[DebugInfo] Have the verifier accept missing linkage name for anything other than subprograms.

[JDevlieghere]

Summary

According to the standard, for the .debug_names (the "dwarf accelerator tables):

If a subprogram or inlined subroutine is included, and has a DW_AT_linkage_name attribute, there will be an additional index entry for the linkage name.

For Swift we generate DW_structure_types with a linkage name and the verifier was incorrectly rejecting this. This patch fixes that. The test is the "reduced" debug info of the failing swift test on swift.org. If there's a way to generate a smaller test case I'm very much open to suggestions.

[labath]

You are correct that we were being too strict in our requirements here. Though if these structs do have linkage names they could actually be useful (eg as a substitute for the "qualified name hash" in lldb) and we could consider adding them as an extension.

For the test,have you tried writing some dwarf by hand (or more like, modifying an existing .s file to add a linkage name attribute. There should be some .s files in the debug names dumper test suite that can serve as a reasonable starting point)?

[aprantl]

The test seem really long, perhaps try running delta on it using a script that runs dwarfdump | FileChecks on it and checks for the one TAG you are actually interested in?

[aprantl]

Hmm.. no. Because of the offsets that won't work well in assembler. You'd have reduce the llvm IR or source code instead.

[JDevlieghere]

• Reduce test

[JDevlieghere]

ping

[labath]

looks good to me

llvm/trunk/lib/DebugInfo/DWARF/DWARFVerifier.cpp

if (!Attributes.count(dwarf::DW_IDX_die_offset)) {
           "NameIndex @ {0:x}: Abbreviation {1:x} has no {2} attribute.\n",
           NI.getUnitOffset(), Abbrev.Code, dwarf::DW_IDX_die_offset);
       ++NumErrors;
     }
   }
   return NumErrors;
 }
 
-static SmallVector<StringRef, 2> getNames(const DWARFDie &DIE) {
+static SmallVector<StringRef, 2> getNames(const DWARFDie &DIE,
+                                          bool IncludeLinkageName = true) {
   SmallVector<StringRef, 2> Result;
   if (const char *Str = DIE.getName(DINameKind::ShortName))
     Result.emplace_back(Str);
   else if (DIE.getTag() == dwarf::DW_TAG_namespace)
     Result.emplace_back("(anonymous namespace)");
 
+  if (IncludeLinkageName) {
     if (const char *Str = DIE.getName(DINameKind::LinkageName)) {
       if (Result.empty() || Result[0] != Str)
         Result.emplace_back(Str);
     }
+  }
 
   return Result;
 }
 
 unsigned DWARFVerifier::verifyNameIndexEntries(
     const DWARFDebugNames::NameIndex &NI,
     const DWARFDebugNames::NameTableEntry &NTE) {
   // Verifying type unit indexes not supported.
unsigned DWARFVerifier::verifyNameIndexCompleteness(
 
   // "DW_TAG_namespace debugging information entries without a DW_AT_name
   // attribute are included with the name “(anonymous namespace)”.
   // All other debugging information entries without a DW_AT_name attribute
   // are excluded."
   // "If a subprogram or inlined subroutine is included, and has a
   // DW_AT_linkage_name attribute, there will be an additional index entry for
   // the linkage name."
-  auto EntryNames = getNames(Die);
+  auto IncludeLinkageName = Die.getTag() == DW_TAG_subprogram ||
+                            Die.getTag() == DW_TAG_inlined_subroutine;
+  auto EntryNames = getNames(Die, IncludeLinkageName);
   if (EntryNames.empty())
     return 0;
 
   // We deviate from the specification here, which says:
   // "The name index must contain an entry for each debugging information entry
   // that defines a named subprogram, label, variable, type, or namespace,
   // subject to ..."
   // Instead whitelisting all TAGs representing a "type" or a "subprogram", to

