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llvm-mirror/lib/MC/MCContext.cpp
Nikita Popov b6614b2353 Revert [MC][ELF] Emit separate unique sections for different flags 
Commit Message from @MaskRay:

Rust has a fragile embed-bitcode implementation
(bddb59cf07/compiler/rustc_codegen_llvm/src/back/write.rs (L970-L1017))
which relied on the previous LLVM MC behavior.  Rust's LLVM fork
has carried a revert. This commit made the similar revert to help
distributions since they would otherwise probably carry a similar patch
(as they ship rust linked against system LLVM).

Fixes https://bugs.llvm.org/show_bug.cgi?id=51207.

Differential Revision: https://reviews.llvm.org/D107216
2021-09-10 16:55:29 -07:00

991 lines
36 KiB
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//===- lib/MC/MCContext.cpp - Machine Code Context ------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCContext.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/BinaryFormat/XCOFF.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCCodeView.h"
#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCFragment.h"
#include "llvm/MC/MCLabel.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionGOFF.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCSectionWasm.h"
#include "llvm/MC/MCSectionXCOFF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCSymbolCOFF.h"
#include "llvm/MC/MCSymbolELF.h"
#include "llvm/MC/MCSymbolGOFF.h"
#include "llvm/MC/MCSymbolMachO.h"
#include "llvm/MC/MCSymbolWasm.h"
#include "llvm/MC/MCSymbolXCOFF.h"
#include "llvm/MC/SectionKind.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstdlib>
#include <tuple>
#include <utility>
using namespace llvm;
static cl::opt<char*>
AsSecureLogFileName("as-secure-log-file-name",
cl::desc("As secure log file name (initialized from "
"AS_SECURE_LOG_FILE env variable)"),
cl::init(getenv("AS_SECURE_LOG_FILE")), cl::Hidden);
static void defaultDiagHandler(const SMDiagnostic &SMD, bool, const SourceMgr &,
std::vector<const MDNode *> &) {
SMD.print(nullptr, errs());
}
MCContext::MCContext(const Triple &TheTriple, const MCAsmInfo *mai,
const MCRegisterInfo *mri, const MCSubtargetInfo *msti,
const SourceMgr *mgr, MCTargetOptions const *TargetOpts,
bool DoAutoReset)
: TT(TheTriple), SrcMgr(mgr), InlineSrcMgr(nullptr),
DiagHandler(defaultDiagHandler), MAI(mai), MRI(mri), MSTI(msti),
Symbols(Allocator), UsedNames(Allocator),
InlineAsmUsedLabelNames(Allocator),
CurrentDwarfLoc(0, 0, 0, DWARF2_FLAG_IS_STMT, 0, 0),
AutoReset(DoAutoReset), TargetOptions(TargetOpts) {
SecureLogFile = AsSecureLogFileName;
if (SrcMgr && SrcMgr->getNumBuffers())
MainFileName = std::string(SrcMgr->getMemoryBuffer(SrcMgr->getMainFileID())
->getBufferIdentifier());
switch (TheTriple.getObjectFormat()) {
case Triple::MachO:
Env = IsMachO;
break;
case Triple::COFF:
if (!TheTriple.isOSWindows())
report_fatal_error(
"Cannot initialize MC for non-Windows COFF object files.");
Env = IsCOFF;
break;
case Triple::ELF:
Env = IsELF;
break;
case Triple::Wasm:
Env = IsWasm;
break;
case Triple::XCOFF:
Env = IsXCOFF;
break;
case Triple::GOFF:
Env = IsGOFF;
break;
case Triple::UnknownObjectFormat:
report_fatal_error("Cannot initialize MC for unknown object file format.");
break;
}
}
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.
