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llvm-project/llvm/lib/Transforms/Utils/ValueMapper.cpp

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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/IR/CallSite.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Operator.h"
using namespace llvm;
// Out of line method to get vtable etc for class.
void ValueMapTypeRemapper::anchor() {}
void ValueMaterializer::anchor() {}
Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
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;
// If we have a materializer and it can materialize a value, use that.
if (Materializer) {
if (Value *NewV = Materializer->materializeValueFor(const_cast<Value*>(V)))
return VM[V] = NewV;
}
// Global values do not need to be seeded into the VM if they
// are using the identity mapping.
if (isa<GlobalValue>(V))
return VM[V] = const_cast<Value*>(V);
if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
// Inline asm may need *type* remapping.
FunctionType *NewTy = IA->getFunctionType();
if (TypeMapper) {
NewTy = cast<FunctionType>(TypeMapper->remapType(NewTy));
if (NewTy != IA->getFunctionType())
V = InlineAsm::get(NewTy, IA->getAsmString(), IA->getConstraintString(),
IA->hasSideEffects(), IA->isAlignStack());
}
return VM[V] = const_cast<Value*>(V);
}
if (const auto *MDV = dyn_cast<MetadataAsValue>(V)) {
const Metadata *MD = MDV->getMetadata();
// If this is a module-level metadata and we know that nothing at the module
// level is changing, then use an identity mapping.
if (!isa<LocalAsMetadata>(MD) && (Flags & RF_NoModuleLevelChanges))
return VM[V] = const_cast<Value *>(V);
auto *MappedMD = MapMetadata(MD, VM, Flags, TypeMapper, Materializer);
if (MD == MappedMD || (!MappedMD && (Flags & RF_IgnoreMissingEntries)))
return VM[V] = const_cast<Value *>(V);
// FIXME: This assert crashes during bootstrap, but I think it should be
// correct. For now, just match behaviour from before the metadata/value
// split.
//
// assert(MappedMD && "Referenced metadata value not in value map");
return VM[V] = MetadataAsValue::get(V->getContext(), MappedMD);
}
// 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)
return nullptr;
if (BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
Function *F =
cast<Function>(MapValue(BA->getFunction(), VM, Flags, TypeMapper, Materializer));
BasicBlock *BB = cast_or_null<BasicBlock>(MapValue(BA->getBasicBlock(), VM,
Flags, TypeMapper, Materializer));
return VM[V] = BlockAddress::get(F, BB ? BB : BA->getBasicBlock());
}
// Otherwise, we have some other constant to remap. Start by checking to see
// if all operands have an identity remapping.
unsigned OpNo = 0, NumOperands = C->getNumOperands();
Value *Mapped = nullptr;
for (; OpNo != NumOperands; ++OpNo) {
Value *Op = C->getOperand(OpNo);
Mapped = MapValue(Op, VM, Flags, TypeMapper, Materializer);
if (Mapped != C) break;
}
// See if the type mapper wants to remap the type as well.
Type *NewTy = C->getType();
if (TypeMapper)
NewTy = TypeMapper->remapType(NewTy);
// If the result type and all operands match up, then just insert an identity
// mapping.
if (OpNo == NumOperands && NewTy == C->getType())
return VM[V] = C;
// Okay, we need to create a new constant. We've already processed some or
// all of the operands, set them all up now.
SmallVector<Constant*, 8> Ops;
Ops.reserve(NumOperands);
for (unsigned j = 0; j != OpNo; ++j)
Ops.push_back(cast<Constant>(C->getOperand(j)));
// If one of the operands mismatch, push it and the other mapped operands.
if (OpNo != NumOperands) {
Ops.push_back(cast<Constant>(Mapped));
// Map the rest of the operands that aren't processed yet.
for (++OpNo; OpNo != NumOperands; ++OpNo)
Ops.push_back(MapValue(cast<Constant>(C->getOperand(OpNo)), VM,
Flags, TypeMapper, Materializer));
}
Type *NewSrcTy = nullptr;
if (TypeMapper)
if (auto *GEPO = dyn_cast<GEPOperator>(C))
NewSrcTy = TypeMapper->remapType(GEPO->getSourceElementType());
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
return VM[V] = CE->getWithOperands(Ops, NewTy, false, NewSrcTy);
if (isa<ConstantArray>(C))
return VM[V] = ConstantArray::get(cast<ArrayType>(NewTy), Ops);
if (isa<ConstantStruct>(C))
return VM[V] = ConstantStruct::get(cast<StructType>(NewTy), Ops);
if (isa<ConstantVector>(C))
return VM[V] = ConstantVector::get(Ops);
// If this is a no-operand constant, it must be because the type was remapped.
