text: /*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2013-2020 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 <stdint.h>
  #include <stdio.h>
  #include <string.h>
  #include <assert.h>
  
  #include "py/reader.h"
  #include "py/nativeglue.h"
  #include "py/persistentcode.h"
  #include "py/bc0.h"
  #include "py/objstr.h"
  #include "py/mpthread.h"
  
  #if MICROPY_PERSISTENT_CODE_LOAD || MICROPY_PERSISTENT_CODE_SAVE
  
  #include "py/smallint.h"
  
  #define QSTR_LAST_STATIC MP_QSTR_zip
  
  #if MICROPY_DYNAMIC_COMPILER
  #define MPY_FEATURE_ARCH_DYNAMIC mp_dynamic_compiler.native_arch
  #else
  #define MPY_FEATURE_ARCH_DYNAMIC MPY_FEATURE_ARCH
  #endif
  
  typedef struct _bytecode_prelude_t {
      uint n_state;
      uint n_exc_stack;
      uint scope_flags;
      uint n_pos_args;
      uint n_kwonly_args;
      uint n_def_pos_args;
      uint code_info_size;
  } bytecode_prelude_t;
  
  #endif // MICROPY_PERSISTENT_CODE_LOAD || MICROPY_PERSISTENT_CODE_SAVE
  
  #if MICROPY_PERSISTENT_CODE_LOAD
  
  #include "py/parsenum.h"
  
  STATIC int read_byte(mp_reader_t *reader);
  STATIC size_t read_uint(mp_reader_t *reader);
  
  #if MICROPY_EMIT_MACHINE_CODE
  
  typedef struct _reloc_info_t {
      mp_reader_t *reader;
      uint8_t *rodata;
      uint8_t *bss;
  } reloc_info_t;
  
  void mp_native_relocate(void *ri_in, uint8_t *text, uintptr_t reloc_text) {
      // Relocate native code
      reloc_info_t *ri = ri_in;
      uint8_t op;
      uintptr_t *addr_to_adjust = NULL;
      while ((op = read_byte(ri->reader)) != 0xff) {
          if (op & 1) {
              // Point to new location to make adjustments
              size_t addr = read_uint(ri->reader);
              if ((addr & 1) == 0) {
                  // Point to somewhere in text
                  addr_to_adjust = &((uintptr_t *)text)[addr >> 1];
              } else {
                  // Point to somewhere in rodata
                  addr_to_adjust = &((uintptr_t *)ri->rodata)[addr >> 1];
              }
          }
          op >>= 1;
          uintptr_t dest;
          size_t n = 1;
          if (op <= 5) {
              if (op & 1) {
                  // Read in number of adjustments to make
                  n = read_uint(ri->reader);
              }
              op >>= 1;
              if (op == 0) {
                  // Destination is text
                  dest = reloc_text;
              } else if (op == 1) {
                  // Destination is rodata
                  dest = (uintptr_t)ri->rodata;
              } else {
                  // Destination is bss
                  dest = (uintptr_t)ri->bss;
              }
          } else if (op == 6) {
              // Destination is mp_fun_table itself
              dest = (uintptr_t)&mp_fun_table;
          } else {
              // Destination is an entry in mp_fun_table
              dest = ((uintptr_t *)&mp_fun_table)[op - 7];
          }
          while (n--) {
              *addr_to_adjust++ += dest;
          }
      }
  }
  
  #endif
  
  STATIC int read_byte(mp_reader_t *reader) {
      return reader->readbyte(reader->data);
  }
  
  STATIC void read_bytes(mp_reader_t *reader, byte *buf, size_t len) {
      while (len-- > 0) {
          *buf++ = reader->readbyte(reader->data);
      }
  }
  
  STATIC size_t read_uint(mp_reader_t *reader) {
      size_t unum = 0;
      for (;;) {
          byte b = reader->readbyte(reader->data);
          unum = (unum << 7) | (b & 0x7f);
          if ((b & 0x80) == 0) {
              break;
          }
      }
      return unum;
  }
  
  STATIC qstr load_qstr(mp_reader_t *reader) {
      size_t len = read_uint(reader);
      if (len & 1) {
          // static qstr
          return len >> 1;
      }
      len >>= 1;
      char *str = m_new(char, len);
      read_bytes(reader, (byte *)str, len);
      read_byte(reader); // read and discard null terminator
      qstr qst = qstr_from_strn(str, len);
      m_del(char, str, len);
      return qst;
  }
  
