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-rw-r--r--llvm/lib/MC/MCAssembler.cpp43
-rw-r--r--llvm/lib/MC/MCCodeView.cpp2
-rw-r--r--llvm/lib/MC/MCObjectFileInfo.cpp20
-rw-r--r--llvm/lib/MC/MCObjectStreamer.cpp121
-rw-r--r--llvm/lib/MC/MCSection.cpp6
-rw-r--r--llvm/lib/MC/MCWin64EH.cpp3
-rw-r--r--llvm/lib/MC/MCWinCOFFStreamer.cpp5
-rw-r--r--llvm/lib/MC/MCXCOFFStreamer.cpp12
8 files changed, 160 insertions, 52 deletions
diff --git a/llvm/lib/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp
index 8500fd1..5c8e904 100644
--- a/llvm/lib/MC/MCAssembler.cpp
+++ b/llvm/lib/MC/MCAssembler.cpp
@@ -59,7 +59,8 @@ STATISTIC(EmittedFillFragments,
"Number of emitted assembler fragments - fill");
STATISTIC(EmittedNopsFragments, "Number of emitted assembler fragments - nops");
STATISTIC(EmittedOrgFragments, "Number of emitted assembler fragments - org");
-STATISTIC(evaluateFixup, "Number of evaluated fixups");
+STATISTIC(Fixups, "Number of fixups");
+STATISTIC(FixupEvalForRelax, "Number of fixup evaluations for relaxation");
STATISTIC(ObjectBytes, "Number of emitted object file bytes");
STATISTIC(RelaxationSteps, "Number of assembler layout and relaxation steps");
STATISTIC(RelaxedInstructions, "Number of relaxed instructions");
@@ -140,9 +141,9 @@ bool MCAssembler::isThumbFunc(const MCSymbol *Symbol) const {
bool MCAssembler::evaluateFixup(const MCFragment &F, MCFixup &Fixup,
MCValue &Target, uint64_t &Value,
- bool RecordReloc,
- MutableArrayRef<char> Contents) const {
- ++stats::evaluateFixup;
+ bool RecordReloc, uint8_t *Data) const {
+ if (RecordReloc)
+ ++stats::Fixups;
// FIXME: This code has some duplication with recordRelocation. We should
// probably merge the two into a single callback that tries to evaluate a
@@ -185,7 +186,7 @@ bool MCAssembler::evaluateFixup(const MCFragment &F, MCFixup &Fixup,
if (IsResolved && mc::isRelocRelocation(Fixup.getKind()))
IsResolved = false;
- getBackend().applyFixup(F, Fixup, Target, Contents, Value, IsResolved);
+ getBackend().applyFixup(F, Fixup, Target, Data, Value, IsResolved);
return true;
}
@@ -703,21 +704,25 @@ void MCAssembler::layout() {
for (MCFixup &Fixup : F.getFixups()) {
uint64_t FixedValue;
MCValue Target;
+ assert(mc::isRelocRelocation(Fixup.getKind()) ||
+ Fixup.getOffset() <= F.getFixedSize());
+ auto *Data =
+ reinterpret_cast<uint8_t *>(Contents.data() + Fixup.getOffset());
evaluateFixup(F, Fixup, Target, FixedValue,
- /*RecordReloc=*/true, Contents);
+ /*RecordReloc=*/true, Data);
}
- if (F.getVarFixups().size()) {
- // In the variable part, fixup offsets are relative to the fixed part's
- // start. Extend the variable contents to the left to account for the
- // fixed part size.
- Contents = MutableArrayRef(F.getParent()->ContentStorage)
- .slice(F.VarContentStart - Contents.size(), F.getSize());
- for (MCFixup &Fixup : F.getVarFixups()) {
- uint64_t FixedValue;
- MCValue Target;
- evaluateFixup(F, Fixup, Target, FixedValue,
- /*RecordReloc=*/true, Contents);
- }
+ // In the variable part, fixup offsets are relative to the fixed part's
+ // start.
+ for (MCFixup &Fixup : F.getVarFixups()) {
+ uint64_t FixedValue;
+ MCValue Target;
+ assert(mc::isRelocRelocation(Fixup.getKind()) ||
+ (Fixup.getOffset() >= F.getFixedSize() &&
+ Fixup.getOffset() <= F.getSize()));
+ auto *Data = reinterpret_cast<uint8_t *>(
+ F.getVarContents().data() + (Fixup.getOffset() - F.getFixedSize()));
+ evaluateFixup(F, Fixup, Target, FixedValue,
+ /*RecordReloc=*/true, Data);
}
}
}
@@ -735,7 +740,7 @@ void MCAssembler::Finish() {
bool MCAssembler::fixupNeedsRelaxation(const MCFragment &F,
const MCFixup &Fixup) const {
- assert(getBackendPtr() && "Expected assembler backend");
+ ++stats::FixupEvalForRelax;
MCValue Target;
uint64_t Value;
bool Resolved = evaluateFixup(F, const_cast<MCFixup &>(Fixup), Target, Value,
diff --git a/llvm/lib/MC/MCCodeView.cpp b/llvm/lib/MC/MCCodeView.cpp
index 7d528a5..3a5f01c 100644
--- a/llvm/lib/MC/MCCodeView.cpp
+++ b/llvm/lib/MC/MCCodeView.cpp
@@ -695,5 +695,7 @@ void CodeViewContext::encodeDefRange(const MCAssembler &Asm,
}
Frag.setVarContents(Contents);
+ assert(Fixups.size() < 256 && "Store fixups outside of MCFragment's VarFixup "
+ "storage if the number ever exceeds 256");
Frag.setVarFixups(Fixups);
}
diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index 0069d12..393eed1 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -537,6 +537,8 @@ void MCObjectFileInfo::initELFMCObjectFileInfo(const Triple &T, bool Large) {
EHFrameSection =
Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
+ CallGraphSection = Ctx->getELFSection(".callgraph", ELF::SHT_PROGBITS, 0);
+
StackSizesSection = Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, 0);
PseudoProbeSection = Ctx->getELFSection(".pseudo_probe", DebugSecType, 0);
@@ -1121,6 +1123,24 @@ MCSection *MCObjectFileInfo::getDwarfComdatSection(const char *Name,
}
MCSection *
+MCObjectFileInfo::getCallGraphSection(const MCSection &TextSec) const {
+ if (Ctx->getObjectFileType() != MCContext::IsELF)
+ return CallGraphSection;
+
+ const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(TextSec);
+ unsigned Flags = ELF::SHF_LINK_ORDER;
+ StringRef GroupName;
+ if (const MCSymbol *Group = ElfSec.getGroup()) {
+ GroupName = Group->getName();
+ Flags |= ELF::SHF_GROUP;
+ }
+
+ return Ctx->getELFSection(".callgraph", ELF::SHT_PROGBITS, Flags, 0,
+ GroupName, true, ElfSec.getUniqueID(),
+ cast<MCSymbolELF>(TextSec.getBeginSymbol()));
+}
+
+MCSection *
MCObjectFileInfo::getStackSizesSection(const MCSection &TextSec) const {
if ((Ctx->getObjectFileType() != MCContext::IsELF) ||
Ctx->getTargetTriple().isPS4())
diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index e277143..200e29a 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -46,27 +46,83 @@ MCAssembler *MCObjectStreamer::getAssemblerPtr() {
return nullptr;
}
+constexpr size_t FragBlockSize = 16384;
+// Ensure the new fragment can at least store a few bytes.
+constexpr size_t NewFragHeadroom = 8;
+
+static_assert(NewFragHeadroom >= alignof(MCFragment));
+static_assert(FragBlockSize >= sizeof(MCFragment) + NewFragHeadroom);
+
+MCFragment *MCObjectStreamer::allocFragSpace(size_t Headroom) {
+ auto Size = std::max(FragBlockSize, sizeof(MCFragment) + Headroom);
+ FragSpace = Size - sizeof(MCFragment);
+ auto Block = std::unique_ptr<uint8_t[]>(new uint8_t[Size]);
+ auto *F = reinterpret_cast<MCFragment *>(Block.get());
+ FragStorage.push_back(std::move(Block));
+ return F;
+}
+
void MCObjectStreamer::newFragment() {
- addFragment(getContext().allocFragment<MCFragment>());
+ MCFragment *F;
+ if (LLVM_LIKELY(sizeof(MCFragment) + NewFragHeadroom <= FragSpace)) {
+ auto End = reinterpret_cast<size_t>(getCurFragEnd());
+ F = reinterpret_cast<MCFragment *>(
+ alignToPowerOf2(End, alignof(MCFragment)));
+ FragSpace -= size_t(F) - End + sizeof(MCFragment);
+ } else {
+ F = allocFragSpace(0);
+ }
+ new (F) MCFragment();
+ addFragment(F);
+}
+
+void MCObjectStreamer::ensureHeadroom(size_t Headroom) {
+ if (Headroom <= FragSpace)
+ return;
+ auto *F = allocFragSpace(Headroom);
+ new (F) MCFragment();
+ addFragment(F);
}
-void MCObjectStreamer::insert(MCFragment *F) {
- assert(F->getKind() != MCFragment::FT_Data &&
+void MCObjectStreamer::insert(MCFragment *Frag) {
+ assert(Frag->getKind() != MCFragment::FT_Data &&
"F should have a variable-size tail");
+ // Frag is not connected to FragSpace. Before modifying CurFrag with
+ // addFragment(Frag), allocate an empty fragment to maintain FragSpace
+ // connectivity, potentially reusing CurFrag's associated space.
