[llvm] r249487 - DebugInfo: Include the decl_line/decl_file in subprogram definitions if they differ from those in the declaration
David Blaikie via llvm-commits
llvm-commits at lists.llvm.org
Wed Oct 7 09:25:51 PDT 2015
On Wed, Oct 7, 2015 at 9:17 AM, David Blaikie <dblaikie at gmail.com> wrote:
>
>
> On Wed, Oct 7, 2015 at 9:07 AM, Robinson, Paul <
> Paul_Robinson at playstation.sony.com> wrote:
>
>> Resending because reply-all didn't cc llvm-commits...
>>
>> > -----Original Message-----
>> > From: llvm-commits [mailto:llvm-commits-bounces at lists.llvm.org] On
>> Behalf
>> > Of David Blaikie via llvm-commits
>> > Sent: Tuesday, October 06, 2015 5:04 PM
>> > To: llvm-commits at lists.llvm.org
>> > Subject: [llvm] r249487 - DebugInfo: Include the decl_line/decl_file in
>> > subprogram definitions if they differ from those in the declaration
>> >
>> > Author: dblaikie
>> > Date: Tue Oct 6 19:04:16 2015
>> > New Revision: 249487
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=249487&view=rev
>> > Log:
>> > DebugInfo: Include the decl_line/decl_file in subprogram definitions if
>> > they differ from those in the declaration
>> >
>> > This is handy for some AutoFDO stuff, and seems like a minor improvement
>> > to correctness (otherwise a debug info consumer might think the decl
>> > line/file of the def was the same as that of the declaration - though
>> > what a consumer might use that for, I'm not sure - maybe "list <func>"
>> > would've misbehaved with the old behavior?) and at a minor cost (in my
>> > experiment, with fission, without type units, without compression, 0.01%
>> > growth in debug info in the executable/objects, 0.02% growth in the .dwo
>> > files).
>> >
>> > Added:
>> > llvm/trunk/test/DebugInfo/Generic/def-line.ll
>> > Modified:
>> > llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
>> > llvm/trunk/test/DebugInfo/X86/concrete_out_of_line.ll
>> > llvm/trunk/test/DebugInfo/X86/dwarf-public-names.ll
>> >
>> > Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
>> > URL: http://llvm.org/viewvc/llvm-
>> >
>> project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp?rev=249487&r1=2494
>> > 86&r2=249487&view=diff
>> >
>> ==========================================================================
>> > ====
>> > --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp (original)
>> > +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp Tue Oct 6 19:04:16
>> > 2015
>> > @@ -1151,6 +1151,14 @@ bool DwarfUnit::applySubprogramDefinitio
>> > "definition DIE was created in "
>> > "getOrCreateSubprogramDIE");
>> > DeclLinkageName = SPDecl->getLinkageName();
>> > + unsigned DeclID =
>> > + getOrCreateSourceID(SPDecl->getFilename(), SPDecl-
>> > >getDirectory());
>> > + unsigned DefID = getOrCreateSourceID(SP->getFilename(), SP-
>> > >getDirectory());
>> > + if (DeclID != DefID)
>> > + addUInt(SPDie, dwarf::DW_AT_decl_file, None, DefID);
>> > +
>> > + if (SP->getLine() != SPDecl->getLine())
>> > + addUInt(SPDie, dwarf::DW_AT_decl_line, None, SP->getLine());
>>
>> Please emit both together, not potentially just one or the other.
>> (Based on the Principle of Least Surprise; these attributes are
>> commonly considered a pair, even if it is syntactically legal to
>> provide only one or the other.)
>>
>
> I think that would be a mistake - the way that DW_AT_specification is
> specified is similar to entities with DW_AT_abstract_origin - the idea
> being that most attributes are inherited from the declaration to the
> definition, except where the definition overrides them. (the wording is a
> bit vague about which things should be considered inherited and which
> should not - it provides some examples of obvious things not to inherit,
> and then basically leaves it up to the implementation, it seems)
>
Oh, and GCC already does this (not sure for how long it's been doing it - I
imagine for a while, given the way one might implement it to naturally
collapse matching attribute values between decl and def) so there's some
precedent for consumers being able to cope with it.
