From 45205f33e508e7990e11411f693961ce37ad7e79 Mon Sep 17 00:00:00 2001
From: SimonFJ20 <simonfromjakobsen@gmail.com>
Date: Wed, 26 Mar 2025 16:21:46 +0100
Subject: [PATCH] compiler: add alloca

---
 backup-compiler/asm_gen.ts      |  6 ++++++
 backup-compiler/lir.ts          |  8 ++++++++
 backup-compiler/lir_gen.ts      | 20 ++++++++++++++++++++
 backup-compiler/lir_optimize.ts |  6 ++++++
 4 files changed, 40 insertions(+)

diff --git a/backup-compiler/asm_gen.ts b/backup-compiler/asm_gen.ts
index 70d30fa..d7947e5 100644
--- a/backup-compiler/asm_gen.ts
+++ b/backup-compiler/asm_gen.ts
@@ -160,6 +160,12 @@ export class AsmGen {
             case "nop":
                 this.writeIns(`nop`);
                 return;
+            case "alloc_param":
+                // should already be handled
+                return;
+            case "alloc_local":
+                // should already be handled
+                return;
             case "mov_int":
                 this.writeIns(`mov ${r(ins.reg)}, ${ins.val}`);
                 return;
diff --git a/backup-compiler/lir.ts b/backup-compiler/lir.ts
index d2021b2..c3bf897 100644
--- a/backup-compiler/lir.ts
+++ b/backup-compiler/lir.ts
@@ -12,6 +12,8 @@ export type Fn = {
     lines: Line[];
     frameSize: number;
     localOffsets: Map<number, number>;
+
+    localRegs: Map<number, Reg>;
 };
 
 export type Line = {
@@ -22,6 +24,8 @@ export type Line = {
 export type Ins =
     | { tag: "error" }
     | { tag: "nop" }
+    | { tag: "alloc_param"; reg: Reg; size: number }
+    | { tag: "alloc_local"; reg: Reg; size: number }
     | { tag: "mov_int"; reg: Reg; val: number }
     | { tag: "mov_string"; reg: Reg; stringId: number }
     | { tag: "mov_fn"; reg: Reg; fn: Fn }
@@ -70,6 +74,10 @@ export class ProgramStringifyer {
                 return "<error>";
             case "nop":
                 return "nop";
+            case "alloc_param":
+                return `alloc_param %${ins.reg}, ${ins.size}`;
+            case "alloc_local":
+                return `alloc_local %${ins.reg}, ${ins.size}`;
             case "mov_int":
                 return `mov_int %${ins.reg}, ${ins.val}`;
             case "mov_string":
diff --git a/backup-compiler/lir_gen.ts b/backup-compiler/lir_gen.ts
index 095e5f0..3b0a2c6 100644
--- a/backup-compiler/lir_gen.ts
+++ b/backup-compiler/lir_gen.ts
@@ -38,6 +38,7 @@ export class LirGen {
                 lines: [],
                 frameSize: 0,
                 localOffsets: new Map(),
+                localRegs: new Map(),
             };
             this.fns.set(id, fn);
             this.stmtFns.set(stmt.id, fn);
@@ -77,6 +78,7 @@ class FnGen {
     private currentLabels: Label[] = [];
 
     private localOffsets = new Map<number, number>();
+    private localRegs = new Map<number, Reg>();
 
     public constructor(
         private fn: Fn,
@@ -96,6 +98,9 @@ class FnGen {
         for (const local of this.fn.mir.paramLocals.values()) {
             this.localOffsets.set(local.id, currentOffset);
             currentOffset -= 8;
+
+            const reg = this.reg();
+            this.pushIns({ tag: "alloc_param", reg, size: 8 });
         }
         // return address
         currentOffset -= 8;
@@ -104,6 +109,13 @@ class FnGen {
         // return value
         this.localOffsets.set(this.fn.mir.returnLocal.id, currentOffset);
         currentOffset -= 8;
+
+        {
+            const reg = this.reg();
+            this.pushIns({ tag: "alloc_local", reg, size: 8 });
+            this.localRegs.set(this.fn.mir.returnLocal.id, reg);
+        }
+
         frameSize += 8;
         for (const local of this.fn.mir.locals) {
             if (this.localOffsets.has(local.id)) {
@@ -113,6 +125,14 @@ class FnGen {
             currentOffset -= 8;
             frameSize += 8;
         }
+        for (const local of this.fn.mir.locals) {
+            if (this.localRegs.has(local.id)) {
+                continue;
+            }
+            const reg = this.reg();
+            this.pushIns({ tag: "alloc_local", reg, size: 8 });
+            this.localRegs.set(local.id, reg);
+        }
 
         if (frameSize % 16 !== 8) {
             frameSize += 8;
diff --git a/backup-compiler/lir_optimize.ts b/backup-compiler/lir_optimize.ts
index da8ecf9..a4f55d6 100644
--- a/backup-compiler/lir_optimize.ts
+++ b/backup-compiler/lir_optimize.ts
@@ -207,6 +207,10 @@ function replaceReg(fn: Fn, cand: Reg, replacement: Reg) {
                 break;
             case "nop":
                 break;
+            case "alloc_param":
+            case "alloc_local":
+                ins.reg = r(ins.reg);
+                break;
             case "mov_int":
             case "mov_string":
             case "mov_fn":
@@ -255,6 +259,8 @@ function pollutesStack(ins: Ins): boolean {
     switch (ins.tag) {
         case "error":
         case "nop":
+        case "alloc_param":
+        case "alloc_local":
         case "mov_int":
         case "mov_string":
         case "mov_fn":