On Mon, Jul 11, 2016 at 12:19 PM, David Majnemer <david.majne...@gmail.com> wrote:
> > > On Mon, Jul 11, 2016 at 9:03 AM, Nico Weber <tha...@chromium.org> wrote: > >> On Mon, Jul 11, 2016 at 11:51 AM, David Majnemer < >> david.majne...@gmail.com> wrote: >> >>> >>> >>> On Mon, Jul 11, 2016 at 8:42 AM, Nico Weber <tha...@chromium.org> wrote: >>> >>>> On Mon, Jul 11, 2016 at 11:36 AM, David Majnemer < >>>> david.majne...@gmail.com> wrote: >>>> >>>>> >>>>> >>>>> On Mon, Jul 11, 2016 at 7:18 AM, Nico Weber <tha...@chromium.org> >>>>> wrote: >>>>> >>>>>> VS2013's cl.exe doesn't understand /Zd, 2015's doesn't either. This >>>>>> means people who want to ask clang-cl for line tables only will have to >>>>>> add >>>>>> this flag in some if(is_clang) block in their build file anyways. What's >>>>>> the advantage of giving this flag a spelling that's different from both >>>>>> cl >>>>>> and clang? With -gline-tables-only, an if(is_clang) works on Linux, Mac, >>>>>> Windows. >>>>>> >>>>>> (Even if there's a good case for /Zd, I don't think we should remove >>>>>> user-exposed flags without a strong reason, so even if we keep /Zd I >>>>>> think >>>>>> we should also keep exposing -gline-tables-only.) >>>>>> >>>>> >>>>> Existing users of -gline-tables-only? I'd imagine any responsible >>>>> users of -gline-tables-only would probably use their build system to >>>>> verify >>>>> that the flag exists. We have never released an official LLVM which >>>>> supported it (LLVM 3.8 came out in early March and -gline-tables-only was >>>>> exposed via clang-cl in mid March). >>>>> >>>> >>>> Ok, but why is /Zd better than -gline-tables-only? >>>> >>> >>> I see a few reasons: >>> - It is less surprising for a debug flag in the cl world to be called >>> /Zsomething instead of -gsomething. >>> >> >> Eh, you'll have to look it up either way to find the flag. >> > > I agree. > > >> And when seeing the flag, the -g flag is more self-explanatory. >> > > I disagree, I had no idea what that flag did until I started working on > debug info. > > >> Also, it is surprising that a clang-cl /-style flag doesn't work with cl, >> so it just moves the surprise around a bit. >> > > It is surprising when that happens in either direction. If this is > considered a bug, we will never "fix" it. > > >> >> >>> - I think that avoiding invasion of their namespace, when possible, is a >>> good thing. It makes it less likely that we will conflict with a flag they >>> want to add in the future. >>> >> >> I don't understand this point. Doesn't invading their namespace make >> collisions _more_ likely? >> >> >>> - I imagine that if they wanted to add support back for >>> -gline-tables-only, they'd name it /Zd. >>> >> >> Given they had this flag and removed it, they probably didn't like it >> very much :-) >> >> >>> I'm sympathetic to the argument that "-gline-tables-only" is more >>> familiar to Linux/Mac OS X folks and that /Zd won't work across all >>> platforms. >>> >>> Here why I think that's ok: >>> - This is not really a new problem. If you want to select c++1z you get >>> to spell it /std:c++latest for clang-cl and -std=c++14. >>> >> >> Sure, but these are flags that clang/gcc and cl interpret. So if you have >> a gcc build and a visual studio build, it's fairly easy to get each going >> with clang / clang-cl. >> >> With /Zd, we're needlessly inventing a new spelling for an existing clang >> flag. >> > > icl also supports /Zd. > That's a big point in favor of this change, I think. Thanks for pointing it out. > As far as I can see, the new name creates a (small) problem without >> solving one. >> > > This is an attempt to