[llvm] r238190 - [mips] Make TTypeEncoding indirect to allow .eh_frame to be read-only.
Daniel Sanders
daniel.sanders at imgtec.com
Tue May 26 03:19:18 PDT 2015
Author: dsanders
Date: Tue May 26 05:19:18 2015
New Revision: 238190
URL: http://llvm.org/viewvc/llvm-project?rev=238190&view=rev
Log:
[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
Modified:
llvm/trunk/include/llvm/MC/MCObjectFileInfo.h
llvm/trunk/lib/MC/MCObjectFileInfo.cpp
llvm/trunk/lib/Target/Mips/MipsTargetObjectFile.cpp
llvm/trunk/lib/Target/Mips/MipsTargetObjectFile.h
llvm/trunk/test/CodeGen/Mips/ehframe-indirect.ll
Modified: llvm/trunk/include/llvm/MC/MCObjectFileInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCObjectFileInfo.h?rev=238190&r1=238189&r2=238190&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCObjectFileInfo.h (original)
+++ llvm/trunk/include/llvm/MC/MCObjectFileInfo.h Tue May 26 05:19:18 2015
@@ -352,6 +352,8 @@ private:
///
void InitEHFrameSection();
+ virtual unsigned SelectMipsTTypeEncoding() const;
+
public:
const Triple &getTargetTriple() const { return TT; }
};
Modified: llvm/trunk/lib/MC/MCObjectFileInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCObjectFileInfo.cpp?rev=238190&r1=238189&r2=238190&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCObjectFileInfo.cpp (original)
+++ llvm/trunk/lib/MC/MCObjectFileInfo.cpp Tue May 26 05:19:18 2015
@@ -324,10 +324,13 @@ void MCObjectFileInfo::InitELFMCObjectFi
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::InitEHFrameSectio
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;
+}
Modified: llvm/trunk/lib/Target/Mips/MipsTargetObjectFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Mips/MipsTargetObjectFile.cpp?rev=238190&r1=238189&r2=238190&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Mips/MipsTargetObjectFile.cpp (original)
+++ llvm/trunk/lib/Target/Mips/MipsTargetObjectFile.cpp Tue May 26 05:19:18 2015
@@ -37,6 +37,7 @@ ExternSData("mextern-sdata", cl::Hidden,
cl::init(true));
void MipsTargetObjectFile::Initialize(MCContext &Ctx, const TargetMachine &TM){
+ this->TM = &static_cast<const MipsTargetMachine &>(TM);
TargetLoweringObjectFileELF::Initialize(Ctx, TM);
InitializeELF(TM.Options.UseInitArray);
@@ -45,7 +46,6 @@ void MipsTargetObjectFile::Initialize(MC
SmallBSSSection = getContext().getELFSection(".sbss", ELF::SHT_NOBITS,
ELF::SHF_WRITE | ELF::SHF_ALLOC);
- this->TM = &static_cast<const MipsTargetMachine &>(TM);
}
// A address must be loaded from a small section if its size is less than the
@@ -146,3 +146,9 @@ MipsTargetObjectFile::getSectionForConst
// 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);
+}
Modified: llvm/trunk/lib/Target/Mips/MipsTargetObjectFile.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Mips/MipsTargetObjectFile.h?rev=238190&r1=238189&r2=238190&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Mips/MipsTargetObjectFile.h (original)
+++ llvm/trunk/lib/Target/Mips/MipsTargetObjectFile.h Tue May 26 05:19:18 2015
@@ -41,6 +41,8 @@ class MipsTargetMachine;
MCSection *getSectionForConstant(SectionKind Kind,
const Constant *C) const override;
+
+ unsigned SelectMipsTTypeEncoding() const override;
};
} // end namespace llvm
Modified: llvm/trunk/test/CodeGen/Mips/ehframe-indirect.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Mips/ehframe-indirect.ll?rev=238190&r1=238189&r2=238190&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/Mips/ehframe-indirect.ll (original)
+++ llvm/trunk/test/CodeGen/Mips/ehframe-indirect.ll Tue May 26 05:19:18 2015
@@ -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
+
+ at _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", at progbits,DW.ref.__gxx_personality_v0,comdat
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