Revert "[IR] Remove the DIExpression field from DIGlobalVariable."

This reverts commit 289920 (again).
I forgot to implement a Bitcode upgrade for the case where a DIGlobalVariable
has not DIExpression. Unfortunately it is not possible to safely upgrade
these variables without adding a flag to the bitcode record indicating which
version they are.
My plan of record is to roll the planned follow-up patch that adds a
unit: field to DIGlobalVariable into this patch before recomitting.
This way we only need one Bitcode upgrade for both changes (with a
version flag in the bitcode record to safely distinguish the record
formats).

Sorry for the churn!

llvm-svn: 289982

1 files changed, 11 insertions, 14 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 3f5ef1a..8e17032 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -2181,13 +2181,12 @@ void CodeViewDebug::emitDebugInfoForUDTs(
 }
 
 void CodeViewDebug::emitDebugInfoForGlobals() {
-  DenseMap<const DIGlobalVariableExpression *, const GlobalVariable *>
-      GlobalMap;
+  DenseMap<const DIGlobalVariable *, const GlobalVariable *> GlobalMap;
   for (const GlobalVariable &GV : MMI->getModule()->globals()) {
-    SmallVector<DIGlobalVariableExpression *, 1> GVEs;
-    GV.getDebugInfo(GVEs);
-    for (const auto *GVE : GVEs)
-      GlobalMap[GVE] = &GV;
+    SmallVector<MDNode *, 1> MDs;
+    GV.getMetadata(LLVMContext::MD_dbg, MDs);
+    for (MDNode *MD : MDs)
+      GlobalMap[cast<DIGlobalVariable>(MD)] = &GV;
   }
 
   NamedMDNode *CUs = MMI->getModule()->getNamedMetadata("llvm.dbg.cu");
@@ -2199,15 +2198,14 @@ void CodeViewDebug::emitDebugInfoForGlobals() {
     // it if we have at least one global to emit.
     switchToDebugSectionForSymbol(nullptr);
     MCSymbol *EndLabel = nullptr;
-    for (const auto *GVE : CU->getGlobalVariables()) {
-      if (const auto *GV = GlobalMap.lookup(GVE))
+    for (const DIGlobalVariable *G : CU->getGlobalVariables()) {
+      if (const auto *GV = GlobalMap.lookup(G))
         if (!GV->hasComdat() && !GV->isDeclarationForLinker()) {
           if (!EndLabel) {
             OS.AddComment("Symbol subsection for globals");
             EndLabel = beginCVSubsection(ModuleSubstreamKind::Symbols);
           }
-          // FIXME: emitDebugInfoForGlobal() doesn't handle DIExpressions.
-          emitDebugInfoForGlobal(GVE->getVariable(), GV, Asm->getSymbol(GV));
+          emitDebugInfoForGlobal(G, GV, Asm->getSymbol(GV));
         }
     }
     if (EndLabel)
@@ -2215,16 +2213,15 @@ void CodeViewDebug::emitDebugInfoForGlobals() {
 
     // Second, emit each global that is in a comdat into its own .debug$S
     // section along with its own symbol substream.
-    for (const auto *GVE : CU->getGlobalVariables()) {
-      if (const auto *GV = GlobalMap.lookup(GVE)) {
+    for (const DIGlobalVariable *G : CU->getGlobalVariables()) {
+      if (const auto *GV = GlobalMap.lookup(G)) {
         if (GV->hasComdat()) {
           MCSymbol *GVSym = Asm->getSymbol(GV);
           OS.AddComment("Symbol subsection for " +
                         Twine(GlobalValue::getRealLinkageName(GV->getName())));
           switchToDebugSectionForSymbol(GVSym);
           EndLabel = beginCVSubsection(ModuleSubstreamKind::Symbols);
-          // FIXME: emitDebugInfoForGlobal() doesn't handle DIExpressions.
-          emitDebugInfoForGlobal(GVE->getVariable(), GV, GVSym);
+          emitDebugInfoForGlobal(G, GV, GVSym);
           endCVSubsection(EndLabel);
         }
       }