What is the best way to integrate a custom clang toolchain
into Xcode5?
I tried to replace the standard clang with mine and got many errors about missing header files.
You can't. Apple patches Clang before it ships it with XCode, to accept certain options that the IDE uses when calling Clang.
You can always use a non-XCode project build system and build outside the IDE. Or use a different IDE.
If you still want to try, it sounds like you didn't configure Clang correctly to find all your system's header files. You need to configure Clang to use the ones you want using
--with-c-include-dirs
--with-cxx-include-dirs
or something like this. Inspect LLVM's configure --help output on the real options and what they should be, I can't seem to find any decent documentation currently.
Related
I am working on a project that uses a GCC library (SFML), which is not available for clang, as far as I know. I am using COC with vim for code completions, but for C++ it needs clangd. Is there a way to use GCC as my compiler, but still use the clangd language server?
I have also heard that there may be a way to make clang recognize GCC libraries/headers, but I've never been able to make it work right. If somebody could point me in the right direction there that would be helpfull too. But I'm used to GCC (I've been using it since I started programming C++), so being able to use clangd and GCC would be preferable.
Yes it is. I do it with ccls (which is clang based as well).
Given my installation of clang is not the standard one (I compile it, tune it to use libc++ by default, and I install it somewhere in my personal space) I have to inject paths to header files known by clang but unknown by other clang based tools.
I obtain them with
clang++ -E -xc++ - -Wp,-v < /dev/null
Regarding the other options related to the current project, I make sure to have a compile_commands.json compilation database (generated by CMake, or bear if I have no other choice), and ccls can work from there. I expect clangd to be quite similar in these aspects.
Ops, answered the wrong question.
But for those who use ccls:
create a .ccls file in your project directory and append --gcc-toolchain=/usr to it.
use this tool to generate a compile_commands.json file
see https://github.com/MaskRay/ccls/wiki/FAQ#compiling-with-gcc
I'm trying to use LLVM to implement a compiler for a toy language. Something like the Kaleidoscope Tutorial. I'm using Visual Studio on 64 bit Windows.
I've managed to build LLVM and clang using VS, but now I want to use the LLVM libraries in my own project. It seems like a silly question but how to I do this? What compiler options do I need? What libraries should I link with etc. etc.
As far as I can see this isn't covered anywhere in the LLVM documentation although I could have easily missed it.
I discovered llvm-config which is designed to solve the problems I'm having. It often seems to give incorrect information (for instance llvm-config --includedir is wrong) but it at least gives me a list of libraries to link with.
I suppose I could also use CMake to generate project files, but CMake seems to be difficult to learn from free resources.
I want to force Xcode to use a custom compiler ('clang-llvm' build from the src) so I can use the clang plugin. My Xcode version is 7.3.1.
People say it is possible with custom toolchains. I didn't make a research on them because easier solution worked well for me:
It is also possible to run frontend plugins directly by setting appropriate "build settings" of Xcode. (Several ways to do this, you can set them on the command line for instance: xcodebuild build FOO=bla.) Here are a few build settings that I found useful to inject C flags:
OTHER_CFLAGS, OTHER_CPLUSPLUSFLAGS or to replace the compiler(s) and linker(s):
CC, CPLUSPLUS, LD, LDPLUSPLUS, LIBTOOL
The same approach works to control the "analyze" action: CLANG_ANALYZER_EXEC, CLANG_ANALYZER_OTHER_FLAGS
Disclaimer: some of those build settings are undocumented (afaik). Use at your own risk.
(Taken from [cfe-dev] Compile/refactor iOS Xcode projects)
For me it was enough to define the following User-Defined Settings in Build Settings of Xcode projects:
CC=my-c-compiler
CXX=my-cxx-compiler
LIBTOOL=my-linker-for-static-libraries
If you use CMake, the way to inject your compiler automatically is to use
set_target_properties(your-target PROPERTIES XCODE_ATTRIBUTE_CC "${YOUR_CC}")
set_target_properties(your-target PROPERTIES XCODE_ATTRIBUTE_CXX "${YOUR_CXX}")
Couple of years ago I've written an article that addresses exactly the problem you describe: Creating and using Clang plugin with Xcode
To enable custom clang you need to actually patch internals of Xcode.app itself, it is technically doable but:
it will break when you update Xcode
it will work correctly on your machine
the version of a plugin and your compiler should match, i.e.
they should be compiled using the same tree
So in general it doesn't really scale, so be careful :)
There's a somewhat obscure feature of Xcode where it supports "alternative toolchains". For example, Swift.org provides installable toolchains for Swift built from current sources.
Unfortunately, while Apple's documentation describes how to install and use such alternative toolchains, it doesn't describe how to create them. There are scripts in the Swift source base which build a toolchain and you can look at them to figure out how it's done. They are in https://github.com/apple/swift/tree/master/utils. Start at build-toolchain, which calls build-script and go from there.
