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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/ADT/DenseSet.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalVariable.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() {}
namespace {
/// A basic block used in a BlockAddress whose function body is not yet
/// materialized.
struct DelayedBasicBlock {
BasicBlock *OldBB;
std::unique_ptr<BasicBlock> TempBB;
DelayedBasicBlock(const BlockAddress &Old)
: OldBB(Old.getBasicBlock()),
TempBB(BasicBlock::Create(Old.getContext())) {}
};
struct WorklistEntry {
enum EntryKind {
MapGlobalInit,
MapAppendingVar,
MapGlobalAliasee,
RemapFunction
};
struct GVInitTy {
GlobalVariable *GV;
Constant *Init;
};
struct AppendingGVTy {
GlobalVariable *GV;
Constant *InitPrefix;
};
struct GlobalAliaseeTy {
GlobalAlias *GA;
Constant *Aliasee;
};
unsigned Kind : 2;
unsigned MCID : 29;
unsigned AppendingGVIsOldCtorDtor : 1;
unsigned AppendingGVNumNewMembers;
union {
GVInitTy GVInit;
AppendingGVTy AppendingGV;
GlobalAliaseeTy GlobalAliasee;
Function *RemapF;
} Data;
};
struct MappingContext {
ValueToValueMapTy *VM;
ValueMaterializer *Materializer = nullptr;
/// Construct a MappingContext with a value map and materializer.
explicit MappingContext(ValueToValueMapTy &VM,
ValueMaterializer *Materializer = nullptr)
: VM(&VM), Materializer(Materializer) {}
};
class MDNodeMapper;
class Mapper {
friend class MDNodeMapper;
#ifndef NDEBUG
DenseSet<GlobalValue *> AlreadyScheduled;
#endif
RemapFlags Flags;
ValueMapTypeRemapper *TypeMapper;
unsigned CurrentMCID = 0;
SmallVector<MappingContext, 2> MCs;
SmallVector<WorklistEntry, 4> Worklist;
SmallVector<DelayedBasicBlock, 1> DelayedBBs;
SmallVector<Constant *, 16> AppendingInits;
public:
Mapper(ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper, ValueMaterializer *Materializer)
: Flags(Flags), TypeMapper(TypeMapper),
MCs(1, MappingContext(VM, Materializer)) {}
/// ValueMapper should explicitly call \a flush() before destruction.
~Mapper() { assert(!hasWorkToDo() && "Expected to be flushed"); }
bool hasWorkToDo() const { return !Worklist.empty(); }
unsigned
registerAlternateMappingContext(ValueToValueMapTy &VM,
ValueMaterializer *Materializer = nullptr) {
MCs.push_back(MappingContext(VM, Materializer));
return MCs.size() - 1;
}
void addFlags(RemapFlags Flags);
Value *mapValue(const Value *V);
void remapInstruction(Instruction *I);
void remapFunction(Function &F);
Constant *mapConstant(const Constant *C) {
return cast_or_null<Constant>(mapValue(C));
}
/// Map metadata.
///
/// Find the mapping for MD. Guarantees that the return will be resolved
/// (not an MDNode, or MDNode::isResolved() returns true).
Metadata *mapMetadata(const Metadata *MD);
void scheduleMapGlobalInitializer(GlobalVariable &GV, Constant &Init,
unsigned MCID);
void scheduleMapAppendingVariable(GlobalVariable &GV, Constant *InitPrefix,
bool IsOldCtorDtor,
ArrayRef<Constant *> NewMembers,
unsigned MCID);
void scheduleMapGlobalAliasee(GlobalAlias &GA, Constant &Aliasee,
unsigned MCID);
void scheduleRemapFunction(Function &F, unsigned MCID);
void flush();
private:
void mapGlobalInitializer(GlobalVariable &GV, Constant &Init);
void mapAppendingVariable(GlobalVariable &GV, Constant *InitPrefix,
bool IsOldCtorDtor,
ArrayRef<Constant *> NewMembers);
void mapGlobalAliasee(GlobalAlias &GA, Constant &Aliasee);
void remapFunction(Function &F, ValueToValueMapTy &VM);
ValueToValueMapTy &getVM() { return *MCs[CurrentMCID].VM; }
ValueMaterializer *getMaterializer() { return MCs[CurrentMCID].Materializer; }
Value *mapBlockAddress(const BlockAddress &BA);
/// Map metadata that doesn't require visiting operands.
