startjvm.c

Nucleus_2_kvm_Hello 是kvm移植到Nucleus系统的源代码。。。好东西啊

/*
 * Copyright (c) 1998-2001 Sun Microsystems, Inc. All Rights Reserved.
 *
 * This software is the confidential and proprietary information of Sun
 * Microsystems, Inc. ("Confidential Information").  You shall not
 * disclose such Confidential Information and shall use it only in
 * accordance with the terms of the license agreement you entered into
 * with Sun.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF THE
 * SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 * PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR ANY DAMAGES
 * SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR DISTRIBUTING
 * THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * Use is subject to license terms.
 */

/*=========================================================================
 * KVM
 *=========================================================================
 * SYSTEM:    KVM
 * SUBSYSTEM: Main Java program
 * FILE:      StartJVM.c
 * OVERVIEW:  System initialization and start of JVM
 * AUTHOR:    Antero Taivalsaari, Sun Labs
 *            Edited by Doug Simon 11/1998
 *            Frank Yellin
 *            Bill Pittore (Java-level debugging)
 *=======================================================================*/

/*=========================================================================
 * Include files
 *=======================================================================*/

#include "global.h"

/*=========================================================================
 * Functions
 *=======================================================================*/

/*=========================================================================
 * FUNCTION:      readCommandLineArguments()
 * TYPE:          constructor (kind of)
 * OVERVIEW:      Read the extra command line arguments provided
 *                by the user and construct a string array containing
 *                the arguments. Note: before executing 'main' the
 *                string array must be pushed onto the operand stack.
 * INTERFACE:
 *   parameters:  command line parameters
 *   returns:     string array containing the command line arguments
 *=======================================================================*/

static ARRAY
readCommandLineArguments(int argc, char* argv[])
{
    /*  Get the number of command line arguments */
    ARRAY_CLASS arrayClass = getArrayClass(1, JavaLangString, 0);
    ARRAY stringArray;
    int numberOfArguments = argc;
    int argCount = (numberOfArguments > 0) ? numberOfArguments : 0;
    int i;

    /*  Create a string array for the arguments */
    START_TEMPORARY_ROOTS
        IS_TEMPORARY_ROOT(stringArray, instantiateArray(arrayClass, argCount));
        for (i = 0; i < numberOfArguments; i++) {
            stringArray->data[i].cellp =
                (cell *)instantiateString(argv[i], strlen(argv[i]));
        }
    END_TEMPORARY_ROOTS
    return stringArray;
}

/*=========================================================================
 * FUNCTION:      loadMainClass()
 * TYPE:          private operation
 * OVERVIEW:      The main class is loaded in a slightly different
 *                way than the other classes.  We need to make sure
 *                that the given main class is not an array class.
 *                Also, we need to replace all the '.' characters
 *                in the class name with '/' characters.
 * INTERFACE:
 *   parameters:  class name
 *   returns:     the main class
 *=======================================================================*/

static INSTANCE_CLASS
loadMainClass(char* className)
{
    /* Make sure this is not an array class */
    if (*className == '[') return NULL;

    /* Replace all the '.' characters in the class name with '/' chars */
    replaceLetters(className, '.', '/');

    return (INSTANCE_CLASS)getClass(className);
}

/*=========================================================================
 * FUNCTION:      KVM_Start
 * TYPE:          private operation
 * OVERVIEW:      Initialize everything.  This operation is called
 *                when the VM is launched.
 * INTERFACE:
 *   parameters:  command line parameters
 *   returns:     zero if everything went well, non-zero otherwise
 *=======================================================================*/

int KVM_Start(int argc, char* argv[])
{
    INSTANCE_CLASS mainClass;
    volatile int returnValue = 0; /* Needed to make compiler happy */

    ERROR_TRY {
        /* If ROMIZING and RELOCATABLE_ROM */
        //CreateROMImage();//空的

#if ASYNCHRONOUS_NATIVE_FUNCTIONS
        /* Initialize asynchronous I/O system */
        InitalizeAsynchronousIO();
#endif

        /* Initialize all the essential runtime structures of the VM */
        InitializeNativeCode();


        //InitializeVM();//空的

        /* Initialize global variables */
        //InitializeGlobals();//空函数

        /* Initialize profiling variables */
        //InitializeProfiling();//空的

        /* Initialize the memory system */
        InitializeMemoryManagement();

        /* Initialize internal hash tables */
    //    InitializeHashtables();

        /* Initialize inline caching structures */
        InitializeInlineCaching();

        /* Initialize the class loading interface */
        InitializeClassLoading();

        /* Load and initialize the Java system classes needed by the VM */
        InitializeJavaSystemClasses();

        /* Initialize the class file verifier */
        //InitializeVerifier();

        /* Initialize the event handling system */
        InitializeEvents();

        /* Load the main application class */
        mainClass = loadMainClass(argv[0]);
        if (!mainClass) {
            sprintf(str_buffer, KVM_MSG_CLASS_NOT_FOUND_1STRPARAM, argv[0]);
            AlertUser(str_buffer);
            returnValue = 1;
        } else {

            /* Parse command line arguments */
            ARRAY arguments = readCommandLineArguments(argc - 1, argv + 1);

            /* Now that we have a main class, initialize */
            /* the multithreading system */
            InitializeThreading(mainClass, arguments);

            /* Instances of these classes may have been created without
             * explicitly executing the "new" instruction. Thus we have
             * to make sure they are initialized.
             */
#if ENABLE_JAVA_DEBUGGER
            /* Prepare the VM for Java-level debugging */
            if (debuggerActive) {
                InitDebugger();
            }
#endif
            /* These are pushed onto the stack.  So JavaLangClass is
             * the first class that is initialized.
             */
            initializeClass(JavaLangOutOfMemoryError);
            initializeClass(JavaLangSystem);
            initializeClass(JavaLangString);
            initializeClass(JavaLangThread);
            initializeClass(JavaLangClass);