  STATIC mp_obj_t load_obj(mp_reader_t *reader) {
      byte obj_type = read_byte(reader);
      #if MICROPY_EMIT_MACHINE_CODE
      if (obj_type == MP_PERSISTENT_OBJ_FUN_TABLE) {
          return MP_OBJ_FROM_PTR(&mp_fun_table);
      } else
      #endif
      if (obj_type == MP_PERSISTENT_OBJ_NONE) {
          return mp_const_none;
      } else if (obj_type == MP_PERSISTENT_OBJ_FALSE) {
          return mp_const_false;
      } else if (obj_type == MP_PERSISTENT_OBJ_TRUE) {
          return mp_const_true;
      } else if (obj_type == MP_PERSISTENT_OBJ_ELLIPSIS) {
          return MP_OBJ_FROM_PTR(&mp_const_ellipsis_obj);
      } else {
          size_t len = read_uint(reader);
          if (len == 0 && obj_type == MP_PERSISTENT_OBJ_BYTES) {
              read_byte(reader); // skip null terminator
              return mp_const_empty_bytes;
          } else if (obj_type == MP_PERSISTENT_OBJ_TUPLE) {
              mp_obj_tuple_t *tuple = MP_OBJ_TO_PTR(mp_obj_new_tuple(len, NULL));
              for (size_t i = 0; i < len; ++i) {
                  tuple->items[i] = load_obj(reader);
              }
              return MP_OBJ_FROM_PTR(tuple);
          }
          vstr_t vstr;
          vstr_init_len(&vstr, len);
          read_bytes(reader, (byte *)vstr.buf, len);
          if (obj_type == MP_PERSISTENT_OBJ_STR || obj_type == MP_PERSISTENT_OBJ_BYTES) {
              read_byte(reader); // skip null terminator
              return mp_obj_new_str_from_vstr(obj_type == MP_PERSISTENT_OBJ_STR ? &mp_type_str : &mp_type_bytes, &vstr);
          } else if (obj_type == MP_PERSISTENT_OBJ_INT) {
              return mp_parse_num_integer(vstr.buf, vstr.len, 10, NULL);
          } else {
              assert(obj_type == MP_PERSISTENT_OBJ_FLOAT || obj_type == MP_PERSISTENT_OBJ_COMPLEX);
              return mp_parse_num_decimal(vstr.buf, vstr.len, obj_type == MP_PERSISTENT_OBJ_COMPLEX, false, NULL);
          }
      }
  }
  
  STATIC mp_raw_code_t *load_raw_code(mp_reader_t *reader) {
      // Load function kind and data length
      size_t kind_len = read_uint(reader);
      int kind = (kind_len & 3) + MP_CODE_BYTECODE;
      bool has_children = !!(kind_len & 4);
      size_t fun_data_len = kind_len >> 3;
  
      #if !MICROPY_EMIT_MACHINE_CODE
      if (kind != MP_CODE_BYTECODE) {
          mp_raise_ValueError(MP_ERROR_TEXT("incompatible .mpy file"));
      }
      #endif
  
      uint8_t *fun_data = NULL;
      #if MICROPY_EMIT_MACHINE_CODE
      size_t prelude_offset = 0;
      mp_uint_t native_scope_flags = 0;
      mp_uint_t native_n_pos_args = 0;
      mp_uint_t native_type_sig = 0;
      #endif
  
      if (kind == MP_CODE_BYTECODE) {
          // Allocate memory for the bytecode
          fun_data = m_new(uint8_t, fun_data_len);
          // Load bytecode
          read_bytes(reader, fun_data, fun_data_len);
  
