gcc - gprof 不为需要合理时间执行的程序产生任何输出

Question

我知道以前有人问过类似的问题，但是:

关于 gprof produces empty output 我在 Windows 10 上使用来自 MSYS2 的 GCC 10.2.0，即它是 MingW64 发行版。我还将 -no-pie 添加到链接器参数中，但仍然没有结果。 GNU Prof 的版本是 2.36.1

关于 gprof gives no output 我正在一个明确需要时间执行的程序上执行它。

该程序是来自 this tutorial 的代码，复制如下:

//test_gprof.c
#include<stdio.h>

void new_func1(void)
{
    printf("\n Inside new_func1()\n");
    int i = 0;

    for(;i<0xffffffee;i++);

    return;
}

void func1(void)
{
    printf("\n Inside func1 \n");
    int i = 0;

    for(;i<0xffffffff;i++);
    new_func1();

    return;
}

static void func2(void)
{
    printf("\n Inside func2 \n");
    int i = 0;

    for(;i<0xffffffaa;i++);
    return;
}

int main(void)
{
    printf("\n Inside main()\n");
    int i = 0;

    for(;i<0xffffff;i++);
    func1();
    func2();

    return 0;
}

我正在使用 Code::Blocks 进行构建。我已经尝试过 MSYS2 的 32 位和 64 位版本的 MingW。我已将所有内容升级到可用软件包的最新版本。
Code::Blocks 构建日志的输出:

g++.exe -pg -c C:\Users\david\Documents\GameDev\CPPTESTS\main.cpp -o obj\Debug\CPPTESTS\main.o
g++.exe -o CPPTESTS-d.exe obj\Debug\CPPTESTS\main.o -pg -lgmon -no-pie

程序编译并成功执行。执行后，会生成一个gmon.out 文件。执行 gprof 来解释这个文件:

 gprof CPPTests-d.exe gmon.out > gprofoutput.txt

在 gprofoutput.txt 中产生以下内容:

Flat profile:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total           
 time   seconds   seconds    calls  Ts/call  Ts/call  name    

 %         the percentage of the total running time of the
time       program used by this function.

cumulative a running sum of the number of seconds accounted
 seconds   for by this function and those listed above it.

 self      the number of seconds accounted for by this
seconds    function alone.  This is the major sort for this
           listing.

calls      the number of times this function was invoked, if
           this function is profiled, else blank.

 self      the average number of milliseconds spent in this
ms/call    function per call, if this function is profiled,
       else blank.

 total     the average number of milliseconds spent in this
ms/call    function and its descendents per call, if this
       function is profiled, else blank.

name       the name of the function.  This is the minor sort
           for this listing. The index shows the location of
       the function in the gprof listing. If the index is
       in parenthesis it shows where it would appear in
       the gprof listing if it were to be printed.

Copyright (C) 2012-2021 Free Software Foundation, Inc.

Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.

             Call graph (explanation follows)


granularity: each sample hit covers 4 byte(s) no time propagated

index % time    self  children    called     name

 This table describes the call tree of the program, and was sorted by
 the total amount of time spent in each function and its children.

 Each entry in this table consists of several lines.  The line with the
 index number at the left hand margin lists the current function.
 The lines above it list the functions that called this function,
 and the lines below it list the functions this one called.
 This line lists:
     index  A unique number given to each element of the table.
        Index numbers are sorted numerically.
        The index number is printed next to every function name so
        it is easier to look up where the function is in the table.

     % time This is the percentage of the `total' time that was spent
        in this function and its children.  Note that due to
        different viewpoints, functions excluded by options, etc,
        these numbers will NOT add up to 100%.

     self   This is the total amount of time spent in this function.

     children   This is the total amount of time propagated into this
        function by its children.

     called This is the number of times the function was called.
        If the function called itself recursively, the number
        only includes non-recursive calls, and is followed by
        a `+' and the number of recursive calls.

     name   The name of the current function.  The index number is
        printed after it.  If the function is a member of a
        cycle, the cycle number is printed between the
        function's name and the index number.


 For the function's parents, the fields have the following meanings:

     self   This is the amount of time that was propagated directly
        from the function into this parent.

     children   This is the amount of time that was propagated from
        the function's children into this parent.

     called This is the number of times this parent called the
        function `/' the total number of times the function
        was called.  Recursive calls to the function are not
        included in the number after the `/'.

     name   This is the name of the parent.  The parent's index
        number is printed after it.  If the parent is a
        member of a cycle, the cycle number is printed between
        the name and the index number.

 If the parents of the function cannot be determined, the word
 `<spontaneous>' is printed in the `name' field, and all the other
 fields are blank.

 For the function's children, the fields have the following meanings:

     self   This is the amount of time that was propagated directly
        from the child into the function.

     children   This is the amount of time that was propagated from the
        child's children to the function.

     called This is the number of times the function called
        this child `/' the total number of times the child
        was called.  Recursive calls by the child are not
        listed in the number after the `/'.

     name   This is the name of the child.  The child's index
        number is printed after it.  If the child is a
        member of a cycle, the cycle number is printed
        between the name and the index number.

 If there are any cycles (circles) in the call graph, there is an
 entry for the cycle-as-a-whole.  This entry shows who called the
 cycle (as parents) and the members of the cycle (as children.)
 The `+' recursive calls entry shows the number of function calls that
 were internal to the cycle, and the calls entry for each member shows,
 for that member, how many times it was called from other members of
 the cycle.

Copyright (C) 2012-2021 Free Software Foundation, Inc.

Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.

Index by function name

你可以看到它完全是空的。此外，如果我在十六进制编辑器中打开 gmon.out，里面大部分是空白的，这是第一位:

F0 14 C5 00 18 8A C5 00 B4 3A 00 00 79 18 05 00 64 00 00 00 96 1A C5 00 A7 16 C5 00 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 05 00 FE 00 5D 00 E2 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 07 00 C6 01 A5 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 06 00 E5 00 77 00 F5 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

然后最后是以下内容:

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 E4 15 C5 00 6C 89 C5 00 01 00 00 00 14 16 C5 00 6C 89 C5 00 01 00 00 00 2C 16 C5 00 DB 15 C5 00 01 00 00 00 48 16 C5 00 6C 89 C5 00 01 00 00 00 84 16 C5 00 6C 89 C5 00 01 00 00 00 A0 16 C5 00 0A 16 C5 00 01 00 00 00 A4 16 C5 00 3C 16 C5 00 01 00 00 00

其余的是几千字节的 00 。
我已经尝试了所有我可以在谷歌找到的关于让它工作的方法。最初我在一个项目的实际代码上执行它时遇到了麻烦，但我不得不使用上面的代码，因为似乎我做错了一些我无法弄清楚的事情。
任何帮助，将不胜感激。
编辑
我设法在 gmon.out 中生成了用 gprof 正确解析的结果，并为我的测试程序中的所有函数提供了计时。没有做任何改变，甚至没有关闭 MSYS2 终端(我放弃了 Code::Blocks 以确保它不是问题)，然后我用相同的命令重新编译程序，再次执行它，并返回一个空结果。
我不清楚它是在编译过程中发生了什么(很难相信，它是使用终端历史记录中的最后一个命令编译的)，还是在我执行它时在我的机器上发生了什么。或者如果 gprof 翻译 gmon.out 文件有问题。
编辑 2
我在从未用于开发的另一台机器(它是类似的 Windows 10 Surface Pro)上执行了该程序。当通过 gprof 解析时，它产生的 gmon.out 似乎也没有结果。
编辑 3
我已经厌倦了 gcc 和 g++ 的相同结果。我尝试过单独的编译和链接步骤，或者同时进行。我也试过链接到 -lgmon 或不链接。解析 gprof 时，所有结果都相同。
自从它工作的一个随机时间以来，我一直无法再次获得结果。
编辑 4
我用 -g 和 -pg 编译了程序，然后通过 VTune 运行它。我可以在热点分析中看到正在调用与分析器相关的函数调用。
这是整个被调用者堆栈。您可以看到正在调用与配置文件相关的函数调用 profthr_func 和 get_thrpc。

Callees CPU Time: Total CPU Time: Self
BaseThreadInitThunk 100.0%  0s
  _tmainCRTStartup  99.1%   0s
    main    99.1%   0.016s
      func1 65.8%   20.521s
        new_func1   32.8%   20.456s
      func2 33.2%   20.695s
  profthr_func  0.6%    0.009s
    WaitForSingleObject 0.4%    0.231s
    get_thrpc   0.2%    0s
      SwitchToThread    0.2%    0.116s
      TlsGetValue   0.0%    0.002s
      GetLastError  0.0%    0.001s
      SwitchToThread    0.0%    0.001s
      GetLastError  0.0%    0.001s
      [Outside any known module]    0.0%    0.001s
      func@0x4b308730   0.0%    0.000s
      TlsGetValue   0.0%    0.000s
  get_thrpc 0.4%    0s
    GetThreadContext    0.3%    0.214s
    GetLastError    0.0%    0.006s
    TlsGetValue 0.0%    0.000s
  [Outside any known module]    0.0%    0.002s
  SuspendThread 0.0%    0.001s
  [Unknown stack frame(s)]  0.0%    0s
    profthr_func    0.0%    0s
      WaitForSingleObject   0.0%    0.000s

然后是所有功能及其来源等:

Function                    CPU Time: Total CPU Time: Self  Module          Function (Full)             Source File Start Address
BaseThreadInitThunk         100.0%          0s              kernel32.dll    BaseThreadInitThunk         [Unknown]   0x6b81fa10
func@0x4b2e7a03             100.0%          0s              ntdll.dll       func@0x4b2e7a03             [Unknown]   0x4b2e7a03
func@0x4b2e7a1f             100.0%          0s              ntdll.dll       func@0x4b2e7a1f             [Unknown]   0x4b2e7a1f
_tmainCRTStartup            99.1%           0s              CPPTESTS-d.exe  _tmainCRTStartup            crtexe.c    0x401170
main                        99.1%           0.016s          CPPTESTS-d.exe  main                        main.cpp    0x40165c
func1                       65.8%           20.521s         CPPTESTS-d.exe  func1(void)                 main.cpp    0x4015fd
func2                       33.2%           20.695s         CPPTESTS-d.exe  func2                       main.cpp    0x40162f
new_func1                   32.8%           20.456s         CPPTESTS-d.exe  new_func1(void)             main.cpp    0x4015d0
profthr_func                0.6%            0.009s          CPPTESTS-d.exe  profthr_func                profil.c    0x408620
get_thrpc                   0.5%            0s              CPPTESTS-d.exe  get_thrpc                   profil.c    0x4085c0
WaitForSingleObject         0.4%            0.231s          KernelBase.dll  WaitForSingleObject         [Unknown]   0x10110440
GetThreadContext            0.3%            0.214s          KernelBase.dll  GetThreadContext            [Unknown]   0x101b61a0
SwitchToThread              0.2%            0.116s          KernelBase.dll  SwitchToThread              [Unknown]   0x100f5b40
GetLastError                0.0%            0.007s          kernel32.dll    GetLastError                [Unknown]   0x6b81e010
[Outside any known module]  0.0%            0.002s          [Unknown]       [Outside any known module]  [Unknown]   0
TlsGetValue                 0.0%            0.002s          KernelBase.dll  TlsGetValue                 [Unknown]   0x101193a0
SuspendThread               0.0%            0.001s          kernel32.dll    SuspendThread               [Unknown]   0x6b834e90
SwitchToThread              0.0%            0.001s          kernel32.dll    SwitchToThread              [Unknown]   0x6b817cc0
GetLastError                0.0%            0.001s          KernelBase.dll  GetLastError                [Unknown]   0x10110580
TlsGetValue                 0.0%            0.000s          kernel32.dll    TlsGetValue                 [Unknown]   0x6b81df20
func@0x4b308730             0.0%            0.000s          ntdll.dll       func@0x4b308730             [Unknown]   0x4b308730
[Unknown stack frame(s)]    0.0%            0s              [Unknown]       [Unknown stack frame(s)]    [Unknown]   0

我不确定这些信息是否有助于解决我的问题。 gmon.out 文件再次通过 gprof 解析时，没有任何信息。
我读过 this answer to a question about how gprof works ，所以我希望对 main 、 func1 、 func2 和 new_func1 的调用会带有某种乐器调用？
我运行了 VTune 并检查了 Threading 选项，并注意到 gprof 似乎是通过一个新线程来完成它的，这与我上面的理解不同。但是，它并没有解释为什么我曾经得到一些输出并且无法重新创建它。
但是，在 Vtune 中，我没有看到对 mcount 的调用，我认为这是 gprof 的工作方式。它确实向我展示了来自 -pg 标志的分析 内容 的点点滴滴(如您在上面的调用堆栈和函数列表中所见)。
编辑 5
我已经上传了我的 compiled program 并且它是 gmon.out 以防它帮助任何人帮助回答问题。
编辑 6
我重新安装了 MSYS2，希望能解决问题。它没有。
编辑 7
我试过与 -static -static-libgcc -static-libstdc++ 链接。它没有效果。
编辑 8
我已经用 -d 标志执行了 gprof。 Debug output can be found here 。但这对我来说大多只是胡言乱语。
编辑 9
我已经在 MSYS2 之外直接安装了 Mingw-Builds 并在 i686 和 86_64 版本中测试了 8.1.0 版、Dwarf 和 SJLJ。用这个版本的 G++ 编译和链接后，生成了一个 gmon.out 文件，但是 gprof 给出了以下错误(或者是数字的变体):

BFD: Dwarf Error: Could not find abbrev number 108.

但是生成的输出有效。我还检查了 8.1.0 编译的程序 gmon.out 可以被较新的 MSYS2 gprof 解析而没有问题。因此，问题似乎出在较新版本的 Mingw64 上。
Gprof 报告版本 2.30，G++ 报告版本 8.1.0。
编辑 10
我已经尝试在干净的 Windows 7 Virtual Box 机器上编译和运行 gprof 并获得相同的结果。所以我不是我的操作系统(Windows 10)或我的特定计算机。
看起来这个问题在这里没有得到回答。如果我弄清楚了，我会回答这个问题。在那之前，我已经在 MSYS2 tracker 和 Mingw64 tracker 上创建了问题。
编辑 11
我现在一直在研究以下代码:

#include <iostream>

bool is_prime(const int& number)
{
    if(number == 0 || number == 1)
        return false;
    else
    {
        for(int i = 2; i <= number / 2; ++i)
        {
            if(number % i == 0)
            {
                return false;
            }
        }
    }

    return true;
}

int main()
{
    int low = 0;
    int high = 300000;

    while(low < high)
    {
        if(is_prime(low))
            std::cout << low << ", ";

        ++low;
    }

    std::cout << std::endl;
    return 0;
}

使用与之前的 g++ -g -pg -O0 main.cpp -o CPPTESTS-d.exe 相同的编译器标志 objdump -d CPPTESTS-d.exe 为我提供了来自 main 和 is_prime 部分的以下内容:

004015d0 <__Z8is_primeRKi>:
  4015d0:   55                      push   %ebp
  4015d1:   89 e5                   mov    %esp,%ebp
  4015d3:   83 ec 10                sub    $0x10,%esp
  4015d6:   e8 a5 15 00 00          call   402b80 <_mcount>
  4015db:   8b 45 08                mov    0x8(%ebp),%eax
  4015de:   8b 00                   mov    (%eax),%eax
  4015e0:   85 c0                   test   %eax,%eax
  4015e2:   74 0a                   je     4015ee <__Z8is_primeRKi+0x1e>
  4015e4:   8b 45 08                mov    0x8(%ebp),%eax
  4015e7:   8b 00                   mov    (%eax),%eax
  4015e9:   83 f8 01                cmp    $0x1,%eax
  4015ec:   75 07                   jne    4015f5 <__Z8is_primeRKi+0x25>
  4015ee:   b8 00 00 00 00          mov    $0x0,%eax
  4015f3:   eb 3b                   jmp    401630 <__Z8is_primeRKi+0x60>
  4015f5:   c7 45 fc 02 00 00 00    movl   $0x2,-0x4(%ebp)
  4015fc:   8b 45 08                mov    0x8(%ebp),%eax
  4015ff:   8b 00                   mov    (%eax),%eax
  401601:   89 c2                   mov    %eax,%edx
  401603:   c1 ea 1f                shr    $0x1f,%edx
  401606:   01 d0                   add    %edx,%eax
  401608:   d1 f8                   sar    %eax
  40160a:   39 45 fc                cmp    %eax,-0x4(%ebp)
  40160d:   7f 1c                   jg     40162b <__Z8is_primeRKi+0x5b>
  40160f:   8b 45 08                mov    0x8(%ebp),%eax
  401612:   8b 00                   mov    (%eax),%eax
  401614:   99                      cltd   
  401615:   f7 7d fc                idivl  -0x4(%ebp)
  401618:   89 d0                   mov    %edx,%eax
  40161a:   85 c0                   test   %eax,%eax
  40161c:   75 07                   jne    401625 <__Z8is_primeRKi+0x55>
  40161e:   b8 00 00 00 00          mov    $0x0,%eax
  401623:   eb 0b                   jmp    401630 <__Z8is_primeRKi+0x60>
  401625:   83 45 fc 01             addl   $0x1,-0x4(%ebp)
  401629:   eb d1                   jmp    4015fc <__Z8is_primeRKi+0x2c>
  40162b:   b8 01 00 00 00          mov    $0x1,%eax
  401630:   c9                      leave  
  401631:   c3                      ret    

00401632 <_main>:
  401632:   8d 4c 24 04             lea    0x4(%esp),%ecx
  401636:   83 e4 f0                and    $0xfffffff0,%esp
  401639:   ff 71 fc                push   -0x4(%ecx)
  40163c:   55                      push   %ebp
  40163d:   89 e5                   mov    %esp,%ebp
  40163f:   51                      push   %ecx
  401640:   83 ec 24                sub    $0x24,%esp
  401643:   e8 38 15 00 00          call   402b80 <_mcount>
  401648:   e8 73 1a 00 00          call   4030c0 <__monstartup>
  40164d:   e8 be 01 00 00          call   401810 <___main>
  401652:   c7 45 f0 00 00 00 00    movl   $0x0,-0x10(%ebp)
  401659:   c7 45 f4 e0 93 04 00    movl   $0x493e0,-0xc(%ebp)
  401660:   8b 45 f0                mov    -0x10(%ebp),%eax
  401663:   39 45 f4                cmp    %eax,-0xc(%ebp)
  401666:   7e 3d                   jle    4016a5 <__fu0___ZSt4cout+0x27>
  401668:   8d 45 f0                lea    -0x10(%ebp),%eax
  40166b:   89 04 24                mov    %eax,(%esp)
  40166e:   e8 5d ff ff ff          call   4015d0 <__Z8is_primeRKi>
  401673:   84 c0                   test   %al,%al
  401675:   74 23                   je     40169a <__fu0___ZSt4cout+0x1c>
  401677:   8b 45 f0                mov    -0x10(%ebp),%eax
  40167a:   89 04 24                mov    %eax,(%esp)
  40167d:   b9                      .byte 0xb9

我可以看到 mcount 在两者的开头都被调用。因此，编译后的代码似乎已正确检测，但 gprof 中仍然没有输出。

Answer 1

这似乎是新版 MinGW 中的一个错误。我之前也遇到过同样的问题。我的 MinGW 是从 winlibs 下载的。当我尝试使用最新版本9.0时，gprof的输出结果确实为空。我尝试了 MinGW 9.0 版和 GCC 11、10 和 9 版，结果都是空的。最后找到了mingw7.0.0-gcc10.2，尝试用这个版本编译，运行然后使用gprof，输出结果不为空，但与Linux平台使用gprof相比，结果有点奇怪