[llvm] r349976 - [MC] Enable .file support on COFF and diagnose it on unsupported targets

Fri Dec 28 10:57:34 PST 2018

I moved the directive into the !defined(APPLE) portion in r350132 to fix
the error.

On Thu, Dec 27, 2018 at 5:23 PM Petr Hosek <phosek at chromium.org> wrote:

> This broke our macOS builders when building XRay with the following error:
>
> FAILED:
> compiler-rt/lib/xray/CMakeFiles/RTXray.osx.dir/xray_trampoline_x86_64.S.o
> /b/s/w/ir/kitchen-workdir/recipe_cleanup/clangfJXnpj/llvm_build_dir/./bin/clang
> --target=x86_64-apple-darwin17.7.0 -DXRAY_HAS_EXCEPTIONS=1 -D_DEBUG
> -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS
> -I/b/s/w/ir/kitchen-workdir/llvm-project/compiler-rt/lib/xray/..
> -I/b/s/w/ir/kitchen-workdir/llvm-project/compiler-rt/lib/xray/../../include
> -fPIC -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra
> -Wno-unused-parameter -Wwrite-strings -Wmissing-field-initializers
> -Wimplicit-fallthrough -Wcovered-switch-default -Wdelete-non-virtual-dtor
> -Wstring-conversion -fdiagnostics-color -Wall -Wno-unused-parameter -O3
> -arch x86_64   -UNDEBUG  -stdlib=libc++ -mmacosx-version-min=10.9 -isysroot
> /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.13.sdk
> -fPIC -fno-builtin -fno-exceptions -funwind-tables -fno-stack-protector
> -fno-sanitize=safe-stack -fvisibility=hidden -fno-lto -O3
> -gline-tables-only -Wno-gnu -Wno-variadic-macros -Wno-c99-extensions
> -Wno-non-virtual-dtor -fno-rtti -MD -MT
> compiler-rt/lib/xray/CMakeFiles/RTXray.osx.dir/xray_trampoline_x86_64.S.o
> -MF
> compiler-rt/lib/xray/CMakeFiles/RTXray.osx.dir/xray_trampoline_x86_64.S.o.d
> -o
> compiler-rt/lib/xray/CMakeFiles/RTXray.osx.dir/xray_trampoline_x86_64.S.o
>  -c
> /b/s/w/ir/kitchen-workdir/llvm-project/compiler-rt/lib/xray/xray_trampoline_x86_64.S
> /b/s/w/ir/kitchen-workdir/llvm-project/compiler-rt/lib/xray/xray_trampoline_x86_64.S:97:2:
> error: target does not support '.file' without a number
>  .file "xray_trampoline_x86.S"
>  ^
>
> This has been compiling before so I don't understand why it hasn't crashed
> the compiler like your file-single.s test does. In any case, we probably
> need to change xray_trampoline_x86_64.S or revert this change.
>
> On Fri, Dec 21, 2018 at 3:38 PM Reid Kleckner via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
>
>> Author: rnk
>> Date: Fri Dec 21 15:35:48 2018
>> New Revision: 349976
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=349976&view=rev
>> Log:
>> [MC] Enable .file support on COFF and diagnose it on unsupported targets
>>
>> Summary:
>> The "single parameter" .file directive appears to be an ELF-only feature
>> that is intended to insert the main source filename into the string
>> table table.
>>
>> I noticed that if you assemble an ELF .s file for COFF, typically it
>> will assert right away on a .file directive near the top of the file. My
>> first change was to make this emit a proper error in the asm parser so
>> that we don't assert so easily.
>>
>> However, COFF actually does have some support for this directive, and if
>> you emit an object file, llvm-mc does not assert. When emitting a COFF
>> object, MC will take those file names and create "debug" symbol table
>> entries for them. I'm not familiar with these kinds of symbol table
>> entries, and I'm not aware of any users of them, but @compnerd added
>> them a while ago. They don't introduce absolute paths, and most main
>> source file paths are short enough that this extra entry shouldn't cause
>> any problems, so I enabled the flag in MCAsmInfoCOFF that indicates that
>> it's supported.
>>
>> This has the side effect of adding an extra debug symbol to every object
>> produced by clang, which is a pretty big functional change. My question
>> is, should we keep the functionality or remove it in the name of symbol
