https://github.com/xbjfk updated https://github.com/llvm/llvm-project/pull/68690
>From adfced08cd4c150b02345629e1bd9c5bc4681f09 Mon Sep 17 00:00:00 2001 From: Reagan Bohan <xbjfk.git...@gmail.com> Date: Sun, 10 Mar 2024 01:49:37 +0000 Subject: [PATCH] [clang] Add /Zc:__STDC__ flag to clang-cl This commit adds the /Zc:__STDC__ argument from MSVC, which defines __STDC__. This means, alongside stronger feature parity with MSVC, that things that rely on __STDC__, such as autoconf, can work. --- clang/docs/ReleaseNotes.rst | 3 +++ clang/include/clang/Basic/LangOptions.def | 1 + clang/include/clang/Driver/Options.td | 7 +++++++ clang/lib/Driver/ToolChains/Clang.cpp | 9 ++++++++- clang/lib/Frontend/InitPreprocessor.cpp | 3 ++- clang/test/Driver/cl-zc.cpp | 9 +++++++++ clang/test/Driver/ms-define-stdc.c | 11 +++++++++++ 7 files changed, 41 insertions(+), 2 deletions(-) create mode 100644 clang/test/Driver/ms-define-stdc.c diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 3b89d5a8720785..fde603a6245247 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -177,6 +177,9 @@ New Compiler Flags - ``-Wmissing-designated-field-initializers``, grouped under ``-Wmissing-field-initializers``. This diagnostic can be disabled to make ``-Wmissing-field-initializers`` behave like it did before Clang 18.x. Fixes (`#56628 <https://github.com/llvm/llvm-project/issues/68933>`_) +- ``-fms-define-stdc`` and its clang-cl counterpart ``/Zc:__STDC__``. + Matches MSVC behaviour by defining ``__STDC__`` to ``1`` when + MSVC compatibility mode is used. It has no effect for C++ code. Deprecated Compiler Flags ------------------------- diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def index 472fd9f093a718..121db13277b474 100644 --- a/clang/include/clang/Basic/LangOptions.def +++ b/clang/include/clang/Basic/LangOptions.def @@ -291,6 +291,7 @@ LANGOPT(HIPStdParInterposeAlloc, 1, 0, "Replace allocations / deallocations with LANGOPT(OpenACC , 1, 0, "OpenACC Enabled") +LANGOPT(MSVCEnableStdcMacro , 1, 0, "Define __STDC__ with '-fms-compatability'") LANGOPT(SizedDeallocation , 1, 0, "sized deallocation") LANGOPT(AlignedAllocation , 1, 0, "aligned allocation") LANGOPT(AlignedAllocationUnavailable, 1, 0, "aligned allocation functions are unavailable") diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index aca8c9b0d5487a..7a24f26530c60f 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -2934,6 +2934,10 @@ def fms_compatibility : Flag<["-"], "fms-compatibility">, Group<f_Group>, Visibility<[ClangOption, CC1Option, CLOption]>, HelpText<"Enable full Microsoft Visual C++ compatibility">, MarshallingInfoFlag<LangOpts<"MSVCCompat">>; +def fms_define_stdc : Flag<["-"], "fms-define-stdc">, Group<f_Group>, + Visibility<[ClangOption, CC1Option]>, + HelpText<"Define '__STDC__' to '1' in MSVC Compatibility mode">, + MarshallingInfoFlag<LangOpts<"MSVCEnableStdcMacro">>; def fms_extensions : Flag<["-"], "fms-extensions">, Group<f_Group>, Visibility<[ClangOption, CC1Option, CLOption]>, HelpText<"Accept some non-standard constructs supported by the Microsoft compiler">, @@ -8172,6 +8176,9 @@ def _SLASH_vd : CLJoined<"vd">, HelpText<"Control vtordisp placement">, Alias<vtordisp_mode_EQ>; def _SLASH_X : CLFlag<"X">, HelpText<"Do not add %INCLUDE% to include search path">, Alias<nostdlibinc>; +def _SLASH_Zc___STDC__ : CLFlag<"Zc:__STDC__">, + HelpText<"Define __STDC__">, + Alias<fms_define_stdc>; def _SLASH_Zc_sizedDealloc : CLFlag<"Zc:sizedDealloc">, HelpText<"Enable C++14 sized global deallocation