Do not use named md nodes to track variables that are completely optimized. This does not scale while doing LTO with debug info. New approach is to include list of variables in the subprogram info directly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138145 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 0a284fe..ad16ac1 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -667,31 +667,24 @@
         if (ProcessedSPNodes.count(SP) != 0) continue;
         if (!SP.Verify()) continue;
         if (!SP.isDefinition()) continue;
-        StringRef FName = SP.getLinkageName();
-        if (FName.empty())
-          FName = SP.getName();
-        NamedMDNode *NMD = getFnSpecificMDNode(*(MMI->getModule()), FName);
-        if (!NMD) continue;
-        unsigned E = NMD->getNumOperands();
-        if (!E) continue;
+        DIArray Variables = SP.getVariables();
+        if (Variables.getNumElements() == 0) continue;
+
         LexicalScope *Scope = 
           new LexicalScope(NULL, DIDescriptor(SP), NULL, false);
         DeadFnScopeMap[SP] = Scope;
         
         // Construct subprogram DIE and add variables DIEs.
-        SmallVector<DbgVariable, 8> Variables;
-        for (unsigned I = 0; I != E; ++I) {
-          DIVariable DV(NMD->getOperand(I));
-          if (!DV.Verify()) continue;
-          Variables.push_back(DbgVariable(DV, NULL));
-        }
         CompileUnit *SPCU = CUMap.lookup(TheCU);
         assert (SPCU && "Unable to find Compile Unit!");
         constructSubprogramDIE(SPCU, SP);
         DIE *ScopeDIE = SPCU->getDIE(SP);
-        for (unsigned i = 0, N = Variables.size(); i < N; ++i) {
+        for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
+          DIVariable DV(Variables.getElement(vi));
+          if (!DV.Verify()) continue;
+          DbgVariable *NewVar = new DbgVariable(DV, NULL);
           if (DIE *VariableDIE = 
-              SPCU->constructVariableDIE(&Variables[i], Scope->isAbstractScope()))
+              SPCU->constructVariableDIE(NewVar, Scope->isAbstractScope()))
             ScopeDIE->addChild(VariableDIE);
         }
       }
@@ -977,15 +970,14 @@
   }
 
   // Collect info for variables that were optimized out.
-  const Function *F = MF->getFunction();
-  if (NamedMDNode *NMD = getFnSpecificMDNode(*(F->getParent()), F->getName())) {
-    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
-      DIVariable DV(cast<MDNode>(NMD->getOperand(i)));
-      if (!DV || !Processed.insert(DV))
-        continue;
-      if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext()))
-        addScopeVariable(Scope, new DbgVariable(DV, NULL));
-    }
+  LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
+  DIArray Variables = DISubprogram(FnScope->getScopeNode()).getVariables();
+  for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
+    DIVariable DV(Variables.getElement(i));
+    if (!DV || !DV.Verify() || !Processed.insert(DV))
+      continue;
+    if (LexicalScope *Scope = LScopes.findLexicalScope(DV.getContext()))
+      addScopeVariable(Scope, new DbgVariable(DV, NULL));
   }
 }
 
@@ -1320,18 +1312,13 @@
     DISubprogram SP(AScope->getScopeNode());
     if (SP.Verify()) {
       // Collect info for variables that were optimized out.
-      StringRef FName = SP.getLinkageName();
-      if (FName.empty())
-        FName = SP.getName();
-      if (NamedMDNode *NMD = 
-          getFnSpecificMDNode(*(MF->getFunction()->getParent()), FName)) {
-        for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
-          DIVariable DV(cast<MDNode>(NMD->getOperand(i)));
-          if (!DV || !ProcessedVars.insert(DV))
-            continue;
-          if (LexicalScope *Scope = LScopes.findAbstractScope(DV.getContext()))
-            addScopeVariable(Scope, new DbgVariable(DV, NULL));
-        }
+      DIArray Variables = SP.getVariables();
+      for (unsigned i = 0, e = Variables.getNumElements(); i != e; ++i) {
+        DIVariable DV(Variables.getElement(i));
+        if (!DV || !DV.Verify() || !ProcessedVars.insert(DV))
+          continue;
+        if (LexicalScope *Scope = LScopes.findAbstractScope(DV.getContext()))
+          addScopeVariable(Scope, new DbgVariable(DV, NULL));
       }
     }
     if (ProcessedSPNodes.count(AScope->getScopeNode()) == 0)