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1"""Generate targets for computed goto dispatch
2Reads the instruction definitions from bytecodes.c.
3Writes the table to opcode_targets.h by default.
4"""
5
6import argparse
7
8from analyzer import (
9    Analysis,
10    analyze_files,
11)
12from generators_common import (
13    DEFAULT_INPUT,
14    ROOT,
15)
16from cwriter import CWriter
17from typing import TextIO
18
19
20DEFAULT_OUTPUT = ROOT / "Python/opcode_targets.h"
21
22
23def write_opcode_targets(analysis: Analysis, out: CWriter) -> None:
24    """Write header file that defines the jump target table"""
25    targets = ["&&_unknown_opcode,\n"] * 256
26    for name, op in analysis.opmap.items():
27        if op < 256:
28            targets[op] = f"&&TARGET_{name},\n"
29    out.emit("static void *opcode_targets[256] = {\n")
30    for target in targets:
31        out.emit(target)
32    out.emit("};\n")
33
34arg_parser = argparse.ArgumentParser(
35    description="Generate the file with dispatch targets.",
36    formatter_class=argparse.ArgumentDefaultsHelpFormatter,
37)
38
39arg_parser.add_argument(
40    "-o", "--output", type=str, help="Generated code", default=DEFAULT_OUTPUT
41)
42
43arg_parser.add_argument(
44    "input", nargs=argparse.REMAINDER, help="Instruction definition file(s)"
45)
46
47if __name__ == "__main__":
48    args = arg_parser.parse_args()
49    if len(args.input) == 0:
50        args.input.append(DEFAULT_INPUT)
51    data = analyze_files(args.input)
52    with open(args.output, "w") as outfile:
53        out = CWriter(outfile, 0, False)
54        write_opcode_targets(data, out)
55