From b6b2ee3fb3a0b56852e02214c0538ad30ffc2cbe Mon Sep 17 00:00:00 2001
From: Philip Monk <phil@pcmonk.me>
Date: Tue, 21 Feb 2023 21:00:16 -0700
Subject: [PATCH] [ares] assert no allocation during interpret

---
 rust/ares/Cargo.lock         | 7 +++++++
 rust/ares/Cargo.toml         | 1 +
 rust/ares/src/interpreter.rs | 5 +++--
 rust/ares/src/main.rs        | 5 +++++
 4 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/rust/ares/Cargo.lock b/rust/ares/Cargo.lock
index 93df99f..c4cacef 100644
--- a/rust/ares/Cargo.lock
+++ b/rust/ares/Cargo.lock
@@ -13,6 +13,7 @@ name = "ares"
 version = "0.1.0"
 dependencies = [
  "ares_macros",
+ "assert_no_alloc",
  "bitvec",
  "criterion",
  "either",
@@ -33,6 +34,12 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "assert_no_alloc"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55ca83137a482d61d916ceb1eba52a684f98004f18e0cafea230fe5579c178a3"
+
 [[package]]
 name = "atty"
 version = "0.2.14"
diff --git a/rust/ares/Cargo.toml b/rust/ares/Cargo.toml
index 3a1cce5..5ad9637 100644
--- a/rust/ares/Cargo.toml
+++ b/rust/ares/Cargo.toml
@@ -18,6 +18,7 @@ num-traits = "0.2"
 num-derive = "0.3"
 criterion = "0.4"
 ibig = "0.3.6"
+assert_no_alloc = "1.1.2"
 
 [[bin]]
 name = "cue_pill"
diff --git a/rust/ares/src/interpreter.rs b/rust/ares/src/interpreter.rs
index 3e3e6d2..f2efcc5 100644
--- a/rust/ares/src/interpreter.rs
+++ b/rust/ares/src/interpreter.rs
@@ -5,6 +5,7 @@ use crate::mem::NockStack;
 use crate::newt::Newt;
 use crate::noun::{Atom, Cell, DirectAtom, IndirectAtom, Noun};
 use ares_macros::tas;
+use assert_no_alloc::assert_no_alloc;
 use bitvec::prelude::{BitSlice, Lsb0};
 use either::Either::*;
 use num_traits::cast::{FromPrimitive, ToPrimitive};
@@ -80,7 +81,7 @@ pub fn interpret(
         *(stack.local_noun_pointer(0)) = work_to_noun(Done);
     }
     push_formula(stack, formula);
-    loop {
+    assert_no_alloc(|| loop {
         match unsafe { noun_to_work(*(stack.local_noun_pointer(0))) } {
             Done => {
                 stack.pop(&mut res);
@@ -350,7 +351,7 @@ pub fn interpret(
                 stack.pop(&mut res);
             }
         };
-    }
+    });
     res
 }
 
diff --git a/rust/ares/src/main.rs b/rust/ares/src/main.rs
index bace6be..2502fe5 100644
--- a/rust/ares/src/main.rs
+++ b/rust/ares/src/main.rs
@@ -3,6 +3,7 @@ use ares::mem::NockStack;
 use ares::noun::IndirectAtom;
 use ares::serf::serf;
 use ares::serialization::{cue, jam};
+use assert_no_alloc::AllocDisabler;
 use memmap::Mmap;
 use memmap::MmapMut;
 use std::env;
@@ -13,6 +14,10 @@ use std::mem;
 use std::ptr::copy_nonoverlapping;
 use std::ptr::write_bytes;
 
+#[cfg(debug_assertions)]
+#[global_allocator]
+static A: AllocDisabler = AllocDisabler;
+
 fn main() -> io::Result<()> {
     let filename = env::args().nth(1).expect("Must provide input filename");