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"
24 // Out of line method to get vtable etc for class.
25 void ValueMapTypeRemapper::anchor() {}
26 void ValueMaterializer::anchor() {}
28 Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM, RemapFlags Flags,
29 ValueMapTypeRemapper *TypeMapper,
30 ValueMaterializer *Materializer) {
31 ValueToValueMapTy::iterator I = VM.find(V);
33 // If the value already exists in the map, use it.
34 if (I != VM.end() && I->second) return I->second;
36 // If we have a materializer and it can materialize a value, use that.
38 if (Value *NewV = Materializer->materializeValueFor(const_cast<Value*>(V)))
42 // Global values do not need to be seeded into the VM if they
43 // are using the identity mapping.
44 if (isa<GlobalValue>(V))
45 return VM[V] = const_cast<Value*>(V);
47 if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
48 // Inline asm may need *type* remapping.
49 FunctionType *NewTy = IA->getFunctionType();
51 NewTy = cast<FunctionType>(TypeMapper->remapType(NewTy));
53 if (NewTy != IA->getFunctionType())
54 V = InlineAsm::get(NewTy, IA->getAsmString(), IA->getConstraintString(),
55 IA->hasSideEffects(), IA->isAlignStack());
58 return VM[V] = const_cast<Value*>(V);
61 if (const auto *MDV = dyn_cast<MetadataAsValue>(V)) {
62 const Metadata *MD = MDV->getMetadata();
63 // If this is a module-level metadata and we know that nothing at the module
64 // level is changing, then use an identity mapping.
65 if (!isa<LocalAsMetadata>(MD) && (Flags & RF_NoModuleLevelChanges))
66 return VM[V] = const_cast<Value *>(V);
68 auto *MappedMD = MapMetadata(MD, VM, Flags, TypeMapper, Materializer);
69 if (MD == MappedMD || (!MappedMD && (Flags & RF_IgnoreMissingEntries)))
70 return VM[V] = const_cast<Value *>(V);
72 // FIXME: This assert crashes during bootstrap, but I think it should be
73 // correct. For now, just match behaviour from before the metadata/value
76 // assert(MappedMD && "Referenced metadata value not in value map");
77 return VM[V] = MetadataAsValue::get(V->getContext(), MappedMD);
80 // Okay, this either must be a constant (which may or may not be mappable) or
81 // is something that is not in the mapping table.
82 Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V));
86 if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
88 cast<Function>(MapValue(BA->getFunction(), VM, Flags, TypeMapper, Materializer));
89 BasicBlock *BB = cast_or_null<BasicBlock>(MapValue(BA->getBasicBlock(), VM,
90 Flags, TypeMapper, Materializer));
91 return VM[V] = BlockAddress::get(F, BB ? BB : BA->getBasicBlock());
94 // Otherwise, we have some other constant to remap. Start by checking to see
95 // if all operands have an identity remapping.
96 unsigned OpNo = 0, NumOperands = C->getNumOperands();
97 Value *Mapped = nullptr;
98 for (; OpNo != NumOperands; ++OpNo) {
99 Value *Op = C->getOperand(OpNo);
100 Mapped = MapValue(Op, VM, Flags, TypeMapper, Materializer);
101 if (Mapped != C) break;
104 // See if the type mapper wants to remap the type as well.
105 Type *NewTy = C->getType();
107 NewTy = TypeMapper->remapType(NewTy);
109 // If the result type and all operands match up, then just insert an identity
111 if (OpNo == NumOperands && NewTy == C->getType())
114 // Okay, we need to create a new constant. We've already processed some or
115 // all of the operands, set them all up now.
116 SmallVector<Constant*, 8> Ops;
117 Ops.reserve(NumOperands);
118 for (unsigned j = 0; j != OpNo; ++j)
119 Ops.push_back(cast<Constant>(C->getOperand(j)));
121 // If one of the operands mismatch, push it and the other mapped operands.
