MC: Refactor FT_Align fragments when linker relaxation is enabled #149465
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Created using spr 1.3.5-bogner [skip ci]
Created using spr 1.3.5-bogner
|
@llvm/pr-subscribers-mc @llvm/pr-subscribers-backend-risc-v Author: Fangrui Song (MaskRay) ChangesPreviously, two MCAsmBackend hooks were used, with This patch:
Patch is 23.35 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/149465.diff 10 Files Affected:
diff --git a/llvm/include/llvm/MC/MCAsmBackend.h b/llvm/include/llvm/MC/MCAsmBackend.h
index 93259b0ea6d74..e476b76e0ab08 100644
--- a/llvm/include/llvm/MC/MCAsmBackend.h
+++ b/llvm/include/llvm/MC/MCAsmBackend.h
@@ -103,20 +103,6 @@ class LLVM_ABI MCAsmBackend {
/// Get information on a fixup kind.
virtual MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const;
- /// Hook to check if extra nop bytes must be inserted for alignment directive.
- /// For some targets this may be necessary in order to support linker
- /// relaxation. The number of bytes to insert are returned in Size.
- virtual bool shouldInsertExtraNopBytesForCodeAlign(const MCFragment &AF,
- unsigned &Size) {
- return false;
- }
-
- /// Hook which indicates if the target requires a fixup to be generated when
- /// handling an align directive in an executable section
- virtual bool shouldInsertFixupForCodeAlign(MCAssembler &Asm, MCFragment &AF) {
- return false;
- }
-
// Evaluate a fixup, returning std::nullopt to use default handling for
// `Value` and `IsResolved`. Otherwise, returns `IsResolved` with the
// expectation that the hook updates `Value`.
@@ -174,6 +160,10 @@ class LLVM_ABI MCAsmBackend {
}
// Defined by linker relaxation targets.
+
+ // Return false to use default handling. Otherwise, set `Size` to the number
+ // of padding bytes.
+ virtual bool relaxAlign(MCFragment &F, unsigned &Size) { return false; }
virtual bool relaxDwarfLineAddr(MCFragment &, bool &WasRelaxed) const {
return false;
}
diff --git a/llvm/lib/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp
index f18ca38a27cad..cc6817fc62a24 100644
--- a/llvm/lib/MC/MCAssembler.cpp
+++ b/llvm/lib/MC/MCAssembler.cpp
@@ -230,22 +230,24 @@ uint64_t MCAssembler::computeFragmentSize(const MCFragment &F) const {
case MCFragment::FT_Align: {
unsigned Offset = F.Offset + F.getFixedSize();
unsigned Size = offsetToAlignment(Offset, F.getAlignment());
-
- // Insert extra Nops for code alignment if the target define
- // shouldInsertExtraNopBytesForCodeAlign target hook.
- if (F.getParent()->useCodeAlign() && F.hasAlignEmitNops() &&
- getBackend().shouldInsertExtraNopBytesForCodeAlign(F, Size))
- return F.getFixedSize() + Size;
-
- // If we are padding with nops, force the padding to be larger than the
- // minimum nop size.
- if (Size > 0 && F.hasAlignEmitNops()) {
- while (Size % getBackend().getMinimumNopSize())
- Size += F.getAlignment().value();
+ auto &Frag = const_cast<MCFragment &>(F);
+ // In the nops mode, RISC-V style linker relaxation might adjust the size
+ // and add a fixup, even if `Size` is originally 0.
+ bool AlignFixup = false;
+ if (F.hasAlignEmitNops()) {
+ AlignFixup = getBackend().relaxAlign(Frag, Size);
+ // If the backend does not handle the fragment specially, pad with nops,
+ // but ensure that the padding is larger than the minimum nop size.
+ if (!AlignFixup)
+ while (Size % getBackend().getMinimumNopSize())
+ Size += F.getAlignment().value();
}
- if (Size > F.getAlignMaxBytesToEmit())
+ if (!AlignFixup && Size > F.getAlignMaxBytesToEmit())
Size = 0;
- return F.getFixedSize() + Size;
+ Frag.VarContentEnd = F.VarContentStart + Size;
+ if (Frag.VarContentEnd > Frag.getParent()->ContentStorage.size())
+ Frag.getParent()->ContentStorage.resize(Frag.VarContentEnd);
+ return F.getSize();
}
case MCFragment::FT_Org: {
@@ -419,7 +421,6 @@ static void writeFragment(raw_ostream &OS, const MCAssembler &Asm,
switch (F.getKind()) {
case MCFragment::FT_Data:
case MCFragment::FT_Relaxable:
- case MCFragment::FT_Align:
case MCFragment::FT_LEB:
case MCFragment::FT_Dwarf:
case MCFragment::FT_DwarfFrame:
@@ -433,42 +434,44 @@ static void writeFragment(raw_ostream &OS, const MCAssembler &Asm,
const auto &EF = cast<MCFragment>(F);
OS << StringRef(EF.getContents().data(), EF.getContents().size());
OS << StringRef(EF.getVarContents().data(), EF.getVarContents().size());
- if (F.getKind() == MCFragment::FT_Align) {
- ++stats::EmittedAlignFragments;
- assert(F.getAlignFillLen() &&
- "Invalid virtual align in concrete fragment!");
-
- uint64_t Count = (FragmentSize - F.getFixedSize()) / F.getAlignFillLen();
- assert((FragmentSize - F.getFixedSize()) % F.getAlignFillLen() == 0 &&
- "computeFragmentSize computed size is incorrect");
-
- // See if we are aligning with nops, and if so do that first to try to
- // fill the Count bytes. Then if that did not fill any bytes or there are
- // any bytes left to fill use the Value and ValueSize to fill the rest. If
- // we are aligning with nops, ask that target to emit the right data.
- if (F.hasAlignEmitNops()) {
- if (!Asm.getBackend().writeNopData(OS, Count, F.getSubtargetInfo()))
- report_fatal_error("unable to write nop sequence of " + Twine(Count) +
- " bytes");
- } else {
- // Otherwise, write out in multiples of the value size.
