changes
[model-checker.git] / datarace.cc
index 832a220a3148796940cf2c84ba154bca5932fd9b..5856e770b326eece6dee601dbf346e32b140ed07 100644 (file)
@@ -21,16 +21,31 @@ static uint64_t * lookupAddressEntry(void * address) {
        struct ShadowBaseTable * basetable=(struct ShadowBaseTable *) currtable->array[(((uintptr_t)address)>>16)&MASK16BIT];
        if (basetable==NULL) {
                basetable=(struct ShadowBaseTable *) (currtable->array[(((uintptr_t)address)>>16)&MASK16BIT]=calloc(sizeof(struct ShadowBaseTable),1));
-       }       
+       }
        return &basetable->array[((uintptr_t)address)&MASK16BIT];
 }
 
+/**
+ * Compares a current clock-vector/thread-ID pair with a clock/thread-ID pair
+ * to check the potential for a data race.
+ * @param clock1 The current clock vector
+ * @param tid1 The current thread; paired with clock1
+ * @param clock2 The clock value for the potentially-racing action
+ * @param tid2 The thread ID for the potentially-racing action
+ * @return true if the current clock allows a race with the event at clock2/tid2
+ */
+static bool clock_may_race(ClockVector *clock1, thread_id_t tid1,
+                           modelclock_t clock2, thread_id_t tid2)
+{
+       return tid1 != tid2 && clock2 != 0 && clock1->getClock(tid2) <= clock2;
+}
+
 static void expandRecord(uint64_t * shadow) {
        uint64_t shadowval=*shadow;
 
-       int readClock = READVECTOR(shadowval);
+       modelclock_t readClock = READVECTOR(shadowval);
        thread_id_t readThread = int_to_id(RDTHREADID(shadowval));
-       int writeClock = WRITEVECTOR(shadowval);
+       modelclock_t writeClock = WRITEVECTOR(shadowval);
        thread_id_t writeThread = int_to_id(WRTHREADID(shadowval));
 
        struct RaceRecord * record=(struct RaceRecord *)calloc(1,sizeof(struct RaceRecord));
@@ -40,7 +55,7 @@ static void expandRecord(uint64_t * shadow) {
        if (readClock!=0) {
                record->capacity=INITCAPACITY;
                record->thread=(thread_id_t *) malloc(sizeof(thread_id_t)*record->capacity);
-               record->readClock=(int *) malloc(sizeof(int)*record->capacity);
+               record->readClock=(modelclock_t *) malloc(sizeof(modelclock_t)*record->capacity);
                record->numReads=1;
                record->thread[0]=readThread;
                record->readClock[0]=readClock;
@@ -58,28 +73,31 @@ void fullRaceCheckWrite(thread_id_t thread, uint64_t * shadow, ClockVector *curr
        /* Check for datarace against last read. */
 
        for(int i=0;i<record->numReads;i++) {
-               int readClock = record->readClock[i];
+               modelclock_t readClock = record->readClock[i];
                thread_id_t readThread = record->thread[i];
-               
-               if (readThread != thread && readClock != 0 && currClock->getClock(readThread) <= readClock) {
+
+               /* Note that readClock can't actuall be zero here, so it could be
+                        optimized. */
+
+               if (clock_may_race(currClock, thread, readClock, readThread)) {
                        /* We have a datarace */
                        reportDataRace();
                }
        }
-       
+
        /* Check for datarace against last write. */
-       
-       int writeClock = record->writeClock;
+
+       modelclock_t writeClock = record->writeClock;
        thread_id_t writeThread = record->writeThread;
-       
-       if (writeThread != thread && writeClock != 0 && currClock->getClock(writeThread) <= writeClock) {
+
+       if (clock_may_race(currClock, thread, writeClock, writeThread)) {
                /* We have a datarace */
                reportDataRace();
        }
-       
+
        record->numReads=0;
        record->writeThread=thread;
-       int ourClock = currClock->getClock(thread);
+       modelclock_t ourClock = currClock->getClock(thread);
        record->writeClock=ourClock;
 }
 
@@ -94,31 +112,31 @@ void raceCheckWrite(thread_id_t thread, void *location, ClockVector *currClock)
        }
 
        int threadid = id_to_int(thread);
-       int ourClock = currClock->getClock(thread);
-       
+       modelclock_t ourClock = currClock->getClock(thread);
+
        /* Thread ID is too large or clock is too large. */
        if (threadid > MAXTHREADID || ourClock > MAXWRITEVECTOR) {
                expandRecord(shadow);
                fullRaceCheckWrite(thread, shadow, currClock);
                return;
        }
-       
+
        /* Check for datarace against last read. */
 
-       int readClock = READVECTOR(shadowval);
+       modelclock_t readClock = READVECTOR(shadowval);
        thread_id_t readThread = int_to_id(RDTHREADID(shadowval));
 
-       if (readThread != thread && readClock != 0 && currClock->getClock(readThread) <= readClock) {
+       if (clock_may_race(currClock, thread, readClock, readThread)) {
                /* We have a datarace */
                reportDataRace();
        }
 
