Simple program to compile a given Metal file into a device specific dynamic Metal library (GPU code)

gpu_compiler.m

// clang gpu_compiler.m -fobjc-arc -fmodules -mmacosx-version-min=11.0 -framework Foundation -framework CoreGraphics -o gpu_compiler
#import <Foundation/Foundation.h>
#import <Metal/Metal.h>

void compile_to_gpu_code(id<MTLDevice> device, NSString *programString, NSString *destinationPath) {
    NSError *error;

    MTLCompileOptions *options = [MTLCompileOptions new];
    options.libraryType = MTLLibraryTypeDynamic;
    options.installName = [NSString stringWithFormat:@"@executable_path/userCreatedDylib.metallib"];

    id<MTLLibrary> lib = [device newLibraryWithSource:programString
                                               options:options
                                                 error:&error];

    if(!lib && error)
    {
        NSLog(@"Error compiling library from source: %@", error);
        return;
    }
    
    id<MTLDynamicLibrary> dynamicLib = [device newDynamicLibrary:lib
                                                            error:&error];
    if(!dynamicLib && error)
    {
        NSLog(@"Error creating dynamic library from source library: %@", error);
        return;
    }

    NSURL *destinationURL = [NSURL URLWithString:destinationPath];

    bool result = [dynamicLib serializeToURL:destinationURL error:&error];

    if (!result && error)
    {
        NSLog(@"Error serializing dynamic library: %@", error);
        return;
    }

    NSLog(@"Compilation done.");
}

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSError *error;
        
        id<MTLDevice> device = MTLCreateSystemDefaultDevice();

        NSString *sourcePath = [NSString stringWithUTF8String:argv[1]];
        NSString *destinationPath = [NSString stringWithUTF8String:argv[2]];

        NSString *source = [NSString stringWithContentsOfFile:sourcePath encoding:NSUTF8StringEncoding error:&error];

        compile_to_gpu_code(device, source, destinationPath);
    }
    return 0;
}