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2479bb6b9b
been a concept of a 'master thread'. This is the first thread in the process. There was special logic which kept the master thread alive artificially should it attempt to exit before its children. So the master would wait for all children to exit and then exit itself, in the process emitting the final summary of errors, leaks, etc. This has the advantage that any process waiting on this one will see the final summaries appearing before its sys_wait call returns. In other words, the final summary output is synchronous with the master-thread exiting. Unfortunately the master-thread idea has a serious drawback, namely that it can and sometimes does cause threaded programs to deadlock at exit. It introduces an artificial dependency which is that the master thread cannot really exit until all its children have exited. If -- by any means at all -- the children are waiting for the master to exit before exiting themselves, deadlock results. There are now two known examples of such deadlocks. This commit removes the master thread concept and lets threads exit in the order which they would have exited without Valgrind's involvement. The last thread to exit prints the final summaries. This has the disadvantage that final output may appear arbitrarily later relative to the exit of the initial thread. Whether this is a problem in practice remains to be seen. As a minor side effect of this change, some functions have had _NORETURN added to their names. Such functions do not return. The thread in which they execute is guaranteed to exit before they return. This makes the logic somewhat easier to follow. amd64 compilation is now broken. I will fix it shortly. git-svn-id: svn://svn.valgrind.org/valgrind/trunk@3816