feat(tvix/eval): Forbid Hash{Map,Set}, use Fx instead r/8453

Per https://nnethercote.github.io/perf-book/hashing.html, we have
basically no reason to use the default hasher over a faster,
non-DoS-resistant hasher. This gives a nice perf boost basically for
free:

hello outpath           time:   [704.76 ms 714.91 ms 725.63 ms]
                        change: [-7.2391% -6.1018% -4.9189%] (p = 0.00 < 0.05)
                        Performance has improved.

Change-Id: If5587f444ed3af69f8af4eead6af3ea303b4ae68
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12046
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
Reviewed-by: Ilan Joselevich <personal@ilanjoselevich.com>
Autosubmit: aspen <root@gws.fyi>

3 files changed, 10 insertions, 6 deletions

diff --git a/tvix/cli/Cargo.toml b/tvix/cli/Cargo.toml
index abbb7e6c2bd0..7f93da85d47a 100644
--- a/tvix/cli/Cargo.toml
+++ b/tvix/cli/Cargo.toml
@@ -26,6 +26,7 @@ thiserror = "1.0.38"
 tokio = "1.28.0"
 tracing = "0.1.40"
 tracing-indicatif = "0.3.6"
+rustc-hash = "2.0.0"
 
 [dependencies.wu-manber]
 git = "https://github.com/tvlfyi/wu-manber.git"
diff --git a/tvix/cli/src/lib.rs b/tvix/cli/src/lib.rs
index 7686cc2c0fe8..2351da13a771 100644
--- a/tvix/cli/src/lib.rs
+++ b/tvix/cli/src/lib.rs
@@ -1,5 +1,7 @@
-use std::{collections::HashMap, path::PathBuf, rc::Rc};
+use std::path::PathBuf;
+use std::rc::Rc;
 
+use rustc_hash::FxHashMap;
 use smol_str::SmolStr;
 use std::fmt::Write;
 use tracing::{instrument, Span};
@@ -86,7 +88,7 @@ pub fn evaluate(
     path: Option<PathBuf>,
     args: &Args,
     allow_incomplete: AllowIncomplete,
-    env: Option<&HashMap<SmolStr, Value>>,
+    env: Option<&FxHashMap<SmolStr, Value>>,
     globals: Option<Rc<GlobalsMap>>,
     source_map: Option<SourceCode>,
 ) -> Result<EvalResult, IncompleteInput> {
@@ -218,7 +220,7 @@ pub fn interpret(
     args: &Args,
     explain: bool,
     allow_incomplete: AllowIncomplete,
-    env: Option<&HashMap<SmolStr, Value>>,
+    env: Option<&FxHashMap<SmolStr, Value>>,
     globals: Option<Rc<GlobalsMap>>,
     source_map: Option<SourceCode>,
 ) -> Result<InterpretResult, IncompleteInput> {
diff --git a/tvix/cli/src/repl.rs b/tvix/cli/src/repl.rs
index 601b639154a6..e4b499609829 100644
--- a/tvix/cli/src/repl.rs
+++ b/tvix/cli/src/repl.rs
@@ -1,6 +1,7 @@
+use std::path::PathBuf;
 use std::rc::Rc;
-use std::{collections::HashMap, path::PathBuf};
 
+use rustc_hash::FxHashMap;
 use rustyline::{error::ReadlineError, Editor};
 use smol_str::SmolStr;
 use tvix_eval::{GlobalsMap, SourceCode, Value};
@@ -88,7 +89,7 @@ pub struct Repl<'a> {
     multiline_input: Option<String>,
     rl: Editor<()>,
     /// Local variables defined at the top-level in the repl
-    env: HashMap<SmolStr, Value>,
+    env: FxHashMap<SmolStr, Value>,
 
     io_handle: Rc<TvixStoreIO>,
     args: &'a Args,
@@ -102,7 +103,7 @@ impl<'a> Repl<'a> {
         Self {
             multiline_input: None,
             rl,
-            env: HashMap::new(),
+            env: FxHashMap::default(),
             io_handle,
             args,
             source_map: Default::default(),