From 0a8dd843b6eaee5f0e6f3d79921caad67d7f1d0d Mon Sep 17 00:00:00 2001
From: Forest Belton <forest@homolo.gy>
Date: Tue, 14 Sep 2021 19:03:10 -0400
Subject: [PATCH] Finish binary operation support and reduce temporaries in IR
 generation

---
 example.gby |  2 +-
 lib/ir.ts   | 57 ++++++++++++++++++++++++++++-------------------------
 2 files changed, 31 insertions(+), 28 deletions(-)

diff --git a/example.gby b/example.gby
index 8d0e5a6..6b14518 100644
--- a/example.gby
+++ b/example.gby
@@ -1,4 +1,4 @@
 u8 x;
 u8 y;
 
-x <- y + 2;
+x <- -y + 3;
diff --git a/lib/ir.ts b/lib/ir.ts
index 4a07c32..5f2c84f 100644
--- a/lib/ir.ts
+++ b/lib/ir.ts
@@ -32,55 +32,58 @@ export const convertIR = (stmts: Array<Stmt>): Array<SSA> => {
 }
 
 export const convertAssignStmt = (state: IRState, stmt: AssignStmt): Array<SSA> => {
-    const dest = stmt.args.name
-    const [source, expr_stmts] = convertExpr(state, stmt.args.expr)
-
-    expr_stmts.push({
-        dest,
-        source,
-    })
-
-    return expr_stmts
+    return convertExpr(state, stmt.args.name, stmt.args.expr)
 }
 
-export const convertExpr = (state: IRState, expr: Expr): [string | number, Array<SSA>] => {
+export const convertExpr = (state: IRState, dest: string, expr: Expr): Array<SSA> => {
+    let expr_stmts = []
+
     if (typeof expr === "number" || typeof expr === "string") {
-        return [expr, []]
+        expr_stmts = [{ dest, source: expr }]
     } else if (expr.type === "unary") {
-        const [source, expr_stmts] = convertExpr(state, expr.arg)
-
-        const name = `temp${state.nextID++}`
-        expr_stmts.push({
-            dest: name,
-            source,
+        const [source, stmts] = getSource(state, expr.arg)
+        stmts.push({
+            dest,
             op: expr.op,
+            source,
         })
 
-        return [name, expr_stmts]
+        expr_stmts = stmts
     } else {
-        const [left_source, left_stmts] = convertExpr(state, expr.left)
-        const [right_source, right_stmts] = convertExpr(state, expr.right)
-        const expr_stmts = [...left_stmts, ...right_stmts]
+        const [left_source, left_stmts] = getSource(state, expr.left)
+        const [right_source, right_stmts] = getSource(state, expr.right)
 
-        const name = `temp${state.nextID++}`
-        expr_stmts.push({
-            dest: name,
+        const stmts = [...left_stmts, ...right_stmts]
+        stmts.push({
+            dest,
             op: expr.op,
             source: left_source,
             source1: right_source,
         })
 
-        return [name, expr_stmts]
+        expr_stmts = stmts
     }
+
+    return expr_stmts
+}
+
+const getSource = (state: IRState, expr: Expr): [string | number, Array<SSA>] => {
+    if (typeof expr === "number" || typeof expr === "string") {
+        return [expr, []]
+    }
+
+    const source = `temp${state.nextID++}`
+    const stmts = convertExpr(state, source, expr)
+    return [source, stmts]
 }
 
 export const prettyPrintIR = (ssa: SSA): string => {
     let output = ""
 
     if ("source1" in ssa) {
-        output = `${ssa.dest} = ${ssa.source} ${ssa.op} ${ssa.source1}`
+        output = `${ssa.dest} = ${ssa.op}(${ssa.source}, ${ssa.source1})`
     } else if ("op" in ssa) {
-        output = `${ssa.dest} = ${ssa.op} ${ssa.source}`
+        output = `${ssa.dest} = ${ssa.op}(${ssa.source})`
     } else {
         output = `${ssa.dest} = ${ssa.source}`
     }