Use DIAG_OFF_FLEX/DIAG_ON_FLEX more consistently.

Add warning C4267 (size_t to int conversion) with MSVC to DIAG_OFF_FLEX.

Addd -Wshorten-64-to-32 with Clang and GCC to DIAG_OFF_FLEX.

Don't explicitly use #pragma to turn off warnings; use DIAG_OFF_FLEX for
all of them.

If we use DIAG_OFF_FLEX, use DIAG_ON_FLEX, even if we have no section of
entirely included code at the end.

Change-Id: Ibfd44e8954704e9a8bcb1bd8e54f31d28357fffb
Reviewed-on: https://code.wireshark.org/review/25817
Petri-Dish: Guy Harris <guy@alum.mit.edu>
Tested-by: Petri Dish Buildbot
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 39 insertions, 5 deletions

diff --git a/ws_diag_control.h b/ws_diag_control.h
index 155c143077..e3ee28ed9c 100644
--- a/ws_diag_control.h
+++ b/ws_diag_control.h
@@ -100,15 +100,49 @@ extern "C" {
  * generated by that version of Flex triggers?
  */
 #if defined(_MSC_VER)
+  /*
+   * Suppress:
+   *
+   *   warning C4018: signed/unsigned mismatch
+   *   warning C4267: 'argument' : conversion from 'size_t' to 'int', possible loss of data
+   */
   #define DIAG_OFF_FLEX \
     __pragma(warning(push)) \
-    __pragma(warning(disable:4018))
+    __pragma(warning(disable:4018)) \
+    __pragma(warning(disable:4267))
   #define DIAG_ON_FLEX	__pragma(warning(pop))
 #else
-  #define DIAG_OFF_FLEX \
-    DIAG_OFF(sign-compare)
-  #define DIAG_ON_FLEX \
-    DIAG_ON(sign-compare)
+  /*
+   * Suppress:
+   *
+   *   -Wsigned-compare warnings
+   *   -Wshorten-64-to-32 warnings, if the compiler *has* -Wshorten-64-to-32
+   *
+   * We use DIAG_OFF() and DIAG_ON(), so we only use features that the
+   * compiler supports.
+   *
+   * We disable -Wshorten-64-to-32 if we're using Clang, or if __APPLE__
+   * is defined; that option was originally added to an Apple version of
+   * GCC, and at least some versions of Clang support it - given that
+   * the Clang work started at Apple, it may be in all versions of Clang.
+   *
+   * (Does no version of GCC or Clang support the same generic "you're
+   * narrowing a value, and you didn't throw in a cast to assert that
+   * you know what you're doing" warning that MSVC does?)
+   */
+  #if defined(__clang__) || defined(__APPLE__)
+    #define DIAG_OFF_FLEX \
+      DIAG_OFF(sign-compare) \
+      DIAG_OFF(shorten-64-to-32)
+    #define DIAG_ON_FLEX \
+      DIAG_ON(shorten-64-to-32) \
+      DIAG_ON(sign-compare)
+  #else
+    #define DIAG_OFF_FLEX \
+      DIAG_OFF(sign-compare)
+    #define DIAG_ON_FLEX \
+      DIAG_ON(sign-compare)
+  #endif
 #endif
 
 /*