[llvm] r228937 - Put each jump table in an independent section if the function is too.
Rafael Espindola
rafael.espindola at gmail.com
Thu Feb 12 09:16:46 PST 2015
Author: rafael
Date: Thu Feb 12 11:16:46 2015
New Revision: 228937
URL: http://llvm.org/viewvc/llvm-project?rev=228937&view=rev
Log:
Put each jump table in an independent section if the function is too.
This allows the linker to GC both, fixing pr22557.
Modified:
llvm/trunk/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
llvm/trunk/include/llvm/Target/TargetLoweringObjectFile.h
llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp
llvm/trunk/test/CodeGen/X86/global-sections-comdat.ll
llvm/trunk/test/CodeGen/X86/global-sections.ll
Modified: llvm/trunk/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h?rev=228937&r1=228936&r2=228937&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h (original)
+++ llvm/trunk/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h Thu Feb 12 11:16:46 2015
@@ -56,6 +56,10 @@ public:
SectionKind Kind, Mangler &Mang,
const TargetMachine &TM) const override;
+ const MCSection *
+ getSectionForJumpTable(const Function &F, Mangler &Mang,
+ const TargetMachine &TM) const override;
+
/// Return an MCExpr to use for a reference to the specified type info global
/// variable from exception handling information.
const MCExpr *
Modified: llvm/trunk/include/llvm/Target/TargetLoweringObjectFile.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetLoweringObjectFile.h?rev=228937&r1=228936&r2=228937&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Target/TargetLoweringObjectFile.h (original)
+++ llvm/trunk/include/llvm/Target/TargetLoweringObjectFile.h Thu Feb 12 11:16:46 2015
@@ -94,6 +94,10 @@ public:
return SectionForGlobal(GV, getKindForGlobal(GV, TM), Mang, TM);
}
+ virtual const MCSection *
+ getSectionForJumpTable(const Function &F, Mangler &Mang,
+ const TargetMachine &TM) 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.
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp?rev=228937&r1=228936&r2=228937&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp Thu Feb 12 11:16:46 2015
@@ -1177,6 +1177,7 @@ void AsmPrinter::EmitJumpTableInfo() {
// Pick the directive to use to print the jump table entries, and switch to
// the appropriate section.
const Function *F = MF->getFunction();
+ const TargetLoweringObjectFile &TLOF = getObjFileLowering();
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.
@@ -1187,13 +1188,11 @@ void AsmPrinter::EmitJumpTableInfo() {
// FIXME: this isn't the right predicate, should be based on the MCSection
// for the function.
F->isWeakForLinker()) {
- OutStreamer.SwitchSection(
- getObjFileLowering().SectionForGlobal(F, *Mang, TM));
+ OutStreamer.SwitchSection(TLOF.SectionForGlobal(F, *Mang, TM));
} else {
// Otherwise, drop it in the readonly section.
const MCSection *ReadOnlySection =
- getObjFileLowering().getSectionForConstant(SectionKind::getReadOnly(),
- /*C=*/nullptr);
+ TLOF.getSectionForJumpTable(*F, *Mang, TM);
OutStreamer.SwitchSection(ReadOnlySection);
JTInDiffSection = true;
}
Modified: llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp?rev=228937&r1=228936&r2=228937&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp (original)
+++ llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp Thu Feb 12 11:16:46 2015
@@ -334,6 +334,28 @@ SelectSectionForGlobal(const GlobalValue
return DataRelROSection;
}
+const MCSection *TargetLoweringObjectFileELF::getSectionForJumpTable(
+ const Function &F, Mangler &Mang, const TargetMachine &TM) const {
+ // If the function can be removed, produce a unique section so that
+ // the table doesn't prevent the removal.
+ const Comdat *C = F.getComdat();
+ bool EmitUniqueSection = TM.getFunctionSections() || C;
+ if (!EmitUniqueSection)
+ return ReadOnlySection;
+
+ SmallString<128> Name(".rodata.");
+ TM.getNameWithPrefix(Name, &F, Mang, true);
+
+ unsigned Flags = ELF::SHF_ALLOC;
+ StringRef Group = "";
+ if (C) {
+ Flags |= ELF::SHF_GROUP;
+ Group = C->getName();
+ }
+
+ return getContext().getELFSection(Name, ELF::SHT_PROGBITS, Flags, 0, Group);
+}
+
/// getSectionForConstant - Given a mergeable constant with the
/// specified size and relocation information, return a section that it
/// should be placed in.
