Introduce a consteval_int macro to compute integers at compile-time

crates/cairo-lang-plugins/Cargo.toml

@@ -16,6 +16,7 @@ cairo-lang-syntax = { path = "../cairo-lang-syntax", version = "2.0.0-rc0" }
 cairo-lang-utils = { path = "../cairo-lang-utils", version = "2.0.0-rc0" }
 indoc.workspace = true
 itertools.workspace = true
+num-bigint.workspace = true
 salsa.workspace = true
 smol_str.workspace = true
 

crates/cairo-lang-plugins/src/lib.rs

@@ -3,7 +3,9 @@ use std::sync::Arc;
 
 use cairo_lang_semantic::plugin::SemanticPlugin;
 
-use crate::plugins::{ConfigPlugin, DerivePlugin, GenerateTraitPlugin, PanicablePlugin};
+use crate::plugins::{
+    ConfigPlugin, ConstevalIntMacroPlugin, DerivePlugin, GenerateTraitPlugin, PanicablePlugin,
+};
 
 pub mod plugins;
 
@@ -13,6 +15,7 @@ mod test;
 /// Gets the list of default plugins to load into the Cairo compiler.
 pub fn get_default_plugins() -> Vec<Arc<dyn SemanticPlugin>> {
     vec![
+        Arc::new(ConstevalIntMacroPlugin::default()),
         Arc::new(DerivePlugin::default()),
         Arc::new(GenerateTraitPlugin::default()),
         Arc::new(PanicablePlugin::default()),

