[vmkit-commits] [PATCH] Update OpenJDK's classpath reflect--fix field layout and class mapping

[Will Dietz]

Inlined below.

This raises a question that I'm not sure I have a good answer to in
general: how to replace the various 'vmdata' mappings that GNU
Classpath so nicely provides?

Here I stash things in a static map, and it seems to work fine.  However:
a)where does the map really belong? The Jnjvm?
b)seems like a bad idea to put GC'd pointers in a stl container, but I
could be wrong.

Is there a general way to map /from/ a JavaObject?

We have this issue with java.lang.Thread -> JavaThread, and
java.lang.ClassLoader -> JnjvmClassLoader (don't bother with
VMClassLoader intermediate in OpenJDK port, maybe that's a mistake),
so this is worth discussing/solving.

However those instances I'm able to abuse existing fields ('eetop' for
JavaThread, and 'classes' for ClassLoader), and the biggest issues
there seems to be ensuring that plays nice with GC stuff.

Anyway, thoughts welcome :).

~Will


>From 4e25b2c950aff018261054ca13baeeadb72d6df1 Mon Sep 17 00:00:00 2001
From: Will Dietz <w at wdtz.org>
Date: Wed, 26 Oct 2011 18:23:38 -0500
Subject: [PATCH 1/2] Update classpathreflect--field layout, class mapping.

---
 lib/J3/ClassLib/OpenJDK/ClasspathReflect.cpp |    1 +
 lib/J3/ClassLib/OpenJDK/ClasspathReflect.h   |   47 ++++++++-----------------
 2 files changed, 16 insertions(+), 32 deletions(-)

diff --git a/lib/J3/ClassLib/OpenJDK/ClasspathReflect.cpp
b/lib/J3/ClassLib/OpenJDK/ClasspathReflect.cpp
index 3d69fa4..31dd417 100644
--- a/lib/J3/ClassLib/OpenJDK/ClasspathReflect.cpp
+++ b/lib/J3/ClassLib/OpenJDK/ClasspathReflect.cpp
@@ -14,6 +14,7 @@

 namespace j3 {

+std::map<JavaObjectClass*, UserCommonClass*> JavaObjectClass::ClassMap;
 JavaMethod* JavaObjectConstructor::getInternalMethod(JavaObjectConstructor*
self) {
   llvm_gcroot(self, 0);
   UserCommonClass* cls = JavaObjectClass::getClass(self->declaringClass);
diff --git a/lib/J3/ClassLib/OpenJDK/ClasspathReflect.h
b/lib/J3/ClassLib/OpenJDK/ClasspathReflect.h
index 08042b3..101e726 100644
--- a/lib/J3/ClassLib/OpenJDK/ClasspathReflect.h
+++ b/lib/J3/ClassLib/OpenJDK/ClasspathReflect.h
@@ -16,25 +16,27 @@
 #include "JavaObject.h"
 #include "JavaThread.h"

+#include <map>
 namespace j3 {

 class JavaObjectClass : public JavaObject {
 private:
-  JavaObject* signers;
-  JavaObject* pd;
-  UserCommonClass* vmdata;
+  static std::map<JavaObjectClass*, UserCommonClass*> ClassMap;
   JavaObject* constructor;
+  JavaObject* newInstanceCallerCache;
+  JavaObject* name;
+  JavaObject* pd;

 public:

   static UserCommonClass* getClass(JavaObjectClass* cl) {
     llvm_gcroot(cl, 0);
-    return cl->vmdata;
+    return ClassMap[cl];
   }

   static void setClass(JavaObjectClass* cl, UserCommonClass* vmdata) {
     llvm_gcroot(cl, 0);
-    cl->vmdata = vmdata;
+    ClassMap[cl] = vmdata;
   }

   static void setProtectionDomain(JavaObjectClass* cl, JavaObject* pd) {
@@ -50,11 +52,12 @@ public:
   }

   static void staticTracer(JavaObjectClass* obj, word_t closure) {
-    mvm::Collector::markAndTrace(obj, &obj->pd, closure);
-    mvm::Collector::markAndTrace(obj, &obj->signers, closure);
     mvm::Collector::markAndTrace(obj, &obj->constructor, closure);
-    if (obj->vmdata) {
-      JavaObject** Obj = obj->vmdata->classLoader->getJavaClassLoaderPtr();
+    mvm::Collector::markAndTrace(obj, &obj->newInstanceCallerCache, closure);
+    mvm::Collector::markAndTrace(obj, &obj->name, closure);
+    mvm::Collector::markAndTrace(obj, &obj->pd, closure);
+    if (ClassMap[obj]) {
+      JavaObject** Obj = ClassMap[obj]->classLoader->getJavaClassLoaderPtr();
       if (*Obj) mvm::Collector::markAndTraceRoot(Obj, closure);
     }
   }
@@ -64,8 +67,8 @@ class JavaObjectField : public JavaObject {
 private:
   uint8 flag;
   JavaObjectClass* declaringClass;
-  JavaObject* name;
   uint32 slot;
+  JavaObject* name;

 public:

@@ -92,8 +95,8 @@ class JavaObjectMethod : public JavaObject {
 private:
   uint8 flag;
   JavaObjectClass* declaringClass;
-  JavaObject* name;
   uint32 slot;
+  JavaObject* name;

 public:

@@ -133,32 +136,12 @@ public:

 };

-class JavaObjectVMThread : public JavaObject {
-private:
-  JavaObject* thread;
-  bool running;
-  JavaThread* vmdata;
-
-public:
-  static void staticTracer(JavaObjectVMThread* obj, word_t closure) {
-    mvm::Collector::markAndTrace(obj, &obj->thread, closure);
-  }
-
-  static void setVmdata(JavaObjectVMThread* vmthread,
-                        JavaThread* internal_thread) {
-    llvm_gcroot(vmthread, 0);
-    vmthread->vmdata = internal_thread;
-  }
-
-};
-
-
 class JavaObjectThrowable : public JavaObject {
 private:
+  JavaObject* backtrace;
   JavaObject* detailedMessage;
   JavaObject* cause;
   JavaObject* stackTrace;
-  JavaObject* vmState;

 public:

-- 
1.7.5.1