[llvm] r304119 - DebugInfo: Include .dwo file name when hashing multiple CUs in a single file
Mehdi AMINI via llvm-commits
llvm-commits at lists.llvm.org
Sun May 28 22:18:31 PDT 2017
GreenDragon is broken. Reverted in r304126.
--
Mehdi
2017-05-28 17:48 GMT-07:00 David Blaikie via llvm-commits <
llvm-commits at lists.llvm.org>:
> Author: dblaikie
> Date: Sun May 28 19:48:45 2017
> New Revision: 304119
>
> URL: http://llvm.org/viewvc/llvm-project?rev=304119&view=rev
> Log:
> DebugInfo: Include .dwo file name when hashing multiple CUs in a single
> file
>
> This is really a workaround for ThinLTO in particular - since it can
> import partial CUs that may end up looking very similar/the same as
> the same partial import in another ThinLTO compile.
>
> An alternative fix would be to change the DICompileUnit metadata to
> include a "primary file" or the like - and when importing for ThinLTO
> set the primary file to the name of the DICompileUnit that is being
> imported into. This involves changing the schema and would reduce the
> excessive uniqueness in the hash that this change creates - allowing
> diagnosing of more duplicate CUs than will be caught with this change.
>
> But duplicate CUs can still be caught in non-ThinLTO builds & are mostly
> a nuisance rather than a particularly deliberate/effective tool for
> finding broken code. (arguably the hash could always include the dwo
> file and nothing in fission would break, I think..)
>
> Added:
> llvm/trunk/test/DebugInfo/Generic/split-dwarf-multiple-cu-hash.ll
> Modified:
> llvm/trunk/lib/CodeGen/AsmPrinter/DIEHash.cpp
> llvm/trunk/lib/CodeGen/AsmPrinter/DIEHash.h
> llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DIEHash.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
> CodeGen/AsmPrinter/DIEHash.cpp?rev=304119&r1=304118&r2=304119&view=diff
> ============================================================
> ==================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DIEHash.cpp (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DIEHash.cpp Sun May 28 19:48:45 2017
> @@ -380,10 +380,12 @@ void DIEHash::computeHash(const DIE &Die
> /// DWARF4 standard. It is an md5 hash of the flattened description of
> the DIE
> /// with the inclusion of the full CU and all top level CU entities.
> // TODO: Initialize the type chain at 0 instead of 1 for CU signatures.
> -uint64_t DIEHash::computeCUSignature(const DIE &Die) {
> +uint64_t DIEHash::computeCUSignature(StringRef DWOName, const DIE &Die) {
> Numbering.clear();
> Numbering[&Die] = 1;
>
> + if (!DWOName.empty())
> + Hash.update(DWOName);
> // Hash the DIE.
> computeHash(Die);
>
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DIEHash.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
> CodeGen/AsmPrinter/DIEHash.h?rev=304119&r1=304118&r2=304119&view=diff
> ============================================================
> ==================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DIEHash.h (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DIEHash.h Sun May 28 19:48:45 2017
> @@ -36,7 +36,7 @@ public:
> DIEHash(AsmPrinter *A = nullptr) : AP(A) {}
>
> /// \brief Computes the CU signature.
> - uint64_t computeCUSignature(const DIE &Die);
> + uint64_t computeCUSignature(StringRef DWOName, const DIE &Die);
>
> /// \brief Computes the type signature.
> uint64_t computeTypeSignature(const DIE &Die);
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/
> CodeGen/AsmPrinter/DwarfDebug.cpp?rev=304119&r1=304118&r2=304119&view=diff
> ============================================================
> ==================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Sun May 28 19:48:45
> 2017
> @@ -613,6 +613,13 @@ void DwarfDebug::finalizeModuleInfo() {
>
> finishVariableDefinitions();
>
> + // Include the DWO file name in the hash if there's more than one CU.
> + // This handles ThinLTO's situation where imported CUs may very easily
> be
> + // duplicate with the same CU partially imported into another ThinLTO
> unit.
> + StringRef DWOName;
> + if (CUMap.size() > 1)
> + DWOName = Asm->TM.Options.MCOptions.SplitDwarfFile;
> +
> // Handle anything that needs to be done on a per-unit basis after
> // all other generation.
