[DebugMetadata][DwarfDebug] Don't retain local types with -fno-eliminate-unused-debug-types

[dzhidzhoev]

Summary

Don't retain local types in DICompileUnit, only attach them to the
corresponding subprogram, as it is more clear.

It's supposed to be committed along with https://reviews.llvm.org/D144006.

[nickdesaulniers]

Seems fine to me, but please triple check as the presubmit tests are failing.

Perhaps you meant to mark this as a parent or child revision in phab with your other change, so that the presubmit builds know to apply both?

See the box in the top right; Edit Related Revisions.

[dzhidzhoev]

In D158730#4614172, @nickdesaulniers wrote:

Seems fine to me, but please triple check as the presubmit tests are failing.

Perhaps you meant to mark this as a parent or child revision in phab with your other change, so that the presubmit builds know to apply both?

See the box in the top right; Edit Related Revisions.

Thanks! Added related revisions.

[dzhidzhoev]

Rebased on top of https://reviews.llvm.org/D155818.

[dblaikie]

Nice and easy

clang/test/CodeGen/debug-info-unused-types.c

 }
 
 // Check that debug info is emitted for the typedef, struct, enum, and union
 // when -fno-eliminate-unused-debug-types and -g are set.
 
 // CHECK: !DICompileUnit{{.+}}retainedTypes: [[RETTYPES:![0-9]+]]
 // CHECK: [[TYPE0:![0-9]+]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "bar"
 // CHECK: [[TYPE1:![0-9]+]] = !DIEnumerator(name: "BAR"
-// CHECK: [[TYPE2:![0-9]+]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "z"
-// CHECK: [[TYPE3:![0-9]+]] = !DIEnumerator(name: "Z"
-// CHECK: [[RETTYPES]] = !{[[TYPE4:![0-9]+]], [[TYPE5:![0-9]+]], [[TYPE0]], [[TYPE6:![0-9]+]], {{![0-9]+}}, [[TYPE7:![0-9]+]], [[TYPE2]], [[TYPE8:![0-9]+]]}
-// CHECK: [[TYPE4]] = !DIDerivedType(tag: DW_TAG_typedef, name: "my_int"
-// CHECK: [[TYPE5]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "foo"
-// CHECK: [[TYPE6]] = distinct !DICompositeType(tag: DW_TAG_union_type, name: "baz"
-// CHECK: [[TYPE7]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "y"
+// CHECK: [[RETTYPES]] = !{[[TYPE2:![0-9]+]], [[TYPE3:![0-9]+]], [[TYPE0]], [[TYPE4:![0-9]+]], {{![0-9]+}}}
+// CHECK: [[TYPE2]] = !DIDerivedType(tag: DW_TAG_typedef, name: "my_int"
+// CHECK: [[TYPE3]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "foo"
+// CHECK: [[TYPE4]] = distinct !DICompositeType(tag: DW_TAG_union_type, name: "baz"
+// CHECK: [[SP:![0-9]+]] = distinct !DISubprogram(name: "quux", {{.*}}, retainedNodes: [[SPRETNODES:![0-9]+]]
+// CHECK: [[SPRETNODES]] = !{[[TYPE5:![0-9]+]], [[TYPE6:![0-9]+]], [[TYPE8:![0-9]+]]}
+// CHECK: [[TYPE5]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "y"
+// CHECK: [[TYPE6]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "z"
+// CHECK: [[TYPE7:![0-9]+]] = !DIEnumerator(name: "Z"
 // CHECK: [[TYPE8]] = distinct !DICompositeType(tag: DW_TAG_union_type, name: "w"
 
 // Check that debug info is not emitted for the typedef, struct, enum, and
 // union when -fno-eliminate-unused-debug-types and -g are not set. These are
 // the same checks as above with `NODBG-NOT` rather than `CHECK`.
 
