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/Constants.h"
17 #include "llvm/IR/Function.h"
18 #include "llvm/IR/InlineAsm.h"
19 #include "llvm/IR/Instructions.h"
20 #include "llvm/IR/Metadata.h"
23 // Out of line method to get vtable etc for class.
24 void ValueMapTypeRemapper::anchor() {}
25 void ValueMaterializer::anchor() {}
27 Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM, RemapFlags Flags,
28 ValueMapTypeRemapper *TypeMapper,
29 ValueMaterializer *Materializer) {
30 ValueToValueMapTy::iterator I = VM.find(V);
32 // If the value already exists in the map, use it.
33 if (I != VM.end() && I->second) return I->second;
35 // If we have a materializer and it can materialize a value, use that.
37 if (Value *NewV = Materializer->materializeValueFor(const_cast<Value*>(V)))
41 // Global values do not need to be seeded into the VM if they
42 // are using the identity mapping.
43 if (isa<GlobalValue>(V))
44 return VM[V] = const_cast<Value*>(V);
46 if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
47 // Inline asm may need *type* remapping.
48 FunctionType *NewTy = IA->getFunctionType();
50 NewTy = cast<FunctionType>(TypeMapper->remapType(NewTy));
52 if (NewTy != IA->getFunctionType())
53 V = InlineAsm::get(NewTy, IA->getAsmString(), IA->getConstraintString(),
54 IA->hasSideEffects(), IA->isAlignStack());
57 return VM[V] = const_cast<Value*>(V);
60 if (const auto *MDV = dyn_cast<MetadataAsValue>(V)) {
61 const Metadata *MD = MDV->getMetadata();
62 // If this is a module-level metadata and we know that nothing at the module
63 // level is changing, then use an identity mapping.
64 if (!isa<LocalAsMetadata>(MD) && (Flags & RF_NoModuleLevelChanges))
65 return VM[V] = const_cast<Value *>(V);
67 auto *MappedMD = MapValue(MD, VM, Flags, TypeMapper, Materializer);
68 if (MD == MappedMD || (!MappedMD && (Flags & RF_IgnoreMissingEntries)))
69 return VM[V] = const_cast<Value *>(V);
71 // FIXME: This assert crashes during bootstrap, but I think it should be
72 // correct. For now, just match behaviour from before the metadata/value
75 // assert(MappedMD && "Referenced metadata value not in value map");
76 return VM[V] = MetadataAsValue::get(V->getContext(), MappedMD);
79 // Okay, this either must be a constant (which may or may not be mappable) or
80 // is something that is not in the mapping table.
81 Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V));
85 if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
87 cast<Function>(MapValue(BA->getFunction(), VM, Flags, TypeMapper, Materializer));
88 BasicBlock *BB = cast_or_null<BasicBlock>(MapValue(BA->getBasicBlock(), VM,
89 Flags, TypeMapper, Materializer));
90 return VM[V] = BlockAddress::get(F, BB ? BB : BA->getBasicBlock());
93 // Otherwise, we have some other constant to remap. Start by checking to see
94 // if all operands have an identity remapping.
95 unsigned OpNo = 0, NumOperands = C->getNumOperands();
96 Value *Mapped = nullptr;
97 for (; OpNo != NumOperands; ++OpNo) {
98 Value *Op = C->getOperand(OpNo);
99 Mapped = MapValue(Op, VM, Flags, TypeMapper, Materializer);
100 if (Mapped != C) break;
103 // See if the type mapper wants to remap the type as well.
104 Type *NewTy = C->getType();
106 NewTy = TypeMapper->remapType(NewTy);
108 // If the result type and all operands match up, then just insert an identity
110 if (OpNo == NumOperands && NewTy == C->getType())
113 // Okay, we need to create a new constant. We've already processed some or
114 // all of the operands, set them all up now.
115 SmallVector<Constant*, 8> Ops;
116 Ops.reserve(NumOperands);
117 for (unsigned j = 0; j != OpNo; ++j)
118 Ops.push_back(cast<Constant>(C->getOperand(j)));
120 // If one of the operands mismatch, push it and the other mapped operands.
121 if (OpNo != NumOperands) {
122 Ops.push_back(cast<Constant>(Mapped));
124 // Map the rest of the operands that aren't processed yet.
125 for (++OpNo; OpNo != NumOperands; ++OpNo)
126 Ops.push_back(MapValue(cast<Constant>(C->getOperand(OpNo)), VM,
127 Flags, TypeMapper, Materializer));
130 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
131 return VM[V] = CE->getWithOperands(Ops, NewTy);
132 if (isa<ConstantArray>(C))
133 return VM[V] = ConstantArray::get(cast<ArrayType>(NewTy), Ops);
134 if (isa<ConstantStruct>(C))
135 return VM[V] = ConstantStruct::get(cast<StructType>(NewTy), Ops);
136 if (isa<ConstantVector>(C))
137 return VM[V] = ConstantVector::get(Ops);
138 // If this is a no-operand constant, it must be because the type was remapped.
