1//===- Attributor.cpp - Module-wide attribute deduction -------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements an interprocedural pass that deduces and/or propagates
10// attributes. This is done in an abstract interpretation style fixpoint
11// iteration. See the Attributor.h file comment and the class descriptions in
12// that file for more information.
13//
14//===----------------------------------------------------------------------===//
15
16#include "llvm/Transforms/IPO/Attributor.h"
17
18#include "llvm/ADT/ArrayRef.h"
19#include "llvm/ADT/PointerIntPair.h"
20#include "llvm/ADT/STLExtras.h"
21#include "llvm/ADT/SmallPtrSet.h"
22#include "llvm/ADT/Statistic.h"
23#include "llvm/Analysis/AliasAnalysis.h"
24#include "llvm/Analysis/CallGraph.h"
25#include "llvm/Analysis/CallGraphSCCPass.h"
26#include "llvm/Analysis/InlineCost.h"
27#include "llvm/Analysis/MemoryBuiltins.h"
28#include "llvm/Analysis/MustExecute.h"
29#include "llvm/IR/AttributeMask.h"
30#include "llvm/IR/Attributes.h"
31#include "llvm/IR/Constant.h"
32#include "llvm/IR/ConstantFold.h"
33#include "llvm/IR/Constants.h"
34#include "llvm/IR/DataLayout.h"
35#include "llvm/IR/GlobalValue.h"
36#include "llvm/IR/GlobalVariable.h"
37#include "llvm/IR/Instruction.h"
38#include "llvm/IR/Instructions.h"
39#include "llvm/IR/IntrinsicInst.h"
40#include "llvm/IR/LLVMContext.h"
41#include "llvm/IR/ValueHandle.h"
42#include "llvm/Support/Casting.h"
43#include "llvm/Support/CommandLine.h"
44#include "llvm/Support/Debug.h"
45#include "llvm/Support/DebugCounter.h"
46#include "llvm/Support/FileSystem.h"
47#include "llvm/Support/GraphWriter.h"
48#include "llvm/Support/ModRef.h"
49#include "llvm/Support/raw_ostream.h"
50#include "llvm/Transforms/Utils/BasicBlockUtils.h"
51#include "llvm/Transforms/Utils/Cloning.h"
52#include "llvm/Transforms/Utils/Local.h"
53#include <cstdint>
54#include <memory>
55
56#ifdef EXPENSIVE_CHECKS
57#include "llvm/IR/Verifier.h"
58#endif
59
60#include <cassert>
61#include <optional>
62#include <string>
63
64using namespace llvm;
65
66#define DEBUG_TYPE "attributor"
67#define VERBOSE_DEBUG_TYPE DEBUG_TYPE "-verbose"
68
69DEBUG_COUNTER(ManifestDBGCounter, "attributor-manifest",
70 "Determine what attributes are manifested in the IR");
71
72STATISTIC(NumFnDeleted, "Number of function deleted");
73STATISTIC(NumFnWithExactDefinition,
74 "Number of functions with exact definitions");
75STATISTIC(NumFnWithoutExactDefinition,
76 "Number of functions without exact definitions");
77STATISTIC(NumFnShallowWrappersCreated, "Number of shallow wrappers created");
78STATISTIC(NumAttributesTimedOut,
79 "Number of abstract attributes timed out before fixpoint");
80STATISTIC(NumAttributesValidFixpoint,
81 "Number of abstract attributes in a valid fixpoint state");
82STATISTIC(NumAttributesManifested,
83 "Number of abstract attributes manifested in IR");
84
85// TODO: Determine a good default value.
86//
87// In the LLVM-TS and SPEC2006, 32 seems to not induce compile time overheads
88// (when run with the first 5 abstract attributes). The results also indicate
89// that we never reach 32 iterations but always find a fixpoint sooner.
90//
91// This will become more evolved once we perform two interleaved fixpoint
92// iterations: bottom-up and top-down.
93static cl::opt<unsigned>
94 SetFixpointIterations("attributor-max-iterations", cl::Hidden,
95 cl::desc("Maximal number of fixpoint iterations."),
96 cl::init(Val: 32));
97
98static cl::opt<unsigned>
99 MaxSpecializationPerCB("attributor-max-specializations-per-call-base",
100 cl::Hidden,
101 cl::desc("Maximal number of callees specialized for "
102 "a call base"),
103 cl::init(UINT32_MAX));
104
105static cl::opt<unsigned, true> MaxInitializationChainLengthX(
106 "attributor-max-initialization-chain-length", cl::Hidden,
107 cl::desc(
108 "Maximal number of chained initializations (to avoid stack overflows)"),
109 cl::location(L&: MaxInitializationChainLength), cl::init(Val: 1024));
110unsigned llvm::MaxInitializationChainLength;
111
112static cl::opt<bool> AnnotateDeclarationCallSites(
113 "attributor-annotate-decl-cs", cl::Hidden,
114 cl::desc("Annotate call sites of function declarations."), cl::init(Val: false));
115
116static cl::opt<bool> EnableHeapToStack("enable-heap-to-stack-conversion",
117 cl::init(Val: true), cl::Hidden);
118
119static cl::opt<bool>
120 AllowShallowWrappers("attributor-allow-shallow-wrappers", cl::Hidden,
121 cl::desc("Allow the Attributor to create shallow "
122 "wrappers for non-exact definitions."),
123 cl::init(Val: false));
124
125static cl::opt<bool>
126 AllowDeepWrapper("attributor-allow-deep-wrappers", cl::Hidden,
127 cl::desc("Allow the Attributor to use IP information "
128 "derived from non-exact functions via cloning"),
129 cl::init(Val: false));
130
131// These options can only used for debug builds.
132#ifndef NDEBUG
133static cl::list<std::string>
134 SeedAllowList("attributor-seed-allow-list", cl::Hidden,
135 cl::desc("Comma seperated list of attribute names that are "
136 "allowed to be seeded."),
137 cl::CommaSeparated);
138
139static cl::list<std::string> FunctionSeedAllowList(
140 "attributor-function-seed-allow-list", cl::Hidden,
141 cl::desc("Comma seperated list of function names that are "
142 "allowed to be seeded."),
143 cl::CommaSeparated);
144#endif
145
146static cl::opt<bool>
147 DumpDepGraph("attributor-dump-dep-graph", cl::Hidden,
148 cl::desc("Dump the dependency graph to dot files."),
149 cl::init(Val: false));
150
151static cl::opt<std::string> DepGraphDotFileNamePrefix(
152 "attributor-depgraph-dot-filename-prefix", cl::Hidden,
153 cl::desc("The prefix used for the CallGraph dot file names."));
154
155static cl::opt<bool> ViewDepGraph("attributor-view-dep-graph", cl::Hidden,
156 cl::desc("View the dependency graph."),
157 cl::init(Val: false));
158
159static cl::opt<bool> PrintDependencies("attributor-print-dep", cl::Hidden,
160 cl::desc("Print attribute dependencies"),
161 cl::init(Val: false));
162
163static cl::opt<bool> EnableCallSiteSpecific(
164 "attributor-enable-call-site-specific-deduction", cl::Hidden,
165 cl::desc("Allow the Attributor to do call site specific analysis"),
166 cl::init(Val: false));
167
168static cl::opt<bool>
169 PrintCallGraph("attributor-print-call-graph", cl::Hidden,
170 cl::desc("Print Attributor's internal call graph"),
171 cl::init(Val: false));
172
173static cl::opt<bool> SimplifyAllLoads("attributor-simplify-all-loads",
174 cl::Hidden,
175 cl::desc("Try to simplify all loads."),
176 cl::init(Val: true));
177
178static cl::opt<bool> CloseWorldAssumption(
179 "attributor-assume-closed-world", cl::Hidden,
180 cl::desc("Should a closed world be assumed, or not. Default if not set."));
181
182/// Logic operators for the change status enum class.
183///
184///{
185ChangeStatus llvm::operator|(ChangeStatus L, ChangeStatus R) {
186 return L == ChangeStatus::CHANGED ? L : R;
187}
188ChangeStatus &llvm::operator|=(ChangeStatus &L, ChangeStatus R) {
189 L = L | R;
190 return L;
191}
192ChangeStatus llvm::operator&(ChangeStatus L, ChangeStatus R) {
193 return L == ChangeStatus::UNCHANGED ? L : R;
194}
195ChangeStatus &llvm::operator&=(ChangeStatus &L, ChangeStatus R) {
196 L = L & R;
197 return L;
198}
199///}
200
201bool AA::isGPU(const Module &M) {
202 Triple T(M.getTargetTriple());
203 return T.isAMDGPU() || T.isNVPTX();
204}
205
206bool AA::isNoSyncInst(Attributor &A, const Instruction &I,
207 const AbstractAttribute &QueryingAA) {
208 // We are looking for volatile instructions or non-relaxed atomics.
209 if (const auto *CB = dyn_cast<CallBase>(Val: &I)) {
210 if (CB->hasFnAttr(Attribute::NoSync))
211 return true;
212
213 // Non-convergent and readnone imply nosync.
214 if (!CB->isConvergent() && !CB->mayReadOrWriteMemory())
215 return true;
216
217 if (AANoSync::isNoSyncIntrinsic(I: &I))
218 return true;
219
220 bool IsKnownNoSync;
221 return AA::hasAssumedIRAttr<Attribute::NoSync>(
222 A, &QueryingAA, IRPosition::callsite_function(*CB),
223 DepClassTy::OPTIONAL, IsKnownNoSync);
224 }
225
226 if (!I.mayReadOrWriteMemory())
227 return true;
228
229 return !I.isVolatile() && !AANoSync::isNonRelaxedAtomic(I: &I);
230}
231
232bool AA::isDynamicallyUnique(Attributor &A, const AbstractAttribute &QueryingAA,
233 const Value &V, bool ForAnalysisOnly) {
234 // TODO: See the AAInstanceInfo class comment.
235 if (!ForAnalysisOnly)
236 return false;
237 auto *InstanceInfoAA = A.getAAFor<AAInstanceInfo>(
238 QueryingAA, IRP: IRPosition::value(V), DepClass: DepClassTy::OPTIONAL);
239 return InstanceInfoAA && InstanceInfoAA->isAssumedUniqueForAnalysis();
240}
241
242Constant *
243AA::getInitialValueForObj(Attributor &A, const AbstractAttribute &QueryingAA,
244 Value &Obj, Type &Ty, const TargetLibraryInfo *TLI,
245 const DataLayout &DL, AA::RangeTy *RangePtr) {
246 if (isa<AllocaInst>(Val: Obj))
247 return UndefValue::get(T: &Ty);
248 if (Constant *Init = getInitialValueOfAllocation(V: &Obj, TLI, Ty: &Ty))
249 return Init;
250 auto *GV = dyn_cast<GlobalVariable>(Val: &Obj);
251 if (!GV)
252 return nullptr;
253
254 bool UsedAssumedInformation = false;
255 Constant *Initializer = nullptr;
256 if (A.hasGlobalVariableSimplificationCallback(GV: *GV)) {
257 auto AssumedGV = A.getAssumedInitializerFromCallBack(
258 GV: *GV, AA: &QueryingAA, UsedAssumedInformation);
259 Initializer = *AssumedGV;
260 if (!Initializer)
261 return nullptr;
262 } else {
263 if (!GV->hasLocalLinkage() &&
264 (GV->isInterposable() || !(GV->isConstant() && GV->hasInitializer())))
265 return nullptr;
266 if (!GV->hasInitializer())
267 return UndefValue::get(T: &Ty);
268
269 if (!Initializer)
270 Initializer = GV->getInitializer();
271 }
272
273 if (RangePtr && !RangePtr->offsetOrSizeAreUnknown()) {
274 APInt Offset = APInt(64, RangePtr->Offset);
275 return ConstantFoldLoadFromConst(C: Initializer, Ty: &Ty, Offset, DL);
276 }
277
278 return ConstantFoldLoadFromUniformValue(C: Initializer, Ty: &Ty, DL);
279}
280
281bool AA::isValidInScope(const Value &V, const Function *Scope) {
282 if (isa<Constant>(Val: V))
283 return true;
284 if (auto *I = dyn_cast<Instruction>(Val: &V))
285 return I->getFunction() == Scope;
286 if (auto *A = dyn_cast<Argument>(Val: &V))
287 return A->getParent() == Scope;
288 return false;
289}
290
291bool AA::isValidAtPosition(const AA::ValueAndContext &VAC,
292 InformationCache &InfoCache) {
293 if (isa<Constant>(Val: VAC.getValue()) || VAC.getValue() == VAC.getCtxI())
294 return true;
295 const Function *Scope = nullptr;
296 const Instruction *CtxI = VAC.getCtxI();
297 if (CtxI)
298 Scope = CtxI->getFunction();
299 if (auto *A = dyn_cast<Argument>(Val: VAC.getValue()))
300 return A->getParent() == Scope;
301 if (auto *I = dyn_cast<Instruction>(Val: VAC.getValue())) {
302 if (I->getFunction() == Scope) {
303 if (const DominatorTree *DT =
304 InfoCache.getAnalysisResultForFunction<DominatorTreeAnalysis>(
305 F: *Scope))
306 return DT->dominates(Def: I, User: CtxI);
307 // Local dominance check mostly for the old PM passes.
308 if (CtxI && I->getParent() == CtxI->getParent())
309 return llvm::any_of(
310 Range: make_range(x: I->getIterator(), y: I->getParent()->end()),
311 P: [&](const Instruction &AfterI) { return &AfterI == CtxI; });
312 }
313 }
314 return false;
315}
316
317Value *AA::getWithType(Value &V, Type &Ty) {
318 if (V.getType() == &Ty)
319 return &V;
320 if (isa<PoisonValue>(Val: V))
321 return PoisonValue::get(T: &Ty);
322 if (isa<UndefValue>(Val: V))
323 return UndefValue::get(T: &Ty);
324 if (auto *C = dyn_cast<Constant>(Val: &V)) {
325 if (C->isNullValue())
326 return Constant::getNullValue(Ty: &Ty);
327 if (C->getType()->isPointerTy() && Ty.isPointerTy())
328 return ConstantExpr::getPointerCast(C, Ty: &Ty);
329 if (C->getType()->getPrimitiveSizeInBits() >= Ty.getPrimitiveSizeInBits()) {
330 if (C->getType()->isIntegerTy() && Ty.isIntegerTy())
331 return ConstantExpr::getTrunc(C, Ty: &Ty, /* OnlyIfReduced */ true);
332 if (C->getType()->isFloatingPointTy() && Ty.isFloatingPointTy())
333 return ConstantFoldCastInstruction(opcode: Instruction::FPTrunc, V: C, DestTy: &Ty);
334 }
335 }
336 return nullptr;
337}
338
339std::optional<Value *>
340AA::combineOptionalValuesInAAValueLatice(const std::optional<Value *> &A,
341 const std::optional<Value *> &B,
342 Type *Ty) {
343 if (A == B)
344 return A;
345 if (!B)
346 return A;
347 if (*B == nullptr)
348 return nullptr;
349 if (!A)
350 return Ty ? getWithType(V&: **B, Ty&: *Ty) : nullptr;
351 if (*A == nullptr)
352 return nullptr;
353 if (!Ty)
354 Ty = (*A)->getType();
355 if (isa_and_nonnull<UndefValue>(Val: *A))
356 return getWithType(V&: **B, Ty&: *Ty);
357 if (isa<UndefValue>(Val: *B))
358 return A;
359 if (*A && *B && *A == getWithType(V&: **B, Ty&: *Ty))
360 return A;
361 return nullptr;
362}
363
364template <bool IsLoad, typename Ty>
365static bool getPotentialCopiesOfMemoryValue(
366 Attributor &A, Ty &I, SmallSetVector<Value *, 4> &PotentialCopies,
367 SmallSetVector<Instruction *, 4> *PotentialValueOrigins,
368 const AbstractAttribute &QueryingAA, bool &UsedAssumedInformation,
369 bool OnlyExact) {
370 LLVM_DEBUG(dbgs() << "Trying to determine the potential copies of " << I
371 << " (only exact: " << OnlyExact << ")\n";);
372
373 Value &Ptr = *I.getPointerOperand();
374 // Containers to remember the pointer infos and new copies while we are not
375 // sure that we can find all of them. If we abort we want to avoid spurious
376 // dependences and potential copies in the provided container.
377 SmallVector<const AAPointerInfo *> PIs;
378 SmallSetVector<Value *, 8> NewCopies;
379 SmallSetVector<Instruction *, 8> NewCopyOrigins;
380
381 const auto *TLI =
382 A.getInfoCache().getTargetLibraryInfoForFunction(F: *I.getFunction());
383
384 auto Pred = [&](Value &Obj) {
385 LLVM_DEBUG(dbgs() << "Visit underlying object " << Obj << "\n");
386 if (isa<UndefValue>(Val: &Obj))
387 return true;
388 if (isa<ConstantPointerNull>(Val: &Obj)) {
389 // A null pointer access can be undefined but any offset from null may
390 // be OK. We do not try to optimize the latter.
391 if (!NullPointerIsDefined(I.getFunction(),
392 Ptr.getType()->getPointerAddressSpace()) &&
393 A.getAssumedSimplified(V: Ptr, AA: QueryingAA, UsedAssumedInformation,
394 S: AA::Interprocedural) == &Obj)
395 return true;
396 LLVM_DEBUG(
397 dbgs() << "Underlying object is a valid nullptr, giving up.\n";);
398 return false;
399 }
400 // TODO: Use assumed noalias return.
401 if (!isa<AllocaInst>(Val: &Obj) && !isa<GlobalVariable>(Val: &Obj) &&
402 !(IsLoad ? isAllocationFn(&Obj, TLI) : isNoAliasCall(V: &Obj))) {
403 LLVM_DEBUG(dbgs() << "Underlying object is not supported yet: " << Obj
404 << "\n";);
405 return false;
406 }
407 if (auto *GV = dyn_cast<GlobalVariable>(Val: &Obj))
408 if (!GV->hasLocalLinkage() &&
409 !(GV->isConstant() && GV->hasInitializer())) {
410 LLVM_DEBUG(dbgs() << "Underlying object is global with external "
411 "linkage, not supported yet: "
412 << Obj << "\n";);
413 return false;
414 }
415
416 bool NullOnly = true;
417 bool NullRequired = false;
418 auto CheckForNullOnlyAndUndef = [&](std::optional<Value *> V,
419 bool IsExact) {
420 if (!V || *V == nullptr)
421 NullOnly = false;
422 else if (isa<UndefValue>(Val: *V))
423 /* No op */;
424 else if (isa<Constant>(Val: *V) && cast<Constant>(Val: *V)->isNullValue())
425 NullRequired = !IsExact;
426 else
427 NullOnly = false;
428 };
429
430 auto AdjustWrittenValueType = [&](const AAPointerInfo::Access &Acc,
431 Value &V) {
432 Value *AdjV = AA::getWithType(V, Ty&: *I.getType());
433 if (!AdjV) {
434 LLVM_DEBUG(dbgs() << "Underlying object written but stored value "
435 "cannot be converted to read type: "
436 << *Acc.getRemoteInst() << " : " << *I.getType()
437 << "\n";);
438 }
439 return AdjV;
440 };
441
442 auto SkipCB = [&](const AAPointerInfo::Access &Acc) {
443 if ((IsLoad && !Acc.isWriteOrAssumption()) || (!IsLoad && !Acc.isRead()))
444 return true;
445 if (IsLoad) {
446 if (Acc.isWrittenValueYetUndetermined())
447 return true;
448 if (PotentialValueOrigins && !isa<AssumeInst>(Val: Acc.getRemoteInst()))
449 return false;
450 if (!Acc.isWrittenValueUnknown())
451 if (Value *V = AdjustWrittenValueType(Acc, *Acc.getWrittenValue()))
452 if (NewCopies.count(key: V)) {
453 NewCopyOrigins.insert(X: Acc.getRemoteInst());
454 return true;
455 }
456 if (auto *SI = dyn_cast<StoreInst>(Val: Acc.getRemoteInst()))
457 if (Value *V = AdjustWrittenValueType(Acc, *SI->getValueOperand()))
458 if (NewCopies.count(key: V)) {
459 NewCopyOrigins.insert(X: Acc.getRemoteInst());
460 return true;
461 }
462 }
463 return false;
464 };
465
466 auto CheckAccess = [&](const AAPointerInfo::Access &Acc, bool IsExact) {
467 if ((IsLoad && !Acc.isWriteOrAssumption()) || (!IsLoad && !Acc.isRead()))
468 return true;
469 if (IsLoad && Acc.isWrittenValueYetUndetermined())
470 return true;
471 CheckForNullOnlyAndUndef(Acc.getContent(), IsExact);
472 if (OnlyExact && !IsExact && !NullOnly &&
473 !isa_and_nonnull<UndefValue>(Val: Acc.getWrittenValue())) {
474 LLVM_DEBUG(dbgs() << "Non exact access " << *Acc.getRemoteInst()
475 << ", abort!\n");
476 return false;
477 }
478 if (NullRequired && !NullOnly) {
479 LLVM_DEBUG(dbgs() << "Required all `null` accesses due to non exact "
480 "one, however found non-null one: "
481 << *Acc.getRemoteInst() << ", abort!\n");
482 return false;
483 }
484 if (IsLoad) {
485 assert(isa<LoadInst>(I) && "Expected load or store instruction only!");
486 if (!Acc.isWrittenValueUnknown()) {
487 Value *V = AdjustWrittenValueType(Acc, *Acc.getWrittenValue());
488 if (!V)
489 return false;
490 NewCopies.insert(X: V);
491 if (PotentialValueOrigins)
492 NewCopyOrigins.insert(X: Acc.getRemoteInst());
493 return true;
494 }
495 auto *SI = dyn_cast<StoreInst>(Val: Acc.getRemoteInst());
496 if (!SI) {
497 LLVM_DEBUG(dbgs() << "Underlying object written through a non-store "
498 "instruction not supported yet: "
499 << *Acc.getRemoteInst() << "\n";);
500 return false;
501 }
502 Value *V = AdjustWrittenValueType(Acc, *SI->getValueOperand());
503 if (!V)
504 return false;
505 NewCopies.insert(X: V);
506 if (PotentialValueOrigins)
507 NewCopyOrigins.insert(X: SI);
508 } else {
509 assert(isa<StoreInst>(I) && "Expected load or store instruction only!");
510 auto *LI = dyn_cast<LoadInst>(Val: Acc.getRemoteInst());
511 if (!LI && OnlyExact) {
512 LLVM_DEBUG(dbgs() << "Underlying object read through a non-load "
513 "instruction not supported yet: "
514 << *Acc.getRemoteInst() << "\n";);
515 return false;
516 }
517 NewCopies.insert(X: Acc.getRemoteInst());
518 }
519 return true;
520 };
521
522 // If the value has been written to we don't need the initial value of the
523 // object.
524 bool HasBeenWrittenTo = false;
525
526 AA::RangeTy Range;
527 auto *PI = A.getAAFor<AAPointerInfo>(QueryingAA, IRP: IRPosition::value(V: Obj),
528 DepClass: DepClassTy::NONE);
529 if (!PI || !PI->forallInterferingAccesses(
530 A, QueryingAA, I,
531 /* FindInterferingWrites */ IsLoad,
532 /* FindInterferingReads */ !IsLoad, CheckAccess,
533 HasBeenWrittenTo, Range, SkipCB)) {
534 LLVM_DEBUG(
535 dbgs()
536 << "Failed to verify all interfering accesses for underlying object: "
537 << Obj << "\n");
538 return false;
539 }
540
541 if (IsLoad && !HasBeenWrittenTo && !Range.isUnassigned()) {
542 const DataLayout &DL = A.getDataLayout();
543 Value *InitialValue = AA::getInitialValueForObj(
544 A, QueryingAA, Obj, Ty&: *I.getType(), TLI, DL, RangePtr: &Range);
545 if (!InitialValue) {
546 LLVM_DEBUG(dbgs() << "Could not determine required initial value of "
547 "underlying object, abort!\n");
548 return false;
549 }
550 CheckForNullOnlyAndUndef(InitialValue, /* IsExact */ true);
551 if (NullRequired && !NullOnly) {
552 LLVM_DEBUG(dbgs() << "Non exact access but initial value that is not "
553 "null or undef, abort!\n");
554 return false;
555 }
556
557 NewCopies.insert(X: InitialValue);
558 if (PotentialValueOrigins)
559 NewCopyOrigins.insert(X: nullptr);
560 }
561
562 PIs.push_back(Elt: PI);
563
564 return true;
565 };
566
567 const auto *AAUO = A.getAAFor<AAUnderlyingObjects>(
568 QueryingAA, IRP: IRPosition::value(V: Ptr), DepClass: DepClassTy::OPTIONAL);
569 if (!AAUO || !AAUO->forallUnderlyingObjects(Pred)) {
570 LLVM_DEBUG(
571 dbgs() << "Underlying objects stored into could not be determined\n";);
572 return false;
573 }
574
575 // Only if we were successful collection all potential copies we record
576 // dependences (on non-fix AAPointerInfo AAs). We also only then modify the
577 // given PotentialCopies container.
