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

3 files changed, 89 insertions, 50 deletions

diff --git a/lib/Analysis/DIBuilder.cpp b/lib/Analysis/DIBuilder.cpp
index 450412f421..5311d6f10f 100644
--- a/lib/Analysis/DIBuilder.cpp
+++ b/lib/Analysis/DIBuilder.cpp
@@ -43,6 +43,19 @@ void DIBuilder::finalize() {
 
   DIArray SPs = getOrCreateArray(AllSubprograms);
   DIType(TempSubprograms).replaceAllUsesWith(SPs);
+  for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i) {
+    DISubprogram SP(SPs.getElement(i));
+    if (NamedMDNode *NMD = getFnSpecificMDNode(M, SP)) {
+      SmallVector<Value *, 4> Variables;
+      for (unsigned ii = 0, ee = NMD->getNumOperands(); ii != ee; ++ii)
+        Variables.push_back(NMD->getOperand(ii));
+      if (MDNode *Temp = SP.getVariablesNodes()) {
+        DIArray AV = getOrCreateArray(Variables);
+        DIType(Temp).replaceAllUsesWith(AV);
+      }
+      NMD->eraseFromParent();
+    }
+  }
 
   DIArray GVs = getOrCreateArray(AllGVs);
   DIType(TempGVs).replaceAllUsesWith(GVs);
@@ -674,13 +687,7 @@ DIVariable DIBuilder::createLocalVariable(unsigned Tag, DIDescriptor Scope,
     // to preserve variable info in such situation then stash it in a
     // named mdnode.
     DISubprogram Fn(getDISubprogram(Scope));
-    StringRef FName = "fn";
-    if (Fn.getFunction())
-      FName = Fn.getFunction()->getName();
-    char One = '\1';
-    if (FName.startswith(StringRef(&One, 1)))
-      FName = FName.substr(1);
-    NamedMDNode *FnLocals = getOrInsertFnSpecificMDNode(M, FName);
+    NamedMDNode *FnLocals = getOrInsertFnSpecificMDNode(M, Fn);
     FnLocals->addOperand(Node);
   }
   return DIVariable(Node);
@@ -718,6 +725,11 @@ DISubprogram DIBuilder::createFunction(DIDescriptor Context,
                                        Function *Fn,
                                        MDNode *TParams,
                                        MDNode *Decl) {
+  Value *TElts[] = { GetTagConstant(VMContext, DW_TAG_base_type) };
+  MDNode *Temp = MDNode::getTemporary(VMContext, TElts);
+  Value *TVElts[] = { Temp };
+  MDNode *THolder = MDNode::get(VMContext, TVElts);
+
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_subprogram),
     llvm::Constant::getNullValue(Type::getInt32Ty(VMContext)),
@@ -737,7 +749,8 @@ DISubprogram DIBuilder::createFunction(DIDescriptor Context,
     ConstantInt::get(Type::getInt1Ty(VMContext), isOptimized),
     Fn,
     TParams,
-    Decl
+    Decl,
+    THolder
   };
   MDNode *Node = MDNode::get(VMContext, Elts);
 
@@ -760,6 +773,11 @@ DISubprogram DIBuilder::createMethod(DIDescriptor Context,
                                      bool isOptimized,
                                      Function *Fn,
                                      MDNode *TParam) {
+  Value *TElts[] = { GetTagConstant(VMContext, DW_TAG_base_type) };
+  MDNode *Temp = MDNode::getTemporary(VMContext, TElts);
+  Value *TVElts[] = { Temp };
+  MDNode *THolder = MDNode::get(VMContext, TVElts);
+
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_subprogram),
     llvm::Constant::getNullValue(Type::getInt32Ty(VMContext)),
@@ -779,6 +797,8 @@ DISubprogram DIBuilder::createMethod(DIDescriptor Context,
     ConstantInt::get(Type::getInt1Ty(VMContext), isOptimized),
     Fn,
     TParam,
+    llvm::Constant::getNullValue(Type::getInt32Ty(VMContext)),
+    THolder
   };
   MDNode *Node = MDNode::get(VMContext, Elts);
   return DISubprogram(Node);
diff --git a/lib/Analysis/DebugInfo.cpp b/lib/Analysis/DebugInfo.cpp
index e6ce9e4e74..7935fadb2f 100644
--- a/lib/Analysis/DebugInfo.cpp
+++ b/lib/Analysis/DebugInfo.cpp
@@ -512,6 +512,23 @@ unsigned DISubprogram::isOptimized() const {
   return 0;
 }
 
+MDNode *DISubprogram::getVariablesNodes() const {
+  if (!DbgNode || DbgNode->getNumOperands() <= 19)
+    return NULL;
+  if (MDNode *Temp = dyn_cast_or_null<MDNode>(DbgNode->getOperand(19)))
+    return dyn_cast_or_null<MDNode>(Temp->getOperand(0));
+  return NULL;
+}
+
+DIArray DISubprogram::getVariables() const {
+  if (!DbgNode || DbgNode->getNumOperands() <= 19)
+    return DIArray();
+  if (MDNode *T = dyn_cast_or_null<MDNode>(DbgNode->getOperand(19)))
+    if (MDNode *A = dyn_cast_or_null<MDNode>(T->getOperand(0)))
+      return DIArray(A);
+  return DIArray();
+}
+
 StringRef DIScope::getFilename() const {
   if (!DbgNode)
     return StringRef();
@@ -825,19 +842,34 @@ static void fixupObjcLikeName(StringRef Str, SmallVectorImpl<char> &Out) {
 
 /// getFnSpecificMDNode - Return a NameMDNode, if available, that is 
 /// suitable to hold function specific information.
-NamedMDNode *llvm::getFnSpecificMDNode(const Module &M, StringRef FuncName) {
+NamedMDNode *llvm::getFnSpecificMDNode(const Module &M, DISubprogram Fn) {
   SmallString<32> Name = StringRef("llvm.dbg.lv.");
-  fixupObjcLikeName(FuncName, Name);
-
+  StringRef FName = "fn";
+  if (Fn.getFunction())
+    FName = Fn.getFunction()->getName();
+  else
+    FName = Fn.getName();
+  char One = '\1';
+  if (FName.startswith(StringRef(&One, 1)))
+    FName = FName.substr(1);
+  fixupObjcLikeName(FName, Name);
   return M.getNamedMetadata(Name.str());
 }
 
 /// getOrInsertFnSpecificMDNode - Return a NameMDNode that is suitable
 /// to hold function specific information.
-NamedMDNode *llvm::getOrInsertFnSpecificMDNode(Module &M, StringRef FuncName) {
+NamedMDNode *llvm::getOrInsertFnSpecificMDNode(Module &M, DISubprogram Fn) {
   SmallString<32> Name = StringRef("llvm.dbg.lv.");
-  fixupObjcLikeName(FuncName, Name);
-
+  StringRef FName = "fn";
+  if (Fn.getFunction())
+    FName = Fn.getFunction()->getName();
+  else
+    FName = Fn.getName();
+  char One = '\1';
+  if (FName.startswith(StringRef(&One, 1)))
+    FName = FName.substr(1);
+  fixupObjcLikeName(FName, Name);
+  
   return M.getOrInsertNamedMetadata(Name.str());
 }
 
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 0a284fefaa..ad16ac1004 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -667,31 +667,24 @@ void DwarfDebug::endModule() {
         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 @@ DwarfDebug::collectVariableInfo(const MachineFunction *MF,
   }
 
   // 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 @@ void DwarfDebug::endFunction(const MachineFunction *MF) {
     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)