Use a single WS_NORETURN macro

Having to define two macros for marking a function as never returning
seems a bit redundant. Merge the MSVC and GCC-like attributes into a
single WS_NORETURN.

Tested with Clang 3.7.1, GCC 4.4.7 and even GCC 4.1.2 using this small
program (-Wall -Wextra, the first two generate warnings for
uninitialized variables, the last one compiles without warnings):

    #include <stdlib.h>
    __attribute__((noreturn)) void foo() { exit(1); }
    __attribute__((noreturn)) void bar();
    void bar() { exit(1); }
    int main() {
      int j, i;
      if (i) { bar(); return j; }
      foo();
      return j;
    }

Change-Id: I7d19c15e61b8f8fa4936864407199c4109f8cc82
Reviewed-on: https://code.wireshark.org/review/14822
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Guy Harris <guy@alum.mit.edu>
Reviewed-by: Peter Wu <peter@lekensteyn.nl>

8 files changed, 27 insertions, 49 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1722044a7a..8b864fc4ce 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -587,9 +587,14 @@ if( NOT CMAKE_C_COMPILER_ID MATCHES "MSVC")
 endif()
 
 if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_C_COMPILER_ID MATCHES "Clang")
-	set (C_UNUSED "__attribute__((unused))" )
+	set (C_UNUSED	    "__attribute__((unused))" )
+	set (WS_NORETURN    "__attribute__((noreturn))")
+elseif(MSVC)
+	set (C_UNUSED	    "")
+	set (WS_NORETURN    "__declspec(noreturn)")
 else()
-	set (C_UNUSED "" )
+	set (C_UNUSED	    "")
+	set (WS_NORETURN    "")
 endif()
 
 set(WIRESHARK_LD_FLAGS
@@ -1143,14 +1148,10 @@ gmx_test_large_files(GMX_LARGEFILES)
 add_definitions( -DTOP_SRCDIR=\"${CMAKE_SOURCE_DIR}\" )
 
 if(WIN32)
-	set(WS_MSVC_NORETURN "__declspec(noreturn)")
-
 	# Disable deprecation
 	if(MSVC80 OR MSVC90)
 		add_definitions(-D_CRT_SECURE_NO_DEPRECATE -D_CRT_NONSTDC_NO_DEPRECATE)
 	endif()
-else()
-	set(WS_MSVC_NORETURN " ")
 endif()
 
 if (${GIT_EXECUTABLE})
diff --git a/cmakeconfig.h.in b/cmakeconfig.h.in
index 75d9433582..bb62fb6737 100644
--- a/cmakeconfig.h.in
+++ b/cmakeconfig.h.in
@@ -415,15 +415,6 @@
 #cmakedefine _LARGE_FILES
 #cmakedefine _FILE_OFFSET_BITS @_FILE_OFFSET_BITS@
 
-/* Define WS_MSVC_NORETURN appropriately for declarations of routines that
-   never return (just like Charlie on the MTA).
-
-   Note that MSVC++ expects __declspec(noreturn) to precede the function
-   name and GCC, as far as I know, expects __attribute__((noreturn)) to
-   follow the function name, so we need two different flavors of
-   noreturn tag.  */
-#define WS_MSVC_NORETURN @WS_MSVC_NORETURN@
-
 /* Define to 1 if `lex' declares `yytext' as a `char *' by default, not a
    `char[]'. */
 /* Note: not use in the code */
@@ -433,6 +424,9 @@
    However, we do need it for some headers that are shared between C and C++. */
 #define _U_ ${C_UNUSED}
 
+/* Hint to the compiler that a function never returns */
+#define WS_NORETURN @WS_NORETURN@
+
 #if defined(_WIN32)
 
    /* WpdPack/INclude/pcap/pcap.h checks for "#if defined(WIN32)" */
diff --git a/config.h.win32 b/config.h.win32
index f1be3dfaa4..3273f7b8ed 100644
--- a/config.h.win32
+++ b/config.h.win32
@@ -79,17 +79,6 @@
 @PCAP_NG_DEFAULT@
 @WANT_PACKET_EDITOR@
 
