1 //===- ValueMapper.cpp - Interface shared by lib/Transforms/Utils ---------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines the MapValue function, which is shared by various parts of
11 // the lib/Transforms/Utils library.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Transforms/Utils/ValueMapper.h"
16 #include "llvm/IR/CallSite.h"
17 #include "llvm/IR/Constants.h"
18 #include "llvm/IR/Function.h"
19 #include "llvm/IR/InlineAsm.h"
20 #include "llvm/IR/Instructions.h"
21 #include "llvm/IR/Metadata.h"
22 #include "llvm/IR/Operator.h"
25 // Out of line method to get vtable etc for class.
26 void ValueMapTypeRemapper::anchor() {}
27 void ValueMaterializer::anchor() {}
28 void ValueMaterializer::materializeInitFor(GlobalValue *New, GlobalValue *Old) {
31 Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM, RemapFlags Flags,
32 ValueMapTypeRemapper *TypeMapper,
33 ValueMaterializer *Materializer) {
34 ValueToValueMapTy::iterator I = VM.find(V);
36 // If the value already exists in the map, use it.
37 if (I != VM.end() && I->second) return I->second;
39 // If we have a materializer and it can materialize a value, use that.
42 Materializer->materializeDeclFor(const_cast<Value *>(V))) {
44 if (auto *NewGV = dyn_cast<GlobalValue>(NewV))
45 Materializer->materializeInitFor(
46 NewGV, const_cast<GlobalValue *>(cast<GlobalValue>(V)));
51 // Global values do not need to be seeded into the VM if they
52 // are using the identity mapping.
53 if (isa<GlobalValue>(V)) {
54 if (Flags & RF_NullMapMissingGlobalValues) {
55 assert(!(Flags & RF_IgnoreMissingEntries) &&
56 "Illegal to specify both RF_NullMapMissingGlobalValues and "
57 "RF_IgnoreMissingEntries");
60 return VM[V] = const_cast<Value*>(V);
63 if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
64 // Inline asm may need *type* remapping.
65 FunctionType *NewTy = IA->getFunctionType();
67 NewTy = cast<FunctionType>(TypeMapper->remapType(NewTy));
69 if (NewTy != IA->getFunctionType())
70 V = InlineAsm::get(NewTy, IA->getAsmString(), IA->getConstraintString(),
71 IA->hasSideEffects(), IA->isAlignStack());
74 return VM[V] = const_cast<Value*>(V);
77 if (const auto *MDV = dyn_cast<MetadataAsValue>(V)) {
78 const Metadata *MD = MDV->getMetadata();
79 // If this is a module-level metadata and we know that nothing at the module
80 // level is changing, then use an identity mapping.
81 if (!isa<LocalAsMetadata>(MD) && (Flags & RF_NoModuleLevelChanges))
82 return VM[V] = const_cast<Value *>(V);
84 auto *MappedMD = MapMetadata(MD, VM, Flags, TypeMapper, Materializer);
85 if (MD == MappedMD || (!MappedMD && (Flags & RF_IgnoreMissingEntries)))
86 return VM[V] = const_cast<Value *>(V);
88 // FIXME: This assert crashes during bootstrap, but I think it should be
89 // correct. For now, just match behaviour from before the metadata/value
92 // assert((MappedMD || (Flags & RF_NullMapMissingGlobalValues)) &&
93 // "Referenced metadata value not in value map");
94 return VM[V] = MetadataAsValue::get(V->getContext(), MappedMD);
97 // Okay, this either must be a constant (which may or may not be mappable) or
98 // is something that is not in the mapping table.
99 Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V));
103 if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
105 cast<Function>(MapValue(BA->getFunction(), VM, Flags, TypeMapper, Materializer));
106 BasicBlock *BB = cast_or_null<BasicBlock>(MapValue(BA->getBasicBlock(), VM,
107 Flags, TypeMapper, Materializer));
108 return VM[V] = BlockAddress::get(F, BB ? BB : BA->getBasicBlock());
111 // Otherwise, we have some other constant to remap. Start by checking to see
112 // if all operands have an identity remapping.
113 unsigned OpNo = 0, NumOperands = C->getNumOperands();
114 Value *Mapped = nullptr;
115 for (; OpNo != NumOperands; ++OpNo) {
116 Value *Op = C->getOperand(OpNo);
117 Mapped = MapValue(Op, VM, Flags, TypeMapper, Materializer);
118 if (Mapped != C) break;
121 // See if the type mapper wants to remap the type as well.
