76030 - cflow optimizations. Part 1 fix - use counters rather than stacks when we can.

6 files changed, 197 insertions, 0 deletions

diff --git a/runtime/src/org/aspectj/runtime/internal/CFlowCounter.java b/runtime/src/org/aspectj/runtime/internal/CFlowCounter.java
new file mode 100644
index 000000000..e48f67864
--- /dev/null
+++ b/runtime/src/org/aspectj/runtime/internal/CFlowCounter.java
@@ -0,0 +1,75 @@
+/* *******************************************************************
+ * Copyright (c) 2004 IBM Corporation
+ * 
+ * All rights reserved. 
+ * This program and the accompanying materials are made available 
+ * under the terms of the Common Public License v1.0 
+ * which accompanies this distribution and is available at 
+ * http://www.eclipse.org/legal/cpl-v10.html 
+ *  
+ * Contributors: 
+ *    Andy Clement     initial implementation 
+ * ******************************************************************/
+
+
+package org.aspectj.runtime.internal;
+
+import org.aspectj.runtime.internal.cflowstack.ThreadCounter;
+import org.aspectj.runtime.internal.cflowstack.ThreadStackFactory;
+import org.aspectj.runtime.internal.cflowstack.ThreadStackFactoryImpl;
+import org.aspectj.runtime.internal.cflowstack.ThreadStackFactoryImpl11;
+
+
+public class CFlowCounter {
+	
+	private static ThreadStackFactory tsFactory;
+	private ThreadCounter flowHeightHandler;
+
+	static {
+		selectFactoryForVMVersion();
+	}
+	
+	public CFlowCounter() {
+		flowHeightHandler = tsFactory.getNewThreadCounter();
+	}
+    
+    public void inc() {
+    	flowHeightHandler.inc();
+    }
+
+    public void dec() {
+    	flowHeightHandler.dec();
+    }
+    
+    public boolean isValid() {
+    	return flowHeightHandler.isNotZero();
+    }
+
+
+	private static ThreadStackFactory getThreadLocalStackFactory()      { return new ThreadStackFactoryImpl(); }
+	private static ThreadStackFactory getThreadLocalStackFactoryFor11() { return new ThreadStackFactoryImpl11(); }
+    
+	private static void selectFactoryForVMVersion() {
+		String override = System.getProperty("aspectj.runtime.cflowstack.usethreadlocal","unspecified");
+		boolean useThreadLocalImplementation = false;
+		if (override.equals("unspecified")) {
+			String v = System.getProperty("java.class.version","0.0");
+			// Java 1.2 is version 46.0 and above
+			useThreadLocalImplementation = (v.compareTo("46.0") >= 0);
+		} else {
+			useThreadLocalImplementation = override.equals("yes") || override.equals("true");
+		}
+		// System.err.println("Trying to use thread local implementation? "+useThreadLocalImplementation);
+		if (useThreadLocalImplementation) {
+			tsFactory = getThreadLocalStackFactory();
+		} else {
+			tsFactory = getThreadLocalStackFactoryFor11();
+		}
+	}
+	
+	//  For debug ...
+	public static String getThreadStackFactoryClassName() {
+		return tsFactory.getClass().getName();
+	}
+
+}
diff --git a/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadCounter.java b/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadCounter.java
new file mode 100644
index 000000000..96f136ec3
--- /dev/null
+++ b/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadCounter.java
@@ -0,0 +1,21 @@
+/* *******************************************************************
+ * Copyright (c) 2004 IBM Corporation
+ * 
+ * All rights reserved. 
+ * This program and the accompanying materials are made available 
+ * under the terms of the Common Public License v1.0 
+ * which accompanies this distribution and is available at 
+ * http://www.eclipse.org/legal/cpl-v10.html 
+ *  
+ * Contributors: 
+ *    Andy Clement     initial implementation 
+ * ******************************************************************/
+
+package org.aspectj.runtime.internal.cflowstack;
+
+
+public interface ThreadCounter {
+	  public void          inc();
+	  public void          dec();
+	  public boolean isNotZero();
+}
\ No newline at end of file
diff --git a/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadCounterImpl11.java b/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadCounterImpl11.java
new file mode 100644
index 000000000..997f5fed3
--- /dev/null
+++ b/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadCounterImpl11.java
@@ -0,0 +1,74 @@
+/* *******************************************************************
+ * Copyright (c) 2004 IBM Corporation
+ * 
+ * All rights reserved. 
+ * This program and the accompanying materials are made available 
+ * under the terms of the Common Public License v1.0 
+ * which accompanies this distribution and is available at 
+ * http://www.eclipse.org/legal/cpl-v10.html 
+ *  
+ * Contributors: 
+ *    Andy Clement     initial implementation 
+ * 					   Copied from bits of original CFlowStack
+ * ******************************************************************/
+package org.aspectj.runtime.internal.cflowstack;
+
+import java.util.Iterator;
+import java.util.List;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.Hashtable;
+
+public class ThreadCounterImpl11 implements ThreadCounter {
+	private Hashtable counters = new Hashtable();
+	private Thread cached_thread;
+	private Counter cached_counter;
+	
+	private int change_count = 0;
+	private static final int COLLECT_AT = 20000;
+	private static final int MIN_COLLECT_AT = 100; 
+	
+	static class Counter {
+		protected int value = 0;
+	}
+
+	private synchronized Counter getThreadCounter() {
+		if (Thread.currentThread() != cached_thread) {
+			cached_thread = Thread.currentThread();
+			cached_counter = (Counter)counters.get(cached_thread);
+			if (cached_counter == null) {
+				cached_counter = new Counter();
+				counters.put(cached_thread, cached_counter);
+			}
+			change_count++;
+			// Collect more often if there are many threads, but not *too* often
+			int size = Math.max(1, counters.size()); // should be >1 b/c always live threads, but...
+			if (change_count > Math.max(MIN_COLLECT_AT, COLLECT_AT/size)) {
+				List dead_stacks = new ArrayList();
+				for (Enumeration e = counters.keys(); e.hasMoreElements(); ) {
+					Thread t = (Thread)e.nextElement();
+					if (!t.isAlive()) dead_stacks.add(t);
+				}
+				for (Iterator e = dead_stacks.iterator(); e.hasNext(); ) {
+					Thread t = (Thread)e.next();
+					counters.remove(t);
+				}
+				change_count = 0;
+			}
+		}
+		return cached_counter;
+	}
+
+	public void inc() {
+		getThreadCounter().value++;
+	}
+
+	public void dec() {
+		getThreadCounter().value--;
+	}
+
+	public boolean isNotZero() {
+		return getThreadCounter().value!=0;
+	}
+
+}
diff --git a/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadStackFactory.java b/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadStackFactory.java
index d382acbc8..b79b63a98 100644
--- a/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadStackFactory.java
+++ b/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadStackFactory.java
@@ -15,5 +15,6 @@ package org.aspectj.runtime.internal.cflowstack;
 public interface ThreadStackFactory {
 	