if (isa<UndefValue>(C))
return VM[V] = UndefValue::get(NewTy);
if (isa<ConstantAggregateZero>(C))
return VM[V] = ConstantAggregateZero::get(NewTy);
assert(isa<ConstantPointerNull>(C));
return VM[V] = ConstantPointerNull::get(cast<PointerType>(NewTy));
}
static Metadata *mapToMetadata(ValueToValueMapTy &VM, const Metadata *Key,
Metadata *Val) {
VM.MD()[Key].reset(Val);
return Val;
}
static Metadata *mapToSelf(ValueToValueMapTy &VM, const Metadata *MD) {
return mapToMetadata(VM, MD, const_cast<Metadata *>(MD));
}
static Metadata *MapMetadataImpl(const Metadata *MD,
SmallVectorImpl<MDNode *> &DistinctWorklist,
ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer);
static Metadata *mapMetadataOp(Metadata *Op,
SmallVectorImpl<MDNode *> &DistinctWorklist,
ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
if (!Op)
return nullptr;
if (Metadata *MappedOp = MapMetadataImpl(Op, DistinctWorklist, VM, Flags,
TypeMapper, Materializer))
return MappedOp;
// Use identity map if MappedOp is null and we can ignore missing entries.
if (Flags & RF_IgnoreMissingEntries)
return Op;
// FIXME: This assert crashes during bootstrap, but I think it should be
// correct. For now, just match behaviour from before the metadata/value
// split.
//
// llvm_unreachable("Referenced metadata not in value map!");
return nullptr;
}
/// Resolve uniquing cycles involving the given metadata.
static void resolveCycles(Metadata *MD) {
if (auto *N = dyn_cast_or_null<MDNode>(MD))
if (!N->isResolved())
N->resolveCycles();
}
/// Remap the operands of an MDNode.
///
/// If \c Node is temporary, uniquing cycles are ignored. If \c Node is
/// distinct, uniquing cycles are resolved as they're found.
///
/// \pre \c Node.isDistinct() or \c Node.isTemporary().
static bool remapOperands(MDNode &Node,
SmallVectorImpl<MDNode *> &DistinctWorklist,
ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
assert(!Node.isUniqued() && "Expected temporary or distinct node");
const bool IsDistinct = Node.isDistinct();
bool AnyChanged = false;
for (unsigned I = 0, E = Node.getNumOperands(); I != E; ++I) {
Metadata *Old = Node.getOperand(I);
Metadata *New = mapMetadataOp(Old, DistinctWorklist, VM, Flags, TypeMapper,
Materializer);
if (Old != New) {
AnyChanged = true;
Node.replaceOperandWith(I, New);
// Resolve uniquing cycles underneath distinct nodes on the fly so they
// don't infect later operands.
if (IsDistinct)
resolveCycles(New);
}
}
return AnyChanged;
}
/// Map a distinct MDNode.
///
/// Whether distinct nodes change is independent of their operands. If \a
/// RF_MoveDistinctMDs, then they are reused, and their operands remapped in
/// place; effectively, they're moved from one graph to another. Otherwise,
/// they're cloned/duplicated, and the new copy's operands are remapped.
static Metadata *mapDistinctNode(const MDNode *Node,
SmallVectorImpl<MDNode *> &DistinctWorklist,
ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
assert(Node->isDistinct() && "Expected distinct node");
MDNode *NewMD;
if (Flags & RF_MoveDistinctMDs)
NewMD = const_cast<MDNode *>(Node);
else
NewMD = MDNode::replaceWithDistinct(Node->clone());
// Remap operands later.
DistinctWorklist.push_back(NewMD);
return mapToMetadata(VM, Node, NewMD);
}
/// \brief Map a uniqued MDNode.
///
/// Uniqued nodes may not need to be recreated (they may map to themselves).
static Metadata *mapUniquedNode(const MDNode *Node,
SmallVectorImpl<MDNode *> &DistinctWorklist,
ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
assert(Node->isUniqued() && "Expected uniqued node");
// Create a temporary node and map it upfront in case we have a uniquing
// cycle. If necessary, this mapping will get updated by RAUW logic before
// returning.
auto ClonedMD = Node->clone();
mapToMetadata(VM, Node, ClonedMD.get());
if (!remapOperands(*ClonedMD, DistinctWorklist, VM, Flags, TypeMapper,
Materializer)) {
// No operands changed, so use the original.
