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

1 files changed, 82 insertions, 91 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 45e0aaa..d096c0b 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();