578 for (const auto *PI : PIs) {
579 if (!PI->getState().isAtFixpoint())
580 UsedAssumedInformation = true;
581 A.recordDependence(FromAA: *PI, ToAA: QueryingAA, DepClass: DepClassTy::OPTIONAL);
582 }
583 PotentialCopies.insert(Start: NewCopies.begin(), End: NewCopies.end());
584 if (PotentialValueOrigins)
585 PotentialValueOrigins->insert(Start: NewCopyOrigins.begin(), End: NewCopyOrigins.end());
586
587 return true;
588}
589
590bool AA::getPotentiallyLoadedValues(
591 Attributor &A, LoadInst &LI, SmallSetVector<Value *, 4> &PotentialValues,
592 SmallSetVector<Instruction *, 4> &PotentialValueOrigins,
593 const AbstractAttribute &QueryingAA, bool &UsedAssumedInformation,
594 bool OnlyExact) {
595 return getPotentialCopiesOfMemoryValue</* IsLoad */ true>(
596 A, I&: LI, PotentialCopies&: PotentialValues, PotentialValueOrigins: &PotentialValueOrigins, QueryingAA,
597 UsedAssumedInformation, OnlyExact);
598}
599
600bool AA::getPotentialCopiesOfStoredValue(
601 Attributor &A, StoreInst &SI, SmallSetVector<Value *, 4> &PotentialCopies,
602 const AbstractAttribute &QueryingAA, bool &UsedAssumedInformation,
603 bool OnlyExact) {
604 return getPotentialCopiesOfMemoryValue</* IsLoad */ false>(
605 A, I&: SI, PotentialCopies, PotentialValueOrigins: nullptr, QueryingAA, UsedAssumedInformation,
606 OnlyExact);
607}
608
609static bool isAssumedReadOnlyOrReadNone(Attributor &A, const IRPosition &IRP,
610 const AbstractAttribute &QueryingAA,
611 bool RequireReadNone, bool &IsKnown) {
612 if (RequireReadNone) {
613 if (AA::hasAssumedIRAttr<Attribute::ReadNone>(
614 A, &QueryingAA, IRP, DepClassTy::OPTIONAL, IsKnown,
615 /* IgnoreSubsumingPositions */ true))
616 return true;
617 } else if (AA::hasAssumedIRAttr<Attribute::ReadOnly>(
618 A, &QueryingAA, IRP, DepClassTy::OPTIONAL, IsKnown,
619 /* IgnoreSubsumingPositions */ true))
620 return true;
621
622 IRPosition::Kind Kind = IRP.getPositionKind();
623 if (Kind == IRPosition::IRP_FUNCTION || Kind == IRPosition::IRP_CALL_SITE) {
624 const auto *MemLocAA =
625 A.getAAFor<AAMemoryLocation>(QueryingAA, IRP, DepClass: DepClassTy::NONE);
626 if (MemLocAA && MemLocAA->isAssumedReadNone()) {
627 IsKnown = MemLocAA->isKnownReadNone();
628 if (!IsKnown)
629 A.recordDependence(FromAA: *MemLocAA, ToAA: QueryingAA, DepClass: DepClassTy::OPTIONAL);
630 return true;
631 }
632 }
633
634 const auto *MemBehaviorAA =
635 A.getAAFor<AAMemoryBehavior>(QueryingAA, IRP, DepClass: DepClassTy::NONE);
636 if (MemBehaviorAA &&
637 (MemBehaviorAA->isAssumedReadNone() ||
638 (!RequireReadNone && MemBehaviorAA->isAssumedReadOnly()))) {
639 IsKnown = RequireReadNone ? MemBehaviorAA->isKnownReadNone()
640 : MemBehaviorAA->isKnownReadOnly();
641 if (!IsKnown)
642 A.recordDependence(FromAA: *MemBehaviorAA, ToAA: QueryingAA, DepClass: DepClassTy::OPTIONAL);
643 return true;
644 }
645
646 return false;
647}
648
649bool AA::isAssumedReadOnly(Attributor &A, const IRPosition &IRP,
650 const AbstractAttribute &QueryingAA, bool &IsKnown) {
651 return isAssumedReadOnlyOrReadNone(A, IRP, QueryingAA,
652 /* RequireReadNone */ false, IsKnown);
653}
654bool AA::isAssumedReadNone(Attributor &A, const IRPosition &IRP,
655 const AbstractAttribute &QueryingAA, bool &IsKnown) {
656 return isAssumedReadOnlyOrReadNone(A, IRP, QueryingAA,
657 /* RequireReadNone */ true, IsKnown);
658}
659
660static bool
661isPotentiallyReachable(Attributor &A, const Instruction &FromI,
662 const Instruction *ToI, const Function &ToFn,
663 const AbstractAttribute &QueryingAA,
664 const AA::InstExclusionSetTy *ExclusionSet,
665 std::function<bool(const Function &F)> GoBackwardsCB) {
666 DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE, {
667 dbgs() << "[AA] isPotentiallyReachable @" << ToFn.getName() << " from "
668 << FromI << " [GBCB: " << bool(GoBackwardsCB) << "][#ExS: "
669 << (ExclusionSet ? std::to_string(ExclusionSet->size()) : "none")
670 << "]\n";
671 if (ExclusionSet)
672 for (auto *ES : *ExclusionSet)
673 dbgs() << *ES << "\n";
674 });
675
676 // We know kernels (generally) cannot be called from within the module. Thus,
677 // for reachability we would need to step back from a kernel which would allow
678 // us to reach anything anyway. Even if a kernel is invoked from another
679 // kernel, values like allocas and shared memory are not accessible. We
680 // implicitly check for this situation to avoid costly lookups.
681 if (GoBackwardsCB && &ToFn != FromI.getFunction() &&
682 !GoBackwardsCB(*FromI.getFunction()) && ToFn.hasFnAttribute(Kind: "kernel") &&
683 FromI.getFunction()->hasFnAttribute(Kind: "kernel")) {
684 LLVM_DEBUG(dbgs() << "[AA] assume kernel cannot be reached from within the "
685 "module; success\n";);
686 return false;
687 }
688
689 // If we can go arbitrarily backwards we will eventually reach an entry point
690 // that can reach ToI. Only if a set of blocks through which we cannot go is
691 // provided, or once we track internal functions not accessible from the
692 // outside, it makes sense to perform backwards analysis in the absence of a
693 // GoBackwardsCB.
694 if (!GoBackwardsCB && !ExclusionSet) {
695 LLVM_DEBUG(dbgs() << "[AA] check @" << ToFn.getName() << " from " << FromI
696 << " is not checked backwards and does not have an "
697 "exclusion set, abort\n");
698 return true;
699 }
700
701 SmallPtrSet<const Instruction *, 8> Visited;
702 SmallVector<const Instruction *> Worklist;
703 Worklist.push_back(Elt: &FromI);
704
705 while (!Worklist.empty()) {
706 const Instruction *CurFromI = Worklist.pop_back_val();
707 if (!Visited.insert(Ptr: CurFromI).second)
708 continue;
709
710 const Function *FromFn = CurFromI->getFunction();
711 if (FromFn == &ToFn) {
712 if (!ToI)
713 return true;
714 LLVM_DEBUG(dbgs() << "[AA] check " << *ToI << " from " << *CurFromI
715 << " intraprocedurally\n");
716 const auto *ReachabilityAA = A.getAAFor<AAIntraFnReachability>(
717 QueryingAA, IRP: IRPosition::function(F: ToFn), DepClass: DepClassTy::OPTIONAL);
718 bool Result = !ReachabilityAA || ReachabilityAA->isAssumedReachable(
719 A, From: *CurFromI, To: *ToI, ExclusionSet);
720 LLVM_DEBUG(dbgs() << "[AA] " << *CurFromI << " "
721 << (Result ? "can potentially " : "cannot ") << "reach "
722 << *ToI << " [Intra]\n");
723 if (Result)
724 return true;
725 }
726
727 bool Result = true;
728 if (!ToFn.isDeclaration() && ToI) {
729 const auto *ToReachabilityAA = A.getAAFor<AAIntraFnReachability>(
730 QueryingAA, IRP: IRPosition::function(F: ToFn), DepClass: DepClassTy::OPTIONAL);
731 const Instruction &EntryI = ToFn.getEntryBlock().front();
732 Result = !ToReachabilityAA || ToReachabilityAA->isAssumedReachable(
733 A, From: EntryI, To: *ToI, ExclusionSet);
734 LLVM_DEBUG(dbgs() << "[AA] Entry " << EntryI << " of @" << ToFn.getName()
735 << " " << (Result ? "can potentially " : "cannot ")
736 << "reach @" << *ToI << " [ToFn]\n");
737 }
738
739 if (Result) {
740 // The entry of the ToFn can reach the instruction ToI. If the current
741 // instruction is already known to reach the ToFn.
742 const auto *FnReachabilityAA = A.getAAFor<AAInterFnReachability>(
743 QueryingAA, IRP: IRPosition::function(F: *FromFn), DepClass: DepClassTy::OPTIONAL);
744 Result = !FnReachabilityAA || FnReachabilityAA->instructionCanReach(
745 A, Inst: *CurFromI, Fn: ToFn, ExclusionSet);
746 LLVM_DEBUG(dbgs() << "[AA] " << *CurFromI << " in @" << FromFn->getName()
747 << " " << (Result ? "can potentially " : "cannot ")
748 << "reach @" << ToFn.getName() << " [FromFn]\n");
749 if (Result)
750 return true;
751 }
752
753 // TODO: Check assumed nounwind.
754 const auto *ReachabilityAA = A.getAAFor<AAIntraFnReachability>(
755 QueryingAA, IRP: IRPosition::function(F: *FromFn), DepClass: DepClassTy::OPTIONAL);
756 auto ReturnInstCB = [&](Instruction &Ret) {
757 bool Result = !ReachabilityAA || ReachabilityAA->isAssumedReachable(
758 A, From: *CurFromI, To: Ret, ExclusionSet);
759 LLVM_DEBUG(dbgs() << "[AA][Ret] " << *CurFromI << " "
760 << (Result ? "can potentially " : "cannot ") << "reach "
761 << Ret << " [Intra]\n");
762 return !Result;
763 };
764
765 // Check if we can reach returns.
766 bool UsedAssumedInformation = false;
767 if (A.checkForAllInstructions(Pred: ReturnInstCB, Fn: FromFn, QueryingAA: &QueryingAA,
768 Opcodes: {Instruction::Ret}, UsedAssumedInformation)) {
769 LLVM_DEBUG(dbgs() << "[AA] No return is reachable, done\n");
770 continue;
771 }
772
773 if (!GoBackwardsCB) {
774 LLVM_DEBUG(dbgs() << "[AA] check @" << ToFn.getName() << " from " << FromI
775 << " is not checked backwards, abort\n");
776 return true;
777 }
778
779 // If we do not go backwards from the FromFn we are done here and so far we
780 // could not find a way to reach ToFn/ToI.
781 if (!GoBackwardsCB(*FromFn))
782 continue;
783
784 LLVM_DEBUG(dbgs() << "Stepping backwards to the call sites of @"
785 << FromFn->getName() << "\n");
786
787 auto CheckCallSite = [&](AbstractCallSite ACS) {
788 CallBase *CB = ACS.getInstruction();
789 if (!CB)
790 return false;
791
792 if (isa<InvokeInst>(Val: CB))
793 return false;
794
795 Instruction *Inst = CB->getNextNonDebugInstruction();
796 Worklist.push_back(Elt: Inst);
797 return true;
798 };
799
800 Result = !A.checkForAllCallSites(Pred: CheckCallSite, Fn: *FromFn,
801 /* RequireAllCallSites */ true,
802 QueryingAA: &QueryingAA, UsedAssumedInformation);
803 if (Result) {
804 LLVM_DEBUG(dbgs() << "[AA] stepping back to call sites from " << *CurFromI
805 << " in @" << FromFn->getName()
806 << " failed, give up\n");
807 return true;
808 }
809
810 LLVM_DEBUG(dbgs() << "[AA] stepped back to call sites from " << *CurFromI
811 << " in @" << FromFn->getName()
812 << " worklist size is: " << Worklist.size() << "\n");
813 }
814 return false;
815}
816
817bool AA::isPotentiallyReachable(
818 Attributor &A, const Instruction &FromI, const Instruction &ToI,
819 const AbstractAttribute &QueryingAA,
820 const AA::InstExclusionSetTy *ExclusionSet,
821 std::function<bool(const Function &F)> GoBackwardsCB) {
822 const Function *ToFn = ToI.getFunction();
823 return ::isPotentiallyReachable(A, FromI, ToI: &ToI, ToFn: *ToFn, QueryingAA,
824 ExclusionSet, GoBackwardsCB);
825}
826
827bool AA::isPotentiallyReachable(
828 Attributor &A, const Instruction &FromI, const Function &ToFn,
829 const AbstractAttribute &QueryingAA,
830 const AA::InstExclusionSetTy *ExclusionSet,
831 std::function<bool(const Function &F)> GoBackwardsCB) {
832 return ::isPotentiallyReachable(A, FromI, /* ToI */ nullptr, ToFn, QueryingAA,
833 ExclusionSet, GoBackwardsCB);
834}
835
836bool AA::isAssumedThreadLocalObject(Attributor &A, Value &Obj,
837 const AbstractAttribute &QueryingAA) {
838 if (isa<UndefValue>(Val: Obj))
839 return true;
840 if (isa<AllocaInst>(Val: Obj)) {
841 InformationCache &InfoCache = A.getInfoCache();
842 if (!InfoCache.stackIsAccessibleByOtherThreads()) {
843 LLVM_DEBUG(
844 dbgs() << "[AA] Object '" << Obj
845 << "' is thread local; stack objects are thread local.\n");
846 return true;
847 }
848 bool IsKnownNoCapture;
849 bool IsAssumedNoCapture = AA::hasAssumedIRAttr<Attribute::NoCapture>(
850 A, &QueryingAA, IRPosition::value(Obj), DepClassTy::OPTIONAL,
851 IsKnownNoCapture);
852 LLVM_DEBUG(dbgs() << "[AA] Object '" << Obj << "' is "
853 << (IsAssumedNoCapture ? "" : "not") << " thread local; "
854 << (IsAssumedNoCapture ? "non-" : "")
855 << "captured stack object.\n");
856 return IsAssumedNoCapture;
857 }
858 if (auto *GV = dyn_cast<GlobalVariable>(Val: &Obj)) {
859 if (GV->isConstant()) {
860 LLVM_DEBUG(dbgs() << "[AA] Object '" << Obj
861 << "' is thread local; constant global\n");
862 return true;
863 }
864 if (GV->isThreadLocal()) {
865 LLVM_DEBUG(dbgs() << "[AA] Object '" << Obj
866 << "' is thread local; thread local global\n");
867 return true;
868 }
869 }
870
871 if (A.getInfoCache().targetIsGPU()) {
872 if (Obj.getType()->getPointerAddressSpace() ==
873 (int)AA::GPUAddressSpace::Local) {
874 LLVM_DEBUG(dbgs() << "[AA] Object '" << Obj
875 << "' is thread local; GPU local memory\n");
876 return true;
877 }
878 if (Obj.getType()->getPointerAddressSpace() ==
879 (int)AA::GPUAddressSpace::Constant) {
880 LLVM_DEBUG(dbgs() << "[AA] Object '" << Obj
881 << "' is thread local; GPU constant memory\n");
882 return true;
883 }
884 }
885
886 LLVM_DEBUG(dbgs() << "[AA] Object '" << Obj << "' is not thread local\n");
887 return false;
888}
889
890bool AA::isPotentiallyAffectedByBarrier(Attributor &A, const Instruction &I,
891 const AbstractAttribute &QueryingAA) {
892 if (!I.mayHaveSideEffects() && !I.mayReadFromMemory())
893 return false;
894
895 SmallSetVector<const Value *, 8> Ptrs;
896
897 auto AddLocationPtr = [&](std::optional<MemoryLocation> Loc) {
898 if (!Loc || !Loc->Ptr) {
899 LLVM_DEBUG(
900 dbgs() << "[AA] Access to unknown location; -> requires barriers\n");
901 return false;
902 }
903 Ptrs.insert(X: Loc->Ptr);
904 return true;
905 };
906
907 if (const MemIntrinsic *MI = dyn_cast<MemIntrinsic>(Val: &I)) {
908 if (!AddLocationPtr(MemoryLocation::getForDest(MI)))
909 return true;
910 if (const MemTransferInst *MTI = dyn_cast<MemTransferInst>(Val: &I))
911 if (!AddLocationPtr(MemoryLocation::getForSource(MTI)))
912 return true;
913 } else if (!AddLocationPtr(MemoryLocation::getOrNone(Inst: &I)))
914 return true;
915
916 return isPotentiallyAffectedByBarrier(A, Ptrs: Ptrs.getArrayRef(), QueryingAA, CtxI: &I);
917}
918
919bool AA::isPotentiallyAffectedByBarrier(Attributor &A,
920 ArrayRef<const Value *> Ptrs,
921 const AbstractAttribute &QueryingAA,
922 const Instruction *CtxI) {
923 for (const Value *Ptr : Ptrs) {
924 if (!Ptr) {
925 LLVM_DEBUG(dbgs() << "[AA] nullptr; -> requires barriers\n");
926 return true;
927 }
928
929 auto Pred = [&](Value &Obj) {
930 if (AA::isAssumedThreadLocalObject(A, Obj, QueryingAA))
931 return true;
932 LLVM_DEBUG(dbgs() << "[AA] Access to '" << Obj << "' via '" << *Ptr
933 << "'; -> requires barrier\n");
934 return false;
935 };
936
937 const auto *UnderlyingObjsAA = A.getAAFor<AAUnderlyingObjects>(
938 QueryingAA, IRP: IRPosition::value(V: *Ptr), DepClass: DepClassTy::OPTIONAL);
939 if (!UnderlyingObjsAA || !UnderlyingObjsAA->forallUnderlyingObjects(Pred))
940 return true;
941 }
942 return false;
943}
944
945/// Return true if \p New is equal or worse than \p Old.
946static bool isEqualOrWorse(const Attribute &New, const Attribute &Old) {
947 if (!Old.isIntAttribute())
948 return true;
949
950 return Old.getValueAsInt() >= New.getValueAsInt();
951}
952
953/// Return true if the information provided by \p Attr was added to the
954/// attribute set \p AttrSet. This is only the case if it was not already
955/// present in \p AttrSet.
956static bool addIfNotExistent(LLVMContext &Ctx, const Attribute &Attr,
957 AttributeSet AttrSet, bool ForceReplace,
958 AttrBuilder &AB) {
959
960 if (Attr.isEnumAttribute()) {
961 Attribute::AttrKind Kind = Attr.getKindAsEnum();
962 if (AttrSet.hasAttribute(Kind))
963 return false;
964 AB.addAttribute(Val: Kind);
965 return true;
966 }
967 if (Attr.isStringAttribute()) {
968 StringRef Kind = Attr.getKindAsString();
969 if (AttrSet.hasAttribute(Kind)) {
970 if (!ForceReplace)
971 return false;
972 }
973 AB.addAttribute(A: Kind, V: Attr.getValueAsString());
974 return true;
975 }
976 if (Attr.isIntAttribute()) {
977 Attribute::AttrKind Kind = Attr.getKindAsEnum();
978 if (!ForceReplace && Kind == Attribute::Memory) {
979 MemoryEffects ME = Attr.getMemoryEffects() & AttrSet.getMemoryEffects();
980 if (ME == AttrSet.getMemoryEffects())
981 return false;
982 AB.addMemoryAttr(ME);
983 return true;
984 }
985 if (AttrSet.hasAttribute(Kind)) {
986 if (!ForceReplace && isEqualOrWorse(New: Attr, Old: AttrSet.getAttribute(Kind)))
987 return false;
988 }
989 AB.addAttribute(A: Attr);
990 return true;
991 }
992
993 llvm_unreachable("Expected enum or string attribute!");
994}
995
996Argument *IRPosition::getAssociatedArgument() const {
997 if (getPositionKind() == IRP_ARGUMENT)
998 return cast<Argument>(Val: &getAnchorValue());
999
1000 // Not an Argument and no argument number means this is not a call site
1001 // argument, thus we cannot find a callback argument to return.
1002 int ArgNo = getCallSiteArgNo();
1003 if (ArgNo < 0)
1004 return nullptr;
1005
1006 // Use abstract call sites to make the connection between the call site
1007 // values and the ones in callbacks. If a callback was found that makes use
1008 // of the underlying call site operand, we want the corresponding callback
1009 // callee argument and not the direct callee argument.
1010 std::optional<Argument *> CBCandidateArg;
1011 SmallVector<const Use *, 4> CallbackUses;
1012 const auto &CB = cast<CallBase>(Val&: getAnchorValue());
1013 AbstractCallSite::getCallbackUses(CB, CallbackUses);
1014 for (const Use *U : CallbackUses) {
1015 AbstractCallSite ACS(U);
1016 assert(ACS && ACS.isCallbackCall());
1017 if (!ACS.getCalledFunction())
1018 continue;
1019
1020 for (unsigned u = 0, e = ACS.getNumArgOperands(); u < e; u++) {
1021
1022 // Test if the underlying call site operand is argument number u of the
1023 // callback callee.
1024 if (ACS.getCallArgOperandNo(ArgNo: u) != ArgNo)
1025 continue;
1026
1027 assert(ACS.getCalledFunction()->arg_size() > u &&
1028 "ACS mapped into var-args arguments!");
1029 if (CBCandidateArg) {
1030 CBCandidateArg = nullptr;
1031 break;
1032 }
1033 CBCandidateArg = ACS.getCalledFunction()->getArg(i: u);
1034 }
1035 }
1036
1037 // If we found a unique callback candidate argument, return it.
1038 if (CBCandidateArg && *CBCandidateArg)
1039 return *CBCandidateArg;
1040
1041 // If no callbacks were found, or none used the underlying call site operand
1042 // exclusively, use the direct callee argument if available.
1043 auto *Callee = dyn_cast_if_present<Function>(Val: CB.getCalledOperand());
1044 if (Callee && Callee->arg_size() > unsigned(ArgNo))
1045 return Callee->getArg(i: ArgNo);
1046
1047 return nullptr;
1048}
1049
1050ChangeStatus AbstractAttribute::update(Attributor &A) {
1051 ChangeStatus HasChanged = ChangeStatus::UNCHANGED;
1052 if (getState().isAtFixpoint())
1053 return HasChanged;
1054
1055 LLVM_DEBUG(dbgs() << "[Attributor] Update: " << *this << "\n");
1056
1057 HasChanged = updateImpl(A);
1058
1059 LLVM_DEBUG(dbgs() << "[Attributor] Update " << HasChanged << " " << *this
1060 << "\n");
1061
1062 return HasChanged;
1063}
1064
1065Attributor::Attributor(SetVector<Function *> &Functions,
1066 InformationCache &InfoCache,
1067 AttributorConfig Configuration)
1068 : Allocator(InfoCache.Allocator), Functions(Functions),
1069 InfoCache(InfoCache), Configuration(Configuration) {
1070 if (!isClosedWorldModule())
1071 return;
1072 for (Function *Fn : Functions)
1073 if (Fn->hasAddressTaken(/*PutOffender=*/nullptr,
1074 /*IgnoreCallbackUses=*/false,
1075 /*IgnoreAssumeLikeCalls=*/true,
1076 /*IgnoreLLVMUsed=*/IngoreLLVMUsed: true,
1077 /*IgnoreARCAttachedCall=*/false,
1078 /*IgnoreCastedDirectCall=*/true))
1079 InfoCache.IndirectlyCallableFunctions.push_back(Elt: Fn);
1080}
1081
1082bool Attributor::getAttrsFromAssumes(const IRPosition &IRP,
1083 Attribute::AttrKind AK,
1084 SmallVectorImpl<Attribute> &Attrs) {
1085 assert(IRP.getPositionKind() != IRPosition::IRP_INVALID &&
1086 "Did expect a valid position!");
1087 MustBeExecutedContextExplorer *Explorer =
1088 getInfoCache().getMustBeExecutedContextExplorer();
1089 if (!Explorer)
1090 return false;
1091
1092 Value &AssociatedValue = IRP.getAssociatedValue();
1093
1094 const Assume2KnowledgeMap &A2K =
1095 getInfoCache().getKnowledgeMap().lookup(Val: {&AssociatedValue, AK});
1096
1097 // Check if we found any potential assume use, if not we don't need to create
1098 // explorer iterators.