Optional<Metadata *> mapSimpleMetadata(const Metadata *MD);
Metadata *mapToMetadata(const Metadata *Key, Metadata *Val);
Metadata *mapToSelf(const Metadata *MD);
};
class MDNodeMapper {
Mapper &M;
/// Data about a node in \a UniquedGraph.
struct Data {
bool HasChanged = false;
unsigned ID = ~0u;
TempMDNode Placeholder;
};
/// A graph of uniqued nodes.
struct UniquedGraph {
SmallDenseMap<const Metadata *, Data, 32> Info; // Node properties.
SmallVector<MDNode *, 16> POT; // Post-order traversal.
/// Propagate changed operands through the post-order traversal.
///
/// Iteratively update \a Data::HasChanged for each node based on \a
/// Data::HasChanged of its operands, until fixed point.
void propagateChanges();
/// Get a forward reference to a node to use as an operand.
Metadata &getFwdReference(MDNode &Op);
};
/// Worklist of distinct nodes whose operands need to be remapped.
SmallVector<MDNode *, 16> DistinctWorklist;
// Storage for a UniquedGraph.
SmallDenseMap<const Metadata *, Data, 32> InfoStorage;
SmallVector<MDNode *, 16> POTStorage;
public:
MDNodeMapper(Mapper &M) : M(M) {}
/// Map a metadata node (and its transitive operands).
///
/// Map all the (unmapped) nodes in the subgraph under \c N. The iterative
/// algorithm handles distinct nodes and uniqued node subgraphs using
/// different strategies.
///
/// Distinct nodes are immediately mapped and added to \a DistinctWorklist
/// using \a mapDistinctNode(). Their mapping can always be computed
/// immediately without visiting operands, even if their operands change.
///
/// The mapping for uniqued nodes depends on whether their operands change.
/// \a mapTopLevelUniquedNode() traverses the transitive uniqued subgraph of
/// a node to calculate uniqued node mappings in bulk. Distinct leafs are
/// added to \a DistinctWorklist with \a mapDistinctNode().
///
/// After mapping \c N itself, this function remaps the operands of the
/// distinct nodes in \a DistinctWorklist until the entire subgraph under \c
/// N has been mapped.
Metadata *map(const MDNode &N);
private:
/// Map a top-level uniqued node and the uniqued subgraph underneath it.
///
/// This builds up a post-order traversal of the (unmapped) uniqued subgraph
/// underneath \c FirstN and calculates the nodes' mapping. Each node uses
/// the identity mapping (\a Mapper::mapToSelf()) as long as all of its
/// operands uses the identity mapping.
///
/// The algorithm works as follows:
///
/// 1. \a createPOT(): traverse the uniqued subgraph under \c FirstN and
/// save the post-order traversal in the given \a UniquedGraph, tracking
/// nodes' operands change.
///
/// 2. \a UniquedGraph::propagateChanges(): propagate changed operands
/// through the \a UniquedGraph until fixed point, following the rule
/// that if a node changes, any node that references must also change.
///
/// 3. \a mapNodesInPOT(): map the uniqued nodes, creating new uniqued nodes
/// (referencing new operands) where necessary.
Metadata *mapTopLevelUniquedNode(const MDNode &FirstN);
/// Try to map the operand of an \a MDNode.
///
/// If \c Op is already mapped, return the mapping. If it's not an \a
/// MDNode, compute and return the mapping. If it's a distinct \a MDNode,
/// return the result of \a mapDistinctNode().
///
/// \return None if \c Op is an unmapped uniqued \a MDNode.
/// \post getMappedOp(Op) only returns None if this returns None.
Optional<Metadata *> tryToMapOperand(const Metadata *Op);
/// Map a distinct node.
///
/// Return the mapping for the distinct node \c N, saving the result in \a
/// DistinctWorklist for later remapping.
///
/// \pre \c N is not yet mapped.
/// \pre \c N.isDistinct().
MDNode *mapDistinctNode(const MDNode &N);
/// Get a previously mapped node.
Optional<Metadata *> getMappedOp(const Metadata *Op) const;
/// Create a post-order traversal of an unmapped uniqued node subgraph.
///
/// This traverses the metadata graph deeply enough to map \c FirstN. It
/// uses \a tryToMapOperand() (via \a Mapper::mapSimplifiedNode()), so any
/// metadata that has already been mapped will not be part of the POT.
///
/// Each node that has a changed operand from outside the graph (e.g., a
/// distinct node, an already-mapped uniqued node, or \a ConstantAsMetadata)
/// is marked with \a Data::HasChanged.
