llvm-6502/lib/VMCore/Metadata.cpp
Dan Gohman 56b092e4cd Add comments explaining why it's not necessary to include the
is-function-local flag in metadata uniquing bits.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112528 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-30 21:18:41 +00:00

548 lines
18 KiB
C++

//===-- Metadata.cpp - Implement Metadata classes -------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Metadata classes.
//
//===----------------------------------------------------------------------===//
#include "llvm/Metadata.h"
#include "LLVMContextImpl.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Instruction.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/SmallString.h"
#include "SymbolTableListTraitsImpl.h"
#include "llvm/Support/LeakDetector.h"
#include "llvm/Support/ValueHandle.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
// MDString implementation.
//
MDString::MDString(LLVMContext &C, StringRef S)
: Value(Type::getMetadataTy(C), Value::MDStringVal), Str(S) {}
MDString *MDString::get(LLVMContext &Context, StringRef Str) {
LLVMContextImpl *pImpl = Context.pImpl;
StringMapEntry<MDString *> &Entry =
pImpl->MDStringCache.GetOrCreateValue(Str);
MDString *&S = Entry.getValue();
if (!S) S = new MDString(Context, Entry.getKey());
return S;
}
//===----------------------------------------------------------------------===//
// MDNodeOperand implementation.
//
// Use CallbackVH to hold MDNode operands.
namespace llvm {
class MDNodeOperand : public CallbackVH {
MDNode *Parent;
public:
MDNodeOperand(Value *V, MDNode *P) : CallbackVH(V), Parent(P) {}
~MDNodeOperand() {}
void set(Value *V) {
setValPtr(V);
}
virtual void deleted();
virtual void allUsesReplacedWith(Value *NV);
};
} // end namespace llvm.
void MDNodeOperand::deleted() {
Parent->replaceOperand(this, 0);
}
void MDNodeOperand::allUsesReplacedWith(Value *NV) {
Parent->replaceOperand(this, NV);
}
//===----------------------------------------------------------------------===//
// MDNode implementation.
//
/// getOperandPtr - Helper function to get the MDNodeOperand's coallocated on
/// the end of the MDNode.
static MDNodeOperand *getOperandPtr(MDNode *N, unsigned Op) {
// Use <= instead of < to permit a one-past-the-end address.
assert(Op <= N->getNumOperands() && "Invalid operand number");
return reinterpret_cast<MDNodeOperand*>(N+1)+Op;
}
MDNode::MDNode(LLVMContext &C, Value *const *Vals, unsigned NumVals,
bool isFunctionLocal)
: Value(Type::getMetadataTy(C), Value::MDNodeVal) {
NumOperands = NumVals;
if (isFunctionLocal)
setValueSubclassData(getSubclassDataFromValue() | FunctionLocalBit);
// Initialize the operand list, which is co-allocated on the end of the node.
for (MDNodeOperand *Op = getOperandPtr(this, 0), *E = Op+NumOperands;
Op != E; ++Op, ++Vals)
new (Op) MDNodeOperand(*Vals, this);
}
/// ~MDNode - Destroy MDNode.
MDNode::~MDNode() {
assert((getSubclassDataFromValue() & DestroyFlag) != 0 &&
"Not being destroyed through destroy()?");
LLVMContextImpl *pImpl = getType()->getContext().pImpl;
if (isNotUniqued()) {
pImpl->NonUniquedMDNodes.erase(this);
} else {
pImpl->MDNodeSet.RemoveNode(this);
}
// Destroy the operands.
for (MDNodeOperand *Op = getOperandPtr(this, 0), *E = Op+NumOperands;
Op != E; ++Op)
Op->~MDNodeOperand();
}
static const Function *getFunctionForValue(Value *V) {
if (!V) return NULL;
if (Instruction *I = dyn_cast<Instruction>(V)) {
BasicBlock *BB = I->getParent();
return BB ? BB->getParent() : 0;
}
if (Argument *A = dyn_cast<Argument>(V))
return A->getParent();
if (BasicBlock *BB = dyn_cast<BasicBlock>(V))
return BB->getParent();
if (MDNode *MD = dyn_cast<MDNode>(V))
return MD->getFunction();
return NULL;
}
#ifndef NDEBUG
static const Function *assertLocalFunction(const MDNode *N) {
if (!N->isFunctionLocal()) return 0;
// FIXME: This does not handle cyclic function local metadata.
const Function *F = 0, *NewF = 0;
for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
if (Value *V = N->getOperand(i)) {
if (MDNode *MD = dyn_cast<MDNode>(V))
NewF = assertLocalFunction(MD);
else
NewF = getFunctionForValue(V);
}
if (F == 0)
F = NewF;
else
assert((NewF == 0 || F == NewF) &&"inconsistent function-local metadata");
}
return F;
}
#endif
// getFunction - If this metadata is function-local and recursively has a
// function-local operand, return the first such operand's parent function.