122 if (OpNo != NumOperands) {
123 Ops.push_back(cast<Constant>(Mapped));
125 // Map the rest of the operands that aren't processed yet.
126 for (++OpNo; OpNo != NumOperands; ++OpNo)
127 Ops.push_back(MapValue(cast<Constant>(C->getOperand(OpNo)), VM,
128 Flags, TypeMapper, Materializer));
131 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
132 return VM[V] = CE->getWithOperands(Ops, NewTy);
133 if (isa<ConstantArray>(C))
134 return VM[V] = ConstantArray::get(cast<ArrayType>(NewTy), Ops);
135 if (isa<ConstantStruct>(C))
136 return VM[V] = ConstantStruct::get(cast<StructType>(NewTy), Ops);
137 if (isa<ConstantVector>(C))
138 return VM[V] = ConstantVector::get(Ops);
139 // If this is a no-operand constant, it must be because the type was remapped.
140 if (isa<UndefValue>(C))
141 return VM[V] = UndefValue::get(NewTy);
142 if (isa<ConstantAggregateZero>(C))
143 return VM[V] = ConstantAggregateZero::get(NewTy);
144 assert(isa<ConstantPointerNull>(C));
145 return VM[V] = ConstantPointerNull::get(cast<PointerType>(NewTy));
148 static Metadata *mapToMetadata(ValueToValueMapTy &VM, const Metadata *Key,
150 VM.MD()[Key].reset(Val);
154 static Metadata *mapToSelf(ValueToValueMapTy &VM, const Metadata *MD) {
155 return mapToMetadata(VM, MD, const_cast<Metadata *>(MD));
158 static Metadata *MapMetadataImpl(const Metadata *MD,
159 SmallVectorImpl<MDNode *> &DistinctWorklist,
160 ValueToValueMapTy &VM, RemapFlags Flags,
161 ValueMapTypeRemapper *TypeMapper,
162 ValueMaterializer *Materializer);
164 static Metadata *mapMetadataOp(Metadata *Op,
165 SmallVectorImpl<MDNode *> &DistinctWorklist,
166 ValueToValueMapTy &VM, RemapFlags Flags,
167 ValueMapTypeRemapper *TypeMapper,
168 ValueMaterializer *Materializer) {
171 if (Metadata *MappedOp = MapMetadataImpl(Op, DistinctWorklist, VM, Flags,
172 TypeMapper, Materializer))
174 // Use identity map if MappedOp is null and we can ignore missing entries.
175 if (Flags & RF_IgnoreMissingEntries)
178 // FIXME: This assert crashes during bootstrap, but I think it should be
179 // correct. For now, just match behaviour from before the metadata/value
182 // llvm_unreachable("Referenced metadata not in value map!");
186 /// Resolve uniquing cycles involving the given metadata.
187 static void resolveCycles(Metadata *MD) {
188 if (auto *N = dyn_cast_or_null<MDNode>(MD))
189 if (!N->isResolved())
193 /// Remap the operands of an MDNode.
195 /// If \c Node is temporary, uniquing cycles are ignored. If \c Node is
196 /// distinct, uniquing cycles are resolved as they're found.
198 /// \pre \c Node.isDistinct() or \c Node.isTemporary().
199 static bool remapOperands(MDNode &Node,
200 SmallVectorImpl<MDNode *> &DistinctWorklist,
201 ValueToValueMapTy &VM, RemapFlags Flags,
202 ValueMapTypeRemapper *TypeMapper,
203 ValueMaterializer *Materializer) {
204 assert(!Node.isUniqued() && "Expected temporary or distinct node");
205 const bool IsDistinct = Node.isDistinct();
207 bool AnyChanged = false;
208 for (unsigned I = 0, E = Node.getNumOperands(); I != E; ++I) {
209 Metadata *Old = Node.getOperand(I);
210 Metadata *New = mapMetadataOp(Old, DistinctWorklist, VM, Flags, TypeMapper,
214 Node.replaceOperandWith(I, New);
216 // Resolve uniquing cycles underneath distinct nodes on the fly so they
217 // don't infect later operands.
