Merge pull request #3069 from dcbaker/pch_one_arg

Fix targets with C and C++ code that use pre compiled headers

mesonbuild/backend/backends.py

@@ -410,16 +410,10 @@ class Backend:
         args = []
         pchpath = self.get_target_private_dir(target)
         includeargs = compiler.get_include_args(pchpath, False)
-        for lang in ['c', 'cpp']:
-            p = target.get_pch(lang)
-            if not p:
-                continue
-            if compiler.can_compile(p[-1]):
-                header = p[0]
-                args += compiler.get_pch_use_args(pchpath, header)
-        if len(args) > 0:
-            args = includeargs + args
-        return args
+        p = target.get_pch(compiler.get_language())
+        if p:
+            args += compiler.get_pch_use_args(pchpath, p[0])
+        return includeargs + args
 
     @staticmethod
     def escape_extra_args(compiler, args):

test cases/common/15 mixed pch/meson.build

@@ -1,6 +1,19 @@
 project('mixed C and C++ pch test', 'cpp', 'c')
 
 
-exe = executable('prog', 'main.cc', 'func.c',
-c_pch : ['pch/func.h', 'pch/func_pch.c'],
-cpp_pch : ['pch/main_pch.cc', 'pch/main.h'])
+exe = executable(
+  'prog',
+  files('main.cc', 'func.c'),
+  c_pch : ['pch/func.h', 'pch/func_pch.c'],
+  cpp_pch : ['pch/main_pch.cc', 'pch/main.h'],
+)
+
+cc = meson.get_compiler('c')
+if cc.get_id() != 'msvc'
+  exe2 = executable(
+    'prog2',
+    files('main.cc', 'func.c'),
+    c_pch : 'pch/func.h',
+    cpp_pch : 'pch/main.h',
+  )
+endif