符号异常断点 - - [NSRangeException raise] [英] Symbolic exception breakpoint on -[NSRangeException raise]

问题描述

在Xcode中添加一个符号断点为您提供了一个 - [NSException raise] 的示例模板。我想在 - [NSRangeException raise] 上执行相同的操作，但 特别 。原因是我想在特定的数组边界异常处断点 ，例如：

  ***因未捕获异常'NSRangeException'而终止应用程序，原因：'***  -  [__ NSArrayI objectAtIndex：]：index 31超越范围[0 .. 30]'
  

是的，我知道我可以添加一个捕获所有异常断点。然而，我不想这样做，因为我不想断开整个使用应用程序生成的许多异常。

我尝试了很多基于在与 NSException 相关的其他帖子上。然而，我还没有发现任何成功的工作。

例如，我尝试过：

尽管没有结果：

因此，基本上，问题是，在Xcode中，如何特别指定断点并只在范围异常？

解决方案

NSRangeException不是类：

grep NSRangeException /System/Library/Frameworks/Foundation.framework/Headers/NSException.h
FOUNDATION_EXPORT NSString * const NSRangeException;

原来，范围异常只是名称为NSRangeException的NSExceptions，即：

 $ 58216恢复
过程58216停止
 *线程＃1：tid = 0x1d7f4b，函数：objc_exception_throw，停止原因=断点2.1 
帧＃0：0x00007fff8e3c2e4a libobjc.A.dylib`objc_exception_throw 
 libobjc.A.dylib`objc_exception_throw：
  - > 0x7fff8e3c2e4a：pushq％rbp 
 0x7fff8e3c2e4b：movq％rsp，％rbp 
 0x7fff8e3c2e4e：pushq％r15 
 0x7fff8e3c2e50：pushq％r14 
（lldb）bt 
 * 1：tid = 0x1d7f4b，函数：objc_exception_throw，stop reason =断点2.1 
 frame＃0：0x00007fff8e3c2e4a libobjc.A.dylib`objc_exception_throw 
 frame＃1：0x00007fff841ca1df CoreFoundation`  -  [__ NSArrayI objectAtIndex：] 
帧＃2：0x0000000100000eb9范围 - 异常 -  [Foo throwIt]范围异常.m：14 
帧＃3：0x0000000100000f27范围异常`范围-exception.m：22 
 frame＃4：0x00007fff8468d5fd libdyld.dylib`start 
 frame＃5：0x00007fff8468d5fd libdyld.dylib`start 
（lldb）expr（NSString *）[（（NSException *）$ arg1）name] 
（NSString *）$ 0 = 0x00007fff74177990 @NSRangeException
  

所以你可以在objc_exception_throw上设置一个断点，并编写一个断点条件，将名称与NSRangeException进行比较。例如：

  [（NSString *）[（（NSException *）$ arg1）name] isEqual：（NSString *）NSRangeException ] 
  

应该可以做到。

Adding a symbolic breakpoint in Xcode gives you an example template of -[NSException raise]. I want to do the same thing but specifically on -[NSRangeException raise]. The reason being that I want to breakpoint only on specific array bounds exceptions, for example:

*** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayI objectAtIndex:]: index 31 beyond bounds [0 .. 30]'

Yes, I know that I can add a catch all exception breakpoint. However, I do not want to do that as I do not want to breakpoint on the many exceptions generated throughout using the app.

I've tried quite a few things based on other posts related to NSException. However, I have not found anything that works successfully as yet.

For example I tried:

This journal entry was also of interest albeit inconclusive:

Dealing with NSArray "out of bounds"

So, basically, the question is, in Xcode, how to breakpoint specifically and only on a range exception?

解决方案

NSRangeException isn't a class:

grep NSRangeException /System/Library/Frameworks/Foundation.framework/Headers/NSException.h FOUNDATION_EXPORT NSString * const NSRangeException;

Turns out, range exceptions are just NSExceptions whose name is NSRangeException, i.e.:

(lldb) b s -n objc_exception_throw
Breakpoint 2: where = libobjc.A.dylib`objc_exception_throw, address = 0x00007fff8e3c2e4a
(lldb) c
Process 58216 resuming
Process 58216 stopped
* thread #1: tid = 0x1d7f4b, function: objc_exception_throw , stop reason = breakpoint 2.1
    frame #0: 0x00007fff8e3c2e4a libobjc.A.dylib`objc_exception_throw
libobjc.A.dylib`objc_exception_throw:
-> 0x7fff8e3c2e4a:  pushq  %rbp
   0x7fff8e3c2e4b:  movq   %rsp, %rbp
   0x7fff8e3c2e4e:  pushq  %r15
   0x7fff8e3c2e50:  pushq  %r14
(lldb) bt 
* thread #1: tid = 0x1d7f4b, function: objc_exception_throw , stop reason = breakpoint 2.1
    frame #0: 0x00007fff8e3c2e4a libobjc.A.dylib`objc_exception_throw
    frame #1: 0x00007fff841ca1df CoreFoundation`-[__NSArrayI objectAtIndex:]
    frame #2: 0x0000000100000eb9 range-exception`-[Foo throwIt] at range-exception.m:14
    frame #3: 0x0000000100000f27 range-exception`main at range-exception.m:22
    frame #4: 0x00007fff8468d5fd libdyld.dylib`start
    frame #5: 0x00007fff8468d5fd libdyld.dylib`start
(lldb) expr (NSString *) [((NSException *) $arg1) name]
(NSString *) $0 = 0x00007fff74177990 @"NSRangeException"

So you could set a breakpoint on objc_exception_throw, and write a breakpoint condition comparing the name to NSRangeException. Something like:

[(NSString *) [((NSException *) $arg1) name] isEqual: (NSString *) NSRangeException]

should do the trick.

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