PR14606: Debug Info for namespace aliases/DW_TAG_imported_module

This resolves the last of the PR14606 failures in the GDB 7.5 test
suite. (but there are still unresolved issues in the imported_decl case
- we need to implement optional/lazy decls for functions & variables
like we already do for types)

llvm-svn: 182329

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -3084,6 +3084,30 @@ void CGDebugInfo::EmitUsingDecl(const UsingDecl &UD) {
         getLineNumber(USD.getLocation()));
 }
 
+llvm::DIImportedEntity
+CGDebugInfo::EmitNamespaceAlias(const NamespaceAliasDecl &NA) {
+  if (CGM.getCodeGenOpts().getDebugInfo() < CodeGenOptions::LimitedDebugInfo)
+    return llvm::DIImportedEntity(0);
+  llvm::WeakVH &VH = NamespaceAliasCache[&NA];
+  if (VH)
+    return llvm::DIImportedEntity(cast<llvm::MDNode>(VH));
+  llvm::DIImportedEntity R(0);
+  if (const NamespaceAliasDecl *Underlying =
+          dyn_cast<NamespaceAliasDecl>(NA.getAliasedNamespace()))
+    // This could cache & dedup here rather than relying on metadata deduping.
+    R = DBuilder.createImportedModule(
+        getCurrentContextDescriptor(cast<Decl>(NA.getDeclContext())),
+        EmitNamespaceAlias(*Underlying), getLineNumber(NA.getLocation()),
+        NA.getName());
+  else
+    R = DBuilder.createImportedModule(
+        getCurrentContextDescriptor(cast<Decl>(NA.getDeclContext())),
+        getOrCreateNameSpace(cast<NamespaceDecl>(NA.getAliasedNamespace())),
+        getLineNumber(NA.getLocation()), NA.getName());
+  VH = R;
+  return R;
+}
+
 /// getOrCreateNamesSpace - Return namespace descriptor for the given
 /// namespace decl.
 llvm::DINameSpace

clang/lib/CodeGen/CGDebugInfo.h

@@ -101,6 +101,7 @@ class CGDebugInfo {
   /// using declarations) that aren't covered by other more specific caches.
   llvm::DenseMap<const Decl *, llvm::WeakVH> DeclCache;
   llvm::DenseMap<const NamespaceDecl *, llvm::WeakVH> NameSpaceCache;
+  llvm::DenseMap<const NamespaceAliasDecl *, llvm::WeakVH> NamespaceAliasCache;
   llvm::DenseMap<const Decl *, llvm::WeakVH> StaticDataMemberCache;
 
   /// Helper functions for getOrCreateType.
@@ -277,6 +278,9 @@ public:
   /// \brief - Emit C++ using declaration.
   void EmitUsingDecl(const UsingDecl &UD);
 
+  /// \brief - Emit C++ namespace alias.
+  llvm::DIImportedEntity EmitNamespaceAlias(const NamespaceAliasDecl &NA);
+
   /// getOrCreateRecordType - Emit record type's standalone debug info.
   llvm::DIType getOrCreateRecordType(QualType Ty, SourceLocation L);
 

clang/lib/CodeGen/CGDecl.cpp

@@ -79,7 +79,6 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
   case Decl::Enum:      // enum X;
   case Decl::EnumConstant: // enum ? { X = ? }
   case Decl::CXXRecord: // struct/union/class X; [C++]
-  case Decl::NamespaceAlias:
   case Decl::StaticAssert: // static_assert(X, ""); [C++0x]
   case Decl::Label:        // __label__ x;
   case Decl::Import:
@@ -88,6 +87,10 @@ void CodeGenFunction::EmitDecl(const Decl &D) {
     // None of these decls require codegen support.
     return;
 
