reduce copy & paste

We see several occurrence of "diagnostic push/pop" so why not
make them macros.  Tested on GCC8 / Clang 6.

Note that ruby.h is intentionally left untouched because we don't
want to introduce new public macros.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64118 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

cont.c

@@ -628,9 +628,9 @@ show_vm_pcs(const rb_control_frame_t *cfp,
     }
 }
 #endif
+COMPILER_WARNING_PUSH
 #ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wduplicate-decl-specifier"
+COMPILER_WARNING_IGNORED(-Wduplicate-decl-specifier)
 #endif
 static VALUE
 cont_capture(volatile int *volatile stat)
@@ -694,9 +694,7 @@ cont_capture(volatile int *volatile stat)
 	return contval;
     }
 }
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif
+COMPILER_WARNING_POP
 
 static inline void
 fiber_restore_thread(rb_thread_t *th, rb_fiber_t *fib)

dln.c

@@ -1244,24 +1244,17 @@ rb_w32_check_imported(HMODULE ext, HMODULE mine)
 #endif
 
 #ifdef USE_DLN_DLOPEN
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wpedantic"
-#elif defined(__GNUC__) && (__GNUC__ >= 5)
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wpedantic"
+COMPILER_WARNING_PUSH
+#if defined(__clang__) || GCC_VERSION_SINCE(4, 2, 0)
+COMPILER_WARNING_IGNORED(-Wpedantic)
 #endif
 static bool
 dln_incompatible_library_p(void *handle)
 {
     void *ex = dlsym(handle, EXTERNAL_PREFIX"ruby_xmalloc");
     return ex && ex != ruby_xmalloc;
 }
-#ifdef __clang__
-#pragma clang diagnostic pop
-#elif defined(__GNUC__) && (__GNUC__ >= 5)
-#pragma GCC diagnostic pop
-#endif
+COMPILER_WARNING_POP
 #endif
 
 void*

eval_intern.h

@@ -160,10 +160,10 @@ LONG WINAPI rb_w32_stack_overflow_handler(struct _EXCEPTION_POINTERS *);
 #if defined(USE_UNALIGNED_MEMBER_ACCESS) && USE_UNALIGNED_MEMBER_ACCESS && \
     defined(__clang__)
 # define UNALIGNED_MEMBER_ACCESS(expr) __extension__({ \
-    _Pragma("GCC diagnostic push"); \
-    _Pragma("GCC diagnostic ignored \"-Waddress-of-packed-member\""); \
+    COMPILER_WARNING_PUSH; \
+    COMPILER_WARNING_IGNORED(-Waddress-of-packed-member); \
     typeof(expr) unaligned_member_access_result = (expr); \
-    _Pragma("GCC diagnostic pop"); \
+    COMPILER_WARNING_POP; \
     unaligned_member_access_result; \
 })
 #else

internal.h

@@ -2147,6 +2147,43 @@ rb_obj_builtin_type(VALUE obj)
 # define BITFIELD(type) unsigned int
 #endif
 
+#if defined(_MSC_VER)
+# define COMPILER_WARNING_PUSH          __pragma(warning(push))
+# define COMPILER_WARNING_POP           __pragma(warning(pop))
+# define COMPILER_WARNING_ERROR(flag)   __pragma(warning(error: flag)))
+# define COMPILER_WARNING_IGNORED(flag) __pragma(warning(suppress: flag)))
+
+#elif defined(__clang__) /* clang 2.6 already had this feature */
+# define COMPILER_WARNING_PUSH          _Pragma("clang diagnostic push")
+# define COMPILER_WARNING_POP           _Pragma("clang diagnostic pop")
+# define COMPILER_WARNING_SPECIFIER(kind, msg) \
+    clang diagnostic kind # msg
+# define COMPILER_WARNING_ERROR(flag) \
+    COMPILER_WARNING_PRAGMA(COMPILER_WARNING_SPECIFIER(error, flag))
+# define COMPILER_WARNING_IGNORED(flag) \
+    COMPILER_WARNING_PRAGMA(COMPILER_WARNING_SPECIFIER(ignored, flag))
+
+#elif GCC_VERSION_SINCE(4, 2, 0)
+/* https://gcc.gnu.org/onlinedocs/gcc-4.2.0/gcc/Diagnostic-Pragmas.html */
+# define COMPILER_WARNING_PUSH          _Pragma("GCC diagnostic push")
+# define COMPILER_WARNING_POP           _Pragma("GCC diagnostic pop")
+# define COMPILER_WARNING_SPECIFIER(kind, msg) \
+    GCC diagnostic kind # msg
+# define COMPILER_WARNING_ERROR(flag) \
+    COMPILER_WARNING_PRAGMA(COMPILER_WARNING_SPECIFIER(error, flag))
+# define COMPILER_WARNING_IGNORED(flag) \
+    COMPILER_WARNING_PRAGMA(COMPILER_WARNING_SPECIFIER(ignored, flag))
+
+#else /* other compilers to follow? */
+# define COMPILER_WARNING_PUSH                /* nop */
+# define COMPILER_WARNING_POP                 /* nop */
+# define COMPILER_WARNING_ERROR(cond, flag)   /* nop */
+# define COMPILER_WARNING_ignored(cond, flag) /* nop */
+#endif
+
+#define COMPILER_WARNING_PRAGMA(str) COMPILER_WARNING_PRAGMA_(str)
+#define COMPILER_WARNING_PRAGMA_(str) _Pragma(#str)
+
 #if defined(__cplusplus)
 #if 0
 { /* satisfy cc-mode */

