Debug Info: move DIScope::getContext to DwarfDebug.

    
DIScope::getContext is a wrapper function that calls the specific getContext
method on each subclass. When we switch DIType::getContext to return DIScopeRef
instead of DIScope, DIScope::getContext can no longer return a DIScope without
a type identifier map.
    
DIScope::getContext is only used by DwarfDebug, so we move it to DwarfDebug
to have easy access to the type identifier map.

llvm-svn: 190330

3 files changed, 31 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 6ec68834cf2..f9ce5918335 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -913,19 +913,19 @@ void CompileUnit::constructTypeDIE(DIE &Buffer, DIDerivedType DTy) {
 
 /// Return true if the type is appropriately scoped to be contained inside
 /// its own type unit.
-static bool isTypeUnitScoped(DIType Ty) {
+static bool isTypeUnitScoped(DIType Ty, const DwarfDebug *DD) {
   DIScope Parent = Ty.getContext();
   while (Parent) {
     // Don't generate a hash for anything scoped inside a function.
     if (Parent.isSubprogram())
       return false;
-    Parent = Parent.getContext();
+    Parent = DD->getScopeContext(Parent);
   }
   return true;
 }
 
 /// Return true if the type should be split out into a type unit.
-static bool shouldCreateTypeUnit(DICompositeType CTy) {
+static bool shouldCreateTypeUnit(DICompositeType CTy, const DwarfDebug *DD) {
   uint16_t Tag = CTy.getTag();
 
   switch (Tag) {
@@ -936,7 +936,7 @@ static bool shouldCreateTypeUnit(DICompositeType CTy) {
     // If this is a class, structure, union, or enumeration type
     // that is not a declaration, is a type definition, and not scoped
     // inside a function then separate this out as a type unit.
-    if (CTy.isForwardDecl() || !isTypeUnitScoped(CTy))
+    if (CTy.isForwardDecl() || !isTypeUnitScoped(CTy, DD))
       return 0;
     return 1;
   default:
@@ -1138,7 +1138,7 @@ void CompileUnit::constructTypeDIE(DIE &Buffer, DICompositeType CTy) {
   }
   // If this is a type applicable to a type unit it then add it to the
   // list of types we'll compute a hash for later.
-  if (shouldCreateTypeUnit(CTy))
+  if (shouldCreateTypeUnit(CTy, DD))
     DD->addTypeUnitType(&Buffer);
 }
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index bdcb813e227..1cfadc91e03 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2650,3 +2650,26 @@ void DwarfDebug::emitDebugStrDWO() {
 DIScope DwarfDebug::resolve(DIScopeRef SRef) const {
   return SRef.resolve(TypeIdentifierMap);
 }
+
+// If the current node has a parent scope then return that,
+// else return an empty scope.
+DIScope DwarfDebug::getScopeContext(DIScope S) const {
+
+  if (S.isType())
+    return DIType(S).getContext();
+
+  if (S.isSubprogram())
+    return DISubprogram(S).getContext();
+
+  if (S.isLexicalBlock())
+    return DILexicalBlock(S).getContext();
+
+  if (S.isLexicalBlockFile())
+    return DILexicalBlockFile(S).getContext();
+
+  if (S.isNameSpace())
+    return DINameSpace(S).getContext();
+
+  assert((S.isFile() || S.isCompileUnit()) && "Unhandled type of scope.");
+  return DIScope();
+}
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index f8c27d950ec..afac39c5226 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -690,6 +690,9 @@ public:
   /// or another context nested inside a subprogram.
   bool isSubprogramContext(const MDNode *Context);
 
+  /// Gets the parent scope for this scope node or returns a
+  /// default constructed scope.
+  DIScope getScopeContext(DIScope S) const;
 };
 } // End of namespace llvm