llvm/trunk/test/tools/llvm-dwarfdump/X86/verify_no_linkage_name.s

+# This test generates a DW_TAG_structure_type with a linkage name. This linkage
+# name will not be part of the accelerator table and the verifier should not
+# complain about this.
+#
+# DW_TAG_structure_type
+#   DW_AT_name    ("C")
+#   DW_AT_linkage_name    ("$S4main1CCD")
+#
+# RUN: llvm-mc %s -filetype obj -triple x86_64-unknown-linux-gnu -o %t.o
+# RUN: llvm-dwarfdump -debug-info %t.o | FileCheck %s
+# RUN: llvm-dwarfdump -debug-names %t.o | FileCheck %s --check-prefix ACCEL
+# RUN: llvm-dwarfdump -verify -debug-names %t.o
+
+# CHECK: DW_AT_name    ("Bool")
+# CHECK-NEXT: DW_AT_linkage_name    ("$SSbD")
+
+# ACCEL-NOT: String: {{.*}} "$SSbD"
+# ACCEL: String: {{.*}} "Bool"
+# ACCEL-NOT: String: {{.*}} "$SSbD"
+
+  .text
+  .file "local-vars.swift.gyb.tmp.s"
+  .protected  main
+  .globl  main
+  .p2align  4, 0x90
+  .type main,@function
+main:
+.Lfunc_begin0:
+.Ltmp0:
+.Ltmp1:
+.Lfunc_end0:
+.Lfunc_begin1:
+.Ltmp2:
+.Ltmp3:
+.Ltmp4:
+.Lfunc_end1:
+.Lfunc_begin2:
+.Ltmp5:
+.Ltmp6:
+.Ltmp7:
+.Lfunc_end2:
+.Lfunc_begin3:
+.Ltmp8:
+.Ltmp9:
+.Ltmp10:
+.Lfunc_end3:
+.Lfunc_begin4:
+.Ltmp11:
+.Ltmp12:
+.Lfunc_end4:
+.Lfunc_begin5:
+.Ltmp13:
+.LBB5_2:
+.Ltmp14:
+.Lfunc_end5:
+.L__unnamed_1:
+.L__unnamed_2:
+.L__unnamed_3:
+  .section  .swift1_autolink_entries,"a",@progbits
+  .p2align  3
+.L_swift1_autolink_entries:
+  .asciz  "-lswiftSwiftOnoneSupport\000-lswiftCore"
+  .size .L_swift1_autolink_entries, 37
+
+  .section  ".linker-options","e",@llvm_linker_options
+  .section  .debug_str,"MS",@progbits,1
+.Linfo_string0:
+  .asciz  "Swift version 4.2-dev effective-4.1.50 (LLVM a4b1bcaa22, Clang 257fa19143, Swift 836ad071bd)"
+.Linfo_string1:
+  .asciz  "/home/jonas/swift/build/Ninja-RelWithDebInfoAssert/swift-linux-x86_64/test-linux-x86_64/DebugInfo/Output/local-vars.swift.gyb.tmp.swift"
+.Linfo_string2:
+  .asciz  "/home/jonas/swift/build/Ninja-RelWithDebInfoAssert/swift-linux-x86_64/test-linux-x86_64/DebugInfo"
+.Linfo_string3:
+  .asciz  "main"
+.Linfo_string4:
+  .asciz  "/home/jonas/swift/build/Ninja-RelWithDebInfoAssert/swift-linux-x86_64/test-linux-x86_64/DebugInfo/Output"
+.Linfo_string5:
+  .asciz  "Swift"
+.Linfo_string6:
+  .asciz  "/home/jonas/swift/build/Ninja-RelWithDebInfoAssert/swift-linux-x86_64/lib/swift/linux/x86_64/Swift.swiftmodule"
+.Linfo_string7:
+  .asciz  "SwiftOnoneSupport"
+.Linfo_string8:
+  .asciz  "/home/jonas/swift/build/Ninja-RelWithDebInfoAssert/swift-linux-x86_64/lib/swift/linux/x86_64/SwiftOnoneSupport.swiftmodule"
+.Linfo_string9:
+  .asciz  "C"
+.Linfo_string10:
+  .asciz  "$S4main1CCD"
+.Linfo_string11:
+  .asciz  "init"
+.Linfo_string12:
+  .asciz  "$S4main1CCyACSicfc"
+.Linfo_string13:
+  .asciz  "isZero"
+.Linfo_string14:
+  .asciz  "$S4main1CC6isZeroSbyF"
+.Linfo_string15:
+  .asciz  "deinit"
+.Linfo_string16:
+  .asciz  "$S4main1CCfd"
+.Linfo_string17:
+  .asciz  "$S4main1CCfD"
+.Linfo_string18:
+  .asciz  "$S4main1CCMa"
+.Linfo_string19:
+  .asciz  "Int32"
+.Linfo_string20:
+  .asciz  "$Ss5Int32VD"
+.Linfo_string21:
+  .asciz  "Bool"
+.Linfo_string22:
+  .asciz  "$SSbD"
+.Linfo_string23:
+  .asciz  "$SBoD"
+.Linfo_string24:
+  .asciz  "$SytD"
+.Linfo_string25:
+  .asciz  "i"
+.Linfo_string26:
+  .asciz  "Int"
+.Linfo_string27:
+  .asciz  "$SSiD"
+.Linfo_string28:
+  .asciz  "self"
+  .section  .debug_abbrev,"",@progbits
+  .byte 1
+  .byte 17
+  .byte 1
+  .byte 37
+  .byte 14
+  .byte 19
+  .byte 5
+  .byte 3
+  .byte 14
+  .byte 16
+  .byte 23
+  .byte 27
+  .byte 14
+  .ascii  "\345\177"
+  .byte 11
+  .byte 17
+  .byte 1
+  .byte 18
+  .byte 6
+  .byte 0
+  .byte 0
+  .byte 2
+  .byte 30
+  .byte 1
+  .byte 3
+  .byte 14
+  .ascii  "\200|"
+  .byte 14
+  .byte 0
+  .byte 0
+  .byte 3
+  .byte 46
+  .byte 0
+  .byte 17
+  .byte 1
+  .byte 18
+  .byte 6
+  .byte 64
+  .byte 24
+  .byte 110
+  .byte 14
+  .byte 3
+  .byte 14
+  .byte 58
+  .byte 11
+  .byte 59
+  .byte 11
+  .byte 73
+  .byte 19
+  .byte 63
+  .byte 25
+  .byte 0
+  .byte 0
+  .byte 4
+  .byte 19
+  .byte 1
+  .byte 3
+  .byte 14
+  .byte 110
+  .byte 14
+  .byte 11
+  .byte 11
+  .byte 58
+  .byte 11
+  .byte 59
+  .byte 11
+  .ascii  "\346\177"
+  .byte 11
+  .byte 0
+  .byte 0
+  .byte 5
+  .byte 46
+  .byte 1
+  .byte 17
+  .byte 1
+  .byte 18
+  .byte 6
+  .byte 64
+  .byte 24
+  .byte 110
+  .byte 14
+  .byte 3
+  .byte 14
+  .byte 58
+  .byte 11
+  .byte 59
+  .byte 11
+  .byte 73
+  .byte 19
+  .byte 63
+  .byte 25
+  .byte 0
+  .byte 0
+  .byte 6
+  .byte 5
+  .byte 0
+  .byte 2
+  .byte 24
+  .byte 3
+  .byte 14
+  .byte 58
+  .byte 11
+  .byte 59
+  .byte 11
+  .byte 73
+  .byte 19
+  .byte 0
+  .byte 0
+  .byte 7
+  .byte 5
+  .byte 0
+  .byte 2
+  .byte 24
+  .byte 3
+  .byte 14
+  .byte 58
+  .byte 11
+  .byte 59
+  .byte 11
+  .byte 73
+  .byte 19
+  .byte 52
+  .byte 25
+  .byte 0
+  .byte 0
+  .byte 8
+  .byte 46
+  .byte 0
+  .byte 17
+  .byte 1
+  .byte 18
+  .byte 6
+  .byte 64
+  .byte 24
+  .byte 110
+  .byte 14
+  .byte 52
+  .byte 25
+  .byte 63
+  .byte 25
+  .byte 0
+  .byte 0
+  .byte 9
+  .byte 58
+  .byte 0
+  .byte 24
+  .byte 19
+  .byte 0
+  .byte 0
+  .byte 10
+  .byte 19
+  .byte 0
+  .byte 3
+  .byte 14
+  .byte 110
+  .byte 14
+  .byte 11
+  .byte 11
+  .ascii  "\346\177"
+  .byte 11
+  .byte 0
+  .byte 0
+  .byte 11
+  .byte 30
+  .byte 0
+  .byte 3
+  .byte 14
+  .ascii  "\200|"
+  .byte 14
+  .byte 0
+  .byte 0
+  .byte 12
+  .byte 15
+  .byte 0
+  .byte 3
+  .byte 14
+  .byte 0
+  .byte 0
+  .byte 0
+  .section  .debug_info,"",@progbits
