Headers: Add support for ISO9899:2011 rsize_t.

llvm-svn: 179427

Author: ddunbar

clang/lib/Headers/stddef.h

@@ -42,6 +42,17 @@ typedef __PTRDIFF_TYPE__ ptrdiff_t;
 typedef __SIZE_TYPE__ size_t;
 #endif
 
+/* ISO9899:2011 7.20 (C11 Annex K): Define risze_t if __STDC_WANT_LIB_EXT1__ is
+ * enabled. */
+#if (defined(__STDC_WANT_LIB_EXT1__) && __STDC_WANT_LIB_EXT1__ >= 1 && \
+ !defined(_RSIZE_T)) || __has_feature(modules)
+/* Always define rsize_t when modules are available. */
+#if !__has_feature(modules)
+#define _RSIZE_T
+#endif
+typedef __SIZE_TYPE__ rsize_t;
+#endif
+
 #ifndef __cplusplus
 /* Always define wchar_t when modules are available. */
 #if !defined(_WCHAR_T) || __has_feature(modules)

clang/lib/Headers/stdint.h

@@ -667,6 +667,12 @@ typedef __UINTMAX_TYPE__ uintmax_t;
 #define PTRDIFF_MAX __INTN_MAX(__PTRDIFF_WIDTH__)
 #define SIZE_MAX __UINTN_MAX(__SIZE_WIDTH__)
 
+/* ISO9899:2011 7.20 (C11 Annex K): Define RSIZE_MAX if __STDC_WANT_LIB_EXT1__
+ * is enabled. */
+#if defined(__STDC_WANT_LIB_EXT1__) && __STDC_WANT_LIB_EXT1__ >= 1
+#define RSIZE_MAX (SIZE_MAX >> 1)
+#endif
+
 /* C99 7.18.2.5 Limits of greatest-width integer types. */
 #define INTMAX_MIN __INTN_MIN(__INTMAX_WIDTH__)
 #define INTMAX_MAX __INTN_MAX(__INTMAX_WIDTH__)

clang/test/Headers/c11.c

@@ -17,3 +17,8 @@ _Static_assert(__alignas_is_defined, "");
 _Static_assert(__alignof_is_defined, "");
 alignas(alignof(int)) char c[4];
 _Static_assert(__alignof(c) == 4, "");
+
+#define __STDC_WANT_LIB_EXT1__ 1
+#include <stddef.h>
+#include <stdint.h>
+rsize_t x = RSIZE_MAX;