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() {}
29 Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM, RemapFlags Flags,
30 ValueMapTypeRemapper *TypeMapper,
31 ValueMaterializer *Materializer) {
32 ValueToValueMapTy::iterator I = VM.find(V);
34 // If the value already exists in the map, use it.
35 if (I != VM.end() && I->second) return I->second;
37 // If we have a materializer and it can materialize a value, use that.
39 if (Value *NewV = Materializer->materializeValueFor(const_cast<Value*>(V)))
43 // Global values do not need to be seeded into the VM if they
44 // are using the identity mapping.
45 if (isa<GlobalValue>(V)) {
46 if (Flags & RF_NullMapMissingGlobalValues) {
47 assert(!(Flags & RF_IgnoreMissingEntries) &&
48 "Illegal to specify both RF_NullMapMissingGlobalValues and "
49 "RF_IgnoreMissingEntries");
52 return VM[V] = const_cast<Value*>(V);
55 if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
56 // Inline asm may need *type* remapping.
57 FunctionType *NewTy = IA->getFunctionType();
59 NewTy = cast<FunctionType>(TypeMapper->remapType(NewTy));
61 if (NewTy != IA->getFunctionType())
62 V = InlineAsm::get(NewTy, IA->getAsmString(), IA->getConstraintString(),
63 IA->hasSideEffects(), IA->isAlignStack());
66 return VM[V] = const_cast<Value*>(V);
69 if (const auto *MDV = dyn_cast<MetadataAsValue>(V)) {
70 const Metadata *MD = MDV->getMetadata();
71 // If this is a module-level metadata and we know that nothing at the module
72 // level is changing, then use an identity mapping.
73 if (!isa<LocalAsMetadata>(MD) && (Flags & RF_NoModuleLevelChanges))
74 return VM[V] = const_cast<Value *>(V);
76 auto *MappedMD = MapMetadata(MD, VM, Flags, TypeMapper, Materializer);
77 if (MD == MappedMD || (!MappedMD && (Flags & RF_IgnoreMissingEntries)))
78 return VM[V] = const_cast<Value *>(V);
80 // FIXME: This assert crashes during bootstrap, but I think it should be
81 // correct. For now, just match behaviour from before the metadata/value
84 // assert((MappedMD || (Flags & RF_NullMapMissingGlobalValues)) &&
85 // "Referenced metadata value not in value map");
86 return VM[V] = MetadataAsValue::get(V->getContext(), MappedMD);
89 // Okay, this either must be a constant (which may or may not be mappable) or
90 // is something that is not in the mapping table.
91 Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V));
95 if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
97 cast<Function>(MapValue(BA->getFunction(), VM, Flags, TypeMapper, Materializer));
98 BasicBlock *BB = cast_or_null<BasicBlock>(MapValue(BA->getBasicBlock(), VM,
99 Flags, TypeMapper, Materializer));
100 return VM[V] = BlockAddress::get(F, BB ? BB : BA->getBasicBlock());
103 // Otherwise, we have some other constant to remap. Start by checking to see
104 // if all operands have an identity remapping.
105 unsigned OpNo = 0, NumOperands = C->getNumOperands();
106 Value *Mapped = nullptr;
107 for (; OpNo != NumOperands; ++OpNo) {
108 Value *Op = C->getOperand(OpNo);
109 Mapped = MapValue(Op, VM, Flags, TypeMapper, Materializer);
110 if (Mapped != C) break;
113 // See if the type mapper wants to remap the type as well.
114 Type *NewTy = C->getType();
116 NewTy = TypeMapper->remapType(NewTy);
118 // If the result type and all operands match up, then just insert an identity
120 if (OpNo == NumOperands && NewTy == C->getType())
123 // Okay, we need to create a new constant. We've already processed some or
124 // all of the operands, set them all up now.
125 SmallVector<Constant*, 8> Ops;
126 Ops.reserve(NumOperands);
127 for (unsigned j = 0; j != OpNo; ++j)
128 Ops.push_back(cast<Constant>(C->getOperand(j)));
130 // If one of the operands mismatch, push it and the other mapped operands.
