[RFA/JVMTI] Set/Clear Breakpoint

[Keith Seitz <keiths at redhat dot com>]

Hi,

The following patch adds two new gnu.gcj.jvmti classes that are used by 
the JVMTI code to implement the JVMTI calls SetBreakpoint and 
ClearBreakpoint.

Keith

ChangeLog
2006-10-30  Keith Seitz  <keiths@redhat.com>

        * gnu/gcj/jvmti/Location.java: New file.
        * gnu/gcj/jvmti/BreakpointManager.java: New file.
        * jvmti.cc (_Jv_JVMTI_SetBreakpoint): New function.
        (_Jv_JVMTI_ClearBreakpoint): New function.
        (_Jv_JVMTI_Interface): Define SetBreakpoint and ClearBreakpoint.
        * sources.am: Regenerated.
        * Makefile.in: Regenerated.

Index: gnu/gcj/jvmti/Location.java
===================================================================
--- gnu/gcj/jvmti/Location.java	(revision 0)
+++ gnu/gcj/jvmti/Location.java	(revision 0)
@@ -0,0 +1,60 @@
+// Location.java - a wrapper class for breakpoint locations in JVMTI
+
+/* Copyright (C) 2006  Free Software Foundation
+
+   This file is part of libgcj.
+
+This software is copyrighted work licensed under the terms of the
+Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
+details.  */
+
+package gnu.gcj.jvmti;
+
+import java.lang.Long;
+
+/**
+ * This class represents a breakpoint location (pair<jmethodID,jlocation>).
+ * BreakpointManager uses this class as a key in the Map of installed
+ * breakpoints.
+ *
+ * @author Keith Seitz (keiths@redhat.com)
+ */
+public class Location
+{
+  // method (a jmethodID in JVMTI)
+  private long method;
+
+  // index (a jlocation in JVMTI)
+  private long location;
+
+  /**
+   * Constructor
+   *
+   * @param method   the method defined by this location (a jmethodID)
+   * @param location the integer index of the insn in the method (a jlocation)
+   */
+  public Location (long method, long location)
+  {
+    this.method = method;
+    this.location = location;
+  }
+
+  public int hashCode ()
+  {
+    return toString ().hashCode ();
+  }
+
+  public boolean equals (Object obj)
+  {
+    Location loc = (Location) obj;
+    return (loc.method == method && loc.location == location);
+  }
+
+  /**
+   * Converts the Location to a String
+   */
+  public String toString ()
+  {
+    return Long.toHexString (method) + "." + Long.toString (location);
+  }
+}
Index: gnu/gcj/jvmti/BreakpointManager.java
===================================================================
--- gnu/gcj/jvmti/BreakpointManager.java	(revision 0)
+++ gnu/gcj/jvmti/BreakpointManager.java	(revision 0)
@@ -0,0 +1,76 @@
+// BreakpointManager.java - A convenience class for dealing with breakpoints
+
+/* Copyright (C) 2006  Free Software Foundation
+
+   This file is part of libgcj.
+
+This software is copyrighted work licensed under the terms of the
+Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
+details.  */
+
+package gnu.gcj.jvmti;
+
+import java.util.Hashtable;
+
+/**
+ * A class which manages breakpoints in the VM interpreter engine.
+ *
+ * BreakpointManager is a location manager that the interpreter
+ * uses to lookup the original instruction for any given installed
+ * breakpoint. JVMTI does not allow multiple breakpoints to be set
+ * at any given location.
+ *
+ * @author Keith Seitz (keiths@redhat.com)
+ */
+public class BreakpointManager
+{
+  private static BreakpointManager _instance = new BreakpointManager ();
+
+  // List of breakpoints indexed by Location
+  private Hashtable _breakpoints;
+
+  private BreakpointManager ()
+  {
+    _breakpoints = new Hashtable ();
+  }
+
+  /**
+   * Creates a new breakpoint. SetBreakpoint will verify the validity
+   * of the arguments.
+   *
+   * @param method  method in which to set breakpoint (a jmethodID)
+   * @param location index where the breakpoint is to be set (a jlocation)
+   */
+  public static Breakpoint newBreakpoint (long method, long location)
+  {
+    Breakpoint bp = new Breakpoint (method, location);
+    Location loc = new Location (method, location);
+    _instance._breakpoints.put (loc, bp);
+    return bp;
+  }
+
+  /**
+   * Deletes the breakpoint at the given Location
+   *
+   * @param method method in which to clear breakpoint
+   * @param location index of breakpoint in method
+   */
+  public static void deleteBreakpoint (long method, long location)
+  {
+    Location loc = new Location (method, location);
+    _instance._breakpoints.remove (loc);
+  }
+
+  /**
+   * Returns the breakpoint at the given location or null if none installed
+   * at location
+   *
+   * @param method the jmethodID of the breakpoint location
+   * @param location the index in the method
+   */
+  public static Breakpoint getBreakpoint (long method, long location)
+  {
+    Location loc = new Location (method, location);
+    return (Breakpoint) _instance._breakpoints.get (loc);
+  }
+}
Index: jvmti.cc
===================================================================
--- jvmti.cc	(revision 118100)
+++ jvmti.cc	(working copy)
@@ -14,6 +14,7 @@
 #include <jvm.h>
 #include <java-threads.h>
 #include <java-gc.h>
+#include <java-interp.h>
 #include <jvmti.h>
 #include "jvmti-int.h"
 