226 /// Map a distinct MDNode.
228 /// Whether distinct nodes change is independent of their operands. If \a
229 /// RF_MoveDistinctMDs, then they are reused, and their operands remapped in
230 /// place; effectively, they're moved from one graph to another. Otherwise,
231 /// they're cloned/duplicated, and the new copy's operands are remapped.
232 static Metadata *mapDistinctNode(const MDNode *Node,
233 SmallVectorImpl<MDNode *> &DistinctWorklist,
234 ValueToValueMapTy &VM, RemapFlags Flags,
235 ValueMapTypeRemapper *TypeMapper,
236 ValueMaterializer *Materializer) {
237 assert(Node->isDistinct() && "Expected distinct node");
240 if (Flags & RF_MoveDistinctMDs)
241 NewMD = const_cast<MDNode *>(Node);
243 NewMD = MDNode::replaceWithDistinct(Node->clone());
245 // Remap operands later.
246 DistinctWorklist.push_back(NewMD);
247 return mapToMetadata(VM, Node, NewMD);
250 /// \brief Map a uniqued MDNode.
252 /// Uniqued nodes may not need to be recreated (they may map to themselves).
253 static Metadata *mapUniquedNode(const MDNode *Node,
254 SmallVectorImpl<MDNode *> &DistinctWorklist,
255 ValueToValueMapTy &VM, RemapFlags Flags,
256 ValueMapTypeRemapper *TypeMapper,
257 ValueMaterializer *Materializer) {
258 assert(Node->isUniqued() && "Expected uniqued node");
260 // Create a temporary node and map it upfront in case we have a uniquing
261 // cycle. If necessary, this mapping will get updated by RAUW logic before
263 auto ClonedMD = Node->clone();
264 mapToMetadata(VM, Node, ClonedMD.get());
265 if (!remapOperands(*ClonedMD, DistinctWorklist, VM, Flags, TypeMapper,
267 // No operands changed, so use the original.
268 ClonedMD->replaceAllUsesWith(const_cast<MDNode *>(Node));
269 return const_cast<MDNode *>(Node);
272 // Uniquify the cloned node.
273 return MDNode::replaceWithUniqued(std::move(ClonedMD));
276 static Metadata *MapMetadataImpl(const Metadata *MD,
277 SmallVectorImpl<MDNode *> &DistinctWorklist,
278 ValueToValueMapTy &VM, RemapFlags Flags,
279 ValueMapTypeRemapper *TypeMapper,
280 ValueMaterializer *Materializer) {
281 // If the value already exists in the map, use it.
282 if (Metadata *NewMD = VM.MD().lookup(MD).get())
285 if (isa<MDString>(MD))
286 return mapToSelf(VM, MD);
288 if (isa<ConstantAsMetadata>(MD))
289 if ((Flags & RF_NoModuleLevelChanges))
290 return mapToSelf(VM, MD);
292 if (const auto *VMD = dyn_cast<ValueAsMetadata>(MD)) {
294 MapValue(VMD->getValue(), VM, Flags, TypeMapper, Materializer);
295 if (VMD->getValue() == MappedV ||
296 (!MappedV && (Flags & RF_IgnoreMissingEntries)))
297 return mapToSelf(VM, MD);
299 // FIXME: This assert crashes during bootstrap, but I think it should be
300 // correct. For now, just match behaviour from before the metadata/value
303 // assert(MappedV && "Referenced metadata not in value map!");
305 return mapToMetadata(VM, MD, ValueAsMetadata::get(MappedV));
309 // Note: this cast precedes the Flags check so we always get its associated
311 const MDNode *Node = cast<MDNode>(MD);
313 // If this is a module-level metadata and we know that nothing at the
314 // module level is changing, then use an identity mapping.