///
/// \return \c true if any nodes in \c G have \a Data::HasChanged.
/// \post \c G.POT is a post-order traversal ending with \c FirstN.
/// \post \a Data::hasChanged in \c G.Info indicates whether any node needs
/// to change because of operands outside the graph.
bool createPOT(UniquedGraph &G, const MDNode &FirstN);
/// Visit the operands of a uniqued node in the POT.
///
/// Visit the operands in the range from \c I to \c E, returning the first
/// uniqued node we find that isn't yet in \c G. \c I is always advanced to
/// where to continue the loop through the operands.
///
/// This sets \c HasChanged if any of the visited operands change.
MDNode *visitOperands(UniquedGraph &G, MDNode::op_iterator &I,
MDNode::op_iterator E, bool &HasChanged);
/// Map all the nodes in the given uniqued graph.
///
/// This visits all the nodes in \c G in post-order, using the identity
/// mapping or creating a new node depending on \a Data::HasChanged.
///
/// \pre \a getMappedOp() returns None for nodes in \c G, but not for any of
/// their operands outside of \c G.
/// \pre \a Data::HasChanged is true for a node in \c G iff any of its
/// operands have changed.
/// \post \a getMappedOp() returns the mapped node for every node in \c G.
void mapNodesInPOT(UniquedGraph &G);
/// Remap a node's operands using the given functor.
///
/// Iterate through the operands of \c N and update them in place using \c
/// mapOperand.
///
/// \pre N.isDistinct() or N.isTemporary().
template <class OperandMapper>
void remapOperands(MDNode &N, OperandMapper mapOperand);
};
} // end namespace
Value *Mapper::mapValue(const Value *V) {
ValueToValueMapTy::iterator I = getVM().find(V);
// If the value already exists in the map, use it.
if (I != getVM().end()) {
assert(I->second && "Unexpected null mapping");
return I->second;
}
// If we have a materializer and it can materialize a value, use that.
if (auto *Materializer = getMaterializer()) {
if (Value *NewV = Materializer->materialize(const_cast<Value *>(V))) {
getVM()[V] = NewV;
return NewV;
}
}
// Global values do not need to be seeded into the VM if they
// are using the identity mapping.
if (isa<GlobalValue>(V)) {
if (Flags & RF_NullMapMissingGlobalValues)
return nullptr;
return getVM()[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 getVM()[V] = const_cast<Value *>(V);
}
if (const auto *MDV = dyn_cast<MetadataAsValue>(V)) {
const Metadata *MD = MDV->getMetadata();
if (auto *LAM = dyn_cast<LocalAsMetadata>(MD)) {
// Look through to grab the local value.
if (Value *LV = mapValue(LAM->getValue())) {
if (V == LAM->getValue())
return const_cast<Value *>(V);
return MetadataAsValue::get(V->getContext(), ValueAsMetadata::get(LV));
}
// FIXME: always return nullptr once Verifier::verifyDominatesUse()
// ensures metadata operands only reference defined SSA values.
return (Flags & RF_IgnoreMissingLocals)
? nullptr
: MetadataAsValue::get(V->getContext(),
MDTuple::get(V->getContext(), None));
}
// 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 getVM()[V] = const_cast<Value *>(V);
// Map the metadata and turn it into a value.
auto *MappedMD = mapMetadata(MD);
if (MD == MappedMD)
return getVM()[V] = const_cast<Value *>(V);
return getVM()[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))
return mapBlockAddress(*BA);
auto mapValueOrNull = [this](Value *V) {
auto Mapped = mapValue(V);
assert((Mapped || (Flags & RF_NullMapMissingGlobalValues)) &&
"Unexpected null mapping for constant operand without "
"NullMapMissingGlobalValues flag");
return Mapped;
};
// 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 = mapValueOrNull(Op);
if (!Mapped)
return nullptr;
if (Mapped != Op)
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 getVM()[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) {
Mapped = mapValueOrNull(C->getOperand(OpNo));
if (!Mapped)
return nullptr;
Ops.push_back(cast<Constant>(Mapped));
}
}
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 getVM()[V] = CE->getWithOperands(Ops, NewTy, false, NewSrcTy);
if (isa<ConstantArray>(C))
return getVM()[V] = ConstantArray::get(cast<ArrayType>(NewTy), Ops);
if (isa<ConstantStruct>(C))
return getVM()[V] = ConstantStruct::get(cast<StructType>(NewTy), Ops);
if (isa<ConstantVector>(C))
return getVM()[V] = ConstantVector::get(Ops);
// If this is a no-operand constant, it must be because the type was remapped.