139 if (isa<UndefValue>(C))
140 return VM[V] = UndefValue::get(NewTy);
141 if (isa<ConstantAggregateZero>(C))
142 return VM[V] = ConstantAggregateZero::get(NewTy);
143 assert(isa<ConstantPointerNull>(C));
144 return VM[V] = ConstantPointerNull::get(cast<PointerType>(NewTy));
147 static Metadata *map(ValueToValueMapTy &VM, const Metadata *Key,
149 VM.MD()[Key].reset(Val);
153 static Metadata *mapToSelf(ValueToValueMapTy &VM, const Metadata *MD) {
154 return map(VM, MD, const_cast<Metadata *>(MD));
157 static Metadata *MapValueImpl(const Metadata *MD, ValueToValueMapTy &VM,
159 ValueMapTypeRemapper *TypeMapper,
160 ValueMaterializer *Materializer) {
161 // If the value already exists in the map, use it.
162 if (Metadata *NewMD = VM.MD().lookup(MD).get())
165 if (isa<MDString>(MD))
166 return mapToSelf(VM, MD);
168 if (isa<ConstantAsMetadata>(MD))
169 if ((Flags & RF_NoModuleLevelChanges))
170 return mapToSelf(VM, MD);
172 if (const auto *VMD = dyn_cast<ValueAsMetadata>(MD)) {
174 MapValue(VMD->getValue(), VM, Flags, TypeMapper, Materializer);
175 if (VMD->getValue() == MappedV ||
176 (!MappedV && (Flags & RF_IgnoreMissingEntries)))
177 return mapToSelf(VM, MD);
179 // FIXME: This assert crashes during bootstrap, but I think it should be
180 // correct. For now, just match behaviour from before the metadata/value
183 // assert(MappedV && "Referenced metadata not in value map!");
185 return map(VM, MD, ValueAsMetadata::get(MappedV));
189 const MDNode *Node = cast<MDNode>(MD);
190 assert(Node->isResolved() && "Unexpected unresolved node");
192 auto getMappedOp = [&](Metadata *Op) -> Metadata *{
195 if (Metadata *MappedOp =
196 MapValueImpl(Op, VM, Flags, TypeMapper, Materializer))
198 // Use identity map if MappedOp is null and we can ignore missing entries.
199 if (Flags & RF_IgnoreMissingEntries)
202 // FIXME: This assert crashes during bootstrap, but I think it should be
203 // correct. For now, just match behaviour from before the metadata/value
206 // llvm_unreachable("Referenced metadata not in value map!");
210 // If this is a module-level metadata and we know that nothing at the
211 // module level is changing, then use an identity mapping.
212 if (Flags & RF_NoModuleLevelChanges)
213 return mapToSelf(VM, MD);
215 // Create a dummy node in case we have a metadata cycle.
216 MDNodeFwdDecl *Dummy = MDNode::getTemporary(Node->getContext(), None);
217 map(VM, Node, Dummy);
219 // Check all operands to see if any need to be remapped.
220 for (unsigned I = 0, E = Node->getNumOperands(); I != E; ++I) {
221 Metadata *Op = Node->getOperand(I);
222 Metadata *MappedOp = getMappedOp(Op);
226 // Ok, at least one operand needs remapping.
227 SmallVector<Metadata *, 4> Elts;
228 Elts.reserve(Node->getNumOperands());
229 for (I = 0; I != E; ++I)
230 Elts.push_back(getMappedOp(Node->getOperand(I)));
232 MDNode *NewMD = MDNode::get(Node->getContext(), Elts);
233 Dummy->replaceAllUsesWith(NewMD);
234 MDNode::deleteTemporary(Dummy);
235 return map(VM, Node, NewMD);
238 // No operands needed remapping. Use an identity mapping.
240 MDNode::deleteTemporary(Dummy);
241 return const_cast<Metadata *>(MD);
244 Metadata *llvm::MapValue(const Metadata *MD, ValueToValueMapTy &VM,
245 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
246 ValueMaterializer *Materializer) {
247 Metadata *NewMD = MapValueImpl(MD, VM, Flags, TypeMapper, Materializer);
248 if (NewMD && NewMD != MD)
249 if (auto *G = dyn_cast<GenericMDNode>(NewMD))
254 MDNode *llvm::MapValue(const MDNode *MD, ValueToValueMapTy &VM,
255 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
256 ValueMaterializer *Materializer) {
257 return cast<MDNode>(MapValue(static_cast<const Metadata *>(MD), VM, Flags,
258 TypeMapper, Materializer));
261 /// RemapInstruction - Convert the instruction operands from referencing the
262 /// current values into those specified by VMap.
264 void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
265 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
266 ValueMaterializer *Materializer){
268 for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
269 Value *V = MapValue(*op, VMap, Flags, TypeMapper, Materializer);
270 // If we aren't ignoring missing entries, assert that something happened.
274 assert((Flags & RF_IgnoreMissingEntries) &&
275 "Referenced value not in value map!");
278 // Remap phi nodes' incoming blocks.
279 if (PHINode *PN = dyn_cast<PHINode>(I)) {
280 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
281 Value *V = MapValue(PN->getIncomingBlock(i), VMap, Flags);
282 // If we aren't ignoring missing entries, assert that something happened.
284 PN->setIncomingBlock(i, cast<BasicBlock>(V));
286 assert((Flags & RF_IgnoreMissingEntries) &&
287 "Referenced block not in value map!");
291 // Remap attached metadata.
292 SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
293 I->getAllMetadata(MDs);
294 for (SmallVectorImpl<std::pair<unsigned, MDNode *>>::iterator
298 MDNode *Old = MI->second;
299 MDNode *New = MapValue(Old, VMap, Flags, TypeMapper, Materializer);
301 I->setMetadata(MI->first, New);
304 // If the instruction's type is being remapped, do so now.
306 I->mutateType(TypeMapper->remapType(I->getType()));