Merge pull request #1654 from dcbaker/c-cpp-link

Add a testcase for linking C and C++ static archives into a shared li…

mesonbuild/build.py

@@ -868,6 +868,28 @@ You probably should put it in link_with instead.''')
     def get_aliases(self):
         return {}
 
+    def get_langs_used_by_deps(self):
+        '''
+        Sometimes you want to link to a C++ library that exports C API, which
+        means the linker must link in the C++ stdlib, and we must use a C++
+        compiler for linking. The same is also applicable for objc/objc++, etc,
+        so we can keep using clike_langs for the priority order.
+
+        See: https://github.com/mesonbuild/meson/issues/1653
+        '''
+        langs = []
+        # Check if any of the external libraries were written in this language
+        for dep in self.external_deps:
+            if dep.language not in langs:
+                langs.append(dep.language)
+        # Check if any of the internal libraries this target links to were
+        # written in this language
+        for link_target in self.link_targets:
+            for language in link_target.compilers:
+                if language not in langs:
+                    langs.append(language)
+        return langs
+
     def get_clike_dynamic_linker(self):
         '''
         We use the order of languages in `clike_langs` to determine which
@@ -878,9 +900,20 @@ You probably should put it in link_with instead.''')
         that can link compiled C. We don't actually need to add an exception
         for Vala here because of that.
         '''
+        # Populate list of all compilers, not just those being used to compile
+        # sources in this target
+        if self.is_cross:
+            all_compilers = self.environment.coredata.cross_compilers
+        else:
+            all_compilers = self.environment.coredata.compilers
+        # Languages used by dependencies
+        dep_langs = self.get_langs_used_by_deps()
+        # Pick a compiler based on the language priority-order
         for l in clike_langs:
-            if l in self.compilers:
+            if l in self.compilers or l in dep_langs:
-                return self.compilers[l]
+                return all_compilers[l]
+        m = 'Could not get a dynamic linker for build target {!r}'
+        raise AssertionError(m.format(self.name))
 
     def get_using_msvc(self):
         '''

mesonbuild/dependencies.py

@@ -51,6 +51,7 @@ class DependencyMethods(Enum):
 class Dependency:
     def __init__(self, type_name, kwargs):
         self.name = "null"
+        self.language = None
         self.is_found = False
         self.type_name = type_name
         method = DependencyMethods(kwargs.get('method', 'auto'))
@@ -570,11 +571,12 @@ class ExternalProgram:
         return self.name
 
 class ExternalLibrary(Dependency):
-    # TODO: Add `lang` to the parent Dependency object so that dependencies can
+    # TODO: Add `language` support to all Dependency objects so that languages
-    # be expressed for languages other than C-like
+    # can be exposed for dependencies that support that (i.e., not pkg-config)
-    def __init__(self, name, link_args=None, language=None, silent=False):
+    def __init__(self, name, link_args, language, silent=False):
         super().__init__('external', {})
         self.name = name
+        self.language = language
         self.is_found = False
         self.link_args = []
         self.lang_args = []
@@ -582,9 +584,13 @@ class ExternalLibrary(Dependency):
             self.is_found = True
             if not isinstance(link_args, list):
                 link_args = [link_args]
-            if language:
             self.lang_args = {language: link_args}
-            else:
+            # We special-case Vala for now till the Dependency object gets
+            # proper support for exposing the language it was written in.
+            # Without this, vala-specific link args will end up in the C link
+            # args list if you link to a Vala library.
+            # This hack use to be in CompilerHolder.find_library().
+            if language != 'vala':
                 self.link_args = link_args
         if not silent:
             if self.is_found:

mesonbuild/interpreter.py

@@ -982,14 +982,7 @@ class CompilerHolder(InterpreterObject):
         if required and not linkargs:
             l = self.compiler.language.capitalize()
             raise InterpreterException('{} library {!r} not found'.format(l, libname))
-        # If this is set to None, the library and link arguments are for
+        lib = dependencies.ExternalLibrary(libname, linkargs, self.compiler.language)
-        # a C-like compiler. Otherwise, it's for some other language that has
-        # a find_library implementation. We do this because it's easier than
-        # maintaining a list of languages that can consume C libraries.
-        lang = None
-        if self.compiler.language == 'vala':
-            lang = 'vala'
-        lib = dependencies.ExternalLibrary(libname, linkargs, language=lang)
         return ExternalLibraryHolder(lib)
 
