Implement Bazel Clang toolchain

.bazelrc

@@ -7,15 +7,8 @@ build:windows --enable_runfiles=true
 build --enable_platform_specific_config
 build --build_python_zip=false
 
-build:windows  --extra_execution_platforms=//:x64_windows-clang-cl
+build --features=c++23
-build:windows  --extra_toolchains=@local_config_cc//:cc-toolchain-x64_windows-clang-cl
+build --cxxopt=-Weverything
-
-build:linux    --repo_env=CC=clang
-
-build:windows  --cxxopt=-Xclang=-std=c++23
-build:linux    --cxxopt=-std=c++23
-
-build --cxxopt=-Wall
 build --cxxopt=-Wno-c++98-compat
 build --cxxopt=-Wno-c++98-compat-pedantic
 build --cxxopt=-Wno-pre-c++17-compat
@@ -28,21 +21,7 @@ build --cxxopt=-Wno-global-constructors
 build --cxxopt=-Wno-unsafe-buffer-usage
 build --cxxopt=-Wno-covered-switch-default
 build --cxxopt=-Wno-unused-command-line-argument
-
+build --cxxopt=-Wno-padded
-build:windows_san --config=windows
+build --cxxopt=-Wno-weak-vtables
-build:windows_san --copt=-fno-sanitize-ignorelist
-build:windows_san --copt=-fsanitize=address
-build:windows_san --copt=-fsanitize=undefined
-build:windows_san --copt=-fno-sanitize-recover=all
-build:windows_san --linkopt=clang_rt.asan_dynamic-x86_64.lib
-build:windows_san --linkopt=clang_rt.asan_dynamic_runtime_thunk-x86_64.lib
-
-build:linux_san --config=linux
-build:linux_san --copt=-fsanitize=address
-build:linux_san --linkopt=-fsanitize=address
-build:linux_san --copt=-fsanitize=undefined
-build:linux_san --copt=-fno-sanitize-recover=all
-build:linux_san --linkopt=-fsanitize=undefined
-build:linux_san --linkopt=-fsanitize-link-c++-runtime
 
 test --test_output=errors

BUILD.bazel

@@ -13,14 +13,3 @@ license(
     package_name = "ASL",
 )
 
-platform(
-    name = "x64_windows-clang-cl",
-    constraint_values = [
-        "@platforms//cpu:x86_64",
-        "@platforms//os:windows",
-        # @Todo(bazel) Bit weird to use a private thing.
-        # We used to use @bazel_tools//tools/cpp:clang-cl but it's deprecated
-        # in favor of... this?...
-        "@rules_cc//cc/private/toolchain:clang-cl",
-    ],
-)

MODULE.bazel

@@ -8,11 +8,18 @@ bazel_dep(name = "platforms", version = "0.0.11")
 bazel_dep(name = "rules_license", version = "1.0.0")
 
 bazel_dep(name = "rules_cc", version = "0.1.1")
-cc_configure = use_extension("@rules_cc//cc:extensions.bzl", "cc_configure_extension")
-use_repo(cc_configure, "local_config_cc")
 
 bazel_dep(name = "hedron_compile_commands", version = "0.1.0", dev_dependency = True)
 
 bazel_dep(name = "rules_python", version = "1.3.0")
 python = use_extension("@rules_python//python/extensions:python.bzl", "python")
 python.toolchain(python_version = "3.13", is_default = True)
+
+clang_toolchain = use_extension("//bazel/clang_toolchain:config_detection.bzl", "clang_toolchain")
+use_repo(clang_toolchain, "clang_toolchain")
+register_toolchains(
+    "@clang_toolchain//:windows_x86_64_toolchain_def",
+    "@clang_toolchain//:linux_x86_64_toolchain_def",
+    "@clang_toolchain//:linux_aarch64_toolchain_def",
+)
+

MODULE.bazel.lock

@@ -146,6 +146,22 @@
   },
   "selectedYankedVersions": {},
   "moduleExtensions": {
+    "//bazel/clang_toolchain:config_detection.bzl%clang_toolchain": {
+      "general": {
+        "bzlTransitiveDigest": "xXTcNvgp9bMnw/1ZKi1vOOoz139EHr8Hw3Ugd9+eos0=",
+        "usagesDigest": "CRr/eSLZQiKHqCq8MWfzhslrj4Mqar1310aEoa4BzJw=",
+        "recordedFileInputs": {},
+        "recordedDirentsInputs": {},
+        "envVariables": {},
+        "generatedRepoSpecs": {
+          "clang_toolchain": {
+            "repoRuleId": "@@//bazel/clang_toolchain:config_detection.bzl%_config_detection",
+            "attributes": {}
+          }
+        },
+        "recordedRepoMappingEntries": []
+      }
+    },
     "@@rules_kotlin+//src/main/starlark/core/repositories:bzlmod_setup.bzl%rules_kotlin_extensions": {
       "general": {
         "bzlTransitiveDigest": "hUTp2w+RUVdL7ma5esCXZJAFnX7vLbVfLd7FwnQI6bU=",

asl/base/annotations.hpp

@@ -6,8 +6,8 @@
 
 #include "asl/base/config.hpp"
 
-#if ASL_COMPILER_CLANG_CL
+#if defined(ASL_COMPILER_CLANG_CL)
     #define ASL_NO_UNIQUE_ADDRESS [[msvc::no_unique_address]]
-#elif ASL_COMPILER_CLANG
+#elif defined(ASL_COMPILER_CLANG)
     #define ASL_NO_UNIQUE_ADDRESS [[no_unique_address]]
 #endif

asl/base/assert.hpp

@@ -18,9 +18,9 @@ void report_assert_failure(const char* msg, const source_location& sl = source_l
 
 } // namespace asl
 
-#if ASL_COMPILER_CLANG_CL
+#if defined(ASL_COMPILER_CLANG_CL)
     #define ASL_DEBUG_BREAK() __debugbreak()
-#elif ASL_COMPILER_CLANG
+#elif defined(ASL_COMPILER_CLANG)
     #define ASL_DEBUG_BREAK() __builtin_debugtrap()
 #endif
 

asl/base/bit_tests.cpp

@@ -15,6 +15,11 @@ ASL_TEST(has_single_bit)
     ASL_TEST_EXPECT(!asl::has_single_bit(0U));
     ASL_TEST_EXPECT(!asl::has_single_bit(3U));
     ASL_TEST_EXPECT(!asl::has_single_bit(341U));
+    int k = 0x7fffffff;
+  k += 1;
+  int *array = new int[100];
+  delete [] array;
+  ASL_TEST_EXPECT(array[1] == 0);  // BOOM
 }
 
 ASL_TEST(popcount) // NOLINT(*-cognitive-complexity)

asl/base/integers.hpp

@@ -9,18 +9,18 @@
 using int8_t  = signed char;
 using int16_t = signed short;
 using int32_t = signed int;
-#if ASL_OS_WINDOWS
+#if defined(ASL_OS_WINDOWS)
     using int64_t = signed long long;
-#elif ASL_OS_LINUX
+#elif defined(ASL_OS_LINUX)
     using int64_t = signed long;
 #endif
 
 using uint8_t  = unsigned char;
 using uint16_t = unsigned short;
 using uint32_t = unsigned int;
-#if ASL_OS_WINDOWS
+#if defined(ASL_OS_WINDOWS)
     using uint64_t = unsigned long long;
-#elif ASL_OS_LINUX
+#elif defined(ASL_OS_LINUX)
     using uint64_t = unsigned long;
 #endif
 

asl/memory/allocator.cpp

@@ -15,11 +15,11 @@
 
 void* asl::GlobalHeap::alloc(const layout& layout)
 {
-#if ASL_OS_WINDOWS
+#if defined(ASL_OS_WINDOWS)
     void* ptr = ::_aligned_malloc(
         static_cast<size_t>(layout.size),
         static_cast<size_t>(layout.align));
-#elif ASL_OS_LINUX
+#elif defined(ASL_OS_LINUX)
     void* ptr = ::aligned_alloc(
         static_cast<size_t>(layout.align),
         static_cast<size_t>(layout.size));
@@ -30,11 +30,11 @@ void* asl::GlobalHeap::alloc(const layout& layout)
 
 void* asl::GlobalHeap::realloc(void* old_ptr, [[maybe_unused]] const layout& old_layout, const layout& new_layout)
 {
-#if ASL_OS_WINDOWS
+#if defined(ASL_OS_WINDOWS)
     return ::_aligned_realloc(old_ptr,
         static_cast<size_t>(new_layout.size),
         static_cast<size_t>(new_layout.align));
-#elif ASL_OS_LINUX
+#elif defined(ASL_OS_LINUX)
     if (new_layout.align <= old_layout.align)
     {
         void* new_ptr = ::realloc(old_ptr, static_cast<size_t>(new_layout.size));
@@ -51,9 +51,9 @@ void* asl::GlobalHeap::realloc(void* old_ptr, [[maybe_unused]] const layout& old
 
 void asl::GlobalHeap::dealloc(void* ptr, const layout&)
 {
-#if ASL_OS_WINDOWS
+#if defined(ASL_OS_WINDOWS)
     ::_aligned_free(ptr);
-#elif ASL_OS_LINUX
+#elif defined(ASL_OS_LINUX)
     ::free(ptr);
 #endif
 }

bazel/clang_toolchain/BUILD.bazel

@@ -0,0 +1,4 @@
+# Copyright 2025 Steven Le Rouzic
+#
+# SPDX-License-Identifier: BSD-3-Clause
+

bazel/clang_toolchain/clang_config.bzl.tpl

@@ -0,0 +1,8 @@
+# Copyright 2025 Steven Le Rouzic
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+CLANG_BINDIR = "{CLANG_BINDIR}"
+CLANG_LIBDIR = "{CLANG_LIBDIR}"
+CLANG_INCLUDE_DIRS = {CLANG_INCLUDE_DIRS}
+

bazel/clang_toolchain/clang_toolchain.BUILD.bazel

@@ -0,0 +1,19 @@
+# Copyright 2025 Steven Le Rouzic
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+load(":toolchain_config.bzl", "declare_toolchain")
+
+filegroup(name = "empty")
+
+PAIRS = [
+    ("windows", "x86_64"),
+    ("linux",   "x86_64"),
+    ("linux",   "aarch64"),
+]
+
+[
+    declare_toolchain(name = "%s_%s_toolchain" % (os, arch), os = os, arch = arch)
+    for (os, arch) in PAIRS
+]
+

