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llvm-project/llvm/lib/MC/MCContext.cpp
aengelke 3b8b102268
[MC] Make ELFEntrySizeMap a DenseMap (#91728) 
There is no need for an ordered std::map and also no need to duplicate
the section name, which is owned by the ELFSectionKey. Therefore, use a
DenseMap instead and don't copy the string. As a further, minor
performance optimization, avoid the hash table lookup in
isELFGenericMergeableSection when the section name was just added.

This slightly improves compilation performance in our application, where
we occasionally compile many small object files.
2024-05-14 11:38:38 +02:00

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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/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/Wasm.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/MCInst.h"
#include "llvm/MC/MCLabel.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSectionDXContainer.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionGOFF.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCSectionSPIRV.h"
#include "llvm/MC/MCSectionWasm.h"
#include "llvm/MC/MCSectionXCOFF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.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/MCTargetOptions.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/SMLoc.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstdlib>
#include <optional>
#include <tuple>
#include <utility>
using namespace llvm;
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, StringRef Swift5ReflSegmentName)
: Swift5ReflectionSegmentName(Swift5ReflSegmentName), 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 = TargetOptions ? TargetOptions->AsSecureLogFile : "";
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() && !TheTriple.isUEFI())
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::DXContainer:
Env = IsDXContainer;
break;
case Triple::SPIRV:
Env = IsSPIRV;
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();
DXCAllocator.DestroyAll();
ELFAllocator.DestroyAll();
GOFFAllocator.DestroyAll();
MachOAllocator.DestroyAll();
WasmAllocator.DestroyAll();
XCOFFAllocator.DestroyAll();
MCInstAllocator.DestroyAll();
SPIRVAllocator.DestroyAll();
WasmSignatureAllocator.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();
DXCUniquingMap.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(const Twine &FuncName,
unsigned Idx) {
return getOrCreateSymbol(MAI->getPrivateGlobalPrefix() + FuncName +
"$frame_escape_" + Twine(Idx));
}
MCSymbol *MCContext::getOrCreateParentFrameOffsetSymbol(const Twine &FuncName) {
return getOrCreateSymbol(MAI->getPrivateGlobalPrefix() + FuncName +
"$parent_frame_offset");
}
MCSymbol *MCContext::getOrCreateLSDASymbol(const Twine &FuncName) {
return getOrCreateSymbol(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);
case MCContext::IsDXContainer:
break;
case MCContext::IsSPIRV:
return new (Name, *this)
MCSymbol(MCSymbol::SymbolKindUnset, 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.starts_with(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() {
return createLinkerPrivateSymbol("tmp");
}
MCSymbol *MCContext::createLinkerPrivateSymbol(const Twine &Name) {
SmallString<128> NameSV;
raw_svector_ostream(NameSV) << MAI->getLinkerPrivateGlobalPrefix() << Name;
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, const Twine &Sym,
uint64_t Val) {
auto Symbol = getOrCreateSymbol(Sym);
Streamer.emitAssignment(Symbol, MCConstantExpr::create(Val, *this));
}
void MCContext::registerInlineAsmLabel(MCSymbol *Sym) {
InlineAsmUsedLabelNames[Sym->getName()] = Sym;
}
wasm::WasmSignature *MCContext::createWasmSignature() {
return new (WasmSignatureAllocator.Allocate()) wasm::WasmSignature;
}
MCSymbolXCOFF *
MCContext::createXCOFFSymbolImpl(const StringMapEntry<bool> *Name,
bool IsTemporary) {
if (!Name)
return new (nullptr, *this) MCSymbolXCOFF(nullptr, IsTemporary);
StringRef OriginalName = Name->first();
if (OriginalName.starts_with("._Renamed..") ||
OriginalName.starts_with("_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.starts_with(".");
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;
}
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 if (~Flags & ELF::SHF_WRITE)
Kind = SectionKind::getReadOnly();
else if (Flags & ELF::SHF_TLS)
Kind = (Type & ELF::SHT_NOBITS) ? SectionKind::getThreadBSS()
: SectionKind::getThreadData();
else
// Default to `SectionKind::getText()`. This is the default for gas as
// well. The condition that falls into this case is where we do not have any
// section flags and must infer a classification rather than where we have
// section flags (i.e. this is not that SHF_EXECINSTR is unset bur rather it
// is unknown).