     def has_argument_method(self, args, kwargs):
@@ -2320,9 +2313,11 @@ class Interpreter(InterpreterBase):
                 raise InterpreterException('Input must be a string or a file')
             if isinstance(inputfile, str):
                 inputfile = os.path.join(self.subdir, inputfile)
+                ifile_abs = os.path.join(self.environment.source_dir, inputfile)
             else:
+                ifile_abs = inputfile.absolute_path(self.environment.source_dir,
+                                                    self.environment.build_dir)
                 inputfile = inputfile.relative_name()
-            ifile_abs = os.path.join(self.environment.source_dir, inputfile)
         elif 'command' in kwargs and '@INPUT@' in kwargs['command']:
             raise InterpreterException('@INPUT@ used as command argument, but no input file specified.')
         # Validate output

test cases/common/146 C and CPP link/foo.c

@@ -0,0 +1,19 @@
+/* Copyright © 2017 Dylan Baker
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "foo.h"
+
+int forty_two(void) {
+    return 42;
+}

test cases/common/146 C and CPP link/foo.cpp

@@ -0,0 +1,31 @@
+/* Copyright © 2017 Dylan Baker
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <vector>
+
+const int cnums[] = {0, 61};
+
+template<typename T, int N>
+std::vector<T> makeVector(const T (&data)[N])
+{
+    return std::vector<T>(data, data+N);
+}
+
+namespace {
+    std::vector<int> numbers = makeVector(cnums);
+}
+
+extern "C" int six_one(void) {
+    return numbers[1];
+}

test cases/common/146 C and CPP link/foo.h

@@ -0,0 +1,16 @@
+/* Copyright © 2017 Dylan Baker
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+int forty_two(void);

test cases/common/146 C and CPP link/foo.hpp

@@ -0,0 +1,24 @@
+/* Copyright © 2017 Dylan Baker
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int six_one(void);
+
+#ifdef __cplusplus
+}
+#endif

test cases/common/146 C and CPP link/foobar.c

@@ -0,0 +1,23 @@
+/* Copyright © 2017 Dylan Baker
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "foo.h"
+#include "foo.hpp"
+#include "foobar.h"
+
+void mynumbers(int nums[]) {
+    nums[0] = forty_two();
+    nums[1] = six_one();
+}

test cases/common/146 C and CPP link/foobar.h

@@ -0,0 +1,16 @@
+/* Copyright © 2017 Dylan Baker
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+void mynumbers(int nums[]);

test cases/common/146 C and CPP link/meson.build

@@ -0,0 +1,58 @@
+# Copyright © 2017 Dylan Baker
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+project('C and C++ static link test', ['c', 'cpp'])
+
+libc = static_library('cfoo', ['foo.c', 'foo.h'])
+
+# Test that linking C libs to external static C++ libs uses the C++ linker
+# Since we can't depend on the test system to provide this, we create one
+# ourselves at configure time and then 'find' it with cxx.find_library().
+cxx = meson.get_compiler('cpp')
+
+if cxx.get_id() == 'msvc'
+  compile_cmd = ['/c', '@INPUT@', '/Fo@OUTPUT@']
+  stlib_cmd = ['lib', '/OUT:@OUTPUT@', '@INPUT@']
+else
+  compile_cmd = ['-c', '-fPIC', '@INPUT@', '-o', '@OUTPUT@']
+  stlib_cmd = ['ar', 'csr', '@OUTPUT@', '@INPUT@']
+endif
+
+foo_cpp_o = configure_file(
+  input : 'foo.cpp',
+  output : 'foo.cpp.o',
+  command : cxx.cmd_array() + compile_cmd)
+
+configure_file(
+  input : foo_cpp_o,
+  output : 'libstcppext.a',
+  command : stlib_cmd)
+
+libstcppext = cxx.find_library('stcppext', dirs : meson.current_build_dir())
+
+libfooext = shared_library(
+  'fooext',
+  ['foobar.c', 'foobar.h'],
+  link_with : libc,
+  dependencies : libstcppext,
+)
+
+# Test that linking C libs to internal static C++ libs uses the C++ linker
+libcpp = static_library('cppfoo', ['foo.cpp', 'foo.hpp'])
+
+libfoo = shared_library(
+  'foo',
+  ['foobar.c', 'foobar.h'],
+  link_with : [libc, libcpp],
+)