feat: enforce EIP-170 contract size limit (24,576 bytes) by default

CHANGELOG.md

@@ -4,6 +4,12 @@
 
 ## Unreleased
 
+## [1.5.14] - 2026-02-03
+- **Breaking**: Enforce EIP-170 contract size limit (24,576 bytes) by default.
+  - Compilation now fails if the runtime bytecode exceeds the EIP-170 limit.
+  - Use `--no-size-limit` flag to bypass this check.
+- Increase maximum loop iterations from 10,000 to 100,000.
+
 ## [1.5.13] - 2026-01-18
 - Add support for `true` and `false` keywords as constant override values via `-c` CLI flag.
   - Example: `hnc test.huff -c DEBUG=true`

Cargo.toml

@@ -11,7 +11,7 @@ license = "MIT OR Apache-2.0"
 readme = "README.md"
 repository = "https://github.com/cakevm/huff-neo"
 rust-version = "1.89"
-version = "1.5.13"
+version = "1.5.14"
 
 [workspace.dependencies]
 huff-neo-codegen = { path = "crates/codegen" }

bin/hnc/src/arguments/base.rs

@@ -85,6 +85,10 @@ pub struct HuffArgs {
     #[clap(short = 'e', long = "evm-version")]
     pub evm_version: Option<String>,
 
+    /// Skip the contract size limit check (EIP-170: 24576 bytes)
+    #[clap(long = "no-size-limit")]
+    pub no_size_limit: bool,
+
     /// Test subcommand
     #[clap(subcommand)]
     pub test: Option<TestCommands>,

bin/hnc/src/main.rs

@@ -116,6 +116,7 @@ fn main() {
         cached: use_cache,
         file_provider: Arc::new(FileSystemFileProvider {}),
         relax_jumps: cli.relax_jumps,
+        no_size_limit: cli.no_size_limit,
     };
 
     // Handle flattened source output

book/cli.md

@@ -37,6 +37,7 @@ Options:
   -t, --alt-constructor <ALT_CONSTRUCTOR> Compile a specific constructor macro
   -e, --evm-version <EVM_VERSION>         Set the EVM version [default: osaka]
       --flattened-source                  Output the flattened source code with all dependencies resolved
+      --no-size-limit                     Skip the contract size limit check (EIP-170: 24576 bytes)
   -V, --version                           Print version
   -h, --help                              Print help
 ```
@@ -122,6 +123,17 @@ Example:
 hnc ./src/ERC20.huff --flattened-source
 ```
 
+### `--no-size-limit`
+
+Passing the `--no-size-limit` flag bypasses the EIP-170 contract size limit check.
+By default, compilation fails if the runtime bytecode exceeds 24,576 bytes (the
+maximum deployable contract size on Ethereum mainnet).
+
+Example:
+```shell
+hnc ./src/LargeContract.huff -b --no-size-limit
+```
+
 ### `-g` Interface
 
 Passing the `-g` flag will generate a Solidity interface for the Huff contract

crates/codegen/README.md

@@ -40,7 +40,7 @@ fn example() {
     let main_bytecode = "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";
     let constructor_bytecode = "335f55";
     let inputs = vec![];
-    let churn_res = cg.churn(Arc::new(FileSource::default()), inputs, main_bytecode, constructor_bytecode, false, None, None);
+    let churn_res = cg.churn(Arc::new(FileSource::default()), inputs, main_bytecode, constructor_bytecode, false, None, None, false);
 
     // Validate the output bytecode
     assert_eq!(churn_res.unwrap().bytecode, "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".to_lowercase());

crates/codegen/src/irgen/statements.rs

@@ -923,7 +923,7 @@ pub fn statement_gen<'a>(
             }
 
             // Maximum iterations safety check
-            const MAX_LOOP_ITERATIONS: usize = 10_000;
+            const MAX_LOOP_ITERATIONS: usize = 100_000;
             let mut current = start_u256;
             let mut iteration_count = 0;
 

crates/codegen/src/lib.rs

@@ -38,6 +38,9 @@ pub(crate) const MAX_MACRO_RECURSION_DEPTH: usize = 100;
 /// though typical contracts converge in a few iterations.
 const JUMP_RELAXATION_MAX_ITERATIONS: usize = 20;
 
