promise: associate Promises with a set of threads

[model-checker.git] / promise.cc

diff --git a/promise.cc b/promise.cc
index 259ba058ddba82bbd8eaeb0b8559a24144cd087e..e3b8d65e48d7c542bcf7e27da0473bb012a39057 100644 (file)
--- a/promise.cc
+++ b/promise.cc
@@ -1,21 +1,84 @@
+#define __STDC_FORMAT_MACROS
+#include <inttypes.h>
+
 #include "promise.h"
 #include "model.h"
 #include "schedule.h"
 
-bool Promise::increment_threads(thread_id_t tid) { 
-       unsigned int id=id_to_int(tid); 
-       if (id>=synced_thread.size()) {
-               synced_thread.resize(id+1, false);
+/**
+ * Eliminate a thread which no longer can satisfy this promise. Once all
+ * enabled threads have been eliminated, this promise is unresolvable.
+ *
+ * @param tid The thread ID of the thread to eliminate
+ * @return True, if this elimination has invalidated the promise; false
+ * otherwise
+ */
+bool Promise::eliminate_thread(thread_id_t tid)
+{
+       unsigned int id = id_to_int(tid);
+       if (!thread_is_available(tid))
+               return false;
+
+       available_thread[id] = false;
+       num_available_threads--;
+       return has_failed();
+}
+
+/**
+ * Add a thread which may resolve this promise
+ *
+ * @param tid The thread ID
+ */
+void Promise::add_thread(thread_id_t tid)
+{
+       unsigned int id = id_to_int(tid);
+       if (id >= available_thread.size())
+               available_thread.resize(id + 1, false);
+       if (!available_thread[id]) {
+               available_thread[id] = true;
+               num_available_threads++;
        }
-       if (synced_thread[id])
+}
+
+/**
+ * Check if a thread is available for resolving this promise. That is, the
+ * thread must have been previously marked for resolving this promise, and it
+ * cannot have been eliminated due to synchronization, etc.
+ *
+ * @param tid Thread ID of the thread to check
+ * @return True if the thread is available; false otherwise
+ */
+bool Promise::thread_is_available(thread_id_t tid) const
+{
+       unsigned int id = id_to_int(tid);
+       if (id >= available_thread.size())
                return false;
-       
-       synced_thread[id]=true;
-       bool * enabled=model->get_scheduler()->get_enabled();
+       return available_thread[id];
+}
+
+/** @brief Print debug info about the Promise */
+void Promise::print() const
+{
+       model_print("Promised value %#" PRIx64 ", read from thread %d, available threads to resolve: ", value, read->get_tid());
+       for (unsigned int i = 0; i < available_thread.size(); i++)
+               if (available_thread[i])
+                       model_print("[%d]", i);
+       model_print("\n");
+}
 
-       for(unsigned int i=0;i<model->get_num_threads();i++) {
-               if (!synced_thread[id] && enabled[id])
+/**
+ * Check if this promise has failed. A promise can fail when all threads which
+ * could possibly satisfy the promise have been eliminated.
+ *
+ * @return True, if this promise has failed; false otherwise
+ */
+bool Promise::has_failed() const
+{
+       for (unsigned int i = 0; i < available_thread.size(); i++) {
+               thread_id_t tid = int_to_id(i);
+               if (thread_is_available(tid) && model->is_enabled(tid))
                        return false;
        }
+       ASSERT(num_available_threads == 0);
        return true;
 }