Files
jsix/scripts/build_symbol_table.py
Justin C. Miller a0d165c79b [scripts] Ignore demangle errors building sym table
For some reason, cxxfilt fails to demangle some names on some systems.
Instead of failing the build process, just skip those symbols.
2021-01-18 13:49:10 -08:00

76 lines
1.9 KiB
Python
Executable File

#!/usr/bin/env python3
#
# Generate the jsix style symbol table. The format in memory of this table
# is as follows:
#
# <num_entires> : 8 bytes
# <index> : 16 * N bytes
# <name data> : variable
#
# Each index entry has the format
# <symbol address> : 8 bytes
# <offset of name> : 8 bytes
#
# Name offsets are from the start of the symbol table as a whole. (ie,
# where <num_entries> is located.)
def parse_syms(infile):
"""Take the output of the `nm` command, and parse it into a tuple
representing the symbols in the text segment of the binary. Returns
a list of (address, symbol_name)."""
from cxxfilt import demangle, InvalidName
syms = []
for line in sys.stdin:
addr, t, mangled = line.split()
if t not in "tTvVwW": continue
try:
name = demangle(mangled)
except InvalidName:
continue
addr = int(addr, base=16)
syms.append((addr, name))
return sorted(syms)
def write_table(syms, outfile):
"""Write the given symbol table as generated by parse_syms()
to the outfile, index first, and then name character data."""
import struct
outfile.write(struct.pack("@Q", len(syms)))
index_pos = outfile.tell()
outfile.seek(struct.calcsize("@QQ") * len(syms), 1)
nul = b'\0'
positions = {}
for s in syms:
addr, name = s
positions[addr] = outfile.tell()
data = name.encode('utf-8')
outfile.write(name.encode('utf-8'))
outfile.write(nul)
outfile.seek(index_pos)
for s in syms:
addr = s[0]
pos = positions[addr]
outfile.write(struct.pack("@QQ", addr, pos))
if __name__ == "__main__":
import sys
if len(sys.argv) != 2:
print(f"Usage: {sys.argv[0]} <output>")
sys.exit(1)
outfile = open(sys.argv[1], "wb")
write_table(parse_syms(sys.stdin), outfile)