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checkasm.h
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1 /*
2  * Assembly testing and benchmarking tool
3  * Copyright (c) 2015 Henrik Gramner
4  * Copyright (c) 2008 Loren Merritt
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License along
19  * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
21  */
22 
23 #ifndef CHECKASM_H
24 #define CHECKASM_H
25 
26 #include <stdint.h>
27 #include "config.h"
28 #include "libavutil/avstring.h"
29 #include "libavutil/lfg.h"
30 #include "libavutil/timer.h"
31 
32 void checkasm_check_bswapdsp(void);
33 void checkasm_check_h264pred(void);
34 void checkasm_check_h264qpel(void);
35 
36 void *checkasm_check_func(void *func, const char *name, ...) av_printf_format(2, 3);
37 int checkasm_bench_func(void);
38 void checkasm_fail_func(const char *msg, ...) av_printf_format(1, 2);
39 void checkasm_update_bench(int iterations, uint64_t cycles);
40 void checkasm_report(const char *name, ...) av_printf_format(1, 2);
41 
42 extern AVLFG checkasm_lfg;
43 #define rnd() av_lfg_get(&checkasm_lfg)
44 
45 static av_unused void *func_ref, *func_new;
46 
47 #define BENCH_RUNS 1000 /* Trade-off between accuracy and speed */
48 
49 /* Decide whether or not the specified function needs to be tested */
50 #define check_func(func, ...) (func_ref = checkasm_check_func((func_new = func), __VA_ARGS__))
51 
52 /* Declare the function prototype. The first argument is the return value, the remaining
53  * arguments are the function parameters. Naming parameters is optional. */
54 #define declare_func(ret, ...) declare_new(ret, __VA_ARGS__) typedef ret func_type(__VA_ARGS__)
55 
56 /* Indicate that the current test has failed */
57 #define fail() checkasm_fail_func("%s:%d", av_basename(__FILE__), __LINE__)
58 
59 /* Print the test outcome */
60 #define report checkasm_report
61 
62 /* Call the reference function */
63 #define call_ref(...) ((func_type *)func_ref)(__VA_ARGS__)
64 
65 #if ARCH_X86 && HAVE_YASM
66 /* Verifies that clobbered callee-saved registers are properly saved and restored */
67 void checkasm_checked_call(void *func, ...);
68 
69 #if ARCH_X86_64
70 /* Evil hack: detect incorrect assumptions that 32-bit ints are zero-extended to 64-bit.
71  * This is done by clobbering the stack with junk around the stack pointer and calling the
72  * assembly function through checked_call() with added dummy arguments which forces all
73  * real arguments to be passed on the stack and not in registers. For 32-bit arguments the
74  * upper half of the 64-bit register locations on the stack will now contain junk which will
75  * cause misbehaving functions to either produce incorrect output or segfault. Note that
76  * even though this works extremely well in practice, it's technically not guaranteed
77  * and false negatives is theoretically possible, but there can never be any false positives.
78  */
79 void checkasm_stack_clobber(uint64_t clobber, ...);
80 #define declare_new(ret, ...) ret (*checked_call)(void *, int, int, int, int, int, __VA_ARGS__)\
81  = (void *)checkasm_checked_call;
82 #define CLOB (UINT64_C(0xdeadbeefdeadbeef))
83 #define call_new(...) (checkasm_stack_clobber(CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,\
84  CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB),\
85  checked_call(func_new, 0, 0, 0, 0, 0, __VA_ARGS__))
86 #elif ARCH_X86_32
87 #define declare_new(ret, ...) ret (*checked_call)(void *, __VA_ARGS__) = (void *)checkasm_checked_call;
88 #define call_new(...) checked_call(func_new, __VA_ARGS__)
89 #endif
90 #else
91 #define declare_new(ret, ...)
92 /* Call the function */
93 #define call_new(...) ((func_type *)func_new)(__VA_ARGS__)
94 #endif
95 
96 /* Benchmark the function */
97 #ifdef AV_READ_TIME
98 #define bench_new(...)\
99  do {\
100  if (checkasm_bench_func()) {\
101  func_type *tfunc = func_new;\
102  uint64_t tsum = 0;\
103  int ti, tcount = 0;\
104  for (ti = 0; ti < BENCH_RUNS; ti++) {\
105  uint64_t t = AV_READ_TIME();\
106  tfunc(__VA_ARGS__);\
107  tfunc(__VA_ARGS__);\
108  tfunc(__VA_ARGS__);\
109  tfunc(__VA_ARGS__);\
110  t = AV_READ_TIME() - t;\
111  if (t*tcount <= tsum*4 && ti > 0) {\
112  tsum += t;\
113  tcount++;\
114  }\
115  }\
116  checkasm_update_bench(tcount, tsum);\
117  }\
118  } while (0)
119 #else
120 #define bench_new(...) while(0)
121 #endif
122 
123 #endif
Definition: lfg.h:25
void * checkasm_check_func(void *func, const char *name,...) av_printf_format(2
void checkasm_check_bswapdsp(void)
Definition: bswapdsp.c:59
void checkasm_check_h264pred(void)
Definition: h264pred.c:232
void checkasm_check_h264qpel(void)
Definition: h264qpel.c:50
high precision timer, useful to profile code
void int checkasm_bench_func(void)
Definition: checkasm.c:436
void void checkasm_update_bench(int iterations, uint64_t cycles)
Definition: checkasm.c:461
void checkasm_fail_func(const char *msg,...) av_printf_format(1
#define av_printf_format(fmtpos, attrpos)
Definition: attributes.h:148
static av_unused void * func_ref
Definition: checkasm.h:45
int(* func)(AVBPrint *dst, const char *in, const char *arg)
Definition: jacosubdec.c:67
void AVLFG checkasm_lfg
Definition: checkasm.c:144
void checkasm_report(const char *name,...) av_printf_format(1
static av_unused void * func_new
Definition: checkasm.h:45
#define av_unused
Definition: attributes.h:118
const char * name
Definition: opengl_enc.c:103