[llvm] r358931 - DebugInfo: Emit only one kind of accelerated access/name table

Tue Apr 23 11:43:52 PDT 2019

Hmm, so that's curious. At least when I target darwin from linux (& it
looks like this'd be the same regardless of host) the Clang driver
passes -ggnu-pubnames down, and so the IR ends up with DICompileUnit's
nameTableKind:GNU. And looking at the resulting objects they have both
apple_names and gnu_pubnames and pubtypes.

Adrian - do you see that too? Is that the case, that Apple platforms
are getting what would appear to be by accident,
debug_gnu_pubnames/pubtypes?

(that's a driver/frontend issue - and, yeah, regardless of whether
that bug happens, LLVM still shouldn't respect the nameTableKind if
LLVM's emitting apple names - because Apple names can't support a
missing CU, it has to cover all the CUs in the object. So I have a fix
for that bit, and need some test coverage. But I feel like there's a
frontend bug for Apple platforms too)

On Tue, Apr 23, 2019 at 8:18 AM Adrian Prantl <aprantl at apple.com> wrote:
>
> Thanks! Let me know if you need any help with the analysis.
>
> -- adrian
>
> > On Apr 23, 2019, at 8:02 AM, David Blaikie <dblaikie at gmail.com> wrote:
> >
> > (oops, this time on-list)
> >
> > Yep, I can observe a change in size of apple_names under this patch.
> > Reverted in r358997 while I investigate.
> >
> > On Mon, Apr 22, 2019 at 7:11 PM Adrian Prantl <aprantl at apple.com> wrote:
> >>
> >> I haven't tried to reproduce the failure yet, but do you think it's possible this caused the debuginfo-tests to fail?
> >>
> >> http://lab.llvm.org:8080/green/job/clang-stage1-configure-RA/55815/
> >>
> >> It seems to be the only non-NFC change in the blamelist.
> >>
> >> -- adrian
> >>
> >> On Apr 22, 2019, at 3:45 PM, David Blaikie via llvm-commits <llvm-commits at lists.llvm.org> wrote:
> >>
> >> Author: dblaikie
> >> Date: Mon Apr 22 15:45:11 2019
> >> New Revision: 358931
> >>
> >> URL: http://llvm.org/viewvc/llvm-project?rev=358931&view=rev
> >> Log:
> >> DebugInfo: Emit only one kind of accelerated access/name table
> >>
> >> Currently to opt in to debug_names in DWARFv5, the IR must contain
> >> 'nameTableKind: Default' which also enables debug_pubnames.
> >>
> >> Instead, only allow one of {debug_names, apple_names, debug_pubnames,
> >> debug_gnu_pubnames}.
> >>
> >> nameTableKind: Default gives debug_names in DWARFv5 and greater,
> >> debug_pubnames in v4 and earlier - and apple_names when tuning for lldb
> >> on MachO.
> >> nameTableKind: GNU always gives gnu_pubnames
> >>
> >> Added:
> >>   llvm/trunk/test/DebugInfo/X86/gnu-names.ll
> >>     - copied, changed from r358805, llvm/trunk/test/DebugInfo/X86/accel-tables.ll
> >> Modified:
> >>   llvm/trunk/lib/CodeGen/AsmPrinter/AccelTable.cpp
> >>   llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
> >>   llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
> >>   llvm/trunk/test/DebugInfo/X86/accel-tables.ll
> >>
> >> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/AccelTable.cpp
> >> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/AccelTable.cpp?rev=358931&r1=358930&r2=358931&view=diff
> >> ==============================================================================
> >> --- llvm/trunk/lib/CodeGen/AsmPrinter/AccelTable.cpp (original)
> >> +++ llvm/trunk/lib/CodeGen/AsmPrinter/AccelTable.cpp Mon Apr 22 15:45:11 2019
> >> @@ -556,8 +556,8 @@ void llvm::emitDWARF5AccelTable(
> >>  SmallVector<unsigned, 1> CUIndex(CUs.size());
> >>  int Count = 0;
> >>  for (const auto &CU : enumerate(CUs)) {
> >> -    if (CU.value()->getCUNode()->getNameTableKind() ==
> >> -        DICompileUnit::DebugNameTableKind::None)
> >> +    if (CU.value()->getCUNode()->getNameTableKind() !=
> >> +        DICompileUnit::DebugNameTableKind::Default)
> >>      continue;
> >>    CUIndex[CU.index()] = Count++;
> >>    assert(CU.index() == CU.value()->getUniqueID());
> >>
> >> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
> >> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp?rev=358931&r1=358930&r2=358931&view=diff
> >> ==============================================================================
> >> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp (original)
> >> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp Mon Apr 22 15:45:11 2019
> >> @@ -1036,7 +1036,9 @@ bool DwarfCompileUnit::hasDwarfPubSectio
> >>    return true;
> >>  case DICompileUnit::DebugNameTableKind::Default:
> >>    return DD->tuneForGDB() && !includeMinimalInlineScopes() &&
> >> -           !CUNode->isDebugDirectivesOnly();
> >> +           !CUNode->isDebugDirectivesOnly() &&
> >> +           DD->getAccelTableKind() != AccelTableKind::Apple &&
> >> +           DD->getDwarfVersion() < 5;
> >>  }
> >>  llvm_unreachable("Unhandled DICompileUnit::DebugNameTableKind enum");
> >> }
> >>
> >> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
> >> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=358931&r1=358930&r2=358931&view=diff
> >> ==============================================================================
> >> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
> >> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Mon Apr 22 15:45:11 2019
> >> @@ -2765,6 +2765,9 @@ void DwarfDebug::addAccelNameImpl(const
> >>      CU.getNameTableKind() == DICompileUnit::DebugNameTableKind::None)
> >>    return;
> >>
> >> +  if (CU.getNameTableKind() == DICompileUnit::DebugNameTableKind::GNU)
> >> +    return;
> >> +
> >>  DwarfFile &Holder = useSplitDwarf() ? SkeletonHolder : InfoHolder;
> >>  DwarfStringPoolEntryRef Ref = Holder.getStringPool().getEntry(*Asm, Name);
> >>
> >>
> >> Modified: llvm/trunk/test/DebugInfo/X86/accel-tables.ll
> >> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/accel-tables.ll?rev=358931&r1=358930&r2=358931&view=diff
> >> ==============================================================================
> >> --- llvm/trunk/test/DebugInfo/X86/accel-tables.ll (original)
> >> +++ llvm/trunk/test/DebugInfo/X86/accel-tables.ll Mon Apr 22 15:45:11 2019
> >> @@ -4,11 +4,11 @@
> >> ; RUN: llc -mtriple=x86_64-apple-darwin12 -filetype=obj < %s \
> >> ; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=APPLE %s
> >> ; RUN: llc -mtriple=x86_64-apple-darwin12 -filetype=obj -debugger-tune=gdb < %s \
> >> -; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=NONE %s
> >> +; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=PUB %s
> >>
> >> ; Linux does has debug_names tables only if we explicitly tune for lldb
> >> ; RUN: llc -mtriple=x86_64-pc-linux -filetype=obj < %s \
> >> -; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=NONE %s
> >> +; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=PUB %s
> >> ; RUN: llc -mtriple=x86_64-pc-linux -filetype=obj -debugger-tune=lldb < %s \
> >> ; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=DEBUG_NAMES %s
> >>
> >> @@ -23,15 +23,25 @@
> >> ; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=APPLE %s
> >>
> >> ; APPLE-NOT: debug_names
> >> +; APPLE-NOT: pubnames
> >> ; APPLE: apple_names
> >> ; APPLE-NOT: debug_names
> >> +; APPLE-NOT: pubnames
> >> +
> >> +; PUB-NOT: apple_names