 // NODBG-NOT: !DI{{CompositeType|Enumerator|DerivedType}}
 

clang/test/CodeGen/debug-info-unused-types.cpp

 // RUN: %clang_cc1 -debug-info-kind=unused-types -emit-llvm -o - %s | FileCheck %s
 // RUN: %clang_cc1 -debug-info-kind=limited -emit-llvm -o - %s | FileCheck --check-prefix=NODBG %s
 using foo = int;
 class bar {};
 enum class baz { BAZ };
 
 void quux() {
   using x = int;
   class y {};
   enum class z { Z };
 }
 
 // CHECK: !DICompileUnit{{.+}}retainedTypes: [[RETTYPES:![0-9]+]]
 // CHECK: [[TYPE0:![0-9]+]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "baz"
 // CHECK: [[TYPE1:![0-9]+]] = !DIEnumerator(name: "BAZ"
-// CHECK: [[TYPE2:![0-9]+]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "z"
-// CHECK: [[TYPE3:![0-9]+]] = !DIEnumerator(name: "Z"
-// CHECK: [[RETTYPES]] = !{[[TYPE4:![0-9]+]], [[TYPE5:![0-9]+]], [[TYPE0]], {{![0-9]+}}, [[TYPE6:![0-9]+]], [[TYPE2]]}
-// CHECK: [[TYPE4]] = !DIDerivedType(tag: DW_TAG_typedef, name: "foo"
-// CHECK: [[TYPE5]] = distinct !DICompositeType(tag: DW_TAG_class_type, name: "bar"
-// CHECK: [[TYPE6]] = distinct !DICompositeType(tag: DW_TAG_class_type, name: "y"
+// CHECK: [[RETTYPES]] = !{[[TYPE2:![0-9]+]], [[TYPE3:![0-9]+]], [[TYPE0]], {{![0-9]+}}}
+// CHECK: [[TYPE2]] = !DIDerivedType(tag: DW_TAG_typedef, name: "foo"
+// CHECK: [[TYPE3]] = distinct !DICompositeType(tag: DW_TAG_class_type, name: "bar"
+// CHECK: [[SP:![0-9]+]] = distinct !DISubprogram(name: "quux", {{.*}}, retainedNodes: [[SPRETNODES:![0-9]+]]
+// CHECK: [[SPRETNODES]] = !{[[TYPE4:![0-9]+]], [[TYPE5:![0-9]+]]}
+// CHECK: [[TYPE4]] = distinct !DICompositeType(tag: DW_TAG_class_type, name: "y", scope: [[SP]]
+// CHECK: [[TYPE5]] = !DICompositeType(tag: DW_TAG_enumeration_type, name: "z", scope: [[SP]]
+// CHECK: [[TYPE6:![0-9]+]] = !DIEnumerator(name: "Z"
 
 // NODBG-NOT: !DI{{CompositeType|Enumerator|DerivedType}}
 
 class unused_class;
 enum class unused_enum_class;
 
 // NODBG-NOT: name: "unused_

llvm/lib/IR/DIBuilder.cpp

DIType *DIBuilder::createObjectPointerType(DIType *Ty) {
   return createTypeWithFlags(Ty, Flags);
 }
 
 void DIBuilder::retainType(DIScope *T) {
   assert(T && "Expected non-null type");
   assert((isa<DIType>(T) || (isa<DISubprogram>(T) &&
                              cast<DISubprogram>(T)->isDefinition() == false)) &&
          "Expected type or subprogram declaration");
+  if (!isa_and_nonnull<DILocalScope>(T->getScope()))
     AllRetainTypes.emplace_back(T);
 }
 
 DIBasicType *DIBuilder::createUnspecifiedParameter() { return nullptr; }
 
 DICompositeType *
 DIBuilder::createForwardDecl(unsigned Tag, StringRef Name, DIScope *Scope,
                              DIFile *F, unsigned Line, unsigned RuntimeLang,
                              uint64_t SizeInBits, uint32_t AlignInBits,