// Otherwise, return null. getFunction() should not be used for performance-
// critical code because it recursively visits all the MDNode's operands.
const Function *MDNode::getFunction() const {
#ifndef NDEBUG
return assertLocalFunction(this);
#endif
if (!isFunctionLocal()) return NULL;
for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
if (const Function *F = getFunctionForValue(getOperand(i)))
return F;
return NULL;
}
// destroy - Delete this node. Only when there are no uses.
void MDNode::destroy() {
setValueSubclassData(getSubclassDataFromValue() | DestroyFlag);
// Placement delete, the free the memory.
this->~MDNode();
free(this);
}
/// isFunctionLocalValue - Return true if this is a value that would require a
/// function-local MDNode.
static bool isFunctionLocalValue(Value *V) {
return isa<Instruction>(V) || isa<Argument>(V) || isa<BasicBlock>(V) ||
(isa<MDNode>(V) && cast<MDNode>(V)->isFunctionLocal());
}
MDNode *MDNode::getMDNode(LLVMContext &Context, Value *const *Vals,
unsigned NumVals, FunctionLocalness FL,
bool Insert) {
LLVMContextImpl *pImpl = Context.pImpl;
// Add all the operand pointers. Note that we don't have to add the
// isFunctionLocal bit because that's implied by the operands.
// Note that if the operands are later nulled out, the node will be
// removed from the uniquing map.
FoldingSetNodeID ID;
for (unsigned i = 0; i != NumVals; ++i)
ID.AddPointer(Vals[i]);
void *InsertPoint;
MDNode *N = NULL;
if ((N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint)))
return N;
bool isFunctionLocal = false;
switch (FL) {
case FL_Unknown:
for (unsigned i = 0; i != NumVals; ++i) {
Value *V = Vals[i];
if (!V) continue;
if (isFunctionLocalValue(V)) {
isFunctionLocal = true;
break;
}
}
break;
case FL_No:
isFunctionLocal = false;
break;
case FL_Yes:
isFunctionLocal = true;
break;
}
// Coallocate space for the node and Operands together, then placement new.
void *Ptr = malloc(sizeof(MDNode)+NumVals*sizeof(MDNodeOperand));
N = new (Ptr) MDNode(Context, Vals, NumVals, isFunctionLocal);
// InsertPoint will have been set by the FindNodeOrInsertPos call.
pImpl->MDNodeSet.InsertNode(N, InsertPoint);
return N;
}
MDNode *MDNode::get(LLVMContext &Context, Value*const* Vals, unsigned NumVals) {
return getMDNode(Context, Vals, NumVals, FL_Unknown);
}
MDNode *MDNode::getWhenValsUnresolved(LLVMContext &Context, Value *const *Vals,
unsigned NumVals, bool isFunctionLocal) {
return getMDNode(Context, Vals, NumVals, isFunctionLocal ? FL_Yes : FL_No);
}
MDNode *MDNode::getIfExists(LLVMContext &Context, Value *const *Vals,
unsigned NumVals) {
return getMDNode(Context, Vals, NumVals, FL_Unknown, false);
}
MDNode *MDNode::getTemporary(LLVMContext &Context, Value *const *Vals,
unsigned NumVals) {
MDNode *N = (MDNode *)malloc(sizeof(MDNode)+NumVals*sizeof(MDNodeOperand));
N = new (N) MDNode(Context, Vals, NumVals, FL_No);
N->setValueSubclassData(N->getSubclassDataFromValue() |
NotUniquedBit);
LeakDetector::addGarbageObject(N);
return N;
}
void MDNode::deleteTemporary(MDNode *N) {
assert(N->use_empty() && "Temporary MDNode has uses!");
assert(!N->getContext().pImpl->MDNodeSet.RemoveNode(N) &&
"Deleting a non-temporary uniqued node!");
assert(!N->getContext().pImpl->NonUniquedMDNodes.erase(N) &&
"Deleting a non-temporary non-uniqued node!");
assert((N->getSubclassDataFromValue() & NotUniquedBit) &&
"Temporary MDNode does not have NotUniquedBit set!");
assert((N->getSubclassDataFromValue() & DestroyFlag) == 0 &&
"Temporary MDNode has DestroyFlag set!");
LeakDetector::removeGarbageObject(N);
N->destroy();
}
/// getOperand - Return specified operand.
