mirror of https://github.com/python/cpython
670 lines
24 KiB
Python
670 lines
24 KiB
Python
"""Generate the main interpreter switch.
|
|
|
|
Reads the instruction definitions from bytecodes.c.
|
|
Writes the cases to generated_cases.c.h, which is #included in ceval.c.
|
|
"""
|
|
|
|
import argparse
|
|
import contextlib
|
|
import dataclasses
|
|
import os
|
|
import re
|
|
import sys
|
|
import typing
|
|
|
|
import parser
|
|
|
|
DEFAULT_INPUT = os.path.relpath(
|
|
os.path.join(os.path.dirname(__file__), "../../Python/bytecodes.c")
|
|
)
|
|
DEFAULT_OUTPUT = os.path.relpath(
|
|
os.path.join(os.path.dirname(__file__), "../../Python/generated_cases.c.h")
|
|
)
|
|
BEGIN_MARKER = "// BEGIN BYTECODES //"
|
|
END_MARKER = "// END BYTECODES //"
|
|
RE_PREDICTED = r"(?s)(?:PREDICT\(|GO_TO_INSTRUCTION\(|DEOPT_IF\(.*?,\s*)(\w+)\);"
|
|
UNUSED = "unused"
|
|
BITS_PER_CODE_UNIT = 16
|
|
|
|
arg_parser = argparse.ArgumentParser(
|
|
description="Generate the code for the interpreter switch.",
|
|
formatter_class=argparse.ArgumentDefaultsHelpFormatter,
|
|
)
|
|
arg_parser.add_argument(
|
|
"-i", "--input", type=str, help="Instruction definitions", default=DEFAULT_INPUT
|
|
)
|
|
arg_parser.add_argument(
|
|
"-o", "--output", type=str, help="Generated code", default=DEFAULT_OUTPUT
|
|
)
|
|
|
|
|
|
class Formatter:
|
|
"""Wraps an output stream with the ability to indent etc."""
|
|
|
|
stream: typing.TextIO
|
|
prefix: str
|
|
|
|
def __init__(self, stream: typing.TextIO, indent: int) -> None:
|
|
self.stream = stream
|
|
self.prefix = " " * indent
|
|
|
|
def write_raw(self, s: str) -> None:
|
|
self.stream.write(s)
|
|
|
|
def emit(self, arg: str) -> None:
|
|
if arg:
|
|
self.write_raw(f"{self.prefix}{arg}\n")
|
|
else:
|
|
self.write_raw("\n")
|
|
|
|
@contextlib.contextmanager
|
|
def indent(self):
|
|
self.prefix += " "
|
|
yield
|
|
self.prefix = self.prefix[:-4]
|
|
|
|
@contextlib.contextmanager
|
|
def block(self, head: str):
|
|
if head:
|
|
self.emit(head + " {")
|
|
else:
|
|
self.emit("{")
|
|
with self.indent():
|
|
yield
|
|
self.emit("}")
|
|
|
|
|
|
@dataclasses.dataclass
|
|
class Instruction:
|
|
"""An instruction with additional data and code."""
|
|
|
|
# Parts of the underlying instruction definition
|
|
inst: parser.InstDef
|
|
kind: typing.Literal["inst", "op"]
|
|
name: str
|
|
block: parser.Block
|
|
|
|
# Computed by constructor
|
|
always_exits: bool
|
|
cache_offset: int
|
|
cache_effects: list[parser.CacheEffect]
|
|
input_effects: list[parser.StackEffect]
|
|
output_effects: list[parser.StackEffect]
|
|
|
|
# Set later
|
|
family: parser.Family | None = None
|
|
predicted: bool = False
|
|
|
|
def __init__(self, inst: parser.InstDef):
|
|
self.inst = inst
|
|
self.kind = inst.kind
|
|
self.name = inst.name
|
|
self.block = inst.block
|
|
self.always_exits = always_exits(self.block)
|
|
self.cache_effects = [
|
|
effect for effect in inst.inputs if isinstance(effect, parser.CacheEffect)
|
|
]
|
|
self.cache_offset = sum(c.size for c in self.cache_effects)
|
|
self.input_effects = [
|
|
effect for effect in inst.inputs if isinstance(effect, parser.StackEffect)
|
|
]
|
|
self.output_effects = inst.outputs # For consistency/completeness
|
|
|
|
def write(self, out: Formatter) -> None:
|
|
"""Write one instruction, sans prologue and epilogue."""