122 Type *NewTy = C->getType();
124 NewTy = TypeMapper->remapType(NewTy);
126 // If the result type and all operands match up, then just insert an identity
128 if (OpNo == NumOperands && NewTy == C->getType())
131 // Okay, we need to create a new constant. We've already processed some or
132 // all of the operands, set them all up now.
133 SmallVector<Constant*, 8> Ops;
134 Ops.reserve(NumOperands);
135 for (unsigned j = 0; j != OpNo; ++j)
136 Ops.push_back(cast<Constant>(C->getOperand(j)));
138 // If one of the operands mismatch, push it and the other mapped operands.
139 if (OpNo != NumOperands) {
140 Ops.push_back(cast<Constant>(Mapped));
142 // Map the rest of the operands that aren't processed yet.
143 for (++OpNo; OpNo != NumOperands; ++OpNo)
144 Ops.push_back(MapValue(cast<Constant>(C->getOperand(OpNo)), VM,
145 Flags, TypeMapper, Materializer));
147 Type *NewSrcTy = nullptr;
149 if (auto *GEPO = dyn_cast<GEPOperator>(C))
150 NewSrcTy = TypeMapper->remapType(GEPO->getSourceElementType());
152 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
153 return VM[V] = CE->getWithOperands(Ops, NewTy, false, NewSrcTy);
154 if (isa<ConstantArray>(C))
155 return VM[V] = ConstantArray::get(cast<ArrayType>(NewTy), Ops);
156 if (isa<ConstantStruct>(C))
157 return VM[V] = ConstantStruct::get(cast<StructType>(NewTy), Ops);
158 if (isa<ConstantVector>(C))
159 return VM[V] = ConstantVector::get(Ops);
160 // If this is a no-operand constant, it must be because the type was remapped.
161 if (isa<UndefValue>(C))
162 return VM[V] = UndefValue::get(NewTy);
163 if (isa<ConstantAggregateZero>(C))
164 return VM[V] = ConstantAggregateZero::get(NewTy);
165 assert(isa<ConstantPointerNull>(C));
166 return VM[V] = ConstantPointerNull::get(cast<PointerType>(NewTy));
169 static Metadata *mapToMetadata(ValueToValueMapTy &VM, const Metadata *Key,
171 VM.MD()[Key].reset(Val);
175 static Metadata *mapToSelf(ValueToValueMapTy &VM, const Metadata *MD) {
176 return mapToMetadata(VM, MD, const_cast<Metadata *>(MD));
179 static Metadata *MapMetadataImpl(const Metadata *MD,
180 SmallVectorImpl<MDNode *> &DistinctWorklist,
181 ValueToValueMapTy &VM, RemapFlags Flags,
182 ValueMapTypeRemapper *TypeMapper,
183 ValueMaterializer *Materializer);
185 static Metadata *mapMetadataOp(Metadata *Op,
186 SmallVectorImpl<MDNode *> &DistinctWorklist,
187 ValueToValueMapTy &VM, RemapFlags Flags,
188 ValueMapTypeRemapper *TypeMapper,
189 ValueMaterializer *Materializer) {
192 if (Metadata *MappedOp = MapMetadataImpl(Op, DistinctWorklist, VM, Flags,
193 TypeMapper, Materializer))
195 // Use identity map if MappedOp is null and we can ignore missing entries.
196 if (Flags & RF_IgnoreMissingEntries)
199 // FIXME: This assert crashes during bootstrap, but I think it should be
200 // correct. For now, just match behaviour from before the metadata/value
203 // assert((Flags & RF_NullMapMissingGlobalValues) &&
204 // "Referenced metadata not in value map!");
208 /// Resolve uniquing cycles involving the given metadata.
209 static void resolveCycles(Metadata *MD) {
210 if (auto *N = dyn_cast_or_null<MDNode>(MD))
211 if (!N->isResolved())
215 /// Remap the operands of an MDNode.
217 /// If \c Node is temporary, uniquing cycles are ignored. If \c Node is
218 /// distinct, uniquing cycles are resolved as they're found.
220 /// \pre \c Node.isDistinct() or \c Node.isTemporary().
