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review.linaro.org / lite / micropython / ca6723b144501d3ea96a5a79bb18f0947a63fc87 / . / py / parse.c
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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013-2017 Damien P. George
*
* 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 <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <unistd.h> // for ssize_t
#include <assert.h>
#include <string.h>
#include "py/lexer.h"
#include "py/parse.h"
#include "py/parsenum.h"
#include "py/runtime.h"
#include "py/objint.h"
#include "py/objstr.h"
#include "py/builtin.h"
#if MICROPY_ENABLE_COMPILER
#define RULE_ACT_ARG_MASK (0x0f)
#define RULE_ACT_KIND_MASK (0x30)
#define RULE_ACT_ALLOW_IDENT (0x40)
#define RULE_ACT_ADD_BLANK (0x80)
#define RULE_ACT_OR (0x10)
#define RULE_ACT_AND (0x20)
#define RULE_ACT_LIST (0x30)
#define RULE_ARG_KIND_MASK (0xf000)
#define RULE_ARG_ARG_MASK (0x0fff)
#define RULE_ARG_TOK (0x1000)
#define RULE_ARG_RULE (0x2000)
#define RULE_ARG_OPT_RULE (0x3000)
// *FORMAT-OFF*
enum {
// define rules with a compile function
#define DEF_RULE(rule, comp, kind, ...) RULE_##rule,
#define DEF_RULE_NC(rule, kind, ...)
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
RULE_const_object, // special node for a constant, generic Python object
// define rules without a compile function
#define DEF_RULE(rule, comp, kind, ...)
#define DEF_RULE_NC(rule, kind, ...) RULE_##rule,
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
};
// Define an array of actions corresponding to each rule
static const uint8_t rule_act_table[] = {
#define or(n) (RULE_ACT_OR | n)
#define and(n) (RULE_ACT_AND | n)
#define and_ident(n) (RULE_ACT_AND | n | RULE_ACT_ALLOW_IDENT)
#define and_blank(n) (RULE_ACT_AND | n | RULE_ACT_ADD_BLANK)
#define one_or_more (RULE_ACT_LIST | 2)
#define list (RULE_ACT_LIST | 1)
#define list_with_end (RULE_ACT_LIST | 3)
#define DEF_RULE(rule, comp, kind, ...) kind,
#define DEF_RULE_NC(rule, kind, ...)
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
0, // RULE_const_object
#define DEF_RULE(rule, comp, kind, ...)
#define DEF_RULE_NC(rule, kind, ...) kind,
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
#undef or
#undef and
#undef and_ident
#undef and_blank
#undef one_or_more
#undef list
#undef list_with_end
};
// Define the argument data for each rule, as a combined array
static const uint16_t rule_arg_combined_table[] = {
#define tok(t) (RULE_ARG_TOK | MP_TOKEN_##t)
#define rule(r) (RULE_ARG_RULE | RULE_##r)
#define opt_rule(r) (RULE_ARG_OPT_RULE | RULE_##r)
#define DEF_RULE(rule, comp, kind, ...) __VA_ARGS__,
#define DEF_RULE_NC(rule, kind, ...)
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
#define DEF_RULE(rule, comp, kind, ...)
#define DEF_RULE_NC(rule, kind, ...) __VA_ARGS__,
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
#undef tok
#undef rule
#undef opt_rule
};
// Macro to create a list of N identifiers where N is the number of variable arguments to the macro
#define RULE_EXPAND(x) x
#define RULE_PADDING(rule, ...) RULE_PADDING2(rule, __VA_ARGS__, RULE_PADDING_IDS(rule))
#define RULE_PADDING2(rule, ...) RULE_EXPAND(RULE_PADDING3(rule, __VA_ARGS__))
#define RULE_PADDING3(rule, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, ...) __VA_ARGS__
#define RULE_PADDING_IDS(r) PAD13_##r, PAD12_##r, PAD11_##r, PAD10_##r, PAD9_##r, PAD8_##r, PAD7_##r, PAD6_##r, PAD5_##r, PAD4_##r, PAD3_##r, PAD2_##r, PAD1_##r,
// Use an enum to create constants specifying how much room a rule takes in rule_arg_combined_table
enum {
#define DEF_RULE(rule, comp, kind, ...) RULE_PADDING(rule, __VA_ARGS__)
#define DEF_RULE_NC(rule, kind, ...)
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
#define DEF_RULE(rule, comp, kind, ...)
#define DEF_RULE_NC(rule, kind, ...) RULE_PADDING(rule, __VA_ARGS__)
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
};
// Macro to compute the start of a rule in rule_arg_combined_table
#define RULE_ARG_OFFSET(rule, ...) RULE_ARG_OFFSET2(rule, __VA_ARGS__, RULE_ARG_OFFSET_IDS(rule))
#define RULE_ARG_OFFSET2(rule, ...) RULE_EXPAND(RULE_ARG_OFFSET3(rule, __VA_ARGS__))
#define RULE_ARG_OFFSET3(rule, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, ...) _14
#define RULE_ARG_OFFSET_IDS(r) PAD13_##r, PAD12_##r, PAD11_##r, PAD10_##r, PAD9_##r, PAD8_##r, PAD7_##r, PAD6_##r, PAD5_##r, PAD4_##r, PAD3_##r, PAD2_##r, PAD1_##r, PAD0_##r,
// Use the above enum values to create a table of offsets for each rule's arg
// data, which indexes rule_arg_combined_table. The offsets require 9 bits of
// storage but only the lower 8 bits are stored here. The 9th bit is computed
// in get_rule_arg using the FIRST_RULE_WITH_OFFSET_ABOVE_255 constant.
static const uint8_t rule_arg_offset_table[] = {
#define DEF_RULE(rule, comp, kind, ...) RULE_ARG_OFFSET(rule, __VA_ARGS__) & 0xff,
#define DEF_RULE_NC(rule, kind, ...)
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
0, // RULE_const_object
#define DEF_RULE(rule, comp, kind, ...)
#define DEF_RULE_NC(rule, kind, ...) RULE_ARG_OFFSET(rule, __VA_ARGS__) & 0xff,
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
};
// Define a constant that's used to determine the 9th bit of the values in rule_arg_offset_table
static const size_t FIRST_RULE_WITH_OFFSET_ABOVE_255 =
#define DEF_RULE(rule, comp, kind, ...) RULE_ARG_OFFSET(rule, __VA_ARGS__) >= 0x100 ? RULE_##rule :
#define DEF_RULE_NC(rule, kind, ...)
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
#define DEF_RULE(rule, comp, kind, ...)
#define DEF_RULE_NC(rule, kind, ...) RULE_ARG_OFFSET(rule, __VA_ARGS__) >= 0x100 ? RULE_##rule :
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
0;
#if MICROPY_DEBUG_PARSE_RULE_NAME
// Define an array of rule names corresponding to each rule
static const char *const rule_name_table[] = {
#define DEF_RULE(rule, comp, kind, ...) #rule,
#define DEF_RULE_NC(rule, kind, ...)
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
"", // RULE_const_object
#define DEF_RULE(rule, comp, kind, ...)
#define DEF_RULE_NC(rule, kind, ...) #rule,
#include "py/grammar.h"
#undef DEF_RULE
#undef DEF_RULE_NC
};
#endif
// *FORMAT-ON*
typedef struct _rule_stack_t {
size_t src_line : (8 * sizeof(size_t) - 8); // maximum bits storing source line number
size_t rule_id : 8; // this must be large enough to fit largest rule number
size_t arg_i; // this dictates the maximum nodes in a "list" of things
} rule_stack_t;
typedef struct _mp_parse_chunk_t {
size_t alloc;
union {
size_t used;
struct _mp_parse_chunk_t *next;
} union_;
byte data[];
} mp_parse_chunk_t;
typedef struct _parser_t {
size_t rule_stack_alloc;
size_t rule_stack_top;
rule_stack_t *rule_stack;
size_t result_stack_alloc;
size_t result_stack_top;
mp_parse_node_t *result_stack;
mp_lexer_t *lexer;
mp_parse_tree_t tree;
mp_parse_chunk_t *cur_chunk;
#if MICROPY_COMP_CONST
mp_map_t consts;
#endif
} parser_t;
static void push_result_rule(parser_t *parser, size_t src_line, uint8_t rule_id, size_t num_args);
static const uint16_t *get_rule_arg(uint8_t r_id) {
size_t off = rule_arg_offset_table[r_id];
if (r_id >= FIRST_RULE_WITH_OFFSET_ABOVE_255) {
off |= 0x100;
}
return &rule_arg_combined_table[off];
}
static void *parser_alloc(parser_t *parser, size_t num_bytes) {
// use a custom memory allocator to store parse nodes sequentially in large chunks
mp_parse_chunk_t *chunk = parser->cur_chunk;
if (chunk != NULL && chunk->union_.used + num_bytes > chunk->alloc) {
// not enough room at end of previously allocated chunk so try to grow
mp_parse_chunk_t *new_data = (mp_parse_chunk_t *)m_renew_maybe(byte, chunk,
sizeof(mp_parse_chunk_t) + chunk->alloc,
sizeof(mp_parse_chunk_t) + chunk->alloc + num_bytes, false);
if (new_data == NULL) {
// could not grow existing memory; shrink it to fit previous
(void)m_renew_maybe(byte, chunk, sizeof(mp_parse_chunk_t) + chunk->alloc,
sizeof(mp_parse_chunk_t) + chunk->union_.used, false);
chunk->alloc = chunk->union_.used;
chunk->union_.next = parser->tree.chunk;
parser->tree.chunk = chunk;
chunk = NULL;
} else {
// could grow existing memory
chunk->alloc += num_bytes;
}
}
if (chunk == NULL) {
// no previous chunk, allocate a new chunk
size_t alloc = MICROPY_ALLOC_PARSE_CHUNK_INIT;
if (alloc < num_bytes) {
alloc = num_bytes;
}
chunk = (mp_parse_chunk_t *)m_new(byte, sizeof(mp_parse_chunk_t) + alloc);
chunk->alloc = alloc;
chunk->union_.used = 0;
parser->cur_chunk = chunk;
}
byte *ret = chunk->data + chunk->union_.used;
chunk->union_.used += num_bytes;
return ret;
}
#if MICROPY_COMP_CONST_TUPLE
static void parser_free_parse_node_struct(parser_t *parser, mp_parse_node_struct_t *pns) {
mp_parse_chunk_t *chunk = parser->cur_chunk;
if (chunk->data <= (byte *)pns && (byte *)pns < chunk->data + chunk->union_.used) {
size_t num_bytes = sizeof(mp_parse_node_struct_t) + sizeof(mp_parse_node_t) * MP_PARSE_NODE_STRUCT_NUM_NODES(pns);
chunk->union_.used -= num_bytes;
}
}
#endif
static void push_rule(parser_t *parser, size_t src_line, uint8_t rule_id, size_t arg_i) {
if (parser->rule_stack_top >= parser->rule_stack_alloc) {
rule_stack_t *rs = m_renew(rule_stack_t, parser->rule_stack, parser->rule_stack_alloc, parser->rule_stack_alloc + MICROPY_ALLOC_PARSE_RULE_INC);
parser->rule_stack = rs;
parser->rule_stack_alloc += MICROPY_ALLOC_PARSE_RULE_INC;
}
rule_stack_t *rs = &parser->rule_stack[parser->rule_stack_top++];
rs->src_line = src_line;
rs->rule_id = rule_id;
rs->arg_i = arg_i;
}
static void push_rule_from_arg(parser_t *parser, size_t arg) {
assert((arg & RULE_ARG_KIND_MASK) == RULE_ARG_RULE || (arg & RULE_ARG_KIND_MASK) == RULE_ARG_OPT_RULE);
size_t rule_id = arg & RULE_ARG_ARG_MASK;
push_rule(parser, parser->lexer->tok_line, rule_id, 0);
}
static uint8_t pop_rule(parser_t *parser, size_t *arg_i, size_t *src_line) {
parser->rule_stack_top -= 1;
uint8_t rule_id = parser->rule_stack[parser->rule_stack_top].rule_id;
*arg_i = parser->rule_stack[parser->rule_stack_top].arg_i;
*src_line = parser->rule_stack[parser->rule_stack_top].src_line;
return rule_id;
}
#if MICROPY_COMP_CONST_TUPLE
static uint8_t peek_rule(parser_t *parser, size_t n) {
assert(parser->rule_stack_top > n);
return parser->rule_stack[parser->rule_stack_top - 1 - n].rule_id;
}
#endif
bool mp_parse_node_get_int_maybe(mp_parse_node_t pn, mp_obj_t *o) {
if (MP_PARSE_NODE_IS_SMALL_INT(pn)) {
*o = MP_OBJ_NEW_SMALL_INT(MP_PARSE_NODE_LEAF_SMALL_INT(pn));
return true;
} else if (MP_PARSE_NODE_IS_STRUCT_KIND(pn, RULE_const_object)) {
mp_parse_node_struct_t *pns = (mp_parse_node_struct_t *)pn;
*o = mp_parse_node_extract_const_object(pns);
return mp_obj_is_int(*o);
} else {
return false;
}
}
#if MICROPY_COMP_CONST_TUPLE || MICROPY_COMP_CONST
static bool mp_parse_node_is_const(mp_parse_node_t pn) {
if (MP_PARSE_NODE_IS_SMALL_INT(pn)) {
// Small integer.
return true;
} else if (MP_PARSE_NODE_IS_LEAF(pn)) {
// Possible str, or constant literal.
uintptr_t kind = MP_PARSE_NODE_LEAF_KIND(pn);
if (kind == MP_PARSE_NODE_STRING) {
return true;
} else if (kind == MP_PARSE_NODE_TOKEN) {
uintptr_t arg = MP_PARSE_NODE_LEAF_ARG(pn);
return arg == MP_TOKEN_KW_NONE
|| arg == MP_TOKEN_KW_FALSE
|| arg == MP_TOKEN_KW_TRUE
|| arg == MP_TOKEN_ELLIPSIS;
}
} else if (MP_PARSE_NODE_IS_STRUCT_KIND(pn, RULE_const_object)) {
// Constant object.
return true;
} else if (MP_PARSE_NODE_IS_STRUCT_KIND(pn, RULE_atom_paren)) {
// Possible empty tuple.
mp_parse_node_struct_t *pns = (mp_parse_node_struct_t *)pn;
return MP_PARSE_NODE_IS_NULL(pns->nodes[0]);
}
return false;
}
static mp_obj_t mp_parse_node_convert_to_obj(mp_parse_node_t pn) {
assert(mp_parse_node_is_const(pn));
if (MP_PARSE_NODE_IS_SMALL_INT(pn)) {
mp_int_t arg = MP_PARSE_NODE_LEAF_SMALL_INT(pn);
#if MICROPY_DYNAMIC_COMPILER
mp_uint_t sign_mask = -((mp_uint_t)1 << (mp_dynamic_compiler.small_int_bits - 1));
if (!((arg & sign_mask) == 0 || (arg & sign_mask) == sign_mask)) {
// Integer doesn't fit in a small-int, so create a multi-precision int object.
return mp_obj_new_int_from_ll(arg);
}
#endif
return MP_OBJ_NEW_SMALL_INT(arg);
} else if (MP_PARSE_NODE_IS_LEAF(pn)) {
uintptr_t kind = MP_PARSE_NODE_LEAF_KIND(pn);
uintptr_t arg = MP_PARSE_NODE_LEAF_ARG(pn);
if (kind == MP_PARSE_NODE_STRING) {
return MP_OBJ_NEW_QSTR(arg);
} else {
assert(MP_PARSE_NODE_LEAF_KIND(pn) == MP_PARSE_NODE_TOKEN);
switch (arg) {
case MP_TOKEN_KW_NONE:
return mp_const_none;
case MP_TOKEN_KW_FALSE:
return mp_const_false;
case MP_TOKEN_KW_TRUE:
return mp_const_true;
default:
assert(arg == MP_TOKEN_ELLIPSIS);
return MP_OBJ_FROM_PTR(&mp_const_ellipsis_obj);
}
}
} else if (MP_PARSE_NODE_IS_STRUCT_KIND(pn, RULE_const_object)) {
mp_parse_node_struct_t *pns = (mp_parse_node_struct_t *)pn;
return mp_parse_node_extract_const_object(pns);
} else {
assert(MP_PARSE_NODE_IS_STRUCT_KIND(pn, RULE_atom_paren));
assert(MP_PARSE_NODE_IS_NULL(((mp_parse_node_struct_t *)pn)->nodes[0]));
return mp_const_empty_tuple;
}
}
#endif
static bool parse_node_is_const_bool(mp_parse_node_t pn, bool value) {
// Returns true if 'pn' is a constant whose boolean value is equivalent to 'value'
#if MICROPY_COMP_CONST_TUPLE || MICROPY_COMP_CONST
return mp_parse_node_is_const(pn) && mp_obj_is_true(mp_parse_node_convert_to_obj(pn)) == value;
#else
return MP_PARSE_NODE_IS_TOKEN_KIND(pn, value ? MP_TOKEN_KW_TRUE : MP_TOKEN_KW_FALSE)
|| (MP_PARSE_NODE_IS_SMALL_INT(pn) && !!MP_PARSE_NODE_LEAF_SMALL_INT(pn) == value);
#endif
}
bool mp_parse_node_is_const_false(mp_parse_node_t pn) {
return parse_node_is_const_bool(pn, false);
}
bool mp_parse_node_is_const_true(mp_parse_node_t pn) {
return parse_node_is_const_bool(pn, true);
}
size_t mp_parse_node_extract_list(mp_parse_node_t *pn, size_t pn_kind, mp_parse_node_t **nodes) {
if (MP_PARSE_NODE_IS_NULL(*pn)) {
*nodes = NULL;
return 0;
} else if (MP_PARSE_NODE_IS_LEAF(*pn)) {
*nodes = pn;
return 1;
} else {
mp_parse_node_struct_t *pns = (mp_parse_node_struct_t *)(*pn);
if (MP_PARSE_NODE_STRUCT_KIND(pns) != pn_kind) {
*nodes = pn;
return 1;
} else {
*nodes = pns->nodes;
return MP_PARSE_NODE_STRUCT_NUM_NODES(pns);
}
}
}
#if MICROPY_DEBUG_PRINTERS
void mp_parse_node_print(const mp_print_t *print, mp_parse_node_t pn, size_t indent) {
if (MP_PARSE_NODE_IS_STRUCT(pn)) {
mp_printf(print, "[% 4d] ", (int)((mp_parse_node_struct_t *)pn)->source_line);
} else {
mp_printf(print, " ");
}
for (size_t i = 0; i < indent; i++) {
mp_printf(print, " ");
}
if (MP_PARSE_NODE_IS_NULL(pn)) {
mp_printf(print, "NULL\n");
} else if (MP_PARSE_NODE_IS_SMALL_INT(pn)) {
mp_int_t arg = MP_PARSE_NODE_LEAF_SMALL_INT(pn);
mp_printf(print, "int(" INT_FMT ")\n", arg);
} else if (MP_PARSE_NODE_IS_LEAF(pn)) {
uintptr_t arg = MP_PARSE_NODE_LEAF_ARG(pn);
switch (MP_PARSE_NODE_LEAF_KIND(pn)) {
case MP_PARSE_NODE_ID:
mp_printf(print, "id(%s)\n", qstr_str(arg));
break;
case MP_PARSE_NODE_STRING:
mp_printf(print, "str(%s)\n", qstr_str(arg));
break;
default:
assert(MP_PARSE_NODE_LEAF_KIND(pn) == MP_PARSE_NODE_TOKEN);
mp_printf(print, "tok(%u)\n", (uint)arg);
break;
}
} else {
// node must be a mp_parse_node_struct_t
mp_parse_node_struct_t *pns = (mp_parse_node_struct_t *)pn;
if (MP_PARSE_NODE_STRUCT_KIND(pns) == RULE_const_object) {
mp_obj_t obj = mp_parse_node_extract_const_object(pns);
#if MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_D
mp_printf(print, "literal const(%016llx)=", obj);
#else
mp_printf(print, "literal const(%p)=", obj);
