llvm-6502/lib/MC/MCContext.cpp
Rafael Espindola 9936b80df5 Compute the ELF SectionKind from the flags.
Any code creating an MCSectionELF knows ELF and already provides the flags.

SectionKind is an abstraction used by common code that uses a plain
MCSection.

Use the flags to compute the SectionKind. This removes a lot of
guessing and boilerplate from the MCSectionELF construction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227476 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-29 17:33:21 +00:00

424 lines
14 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/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MCLabel.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/SourceMgr.h"
#include <map>
using namespace llvm;
MCContext::MCContext(const MCAsmInfo *mai, const MCRegisterInfo *mri,
const MCObjectFileInfo *mofi, const SourceMgr *mgr,
bool DoAutoReset)
: SrcMgr(mgr), MAI(mai), MRI(mri), MOFI(mofi), Allocator(),
Symbols(Allocator), UsedNames(Allocator), NextUniqueID(0),
CurrentDwarfLoc(0, 0, 0, DWARF2_FLAG_IS_STMT, 0, 0), DwarfLocSeen(false),
GenDwarfForAssembly(false), GenDwarfFileNumber(0), DwarfVersion(4),
AllowTemporaryLabels(true), DwarfCompileUnitID(0),
AutoReset(DoAutoReset) {
std::error_code EC = llvm::sys::fs::current_path(CompilationDir);
if (EC)
CompilationDir.clear();
SecureLogFile = getenv("AS_SECURE_LOG_FILE");
SecureLog = nullptr;
SecureLogUsed = false;
if (SrcMgr && SrcMgr->getNumBuffers())
MainFileName =
SrcMgr->getMemoryBuffer(SrcMgr->getMainFileID())->getBufferIdentifier();
}
MCContext::~MCContext() {
if (AutoReset)
reset();
// NOTE: The symbols are all allocated out of a bump pointer allocator,
// we don't need to free them here.
// If the stream for the .secure_log_unique directive was created free it.
delete (raw_ostream*)SecureLog;
}
//===----------------------------------------------------------------------===//
// Module Lifetime Management
//===----------------------------------------------------------------------===//
void MCContext::reset() {
UsedNames.clear();
Symbols.clear();
Allocator.Reset();
Instances.clear();
CompilationDir.clear();
MainFileName.clear();
MCDwarfLineTablesCUMap.clear();
SectionStartEndSyms.clear();
MCGenDwarfLabelEntries.clear();
DwarfDebugFlags = StringRef();
DwarfCompileUnitID = 0;
CurrentDwarfLoc = MCDwarfLoc(0,0,0,DWARF2_FLAG_IS_STMT,0,0);
MachOUniquingMap.clear();
ELFUniquingMap.clear();
COFFUniquingMap.clear();
NextUniqueID = 0;
AllowTemporaryLabels = true;
DwarfLocSeen = false;
GenDwarfForAssembly = false;
GenDwarfFileNumber = 0;
}
//===----------------------------------------------------------------------===//
// Symbol Manipulation
//===----------------------------------------------------------------------===//
MCSymbol *MCContext::GetOrCreateSymbol(StringRef Name) {
assert(!Name.empty() && "Normal symbols cannot be unnamed!");
MCSymbol *&Sym = Symbols[Name];
if (!Sym)
Sym = CreateSymbol(Name);
return Sym;
}
MCSymbol *MCContext::getOrCreateSectionSymbol(const MCSectionELF &Section) {
MCSymbol *&Sym = SectionSymbols[&Section];
if (Sym)
return Sym;
StringRef Name = Section.getSectionName();
MCSymbol *&OldSym = Symbols[Name];
if (OldSym && OldSym->isUndefined()) {
Sym = OldSym;
return OldSym;
}
auto NameIter = UsedNames.insert(std::make_pair(Name, true)).first;
Sym = new (*this) MCSymbol(NameIter->getKey(), /*isTemporary*/ false);
if (!OldSym)
OldSym = Sym;
return Sym;
}
MCSymbol *MCContext::getOrCreateFrameAllocSymbol(StringRef FuncName) {
return GetOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
"frameallocation_" + FuncName);
}
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());
auto NameEntry = UsedNames.insert(std::make_pair(Name, true));
if (!NameEntry.second) {
assert(isTemporary && "Cannot rename non-temporary symbols");
SmallString<128> NewName = Name;
do {
NewName.resize(Name.size());
