Update WORKSPACE to use a prebuilt host toolchain

Change-Id: Iefc7ae6f02bf5ce22351da9cc1717f68ab2ae9ca
Reviewed-on: https://fuchsia-review.googlesource.com/c/template/driver/+/907969
Reviewed-by: Jiaming Li <lijiaming@google.com>

.bazelrc

diff --git a/.bazelrc b/.bazelrc
new file mode 100644
index 0000000..1228d5d
--- /dev/null
+++ b/.bazelrc
@@ -0,0 +1,7 @@
+# Copyright 2023 The Fuchsia Authors. All rights reserved
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file
+
+# Leave this line at the top of this file. It will pull in various useful defaults
+# Any changes after this line will take precedence
+try-import %workspace%/third_party/fuchsia-infra-bazel-rules/config/common_config.bazelrc

WORKSPACE.bazel

diff --git a/WORKSPACE.bazel b/WORKSPACE.bazel
index 5c77d00..52a983b 100644
--- a/WORKSPACE.bazel
+++ b/WORKSPACE.bazel
@@ -4,6 +4,7 @@
 
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
+# Set up bazel skylib and its dependencies
 http_archive(
     name = "bazel_skylib",
     sha256 = "f7be3474d42aae265405a592bb7da8e171919d74c16f082a5457840f06054728",
@@ -17,6 +18,8 @@
 
 bazel_skylib_workspace()
 
+# The fuchsia_infra repository provides rules which allow us to work inside of
+# fuchsia's infrastructure.
 local_repository(
     name = "fuchsia_infra",
     path = "third_party/fuchsia-infra-bazel-rules",
@@ -27,10 +30,15 @@
 
 fuchsia_infra_workspace()
 
+# Create a common cipd binary which will be used to download prebuilts
 cipd_tool_repository(
     name = "cipd_tool",
 )
 
+# Fetch the Fuchsia SDK and register it as a repostiory. The version that is
+# used is stored in the manifests/bazel_sdk.ensure file so it can be updated by
+# our autoroller infrastructure. When the version changes bazel will fetch the
+# new prebuilts.
 cipd_repository(
     name = "fuchsia_sdk",
     cipd_bin = "@cipd_tool//:cipd",
@@ -44,6 +52,7 @@
 
 rules_fuchsia_deps()
 
+# The fuchsia toolchain contains tools like ffx and fidlc.
 register_toolchains("@fuchsia_sdk//:fuchsia_toolchain_sdk")
 
 load(
@@ -51,6 +60,7 @@
     "fuchsia_clang_repository",
 )
 
+# Set up our clang repository.
 fuchsia_clang_repository(
     name = "fuchsia_clang",
     cipd_bin = "@cipd_tool//:cipd",
@@ -60,8 +70,17 @@
 
 load("@fuchsia_clang//:defs.bzl", "register_clang_toolchains")
 
+# Register a clang toolchain which will be used to compile fuchsia targets
 register_clang_toolchains()
 
+load("@fuchsia_infra//infra:host_toolchains.bzl", "configure_fuchsia_clang_host_toolchain")
+
+# Configure a host toolchain for local execution. This is not used to compile
+# fuchsia targets but is made available so we don't try to access the host gcc
+# which is not available in infrastructure builds. This call must happen after
+# you create a fuchsia_clang repository.
+configure_fuchsia_clang_host_toolchain(name = "host_clang_toolchain")
+
 # gTest.
 local_repository(
     name = "com_google_googletest",

manifests/bazel_sdk.ensure

diff --git a/manifests/bazel_sdk.ensure b/manifests/bazel_sdk.ensure
index 62840d3..7a7cb18 100644
--- a/manifests/bazel_sdk.ensure
+++ b/manifests/bazel_sdk.ensure
@@ -1,4 +1,4 @@
 $ResolvedVersions bazel_sdk.resolved
 $VerifiedPlatform linux-amd64 mac-amd64
-fuchsia/sdk/core/fuchsia-bazel-rules/${os=linux}-${arch} version:14.20230811.1.1
-fuchsia/sdk/core/fuchsia-bazel-rules/${os=mac}-amd64 version:14.20230811.1.1
+fuchsia/sdk/core/fuchsia-bazel-rules/${os=linux}-${arch} version:14.20230825.3.1
+fuchsia/sdk/core/fuchsia-bazel-rules/${os=mac}-amd64 version:14.20230825.3.1

manifests/bazel_sdk.resolved

diff --git a/manifests/bazel_sdk.resolved b/manifests/bazel_sdk.resolved
index 933918a..c1ae053 100644
--- a/manifests/bazel_sdk.resolved
+++ b/manifests/bazel_sdk.resolved
@@ -2,9 +2,9 @@
 # Do not modify manually. All changes will be overwritten.
 
 fuchsia/sdk/core/fuchsia-bazel-rules/linux-amd64
-	version:14.20230811.1.1
-	FMoDn9X0Ni9ZVynt7XfRFRkD5i1sEFrFLMwu0D6tUpoC
+	version:14.20230825.3.1
+	-8e0YUn0dXZzKSPmEJLVtzk2lijh1zC9A1kny0WwWEsC
 
 fuchsia/sdk/core/fuchsia-bazel-rules/mac-amd64
-	version:14.20230811.1.1
-	ZE9Fp0kusiHYaCzkDnTTO4ydWEodKlMdpbhSUbTfpLIC
+	version:14.20230825.3.1
+	d16iCfvEDT919buOe054wlxk0gATLK_GescQCMhrlaEC

platform_mappings

diff --git a/platform_mappings b/platform_mappings
new file mode 120000
index 0000000..d4586be
--- /dev/null
+++ b/platform_mappings
@@ -0,0 +1 @@
+third_party/fuchsia-infra-bazel-rules/config/fuchsia_platform_mappings
\ No newline at end of file

third_party/fuchsia-infra-bazel-rules

diff --git a/third_party/fuchsia-infra-bazel-rules b/third_party/fuchsia-infra-bazel-rules
index cee346b..d2a04e2 160000
--- a/third_party/fuchsia-infra-bazel-rules
+++ b/third_party/fuchsia-infra-bazel-rules
@@ -1 +1 @@
-Subproject commit cee346b317bea2a1f51cb1fc07894b2af3e5ca53
+Subproject commit d2a04e20e4ad6ece319720bf2f9016227c7a36fe