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 *> &Cycles,
160 ValueToValueMapTy &VM, RemapFlags Flags,
161 ValueMapTypeRemapper *TypeMapper,
162 ValueMaterializer *Materializer);
164 static Metadata *mapMetadataOp(Metadata *Op, SmallVectorImpl<MDNode *> &Cycles,
165 ValueToValueMapTy &VM, RemapFlags Flags,
166 ValueMapTypeRemapper *TypeMapper,
167 ValueMaterializer *Materializer) {
170 if (Metadata *MappedOp =
171 MapMetadataImpl(Op, Cycles, VM, Flags, TypeMapper, Materializer))
173 // Use identity map if MappedOp is null and we can ignore missing entries.
174 if (Flags & RF_IgnoreMissingEntries)
177 // FIXME: This assert crashes during bootstrap, but I think it should be
178 // correct. For now, just match behaviour from before the metadata/value
181 // llvm_unreachable("Referenced metadata not in value map!");
185 /// \brief Remap nodes.
187 /// Insert \c NewNode in the value map, and then remap \c OldNode's operands.
188 /// Assumes that \c NewNode is already a clone of \c OldNode.
190 /// \pre \c NewNode is a clone of \c OldNode.
191 static bool remap(const MDNode *OldNode, MDNode *NewNode,
192 SmallVectorImpl<MDNode *> &Cycles, ValueToValueMapTy &VM,
193 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
194 ValueMaterializer *Materializer) {
195 assert(OldNode->getNumOperands() == NewNode->getNumOperands() &&
196 "Expected nodes to match");
197 assert(OldNode->isResolved() && "Expected resolved node");
198 assert(!NewNode->isUniqued() && "Expected non-uniqued node");
200 // Map the node upfront so it's available for cyclic references.
201 mapToMetadata(VM, OldNode, NewNode);
202 bool AnyChanged = false;
203 for (unsigned I = 0, E = OldNode->getNumOperands(); I != E; ++I) {
204 Metadata *Old = OldNode->getOperand(I);
205 assert(NewNode->getOperand(I) == Old &&
206 "Expected old operands to already be in place");
209 mapMetadataOp(Old, Cycles, VM, Flags, TypeMapper, Materializer);
212 NewNode->replaceOperandWith(I, New);
219 /// Map a distinct MDNode.
221 /// Whether distinct nodes change is independent of their operands. If \a
222 /// RF_MoveDistinctMDs, then they are reused, and their operands remapped in
223 /// place; effectively, they're moved from one graph to another. Otherwise,
224 /// they're cloned/duplicated, and the new copy's operands are remapped.
225 static Metadata *mapDistinctNode(const MDNode *Node,
226 SmallVectorImpl<MDNode *> &Cycles,
227 ValueToValueMapTy &VM, RemapFlags Flags,
228 ValueMapTypeRemapper *TypeMapper,
229 ValueMaterializer *Materializer) {
230 assert(Node->isDistinct() && "Expected distinct node");
233 if (Flags & RF_MoveDistinctMDs)
234 NewMD = const_cast<MDNode *>(Node);
236 NewMD = MDNode::replaceWithDistinct(Node->clone());
238 // Remap the operands. If any change, track those that could be involved in
240 if (remap(Node, NewMD, Cycles, VM, Flags, TypeMapper, Materializer))
241 for (Metadata *Op : NewMD->operands())
242 if (auto *Node = dyn_cast_or_null<MDNode>(Op))
243 if (!Node->isResolved())
244 Cycles.push_back(Node);
249 /// \brief Map a uniqued MDNode.
251 /// Uniqued nodes may not need to be recreated (they may map to themselves).
252 static Metadata *mapUniquedNode(const MDNode *Node,
253 SmallVectorImpl<MDNode *> &Cycles,
254 ValueToValueMapTy &VM, RemapFlags Flags,
255 ValueMapTypeRemapper *TypeMapper,
256 ValueMaterializer *Materializer) {
257 assert(Node->isUniqued() && "Expected uniqued node");
259 // Create a temporary node upfront in case we have a metadata cycle.
260 auto ClonedMD = Node->clone();
261 if (!remap(Node, ClonedMD.get(), Cycles, VM, Flags, TypeMapper, Materializer)) {
262 // No operands changed, so use the identity mapping.
263 ClonedMD->replaceAllUsesWith(const_cast<MDNode *>(Node));
264 return mapToSelf(VM, Node);
267 // At least one operand has changed, so uniquify the cloned node.
268 return mapToMetadata(VM, Node,
269 MDNode::replaceWithUniqued(std::move(ClonedMD)));
272 static Metadata *MapMetadataImpl(const Metadata *MD,
273 SmallVectorImpl<MDNode *> &Cycles,
274 ValueToValueMapTy &VM, RemapFlags Flags,
275 ValueMapTypeRemapper *TypeMapper,
276 ValueMaterializer *Materializer) {
277 // If the value already exists in the map, use it.
