(__builtin_constant_p) [__GNUC__ <= 2]: Define to 1.

(verify_type__) [verify_error_if_non_const__]: New member/test,
to help detect when verify or verify_expr is mistakenly passed
a non-constant argument within a function.

1 files changed, 11 insertions, 1 deletions

diff --git a/lib/verify.h b/lib/verify.h
index 4461f4e47..099d27061 100644
--- a/lib/verify.h
+++ b/lib/verify.h
@@ -24,13 +24,23 @@
 # define GL_CONCAT0(x, y) x##y
 # define GL_CONCAT(x, y) GL_CONCAT0 (x, y)
 
+/* If gcc predates 3.0, then disable the check below to ensure
+   that verify_type__'s argument is a constant expression.  */
+# if __GNUC__ <= 2
+#  defined __builtin_constant_p(R) 1
+# endif
+
 /* A type that is valid if and only if R is nonzero.
    R should be an integer constant expression.
    verify_type__ and verify_error_if_negative_size__ are symbols that
    are private to this header file.  */
 
 # define verify_type__(R) \
-    struct { int verify_error_if_negative_size__[(R) ? 1 : -1]; }
+    struct { \
+      /* Provoke a compile-time failure if R is a non-constant expression. */ \
+      int verify_error_if_non_const__[__builtin_constant_p (R) ? 1 : -1]; \
+      /* Provoke a compile-time failure if R is nonzero.  */ \
+      int verify_error_if_negative_size__[(R) ? 1 : -1]; }
 
 /* Verify requirement R at compile-time, as a declaration.
    R should be an integer constant expression.