There is only one current section.

Both MCStreamer and MCObjectStreamer were maintaining a current section
variable and they were slightly out of sync. I don't think this was observable,
but was inefficient and error prone.

Changing this requires a few cascading changes:

* SwitchSection has to call ChangeSection earlier for ChangeSection to see
  the old section.
* With that change, ChangeSection cannot call EmitLabel, since during
  ChangeSection we are still in the old section.
* When the object streamer requires a begin label, just reused the existing
  generic support for begin labels instead of calling EmitLabel directly.

llvm-svn: 238357

1 files changed, 7 insertions, 4 deletions

diff --git a/llvm/lib/MC/MCELFStreamer.cpp b/llvm/lib/MC/MCELFStreamer.cpp
index 653a1d2..aa818f9 100644
--- a/llvm/lib/MC/MCELFStreamer.cpp
+++ b/llvm/lib/MC/MCELFStreamer.cpp
@@ -159,11 +159,14 @@ void MCELFStreamer::ChangeSection(MCSection *Section,
     Asm.getOrCreateSymbolData(*Grp);
 
   this->MCObjectStreamer::ChangeSection(Section, Subsection);
-  MCSymbol *SectionSymbol = getContext().getOrCreateSectionSymbol(*SectionELF);
-  if (SectionSymbol->isUndefined()) {
-    EmitLabel(SectionSymbol);
-    MCELF::SetType(Asm.getSymbolData(*SectionSymbol), ELF::STT_SECTION);
+  MCContext &Ctx = getContext();
+  MCSymbol *Begin = Section->getBeginSymbol();
+  if (!Begin) {
+    Begin = Ctx.getOrCreateSectionSymbol(*SectionELF);
+    Section->setBeginSymbol(Begin);
   }
+  if (Begin->isUndefined())
+    MCELF::SetType(Asm.getOrCreateSymbolData(*Begin), ELF::STT_SECTION);
 }
 
 void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {