add traceback object

Author: microdev1

lib/utils/pyexec.c

@@ -242,7 +242,7 @@ STATIC mp_uint_t mp_reader_stdin_readbyte(void *data) {
         mp_hal_stdout_tx_strn("\x04", 1); // indicate end to host
         if (c == CHAR_CTRL_C) {
             #if MICROPY_KBD_EXCEPTION
-            MP_STATE_VM(mp_kbd_exception).traceback_data = NULL;
+            MP_STATE_VM(mp_kbd_exception).traceback->data = NULL;
             nlr_raise(MP_OBJ_FROM_PTR(&MP_STATE_VM(mp_kbd_exception)));
             #else
             mp_raise_type(&mp_type_KeyboardInterrupt);

py/mpstate.h

@@ -120,6 +120,9 @@ typedef struct _mp_state_vm_t {
 
     qstr_pool_t *last_pool;
 
+    // non-heap memory for creating a traceback if we can't allocate RAM
+    mp_obj_traceback_t mp_emergency_traceback_obj;
+
     // non-heap memory for creating an exception if we can't allocate RAM
     mp_obj_exception_t mp_emergency_exception_obj;
 
@@ -137,6 +140,8 @@ typedef struct _mp_state_vm_t {
     #if MICROPY_KBD_EXCEPTION
     // exception object of type KeyboardInterrupt
     mp_obj_exception_t mp_kbd_exception;
+    // traceback object to store traceback
+    mp_obj_traceback_t mp_kbd_traceback;
     #endif
 
     // exception object of type ReloadException

py/obj.h

@@ -692,6 +692,7 @@ extern const mp_obj_type_t mp_type_bytearray;
 extern const mp_obj_type_t mp_type_memoryview;
 extern const mp_obj_type_t mp_type_float;
 extern const mp_obj_type_t mp_type_complex;
+extern const mp_obj_type_t mp_type_traceback;
 extern const mp_obj_type_t mp_type_tuple;
 extern const mp_obj_type_t mp_type_list;
 extern const mp_obj_type_t mp_type_map; // map (the python builtin, not the dict implementation detail)
@@ -791,6 +792,7 @@ extern const struct _mp_obj_bool_t mp_const_true_obj;
 extern const struct _mp_obj_str_t mp_const_empty_bytes_obj;
 extern const struct _mp_obj_tuple_t mp_const_empty_tuple_obj;
 extern const struct _mp_obj_dict_t mp_const_empty_dict_obj;
+extern const struct _mp_obj_traceback_t mp_const_empty_traceback_obj;
 extern const struct _mp_obj_singleton_t mp_const_ellipsis_obj;
 extern const struct _mp_obj_singleton_t mp_const_notimplemented_obj;
 extern const struct _mp_obj_exception_t mp_const_GeneratorExit_obj;

py/objexcept.c

@@ -156,7 +156,15 @@ mp_obj_t mp_obj_exception_make_new(const mp_obj_type_t *type, size_t n_args, con
 
     // Populate the exception object
     o_exc->base.type = type;
-    o_exc->traceback_data = NULL;
+
+    // Try to allocate memory for the traceback, with fallback to emergency traceback object
+    o_exc->traceback = m_new_obj_maybe(mp_obj_traceback_t);
+    if (o_exc->traceback == NULL) {
+        o_exc->traceback = &MP_STATE_VM(mp_emergency_traceback_obj);
+    }
+
+    // Populate the traceback object
+    *o_exc->traceback = mp_const_empty_traceback_obj;
 
