Feature/clang (#9477)

* wip

* improving test conf

* fixing some tests

* wip

* wip

* docs

* wip

* wip

* wip

* wip

* fixing test

* remove unused markers

* enable meson

* removing meson version check

* test to see if we break something

* fix visual_studio tests

* wip

* wip

conan/tools/cmake/toolchain.py

@@ -515,6 +515,12 @@ def _get_toolset(self, generator):
                     return "version=14.{}".format(minor)
                 else:
                     return "v14{}".format(minor)
+        elif compiler == "clang":
+            if generator and "Visual" in generator:
+                if "Visual Studio 16" in generator:
+                    return "ClangCL"
+                else:
+                    raise ConanException("CMakeToolchain compiler=clang only supported VS 16")
         return None
 
     def _get_generator_platform(self, generator):

conans/test/conftest.py

@@ -34,8 +34,11 @@
 
 
 tools_locations = {
+    "clang": {"disabled": True},
     'visual_studio': {"default": "15",
-                      "15": {}},
+                      "15": {},
+                      "16": {"disabled": True}},
+
     'pkg_config': {"exe": "pkg-config",
                    "default": "system",
                    # pacman -S pkg-config inside msys2-mingw64
@@ -147,6 +150,7 @@ def _get_tool(name, version):
         version = version or tool.get("default")
         tool_version = tool.get(version)
         if tool_version is not None:
+            assert isinstance(tool_version, dict)
             if tool_version.get("disabled"):
                 _cached_tools[name][version] = False
                 return False

conans/test/functional/toolchains/cmake/test_cmake_toolchain_win_clang.py

@@ -0,0 +1,102 @@
+import platform
+import textwrap
+
+import pytest
+
+from conans.test.assets.cmake import gen_cmakelists
+from conans.test.assets.sources import gen_function_cpp
+from conans.test.utils.tools import TestClient
+from conans.util.files import save
+
+
+@pytest.fixture
+def client():
+    c = TestClient()
+    save(c.cache.new_config_path, "tools.env.virtualenv:auto_use=True")
+    clang_profile = textwrap.dedent("""
+        [settings]
+        os=Windows
+        arch=x86_64
+        build_type=Release
+        compiler=clang
+        compiler.version=12
+
+        [buildenv]
+        CC=clang
+        CXX=clang++
+        RC=clang
+        """)
+    conanfile = textwrap.dedent("""
+        import os
+        from conans import ConanFile
+        from conan.tools.cmake import CMake
+        from conan.tools.layout import cmake_layout
+        class Pkg(ConanFile):
+            settings = "os", "compiler", "build_type", "arch"
+            exports_sources = "*"
+            generators = "CMakeToolchain"
+
+            def layout(self):
+                cmake_layout(self)
+
+            def build(self):
+                cmake = CMake(self)
+                cmake.configure()
+                cmake.build()
+                cmd = os.path.join(self.cpp.build.bindirs[0], "my_app")
+                self.run(cmd, env=["conanrunenv"])
+        """)
+    c.save({"conanfile.py": conanfile,
+            "clang": clang_profile,
+            "src/CMakeLists.txt": gen_cmakelists(appname="my_app", appsources=["main.cpp"]),
+            "src/main.cpp": gen_function_cpp(name="main")})
+    return c
+
+
+@pytest.mark.tool_cmake
+@pytest.mark.tool_mingw64
+@pytest.mark.tool_clang(version="12")
+@pytest.mark.skipif(platform.system() != "Windows", reason="requires Win")
+def test_clang(client):
+    client.run("create . pkg/0.1@ -pr=clang")
+    # clang compilations in Windows will use MinGW Makefiles by default
+    assert 'cmake -G "MinGW Makefiles"' in client.out
+    assert "main __clang_major__12" in client.out
+    # Check this! Clang compiler in Windows is reporting MSC_VER and MSVC_LANG!
+    assert "main _MSC_VER19" in client.out
+    assert "main _MSVC_LANG2014" in client.out
+
+
+@pytest.mark.tool_cmake
+@pytest.mark.tool_clang(version="12")
+@pytest.mark.skipif(platform.system() != "Windows", reason="requires Win")
+def test_clang_cmake_ninja(client):
+    client.run("create . pkg/0.1@ -pr=clang -c tools.cmake.cmaketoolchain:generator=Ninja")
+    assert 'cmake -G "Ninja"' in client.out
+    assert "main __clang_major__12" in client.out
+    # Check this! Clang compiler in Windows is reporting MSC_VER and MSVC_LANG!
+    assert "main _MSC_VER19" in client.out
+    assert "main _MSVC_LANG2014" in client.out
+
+
+@pytest.mark.tool_cmake
+@pytest.mark.tool_visual_studio(version="16")  # With Clang distributed in VS!
+@pytest.mark.skipif(platform.system() != "Windows", reason="requires Win")
+def test_clang_cmake_visual(client):
+    clang_profile = textwrap.dedent("""
+        [settings]
+        os=Windows
+        arch=x86_64
+        build_type=Release
+        compiler=clang
+        compiler.version=11
+        """)
+    # TODO: Clang version is unused, it can change, still 11 from inside VS is used
+    client.save({"clang": clang_profile})
+    client.run("create . pkg/0.1@ -pr=clang "
+               '-c tools.cmake.cmaketoolchain:generator="Visual Studio 16"')
+    assert 'cmake -G "Visual Studio 16"' in client.out
+    assert "main __clang_major__11" in client.out
+    # Check this! Clang compiler in Windows is reporting MSC_VER and MSVC_LANG!
+    assert "main _MSC_VER19" in client.out
+    assert "main _MSVC_LANG2014" in client.out