phi->getNumOperands() == static_cast<unsigned>(std::distance( pred_begin(&B), pred_end(&B))) && \"Incomplete MemoryPhi Node\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1701, __PRETTY_FUNCTION__))
1700 pred_begin(&B), pred_end(&B))) &&((Phi->getNumOperands() == static_cast<unsigned>(std
::distance( pred_begin(&B), pred_end(&B))) &&
"Incomplete MemoryPhi Node") ? static_cast<void> (0) :
__assert_fail ("Phi->getNumOperands() == static_cast<unsigned>(std::distance( pred_begin(&B), pred_end(&B))) && \"Incomplete MemoryPhi Node\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1701, __PRETTY_FUNCTION__))
1701 "Incomplete MemoryPhi Node")((Phi->getNumOperands() == static_cast<unsigned>(std
::distance( pred_begin(&B), pred_end(&B))) &&
"Incomplete MemoryPhi Node") ? static_cast<void> (0) :
__assert_fail ("Phi->getNumOperands() == static_cast<unsigned>(std::distance( pred_begin(&B), pred_end(&B))) && \"Incomplete MemoryPhi Node\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1701, __PRETTY_FUNCTION__))
;
1702 for (unsigned I = 0, E = Phi->getNumIncomingValues(); I != E; ++I)
1703 verifyUseInDefs(Phi->getIncomingValue(I), Phi);
1704 }
1705
1706 for (Instruction &I : B) {
1707 if (MemoryUseOrDef *MA = getMemoryAccess(&I)) {
1708 verifyUseInDefs(MA->getDefiningAccess(), MA);
1709 }
1710 }
1711 }
1712}
1713
1714MemoryUseOrDef *MemorySSA::getMemoryAccess(const Instruction *I) const {
1715 return cast_or_null<MemoryUseOrDef>(ValueToMemoryAccess.lookup(I));
1716}
1717
1718MemoryPhi *MemorySSA::getMemoryAccess(const BasicBlock *BB) const {
1719 return cast_or_null<MemoryPhi>(ValueToMemoryAccess.lookup(cast<Value>(BB)));
1720}
1721
1722/// Perform a local numbering on blocks so that instruction ordering can be
1723/// determined in constant time.
1724/// TODO: We currently just number in order. If we numbered by N, we could
1725/// allow at least N-1 sequences of insertBefore or insertAfter (and at least
1726/// log2(N) sequences of mixed before and after) without needing to invalidate
1727/// the numbering.
1728void MemorySSA::renumberBlock(const BasicBlock *B) const {
1729 // The pre-increment ensures the numbers really start at 1.
1730 unsigned long CurrentNumber = 0;
1731 const AccessList *AL = getBlockAccesses(B);
1732 assert(AL != nullptr && "Asking to renumber an empty block")((AL != nullptr && "Asking to renumber an empty block"
) ? static_cast<void> (0) : __assert_fail ("AL != nullptr && \"Asking to renumber an empty block\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1732, __PRETTY_FUNCTION__))
;
1733 for (const auto &I : *AL)
1734 BlockNumbering[&I] = ++CurrentNumber;
1735 BlockNumberingValid.insert(B);
1736}
1737
1738/// \brief Determine, for two memory accesses in the same block,
1739/// whether \p Dominator dominates \p Dominatee.
1740/// \returns True if \p Dominator dominates \p Dominatee.
1741bool MemorySSA::locallyDominates(const MemoryAccess *Dominator,
1742 const MemoryAccess *Dominatee) const {
1743
1744 const BasicBlock *DominatorBlock = Dominator->getBlock();
1745
1746 assert((DominatorBlock == Dominatee->getBlock()) &&(((DominatorBlock == Dominatee->getBlock()) && "Asking for local domination when accesses are in different blocks!"
) ? static_cast<void> (0) : __assert_fail ("(DominatorBlock == Dominatee->getBlock()) && \"Asking for local domination when accesses are in different blocks!\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1747, __PRETTY_FUNCTION__))
1747 "Asking for local domination when accesses are in different blocks!")(((DominatorBlock == Dominatee->getBlock()) && "Asking for local domination when accesses are in different blocks!"
