feat: add rust bindings

.github/workflows/main.yml

@@ -114,7 +114,7 @@ jobs:
         path: "~/.cache/bazel"
         key: bazel
     - run: bazel build -c opt //:snmalloc
-    - run: bazel build -c opt //:snmalloc-rs
+    - run: bazel build -c opt //:snmalloc-rust-support
 
   # If this looks remarkably familiar, that's because it is.  Sigh.
   macos:
@@ -166,7 +166,7 @@ jobs:
         path: "~/.cache/bazel"
         key: bazel
     - run: bazel build -c opt //:snmalloc
-    - run: bazel build -c opt //:snmalloc-rs
+    - run: bazel build -c opt //:snmalloc-rust-support
 
 
   # GitHub doesn't natively support *BSD, but we can run them in VMs on Mac /

BUILD.bazel

@@ -1,4 +1,7 @@
+load("@bazel_skylib//rules:native_binary.bzl", "native_binary")
 load("@rules_foreign_cc//foreign_cc:defs.bzl", "cmake")
+load("@rules_cc//cc:defs.bzl", "cc_import")
+load("@rules_rust_bindgen//:defs.bzl", "rust_bindgen_toolchain")
 
 filegroup(
     name = "srcs",
@@ -38,7 +41,6 @@ CMAKE_FLAGS = {
     "SNMALLOC_OPTIMISE_FOR_CURRENT_MACHINE": "ON",
     "SNMALLOC_USE_SELF_VENDORED_STL": "OFF",
     "SNMALLOC_IPO": "ON",
-    "USE_SNMALLOC_STATS": "ON",
 } | select({
     ":release_with_debug": {"CMAKE_BUILD_TYPE": "RelWithDebInfo"},
     ":release": {"CMAKE_BUILD_TYPE": "Release"},
@@ -65,10 +67,11 @@ cmake(
     ],
     postfix_script = "ninja",
     visibility = ["//visibility:public"],
+    alwayslink = True,
 )
 
 cmake(
-    name = "snmalloc-rs",
+    name = "snmalloc-rust-support",
     cache_entries = CMAKE_FLAGS | {
         "SNMALLOC_RUST_SUPPORT": "ON",
     },
@@ -87,5 +90,39 @@ cmake(
         "libsnmalloc-new-override.a",
     ],
     postfix_script = "ninja",
+    visibility = ["//src/snmalloc_rs:__pkg__"],
+    alwayslink = True,
+)
+
+alias(
+    name = "snmalloc_rs",
+    actual = "//src/snmalloc_rs",
     visibility = ["//visibility:public"],
 )
+
+native_binary(
+    name = "clang",
+    src = "@llvm_toolchain_llvm//:bin/clang",
+    visibility = ["//snmalloc_rs:__subpackages__"],
+)
+
+cc_import(
+    name = "libclang",
+    shared_library = "@llvm_toolchain_llvm//:libclang",
+    visibility = ["//snmalloc_rs:__subpackages__"],
+)
+
+rust_bindgen_toolchain(
+    name = "rust_bindgen_toolchain",
+    bindgen = "@rules_rust_bindgen//3rdparty:bindgen",
+    clang = ":clang",
+    libclang = ":libclang",
+    visibility = ["//snmalloc_rs:__subpackages__"],
+)
+
+toolchain(
+    name = "default_bindgen_toolchain",
+    toolchain = ":rust_bindgen_toolchain",
+    toolchain_type = "@rules_rust_bindgen//:toolchain_type",
+    visibility = ["//snmalloc_rs:__subpackages__"],
+)

MODULE.bazel

@@ -1,6 +1,43 @@
 module(name = "snmalloc")
 
+bazel_dep(name = "bazel_skylib", version = "1.7.1")
 bazel_dep(name = "rules_cc", version = "0.1.1")
 bazel_dep(name = "rules_foreign_cc", version = "0.14.0")
 bazel_dep(name = "fuzztest", version = "20250214.0")
 bazel_dep(name = "googletest", version = "1.16.0")
+bazel_dep(name = "toolchains_llvm", version = "1.4.0")
+bazel_dep(name = "rules_rust", version = "0.61.0")
+bazel_dep(name = "rules_rust_bindgen", version = "0.61.0")
+
+# Configure and register the toolchain.
+# https://github.com/bazel-contrib/toolchains_llvm/blob/master/toolchain/internal/llvm_distributions.bzl
+llvm = use_extension("@toolchains_llvm//toolchain/extensions:llvm.bzl", "llvm", dev_dependency = True)
+
+# LLVM toolchain.
+llvm.toolchain(
+    name = "llvm_toolchain",
+    cxx_standard = {"": "c++20"},
+    llvm_version = "17.0.6",
+)
+use_repo(llvm, "llvm_toolchain", "llvm_toolchain_llvm")
+
+#register_toolchains("@llvm_toolchain//:all")
+
+rust = use_extension("@rules_rust//rust:extensions.bzl", "rust", dev_dependency = True)
+rust.toolchain(
+    edition = "2021",
+    versions = [
+        "1.86.0",
+    ],
+)
+use_repo(rust, "rust_toolchains")
+
+register_toolchains(
+    "@rust_toolchains//:all",
+    dev_dependency = True,
+)
+
+register_toolchains(
+    "//:default_bindgen_toolchain",
+    dev_dependency = True,
+)

