Until now all debug info MDNodes referred to a root MDNode, a compile unit. This simplified handling of these needs in dwarf writer. However, one side effect of this is that during link time optimization all these MDNodes are _not_ uniqued. In other words there will be N number of MDNodes describing "int", "char" and all other types, which would suddenly grow when each object file starts using libraries like STL.

MDNodes graph structure such that compiler unit keeps track of important MDNodes and update dwarf writer to process mdnodes top-down instead of bottom up.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137778 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 96 insertions, 99 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 3df6c80ae4..f337d18989 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -577,7 +577,10 @@ void CompileUnit::addToContextOwner(DIE *Die, DIDescriptor Context) {
 
 /// getOrCreateTypeDIE - Find existing DIE or create new DIE for the
 /// given DIType.
-DIE *CompileUnit::getOrCreateTypeDIE(DIType Ty) {
+DIE *CompileUnit::getOrCreateTypeDIE(const MDNode *TyNode) {
+  DIType Ty(TyNode);
+  if (!Ty.Verify())
+    return NULL;
   DIE *TyDIE = getDIE(Ty);
   if (TyDIE)
     return TyDIE;
@@ -629,7 +632,8 @@ void CompileUnit::addType(DIE *Entity, DIType Ty) {
 void CompileUnit::addGlobalType(DIType Ty) {
   DIDescriptor Context = Ty.getContext();
   if (Ty.isCompositeType() && !Ty.getName().empty() && !Ty.isForwardDecl() 
-      && (Context.isCompileUnit() || Context.isFile() || Context.isNameSpace()))
+      && (!Context || Context.isCompileUnit() || Context.isFile() 
+          || Context.isNameSpace()))
     if (DIEEntry *Entry = getDIEEntry(Ty))
       GlobalTypes[Ty.getName()] = Entry->getEntry();
 }
@@ -1358,7 +1362,7 @@ DIE *CompileUnit::createMemberDIE(DIDerivedType DT) {
     addUInt(MemberDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_flag,
             dwarf::DW_ACCESS_private);
   // Otherwise C++ member and base classes are considered public.
-  else if (DT.getCompileUnit().getLanguage() == dwarf::DW_LANG_C_plus_plus)
+  else 
     addUInt(MemberDie, dwarf::DW_AT_accessibility, dwarf::DW_FORM_flag,
             dwarf::DW_ACCESS_public);
   if (DT.isVirtual())
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
index 5a155b42a3..785926579f 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
@@ -236,7 +236,7 @@ public:
 
   /// getOrCreateTypeDIE - Find existing DIE or create new DIE for the
   /// given DIType.
-  DIE *getOrCreateTypeDIE(DIType Ty);
+  DIE *getOrCreateTypeDIE(const MDNode *N);
 
   /// getOrCreateTemplateTypeParameterDIE - Find existing DIE or create new DIE 
   /// for the given DITemplateTypeParameter.
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 45e0aaa501..d096c0b9aa 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -465,7 +465,7 @@ unsigned DwarfDebug::GetOrCreateSourceID(StringRef FileName,
 
 /// constructCompileUnit - Create new CompileUnit for the given
 /// metadata node with tag DW_TAG_compile_unit.
-void DwarfDebug::constructCompileUnit(const MDNode *N) {
+CompileUnit *DwarfDebug::constructCompileUnit(const MDNode *N) {
   DICompileUnit DIUnit(N);
   StringRef FN = DIUnit.getFilename();
   StringRef Dir = DIUnit.getDirectory();
@@ -507,35 +507,7 @@ void DwarfDebug::constructCompileUnit(const MDNode *N) {
   if (!FirstCU)
     FirstCU = NewCU;
   CUMap.insert(std::make_pair(N, NewCU));
-}
-
-/// getCompileUnit - Get CompileUnit DIE.
-CompileUnit *DwarfDebug::getCompileUnit(const MDNode *N) const {
-  assert (N && "Invalid DwarfDebug::getCompileUnit argument!");
-  DIDescriptor D(N);
-  const MDNode *CUNode = NULL;
-  if (D.isCompileUnit())
-    CUNode = N;
-  else if (D.isSubprogram())
-    CUNode = DISubprogram(N).getCompileUnit();
-  else if (D.isType())
-    CUNode = DIType(N).getCompileUnit();
-  else if (D.isGlobalVariable())
-    CUNode = DIGlobalVariable(N).getCompileUnit();
-  else if (D.isVariable())
-    CUNode = DIVariable(N).getCompileUnit();
-  else if (D.isNameSpace())
-    CUNode = DINameSpace(N).getCompileUnit();
-  else if (D.isFile())
-    CUNode = DIFile(N).getCompileUnit();
-  else
-    return FirstCU;
-
-  DenseMap<const MDNode *, CompileUnit *>::const_iterator I
-    = CUMap.find(CUNode);
-  if (I == CUMap.end())
-    return FirstCU;
-  return I->second;
+  return NewCU;
 }
 