      #if MICROPY_EMIT_MACHINE_CODE
      } else {
          // Allocate memory for native data and load it
          size_t fun_alloc;
          MP_PLAT_ALLOC_EXEC(fun_data_len, (void **)&fun_data, &fun_alloc);
          read_bytes(reader, fun_data, fun_data_len);
  
          if (kind == MP_CODE_NATIVE_PY || kind == MP_CODE_NATIVE_VIPER) {
              // Parse qstr link table and link native code
              size_t n_qstr_link = read_uint(reader);
              for (size_t i = 0; i < n_qstr_link; ++i) {
                  size_t off = read_uint(reader);
                  qstr qst = load_qstr(reader);
                  uint8_t *dest = fun_data + (off >> 2);
                  if ((off & 3) == 0) {
                      // Generic 16-bit link
                      dest[0] = qst & 0xff;
                      dest[1] = (qst >> 8) & 0xff;
                  } else if ((off & 3) == 3) {
                      // Generic, aligned qstr-object link
                      *(mp_obj_t *)dest = MP_OBJ_NEW_QSTR(qst);
                  }
              }
          }
  
          if (kind == MP_CODE_NATIVE_PY) {
              // Read prelude offset within fun_data, and extract scope flags.
              prelude_offset = read_uint(reader);
              const byte *ip = fun_data + prelude_offset;
              MP_BC_PRELUDE_SIG_DECODE(ip);
              native_scope_flags = scope_flags;
          } else {
              // Load basic scope info for viper and asm.
              native_scope_flags = read_uint(reader);
              if (kind == MP_CODE_NATIVE_ASM) {
                  native_n_pos_args = read_uint(reader);
                  native_type_sig = read_uint(reader);
              }
          }
      #endif
      }
  
      size_t n_children = 0;
      mp_raw_code_t **children = NULL;
  
      #if MICROPY_EMIT_MACHINE_CODE
      // Load optional BSS/rodata for viper.
      uint8_t *rodata = NULL;
      uint8_t *bss = NULL;
      if (kind == MP_CODE_NATIVE_VIPER) {
          size_t rodata_size = 0;
          if (native_scope_flags & MP_SCOPE_FLAG_VIPERRODATA) {
              rodata_size = read_uint(reader);
          }
  
          size_t bss_size = 0;
          if (native_scope_flags & MP_SCOPE_FLAG_VIPERBSS) {
              bss_size = read_uint(reader);
          }
  
          if (rodata_size + bss_size != 0) {
              bss_size = (uintptr_t)MP_ALIGN(bss_size, sizeof(uintptr_t));
              uint8_t *data = m_new0(uint8_t, bss_size + rodata_size);
              bss = data;
              rodata = bss + bss_size;
              if (native_scope_flags & MP_SCOPE_FLAG_VIPERRODATA) {
                  read_bytes(reader, rodata, rodata_size);
              }
  
              // Viper code with BSS/rodata should not have any children.
              // Reuse the children pointer to reference the BSS/rodata
              // memory so that it is not reclaimed by the GC.
              assert(!has_children);
              children = (void *)data;
          }
      }
      #endif
  
      // Load children if any.
      if (has_children) {
          n_children = read_uint(reader);
          children = m_new(mp_raw_code_t *, n_children + (kind == MP_CODE_NATIVE_PY));
          for (size_t i = 0; i < n_children; ++i) {
              children[i] = load_raw_code(reader);
          }
      }
  
      // Create raw_code and return it
      mp_raw_code_t *rc = mp_emit_glue_new_raw_code();
      if (kind == MP_CODE_BYTECODE) {
          const byte *ip = fun_data;
          MP_BC_PRELUDE_SIG_DECODE(ip);
          // Assign bytecode to raw code object
          mp_emit_glue_assign_bytecode(rc, fun_data,
              #if MICROPY_PERSISTENT_CODE_SAVE || MICROPY_DEBUG_PRINTERS
              fun_data_len,
              #endif
              children,
              #if MICROPY_PERSISTENT_CODE_SAVE
              n_children,
              #endif
              scope_flags);
  
      #if MICROPY_EMIT_MACHINE_CODE
      } else {
          const uint8_t *prelude_ptr;
          #if MICROPY_EMIT_NATIVE_PRELUDE_SEPARATE_FROM_MACHINE_CODE
          if (kind == MP_CODE_NATIVE_PY) {
              // Executable code cannot be accessed byte-wise on this architecture, so copy
              // the prelude to a separate memory region that is byte-wise readable.
              void *buf = fun_data + prelude_offset;
              size_t n = fun_data_len - prelude_offset;
              prelude_ptr = memcpy(m_new(uint8_t, n), buf, n);
          }
          #endif
  