}
void MCContext::initInlineSourceManager() {
if (!InlineSrcMgr)
InlineSrcMgr.reset(new SourceMgr());
}
//===----------------------------------------------------------------------===//
// Module Lifetime Management
//===----------------------------------------------------------------------===//
void MCContext::reset() {
SrcMgr = nullptr;
InlineSrcMgr.reset();
LocInfos.clear();
DiagHandler = defaultDiagHandler;
// Call the destructors so the fragments are freed
COFFAllocator.DestroyAll();
ELFAllocator.DestroyAll();
GOFFAllocator.DestroyAll();
MachOAllocator.DestroyAll();
XCOFFAllocator.DestroyAll();
MCInstAllocator.DestroyAll();
MCSubtargetAllocator.DestroyAll();
InlineAsmUsedLabelNames.clear();
UsedNames.clear();
Symbols.clear();
Allocator.Reset();
Instances.clear();
CompilationDir.clear();
MainFileName.clear();
MCDwarfLineTablesCUMap.clear();
SectionsForRanges.clear();
MCGenDwarfLabelEntries.clear();
DwarfDebugFlags = StringRef();
DwarfCompileUnitID = 0;
CurrentDwarfLoc = MCDwarfLoc(0, 0, 0, DWARF2_FLAG_IS_STMT, 0, 0);
CVContext.reset();
MachOUniquingMap.clear();
ELFUniquingMap.clear();
GOFFUniquingMap.clear();
COFFUniquingMap.clear();
WasmUniquingMap.clear();
XCOFFUniquingMap.clear();
ELFEntrySizeMap.clear();
ELFSeenGenericMergeableSections.clear();
NextID.clear();
AllowTemporaryLabels = true;
DwarfLocSeen = false;
GenDwarfForAssembly = false;
GenDwarfFileNumber = 0;
HadError = false;
}
//===----------------------------------------------------------------------===//
// MCInst Management
//===----------------------------------------------------------------------===//
MCInst *MCContext::createMCInst() {
return new (MCInstAllocator.Allocate()) MCInst;
}
//===----------------------------------------------------------------------===//
// Symbol Manipulation
//===----------------------------------------------------------------------===//
MCSymbol *MCContext::getOrCreateSymbol(const Twine &Name) {
SmallString<128> NameSV;
StringRef NameRef = Name.toStringRef(NameSV);
assert(!NameRef.empty() && "Normal symbols cannot be unnamed!");
MCSymbol *&Sym = Symbols[NameRef];
if (!Sym)
Sym = createSymbol(NameRef, false, false);
return Sym;
}
MCSymbol *MCContext::getOrCreateFrameAllocSymbol(StringRef FuncName,
unsigned Idx) {
return getOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + FuncName +
"$frame_escape_" + Twine(Idx));
}
MCSymbol *MCContext::getOrCreateParentFrameOffsetSymbol(StringRef FuncName) {
return getOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + FuncName +
"$parent_frame_offset");
}
MCSymbol *MCContext::getOrCreateLSDASymbol(StringRef FuncName) {
return getOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + "__ehtable$" +
FuncName);
}
MCSymbol *MCContext::createSymbolImpl(const StringMapEntry<bool> *Name,
bool IsTemporary) {
static_assert(std::is_trivially_destructible<MCSymbolCOFF>(),
"MCSymbol classes must be trivially destructible");
static_assert(std::is_trivially_destructible<MCSymbolELF>(),
"MCSymbol classes must be trivially destructible");
static_assert(std::is_trivially_destructible<MCSymbolMachO>(),
"MCSymbol classes must be trivially destructible");
static_assert(std::is_trivially_destructible<MCSymbolWasm>(),
"MCSymbol classes must be trivially destructible");
static_assert(std::is_trivially_destructible<MCSymbolXCOFF>(),
"MCSymbol classes must be trivially destructible");
switch (getObjectFileType()) {
case MCContext::IsCOFF:
return new (Name, *this) MCSymbolCOFF(Name, IsTemporary);
case MCContext::IsELF:
return new (Name, *this) MCSymbolELF(Name, IsTemporary);
case MCContext::IsGOFF:
return new (Name, *this) MCSymbolGOFF(Name, IsTemporary);
case MCContext::IsMachO:
return new (Name, *this) MCSymbolMachO(Name, IsTemporary);
case MCContext::IsWasm:
return new (Name, *this) MCSymbolWasm(Name, IsTemporary);
case MCContext::IsXCOFF:
return createXCOFFSymbolImpl(Name, IsTemporary);
}
return new (Name, *this) MCSymbol(MCSymbol::SymbolKindUnset, Name,
IsTemporary);
}
MCSymbol *MCContext::createSymbol(StringRef Name, bool AlwaysAddSuffix,
bool CanBeUnnamed) {
if (CanBeUnnamed && !UseNamesOnTempLabels)
return createSymbolImpl(nullptr, true);
// Determine whether this is a user written assembler temporary or normal
// label, if used.
bool IsTemporary = CanBeUnnamed;
if (AllowTemporaryLabels && !IsTemporary)
IsTemporary = Name.startswith(MAI->getPrivateGlobalPrefix());
SmallString<128> NewName = Name;
bool AddSuffix = AlwaysAddSuffix;
unsigned &NextUniqueID = NextID[Name];
while (true) {
if (AddSuffix) {
NewName.resize(Name.size());
raw_svector_ostream(NewName) << NextUniqueID++;
}
auto NameEntry = UsedNames.insert(std::make_pair(NewName.str(), true));
if (NameEntry.second || !NameEntry.first->second) {
// Ok, we found a name.
