MantisBT - CMake
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IDProjectCategoryView StatusDate SubmittedLast Update
0014736CMakeCMakepublic2014-02-05 05:442015-11-02 09:13
Reporterlando 
Assigned ToBrad King 
PrioritylowSeverityminorReproducibilityalways
StatusclosedResolutionfixed 
PlatformAppleOSOSXOS Version10.9.1
Product VersionCMake 2.8.12.1 
Target VersionCMake 3.3Fixed in VersionCMake 3.3 
Summary0014736: Xcode warning due to set ARCHS (CMAKE_OSX_ARCHITECTURES) variable in project
DescriptionI'm using CMake-generated Xcode-projects in Xcode 5.0.2 and get a warning by Xcode that it wants to "Update to recommended settings", specifically to set to "Automatically Select Architectures".

This is due to a set ARCHS-variable in the pbxproj-file of the Xcode project. Alas, even setting the variable to the Xcode default value $(ARCHS_STANDARD) via CMAKE_OSX_ARCHITECTURES does not help. Xcode complains as long as the line is present in the project file.
Steps To Reproduce
Additional Information
TagsNo tags attached.
Relationships
has duplicate 0015360closed  XCode generated project yield "Project 'X' overrides the Architectures setting" warning 
has duplicate 0015376closed  CMake creates Xcode project with invalid project settings 
Attached Filespatch fix_xcode_warning.patch (1,746) 2015-03-27 08:46
https://public.kitware.com/Bug/file/5414/fix_xcode_warning.patch
Issue History
Date ModifiedUsernameFieldChange
2014-02-05 05:44landoNew Issue
2014-02-06 10:37Brad KingNote Added: 0035045
2014-02-07 07:56landoNote Added: 0035048
2014-02-07 08:34Brad KingNote Added: 0035049
2014-07-30 06:31Jan RüeggNote Added: 0036496
2014-10-15 18:19birardaNote Added: 0037035
2015-01-20 09:03Brad KingRelationship addedhas duplicate 0015360
2015-01-20 13:59Laurent DemaillyNote Added: 0037756
2015-01-27 14:01Brad KingRelationship addedhas duplicate 0015376
2015-03-27 08:46Jan RüeggFile Added: fix_xcode_warning.patch
2015-03-27 08:47Jan RüeggNote Added: 0038345
2015-03-27 09:01Brad KingNote Added: 0038346
2015-03-27 12:19Jan RüeggNote Added: 0038350
2015-03-27 13:18Brad KingNote Added: 0038351
2015-03-27 13:18Brad KingAssigned To => Brad King
2015-03-27 13:18Brad KingStatusnew => resolved
2015-03-27 13:18Brad KingResolutionopen => fixed
2015-03-27 13:18Brad KingFixed in Version => CMake 3.3
2015-03-27 13:18Brad KingTarget Version => CMake 3.3
2015-03-27 13:23Brad KingNote Added: 0038352
2015-11-02 09:13Robert MaynardNote Added: 0039750
2015-11-02 09:13Robert MaynardStatusresolved => closed

Notes
(0035045)
Brad King   
2014-02-06 10:37   
By setting CMAKE_OSX_ARCHITECTURES explicitly you are telling CMake what to put in ARCHS. If you don't set it then CMake generates $(ARCHS_STANDARD_32_64_BIT), which was the default as of Xcode 3.2 and still works in 5. However, it also enables ONLY_ACTIVE_ARCH to build only for the host.

When you set CMAKE_OSX_ARCHITECTURES to $(ARCHS_STANDARD) then Xcode is complaining that the settings are per-target rather than project-wide. BTW, CMake does not officially support this because it expects a ;-list of architecture names in CMAKE_OSX_ARCHITECTURES.

In either case, Xcode is complaining that the project settings make it difficult for a human to make sweeping changes to the architecture selection through the IDE. For a CMake-generated project this doesn't matter because it should not be modified by hand through the IDE anyway.
(0035048)
lando   
2014-02-07 07:56   
Quote:
"By setting CMAKE_OSX_ARCHITECTURES explicitly you are telling CMake what to put in ARCHS. If you don't set it then CMake generates $(ARCHS_STANDARD_32_64_BIT), which was the default as of Xcode 3.2 and still works in 5."

Yes, I already looked that up in the source code. Unfortunately, that seems to make it impossible to create a warning-free Xcode project for us. As the warning pops up as any compiler or linker warning, this glitch appears in our automatic build test logs. Admittedly, that's not exactly severe, but... *shrug*
(0035049)
Brad King   
2014-02-07 08:34   
Re 0014736:0035048: Using the Xcode IDE by hand without CMake, how does one create a project that has two targets such that one builds with one architecture and another builds with a different architecture but Xcode does not produce this warning?
(0036496)
Jan Rüegg   
2014-07-30 06:31   
Yes, I agree, this is still the case. To solve the issue, the "ARCHS" line has to be removed completely from the project file. (This is by the way what the IDE does when you press "update to recommended settings").

However, currently there is no way to do this from a CMakeLists.txt file, since it is hardcoded in

http://cmake.org/gitweb?p=cmake.git;a=blob;f=Modules/CompilerId/Xcode-3.pbxproj.in [^]
(0037035)
birarda   
2014-10-15 18:19   
Found this while searching for a solution to the "update to recommended settings" warning.

Would it be possible to have ARCHS removed from the standard project file unless explicitly set via CMAKE_OSX_ARCHITECTURES?
(0037756)
Laurent Demailly   
2015-01-20 13:59   
my project doesn't have architecture and does get this warning
(gory details in http://www.cmake.org/Bug/view.php?id=15360 [^] )
(0038345)
Jan Rüegg   
2015-03-27 08:47   
I just uploaded a patch with a possible fix. This will not set the ARCHS flag to some variable, but just leave it empty, letting XCode fill the variable itself with what is most correct.

On my machine, this works fine and fixes the issue.
(0038346)
Brad King   
2015-03-27 09:01   
Can anyone answer my question in 0014736:0035049? Xcode is basically warning that we're using a feature they provide.
(0038350)
Jan Rüegg   
2015-03-27 12:19   
Re http://www.cmake.org/Bug/view.php?id=14736#c38346 [^]

As far as I understand XCode automatically selects for what architectures to compile depending on the hardware attached to the phone, or the requirements of an upload to the app store. Setting it manually interferes with that by forcing XCode to compile for a certain architecture.

But that's just my guess. Its's the same with a compiler warning: You are allowed to do it (for example, create an unused variable), but the compiler will warn you that its not best practise to do so...
(0038351)
Brad King   
2015-03-27 13:18   
I've drafted a commit to fix this:

 Xcode: Set ARCHS only when CMAKE_OSX_ARCHITECTURES is specified
 http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=b76b52c0 [^]
(0038352)
Brad King   
2015-03-27 13:23   
Re 0014736:0038350: Compilers warn about cases that are generally known to not be useful. My question is about the case when the developer knows what he/she is doing and really wants to build some binaries for one architecture and some for another. There does not seem to be a warning-free way to do this.

Anyway, the commit linked in 0014736:0038351 should fix this warning. The commit message justifies the change for the general use case. The lack of such justification in the discussion here is why I hesitated to make this change for so long.
(0039750)
Robert Maynard   
2015-11-02 09:13   
Closing resolved issues that have not been updated in more than 4 months.