          // Relocate and commit code to executable address space
          reloc_info_t ri = {reader, rodata, bss};
          #if defined(MP_PLAT_COMMIT_EXEC)
          void *opt_ri = (native_scope_flags & MP_SCOPE_FLAG_VIPERRELOC) ? &ri : NULL;
          fun_data = MP_PLAT_COMMIT_EXEC(fun_data, fun_data_len, opt_ri);
          #else
          if (native_scope_flags & MP_SCOPE_FLAG_VIPERRELOC) {
              #if MICROPY_PERSISTENT_CODE_TRACK_RELOC_CODE
              // If native code needs relocations then it's not guaranteed that a pointer to
              // the head of `buf` (containing the machine code) will be retained for the GC
              // to trace.  This is because native functions can start inside `buf` and so
              // it's possible that the only GC-reachable pointers are pointers inside `buf`.
              // So put this `buf` on a list of reachable root pointers.
              if (MP_STATE_PORT(track_reloc_code_list) == MP_OBJ_NULL) {
                  MP_STATE_PORT(track_reloc_code_list) = mp_obj_new_list(0, NULL);
              }
              mp_obj_list_append(MP_STATE_PORT(track_reloc_code_list), MP_OBJ_FROM_PTR(fun_data));
              #endif
              // Do the relocations.
              mp_native_relocate(&ri, fun_data, (uintptr_t)fun_data);
          }
          #endif
  
          if (kind == MP_CODE_NATIVE_PY) {
              #if !MICROPY_EMIT_NATIVE_PRELUDE_SEPARATE_FROM_MACHINE_CODE
              prelude_ptr = fun_data + prelude_offset;
              #endif
              if (n_children == 0) {
                  children = (void *)prelude_ptr;
              } else {
                  children[n_children] = (void *)prelude_ptr;
              }
          }
  
          // Assign native code to raw code object
          mp_emit_glue_assign_native(rc, kind,
              fun_data, fun_data_len,
              children,
              #if MICROPY_PERSISTENT_CODE_SAVE
              n_children,
              prelude_offset,
              #endif
              native_scope_flags, native_n_pos_args, native_type_sig
              );
      #endif
      }
      return rc;
  }
  
  mp_compiled_module_t mp_raw_code_load(mp_reader_t *reader, mp_module_context_t *context) {
      byte header[4];
      read_bytes(reader, header, sizeof(header));
      if (header[0] != 'M'
          || header[1] != MPY_VERSION
          || MPY_FEATURE_DECODE_FLAGS(header[2]) != MPY_FEATURE_FLAGS
          || header[3] > MP_SMALL_INT_BITS) {
          mp_raise_ValueError(MP_ERROR_TEXT("incompatible .mpy file"));
      }
      if (MPY_FEATURE_DECODE_ARCH(header[2]) != MP_NATIVE_ARCH_NONE) {
          byte arch = MPY_FEATURE_DECODE_ARCH(header[2]);
          if (!MPY_FEATURE_ARCH_TEST(arch)) {
              mp_raise_ValueError(MP_ERROR_TEXT("incompatible .mpy arch"));
          }
      }
  
      size_t n_qstr = read_uint(reader);
      size_t n_obj = read_uint(reader);
      mp_module_context_alloc_tables(context, n_qstr, n_obj);
  
      // Load qstrs.
      for (size_t i = 0; i < n_qstr; ++i) {
          context->constants.qstr_table[i] = load_qstr(reader);
      }
  
      // Load constant objects.
      for (size_t i = 0; i < n_obj; ++i) {
          context->constants.obj_table[i] = load_obj(reader);
      }
  
      // Load top-level module.
      mp_compiled_module_t cm2;
      cm2.rc = load_raw_code(reader);
      cm2.context = context;
  
      #if MICROPY_PERSISTENT_CODE_SAVE
      cm2.has_native = MPY_FEATURE_DECODE_ARCH(header[2]) != MP_NATIVE_ARCH_NONE;
      cm2.n_qstr = n_qstr;
      cm2.n_obj = n_obj;
      #endif
  
      reader->close(reader->data);
  
      return cm2;
  }
  
  mp_compiled_module_t mp_raw_code_load_mem(const byte *buf, size_t len, mp_module_context_t *context) {
      mp_reader_t reader;
      mp_reader_new_mem(&reader, buf, len, 0);
      return mp_raw_code_load(&reader, context);
  }
  