if (isa<UndefValue>(C))
return getVM()[V] = UndefValue::get(NewTy);
if (isa<ConstantAggregateZero>(C))
return getVM()[V] = ConstantAggregateZero::get(NewTy);
assert(isa<ConstantPointerNull>(C));
return getVM()[V] = ConstantPointerNull::get(cast<PointerType>(NewTy));
}
Value *Mapper::mapBlockAddress(const BlockAddress &BA) {
Function *F = cast<Function>(mapValue(BA.getFunction()));
// F may not have materialized its initializer. In that case, create a
// dummy basic block for now, and replace it once we've materialized all
// the initializers.
BasicBlock *BB;
if (F->empty()) {
DelayedBBs.push_back(DelayedBasicBlock(BA));
BB = DelayedBBs.back().TempBB.get();
} else {
BB = cast_or_null<BasicBlock>(mapValue(BA.getBasicBlock()));
}
return getVM()[&BA] = BlockAddress::get(F, BB ? BB : BA.getBasicBlock());
}
Metadata *Mapper::mapToMetadata(const Metadata *Key, Metadata *Val) {
getVM().MD()[Key].reset(Val);
return Val;
}
Metadata *Mapper::mapToSelf(const Metadata *MD) {
return mapToMetadata(MD, const_cast<Metadata *>(MD));
}
Optional<Metadata *> MDNodeMapper::tryToMapOperand(const Metadata *Op) {
if (!Op)
return nullptr;
if (Optional<Metadata *> MappedOp = M.mapSimpleMetadata(Op)) {
#ifndef NDEBUG
if (auto *CMD = dyn_cast<ConstantAsMetadata>(Op))
assert((!*MappedOp || M.getVM().count(CMD->getValue()) ||
M.getVM().getMappedMD(Op)) &&
"Expected Value to be memoized");
else
assert((isa<MDString>(Op) || M.getVM().getMappedMD(Op)) &&
"Expected result to be memoized");
#endif
return *MappedOp;
}
const MDNode &N = *cast<MDNode>(Op);
if (N.isDistinct())
return mapDistinctNode(N);
return None;
}
MDNode *MDNodeMapper::mapDistinctNode(const MDNode &N) {
assert(N.isDistinct() && "Expected a distinct node");
assert(!M.getVM().getMappedMD(&N) && "Expected an unmapped node");
DistinctWorklist.push_back(cast<MDNode>(
(M.Flags & RF_MoveDistinctMDs)
? M.mapToSelf(&N)
: M.mapToMetadata(&N, MDNode::replaceWithDistinct(N.clone()))));
return DistinctWorklist.back();
}
static ConstantAsMetadata *wrapConstantAsMetadata(const ConstantAsMetadata &CMD,
Value *MappedV) {
if (CMD.getValue() == MappedV)
return const_cast<ConstantAsMetadata *>(&CMD);
return MappedV ? ConstantAsMetadata::getConstant(MappedV) : nullptr;
}
Optional<Metadata *> MDNodeMapper::getMappedOp(const Metadata *Op) const {
if (!Op)
return nullptr;
if (Optional<Metadata *> MappedOp = M.getVM().getMappedMD(Op))
return *MappedOp;
if (isa<MDString>(Op))
return const_cast<Metadata *>(Op);
if (auto *CMD = dyn_cast<ConstantAsMetadata>(Op))
return wrapConstantAsMetadata(*CMD, M.getVM().lookup(CMD->getValue()));
return None;
}
Metadata &MDNodeMapper::UniquedGraph::getFwdReference(MDNode &Op) {
auto Where = Info.find(&Op);
assert(Where != Info.end() && "Expected a valid reference");
auto &OpD = Where->second;
if (!OpD.HasChanged)
return Op;
// Lazily construct a temporary node.
if (!OpD.Placeholder)
OpD.Placeholder = Op.clone();
return *OpD.Placeholder;
}
template <class OperandMapper>
void MDNodeMapper::remapOperands(MDNode &N, OperandMapper mapOperand) {
assert(!N.isUniqued() && "Expected distinct or temporary nodes");
for (unsigned I = 0, E = N.getNumOperands(); I != E; ++I) {
Metadata *Old = N.getOperand(I);
Metadata *New = mapOperand(Old);
if (Old != New)
N.replaceOperandWith(I, New);
}
}
namespace {
/// An entry in the worklist for the post-order traversal.
struct POTWorklistEntry {
MDNode *N; ///< Current node.
