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Revert "On ELF, put PIC jump tables in a non executable section." 

This reverts commit r228939.

The commit broke something in the output of exception handling tables on
darwin x86-64.

llvm-svn: 229203
This commit is contained in:
Matthias Braun 2015-02-14 01:16:54 +00:00
parent 2c79ad974c
commit 33cc10724d
6 changed files with 13 additions and 41 deletions
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3
llvm/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
View File

@ -60,9 +60,6 @@ public:
getSectionForJumpTable(const Function &F, Mangler &Mang,
const TargetMachine &TM) const override;
bool shouldPutJumpTableInFunctionSection(bool UsesLabelDifference,
const Function &F) const override;
/// Return an MCExpr to use for a reference to the specified type info global
/// variable from exception handling information.
const MCExpr *

3
llvm/include/llvm/Target/TargetLoweringObjectFile.h
View File

@ -98,9 +98,6 @@ public:
getSectionForJumpTable(const Function &F, Mangler &Mang,
const TargetMachine &TM) const;
virtual bool shouldPutJumpTableInFunctionSection(bool UsesLabelDifference,
const Function &F) const;
/// Targets should implement this method to assign a section to globals with
/// an explicit section specfied. The implementation of this method can
/// assume that GV->hasSection() is true.

17
llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
View File

@ -1178,14 +1178,23 @@ void AsmPrinter::EmitJumpTableInfo() {
// the appropriate section.
const Function *F = MF->getFunction();
const TargetLoweringObjectFile &TLOF = getObjFileLowering();
bool JTInDiffSection = !TLOF.shouldPutJumpTableInFunctionSection(
MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32,
*F);
if (JTInDiffSection) {
bool JTInDiffSection = false;
if (// In PIC mode, we need to emit the jump table to the same section as the
// function body itself, otherwise the label differences won't make sense.
// FIXME: Need a better predicate for this: what about custom entries?
MJTI->getEntryKind() == MachineJumpTableInfo::EK_LabelDifference32 ||
// We should also do if the section name is NULL or function is declared
// in discardable section
// FIXME: this isn't the right predicate, should be based on the MCSection
// for the function.
F->isWeakForLinker()) {
OutStreamer.SwitchSection(TLOF.SectionForGlobal(F, *Mang, TM));
} else {
// Otherwise, drop it in the readonly section.
const MCSection *ReadOnlySection =
TLOF.getSectionForJumpTable(*F, *Mang, TM);
OutStreamer.SwitchSection(ReadOnlySection);
JTInDiffSection = true;
}
EmitAlignment(Log2_32(

7
llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
View File

@ -356,13 +356,6 @@ const MCSection *TargetLoweringObjectFileELF::getSectionForJumpTable(
return getContext().getELFSection(Name, ELF::SHT_PROGBITS, Flags, 0, Group);
}
bool TargetLoweringObjectFileELF::shouldPutJumpTableInFunctionSection(
bool UsesLabelDifference, const Function &F) const {
// We can always create relative relocations, so use another section
// that can be marked non-executable.
return false;
}
/// getSectionForConstant - Given a mergeable constant with the
/// specified size and relocation information, return a section that it
/// should be placed in.

18
llvm/lib/Target/TargetLoweringObjectFile.cpp
View File

@ -275,24 +275,6 @@ const MCSection *TargetLoweringObjectFile::getSectionForJumpTable(
return getSectionForConstant(SectionKind::getReadOnly(), /*C=*/nullptr);
}
bool TargetLoweringObjectFile::shouldPutJumpTableInFunctionSection(
bool UsesLabelDifference, const Function &F) const {
// In PIC mode, we need to emit the jump table to the same section as the
// function body itself, otherwise the label differences won't make sense.
// FIXME: Need a better predicate for this: what about custom entries?
if (UsesLabelDifference)
return true;
// We should also do if the section name is NULL or function is declared
// in discardable section
// FIXME: this isn't the right predicate, should be based on the MCSection
// for the function.
if (F.isWeakForLinker())
return true;
return false;
}
/// getSectionForConstant - Given a mergable constant with the
/// specified size and relocation information, return a section that it
/// should be placed in.

6
llvm/test/CodeGen/X86/global-sections.ll
View File

@ -3,7 +3,6 @@
; RUN: llc < %s -mtriple=i386-apple-darwin10 -relocation-model=static | FileCheck %s -check-prefix=DARWIN-STATIC
; RUN: llc < %s -mtriple=x86_64-apple-darwin10 | FileCheck %s -check-prefix=DARWIN64
; RUN: llc < %s -mtriple=i386-unknown-linux-gnu -data-sections -function-sections | FileCheck %s -check-prefix=LINUX-SECTIONS
; RUN: llc < %s -mtriple=x86_64-pc-linux -data-sections -function-sections -relocation-model=pic | FileCheck %s -check-prefix=LINUX-SECTIONS-PIC
; RUN: llc < %s -mtriple=i686-pc-win32 -data-sections -function-sections | FileCheck %s -check-prefix=WIN32-SECTIONS
define void @F1() {
@ -42,11 +41,6 @@ bb5:
; LINUX-SECTIONS-NEXT: .cfi_endproc
; LINUX-SECTIONS-NEXT: .section .rodata.F2,"a",@progbits
; LINUX-SECTIONS-PIC: .section .text.F2,"ax",@progbits
; LINUX-SECTIONS-PIC: .size F2,
; LINUX-SECTIONS-PIC-NEXT: .cfi_endproc
; LINUX-SECTIONS-PIC-NEXT: .section .rodata.F2,"a",@progbits
; int G1;
@G1 = common global i32 0