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Differential D153809

[DebugInfo][AsmPrinter] Don't emit accelerator entries with empty names
ClosedPublic

Authored by fdeazeve on Jun 26 2023, 1:13 PM.

Details

Reviewers
dblaikie
JDevlieghere
Group Reviewers
debug-info
Commits
rGfc4f1efb6a05: [DebugInfo][AsmPrinter] Don't emit accelerator entries with empty names
Summary

The DWARF 5 specification says that:

All other debugging information entries without a DW_AT_name attribute are
excluded.

Clang started generating these variables for string literals, see D123534.

Diff Detail

Event Timeline

fdeazeve created this revision.Jun 26 2023, 1:13 PM
Herald added a project: Restricted Project. · View Herald TranscriptJun 26 2023, 1:13 PM
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fdeazeve requested review of this revision.Jun 26 2023, 1:13 PM
Herald added a project: Restricted Project. · View Herald TranscriptJun 26 2023, 1:13 PM
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fdeazeve added reviewers: debug-info, dblaikie, JDevlieghere.Jun 26 2023, 1:14 PM
dblaikie accepted this revision.Jun 26 2023, 2:22 PM

LGTM

This revision is now accepted and ready to land.Jun 26 2023, 2:22 PM
Harbormaster completed remote builds in B241294: Diff 534727.Jun 26 2023, 2:50 PM
Closed by commit rGfc4f1efb6a05: [DebugInfo][AsmPrinter] Don't emit accelerator entries with empty names (authored by fdeazeve). · Explain WhyJun 27 2023, 5:41 AM
This revision was automatically updated to reflect the committed changes.
fdeazeve added a commit: rGfc4f1efb6a05: [DebugInfo][AsmPrinter] Don't emit accelerator entries with empty names.
scott.linder mentioned this in D153550: [DWARFVerifier] Fix verification of nameless variables..Jun 27 2023, 10:35 AM

Revision Contents

PathSize
llvm/
lib/
CodeGen/
AsmPrinter/
2 lines
test/
DebugInfo/
Generic/
22 lines

Diff 534727

llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp

Show First 20 Lines • Show All 3,530 Lines • ▼ Show 20 Lines
// Add the Name along with its companion DIE to the appropriate accelerator // Add the Name along with its companion DIE to the appropriate accelerator
// table (for AccelTableKind::Dwarf it's always AccelDebugNames, for // table (for AccelTableKind::Dwarf it's always AccelDebugNames, for
// AccelTableKind::Apple, we use the table we got as an argument). If // AccelTableKind::Apple, we use the table we got as an argument). If
// accelerator tables are disabled, this function does nothing. // accelerator tables are disabled, this function does nothing.
template <typename DataT> template <typename DataT>
void DwarfDebug::addAccelNameImpl(const DICompileUnit &CU, void DwarfDebug::addAccelNameImpl(const DICompileUnit &CU,
AccelTable<DataT> &AppleAccel, StringRef Name, AccelTable<DataT> &AppleAccel, StringRef Name,
const DIE &Die) { const DIE &Die) {
if (getAccelTableKind() == AccelTableKind::None) if (getAccelTableKind() == AccelTableKind::None || Name.empty())
return; return;
if (getAccelTableKind() != AccelTableKind::Apple && if (getAccelTableKind() != AccelTableKind::Apple &&
CU.getNameTableKind() != DICompileUnit::DebugNameTableKind::Apple && CU.getNameTableKind() != DICompileUnit::DebugNameTableKind::Apple &&
CU.getNameTableKind() != DICompileUnit::DebugNameTableKind::Default) CU.getNameTableKind() != DICompileUnit::DebugNameTableKind::Default)
return; return;
DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder; DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
▲ Show 20 Lines • Show All 88 Lines • Show Last 20 Lines

llvm/test/DebugInfo/Generic/debug-names-nameless-var.ll

  • This file was added.
; RUN: %llc_dwarf -debugger-tune=lldb -accel-tables=Dwarf -filetype=obj -o %t %s
; RUN: llvm-dwarfdump -debug-names %t | FileCheck %s
; RUN: llvm-dwarfdump -debug-names -verify %t | FileCheck --check-prefix=VERIFY %s
@nameless_var = constant i8 0, !dbg !0
; CHECK: Name count: 0
; VERIFY: No errors
!llvm.dbg.cu = !{!10}
!llvm.module.flags = !{!14, !15}
!llvm.ident = !{!20}
!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
!1 = distinct !DIGlobalVariable(scope: null, file: !11, line: 1, type: !5, isLocal: true, isDefinition: true)
!5 = !DIBasicType(size: 8, encoding: DW_ATE_signed_char)
!10 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !11, producer: "blah", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, globals: !12, splitDebugInlining: false, nameTableKind: Apple, sysroot: "/")
!11 = !DIFile(filename: "blah", directory: "blah")
!12 = !{!0}
!14 = !{i32 7, !"Dwarf Version", i32 5}
!15 = !{i32 2, !"Debug Info Version", i32 3}
!20 = !{!"blah"}