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llvm-mirror/lib/VMCore/LLVMContext.cpp
Chris Lattner 9ab48420db Fix a major source of compile-time slowness at -O0 -g by optimizing
the storage of !dbg metadata kinds in the instruction themselves.
The on-the-side hash table works great for metadata that not-all
instructions get, or for metadata that only exists when optimizing.
But when compile-time is everything, it isn't great.

I'm not super thrilled with the fact that this plops a TrackingVH in
Instruction, because it grows it by 3 words.  I'm investigating 
alternatives, but this should be a step in the right direction in any
case.

llvm-svn: 99957
2010-03-30 23:03:27 +00:00

78 lines
2.3 KiB
C++

//===-- LLVMContext.cpp - Implement LLVMContext -----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements LLVMContext, as a wrapper around the opaque
// class LLVMContextImpl.
//
//===----------------------------------------------------------------------===//
#include "llvm/LLVMContext.h"
#include "llvm/Metadata.h"
#include "llvm/Constants.h"
#include "llvm/Instruction.h"
#include "llvm/Support/ManagedStatic.h"
#include "LLVMContextImpl.h"
using namespace llvm;
static ManagedStatic<LLVMContext> GlobalContext;
LLVMContext& llvm::getGlobalContext() {
return *GlobalContext;
}
LLVMContext::LLVMContext() : pImpl(new LLVMContextImpl(*this)) {
// Create the first metadata kind, which is always 'dbg'.
unsigned DbgID = getMDKindID("dbg");
assert(DbgID == MD_dbg && "dbg kind id drifted"); (void)DbgID;
}
LLVMContext::~LLVMContext() { delete pImpl; }
#ifndef NDEBUG
/// isValidName - Return true if Name is a valid custom metadata handler name.
static bool isValidName(StringRef MDName) {
if (MDName.empty())
return false;
if (!isalpha(MDName[0]))
return false;
for (StringRef::iterator I = MDName.begin() + 1, E = MDName.end(); I != E;
++I) {
if (!isalnum(*I) && *I != '_' && *I != '-' && *I != '.')
return false;
}
return true;
}
#endif
/// getMDKindID - Return a unique non-zero ID for the specified metadata kind.
unsigned LLVMContext::getMDKindID(StringRef Name) const {
assert(isValidName(Name) && "Invalid MDNode name");
unsigned &Entry = pImpl->CustomMDKindNames[Name];
// If this is new, assign it its ID.
if (Entry == 0) Entry = pImpl->CustomMDKindNames.size();
return Entry;
}
/// getHandlerNames - Populate client supplied smallvector using custome
/// metadata name and ID.
void LLVMContext::getMDKindNames(SmallVectorImpl<StringRef> &Names) const {
Names.resize(pImpl->CustomMDKindNames.size()+1);
Names[0] = "";
for (StringMap<unsigned>::const_iterator I = pImpl->CustomMDKindNames.begin(),
E = pImpl->CustomMDKindNames.end(); I != E; ++I)
// MD Handlers are numbered from 1.
Names[I->second] = I->first();
}