add raw pointers

src/ast.ts

@@ -403,6 +403,10 @@ export type TypeKind<P extends Phase> =
       kind: "tuple";
       elems: Type<P>[];
     }
+  | {
+      kind: "rawptr";
+      inner: Type<P>;
+    }
   | { kind: "never" };
 
 export type Type<P extends Phase> = TypeKind<P> & {
@@ -514,6 +518,11 @@ export type TyStruct = {
   fields: [string, Ty][];
 };
 
+export type TyRawPtr = {
+  kind: "rawptr";
+  inner: TyStruct;
+};
+
 export type TyNever = {
   kind: "never";
 };
@@ -528,6 +537,7 @@ export type Ty =
   | TyFn
   | TyVar
   | TyStruct
+  | TyRawPtr
   | TyNever;
 
 export function tyIsUnit(ty: Ty): ty is TyUnit {
@@ -838,6 +848,12 @@ export function superFoldType<From extends Phase, To extends Phase>(
         span,
       };
     }
+    case "rawptr": {
+      return {
+        ...type,
+        inner: folder.type(type.inner),
+      };
+    }
     case "never": {
       return { ...type, kind: "never" };
     }

src/codegen.ts

@@ -19,6 +19,7 @@ import {
   superFoldExpr,
   superFoldItem,
   varUnreachable,
+  TyRawPtr,
 } from "./ast";
 import { GlobalContext } from "./context";
 import { unreachable } from "./error";
@@ -443,8 +444,10 @@ function tryLowerLValue(
   instrs: wasm.Instr[],
   expr: Expr<Typecked>,
 ): LValue | undefined {
-  const fieldParts = (ty: TyStruct, fieldIdx: number): MemoryLayoutPart[] =>
-    unwrap(layoutOfStruct(ty).fields[fieldIdx]).types;
+  const fieldParts = (
+    ty: TyStruct | TyRawPtr,
+    fieldIdx: number,
+  ): MemoryLayoutPart[] => unwrap(layoutOfStruct(ty).fields[fieldIdx]).types;
 
   switch (expr.kind) {
     case "ident":
@@ -489,7 +492,8 @@ function tryLowerLValue(
           // _potentially_ a localTupleField
           todo("tuple access");
         }
-        case "struct": {
+        case "struct":
+        case "rawptr": {
           // Codegen the base, this leaves us with the base pointer on the stack.
           // Do not increment the refcount for an lvalue base.
           lowerExpr(fcx, instrs, expr.lhs, true);
@@ -908,7 +912,8 @@ function lowerExpr(
 
           break;
         }
-        case "struct": {
+        case "struct":
+        case "rawptr": {
           const ty = expr.lhs.ty;
           const layout = layoutOfStruct(ty);
           const field = layout.fields[expr.field.fieldIdx!];
@@ -1027,7 +1032,7 @@ function lowerExpr(
     }
     case "structLiteral": {
       if (expr.ty.kind !== "struct") {
-        throw new Error("struct literal must have struct type");
+        unreachable("struct literal must have struct type");
       }
       const layout = layoutOfStruct(expr.ty);
 
@@ -1236,6 +1241,7 @@ function argRetAbi(param: Ty): ArgRetAbi {
     case "tuple":
       return param.elems.flatMap(argRetAbi);
     case "struct":
+    case "rawptr":
       return ["i32"];
     case "never":
       return [];
@@ -1290,6 +1296,7 @@ function wasmTypeForBody(ty: Ty): wasm.ValType[] {
     case "fn":
       todo("fn types");
     case "struct":
+    case "rawptr":
       return ["i32"];
     case "never":
       return [];
@@ -1313,7 +1320,8 @@ function sizeOfValtype(type: wasm.ValType): number {
   }
 }
 
-export function layoutOfStruct(ty: TyStruct): StructLayout {
+export function layoutOfStruct(ty_: TyStruct | TyRawPtr): StructLayout {
+  const ty = ty_.kind === "struct" ? ty_ : ty_.inner;
   const fieldWasmTys = ty.fields.map(([, field]) => wasmTypeForBody(field));
 
   // TODO: Use the max alignment instead.

