X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=threads.cc;h=cbedbb18bae1d73db1c46a531b4141886875b6be;hp=6a9391f0302467097b415bf4b129eb1b90fffaa5;hb=0997f5bf1b28a79066ed4abfed57f14419ee44d3;hpb=38dbc133c5e2712828cf13e17d05331d2b48dcf2

diff --git a/threads.cc b/threads.cc
index 6a9391f..cbedbb1 100644
--- a/threads.cc
+++ b/threads.cc
@@ -1,26 +1,40 @@
-#include "libthreads.h"
+/** @file threads.cc
+ *  @brief Thread functions.
+ */
+
+#include <string.h>
+
+#include <threads.h>
 #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();
 }
 
 /**
@@ -28,16 +42,25 @@ Thread * thread_current(void)
  * model-checking data to be recorded. This method also gets around makecontext
  * not being 64-bit clean
  */
-void thread_startup() {
+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, memory_order_seq_cst, curr_thread));
+	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;
@@ -57,52 +80,120 @@ 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_thrd) :
+	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;
+	parent = parent_thrd ? parent_thrd : thread_current();
 }
 
+/** Destructor */
 Thread::~Thread()
 {
-	complete();
+	if (!is_complete())
+		complete();
 	model->remove_thread(this);
 }
 
-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;
+}