131 if (OpNo != NumOperands) {
132 Ops.push_back(cast<Constant>(Mapped));
134 // Map the rest of the operands that aren't processed yet.
135 for (++OpNo; OpNo != NumOperands; ++OpNo)
136 Ops.push_back(MapValue(cast<Constant>(C->getOperand(OpNo)), VM,
137 Flags, TypeMapper, Materializer));
139 Type *NewSrcTy = nullptr;
141 if (auto *GEPO = dyn_cast<GEPOperator>(C))
142 NewSrcTy = TypeMapper->remapType(GEPO->getSourceElementType());
144 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
145 return VM[V] = CE->getWithOperands(Ops, NewTy, false, NewSrcTy);
146 if (isa<ConstantArray>(C))
147 return VM[V] = ConstantArray::get(cast<ArrayType>(NewTy), Ops);
148 if (isa<ConstantStruct>(C))
149 return VM[V] = ConstantStruct::get(cast<StructType>(NewTy), Ops);
150 if (isa<ConstantVector>(C))
151 return VM[V] = ConstantVector::get(Ops);
152 // If this is a no-operand constant, it must be because the type was remapped.
153 if (isa<UndefValue>(C))
154 return VM[V] = UndefValue::get(NewTy);
155 if (isa<ConstantAggregateZero>(C))
156 return VM[V] = ConstantAggregateZero::get(NewTy);
157 assert(isa<ConstantPointerNull>(C));
158 return VM[V] = ConstantPointerNull::get(cast<PointerType>(NewTy));
161 static Metadata *mapToMetadata(ValueToValueMapTy &VM, const Metadata *Key,
163 VM.MD()[Key].reset(Val);
167 static Metadata *mapToSelf(ValueToValueMapTy &VM, const Metadata *MD) {
168 return mapToMetadata(VM, MD, const_cast<Metadata *>(MD));
171 static Metadata *MapMetadataImpl(const Metadata *MD,
172 SmallVectorImpl<MDNode *> &DistinctWorklist,
173 ValueToValueMapTy &VM, RemapFlags Flags,
174 ValueMapTypeRemapper *TypeMapper,
175 ValueMaterializer *Materializer);
177 static Metadata *mapMetadataOp(Metadata *Op,
178 SmallVectorImpl<MDNode *> &DistinctWorklist,
179 ValueToValueMapTy &VM, RemapFlags Flags,
180 ValueMapTypeRemapper *TypeMapper,
181 ValueMaterializer *Materializer) {
184 if (Metadata *MappedOp = MapMetadataImpl(Op, DistinctWorklist, VM, Flags,
185 TypeMapper, Materializer))
187 // Use identity map if MappedOp is null and we can ignore missing entries.
188 if (Flags & RF_IgnoreMissingEntries)
191 // FIXME: This assert crashes during bootstrap, but I think it should be
192 // correct. For now, just match behaviour from before the metadata/value
195 // assert((Flags & RF_NullMapMissingGlobalValues) &&
196 // "Referenced metadata not in value map!");
200 /// Resolve uniquing cycles involving the given metadata.
201 static void resolveCycles(Metadata *MD) {
202 if (auto *N = dyn_cast_or_null<MDNode>(MD))
203 if (!N->isResolved())
207 /// Remap the operands of an MDNode.
209 /// If \c Node is temporary, uniquing cycles are ignored. If \c Node is
210 /// distinct, uniquing cycles are resolved as they're found.
212 /// \pre \c Node.isDistinct() or \c Node.isTemporary().
213 static bool remapOperands(MDNode &Node,
214 SmallVectorImpl<MDNode *> &DistinctWorklist,
215 ValueToValueMapTy &VM, RemapFlags Flags,
216 ValueMapTypeRemapper *TypeMapper,
217 ValueMaterializer *Materializer) {
218 assert(!Node.isUniqued() && "Expected temporary or distinct node");
219 const bool IsDistinct = Node.isDistinct();
221 bool AnyChanged = false;
222 for (unsigned I = 0, E = Node.getNumOperands(); I != E; ++I) {
223 Metadata *Old = Node.getOperand(I);
224 Metadata *New = mapMetadataOp(Old, DistinctWorklist, VM, Flags, TypeMapper,
228 Node.replaceOperandWith(I, New);
230 // Resolve uniquing cycles underneath distinct nodes on the fly so they
231 // don't infect later operands.