|
|
# Write a static assertion that a family's cache size is correct
|
|
if family := self.family:
|
|
if self.name == family.members[0]:
|
|
if cache_size := family.size:
|
|
out.emit(
|
|
f"static_assert({cache_size} == "
|
|
f'{self.cache_offset}, "incorrect cache size");'
|
|
)
|
|
|
|
# Write input stack effect variable declarations and initializations
|
|
for i, seffect in enumerate(reversed(self.input_effects), 1):
|
|
if seffect.name != UNUSED:
|
|
out.emit(f"PyObject *{seffect.name} = PEEK({i});")
|
|
|
|
# Write output stack effect variable declarations
|
|
input_names = {seffect.name for seffect in self.input_effects}
|
|
input_names.add(UNUSED)
|
|
for seffect in self.output_effects:
|
|
if seffect.name not in input_names:
|
|
out.emit(f"PyObject *{seffect.name};")
|
|
|
|
self.write_body(out, 0)
|
|
|
|
# Skip the rest if the block always exits
|
|
if always_exits(self.block):
|
|
return
|
|
|
|
# Write net stack growth/shrinkage
|
|
diff = len(self.output_effects) - len(self.input_effects)
|
|
if diff > 0:
|
|
out.emit(f"STACK_GROW({diff});")
|
|
elif diff < 0:
|
|
out.emit(f"STACK_SHRINK({-diff});")
|
|
|
|
# Write output stack effect assignments
|
|
unmoved_names = {UNUSED}
|
|
for ieffect, oeffect in zip(self.input_effects, self.output_effects):
|
|
if ieffect.name == oeffect.name:
|
|
unmoved_names.add(ieffect.name)
|
|
for i, seffect in enumerate(reversed(self.output_effects)):
|
|
if seffect.name not in unmoved_names:
|
|
out.emit(f"POKE({i+1}, {seffect.name});")
|
|
|
|
# Write cache effect
|
|
if self.cache_offset:
|
|
out.emit(f"next_instr += {self.cache_offset};")
|
|
|
|
def write_body(self, out: Formatter, dedent: int, cache_adjust: int = 0) -> None:
|
|
"""Write the instruction body."""
|
|
# Write cache effect variable declarations and initializations
|
|
cache_offset = cache_adjust
|
|
for ceffect in self.cache_effects:
|
|
if ceffect.name != UNUSED:
|
|
bits = ceffect.size * BITS_PER_CODE_UNIT
|
|
if bits == 64:
|
|
# NOTE: We assume that 64-bit data in the cache
|
|
# is always an object pointer.
|
|
# If this becomes false, we need a way to specify
|
|
# syntactically what type the cache data is.
|
|
type = "PyObject *"
|
|
func = "read_obj"
|
|
else:
|
|
type = f"uint{bits}_t "
|
|
func = f"read_u{bits}"
|
|
out.emit(f"{type}{ceffect.name} = {func}(next_instr + {cache_offset});")
|
|
cache_offset += ceffect.size
|
|
assert cache_offset == self.cache_offset + cache_adjust
|
|
|
|
# Get lines of text with proper dedent
|
|
blocklines = self.block.to_text(dedent=dedent).splitlines(True)
|
|
|
|
# Remove blank lines from both ends
|
|
while blocklines and not blocklines[0].strip():
|
|
blocklines.pop(0)
|
|
while blocklines and not blocklines[-1].strip():
|
|
blocklines.pop()
|
|
|
|
# Remove leading and trailing braces
|
|
assert blocklines and blocklines[0].strip() == "{"
|
|
assert blocklines and blocklines[-1].strip() == "}"
|
|
blocklines.pop()
|
|
blocklines.pop(0)
|
|
|
|
# Remove trailing blank lines
|
|
while blocklines and not blocklines[-1].strip():
|
|
blocklines.pop()
|
|
|
|
# Write the body, substituting a goto for ERROR_IF()
|
|
for line in blocklines:
|
|
if m := re.match(r"(\s*)ERROR_IF\((.+), (\w+)\);\s*$", line):
|
|
space, cond, label = m.groups()