278 if (Metadata *NewMD = VM.MD().lookup(MD).get())
281 if (isa<MDString>(MD))
282 return mapToSelf(VM, MD);
284 if (isa<ConstantAsMetadata>(MD))
285 if ((Flags & RF_NoModuleLevelChanges))
286 return mapToSelf(VM, MD);
288 if (const auto *VMD = dyn_cast<ValueAsMetadata>(MD)) {
290 MapValue(VMD->getValue(), VM, Flags, TypeMapper, Materializer);
291 if (VMD->getValue() == MappedV ||
292 (!MappedV && (Flags & RF_IgnoreMissingEntries)))
293 return mapToSelf(VM, MD);
295 // FIXME: This assert crashes during bootstrap, but I think it should be
296 // correct. For now, just match behaviour from before the metadata/value
299 // assert(MappedV && "Referenced metadata not in value map!");
301 return mapToMetadata(VM, MD, ValueAsMetadata::get(MappedV));
305 // Note: this cast precedes the Flags check so we always get its associated
307 const MDNode *Node = cast<MDNode>(MD);
309 // If this is a module-level metadata and we know that nothing at the
310 // module level is changing, then use an identity mapping.
311 if (Flags & RF_NoModuleLevelChanges)
312 return mapToSelf(VM, MD);
314 // Require resolved nodes whenever metadata might be remapped.
315 assert(Node->isResolved() && "Unexpected unresolved node");
317 if (Node->isDistinct())
318 return mapDistinctNode(Node, Cycles, VM, Flags, TypeMapper, Materializer);
320 return mapUniquedNode(Node, Cycles, VM, Flags, TypeMapper, Materializer);
323 Metadata *llvm::MapMetadata(const Metadata *MD, ValueToValueMapTy &VM,
324 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
325 ValueMaterializer *Materializer) {
326 SmallVector<MDNode *, 8> Cycles;
328 MapMetadataImpl(MD, Cycles, VM, Flags, TypeMapper, Materializer);
330 if ((Flags & RF_NoModuleLevelChanges) ||
331 (MD == NewMD && !(Flags & RF_MoveDistinctMDs))) {
332 assert(Cycles.empty() && "Unresolved cycles without remapping anything?");
336 if (auto *N = dyn_cast<MDNode>(NewMD))
337 if (!N->isResolved())
340 // Resolve cycles underneath MD.
341 for (MDNode *N : Cycles)
342 if (!N->isResolved())
348 MDNode *llvm::MapMetadata(const MDNode *MD, ValueToValueMapTy &VM,
349 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
350 ValueMaterializer *Materializer) {
351 return cast<MDNode>(MapMetadata(static_cast<const Metadata *>(MD), VM, Flags,
352 TypeMapper, Materializer));
355 /// RemapInstruction - Convert the instruction operands from referencing the
356 /// current values into those specified by VMap.
358 void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
359 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
360 ValueMaterializer *Materializer){
362 for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
363 Value *V = MapValue(*op, VMap, Flags, TypeMapper, Materializer);
364 // If we aren't ignoring missing entries, assert that something happened.
368 assert((Flags & RF_IgnoreMissingEntries) &&
369 "Referenced value not in value map!");
372 // Remap phi nodes' incoming blocks.
373 if (PHINode *PN = dyn_cast<PHINode>(I)) {
374 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
375 Value *V = MapValue(PN->getIncomingBlock(i), VMap, Flags);
376 // If we aren't ignoring missing entries, assert that something happened.
378 PN->setIncomingBlock(i, cast<BasicBlock>(V));
380 assert((Flags & RF_IgnoreMissingEntries) &&
381 "Referenced block not in value map!");
385 // Remap attached metadata.
386 SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
387 I->getAllMetadata(MDs);
388 for (const auto &MI : MDs) {
389 MDNode *Old = MI.second;
390 MDNode *New = MapMetadata(Old, VMap, Flags, TypeMapper, Materializer);
392 I->setMetadata(MI.first, New);
398 // If the instruction's type is being remapped, do so now.
399 if (auto CS = CallSite(I)) {
400 SmallVector<Type *, 3> Tys;
401 FunctionType *FTy = CS.getFunctionType();
402 Tys.reserve(FTy->getNumParams());
403 for (Type *Ty : FTy->params())
404 Tys.push_back(TypeMapper->remapType(Ty));
405 CS.mutateFunctionType(FunctionType::get(
406 TypeMapper->remapType(I->getType()), Tys, FTy->isVarArg()));
409 if (auto *AI = dyn_cast<AllocaInst>(I))
410 AI->setAllocatedType(TypeMapper->remapType(AI->getAllocatedType()));
411 if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) {
412 GEP->setSourceElementType(
413 TypeMapper->remapType(GEP->getSourceElementType()));
414 GEP->setResultElementType(
415 TypeMapper->remapType(GEP->getResultElementType()));
417 I->mutateType(TypeMapper->remapType(I->getType()));