从Zygote的启动开始看代码

从Zygote的启动开始看代码


####app_process
/frameworks/base/cmds/app_process/app_main.cpp

int main(int argc, const char* const argv[])
{
    // These are global variables in ProcessState.cpp
    mArgC = argc;
    mArgV = argv;

    mArgLen = 0;
    for (int i=0; i<argc; i++) {
        mArgLen += strlen(argv[i]) + 1;
    }
    mArgLen--;

    AppRuntime runtime;
    const char* argv0 = argv[0];

    // Process command line arguments
    // ignore argv[0]
    argc--;
    argv++;

    // Everything up to '--' or first non '-' arg goes to the vm

    int i = runtime.addVmArguments(argc, argv);

    // Parse runtime arguments.  Stop at first unrecognized option.
    bool zygote = false;
    bool startSystemServer = false;
    bool application = false;
    const char* parentDir = NULL;
    const char* niceName = NULL;
    const char* className = NULL;
    while (i < argc) {
        const char* arg = argv[i++];
        if (!parentDir) {
            parentDir = arg;
        } else if (strcmp(arg, "--zygote") == 0) {
            zygote = true;
            niceName = "zygote";
        } else if (strcmp(arg, "--start-system-server") == 0) {
            startSystemServer = true;
        } else if (strcmp(arg, "--application") == 0) {
            application = true;
        } else if (strncmp(arg, "--nice-name=", 12) == 0) {
            niceName = arg + 12;
        } else {
            className = arg;
            break;
        }
    }

    if (niceName && *niceName) {
        setArgv0(argv0, niceName);
        set_process_name(niceName);
    }

    runtime.mParentDir = parentDir;

    if (zygote) {
        runtime.start("com.android.internal.os.ZygoteInit",
                startSystemServer ? "start-system-server" : "");
    } else if (className) {
        // Remainder of args get passed to startup class main()
        runtime.mClassName = className;
        runtime.mArgC = argc - i;
        runtime.mArgV = argv + i;
        runtime.start("com.android.internal.os.RuntimeInit",
                application ? "application" : "tool");
    } else {
        fprintf(stderr, "Error: no class name or --zygote supplied.\n");
        app_usage();
        LOG_ALWAYS_FATAL("app_process: no class name or --zygote supplied.");
        return 10;
    }
}

//
runtime.start("com.android.internal.os.ZygoteInit", startSystemServer ? "start-system-server" : "");
其中startSystemServer 由init.rc指定，在目录system\core\rootdir中的init.rc.

   service zygote /system/bin/app_process -Xzygote /system/bin --zygote --start-system-server
    class main
    socket zygote stream 660 root system
    onrestart write /sys/android_power/request_state wake
    onrestart write /sys/power/state on
    onrestart restart media
    onrestart restart netd

 

代码进入到base/core/jni/AndroidRuntime.cpp里面。


/*
 * Start the Android runtime.  This involves starting the virtual machine
 * and calling the "static void main(String[] args)" method in the class
 * named by "className".
 *
 * Passes the main function two arguments, the class name and the specified
 * options string.
 */
void AndroidRuntime::start(const char* className, const char* options)
{
    LOGD("\n>>>>>> AndroidRuntime START %s <<<<<<\n",
            className != NULL ? className : "(unknown)");

    blockSigpipe();

    /*
     * 'startSystemServer == true' means runtime is obsolete and not run from
     * init.rc anymore, so we print out the boot start event here.
     */
    if (strcmp(options, "start-system-server") == 0) {
        /* track our progress through the boot sequence */
        const int LOG_BOOT_PROGRESS_START = 3000;
        LOG_EVENT_LONG(LOG_BOOT_PROGRESS_START,
                       ns2ms(systemTime(SYSTEM_TIME_MONOTONIC)));
    }

    const char* rootDir = getenv("ANDROID_ROOT");
    if (rootDir == NULL) {
        rootDir = "/system";
        if (!hasDir("/system")) {
            LOG_FATAL("No root directory specified, and /android does not exist.");
            return;
        }
        setenv("ANDROID_ROOT", rootDir, 1);
    }

    //const char* kernelHack = getenv("LD_ASSUME_KERNEL");
    //LOGD("Found LD_ASSUME_KERNEL='%s'\n", kernelHack);

    /* start the virtual machine */
    JNIEnv* env;
    if (startVm(&mJavaVM, &env) != 0) {
        return;
    }
    onVmCreated(env);

    /*
     * Register android functions.
     */
    if (startReg(env) < 0) {
        LOGE("Unable to register all android natives\n");
        return;
    }

    /*
     * We want to call main() with a String array with arguments in it.
     * At present we have two arguments, the class name and an option string.
     * Create an array to hold them.
     */
    jclass stringClass;
    jobjectArray strArray;
    jstring classNameStr;
    jstring optionsStr;

    stringClass = env->FindClass("java/lang/String");
    assert(stringClass != NULL);
    strArray = env->NewObjectArray(2, stringClass, NULL);
    assert(strArray != NULL);
    classNameStr = env->NewStringUTF(className);
    assert(classNameStr != NULL);
    env->SetObjectArrayElement(strArray, 0, classNameStr);
    optionsStr = env->NewStringUTF(options);
    env->SetObjectArrayElement(strArray, 1, optionsStr);

    /*
     * Start VM.  This thread becomes the main thread of the VM, and will
     * not return until the VM exits.
     */
    char* slashClassName = toSlashClassName(className);
    jclass startClass = env->FindClass(slashClassName);
    if (startClass == NULL) {
        LOGE("JavaVM unable to locate class '%s'\n", slashClassName);
        /* keep going */
    } else {
        jmethodID startMeth = env->GetStaticMethodID(startClass, "main",
            "([Ljava/lang/String;)V");
        if (startMeth == NULL) {
            LOGE("JavaVM unable to find main() in '%s'\n", className);
            /* keep going */
        } else {
            env->CallStaticVoidMethod(startClass, startMeth, strArray);

#if 0
            if (env->ExceptionCheck())
                threadExitUncaughtException(env);
#endif
        }
    }
    free(slashClassName);

    LOGD("Shutting down VM\n");
    if (mJavaVM->DetachCurrentThread() != JNI_OK)
        LOGW("Warning: unable to detach main thread\n");
    if (mJavaVM->DestroyJavaVM() != 0)
        LOGW("Warning: VM did not shut down cleanly\n");
}

//init.rc 已经建立global 环境
# setup the global environment
    export PATH /sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin
    export LD_LIBRARY_PATH /vendor/lib:/system/lib
    export ANDROID_BOOTLOGO 1
    export ANDROID_ROOT /system
    export ANDROID_ASSETS /system/app
    export ANDROID_DATA /data
    export ASEC_MOUNTPOINT /mnt/asec
    export LOOP_MOUNTPOINT /mnt/obb
    export BOOTCLASSPATH /system/framework/core.jar:/system/framework/core-junit.jar:/system/framework/bouncycastle.jar:/system/framework/ext.jar:/system/framework/framework.jar:/system/framework/android.policy.jar:/system/framework/services.jar:/system/framework/apache-xml.jar:/system/framework/filterfw.jar
 

 
 //start vm
/*
 * Start the Dalvik Virtual Machine.
 *
 * Various arguments, most determined by system properties, are passed in.
 * The "mOptions" vector is updated.
 *
 * Returns 0 on success.
 */
int AndroidRuntime::startVm(JavaVM** pJavaVM, JNIEnv** pEnv)
{
    int result = -1;
    JavaVMInitArgs initArgs;
    JavaVMOption opt;
    char propBuf[PROPERTY_VALUE_MAX];
    char stackTraceFileBuf[PROPERTY_VALUE_MAX];
    char dexoptFlagsBuf[PROPERTY_VALUE_MAX];
    char enableAssertBuf[sizeof("-ea:")-1 + PROPERTY_VALUE_MAX];
    char jniOptsBuf[sizeof("-Xjniopts:")-1 + PROPERTY_VALUE_MAX];
    char heapstartsizeOptsBuf[sizeof("-Xms")-1 + PROPERTY_VALUE_MAX];
    char heapsizeOptsBuf[sizeof("-Xmx")-1 + PROPERTY_VALUE_MAX];
    char heapgrowthlimitOptsBuf[sizeof("-XX:HeapGrowthLimit=")-1 + PROPERTY_VALUE_MAX];
    char extraOptsBuf[PROPERTY_VALUE_MAX];
    char* stackTraceFile = NULL;
    bool checkJni = false;
    bool checkDexSum = false;
    bool logStdio = false;
    enum {
      kEMDefault,
      kEMIntPortable,
      kEMIntFast,
#if defined(WITH_JIT)
      kEMJitCompiler,
#endif
    } executionMode = kEMDefault;


    property_get("dalvik.vm.checkjni", propBuf, "");
    if (strcmp(propBuf, "true") == 0) {
        checkJni = true;
    } else if (strcmp(propBuf, "false") != 0) {
        /* property is neither true nor false; fall back on kernel parameter */
        property_get("ro.kernel.android.checkjni", propBuf, "");
        if (propBuf[0] == '1') {
            checkJni = true;
        }
    }

    property_get("dalvik.vm.execution-mode", propBuf, "");
    if (strcmp(propBuf, "int:portable") == 0) {
        executionMode = kEMIntPortable;
    } else if (strcmp(propBuf, "int:fast") == 0) {
        executionMode = kEMIntFast;
#if defined(WITH_JIT)
    } else if (strcmp(propBuf, "int:jit") == 0) {
        executionMode = kEMJitCompiler;
#endif
    }

    property_get("dalvik.vm.stack-trace-file", stackTraceFileBuf, "");

    property_get("dalvik.vm.check-dex-sum", propBuf, "");
    if (strcmp(propBuf, "true") == 0) {
        checkDexSum = true;
    }

    property_get("log.redirect-stdio", propBuf, "");
    if (strcmp(propBuf, "true") == 0) {
        logStdio = true;
    }

    strcpy(enableAssertBuf, "-ea:");
    property_get("dalvik.vm.enableassertions", enableAssertBuf+4, "");

    strcpy(jniOptsBuf, "-Xjniopts:");
    property_get("dalvik.vm.jniopts", jniOptsBuf+10, "");

    /* route exit() to our handler */
    opt.extraInfo = (void*) runtime_exit;
    opt.optionString = "exit";
    mOptions.add(opt);

    /* route fprintf() to our handler */
    opt.extraInfo = (void*) runtime_vfprintf;
    opt.optionString = "vfprintf";
    mOptions.add(opt);

    /* register the framework-specific "is sensitive thread" hook */
    opt.extraInfo = (void*) runtime_isSensitiveThread;
    opt.optionString = "sensitiveThread";
    mOptions.add(opt);

    opt.extraInfo = NULL;

    /* enable verbose; standard options are { jni, gc, class } */
    //options[curOpt++].optionString = "-verbose:jni";
    opt.optionString = "-verbose:gc";
    mOptions.add(opt);
    //options[curOpt++].optionString = "-verbose:class";

    /*
     * The default starting and maximum size of the heap.  Larger
     * values should be specified in a product property override.
     */
    strcpy(heapstartsizeOptsBuf, "-Xms");
    property_get("dalvik.vm.heapstartsize", heapstartsizeOptsBuf+4, "4m");
    opt.optionString = heapstartsizeOptsBuf;
    mOptions.add(opt);
    strcpy(heapsizeOptsBuf, "-Xmx");
    property_get("dalvik.vm.heapsize", heapsizeOptsBuf+4, "16m");
    opt.optionString = heapsizeOptsBuf;
    mOptions.add(opt);

    // Increase the main thread's interpreter stack size for bug 6315322.
    opt.optionString = "-XX:mainThreadStackSize=24K";
    mOptions.add(opt);

    strcpy(heapgrowthlimitOptsBuf, "-XX:HeapGrowthLimit=");
    property_get("dalvik.vm.heapgrowthlimit", heapgrowthlimitOptsBuf+20, "");
    if (heapgrowthlimitOptsBuf[20] != '\0') {
        opt.optionString = heapgrowthlimitOptsBuf;
        mOptions.add(opt);
    }

    /*
     * Enable or disable dexopt features, such as bytecode verification and
     * calculation of register maps for precise GC.
     */
    property_get("dalvik.vm.dexopt-flags", dexoptFlagsBuf, "");
    if (dexoptFlagsBuf[0] != '\0') {
        const char* opc;
        const char* val;

        opc = strstr(dexoptFlagsBuf, "v=");     /* verification */
        if (opc != NULL) {
            switch (*(opc+2)) {
            case 'n':   val = "-Xverify:none";      break;
            case 'r':   val = "-Xverify:remote";    break;
            case 'a':   val = "-Xverify:all";       break;
            default:    val = NULL;                 break;
            }

            if (val != NULL) {
                opt.optionString = val;
                mOptions.add(opt);
            }
        }

        opc = strstr(dexoptFlagsBuf, "o=");     /* optimization */
        if (opc != NULL) {
            switch (*(opc+2)) {
            case 'n':   val = "-Xdexopt:none";      break;
            case 'v':   val = "-Xdexopt:verified";  break;
            case 'a':   val = "-Xdexopt:all";       break;
            case 'f':   val = "-Xdexopt:full";      break;
            default:    val = NULL;                 break;
            }

            if (val != NULL) {
                opt.optionString = val;
                mOptions.add(opt);
            }
        }

        opc = strstr(dexoptFlagsBuf, "m=y");    /* register map */
        if (opc != NULL) {
            opt.optionString = "-Xgenregmap";
            mOptions.add(opt);

            /* turn on precise GC while we're at it */
            opt.optionString = "-Xgc:precise";
            mOptions.add(opt);
        }
    }

    /* enable debugging; set suspend=y to pause during VM init */
    /* use android ADB transport */
    opt.optionString =
        "-agentlib:jdwp=transport=dt_android_adb,suspend=n,server=y";
    mOptions.add(opt);

    ALOGD("CheckJNI is %s\n", checkJni ? "ON" : "OFF");
    if (checkJni) {
        /* extended JNI checking */
        opt.optionString = "-Xcheck:jni";
        mOptions.add(opt);

        /* set a cap on JNI global references */
        opt.optionString = "-Xjnigreflimit:2000";
        mOptions.add(opt);

        /* with -Xcheck:jni, this provides a JNI function call trace */
        //opt.optionString = "-verbose:jni";
        //mOptions.add(opt);
    }

    char lockProfThresholdBuf[sizeof("-Xlockprofthreshold:") + sizeof(propBuf)];
    property_get("dalvik.vm.lockprof.threshold", propBuf, "");
    if (strlen(propBuf) > 0) {
      strcpy(lockProfThresholdBuf, "-Xlockprofthreshold:");
      strcat(lockProfThresholdBuf, propBuf);
      opt.optionString = lockProfThresholdBuf;
      mOptions.add(opt);
    }

#if defined(WITH_JIT)
    /* Force interpreter-only mode for selected opcodes. Eg "1-0a,3c,f1-ff" */
    char jitOpBuf[sizeof("-Xjitop:") + PROPERTY_VALUE_MAX];
    property_get("dalvik.vm.jit.op", propBuf, "");
    if (strlen(propBuf) > 0) {
        strcpy(jitOpBuf, "-Xjitop:");
        strcat(jitOpBuf, propBuf);
        opt.optionString = jitOpBuf;
        mOptions.add(opt);
    }

    /* Force interpreter-only mode for selected methods */
    char jitMethodBuf[sizeof("-Xjitmethod:") + PROPERTY_VALUE_MAX];
    property_get("dalvik.vm.jit.method", propBuf, "");
    if (strlen(propBuf) > 0) {
        strcpy(jitMethodBuf, "-Xjitmethod:");
        strcat(jitMethodBuf, propBuf);
        opt.optionString = jitMethodBuf;
        mOptions.add(opt);
    }
#endif

    if (executionMode == kEMIntPortable) {
        opt.optionString = "-Xint:portable";
        mOptions.add(opt);
    } else if (executionMode == kEMIntFast) {
        opt.optionString = "-Xint:fast";
        mOptions.add(opt);
#if defined(WITH_JIT)
    } else if (executionMode == kEMJitCompiler) {
        opt.optionString = "-Xint:jit";
        mOptions.add(opt);
#endif
    }

    if (checkDexSum) {
        /* perform additional DEX checksum tests */
        opt.optionString = "-Xcheckdexsum";
        mOptions.add(opt);
    }

    if (logStdio) {
        /* convert stdout/stderr to log messages */
        opt.optionString = "-Xlog-stdio";
        mOptions.add(opt);
    }

    if (enableAssertBuf[4] != '\0') {
        /* accept "all" to mean "all classes and packages" */
        if (strcmp(enableAssertBuf+4, "all") == 0)
            enableAssertBuf[3] = '\0';
        ALOGI("Assertions enabled: '%s'\n", enableAssertBuf);
        opt.optionString = enableAssertBuf;
        mOptions.add(opt);
    } else {
        ALOGV("Assertions disabled\n");
    }

    if (jniOptsBuf[10] != '\0') {
        ALOGI("JNI options: '%s'\n", jniOptsBuf);
        opt.optionString = jniOptsBuf;
        mOptions.add(opt);
    }

    if (stackTraceFileBuf[0] != '\0') {
        static const char* stfOptName = "-Xstacktracefile:";

        stackTraceFile = (char*) malloc(strlen(stfOptName) +
            strlen(stackTraceFileBuf) +1);
        strcpy(stackTraceFile, stfOptName);
        strcat(stackTraceFile, stackTraceFileBuf);
        opt.optionString = stackTraceFile;
        mOptions.add(opt);
    }

    /* extra options; parse this late so it overrides others */
    property_get("dalvik.vm.extra-opts", extraOptsBuf, "");
    parseExtraOpts(extraOptsBuf);

    /* Set the properties for locale */
    {
        char langOption[sizeof("-Duser.language=") + 3];
        char regionOption[sizeof("-Duser.region=") + 3];
        strcpy(langOption, "-Duser.language=");
        strcpy(regionOption, "-Duser.region=");
        readLocale(langOption, regionOption);
        opt.extraInfo = NULL;
        opt.optionString = langOption;
        mOptions.add(opt);
        opt.optionString = regionOption;
        mOptions.add(opt);
    }

    /*
     * We don't have /tmp on the device, but we often have an SD card.  Apps
     * shouldn't use this, but some test suites might want to exercise it.
     */
    opt.optionString = "-Djava.io.tmpdir=/sdcard";
    mOptions.add(opt);

    initArgs.version = JNI_VERSION_1_4;
    initArgs.options = mOptions.editArray();
    initArgs.nOptions = mOptions.size();
    initArgs.ignoreUnrecognized = JNI_FALSE;

    /*
     * Initialize the VM.
     *
     * The JavaVM* is essentially per-process, and the JNIEnv* is per-thread.
     * If this call succeeds, the VM is ready, and we can start issuing
     * JNI calls.
     */
    if (JNI_CreateJavaVM(pJavaVM, pEnv, &initArgs) < 0) {
        ALOGE("JNI_CreateJavaVM failed\n");
        goto bail;
    }

    result = 0;

bail:
    free(stackTraceFile);
    return result;
}




  能发现JNI_CreateJavaVM 的原型在dalvik/vm/Jni.cpp 可以找到

Cpp代码  

jint JNI_CreateJavaVM(JavaVM** p_vm, JNIEnv** p_env, void* vm_args) {
    const JavaVMInitArgs* args = (JavaVMInitArgs*) vm_args;
    if (args->version < JNI_VERSION_1_2) {
        return JNI_EVERSION;
    }

    // TODO: don't allow creation of multiple VMs -- one per customer for now

    /* zero globals; not strictly necessary the first time a VM is started */
    memset(&gDvm, 0, sizeof(gDvm));

    /*
     * Set up structures for JNIEnv and VM.
     */
    JavaVMExt* pVM = (JavaVMExt*) calloc(1, sizeof(JavaVMExt));
    pVM->funcTable = &gInvokeInterface;
    pVM->envList = NULL;
    dvmInitMutex(&pVM->envListLock);

    UniquePtr<const char*[]> argv(new const char*[args->nOptions]);
    memset(argv.get(), 0, sizeof(char*) * (args->nOptions));

    /*
     * Convert JNI args to argv.
     *
     * We have to pull out vfprintf/exit/abort, because they use the
     * "extraInfo" field to pass function pointer "hooks" in.  We also
     * look for the -Xcheck:jni stuff here.
     */
    int argc = 0;
    for (int i = 0; i < args->nOptions; i++) {
        const char* optStr = args->options[i].optionString;
        if (optStr == NULL) {
            dvmFprintf(stderr, "ERROR: CreateJavaVM failed: argument %d was NULL\n", i);
            return JNI_ERR;
        } else if (strcmp(optStr, "vfprintf") == 0) {
            gDvm.vfprintfHook = (int (*)(FILE *, const char*, va_list))args->options[i].extraInfo;
        } else if (strcmp(optStr, "exit") == 0) {
            gDvm.exitHook = (void (*)(int)) args->options[i].extraInfo;
        } else if (strcmp(optStr, "abort") == 0) {
            gDvm.abortHook = (void (*)(void))args->options[i].extraInfo;
        } else if (strcmp(optStr, "sensitiveThread") == 0) {
            gDvm.isSensitiveThreadHook = (bool (*)(void))args->options[i].extraInfo;
        } else if (strcmp(optStr, "-Xcheck:jni") == 0) {
            gDvmJni.useCheckJni = true;
        } else if (strncmp(optStr, "-Xjniopts:", 10) == 0) {
            char* jniOpts = strdup(optStr + 10);
            size_t jniOptCount = 1;
            for (char* p = jniOpts; *p != 0; ++p) {
                if (*p == ',') {
                    ++jniOptCount;
                    *p = 0;
                }
            }
            char* jniOpt = jniOpts;
            for (size_t i = 0; i < jniOptCount; ++i) {
                if (strcmp(jniOpt, "warnonly") == 0) {
                    gDvmJni.warnOnly = true;
                } else if (strcmp(jniOpt, "forcecopy") == 0) {
                    gDvmJni.forceCopy = true;
                } else if (strcmp(jniOpt, "logThirdPartyJni") == 0) {
                    gDvmJni.logThirdPartyJni = true;
                } else {
                    dvmFprintf(stderr, "ERROR: CreateJavaVM failed: unknown -Xjniopts option '%s'\n",
                            jniOpt);
                    return JNI_ERR;
                }
                jniOpt += strlen(jniOpt) + 1;
            }
            free(jniOpts);
        } else {
            /* regular option */
            argv[argc++] = optStr;
        }
    }

    if (gDvmJni.useCheckJni) {
        dvmUseCheckedJniVm(pVM);
    }

    if (gDvmJni.jniVm != NULL) {
        dvmFprintf(stderr, "ERROR: Dalvik only supports one VM per process\n");
        return JNI_ERR;
    }
    gDvmJni.jniVm = (JavaVM*) pVM;

    /*
     * Create a JNIEnv for the main thread.  We need to have something set up
     * here because some of the class initialization we do when starting
     * up the VM will call into native code.
     */
    JNIEnvExt* pEnv = (JNIEnvExt*) dvmCreateJNIEnv(NULL);

    /* Initialize VM. */
    gDvm.initializing = true;
    std::string status =
            dvmStartup(argc, argv.get(), args->ignoreUnrecognized, (JNIEnv*)pEnv);
    gDvm.initializing = false;

    if (!status.empty()) {
        free(pEnv);
        free(pVM);
        ALOGW("CreateJavaVM failed: %s", status.c_str());
        return JNI_ERR;
    }

    /*
     * Success!  Return stuff to caller.
     */
    dvmChangeStatus(NULL, THREAD_NATIVE);
    *p_env = (JNIEnv*) pEnv;
    *p_vm = (JavaVM*) pVM;
    ALOGV("CreateJavaVM succeeded");
    return JNI_OK;
}
 

  然后调用Jni.cpp create JNI environment.

 

/*
 * Create a new JNIEnv struct and add it to the VM's list.
 *
 * "self" will be NULL for the main thread, since the VM hasn't started
 * yet; the value will be filled in later.
 */
JNIEnv* dvmCreateJNIEnv(Thread* self) {
    JavaVMExt* vm = (JavaVMExt*) gDvmJni.jniVm;

    //if (self != NULL)
    //    LOGI("Ent CreateJNIEnv: threadid=%d %p", self->threadId, self);

    assert(vm != NULL);

    JNIEnvExt* newEnv = (JNIEnvExt*) calloc(1, sizeof(JNIEnvExt));
    newEnv->funcTable = &gNativeInterface;
    if (self != NULL) {
        dvmSetJniEnvThreadId((JNIEnv*) newEnv, self);
        assert(newEnv->envThreadId != 0);
    } else {
        /* make it obvious if we fail to initialize these later */
        newEnv->envThreadId = 0x77777775;
        newEnv->self = (Thread*) 0x77777779;
    }
    if (gDvmJni.useCheckJni) {
        dvmUseCheckedJniEnv(newEnv);
    }

    ScopedPthreadMutexLock lock(&vm->envListLock);

    /* insert at head of list */
    newEnv->next = vm->envList;
    assert(newEnv->prev == NULL);
    if (vm->envList == NULL) {
        // rare, but possible
        vm->envList = newEnv;
    } else {
        vm->envList->prev = newEnv;
    }
    vm->envList = newEnv;

    //if (self != NULL)
    //    LOGI("Xit CreateJNIEnv: threadid=%d %p", self->threadId, self);
    return (JNIEnv*) newEnv;
}
 
让我们看看JNI environment type

struct JavaVMExt;

struct JNIEnvExt {
    const struct JNINativeInterface* funcTable;     /* must be first */

    const struct JNINativeInterface* baseFuncTable;

    u4      envThreadId;
    Thread* self;

    /* if nonzero, we are in a "critical" JNI call */
    int     critical;

    struct JNIEnvExt* prev;
    struct JNIEnvExt* next;
};

struct JavaVMExt {
    const struct JNIInvokeInterface* funcTable;     /* must be first */

    const struct JNIInvokeInterface* baseFuncTable;

    /* head of list of JNIEnvs associated with this VM */
    JNIEnvExt*      envList;
    pthread_mutex_t envListLock;
};


启动dvm 的方法。你能在Jni.cpp 发现启动代码  

 std::string status =
            dvmStartup(argc, argv.get(), args->ignoreUnrecognized, (JNIEnv*)pEnv);

 
 在Dalvik/vm/Init.cpp中
/*
 * VM initialization.  Pass in any options provided on the command line.
 * Do not pass in the class name or the options for the class.
 *
 * Returns 0 on success.
 */
std::string dvmStartup(int argc, const char* const argv[],
        bool ignoreUnrecognized, JNIEnv* pEnv)
{
    ScopedShutdown scopedShutdown;

    assert(gDvm.initializing);

    //init arguments
    ALOGV("VM init args (%d):", argc);
    for (int i = 0; i < argc; i++) {
        ALOGV("  %d: '%s'", i, argv[i]);
    }
    setCommandLineDefaults();

    /*
     * Process the option flags (if any).
     */
    int cc = processOptions(argc, argv, ignoreUnrecognized);
    if (cc != 0) {
        if (cc < 0) {
            dvmFprintf(stderr, "\n");
            usage("dalvikvm");
        }
        return "syntax error";
    }

#if WITH_EXTRA_GC_CHECKS > 1
    /* only "portable" interp has the extra goodies */
    if (gDvm.executionMode != kExecutionModeInterpPortable) {
        ALOGI("Switching to 'portable' interpreter for GC checks");
        gDvm.executionMode = kExecutionModeInterpPortable;
    }
#endif

    /* Configure group scheduling capabilities */
    if (!access("/dev/cpuctl/tasks", F_OK)) {
        ALOGV("Using kernel group scheduling, err: %s", strerror(errno));
        gDvm.kernelGroupScheduling = 1;
    } else {
        ALOGV("Using kernel scheduler policies");
    }

    /* configure signal handling */
    if (!gDvm.reduceSignals)
        blockSignals();

    /* verify system page size */
    if (sysconf(_SC_PAGESIZE) != SYSTEM_PAGE_SIZE) {
        return StringPrintf("expected page size %d, got %d",
                SYSTEM_PAGE_SIZE, (int) sysconf(_SC_PAGESIZE));
    }

    /* mterp setup */
    ALOGV("Using executionMode %d", gDvm.executionMode);
    dvmCheckAsmConstants();

    /*
     * Initialize components.
     */
    if (!dvmAllocTrackerStartup()) {
        return "dvmAllocTrackerStartup failed";
    }
    if (!dvmGcStartup()) {
        return "dvmGcStartup failed";
    }
    if (!dvmThreadStartup()) {
        return "dvmThreadStartup failed";
    }
    if (!dvmInlineNativeStartup()) {
        return "dvmInlineNativeStartup";
    }
    if (!dvmRegisterMapStartup()) {
        return "dvmRegisterMapStartup failed";
    }
    if (!dvmInstanceofStartup()) {
        return "dvmInstanceofStartup failed";
    }
    if (!dvmClassStartup()) {
        return "dvmClassStartup failed";
    }

    /*
     * At this point, the system is guaranteed to be sufficiently
     * initialized that we can look up classes and class members. This
     * call populates the gDvm instance with all the class and member
     * references that the VM wants to use directly.
     */
    if (!dvmFindRequiredClassesAndMembers()) {
        return "dvmFindRequiredClassesAndMembers failed";
    }

    if (!dvmStringInternStartup()) {
        return "dvmStringInternStartup failed";
    }
    if (!dvmNativeStartup()) {
        return "dvmNativeStartup failed";
    }
    if (!dvmInternalNativeStartup()) {
        return "dvmInternalNativeStartup failed";
    }
    if (!dvmJniStartup()) {
        return "dvmJniStartup failed";
    }
    if (!dvmProfilingStartup()) {
        return "dvmProfilingStartup failed";
    }

    /*
     * Create a table of methods for which we will substitute an "inline"
     * version for performance.
     */
    if (!dvmCreateInlineSubsTable()) {
        return "dvmCreateInlineSubsTable failed";
    }

    /*
     * Miscellaneous class library validation.
     */
    if (!dvmValidateBoxClasses()) {
        return "dvmValidateBoxClasses failed";
    }

    /*
     * Do the last bits of Thread struct initialization we need to allow
     * JNI calls to work.
     */
    if (!dvmPrepMainForJni(pEnv)) {
        return "dvmPrepMainForJni failed";
    }

    /*
     * Explicitly initialize java.lang.Class.  This doesn't happen
     * automatically because it's allocated specially (it's an instance
     * of itself).  Must happen before registration of system natives,
     * which make some calls that throw assertions if the classes they
     * operate on aren't initialized.
     */
    if (!dvmInitClass(gDvm.classJavaLangClass)) {
        return "couldn't initialized java.lang.Class";
    }

    /*
     * Register the system native methods, which are registered through JNI.
     */
    if (!registerSystemNatives(pEnv)) {
        return "couldn't register system natives";
    }

    /*
     * Do some "late" initialization for the memory allocator.  This may
     * allocate storage and initialize classes.
     */
    if (!dvmCreateStockExceptions()) {
        return "dvmCreateStockExceptions failed";
    }

    /*
     * At this point, the VM is in a pretty good state.  Finish prep on
     * the main thread (specifically, create a java.lang.Thread object to go
     * along with our Thread struct).  Note we will probably be executing
     * some interpreted class initializer code in here.
     */
    if (!dvmPrepMainThread()) {
        return "dvmPrepMainThread failed";
    }

    /*
     * Make sure we haven't accumulated any tracked references.  The main
     * thread should be starting with a clean slate.
     */
    if (dvmReferenceTableEntries(&dvmThreadSelf()->internalLocalRefTable) != 0)
    {
        ALOGW("Warning: tracked references remain post-initialization");
        dvmDumpReferenceTable(&dvmThreadSelf()->internalLocalRefTable, "MAIN");
    }

    /* general debugging setup */
    if (!dvmDebuggerStartup()) {
        return "dvmDebuggerStartup failed";
    }

    if (!dvmGcStartupClasses()) {
        return "dvmGcStartupClasses failed";
    }

    /*
     * Init for either zygote mode or non-zygote mode.  The key difference
     * is that we don't start any additional threads in Zygote mode.
     */
    if (gDvm.zygote) {
        if (!initZygote()) {
            return "initZygote failed";
        }
    } else {
        if (!dvmInitAfterZygote()) {
            return "dvmInitAfterZygote failed";
        }
    }


#ifndef NDEBUG
    if (!dvmTestHash())
        ALOGE("dvmTestHash FAILED");
    if (false /*noisy!*/ && !dvmTestIndirectRefTable())
        ALOGE("dvmTestIndirectRefTable FAILED");
#endif

    if (dvmCheckException(dvmThreadSelf())) {
        dvmLogExceptionStackTrace();
        return "Exception pending at end of VM initialization";
    }

    scopedShutdown.disarm();
    return "";
}



class ScopedShutdown {
public:
    ScopedShutdown() : armed_(true) {
    }

    ~ScopedShutdown() {
        if (armed_) {
            dvmShutdown();
        }
    }

    void disarm() {
        armed_ = false;
    }

private:
    bool armed_;
};

//set default command line
static void setCommandLineDefaults()
{
    const char* envStr = getenv("CLASSPATH");
    if (envStr != NULL) {
        gDvm.classPathStr = strdup(envStr);
    } else {
        gDvm.classPathStr = strdup(".");
    }
    envStr = getenv("BOOTCLASSPATH");
    if (envStr != NULL) {
        gDvm.bootClassPathStr = strdup(envStr);
    } else {
        gDvm.bootClassPathStr = strdup(".");
    }

    gDvm.properties = new std::vector<std::string>();

    /* Defaults overridden by -Xms and -Xmx.
     * TODO: base these on a system or application-specific default
     */
    gDvm.heapStartingSize = 2 * 1024 * 1024;  // Spec says 16MB; too big for us.
    gDvm.heapMaximumSize = 16 * 1024 * 1024;  // Spec says 75% physical mem
    gDvm.heapGrowthLimit = 0;  // 0 means no growth limit
    gDvm.stackSize = kDefaultStackSize;
    gDvm.mainThreadStackSize = kDefaultStackSize;

    gDvm.concurrentMarkSweep = true;

    /* gDvm.jdwpSuspend = true; */

    /* allowed unless zygote config doesn't allow it */
    gDvm.jdwpAllowed = true;

    /* default verification and optimization modes */
    gDvm.classVerifyMode = VERIFY_MODE_ALL;
    gDvm.dexOptMode = OPTIMIZE_MODE_VERIFIED;
    gDvm.monitorVerification = false;
    gDvm.generateRegisterMaps = true;
    gDvm.registerMapMode = kRegisterMapModeTypePrecise;

    /*
     * Default execution mode.
     *
     * This should probably interact with the mterp code somehow, e.g. if
     * we know we're using the "desktop" build we should probably be
     * using "portable" rather than "fast".
     */
#if defined(WITH_JIT)
    gDvm.executionMode = kExecutionModeJit;
#else
    gDvm.executionMode = kExecutionModeInterpFast;
#endif

    /*
     * SMP support is a compile-time define, but we may want to have
     * dexopt target a differently-configured device.
     */
    gDvm.dexOptForSmp = (ANDROID_SMP != 0);

    /*
     * Default profiler configuration.
     */
    gDvm.profilerClockSource = kProfilerClockSourceDual;
}


// parser and process option
/*
 * Process an argument vector full of options.  Unlike standard C programs,
 * argv[0] does not contain the name of the program.
 *
 * If "ignoreUnrecognized" is set, we ignore options starting with "-X" or "_"
 * that we don't recognize.  Otherwise, we return with an error as soon as
 * we see anything we can't identify.
 *
 * Returns 0 on success, -1 on failure, and 1 for the special case of
 * "-version" where we want to stop without showing an error message.
 */
static int processOptions(int argc, const char* const argv[],
    bool ignoreUnrecognized)
{
    int i;

    ALOGV("VM options (%d):", argc);
    for (i = 0; i < argc; i++)
        ALOGV("  %d: '%s'", i, argv[i]);

    /*
     * Over-allocate AssertionControl array for convenience.  If allocated,
     * the array must be able to hold at least one entry, so that the
     * zygote-time activation can do its business.
     */
    assert(gDvm.assertionCtrl == NULL);
    if (argc > 0) {
        gDvm.assertionCtrl =
            (AssertionControl*) malloc(sizeof(AssertionControl) * argc);
        if (gDvm.assertionCtrl == NULL)
            return -1;
        assert(gDvm.assertionCtrlCount == 0);
    }

    for (i = 0; i < argc; i++) {
        if (strcmp(argv[i], "-help") == 0) {
            /* show usage and stop */
            return -1;

        } else if (strcmp(argv[i], "-version") == 0) {
            /* show version and stop */
            showVersion();
            return 1;
        } else if (strcmp(argv[i], "-showversion") == 0) {
            /* show version and continue */
            showVersion();

        } else if (strcmp(argv[i], "-classpath") == 0 ||
                   strcmp(argv[i], "-cp") == 0)
        {
            /* set classpath */
            if (i == argc-1) {
                dvmFprintf(stderr, "Missing classpath path list\n");
                return -1;
            }
            free(gDvm.classPathStr); /* in case we have compiled-in default */
            gDvm.classPathStr = strdup(argv[++i]);

        } else if (strncmp(argv[i], "-Xbootclasspath:",
                sizeof("-Xbootclasspath:")-1) == 0)
        {
            /* set bootclasspath */
            const char* path = argv[i] + sizeof("-Xbootclasspath:")-1;

            if (*path == '\0') {
                dvmFprintf(stderr, "Missing bootclasspath path list\n");
                return -1;
            }
            free(gDvm.bootClassPathStr);
            gDvm.bootClassPathStr = strdup(path);

        } else if (strncmp(argv[i], "-Xbootclasspath/a:",
                sizeof("-Xbootclasspath/a:")-1) == 0) {
            const char* appPath = argv[i] + sizeof("-Xbootclasspath/a:")-1;

            if (*(appPath) == '\0') {
                dvmFprintf(stderr, "Missing appending bootclasspath path list\n");
                return -1;
            }
            char* allPath;

            if (asprintf(&allPath, "%s:%s", gDvm.bootClassPathStr, appPath) < 0) {
                dvmFprintf(stderr, "Can't append to bootclasspath path list\n");
                return -1;
            }
            free(gDvm.bootClassPathStr);
            gDvm.bootClassPathStr = allPath;

        } else if (strncmp(argv[i], "-Xbootclasspath/p:",
                sizeof("-Xbootclasspath/p:")-1) == 0) {
            const char* prePath = argv[i] + sizeof("-Xbootclasspath/p:")-1;

            if (*(prePath) == '\0') {
                dvmFprintf(stderr, "Missing prepending bootclasspath path list\n");
                return -1;
            }
            char* allPath;

            if (asprintf(&allPath, "%s:%s", prePath, gDvm.bootClassPathStr) < 0) {
                dvmFprintf(stderr, "Can't prepend to bootclasspath path list\n");
                return -1;
            }
            free(gDvm.bootClassPathStr);
            gDvm.bootClassPathStr = allPath;

        } else if (strncmp(argv[i], "-D", 2) == 0) {
            /* Properties are handled in managed code. We just check syntax. */
            if (strchr(argv[i], '=') == NULL) {
                dvmFprintf(stderr, "Bad system property setting: \"%s\"\n",
                    argv[i]);
                return -1;
            }
            gDvm.properties->push_back(argv[i] + 2);

        } else if (strcmp(argv[i], "-jar") == 0) {
            // TODO: handle this; name of jar should be in argv[i+1]
            dvmFprintf(stderr, "-jar not yet handled\n");
            assert(false);

        } else if (strncmp(argv[i], "-Xms", 4) == 0) {
            size_t val = parseMemOption(argv[i]+4, 1024);
            if (val != 0) {
                if (val >= kMinHeapStartSize && val <= kMaxHeapSize) {
                    gDvm.heapStartingSize = val;
                } else {
                    dvmFprintf(stderr,
                        "Invalid -Xms '%s', range is %dKB to %dKB\n",
                        argv[i], kMinHeapStartSize/1024, kMaxHeapSize/1024);
                    return -1;
                }
            } else {
                dvmFprintf(stderr, "Invalid -Xms option '%s'\n", argv[i]);
                return -1;
            }
        } else if (strncmp(argv[i], "-Xmx", 4) == 0) {
            size_t val = parseMemOption(argv[i]+4, 1024);
            if (val != 0) {
                if (val >= kMinHeapSize && val <= kMaxHeapSize) {
                    gDvm.heapMaximumSize = val;
                } else {
                    dvmFprintf(stderr,
                        "Invalid -Xmx '%s', range is %dKB to %dKB\n",
                        argv[i], kMinHeapSize/1024, kMaxHeapSize/1024);
                    return -1;
                }
            } else {
                dvmFprintf(stderr, "Invalid -Xmx option '%s'\n", argv[i]);
                return -1;
            }
        } else if (strncmp(argv[i], "-XX:HeapGrowthLimit=", 20) == 0) {
            size_t val = parseMemOption(argv[i] + 20, 1024);
            if (val != 0) {
                gDvm.heapGrowthLimit = val;
            } else {
                dvmFprintf(stderr, "Invalid -XX:HeapGrowthLimit option '%s'\n", argv[i]);
                return -1;
            }
        } else if (strncmp(argv[i], "-Xss", 4) == 0) {
            size_t val = parseMemOption(argv[i]+4, 1);
            if (val != 0) {
                if (val >= kMinStackSize && val <= kMaxStackSize) {
                    gDvm.stackSize = val;
                    if (val > gDvm.mainThreadStackSize) {
                        gDvm.mainThreadStackSize = val;
                    }
                } else {
                    dvmFprintf(stderr, "Invalid -Xss '%s', range is %d to %d\n",
                        argv[i], kMinStackSize, kMaxStackSize);
                    return -1;
                }
            } else {
                dvmFprintf(stderr, "Invalid -Xss option '%s'\n", argv[i]);
                return -1;
            }

        } else if (strncmp(argv[i], "-XX:mainThreadStackSize=", strlen("-XX:mainThreadStackSize=")) == 0) {
            size_t val = parseMemOption(argv[i] + strlen("-XX:mainThreadStackSize="), 1);
            if (val != 0) {
                if (val >= kMinStackSize && val <= kMaxStackSize) {
                    gDvm.mainThreadStackSize = val;
                } else {
                    dvmFprintf(stderr, "Invalid -XX:mainThreadStackSize '%s', range is %d to %d\n",
                               argv[i], kMinStackSize, kMaxStackSize);
                    return -1;
                }
            } else {
                dvmFprintf(stderr, "Invalid -XX:mainThreadStackSize option '%s'\n", argv[i]);
                return -1;
            }

        } else if (strncmp(argv[i], "-XX:+DisableExplicitGC", 22) == 0) {
            gDvm.disableExplicitGc = true;
        } else if (strcmp(argv[i], "-verbose") == 0 ||
            strcmp(argv[i], "-verbose:class") == 0)
        {
            // JNI spec says "-verbose:gc,class" is valid, but cmd line
            // doesn't work that way; may want to support.
            gDvm.verboseClass = true;
        } else if (strcmp(argv[i], "-verbose:jni") == 0) {
            gDvm.verboseJni = true;
        } else if (strcmp(argv[i], "-verbose:gc") == 0) {
            gDvm.verboseGc = true;
        } else if (strcmp(argv[i], "-verbose:shutdown") == 0) {
            gDvm.verboseShutdown = true;

        } else if (strncmp(argv[i], "-enableassertions", 17) == 0) {
            enableAssertions(argv[i] + 17, true);
        } else if (strncmp(argv[i], "-ea", 3) == 0) {
            enableAssertions(argv[i] + 3, true);
        } else if (strncmp(argv[i], "-disableassertions", 18) == 0) {
            enableAssertions(argv[i] + 18, false);
        } else if (strncmp(argv[i], "-da", 3) == 0) {
            enableAssertions(argv[i] + 3, false);
        } else if (strcmp(argv[i], "-enablesystemassertions") == 0 ||
                   strcmp(argv[i], "-esa") == 0)
        {
            enableAssertions(NULL, true);
        } else if (strcmp(argv[i], "-disablesystemassertions") == 0 ||
                   strcmp(argv[i], "-dsa") == 0)
        {
            enableAssertions(NULL, false);

        } else if (strncmp(argv[i], "-Xcheck:jni", 11) == 0) {
            /* nothing to do now -- was handled during JNI init */

        } else if (strcmp(argv[i], "-Xdebug") == 0) {
            /* accept but ignore */

        } else if (strncmp(argv[i], "-Xrunjdwp:", 10) == 0 ||
            strncmp(argv[i], "-agentlib:jdwp=", 15) == 0)
        {
            const char* tail;

            if (argv[i][1] == 'X')
                tail = argv[i] + 10;
            else
                tail = argv[i] + 15;

            if (strncmp(tail, "help", 4) == 0 || !parseJdwpOptions(tail)) {
                showJdwpHelp();
                return 1;
            }
        } else if (strcmp(argv[i], "-Xrs") == 0) {
            gDvm.reduceSignals = true;
        } else if (strcmp(argv[i], "-Xnoquithandler") == 0) {
            /* disables SIGQUIT handler thread while still blocking SIGQUIT */
            /* (useful if we don't want thread but system still signals us) */
            gDvm.noQuitHandler = true;
        } else if (strcmp(argv[i], "-Xzygote") == 0) {
            gDvm.zygote = true;
#if defined(WITH_JIT)
            gDvmJit.runningInAndroidFramework = true;
#endif
        } else if (strncmp(argv[i], "-Xdexopt:", 9) == 0) {
            if (strcmp(argv[i] + 9, "none") == 0)
                gDvm.dexOptMode = OPTIMIZE_MODE_NONE;
            else if (strcmp(argv[i] + 9, "verified") == 0)
                gDvm.dexOptMode = OPTIMIZE_MODE_VERIFIED;
            else if (strcmp(argv[i] + 9, "all") == 0)
                gDvm.dexOptMode = OPTIMIZE_MODE_ALL;
            else if (strcmp(argv[i] + 9, "full") == 0)
                gDvm.dexOptMode = OPTIMIZE_MODE_FULL;
            else {
                dvmFprintf(stderr, "Unrecognized dexopt option '%s'\n",argv[i]);
                return -1;
            }
        } else if (strncmp(argv[i], "-Xverify:", 9) == 0) {
            if (strcmp(argv[i] + 9, "none") == 0)
                gDvm.classVerifyMode = VERIFY_MODE_NONE;
            else if (strcmp(argv[i] + 9, "remote") == 0)
                gDvm.classVerifyMode = VERIFY_MODE_REMOTE;
            else if (strcmp(argv[i] + 9, "all") == 0)
                gDvm.classVerifyMode = VERIFY_MODE_ALL;
            else {
                dvmFprintf(stderr, "Unrecognized verify option '%s'\n",argv[i]);
                return -1;
            }
        } else if (strncmp(argv[i], "-Xjnigreflimit:", 15) == 0) {
            int lim = atoi(argv[i] + 15);
            if (lim < 200 || (lim % 100) != 0) {
                dvmFprintf(stderr, "Bad value for -Xjnigreflimit: '%s'\n",
                    argv[i]+15);
                return -1;
            }
            gDvm.jniGrefLimit = lim;
        } else if (strncmp(argv[i], "-Xjnitrace:", 11) == 0) {
            gDvm.jniTrace = strdup(argv[i] + 11);
        } else if (strcmp(argv[i], "-Xlog-stdio") == 0) {
            gDvm.logStdio = true;

        } else if (strncmp(argv[i], "-Xint", 5) == 0) {
            if (argv[i][5] == ':') {
                if (strcmp(argv[i] + 6, "portable") == 0)
                    gDvm.executionMode = kExecutionModeInterpPortable;
                else if (strcmp(argv[i] + 6, "fast") == 0)
                    gDvm.executionMode = kExecutionModeInterpFast;
#ifdef WITH_JIT
                else if (strcmp(argv[i] + 6, "jit") == 0)
                    gDvm.executionMode = kExecutionModeJit;
#endif
                else {
                    dvmFprintf(stderr,
                        "Warning: Unrecognized interpreter mode %s\n",argv[i]);
                    /* keep going */
                }
            } else {
                /* disable JIT if it was enabled by default */
                gDvm.executionMode = kExecutionModeInterpFast;
            }

        } else if (strncmp(argv[i], "-Xlockprofthreshold:", 20) == 0) {
            gDvm.lockProfThreshold = atoi(argv[i] + 20);

#ifdef WITH_JIT
        } else if (strncmp(argv[i], "-Xjitop", 7) == 0) {
            processXjitop(argv[i]);
        } else if (strncmp(argv[i], "-Xjitmethod", 11) == 0) {
            processXjitmethod(argv[i]);
        } else if (strncmp(argv[i], "-Xjitblocking", 13) == 0) {
          gDvmJit.blockingMode = true;
        } else if (strncmp(argv[i], "-Xjitthreshold:", 15) == 0) {
          gDvmJit.threshold = atoi(argv[i] + 15);
        } else if (strncmp(argv[i], "-Xincludeselectedop", 19) == 0) {
          gDvmJit.includeSelectedOp = true;
        } else if (strncmp(argv[i], "-Xincludeselectedmethod", 23) == 0) {
          gDvmJit.includeSelectedMethod = true;
        } else if (strncmp(argv[i], "-Xjitcheckcg", 12) == 0) {
          gDvmJit.checkCallGraph = true;
          /* Need to enable blocking mode due to stack crawling */
          gDvmJit.blockingMode = true;
        } else if (strncmp(argv[i], "-Xjitverbose", 12) == 0) {
          gDvmJit.printMe = true;
        } else if (strncmp(argv[i], "-Xjitprofile", 12) == 0) {
          gDvmJit.profileMode = kTraceProfilingContinuous;
        } else if (strncmp(argv[i], "-Xjitdisableopt", 15) == 0) {
          /* Disable selected optimizations */
          if (argv[i][15] == ':') {
              sscanf(argv[i] + 16, "%x", &gDvmJit.disableOpt);
          /* Disable all optimizations */
          } else {
              gDvmJit.disableOpt = -1;
          }
        } else if (strncmp(argv[i], "-Xjitsuspendpoll", 16) == 0) {
          gDvmJit.genSuspendPoll = true;
#endif

        } else if (strncmp(argv[i], "-Xstacktracefile:", 17) == 0) {
            gDvm.stackTraceFile = strdup(argv[i]+17);

        } else if (strcmp(argv[i], "-Xgenregmap") == 0) {
            gDvm.generateRegisterMaps = true;
        } else if (strcmp(argv[i], "-Xnogenregmap") == 0) {
            gDvm.generateRegisterMaps = false;

        } else if (strcmp(argv[i], "Xverifyopt:checkmon") == 0) {
            gDvm.monitorVerification = true;
        } else if (strcmp(argv[i], "Xverifyopt:nocheckmon") == 0) {
            gDvm.monitorVerification = false;

        } else if (strncmp(argv[i], "-Xgc:", 5) == 0) {
            if (strcmp(argv[i] + 5, "precise") == 0)
                gDvm.preciseGc = true;
            else if (strcmp(argv[i] + 5, "noprecise") == 0)
                gDvm.preciseGc = false;
            else if (strcmp(argv[i] + 5, "preverify") == 0)
                gDvm.preVerify = true;
            else if (strcmp(argv[i] + 5, "nopreverify") == 0)
                gDvm.preVerify = false;
            else if (strcmp(argv[i] + 5, "postverify") == 0)
                gDvm.postVerify = true;
            else if (strcmp(argv[i] + 5, "nopostverify") == 0)
                gDvm.postVerify = false;
            else if (strcmp(argv[i] + 5, "concurrent") == 0)
                gDvm.concurrentMarkSweep = true;
            else if (strcmp(argv[i] + 5, "noconcurrent") == 0)
                gDvm.concurrentMarkSweep = false;
            else if (strcmp(argv[i] + 5, "verifycardtable") == 0)
                gDvm.verifyCardTable = true;
            else if (strcmp(argv[i] + 5, "noverifycardtable") == 0)
                gDvm.verifyCardTable = false;
            else {
                dvmFprintf(stderr, "Bad value for -Xgc");
                return -1;
            }
            ALOGV("Precise GC configured %s", gDvm.preciseGc ? "ON" : "OFF");

        } else if (strcmp(argv[i], "-Xcheckdexsum") == 0) {
            gDvm.verifyDexChecksum = true;

        } else if (strcmp(argv[i], "-Xprofile:threadcpuclock") == 0) {
            gDvm.profilerClockSource = kProfilerClockSourceThreadCpu;
        } else if (strcmp(argv[i], "-Xprofile:wallclock") == 0) {
            gDvm.profilerClockSource = kProfilerClockSourceWall;
        } else if (strcmp(argv[i], "-Xprofile:dualclock") == 0) {
            gDvm.profilerClockSource = kProfilerClockSourceDual;

        } else {
            if (!ignoreUnrecognized) {
                dvmFprintf(stderr, "Unrecognized option '%s'\n", argv[i]);
                return -1;
            }
        }
    }

    return 0;
}


vm/alloc/Alloc.cpp
/*
 * Initialize the GC universe.
 *
 * We're currently using a memory-mapped arena to keep things off of the
 * main heap.  This needs to be replaced with something real.
 */
bool dvmGcStartup()
{
    dvmInitMutex(&gDvm.gcHeapLock);
    pthread_cond_init(&gDvm.gcHeapCond, NULL);
    return dvmHeapStartup();
}

//dvm Heap start up

bool dvmHeapStartup()
{
    GcHeap *gcHeap;

    if (gDvm.heapGrowthLimit == 0) {
        gDvm.heapGrowthLimit = gDvm.heapMaximumSize;
    }

    gcHeap = dvmHeapSourceStartup(gDvm.heapStartingSize,
                                  gDvm.heapMaximumSize,
                                  gDvm.heapGrowthLimit);
    if (gcHeap == NULL) {
        return false;
    }
    gcHeap->ddmHpifWhen = 0;
    gcHeap->ddmHpsgWhen = 0;
    gcHeap->ddmHpsgWhat = 0;
    gcHeap->ddmNhsgWhen = 0;
    gcHeap->ddmNhsgWhat = 0;
    gDvm.gcHeap = gcHeap;

    /* Set up the lists we'll use for cleared reference objects.
     */
    gcHeap->clearedReferences = NULL;

    if (!dvmCardTableStartup(gDvm.heapMaximumSize, gDvm.heapGrowthLimit)) {
        LOGE_HEAP("card table startup failed.");
        return false;
    }

    return true;
}


vm/Misc.cpp
/*
 * Initializes the heap source; must be called before any other
 * dvmHeapSource*() functions.  Returns a GcHeap structure
 * allocated from the heap source.
 */
GcHeap* dvmHeapSourceStartup(size_t startSize, size_t maximumSize,
                             size_t growthLimit)
{
    GcHeap *gcHeap;
    HeapSource *hs;
    mspace msp;
    size_t length;
    void *base;

    assert(gHs == NULL);

    if (!(startSize <= growthLimit && growthLimit <= maximumSize)) {
        ALOGE("Bad heap size parameters (start=%zd, max=%zd, limit=%zd)",
             startSize, maximumSize, growthLimit);
        return NULL;
    }

    /*
     * Allocate a contiguous region of virtual memory to subdivided
     * among the heaps managed by the garbage collector.
     */
    length = ALIGN_UP_TO_PAGE_SIZE(maximumSize);
    base = dvmAllocRegion(length, PROT_NONE, "dalvik-heap");
    if (base == NULL) {
        return NULL;
    }

    /* Create an unlocked dlmalloc mspace to use as
     * a heap source.
     */
    msp = createMspace(base, startSize, maximumSize);
    if (msp == NULL) {
        goto fail;
    }

    gcHeap = (GcHeap *)calloc(1, sizeof(*gcHeap));
    if (gcHeap == NULL) {
        LOGE_HEAP("Can't allocate heap descriptor");
        goto fail;
    }

    hs = (HeapSource *)calloc(1, sizeof(*hs));
    if (hs == NULL) {
        LOGE_HEAP("Can't allocate heap source");
        free(gcHeap);
        goto fail;
    }

    hs->targetUtilization = DEFAULT_HEAP_UTILIZATION;
    hs->startSize = startSize;
    hs->maximumSize = maximumSize;
    hs->growthLimit = growthLimit;
    hs->idealSize = startSize;
    hs->softLimit = SIZE_MAX;    // no soft limit at first
    hs->numHeaps = 0;
    hs->sawZygote = gDvm.zygote;
    hs->hasGcThread = false;
    hs->heapBase = (char *)base;
    hs->heapLength = length;
    if (!addInitialHeap(hs, msp, growthLimit)) {
        LOGE_HEAP("Can't add initial heap");
        goto fail;
    }
    if (!dvmHeapBitmapInit(&hs->liveBits, base, length, "dalvik-bitmap-1")) {
        LOGE_HEAP("Can't create liveBits");
        goto fail;
    }
    if (!dvmHeapBitmapInit(&hs->markBits, base, length, "dalvik-bitmap-2")) {
        LOGE_HEAP("Can't create markBits");
        dvmHeapBitmapDelete(&hs->liveBits);
        goto fail;
    }
    if (!allocMarkStack(&gcHeap->markContext.stack, hs->maximumSize)) {
        ALOGE("Can't create markStack");
        dvmHeapBitmapDelete(&hs->markBits);
        dvmHeapBitmapDelete(&hs->liveBits);
        goto fail;
    }
    gcHeap->markContext.bitmap = &hs->markBits;
    gcHeap->heapSource = hs;

    gHs = hs;
    return gcHeap;

fail:
    munmap(base, length);
    return NULL;
}


vm/Misc.cpp
void *dvmAllocRegion(size_t byteCount, int prot, const char *name) {
    void *base;
    int fd, ret;

    byteCount = ALIGN_UP_TO_PAGE_SIZE(byteCount);
    fd = ashmem_create_region(name, byteCount);
    if (fd == -1) {
        return NULL;
    }
    base = mmap(NULL, byteCount, prot, MAP_PRIVATE, fd, 0);
    ret = close(fd);
    if (base == MAP_FAILED) {
        return NULL;
    }
    if (ret == -1) {
        return NULL;
    }
    return base;
}


vm/alloc/HeapSource.cpp
static mspace createMspace(void *base, size_t startSize, size_t maximumSize)
{
    /* Create an unlocked dlmalloc mspace to use as
     * a heap source.
     *
     * We start off reserving startSize / 2 bytes but
     * letting the heap grow to startSize.  This saves
     * memory in the case where a process uses even less
     * than the starting size.
     */
    LOGV_HEAP("Creating VM heap of size %zu", startSize);
    errno = 0;

    mspace msp = create_contiguous_mspace_with_base(startSize/2,
            maximumSize, /*locked=*/false, base);
    if (msp != NULL) {
        /* Don't let the heap grow past the starting size without
         * our intervention.
         */
        mspace_set_max_allowed_footprint(msp, startSize);
    } else {
        /* There's no guarantee that errno has meaning when the call
         * fails, but it often does.
         */
        LOGE_HEAP("Can't create VM heap of size (%zu,%zu): %s",
            startSize/2, maximumSize, strerror(errno));
    }

    return msp;
}

/vm/alloc/CardTable.cpp

*
 * Initializes the card table; must be called before any other
 * dvmCardTable*() functions.
 */
bool dvmCardTableStartup(size_t heapMaximumSize, size_t growthLimit)
{
    size_t length;
    void *allocBase;
    u1 *biasedBase;
    GcHeap *gcHeap = gDvm.gcHeap;
    void *heapBase = dvmHeapSourceGetBase();
    assert(gcHeap != NULL);
    assert(heapBase != NULL);

    /* Set up the card table */
    length = heapMaximumSize / GC_CARD_SIZE;
    /* Allocate an extra 256 bytes to allow fixed low-byte of base */
    allocBase = dvmAllocRegion(length + 0x100, PROT_READ | PROT_WRITE,
                            "dalvik-card-table");
    if (allocBase == NULL) {
        return false;
    }
    gcHeap->cardTableBase = (u1*)allocBase;
    gcHeap->cardTableLength = growthLimit / GC_CARD_SIZE;
    gcHeap->cardTableMaxLength = length;
    gcHeap->cardTableOffset = 0;
    /* All zeros is the correct initial value; all clean. */
    assert(GC_CARD_CLEAN == 0);

    biasedBase = (u1 *)((uintptr_t)allocBase -
                        ((uintptr_t)heapBase >> GC_CARD_SHIFT));
    if (((uintptr_t)biasedBase & 0xff) != GC_CARD_DIRTY) {
        int offset = GC_CARD_DIRTY - ((uintptr_t)biasedBase & 0xff);
        gcHeap->cardTableOffset = offset + (offset < 0 ? 0x100 : 0);
        biasedBase += gcHeap->cardTableOffset;
    }
    assert(((uintptr_t)biasedBase & 0xff) == GC_CARD_DIRTY);
    gDvm.biasedCardTableBase = biasedBase;

    return true;
}


vm/alloc/HeapSource.cpp
void *dvmHeapSourceGetBase()
{
    return gHs->heapBase;
}



/vm/Thread.cpp

/*
 * Initialize thread list and main thread's environment.  We need to set
 * up some basic stuff so that dvmThreadSelf() will work when we start
 * loading classes (e.g. to check for exceptions).
 */
bool dvmThreadStartup()
{
    Thread* thread;

    /* allocate a TLS slot */
    if (pthread_key_create(&gDvm.pthreadKeySelf, threadExitCheck) != 0) {
        ALOGE("ERROR: pthread_key_create failed");
        return false;
    }

    /* test our pthread lib */
    if (pthread_getspecific(gDvm.pthreadKeySelf) != NULL)
        ALOGW("WARNING: newly-created pthread TLS slot is not NULL");

    /* prep thread-related locks and conditions */
    dvmInitMutex(&gDvm.threadListLock);
    pthread_cond_init(&gDvm.threadStartCond, NULL);
    pthread_cond_init(&gDvm.vmExitCond, NULL);
    dvmInitMutex(&gDvm._threadSuspendLock);
    dvmInitMutex(&gDvm.threadSuspendCountLock);
    pthread_cond_init(&gDvm.threadSuspendCountCond, NULL);

    /*
     * Dedicated monitor for Thread.sleep().
     * TODO: change this to an Object* so we don't have to expose this
     * call, and we interact better with JDWP monitor calls.  Requires
     * deferring the object creation to much later (e.g. final "main"
     * thread prep) or until first use.
     */
    gDvm.threadSleepMon = dvmCreateMonitor(NULL);

    gDvm.threadIdMap = dvmAllocBitVector(kMaxThreadId, false);

    thread = allocThread(gDvm.mainThreadStackSize);
    if (thread == NULL)
        return false;

    /* switch mode for when we run initializers */
    thread->status = THREAD_RUNNING;

    /*
     * We need to assign the threadId early so we can lock/notify
     * object monitors.  We'll set the "threadObj" field later.
     */
    prepareThread(thread);
    gDvm.threadList = thread;

#ifdef COUNT_PRECISE_METHODS
    gDvm.preciseMethods = dvmPointerSetAlloc(200);
#endif

    return true;
}


vm/Sync.cpp
/*
 * Create and initialize a monitor.
 */
Monitor* dvmCreateMonitor(Object* obj)
{
    Monitor* mon;

    mon = (Monitor*) calloc(1, sizeof(Monitor));
    if (mon == NULL) {
        ALOGE("Unable to allocate monitor");
        dvmAbort();
    }
    if (((u4)mon & 7) != 0) {
        ALOGE("Misaligned monitor: %p", mon);
        dvmAbort();
    }
    mon->obj = obj;
    dvmInitMutex(&mon->lock);

    /* replace the head of the list with the new monitor */
    do {
        mon->next = gDvm.monitorList;
    } while (android_atomic_release_cas((int32_t)mon->next, (int32_t)mon,
            (int32_t*)(void*)&gDvm.monitorList) != 0);

    return mon;
}

vm/Bitvector.cpp

/*
 * Allocate a bit vector with enough space to hold at least the specified
 * number of bits.
 */
BitVector* dvmAllocBitVector(unsigned int startBits, bool expandable)
{
    BitVector* bv;
    unsigned int count;

    assert(sizeof(bv->storage[0]) == 4);        /* assuming 32-bit units */

    bv = (BitVector*) malloc(sizeof(BitVector));

    count = (startBits + 31) >> 5;

    bv->storageSize = count;
    bv->expandable = expandable;
    bv->storage = (u4*) calloc(count, sizeof(u4));
    return bv;
}


vm/thread.cpp
/*
 * Finish initialization of a Thread struct.
 *
 * This must be called while executing in the new thread, but before the
 * thread is added to the thread list.
 *
 * NOTE: The threadListLock must be held by the caller (needed for
 * assignThreadId()).
 */
static bool prepareThread(Thread* thread)
{
    assignThreadId(thread);
    thread->handle = pthread_self();
    thread->systemTid = dvmGetSysThreadId();

    //ALOGI("SYSTEM TID IS %d (pid is %d)", (int) thread->systemTid,
    //    (int) getpid());
    /*
     * If we were called by dvmAttachCurrentThread, the self value is
     * already correctly established as "thread".
     */
    setThreadSelf(thread);

    ALOGV("threadid=%d: interp stack at %p",
        thread->threadId, thread->interpStackStart - thread->interpStackSize);

    /*
     * Initialize invokeReq.
     */
    dvmInitMutex(&thread->invokeReq.lock);
    pthread_cond_init(&thread->invokeReq.cv, NULL);

    /*
     * Initialize our reference tracking tables.
     *
     * Most threads won't use jniMonitorRefTable, so we clear out the
     * structure but don't call the init function (which allocs storage).
     */
    if (!thread->jniLocalRefTable.init(kJniLocalRefMin,
            kJniLocalRefMax, kIndirectKindLocal)) {
        return false;
    }
    if (!dvmInitReferenceTable(&thread->internalLocalRefTable,
            kInternalRefDefault, kInternalRefMax))
        return false;

    memset(&thread->jniMonitorRefTable, 0, sizeof(thread->jniMonitorRefTable));

    pthread_cond_init(&thread->waitCond, NULL);
    dvmInitMutex(&thread->waitMutex);

    /* Initialize safepoint callback mechanism */
    dvmInitMutex(&thread->callbackMutex);

    return true;
}

vm/inlineNative.cpp
/*
 * Allocate some tables.
 */
bool dvmInlineNativeStartup()
{
    gDvm.inlinedMethods =
        (Method**) calloc(NELEM(gDvmInlineOpsTable), sizeof(Method*));
    if (gDvm.inlinedMethods == NULL)
        return false;

    return true;
}

vm/analysis/RegisterMap.cpp
/*
 * Prepare some things.
 */
bool dvmRegisterMapStartup()
{
#ifdef REGISTER_MAP_STATS
    MapStats* pStats = calloc(1, sizeof(MapStats));
    gDvm.registerMapStats = pStats;
#endif
    return true;
}


vm/oo/TypeCheck.cpp
 * Allocate cache.
 */
bool dvmInstanceofStartup()
{
    gDvm.instanceofCache = dvmAllocAtomicCache(INSTANCEOF_CACHE_SIZE);
    if (gDvm.instanceofCache == NULL)
        return false;
    return true;
}


vm/oo/Class.cpp
/*
 * Initialize the bootstrap class loader.
 *
 * Call this after the bootclasspath string has been finalized.
 */
bool dvmClassStartup()
{
    /* make this a requirement -- don't currently support dirs in path */
    if (strcmp(gDvm.bootClassPathStr, ".") == 0) {
        ALOGE("ERROR: must specify non-'.' bootclasspath");
        return false;
    }

    gDvm.loadedClasses =
        dvmHashTableCreate(256, (HashFreeFunc) dvmFreeClassInnards);

    gDvm.pBootLoaderAlloc = dvmLinearAllocCreate(NULL);
    if (gDvm.pBootLoaderAlloc == NULL)
        return false;

    if (false) {
        linearAllocTests();
        exit(0);
    }

    /*
     * Class serial number.  We start with a high value to make it distinct
     * in binary dumps (e.g. hprof).
     */
    gDvm.classSerialNumber = INITIAL_CLASS_SERIAL_NUMBER;

    /*
     * Set up the table we'll use for tracking initiating loaders for
     * early classes.
     * If it's NULL, we just fall back to the InitiatingLoaderList in the
     * ClassObject, so it's not fatal to fail this allocation.
     */
    gDvm.initiatingLoaderList = (InitiatingLoaderList*)
        calloc(ZYGOTE_CLASS_CUTOFF, sizeof(InitiatingLoaderList));

    /*
     * Create the initial classes. These are the first objects constructed
     * within the nascent VM.
     */
    if (!createInitialClasses()) {
        return false;
    }

    /*
     * Process the bootstrap class path.  This means opening the specified
     * DEX or Jar files and possibly running them through the optimizer.
     */
    assert(gDvm.bootClassPath == NULL);
    processClassPath(gDvm.bootClassPathStr, true);

    if (gDvm.bootClassPath == NULL)
        return false;

    return true;
}


vm/InitRefs.cpp
bool dvmFindRequiredClassesAndMembers() {
    /*
     * Note: Under normal VM use, this is called by dvmStartup()
     * in Init.c. For dex optimization, this is called as well, but in
     * that case, the call is made from DexPrepare.c.
     */

    return initClassReferences()
        && initFieldOffsets()
        && initConstructorReferences()
        && initDirectMethodReferences()
        && initVirtualMethodOffsets()
        && initFinalizerReference()
        && verifyStringOffsets();
}


vm/oo/Array.cpp

/*
 * Find an array class, by name (e.g. "[I").
 *
 * If the array class doesn't exist, we generate it.
 *
 * If the element class doesn't exist, we return NULL (no exception raised).
 */
ClassObject* dvmFindArrayClass(const char* descriptor, Object* loader)
{
    ClassObject* clazz;

    assert(descriptor[0] == '[');
    //ALOGV("dvmFindArrayClass: '%s' %p", descriptor, loader);

    clazz = dvmLookupClass(descriptor, loader, false);
    if (clazz == NULL) {
        ALOGV("Array class '%s' %p not found; creating", descriptor, loader);
        clazz = createArrayClass(descriptor, loader);
        if (clazz != NULL)
            dvmAddInitiatingLoader(clazz, loader);
    }

    return clazz;
}


vm/oo/Class.cpp
ClassObject* dvmLookupClass(const char* descriptor, Object* loader,
    bool unprepOkay)
{
    ClassMatchCriteria crit;
    void* found;
    u4 hash;

    crit.descriptor = descriptor;
    crit.loader = loader;
    hash = dvmComputeUtf8Hash(descriptor);

    LOGVV("threadid=%d: dvmLookupClass searching for '%s' %p",
        dvmThreadSelf()->threadId, descriptor, loader);

    dvmHashTableLock(gDvm.loadedClasses);
    found = dvmHashTableLookup(gDvm.loadedClasses, hash, &crit,
                hashcmpClassByCrit, false);
    dvmHashTableUnlock(gDvm.loadedClasses);

    /*
     * The class has been added to the hash table but isn't ready for use.
     * We're going to act like we didn't see it, so that the caller will
     * go through the full "find class" path, which includes locking the
     * object and waiting until it's ready.  We could do that lock/wait
     * here, but this is an extremely rare case, and it's simpler to have
     * the wait-for-class code centralized.
     */
    if (found && !unprepOkay && !dvmIsClassLinked((ClassObject*)found)) {
        ALOGV("Ignoring not-yet-ready %s, using slow path",
            ((ClassObject*)found)->descriptor);
        found = NULL;
    }

    return (ClassObject*) found;
}


vm/Hash.cpp
/*
 * Look up an entry.
 *
 * We probe on collisions, wrapping around the table.
 */
void* dvmHashTableLookup(HashTable* pHashTable, u4 itemHash, void* item,
    HashCompareFunc cmpFunc, bool doAdd)
{
    HashEntry* pEntry;
    HashEntry* pEnd;
    void* result = NULL;

    assert(pHashTable->tableSize > 0);
    assert(item != HASH_TOMBSTONE);
    assert(item != NULL);

    /* jump to the first entry and probe for a match */
    pEntry = &pHashTable->pEntries[itemHash & (pHashTable->tableSize-1)];
    pEnd = &pHashTable->pEntries[pHashTable->tableSize];
    while (pEntry->data != NULL) {
        if (pEntry->data != HASH_TOMBSTONE &&
            pEntry->hashValue == itemHash &&
            (*cmpFunc)(pEntry->data, item) == 0)
        {
            /* match */
            //ALOGD("+++ match on entry %d", pEntry - pHashTable->pEntries);
            break;
        }

        pEntry++;
        if (pEntry == pEnd) {     /* wrap around to start */
            if (pHashTable->tableSize == 1)
                break;      /* edge case - single-entry table */
            pEntry = pHashTable->pEntries;
        }

        //ALOGI("+++ look probing %d...", pEntry - pHashTable->pEntries);
    }

    if (pEntry->data == NULL) {
        if (doAdd) {
            pEntry->hashValue = itemHash;
            pEntry->data = item;
            pHashTable->numEntries++;

            /*
             * We've added an entry.  See if this brings us too close to full.
             */
            if ((pHashTable->numEntries+pHashTable->numDeadEntries) * LOAD_DENOM
                > pHashTable->tableSize * LOAD_NUMER)
            {
                if (!resizeHash(pHashTable, pHashTable->tableSize * 2)) {
                    /* don't really have a way to indicate failure */
                    ALOGE("Dalvik hash resize failure");
                    dvmAbort();
                }
                /* note "pEntry" is now invalid */
            } else {
                //ALOGW("okay %d/%d/%d",
                //    pHashTable->numEntries, pHashTable->tableSize,
                //    (pHashTable->tableSize * LOAD_NUMER) / LOAD_DENOM);
            }

