Add a callback driven visitor routine and make verify use it.

This is the first step along the way to ending the proliferation of
one-off object walking routines.  This code should supersede similar
code in the mark sweep collector, the copying collector, the hprof
tool, etc..  Once all of its uses have been debugged the routines in
the .c file should be hoisted into the .h file and marked as inline.

Soon, the signature of the visitor will probably have to be converted
to a functor with members specialized to reference type and, in
addition, given an extra parameter for a context structure.

Change-Id: Ib00850f22374c5aca51fa3708304774da90d8bc4
diff --git a/vm/Dvm.mk b/vm/Dvm.mk
index 81593e5..c9e122e 100644
--- a/vm/Dvm.mk
+++ b/vm/Dvm.mk
@@ -137,6 +137,7 @@
 	alloc/Heap.c.arm \
 	alloc/DdmHeap.c \
 	alloc/Verify.c \
+	alloc/Visit.c \
 	analysis/CodeVerify.c \
 	analysis/DexPrepare.c \
 	analysis/DexVerify.c \
diff --git a/vm/alloc/Verify.c b/vm/alloc/Verify.c
index 212b6ea..a976ce4 100644
--- a/vm/alloc/Verify.c
+++ b/vm/alloc/Verify.c
@@ -15,9 +15,10 @@
  */
 
 #include "Dalvik.h"
+#include "alloc/HeapBitmap.h"
 #include "alloc/HeapSource.h"
 #include "alloc/Verify.h"
-#include "alloc/HeapBitmap.h"
+#include "alloc/Visit.h"
 
 /*
  * Helper routine for verifyRefernce that masks low-tag bits before
@@ -52,133 +53,13 @@
 }
 
 /*
- * Verifies instance fields.
- */
-static void verifyInstanceFields(const Object *obj)
-{
-    ClassObject *clazz;
-    int i;
-
-    assert(obj != NULL);
-    assert(obj->clazz != NULL);
-    LOGV("Entering verifyInstanceFields(obj=%p)", obj);
-    /* TODO(cshapiro): check reference offsets bitmap for agreement. */
-    for (clazz = obj->clazz; clazz != NULL; clazz = clazz->super) {
-        InstField *field = clazz->ifields;
-        for (i = 0; i < clazz->ifieldRefCount; ++i, ++field) {
-            void *addr = BYTE_OFFSET((Object *)obj, field->byteOffset);
-            verifyReference(&((JValue *)addr)->l);
-        }
-    }
-    LOGV("Exiting verifyInstanceFields(obj=%p)", obj);
-}
-
-/*
- * Verifies the header, static field references, and interface
- * pointers of a class object.
- */
-static void verifyClassObject(const ClassObject *obj)
-{
-    int i;
-
-    LOGV("Entering verifyClassObject(obj=%p)", obj);
-    if (obj == gDvm.unlinkedJavaLangClass) {
-        assert(obj->obj.clazz == NULL);
-        goto exit;
-    }
-    verifyReference(&obj->obj.clazz);
-    assert(!strcmp(obj->obj.clazz->descriptor, "Ljava/lang/Class;"));
-    if (IS_CLASS_FLAG_SET(obj, CLASS_ISARRAY)) {
-        verifyReference(&obj->elementClass);
-    }
-    verifyReference(&obj->super);
-    verifyReference(&obj->classLoader);
-    /* Verify static field references. */
-    for (i = 0; i < obj->sfieldCount; ++i) {
-        char ch = obj->sfields[i].field.signature[0];
-        if (ch == '[' || ch == 'L') {
-            verifyReference(&obj->sfields[i].value.l);
-        }
-    }
-    /* Verify the instance fields. */
-    verifyInstanceFields((const Object *)obj);
-    /* Verify interface references. */
-    for (i = 0; i < obj->interfaceCount; ++i) {
-        verifyReference(&obj->interfaces[i]);
-    }
-exit:
-    LOGV("Exiting verifyClassObject(obj=%p)", obj);
-}
-
-/*
- * Verifies the header of all array objects.  If the array object is
- * specialized to a reference type, verifies the array data as well.
- */
-static void verifyArrayObject(const ArrayObject *array)
-{
-    size_t i;
-
-    LOGV("Entering verifyArrayObject(array=%p)", array);
-    /* Verify the class object reference. */
-    assert(array->obj.clazz != NULL);
-    verifyReference(&array->obj.clazz);
-    if (IS_CLASS_FLAG_SET(array->obj.clazz, CLASS_ISOBJECTARRAY)) {
-        /* Verify the array contents. */
-        Object **contents = (Object **)array->contents;
-        for (i = 0; i < array->length; ++i) {
-            verifyReference(&contents[i]);
-        }
-    }
-    LOGV("Exiting verifyArrayObject(array=%p)", array);
-}
-
-/*
- * Verifies the header and field references of a data object.
- */
-static void verifyDataObject(const DataObject *obj)
-{
-    LOGV("Entering verifyDataObject(obj=%p)", obj);
-    /* Verify the class object. */
-    assert(obj->obj.clazz != NULL);
-    verifyReference(&obj->obj.clazz);
-    /* Verify the instance fields. */
-    verifyInstanceFields((const Object *)obj);
-    if (IS_CLASS_FLAG_SET(obj->obj.clazz, CLASS_ISREFERENCE)) {
-        /* Verify the hidden Reference.referent field. */
-        size_t offset = gDvm.offJavaLangRefReference_referent;
-        void *addr = BYTE_OFFSET((Object *)obj, offset);
-        verifyReference(&((JValue *)addr)->l);
-    }
-    LOGV("Exiting verifyDataObject(obj=%p)", obj);
-}
-
-/*
  * Verifies an object reference.  Determines the type of the reference
  * and dispatches to a specialized verification routine.
  */
 void dvmVerifyObject(const Object *obj)
 {
-    ClassObject *clazz;
-
     LOGV("Entering dvmVerifyObject(obj=%p)", obj);
-    assert(obj != NULL);
-    /* Check that the object is aligned. */
-    assert(((uintptr_t)obj & 7) == 0);
-    clazz = obj->clazz;
-    /* Check that the class object is aligned. */
-    assert(((uintptr_t)clazz & 7) == 0);
-    /* Dispatch a type-specific verification routine. */
-    if (clazz == gDvm.classJavaLangClass ||
-        obj == (Object *)gDvm.unlinkedJavaLangClass) {
-        verifyClassObject((ClassObject *)obj);
-    } else {
-        assert(clazz != NULL);
-        if (IS_CLASS_FLAG_SET(clazz, CLASS_ISARRAY)) {
-            verifyArrayObject((ArrayObject *)obj);
-        } else {
-            verifyDataObject((DataObject *)obj);
-        }
-    }
+    dvmVisitObject((Visitor *)verifyReference, (Object *)obj);
     LOGV("Exiting dvmVerifyObject(obj=%p)", obj);
 }
 
diff --git a/vm/alloc/Visit.c b/vm/alloc/Visit.c
new file mode 100644
index 0000000..57de032
--- /dev/null
+++ b/vm/alloc/Visit.c
@@ -0,0 +1,174 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Dalvik.h"
+#include "alloc/clz.h"
+#include "alloc/Visit.h"
+
+/*
+ * Visits the instance fields of a class or data object.
+ */
+static void visitInstanceFields(Visitor *visitor, Object *obj)
+{
+    assert(visitor != NULL);
+    assert(obj != NULL);
+    assert(obj->clazz != NULL);
+    LOGV("Entering visitInstanceFields(visitor=%p,obj=%p)", visitor, obj);
+    if (obj->clazz->refOffsets != CLASS_WALK_SUPER) {
+        size_t refOffsets = obj->clazz->refOffsets;
+        while (refOffsets != 0) {
+            size_t rshift = CLZ(refOffsets);
+            size_t offset = CLASS_OFFSET_FROM_CLZ(rshift);
+            Object **ref = BYTE_OFFSET(obj, offset);
+            (*visitor)(ref);
+            refOffsets &= ~(CLASS_HIGH_BIT >> rshift);
+        }
+    } else {
+        ClassObject *clazz;
+        for (clazz = obj->clazz; clazz != NULL; clazz = clazz->super) {
+            InstField *field = clazz->ifields;
+            int i;
+            for (i = 0; i < clazz->ifieldRefCount; ++i, ++field) {
+                size_t offset = field->byteOffset;
+                Object **ref = BYTE_OFFSET(obj, offset);
+                (*visitor)(ref);
+            }
+        }
+    }
+    LOGV("Exiting visitInstanceFields(visitor=%p,obj=%p)", visitor, obj);
+}
+
+/*
+ * Visits the static fields of a class object.
+ */
+static void visitStaticFields(Visitor *visitor, ClassObject *clazz)
+{
+    int i;
+
+    assert(visitor != NULL);
+    assert(clazz != NULL);
+    for (i = 0; i < clazz->sfieldCount; ++i) {
+        char ch = clazz->sfields[i].field.signature[0];
+        if (ch == '[' || ch == 'L') {
+            (*visitor)(&clazz->sfields[i].value.l);
+        }
+    }
+}
+
+/*
+ * Visit the interfaces of a class object.
+ */
+static void visitInterfaces(Visitor *visitor, ClassObject *clazz)
+{
+    int i;
+
+    assert(visitor != NULL);
+    assert(clazz != NULL);
+    for (i = 0; i < clazz->interfaceCount; ++i) {
+        (*visitor)(&clazz->interfaces[i]);
+    }
+}
+
+/*
+ * Visits all the references stored in a class object instance.
+ */
+static void visitClassObject(Visitor *visitor, ClassObject *obj)
+{
+    assert(visitor != NULL);
+    assert(obj != NULL);
+    LOGV("Entering visitClassObject(visitor=%p,obj=%p)", visitor, obj);
+    if (obj == gDvm.unlinkedJavaLangClass) {
+        assert(obj->obj.clazz == NULL);
+        goto exit;
+    } else {
+        assert(!strcmp(obj->obj.clazz->descriptor, "Ljava/lang/Class;"));
+    }
+    (*visitor)(&obj->obj.clazz);
+    if (IS_CLASS_FLAG_SET(obj, CLASS_ISARRAY)) {
+        (*visitor)(&obj->elementClass);
+    }
+    (*visitor)(&obj->super);
+    (*visitor)(&obj->classLoader);
+    visitInstanceFields(visitor, (Object *)obj);
+    visitStaticFields(visitor, obj);
+    visitInterfaces(visitor, obj);
+exit:
+    LOGV("Exiting visitClassObject(visitor=%p,obj=%p)", visitor, obj);
+}
+
+/*
+ * Visits the class object and, if the array is typed as an object
+ * array, all of the array elements.
+ */
+static void visitArrayObject(Visitor *visitor, Object *obj)
+{
+    assert(visitor != NULL);
+    assert(obj != NULL);
+    assert(obj->clazz != NULL);
+    LOGV("Entering visitArrayObject(visitor=%p,obj=%p)", visitor, obj);
+    (*visitor)(&obj->clazz);
+    if (IS_CLASS_FLAG_SET(obj->clazz, CLASS_ISOBJECTARRAY)) {
+        ArrayObject *array = (ArrayObject *)obj;
+        Object **contents = (Object **)array->contents;
+        size_t i;
+        for (i = 0; i < array->length; ++i) {
+            (*visitor)(&contents[i]);
+        }
+    }
+    LOGV("Exiting visitArrayObject(visitor=%p,obj=%p)", visitor, obj);
+}
+
+/*
+ * Visits the class object and reference typed instance fields of a
+ * data object.
+ */
+static void visitDataObject(Visitor *visitor, Object *obj)
+{
+    assert(visitor != NULL);
+    assert(obj != NULL);
+    assert(obj->clazz != NULL);
+    LOGV("Entering visitDataObject(visitor=%p,obj=%p)", visitor, obj);
+    (*visitor)(&obj->clazz);
+    visitInstanceFields(visitor, obj);
+    if (IS_CLASS_FLAG_SET(obj->clazz, CLASS_ISREFERENCE)) {
+        size_t offset = gDvm.offJavaLangRefReference_referent;
+        Object **ref = BYTE_OFFSET(obj, offset);
+        (*visitor)(ref);
+    }
+    LOGV("Exiting visitDataObject(visitor=%p,obj=%p)", visitor, obj);
+}
+
+/*
+ * Visits all of the reference stored in an object.
+ */
+void dvmVisitObject(Visitor *visitor, Object *obj)
+{
+    assert(visitor != NULL);
+    assert(obj != NULL);
+    LOGV("Entering dvmVisitObject(visitor=%p,obj=%p)", visitor, obj);
+    if (obj == (Object *)gDvm.unlinkedJavaLangClass ||
+        obj->clazz == gDvm.classJavaLangClass) {
+        visitClassObject(visitor, (ClassObject *)obj);
+    } else {
+        assert(obj->clazz != NULL);
+        if (IS_CLASS_FLAG_SET(obj->clazz, CLASS_ISARRAY)) {
+            visitArrayObject(visitor, obj);
+        } else {
+            visitDataObject(visitor, obj);
+        }
+    }
+    LOGV("Exiting dvmVisitObject(visitor=%p,obj=%p)", visitor, obj);
+}
diff --git a/vm/alloc/Visit.h b/vm/alloc/Visit.h
new file mode 100644
index 0000000..5bc9b60
--- /dev/null
+++ b/vm/alloc/Visit.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _DALVIK_ALLOC_VISIT
+#define _DALVIK_ALLOC_VISIT
+
+#include "Dalvik.h"
+
+typedef void Visitor(void *obj);
+
+void dvmVisitObject(Visitor *visitor, Object *obj);
+
+#endif /* _DALVIK_ALLOC_VISIT */