From: Brian Demsky <bdemsky@uci.edu>
Date: Wed, 25 Jul 2012 23:11:51 +0000 (-0700)
Subject: some changes towards reading from future writes
X-Git-Tag: pldi2013~309
X-Git-Url: http://demsky.eecs.uci.edu/git/?p=model-checker.git;a=commitdiff_plain;h=bdef0741b8a01e16946d261bc2a657af5a683b3e

some changes towards reading from future writes
---

diff --git a/Makefile b/Makefile
index 2d31611..4526ed7 100644
--- a/Makefile
+++ b/Makefile
@@ -8,9 +8,9 @@ LIB_SO=lib$(LIB_NAME).so
 USER_O=userprog.o
 USER_H=libthreads.h
 
-MODEL_CC=libthreads.cc schedule.cc model.cc threads.cc librace.cc action.cc nodestack.cc clockvector.cc main.cc snapshot-interface.cc cyclegraph.cc datarace.cc impatomic.cc cmodelint.cc
-MODEL_O=libthreads.o schedule.o model.o threads.o librace.o action.o nodestack.o clockvector.o main.o snapshot-interface.o cyclegraph.o datarace.o impatomic.o cmodelint.o
-MODEL_H=libthreads.h schedule.h common.h model.h threads.h librace.h action.h nodestack.h clockvector.h snapshot-interface.h cyclegraph.h hashtable.h datarace.h config.h include/impatomic.h include/cstdatomic include/stdatomic.h cmodelint.h
+MODEL_CC=libthreads.cc schedule.cc model.cc threads.cc librace.cc action.cc nodestack.cc clockvector.cc main.cc snapshot-interface.cc cyclegraph.cc datarace.cc impatomic.cc cmodelint.cc promise.cc
+MODEL_O=libthreads.o schedule.o model.o threads.o librace.o action.o nodestack.o clockvector.o main.o snapshot-interface.o cyclegraph.o datarace.o impatomic.o cmodelint.o promise.o
+MODEL_H=libthreads.h schedule.h common.h model.h threads.h librace.h action.h nodestack.h clockvector.h snapshot-interface.h cyclegraph.h hashtable.h datarace.h config.h include/impatomic.h include/cstdatomic include/stdatomic.h cmodelint.h promise.h
 
 SHMEM_CC=snapshot.cc malloc.c mymemory.cc
 SHMEM_O=snapshot.o malloc.o mymemory.o
diff --git a/model.cc b/model.cc
index a9d76c6..bfa3e02 100644
--- a/model.cc
+++ b/model.cc
@@ -8,6 +8,7 @@
 #include "common.h"
 #include "clockvector.h"
 #include "cyclegraph.h"
+#include "promise.h"
 
 #define INITIAL_THREAD_ID	0
 
@@ -30,6 +31,7 @@ ModelChecker::ModelChecker()
 	thread_map(new HashTable<int, Thread *, int>()),
 	obj_map(new HashTable<const void *, action_list_t, uintptr_t, 4>()),
 	obj_thrd_map(new HashTable<void *, std::vector<action_list_t>, uintptr_t, 4 >()),
+	promises(new std::vector<Promise *>(1)),
 	thrd_last_action(new std::vector<ModelAction *>(1)),
 	node_stack(new NodeStack()),
 	next_backtrack(NULL),
diff --git a/model.h b/model.h
index b6099c6..41ec97b 100644
--- a/model.h
+++ b/model.h
@@ -16,10 +16,12 @@
 #include "threads.h"
 #include "action.h"
 #include "clockvector.h"
+#include "hashtable.h"
 
 /* Forward declaration */
 class NodeStack;
 class CycleGraph;
+class Promise;
 
 /** @brief The central structure for model-checking */
 class ModelChecker {
@@ -99,6 +101,7 @@ private:
 	HashTable<const void *, action_list_t, uintptr_t, 4> *obj_map;
 
 	HashTable<void *, std::vector<action_list_t>, uintptr_t, 4 > *obj_thrd_map;
+	std::vector<Promise *> * promises;
 	std::vector<ModelAction *> *thrd_last_action;
 	NodeStack *node_stack;
 	ModelAction *next_backtrack;
diff --git a/nodestack.cc b/nodestack.cc
index 409c4e1..6295442 100644
--- a/nodestack.cc
+++ b/nodestack.cc
@@ -25,7 +25,9 @@ Node::Node(ModelAction *act, Node *par, int nthreads)
 	backtrack(num_threads),
 	numBacktracks(0),
 	may_read_from(),
-	read_from_index(0)
+	read_from_index(0),
+	future_values(),
+	future_index(0)
 {
 	if (act)
 		act->set_node(this);
@@ -55,6 +57,19 @@ void Node::print_may_read_from()
 		(*it)->print();
 }
 
+/**
+ * Adds a value from a weakly ordered future write to backtrack to.
+ * @param value is the value to backtrack to.
+ */
+
+void Node::add_future_value(uint64_t value) {
+	for(int i=0;i<future_values.size();i++)
+		if (future_values[i]==value)
+			return;
+	future_values.push_back(value);
+}
+
+
 /**
  * Checks if the Thread associated with this thread ID has been explored from
  * this Node already.
@@ -86,8 +101,17 @@ bool Node::readsfrom_empty() {
 	return ((read_from_index+1)>=may_read_from.size());
 }
 
+/** 
+ * Checks whether the future_values set for this node is empty.
+ * @return true if the future_values set is empty.
+ */
+
+bool Node::futurevalues_empty() {
+	return ((future_index+1)>=future_values.size());
+}
+
 /**
- * Mark the appropriate backtracking infromation for exploring a thread choice.
+ * Mark the appropriate backtracking information for exploring a thread choice.
  * @param act The ModelAction to explore
  */
 void Node::explore_child(ModelAction *act)
@@ -141,6 +165,17 @@ void Node::add_read_from(const ModelAction *act)
 	may_read_from.push_back(act);
 }
 
+/**
+ * Gets the next 'future_value' value from this Node. Only valid for a node
+ * where this->action is a 'read'.
+ * @return The first element in future_values
+ */
+
+uint64_t Node::get_future_value() {
+	ASSERT(future_index<future_values.size());
+	return future_values[future_index];
+}
+
 /**
  * Gets the next 'may_read_from' action from this Node. Only valid for a node
  * where this->action is a 'read'.
@@ -162,6 +197,16 @@ bool Node::increment_read_from() {
 	return (read_from_index<may_read_from.size());
 }
 
+/**
+ * Increments the index into the future_values set to explore the next item.
+ * @return Returns false if we have explored all values.
+ */
+
+bool Node::increment_future_values() {
+	future_index++;
+	return (future_index<future_values.size());
+}
+
 void Node::explore(thread_id_t tid)
 {
 	int i = id_to_int(tid);
diff --git a/nodestack.h b/nodestack.h
index 6f7807f..16264a2 100644
--- a/nodestack.h
+++ b/nodestack.h
@@ -14,6 +14,7 @@
 class ModelAction;
 
 typedef std::vector< const ModelAction *, MyAlloc< const ModelAction * > > readfrom_set_t;
+typedef std::vector< uint64_t, MyAlloc< uint64_t > > futurevalues_t;
 
 /**
  * @brief A single node in a NodeStack
@@ -33,6 +34,7 @@ public:
 	/* return true = backtrack set is empty */
 	bool backtrack_empty();
 	bool readsfrom_empty();
+	bool futurevalues_empty();
 	void explore_child(ModelAction *act);
 	/* return false = thread was already in backtrack */
 	bool set_backtrack(thread_id_t id);
@@ -44,9 +46,12 @@ public:
 	 * occurred previously in the stack. */
 	Node * get_parent() const { return parent; }
 
+	void add_future_value(uint64_t value);
 	void add_read_from(const ModelAction *act);
 	const ModelAction * get_read_from();
+	uint64_t get_future_value();
 	bool increment_read_from();
+	bool increment_future_values();
 
 	void print();
 	void print_may_read_from();
@@ -66,6 +71,9 @@ private:
 	 *  from. Only meaningful if this Node represents a 'read' action. */
 	readfrom_set_t may_read_from;
 	unsigned int read_from_index;
+
+	futurevalues_t future_values;
+	unsigned int future_index;
 };
 
 typedef std::list< Node *, MyAlloc< Node * > > node_list_t;
diff --git a/promise.cc b/promise.cc
new file mode 100644
index 0000000..b051ef0
--- /dev/null
+++ b/promise.cc
@@ -0,0 +1,8 @@
+#include "promise.h"
+
+Promise::Promise(ModelAction *act, uint64_t value) {
+	this->value=value;
+	this->read=act;
+	this->numthreads=1;
+}
+
diff --git a/promise.h b/promise.h
new file mode 100644
index 0000000..a47982d
--- /dev/null
+++ b/promise.h
@@ -0,0 +1,23 @@
+/** @file promise.h
+ *
+ *  @brief Promise class --- tracks future obligations for execution
+ *  related to weakly ordered writes.
+ */
+
+#ifndef __PROMISE_H__
+#define __PROMISE_H__
+#include <inttypes.h>
+
+
+class ModelAction;
+
+class Promise {
+ public:
+	Promise(ModelAction * act, uint64_t value);
+ private:
+	uint64_t value;
+	ModelAction *read;
+	unsigned int numthreads;
+};
+
+#endif