crates/cairo-lang-plugins/src/plugins/consteval_int.rs

@@ -0,0 +1,170 @@
+use std::sync::Arc;
+
+use cairo_lang_defs::plugin::{
+    DynGeneratedFileAuxData, MacroPlugin, PluginDiagnostic, PluginGeneratedFile, PluginResult,
+};
+use cairo_lang_semantic::plugin::{AsDynMacroPlugin, SemanticPlugin, TrivialPluginAuxData};
+use cairo_lang_syntax::node::db::SyntaxGroup;
+use cairo_lang_syntax::node::{ast, Terminal, TypedSyntaxNode};
+use num_bigint::BigInt;
+
+#[derive(Debug, Default)]
+#[non_exhaustive]
+pub struct ConstevalIntMacroPlugin;
+
+impl AsDynMacroPlugin for ConstevalIntMacroPlugin {
+    fn as_dyn_macro_plugin<'a>(self: Arc<Self>) -> Arc<dyn MacroPlugin + 'a>
+    where
+        Self: 'a,
+    {
+        self
+    }
+}
+impl SemanticPlugin for ConstevalIntMacroPlugin {}
+
+impl MacroPlugin for ConstevalIntMacroPlugin {
+    fn generate_code(&self, db: &dyn SyntaxGroup, item_ast: ast::Item) -> PluginResult {
+        match item_ast {
+            ast::Item::Constant(constant_ast) => handle_constant(db, &constant_ast),
+            _ => PluginResult::default(),
+        }
+    }
+}
+
+/// Rewrite a constant declaration that contains a consteval_int macro
+/// into a constant declaration with the computed value,
+/// e.g. `const a: felt252 = consteval_int!(2 * 2 * 2);` into `const a: felt252 = 8;`.
+fn handle_constant(db: &dyn SyntaxGroup, constant_ast: &ast::ItemConstant) -> PluginResult {
+    let constant_value = constant_ast.value(db);
+    if let ast::Expr::InlineMacro(inline_macro) = constant_value {
+        if inline_macro.path(db).as_syntax_node().get_text(db) != "consteval_int" {
+            return PluginResult::default();
+        }
+        let mut diagnostics = vec![];
+        let constant_expression =
+            extract_consteval_macro_expression(db, &inline_macro, &mut diagnostics);
+        if constant_expression.is_none() {
+            return PluginResult { diagnostics, ..Default::default() };
+        }
+        let new_value = compute_constant_expr(db, &constant_expression.unwrap(), &mut diagnostics);
+        if new_value.is_none() {
+            return PluginResult { diagnostics, ..Default::default() };
+        }
+        return PluginResult {
+            code: Some(PluginGeneratedFile {
+                name: "computed_constants".into(),
+                content: format!(
+                    "const {}{}= {};",
+                    constant_ast.name(db).text(db),
+                    constant_ast.type_clause(db).as_syntax_node().get_text(db),
+                    new_value.unwrap()
+                ),
+                aux_data: DynGeneratedFileAuxData(Arc::new(TrivialPluginAuxData {})),
+            }),
+            diagnostics,
+            remove_original_item: true,
+        };
+    }
+    PluginResult::default()
+}
+
+/// Extract the actual expression from the consteval_int macro, or fail with diagnostics.
+fn extract_consteval_macro_expression(
+    db: &dyn SyntaxGroup,
+    macro_ast: &ast::ExprInlineMacro,
+    diagnostics: &mut Vec<PluginDiagnostic>,
+) -> Option<ast::Expr> {
+    let args = macro_ast.arguments(db).args(db).elements(db);
+    if args.len() != 1 {
+        diagnostics.push(PluginDiagnostic {
+            stable_ptr: macro_ast.stable_ptr().untyped(),
+            message: "consteval_int macro must have a single unnamed argument.".to_string(),
+        });
+        return None;
+    }
+    match args[0].arg_clause(db) {
+        ast::ArgClause::Unnamed(arg) => Some(arg.value(db)),
+        _ => {
+            diagnostics.push(PluginDiagnostic {
+                stable_ptr: macro_ast.stable_ptr().untyped(),
+                message: "consteval_int macro must have a single unnamed argument.".to_string(),
+            });
+            None
+        }
+    }
+}
+
+/// Compute the actual value of an integer expression, or fail with diagnostics.
+/// This computation handles arbitrary integers, unlike regular Cairo math.
+fn compute_constant_expr(
+    db: &dyn SyntaxGroup,
+    value: &ast::Expr,
+    diagnostics: &mut Vec<PluginDiagnostic>,
+) -> Option<BigInt> {
+    match value {
+        ast::Expr::Literal(lit) => lit.numeric_value(db),
+        ast::Expr::Binary(bin_expr) => match bin_expr.op(db) {
+            ast::BinaryOperator::Plus(_) => Some(
+                compute_constant_expr(db, &bin_expr.lhs(db), diagnostics)?
+                    + compute_constant_expr(db, &bin_expr.rhs(db), diagnostics)?,
+            ),
+            ast::BinaryOperator::Mul(_) => Some(
+                compute_constant_expr(db, &bin_expr.lhs(db), diagnostics)?
+                    * compute_constant_expr(db, &bin_expr.rhs(db), diagnostics)?,
+            ),
+            ast::BinaryOperator::Minus(_) => Some(
+                compute_constant_expr(db, &bin_expr.lhs(db), diagnostics)?
+                    - compute_constant_expr(db, &bin_expr.rhs(db), diagnostics)?,
+            ),
+            ast::BinaryOperator::Div(_) => Some(
+                compute_constant_expr(db, &bin_expr.lhs(db), diagnostics)?
+                    / compute_constant_expr(db, &bin_expr.rhs(db), diagnostics)?,
+            ),
+            ast::BinaryOperator::Mod(_) => Some(
+                compute_constant_expr(db, &bin_expr.lhs(db), diagnostics)?
+                    % compute_constant_expr(db, &bin_expr.rhs(db), diagnostics)?,
+            ),
+            ast::BinaryOperator::And(_) => Some(
+                compute_constant_expr(db, &bin_expr.lhs(db), diagnostics)?
+                    & compute_constant_expr(db, &bin_expr.rhs(db), diagnostics)?,
+            ),
+            ast::BinaryOperator::Or(_) => Some(
+                compute_constant_expr(db, &bin_expr.lhs(db), diagnostics)?
+                    | compute_constant_expr(db, &bin_expr.rhs(db), diagnostics)?,
+            ),
+            ast::BinaryOperator::Xor(_) => Some(
+                compute_constant_expr(db, &bin_expr.lhs(db), diagnostics)?
+                    ^ compute_constant_expr(db, &bin_expr.rhs(db), diagnostics)?,
+            ),
+            _ => {
+                diagnostics.push(PluginDiagnostic {
+                    stable_ptr: bin_expr.stable_ptr().untyped(),
+                    message: "Unsupported binary operator in consteval_int macro".to_string(),
+                });
+                None
+            }
+        },
+        ast::Expr::Unary(un_expr) => match un_expr.op(db) {
+            ast::UnaryOperator::Minus(_) => {
+                Some(-compute_constant_expr(db, &un_expr.expr(db), diagnostics)?)
+            }
+            _ => {
+                diagnostics.push(PluginDiagnostic {
+                    stable_ptr: un_expr.stable_ptr().untyped(),
+                    message: "Unsupported unary operator in consteval_int macro".to_string(),
+                });
+                None
+            }
+        },
+        ast::Expr::Parenthesized(paren_expr) => {
+            compute_constant_expr(db, &paren_expr.expr(db), diagnostics)
+        }
+        _ => {
+            diagnostics.push(PluginDiagnostic {
+                stable_ptr: value.stable_ptr().untyped(),
+                message: "Unsupported expression in consteval_int macro".to_string(),
+            });
+            None
+        }
+    }
+}