#endif
mp_obj_print_helper(print, obj, PRINT_REPR);
mp_printf(print, "\n");
} else {
size_t n = MP_PARSE_NODE_STRUCT_NUM_NODES(pns);
#if MICROPY_DEBUG_PARSE_RULE_NAME
mp_printf(print, "%s(%u) (n=%u)\n", rule_name_table[MP_PARSE_NODE_STRUCT_KIND(pns)], (uint)MP_PARSE_NODE_STRUCT_KIND(pns), (uint)n);
#else
mp_printf(print, "rule(%u) (n=%u)\n", (uint)MP_PARSE_NODE_STRUCT_KIND(pns), (uint)n);
#endif
for (size_t i = 0; i < n; i++) {
mp_parse_node_print(print, pns->nodes[i], indent + 2);
}
}
}
}
#endif // MICROPY_DEBUG_PRINTERS
/*
static void result_stack_show(const mp_print_t *print, parser_t *parser) {
mp_printf(print, "result stack, most recent first\n");
for (ssize_t i = parser->result_stack_top - 1; i >= 0; i--) {
mp_parse_node_print(print, parser->result_stack[i], 0);
}
}
*/
static mp_parse_node_t pop_result(parser_t *parser) {
assert(parser->result_stack_top > 0);
return parser->result_stack[--parser->result_stack_top];
}
static mp_parse_node_t peek_result(parser_t *parser, size_t pos) {
assert(parser->result_stack_top > pos);
return parser->result_stack[parser->result_stack_top - 1 - pos];
}
static void push_result_node(parser_t *parser, mp_parse_node_t pn) {
if (parser->result_stack_top >= parser->result_stack_alloc) {
mp_parse_node_t *stack = m_renew(mp_parse_node_t, parser->result_stack, parser->result_stack_alloc, parser->result_stack_alloc + MICROPY_ALLOC_PARSE_RESULT_INC);
parser->result_stack = stack;
parser->result_stack_alloc += MICROPY_ALLOC_PARSE_RESULT_INC;
}
parser->result_stack[parser->result_stack_top++] = pn;
}
static mp_parse_node_t make_node_const_object(parser_t *parser, size_t src_line, mp_obj_t obj) {
mp_parse_node_struct_t *pn = parser_alloc(parser, sizeof(mp_parse_node_struct_t) + sizeof(mp_obj_t));
pn->source_line = src_line;
#if MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_D
// nodes are 32-bit pointers, but need to store 64-bit object
pn->kind_num_nodes = RULE_const_object | (2 << 8);
pn->nodes[0] = (uint64_t)obj;
pn->nodes[1] = (uint64_t)obj >> 32;
#else
pn->kind_num_nodes = RULE_const_object | (1 << 8);
pn->nodes[0] = (uintptr_t)obj;
#endif
return (mp_parse_node_t)pn;
}
// Create a parse node representing a constant object, possibly optimising the case of
// an integer, by putting the (small) integer value directly in the parse node itself.
static mp_parse_node_t make_node_const_object_optimised(parser_t *parser, size_t src_line, mp_obj_t obj) {
if (mp_obj_is_small_int(obj)) {
mp_int_t val = MP_OBJ_SMALL_INT_VALUE(obj);
#if MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_D
// A parse node is only 32-bits and the small-int value must fit in 31-bits
if (((val ^ (val << 1)) & 0xffffffff80000000) != 0) {
return make_node_const_object(parser, src_line, obj);
}
#endif
#if MICROPY_DYNAMIC_COMPILER
// Check that the integer value fits in target runtime's small-int
mp_uint_t sign_mask = -((mp_uint_t)1 << (mp_dynamic_compiler.small_int_bits - 1));
if (!((val & sign_mask) == 0 || (val & sign_mask) == sign_mask)) {
return make_node_const_object(parser, src_line, obj);
}
#endif
return mp_parse_node_new_small_int(val);
} else {
return make_node_const_object(parser, src_line, obj);
}
}
static void push_result_token(parser_t *parser, uint8_t rule_id) {
mp_parse_node_t pn;
mp_lexer_t *lex = parser->lexer;
if (lex->tok_kind == MP_TOKEN_NAME) {
qstr id = qstr_from_strn(lex->vstr.buf, lex->vstr.len);
#if MICROPY_COMP_CONST
// if name is a standalone identifier, look it up in the table of dynamic constants
mp_map_elem_t *elem;
if (rule_id == RULE_atom
&& (elem = mp_map_lookup(&parser->consts, MP_OBJ_NEW_QSTR(id), MP_MAP_LOOKUP)) != NULL) {
pn = make_node_const_object_optimised(parser, lex->tok_line, elem->value);
} else {
pn = mp_parse_node_new_leaf(MP_PARSE_NODE_ID, id);
}
#else
(void)rule_id;
pn = mp_parse_node_new_leaf(MP_PARSE_NODE_ID, id);
#endif
} else if (lex->tok_kind == MP_TOKEN_INTEGER) {
mp_obj_t o = mp_parse_num_integer(lex->vstr.buf, lex->vstr.len, 0, lex);
pn = make_node_const_object_optimised(parser, lex->tok_line, o);
} else if (lex->tok_kind == MP_TOKEN_FLOAT_OR_IMAG) {
mp_obj_t o = mp_parse_num_float(lex->vstr.buf, lex->vstr.len, true, lex);
pn = make_node_const_object(parser, lex->tok_line, o);
} else if (lex->tok_kind == MP_TOKEN_STRING) {
// Don't automatically intern all strings. Doc strings (which are usually large)
// will be discarded by the compiler, and so we shouldn't intern them.