1099 if (A2K.empty())
1100 return false;
1101
1102 LLVMContext &Ctx = AssociatedValue.getContext();
1103 unsigned AttrsSize = Attrs.size();
1104 auto EIt = Explorer->begin(PP: IRP.getCtxI()),
1105 EEnd = Explorer->end(IRP.getCtxI());
1106 for (const auto &It : A2K)
1107 if (Explorer->findInContextOf(I: It.first, EIt, EEnd))
1108 Attrs.push_back(Elt: Attribute::get(Context&: Ctx, Kind: AK, Val: It.second.Max));
1109 return AttrsSize != Attrs.size();
1110}
1111
1112template <typename DescTy>
1113ChangeStatus
1114Attributor::updateAttrMap(const IRPosition &IRP, ArrayRef<DescTy> AttrDescs,
1115 function_ref<bool(const DescTy &, AttributeSet,
1116 AttributeMask &, AttrBuilder &)>
1117 CB) {
1118 if (AttrDescs.empty())
1119 return ChangeStatus::UNCHANGED;
1120 switch (IRP.getPositionKind()) {
1121 case IRPosition::IRP_FLOAT:
1122 case IRPosition::IRP_INVALID:
1123 return ChangeStatus::UNCHANGED;
1124 default:
1125 break;
1126 };
1127
1128 AttributeList AL;
1129 Value *AttrListAnchor = IRP.getAttrListAnchor();
1130 auto It = AttrsMap.find(Val: AttrListAnchor);
1131 if (It == AttrsMap.end())
1132 AL = IRP.getAttrList();
1133 else
1134 AL = It->getSecond();
1135
1136 LLVMContext &Ctx = IRP.getAnchorValue().getContext();
1137 auto AttrIdx = IRP.getAttrIdx();
1138 AttributeSet AS = AL.getAttributes(Index: AttrIdx);
1139 AttributeMask AM;
1140 AttrBuilder AB(Ctx);
1141
1142 ChangeStatus HasChanged = ChangeStatus::UNCHANGED;
1143 for (const DescTy &AttrDesc : AttrDescs)
1144 if (CB(AttrDesc, AS, AM, AB))
1145 HasChanged = ChangeStatus::CHANGED;
1146
1147 if (HasChanged == ChangeStatus::UNCHANGED)
1148 return ChangeStatus::UNCHANGED;
1149
1150 AL = AL.removeAttributesAtIndex(C&: Ctx, Index: AttrIdx, AttrsToRemove: AM);
1151 AL = AL.addAttributesAtIndex(C&: Ctx, Index: AttrIdx, B: AB);
1152 AttrsMap[AttrListAnchor] = AL;
1153 return ChangeStatus::CHANGED;
1154}
1155
1156bool Attributor::hasAttr(const IRPosition &IRP,
1157 ArrayRef<Attribute::AttrKind> AttrKinds,
1158 bool IgnoreSubsumingPositions,
1159 Attribute::AttrKind ImpliedAttributeKind) {
1160 bool Implied = false;
1161 bool HasAttr = false;
1162 auto HasAttrCB = [&](const Attribute::AttrKind &Kind, AttributeSet AttrSet,
1163 AttributeMask &, AttrBuilder &) {
1164 if (AttrSet.hasAttribute(Kind)) {
1165 Implied |= Kind != ImpliedAttributeKind;
1166 HasAttr = true;
1167 }
1168 return false;
1169 };
1170 for (const IRPosition &EquivIRP : SubsumingPositionIterator(IRP)) {
1171 updateAttrMap<Attribute::AttrKind>(IRP: EquivIRP, AttrDescs: AttrKinds, CB: HasAttrCB);
1172 if (HasAttr)
1173 break;
1174 // The first position returned by the SubsumingPositionIterator is
1175 // always the position itself. If we ignore subsuming positions we
1176 // are done after the first iteration.
1177 if (IgnoreSubsumingPositions)
1178 break;
1179 Implied = true;
1180 }
1181 if (!HasAttr) {
1182 Implied = true;
1183 SmallVector<Attribute> Attrs;
1184 for (Attribute::AttrKind AK : AttrKinds)
1185 if (getAttrsFromAssumes(IRP, AK, Attrs)) {
1186 HasAttr = true;
1187 break;
1188 }
1189 }
1190
1191 // Check if we should manifest the implied attribute kind at the IRP.
1192 if (ImpliedAttributeKind != Attribute::None && HasAttr && Implied)
1193 manifestAttrs(IRP, DeducedAttrs: {Attribute::get(Context&: IRP.getAnchorValue().getContext(),
1194 Kind: ImpliedAttributeKind)});
1195 return HasAttr;
1196}
1197
1198void Attributor::getAttrs(const IRPosition &IRP,
1199 ArrayRef<Attribute::AttrKind> AttrKinds,
1200 SmallVectorImpl<Attribute> &Attrs,
1201 bool IgnoreSubsumingPositions) {
1202 auto CollectAttrCB = [&](const Attribute::AttrKind &Kind,
1203 AttributeSet AttrSet, AttributeMask &,
1204 AttrBuilder &) {
1205 if (AttrSet.hasAttribute(Kind))
1206 Attrs.push_back(Elt: AttrSet.getAttribute(Kind));
1207 return false;
1208 };
1209 for (const IRPosition &EquivIRP : SubsumingPositionIterator(IRP)) {
1210 updateAttrMap<Attribute::AttrKind>(IRP: EquivIRP, AttrDescs: AttrKinds, CB: CollectAttrCB);
1211 // The first position returned by the SubsumingPositionIterator is
1212 // always the position itself. If we ignore subsuming positions we
1213 // are done after the first iteration.
1214 if (IgnoreSubsumingPositions)
1215 break;
1216 }
1217 for (Attribute::AttrKind AK : AttrKinds)
1218 getAttrsFromAssumes(IRP, AK, Attrs);
1219}
1220
1221ChangeStatus Attributor::removeAttrs(const IRPosition &IRP,
1222 ArrayRef<Attribute::AttrKind> AttrKinds) {
1223 auto RemoveAttrCB = [&](const Attribute::AttrKind &Kind, AttributeSet AttrSet,
1224 AttributeMask &AM, AttrBuilder &) {
1225 if (!AttrSet.hasAttribute(Kind))
1226 return false;
1227 AM.addAttribute(Val: Kind);
1228 return true;
1229 };
1230 return updateAttrMap<Attribute::AttrKind>(IRP, AttrDescs: AttrKinds, CB: RemoveAttrCB);
1231}
1232
1233ChangeStatus Attributor::removeAttrs(const IRPosition &IRP,
1234 ArrayRef<StringRef> Attrs) {
1235 auto RemoveAttrCB = [&](StringRef Attr, AttributeSet AttrSet,
1236 AttributeMask &AM, AttrBuilder &) -> bool {
1237 if (!AttrSet.hasAttribute(Kind: Attr))
1238 return false;
1239 AM.addAttribute(A: Attr);
1240 return true;
1241 };
1242
1243 return updateAttrMap<StringRef>(IRP, AttrDescs: Attrs, CB: RemoveAttrCB);
1244}
1245
1246ChangeStatus Attributor::manifestAttrs(const IRPosition &IRP,
1247 ArrayRef<Attribute> Attrs,
1248 bool ForceReplace) {
1249 LLVMContext &Ctx = IRP.getAnchorValue().getContext();
1250 auto AddAttrCB = [&](const Attribute &Attr, AttributeSet AttrSet,
1251 AttributeMask &, AttrBuilder &AB) {
1252 return addIfNotExistent(Ctx, Attr, AttrSet, ForceReplace, AB);
1253 };
1254 return updateAttrMap<Attribute>(IRP, AttrDescs: Attrs, CB: AddAttrCB);
1255}
1256
1257const IRPosition IRPosition::EmptyKey(DenseMapInfo<void *>::getEmptyKey());
1258const IRPosition
1259 IRPosition::TombstoneKey(DenseMapInfo<void *>::getTombstoneKey());
1260
1261SubsumingPositionIterator::SubsumingPositionIterator(const IRPosition &IRP) {
1262 IRPositions.emplace_back(Args: IRP);
1263
1264 // Helper to determine if operand bundles on a call site are benign or
1265 // potentially problematic. We handle only llvm.assume for now.
1266 auto CanIgnoreOperandBundles = [](const CallBase &CB) {
1267 return (isa<IntrinsicInst>(CB) &&
1268 cast<IntrinsicInst>(CB).getIntrinsicID() == Intrinsic ::assume);
1269 };
1270
1271 const auto *CB = dyn_cast<CallBase>(Val: &IRP.getAnchorValue());
1272 switch (IRP.getPositionKind()) {
1273 case IRPosition::IRP_INVALID:
1274 case IRPosition::IRP_FLOAT:
1275 case IRPosition::IRP_FUNCTION:
1276 return;
1277 case IRPosition::IRP_ARGUMENT:
1278 case IRPosition::IRP_RETURNED:
1279 IRPositions.emplace_back(Args: IRPosition::function(F: *IRP.getAnchorScope()));
1280 return;
1281 case IRPosition::IRP_CALL_SITE:
1282 assert(CB && "Expected call site!");
1283 // TODO: We need to look at the operand bundles similar to the redirection
1284 // in CallBase.
1285 if (!CB->hasOperandBundles() || CanIgnoreOperandBundles(*CB))
1286 if (auto *Callee = dyn_cast_if_present<Function>(Val: CB->getCalledOperand()))
1287 IRPositions.emplace_back(Args: IRPosition::function(F: *Callee));
1288 return;
1289 case IRPosition::IRP_CALL_SITE_RETURNED:
1290 assert(CB && "Expected call site!");
1291 // TODO: We need to look at the operand bundles similar to the redirection
1292 // in CallBase.
1293 if (!CB->hasOperandBundles() || CanIgnoreOperandBundles(*CB)) {
1294 if (auto *Callee =
1295 dyn_cast_if_present<Function>(Val: CB->getCalledOperand())) {
1296 IRPositions.emplace_back(Args: IRPosition::returned(F: *Callee));
1297 IRPositions.emplace_back(Args: IRPosition::function(F: *Callee));
1298 for (const Argument &Arg : Callee->args())
1299 if (Arg.hasReturnedAttr()) {
1300 IRPositions.emplace_back(
1301 Args: IRPosition::callsite_argument(CB: *CB, ArgNo: Arg.getArgNo()));
1302 IRPositions.emplace_back(
1303 Args: IRPosition::value(V: *CB->getArgOperand(i: Arg.getArgNo())));
1304 IRPositions.emplace_back(Args: IRPosition::argument(Arg));
1305 }
1306 }
1307 }
1308 IRPositions.emplace_back(Args: IRPosition::callsite_function(CB: *CB));
1309 return;
1310 case IRPosition::IRP_CALL_SITE_ARGUMENT: {
1311 assert(CB && "Expected call site!");
1312 // TODO: We need to look at the operand bundles similar to the redirection
1313 // in CallBase.
1314 if (!CB->hasOperandBundles() || CanIgnoreOperandBundles(*CB)) {
1315 auto *Callee = dyn_cast_if_present<Function>(Val: CB->getCalledOperand());
1316 if (Callee) {
1317 if (Argument *Arg = IRP.getAssociatedArgument())
1318 IRPositions.emplace_back(Args: IRPosition::argument(Arg: *Arg));
1319 IRPositions.emplace_back(Args: IRPosition::function(F: *Callee));
1320 }
1321 }
1322 IRPositions.emplace_back(Args: IRPosition::value(V: IRP.getAssociatedValue()));
1323 return;
1324 }
1325 }
1326}
1327
1328void IRPosition::verify() {
1329#ifdef EXPENSIVE_CHECKS
1330 switch (getPositionKind()) {
1331 case IRP_INVALID:
1332 assert((CBContext == nullptr) &&
1333 "Invalid position must not have CallBaseContext!");
1334 assert(!Enc.getOpaqueValue() &&
1335 "Expected a nullptr for an invalid position!");
1336 return;
1337 case IRP_FLOAT:
1338 assert((!isa<Argument>(&getAssociatedValue())) &&
1339 "Expected specialized kind for argument values!");
1340 return;
1341 case IRP_RETURNED:
1342 assert(isa<Function>(getAsValuePtr()) &&
1343 "Expected function for a 'returned' position!");
1344 assert(getAsValuePtr() == &getAssociatedValue() &&
1345 "Associated value mismatch!");
1346 return;
1347 case IRP_CALL_SITE_RETURNED:
1348 assert((CBContext == nullptr) &&
1349 "'call site returned' position must not have CallBaseContext!");
1350 assert((isa<CallBase>(getAsValuePtr())) &&
1351 "Expected call base for 'call site returned' position!");
1352 assert(getAsValuePtr() == &getAssociatedValue() &&
1353 "Associated value mismatch!");
1354 return;
1355 case IRP_CALL_SITE:
1356 assert((CBContext == nullptr) &&
1357 "'call site function' position must not have CallBaseContext!");
1358 assert((isa<CallBase>(getAsValuePtr())) &&
1359 "Expected call base for 'call site function' position!");
1360 assert(getAsValuePtr() == &getAssociatedValue() &&
1361 "Associated value mismatch!");
1362 return;
1363 case IRP_FUNCTION:
1364 assert(isa<Function>(getAsValuePtr()) &&
1365 "Expected function for a 'function' position!");
1366 assert(getAsValuePtr() == &getAssociatedValue() &&
1367 "Associated value mismatch!");
1368 return;
1369 case IRP_ARGUMENT:
1370 assert(isa<Argument>(getAsValuePtr()) &&
1371 "Expected argument for a 'argument' position!");
1372 assert(getAsValuePtr() == &getAssociatedValue() &&
1373 "Associated value mismatch!");
1374 return;
1375 case IRP_CALL_SITE_ARGUMENT: {
1376 assert((CBContext == nullptr) &&
1377 "'call site argument' position must not have CallBaseContext!");
1378 Use *U = getAsUsePtr();
1379 (void)U; // Silence unused variable warning.
1380 assert(U && "Expected use for a 'call site argument' position!");
1381 assert(isa<CallBase>(U->getUser()) &&
1382 "Expected call base user for a 'call site argument' position!");
1383 assert(cast<CallBase>(U->getUser())->isArgOperand(U) &&
1384 "Expected call base argument operand for a 'call site argument' "
1385 "position");
1386 assert(cast<CallBase>(U->getUser())->getArgOperandNo(U) ==
1387 unsigned(getCallSiteArgNo()) &&
1388 "Argument number mismatch!");
1389 assert(U->get() == &getAssociatedValue() && "Associated value mismatch!");
1390 return;
1391 }
1392 }
1393#endif
1394}
1395
1396std::optional<Constant *>
1397Attributor::getAssumedConstant(const IRPosition &IRP,
1398 const AbstractAttribute &AA,
1399 bool &UsedAssumedInformation) {
1400 // First check all callbacks provided by outside AAs. If any of them returns
1401 // a non-null value that is different from the associated value, or
1402 // std::nullopt, we assume it's simplified.
1403 for (auto &CB : SimplificationCallbacks.lookup(Val: IRP)) {
1404 std::optional<Value *> SimplifiedV = CB(IRP, &AA, UsedAssumedInformation);
1405 if (!SimplifiedV)
1406 return std::nullopt;
1407 if (isa_and_nonnull<Constant>(Val: *SimplifiedV))
1408 return cast<Constant>(Val: *SimplifiedV);
1409 return nullptr;
1410 }
1411 if (auto *C = dyn_cast<Constant>(Val: &IRP.getAssociatedValue()))
1412 return C;
1413 SmallVector<AA::ValueAndContext> Values;
1414 if (getAssumedSimplifiedValues(IRP, AA: &AA, Values,
1415 S: AA::ValueScope::Interprocedural,
1416 UsedAssumedInformation)) {
1417 if (Values.empty())
1418 return std::nullopt;
1419 if (auto *C = dyn_cast_or_null<Constant>(
1420 Val: AAPotentialValues::getSingleValue(A&: *this, AA, IRP, Values)))
1421 return C;
1422 }
1423 return nullptr;
1424}
1425
1426std::optional<Value *> Attributor::getAssumedSimplified(
1427 const IRPosition &IRP, const AbstractAttribute *AA,
1428 bool &UsedAssumedInformation, AA::ValueScope S) {
1429 // First check all callbacks provided by outside AAs. If any of them returns
1430 // a non-null value that is different from the associated value, or
1431 // std::nullopt, we assume it's simplified.
1432 for (auto &CB : SimplificationCallbacks.lookup(Val: IRP))
1433 return CB(IRP, AA, UsedAssumedInformation);
1434
1435 SmallVector<AA::ValueAndContext> Values;
1436 if (!getAssumedSimplifiedValues(IRP, AA, Values, S, UsedAssumedInformation))
1437 return &IRP.getAssociatedValue();
1438 if (Values.empty())
1439 return std::nullopt;
1440 if (AA)
1441 if (Value *V = AAPotentialValues::getSingleValue(A&: *this, AA: *AA, IRP, Values))
1442 return V;
1443 if (IRP.getPositionKind() == IRPosition::IRP_RETURNED ||
1444 IRP.getPositionKind() == IRPosition::IRP_CALL_SITE_RETURNED)
1445 return nullptr;
1446 return &IRP.getAssociatedValue();
1447}
1448
1449bool Attributor::getAssumedSimplifiedValues(
1450 const IRPosition &InitialIRP, const AbstractAttribute *AA,
1451 SmallVectorImpl<AA::ValueAndContext> &Values, AA::ValueScope S,
1452 bool &UsedAssumedInformation, bool RecurseForSelectAndPHI) {
1453 SmallPtrSet<Value *, 8> Seen;
1454 SmallVector<IRPosition, 8> Worklist;
1455 Worklist.push_back(Elt: InitialIRP);
1456 while (!Worklist.empty()) {
1457 const IRPosition &IRP = Worklist.pop_back_val();
1458
1459 // First check all callbacks provided by outside AAs. If any of them returns
1460 // a non-null value that is different from the associated value, or
1461 // std::nullopt, we assume it's simplified.
1462 int NV = Values.size();
1463 const auto &SimplificationCBs = SimplificationCallbacks.lookup(Val: IRP);
1464 for (const auto &CB : SimplificationCBs) {
1465 std::optional<Value *> CBResult = CB(IRP, AA, UsedAssumedInformation);
1466 if (!CBResult.has_value())
1467 continue;
1468 Value *V = *CBResult;
1469 if (!V)
1470 return false;
1471 if ((S & AA::ValueScope::Interprocedural) ||
1472 AA::isValidInScope(V: *V, Scope: IRP.getAnchorScope()))
1473 Values.push_back(Elt: AA::ValueAndContext{*V, nullptr});
1474 else
1475 return false;
1476 }
1477 if (SimplificationCBs.empty()) {
1478 // If no high-level/outside simplification occurred, use
1479 // AAPotentialValues.
1480 const auto *PotentialValuesAA =
1481 getOrCreateAAFor<AAPotentialValues>(IRP, QueryingAA: AA, DepClass: DepClassTy::OPTIONAL);
1482 if (PotentialValuesAA && PotentialValuesAA->getAssumedSimplifiedValues(A&: *this, Values, S)) {
1483 UsedAssumedInformation |= !PotentialValuesAA->isAtFixpoint();
1484 } else if (IRP.getPositionKind() != IRPosition::IRP_RETURNED) {
1485 Values.push_back(Elt: {IRP.getAssociatedValue(), IRP.getCtxI()});
1486 } else {
1487 // TODO: We could visit all returns and add the operands.
1488 return false;
1489 }
1490 }
1491
1492 if (!RecurseForSelectAndPHI)
1493 break;
1494
1495 for (int I = NV, E = Values.size(); I < E; ++I) {
1496 Value *V = Values[I].getValue();
1497 if (!isa<PHINode>(Val: V) && !isa<SelectInst>(Val: V))
1498 continue;
1499 if (!Seen.insert(Ptr: V).second)
1500 continue;
1501 // Move the last element to this slot.
1502 Values[I] = Values[E - 1];
1503 // Eliminate the last slot, adjust the indices.
1504 Values.pop_back();
1505 --E;
1506 --I;
1507 // Add a new value (select or phi) to the worklist.
1508 Worklist.push_back(Elt: IRPosition::value(V: *V));
1509 }
1510 }
1511 return true;
1512}
1513
1514std::optional<Value *> Attributor::translateArgumentToCallSiteContent(
1515 std::optional<Value *> V, CallBase &CB, const AbstractAttribute &AA,
1516 bool &UsedAssumedInformation) {
1517 if (!V)
1518 return V;
1519 if (*V == nullptr || isa<Constant>(Val: *V))
1520 return V;
1521 if (auto *Arg = dyn_cast<Argument>(Val: *V))
1522 if (CB.getCalledOperand() == Arg->getParent() &&
1523 CB.arg_size() > Arg->getArgNo())
1524 if (!Arg->hasPointeeInMemoryValueAttr())
1525 return getAssumedSimplified(
1526 IRP: IRPosition::callsite_argument(CB, ArgNo: Arg->getArgNo()), AA,
1527 UsedAssumedInformation, S: AA::Intraprocedural);
1528 return nullptr;
1529}
1530
1531Attributor::~Attributor() {
1532 // The abstract attributes are allocated via the BumpPtrAllocator Allocator,
1533 // thus we cannot delete them. We can, and want to, destruct them though.
1534 for (auto &It : AAMap) {
1535 AbstractAttribute *AA = It.getSecond();
1536 AA->~AbstractAttribute();
1537 }
1538}
1539
1540bool Attributor::isAssumedDead(const AbstractAttribute &AA,
1541 const AAIsDead *FnLivenessAA,
1542 bool &UsedAssumedInformation,
1543 bool CheckBBLivenessOnly, DepClassTy DepClass) {
1544 if (!Configuration.UseLiveness)
1545 return false;
1546 const IRPosition &IRP = AA.getIRPosition();
1547 if (!Functions.count(key: IRP.getAnchorScope()))
1548 return false;
1549 return isAssumedDead(IRP, QueryingAA: &AA, FnLivenessAA, UsedAssumedInformation,
1550 CheckBBLivenessOnly, DepClass);
1551}
1552
1553bool Attributor::isAssumedDead(const Use &U,
1554 const AbstractAttribute *QueryingAA,
1555 const AAIsDead *FnLivenessAA,
1556 bool &UsedAssumedInformation,
1557 bool CheckBBLivenessOnly, DepClassTy DepClass) {
1558 if (!Configuration.UseLiveness)
1559 return false;
1560 Instruction *UserI = dyn_cast<Instruction>(Val: U.getUser());
1561 if (!UserI)
1562 return isAssumedDead(IRP: IRPosition::value(V: *U.get()), QueryingAA, FnLivenessAA,
1563 UsedAssumedInformation, CheckBBLivenessOnly, DepClass);
1564
1565 if (auto *CB = dyn_cast<CallBase>(Val: UserI)) {
1566 // For call site argument uses we can check if the argument is
1567 // unused/dead.