#if ENABLE_JAVA_DEBUGGER
            /* Prepare the VM for Java-level debugging */
            if (vmDebugReady) {
                setEvent_VMInit();
                if (CurrentThread == NIL) {
                    CurrentThread = removeFirstRunnableThread();
                    /* make sure xp_globals are synched with thread data */
                    loadExecutionEnvironment(CurrentThread);
                }
                sendAllClassPrepares();
            }
#endif /* ENABLE_JAVA_DEBUGGER */

            /* Start the interpreter */
            Interpret();
        }
    } ERROR_CATCH (error) {
        returnValue = error;
    } ERROR_END_CATCH

    return returnValue;
	/*
	1.从 main (int argc, char* argv[])开始 
分析argv，如果在命令行中包含了java堆的大小，则保存堆大小；随后从命令行获取类路径（即要运行的class路径）。 
2.调用StartJVM(argc, argv)函数，开始kvm的运行。 
虚拟机对运行中的错误处理采用了下面的方式： 
ERROR_TRY { 
虚拟机运行代码； 
}ERROR_CATCH(error) { 
错误处理代码； 
}ERROR_END_CATCH 
在虚拟机运行代码出现任何运行期异常时都会调用ERROR_THROW函数（在GLOBAL.H定义），ERROR_THROW将跳转到错误处理代码部分,由错误处理代码决定虚拟机的走向。 
以下函数都属于"虚拟机运行代码"部分： 
(1).CreateROMImage() 
这个函数主要是为了加快KVM启动的速度，在解析指令之前载入JAVA的系统类库。 
要执行这个函数必须先定义了ROMIZING以及RELOCATABLE_ROM这两个宏，这都是 
允许预载入的选项，后一个是表示可以重新载入系统类。一般我们可以不选这两 
个宏（将其定义为0即可） 
(2).#if ASYNCHRONOUS_NATIVE_FUNCTIONS 
// Initialize asynchronous I/O system // 
InitalizeAsynchronousIO();//在虚拟机启动以前要保IOCB(I/O控制块)为空，如果#endif //有其他的I/O活动，虚拟机等待这个线程结束 
 
syhnjs
 发表时间：2004-3-15 16:32:33　　　第1楼 
--------------------------------------------------------------------------------
(3).InitializeNativeCode();//初始化Native方法，与具体平台有关的函数，在 
vmextra目录下有这个函数 
(4).InitializeVM();//初始化虚拟机的运行期数据 
(5).InitializeGlobals();初始化所有的全局变量 
(6).InitializeMemoryManagement()//初始化内存管理单元；创建java堆以及虚拟机 
内存块链表的头指针 
(7).InitializeHashtables()//调用createHashTable(HASHTABLE *tablePtr, int 
bucketCount)创建哈西表到指针tablePtr所指的位 
置，bucketCount是指哈西表所应占的kvm内存块数目 
(8).InitializeInlineCaching()//初始化内嵌缓冲（为了加速虚拟机指令的查找开辟 
的内存区域）。 
(9).InitializeClassLoading()//根据命令行的classpath参数，设置类载入器，（此 
函数与平台有关） 
(10).InitializeJavaSystemClasses()//载入系统类 
(11).InitializeVerifier()//初始化字节码检验器 
(12).InitializeEvents()//初始化虚拟机线程事务系统 
(13).mainClass = (INSTANCE_CLASS)getClass(replaceLetters(argv[0], '.', '/')) 
//得到main方法 
(14).ARRAY arguments = readCommandLineArguments(argc - 1, argv + 1) 
//获取命令行的参数 
(15).InitializeThreading(mainClass, arguments)//准备运行 
(16).initializeClass(JavaLangOutOfMemoryError); 
//初始化相应的系统类 
initializeClass(JavaLangSystem); 
initializeClass(JavaLangString); 
initializeClass(JavaLangThread); 
initializeClass(JavaLangClass); 
(17).Interpret()//开始解释 
 

	*/
}

/*=========================================================================
 * FUNCTION:      KVM_Cleanup
 * TYPE:          private operation
 * OVERVIEW:      Clean up everything.  This operation is called
 *                when the VM is shut down.
 * INTERFACE:
 *   parameters:  <none>
 *   returns:     <nothing>
 *=======================================================================*/

void KVM_Cleanup()
{
#if ENABLE_JAVA_DEBUGGER
    if (vmDebugReady) {
        setEvent_VMDeath();
        CloseDebugger();
        clearAllBreakpoints();
    }
#endif
    //FinalizeVM();
    FinalizeInlineCaching();
    FinalizeNativeCode();
    FinalizeJavaSystemClasses();
    FinalizeClassLoading();
    FinalizeMemoryManagement();
    DestroyROMImage();
    FinalizeHashtables();
}

/*=========================================================================
 * FUNCTION:      StartJVM
 * TYPE:          public global operation
 * OVERVIEW:      Boots up the virtual machine and executes 'main'.
 * INTERFACE:
 *   parameters:  command line arguments
 *   returns:     zero if everything went fine, non-zero otherwise.
 *=======================================================================*/

int StartJVM(int argc, char* argv[])
{
    volatile int returnValue = 0;

    /* Ensure that we have a class to run */
    if (argc <= 0 || argv[0] == NULL) {
        AlertUser(KVM_MSG_MUST_PROVIDE_CLASS_NAME);
        return -1;
    }

    returnValue = KVM_Start(argc, argv);
    KVM_Cleanup();
    return returnValue;
}