From d5b26d50fca744d1b19eb8c125b047c18c61ad94 Mon Sep 17 00:00:00 2001 From: Daniel Mack Date: Sun, 10 Jan 2016 18:11:22 +0100 Subject: macro.h: provide a switch-case statement generator for IN_SET Rather than walking a list of valid values one-by-one, generate a switch-case statement for the IN_SET() macro. This allows the compiler to further optimize its code output, possibly by generating jump tables. This effectively decreases the binary size slightly. The implementation is based on macro overloading depending on the number of arguments. h/t to the following post: https://stackoverflow.com/questions/11761703/overloading-macro-on-number-of-arguments --- src/basic/macro.h | 53 +++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 41 insertions(+), 12 deletions(-) (limited to 'src') diff --git a/src/basic/macro.h b/src/basic/macro.h index 5088e6720d..c529c6ecad 100644 --- a/src/basic/macro.h +++ b/src/basic/macro.h @@ -320,18 +320,47 @@ static inline unsigned long ALIGN_POWER2(unsigned long u) { #define SET_FLAG(v, flag, b) \ (v) = (b) ? ((v) | (flag)) : ((v) & ~(flag)) -#define IN_SET(x, y, ...) \ - ({ \ - static const typeof(y) _array[] = { (y), __VA_ARGS__ }; \ - const typeof(y) _x = (x); \ - unsigned _i; \ - bool _found = false; \ - for (_i = 0; _i < ELEMENTSOF(_array); _i++) \ - if (_array[_i] == _x) { \ - _found = true; \ - break; \ - } \ - _found; \ +#define CASE_F(X) case X: +#define CASE_F_1(CASE, X) CASE_F(X) +#define CASE_F_2(CASE, X, ...) CASE(X) CASE_F_1(CASE, __VA_ARGS__) +#define CASE_F_3(CASE, X, ...) CASE(X) CASE_F_2(CASE, __VA_ARGS__) +#define CASE_F_4(CASE, X, ...) CASE(X) CASE_F_3(CASE, __VA_ARGS__) +#define CASE_F_5(CASE, X, ...) CASE(X) CASE_F_4(CASE, __VA_ARGS__) +#define CASE_F_6(CASE, X, ...) CASE(X) CASE_F_5(CASE, __VA_ARGS__) +#define CASE_F_7(CASE, X, ...) CASE(X) CASE_F_6(CASE, __VA_ARGS__) +#define CASE_F_8(CASE, X, ...) CASE(X) CASE_F_7(CASE, __VA_ARGS__) +#define CASE_F_9(CASE, X, ...) CASE(X) CASE_F_8(CASE, __VA_ARGS__) +#define CASE_F_10(CASE, X, ...) CASE(X) CASE_F_9(CASE, __VA_ARGS__) +#define CASE_F_11(CASE, X, ...) CASE(X) CASE_F_10(CASE, __VA_ARGS__) +#define CASE_F_12(CASE, X, ...) CASE(X) CASE_F_11(CASE, __VA_ARGS__) +#define CASE_F_13(CASE, X, ...) CASE(X) CASE_F_12(CASE, __VA_ARGS__) +#define CASE_F_14(CASE, X, ...) CASE(X) CASE_F_13(CASE, __VA_ARGS__) +#define CASE_F_15(CASE, X, ...) CASE(X) CASE_F_14(CASE, __VA_ARGS__) +#define CASE_F_16(CASE, X, ...) CASE(X) CASE_F_15(CASE, __VA_ARGS__) +#define CASE_F_17(CASE, X, ...) CASE(X) CASE_F_16(CASE, __VA_ARGS__) +#define CASE_F_18(CASE, X, ...) CASE(X) CASE_F_17(CASE, __VA_ARGS__) +#define CASE_F_19(CASE, X, ...) CASE(X) CASE_F_18(CASE, __VA_ARGS__) +#define CASE_F_20(CASE, X, ...) CASE(X) CASE_F_19(CASE, __VA_ARGS__) + +#define GET_CASE_F(_1,_2,_3,_4,_5,_6,_7,_8,_9,_10,_11,_12,_13,_14,_15,_16,_17,_18,_19,_20,NAME,...) NAME +#define FOR_EACH_MAKE_CASE(...) \ + GET_CASE_F(__VA_ARGS__,CASE_F_20,CASE_F_19,CASE_F_18,CASE_F_17,CASE_F_16,CASE_F_15,CASE_F_14,CASE_F_13,CASE_F_12,CASE_F_11, \ + CASE_F_10,CASE_F_9,CASE_F_8,CASE_F_7,CASE_F_6,CASE_F_5,CASE_F_4,CASE_F_3,CASE_F_2,CASE_F_1) \ + (CASE_F,__VA_ARGS__) + +#define IN_SET(x, ...) \ + ({ \ + bool _found = false; \ + /* If the build breaks in the line below, you need to extend the case macros */ \ + static _unused_ char _static_assert__macros_need_to_be_extended[20 - sizeof((int[]){__VA_ARGS__})/sizeof(int)]; \ + switch(x) { \ + FOR_EACH_MAKE_CASE(__VA_ARGS__) \ + _found = true; \ + break; \ + default: \ + break; \ + } \ + _found; \ }) /* Define C11 thread_local attribute even on older gcc compiler -- cgit v1.2.3-54-g00ecf