llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-backend-hexagon Author: None (llvmbot) <details> <summary>Changes</summary> Backport 4eb5450f630849ee0518487de38d857fbe5b1aee Requested by: @<!-- -->MaskRay --- Full diff: https://github.com/llvm/llvm-project/pull/101254.diff 7 Files Affected: - (modified) llvm/include/llvm/MC/MCAsmBackend.h (+2-3) - (modified) llvm/include/llvm/MC/MCAssembler.h (+2-2) - (modified) llvm/include/llvm/MC/MCSection.h (+5) - (modified) llvm/lib/MC/MCAssembler.cpp (+37-40) - (modified) llvm/lib/MC/MCSection.cpp (+2-2) - (modified) llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp (+2-2) - (modified) llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp (+21-5) ``````````diff diff --git a/llvm/include/llvm/MC/MCAsmBackend.h b/llvm/include/llvm/MC/MCAsmBackend.h index d1d1814dd8b52..3f88ac02cd92a 100644 --- a/llvm/include/llvm/MC/MCAsmBackend.h +++ b/llvm/include/llvm/MC/MCAsmBackend.h @@ -217,9 +217,8 @@ class MCAsmBackend { virtual bool writeNopData(raw_ostream &OS, uint64_t Count, const MCSubtargetInfo *STI) const = 0; - // Return true if fragment offsets have been adjusted and an extra layout - // iteration is needed. - virtual bool finishLayout(const MCAssembler &Asm) const { return false; } + /// Give backend an opportunity to finish layout after relaxation + virtual void finishLayout(MCAssembler const &Asm) const {} /// Handle any target-specific assembler flags. By default, do nothing. virtual void handleAssemblerFlag(MCAssemblerFlag Flag) {} diff --git a/llvm/include/llvm/MC/MCAssembler.h b/llvm/include/llvm/MC/MCAssembler.h index d9752912ee66a..c6fa48128d189 100644 --- a/llvm/include/llvm/MC/MCAssembler.h +++ b/llvm/include/llvm/MC/MCAssembler.h @@ -111,7 +111,6 @@ class MCAssembler { /// Check whether the given fragment needs relaxation. bool fragmentNeedsRelaxation(const MCRelaxableFragment *IF) const; - void layoutSection(MCSection &Sec); /// Perform one layout iteration and return true if any offsets /// were adjusted. bool layoutOnce(); @@ -148,9 +147,10 @@ class MCAssembler { uint64_t computeFragmentSize(const MCFragment &F) const; void layoutBundle(MCFragment *Prev, MCFragment *F) const; + void ensureValid(MCSection &Sec) const; // Get the offset of the given fragment inside its containing section. - uint64_t getFragmentOffset(const MCFragment &F) const { return F.Offset; } + uint64_t getFragmentOffset(const MCFragment &F) const; uint64_t getSectionAddressSize(const MCSection &Sec) const; uint64_t getSectionFileSize(const MCSection &Sec) const; diff --git a/llvm/include/llvm/MC/MCSection.h b/llvm/include/llvm/MC/MCSection.h index 1289d6f6f9f65..dcdcd094fa17b 100644 --- a/llvm/include/llvm/MC/MCSection.h +++ b/llvm/include/llvm/MC/MCSection.h @@ -99,6 +99,8 @@ class MCSection { /// Whether this section has had instructions emitted into it. bool HasInstructions : 1; + bool HasLayout : 1; + bool IsRegistered : 1; bool IsText : 1; @@ -167,6 +169,9 @@ class MCSection { bool hasInstructions() const { return HasInstructions; } void setHasInstructions(bool Value) { HasInstructions = Value; } + bool hasLayout() const { return HasLayout; } + void setHasLayout(bool Value) { HasLayout = Value; } + bool isRegistered() const { return IsRegistered; } void setIsRegistered(bool Value) { IsRegistered = Value; } diff --git a/llvm/lib/MC/MCAssembler.cpp b/llvm/lib/MC/MCAssembler.cpp index ceeb7af0fecc4..c3da4bb5cc363 100644 --- a/llvm/lib/MC/MCAssembler.cpp +++ b/llvm/lib/MC/MCAssembler.cpp @@ -432,6 +432,28 @@ void MCAssembler::layoutBundle(MCFragment *Prev, MCFragment *F) const { DF->Offset = EF->Offset; } +void MCAssembler::ensureValid(MCSection &Sec) const { + if (Sec.hasLayout()) + return; + Sec.setHasLayout(true); + MCFragment *Prev = nullptr; + uint64_t Offset = 0; + for (MCFragment &F : Sec) { + F.Offset = Offset; + if (isBundlingEnabled() && F.hasInstructions()) { + layoutBundle(Prev, &F); + Offset = F.Offset; + } + Offset += computeFragmentSize(F); + Prev = &F; + } +} + +uint64_t MCAssembler::getFragmentOffset(const MCFragment &F) const { + ensureValid(*F.getParent()); + return F.Offset; +} + // Simple getSymbolOffset helper for the non-variable case. static bool getLabelOffset(const MCAssembler &Asm, const MCSymbol &S, bool ReportError, uint64_t &Val) { @@ -916,20 +938,22 @@ void MCAssembler::layout() { // Layout until everything fits. this->HasLayout = true; - for (MCSection &Sec : *this) - layoutSection(Sec); while (layoutOnce()) { + if (getContext().hadError()) + return; + // Size of fragments in one section can depend on the size of fragments in + // another. If any fragment has changed size, we have to re-layout (and + // as a result possibly further relax) all. + for (MCSection &Sec : *this) + Sec.setHasLayout(false); } DEBUG_WITH_TYPE("mc-dump", { errs() << "assembler backend - post-relaxation\n--\n"; dump(); }); - // Some targets might want to adjust fragment offsets. If so, perform another - // layout loop. - if (getBackend().finishLayout(*this)) - for (MCSection &Sec : *this) - layoutSection(Sec); + // Finalize the layout, including fragment lowering. + getBackend().finishLayout(*this); DEBUG_WITH_TYPE("mc-dump", { errs() << "assembler backend - final-layout\n--\n"; @@ -1282,42 +1306,15 @@ bool MCAssembler::relaxFragment(MCFragment &F) { } } -void MCAssembler::layoutSection(MCSection &Sec) { - MCFragment *Prev = nullptr; - uint64_t Offset = 0; - for (MCFragment &F : Sec) { - F.Offset = Offset; - if (LLVM_UNLIKELY(isBundlingEnabled())) { - if (F.hasInstructions()) { - layoutBundle(Prev, &F); - Offset = F.Offset; - } - Prev = &F; - } - Offset += computeFragmentSize(F); - } -} - bool MCAssembler::layoutOnce() { ++stats::RelaxationSteps; - // Size of fragments in one section can depend on the size of fragments in - // another. If any fragment has changed size, we have to re-layout (and - // as a result possibly further relax) all. - bool ChangedAny = false; - for (MCSection &Sec : *this) { - for (;;) { - bool Changed = false; - for (MCFragment &F : Sec) - if (relaxFragment(F)) - Changed = true; - ChangedAny |= Changed; - if (!Changed) - break; - layoutSection(Sec); - } - } - return ChangedAny; + bool Changed = false; + for (MCSection &Sec : *this) + for (MCFragment &Frag : Sec) + if (relaxFragment(Frag)) + Changed = true; + return Changed; } #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) diff --git a/llvm/lib/MC/MCSection.cpp b/llvm/lib/MC/MCSection.cpp index 97e87a41c8ce5..8c2ee5635a49c 100644 --- a/llvm/lib/MC/MCSection.cpp +++ b/llvm/lib/MC/MCSection.cpp @@ -23,8 +23,8 @@ using namespace llvm; MCSection::MCSection(SectionVariant V, StringRef Name, bool IsText, bool IsVirtual, MCSymbol *Begin) : Begin(Begin), BundleGroupBeforeFirstInst(false), HasInstructions(false), - IsRegistered(false), IsText(IsText), IsVirtual(IsVirtual), Name(Name), - Variant(V) { + HasLayout(false), IsRegistered(false), IsText(IsText), + IsVirtual(IsVirtual), Name(Name), Variant(V) { DummyFragment.setParent(this); // The initial subsection number is 0. Create a fragment list. CurFragList = &Subsections.emplace_back(0u, FragList{}).second; diff --git a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp index 1570493b765ca..6acc37e599f2e 100644 --- a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp +++ b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp @@ -702,7 +702,7 @@ class HexagonAsmBackend : public MCAsmBackend { return true; } - bool finishLayout(const MCAssembler &Asm) const override { + void finishLayout(MCAssembler const &Asm) const override { SmallVector<MCFragment *> Frags; for (MCSection &Sec : Asm) { Frags.clear(); @@ -747,6 +747,7 @@ class HexagonAsmBackend : public MCAsmBackend { //assert(!Error); (void)Error; ReplaceInstruction(Asm.getEmitter(), RF, Inst); + Sec.setHasLayout(false); Size = 0; // Only look back one instruction break; } @@ -756,7 +757,6 @@ class HexagonAsmBackend : public MCAsmBackend { } } } - return true; } }; // class HexagonAsmBackend diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp index fcc61d0a5e2f6..67d993a51ad97 100644 --- a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp +++ b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp @@ -201,7 +201,7 @@ class X86AsmBackend : public MCAsmBackend { bool padInstructionEncoding(MCRelaxableFragment &RF, MCCodeEmitter &Emitter, unsigned &RemainingSize) const; - bool finishLayout(const MCAssembler &Asm) const override; + void finishLayout(const MCAssembler &Asm) const override; unsigned getMaximumNopSize(const MCSubtargetInfo &STI) const override; @@ -856,7 +856,7 @@ bool X86AsmBackend::padInstructionEncoding(MCRelaxableFragment &RF, return Changed; } -bool X86AsmBackend::finishLayout(const MCAssembler &Asm) const { +void X86AsmBackend::finishLayout(MCAssembler const &Asm) const { // See if we can further relax some instructions to cut down on the number of // nop bytes required for code alignment. The actual win is in reducing // instruction count, not number of bytes. Modern X86-64 can easily end up @@ -864,7 +864,7 @@ bool X86AsmBackend::finishLayout(const MCAssembler &Asm) const { // (i.e. eliminate nops) even at the cost of increasing the size and // complexity of others. if (!X86PadForAlign && !X86PadForBranchAlign) - return false; + return; // The processed regions are delimitered by LabeledFragments. -g may have more // MCSymbols and therefore different relaxation results. X86PadForAlign is @@ -911,6 +911,9 @@ bool X86AsmBackend::finishLayout(const MCAssembler &Asm) const { continue; } +#ifndef NDEBUG + const uint64_t OrigOffset = Asm.getFragmentOffset(F); +#endif const uint64_t OrigSize = Asm.computeFragmentSize(F); // To keep the effects local, prefer to relax instructions closest to @@ -923,7 +926,8 @@ bool X86AsmBackend::finishLayout(const MCAssembler &Asm) const { // Give the backend a chance to play any tricks it wishes to increase // the encoding size of the given instruction. Target independent code // will try further relaxation, but target's may play further tricks. - padInstructionEncoding(RF, Asm.getEmitter(), RemainingSize); + if (padInstructionEncoding(RF, Asm.getEmitter(), RemainingSize)) + Sec.setHasLayout(false); // If we have an instruction which hasn't been fully relaxed, we can't // skip past it and insert bytes before it. Changing its starting @@ -940,6 +944,14 @@ bool X86AsmBackend::finishLayout(const MCAssembler &Asm) const { if (F.getKind() == MCFragment::FT_BoundaryAlign) cast<MCBoundaryAlignFragment>(F).setSize(RemainingSize); +#ifndef NDEBUG + const uint64_t FinalOffset = Asm.getFragmentOffset(F); + const uint64_t FinalSize = Asm.computeFragmentSize(F); + assert(OrigOffset + OrigSize == FinalOffset + FinalSize && + "can't move start of next fragment!"); + assert(FinalSize == RemainingSize && "inconsistent size computation?"); +#endif + // If we're looking at a boundary align, make sure we don't try to pad // its target instructions for some following directive. Doing so would // break the alignment of the current boundary align. @@ -953,7 +965,11 @@ bool X86AsmBackend::finishLayout(const MCAssembler &Asm) const { } } - return true; + // The layout is done. Mark every fragment as valid. + for (MCSection &Section : Asm) { + Asm.getFragmentOffset(*Section.curFragList()->Tail); + Asm.computeFragmentSize(*Section.curFragList()->Tail); + } } unsigned X86AsmBackend::getMaximumNopSize(const MCSubtargetInfo &STI) const { `````````` </details> https://github.com/llvm/llvm-project/pull/101254 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
