Add r228980 back.

Add support for having multiple sections with the same name and comdat.

Using this in combination with -ffunction-sections allows LLVM to output a .o
file with mulitple sections named .text. This saves space by avoiding long
unique names of the form .text.<C++ mangled name>.

llvm-svn: 229541

1 files changed, 17 insertions, 14 deletions

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 17bd024ad28..07d9576222e 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -228,25 +228,25 @@ const MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal(
 /// DataSections.
 static StringRef getSectionPrefixForGlobal(SectionKind Kind) {
   if (Kind.isText())
-    return ".text.";
+    return ".text";
   if (Kind.isReadOnly())
-    return ".rodata.";
+    return ".rodata";
   if (Kind.isBSS())
-    return ".bss.";
+    return ".bss";
   if (Kind.isThreadData())
-    return ".tdata.";
+    return ".tdata";
   if (Kind.isThreadBSS())
-    return ".tbss.";
+    return ".tbss";
   if (Kind.isDataNoRel())
-    return ".data.";
+    return ".data";
   if (Kind.isDataRelLocal())
-    return ".data.rel.local.";
+    return ".data.rel.local";
   if (Kind.isDataRel())
-    return ".data.rel.";
+    return ".data.rel";
   if (Kind.isReadOnlyWithRelLocal())
-    return ".data.rel.ro.local.";
+    return ".data.rel.ro.local";
   assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
-  return ".data.rel.ro.";
+  return ".data.rel.ro";
 }
 
 const MCSection *TargetLoweringObjectFileELF::
@@ -268,16 +268,19 @@ SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
     StringRef Prefix = getSectionPrefixForGlobal(Kind);
 
     SmallString<128> Name(Prefix);
-    TM.getNameWithPrefix(Name, GV, Mang, true);
-
+    bool UniqueSectionNames = TM.getUniqueSectionNames();
+    if (UniqueSectionNames) {
+      Name.push_back('.');
+      TM.getNameWithPrefix(Name, GV, Mang, true);
+    }
     StringRef Group = "";
     if (const Comdat *C = getELFComdat(GV)) {
       Flags |= ELF::SHF_GROUP;
       Group = C->getName();
     }
 
-    return getContext().getELFSection(
-        Name.str(), getELFSectionType(Name.str(), Kind), Flags, 0, Group);
+    return getContext().getELFSection(Name, getELFSectionType(Name, Kind),
+                                      Flags, 0, Group, !UniqueSectionNames);
   }
 
   if (Kind.isText()) return TextSection;