+.Lcu_begin0:
+  .long 385
+  .short  4
+  .long .debug_abbrev
+  .byte 8
+  .byte 1
+  .long .Linfo_string0
+  .short  30
+  .long .Linfo_string1
+  .long .Lline_table_start0
+  .long .Linfo_string2
+  .byte 4
+  .quad .Lfunc_begin0
+  .long .Lfunc_end5-.Lfunc_begin0
+  .byte 2
+  .long .Linfo_string3
+  .long .Linfo_string4
+  .byte 3
+  .quad .Lfunc_begin0
+  .long .Lfunc_end0-.Lfunc_begin0
+  .byte 1
+  .byte 86
+  .long .Linfo_string3
+  .long .Linfo_string3
+  .byte 1
+  .byte 1
+  .long 319
+
+  .byte 4
+  .long .Linfo_string9
+  .long .Linfo_string10
+  .byte 8
+  .byte 1
+  .byte 9
+  .byte 30
+  .byte 5
+  .quad .Lfunc_begin1
+  .long .Lfunc_end1-.Lfunc_begin1
+  .byte 1
+  .byte 86
+  .long .Linfo_string12
+  .long .Linfo_string11
+  .byte 1
+  .byte 11
+  .long 81
+
+  .byte 6
+  .byte 2
+  .byte 145
+  .byte 120
+  .long .Linfo_string25
+  .byte 1
+  .byte 11
+  .long 341
+  .byte 7
+  .byte 2
+  .byte 145
+  .byte 112
+  .long .Linfo_string28
+  .byte 1
+  .byte 11
+  .long 81
+
+  .byte 0
+  .byte 5
+  .quad .Lfunc_begin2
+  .long .Lfunc_end2-.Lfunc_begin2
+  .byte 1
+  .byte 86
+  .long .Linfo_string14
+  .long .Linfo_string13
+  .byte 1
+  .byte 12
+  .long 330
+
+  .byte 7
+  .byte 2
+  .byte 145
+  .byte 112
+  .long .Linfo_string28
+  .byte 1
+  .byte 12
+  .long 81
+
+  .byte 0
+  .byte 5
+  .quad .Lfunc_begin3
+  .long .Lfunc_end3-.Lfunc_begin3
+  .byte 1
+  .byte 86
+  .long .Linfo_string16
+  .long .Linfo_string15
+  .byte 1
+  .byte 9
+  .long 372
+
+  .byte 7
+  .byte 2
+  .byte 145
+  .byte 120
+  .long .Linfo_string28
+  .byte 1
+  .byte 9
+  .long 81
+
+  .byte 0
+  .byte 5
+  .quad .Lfunc_begin4
+  .long .Lfunc_end4-.Lfunc_begin4
+  .byte 1
+  .byte 86
+  .long .Linfo_string17
+  .long .Linfo_string15
+  .byte 1
+  .byte 9
+  .long 377
+
+  .byte 7
+  .byte 2
+  .byte 145
+  .byte 120
+  .long .Linfo_string28
+  .byte 1
+  .byte 9
+  .long 81
+
+  .byte 0
+  .byte 0
+  .byte 8
+  .quad .Lfunc_begin5
+  .long .Lfunc_end5-.Lfunc_begin5
+  .byte 1
+  .byte 86
+  .long .Linfo_string18
+
+
+  .byte 0
+  .byte 9
+  .long 43
+  .byte 2
+  .long .Linfo_string5
+  .long .Linfo_string6
+  .byte 10
+  .long .Linfo_string19
+  .long .Linfo_string20
+  .byte 4
+  .byte 30
+  .byte 10
+  .long .Linfo_string21
+  .long .Linfo_string22
+  .byte 1
+  .byte 30
+  .byte 10
+  .long .Linfo_string26
+  .long .Linfo_string27
+  .byte 8
+  .byte 30
+  .byte 0
+  .byte 9
+  .long 310
+  .byte 11
+  .long .Linfo_string7
+  .long .Linfo_string8
+  .byte 9
+  .long 358
+  .byte 12
+  .long .Linfo_string23
+  .byte 10
+  .long .Linfo_string24
+  .long .Linfo_string24
+  .byte 0
+  .byte 30
+  .byte 0
+  .section  .debug_ranges,"",@progbits
+  .section  .debug_macinfo,"",@progbits
+  .byte 0
+  .section  .debug_names,"",@progbits
