From: David Blaikie <dblaikie@gmail.com>
Date: Wed, 4 Dec 2013 18:12:28 +0000 (+0000)
Subject: DebugInfo: Remove unused start/end labels for the debug_abbrevs section
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=193140b0857b2b8b148647fd13a0fb75398417a5;p=oota-llvm.git

DebugInfo: Remove unused start/end labels for the debug_abbrevs section

Since we always emit only one abbrevation section (shared by all the
compilation units in this module) there's no need for a separate label
at the start of each one (and we weren't using the CU ID anyway, so
there really was only one label). Use the section label instead and drop
the wholely unused debug_abbrev_end label.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196394 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index a7056d6a011..be585dc03e7 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2186,9 +2186,6 @@ void DwarfDebug::emitAbbrevs(const MCSection *Section,
     // Start the debug abbrev section.
     Asm->OutStreamer.SwitchSection(Section);
 
-    MCSymbol *Begin = Asm->GetTempSymbol(Section->getLabelBeginName());
-    Asm->OutStreamer.EmitLabel(Begin);
-
     // For each abbrevation.
     for (unsigned i = 0, N = Abbrevs->size(); i < N; ++i) {
       // Get abbreviation data
@@ -2203,9 +2200,6 @@ void DwarfDebug::emitAbbrevs(const MCSection *Section,
 
     // Mark end of abbreviations.
     Asm->EmitULEB128(0, "EOM(3)");
-
-    MCSymbol *End = Asm->GetTempSymbol(Section->getLabelEndName());
-    Asm->OutStreamer.EmitLabel(End);
   }
 }
 
diff --git a/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index d65862040c5..d3504f8a8f6 100644
--- a/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -1980,8 +1980,10 @@ void Unit::emitHeader(const MCSection *ASection, const MCSymbol *ASectionSym) {
   Asm->OutStreamer.AddComment("DWARF version number");
   Asm->EmitInt16(DD->getDwarfVersion());
   Asm->OutStreamer.AddComment("Offset Into Abbrev. Section");
-  Asm->EmitSectionOffset(Asm->GetTempSymbol(ASection->getLabelBeginName()),
-                         ASectionSym);
+  // We share one abbreviations table across all compilation units so it's
+  // always at the start of the section. Use a relocatable offset where needed
+  // to ensure linking doesn't invalidate that offset.
+  Asm->EmitSectionOffset(ASectionSym, ASectionSym);
   Asm->OutStreamer.AddComment("Address Size (in bytes)");
   Asm->EmitInt8(Asm->getDataLayout().getPointerSize());
 }