+ MCFragment *F;
+ if (LLVM_LIKELY(sizeof(MCFragment) + NewFragHeadroom <= FragSpace)) {
+ auto End = reinterpret_cast<size_t>(getCurFragEnd());
+ F = reinterpret_cast<MCFragment *>(
+ alignToPowerOf2(End, alignof(MCFragment)));
+ FragSpace -= size_t(F) - End + sizeof(MCFragment);
+ } else {
+ F = allocFragSpace(0);
+ }
+ new (F) MCFragment();
+
+ addFragment(Frag);
addFragment(F);
- newFragment();
}
void MCObjectStreamer::appendContents(ArrayRef<char> Contents) {
- CurFrag->appendContents(Contents);
+ ensureHeadroom(Contents.size());
+ assert(FragSpace >= Contents.size());
+ llvm::copy(Contents, getCurFragEnd());
+ CurFrag->FixedSize += Contents.size();
+ FragSpace -= Contents.size();
}
-void MCObjectStreamer::appendContents(size_t Num, char Elt) {
- CurFrag->appendContents(Num, Elt);
+void MCObjectStreamer::appendContents(size_t Num, uint8_t Elt) {
+ ensureHeadroom(Num);
+ MutableArrayRef<uint8_t> Data(getCurFragEnd(), Num);
+ llvm::fill(Data, Elt);
+ CurFrag->FixedSize += Num;
+ FragSpace -= Num;
}
void MCObjectStreamer::addFixup(const MCExpr *Value, MCFixupKind Kind) {
- CurFrag->addFixup(MCFixup::create(CurFrag->getFixedSize(), Value, Kind));
+ CurFrag->addFixup(MCFixup::create(getCurFragSize(), Value, Kind));
}
// As a compile-time optimization, avoid allocating and evaluating an MCExpr
@@ -115,6 +171,8 @@ void MCObjectStreamer::reset() {
}
EmitEHFrame = true;
EmitDebugFrame = false;
+ FragStorage.clear();
+ FragSpace = 0;
MCStreamer::reset();
}
@@ -143,7 +201,6 @@ void MCObjectStreamer::emitCFISections(bool EH, bool Debug, bool SFrame) {
void MCObjectStreamer::emitValueImpl(const MCExpr *Value, unsigned Size,
SMLoc Loc) {
MCStreamer::emitValueImpl(Value, Size, Loc);
- MCFragment *DF = getCurrentFragment();
MCDwarfLineEntry::make(this, getCurrentSectionOnly());
@@ -158,9 +215,9 @@ void MCObjectStreamer::emitValueImpl(const MCExpr *Value, unsigned Size,
emitIntValue(AbsValue, Size);
return;
}
- DF->addFixup(MCFixup::create(DF->getContents().size(), Value,
- MCFixup::getDataKindForSize(Size)));
- DF->appendContents(Size, 0);
+ ensureHeadroom(Size);
+ addFixup(Value, MCFixup::getDataKindForSize(Size));
+ appendContents(Size, 0);
}
MCSymbol *MCObjectStreamer::emitCFILabel() {
@@ -194,7 +251,7 @@ void MCObjectStreamer::emitLabel(MCSymbol *Symbol, SMLoc Loc) {
// section.
MCFragment *F = CurFrag;
Symbol->setFragment(F);
- Symbol->setOffset(F->getContents().size());
+ Symbol->setOffset(F->getFixedSize());
emitPendingAssignments(Symbol);
}
@@ -260,6 +317,21 @@ void MCObjectStreamer::changeSection(MCSection *Section, uint32_t Subsection) {
F0 = CurFrag;
}
+ // To maintain connectivity between CurFrag and FragSpace when CurFrag is
+ // modified, allocate an empty fragment and append it to the fragment list.