        /* Check for datarace against last write. */
 
-       int writeClock = WRITEVECTOR(shadowval);
+       modelclock_t writeClock = WRITEVECTOR(shadowval);
        thread_id_t writeThread = int_to_id(WRTHREADID(shadowval));
-       
-       if (writeThread != thread && writeClock != 0 && currClock->getClock(writeThread) <= writeClock) {
+
+       if (clock_may_race(currClock, thread, writeClock, writeThread)) {
                /* We have a datarace */
                reportDataRace();
        }
@@ -129,11 +147,11 @@ void fullRaceCheckRead(thread_id_t thread, uint64_t * shadow, ClockVector *currC
        struct RaceRecord * record=(struct RaceRecord *) (*shadow);
 
        /* Check for datarace against last write. */
-       
-       int writeClock = record->writeClock;
+
+       modelclock_t writeClock = record->writeClock;
        thread_id_t writeThread = record->writeThread;
-       
-       if (writeThread != thread && writeClock != 0 && currClock->getClock(writeThread) <= writeClock) {
+
+       if (clock_may_race(currClock, thread, writeClock, writeThread)) {
                /* We have a datarace */
                reportDataRace();
        }
@@ -143,10 +161,16 @@ void fullRaceCheckRead(thread_id_t thread, uint64_t * shadow, ClockVector *currC
        int copytoindex=0;
 
        for(int i=0;i<record->numReads;i++) {
-               int readClock = record->readClock[i];
+               modelclock_t readClock = record->readClock[i];
                thread_id_t readThread = record->thread[i];
-               
-               if (readThread != thread && currClock->getClock(readThread) <= readClock) {
+
+               /*  Note that is not really a datarace check as reads cannott
+                               actually race.  It is just determining that this read subsumes
+                               another in the sense that either this read races or neither
+                               read races. Note that readClock can't actually be zero, so it
+                               could be optimized.  */
+
+               if (clock_may_race(currClock, thread, readClock, readThread) {
                        /* Still need this read in vector */
                        if (copytoindex!=i) {
                                record->readClock[copytoindex]=record->readClock[i];
@@ -155,13 +179,13 @@ void fullRaceCheckRead(thread_id_t thread, uint64_t * shadow, ClockVector *currC
                        copytoindex++;
                }
        }
-       
+
        if (copytoindex>=record->capacity) {
                int newCapacity=record->capacity*2;
                thread_id_t *newthread=(thread_id_t *) malloc(sizeof(thread_id_t)*newCapacity);
-               int * newreadClock=(int *) malloc(sizeof(int)*newCapacity);             
+               modelclock_t * newreadClock=(modelclock_t *) malloc(sizeof(modelclock_t)*newCapacity);
                std::memcpy(newthread, record->thread, record->capacity*sizeof(thread_id_t));
-               std::memcpy(newreadClock, record->readClock, record->capacity*sizeof(int));
+               std::memcpy(newreadClock, record->readClock, record->capacity*sizeof(modelclock_t));
                free(record->readClock);
                free(record->thread);
                record->readClock=newreadClock;
@@ -169,8 +193,8 @@ void fullRaceCheckRead(thread_id_t thread, uint64_t * shadow, ClockVector *currC
                record->capacity=newCapacity;
        }
 
-       int ourClock = currClock->getClock(thread);
-       
+       modelclock_t ourClock = currClock->getClock(thread);
+
        record->thread[copytoindex]=thread;
        record->readClock[copytoindex]=ourClock;
        record->numReads=copytoindex+1;
@@ -187,8 +211,8 @@ void raceCheckRead(thread_id_t thread, void *location, ClockVector *currClock) {
        }
 
        int threadid = id_to_int(thread);
-       int ourClock = currClock->getClock(thread);
-       
+       modelclock_t ourClock = currClock->getClock(thread);
+
        /* Thread ID is too large or clock is too large. */
        if (threadid > MAXTHREADID || ourClock > MAXWRITEVECTOR) {
                expandRecord(shadow);
@@ -198,23 +222,23 @@ void raceCheckRead(thread_id_t thread, void *location, ClockVector *currClock) {
 
        /* Check for datarace against last write. */
 
-       int writeClock = WRITEVECTOR(shadowval);
+       modelclock_t writeClock = WRITEVECTOR(shadowval);
        thread_id_t writeThread = int_to_id(WRTHREADID(shadowval));
-       
-       if (writeThread != thread && writeClock != 0 && currClock->getClock(writeThread) <= writeClock) {
+
+       if (clock_may_race(currClock, thread, writeClock, writeThread)) {
                /* We have a datarace */
                reportDataRace();
        }
-       
-       int readClock = READVECTOR(shadowval);
+
+       modelclock_t readClock = READVECTOR(shadowval);
        thread_id_t readThread = int_to_id(RDTHREADID(shadowval));
 
-       if (readThread != thread && readClock != 0 && currClock->getClock(readThread) <= readClock) {
+       if (clock_may_race(currClock, thread, readClock, readThread)) {
                /* We don't subsume this read... Have to expand record. */
                expandRecord(shadow);
                fullRaceCheckRead(thread, shadow, currClock);
                return;
        }
-               
+
        *shadow = ENCODEOP(writeThread, writeClock, threadid, ourClock);
 }