// Mark it as used for a non-section symbol.
NameEntry.first->second = true;
// Have the MCSymbol object itself refer to the copy of the string that is
// embedded in the UsedNames entry.
return createSymbolImpl(&*NameEntry.first, IsTemporary);
}
assert(IsTemporary && "Cannot rename non-temporary symbols");
AddSuffix = true;
}
llvm_unreachable("Infinite loop");
}
MCSymbol *MCContext::createTempSymbol(const Twine &Name, bool AlwaysAddSuffix) {
SmallString<128> NameSV;
raw_svector_ostream(NameSV) << MAI->getPrivateGlobalPrefix() << Name;
return createSymbol(NameSV, AlwaysAddSuffix, true);
}
MCSymbol *MCContext::createNamedTempSymbol(const Twine &Name) {
SmallString<128> NameSV;
raw_svector_ostream(NameSV) << MAI->getPrivateGlobalPrefix() << Name;
return createSymbol(NameSV, true, false);
}
MCSymbol *MCContext::createLinkerPrivateTempSymbol() {
SmallString<128> NameSV;
raw_svector_ostream(NameSV) << MAI->getLinkerPrivateGlobalPrefix() << "tmp";
return createSymbol(NameSV, true, false);
}
MCSymbol *MCContext::createTempSymbol() { return createTempSymbol("tmp"); }
MCSymbol *MCContext::createNamedTempSymbol() {
return createNamedTempSymbol("tmp");
}
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 = createNamedTempSymbol();
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(const Twine &Name) const {
SmallString<128> NameSV;
StringRef NameRef = Name.toStringRef(NameSV);
return Symbols.lookup(NameRef);
}
void MCContext::setSymbolValue(MCStreamer &Streamer,
StringRef Sym,
uint64_t Val) {
auto Symbol = getOrCreateSymbol(Sym);
Streamer.emitAssignment(Symbol, MCConstantExpr::create(Val, *this));
}
void MCContext::registerInlineAsmLabel(MCSymbol *Sym) {
InlineAsmUsedLabelNames[Sym->getName()] = Sym;
}
MCSymbolXCOFF *
MCContext::createXCOFFSymbolImpl(const StringMapEntry<bool> *Name,
bool IsTemporary) {
if (!Name)
return new (nullptr, *this) MCSymbolXCOFF(nullptr, IsTemporary);
StringRef OriginalName = Name->first();
if (OriginalName.startswith("._Renamed..") ||
OriginalName.startswith("_Renamed.."))
reportError(SMLoc(), "invalid symbol name from source");
if (MAI->isValidUnquotedName(OriginalName))
return new (Name, *this) MCSymbolXCOFF(Name, IsTemporary);
// Now we have a name that contains invalid character(s) for XCOFF symbol.
// Let's replace with something valid, but save the original name so that
// we could still use the original name in the symbol table.
SmallString<128> InvalidName(OriginalName);
// If it's an entry point symbol, we will keep the '.'
// in front for the convention purpose. Otherwise, add "_Renamed.."
// as prefix to signal this is an renamed symbol.
const bool IsEntryPoint = !InvalidName.empty() && InvalidName[0] == '.';
SmallString<128> ValidName =
StringRef(IsEntryPoint ? "._Renamed.." : "_Renamed..");
// Append the hex values of '_' and invalid characters with "_Renamed..";
// at the same time replace invalid characters with '_'.
for (size_t I = 0; I < InvalidName.size(); ++I) {
if (!MAI->isAcceptableChar(InvalidName[I]) || InvalidName[I] == '_') {
raw_svector_ostream(ValidName).write_hex(InvalidName[I]);
InvalidName[I] = '_';
}
}
// Skip entry point symbol's '.' as we already have a '.' in front of
// "_Renamed".
if (IsEntryPoint)
ValidName.append(InvalidName.substr(1, InvalidName.size() - 1));
else
ValidName.append(InvalidName);
auto NameEntry = UsedNames.insert(std::make_pair(ValidName.str(), true));
assert((NameEntry.second || !NameEntry.first->second) &&
"This name is used somewhere else.");
// Mark the name as used for a non-section symbol.
