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//===- 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/MCObjectFileInfo.h"
#include "llvm/MC/MCRegisterInfo.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/MC/MCDwarf.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/Signals.h"
using namespace llvm;
typedef StringMap<const MCSectionMachO*> MachOUniqueMapTy;
typedef StringMap<const MCSectionELF*> ELFUniqueMapTy;
typedef StringMap<const MCSectionCOFF*> COFFUniqueMapTy;
MCContext::MCContext(const MCAsmInfo &mai, const MCRegisterInfo &mri,
const MCObjectFileInfo *mofi, const SourceMgr *mgr) :
SrcMgr(mgr), MAI(mai), MRI(mri), MOFI(mofi),
Allocator(), Symbols(Allocator), UsedNames(Allocator),
AllowTemporaryLabels(true) {
MachOUniquingMap = 0;
ELFUniquingMap = 0;
COFFUniquingMap = 0;
SecureLogFile = getenv("AS_SECURE_LOG_FILE");
SecureLog = 0;
SecureLogUsed = false;
DwarfLocSeen = false;
GenDwarfForAssembly = false;
GenDwarfFileNumber = 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;
// If the stream for the .secure_log_unique directive was created free it.
delete (raw_ostream*)SecureLog;
// Symbol Manipulation
MCSymbol *MCContext::GetOrCreateSymbol(StringRef Name) {
assert(!Name.empty() && "Normal symbols cannot be unnamed!");
// 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);
MCSymbol *Sym = Entry.getValue();
if (Sym)
return Sym;
Sym = CreateSymbol(Name);
return Sym;
MCSymbol *MCContext::CreateSymbol(StringRef Name) {
// Determine whether this is an assembler temporary or normal label, if used.
bool isTemporary = false;
if (AllowTemporaryLabels)
isTemporary = Name.startswith(MAI.getPrivateGlobalPrefix());
StringMapEntry<bool> *NameEntry = &UsedNames.GetOrCreateValue(Name);
if (NameEntry->getValue()) {
assert(isTemporary && "Cannot rename non temporary symbols");
SmallString<128> NewName = Name;
do {
raw_svector_ostream(NewName) << NextUniqueID++;
NameEntry = &UsedNames.GetOrCreateValue(NewName);
} while (NameEntry->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 UsedNames entry.
MCSymbol *Result = new (*this) MCSymbol(NameEntry->getKey(), isTemporary);
return Result;
MCSymbol *MCContext::GetOrCreateSymbol(const Twine &Name) {
SmallString<128> NameSV;
return GetOrCreateSymbol(NameSV.str());
MCSymbol *MCContext::CreateTempSymbol() {
SmallString<128> NameSV;
<< MAI.getPrivateGlobalPrefix() << "tmp" << NextUniqueID++;
return CreateSymbol(NameSV);
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" +
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 += 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 MCSectionELF *MCContext::
getELFSection(StringRef Section, unsigned Type, unsigned Flags,
SectionKind Kind) {
return getELFSection(Section, Type, Flags, Kind, 0, "");
const MCSectionELF *MCContext::
getELFSection(StringRef Section, unsigned Type, unsigned Flags,
SectionKind Kind, unsigned EntrySize, StringRef Group) {
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();
// Possibly refine the entry size first.
if (!EntrySize) {
EntrySize = MCSectionELF::DetermineEntrySize(Kind);
MCSymbol *GroupSym = NULL;
if (!Group.empty())
GroupSym = GetOrCreateSymbol(Group);
MCSectionELF *Result = new (*this) MCSectionELF(Entry.getKey(), Type, Flags,
Kind, EntrySize, GroupSym);
return Result;
const MCSectionELF *MCContext::CreateELFGroupSection() {
MCSectionELF *Result =
new (*this) MCSectionELF(".group", ELF::SHT_GROUP, 0,
SectionKind::getReadOnly(), 4, NULL);
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(),
Selection, Kind);
return Result;
// Dwarf Management
/// GetDwarfFile - takes a file name an number to place in the dwarf file and
/// directory tables. If the file number has already been allocated it is an
/// error and zero is returned and the client reports the error, else the
/// allocated file number is returned. The file numbers may be in any order.
unsigned MCContext::GetDwarfFile(StringRef Directory, StringRef FileName,
unsigned FileNumber) {
// TODO: a FileNumber of zero says to use the next available file number.
// Note: in GenericAsmParser::ParseDirectiveFile() FileNumber was checked
// to not be less than one. This needs to be change to be not less than zero.
// Make space for this FileNumber in the MCDwarfFiles vector if needed.
if (FileNumber >= MCDwarfFiles.size()) {
MCDwarfFiles.resize(FileNumber + 1);
} else {
MCDwarfFile *&ExistingFile = MCDwarfFiles[FileNumber];
if (ExistingFile)
// It is an error to use see the same number more than once.
return 0;
// Get the new MCDwarfFile slot for this FileNumber.
MCDwarfFile *&File = MCDwarfFiles[FileNumber];
if (Directory.empty()) {
// Separate the directory part from the basename of the FileName.
std::pair<StringRef, StringRef> Slash = FileName.rsplit('/');
Directory = Slash.second;
if (!Directory.empty()) {
Directory = Slash.first;
FileName = Slash.second;
// Find or make a entry in the MCDwarfDirs vector for this Directory.
// Capture directory name.
unsigned DirIndex;
if (Directory.empty()) {
// For FileNames with no directories a DirIndex of 0 is used.
DirIndex = 0;
} else {
DirIndex = 0;
for (unsigned End = MCDwarfDirs.size(); DirIndex < End; DirIndex++) {
if (Directory == MCDwarfDirs[DirIndex])
if (DirIndex >= MCDwarfDirs.size()) {
char *Buf = static_cast<char *>(Allocate(Directory.size()));
memcpy(Buf,, Directory.size());
MCDwarfDirs.push_back(StringRef(Buf, Directory.size()));
// The DirIndex is one based, as DirIndex of 0 is used for FileNames with
// no directories. MCDwarfDirs[] is unlike MCDwarfFiles[] in that the
// directory names are stored at MCDwarfDirs[DirIndex-1] where FileNames
// are stored at MCDwarfFiles[FileNumber].Name .
// Now make the MCDwarfFile entry and place it in the slot in the MCDwarfFiles
// vector.
char *Buf = static_cast<char *>(Allocate(FileName.size()));
memcpy(Buf,, FileName.size());
File = new (*this) MCDwarfFile(StringRef(Buf, FileName.size()), DirIndex);
// return the allocated FileNumber.
return FileNumber;
/// isValidDwarfFileNumber - takes a dwarf file number and returns true if it
/// currently is assigned and false otherwise.
bool MCContext::isValidDwarfFileNumber(unsigned FileNumber) {
if(FileNumber == 0 || FileNumber >= MCDwarfFiles.size())
return false;
return MCDwarfFiles[FileNumber] != 0;
void MCContext::FatalError(SMLoc Loc, const Twine &Msg) {
// If we have a source manager and a location, use it. Otherwise just
// use the generic report_fatal_error().
if (!SrcMgr || Loc == SMLoc())
// Use the source manager to print the message.
SrcMgr->PrintMessage(Loc, SourceMgr::DK_Error, Msg);
// If we reached here, we are failing ungracefully. Run the interrupt handlers
// to make sure any special cleanups get done, in particular that we remove
// files registered with RemoveFileOnSignal.