1568 if (CB->isArgOperand(U: &U)) {
1569 const IRPosition &CSArgPos =
1570 IRPosition::callsite_argument(CB: *CB, ArgNo: CB->getArgOperandNo(U: &U));
1571 return isAssumedDead(IRP: CSArgPos, QueryingAA, FnLivenessAA,
1572 UsedAssumedInformation, CheckBBLivenessOnly,
1573 DepClass);
1574 }
1575 } else if (ReturnInst *RI = dyn_cast<ReturnInst>(Val: UserI)) {
1576 const IRPosition &RetPos = IRPosition::returned(F: *RI->getFunction());
1577 return isAssumedDead(IRP: RetPos, QueryingAA, FnLivenessAA,
1578 UsedAssumedInformation, CheckBBLivenessOnly, DepClass);
1579 } else if (PHINode *PHI = dyn_cast<PHINode>(Val: UserI)) {
1580 BasicBlock *IncomingBB = PHI->getIncomingBlock(U);
1581 return isAssumedDead(I: *IncomingBB->getTerminator(), QueryingAA, LivenessAA: FnLivenessAA,
1582 UsedAssumedInformation, CheckBBLivenessOnly, DepClass);
1583 } else if (StoreInst *SI = dyn_cast<StoreInst>(Val: UserI)) {
1584 if (!CheckBBLivenessOnly && SI->getPointerOperand() != U.get()) {
1585 const IRPosition IRP = IRPosition::inst(I: *SI);
1586 const AAIsDead *IsDeadAA =
1587 getOrCreateAAFor<AAIsDead>(IRP, QueryingAA, DepClass: DepClassTy::NONE);
1588 if (IsDeadAA && IsDeadAA->isRemovableStore()) {
1589 if (QueryingAA)
1590 recordDependence(FromAA: *IsDeadAA, ToAA: *QueryingAA, DepClass);
1591 if (!IsDeadAA->isKnown(BitsEncoding: AAIsDead::IS_REMOVABLE))
1592 UsedAssumedInformation = true;
1593 return true;
1594 }
1595 }
1596 }
1597
1598 return isAssumedDead(IRP: IRPosition::inst(I: *UserI), QueryingAA, FnLivenessAA,
1599 UsedAssumedInformation, CheckBBLivenessOnly, DepClass);
1600}
1601
1602bool Attributor::isAssumedDead(const Instruction &I,
1603 const AbstractAttribute *QueryingAA,
1604 const AAIsDead *FnLivenessAA,
1605 bool &UsedAssumedInformation,
1606 bool CheckBBLivenessOnly, DepClassTy DepClass,
1607 bool CheckForDeadStore) {
1608 if (!Configuration.UseLiveness)
1609 return false;
1610 const IRPosition::CallBaseContext *CBCtx =
1611 QueryingAA ? QueryingAA->getCallBaseContext() : nullptr;
1612
1613 if (ManifestAddedBlocks.contains(Ptr: I.getParent()))
1614 return false;
1615
1616 const Function &F = *I.getFunction();
1617 if (!FnLivenessAA || FnLivenessAA->getAnchorScope() != &F)
1618 FnLivenessAA = getOrCreateAAFor<AAIsDead>(IRP: IRPosition::function(F, CBContext: CBCtx),
1619 QueryingAA, DepClass: DepClassTy::NONE);
1620
1621 // Don't use recursive reasoning.
1622 if (!FnLivenessAA || QueryingAA == FnLivenessAA)
1623 return false;
1624
1625 // If we have a context instruction and a liveness AA we use it.
1626 if (CheckBBLivenessOnly ? FnLivenessAA->isAssumedDead(BB: I.getParent())
1627 : FnLivenessAA->isAssumedDead(I: &I)) {
1628 if (QueryingAA)
1629 recordDependence(FromAA: *FnLivenessAA, ToAA: *QueryingAA, DepClass);
1630 if (!FnLivenessAA->isKnownDead(I: &I))
1631 UsedAssumedInformation = true;
1632 return true;
1633 }
1634
1635 if (CheckBBLivenessOnly)
1636 return false;
1637
1638 const IRPosition IRP = IRPosition::inst(I, CBContext: CBCtx);
1639 const AAIsDead *IsDeadAA =
1640 getOrCreateAAFor<AAIsDead>(IRP, QueryingAA, DepClass: DepClassTy::NONE);
1641
1642 // Don't use recursive reasoning.
1643 if (!IsDeadAA || QueryingAA == IsDeadAA)
1644 return false;
1645
1646 if (IsDeadAA->isAssumedDead()) {
1647 if (QueryingAA)
1648 recordDependence(FromAA: *IsDeadAA, ToAA: *QueryingAA, DepClass);
1649 if (!IsDeadAA->isKnownDead())
1650 UsedAssumedInformation = true;
1651 return true;
1652 }
1653
1654 if (CheckForDeadStore && isa<StoreInst>(Val: I) && IsDeadAA->isRemovableStore()) {
1655 if (QueryingAA)
1656 recordDependence(FromAA: *IsDeadAA, ToAA: *QueryingAA, DepClass);
1657 if (!IsDeadAA->isKnownDead())
1658 UsedAssumedInformation = true;
1659 return true;
1660 }
1661
1662 return false;
1663}
1664
1665bool Attributor::isAssumedDead(const IRPosition &IRP,
1666 const AbstractAttribute *QueryingAA,
1667 const AAIsDead *FnLivenessAA,
1668 bool &UsedAssumedInformation,
1669 bool CheckBBLivenessOnly, DepClassTy DepClass) {
1670 if (!Configuration.UseLiveness)
1671 return false;
1672 // Don't check liveness for constants, e.g. functions, used as (floating)
1673 // values since the context instruction and such is here meaningless.
1674 if (IRP.getPositionKind() == IRPosition::IRP_FLOAT &&
1675 isa<Constant>(Val: IRP.getAssociatedValue())) {
1676 return false;
1677 }
1678
1679 Instruction *CtxI = IRP.getCtxI();
1680 if (CtxI &&
1681 isAssumedDead(I: *CtxI, QueryingAA, FnLivenessAA, UsedAssumedInformation,
1682 /* CheckBBLivenessOnly */ true,
1683 DepClass: CheckBBLivenessOnly ? DepClass : DepClassTy::OPTIONAL))
1684 return true;
1685
1686 if (CheckBBLivenessOnly)
1687 return false;
1688
1689 // If we haven't succeeded we query the specific liveness info for the IRP.
1690 const AAIsDead *IsDeadAA;
1691 if (IRP.getPositionKind() == IRPosition::IRP_CALL_SITE)
1692 IsDeadAA = getOrCreateAAFor<AAIsDead>(
1693 IRP: IRPosition::callsite_returned(CB: cast<CallBase>(Val&: IRP.getAssociatedValue())),
1694 QueryingAA, DepClass: DepClassTy::NONE);
1695 else
1696 IsDeadAA = getOrCreateAAFor<AAIsDead>(IRP, QueryingAA, DepClass: DepClassTy::NONE);
1697
1698 // Don't use recursive reasoning.
1699 if (!IsDeadAA || QueryingAA == IsDeadAA)
1700 return false;
1701
1702 if (IsDeadAA->isAssumedDead()) {
1703 if (QueryingAA)
1704 recordDependence(FromAA: *IsDeadAA, ToAA: *QueryingAA, DepClass);
1705 if (!IsDeadAA->isKnownDead())
1706 UsedAssumedInformation = true;
1707 return true;
1708 }
1709
1710 return false;
1711}
1712
1713bool Attributor::isAssumedDead(const BasicBlock &BB,
1714 const AbstractAttribute *QueryingAA,
1715 const AAIsDead *FnLivenessAA,
1716 DepClassTy DepClass) {
1717 if (!Configuration.UseLiveness)
1718 return false;
1719 const Function &F = *BB.getParent();
1720 if (!FnLivenessAA || FnLivenessAA->getAnchorScope() != &F)
1721 FnLivenessAA = getOrCreateAAFor<AAIsDead>(IRP: IRPosition::function(F),
1722 QueryingAA, DepClass: DepClassTy::NONE);
1723
1724 // Don't use recursive reasoning.
1725 if (!FnLivenessAA || QueryingAA == FnLivenessAA)
1726 return false;
1727
1728 if (FnLivenessAA->isAssumedDead(BB: &BB)) {
1729 if (QueryingAA)
1730 recordDependence(FromAA: *FnLivenessAA, ToAA: *QueryingAA, DepClass);
1731 return true;
1732 }
1733
1734 return false;
1735}
1736
1737bool Attributor::checkForAllCallees(
1738 function_ref<bool(ArrayRef<const Function *>)> Pred,
1739 const AbstractAttribute &QueryingAA, const CallBase &CB) {
1740 if (const Function *Callee = dyn_cast<Function>(Val: CB.getCalledOperand()))
1741 return Pred(Callee);
1742
1743 const auto *CallEdgesAA = getAAFor<AACallEdges>(
1744 QueryingAA, IRP: IRPosition::callsite_function(CB), DepClass: DepClassTy::OPTIONAL);
1745 if (!CallEdgesAA || CallEdgesAA->hasUnknownCallee())
1746 return false;
1747
1748 const auto &Callees = CallEdgesAA->getOptimisticEdges();
1749 return Pred(Callees.getArrayRef());
1750}
1751
1752bool Attributor::checkForAllUses(
1753 function_ref<bool(const Use &, bool &)> Pred,
1754 const AbstractAttribute &QueryingAA, const Value &V,
1755 bool CheckBBLivenessOnly, DepClassTy LivenessDepClass,
1756 bool IgnoreDroppableUses,
1757 function_ref<bool(const Use &OldU, const Use &NewU)> EquivalentUseCB) {
1758
1759 // Check virtual uses first.
1760 for (VirtualUseCallbackTy &CB : VirtualUseCallbacks.lookup(Val: &V))
1761 if (!CB(*this, &QueryingAA))
1762 return false;
1763
1764 // Check the trivial case first as it catches void values.
1765 if (V.use_empty())
1766 return true;
1767
1768 const IRPosition &IRP = QueryingAA.getIRPosition();
1769 SmallVector<const Use *, 16> Worklist;
1770 SmallPtrSet<const Use *, 16> Visited;
1771
1772 auto AddUsers = [&](const Value &V, const Use *OldUse) {
1773 for (const Use &UU : V.uses()) {
1774 if (OldUse && EquivalentUseCB && !EquivalentUseCB(*OldUse, UU)) {
1775 LLVM_DEBUG(dbgs() << "[Attributor] Potential copy was "
1776 "rejected by the equivalence call back: "
1777 << *UU << "!\n");
1778 return false;
1779 }
1780
1781 Worklist.push_back(Elt: &UU);
1782 }
1783 return true;
1784 };
1785
1786 AddUsers(V, /* OldUse */ nullptr);
1787
1788 LLVM_DEBUG(dbgs() << "[Attributor] Got " << Worklist.size()
1789 << " initial uses to check\n");
1790
1791 const Function *ScopeFn = IRP.getAnchorScope();
1792 const auto *LivenessAA =
1793 ScopeFn ? getAAFor<AAIsDead>(QueryingAA, IRP: IRPosition::function(F: *ScopeFn),
1794 DepClass: DepClassTy::NONE)
1795 : nullptr;
1796
1797 while (!Worklist.empty()) {
1798 const Use *U = Worklist.pop_back_val();
1799 if (isa<PHINode>(Val: U->getUser()) && !Visited.insert(Ptr: U).second)
1800 continue;
1801 DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE, {
1802 if (auto *Fn = dyn_cast<Function>(U->getUser()))
1803 dbgs() << "[Attributor] Check use: " << **U << " in " << Fn->getName()
1804 << "\n";
1805 else
1806 dbgs() << "[Attributor] Check use: " << **U << " in " << *U->getUser()
1807 << "\n";
1808 });
1809 bool UsedAssumedInformation = false;
1810 if (isAssumedDead(U: *U, QueryingAA: &QueryingAA, FnLivenessAA: LivenessAA, UsedAssumedInformation,
1811 CheckBBLivenessOnly, DepClass: LivenessDepClass)) {
1812 DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE,
1813 dbgs() << "[Attributor] Dead use, skip!\n");
1814 continue;
1815 }
1816 if (IgnoreDroppableUses && U->getUser()->isDroppable()) {
1817 DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE,
1818 dbgs() << "[Attributor] Droppable user, skip!\n");
1819 continue;
1820 }
1821
1822 if (auto *SI = dyn_cast<StoreInst>(Val: U->getUser())) {
1823 if (&SI->getOperandUse(i: 0) == U) {
1824 if (!Visited.insert(Ptr: U).second)
1825 continue;
1826 SmallSetVector<Value *, 4> PotentialCopies;
1827 if (AA::getPotentialCopiesOfStoredValue(
1828 A&: *this, SI&: *SI, PotentialCopies, QueryingAA, UsedAssumedInformation,
1829 /* OnlyExact */ true)) {
1830 DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE,
1831 dbgs()
1832 << "[Attributor] Value is stored, continue with "
1833 << PotentialCopies.size()
1834 << " potential copies instead!\n");
1835 for (Value *PotentialCopy : PotentialCopies)
1836 if (!AddUsers(*PotentialCopy, U))
1837 return false;
1838 continue;
1839 }
1840 }
1841 }
1842
1843 bool Follow = false;
1844 if (!Pred(*U, Follow))
1845 return false;
1846 if (!Follow)
1847 continue;
1848
1849 User &Usr = *U->getUser();
1850 AddUsers(Usr, /* OldUse */ nullptr);
1851
1852 auto *RI = dyn_cast<ReturnInst>(Val: &Usr);
1853 if (!RI)
1854 continue;
1855
1856 Function &F = *RI->getFunction();
1857 auto CallSitePred = [&](AbstractCallSite ACS) {
1858 return AddUsers(*ACS.getInstruction(), U);
1859 };
1860 if (!checkForAllCallSites(Pred: CallSitePred, Fn: F, /* RequireAllCallSites */ true,
1861 QueryingAA: &QueryingAA, UsedAssumedInformation)) {
1862 LLVM_DEBUG(dbgs() << "[Attributor] Could not follow return instruction "
1863 "to all call sites: "
1864 << *RI << "\n");
1865 return false;
1866 }
1867 }
1868
1869 return true;
1870}
1871
1872bool Attributor::checkForAllCallSites(function_ref<bool(AbstractCallSite)> Pred,
1873 const AbstractAttribute &QueryingAA,
1874 bool RequireAllCallSites,
1875 bool &UsedAssumedInformation) {
1876 // We can try to determine information from
1877 // the call sites. However, this is only possible all call sites are known,
1878 // hence the function has internal linkage.
1879 const IRPosition &IRP = QueryingAA.getIRPosition();
1880 const Function *AssociatedFunction = IRP.getAssociatedFunction();
1881 if (!AssociatedFunction) {
1882 LLVM_DEBUG(dbgs() << "[Attributor] No function associated with " << IRP
1883 << "\n");
1884 return false;
1885 }
1886
1887 return checkForAllCallSites(Pred, Fn: *AssociatedFunction, RequireAllCallSites,
1888 QueryingAA: &QueryingAA, UsedAssumedInformation);
1889}
1890
1891bool Attributor::checkForAllCallSites(function_ref<bool(AbstractCallSite)> Pred,
1892 const Function &Fn,
1893 bool RequireAllCallSites,
1894 const AbstractAttribute *QueryingAA,
1895 bool &UsedAssumedInformation,
1896 bool CheckPotentiallyDead) {
1897 if (RequireAllCallSites && !Fn.hasLocalLinkage()) {
1898 LLVM_DEBUG(
1899 dbgs()
1900 << "[Attributor] Function " << Fn.getName()
1901 << " has no internal linkage, hence not all call sites are known\n");
1902 return false;
1903 }
1904 // Check virtual uses first.
1905 for (VirtualUseCallbackTy &CB : VirtualUseCallbacks.lookup(Val: &Fn))
1906 if (!CB(*this, QueryingAA))
1907 return false;
1908
1909 SmallVector<const Use *, 8> Uses(make_pointer_range(Range: Fn.uses()));
1910 for (unsigned u = 0; u < Uses.size(); ++u) {
1911 const Use &U = *Uses[u];
1912 DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE, {
1913 if (auto *Fn = dyn_cast<Function>(U))
1914 dbgs() << "[Attributor] Check use: " << Fn->getName() << " in "
1915 << *U.getUser() << "\n";
1916 else
1917 dbgs() << "[Attributor] Check use: " << *U << " in " << *U.getUser()
1918 << "\n";
1919 });
1920 if (!CheckPotentiallyDead &&
1921 isAssumedDead(U, QueryingAA, FnLivenessAA: nullptr, UsedAssumedInformation,
1922 /* CheckBBLivenessOnly */ true)) {
1923 DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE,
1924 dbgs() << "[Attributor] Dead use, skip!\n");
1925 continue;
1926 }
1927 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Val: U.getUser())) {
1928 if (CE->isCast() && CE->getType()->isPointerTy()) {
1929 DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE, {
1930 dbgs() << "[Attributor] Use, is constant cast expression, add "
1931 << CE->getNumUses() << " uses of that expression instead!\n";
1932 });
1933 for (const Use &CEU : CE->uses())
1934 Uses.push_back(Elt: &CEU);
1935 continue;
1936 }
1937 }
1938
1939 AbstractCallSite ACS(&U);
1940 if (!ACS) {
1941 LLVM_DEBUG(dbgs() << "[Attributor] Function " << Fn.getName()
1942 << " has non call site use " << *U.get() << " in "
1943 << *U.getUser() << "\n");
1944 // BlockAddress users are allowed.
1945 if (isa<BlockAddress>(Val: U.getUser()))
1946 continue;
1947 return false;
1948 }
1949
1950 const Use *EffectiveUse =
1951 ACS.isCallbackCall() ? &ACS.getCalleeUseForCallback() : &U;
1952 if (!ACS.isCallee(U: EffectiveUse)) {
1953 if (!RequireAllCallSites) {
1954 LLVM_DEBUG(dbgs() << "[Attributor] User " << *EffectiveUse->getUser()
1955 << " is not a call of " << Fn.getName()
1956 << ", skip use\n");
1957 continue;
1958 }
1959 LLVM_DEBUG(dbgs() << "[Attributor] User " << *EffectiveUse->getUser()
1960 << " is an invalid use of " << Fn.getName() << "\n");
1961 return false;
1962 }
1963
1964 // Make sure the arguments that can be matched between the call site and the
1965 // callee argee on their type. It is unlikely they do not and it doesn't
1966 // make sense for all attributes to know/care about this.
1967 assert(&Fn == ACS.getCalledFunction() && "Expected known callee");
1968 unsigned MinArgsParams =
1969 std::min(a: size_t(ACS.getNumArgOperands()), b: Fn.arg_size());
1970 for (unsigned u = 0; u < MinArgsParams; ++u) {
1971 Value *CSArgOp = ACS.getCallArgOperand(ArgNo: u);
1972 if (CSArgOp && Fn.getArg(i: u)->getType() != CSArgOp->getType()) {
1973 LLVM_DEBUG(
1974 dbgs() << "[Attributor] Call site / callee argument type mismatch ["
1975 << u << "@" << Fn.getName() << ": "
1976 << *Fn.getArg(u)->getType() << " vs. "
1977 << *ACS.getCallArgOperand(u)->getType() << "\n");
1978 return false;
1979 }
1980 }
1981
1982 if (Pred(ACS))
1983 continue;
1984
1985 LLVM_DEBUG(dbgs() << "[Attributor] Call site callback failed for "
1986 << *ACS.getInstruction() << "\n");
1987 return false;
1988 }
1989
1990 return true;
1991}
1992
1993bool Attributor::shouldPropagateCallBaseContext(const IRPosition &IRP) {
1994 // TODO: Maintain a cache of Values that are
1995 // on the pathway from a Argument to a Instruction that would effect the
1996 // liveness/return state etc.
1997 return EnableCallSiteSpecific;
1998}
1999
2000bool Attributor::checkForAllReturnedValues(function_ref<bool(Value &)> Pred,
2001 const AbstractAttribute &QueryingAA,
2002 AA::ValueScope S,
2003 bool RecurseForSelectAndPHI) {
2004
2005 const IRPosition &IRP = QueryingAA.getIRPosition();
2006 const Function *AssociatedFunction = IRP.getAssociatedFunction();
2007 if (!AssociatedFunction)
2008 return false;
2009
2010 bool UsedAssumedInformation = false;
2011 SmallVector<AA::ValueAndContext> Values;
2012 if (!getAssumedSimplifiedValues(
2013 InitialIRP: IRPosition::returned(F: *AssociatedFunction), AA: &QueryingAA, Values, S,
2014 UsedAssumedInformation, RecurseForSelectAndPHI))
2015 return false;
2016
2017 return llvm::all_of(Range&: Values, P: [&](const AA::ValueAndContext &VAC) {
2018 return Pred(*VAC.getValue());
2019 });
2020}
2021
2022static bool checkForAllInstructionsImpl(
2023 Attributor *A, InformationCache::OpcodeInstMapTy &OpcodeInstMap,
2024 function_ref<bool(Instruction &)> Pred, const AbstractAttribute *QueryingAA,
2025 const AAIsDead *LivenessAA, ArrayRef<unsigned> Opcodes,
2026 bool &UsedAssumedInformation, bool CheckBBLivenessOnly = false,
2027 bool CheckPotentiallyDead = false) {
2028 for (unsigned Opcode : Opcodes) {
2029 // Check if we have instructions with this opcode at all first.
2030 auto *Insts = OpcodeInstMap.lookup(Val: Opcode);
2031 if (!Insts)
2032 continue;
2033
2034 for (Instruction *I : *Insts) {
2035 // Skip dead instructions.
2036 if (A && !CheckPotentiallyDead &&
2037 A->isAssumedDead(IRP: IRPosition::inst(I: *I), QueryingAA, FnLivenessAA: LivenessAA,
2038 UsedAssumedInformation, CheckBBLivenessOnly)) {
2039 DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE,
2040 dbgs() << "[Attributor] Instruction " << *I
2041 << " is potentially dead, skip!\n";);
2042 continue;
2043 }
2044
2045 if (!Pred(*I))
2046 return false;
2047 }
2048 }
2049 return true;
2050}
2051
2052bool Attributor::checkForAllInstructions(function_ref<bool(Instruction &)> Pred,
2053 const Function *Fn,
2054 const AbstractAttribute *QueryingAA,
2055 ArrayRef<unsigned> Opcodes,
2056 bool &UsedAssumedInformation,
2057 bool CheckBBLivenessOnly,
2058 bool CheckPotentiallyDead) {
2059 // Since we need to provide instructions we have to have an exact definition.
2060 if (!Fn || Fn->isDeclaration())
2061 return false;
2062
2063 const IRPosition &QueryIRP = IRPosition::function(F: *Fn);
2064 const auto *LivenessAA =
2065 CheckPotentiallyDead && QueryingAA
2066 ? (getAAFor<AAIsDead>(QueryingAA: *QueryingAA, IRP: QueryIRP, DepClass: DepClassTy::NONE))
2067 : nullptr;
2068
2069 auto &OpcodeInstMap = InfoCache.getOpcodeInstMapForFunction(F: *Fn);
2070 if (!checkForAllInstructionsImpl(A: this, OpcodeInstMap, Pred, QueryingAA,
2071 LivenessAA, Opcodes, UsedAssumedInformation,
2072 CheckBBLivenessOnly, CheckPotentiallyDead))
2073 return false;
2074
2075 return true;
2076}
2077
2078bool Attributor::checkForAllInstructions(function_ref<bool(Instruction &)> Pred,
2079 const AbstractAttribute &QueryingAA,
2080 ArrayRef<unsigned> Opcodes,
2081 bool &UsedAssumedInformation,
2082 bool CheckBBLivenessOnly,
2083 bool CheckPotentiallyDead) {
2084 const IRPosition &IRP = QueryingAA.getIRPosition();
2085 const Function *AssociatedFunction = IRP.getAssociatedFunction();
2086 return checkForAllInstructions(Pred, Fn: AssociatedFunction, QueryingAA: &QueryingAA, Opcodes,
2087 UsedAssumedInformation, CheckBBLivenessOnly,
2088 CheckPotentiallyDead);
2089}
2090
2091bool Attributor::checkForAllReadWriteInstructions(
2092 function_ref<bool(Instruction &)> Pred, AbstractAttribute &QueryingAA,
2093 bool &UsedAssumedInformation) {
2094 TimeTraceScope TS("checkForAllReadWriteInstructions");
2095
2096 const Function *AssociatedFunction =
2097 QueryingAA.getIRPosition().getAssociatedFunction();
2098 if (!AssociatedFunction)
2099 return false;
2100
2101 const IRPosition &QueryIRP = IRPosition::function(F: *AssociatedFunction);
2102 const auto *LivenessAA =
2103 getAAFor<AAIsDead>(QueryingAA, IRP: QueryIRP, DepClass: DepClassTy::NONE);
2104
2105 for (Instruction *I :
2106 InfoCache.getReadOrWriteInstsForFunction(F: *AssociatedFunction)) {
2107 // Skip dead instructions.