mjit.c

@@ -387,14 +387,13 @@ start_process(const char *path, char *const *argv)
         }
         dev_null = rb_cloexec_open(ruby_null_device, O_WRONLY, 0);
 
+        COMPILER_WARNING_PUSH;
 #ifdef __GNUC__
-# pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+        COMPILER_WARNING_IGNORED(-Wdeprecated-declarations);
 #endif
         if ((pid = vfork()) == 0) {
-#ifdef __GNUC__
-# pragma GCC diagnostic pop
-#endif
+        COMPILER_WARNING_POP;
+
             umask(0077);
             if (mjit_opts.verbose == 0) {
                 /* CC can be started in a thread using a file which has been

process.c

@@ -3972,9 +3972,9 @@ retry_fork_async_signal_safe(int *status, int *ep,
     while (1) {
         prefork();
         disable_child_handler_before_fork(&old);
+        COMPILER_WARNING_PUSH;
 #ifdef __GNUC__
-# pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+        COMPILER_WARNING_IGNORED(-Wdeprecated-declarations);
 #endif
 #ifdef HAVE_WORKING_VFORK
         if (!has_privilege())
@@ -3984,9 +3984,7 @@ retry_fork_async_signal_safe(int *status, int *ep,
 #else
         pid = fork();
 #endif
-#ifdef __GNUC__
-# pragma GCC diagnostic pop
-#endif
+        COMPILER_WARNING_POP;
         if (pid == 0) {/* fork succeed, child process */
             int ret;
             close(ep[0]);
@@ -4055,13 +4053,13 @@ rb_fork_ruby(int *status)
 	prefork();
 	disable_child_handler_before_fork(&old);
 	before_fork_ruby();
+        COMPILER_WARNING_PUSH;
 #ifdef __GNUC__
-# pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+        COMPILER_WARNING_IGNORED(-Wdeprecated-declarations);
 #endif
 	pid = fork();
 #ifdef __GNUC__
-# pragma GCC diagnostic pop
+        COMPILER_WARNING_POP;
 #endif
 	err = errno;
 	after_fork_ruby();

template/prelude.c.tmpl

@@ -138,9 +138,9 @@ prelude_prefix_path(VALUE self)
 % unless preludes.empty?
 #define PRELUDE_NAME(n) rb_usascii_str_new_static(prelude_name##n, sizeof(prelude_name##n)-1)
 #define PRELUDE_CODE(n) rb_usascii_str_new_static(prelude_code##n.L0, sizeof(prelude_code##n))
-#if defined __GNUC__ && __GNUC__ >= 5
-# pragma GCC diagnostic push
-# pragma GCC diagnostic error "-Wmissing-field-initializers"
+COMPILER_WARNING_PUSH
+#if GCC_VERSION_SINCE(4, 2, 0)
+COMPILER_WARNING_ERROR(-Wmissing-field-initializers)
 #endif
 static void
 prelude_eval(VALUE code, VALUE name, int line)
@@ -168,9 +168,7 @@ prelude_eval(VALUE code, VALUE name, int line)
 				      NULL, ISEQ_TYPE_TOP, &optimization));
     rb_ast_dispose(ast);
 }
-#if defined __GNUC__ && __GNUC__ >= 5
-# pragma GCC diagnostic pop
-#endif
+COMPILER_WARNING_POP
 % end
 
 % if @have_sublib