调试技巧之 gcc/g++ -instrument-functions 参数【转载】
原文:http://www.cnblogs.com/wangkangluo1/archive/2012/07/09/2583228.html
参考
GCC 函式追蹤功能 finstrument-functions __attribute__ +用 Graphviz 可视化函数调用
gcc/g++使用-finstrument-functions來觀察code每個function的呼叫
http://www.logix.cz/michal/devel/CygProfiler/cyg-profile.c.xp
http://gcc.gnu.org/onlinedocs/gcc-4.3.3/gcc/Code-Gen-Options.html#Code-Gen-Options 官方参数说明
索引
因为项目太大,线程太多,gprof不可靠,于是找到了finstrument-functions
-finstrument-functions 會在每次進入與退出函式前呼叫 "__cyg_profile_func_enter" 與 "__cyg_profile_func_exit" 這兩個 hook function。等等,「進入」與「退出」是又何解?C Programming Language 最經典之處在於,雖然沒有定義語言實做的方式,但實際上 function call 皆以 stack frame 的形式存在,去年在「深入淺出 Hello World」Part II 有提過。所以上述那一大段英文就是說,如果我們不透過 GCC 內建函式 "__builtin_return_address" 取得 caller 與 callee 相關的動態位址,那麼仍可透過 -finstrument-functions,讓 GCC 合成相關的處理指令,讓我們得以追蹤。而看到 __cyg 開頭的函式,就知道是來自 Cygnus 的貢獻,在 gcc 2.x 內部設計可瞥見不少。
hello.c
#include <stdio.h> #define DUMP(func, call) printf("%s: func = %p, called by = %p/n", __FUNCTION__, func, call) void __attribute__((__no_instrument_function__)) __cyg_profile_func_enter(void *this_func, void *call_site) { DUMP(this_func, call_site); } void __attribute__((__no_instrument_function__)) __cyg_profile_func_exit(void *this_func, void *call_site) { DUMP(this_func, call_site); } main() { puts("Hello World!"); return 0; }
makefile
all:hello.o gcc -finstrument-functions -finstrument-functions hello.o -o hello hello.o: gcc -finstrument-functions -c hello.c clean: rm *.o hello -rf
运行:
./hello __cyg_profile_func_enter: func = 0x8048438, called by = 0x658dec/nHello World! __cyg_profile_func_exit: func = 0x8048438, called by = 0x658dec/n
完
hello.cc
#include <cstdlib> #include <cstdlib> #include <fstream> #include <iomanip> #include <iostream> using namespace std; #define DUMP(func, call) printf("%s: func = %p, called by = %p\n", __FUNCTION__, func, call) #ifdef __cplusplus extern "C" { #endif /* Static functions. */ static FILE *openlogfile (const char *filename) __attribute__ ((no_instrument_function)); static void closelogfile (void) __attribute__ ((no_instrument_function)); /* Note that these are linked internally by the compiler. * Don't call them directly! */ void __cyg_profile_func_enter (void *this_fn, void *call_site) __attribute__ ((no_instrument_function)); void __cyg_profile_func_exit (void *this_fn, void *call_site) __attribute__ ((no_instrument_function)); #ifdef __cplusplus }; #endif void __cyg_profile_func_enter (void *this_fn, void *call_site) { DUMP(this_fn, call_site); } void __cyg_profile_func_exit (void *this_fn, void *call_site) { DUMP(this_fn, call_site); } int main ( int argc, char *argv[] ) { cout << "\nProgram " << argv[0] << endl << endl; return EXIT_SUCCESS; } // ---------- end of function main ----------
makefile:
all: g++ -finstrument-functions hello.cc
运行:
./a.out __cyg_profile_func_enter: func = 0x80487ae, called by = 0x8048a3b __cyg_profile_func_enter: func = 0x8048714, called by = 0x80487d7 __cyg_profile_func_exit: func = 0x8048714, called by = 0x80487d7 __cyg_profile_func_exit: func = 0x80487ae, called by = 0x8048a3b __cyg_profile_func_enter: func = 0x8048882, called by = 0x658dec Program ./a.out __cyg_profile_func_exit: func = 0x8048882, called by = 0x658dec __cyg_profile_func_enter: func = 0x804881a, called by = 0x66e7f9 __cyg_profile_func_exit: func = 0x804881a, called by = 0x66e7f9
hello.c
#include <stdio.h> #include "test.h" #define DUMP(func, call) printf("%s: func = %p, called by = %p\n", __FUNCTION__, func, call) void __attribute__((__no_instrument_function__)) __cyg_profile_func_enter(void *this_func, void *call_site) { DUMP(this_func, call_site); } void __attribute__((__no_instrument_function__)) __cyg_profile_func_exit(void *this_func, void *call_site) { DUMP(this_func, call_site); } void test() { printf("nihao\n"); } main() { test(); puts("Hello World!"); return 0; }
makefile
CC=gcc44 all:hello.o $(CC) -g -finstrument-functions hello.o -o hello hello.o: $(CC) -g -finstrument-functions -finstrument-functions-exclude-function-list=test -c hello.c clean: rm *.o hello -rf
运行:
./hello __cyg_profile_func_enter: func = 0x804847e, called by = 0xb7e6adec nihao Hello World! __cyg_profile_func_exit: func = 0x804847e, called by = 0xb7e6adec
完