- for (uint64_t i = 0; i != Count; ++i) {
- switch (F.getAlignFillLen()) {
- default:
- llvm_unreachable("Invalid size!");
- case 1:
- OS << char(F.getAlignFill());
- break;
- case 2:
- support::endian::write<uint16_t>(OS, F.getAlignFill(), Endian);
- break;
- case 4:
- support::endian::write<uint32_t>(OS, F.getAlignFill(), Endian);
- break;
- case 8:
- support::endian::write<uint64_t>(OS, F.getAlignFill(), Endian);
- break;
- }
+ } break;
+
+ case MCFragment::FT_Align: {
+ ++stats::EmittedAlignFragments;
+ OS << StringRef(F.getContents().data(), F.getContents().size());
+ assert(F.getAlignFillLen() &&
+ "Invalid virtual align in concrete fragment!");
+
+ uint64_t Count = (FragmentSize - F.getFixedSize()) / F.getAlignFillLen();
+ assert((FragmentSize - F.getFixedSize()) % F.getAlignFillLen() == 0 &&
+ "computeFragmentSize computed size is incorrect");
+
+ // See if we are aligning with nops, and if so do that first to try to
+ // fill the Count bytes. Then if that did not fill any bytes or there are
+ // any bytes left to fill use the Value and ValueSize to fill the rest. If
+ // we are aligning with nops, ask that target to emit the right data.
+ if (F.hasAlignEmitNops()) {
+ if (!Asm.getBackend().writeNopData(OS, Count, F.getSubtargetInfo()))
+ report_fatal_error("unable to write nop sequence of " + Twine(Count) +
+ " bytes");
+ } else {
+ // Otherwise, write out in multiples of the value size.
+ for (uint64_t i = 0; i != Count; ++i) {
+ switch (F.getAlignFillLen()) {
+ default:
+ llvm_unreachable("Invalid size!");
+ case 1:
+ OS << char(F.getAlignFill());
+ break;
+ case 2:
+ support::endian::write<uint16_t>(OS, F.getAlignFill(), Endian);
+ break;
+ case 4:
+ support::endian::write<uint32_t>(OS, F.getAlignFill(), Endian);
+ break;
+ case 8:
+ support::endian::write<uint64_t>(OS, F.getAlignFill(), Endian);
+ break;
}
}
}
@@ -739,11 +742,6 @@ void MCAssembler::layout() {
evaluateFixup(F, Fixup, Target, FixedValue,
/*RecordReloc=*/true, Contents);
}
- } else if (F.getKind() == MCFragment::FT_Align) {
- // For RISC-V linker relaxation, an alignment relocation might be
- // needed.
- if (F.hasAlignEmitNops())
- getBackend().shouldInsertFixupForCodeAlign(*this, F);
}
}
}
diff --git a/llvm/lib/MC/MCExpr.cpp b/llvm/lib/MC/MCExpr.cpp
index f0f1bd485258f..dbb2fd16eb2e5 100644
--- a/llvm/lib/MC/MCExpr.cpp
+++ b/llvm/lib/MC/MCExpr.cpp
@@ -370,7 +370,6 @@ static void attemptToFoldSymbolOffsetDifference(const MCAssembler *Asm,
}
int64_t Num;
- unsigned Count;
if (DF) {
Displacement += DF->getContents().size();
} else if (F->getKind() == MCFragment::FT_Relaxable &&
@@ -380,9 +379,7 @@ static void attemptToFoldSymbolOffsetDifference(const MCAssembler *Asm,
// data fragment.
Displacement += F->getSize();
} else if (F->getKind() == MCFragment::FT_Align && Layout &&
- F->hasAlignEmitNops() &&
- !Asm->getBackend().shouldInsertExtraNopBytesForCodeAlign(
- *F, Count)) {
+ F->isLinkerRelaxable()) {
Displacement += Asm->computeFragmentSize(*F);
} else if (auto *FF = dyn_cast<MCFillFragment>(F);
FF && FF->getNumValues().evaluateAsAbsolute(Num)) {
diff --git a/llvm/lib/MC/MCFragment.cpp b/llvm/lib/MC/MCFragment.cpp
index d01660f640c46..bfaeb2be1ec90 100644
--- a/llvm/lib/MC/MCFragment.cpp
+++ b/llvm/lib/MC/MCFragment.cpp
@@ -84,8 +84,13 @@ LLVM_DUMP_METHOD void MCFragment::dump() const {
auto Fixed = getContents();
auto Var = getVarContents();
OS << " Size:" << Fixed.size();
- if (getKind() != MCFragment::FT_Data)
+ if (getKind() != MCFragment::FT_Data) {
OS << '+' << Var.size();
+ // FT_Align uses getVarContents to track the size, but the content is
+ // garbage and not useful.
+ if (getKind() == MCFragment::FT_Align)
+ Var = {};
+ }
OS << " [";
for (unsigned i = 0, e = Fixed.size(); i != e; ++i) {
if (i) OS << ",";
diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index 6ac598b4d0d3b..99f8dd93efd9e 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -564,12 +564,6 @@ void MCObjectStreamer::emitCodeAlignment(Align Alignment,
emitValueToAlignment(Alignment, 0, 1, MaxBytesToEmit);
auto *F = getCurrentFragment();
F->setAlignEmitNops(true, STI);
- // With RISC-V style linker relaxation, mark the section as linker-relaxable
- // if the alignment is larger than the minimum NOP size.
- unsigned Size;
- if (getAssembler().getBackend().shouldInsertExtraNopBytesForCodeAlign(*F,
- Size))
- getCurrentSectionOnly()->setLinkerRelaxable();
}
void MCObjectStreamer::emitValueToOffset(const MCExpr *Offset,
diff --git a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp
index 032bfea71140f..b1cf001c4bdca 100644
--- a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp
+++ b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp
@@ -177,74 +177,6 @@ void LoongArchAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
}
}
-// Linker relaxation may change code size. We have to insert Nops
-// for .align directive when linker relaxation enabled. So then Linker
-// could satisfy alignment by removing Nops.
-// The function returns the total Nops Size we need to insert.
-bool LoongArchAsmBackend::shouldInsertExtraNopBytesForCodeAlign(
- const MCFragment &AF, unsigned &Size) {
- // Calculate Nops Size only when linker relaxation enabled.
- if (!AF.getSubtargetInfo()->hasFeature(LoongArch::FeatureRelax))
- return false;
-
- // Ignore alignment if MaxBytesToEmit is less than the minimum Nop size.
- const unsigned MinNopLen = 4;
- if (AF.getAlignMaxBytesToEmit() < MinNopLen)
- return false;
- Size = AF.getAlignment().value() - MinNopLen;
- return AF.getAlignment() > MinNopLen;
-}
-
-// We need to insert R_LARCH_ALIGN relocation type to indicate the
-// position of Nops and the total bytes of the Nops have been inserted
-// when linker relaxation enabled.
