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/Type.h"
17 #include "llvm/Constants.h"
18 #include "llvm/Function.h"
19 #include "llvm/Instructions.h"
20 #include "llvm/Metadata.h"
21 #include "llvm/ADT/SmallVector.h"
24 Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM,
26 ValueToValueMapTy::iterator I = VM.find(V);
28 // If the value already exists in the map, use it.
29 if (I != VM.end() && I->second) return I->second;
31 // Global values do not need to be seeded into the VM if they
32 // are using the identity mapping.
33 if (isa<GlobalValue>(V) || isa<InlineAsm>(V) || isa<MDString>(V))
34 return VM[V] = const_cast<Value*>(V);
36 if (const MDNode *MD = dyn_cast<MDNode>(V)) {
37 // If this is a module-level metadata and we know that nothing at the module
38 // level is changing, then use an identity mapping.
39 if (!MD->isFunctionLocal() && (Flags & RF_NoModuleLevelChanges))
40 return VM[V] = const_cast<Value*>(V);
42 // Create a dummy node in case we have a metadata cycle.
43 MDNode *Dummy = MDNode::getTemporary(V->getContext(), ArrayRef<Value*>());
46 // Check all operands to see if any need to be remapped.
47 for (unsigned i = 0, e = MD->getNumOperands(); i != e; ++i) {
48 Value *OP = MD->getOperand(i);
49 if (OP == 0 || MapValue(OP, VM, Flags) == OP) continue;
51 // Ok, at least one operand needs remapping.
52 SmallVector<Value*, 4> Elts;
53 Elts.reserve(MD->getNumOperands());
54 for (i = 0; i != e; ++i) {
55 Value *Op = MD->getOperand(i);
56 Elts.push_back(Op ? MapValue(Op, VM, Flags) : 0);
58 MDNode *NewMD = MDNode::get(V->getContext(), Elts);
59 Dummy->replaceAllUsesWith(NewMD);
61 MDNode::deleteTemporary(Dummy);
65 VM[V] = const_cast<Value*>(V);
66 MDNode::deleteTemporary(Dummy);
68 // No operands needed remapping. Use an identity mapping.
69 return const_cast<Value*>(V);
72 // Okay, this either must be a constant (which may or may not be mappable) or
73 // is something that is not in the mapping table.
74 Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V));
78 if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
79 Function *F = cast<Function>(MapValue(BA->getFunction(), VM, Flags));
80 BasicBlock *BB = cast_or_null<BasicBlock>(MapValue(BA->getBasicBlock(), VM,
82 return VM[V] = BlockAddress::get(F, BB ? BB : BA->getBasicBlock());
85 for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i) {
86 Value *Op = C->getOperand(i);
87 Value *Mapped = MapValue(Op, VM, Flags);
88 if (Mapped == C) continue;
90 // Okay, the operands don't all match. We've already processed some or all
91 // of the operands, set them up now.
92 std::vector<Constant*> Ops;
93 Ops.reserve(C->getNumOperands());
94 for (unsigned j = 0; j != i; ++j)
95 Ops.push_back(cast<Constant>(C->getOperand(i)));
96 Ops.push_back(cast<Constant>(Mapped));
98 // Map the rest of the operands that aren't processed yet.
99 for (++i; i != e; ++i)
100 Ops.push_back(cast<Constant>(MapValue(C->getOperand(i), VM, Flags)));
102 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
103 return VM[V] = CE->getWithOperands(Ops);
104 if (ConstantArray *CA = dyn_cast<ConstantArray>(C))
105 return VM[V] = ConstantArray::get(CA->getType(), Ops);
106 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C))
107 return VM[V] = ConstantStruct::get(CS->getType(), Ops);
108 assert(isa<ConstantVector>(C) && "Unknown mapped constant type");
109 return VM[V] = ConstantVector::get(Ops);
112 // If we reach here, all of the operands of the constant match.
116 /// RemapInstruction - Convert the instruction operands from referencing the
117 /// current values into those specified by VMap.
119 void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
122 for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
123 Value *V = MapValue(*op, VMap, Flags);
124 // If we aren't ignoring missing entries, assert that something happened.
128 assert((Flags & RF_IgnoreMissingEntries) &&
129 "Referenced value not in value map!");
132 // Remap phi nodes' incoming blocks.
133 if (PHINode *PN = dyn_cast<PHINode>(I)) {
134 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
135 Value *V = MapValue(PN->getIncomingBlock(i), VMap, Flags);
136 // If we aren't ignoring missing entries, assert that something happened.
138 PN->setIncomingBlock(i, cast<BasicBlock>(V));
140 assert((Flags & RF_IgnoreMissingEntries) &&
141 "Referenced block not in value map!");
145 // Remap attached metadata.
146 SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
147 I->getAllMetadata(MDs);
148 for (SmallVectorImpl<std::pair<unsigned, MDNode *> >::iterator
149 MI = MDs.begin(), ME = MDs.end(); MI != ME; ++MI) {
150 Value *Old = MI->second;
151 Value *New = MapValue(Old, VMap, Flags);
153 I->setMetadata(MI->first, cast<MDNode>(New));