) ? static_cast<void> (0) : __assert_fail ("(DominatorBlock == Dominatee->getBlock()) && \"Asking for local domination when accesses are in different blocks!\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1747, __PRETTY_FUNCTION__))
;
1748 // A node dominates itself.
1749 if (Dominatee == Dominator)
1750 return true;
1751
1752 // When Dominatee is defined on function entry, it is not dominated by another
1753 // memory access.
1754 if (isLiveOnEntryDef(Dominatee))
1755 return false;
1756
1757 // When Dominator is defined on function entry, it dominates the other memory
1758 // access.
1759 if (isLiveOnEntryDef(Dominator))
1760 return true;
1761
1762 if (!BlockNumberingValid.count(DominatorBlock))
1763 renumberBlock(DominatorBlock);
1764
1765 unsigned long DominatorNum = BlockNumbering.lookup(Dominator);
1766 // All numbers start with 1
1767 assert(DominatorNum != 0 && "Block was not numbered properly")((DominatorNum != 0 && "Block was not numbered properly"
) ? static_cast<void> (0) : __assert_fail ("DominatorNum != 0 && \"Block was not numbered properly\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1767, __PRETTY_FUNCTION__))
;
1768 unsigned long DominateeNum = BlockNumbering.lookup(Dominatee);
1769 assert(DominateeNum != 0 && "Block was not numbered properly")((DominateeNum != 0 && "Block was not numbered properly"
) ? static_cast<void> (0) : __assert_fail ("DominateeNum != 0 && \"Block was not numbered properly\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1769, __PRETTY_FUNCTION__))
;
1770 return DominatorNum < DominateeNum;
1771}
1772
1773bool MemorySSA::dominates(const MemoryAccess *Dominator,
1774 const MemoryAccess *Dominatee) const {
1775 if (Dominator == Dominatee)
1776 return true;
1777
1778 if (isLiveOnEntryDef(Dominatee))
1779 return false;
1780
1781 if (Dominator->getBlock() != Dominatee->getBlock())
1782 return DT->dominates(Dominator->getBlock(), Dominatee->getBlock());
1783 return locallyDominates(Dominator, Dominatee);
1784}
1785
1786bool MemorySSA::dominates(const MemoryAccess *Dominator,
1787 const Use &Dominatee) const {
1788 if (MemoryPhi *MP = dyn_cast<MemoryPhi>(Dominatee.getUser())) {
1789 BasicBlock *UseBB = MP->getIncomingBlock(Dominatee);
1790 // The def must dominate the incoming block of the phi.
1791 if (UseBB != Dominator->getBlock())
1792 return DT->dominates(Dominator->getBlock(), UseBB);
1793 // If the UseBB and the DefBB are the same, compare locally.
1794 return locallyDominates(Dominator, cast<MemoryAccess>(Dominatee));
1795 }
1796 // If it's not a PHI node use, the normal dominates can already handle it.
