Merge branch 'clang-cl' into 'master'

giscanner: Add support for using clang-cl

See merge request GNOME/gobject-introspection!234

3 files changed, 39 insertions, 6 deletions

diff --git a/MSVC.README.rst b/MSVC.README.rst
index d8941de4..ec5ddb56 100644
--- a/MSVC.README.rst
+++ b/MSVC.README.rst
@@ -109,3 +109,12 @@ the following so that we ensure the manifests are embedded to the built DLLs and
 
   for /r %f in (*.dll.manifest) do if exist $(PREFIX)\bin\%~nf mt /manifest %f /outputresource:$(PREFIX)\bin\%~nf;2
   for /r %f in (*.exe.manifest) do if exist $(PREFIX)\bin\%~nf mt /manifest %f /outputresource:$(PREFIX)\bin\%~nf;1
+
+Additional notes on using clang-cl (LLVM/CLang's Visual Studio compiler emulation)
+----------------------------------------------------------------------------------
+Support has been added to build GObject-Introspection with clang-cl, specifically for
+running g-ir-scanner with clang-cl and lld-link as the compiler and linker.  To enable
+such support, you need to set *both* the environment variables CC and CXX to clang-cl
+prior to building GObject-Introspection or running g-ir-scanner.  This is in line with
+building with clang-cl in place of using the stock Visual Studio compiler to perform
+builds with the Meson build system.
diff --git a/giscanner/ccompiler.py b/giscanner/ccompiler.py
index a81d4b86..bd1aa78e 100644
--- a/giscanner/ccompiler.py
+++ b/giscanner/ccompiler.py
@@ -163,9 +163,11 @@ class CCompiler(object):
                 elif os.environ.get('VCInstallDir'):
                     os.environ['MSSdk'] = os.environ.get('VCInstallDir')
 
-            self.compiler_cmd = 'cl.exe'
-
-            self._cflags_no_deprecation_warnings = "-wd4996"
+            if self.compiler.check_is_clang_cl():
+                self.compiler_cmd = os.environ.get('CC').split()[0]
+            else:
+                self.compiler_cmd = 'cl.exe'
+                self._cflags_no_deprecation_warnings = "-wd4996"
         else:
             if (isinstance(self.compiler, Mingw32CCompiler)):
                 self.compiler_cmd = self.compiler.compiler[0]
@@ -263,7 +265,7 @@ class CCompiler(object):
         # Define these macros when using Visual C++ to silence many warnings,
         # and prevent stepping on many Visual Studio-specific items, so that
         # we don't have to handle them specifically in scannerlexer.l
-        if self.check_is_msvc():
+        if self.check_is_msvc() and not self.compiler.check_is_clang_cl():
             macros.append(('_USE_DECLSPECS_FOR_SAL', None))
             macros.append(('_CRT_SECURE_NO_WARNINGS', None))
             macros.append(('_CRT_NONSTDC_NO_WARNINGS', None))
@@ -318,7 +320,7 @@ class CCompiler(object):
         args = []
         libsearch = []
 
-        # When we are using Visual C++...
+        # When we are using Visual C++ or clang-cl...
         if self.check_is_msvc():
             # The search path of the .lib's on Visual C++
             # is dependent on the LIB environmental variable,
@@ -336,7 +338,7 @@ class CCompiler(object):
             args.append('dumpbin.exe')
             args.append('-symbols')
 
-        # When we are not using Visual C++ (i.e. we are using GCC)...
+        # When we are not using Visual C++ nor clang-cl (i.e. we are using GCC)...
         else:
             libtool = utils.get_libtool_command(options)
             if libtool:
diff --git a/giscanner/msvccompiler.py b/giscanner/msvccompiler.py
index d13eb808..0a543982 100644
--- a/giscanner/msvccompiler.py
+++ b/giscanner/msvccompiler.py
@@ -36,6 +36,7 @@ def get_msvc_compiler():
 class MSVCCompiler(distutils.msvccompiler.MSVCCompiler):
 
     def __init__(self, verbose=0, dry_run=0, force=0):
+        super(distutils.msvccompiler.MSVCCompiler, self).__init__()
         CCompiler.__init__(self, verbose, dry_run, force)
         self.__paths = []
         self.__arch = None  # deprecated name
@@ -44,6 +45,16 @@ class MSVCCompiler(distutils.msvccompiler.MSVCCompiler):
                 self.__version = distutils.msvc9compiler.VERSION
         self.initialized = False
         self.preprocess_options = None
+        if self.check_is_clang_cl():
+            cc_cmd = os.environ.get('CC').split()
+            self.cc = cc_cmd[0]
+            self.linker = 'lld-link'
+            self.compile_options = []
+            # Add any arguments added to clang-cl to self.compile_options
+            # such as cross-compilation flags
+            if len(cc_cmd) > 1:
+                self.compile_options.extend(cc_cmd[1:])
+            self.initialized = True
 
     def preprocess(self,
                    source,
@@ -98,3 +109,14 @@ class MSVCCompiler(distutils.msvccompiler.MSVCCompiler):
             return filename[filename.rfind('\\') + 1:]
         else:
             return filename[filename.rfind('\\') + 1:filename.rfind('.')]
+
+    def check_is_clang_cl(self):
+        # To run g-ir-scanner under Windows using clang-cl, set both `CC` and
+        # `CXX` to `clang-cl [<arch_args>]` and ensure that clang-cl.exe and
+        # lld-link.exe are in the PATH in a Visual Studio command prompt.  Note
+        # that the Windows SDK is still needed in this case.  This is in line
+        # with what is done in Meson
+        return (os.environ.get('CC') is not None and
+                os.environ.get('CXX') is not None and
+                os.environ.get('CC').split()[0] == 'clang-cl' and
+                os.environ.get('CXX').split()[0] == 'clang-cl')