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132 lines
4.3 KiB
Python
132 lines
4.3 KiB
Python
"""Generate the main interpreter switch."""
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# Write the cases to generated_cases.c.h, which is #included in ceval.c.
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# TODO: Reuse C generation framework from deepfreeze.py?
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import argparse
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import io
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import re
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import sys
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import parser
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from parser import InstDef
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arg_parser = argparse.ArgumentParser()
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arg_parser.add_argument("-i", "--input", type=str, default="Python/bytecodes.c")
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arg_parser.add_argument("-o", "--output", type=str, default="Python/generated_cases.c.h")
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arg_parser.add_argument("-c", "--compare", action="store_true")
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arg_parser.add_argument("-q", "--quiet", action="store_true")
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def eopen(filename: str, mode: str = "r"):
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if filename == "-":
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if "r" in mode:
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return sys.stdin
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else:
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return sys.stdout
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return open(filename, mode)
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def parse_cases(src: str, filename: str|None = None) -> tuple[list[InstDef], list[parser.Family]]:
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psr = parser.Parser(src, filename=filename)
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instrs: list[InstDef] = []
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families: list[parser.Family] = []
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while not psr.eof():
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if inst := psr.inst_def():
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assert inst.block
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instrs.append(InstDef(inst.name, inst.inputs, inst.outputs, inst.block))
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elif fam := psr.family_def():
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families.append(fam)
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else:
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raise psr.make_syntax_error(f"Unexpected token")
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return instrs, families
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def always_exits(block: parser.Block) -> bool:
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text = block.text
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lines = text.splitlines()
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while lines and not lines[-1].strip():
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lines.pop()
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if not lines or lines[-1].strip() != "}":
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return False
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lines.pop()
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if not lines:
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return False
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line = lines.pop().rstrip()
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# Indent must match exactly (TODO: Do something better)
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if line[:12] != " "*12:
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return False
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line = line[12:]
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return line.startswith(("goto ", "return ", "DISPATCH", "GO_TO_", "Py_UNREACHABLE()"))
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def write_cases(f: io.TextIOBase, instrs: list[InstDef]):
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predictions = set()
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for inst in instrs:
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for target in re.findall(r"(?:PREDICT|GO_TO_INSTRUCTION)\((\w+)\)", inst.block.text):
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predictions.add(target)
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indent = " "
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f.write("// This file is generated by Tools/scripts/generate_cases.py\n")
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f.write("// Do not edit!\n")
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for instr in instrs:
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assert isinstance(instr, InstDef)
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f.write(f"\n{indent}TARGET({instr.name}) {{\n")
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if instr.name in predictions:
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f.write(f"{indent} PREDICTED({instr.name});\n")
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# input = ", ".join(instr.inputs)
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# output = ", ".join(instr.outputs)
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# f.write(f"{indent} // {input} -- {output}\n")
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assert instr.block
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blocklines = instr.block.text.splitlines(True)
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# Remove blank lines from ends
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while blocklines and not blocklines[0].strip():
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blocklines.pop(0)
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while blocklines and not blocklines[-1].strip():
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blocklines.pop()
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# Remove leading '{' and trailing '}'
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assert blocklines and blocklines[0].strip() == "{"
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assert blocklines and blocklines[-1].strip() == "}"
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blocklines.pop()
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blocklines.pop(0)
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# Remove trailing blank lines
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while blocklines and not blocklines[-1].strip():
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blocklines.pop()
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# Write the body
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for line in blocklines:
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f.write(line)
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assert instr.block
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if not always_exits(instr.block):
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f.write(f"{indent} DISPATCH();\n")
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# Write trailing '}'
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f.write(f"{indent}}}\n")
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def main():
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args = arg_parser.parse_args()
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with eopen(args.input) as f:
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srclines = f.read().splitlines()
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begin = srclines.index("// BEGIN BYTECODES //")
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end = srclines.index("// END BYTECODES //")
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src = "\n".join(srclines[begin+1 : end])
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instrs, families = parse_cases(src, filename=args.input)
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ninstrs = nfamilies = 0
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if not args.quiet:
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ninstrs = len(instrs)
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nfamilies = len(families)
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print(
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f"Read {ninstrs} instructions "
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f"and {nfamilies} families from {args.input}",
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file=sys.stderr,
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)
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with eopen(args.output, "w") as f:
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write_cases(f, instrs)
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if not args.quiet:
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print(
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f"Wrote {ninstrs} instructions to {args.output}",
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file=sys.stderr,
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)
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if __name__ == "__main__":
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main()
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