build MLX, Cmlx via xcodeproj as a framework

tests passing with ml-explore/mlx#2702 locally applied

expose C++ API

Author: davidkoski

.gitignore

@@ -41,7 +41,6 @@ playground.xcworkspace
 Packages/
 Package.pins
 Package.resolved
-*.xcodeproj
 #
 # Xcode automatically generates this directory with a .xcworkspacedata file and xcuserdata
 # hence it is not needed unless you have added a package configuration file to your project

README.xcodeproj.md

@@ -0,0 +1,18 @@
+See `xcode/MLX.xcodeproj`.
+
+# Cmlx
+
+This is set up to build roughly how Package.swift builds.
+
+- Look at Project -> Cmlx -> Build Phases
+- remove all Project headers
+- remove all Copy Bundle Resources
+- remove any files that should not be built from the Target membership, e.g the items in `exclude`
+
+Public headers are in `include-framework` and this is managed by tools/update-mlx
+
+Settings, including header search paths are in xcode/xcconfig.
+
+# MLX, etc.
+
+These are just normal frameworks that link to Cmlx and others as needed.  The source files are all swift and there are no special settings needed.

Source/Cmlx/include-framework/Cmlx.h

@@ -0,0 +1,36 @@
+#include <Cmlx/mlx-c-mlx.h>
+#include <Cmlx/mlx-c-transforms_impl.h>
+#include <Cmlx/mlx-c-linalg.h>
+#include <Cmlx/mlx-c-fast.h>
+
+#include <Cmlx/mlx-array.h>
+#include <Cmlx/mlx-backend-cuda-cuda.h>
+#include <Cmlx/mlx-backend-gpu-available.h>
+#include <Cmlx/mlx-backend-metal-metal.h>
+#include <Cmlx/mlx-compile.h>
+#include <Cmlx/mlx-device.h>
+#include <Cmlx/mlx-distributed-distributed.h>
+#include <Cmlx/mlx-distributed-ops.h>
+#include <Cmlx/mlx-einsum.h>
+#include <Cmlx/mlx-export.h>
+#include <Cmlx/mlx-fast.h>
+#include <Cmlx/mlx-fft.h>
+#include <Cmlx/mlx-io.h>
+#include <Cmlx/mlx-linalg.h>
+#include <Cmlx/mlx-memory.h>
+#include <Cmlx/mlx-ops.h>
+#include <Cmlx/mlx-random.h>
+#include <Cmlx/mlx-stream.h>
+#include <Cmlx/mlx-transforms.h>
+#include <Cmlx/mlx-utils.h>
+#include <Cmlx/mlx-version.h>
+#include <Cmlx/mlx-allocator.h>
+#include <Cmlx/mlx-dtype.h>
+#include <Cmlx/mlx-event.h>
+#include <Cmlx/mlx-small_vector.h>
+#include <Cmlx/mlx-types-complex.h>
+#include <Cmlx/mlx-types-half_types.h>
+#include <Cmlx/mlx-types-bf16.h>
+#include <Cmlx/mlx-io-load.h>
+#include <Cmlx/mlx-export_impl.h>
+#include <Cmlx/mlx-threadpool.h>

Source/Cmlx/include-framework/mlx-allocator.h

@@ -0,0 +1,54 @@
+#ifdef __cplusplus
+// Copyright © 2023 Apple Inc.
+
+#pragma once
+
+#include <cstdlib>
+
+namespace mlx::core::allocator {
+
+// Simple wrapper around buffer pointers
+// WARNING: Only Buffer objects constructed from and those that wrap
+//          raw pointers from mlx::allocator are supported.
+class Buffer {
+ private:
+  void* ptr_;
+
+ public:
+  Buffer(void* ptr) : ptr_(ptr) {};
+
+  // Get the raw data pointer from the buffer
+  void* raw_ptr();
+
+  // Get the buffer pointer from the buffer
+  const void* ptr() const {
+    return ptr_;
+  };
+  void* ptr() {
+    return ptr_;
+  };
+};
+
+Buffer malloc(size_t size);
+
+void free(Buffer buffer);
+
+class Allocator {
+  /** Abstract base class for a memory allocator. */
+ public:
+  virtual Buffer malloc(size_t size) = 0;
+  virtual void free(Buffer buffer) = 0;
+  virtual size_t size(Buffer buffer) const = 0;
+
+  Allocator() = default;
+  Allocator(const Allocator& other) = delete;
+  Allocator(Allocator&& other) = delete;
+  Allocator& operator=(const Allocator& other) = delete;
+  Allocator& operator=(Allocator&& other) = delete;
+  virtual ~Allocator() = default;
+};
+
+Allocator& allocator();
+
+} // namespace mlx::core::allocator
+#endif