struct ShadowTable *root;
+/** This function initialized the data race detector. */
void initRaceDetector() {
root=(struct ShadowTable *) calloc(sizeof(struct ShadowTable),1);
}
+/** This function looks up the entry in the shadow table corresponding to a
+ * given address.*/
static uint64_t * lookupAddressEntry(void * address) {
struct ShadowTable *currtable=root;
-#ifdef BIT48
- currtable=(struct ShadowTable *) currtable->array[(((uintptr_t)address)>>32)&0xffff];
+#if BIT48
+ currtable=(struct ShadowTable *) currtable->array[(((uintptr_t)address)>>32)&MASK16BIT];
if (currtable==NULL) {
currtable=(struct ShadowTable *) (root->array[(((uintptr_t)address)>>32)&MASK16BIT]=calloc(sizeof(struct ShadowTable),1));
}
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;
+}
+
+/**
+ * Expands a record from the compact form to the full form. This is
+ * necessary for multiple readers or for very large thread ids or time
+ * stamps. */
static void expandRecord(uint64_t * shadow) {
uint64_t shadowval=*shadow;
*shadow=(uint64_t) record;
}
+/** This function is called when we detect a data race.*/
static void reportDataRace() {
printf("The reportDataRace method should report useful things about this datarace!\n");
}
+/** This function does race detection for a write on an expanded record. */
void fullRaceCheckWrite(thread_id_t thread, uint64_t * shadow, ClockVector *currClock) {
struct RaceRecord * record=(struct RaceRecord *) (*shadow);
for(int i=0;i<record->numReads;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. */
-
+
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;
modelclock_t ourClock = currClock->getClock(thread);
record->writeClock=ourClock;
}
+/** This function does race detection on a write. */
void raceCheckWrite(thread_id_t thread, void *location, ClockVector *currClock) {
uint64_t * shadow=lookupAddressEntry(location);
uint64_t shadowval=*shadow;
int threadid = id_to_int(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. */
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();
}
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();
}
*shadow = ENCODEOP(0, 0, threadid, ourClock);
}
+/** This function does race detection on a read for an expanded record. */
void fullRaceCheckRead(thread_id_t thread, uint64_t * shadow, ClockVector *currClock) {
struct RaceRecord * record=(struct RaceRecord *) (*shadow);
/* Check for datarace against last write. */
-
+
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();
}
for(int i=0;i<record->numReads;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];
copytoindex++;
}
}
-
+
if (copytoindex>=record->capacity) {
int newCapacity=record->capacity*2;
thread_id_t *newthread=(thread_id_t *) malloc(sizeof(thread_id_t)*newCapacity);
}
modelclock_t ourClock = currClock->getClock(thread);
-
+
record->thread[copytoindex]=thread;
record->readClock[copytoindex]=ourClock;
record->numReads=copytoindex+1;
}
+/** This function does race detection on a read. */
void raceCheckRead(thread_id_t thread, void *location, ClockVector *currClock) {
uint64_t * shadow=lookupAddressEntry(location);
uint64_t shadowval=*shadow;
int threadid = id_to_int(thread);
modelclock_t ourClock = currClock->getClock(thread);
-
+
/* Thread ID is too large or clock is too large. */
if (threadid > MAXTHREADID || ourClock > MAXWRITEVECTOR) {
expandRecord(shadow);
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();
}
-
+
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);
}
projects / model-checker.git / blobdiff