-/*
- * Define WS_MSVC_NORETURN appropriately for declarations of routines that
- * never return (just like Charlie on the MTA).
- *
- * Note that MSVC++ expects __declspec(noreturn) to precede the function
- * name and GCC, as far as I know, expects __attribute__((noreturn)) to
- * follow the function name, so we need two different flavors of
- * noreturn tag.
- */
-#define WS_MSVC_NORETURN	__declspec(noreturn)
-
 /* Define if you have the floorl function. */
 #define HAVE_FLOORL 1
 
@@ -212,6 +201,9 @@
  */
 #define _U_
 
+/* Hint to the compiler that a function never returns */
+#define WS_NORETURN	__declspec(noreturn)
+
 /* Visual C 9 (2008), Visual C 10 (2010) and Visual C 11 (2012) and Visual C 12 (2013) need these prototypes */
 #if _MSC_VER >= 1500
 #define NTDDI_VERSION NTDDI_WINXPSP3
diff --git a/configure.ac b/configure.ac
index 272af90a7b..50f6c85ff8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1221,8 +1221,10 @@ AC_SUBST(CFLAGS_SSE42)
 #
 if test "x$GCC" = "xyes" -o "x$CC" = "xclang" ; then
   AC_DEFINE(_U_, __attribute__((unused)), [Hint to the compiler that a function parameters is not used])
+  AC_DEFINE(WS_NORETURN, __attribute((noreturn)), [Hint to the compiler that a function never returns])
 else
   AC_DEFINE(_U_, , [Hint to the compiler that a function parameters is not used])
+  AC_DEFINE(WS_NORETURN, , [Hint to the compiler that a function never returns])
 fi
 
 # If we're running GCC or CLang, use FORTIFY_SOURCE=2
@@ -2651,17 +2653,6 @@ else
 fi
 AC_SUBST(LIBSSH_LIBS)
 
-#
-# Define WS_MSVC_NORETURN appropriately for declarations of routines that
-# never return (just like Charlie on the MTA).
-#
-# Note that MSVC++ expects __declspec(noreturn) to precede the function
-# name and GCC, as far as I know, expects __attribute__((noreturn)) to
-# follow the function name, so we need two different flavors of
-# noreturn tag.
-#
-AC_DEFINE(WS_MSVC_NORETURN,, [Define as the string to precede declarations of routines that never return])
-
 dnl Checks for typedefs, structures, and compiler characteristics.
 # AC_C_CONST
 
diff --git a/dumpcap.c b/dumpcap.c
index c99ee45a42..a44d4f0d36 100644
--- a/dumpcap.c
+++ b/dumpcap.c
@@ -394,7 +394,7 @@ static void capture_loop_queue_packet_cb(u_char *pcap_opts_p, const struct pcap_
 static void capture_loop_get_errmsg(char *errmsg, int errmsglen, const char *fname,
                                     int err, gboolean is_close);
 
-static void WS_MSVC_NORETURN exit_main(int err) G_GNUC_NORETURN;
+static void WS_NORETURN exit_main(int err);
 
 static void report_new_capture_file(const char *filename);
 static void report_packet_count(unsigned int packet_count);
diff --git a/epan/except.c b/epan/except.c
index de6021c362..881796ebd8 100644
--- a/epan/except.c
+++ b/epan/except.c
@@ -180,7 +180,7 @@ static int match(const volatile except_id_t *thrown, const except_id_t *caught)
     return group_match && code_match;
 }
 
-G_GNUC_NORETURN WS_MSVC_NORETURN static void do_throw(except_t *except)
+WS_NORETURN static void do_throw(except_t *except)
 {
     struct except_stacknode *top;
 
@@ -261,7 +261,7 @@ struct except_stacknode *except_pop(void)
     return top;
 }
 