NameEntry.first->second = true;
// Have the MCSymbol object itself refer to the copy of the string
// that is embedded in the UsedNames entry.
MCSymbolXCOFF *XSym = new (&*NameEntry.first, *this)
MCSymbolXCOFF(&*NameEntry.first, IsTemporary);
XSym->setSymbolTableName(MCSymbolXCOFF::getUnqualifiedName(OriginalName));
return XSym;
}
//===----------------------------------------------------------------------===//
// Section Management
//===----------------------------------------------------------------------===//
MCSectionMachO *MCContext::getMachOSection(StringRef Segment, StringRef Section,
unsigned TypeAndAttributes,
unsigned Reserved2, SectionKind Kind,
const char *BeginSymName) {
// 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.
assert(Section.size() <= 16 && "section name is too long");
assert(!memchr(Section.data(), '\0', Section.size()) &&
"section name cannot contain NUL");
// Do the lookup, if we have a hit, return it.
auto R = MachOUniquingMap.try_emplace((Segment + Twine(',') + Section).str());
if (!R.second)
return R.first->second;
MCSymbol *Begin = nullptr;
if (BeginSymName)
Begin = createTempSymbol(BeginSymName, false);
// Otherwise, return a new section.
StringRef Name = R.first->first();
R.first->second = new (MachOAllocator.Allocate())
MCSectionMachO(Segment, Name.substr(Name.size() - Section.size()),
TypeAndAttributes, Reserved2, Kind, Begin);
return R.first->second;
}
void MCContext::renameELFSection(MCSectionELF *Section, StringRef Name) {
StringRef GroupName;
if (const MCSymbol *Group = Section->getGroup())
GroupName = Group->getName();
// This function is only used by .debug*, which should not have the
// SHF_LINK_ORDER flag.
unsigned UniqueID = Section->getUniqueID();
ELFUniquingMap.erase(
ELFSectionKey{Section->getName(), GroupName, "", UniqueID});
auto I = ELFUniquingMap
.insert(std::make_pair(
ELFSectionKey{Name, GroupName, "", UniqueID}, Section))
.first;
StringRef CachedName = I->first.SectionName;
const_cast<MCSectionELF *>(Section)->setSectionName(CachedName);
}
MCSectionELF *MCContext::createELFSectionImpl(StringRef Section, unsigned Type,
unsigned Flags, SectionKind K,
unsigned EntrySize,
const MCSymbolELF *Group,
bool Comdat, unsigned UniqueID,
const MCSymbolELF *LinkedToSym) {
MCSymbolELF *R;
MCSymbol *&Sym = Symbols[Section];
// A section symbol can not redefine regular symbols. There may be multiple
// sections with the same name, in which case the first such section wins.
if (Sym && Sym->isDefined() &&
(!Sym->isInSection() || Sym->getSection().getBeginSymbol() != Sym))
reportError(SMLoc(), "invalid symbol redefinition");
if (Sym && Sym->isUndefined()) {
R = cast<MCSymbolELF>(Sym);
} else {
auto NameIter = UsedNames.insert(std::make_pair(Section, false)).first;
R = new (&*NameIter, *this) MCSymbolELF(&*NameIter, /*isTemporary*/ false);
if (!Sym)
Sym = R;
}
R->setBinding(ELF::STB_LOCAL);
R->setType(ELF::STT_SECTION);
auto *Ret = new (ELFAllocator.Allocate())
MCSectionELF(Section, Type, Flags, K, EntrySize, Group, Comdat, UniqueID,
R, LinkedToSym);
auto *F = new MCDataFragment();
Ret->getFragmentList().insert(Ret->begin(), F);
F->setParent(Ret);
R->setFragment(F);
return Ret;
}
MCSectionELF *MCContext::createELFRelSection(const Twine &Name, unsigned Type,
unsigned Flags, unsigned EntrySize,
const MCSymbolELF *Group,
const MCSectionELF *RelInfoSection) {
StringMap<bool>::iterator I;
bool Inserted;
std::tie(I, Inserted) =
RelSecNames.insert(std::make_pair(Name.str(), true));
return createELFSectionImpl(
I->getKey(), Type, Flags, SectionKind::getReadOnly(), EntrySize, Group,
true, true, cast<MCSymbolELF>(RelInfoSection->getBeginSymbol()));
}
MCSectionELF *MCContext::getELFNamedSection(const Twine &Prefix,
const Twine &Suffix, unsigned Type,
unsigned Flags,
unsigned EntrySize) {
return getELFSection(Prefix + "." + Suffix, Type, Flags, EntrySize, Suffix,
/*IsComdat=*/true);
}
MCSectionELF *MCContext::getELFSection(const Twine &Section, unsigned Type,
unsigned Flags, unsigned EntrySize,
const Twine &Group, bool IsComdat,
unsigned UniqueID,
const MCSymbolELF *LinkedToSym) {
MCSymbolELF *GroupSym = nullptr;
if (!Group.isTriviallyEmpty() && !Group.str().empty())
GroupSym = cast<MCSymbolELF>(getOrCreateSymbol(Group));
return getELFSection(Section, Type, Flags, EntrySize, GroupSym, IsComdat,
UniqueID, LinkedToSym);
}
MCSectionELF *MCContext::getELFSection(const Twine &Section, unsigned Type,
unsigned Flags, unsigned EntrySize,
const MCSymbolELF *GroupSym,
bool IsComdat, unsigned UniqueID,
const MCSymbolELF *LinkedToSym) {
StringRef Group = "";
if (GroupSym)
Group = GroupSym->getName();
assert(!(LinkedToSym && LinkedToSym->getName().empty()));
// Do the lookup, if we have a hit, return it.
