Functions

.editorconfig

@@ -0,0 +1,2 @@
+[*.rs]
+max_line_length = 80

src/ast/mod.rs

@@ -64,10 +64,13 @@ pub enum Op {
 }
 
 impl Op {
-  pub fn check_types(&self, left_ty: &Type, right_ty: &Type) -> bool {
+  pub fn check_types(&self, left_ty: &Type, right_ty: &Type) -> Option<Type> {
     // TODO: since only binops work on integers right now, just check that the two sides are both
     // integers. this will have to change once && gets added.
-    matches!(left_ty, Type::Int) && matches!(right_ty, Type::Int)
+    match (left_ty, right_ty) {
+      (Type::Int, Type::Int) => Some(Type::Int),
+      _ => None,
+    }
   }
 }
 

src/codegen/llvm_ir/expr.rs

@@ -2,14 +2,14 @@ use std::io::Write;
 
 use anyhow::Result;
 
-use crate::ast::{Expr, ExprKind, Stmt, Type};
+use crate::ast::{Expr, ExprKind, Op, Type};
 
 use super::{type_to_llvm, LlvmIrCodegen};
 
 pub struct ExprLlvm<'a>(String, &'a Expr<Type>);
 
 impl<'a> ExprLlvm<'a> {
-  pub fn name(&self) -> &str {
+  pub fn as_str(&self) -> &str {
     &self.0
   }
 }
@@ -20,27 +20,80 @@ impl<W: Write> LlvmIrCodegen<W> {
     expr: &'a Expr<Type>,
   ) -> Result<ExprLlvm<'a>> {
     let ty_str = type_to_llvm(&expr.ty);
-    let mut expr_id = self.gensym("expr");
+    let mut expr_ref = self.gensym(Some("%"), "expr");
 
     match &expr.kind {
       ExprKind::Int(n) => {
-        writeln!(self.writer, "%{} = alloca {}", expr_id, ty_str)?;
-        writeln!(
-          self.writer,
-          "store {} {}, {}* %{}",
-          ty_str, n, ty_str, expr_id
-        )?;
+        expr_ref = format!("{}", n);
+        // writeln!(self.writer, "%{} = alloca {}", expr_id, ty_str)?;
+        // writeln!(
+        //   self.writer,
+        //   "store {} {}, {}* %{}",
+        //   ty_str, n, ty_str, expr_id
+        // )?;
       }
       ExprKind::Var(name) => match self.var_env.lookup(name) {
         Some((_, name)) => {
-          expr_id = name.clone();
+          expr_ref = name.clone();
         }
         None => bail!("Unbound name {name:?}"),
       },
-      ExprKind::BinOp(_, _, _) => todo!(),
-      ExprKind::Call(_, _) => todo!(),
+      ExprKind::BinOp(left, op, right) => {
+        let result_ty = match op.check_types(&left.ty, &right.ty) {
+          Some(v) => type_to_llvm(&v),
+          None => bail!("Invalid types on operation."),
+        };
+
+        let left = self.convert_expr(left)?;
+
+        let right = self.convert_expr(right)?;
+
+        match op {
+          Op::LessThan => todo!(),
+          Op::GreaterThan => todo!(),
+          Op::Plus => writeln!(
+            self.writer,
+            "{} = add {} {}, {}",
+            expr_ref,
+            result_ty,
+            left.as_str(),
+            right.as_str(),
+          )?,
+        }
+      }
+      ExprKind::Call(func, args) => match self.var_env.lookup(func) {
+        Some((Type::Func(func_args_ty, func_ret_ty), func_name)) => {
+          // Clone these so we aren't depending on a reference
+          let func_args_ty = func_args_ty.clone();
+          let func_ret_ty = func_ret_ty.clone();
+          let func_name = func_name.to_owned();
+
+          let mut args_str = Vec::new();
+          for (call_arg, expected_ty) in args.iter().zip(func_args_ty.iter()) {
+            let call_ty = &call_arg.ty;
+            if call_ty != expected_ty {
+              bail!("Type error: expected {expected_ty:?}, got {call_ty:?}");
+            }
+
+            let expr = self.convert_expr(&call_arg)?;
+            let call_ty_str = type_to_llvm(&call_ty);
+            args_str.push(format!("{} {}", call_ty_str, expr.as_str()));
+          }
+
+          let ret_ty_str = type_to_llvm(&func_ret_ty);
+          writeln!(
+            self.writer,
+            "{} = call {} {} ({})",
+            expr_ref,
+            ret_ty_str,
+            func_name,
+            args_str.join(", ")
+          )?;
+        }
+        _ => bail!("No function with name {func:?}"),
+      },
     }
 