2108 if (isAssumedDead(IRP: IRPosition::inst(I: *I), QueryingAA: &QueryingAA, FnLivenessAA: LivenessAA,
2109 UsedAssumedInformation))
2110 continue;
2111
2112 if (!Pred(*I))
2113 return false;
2114 }
2115
2116 return true;
2117}
2118
2119void Attributor::runTillFixpoint() {
2120 TimeTraceScope TimeScope("Attributor::runTillFixpoint");
2121 LLVM_DEBUG(dbgs() << "[Attributor] Identified and initialized "
2122 << DG.SyntheticRoot.Deps.size()
2123 << " abstract attributes.\n");
2124
2125 // Now that all abstract attributes are collected and initialized we start
2126 // the abstract analysis.
2127
2128 unsigned IterationCounter = 1;
2129 unsigned MaxIterations =
2130 Configuration.MaxFixpointIterations.value_or(u&: SetFixpointIterations);
2131
2132 SmallVector<AbstractAttribute *, 32> ChangedAAs;
2133 SetVector<AbstractAttribute *> Worklist, InvalidAAs;
2134 Worklist.insert(Start: DG.SyntheticRoot.begin(), End: DG.SyntheticRoot.end());
2135
2136 do {
2137 // Remember the size to determine new attributes.
2138 size_t NumAAs = DG.SyntheticRoot.Deps.size();
2139 LLVM_DEBUG(dbgs() << "\n\n[Attributor] #Iteration: " << IterationCounter
2140 << ", Worklist size: " << Worklist.size() << "\n");
2141
2142 // For invalid AAs we can fix dependent AAs that have a required dependence,
2143 // thereby folding long dependence chains in a single step without the need
2144 // to run updates.
2145 for (unsigned u = 0; u < InvalidAAs.size(); ++u) {
2146 AbstractAttribute *InvalidAA = InvalidAAs[u];
2147
2148 // Check the dependences to fast track invalidation.
2149 DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE,
2150 dbgs() << "[Attributor] InvalidAA: " << *InvalidAA
2151 << " has " << InvalidAA->Deps.size()
2152 << " required & optional dependences\n");
2153 for (auto &DepIt : InvalidAA->Deps) {
2154 AbstractAttribute *DepAA = cast<AbstractAttribute>(Val: DepIt.getPointer());
2155 if (DepIt.getInt() == unsigned(DepClassTy::OPTIONAL)) {
2156 DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE,
2157 dbgs() << " - recompute: " << *DepAA);
2158 Worklist.insert(X: DepAA);
2159 continue;
2160 }
2161 DEBUG_WITH_TYPE(VERBOSE_DEBUG_TYPE, dbgs()
2162 << " - invalidate: " << *DepAA);
2163 DepAA->getState().indicatePessimisticFixpoint();
2164 assert(DepAA->getState().isAtFixpoint() && "Expected fixpoint state!");
2165 if (!DepAA->getState().isValidState())
2166 InvalidAAs.insert(X: DepAA);
2167 else
2168 ChangedAAs.push_back(Elt: DepAA);
2169 }
2170 InvalidAA->Deps.clear();
2171 }
2172
2173 // Add all abstract attributes that are potentially dependent on one that
2174 // changed to the work list.
2175 for (AbstractAttribute *ChangedAA : ChangedAAs) {
2176 for (auto &DepIt : ChangedAA->Deps)
2177 Worklist.insert(X: cast<AbstractAttribute>(Val: DepIt.getPointer()));
2178 ChangedAA->Deps.clear();
2179 }
2180
2181 LLVM_DEBUG(dbgs() << "[Attributor] #Iteration: " << IterationCounter
2182 << ", Worklist+Dependent size: " << Worklist.size()
2183 << "\n");
2184
2185 // Reset the changed and invalid set.
2186 ChangedAAs.clear();
2187 InvalidAAs.clear();
2188
2189 // Update all abstract attribute in the work list and record the ones that
2190 // changed.
2191 for (AbstractAttribute *AA : Worklist) {
2192 const auto &AAState = AA->getState();
2193 if (!AAState.isAtFixpoint())
2194 if (updateAA(AA&: *AA) == ChangeStatus::CHANGED)
2195 ChangedAAs.push_back(Elt: AA);
2196
2197 // Use the InvalidAAs vector to propagate invalid states fast transitively
2198 // without requiring updates.
2199 if (!AAState.isValidState())
2200 InvalidAAs.insert(X: AA);
2201 }
2202
2203 // Add attributes to the changed set if they have been created in the last
2204 // iteration.
2205 ChangedAAs.append(in_start: DG.SyntheticRoot.begin() + NumAAs,
2206 in_end: DG.SyntheticRoot.end());
2207
2208 // Reset the work list and repopulate with the changed abstract attributes.
2209 // Note that dependent ones are added above.
2210 Worklist.clear();
2211 Worklist.insert(Start: ChangedAAs.begin(), End: ChangedAAs.end());
2212 Worklist.insert(Start: QueryAAsAwaitingUpdate.begin(),
2213 End: QueryAAsAwaitingUpdate.end());
2214 QueryAAsAwaitingUpdate.clear();
2215
2216 } while (!Worklist.empty() && (IterationCounter++ < MaxIterations));
2217
2218 if (IterationCounter > MaxIterations && !Functions.empty()) {
2219 auto Remark = [&](OptimizationRemarkMissed ORM) {
2220 return ORM << "Attributor did not reach a fixpoint after "
2221 << ore::NV("Iterations", MaxIterations) << " iterations.";
2222 };
2223 Function *F = Functions.front();
2224 emitRemark<OptimizationRemarkMissed>(F, RemarkName: "FixedPoint", RemarkCB&: Remark);
2225 }
2226
2227 LLVM_DEBUG(dbgs() << "\n[Attributor] Fixpoint iteration done after: "
2228 << IterationCounter << "/" << MaxIterations
2229 << " iterations\n");
2230
2231 // Reset abstract arguments not settled in a sound fixpoint by now. This
2232 // happens when we stopped the fixpoint iteration early. Note that only the
2233 // ones marked as "changed" *and* the ones transitively depending on them
2234 // need to be reverted to a pessimistic state. Others might not be in a
2235 // fixpoint state but we can use the optimistic results for them anyway.
2236 SmallPtrSet<AbstractAttribute *, 32> Visited;
2237 for (unsigned u = 0; u < ChangedAAs.size(); u++) {
2238 AbstractAttribute *ChangedAA = ChangedAAs[u];
2239 if (!Visited.insert(Ptr: ChangedAA).second)
2240 continue;
2241
2242 AbstractState &State = ChangedAA->getState();
2243 if (!State.isAtFixpoint()) {
2244 State.indicatePessimisticFixpoint();
2245
2246 NumAttributesTimedOut++;
2247 }
2248
2249 for (auto &DepIt : ChangedAA->Deps)
2250 ChangedAAs.push_back(Elt: cast<AbstractAttribute>(Val: DepIt.getPointer()));
2251 ChangedAA->Deps.clear();
2252 }
2253
2254 LLVM_DEBUG({
2255 if (!Visited.empty())
2256 dbgs() << "\n[Attributor] Finalized " << Visited.size()
2257 << " abstract attributes.\n";
2258 });
2259}
2260
2261void Attributor::registerForUpdate(AbstractAttribute &AA) {
2262 assert(AA.isQueryAA() &&
2263 "Non-query AAs should not be required to register for updates!");
2264 QueryAAsAwaitingUpdate.insert(X: &AA);
2265}
2266
2267ChangeStatus Attributor::manifestAttributes() {
2268 TimeTraceScope TimeScope("Attributor::manifestAttributes");
2269 size_t NumFinalAAs = DG.SyntheticRoot.Deps.size();
2270
2271 unsigned NumManifested = 0;
2272 unsigned NumAtFixpoint = 0;
2273 ChangeStatus ManifestChange = ChangeStatus::UNCHANGED;
2274 for (auto &DepAA : DG.SyntheticRoot.Deps) {
2275 AbstractAttribute *AA = cast<AbstractAttribute>(Val: DepAA.getPointer());
2276 AbstractState &State = AA->getState();
2277
2278 // If there is not already a fixpoint reached, we can now take the
2279 // optimistic state. This is correct because we enforced a pessimistic one
2280 // on abstract attributes that were transitively dependent on a changed one
2281 // already above.
2282 if (!State.isAtFixpoint())
2283 State.indicateOptimisticFixpoint();
2284
2285 // We must not manifest Attributes that use Callbase info.
2286 if (AA->hasCallBaseContext())
2287 continue;
2288 // If the state is invalid, we do not try to manifest it.
2289 if (!State.isValidState())
2290 continue;
2291
2292 if (AA->getCtxI() && !isRunOn(Fn&: *AA->getAnchorScope()))
2293 continue;
2294
2295 // Skip dead code.
2296 bool UsedAssumedInformation = false;
2297 if (isAssumedDead(AA: *AA, FnLivenessAA: nullptr, UsedAssumedInformation,
2298 /* CheckBBLivenessOnly */ true))
2299 continue;
2300 // Check if the manifest debug counter that allows skipping manifestation of
2301 // AAs
2302 if (!DebugCounter::shouldExecute(CounterName: ManifestDBGCounter))
2303 continue;
2304 // Manifest the state and record if we changed the IR.
2305 ChangeStatus LocalChange = AA->manifest(A&: *this);
2306 if (LocalChange == ChangeStatus::CHANGED && AreStatisticsEnabled())
2307 AA->trackStatistics();
2308 LLVM_DEBUG(dbgs() << "[Attributor] Manifest " << LocalChange << " : " << *AA
2309 << "\n");
2310
2311 ManifestChange = ManifestChange | LocalChange;
2312
2313 NumAtFixpoint++;
2314 NumManifested += (LocalChange == ChangeStatus::CHANGED);
2315 }
2316
2317 (void)NumManifested;
2318 (void)NumAtFixpoint;
2319 LLVM_DEBUG(dbgs() << "\n[Attributor] Manifested " << NumManifested
2320 << " arguments while " << NumAtFixpoint
2321 << " were in a valid fixpoint state\n");
2322
2323 NumAttributesManifested += NumManifested;
2324 NumAttributesValidFixpoint += NumAtFixpoint;
2325
2326 (void)NumFinalAAs;
2327 if (NumFinalAAs != DG.SyntheticRoot.Deps.size()) {
2328 auto DepIt = DG.SyntheticRoot.Deps.begin();
2329 for (unsigned u = 0; u < NumFinalAAs; ++u)
2330 ++DepIt;
2331 for (unsigned u = NumFinalAAs; u < DG.SyntheticRoot.Deps.size();
2332 ++u, ++DepIt) {
2333 errs() << "Unexpected abstract attribute: "
2334 << cast<AbstractAttribute>(Val: DepIt->getPointer()) << " :: "
2335 << cast<AbstractAttribute>(Val: DepIt->getPointer())
2336 ->getIRPosition()
2337 .getAssociatedValue()
2338 << "\n";
2339 }
2340 llvm_unreachable("Expected the final number of abstract attributes to "
2341 "remain unchanged!");
2342 }
2343
2344 for (auto &It : AttrsMap) {
2345 AttributeList &AL = It.getSecond();
2346 const IRPosition &IRP =
2347 isa<Function>(Val: It.getFirst())
2348 ? IRPosition::function(F: *cast<Function>(Val: It.getFirst()))
2349 : IRPosition::callsite_function(CB: *cast<CallBase>(Val: It.getFirst()));
2350 IRP.setAttrList(AL);
2351 }
2352
2353 return ManifestChange;
2354}
2355
2356void Attributor::identifyDeadInternalFunctions() {
2357 // Early exit if we don't intend to delete functions.
2358 if (!Configuration.DeleteFns)
2359 return;
2360
2361 // To avoid triggering an assertion in the lazy call graph we will not delete
2362 // any internal library functions. We should modify the assertion though and
2363 // allow internals to be deleted.
2364 const auto *TLI =
2365 isModulePass()
2366 ? nullptr
2367 : getInfoCache().getTargetLibraryInfoForFunction(F: *Functions.back());
2368 LibFunc LF;
2369
2370 // Identify dead internal functions and delete them. This happens outside
2371 // the other fixpoint analysis as we might treat potentially dead functions
2372 // as live to lower the number of iterations. If they happen to be dead, the
2373 // below fixpoint loop will identify and eliminate them.
2374
2375 SmallVector<Function *, 8> InternalFns;
2376 for (Function *F : Functions)
2377 if (F->hasLocalLinkage() && (isModulePass() || !TLI->getLibFunc(FDecl: *F, F&: LF)))
2378 InternalFns.push_back(Elt: F);
2379
2380 SmallPtrSet<Function *, 8> LiveInternalFns;
2381 bool FoundLiveInternal = true;
2382 while (FoundLiveInternal) {
2383 FoundLiveInternal = false;
2384 for (unsigned u = 0, e = InternalFns.size(); u < e; ++u) {
2385 Function *F = InternalFns[u];
2386 if (!F)
2387 continue;
2388
2389 bool UsedAssumedInformation = false;
2390 if (checkForAllCallSites(
2391 Pred: [&](AbstractCallSite ACS) {
2392 Function *Callee = ACS.getInstruction()->getFunction();
2393 return ToBeDeletedFunctions.count(key: Callee) ||
2394 (Functions.count(key: Callee) && Callee->hasLocalLinkage() &&
2395 !LiveInternalFns.count(Ptr: Callee));
2396 },
2397 Fn: *F, RequireAllCallSites: true, QueryingAA: nullptr, UsedAssumedInformation)) {
2398 continue;
2399 }
2400
2401 LiveInternalFns.insert(Ptr: F);
2402 InternalFns[u] = nullptr;
2403 FoundLiveInternal = true;
2404 }
2405 }
2406
2407 for (unsigned u = 0, e = InternalFns.size(); u < e; ++u)
2408 if (Function *F = InternalFns[u])
2409 ToBeDeletedFunctions.insert(X: F);
2410}
2411
2412ChangeStatus Attributor::cleanupIR() {
2413 TimeTraceScope TimeScope("Attributor::cleanupIR");
2414 // Delete stuff at the end to avoid invalid references and a nice order.
2415 LLVM_DEBUG(dbgs() << "\n[Attributor] Delete/replace at least "
2416 << ToBeDeletedFunctions.size() << " functions and "
2417 << ToBeDeletedBlocks.size() << " blocks and "
2418 << ToBeDeletedInsts.size() << " instructions and "
2419 << ToBeChangedValues.size() << " values and "
2420 << ToBeChangedUses.size() << " uses. To insert "
2421 << ToBeChangedToUnreachableInsts.size()
2422 << " unreachables.\n"
2423 << "Preserve manifest added " << ManifestAddedBlocks.size()
2424 << " blocks\n");
2425
2426 SmallVector<WeakTrackingVH, 32> DeadInsts;
2427 SmallVector<Instruction *, 32> TerminatorsToFold;
2428
2429 auto ReplaceUse = [&](Use *U, Value *NewV) {
2430 Value *OldV = U->get();
2431
2432 // If we plan to replace NewV we need to update it at this point.
2433 do {
2434 const auto &Entry = ToBeChangedValues.lookup(Key: NewV);
2435 if (!get<0>(Pair: Entry))
2436 break;
2437 NewV = get<0>(Pair: Entry);
2438 } while (true);
2439
2440 Instruction *I = dyn_cast<Instruction>(Val: U->getUser());
2441 assert((!I || isRunOn(*I->getFunction())) &&
2442 "Cannot replace an instruction outside the current SCC!");
2443
2444 // Do not replace uses in returns if the value is a must-tail call we will
2445 // not delete.
2446 if (auto *RI = dyn_cast_or_null<ReturnInst>(Val: I)) {
2447 if (auto *CI = dyn_cast<CallInst>(Val: OldV->stripPointerCasts()))
2448 if (CI->isMustTailCall() && !ToBeDeletedInsts.count(key: CI))
2449 return;
2450 // If we rewrite a return and the new value is not an argument, strip the
2451 // `returned` attribute as it is wrong now.
2452 if (!isa<Argument>(Val: NewV))
2453 for (auto &Arg : RI->getFunction()->args())
2454 Arg.removeAttr(Attribute::Kind: Returned);
2455 }
2456
2457 LLVM_DEBUG(dbgs() << "Use " << *NewV << " in " << *U->getUser()
2458 << " instead of " << *OldV << "\n");
2459 U->set(NewV);
2460
2461 if (Instruction *I = dyn_cast<Instruction>(Val: OldV)) {
2462 CGModifiedFunctions.insert(X: I->getFunction());
2463 if (!isa<PHINode>(Val: I) && !ToBeDeletedInsts.count(key: I) &&
2464 isInstructionTriviallyDead(I))
2465 DeadInsts.push_back(Elt: I);
2466 }
2467 if (isa<UndefValue>(Val: NewV) && isa<CallBase>(Val: U->getUser())) {
2468 auto *CB = cast<CallBase>(Val: U->getUser());
2469 if (CB->isArgOperand(U)) {
2470 unsigned Idx = CB->getArgOperandNo(U);
2471 CB->removeParamAttr(Idx, Attribute::NoUndef);
2472 auto *Callee = dyn_cast_if_present<Function>(Val: CB->getCalledOperand());
2473 if (Callee && Callee->arg_size() > Idx)
2474 Callee->removeParamAttr(Idx, Attribute::NoUndef);
2475 }
2476 }
2477 if (isa<Constant>(Val: NewV) && isa<BranchInst>(Val: U->getUser())) {
2478 Instruction *UserI = cast<Instruction>(Val: U->getUser());
2479 if (isa<UndefValue>(Val: NewV)) {
2480 ToBeChangedToUnreachableInsts.insert(X: UserI);
2481 } else {
2482 TerminatorsToFold.push_back(Elt: UserI);
2483 }
2484 }
2485 };
2486
2487 for (auto &It : ToBeChangedUses) {
2488 Use *U = It.first;
2489 Value *NewV = It.second;
2490 ReplaceUse(U, NewV);
2491 }
2492
2493 SmallVector<Use *, 4> Uses;
2494 for (auto &It : ToBeChangedValues) {
2495 Value *OldV = It.first;
2496 auto [NewV, Done] = It.second;
2497 Uses.clear();
2498 for (auto &U : OldV->uses())
2499 if (Done || !U.getUser()->isDroppable())
2500 Uses.push_back(Elt: &U);
2501 for (Use *U : Uses) {
2502 if (auto *I = dyn_cast<Instruction>(Val: U->getUser()))
2503 if (!isRunOn(Fn&: *I->getFunction()))
2504 continue;
2505 ReplaceUse(U, NewV);
2506 }
2507 }
2508
2509 for (const auto &V : InvokeWithDeadSuccessor)
2510 if (InvokeInst *II = dyn_cast_or_null<InvokeInst>(Val: V)) {
2511 assert(isRunOn(*II->getFunction()) &&
2512 "Cannot replace an invoke outside the current SCC!");
2513 bool UnwindBBIsDead = II->hasFnAttr(Attribute::NoUnwind);
2514 bool NormalBBIsDead = II->hasFnAttr(Attribute::NoReturn);
2515 bool Invoke2CallAllowed =
2516 !AAIsDead::mayCatchAsynchronousExceptions(F: *II->getFunction());
2517 assert((UnwindBBIsDead || NormalBBIsDead) &&
2518 "Invoke does not have dead successors!");
2519 BasicBlock *BB = II->getParent();
2520 BasicBlock *NormalDestBB = II->getNormalDest();
2521 if (UnwindBBIsDead) {
2522 Instruction *NormalNextIP = &NormalDestBB->front();
2523 if (Invoke2CallAllowed) {
2524 changeToCall(II);
2525 NormalNextIP = BB->getTerminator();
2526 }
2527 if (NormalBBIsDead)
2528 ToBeChangedToUnreachableInsts.insert(X: NormalNextIP);
2529 } else {
2530 assert(NormalBBIsDead && "Broken invariant!");
2531 if (!NormalDestBB->getUniquePredecessor())
2532 NormalDestBB = SplitBlockPredecessors(BB: NormalDestBB, Preds: {BB}, Suffix: ".dead");
2533 ToBeChangedToUnreachableInsts.insert(X: &NormalDestBB->front());
2534 }
2535 }
2536 for (Instruction *I : TerminatorsToFold) {
2537 assert(isRunOn(*I->getFunction()) &&
2538 "Cannot replace a terminator outside the current SCC!");
2539 CGModifiedFunctions.insert(X: I->getFunction());
2540 ConstantFoldTerminator(BB: I->getParent());
2541 }
2542 for (const auto &V : ToBeChangedToUnreachableInsts)
2543 if (Instruction *I = dyn_cast_or_null<Instruction>(Val: V)) {
2544 LLVM_DEBUG(dbgs() << "[Attributor] Change to unreachable: " << *I
2545 << "\n");
2546 assert(isRunOn(*I->getFunction()) &&
2547 "Cannot replace an instruction outside the current SCC!");
2548 CGModifiedFunctions.insert(X: I->getFunction());
2549 changeToUnreachable(I);
2550 }
2551
2552 for (const auto &V : ToBeDeletedInsts) {
2553 if (Instruction *I = dyn_cast_or_null<Instruction>(Val: V)) {
2554 if (auto *CB = dyn_cast<CallBase>(Val: I)) {
2555 assert((isa<IntrinsicInst>(CB) || isRunOn(*I->getFunction())) &&
2556 "Cannot delete an instruction outside the current SCC!");
2557 if (!isa<IntrinsicInst>(Val: CB))
2558 Configuration.CGUpdater.removeCallSite(CS&: *CB);
2559 }
2560 I->dropDroppableUses();
2561 CGModifiedFunctions.insert(X: I->getFunction());
2562 if (!I->getType()->isVoidTy())
2563 I->replaceAllUsesWith(V: UndefValue::get(T: I->getType()));
2564 if (!isa<PHINode>(Val: I) && isInstructionTriviallyDead(I))
2565 DeadInsts.push_back(Elt: I);
2566 else
2567 I->eraseFromParent();
2568 }
2569 }
2570
2571 llvm::erase_if(C&: DeadInsts, P: [&](WeakTrackingVH I) { return !I; });
2572
2573 LLVM_DEBUG({
2574 dbgs() << "[Attributor] DeadInsts size: " << DeadInsts.size() << "\n";
2575 for (auto &I : DeadInsts)
2576 if (I)
2577 dbgs() << " - " << *I << "\n";
2578 });
2579
2580 RecursivelyDeleteTriviallyDeadInstructions(DeadInsts);
2581
2582 if (unsigned NumDeadBlocks = ToBeDeletedBlocks.size()) {
2583 SmallVector<BasicBlock *, 8> ToBeDeletedBBs;
2584 ToBeDeletedBBs.reserve(N: NumDeadBlocks);
2585 for (BasicBlock *BB : ToBeDeletedBlocks) {
2586 assert(isRunOn(*BB->getParent()) &&
2587 "Cannot delete a block outside the current SCC!");
2588 CGModifiedFunctions.insert(X: BB->getParent());
2589 // Do not delete BBs added during manifests of AAs.
2590 if (ManifestAddedBlocks.contains(Ptr: BB))
2591 continue;
2592 ToBeDeletedBBs.push_back(Elt: BB);
2593 }
2594 // Actually we do not delete the blocks but squash them into a single
2595 // unreachable but untangling branches that jump here is something we need
2596 // to do in a more generic way.
2597 detachDeadBlocks(BBs: ToBeDeletedBBs, Updates: nullptr);
2598 }
2599
2600 identifyDeadInternalFunctions();
2601
2602 // Rewrite the functions as requested during manifest.