240 /// Map a distinct MDNode.
242 /// Whether distinct nodes change is independent of their operands. If \a
243 /// RF_MoveDistinctMDs, then they are reused, and their operands remapped in
244 /// place; effectively, they're moved from one graph to another. Otherwise,
245 /// they're cloned/duplicated, and the new copy's operands are remapped.
246 static Metadata *mapDistinctNode(const MDNode *Node,
247 SmallVectorImpl<MDNode *> &DistinctWorklist,
248 ValueToValueMapTy &VM, RemapFlags Flags,
249 ValueMapTypeRemapper *TypeMapper,
250 ValueMaterializer *Materializer) {
251 assert(Node->isDistinct() && "Expected distinct node");
254 if (Flags & RF_MoveDistinctMDs)
255 NewMD = const_cast<MDNode *>(Node);
257 NewMD = MDNode::replaceWithDistinct(Node->clone());
259 // Remap operands later.
260 DistinctWorklist.push_back(NewMD);
261 return mapToMetadata(VM, Node, NewMD);
264 /// \brief Map a uniqued MDNode.
266 /// Uniqued nodes may not need to be recreated (they may map to themselves).
267 static Metadata *mapUniquedNode(const MDNode *Node,
268 SmallVectorImpl<MDNode *> &DistinctWorklist,
269 ValueToValueMapTy &VM, RemapFlags Flags,
270 ValueMapTypeRemapper *TypeMapper,
271 ValueMaterializer *Materializer) {
272 assert(Node->isUniqued() && "Expected uniqued node");
274 // Create a temporary node and map it upfront in case we have a uniquing
275 // cycle. If necessary, this mapping will get updated by RAUW logic before
277 auto ClonedMD = Node->clone();
278 mapToMetadata(VM, Node, ClonedMD.get());
279 if (!remapOperands(*ClonedMD, DistinctWorklist, VM, Flags, TypeMapper,
281 // No operands changed, so use the original.
282 ClonedMD->replaceAllUsesWith(const_cast<MDNode *>(Node));
283 return const_cast<MDNode *>(Node);
286 // Uniquify the cloned node.
287 return MDNode::replaceWithUniqued(std::move(ClonedMD));
290 static Metadata *MapMetadataImpl(const Metadata *MD,
291 SmallVectorImpl<MDNode *> &DistinctWorklist,
292 ValueToValueMapTy &VM, RemapFlags Flags,
293 ValueMapTypeRemapper *TypeMapper,
294 ValueMaterializer *Materializer) {
295 // If the value already exists in the map, use it.
296 if (Metadata *NewMD = VM.MD().lookup(MD).get())
299 if (isa<MDString>(MD))
300 return mapToSelf(VM, MD);
302 if (isa<ConstantAsMetadata>(MD))
303 if ((Flags & RF_NoModuleLevelChanges))
304 return mapToSelf(VM, MD);
306 if (const auto *VMD = dyn_cast<ValueAsMetadata>(MD)) {
308 MapValue(VMD->getValue(), VM, Flags, TypeMapper, Materializer);
309 if (VMD->getValue() == MappedV ||
310 (!MappedV && (Flags & RF_IgnoreMissingEntries)))
311 return mapToSelf(VM, MD);
313 // FIXME: This assert crashes during bootstrap, but I think it should be
314 // correct. For now, just match behaviour from before the metadata/value
317 // assert((MappedV || (Flags & RF_NullMapMissingGlobalValues)) &&
318 // "Referenced metadata not in value map!");
320 return mapToMetadata(VM, MD, ValueAsMetadata::get(MappedV));
324 // Note: this cast precedes the Flags check so we always get its associated
326 const MDNode *Node = cast<MDNode>(MD);
328 // If this is a module-level metadata and we know that nothing at the
329 // module level is changing, then use an identity mapping.