MDNode::op_iterator Op; ///< Current operand of \c N.
/// Keep a flag of whether operands have changed in the worklist to avoid
/// hitting the map in \a UniquedGraph.
bool HasChanged = false;
POTWorklistEntry(MDNode &N) : N(&N), Op(N.op_begin()) {}
};
} // end namespace
bool MDNodeMapper::createPOT(UniquedGraph &G, const MDNode &FirstN) {
assert(G.Info.empty() && "Expected a fresh traversal");
assert(FirstN.isUniqued() && "Expected uniqued node in POT");
// Construct a post-order traversal of the uniqued subgraph under FirstN.
bool AnyChanges = false;
SmallVector<POTWorklistEntry, 16> Worklist;
Worklist.push_back(POTWorklistEntry(const_cast<MDNode &>(FirstN)));
(void)G.Info[&FirstN];
while (!Worklist.empty()) {
// Start or continue the traversal through the this node's operands.
auto &WE = Worklist.back();
if (MDNode *N = visitOperands(G, WE.Op, WE.N->op_end(), WE.HasChanged)) {
// Push a new node to traverse first.
Worklist.push_back(POTWorklistEntry(*N));
continue;
}
// Push the node onto the POT.
assert(WE.N->isUniqued() && "Expected only uniqued nodes");
assert(WE.Op == WE.N->op_end() && "Expected to visit all operands");
auto &D = G.Info[WE.N];
AnyChanges |= D.HasChanged = WE.HasChanged;
D.ID = G.POT.size();
G.POT.push_back(WE.N);
// Pop the node off the worklist.
Worklist.pop_back();
}
return AnyChanges;
}
MDNode *MDNodeMapper::visitOperands(UniquedGraph &G, MDNode::op_iterator &I,
MDNode::op_iterator E, bool &HasChanged) {
while (I != E) {
Metadata *Op = *I++; // Increment even on early return.
if (Optional<Metadata *> MappedOp = tryToMapOperand(Op)) {
// Check if the operand changes.
HasChanged |= Op != *MappedOp;
continue;
}
// A uniqued metadata node.
MDNode &OpN = *cast<MDNode>(Op);
assert(OpN.isUniqued() &&
"Only uniqued operands cannot be mapped immediately");
if (G.Info.insert(std::make_pair(&OpN, Data())).second)
return &OpN; // This is a new one. Return it.
}
return nullptr;
}
void MDNodeMapper::UniquedGraph::propagateChanges() {
bool AnyChanges;
do {
AnyChanges = false;
for (MDNode *N : POT) {
auto &D = Info[N];
if (D.HasChanged)
continue;
if (none_of(N->operands(), [&](const Metadata *Op) {
auto Where = Info.find(Op);
return Where != Info.end() && Where->second.HasChanged;
}))
continue;
AnyChanges = D.HasChanged = true;
}
} while (AnyChanges);
}
void MDNodeMapper::mapNodesInPOT(UniquedGraph &G) {
// Construct uniqued nodes, building forward references as necessary.
SmallVector<MDNode *, 16> CyclicNodes;
for (auto *N : G.POT) {
auto &D = G.Info[N];
if (!D.HasChanged) {
// The node hasn't changed.
M.mapToSelf(N);
continue;
}
// Remember whether this node had a placeholder.
bool HadPlaceholder(D.Placeholder);
// Clone the uniqued node and remap the operands.
TempMDNode ClonedN = D.Placeholder ? std::move(D.Placeholder) : N->clone();
remapOperands(*ClonedN, [this, &D, &G](Metadata *Old) {
if (Optional<Metadata *> MappedOp = getMappedOp(Old))
return *MappedOp;
(void)D;
assert(G.Info[Old].ID > D.ID && "Expected a forward reference");
return &G.getFwdReference(*cast<MDNode>(Old));
});
auto *NewN = MDNode::replaceWithUniqued(std::move(ClonedN));
M.mapToMetadata(N, NewN);
// Nodes that were referenced out of order in the POT are involved in a
// uniquing cycle.
if (HadPlaceholder)
CyclicNodes.push_back(NewN);
}
// Resolve cycles.
