add support for metal

build.zig

@@ -18,11 +18,25 @@ pub fn build(b: *std.Build) !void {
     lib.linker_allow_shlib_undefined = true;
 
     // ggml
-    // lib.linkFramework("Accelerate");
-    // lib.defineCMacroRaw("GGML_USE_ACCELERATE=1");
     lib.addIncludePath(.{ .path = "deps/ggml/include/ggml" });
+    lib.addIncludePath(.{ .path = "deps/ggml/src" });
     lib.addCSourceFile(.{ .file = .{ .path = "deps/ggml/src/ggml.c" }, .flags = &.{ "-std=c11", "-pthread" } });
 
+    // Use Metal on macOS
+    if (target.getOsTag() == .macos) {
+        lib.defineCMacroRaw("GGML_USE_METAL");
+        lib.defineCMacroRaw("GGML_METAL_NDEBUG");
+        lib.addCSourceFiles(&.{"deps/ggml/src/ggml-metal.m"}, &.{"-std=c11"});
+        lib.linkFramework("Foundation");
+        lib.linkFramework("Metal");
+        lib.linkFramework("MetalKit");
+        lib.linkFramework("MetalPerformanceShaders");
+
+        // copy the *.metal file so that it can be loaded at runtime
+        const copy_metal_step = b.addInstallLibFile(.{ .path = "deps/ggml/src/ggml-metal.metal" }, "ggml-metal.metal");
+        b.getInstallStep().dependOn(&copy_metal_step.step);
+    }
+
     const napigen = b.createModule(.{ .source_file = .{ .path = "deps/napigen/napigen.zig" } });
     lib.addModule("napigen", napigen);
 

src/ggml.zig

@@ -1,10 +1,15 @@
 const std = @import("std");
+const builtin = @import("builtin");
 
 const ggml = @cImport({
     // NEON is supported, this is just for the @cImport
     @cUndef("__ARM_NEON");
     @cDefine("GGML_ASSERT(x)", "(x || abort())");
     @cInclude("ggml.h");
+
+    if (builtin.os.tag == .macos) {
+        @cInclude("ggml-metal.h");
+    }
 });
 
 // re-export everything

src/main.zig

@@ -1,4 +1,5 @@
 const std = @import("std");
+const builtin = @import("builtin");
 const napigen = @import("napigen");
 const ggml = @import("ggml.zig");
 const safetensors = @import("safetensors.zig");
@@ -12,6 +13,10 @@ comptime {
 }
 
 fn initModule(js: *napigen.JsContext, exports: napigen.napi_value) napigen.Error!napigen.napi_value {
+    if (builtin.os.tag == .macos) {
+        _ = ggml.ggml_metal_init(1);
+    }
+
     @setEvalBranchQuota(100_000);
     inline for (comptime std.meta.declarations(ggml)) |d| {
         if (comptime !std.ascii.startsWithIgnoreCase(d.name, "ggml_") or