auto IterBool = ELFUniquingMap.insert(std::make_pair(
ELFSectionKey{Section.str(), Group,
LinkedToSym ? LinkedToSym->getName() : "", UniqueID},
nullptr));
auto &Entry = *IterBool.first;
if (!IterBool.second)
return Entry.second;
StringRef CachedName = Entry.first.SectionName;
SectionKind Kind;
if (Flags & ELF::SHF_ARM_PURECODE)
Kind = SectionKind::getExecuteOnly();
else if (Flags & ELF::SHF_EXECINSTR)
Kind = SectionKind::getText();
else
Kind = SectionKind::getReadOnly();
MCSectionELF *Result =
createELFSectionImpl(CachedName, Type, Flags, Kind, EntrySize, GroupSym,
IsComdat, UniqueID, LinkedToSym);
Entry.second = Result;
recordELFMergeableSectionInfo(Result->getName(), Result->getFlags(),
Result->getUniqueID(), Result->getEntrySize());
return Result;
}
MCSectionELF *MCContext::createELFGroupSection(const MCSymbolELF *Group,
bool IsComdat) {
return createELFSectionImpl(".group", ELF::SHT_GROUP, 0,
SectionKind::getReadOnly(), 4, Group, IsComdat,
MCSection::NonUniqueID, nullptr);
}
void MCContext::recordELFMergeableSectionInfo(StringRef SectionName,
unsigned Flags, unsigned UniqueID,
unsigned EntrySize) {
bool IsMergeable = Flags & ELF::SHF_MERGE;
if (IsMergeable && (UniqueID == GenericSectionID))
ELFSeenGenericMergeableSections.insert(SectionName);
// For mergeable sections or non-mergeable sections with a generic mergeable
// section name we enter their Unique ID into the ELFEntrySizeMap so that
// compatible globals can be assigned to the same section.
if (IsMergeable || isELFGenericMergeableSection(SectionName)) {
ELFEntrySizeMap.insert(std::make_pair(
ELFEntrySizeKey{SectionName, Flags, EntrySize}, UniqueID));
}
}
bool MCContext::isELFImplicitMergeableSectionNamePrefix(StringRef SectionName) {
return SectionName.startswith(".rodata.str") ||
SectionName.startswith(".rodata.cst");
}
bool MCContext::isELFGenericMergeableSection(StringRef SectionName) {
return isELFImplicitMergeableSectionNamePrefix(SectionName) ||
ELFSeenGenericMergeableSections.count(SectionName);
}
Optional<unsigned> MCContext::getELFUniqueIDForEntsize(StringRef SectionName,
unsigned Flags,
unsigned EntrySize) {
auto I = ELFEntrySizeMap.find(
MCContext::ELFEntrySizeKey{SectionName, Flags, EntrySize});
return (I != ELFEntrySizeMap.end()) ? Optional<unsigned>(I->second) : None;
}
MCSectionGOFF *MCContext::getGOFFSection(StringRef Section, SectionKind Kind) {
// Do the lookup. If we don't have a hit, return a new section.
auto &GOFFSection = GOFFUniquingMap[Section.str()];
if (!GOFFSection)
GOFFSection = new (GOFFAllocator.Allocate()) MCSectionGOFF(Section, Kind);
return GOFFSection;
}
MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
unsigned Characteristics,
SectionKind Kind,
StringRef COMDATSymName, int Selection,
unsigned UniqueID,
const char *BeginSymName) {
MCSymbol *COMDATSymbol = nullptr;
if (!COMDATSymName.empty()) {
COMDATSymbol = getOrCreateSymbol(COMDATSymName);
COMDATSymName = COMDATSymbol->getName();
}
// Do the lookup, if we have a hit, return it.
