CodeView - add static data members to global variable debug info.

Summary:
Add static data members to IR debug info's list of global variables
so that they are emitted as S_CONSTANT records.

Related to https://bugs.llvm.org/show_bug.cgi?id=41615.

Reviewers: rnk

Subscribers: aprantl, cfe-commits, llvm-commits, thakis

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D62167

llvm-svn: 362038

Author: amykhuang

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -4361,9 +4361,13 @@ void CGDebugInfo::EmitGlobalVariable(const ValueDecl *VD, const APValue &Init) {
     return;
   }
 
-  // Do not emit separate definitions for function local const/statics.
+  llvm::DIScope *DContext = nullptr;
+
+  // Do not emit separate definitions for function local consts.
   if (isa<FunctionDecl>(VD->getDeclContext()))
     return;
+
+  // Emit definition for static members in CodeView.
   VD = cast<ValueDecl>(VD->getCanonicalDecl());
   auto *VarD = cast<VarDecl>(VD);
   if (VarD->isStaticDataMember()) {
@@ -4375,10 +4379,16 @@ void CGDebugInfo::EmitGlobalVariable(const ValueDecl *VD, const APValue &Init) {
     // through its scope.
     RetainedTypes.push_back(
         CGM.getContext().getRecordType(RD).getAsOpaquePtr());
-    return;
-  }
 
-  llvm::DIScope *DContext = getDeclContextDescriptor(VD);
+    if (!CGM.getCodeGenOpts().EmitCodeView)
+      return;
+
+    // Use the global scope for static members.
+    DContext = getContextDescriptor(
+        cast<Decl>(CGM.getContext().getTranslationUnitDecl()), TheCU);
+  } else {
+    DContext = getDeclContextDescriptor(VD);
+  }
 
   auto &GV = DeclCache[VD];
   if (GV)

clang/test/CodeGenCXX/debug-info-static-member.cpp

@@ -1,6 +1,7 @@
 // RUN: %clangxx -target x86_64-unknown-unknown -g %s -emit-llvm -S -o - | FileCheck %s
 // RUN: %clangxx -target x86_64-unknown-unknown -g -std=c++98 %s -emit-llvm -S -o - | FileCheck %s
 // RUN: %clangxx -target x86_64-unknown-unknown -g -std=c++11 %s -emit-llvm -S -o - | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-windows-msvc -gcodeview -debug-info-kind=limited %s -emit-llvm -o - | FileCheck --check-prefix MSVC %s
 // PR14471
 
 // CHECK: @_ZN1C1aE = dso_local global i32 4, align 4, !dbg [[A:![0-9]+]]
@@ -35,6 +36,7 @@ class C
 // CHECK: [[A]] = !DIGlobalVariableExpression(var: [[AV:.*]], expr: !DIExpression())
 // CHECK: [[AV]] = distinct !DIGlobalVariable(name: "a",
 // CHECK-SAME:                                declaration: ![[DECL_A:[0-9]+]])
+// MSVC: distinct !DIGlobalVariable(name: "a"
 //
 // CHECK: !DICompositeType(tag: DW_TAG_enumeration_type, name: "X"{{.*}}, identifier: "_ZTS1X")
 // CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "anon_static_decl_struct"
@@ -48,6 +50,7 @@ int C::a = 4;
 // CHECK: [[B]] = !DIGlobalVariableExpression(var: [[BV:.*]], expr: !DIExpression())
 // CHECK: [[BV]] = distinct !DIGlobalVariable(name: "b",
 // CHECK-SAME:                                declaration: ![[DECL_B:[0-9]+]])
+// MSVC: distinct !DIGlobalVariable(name: "b"
 // CHECK: ![[DECL_B]] = !DIDerivedType(tag: DW_TAG_member, name: "b"
 // CHECK-NOT:                                 size:
 // CHECK-NOT:                                 align:
@@ -95,6 +98,7 @@ int C::a = 4;
 int C::b = 2;
 // CHECK: [[C]] = !DIGlobalVariableExpression(var: [[CV:.*]], expr: !DIExpression())
 // CHECK: [[CV]] = distinct !DIGlobalVariable(name: "c", {{.*}} declaration: ![[DECL_C]])
+// MSVC: distinct !DIGlobalVariable(name: "c"
 int C::c = 1;
 
 int main()
@@ -114,11 +118,18 @@ struct anon_static_decl_struct {
 };
 }
 
-
 int ref() {
   return anon_static_decl_struct::anon_static_decl_var;
 }
 
+// In MSVC, static data members should be emitted as global variables when used.
+// MSVC: !DIGlobalVariableExpression(var: [[ANON_STATIC_DECL:![0-9]+]],
+// MSVC-SAME: !DIExpression(DW_OP_constu, 117, DW_OP_stack_value)
+// MSVC: [[ANON_STATIC_DECL]] = distinct !DIGlobalVariable(name: "anon_static_decl_var"
+// MSVC: !DIGlobalVariableExpression(var: [[STATIC_DECL_TEMPL:![0-9]+]]
+// MSVC-SAME: !DIExpression(DW_OP_constu, 7, DW_OP_stack_value)
+// MSVC: [[STATIC_DECL_TEMPL]] = distinct !DIGlobalVariable(name: "static_decl_templ_var"
+
 template<typename T>
 struct static_decl_templ {
   static const int static_decl_templ_var = 7;

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

@@ -3069,7 +3069,12 @@ void CodeViewDebug::emitDebugInfoForGlobal(const CVGlobalVariable &CVGV) {
     OS.EmitBinaryData(SRef);
 
     OS.AddComment("Name");
-    emitNullTerminatedSymbolName(OS, DIGV->getDisplayName());
+    // Get fully qualified name if global is a static data member.
+    std::string Name = DIGV->getDisplayName();
+    if (const auto *MemberDecl = dyn_cast_or_null<DIDerivedType>(
+            DIGV->getRawStaticDataMemberDeclaration()))
+      Name = getFullyQualifiedName(MemberDecl->getScope(), Name);
+    emitNullTerminatedSymbolName(OS, Name);
     endSymbolRecord(SConstantEnd);
   }
 }

llvm/test/DebugInfo/COFF/global-constants.ll

@@ -3,18 +3,25 @@
 
 ; C++ source to regenerate:
 ; const int Test1 = 1;
+; struct Foo { static const int Test2 = 2; };
 ; int main() {
-;   return Test1;
+;   return Test1 + Foo::Test2;
 ; }
 ; $ clang t.cpp -S -emit-llvm -g -gcodeview -o t.ll
 
-; ASM-LABEL:  .long 241              # Symbol subsection for globals
+; ASM-LABEL:  .long 241             # Symbol subsection for globals
 
-; ASM:        .short {{.*-.*}}       # Record length
-; ASM:        .short 4359            # Record kind: S_CONSTANT
-; ASM-NEXT:   .long 4099             # Type
-; ASM-NEXT:   .byte 0x01, 0x00       # Value
-; ASM-NEXT:   .asciz "Test1"         # Name
+; ASM:        .short {{.*-.*}}      # Record length
+; ASM:        .short 4359           # Record kind: S_CONSTANT
+; ASM-NEXT:   .long 4099            # Type
+; ASM-NEXT:   .byte 0x01, 0x00      # Value
+; ASM-NEXT:   .asciz "Test1"        # Name
+
+; ASM:        .short {{.*-.*}}      # Record length
+; ASM:        .short 4359           # Record kind: S_CONSTANT
+; ASM:        .long 4099            # Type
+; ASM:        .byte 0x02, 0x00      # Value
+; ASM:        .asciz "Foo::Test2"   # Name
 
 ; OBJ:        CodeViewDebugInfo [
 ; OBJ:          Section: .debug$S
@@ -27,38 +34,52 @@
 ; OBJ-NEXT:         Value: 1
 ; OBJ-NEXT:         Name: Test1
 ; OBJ-NEXT:       }
+; OBJ:            ConstantSym {
+; OBJ-NEXT:         Kind: S_CONSTANT (0x1107)
+; OBJ-NEXT:         Type: const int (0x1003)
+; OBJ-NEXT:         Value: 2
+; OBJ-NEXT:         Name: Foo::Test2
+; OBJ-NEXT:       }
 
 ; ModuleID = 't.cpp'
 source_filename = "t.cpp"
 target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-pc-windows-msvc"
 
 ; Function Attrs: noinline norecurse nounwind optnone
-define dso_local i32 @main() #0 !dbg !13 {
+define dso_local i32 @main() #0 !dbg !19 {
 entry:
   %retval = alloca i32, align 4
   store i32 0, i32* %retval, align 4
-  ret i32 1, !dbg !16
+  ret i32 3, !dbg !22
 }
 
+attributes #0 = { noinline norecurse nounwind optnone "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "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-features"="+cx8,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
 !llvm.dbg.cu = !{!0}
-!llvm.module.flags = !{!9, !10, !11}
-!llvm.ident = !{!12}
+!llvm.module.flags = !{!15, !16, !17}
+!llvm.ident = !{!18}
 
-!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 9.0.0 (https://github.com/llvm/llvm-project.git 4a1902b6739e3087a03c0ac7ab85b640764e9335)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3, nameTableKind: None)
-!1 = !DIFile(filename: "<stdin>", directory: "C:\5Csrc\5Ctest", checksumkind: CSK_MD5, checksum: "0d5ef00bdd80bdb409a3deac9938f20d")
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 9.0.0 (https://github.com/llvm/llvm-project.git 2b66a49044196d8b90d95d7d3b5246ccbe3abc05)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, globals: !10, nameTableKind: None)
+!1 = !DIFile(filename: "<stdin>", directory: "C:\5Csrc\5Ctest", checksumkind: CSK_MD5, checksum: "77cff5e1c7b260440ed03b23c18809c3")
 !2 = !{}
 !3 = !{!4}
-!4 = !DIGlobalVariableExpression(var: !5, expr: !DIExpression(DW_OP_constu, 1, DW_OP_stack_value))
-!5 = distinct !DIGlobalVariable(name: "Test1", scope: !0, file: !6, line: 1, type: !7, isLocal: true, isDefinition: true)
-!6 = !DIFile(filename: "t.cpp", directory: "C:\5Csrc\5Ctest", checksumkind: CSK_MD5, checksum: "0d5ef00bdd80bdb409a3deac9938f20d")
-!7 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !8)
-!8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
-!9 = !{i32 2, !"CodeView", i32 1}
-!10 = !{i32 2, !"Debug Info Version", i32 3}
-!11 = !{i32 1, !"wchar_size", i32 2}
-!12 = !{!"clang version 9.0.0 (https://github.com/llvm/llvm-project.git 4a1902b6739e3087a03c0ac7ab85b640764e9335)"}
-!13 = distinct !DISubprogram(name: "main", scope: !6, file: !6, line: 3, type: !14, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
-!14 = !DISubroutineType(types: !15)
-!15 = !{!8}
-!16 = !DILocation(line: 4, scope: !13)
+!4 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "Foo", file: !5, line: 3, size: 8, flags: DIFlagTypePassByValue, elements: !6, identifier: ".?AUFoo@@")
+!5 = !DIFile(filename: "t.cpp", directory: "C:\5Csrc\5Ctest", checksumkind: CSK_MD5, checksum: "77cff5e1c7b260440ed03b23c18809c3")
+!6 = !{!7}
+!7 = !DIDerivedType(tag: DW_TAG_member, name: "Test2", scope: !4, file: !5, line: 4, baseType: !8, flags: DIFlagStaticMember, extraData: i32 2)
+!8 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !9)
+!9 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!10 = !{!11, !13}
+!11 = !DIGlobalVariableExpression(var: !12, expr: !DIExpression(DW_OP_constu, 1, DW_OP_stack_value))
+!12 = distinct !DIGlobalVariable(name: "Test1", scope: null, file: !5, line: 1, type: !8, isLocal: true, isDefinition: true)
+!13 = !DIGlobalVariableExpression(var: !14, expr: !DIExpression(DW_OP_constu, 2, DW_OP_stack_value))
+!14 = distinct !DIGlobalVariable(name: "Test2", scope: !0, file: !5, line: 4, type: !8, isLocal: true, isDefinition: true, declaration: !7)
+!15 = !{i32 2, !"CodeView", i32 1}
+!16 = !{i32 2, !"Debug Info Version", i32 3}
+!17 = !{i32 1, !"wchar_size", i32 2}
+!18 = !{!"clang version 9.0.0 (https://github.com/llvm/llvm-project.git 2b66a49044196d8b90d95d7d3b5246ccbe3abc05)"}
+!19 = distinct !DISubprogram(name: "main", scope: !5, file: !5, line: 7, type: !20, scopeLine: 7, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!20 = !DISubroutineType(types: !21)
+!21 = !{!9}
+!22 = !DILocation(line: 8, scope: !19)