feat: add MVP nargo export command (#3870)

# Description

## Problem\*

Resolves <!-- Link to GitHub Issue -->

## Summary\*

This PR adds the skeleton of a `nargo export` command which compiles all
of the functions in a library crate with the `#[export]` attribute into
an `export` directory. This is intended to be then fed into
`noir-codegen` in order to generate a TS library for executing these
functions.

## Additional Context



## Documentation\*

Check one:
- [ ] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[Exceptional Case]** Documentation to be submitted in a separate
PR.

# PR Checklist\*

- [ ] I have tested the changes locally.
- [ ] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

---------

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

.github/workflows/test-js-packages.yml

@@ -319,7 +319,7 @@ jobs:
         run: yarn workspace @noir-lang/noir_wasm test:browser
 
   test-noir-codegen:
-    needs: [build-acvm-js, build-noirc-abi]
+    needs: [build-acvm-js, build-noirc-abi, build-nargo]
     name: noir_codegen
     runs-on: ubuntu-latest
     timeout-minutes: 30
@@ -328,6 +328,12 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Download nargo binary
+        uses: actions/download-artifact@v3
+        with:
+          name: nargo
+          path: ./nargo
+
       - name: Download acvm_js package artifact
         uses: actions/download-artifact@v3
         with:
@@ -339,6 +345,14 @@ jobs:
         with:
           name: noirc_abi_wasm
           path: ./tooling/noirc_abi_wasm
+
+      - name: Set nargo on PATH
+        run: |
+          nargo_binary="${{ github.workspace }}/nargo/nargo"
+          chmod +x $nargo_binary
+          echo "$(dirname $nargo_binary)" >> $GITHUB_PATH
+          export PATH="$PATH:$(dirname $nargo_binary)"
+          nargo -V
 
       - name: Install Yarn dependencies
         uses: ./.github/actions/setup

compiler/noirc_frontend/src/hir/def_map/mod.rs

@@ -173,6 +173,29 @@ impl CrateDefMap {
             })
         })
     }
+
+    /// Go through all modules in this crate, and find all functions in
+    /// each module with the #[export] attribute
+    pub fn get_all_exported_functions<'a>(
+        &'a self,
+        interner: &'a NodeInterner,
+    ) -> impl Iterator<Item = FuncId> + 'a {
+        self.modules.iter().flat_map(|(_, module)| {
+            module.value_definitions().filter_map(|id| {
+                if let Some(func_id) = id.as_function() {
+                    let attributes = interner.function_attributes(&func_id);
+                    if attributes.secondary.contains(&SecondaryAttribute::Export) {
+                        Some(func_id)
+                    } else {
+                        None
+                    }
+                } else {
+                    None
+                }
+            })
+        })
+    }
+
     /// Go through all modules in this crate, find all `contract ... { ... }` declarations,
     /// and collect them all into a Vec.
     pub fn get_all_contracts(&self, interner: &NodeInterner) -> Vec<Contract> {

compiler/noirc_frontend/src/hir/mod.rs

@@ -194,6 +194,19 @@ impl Context<'_> {
             .collect()
     }
 
+    pub fn get_all_exported_functions_in_crate(&self, crate_id: &CrateId) -> Vec<(String, FuncId)> {
+        let interner = &self.def_interner;
+        let def_map = self.def_map(crate_id).expect("The local crate should be analyzed already");
+
+        def_map
+            .get_all_exported_functions(interner)
+            .map(|function_id| {
+                let function_name = self.function_name(&function_id).to_owned();
+                (function_name, function_id)
+            })
+            .collect()
+    }
+
     /// Return a Vec of all `contract` declarations in the source code and the functions they contain
     pub fn get_all_contracts(&self, crate_id: &CrateId) -> Vec<Contract> {
         self.def_map(crate_id)