Value *MDNode::getOperand(unsigned i) const {
return *getOperandPtr(const_cast<MDNode*>(this), i);
}
void MDNode::Profile(FoldingSetNodeID &ID) const {
// Add all the operand pointers. Note that we don't have to add the
// isFunctionLocal bit because that's implied by the operands.
// Note that if the operands are later nulled out, the node will be
// removed from the uniquing map.
for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
ID.AddPointer(getOperand(i));
}
void MDNode::setIsNotUniqued() {
setValueSubclassData(getSubclassDataFromValue() | NotUniquedBit);
LLVMContextImpl *pImpl = getType()->getContext().pImpl;
pImpl->NonUniquedMDNodes.insert(this);
}
// Replace value from this node's operand list.
void MDNode::replaceOperand(MDNodeOperand *Op, Value *To) {
Value *From = *Op;
// If is possible that someone did GV->RAUW(inst), replacing a global variable
// with an instruction or some other function-local object. If this is a
// non-function-local MDNode, it can't point to a function-local object.
// Handle this case by implicitly dropping the MDNode reference to null.
// Likewise if the MDNode is function-local but for a different function.
if (To && isFunctionLocalValue(To)) {
if (!isFunctionLocal())
To = 0;
else {
const Function *F = getFunction();
const Function *FV = getFunctionForValue(To);
// Metadata can be function-local without having an associated function.
// So only consider functions to have changed if non-null.
if (F && FV && F != FV)
To = 0;
}
}
if (From == To)
return;
// Update the operand.
Op->set(To);
// If this node is already not being uniqued (because one of the operands
// already went to null), then there is nothing else to do here.
if (isNotUniqued()) return;
LLVMContextImpl *pImpl = getType()->getContext().pImpl;
// Remove "this" from the context map. FoldingSet doesn't have to reprofile
// this node to remove it, so we don't care what state the operands are in.
pImpl->MDNodeSet.RemoveNode(this);
// If we are dropping an argument to null, we choose to not unique the MDNode
// anymore. This commonly occurs during destruction, and uniquing these
// brings little reuse. Also, this means we don't need to include
// isFunctionLocal bits in FoldingSetNodeIDs for MDNodes.
if (To == 0) {
setIsNotUniqued();
return;
}
// Now that the node is out of the folding set, get ready to reinsert it.
// First, check to see if another node with the same operands already exists
// in the set. If it doesn't exist, this returns the position to insert it.
FoldingSetNodeID ID;
Profile(ID);
void *InsertPoint;
MDNode *N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
if (N) {
N->replaceAllUsesWith(this);
N->destroy();
N = pImpl->MDNodeSet.FindNodeOrInsertPos(ID, InsertPoint);
assert(N == 0 && "shouldn't be in the map now!"); (void)N;
}
// InsertPoint will have been set by the FindNodeOrInsertPos call.
pImpl->MDNodeSet.InsertNode(this, InsertPoint);
}
//===----------------------------------------------------------------------===//
// NamedMDNode implementation.
//
static SmallVector<TrackingVH<MDNode>, 4> &getNMDOps(void *Operands) {
return *(SmallVector<TrackingVH<MDNode>, 4>*)Operands;
}
NamedMDNode::NamedMDNode(const Twine &N)
: Name(N.str()), Parent(0),
Operands(new SmallVector<TrackingVH<MDNode>, 4>()) {
}
NamedMDNode::~NamedMDNode() {
dropAllReferences();
delete &getNMDOps(Operands);
}
/// getNumOperands - Return number of NamedMDNode operands.
unsigned NamedMDNode::getNumOperands() const {
return (unsigned)getNMDOps(Operands).size();
}
/// getOperand - Return specified operand.
MDNode *NamedMDNode::getOperand(unsigned i) const {
assert(i < getNumOperands() && "Invalid Operand number!");
return dyn_cast<MDNode>(&*getNMDOps(Operands)[i]);
}
/// addOperand - Add metadata Operand.
void NamedMDNode::addOperand(MDNode *M) {
getNMDOps(Operands).push_back(TrackingVH<MDNode>(M));
}
/// eraseFromParent - Drop all references and remove the node from parent
/// module.
void NamedMDNode::eraseFromParent() {
getParent()->eraseNamedMetadata(this);
}
/// dropAllReferences - Remove all uses and clear node vector.
void NamedMDNode::dropAllReferences() {
getNMDOps(Operands).clear();
}
/// getName - Return a constant reference to this named metadata's name.
StringRef NamedMDNode::getName() const {
return StringRef(Name);
}
//===----------------------------------------------------------------------===//
// Instruction Metadata method implementations.
