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: 228980

1 files changed, 14 insertions, 6 deletions

diff --git a/llvm/lib/MC/MCContext.cpp b/llvm/lib/MC/MCContext.cpp
index 35609893e28..721edd451ee 100644
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/lib/MC/MCContext.cpp
@@ -272,12 +272,13 @@ void MCContext::renameELFSection(const MCSectionELF *Section, StringRef Name) {
 
 const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
                                              unsigned Flags, unsigned EntrySize,
-                                             StringRef Group) {
+                                             StringRef Group, bool Unique) {
   // Do the lookup, if we have a hit, return it.
   auto IterBool = ELFUniquingMap.insert(
       std::make_pair(SectionGroupPair(Section, Group), nullptr));
   auto &Entry = *IterBool.first;
-  if (!IterBool.second) return Entry.second;
+  if (!IterBool.second && !Unique)
+    return Entry.second;
 
   MCSymbol *GroupSym = nullptr;
   if (!Group.empty())
@@ -292,15 +293,22 @@ const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
     Kind = SectionKind::getReadOnly();
 
   MCSectionELF *Result = new (*this)
-      MCSectionELF(CachedName, Type, Flags, Kind, EntrySize, GroupSym);
-  Entry.second = Result;
+      MCSectionELF(CachedName, Type, Flags, Kind, EntrySize, GroupSym, Unique);
+  if (!Unique)
+    Entry.second = Result;
   return Result;
 }
 
+const MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
+                                             unsigned Flags, unsigned EntrySize,
+                                             StringRef Group) {
+  return getELFSection(Section, Type, Flags, EntrySize, Group, false);
+}
+
 const MCSectionELF *MCContext::CreateELFGroupSection() {
   MCSectionELF *Result =
-    new (*this) MCSectionELF(".group", ELF::SHT_GROUP, 0,
-                             SectionKind::getReadOnly(), 4, nullptr);
+      new (*this) MCSectionELF(".group", ELF::SHT_GROUP, 0,
+                               SectionKind::getReadOnly(), 4, nullptr, false);
   return Result;
 }