+++ /dev/null
-/* 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 */
projects / bcachefs-tools-debian / blobdiff