330 if (Flags & RF_NoModuleLevelChanges)
331 return mapToSelf(VM, MD);
333 // Require resolved nodes whenever metadata might be remapped.
334 assert(Node->isResolved() && "Unexpected unresolved node");
336 if (Node->isDistinct())
337 return mapDistinctNode(Node, DistinctWorklist, VM, Flags, TypeMapper,
340 return mapUniquedNode(Node, DistinctWorklist, VM, Flags, TypeMapper,
344 Metadata *llvm::MapMetadata(const Metadata *MD, ValueToValueMapTy &VM,
345 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
346 ValueMaterializer *Materializer) {
347 SmallVector<MDNode *, 8> DistinctWorklist;
348 Metadata *NewMD = MapMetadataImpl(MD, DistinctWorklist, VM, Flags, TypeMapper,
351 // When there are no module-level changes, it's possible that the metadata
352 // graph has temporaries. Skip the logic to resolve cycles, since it's
353 // unnecessary (and invalid) in that case.
354 if (Flags & RF_NoModuleLevelChanges)
357 // Resolve cycles involving the entry metadata.
358 resolveCycles(NewMD);
360 // Remap the operands of distinct MDNodes.
361 while (!DistinctWorklist.empty())
362 remapOperands(*DistinctWorklist.pop_back_val(), DistinctWorklist, VM, Flags,
363 TypeMapper, Materializer);
368 MDNode *llvm::MapMetadata(const MDNode *MD, ValueToValueMapTy &VM,
369 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
370 ValueMaterializer *Materializer) {
371 return cast<MDNode>(MapMetadata(static_cast<const Metadata *>(MD), VM, Flags,
372 TypeMapper, Materializer));
375 /// RemapInstruction - Convert the instruction operands from referencing the
376 /// current values into those specified by VMap.
378 void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
379 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
380 ValueMaterializer *Materializer){
382 for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
383 Value *V = MapValue(*op, VMap, Flags, TypeMapper, Materializer);
384 // If we aren't ignoring missing entries, assert that something happened.
388 assert((Flags & RF_IgnoreMissingEntries) &&
389 "Referenced value not in value map!");
392 // Remap phi nodes' incoming blocks.
393 if (PHINode *PN = dyn_cast<PHINode>(I)) {
394 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
395 Value *V = MapValue(PN->getIncomingBlock(i), VMap, Flags);
396 // If we aren't ignoring missing entries, assert that something happened.
398 PN->setIncomingBlock(i, cast<BasicBlock>(V));
400 assert((Flags & RF_IgnoreMissingEntries) &&
401 "Referenced block not in value map!");
405 // Remap attached metadata.
406 SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
407 I->getAllMetadata(MDs);
408 for (const auto &MI : MDs) {
409 MDNode *Old = MI.second;
410 MDNode *New = MapMetadata(Old, VMap, Flags, TypeMapper, Materializer);
412 I->setMetadata(MI.first, New);
418 // If the instruction's type is being remapped, do so now.
419 if (auto CS = CallSite(I)) {
420 SmallVector<Type *, 3> Tys;
421 FunctionType *FTy = CS.getFunctionType();
422 Tys.reserve(FTy->getNumParams());
423 for (Type *Ty : FTy->params())
424 Tys.push_back(TypeMapper->remapType(Ty));
425 CS.mutateFunctionType(FunctionType::get(
426 TypeMapper->remapType(I->getType()), Tys, FTy->isVarArg()));
429 if (auto *AI = dyn_cast<AllocaInst>(I))
430 AI->setAllocatedType(TypeMapper->remapType(AI->getAllocatedType()));
431 if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) {
432 GEP->setSourceElementType(
433 TypeMapper->remapType(GEP->getSourceElementType()));
434 GEP->setResultElementType(
435 TypeMapper->remapType(GEP->getResultElementType()));
437 I->mutateType(TypeMapper->remapType(I->getType()));