raw_svector_ostream(NewName) << NextUniqueID++;
NameEntry = UsedNames.insert(std::make_pair(NewName, true));
} while (!NameEntry.second);
}
// 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.first->getKey(), isTemporary);
return Result;
}
MCSymbol *MCContext::GetOrCreateSymbol(const Twine &Name) {
SmallString<128> NameSV;
return GetOrCreateSymbol(Name.toStringRef(NameSV));
}
MCSymbol *MCContext::CreateLinkerPrivateTempSymbol() {
SmallString<128> NameSV;
raw_svector_ostream(NameSV)
<< MAI->getLinkerPrivateGlobalPrefix() << "tmp" << NextUniqueID++;
return CreateSymbol(NameSV);
}
MCSymbol *MCContext::CreateTempSymbol() {
SmallString<128> NameSV;
raw_svector_ostream(NameSV)
<< MAI->getPrivateGlobalPrefix() << "tmp" << NextUniqueID++;
return CreateSymbol(NameSV);
}
unsigned MCContext::NextInstance(unsigned LocalLabelVal) {
MCLabel *&Label = Instances[LocalLabelVal];
if (!Label)
Label = new (*this) MCLabel(0);
return Label->incInstance();
}
unsigned MCContext::GetInstance(unsigned LocalLabelVal) {
MCLabel *&Label = Instances[LocalLabelVal];
if (!Label)
Label = new (*this) MCLabel(0);
return Label->getInstance();
}
MCSymbol *MCContext::getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
unsigned Instance) {
MCSymbol *&Sym = LocalSymbols[std::make_pair(LocalLabelVal, Instance)];
if (!Sym)
Sym = CreateTempSymbol();
return Sym;
}
MCSymbol *MCContext::CreateDirectionalLocalSymbol(unsigned LocalLabelVal) {
unsigned Instance = NextInstance(LocalLabelVal);
return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
}
MCSymbol *MCContext::GetDirectionalLocalSymbol(unsigned LocalLabelVal,
bool Before) {
unsigned Instance = GetInstance(LocalLabelVal);
if (!Before)
++Instance;
return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
}
MCSymbol *MCContext::LookupSymbol(StringRef Name) const {
return Symbols.lookup(Name);
}
MCSymbol *MCContext::LookupSymbol(const Twine &Name) const {
SmallString<128> NameSV;
Name.toVector(NameSV);
return LookupSymbol(NameSV.str());
}
//===----------------------------------------------------------------------===//
// 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.
// 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 = MachOUniquingMap[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) {
return getELFSection(Section, Type, Flags, 0, "");
}
void MCContext::renameELFSection(const MCSectionELF *Section, StringRef Name) {
StringRef GroupName;
if (const MCSymbol *Group = Section->getGroup())
GroupName = Group->getName();
ELFUniquingMap.erase(SectionGroupPair(Section->getSectionName(), GroupName));
auto I =
ELFUniquingMap.insert(std::make_pair(SectionGroupPair(Name, GroupName),
Section)).first;
StringRef CachedName = I->first.first;
const_cast<MCSectionELF*>(Section)->setSectionName(CachedName);
}
const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
unsigned Flags, unsigned EntrySize,
StringRef Group) {
// Do the lookup, if we have a hit, return it.
auto IterBool = ELFUniquingMap.insert(
std::make_pair(SectionGroupPair(Section, Group), nullptr));
auto &Entry = *IterBool.first;
if (!IterBool.second) return Entry.second;
MCSymbol *GroupSym = nullptr;
if (!Group.empty())
GroupSym = GetOrCreateSymbol(Group);
StringRef CachedName = Entry.first.first;
SectionKind Kind;
if (Flags & ELF::SHF_EXECINSTR)
Kind = SectionKind::getText();
else
Kind = SectionKind::getReadOnly();
MCSectionELF *Result = new (*this)
MCSectionELF(CachedName, Type, Flags, Kind, EntrySize, GroupSym);
Entry.second = Result;
return Result;
}
const MCSectionELF *MCContext::CreateELFGroupSection() {
MCSectionELF *Result =
new (*this) MCSectionELF(".group", ELF::SHT_GROUP, 0,
SectionKind::getReadOnly(), 4, nullptr);
return Result;
}
const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
unsigned Characteristics,
SectionKind Kind,
StringRef COMDATSymName,
int Selection) {
// Do the lookup, if we have a hit, return it.
