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Diffstat (limited to 'lib/gllib/verify.h')
| -rw-r--r-- | lib/gllib/verify.h | 279 |
1 files changed, 0 insertions, 279 deletions
diff --git a/lib/gllib/verify.h b/lib/gllib/verify.h deleted file mode 100644 index a9ef798..0000000 --- a/lib/gllib/verify.h +++ /dev/null @@ -1,279 +0,0 @@ -/* Compile-time assert-like macros. - - Copyright (C) 2005-2006, 2009-2017 Free Software Foundation, Inc. - - This program is free software: you can redistribute it and/or modify - it under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with this program. If not, see <http://www.gnu.org/licenses/>. */ - -/* Written by Paul Eggert, Bruno Haible, and Jim Meyering. */ - -#ifndef _GL_VERIFY_H -#define _GL_VERIFY_H - - -/* Define _GL_HAVE__STATIC_ASSERT to 1 if _Static_assert works as per C11. - This is supported by GCC 4.6.0 and later, in C mode, and its use - here generates easier-to-read diagnostics when verify (R) fails. - - Define _GL_HAVE_STATIC_ASSERT to 1 if static_assert works as per C++11. - This will likely be supported by future GCC versions, in C++ mode. - - Use this only with GCC. If we were willing to slow 'configure' - down we could also use it with other compilers, but since this - affects only the quality of diagnostics, why bother? */ -#if (4 < __GNUC__ + (6 <= __GNUC_MINOR__) \ - && (201112L <= __STDC_VERSION__ || !defined __STRICT_ANSI__) \ - && !defined __cplusplus) -# define _GL_HAVE__STATIC_ASSERT 1 -#endif -/* The condition (99 < __GNUC__) is temporary, until we know about the - first G++ release that supports static_assert. */ -#if (99 < __GNUC__) && defined __cplusplus -# define _GL_HAVE_STATIC_ASSERT 1 -#endif - -/* FreeBSD 9.1 <sys/cdefs.h>, included by <stddef.h> and lots of other - system headers, defines a conflicting _Static_assert that is no - better than ours; override it. */ -#ifndef _GL_HAVE_STATIC_ASSERT -# include <stddef.h> -# undef _Static_assert -#endif - -/* Each of these macros verifies that its argument R is nonzero. To - be portable, R should be an integer constant expression. Unlike - assert (R), there is no run-time overhead. - - If _Static_assert works, verify (R) uses it directly. Similarly, - _GL_VERIFY_TRUE works by packaging a _Static_assert inside a struct - that is an operand of sizeof. - - The code below uses several ideas for C++ compilers, and for C - compilers that do not support _Static_assert: - - * The first step is ((R) ? 1 : -1). Given an expression R, of - integral or boolean or floating-point type, this yields an - expression of integral type, whose value is later verified to be - constant and nonnegative. - - * Next this expression W is wrapped in a type - struct _gl_verify_type { - unsigned int _gl_verify_error_if_negative: W; - }. - If W is negative, this yields a compile-time error. No compiler can - deal with a bit-field of negative size. - - One might think that an array size check would have the same - effect, that is, that the type struct { unsigned int dummy[W]; } - would work as well. However, inside a function, some compilers - (such as C++ compilers and GNU C) allow local parameters and - variables inside array size expressions. With these compilers, - an array size check would not properly diagnose this misuse of - the verify macro: - - void function (int n) { verify (n < 0); } - - * For the verify macro, the struct _gl_verify_type will need to - somehow be embedded into a declaration. To be portable, this - declaration must declare an object, a constant, a function, or a - typedef name. If the declared entity uses the type directly, - such as in - - struct dummy {...}; - typedef struct {...} dummy; - extern struct {...} *dummy; - extern void dummy (struct {...} *); - extern struct {...} *dummy (void); - - two uses of the verify macro would yield colliding declarations - if the entity names are not disambiguated. A workaround is to - attach the current line number to the entity name: - - #define _GL_CONCAT0(x, y) x##y - #define _GL_CONCAT(x, y) _GL_CONCAT0 (x, y) - extern struct {...} * _GL_CONCAT (dummy, __LINE__); - - But this has the problem that two invocations of verify from - within the same macro would collide, since the __LINE__ value - would be the same for both invocations. (The GCC __COUNTER__ - macro solves this problem, but is not portable.) - - A solution is to use the sizeof operator. It yields a number, - getting rid of the identity of the type. Declarations like - - extern int dummy [sizeof (struct {...})]; - extern void dummy (int [sizeof (struct {...})]); - extern int (*dummy (void)) [sizeof (struct {...})]; - - can be repeated. - - * Should the implementation use a named struct or an unnamed struct? - Which of the following alternatives can be used? - - extern int dummy [sizeof (struct {...})]; - extern int dummy [sizeof (struct _gl_verify_type {...})]; - extern void dummy (int [sizeof (struct {...})]); - extern void dummy (int [sizeof (struct _gl_verify_type {...})]); - extern int (*dummy (void)) [sizeof (struct {...})]; - extern int (*dummy (void)) [sizeof (struct _gl_verify_type {...})]; - - In the second and sixth case, the struct type is exported to the - outer scope; two such declarations therefore collide. GCC warns - about the first, third, and fourth cases. So the only remaining - possibility is the fifth case: - - extern int (*dummy (void)) [sizeof (struct {...