+/// EIP-170 contract size limit (24576 bytes)
+pub const EIP170_CONTRACT_SIZE_LIMIT: usize = 24576;
+
 /// Compiles Huff contracts into EVM bytecode.
 ///
 /// Transforms a Contract AST into executable bytecode, handling macro expansion,
@@ -1133,6 +1136,7 @@ impl Codegen {
     /// * `args` - A vector of Tokens representing constructor arguments
     /// * `main_bytecode` - The compiled MAIN Macro bytecode
     /// * `constructor_bytecode` - The compiled `CONSTRUCTOR` Macro bytecode
+    /// * `no_size_limit` - Skip the EIP-170 contract size limit check
     #[allow(clippy::too_many_arguments)]
     pub fn churn(
         &mut self,
@@ -1143,6 +1147,7 @@ impl Codegen {
         has_custom_bootstrap: bool,
         main_source_map: Option<Vec<SourceMapEntry>>,
         constructor_source_map: Option<Vec<SourceMapEntry>>,
+        no_size_limit: bool,
     ) -> Result<Artifact, CodegenError> {
         let artifact: &mut Artifact = if let Some(art) = &mut self.artifact {
             art
@@ -1157,6 +1162,15 @@ impl Codegen {
         let contract_length = main_bytecode.len() / 2;
         let constructor_length = constructor_bytecode.len() / 2;
 
+        // Check contract size limit (EIP-170)
+        if !no_size_limit && contract_length > EIP170_CONTRACT_SIZE_LIMIT {
+            return Err(CodegenError {
+                kind: CodegenErrorKind::ContractSizeLimitExceeded(contract_length, EIP170_CONTRACT_SIZE_LIMIT),
+                span: AstSpan(vec![Span { start: 0, end: 0, file: Some(file) }]).boxed(),
+                token: None,
+            });
+        }
+
         // Sort constructor arguments so that statically sized args are inserted last.
         args.sort_by(|a, b| {
             if a.is_dynamic() && !b.is_dynamic() {

crates/codegen/tests/churn.rs

@@ -16,7 +16,7 @@ fn churns_into_bytecode() {
     // ERC20 Bytecode
     let main_bytecode = "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";
     let constructor_bytecode = "33600055";
-    let churn_res = cg.churn(Arc::new(FileSource::default()), inputs, main_bytecode, constructor_bytecode, false, None, None);
+    let churn_res = cg.churn(Arc::new(FileSource::default()), inputs, main_bytecode, constructor_bytecode, false, None, None, false);
     assert!(churn_res.is_ok());
     assert_eq!(churn_res.unwrap().bytecode, "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".to_lowercase());
 
@@ -41,7 +41,7 @@ fn churns_custom_bootstrap() {
     let main_bytecode = "6001600216";
     // custom bootstrap code
     let constructor_bytecode = "64600160020160005260056000f3";
-    let churn_res = cg.churn(Arc::new(FileSource::default()), inputs, main_bytecode, constructor_bytecode, true, None, None);
+    let churn_res = cg.churn(Arc::new(FileSource::default()), inputs, main_bytecode, constructor_bytecode, true, None, None, false);
 
     assert!(churn_res.is_ok());
     assert_eq!(churn_res.unwrap().bytecode, "64600160020160005260056000f36001600216".to_lowercase());
@@ -61,7 +61,7 @@ fn churns_constructor_args() {
     // ERC20 Bytecode
     let main_bytecode = "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";
     let constructor_bytecode = "33600055";
-    let churn_res = cg.churn(Arc::new(FileSource::default()), inputs, main_bytecode, constructor_bytecode, false, None, None);
+    let churn_res = cg.churn(Arc::new(FileSource::default()), inputs, main_bytecode, constructor_bytecode, false, None, None, false);
     assert!(churn_res.is_ok());
     assert_ne!(churn_res.unwrap().bytecode, "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".to_lowercase());
 }

