From cfd4b6d01e9ce1d915745d83a2f7553991ba020f Mon Sep 17 00:00:00 2001
From: Brentley Jones <github@brentleyjones.com>
Date: Tue, 1 Oct 2024 11:28:25 -0500
Subject: [PATCH] Add toolchains (#1321)

These can be used once we flip the ruleset to actual return the
toolchain type from `use_swift_toolchain()`.

Signed-off-by: Brentley Jones <github@brentleyjones.com>
---
 swift/internal/BUILD                       |  5 +-
 swift/internal/swift_autoconfiguration.bzl | 69 +++++++++++++++++++++-
 toolchains/BUILD                           |  4 ++
 3 files changed, 76 insertions(+), 2 deletions(-)
 create mode 100644 toolchains/BUILD

diff --git a/swift/internal/BUILD b/swift/internal/BUILD
index 8a1c4bd75..00b7702a4 100644
--- a/swift/internal/BUILD
+++ b/swift/internal/BUILD
@@ -202,7 +202,10 @@ bzl_library(
     name = "swift_autoconfiguration",
     srcs = ["swift_autoconfiguration.bzl"],
     visibility = ["//swift:__subpackages__"],
-    deps = ["//swift/internal:feature_names"],
+    deps = [
+        ":toolchain_utils",
+        "//swift/internal:feature_names",
+    ],
 )
 
 bzl_library(
diff --git a/swift/internal/swift_autoconfiguration.bzl b/swift/internal/swift_autoconfiguration.bzl
index 38a72019a..2f067b4f0 100644
--- a/swift/internal/swift_autoconfiguration.bzl
+++ b/swift/internal/swift_autoconfiguration.bzl
@@ -25,7 +25,7 @@ Skylib.
 """
 
 load(
-    "//swift/internal:feature_names.bzl",
+    ":feature_names.bzl",
     "SWIFT_FEATURE_CODEVIEW_DEBUG_INFO",
     "SWIFT_FEATURE_DEBUG_PREFIX_MAP",
     "SWIFT_FEATURE_EMIT_SWIFTDOC",
@@ -41,6 +41,7 @@ load(
     "SWIFT_FEATURE_USE_MODULE_WRAP",
     "SWIFT_FEATURE_USE_OLD_DRIVER",
 )
+load(":toolchain_utils.bzl", "SWIFT_TOOLCHAIN_TYPE")
 
 def _scratch_file(repository_ctx, temp_dir, name, content = ""):
     """Creates and returns a scratch file with the given name and content.
@@ -237,6 +238,10 @@ def _create_linux_toolchain(repository_ctx):
     repository_ctx.file(
         "BUILD",
         """
+load(
+    "@build_bazel_apple_support//configs:platforms.bzl",
+    "APPLE_PLATFORMS_CONSTRAINTS",
+)
 load(
     "@build_bazel_rules_swift//swift/toolchains:swift_toolchain.bzl",
     "swift_toolchain",
@@ -252,6 +257,21 @@ swift_toolchain(
     root = "{root}",
     version_file = "{version_file}",
 )
+
+[
+    toolchain(
+        name = "xcode-toolchain-" + arch + "-{cpu}",
+        exec_compatible_with = [
+            "@platforms//os:linux",
+            "@platforms//cpu:{cpu}",
+        ],
+        target_compatible_with = APPLE_PLATFORMS_CONSTRAINTS[arch],
+        toolchain = ":toolchain",
+        toolchain_type = "{toolchain_type}",
+        visibility = ["//visibility:public"],
+    )
+    for arch in APPLE_PLATFORMS_CONSTRAINTS.keys()
+]
 """.format(
             cpu = _normalized_linux_cpu(repository_ctx.os.arch),
             feature_list = ", ".join([
@@ -259,6 +279,7 @@ swift_toolchain(
                 for feature in feature_values
             ]),
             root = root,
+            toolchain_type = SWIFT_TOOLCHAIN_TYPE,
             version_file = version_file,
         ),
     )
@@ -279,6 +300,10 @@ def _create_xcode_toolchain(repository_ctx):
     repository_ctx.file(
         "BUILD",
         """
+load(
+    "@build_bazel_apple_support//configs:platforms.bzl",
+    "APPLE_PLATFORMS_CONSTRAINTS",
+)
 load(
     "@build_bazel_rules_swift//swift/toolchains:xcode_swift_toolchain.bzl",
     "xcode_swift_toolchain",
@@ -286,15 +311,37 @@ load(
 
 package(default_visibility = ["//visibility:public"])
 
+_OSX_DEVELOPER_PLATFORM_CPUS = [
+    "arm64",
+    "x86_64",
+]
+
 xcode_swift_toolchain(
     name = "toolchain",
     features = [{feature_list}],
 )
+
+[
+    toolchain(
+        name = "xcode-toolchain-" + arch + "-" + cpu,
+        exec_compatible_with = [
+            "@platforms//os:macos",
+            "@platforms//cpu:" + cpu,
+        ],
+        target_compatible_with = APPLE_PLATFORMS_CONSTRAINTS[arch],
+        toolchain = ":toolchain",
+        toolchain_type = "{toolchain_type}",
+        visibility = ["//visibility:public"],
+    )
+    for arch in APPLE_PLATFORMS_CONSTRAINTS.keys()
+    for cpu in _OSX_DEVELOPER_PLATFORM_CPUS
+]
 """.format(
             feature_list = ", ".join([
                 '"{}"'.format(feature)
                 for feature in feature_values
             ]),
+            toolchain_type = SWIFT_TOOLCHAIN_TYPE,
         ),
     )
 
@@ -345,6 +392,10 @@ def _create_windows_toolchain(repository_ctx):
     repository_ctx.file(
         "BUILD",
         """
+load(
+    "@build_bazel_apple_support//configs:platforms.bzl",
+    "APPLE_PLATFORMS_CONSTRAINTS",
+)
 load(
   "@build_bazel_rules_swift//swift/toolchains:swift_toolchain.bzl",
   "swift_toolchain",
@@ -364,11 +415,27 @@ swift_toolchain(
   tool_executable_suffix = ".exe",
   xctest_version = "{xctest_version}",
 )
+
+[
+    toolchain(
+        name = "windows-toolchain-" + arch + "-x86_64",
+        exec_compatible_with = [
+            "@platforms//os:windows",
+            "@platforms//cpu:x86_64",
+        ],
+        target_compatible_with = APPLE_PLATFORMS_CONSTRAINTS[arch],
+        toolchain = ":toolchain",
+        toolchain_type = "{toolchain_type}",
+        visibility = ["//visibility:public"],
+    )
+    for arch in APPLE_PLATFORMS_CONSTRAINTS.keys()
+]
 """.format(
             features = ", ".join(['"{}"'.format(feature) for feature in enabled_features] + ['"-{}"'.format(feature) for feature in disabled_features]),
             root = root,
             env = env,
             sdkroot = repository_ctx.os.environ["SDKROOT"].replace("\\", "/"),
+            toolchain_type = SWIFT_TOOLCHAIN_TYPE,
             xctest_version = xctest_version.stdout.rstrip(),
             version_file = version_file,
         ),
diff --git a/toolchains/BUILD b/toolchains/BUILD
new file mode 100644
index 000000000..c6d09a29f
--- /dev/null
+++ b/toolchains/BUILD
@@ -0,0 +1,4 @@
+toolchain_type(
+    name = "toolchain_type",
+    visibility = ["//visibility:public"],
+)