-//===- lib/MC/MCELFStreamer.cpp - ELF Object Output ------------===//
+//===- lib/MC/MCELFStreamer.cpp - ELF Object Output -----------------------===//
//
// The LLVM Compiler Infrastructure
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCELFStreamer.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCELFSymbolFlags.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCObjectStreamer.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSectionELF.h"
using namespace llvm;
-
-inline void MCELFStreamer::SetSection(StringRef Section, unsigned Type,
- unsigned Flags, SectionKind Kind) {
- SwitchSection(getContext().getELFSection(Section, Type, Flags, Kind));
+MCELFStreamer::~MCELFStreamer() {
}
-inline void MCELFStreamer::SetSectionData() {
- SetSection(".data",
- ELF::SHT_PROGBITS,
- ELF::SHF_WRITE | ELF::SHF_ALLOC,
- SectionKind::getDataRel());
- EmitCodeAlignment(4, 0);
-}
+void MCELFStreamer::InitSections(bool NoExecStack) {
+ // This emulates the same behavior of GNU as. This makes it easier
+ // to compare the output as the major sections are in the same order.
+ MCContext &Ctx = getContext();
+ SwitchSection(Ctx.getObjectFileInfo()->getTextSection());
+ EmitCodeAlignment(4);
-inline void MCELFStreamer::SetSectionText() {
- SetSection(".text",
- ELF::SHT_PROGBITS,
- ELF::SHF_EXECINSTR | ELF::SHF_ALLOC,
- SectionKind::getText());
- EmitCodeAlignment(4, 0);
-}
+ SwitchSection(Ctx.getObjectFileInfo()->getDataSection());
+ EmitCodeAlignment(4);
-inline void MCELFStreamer::SetSectionBss() {
- SetSection(".bss",
- ELF::SHT_NOBITS,
- ELF::SHF_WRITE | ELF::SHF_ALLOC,
- SectionKind::getBSS());
- EmitCodeAlignment(4, 0);
-}
+ SwitchSection(Ctx.getObjectFileInfo()->getBSSSection());
+ EmitCodeAlignment(4);
-MCELFStreamer::~MCELFStreamer() {
-}
+ SwitchSection(Ctx.getObjectFileInfo()->getTextSection());
-void MCELFStreamer::InitSections() {
- // This emulates the same behavior of GNU as. This makes it easier
- // to compare the output as the major sections are in the same order.
- SetSectionText();
- SetSectionData();
- SetSectionBss();
- SetSectionText();
+ if (NoExecStack)
+ SwitchSection(Ctx.getAsmInfo()->getNonexecutableStackSection(Ctx));
}
void MCELFStreamer::EmitLabel(MCSymbol *Symbol) {
MCELF::SetType(SD, ELF::STT_TLS);
}
-void MCELFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
- EmitLabel(Symbol);
-}
-
void MCELFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
+ // Let the target do whatever target specific stuff it needs to do.
+ getAssembler().getBackend().handleAssemblerFlag(Flag);
+ // Do any generic stuff we need to do.
switch (Flag) {
case MCAF_SyntaxUnified: return; // no-op here.
case MCAF_Code16: return; // Change parsing mode; no-op here.