for (auto *N : CyclicNodes)
if (!N->isResolved())
N->resolveCycles();
}
Metadata *MDNodeMapper::map(const MDNode &N) {
assert(DistinctWorklist.empty() && "MDNodeMapper::map is not recursive");
assert(!(M.Flags & RF_NoModuleLevelChanges) &&
"MDNodeMapper::map assumes module-level changes");
// Require resolved nodes whenever metadata might be remapped.
assert(N.isResolved() && "Unexpected unresolved node");
Metadata *MappedN =
N.isUniqued() ? mapTopLevelUniquedNode(N) : mapDistinctNode(N);
while (!DistinctWorklist.empty())
remapOperands(*DistinctWorklist.pop_back_val(), [this](Metadata *Old) {
if (Optional<Metadata *> MappedOp = tryToMapOperand(Old))
return *MappedOp;
return mapTopLevelUniquedNode(*cast<MDNode>(Old));
});
return MappedN;
}
Metadata *MDNodeMapper::mapTopLevelUniquedNode(const MDNode &FirstN) {
assert(FirstN.isUniqued() && "Expected uniqued node");
// Create a post-order traversal of uniqued nodes under FirstN.
UniquedGraph G;
if (!createPOT(G, FirstN)) {
// Return early if no nodes have changed.
for (const MDNode *N : G.POT)
M.mapToSelf(N);
return &const_cast<MDNode &>(FirstN);
}
// Update graph with all nodes that have changed.
G.propagateChanges();
// Map all the nodes in the graph.
mapNodesInPOT(G);
// Return the original node, remapped.
return *getMappedOp(&FirstN);
}
namespace {
struct MapMetadataDisabler {
ValueToValueMapTy &VM;
MapMetadataDisabler(ValueToValueMapTy &VM) : VM(VM) {
VM.disableMapMetadata();
}
~MapMetadataDisabler() { VM.enableMapMetadata(); }
};
} // end namespace
Optional<Metadata *> Mapper::mapSimpleMetadata(const Metadata *MD) {
// If the value already exists in the map, use it.
if (Optional<Metadata *> NewMD = getVM().getMappedMD(MD))
return *NewMD;
if (isa<MDString>(MD))
return const_cast<Metadata *>(MD);
// This is a module-level metadata. If nothing at the module level is
// changing, use an identity mapping.
if ((Flags & RF_NoModuleLevelChanges))
return const_cast<Metadata *>(MD);
if (auto *CMD = dyn_cast<ConstantAsMetadata>(MD)) {
// Disallow recursion into metadata mapping through mapValue.
MapMetadataDisabler MMD(getVM());
// Don't memoize ConstantAsMetadata. Instead of lasting until the
// LLVMContext is destroyed, they can be deleted when the GlobalValue they
// reference is destructed. These aren't super common, so the extra
// indirection isn't that expensive.
return wrapConstantAsMetadata(*CMD, mapValue(CMD->getValue()));
}
assert(isa<MDNode>(MD) && "Expected a metadata node");
return None;
}
Metadata *Mapper::mapMetadata(const Metadata *MD) {
assert(MD && "Expected valid metadata");
assert(!isa<LocalAsMetadata>(MD) && "Unexpected local metadata");
if (Optional<Metadata *> NewMD = mapSimpleMetadata(MD))
return *NewMD;
return MDNodeMapper(*this).map(*cast<MDNode>(MD));
}
void Mapper::flush() {
// Flush out the worklist of global values.
while (!Worklist.empty()) {
WorklistEntry E = Worklist.pop_back_val();
CurrentMCID = E.MCID;
switch (E.Kind) {
case WorklistEntry::MapGlobalInit:
E.Data.GVInit.GV->setInitializer(mapConstant(E.Data.GVInit.Init));
break;
case WorklistEntry::MapAppendingVar: {
unsigned PrefixSize = AppendingInits.size() - E.AppendingGVNumNewMembers;
mapAppendingVariable(*E.Data.AppendingGV.GV,
E.Data.AppendingGV.InitPrefix,
E.AppendingGVIsOldCtorDtor,
makeArrayRef(AppendingInits).slice(PrefixSize));
AppendingInits.resize(PrefixSize);
break;
}
case WorklistEntry::MapGlobalAliasee:
E.Data.GlobalAliasee.GA->setAliasee(
mapConstant(E.Data.GlobalAliasee.Aliasee));
break;
case WorklistEntry::RemapFunction:
remapFunction(*E.Data.RemapF);
break;
}
}
CurrentMCID = 0;
// Finish logic for block addresses now that all global values have been
// handled.
