SÅ HÄR HÅLLER DOM På

Author: bfredl

wasm_anon/src/Interpreter.zig

@@ -659,27 +659,50 @@ fn run_vm(stack: *Interpreter, in: *Instance, r: *Reader) !void {
     }
 }
 
-pub fn eval_constant_expr(r: *Reader, typ: defs.ValType, preglobals: []const StackValue) !StackValue {
+pub fn eval_constant_expr(r: *Reader, typ: defs.ValType, preglobals: []const StackValue, gpa: std.mem.Allocator) !StackValue {
     // shortcut: `expr` is just "i??.const VAL end"
-    const eval = try r.readByte();
-    const init_typ: defs.OpCode = @enumFromInt(eval);
     _ = typ;
-    const val: StackValue = val: switch (init_typ) {
-        .i32_const => .{ .i32 = try r.readLeb(i32) },
-        .i64_const => .{ .i64 = try r.readLeb(i64) },
-        .f32_const => .{ .f32 = try r.readf(f32) },
-        .f64_const => .{ .f64 = try r.readf(f64) },
-        .ref_null => {
+
+    var stack: std.ArrayList(StackValue) = .empty;
+
+    while (true) {
+        const eval = try r.readByte();
+        const init_typ: defs.OpCode = @enumFromInt(eval);
+        const val: StackValue = val: switch (init_typ) {
+            .i32_const => .{ .i32 = try r.readLeb(i32) },
+            .i64_const => .{ .i64 = try r.readLeb(i64) },
+            .f32_const => .{ .f32 = try r.readf(f32) },
+            .f64_const => .{ .f64 = try r.readf(f64) },
+            .ref_null => {
+                _ = try r.readByte();
+                break :val .{ .ref = 0 };
+            },
+            .global_get => {
+                const idx = try r.readu();
+                if (idx >= preglobals.len) return error.InvalidFormat;
+                break :val preglobals[idx].indir.*;
+            },
+            .i32_add, .i32_sub, .i32_mul, .i64_add, .i64_sub, .i64_mul => {
+                const rhs = stack.pop() orelse return error.InvalidFormat;
+                const lhs = stack.pop() orelse return error.InvalidFormat;
+                break :val switch (init_typ) {
+                    .i32_add => .{ .i32 = lhs.i32 + rhs.i32 },
+                    .i32_sub => .{ .i32 = lhs.i32 - rhs.i32 },
+                    .i32_mul => .{ .i32 = lhs.i32 * rhs.i32 },
+                    .i64_add => .{ .i64 = lhs.i64 + rhs.i64 },
+                    .i64_sub => .{ .i64 = lhs.i64 - rhs.i64 },
+                    .i64_mul => .{ .i64 = lhs.i64 * rhs.i64 },
+                    else => unreachable,
+                };
+            },
+            else => return error.InvalidFormat,
+        };
+        if (r.peekByte() == 0x0b) {
             _ = try r.readByte();
-            break :val .{ .ref = 0 };
-        },
-        .global_get => {
-            const idx = try r.readu();
-            if (idx >= preglobals.len) return error.InvalidFormat;
-            break :val preglobals[idx].indir.*;
-        },
-        else => return error.InvalidFormat,
-    };
-    if (try r.readByte() != 0x0b) return error.InvalidFormat;
-    return val;
+            if (stack.items.len > 0) return error.InvalidFormat;
+            return val;
+        } else {
+            try stack.append(gpa, val);
+        }
+    }
 }

wasm_anon/src/Module.zig

@@ -324,7 +324,7 @@ pub fn init_data(self: *Module, mem: []u8, preglobals: []const defs.StackValue)
         const memidx = if (typ == 0) 0 else try r.readu();
         if (memidx > 0) return error.NotImplemented;
 
-        const offset: usize = @intCast((try Interpreter.eval_constant_expr(&r, .i32, preglobals)).i32);
+        const offset: usize = @intCast((try Interpreter.eval_constant_expr(&r, .i32, preglobals, self.allocator)).i32);
         const lenna = try r.readu();
         dbg("offsetta: {}, len: {}\n", .{ offset, lenna });
 
@@ -398,7 +398,7 @@ pub fn init_imports(self: *Module, in: *Instance, imports: ?*ImportTable) !void
         const typ: defs.ValType = @enumFromInt(try r.readByte());
         _ = try r.readByte(); // WHO FUCKING CARES IF IT IS MUTABLE OR NOT
 
-        in.globals_maybe_indir[self.n_globals_import + i] = try Interpreter.eval_constant_expr(&r, typ, in.preglobals());
+        in.globals_maybe_indir[self.n_globals_import + i] = try Interpreter.eval_constant_expr(&r, typ, in.preglobals(), self.allocator);
     }
 }
 
@@ -448,7 +448,7 @@ pub fn element_section(self: *Module, in: *Instance) !void {
     for (0..len) |_| {
         const kinda = try r.readu();
         if (kinda == 0) {
-            const offset: usize = @intCast((try Interpreter.eval_constant_expr(&r, .i32, in.preglobals())).i32);
+            const offset: usize = @intCast((try Interpreter.eval_constant_expr(&r, .i32, in.preglobals(), self.allocator)).i32);
             const elen = try r.readu();
             if (offset + len > in.funcref_table.len) {
                 return error.InvalidFormat;