2603 ChangeStatus ManifestChange = rewriteFunctionSignatures(ModifiedFns&: CGModifiedFunctions);
2604
2605 for (Function *Fn : CGModifiedFunctions)
2606 if (!ToBeDeletedFunctions.count(key: Fn) && Functions.count(key: Fn))
2607 Configuration.CGUpdater.reanalyzeFunction(Fn&: *Fn);
2608
2609 for (Function *Fn : ToBeDeletedFunctions) {
2610 if (!Functions.count(key: Fn))
2611 continue;
2612 Configuration.CGUpdater.removeFunction(Fn&: *Fn);
2613 }
2614
2615 if (!ToBeChangedUses.empty())
2616 ManifestChange = ChangeStatus::CHANGED;
2617
2618 if (!ToBeChangedToUnreachableInsts.empty())
2619 ManifestChange = ChangeStatus::CHANGED;
2620
2621 if (!ToBeDeletedFunctions.empty())
2622 ManifestChange = ChangeStatus::CHANGED;
2623
2624 if (!ToBeDeletedBlocks.empty())
2625 ManifestChange = ChangeStatus::CHANGED;
2626
2627 if (!ToBeDeletedInsts.empty())
2628 ManifestChange = ChangeStatus::CHANGED;
2629
2630 if (!InvokeWithDeadSuccessor.empty())
2631 ManifestChange = ChangeStatus::CHANGED;
2632
2633 if (!DeadInsts.empty())
2634 ManifestChange = ChangeStatus::CHANGED;
2635
2636 NumFnDeleted += ToBeDeletedFunctions.size();
2637
2638 LLVM_DEBUG(dbgs() << "[Attributor] Deleted " << ToBeDeletedFunctions.size()
2639 << " functions after manifest.\n");
2640
2641#ifdef EXPENSIVE_CHECKS
2642 for (Function *F : Functions) {
2643 if (ToBeDeletedFunctions.count(F))
2644 continue;
2645 assert(!verifyFunction(*F, &errs()) && "Module verification failed!");
2646 }
2647#endif
2648
2649 return ManifestChange;
2650}
2651
2652ChangeStatus Attributor::run() {
2653 TimeTraceScope TimeScope("Attributor::run");
2654 AttributorCallGraph ACallGraph(*this);
2655
2656 if (PrintCallGraph)
2657 ACallGraph.populateAll();
2658
2659 Phase = AttributorPhase::UPDATE;
2660 runTillFixpoint();
2661
2662 // dump graphs on demand
2663 if (DumpDepGraph)
2664 DG.dumpGraph();
2665
2666 if (ViewDepGraph)
2667 DG.viewGraph();
2668
2669 if (PrintDependencies)
2670 DG.print();
2671
2672 Phase = AttributorPhase::MANIFEST;
2673 ChangeStatus ManifestChange = manifestAttributes();
2674
2675 Phase = AttributorPhase::CLEANUP;
2676 ChangeStatus CleanupChange = cleanupIR();
2677
2678 if (PrintCallGraph)
2679 ACallGraph.print();
2680
2681 return ManifestChange | CleanupChange;
2682}
2683
2684ChangeStatus Attributor::updateAA(AbstractAttribute &AA) {
2685 TimeTraceScope TimeScope("updateAA", [&]() {
2686 return AA.getName() + std::to_string(val: AA.getIRPosition().getPositionKind());
2687 });
2688 assert(Phase == AttributorPhase::UPDATE &&
2689 "We can update AA only in the update stage!");
2690
2691 // Use a new dependence vector for this update.
2692 DependenceVector DV;
2693 DependenceStack.push_back(Elt: &DV);
2694
2695 auto &AAState = AA.getState();
2696 ChangeStatus CS = ChangeStatus::UNCHANGED;
2697 bool UsedAssumedInformation = false;
2698 if (!isAssumedDead(AA, FnLivenessAA: nullptr, UsedAssumedInformation,
2699 /* CheckBBLivenessOnly */ true))
2700 CS = AA.update(A&: *this);
2701
2702 if (!AA.isQueryAA() && DV.empty() && !AA.getState().isAtFixpoint()) {
2703 // If the AA did not rely on outside information but changed, we run it
2704 // again to see if it found a fixpoint. Most AAs do but we don't require
2705 // them to. Hence, it might take the AA multiple iterations to get to a
2706 // fixpoint even if it does not rely on outside information, which is fine.
2707 ChangeStatus RerunCS = ChangeStatus::UNCHANGED;
2708 if (CS == ChangeStatus::CHANGED)
2709 RerunCS = AA.update(A&: *this);
2710
2711 // If the attribute did not change during the run or rerun, and it still did
2712 // not query any non-fix information, the state will not change and we can
2713 // indicate that right at this point.
2714 if (RerunCS == ChangeStatus::UNCHANGED && !AA.isQueryAA() && DV.empty())
2715 AAState.indicateOptimisticFixpoint();
2716 }
2717
2718 if (!AAState.isAtFixpoint())
2719 rememberDependences();
2720
2721 // Verify the stack was used properly, that is we pop the dependence vector we
2722 // put there earlier.
2723 DependenceVector *PoppedDV = DependenceStack.pop_back_val();
2724 (void)PoppedDV;
2725 assert(PoppedDV == &DV && "Inconsistent usage of the dependence stack!");
2726
2727 return CS;
2728}
2729
2730void Attributor::createShallowWrapper(Function &F) {
2731 assert(!F.isDeclaration() && "Cannot create a wrapper around a declaration!");
2732
2733 Module &M = *F.getParent();
2734 LLVMContext &Ctx = M.getContext();
2735 FunctionType *FnTy = F.getFunctionType();
2736
2737 Function *Wrapper =
2738 Function::Create(Ty: FnTy, Linkage: F.getLinkage(), AddrSpace: F.getAddressSpace(), N: F.getName());
2739 F.setName(""); // set the inside function anonymous
2740 M.getFunctionList().insert(where: F.getIterator(), New: Wrapper);
2741 // Flag whether the function is using new-debug-info or not.
2742 Wrapper->IsNewDbgInfoFormat = M.IsNewDbgInfoFormat;
2743
2744 F.setLinkage(GlobalValue::InternalLinkage);
2745
2746 F.replaceAllUsesWith(V: Wrapper);
2747 assert(F.use_empty() && "Uses remained after wrapper was created!");
2748
2749 // Move the COMDAT section to the wrapper.
2750 // TODO: Check if we need to keep it for F as well.
2751 Wrapper->setComdat(F.getComdat());
2752 F.setComdat(nullptr);
2753
2754 // Copy all metadata and attributes but keep them on F as well.
2755 SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
2756 F.getAllMetadata(MDs);
2757 for (auto MDIt : MDs)
2758 Wrapper->addMetadata(KindID: MDIt.first, MD&: *MDIt.second);
2759 Wrapper->setAttributes(F.getAttributes());
2760
2761 // Create the call in the wrapper.
2762 BasicBlock *EntryBB = BasicBlock::Create(Context&: Ctx, Name: "entry", Parent: Wrapper);
2763
2764 SmallVector<Value *, 8> Args;
2765 Argument *FArgIt = F.arg_begin();
2766 for (Argument &Arg : Wrapper->args()) {
2767 Args.push_back(Elt: &Arg);
2768 Arg.setName((FArgIt++)->getName());
2769 }
2770
2771 CallInst *CI = CallInst::Create(Func: &F, Args, NameStr: "", InsertAtEnd: EntryBB);
2772 CI->setTailCall(true);
2773 CI->addFnAttr(Attribute::NoInline);
2774 ReturnInst::Create(C&: Ctx, retVal: CI->getType()->isVoidTy() ? nullptr : CI, InsertAtEnd: EntryBB);
2775
2776 NumFnShallowWrappersCreated++;
2777}
2778
2779bool Attributor::isInternalizable(Function &F) {
2780 if (F.isDeclaration() || F.hasLocalLinkage() ||
2781 GlobalValue::isInterposableLinkage(Linkage: F.getLinkage()))
2782 return false;
2783 return true;
2784}
2785
2786Function *Attributor::internalizeFunction(Function &F, bool Force) {
2787 if (!AllowDeepWrapper && !Force)
2788 return nullptr;
2789 if (!isInternalizable(F))
2790 return nullptr;
2791
2792 SmallPtrSet<Function *, 2> FnSet = {&F};
2793 DenseMap<Function *, Function *> InternalizedFns;
2794 internalizeFunctions(FnSet, FnMap&: InternalizedFns);
2795
2796 return InternalizedFns[&F];
2797}
2798
2799bool Attributor::internalizeFunctions(SmallPtrSetImpl<Function *> &FnSet,
2800 DenseMap<Function *, Function *> &FnMap) {
2801 for (Function *F : FnSet)
2802 if (!Attributor::isInternalizable(F&: *F))
2803 return false;
2804
2805 FnMap.clear();
2806 // Generate the internalized version of each function.
2807 for (Function *F : FnSet) {
2808 Module &M = *F->getParent();
2809 FunctionType *FnTy = F->getFunctionType();
2810
2811 // Create a copy of the current function
2812 Function *Copied =
2813 Function::Create(Ty: FnTy, Linkage: F->getLinkage(), AddrSpace: F->getAddressSpace(),
2814 N: F->getName() + ".internalized");
2815 ValueToValueMapTy VMap;
2816 auto *NewFArgIt = Copied->arg_begin();
2817 for (auto &Arg : F->args()) {
2818 auto ArgName = Arg.getName();
2819 NewFArgIt->setName(ArgName);
2820 VMap[&Arg] = &(*NewFArgIt++);
2821 }
2822 SmallVector<ReturnInst *, 8> Returns;
2823 // Flag whether the function is using new-debug-info or not.
2824 Copied->IsNewDbgInfoFormat = F->IsNewDbgInfoFormat;
2825
2826 // Copy the body of the original function to the new one
2827 CloneFunctionInto(NewFunc: Copied, OldFunc: F, VMap,
2828 Changes: CloneFunctionChangeType::LocalChangesOnly, Returns);
2829
2830 // Set the linakage and visibility late as CloneFunctionInto has some
2831 // implicit requirements.
2832 Copied->setVisibility(GlobalValue::DefaultVisibility);
2833 Copied->setLinkage(GlobalValue::PrivateLinkage);
2834
2835 // Copy metadata
2836 SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
2837 F->getAllMetadata(MDs);
2838 for (auto MDIt : MDs)
2839 if (!Copied->hasMetadata())
2840 Copied->addMetadata(KindID: MDIt.first, MD&: *MDIt.second);
2841
2842 M.getFunctionList().insert(where: F->getIterator(), New: Copied);
2843 Copied->setDSOLocal(true);
2844 FnMap[F] = Copied;
2845 }
2846
2847 // Replace all uses of the old function with the new internalized function
2848 // unless the caller is a function that was just internalized.
2849 for (Function *F : FnSet) {
2850 auto &InternalizedFn = FnMap[F];
2851 auto IsNotInternalized = [&](Use &U) -> bool {
2852 if (auto *CB = dyn_cast<CallBase>(Val: U.getUser()))
2853 return !FnMap.lookup(Val: CB->getCaller());
2854 return false;
2855 };
2856 F->replaceUsesWithIf(New: InternalizedFn, ShouldReplace: IsNotInternalized);
2857 }
2858
2859 return true;
2860}
2861
2862bool Attributor::isValidFunctionSignatureRewrite(
2863 Argument &Arg, ArrayRef<Type *> ReplacementTypes) {
2864
2865 if (!Configuration.RewriteSignatures)
2866 return false;
2867
2868 Function *Fn = Arg.getParent();
2869 auto CallSiteCanBeChanged = [Fn](AbstractCallSite ACS) {
2870 // Forbid the call site to cast the function return type. If we need to
2871 // rewrite these functions we need to re-create a cast for the new call site
2872 // (if the old had uses).
2873 if (!ACS.getCalledFunction() ||
2874 ACS.getInstruction()->getType() !=
2875 ACS.getCalledFunction()->getReturnType())
2876 return false;
2877 if (cast<CallBase>(Val: ACS.getInstruction())->getCalledOperand()->getType() !=
2878 Fn->getType())
2879 return false;
2880 if (ACS.getNumArgOperands() != Fn->arg_size())
2881 return false;
2882 // Forbid must-tail calls for now.
2883 return !ACS.isCallbackCall() && !ACS.getInstruction()->isMustTailCall();
2884 };
2885
2886 // Avoid var-arg functions for now.
2887 if (Fn->isVarArg()) {
2888 LLVM_DEBUG(dbgs() << "[Attributor] Cannot rewrite var-args functions\n");
2889 return false;
2890 }
2891
2892 // Avoid functions with complicated argument passing semantics.
2893 AttributeList FnAttributeList = Fn->getAttributes();
2894 if (FnAttributeList.hasAttrSomewhere(Attribute::Kind: Nest) ||
2895 FnAttributeList.hasAttrSomewhere(Attribute::Kind: StructRet) ||
2896 FnAttributeList.hasAttrSomewhere(Attribute::Kind: InAlloca) ||
2897 FnAttributeList.hasAttrSomewhere(Attribute::Kind: Preallocated)) {
2898 LLVM_DEBUG(
2899 dbgs() << "[Attributor] Cannot rewrite due to complex attribute\n");
2900 return false;
2901 }
2902
2903 // Avoid callbacks for now.
2904 bool UsedAssumedInformation = false;
2905 if (!checkForAllCallSites(Pred: CallSiteCanBeChanged, Fn: *Fn, RequireAllCallSites: true, QueryingAA: nullptr,
2906 UsedAssumedInformation,
2907 /* CheckPotentiallyDead */ true)) {
2908 LLVM_DEBUG(dbgs() << "[Attributor] Cannot rewrite all call sites\n");
2909 return false;
2910 }
2911
2912 auto InstPred = [](Instruction &I) {
2913 if (auto *CI = dyn_cast<CallInst>(Val: &I))
2914 return !CI->isMustTailCall();
2915 return true;
2916 };
2917
2918 // Forbid must-tail calls for now.
2919 // TODO:
2920 auto &OpcodeInstMap = InfoCache.getOpcodeInstMapForFunction(F: *Fn);
2921 if (!checkForAllInstructionsImpl(A: nullptr, OpcodeInstMap, Pred: InstPred, QueryingAA: nullptr,
2922 LivenessAA: nullptr, Opcodes: {Instruction::Call},
2923 UsedAssumedInformation)) {
2924 LLVM_DEBUG(dbgs() << "[Attributor] Cannot rewrite due to instructions\n");
2925 return false;
2926 }
2927
2928 return true;
2929}
2930
2931bool Attributor::registerFunctionSignatureRewrite(
2932 Argument &Arg, ArrayRef<Type *> ReplacementTypes,
2933 ArgumentReplacementInfo::CalleeRepairCBTy &&CalleeRepairCB,
2934 ArgumentReplacementInfo::ACSRepairCBTy &&ACSRepairCB) {
2935 LLVM_DEBUG(dbgs() << "[Attributor] Register new rewrite of " << Arg << " in "
2936 << Arg.getParent()->getName() << " with "
2937 << ReplacementTypes.size() << " replacements\n");
2938 assert(isValidFunctionSignatureRewrite(Arg, ReplacementTypes) &&
2939 "Cannot register an invalid rewrite");
2940
2941 Function *Fn = Arg.getParent();
2942 SmallVectorImpl<std::unique_ptr<ArgumentReplacementInfo>> &ARIs =
2943 ArgumentReplacementMap[Fn];
2944 if (ARIs.empty())
2945 ARIs.resize(N: Fn->arg_size());
2946
2947 // If we have a replacement already with less than or equal new arguments,
2948 // ignore this request.
2949 std::unique_ptr<ArgumentReplacementInfo> &ARI = ARIs[Arg.getArgNo()];
2950 if (ARI && ARI->getNumReplacementArgs() <= ReplacementTypes.size()) {
2951 LLVM_DEBUG(dbgs() << "[Attributor] Existing rewrite is preferred\n");
2952 return false;
2953 }
2954
2955 // If we have a replacement already but we like the new one better, delete
2956 // the old.
2957 ARI.reset();
2958
2959 LLVM_DEBUG(dbgs() << "[Attributor] Register new rewrite of " << Arg << " in "
2960 << Arg.getParent()->getName() << " with "
2961 << ReplacementTypes.size() << " replacements\n");
2962
2963 // Remember the replacement.
2964 ARI.reset(p: new ArgumentReplacementInfo(*this, Arg, ReplacementTypes,
2965 std::move(CalleeRepairCB),
2966 std::move(ACSRepairCB)));
2967
2968 return true;
2969}
2970
2971bool Attributor::shouldSeedAttribute(AbstractAttribute &AA) {
2972 bool Result = true;
2973#ifndef NDEBUG
2974 if (SeedAllowList.size() != 0)
2975 Result = llvm::is_contained(Range&: SeedAllowList, Element: AA.getName());
2976 Function *Fn = AA.getAnchorScope();
2977 if (FunctionSeedAllowList.size() != 0 && Fn)
2978 Result &= llvm::is_contained(Range&: FunctionSeedAllowList, Element: Fn->getName());
2979#endif
2980 return Result;
2981}
2982
2983ChangeStatus Attributor::rewriteFunctionSignatures(
2984 SmallSetVector<Function *, 8> &ModifiedFns) {
2985 ChangeStatus Changed = ChangeStatus::UNCHANGED;
2986
2987 for (auto &It : ArgumentReplacementMap) {
2988 Function *OldFn = It.getFirst();
2989
2990 // Deleted functions do not require rewrites.
2991 if (!Functions.count(key: OldFn) || ToBeDeletedFunctions.count(key: OldFn))
2992 continue;
2993
2994 const SmallVectorImpl<std::unique_ptr<ArgumentReplacementInfo>> &ARIs =
2995 It.getSecond();
2996 assert(ARIs.size() == OldFn->arg_size() && "Inconsistent state!");
2997
2998 SmallVector<Type *, 16> NewArgumentTypes;
2999 SmallVector<AttributeSet, 16> NewArgumentAttributes;
3000
3001 // Collect replacement argument types and copy over existing attributes.
3002 AttributeList OldFnAttributeList = OldFn->getAttributes();
3003 for (Argument &Arg : OldFn->args()) {
3004 if (const std::unique_ptr<ArgumentReplacementInfo> &ARI =
3005 ARIs[Arg.getArgNo()]) {
3006 NewArgumentTypes.append(in_start: ARI->ReplacementTypes.begin(),
3007 in_end: ARI->ReplacementTypes.end());
3008 NewArgumentAttributes.append(NumInputs: ARI->getNumReplacementArgs(),
3009 Elt: AttributeSet());
3010 } else {
3011 NewArgumentTypes.push_back(Elt: Arg.getType());
3012 NewArgumentAttributes.push_back(
3013 Elt: OldFnAttributeList.getParamAttrs(ArgNo: Arg.getArgNo()));
3014 }
3015 }
3016
3017 uint64_t LargestVectorWidth = 0;
3018 for (auto *I : NewArgumentTypes)
3019 if (auto *VT = dyn_cast<llvm::VectorType>(Val: I))
3020 LargestVectorWidth =
3021 std::max(a: LargestVectorWidth,
3022 b: VT->getPrimitiveSizeInBits().getKnownMinValue());
3023
3024 FunctionType *OldFnTy = OldFn->getFunctionType();
3025 Type *RetTy = OldFnTy->getReturnType();
3026
3027 // Construct the new function type using the new arguments types.
3028 FunctionType *NewFnTy =
3029 FunctionType::get(Result: RetTy, Params: NewArgumentTypes, isVarArg: OldFnTy->isVarArg());
3030
3031 LLVM_DEBUG(dbgs() << "[Attributor] Function rewrite '" << OldFn->getName()
3032 << "' from " << *OldFn->getFunctionType() << " to "
3033 << *NewFnTy << "\n");
3034
3035 // Create the new function body and insert it into the module.
3036 Function *NewFn = Function::Create(Ty: NewFnTy, Linkage: OldFn->getLinkage(),
3037 AddrSpace: OldFn->getAddressSpace(), N: "");
3038 Functions.insert(X: NewFn);
3039 OldFn->getParent()->getFunctionList().insert(where: OldFn->getIterator(), New: NewFn);
3040 NewFn->takeName(V: OldFn);
3041 NewFn->copyAttributesFrom(Src: OldFn);
3042 // Flag whether the function is using new-debug-info or not.
3043 NewFn->IsNewDbgInfoFormat = OldFn->IsNewDbgInfoFormat;
3044
3045 // Patch the pointer to LLVM function in debug info descriptor.
3046 NewFn->setSubprogram(OldFn->getSubprogram());
3047 OldFn->setSubprogram(nullptr);
3048
3049 // Recompute the parameter attributes list based on the new arguments for
3050 // the function.
3051 LLVMContext &Ctx = OldFn->getContext();
3052 NewFn->setAttributes(AttributeList::get(
3053 C&: Ctx, FnAttrs: OldFnAttributeList.getFnAttrs(), RetAttrs: OldFnAttributeList.getRetAttrs(),
3054 ArgAttrs: NewArgumentAttributes));
3055 AttributeFuncs::updateMinLegalVectorWidthAttr(Fn&: *NewFn, Width: LargestVectorWidth);
3056
3057 // Remove argmem from the memory effects if we have no more pointer
3058 // arguments, or they are readnone.
3059 MemoryEffects ME = NewFn->getMemoryEffects();
3060 int ArgNo = -1;
3061 if (ME.doesAccessArgPointees() && all_of(Range&: NewArgumentTypes, P: [&](Type *T) {
3062 ++ArgNo;
3063 return !T->isPtrOrPtrVectorTy() ||
3064 NewFn->hasParamAttribute(ArgNo, Attribute::ReadNone);
3065 })) {
3066 NewFn->setMemoryEffects(ME - MemoryEffects::argMemOnly());
3067 }
3068
3069 // Since we have now created the new function, splice the body of the old
3070 // function right into the new function, leaving the old rotting hulk of the
3071 // function empty.
3072 NewFn->splice(ToIt: NewFn->begin(), FromF: OldFn);
3073
3074 // Fixup block addresses to reference new function.
3075 SmallVector<BlockAddress *, 8u> BlockAddresses;
3076 for (User *U : OldFn->users())
3077 if (auto *BA = dyn_cast<BlockAddress>(Val: U))
3078 BlockAddresses.push_back(Elt: BA);
3079 for (auto *BA : BlockAddresses)
3080 BA->replaceAllUsesWith(V: BlockAddress::get(F: NewFn, BB: BA->getBasicBlock()));
3081
3082 // Set of all "call-like" instructions that invoke the old function mapped
3083 // to their new replacements.
3084 SmallVector<std::pair<CallBase *, CallBase *>, 8> CallSitePairs;
3085
3086 // Callback to create a new "call-like" instruction for a given one.
3087 auto CallSiteReplacementCreator = [&](AbstractCallSite ACS) {
3088 CallBase *OldCB = cast<CallBase>(Val: ACS.getInstruction());
3089 const AttributeList &OldCallAttributeList = OldCB->getAttributes();
3090
3091 // Collect the new argument operands for the replacement call site.
3092 SmallVector<Value *, 16> NewArgOperands;
3093 SmallVector<AttributeSet, 16> NewArgOperandAttributes;
3094 for (unsigned OldArgNum = 0; OldArgNum < ARIs.size(); ++OldArgNum) {
3095 unsigned NewFirstArgNum = NewArgOperands.size();
3096 (void)NewFirstArgNum; // only used inside assert.
3097 if (const std::unique_ptr<ArgumentReplacementInfo> &ARI =
3098 ARIs[OldArgNum]) {
3099 if (ARI->ACSRepairCB)
3100 ARI->ACSRepairCB(*ARI, ACS, NewArgOperands);
3101 assert(ARI->getNumReplacementArgs() + NewFirstArgNum ==
3102 NewArgOperands.size() &&
3103 "ACS repair callback did not provide as many operand as new "
3104 "types were registered!");
3105 // TODO: Exose the attribute set to the ACS repair callback
3106 NewArgOperandAttributes.append(NumInputs: ARI->ReplacementTypes.size(),
3107 Elt: AttributeSet());
3108 } else {
3109 NewArgOperands.push_back(Elt: ACS.getCallArgOperand(ArgNo: OldArgNum));
3110 NewArgOperandAttributes.push_back(
3111 Elt: OldCallAttributeList.getParamAttrs(ArgNo: OldArgNum));
3112 }
3113 }
3114
3115 assert(NewArgOperands.size() == NewArgOperandAttributes.size() &&
3116 "Mismatch # argument operands vs. # argument operand attributes!");
3117 assert(NewArgOperands.size() == NewFn->arg_size() &&
3118 "Mismatch # argument operands vs. # function arguments!");
3119
3120 SmallVector<OperandBundleDef, 4> OperandBundleDefs;
3121 OldCB->getOperandBundlesAsDefs(Defs&: OperandBundleDefs);
3122
3123 // Create a new call or invoke instruction to replace the old one.
3124 CallBase *NewCB;
3125 if (InvokeInst *II = dyn_cast<InvokeInst>(Val: OldCB)) {
3126 NewCB = InvokeInst::Create(Func: NewFn, IfNormal: II->getNormalDest(),
3127 IfException: II->getUnwindDest(), Args: NewArgOperands,
3128 Bundles: OperandBundleDefs, NameStr: "", InsertBefore: OldCB->getIterator());
3129 } else {
3130 auto *NewCI = CallInst::Create(Func: NewFn, Args: NewArgOperands, Bundles: OperandBundleDefs,
3131 NameStr: "", InsertBefore: OldCB->getIterator());
3132 NewCI->setTailCallKind(cast<CallInst>(Val: OldCB)->getTailCallKind());
3133 NewCB = NewCI;
3134 }
3135
3136 // Copy over various properties and the new attributes.