qstr qst = MP_QSTRnull;
if (lex->vstr.len <= MICROPY_ALLOC_PARSE_INTERN_STRING_LEN) {
// intern short strings
qst = qstr_from_strn(lex->vstr.buf, lex->vstr.len);
} else {
// check if this string is already interned
qst = qstr_find_strn(lex->vstr.buf, lex->vstr.len);
}
if (qst != MP_QSTRnull) {
// qstr exists, make a leaf node
pn = mp_parse_node_new_leaf(MP_PARSE_NODE_STRING, qst);
} else {
// not interned, make a node holding a pointer to the string object
mp_obj_t o = mp_obj_new_str_copy(&mp_type_str, (const byte *)lex->vstr.buf, lex->vstr.len);
pn = make_node_const_object(parser, lex->tok_line, o);
}
} else if (lex->tok_kind == MP_TOKEN_BYTES) {
// make a node holding a pointer to the bytes object
mp_obj_t o = mp_obj_new_bytes((const byte *)lex->vstr.buf, lex->vstr.len);
pn = make_node_const_object(parser, lex->tok_line, o);
} else {
pn = mp_parse_node_new_leaf(MP_PARSE_NODE_TOKEN, lex->tok_kind);
}
push_result_node(parser, pn);
}
#if MICROPY_COMP_CONST_FOLDING
#if MICROPY_COMP_MODULE_CONST
static const mp_rom_map_elem_t mp_constants_table[] = {
#if MICROPY_PY_ERRNO
{ MP_ROM_QSTR(MP_QSTR_errno), MP_ROM_PTR(&mp_module_errno) },
#endif
#if MICROPY_PY_UCTYPES
{ MP_ROM_QSTR(MP_QSTR_uctypes), MP_ROM_PTR(&mp_module_uctypes) },
#endif
// Extra constants as defined by a port
MICROPY_PORT_CONSTANTS
};
static MP_DEFINE_CONST_MAP(mp_constants_map, mp_constants_table);
#endif
static bool fold_logical_constants(parser_t *parser, uint8_t rule_id, size_t *num_args) {
if (rule_id == RULE_or_test
|| rule_id == RULE_and_test) {
// folding for binary logical ops: or and
size_t copy_to = *num_args;
for (size_t i = copy_to; i > 0;) {
mp_parse_node_t pn = peek_result(parser, --i);
parser->result_stack[parser->result_stack_top - copy_to] = pn;
if (i == 0) {
// always need to keep the last value
break;
}
if (rule_id == RULE_or_test) {
if (mp_parse_node_is_const_true(pn)) {
//
break;
} else if (!mp_parse_node_is_const_false(pn)) {
copy_to -= 1;
}
} else {
// RULE_and_test
if (mp_parse_node_is_const_false(pn)) {
break;
} else if (!mp_parse_node_is_const_true(pn)) {
copy_to -= 1;
}
}
}
copy_to -= 1; // copy_to now contains number of args to pop
// pop and discard all the short-circuited expressions
for (size_t i = 0; i < copy_to; ++i) {
pop_result(parser);
}
*num_args -= copy_to;
// we did a complete folding if there's only 1 arg left
return *num_args == 1;
} else if (rule_id == RULE_not_test_2) {
// folding for unary logical op: not
mp_parse_node_t pn = peek_result(parser, 0);
if (mp_parse_node_is_const_false(pn)) {
pn = mp_parse_node_new_leaf(MP_PARSE_NODE_TOKEN, MP_TOKEN_KW_TRUE);
} else if (mp_parse_node_is_const_true(pn)) {
pn = mp_parse_node_new_leaf(MP_PARSE_NODE_TOKEN, MP_TOKEN_KW_FALSE);
} else {
return false;
}
pop_result(parser);
push_result_node(parser, pn);
return true;
}
return false;
}
static bool fold_constants(parser_t *parser, uint8_t rule_id, size_t num_args) {
// this code does folding of arbitrary integer expressions, eg 1 + 2 * 3 + 4
// it does not do partial folding, eg 1 + 2 + x -> 3 + x
mp_obj_t arg0;
if (rule_id == RULE_expr
|| rule_id == RULE_xor_expr
|| rule_id == RULE_and_expr
|| rule_id == RULE_power) {
// folding for binary ops: | ^ & **
mp_parse_node_t pn = peek_result(parser, num_args - 1);
if (!mp_parse_node_get_int_maybe(pn, &arg0)) {
return false;
}
mp_binary_op_t op;
if (rule_id == RULE_expr) {
op = MP_BINARY_OP_OR;
} else if (rule_id == RULE_xor_expr) {
op = MP_BINARY_OP_XOR;
} else if (rule_id == RULE_and_expr) {
op = MP_BINARY_OP_AND;
} else {
op = MP_BINARY_OP_POWER;
}
for (ssize_t i = num_args - 2; i >= 0; --i) {
pn = peek_result(parser, i);
mp_obj_t arg1;
if (!mp_parse_node_get_int_maybe(pn, &arg1)) {
return false;
}
if (op == MP_BINARY_OP_POWER && mp_obj_int_sign(arg1) < 0) {
// ** can't have negative rhs
return false;
}
arg0 = mp_binary_op(op, arg0, arg1);
}
} else if (rule_id == RULE_shift_expr
|| rule_id == RULE_arith_expr
|| rule_id == RULE_term) {
// folding for binary ops: << >> + - * @ / % //
mp_parse_node_t pn = peek_result(parser, num_args - 1);
if (!mp_parse_node_get_int_maybe(pn, &arg0)) {
return false;
}
for (ssize_t i = num_args - 2; i >= 1; i -= 2) {
pn = peek_result(parser, i - 1);
mp_obj_t arg1;
if (!mp_parse_node_get_int_maybe(pn, &arg1)) {
return false;
}
mp_token_kind_t tok = MP_PARSE_NODE_LEAF_ARG(peek_result(parser, i));
if (tok == MP_TOKEN_OP_AT || tok == MP_TOKEN_OP_SLASH) {
// Can't fold @ or /
return false;
}
mp_binary_op_t op = MP_BINARY_OP_LSHIFT + (tok - MP_TOKEN_OP_DBL_LESS);
int rhs_sign = mp_obj_int_sign(arg1);
if (op <= MP_BINARY_OP_RSHIFT) {
// << and >> can't have negative rhs
if (rhs_sign < 0) {
return false;
}
} else if (op >= MP_BINARY_OP_FLOOR_DIVIDE) {
// % and // can't have zero rhs
if (rhs_sign == 0) {
return false;
}
}
arg0 = mp_binary_op(op, arg0, arg1);
}
} else if (rule_id == RULE_factor_2) {
// folding for unary ops: + - ~
mp_parse_node_t pn = peek_result(parser, 0);
if (!mp_parse_node_get_int_maybe(pn, &arg0)) {
return false;
}
mp_token_kind_t tok = MP_PARSE_NODE_LEAF_ARG(peek_result(parser, 1));
mp_unary_op_t op;
if (tok == MP_TOKEN_OP_TILDE) {
op = MP_UNARY_OP_INVERT;
} else {
assert(tok == MP_TOKEN_OP_PLUS || tok == MP_TOKEN_OP_MINUS); // should be
op = MP_UNARY_OP_POSITIVE + (tok - MP_TOKEN_OP_PLUS);
}
arg0 = mp_unary_op(op, arg0);
#if MICROPY_COMP_CONST
} else if (rule_id == RULE_expr_stmt) {
mp_parse_node_t pn1 = peek_result(parser, 0);
if (!MP_PARSE_NODE_IS_NULL(pn1)
&& !(MP_PARSE_NODE_IS_STRUCT_KIND(pn1, RULE_expr_stmt_augassign)
|| MP_PARSE_NODE_IS_STRUCT_KIND(pn1, RULE_expr_stmt_assign_list))) {
// this node is of the form <x> = <y>
mp_parse_node_t pn0 = peek_result(parser, 1);
if (MP_PARSE_NODE_IS_ID(pn0)
&& MP_PARSE_NODE_IS_STRUCT_KIND(pn1, RULE_atom_expr_normal)
&& MP_PARSE_NODE_IS_ID(((mp_parse_node_struct_t *)pn1)->nodes[0])
&& MP_PARSE_NODE_LEAF_ARG(((mp_parse_node_struct_t *)pn1)->nodes[0]) == MP_QSTR_const
&& MP_PARSE_NODE_IS_STRUCT_KIND(((mp_parse_node_struct_t *)pn1)->nodes[1], RULE_trailer_paren)
) {
// code to assign dynamic constants: id = const(value)
// get the id
qstr id = MP_PARSE_NODE_LEAF_ARG(pn0);
// get the value
mp_parse_node_t pn_value = ((mp_parse_node_struct_t *)((mp_parse_node_struct_t *)pn1)->nodes[1])->nodes[0];
if (!mp_parse_node_is_const(pn_value)) {
mp_obj_t exc = mp_obj_new_exception_msg(&mp_type_SyntaxError,
MP_ERROR_TEXT("not a constant"));
mp_obj_exception_add_traceback(exc, parser->lexer->source_name,
((mp_parse_node_struct_t *)pn1)->source_line, MP_QSTRnull);
nlr_raise(exc);
}
mp_obj_t value = mp_parse_node_convert_to_obj(pn_value);
// store the value in the table of dynamic constants
mp_map_elem_t *elem = mp_map_lookup(&parser->consts, MP_OBJ_NEW_QSTR(id), MP_MAP_LOOKUP_ADD_IF_NOT_FOUND);
assert(elem->value == MP_OBJ_NULL);
elem->value = value;
// If the constant starts with an underscore then treat it as a private
// variable and don't emit any code to store the value to the id.