llvm_unreachable("invalid assembler flag!");
}
-void MCELFStreamer::ChangeSection(const MCSection *Section) {
+void MCELFStreamer::ChangeSection(const MCSection *Section,
+ const MCExpr *Subsection) {
MCSectionData *CurSection = getCurrentSectionData();
if (CurSection && CurSection->isBundleLocked())
report_fatal_error("Unterminated .bundle_lock when changing a section");
- const MCSymbol *Grp = static_cast<const MCSectionELF *>(Section)->getGroup();
+
+ MCAssembler &Asm = getAssembler();
+ auto *SectionELF = static_cast<const MCSectionELF *>(Section);
+ const MCSymbol *Grp = SectionELF->getGroup();
if (Grp)
- getAssembler().getOrCreateSymbolData(*Grp);
- this->MCObjectStreamer::ChangeSection(Section);
+ Asm.getOrCreateSymbolData(*Grp);
+
+ this->MCObjectStreamer::ChangeSection(Section, Subsection);
+ MCSymbol *SectionSymbol = getContext().getOrCreateSectionSymbol(*SectionELF);
+ if (SectionSymbol->isUndefined()) {
+ EmitLabel(SectionSymbol);
+ MCELF::SetType(Asm.getSymbolData(*SectionSymbol), ELF::STT_SECTION);
+ }
}
void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {
getAssembler().getOrCreateSymbolData(*Symbol);
- MCSymbolData &AliasSD = getAssembler().getOrCreateSymbolData(*Alias);
- AliasSD.setFlags(AliasSD.getFlags() | ELF_Other_Weakref);
- const MCExpr *Value = MCSymbolRefExpr::Create(Symbol, getContext());
+ const MCExpr *Value = MCSymbolRefExpr::Create(
+ Symbol, MCSymbolRefExpr::VK_WEAKREF, getContext());
Alias->setVariableValue(Value);
}
-void MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
- MCSymbolAttr Attribute) {
+// When GNU as encounters more than one .type declaration for an object it seems
+// to use a mechanism similar to the one below to decide which type is actually
+// used in the object file. The greater of T1 and T2 is selected based on the
+// following ordering:
+// STT_NOTYPE < STT_OBJECT < STT_FUNC < STT_GNU_IFUNC < STT_TLS < anything else
+// If neither T1 < T2 nor T2 < T1 according to this ordering, use T2 (the user
+// provided type).
+static unsigned CombineSymbolTypes(unsigned T1, unsigned T2) {
+ unsigned TypeOrdering[] = {ELF::STT_NOTYPE, ELF::STT_OBJECT, ELF::STT_FUNC,
+ ELF::STT_GNU_IFUNC, ELF::STT_TLS};
+ for (unsigned i = 0; i != array_lengthof(TypeOrdering); ++i) {
+ if (T1 == TypeOrdering[i])
+ return T2;
+ if (T2 == TypeOrdering[i])
+ return T1;
+ }
+
+ return T2;
+}
+
+bool MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
+ MCSymbolAttr Attribute) {
// Indirect symbols are handled differently, to match how 'as' handles
// them. This makes writing matching .o files easier.
if (Attribute == MCSA_IndirectSymbol) {
ISD.Symbol = Symbol;
ISD.SectionData = getCurrentSectionData();
getAssembler().getIndirectSymbols().push_back(ISD);
- return;
+ return true;
}
// Adding a symbol attribute always introduces the symbol, note that an
case MCSA_WeakDefAutoPrivate:
case MCSA_Invalid:
case MCSA_IndirectSymbol:
- llvm_unreachable("Invalid symbol attribute for ELF!");
+ return false;
case MCSA_NoDeadStrip:
case MCSA_ELF_TypeGnuUniqueObject:
break;
case MCSA_ELF_TypeFunction:
- MCELF::SetType(SD, ELF::STT_FUNC);
+ MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
+ ELF::STT_FUNC));
break;
case MCSA_ELF_TypeIndFunction:
- MCELF::SetType(SD, ELF::STT_GNU_IFUNC);
+ MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
+ ELF::STT_GNU_IFUNC));
break;
case MCSA_ELF_TypeObject:
- MCELF::SetType(SD, ELF::STT_OBJECT);
+ MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
+ ELF::STT_OBJECT));
break;
case MCSA_ELF_TypeTLS:
- MCELF::SetType(SD, ELF::STT_TLS);
+ MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
+ ELF::STT_TLS));
break;
case MCSA_ELF_TypeCommon:
- MCELF::SetType(SD, ELF::STT_COMMON);
+ // TODO: Emit these as a common symbol.
+ MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
+ ELF::STT_OBJECT));
break;
case MCSA_ELF_TypeNoType:
- MCELF::SetType(SD, ELF::STT_NOTYPE);
+ MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
+ ELF::STT_NOTYPE));
break;
case MCSA_Protected:
MCELF::SetVisibility(SD, ELF::STV_INTERNAL);
break;
}
+
+ return true;
}
void MCELFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
ELF::SHF_WRITE |
ELF::SHF_ALLOC,
SectionKind::getBSS());
- Symbol->setSection(*Section);
+
+ AssignSection(Symbol, Section);
struct LocalCommon L = {&SD, Size, ByteAlignment};
LocalCommons.push_back(L);
}
void MCELFStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
- unsigned AddrSpace) {
+ const SMLoc &Loc) {
if (getCurrentSectionData()->isBundleLocked())
report_fatal_error("Emitting values inside a locked bundle is forbidden");
fixSymbolsInTLSFixups(Value);
- MCObjectStreamer::EmitValueImpl(Value, Size, AddrSpace);
+ MCObjectStreamer::EmitValueImpl(Value, Size, Loc);
}
void MCELFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
ValueSize, MaxBytesToEmit);
}
-
-// Add a symbol for the file name of this module. This is the second
-// entry in the module's symbol table (the first being the null symbol).
+// Add a symbol for the file name of this module. They start after the
+// null symbol and don't count as normal symbol, i.e. a non-STT_FILE symbol
+// with the same name may appear.
void MCELFStreamer::EmitFileDirective(StringRef Filename) {
- MCSymbol *Symbol = getAssembler().getContext().GetOrCreateSymbol(Filename);
- Symbol->setSection(*getCurrentSection());
- Symbol->setAbsolute();
-
- MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
-
- SD.setFlags(ELF_STT_File | ELF_STB_Local | ELF_STV_Default);
+ getAssembler().addFileName(Filename);
+}
+
+void MCELFStreamer::EmitIdent(StringRef IdentString) {
+ const MCSection *Comment = getAssembler().getContext().getELFSection(
+ ".comment", ELF::SHT_PROGBITS, ELF::SHF_MERGE | ELF::SHF_STRINGS,
+ SectionKind::getReadOnly(), 1, "");
+ PushSection();
+ SwitchSection(Comment);
+ if (!SeenIdent) {
+ EmitIntValue(0, 1);
+ SeenIdent = true;
+ }
+ EmitBytes(IdentString);
+ EmitIntValue(0, 1);
+ PopSection();
}
-void MCELFStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) {
+void MCELFStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) {
switch (expr->getKind()) {
- case MCExpr::Target: llvm_unreachable("Can't handle target exprs yet!");
+ case MCExpr::Target:
+ cast<MCTargetExpr>(expr)->fixELFSymbolsInTLSFixups(getAssembler());
+ break;
case MCExpr::Constant:
break;
case MCSymbolRefExpr::VK_TLSLDM:
case MCSymbolRefExpr::VK_TPOFF:
case MCSymbolRefExpr::VK_DTPOFF:
- case MCSymbolRefExpr::VK_ARM_TLSGD:
- case MCSymbolRefExpr::VK_ARM_TPOFF:
- case MCSymbolRefExpr::VK_ARM_GOTTPOFF:
case MCSymbolRefExpr::VK_Mips_TLSGD:
case MCSymbolRefExpr::VK_Mips_GOTTPREL:
case MCSymbolRefExpr::VK_Mips_TPREL_HI:
case MCSymbolRefExpr::VK_Mips_TPREL_LO:
+ case MCSymbolRefExpr::VK_PPC_DTPMOD:
+ case MCSymbolRefExpr::VK_PPC_TPREL:
+ case MCSymbolRefExpr::VK_PPC_TPREL_LO:
+ case MCSymbolRefExpr::VK_PPC_TPREL_HI:
+ case MCSymbolRefExpr::VK_PPC_TPREL_HA:
+ case MCSymbolRefExpr::VK_PPC_TPREL_HIGHER:
+ case MCSymbolRefExpr::VK_PPC_TPREL_HIGHERA:
+ case MCSymbolRefExpr::VK_PPC_TPREL_HIGHEST:
+ case MCSymbolRefExpr::VK_PPC_TPREL_HIGHESTA:
+ case MCSymbolRefExpr::VK_PPC_DTPREL:
+ case MCSymbolRefExpr::VK_PPC_DTPREL_LO:
+ case MCSymbolRefExpr::VK_PPC_DTPREL_HI:
+ case MCSymbolRefExpr::VK_PPC_DTPREL_HA:
+ case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHER:
