8346142: [perf] scalability issue for the specjvm2008::xml.validation workload

Reviewed-by: joehw

Author: Vladimir Ivanov

src/java.xml/share/classes/com/sun/org/apache/xerces/internal/impl/xpath/regex/RegularExpression.java

@@ -705,11 +705,13 @@ public boolean matches(char[]  target, Match match) {
      */
     public boolean matches(char[] target, int start, int end, Match match) {
 
-        synchronized (this) {
-            if (this.operations == null)
-                this.prepare();
-            if (this.context == null)
-                this.context = new Context();
+        if (this.operations == null || this.context == null) {
+            synchronized (this) {
+                if (this.operations == null)
+                    this.prepare();
+                if (this.context == null)
+                    this.context = new Context();
+            }
         }
         Context con = this.context;
         if (!con.claim()) {
@@ -890,11 +892,13 @@ public boolean matches(String  target, Match match) {
      */
     public boolean matches(String  target, int start, int end, Match match) {
 
-        synchronized (this) {
-            if (this.operations == null)
-                this.prepare();
-            if (this.context == null)
-                this.context = new Context();
+        if (this.operations == null || this.context == null) {
+            synchronized (this) {
+                if (this.operations == null)
+                    this.prepare();
+                if (this.context == null)
+                    this.context = new Context();
+            }
         }
         Context con = this.context;
         if (!con.claim()) {
@@ -1570,11 +1574,13 @@ public boolean matches(CharacterIterator  target, Match match) {
 
 
 
-        synchronized (this) {
-            if (this.operations == null)
-                this.prepare();
-            if (this.context == null)
-                this.context = new Context();
+        if (this.operations == null || this.context == null) {
+            synchronized (this) {
+                if (this.operations == null)
+                    this.prepare();
+                if (this.context == null)
+                    this.context = new Context();
+            }
         }
         Context con = this.context;
         if (!con.claim()) {
@@ -1739,9 +1745,9 @@ else if (this.firstChar != null) {
     boolean hasBackReferences = false;
 
     transient int minlength;
-    transient Op operations = null;
+    transient volatile Op operations = null;
     transient int numberOfClosures;
-    transient Context context = null;
+    transient volatile Context context = null;
     transient RangeToken firstChar = null;
 
     transient String fixedString = null;