Add iOS examples

.bazelci/presubmit.yml

@@ -359,6 +359,12 @@ tasks:
     working_directory: examples/android
     build_targets:
       - "//:android_app"
+  ios_examples:
+    name: iOS Examples
+    platform: macos
+    working_directory: examples/ios
+    build_targets:
+      - "//..."
 
 buildifier:
   version: latest

examples/.bazelignore

@@ -1,3 +1,4 @@
 android
 cargo_manifest_dir/external_crate
 crate_universe
+ios

examples/ios/.gitignore

@@ -0,0 +1 @@
+/bazel-*

examples/ios/BUILD.bazel

@@ -0,0 +1,92 @@
+load("@build_bazel_rules_apple//apple:ios.bzl", "ios_application")
+load("@build_bazel_rules_apple//apple:macos.bzl", "macos_application")
+load("@rules_cc//cc:defs.bzl", "cc_library", "objc_library")
+load("@rules_rust//rust:defs.bzl", "rust_library")
+
+cc_library(
+    name = "allocator_library",
+    srcs = ["allocator_library.cc"],
+    tags = ["manual"],
+)
+
+rust_library(
+    name = "rust_lib",
+    srcs = ["demo.rs"],
+    edition = "2018",
+    tags = ["manual"],
+    deps = [":allocator_library"],
+)
+
+# TODO: Remove this once rules_rust doesn't support bazel 5.x
+cc_library(
+    name = "shim",
+    tags = ["manual"],
+    deps = [":rust_lib"],
+)
+
+objc_library(
+    name = "main_lib",
+    srcs = ["main_lib.m"],
+    tags = ["manual"],
+    deps = [":shim"],
+)
+
+ios_application(
+    name = "ios_app",
+    bundle_id = "com.example.iosapp",
+    families = ["iphone"],
+    infoplists = ["Info.plist"],
+    minimum_os_version = "13.0",
+    deps = [":main_lib"],
+)
+
+macos_application(
+    name = "macos_app",
+    bundle_id = "com.example.macosapp",
+    infoplists = ["Info.plist"],
+    minimum_os_version = "10.15",
+    deps = [":main_lib"],
+)
+
+platform(
+    name = "macos_x86_64",
+    constraint_values = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:macos",
+    ],
+)
+
+platform(
+    name = "macos_arm64",
+    constraint_values = [
+        "@platforms//cpu:arm64",
+        "@platforms//os:macos",
+    ],
+)
+
+platform(
+    name = "ios_x86_64",
+    constraint_values = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:ios",
+        "@build_bazel_apple_support//constraints:simulator",
+    ],
+)
+
+platform(
+    name = "ios_sim_arm64",
+    constraint_values = [
+        "@platforms//cpu:arm64",
+        "@platforms//os:ios",
+        "@build_bazel_apple_support//constraints:simulator",
+    ],
+)
+
+platform(
+    name = "ios_arm64",
+    constraint_values = [
+        "@platforms//cpu:arm64",
+        "@platforms//os:ios",
+        "@build_bazel_apple_support//constraints:device",
+    ],
+)

examples/ios/Info.plist

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+	<key>CFBundleVersion</key>
+	<string>1.0</string>
+	<key>ITSAppUsesNonExemptEncryption</key>
+	<false/>
+	<key>LSRequiresIPhoneOS</key>
+	<true/>
+	<key>UILaunchStoryboardName</key>
+	<string>LaunchScreen</string>
+	<key>UIRequiredDeviceCapabilities</key>
+	<array>
+		<string>arm64</string>
+	</array>
+	<key>UIStatusBarHidden</key>
+	<false/>
+	<key>UIStatusBarStyle</key>
+	<string>UIStatusBarStyleDefault</string>
+</dict>
+</plist>

examples/ios/WORKSPACE.bazel

@@ -0,0 +1,50 @@
+workspace(name = "ios_examples")
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+http_archive(
+    name = "build_bazel_rules_apple",
+    sha256 = "a19cf84dd060eda50be9ba5b0eca88377e0306ffbc1cc059df6a6947e48ac61a",
+    url = "https://github.com/bazelbuild/rules_apple/releases/download/1.1.1/rules_apple.1.1.1.tar.gz",
+)
+
+load(
+    "@build_bazel_rules_apple//apple:repositories.bzl",
+    "apple_rules_dependencies",
+)
+
+apple_rules_dependencies()
+
+load(
+    "@build_bazel_rules_swift//swift:repositories.bzl",
+    "swift_rules_dependencies",
+)
+
+swift_rules_dependencies()
+
+load(
+    "@build_bazel_apple_support//lib:repositories.bzl",
+    "apple_support_dependencies",
+)
+
+apple_support_dependencies()
+
+# Users of `rules_rust` will commonly be unable to load it
+# using a `local_repository`. Instead, to setup the rules,
+# please see https://bazelbuild.github.io/rules_rust/#setup
+local_repository(
+    name = "rules_rust",
+    path = "../..",
+)
+
+load("@rules_rust//rust:repositories.bzl", "rules_rust_dependencies", "rust_register_toolchains")
+
+rules_rust_dependencies()
+
+rust_register_toolchains(
+    edition = "2018",
+    extra_target_triples = [
+        "aarch64-apple-ios-sim",
+        "x86_64-apple-ios",
+    ],
+)

