SERVER-105745: Enable the Apple OSS LLVM Clang as default compiler for Apple Builds. (#36982)

GitOrigin-RevId: 8e7cc041f25fff8ed1e47e77bccef1fdfdd92c92

.bazelrc

@@ -152,7 +152,7 @@ common --flag_alias=dbg_level=//bazel/config:dbg_level
 common --flag_alias=mongo_toolchain_version=//bazel/config:mongo_toolchain_version
 common --flag_alias=simple_build_id=//bazel/config:simple_build_id
 common --flag_alias=create_dwp=//bazel/config:create_dwp
-common --flag_alias=local_clang_compiler=//bazel/config:local_clang_compiler
+common --flag_alias=use_apple_clang=//bazel/config:apple_clang
 
 #############################################################################################################################
 # BUILD 'PROFILES' - this is the area to set up configurations of flags to be used by developers.

bazel/config/BUILD.bazel

@@ -26,7 +26,6 @@ load(
     "libunwind",
     "linker",
     "linkstatic",
-    "local_clang_compiler",
     "lsan",
     "mongo_toolchain_version",
     "msan",
@@ -92,15 +91,15 @@ config_setting(
     },
 )
 
-local_clang_compiler(
-    name = "local_clang_compiler",
+bool_flag(
+    name = "apple_clang",
     build_setting_default = False,
 )
 
 config_setting(
-    name = "use_local_clang_compiler",
+    name = "use_apple_clang",
     flag_values = {
-        "//bazel/config:local_clang_compiler": "True",
+        ":apple_clang": "true",
     },
 )
 

bazel/config/configs.bzl

@@ -23,20 +23,6 @@ compiler_type = rule(
     build_setting = config.string(flag = True),
 )
 
-# =============
-# compiler_type
-# =============
-
-local_clang_compiler_provider = provider(
-    doc = "use the local clang compiler",
-    fields = ["enabled"],
-)
-
-local_clang_compiler = rule(
-    implementation = lambda ctx: local_clang_compiler_provider(enabled = ctx.build_setting_value),
-    build_setting = config.bool(flag = True),
-)
-
 # =========
 # mongo_toolchain_version
 # =========

bazel/toolchains/cc/mongo_apple/mongo_apple_toolchain.BUILD.tmpl

@@ -14,8 +14,8 @@ package(default_visibility = ["//visibility:public"])
             "@platforms//cpu:" + cpu,
         ],
         toolchain = select({
-            "@//bazel/config:use_local_clang_compiler": "@mongo_apple_brew_llvm_toolchain_config//:cc-compiler-" + apple_arch,
-            "@//conditions:default": "@mongo_apple_toolchain_config//:cc-compiler-" + apple_arch,
+            "@//bazel/config:use_apple_clang": "@mongo_apple_toolchain_config//:cc-compiler-" + apple_arch,
+            "@//conditions:default": "@mongo_apple_brew_llvm_toolchain_config//:cc-compiler-" + apple_arch,
         }),
         toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
     )

docs/building.md

@@ -9,7 +9,7 @@ To build MongoDB, you will need:
 - A modern C++ compiler capable of compiling C++20. One of the following is required:
   - GCC 14.2 or newer
   - Clang 19.1 or newer
-  - Apple XCode 14 or newer
+  - Apple XCode 16.4 or newer
   - Visual Studio 2022 version 17.0 or newer (See Windows section below for details)
 - On Linux and macOS, the libcurl library and header is required. MacOS includes libcurl.
   - Fedora/RHEL - `dnf install libcurl-devel`
@@ -95,4 +95,8 @@ To install dependencies on Debian or Ubuntu systems:
 
 ## OS X
 
-Install Xcode 14.0 or newer.
+Install Xcode 16.4 or newer. Make sure macOS 15.5 platform
+is installed.
+
+Install llvm and lld, version 19 from brew:
+brew install llvm@19 lld@19

etc/evergreen_yml_components/variants/macos/test_dev_master_branch_only.yml

@@ -13,7 +13,9 @@ buildvariants:
     expansions:
       compile_variant: *enterprise-macos-arm64
       test_flags: --excludeWithAnyTags=incompatible_with_macos,requires_gcm
-      bazel_compile_flags: --developer_dir=/Applications/Xcode15.app
+      bazel_compile_flags: >-
+        --developer_dir=/Applications/Xcode15.app
+        --use_apple_clang
       resmoke_jobs_max: 6
     tasks:
       - name: compile_test_serial_TG

etc/evergreen_yml_components/variants/macos/test_release.yml

@@ -22,6 +22,7 @@ buildvariants:
       bazel_compile_flags: >-
         --build_enterprise=False
         --developer_dir=/Applications/Xcode15.app
+        --use_apple_clang
       resmoke_jobs_max: 6
       compile_variant: macos-arm64
     tasks:
@@ -45,7 +46,9 @@ buildvariants:
       push_bucket: downloads.10gen.com
       push_name: macos
       push_arch: arm64-enterprise
-      bazel_compile_flags: --developer_dir=/Applications/Xcode15.app
+      bazel_compile_flags: >-
+        --developer_dir=/Applications/Xcode15.app
+        --use_apple_clang
       resmoke_jobs_max: 6
       compile_variant: enterprise-macos-arm64
     tasks:
@@ -71,6 +74,7 @@ buildvariants:
       bazel_compile_flags: >-
         --build_enterprise=False
         --developer_dir=/Applications/Xcode15.app
+        --use_apple_clang
       resmoke_jobs_max: 6
       compile_variant: macos
     tasks:
@@ -94,7 +98,9 @@ buildvariants:
       push_bucket: downloads.10gen.com
       push_name: macos
       push_arch: x86_64-enterprise
-      bazel_compile_flags: --developer_dir=/Applications/Xcode15.app
+      bazel_compile_flags: >-
+        --developer_dir=/Applications/Xcode15.app
+        --use_apple_clang
       resmoke_jobs_max: 6
       compile_variant: enterprise-macos
     tasks:
@@ -118,9 +124,7 @@ buildvariants:
       push_bucket: downloads.mongodb.org
       push_name: macos
       push_arch: arm64
-      bazel_compile_flags: >-
-        --build_enterprise=False
-        --local_clang_compiler
+      bazel_compile_flags: --build_enterprise=False
       resmoke_jobs_max: 6
       compile_variant: macos-arm64
     tasks:
@@ -144,9 +148,7 @@ buildvariants:
       push_bucket: downloads.mongodb.org
       push_name: macos
       push_arch: x86_64
-      bazel_compile_flags: >-
-        --build_enterprise=False
-        --local_clang_compiler
+      bazel_compile_flags: --build_enterprise=False
       resmoke_jobs_max: 6
       compile_variant: macos
     tasks:
@@ -171,7 +173,6 @@ buildvariants:
       push_bucket: downloads.10gen.com
       push_name: macos
       push_arch: x86_64-enterprise
-      bazel_compile_flags: --local_clang_compiler
       resmoke_jobs_max: 6
       compile_variant: enterprise-macos
     tasks:
@@ -196,7 +197,6 @@ buildvariants:
       push_bucket: downloads.10gen.com
       push_name: macos
       push_arch: arm64-enterprise
-      bazel_compile_flags: --local_clang_compiler
       resmoke_jobs_max: 6
       compile_variant: enterprise-macos-arm64
     tasks:

etc/evergreen_yml_components/variants/sanitizer/test_dev_master_branch_only.yml

@@ -341,6 +341,7 @@ buildvariants:
         --opt=on
         --build_enterprise=False
         --developer_dir=/Applications/Xcode15.app
+        --use_apple_clang
     tasks:
       - name: compile_test_serial_TG
       - name: run_unit_tests_TG
@@ -368,6 +369,7 @@ buildvariants:
         --dbg=True
         --opt=on
         --developer_dir=/Applications/Xcode15.app
+        --use_apple_clang
       resmoke_jobs_max: 6
     tasks:
       - name: compile_test_serial_TG
@@ -398,7 +400,6 @@ buildvariants:
         --dbg=True
         --opt=on
         --build_enterprise=False
-        --local_clang_compiler
     tasks:
       - name: compile_test_serial_TG
       - name: run_unit_tests_TG
@@ -425,7 +426,6 @@ buildvariants:
       bazel_compile_flags: >-
         --dbg=True
         --opt=on
-        --local_clang_compiler
       resmoke_jobs_max: 6
     tasks:
       - name: compile_test_serial_TG