调试技巧之 gcc/g++ -instrument-functions 参数

参考

     GCC 函式追蹤功能 finstrument-functions __attribute__ +用 Graphviz 可视化函数调用

     ibm 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

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索引

•       简介
•       c
•       c++
•       finstrument-functions-exclude-function-list=test 排除函数

     

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       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。

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c 

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 hellohello.o:    gcc  -finstrument-functions  -c hello.cclean:    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

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c++

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 __cplusplusextern "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};#endifvoid__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);}    intmain ( 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 = 0x658decProgram ./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

 

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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=gcc44all:hello.o        $(CC) -g -finstrument-functions  hello.o -o hellohello.o:        $(CC) -g -finstrument-functions -finstrument-functions-exclude-function-list=test -c hello.cclean:        rm *.o hello -rf

运行：

./hello__cyg_profile_func_enter: func = 0x804847e, called by = 0xb7e6adecnihaoHello World!__cyg_profile_func_exit: func = 0x804847e, called by = 0xb7e6adec

 

完