[DebugInfo] Add DW_AT_artificial for compiler generated static member. #115851
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode characters
Consider the case when the compiler generates a static member. Any consumer of the debug info generated for that case, would benefit if that member has the DW_AT_artificial flag.
CarlosAlbertoEnciso requested review from OCHyams, SLTozer, adrian-prantl, dwblaikie, jmorse, jryans and pogo59 
Member
| @llvm/pr-subscribers-debuginfo Author: Carlos Alberto Enciso (CarlosAlbertoEnciso) ChangesConsider the case when the compiler generates a static member. Any consumer of the debug info generated for that case, would benefit if that member has the DW_AT_artificial flag. Full diff: https://github.com/llvm/llvm-project/pull/115851.diff 2 Files Affected:
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp index c6d9fcfb0b76c1..76f7b0920434bb 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp +++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp @@ -1784,6 +1784,10 @@ DIE *DwarfUnit::getOrCreateStaticMemberDIE(const DIDerivedType *DT) { addFlag(StaticMemberDIE, dwarf::DW_AT_external); addFlag(StaticMemberDIE, dwarf::DW_AT_declaration); + // Consider the case when the static member was created by the compiler. + if (DT->isArtificial()) + addFlag(StaticMemberDIE, dwarf::DW_AT_artificial); + // FIXME: We could omit private if the parent is a class_type, and // public if the parent is something else. addAccess(StaticMemberDIE, DT->getFlags()); diff --git a/llvm/test/DebugInfo/Generic/artificial-static-member.ll b/llvm/test/DebugInfo/Generic/artificial-static-member.ll new file mode 100644 index 00000000000000..3263c976e39158 --- /dev/null +++ b/llvm/test/DebugInfo/Generic/artificial-static-member.ll @@ -0,0 +1,41 @@ +; RUN: llc -O0 -filetype=obj < %s | \ +; RUN: llvm-dwarfdump --debug-info - | FileCheck %s + +; LLVM IR generated from: + +; struct S { +; static int Member; <-- Manually marked as artificial +; }; +; int S::Member = 1; + +source_filename = "artificial-static-member.cpp" +target triple = "x86_64-pc-linux-gnu" + +@_ZN1S6MemberE = dso_local global i32 1, align 4, !dbg !0 + +!llvm.dbg.cu = !{!2} +!llvm.module.flags = !{!9, !10} + +!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression()) +!1 = distinct !DIGlobalVariable(name: "Member", linkageName: "_ZN1S6MemberE", scope: !2, type: !5, isLocal: false, isDefinition: true, declaration: !6) +!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, emissionKind: FullDebug, globals: !4) +!3 = !DIFile(filename: "artificial-static-member.cpp", directory: "") +!4 = !{!0} +!5 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!6 = !DIDerivedType(tag: DW_TAG_variable, name: "Member", scope: !7, baseType: !5, flags: DIFlagArtificial | DIFlagStaticMember) +!7 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "S", size: 8, flags: DIFlagTypePassByValue, elements: !8, identifier: "_ZTS1S") +!8 = !{!6} +!9 = !{i32 7, !"Dwarf Version", i32 5} +!10 = !{i32 2, !"Debug Info Version", i32 3} + +; CHECK: {{.*}}DW_TAG_structure_type +; CHECK-NEXT: DW_AT_calling_convention +; CHECK-NEXT: DW_AT_name ("S") +; CHECK-NEXT: DW_AT_byte_size + +; CHECK: {{.*}}DW_TAG_variable +; CHECK-NEXT: DW_AT_name ("Member") +; CHECK-NEXT: DW_AT_type +; CHECK-NEXT: DW_AT_external (true) +; CHECK-NEXT: DW_AT_declaration (true) +; CHECK-NEXT: DW_AT_artificial (true) |
Collaborator
| Any particular compiler generated static variables you have in mind? There aren't any C++ ones that come to mind - though of course LLVM isn't just for Clang/C++, but would be nice to have some documented use case, if there is one, for this. If there isn't one we can document/mention, it's probably still OK to do though, it's simple enough/cheap enough that it's not a big deal. |
Member Author
| For classes with virtual functions, Clang generates a class member |
Member Author
| We want to allow our (SCE) debugger to have a direct access to the whole vtable, thru a static data member We need for the generated static data member to be |
Member Author
| @dwblaikie Thanks for your feedback. |
Collaborator
| LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/9521 Here is the relevant piece of the build log for the reference |
Member Author
Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/9521 Created PR that fix the test case: #116327 |
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit. This suggestion is invalid because no changes were made to the code. Suggestions cannot be applied while the pull request is closed. Suggestions cannot be applied while viewing a subset of changes. Only one suggestion per line can be applied in a batch. Add this suggestion to a batch that can be applied as a single commit. Applying suggestions on deleted lines is not supported. You must change the existing code in this line in order to create a valid suggestion. Outdated suggestions cannot be applied. This suggestion has been applied or marked resolved. Suggestions cannot be applied from pending reviews. Suggestions cannot be applied on multi-line comments. Suggestions cannot be applied while the pull request is queued to merge. Suggestion cannot be applied right now. Please check back later.
Consider the case when the compiler generates a static member. Any consumer of the debug info generated for that case, would benefit if that member has the DW_AT_artificial flag.