feat: add support for overriding expression width (#4117)

# Description

## Problem\*

Resolves #3854 

## Summary\*

This PR adds the `expression-width` option to the CLI which allows users
to specify the expression width they want to use. Passing zero will
result in an unbounded width.

## 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 <kevtheappdev@gmail.com>

acvm-repo/acvm/src/lib.rs

@@ -31,3 +31,13 @@ pub enum ExpressionWidth {
     Unbounded,
     Bounded { width: usize },
 }
+
+impl From<usize> for ExpressionWidth {
+    fn from(width: usize) -> ExpressionWidth {
+        if width == 0 {
+            ExpressionWidth::Unbounded
+        } else {
+            ExpressionWidth::Bounded { width }
+        }
+    }
+}

compiler/noirc_driver/src/lib.rs

@@ -3,6 +3,7 @@
 #![warn(unreachable_pub)]
 #![warn(clippy::semicolon_if_nothing_returned)]
 
+use acvm::ExpressionWidth;
 use clap::Args;
 use fm::{FileId, FileManager};
 use iter_extended::vecmap;
@@ -16,7 +17,6 @@ use noirc_frontend::hir::Context;
 use noirc_frontend::macros_api::MacroProcessor;
 use noirc_frontend::monomorphization::monomorphize;
 use noirc_frontend::node_interner::FuncId;
-use serde::{Deserialize, Serialize};
 use std::path::Path;
 use tracing::info;
 
@@ -43,8 +43,12 @@ pub const NOIRC_VERSION: &str = env!("CARGO_PKG_VERSION");
 pub const NOIR_ARTIFACT_VERSION_STRING: &str =
     concat!(env!("CARGO_PKG_VERSION"), "+", env!("GIT_COMMIT"));
 
-#[derive(Args, Clone, Debug, Default, Serialize, Deserialize)]
+#[derive(Args, Clone, Debug, Default)]
 pub struct CompileOptions {
+    /// Override the expression width requested by the backend.
+    #[arg(long, value_parser = parse_expression_width)]
+    pub expression_width: Option<ExpressionWidth>,
+
     /// Force a full recompilation.
     #[arg(long = "force")]
     pub force_compile: bool,
@@ -81,6 +85,16 @@ pub struct CompileOptions {
     pub show_monomorphized: bool,
 }
 
+fn parse_expression_width(input: &str) -> Result<ExpressionWidth, std::io::Error> {
+    use std::io::{Error, ErrorKind};
+
+    let width = input
+        .parse::<usize>()
+        .map_err(|err| Error::new(ErrorKind::InvalidInput, err.to_string()))?;
+
+    Ok(ExpressionWidth::from(width))
+}
+
 /// Helper type used to signify where only warnings are expected in file diagnostics
 pub type Warnings = Vec<FileDiagnostic>;
 

tooling/nargo_cli/src/cli/compile_cmd.rs

@@ -61,7 +61,10 @@ pub(crate) fn run(
     insert_all_files_for_workspace_into_file_manager(&workspace, &mut workspace_file_manager);
     let parsed_files = parse_all(&workspace_file_manager);
 
-    let expression_width = backend.get_backend_info_or_default();
+    let expression_width = args
+        .compile_options
+        .expression_width
+        .unwrap_or_else(|| backend.get_backend_info_or_default());
     let (compiled_program, compiled_contracts) = compile_workspace(
         &workspace_file_manager,
         &parsed_files,

tooling/nargo_cli/src/cli/dap_cmd.rs

@@ -1,4 +1,5 @@
 use acvm::acir::native_types::WitnessMap;
+use acvm::ExpressionWidth;
 use backend_interface::Backend;
 use clap::Args;
 use nargo::constants::PROVER_INPUT_FILE;
@@ -29,7 +30,21 @@ use crate::errors::CliError;
 use super::NargoConfig;
 
 #[derive(Debug, Clone, Args)]
-pub(crate) struct DapCommand;
+pub(crate) struct DapCommand {
+    /// Override the expression width requested by the backend.
+    #[arg(long, value_parser = parse_expression_width)]
+    expression_width: Option<ExpressionWidth>,
+}
+
+fn parse_expression_width(input: &str) -> Result<ExpressionWidth, std::io::Error> {
+    use std::io::{Error, ErrorKind};
+
+    let width = input
+        .parse::<usize>()
+        .map_err(|err| Error::new(ErrorKind::InvalidInput, err.to_string()))?;
+
+    Ok(ExpressionWidth::from(width))
+}
 
 struct LoadError(&'static str);
 
@@ -54,16 +69,14 @@ fn find_workspace(project_folder: &str, package: Option<&str>) -> Option<Workspa
 }
 
 fn load_and_compile_project(
-    backend: &Backend,
     project_folder: &str,
     package: Option<&str>,
     prover_name: &str,
+    expression_width: ExpressionWidth,
 ) -> Result<(CompiledProgram, WitnessMap), LoadError> {
     let workspace =
         find_workspace(project_folder, package).ok_or(LoadError("Cannot open workspace"))?;
 
