X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=datarace.cc;h=f0d3dc619489d780ea7e9be237b2007d428a4b33;hb=84e24d516d4e9dbd30f1fff7e9a185d1540d20eb;hp=1040a3b0df2d4871f21515e62d2d94e5a6651313;hpb=1555554a743a69644432215413e0dad83a18a235;p=model-checker.git

diff --git a/datarace.cc b/datarace.cc
index 1040a3b..f0d3dc6 100644
--- a/datarace.cc
+++ b/datarace.cc
@@ -5,14 +5,17 @@
 
 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));
 	}
@@ -40,6 +43,10 @@ static bool clock_may_race(ClockVector *clock1, thread_id_t tid1,
 	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;
 
@@ -63,10 +70,12 @@ static void expandRecord(uint64_t * 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);
 
@@ -76,6 +85,9 @@ void fullRaceCheckWrite(thread_id_t thread, uint64_t * shadow, ClockVector *curr
 		modelclock_t readClock = record->readClock[i];
 		thread_id_t readThread = record->thread[i];
 
+		/* 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();
@@ -98,6 +110,7 @@ void fullRaceCheckWrite(thread_id_t thread, uint64_t * shadow, ClockVector *curr
 	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;
@@ -140,6 +153,7 @@ void raceCheckWrite(thread_id_t thread, void *location, ClockVector *currClock)
 	*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);
 
@@ -161,9 +175,13 @@ void fullRaceCheckRead(thread_id_t thread, uint64_t * shadow, ClockVector *currC
 		modelclock_t readClock = record->readClock[i];
 		thread_id_t readThread = record->thread[i];
 
-		/* TODO: should this have different logic than all the other
-		 * 'clock_may_race' calls? */
-		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];
@@ -193,6 +211,7 @@ void fullRaceCheckRead(thread_id_t thread, uint64_t * shadow, ClockVector *currC
 	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;