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//===- ValueMapper.cpp - Interface shared by lib/Transforms/Utils ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the MapValue function, which is shared by various parts of
// the lib/Transforms/Utils library.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/ValueMapper.h"
#include "llvm/Type.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/Metadata.h"
#include "llvm/ADT/SmallVector.h"
using namespace llvm;
Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM,
RemapFlags Flags) {
ValueToValueMapTy::iterator I = VM.find(V);
// If the value already exists in the map, use it.
if (I != VM.end() && I->second) return I->second;
// Global values do not need to be seeded into the VM if they
// are using the identity mapping.
if (isa<GlobalValue>(V) || isa<InlineAsm>(V) || isa<MDString>(V))
return VM[V] = const_cast<Value*>(V);
if (const MDNode *MD = dyn_cast<MDNode>(V)) {
// If this is a module-level metadata and we know that nothing at the module
// level is changing, then use an identity mapping.
if (!MD->isFunctionLocal() && (Flags & RF_NoModuleLevelChanges))
return VM[V] = const_cast<Value*>(V);
// Create a dummy node in case we have a metadata cycle.
MDNode *Dummy = MDNode::getTemporary(V->getContext(), 0, 0);
VM[V] = Dummy;
// Check all operands to see if any need to be remapped.
for (unsigned i = 0, e = MD->getNumOperands(); i != e; ++i) {
Value *OP = MD->getOperand(i);
if (OP == 0 || MapValue(OP, VM, Flags) == OP) continue;
// Ok, at least one operand needs remapping.
SmallVector<Value*, 4> Elts;
Elts.reserve(MD->getNumOperands());
for (i = 0; i != e; ++i) {
Value *Op = MD->getOperand(i);
Elts.push_back(Op ? MapValue(Op, VM, Flags) : 0);
}
MDNode *NewMD = MDNode::get(V->getContext(), Elts.data(), Elts.size());
Dummy->replaceAllUsesWith(NewMD);
VM[V] = NewMD;
MDNode::deleteTemporary(Dummy);
return NewMD;
}
VM[V] = const_cast<Value*>(V);
MDNode::deleteTemporary(Dummy);
// No operands needed remapping. Use an identity mapping.
return const_cast<Value*>(V);
}
// Okay, this either must be a constant (which may or may not be mappable) or
// is something that is not in the mapping table.
Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V));
if (C == 0)
return 0;
if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
Function *F = cast<Function>(MapValue(BA->getFunction(), VM, Flags));
BasicBlock *BB = cast_or_null<BasicBlock>(MapValue(BA->getBasicBlock(), VM,
Flags));
return VM[V] = BlockAddress::get(F, BB ? BB : BA->getBasicBlock());
}
for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i) {
Value *Op = C->getOperand(i);
Value *Mapped = MapValue(Op, VM, Flags);
if (Mapped == C) continue;
// Okay, the operands don't all match. We've already processed some or all
// of the operands, set them up now.
std::vector<Constant*> Ops;
Ops.reserve(C->getNumOperands());
for (unsigned j = 0; j != i; ++j)
Ops.push_back(cast<Constant>(C->getOperand(i)));
Ops.push_back(cast<Constant>(Mapped));
// Map the rest of the operands that aren't processed yet.
for (++i; i != e; ++i)
Ops.push_back(cast<Constant>(MapValue(C->getOperand(i), VM, Flags)));
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
return VM[V] = CE->getWithOperands(Ops);
if (ConstantArray *CA = dyn_cast<ConstantArray>(C))
return VM[V] = ConstantArray::get(CA->getType(), Ops);
if (ConstantStruct *CS = dyn_cast<ConstantStruct>(C))
return VM[V] = ConstantStruct::get(CS->getType(), Ops);
assert(isa<ConstantVector>(C) && "Unknown mapped constant type");
return VM[V] = ConstantVector::get(Ops);
}
// If we reach here, all of the operands of the constant match.
return VM[V] = C;
}
/// RemapInstruction - Convert the instruction operands from referencing the
/// current values into those specified by VMap.
///
void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
RemapFlags Flags) {
// Remap operands.
for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
Value *V = MapValue(*op, VMap, Flags);
// If we aren't ignoring missing entries, assert that something happened.
if (V != 0)
*op = V;
else
assert((Flags & RF_IgnoreMissingEntries) &&
"Referenced value not in value map!");
}
// Remap attached metadata.
SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
I->getAllMetadata(MDs);
for (SmallVectorImpl<std::pair<unsigned, MDNode *> >::iterator
MI = MDs.begin(), ME = MDs.end(); MI != ME; ++MI) {
Value *Old = MI->second;
Value *New = MapValue(Old, VMap, Flags);
if (New != Old)
I->setMetadata(MI->first, cast<MDNode>(New));
}
}
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