X-Git-Url: http://plrg.eecs.uci.edu/git/?p=c11tester.git;a=blobdiff_plain;f=threads.cc;h=ae2905a9819a7d4e0159fbbf6d4f439850da1f40;hp=33bb99254e255db59b1045bbf94711535688487a;hb=2b004336a919f74a5ca8f6d87ad5414360a949c7;hpb=08b08df583f48064ec920b56162526f38b1db481 diff --git a/threads.cc b/threads.cc index 33bb9925..ae2905a9 100644 --- a/threads.cc +++ b/threads.cc @@ -2,9 +2,13 @@ * @brief Thread functions. */ -#include "libthreads.h" +#include + +#include +#include #include "common.h" -#include "threads.h" +#include "threads-model.h" +#include "action.h" /* global "model" object */ #include "model.h" @@ -12,32 +16,35 @@ /** Allocate a stack for a new thread. */ static void * stack_allocate(size_t size) { - return malloc(size); + return snapshot_malloc(size); } /** Free a stack for a terminated thread. */ static void stack_free(void *stack) { - free(stack); + snapshot_free(stack); } -/** Return the currently executing thread. */ - +/** + * @brief Get the current Thread + * + * Must be called from a user context + * + * @return The currently executing thread + */ Thread * thread_current(void) { ASSERT(model); - return model->scheduler->get_current_thread(); + return model->get_current_thread(); } /** * Provides a startup wrapper for each thread, allowing some initial * model-checking data to be recorded. This method also gets around makecontext * not being 64-bit clean - * @todo We should make the START event always immediately follow the - * CREATE event, so we don't get redundant traces... */ - -void thread_startup() { +void thread_startup() +{ Thread * curr_thread = thread_current(); /* Add dummy "start" action, just to create a first clock vector */ @@ -45,13 +52,16 @@ void thread_startup() { /* Call the actual thread function */ curr_thread->start_routine(curr_thread->arg); + + /* Finish thread properly */ + model->switch_to_master(new ModelAction(THREAD_FINISH, std::memory_order_seq_cst, curr_thread)); } -/** Create a thread context for a new thread so we can use - * setcontext/getcontext/swapcontext to swap it out. - * @return 0 on success. +/** + * Create a thread context for a new thread so we can use + * setcontext/getcontext/swapcontext to swap it out. + * @return 0 on success; otherwise, non-zero error condition */ - int Thread::create_context() { int ret; @@ -74,75 +84,146 @@ int Thread::create_context() /** * Swaps the current context to another thread of execution. This form switches * from a user Thread to a system context. - * @param t Thread representing the current context - * @param ctxt Context to switch to + * @param t Thread representing the currently-running thread. The current + * context is saved here. + * @param ctxt Context to which we will swap. Must hold a valid system context. * @return Does not return, unless we return to Thread t's context. See * swapcontext(3) (returns 0 for success, -1 for failure). */ int Thread::swap(Thread *t, ucontext_t *ctxt) { - return swapcontext(&t->context, ctxt); + t->set_state(THREAD_READY); + return model_swapcontext(&t->context, ctxt); } /** * Swaps the current context to another thread of execution. This form switches * from a system context to a user Thread. - * @param t Thread representing the current context - * @param ctxt Context to switch to - * @return Does not return, unless we return to Thread t's context. See + * @param ctxt System context variable to which to save the current context. + * @param t Thread to which we will swap. Must hold a valid user context. + * @return Does not return, unless we return to the system context (ctxt). See * swapcontext(3) (returns 0 for success, -1 for failure). */ int Thread::swap(ucontext_t *ctxt, Thread *t) { - return swapcontext(ctxt, &t->context); + t->set_state(THREAD_RUNNING); + return model_swapcontext(ctxt, &t->context); } /** Terminate a thread and free its stack. */ void Thread::complete() { - if (state != THREAD_COMPLETED) { - DEBUG("completed thread %d\n", get_id()); - state = THREAD_COMPLETED; - if (stack) - stack_free(stack); - } + ASSERT(!is_complete()); + DEBUG("completed thread %d\n", id_to_int(get_id())); + state = THREAD_COMPLETED; + if (stack) + stack_free(stack); } -/** Create a new thread. - * Takes the following parameters: - * @param t The thread identifier of the newly created thread. - * @param func The function that the thread will call. - * @param a The parameter to pass to this function. */ +/** + * @brief Construct a new model-checker Thread + * + * A model-checker Thread is used for accounting purposes only. It will never + * have its own stack, and it should never be inserted into the Scheduler. + * + * @param tid The thread ID to assign + */ +Thread::Thread(thread_id_t tid) : + parent(NULL), + creation(NULL), + pending(NULL), + start_routine(NULL), + arg(NULL), + stack(NULL), + user_thread(NULL), + id(tid), + state(THREAD_READY), /* Thread is always ready? */ + last_action_val(0), + model_thread(true) +{ + memset(&context, 0, sizeof(context)); +} -Thread::Thread(thrd_t *t, void (*func)(void *), void *a) : +/** + * Construct a new thread. + * @param t The thread identifier of the newly created thread. + * @param func The function that the thread will call. + * @param a The parameter to pass to this function. + */ +Thread::Thread(thrd_t *t, void (*func)(void *), void *a, Thread *parent) : + parent(parent), + creation(NULL), + pending(NULL), start_routine(func), arg(a), user_thread(t), state(THREAD_CREATED), - last_action_val(VALUE_NONE) + last_action_val(VALUE_NONE), + model_thread(false) { int ret; /* Initialize state */ ret = create_context(); if (ret) - printf("Error in create_context\n"); + model_print("Error in create_context\n"); id = model->get_next_id(); - *user_thread = id; - parent = thread_current(); + user_thread->priv = this; } +/** Destructor */ Thread::~Thread() { - complete(); - model->remove_thread(this); + if (!is_complete()) + complete(); } -/** Return the thread_id_t corresponding to this Thread object. */ - -thread_id_t Thread::get_id() +/** @return The thread_id_t corresponding to this Thread object. */ +thread_id_t Thread::get_id() const { return id; } + +/** + * Set a thread's THREAD_* state (@see thread_state) + * @param s The state to enter + */ +void Thread::set_state(thread_state s) +{ + ASSERT(s == THREAD_COMPLETED || state != THREAD_COMPLETED); + state = s; +} + +/** + * Get the Thread that this Thread is immediately waiting on + * @return The thread we are waiting on, if any; otherwise NULL + */ +Thread * Thread::waiting_on() const +{ + if (!pending) + return NULL; + + if (pending->get_type() == THREAD_JOIN) + return pending->get_thread_operand(); + else if (pending->is_lock()) + return (Thread *)pending->get_mutex()->get_state()->locked; + return NULL; +} + +/** + * Check if this Thread is waiting (blocking) on a given Thread, directly or + * indirectly (via a chain of waiting threads) + * + * @param t The Thread on which we may be waiting + * @return True if we are waiting on Thread t; false otherwise + */ +bool Thread::is_waiting_on(const Thread *t) const +{ + Thread *wait; + for (wait = waiting_on(); wait != NULL; wait = wait->waiting_on()) + if (wait == t) + return true; + return false; +}