execution: bugfix - resolved promises should propagate synchronization

[cdsspec-compiler.git] / threads.cc

diff --git a/threads.cc b/threads.cc
index 9b7954d9386b6f5390ed42a32b43a53f5f5f1ca7..a0bc02970aa9ff71c6e8e1a04f6565d52b6db43a 100644 (file)
--- a/threads.cc
+++ b/threads.cc
@@ -2,9 +2,13 @@
  *  @brief Thread functions.
  */
 
-#include "libthreads.h"
+#include <string.h>
+
+#include <threads.h>
+#include <mutex>
 #include "common.h"
-#include "threads.h"
+#include "threads-model.h"
+#include "action.h"
 
 /* global "model" object */
 #include "model.h"
@@ -12,16 +16,22 @@
 /** 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);
 }
 
-/** Return the currently executing thread. */
+/**
+ * @brief Get the current Thread
+ *
+ * Must be called from a user context
+ *
+ * @return The currently executing thread
+ */
 Thread * thread_current(void)
 {
        ASSERT(model);
@@ -32,8 +42,6 @@ Thread * thread_current(void)
  * 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()
 {
@@ -44,6 +52,9 @@ void thread_startup()
 
        /* 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));
 }
 
 /**
@@ -81,7 +92,8 @@ int Thread::create_context()
  */
 int Thread::swap(Thread *t, ucontext_t *ctxt)
 {
-       return swapcontext(&t->context, ctxt);
+       t->set_state(THREAD_READY);
+       return model_swapcontext(&t->context, ctxt);
 }
 
 /**
@@ -94,19 +106,43 @@ int Thread::swap(Thread *t, ucontext_t *ctxt)
  */
 int Thread::swap(ucontext_t *ctxt, Thread *t)
 {
-       return swapcontext(ctxt, &t->context);
+       t->set_state(THREAD_RUNNING);
+       return model_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);
+}
+
+/**
+ * @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? */
+       last_action_val(0),
+       model_thread(true)
+{
+       memset(&context, 0, sizeof(context));
 }
 
 /**
@@ -115,34 +151,79 @@ void Thread::complete()
  * @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::Thread(thread_id_t tid, thrd_t *t, void (*func)(void *), void *a, Thread *parent) :
+       parent(parent),
+       creation(NULL),
+       pending(NULL),
        start_routine(func),
        arg(a),
        user_thread(t),
+       id(tid),
        state(THREAD_CREATED),
-       last_action_val(VALUE_NONE)
+       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();
 }
 
 /** @return The thread_id_t corresponding to this Thread object. */
-thread_id_t Thread::get_id()
+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 immediately 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;
+}
+
+/**
+ * Check if this Thread is waiting (blocking) on a given Thread, directly or
+ * indirectly (via a chain of waiting threads)
+ *
+ * @param t The Thread on which we may be waiting
+ * @return True if we are waiting on Thread t; false otherwise
+ */
+bool Thread::is_waiting_on(const Thread *t) const
+{
+       Thread *wait;
+       for (wait = waiting_on(); wait != NULL; wait = wait->waiting_on())
+               if (wait == t)
+                       return true;
+       return false;
+}