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Debug Info: Support for DW_AT_export_symbols for anonymous structs 

This implements the DWARF 5 feature described in:

http://dwarfstd.org/ShowIssue.php?issue=141212.1

To support recognizing anonymous structs:

  struct A {
    struct { // Anonymous struct
        int y;
    };
  } a

This patch adds support for the new flag in constructTypeDIE(...) and test to verify this change.

Differential Revision: https://reviews.llvm.org/D66605

llvm-svn: 369969
This commit is contained in:
Shafik Yaghmour 2019-08-26 20:59:44 +00:00
parent 72797ba072
commit 90e00bd8f3
2 changed files with 46 additions and 0 deletions
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3
llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
View File

@ -946,6 +946,9 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, const DICompositeType *CTy) {
if (CTy->isAppleBlockExtension())
addFlag(Buffer, dwarf::DW_AT_APPLE_block);
if (CTy->getExportSymbols())
addFlag(Buffer, dwarf::DW_AT_export_symbols);
// This is outside the DWARF spec, but GDB expects a DW_AT_containing_type
// inside C++ composite types to point to the base class with the vtable.
// Rust uses DW_AT_containing_type to link a vtable to the type

43
llvm/test/DebugInfo/Generic/export-symbol-anonymous-class.ll Normal file
View File

@ -0,0 +1,43 @@
; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -debug-info - | FileCheck %s
;
; struct A {
; // Anonymous class exports its symbols into A
; struct {
; int y;
; };
; } a;
;
; CHECK: DW_TAG_structure_type
; CHECK-NEXT: DW_AT_calling_convention (DW_CC_pass_by_value)
; CHECK-NEXT: DW_AT_name ("A")
;
; CHECK-NOT: NULL
;
; CHECK: DW_TAG_structure_type
; CHECK-NEXT: DW_AT_export_symbols (true)
%struct.A = type { %struct.anon }
%struct.anon = type { i32 }
@a = global %struct.A zeroinitializer, align 4, !dbg !0
!llvm.module.flags = !{!14, !15}
!llvm.dbg.cu = !{!2}
!llvm.ident = !{!16}
!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
!1 = distinct !DIGlobalVariable(name: "a", scope: !2, file: !3, line: 5, type: !6, isLocal: false, isDefinition: true)
!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 10.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: GNU)
!3 = !DIFile(filename: "simple_anon_class.cpp", directory: "/dir")
!4 = !{}
!5 = !{!0}
!6 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "A", file: !3, line: 1, size: 32, flags: DIFlagTypePassByValue, elements: !7, identifier: "_ZTS1A")
!7 = !{!8}
!8 = !DIDerivedType(tag: DW_TAG_member, scope: !6, file: !3, line: 2, baseType: !9, size: 32)
!9 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !6, file: !3, line: 2, size: 32, flags: DIFlagExportSymbols | DIFlagTypePassByValue, elements: !10, identifier: "_ZTSN1AUt_E")
!10 = !{!11}
!11 = !DIDerivedType(tag: DW_TAG_member, name: "y", scope: !9, file: !3, line: 3, baseType: !12, size: 32)
!12 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!14 = !{i32 2, !"Dwarf Version", i32 4}
!15 = !{i32 2, !"Debug Info Version", i32 3}
!16 = !{!"clang version 10.0.0"}