|
|
# ERROR_IF() must pop the inputs from the stack.
|
|
# The code block is responsible for DECREF()ing them.
|
|
# NOTE: If the label doesn't exist, just add it to ceval.c.
|
|
ninputs = len(self.input_effects)
|
|
# Don't pop common input/output effects at the bottom!
|
|
# These aren't DECREF'ed so they can stay.
|
|
for ieff, oeff in zip(self.input_effects, self.output_effects):
|
|
if ieff.name == oeff.name:
|
|
ninputs -= 1
|
|
else:
|
|
break
|
|
if ninputs:
|
|
out.write_raw(f"{space}if ({cond}) goto pop_{ninputs}_{label};\n")
|
|
else:
|
|
out.write_raw(f"{space}if ({cond}) goto {label};\n")
|
|
else:
|
|
out.write_raw(line)
|
|
|
|
|
|
InstructionOrCacheEffect = Instruction | parser.CacheEffect
|
|
|
|
|
|
@dataclasses.dataclass
|
|
class Component:
|
|
instr: Instruction
|
|
input_mapping: dict[str, parser.StackEffect]
|
|
output_mapping: dict[str, parser.StackEffect]
|
|
|
|
def write_body(self, out: Formatter, cache_adjust: int) -> None:
|
|
with out.block(""):
|
|
for var, ieffect in self.input_mapping.items():
|
|
out.emit(f"PyObject *{ieffect.name} = {var};")
|
|
for oeffect in self.output_mapping.values():
|
|
out.emit(f"PyObject *{oeffect.name};")
|
|
self.instr.write_body(out, dedent=-4, cache_adjust=cache_adjust)
|
|
for var, oeffect in self.output_mapping.items():
|
|
out.emit(f"{var} = {oeffect.name};")
|
|
|
|
|
|
# TODO: Use a common base class for {Super,Macro}Instruction
|
|
|
|
|
|
@dataclasses.dataclass
|
|
class SuperOrMacroInstruction:
|
|
"""Common fields for super- and macro instructions."""
|
|
|
|
name: str
|
|
stack: list[str]
|
|
initial_sp: int
|
|
final_sp: int
|
|
|
|
|
|
@dataclasses.dataclass
|
|
class SuperInstruction(SuperOrMacroInstruction):
|
|
"""A super-instruction."""
|
|
|
|
super: parser.Super
|
|
parts: list[Component]
|
|
|
|
|
|
@dataclasses.dataclass
|
|
class MacroInstruction(SuperOrMacroInstruction):
|
|
"""A macro instruction."""
|
|
|
|
macro: parser.Macro
|
|
parts: list[Component | parser.CacheEffect]
|
|
|
|
|
|
class Analyzer:
|
|
"""Parse input, analyze it, and write to output."""
|
|
|
|
filename: str
|
|
output_filename: str
|
|
src: str
|
|
errors: int = 0
|
|
|
|
def __init__(self, filename: str, output_filename: str):
|
|
"""Read the input file."""
|
|
self.filename = filename
|
|
self.output_filename = output_filename
|
|
with open(filename) as f:
|
|
self.src = f.read()
|
|
|
|
def error(self, msg: str, node: parser.Node) -> None:
|
|
lineno = 0
|
|
if context := node.context:
|
|
# Use line number of first non-comment in the node
|
|
for token in context.owner.tokens[context.begin : context.end]:
|
|
lineno = token.line
|
|
if token.kind != "COMMENT":
|
|
break
|
|
print(f"{self.filename}:{lineno}: {msg}", file=sys.stderr)
|
|
self.errors += 1
|
|
|
|
instrs: dict[str, Instruction] # Includes ops
|
|
supers: dict[str, parser.Super]
|
|
super_instrs: dict[str, SuperInstruction]
|
|
macros: dict[str, parser.Macro]
|
|
macro_instrs: dict[str, MacroInstruction]
|
|
families: dict[str, parser.Family]
|
|
|
|
def parse(self) -> None:
|
|
"""Parse the source text.