while (!DelayedBBs.empty()) {
DelayedBasicBlock DBB = DelayedBBs.pop_back_val();
BasicBlock *BB = cast_or_null<BasicBlock>(mapValue(DBB.OldBB));
DBB.TempBB->replaceAllUsesWith(BB ? BB : DBB.OldBB);
}
}
void Mapper::remapInstruction(Instruction *I) {
// Remap operands.
for (Use &Op : I->operands()) {
Value *V = mapValue(Op);
// If we aren't ignoring missing entries, assert that something happened.
if (V)
Op = V;
else
assert((Flags & RF_IgnoreMissingLocals) &&
"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));
// If we aren't ignoring missing entries, assert that something happened.
if (V)
PN->setIncomingBlock(i, cast<BasicBlock>(V));
else
assert((Flags & RF_IgnoreMissingLocals) &&
"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 = cast_or_null<MDNode>(mapMetadata(Old));
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()));
}
void Mapper::remapFunction(Function &F) {
// Remap the operands.
for (Use &Op : F.operands())
if (Op)
Op = mapValue(Op);
// Remap the metadata attachments.
SmallVector<std::pair<unsigned, MDNode *>, 8> MDs;
F.getAllMetadata(MDs);
F.clearMetadata();
for (const auto &I : MDs)
F.addMetadata(I.first, *cast<MDNode>(mapMetadata(I.second)));
// Remap the argument types.
if (TypeMapper)
for (Argument &A : F.args())
A.mutateType(TypeMapper->remapType(A.getType()));
// Remap the instructions.
for (BasicBlock &BB : F)
for (Instruction &I : BB)
remapInstruction(&I);
}
void Mapper::mapAppendingVariable(GlobalVariable &GV, Constant *InitPrefix,
bool IsOldCtorDtor,
ArrayRef<Constant *> NewMembers) {
SmallVector<Constant *, 16> Elements;
if (InitPrefix) {
unsigned NumElements =
cast<ArrayType>(InitPrefix->getType())->getNumElements();
for (unsigned I = 0; I != NumElements; ++I)
Elements.push_back(InitPrefix->getAggregateElement(I));
}
PointerType *VoidPtrTy;
Type *EltTy;
if (IsOldCtorDtor) {
// FIXME: This upgrade is done during linking to support the C API. See
// also IRLinker::linkAppendingVarProto() in IRMover.cpp.
VoidPtrTy = Type::getInt8Ty(GV.getContext())->getPointerTo();
auto &ST = *cast<StructType>(NewMembers.front()->getType());
Type *Tys[3] = {ST.getElementType(0), ST.getElementType(1), VoidPtrTy};
EltTy = StructType::get(GV.getContext(), Tys, false);
}
for (auto *V : NewMembers) {
Constant *NewV;
if (IsOldCtorDtor) {
auto *S = cast<ConstantStruct>(V);
auto *E1 = mapValue(S->getOperand(0));
auto *E2 = mapValue(S->getOperand(1));
Value *Null = Constant::getNullValue(VoidPtrTy);
NewV =
ConstantStruct::get(cast<StructType>(EltTy), E1, E2, Null, nullptr);
} else {
NewV = cast_or_null<Constant>(mapValue(V));
}
Elements.push_back(NewV);
}
GV.setInitializer(ConstantArray::get(
cast<ArrayType>(GV.getType()->getElementType()), Elements));
}
void Mapper::scheduleMapGlobalInitializer(GlobalVariable &GV, Constant &Init,
unsigned MCID) {
assert(AlreadyScheduled.insert(&GV).second && "Should not reschedule");
assert(MCID < MCs.size() && "Invalid mapping context");
WorklistEntry WE;
WE.Kind = WorklistEntry::MapGlobalInit;
WE.MCID = MCID;
WE.Data.GVInit.GV = &GV;
WE.Data.GVInit.Init = &Init;
Worklist.push_back(WE);
}
void Mapper::scheduleMapAppendingVariable(GlobalVariable &GV,
Constant *InitPrefix,
bool IsOldCtorDtor,
ArrayRef<Constant *> NewMembers,
unsigned MCID) {
assert(AlreadyScheduled.insert(&GV).second && "Should not reschedule");
assert(MCID < MCs.size() && "Invalid mapping context");
WorklistEntry WE;