221 static bool remapOperands(MDNode &Node,
222 SmallVectorImpl<MDNode *> &DistinctWorklist,
223 ValueToValueMapTy &VM, RemapFlags Flags,
224 ValueMapTypeRemapper *TypeMapper,
225 ValueMaterializer *Materializer) {
226 assert(!Node.isUniqued() && "Expected temporary or distinct node");
227 const bool IsDistinct = Node.isDistinct();
229 bool AnyChanged = false;
230 for (unsigned I = 0, E = Node.getNumOperands(); I != E; ++I) {
231 Metadata *Old = Node.getOperand(I);
232 Metadata *New = mapMetadataOp(Old, DistinctWorklist, VM, Flags, TypeMapper,
236 Node.replaceOperandWith(I, New);
238 // Resolve uniquing cycles underneath distinct nodes on the fly so they
239 // don't infect later operands.
248 /// Map a distinct MDNode.
250 /// Whether distinct nodes change is independent of their operands. If \a
251 /// RF_MoveDistinctMDs, then they are reused, and their operands remapped in
252 /// place; effectively, they're moved from one graph to another. Otherwise,
253 /// they're cloned/duplicated, and the new copy's operands are remapped.
254 static Metadata *mapDistinctNode(const MDNode *Node,
255 SmallVectorImpl<MDNode *> &DistinctWorklist,
256 ValueToValueMapTy &VM, RemapFlags Flags,
257 ValueMapTypeRemapper *TypeMapper,
258 ValueMaterializer *Materializer) {
259 assert(Node->isDistinct() && "Expected distinct node");
262 if (Flags & RF_MoveDistinctMDs)
263 NewMD = const_cast<MDNode *>(Node);
265 NewMD = MDNode::replaceWithDistinct(Node->clone());
267 // Remap operands later.
268 DistinctWorklist.push_back(NewMD);
269 return mapToMetadata(VM, Node, NewMD);
272 /// \brief Map a uniqued MDNode.
274 /// Uniqued nodes may not need to be recreated (they may map to themselves).
275 static Metadata *mapUniquedNode(const MDNode *Node,
276 SmallVectorImpl<MDNode *> &DistinctWorklist,
277 ValueToValueMapTy &VM, RemapFlags Flags,
278 ValueMapTypeRemapper *TypeMapper,
279 ValueMaterializer *Materializer) {
280 assert(Node->isUniqued() && "Expected uniqued node");
282 // Create a temporary node and map it upfront in case we have a uniquing
283 // cycle. If necessary, this mapping will get updated by RAUW logic before
285 auto ClonedMD = Node->clone();
286 mapToMetadata(VM, Node, ClonedMD.get());
287 if (!remapOperands(*ClonedMD, DistinctWorklist, VM, Flags, TypeMapper,
289 // No operands changed, so use the original.
290 ClonedMD->replaceAllUsesWith(const_cast<MDNode *>(Node));
291 return const_cast<MDNode *>(Node);
294 // Uniquify the cloned node.
295 return MDNode::replaceWithUniqued(std::move(ClonedMD));
298 static Metadata *MapMetadataImpl(const Metadata *MD,
299 SmallVectorImpl<MDNode *> &DistinctWorklist,
300 ValueToValueMapTy &VM, RemapFlags Flags,
301 ValueMapTypeRemapper *TypeMapper,
302 ValueMaterializer *Materializer) {
303 // If the value already exists in the map, use it.
304 if (Metadata *NewMD = VM.MD().lookup(MD).get())
307 if (isa<MDString>(MD))
308 return mapToSelf(VM, MD);
310 if (isa<ConstantAsMetadata>(MD))
311 if ((Flags & RF_NoModuleLevelChanges))
312 return mapToSelf(VM, MD);
314 if (const auto *VMD = dyn_cast<ValueAsMetadata>(MD)) {
316 MapValue(VMD->getValue(), VM, Flags, TypeMapper, Materializer);
317 if (VMD->getValue() == MappedV ||
318 (!MappedV && (Flags & RF_IgnoreMissingEntries)))
319 return mapToSelf(VM, MD);
321 // FIXME: This assert crashes during bootstrap, but I think it should be
322 // correct. For now, just match behaviour from before the metadata/value
325 // assert((MappedV || (Flags & RF_NullMapMissingGlobalValues)) &&
326 // "Referenced metadata not in value map!");
328 return mapToMetadata(VM, MD, ValueAsMetadata::get(MappedV));
332 // Note: this cast precedes the Flags check so we always get its associated
334 const MDNode *Node = cast<MDNode>(MD);
336 // If this is a module-level metadata and we know that nothing at the
337 // module level is changing, then use an identity mapping.