-    Ok(ExprLlvm(expr_id, expr))
+    Ok(ExprLlvm(expr_ref, expr))
   }
 }

src/codegen/llvm_ir/mod.rs

@@ -27,10 +27,19 @@ impl<W> LlvmIrCodegen<W> {
     }
   }
 
-  pub fn gensym(&mut self, name: impl AsRef<str>) -> String {
+  pub fn gensym(
+    &mut self,
+    prefix: Option<&str>,
+    name: impl AsRef<str>,
+  ) -> String {
     let ctr = self.ctr;
     self.ctr += 1;
-    format!("{}.{}", name.as_ref(), ctr)
+    format!(
+      "{}{}.{}",
+      prefix.map(|s| s.as_ref()).unwrap_or(""),
+      name.as_ref(),
+      ctr
+    )
   }
 }
 
@@ -45,30 +54,67 @@ fn type_to_llvm(ty: &Type) -> String {
 
 impl<W: Write> CodegenBackend for LlvmIrCodegen<W> {
   fn convert(&mut self, program: Vec<Decl<Type>>) -> Result<()> {
+    // First, create a global environment and add all functions, so they can be
+    // called within other functions
+    //
+    // This is in a separate loop so there's no dependency on function order
+    self.var_env = LayeredEnv::new();
+    for func in program.iter().filter_map(|decl| match decl {
+      Decl::Func(v) => Some(v),
+      _ => None,
+    }) {
+      let func_name = match func.name.as_str() {
+        "main" => String::from("@main"),
+        _ => self.gensym(Some("@"), format!("func.{}", func.name)),
+      };
+      let value = (func.ty.clone(), func_name);
+      self.var_env.insert(func.name.clone(), value);
+    }
+
     // Convert all functions
     for func in program.iter().filter_map(|decl| match decl {
       Decl::Func(v) => Some(v),
       _ => None,
     }) {
-      // Write the function header
-      println!("Func type: {:?}", func.ty);
-      let (func_args_ty, ret_ty) = match &func.ty {
+      let (_, ret_ty) = match &func.ty {
         Type::Func(args, ret) => (args, ret),
         _ => unreachable!(""),
       };
+      let (_, func_name) =
+        self.var_env.lookup(&func.name).expect("Just inserted.");
+      let func_name = func_name.to_owned();
 
+      // Set the global environment by adding the arguments
+      let mut args_str = Vec::new();
+      self.var_env.push();
+      for arg in func.args.iter() {
+        let arg_name = self.gensym(Some("%"), &arg.name);
+        let arg_ty_str = type_to_llvm(&arg.ty);
+        args_str.push(format!("{} {}", arg_ty_str, arg_name));
+        self
+          .var_env
+          .insert(arg.name.clone(), (arg.ty.clone(), arg_name));
+      }
+
+      // Write the function header
       writeln!(
         self.writer,
-        "define {} @{} () {{",
+        "define {} {} ({}) {{",
         type_to_llvm(ret_ty),
-        func.name
+        func_name,
+        args_str.join(", "),
       )?;
-      let entry_block_name = self.gensym("entry");
+
+      // Write the first block
+      let entry_block_name = self.gensym(None, "entry");
       writeln!(self.writer, "{}:", entry_block_name)?;
 
