<html>
    <head>
      <base href="http://llvm.org/bugs/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - compiled code crash in std::string destructor in lambda capture on PPC 32"
   href="http://llvm.org/bugs/show_bug.cgi?id=20826">20826</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>compiled code crash in std::string destructor in lambda capture on PPC 32
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>clang
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>trunk
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Other
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>normal
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>C++11
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>bayoubengal@mac.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>I'm cross-compiling. host == OSX 10.9. target == -target powerpc-unknown-linux
-m32 -mcpu=e500v2 -std=c++14. clang code version == 'clang version 3.6.0 (trunk
216704)' std lib flag == '-stdlib=libc++'.  optimization flags == '-g -O0'

The code crashes in the basic_string destructor with the system complaining of
a double free of a pointer. I do indeed see this pointer being passed to free()
multiple times. However, I have no discerned if the pointer is being
reallocated each time.

message from system == '*** glibc detected *** /test/testPocosn_static: double
free or corruption (fasttop): 0x100940e0 ***
======= Backtrace: ========='


partial backtrace of the crash...

#4  0x1000673c in deallocate (this=0x8214924e, __p=0x4 <error: Cannot access
memory at address 0x4>)
    at
/Volumes/dev/devel/testPoco/../PrgSDK_1/comx_p2020/supernode_3/linuxSDK3.8/usr/include/c++/v1/memory:1636
#5  deallocate (__a=..., __p=0x0, __n=0) at
/Volumes/dev/devel/testPoco/../PrgSDK_1/comx_p2020/supernode_3/linuxSDK3.8/usr/include/c++/v1/memory:1447
#6  std::__1::basic_string<char, std::__1::char_traits<char>,
std::__1::allocator<char> >::~basic_string (this=0x0)
    at
/Volumes/dev/devel/testPoco/../PrgSDK_1/comx_p2020/supernode_3/linuxSDK3.8/usr/include/c++/v1/string:2244
#7  0x8256c9a2 in ?? ()





code snippet:


(This code runs fine when targeting OSX 10.9/x86_64)


#include <string>
#include <memory>
#include <iostream>
#include <future>


int main(int argc, char** argv)
{

   std::string tmpCaptureTest="test a captured string";




   auto tmpCallback = [=](const std::string& s, int i , double d)
   {

      std::cout << tmpCaptureTest << s << i << d << std::endl;



      return 43;
   };

   std::packaged_task<int (const std::string& s, int i , double d)>
tmpTask(tmpCallback);

   std::future<int> tmpTaskResult = tmpTask.get_future();






   auto tmpArg1 = "test";
   auto tmpArg2 = 56;
   auto tmpArg3 = 3.7;
   auto tmpDispatchCallbackWrapper = [=, tmpTask2 = std::move(tmpTask)] ()
mutable
   {


      tmpTask2(tmpArg1, tmpArg2, tmpArg3);

   };

   return 0;
}</pre>
        </div>
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