diff options
Diffstat (limited to 'payloads/libpayload/include/compiler.h')
| -rw-r--r-- | payloads/libpayload/include/compiler.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/payloads/libpayload/include/compiler.h b/payloads/libpayload/include/compiler.h index a830239009..fa9c78bd36 100644 --- a/payloads/libpayload/include/compiler.h +++ b/payloads/libpayload/include/compiler.h @@ -26,4 +26,19 @@ #define __always_unused __attribute__((unused)) #define __must_check __attribute__((warn_unused_result)) +/* This evaluates to the type of the first expression, unless that is constant + in which case it evalutates to the type of the second. This is useful when + assigning macro parameters to temporary variables, because that would + normally circumvent the special loosened type promotion rules for integer + literals. By using this macro, the promotion can happen at the time the + literal is assigned to the temporary variable. If the literal doesn't fit in + the chosen type, -Werror=overflow will catch it, so this should be safe. */ +#define __TYPEOF_UNLESS_CONST(expr, fallback_expr) typeof( \ + __builtin_choose_expr(__builtin_constant_p(expr), fallback_expr, expr)) + +/* This creates a unique local variable name for use in macros. */ +#define __TMPNAME_3(i) __tmpname_##i +#define __TMPNAME_2(i) __TMPNAME_3(i) +#define __TMPNAME __TMPNAME_2(__COUNTER__) + #endif |