 /// constructGlobalVariableDIE - Construct global variable DIE.
@@ -571,22 +543,39 @@ void DwarfDebug::constructSubprogramDIE(CompileUnit *TheCU,
   // Expose as global.
   TheCU->addGlobal(SP.getName(), SubprogramDie);
 
+  SPMap[N] = TheCU;
   return;
 }
 
 /// collectInfoFromNamedMDNodes - Collect debug info from named mdnodes such
 /// as llvm.dbg.enum and llvm.dbg.ty
 void DwarfDebug::collectInfoFromNamedMDNodes(Module *M) {
+  if (NamedMDNode *NMD = M->getNamedMetadata("llvm.dbg.sp"))
+    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
+      const MDNode *N = NMD->getOperand(i);
+      if (CompileUnit *CU = CUMap.lookup(DISubprogram(N).getCompileUnit()))
+        constructSubprogramDIE(CU, N);
+    }
+  
+  if (NamedMDNode *NMD = M->getNamedMetadata("llvm.dbg.gv"))
+    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
+      const MDNode *N = NMD->getOperand(i);
+      if (CompileUnit *CU = CUMap.lookup(DIGlobalVariable(N).getCompileUnit()))
+        constructGlobalVariableDIE(CU, N);
+    }
+  
   if (NamedMDNode *NMD = M->getNamedMetadata("llvm.dbg.enum"))
     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
       DIType Ty(NMD->getOperand(i));
-      getCompileUnit(Ty)->getOrCreateTypeDIE(Ty);
+      if (CompileUnit *CU = CUMap.lookup(Ty.getCompileUnit()))
+        CU->getOrCreateTypeDIE(Ty);
     }
   
   if (NamedMDNode *NMD = M->getNamedMetadata("llvm.dbg.ty"))
     for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
       DIType Ty(NMD->getOperand(i));
-      getCompileUnit(Ty)->getOrCreateTypeDIE(Ty);
+      if (CompileUnit *CU = CUMap.lookup(Ty.getCompileUnit()))
+        CU->getOrCreateTypeDIE(Ty);
     }
 }
 
@@ -617,14 +606,16 @@ bool DwarfDebug::collectLegacyDebugInfo(Module *M) {
   for (DebugInfoFinder::iterator I = DbgFinder.global_variable_begin(),
          E = DbgFinder.global_variable_end(); I != E; ++I) {
     const MDNode *N = *I;
-    constructGlobalVariableDIE(getCompileUnit(N), N);
+    if (CompileUnit *CU = CUMap.lookup(DIGlobalVariable(N).getCompileUnit()))
+      constructGlobalVariableDIE(CU, N);
   }
-  
+    
   // Create DIEs for each subprogram.
   for (DebugInfoFinder::iterator I = DbgFinder.subprogram_begin(),
          E = DbgFinder.subprogram_end(); I != E; ++I) {
     const MDNode *N = *I;
-    constructSubprogramDIE(getCompileUnit(N), N);
+    if (CompileUnit *CU = CUMap.lookup(DISubprogram(N).getCompileUnit()))
+      constructSubprogramDIE(CU, N);
   }
 
   return HasDebugInfo;
@@ -641,29 +632,22 @@ void DwarfDebug::beginModule(Module *M) {
   // module using debug info finder to collect debug info.
   NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
   if (CU_Nodes) {
-
-    NamedMDNode *GV_Nodes = M->getNamedMetadata("llvm.dbg.gv");
-    NamedMDNode *SP_Nodes = M->getNamedMetadata("llvm.dbg.sp");
-    if (!GV_Nodes && !SP_Nodes)
-      // If there are not any global variables or any functions then
-      // there is not any debug info in this module.
-      return;
-
-    for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i)
-      constructCompileUnit(CU_Nodes->getOperand(i));
-
-    if (GV_Nodes)
-      for (unsigned i = 0, e = GV_Nodes->getNumOperands(); i != e; ++i) {
-        const MDNode *N = GV_Nodes->getOperand(i);
-        constructGlobalVariableDIE(getCompileUnit(N), N);
-      }
-
-    if (SP_Nodes)
-      for (unsigned i = 0, e = SP_Nodes->getNumOperands(); i != e; ++i) {
-        const MDNode *N = SP_Nodes->getOperand(i);
-        constructSubprogramDIE(getCompileUnit(N), N);
-      }
-    
+    for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
+      DICompileUnit CUNode(CU_Nodes->getOperand(i));
+      CompileUnit *CU = constructCompileUnit(CUNode);
+      DIArray GVs = CUNode.getGlobalVariables();
+      for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
+        constructGlobalVariableDIE(CU, GVs.getElement(i));
+      DIArray SPs = CUNode.getSubprograms();
+      for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
+        constructSubprogramDIE(CU, SPs.getElement(i));
+      DIArray EnumTypes = CUNode.getEnumTypes();
+      for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i)
+        CU->getOrCreateTypeDIE(EnumTypes.getElement(i));
+      DIArray RetainedTypes = CUNode.getRetainedTypes();
+      for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i)
+        CU->getOrCreateTypeDIE(RetainedTypes.getElement(i));
+    }
   } else if (!collectLegacyDebugInfo(M))
     return;
 