crates/core/benches/huff_benchmark.rs

@@ -96,7 +96,7 @@ fn codegen_erc20_benchmark(c: &mut Criterion) {
         // Churn
         let mut cg = Codegen::new();
         let artifact =
-            cg.churn(file_source.clone(), vec![], &main_bytecode, &constructor_bytecode, has_custom_bootstrap, None, None).unwrap();
+            cg.churn(file_source.clone(), vec![], &main_bytecode, &constructor_bytecode, has_custom_bootstrap, None, None, false).unwrap();
 
         // Full expected bytecode output (generated from huff-neo)
         let expected_bytecode = "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";
@@ -144,7 +144,7 @@ fn erc20_compilation_benchmark(c: &mut Criterion) {
         // Churn
         let mut cg = Codegen::new();
         let artifact =
-            cg.churn(file_source.clone(), vec![], &main_bytecode, &constructor_bytecode, has_custom_bootstrap, None, None).unwrap();
+            cg.churn(file_source.clone(), vec![], &main_bytecode, &constructor_bytecode, has_custom_bootstrap, None, None, false).unwrap();
 
         // Full expected bytecode output (generated from huff-neo)
         let expected_bytecode = "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";
@@ -192,7 +192,7 @@ fn erc721_compilation_benchmark(c: &mut Criterion) {
         // Churn
         let mut cg = Codegen::new();
         let artifact =
-            cg.churn(file_source.clone(), vec![], &main_bytecode, &constructor_bytecode, has_custom_bootstrap, None, None).unwrap();
+            cg.churn(file_source.clone(), vec![], &main_bytecode, &constructor_bytecode, has_custom_bootstrap, None, None, false).unwrap();
 
         // Full expected bytecode output (generated from huff-neo)
         let expected_bytecode = "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";

crates/core/src/lib.rs

@@ -84,6 +84,8 @@ pub struct Compiler<'a, 'l> {
     pub file_provider: Arc<dyn FileProvider>,
     /// Whether to apply jump relaxation optimization
     pub relax_jumps: bool,
+    /// Skip the contract size limit validation (EIP-170: 24576 bytes)
+    pub no_size_limit: bool,
 }
 
 impl<'a, 'l> Compiler<'a, 'l> {
@@ -115,6 +117,7 @@ impl<'a, 'l> Compiler<'a, 'l> {
             cached,
             file_provider: Arc::new(FileSystemFileProvider {}),
             relax_jumps: false,
+            no_size_limit: false,
         }
     }
 
@@ -146,6 +149,7 @@ impl<'a, 'l> Compiler<'a, 'l> {
             cached: false,
             file_provider: Arc::new(InMemoryFileProvider::new(file_sources)),
             relax_jumps: false,
+            no_size_limit: false,
         }
     }
 
@@ -559,6 +563,7 @@ impl<'a, 'l> Compiler<'a, 'l> {
             has_custom_bootstrap,
             Some(main_source_map),
             Some(constructor_source_map),
+            self.no_size_limit,
         );
         match churn_res {
             Ok(mut artifact) => {

crates/core/tests/builtins.rs

@@ -85,8 +85,16 @@ fn test_dyn_constructor_arg_builtin() {
     let main_code = Codegen::generate_main_bytecode(evm_version, &contract, None, false).unwrap();
 
     let args = Codegen::encode_constructor_args(vec![String::from("testing")]);
-    let final_bytecode =
-        cg.churn(Arc::new(FileSource::default()), args, main_code.as_str(), constructor_code.as_str(), has_custom_bootstrap, None, None);
+    let final_bytecode = cg.churn(
+        Arc::new(FileSource::default()),
+        args,
+        main_code.as_str(),
+        constructor_code.as_str(),
+        has_custom_bootstrap,
+        None,
+        None,
+        false,
+    );
 
     assert_eq!(
         final_bytecode.unwrap().bytecode,