+ case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHERA:
+ case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHEST:
+ case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHESTA:
+ case MCSymbolRefExpr::VK_PPC_GOT_TPREL:
+ case MCSymbolRefExpr::VK_PPC_GOT_TPREL_LO:
+ case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HI:
+ case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HA:
+ case MCSymbolRefExpr::VK_PPC_GOT_DTPREL:
+ case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_LO:
+ case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HI:
+ case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HA:
+ case MCSymbolRefExpr::VK_PPC_TLS:
+ case MCSymbolRefExpr::VK_PPC_GOT_TLSGD:
+ case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_LO:
+ case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HI:
+ case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HA:
+ case MCSymbolRefExpr::VK_PPC_TLSGD:
+ case MCSymbolRefExpr::VK_PPC_GOT_TLSLD:
+ case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO:
+ case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HI:
+ case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HA:
+ case MCSymbolRefExpr::VK_PPC_TLSLD:
break;
}
MCSymbolData &SD = getAssembler().getOrCreateSymbolData(symRef.getSymbol());
}
}
-void MCELFStreamer::EmitInstToFragment(const MCInst &Inst) {
- this->MCObjectStreamer::EmitInstToFragment(Inst);
- MCInstFragment &F = *cast<MCInstFragment>(getCurrentFragment());
+void MCELFStreamer::EmitInstToFragment(const MCInst &Inst,
+ const MCSubtargetInfo &STI) {
+ this->MCObjectStreamer::EmitInstToFragment(Inst, STI);
+ MCRelaxableFragment &F = *cast<MCRelaxableFragment>(getCurrentFragment());
for (unsigned i = 0, e = F.getFixups().size(); i != e; ++i)
fixSymbolsInTLSFixups(F.getFixups()[i].getValue());
}
-void MCELFStreamer::EmitInstToData(const MCInst &Inst) {
+void MCELFStreamer::EmitInstToData(const MCInst &Inst,
+ const MCSubtargetInfo &STI) {
MCAssembler &Assembler = getAssembler();
SmallVector<MCFixup, 4> Fixups;
SmallString<256> Code;
raw_svector_ostream VecOS(Code);
- Assembler.getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
+ Assembler.getEmitter().EncodeInstruction(Inst, VecOS, Fixups, STI);
VecOS.flush();
for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
// data fragment).
//
// If bundling is enabled:
- // - If we're not in a bundle-locked group, emit the instruction into a data
- // fragment of its own.
+ // - If we're not in a bundle-locked group, emit the instruction into a
+ // fragment of its own. If there are no fixups registered for the
+ // instruction, emit a MCCompactEncodedInstFragment. Otherwise, emit a
+ // MCDataFragment.
// - If we're in a bundle-locked group, append the instruction to the current
// data fragment because we want all the instructions in a group to get into
// the same fragment. Be careful not to do that for the first instruction in
if (Assembler.isBundlingEnabled()) {
MCSectionData *SD = getCurrentSectionData();
if (SD->isBundleLocked() && !SD->isBundleGroupBeforeFirstInst())
- DF = getOrCreateDataFragment();
- else
- DF = new MCDataFragment(SD);
+ // If we are bundle-locked, we re-use the current fragment.
+ // The bundle-locking directive ensures this is a new data fragment.
+ DF = cast<MCDataFragment>(getCurrentFragment());
+ else if (!SD->isBundleLocked() && Fixups.size() == 0) {
+ // Optimize memory usage by emitting the instruction to a
+ // MCCompactEncodedInstFragment when not in a bundle-locked group and
+ // there are no fixups registered.
