py: Make viper codegen raise proper exception (ViperTypeError) on error.

This fixes a long standing problem that viper code generation gave terrible error messages, and actually no errors on pyboard where assertions are disabled. Now all compile-time errors are raised as proper Python exceptions, and are of type ViperTypeError. Addresses issue micropython#940.

Author: dpgeorge

py/compile.c

@@ -3764,22 +3764,22 @@ mp_obj_t mp_compile(mp_parse_node_t pn, qstr source_file, uint emit_opt, bool is
  case MP_EMIT_OPT_VIPER:
 #if MICROPY_EMIT_X64
  if (emit_native == NULL) {
- emit_native = emit_native_x64_new(max_num_labels);
+ emit_native = emit_native_x64_new(&comp->compile_error, max_num_labels);
  }
  comp->emit_method_table = &emit_native_x64_method_table;
 #elif MICROPY_EMIT_X86
  if (emit_native == NULL) {
- emit_native = emit_native_x86_new(max_num_labels);
+ emit_native = emit_native_x86_new(&comp->compile_error, max_num_labels);
  }
  comp->emit_method_table = &emit_native_x86_method_table;
 #elif MICROPY_EMIT_THUMB
  if (emit_native == NULL) {
- emit_native = emit_native_thumb_new(max_num_labels);
+ emit_native = emit_native_thumb_new(&comp->compile_error, max_num_labels);
  }
  comp->emit_method_table = &emit_native_thumb_method_table;
 #elif MICROPY_EMIT_ARM
  if (emit_native == NULL) {
- emit_native = emit_native_arm_new(max_num_labels);
+ emit_native = emit_native_arm_new(&comp->compile_error, max_num_labels);
  }
  comp->emit_method_table = &emit_native_arm_method_table;
 #endif

py/emit.h

@@ -172,10 +172,10 @@ extern const mp_emit_method_table_id_ops_t mp_emit_bc_method_table_delete_id_ops
 
 emit_t *emit_cpython_new(void);
 emit_t *emit_bc_new(void);
-emit_t *emit_native_x64_new(mp_uint_t max_num_labels);
-emit_t *emit_native_x86_new(mp_uint_t max_num_labels);
-emit_t *emit_native_thumb_new(mp_uint_t max_num_labels);
-emit_t *emit_native_arm_new(mp_uint_t max_num_labels);
+emit_t *emit_native_x64_new(mp_obj_t *error_slot, mp_uint_t max_num_labels);
+emit_t *emit_native_x86_new(mp_obj_t *error_slot, mp_uint_t max_num_labels);
+emit_t *emit_native_thumb_new(mp_obj_t *error_slot, mp_uint_t max_num_labels);
+emit_t *emit_native_arm_new(mp_obj_t *error_slot, mp_uint_t max_num_labels);
 
 void emit_cpython_set_max_num_labels(emit_t* emit, mp_uint_t max_num_labels);
 void emit_bc_set_max_num_labels(emit_t* emit, mp_uint_t max_num_labels);

py/emitnative.c

@@ -482,6 +482,10 @@ STATIC byte mp_f_n_args[MP_F_NUMBER_OF] = {
 
 #endif
 
+#define EMIT_NATIVE_VIPER_TYPE_ERROR(emit, ...) do { \
+ *emit->error_slot = mp_obj_new_exception_msg_varg(&mp_type_ViperTypeError, __VA_ARGS__); \
+ } while (0)
+
 typedef enum {
  STACK_VALUE,
  STACK_REG,
@@ -505,6 +509,19 @@ typedef enum {
  VTYPE_BUILTIN_CAST = 0x60 | MP_NATIVE_TYPE_OBJ,
 } vtype_kind_t;
 