-// The function inserts fixup_loongarch_align fixup which eventually will
-// transfer to R_LARCH_ALIGN relocation type.
-// The improved R_LARCH_ALIGN requires symbol index. The lowest 8 bits of
-// addend represent alignment and the other bits of addend represent the
-// maximum number of bytes to emit. The maximum number of bytes is zero
-// means ignore the emit limit.
-bool LoongArchAsmBackend::shouldInsertFixupForCodeAlign(MCAssembler &Asm,
- MCFragment &AF) {
- // Insert the fixup only when linker relaxation enabled.
- if (!AF.getSubtargetInfo()->hasFeature(LoongArch::FeatureRelax))
- return false;
-
- // Calculate total Nops we need to insert. If there are none to insert
- // then simply return.
- unsigned InsertedNopBytes;
- if (!shouldInsertExtraNopBytesForCodeAlign(AF, InsertedNopBytes))
- return false;
-
- MCSection *Sec = AF.getParent();
- MCContext &Ctx = getContext();
- const MCExpr *Dummy = MCConstantExpr::create(0, Ctx);
- MCFixup Fixup = MCFixup::create(AF.getFixedSize(), Dummy, ELF::R_LARCH_ALIGN);
- unsigned MaxBytesToEmit = AF.getAlignMaxBytesToEmit();
-
- auto createExtendedValue = [&]() {
- const MCSymbolRefExpr *MCSym = getSecToAlignSym()[Sec];
- if (MCSym == nullptr) {
- // Define a marker symbol at the section with an offset of 0.
- MCSymbol *Sym = Ctx.createNamedTempSymbol("la-relax-align");
- Sym->setFragment(&*Sec->getBeginSymbol()->getFragment());
- Asm.registerSymbol(*Sym);
- MCSym = MCSymbolRefExpr::create(Sym, Ctx);
- getSecToAlignSym()[Sec] = MCSym;
- }
- return MCValue::get(&MCSym->getSymbol(), nullptr,
- MaxBytesToEmit << 8 | Log2(AF.getAlignment()));
- };
-
- uint64_t FixedValue = 0;
- MCValue Value = MaxBytesToEmit >= InsertedNopBytes
- ? MCValue::get(InsertedNopBytes)
- : createExtendedValue();
- Asm.getWriter().recordRelocation(AF, Fixup, Value, FixedValue);
-
- return true;
-}
-
bool LoongArchAsmBackend::shouldForceRelocation(const MCFixup &Fixup,
const MCValue &Target) {
switch (Fixup.getKind()) {
@@ -279,6 +211,61 @@ getRelocPairForSize(unsigned Size) {
}
}
+// Linker relaxation may change code size. We have to insert Nops
+// for .align directive when linker relaxation enabled. So then Linker
+// could satisfy alignment by removing Nops.
+// The function returns the total Nops Size we need to insert.
+bool LoongArchAsmBackend::relaxAlign(MCFragment &F, unsigned &Size) {
+ // Use default handling unless linker relaxation is enabled and the
+ // MaxBytesToEmit >= the nop size.
+ if (!F.getSubtargetInfo()->hasFeature(LoongArch::FeatureRelax))
+ return false;
+ const unsigned MinNopLen = 4;
+ unsigned MaxBytesToEmit = F.getAlignMaxBytesToEmit();
+ if (MaxBytesToEmit < MinNopLen)
+ return false;
+
+ Size = F.getAlignment().value() - MinNopLen;
+ if (F.getAlignment() <= MinNopLen)
+ return false;
+
+ // We need to insert R_LARCH_ALIGN relocation type to indicate the
+ // position of Nops and the total bytes of the Nops have been inserted
+ // when linker relaxation enabled.
+ // The function inserts fixup_loongarch_align fixup which eventually will
+ // transfer to R_LARCH_ALIGN relocation type.
+ // The improved R_LARCH_ALIGN requires symbol index. The lowest 8 bits of
+ // addend represent alignment and the other bits of addend represent the
+ // maximum number of bytes to emit. The maximum number of bytes is zero
+ // means ignore the emit limit.
+ MCContext &Ctx = getContext();
+ const MCExpr *Expr = nullptr;
+ if (MaxBytesToEmit >= Size) {
+ Expr = MCConstantExpr::create(Size, getContext());
+ } else {
+ MCSection *Sec = F.getParent();
+ const MCSymbolRefExpr *SymRef = getSecToAlignSym()[Sec];
+ if (SymRef == nullptr) {
+ // Define a marker symbol at the section with an offset of 0.
+ MCSymbol *Sym = Ctx.createNamedTempSymbol("la-relax-align");
+ Sym->setFragment(&*Sec->getBeginSymbol()->getFragment());
+ Asm->registerSymbol(*Sym);
+ SymRef = MCSymbolRefExpr::create(Sym, Ctx);
+ getSecToAlignSym()[Sec] = SymRef;
+ }
+ Expr = MCBinaryExpr::createAdd(
+ SymRef,
+ MCConstantExpr::create((MaxBytesToEmit << 8) | Log2(F.getAlignment()),
+ Ctx),
+ Ctx);
+ }
+ MCFixup Fixup =
+ MCFixup::create(0, Expr, FirstLiteralRelocationKind + ELF::R_LARCH_ALIGN);
+ F.setVarFixups({Fixup});
+ F.getParent()->setLinkerRelaxable();
+ return true;
+}
+
std::pair<bool, bool> LoongArchAsmBackend::relaxLEB128(MCFragment &F,
int64_t &Value) const {
const MCExpr &Expr = F.getLEBValue();
diff --git a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h
index 793e4093b1c9e..3d929fc49f95e 100644
--- a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h
+++ b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h
@@ -45,19 +45,13 @@ class LoongArchAsmBackend : public MCAsmBackend {
MutableArrayRef<char> Data, uint64_t Value,
bool IsResolved) override;
- // Return Size with extra Nop Bytes for alignment directive in code section.
- bool shouldInsertExtraNopBytesForCodeAlign(const MCFragment &AF,
- unsigned &Size) override;
-
- // Insert target specific fixup type for alignment directive in code section.