+ MCCompactEncodedInstFragment *CEIF = new MCCompactEncodedInstFragment();
+ insert(CEIF);
+ CEIF->getContents().append(Code.begin(), Code.end());
+ return;
+ } else {
+ DF = new MCDataFragment();
+ insert(DF);
+ }
+ if (SD->getBundleLockState() == MCSectionData::BundleLockedAlignToEnd) {
+ // If this fragment is for a group marked "align_to_end", set a flag
+ // in the fragment. This can happen after the fragment has already been
+ // created if there are nested bundle_align groups and an inner one
+ // is the one marked align_to_end.
+ DF->setAlignToBundleEnd(true);
+ }
// We're now emitting an instruction in a bundle group, so this flag has
// to be turned off.
void MCELFStreamer::EmitBundleAlignMode(unsigned AlignPow2) {
assert(AlignPow2 <= 30 && "Invalid bundle alignment");
MCAssembler &Assembler = getAssembler();
- if (Assembler.getBundleAlignSize() == 0 && AlignPow2 > 0)
- Assembler.setBundleAlignSize(1 << AlignPow2);
+ if (AlignPow2 > 0 && (Assembler.getBundleAlignSize() == 0 ||
+ Assembler.getBundleAlignSize() == 1U << AlignPow2))
+ Assembler.setBundleAlignSize(1U << AlignPow2);
else
- report_fatal_error(".bundle_align_mode should be only set once per file");
+ report_fatal_error(".bundle_align_mode cannot be changed once set");
}
-void MCELFStreamer::EmitBundleLock() {
+void MCELFStreamer::EmitBundleLock(bool AlignToEnd) {
MCSectionData *SD = getCurrentSectionData();
// Sanity checks
//
if (!getAssembler().isBundlingEnabled())
report_fatal_error(".bundle_lock forbidden when bundling is disabled");
- else if (SD->isBundleLocked())
- report_fatal_error("Nesting of .bundle_lock is forbidden");
- SD->setBundleLocked(true);
- SD->setBundleGroupBeforeFirstInst(true);
+ if (!SD->isBundleLocked())
+ SD->setBundleGroupBeforeFirstInst(true);
+
+ SD->setBundleLockState(AlignToEnd ? MCSectionData::BundleLockedAlignToEnd :
+ MCSectionData::BundleLocked);
}
void MCELFStreamer::EmitBundleUnlock() {
else if (SD->isBundleGroupBeforeFirstInst())
report_fatal_error("Empty bundle-locked group is forbidden");
- SD->setBundleLocked(false);
+ SD->setBundleLockState(MCSectionData::NotBundleLocked);
}
-void MCELFStreamer::FinishImpl() {
- EmitFrames(true);
-
+void MCELFStreamer::Flush() {
for (std::vector<LocalCommon>::const_iterator i = LocalCommons.begin(),
e = LocalCommons.end();
i != e; ++i) {
SectData.setAlignment(ByteAlignment);
}
- this->MCObjectStreamer::FinishImpl();
+ LocalCommons.clear();
}
-void MCELFStreamer::EmitTCEntry(const MCSymbol &S) {
- // Creates a R_PPC64_TOC relocation
- MCObjectStreamer::EmitSymbolValue(&S, 8, 0);
+
+void MCELFStreamer::FinishImpl() {
+ EmitFrames(nullptr);
+
+ Flush();
+
+ this->MCObjectStreamer::FinishImpl();
}
MCStreamer *llvm::createELFStreamer(MCContext &Context, MCAsmBackend &MAB,
raw_ostream &OS, MCCodeEmitter *CE,
- bool RelaxAll, bool NoExecStack) {
+ bool RelaxAll) {
MCELFStreamer *S = new MCELFStreamer(Context, MAB, OS, CE);
if (RelaxAll)
S->getAssembler().setRelaxAll(true);
- if (NoExecStack)
- S->getAssembler().setNoExecStack(true);
return S;
}
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