//
void Instruction::setMetadata(const char *Kind, MDNode *Node) {
if (Node == 0 && !hasMetadata()) return;
setMetadata(getContext().getMDKindID(Kind), Node);
}
MDNode *Instruction::getMetadataImpl(const char *Kind) const {
return getMetadataImpl(getContext().getMDKindID(Kind));
}
/// setMetadata - Set the metadata of of the specified kind to the specified
/// node. This updates/replaces metadata if already present, or removes it if
/// Node is null.
void Instruction::setMetadata(unsigned KindID, MDNode *Node) {
if (Node == 0 && !hasMetadata()) return;
// Handle 'dbg' as a special case since it is not stored in the hash table.
if (KindID == LLVMContext::MD_dbg) {
DbgLoc = DebugLoc::getFromDILocation(Node);
return;
}
// Handle the case when we're adding/updating metadata on an instruction.
if (Node) {
LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
assert(!Info.empty() == hasMetadataHashEntry() &&
"HasMetadata bit is wonked");
if (Info.empty()) {
setHasMetadataHashEntry(true);
} else {
// Handle replacement of an existing value.
for (unsigned i = 0, e = Info.size(); i != e; ++i)
if (Info[i].first == KindID) {
Info[i].second = Node;
return;
}
}
// No replacement, just add it to the list.
Info.push_back(std::make_pair(KindID, Node));
return;
}
// Otherwise, we're removing metadata from an instruction.
assert(hasMetadataHashEntry() &&
getContext().pImpl->MetadataStore.count(this) &&
"HasMetadata bit out of date!");
LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
// Common case is removing the only entry.
if (Info.size() == 1 && Info[0].first == KindID) {
getContext().pImpl->MetadataStore.erase(this);
setHasMetadataHashEntry(false);
return;
}
// Handle removal of an existing value.
for (unsigned i = 0, e = Info.size(); i != e; ++i)
if (Info[i].first == KindID) {
Info[i] = Info.back();
Info.pop_back();
assert(!Info.empty() && "Removing last entry should be handled above");
return;
}
// Otherwise, removing an entry that doesn't exist on the instruction.
}
MDNode *Instruction::getMetadataImpl(unsigned KindID) const {
// Handle 'dbg' as a special case since it is not stored in the hash table.
if (KindID == LLVMContext::MD_dbg)
return DbgLoc.getAsMDNode(getContext());
if (!hasMetadataHashEntry()) return 0;
LLVMContextImpl::MDMapTy &Info = getContext().pImpl->MetadataStore[this];
assert(!Info.empty() && "bit out of sync with hash table");
for (LLVMContextImpl::MDMapTy::iterator I = Info.begin(), E = Info.end();
I != E; ++I)
if (I->first == KindID)
return I->second;
return 0;
}
void Instruction::getAllMetadataImpl(SmallVectorImpl<std::pair<unsigned,
MDNode*> > &Result) const {
Result.clear();
// Handle 'dbg' as a special case since it is not stored in the hash table.
if (!DbgLoc.isUnknown()) {
Result.push_back(std::make_pair((unsigned)LLVMContext::MD_dbg,
DbgLoc.getAsMDNode(getContext())));
if (!hasMetadataHashEntry()) return;
}
assert(hasMetadataHashEntry() &&
getContext().pImpl->MetadataStore.count(this) &&
"Shouldn't have called this");
const LLVMContextImpl::MDMapTy &Info =
getContext().pImpl->MetadataStore.find(this)->second;
assert(!Info.empty() && "Shouldn't have called this");
Result.append(Info.begin(), Info.end());
// Sort the resulting array so it is stable.
if (Result.size() > 1)
array_pod_sort(Result.begin(), Result.end());
}
void Instruction::
getAllMetadataOtherThanDebugLocImpl(SmallVectorImpl<std::pair<unsigned,
MDNode*> > &Result) const {
Result.clear();
assert(hasMetadataHashEntry() &&
getContext().pImpl->MetadataStore.count(this) &&
"Shouldn't have called this");
const LLVMContextImpl::MDMapTy &Info =
getContext().pImpl->MetadataStore.find(this)->second;
assert(!Info.empty() && "Shouldn't have called this");
Result.append(Info.begin(), Info.end());
// Sort the resulting array so it is stable.
if (Result.size() > 1)
array_pod_sort(Result.begin(), Result.end());
}
/// clearMetadataHashEntries - Clear all hashtable-based metadata from
/// this instruction.
void Instruction::clearMetadataHashEntries() {
assert(hasMetadataHashEntry() && "Caller should check");
getContext().pImpl->MetadataStore.erase(this);
setHasMetadataHashEntry(false);
}