X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;ds=sidebyside;f=threads.cc;h=f24010697d60f306de512ab40fecdece88875cdd;hb=305c314f6e2e34396053c3974e3be3796a16e4e1;hp=3af74966469afe1a6897802de9e27c434adf4e76;hpb=fe8423ca853f5d614e618fe49d37d0943d416809;p=model-checker.git

diff --git a/threads.cc b/threads.cc
index 3af7496..f240106 100644
--- a/threads.cc
+++ b/threads.cc
@@ -1,30 +1,57 @@
-#include <stdlib.h>
+/** @file threads.cc
+ *  @brief Thread functions.
+ */
 
 #include "libthreads.h"
-#include "schedule.h"
 #include "common.h"
 #include "threads.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);
 }
 
+/** Free a stack for a terminated thread. */
 static void stack_free(void *stack)
 {
 	free(stack);
 }
 
+/** Return the currently executing thread. */
+
 Thread * thread_current(void)
 {
+	ASSERT(model);
 	return model->scheduler->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() {
+	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);
+}
+
+/** Create a thread context for a new thread so we can use
+ *  setcontext/getcontext/swapcontext to swap it out.
+ *  @return 0 on success.
+ */
+
 int Thread::create_context()
 {
 	int ret;
@@ -33,128 +60,74 @@ int Thread::create_context()
 	if (ret)
 		return ret;
 
-	/* start_routine == NULL means this is our initial context */
-	if (!start_routine)
-		return 0;
-
 	/* Initialize new managed context */
 	stack = stack_allocate(STACK_SIZE);
 	context.uc_stack.ss_sp = stack;
 	context.uc_stack.ss_size = STACK_SIZE;
 	context.uc_stack.ss_flags = 0;
-	context.uc_link = &model->system_thread->context;
-	makecontext(&context, start_routine, 1, arg);
+	context.uc_link = model->get_system_context();
+	makecontext(&context, thread_startup, 0);
 
 	return 0;
 }
 
-int Thread::swap(Thread *t)
+int Thread::swap(Thread *t, ucontext_t *ctxt)
 {
-	return swapcontext(&this->context, &t->context);
+	return swapcontext(&t->context, ctxt);
 }
 
-void Thread::dispose()
+int Thread::swap(ucontext_t *ctxt, Thread *t)
 {
-	DEBUG("completed thread %d\n", thread_current()->get_id());
-	state = THREAD_COMPLETED;
-	stack_free(stack);
+	return swapcontext(ctxt, &t->context);
 }
 
-Thread::Thread(thrd_t *t, void (*func)(), void *a) {
-	int ret;
 
-	user_thread = t;
-	start_routine = func;
-	arg = a;
+/** 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);
+	}
+}
+
+/** 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. */
+
+Thread::Thread(thrd_t *t, void (*func)(void *), void *a) :
+	start_routine(func),
+	arg(a),
+	user_thread(t),
+	state(THREAD_CREATED),
+	last_action_val(VALUE_NONE)
+{
+	int ret;
 
 	/* Initialize state */
 	ret = create_context();
 	if (ret)
 		printf("Error in create_context\n");
 
-	state = THREAD_CREATED;
 	id = model->get_next_id();
 	*user_thread = id;
+	parent = thread_current();
 }
 
-Thread::Thread(thrd_t *t) {
-	/* system thread */
-	user_thread = t;
-	start_routine = NULL;
-	arg = NULL;
-
-	state = THREAD_CREATED;
-	id = model->get_next_id();
-	*user_thread = id;
-	create_context();
-	model->add_system_thread(this);
-}
-
-thread_id_t Thread::get_id()
-{
-	return id;
-}
-
-/*
- * Return 1 if found next thread, 0 otherwise
- */
-static int thread_system_next(void)
+Thread::~Thread()
 {
-	Thread *curr, *next;
-
-	curr = thread_current();
-	model->check_current_action();
-	if (curr) {
-		if (curr->get_state() == THREAD_READY)
-			model->scheduler->add_thread(curr);
-		else if (curr->get_state() == THREAD_RUNNING)
-			/* Stopped while running; i.e., completed */
-			curr->dispose();
-		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 model->system_thread->swap(next);
+	complete();
+	model->remove_thread(this);
 }
 
-static void thread_wait_finish(void)
-{
-
-	DBG();
-
-	while (!thread_system_next());
-}
+/** Return the thread_id_t corresponding to this Thread object. */
 
-/*
- * Main system function
- */
-int main()
+thread_id_t Thread::get_id()
 {
-	thrd_t user_thread, main_thread;
-	Thread *th;
-
-	model = new ModelChecker();
-
-	th = new Thread(&main_thread);
-
-	do {
-		/* Start user program */
-		thrd_create(&user_thread, &user_main, NULL);
-
-		/* Wait for all threads to complete */
-		thread_wait_finish();
-
-		model->print_trace();
-	} while (model->next_execution());
-
-	delete th;
-	delete model;
-
-	DEBUG("Exiting\n");
-	return 0;
+	return id;
 }