X-Git-Url: http://plrg.eecs.uci.edu/git/?p=c11tester.git;a=blobdiff_plain;f=threads.cc;h=00e5c2fbd4a0f1287ac6b68b8be50a1a49b82bd8;hp=ba7b54730781369fd6c17ec9f4bc492d660b3843;hb=a575b5d5d2f0edab95e7e0ef8ca6e40b68e0bad9;hpb=1069e1b27fc4ed06476da0a8793a55e68b8a6b86 diff --git a/threads.cc b/threads.cc index ba7b5473..00e5c2fb 100644 --- a/threads.cc +++ b/threads.cc @@ -1,35 +1,67 @@ -#include "libthreads.h" +/** @file threads.cc + * @brief Thread functions. + */ + +#include + +#include +#include #include "common.h" -#include "threads.h" +#include "threads-model.h" +#include "action.h" /* global "model" object */ #include "model.h" -#define STACK_SIZE (1024 * 1024) - +/** 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); } +/** + * @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(); } -/* This method just gets around makecontext not being 64-bit clean */ - -void thread_startup() { +/** + * 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 + */ +void thread_startup() +{ Thread * curr_thread = thread_current(); + + /* Add dummy "start" action, just to create a first clock vector */ + model->switch_to_master(new ModelAction(THREAD_START, std::memory_order_seq_cst, curr_thread)); + + /* 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; otherwise, non-zero error condition + */ int Thread::create_context() { int ret; @@ -49,52 +81,135 @@ int Thread::create_context() return 0; } +/** + * 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 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) { + t->set_state(THREAD_READY); return 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 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) { + t->set_state(THREAD_RUNNING); return 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); } -Thread::Thread(thrd_t *t, void (*func)(void *), void *a) : +/** + * @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? */ + wait_list(), + last_action_val(0), + model_thread(true) +{ + memset(&context, 0, sizeof(context)); +} + +/** + * 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) + wait_list(), + 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(); } -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 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; +}