Draft: Add custom allocator support (mimalloc)

mozjs-sys/Cargo.toml

@@ -16,6 +16,8 @@ name = "mozjs_sys"
 doctest = false
 
 [features]
+default = ["mimalloc"] # Testingl only - remove me
+mimalloc = [ "dep:mimalloc"]
 debugmozjs = []
 profilemozjs = []
 jitspew = []
@@ -26,6 +28,7 @@ crown = []
 oom_with_hook = []
 
 [dependencies]
+mimalloc = { version = "0.1.48", optional = true}
 libc.workspace = true
 encoding_c = "0.9.8"
 encoding_c_mem = "0.2.6"

mozjs-sys/build.rs

@@ -138,6 +138,7 @@ fn main() {
 
 fn build_spidermonkey(build_dir: &Path) {
     let target = env::var("TARGET").unwrap();
+    let cargo_manifest_dir = PathBuf::from(env::var_os("CARGO_MANIFEST_DIR").unwrap());
     let make;
 
     #[cfg(windows)]
@@ -210,24 +211,37 @@ fn build_spidermonkey(build_dir: &Path) {
     }
 
     cppflags.push(get_cc_rs_env_os("CPPFLAGS").unwrap_or_default());
-    cmd.env("CPPFLAGS", cppflags);
 
     if let Some(makeflags) = env::var_os("CARGO_MAKEFLAGS") {
         cmd.env("MAKEFLAGS", makeflags);
     }
 
     let mut cxxflags = vec![];
 
+    if env::var_os("CARGO_FEATURE_MIMALLOC").is_some() {
+        let mut flags = vec![];
+        // let include_dir = env::var("DEP_DFMALLOC_INCLUDE_DIR").expect("Required variable not set with feature dfmalloc");
+        // flags.push(format!("-I{}", &include_dir.replace("\\", "/")));
+        let header_dir = cargo_manifest_dir.join("src/custom_alloc").to_str().expect("utf-8").to_string();
+        flags.push(format!("-I{}", header_dir));
+        println!("cargo:rerun-if-changed={}", header_dir);
+
+       //  flags.push("-DJS_USE_CUSTOM_ALLOCATOR".to_string());
+        cppflags.extend(flags.iter().map(|s| OsString::from(s)));
+        cxxflags.extend(flags);
+    }
+
     if target.contains("apple") || target.contains("freebsd") || target.contains("ohos") {
         cxxflags.push(String::from("-stdlib=libc++"));
     }
 
+    cmd.env("CPPFLAGS", cppflags);
+
     let base_cxxflags = env::var("CXXFLAGS").unwrap_or_default();
     let mut cxxflags = cxxflags.join(" ");
     cxxflags.push_str(&base_cxxflags);
     cmd.env("CXXFLAGS", cxxflags);
 
-    let cargo_manifest_dir = PathBuf::from(env::var_os("CARGO_MANIFEST_DIR").unwrap());
     let result = cmd
         .args(&["-R", "-f"])
         .arg(cargo_manifest_dir.join("makefile.cargo"))
@@ -292,6 +306,11 @@ fn build(build_dir: &Path, target: BuildTarget) {
 
     build.flag(include_file_flag(build.get_compiler().is_like_msvc()));
     build.flag(&js_config_path(build_dir));
+    let cargo_manifest_dir = PathBuf::from(env::var_os("CARGO_MANIFEST_DIR").unwrap());
+
+    let header_dir = cargo_manifest_dir.join("src/custom_alloc").to_str().expect("utf-8").to_string();
+    build.include(&header_dir);
+    println!("cargo:rerun-if-changed={}", header_dir);
 
     for path in target.include_paths(build_dir) {
         build.include(path);
@@ -313,6 +332,10 @@ fn build_bindings(build_dir: &Path, target: BuildTarget) {
     config &= !CodegenConfig::DESTRUCTORS;
     config &= !CodegenConfig::METHODS;
 
+    let cargo_manifest_dir = PathBuf::from(env::var_os("CARGO_MANIFEST_DIR").unwrap());
+
+    let header_dir = cargo_manifest_dir.join("src/custom_alloc").to_str().expect("utf-8").to_string();
+
     let mut builder = bindgen::builder()
         .rust_target(minimum_rust_target())
         .header(target.path())
@@ -324,6 +347,7 @@ fn build_bindings(build_dir: &Path, target: BuildTarget) {
         .size_t_is_usize(true)
         .enable_cxx_namespaces()
         .with_codegen_config(config)
+        .clang_arg(format!("-I{}", header_dir))
         .clang_args(cc_flags(true));
 
     if env::var("TARGET").unwrap().contains("wasi") {
@@ -432,6 +456,8 @@ fn link_static_lib_binaries(build_dir: &Path) {
         // needing to use the WASI-SDK's clang for linking, which is annoying.
         println!("cargo:rustc-link-lib=stdc++")
     }
+    // FIXME: guard me, or remove me or whatever.
+    // println!("cargo:rustc-link-lib=mimalloc");
 
     if target.contains("wasi") {
         println!("cargo:rustc-link-lib=wasi-emulated-getpid");
@@ -463,6 +489,9 @@ fn should_build_from_source() -> bool {
     } else if env::var_os("CARGO_FEATURE_INTL").is_none() {
         println!("intl feature is disabled. Building from source directly.");
         true
+    } else if env::var_os("CARGO_FEATURE_MIMALLOC").is_some() {
+        println!("mimalloc feature is enabled. Building from source directly.");
+        true
     } else {
         false
     }