Kind = llvm::StringSwitch<SectionKind>(CachedName)
.Case(".bss", SectionKind::getBSS())
.StartsWith(".bss.", SectionKind::getBSS())
.StartsWith(".gnu.linkonce.b.", SectionKind::getBSS())
.StartsWith(".llvm.linkonce.b.", SectionKind::getBSS())
.Case(".data", SectionKind::getData())
.Case(".data1", SectionKind::getData())
.Case(".data.rel.ro", SectionKind::getReadOnlyWithRel())
.StartsWith(".data.", SectionKind::getData())
.Case(".rodata", SectionKind::getReadOnly())
.Case(".rodata1", SectionKind::getReadOnly())
.StartsWith(".rodata.", SectionKind::getReadOnly())
.Case(".tbss", SectionKind::getThreadBSS())
.StartsWith(".tbss.", SectionKind::getThreadData())
.StartsWith(".gnu.linkonce.tb.", SectionKind::getThreadData())
.StartsWith(".llvm.linkonce.tb.", SectionKind::getThreadData())
.Case(".tdata", SectionKind::getThreadData())
.StartsWith(".tdata.", SectionKind::getThreadData())
.StartsWith(".gnu.linkonce.td.", SectionKind::getThreadData())
.StartsWith(".llvm.linkonce.td.", SectionKind::getThreadData())
.StartsWith(".debug_", SectionKind::getMetadata())
.Default(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 (UniqueID == GenericSectionID) {
ELFSeenGenericMergeableSections.insert(SectionName);
// Minor performance optimization: avoid hash map lookup in
// isELFGenericMergeableSection, which will return true for SectionName.
IsMergeable = true;
}
// 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(
std::make_tuple(SectionName, Flags, EntrySize), UniqueID));
}
}
bool MCContext::isELFImplicitMergeableSectionNamePrefix(StringRef SectionName) {
return SectionName.starts_with(".rodata.str") ||
SectionName.starts_with(".rodata.cst");
}
bool MCContext::isELFGenericMergeableSection(StringRef SectionName) {
return isELFImplicitMergeableSectionNamePrefix(SectionName) ||
ELFSeenGenericMergeableSections.count(SectionName);
}
std::optional<unsigned>
MCContext::getELFUniqueIDForEntsize(StringRef SectionName, unsigned Flags,
unsigned EntrySize) {
auto I = ELFEntrySizeMap.find(std::make_tuple(SectionName, Flags, EntrySize));
return (I != ELFEntrySizeMap.end()) ? std::optional<unsigned>(I->second)
: std::nullopt;
}
MCSectionGOFF *MCContext::getGOFFSection(StringRef Section, SectionKind Kind,
MCSection *Parent,
const MCExpr *SubsectionId) {
// Do the lookup. If we don't have a hit, return a new section.
auto IterBool =
GOFFUniquingMap.insert(std::make_pair(Section.str(), nullptr));
auto Iter = IterBool.first;
if (!IterBool.second)
return Iter->second;
StringRef CachedName = Iter->first;
MCSectionGOFF *GOFFSection = new (GOFFAllocator.Allocate())
MCSectionGOFF(CachedName, Kind, Parent, SubsectionId);
Iter->second = GOFFSection;
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;
}
bool MCContext::hasXCOFFSection(StringRef Section,
XCOFF::CsectProperties CsectProp) const {
return XCOFFUniquingMap.count(
XCOFFSectionKey(Section.str(), CsectProp.MappingClass)) != 0;
}
MCSectionXCOFF *MCContext::getXCOFFSection(
StringRef Section, SectionKind Kind,
std::optional<XCOFF::CsectProperties> CsectProp, bool MultiSymbolsAllowed,
const char *BeginSymName,
std::optional<XCOFF::DwarfSectionSubtypeFlags> DwarfSectionSubtypeFlags) {
bool IsDwarfSec = DwarfSectionSubtypeFlags.has_value();
assert((IsDwarfSec != CsectProp.has_value()) && "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)
: 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, 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);
// We might miss calculating the symbols difference as absolute value before
// adding fixups when symbol_A without the fragment set is the csect itself
// and symbol_B is in it.
