From: Daniel Sanders Date: Tue, 26 May 2015 10:19:18 +0000 (+0000) Subject: [mips] Make TTypeEncoding indirect to allow .eh_frame to be read-only. X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=bda72d8098c1f7f304de89ebed72b50a7feed674;p=oota-llvm.git [mips] Make TTypeEncoding indirect to allow .eh_frame to be read-only. Summary: Following on from r209907 which made personality encodings indirect, do the same for TType encodings. This fixes the case where a try/catch block needs to generate references to, for example, std::exception in the .gcc_except_table. This commit uses DW_EH_PE_sdata8 for N64 as far as is possible at the moment. However, it is possible to end up with DW_EH_PE_sdata4 when a TargetMachine is not available. There's no risk of issues with inconsistency here since the tables are self describing but it does mean there is a small chance of the PC-relative offset being out of range for particularly large programs. Reviewers: petarj Reviewed By: petarj Subscribers: srhines, joerg, tberghammer, llvm-commits Differential Revision: http://reviews.llvm.org/D9669 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238190 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/include/llvm/MC/MCObjectFileInfo.h b/include/llvm/MC/MCObjectFileInfo.h index f28b9c668cd..c3e2a8b4e4e 100644 --- a/include/llvm/MC/MCObjectFileInfo.h +++ b/include/llvm/MC/MCObjectFileInfo.h @@ -352,6 +352,8 @@ private: /// void InitEHFrameSection(); + virtual unsigned SelectMipsTTypeEncoding() const; + public: const Triple &getTargetTriple() const { return TT; } }; diff --git a/lib/MC/MCObjectFileInfo.cpp b/lib/MC/MCObjectFileInfo.cpp index e99f036af16..c189d19c12d 100644 --- a/lib/MC/MCObjectFileInfo.cpp +++ b/lib/MC/MCObjectFileInfo.cpp @@ -324,10 +324,13 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) { case Triple::mipsel: case Triple::mips64: case Triple::mips64el: - // MIPS uses indirect pointer to refer personality functions, so that the - // eh_frame section can be read-only. DW.ref.personality will be generated - // for relocation. + // MIPS uses indirect pointer to refer personality functions and types, so + // that the eh_frame section can be read-only. DW.ref.personality will be + // generated for relocation. PersonalityEncoding = dwarf::DW_EH_PE_indirect; + TTypeEncoding = SelectMipsTTypeEncoding(); + // We don't support PC-relative LSDA references in GAS so we use the default + // DW_EH_PE_absptr for those. break; case Triple::ppc64: case Triple::ppc64le: @@ -793,3 +796,11 @@ void MCObjectFileInfo::InitEHFrameSection() { COFF::IMAGE_SCN_MEM_WRITE, SectionKind::getDataRel()); } + +unsigned MCObjectFileInfo::SelectMipsTTypeEncoding() const { + // FIXME: The N64 ABI ought to use DW_EH_PE_sdata8 but we can't + // identify N64 from just a triple. We currently fix this by + // overriding this function in MipsTargetObjectFile. + return dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | + dwarf::DW_EH_PE_sdata4; +} diff --git a/lib/Target/Mips/MipsTargetObjectFile.cpp b/lib/Target/Mips/MipsTargetObjectFile.cpp index 0f2db6039b6..adbe526376e 100644 --- a/lib/Target/Mips/MipsTargetObjectFile.cpp +++ b/lib/Target/Mips/MipsTargetObjectFile.cpp @@ -37,6 +37,7 @@ ExternSData("mextern-sdata", cl::Hidden, cl::init(true)); void MipsTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM){ + this->TM = &static_cast(TM); TargetLoweringObjectFileELF::Initialize(Ctx, TM); InitializeELF(TM.Options.UseInitArray); @@ -45,7 +46,6 @@ void MipsTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM){ SmallBSSSection = getContext().getELFSection(".sbss", ELF::SHT_NOBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC); - this->TM = &static_cast(TM); } // A address must be loaded from a small section if its size is less than the @@ -146,3 +146,9 @@ MipsTargetObjectFile::getSectionForConstant(SectionKind Kind, // Otherwise, we work the same as ELF. return TargetLoweringObjectFileELF::getSectionForConstant(Kind, C); } + +unsigned MipsTargetObjectFile::SelectMipsTTypeEncoding() const { + return dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | + (TM->getABI().ArePtrs64bit() ? dwarf::DW_EH_PE_sdata8 + : dwarf::DW_EH_PE_sdata4); +} diff --git a/lib/Target/Mips/MipsTargetObjectFile.h b/lib/Target/Mips/MipsTargetObjectFile.h index 725f2ffd93d..72338d275f8 100644 --- a/lib/Target/Mips/MipsTargetObjectFile.h +++ b/lib/Target/Mips/MipsTargetObjectFile.h @@ -41,6 +41,8 @@ class MipsTargetMachine; MCSection *getSectionForConstant(SectionKind Kind, const Constant *C) const override; + + unsigned SelectMipsTTypeEncoding() const override; }; } // end namespace llvm diff --git a/test/CodeGen/Mips/ehframe-indirect.ll b/test/CodeGen/Mips/ehframe-indirect.ll index f124881a472..a4a82fc352e 100644 --- a/test/CodeGen/Mips/ehframe-indirect.ll +++ b/test/CodeGen/Mips/ehframe-indirect.ll @@ -1,9 +1,11 @@ -; RUN: llc -mtriple=mipsel-linux-gnu < %s | FileCheck -check-prefix=ALL -check-prefix=O32 %s -; RUN: llc -mtriple=mipsel-linux-android < %s | FileCheck -check-prefix=ALL -check-prefix=O32 %s -; RUN: llc -mtriple=mips64el-linux-gnu -target-abi=n32 < %s | FileCheck -check-prefix=ALL -check-prefix=N32 %s -; RUN: llc -mtriple=mips64el-linux-android -target-abi=n32 < %s | FileCheck -check-prefix=ALL -check-prefix=N32 %s -; RUN: llc -mtriple=mips64el-linux-gnu < %s | FileCheck -check-prefix=ALL -check-prefix=N64 %s -; RUN: llc -mtriple=mips64el-linux-android < %s | FileCheck -check-prefix=ALL -check-prefix=N64 %s +; RUN: llc -mtriple=mipsel-linux-gnu < %s -asm-verbose | FileCheck -check-prefix=ALL -check-prefix=O32 %s +; RUN: llc -mtriple=mipsel-linux-android < %s -asm-verbose | FileCheck -check-prefix=ALL -check-prefix=O32 %s +; RUN: llc -mtriple=mips64el-linux-gnu -target-abi=n32 < %s -asm-verbose | FileCheck -check-prefix=ALL -check-prefix=N32 %s +; RUN: llc -mtriple=mips64el-linux-android -target-abi=n32 < %s -asm-verbose | FileCheck -check-prefix=ALL -check-prefix=N32 %s +; RUN: llc -mtriple=mips64el-linux-gnu < %s -asm-verbose | FileCheck -check-prefix=ALL -check-prefix=N64 %s +; RUN: llc -mtriple=mips64el-linux-android < %s -asm-verbose | FileCheck -check-prefix=ALL -check-prefix=N64 %s + +@_ZTISt9exception = external constant i8* define i32 @main() { ; ALL: .cfi_startproc @@ -16,7 +18,9 @@ entry: lpad: %0 = landingpad { i8*, i32 } personality i8* - bitcast (i32 (...)* @__gxx_personality_v0 to i8*) catch i8* null + bitcast (i32 (...)* @__gxx_personality_v0 to i8*) + catch i8* null + catch i8* bitcast (i8** @_ZTISt9exception to i8*) ret i32 0 cont: @@ -28,6 +32,18 @@ declare i32 @__gxx_personality_v0(...) declare void @foo() +; ALL: GCC_except_table{{[0-9]+}}: +; O32: .byte 155 # @TType Encoding = indirect pcrel sdata4 +; N32: .byte 155 # @TType Encoding = indirect pcrel sdata4 +; N64: .byte 156 # @TType Encoding = indirect pcrel sdata8 +; ALL: $[[PC_LABEL:tmp[0-9]+]]: +; O32: .4byte ($_ZTISt9exception.DW.stub)-($[[PC_LABEL]]) +; N32: .4byte ($_ZTISt9exception.DW.stub)-($[[PC_LABEL]]) +; N64: .8byte ($_ZTISt9exception.DW.stub)-($[[PC_LABEL]]) +; ALL: $_ZTISt9exception.DW.stub: +; O32: .4byte _ZTISt9exception +; N32: .4byte _ZTISt9exception +; N64: .8byte _ZTISt9exception ; ALL: .hidden DW.ref.__gxx_personality_v0 ; ALL: .weak DW.ref.__gxx_personality_v0 ; ALL: .section .data.DW.ref.__gxx_personality_v0,"aGw",@progbits,DW.ref.__gxx_personality_v0,comdat