Avoid unnecessary allocations

1. Reserve `store.late_passes` with 320 and `store.early_passes` with 64, this leaves us some leeway for adding new passes.
2. Add [env] with some MALLOC_CONF for mainly for faster testing, but to also optimize in profiling.

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Author: blyxyas

.cargo/config.toml

@@ -30,3 +30,7 @@ rustflags = ["--remap-path-prefix", "=lintcheck"]
 # without increasing total build times.
 [profile.dev.package.quine-mc_cluskey]
 opt-level = 3
+
+# Configure malloc for faster compiling Clippy itself
+[env]
+MALLOC_CONF = "percpu_arena:phycpu,metadata_thp:always,dirty_decay_ms:300,muzzy_decay_ms:300"

clippy_lints/src/lib.rs

@@ -441,6 +441,10 @@ pub fn explain(name: &str) -> i32 {
 /// Used in `./src/driver.rs`.
 #[expect(clippy::too_many_lines)]
 pub fn register_lint_passes(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
+    // Avoid unnecessary reallocations
+    store.late_passes.reserve(320);
+    store.early_passes.reserve(64);
+
     for (old_name, new_name) in deprecated_lints::RENAMED {
         store.register_renamed(old_name, new_name);
     }