// TODO: Currently we only set the fragment for XMC_PR csects because we don't
// have other cases that hit this problem yet.
if (!IsDwarfSec && CsectProp->MappingClass == XCOFF::XMC_PR)
QualName->setFragment(F);
return Result;
}
MCSectionSPIRV *MCContext::getSPIRVSection() {
MCSymbol *Begin = nullptr;
MCSectionSPIRV *Result = new (SPIRVAllocator.Allocate())
MCSectionSPIRV(SectionKind::getText(), Begin);
auto *F = new MCDataFragment();
Result->getFragmentList().insert(Result->begin(), F);
F->setParent(Result);
return Result;
}
MCSectionDXContainer *MCContext::getDXContainerSection(StringRef Section,
SectionKind K) {
// Do the lookup, if we have a hit, return it.
auto ItInsertedPair = DXCUniquingMap.try_emplace(Section);
if (!ItInsertedPair.second)
return ItInsertedPair.first->second;
auto MapIt = ItInsertedPair.first;
// Grab the name from the StringMap. Since the Section is going to keep a
// copy of this StringRef we need to make sure the underlying string stays
// alive as long as we need it.
StringRef Name = MapIt->first();
MapIt->second =
new (DXCAllocator.Allocate()) MCSectionDXContainer(Name, K, nullptr);
// The first fragment will store the header
auto *F = new MCDataFragment();
MapIt->second->getFragmentList().insert(MapIt->second->begin(), F);
F->setParent(MapIt->second);
return MapIt->second;
}
MCSubtargetInfo &MCContext::getSubtargetCopy(const MCSubtargetInfo &STI) {
return *new (MCSubtargetAllocator.Allocate()) MCSubtargetInfo(STI);
}
void MCContext::addDebugPrefixMapEntry(const std::string &From,
const std::string &To) {
DebugPrefixMap.emplace_back(From, To);
}
void MCContext::remapDebugPath(SmallVectorImpl<char> &Path) {
for (const auto &[From, To] : llvm::reverse(DebugPrefixMap))
if (llvm::sys::path::replace_path_prefix(Path, From, To))
break;
}
void MCContext::RemapDebugPaths() {
const auto &DebugPrefixMap = this->DebugPrefixMap;
if (DebugPrefixMap.empty())
return;
// Remap compilation directory.
remapDebugPath(CompilationDir);
// Remap MCDwarfDirs and RootFile.Name in all compilation units.
SmallString<256> P;
for (auto &CUIDTablePair : MCDwarfLineTablesCUMap) {
for (auto &Dir : CUIDTablePair.second.getMCDwarfDirs()) {
P = Dir;
remapDebugPath(P);
Dir = std::string(P);
}
// Used by DW_TAG_compile_unit's DT_AT_name and DW_TAG_label's
// DW_AT_decl_file for DWARF v5 generated for assembly source.
P = CUIDTablePair.second.getRootFile().Name;
remapDebugPath(P);
CUIDTablePair.second.getRootFile().Name = std::string(P);
}
}
//===----------------------------------------------------------------------===//
// Dwarf Management
//===----------------------------------------------------------------------===//
EmitDwarfUnwindType MCContext::emitDwarfUnwindInfo() const {
if (!TargetOptions)
return EmitDwarfUnwindType::Default;
return TargetOptions->EmitDwarfUnwind;
}
bool MCContext::emitCompactUnwindNonCanonical() const {
if (TargetOptions)
return TargetOptions->EmitCompactUnwindNonCanonical;
return false;
}
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.
std::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, std::nullopt);
}
/// 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,
std::optional<MD5::MD5Result> Checksum,
std::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)
CVContext.reset(new CodeViewContext);
return *CVContext;
}
//===----------------------------------------------------------------------===//
// 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);
});
}
}
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