[CodeView] Only add the Scoped flag for an enum type when it has an immediate function scope to match MSVC

[rnk]

lgtm, thanks!

lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

1815–1821

Please add a comment to indicate that clang never puts enums inside DILexicalBlock scopes. Enum types, as generated by clang, are always in function, class, or file scopes.

lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

   if (ImmediateScope && isa<DICompositeType>(ImmediateScope))
     CO |= ClassOptions::Nested;
 
-  // Put the Scoped flag on function-local types.
-  for (const DIScope *Scope = ImmediateScope; Scope != nullptr;
-       Scope = Scope->getScope().resolve()) {
-    if (isa<DISubprogram>(Scope)) {
+  // Put the Scoped flag on function-local types. MSVC puts this flag for enum
+  // type only when it has an immediate function scope. Clang never puts enums 
+  // inside DILexicalBlock scopes. Enum types, as generated by clang, are 
+  // always in function, class, or file scopes.
+  if (Ty->getTag() == dwarf::DW_TAG_enumeration_type) {
+    if (ImmediateScope && isa<DISubprogram>(ImmediateScope))
       CO |= ClassOptions::Scoped;
-      break;
+  } else {
+    for (const DIScope *Scope = ImmediateScope; Scope != nullptr;
+         Scope = Scope->getScope().resolve()) {
+      if (isa<DISubprogram>(Scope)) {
+        CO |= ClassOptions::Scoped;
+        break;
+      }
     }
   }
 