examples/ios/allocator_library.cc

@@ -0,0 +1,52 @@
+#include <stdint.h>
+
+// This file has some exciting magic to get Rust code linking in a cc_binary.
+// The Rust compiler generates some similar symbol aliases when it links, so we
+// have to do it manually. We mark all our symbols as weak so that linking this
+// via Rust tooling to produce a binary with a Rust main works.
+//
+// It is intended to be used in rust_toolchain.allocator_library.
+//
+// https://github.com/rust-lang/rust/blob/master/library/alloc/src/alloc.rs
+// and https://github.com/rust-lang/rust/blob/master/library/std/src/alloc.rs
+// are the best source of docs I've found on these functions and variables.
+// https://doc.rust-lang.org/std/alloc/index.html talks about how this is
+// intended to be used.
+//
+// Also note
+// https://rust-lang.github.io/unsafe-code-guidelines/layout/scalars.html for
+// the sizes of the various integer types.
+//
+// This file strongly assumes that the default allocator is used. It will
+// not work with any other allocated switched in via `#[global_allocator]`.
+
+// New feature as of https://github.com/rust-lang/rust/pull/88098.
+__attribute__((weak)) uint8_t __rust_alloc_error_handler_should_panic = 0;
+
+extern "C" uint8_t *__rdl_alloc(uintptr_t size, uintptr_t align);
+extern "C" __attribute__((weak))
+uint8_t *__rust_alloc(uintptr_t size, uintptr_t align) {
+  return __rdl_alloc(size, align);
+}
+extern "C" void __rdl_dealloc(uint8_t *ptr, uintptr_t size, uintptr_t align);
+extern "C" __attribute__((weak))
+void __rust_dealloc(uint8_t *ptr, uintptr_t size, uintptr_t align) {
+  __rdl_dealloc(ptr, size, align);
+}
+extern "C" uint8_t *__rdl_realloc(uint8_t *ptr, uintptr_t old_size, uintptr_t align,
+                       uintptr_t new_size);
+extern "C" __attribute__((weak))
+uint8_t *__rust_realloc(uint8_t *ptr, uintptr_t old_size, uintptr_t align,
+                        uintptr_t new_size) {
+  return __rdl_realloc(ptr, old_size, align, new_size);
+}
+extern "C" uint8_t *__rdl_alloc_zeroed(uintptr_t size, uintptr_t align);
+extern "C" __attribute__((weak))
+uint8_t *__rust_alloc_zeroed(uintptr_t size, uintptr_t align) {
+  return __rdl_alloc_zeroed(size, align);
+}
+extern "C" void __rdl_oom(uintptr_t size, uintptr_t align);
+extern "C" __attribute__((weak))
+void __rust_alloc_error_handler(uintptr_t size, uintptr_t align) {
+  __rdl_oom(size, align);
+}

examples/ios/demo.rs

@@ -0,0 +1,9 @@
+#[no_mangle]
+pub extern fn print_something_from_rust() {
+    println!("Ferris says hello!");
+}
+
+#[no_mangle]
+pub extern fn get_a_value_from_rust() -> i32 {
+    42
+}

examples/ios/main_lib.m

@@ -0,0 +1,11 @@
+#include <stdio.h>
+
+// Instead of doing this manually https://github.com/dtolnay/cxx could be used for complex examples
+extern int32_t get_a_value_from_rust(void);
+extern void print_something_from_rust(void);
+
+int main() {
+  print_something_from_rust();
+  printf("Some value from rust: %d\n", get_a_value_from_rust());
+  return 0;
+}

examples/ios/platform_mappings

@@ -0,0 +1,21 @@
+# https://github.com/bazelbuild/rules_apple/issues/1658
+flags:
+  --cpu=darwin_x86_64
+  --apple_platform_type=macos
+    //:macos_x86_64
+
+  --cpu=darwin_arm64
+  --apple_platform_type=macos
+    //:macos_arm64
+
+  --cpu=ios_x86_64
+  --apple_platform_type=ios
+    //:ios_x86_64
+
+  --cpu=ios_sim_arm64
+  --apple_platform_type=ios
+    //:ios_sim_arm64
+
+  --cpu=ios_arm64
+  --apple_platform_type=ios
+    //:ios_arm64