+      self.var_env.push();
       self.convert_stmts(&func.stmts)?;
+      self.var_env.pop();
 
       writeln!(self.writer, "}}")?;
+      self.var_env.pop();
     }
 
     Ok(())

src/codegen/llvm_ir/stmts.rs

@@ -18,25 +18,14 @@ impl<W: Write> LlvmIrCodegen<W> {
         Stmt::Let(name, _, expr) => {
           let ty = expr.ty.clone();
           let expr = self.convert_expr(&expr)?;
-          let new_name = expr.name().to_owned();
-
-          // TODO:
+          let new_name = expr.as_str().to_owned();
           self.var_env.insert(name.clone(), (ty, new_name));
         }
         Stmt::Return(expr) => match expr {
           Some(ret_val) => {
             let ret_ty = type_to_llvm(&ret_val.ty);
             let ret_val = self.convert_expr(ret_val)?;
-            let ret_name = self.gensym("ret");
-            writeln!(
-              self.writer,
-              "%{} = load {}, {}* %{}",
-              ret_name,
-              ret_ty,
-              ret_ty,
-              ret_val.name()
-            )?;
-            writeln!(self.writer, "ret {} %{}", ret_ty, ret_name)?;
+            writeln!(self.writer, "ret {} {}", ret_ty, ret_val.as_str())?;
           }
           None => writeln!(self.writer, "ret void")?,
         },

src/utils.rs

@@ -1,36 +1,34 @@
 use std::collections::HashMap;
 use std::hash::Hash;
 
+#[derive(Debug)]
 pub struct LayeredEnv<K, V> {
-  parent: Option<Box<LayeredEnv<K, V>>>,
-  inner_map: HashMap<K, V>,
+  inner: Option<InnerEnv<K, V>>,
 }
 
-impl<K: Hash + Eq, V> LayeredEnv<K, V> {
-  pub fn new() -> Self {
-    LayeredEnv {
+#[derive(Debug)]
+struct InnerEnv<K, V> {
+  parent: Option<Box<InnerEnv<K, V>>>,
+  map: HashMap<K, V>,
+}
+
+impl<K: Hash + Eq, V> InnerEnv<K, V> {
+  fn new() -> Self {
+    InnerEnv {
       parent: None,
-      inner_map: HashMap::new(),
+      map: HashMap::new(),
     }
   }
 
-  pub fn insert(&mut self, key: K, value: V) {
-    self.inner_map.insert(key, value);
-  }
-
-  pub fn push(self) -> LayeredEnv<K, V> {
-    LayeredEnv {
-      parent: Some(Box::new(self)),
-      inner_map: HashMap::new(),
+  fn with_parent(parent: InnerEnv<K, V>) -> Self {
+    InnerEnv {
+      parent: Some(Box::new(parent)),
+      map: HashMap::new(),
     }
   }
 
-  pub fn pop(self) -> LayeredEnv<K, V> {
-    *self.parent.unwrap()
-  }
-
-  pub fn lookup(&self, key: &K) -> Option<&V> {
-    match self.inner_map.get(key) {
+  fn lookup(&self, key: &K) -> Option<&V> {
+    match self.map.get(key) {
       Some(v) => Some(v),
       None => match self.parent.as_ref() {
         Some(p) => p.lookup(key),
@@ -39,3 +37,29 @@ impl<K: Hash + Eq, V> LayeredEnv<K, V> {
     }
   }
 }
+
+impl<K: Hash + Eq, V> LayeredEnv<K, V> {
+  pub fn new() -> Self {
+    LayeredEnv {
+      inner: Some(InnerEnv::new()),
+    }
+  }
+
+  pub fn insert(&mut self, key: K, value: V) {
+    self.inner.as_mut().unwrap().map.insert(key, value);
+  }
+
+  pub fn push(&mut self) {
+    let inner = self.inner.take().unwrap();
+    self.inner = Some(InnerEnv::with_parent(inner));
+  }
+
+  pub fn pop(&mut self) {
+    let inner = self.inner.take().unwrap();
+    self.inner = Some(*inner.parent.unwrap());
+  }
+
+  pub fn lookup(&self, key: &K) -> Option<&V> {
+    self.inner.as_ref().unwrap().lookup(key)
+  }
+}