Revise debug info machinery to digest nested functions and classes.

A certain GDB testsuite case (local.cc) has a function nested inside a
class nested inside another function.  GCC presents the innermost
function to llvm-convert first.  Heretofore, the debug info mistakenly
placed the inner function at module scope.  This patch walks the GCC
context links and instantiates the outer class and function so the
debug info is properly nested.  Radar 7426545.

llvm-svn: 100530

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -800,12 +800,26 @@ void DwarfDebug::addToContextOwner(DIE *Die, DIDescriptor Context) {
   } else if (Context.isNameSpace()) {
     DIE *ContextDIE = getOrCreateNameSpace(DINameSpace(Context.getNode()));
     ContextDIE->addChild(Die);
+  } else if (Context.isSubprogram()) {
+    DIE *ContextDIE = createSubprogramDIE(DISubprogram(Context.getNode()),
+                                          /*MakeDecl=*/false);
+    ContextDIE->addChild(Die);
   } else if (DIE *ContextDIE = ModuleCU->getDIE(Context.getNode()))
     ContextDIE->addChild(Die);
   else 
     ModuleCU->addDie(Die);
 }
 
+/// isFunctionContext - True if given Context is nested within a function. 
+bool DwarfDebug::isFunctionContext(DIE *context) {
+  if (context == (DIE *)0)
+    return false;
+  if (context->getTag() == dwarf::DW_TAG_subprogram)
+    return true;
+  else
+    return isFunctionContext(context->getParent());
+}
+
 /// getOrCreateTypeDIE - Find existing DIE or create new DIE for the
 /// given DIType.
 DIE *DwarfDebug::getOrCreateTypeDIE(DIType Ty) {
@@ -987,6 +1001,10 @@ void DwarfDebug::constructTypeDIE(DIE &Buffer, DICompositeType CTy) {
     if (DIDescriptor(ContainingType.getNode()).isCompositeType())
       addDIEEntry(&Buffer, dwarf::DW_AT_containing_type, dwarf::DW_FORM_ref4, 
                   getOrCreateTypeDIE(DIType(ContainingType.getNode())));
+    else {
+      DIDescriptor Context = CTy.getContext();
+      addToContextOwner(&Buffer, Context);
+    }
     break;
   }
   default:
@@ -1802,19 +1820,15 @@ void DwarfDebug::constructGlobalVariableDIE(MDNode *N) {
 void DwarfDebug::constructSubprogramDIE(MDNode *N) {
   DISubprogram SP(N);
 
-  // Check for pre-existence.
-  if (ModuleCU->getDIE(N))
-    return;
-
   if (!SP.isDefinition())
     // This is a method declaration which will be handled while constructing
     // class type.
     return;
 
-  DIE *SubprogramDie = createSubprogramDIE(SP);
+  // Check for pre-existence.
-
+  DIE *SubprogramDie = ModuleCU->getDIE(N);
-  // Add to map.
+  if (!SubprogramDie)
-  ModuleCU->insertDIE(N, SubprogramDie);
+    SubprogramDie = createSubprogramDIE(SP);
 
   // Add to context owner.
   addToContextOwner(SubprogramDie, SP.getContext());

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h

@@ -332,6 +332,9 @@ private:
   /// addToContextOwner - Add Die into the list of its context owner's children.
   void addToContextOwner(DIE *Die, DIDescriptor Context);
 
+  /// isFunctionContext - True if given Context is nested within a function. 
+  bool isFunctionContext(DIE *context);
+
   /// addType - Add a new type attribute to the specified entity.
   void addType(DIE *Entity, DIType Ty);
 

llvm/test/FrontendC++/2010-02-17-DbgArtificialArg.cpp

@@ -1,4 +1,4 @@
-// RUN: %llvmgcc -g -S %s -o - | grep DW_TAG_pointer_type |  grep "i32 524303, metadata .., metadata ..., metadata .., i32 ., i64 .., i64 .., i64 0, i32 64, metadata ..."
+// RUN: %llvmgcc -g -S %s -o - | FileCheck %s
 // Here, second to last argument "i32 64" indicates that artificial type is set.                                               
 // Test to artificial attribute attahed to "this" pointer type.
 // Radar 7655792 and 7655002
@@ -10,5 +10,7 @@ public:
 
 int foo() {
   A a;
+  // Matching "i32 64, metadata !<number>} ; [ DW_TAG_pointer_type ]"
+  // CHECK: i32 64, metadata {{![0-9]+\} ; \[ DW_TAG_pointer_type \]}}
   return a.fn1(1);
 }