some changes towards reading from future writes

diff --git a/Makefile b/Makefile
index 2d3161179c45a4a650402140ffaa6bfdf32d9e43..4526ed7fc65498bc612c6bd962491de9a9ada448 100644 (file)
--- 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 a9d76c66a1e86b746d22da4b7505966355ffb660..bfa3e02997ee42ed860fcf872d297906a6ac38b5 100644 (file)
--- 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 b6099c69750b066d74d1d4a566834237edf3b097..41ec97b50bdb71744075d0216a4bb209813255a9 100644 (file)
--- 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 409c4e1e52ba431b729ec4b1c6d95168cfbc675b..6295442606612f0feff684f3657756b167239628 100644 (file)
--- 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 6f7807f66f97626cb96b816bd9c7c86fd4d07dbe..16264a2bbf800c6832e312cab644e85febb4f566 100644 (file)
--- 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 (file)
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 (file)
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