315 if (Flags & RF_NoModuleLevelChanges)
316 return mapToSelf(VM, MD);
318 // Require resolved nodes whenever metadata might be remapped.
319 assert(Node->isResolved() && "Unexpected unresolved node");
321 if (Node->isDistinct())
322 return mapDistinctNode(Node, DistinctWorklist, VM, Flags, TypeMapper,
325 return mapUniquedNode(Node, DistinctWorklist, VM, Flags, TypeMapper,
329 Metadata *llvm::MapMetadata(const Metadata *MD, ValueToValueMapTy &VM,
330 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
331 ValueMaterializer *Materializer) {
332 SmallVector<MDNode *, 8> DistinctWorklist;
333 Metadata *NewMD = MapMetadataImpl(MD, DistinctWorklist, VM, Flags, TypeMapper,
336 // When there are no module-level changes, it's possible that the metadata
337 // graph has temporaries. Skip the logic to resolve cycles, since it's
338 // unnecessary (and invalid) in that case.
339 if (Flags & RF_NoModuleLevelChanges)
342 // Resolve cycles involving the entry metadata.
343 resolveCycles(NewMD);
345 // Remap the operands of distinct MDNodes.
346 while (!DistinctWorklist.empty())
347 remapOperands(*DistinctWorklist.pop_back_val(), DistinctWorklist, VM, Flags,
348 TypeMapper, Materializer);
353 MDNode *llvm::MapMetadata(const MDNode *MD, ValueToValueMapTy &VM,
354 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
355 ValueMaterializer *Materializer) {
356 return cast<MDNode>(MapMetadata(static_cast<const Metadata *>(MD), VM, Flags,
357 TypeMapper, Materializer));
360 /// RemapInstruction - Convert the instruction operands from referencing the
361 /// current values into those specified by VMap.
363 void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
364 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
365 ValueMaterializer *Materializer){
367 for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
368 Value *V = MapValue(*op, VMap, Flags, TypeMapper, Materializer);
369 // If we aren't ignoring missing entries, assert that something happened.
373 assert((Flags & RF_IgnoreMissingEntries) &&
374 "Referenced value not in value map!");
377 // Remap phi nodes' incoming blocks.
378 if (PHINode *PN = dyn_cast<PHINode>(I)) {
379 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
380 Value *V = MapValue(PN->getIncomingBlock(i), VMap, Flags);
381 // If we aren't ignoring missing entries, assert that something happened.
383 PN->setIncomingBlock(i, cast<BasicBlock>(V));
385 assert((Flags & RF_IgnoreMissingEntries) &&
386 "Referenced block not in value map!");
390 // Remap attached metadata.
391 SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
392 I->getAllMetadata(MDs);
393 for (const auto &MI : MDs) {
394 MDNode *Old = MI.second;
395 MDNode *New = MapMetadata(Old, VMap, Flags, TypeMapper, Materializer);
397 I->setMetadata(MI.first, New);
403 // If the instruction's type is being remapped, do so now.
404 if (auto CS = CallSite(I)) {
405 SmallVector<Type *, 3> Tys;
406 FunctionType *FTy = CS.getFunctionType();
407 Tys.reserve(FTy->getNumParams());
408 for (Type *Ty : FTy->params())
409 Tys.push_back(TypeMapper->remapType(Ty));
410 CS.mutateFunctionType(FunctionType::get(
411 TypeMapper->remapType(I->getType()), Tys, FTy->isVarArg()));
414 if (auto *AI = dyn_cast<AllocaInst>(I))
415 AI->setAllocatedType(TypeMapper->remapType(AI->getAllocatedType()));
416 if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) {
417 GEP->setSourceElementType(
418 TypeMapper->remapType(GEP->getSourceElementType()));
419 GEP->setResultElementType(
420 TypeMapper->remapType(GEP->getResultElementType()));
422 I->mutateType(TypeMapper->remapType(I->getType()));