3137 NewCB->copyMetadata(SrcInst: *OldCB, WL: {LLVMContext::MD_prof, LLVMContext::MD_dbg});
3138 NewCB->setCallingConv(OldCB->getCallingConv());
3139 NewCB->takeName(V: OldCB);
3140 NewCB->setAttributes(AttributeList::get(
3141 C&: Ctx, FnAttrs: OldCallAttributeList.getFnAttrs(),
3142 RetAttrs: OldCallAttributeList.getRetAttrs(), ArgAttrs: NewArgOperandAttributes));
3143
3144 AttributeFuncs::updateMinLegalVectorWidthAttr(Fn&: *NewCB->getCaller(),
3145 Width: LargestVectorWidth);
3146
3147 CallSitePairs.push_back(Elt: {OldCB, NewCB});
3148 return true;
3149 };
3150
3151 // Use the CallSiteReplacementCreator to create replacement call sites.
3152 bool UsedAssumedInformation = false;
3153 bool Success = checkForAllCallSites(Pred: CallSiteReplacementCreator, Fn: *OldFn,
3154 RequireAllCallSites: true, QueryingAA: nullptr, UsedAssumedInformation,
3155 /* CheckPotentiallyDead */ true);
3156 (void)Success;
3157 assert(Success && "Assumed call site replacement to succeed!");
3158
3159 // Rewire the arguments.
3160 Argument *OldFnArgIt = OldFn->arg_begin();
3161 Argument *NewFnArgIt = NewFn->arg_begin();
3162 for (unsigned OldArgNum = 0; OldArgNum < ARIs.size();
3163 ++OldArgNum, ++OldFnArgIt) {
3164 if (const std::unique_ptr<ArgumentReplacementInfo> &ARI =
3165 ARIs[OldArgNum]) {
3166 if (ARI->CalleeRepairCB)
3167 ARI->CalleeRepairCB(*ARI, *NewFn, NewFnArgIt);
3168 if (ARI->ReplacementTypes.empty())
3169 OldFnArgIt->replaceAllUsesWith(
3170 V: PoisonValue::get(T: OldFnArgIt->getType()));
3171 NewFnArgIt += ARI->ReplacementTypes.size();
3172 } else {
3173 NewFnArgIt->takeName(V: &*OldFnArgIt);
3174 OldFnArgIt->replaceAllUsesWith(V: &*NewFnArgIt);
3175 ++NewFnArgIt;
3176 }
3177 }
3178
3179 // Eliminate the instructions *after* we visited all of them.
3180 for (auto &CallSitePair : CallSitePairs) {
3181 CallBase &OldCB = *CallSitePair.first;
3182 CallBase &NewCB = *CallSitePair.second;
3183 assert(OldCB.getType() == NewCB.getType() &&
3184 "Cannot handle call sites with different types!");
3185 ModifiedFns.insert(X: OldCB.getFunction());
3186 Configuration.CGUpdater.replaceCallSite(OldCS&: OldCB, NewCS&: NewCB);
3187 OldCB.replaceAllUsesWith(V: &NewCB);
3188 OldCB.eraseFromParent();
3189 }
3190
3191 // Replace the function in the call graph (if any).
3192 Configuration.CGUpdater.replaceFunctionWith(OldFn&: *OldFn, NewFn&: *NewFn);
3193
3194 // If the old function was modified and needed to be reanalyzed, the new one
3195 // does now.
3196 if (ModifiedFns.remove(X: OldFn))
3197 ModifiedFns.insert(X: NewFn);
3198
3199 Changed = ChangeStatus::CHANGED;
3200 }
3201
3202 return Changed;
3203}
3204
3205void InformationCache::initializeInformationCache(const Function &CF,
3206 FunctionInfo &FI) {
3207 // As we do not modify the function here we can remove the const
3208 // withouth breaking implicit assumptions. At the end of the day, we could
3209 // initialize the cache eagerly which would look the same to the users.
3210 Function &F = const_cast<Function &>(CF);
3211
3212 // Walk all instructions to find interesting instructions that might be
3213 // queried by abstract attributes during their initialization or update.
3214 // This has to happen before we create attributes.
3215
3216 DenseMap<const Value *, std::optional<short>> AssumeUsesMap;
3217
3218 // Add \p V to the assume uses map which track the number of uses outside of
3219 // "visited" assumes. If no outside uses are left the value is added to the
3220 // assume only use vector.
3221 auto AddToAssumeUsesMap = [&](const Value &V) -> void {
3222 SmallVector<const Instruction *> Worklist;
3223 if (auto *I = dyn_cast<Instruction>(Val: &V))
3224 Worklist.push_back(Elt: I);
3225 while (!Worklist.empty()) {
3226 const Instruction *I = Worklist.pop_back_val();
3227 std::optional<short> &NumUses = AssumeUsesMap[I];
3228 if (!NumUses)
3229 NumUses = I->getNumUses();
3230 NumUses = *NumUses - /* this assume */ 1;
3231 if (*NumUses != 0)
3232 continue;
3233 AssumeOnlyValues.insert(X: I);
3234 for (const Value *Op : I->operands())
3235 if (auto *OpI = dyn_cast<Instruction>(Val: Op))
3236 Worklist.push_back(Elt: OpI);
3237 }
3238 };
3239
3240 for (Instruction &I : instructions(F: &F)) {
3241 bool IsInterestingOpcode = false;
3242
3243 // To allow easy access to all instructions in a function with a given
3244 // opcode we store them in the InfoCache. As not all opcodes are interesting
3245 // to concrete attributes we only cache the ones that are as identified in
3246 // the following switch.
3247 // Note: There are no concrete attributes now so this is initially empty.
3248 switch (I.getOpcode()) {
3249 default:
3250 assert(!isa<CallBase>(&I) &&
3251 "New call base instruction type needs to be known in the "
3252 "Attributor.");
3253 break;
3254 case Instruction::Call:
3255 // Calls are interesting on their own, additionally:
3256 // For `llvm.assume` calls we also fill the KnowledgeMap as we find them.
3257 // For `must-tail` calls we remember the caller and callee.
3258 if (auto *Assume = dyn_cast<AssumeInst>(Val: &I)) {
3259 AssumeOnlyValues.insert(X: Assume);
3260 fillMapFromAssume(Assume&: *Assume, Result&: KnowledgeMap);
3261 AddToAssumeUsesMap(*Assume->getArgOperand(i: 0));
3262 } else if (cast<CallInst>(Val&: I).isMustTailCall()) {
3263 FI.ContainsMustTailCall = true;
3264 if (auto *Callee = dyn_cast_if_present<Function>(
3265 Val: cast<CallInst>(Val&: I).getCalledOperand()))
3266 getFunctionInfo(F: *Callee).CalledViaMustTail = true;
3267 }
3268 [[fallthrough]];
3269 case Instruction::CallBr:
3270 case Instruction::Invoke:
3271 case Instruction::CleanupRet:
3272 case Instruction::CatchSwitch:
3273 case Instruction::AtomicRMW:
3274 case Instruction::AtomicCmpXchg:
3275 case Instruction::Br:
3276 case Instruction::Resume:
3277 case Instruction::Ret:
3278 case Instruction::Load:
3279 // The alignment of a pointer is interesting for loads.
3280 case Instruction::Store:
3281 // The alignment of a pointer is interesting for stores.
3282 case Instruction::Alloca:
3283 case Instruction::AddrSpaceCast:
3284 IsInterestingOpcode = true;
3285 }
3286 if (IsInterestingOpcode) {
3287 auto *&Insts = FI.OpcodeInstMap[I.getOpcode()];
3288 if (!Insts)
3289 Insts = new (Allocator) InstructionVectorTy();
3290 Insts->push_back(Elt: &I);
3291 }
3292 if (I.mayReadOrWriteMemory())
3293 FI.RWInsts.push_back(Elt: &I);
3294 }
3295
3296 if (F.hasFnAttribute(Attribute::AlwaysInline) &&
3297 isInlineViable(Callee&: F).isSuccess())
3298 InlineableFunctions.insert(Ptr: &F);
3299}
3300
3301InformationCache::FunctionInfo::~FunctionInfo() {
3302 // The instruction vectors are allocated using a BumpPtrAllocator, we need to
3303 // manually destroy them.
3304 for (auto &It : OpcodeInstMap)
3305 It.getSecond()->~InstructionVectorTy();
3306}
3307
3308const ArrayRef<Function *>
3309InformationCache::getIndirectlyCallableFunctions(Attributor &A) const {
3310 assert(A.isClosedWorldModule() && "Cannot see all indirect callees!");
3311 return IndirectlyCallableFunctions;
3312}
3313
3314void Attributor::recordDependence(const AbstractAttribute &FromAA,
3315 const AbstractAttribute &ToAA,
3316 DepClassTy DepClass) {
3317 if (DepClass == DepClassTy::NONE)
3318 return;
3319 // If we are outside of an update, thus before the actual fixpoint iteration
3320 // started (= when we create AAs), we do not track dependences because we will
3321 // put all AAs into the initial worklist anyway.
3322 if (DependenceStack.empty())
3323 return;
3324 if (FromAA.getState().isAtFixpoint())
3325 return;
3326 DependenceStack.back()->push_back(Elt: {.FromAA: &FromAA, .ToAA: &ToAA, .DepClass: DepClass});
3327}
3328
3329void Attributor::rememberDependences() {
3330 assert(!DependenceStack.empty() && "No dependences to remember!");
3331
3332 for (DepInfo &DI : *DependenceStack.back()) {
3333 assert((DI.DepClass == DepClassTy::REQUIRED ||
3334 DI.DepClass == DepClassTy::OPTIONAL) &&
3335 "Expected required or optional dependence (1 bit)!");
3336 auto &DepAAs = const_cast<AbstractAttribute &>(*DI.FromAA).Deps;
3337 DepAAs.insert(X: AbstractAttribute::DepTy(
3338 const_cast<AbstractAttribute *>(DI.ToAA), unsigned(DI.DepClass)));
3339 }
3340}
3341
3342template <Attribute::AttrKind AK, typename AAType>
3343void Attributor::checkAndQueryIRAttr(const IRPosition &IRP,
3344 AttributeSet Attrs) {
3345 bool IsKnown;
3346 if (!Attrs.hasAttribute(Kind: AK))
3347 if (!Configuration.Allowed || Configuration.Allowed->count(V: &AAType::ID))
3348 if (!AA::hasAssumedIRAttr<AK>(*this, nullptr, IRP, DepClassTy::NONE,
3349 IsKnown))
3350 getOrCreateAAFor<AAType>(IRP);
3351}
3352
3353void Attributor::identifyDefaultAbstractAttributes(Function &F) {
3354 if (!VisitedFunctions.insert(V: &F).second)
3355 return;
3356 if (F.isDeclaration())
3357 return;
3358
3359 // In non-module runs we need to look at the call sites of a function to
3360 // determine if it is part of a must-tail call edge. This will influence what
3361 // attributes we can derive.
3362 InformationCache::FunctionInfo &FI = InfoCache.getFunctionInfo(F);
3363 if (!isModulePass() && !FI.CalledViaMustTail) {
3364 for (const Use &U : F.uses())
3365 if (const auto *CB = dyn_cast<CallBase>(Val: U.getUser()))
3366 if (CB->isCallee(U: &U) && CB->isMustTailCall())
3367 FI.CalledViaMustTail = true;
3368 }
3369
3370 IRPosition FPos = IRPosition::function(F);
3371 bool IsIPOAmendable = isFunctionIPOAmendable(F);
3372 auto Attrs = F.getAttributes();
3373 auto FnAttrs = Attrs.getFnAttrs();
3374
3375 // Check for dead BasicBlocks in every function.
3376 // We need dead instruction detection because we do not want to deal with
3377 // broken IR in which SSA rules do not apply.
3378 getOrCreateAAFor<AAIsDead>(IRP: FPos);
3379
3380 // Every function might contain instructions that cause "undefined
3381 // behavior".
3382 getOrCreateAAFor<AAUndefinedBehavior>(IRP: FPos);
3383
3384 // Every function might be applicable for Heap-To-Stack conversion.
3385 if (EnableHeapToStack)
3386 getOrCreateAAFor<AAHeapToStack>(IRP: FPos);
3387
3388 // Every function might be "must-progress".
3389 checkAndQueryIRAttr<Attribute::MustProgress, AAMustProgress>(FPos, FnAttrs);
3390
3391 // Every function might be "no-free".
3392 checkAndQueryIRAttr<Attribute::NoFree, AANoFree>(FPos, FnAttrs);
3393
3394 // Every function might be "will-return".
3395 checkAndQueryIRAttr<Attribute::WillReturn, AAWillReturn>(FPos, FnAttrs);
3396
3397 // Every function might be marked "nosync"
3398 checkAndQueryIRAttr<Attribute::NoSync, AANoSync>(FPos, FnAttrs);
3399
3400 // Everything that is visible from the outside (=function, argument, return
3401 // positions), cannot be changed if the function is not IPO amendable. We can
3402 // however analyse the code inside.
3403 if (IsIPOAmendable) {
3404
3405 // Every function can be nounwind.
3406 checkAndQueryIRAttr<Attribute::NoUnwind, AANoUnwind>(FPos, FnAttrs);
3407
3408 // Every function might be "no-return".
3409 checkAndQueryIRAttr<Attribute::NoReturn, AANoReturn>(FPos, FnAttrs);
3410
3411 // Every function might be "no-recurse".
3412 checkAndQueryIRAttr<Attribute::NoRecurse, AANoRecurse>(FPos, FnAttrs);
3413
3414 // Every function can be "non-convergent".
3415 if (Attrs.hasFnAttr(Attribute::Convergent))
3416 getOrCreateAAFor<AANonConvergent>(IRP: FPos);
3417
3418 // Every function might be "readnone/readonly/writeonly/...".
3419 getOrCreateAAFor<AAMemoryBehavior>(IRP: FPos);
3420
3421 // Every function can be "readnone/argmemonly/inaccessiblememonly/...".
3422 getOrCreateAAFor<AAMemoryLocation>(IRP: FPos);
3423
3424 // Every function can track active assumptions.
3425 getOrCreateAAFor<AAAssumptionInfo>(IRP: FPos);
3426
3427 // If we're not using a dynamic mode for float, there's nothing worthwhile
3428 // to infer. This misses the edge case denormal-fp-math="dynamic" and
3429 // denormal-fp-math-f32=something, but that likely has no real world use.
3430 DenormalMode Mode = F.getDenormalMode(FPType: APFloat::IEEEsingle());
3431 if (Mode.Input == DenormalMode::Dynamic ||
3432 Mode.Output == DenormalMode::Dynamic)
3433 getOrCreateAAFor<AADenormalFPMath>(IRP: FPos);
3434
3435 // Return attributes are only appropriate if the return type is non void.
3436 Type *ReturnType = F.getReturnType();
3437 if (!ReturnType->isVoidTy()) {
3438 IRPosition RetPos = IRPosition::returned(F);
3439 AttributeSet RetAttrs = Attrs.getRetAttrs();
3440
3441 // Every returned value might be dead.
3442 getOrCreateAAFor<AAIsDead>(IRP: RetPos);
3443
3444 // Every function might be simplified.
3445 bool UsedAssumedInformation = false;
3446 getAssumedSimplified(IRP: RetPos, AA: nullptr, UsedAssumedInformation,
3447 S: AA::Intraprocedural);
3448
3449 // Every returned value might be marked noundef.
3450 checkAndQueryIRAttr<Attribute::NoUndef, AANoUndef>(RetPos, RetAttrs);
3451
3452 if (ReturnType->isPointerTy()) {
3453
3454 // Every function with pointer return type might be marked align.
3455 getOrCreateAAFor<AAAlign>(IRP: RetPos);
3456
3457 // Every function with pointer return type might be marked nonnull.
3458 checkAndQueryIRAttr<Attribute::NonNull, AANonNull>(RetPos, RetAttrs);
3459
3460 // Every function with pointer return type might be marked noalias.
3461 checkAndQueryIRAttr<Attribute::NoAlias, AANoAlias>(RetPos, RetAttrs);
3462
3463 // Every function with pointer return type might be marked
3464 // dereferenceable.
3465 getOrCreateAAFor<AADereferenceable>(IRP: RetPos);
3466 } else if (AttributeFuncs::isNoFPClassCompatibleType(Ty: ReturnType)) {
3467 getOrCreateAAFor<AANoFPClass>(IRP: RetPos);
3468 }
3469 }
3470 }
3471
3472 for (Argument &Arg : F.args()) {
3473 IRPosition ArgPos = IRPosition::argument(Arg);
3474 auto ArgNo = Arg.getArgNo();
3475 AttributeSet ArgAttrs = Attrs.getParamAttrs(ArgNo);
3476
3477 if (!IsIPOAmendable) {
3478 if (Arg.getType()->isPointerTy())
3479 // Every argument with pointer type might be marked nofree.
3480 checkAndQueryIRAttr<Attribute::NoFree, AANoFree>(ArgPos, ArgAttrs);
3481 continue;
3482 }
3483
3484 // Every argument might be simplified. We have to go through the
3485 // Attributor interface though as outside AAs can register custom
3486 // simplification callbacks.
3487 bool UsedAssumedInformation = false;
3488 getAssumedSimplified(IRP: ArgPos, /* AA */ nullptr, UsedAssumedInformation,
3489 S: AA::Intraprocedural);
3490
3491 // Every argument might be dead.
3492 getOrCreateAAFor<AAIsDead>(IRP: ArgPos);
3493
3494 // Every argument might be marked noundef.
3495 checkAndQueryIRAttr<Attribute::NoUndef, AANoUndef>(ArgPos, ArgAttrs);
3496
3497 if (Arg.getType()->isPointerTy()) {
3498 // Every argument with pointer type might be marked nonnull.
3499 checkAndQueryIRAttr<Attribute::NonNull, AANonNull>(ArgPos, ArgAttrs);
3500
3501 // Every argument with pointer type might be marked noalias.
3502 checkAndQueryIRAttr<Attribute::NoAlias, AANoAlias>(ArgPos, ArgAttrs);
3503
3504 // Every argument with pointer type might be marked dereferenceable.
3505 getOrCreateAAFor<AADereferenceable>(IRP: ArgPos);
3506
3507 // Every argument with pointer type might be marked align.
3508 getOrCreateAAFor<AAAlign>(IRP: ArgPos);
3509
3510 // Every argument with pointer type might be marked nocapture.
3511 checkAndQueryIRAttr<Attribute::NoCapture, AANoCapture>(ArgPos, ArgAttrs);
3512
3513 // Every argument with pointer type might be marked
3514 // "readnone/readonly/writeonly/..."
3515 getOrCreateAAFor<AAMemoryBehavior>(IRP: ArgPos);
3516
3517 // Every argument with pointer type might be marked nofree.
3518 checkAndQueryIRAttr<Attribute::NoFree, AANoFree>(ArgPos, ArgAttrs);
3519
3520 // Every argument with pointer type might be privatizable (or
3521 // promotable)
3522 getOrCreateAAFor<AAPrivatizablePtr>(IRP: ArgPos);
3523 } else if (AttributeFuncs::isNoFPClassCompatibleType(Ty: Arg.getType())) {
3524 getOrCreateAAFor<AANoFPClass>(IRP: ArgPos);
3525 }
3526 }
3527
3528 auto CallSitePred = [&](Instruction &I) -> bool {
3529 auto &CB = cast<CallBase>(Val&: I);
3530 IRPosition CBInstPos = IRPosition::inst(I: CB);
3531 IRPosition CBFnPos = IRPosition::callsite_function(CB);
3532
3533 // Call sites might be dead if they do not have side effects and no live
3534 // users. The return value might be dead if there are no live users.
3535 getOrCreateAAFor<AAIsDead>(IRP: CBInstPos);
3536
3537 Function *Callee = dyn_cast_if_present<Function>(Val: CB.getCalledOperand());
3538 // TODO: Even if the callee is not known now we might be able to simplify
3539 // the call/callee.
3540 if (!Callee) {
3541 getOrCreateAAFor<AAIndirectCallInfo>(IRP: CBFnPos);
3542 return true;
3543 }
3544
3545 // Every call site can track active assumptions.
3546 getOrCreateAAFor<AAAssumptionInfo>(IRP: CBFnPos);
3547
3548 // Skip declarations except if annotations on their call sites were
3549 // explicitly requested.
3550 if (!AnnotateDeclarationCallSites && Callee->isDeclaration() &&
3551 !Callee->hasMetadata(KindID: LLVMContext::MD_callback))
3552 return true;
3553
3554 if (!Callee->getReturnType()->isVoidTy() && !CB.use_empty()) {
3555 IRPosition CBRetPos = IRPosition::callsite_returned(CB);
3556 bool UsedAssumedInformation = false;
3557 getAssumedSimplified(IRP: CBRetPos, AA: nullptr, UsedAssumedInformation,
3558 S: AA::Intraprocedural);
3559
3560 if (AttributeFuncs::isNoFPClassCompatibleType(Ty: Callee->getReturnType()))
3561 getOrCreateAAFor<AANoFPClass>(IRP: CBInstPos);
3562 }
3563
3564 const AttributeList &CBAttrs = CBFnPos.getAttrList();
3565 for (int I = 0, E = CB.arg_size(); I < E; ++I) {
3566
3567 IRPosition CBArgPos = IRPosition::callsite_argument(CB, ArgNo: I);
3568 AttributeSet CBArgAttrs = CBAttrs.getParamAttrs(ArgNo: I);
3569
3570 // Every call site argument might be dead.
3571 getOrCreateAAFor<AAIsDead>(IRP: CBArgPos);
3572
3573 // Call site argument might be simplified. We have to go through the
3574 // Attributor interface though as outside AAs can register custom
3575 // simplification callbacks.
3576 bool UsedAssumedInformation = false;
3577 getAssumedSimplified(IRP: CBArgPos, /* AA */ nullptr, UsedAssumedInformation,
3578 S: AA::Intraprocedural);
3579
3580 // Every call site argument might be marked "noundef".
3581 checkAndQueryIRAttr<Attribute::NoUndef, AANoUndef>(CBArgPos, CBArgAttrs);
3582
3583 Type *ArgTy = CB.getArgOperand(i: I)->getType();
3584
3585 if (!ArgTy->isPointerTy()) {
3586 if (AttributeFuncs::isNoFPClassCompatibleType(Ty: ArgTy))
3587 getOrCreateAAFor<AANoFPClass>(IRP: CBArgPos);
3588
3589 continue;
3590 }
3591
3592 // Call site argument attribute "non-null".
3593 checkAndQueryIRAttr<Attribute::NonNull, AANonNull>(CBArgPos, CBArgAttrs);
3594
3595 // Call site argument attribute "nocapture".
3596 checkAndQueryIRAttr<Attribute::NoCapture, AANoCapture>(CBArgPos,
3597 CBArgAttrs);
3598
3599 // Call site argument attribute "no-alias".
3600 checkAndQueryIRAttr<Attribute::NoAlias, AANoAlias>(CBArgPos, CBArgAttrs);
3601
3602 // Call site argument attribute "dereferenceable".
3603 getOrCreateAAFor<AADereferenceable>(IRP: CBArgPos);
3604
3605 // Call site argument attribute "align".
3606 getOrCreateAAFor<AAAlign>(IRP: CBArgPos);
3607
3608 // Call site argument attribute
3609 // "readnone/readonly/writeonly/..."
3610 if (!CBAttrs.hasParamAttr(I, Attribute::ReadNone))
3611 getOrCreateAAFor<AAMemoryBehavior>(IRP: CBArgPos);
3612
3613 // Call site argument attribute "nofree".