- bool shouldInsertFixupForCodeAlign(MCAssembler &Asm, MCFragment &AF) override;
-
bool shouldForceRelocation(const MCFixup &Fixup, const MCValue &Target);
std::optional<MCFixupKind> getFixupKind(StringRef Name) const override;
MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override;
+ bool relaxAlign(MCFragment &F, unsigned &Size) override;
bool relaxDwarfLineAddr(MCFragment &F, bool &WasRelaxed) const override;
bool relaxDwarfCFA(MCFragment &F, bool &WasRelaxed) const override;
std::pair<bool, bool> relaxLEB128(MCFragment &F,
diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
index 6bc313656f7c1..3d124bace92fe 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
@@ -302,6 +302,25 @@ void RISCVAsmBackend::relaxInstruction(MCInst &Inst,
Inst = std::move(Res);
}
+bool RISCVAsmBackend::relaxAlign(MCFragment &F, unsigned &Size) {
+ // Use default handling unless linker relaxation is enabled and the alignment
+ // is larger than the nop size.
+ const MCSubtargetInfo *STI = F.getSubtargetInfo();
+ if (!STI->hasFeature(RISCV::FeatureRelax))
+ return false;
+ unsigned MinNopLen = STI->hasFeature(RISCV::FeatureStdExtZca) ? 2 : 4;
+ if (F.getAlignment() <= MinNopLen)
+ return false;
+
+ Size = F.getAlignment().value() - MinNopLen;
+ auto *Expr = MCConstantExpr::create(Size, getContext());
+ MCFixup Fixup =
+ MCFixup::create(0, Expr, FirstLiteralRelocationKind + ELF::R_RISCV_ALIGN);
+ F.setVarFixups({Fixup});
+ F.getParent()->setLinkerRelaxable();
+ return true;
+}
+
bool RISCVAsmBackend::relaxDwarfLineAddr(MCFragment &F,
bool &WasRelaxed) const {
MCContext &C = getContext();
@@ -887,55 +906,6 @@ void RISCVAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
}
}
-// Linker relaxation may change code size. We have to insert Nops
-// for .align directive when linker relaxation enabled. So then Linker
-// could satisfy alignment by removing Nops.
-// The function return the total Nops Size we need to insert.
-bool RISCVAsmBackend::shouldInsertExtraNopBytesForCodeAlign(
- const MCFragment &AF, unsigned &Size) {
- // Calculate Nops Size only when linker relaxation enabled.
- const MCSubtargetInfo *STI = AF.getSubtargetInfo();
- if (!STI->hasFeature(RISCV::FeatureRelax))
- return false;
-
- unsigned MinNopLen = STI->hasFeature(RISCV::FeatureStdExtZca) ? 2 : 4;
-
- if (AF.getAlignment() <= MinNopLen) {
- return false;
- } else {
- Size = AF.getAlignment().value() - MinNopLen;
- return true;
- }
-}
-
-// We need to insert R_RISCV_ALIGN relocation type to indicate the
-// position of Nops and the total bytes of the Nops have been inserted
-// when linker relaxation en...
[truncated]
|
|
@llvm/pr-subscribers-backend-loongarch Author: Fangrui Song (MaskRay) ChangesPreviously, two MCAsmBackend hooks were used, with This patch:
Patch is 23.35 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/149465.diff 10 Files Affected:
diff --git a/llvm/include/llvm/MC/MCAsmBackend.h b/llvm/include/llvm/MC/MCAsmBackend.h
index 93259b0ea6d74..e476b76e0ab08 100644
--- a/llvm/include/llvm/MC/MCAsmBackend.h
+++ b/llvm/include/llvm/MC/MCAsmBackend.h
@@ -103,20 +103,6 @@ class LLVM_ABI MCAsmBackend {
/// Get information on a fixup kind.
virtual MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const;
- /// Hook to check if extra nop bytes must be inserted for alignment directive.
- /// For some targets this may be necessary in order to support linker
- /// relaxation. The number of bytes to insert are returned in Size.
- virtual bool shouldInsertExtraNopBytesForCodeAlign(const MCFragment &AF,
- unsigned &Size) {
- return false;
- }
-
- /// Hook which indicates if the target requires a fixup to be generated when
- /// handling an align directive in an executable section
- virtual bool shouldInsertFixupForCodeAlign(MCAssembler &Asm, MCFragment &AF) {
- return false;
- }
-
// Evaluate a fixup, returning std::nullopt to use default handling for
// `Value` and `IsResolved`. Otherwise, returns `IsResolved` with the
// expectation that the hook updates `Value`.
@@ -174,6 +160,10 @@ class LLVM_ABI MCAsmBackend {
}
// Defined by linker relaxation targets.
+
+ // Return false to use default handling. Otherwise, set `Size` to the number
+ // of padding bytes.
+ virtual bool relaxAlign(MCFragment &F, unsigned &Size) { return false; }
virtual bool relaxDwarfLineAddr(MCFragment &, bool &WasRelaxed) const {
return false;
}
diff --git a/llvm/lib/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp
index f18ca38a27cad..cc6817fc62a24 100644
--- a/llvm/lib/MC/MCAssembler.cpp
+++ b/llvm/lib/MC/MCAssembler.cpp
@@ -230,22 +230,24 @@ uint64_t MCAssembler::computeFragmentSize(const MCFragment &F) const {
case MCFragment::FT_Align: {
unsigned Offset = F.Offset + F.getFixedSize();
unsigned Size = offsetToAlignment(Offset, F.getAlignment());
-
- // Insert extra Nops for code alignment if the target define
- // shouldInsertExtraNopBytesForCodeAlign target hook.
- if (F.getParent()->useCodeAlign() && F.hasAlignEmitNops() &&
- getBackend().shouldInsertExtraNopBytesForCodeAlign(F, Size))
- return F.getFixedSize() + Size;
-
- // If we are padding with nops, force the padding to be larger than the
- // minimum nop size.
- if (Size > 0 && F.hasAlignEmitNops()) {
- while (Size % getBackend().getMinimumNopSize())
- Size += F.getAlignment().value();
+ auto &Frag = const_cast<MCFragment &>(F);
+ // In the nops mode, RISC-V style linker relaxation might adjust the size
+ // and add a fixup, even if `Size` is originally 0.
+ bool AlignFixup = false;
+ if (F.hasAlignEmitNops()) {
+ AlignFixup = getBackend().relaxAlign(Frag, Size);
+ // If the backend does not handle the fragment specially, pad with nops,
+ // but ensure that the padding is larger than the minimum nop size.