@@ -21,6 +22,9 @@
 
 #include <gnu/classpath/SystemProperties.h>
 #include <gnu/gcj/runtime/BootClassLoader.h>
+#include <gnu/gcj/jvmti/Breakpoint.h>
+#include <gnu/gcj/jvmti/BreakpointManager.h>
+
 #include <java/lang/Class.h>
 #include <java/lang/ClassLoader.h>
 #include <java/lang/Object.h>
@@ -280,6 +284,72 @@
 }
 
 static jvmtiError JNICALL
+_Jv_JVMTI_SetBreakpoint (jvmtiEnv *env, jmethodID method, jlocation location)
+{
+  REQUIRE_PHASE (env, JVMTI_PHASE_LIVE);
+
+  using namespace gnu::gcj::jvmti;
+  Breakpoint *bp
+    = BreakpointManager::getBreakpoint (reinterpret_cast<jlong> (method),
+					location);
+  if (bp == NULL)
+    {
+      jclass klass;
+      jvmtiError err = env->GetMethodDeclaringClass (method, &klass);
+      if (err != JVMTI_ERROR_NONE)
+	return err;
+
+      if (!_Jv_IsInterpretedClass (klass))
+	return JVMTI_ERROR_INVALID_CLASS;
+
+      _Jv_MethodBase *base = _Jv_FindInterpreterMethod (klass, method);
+      if (base == NULL)
+	return JVMTI_ERROR_INVALID_METHODID;
+
+      jint flags;
+      err = env->GetMethodModifiers (method, &flags);
+      if (err != JVMTI_ERROR_NONE)
+	return err;
+
+      if (flags & java::lang::reflect::Modifier::NATIVE)
+	return JVMTI_ERROR_NATIVE_METHOD;
+
+      _Jv_InterpMethod *imeth = reinterpret_cast<_Jv_InterpMethod *> (base);
+      if (imeth->get_insn (location) == NULL)
+	return JVMTI_ERROR_INVALID_LOCATION;
+
+      // Now the breakpoint can be safely installed
+      bp = BreakpointManager::newBreakpoint (reinterpret_cast<jlong> (method),
+					     location);
+    }
+  else
+    {
+      // Duplicate breakpoints are not permitted by JVMTI
+      return JVMTI_ERROR_DUPLICATE;
+    }
+
+  return JVMTI_ERROR_NONE;
+}
+
+static jvmtiError JNICALL
+_Jv_JVMTI_ClearBreakpoint (MAYBE_UNUSED jvmtiEnv *env, jmethodID method,
+			   jlocation location)
+{
+  REQUIRE_PHASE (env, JVMTI_PHASE_LIVE);
+
+  using namespace gnu::gcj::jvmti;
+
+  Breakpoint *bp
+    = BreakpointManager::getBreakpoint (reinterpret_cast<jlong> (method),
+					location);
+  if (bp == NULL)
+    return JVMTI_ERROR_NOT_FOUND;
+
+  BreakpointManager::deleteBreakpoint (reinterpret_cast<jlong> (method), location);
+  return JVMTI_ERROR_NONE;
+}
+
+static jvmtiError JNICALL
 _Jv_JVMTI_Allocate (MAYBE_UNUSED jvmtiEnv *env, jlong size,
 		    unsigned char **result)
 {
@@ -1278,8 +1348,8 @@
   _Jv_JVMTI_RawMonitorWait,	// RawMonitorWait
   _Jv_JVMTI_RawMonitorNotify,	// RawMonitorNotify
   _Jv_JVMTI_RawMonitorNotifyAll, // RawMonitorNotifyAll
-  UNIMPLEMENTED,		// SetBreakpoint
-  UNIMPLEMENTED,		// ClearBreakpoint
+  _Jv_JVMTI_SetBreakpoint,	// SetBreakpoint
+  _Jv_JVMTI_ClearBreakpoint,	// ClearBreakpoint
   RESERVED,			// reserved40
   UNIMPLEMENTED,		// SetFieldAccessWatch
   UNIMPLEMENTED,		// ClearFieldAccessWatch