reduce unneeded diversity. > >From my point of view, it increased diversity: Before, this feature had one name, now it has two, and the second name is our own invention. (But if icl also uses that flag, then it's less bad.) > So far, when we wanted to add a flag that cl doesn't have and that clang >> has, we've always gone for the clang spelling of that flag. That seems like >> a good guideline to me. >> > > Often but not always. For example, we have /Qvec instead of -fvectorize > because icl has the flag. > Hm, I'd (weakly) argue that that's not ideal either :-) Anyhow, I think this isn't a good change, and it sounds like you disagree with that. So I guess the next step here is that Hans gets to make a decision once he's back? > > >> >> >>> - People who want harmony between Mac OS X, Linux and Windows on the >>> driver side can just use clang++. >>> >>> >>>> >>>> >>>>> >>>>> I'd consider it in poor form for users to take a hard dependency on a >>>>> flag which only exists in a compiler which has never been released. >>>>> >>>>> I'd agree with you if -gline-tables-only had made its way to an actual >>>>> release. >>>>> >>>>> >>>>>> >>>>>> On Mon, Jul 11, 2016 at 10:08 AM, Nico Weber <tha...@chromium.org> >>>>>> wrote: >>>>>> >>>>>>> This breaks existing users of -gline-tables-only. What's the >>>>>>> motivation for this change? >>>>>>> >>>>>> >>>>>>> On Sat, Jul 9, 2016 at 5:49 PM, David Majnemer via cfe-commits < >>>>>>> cfe-commits@lists.llvm.org> wrote: >>>>>>> >>>>>>>> Author: majnemer >>>>>>>> Date: Sat Jul 9 16:49:16 2016 >>>>>>>> New Revision: 274991 >>>>>>>> >>>>>>>> URL: http://llvm.org/viewvc/llvm-project?rev=274991&view=rev >>>>>>>> Log: >>>>>>>> [clang-cl] Add support for /Zd >>>>>>>> >>>>>>>> MASM (ML.exe and ML64.exe) and older versions of MSVC (CL.exe) >>>>>>>> support a >>>>>>>> flag called /Zd which is more-or-less -gline-tables-only. >>>>>>>> >>>>>>>> It seems nicer to support this flag instead of exposing >>>>>>>> -gline-tables-only. >>>>>>>> >>>>>>>> Modified: >>>>>>>> cfe/trunk/include/clang/Driver/CLCompatOptions.td >>>>>>>> cfe/trunk/include/clang/Driver/Options.td >>>>>>>> cfe/trunk/lib/Driver/Tools.cpp >>>>>>>> cfe/trunk/test/Driver/cl-options.c >>>>>>>> >>>>>>>> Modified: cfe/trunk/include/clang/Driver/CLCompatOptions.td >>>>>>>> URL: >>>>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/CLCompatOptions.td?rev=274991&r1=274990&r2=274991&view=diff >>>>>>>> >>>>>>>> ============================================================================== >>>>>>>> --- cfe/trunk/include/clang/Driver/CLCompatOptions.td (original) >>>>>>>> +++ cfe/trunk/include/clang/Driver/CLCompatOptions.td Sat Jul 9 >>>>>>>> 16:49:16 2016 >>>>>>>> @@ -166,6 +166,8 @@ def _SLASH_Zc_trigraphs_off : CLFlag<"Zc >>>>>>>> HelpText<"Disable trigraphs (default)">, Alias<fno_trigraphs>; >>>>>>>> def _SLASH_Z7 : CLFlag<"Z7">, >>>>>>>> HelpText<"Enable CodeView debug information in object files">; >>>>>>>> +def _SLASH_Zd : CLFlag<"Zd">, >>>>>>>> + HelpText<"Emit debug line number tables only">; >>>>>>>> def _SLASH_Zi : CLFlag<"Zi">, Alias<_SLASH_Z7>, >>>>>>>> HelpText<"Alias for /Z7. Does not produce PDBs.">; >>>>>>>> def _SLASH_Zp : CLJoined<"Zp">, >>>>>>>> >>>>>>>> Modified: cfe/trunk/include/clang/Driver/Options.td >>>>>>>> URL: >>>>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=274991&r1=274990&r2=274991&view=diff >>>>>>>> >>>>>>>> ============================================================================== >>>>>>>> --- cfe/trunk/include/clang/Driver/Options.td (original) >>>>>>>> +++ cfe/trunk/include/clang/Driver/Options.td Sat Jul 9 16:49:16 >>>>>>>> 2016 >>>>>>>> @@ -1229,7 +1229,7 @@ def fdebug_prefix_map_EQ >>>>>>>> def g_Flag : Flag<["-"], "g">, Group<g_Group>, >>>>>>>> HelpText<"Generate source-level debug information">; >>>>>>>> def gline_tables_only : Flag<["-"], "gline-tables-only">, >>>>>>>> Group<gN_Group>, >>>>>>>> - Flags<[CoreOption]>, HelpText<"Emit debug line number tables >>>>>>>> only">; >>>>>>>> + HelpText<"Emit debug line number tables only">; >>>>>>>> def gmlt : Flag<["-"], "gmlt">, Alias<gline_tables_only>; >>>>>>>> def g0 : Flag<["-"], "g0">, Group<gN_Group>; >>>>>>>> def g1 : Flag<["-"], "g1">, Group<gN_Group>, >>>>>>>> Alias<gline_tables_only>; >>>>>>>> >>>>>>>> Modified: cfe/trunk/lib/Driver/Tools.cpp >>>>>>>> URL: >>>>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=274991&r1=274990&r2=274991&view=diff >>>>>>>> >>>>>>>> ============================================================================== >>>>>>>> --- cfe/trunk/lib/Driver/Tools.cpp (original) >>>>>>>> +++ cfe/trunk/lib/Driver/Tools.cpp Sat Jul 9 16:49:16 2016 >>>>>>>> @@ -6269,12 +6269,18 @@ void Clang::AddClangCLArgs(const ArgList >>>>>>>> >>>>>>>> CmdArgs.push_back(Args.MakeArgString(Twine(LangOptions::SSPStrong))); >>>>>>>> } >>>>>>>> >>>>>>>> - // Emit CodeView if -Z7 is present. >>>>>>>> - *EmitCodeView = Args.hasArg(options::OPT__SLASH_Z7); >>>>>>>> - if (*EmitCodeView) >>>>>>>> - *DebugInfoKind = codegenoptions::LimitedDebugInfo; >>>>>>>> - if (*EmitCodeView) >>>>>>>> + // Emit CodeView if -Z7 or -Zd are present. >>>>>>>> + if (Arg *DebugInfoArg = >>>>>>>> + Args.getLastArg(options::OPT__SLASH_Z7, >>>>>>>> options::OPT__SLASH_Zd)) { >>>>>>>> + *EmitCodeView = true; >>>>>>>> + if (DebugInfoArg->getOption().matches(options::OPT__SLASH_Z7)) >>>>>>>> + *DebugInfoKind = codegenoptions::LimitedDebugInfo; >>>>>>>> + else >>>>>>>> + *DebugInfoKind = codegenoptions::DebugLineTablesOnly; >>>>>>>> CmdArgs.push_back("-gcodeview"); >>>>>>>> + } else { >>>>>>>> + *EmitCodeView = false; >>>>>>>> + } >>>>>>>> >>>>>>>> const Driver &D = getToolChain().getDriver(); >>>>>>>> EHFlags EH = parseClangCLEHFlags(D, Args); >>>>>>>> @@ -9964,7 +9970,8 @@ void visualstudio::Linker::ConstructJob( >>>>>>>> >>>>>>>> CmdArgs.push_back("-nologo"); >>>>>>>> >>>>>>>> - if (Args.hasArg(options::OPT_g_Group, options::OPT__SLASH_Z7)) >>>>>>>> + if (Args.hasArg(options::OPT_g_Group, options::OPT__SLASH_Z7, >>>>>>>> + options::OPT__SLASH_Zd)) >>>>>>>> CmdArgs.push_back("-debug"); >>>>>>>> >>>>>>>> bool DLL = Args.hasArg(options::OPT__SLASH_LD, >>>>>>>> options::OPT__SLASH_LDd, >>>>>>>> >>>>>>>> Modified: cfe/trunk/test/Driver/cl-options.c >>>>>>>> URL: >>>>>>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/cl-options.c?rev=274991&r1=274990&r2=274991&view=diff >>>>>>>> >>>>>>>> ============================================================================== >>>>>>>> --- cfe/trunk/test/Driver/cl-options.c (original) >>>>>>>> +++ cfe/trunk/test/Driver/cl-options.c Sat Jul 9 16:49:16 2016 >>>>>>>> @@ -420,7 +420,7 @@ >>>>>>>> // Z7: "-gcodeview" >>>>>>>> // Z7: "-debug-info-kind=limited" >>>>>>>> >>>>>>>> -// RUN: %clang_cl -gline-tables-only /Z7 /c -### -- %s 2>&1 | >>>>>>>> FileCheck -check-prefix=Z7GMLT %s >>>>>>>> +// RUN: %clang_cl /Zd /c -### -- %s 2>&1 | FileCheck >>>>>>>> -check-prefix=Z7GMLT %s >>>>>>>> // Z7GMLT: "-gcodeview" >>>>>>>> // Z7GMLT: "-debug-info-kind=line-tables-only" >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> cfe-commits mailing list >>>>>>>> cfe-commits@lists.llvm.org >>>>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >>>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>> >>>> >>> >> >
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