1797 return dominates(Dominator, cast<MemoryAccess>(Dominatee.getUser()));
1798}
1799
1800const static char LiveOnEntryStr[] = "liveOnEntry";
1801
1802void MemoryAccess::print(raw_ostream &OS) const {
1803 switch (getValueID()) {
1804 case MemoryPhiVal: return static_cast<const MemoryPhi *>(this)->print(OS);
1805 case MemoryDefVal: return static_cast<const MemoryDef *>(this)->print(OS);
1806 case MemoryUseVal: return static_cast<const MemoryUse *>(this)->print(OS);
1807 }
1808 llvm_unreachable("invalid value id")::llvm::llvm_unreachable_internal("invalid value id", "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1808)
;
1809}
1810
1811void MemoryDef::print(raw_ostream &OS) const {
1812 MemoryAccess *UO = getDefiningAccess();
1813
1814 OS << getID() << " = MemoryDef(";
1815 if (UO && UO->getID())
1816 OS << UO->getID();
1817 else
1818 OS << LiveOnEntryStr;
1819 OS << ')';
1820}
1821
1822void MemoryPhi::print(raw_ostream &OS) const {
1823 bool First = true;
1824 OS << getID() << " = MemoryPhi(";
1825 for (const auto &Op : operands()) {
1826 BasicBlock *BB = getIncomingBlock(Op);
1827 MemoryAccess *MA = cast<MemoryAccess>(Op);
1828 if (!First)
1829 OS << ',';
1830 else
1831 First = false;
1832
1833 OS << '{';
1834 if (BB->hasName())
1835 OS << BB->getName();
1836 else
1837 BB->printAsOperand(OS, false);
1838 OS << ',';
1839 if (unsigned ID = MA->getID())
1840 OS << ID;
1841 else
1842 OS << LiveOnEntryStr;
1843 OS << '}';
1844 }
1845 OS << ')';
1846}
1847
1848void MemoryUse::print(raw_ostream &OS) const {
1849 MemoryAccess *UO = getDefiningAccess();
1850 OS << "MemoryUse(";
1851 if (UO && UO->getID())
1852 OS << UO->getID();
1853 else
1854 OS << LiveOnEntryStr;
1855 OS << ')';
1856}
1857
1858void MemoryAccess::dump() const {
1859// Cannot completely remove virtual function even in release mode.
1860#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1861 print(dbgs());
1862 dbgs() << "\n";
1863#endif
1864}
1865
1866char MemorySSAPrinterLegacyPass::ID = 0;
1867
1868MemorySSAPrinterLegacyPass::MemorySSAPrinterLegacyPass() : FunctionPass(ID) {
1869 initializeMemorySSAPrinterLegacyPassPass(*PassRegistry::getPassRegistry());
1870}
1871
1872void MemorySSAPrinterLegacyPass::getAnalysisUsage(AnalysisUsage &AU) const {
1873 AU.setPreservesAll();
1874 AU.addRequired<MemorySSAWrapperPass>();
1875 AU.addPreserved<MemorySSAWrapperPass>();
1876}
1877
1878bool MemorySSAPrinterLegacyPass::runOnFunction(Function &F) {
1879 auto &MSSA = getAnalysis<MemorySSAWrapperPass>().getMSSA();
1880 MSSA.print(dbgs());
1881 if (VerifyMemorySSA)
1882 MSSA.verifyMemorySSA();
1883 return false;
1884}
1885
1886AnalysisKey MemorySSAAnalysis::Key;
1887
1888MemorySSAAnalysis::Result MemorySSAAnalysis::run(Function &F,
1889 FunctionAnalysisManager &AM) {
1890 auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
1891 auto &AA = AM.getResult<AAManager>(F);
1892 return MemorySSAAnalysis::Result(make_unique<MemorySSA>(F, &AA, &DT));
1893}
1894
1895PreservedAnalyses MemorySSAPrinterPass::run(Function &F,
1896 FunctionAnalysisManager &AM) {
1897 OS << "MemorySSA for function: " << F.getName() << "\n";
1898 AM.getResult<MemorySSAAnalysis>(F).getMSSA().print(OS);
1899
1900 return PreservedAnalyses::all();
1901}
1902
1903PreservedAnalyses MemorySSAVerifierPass::run(Function &F,
1904 FunctionAnalysisManager &AM) {