if (qstr_str(id)[0] == '_') {
pop_result(parser); // pop const(value)
pop_result(parser); // pop id
push_result_rule(parser, 0, RULE_pass_stmt, 0); // replace with "pass"
return true;
}
// replace const(value) with value
pop_result(parser);
push_result_node(parser, pn_value);
// finished folding this assignment, but we still want it to be part of the tree
return false;
}
}
return false;
#endif
#if MICROPY_COMP_MODULE_CONST
} else if (rule_id == RULE_atom_expr_normal) {
mp_parse_node_t pn0 = peek_result(parser, 1);
mp_parse_node_t pn1 = peek_result(parser, 0);
if (!(MP_PARSE_NODE_IS_ID(pn0)
&& MP_PARSE_NODE_IS_STRUCT_KIND(pn1, RULE_trailer_period))) {
return false;
}
// id1.id2
// look it up in constant table, see if it can be replaced with an integer
mp_parse_node_struct_t *pns1 = (mp_parse_node_struct_t *)pn1;
assert(MP_PARSE_NODE_IS_ID(pns1->nodes[0]));
qstr q_base = MP_PARSE_NODE_LEAF_ARG(pn0);
qstr q_attr = MP_PARSE_NODE_LEAF_ARG(pns1->nodes[0]);
mp_map_elem_t *elem = mp_map_lookup((mp_map_t *)&mp_constants_map, MP_OBJ_NEW_QSTR(q_base), MP_MAP_LOOKUP);
if (elem == NULL) {
return false;
}
mp_obj_t dest[2];
mp_load_method_maybe(elem->value, q_attr, dest);
if (!(dest[0] != MP_OBJ_NULL && mp_obj_is_int(dest[0]) && dest[1] == MP_OBJ_NULL)) {
return false;
}
arg0 = dest[0];
#endif
} else {
return false;
}
// success folding this rule
for (size_t i = num_args; i > 0; i--) {
pop_result(parser);
}
push_result_node(parser, make_node_const_object_optimised(parser, 0, arg0));
return true;
}
#endif // MICROPY_COMP_CONST_FOLDING
#if MICROPY_COMP_CONST_TUPLE
static bool build_tuple_from_stack(parser_t *parser, size_t src_line, size_t num_args) {
for (size_t i = num_args; i > 0;) {
mp_parse_node_t pn = peek_result(parser, --i);
if (!mp_parse_node_is_const(pn)) {
return false;
}
}
mp_obj_tuple_t *tuple = MP_OBJ_TO_PTR(mp_obj_new_tuple(num_args, NULL));
for (size_t i = num_args; i > 0;) {
mp_parse_node_t pn = pop_result(parser);
tuple->items[--i] = mp_parse_node_convert_to_obj(pn);
if (MP_PARSE_NODE_IS_STRUCT(pn)) {
parser_free_parse_node_struct(parser, (mp_parse_node_struct_t *)pn);
}
}
push_result_node(parser, make_node_const_object(parser, src_line, MP_OBJ_FROM_PTR(tuple)));
return true;
}
static bool build_tuple(parser_t *parser, size_t src_line, uint8_t rule_id, size_t num_args) {
if (rule_id == RULE_testlist_comp) {
if (peek_rule(parser, 0) == RULE_atom_paren) {
// Tuple of the form "(a,)".
return build_tuple_from_stack(parser, src_line, num_args);
}
}
if (rule_id == RULE_testlist_comp_3c) {
assert(peek_rule(parser, 0) == RULE_testlist_comp_3b);
assert(peek_rule(parser, 1) == RULE_testlist_comp);
if (peek_rule(parser, 2) == RULE_atom_paren) {
// Tuple of the form "(a, b)".
if (build_tuple_from_stack(parser, src_line, num_args)) {
parser->rule_stack_top -= 2; // discard 2 rules
return true;
}
}
}
if (rule_id == RULE_testlist_star_expr
|| rule_id == RULE_testlist
|| rule_id == RULE_subscriptlist) {
// Tuple of the form:
// - x = a, b
// - return a, b
// - for x in a, b: pass
// - x[a, b]
return build_tuple_from_stack(parser, src_line, num_args);
}
return false;
}
#endif
static void push_result_rule(parser_t *parser, size_t src_line, uint8_t rule_id, size_t num_args) {
// Simplify and optimise certain rules, to reduce memory usage and simplify the compiler.
if (rule_id == RULE_atom_paren) {
// Remove parenthesis around a single expression if possible.
// This atom_paren rule always has a single argument, and after this
// optimisation that argument is either NULL or testlist_comp.
mp_parse_node_t pn = peek_result(parser, 0);
if (MP_PARSE_NODE_IS_NULL(pn)) {
// need to keep parenthesis for ()
} else if (MP_PARSE_NODE_IS_STRUCT_KIND(pn, RULE_testlist_comp)) {
// need to keep parenthesis for (a, b, ...)
} else {
// parenthesis around a single expression, so it's just the expression
return;
}
} else if (rule_id == RULE_testlist_comp) {
// The testlist_comp rule can be the sole argument to either atom_parent
// or atom_bracket, for (...) and [...] respectively.
assert(num_args == 2);
mp_parse_node_t pn = peek_result(parser, 0);
if (MP_PARSE_NODE_IS_STRUCT(pn)) {
mp_parse_node_struct_t *pns = (mp_parse_node_struct_t *)pn;
if (MP_PARSE_NODE_STRUCT_KIND(pns) == RULE_testlist_comp_3b) {
// tuple of one item, with trailing comma
pop_result(parser);
--num_args;
} else if (MP_PARSE_NODE_STRUCT_KIND(pns) == RULE_testlist_comp_3c) {
// tuple of many items, convert testlist_comp_3c to testlist_comp
pop_result(parser);
assert(pn == peek_result(parser, 0));
pns->kind_num_nodes = rule_id | MP_PARSE_NODE_STRUCT_NUM_NODES(pns) << 8;
return;
} else if (MP_PARSE_NODE_STRUCT_KIND(pns) == RULE_comp_for) {
// generator expression
} else {
// tuple with 2 items
}
} else {
// tuple with 2 items
}
} else if (rule_id == RULE_testlist_comp_3c) {
// steal first arg of outer testlist_comp rule
++num_args;
}
#if MICROPY_COMP_CONST_FOLDING
if (fold_logical_constants(parser, rule_id, &num_args)) {
// we folded this rule so return straight away
return;
}
if (fold_constants(parser, rule_id, num_args)) {
// we folded this rule so return straight away
return;
}
#endif
#if MICROPY_COMP_CONST_TUPLE
if (build_tuple(parser, src_line, rule_id, num_args)) {
// we built a tuple from this rule so return straight away
return;
}
#endif
mp_parse_node_struct_t *pn = parser_alloc(parser, sizeof(mp_parse_node_struct_t) + sizeof(mp_parse_node_t) * num_args);
pn->source_line = src_line;
pn->kind_num_nodes = (rule_id & 0xff) | (num_args << 8);
for (size_t i = num_args; i > 0; i--) {
pn->nodes[i - 1] = pop_result(parser);
}
if (rule_id == RULE_testlist_comp_3c) {
// need to push something non-null to replace stolen first arg of testlist_comp
push_result_node(parser, (mp_parse_node_t)pn);
}
push_result_node(parser, (mp_parse_node_t)pn);
}
mp_parse_tree_t mp_parse(mp_lexer_t *lex, mp_parse_input_kind_t input_kind) {
// Set exception handler to free the lexer if an exception is raised.
MP_DEFINE_NLR_JUMP_CALLBACK_FUNCTION_1(ctx, mp_lexer_free, lex);
nlr_push_jump_callback(&ctx.callback, mp_call_function_1_from_nlr_jump_callback);
// initialise parser and allocate memory for its stacks
parser_t parser;
parser.rule_stack_alloc = MICROPY_ALLOC_PARSE_RULE_INIT;
parser.rule_stack_top = 0;
parser.rule_stack = m_new(rule_stack_t, parser.rule_stack_alloc);
parser.result_stack_alloc = MICROPY_ALLOC_PARSE_RESULT_INIT;
parser.result_stack_top = 0;
parser.result_stack = m_new(mp_parse_node_t, parser.result_stack_alloc);
parser.lexer = lex;
parser.tree.chunk = NULL;
parser.cur_chunk = NULL;
#if MICROPY_COMP_CONST
mp_map_init(&parser.consts, 0);
#endif
// work out the top-level rule to use, and push it on the stack
size_t top_level_rule;
switch (input_kind) {
case MP_PARSE_SINGLE_INPUT:
top_level_rule = RULE_single_input;
break;
case MP_PARSE_EVAL_INPUT:
top_level_rule = RULE_eval_input;
break;
default:
top_level_rule = RULE_file_input;
}
push_rule(&parser, lex->tok_line, top_level_rule, 0);
// parse!
bool backtrack = false;
for (;;) {
next_rule:
if (parser.rule_stack_top == 0) {
break;
}
// Pop the next rule to process it
size_t i; // state for the current rule
size_t rule_src_line; // source line for the first token matched by the current rule
uint8_t rule_id = pop_rule(&parser, &i, &rule_src_line);
uint8_t rule_act = rule_act_table[rule_id];
const uint16_t *rule_arg = get_rule_arg(rule_id);
size_t n = rule_act & RULE_ACT_ARG_MASK;
#if 0
// debugging
printf("depth=" UINT_FMT " ", parser.rule_stack_top);
for (int j = 0; j < parser.rule_stack_top; ++j) {
printf(" ");
}
printf("%s n=" UINT_FMT " i=" UINT_FMT " bt=%d\n", rule_name_table[rule_id], n, i, backtrack);
#endif
switch (rule_act & RULE_ACT_KIND_MASK) {
case RULE_ACT_OR:
if (i > 0 && !backtrack) {
goto next_rule;
} else {
backtrack = false;
}
for (; i < n; ++i) {
uint16_t kind = rule_arg[i] & RULE_ARG_KIND_MASK;
if (kind == RULE_ARG_TOK) {
if (lex->tok_kind == (rule_arg[i] & RULE_ARG_ARG_MASK)) {
push_result_token(&parser, rule_id);
mp_lexer_to_next(lex);
goto next_rule;
}
} else {
assert(kind == RULE_ARG_RULE);
if (i + 1 < n) {
push_rule(&parser, rule_src_line, rule_id, i + 1); // save this or-rule
}
push_rule_from_arg(&parser, rule_arg[i]); // push child of or-rule
goto next_rule;
}
}
backtrack = true;
break;
case RULE_ACT_AND: {
// failed, backtrack if we can, else syntax error
if (backtrack) {
assert(i > 0);
if ((rule_arg[i - 1] & RULE_ARG_KIND_MASK) == RULE_ARG_OPT_RULE) {
// an optional rule that failed, so continue with next arg
push_result_node(&parser, MP_PARSE_NODE_NULL);
backtrack = false;
} else {
// a mandatory rule that failed, so propagate backtrack
if (i > 1) {
// already eaten tokens so can't backtrack
goto syntax_error;
} else {
goto next_rule;
}
}
}
// progress through the rule
for (; i < n; ++i) {
if ((rule_arg[i] & RULE_ARG_KIND_MASK) == RULE_ARG_TOK) {
// need to match a token
mp_token_kind_t tok_kind = rule_arg[i] & RULE_ARG_ARG_MASK;
if (lex->tok_kind == tok_kind) {
// matched token
if (tok_kind == MP_TOKEN_NAME) {
push_result_token(&parser, rule_id);
}
mp_lexer_to_next(lex);
} else {
// failed to match token
if (i > 0) {
// already eaten tokens so can't backtrack
goto syntax_error;
} else {
// this rule failed, so backtrack
backtrack = true;
goto next_rule;
}
}
} else {
push_rule(&parser, rule_src_line, rule_id, i + 1); // save this and-rule
push_rule_from_arg(&parser, rule_arg[i]); // push child of and-rule
goto next_rule;
}
}
assert(i == n);
// matched the rule, so now build the corresponding parse_node
#if !MICROPY_ENABLE_DOC_STRING
// this code discards lonely statements, such as doc strings
if (input_kind != MP_PARSE_SINGLE_INPUT && rule_id == RULE_expr_stmt && peek_result(&parser, 0) == MP_PARSE_NODE_NULL) {
mp_parse_node_t p = peek_result(&parser, 1);
if ((MP_PARSE_NODE_IS_LEAF(p) && !MP_PARSE_NODE_IS_ID(p))
|| MP_PARSE_NODE_IS_STRUCT_KIND(p, RULE_const_object)) {
pop_result(&parser); // MP_PARSE_NODE_NULL
pop_result(&parser); // const expression (leaf or RULE_const_object)
// Pushing the "pass" rule here will overwrite any RULE_const_object
// entry that was on the result stack, allowing the GC to reclaim
// the memory from the const object when needed.
