一、关于gcov工具

gcov伴随gcc 发布。gcc编译加入-fprofile-arcs -ftest-coverage

参数生成二进制程序，执行测试用例生成代码覆盖率信息。

1、如何使用gcov

用GCC编译的时候加上-fprofile-arcs -ftest-coverage选项，链接的时候也加上。

fprofile-arcs参数使gcc创建一个程序的流图，之后找到适合图的生成树。只有不在生成树中的弧被操纵(instrumented)：gcc

添加了代码来清点这

些弧执行的次数。当这段弧是一个块的唯一出口或入口时，操纵工具代码(instrumentation

code)将会添加到块中，否则创建一个基础块来包含操纵

工具代码。gcov主要使用.gcno和.gcda两个文件。

.gcno是由-ftest-coverage产生的，它包含了重建基本块图和相应的块的源码的行号的信息。

.gcda是由加了-fprofile-arcs编译参数的编译后的文件运行所产生的，它包含了弧跳变的次数和其他的概要信息。

Gcov执行函数覆盖、语句覆盖和分支覆盖。

举个例子,程序代码由main.c和tmp.c两个文件组成，编译、链接、运行程序

编译：gcc -fprofile-arcs -ftest-coverage -o myapp main.c tmp.c

运行：./myapp

然后 输入

命令： gcov main.c,gcov tmp.c

这个时候当前目录下有了新的文档main.c.gcov,和tmp.c.gcov

若想保存覆盖率文件，上述命令修改为：

命令：gcov main.c >>yourfilename,gcov tmp.c >>yourfilename

查看结果：

-:

65:/***************************************************************************************

-:   66: * name         : main

-:   67: * return       : 0 OK

-:   68: *                other ERROR

-:   69: * history      : 2006-06-13

-:

70:****************************************************************************************/

-:   71:int main( int argc, char *argv[]

)                                                      /* the entrance

for program

*/

function main called 4 returned 100% blocks executed 81%

4:   72:{

4:   73:        int loop = 0 ;

4:   74:        int ret = OK ;

4:   75:        int empty_line = 0 ;

4:   76:        int code_line = 0 ;

4:   77:        int annotation_line = 0 ;

4:   78:        struct stat file_stat

;                                                         /* use for

file state */

4:   79:        char recu_name[256] ;

4:   80:        char *pwd = NULL ;

4:   81:        char *tmp = NULL ;

-:   82:

4:   83:        if( argc = MAX_FILE

){                                    /* file size larger than max size

*/

#####:   98:                        printf( "file [%s] size is

over 64K! \ncontinue....\n", argv[loop] ) ;

#####:   99:                        continue ;

-: 100:                }

##### 这就是表示没跑到的

各个参数使用如下：

gcov [-b] [-c] [-v] [-n] [-l] [-f] [-o directory] sourcefile

-b

Write branch frequencies to the output file, and write branch

summary info to the standard output. This option allows you to

see how often each branch in your program was taken.

//b(ranch),分支测试

-c

Write branch frequencies as the number of branches taken, rather

than the percentage of branches taken.

-v

Display the gcov version number (on the standard error stream).

//太简单了吧,我上面用了

-n

Do not create the gcov output file.

-l

Create long file names for included source files. For example, if

the header file `x.h' contains code, and was included in the

file `a.c', then running gcov on the file `a.c' will produce an

output file called `a.c.x.h.gcov' instead of `x.h.gcov'. This can

be useful if `x.h' is included in multiple source files.

-f

Output summaries for each function in addition to the file level

summary.

-o

The directory where the object files live. Gcov will search for

`.bb', `.bbg', and `.da' files in this directory.

新版的是这么说的

-o directory│file

--object-directory directory

--object-file file

Specify either the directory containing the gcov data files,

or the

object path name. The .gcno, and .gcda data files are

searched for

using this option. If a directory is specified, the data

files are

in that directory and named after the source file name,

without its

extension. If a file is specified here, the data files are

named

after that file, without its extension. If this option is

not sup-

plied, it defaults to the current directory.

其他的更有新版的-u,

-u

--unconditional-branches

When branch counts are given, include those of unconditional

branches. Unconditional branches are normally not

interesting.

-p

--preserve-paths

p; Preserve complete path information in the

names of generated .gcov

files. Without this option, just the filename component is

used.

With this option, all directories are used, with ’/’

characters

translated to ’#’ characters, ’.’ directory components

removed and

’..’ components renamed to ’^’. This is useful if

sourcefiles are

in several different directories. It also affects the -l

option.

二、关于lcov

Lcov则是上的gcov 结果展现的一个前端，可以将覆盖率信息转换成html展现。

1、如何使用lcov

Makefile 在编译和link环节都加入 -fprofile-arcs -ftest-coverage 选项

收集覆盖率数据生成app.info文件

命令：cov --directory .   --capture --output-file myapp.info

Capturing coverage data from .

Found gcov version: 3.4.6

Scanning . for .gcda files ...

Found 1 data files in .

Processing ./TestQuery.gcda

Finished .info-file creation

转换成html格式

命令：genhtml -o results app.info

Reading data file app.info

Found 18 entries.

Found common filename prefix "/home/search/isearch_yb/src"

Writing .css and .png files.

Generating output.

Processing file cpp/core/basis/GlobalDef.h

Processing file cpp/core/search/QueryCache.h

...

Writing directory view page.

Overall coverage rate: 117 of 514 lines (22.8%)

2、查看html文件

html包含代码覆盖的详细信息

更多命令选项

参考资料

1、