WE.Kind = WorklistEntry::MapAppendingVar;
WE.MCID = MCID;
WE.Data.AppendingGV.GV = &GV;
WE.Data.AppendingGV.InitPrefix = InitPrefix;
WE.AppendingGVIsOldCtorDtor = IsOldCtorDtor;
WE.AppendingGVNumNewMembers = NewMembers.size();
Worklist.push_back(WE);
AppendingInits.append(NewMembers.begin(), NewMembers.end());
}
void Mapper::scheduleMapGlobalAliasee(GlobalAlias &GA, Constant &Aliasee,
unsigned MCID) {
assert(AlreadyScheduled.insert(&GA).second && "Should not reschedule");
assert(MCID < MCs.size() && "Invalid mapping context");
WorklistEntry WE;
WE.Kind = WorklistEntry::MapGlobalAliasee;
WE.MCID = MCID;
WE.Data.GlobalAliasee.GA = &GA;
WE.Data.GlobalAliasee.Aliasee = &Aliasee;
Worklist.push_back(WE);
}
void Mapper::scheduleRemapFunction(Function &F, unsigned MCID) {
assert(AlreadyScheduled.insert(&F).second && "Should not reschedule");
assert(MCID < MCs.size() && "Invalid mapping context");
WorklistEntry WE;
WE.Kind = WorklistEntry::RemapFunction;
WE.MCID = MCID;
WE.Data.RemapF = &F;
Worklist.push_back(WE);
}
void Mapper::addFlags(RemapFlags Flags) {
assert(!hasWorkToDo() && "Expected to have flushed the worklist");
this->Flags = this->Flags | Flags;
}
static Mapper *getAsMapper(void *pImpl) {
return reinterpret_cast<Mapper *>(pImpl);
}
namespace {
class FlushingMapper {
Mapper &M;
public:
explicit FlushingMapper(void *pImpl) : M(*getAsMapper(pImpl)) {
assert(!M.hasWorkToDo() && "Expected to be flushed");
}
~FlushingMapper() { M.flush(); }
Mapper *operator->() const { return &M; }
};
} // end namespace
ValueMapper::ValueMapper(ValueToValueMapTy &VM, RemapFlags Flags,
ValueMapTypeRemapper *TypeMapper,
ValueMaterializer *Materializer)
: pImpl(new Mapper(VM, Flags, TypeMapper, Materializer)) {}
ValueMapper::~ValueMapper() { delete getAsMapper(pImpl); }
unsigned
ValueMapper::registerAlternateMappingContext(ValueToValueMapTy &VM,
ValueMaterializer *Materializer) {
return getAsMapper(pImpl)->registerAlternateMappingContext(VM, Materializer);
}
void ValueMapper::addFlags(RemapFlags Flags) {
FlushingMapper(pImpl)->addFlags(Flags);
}
Value *ValueMapper::mapValue(const Value &V) {
return FlushingMapper(pImpl)->mapValue(&V);
}
Constant *ValueMapper::mapConstant(const Constant &C) {
return cast_or_null<Constant>(mapValue(C));
}
Metadata *ValueMapper::mapMetadata(const Metadata &MD) {
return FlushingMapper(pImpl)->mapMetadata(&MD);
}
MDNode *ValueMapper::mapMDNode(const MDNode &N) {
return cast_or_null<MDNode>(mapMetadata(N));
}
void ValueMapper::remapInstruction(Instruction &I) {
FlushingMapper(pImpl)->remapInstruction(&I);
}
void ValueMapper::remapFunction(Function &F) {
FlushingMapper(pImpl)->remapFunction(F);
}
void ValueMapper::scheduleMapGlobalInitializer(GlobalVariable &GV,
Constant &Init,
unsigned MCID) {
getAsMapper(pImpl)->scheduleMapGlobalInitializer(GV, Init, MCID);
}
void ValueMapper::scheduleMapAppendingVariable(GlobalVariable &GV,
Constant *InitPrefix,
bool IsOldCtorDtor,
ArrayRef<Constant *> NewMembers,
unsigned MCID) {
getAsMapper(pImpl)->scheduleMapAppendingVariable(
GV, InitPrefix, IsOldCtorDtor, NewMembers, MCID);
}
void ValueMapper::scheduleMapGlobalAliasee(GlobalAlias &GA, Constant &Aliasee,
unsigned MCID) {
getAsMapper(pImpl)->scheduleMapGlobalAliasee(GA, Aliasee, MCID);
}
void ValueMapper::scheduleRemapFunction(Function &F, unsigned MCID) {
getAsMapper(pImpl)->scheduleRemapFunction(F, MCID);
}
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