@@ -685,39 +669,44 @@ void DwarfDebug::endModule() {
   if (!FirstCU) return;
   const Module *M = MMI->getModule();
   DenseMap<const MDNode *, LexicalScope *> DeadFnScopeMap;
-  if (NamedMDNode *AllSPs = M->getNamedMetadata("llvm.dbg.sp")) {
-    for (unsigned SI = 0, SE = AllSPs->getNumOperands(); SI != SE; ++SI) {
-      if (ProcessedSPNodes.count(AllSPs->getOperand(SI)) != 0) continue;
-      DISubprogram SP(AllSPs->getOperand(SI));
-      if (!SP.Verify()) continue;
-
-      // Collect info for variables that were optimized out.
-      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;
-      LexicalScope *Scope = new LexicalScope(NULL, DIDescriptor(SP), NULL, 
-                                             false);
-      DeadFnScopeMap[SP] = Scope;
-      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));
-      }
 
-      // Construct subprogram DIE and add variables DIEs.
-      CompileUnit *SPCU = getCompileUnit(SP);
-      constructSubprogramDIE(SPCU, SP);
-      DIE *ScopeDIE = SPCU->getDIE(SP);
-      for (unsigned i = 0, N = Variables.size(); i < N; ++i) {
-        if (DIE *VariableDIE = 
-            SPCU->constructVariableDIE(&Variables[i], Scope->isAbstractScope()))
-          ScopeDIE->addChild(VariableDIE);
+  // Collect info for variables that were optimized out.
+  if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
+    for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
+      DICompileUnit TheCU(CU_Nodes->getOperand(i));
+      DIArray Subprograms = TheCU.getSubprograms();
+      for (unsigned i = 0, e = Subprograms.getNumElements(); i != e; ++i) {
+        DISubprogram SP(Subprograms.getElement(i));
+        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;
+        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) {
+          if (DIE *VariableDIE = 
+              SPCU->constructVariableDIE(&Variables[i], Scope->isAbstractScope()))
+            ScopeDIE->addChild(VariableDIE);
+        }
       }
     }
   }
@@ -784,6 +773,7 @@ void DwarfDebug::endModule() {
 
   // clean up.
   DeleteContainerSeconds(DeadFnScopeMap);
+  SPMap.clear();
   for (DenseMap<const MDNode *, CompileUnit *>::iterator I = CUMap.begin(),
          E = CUMap.end(); I != E; ++I)
     delete I->second;
@@ -1333,7 +1323,8 @@ void DwarfDebug::endFunction(const MachineFunction *MF) {
   collectVariableInfo(MF, ProcessedVars);
   
   LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
-  CompileUnit *TheCU = getCompileUnit(FnScope->getScopeNode());
+  CompileUnit *TheCU = SPMap.lookup(FnScope->getScopeNode());
+  assert (TheCU && "Unable to find compile unit!");
 
   // Construct abstract scopes.
   ArrayRef<LexicalScope *> AList = LScopes.getAbstractScopesList();
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 3c8c683bd0..042d693a9b 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -192,8 +192,13 @@ class DwarfDebug {
   //
 
   CompileUnit *FirstCU;
+
+  /// Maps MDNode with its corresponding CompileUnit.
   DenseMap <const MDNode *, CompileUnit *> CUMap;
 
+  /// Maps subprogram MDNode with its corresponding CompileUnit.
+  DenseMap <const MDNode *, CompileUnit *> SPMap;
+
   /// AbbreviationsSet - Used to uniquely define abbreviations.
   ///
   FoldingSet<DIEAbbrev> AbbreviationsSet;
@@ -410,10 +415,7 @@ private:
 
   /// constructCompileUnit - Create new CompileUnit for the given 
   /// metadata node with tag DW_TAG_compile_unit.
-  void constructCompileUnit(const MDNode *N);
-
-  /// getCompielUnit - Get CompileUnit DIE.
-  CompileUnit *getCompileUnit(const MDNode *N) const;
+  CompileUnit *constructCompileUnit(const MDNode *N);
 
   /// constructGlobalVariableDIE - Construct global variable DIE.
   void constructGlobalVariableDIE(CompileUnit *TheCU, const MDNode *N);