bazel/clang_toolchain/config_detection.bzl

@@ -0,0 +1,113 @@
+# Copyright 2025 Steven Le Rouzic
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+def _copy_file(ctx, from_path, to_path):
+    content = ctx.read(from_path)
+    ctx.file(to_path, content = content)
+
+def _get_clang_info(ctx, clang_path, line_prefix):
+    result = ctx.execute([clang_path, "--version"])
+    if result.return_code != 0:
+        return None
+
+    for l in result.stdout.splitlines():
+        if l.startswith(line_prefix):
+            l = l[len(line_prefix):]
+            return l.split(" ")[0]
+
+    return None
+
+def _get_clang_version(ctx, clang_path):
+    return _get_clang_info(ctx, clang_path, "clang version ")
+
+def _get_clang_lib_dir(ctx, clang_path):
+    result = ctx.execute([clang_path, "-no-canonical-prefixes", "--print-resource-dir"])
+    if result.return_code != 0:
+        return None
+
+    return result.stdout
+
+def _get_include_dirs(ctx, clang_path):
+    ctx.file("detect.cpp", content = "")
+    detect_path = ctx.path("detect.cpp")
+    res = ctx.execute([
+        clang_path,
+        "-v",
+        "-no-canonical-prefixes",
+        "-fsyntax-only",
+        "-x", "c++",
+        detect_path,
+    ])
+
+    lines = res.stderr.splitlines()
+    listing_include_dirs = False
+    include_dirs = []
+
+    for l in lines:
+        if l.startswith("#include <...> search starts here:"):
+            listing_include_dirs = True
+        elif l.startswith("End of search list."):
+            listing_include_dirs = False
+        elif listing_include_dirs:
+            include_dirs.append(l.strip())
+
+    return include_dirs
+
+def _impl(ctx):
+    _copy_file(ctx, ctx.attr._build_bazel, "BUILD.bazel")
+    _copy_file(ctx, ctx.attr._toolchain_config_bzl, "toolchain_config.bzl")
+
+    clang_path = ctx.which("clang")
+    if not clang_path:
+        fail("Could not find clang")
+
+    clang_version = _get_clang_version(ctx, clang_path)
+    if not clang_version:
+        fail("Could not detect clang version")
+
+    clang_lib_dir = _get_clang_lib_dir(ctx, clang_path)
+    if not clang_lib_dir:
+        fail("Could not detect clang lib dir")
+
+    include_dirs = _get_include_dirs(ctx, clang_path)
+    if not include_dirs:
+        fail("Could not detect include dirs")
+
+    ctx.template(
+        "clang_config.bzl",
+        ctx.attr._clang_config_bzl_tpl,
+        executable = False,
+        substitutions = {
+            "{CLANG_BINDIR}": str(clang_path.dirname),
+            "{CLANG_LIBDIR}": str(clang_lib_dir).strip().replace("\\", "/"),
+            "{CLANG_INCLUDE_DIRS}": str(include_dirs),
+        },
+    )
+
+
+_config_detection = repository_rule(
+    implementation = _impl,
+    local = True,
+    configure = True,
+    attrs = {
+        "_build_bazel": attr.label(
+            default = Label("//bazel/clang_toolchain:clang_toolchain.BUILD.bazel"),
+            allow_single_file = True,
+        ),
+        "_toolchain_config_bzl": attr.label(
+            default = Label("//bazel/clang_toolchain:toolchain_config.bzl"),
+            allow_single_file = True,
+        ),
+        "_clang_config_bzl_tpl": attr.label(
+            default = Label("//bazel/clang_toolchain:clang_config.bzl.tpl"),
+            allow_single_file = True,
+        ),
+    },
+)
+
+clang_toolchain = module_extension(
+    implementation = lambda ctx: _config_detection(
+        name = "clang_toolchain",
+    ),
+)

bazel/clang_toolchain/toolchain_config.bzl

@@ -0,0 +1,596 @@
+# Copyright 2025 Steven Le Rouzic
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+load(
+    "//:clang_config.bzl",
+    "CLANG_BINDIR",
+    "CLANG_LIBDIR",
+    "CLANG_INCLUDE_DIRS",
+)
+
+load("@rules_cc//cc:action_names.bzl", "ACTION_NAMES")
+
+load(
+    "@rules_cc//cc:cc_toolchain_config_lib.bzl",
+    "action_config",
+    "artifact_name_pattern",
+    "feature",
+    "feature_set",
+    "flag_group",
+    "flag_set",
+    "tool",
+    "tool_path",
+    "variable_with_value",
+)
+
+CPP_COMPILE_ACTIONS = [
+    ACTION_NAMES.cpp_compile,
+    ACTION_NAMES.cpp_header_parsing
+]
+
+C_COMPILE_ACTIONS = [
+    ACTION_NAMES.c_compile,
+]
+
+COMPILE_ACTIONS = C_COMPILE_ACTIONS + CPP_COMPILE_ACTIONS
+
+LINK_ACTIONS = [
+    ACTION_NAMES.cpp_link_dynamic_library,
+    ACTION_NAMES.cpp_link_nodeps_dynamic_library,
+    ACTION_NAMES.cpp_link_executable,
+]
+
+ARCHIVE_ACTIONS = [
+    ACTION_NAMES.cpp_link_static_library,
+]
+
+def _impl(ctx):
+    os = ctx.attr.os
+    is_windows = os == "windows"
+    exe_suffix = ".exe" if is_windows else ""
+
+    tool_paths = [
+        tool_path(name = "ar",      path = CLANG_BINDIR + "/llvm-ar" + exe_suffix),
+        tool_path(name = "ld",      path = CLANG_BINDIR + "/ld.lld" + exe_suffix),
+        tool_path(name = "nm",      path = CLANG_BINDIR + "/llvm-nm" + exe_suffix),
+        tool_path(name = "objdump", path = CLANG_BINDIR + "/llvm-objdump" + exe_suffix),
+        tool_path(name = "strip",   path = CLANG_BINDIR + "/llvm-strip" + exe_suffix),
+        tool_path(name = "gcc",     path = CLANG_BINDIR + "/clang" + exe_suffix),
+        tool_path(name = "cpp",     path = CLANG_BINDIR + "/clang++" + exe_suffix),
+    ]
+
+    action_configs = [
+        action_config(action_name = name, enabled = True, tools = [tool(path = CLANG_BINDIR + "/clang" + exe_suffix)])
+        for name in C_COMPILE_ACTIONS
+    ] + [
+        action_config(action_name = name, enabled = True, tools = [tool(path = CLANG_BINDIR + "/clang++" + exe_suffix)])
+        for name in CPP_COMPILE_ACTIONS
+    ] + [
+        action_config(action_name = name, enabled = True, tools = [tool(path = CLANG_BINDIR + "/clang++" + exe_suffix)])
+        for name in LINK_ACTIONS
+    ] + [
+        action_config(action_name = name, enabled = True, tools = [tool(path = CLANG_BINDIR + "/llvm-ar" + exe_suffix)])
+        for name in ARCHIVE_ACTIONS
+    ] + [
+        action_config(ACTION_NAMES.strip, enabled = True, tools = [tool(path = CLANG_BINDIR + "/llvm-strip" + exe_suffix)]),
+    ]
+
+    artifact_name_patterns = [
+        artifact_name_pattern(
+            category_name = "object_file",
+            prefix = "",
+            extension = ".obj" if is_windows else ".o",
+        ),
+        artifact_name_pattern(
+            category_name = "static_library",
+            prefix = "" if is_windows else "lib",
+            extension = ".lib" if is_windows else ".a",
+        ),
+        artifact_name_pattern(
+            category_name = "dynamic_library",
+            prefix = "" if is_windows else "lib",
+            extension = ".dll" if is_windows else ".so",
+        ),
+        artifact_name_pattern(
+            category_name = "executable",
+            prefix = "",
+            extension = exe_suffix,
+        ),
+    ]
+
+    asan_link_flag_sets = []
+    ubsan_link_flag_sets = []
+
+    if is_windows:
+        asan_link_flag_sets.append(flag_set(
+            actions = LINK_ACTIONS,
+            flag_groups = [
+                flag_group(
+                    flags = [
+                        "-l\"" + CLANG_LIBDIR + "/lib/windows/clang_rt.asan_dynamic-x86_64.lib\"",
+                    ],
+                ),
+            ],
+        ))
+
+        ubsan_link_flag_sets.append(flag_set(
+            actions = LINK_ACTIONS,
+            flag_groups = [
+                flag_group(
+                    flags = [
+                        "-l\"" + CLANG_LIBDIR + "/lib/windows/clang_rt.ubsan_standalone-x86_64.lib\"",
+                    ],
+                ),
+            ],
+        ))
+
+    features = [
+        feature(name = "no_legacy_features"),
+        feature(name = "opt"),
+        feature(name = "fastbuild"),
+        feature(name = "dbg"),
+        feature(
+            name = "default_flags",
+            enabled = True,
+            flag_sets = [
+                flag_set(
+                    actions = COMPILE_ACTIONS + LINK_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = [
+                                "-no-canonical-prefixes",
+                                "-fcolor-diagnostics",
+                            ],
+                        ),
+                    ],
+                ),
+                flag_set(
+                    actions = LINK_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = [
+                                "-fuse-ld=lld",
+                            ],
+                        ),
+                    ],
+                ),
+                flag_set(
+                    actions = COMPILE_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = [
+                                "-Wno-builtin-macro-redefined",
+                                "-D__DATE__=\"redacted\"",
+                                "-D__TIMESTAMP__=\"redacted\"",
+                                "-D__TIME__=\"redacted\"",
+                                "-c",
+                            ],
+                        ),
+                        flag_group(
+                            flags = ["-frandom-seed=%{output_file}"],
+                            expand_if_available = "output_file",
+                        ),
+                        flag_group(
+                            flags = ["-D%{preprocessor_defines}"],
+                            iterate_over = "preprocessor_defines",
+                        ),
+                        flag_group(
+                            flags = ["-I%{include_paths}"],
+                            iterate_over = "include_paths",
+                        ),
+                        flag_group(
+                            flags = ["-iquote", "%{quote_include_paths}"],
+                            iterate_over = "quote_include_paths",
+                        ),
+                        flag_group(
+                            flags = ["-isystem", "%{system_include_paths}"],
+                            iterate_over = "system_include_paths",
+                        ),
+                        flag_group(
+                            flags = ["-MD", "-MF", "%{dependency_file}"],
+                            expand_if_available = "dependency_file",
+                        ),
+                    ],
+                ),
+                flag_set(
+                    actions = ARCHIVE_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = ["rcsD"],
+                        ),
+                        flag_group(
+                            flags = ["%{output_execpath}"],
+                            expand_if_available = "output_execpath",
+                        ),
+                    ],
+                ),
+                flag_set(
+                    actions = LINK_ACTIONS + ARCHIVE_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            iterate_over = "libraries_to_link",
+                            expand_if_available = "libraries_to_link",
+                            flag_groups = [
+                                flag_group(
+                                    flags = ["-Wl,--start-lib"],
+                                    expand_if_equal = variable_with_value(
+                                        name = "libraries_to_link.type",
+                                        value = "object_file_group",
+                                    ),
+                                ),
+                                flag_group(
+                                    iterate_over = "libraries_to_link.object_files",
+                                    expand_if_equal = variable_with_value(
+                                        name = "libraries_to_link.type",
+                                        value = "object_file_group",
+                                    ),
+                                    flag_groups = [
+                                        flag_group(
+                                            flags = ["%{libraries_to_link.object_files}"],
+                                            expand_if_false = "libraries_to_link.is_whole_archive",
+                                        ),
+                                        flag_group(
+                                            flags = ["-Wl,-force_load,%{libraries_to_link.object_files}"],
+                                            expand_if_true = "libraries_to_link.is_whole_archive",
+                                        ),
+                                    ],
+                                ),
+                                flag_group(
+                                    expand_if_equal = variable_with_value(
+                                        name = "libraries_to_link.type",
+                                        value = "object_file",
+                                    ),
+                                    flag_groups = [
+                                        flag_group(
+                                            flags = ["%{libraries_to_link.name}"],
+                                            expand_if_false = "libraries_to_link.is_whole_archive",
+                                        ),
+                                        flag_group(
+                                            flags = ["-Wl,-force_load,%{libraries_to_link.name}"],
+                                            expand_if_true = "libraries_to_link.is_whole_archive",
+                                        ),
+                                    ],
+                                ),
+                                flag_group(
+                                    expand_if_equal = variable_with_value(
+                                        name = "libraries_to_link.type",
+                                        value = "interface_library",
+                                    ),
+                                    flag_groups = [
+                                        flag_group(
+                                            flags = ["%{libraries_to_link.name}"],
+                                            expand_if_false = "libraries_to_link.is_whole_archive",
+                                        ),
+                                        flag_group(
+                                            flags = ["-Wl,-force_load,%{libraries_to_link.name}"],
+                                            expand_if_true = "libraries_to_link.is_whole_archive",
+                                        ),
+                                    ],
+                                ),
+                                flag_group(
+                                    expand_if_equal = variable_with_value(
+                                        name = "libraries_to_link.type",
+                                        value = "static_library",
+                                    ),
+                                    flag_groups = [
+                                        flag_group(
+                                            flags = ["%{libraries_to_link.name}"],
+                                            expand_if_false = "libraries_to_link.is_whole_archive",
+                                        ),
+                                        flag_group(
+                                            flags = ["-Wl,-force_load,%{libraries_to_link.name}"],
+                                            expand_if_true = "libraries_to_link.is_whole_archive",
+                                        ),
+                                    ],
+                                ),
+                                flag_group(
+                                    flags = ["-l%{libraries_to_link.name}"],
+                                    expand_if_equal = variable_with_value(
+                                        name = "libraries_to_link.type",
+                                        value = "dynamic_library",
+                                    ),
+                                ),
+                                flag_group(
+                                    flags = ["-l:%{libraries_to_link.name}"],
+                                    expand_if_equal = variable_with_value(
+                                        name = "libraries_to_link.type",
+                                        value = "versioned_dynamic_library",
+                                    ),
+                                ),
+                                flag_group(
+                                    expand_if_true = "libraries_to_link.is_whole_archive",
+                                    flag_groups = [
+                                        flag_group(
+                                            expand_if_false = "macos_flags",
+                                            flags = ["-Wl,-no-whole-archive"],
+                                        ),
+                                    ],
+                                ),
+                                flag_group(
+                                    flags = ["-Wl,--end-lib"],
+                                    expand_if_equal = variable_with_value(
+                                        name = "libraries_to_link.type",
+                                        value = "object_file_group",
+                                    ),
+                                ),
+                            ],
+                        ),
+                    ],
+                ),
+            ],
+        ),
+        feature(
+            name = "windows_linker_flags",
+            enabled = is_windows,
+            flag_sets = [
+                flag_set(
+                    actions = LINK_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = [
+                                "-Xlinker",
+                                "/subsystem:console",
+                            ],
+                        ),
+                    ],
+                ),
+            ],
+        ),
+        feature(
+            name = "dbg_flags",
+            enabled = True,
+            requires = [feature_set(["dbg"])],
+            flag_sets = [
+                flag_set(
+                    actions = COMPILE_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = [
+                                "-DDEBUG=1",
+                            ],
+                        ),
+                    ],
+                ),
+                flag_set(
+                    actions = COMPILE_ACTIONS + LINK_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = [
+                                "-g3",
+                            ],
+                        ),
+                    ],
+                ),
+            ],
+        ),
+        feature(
+            name = "fastbuild_flags",
+            enabled = True,
+            requires = [feature_set(["fastbuild"])],
+            flag_sets = [
+                flag_set(
+                    actions = COMPILE_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = [
+                                "-O1",
+                                "-DDEBUG=1",
+                            ],
+                        ),
+                    ],
+                ),
+                flag_set(
+                    actions = COMPILE_ACTIONS + LINK_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = [
+                                "-g1",
+                            ],
+                        ),
+                    ],
+                ),
+            ],
+        ),
+        feature(
+            name = "opt_flags",
+            enabled = True,
+            requires = [feature_set(["opt"])],
+            flag_sets = [
+                flag_set(
+                    actions = COMPILE_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = [
+                                "-O3",
+                                "-DNDEBUG=1",
+                            ],
+                        ),
+                    ],
+                ),
+            ],
+        ),
+        feature(
+            name = "c++20",
+            provides = ["c++_version"],
+            flag_sets = [
+                flag_set(
+                    actions = COMPILE_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = ["-std=c++20"],
+                        ),
+                    ],
+                ),
+            ],
+        ),
+        feature(
+            name = "c++23",
+            provides = ["c++_version"],
+            flag_sets = [
+                flag_set(
+                    actions = COMPILE_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = ["-std=c++23"],
+                        ),
+                    ],
+                ),
+            ],
+        ),
+        feature(
+            name = "asan",
+            implies = ["sanitize"],
+            flag_sets = [
+                flag_set(
+                    actions = COMPILE_ACTIONS + LINK_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = [
+                                "-fsanitize=address",
+                            ],
+                        ),
+                    ],
+                ),
+            ] + asan_link_flag_sets,
+        ),
+        feature(
+            name = "ubsan",
+            implies = ["sanitize"],
+            flag_sets = [
+                flag_set(
+                    actions = COMPILE_ACTIONS + LINK_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = [
+                                "-fsanitize=undefined",
+                            ],
+                        ),
+                    ],
+                ),
+            ] + ubsan_link_flag_sets,
+        ),
+        feature(
+            name = "sanitize",
+            flag_sets = [
+                flag_set(
+                    actions = COMPILE_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = [
+                                "-fno-omit-frame-pointer",
+                                "-fno-sanitize-ignorelist",
+                                "-fno-sanitize-recover=all",
+                            ],
+                        ),
+                    ],
+                ),
+            ],
+        ),
+        feature(
+            name = "final_flags",
+            enabled = True,
+            flag_sets = [
+                flag_set(
+                    actions = COMPILE_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = ["%{user_compile_flags}"],
+                            expand_if_available = "user_compile_flags",
+                            iterate_over = "user_compile_flags",
+                        ),
+                        flag_group(
+                            flags = ["-o", "%{output_file}"],
+                            expand_if_available = "output_file",
+                        ),
+                        flag_group(
+                            flags = ["%{source_file}"],
+                            expand_if_available = "source_file",
+                        ),
+                    ],
+                ),
+                flag_set(
+                    actions = LINK_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = ["%{user_link_flags}"],
+                            expand_if_available = "user_link_flags",
+                            iterate_over = "user_link_flags",
+                        ),
+                        flag_group(
+                            flags = ["-o", "%{output_execpath}"],
+                            expand_if_available = "output_execpath",
+                        ),
+                    ],
+                ),
+                flag_set(
+                    actions = LINK_ACTIONS + ARCHIVE_ACTIONS,
+                    flag_groups = [
+                        flag_group(
+                            flags = ["@%{linker_param_file}"],
+                            expand_if_available = "linker_param_file",
+                        ),
+                    ],
+                ),
+            ],
+        ),
+    ]
+
+    return cc_common.create_cc_toolchain_config_info(
+        ctx = ctx,
+        toolchain_identifier = "%s-toolchain" % os,
+        compiler = "clang",
+        artifact_name_patterns = artifact_name_patterns,
+        cxx_builtin_include_directories = CLANG_INCLUDE_DIRS,
+        tool_paths = tool_paths,
+        action_configs = action_configs,
+        features = features,
+    )
+
+toolchain_config = rule(
+    implementation = _impl,
+    attrs = {
+        "os": attr.string(mandatory = True),
+    },
+    provides = [CcToolchainConfigInfo],
+)
+
+def _declare_toolchain_impl(name, os, arch, visibility):
+    toolchain_config(
+        name = name + "_config",
+        os = os,
+    )
+
+    native.cc_toolchain(
+        name = name + "_cc",
+        toolchain_config = name + "_config",
+        all_files = ":empty",
+        compiler_files = ":empty",
+        linker_files = ":empty",
+        objcopy_files = ":empty",
+        strip_files = ":empty",
+        dwp_files = ":empty",
+    )
+
+    native.toolchain(
+        name = name + "_def",
+        toolchain = name + "_cc",
+        toolchain_type = "@rules_cc//cc:toolchain_type",
+        exec_compatible_with = [
+            "@platforms//cpu:%s" % arch,
+            "@platforms//os:%s" % os,
+        ],
+        target_compatible_with = [
+            "@platforms//cpu:%s" % arch,
+            "@platforms//os:%s" % os,
+        ],
+        visibility = ["//visibility:public"],
+    )
+
+declare_toolchain = macro(
+    implementation = _declare_toolchain_impl,
+    attrs = {
+        "os":   attr.string(mandatory = True, configurable = False),
+        "arch": attr.string(mandatory = True, configurable = False),
+    }
+)

refresh_clangd.sh

@@ -1 +1 @@
-bazel run //tools:refresh_clangd --config=linux -- --config=linux
+bazel run //tools:refresh_clangd

todo.txt

@@ -1 +1,6 @@
-C++26: constexpr cast from void* https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p2738r1.pdf
+constexpr cast from void* +cpp26 https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p2738r1.pdf
+
+add sanitizers features +bazel_clang_toolchain
+linux x64 support +bazel_clang_toolchain
+linux arm64 support +bazel_clang_toolchain
+

tools/fix_line_endings.py

@@ -19,6 +19,7 @@ TO_FIX = [
     "**/*.cpp",
     "**/*.py",
     "**/*.bzl",
+    "**/*.bzl.tpl",
     "**/*.bazel",
     "**/*.txt",
     "**/*.bat",