src/index.ts

@@ -14,28 +14,16 @@ import { loadCrate } from "./loader";
 
 const INPUT = `
 type A = struct { a: Int };
-type Complex = struct {
-  a: Int,
-  b: (Int, A),
-};
 
 function main() = (
   let a = A { a: 0 };
-  // let b = 0;
-  let c = Complex { a: 0, b: (0, a) };
-
-  write(a);
-  std.printlnInt(a.a);
-
-  // ptr = c + offset(b) + offset(1)
-  // a = load(ptr)
-  // store(a + offset(a), 1)
-  // c.b.1.a = 1;
+  rawr(___transmute(a));
+  std.printInt(a.a);
 );
 
-function write(a: A) = a.a = 1;
-
-function ret(): A = A { a: 0 };
+function rawr(a: *A) = (
+  a.a = 1;
+);
 `;
 
 function main() {

src/parser.ts

@@ -650,6 +650,12 @@ function parseType(t: State): [State, Type<Parsed>] {
 
       return [t, { kind: "tuple", elems: [head, ...tail], span }];
     }
+    case "*": {
+      let inner;
+      [t, inner] = parseType(t);
+
+      return [t, { kind: "rawptr", inner, span }];
+    }
     default: {
       throw new CompilerError(
         `unexpected token: \`${tok.kind}\`, expected type`,

src/printer.ts

@@ -214,6 +214,8 @@ function printType(type: Type<AnyPhase>): string {
       return `[${printType(type.elem)}]`;
     case "tuple":
       return `(${type.elems.map(printType).join(", ")})`;
+    case "rawptr":
+      return `*${printType(type.inner)}`;
     case "never":
       return "!";
   }
@@ -266,6 +268,9 @@ export function printTy(ty: Ty): string {
     case "struct": {
       return ty._name;
     }
+    case "rawptr": {
+      return `*${printTy(ty.inner)}`;
+    }
     case "never": {
       return "!";
     }

src/typeck.ts

@@ -131,6 +131,17 @@ function lowerAstTy(cx: TypeckCtx, type: Type<Resolved>): Ty {
         elems: type.elems.map((type) => lowerAstTy(cx, type)),
       };
     }
+    case "rawptr": {
+      const inner = lowerAstTy(cx, type.inner);
+      if (inner.kind !== "struct") {
+        throw new CompilerError(
+          "raw pointers must point to structs",
+          type.span,
+        );
+      }
+
+      return { kind: "rawptr", inner };
+    }
     case "never": {
       return TY_NEVER;
     }
@@ -778,11 +789,12 @@ export function checkBody(
               }
               break;
             }
-            case "struct": {
+            case "struct":
+            case "rawptr": {
+              const fields =
+                lhs.ty.kind === "struct" ? lhs.ty.fields : lhs.ty.inner.fields;
               if (typeof field.value === "string") {
-                const idx = lhs.ty.fields.findIndex(
-                  ([name]) => name === field.value,
-                );
+                const idx = fields.findIndex(([name]) => name === field.value);
                 if (idx === -1) {
                   throw new CompilerError(
                     `field \`${field.value}\` does not exist on ${printTy(
@@ -792,7 +804,7 @@ export function checkBody(
                   );
                 }
 
-                ty = lhs.ty.fields[idx][1];
+                ty = fields[idx][1];
                 fieldIdx = idx;
               } else {
                 throw new CompilerError(
@@ -962,7 +974,10 @@ function checkLValue(expr: Expr<Typecked>) {
       checkLValue(expr.lhs);
       break;
     default:
-      throw new CompilerError("invalid left-hand side of assignment", expr.span);
+      throw new CompilerError(
+        "invalid left-hand side of assignment",
+        expr.span,
+      );
   }
 }
 

ui-tests/raw_ptr.nil

@@ -0,0 +1,13 @@
+//@check-pass
+
+type A = struct { a: Int };
+
+function main() = (
+  let a = A { a: 0 };
+  rawr(___transmute(a));
+  std.printInt(a.a);
+);
+
+function rawr(a: *A) = (
+  a.a = 1;
+);

ui-tests/struct_fields.nil

@@ -0,0 +1,21 @@
+//@check-pass
+
+type A = struct { a: Int };
+type Complex = struct {
+  a: Int,
+  b: (Int, A),
+};
+
+function main() = (
+  let a = A { a: 0 };
+  // let b = 0;
+  // let c = Complex { a: 0, b: (0, a) };
+
+  write(a);
+
+  // c.b.1.a = 1; TODO
+);
+
+function write(a: A) = a.a = 1;
+
+function ret(): A = A { a: 0 };