COFFSectionKey T{Section, COMDATSymName, Selection, UniqueID};
auto IterBool = COFFUniquingMap.insert(std::make_pair(T, nullptr));
auto Iter = IterBool.first;
if (!IterBool.second)
return Iter->second;
MCSymbol *Begin = nullptr;
if (BeginSymName)
Begin = createTempSymbol(BeginSymName, false);
StringRef CachedName = Iter->first.SectionName;
MCSectionCOFF *Result = new (COFFAllocator.Allocate()) MCSectionCOFF(
CachedName, Characteristics, COMDATSymbol, Selection, Kind, Begin);
Iter->second = Result;
return Result;
}
MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
unsigned Characteristics,
SectionKind Kind,
const char *BeginSymName) {
return getCOFFSection(Section, Characteristics, Kind, "", 0, GenericSectionID,
BeginSymName);
}
MCSectionCOFF *MCContext::getAssociativeCOFFSection(MCSectionCOFF *Sec,
const MCSymbol *KeySym,
unsigned UniqueID) {
// Return the normal section if we don't have to be associative or unique.
if (!KeySym && UniqueID == GenericSectionID)
return Sec;
// If we have a key symbol, make an associative section with the same name and
// kind as the normal section.
unsigned Characteristics = Sec->getCharacteristics();
if (KeySym) {
Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
return getCOFFSection(Sec->getName(), Characteristics, Sec->getKind(),
KeySym->getName(),
COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE, UniqueID);
}
return getCOFFSection(Sec->getName(), Characteristics, Sec->getKind(), "", 0,
UniqueID);
}
MCSectionWasm *MCContext::getWasmSection(const Twine &Section, SectionKind K,
unsigned Flags, const Twine &Group,
unsigned UniqueID,
const char *BeginSymName) {
MCSymbolWasm *GroupSym = nullptr;
if (!Group.isTriviallyEmpty() && !Group.str().empty()) {
GroupSym = cast<MCSymbolWasm>(getOrCreateSymbol(Group));
GroupSym->setComdat(true);
}
return getWasmSection(Section, K, Flags, GroupSym, UniqueID, BeginSymName);
}
MCSectionWasm *MCContext::getWasmSection(const Twine &Section, SectionKind Kind,
unsigned Flags,
const MCSymbolWasm *GroupSym,
unsigned UniqueID,
const char *BeginSymName) {
StringRef Group = "";
if (GroupSym)
Group = GroupSym->getName();
// Do the lookup, if we have a hit, return it.
auto IterBool = WasmUniquingMap.insert(
std::make_pair(WasmSectionKey{Section.str(), Group, UniqueID}, nullptr));
auto &Entry = *IterBool.first;
if (!IterBool.second)
return Entry.second;
StringRef CachedName = Entry.first.SectionName;
MCSymbol *Begin = createSymbol(CachedName, true, false);
Symbols[Begin->getName()] = Begin;
cast<MCSymbolWasm>(Begin)->setType(wasm::WASM_SYMBOL_TYPE_SECTION);
MCSectionWasm *Result = new (WasmAllocator.Allocate())
MCSectionWasm(CachedName, Kind, Flags, GroupSym, UniqueID, Begin);
Entry.second = Result;
auto *F = new MCDataFragment();
Result->getFragmentList().insert(Result->begin(), F);
F->setParent(Result);
Begin->setFragment(F);
return Result;
}
MCSectionXCOFF *MCContext::getXCOFFSection(
StringRef Section, SectionKind Kind,
Optional<XCOFF::CsectProperties> CsectProp, bool MultiSymbolsAllowed,
const char *BeginSymName,
Optional<XCOFF::DwarfSectionSubtypeFlags> DwarfSectionSubtypeFlags) {
bool IsDwarfSec = DwarfSectionSubtypeFlags.hasValue();
assert((IsDwarfSec != CsectProp.hasValue()) && "Invalid XCOFF section!");
// Do the lookup. If we have a hit, return it.
auto IterBool = XCOFFUniquingMap.insert(std::make_pair(
IsDwarfSec
? XCOFFSectionKey(Section.str(), DwarfSectionSubtypeFlags.getValue())
: XCOFFSectionKey(Section.str(), CsectProp->MappingClass),
nullptr));
auto &Entry = *IterBool.first;
if (!IterBool.second) {
MCSectionXCOFF *ExistedEntry = Entry.second;
if (ExistedEntry->isMultiSymbolsAllowed() != MultiSymbolsAllowed)
report_fatal_error("section's multiply symbols policy does not match");
return ExistedEntry;
}
// Otherwise, return a new section.