>> table minimalism?
>>
>> Reviewers: mstorsjo, compnerd
>>
>> Subscribers: hiraditya, compnerd, llvm-commits
>>
>> Differential Revision: https://reviews.llvm.org/D55900
>>
>> Added:
>>     llvm/trunk/test/MC/MachO/file-single.s
>> Modified:
>>     llvm/trunk/lib/MC/MCAsmInfoCOFF.cpp
>>     llvm/trunk/lib/MC/MCParser/AsmParser.cpp
>>     llvm/trunk/test/MC/COFF/file.s
>>
>> Modified: llvm/trunk/lib/MC/MCAsmInfoCOFF.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCAsmInfoCOFF.cpp?rev=349976&r1=349975&r2=349976&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/lib/MC/MCAsmInfoCOFF.cpp (original)
>> +++ llvm/trunk/lib/MC/MCAsmInfoCOFF.cpp Fri Dec 21 15:35:48 2018
>> @@ -25,7 +25,7 @@ MCAsmInfoCOFF::MCAsmInfoCOFF() {
>>    COMMDirectiveAlignmentIsInBytes = false;
>>    LCOMMDirectiveAlignmentType = LCOMM::ByteAlignment;
>>    HasDotTypeDotSizeDirective = false;
>> -  HasSingleParameterDotFile = false;
>> +  HasSingleParameterDotFile = true;
>>    WeakRefDirective = "\t.weak\t";
>>    HasLinkOnceDirective = true;
>>
>>
>> Modified: llvm/trunk/lib/MC/MCParser/AsmParser.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCParser/AsmParser.cpp?rev=349976&r1=349975&r2=349976&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/lib/MC/MCParser/AsmParser.cpp (original)
>> +++ llvm/trunk/lib/MC/MCParser/AsmParser.cpp Fri Dec 21 15:35:48 2018
>> @@ -3360,9 +3360,12 @@ bool AsmParser::parseDirectiveFile(SMLoc
>>      }
>>    }
>>
>> -  if (FileNumber == -1)
>> +  if (FileNumber == -1) {
>> +    if (!getContext().getAsmInfo()->hasSingleParameterDotFile())
>> +      return Error(DirectiveLoc,
>> +                   "target does not support '.file' without a number");
>>      getStreamer().EmitFileDirective(Filename);
>> -  else {
>> +  } else {
>>      // In case there is a -g option as well as debug info from directive
>> .file,
>>      // we turn off the -g option, directly use the existing debug info
>> instead.
>>      // Also reset any implicit ".file 0" for the assembler source.
>>
>> Modified: llvm/trunk/test/MC/COFF/file.s
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/COFF/file.s?rev=349976&r1=349975&r2=349976&view=diff
>>
>> ==============================================================================
>> --- llvm/trunk/test/MC/COFF/file.s (original)
>> +++ llvm/trunk/test/MC/COFF/file.s Fri Dec 21 15:35:48 2018
>> @@ -1,6 +1,11 @@
>>  // RUN: llvm-mc -triple i686-windows -filetype obj %s -o - |
>> llvm-objdump -t - \
>>  // RUN:   | FileCheck %s
>>
>> +// Round trip through .s output to exercise MCAsmStreamer.
>> +// RUN: llvm-mc -triple i686-windows %s -o - \
>> +// RUN:   | llvm-mc -triple i686-windows - -filetype=obj -o - |
>> llvm-objdump -t - \
>> +// RUN:   | FileCheck %s
>> +
>>  // RUN: llvm-mc -triple i686-windows -filetype obj %s -o - \
>>  // RUN:          | llvm-readobj -symbols | FileCheck %s -check-prefix
>> CHECK-SCN
>>
>>
>> Added: llvm/trunk/test/MC/MachO/file-single.s
>> URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/MachO/file-single.s?rev=349976&view=auto
>>
>> ==============================================================================
>> --- llvm/trunk/test/MC/MachO/file-single.s (added)
>> +++ llvm/trunk/test/MC/MachO/file-single.s Fri Dec 21 15:35:48 2018
>> @@ -0,0 +1,8 @@
>> +// RUN: not llvm-mc -triple i386-apple-darwin9 %s -o /dev/null 2>&1 |
>> FileCheck %s
>> +
>> +// Previously this crashed MC.
>> +
>> +// CHECK: error: target does not support '.file' without a number
>> +
>> +        .file "dir/foo"
>> +        nop
>>
>>
>> _______________________________________________
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>> llvm-commits at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>
>
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