README.md

@@ -3,7 +3,7 @@
 snmalloc is a high-performance allocator. 
 snmalloc can be used directly in a project as a header-only C++ library, 
 it can be `LD_PRELOAD`ed on Elf platforms (e.g. Linux, BSD),
-and there is a [crate](https://crates.io/crates/snmalloc-rs) to use it from Rust.
+and there is a [crate](https://crates.io/crates/snmalloc_rs) to use it from Rust.
 
 Its key design features are:
 

fuzzing/BUILD.bazel

@@ -9,7 +9,7 @@ cc_test(
     copts = [
         "-fsanitize=address",
     ] + select({
-        "@bazel_tools//tools/cpp:clang-cl": ["-fexperimental-library"],  # needed for std::execution::unseq,
+        "@bazel_tools//src/conditions:darwin": ["-fexperimental-library"],
         "//conditions:default": ["-mcx16"],
     }),
     defines = [

src/snmalloc_rs/BUILD.bazel

@@ -0,0 +1,65 @@
+load("@bazel_skylib//rules:common_settings.bzl", "string_flag")
+load("@rules_rust//rust:defs.bzl", "rust_binary", "rust_library", "rust_test")
+load("@rules_rust_bindgen//:defs.bzl", "rust_bindgen_library")
+load("@rules_cc//cc:defs.bzl", "cc_library")
+
+cc_library(
+    name = "wrapper",
+    hdrs = ["wrapper.h"],
+    defines = ["SNMALLOC_USE_WAIT_ON_ADDRESS"],
+    linkstatic = True,
+    visibility = ["//visibility:private"],
+    deps = ["//:snmalloc-rust-support"],
+)
+
+rust_bindgen_library(
+    name = "snmalloc_sys",
+    bindgen_flags = [
+        "--allowlist-function=aligned_alloc",
+        "--allowlist-function=calloc",
+        "--allowlist-function=get_malloc_info_v1",  # getting mangles
+        "--allowlist-function=malloc",
+        "--allowlist-function=malloc_usable_size",  # getting mangles
+        "--allowlist-function=realloc",
+        "--allowlist-function=free",
+        # comment out the above and uncomment the two lines below to generate bindings for everything
+        # "--opaque-type=std::.*",
+        # "--blocklist-item=std::value",
+        "--use-core",  # don't compile with std, allows baremetal envs
+    ],
+    cc_lib = ":wrapper",
+    clang_flags = [
+        # "-v",  # enable for debugging
+        "-x",
+        "c++",
+        "-std=c++20",
+        "-I",
+    ],
+    header = ":wrapper.h",
+)
+
+rust_library(
+    name = "snmalloc_rs",
+    srcs = ["lib.rs"],
+    visibility = ["//visibility:public"],
+    deps = [":snmalloc_sys"],
+)
+
+# bazel test //src/snmalloc_rs/... --extra_toolchains=@llvm_toolchain//:cc-toolchain-x86_64-linux
+rust_test(
+    name = "test",
+    size = "small",
+    crate = ":snmalloc_rs",
+)
+
+# bazel run //snmalloc_rs:main --extra_toolchains=@llvm_toolchain//:cc-toolchain-x86_64-linux
+rust_binary(
+    name = "main",
+    srcs = ["main.rs"],
+    rustc_flags = [
+        "-Ccodegen-units=1",
+        "-Copt-level=3",
+        "-Cstrip=symbols",
+    ],
+    deps = [":snmalloc_rs"],
+)

src/snmalloc_rs/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "snmalloc_rs"
+version = "0.0.0"
+edition = "2024"
+publish = false
+homepage = "https://github.com/microsoft/snmalloc"
+repository = "https://github.com/microsoft/snmalloc"
+
+
+[lib]
+path = "lib.rs"
+
+[dependencies]
+libc = "0.2.172"