Some cleanups.

src/bin/ngri.rs

@@ -1,8 +1,10 @@
 use codespan_reporting::diagnostic::Diagnostic;
 use codespan_reporting::files::SimpleFiles;
 use codespan_reporting::term::{self, Config};
+use cranelift_jit::JITModule;
+use cranelift_module::ModuleError;
+use ngr::backend::{Backend, BackendError};
 use ngr::ir::Program as IR;
-use ngr::jit::{JITEngine, JITError};
 use ngr::syntax::{Location, ParserError, Statement};
 use pretty::termcolor::{ColorChoice, StandardStream, WriteColor};
 use rustyline::error::ReadlineError;
@@ -11,7 +13,7 @@ use std::collections::HashMap;
 
 pub struct RunLoop<'a> {
     file_database: SimpleFiles<&'a str, String>,
-    jitter: JITEngine,
+    jitter: Backend<JITModule>,
     variable_binding_sites: HashMap<String, Location>,
     gensym_index: usize,
     writer: &'a mut dyn WriteColor,
@@ -24,7 +26,9 @@ enum REPLError {
     #[error("Error parsing statement: {0}")]
     Parser(#[from] ParserError),
     #[error("JIT error: {0}")]
-    JIT(#[from] JITError),
+    JIT(#[from] BackendError),
+    #[error("Internal cranelift error: {0}")]
+    Cranelift(#[from] ModuleError),
     #[error(transparent)]
     Reporting(#[from] codespan_reporting::files::Error),
 }
@@ -34,16 +38,17 @@ impl From<REPLError> for Diagnostic<usize> {
         match value {
             REPLError::Parser(err) => Diagnostic::from(&err),
             REPLError::JIT(err) => Diagnostic::from(err),
+            REPLError::Cranelift(err) => Diagnostic::bug().with_message(format!("{}", err)),
             REPLError::Reporting(err) => Diagnostic::bug().with_message(format!("{}", err)),
         }
     }
 }
 
 impl<'a> RunLoop<'a> {
-    pub fn new(writer: &'a mut dyn WriteColor, config: Config) -> Result<Self, JITError> {
+    pub fn new(writer: &'a mut dyn WriteColor, config: Config) -> Result<Self, BackendError> {
         Ok(RunLoop {
             file_database: SimpleFiles::new(),
-            jitter: JITEngine::new()?,
+            jitter: Backend::jit()?,
             variable_binding_sites: HashMap::new(),
             gensym_index: 1,
             writer,
@@ -83,7 +88,7 @@ impl<'a> RunLoop<'a> {
         // then we won't use this definition until someone tries again.
         if let Statement::Binding(_, ref name, _) = syntax {
             if !self.variable_binding_sites.contains_key(name.as_str()) {
-                self.jitter.define_string(name.clone())?;
+                self.jitter.define_string(name)?;
                 self.jitter.define_variable(name.clone())?;
             }
         };
@@ -104,13 +109,17 @@ impl<'a> RunLoop<'a> {
         }
 
         let ir = IR::from(syntax.simplify(&mut self.gensym_index));
-        let compiled = self.jitter.compile(line_no, ir)?;
-        compiled();
+        let name = format!("line{}", line_no);
+        let function_id = self.jitter.compile_function(&name, ir)?;
+        self.jitter.module.finalize_definitions()?;
+        let compiled_bytes = self.jitter.bytes(function_id);
+        let compiled_function = unsafe { std::mem::transmute::<_, fn() -> ()>(compiled_bytes) };
+        compiled_function();
         Ok(())
     }
 }
 
-fn main() -> Result<(), JITError> {
+fn main() -> Result<(), BackendError> {
     let mut editor = DefaultEditor::new().expect("rustyline works");
     let mut line_no = 0;
     let mut writer = StandardStream::stdout(ColorChoice::Auto);