   public ThreadStack getNewThreadStack();  
+  public ThreadCounter getNewThreadCounter();
   
 }
diff --git a/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadStackFactoryImpl.java b/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadStackFactoryImpl.java
index d39b7fcb6..98ca2f4b5 100644
--- a/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadStackFactoryImpl.java
+++ b/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadStackFactoryImpl.java
@@ -28,5 +28,27 @@ public class ThreadStackFactoryImpl implements ThreadStackFactory {
 	public ThreadStack getNewThreadStack() {
 		return new ThreadStackImpl();
 	}
+	
+	private static class ThreadCounterImpl extends ThreadLocal implements ThreadCounter {
+		
+		public Object initialValue() {
+		  return new Counter();
+		}
+		public Counter getThreadCounter() {
+			return (Counter)get();
+		}
+		
+		public void inc() { getThreadCounter().value++; }
+		public void dec() { getThreadCounter().value--; }
+		public boolean isNotZero() { return getThreadCounter().value!= 0; }
+		
+		static class Counter {
+		  protected int value = 0;
+		}
+	}
+	
+	public ThreadCounter getNewThreadCounter() {
+		return new ThreadCounterImpl();
+	}
 
 }
diff --git a/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadStackFactoryImpl11.java b/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadStackFactoryImpl11.java
index 350a68109..f4d2a2230 100644
--- a/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadStackFactoryImpl11.java
+++ b/runtime/src/org/aspectj/runtime/internal/cflowstack/ThreadStackFactoryImpl11.java
@@ -18,5 +18,9 @@ public class ThreadStackFactoryImpl11 implements ThreadStackFactory {
 	public ThreadStack getNewThreadStack() {
 		return new ThreadStackImpl11();
 	}
+	
+	public ThreadCounter getNewThreadCounter() {
+		return new ThreadCounterImpl11();
+	}
 
 }