No gcc 4.2 compiler option in Xcode 4?_问答_开发者

In my Xcode 4 installation, I only have 2 compiler options:

Apple LLVM compiler 3.0
GCC LLVM 4.2

In many Xcode examples I have seen that GCC 4.2 is shown as a third option, but this simply isn't there. I intentionally did a clean installation of XCode 4. Is there a standard method for adding GCC 4.2 if it's not already there? One of my projects requires that I use GCC (and n开发者_C百科ot GCC LLVM), the other projects I am happy with GCC LLVM, so it's only an issue for that one.

Here is a way to enable compiling with gcc 4.2 in xcode 4.2. This is mostly done via command line so when you see lines starting with: [ 15:30 jon@MacBookPro / ]$, you need to open up Terminal.app and run the command that starts after the $.

No files or directories are removed or deleted in this process, so it is easy to undo if you need to compile with LLVM in the future.

Download - but do not install yet - xcode_4.1_for_lion.dmg or xcode_4.1_for_snow_leopard.dmg
Now, follow these steps to install Xcode 4.1 into /Developer-4.1:
1. Backup the working /Developer directory (where Xcode 4.2 is installed)
2. Run the Xcode 4.1 installer using the default install location (/Developer)
3. Move the new Xcode 4.1 installation to /Developer-4.1:
```
[ 15:30 jon@MacBookPro / ]$ sudo mv -v /Developer /Developer-4.1
```
4. Move the Xcode 4.2 developer directory back to /Developer:
```
[ 15:30 jon@MacBookPro / ]$ sudo mv -v /Developer-4.2 /Developer
```

Edit the Xcode 4.2 GCC 4.2.xcspec file to get gcc 4.2 to show in the list of compiler options ^[1]:

[ 15:30 jon@MacBookPro / ]$ sudo vi "/Developer/Library/Xcode/PrivatePlugIns/Xcode3Core.ideplugin/Contents/SharedSupport/Developer/Library/Xcode/Plug-ins/GCC 4.2 (Plausible Blocks).xcplugin/Contents/Resources/GCC 4.2.xcspec"

Change lines 41 and 42 from this:

ShowInCompilerSelectionPopup = NO;
IsNoLongerSupported = YES;

To This:

ShowInCompilerSelectionPopup = YES; 
IsNoLongerSupported = NO;

Backup the Xcode 4.2 iOS/Simulator Framework usr directories:

[ 15:30 jon@MacBookPro / ]$ sudo mv -v /Developer/Platforms/iPhoneOS.platform/Developer/usr /Developer/Platforms/iPhoneOS.platform/Developer/usr.backup
[ 15:30 jon@MacBookPro / ]$ sudo mv -v /Developer/Platforms/iPhoneSimulator.platform/Developer/usr /Developer/Platforms/iPhoneSimulator.platform/Developer/usr.backup

Copy Xcode 4.1 iOS/Simulator Framework usr directories to Xcode 4.2:

[ 15:30 jon@MacBookPro / ]$ sudo cp -rv /Developer-4.1/Platforms/iPhoneOS.platform/Developer/usr /Developer/Platforms/iPhoneOS.platform/Developer/usr
[ 15:30 jon@MacBookPro / ]$ sudo cp -rv /Developer-4.1/usr /Developer/Platforms/iPhoneSimulator.platform/Developer/usr

Copy the gcc and info iOS SDK library directories from Xcode 4.1 to Xcode 4.2 ^[2]:

[ 15:30 jon@MacBookPro / ]$ sudo cp -rv /Developer-4.1/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.3.sdk/usr/lib/gcc /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.0.sdk/usr/lib/gcc
[ 15:30 jon@MacBookPro / ]$ sudo cp -rv /Developer-4.1/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.3.sdk/usr/lib/info /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.0.sdk/usr/lib/info

Compile using gcc-4.2!

This is a blog post I've written with a little more info about this process. Feel free to leave a comment on the blog if you run into any issues or have any questions.

^[1] If opening from a command line (using something like vi, emacs, nano, etc) make sure to either enclose the path in quotes "/long path/with spaces/in it/file.xcspec" or escape the spaces /some/long\ path/with\ spaces/in\ it/file.xcspec

^[2] This is necessary because the iPhoneOS.platform SDK has its own seperate /usr/lib directories but the iPhoneSimulator.platform SDK does not

Xcode 4.3 has a specific folder /Applications/Xcode.app/Contents/Developer/Toolchains.

Is there a way to add other tool-chains as AVR-gcc and PIC32-gcc?