DebugInfo: New metadata representation for global variables.

This patch reverses the edge from DIGlobalVariable to GlobalVariable.
This will allow us to more easily preserve debug info metadata when
manipulating global variables.

Fixes PR30362. A program for upgrading test cases is attached to that
bug.

Differential Revision: http://reviews.llvm.org/D20147

llvm-svn: 281284

1 files changed, 9 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 307782245a6..d9c7c2bea9e 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -477,12 +477,20 @@ void DwarfDebug::beginModule() {
   MMI->setDebugInfoAvailability(NumDebugCUs > 0);
   SingleCU = NumDebugCUs == 1;
 
+  DenseMap<DIGlobalVariable *, const GlobalVariable *> GVMap;
+  for (const GlobalVariable &Global : M->globals()) {
+    SmallVector<DIGlobalVariable *, 1> GVs;
+    Global.getDebugInfo(GVs);
+    for (auto &GV : GVs)
+      GVMap[GV] = &Global;
+  }
+
   for (DICompileUnit *CUNode : M->debug_compile_units()) {
     DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
     for (auto *IE : CUNode->getImportedEntities())
       CU.addImportedEntity(IE);
     for (auto *GV : CUNode->getGlobalVariables())
-      CU.getOrCreateGlobalVariableDIE(GV);
+      CU.getOrCreateGlobalVariableDIE(GV, GVMap.lookup(GV));
     for (auto *Ty : CUNode->getEnumTypes()) {
       // The enum types array by design contains pointers to
       // MDNodes rather than DIRefs. Unique them here.