|
|
|
|
We only want the parser to see the stuff between the
|
|
begin and end markers.
|
|
"""
|
|
psr = parser.Parser(self.src, filename=self.filename)
|
|
|
|
# Skip until begin marker
|
|
while tkn := psr.next(raw=True):
|
|
if tkn.text == BEGIN_MARKER:
|
|
break
|
|
else:
|
|
raise psr.make_syntax_error(
|
|
f"Couldn't find {BEGIN_MARKER!r} in {psr.filename}"
|
|
)
|
|
start = psr.getpos()
|
|
|
|
# Find end marker, then delete everything after it
|
|
while tkn := psr.next(raw=True):
|
|
if tkn.text == END_MARKER:
|
|
break
|
|
del psr.tokens[psr.getpos() - 1 :]
|
|
|
|
# Parse from start
|
|
psr.setpos(start)
|
|
self.instrs = {}
|
|
self.supers = {}
|
|
self.macros = {}
|
|
self.families = {}
|
|
while thing := psr.definition():
|
|
match thing:
|
|
case parser.InstDef(name=name):
|
|
self.instrs[name] = Instruction(thing)
|
|
case parser.Super(name):
|
|
self.supers[name] = thing
|
|
case parser.Macro(name):
|
|
self.macros[name] = thing
|
|
case parser.Family(name):
|
|
self.families[name] = thing
|
|
case _:
|
|
typing.assert_never(thing)
|
|
if not psr.eof():
|
|
raise psr.make_syntax_error("Extra stuff at the end")
|
|
|
|
print(
|
|
f"Read {len(self.instrs)} instructions/ops, "
|
|
f"{len(self.supers)} supers, {len(self.macros)} macros, "
|
|
f"and {len(self.families)} families from {self.filename}",
|
|
file=sys.stderr,
|
|
)
|
|
|
|
def analyze(self) -> None:
|
|
"""Analyze the inputs.
|
|
|
|
Raises SystemExit if there is an error.
|
|
"""
|
|
self.find_predictions()
|
|
self.map_families()
|
|
self.check_families()
|
|
self.analyze_supers_and_macros()
|
|
|
|
def find_predictions(self) -> None:
|
|
"""Find the instructions that need PREDICTED() labels."""
|
|
for instr in self.instrs.values():
|
|
for target in re.findall(RE_PREDICTED, instr.block.text):
|
|
if target_instr := self.instrs.get(target):
|
|
target_instr.predicted = True
|
|
else:
|
|
self.error(
|
|
f"Unknown instruction {target!r} predicted in {instr.name!r}",
|
|
instr.inst, # TODO: Use better location
|
|
)
|
|
|
|
def map_families(self) -> None:
|
|
"""Make instruction names back to their family, if they have one."""
|
|
for family in self.families.values():
|
|
for member in family.members:
|
|
if member_instr := self.instrs.get(member):
|
|
member_instr.family = family
|
|
else:
|
|
self.error(
|
|
f"Unknown instruction {member!r} referenced in family {family.name!r}",
|
|
family,
|
|
)
|
|
|
|
def check_families(self) -> None:
|
|
"""Check each family:
|
|
|
|
- Must have at least 2 members
|
|
- All members must be known instructions
|
|
- All members must have the same cache, input and output effects
|
|
"""
|
|
for family in self.families.values():
|
|
if len(family.members) < 2:
|
|
self.error(f"Family {family.name!r} has insufficient members", family)
|
|
members = [member for member in family.members if member in self.instrs]
|
|
if members != family.members:
|
|
unknown = set(family.members) - set(members)
|
|
self.error(
|
|
f"Family {family.name!r} has unknown members: {unknown}", family
|
|
)
|
|
if len(members) < 2:
|
|
continue
|
|
head = self.instrs[members[0]]
|
|
cache = head.cache_offset
|
|
input = len(head.input_effects)
|
|
output = len(head.output_effects)
|
|
for member in members[1:]:
|
|
instr = self.instrs[member]
|
|
c = instr.cache_offset
|
|
i = len(instr.input_effects)
|
|
o = len(instr.output_effects)
|
|
if (c, i, o) != (cache, input, output):
|
|
self.error(
|
|
f"Family {family.name!r} has inconsistent "
|
|
f"(cache, inputs, outputs) effects:\n"
|
|
f" {family.members[0]} = {(cache, input, output)}; "
|
|
f"{member} = {(c, i, o)}",
|
|
family,
|
|
)
|
|
|
|
def analyze_supers_and_macros(self) -> None:
|
|
"""Analyze each super- and macro instruction."""
