From 0db9fc67452e396fa3e4953328f30e18551d34e1 Mon Sep 17 00:00:00 2001
From: Peizhao Ou <peizhaoo@uci.edu>
Date: Fri, 13 Feb 2015 10:49:04 -0800
Subject: [PATCH] changes

---
 treiber-stack/Makefile         |  1 +
 treiber-stack/stack.h          | 17 +++++++++++------
 treiber-stack/stack_wildcard.h | 21 +++++++++++++--------
 treiber-stack/testcase1.cc     |  4 ++++
 4 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/treiber-stack/Makefile b/treiber-stack/Makefile
index 40b3cb5..6e8bbfe 100644
--- a/treiber-stack/Makefile
+++ b/treiber-stack/Makefile
@@ -10,6 +10,7 @@ TESTS := $(NORMAL_TESTS) $(WILDCARD_TESTS)
 
 all: $(TESTS)
 
+$(WILDCARD_TESTS): CXXFLAGS += -DWILDCARD
 $(WILDCARD_TESTS): %_wildcard : %.cc $(BENCH)_wildcard.h 
 	$(CXX) -o $@ $^ $(CXXFLAGS) $(LDFLAGS)
 
diff --git a/treiber-stack/stack.h b/treiber-stack/stack.h
index de551cb..4428876 100644
--- a/treiber-stack/stack.h
+++ b/treiber-stack/stack.h
@@ -8,7 +8,10 @@
 
 struct node {
 	unsigned int value;
-	node *next;
+	// This field does not have to be atomic, but in the inference analysis, we
+	// might have a data race for this field without the proper synchronization.
+	//node *next;
+	atomic<node*> next;
 
 	node(unsigned int v) {
 		value = v;
@@ -25,10 +28,11 @@ struct stack {
 
 	void push(unsigned int val) {
 		node *n = new node(val);
-		node *old = top.load(acquire);
+		node *old = top.load(relaxed);
 		do {
-			n->next = old;
-		} while (!top.compare_exchange_strong(old, n, acq_rel, relaxed));
+			// n->next = old;
+			n->next.store(old, relaxed);
+		} while (!top.compare_exchange_strong(old, n, release, relaxed));
 	}
 
 	unsigned int pop() {
@@ -37,8 +41,9 @@ struct stack {
 		do {
 			if (!old)
 				return 0;
-			n = old->next;
-		} while (!top.compare_exchange_strong(old, n, acq_rel, acquire));
+			//n = old->next;
+			n = old->next.load(relaxed);
+		} while (!top.compare_exchange_strong(old, n, relaxed, relaxed));
 		return old->value;
 	}
 };
diff --git a/treiber-stack/stack_wildcard.h b/treiber-stack/stack_wildcard.h
index 75c375a..72a761a 100644
--- a/treiber-stack/stack_wildcard.h
+++ b/treiber-stack/stack_wildcard.h
@@ -10,7 +10,10 @@
 
 struct node {
 	unsigned int value;
-	node *next;
+	// This field does not have to be atomic, but in the inference analysis, we
+	// might have a data race for this field without the proper synchronization.
+	//node *next;
+	atomic<node*> next;
 
 	node(unsigned int v) {
 		value = v;
@@ -29,20 +32,22 @@ struct stack {
 		node *n = new node(val);
 		node *old = top.load(wildcard(1)); // acquire
 		do {
-			n->next = old;
-		} while (!top.compare_exchange_strong(old, n, wildcard(2), wildcard(3)));
-		// acq_rel & relaxed
+			// n->next = old;
+			n->next.store(old, wildcard(2));
+		} while (!top.compare_exchange_strong(old, n, wildcard(3), wildcard(4)));
+		// relaxed & relaxed
 	}
 
 	unsigned int pop() {
-		node *old = top.load(wildcard(4)); // acquire
+		node *old = top.load(wildcard(5)); // acquire
 		node *n;
 		do {
 			if (!old)
 				return 0;
-			n = old->next;
-		} while (!top.compare_exchange_strong(old, n, wildcard(5), wildcard(6)));
-		// acq_rel & acquire
+			// n = old->next;
+			n = old->next.load(relaxed);
+		} while (!top.compare_exchange_strong(old, n, wildcard(6), wildcard(7)));
+		// relaxed & relaxed 
 		return old->value;
 	}
 };
diff --git a/treiber-stack/testcase1.cc b/treiber-stack/testcase1.cc
index 7ca474d..dc76ebf 100644
--- a/treiber-stack/testcase1.cc
+++ b/treiber-stack/testcase1.cc
@@ -3,7 +3,11 @@
 #include <threads.h>
 #include "model-assert.h"
 
+#ifdef WILDCARD
+#include "stack_wildcard.h"
+#else
 #include "stack.h"
+#endif
 
 static int procs = 4;
 static stack *s;
-- 
2.34.1