compiler/noirc_frontend/src/lexer/token.rs

@@ -510,6 +510,7 @@ impl Attribute {
                 Attribute::Secondary(SecondaryAttribute::ContractLibraryMethod)
             }
             ["event"] => Attribute::Secondary(SecondaryAttribute::Event),
+            ["export"] => Attribute::Secondary(SecondaryAttribute::Export),
             ["deprecated", name] => {
                 if !name.starts_with('"') && !name.ends_with('"') {
                     return Err(LexerErrorKind::MalformedFuncAttribute {
@@ -588,6 +589,7 @@ pub enum SecondaryAttribute {
     // the entry point.
     ContractLibraryMethod,
     Event,
+    Export,
     Field(String),
     Custom(String),
 }
@@ -602,6 +604,7 @@ 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::Export => write!(f, "#[export]"),
             SecondaryAttribute::Field(ref k) => write!(f, "#[field({k})]"),
         }
     }
@@ -625,7 +628,7 @@ impl AsRef<str> for SecondaryAttribute {
             SecondaryAttribute::Deprecated(None) => "",
             SecondaryAttribute::Custom(string) | SecondaryAttribute::Field(string) => string,
             SecondaryAttribute::ContractLibraryMethod => "",
-            SecondaryAttribute::Event => "",
+            SecondaryAttribute::Event | SecondaryAttribute::Export => "",
         }
     }
 }

cspell.json

@@ -15,8 +15,8 @@
         "bincode",
         "bindgen",
         "bitand",
-        "bitxor",
         "bitor",
+        "bitxor",
         "blackbox",
         "bridgekeeper",
         "brillig",
@@ -29,6 +29,7 @@
         "chumsky",
         "clippy",
         "codegen",
+        "codegenned",
         "codegens",
         "Codespaces",
         "codespan",

tooling/nargo/src/constants.rs

@@ -7,6 +7,8 @@ pub const PROOFS_DIR: &str = "proofs";
 pub const SRC_DIR: &str = "src";
 /// The directory to store circuits' serialized ACIR representations.
 pub const TARGET_DIR: &str = "target";
+/// The directory to store serialized ACIR representations of exported library functions.
+pub const EXPORT_DIR: &str = "export";
 
 // Files
 /// The file from which Nargo pulls prover inputs

tooling/nargo/src/workspace.rs

@@ -10,7 +10,7 @@ use std::{
 };
 
 use crate::{
-    constants::{CONTRACT_DIR, PROOFS_DIR, TARGET_DIR},
+    constants::{CONTRACT_DIR, EXPORT_DIR, PROOFS_DIR, TARGET_DIR},
     package::Package,
 };
 
@@ -40,6 +40,10 @@ impl Workspace {
     pub fn target_directory_path(&self) -> PathBuf {
         self.root_dir.join(TARGET_DIR)
     }
+
+    pub fn export_directory_path(&self) -> PathBuf {
+        self.root_dir.join(EXPORT_DIR)
+    }
 }
 
 pub enum IntoIter<'a, T> {

tooling/nargo_cli/src/cli/compile_cmd.rs

@@ -232,7 +232,7 @@ fn compile_contract(
     Ok((optimized_contract, warnings))
 }
 
-fn save_program(
+pub(super) fn save_program(
     program: CompiledProgram,
     package: &Package,
     circuit_dir: &Path,