338 if (Flags & RF_NoModuleLevelChanges)
339 return mapToSelf(VM, MD);
341 // Require resolved nodes whenever metadata might be remapped.
342 assert(Node->isResolved() && "Unexpected unresolved node");
344 if (Node->isDistinct())
345 return mapDistinctNode(Node, DistinctWorklist, VM, Flags, TypeMapper,
348 return mapUniquedNode(Node, DistinctWorklist, VM, Flags, TypeMapper,
352 Metadata *llvm::MapMetadata(const Metadata *MD, ValueToValueMapTy &VM,
353 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
354 ValueMaterializer *Materializer) {
355 SmallVector<MDNode *, 8> DistinctWorklist;
356 Metadata *NewMD = MapMetadataImpl(MD, DistinctWorklist, VM, Flags, TypeMapper,
359 // When there are no module-level changes, it's possible that the metadata
360 // graph has temporaries. Skip the logic to resolve cycles, since it's
361 // unnecessary (and invalid) in that case.
362 if (Flags & RF_NoModuleLevelChanges)
365 // Resolve cycles involving the entry metadata.
366 resolveCycles(NewMD);
368 // Remap the operands of distinct MDNodes.
369 while (!DistinctWorklist.empty())
370 remapOperands(*DistinctWorklist.pop_back_val(), DistinctWorklist, VM, Flags,
371 TypeMapper, Materializer);
376 MDNode *llvm::MapMetadata(const MDNode *MD, ValueToValueMapTy &VM,
377 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
378 ValueMaterializer *Materializer) {
379 return cast<MDNode>(MapMetadata(static_cast<const Metadata *>(MD), VM, Flags,
380 TypeMapper, Materializer));
383 /// RemapInstruction - Convert the instruction operands from referencing the
384 /// current values into those specified by VMap.
386 void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
387 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
388 ValueMaterializer *Materializer){
390 for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
391 Value *V = MapValue(*op, VMap, Flags, TypeMapper, Materializer);
392 // If we aren't ignoring missing entries, assert that something happened.
396 assert((Flags & RF_IgnoreMissingEntries) &&
397 "Referenced value not in value map!");
400 // Remap phi nodes' incoming blocks.
401 if (PHINode *PN = dyn_cast<PHINode>(I)) {
402 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
403 Value *V = MapValue(PN->getIncomingBlock(i), VMap, Flags);
404 // If we aren't ignoring missing entries, assert that something happened.
406 PN->setIncomingBlock(i, cast<BasicBlock>(V));
408 assert((Flags & RF_IgnoreMissingEntries) &&
409 "Referenced block not in value map!");
413 // Remap attached metadata.
414 SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
415 I->getAllMetadata(MDs);
416 for (const auto &MI : MDs) {
417 MDNode *Old = MI.second;
418 MDNode *New = MapMetadata(Old, VMap, Flags, TypeMapper, Materializer);
420 I->setMetadata(MI.first, New);
426 // If the instruction's type is being remapped, do so now.
427 if (auto CS = CallSite(I)) {
428 SmallVector<Type *, 3> Tys;
429 FunctionType *FTy = CS.getFunctionType();
430 Tys.reserve(FTy->getNumParams());
431 for (Type *Ty : FTy->params())
432 Tys.push_back(TypeMapper->remapType(Ty));
433 CS.mutateFunctionType(FunctionType::get(
434 TypeMapper->remapType(I->getType()), Tys, FTy->isVarArg()));
437 if (auto *AI = dyn_cast<AllocaInst>(I))
438 AI->setAllocatedType(TypeMapper->remapType(AI->getAllocatedType()));
439 if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) {
440 GEP->setSourceElementType(
441 TypeMapper->remapType(GEP->getSourceElementType()));
442 GEP->setResultElementType(
443 TypeMapper->remapType(GEP->getResultElementType()));
445 I->mutateType(TypeMapper->remapType(I->getType()));