stage2 AArch64: implement is_err/is_non_err for simple error unions

1 files changed, 73 insertions, 20 deletions

diff --git a/src/arch/aarch64/CodeGen.zig b/src/arch/aarch64/CodeGen.zig
index 79fa38e275..fd9211d919 100644
--- a/src/arch/aarch64/CodeGen.zig
+++ b/src/arch/aarch64/CodeGen.zig
@@ -1104,7 +1104,13 @@ fn airUnwrapErrErr(self: *Self, inst: Air.Inst.Index) !void {
 
 fn airUnwrapErrPayload(self: *Self, inst: Air.Inst.Index) !void {
     const ty_op = self.air.instructions.items(.data)[inst].ty_op;
-    const result: MCValue = if (self.liveness.isUnused(inst)) .dead else return self.fail("TODO implement unwrap error union payload for {}", .{self.target.cpu.arch});
+    const result: MCValue = if (self.liveness.isUnused(inst)) .dead else result: {
+        const error_union_ty = self.air.typeOf(ty_op.operand);
+        const payload_ty = error_union_ty.errorUnionPayload();
+        if (!payload_ty.hasRuntimeBits()) break :result MCValue.none;
+
+        return self.fail("TODO implement unwrap error union payload for non-empty payloads", .{});
+    };
     return self.finishAir(inst, result, .{ ty_op.operand, .none, .none });
 }
 
@@ -2008,18 +2014,52 @@ fn isNonNull(self: *Self, operand: MCValue) !MCValue {
     return self.fail("TODO call isNull and invert the result", .{});
 }
 
-fn isErr(self: *Self, operand: MCValue) !MCValue {
+fn isErr(self: *Self, ty: Type, operand: MCValue) !MCValue {
     _ = operand;
-    // Here you can specialize this instruction if it makes sense to, otherwise the default
-    // will call isNonNull and invert the result.
-    return self.fail("TODO call isNonErr and invert the result", .{});
+
+    const error_type = ty.errorUnionSet();
+    const payload_type = ty.errorUnionPayload();
+
+    if (!error_type.hasRuntimeBits()) {
+        return MCValue{ .immediate = 0 }; // always false
+    } else if (!payload_type.hasRuntimeBits()) {
+        if (error_type.abiSize(self.target.*) <= 8) {
+            const reg_mcv: MCValue = switch (operand) {
+                .register => operand,
+                else => .{ .register = try self.copyToTmpRegister(error_type, operand) },
+            };
+
+            _ = try self.addInst(.{
+                .tag = .cmp_immediate,
+                .data = .{ .rr_imm12_sh = .{
+                    .rd = .xzr,
+                    .rn = reg_mcv.register,
+                    .imm12 = 0,
+                } },
+            });
+
+            return MCValue{ .compare_flags_unsigned = .gt };
+        } else {
+            return self.fail("TODO isErr for errors with size > 8", .{});
+        }
+    } else {
+        return self.fail("TODO isErr for non-empty payloads", .{});
+    }
 }
 
-fn isNonErr(self: *Self, operand: MCValue) !MCValue {
-    _ = operand;
-    // Here you can specialize this instruction if it makes sense to, otherwise the default
-    // will call isNull and invert the result.
-    return self.fail("TODO call isErr and invert the result", .{});
+fn isNonErr(self: *Self, ty: Type, operand: MCValue) !MCValue {
+    const is_err_result = try self.isErr(ty, operand);
+    switch (is_err_result) {
+        .compare_flags_unsigned => |op| {
+            assert(op == .gt);
+            return MCValue{ .compare_flags_unsigned = .lte };
+        },
+        .immediate => |imm| {
+            assert(imm == 0);
+            return MCValue{ .immediate = 1 };
+        },
+        else => unreachable,
+    }
 }
 