ClonedMD->replaceAllUsesWith(const_cast<MDNode *>(Node));
return const_cast<MDNode *>(Node);
}
// Uniquify the cloned node.
return MDNode::replaceWithUniqued(std::move(ClonedMD));
}
static Metadata *MapMetadataImpl(const Metadata *MD,
SmallVectorImpl<MDNode *> &DistinctWorklist,
ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
// If the value already exists in the map, use it.
if (Metadata *NewMD = VM.MD().lookup(MD).get())
return NewMD;
if (isa<MDString>(MD))
return mapToSelf(VM, MD);
if (isa<ConstantAsMetadata>(MD))
if ((Flags & RF_NoModuleLevelChanges))
return mapToSelf(VM, MD);
if (const auto *VMD = dyn_cast<ValueAsMetadata>(MD)) {
Value *MappedV =
MapValue(VMD->getValue(), VM, Flags, TypeMapper, Materializer);
if (VMD->getValue() == MappedV ||
(!MappedV && (Flags & RF_IgnoreMissingEntries)))
return mapToSelf(VM, MD);
// FIXME: This assert crashes during bootstrap, but I think it should be
// correct. For now, just match behaviour from before the metadata/value
// split.
//
// assert(MappedV && "Referenced metadata not in value map!");
if (MappedV)
return mapToMetadata(VM, MD, ValueAsMetadata::get(MappedV));
return nullptr;
}
// Note: this cast precedes the Flags check so we always get its associated
// assertion.
const MDNode *Node = cast<MDNode>(MD);
// If this is a module-level metadata and we know that nothing at the
// module level is changing, then use an identity mapping.
if (Flags & RF_NoModuleLevelChanges)
return mapToSelf(VM, MD);
// Require resolved nodes whenever metadata might be remapped.
assert(Node->isResolved() && "Unexpected unresolved node");
if (Node->isDistinct())
return mapDistinctNode(Node, DistinctWorklist, VM, Flags, TypeMapper,
Materializer);
return mapUniquedNode(Node, DistinctWorklist, VM, Flags, TypeMapper,
Materializer);
}
Metadata *llvm::MapMetadata(const Metadata *MD, ValueToValueMapTy &VM,
RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
SmallVector<MDNode *, 8> DistinctWorklist;
Metadata *NewMD = MapMetadataImpl(MD, DistinctWorklist, VM, Flags, TypeMapper,
Materializer);
// When there are no module-level changes, it's possible that the metadata
// graph has temporaries. Skip the logic to resolve cycles, since it's
// unnecessary (and invalid) in that case.
if (Flags & RF_NoModuleLevelChanges)
return NewMD;
// Resolve cycles involving the entry metadata.
resolveCycles(NewMD);
// Remap the operands of distinct MDNodes.
while (!DistinctWorklist.empty())
remapOperands(*DistinctWorklist.pop_back_val(), DistinctWorklist, VM, Flags,
TypeMapper, Materializer);
return NewMD;
}
MDNode *llvm::MapMetadata(const MDNode *MD, ValueToValueMapTy &VM,
RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer) {
return cast<MDNode>(MapMetadata(static_cast<const Metadata *>(MD), VM, Flags,
TypeMapper, Materializer));
}
/// RemapInstruction - Convert the instruction operands from referencing the
/// current values into those specified by VMap.
///
void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer){
// Remap operands.
for (User::op_iterator op = I->op_begin(), E = I->op_end(); op != E; ++op) {
Value *V = MapValue(*op, VMap, Flags, TypeMapper, Materializer);
// If we aren't ignoring missing entries, assert that something happened.
if (V)
*op = V;
else
assert((Flags & RF_IgnoreMissingEntries) &&
"Referenced value not in value map!");
}
// Remap phi nodes' incoming blocks.
if (PHINode *PN = dyn_cast<PHINode>(I)) {
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
Value *V = MapValue(PN->getIncomingBlock(i), VMap, Flags);
// If we aren't ignoring missing entries, assert that something happened.
if (V)
PN->setIncomingBlock(i, cast<BasicBlock>(V));
else
assert((Flags & RF_IgnoreMissingEntries) &&
"Referenced block not in value map!");
}
}
// Remap attached metadata.
SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
I->getAllMetadata(MDs);
for (const auto &MI : MDs) {
MDNode *Old = MI.second;
MDNode *New = MapMetadata(Old, VMap, Flags, TypeMapper, Materializer);
if (New != Old)
I->setMetadata(MI.first, New);
}
if (!TypeMapper)
return;
// If the instruction's type is being remapped, do so now.
if (auto CS = CallSite(I)) {
SmallVector<Type *, 3> Tys;
FunctionType *FTy = CS.getFunctionType();
Tys.reserve(FTy->getNumParams());
for (Type *Ty : FTy->params())
Tys.push_back(TypeMapper->remapType(Ty));
CS.mutateFunctionType(FunctionType::get(
TypeMapper->remapType(I->getType()), Tys, FTy->isVarArg()));
return;
}
if (auto *AI = dyn_cast<AllocaInst>(I))
AI->setAllocatedType(TypeMapper->remapType(AI->getAllocatedType()));
if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) {
GEP->setSourceElementType(
TypeMapper->remapType(GEP->getSourceElementType()));
GEP->setResultElementType(
TypeMapper->remapType(GEP->getResultElementType()));
}
I->mutateType(TypeMapper->remapType(I->getType()));
}
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