chore: add dhat feature (#26285)

Cargo.lock

@@ -1188,6 +1188,7 @@ dependencies = [
  "deno_task_shell",
  "deno_terminal 0.2.0",
  "deno_tower_lsp",
+ "dhat",
  "dissimilar",
  "dotenvy",
  "dprint-plugin-json",
@@ -2425,6 +2426,22 @@ version = "1.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b6e854126756c496b8c81dec88f9a706b15b875c5849d4097a3854476b9fdf94"
 
+[[package]]
+name = "dhat"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "98cd11d84628e233de0ce467de10b8633f4ddaecafadefc86e13b84b8739b827"
+dependencies = [
+ "backtrace",
+ "lazy_static",
+ "mintex",
+ "parking_lot",
+ "rustc-hash 1.1.0",
+ "serde",
+ "serde_json",
+ "thousands",
+]
+
 [[package]]
 name = "diff"
 version = "0.1.13"
@@ -4435,6 +4452,12 @@ dependencies = [
  "simd-adler32",
 ]
 
+[[package]]
+name = "mintex"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9bec4598fddb13cc7b528819e697852653252b760f1228b7642679bf2ff2cd07"
+
 [[package]]
 name = "mio"
 version = "0.8.11"
@@ -7181,6 +7204,12 @@ dependencies = [
  "syn 2.0.72",
 ]
 
+[[package]]
+name = "thousands"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3bf63baf9f5039dadc247375c29eb13706706cfde997d0330d05aa63a77d8820"
+
 [[package]]
 name = "thread_local"
 version = "1.1.8"

cli/Cargo.toml

@@ -38,6 +38,11 @@ path = "./bench/lsp_bench_standalone.rs"
 
 [features]
 default = ["upgrade", "__vendored_zlib_ng"]
+# A feature that enables heap profiling with dhat on Linux.
+# 1. Compile with `cargo build --profile=release-with-debug --features=dhat-heap`
+# 2. Run the executable. It will output a dhat-heap.json file.
+# 3. Open the json file in https://nnethercote.github.io/dh_view/dh_view.html
+dhat-heap = ["dhat"]
 # A feature that enables the upgrade subcommand and the background check for
 # available updates (of deno binary). This is typically disabled for (Linux)
 # distribution packages.
@@ -98,6 +103,7 @@ color-print.workspace = true
 console_static_text.workspace = true
 dashmap.workspace = true
 data-encoding.workspace = true
+dhat = { version = "0.3.3", optional = true }
 dissimilar = "=1.0.4"
 dotenvy = "0.15.7"
 dprint-plugin-json = "=0.19.3"

cli/main.rs

@@ -61,6 +61,10 @@ use std::ops::Deref;
 use std::path::PathBuf;
 use std::sync::Arc;
 
+#[cfg(feature = "dhat-heap")]
+#[global_allocator]
+static ALLOC: dhat::Alloc = dhat::Alloc;
+
 /// Ensures that all subcommands return an i32 exit code and an [`AnyError`] error type.
 trait SubcommandOutput {
   fn output(self) -> Result<i32, AnyError>;
@@ -387,6 +391,9 @@ pub(crate) fn unstable_exit_cb(feature: &str, api_name: &str) {
 }
 
 pub fn main() {
+  #[cfg(feature = "dhat-heap")]
+  let profiler = dhat::Profiler::new_heap();
+
   setup_panic_hook();
 
   util::unix::raise_fd_limit();
@@ -407,7 +414,12 @@ pub fn main() {
     run_subcommand(Arc::new(flags)).await
   };
 
-  match create_and_run_current_thread_with_maybe_metrics(future) {
+  let result = create_and_run_current_thread_with_maybe_metrics(future);
+
+  #[cfg(feature = "dhat-heap")]
+  drop(profiler);
+
+  match result {
     Ok(exit_code) => std::process::exit(exit_code),
     Err(err) => exit_for_error(err),
   }