+ if (!AlignFixup)
+ while (Size % getBackend().getMinimumNopSize())
+ Size += F.getAlignment().value();
}
- if (Size > F.getAlignMaxBytesToEmit())
+ if (!AlignFixup && Size > F.getAlignMaxBytesToEmit())
Size = 0;
- return F.getFixedSize() + Size;
+ Frag.VarContentEnd = F.VarContentStart + Size;
+ if (Frag.VarContentEnd > Frag.getParent()->ContentStorage.size())
+ Frag.getParent()->ContentStorage.resize(Frag.VarContentEnd);
+ return F.getSize();
}
case MCFragment::FT_Org: {
@@ -419,7 +421,6 @@ static void writeFragment(raw_ostream &OS, const MCAssembler &Asm,
switch (F.getKind()) {
case MCFragment::FT_Data:
case MCFragment::FT_Relaxable:
- case MCFragment::FT_Align:
case MCFragment::FT_LEB:
case MCFragment::FT_Dwarf:
case MCFragment::FT_DwarfFrame:
@@ -433,42 +434,44 @@ static void writeFragment(raw_ostream &OS, const MCAssembler &Asm,
const auto &EF = cast<MCFragment>(F);
OS << StringRef(EF.getContents().data(), EF.getContents().size());
OS << StringRef(EF.getVarContents().data(), EF.getVarContents().size());
- if (F.getKind() == MCFragment::FT_Align) {
- ++stats::EmittedAlignFragments;
- assert(F.getAlignFillLen() &&
- "Invalid virtual align in concrete fragment!");
-
- uint64_t Count = (FragmentSize - F.getFixedSize()) / F.getAlignFillLen();
- assert((FragmentSize - F.getFixedSize()) % F.getAlignFillLen() == 0 &&
- "computeFragmentSize computed size is incorrect");
-
- // See if we are aligning with nops, and if so do that first to try to
- // fill the Count bytes. Then if that did not fill any bytes or there are
- // any bytes left to fill use the Value and ValueSize to fill the rest. If
- // we are aligning with nops, ask that target to emit the right data.
- if (F.hasAlignEmitNops()) {
- if (!Asm.getBackend().writeNopData(OS, Count, F.getSubtargetInfo()))
- report_fatal_error("unable to write nop sequence of " + Twine(Count) +
- " bytes");
- } else {
- // Otherwise, write out in multiples of the value size.
- for (uint64_t i = 0; i != Count; ++i) {
- switch (F.getAlignFillLen()) {
- default:
- llvm_unreachable("Invalid size!");
- case 1:
- OS << char(F.getAlignFill());
- break;
- case 2:
- support::endian::write<uint16_t>(OS, F.getAlignFill(), Endian);
- break;
- case 4:
- support::endian::write<uint32_t>(OS, F.getAlignFill(), Endian);
- break;
- case 8:
- support::endian::write<uint64_t>(OS, F.getAlignFill(), Endian);
- break;
- }
+ } break;
+
+ case MCFragment::FT_Align: {
+ ++stats::EmittedAlignFragments;
+ OS << StringRef(F.getContents().data(), F.getContents().size());
+ assert(F.getAlignFillLen() &&
+ "Invalid virtual align in concrete fragment!");
+
+ uint64_t Count = (FragmentSize - F.getFixedSize()) / F.getAlignFillLen();
+ assert((FragmentSize - F.getFixedSize()) % F.getAlignFillLen() == 0 &&
+ "computeFragmentSize computed size is incorrect");
+
+ // See if we are aligning with nops, and if so do that first to try to
+ // fill the Count bytes. Then if that did not fill any bytes or there are
+ // any bytes left to fill use the Value and ValueSize to fill the rest. If
+ // we are aligning with nops, ask that target to emit the right data.
+ if (F.hasAlignEmitNops()) {
+ if (!Asm.getBackend().writeNopData(OS, Count, F.getSubtargetInfo()))
+ report_fatal_error("unable to write nop sequence of " + Twine(Count) +
+ " bytes");
+ } else {
+ // Otherwise, write out in multiples of the value size.
+ for (uint64_t i = 0; i != Count; ++i) {
+ switch (F.getAlignFillLen()) {
+ default:
+ llvm_unreachable("Invalid size!");
+ case 1:
+ OS << char(F.getAlignFill());
+ break;
+ case 2:
+ support::endian::write<uint16_t>(OS, F.getAlignFill(), Endian);
+ break;
+ case 4:
+ support::endian::write<uint32_t>(OS, F.getAlignFill(), Endian);
+ break;
+ case 8:
+ support::endian::write<uint64_t>(OS, F.getAlignFill(), Endian);
+ break;
}
}
}
@@ -739,11 +742,6 @@ void MCAssembler::layout() {
evaluateFixup(F, Fixup, Target, FixedValue,
/*RecordReloc=*/true, Contents);
}
- } else if (F.getKind() == MCFragment::FT_Align) {
- // For RISC-V linker relaxation, an alignment relocation might be
- // needed.
- if (F.hasAlignEmitNops())
- getBackend().shouldInsertFixupForCodeAlign(*this, F);
}
}
}
diff --git a/llvm/lib/MC/MCExpr.cpp b/llvm/lib/MC/MCExpr.cpp
index f0f1bd485258f..dbb2fd16eb2e5 100644
--- a/llvm/lib/MC/MCExpr.cpp
+++ b/llvm/lib/MC/MCExpr.cpp
@@ -370,7 +370,6 @@ static void attemptToFoldSymbolOffsetDifference(const MCAssembler *Asm,
}
int64_t Num;
- unsigned Count;
if (DF) {
Displacement += DF->getContents().size();
} else if (F->getKind() == MCFragment::FT_Relaxable &&
@@ -380,9 +379,7 @@ static void attemptToFoldSymbolOffsetDifference(const MCAssembler *Asm,
// data fragment.
Displacement += F->getSize();
} else if (F->getKind() == MCFragment::FT_Align && Layout &&
- F->hasAlignEmitNops() &&
- !Asm->getBackend().shouldInsertExtraNopBytesForCodeAlign(
- *F, Count)) {
+ F->isLinkerRelaxable()) {
Displacement += Asm->computeFragmentSize(*F);
} else if (auto *FF = dyn_cast<MCFillFragment>(F);
FF && FF->getNumValues().evaluateAsAbsolute(Num)) {
diff --git a/llvm/lib/MC/MCFragment.cpp b/llvm/lib/MC/MCFragment.cpp
index d01660f640c46..bfaeb2be1ec90 100644
--- a/llvm/lib/MC/MCFragment.cpp
+++ b/llvm/lib/MC/MCFragment.cpp
@@ -84,8 +84,13 @@ LLVM_DUMP_METHOD void MCFragment::dump() const {
auto Fixed = getContents();
auto Var = getVarContents();
OS << " Size:" << Fixed.size();
- if (getKind() != MCFragment::FT_Data)
+ if (getKind() != MCFragment::FT_Data) {
OS << '+' << Var.size();
+ // FT_Align uses getVarContents to track the size, but the content is
+ // garbage and not useful.
