From fbeeeb53fdbcb6b59e35c910e732173c6ead5e79 Mon Sep 17 00:00:00 2001
From: weiyu <weiyuluo1232@gmail.com>
Date: Mon, 20 Apr 2020 15:58:30 -0700
Subject: [PATCH] Optimize RaceCheckRead

---
 datarace.cc | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 datarace.h  |  2 ++
 librace.cc  | 18 +++++++++++---
 3 files changed, 89 insertions(+), 3 deletions(-)

diff --git a/datarace.cc b/datarace.cc
index 4558e2ba..8af2b1e6 100644
--- a/datarace.cc
+++ b/datarace.cc
@@ -703,3 +703,75 @@ Exit:
 		else model_free(race);
 	}
 }
+
+void raceCheckReadOpt(thread_id_t thread, const void * addr, int bytes)
+{
+	const ModelExecution * execution = get_execution();
+	ClockVector *currClock = execution->get_cv(thread);
+	if (currClock == NULL)
+		return;
+
+	int threadid = id_to_int(thread);
+	modelclock_t ourClock = currClock->getClock(thread);
+	bool should_expand = threadid > MAXTHREADID || ourClock > MAXWRITEVECTOR;
+
+	bool hasRace = false;
+
+	for (int i = 0; i < bytes; i++) {
+		const void * location = (void *)(((uintptr_t)addr) + i);
+		uint64_t *shadow = lookupAddressEntry(location);
+		uint64_t shadowval = *shadow;
+
+		struct DataRace * race = NULL;
+
+		/* Do full record */
+		if (shadowval != 0 && !ISSHORTRECORD(shadowval)) {
+			race = fullRaceCheckRead(thread, location, shadow, currClock);
+			goto Exit;
+		}
+
+		{
+			/* Thread ID is too large or clock is too large. */
+			if (should_expand) {
+				expandRecord(shadow);
+				race = fullRaceCheckRead(thread, location, shadow, currClock);
+				goto Exit;
+			}
+
+			/* Check for datarace against last write. */
+
+			modelclock_t writeClock = WRITEVECTOR(shadowval);
+			thread_id_t writeThread = int_to_id(WRTHREADID(shadowval));
+
+			// If there is already has a race, skip check
+			if (!hasRace && clock_may_race(currClock, thread, writeClock, writeThread)) {
+				/* We have a datarace */
+				race = reportDataRace(writeThread, writeClock, true, execution->get_parent_action(thread), false, location);
+			}
+
+			modelclock_t readClock = READVECTOR(shadowval);
+			thread_id_t readThread = int_to_id(RDTHREADID(shadowval));
+
+			if (clock_may_race(currClock, thread, readClock, readThread)) {
+				/* We don't subsume this read... Have to expand record. */
+				expandRecord(shadow);
+				struct RaceRecord *record = (struct RaceRecord *) (*shadow);
+				record->thread[1] = thread;
+				record->readClock[1] = ourClock;
+				record->numReads++;
+
+				goto Exit;
+			}
+
+			*shadow = ENCODEOP(threadid, ourClock, id_to_int(writeThread), writeClock) | (shadowval & ATOMICMASK);
+		}
+Exit:
+		if (race) {
+			hasRace = true;
+			race->numframes=backtrace(race->backtrace, sizeof(race->backtrace)/sizeof(void*));
+			if (raceset->add(race))
+				assert_race(race);
+			else model_free(race);
+		}
+	}
+}
diff --git a/datarace.h b/datarace.h
index f026556a..60392029 100644
--- a/datarace.h
+++ b/datarace.h
@@ -46,6 +46,8 @@ void initRaceDetector();
 void raceCheckWrite(thread_id_t thread, void *location);
 void atomraceCheckWrite(thread_id_t thread, void *location);
 void raceCheckRead(thread_id_t thread, const void *location);
+void raceCheckReadOpt(thread_id_t thread, const void *location, int bytes);
+
 void atomraceCheckRead(thread_id_t thread, const void *location);
 void recordWrite(thread_id_t thread, void *location);
 void recordCalloc(void *location, size_t size);
diff --git a/librace.cc b/librace.cc
index faa98cdb..15ee94eb 100644
--- a/librace.cc
+++ b/librace.cc
@@ -152,31 +152,42 @@ void cds_load8(const void *addr) {
 	if (!model)
 		return;
 	thread_id_t tid = thread_current()->get_id();
-	raceCheckRead(tid, addr);
+
+	raceCheckReadOpt(tid, addr, 1);
+//	raceCheckRead(tid, addr);
 }
 
 void cds_load16(const void *addr) {
 	if (!model)
 		return;
 	thread_id_t tid = thread_current()->get_id();
-	raceCheckRead(tid, addr);
-	raceCheckRead(tid, (const void *)(((uintptr_t)addr) + 1));
+
+	raceCheckReadOpt(tid, addr, 2);
+//	raceCheckRead(tid, addr);
+//	raceCheckRead(tid, (const void *)(((uintptr_t)addr) + 1));
 }
 
 void cds_load32(const void *addr) {
 	if (!model)
 		return;
 	thread_id_t tid = thread_current()->get_id();
+
+	raceCheckReadOpt(tid, addr, 4);
+/*
 	raceCheckRead(tid, addr);
 	raceCheckRead(tid, (const void *)(((uintptr_t)addr) + 1));
 	raceCheckRead(tid, (const void *)(((uintptr_t)addr) + 2));
 	raceCheckRead(tid, (const void *)(((uintptr_t)addr) + 3));
+*/
 }
 
 void cds_load64(const void *addr) {
 	if (!model)
 		return;
 	thread_id_t tid = thread_current()->get_id();
+
+	raceCheckReadOpt(tid, addr, 8);
+/*
 	raceCheckRead(tid, addr);
 	raceCheckRead(tid, (const void *)(((uintptr_t)addr) + 1));
 	raceCheckRead(tid, (const void *)(((uintptr_t)addr) + 2));
@@ -185,4 +196,5 @@ void cds_load64(const void *addr) {
 	raceCheckRead(tid, (const void *)(((uintptr_t)addr) + 5));
 	raceCheckRead(tid, (const void *)(((uintptr_t)addr) + 6));
 	raceCheckRead(tid, (const void *)(((uintptr_t)addr) + 7));
+*/
 }
-- 
2.34.1