X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=threads.cc;h=7fa4507ee94397e7e092730567901de94cf07a46;hb=57d7975634e97da2d32f95054dccf40ca871e558;hp=946b5e4f8a312d7a9d8b814d4be7f8785afc3a04;hpb=4dbfd5255074e0924ae22fa37412dbdcea9266c8;p=model-checker.git

diff --git a/threads.cc b/threads.cc
index 946b5e4..7fa4507 100644
--- a/threads.cc
+++ b/threads.cc
@@ -1,30 +1,59 @@
-#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 userMalloc(size);
+	return malloc(size);
 }
 
+/** Free a stack for a terminated thread. */
 static void stack_free(void *stack)
 {
-	userFree(stack);
+	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
+ * @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);
+
+	/* 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;
@@ -39,24 +68,43 @@ int Thread::create_context()
 	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) {
+	if (!is_complete()) {
 		DEBUG("completed thread %d\n", get_id());
 		state = THREAD_COMPLETED;
 		if (stack)
@@ -64,38 +112,40 @@ void Thread::complete()
 	}
 }
 
-void * Thread::operator new(size_t size) {
-	return userMalloc(size);
-}
-
-void Thread::operator delete(void *ptr) {
-	userFree(ptr);
-}
-
-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) :
+	start_routine(func),
+	arg(a),
+	user_thread(t),
+	state(THREAD_CREATED),
+	wait_list(),
+	last_action_val(VALUE_NONE)
+{
 	int ret;
 
-	user_thread = t;
-	start_routine = func;
-	arg = a;
-
 	/* 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();
 }
 
+/** 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;