+ if (getKind() == MCFragment::FT_Align)
+ Var = {};
+ }
OS << " [";
for (unsigned i = 0, e = Fixed.size(); i != e; ++i) {
if (i) OS << ",";
diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index 6ac598b4d0d3b..99f8dd93efd9e 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -564,12 +564,6 @@ void MCObjectStreamer::emitCodeAlignment(Align Alignment,
emitValueToAlignment(Alignment, 0, 1, MaxBytesToEmit);
auto *F = getCurrentFragment();
F->setAlignEmitNops(true, STI);
- // With RISC-V style linker relaxation, mark the section as linker-relaxable
- // if the alignment is larger than the minimum NOP size.
- unsigned Size;
- if (getAssembler().getBackend().shouldInsertExtraNopBytesForCodeAlign(*F,
- Size))
- getCurrentSectionOnly()->setLinkerRelaxable();
}
void MCObjectStreamer::emitValueToOffset(const MCExpr *Offset,
diff --git a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp
index 032bfea71140f..b1cf001c4bdca 100644
--- a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp
+++ b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.cpp
@@ -177,74 +177,6 @@ void LoongArchAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
}
}
-// Linker relaxation may change code size. We have to insert Nops
-// for .align directive when linker relaxation enabled. So then Linker
-// could satisfy alignment by removing Nops.
-// The function returns the total Nops Size we need to insert.
-bool LoongArchAsmBackend::shouldInsertExtraNopBytesForCodeAlign(
- const MCFragment &AF, unsigned &Size) {
- // Calculate Nops Size only when linker relaxation enabled.
- if (!AF.getSubtargetInfo()->hasFeature(LoongArch::FeatureRelax))
- return false;
-
- // Ignore alignment if MaxBytesToEmit is less than the minimum Nop size.
- const unsigned MinNopLen = 4;
- if (AF.getAlignMaxBytesToEmit() < MinNopLen)
- return false;
- Size = AF.getAlignment().value() - MinNopLen;
- return AF.getAlignment() > MinNopLen;
-}
-
-// We need to insert R_LARCH_ALIGN relocation type to indicate the
-// position of Nops and the total bytes of the Nops have been inserted
-// when linker relaxation enabled.
-// The function inserts fixup_loongarch_align fixup which eventually will
-// transfer to R_LARCH_ALIGN relocation type.
-// The improved R_LARCH_ALIGN requires symbol index. The lowest 8 bits of
-// addend represent alignment and the other bits of addend represent the
-// maximum number of bytes to emit. The maximum number of bytes is zero
-// means ignore the emit limit.
-bool LoongArchAsmBackend::shouldInsertFixupForCodeAlign(MCAssembler &Asm,
- MCFragment &AF) {
- // Insert the fixup only when linker relaxation enabled.
- if (!AF.getSubtargetInfo()->hasFeature(LoongArch::FeatureRelax))
- return false;
-
- // Calculate total Nops we need to insert. If there are none to insert
- // then simply return.
- unsigned InsertedNopBytes;
- if (!shouldInsertExtraNopBytesForCodeAlign(AF, InsertedNopBytes))
- return false;
-
- MCSection *Sec = AF.getParent();
- MCContext &Ctx = getContext();
- const MCExpr *Dummy = MCConstantExpr::create(0, Ctx);
- MCFixup Fixup = MCFixup::create(AF.getFixedSize(), Dummy, ELF::R_LARCH_ALIGN);
- unsigned MaxBytesToEmit = AF.getAlignMaxBytesToEmit();
-
- auto createExtendedValue = [&]() {
- const MCSymbolRefExpr *MCSym = getSecToAlignSym()[Sec];
- if (MCSym == nullptr) {
- // Define a marker symbol at the section with an offset of 0.
- MCSymbol *Sym = Ctx.createNamedTempSymbol("la-relax-align");
- Sym->setFragment(&*Sec->getBeginSymbol()->getFragment());
- Asm.registerSymbol(*Sym);
- MCSym = MCSymbolRefExpr::create(Sym, Ctx);
- getSecToAlignSym()[Sec] = MCSym;
- }
- return MCValue::get(&MCSym->getSymbol(), nullptr,
- MaxBytesToEmit << 8 | Log2(AF.getAlignment()));
- };
-
- uint64_t FixedValue = 0;
- MCValue Value = MaxBytesToEmit >= InsertedNopBytes
- ? MCValue::get(InsertedNopBytes)
- : createExtendedValue();
- Asm.getWriter().recordRelocation(AF, Fixup, Value, FixedValue);
-
- return true;
-}
-
bool LoongArchAsmBackend::shouldForceRelocation(const MCFixup &Fixup,
const MCValue &Target) {
switch (Fixup.getKind()) {
@@ -279,6 +211,61 @@ getRelocPairForSize(unsigned Size) {
}
}
+// Linker relaxation may change code size. We have to insert Nops
+// for .align directive when linker relaxation enabled. So then Linker
+// could satisfy alignment by removing Nops.
+// The function returns the total Nops Size we need to insert.
+bool LoongArchAsmBackend::relaxAlign(MCFragment &F, unsigned &Size) {
+ // Use default handling unless linker relaxation is enabled and the
+ // MaxBytesToEmit >= the nop size.
+ if (!F.getSubtargetInfo()->hasFeature(LoongArch::FeatureRelax))
+ return false;
+ const unsigned MinNopLen = 4;
+ unsigned MaxBytesToEmit = F.getAlignMaxBytesToEmit();
+ if (MaxBytesToEmit < MinNopLen)
+ return false;
+
+ Size = F.getAlignment().value() - MinNopLen;
+ if (F.getAlignment() <= MinNopLen)
+ return false;
+
+ // We need to insert R_LARCH_ALIGN relocation type to indicate the
+ // position of Nops and the total bytes of the Nops have been inserted
+ // when linker relaxation enabled.
+ // The function inserts fixup_loongarch_align fixup which eventually will
+ // transfer to R_LARCH_ALIGN relocation type.