Modified: llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp?rev=228937&r1=228936&r2=228937&view=diff
==============================================================================
--- llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp (original)
+++ llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp Thu Feb 12 11:16:46 2015
@@ -270,6 +270,11 @@ SectionForGlobal(const GlobalValue *GV,
return SelectSectionForGlobal(GV, Kind, Mang, TM);
}
+const MCSection *TargetLoweringObjectFile::getSectionForJumpTable(
+ const Function &F, Mangler &Mang, const TargetMachine &TM) const {
+ return getSectionForConstant(SectionKind::getReadOnly(), /*C=*/nullptr);
+}
+
/// getSectionForConstant - Given a mergable constant with the
/// specified size and relocation information, return a section that it
/// should be placed in.
Modified: llvm/trunk/test/CodeGen/X86/global-sections-comdat.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/global-sections-comdat.ll?rev=228937&r1=228936&r2=228937&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/global-sections-comdat.ll (original)
+++ llvm/trunk/test/CodeGen/X86/global-sections-comdat.ll Thu Feb 12 11:16:46 2015
@@ -1,5 +1,36 @@
; RUN: llc < %s -mtriple=i386-unknown-linux | FileCheck %s -check-prefix=LINUX
-; RUN: llc < %s -mtriple=i386-unknown-linux -data-sections | FileCheck %s -check-prefix=LINUX-SECTIONS
+; RUN: llc < %s -mtriple=i386-unknown-linux -data-sections -function-sections | FileCheck %s -check-prefix=LINUX-SECTIONS
+
+$F1 = comdat any
+define void @F1(i32 %y) comdat {
+bb0:
+switch i32 %y, label %bb5 [
+ i32 1, label %bb1
+ i32 2, label %bb2
+ i32 3, label %bb3
+ i32 4, label %bb4
+ ]
+bb1:
+ ret void
+bb2:
+ ret void
+bb3:
+ ret void
+bb4:
+ ret void
+bb5:
+ ret void
+}
+
+; LINUX: .section .text.F1,"axG", at progbits,F1,comdat
+; LINUX: .size F1,
+; LINUX-NEXT: .cfi_endproc
+; LINUX-NEXT: .section .rodata.F1,"aG", at progbits,F1,comdat
+
+; LINUX-SECTIONS: .section .text.F1,"axG", at progbits,F1,comdat
+; LINUX-SECTIONS: .size F1,
+; LINUX-SECTIONS-NEXT: .cfi_endproc
+; LINUX-SECTIONS-NEXT: .section .rodata.F1,"aG", at progbits,F1,comdat
$G16 = comdat any
@G16 = unnamed_addr constant i32 42, comdat
Modified: llvm/trunk/test/CodeGen/X86/global-sections.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/global-sections.ll?rev=228937&r1=228936&r2=228937&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/global-sections.ll (original)
+++ llvm/trunk/test/CodeGen/X86/global-sections.ll Thu Feb 12 11:16:46 2015
@@ -2,7 +2,7 @@
; RUN: llc < %s -mtriple=i386-apple-darwin9.7 | FileCheck %s -check-prefix=DARWIN
; 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 | FileCheck %s -check-prefix=LINUX-SECTIONS
+; RUN: llc < %s -mtriple=i386-unknown-linux-gnu -data-sections -function-sections | FileCheck %s -check-prefix=LINUX-SECTIONS
; RUN: llc < %s -mtriple=i686-pc-win32 -data-sections -function-sections | FileCheck %s -check-prefix=WIN32-SECTIONS
define void @F1() {
@@ -12,6 +12,35 @@ define void @F1() {
; WIN32-SECTIONS: .section .text,"xr",one_only,_F1
; WIN32-SECTIONS: .globl _F1
+define void @F2(i32 %y) {
+bb0:
+switch i32 %y, label %bb5 [
+ i32 1, label %bb1
+ i32 2, label %bb2
+ i32 3, label %bb3
+ i32 4, label %bb4
+ ]
+bb1:
+ ret void
+bb2:
+ ret void
+bb3:
+ ret void
+bb4:
+ ret void
+bb5:
+ ret void
+}
+
+; LINUX: .size F2,
+; LINUX-NEX: .cfi_endproc
+; LINUX-NEX: .section .rodata,"a", at progbits
+
+; LINUX-SECTIONS: .section .text.F2,"ax", at progbits
+; LINUX-SECTIONS: .size F2,
+; LINUX-SECTIONS-NEXT: .cfi_endproc
+; LINUX-SECTIONS-NEXT: .section .rodata.F2,"a", at progbits
+
; int G1;
@G1 = common global i32 0
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