1 files changed, 48 insertions, 10 deletions

diff --git a/mesonbuild/compilers.py b/mesonbuild/compilers.py
index 454cdba..2feae88 100644
--- a/mesonbuild/compilers.py
+++ b/mesonbuild/compilers.py
@@ -513,6 +513,13 @@ class CCompiler(Compiler):
     def get_no_optimization_args(self):
         return ['-O0']
 
+    def get_compiler_check_args(self):
+        '''
+        Get arguments useful for compiler checks such as being permissive in
+        the code quality and not doing any optimization.
+        '''
+        return self.get_no_optimization_args()
+
     def get_output_args(self, target):
         return ['-o', target]
 
@@ -644,9 +651,14 @@ int someSymbolHereJustForFun;
             extra_args = []
         templ = '''{2}
 #include <{0}>
-int main () {{ {1}; }}'''
-        # Pass -O0 to ensure that the symbol isn't optimized away
-        args = extra_args + self.get_no_optimization_args()
+int main () {{
+  /* If it's not defined as a macro, try to use as a symbol */
+  #ifndef {1}
+    {1};
+  #endif
+  return 0;
+}}'''
+        args = extra_args + self.get_compiler_check_args()
         return self.compiles(templ.format(hname, symbol, prefix), env, args, dependencies)
 
     @contextlib.contextmanager
@@ -785,7 +797,7 @@ int main(int argc, char **argv) {{
 %s
 int temparray[%d-sizeof(%s)];
 '''
-        args = extra_args + self.get_no_optimization_args()
+        args = extra_args + self.get_compiler_check_args()
         if not self.compiles(element_exists_templ.format(prefix, element), env, args, dependencies):
             return -1
         for i in range(1, 1024):
@@ -834,7 +846,7 @@ struct tmp {
 
 int testarray[%d-offsetof(struct tmp, target)];
 '''
-        args = extra_args + self.get_no_optimization_args()
+        args = extra_args + self.get_compiler_check_args()
         if not self.compiles(type_exists_templ.format(typename), env, args, dependencies):
             return -1
         for i in range(1, 1024):
@@ -919,7 +931,7 @@ int main(int argc, char **argv) {
         head = '#include <limits.h>\n{0}\n'
         # We don't know what the function takes or returns, so try to use it as
         # a function pointer
-        main = '\nint main() {{ int a = (int) &{1}; }}'
+        main = '\nint main() {{ void *a = (void*) &{1}; }}'
         return head, main
 
     def has_function(self, funcname, prefix, env, extra_args=None, dependencies=None):
@@ -968,9 +980,8 @@ int main(int argc, char **argv) {
             head, main = self._no_prototype_templ()
         templ = head + stubs_fail + main
 
-        # Add -O0 to ensure that the symbol isn't optimized away by the compiler
-        args = extra_args + self.get_no_optimization_args()
-        if self.links(templ.format(prefix, funcname), env, extra_args, dependencies):
+        args = extra_args + self.get_compiler_check_args()
+        if self.links(templ.format(prefix, funcname), env, args, dependencies):
             return True
         # Some functions like alloca() are defined as compiler built-ins which
         # are inlined by the compiler, so test for that instead. Built-ins are
@@ -1049,6 +1060,20 @@ class CPPCompiler(CCompiler):
         code = 'class breakCCompiler;int main(int argc, char **argv) { return 0; }\n'
         return self.sanity_check_impl(work_dir, environment, 'sanitycheckcpp.cc', code)
 
+    def has_header_symbol(self, hname, symbol, prefix, env, extra_args=None, dependencies=None):
+        # Check if it's a C-like symbol
+        if super().has_header_symbol(hname, symbol, prefix, env, extra_args, dependencies):
+            return True
+        # Check if it's a class or a template
+        if extra_args is None:
+            extra_args = []
+        templ = '''{2}
+#include <{0}>
+using {1};
+int main () {{ return 0; }}'''
+        args = extra_args + self.get_compiler_check_args()
+        return self.compiles(templ.format(hname, symbol, prefix), env, args, dependencies)
+
 class ObjCCompiler(CCompiler):
     def __init__(self, exelist, version, is_cross, exe_wrap):
         self.language = 'objc'
@@ -1868,9 +1893,10 @@ class VisualStudioCCompiler(CCompiler):
         pdbarr += ['pdb']
         return ['/DEBUG', '/PDB:' + '.'.join(pdbarr)]
 
-class VisualStudioCPPCompiler(VisualStudioCCompiler):
+class VisualStudioCPPCompiler(VisualStudioCCompiler, CPPCompiler):
     def __init__(self, exelist, version, is_cross, exe_wrap):
         self.language = 'cpp'
+        CPPCompiler.__init__(self, exelist, version, is_cross, exe_wrap)
         VisualStudioCCompiler.__init__(self, exelist, version, is_cross, exe_wrap)
         self.base_options = ['b_pch'] # FIXME add lto, pgo and the like
 
@@ -2045,6 +2071,12 @@ class GnuCPPCompiler(GnuCompiler, CPPCompiler):
             return options['cpp_winlibs'].value
         return []
 
+    def get_compiler_check_args(self):
+        # -fpermissive allows non-conforming code to compile which is necessary
+        # for many C++ checks. Particularly, the has_header_symbol check is
+        # too strict without this and always fails.
+        return self.get_no_optimization_args() + ['-fpermissive']
+
 class GnuObjCCompiler(GnuCompiler,ObjCCompiler):
 
     def __init__(self, exelist, version, is_cross, exe_wrapper=None, defines=None):
@@ -2067,6 +2099,12 @@ class GnuObjCPPCompiler(GnuCompiler, ObjCPPCompiler):
                           '2': ['-Wall', '-Wextra', '-Winvalid-pch', '-Wnon-virtual-dtor'],
                           '3' : ['-Wall', '-Wpedantic', '-Wextra', '-Winvalid-pch', '-Wnon-virtual-dtor']}
 
+    def get_compiler_check_args(self):
+        # -fpermissive allows non-conforming code to compile which is necessary
+        # for many ObjC++ checks. Particularly, the has_header_symbol check is
+        # too strict without this and always fails.
+        return self.get_no_optimization_args() + ['-fpermissive']
+
 class ClangCompiler():
     def __init__(self, clang_type):
         self.id = 'clang'