> for (const auto &P : CUMap) {
> @@ -627,7 +634,8 @@ void DwarfDebug::finalizeModuleInfo() {
> auto *SkCU = TheCU.getSkeleton();
> if (useSplitDwarf()) {
> // Emit a unique identifier for this CU.
> - uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie());
> + uint64_t ID =
> + DIEHash(Asm).computeCUSignature(DWOName, TheCU.getUnitDie());
> TheCU.addUInt(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
> dwarf::DW_FORM_data8, ID);
> SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
>
> Added: llvm/trunk/test/DebugInfo/Generic/split-dwarf-multiple-cu-hash.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
> DebugInfo/Generic/split-dwarf-multiple-cu-hash.ll?rev=304119&view=auto
> ============================================================
> ==================
> --- llvm/trunk/test/DebugInfo/Generic/split-dwarf-multiple-cu-hash.ll
> (added)
> +++ llvm/trunk/test/DebugInfo/Generic/split-dwarf-multiple-cu-hash.ll Sun
> May 28 19:48:45 2017
> @@ -0,0 +1,40 @@
> +; RUN: %llc_dwarf -split-dwarf-file=foo.dwo %s -filetype=obj -o %T/a.o
> +; RUN: %llc_dwarf -split-dwarf-file=bar.dwo %s -filetype=obj -o %T/b.o
> +; RUN: llvm-dwarfdump -debug-dump=info %T/a.o %T/b.o | FileCheck %s
> +
> +; CHECK: dwo_id {{.*}}([[HASH:.*]])
> +; CHECK-NOT: dwo_id {{.*}}([[HASH]])
> +
> +; Function Attrs: noinline nounwind uwtable
> +define void @_Z1av() #0 !dbg !9 {
> +entry:
> + ret void, !dbg !12
> +}
> +
> +; Function Attrs: noinline nounwind uwtable
> +define void @_Z1bv() #0 !dbg !13 {
> +entry:
> + ret void, !dbg !14
> +}
> +
> +attributes #0 = { noinline nounwind uwtable "correctly-rounded-divide-sqrt-fp-math"="false"
> "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-jump-tables"="false"
> "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false"
> "no-trapping-math"="false" "stack-protector-buffer-size"="8"
> "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
> "unsafe-fp-math"="false" "use-soft-float"="false" }
> +
> +!llvm.dbg.cu = !{!0, !3}
> +!llvm.ident = !{!5, !5}
> +!llvm.module.flags = !{!6, !7, !8}
> +
> +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1,
> producer: "clang version 5.0.0 (trunk 304107) (llvm/trunk 304109)",
> isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
> +!1 = !DIFile(filename: "a.cpp", directory: "/usr/local/google/home/
> blaikie/dev/scratch")
> +!2 = !{}
> +!3 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !4,
> producer: "clang version 5.0.0 (trunk 304107) (llvm/trunk 304109)",
> isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
> +!4 = !DIFile(filename: "b.cpp", directory: "/usr/local/google/home/
> blaikie/dev/scratch")
> +!5 = !{!"clang version 5.0.0 (trunk 304107) (llvm/trunk 304109)"}
> +!6 = !{i32 2, !"Dwarf Version", i32 4}
> +!7 = !{i32 2, !"Debug Info Version", i32 3}
> +!8 = !{i32 1, !"wchar_size", i32 4}
> +!9 = distinct !DISubprogram(name: "a", linkageName: "_Z1av", scope: !1,
> file: !1, line: 1, type: !10, isLocal: false, isDefinition: true,
> scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !0,
> variables: !2)
> +!10 = !DISubroutineType(types: !11)
> +!11 = !{null}
> +!12 = !DILocation(line: 2, column: 1, scope: !9)
> +!13 = distinct !DISubprogram(name: "b", linkageName: "_Z1bv", scope: !4,
> file: !4, line: 1, type: !10, isLocal: false, isDefinition: true,
> scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !3,
> variables: !2)
> +!14 = !DILocation(line: 2, column: 1, scope: !13)
>
>
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