crates/cairo-lang-plugins/src/plugins/mod.rs

@@ -1,9 +1,11 @@
 pub use config::*;
+pub use consteval_int::*;
 pub use derive::*;
 pub use generate_trait::*;
 pub use panicable::*;
 
 mod config;
+mod consteval_int;
 mod derive;
 mod generate_trait;
 mod panicable;

crates/cairo-lang-plugins/src/test.rs

@@ -15,6 +15,7 @@ cairo_lang_test_utils::test_file_test!(
     expand_plugin,
     "src/test_data",
     {
+        consteval_int: "consteval_int",
         config: "config",
         derive: "derive",
         generate_trait: "generate_trait",

crates/cairo-lang-plugins/src/test_data/consteval_int

@@ -0,0 +1,107 @@
+//! > Test consteval_int! macro
+
+//! > test_runner_name
+test_expand_plugin
+
+//! > cairo_code
+const a: felt252 = 0;
+
+const b: felt252 = consteval_int!(4 + 5);
+
+const c: felt252 = 4 + 5;
+
+const d: felt252 = consteval_int!(23 + 4 * 5 + (4 + 5) / 2);
+
+const e: u8 = consteval_int!(255 + 1 - 1);
+
+//! > generated_cairo_code
+const a: felt252 = 0;
+
+const b: felt252 = 9;
+
+const c: felt252 = 4 + 5;
+
+const d: felt252 = 47;
+const e: u8 = 255;
+
+//! > expected_diagnostics
+
+//! > ==========================================================================
+
+//! > Test bad consteval_int! macros
+
+//! > test_runner_name
+test_expand_plugin
+
+//! > cairo_code
+const a: felt252 = consteval_int!(func_call(24));
+
+const b: felt252 = consteval_int!('some string');
+
+const c: felt252 = consteval_int!(*24);
+
+const d: felt252 = consteval_int!(~24);
+
+const e: felt252 = consteval_int!(234 < 5);
+
+//! > generated_cairo_code
+const a: felt252 = consteval_int!(func_call(24));
+
+
+const b: felt252 = consteval_int!('some string');
+
+
+const c: felt252 = consteval_int!(*24);
+
+
+const d: felt252 = consteval_int!(~24);
+
+
+const e: felt252 = consteval_int!(234 < 5);
+
+//! > expected_diagnostics
+error: Unsupported expression in consteval_int macro
+ --> dummy_file.cairo:1:35
+const a: felt252 = consteval_int!(func_call(24));
+                                  ^***********^
+
+error: Unsupported expression in consteval_int macro
+ --> dummy_file.cairo:3:35
+const b: felt252 = consteval_int!('some string');
+                                  ^***********^
+
+error: Unsupported unary operator in consteval_int macro
+ --> dummy_file.cairo:5:35
+const c: felt252 = consteval_int!(*24);
+                                  ^*^
+
+error: Unsupported unary operator in consteval_int macro
+ --> dummy_file.cairo:7:35
+const d: felt252 = consteval_int!(~24);
+                                  ^*^
+
+error: Unsupported binary operator in consteval_int macro
+ --> dummy_file.cairo:9:35
+const e: felt252 = consteval_int!(234 < 5);
+                                  ^*****^
+
+//! > ==========================================================================
+
+//! > Test consteval_int! inside functions (currently does nothing)
+
+//! > test_runner_name
+test_expand_plugin
+
+//! > cairo_code
+fn some_func()
+{
+    return consteval_int!(4 + 5);
+}
+
+//! > generated_cairo_code
+fn some_func()
+{
+    return consteval_int!(4 + 5);
+}
+
+//! > expected_diagnostics

tests/bug_samples/issue3130.cairo

@@ -0,0 +1,7 @@
+const a: felt252 = consteval_int!((4 + 2 * 3) * 256);
+const b: felt252 = consteval_int!(0xff & (24 + 5 * 2));
+const c: felt252 = consteval_int!(-0xff & (24 + 5 * 2));
+const d: felt252 = consteval_int!(0xff | (24 + 5 * 2));
+
+#[test]
+fn main() {}

tests/bug_samples/lib.cairo

@@ -16,6 +16,7 @@ mod issue2939;
 mod issue2961;
 mod issue2964;
 mod issue2995;
+mod issue3130;
 mod issue3153;
 mod issue3192;
 mod issue3211;