tooling/nargo_cli/src/cli/export_cmd.rs

@@ -0,0 +1,120 @@
+use nargo::errors::CompileError;
+use noirc_errors::FileDiagnostic;
+use rayon::prelude::*;
+
+use fm::FileManager;
+use iter_extended::try_vecmap;
+use nargo::insert_all_files_for_workspace_into_file_manager;
+use nargo::package::Package;
+use nargo::prepare_package;
+use nargo::workspace::Workspace;
+use nargo_toml::{get_package_manifest, resolve_workspace_from_toml, PackageSelection};
+use noirc_driver::{
+    compile_no_check, file_manager_with_stdlib, CompileOptions, CompiledProgram,
+    NOIR_ARTIFACT_VERSION_STRING,
+};
+
+use noirc_frontend::graph::CrateName;
+
+use clap::Args;
+
+use crate::backends::Backend;
+use crate::errors::CliError;
+
+use super::check_cmd::check_crate_and_report_errors;
+
+use super::compile_cmd::report_errors;
+use super::fs::program::save_program_to_file;
+use super::NargoConfig;
+
+/// Exports functions marked with #[export] attribute
+#[derive(Debug, Clone, Args)]
+pub(crate) struct ExportCommand {
+    /// The name of the package to compile
+    #[clap(long, conflicts_with = "workspace")]
+    package: Option<CrateName>,
+
+    /// Compile all packages in the workspace
+    #[clap(long, conflicts_with = "package")]
+    workspace: bool,
+
+    #[clap(flatten)]
+    compile_options: CompileOptions,
+}
+
+pub(crate) fn run(
+    _backend: &Backend,
+    args: ExportCommand,
+    config: NargoConfig,
+) -> Result<(), CliError> {
+    let toml_path = get_package_manifest(&config.program_dir)?;
+    let default_selection =
+        if args.workspace { PackageSelection::All } else { PackageSelection::DefaultOrAll };
+    let selection = args.package.map_or(default_selection, PackageSelection::Selected);
+
+    let workspace = resolve_workspace_from_toml(
+        &toml_path,
+        selection,
+        Some(NOIR_ARTIFACT_VERSION_STRING.to_owned()),
+    )?;
+
+    let mut workspace_file_manager = file_manager_with_stdlib(&workspace.root_dir);
+    insert_all_files_for_workspace_into_file_manager(&workspace, &mut workspace_file_manager);
+
+    let library_packages: Vec<_> =
+        workspace.into_iter().filter(|package| package.is_library()).collect();
+
+    library_packages
+        .par_iter()
+        .map(|package| {
+            compile_exported_functions(
+                &workspace_file_manager,
+                &workspace,
+                package,
+                &args.compile_options,
+            )
+        })
+        .collect()
+}
+
+fn compile_exported_functions(
+    file_manager: &FileManager,
+    workspace: &Workspace,
+    package: &Package,
+    compile_options: &CompileOptions,
+) -> Result<(), CliError> {
+    let (mut context, crate_id) = prepare_package(file_manager, package);
+    check_crate_and_report_errors(
+        &mut context,
+        crate_id,
+        compile_options.deny_warnings,
+        compile_options.disable_macros,
+        compile_options.silence_warnings,
+    )?;
+
+    let exported_functions = context.get_all_exported_functions_in_crate(&crate_id);
+
+    let exported_programs = try_vecmap(
+        exported_functions,
+        |(function_name, function_id)| -> Result<(String, CompiledProgram), CompileError> {
+            // TODO: We should to refactor how to deal with compilation errors to avoid this.
+            let program = compile_no_check(&context, compile_options, function_id, None, false)
+                .map_err(|error| vec![FileDiagnostic::from(error)]);
+
+            let program = report_errors(
+                program.map(|program| (program, Vec::new())),
+                file_manager,
+                compile_options.deny_warnings,
+                compile_options.silence_warnings,
+            )?;
+
+            Ok((function_name, program))
+        },
+    )?;
+
+    let export_dir = workspace.export_directory_path();
+    for (function_name, program) in exported_programs {
+        save_program_to_file(&program.into(), &function_name.parse().unwrap(), &export_dir);
+    }
+    Ok(())
+}

tooling/nargo_cli/src/cli/mod.rs

@@ -17,6 +17,7 @@ mod compile_cmd;
 mod dap_cmd;
 mod debug_cmd;
 mod execute_cmd;
+mod export_cmd;
 mod fmt_cmd;
 mod info_cmd;
 mod init_cmd;
@@ -69,6 +70,8 @@ enum NargoCommand {
     Init(init_cmd::InitCommand),
     Execute(execute_cmd::ExecuteCommand),
     #[command(hide = true)] // Hidden while the feature is being built out
+    Export(export_cmd::ExportCommand),
+    #[command(hide = true)] // Hidden while the feature is being built out
     Debug(debug_cmd::DebugCommand),
     Prove(prove_cmd::ProveCommand),
     Verify(verify_cmd::VerifyCommand),
@@ -109,6 +112,7 @@ pub(crate) fn start_cli() -> eyre::Result<()> {
         NargoCommand::Compile(args) => compile_cmd::run(&backend, args, config),
         NargoCommand::Debug(args) => debug_cmd::run(&backend, args, config),
         NargoCommand::Execute(args) => execute_cmd::run(&backend, args, config),
+        NargoCommand::Export(args) => export_cmd::run(&backend, args, config),
         NargoCommand::Prove(args) => prove_cmd::run(&backend, args, config),
         NargoCommand::Verify(args) => verify_cmd::run(&backend, args, config),
         NargoCommand::Test(args) => test_cmd::run(&backend, args, config),

