diff options
| -rw-r--r-- | clang/lib/Driver/Tools.cpp | 25 | ||||
| -rw-r--r-- | clang/test/Driver/clang_f_opts.c | 2 |
2 files changed, 19 insertions, 8 deletions
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp index 524247fe341..dd72fd748ee 100644 --- a/clang/lib/Driver/Tools.cpp +++ b/clang/lib/Driver/Tools.cpp @@ -2677,13 +2677,24 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, Args.AddLastArg(CmdArgs, options::OPT_trigraphs); } - // Map the bizarre '-Wwrite-strings' flag to a more sensible - // '-fconst-strings'; this better indicates its actual behavior. - if (Args.hasFlag(options::OPT_Wwrite_strings, options::OPT_Wno_write_strings, - false)) { - // For perfect compatibility with GCC, we do this even in the presence of - // '-w'. This flag names something other than a warning for GCC. - CmdArgs.push_back("-fconst-strings"); + // GCC's behavior for -Wwrite-strings is a bit strange: + // * In C, this "warning flag" changes the types of string literals from + // 'char[N]' to 'const char[N]', and thus triggers an unrelated warning + // for the discarded qualifier. + // * In C++, this is just a normal warning flag. + // + // Implementing this warning correctly in C is hard, so we follow GCC's + // behavior for now. FIXME: Directly diagnose uses of a string literal as + // a non-const char* in C, rather than using this crude hack. + if (!types::isCXX(InputType)) { + // FIXME: This should behave just like a warning flag, and thus should also + // respect -Weverything, -Wno-everything, -Werror=write-strings, and so on. + Arg *WriteStrings = + Args.getLastArg(options::OPT_Wwrite_strings, + options::OPT_Wno_write_strings, options::OPT_w); + if (WriteStrings && + WriteStrings->getOption().matches(options::OPT_Wwrite_strings)) + CmdArgs.push_back("-fconst-strings"); } // GCC provides a macro definition '__DEPRECATED' when -Wdeprecated is active diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c index 0cf4cc910b2..780b727de05 100644 --- a/clang/test/Driver/clang_f_opts.c +++ b/clang/test/Driver/clang_f_opts.c @@ -19,7 +19,7 @@ // RUN: %clang -### -S -Wwrite-strings -Wno-write-strings %s 2>&1 | FileCheck -check-prefix=WRITE-STRINGS2 %s // WRITE-STRINGS2-NOT: -fconst-strings // RUN: %clang -### -S -Wwrite-strings -w %s 2>&1 | FileCheck -check-prefix=WRITE-STRINGS3 %s -// WRITE-STRINGS3: -fconst-strings +// WRITE-STRINGS3-NOT: -fconst-strings // RUN: %clang -### -x c++ -c %s 2>&1 | FileCheck -check-prefix=DEPRECATED-ON-CHECK %s // RUN: %clang -### -x c++ -c -Wdeprecated %s 2>&1 | FileCheck -check-prefix=DEPRECATED-ON-CHECK %s |
