r263429 - [Frontend] Disable value name discarding for all sanitizers.

[Evgenii Stepanov via cfe-commits]

On Mon, Mar 14, 2016 at 8:48 AM, Benjamin Kramer <benny.kra at gmail.com> wrote:
> On Mon, Mar 14, 2016 at 3:59 PM, David Blaikie <dblaikie at gmail.com> wrote:
>> Yeah - how are they relying on them in a non-asserts build anyway? (were we
>> naming certain things regardless of +/-Asserts? (well, I know we were naming
>> some things, but mostly down in LLVM, I thought Clang generally used the
>> IRBuilder & thus didn't name things in non-Asserts builds))
>
> Allocas used to always have names as a debugging feature, see r246991.
>
>> On Mon, Mar 14, 2016 at 6:36 AM, Chandler Carruth via cfe-commits
>> <cfe-commits at lists.llvm.org> wrote:
>>>
>>> A long time ago I argued that the sanitizers should be using debug info
>>> instead of alloca names for this, and I really thought that they had
>>> implemented this... Is that not the case?
>>>
>>> It is really bad that the sanitizers are relying on this stuff...

We've never implemented this though I think Alexey looked into it at
one point. We'd need to refactor the handling of debug options
(-g/-gline-tables-only) so that debug metadata is emitted with ASan
even without -g and then discarded in the backend.

>>>
>>> On Mon, Mar 14, 2016 at 2:28 PM Benjamin Kramer via cfe-commits
>>> <cfe-commits at lists.llvm.org> wrote:
>>>>
>>>> Author: d0k
>>>> Date: Mon Mar 14 08:23:58 2016
>>>> New Revision: 263429
>>>>
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=263429&view=rev
>>>> Log:
>>>> [Frontend] Disable value name discarding for all sanitizers.
>>>>
>>>> ASan also relies on names on allocas and will emit unhelpful output if
>>>> they're not present. Just force-enable value names for now. Should
>>>> unbreak release builds of asan.
>>>>
>>>> Modified:
>>>>     cfe/trunk/lib/Frontend/CompilerInvocation.cpp
>>>>
>>>> Modified: cfe/trunk/lib/Frontend/CompilerInvocation.cpp
>>>> URL:
>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInvocation.cpp?rev=263429&r1=263428&r2=263429&view=diff
>>>>
>>>> ==============================================================================
>>>> --- cfe/trunk/lib/Frontend/CompilerInvocation.cpp (original)
>>>> +++ cfe/trunk/lib/Frontend/CompilerInvocation.cpp Mon Mar 14 08:23:58
>>>> 2016
>>>> @@ -541,6 +541,7 @@ static bool ParseCodeGenArgs(CodeGenOpti
>>>>    Opts.DisableFPElim =
>>>>        (Args.hasArg(OPT_mdisable_fp_elim) || Args.hasArg(OPT_pg));
>>>>    Opts.DisableFree = Args.hasArg(OPT_disable_free);
>>>> +  Opts.DiscardValueNames = Args.hasArg(OPT_discard_value_names);
>>>>    Opts.DisableTailCalls = Args.hasArg(OPT_mdisable_tail_calls);
>>>>    Opts.FloatABI = Args.getLastArgValue(OPT_mfloat_abi);
>>>>    if (Arg *A = Args.getLastArg(OPT_meabi)) {
>>>> @@ -793,12 +794,6 @@ static bool ParseCodeGenArgs(CodeGenOpti
>>>>    Opts.CudaGpuBinaryFileNames =
>>>>        Args.getAllArgValues(OPT_fcuda_include_gpubinary);
>>>>
>>>> -  // DiscardValueNames is set here so that it can depend (perhaps
>>>> temporarily)
>>>> -  // on other options.
>>>> -  // We check SanitizeMemoryTrackOrigins here because the backend pass
>>>> depends
>>>> -  // on the name of the alloca in order to print out names.
>>>> -  Opts.DiscardValueNames =
>>>> -      Args.hasArg(OPT_discard_value_names) &&
>>>> !Opts.SanitizeMemoryTrackOrigins;
>>>>    return Success;
>>>>  }
>>>>
>>>> @@ -2158,6 +2153,12 @@ bool CompilerInvocation::CreateFromArgs(
>>>>      if (Res.getFrontendOpts().ProgramAction == frontend::RewriteObjC)
>>>>        Res.getLangOpts()->ObjCExceptions = 1;
>>>>    }
>>>> +
>>>> +  // FIXME: Override value name discarding when sanitizers are used
>>>> because the
>>>> +  // backend passes depend on the name of the alloca in order to print
>>>> out
>>>> +  // names.
>>>> +  Res.getCodeGenOpts().DiscardValueNames &=
>>>> Res.getLangOpts()->Sanitize.empty();
>>>> +
>>>>    // FIXME: ParsePreprocessorArgs uses the FileManager to read the
>>>> contents of
>>>>    // PCH file and find the original header name. Remove the need to do
>>>> that in
>>>>    // ParsePreprocessorArgs and remove the FileManager
>>>>
>>>>
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>>>
>>>
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>>