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/Metadata.h"
20 #include "llvm/ADT/SmallVector.h"
23 Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM,
25 ValueToValueMapTy::iterator I = VM.find(V);
27 // If the value already exists in the map, use it.
28 if (I != VM.end() && I->second) return I->second;
30 // Global values do not need to be seeded into the VM if they
31 // are using the identity mapping.
32 if (isa<GlobalValue>(V) || isa<InlineAsm>(V) || isa<MDString>(V))
33 return VM[V] = const_cast<Value*>(V);
35 if (const MDNode *MD = dyn_cast<MDNode>(V)) {
36 // If this is a module-level metadata and we know that nothing at the module
37 // level is changing, then use an identity mapping.
38 if (!MD->isFunctionLocal() && (Flags & RF_NoModuleLevelChanges))
39 return VM[V] = const_cast<Value*>(V);
41 // Check all operands to see if any need to be remapped.
42 for (unsigned i = 0, e = MD->getNumOperands(); i != e; ++i) {
43 Value *OP = MD->getOperand(i);
44 if (OP == 0 || MapValue(OP, VM, Flags) == OP) continue;
46 // Ok, at least one operand needs remapping. Create a dummy node in case
47 // we have a metadata cycle.
48 MDNode *Dummy = MDNode::getTemporary(V->getContext(), 0, 0);
50 SmallVector<Value*, 4> Elts;
51 Elts.reserve(MD->getNumOperands());
52 for (i = 0; i != e; ++i) {
53 Value *Op = MD->getOperand(i);
54 Elts.push_back(Op ? MapValue(Op, VM, Flags) : 0);
56 MDNode *NewMD = MDNode::get(V->getContext(), Elts.data(), Elts.size());
57 Dummy->replaceAllUsesWith(NewMD);
58 MDNode::deleteTemporary(Dummy);
62 // No operands needed remapping. Use an identity mapping.
63 return VM[V] = const_cast<Value*>(V);
66 // Okay, this either must be a constant (which may or may not be mappable) or
67 // is something that is not in the mapping table.
68 Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V));
72 if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
73 Function *F = cast<Function>(MapValue(BA->getFunction(), VM, Flags));
74 BasicBlock *BB = cast_or_null<BasicBlock>(MapValue(BA->getBasicBlock(), VM,
76 return VM[V] = BlockAddress::get(F, BB ? BB : BA->getBasicBlock());
79 for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i) {
80 Value *Op = C->getOperand(i);
81 Value *Mapped = MapValue(Op, VM, Flags);
82 if (Mapped == C) continue;
84 // Okay, the operands don't all match. We've already processed some or all
85 // of the operands, set them up now.
86 std::vector<Constant*> Ops;
87 Ops.reserve(C->getNumOperands());
88 for (unsigned j = 0; j != i; ++j)
89 Ops.push_back(cast<Constant>(C->getOperand(i)));
90 Ops.push_back(cast<Constant>(Mapped));
92 // Map the rest of the operands that aren't processed yet.
93 for (++i; i != e; ++i)
94 Ops.push_back(cast<Constant>(MapValue(C->getOperand(i), VM, Flags)));
96 if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
97 return VM[V] = CE->getWithOperands(Ops);
98 if (ConstantArray *CA = dyn_cast<ConstantArray>(C))
99 return VM[V] = ConstantArray::get(CA->getType(), Ops);
100 if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C))
101 return VM[V] = ConstantStruct::get(CS->getType(), Ops);
102 assert(isa<ConstantVector>(C) && "Unknown mapped constant type");
103 return VM[V] = ConstantVector::get(Ops);
106 // If we reach here, all of the operands of the constant match.
110 /// RemapInstruction - Convert the instruction operands from referencing the
111 /// current values into those specified by VMap.
113 void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
116 for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
117 Value *V = MapValue(*op, VMap, Flags);
118 // If we aren't ignoring missing entries, assert that something happened.
122 assert((Flags & RF_IgnoreMissingEntries) &&
123 "Referenced value not in value map!");
126 // Remap attached metadata.
127 SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
128 I->getAllMetadata(MDs);
129 for (SmallVectorImpl<std::pair<unsigned, MDNode *> >::iterator
130 MI = MDs.begin(), ME = MDs.end(); MI != ME; ++MI) {
131 Value *Old = MI->second;
132 Value *New = MapValue(Old, VMap, Flags);
134 I->setMetadata(MI->first, cast<MDNode>(New));