[cmake-developers] [CMake 0015794]: The Xcode generator consumes all arguments beginning with "-O" even when they're not optimization flags.

[Mantis Bug Tracker]

The following issue has been SUBMITTED. 
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https://cmake.org/Bug/view.php?id=15794 
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Reported By:                Davy Durham
Assigned To:                
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Project:                    CMake
Issue ID:                   15794
Category:                   CMake
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
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Date Submitted:             2015-10-15 13:12 EDT
Last Modified:              2015-10-15 13:12 EDT
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Summary:                    The Xcode generator consumes all arguments beginning
with "-O" even when they're not optimization flags.
Description: 
cmake, when generating Xcode projects, attempts to translate optimization (i.e.
arguments starting with -O…) flags into the proper Xcode project file setting.
 In doing so, it removes all arguments beginning with "-O" from the
CMAKE_CXX_FLAGS and CMAKE_C_FLAGS variables and they do not get passed to the
OTHER_CPLUSPLUSFLAGS and OTHER_CFLAGS values in the Xcode project.  However
flags such as "-ObjC" and "-ObjC++" get incorrectly stripped out of the
generated project.

I have attached a patch file that addresses the issue by ignoring arguments that
begin with -O which are longer than 3 characters. (two files, one for cmake-3.1
and the other for git master)

Steps to Reproduce: 
For a CMakeLists.txt file containing:

  cmake_minimum_required(VERSION 3.0.2)
  project(foo)
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ObjC++")
  add_executable(foo foo.cpp)

running: cmake -G Xcode <path>  results in a generated
foo.xcodeproj/project.pbxproj file
This file's OTHER_CPLUSPLUSFLAGS= value ought to contain -ObjC++, but it does
not.


Additional Information: 
One can work around the issue by adding adding quotes around the argument which
Xcode strips off but cmake doesn't check for (it technically should.. another
bug?)

Example:
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} \"-ObjC++\"")

This is a fragile work around and may not work as it currently does in future
versions of cmake and Xcode
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Issue History 
Date Modified    Username       Field                    Change               
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2015-10-15 13:12 Davy Durham    New Issue                                    
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