-G_GNUC_NORETURN WS_MSVC_NORETURN void except_rethrow(except_t *except)
+WS_NORETURN void except_rethrow(except_t *except)
 {
     struct except_stacknode *top = get_top();
     assert (top != 0);
@@ -271,7 +271,7 @@ G_GNUC_NORETURN WS_MSVC_NORETURN void except_rethrow(except_t *except)
     do_throw(except);
 }
 
-G_GNUC_NORETURN WS_MSVC_NORETURN void except_throw(long group, long code, const char *msg)
+WS_NORETURN void except_throw(long group, long code, const char *msg)
 {
     except_t except;
 
@@ -289,7 +289,7 @@ G_GNUC_NORETURN WS_MSVC_NORETURN void except_throw(long group, long code, const
     do_throw(&except);
 }
 
-G_GNUC_NORETURN WS_MSVC_NORETURN void except_throwd(long group, long code, const char *msg, void *data)
+WS_NORETURN void except_throwd(long group, long code, const char *msg, void *data)
 {
     except_t except;
 
@@ -306,7 +306,7 @@ G_GNUC_NORETURN WS_MSVC_NORETURN void except_throwd(long group, long code, const
  * XCEPT_BUFFER_SIZE?  We could then just use this to generate formatted
  * messages.
  */
-G_GNUC_NORETURN WS_MSVC_NORETURN void except_throwf(long group, long code, const char *fmt, ...)
+WS_NORETURN void except_throwf(long group, long code, const char *fmt, ...)
 {
     char *buf = (char *)except_alloc(XCEPT_BUFFER_SIZE);
     va_list vl;
diff --git a/epan/except.h b/epan/except.h
index 063218274a..0f979637e9 100644
--- a/epan/except.h
+++ b/epan/except.h
@@ -92,11 +92,11 @@ WS_DLL_PUBLIC struct except_stacknode *except_pop(void);
 /* public interface functions */
 WS_DLL_PUBLIC int except_init(void);
 WS_DLL_PUBLIC void except_deinit(void);
-WS_DLL_PUBLIC WS_MSVC_NORETURN void except_rethrow(except_t *) G_GNUC_NORETURN;
-WS_DLL_PUBLIC WS_MSVC_NORETURN void except_throw(long, long, const char *) G_GNUC_NORETURN;
-WS_DLL_PUBLIC WS_MSVC_NORETURN void except_throwd(long, long, const char *, void *) G_GNUC_NORETURN;
-WS_DLL_PUBLIC WS_MSVC_NORETURN void except_throwf(long, long, const char *, ...)
-    G_GNUC_NORETURN G_GNUC_PRINTF(3, 4);
+WS_DLL_PUBLIC WS_NORETURN void except_rethrow(except_t *);
+WS_DLL_PUBLIC WS_NORETURN void except_throw(long, long, const char *);
+WS_DLL_PUBLIC WS_NORETURN void except_throwd(long, long, const char *, void *);
+WS_DLL_PUBLIC WS_NORETURN void except_throwf(long, long, const char *, ...)
+    G_GNUC_PRINTF(3, 4);
 WS_DLL_PUBLIC void (*except_unhandled_catcher(void (*)(except_t *)))(except_t *);
 extern unsigned long except_code(except_t *);
 extern unsigned long except_group(except_t *);
diff --git a/epan/proto.h b/epan/proto.h
index 7d6ce083c2..9119038dcf 100644
--- a/epan/proto.h
+++ b/epan/proto.h
@@ -120,7 +120,7 @@ typedef struct _protocol protocol_t;
  *
  * @param message string to use as the message
  */
-WS_DLL_PUBLIC WS_MSVC_NORETURN void proto_report_dissector_bug(const char *message) G_GNUC_NORETURN;
+WS_DLL_PUBLIC WS_NORETURN void proto_report_dissector_bug(const char *message);
 
 #define REPORT_DISSECTOR_BUG(message)  \
 	proto_report_dissector_bug(message)