            /* full table is bad -- search for nonexistent never halts */
            assert(pHashTable->numEntries < pHashTable->tableSize);
            result = item;
        } else {
            assert(result == NULL);
        }
    } else {
        result = pEntry->data;
    }

    return result;
}

vm/Intern.cpp

/*
 * Prep string interning.
 */
bool dvmStringInternStartup()
{
    dvmInitMutex(&gDvm.internLock);
    gDvm.internedStrings = dvmHashTableCreate(256, NULL);
    if (gDvm.internedStrings == NULL)
        return false;
    gDvm.literalStrings = dvmHashTableCreate(256, NULL);
    if (gDvm.literalStrings == NULL)
        return false;
    return true;
}

vm/Native.cpp
/*
 * Initialize the native code loader.
 */
bool dvmNativeStartup()
{
    gDvm.nativeLibs = dvmHashTableCreate(4, freeSharedLibEntry);
    if (gDvm.nativeLibs == NULL)
        return false;

    return true;
}

vm/native/InternalNative.cpp
/*
 * Set up hash values on the class names.
 */
bool dvmInternalNativeStartup()
{
    DalvikNativeClass* classPtr = gDvmNativeMethodSet;

    while (classPtr->classDescriptor != NULL) {
        classPtr->classDescriptorHash =
            dvmComputeUtf8Hash(classPtr->classDescriptor);
        classPtr++;
    }

    gDvm.userDexFiles = dvmHashTableCreate(2, dvmFreeDexOrJar);
    if (gDvm.userDexFiles == NULL)
        return false;

    return true;
}

vm/Jni.cpp
bool dvmJniStartup() {
    if (!gDvm.jniGlobalRefTable.init(kGlobalRefsTableInitialSize,
                                 kGlobalRefsTableMaxSize,
                                 kIndirectKindGlobal)) {
        return false;
    }
    if (!gDvm.jniWeakGlobalRefTable.init(kWeakGlobalRefsTableInitialSize,
                                 kGlobalRefsTableMaxSize,
                                 kIndirectKindWeakGlobal)) {
        return false;
    }

    dvmInitMutex(&gDvm.jniGlobalRefLock);
    dvmInitMutex(&gDvm.jniWeakGlobalRefLock);
    gDvm.jniGlobalRefLoMark = 0;
    gDvm.jniGlobalRefHiMark = kGrefWaterInterval * 2;

    if (!dvmInitReferenceTable(&gDvm.jniPinRefTable, kPinTableInitialSize, kPinTableMaxSize)) {
        return false;
    }

    dvmInitMutex(&gDvm.jniPinRefLock);

    return true;
}


vm/Profile.cpp
/*
 * Boot-time init.
 */
bool dvmProfilingStartup()
{
    /*
     * Initialize "dmtrace" method profiling.
     */
    memset(&gDvm.methodTrace, 0, sizeof(gDvm.methodTrace));
    dvmInitMutex(&gDvm.methodTrace.startStopLock);
    pthread_cond_init(&gDvm.methodTrace.threadExitCond, NULL);

    assert(!dvmCheckException(dvmThreadSelf()));

    /*
     * Allocate storage for instruction counters.
     */
    gDvm.executedInstrCounts = (int*) calloc(kNumPackedOpcodes, sizeof(int));
    if (gDvm.executedInstrCounts == NULL)
        return false;

#ifdef UPDATE_MAGIC_PAGE
    /*
     * If we're running on the emulator, there's a magic page into which
     * we can put interpreted method information.  This allows interpreted
     * methods to show up in the emulator's code traces.
     *
     * We could key this off of the "ro.kernel.qemu" property, but there's
     * no real harm in doing this on a real device.
     */
    int fd = open("/dev/qemu_trace", O_RDWR);
    if (fd < 0) {
        ALOGV("Unable to open /dev/qemu_trace,err: %s", strerror(errno));
    } else {
        gDvm.emulatorTracePage = mmap(0, SYSTEM_PAGE_SIZE, PROT_READ|PROT_WRITE,
                                      MAP_SHARED, fd, 0);
        close(fd);
        if (gDvm.emulatorTracePage == MAP_FAILED) {
            ALOGE("Unable to mmap /dev/qemu_trace");
            gDvm.emulatorTracePage = NULL;
        } else {
            *(u4*) gDvm.emulatorTracePage = 0;
        }
    }
#else
    assert(gDvm.emulatorTracePage == NULL);
#endif

    return true;
}



vm/analysis/Optimize.cpp
/*
 * Create a table of inline substitutions.  Sets gDvm.inlineSubs.
 *
 * TODO: this is currently just a linear array.  We will want to put this
 * into a hash table as the list size increases.
 */
bool dvmCreateInlineSubsTable()
{
    const InlineOperation* ops = dvmGetInlineOpsTable();
    const int count = dvmGetInlineOpsTableLength();
    InlineSub* table;
    int i, tableIndex;

    assert(gDvm.inlineSubs == NULL);

    /*
     * One slot per entry, plus an end-of-list marker.
     */
    table = (InlineSub*) calloc(count + 1, sizeof(InlineSub));

    tableIndex = 0;
    for (i = 0; i < count; i++) {
        Method* method = dvmFindInlinableMethod(ops[i].classDescriptor,
            ops[i].methodName, ops[i].methodSignature);
        if (method == NULL) {
            /*
             * Not expected.  We only use this for key methods in core
             * classes, so we should always be able to find them.
             */
            ALOGE("Unable to find method for inlining: %s.%s:%s",
                ops[i].classDescriptor, ops[i].methodName,
                ops[i].methodSignature);
            return false;
        }

        table[tableIndex].method = method;
        table[tableIndex].inlineIdx = i;
        tableIndex++;
    }

    /* mark end of table */
    table[tableIndex].method = NULL;

    gDvm.inlineSubs = table;
    return true;
}


vm/reflect/Reflect.cpp
/*
 * For some of the reflection stuff we need to un-box primitives, e.g.
 * convert a java/lang/Integer to int or even a float.  We assume that
 * the first instance field holds the value.
 *
 * To verify this, we either need to ensure that the class has only one
 * instance field, or we need to look up the field by name and verify
 * that it comes first.  The former is simpler, and should work.
 */
bool dvmValidateBoxClasses()
{
    static const char* classes[] = {
        "Ljava/lang/Boolean;",
        "Ljava/lang/Character;",
        "Ljava/lang/Float;",
        "Ljava/lang/Double;",
        "Ljava/lang/Byte;",
        "Ljava/lang/Short;",
        "Ljava/lang/Integer;",
        "Ljava/lang/Long;",
        NULL
    };
    const char** ccp;

    for (ccp = classes; *ccp != NULL; ccp++) {
        ClassObject* clazz;

        clazz = dvmFindClassNoInit(*ccp, NULL);
        if (clazz == NULL) {
            ALOGE("Couldn't find '%s'", *ccp);
            return false;
        }

        if (clazz->ifieldCount != 1) {
            ALOGE("Found %d instance fields in '%s'",
                clazz->ifieldCount, *ccp);
            return false;
        }
    }

    return true;
}

vm/Thread.cpp
/*
 * Finish preparing the parts of the Thread struct required to support
 * JNI registration.
 */
bool dvmPrepMainForJni(JNIEnv* pEnv)
{
    Thread* self;

    /* main thread is always first in list at this point */
    self = gDvm.threadList;
    assert(self->threadId == kMainThreadId);

    /* create a "fake" JNI frame at the top of the main thread interp stack */
    if (!createFakeEntryFrame(self))
        return false;

    /* fill these in, since they weren't ready at dvmCreateJNIEnv time */
    dvmSetJniEnvThreadId(pEnv, self);
    dvmSetThreadJNIEnv(self, (JNIEnv*) pEnv);

    return true;
}

vm/Init.cpp
/*
 * Register java.* natives from our class libraries.  We need to do
 * this after we're ready for JNI registration calls, but before we
 * do any class initialization.
 *
 * If we get this wrong, we will blow up in the ThreadGroup class init if
 * interpreted code makes any reference to System.  It will likely do this
 * since it wants to do some java.io.File setup (e.g. for static in/out/err).
 *
 * We need to have gDvm.initializing raised here so that JNI FindClass
 * won't try to use the system/application class loader.
 */
static bool registerSystemNatives(JNIEnv* pEnv)
{
    // Main thread is always first in list.
    Thread* self = gDvm.threadList;

    // Must set this before allowing JNI-based method registration.
    self->status = THREAD_NATIVE;

    // Most JNI libraries can just use System.loadLibrary, but you can't
    // if you're the library that implements System.loadLibrary!
    loadJniLibrary("javacore");
    loadJniLibrary("nativehelper");

    // Back to run mode.
    self->status = THREAD_RUNNING;

    return true;
}


vm/Native.cpp
/*
 * Load native code from the specified absolute pathname.  Per the spec,
 * if we've already loaded a library with the specified pathname, we
 * return without doing anything.
 *
 * TODO? for better results we should absolutify the pathname.  For fully
 * correct results we should stat to get the inode and compare that.  The
 * existing implementation is fine so long as everybody is using
 * System.loadLibrary.
 *
 * The library will be associated with the specified class loader.  The JNI
 * spec says we can't load the same library into more than one class loader.
 *
 * Returns "true" on success. On failure, sets *detail to a
 * human-readable description of the error or NULL if no detail is
 * available; ownership of the string is transferred to the caller.
 */
bool dvmLoadNativeCode(const char* pathName, Object* classLoader,
        char** detail)
{
    SharedLib* pEntry;
    void* handle;
    bool verbose;

    /* reduce noise by not chattering about system libraries */
    verbose = !!strncmp(pathName, "/system", sizeof("/system")-1);
    verbose = verbose && !!strncmp(pathName, "/vendor", sizeof("/vendor")-1);

    if (verbose)
        ALOGD("Trying to load lib %s %p", pathName, classLoader);

    *detail = NULL;

    /*
     * See if we've already loaded it.  If we have, and the class loader
     * matches, return successfully without doing anything.
     */
    pEntry = findSharedLibEntry(pathName);
    if (pEntry != NULL) {
        if (pEntry->classLoader != classLoader) {
            ALOGW("Shared lib '%s' already opened by CL %p; can't open in %p",
                pathName, pEntry->classLoader, classLoader);
            return false;
        }
        if (verbose) {
            ALOGD("Shared lib '%s' already loaded in same CL %p",
                pathName, classLoader);
        }
        if (!checkOnLoadResult(pEntry))
            return false;
        return true;
    }

    /*
     * Open the shared library.  Because we're using a full path, the system
     * doesn't have to search through LD_LIBRARY_PATH.  (It may do so to
     * resolve this library's dependencies though.)
     *
     * Failures here are expected when java.library.path has several entries
     * and we have to hunt for the lib.
     *
     * The current version of the dynamic linker prints detailed information
     * about dlopen() failures.  Some things to check if the message is
     * cryptic:
     *   - make sure the library exists on the device
     *   - verify that the right path is being opened (the debug log message
     *     above can help with that)
     *   - check to see if the library is valid (e.g. not zero bytes long)
     *   - check config/prelink-linux-arm.map to ensure that the library
     *     is listed and is not being overrun by the previous entry (if
     *     loading suddenly stops working on a prelinked library, this is
     *     a good one to check)
     *   - write a trivial app that calls sleep() then dlopen(), attach
     *     to it with "strace -p <pid>" while it sleeps, and watch for
     *     attempts to open nonexistent dependent shared libs
     *
     * This can execute slowly for a large library on a busy system, so we
     * want to switch from RUNNING to VMWAIT while it executes.  This allows
     * the GC to ignore us.
     */
    Thread* self = dvmThreadSelf();
    ThreadStatus oldStatus = dvmChangeStatus(self, THREAD_VMWAIT);
    handle = dlopen(pathName, RTLD_LAZY);
    dvmChangeStatus(self, oldStatus);

    if (handle == NULL) {
        *detail = strdup(dlerror());
        return false;
    }

    /* create a new entry */
    SharedLib* pNewEntry;
    pNewEntry = (SharedLib*) calloc(1, sizeof(SharedLib));
    pNewEntry->pathName = strdup(pathName);
    pNewEntry->handle = handle;
    pNewEntry->classLoader = classLoader;
    dvmInitMutex(&pNewEntry->onLoadLock);
    pthread_cond_init(&pNewEntry->onLoadCond, NULL);
    pNewEntry->onLoadThreadId = self->threadId;