1905 AM.getResult<MemorySSAAnalysis>(F).getMSSA().verifyMemorySSA();
1906
1907 return PreservedAnalyses::all();
1908}
1909
1910char MemorySSAWrapperPass::ID = 0;
1911
1912MemorySSAWrapperPass::MemorySSAWrapperPass() : FunctionPass(ID) {
1913 initializeMemorySSAWrapperPassPass(*PassRegistry::getPassRegistry());
1914}
1915
1916void MemorySSAWrapperPass::releaseMemory() { MSSA.reset(); }
1917
1918void MemorySSAWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
1919 AU.setPreservesAll();
1920 AU.addRequiredTransitive<DominatorTreeWrapperPass>();
1921 AU.addRequiredTransitive<AAResultsWrapperPass>();
1922}
1923
1924bool MemorySSAWrapperPass::runOnFunction(Function &F) {
1925 auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
1926 auto &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
1927 MSSA.reset(new MemorySSA(F, &AA, &DT));
1928 return false;
1929}
1930
1931void MemorySSAWrapperPass::verifyAnalysis() const { MSSA->verifyMemorySSA(); }
1932
1933void MemorySSAWrapperPass::print(raw_ostream &OS, const Module *M) const {
1934 MSSA->print(OS);
1935}
1936
1937MemorySSAWalker::MemorySSAWalker(MemorySSA *M) : MSSA(M) {}
1938
1939MemorySSA::CachingWalker::CachingWalker(MemorySSA *M, AliasAnalysis *A,
1940 DominatorTree *D)
1941 : MemorySSAWalker(M), Walker(*M, *A, *D), AutoResetWalker(true) {}
1942
1943MemorySSA::CachingWalker::~CachingWalker() {}
1944
1945void MemorySSA::CachingWalker::invalidateInfo(MemoryAccess *MA) {
1946 if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA))
1947 MUD->resetOptimized();
1948}
1949
1950/// \brief Walk the use-def chains starting at \p MA and find
1951/// the MemoryAccess that actually clobbers Loc.
1952///
1953/// \returns our clobbering memory access
1954MemoryAccess *MemorySSA::CachingWalker::getClobberingMemoryAccess(
1955 MemoryAccess *StartingAccess, UpwardsMemoryQuery &Q) {
1956 MemoryAccess *New = Walker.findClobber(StartingAccess, Q);
1957#ifdef EXPENSIVE_CHECKS
1958 MemoryAccess *NewNoCache = Walker.findClobber(StartingAccess, Q);
1959 assert(NewNoCache == New && "Cache made us hand back a different result?")((NewNoCache == New && "Cache made us hand back a different result?"
) ? static_cast<void> (0) : __assert_fail ("NewNoCache == New && \"Cache made us hand back a different result?\""
, "/tmp/buildd/llvm-toolchain-snapshot-5.0~svn303373/lib/Analysis/MemorySSA.cpp"
, 1959, __PRETTY_FUNCTION__))
;
1960#endif
1961 if (AutoResetWalker)
1962 resetClobberWalker();
1963 return New;
1964}
1965
1966MemoryAccess *MemorySSA::CachingWalker::getClobberingMemoryAccess(
1967 MemoryAccess *StartingAccess, const MemoryLocation &Loc) {
1968 if (isa<MemoryPhi>(StartingAccess))
1969 return StartingAccess;
1970
1971 auto *StartingUseOrDef = cast<MemoryUseOrDef>(StartingAccess);
1972 if (MSSA->isLiveOnEntryDef(StartingUseOrDef))
1973 return StartingUseOrDef;
1974
1975 Instruction *I = StartingUseOrDef->getMemoryInst();
1976
1977 // Conservatively, fences are always clobbers, so don't perform the walk if we
1978 // hit a fence.
1979 if (!ImmutableCallSite(I) && I->isFenceLike())
1980 return StartingUseOrDef;
1981
1982 UpwardsMemoryQuery Q;
1983 Q.OriginalAccess = StartingUseOrDef;
1984 Q.StartingLoc = Loc;
1985 Q.Inst = I;
1986 Q.IsCall = false;
1987
1988 // Unlike the other function, do not walk to the def of a def, because we are
1989 // handed something we already believe is the clobbering access.
