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Diffstat (limited to 'contrib/ccan/compiler')
| -rw-r--r-- | contrib/ccan/compiler/LICENSE | 28 | ||||
| -rw-r--r-- | contrib/ccan/compiler/_info | 64 | ||||
| -rw-r--r-- | contrib/ccan/compiler/compiler.h | 231 | ||||
| -rw-r--r-- | contrib/ccan/compiler/test/compile_fail-printf.c | 22 | ||||
| -rw-r--r-- | contrib/ccan/compiler/test/run-is_compile_constant.c | 15 |
5 files changed, 360 insertions, 0 deletions
diff --git a/contrib/ccan/compiler/LICENSE b/contrib/ccan/compiler/LICENSE new file mode 100644 index 0000000..feb9b11 --- /dev/null +++ b/contrib/ccan/compiler/LICENSE @@ -0,0 +1,28 @@ +Statement of Purpose + +The laws of most jurisdictions throughout the world automatically confer exclusive Copyright and Related Rights (defined below) upon the creator and subsequent owner(s) (each and all, an "owner") of an original work of authorship and/or a database (each, a "Work"). + +Certain owners wish to permanently relinquish those rights to a Work for the purpose of contributing to a commons of creative, cultural and scientific works ("Commons") that the public can reliably and without fear of later claims of infringement build upon, modify, incorporate in other works, reuse and redistribute as freely as possible in any form whatsoever and for any purposes, including without limitation commercial purposes. These owners may contribute to the Commons to promote the ideal of a free culture and the further production of creative, cultural and scientific works, or to gain reputation or greater distribution for their Work in part through the use and efforts of others. + +For these and/or other purposes and motivations, and without any expectation of additional consideration or compensation, the person associating CC0 with a Work (the "Affirmer"), to the extent that he or she is an owner of Copyright and Related Rights in the Work, voluntarily elects to apply CC0 to the Work and publicly distribute the Work under its terms, with knowledge of his or her Copyright and Related Rights in the Work and the meaning and intended legal effect of CC0 on those rights. + +1. Copyright and Related Rights. A Work made available under CC0 may be protected by copyright and related or neighboring rights ("Copyright and Related Rights"). 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Should any part of the License for any reason be judged legally invalid or ineffective under applicable law, such partial invalidity or ineffectiveness shall not invalidate the remainder of the License, and in such case Affirmer hereby affirms that he or she will not (i) exercise any of his or her remaining Copyright and Related Rights in the Work or (ii) assert any associated claims and causes of action with respect to the Work, in either case contrary to Affirmer's express Statement of Purpose. + +4. Limitations and Disclaimers. + + No trademark or patent rights held by Affirmer are waived, abandoned, surrendered, licensed or otherwise affected by this document. + Affirmer offers the Work as-is and makes no representations or warranties of any kind concerning the Work, express, implied, statutory or otherwise, including without limitation warranties of title, merchantability, fitness for a particular purpose, non infringement, or the absence of latent or other defects, accuracy, or the present or absence of errors, whether or not discoverable, all to the greatest extent permissible under applicable law. + Affirmer disclaims responsibility for clearing rights of other persons that may apply to the Work or any use thereof, including without limitation any person's Copyright and Related Rights in the Work. Further, Affirmer disclaims responsibility for obtaining any necessary consents, permissions or other rights required for any use of the Work. + Affirmer understands and acknowledges that Creative Commons is not a party to this document and has no duty or obligation with respect to this CC0 or use of the Work. diff --git a/contrib/ccan/compiler/_info b/contrib/ccan/compiler/_info new file mode 100644 index 0000000..d60dff4 --- /dev/null +++ b/contrib/ccan/compiler/_info @@ -0,0 +1,64 @@ +#include "config.h" +#include <string.h> +#include <stdio.h> + +/** + * compiler - macros for common compiler extensions + * + * Abstracts away some compiler hints. Currently these include: + * - COLD + * For functions not called in fast paths (aka. cold