+ // The improved R_LARCH_ALIGN requires symbol index. The lowest 8 bits of
+ // addend represent alignment and the other bits of addend represent the
+ // maximum number of bytes to emit. The maximum number of bytes is zero
+ // means ignore the emit limit.
+ MCContext &Ctx = getContext();
+ const MCExpr *Expr = nullptr;
+ if (MaxBytesToEmit >= Size) {
+ Expr = MCConstantExpr::create(Size, getContext());
+ } else {
+ MCSection *Sec = F.getParent();
+ const MCSymbolRefExpr *SymRef = getSecToAlignSym()[Sec];
+ if (SymRef == nullptr) {
+ // Define a marker symbol at the section with an offset of 0.
+ MCSymbol *Sym = Ctx.createNamedTempSymbol("la-relax-align");
+ Sym->setFragment(&*Sec->getBeginSymbol()->getFragment());
+ Asm->registerSymbol(*Sym);
+ SymRef = MCSymbolRefExpr::create(Sym, Ctx);
+ getSecToAlignSym()[Sec] = SymRef;
+ }
+ Expr = MCBinaryExpr::createAdd(
+ SymRef,
+ MCConstantExpr::create((MaxBytesToEmit << 8) | Log2(F.getAlignment()),
+ Ctx),
+ Ctx);
+ }
+ MCFixup Fixup =
+ MCFixup::create(0, Expr, FirstLiteralRelocationKind + ELF::R_LARCH_ALIGN);
+ F.setVarFixups({Fixup});
+ F.getParent()->setLinkerRelaxable();
+ return true;
+}
+
std::pair<bool, bool> LoongArchAsmBackend::relaxLEB128(MCFragment &F,
int64_t &Value) const {
const MCExpr &Expr = F.getLEBValue();
diff --git a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h
index 793e4093b1c9e..3d929fc49f95e 100644
--- a/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h
+++ b/llvm/lib/Target/LoongArch/MCTargetDesc/LoongArchAsmBackend.h
@@ -45,19 +45,13 @@ class LoongArchAsmBackend : public MCAsmBackend {
MutableArrayRef<char> Data, uint64_t Value,
bool IsResolved) override;
- // Return Size with extra Nop Bytes for alignment directive in code section.
- bool shouldInsertExtraNopBytesForCodeAlign(const MCFragment &AF,
- unsigned &Size) override;
-
- // Insert target specific fixup type for alignment directive in code section.
- bool shouldInsertFixupForCodeAlign(MCAssembler &Asm, MCFragment &AF) override;
-
bool shouldForceRelocation(const MCFixup &Fixup, const MCValue &Target);
std::optional<MCFixupKind> getFixupKind(StringRef Name) const override;
MCFixupKindInfo getFixupKindInfo(MCFixupKind Kind) const override;
+ bool relaxAlign(MCFragment &F, unsigned &Size) override;
bool relaxDwarfLineAddr(MCFragment &F, bool &WasRelaxed) const override;
bool relaxDwarfCFA(MCFragment &F, bool &WasRelaxed) const override;
std::pair<bool, bool> relaxLEB128(MCFragment &F,
diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
index 6bc313656f7c1..3d124bace92fe 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
@@ -302,6 +302,25 @@ void RISCVAsmBackend::relaxInstruction(MCInst &Inst,
Inst = std::move(Res);
}
+bool RISCVAsmBackend::relaxAlign(MCFragment &F, unsigned &Size) {
+ // Use default handling unless linker relaxation is enabled and the alignment
+ // is larger than the nop size.
+ const MCSubtargetInfo *STI = F.getSubtargetInfo();
+ if (!STI->hasFeature(RISCV::FeatureRelax))
+ return false;
+ unsigned MinNopLen = STI->hasFeature(RISCV::FeatureStdExtZca) ? 2 : 4;
+ if (F.getAlignment() <= MinNopLen)
+ return false;
+
+ Size = F.getAlignment().value() - MinNopLen;
+ auto *Expr = MCConstantExpr::create(Size, getContext());
+ MCFixup Fixup =
+ MCFixup::create(0, Expr, FirstLiteralRelocationKind + ELF::R_RISCV_ALIGN);
+ F.setVarFixups({Fixup});
+ F.getParent()->setLinkerRelaxable();
+ return true;
+}
+
bool RISCVAsmBackend::relaxDwarfLineAddr(MCFragment &F,
bool &WasRelaxed) const {
MCContext &C = getContext();
@@ -887,55 +906,6 @@ void RISCVAsmBackend::applyFixup(const MCFragment &F, const MCFixup &Fixup,
}
}
-// Linker relaxation may change code size. We have to insert Nops
-// for .align directive when linker relaxation enabled. So then Linker
-// could satisfy alignment by removing Nops.
-// The function return the total Nops Size we need to insert.
-bool RISCVAsmBackend::shouldInsertExtraNopBytesForCodeAlign(
- const MCFragment &AF, unsigned &Size) {
- // Calculate Nops Size only when linker relaxation enabled.
- const MCSubtargetInfo *STI = AF.getSubtargetInfo();
- if (!STI->hasFeature(RISCV::FeatureRelax))
- return false;
-
- unsigned MinNopLen = STI->hasFeature(RISCV::FeatureStdExtZca) ? 2 : 4;
-
- if (AF.getAlignment() <= MinNopLen) {
- return false;
- } else {
- Size = AF.getAlignment().value() - MinNopLen;
- return true;
- }
-}
-
-// We need to insert R_RISCV_ALIGN relocation type to indicate the
-// position of Nops and the total bytes of the Nops have been inserted
-// when linker relaxation en...
