[CodeGen/Dwarf] Make debug_names compatible with split-dwarf

Summary:
Previously we crashed for the combination of the two features because we
tried to reference the dwo CU from the main object file. The fix
consists of two items:
- reference the skeleton CU from the name index (the consumer is
  expected to use the skeleton CU to find the real data).
- use the main object file string pool for the strings in the index

Reviewers: JDevlieghere, aprantl, dblaikie

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D45566

llvm-svn: 330249

1 files changed, 3 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/AccelTable.cpp b/llvm/lib/CodeGen/AsmPrinter/AccelTable.cpp
index 1107e02..a1ae137 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AccelTable.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AccelTable.cpp
@@ -416,7 +416,9 @@ void Dwarf5AccelTableEmitter::emitCUList() const {
   for (const auto &CU : enumerate(CompUnits)) {
     assert(CU.index() == CU.value()->getUniqueID());
     Asm->OutStreamer->AddComment("Compilation unit " + Twine(CU.index()));
-    Asm->emitDwarfSymbolReference(CU.value()->getLabelBegin());
+    const DwarfCompileUnit *MainCU =
+        DD.useSplitDwarf() ? CU.value()->getSkeleton() : CU.value().get();
+    Asm->emitDwarfSymbolReference(MainCU->getLabelBegin());
   }
 }