  #if MICROPY_HAS_FILE_READER
  
  mp_compiled_module_t mp_raw_code_load_file(const char *filename, mp_module_context_t *context) {
      mp_reader_t reader;
      mp_reader_new_file(&reader, filename);
      return mp_raw_code_load(&reader, context);
  }
  
  #endif // MICROPY_HAS_FILE_READER
  
  #endif // MICROPY_PERSISTENT_CODE_LOAD
  
  #if MICROPY_PERSISTENT_CODE_SAVE
  
  #include "py/objstr.h"
  
  STATIC void mp_print_bytes(mp_print_t *print, const byte *data, size_t len) {
      print->print_strn(print->data, (const char *)data, len);
  }
  
  #define BYTES_FOR_INT ((MP_BYTES_PER_OBJ_WORD * 8 + 6) / 7)
  STATIC void mp_print_uint(mp_print_t *print, size_t n) {
      byte buf[BYTES_FOR_INT];
      byte *p = buf + sizeof(buf);
      *--p = n & 0x7f;
      n >>= 7;
      for (; n != 0; n >>= 7) {
          *--p = 0x80 | (n & 0x7f);
      }
      print->print_strn(print->data, (char *)p, buf + sizeof(buf) - p);
  }
  
  STATIC void save_qstr(mp_print_t *print, qstr qst) {
      if (qst <= QSTR_LAST_STATIC) {
          // encode static qstr
          mp_print_uint(print, qst << 1 | 1);
          return;
      }
      size_t len;
      const byte *str = qstr_data(qst, &len);
      mp_print_uint(print, len << 1);
      mp_print_bytes(print, str, len + 1); // +1 to store null terminator
  }
  
  STATIC void save_obj(mp_print_t *print, mp_obj_t o) {
      #if MICROPY_EMIT_MACHINE_CODE
      if (o == MP_OBJ_FROM_PTR(&mp_fun_table)) {
          byte obj_type = MP_PERSISTENT_OBJ_FUN_TABLE;
          mp_print_bytes(print, &obj_type, 1);
      } else
      #endif
      if (mp_obj_is_str_or_bytes(o)) {
          byte obj_type;
          if (mp_obj_is_str(o)) {
              obj_type = MP_PERSISTENT_OBJ_STR;
          } else {
              obj_type = MP_PERSISTENT_OBJ_BYTES;
          }
          size_t len;
          const char *str = mp_obj_str_get_data(o, &len);
          mp_print_bytes(print, &obj_type, 1);
          mp_print_uint(print, len);
          mp_print_bytes(print, (const byte *)str, len + 1); // +1 to store null terminator
      } else if (o == mp_const_none) {
          byte obj_type = MP_PERSISTENT_OBJ_NONE;
          mp_print_bytes(print, &obj_type, 1);
      } else if (o == mp_const_false) {
          byte obj_type = MP_PERSISTENT_OBJ_FALSE;
          mp_print_bytes(print, &obj_type, 1);
      } else if (o == mp_const_true) {
          byte obj_type = MP_PERSISTENT_OBJ_TRUE;
          mp_print_bytes(print, &obj_type, 1);
      } else if (MP_OBJ_TO_PTR(o) == &mp_const_ellipsis_obj) {
          byte obj_type = MP_PERSISTENT_OBJ_ELLIPSIS;
          mp_print_bytes(print, &obj_type, 1);
      } else if (mp_obj_is_type(o, &mp_type_tuple)) {
          size_t len;
          mp_obj_t *items;
          mp_obj_tuple_get(o, &len, &items);
          byte obj_type = MP_PERSISTENT_OBJ_TUPLE;
          mp_print_bytes(print, &obj_type, 1);
          mp_print_uint(print, len);
          for (size_t i = 0; i < len; ++i) {
              save_obj(print, items[i]);
          }
      } else {
          // we save numbers using a simplistic text representation
          // TODO could be improved
          byte obj_type;
          if (mp_obj_is_int(o)) {
              obj_type = MP_PERSISTENT_OBJ_INT;
          #if MICROPY_PY_BUILTINS_COMPLEX
          } else if (mp_obj_is_type(o, &mp_type_complex)) {
              obj_type = MP_PERSISTENT_OBJ_COMPLEX;
          #endif
          } else {
              assert(mp_obj_is_float(o));
              obj_type = MP_PERSISTENT_OBJ_FLOAT;
          }
          vstr_t vstr;
          mp_print_t pr;
          vstr_init_print(&vstr, 10, &pr);
          mp_obj_print_helper(&pr, o, PRINT_REPR);
          mp_print_bytes(print, &obj_type, 1);
          mp_print_uint(print, vstr.len);
          mp_print_bytes(print, (const byte *)vstr.buf, vstr.len);
          vstr_clear(&vstr);
      }
  }
  
