[] (http://openradar.appspot.com/radar?id=4976964230184960)

• State: Duplicate (closed)
• Product: Developer Tools
• Rank: No Value
• Date: 11-Nov-2016 00:13 AM

Duplicate of 28529594 (closed)

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When using incremental link-time optimisation in Xcode, breakpoints won’t trigger...

The program will execute as if no breakpoints were set.

This only happen when LTO is set to incremental.
Targets without LTO or with the old monolithic LTO are not affected.

This is always reproductible, no matter which language is used.

Attached is an example Xcode project which demonstrates the issue.

It only consist of a main.m file, with a “hello, world”.

Try putting a breakpoint somewhere in the main function.

Now there’re two schemes you need to test:

• LTO - With link-time optimisation.
  Breakpoint won’t trigger.
• NO-LTO - Without link-time optimisation. Breakpoint will be hit as expected.

The breakpoint should be hit with both schemes.

Breakpoint is not hit when using the scheme with incremental LTO.

• macOS Sierra 10.12.2 Beta (16C41B)
• Xcode version 8.1 (8B62)

Note that the issue is also reproductible with Xcode version 8.2 beta (8C23)

The issue always occurs when using incremental LTO.

Owner:			Jean-David Gadina - XS-Labs
Web:			www.xs-labs.com
Blog:			www.noxeos.com
Twitter:		@macmade
GitHub:			github.com/macmade
LinkedIn:		ch.linkedin.com/in/macmade/
StackOverflow:	stackoverflow.com/users/182676/macmade