functions) + * - PRINTF_FMT + * For functions which take printf-style parameters. + * - CONST_FUNCTION + * For functions which return the same value for same parameters. + * - NEEDED + * For functions and variables which must be emitted even if unused. + * - UNNEEDED + * For functions and variables which need not be emitted if unused. + * - UNUSED + * For parameters which are not used. + * - IS_COMPILE_CONSTANT() + * For using different tradeoffs for compiletime vs runtime evaluation. + * + * License: CC0 (Public domain) + * Author: Rusty Russell <rusty@rustcorp.com.au> + * + * Example: + * #include <ccan/compiler/compiler.h> + * #include <stdio.h> + * #include <stdarg.h> + * + * // Example of a (slow-path) logging function. + * static int log_threshold = 2; + * static void COLD PRINTF_FMT(2,3) + * logger(int level, const char *fmt, ...) + * { + * va_list ap; + * va_start(ap, fmt); + * if (level >= log_threshold) + * vfprintf(stderr, fmt, ap); + * va_end(ap); + * } + * + * int main(int argc, char *argv[]) + * { + * if (argc != 1) { + * logger(3, "Don't want %i arguments!\n", argc-1); + * return 1; + * } + * return 0; + * } + */ +int main(int argc, char *argv[]) +{ + /* Expect exactly one argument */ + if (argc != 2) + return 1; + + if (strcmp(argv[1], "depends") == 0) { + return 0; + } + + return 1; +} diff --git a/contrib/ccan/compiler/compiler.h b/contrib/ccan/compiler/compiler.h new file mode 100644 index 0000000..bce4f25 --- /dev/null +++ b/contrib/ccan/compiler/compiler.h @@ -0,0 +1,231 @@ +/* CC0 (Public domain) - see LICENSE file for details */ +#ifndef CCAN_COMPILER_H +#define CCAN_COMPILER_H +#include "config.h" + +#ifndef COLD +#if HAVE_ATTRIBUTE_COLD +/** + * COLD - a function is unlikely to be called. + * + * Used to mark an unlikely code path and optimize appropriately. + * It is usually used on logging or error routines. + * + * Example: + * static void COLD moan(const char *reason) + * { + * fprintf(stderr, "Error: %s (%s)\n", reason, strerror(errno)); + * } + */ +#define COLD __attribute__((__cold__)) +#else +#define COLD +#endif +#endif + +#ifndef NORETURN +#if HAVE_ATTRIBUTE_NORETURN +/** + * NORETURN - a function does not return + * + * Used to mark a function which exits; useful for suppressing warnings. + * + * Example: + * static void NORETURN fail(const char *reason) + * { + * fprintf(stderr, "Error: %s (%s)\n", reason, strerror(errno)); + * exit(1); + * } + */ +#define NORETURN __attribute__((__noreturn__)) +#else +#define NORETURN +#endif +#endif + +#ifndef PRINTF_FMT +#if HAVE_ATTRIBUTE_PRINTF +/** + * PRINTF_FMT - a function takes printf-style arguments + * @nfmt: the 1-based number of the function's format argument. + * @narg: the 1-based number of the function's first variable argument. + * + * This allows the compiler to check your parameters as it does for printf(). + * + * Example: + * void PRINTF_FMT(2,3) my_printf(const char *prefix, const char *fmt, ...); + */ +#define PRINTF_FMT(nfmt, narg) \ + __attribute__((format(__printf__, nfmt, narg))) +#else +#define PRINTF_FMT(nfmt, narg) +#endif +#endif + +#ifndef CONST_FUNCTION +#if HAVE_ATTRIBUTE_CONST +/** + * CONST_FUNCTION - a function's return depends only on its argument + * + * This allows the compiler to assume that the function will return the exact + * same value for the exact same arguments. This implies that the function + * must not use global variables, or dereference pointer arguments. + */ +#define CONST_FUNCTION __attribute__((__const__)) +#else +#define CONST_FUNCTION +#endif + +#ifndef PURE_FUNCTION +#if HAVE_ATTRIBUTE_PURE +/** + * PURE_FUNCTION - a function is pure + * + * A pure function is one that has no side effects other than it's return value + * and uses no inputs other than it's arguments and global variables. + */ +#define PURE_FUNCTION __attribute__((__pure__)) +#else +#define PURE_FUNCTION +#endif +#endif +#endif + +#if HAVE_ATTRIBUTE_UNUSED +#ifndef UNNEEDED +/** + * UNNEEDED - a variable/function may not be needed + * + * This suppresses warnings about unused variables or functions, but tells + * the compiler that if it is unused it need not emit it into the source code. + * + * Example: + * // With some preprocessor options, this is unnecessary. + * static UNNEEDED int counter; + * + * // With some preprocessor options, this is unnecessary. + * static UNNEEDED void add_to_counter(int add) + * { + * counter += add; + * } + */ +#define UNNEEDED __attribute__((__unused__)) +#endif + +#ifndef NEEDED +#if HAVE_ATTRIBUTE_USED +/** + * NEEDED - a variable/function is needed + * + * This suppresses warnings about unused variables or functions, but tells + * the compiler that it must exist even if it (seems) unused. + * + * Example: + * // Even if this is unused, these are vital for debugging. + * static NEEDED int counter; + * static NEEDED void dump_counter(void) + * { + * printf("Counter is %i\n", counter); + * } + */ +#define NEEDED __attribute__((__used__)) +#else +/* Before used, unused functions and vars were always emitted. */ +#define NEEDED __attribute__((__unused__)) +#endif +#endif + +#ifndef UNUSED +/** + * UNUSED - a parameter is unused + * + * Some compilers (eg. gcc with -W or -Wunused) warn about unused + * function parameters. This suppresses such warnings and indicates + * to the reader that it's deliberate. + * + * Example: + * // This is used as a callback, so needs to have this prototype. + * static int some_callback(void *unused UNUSED) + * { + * return 0; + * } + */ +#define UNUSED __attribute__((__unused__)) +#endif +#else +#ifndef UNNEEDED +#define UNNEEDED +#endif +#ifndef NEEDED +#define NEEDED +#endif +#ifndef UNUSED +#define UNUSED +#endif +#endif + +#ifndef IS_COMPILE_CONSTANT +#if HAVE_BUILTIN_CONSTANT_P +/** + * IS_COMPILE_CONSTANT - does the compiler know the value of this expression? + * @expr: the expression to evaluate + * + * When an expression manipulation is complicated, it is usually better to + * implement it in a function. However, if the expression being manipulated is + * known at compile time, it is better to have the compiler see the entire + * expression so it can simply substitute the result. + * + * This can be done using the IS_COMPILE_CONSTANT() macro. + * + * Example: + * enum greek { ALPHA, BETA, GAMMA, DELTA, EPSILON }; + * + * // Out-of-line version. + * const char *greek_name(enum greek greek); + * + * // Inline version. + * static inline const char *_greek_name(enum greek greek) + * { + * switch (greek) { + * case ALPHA: return "alpha"; + * case BETA: return "beta"; + * case GAMMA: return "gamma"; + * case DELTA: return "delta"; + * case EPSILON: return "epsilon"; + * default: return "**INVALID**"; + * } + * } + * + * // Use inline if compiler knows answer. Otherwise call function + * // to avoid copies of the same code everywhere. + * #define greek_name(g) \ + * (IS_COMPILE_CONSTANT(greek) ? _greek_name(g) : greek_name(g)) + */ +#define IS_COMPILE_CONSTANT(expr) __builtin_constant_p(expr) +#else +/* If we don't know, assume it's not. */ +#define IS_COMPILE_CONSTANT(expr) 0 +#endif +#endif + +#ifndef WARN_UNUSED_RESULT +#if HAVE_WARN_UNUSED_RESULT +/** + * WARN_UNUSED_RESULT - warn if a function return value is unused. + * + * Used to mark a function where it is extremely unlikely that the caller + * can ignore the result, eg realloc(). + * + * Example: + * // buf param may be freed by this; need return value! + * static char *WARN_UNUSED_RESULT enlarge(char *buf, unsigned *size) + * { + * return realloc(buf, (*size) *= 2); + * } + */ +#define WARN_UNUSED_RESULT __attribute__((__warn_unused_result__)) +#else +#define WARN_UNUSED_RESULT +#endif +#endif +#endif /* CCAN_COMPILER_H */ diff --git a/contrib/ccan/compiler/test/compile_fail-printf.c b/contrib/ccan/compiler/test/compile_fail-printf.c new file mode 100644 index 0000000..8f34ae5 --- /dev/null +++ b/contrib/ccan/compiler/test/compile_fail-printf.c @@ -0,0 +1,22 @@ +#include <ccan/compiler/compiler.h> + +static void PRINTF_FMT(2,3) my_printf(int x, const char *fmt, ...) +{ +} + +int main(int argc, char *argv[]) +{ + unsigned int i = 0; + + my_printf(1, "Not a pointer " +#ifdef FAIL + "%p", +#if !HAVE_ATTRIBUTE_PRINTF +#error "Unfortunately we don't fail if !HAVE_ATTRIBUTE_PRINTF." +#endif +#else + "%i", +#endif + i); + return 0; +} diff --git a/contrib/ccan/compiler/test/run-is_compile_constant.c b/contrib/ccan/compiler/test/run-is_compile_constant.c new file mode 100644 index 0000000..a66f2e1 --- /dev/null +++ b/contrib/ccan/compiler/test/run-is_compile_constant.c @@ -0,0 +1,15 @@ +#include <ccan/compiler/compiler.h> +#include <ccan/tap/tap.h> + +int main(int argc, char *argv[]) +{ + plan_tests(2); + + ok1(!IS_COMPILE_CONSTANT(argc)); +#if HAVE_BUILTIN_CONSTANT_P + ok1(IS_COMPILE_CONSTANT(7)); +#else + pass("If !HAVE_BUILTIN_CONSTANT_P, IS_COMPILE_CONSTANT always false"); +#endif + return exit_status(); +} |