-    let expression_width =
-        backend.get_backend_info().map_err(|_| LoadError("Failed to get backend info"))?;
     let package = workspace
         .into_iter()
         .find(|p| p.is_binary())
@@ -100,7 +113,7 @@ fn load_and_compile_project(
 
 fn loop_uninitialized_dap<R: Read, W: Write>(
     mut server: Server<R, W>,
-    backend: &Backend,
+    expression_width: ExpressionWidth,
 ) -> Result<(), ServerError> {
     loop {
         let req = match server.poll_request()? {
@@ -140,7 +153,12 @@ fn loop_uninitialized_dap<R: Read, W: Write>(
                 eprintln!("Package: {}", package.unwrap_or("(default)"));
                 eprintln!("Prover name: {}", prover_name);
 
-                match load_and_compile_project(backend, project_folder, package, prover_name) {
+                match load_and_compile_project(
+                    project_folder,
+                    package,
+                    prover_name,
+                    expression_width,
+                ) {
                     Ok((compiled_program, initial_witness)) => {
                         server.respond(req.ack()?)?;
 
@@ -176,12 +194,15 @@ fn loop_uninitialized_dap<R: Read, W: Write>(
 
 pub(crate) fn run(
     backend: &Backend,
-    _args: DapCommand,
+    args: DapCommand,
     _config: NargoConfig,
 ) -> Result<(), CliError> {
     let output = BufWriter::new(std::io::stdout());
     let input = BufReader::new(std::io::stdin());
     let server = Server::new(input, output);
 
-    loop_uninitialized_dap(server, backend).map_err(CliError::DapError)
+    let expression_width =
+        args.expression_width.unwrap_or_else(|| backend.get_backend_info_or_default());
+
+    loop_uninitialized_dap(server, expression_width).map_err(CliError::DapError)
 }

tooling/nargo_cli/src/cli/debug_cmd.rs

@@ -54,7 +54,10 @@ pub(crate) fn run(
         Some(NOIR_ARTIFACT_VERSION_STRING.to_string()),
     )?;
     let target_dir = &workspace.target_directory_path();
-    let expression_width = backend.get_backend_info()?;
+    let expression_width = args
+        .compile_options
+        .expression_width
+        .unwrap_or_else(|| backend.get_backend_info_or_default());
 
     let mut workspace_file_manager = file_manager_with_stdlib(std::path::Path::new(""));
     insert_all_files_for_workspace_into_file_manager(&workspace, &mut workspace_file_manager);

tooling/nargo_cli/src/cli/execute_cmd.rs

@@ -68,7 +68,10 @@ pub(crate) fn run(
     insert_all_files_for_workspace_into_file_manager(&workspace, &mut workspace_file_manager);
     let parsed_files = parse_all(&workspace_file_manager);
 
-    let expression_width = backend.get_backend_info_or_default();
+    let expression_width = args
+        .compile_options
+        .expression_width
+        .unwrap_or_else(|| backend.get_backend_info_or_default());
     let binary_packages = workspace.into_iter().filter(|package| package.is_binary());
     for package in binary_packages {
         let compilation_result = compile_program(

tooling/nargo_cli/src/cli/info_cmd.rs

@@ -69,7 +69,10 @@ pub(crate) fn run(
     insert_all_files_for_workspace_into_file_manager(&workspace, &mut workspace_file_manager);
     let parsed_files = parse_all(&workspace_file_manager);
 
-    let expression_width = backend.get_backend_info_or_default();
+    let expression_width = args
+        .compile_options
+        .expression_width
+        .unwrap_or_else(|| backend.get_backend_info_or_default());
     let (compiled_programs, compiled_contracts) = compile_workspace(
         &workspace_file_manager,
         &parsed_files,

tooling/nargo_cli/src/cli/prove_cmd.rs

@@ -69,7 +69,10 @@ pub(crate) fn run(
     insert_all_files_for_workspace_into_file_manager(&workspace, &mut workspace_file_manager);
     let parsed_files = parse_all(&workspace_file_manager);
 
-    let expression_width = backend.get_backend_info()?;
+    let expression_width = args
+        .compile_options
+        .expression_width
+        .unwrap_or_else(|| backend.get_backend_info_or_default());
     let binary_packages = workspace.into_iter().filter(|package| package.is_binary());
     for package in binary_packages {
         let compilation_result = compile_program(

tooling/nargo_cli/src/cli/verify_cmd.rs

@@ -54,7 +54,10 @@ pub(crate) fn run(
     insert_all_files_for_workspace_into_file_manager(&workspace, &mut workspace_file_manager);
     let parsed_files = parse_all(&workspace_file_manager);
 
-    let expression_width = backend.get_backend_info()?;
+    let expression_width = args
+        .compile_options
+        .expression_width
+        .unwrap_or_else(|| backend.get_backend_info_or_default());
     let binary_packages = workspace.into_iter().filter(|package| package.is_binary());
     for package in binary_packages {
         let compilation_result = compile_program(