-#include <stdlib.h>
+/** @file threads.cc
+ * @brief Thread functions.
+ */
+
+#include <string.h>
-#include "libthreads.h"
-#include "schedule.h"
+#include <threads.h>
#include "common.h"
-#include "threads.h"
+#include "threads-model.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 userMalloc(size);
+ return snapshot_malloc(size);
}
+/** Free a stack for a terminated thread. */
static void stack_free(void *stack)
{
- userFree(stack);
+ snapshot_free(stack);
}
+/** Return the currently executing thread. */
Thread * thread_current(void)
{
- return model->scheduler->get_current_thread();
+ ASSERT(model);
+ 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
+ */
+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;
context.uc_stack.ss_size = STACK_SIZE;
context.uc_stack.ss_flags = 0;
context.uc_link = model->get_system_context();
- makecontext(&context, start_routine, 1, arg);
+ makecontext(&context, thread_startup, 0);
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)
{
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)
{
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());
+ if (!is_complete()) {
+ DEBUG("completed thread %d\n", id_to_int(get_id()));
state = THREAD_COMPLETED;
if (stack)
stack_free(stack);
}
}
-void * Thread::operator new(size_t size) {
- return userMalloc(size);
-}
-
-void Thread::operator delete(void *ptr) {
- userFree(ptr);
+/**
+ * @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));
}
-Thread::Thread(thrd_t *t, void (*func)(), 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) :
+ creation(NULL),
+ pending(NULL),
+ start_routine(func),
+ arg(a),
+ user_thread(t),
+ state(THREAD_CREATED),
+ wait_list(),
+ last_action_val(VALUE_NONE),
+ model_thread(false)
+{
int ret;
- user_thread = t;
- start_routine = func;
- arg = a;
-
/* Initialize state */
ret = create_context();
if (ret)
- printf("Error in create_context\n");
+ model_print("Error in create_context\n");
- state = THREAD_CREATED;
id = model->get_next_id();
*user_thread = id;
+ parent = thread_current();
}
+/** Destructor */
Thread::~Thread()
{
complete();
model->remove_thread(this);
}
+/** @return The thread_id_t corresponding to this Thread object. */
thread_id_t Thread::get_id()
{
return id;
}
-
-/*
- * Return 1 if found next thread, 0 otherwise
- */
-static int thread_system_next(void)
-{
- Thread *curr, *next;
-
- curr = thread_current();
- if (curr) {
- if (curr->get_state() == THREAD_READY) {
- model->check_current_action();
- model->scheduler->add_thread(curr);
- } else if (curr->get_state() == THREAD_RUNNING)
- /* Stopped while running; i.e., completed */
- curr->complete();
- else
- DEBUG("ERROR: current thread in unexpected state??\n");
- }
- next = model->scheduler->next_thread();
- if (next)
- next->set_state(THREAD_RUNNING);
- DEBUG("(%d, %d)\n", curr ? curr->get_id() : -1, next ? next->get_id() : -1);
- if (!next)
- return 1;
- return Thread::swap(model->get_system_context(), next);
-}
-
-static void thread_wait_finish(void)
-{
-
- DBG();
-
- while (!thread_system_next());
-}
-
-/*
- * Main system function
- */
-int main()
-{
- thrd_t user_thread;
- ucontext_t main_context;
-
- model = new ModelChecker();
-
- if (getcontext(&main_context))
- return 1;
-
- model->set_system_context(&main_context);
-
- do {
- /* Start user program */
- model->add_thread(new Thread(&user_thread, &user_main, NULL));
-
- /* Wait for all threads to complete */
- thread_wait_finish();
- } while (model->next_execution());
-
- delete model;
-
- DEBUG("Exiting\n");
- return 0;
-}
projects / c11tester.git / blobdiff