StringRef CachedName = Entry.first.SectionName;
MCSymbolXCOFF *QualName = nullptr;
// Debug section don't have storage class attribute.
if (IsDwarfSec)
QualName = cast<MCSymbolXCOFF>(getOrCreateSymbol(CachedName));
else
QualName = cast<MCSymbolXCOFF>(getOrCreateSymbol(
CachedName + "[" +
XCOFF::getMappingClassString(CsectProp->MappingClass) + "]"));
MCSymbol *Begin = nullptr;
if (BeginSymName)
Begin = createTempSymbol(BeginSymName, false);
// QualName->getUnqualifiedName() and CachedName are the same except when
// CachedName contains invalid character(s) such as '$' for an XCOFF symbol.
MCSectionXCOFF *Result = nullptr;
if (IsDwarfSec)
Result = new (XCOFFAllocator.Allocate())
MCSectionXCOFF(QualName->getUnqualifiedName(), Kind, QualName,
DwarfSectionSubtypeFlags.getValue(), Begin, CachedName,
MultiSymbolsAllowed);
else
Result = new (XCOFFAllocator.Allocate())
MCSectionXCOFF(QualName->getUnqualifiedName(), CsectProp->MappingClass,
CsectProp->Type, Kind, QualName, Begin, CachedName,
MultiSymbolsAllowed);
Entry.second = Result;
auto *F = new MCDataFragment();
Result->getFragmentList().insert(Result->begin(), F);
F->setParent(Result);
if (Begin)
Begin->setFragment(F);
return Result;
}
MCSubtargetInfo &MCContext::getSubtargetCopy(const MCSubtargetInfo &STI) {
return *new (MCSubtargetAllocator.Allocate()) MCSubtargetInfo(STI);
}
void MCContext::addDebugPrefixMapEntry(const std::string &From,
const std::string &To) {
DebugPrefixMap.insert(std::make_pair(From, To));
}
void MCContext::RemapDebugPaths() {
const auto &DebugPrefixMap = this->DebugPrefixMap;
if (DebugPrefixMap.empty())
return;
const auto RemapDebugPath = [&DebugPrefixMap](std::string &Path) {
SmallString<256> P(Path);
for (const auto &Entry : DebugPrefixMap) {
if (llvm::sys::path::replace_path_prefix(P, Entry.first, Entry.second)) {
Path = P.str().str();
break;
}
}
};
// Remap compilation directory.
std::string CompDir = std::string(CompilationDir.str());
RemapDebugPath(CompDir);
CompilationDir = CompDir;
// Remap MCDwarfDirs in all compilation units.
for (auto &CUIDTablePair : MCDwarfLineTablesCUMap)
for (auto &Dir : CUIDTablePair.second.getMCDwarfDirs())
RemapDebugPath(Dir);
}
//===----------------------------------------------------------------------===//
// Dwarf Management
//===----------------------------------------------------------------------===//
void MCContext::setGenDwarfRootFile(StringRef InputFileName, StringRef Buffer) {
// MCDwarf needs the root file as well as the compilation directory.
// If we find a '.file 0' directive that will supersede these values.
Optional<MD5::MD5Result> Cksum;
if (getDwarfVersion() >= 5) {
MD5 Hash;
MD5::MD5Result Sum;
Hash.update(Buffer);
Hash.final(Sum);
Cksum = Sum;
}
// Canonicalize the root filename. It cannot be empty, and should not
// repeat the compilation dir.
// The MCContext ctor initializes MainFileName to the name associated with
// the SrcMgr's main file ID, which might be the same as InputFileName (and
// possibly include directory components).
// Or, MainFileName might have been overridden by a -main-file-name option,
// which is supposed to be just a base filename with no directory component.
// So, if the InputFileName and MainFileName are not equal, assume
// MainFileName is a substitute basename and replace the last component.
