Is it possible to conditionally compile for a specific target triple? I’m having issues with excluding the x86_64-rumprun-netbsd target without simply excluding netbsd with a #[cfg].
You want to use the target_vendor configuration, which has a value for rumprun as described in this PR. In general, you can use any of the target vendors from this page, as described in this PR.
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We want to use a single gcc for multiple targets. Is it possible to build from source for supporting multiple targets?
The answer is no, you cannot do this with gcc. You can use some cross compilers to achieve this goal.
But if you really need to do this, you can use clang compiler. Here is the link:
https://clang.llvm.org/docs/CrossCompilation.html
Adding answer to the Gabriel. All architecture what you mentioned above are different CPU's.
It's not possible to generate different binaries with the gcc compiler.
You need to have different toolchains for each compiler that produce corresponding compatible code.
x86, PPC and ARM are the different machines. You cant run the code which you build using host toolchains.
Below provided reference use machine specific toolchains not host-gcc. This is very cumbersome and not straightforward approach.
For curiosity, you can have a look at the bitbake, parallel build of multiple machines
I'll also add that to have a useful toolchain you also need to build other components besides GCC. Components like an assembler and linker (from binutils for example) and a C library (e.g. glibc, musl, newlib etc). Each such component needs to be configured for a specific target
I'm trying to include multiple Metal shaders in my Xcode project which have different language versions, but I'm unable to figure out how to do it.
I'm trying to do this, so I can support the latest features when available and drop back when not.
In the project's settings I can only find a general specifier for the Metal language revision. I also can't find anything in the MSL reference manual to specify it inside the file.
Is this even possible? If so, how?
Thanks in advance.
In Xcode, go to the Build Phases for the target which builds your app. Disclose the compile sources. Select a .metal file. Double-click in the right-hand Compiler Flags column to edit it. Enter -std=osx-metal1.2 or similar. That specific shader source file will be compiled with that language.
I found this compiler flag by comparing the build transcripts of builds with various settings for the target-wide build setting.
How can I ensure that object files compiled for one hardware target will not be used for a different hardware target that needs to be compiled differently?
I am using the GNU ARM Embedded Toolchain while I am learning about embedded development. I already have a couple of development boards (with STM32F0 and STM32F4 processors), and plan to make my own boards in the future. I want to have several iterations of hardware using a common software repository.
Obviously I will have multiple targets in my Makefile, invoking the appropriate defines and compiler flags for each platform, and perhaps a make all to build for all platforms at once. As I understand it, make is an incremental build system that only re-compiles object code (*.o) files if the source file has been changed, it won't recompile if I have use different defines and options, and the wrong object code will be passed to the linker.
It seems that I could diligently make clean when switching between different targets, but that would rely on the human action and could produce bad builds if I forgot, and could not be used for a make all that produces multiple binaries for their respective hardware.
Edit Notes: Per feedback comments, I have shorted and rearranged to make the question more clear and objective. I'm not asking generically how to use Make, but rather how to prevent, say mylib.o being compiled for an STM32F0 and then later being re-used in a build for an STM32F4.
I am curious about alternative tools, and welcome discussion in the comments, but this question is specific to GNU Make.
To avoid the need for a clean build between targets, it is necessary for each target to have separate build directories in order that the target dependencies are independent and specifically generated using the appropriate tool chain and build switches etc.
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 have C project of a library (using CDT). Configurations for both static and dynamic linking for several platforms. Several examples of the library usage is also included in the project. What is the best way to build these examples with the library? If I would like to build both the library and examples (linking the library just built) in one configuration?
I suppose I have to use custom makefile. Do I have to create makefile for the whole project (several of them, one for each platform), or is there any way how to include examples makefile to the automatic one?
Each example has only one source file, so the only things I need to do in my makefile are to determine which compiler is used, add some flags and link with the library which was built (I would include the make examples command as the post-build step).
As I didn't find any solution for this, I use custom makefile for the whole build. I also found a nice advice somewhere: if you want advanced build functions, use advanced build system.