[truncated]
|
aengelke
reviewed
Jul 18, 2025
MaskRay
added a commit
to MaskRay/llvm-project
that referenced
this pull request
Jul 19, 2025
Previously, two MCAsmBackend hooks were used, with shouldInsertFixupForCodeAlign calling getWriter().recordRelocation directly, bypassing generic code. This patch: * Introduces MCAsmBackend::relaxAlign to replace the two hooks. * Tracks padding size using VarContentStart and VarContentEnd (content is arbitrary). * Move setLinkerRelaxable from MCObjectStreamer::emitCodeAlignment to the backends. Pull Request: llvm#149465
Created using spr 1.3.5-bogner [skip ci]
Created using spr 1.3.5-bogner
Created using spr 1.3.5-bogner [skip ci]
Created using spr 1.3.5-bogner
MaskRay
added a commit
to MaskRay/llvm-project
that referenced
this pull request
Jul 19, 2025
Previously, two MCAsmBackend hooks were used, with shouldInsertFixupForCodeAlign calling getWriter().recordRelocation directly, bypassing generic code. This patch: * Introduces MCAsmBackend::relaxAlign to replace the two hooks. * Tracks padding size using VarContentStart and VarContentEnd (content is arbitrary). * Move setLinkerRelaxable from MCObjectStreamer::emitCodeAlignment to the backends. Pull Request: llvm#149465
MaskRay
added a commit
to MaskRay/llvm-project
that referenced
this pull request
Jul 19, 2025
Previously, two MCAsmBackend hooks were used, with shouldInsertFixupForCodeAlign calling getWriter().recordRelocation directly, bypassing generic code. This patch: * Introduces MCAsmBackend::relaxAlign to replace the two hooks. * Tracks padding size using VarContentStart and VarContentEnd (content is arbitrary). * Move setLinkerRelaxable from MCObjectStreamer::emitCodeAlignment to the backends. Pull Request: llvm#149465
Created using spr 1.3.5-bogner [skip ci]
MaskRay
added a commit
to MaskRay/llvm-project
that referenced
this pull request
Jul 20, 2025
Previously, two MCAsmBackend hooks were used, with shouldInsertFixupForCodeAlign calling getWriter().recordRelocation directly, bypassing generic code. This patch: * Introduces MCAsmBackend::relaxAlign to replace the two hooks. * Tracks padding size using VarContentStart and VarContentEnd (content is arbitrary). * Move setLinkerRelaxable from MCObjectStreamer::emitCodeAlignment to the backends. Pull Request: llvm#149465
aengelke
approved these changes
Jul 20, 2025
llvm/lib/MC/MCAssembler.cpp
Outdated
| if (!AlignFixup && Size > F.getAlignMaxBytesToEmit()) | ||
| Size = 0; | ||
| // Update the variable tail size. The content is ignored. | ||
| F.VarContentEnd = F.VarContentStart + Size; |
There was a problem hiding this comment.
NB: VarContentStart should be zero here, it is never set for FT_Align. For clarity, I'd suggest:
Suggested change
| F.VarContentEnd = F.VarContentStart + Size; | |
| F.VarContentStart = 0; | |
| F.VarContentEnd = Size; |
There was a problem hiding this comment.
Agree! Let me try assert(F.VarContentStart == 0);
|
Next steps:
|
Created using spr 1.3.5-bogner [skip ci]
Created using spr 1.3.5-bogner
MaskRay
changed the base branch from
users/MaskRay/spr/main.mc-refactor-ft_align-fragments-when-linker-relaxation-is-enabled
to
main
MaskRay
deleted the
users/MaskRay/spr/mc-refactor-ft_align-fragments-when-linker-relaxation-is-enabled
branch
llvm-sync bot
pushed a commit
to arm/arm-toolchain
that referenced
this pull request
Jul 20, 2025
…enabled Previously, two MCAsmBackend hooks were used, with shouldInsertFixupForCodeAlign calling getWriter().recordRelocation directly, bypassing generic code. This patch: * Introduces MCAsmBackend::relaxAlign to replace the two hooks. * Tracks padding size using VarContentEnd (content is ignored). * Move setLinkerRelaxable from MCObjectStreamer::emitCodeAlignment to the backends. Pull Request: llvm/llvm-project#149465
This was referenced Jul 23, 2025
cachemeifyoucan
pushed a commit
to cachemeifyoucan/llvm-project
that referenced
this pull request
Jul 25, 2025
Previously, two MCAsmBackend hooks were used, with shouldInsertFixupForCodeAlign calling getWriter().recordRelocation directly, bypassing generic code. This patch: * Introduces MCAsmBackend::relaxAlign to replace the two hooks. * Tracks padding size using VarContentEnd (content is ignored). * Move setLinkerRelaxable from MCObjectStreamer::emitCodeAlignment to the backends. Pull Request: llvm#149465
cachemeifyoucan
pushed a commit
to cachemeifyoucan/llvm-project
that referenced
this pull request
Jul 25, 2025
…laxation targets after llvm#149465 Similar to 13549fd
cachemeifyoucan
pushed a commit
to cachemeifyoucan/llvm-project
that referenced
this pull request
Jul 25, 2025
Previously, two MCAsmBackend hooks were used, with shouldInsertFixupForCodeAlign calling getWriter().recordRelocation directly, bypassing generic code. This patch: * Introduces MCAsmBackend::relaxAlign to replace the two hooks. * Tracks padding size using VarContentEnd (content is ignored). * Move setLinkerRelaxable from MCObjectStreamer::emitCodeAlignment to the backends. Pull Request: llvm#149465
cachemeifyoucan
pushed a commit
to cachemeifyoucan/llvm-project
that referenced
this pull request
Jul 25, 2025
…laxation targets after llvm#149465 Similar to 13549fd
cachemeifyoucan
pushed a commit
to swiftlang/llvm-project
that referenced
this pull request
Jul 25, 2025
Previously, two MCAsmBackend hooks were used, with shouldInsertFixupForCodeAlign calling getWriter().recordRelocation directly, bypassing generic code. This patch: * Introduces MCAsmBackend::relaxAlign to replace the two hooks. * Tracks padding size using VarContentEnd (content is ignored). * Move setLinkerRelaxable from MCObjectStreamer::emitCodeAlignment to the backends. Pull Request: llvm#149465
cachemeifyoucan
pushed a commit
to swiftlang/llvm-project
that referenced
this pull request
Jul 25, 2025
…laxation targets after llvm#149465 Similar to 13549fd
mahesh-attarde
pushed a commit
to mahesh-attarde/llvm-project
that referenced
this pull request
Jul 28, 2025
Previously, two MCAsmBackend hooks were used, with shouldInsertFixupForCodeAlign calling getWriter().recordRelocation directly, bypassing generic code. This patch: * Introduces MCAsmBackend::relaxAlign to replace the two hooks. * Tracks padding size using VarContentEnd (content is ignored). * Move setLinkerRelaxable from MCObjectStreamer::emitCodeAlignment to the backends. Pull Request: llvm#149465
mahesh-attarde
pushed a commit
to mahesh-attarde/llvm-project
that referenced
this pull request
Jul 28, 2025
…laxation targets after llvm#149465 Similar to 13549fd
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Previously, two MCAsmBackend hooks were used, with
shouldInsertFixupForCodeAlign calling getWriter().recordRelocation
directly, bypassing generic code.
This patch: