相信大部分人都有使用過lldb命令進行調試程序，如po一個對象，打印出該對象的屬性，lldb是一個有著REPL的特性的開源調試器，還可以支持C++,Python插件。本文要講的就是利用Facebook開源的外部插件(Chisel)增強lldb的調試。
1.安裝Chisel
奉上Chisel源碼地址
首先Chisel的安裝要使用homebrew，homebrew安裝可以看這里，本文不多敘述
打開終端，輸入一下命令
brew update
brew install chisel
安裝完成后還要安裝日志提示在``/.lldbinit`添加一行，如果沒有該文件也可以新建一個，然后重啟Xcode,令Chisel生效
2.使用Chisel
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pvc命令，該命令可以遞歸打印viewcontroller的層級，利用該命令我們可以清楚的看到viewcontroller的層級結構,還可以查看view的加載情況。
pvc
<IWTabBarController 0x7fa5f3db2580>, state: appeared, view: <UILayoutContainerView 0x7fa5f3d32c80> | <UINavigationController 0x7fa5f4869000>, state: appeared, view: <UILayoutContainerView 0x7fa5f3df9ec0> | | <IWHomeViewController 0x7fa5f3db4eb0>, state: appeared, view: <UITableView 0x7fa5f4052e00> | <UINavigationController 0x7fa5f409d000>, state: disappeared, view: <UILayoutContainerView 0x7fa5f3c70930> not in the window | | <IWMessageViewController 0x7fa5f3e72520>, state: disappeared, view: (view not loaded) | <UINavigationController 0x7fa5f4868a00>, state: disappeared, view: <UILayoutContainerView 0x7fa5f3ececb0> not in the window | | <IWDiscoverViewController 0x7fa5f3e94990>, state: disappeared, view: (view not loaded) | <UINavigationController 0x7fa5f488e000>, state: disappeared, view: <UILayoutContainerView 0x7fa5f3f144b0> not in the window | | <IWMeViewController 0x7fa5f3ed4650>, state: disappeared, view: (view not loaded)
3.pviews 命令遞歸查看view的層級結構,打印出每個view的frame，是否接受點擊等，方便調試。
pviews self.view
<UIView: 0x7fbbdb4c8ac0; frame = (0 0; 414 736); autoresize = W+H; layer = <CALayer: 0x7fbbdb4c7b30>> | <_UILayoutGuide: 0x7fbbdb4c8e90; frame = (0 0; 0 0); hidden = YES; layer = <CALayer: 0x7fbbdb4c7730>> | <_UILayoutGuide: 0x7fbbdb4c99e0; frame = (0 0; 0 0); hidden = YES; layer = <CALayer: 0x7fbbdb4c7a20>> | <UIView: 0x7fbbdb4cbf90; frame = (100 100; 150 150); layer = <CALayer: 0x7fbbdb4cb600>> | | <UILabel: 0x7fbbdb4c80a0; frame = (0 0; 100 100); text = 'chisel'; userInteractionEnabled = NO; layer = <_UILabelLayer: 0x7fbbdb4c8490>>
2.fv 和 fvc ，這兩個命令都是用來查看當前內存中存在的實例對象，其中fv是對view進行搜索，而fvc是對viewcontroller進行搜索，二者都支持正則搜索
(lldb) fv cus 0x7fd5aa63deb0 IWCustomerCell 0x7fd5aa537240 IWCustomerCell 0x7fd5aa7959e0 IWCustomerCell 0x7fd5aa793460 IWCustomerCell 0x7fd5aa7915c0 IWCustomerCell 0x7fd5aa78daf0 IWCustomerCell (lldb) fvc home 0x7fd5aa4aa340 IWHomeViewController
5.show和hide命令，這兩個命令可以顯示或者隱藏某個viewOrLayer
6.caflush這個命令會重新繪制界面，當你在調試界面顏色或者坐標之類的時候可以直接在控制臺修改view的屬性，然后caflush就可以看到效果了
(lldb) p self.tview (UIView *) $2 = 0x00007f8651564a60 (lldb) e (void)[$1 setBackgroundColor:[UIColor greenColor]] (lldb) caflush
7,bmessage該命令用于打斷點。在日常調試中,我們可能在[MyViewController viewWillAppear:]中添加斷點調試，但是如果該方法沒有實現，通常做法是子類中實現，然后打斷點。現在使用bmessage也可以試下調試功能(lldb) bmessage -[MyViewController viewWillAppear:],上面命令可以在其父類的viewWillAppear:中打斷點，
8，visualize 一個有意思的命令,它可以讓你使用預覽打開一個 UIImage, CGImageRef, UIView, 或 CALayer。定位到每個view的具體情況
(lldb) visualize imageView
3,Last but the most important
Reference article
Debug of Xcode: Fix Console po frame Printing
Dancing in the Debugger — A Waltz with LLDB
Chisel official description
