[llvm-branch-commits] [clang] b2de372 - [clang][driver][clang-cl] Support `--precompile` and `-fmodule-*` options in Clang-CL (#98761)
Tobias Hieta via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Sat Aug 10 03:28:48 PDT 2024
Author: Sharadh Rajaraman
Date: 2024-08-10T12:28:36+02:00
New Revision: b2de37237c9ad0b3efafb101c23b075445a6c4ef
URL: https://github.com/llvm/llvm-project/commit/b2de37237c9ad0b3efafb101c23b075445a6c4ef
DIFF: https://github.com/llvm/llvm-project/commit/b2de37237c9ad0b3efafb101c23b075445a6c4ef.diff
LOG: [clang][driver][clang-cl] Support `--precompile` and `-fmodule-*` options in Clang-CL (#98761)
This PR is the first step in improving the situation for `clang-cl`
detailed in [this LLVM Discourse
thread](https://discourse.llvm.org/t/clang-cl-exe-support-for-c-modules/72257/28).
There has been some work done in #89772. I believe this is somewhat
orthogonal.
This is a work-in-progress; the functionality has only been tested with
the [basic 'Hello World'
example](https://clang.llvm.org/docs/StandardCPlusPlusModules.html#quick-start),
and proper test cases need to be written. I'd like some thoughts on
this, thanks!
Partially resolves #64118.
(cherry picked from commit bd576fe34285c4dcd04837bf07a89a9c00e3cd5e)
Added:
clang/test/Driver/cl-cxx20-modules.cppm
Modified:
clang/docs/StandardCPlusPlusModules.rst
clang/docs/UsersManual.rst
clang/include/clang/Driver/Options.td
Removed:
################################################################################
diff --git a/clang/docs/StandardCPlusPlusModules.rst b/clang/docs/StandardCPlusPlusModules.rst
index b87491910e2223..2478a77e7640c5 100644
--- a/clang/docs/StandardCPlusPlusModules.rst
+++ b/clang/docs/StandardCPlusPlusModules.rst
@@ -398,6 +398,16 @@ BMIs cannot be shipped in an archive to create a module library. Instead, the
BMIs(``*.pcm``) are compiled into object files(``*.o``) and those object files
are added to the archive instead.
+clang-cl
+~~~~~~~~
+
+``clang-cl`` supports the same options as ``clang++`` for modules as detailed above;
+there is no need to prefix these options with ``/clang:``. Note that ``cl.exe``
+`options to emit/consume IFC files <https://devblogs.microsoft.com/cppblog/using-cpp-modules-in-msvc-from-the-command-line-part-1/>` are *not* supported.
+The resultant precompiled modules are also not compatible for use with ``cl.exe``.
+
+We recommend that build system authors use the above-mentioned ``clang++`` options with ``clang-cl`` to build modules.
+
Consistency Requirements
~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1387,13 +1397,6 @@ have ``.cppm`` (or ``.ccm``, ``.cxxm``, ``.c++m``) as the file extension.
However, the behavior is inconsistent with other compilers. This is tracked by
`#57416 <https://github.com/llvm/llvm-project/issues/57416>`_.
-clang-cl is not compatible with standard C++ modules
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-``/clang:-fmodule-file`` and ``/clang:-fprebuilt-module-path`` cannot be used
-to specify the BMI with ``clang-cl.exe``. This is tracked by
-`#64118 <https://github.com/llvm/llvm-project/issues/64118>`_.
-
Incorrect ODR violation diagnostics
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
index e9b95739ea2ab5..64e991451bf703 100644
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -4745,6 +4745,12 @@ Execute ``clang-cl /?`` to see a list of supported options:
-flto=<value> Set LTO mode to either 'full' or 'thin'
-flto Enable LTO in 'full' mode
-fmerge-all-constants Allow merging of constants
+ -fmodule-file=<module_name>=<module-file>
+ Use the specified module file that provides the module <module_name>
+ -fmodule-header=<header>
+ Build <header> as a C++20 header unit
+ -fmodule-output=<path>
+ Save intermediate module file results when compiling a standard C++ module unit.