I imagine you have a specific problem, though, with the PS4 debugger not
being able to cope with this?
>
> Again, it's not a huge size growth, and including both or neither might
> reduce the abbrev growth slightly (less variety in abbrevs) so it's not a
> technical difficulty, just a philosophical one.
>
> - Dave
>
>
>> --paulr
>>
>> > }
>> >
>> > // Add function template parameters.
>> >
>> > Added: llvm/trunk/test/DebugInfo/Generic/def-line.ll
>> > URL: http://llvm.org/viewvc/llvm-
>> >
>> project/llvm/trunk/test/DebugInfo/Generic/def-line.ll?rev=249487&view=auto
>> >
>> ==========================================================================
>> > ====
>> > --- llvm/trunk/test/DebugInfo/Generic/def-line.ll (added)
>> > +++ llvm/trunk/test/DebugInfo/Generic/def-line.ll Tue Oct 6 19:04:16
>> 2015
>> > @@ -0,0 +1,95 @@
>> > +; REQUIRES: object-emission
>> > +
>> > +; RUN: %llc_dwarf < %s -filetype=obj | llvm-dwarfdump -debug-dump=info
>> -
>> > | FileCheck %s
>> > +
>> > +; Given the following source, ensure that the decl_line/file is
>> correctly
>> > +; emitted and omitted on definitions if it mismatches/matches the
>> > declaration
>> > +
>> > +; struct foo {
>> > +; static void f1() {
>> > +; }
>> > +; static void f2();
>> > +; static void f3();
>> > +; };
>> > +; void foo::f2() {
>> > +; f1(); // just to ensure f1 is emitted
>> > +; }
>> > +; #line 1 "bar.cpp"
>> > +; void foo::f3() {
>> > +; }
>> > +
>> > +; Skip the declarations
>> > +; CHECK: DW_TAG_subprogram
>> > +; CHECK: DW_TAG_subprogram
>> > +; CHECK: DW_TAG_subprogram
>> > +
>> > +; CHECK: DW_TAG_subprogram
>> > +; CHECK-NOT: {{DW_TAG|NULL|DW_AT_decl_file}}
>> > +; CHECK: DW_AT_decl_line {{.*}}7
>> > +; CHECK-NOT: {{DW_TAG|NULL|DW_AT_decl_file}}
>> > +; CHECK: DW_AT_specification {{.*}}f2
>> > +; CHECK-NOT: {{DW_TAG|NULL|DW_AT_decl_file}}
>> > +
>> > +; CHECK: DW_TAG_subprogram
>> > +; CHECK-NOT: {{DW_TAG|NULL|DW_AT_decl_line|DW_AT_decl_file}}
>> > +; CHECK: DW_AT_specification {{.*}}f1
>> > +
>> > +; CHECK: DW_TAG_subprogram
>> > +; CHECK-NOT: {{DW_TAG|NULL}}
>> > +; CHECK: DW_AT_decl_file {{.*}}bar.cpp
>> > +; CHECK-NOT: {{DW_TAG|NULL}}
>> > +; CHECK: DW_AT_decl_line {{.*}}1
>> > +; CHECK-NOT: {{DW_TAG|NULL}}
>> > +; CHECK: DW_AT_specification {{.*}}f3
>> > +
>> > +$_ZN3foo2f1Ev = comdat any
>> > +
>> > +; Function Attrs: uwtable
>> > +define void @_ZN3foo2f2Ev() #0 align 2 {
>> > +entry:
>> > + call void @_ZN3foo2f1Ev(), !dbg !19
>> > + ret void, !dbg !20
>> > +}
>> > +
>> > +; Function Attrs: nounwind uwtable
>> > +define linkonce_odr void @_ZN3foo2f1Ev() #1 comdat align 2 {
>> > +entry:
>> > + ret void, !dbg !21
>> > +}
>> > +
>> > +; Function Attrs: nounwind uwtable
>> > +define void @_ZN3foo2f3Ev() #1 align 2 {
>> > +entry:
>> > + ret void, !dbg !22