+  case Decl::NamespaceAlias:
+    if (CGDebugInfo *DI = getDebugInfo())
+        DI->EmitNamespaceAlias(cast<NamespaceAliasDecl>(D));
+    return;
   case Decl::Using:          // using X; [C++]
     if (CGDebugInfo *DI = getDebugInfo())
         DI->EmitUsingDecl(cast<UsingDecl>(D));

clang/lib/CodeGen/CodeGenModule.cpp

@@ -2879,10 +2879,13 @@ void CodeGenModule::EmitTopLevelDecl(Decl *D) {
   case Decl::ClassTemplate:
   case Decl::FunctionTemplate:
   case Decl::TypeAliasTemplate:
-  case Decl::NamespaceAlias:
   case Decl::Block:
   case Decl::Empty:
     break;
+  case Decl::NamespaceAlias:
+    if (CGDebugInfo *DI = getModuleDebugInfo())
+        DI->EmitNamespaceAlias(cast<NamespaceAliasDecl>(*D));
+    return;
   case Decl::UsingDirective: // using namespace X; [C++]
     if (CGDebugInfo *DI = getModuleDebugInfo())
       DI->EmitUsingDirective(cast<UsingDirectiveDecl>(*D));

clang/test/CodeGenCXX/debug-info-namespace.cpp

@@ -16,6 +16,7 @@ using namespace B;
 }
 
 using namespace A;
+namespace E = A;
 
 int func(bool b) {
   if (b) {
@@ -28,7 +29,9 @@ int func(bool b) {
   using B::f1;
   using B::i;
   using B::baz;
-  return i;
+  namespace X = A;
+  namespace Y = X;
+  return i + X::B::i + Y::B::i;
 }
 
