Sorry, I was supposed to chime in here. I don't have a strong opinion on this, but I don't think it's a problem for us to allow the -gline-tables-only spelling in addition to /Zd.
It just doesn't seem like a big deal to me. On Mon, Jul 11, 2016 at 5:50 PM, Saleem Abdulrasool via cfe-commits <cfe-commits@lists.llvm.org> wrote: > On Mon, Jul 11, 2016 at 12:29 PM, David Majnemer via cfe-commits > <cfe-commits@lists.llvm.org> wrote: >> >> >> >> On Mon, Jul 11, 2016 at 12:18 PM, Nico Weber <tha...@chromium.org> wrote: >>> >>> 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.) >> >> >> It's not out invention, it's Microsoft's. icl (and now clang-cl) both >> happen to still support it. If a build system wanted just line table debug >> info for a cl-like driver, they just need /Zd. >> >>> >>> >>>>> >>>>> 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 :-) >> >> >> Why? MSVC has picked up flags from icl. See /Qvec-report. >> >>> >>> >>> 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? >> >> >> More opinions are always better. > > > Well, in that case, my opinion, which arguably may be worthless, is to keep > the /Zd spelling. > > /Zd is meant to only produce line number information (aka, line tables). > Yes, this is different from the clang driver, but if you want to use GCC > style arguments, why are you using the clang-cl frontend? > >>> >>>> >>>> >>>>> >>>>> >>>>>> >>>>>> - 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 >>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>> >>>> >>> >> >> >> _______________________________________________ >> cfe-commits mailing list >> cfe-commits@lists.llvm.org >> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits >> > > > > -- > Saleem Abdulrasool > compnerd (at) compnerd (dot) org > > _______________________________________________ > cfe-commits mailing list > cfe-commits@lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits > _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