push_result_rule(&parser, rule_src_line, RULE_pass_stmt, 0);
break;
}
}
#endif
// count number of arguments for the parse node
i = 0;
size_t num_not_nil = 0;
for (size_t x = n; x > 0;) {
--x;
if ((rule_arg[x] & RULE_ARG_KIND_MASK) == RULE_ARG_TOK) {
mp_token_kind_t tok_kind = rule_arg[x] & RULE_ARG_ARG_MASK;
if (tok_kind == MP_TOKEN_NAME) {
// only tokens which were names are pushed to stack
i += 1;
num_not_nil += 1;
}
} else {
// rules are always pushed
if (peek_result(&parser, i) != MP_PARSE_NODE_NULL) {
num_not_nil += 1;
}
i += 1;
}
}
if (num_not_nil == 1 && (rule_act & RULE_ACT_ALLOW_IDENT)) {
// this rule has only 1 argument and should not be emitted
mp_parse_node_t pn = MP_PARSE_NODE_NULL;
for (size_t x = 0; x < i; ++x) {
mp_parse_node_t pn2 = pop_result(&parser);
if (pn2 != MP_PARSE_NODE_NULL) {
pn = pn2;
}
}
push_result_node(&parser, pn);
} else {
// this rule must be emitted
if (rule_act & RULE_ACT_ADD_BLANK) {
// and add an extra blank node at the end (used by the compiler to store data)
push_result_node(&parser, MP_PARSE_NODE_NULL);
i += 1;
}
push_result_rule(&parser, rule_src_line, rule_id, i);
}
break;
}
default: {
assert((rule_act & RULE_ACT_KIND_MASK) == RULE_ACT_LIST);
// n=2 is: item item*
// n=1 is: item (sep item)*
// n=3 is: item (sep item)* [sep]
bool had_trailing_sep;
if (backtrack) {
list_backtrack:
had_trailing_sep = false;
if (n == 2) {
if (i == 1) {
// fail on item, first time round; propagate backtrack
goto next_rule;
} else {
// fail on item, in later rounds; finish with this rule
backtrack = false;
}
} else {
if (i == 1) {
// fail on item, first time round; propagate backtrack
goto next_rule;
} else if ((i & 1) == 1) {
// fail on item, in later rounds; have eaten tokens so can't backtrack
if (n == 3) {
// list allows trailing separator; finish parsing list
had_trailing_sep = true;
backtrack = false;
} else {
// list doesn't allowing trailing separator; fail
goto syntax_error;
}
} else {
// fail on separator; finish parsing list
backtrack = false;
}
}
} else {
for (;;) {
size_t arg = rule_arg[i & 1 & n];
if ((arg & RULE_ARG_KIND_MASK) == RULE_ARG_TOK) {
if (lex->tok_kind == (arg & RULE_ARG_ARG_MASK)) {
if (i & 1 & n) {
// separators which are tokens are not pushed to result stack
} else {
push_result_token(&parser, rule_id);
}
mp_lexer_to_next(lex);
// got element of list, so continue parsing list
i += 1;
} else {
// couldn't get element of list
i += 1;
backtrack = true;
goto list_backtrack;
}
} else {
assert((arg & RULE_ARG_KIND_MASK) == RULE_ARG_RULE);
push_rule(&parser, rule_src_line, rule_id, i + 1); // save this list-rule
push_rule_from_arg(&parser, arg); // push child of list-rule
goto next_rule;
}
}
}
assert(i >= 1);
// compute number of elements in list, result in i
i -= 1;
if ((n & 1) && (rule_arg[1] & RULE_ARG_KIND_MASK) == RULE_ARG_TOK) {
// don't count separators when they are tokens
i = (i + 1) / 2;
}
if (i == 1) {
// list matched single item
if (had_trailing_sep) {
// if there was a trailing separator, make a list of a single item
push_result_rule(&parser, rule_src_line, rule_id, i);
} else {
// just leave single item on stack (ie don't wrap in a list)
}
} else {
push_result_rule(&parser, rule_src_line, rule_id, i);
}
break;
}
}
}
#if MICROPY_COMP_CONST
mp_map_deinit(&parser.consts);
#endif
// truncate final chunk and link into chain of chunks
if (parser.cur_chunk != NULL) {
(void)m_renew_maybe(byte, parser.cur_chunk,
sizeof(mp_parse_chunk_t) + parser.cur_chunk->alloc,
sizeof(mp_parse_chunk_t) + parser.cur_chunk->union_.used,
false);
parser.cur_chunk->alloc = parser.cur_chunk->union_.used;
parser.cur_chunk->union_.next = parser.tree.chunk;
parser.tree.chunk = parser.cur_chunk;
}
if (
lex->tok_kind != MP_TOKEN_END // check we are at the end of the token stream
|| parser.result_stack_top == 0 // check that we got a node (can fail on empty input)
) {
syntax_error:;
mp_obj_t exc;
if (lex->tok_kind == MP_TOKEN_INDENT) {
exc = mp_obj_new_exception_msg(&mp_type_IndentationError,
MP_ERROR_TEXT("unexpected indent"));
} else if (lex->tok_kind == MP_TOKEN_DEDENT_MISMATCH) {
exc = mp_obj_new_exception_msg(&mp_type_IndentationError,
MP_ERROR_TEXT("unindent doesn't match any outer indent level"));
#if MICROPY_PY_FSTRINGS
} else if (lex->tok_kind == MP_TOKEN_MALFORMED_FSTRING) {
exc = mp_obj_new_exception_msg(&mp_type_SyntaxError,
MP_ERROR_TEXT("malformed f-string"));
#endif
} else {
exc = mp_obj_new_exception_msg(&mp_type_SyntaxError,
MP_ERROR_TEXT("invalid syntax"));
}
// add traceback to give info about file name and location
// we don't have a 'block' name, so just pass the NULL qstr to indicate this
mp_obj_exception_add_traceback(exc, lex->source_name, lex->tok_line, MP_QSTRnull);
nlr_raise(exc);
}
// get the root parse node that we created
assert(parser.result_stack_top == 1);
parser.tree.root = parser.result_stack[0];
// free the memory that we don't need anymore
m_del(rule_stack_t, parser.rule_stack, parser.rule_stack_alloc);
m_del(mp_parse_node_t, parser.result_stack, parser.result_stack_alloc);
// Deregister exception handler and free the lexer.
nlr_pop_jump_callback(true);
return parser.tree;
}
void mp_parse_tree_clear(mp_parse_tree_t *tree) {
mp_parse_chunk_t *chunk = tree->chunk;
while (chunk != NULL) {
mp_parse_chunk_t *next = chunk->union_.next;
m_del(byte, chunk, sizeof(mp_parse_chunk_t) + chunk->alloc);
chunk = next;
}
tree->chunk = NULL; // Avoid dangling pointer that may live on stack
}
#endif // MICROPY_ENABLE_COMPILER