+ // (Subsections[I].second.Tail is not connected to FragSpace.)
+ MCFragment *F;
+ if (LLVM_LIKELY(sizeof(MCFragment) + NewFragHeadroom <= FragSpace)) {
+ auto End = reinterpret_cast<size_t>(getCurFragEnd());
+ F = reinterpret_cast<MCFragment *>(
+ alignToPowerOf2(End, alignof(MCFragment)));
+ FragSpace -= size_t(F) - End + sizeof(MCFragment);
+ } else {
+ F = allocFragSpace(0);
+ }
+ new (F) MCFragment();
+ F->setParent(Section);
+
auto &Subsections = Section->Subsections;
size_t I = 0, E = Subsections.size();
while (I != E && Subsections[I].first < Subsection)
@@ -267,13 +339,16 @@ void MCObjectStreamer::changeSection(MCSection *Section, uint32_t Subsection) {
// If the subsection number is not in the sorted Subsections list, create a
// new fragment list.
if (I == E || Subsections[I].first != Subsection) {
- auto *F = getContext().allocFragment<MCFragment>();
- F->setParent(Section);
Subsections.insert(Subsections.begin() + I,
{Subsection, MCSection::FragList{F, F}});
+ Section->CurFragList = &Subsections[I].second;
+ CurFrag = F;
+ } else {
+ Section->CurFragList = &Subsections[I].second;
+ CurFrag = Subsections[I].second.Tail;
+ // Ensure CurFrag is associated with FragSpace.
+ addFragment(F);
}
- Section->CurFragList = &Subsections[I].second;
- CurFrag = Section->CurFragList->Tail;
// Define the section symbol at subsection 0's initial fragment if required.
if (!NewSec)
@@ -344,11 +419,15 @@ void MCObjectStreamer::emitInstToData(const MCInst &Inst,
MCFragment *F = getCurrentFragment();
// Append the instruction to the data fragment.
- size_t CodeOffset = F->getContents().size();
+ size_t CodeOffset = getCurFragSize();
+ SmallString<16> Content;
SmallVector<MCFixup, 1> Fixups;
- getAssembler().getEmitter().encodeInstruction(
- Inst, F->getContentsForAppending(), Fixups, STI);
- F->doneAppending();
+ getAssembler().getEmitter().encodeInstruction(Inst, Content, Fixups, STI);
+ appendContents(Content);
+ if (CurFrag != F) {
+ F = CurFrag;
+ CodeOffset = 0;
+ }
F->setHasInstructions(STI);
if (Fixups.empty())
diff --git a/llvm/lib/MC/MCSection.cpp b/llvm/lib/MC/MCSection.cpp
index 4f28267..27ca131 100644
--- a/llvm/lib/MC/MCSection.cpp
+++ b/llvm/lib/MC/MCSection.cpp
@@ -83,12 +83,14 @@ void MCFragment::appendFixups(ArrayRef<MCFixup> Fixups) {
}
void MCFragment::setVarFixups(ArrayRef<MCFixup> Fixups) {
+ assert(Fixups.size() < 256 &&
+ "variable-size tail cannot have more than 256 fixups");
auto &S = getParent()->FixupStorage;
- if (VarFixupStart + Fixups.size() > VarFixupEnd) {
+ if (Fixups.size() > VarFixupSize) {
VarFixupStart = S.size();
S.resize_for_overwrite(S.size() + Fixups.size());
}
- VarFixupEnd = VarFixupStart + Fixups.size();
+ VarFixupSize = Fixups.size();
// Source fixup offsets are relative to the variable part's start. Add the
// fixed part size to make them relative to the fixed part's start.
std::transform(Fixups.begin(), Fixups.end(), S.begin() + VarFixupStart,
diff --git a/llvm/lib/MC/MCWin64EH.cpp b/llvm/lib/MC/MCWin64EH.cpp
index 72a8dd7..a87648a 100644
--- a/llvm/lib/MC/MCWin64EH.cpp
+++ b/llvm/lib/MC/MCWin64EH.cpp
@@ -318,6 +318,9 @@ static void EmitUnwindInfo(MCStreamer &streamer, WinEH::FrameInfo *info) {
// Emit the epilog instructions.
if (EnableUnwindV2) {
+ // Ensure the fixups and appended content apply to the same fragment.
