Commit 5b4485f5 authored by Petri Latvala's avatar Petri Latvala

lib: Introduce BUILD_BUG_ON_INVALID and igt_assume()

BUILD_BUG_ON_INVALID() is a macro that, like the kernel counterpart,
expands to an expression that generates no code. Useful for making
sure an expression is valid code while producing no side effects.

igt_assume() is an assert-like macro that is used to give hints to
static analysis of code. If static analysis is not used (as detected
by STATIC_ANALYSIS_BUILD), igt_assume() expands to a
BUILD_BUG_ON_INVALID, otherwise expands to an assert().

v2: Make sure the expression in igt_assume is still parsed without
    static analysis. (Chris)

v3: Also introduce BUILD_BUG_ON_INVALID as standalone
Signed-off-by: Petri Latvala's avatarPetri Latvala <petri.latvala@intel.com>
Cc: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Reviewed-by: Chris Wilson's avatarChris Wilson <chris@chris-wilson.co.uk>
parent d4199510
......@@ -30,6 +30,7 @@
#ifndef IGT_CORE_H
#define IGT_CORE_H
#include <assert.h>
#include <setjmp.h>
#include <stdbool.h>
#include <stdint.h>
......@@ -54,6 +55,30 @@
#endif
#endif
/**
* BUILD_BUG_ON_INVALID:
* @expr: Expression
*
* A macro that takes an expression and generates no code. Used for
* checking at build-time that an expression is valid code.
*/
#define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((long)(e))))
/**
* igt_assume:
* @expr: Condition to test
*
* An assert-like macro to be used for tautologies to give hints to
* static analysis of code. No-op if STATIC_ANALYSIS_BUILD is not
* defined, expands to an assert() if it is.
*/
#if STATIC_ANALYSIS_BUILD
#define igt_assume(e) assert(e)
#else
/* Make sure the expression is still parsed even though it generates no code */
#define igt_assume(e) BUILD_BUG_ON_INVALID(e)
#endif
extern const char* __igt_test_description __attribute__((weak));
extern bool __igt_plain_output;
extern char *igt_frame_dump_path;
......
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