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[ObjC][DWARF] Emit DW_AT_APPLE_objc_direct for methods marked as __at…
…tribute__((objc_direct)) Summary: With DWARF5 it is no longer possible to distinguish normal methods and methods with `__attribute__((objc_direct))` by just looking at the debug information as they are both now children of the of the DW_TAG_structure_type that defines them (before only the `__attribute__((objc_direct))` methods were children). This means that in LLDB we are no longer able to create a correct Clang AST of a module by just looking at the debug information. Instead we would need to call the Objective-C runtime to see which of the methods have a `__attribute__((objc_direct))` and then add the attribute to our own Clang AST depending on what the runtime returns. This would mean that we either let the module AST be dependent on the Objective-C runtime (which doesn't seem right) or we retroactively add the missing attribute to the imported AST in our expressions. A third option is to annotate methods with `__attribute__((objc_direct))` as `DW_AT_APPLE_objc_direct` which is what this patch implements. This way LLDB doesn't have to call the runtime for any `__attribute__((objc_direct))` method and the AST in our module will already be correct when we create it. Reviewers: aprantl, SouraVX Reviewed By: aprantl Subscribers: hiraditya, cfe-commits, llvm-commits Tags: #clang, #llvm, #debug-info Differential Revision: https://reviews.llvm.org/D71201
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,54 @@ | ||
; RUN: llc < %s -filetype=obj -o %t | ||
; RUN: llvm-dwarfdump -v %t | FileCheck %s | ||
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; Source code to regenerate: | ||
; __attribute__((objc_root_class)) | ||
; @interface Root | ||
; - (int)direct_method __attribute__((objc_direct)); | ||
; @end | ||
; | ||
; @implementation Root | ||
; - (int)direct_method __attribute__((objc_direct)) { | ||
; return 42; | ||
; } | ||
; @end | ||
; | ||
; clang -O0 -g -gdwarf-5 direct.m -c | ||
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; CHECK: DW_TAG_subprogram [3] | ||
; CHECK: DW_AT_APPLE_objc_direct | ||
; CHECK-SAME: DW_FORM_flag_present | ||
; CHECK: DW_TAG_formal_parameter [4] | ||
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; ModuleID = 'direct.bc' | ||
source_filename = "direct.m" | ||
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%0 = type opaque | ||
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define hidden i32 @"\01-[Root direct_method]"(%0* %self, i8* %_cmd) { | ||
entry: | ||
%retval = alloca i32, align 4 | ||
%0 = load i32, i32* %retval, align 4 | ||
ret i32 %0 | ||
} | ||
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!llvm.dbg.cu = !{!0} | ||
!llvm.module.flags = !{!19, !20} | ||
!llvm.ident = !{} | ||
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!0 = distinct !DICompileUnit(language: DW_LANG_ObjC, file: !1, producer: "clang version 10.0.0 (https://github.com/llvm/llvm-project d6b2f33e2b6338d24cf756ba220939aecc81210d)", isOptimized: false, runtimeVersion: 2, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None) | ||
!1 = !DIFile(filename: "direct.m", directory: "/", checksumkind: CSK_MD5, checksum: "6b49fad130344b0011fc0eef65949390") | ||
!2 = !{} | ||
!3 = !{!4} | ||
!4 = !DICompositeType(tag: DW_TAG_structure_type, name: "Root", scope: !1, file: !1, line: 2, flags: DIFlagObjcClassComplete, elements: !5, runtimeLang: DW_LANG_ObjC) | ||
!5 = !{!6} | ||
!6 = !DISubprogram(name: "-[Root direct_method]", scope: !4, file: !1, line: 7, type: !7, scopeLine: 7, flags: DIFlagPrototyped, spFlags: DISPFlagObjCDirect, retainedNodes: !2) | ||
!7 = !DISubroutineType(types: !8) | ||
!8 = !{!9, !10, !11} | ||
!9 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) | ||
!10 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !4, size: 64, flags: DIFlagArtificial | DIFlagObjectPointer) | ||
!11 = !DIDerivedType(tag: DW_TAG_typedef, name: "SEL", file: !1, baseType: !12, flags: DIFlagArtificial) | ||
!12 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !13, size: 64) | ||
!13 = !DICompositeType(tag: DW_TAG_structure_type, name: "objc_selector", file: !1, flags: DIFlagFwdDecl) | ||
!19 = !{i32 7, !"Dwarf Version", i32 5} | ||
!20 = !{i32 2, !"Debug Info Version", i32 3} |