[bazel] Use zstd from the BCR (#169146)

This way if the downstream consuming project uses zstd we make sure
they are dedup'd. This uses a new rule to make sure layering_check still
works while allowing us to augment the upstream library rules with LLVM
specific `defines`.

Author: keith

utils/bazel/MODULE.bazel

@@ -15,14 +15,14 @@ bazel_dep(name = "rules_cc", version = "0.2.11")
 bazel_dep(name = "rules_foreign_cc", version = "0.15.1")
 bazel_dep(name = "rules_python", version = "1.6.3")
 bazel_dep(name = "rules_shell", version = "0.6.1")
+bazel_dep(name = "zstd", version = "1.5.7", repo_name = "llvm_zstd")
 
 llvm_repos_extension = use_extension(":extensions.bzl", "llvm_repos_extension")
 use_repo(
     llvm_repos_extension,
     "gmp",
     "llvm-raw",
     "llvm_zlib",
-    "llvm_zstd",
     "mpc",
     "mpfr",
     "nanobind",

utils/bazel/MODULE.bazel.lock

@@ -79,16 +79,6 @@ def _llvm_repos_extension_impl(module_ctx):
         build_file = "@llvm-raw//utils/bazel/third_party_build:pfm.BUILD",
     )
 
-    http_archive(
-        name = "llvm_zstd",
-        build_file = "@llvm-raw//utils/bazel/third_party_build:zstd.BUILD",
-        sha256 = "7c42d56fac126929a6a85dbc73ff1db2411d04f104fae9bdea51305663a83fd0",
-        strip_prefix = "zstd-1.5.2",
-        urls = [
-            "https://github.com/facebook/zstd/releases/download/v1.5.2/zstd-1.5.2.tar.gz",
-        ],
-    )
-
     http_archive(
         name = "pybind11",
         url = "https://github.com/pybind/pybind11/archive/v2.10.3.zip",

utils/bazel/extensions.bzl

@@ -105,8 +105,8 @@ cc_library(
         "//llvm:TargetParser",
         "//llvm:TransformUtils",
         "//llvm:config",
+        "//third-party:zstd",
         "@llvm_zlib//:zlib",
-        "@llvm_zstd//:zstd",
     ],
 )
 

utils/bazel/llvm-project-overlay/lld/BUILD.bazel

@@ -331,7 +331,7 @@ cc_library(
         # We unconditionally depend on the custom LLVM zstd wrapper. This will
         # be an empty library unless zstd is enabled, in which case it will
         # both provide the necessary dependencies and configuration defines.
-        "@llvm_zstd//:zstd",
+        "//third-party:zstd",
     ],
 )
 

utils/bazel/llvm-project-overlay/llvm/BUILD.bazel

@@ -0,0 +1,34 @@
+# This file is licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
+load(":cc_library_wrapper.bzl", "cc_library_wrapper")
+
+package(default_visibility = ["//visibility:public"])
+
+bool_flag(
+    name = "llvm_enable_zstd",
+    build_setting_default = True,
+)
+
+config_setting(
+    name = "llvm_zstd_enabled",
+    flag_values = {":llvm_enable_zstd": "true"},
+)
+
+cc_library_wrapper(
+    name = "zstd",
+    defines = select({
+        ":llvm_zstd_enabled": [
+            "LLVM_ENABLE_ZSTD=1",
+            "ZSTD_MULTITHREAD",
+        ],
+        "//conditions:default": [],
+    }),
+    deps = select({
+        ":llvm_zstd_enabled": [
+            "@llvm_zstd//:zstd",
+        ],
+        "//conditions:default": [],
+    }),
+)

utils/bazel/llvm-project-overlay/third-party/BUILD.bazel

@@ -0,0 +1,50 @@
+# This file is licensed under the Apache License v2.0 with LLVM Exceptions.
+# See https://llvm.org/LICENSE.txt for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+"""Re-export a cc_library with added LLVM specific settings.
+
+This re-exports the dependent libraries in a way that satisfies layering_check
+
+cc_library_wrapper(
+    name = "library_wrapper",
+    deps = [
+        "@example//:library",
+    ],
+    defines = [
+        "LLVM_ENABLE_EXAMPLE=1",
+    ],
+)
+"""
+
+load("@rules_cc//cc/common:cc_common.bzl", "cc_common")
+load("@rules_cc//cc/common:cc_info.bzl", "CcInfo")
+
+visibility("private")
+
+def _cc_library_wrapper_impl(ctx):
+    all_cc_infos = [dep[CcInfo] for dep in ctx.attr.deps]
+    if ctx.attr.defines:
+        all_cc_infos.append(CcInfo(
+            compilation_context = cc_common.create_compilation_context(
+                defines = depset(ctx.attr.defines),
+            ),
+        ))
+
+    return cc_common.merge_cc_infos(direct_cc_infos = all_cc_infos)
+
+cc_library_wrapper = rule(
+    implementation = _cc_library_wrapper_impl,
+    attrs = {
+        "deps": attr.label_list(
+            doc = "Dependencies to cc_library targets to re-export.",
+            providers = [CcInfo],
+        ),
+        "defines": attr.string_list(
+            doc = "Additional preprocessor definitions to add to all dependent targets.",
+            default = [],
+        ),
+    },
+    doc = "Re-export a cc_library with added LLVM specific settings.",
+    provides = [CcInfo],
+)

utils/bazel/llvm-project-overlay/third-party/cc_library_wrapper.bzl

@@ -1,28 +1,18 @@
 # This file is licensed under the Apache License v2.0 with LLVM Exceptions.
 # See https://llvm.org/LICENSE.txt for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
+load("@rules_cc//cc:cc_library.bzl", "cc_library")
 
 package(
     default_visibility = ["//visibility:public"],
     # BSD/MIT-like license (for zstd)
     licenses = ["notice"],
 )
 
-bool_flag(
-    name = "llvm_enable_zstd",
-    build_setting_default = True,
-)
-
-config_setting(
-    name = "llvm_zstd_enabled",
-    flag_values = {":llvm_enable_zstd": "true"},
-)
-
 cc_library(
     name = "zstd",
     srcs = select({
-        ":llvm_zstd_enabled": glob([
+        "@llvm-project//third-party:llvm_zstd_enabled": glob([
             "lib/common/*.c",
             "lib/common/*.h",
             "lib/compress/*.c",
@@ -36,15 +26,15 @@ cc_library(
         "//conditions:default": [],
     }),
     hdrs = select({
-        ":llvm_zstd_enabled": [
+        "@llvm-project//third-party:llvm_zstd_enabled": [
             "lib/zdict.h",
             "lib/zstd.h",
             "lib/zstd_errors.h",
         ],
         "//conditions:default": [],
     }),
     defines = select({
-        ":llvm_zstd_enabled": [
+        "@llvm-project//third-party:llvm_zstd_enabled": [
             "LLVM_ENABLE_ZSTD=1",
             "ZSTD_MULTITHREAD",
         ],