Make [U]INT64CONST safe for use in #if conditions.

tglsfdc · tglsfdc · commit 53863ebeba5f · 2017-09-01T15:14:18.000-04:00
Instead of using a cast to force the constant to be the right width, assume we can plaster on an L, UL, LL, or ULL suffix as appropriate. The old approach to this is very hoary, dating from before we were willing to require compilers to have working int64 types. This fix makes the PG_INT64_MIN, PG_INT64_MAX, and PG_UINT64_MAX constants safe to use in preprocessor conditions, where a cast doesn't work. Other symbolic constants that might be defined using [U]INT64CONST are likewise safer than before. Also fix the SIZE_MAX macro to be similarly safe, if we are forced to provide a definition for that. The test added in commit 2e70d6b happens to do what we want even with the hack "(size_t) -1" definition, but we could easily get burnt on other tests in future. Back-patch to all supported branches, like the previous commits. Discussion: https://postgr.es/m/15883.1504278595@sss.pgh.pa.us
diff --git a/configure b/configure
@@ -13485,31 +13485,6 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
-
-if test x"$HAVE_LONG_LONG_INT_64" = xyes ; then
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-#define INT64CONST(x)  x##LL
-long long int foo = INT64CONST(0x1234567890123456);
-
-int
-main ()
-{
-
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
-
-$as_echo "#define HAVE_LL_CONSTANTS 1" >>confdefs.h
-
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-fi
-
-
 # If we found "long int" is 64 bits, assume snprintf handles it.  If
 # we found we need to use "long long int", better check.  We cope with
 # snprintfs that use %lld, %qd, or %I64d as the format.  If none of these
diff --git a/configure.in b/configure.in
@@ -1704,19 +1704,6 @@ fi
 AC_DEFINE_UNQUOTED(PG_INT64_TYPE, $pg_int64_type,
   [Define to the name of a signed 64-bit integer type.])
 
-dnl If we need to use "long long int", figure out whether nnnLL notation works.
-
-if test x"$HAVE_LONG_LONG_INT_64" = xyes ; then
-  AC_TRY_COMPILE([
-#define INT64CONST(x)  x##LL
-long long int foo = INT64CONST(0x1234567890123456);
-],
-	[],
-	[AC_DEFINE(HAVE_LL_CONSTANTS, 1, [Define to 1 if constants of type 'long long int' should have the suffix LL.])],
-	[])
-fi
-
-
 # If we found "long int" is 64 bits, assume snprintf handles it.  If
 # we found we need to use "long long int", better check.  We cope with
 # snprintfs that use %lld, %qd, or %I64d as the format.  If none of these
diff --git a/src/include/c.h b/src/include/c.h
@@ -265,6 +265,8 @@ typedef long int int64;
 #ifndef HAVE_UINT64
 typedef unsigned long int uint64;
 #endif
+#define INT64CONST(x)  (x##L)
+#define UINT64CONST(x) (x##UL)
 #elif defined(HAVE_LONG_LONG_INT_64)
 /* We have working support for "long long int", use that */
 
@@ -274,23 +276,20 @@ typedef long long int int64;
 #ifndef HAVE_UINT64
 typedef unsigned long long int uint64;
 #endif
+#define INT64CONST(x)  (x##LL)
+#define UINT64CONST(x) (x##ULL)
 #else
 /* neither HAVE_LONG_INT_64 nor HAVE_LONG_LONG_INT_64 */
 #error must have a working 64-bit integer datatype
 #endif
 
-/* Decide if we need to decorate 64-bit constants */
-#ifdef HAVE_LL_CONSTANTS
-#define INT64CONST(x)  ((int64) x##LL)
-#define UINT64CONST(x) ((uint64) x##ULL)
-#else
-#define INT64CONST(x)  ((int64) x)
-#define UINT64CONST(x) ((uint64) x)
-#endif
-
 /* Max value of size_t might be missing if we don't have stdint.h */
 #ifndef SIZE_MAX
-#define SIZE_MAX ((size_t) -1)
+#if SIZEOF_SIZE_T == 8
+#define SIZE_MAX UINT64CONST(0xFFFFFFFFFFFFFFFF)
+#else
+#define SIZE_MAX (0xFFFFFFFFU)
+#endif
 #endif
 
 /* Select timestamp representation (float8 or int64) */
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
@@ -311,10 +311,6 @@
 /* Define to 1 if you have the `z' library (-lz). */
 #undef HAVE_LIBZ
 
-/* Define to 1 if constants of type 'long long int' should have the suffix LL.
-   */
-#undef HAVE_LL_CONSTANTS
-
 /* Define to 1 if the system has the type `locale_t'. */
 #undef HAVE_LOCALE_T
 
diff --git a/src/include/pg_config.h.win32 b/src/include/pg_config.h.win32
@@ -220,12 +220,6 @@
 /* Define to 1 if you have the `z' library (-lz). */
 /* #undef HAVE_LIBZ */
 
-/* Define to 1 if constants of type 'long long int' should have the suffix LL.
-   */
-#if (_MSC_VER > 1200)
-#define HAVE_LL_CONSTANTS 1
-#endif
-
 /* Define to 1 if the system has the type `locale_t'. */
 #define HAVE_LOCALE_T 1
 
@@ -234,7 +228,7 @@
 
 /* Define to 1 if `long long int' works and is 64 bits. */
 #if (_MSC_VER > 1200)
-#define HAVE_LONG_LONG_INT_64
+#define HAVE_LONG_LONG_INT_64 1
 #endif
 
 /* Define to 1 if you have the `mbstowcs_l' function. */
