• Open Menu Close Menu
  • Apple
  • Shopping Bag
  • Apple
  • Mac
  • iPad
  • iPhone
  • Watch
  • TV
  • Music
  • Support
  • Search apple.com
  • Shopping Bag

Lists

Open Menu Close Menu
  • Terms and Conditions
  • Lists hosted on this site
  • Email the Postmaster
  • Tips for posting to public mailing lists
Re: How many bytes is an instruction?
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: How many bytes is an instruction?


  • Subject: Re: How many bytes is an instruction?
  • From: Rick Mann <email@hidden>
  • Date: Wed, 24 Jul 2013 14:03:24 -0700

On Jul 24, 2013, at 13:54 , Jerry Krinock <email@hidden> wrote:

>
> On 2013 Jul 24, at 12:30, Rick Mann <email@hidden> wrote:
>
>> I've got a crash log without good symbolication. It shows the crash as myMethod:+657.
>
> The call (line) *above* myMethod:+657 should tell you the procedure which was called by myMethod where the crash occurred.  Unless you write really long methods, the answer should jump out at you.
>
>> Can I look at disassembly of the file in Xcode and gauge approximately where that crash occurred by counting instructions? Is there a rule of thumb I can use for instruction width?
>
> You shouldn't need to.
>
> If this doesn't make sense, post more of that crash report.

The crash is actually down deeper than that. I'm fairly sure I know what the cause was, and later symbolication showed I was correct, but in general, I wanted to see how to find the offset. Seems like the assembler should be able to output relative address offsets in some form (perhaps with an extra option Xcode doesn't pass because it's trying to make input that the assembler can accept.

In this case, an exception was thrown when inserting nil into a NSCFPlaceholderDictionary. I had a line of code creating a dictionary literal. But it's possible that the dictionary could've been created deep inside Cocoa, in which case it wouldn't have been so obvious. I wanted to try to pinpoint the line of my code that made the offending call. Knowing relative offsets into the assembly would make that a little easier.

--
Rick




 _______________________________________________
Do not post admin requests to the list. They will be ignored.
Xcode-users mailing list      (email@hidden)
Help/Unsubscribe/Update your Subscription:

This email sent to email@hidden


  • Follow-Ups:
    • Re: How many bytes is an instruction?
      • From: Wim Lewis <email@hidden>
References: 
 >How many bytes is an instruction? (From: Rick Mann <email@hidden>)
 >Re: How many bytes is an instruction? (From: Jerry Krinock <email@hidden>)

  • Prev by Date: Re: How many bytes is an instruction?
  • Next by Date: Re: "Commit NNN Files" Button : Why is NNN much > changed files
  • Previous by thread: Re: How many bytes is an instruction?
  • Next by thread: Re: How many bytes is an instruction?
  • Index(es):
    • Date
    • Thread