  STATIC void save_raw_code(mp_print_t *print, const mp_raw_code_t *rc) {
      // Save function kind and data length
      mp_print_uint(print, (rc->fun_data_len << 3) | ((rc->n_children != 0) << 2) | (rc->kind - MP_CODE_BYTECODE));
  
      // Save function code.
      mp_print_bytes(print, rc->fun_data, rc->fun_data_len);
  
      #if MICROPY_EMIT_MACHINE_CODE
      if (rc->kind == MP_CODE_NATIVE_PY || rc->kind == MP_CODE_NATIVE_VIPER) {
          // Save qstr link table for native code
          mp_print_uint(print, 0);
      }
  
      if (rc->kind == MP_CODE_NATIVE_PY) {
          // Save prelude size
          mp_print_uint(print, rc->prelude_offset);
      } else if (rc->kind == MP_CODE_NATIVE_VIPER || rc->kind == MP_CODE_NATIVE_ASM) {
          // Save basic scope info for viper and asm
          mp_print_uint(print, rc->scope_flags & MP_SCOPE_FLAG_ALL_SIG);
          if (rc->kind == MP_CODE_NATIVE_ASM) {
              mp_print_uint(print, rc->n_pos_args);
              mp_print_uint(print, rc->type_sig);
          }
      }
      #endif
  
      if (rc->n_children) {
          mp_print_uint(print, rc->n_children);
          for (size_t i = 0; i < rc->n_children; ++i) {
              save_raw_code(print, rc->children[i]);
          }
      }
  }
  
  void mp_raw_code_save(mp_compiled_module_t *cm, mp_print_t *print) {
      // header contains:
      //  byte  'M'
      //  byte  version
      //  byte  feature flags
      //  byte  number of bits in a small int
      byte header[4] = {
          'M',
          MPY_VERSION,
          MPY_FEATURE_ENCODE_FLAGS(MPY_FEATURE_FLAGS_DYNAMIC),
          #if MICROPY_DYNAMIC_COMPILER
          mp_dynamic_compiler.small_int_bits,
          #else
          MP_SMALL_INT_BITS,
          #endif
      };
      if (cm->has_native) {
          header[2] |= MPY_FEATURE_ENCODE_ARCH(MPY_FEATURE_ARCH_DYNAMIC);
      }
      mp_print_bytes(print, header, sizeof(header));
  
      // Number of entries in constant table.
      mp_print_uint(print, cm->n_qstr);
      mp_print_uint(print, cm->n_obj);
  
      // Save qstrs.
      for (size_t i = 0; i < cm->n_qstr; ++i) {
          save_qstr(print, cm->context->constants.qstr_table[i]);
      }
  
      // Save constant objects.
      for (size_t i = 0; i < cm->n_obj; ++i) {
          save_obj(print, (mp_obj_t)cm->context->constants.obj_table[i]);
      }
  
      // Save outer raw code, which will save all its child raw codes.
      save_raw_code(print, cm->rc);
  }
  
  #if MICROPY_PERSISTENT_CODE_SAVE_FILE
  
  #include <unistd.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  
  STATIC void fd_print_strn(void *env, const char *str, size_t len) {
      int fd = (intptr_t)env;
      MP_THREAD_GIL_EXIT();
      ssize_t ret = write(fd, str, len);
      MP_THREAD_GIL_ENTER();
      (void)ret;
  }
  
  void mp_raw_code_save_file(mp_compiled_module_t *cm, const char *filename) {
      MP_THREAD_GIL_EXIT();
      int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0644);
      MP_THREAD_GIL_ENTER();
      mp_print_t fd_print = {(void *)(intptr_t)fd, fd_print_strn};
      mp_raw_code_save(cm, &fd_print);
      MP_THREAD_GIL_EXIT();
      close(fd);
      MP_THREAD_GIL_ENTER();
  }
  
  #endif // MICROPY_PERSISTENT_CODE_SAVE_FILE
  
  #endif // MICROPY_PERSISTENT_CODE_SAVE
  