 fn airIsNull(self: *Self, inst: Air.Inst.Index) !void {
@@ -2080,7 +2120,8 @@ fn airIsErr(self: *Self, inst: Air.Inst.Index) !void {
     const un_op = self.air.instructions.items(.data)[inst].un_op;
     const result: MCValue = if (self.liveness.isUnused(inst)) .dead else result: {
         const operand = try self.resolveInst(un_op);
-        break :result try self.isErr(operand);
+        const ty = self.air.typeOf(un_op);
+        break :result try self.isErr(ty, operand);
     };
     return self.finishAir(inst, result, .{ un_op, .none, .none });
 }
@@ -2089,6 +2130,7 @@ fn airIsErrPtr(self: *Self, inst: Air.Inst.Index) !void {
     const un_op = self.air.instructions.items(.data)[inst].un_op;
     const result: MCValue = if (self.liveness.isUnused(inst)) .dead else result: {
         const operand_ptr = try self.resolveInst(un_op);
+        const ptr_ty = self.air.typeOf(un_op);
         const operand: MCValue = blk: {
             if (self.reuseOperand(inst, un_op, 0, operand_ptr)) {
                 // The MCValue that holds the pointer can be re-used as the value.
@@ -2098,7 +2140,7 @@ fn airIsErrPtr(self: *Self, inst: Air.Inst.Index) !void {
             }
         };
         try self.load(operand, operand_ptr, self.air.typeOf(un_op));
-        break :result try self.isErr(operand);
+        break :result try self.isErr(ptr_ty.elemType(), operand);
     };
     return self.finishAir(inst, result, .{ un_op, .none, .none });
 }
@@ -2107,7 +2149,8 @@ fn airIsNonErr(self: *Self, inst: Air.Inst.Index) !void {
     const un_op = self.air.instructions.items(.data)[inst].un_op;
     const result: MCValue = if (self.liveness.isUnused(inst)) .dead else result: {
         const operand = try self.resolveInst(un_op);
-        break :result try self.isNonErr(operand);
+        const ty = self.air.typeOf(un_op);
+        break :result try self.isNonErr(ty, operand);
     };
     return self.finishAir(inst, result, .{ un_op, .none, .none });
 }
@@ -2116,6 +2159,7 @@ fn airIsNonErrPtr(self: *Self, inst: Air.Inst.Index) !void {
     const un_op = self.air.instructions.items(.data)[inst].un_op;
     const result: MCValue = if (self.liveness.isUnused(inst)) .dead else result: {
         const operand_ptr = try self.resolveInst(un_op);
+        const ptr_ty = self.air.typeOf(un_op);
         const operand: MCValue = blk: {
             if (self.reuseOperand(inst, un_op, 0, operand_ptr)) {
                 // The MCValue that holds the pointer can be re-used as the value.
@@ -2125,7 +2169,7 @@ fn airIsNonErrPtr(self: *Self, inst: Air.Inst.Index) !void {
             }
         };
         try self.load(operand, operand_ptr, self.air.typeOf(un_op));
-        break :result try self.isNonErr(operand);
+        break :result try self.isNonErr(ptr_ty.elemType(), operand);
     };
     return self.finishAir(inst, result, .{ un_op, .none, .none });
 }
@@ -2864,14 +2908,23 @@ fn genTypedValue(self: *Self, typed_value: TypedValue) InnerError!MCValue {
         .ErrorUnion => {
             const error_type = typed_value.ty.errorUnionSet();
             const payload_type = typed_value.ty.errorUnionPayload();
-            const sub_val = typed_value.val.castTag(.eu_payload).?.data;
 
-            if (!payload_type.hasRuntimeBits()) {
-                // We use the error type directly as the type.
-                return self.genTypedValue(.{ .ty = error_type, .val = sub_val });
-            }
+            if (typed_value.val.castTag(.eu_payload)) |pl| {
+                if (!payload_type.hasRuntimeBits()) {
+                    // We use the error type directly as the type.
+                    return MCValue{ .immediate = 0 };
+                }
 
-            return self.fail("TODO implement error union const of type '{}'", .{typed_value.ty});
+                _ = pl;
+                return self.fail("TODO implement error union const of type '{}' (non-error)", .{typed_value.ty});
+            } else {
+                if (!payload_type.hasRuntimeBits()) {
+                    // We use the error type directly as the type.
+                    return self.genTypedValue(.{ .ty = error_type, .val = typed_value.val });
+                }
+
+                return self.fail("TODO implement error union const of type '{}' (error)", .{typed_value.ty});
+            }
         },
         else => return self.fail("TODO implement const of type '{}'", .{typed_value.ty}),
     }