8bc67ec2c0
It provides the following features: * verify correctness by comparing output to the C version. * detect failure to save and restore clobbered callee-saved registers. * detect 32-bit parameters being used as if they were 64-bit in x86-64 (the upper halves are not guaranteed to be zero - but in practice they very often are, which makes those bugs hard to spot otherwise). * easy benchmarking. Compile by running 'make checkasm'. Execute by running 'tests/checkasm/checkasm'. Optional arguments are '--bench' to run benchmarks for all functions, '--bench=<pattern>' to run benchmarks for all functions that starts with <pattern>, and '<integer>' to seed the PRNG for reproducible results. Contains unit tests for most h264pred functions to get started, more tests can be added afterwards using those as a reference. Loosely based on code from x264. Currently only supports x86 and x86-64, but additional architectures shouldn't be too much of an obstacle to add. Note that functions with floating point parameters or floating point return values are not supported. Some compiler-specific features or preprocessor hacks would likely be required to add support for that. Signed-off-by: Janne Grunau <janne-libav@jannau.net>
116 lines
4.3 KiB
C
116 lines
4.3 KiB
C
/*
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* Assembly testing and benchmarking tool
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* Copyright (c) 2015 Henrik Gramner
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* Copyright (c) 2008 Loren Merritt
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with Libav; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef CHECKASM_H
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#define CHECKASM_H
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#include <stdint.h>
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#include "config.h"
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#include "libavutil/avstring.h"
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#include "libavutil/lfg.h"
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#include "libavutil/timer.h"
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void checkasm_check_h264pred(void);
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intptr_t (*checkasm_check_func(intptr_t (*func)(), const char *name, ...))() av_printf_format(2, 3);
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int checkasm_bench_func(void);
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void checkasm_fail_func(const char *msg, ...) av_printf_format(1, 2);
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void checkasm_update_bench(int iterations, uint64_t cycles);
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void checkasm_report(const char *name, ...) av_printf_format(1, 2);
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extern AVLFG checkasm_lfg;
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#define rnd() av_lfg_get(&checkasm_lfg)
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static av_unused intptr_t (*func_ref)();
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static av_unused intptr_t (*func_new)();
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#define BENCH_RUNS 1000 /* Trade-off between accuracy and speed */
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/* Decide whether or not the specified function needs to be tested */
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#define check_func(func, ...) ((func_new = (intptr_t (*)())func) &&\
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(func_ref = checkasm_check_func(func_new, __VA_ARGS__)))
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/* Indicate that the current test has failed */
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#define fail() checkasm_fail_func("%s:%d", av_basename(__FILE__), __LINE__)
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/* Print the test outcome */
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#define report(...) checkasm_report("" __VA_ARGS__)
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/* Call the reference function */
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#define call_ref(...) func_ref(__VA_ARGS__)
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#if ARCH_X86 && HAVE_YASM
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/* Verifies that clobbered callee-saved registers are properly saved and restored */
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intptr_t checkasm_checked_call(intptr_t (*func)(), ...);
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#endif
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/* Call the function */
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#if ARCH_X86_64 && HAVE_YASM
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/* Evil hack: detect incorrect assumptions that 32-bit ints are zero-extended to 64-bit.
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* This is done by clobbering the stack with junk around the stack pointer and calling the
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* assembly function through x264_checkasm_call with added dummy arguments which forces all
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* real arguments to be passed on the stack and not in registers. For 32-bit arguments the
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* upper half of the 64-bit register locations on the stack will now contain junk which will
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* cause misbehaving functions to either produce incorrect output or segfault. Note that
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* even though this works extremely well in practice, it's technically not guaranteed
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* and false negatives is theoretically possible, but there can never be any false positives.
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*/
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void checkasm_stack_clobber(uint64_t clobber, ...);
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#define CLOB (UINT64_C(0xdeadbeefdeadbeef))
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#define call_new(...) (checkasm_stack_clobber(CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,\
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CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB,CLOB),\
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checkasm_checked_call(func_new, 0, 0, 0, 0, 0, __VA_ARGS__))
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#elif ARCH_X86_32 && HAVE_YASM
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#define call_new(...) checkasm_checked_call(func_new, __VA_ARGS__)
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#else
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#define call_new(...) func_new(__VA_ARGS__)
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#endif
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/* Benchmark the function */
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#ifdef AV_READ_TIME
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#define bench_new(...)\
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do {\
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if (checkasm_bench_func()) {\
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intptr_t (*tfunc)() = func_new;\
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uint64_t tsum = 0;\
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int ti, tcount = 0;\
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for (ti = 0; ti < BENCH_RUNS; ti++) {\
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uint64_t t = AV_READ_TIME();\
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tfunc(__VA_ARGS__);\
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tfunc(__VA_ARGS__);\
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tfunc(__VA_ARGS__);\
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tfunc(__VA_ARGS__);\
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t = AV_READ_TIME() - t;\
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if (t*tcount <= tsum*4 && ti > 0) {\
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tsum += t;\
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tcount++;\
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}\
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}\
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checkasm_update_bench(tcount, tsum);\
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}\
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} while (0)
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#else
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#define bench_new(...)
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#endif
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#endif
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