Method 1: Change the User Defined settings
Under the project or target Build Settings add the User Defined settings for
CC=/path/to/cc
CXX=/path/to/c++
This is useful if you have a single compiler or linker you want to call, or if you want to call out to a trampoline that decides what to call on the fly.
Method 2: Create a complete custom toolchain via plugin
Using Clang LLVM 1.0.xcplugin as a template (found in the Xcode.app plugins folder), you can modify the plist to point at your own alternative compiler and linker.
This OLLVM on iOS tutorial walks through it.
From project setting go to build setting with target selected. then select All beside the Basic from the top bar. then under build option you can see the compiler option.
Refer below screenshot,
Update :
I think you should refer Using C and C++ in an iOS App with Objective-C++ and this tutorial.
There seem to a variety of questions like this one without any clear solution that is true for Xcode 7 (or even other versions of Xcode).
I have a version of GCC that I'd like Xcode to use when it compiles. It is not the standard GCC but customized for a different platform. I can specify and use this compiler fine in Eclipse, but would rather use Xcode. The Build Options only list LLVM and nothing else. When I try to add via "other" in that section, all I get is this empty popup:
What goes in this box? I would think that it should be no big deal for Xcode to simply use a GCC that I have available at a specific path on my system, but this appears to be quite complex.
Update: Apparently there is a supported mechanism for installing externally-provided tool chains in Xcode that I wasn't aware of. For example, one can download packages from swift.org that install alternative tool chain packages into /Library/Developer/Toolchains or ~/Library/Developer/Toolchains. Once one of those is installed, Xcode has a GUI option to switch the active tool chain.
There was a recent change to the Swift sources to include a script for building one's own custom tool chain from them.
If you view the Quick Help for that build setting (View > Utilities > Show Quick Help Inspector) or configure the build settings view to show setting names instead of titles (Editor > Show Setting Names), you'll see that that setting is GCC_VERSION.
If you look that up in the Build Settings Reference, you find:
GCC_VERSION
Description:
Numeric identifier. Identifies the GCC version to be used to compile
the target’s source files. When the target’s “System C rule” is set to
GCC System Version (instead of a specific version number), this build
setting is not available in Run Script build phases.
Values:
2.95.2
3.1
3.3
4.0
Default value:
GCC system version.
Specified in:
Project Info > Rules > “System C rule.”
Target Info > Rules > “System C rule.”
Affects:
GCC_VERSION_IDENTIFIER.
That's actually a bit out of date. It says it's specified by fiddling with a build rule (not setting) called the "System C rule". You used to change the version there but now there's a direct build setting for it.
Anyway, this probably doesn't help you do what you want to do. I doubt there's any value you could put in there that would do something useful, let alone use a third-party compiler.
However, the explanation does have a hint. It mentions the System C build rule. You could modify the build rules on the Build Rules tab of the target configuration screen. You can find the System C rule and press the button to copy it to your target, which will let you specify a custom script to process C files (including Objective-C and C++).
Implementing such a script is non-trivial. The inputs, expected outputs, and required behavior of the script are not well documented. There are various environment variables available for the use of such a script. Some are the build settings. You'll need to translate the relevant settings into compiler options. For example, translate the CLANG_WARN_BOOL_CONVERSION setting into the corresponding -Wbool-conversion option.
Some of the other environment variables indicate which file you should operate on, such as INPUT_FILE_PATH, INPUT_FILE_NAME, etc.
You need to tell Xcode what file(s) your rule outputs. These can be based on the input environment variables/settings, such as $(OBJECT_FILE_DIR)-$(CURRENT_VARIANT)/$(CURRENT_ARCH)/$(INPUT_FILE_BASE).o.
In general, this is just not something that Xcode makes easy.
Someone wrote a plugin that will allow you to use gcc from Xcode.
http://hamelot.io/programming/add-gcc-compiler-to-xcode-6/
If you have a custom gcc then you would need to change the paths around etc but the plugin should work.
I want to write an own c/c++ IDE with syntax-check etc. And of course I need a compiler-functionality. For this I want to use gcc, I think it is a good option, isn't it? The IDE should not call a gcc-binary to compile, it should include the gcc source code, because after compiling the IDE I want a stay alone executable.
So my question: Is there sth like a tutorial or a good hint how to realize this?
btw it's for Mac, I'll write the IDE with XCode
Thank you!
Use LLVM's Clang and its libClang API, it's built for this purpose. GCC is not made to be used as a library.
You might develop a plugin for GCC, or a GCC MELT extension. But it could be that on MacOSX GCC plugins are not supported yet. You might also look into GCCSense which might fill some of your goals (but I never used it).