+ OS->ensureHeadroom(info->EpilogMap.size() * 2);
+
bool IsLast = true;
for (const auto &Epilog : llvm::reverse(info->EpilogMap)) {
if (IsLast) {
diff --git a/llvm/lib/MC/MCWinCOFFStreamer.cpp b/llvm/lib/MC/MCWinCOFFStreamer.cpp
index 1ffe25c..8be5054 100644
--- a/llvm/lib/MC/MCWinCOFFStreamer.cpp
+++ b/llvm/lib/MC/MCWinCOFFStreamer.cpp
@@ -280,6 +280,7 @@ void MCWinCOFFStreamer::emitCOFFSymbolIndex(MCSymbol const *Symbol) {
void MCWinCOFFStreamer::emitCOFFSectionIndex(const MCSymbol *Symbol) {
visitUsedSymbol(*Symbol);
const MCSymbolRefExpr *SRE = MCSymbolRefExpr::create(Symbol, getContext());
+ ensureHeadroom(2);
addFixup(SRE, FK_SecRel_2);
appendContents(2, 0);
}
@@ -293,6 +294,7 @@ void MCWinCOFFStreamer::emitCOFFSecRel32(const MCSymbol *Symbol,
if (Offset)
MCE = MCBinaryExpr::createAdd(
MCE, MCConstantExpr::create(Offset, getContext()), getContext());
+ ensureHeadroom(4);
addFixup(MCE, FK_SecRel_4);
// Emit 4 bytes (zeros) to the object file.
appendContents(4, 0);
@@ -308,6 +310,7 @@ void MCWinCOFFStreamer::emitCOFFImgRel32(const MCSymbol *Symbol,
if (Offset)
MCE = MCBinaryExpr::createAdd(
MCE, MCConstantExpr::create(Offset, getContext()), getContext());
+ ensureHeadroom(4);
addFixup(MCE, FK_Data_4);
// Emit 4 bytes (zeros) to the object file.
appendContents(4, 0);
@@ -318,6 +321,7 @@ void MCWinCOFFStreamer::emitCOFFSecNumber(MCSymbol const *Symbol) {
// Create Symbol for section number.
const MCExpr *MCE = MCCOFFSectionNumberTargetExpr::create(
*Symbol, this->getWriter(), getContext());
+ ensureHeadroom(4);
addFixup(MCE, FK_Data_4);
// Emit 4 bytes (zeros) to the object file.
appendContents(4, 0);
@@ -328,6 +332,7 @@ void MCWinCOFFStreamer::emitCOFFSecOffset(MCSymbol const *Symbol) {
// Create Symbol for section offset.
const MCExpr *MCE =
MCCOFFSectionOffsetTargetExpr::create(*Symbol, getContext());
+ ensureHeadroom(4);
addFixup(MCE, FK_Data_4);
// Emit 4 bytes (zeros) to the object file.
appendContents(4, 0);
diff --git a/llvm/lib/MC/MCXCOFFStreamer.cpp b/llvm/lib/MC/MCXCOFFStreamer.cpp
index 898ac5d..26f45ce 100644
--- a/llvm/lib/MC/MCXCOFFStreamer.cpp
+++ b/llvm/lib/MC/MCXCOFFStreamer.cpp
@@ -103,16 +103,8 @@ void MCXCOFFStreamer::emitXCOFFSymbolLinkageWithVisibility(
void MCXCOFFStreamer::emitXCOFFRefDirective(const MCSymbol *Symbol) {
// Add a Fixup here to later record a relocation of type R_REF to prevent the
// ref symbol from being garbage collected (by the binder).
- MCFragment *DF = getCurrentFragment();
- const MCSymbolRefExpr *SRE = MCSymbolRefExpr::create(Symbol, getContext());
- std::optional<MCFixupKind> MaybeKind =
- getAssembler().getBackend().getFixupKind("R_REF");
- if (!MaybeKind)
- report_fatal_error("failed to get fixup kind for R_REF relocation");
-
- MCFixupKind Kind = *MaybeKind;
- MCFixup Fixup = MCFixup::create(DF->getContents().size(), SRE, Kind);
- DF->addFixup(Fixup);
+ addFixup(MCSymbolRefExpr::create(Symbol, getContext()),
+ XCOFF::RelocationType::R_REF);
}
void MCXCOFFStreamer::emitXCOFFRenameDirective(const MCSymbol *Name,
generated by cgit v1.1 at 2025-08-03 16:24:37 +0000