llvm/lib/MC/MCContext.cpp
Benjamin Kramer 47f9a49560 Simplify MCContext::(Next|Get)Instance
- Allocate MCLabels in the context so they don't leak.
- Avoid duplicated densemap lookup.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104020 91177308-0d34-0410-b5e6-96231b3b80d8
2010-05-18 12:15:34 +00:00

177 lines
6.2 KiB
C++

//===- lib/MC/MCContext.cpp - Machine Code Context ------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCLabel.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
using namespace llvm;
typedef StringMap<const MCSectionMachO*> MachOUniqueMapTy;
typedef StringMap<const MCSectionELF*> ELFUniqueMapTy;
typedef StringMap<const MCSectionCOFF*> COFFUniqueMapTy;
MCContext::MCContext(const MCAsmInfo &mai) : MAI(mai), NextUniqueID(0) {
MachOUniquingMap = 0;
ELFUniquingMap = 0;
COFFUniquingMap = 0;
}
MCContext::~MCContext() {
// NOTE: The symbols are all allocated out of a bump pointer allocator,
// we don't need to free them here.
// If we have the MachO uniquing map, free it.
delete (MachOUniqueMapTy*)MachOUniquingMap;
delete (ELFUniqueMapTy*)ELFUniquingMap;
delete (COFFUniqueMapTy*)COFFUniquingMap;
}
//===----------------------------------------------------------------------===//
// Symbol Manipulation
//===----------------------------------------------------------------------===//
MCSymbol *MCContext::GetOrCreateSymbol(StringRef Name) {
assert(!Name.empty() && "Normal symbols cannot be unnamed!");
// Determine whether this is an assembler temporary or normal label.
bool isTemporary = Name.startswith(MAI.getPrivateGlobalPrefix());
// Do the lookup and get the entire StringMapEntry. We want access to the
// key if we are creating the entry.
StringMapEntry<MCSymbol*> &Entry = Symbols.GetOrCreateValue(Name);
if (Entry.getValue()) return Entry.getValue();
// Ok, the entry doesn't already exist. Have the MCSymbol object itself refer
// to the copy of the string that is embedded in the StringMapEntry.
MCSymbol *Result = new (*this) MCSymbol(Entry.getKey(), isTemporary);
Entry.setValue(Result);
return Result;
}
MCSymbol *MCContext::GetOrCreateSymbol(const Twine &Name) {
SmallString<128> NameSV;
Name.toVector(NameSV);
return GetOrCreateSymbol(NameSV.str());
}
MCSymbol *MCContext::CreateTempSymbol() {
return GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix()) +
"tmp" + Twine(NextUniqueID++));
}
unsigned MCContext::NextInstance(int64_t LocalLabelVal) {
MCLabel *&Label = Instances[LocalLabelVal];
if (!Label)
Label = new (*this) MCLabel(0);
return Label->incInstance();
}
unsigned MCContext::GetInstance(int64_t LocalLabelVal) {
MCLabel *&Label = Instances[LocalLabelVal];
if (!Label)
Label = new (*this) MCLabel(0);
return Label->getInstance();
}
MCSymbol *MCContext::CreateDirectionalLocalSymbol(int64_t LocalLabelVal) {
return GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix()) +
Twine(LocalLabelVal) +
"\2" +
Twine(NextInstance(LocalLabelVal)));
}
MCSymbol *MCContext::GetDirectionalLocalSymbol(int64_t LocalLabelVal,
int bORf) {
return GetOrCreateSymbol(Twine(MAI.getPrivateGlobalPrefix()) +
Twine(LocalLabelVal) +
"\2" +
Twine(GetInstance(LocalLabelVal) + bORf));
}
MCSymbol *MCContext::LookupSymbol(StringRef Name) const {
return Symbols.lookup(Name);
}
//===----------------------------------------------------------------------===//
// Section Management
//===----------------------------------------------------------------------===//
const MCSectionMachO *MCContext::
getMachOSection(StringRef Segment, StringRef Section,
unsigned TypeAndAttributes,
unsigned Reserved2, SectionKind Kind) {
// We unique sections by their segment/section pair. The returned section
// may not have the same flags as the requested section, if so this should be
// diagnosed by the client as an error.
// Create the map if it doesn't already exist.
if (MachOUniquingMap == 0)
MachOUniquingMap = new MachOUniqueMapTy();
MachOUniqueMapTy &Map = *(MachOUniqueMapTy*)MachOUniquingMap;
// Form the name to look up.
SmallString<64> Name;
Name += Segment;
Name.push_back(',');
Name += Section;
// Do the lookup, if we have a hit, return it.
const MCSectionMachO *&Entry = Map[Name.str()];
if (Entry) return Entry;
// Otherwise, return a new section.
return Entry = new (*this) MCSectionMachO(Segment, Section, TypeAndAttributes,
Reserved2, Kind);
}
const MCSection *MCContext::
getELFSection(StringRef Section, unsigned Type, unsigned Flags,
SectionKind Kind, bool IsExplicit) {
if (ELFUniquingMap == 0)
ELFUniquingMap = new ELFUniqueMapTy();
ELFUniqueMapTy &Map = *(ELFUniqueMapTy*)ELFUniquingMap;
// Do the lookup, if we have a hit, return it.
StringMapEntry<const MCSectionELF*> &Entry = Map.GetOrCreateValue(Section);
if (Entry.getValue()) return Entry.getValue();
MCSectionELF *Result = new (*this) MCSectionELF(Entry.getKey(), Type, Flags,
Kind, IsExplicit);
Entry.setValue(Result);
return Result;
}
const MCSection *MCContext::getCOFFSection(StringRef Section,
unsigned Characteristics,
int Selection,
SectionKind Kind) {
if (COFFUniquingMap == 0)
COFFUniquingMap = new COFFUniqueMapTy();
COFFUniqueMapTy &Map = *(COFFUniqueMapTy*)COFFUniquingMap;
// Do the lookup, if we have a hit, return it.
StringMapEntry<const MCSectionCOFF*> &Entry = Map.GetOrCreateValue(Section);
if (Entry.getValue()) return Entry.getValue();
MCSectionCOFF *Result = new (*this) MCSectionCOFF(Entry.getKey(),
Characteristics,
Selection, Kind);
Entry.setValue(Result);
return Result;
}