Work on heap and String management

src/exec/ldc.c

@@ -45,8 +45,14 @@ void do_LDC(Thread *thread) {
             break;
         }
         case CONSTANTPOOL_STRING: {
-            // A reference to a String instance should be put onto the stack
-            value->data.ptr = item->Data; /* Pointer to a CONSTANT_STRING_INFO structure */
+            /* A reference to a String instance should be put onto the stack */
+            uint16_t stridx = ((struct CONSTANT_STRING_INFO*)item->Data)->StringIndex;
+            uint16_t strlen = ((struct CONSTANT_UTF8_INFO*)&frame->constants[stridx - 1])->Length;
+            char* strtext = ((struct CONSTANT_UTF8_INFO*)&frame->constants[stridx - 1])->Text;
+
+
+
+            value->data.ptr = NULL;
             dbgmsg("Not implemented");
             exit(-10);
             break;

src/heap.c

@@ -16,3 +16,17 @@
  */
 
 #include <vm.h>
+
+extern VM* vm;
+
+/**
+ * @brief Creates a new Object on the heap, registers it with the GC and 
+ *        returns a pointer to it.
+ * 
+ * @param clazz 
+ * @return Object* 
+ */
+Object* Heap_newObject(const Class* clazz)
+{
+    Object* str = (Object*)malloc(sizeof(Object));
+}

src/include/heap.h

@@ -0,0 +1,26 @@
+/*
+ *  Bean Java VM
+ *  Copyright (C) 2005-2023 Christian Lins <christian@lins.me>
+ *
+ *  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 _HEAP_H_
+#define _HEAP_H_
+
+#include <class.h>
+#include <object.h>
+
+Object* Heap_newObject(const Class* clazz);
+
+#endif

src/include/javastring.h

@@ -0,0 +1,25 @@
+/*
+ *  Bean Java VM
+ *  Copyright (C) 2005-2023 Christian Lins <christian@lins.me>
+ *
+ *  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 _JAVASTRING_H_
+#define _JAVASTRING_H_
+
+#include <object.h>
+
+Object* String_new(const uint16_t len, const char* text);
+
+#endif

src/include/object.h

@@ -29,6 +29,12 @@ typedef struct Object {
 
     Varframe* fields;
     uint16_t  fields_num;
+
+    /* Fields necessary for heap and gc management */
+    bool gc_marked;
+    Object* next;
 } Object;
 
+Object* Object_new(const Class* clazz);
+
 #endif

src/include/vm.h

@@ -26,9 +26,10 @@
 
 #include <thread.h>
 #include <class.h>
+#include <classloader.h>
 #include <debug.h>
+#include <object.h>
 #include <stackframe.h>
-#include <classloader.h>
 #include <linker.h>
 
 #define isAccessFlag(method, accFlag) \
@@ -73,8 +74,8 @@ typedef struct VM {
     unsigned char ThreadNum;
     struct MONITOR* Monitors; /* Monitors */
 
-    unsigned int* MemoryHeap; /* Array of int (pointern) representing the
-                                          GC-Heap of the application. */
+    Object* heapHead;  /* Head of the linked list representing the heap */
+
     bool DoCollectGarbage; /* This is true if the Garbage Collector must
                                           be called. */
 } VM;

src/javastring.c

@@ -0,0 +1,29 @@
+/*
+ *  Bean Java VM
+ *  Copyright (C) 2005-2023 Christian Lins <christian@lins.me>
+ *
+ *  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 <assert.h>
+
+#include <javastring.h>
+
+Object* String_new(const uint16_t len, const char* text)
+{
+    /* Ensure the String class is loaded */
+    Class* clazz = Classloader_forName("java/lang/String");
+    assert(clazz != NULL);
+
+
+}

src/object.c

@@ -0,0 +1,25 @@
+/*
+ *  Bean Java VM
+ *  Copyright (C) 2005-2015 Christian Lins <christian@lins.me>
+ *
+ *  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 <class.h>
+#include <heap.h>
+#include <object.h>
+
+Object* Object_new(const Class* clazz)
+{
+    return Heap_newObject(clazz);
+}

src/thread.c

@@ -94,7 +94,7 @@ int start_process(Class* new_class)
     if (clinitMethod == NULL) {
         dbgmsg("No class constructor found. Continue with main.");
     } else {
-        // Invoke class constructor using special INVOKE instruction
+        /* Invoke class constructor using special INVOKE instruction */
         dbgmsg("Invoke <clinit>");
         Stackframe_create_init_push(&(vm->Threads[0]), new_class, clinitMethod);
     }