test/DebugInfo/COFF/enum-co.ll

+; RUN: llc < %s -filetype=obj | llvm-readobj - -codeview | FileCheck %s
+
+; Command to generate enum-co.ll
+; $ clang++ enum-co.cpp -S -emit-llvm -g -gcodeview -o enum-co.ll
+;
+;
+; #define DEFINE_FUNCTION(T) \
+;   T Func_##T(T &arg) { return arg; };
+;
+; enum Enum { ON, OFF };  // Expect: CO = HasUniqueName
+; Enum Func_Enum(Enum &arg) { return arg; }
+;
+; enum class EnumClass { RED, BLUE, NOTCARE }; // Expect: CO = HasUniqueName
+; EnumClass Func_EnumClass(EnumClass &arg) { return arg; }
+;
+; void Func() {
+;   enum ScopedEnum { ON, OFF }; // Expected: CO = HasUniqueName | Scoped
+;   ScopedEnum SE;
+;
+;   struct Struct {
+;     union Union {
+;       enum NestedEnum { RED, BLUE }; // Expected: CO = HasUniqueName | Nested
+;     };
+;     Union U;
+;   };
+;   Struct S;
+; }
+
+; CHECK: Format: COFF-x86-64
+; CHECK: Arch: x86_64
+; CHECK: AddressSize: 64bit
+; CHECK: CodeViewTypes [
+; CHECK:   Section: .debug$T (6)
+; CHECK:   Magic: 0x4
+; CHECK:   Enum ({{.*}}) {
+; CHECK:     TypeLeafKind: LF_ENUM (0x1507)
+; CHECK:     NumEnumerators: 2
+; CHECK:     Properties [ (0x200)
+; CHECK:       HasUniqueName (0x200)
+; CHECK:     ]
+; CHECK:     UnderlyingType: int (0x74)
+; CHECK:     FieldListType: <field list> ({{.*}})
+; CHECK:     Name: Enum
+; CHECK:     LinkageName: .?AW4Enum@@
+; CHECK:   }
+; CHECK:   Enum ({{.*}}) {
+; CHECK:     TypeLeafKind: LF_ENUM (0x1507)
+; CHECK:     NumEnumerators: 3
+; CHECK:     Properties [ (0x200)
+; CHECK:       HasUniqueName (0x200)
+; CHECK:     ]
+; CHECK:     UnderlyingType: int (0x74)
+; CHECK:     FieldListType: <field list> ({{.*}})
+; CHECK:     Name: EnumClass
+; CHECK:     LinkageName: .?AW4EnumClass@@
+; CHECK:   }
+; CHECK:   Enum ({{.*}}) {
+; CHECK:     TypeLeafKind: LF_ENUM (0x1507)
+; CHECK:     NumEnumerators: 2
+; CHECK:     Properties [ (0x300)
+; CHECK:       HasUniqueName (0x200)
+; CHECK:       Scoped (0x100)
+; CHECK:     ]
+; CHECK:     UnderlyingType: int (0x74)
+; CHECK:     FieldListType: <field list> ({{.*}})
+; CHECK:     Func::ScopedEnum
+; CHECK:     LinkageName: .?AW4ScopedEnum@?1??Func@@YAXXZ@
+; CHECK:   }
+; CHECK:   Enum ({{.*}}) {
+; CHECK:     TypeLeafKind: LF_ENUM (0x1507)
+; CHECK:     NumEnumerators: 2
+; CHECK:     Properties [ (0x208)
+; CHECK        HasUniqueName (0x200)
+; CHECK        Nested (0x8)
+; CHECK:     ]
+; CHECK:     UnderlyingType: int (0x74)
+; CHECK:     FieldListType: <field list> ({{.*}})
+; CHECK:     Name: Func::Struct::Union::NestedEnum
+; CHECK:     LinkageName: .?AW4NestedEnum@Union@Struct@?1??Func@@YAXXZ@
+; CHECK:   }
+
+
+; ModuleID = 'enum-co.cpp'
+source_filename = "enum-co.cpp"
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc19.15.26729"
+
+%struct.Struct = type { %"union.Func()::Struct::Union" }
+%"union.Func()::Struct::Union" = type { i8 }
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local i32 @"?Func_Enum@@YA?AW4Enum@@AEAW41@@Z"(i32* dereferenceable(4) %arg) #0 !dbg !30 {
+entry:
+  %arg.addr = alloca i32*, align 8
+  store i32* %arg, i32** %arg.addr, align 8
+  call void @llvm.dbg.declare(metadata i32** %arg.addr, metadata !34, metadata !DIExpression()), !dbg !35
+  %0 = load i32*, i32** %arg.addr, align 8, !dbg !35
+  %1 = load i32, i32* %0, align 4, !dbg !35
+  ret i32 %1, !dbg !35
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local i32 @"?Func_EnumClass@@YA?AW4EnumClass@@AEAW41@@Z"(i32* dereferenceable(4) %arg) #0 !dbg !36 {
+entry:
+  %arg.addr = alloca i32*, align 8
+  store i32* %arg, i32** %arg.addr, align 8
+  call void @llvm.dbg.declare(metadata i32** %arg.addr, metadata !40, metadata !DIExpression()), !dbg !41
+  %0 = load i32*, i32** %arg.addr, align 8, !dbg !41
+  %1 = load i32, i32* %0, align 4, !dbg !41
+  ret i32 %1, !dbg !41
+}
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local void @"?Func@@YAXXZ"() #0 !dbg !14 {
+entry:
+  %SE = alloca i32, align 4
+  %S = alloca %struct.Struct, align 1
+  call void @llvm.dbg.declare(metadata i32* %SE, metadata !42, metadata !DIExpression()), !dbg !43
+  call void @llvm.dbg.declare(metadata %struct.Struct* %S, metadata !44, metadata !DIExpression()), !dbg !45
+  ret void, !dbg !46
+}
+
+attributes #0 = { noinline nounwind optnone uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind readnone speculatable }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!25, !26, !27, !28}
+!llvm.ident = !{!29}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 8.0.0 (https://github.com/llvm-mirror/clang.git 9884fc1d0881576784e9b50da9eb61a5eb427f1c) (https://github.com/llvm-mirror/llvm.git 33b1a96b81ba4e33cfc4a129ce43b5331e16936b)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "enum-co.cpp", directory: "D:\5Cupstream\5Cllvm\5Ctest\5CDebugInfo\5CCOFF", checksumkind: CSK_MD5, checksum: "2e53b90441669acca735bad28ed3a1ab")
+!2 = !{!3, !8, !13, !18}
+!3 = !DICompositeType(tag: DW_TAG_enumeration_type, name: "Enum", file: !1, line: 4, baseType: !4, size: 32, elements: !5, identifier: ".?AW4Enum@@")
+!4 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!5 = !{!6, !7}
+!6 = !DIEnumerator(name: "ON", value: 0)
+!7 = !DIEnumerator(name: "OFF", value: 1)
+!8 = !DICompositeType(tag: DW_TAG_enumeration_type, name: "EnumClass", file: !1, line: 7, baseType: !4, size: 32, flags: DIFlagFixedEnum, elements: !9, identifier: ".?AW4EnumClass@@")
+!9 = !{!10, !11, !12}
+!10 = !DIEnumerator(name: "RED", value: 0)
+!11 = !DIEnumerator(name: "BLUE", value: 1)
+!12 = !DIEnumerator(name: "NOTCARE", value: 2)
+!13 = !DICompositeType(tag: DW_TAG_enumeration_type, name: "ScopedEnum", scope: !14, file: !1, line: 11, baseType: !4, size: 32, elements: !5, identifier: ".?AW4ScopedEnum@?1??Func@@YAXXZ@")
+!14 = distinct !DISubprogram(name: "Func", linkageName: "?Func@@YAXXZ", scope: !1, file: !1, line: 10, type: !15, isLocal: false, isDefinition: true, scopeLine: 10, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !17)
+!15 = !DISubroutineType(types: !16)
+!16 = !{null}
+!17 = !{}
+!18 = !DICompositeType(tag: DW_TAG_enumeration_type, name: "NestedEnum", scope: !19, file: !1, line: 16, baseType: !4, size: 32, elements: !24, identifier: ".?AW4NestedEnum@Union@Struct@?1??Func@@YAXXZ@")
+!19 = distinct !DICompositeType(tag: DW_TAG_union_type, name: "Union", scope: !20, file: !1, line: 15, size: 8, flags: DIFlagTypePassByValue | DIFlagTrivial, elements: !23, identifier: ".?ATUnion@Struct@?1??Func@@YAXXZ@")
+!20 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "Struct", scope: !14, file: !1, line: 14, size: 8, flags: DIFlagTypePassByValue | DIFlagTrivial, elements: !21, identifier: ".?AUStruct@?1??Func@@YAXXZ@")
+!21 = !{!19, !22}
+!22 = !DIDerivedType(tag: DW_TAG_member, name: "U", scope: !20, file: !1, line: 18, baseType: !19, size: 8)
+!23 = !{!18}
+!24 = !{!10, !11}
+!25 = !{i32 2, !"CodeView", i32 1}
+!26 = !{i32 2, !"Debug Info Version", i32 3}
+!27 = !{i32 1, !"wchar_size", i32 2}
+!28 = !{i32 7, !"PIC Level", i32 2}
+!29 = !{!"clang version 8.0.0 (https://github.com/llvm-mirror/clang.git 9884fc1d0881576784e9b50da9eb61a5eb427f1c) (https://github.com/llvm-mirror/llvm.git 33b1a96b81ba4e33cfc4a129ce43b5331e16936b)"}
+!30 = distinct !DISubprogram(name: "Func_Enum", linkageName: "?Func_Enum@@YA?AW4Enum@@AEAW41@@Z", scope: !1, file: !1, line: 5, type: !31, isLocal: false, isDefinition: true, scopeLine: 5, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !17)
+!31 = !DISubroutineType(types: !32)
+!32 = !{!3, !33}
+!33 = !DIDerivedType(tag: DW_TAG_reference_type, baseType: !3, size: 64)
+!34 = !DILocalVariable(name: "arg", arg: 1, scope: !30, file: !1, line: 5, type: !33)
+!35 = !DILocation(line: 5, scope: !30)
+!36 = distinct !DISubprogram(name: "Func_EnumClass", linkageName: "?Func_EnumClass@@YA?AW4EnumClass@@AEAW41@@Z", scope: !1, file: !1, line: 8, type: !37, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !17)
+!37 = !DISubroutineType(types: !38)
+!38 = !{!8, !39}
+!39 = !DIDerivedType(tag: DW_TAG_reference_type, baseType: !8, size: 64)
+!40 = !DILocalVariable(name: "arg", arg: 1, scope: !36, file: !1, line: 8, type: !39)
+!41 = !DILocation(line: 8, scope: !36)
+!42 = !DILocalVariable(name: "SE", scope: !14, file: !1, line: 12, type: !13)
+!43 = !DILocation(line: 12, scope: !14)
+!44 = !DILocalVariable(name: "S", scope: !14, file: !1, line: 20, type: !20)
+!45 = !DILocation(line: 20, scope: !14)
+!46 = !DILocation(line: 21, scope: !14, isImplicitCode: true)