On Wed, Oct 25, 2017 at 10:56 AM, Friedman, Eli <efrie...@codeaurora.org> wrote:
> On 10/6/2017 4:09 PM, Saleem Abdulrasool via cfe-commits wrote: > >> Modified: cfe/trunk/lib/Driver/ToolChains/Clang.cpp >> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Too >> lChains/Clang.cpp?rev=315126&r1=315125&r2=315126&view=diff >> ============================================================ >> ================== >> --- cfe/trunk/lib/Driver/ToolChains/Clang.cpp (original) >> +++ cfe/trunk/lib/Driver/ToolChains/Clang.cpp Fri Oct 6 16:09:55 2017 >> @@ -2601,6 +2601,33 @@ static void RenderModulesOptions(Compila >> Args.AddLastArg(CmdArgs, options::OPT_fmodules_disable_ >> diagnostic_validation); >> } >> +static void RenderCharacterOptions(const ArgList &Args, const >> llvm::Triple &T, >> + ArgStringList &CmdArgs) { >> + // -fsigned-char is default. >> + if (const Arg *A = Args.getLastArg(options::OPT_fsigned_char, >> + options::OPT_fno_signed_char, >> + options::OPT_funsigned_char, >> + options::OPT_fno_unsigned_char)) { >> + if (A->getOption().matches(options::OPT_funsigned_char) || >> + A->getOption().matches(options::OPT_fno_signed_char)) { >> + CmdArgs.push_back("-fno-signed-char"); >> + } >> + } else if (!isSignedCharDefault(T)) { >> + CmdArgs.push_back("-fno-signed-char"); >> + } >> + >> + if (const Arg *A = Args.getLastArg(options::OPT_fshort_wchar, >> + options::OPT_fno_short_wchar)) { >> + if (A->getOption().matches(options::OPT_fshort_wchar)) { >> + CmdArgs.push_back("-fwchar-type=short"); >> + CmdArgs.push_back("-fno-signed-wchar"); >> + } else { >> + CmdArgs.push_back("-fwchar-type=int"); >> + CmdArgs.push_back("-fsigned-wchar"); >> + } >> + } >> +} >> > > It looks like this changes the behavior of "-fno-short-wchar". > Specifically, on targets where the default wchar_t type is "unsigned int" > (like ARM AAPCS), "-fno-short-wchar" used to be a no-op, but now it changes > the sign of wchar_t. Why are we overriding the default here? Overriding the default was more or less the intention, but it was for bitwidth, not signedness. The idea was that if you pass -fno-short-wchar, then you want the 4 byte one. Users probably don't care about signedness when using 4 byte wchars, so we could probably remove the -fsigned-wchar flag from the else block and take the original sign of wchar_t when overriding the width in Basic. They probably want an 'unsigned short' when -fshort-wchar is passed, though.
_______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