 // This should work even if 'i' and 'func' were declarations & not definitions,
@@ -40,23 +43,26 @@ int func(bool b) {
 // CHECK: [[NS:![0-9]*]] = {{.*}}, metadata [[FILE2:![0-9]*]], metadata [[CTXT:![0-9]*]], {{.*}} ; [ DW_TAG_namespace ] [B] [line 1]
 // CHECK: [[CTXT]] = {{.*}}, metadata [[FILE]], null, {{.*}} ; [ DW_TAG_namespace ] [A] [line 5]
 // CHECK: [[F1:![0-9]*]] {{.*}} ; [ DW_TAG_subprogram ] [line 4] [def] [f1]
-// CHECK: [[FUNC:![0-9]*]] {{.*}} ; [ DW_TAG_subprogram ] [line 14] [def] [func]
+// CHECK: [[FUNC:![0-9]*]] {{.*}} ; [ DW_TAG_subprogram ] [line 15] [def] [func]
 // CHECK: [[FILE2]]} ; [ DW_TAG_file_type ] [{{.*}}foo.cpp]
 // CHECK: [[I:![0-9]*]] = {{.*}}, metadata [[NS]], metadata !"i", {{.*}} ; [ DW_TAG_variable ] [i]
-// CHECK: [[MODULES]] = metadata !{metadata [[M1:![0-9]*]], metadata [[M2:![0-9]*]], metadata [[M3:![0-9]*]], metadata [[M4:![0-9]*]], metadata [[M5:![0-9]*]], metadata [[M6:![0-9]*]], metadata [[M7:![0-9]*]], metadata [[M8:![0-9]*]], metadata [[M9:![0-9]*]]}
+// CHECK: [[MODULES]] = metadata !{metadata [[M1:![0-9]*]], metadata [[M2:![0-9]*]], metadata [[M3:![0-9]*]], metadata [[M4:![0-9]*]], metadata [[M5:![0-9]*]], metadata [[M6:![0-9]*]], metadata [[M7:![0-9]*]], metadata [[M8:![0-9]*]], metadata [[M9:![0-9]*]], metadata [[M10:![0-9]*]], metadata [[M11:![0-9]*]], metadata [[M12:![0-9]*]]}
 // CHECK: [[M1]] = metadata !{i32 {{[0-9]*}}, metadata [[CTXT]], metadata [[NS]], i32 9} ; [ DW_TAG_imported_module ]
 // CHECK: [[M2]] = metadata !{i32 {{[0-9]*}}, metadata [[CU]], metadata [[CTXT]], i32 12} ; [ DW_TAG_imported_module ]
-// CHECK: [[M3]] = metadata !{i32 {{[0-9]*}}, metadata [[LEX:![0-9]*]], metadata [[NS]], i32 16} ; [ DW_TAG_imported_module ]
-// CHECK: [[LEX]] = metadata !{i32 {{[0-9]*}}, metadata [[FILE2]], metadata [[FUNC]], i32 15, i32 0, i32 0} ; [ DW_TAG_lexical_block ]
-// CHECK: [[M4]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[CTXT]], i32 19} ; [ DW_TAG_imported_module ]
-// CHECK: [[M5]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[FOO:![0-9]*]], i32 20} ; [ DW_TAG_imported_declaration ]
+// CHECK: [[M3]] = metadata !{i32 {{[0-9]*}}, metadata [[CU]], metadata [[CTXT]], i32 13, metadata !"E"} ; [ DW_TAG_imported_module ]
+// CHECK: [[M4]] = metadata !{i32 {{[0-9]*}}, metadata [[LEX:![0-9]*]], metadata [[NS]], i32 17} ; [ DW_TAG_imported_module ]
+// CHECK: [[LEX]] = metadata !{i32 {{[0-9]*}}, metadata [[FILE2]], metadata [[FUNC]], i32 16, i32 0, i32 0} ; [ DW_TAG_lexical_block ]
+// CHECK: [[M5]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[CTXT]], i32 20} ; [ DW_TAG_imported_module ]
+// CHECK: [[M6]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[FOO:![0-9]*]], i32 21} ; [ DW_TAG_imported_declaration ]
 // CHECK: [[FOO]] {{.*}} ; [ DW_TAG_structure_type ] [foo] [line 5, size 0, align 0, offset 0] [fwd] [from ]
-// CHECK: [[M6]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[BAR:![0-9]*]], i32 21} ; [ DW_TAG_imported_declaration ]
+// CHECK: [[M7]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[BAR:![0-9]*]], i32 22} ; [ DW_TAG_imported_declaration ]
 // CHECK: [[BAR]] {{.*}} ; [ DW_TAG_structure_type ] [bar] [line 6, {{.*}}] [fwd] [from ]
-// CHECK: [[M7]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[F1]], i32 22} ; [ DW_TAG_imported_declaration ]
-// CHECK: [[M8]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[I]], i32 23} ; [ DW_TAG_imported_declaration ]
-// CHECK: [[M9]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[BAZ:![0-9]*]], i32 24} ; [ DW_TAG_imported_declaration ]
+// CHECK: [[M8]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[F1]], i32 23} ; [ DW_TAG_imported_declaration ]
+// CHECK: [[M9]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[I]], i32 24} ; [ DW_TAG_imported_declaration ]
+// CHECK: [[M10]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[BAZ:![0-9]*]], i32 25} ; [ DW_TAG_imported_declaration ]
 // CHECK: [[BAZ]] = metadata !{i32 {{[0-9]*}}, metadata [[FOOCPP]], metadata [[NS]], {{.*}} ; [ DW_TAG_typedef ] [baz] {{.*}} [from bar]
+// CHECK: [[M11]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[CTXT]], i32 26, metadata !"X"} ; [ DW_TAG_imported_module ]
+// CHECK: [[M12]] = metadata !{i32 {{[0-9]*}}, metadata [[FUNC]], metadata [[M11]], i32 27, metadata !"Y"} ; [ DW_TAG_imported_module ]
 
 // CHECK-GMLT: [[CU:![0-9]*]] = {{.*}}[[MODULES:![0-9]*]], metadata !""} ; [ DW_TAG_compile_unit ]
 // CHECK-GMLT: [[MODULES]] = metadata !{i32 0}