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() {}
26 Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM, RemapFlags Flags,
27 ValueMapTypeRemapper *TypeMapper) {
28 ValueToValueMapTy::iterator I = VM.find(V);
30 // If the value already exists in the map, use it.
31 if (I != VM.end() && I->second) return I->second;
33 // Global values do not need to be seeded into the VM if they
34 // are using the identity mapping.
35 if (isa<GlobalValue>(V) || isa<MDString>(V))
36 return VM[V] = const_cast<Value*>(V);
38 if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
39 // Inline asm may need *type* remapping.
40 FunctionType *NewTy = IA->getFunctionType();
42 NewTy = cast<FunctionType>(TypeMapper->remapType(NewTy));
44 if (NewTy != IA->getFunctionType())
45 V = InlineAsm::get(NewTy, IA->getAsmString(), IA->getConstraintString(),
46 IA->hasSideEffects(), IA->isAlignStack());
49 return VM[V] = const_cast<Value*>(V);
53 if (const MDNode *MD = dyn_cast<MDNode>(V)) {
54 // If this is a module-level metadata and we know that nothing at the module
55 // level is changing, then use an identity mapping.
56 if (!MD->isFunctionLocal() && (Flags & RF_NoModuleLevelChanges))
57 return VM[V] = const_cast<Value*>(V);
59 // Create a dummy node in case we have a metadata cycle.
60 MDNode *Dummy = MDNode::getTemporary(V->getContext(), ArrayRef<Value*>());
63 // Check all operands to see if any need to be remapped.
64 for (unsigned i = 0, e = MD->getNumOperands(); i != e; ++i) {
65 Value *OP = MD->getOperand(i);
66 if (OP == 0) continue;
67 Value *Mapped_OP = MapValue(OP, VM, Flags, TypeMapper);
68 // If Mapped_Op is null, we should use indentity map.
69 if (Mapped_OP == OP || Mapped_OP == 0) continue;
71 // Ok, at least one operand needs remapping.
72 SmallVector<Value*, 4> Elts;
73 Elts.reserve(MD->getNumOperands());
74 for (i = 0; i != e; ++i) {
75 Value *Op = MD->getOperand(i);
79 Value *Mapped_Op = MapValue(Op, VM, Flags, TypeMapper);
80 // If Mapped_Op is null, we should use indentity map.
81 Elts.push_back(Mapped_Op ? Mapped_Op : Op);
84 MDNode *NewMD = MDNode::get(V->getContext(), Elts);
85 Dummy->replaceAllUsesWith(NewMD);
87 MDNode::deleteTemporary(Dummy);
91 VM[V] = const_cast<Value*>(V);
92 MDNode::deleteTemporary(Dummy);
94 // No operands needed remapping. Use an identity mapping.
95 return const_cast<Value*>(V);
98 // Okay, this either must be a constant (which may or may not be mappable) or
99 // is something that is not in the mapping table.
100 Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V));
104 if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
106 cast<Function>(MapValue(BA->getFunction(), VM, Flags, TypeMapper));
107 BasicBlock *BB = cast_or_null<BasicBlock>(MapValue(BA->getBasicBlock(), VM,
109 return VM[V] = BlockAddress::get(F, BB ? BB : BA->getBasicBlock());
112 // Otherwise, we have some other constant to remap. Start by checking to see
113 // if all operands have an identity remapping.
114 unsigned OpNo = 0, NumOperands = C->getNumOperands();
116 for (; OpNo != NumOperands; ++OpNo) {
117 Value *Op = C->getOperand(OpNo);
118 Mapped = MapValue(Op, VM, Flags, TypeMapper);
119 if (Mapped != C) break;
122 // See if the type mapper wants to remap the type as well.
123 Type *NewTy = C->getType();
125 NewTy = TypeMapper->remapType(NewTy);
127 // If the result type and all operands match up, then just insert an identity
129 if (OpNo == NumOperands && NewTy == C->getType())
132 // Okay, we need to create a new constant. We've already processed some or
133 // all of the operands, set them all up now.
134 SmallVector<Constant*, 8> Ops;
135 Ops.reserve(NumOperands);
136 for (unsigned j = 0; j != OpNo; ++j)
137 Ops.push_back(cast<Constant>(C->getOperand(j)));
139 // If one of the operands mismatch, push it and the other mapped operands.
140 if (OpNo != NumOperands) {
141 Ops.push_back(cast<Constant>(Mapped));
143 // Map the rest of the operands that aren't processed yet.
144 for (++OpNo; OpNo != NumOperands; ++OpNo)
145 Ops.push_back(MapValue(cast<Constant>(C->getOperand(OpNo)), VM,
149 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
150 return VM[V] = CE->getWithOperands(Ops, NewTy);
151 if (isa<ConstantArray>(C))
152 return VM[V] = ConstantArray::get(cast<ArrayType>(NewTy), Ops);
153 if (isa<ConstantStruct>(C))
154 return VM[V] = ConstantStruct::get(cast<StructType>(NewTy), Ops);
155 if (isa<ConstantVector>(C))
156 return VM[V] = ConstantVector::get(Ops);
157 // If this is a no-operand constant, it must be because the type was remapped.
158 if (isa<UndefValue>(C))
159 return VM[V] = UndefValue::get(NewTy);
160 if (isa<ConstantAggregateZero>(C))
161 return VM[V] = ConstantAggregateZero::get(NewTy);
162 assert(isa<ConstantPointerNull>(C));
163 return VM[V] = ConstantPointerNull::get(cast<PointerType>(NewTy));
166 /// RemapInstruction - Convert the instruction operands from referencing the
167 /// current values into those specified by VMap.
169 void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
170 RemapFlags Flags, ValueMapTypeRemapper *TypeMapper){
172 for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
173 Value *V = MapValue(*op, VMap, Flags, TypeMapper);
174 // If we aren't ignoring missing entries, assert that something happened.
178 assert((Flags & RF_IgnoreMissingEntries) &&
179 "Referenced value not in value map!");
182 // Remap phi nodes' incoming blocks.
183 if (PHINode *PN = dyn_cast<PHINode>(I)) {
184 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
185 Value *V = MapValue(PN->getIncomingBlock(i), VMap, Flags);
186 // If we aren't ignoring missing entries, assert that something happened.
188 PN->setIncomingBlock(i, cast<BasicBlock>(V));
190 assert((Flags & RF_IgnoreMissingEntries) &&
191 "Referenced block not in value map!");
195 // Remap attached metadata.
196 SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
197 I->getAllMetadata(MDs);
198 for (SmallVectorImpl<std::pair<unsigned, MDNode *> >::iterator
199 MI = MDs.begin(), ME = MDs.end(); MI != ME; ++MI) {
200 MDNode *Old = MI->second;
201 MDNode *New = MapValue(Old, VMap, Flags, TypeMapper);
203 I->setMetadata(MI->first, New);
206 // If the instruction's type is being remapped, do so now.
208 I->mutateType(TypeMapper->remapType(I->getType()));