     mp_obj_tuple_t *o_tuple;
     if (n_args == 0) {
@@ -208,22 +216,25 @@ void mp_obj_exception_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
     mp_obj_exception_t *self = MP_OBJ_TO_PTR(self_in);
     if (dest[0] != MP_OBJ_NULL) {
         // store/delete attribute
-        if (attr == MP_QSTR___traceback__ && dest[1] == mp_const_none) {
-            // We allow 'exc.__traceback__ = None' assignment as low-level
-            // optimization of pre-allocating exception instance and raising
-            // it repeatedly - this avoids memory allocation during raise.
-            // However, uPy will keep adding traceback entries to such
-            // exception instance, so before throwing it, traceback should
-            // be cleared like above.
-            self->traceback_len = 0;
+        if (attr == MP_QSTR___traceback__) {
+            if (dest[1] == mp_const_none) {
+                self->traceback->data = NULL;
+            } else {
+                if (!mp_obj_is_type(dest[1], &mp_type_traceback)) {
+                    mp_raise_TypeError(MP_ERROR_TEXT("invalid traceback"));
+                }
+                self->traceback = MP_OBJ_TO_PTR(dest[1]);
+            }
             dest[0] = MP_OBJ_NULL; // indicate success
         }
         return;
     }
     if (attr == MP_QSTR_args) {
         dest[0] = MP_OBJ_FROM_PTR(self->args);
-    } else if (self->base.type == &mp_type_StopIteration && attr == MP_QSTR_value) {
+    } else if (attr == MP_QSTR_value && self->base.type == &mp_type_StopIteration) {
         dest[0] = mp_obj_exception_get_value(self_in);
+    } else if (attr == MP_QSTR___traceback__) {
+        dest[0] = (self->traceback->data) ? MP_OBJ_FROM_PTR(self->traceback) : mp_const_none;
     #if MICROPY_CPYTHON_COMPAT
     } else if (mp_obj_is_subclass_fast(MP_OBJ_FROM_PTR(self->base.type), MP_OBJ_FROM_PTR(&mp_type_OSError))) {
         if (attr == MP_QSTR_errno) {
@@ -552,7 +563,7 @@ void mp_obj_exception_clear_traceback(mp_obj_t self_in) {
     GET_NATIVE_EXCEPTION(self, self_in);
     // just set the traceback to the null object
     // we don't want to call any memory management functions here
-    self->traceback_data = NULL;
+    self->traceback->data = NULL;
 }
 
 void mp_obj_exception_add_traceback(mp_obj_t self_in, qstr file, size_t line, qstr block) {
@@ -561,16 +572,16 @@ void mp_obj_exception_add_traceback(mp_obj_t self_in, qstr file, size_t line, qs
     // append this traceback info to traceback data
     // if memory allocation fails (eg because gc is locked), just return
 
-    if (self->traceback_data == NULL) {
-        self->traceback_data = m_new_maybe(size_t, TRACEBACK_ENTRY_LEN);
-        if (self->traceback_data == NULL) {
+    if (self->traceback->data == NULL) {
+        self->traceback->data = m_new_maybe(size_t, TRACEBACK_ENTRY_LEN);
+        if (self->traceback->data == NULL) {
             #if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
             if (mp_emergency_exception_buf_size >= (mp_int_t)(EMG_BUF_TRACEBACK_OFFSET + EMG_BUF_TRACEBACK_SIZE)) {
                 // There is room in the emergency buffer for traceback data
                 size_t *tb = (size_t *)((uint8_t *)MP_STATE_VM(mp_emergency_exception_buf)
                     + EMG_BUF_TRACEBACK_OFFSET);
-                self->traceback_data = tb;
-                self->traceback_alloc = EMG_BUF_TRACEBACK_SIZE / sizeof(size_t);
+                self->traceback->data = tb;
+                self->traceback->alloc = EMG_BUF_TRACEBACK_SIZE / sizeof(size_t);
             } else {
                 // Can't allocate and no room in emergency buffer
                 return;
@@ -581,28 +592,28 @@ void mp_obj_exception_add_traceback(mp_obj_t self_in, qstr file, size_t line, qs
             #endif
         } else {
             // Allocated the traceback data on the heap
-            self->traceback_alloc = TRACEBACK_ENTRY_LEN;
+            self->traceback->alloc = TRACEBACK_ENTRY_LEN;
         }
-        self->traceback_len = 0;
-    } else if (self->traceback_len + TRACEBACK_ENTRY_LEN > self->traceback_alloc) {
+        self->traceback->len = 0;
+    } else if (self->traceback->len + TRACEBACK_ENTRY_LEN > self->traceback->alloc) {
         #if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
-        if (self->traceback_data == (size_t *)MP_STATE_VM(mp_emergency_exception_buf)) {
+        if (self->traceback->data == (size_t *)MP_STATE_VM(mp_emergency_exception_buf)) {
             // Can't resize the emergency buffer
             return;
         }
         #endif
         // be conservative with growing traceback data
-        size_t *tb_data = m_renew_maybe(size_t, self->traceback_data, self->traceback_alloc,
-            self->traceback_alloc + TRACEBACK_ENTRY_LEN, true);
+        size_t *tb_data = m_renew_maybe(size_t, self->traceback->data, self->traceback->alloc,
+            self->traceback->alloc + TRACEBACK_ENTRY_LEN, true);
         if (tb_data == NULL) {
             return;
         }
-        self->traceback_data = tb_data;
-        self->traceback_alloc += TRACEBACK_ENTRY_LEN;
+        self->traceback->data = tb_data;
+        self->traceback->alloc += TRACEBACK_ENTRY_LEN;
     }
 