3614 checkAndQueryIRAttr<Attribute::NoFree, AANoFree>(CBArgPos, CBArgAttrs);
3615 }
3616 return true;
3617 };
3618
3619 auto &OpcodeInstMap = InfoCache.getOpcodeInstMapForFunction(F);
3620 [[maybe_unused]] bool Success;
3621 bool UsedAssumedInformation = false;
3622 Success = checkForAllInstructionsImpl(
3623 A: nullptr, OpcodeInstMap, Pred: CallSitePred, QueryingAA: nullptr, LivenessAA: nullptr,
3624 Opcodes: {(unsigned)Instruction::Invoke, (unsigned)Instruction::CallBr,
3625 (unsigned)Instruction::Call},
3626 UsedAssumedInformation);
3627 assert(Success && "Expected the check call to be successful!");
3628
3629 auto LoadStorePred = [&](Instruction &I) -> bool {
3630 if (auto *LI = dyn_cast<LoadInst>(Val: &I)) {
3631 getOrCreateAAFor<AAAlign>(IRP: IRPosition::value(V: *LI->getPointerOperand()));
3632 if (SimplifyAllLoads)
3633 getAssumedSimplified(IRP: IRPosition::value(V: I), AA: nullptr,
3634 UsedAssumedInformation, S: AA::Intraprocedural);
3635 getOrCreateAAFor<AAAddressSpace>(
3636 IRP: IRPosition::value(V: *LI->getPointerOperand()));
3637 } else {
3638 auto &SI = cast<StoreInst>(Val&: I);
3639 getOrCreateAAFor<AAIsDead>(IRP: IRPosition::inst(I));
3640 getAssumedSimplified(IRP: IRPosition::value(V: *SI.getValueOperand()), AA: nullptr,
3641 UsedAssumedInformation, S: AA::Intraprocedural);
3642 getOrCreateAAFor<AAAlign>(IRP: IRPosition::value(V: *SI.getPointerOperand()));
3643 getOrCreateAAFor<AAAddressSpace>(
3644 IRP: IRPosition::value(V: *SI.getPointerOperand()));
3645 }
3646 return true;
3647 };
3648 Success = checkForAllInstructionsImpl(
3649 A: nullptr, OpcodeInstMap, Pred: LoadStorePred, QueryingAA: nullptr, LivenessAA: nullptr,
3650 Opcodes: {(unsigned)Instruction::Load, (unsigned)Instruction::Store},
3651 UsedAssumedInformation);
3652 assert(Success && "Expected the check call to be successful!");
3653
3654 // AllocaInstPredicate
3655 auto AAAllocationInfoPred = [&](Instruction &I) -> bool {
3656 getOrCreateAAFor<AAAllocationInfo>(IRP: IRPosition::value(V: I));
3657 return true;
3658 };
3659
3660 Success = checkForAllInstructionsImpl(
3661 A: nullptr, OpcodeInstMap, Pred: AAAllocationInfoPred, QueryingAA: nullptr, LivenessAA: nullptr,
3662 Opcodes: {(unsigned)Instruction::Alloca}, UsedAssumedInformation);
3663 assert(Success && "Expected the check call to be successful!");
3664}
3665
3666bool Attributor::isClosedWorldModule() const {
3667 if (CloseWorldAssumption.getNumOccurrences())
3668 return CloseWorldAssumption;
3669 return isModulePass() && Configuration.IsClosedWorldModule;
3670}
3671
3672/// Helpers to ease debugging through output streams and print calls.
3673///
3674///{
3675raw_ostream &llvm::operator<<(raw_ostream &OS, ChangeStatus S) {
3676 return OS << (S == ChangeStatus::CHANGED ? "changed" : "unchanged");
3677}
3678
3679raw_ostream &llvm::operator<<(raw_ostream &OS, IRPosition::Kind AP) {
3680 switch (AP) {
3681 case IRPosition::IRP_INVALID:
3682 return OS << "inv";
3683 case IRPosition::IRP_FLOAT:
3684 return OS << "flt";
3685 case IRPosition::IRP_RETURNED:
3686 return OS << "fn_ret";
3687 case IRPosition::IRP_CALL_SITE_RETURNED:
3688 return OS << "cs_ret";
3689 case IRPosition::IRP_FUNCTION:
3690 return OS << "fn";
3691 case IRPosition::IRP_CALL_SITE:
3692 return OS << "cs";
3693 case IRPosition::IRP_ARGUMENT:
3694 return OS << "arg";
3695 case IRPosition::IRP_CALL_SITE_ARGUMENT:
3696 return OS << "cs_arg";
3697 }
3698 llvm_unreachable("Unknown attribute position!");
3699}
3700
3701raw_ostream &llvm::operator<<(raw_ostream &OS, const IRPosition &Pos) {
3702 const Value &AV = Pos.getAssociatedValue();
3703 OS << "{" << Pos.getPositionKind() << ":" << AV.getName() << " ["
3704 << Pos.getAnchorValue().getName() << "@" << Pos.getCallSiteArgNo() << "]";
3705
3706 if (Pos.hasCallBaseContext())
3707 OS << "[cb_context:" << *Pos.getCallBaseContext() << "]";
3708 return OS << "}";
3709}
3710
3711raw_ostream &llvm::operator<<(raw_ostream &OS, const IntegerRangeState &S) {
3712 OS << "range-state(" << S.getBitWidth() << ")<";
3713 S.getKnown().print(OS);
3714 OS << " / ";
3715 S.getAssumed().print(OS);
3716 OS << ">";
3717
3718 return OS << static_cast<const AbstractState &>(S);
3719}
3720
3721raw_ostream &llvm::operator<<(raw_ostream &OS, const AbstractState &S) {
3722 return OS << (!S.isValidState() ? "top" : (S.isAtFixpoint() ? "fix" : ""));
3723}
3724
3725raw_ostream &llvm::operator<<(raw_ostream &OS, const AbstractAttribute &AA) {
3726 AA.print(OS);
3727 return OS;
3728}
3729
3730raw_ostream &llvm::operator<<(raw_ostream &OS,
3731 const PotentialConstantIntValuesState &S) {
3732 OS << "set-state(< {";
3733 if (!S.isValidState())
3734 OS << "full-set";
3735 else {
3736 for (const auto &It : S.getAssumedSet())
3737 OS << It << ", ";
3738 if (S.undefIsContained())
3739 OS << "undef ";
3740 }
3741 OS << "} >)";
3742
3743 return OS;
3744}
3745
3746raw_ostream &llvm::operator<<(raw_ostream &OS,
3747 const PotentialLLVMValuesState &S) {
3748 OS << "set-state(< {";
3749 if (!S.isValidState())
3750 OS << "full-set";
3751 else {
3752 for (const auto &It : S.getAssumedSet()) {
3753 if (auto *F = dyn_cast<Function>(Val: It.first.getValue()))
3754 OS << "@" << F->getName() << "[" << int(It.second) << "], ";
3755 else
3756 OS << *It.first.getValue() << "[" << int(It.second) << "], ";
3757 }
3758 if (S.undefIsContained())
3759 OS << "undef ";
3760 }
3761 OS << "} >)";
3762
3763 return OS;
3764}
3765
3766void AbstractAttribute::print(Attributor *A, raw_ostream &OS) const {
3767 OS << "[";
3768 OS << getName();
3769 OS << "] for CtxI ";
3770
3771 if (auto *I = getCtxI()) {
3772 OS << "'";
3773 I->print(O&: OS);
3774 OS << "'";
3775 } else
3776 OS << "<<null inst>>";
3777
3778 OS << " at position " << getIRPosition() << " with state " << getAsStr(A)
3779 << '\n';
3780}
3781
3782void AbstractAttribute::printWithDeps(raw_ostream &OS) const {
3783 print(OS);
3784
3785 for (const auto &DepAA : Deps) {
3786 auto *AA = DepAA.getPointer();
3787 OS << " updates ";
3788 AA->print(OS);
3789 }
3790
3791 OS << '\n';
3792}
3793
3794raw_ostream &llvm::operator<<(raw_ostream &OS,
3795 const AAPointerInfo::Access &Acc) {
3796 OS << " [" << Acc.getKind() << "] " << *Acc.getRemoteInst();
3797 if (Acc.getLocalInst() != Acc.getRemoteInst())
3798 OS << " via " << *Acc.getLocalInst();
3799 if (Acc.getContent()) {
3800 if (*Acc.getContent())
3801 OS << " [" << **Acc.getContent() << "]";
3802 else
3803 OS << " [ <unknown> ]";
3804 }
3805 return OS;
3806}
3807///}
3808
3809/// ----------------------------------------------------------------------------
3810/// Pass (Manager) Boilerplate
3811/// ----------------------------------------------------------------------------
3812
3813static bool runAttributorOnFunctions(InformationCache &InfoCache,
3814 SetVector<Function *> &Functions,
3815 AnalysisGetter &AG,
3816 CallGraphUpdater &CGUpdater,
3817 bool DeleteFns, bool IsModulePass) {
3818 if (Functions.empty())
3819 return false;
3820
3821 LLVM_DEBUG({
3822 dbgs() << "[Attributor] Run on module with " << Functions.size()
3823 << " functions:\n";
3824 for (Function *Fn : Functions)
3825 dbgs() << " - " << Fn->getName() << "\n";
3826 });
3827
3828 // Create an Attributor and initially empty information cache that is filled
3829 // while we identify default attribute opportunities.
3830 AttributorConfig AC(CGUpdater);
3831 AC.IsModulePass = IsModulePass;
3832 AC.DeleteFns = DeleteFns;
3833
3834 /// Tracking callback for specialization of indirect calls.
3835 DenseMap<CallBase *, std::unique_ptr<SmallPtrSet<Function *, 8>>>
3836 IndirectCalleeTrackingMap;
3837 if (MaxSpecializationPerCB.getNumOccurrences()) {
3838 AC.IndirectCalleeSpecializationCallback =
3839 [&](Attributor &, const AbstractAttribute &AA, CallBase &CB,
3840 Function &Callee) {
3841 if (MaxSpecializationPerCB == 0)
3842 return false;
3843 auto &Set = IndirectCalleeTrackingMap[&CB];
3844 if (!Set)
3845 Set = std::make_unique<SmallPtrSet<Function *, 8>>();
3846 if (Set->size() >= MaxSpecializationPerCB)
3847 return Set->contains(Ptr: &Callee);
3848 Set->insert(Ptr: &Callee);
3849 return true;
3850 };
3851 }
3852
3853 Attributor A(Functions, InfoCache, AC);
3854
3855 // Create shallow wrappers for all functions that are not IPO amendable
3856 if (AllowShallowWrappers)
3857 for (Function *F : Functions)
3858 if (!A.isFunctionIPOAmendable(F: *F))
3859 Attributor::createShallowWrapper(F&: *F);
3860
3861 // Internalize non-exact functions
3862 // TODO: for now we eagerly internalize functions without calculating the
3863 // cost, we need a cost interface to determine whether internalizing
3864 // a function is "beneficial"
3865 if (AllowDeepWrapper) {
3866 unsigned FunSize = Functions.size();
3867 for (unsigned u = 0; u < FunSize; u++) {
3868 Function *F = Functions[u];
3869 if (!F->isDeclaration() && !F->isDefinitionExact() && F->getNumUses() &&
3870 !GlobalValue::isInterposableLinkage(Linkage: F->getLinkage())) {
3871 Function *NewF = Attributor::internalizeFunction(F&: *F);
3872 assert(NewF && "Could not internalize function.");
3873 Functions.insert(X: NewF);
3874
3875 // Update call graph
3876 CGUpdater.replaceFunctionWith(OldFn&: *F, NewFn&: *NewF);
3877 for (const Use &U : NewF->uses())
3878 if (CallBase *CB = dyn_cast<CallBase>(Val: U.getUser())) {
3879 auto *CallerF = CB->getCaller();
3880 CGUpdater.reanalyzeFunction(Fn&: *CallerF);
3881 }
3882 }
3883 }
3884 }
3885
3886 for (Function *F : Functions) {
3887 if (F->hasExactDefinition())
3888 NumFnWithExactDefinition++;
3889 else
3890 NumFnWithoutExactDefinition++;
3891
3892 // We look at internal functions only on-demand but if any use is not a
3893 // direct call or outside the current set of analyzed functions, we have
3894 // to do it eagerly.
3895 if (F->hasLocalLinkage()) {
3896 if (llvm::all_of(Range: F->uses(), P: [&Functions](const Use &U) {
3897 const auto *CB = dyn_cast<CallBase>(Val: U.getUser());
3898 return CB && CB->isCallee(U: &U) &&
3899 Functions.count(key: const_cast<Function *>(CB->getCaller()));
3900 }))
3901 continue;
3902 }
3903
3904 // Populate the Attributor with abstract attribute opportunities in the
3905 // function and the information cache with IR information.
3906 A.identifyDefaultAbstractAttributes(F&: *F);
3907 }
3908
3909 ChangeStatus Changed = A.run();
3910
3911 LLVM_DEBUG(dbgs() << "[Attributor] Done with " << Functions.size()
3912 << " functions, result: " << Changed << ".\n");
3913 return Changed == ChangeStatus::CHANGED;
3914}
3915
3916static bool runAttributorLightOnFunctions(InformationCache &InfoCache,
3917 SetVector<Function *> &Functions,
3918 AnalysisGetter &AG,
3919 CallGraphUpdater &CGUpdater,
3920 FunctionAnalysisManager &FAM,
3921 bool IsModulePass) {
3922 if (Functions.empty())
3923 return false;
3924
3925 LLVM_DEBUG({
3926 dbgs() << "[AttributorLight] Run on module with " << Functions.size()
3927 << " functions:\n";
3928 for (Function *Fn : Functions)
3929 dbgs() << " - " << Fn->getName() << "\n";
3930 });
3931
3932 // Create an Attributor and initially empty information cache that is filled
3933 // while we identify default attribute opportunities.
3934 AttributorConfig AC(CGUpdater);
3935 AC.IsModulePass = IsModulePass;
3936 AC.DeleteFns = false;
3937 DenseSet<const char *> Allowed(
3938 {&AAWillReturn::ID, &AANoUnwind::ID, &AANoRecurse::ID, &AANoSync::ID,
3939 &AANoFree::ID, &AANoReturn::ID, &AAMemoryLocation::ID,
3940 &AAMemoryBehavior::ID, &AAUnderlyingObjects::ID, &AANoCapture::ID,
3941 &AAInterFnReachability::ID, &AAIntraFnReachability::ID, &AACallEdges::ID,
3942 &AANoFPClass::ID, &AAMustProgress::ID, &AANonNull::ID});
3943 AC.Allowed = &Allowed;
3944 AC.UseLiveness = false;
3945
3946 Attributor A(Functions, InfoCache, AC);
3947
3948 for (Function *F : Functions) {
3949 if (F->hasExactDefinition())
3950 NumFnWithExactDefinition++;
3951 else
3952 NumFnWithoutExactDefinition++;
3953
3954 // We look at internal functions only on-demand but if any use is not a
3955 // direct call or outside the current set of analyzed functions, we have
3956 // to do it eagerly.
3957 if (F->hasLocalLinkage()) {
3958 if (llvm::all_of(Range: F->uses(), P: [&Functions](const Use &U) {
3959 const auto *CB = dyn_cast<CallBase>(Val: U.getUser());
3960 return CB && CB->isCallee(U: &U) &&
3961 Functions.count(key: const_cast<Function *>(CB->getCaller()));
3962 }))
3963 continue;
3964 }
3965
3966 // Populate the Attributor with abstract attribute opportunities in the
3967 // function and the information cache with IR information.
3968 A.identifyDefaultAbstractAttributes(F&: *F);
3969 }
3970
3971 ChangeStatus Changed = A.run();
3972
3973 if (Changed == ChangeStatus::CHANGED) {
3974 // Invalidate analyses for modified functions so that we don't have to
3975 // invalidate all analyses for all functions in this SCC.
3976 PreservedAnalyses FuncPA;
3977 // We haven't changed the CFG for modified functions.
3978 FuncPA.preserveSet<CFGAnalyses>();
3979 for (Function *Changed : A.getModifiedFunctions()) {
3980 FAM.invalidate(IR&: *Changed, PA: FuncPA);
3981 // Also invalidate any direct callers of changed functions since analyses
3982 // may care about attributes of direct callees. For example, MemorySSA
3983 // cares about whether or not a call's callee modifies memory and queries
3984 // that through function attributes.
3985 for (auto *U : Changed->users()) {
3986 if (auto *Call = dyn_cast<CallBase>(Val: U)) {
3987 if (Call->getCalledFunction() == Changed)
3988 FAM.invalidate(IR&: *Call->getFunction(), PA: FuncPA);
3989 }
3990 }
3991 }
3992 }
3993 LLVM_DEBUG(dbgs() << "[Attributor] Done with " << Functions.size()
3994 << " functions, result: " << Changed << ".\n");
3995 return Changed == ChangeStatus::CHANGED;
3996}
3997
3998void AADepGraph::viewGraph() { llvm::ViewGraph(G: this, Name: "Dependency Graph"); }
3999
4000void AADepGraph::dumpGraph() {
4001 static std::atomic<int> CallTimes;
4002 std::string Prefix;
4003
4004 if (!DepGraphDotFileNamePrefix.empty())
4005 Prefix = DepGraphDotFileNamePrefix;
4006 else
4007 Prefix = "dep_graph";
4008 std::string Filename =
4009 Prefix + "_" + std::to_string(val: CallTimes.load()) + ".dot";
4010
4011 outs() << "Dependency graph dump to " << Filename << ".\n";
4012
4013 std::error_code EC;
4014
4015 raw_fd_ostream File(Filename, EC, sys::fs::OF_TextWithCRLF);
4016 if (!EC)
4017 llvm::WriteGraph(O&: File, G: this);
4018
4019 CallTimes++;
4020}
4021
4022void AADepGraph::print() {
4023 for (auto DepAA : SyntheticRoot.Deps)
4024 cast<AbstractAttribute>(Val: DepAA.getPointer())->printWithDeps(OS&: outs());
4025}
4026
4027PreservedAnalyses AttributorPass::run(Module &M, ModuleAnalysisManager &AM) {
4028 FunctionAnalysisManager &FAM =
4029 AM.getResult<FunctionAnalysisManagerModuleProxy>(IR&: M).getManager();
4030 AnalysisGetter AG(FAM);
4031
4032 SetVector<Function *> Functions;
4033 for (Function &F : M)
4034 Functions.insert(X: &F);
4035
4036 CallGraphUpdater CGUpdater;
4037 BumpPtrAllocator Allocator;
4038 InformationCache InfoCache(M, AG, Allocator, /* CGSCC */ nullptr);
4039 if (runAttributorOnFunctions(InfoCache, Functions, AG, CGUpdater,
4040 /* DeleteFns */ true, /* IsModulePass */ true)) {
4041 // FIXME: Think about passes we will preserve and add them here.
4042 return PreservedAnalyses::none();
4043 }
4044 return PreservedAnalyses::all();
4045}
4046
4047PreservedAnalyses AttributorCGSCCPass::run(LazyCallGraph::SCC &C,
4048 CGSCCAnalysisManager &AM,
4049 LazyCallGraph &CG,
4050 CGSCCUpdateResult &UR) {
4051 FunctionAnalysisManager &FAM =
4052 AM.getResult<FunctionAnalysisManagerCGSCCProxy>(IR&: C, ExtraArgs&: CG).getManager();
4053 AnalysisGetter AG(FAM);
4054
4055 SetVector<Function *> Functions;
4056 for (LazyCallGraph::Node &N : C)
4057 Functions.insert(X: &N.getFunction());
4058
4059 if (Functions.empty())
4060 return PreservedAnalyses::all();
4061
4062 Module &M = *Functions.back()->getParent();
4063 CallGraphUpdater CGUpdater;
4064 CGUpdater.initialize(LCG&: CG, SCC&: C, AM, UR);
4065 BumpPtrAllocator Allocator;
4066 InformationCache InfoCache(M, AG, Allocator, /* CGSCC */ &Functions);
4067 if (runAttributorOnFunctions(InfoCache, Functions, AG, CGUpdater,
4068 /* DeleteFns */ false,
4069 /* IsModulePass */ false)) {
4070 // FIXME: Think about passes we will preserve and add them here.
4071 PreservedAnalyses PA;
4072 PA.preserve<FunctionAnalysisManagerCGSCCProxy>();
4073 return PA;
4074 }
4075 return PreservedAnalyses::all();
4076}
4077
4078PreservedAnalyses AttributorLightPass::run(Module &M,
4079 ModuleAnalysisManager &AM) {
4080 FunctionAnalysisManager &FAM =
4081 AM.getResult<FunctionAnalysisManagerModuleProxy>(IR&: M).getManager();
4082 AnalysisGetter AG(FAM, /* CachedOnly */ true);
4083
4084 SetVector<Function *> Functions;
4085 for (Function &F : M)
4086 Functions.insert(X: &F);
4087
4088 CallGraphUpdater CGUpdater;
4089 BumpPtrAllocator Allocator;
4090 InformationCache InfoCache(M, AG, Allocator, /* CGSCC */ nullptr);
4091 if (runAttributorLightOnFunctions(InfoCache, Functions, AG, CGUpdater, FAM,
4092 /* IsModulePass */ true)) {
4093 PreservedAnalyses PA;
4094 // We have not added or removed functions.
4095 PA.preserve<FunctionAnalysisManagerCGSCCProxy>();
4096 // We already invalidated all relevant function analyses above.
4097 PA.preserveSet<AllAnalysesOn<Function>>();
4098 return PA;
4099 }
4100 return PreservedAnalyses::all();
4101}
4102
4103PreservedAnalyses AttributorLightCGSCCPass::run(LazyCallGraph::SCC &C,
4104 CGSCCAnalysisManager &AM,
4105 LazyCallGraph &CG,
4106 CGSCCUpdateResult &UR) {
4107 FunctionAnalysisManager &FAM =
4108 AM.getResult<FunctionAnalysisManagerCGSCCProxy>(IR&: C, ExtraArgs&: CG).getManager();
4109 AnalysisGetter AG(FAM);
4110
4111 SetVector<Function *> Functions;
4112 for (LazyCallGraph::Node &N : C)
4113 Functions.insert(X: &N.getFunction());
4114
4115 if (Functions.empty())
4116 return PreservedAnalyses::all();
4117
4118 Module &M = *Functions.back()->getParent();
4119 CallGraphUpdater CGUpdater;
4120 CGUpdater.initialize(LCG&: CG, SCC&: C, AM, UR);
4121 BumpPtrAllocator Allocator;
4122 InformationCache InfoCache(M, AG, Allocator, /* CGSCC */ &Functions);
4123 if (runAttributorLightOnFunctions(InfoCache, Functions, AG, CGUpdater, FAM,
4124 /* IsModulePass */ false)) {
4125 PreservedAnalyses PA;
4126 // We have not added or removed functions.
4127 PA.preserve<FunctionAnalysisManagerCGSCCProxy>();
4128 // We already invalidated all relevant function analyses above.
4129 PA.preserveSet<AllAnalysesOn<Function>>();
4130 return PA;
4131 }
4132 return PreservedAnalyses::all();
4133}
4134namespace llvm {
4135
4136template <> struct GraphTraits<AADepGraphNode *> {
4137 using NodeRef = AADepGraphNode *;
4138 using DepTy = PointerIntPair<AADepGraphNode *, 1>;
4139 using EdgeRef = PointerIntPair<AADepGraphNode *, 1>;
4140
4141 static NodeRef getEntryNode(AADepGraphNode *DGN) { return DGN; }
4142 static NodeRef DepGetVal(const DepTy &DT) { return DT.getPointer(); }
4143
4144 using ChildIteratorType =
4145 mapped_iterator<AADepGraphNode::DepSetTy::iterator, decltype(&DepGetVal)>;
4146 using ChildEdgeIteratorType = AADepGraphNode::DepSetTy::iterator;
4147
4148 static ChildIteratorType child_begin(NodeRef N) { return N->child_begin(); }
4149
4150 static ChildIteratorType child_end(NodeRef N) { return N->child_end(); }
4151};
4152
4153template <>
4154struct GraphTraits<AADepGraph *> : public GraphTraits<AADepGraphNode *> {
4155 static NodeRef getEntryNode(AADepGraph *DG) { return DG->GetEntryNode(); }
4156
4157 using nodes_iterator =
4158 mapped_iterator<AADepGraphNode::DepSetTy::iterator, decltype(&DepGetVal)>;
4159
4160 static nodes_iterator nodes_begin(AADepGraph *DG) { return DG->begin(); }
4161
4162 static nodes_iterator nodes_end(AADepGraph *DG) { return DG->end(); }
4163};
4164
4165template <> struct DOTGraphTraits<AADepGraph *> : public DefaultDOTGraphTraits {
4166 DOTGraphTraits(bool isSimple = false) : DefaultDOTGraphTraits(isSimple) {}
4167
4168 static std::string getNodeLabel(const AADepGraphNode *Node,
4169 const AADepGraph *DG) {
4170 std::string AAString;
4171 raw_string_ostream O(AAString);
4172 Node->print(OS&: O);
4173 return AAString;
4174 }
4175};
4176
4177} // end namespace llvm
4178

source code of llvm/lib/Transforms/IPO/Attributor.cpp