+  .long .Lnames_end0-.Lnames_start0
+.Lnames_start0:
+  .short  5
+  .short  0
+  .long 1
+  .long 0
+  .long 0
+  .long 14
+  .long 15
+  .long .Lnames_abbrev_end0-.Lnames_abbrev_start0
+  .long 8
+  .ascii  "LLVM0700"
+  .long .Lcu_begin0
+  .long 0
+  .long 0
+  .long 1
+  .long 0
+  .long 2
+  .long 0
+  .long 0
+  .long 4
+  .long 6
+  .long 7
+  .long 11
+  .long 14
+  .long 15
+  .long 0
+  .long -125696958
+  .long -1434607370
+  .long -1434607370
+  .long 87184321
+  .long 2090120081
+  .long -1434607142
+  .long 181113837
+  .long 262755061
+  .long 2090370361
+  .long -1008003439
+  .long 193495088
+  .long 2090499946
+  .long -1294887406
+  .long 181088625
+  .long 177672
+  .long .Linfo_string15
+  .long .Linfo_string16
+  .long .Linfo_string17
+  .long .Linfo_string13
+  .long .Linfo_string21
+  .long .Linfo_string18
+  .long .Linfo_string24
+  .long .Linfo_string19
+  .long .Linfo_string11
+  .long .Linfo_string12
+  .long .Linfo_string26
+  .long .Linfo_string3
+  .long .Linfo_string14
+  .long .Linfo_string23
+  .long .Linfo_string9
+  .long .Lnames14-.Lnames_entries0
+  .long .Lnames9-.Lnames_entries0
+  .long .Lnames10-.Lnames_entries0
+  .long .Lnames13-.Lnames_entries0
+  .long .Lnames7-.Lnames_entries0
+  .long .Lnames12-.Lnames_entries0
+  .long .Lnames2-.Lnames_entries0
+  .long .Lnames8-.Lnames_entries0
+  .long .Lnames11-.Lnames_entries0
+  .long .Lnames5-.Lnames_entries0
+  .long .Lnames3-.Lnames_entries0
+  .long .Lnames1-.Lnames_entries0
+  .long .Lnames6-.Lnames_entries0
+  .long .Lnames4-.Lnames_entries0
+  .long .Lnames0-.Lnames_entries0
+.Lnames_abbrev_start0:
+  .byte 46
+  .byte 46
+  .byte 3
+  .byte 19
+  .byte 0
+  .byte 0
+  .byte 15
+  .byte 15
+  .byte 3
+  .byte 19
+  .byte 0
+  .byte 0
+  .byte 19
+  .byte 19
+  .byte 3
+  .byte 19
+  .byte 0
+  .byte 0
+  .byte 0
+.Lnames_abbrev_end0:
+.Lnames_entries0:
+.Lnames14:
+  .byte 46
+  .long 196
+  .byte 46
+  .long 240
+  .long 0
+.Lnames9:
+  .byte 46
+  .long 196
+  .long 0
+.Lnames10:
+  .byte 46
+  .long 240
+  .long 0
+.Lnames13:
+  .byte 46
+  .long 152
+  .long 0
+.Lnames7:
+  .byte 19
+  .long 330
+  .long 0
+.Lnames12:
+  .byte 46
+  .long 285
+  .long 0
+.Lnames2:
+  .byte 19
+  .long 377
+  .long 0
+.Lnames8:
+  .byte 19
+  .long 319
+  .long 0
+.Lnames11:
+  .byte 46
+  .long 94
+  .long 0
+.Lnames5:
+  .byte 46
+  .long 94
+  .long 0
+.Lnames3:
+  .byte 19
+  .long 341
+  .long 0
+.Lnames1:
+  .byte 46
+  .long 52
+  .long 0
+.Lnames6:
+  .byte 46
+  .long 152
+  .long 0
+.Lnames4:
+  .byte 15
+  .long 372
+  .long 0
+.Lnames0:
+  .byte 19
+  .long 81
+  .long 0
+  .p2align  2
+.Lnames_end0:
+
+  .globl  $S4main1CCN
+  .protected  $S4main1CCN
+.set $S4main1CCN, ($S4main1CCMf)+16
+  .section  .debug_line,"",@progbits
+.Lline_table_start0: