From 2ef4cb9ee0736736daca369d3a3e7da292e0dd54 Mon Sep 17 00:00:00 2001 From: Mehdi Amini Date: Mon, 29 May 2017 06:32:34 +0000 Subject: [PATCH] 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..) Reapply of r304119 after adding a triple to the test and moving it to the X86 directory. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304130 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/AsmPrinter/DIEHash.cpp | 4 +- lib/CodeGen/AsmPrinter/DIEHash.h | 2 +- lib/CodeGen/AsmPrinter/DwarfDebug.cpp | 10 ++++- .../X86/split-dwarf-multiple-cu-hash.ll | 42 +++++++++++++++++++ 4 files changed, 55 insertions(+), 3 deletions(-) create mode 100644 test/DebugInfo/X86/split-dwarf-multiple-cu-hash.ll diff --git a/lib/CodeGen/AsmPrinter/DIEHash.cpp b/lib/CodeGen/AsmPrinter/DIEHash.cpp index ff04ec7f2d7..201030f0ac5 100644 --- a/lib/CodeGen/AsmPrinter/DIEHash.cpp +++ b/lib/CodeGen/AsmPrinter/DIEHash.cpp @@ -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); diff --git a/lib/CodeGen/AsmPrinter/DIEHash.h b/lib/CodeGen/AsmPrinter/DIEHash.h index e2864b17fe2..29337ae38a9 100644 --- a/lib/CodeGen/AsmPrinter/DIEHash.h +++ b/lib/CodeGen/AsmPrinter/DIEHash.h @@ -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); diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp index 06358c42cfe..bf27516e1cc 100644 --- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -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, diff --git a/test/DebugInfo/X86/split-dwarf-multiple-cu-hash.ll b/test/DebugInfo/X86/split-dwarf-multiple-cu-hash.ll new file mode 100644 index 00000000000..f801ade27bd --- /dev/null +++ b/test/DebugInfo/X86/split-dwarf-multiple-cu-hash.ll @@ -0,0 +1,42 @@ +; 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]]) + +target triple = "x86_64-pc-linux" + +; 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)