[clang] [clang] Add /Zc:__STDC__ flag to clang-cl (PR #68690)
via cfe-commits
cfe-commits at lists.llvm.org
Sat Oct 14 02:39:11 PDT 2023
https://github.com/xbjfk updated https://github.com/llvm/llvm-project/pull/68690
>From 92899d94e91a6812de8fa5ec7c15c37a81280108 Mon Sep 17 00:00:00 2001
From: Reagan Bohan <xbjfk.github at gmail.com>
Date: Tue, 10 Oct 2023 11:32:47 +0000
Subject: [PATCH 1/7] [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/include/clang/Basic/LangOptions.def | 2 +-
clang/include/clang/Driver/Options.td | 7 +++++++
clang/lib/Driver/ToolChains/Clang.cpp | 10 +++++++++-
clang/lib/Frontend/InitPreprocessor.cpp | 3 ++-
clang/test/Driver/cl-zc.cpp | 4 ++++
5 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
index c0ea4ecb9806a5b..97101d0166a135a 100644
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -282,7 +282,7 @@ LANGOPT(HIPUseNewLaunchAPI, 1, 0, "Use new kernel launching API for HIP")
LANGOPT(OffloadUniformBlock, 1, 0, "Assume that kernels are launched with uniform block sizes (default true for CUDA/HIP and false otherwise)")
LANGOPT(HIPStdPar, 1, 0, "Enable Standard Parallel Algorithm Acceleration for HIP (experimental)")
LANGOPT(HIPStdParInterposeAlloc, 1, 0, "Replace allocations / deallocations with HIP RT calls when Standard Parallel Algorithm Acceleration for HIP is enabled (Experimental)")
-
+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 c272a7f1c398aa6..fae1dcc2b5117f7 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -2821,6 +2821,10 @@ 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__ 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">,
@@ -7933,6 +7937,9 @@ 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 bfd6c5c2864abf7..2834786ba17decf 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -6744,8 +6744,12 @@ 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");
+ bool IsMSVCDefineStdc = Args.hasArg(options::OPT_fms_define_stdc);
+ if (IsMSVCDefineStdc)
+ CmdArgs.push_back("-fms-define-stdc");
+ }
if (Triple.isWindowsMSVCEnvironment() && !D.IsCLMode() &&
Args.hasArg(options::OPT_fms_runtime_lib_EQ))
@@ -7922,6 +7926,10 @@ void Clang::AddClangCLArgs(const ArgList &Args, types::ID InputType,
CmdArgs.push_back("-fno-wchar");
}
+ if (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 846e5fce6de7b2c..e7ce08a8766d80c 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -423,7 +423,8 @@ 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 c7cf5b1b6525bea..bb955222c647af3 100644
--- a/clang/test/Driver/cl-zc.cpp
+++ b/clang/test/Driver/cl-zc.cpp
@@ -123,6 +123,10 @@
// CHECK-CHAR8_T_: "-fno-char8_t"
+// RUN: %clang_cl /dev/null /E -Xclang -dM 2> /dev/null | FileCheck -match-full-lines %s --check-prefix=STDCOFF
+// RUN: %clang_cl /dev/null /E -Xclang -dM /Zc:__STDC__ 2> /dev/null | FileCheck -match-full-lines %s --check-prefix=STDCON
+// STDCON: #define __STDC__ 1
+// STDCOFF-NOT: #define __STDC__ 1
// These never warn, but don't have an effect yet.
>From ff1dd6421b30d89d8c85465aff8fa826bbc2e097 Mon Sep 17 00:00:00 2001
From: Reagan <xbjfk.github at gmail.com>
Date: Thu, 12 Oct 2023 10:23:50 +0000
Subject: [PATCH 2/7] improve LANGOPT description
Co-authored-by: Aaron Ballman <aaron at aaronballman.com>
---
clang/include/clang/Basic/LangOptions.def | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
index 97101d0166a135a..b170dbd35c7e783 100644
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -282,7 +282,7 @@ LANGOPT(HIPUseNewLaunchAPI, 1, 0, "Use new kernel launching API for HIP")
LANGOPT(OffloadUniformBlock, 1, 0, "Assume that kernels are launched with uniform block sizes (default true for CUDA/HIP and false otherwise)")
LANGOPT(HIPStdPar, 1, 0, "Enable Standard Parallel Algorithm Acceleration for HIP (experimental)")
LANGOPT(HIPStdParInterposeAlloc, 1, 0, "Replace allocations / deallocations with HIP RT calls when Standard Parallel Algorithm Acceleration for HIP is enabled (Experimental)")
-LANGOPT(MSVCEnableStdcMacro , 1, 0, "define __STDC__ with -fms-compatability")
+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")
>From 85d455717e882c06ab53a694e6913e07d9b2dba0 Mon Sep 17 00:00:00 2001
From: Reagan <xbjfk.github at gmail.com>
Date: Thu, 12 Oct 2023 10:24:05 +0000
Subject: [PATCH 3/7] improve help text
Co-authored-by: Aaron Ballman <aaron at aaronballman.com>
---