>> > +}
>> > +
>> > +attributes #0 = { uwtable "disable-tail-calls"="false" "less-precise-
>> > fpmad"="false" "no-frame-pointer-elim"="true"
>> "no-frame-pointer-elim-non-
>> > leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-
>> > protector-buffer-size"="8" "target-cpu"="x86-64" "target-
>> > features"="+sse,+sse2" "unsafe-fp-math"="false"
>> "use-soft-float"="false" }
>> > +attributes #1 = { nounwind uwtable "disable-tail-calls"="false" "less-
>> > precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-
>> > elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false"
>> "stack-
>> > protector-buffer-size"="8" "target-cpu"="x86-64" "target-
>> > features"="+sse,+sse2" "unsafe-fp-math"="false"
>> "use-soft-float"="false" }
>> > +
>> > +!llvm.dbg.cu = !{!0}
>> > +!llvm.module.flags = !{!16, !17}
>> > +!llvm.ident = !{!18}
>> > +
>> > +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1,
>> > producer: "clang version 3.8.0 (trunk 249440) (llvm/trunk 249465)",
>> > isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2,
>> > retainedTypes: !3, subprograms: !11)
>> > +!1 = !DIFile(filename: "def-line.cpp", directory: "/tmp/dbginfo")
>> > +!2 = !{}
>> > +!3 = !{!4}
>> > +!4 = !DICompositeType(tag: DW_TAG_structure_type, name: "foo", file:
>> !1,
>> > line: 1, size: 8, align: 8, elements: !5, identifier: "_ZTS3foo")
>> > +!5 = !{!6, !9, !10}
>> > +!6 = !DISubprogram(name: "f1", linkageName: "_ZN3foo2f1Ev", scope:
>> > !"_ZTS3foo", file: !1, line: 2, type: !7, isLocal: false, isDefinition:
>> > false, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false)
>> > +!7 = !DISubroutineType(types: !8)
>> > +!8 = !{null}
>> > +!9 = !DISubprogram(name: "f2", linkageName: "_ZN3foo2f2Ev", scope:
>> > !"_ZTS3foo", file: !1, line: 4, type: !7, isLocal: false, isDefinition:
>> > false, scopeLine: 4, flags: DIFlagPrototyped, isOptimized: false)
>> > +!10 = !DISubprogram(name: "f3", linkageName: "_ZN3foo2f3Ev", scope:
>> > !"_ZTS3foo", file: !1, line: 5, type: !7, isLocal: false, isDefinition:
>> > false, scopeLine: 5, flags: DIFlagPrototyped, isOptimized: false)
>> > +!11 = !{!12, !13, !15}
>> > +!12 = distinct !DISubprogram(name: "f2", linkageName: "_ZN3foo2f2Ev",
>> > scope: !"_ZTS3foo", file: !1, line: 7, type: !7, isLocal: false,
>> > isDefinition: true, scopeLine: 7, flags: DIFlagPrototyped, isOptimized:
>> > false, function: void ()* @_ZN3foo2f2Ev, declaration: !9, variables: !2)
>> > +!13 = distinct !DISubprogram(name: "f3", linkageName: "_ZN3foo2f3Ev",
>> > scope: !"_ZTS3foo", file: !14, line: 1, type: !7, isLocal: false,
>> > isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized:
>> > false, function: void ()* @_ZN3foo2f3Ev, declaration: !10, variables:
>> !2)
>> > +!14 = !DIFile(filename: "bar.cpp", directory: "/tmp/dbginfo")