})]; - - * GCC warns about duplicate declarations of the dummy function if - -Wredundant-decls is used. GCC 4.3 and later have a builtin - __COUNTER__ macro that can let us generate unique identifiers for - each dummy function, to suppress this warning. - - * This implementation exploits the fact that older versions of GCC, - which do not support _Static_assert, also do not warn about the - last declaration mentioned above. - - * GCC warns if -Wnested-externs is enabled and verify() is used - within a function body; but inside a function, you can always - arrange to use verify_expr() instead. - - * In C++, any struct definition inside sizeof is invalid. - Use a template type to work around the problem. */ - -/* Concatenate two preprocessor tokens. */ -#define _GL_CONCAT(x, y) _GL_CONCAT0 (x, y) -#define _GL_CONCAT0(x, y) x##y - -/* _GL_COUNTER is an integer, preferably one that changes each time we - use it. Use __COUNTER__ if it works, falling back on __LINE__ - otherwise. __LINE__ isn't perfect, but it's better than a - constant. */ -#if defined __COUNTER__ && __COUNTER__ != __COUNTER__ -# define _GL_COUNTER __COUNTER__ -#else -# define _GL_COUNTER __LINE__ -#endif - -/* Generate a symbol with the given prefix, making it unique if - possible. */ -#define _GL_GENSYM(prefix) _GL_CONCAT (prefix, _GL_COUNTER) - -/* Verify requirement R at compile-time, as an integer constant expression - that returns 1. If R is false, fail at compile-time, preferably - with a diagnostic that includes the string-literal DIAGNOSTIC. */ - -#define _GL_VERIFY_TRUE(R, DIAGNOSTIC) \ - (!!sizeof (_GL_VERIFY_TYPE (R, DIAGNOSTIC))) - -#ifdef __cplusplus -# if !GNULIB_defined_struct__gl_verify_type -template <int w> - struct _gl_verify_type { - unsigned int _gl_verify_error_if_negative: w; - }; -# define GNULIB_defined_struct__gl_verify_type 1 -# endif -# define _GL_VERIFY_TYPE(R, DIAGNOSTIC) \ - _gl_verify_type<(R) ? 1 : -1> -#elif defined _GL_HAVE__STATIC_ASSERT -# define _GL_VERIFY_TYPE(R, DIAGNOSTIC) \ - struct { \ - _Static_assert (R, DIAGNOSTIC); \ - int _gl_dummy; \ - } -#else -# define _GL_VERIFY_TYPE(R, DIAGNOSTIC) \ - struct { unsigned int _gl_verify_error_if_negative: (R) ? 1 : -1; } -#endif - -/* Verify requirement R at compile-time, as a declaration without a - trailing ';'. If R is false, fail at compile-time, preferably - with a diagnostic that includes the string-literal DIAGNOSTIC. - - Unfortunately, unlike C11, this implementation must appear as an - ordinary declaration, and cannot appear inside struct { ... }. */ - -#ifdef _GL_HAVE__STATIC_ASSERT -# define _GL_VERIFY _Static_assert -#else -# define _GL_VERIFY(R, DIAGNOSTIC) \ - extern int (*_GL_GENSYM (_gl_verify_function) (void)) \ - [_GL_VERIFY_TRUE (R, DIAGNOSTIC)] -#endif - -/* _GL_STATIC_ASSERT_H is defined if this code is copied into assert.h. */ -#ifdef _GL_STATIC_ASSERT_H -# if !defined _GL_HAVE__STATIC_ASSERT && !defined _Static_assert -# define _Static_assert(R, DIAGNOSTIC) _GL_VERIFY (R, DIAGNOSTIC) -# endif -# if !defined _GL_HAVE_STATIC_ASSERT && !defined static_assert -# define static_assert _Static_assert /* C11 requires this #define. */ -# endif -#endif - -/* @assert.h omit start@ */ - -/* Each of these macros verifies that its argument R is nonzero. To - be portable, R should be an integer constant expression. Unlike - assert (R), there is no run-time overhead. - - There are two macros, since no single macro can be used in all - contexts in C. verify_true (R) is for scalar contexts, including - integer constant expression contexts. verify (R) is for declaration - contexts, e.g., the top level. */ - -/* Verify requirement R at compile-time, as an integer constant expression. - Return 1. This is equivalent to verify_expr (R, 1). - - verify_true is obsolescent; please use verify_expr instead. */ - -#define verify_true(R) _GL_VERIFY_TRUE (R, "verify_true (" #R ")") - -/* Verify requirement R at compile-time. Return the value of the - expression E. */ - -#define verify_expr(R, E) \ - (_GL_VERIFY_TRUE (R, "verify_expr (" #R ", " #E ")") ? (E) : (E)) - -/* Verify requirement R at compile-time, as a declaration without a - trailing ';'. */ - -#define verify(R) _GL_VERIFY (R, "verify (" #R ")") - -#ifndef __has_builtin -# define __has_builtin(x) 0 -#endif - -/* Assume that R always holds. This lets the compiler optimize - accordingly. R should not have side-effects; it may or may not be - evaluated. Behavior is undefined if R is false. */ - -#if (__has_builtin (__builtin_unreachable) \ - || 4 < __GNUC__ + (5 <= __GNUC_MINOR__)) -# define assume(R) ((R) ? (void) 0 : __builtin_unreachable ()) -#elif 1200 <= _MSC_VER -# define assume(R) __assume (R) -#elif ((defined GCC_LINT || defined lint) \ - && (__has_builtin (__builtin_trap) \ - || 3 < __GNUC__ + (3 < __GNUC_MINOR__ + (4 <= __GNUC_PATCHLEVEL__)))) - /* Doing it this way helps various packages when configured with - --enable-gcc-warnings, which compiles with -Dlint. It's nicer - when 'assume' silences warnings even with older GCCs. */ -# define assume(R) ((R) ? (void) 0 : __builtin_trap ()) -#else -# define assume(R) ((void) (0 && (R))) -#endif - -/* @assert.h omit end@ */ - -#endif |