From: Brian Norris <banorris@uci.edu>
Date: Thu, 1 Nov 2012 19:53:01 +0000 (-0700)
Subject: clockvector: bugfix - bad clock merge
X-Git-Tag: pldi2013~30
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=commitdiff_plain;h=a09a4346390cc28a29428ee5a0610b1054aa48ed

clockvector: bugfix - bad clock merge

The clock merge function had a really bad bug, where it would copy
garbage into the new clock vector, if the earlier clock vector (cv) was
"wider" than the current clock vector (this).

Now, ClockVector::merge is much simpler and much less buggy.
---

diff --git a/clockvector.cc b/clockvector.cc
index 062ac41..740b5cf 100644
--- a/clockvector.cc
+++ b/clockvector.cc
@@ -40,27 +40,15 @@ ClockVector::~ClockVector()
  */
 void ClockVector::merge(const ClockVector *cv)
 {
-	modelclock_t *clk = clock;
-	bool resize = false;
-
 	ASSERT(cv != NULL);
 
-	if (cv->num_threads > num_threads) {
-		resize = true;
-		clk = (modelclock_t *)snapshot_malloc(cv->num_threads * sizeof(modelclock_t));
-	}
+	if (cv->num_threads > num_threads)
+		clock = (modelclock_t *)snapshot_realloc(clock, cv->num_threads * sizeof(modelclock_t));
 
 	/* Element-wise maximum */
-	for (int i = 0; i < num_threads; i++)
-		clk[i] = std::max(clock[i], cv->clock[i]);
-
-	if (resize) {
-		for (int i = num_threads; i < cv->num_threads; i++)
-			clk[i] = cv->clock[i];
-		num_threads = cv->num_threads;
-		snapshot_free(clock);
-	}
-	clock = clk;
+	for (int i = 0; i < cv->num_threads; i++)
+		if (cv->clock[i] > clock[i])
+			clock[i] = cv->clock[i];
 }
 
 /**