    /* try to add it to the list */
    SharedLib* pActualEntry = addSharedLibEntry(pNewEntry);

    if (pNewEntry != pActualEntry) {
        ALOGI("WOW: we lost a race to add a shared lib (%s CL=%p)",
            pathName, classLoader);
        freeSharedLibEntry(pNewEntry);
        return checkOnLoadResult(pActualEntry);
    } else {
        if (verbose)
            ALOGD("Added shared lib %s %p", pathName, classLoader);

        bool result = true;
        void* vonLoad;
        int version;

        vonLoad = dlsym(handle, "JNI_OnLoad");
        if (vonLoad == NULL) {
            ALOGD("No JNI_OnLoad found in %s %p, skipping init",
                pathName, classLoader);
        } else {
            /*
             * Call JNI_OnLoad.  We have to override the current class
             * loader, which will always be "null" since the stuff at the
             * top of the stack is around Runtime.loadLibrary().  (See
             * the comments in the JNI FindClass function.)
             */
            OnLoadFunc func = (OnLoadFunc)vonLoad;
            Object* prevOverride = self->classLoaderOverride;

            self->classLoaderOverride = classLoader;
            oldStatus = dvmChangeStatus(self, THREAD_NATIVE);
            if (gDvm.verboseJni) {
                ALOGI("[Calling JNI_OnLoad for \"%s\"]", pathName);
            }
            version = (*func)(gDvmJni.jniVm, NULL);
            dvmChangeStatus(self, oldStatus);
            self->classLoaderOverride = prevOverride;

            if (version != JNI_VERSION_1_2 && version != JNI_VERSION_1_4 &&
                version != JNI_VERSION_1_6)
            {
                ALOGW("JNI_OnLoad returned bad version (%d) in %s %p",
                    version, pathName, classLoader);
                /*
                 * It's unwise to call dlclose() here, but we can mark it
                 * as bad and ensure that future load attempts will fail.
                 *
                 * We don't know how far JNI_OnLoad got, so there could
                 * be some partially-initialized stuff accessible through
                 * newly-registered native method calls.  We could try to
                 * unregister them, but that doesn't seem worthwhile.
                 */
                result = false;
            } else {
                if (gDvm.verboseJni) {
                    ALOGI("[Returned from JNI_OnLoad for \"%s\"]", pathName);
                }
            }
        }

        if (result)
            pNewEntry->onLoadResult = kOnLoadOkay;
        else
            pNewEntry->onLoadResult = kOnLoadFailed;

        pNewEntry->onLoadThreadId = 0;

        /*
         * Broadcast a wakeup to anybody sleeping on the condition variable.
         */
        dvmLockMutex(&pNewEntry->onLoadLock);
        pthread_cond_broadcast(&pNewEntry->onLoadCond);
        dvmUnlockMutex(&pNewEntry->onLoadLock);
        return result;
    }
}

vm/alloc/Alloc.cpp
/*
 * Create some "stock" exceptions.  These can be thrown when the system is
 * too screwed up to allocate and initialize anything, or when we don't
 * need a meaningful stack trace.
 *
 * We can't do this during the initial startup because we need to execute
 * the constructors.
 */
bool dvmCreateStockExceptions()
{
    /*
     * Pre-allocate some throwables.  These need to be explicitly added
     * to the GC's root set (see dvmHeapMarkRootSet()).
     */
    gDvm.outOfMemoryObj = createStockException("Ljava/lang/OutOfMemoryError;",
        "[memory exhausted]");
    dvmReleaseTrackedAlloc(gDvm.outOfMemoryObj, NULL);
    gDvm.internalErrorObj = createStockException("Ljava/lang/InternalError;",
        "[pre-allocated]");
    dvmReleaseTrackedAlloc(gDvm.internalErrorObj, NULL);
    gDvm.noClassDefFoundErrorObj =
        createStockException("Ljava/lang/NoClassDefFoundError;",
            "[generic]");
    dvmReleaseTrackedAlloc(gDvm.noClassDefFoundErrorObj, NULL);

    if (gDvm.outOfMemoryObj == NULL || gDvm.internalErrorObj == NULL ||
        gDvm.noClassDefFoundErrorObj == NULL)
    {
        ALOGW("Unable to create stock exceptions");
        return false;
    }

    return true;
}


vm/Thread.cpp
/*
 * Finish preparing the main thread, allocating some objects to represent
 * it.  As part of doing so, we finish initializing Thread and ThreadGroup.
 * This will execute some interpreted code (e.g. class initializers).
 */
bool dvmPrepMainThread()
{
    Thread* thread;
    Object* groupObj;
    Object* threadObj;
    Object* vmThreadObj;
    StringObject* threadNameStr;
    Method* init;
    JValue unused;

    ALOGV("+++ finishing prep on main VM thread");

    /* main thread is always first in list at this point */
    thread = gDvm.threadList;
    assert(thread->threadId == kMainThreadId);

    /*
     * Make sure the classes are initialized.  We have to do this before
     * we create an instance of them.
     */
    if (!dvmInitClass(gDvm.classJavaLangClass)) {
        ALOGE("'Class' class failed to initialize");
        return false;
    }
    if (!dvmInitClass(gDvm.classJavaLangThreadGroup) ||
        !dvmInitClass(gDvm.classJavaLangThread) ||
        !dvmInitClass(gDvm.classJavaLangVMThread))
    {
        ALOGE("thread classes failed to initialize");
        return false;
    }

    groupObj = dvmGetMainThreadGroup();
    if (groupObj == NULL)
        return false;

    /*
     * Allocate and construct a Thread with the internal-creation
     * constructor.
     */
    threadObj = dvmAllocObject(gDvm.classJavaLangThread, ALLOC_DEFAULT);
    if (threadObj == NULL) {
        ALOGE("unable to allocate main thread object");
        return false;
    }
    dvmReleaseTrackedAlloc(threadObj, NULL);

    threadNameStr = dvmCreateStringFromCstr("main");
    if (threadNameStr == NULL)
        return false;
    dvmReleaseTrackedAlloc((Object*)threadNameStr, NULL);

    init = dvmFindDirectMethodByDescriptor(gDvm.classJavaLangThread, "<init>",
            "(Ljava/lang/ThreadGroup;Ljava/lang/String;IZ)V");
    assert(init != NULL);
    dvmCallMethod(thread, init, threadObj, &unused, groupObj, threadNameStr,
        THREAD_NORM_PRIORITY, false);
    if (dvmCheckException(thread)) {
        ALOGE("exception thrown while constructing main thread object");
        return false;
    }

    /*
     * Allocate and construct a VMThread.
     */
    vmThreadObj = dvmAllocObject(gDvm.classJavaLangVMThread, ALLOC_DEFAULT);
    if (vmThreadObj == NULL) {
        ALOGE("unable to allocate main vmthread object");
        return false;
    }
    dvmReleaseTrackedAlloc(vmThreadObj, NULL);

    init = dvmFindDirectMethodByDescriptor(gDvm.classJavaLangVMThread, "<init>",
            "(Ljava/lang/Thread;)V");
    dvmCallMethod(thread, init, vmThreadObj, &unused, threadObj);
    if (dvmCheckException(thread)) {
        ALOGE("exception thrown while constructing main vmthread object");
        return false;
    }

    /* set the VMThread.vmData field to our Thread struct */
    assert(gDvm.offJavaLangVMThread_vmData != 0);
    dvmSetFieldInt(vmThreadObj, gDvm.offJavaLangVMThread_vmData, (u4)thread);

    /*
     * Stuff the VMThread back into the Thread.  From this point on, other
     * Threads will see that this Thread is running (at least, they would,
     * if there were any).
     */
    dvmSetFieldObject(threadObj, gDvm.offJavaLangThread_vmThread,
        vmThreadObj);

    thread->threadObj = threadObj;

    /*
     * Set the "context class loader" field in the system class loader.
     *
     * Retrieving the system class loader will cause invocation of
     * ClassLoader.getSystemClassLoader(), which could conceivably call
     * Thread.currentThread(), so we want the Thread to be fully configured
     * before we do this.
     */
    Object* systemLoader = dvmGetSystemClassLoader();
    if (systemLoader == NULL) {
        ALOGW("WARNING: system class loader is NULL (setting main ctxt)");
        /* keep going? */
    } else {
        dvmSetFieldObject(threadObj, gDvm.offJavaLangThread_contextClassLoader,
            systemLoader);
        dvmReleaseTrackedAlloc(systemLoader, NULL);
    }

    /* include self in non-daemon threads (mainly for AttachCurrentThread) */
    gDvm.nonDaemonThreadCount++;

    return true;
}

vm/Debugger.cpp
/*
 * System init.  We don't allocate the registry until first use.
 * Make sure we do this before initializing JDWP.
 */
bool dvmDebuggerStartup()
{
    if (!dvmBreakpointStartup())
        return false;

    gDvm.dbgRegistry = dvmHashTableCreate(1000, NULL);
    return (gDvm.dbgRegistry != NULL);
}


vm/alloc/Alloc.cpp
bool dvmGcStartupClasses()
{
    ClassObject *klass = dvmFindSystemClass("Ljava/lang/Daemons;");
    if (klass == NULL) {
        return false;
    }
    Method *method = dvmFindDirectMethodByDescriptor(klass, "start", "()V");
    if (method == NULL) {
        return false;
    }
    Thread *self = dvmThreadSelf();
    assert(self != NULL);
    JValue unusedResult;
    dvmCallMethod(self, method, NULL, &unusedResult);
    return true;
}

vm/Init.cpp
/*
 * Do zygote-mode-only initialization.
 */
static bool initZygote()
{
    /* zygote goes into its own process group */
    setpgid(0,0);

    return true;
}


vm/Init.cpp
/*
 * Do non-zygote-mode initialization.  This is done during VM init for
 * standard startup, or after a "zygote fork" when creating a new process.
 */
bool dvmInitAfterZygote()
{
    u8 startHeap, startQuit, startJdwp;
    u8 endHeap, endQuit, endJdwp;

    startHeap = dvmGetRelativeTimeUsec();

    /*
     * Post-zygote heap initialization, including starting
     * the HeapWorker thread.
     */
    if (!dvmGcStartupAfterZygote())
        return false;

    endHeap = dvmGetRelativeTimeUsec();
    startQuit = dvmGetRelativeTimeUsec();

    /* start signal catcher thread that dumps stacks on SIGQUIT */
    if (!gDvm.reduceSignals && !gDvm.noQuitHandler) {
        if (!dvmSignalCatcherStartup())
            return false;
    }

    /* start stdout/stderr copier, if requested */
    if (gDvm.logStdio) {
        if (!dvmStdioConverterStartup())
            return false;
    }

    endQuit = dvmGetRelativeTimeUsec();
    startJdwp = dvmGetRelativeTimeUsec();

    /*
     * Start JDWP thread.  If the command-line debugger flags specified
     * "suspend=y", this will pause the VM.  We probably want this to
     * come last.
     */
    if (!initJdwp()) {
        ALOGD("JDWP init failed; continuing anyway");
    }

    endJdwp = dvmGetRelativeTimeUsec();

    ALOGV("thread-start heap=%d quit=%d jdwp=%d total=%d usec",
        (int)(endHeap-startHeap), (int)(endQuit-startQuit),
        (int)(endJdwp-startJdwp), (int)(endJdwp-startHeap));

#ifdef WITH_JIT
    if (gDvm.executionMode == kExecutionModeJit) {
        if (!dvmCompilerStartup())
            return false;
    }
#endif

    return true;
}


看一下 com.android.internal.os.ZygoteInit.java的main

 

Java代码  
public static void main(String argv[]) {
        try {
            // Start profiling the zygote initialization.
            SamplingProfilerIntegration.start();

            registerZygoteSocket();
            EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_START,
                SystemClock.uptimeMillis());
            preload();
            EventLog.writeEvent(LOG_BOOT_PROGRESS_PRELOAD_END,
                SystemClock.uptimeMillis());

            // Finish profiling the zygote initialization.
            SamplingProfilerIntegration.writeZygoteSnapshot();

            // Do an initial gc to clean up after startup
            gc();

            // If requested, start system server directly from Zygote
            if (argv.length != 2) {
                throw new RuntimeException(argv[0] + USAGE_STRING);
            }

            if (argv[1].equals("start-system-server")) {
                startSystemServer();
            } else if (!argv[1].equals("")) {
                throw new RuntimeException(argv[0] + USAGE_STRING);
            }

            Log.i(TAG, "Accepting command socket connections");

            if (ZYGOTE_FORK_MODE) {
                runForkMode();
            } else {
                runSelectLoopMode();
            }

            closeServerSocket();
        } catch (MethodAndArgsCaller caller) {
            caller.run();
        } catch (RuntimeException ex) {
            Log.e(TAG, "Zygote died with exception", ex);
            closeServerSocket();
            throw ex;
        }
    }