SectionGroupTriple T(Section, COMDATSymName, Selection);
auto IterBool = COFFUniquingMap.insert(std::make_pair(T, nullptr));
auto Iter = IterBool.first;
if (!IterBool.second)
return Iter->second;
MCSymbol *COMDATSymbol = nullptr;
if (!COMDATSymName.empty())
COMDATSymbol = GetOrCreateSymbol(COMDATSymName);
StringRef CachedName = std::get<0>(Iter->first);
MCSectionCOFF *Result = new (*this)
MCSectionCOFF(CachedName, Characteristics, COMDATSymbol, Selection, Kind);
Iter->second = Result;
return Result;
}
const MCSectionCOFF *
MCContext::getCOFFSection(StringRef Section, unsigned Characteristics,
SectionKind Kind) {
return getCOFFSection(Section, Characteristics, Kind, "", 0);
}
const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section) {
SectionGroupTriple T(Section, "", 0);
auto Iter = COFFUniquingMap.find(T);
if (Iter == COFFUniquingMap.end())
return nullptr;
return Iter->second;
}
const MCSectionCOFF *
MCContext::getAssociativeCOFFSection(const MCSectionCOFF *Sec,
const MCSymbol *KeySym) {
// Return the normal section if we don't have to be associative.
if (!KeySym)
return Sec;
// Make an associative section with the same name and kind as the normal
// section.
unsigned Characteristics =
Sec->getCharacteristics() | COFF::IMAGE_SCN_LNK_COMDAT;
return getCOFFSection(Sec->getSectionName(), Characteristics, Sec->getKind(),
KeySym->getName(),
COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE);
}
//===----------------------------------------------------------------------===//
// 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, unsigned CUID) {
MCDwarfLineTable &Table = MCDwarfLineTablesCUMap[CUID];
return Table.getFile(Directory, FileName, FileNumber);
}
/// isValidDwarfFileNumber - takes a dwarf file number and returns true if it
/// currently is assigned and false otherwise.
bool MCContext::isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID) {
const SmallVectorImpl<MCDwarfFile>& MCDwarfFiles = getMCDwarfFiles(CUID);
if(FileNumber == 0 || FileNumber >= MCDwarfFiles.size())
return false;
return !MCDwarfFiles[FileNumber].Name.empty();
}
/// finalizeDwarfSections - Emit end symbols for each non-empty code section.
/// Also remove empty sections from SectionStartEndSyms, to avoid generating
/// useless debug info for them.
void MCContext::finalizeDwarfSections(MCStreamer &MCOS) {
MCContext &context = MCOS.getContext();
auto sec = SectionStartEndSyms.begin();
while (sec != SectionStartEndSyms.end()) {
assert(sec->second.first && "Start symbol must be set by now");
MCOS.SwitchSection(sec->first);
if (MCOS.mayHaveInstructions()) {
MCSymbol *SectionEndSym = context.CreateTempSymbol();
MCOS.EmitLabel(SectionEndSym);
sec->second.second = SectionEndSym;
++sec;
} else {
MapVector<const MCSection *, std::pair<MCSymbol *, MCSymbol *> >::iterator
to_erase = sec;
sec = SectionStartEndSyms.erase(to_erase);
}
}
}
void MCContext::FatalError(SMLoc Loc, const Twine &Msg) const {
// If we have a source manager and a location, use it. Otherwise just
// use the generic report_fatal_error().
if (!SrcMgr || Loc == SMLoc())
report_fatal_error(Msg, false);
// 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.
sys::RunInterruptHandlers();
exit(1);
}