+STATIC qstr vtype_to_qstr(vtype_kind_t vtype) {
+ switch (vtype) {
+ case VTYPE_PYOBJ: return MP_QSTR_object;
+ case VTYPE_BOOL: return MP_QSTR_bool;
+ case VTYPE_INT: return MP_QSTR_int;
+ case VTYPE_UINT: return MP_QSTR_uint;
+ case VTYPE_PTR: return MP_QSTR_ptr;
+ case VTYPE_PTR8: return MP_QSTR_ptr8;
+ case VTYPE_PTR16: return MP_QSTR_ptr16;
+ case VTYPE_PTR_NONE: default: return MP_QSTR_None;
+ }
+}
+
 typedef struct _stack_info_t {
  vtype_kind_t vtype;
  stack_info_kind_t kind;
@@ -515,6 +532,7 @@ typedef struct _stack_info_t {
 } stack_info_t;
 
 struct _emit_t {
+ mp_obj_t *error_slot;
  int pass;
 
  bool do_viper_types;
@@ -542,8 +560,9 @@ struct _emit_t {
  ASM_T *as;
 };
 
-emit_t *EXPORT_FUN(new)(mp_uint_t max_num_labels) {
+emit_t *EXPORT_FUN(new)(mp_obj_t *error_slot, mp_uint_t max_num_labels) {
  emit_t *emit = m_new0(emit_t, 1);
+ emit->error_slot = error_slot;
  emit->as = ASM_NEW(max_num_labels);
  return emit;
 }
@@ -571,7 +590,7 @@ STATIC void emit_native_set_native_type(emit_t *emit, mp_uint_t op, mp_uint_t ar
  case MP_QSTR_ptr: type = VTYPE_PTR; break;
  case MP_QSTR_ptr8: type = VTYPE_PTR8; break;
  case MP_QSTR_ptr16: type = VTYPE_PTR16; break;
- default: mp_printf(&mp_plat_print, "ViperTypeError: unknown type %q\n", arg2); return;
+ default: EMIT_NATIVE_VIPER_TYPE_ERROR(emit, "unknown type '%q'", arg2); return;
  }
  if (op == MP_EMIT_NATIVE_TYPE_RETURN) {
  emit->return_vtype = type;
@@ -1288,7 +1307,7 @@ STATIC void emit_native_load_fast(emit_t *emit, qstr qst, mp_uint_t local_num) {
  DEBUG_printf("load_fast(%s, " UINT_FMT ")\n", qstr_str(qst), local_num);
  vtype_kind_t vtype = emit->local_vtype[local_num];
  if (vtype == VTYPE_UNBOUND) {
- mp_printf(&mp_plat_print, "ViperTypeError: local %q used before type known\n", qst);
+ EMIT_NATIVE_VIPER_TYPE_ERROR(emit, "local '%q' used before type known", qst);
  }
  emit_native_pre(emit);
  if (local_num == 0) {
@@ -1438,7 +1457,8 @@ STATIC void emit_native_load_subscr(emit_t *emit) {
  break;
  }
  default:
- mp_printf(&mp_plat_print, "ViperTypeError: can't load from type %d\n", vtype_base);
+ EMIT_NATIVE_VIPER_TYPE_ERROR(emit,
+ "can't load from '%q'", vtype_to_qstr(vtype_base));
  }
  } else {
  // index is not an immediate
@@ -1464,7 +1484,8 @@ STATIC void emit_native_load_subscr(emit_t *emit) {
  break;
  }
  default:
- mp_printf(&mp_plat_print, "ViperTypeError: can't load from type %d\n", vtype_base);
+ EMIT_NATIVE_VIPER_TYPE_ERROR(emit,
+ "can't load from '%q'", vtype_to_qstr(vtype_base));
  }
  }
  emit_post_push_reg(emit, VTYPE_INT, REG_RET);
@@ -1495,7 +1516,9 @@ STATIC void emit_native_store_fast(emit_t *emit, qstr qst, mp_uint_t local_num)
  emit->local_vtype[local_num] = vtype;
  } else if (emit->local_vtype[local_num] != vtype) {
  // type of local is not the same as object stored in it
- mp_printf(&mp_plat_print, "ViperTypeError: type mismatch, local %q has type %d but source object has type %d\n", qst, emit->local_vtype[local_num], vtype);
+ EMIT_NATIVE_VIPER_TYPE_ERROR(emit,
+ "local '%q' has type '%q' but source is '%q'",
+ qst, vtype_to_qstr(emit->local_vtype[local_num]), vtype_to_qstr(vtype));
  }
 }
 
