Revert "Added debug info for localized global variables for inlined scopes. (#7799)" (#8185)

This reverts commit
[450bbe5](450bbe5).

A bug was discovered and we have decided to revert this change in the
6.9 release branch while we work on the fix.

Author: alsepkow

lib/Transforms/Scalar/ScalarReplAggregatesHLSL.cpp

@@ -6498,55 +6498,8 @@ ModulePass *llvm::createSROA_Parameter_HLSL() {
 //===----------------------------------------------------------------------===//
 
 namespace {
-
-struct GVDebugInfoPatchCache {
-  DenseMap<Function *, SetVector<DISubprogram *>> SubprogramsForFunction;
-  DenseSet<DILocation *> Seen;
-  DITypeIdentifierMap EmptyMap;
-
-  void CollectSubprograms(DILocation *Loc, SetVector<DISubprogram *> &Set) {
-    while (Loc) {
-      // This is potentially very expensive. Avoid repeatedly looking for
-      // DISubprogram's
-      if (Seen.count(Loc))
-        return;
-      Seen.insert(Loc);
-      auto *Scope = dyn_cast<DIScope>(Loc->getScope());
-      while (Scope) {
-        if (auto SubP = dyn_cast<DISubprogram>(Scope)) {
-          Set.insert(SubP);
-          break;
-        }
-        Scope = Scope->getScope().resolve(EmptyMap);
-      }
-      Loc = Loc->getInlinedAt();
-    }
-  }
-
-  SetVector<DISubprogram *> &
-  GetSubprogramsForFunction(Function *F, DebugInfoFinder &DbgFinder) {
-    auto It = SubprogramsForFunction.find(F);
-    if (It != SubprogramsForFunction.end())
-      return It->second;
-
-    SetVector<DISubprogram *> &Ret = SubprogramsForFunction[F];
-    for (DISubprogram *SP : DbgFinder.subprograms()) {
-      if (SP->getFunction() == F) {
-        Ret.insert(SP);
-        break;
-      }
-    }
-
-    for (BasicBlock &BB : *F)
-      for (Instruction &I : BB)
-        CollectSubprograms(I.getDebugLoc(), Ret);
-    return Ret;
-  }
-};
-
 class LowerStaticGlobalIntoAlloca : public ModulePass {
   DebugInfoFinder m_DbgFinder;
-  GVDebugInfoPatchCache m_GVDebugInfoCache;
 
 public:
   static char ID; // Pass identification, replacement for typeid
@@ -6734,15 +6687,28 @@ FindGlobalVariableFragment(const DebugInfoFinder &DbgFinder,
 // Create a fake local variable for the GlobalVariable GV that has just been
 // lowered to local Alloca.
 //
-static void PatchDebugInfo(GVDebugInfoPatchCache &Cache,
-                           DebugInfoFinder &DbgFinder, Function *F,
+static void PatchDebugInfo(DebugInfoFinder &DbgFinder, Function *F,
                            GlobalVariable *GV, AllocaInst *AI) {
+  if (!DbgFinder.compile_unit_count())
+    return;
+
+  // Find the subprogram for function
+  DISubprogram *Subprogram = nullptr;
+  for (DISubprogram *SP : DbgFinder.subprograms()) {
+    if (SP->getFunction() == F) {
+      Subprogram = SP;
+      break;
+    }
+  }
+
   DIGlobalVariable *DGV = dxilutil::FindGlobalVariableDebugInfo(GV, DbgFinder);
   if (!DGV)
     return;
 
-  if (!DbgFinder.compile_unit_count())
-    return;
+  DITypeIdentifierMap EmptyMap;
+  DIBuilder DIB(*GV->getParent());
+  DIScope *Scope = Subprogram;
+  DebugLoc Loc = DebugLoc::get(DGV->getLine(), 0, Scope);
 
   // If the variable is a member of another variable, find the offset and size
   bool IsFragment = false;
@@ -6759,30 +6725,20 @@ static void PatchDebugInfo(GVDebugInfoPatchCache &Cache,
   // Subprogram as its scope, so we don't have to make one up for it.
   llvm::dwarf::Tag Tag = llvm::dwarf::Tag::DW_TAG_arg_variable;
 
-  DITypeIdentifierMap EmptyMap;
   DIType *Ty = DGV->getType().resolve(EmptyMap);
   DXASSERT(Ty->getTag() != dwarf::DW_TAG_member,
            "Member type is not allowed for variables.");
+  DILocalVariable *ConvertedLocalVar = DIB.createLocalVariable(
+      Tag, Scope, Name, DGV->getFile(), DGV->getLine(), Ty);
 
-  DIBuilder DIB(*GV->getParent());
-
-  SetVector<DISubprogram *> &Subprograms =
-      Cache.GetSubprogramsForFunction(F, DbgFinder);
-  for (DISubprogram *Subprogram : Subprograms) {
-    DIScope *Scope = Subprogram;
-    DebugLoc Loc = DebugLoc::get(DGV->getLine(), 0, Scope);
-
-    DILocalVariable *ConvertedLocalVar = DIB.createLocalVariable(
-        Tag, Scope, Name, DGV->getFile(), DGV->getLine(), Ty);
-
-    DIExpression *Expr = nullptr;
-    if (IsFragment)
-      Expr = DIB.createBitPieceExpression(OffsetInBits, SizeInBits);
-    else
-      Expr = DIB.createExpression(ArrayRef<int64_t>());
-
-    DIB.insertDeclare(AI, ConvertedLocalVar, Expr, Loc, AI->getNextNode());
+  DIExpression *Expr = nullptr;
+  if (IsFragment) {
+    Expr = DIB.createBitPieceExpression(OffsetInBits, SizeInBits);
+  } else {
+    Expr = DIB.createExpression(ArrayRef<int64_t>());
   }
+
+  DIB.insertDeclare(AI, ConvertedLocalVar, Expr, Loc, AI->getNextNode());
 }
 
 // Collect instructions using GV and the value used by the instruction.
@@ -6860,7 +6816,7 @@ bool LowerStaticGlobalIntoAlloca::lowerStaticGlobalIntoAlloca(
     if (AI->user_empty())
       AI->eraseFromParent();
     else
-      PatchDebugInfo(m_GVDebugInfoCache, m_DbgFinder, F, GV, AI);
+      PatchDebugInfo(m_DbgFinder, F, GV, AI);
   }
 
   GV->removeDeadConstantUsers();