From 43ca0e9eb880dc211e94b2b2a05de715c321ef4e Mon Sep 17 00:00:00 2001 From: Fangrui Song Date: Fri, 17 May 2019 02:51:54 +0000 Subject: [ARM] Support .reloc *, R_ARM_NONE, * R_ARM_NONE can be used to create references among sections. When --gc-sections is used, the referenced section will be retained if the origin section is retained. Add a generic MCFixupKind FK_NONE as this kind of no-op relocation is ubiquitous on ELF and COFF, and probably available on many other binary formats. See D62014. Reviewed By: peter.smith Differential Revision: https://reviews.llvm.org/D61992 llvm-svn: 360980 --- llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp | 18 +++++++++++++++++- llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.h | 2 ++ .../lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp | 2 ++ llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp | 4 +--- .../Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp | 2 +- llvm/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h | 5 +---- 6 files changed, 24 insertions(+), 9 deletions(-) (limited to 'llvm/lib/Target') diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp index b846ca0699b..538bc2594c3 100644 --- a/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp +++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp @@ -46,6 +46,13 @@ public: }; } // end anonymous namespace +Optional ARMAsmBackend::getFixupKind(StringRef Name) const { + if (STI.getTargetTriple().isOSBinFormatELF() && Name == "R_ARM_NONE") + return FK_NONE; + + return MCAsmBackend::getFixupKind(Name); +} + const MCFixupKindInfo &ARMAsmBackend::getFixupKindInfo(MCFixupKind Kind) const { const static MCFixupKindInfo InfosLE[ARM::NumTargetFixupKinds] = { // This table *must* be in the order that the fixup_* kinds are defined in @@ -383,6 +390,7 @@ unsigned ARMAsmBackend::adjustFixupValue(const MCAssembler &Asm, default: Ctx.reportError(Fixup.getLoc(), "bad relocation fixup type"); return 0; + case FK_NONE: case FK_Data_1: case FK_Data_2: case FK_Data_4: @@ -761,7 +769,9 @@ bool ARMAsmBackend::shouldForceRelocation(const MCAssembler &Asm, const MCSymbolRefExpr *A = Target.getSymA(); const MCSymbol *Sym = A ? &A->getSymbol() : nullptr; const unsigned FixupKind = Fixup.getKind() ; - if ((unsigned)Fixup.getKind() == ARM::fixup_arm_thumb_bl) { + if (FixupKind == FK_NONE) + return true; + if (FixupKind == ARM::fixup_arm_thumb_bl) { assert(Sym && "How did we resolve this?"); // If the symbol is external the linker will handle it. @@ -803,6 +813,9 @@ static unsigned getFixupKindNumBytes(unsigned Kind) { default: llvm_unreachable("Unknown fixup kind!"); + case FK_NONE: + return 0; + case FK_Data_1: case ARM::fixup_arm_thumb_bcc: case ARM::fixup_arm_thumb_cp: @@ -857,6 +870,9 @@ static unsigned getFixupKindContainerSizeBytes(unsigned Kind) { default: llvm_unreachable("Unknown fixup kind!"); + case FK_NONE: + return 0; + case FK_Data_1: return 1; case FK_Data_2: diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.h b/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.h index 52abc2f20e0..67722a5e5b6 100644 --- a/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.h +++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.h @@ -37,6 +37,8 @@ public: // different. bool hasNOP() const { return STI.getFeatureBits()[ARM::HasV6T2Ops]; } + Optional getFixupKind(StringRef Name) const override; + const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override; bool shouldForceRelocation(const MCAssembler &Asm, const MCFixup &Fixup, diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp index a93202b8202..1d51a9696cd 100644 --- a/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp +++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMELFObjectWriter.cpp @@ -143,6 +143,8 @@ unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target, default: Ctx.reportFatalError(Fixup.getLoc(), "unsupported relocation on symbol"); return ELF::R_ARM_NONE; + case FK_NONE: + return ELF::R_ARM_NONE; case FK_Data_1: switch (Modifier) { default: diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp index 65e2a902182..859f9cbbca0 100644 --- a/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp +++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp @@ -302,7 +302,7 @@ void MipsAsmBackend::applyFixup(const MCAssembler &Asm, const MCFixup &Fixup, Optional MipsAsmBackend::getFixupKind(StringRef Name) const { return StringSwitch>(Name) - .Case("R_MIPS_NONE", (MCFixupKind)Mips::fixup_Mips_NONE) + .Case("R_MIPS_NONE", FK_NONE) .Case("R_MIPS_32", FK_Data_4) .Case("R_MIPS_GOT_PAGE", (MCFixupKind)Mips::fixup_Mips_GOT_PAGE) .Case("R_MIPS_CALL_HI16", (MCFixupKind)Mips::fixup_Mips_CALL_HI16) @@ -350,7 +350,6 @@ getFixupKindInfo(MCFixupKind Kind) const { // MipsFixupKinds.h. // // name offset bits flags - { "fixup_Mips_NONE", 0, 0, 0 }, { "fixup_Mips_16", 0, 16, 0 }, { "fixup_Mips_32", 0, 32, 0 }, { "fixup_Mips_REL32", 0, 32, 0 }, @@ -430,7 +429,6 @@ getFixupKindInfo(MCFixupKind Kind) const { // MipsFixupKinds.h. // // name offset bits flags - { "fixup_Mips_NONE", 0, 0, 0 }, { "fixup_Mips_16", 16, 16, 0 }, { "fixup_Mips_32", 0, 32, 0 }, { "fixup_Mips_REL32", 0, 32, 0 }, diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp index c11e2ce85e8..cf7bae98a27 100644 --- a/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp +++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp @@ -222,7 +222,7 @@ unsigned MipsELFObjectWriter::getRelocType(MCContext &Ctx, unsigned Kind = (unsigned)Fixup.getKind(); switch (Kind) { - case Mips::fixup_Mips_NONE: + case FK_NONE: return ELF::R_MIPS_NONE; case FK_Data_1: Ctx.reportError(Fixup.getLoc(), diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h b/llvm/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h index 939afefabe9..b83d822bd8d 100644 --- a/llvm/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h +++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsFixupKinds.h @@ -22,11 +22,8 @@ namespace Mips { // in MipsAsmBackend.cpp. // enum Fixups { - // Branch fixups resulting in R_MIPS_NONE. - fixup_Mips_NONE = FirstTargetFixupKind, - // Branch fixups resulting in R_MIPS_16. - fixup_Mips_16, + fixup_Mips_16 = FirstTargetFixupKind, // Pure 32 bit data fixup resulting in - R_MIPS_32. fixup_Mips_32, -- cgit v1.2.3