>> > +!15 = distinct !DISubprogram(name: "f1", linkageName: "_ZN3foo2f1Ev",
>> > scope: !"_ZTS3foo", file: !1, line: 2, type: !7, isLocal: false,
>> > isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized:
>> > false, function: void ()* @_ZN3foo2f1Ev, declaration: !6, variables: !2)
>> > +!16 = !{i32 2, !"Dwarf Version", i32 4}
>> > +!17 = !{i32 2, !"Debug Info Version", i32 3}
>> > +!18 = !{!"clang version 3.8.0 (trunk 249440) (llvm/trunk 249465)"}
>> > +!19 = !DILocation(line: 8, column: 3, scope: !12)
>> > +!20 = !DILocation(line: 9, column: 1, scope: !12)
>> > +!21 = !DILocation(line: 3, column: 3, scope: !15)
>> > +!22 = !DILocation(line: 2, column: 1, scope: !13)
>> >
>> > Modified: llvm/trunk/test/DebugInfo/X86/concrete_out_of_line.ll
>> > URL: http://llvm.org/viewvc/llvm-
>> >
>> project/llvm/trunk/test/DebugInfo/X86/concrete_out_of_line.ll?rev=249487&r
>> > 1=249486&r2=249487&view=diff
>> >
>> ==========================================================================
>> > ====
>> > --- llvm/trunk/test/DebugInfo/X86/concrete_out_of_line.ll (original)
>> > +++ llvm/trunk/test/DebugInfo/X86/concrete_out_of_line.ll Tue Oct 6
>> > 19:04:16 2015
>> > @@ -18,12 +18,14 @@
>> > ; CHECK: DW_AT_name {{.*}} "~nsAutoRefCnt"
>> >
>> > ; CHECK: DW_TAG_subprogram
>> > +; CHECK-NEXT: DW_AT_decl_line {{.*}}18
>> > ; CHECK-NEXT: DW_AT_{{.*}}linkage_name {{.*}}D2
>> > ; CHECK-NEXT: DW_AT_specification {{.*}} "~nsAutoRefCnt"
>> > ; CHECK-NEXT: DW_AT_inline
>> > ; CHECK-NOT: DW_AT
>> > ; CHECK: DW_TAG
>> > ; CHECK: DW_TAG_subprogram
>> > +; CHECK-NEXT: DW_AT_decl_line {{.*}}18
>> > ; CHECK-NEXT: DW_AT_{{.*}}linkage_name {{.*}}D1
>> > ; CHECK-NEXT: DW_AT_specification {{.*}} "~nsAutoRefCnt"
>> > ; CHECK-NEXT: DW_AT_inline
>> >
>> > Modified: llvm/trunk/test/DebugInfo/X86/dwarf-public-names.ll
>> > URL: http://llvm.org/viewvc/llvm-
>> > project/llvm/trunk/test/DebugInfo/X86/dwarf-public-
>> > names.ll?rev=249487&r1=249486&r2=249487&view=diff
>> >
>> ==========================================================================
>> > ====
>> > --- llvm/trunk/test/DebugInfo/X86/dwarf-public-names.ll (original)
>> > +++ llvm/trunk/test/DebugInfo/X86/dwarf-public-names.ll Tue Oct 6
>> > 19:04:16 2015
>> > @@ -43,7 +43,7 @@
>> >
>> > ; Skip the output to the header of the pubnames section.
>> > ; LINUX: debug_pubnames
>> > -; LINUX-NEXT: unit_size = 0x00000128
>> > +; LINUX-NEXT: unit_size = 0x0000012a
>> >
>> > ; Check for each name in the output.
>> > ; LINUX-DAG: "ns"
>> >
>> >
>> > _______________________________________________
>> > llvm-commits mailing list
>> > llvm-commits at lists.llvm.org
>> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>
>
>
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