From e6c0e339133092d912209e4166ec2a6e88fecebe Mon Sep 17 00:00:00 2001 From: Adrian Prantl Date: Tue, 8 Nov 2016 22:11:38 +0000 Subject: [PATCH] Emit the DW_AT_type for a C++ static member definition if it is more specific than the one in its DW_AT_specification. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If a static member is an array, the translation unit containing the member definition may have a more specific type (including its length) than TUs only seeing the class declaration. This patch adds a DW_AT_type to the member's DW_TAG_variable in addition to the DW_AT_specification in these cases. The member type in the DW_AT_specification still shows the more generic type (without the length) to avoid defeating type uniquing. The DWARF standard discourages “duplicating” a DW_AT_type in a member variable definition but doesn’t explicitly forbid it. Having the more specific type (with the array length) available is what allows the debugger to print the contents of a static array member variable. https://reviews.llvm.org/D26368 rdar://problem/28706946 llvm-svn: 286302 --- lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp | 4 ++ test/DebugInfo/X86/static_member_array.ll | 71 +++++++++++++++++++++ 2 files changed, 75 insertions(+) create mode 100644 test/DebugInfo/X86/static_member_array.ll diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp index 8b5df7c7aef..1aabf69cb1a 100644 --- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp @@ -99,6 +99,10 @@ DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE( // We need the declaration DIE that is in the static member's class. DIE *VariableSpecDIE = getOrCreateStaticMemberDIE(SDMDecl); addDIEEntry(*VariableDIE, dwarf::DW_AT_specification, *VariableSpecDIE); + // If the global variable's type is different from the one in the class + // member type, assume that it's more specific and also emit it. + if (GTy != DD->resolve(SDMDecl->getBaseType())) + addType(*VariableDIE, GTy); } else { DeclContext = GV->getScope(); // Add name and type. diff --git a/test/DebugInfo/X86/static_member_array.ll b/test/DebugInfo/X86/static_member_array.ll new file mode 100644 index 00000000000..7377ab3d6f7 --- /dev/null +++ b/test/DebugInfo/X86/static_member_array.ll @@ -0,0 +1,71 @@ +; RUN: %llc_dwarf %s -filetype=obj -o - | llvm-dwarfdump -debug-dump=info - | FileCheck %s +; Generated from: +; +; struct A { +; static int fully_specified; +; static int smem[]; +; }; +; +; int A::fully_specified; +; int A::smem[] = { 0, 1, 2, 3 }; +; +; CHECK: DW_TAG_variable +; CHECK-NEXT: DW_AT_specification{{.*}}"fully_specified" +; CHECK-NOT: DW_AT_type +; CHECK: DW_TAG_structure_type +; CHECK: DW_TAG_member +; CHECK: DW_TAG_member +; CHECK-NEXT: DW_AT_name {{.*}} "smem" +; CHECK-NEXT: DW_AT_type {{.*}} {0x[[GENERIC:[0-9]+]]} +; +; CHECK: 0x[[GENERIC]]: DW_TAG_array_type +; CHECK-NOT: DW_TAG +; CHECK-NOT: NULL +; CHECK: DW_TAG_subrange_type +; CHECK-NOT: DW_AT_count +; CHECK: NULL +; +; CHECK: DW_TAG_variable +; CHECK-NEXT: DW_AT_specification {{.*}}"smem" +; CHECK-NEXT: DW_AT_type {{.*}} {0x[[SPECIFIC:[0-9]+]]} +; +; CHECK: 0x[[SPECIFIC]]: DW_TAG_array_type +; CHECK-NOT: DW_TAG +; CHECK-NOT: NULL +; CHECK: DW_TAG_subrange_type +; CHECK-NOT: DW_TAG +; CHECK-NOT: NULL +; CHECK: DW_AT_count {{.*}} (0x04) + +source_filename = "static_member_array.cpp" +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-apple-macosx10.12.0" + +@_ZN1A15fully_specifiedE = global i32 0, align 4, !dbg !0 +@_ZN1A4smemE = global [4 x i32] [i32 0, i32 1, i32 2, i32 3], align 16, !dbg !5 + +!llvm.dbg.cu = !{!1} +!llvm.module.flags = !{!17, !18, !19} +!llvm.ident = !{!20} + +!0 = distinct !DIGlobalVariable(name: "fully_specified", linkageName: "_ZN1A15fully_specifiedE", scope: !1, file: !2, line: 7, type: !7, isLocal: false, isDefinition: true, declaration: !13) +!1 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "clang version 4.0.0 (trunk 286129) (llvm/trunk 286128)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !3, globals: !4) +!2 = !DIFile(filename: "static_member_array.cpp", directory: "/Volumes/Data/radar/28706946") +!3 = !{} +!4 = !{!0, !5} +!5 = distinct !DIGlobalVariable(name: "smem", linkageName: "_ZN1A4smemE", scope: !1, file: !2, line: 8, type: !6, isLocal: false, isDefinition: true, declaration: !10) +!6 = !DICompositeType(tag: DW_TAG_array_type, baseType: !7, size: 128, elements: !8) +!7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!8 = !{!9} +!9 = !DISubrange(count: 4) +!10 = !DIDerivedType(tag: DW_TAG_member, name: "smem", scope: !11, file: !2, line: 4, baseType: !14, flags: DIFlagStaticMember) +!11 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "A", file: !2, line: 1, size: 8, elements: !12, identifier: "_ZTS1A") +!12 = !{!13, !10} +!13 = !DIDerivedType(tag: DW_TAG_member, name: "fully_specified", scope: !11, file: !2, line: 3, baseType: !7, flags: DIFlagStaticMember) +!14 = !DICompositeType(tag: DW_TAG_array_type, baseType: !7, elements: !15) +!15 = !{!16} +!16 = !DISubrange(count: -1) +!17 = !{i32 2, !"Dwarf Version", i32 4} +!18 = !{i32 2, !"Debug Info Version", i32 3} +!19 = !{i32 1, !"PIC Level", i32 2} +!20 = !{!"clang version 4.0.0 (trunk 286129) (llvm/trunk 286128)"}