Module Debugging: Defer the emission of anonymous tag decls

until we are visiting their declcontext.

This fixes a regression introduced in r256962:
When building debug info for a typdef'd anonymous tag type, we would be
visiting the inner anonymous type first thus creating a "typedef changes
linkage of anonymous type, but linkage was already computed" error.

rdar://problem/24199640

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@258152 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/ObjectFilePCHContainerOperations.cpp

@@ -190,6 +190,10 @@ public:
     if (D->isFromASTFile())
       return;
 
+    // Anonymous tag decls are deferred until we are building their declcontext.
+    if (D->getName().empty())
+      return;
+
     DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx, false);
     DTV.TraverseDecl(D);
     Builder->UpdateCompletedType(D);

test/Modules/ExtDebugInfo.cpp

@@ -35,6 +35,10 @@ enum {
 auto anon_enum = DebugCXX::e2;
 char _anchor = anon_enum + conflicting_uid;
 
+TypedefUnion tdu;
+TypedefEnum tde;
+TypedefStruct tds;
+
 // CHECK: ![[NS:.*]] = !DINamespace(name: "DebugCXX", scope: ![[MOD:[0-9]+]],
 // CHECK: ![[MOD]] = !DIModule(scope: null, name: {{.*}}DebugCXX
 
@@ -62,6 +66,13 @@ char _anchor = anon_enum + conflicting_uid;
 // CHECK-SAME:             flags: DIFlagFwdDecl,
 // CHECK-SAME:             identifier: "_ZTSN8DebugCXX8TemplateIfNS_6traitsIfEEEE")
 
+// CHECK: !DICompositeType(tag: DW_TAG_union_type,
+// CHECK-SAME:             flags: DIFlagFwdDecl, identifier: "_ZTS12TypedefUnion")
+// CHECK: !DICompositeType(tag: DW_TAG_enumeration_type,
+// CHECK-SAME:             flags: DIFlagFwdDecl, identifier: "_ZTS11TypedefEnum")
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type,
+// CHECK-SAME:             flags: DIFlagFwdDecl, identifier: "_ZTS13TypedefStruct")
+
 // CHECK: !DIDerivedType(tag: DW_TAG_member, name: "static_member",
 // CHECK-SAME:           scope: !"_ZTSN8DebugCXX6StructE"
 

test/Modules/Inputs/DebugCXX.h

@@ -58,3 +58,7 @@ class FwdVirtual {
 };
 
 struct PureForwardDecl;
+
+typedef union { int i; } TypedefUnion;
+typedef enum { e0 = 0 } TypedefEnum;
+typedef struct { int i; } TypedefStruct;

test/Modules/ModuleDebugInfo.cpp

@@ -28,6 +28,10 @@
 // CHECK-SAME:             identifier: "_ZTSN8DebugCXX4EnumE")
 // CHECK: !DINamespace(name: "DebugCXX"
 
+// CHECK: !DICompositeType(tag: DW_TAG_enumeration_type,
+// CHECK-SAME-NOT:         name:
+// CHECK-SAME:             identifier: "_ZTS11TypedefEnum")
+
 // CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "Struct"
 // CHECK-SAME:             identifier: "_ZTSN8DebugCXX6StructE")
 
@@ -47,6 +51,14 @@
 // CHECK-SAME:             identifier: "_ZTS10FwdVirtual")
 // CHECK: !DIDerivedType(tag: DW_TAG_member, name: "_vptr$FwdVirtual"
 
+// CHECK: !DICompositeType(tag: DW_TAG_union_type,
+// CHECK-SAME-NOT:         name:
+// CHECK-SAME:             identifier: "_ZTS12TypedefUnion")
+
+// CHECK: !DICompositeType(tag: DW_TAG_structure_type,
+// CHECK-SAME-NOT:         name:
+// CHECK-SAME:             identifier: "_ZTS13TypedefStruct")
+
 // CHECK: !DIDerivedType(tag: DW_TAG_typedef, name: "FloatInstatiation"
 // no mangled name here yet.