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. > As far as I can see, the new name creates a (small) problem without > solving one. > This is an attempt to reduce unneeded diversity. > > 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. > > >> - 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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