> >> +; PUB-NOT: debug_names
> >> +; PUB: pubnames
> >> +; PUB-NOT: apple_names
> >> +; PUB-NOT: debug_names
> >>
> >> ; NONE-NOT: apple_names
> >> ; NONE-NOT: debug_names
> >>
> >> ; DEBUG_NAMES-NOT: apple_names
> >> +; DEBUG_NAMES-NOT: pubnames
> >> ; DEBUG_NAMES: debug_names
> >> ; DEBUG_NAMES-NOT: apple_names
> >> +; DEBUG_NAMES-NOT: pubnames
> >>
> >> @var = thread_local global i32 0, align 4, !dbg !0
> >>
> >>
> >> Copied: llvm/trunk/test/DebugInfo/X86/gnu-names.ll (from r358805, llvm/trunk/test/DebugInfo/X86/accel-tables.ll)
> >> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/gnu-names.ll?p2=llvm/trunk/test/DebugInfo/X86/gnu-names.ll&p1=llvm/trunk/test/DebugInfo/X86/accel-tables.ll&r1=358805&r2=358931&rev=358931&view=diff
> >> ==============================================================================
> >> --- llvm/trunk/test/DebugInfo/X86/accel-tables.ll (original)
> >> +++ llvm/trunk/test/DebugInfo/X86/gnu-names.ll Mon Apr 22 15:45:11 2019
> >> @@ -4,13 +4,13 @@
> >> ; RUN: llc -mtriple=x86_64-apple-darwin12 -filetype=obj < %s \
> >> ; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=APPLE %s
> >> ; RUN: llc -mtriple=x86_64-apple-darwin12 -filetype=obj -debugger-tune=gdb < %s \
> >> -; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=NONE %s
> >> +; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=GNU %s
> >>
> >> ; Linux does has debug_names tables only if we explicitly tune for lldb
> >> ; RUN: llc -mtriple=x86_64-pc-linux -filetype=obj < %s \
> >> -; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=NONE %s
> >> +; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=GNU %s
> >> ; RUN: llc -mtriple=x86_64-pc-linux -filetype=obj -debugger-tune=lldb < %s \
> >> -; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=DEBUG_NAMES %s
> >> +; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=GNU %s
> >>
> >> ; No accelerator tables if type units are enabled, as DWARF v4 type units are
> >> ; not compatible with accelerator tables.
> >> @@ -23,16 +23,20 @@
> >> ; RUN:   | llvm-readobj -sections - | FileCheck --check-prefix=APPLE %s
> >>
> >> ; APPLE-NOT: debug_names
> >> +; APPLE-NOT: pubnames
> >> ; APPLE: apple_names
> >> ; APPLE-NOT: debug_names
> >> +; APPLE-NOT: pubnames
> >> +
> >> +; GNU-NOT: apple_names
> >> +; GNU-NOT: debug_names
> >> +; GNU: gnu_pub
> >> +; GNU-NOT: apple_names
> >> +; GNU-NOT: debug_names
> >>
> >> ; NONE-NOT: apple_names
> >> ; NONE-NOT: debug_names
> >>
> >> -; DEBUG_NAMES-NOT: apple_names
> >> -; DEBUG_NAMES: debug_names
> >> -; DEBUG_NAMES-NOT: apple_names
> >> -
> >> @var = thread_local global i32 0, align 4, !dbg !0
> >>
> >> ; Function Attrs: norecurse nounwind readnone uwtable
> >> @@ -54,7 +58,7 @@ attributes #1 = { norecurse uwtable }
> >>
> >> !0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
> >> !1 = distinct !DIGlobalVariable(name: "var", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true)
> >> -!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 7.0.0 (trunk 322268) (llvm/trunk 322267)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
> >> +!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 7.0.0 (trunk 322268) (llvm/trunk 322267)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: GNU)
> >> !3 = !DIFile(filename: "debugger-tune.cpp", directory: "/tmp")
> >> !4 = !{}
> >> !5 = !{!0}
> >>
> >>
> >> _______________________________________________
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> >> llvm-commits at lists.llvm.org
> >> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
> >>
> >>
>