-fms-compatibility-version=<value>
Dot-separated value representing the Microsoft compiler version
number to report in _MSC_VER (0 = don't define it; default is same value as installed cl.exe, or 1933)
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 014a2bd85fdc62..5e412cb5f51894 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -3107,7 +3107,7 @@ def fmodules_user_build_path : Separate<["-"], "fmodules-user-build-path">, Grou
HelpText<"Specify the module user build path">,
MarshallingInfoString<HeaderSearchOpts<"ModuleUserBuildPath">>;
def fprebuilt_module_path : Joined<["-"], "fprebuilt-module-path=">, Group<i_Group>,
- Flags<[]>, Visibility<[ClangOption, CC1Option]>,
+ Flags<[]>, Visibility<[ClangOption, CLOption, CC1Option]>,
MetaVarName<"<directory>">,
HelpText<"Specify the prebuilt module path">;
defm prebuilt_implicit_modules : BoolFOption<"prebuilt-implicit-modules",
@@ -3116,11 +3116,11 @@ defm prebuilt_implicit_modules : BoolFOption<"prebuilt-implicit-modules",
NegFlag<SetFalse>, BothFlags<[], [ClangOption, CC1Option]>>;
def fmodule_output_EQ : Joined<["-"], "fmodule-output=">,
- Flags<[NoXarchOption]>, Visibility<[ClangOption, CC1Option]>,
+ Flags<[NoXarchOption]>, Visibility<[ClangOption, CLOption, CC1Option]>,
MarshallingInfoString<FrontendOpts<"ModuleOutputPath">>,
HelpText<"Save intermediate module file results when compiling a standard C++ module unit.">;
def fmodule_output : Flag<["-"], "fmodule-output">, Flags<[NoXarchOption]>,
- Visibility<[ClangOption, CC1Option]>,
+ Visibility<[ClangOption, CLOption, CC1Option]>,
HelpText<"Save intermediate module file results when compiling a standard C++ module unit.">;
defm skip_odr_check_in_gmf : BoolOption<"f", "skip-odr-check-in-gmf",
@@ -3300,8 +3300,10 @@ def fretain_comments_from_system_headers : Flag<["-"], "fretain-comments-from-sy
Visibility<[ClangOption, CC1Option]>,
MarshallingInfoFlag<LangOpts<"RetainCommentsFromSystemHeaders">>;
def fmodule_header : Flag <["-"], "fmodule-header">, Group<f_Group>,
+ Visibility<[ClangOption, CLOption]>,
HelpText<"Build a C++20 Header Unit from a header">;
def fmodule_header_EQ : Joined<["-"], "fmodule-header=">, Group<f_Group>,
+ Visibility<[ClangOption, CLOption]>,
MetaVarName<"<kind>">,
HelpText<"Build a C++20 Header Unit from a header that should be found in the user (fmodule-header=user) or system (fmodule-header=system) search path.">;
@@ -5946,6 +5948,7 @@ def _output : Separate<["--"], "output">, Alias<o>;
def _param : Separate<["--"], "param">, Group<CompileOnly_Group>;
def _param_EQ : Joined<["--"], "param=">, Alias<_param>;
def _precompile : Flag<["--"], "precompile">, Flags<[NoXarchOption]>,
+ Visibility<[ClangOption, CLOption]>,
Group<Action_Group>, HelpText<"Only precompile the input">;
def _prefix_EQ : Joined<["--"], "prefix=">, Alias<B>;
def _prefix : Separate<["--"], "prefix">, Alias<B>;
diff --git a/clang/test/Driver/cl-cxx20-modules.cppm b/clang/test/Driver/cl-cxx20-modules.cppm
new file mode 100644
index 00000000000000..06df929c42342f
--- /dev/null
+++ b/clang/test/Driver/cl-cxx20-modules.cppm
@@ -0,0 +1,8 @@
+// RUN: %clang_cl /std:c++20 --precompile -### -- %s 2>&1 | FileCheck --check-prefix=PRECOMPILE %s
+// PRECOMPILE: -emit-module-interface
+
+// RUN: %clang_cl /std:c++20 --fmodule-file=Foo=Foo.pcm -### -- %s 2>&1 | FileCheck --check-prefix=FMODULEFILE %s
+// FMODULEFILE: -fmodule-file=Foo=Foo.pcm
+
+// RUN: %clang_cl /std:c++20 --fprebuilt-module-path=. -### -- %s 2>&1 | FileCheck --check-prefix=FPREBUILT %s
+// FPREBUILT: -fprebuilt-module-path=.
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