framework学习包括问题分析的脚手架

打堆栈

打java堆栈

Exception e = new Exception("xxx");
e.printStackTrace();
或者
android.util.Log.d("xxx", e);

打native堆栈

对于c++
mk或者bp文件中引入libutils

#include <utils/CallStack.h>
android::CallStack cs("xxx");

对于c
mk或者bp文件中引入libutils，再在项目里再加入一个c++的头文件，比如callstack.h，里面是：
void dumping_callstack(void);

#include <utils/CallStack.h> 
extern "C" void dumping_callstack(void); 
void dumping_callstack(void) { 
    android::CallStack cs("xxx");

放开系统日志

一般对某个模块不了解，可以全量开启这块的日志，再结合perfetto/systrace进行分析。

一类是protolog
android R才启用

 ProtoLog.v(WM_DEBUG_CONFIGURATION, "Starting activity when config "
                        + "will change = %b", globalConfigWillChange);

NX563J:/ # wm logging -h
Unknown command
Window manager logging options:
    //启动抓取proto logging
  start: Start proto logging 
  //停止抓取proto logging
  stop: Stop proto logging 
  //允许proto logging的输出针对对应group（
  enable [group...]: Enable proto logging for given groups 
  //禁止proto logging的输出针对对应group
  disable [group...]: Disable proto logging for given groups
  //允许locat的输出针对对应group
  enable-text [group...]: Enable logcat logging for given groups
  //禁止locat的输出针对对应group
  disable-text [group...]: Disable logcat logging for given groups
Not handled, please use `adb shell dumpsys activity service SystemUIService WMShell` if you are looking for ProtoLog in WMShell

enable对应是proto logging这个就是像wms课程时候winscope抓取会把日志写入到data/misc/wmtrace/路径下wm_log.winscope
enable-text对应就是logcat可以直接看到的，这个也就是我们经常用的

一类是硬编码的日志开关

public class WindowManagerDebugConfig {
    // All output logs in the window manager package use the {@link #TAG_WM} string for tagging
    // their log output. This makes it easy to identify the origin of the log message when sifting
    // through a large amount of log output from multiple sources. However, it also makes trying
    // to figure-out the origin of a log message while debugging the window manager a little
    // painful. By setting this constant to true, log messages from the window manager package
    // will be tagged with their class names instead fot the generic tag.
    static final boolean TAG_WITH_CLASS_NAME = false;

    // Default log tag for the window manager package.
    static final String TAG_WM = "WindowManager";

    static final boolean DEBUG = false;
    static final boolean DEBUG_LAYOUT = false;
    static final boolean DEBUG_LAYERS = false;
    static final boolean DEBUG_INPUT = false;
    static final boolean DEBUG_INPUT_METHOD = false;
    static final boolean DEBUG_VISIBILITY = false;
    static final boolean DEBUG_CONFIGURATION = false;
    static final boolean DEBUG_STARTING_WINDOW_VERBOSE = false;
    static final boolean DEBUG_WALLPAPER = false;
    static final boolean DEBUG_DRAG = true;
    static final boolean DEBUG_SCREENSHOT = false;
    static final boolean DEBUG_LAYOUT_REPEATS = false;
    static final boolean DEBUG_WINDOW_TRACE = false;
    static final boolean DEBUG_TASK_MOVEMENT = false;
    static final boolean DEBUG_TASK_POSITIONING = false;
    static final boolean DEBUG_ROOT_TASK = false;
    static final boolean DEBUG_DISPLAY = false;
    static final boolean DEBUG_POWER = false;
    static final boolean SHOW_VERBOSE_TRANSACTIONS = false;
    static final boolean SHOW_LIGHT_TRANSACTIONS = false;
    static final boolean SHOW_STACK_CRAWLS = false;
    static final boolean DEBUG_WINDOW_CROP = false;
    static final boolean DEBUG_UNKNOWN_APP_VISIBILITY = false;
}

    private final Predicate<WindowState> mComputeImeTargetPredicate = w -> {
        if (DEBUG_INPUT_METHOD && mUpdateImeTarget) Slog.i(TAG_WM, "Checking window @" + w
                + " fl=0x" + Integer.toHexString(w.mAttrs.flags));
        return w.canBeImeTarget();
    };

看日志

adb logcat只能查看包含main、system 和crash 缓冲区的log。
要查看全部缓冲区日志adb logcat -b all

radio：查看包含无线装置/电话相关消息的缓冲区。

events：查看已经过解译的二进制系统事件缓冲区消息。 EventLog.writeEvent

main：查看主日志缓冲区（默认），不包含系统和崩溃日志消息。Log.d

system：查看系统日志缓冲区（默认）。Slog.d

crash：查看崩溃日志缓冲区（默认）。

all：查看所有缓冲区。

default：包含main、system 和crash 缓冲区

Image.png

查看kernel日志
常见场景如selinux相关dmesg

AS动态调试

编译userdebug镜像或者尝其他方式使得进程可调试

image.png

预期这里会出现system_server等进程。

systrace/perfetto

非常强大的工具，可以用于模块学习或者问题分析。
如何查看trace参考https://blog.csdn.net/learnframework/article/details/135020636
自己添加trace
可以添加的trace包括同步trace（方法、代码块）、异步trace、对于某个值的监听（局限了int和boolean类型，如vsync-sf等）,具体加trace方法参考https://blog.csdn.net/learnframework/article/details/133627031

dumpsys及system_server提供的一些adb命令

特定场景的分析工具

window、surfaceFlinger相关问题

winscope参考https://blog.csdn.net/learnframework/article/details/129432374

anr、watchdog、lowmem

这三种场景下会生成/data/anr/traces.txt

dropbox:/data/system/dropbox有一些持久化的系统日志

system_app_anr：系统app无响应

system_app_crash：系统app进程崩溃

system_server_native_crash system进程native出现崩溃

system_server_wtf：system进程发生严重错误

system_server_lowmem：system进程内存不足