@@ -1625,7 +1648,8 @@ STATIC void emit_native_store_subscr(emit_t *emit) {
  break;
  }
  default:
- mp_printf(&mp_plat_print, "ViperTypeError: can't store to type %d\n", vtype_base);
+ EMIT_NATIVE_VIPER_TYPE_ERROR(emit,
+ "can't store to '%q'", vtype_to_qstr(vtype_base));
  }
  } else {
  // index is not an immediate
@@ -1666,7 +1690,8 @@ STATIC void emit_native_store_subscr(emit_t *emit) {
  break;
  }
  default:
- mp_printf(&mp_plat_print, "ViperTypeError: can't store to type %d\n", vtype_base);
+ EMIT_NATIVE_VIPER_TYPE_ERROR(emit,
+ "can't store to '%q'", vtype_to_qstr(vtype_base));
  }
  }
 
@@ -1761,25 +1786,21 @@ STATIC void emit_native_jump(emit_t *emit, mp_uint_t label) {
 
 STATIC void emit_native_jump_helper(emit_t *emit, bool pop) {
  vtype_kind_t vtype = peek_vtype(emit, 0);
- switch (vtype) {
- case VTYPE_PYOBJ:
- emit_pre_pop_reg(emit, &vtype, REG_ARG_1);
- if (!pop) {
- adjust_stack(emit, 1);
- }
- emit_call(emit, MP_F_OBJ_IS_TRUE);
- break;
- case VTYPE_BOOL:
- case VTYPE_INT:
- case VTYPE_UINT:
- emit_pre_pop_reg(emit, &vtype, REG_RET);
- if (!pop) {
- adjust_stack(emit, 1);
- }
- break;
- default:
- mp_printf(&mp_plat_print, "ViperTypeError: expecting a bool or pyobj, got %d\n", vtype);
- assert(0);
+ if (vtype == VTYPE_PYOBJ) {
+ emit_pre_pop_reg(emit, &vtype, REG_ARG_1);
+ if (!pop) {
+ adjust_stack(emit, 1);
+ }
+ emit_call(emit, MP_F_OBJ_IS_TRUE);
+ } else {
+ emit_pre_pop_reg(emit, &vtype, REG_RET);
+ if (!pop) {
+ adjust_stack(emit, 1);
+ }
+ if (!(vtype == VTYPE_BOOL || vtype == VTYPE_INT || vtype == VTYPE_UINT)) {
+ EMIT_NATIVE_VIPER_TYPE_ERROR(emit,
+ "can't implicitly convert '%q' to 'bool'", vtype_to_qstr(vtype));
+ }
  }
  // For non-pop need to save the vtype so that emit_native_adjust_stack_size
  // can use it. This is a bit of a hack.
@@ -2056,7 +2077,9 @@ STATIC void emit_native_binary_op(emit_t *emit, mp_binary_op_t op) {
  }
  emit_post_push_reg(emit, VTYPE_PYOBJ, REG_RET);
  } else {
- mp_printf(&mp_plat_print, "ViperTypeError: can't do binary op between types %d and %d\n", vtype_lhs, vtype_rhs);
+ EMIT_NATIVE_VIPER_TYPE_ERROR(emit,
+ "can't do binary op between '%q' and '%q'",
+ vtype_to_qstr(vtype_lhs), vtype_to_qstr(vtype_rhs));
  emit_post_push_reg(emit, VTYPE_PYOBJ, REG_RET);
  }
 }
@@ -2302,7 +2325,9 @@ STATIC void emit_native_return_value(emit_t *emit) {
  vtype_kind_t vtype;
  emit_pre_pop_reg(emit, &vtype, REG_RET);
  if (vtype != emit->return_vtype) {
- mp_printf(&mp_plat_print, "ViperTypeError: incompatible return type\n");
+ EMIT_NATIVE_VIPER_TYPE_ERROR(emit,
+ "return expected '%q' but got '%q'",
+ vtype_to_qstr(emit->return_vtype), vtype_to_qstr(vtype));
  }
  }
  } else {
@@ -2320,7 +2345,7 @@ STATIC void emit_native_raise_varargs(emit_t *emit, mp_uint_t n_args) {
  vtype_kind_t vtype_exc;
  emit_pre_pop_reg(emit, &vtype_exc, REG_ARG_1); // arg1 = object to raise
  if (vtype_exc != VTYPE_PYOBJ) {
- mp_printf(&mp_plat_print, "ViperTypeError: must raise an object\n");
+ EMIT_NATIVE_VIPER_TYPE_ERROR(emit, "must raise an object");
  }
  // TODO probably make this 1 call to the runtime (which could even call convert, native_raise(obj, type))
  emit_call(emit, MP_F_NATIVE_RAISE);