1990 MemoryAccess *DefiningAccess = isa<MemoryUse>(StartingUseOrDef)
1991 ? StartingUseOrDef->getDefiningAccess()
1992 : StartingUseOrDef;
1993
1994 MemoryAccess *Clobber = getClobberingMemoryAccess(DefiningAccess, Q);
1995 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)
;
1996 DEBUG(dbgs() << *StartingUseOrDef << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << *StartingUseOrDef << "\n"
; } } while (false)
;
1997 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)
;
1998 DEBUG(dbgs() << *Clobber << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << *Clobber << "\n"; } } while
(false)
;
1999 return Clobber;
2000}
2001
2002MemoryAccess *
2003MemorySSA::CachingWalker::getClobberingMemoryAccess(MemoryAccess *MA) {
2004 auto *StartingAccess = dyn_cast<MemoryUseOrDef>(MA);
2005 // If this is a MemoryPhi, we can't do anything.
2006 if (!StartingAccess)
2007 return MA;
2008
2009 // If this is an already optimized use or def, return the optimized result.
2010 // Note: Currently, we do not store the optimized def result because we'd need
2011 // a separate field, since we can't use it as the defining access.
2012 if (auto *MUD = dyn_cast<MemoryUseOrDef>(StartingAccess))
2013 if (MUD->isOptimized())
2014 return MUD->getOptimized();
2015
2016 const Instruction *I = StartingAccess->getMemoryInst();
2017 UpwardsMemoryQuery Q(I, StartingAccess);
2018 // We can't sanely do anything with a fences, they conservatively
2019 // clobber all memory, and have no locations to get pointers from to
2020 // try to disambiguate.
2021 if (!Q.IsCall && I->isFenceLike())
2022 return StartingAccess;
2023
2024 if (isUseTriviallyOptimizableToLiveOnEntry(*MSSA->AA, I)) {
2025 MemoryAccess *LiveOnEntry = MSSA->getLiveOnEntryDef();
2026 if (auto *MUD = dyn_cast<MemoryUseOrDef>(StartingAccess))
2027 MUD->setOptimized(LiveOnEntry);
2028 return LiveOnEntry;
2029 }
2030
2031 // Start with the thing we already think clobbers this location
2032 MemoryAccess *DefiningAccess = StartingAccess->getDefiningAccess();
2033
2034 // At this point, DefiningAccess may be the live on entry def.
2035 // If it is, we will not get a better result.
2036 if (MSSA->isLiveOnEntryDef(DefiningAccess))
2037 return DefiningAccess;
2038
2039 MemoryAccess *Result = getClobberingMemoryAccess(DefiningAccess, Q);
2040 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)
;
2041 DEBUG(dbgs() << *DefiningAccess << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << *DefiningAccess << "\n"
; } } while (false)
;
2042 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)
;
2043 DEBUG(dbgs() << *Result << "\n")do { if (::llvm::DebugFlag && ::llvm::isCurrentDebugType
("memoryssa")) { dbgs() << *Result << "\n"; } } while
(false)
;
2044 if (auto *MUD = dyn_cast<MemoryUseOrDef>(StartingAccess))
2045 MUD->setOptimized(Result);
2046
2047 return Result;
2048}
2049
2050MemoryAccess *
2051DoNothingMemorySSAWalker::getClobberingMemoryAccess(MemoryAccess *MA) {
2052 if (auto *Use = dyn_cast<MemoryUseOrDef>(MA))
2053 return Use->getDefiningAccess();
2054 return MA;
2055}
2056
2057MemoryAccess *DoNothingMemorySSAWalker::getClobberingMemoryAccess(
2058 MemoryAccess *StartingAccess, const MemoryLocation &) {
2059 if (auto *Use = dyn_cast<MemoryUseOrDef>(StartingAccess))
2060 return Use->getDefiningAccess();
2061 return StartingAccess;
2062}
2063} // namespace llvm
2064
2065void MemoryPhi::deleteMe(DerivedUser *Self) {
2066 delete static_cast<MemoryPhi *>(Self);
2067}
2068
2069void MemoryDef::deleteMe(DerivedUser *Self) {
2070 delete static_cast<MemoryDef *>(Self);
2071}
2072
2073void MemoryUse::deleteMe(DerivedUser *Self) {
2074 delete static_cast<MemoryUse *>(Self);
2075}