pebble/tools/js/dump_snapshot_literals.py
2025-01-27 11:38:16 -08:00

101 lines
3.6 KiB
Python
Executable file

#! /usr/bin/env python
# Copyright 2024 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import sys
import struct
ROCKY_HEADER_SIZE = 8
ROCKY_HEADER_FMT = "4sB3x"
JERRY_HEADER_SIZE = 16
JERRY_HEADER_FMT = "<4I"
LIT_TABLE_HEADER_SIZE = 8
LIT_TABLE_HEADER_FMT = "<2I"
LIT_STRING_HEADER_SIZE = 2
LIT_STRING_HEADER_FMT = "<H"
def _get_aligned_literal_length(length):
LITERAL_ALIGNMENT = (1 << 2)
return ((length) + (LITERAL_ALIGNMENT - 1)) & ~(LITERAL_ALIGNMENT - 1)
def main(snapshot_path):
with open(snapshot_path, 'rb') as fin:
# TODO: This should be generalized to a prefix string, not a Rocky header
rocky_header = struct.unpack(ROCKY_HEADER_FMT, fin.read(ROCKY_HEADER_SIZE))
print "Rocky Header"
print " Signature: {}".format(rocky_header[0])
print " Version: 0x{:02x}".format(rocky_header[1])
print
jerry_header = struct.unpack(JERRY_HEADER_FMT, fin.read(JERRY_HEADER_SIZE))
print "Jerry Header"
print " Version: {}".format(jerry_header[0])
print " lit_table_offset: {}".format(jerry_header[1])
print " lit_table_size: {}".format(jerry_header[2])
print " is_run_global: {}".format(jerry_header[3])
print
fin.seek(jerry_header[1] + ROCKY_HEADER_SIZE, 0) # position to beginning of literal table
lit_header = struct.unpack(LIT_TABLE_HEADER_FMT, fin.read(LIT_TABLE_HEADER_SIZE))
lit_string_count = lit_header[0]
lit_number_count = lit_header[1]
print "Literal Header"
print " String Count: {}".format(lit_string_count)
print " Number Count: {}".format(lit_number_count)
print
# Now dump the literal tables
offset = 0
for i in xrange(lit_string_count):
length = struct.unpack(LIT_STRING_HEADER_FMT, fin.read(LIT_STRING_HEADER_SIZE))[0]
aligned_length = _get_aligned_literal_length(2 + length)
s = struct.unpack("{}s".format(length), fin.read(length))[0]
print "0x{:08x}: String: '{}'".format(offset, s)
move = aligned_length - length - 2 # - 2 since the header was already read
if move > 0:
fin.seek(move, 1)
offset += aligned_length
remaining_length = jerry_header[2] - offset - LIT_TABLE_HEADER_SIZE
number_length = remaining_length / float(lit_number_count)
if not number_length.is_integer():
print "Invalid offset for start of number literals"
return 1
number_length = int(number_length)
for i in xrange(lit_number_count):
length = number_length
aligned_length = _get_aligned_literal_length(length)
n = struct.unpack("d" if length == 8 else "f", fin.read(length))[0]
print "0x{:08x}: Number: {}".format(offset, n)
move = aligned_length - length
if move > 0:
fin.seek(move, 1)
offset += aligned_length
print "Numbers are {}-bit".format(number_length * 8)
return 0
if __name__ == "__main__":
rc = main(sys.argv[1])
sys.exit(rc)