py/modbuiltins.c

@@ -703,6 +703,9 @@ STATIC const mp_map_elem_t mp_module_builtins_globals_table[] = {
  { MP_OBJ_NEW_QSTR(MP_QSTR_UnicodeError), (mp_obj_t)&mp_type_UnicodeError },
  #endif
  { MP_OBJ_NEW_QSTR(MP_QSTR_ValueError), (mp_obj_t)&mp_type_ValueError },
+ #if MICROPY_EMIT_NATIVE
+ { MP_OBJ_NEW_QSTR(MP_QSTR_ViperTypeError), (mp_obj_t)&mp_type_ViperTypeError },
+ #endif
  { MP_OBJ_NEW_QSTR(MP_QSTR_ZeroDivisionError), (mp_obj_t)&mp_type_ZeroDivisionError },
  // Somehow CPython managed to have OverflowError not inherit from ValueError ;-/
  // TODO: For MICROPY_CPYTHON_COMPAT==0 use ValueError to avoid exc proliferation

py/obj.h

@@ -434,6 +434,7 @@ extern const mp_obj_type_t mp_type_SystemExit;
 extern const mp_obj_type_t mp_type_TypeError;
 extern const mp_obj_type_t mp_type_UnicodeError;
 extern const mp_obj_type_t mp_type_ValueError;
+extern const mp_obj_type_t mp_type_ViperTypeError;
 extern const mp_obj_type_t mp_type_ZeroDivisionError;
 
 // Constant objects, globally accessible

py/objexcept.c

@@ -252,6 +252,10 @@ MP_DEFINE_EXCEPTION(Exception, BaseException)
  */
  //MP_DEFINE_EXCEPTION(SystemError, Exception)
  MP_DEFINE_EXCEPTION(TypeError, Exception)
+#if MICROPY_EMIT_NATIVE
+ MP_DEFINE_EXCEPTION_BASE(TypeError)
+ MP_DEFINE_EXCEPTION(ViperTypeError, TypeError)
+#endif
  MP_DEFINE_EXCEPTION(ValueError, Exception)
 #if MICROPY_PY_BUILTINS_STR_UNICODE
  MP_DEFINE_EXCEPTION_BASE(ValueError)

py/qstrdefs.h

@@ -144,6 +144,9 @@ Q(SystemExit)
 Q(TypeError)
 Q(UnboundLocalError)
 Q(ValueError)
+#if MICROPY_EMIT_NATIVE
+Q(ViperTypeError)
+#endif
 Q(ZeroDivisionError)
 #if MICROPY_PY_BUILTINS_STR_UNICODE
 Q(UnicodeError)