SmallString<1024> FileNameBuf = InputFileName;
if (FileNameBuf.empty() || FileNameBuf == "-")
FileNameBuf = "<stdin>";
if (!getMainFileName().empty() && FileNameBuf != getMainFileName()) {
llvm::sys::path::remove_filename(FileNameBuf);
llvm::sys::path::append(FileNameBuf, getMainFileName());
}
StringRef FileName = FileNameBuf;
if (FileName.consume_front(getCompilationDir()))
if (llvm::sys::path::is_separator(FileName.front()))
FileName = FileName.drop_front();
assert(!FileName.empty());
setMCLineTableRootFile(
/*CUID=*/0, getCompilationDir(), FileName, Cksum, None);
}
/// getDwarfFile - takes a file name and 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.
Expected<unsigned> MCContext::getDwarfFile(StringRef Directory,
StringRef FileName,
unsigned FileNumber,
Optional<MD5::MD5Result> Checksum,
Optional<StringRef> Source,
unsigned CUID) {
MCDwarfLineTable &Table = MCDwarfLineTablesCUMap[CUID];
return Table.tryGetFile(Directory, FileName, Checksum, Source, DwarfVersion,
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 MCDwarfLineTable &LineTable = getMCDwarfLineTable(CUID);
if (FileNumber == 0)
return getDwarfVersion() >= 5;
if (FileNumber >= LineTable.getMCDwarfFiles().size())
return false;
return !LineTable.getMCDwarfFiles()[FileNumber].Name.empty();
}
/// Remove empty sections from SectionsForRanges, to avoid generating
/// useless debug info for them.
void MCContext::finalizeDwarfSections(MCStreamer &MCOS) {
SectionsForRanges.remove_if(
[&](MCSection *Sec) { return !MCOS.mayHaveInstructions(*Sec); });
}
CodeViewContext &MCContext::getCVContext() {
if (!CVContext.get())
CVContext.reset(new CodeViewContext);
return *CVContext.get();
}
//===----------------------------------------------------------------------===//
// Error Reporting
//===----------------------------------------------------------------------===//
void MCContext::diagnose(const SMDiagnostic &SMD) {
assert(DiagHandler && "MCContext::DiagHandler is not set");
bool UseInlineSrcMgr = false;
const SourceMgr *SMP = nullptr;
if (SrcMgr) {
SMP = SrcMgr;
} else if (InlineSrcMgr) {
SMP = InlineSrcMgr.get();
UseInlineSrcMgr = true;
} else
llvm_unreachable("Either SourceMgr should be available");
DiagHandler(SMD, UseInlineSrcMgr, *SMP, LocInfos);
}
void MCContext::reportCommon(
SMLoc Loc,
std::function<void(SMDiagnostic &, const SourceMgr *)> GetMessage) {
// * MCContext::SrcMgr is null when the MC layer emits machine code for input
// other than assembly file, say, for .c/.cpp/.ll/.bc.
// * MCContext::InlineSrcMgr is null when the inline asm is not used.
// * A default SourceMgr is needed for diagnosing when both MCContext::SrcMgr
// and MCContext::InlineSrcMgr are null.
SourceMgr SM;
const SourceMgr *SMP = &SM;
bool UseInlineSrcMgr = false;
// FIXME: Simplify these by combining InlineSrcMgr & SrcMgr.
// For MC-only execution, only SrcMgr is used;
// For non MC-only execution, InlineSrcMgr is only ctor'd if there is
// inline asm in the IR.
if (Loc.isValid()) {
if (SrcMgr) {
SMP = SrcMgr;
} else if (InlineSrcMgr) {
SMP = InlineSrcMgr.get();
UseInlineSrcMgr = true;
} else
llvm_unreachable("Either SourceMgr should be available");
}
SMDiagnostic D;
GetMessage(D, SMP);
DiagHandler(D, UseInlineSrcMgr, *SMP, LocInfos);
}
void MCContext::reportError(SMLoc Loc, const Twine &Msg) {
HadError = true;
reportCommon(Loc, [&](SMDiagnostic &D, const SourceMgr *SMP) {
D = SMP->GetMessage(Loc, SourceMgr::DK_Error, Msg);
});
}
void MCContext::reportWarning(SMLoc Loc, const Twine &Msg) {
if (TargetOptions && TargetOptions->MCNoWarn)
return;
if (TargetOptions && TargetOptions->MCFatalWarnings) {
reportError(Loc, Msg);
} else {
reportCommon(Loc, [&](SMDiagnostic &D, const SourceMgr *SMP) {
D = SMP->GetMessage(Loc, SourceMgr::DK_Warning, Msg);
});
}
}
void MCContext::reportFatalError(SMLoc Loc, const Twine &Msg) {
reportError(Loc, 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);
}
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