-    size_t *tb_data = &self->traceback_data[self->traceback_len];
-    self->traceback_len += TRACEBACK_ENTRY_LEN;
+    size_t *tb_data = &self->traceback->data[self->traceback->len];
+    self->traceback->len += TRACEBACK_ENTRY_LEN;
     tb_data[0] = file;
     tb_data[1] = line;
     tb_data[2] = block;
@@ -611,12 +622,12 @@ void mp_obj_exception_add_traceback(mp_obj_t self_in, qstr file, size_t line, qs
 void mp_obj_exception_get_traceback(mp_obj_t self_in, size_t *n, size_t **values) {
     GET_NATIVE_EXCEPTION(self, self_in);
 
-    if (self->traceback_data == NULL) {
+    if (self->traceback->data == NULL) {
         *n = 0;
         *values = NULL;
     } else {
-        *n = self->traceback_len;
-        *values = self->traceback_data;
+        *n = self->traceback->len;
+        *values = self->traceback->data;
     }
 }
 

py/objexcept.h

@@ -28,13 +28,12 @@
 
 #include "py/obj.h"
 #include "py/objtuple.h"
+#include "py/objtraceback.h"
 
 typedef struct _mp_obj_exception_t {
     mp_obj_base_t base;
-    size_t traceback_alloc : (8 * sizeof(size_t) / 2);
-    size_t traceback_len : (8 * sizeof(size_t) / 2);
-    size_t *traceback_data;
     mp_obj_tuple_t *args;
+    mp_obj_traceback_t *traceback;
 } mp_obj_exception_t;
 
 void mp_obj_exception_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind);

py/objgenerator.c

@@ -38,7 +38,7 @@
 #include "supervisor/shared/translate.h"
 
 // Instance of GeneratorExit exception - needed by generator.close()
-const mp_obj_exception_t mp_const_GeneratorExit_obj = {{&mp_type_GeneratorExit}, 0, 0, NULL, (mp_obj_tuple_t *)&mp_const_empty_tuple_obj};
+const mp_obj_exception_t mp_const_GeneratorExit_obj = {{&mp_type_GeneratorExit}, (mp_obj_tuple_t *)&mp_const_empty_tuple_obj, (mp_obj_traceback_t *)&mp_const_empty_traceback_obj};
 
 /******************************************************************************/
 /* generator wrapper                                                          */

py/objtraceback.c

@@ -0,0 +1,42 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2021 microDev
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/runtime.h"
+#include "py/objtraceback.h"
+
+const mp_obj_traceback_t mp_const_empty_traceback_obj = {{&mp_type_traceback}, 0, 0, NULL};
+
+STATIC void mp_obj_traceback_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
+    (void)kind;
+    mp_obj_traceback_t *o = MP_OBJ_TO_PTR(o_in);
+    mp_printf(print, "<traceback object at 0x%p>", o);
+}
+
+const mp_obj_type_t mp_type_traceback = {
+    { &mp_type_type },
+    .name = MP_QSTR_traceback,
+    .print = mp_obj_traceback_print,
+};

py/objtraceback.h

@@ -0,0 +1,39 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2021 microDev
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_PY_OBJTRACEBACK_H
+#define MICROPY_INCLUDED_PY_OBJTRACEBACK_H
+
+#include "py/obj.h"
+
+typedef struct _mp_obj_traceback_t {
+    mp_obj_base_t base;
+    size_t alloc : (8 * sizeof(size_t) / 2);
+    size_t len : (8 * sizeof(size_t) / 2);
+    size_t *data;
+} mp_obj_traceback_t;
+
+#endif // MICROPY_INCLUDED_PY_OBJTRACEBACK_H

py/py.cmake

@@ -95,6 +95,7 @@ set(MICROPY_SOURCE_PY
     ${MICROPY_PY_DIR}/objstr.c
     ${MICROPY_PY_DIR}/objstringio.c
     ${MICROPY_PY_DIR}/objstrunicode.c
+    ${MICROPY_PY_DIR}/objtraceback.c
     ${MICROPY_PY_DIR}/objtuple.c
     ${MICROPY_PY_DIR}/objtype.c
     ${MICROPY_PY_DIR}/objzip.c

py/py.mk

@@ -153,6 +153,7 @@ PY_CORE_O_BASENAME = $(addprefix py/,\
 	objstr.o \
 	objstrunicode.o \
 	objstringio.o \
+	objtraceback.o \
 	objtuple.o \
 	objtype.o \
 	objzip.o \