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8966380ef9
Make build_symbol_table.py output statistics on the symbol table it builds, and emit warnings for zero-length symbols. Also added lengths to several functions defined in asm that this uncovered.
87 lines
2.2 KiB
Python
Executable File
87 lines
2.2 KiB
Python
Executable File
#!/usr/bin/env python3
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#
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# Generate the jsix style symbol table. The format in memory of this table
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# is as follows:
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#
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# <num_entires> : 8 bytes
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# <index> : 24 * N bytes
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# <name data> : variable
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#
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# Each index entry has the format
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# <symbol address> : 8 bytes
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# <symbol size> : 8 bytes
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# <offset of name> : 8 bytes
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#
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# Name offsets are from the start of the symbol table as a whole. (ie,
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# where <num_entries> is located.)
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import re
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sym_re = re.compile(r'([0-9a-fA-F]{16}) ([0-9a-fA-F]{16} )?[tTvVwW] (.*)')
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def parse_syms(infile):
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"""Take the output of the `nm` command, and parse it into a tuple
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representing the symbols in the text segment of the binary. Returns
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a list of (address, symbol_name)."""
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syms = []
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for line in sys.stdin:
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match = sym_re.match(line)
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if not match: continue
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addr = int(match.group(1), base=16)
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size = int(match.group(2) or "0", base=16)
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name = match.group(3)
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if size == 0:
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if not "." in name:
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print(f"SYMBOL WARNING: zero size for symbol {name}")
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continue
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syms.append([addr, size, name, 0])
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return syms
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def write_table(syms, outfile):
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"""Write the given symbol table as generated by parse_syms()
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to the outfile, index first, and then name character data."""
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import struct
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outfile.write(struct.pack("@Q", len(syms)))
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index_pos = outfile.tell()
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outfile.seek(struct.calcsize("@QQQ") * len(syms), 1)
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nul = b'\0'
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for s in syms:
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s[3] = outfile.tell()
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outfile.write(s[2].encode('utf-8'))
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outfile.write(nul)
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outfile.seek(index_pos)
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for s in syms:
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addr = s[0]
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size = s[1]
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pos = s[3]
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outfile.write(struct.pack("@QQQ", addr, size, pos))
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return len(syms)
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if __name__ == "__main__":
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import sys
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if len(sys.argv) != 2:
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print(f"Usage: nm -n -S --demangle | {sys.argv[0]} <output>")
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sys.exit(1)
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syms = 0
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size = 0
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with open(sys.argv[1], "wb") as outfile:
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syms = write_table(parse_syms(sys.stdin), outfile)
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outfile.seek(0, 2)
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size = outfile.tell()
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print(f"Wrote {syms} symbols ({size/1024:.1f} KiB) to {sys.argv[1]}.")
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