From 4491d0d337a42f34cf5f51a7324ee6e8af8eb5c2 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Thu, 26 Feb 2015 23:55:11 +0000
Subject: [PATCH] Put jump tables in distinct sections if -ffunction-sections
 is used.

A small regression in r230411 was that we were basing the decision on
-fdata-sections.

llvm-svn: 230707
---
 .../CodeGen/TargetLoweringObjectFileImpl.cpp  | 48 +++++++++++--------
 llvm/test/CodeGen/X86/global-sections.ll      |  6 +++
 2 files changed, 34 insertions(+), 20 deletions(-)

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index c1b34f7f55fd..cb4d3e557cb0 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -244,22 +244,9 @@ static StringRef getSectionPrefixForGlobal(SectionKind Kind) {
   return ".data.rel.ro";
 }
 
-const MCSection *TargetLoweringObjectFileELF::
-SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
-                       Mangler &Mang, const TargetMachine &TM) const {
-  unsigned Flags = getELFSectionFlags(Kind);
-
-  // If we have -ffunction-section or -fdata-section then we should emit the
-  // global value to a uniqued section specifically for it.
-  bool EmitUniqueSection = false;
-  if (!(Flags & ELF::SHF_MERGE) && !Kind.isCommon()) {
-    if (Kind.isText())
-      EmitUniqueSection = TM.getFunctionSections();
-    else
-      EmitUniqueSection = TM.getDataSections();
-  }
-  EmitUniqueSection |= GV->hasComdat();
-
+static const MCSectionELF *selectELFSectionForGlobal(
+    MCContext &Ctx, const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
+    const TargetMachine &TM, bool EmitUniqueSection, unsigned Flags) {
   unsigned EntrySize = 0;
   if (Kind.isMergeableCString()) {
     if (Kind.isMergeable2ByteCString()) {
@@ -309,9 +296,29 @@ SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
     Name.push_back('.');
     TM.getNameWithPrefix(Name, GV, Mang, true);
   }
-  return getContext().getELFSection(Name, getELFSectionType(Name, Kind), Flags,
-                                    EntrySize, Group,
-                                    EmitUniqueSection && !UniqueSectionNames);
+  return Ctx.getELFSection(Name, getELFSectionType(Name, Kind), Flags,
+                           EntrySize, Group,
+                           EmitUniqueSection && !UniqueSectionNames);
+}
+
+const MCSection *TargetLoweringObjectFileELF::SelectSectionForGlobal(
+    const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
+    const TargetMachine &TM) const {
+  unsigned Flags = getELFSectionFlags(Kind);
+
+  // If we have -ffunction-section or -fdata-section then we should emit the
+  // global value to a uniqued section specifically for it.
+  bool EmitUniqueSection = false;
+  if (!(Flags & ELF::SHF_MERGE) && !Kind.isCommon()) {
+    if (Kind.isText())
+      EmitUniqueSection = TM.getFunctionSections();
+    else
+      EmitUniqueSection = TM.getDataSections();
+  }
+  EmitUniqueSection |= GV->hasComdat();
+
+  return selectELFSectionForGlobal(getContext(), GV, Kind, Mang, TM,
+                                   EmitUniqueSection, Flags);
 }
 
 const MCSection *TargetLoweringObjectFileELF::getSectionForJumpTable(
@@ -323,7 +330,8 @@ const MCSection *TargetLoweringObjectFileELF::getSectionForJumpTable(
   if (!EmitUniqueSection)
     return ReadOnlySection;
 
-  return SelectSectionForGlobal(&F, SectionKind::getReadOnly(), Mang, TM);
+  return selectELFSectionForGlobal(getContext(), &F, SectionKind::getReadOnly(),
+                                   Mang, TM, EmitUniqueSection, ELF::SHF_ALLOC);
 }
 
 bool TargetLoweringObjectFileELF::shouldPutJumpTableInFunctionSection(
diff --git a/llvm/test/CodeGen/X86/global-sections.ll b/llvm/test/CodeGen/X86/global-sections.ll
index c2f4b65ffefb..4ee835345c7e 100644
--- a/llvm/test/CodeGen/X86/global-sections.ll
+++ b/llvm/test/CodeGen/X86/global-sections.ll
@@ -3,6 +3,7 @@
 ; 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=i386-unknown-linux-gnu -function-sections | FileCheck %s -check-prefix=LINUX-FUNC-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
 
@@ -42,6 +43,11 @@ bb5:
 ; LINUX-SECTIONS-NEXT: .cfi_endproc
 ; LINUX-SECTIONS-NEXT: .section        .rodata.F2,"a",@progbits
 
+; LINUX-FUNC-SECTIONS: .section        .text.F2,"ax",@progbits
+; LINUX-FUNC-SECTIONS: .size   F2,
+; LINUX-FUNC-SECTIONS-NEXT: .cfi_endproc
+; LINUX-FUNC-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