feat: add conditional compilation of methods based on the underlying …

…field being used (noir-lang#3045)

Co-authored-by: kevaundray <[email protected]>

acvm-repo/acir_field/Cargo.toml

@@ -16,6 +16,7 @@ repository.workspace = true
 hex.workspace = true
 num-bigint.workspace = true
 serde.workspace = true
+num-traits.workspace = true
 
 ark-bn254 = { version = "^0.4.0", optional = true, default-features = false, features = [
     "curve",

acvm-repo/acir_field/src/lib.rs

@@ -3,6 +3,9 @@
 #![warn(clippy::semicolon_if_nothing_returned)]
 #![cfg_attr(not(test), warn(unused_crate_dependencies, unused_extern_crates))]
 
+use num_bigint::BigUint;
+use num_traits::Num;
+
 cfg_if::cfg_if! {
     if #[cfg(feature = "bn254")] {
         mod generic_ark;
@@ -18,12 +21,33 @@ cfg_if::cfg_if! {
     }
 }
 
-#[derive(Debug)]
+#[derive(Debug, PartialEq, Eq)]
 pub enum FieldOptions {
     BN254,
     BLS12_381,
 }
 
+impl FieldOptions {
+    pub fn to_string(&self) -> &str {
+        match self {
+            FieldOptions::BN254 => "bn254",
+            FieldOptions::BLS12_381 => "bls12_381",
+        }
+    }
+
+    pub fn is_native_field(str: &str) -> bool {
+        let big_num = if let Some(hex) = str.strip_prefix("0x") {
+            BigUint::from_str_radix(hex, 16)
+        } else {
+            BigUint::from_str_radix(str, 10)
+        };
+        if let Ok(big_num) = big_num {
+            big_num == FieldElement::modulus()
+        } else {
+            CHOSEN_FIELD.to_string() == str
+        }
+    }
+}
 // This is needed because features are additive through the dependency graph; if a dependency turns on the bn254, then it
 // will be turned on in all crates that depend on it
 #[macro_export]

compiler/noirc_frontend/src/hir/def_collector/dc_mod.rs

@@ -1,5 +1,6 @@
 use std::vec;
 
+use acvm::acir::acir_field::FieldOptions;
 use fm::FileId;
 use noirc_errors::Location;
 
@@ -202,6 +203,13 @@ impl<'a> ModCollector<'a> {
         let module = ModuleId { krate, local_id: self.module_id };
 
         for function in functions {
+            // check if optional field attribute is compatible with native field
+            if let Some(field) = function.attributes().get_field_attribute() {
+                if !FieldOptions::is_native_field(&field) {
+                    continue;
+                }
+            }
+
             let name = function.name_ident().clone();
             let func_id = context.def_interner.push_empty_fn();
 

compiler/noirc_frontend/src/lexer/token.rs

@@ -397,6 +397,15 @@ impl Attributes {
             _ => None,
         })
     }
+
+    pub fn get_field_attribute(&self) -> Option<String> {
+        for secondary in &self.secondary {
+            if let SecondaryAttribute::Field(field) = secondary {
+                return Some(field.to_lowercase());
+            }
+        }
+        None
+    }
 }
 
 /// An Attribute can be either a Primary Attribute or a Secondary Attribute
@@ -468,6 +477,10 @@ impl Attribute {
                     None => return Err(malformed_scope),
                 }
             }
+            ["field", name] => {
+                validate(name)?;
+                Attribute::Secondary(SecondaryAttribute::Field(name.to_string()))
+            }
             // Secondary attributes
             ["deprecated"] => Attribute::Secondary(SecondaryAttribute::Deprecated(None)),
             ["contract_library_method"] => {
@@ -552,6 +565,7 @@ pub enum SecondaryAttribute {
     // the entry point.
     ContractLibraryMethod,
     Event,
+    Field(String),
     Custom(String),
 }
 
@@ -565,6 +579,7 @@ impl fmt::Display for SecondaryAttribute {
             SecondaryAttribute::Custom(ref k) => write!(f, "#[{k}]"),
             SecondaryAttribute::ContractLibraryMethod => write!(f, "#[contract_library_method]"),
             SecondaryAttribute::Event => write!(f, "#[event]"),
+            SecondaryAttribute::Field(ref k) => write!(f, "#[field({k})]"),
         }
     }
 }
@@ -585,7 +600,7 @@ impl AsRef<str> for SecondaryAttribute {
         match self {
             SecondaryAttribute::Deprecated(Some(string)) => string,
             SecondaryAttribute::Deprecated(None) => "",
-            SecondaryAttribute::Custom(string) => string,
+            SecondaryAttribute::Custom(string) | SecondaryAttribute::Field(string) => string,
             SecondaryAttribute::ContractLibraryMethod => "",
             SecondaryAttribute::Event => "",
         }

tooling/nargo_cli/tests/execution_success/field_attribute/Nargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "field_attribute"
+type = "bin"
+authors = [""]
+compiler_version = "0.1"
+
+[dependencies]

tooling/nargo_cli/tests/execution_success/field_attribute/Prover.toml

@@ -0,0 +1 @@
+x = "3"

tooling/nargo_cli/tests/execution_success/field_attribute/src/main.nr

@@ -0,0 +1,19 @@
+// Test integer addition: 3 + 4 = 7
+fn main(mut x: u32) {
+    assert(x > foo());
+}
+
+#[field(bn254)]
+fn foo() -> u32 {
+    1
+}
+
+#[field(23)]
+fn foo() -> u32 {
+    2
+}
+
+#[field(bls12_381)]
+fn foo() -> u32 {
+    3
+}