functions">, Alias<fsized_deallocation>; diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index cc568b9a715bbe..f9e2cb043f7b5d 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -6888,8 +6888,12 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, options::OPT_fms_compatibility, options::OPT_fno_ms_compatibility, (IsWindowsMSVC && Args.hasFlag(options::OPT_fms_extensions, options::OPT_fno_ms_extensions, true))); - if (IsMSVCCompat) + if (IsMSVCCompat) { CmdArgs.push_back("-fms-compatibility"); + if (!types::isCXX(Input.getType()) && + Args.hasArg(options::OPT_fms_define_stdc)) + CmdArgs.push_back("-fms-define-stdc"); + } if (Triple.isWindowsMSVCEnvironment() && !D.IsCLMode() && Args.hasArg(options::OPT_fms_runtime_lib_EQ)) @@ -8065,6 +8069,9 @@ void Clang::AddClangCLArgs(const ArgList &Args, types::ID InputType, CmdArgs.push_back("-fno-wchar"); } + if (!types::isCXX(InputType) && Args.hasArg(options::OPT_fms_define_stdc)) + CmdArgs.push_back("-fms-define-stdc"); + if (Args.hasArg(options::OPT__SLASH_kernel)) { llvm::Triple::ArchType Arch = getToolChain().getArch(); std::vector<std::string> Values = diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp index 48ad92063bd461..f3315a1d9a8b74 100644 --- a/clang/lib/Frontend/InitPreprocessor.cpp +++ b/clang/lib/Frontend/InitPreprocessor.cpp @@ -433,7 +433,8 @@ static void InitializeStandardPredefinedMacros(const TargetInfo &TI, // [C++] Whether __STDC__ is predefined and if so, what its value is, // are implementation-defined. // (Removed in C++20.) - if (!LangOpts.MSVCCompat && !LangOpts.TraditionalCPP) + if ((!LangOpts.MSVCCompat || LangOpts.MSVCEnableStdcMacro) && + !LangOpts.TraditionalCPP) Builder.defineMacro("__STDC__"); // -- __STDC_HOSTED__ // The integer literal 1 if the implementation is a hosted diff --git a/clang/test/Driver/cl-zc.cpp b/clang/test/Driver/cl-zc.cpp index c7cf5b1b6525be..16df6799d5efaa 100644 --- a/clang/test/Driver/cl-zc.cpp +++ b/clang/test/Driver/cl-zc.cpp @@ -123,6 +123,15 @@ // CHECK-CHAR8_T_: "-fno-char8_t" +// RUN: %clang_cl /TC /dev/null /E -Xclang -dM 2> /dev/null | FileCheck -match-full-lines %s --check-prefix=NOSTDC +// RUN: %clang_cl /TC /dev/null /E -Xclang -dM /Zc:__STDC__ 2> /dev/null | FileCheck -match-full-lines %s --check-prefix=YESSTDC +// __STDC__ should never be defined in C++ mode with fms-compatibility. +// RUN: %clang_cl /dev/null /E -Xclang -dM 2>&1 | FileCheck %s --check-prefix=NOSTDC +// RUN: %clang_cl /dev/null /E -Xclang -dM /Zc:__STDC__ 2>&1 | FileCheck %s --check-prefix=ZCSTDCIGNORED +// YESSTDC: #define __STDC__ 1 +// NOSTDC-NOT: #define __STDC__ 1 +// ZCSTDCIGNORED-NOT: #define __STDC__ 1 +// ZCSTDCIGNORED: argument unused during compilation // These never warn, but don't have an effect yet. diff --git a/clang/test/Driver/ms-define-stdc.c b/clang/test/Driver/ms-define-stdc.c new file mode 100644 index 00000000000000..d5e873d21a76b5 --- /dev/null +++ b/clang/test/Driver/ms-define-stdc.c @@ -0,0 +1,11 @@ +// Note: %s must be preceded by --, otherwise it may be interpreted as a +// command-line option, e.g. on Mac where %s is commonly under /Users. +// +// Note: see also cl-zc.cpp + +// RUN: %clang_cl /TC /dev/null /E -Xclang -dM /Zc:__STDC__- 2>&1 | FileCheck %s --check-prefix=ZCSTDCIGNORED +// ZCSTDCIGNORED-NOT: #define __STDC__ 1 +// ZCSTDCIGNORED: argument unused during compilation + +// RUN: not %clang -Xclang -fno-ms-define-stdc %s 2>&1 | FileCheck %s --check-prefix="NOARG" +// NOARG: error: unknown argument: '-fno-ms-define-stdc' _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits