c++ - 无法让 Helgrind/DRD 使用 C++11 线程

Question

我在让 Helgrind 和 DRD 使用 g++ 和 C++11 线程时遇到问题。

我的设置: - RedHad Linux 2.6 -克++ 4.7.2 - Valgrind 3.7.0

我试过贴出的程序 here ，在添加第一个答案中列出的定义之后，因此:

#include <valgrind/helgrind.h>
#define _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE(addr) ANNOTATE_HAPPENS_BEFORE(addr)
#define _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER(addr) ANNOTATE_HAPPENS_AFTER(addr)
#define _GLIBCXX_EXTERN_TEMPLATE -1

#include <thread>

int main()
{
    std::thread t( []() { } );
    t.join();
    return 0;
}

然后我构建程序:

$ g++ -std=c++11 -Wall -Wextra -pthread main.cc

程序(没有做太多)正确运行:

$ ./a.out

还有 valgrind:

$ valgrind ./a.out
==21284== Memcheck, a memory error detector
==21284== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al.
==21284== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info
==21284== Command: ./a.out
==21284==
==21284==
==21284== HEAP SUMMARY:
==21284==     in use at exit: 0 bytes in 0 blocks
==21284==   total heap usage: 2 allocs, 2 frees, 344 bytes allocated
==21284==
==21284== All heap blocks were freed -- no leaks are possible
==21284==
==21284== For counts of detected and suppressed errors, rerun with: -v
==21284== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 6 from 6)

但是，对于 Helgrind，我得到了误报:

$ valgrind --tool=helgrind ./a.out                                                  
==21467== Helgrind, a thread error detector                                         
==21467== Copyright (C) 2007-2011, and GNU GPL'd, by OpenWorks LLP et al.           
==21467== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info         
==21467== Command: ./a.out                                                          
==21467==                                                                           
==21467== ---Thread-Announcement------------------------------------------          
==21467==                                                                           
==21467== Thread #1 is the program's root thread                                    
==21467==                                                                           
==21467== ---Thread-Announcement------------------------------------------          
==21467== [lines removed]
==21467==                                                                           
==21467== ----------------------------------------------------------------          
==21467==                                                                           
==21467== Possible data race during write of size 8 at 0x5B7A058 by thread #1       
==21467== Locks held: none                                                          
==21467== [lines removed]
==21467==                                                                           
==21467== This conflicts with a previous write of size 8 by thread #2
==21467== Locks held: none
==21467==    at 0x4EE0A25: execute_native_thread_routine (shared_ptr_base.h:587)
==21467==    by 0x4C2D3AD: mythread_wrapper (hg_intercepts.c:219)
==21467==    by 0x55D1850: start_thread (in /lib64/libpthread-2.12.so)
==21467==    by 0x58CF90C: clone (in /lib64/libc-2.12.so)
==21467==
==21467== [lines removed]
==21467==
==21467==
==21467== For counts of detected and suppressed errors, rerun with: -v
==21467== Use --history-level=approx or =none to gain increased speed, at
==21467== the cost of reduced accuracy of conflicting-access information
==21467== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)

使用 DRD 而不是 Helgrind 的类似虚假报告。

知道哪里出了问题吗？

Answer 1

我找到了 this在drd手册中。看来您需要重新编译函数 execute_native_thread_routine() 和 std::thread::_M_start_thread()，并将其与您的程序链接(并且在这些函数的执行时不使用共享库)。

实际上，您的代码可以看到宏 _GLIBCXX_SYNCHRONIZATION_HAPPENS_*，但在构建此库时，它们不会被 c++ 库代码的内部函数看到。这就是为什么您需要使用您用于代码的相同 header 包含和宏定义来重新编译它们。