clang/include/clang/Driver/Options.td | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index fae1dcc2b5117f7..106a1de898764f3 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -2823,7 +2823,7 @@ def fms_compatibility : Flag<["-"], "fms-compatibility">, Group<f_Group>,
MarshallingInfoFlag<LangOpts<"MSVCCompat">>;
def fms_define_stdc : Flag<["-"], "fms-define-stdc">, Group<f_Group>,
Visibility<[ClangOption, CC1Option]>,
- HelpText<"Define __STDC__ in MSVC Compatibility mode">,
+ 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]>,
>From cce2cff7fba0fc567267d2a2bb25477e3e694a12 Mon Sep 17 00:00:00 2001
From: Reagan <xbjfk.github at gmail.com>
Date: Thu, 12 Oct 2023 10:27:53 +0000
Subject: [PATCH 4/7] remove redundant braces
Co-authored-by: Aaron Ballman <aaron at aaronballman.com>
---
clang/lib/Driver/ToolChains/Clang.cpp | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 2834786ba17decf..58aaaa6b6f90dfb 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -7926,9 +7926,8 @@ void Clang::AddClangCLArgs(const ArgList &Args, types::ID InputType,
CmdArgs.push_back("-fno-wchar");
}
- if (Args.hasArg(options::OPT_fms_define_stdc)) {
+ if (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();
>From 97795b1af8108112e1eb23ca778953e203200cb0 Mon Sep 17 00:00:00 2001
From: Reagan Bohan <xbjfk.github at gmail.com>
Date: Thu, 12 Oct 2023 11:44:50 +0000
Subject: [PATCH 5/7] Never define __STDC__ with msvc compat + cxx
---
clang/lib/Driver/ToolChains/Clang.cpp | 7 +++----
clang/test/Driver/cl-zc.cpp | 13 +++++++++----
2 files changed, 12 insertions(+), 8 deletions(-)
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 58aaaa6b6f90dfb..682fa6087237cfa 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -6746,8 +6746,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
options::OPT_fno_ms_extensions, true)));
if (IsMSVCCompat) {
CmdArgs.push_back("-fms-compatibility");
- bool IsMSVCDefineStdc = Args.hasArg(options::OPT_fms_define_stdc);
- if (IsMSVCDefineStdc)
+ if (!types::isCXX(Input.getType()) && Args.hasArg(options::OPT_fms_define_stdc))
CmdArgs.push_back("-fms-define-stdc");
}
@@ -7926,8 +7925,8 @@ void Clang::AddClangCLArgs(const ArgList &Args, types::ID InputType,
CmdArgs.push_back("-fno-wchar");
}
- if (Args.hasArg(options::OPT_fms_define_stdc))
- CmdArgs.push_back("-fms-define-stdc");
+ 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();
diff --git a/clang/test/Driver/cl-zc.cpp b/clang/test/Driver/cl-zc.cpp
index bb955222c647af3..16df6799d5efaa0 100644
--- a/clang/test/Driver/cl-zc.cpp
+++ b/clang/test/Driver/cl-zc.cpp
@@ -123,10 +123,15 @@
// CHECK-CHAR8_T_: "-fno-char8_t"
-// RUN: %clang_cl /dev/null /E -Xclang -dM 2> /dev/null | FileCheck -match-full-lines %s --check-prefix=STDCOFF
-// RUN: %clang_cl /dev/null /E -Xclang -dM /Zc:__STDC__ 2> /dev/null | FileCheck -match-full-lines %s --check-prefix=STDCON
-// STDCON: #define __STDC__ 1
-// STDCOFF-NOT: #define __STDC__ 1
+// 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.
>From 7eba00ccf6dc55a0b165fe81421b4af428174c64 Mon Sep 17 00:00:00 2001
From: Reagan Bohan <xbjfk.github at gmail.com>
Date: Sat, 14 Oct 2023 09:29:03 +0000
Subject: [PATCH 6/7] Add test for invalid args
---
clang/test/Driver/ms-define-stdc.c | 11 +++++++++++
1 file changed, 11 insertions(+)
create mode 100644 clang/test/Driver/ms-define-stdc.c
diff --git a/clang/test/Driver/ms-define-stdc.c b/clang/test/Driver/ms-define-stdc.c
new file mode 100644
index 000000000000000..d5e873d21a76b59
--- /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'
>From fc44ad2bd5fa7d64e12a6656f95abcbf5f6cac99 Mon Sep 17 00:00:00 2001
From: Reagan Bohan <xbjfk.github at gmail.com>
Date: Sat, 14 Oct 2023 09:38:44 +0000
Subject: [PATCH 7/7] Add release note
---
clang/docs/ReleaseNotes.rst | 3 +++
1 file changed, 3 insertions(+)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 2d918967e7f0b02..1932ee0e0661f4e 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -184,6 +184,9 @@ New Compiler Flags
preserving ``#include`` directives for "system" headers instead of copying
the preprocessed text to the output. This can greatly reduce the size of the
preprocessed output, which can be helpful when trying to reduce a test case.
+* ``-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
-------------------------
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