tooling/noir_codegen/.gitignore

@@ -1,5 +1,4 @@
 crs
 lib
 
-!test/*/target
 test/codegen

tooling/noir_codegen/package.json

@@ -36,9 +36,9 @@
     "dev": "tsc-multi --watch",
     "build": "tsc",
     "test": "yarn test:codegen && yarn test:node && yarn test:clean",
-    "test:codegen": "tsx src/main.ts ./test/assert_lt/target/** --out-dir ./test/codegen",
+    "test:codegen": "nargo export --program-dir=./test/test_lib && tsx src/main.ts ./test/test_lib/export/** --out-dir ./test/codegen",
     "test:node": "mocha --timeout 25000 --exit --config ./.mocharc.json",
-    "test:clean": "rm -rf ./test/codegen",
+    "test:clean": "rm -rf ./test/codegen ./test/test_lib/export",
     "prettier": "prettier 'src/**/*.ts'",
     "prettier:fix": "prettier --write 'src/**/*.ts' 'test/**/*.ts'",
     "lint": "NODE_NO_WARNINGS=1 eslint . --ext .ts --ignore-path ./.eslintignore  --max-warnings 0",

tooling/noir_codegen/test/index.test.ts

@@ -1,10 +1,12 @@
 import { expect } from 'chai';
-import { assert_lt, MyStruct, u64, ForeignCallHandler } from './codegen/index.js';
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+// @ts-ignore File is codegenned at test time.
+import { exported_function_foo, MyStruct, u64, ForeignCallHandler } from './codegen/index.js';
 
 it('codegens a callable function', async () => {
   const my_struct = { foo: true, bar: ['12345', '12345', '12345'] };
 
-  const [sum, constant, struct]: [u64, u64, MyStruct] = await assert_lt(
+  const [sum, constant, struct]: [u64, u64, MyStruct] = await exported_function_foo(
     '2',
     '3',
     [0, 0, 0, 0, 0],
@@ -35,7 +37,7 @@ it('allows passing a custom foreign call handler', async () => {
 
   const my_struct = { foo: true, bar: ['12345', '12345', '12345'] };
 
-  const [sum, constant, struct]: [u64, u64, MyStruct] = await assert_lt(
+  const [sum, constant, struct]: [u64, u64, MyStruct] = await exported_function_foo(
     '2',
     '3',
     [0, 0, 0, 0, 0],

tooling/noir_codegen/test/assert_lt/Nargo.toml → tooling/noir_codegen/test/test_lib/Nargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "assert_lt"
-type = "bin"
+name = "test_lib"
+type = "lib"
 authors = [""]
 [dependencies]

tooling/noir_codegen/test/assert_lt/src/main.nr → tooling/noir_codegen/test/test_lib/src/lib.nr

@@ -9,13 +9,8 @@ struct NestedStruct {
     baz: u64
 }
 
-fn main(
-    x: u64,
-    y: pub u64,
-    array: [u8; 5],
-    my_struct: NestedStruct,
-    string: str<5>
-) -> pub (u64, u64, MyStruct) {
+#[export]
+fn exported_function_foo(x: u64, y: u64, array: [u8; 5], my_struct: NestedStruct, string: str<5>) -> (u64, u64, MyStruct) {
     assert(array.len() == 5);
     assert(my_struct.foo.foo);
     assert(string == "12345");
@@ -24,3 +19,8 @@ fn main(
     assert(x < y);
     (x + y, 3, my_struct.foo)
 }
+
+#[export]
+fn exported_function_bar(my_struct: NestedStruct) -> (u64) {
+    my_struct.baz
+}