cleanup: turn off tco feature

Author: jonathanpwang

crates/cli/src/lib.rs

@@ -1,3 +1,6 @@
+#![cfg_attr(feature = "tco", allow(incomplete_features))]
+#![cfg_attr(feature = "tco", feature(explicit_tail_calls))]
+
 pub mod commands;
 pub mod default;
 pub mod input;

crates/sdk/Cargo.toml

@@ -61,7 +61,7 @@ rrs-lib.workspace = true
 num-bigint.workspace = true
 
 [features]
-default = ["parallel", "jemalloc", "tco"]
+default = ["parallel", "jemalloc"]
 evm-prove = [
     "openvm-continuations/static-verifier",
     "openvm-native-recursion/evm-prove",

crates/sdk/src/lib.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(feature = "tco", allow(incomplete_features))]
+#![cfg_attr(feature = "tco", feature(explicit_tail_calls))]
 use std::{
     borrow::Borrow,
     fs::read,

crates/vm/Cargo.toml

@@ -50,7 +50,7 @@ openvm-native-compiler.workspace = true
 openvm-rv32im-transpiler.workspace = true
 
 [features]
-default = ["parallel", "jemalloc", "tco"]
+default = ["parallel", "jemalloc"]
 parallel = [
     "openvm-stark-backend/parallel",
     "dashmap/rayon",

crates/vm/derive/Cargo.toml

@@ -14,3 +14,6 @@ syn = { version = "2.0", features = ["parsing", "full"] }
 quote = "1.0"
 proc-macro2 = "1.0"
 itertools = { workspace = true }
+
+[features]
+tco = []

crates/vm/derive/src/lib.rs

@@ -9,6 +9,7 @@ use syn::{
     GenericParam, Ident, Meta, Token,
 };
 
+#[cfg(feature = "tco")]
 mod tco;
 
 #[proc_macro_derive(PreflightExecutor)]
@@ -772,7 +773,7 @@ fn parse_executor_type(
 ///
 /// Place this attribute above a function definition:
 /// ```
-/// #[create_tco_handler = "handler_name"]
+/// #[create_tco_handler]
 /// unsafe fn execute_e1_impl<F: PrimeField32, CTX, const B_IS_IMM: bool>(
 ///     pre_compute: &[u8],
 ///     state: &mut VmExecState<F, GuestMemory, CTX>,
@@ -793,5 +794,12 @@ fn parse_executor_type(
 /// check.
 #[proc_macro_attribute]
 pub fn create_tco_handler(_attr: TokenStream, item: TokenStream) -> TokenStream {
-    tco::tco_impl(item)
+    #[cfg(feature = "tco")]
+    {
+        tco::tco_impl(item)
+    }
+    #[cfg(not(feature = "tco"))]
+    {
+        item
+    }
 }

crates/vm/derive/src/tco.rs

@@ -67,6 +67,9 @@ pub fn tco_impl(item: TokenStream) -> TokenStream {
             }
             let next_handler = next_handler.unwrap_unchecked();
 
+            // NOTE: `become` is a keyword that requires Rust Nightly.
+            // It is part of the explicit tail calls RFC: <https://github.com/rust-lang/rust/issues/112788>
+            // which is still incomplete.
             become next_handler(interpreter, exec_state)
         }
     };

crates/vm/src/arch/interpreter.rs

@@ -50,7 +50,7 @@ pub struct InterpretedInstance<'a, F, Ctx> {
     pre_compute_max_size: usize,
     /// Handler function pointers for tail call optimization.
     #[cfg(feature = "tco")]
-    handlers: Vec<Handler<F, Ctx>>, // *const ()>,
+    handlers: Vec<Handler<F, Ctx>>,
 
     pc_base: u32,
     pc_start: u32,

extensions/algebra/circuit/Cargo.toml

@@ -7,11 +7,6 @@ edition.workspace = true
 homepage.workspace = true
 repository.workspace = true
 
-[features]
-default = ["jemalloc", "tco"]
-tco = ["openvm-rv32im-circuit/tco"]
-jemalloc = ["openvm-circuit/jemalloc"]
-
 [dependencies]
 openvm-circuit-primitives = { workspace = true }
 openvm-circuit-primitives-derive = { workspace = true }
@@ -43,5 +38,9 @@ openvm-rv32-adapters = { workspace = true, features = ["test-utils"] }
 openvm-pairing-guest = { workspace = true, features = ["halo2curves"] }
 test-case = { workspace = true }
 
+[features]
+default = []
+tco = ["openvm-rv32im-circuit/tco"]
+
 [package.metadata.cargo-shear]
 ignored = ["derive_more"]

extensions/algebra/circuit/src/execution.rs

@@ -336,6 +336,7 @@ impl<F: PrimeField32, const BLOCKS: usize, const BLOCK_SIZE: usize, const IS_FP2
         )
     }
 
+    #[cfg(feature = "tco")]
     fn metered_handler<Ctx>(
         &self,
         chip_idx: usize,