|
|
self.super_instrs = {}
|
|
self.macro_instrs = {}
|
|
for name, super in self.supers.items():
|
|
self.super_instrs[name] = self.analyze_super(super)
|
|
for name, macro in self.macros.items():
|
|
self.macro_instrs[name] = self.analyze_macro(macro)
|
|
|
|
def analyze_super(self, super: parser.Super) -> SuperInstruction:
|
|
components = self.check_super_components(super)
|
|
stack, initial_sp = self.stack_analysis(components)
|
|
sp = initial_sp
|
|
parts: list[Component] = []
|
|
for component in components:
|
|
match component:
|
|
case parser.CacheEffect() as ceffect:
|
|
parts.append(ceffect)
|
|
case Instruction() as instr:
|
|
input_mapping = {}
|
|
for ieffect in reversed(instr.input_effects):
|
|
sp -= 1
|
|
if ieffect.name != UNUSED:
|
|
input_mapping[stack[sp]] = ieffect
|
|
output_mapping = {}
|
|
for oeffect in instr.output_effects:
|
|
if oeffect.name != UNUSED:
|
|
output_mapping[stack[sp]] = oeffect
|
|
sp += 1
|
|
parts.append(Component(instr, input_mapping, output_mapping))
|
|
case _:
|
|
typing.assert_never(component)
|
|
final_sp = sp
|
|
return SuperInstruction(super.name, stack, initial_sp, final_sp, super, parts)
|
|
|
|
def analyze_macro(self, macro: parser.Macro) -> MacroInstruction:
|
|
components = self.check_macro_components(macro)
|
|
stack, initial_sp = self.stack_analysis(components)
|
|
sp = initial_sp
|
|
parts: list[Component | parser.CacheEffect] = []
|
|
for component in components:
|
|
match component:
|
|
case parser.CacheEffect() as ceffect:
|
|
parts.append(ceffect)
|
|
case Instruction() as instr:
|
|
input_mapping = {}
|
|
for ieffect in reversed(instr.input_effects):
|
|
sp -= 1
|
|
if ieffect.name != UNUSED:
|
|
input_mapping[stack[sp]] = ieffect
|
|
output_mapping = {}
|
|
for oeffect in instr.output_effects:
|
|
if oeffect.name != UNUSED:
|
|
output_mapping[stack[sp]] = oeffect
|
|
sp += 1
|
|
parts.append(Component(instr, input_mapping, output_mapping))
|
|
case _:
|
|
typing.assert_never(component)
|
|
final_sp = sp
|
|
return MacroInstruction(macro.name, stack, initial_sp, final_sp, macro, parts)
|
|
|
|
def check_super_components(self, super: parser.Super) -> list[Instruction]:
|
|
components: list[Instruction] = []
|
|
for op in super.ops:
|
|
if op.name not in self.instrs:
|
|
self.error(f"Unknown instruction {op.name!r}", super)
|
|
else:
|
|
components.append(self.instrs[op.name])
|
|
return components
|
|
|
|
def check_macro_components(
|
|
self, macro: parser.Macro
|
|
) -> list[InstructionOrCacheEffect]:
|
|
components: list[InstructionOrCacheEffect] = []
|
|
for uop in macro.uops:
|
|
match uop:
|
|
case parser.OpName(name):
|
|
if name not in self.instrs:
|
|
self.error(f"Unknown instruction {name!r}", macro)
|
|
components.append(self.instrs[name])
|
|
case parser.CacheEffect():
|
|
components.append(uop)
|
|
case _:
|
|
typing.assert_never(uop)
|
|
return components
|
|
|
|
def stack_analysis(
|
|
self, components: typing.Iterable[InstructionOrCacheEffect]
|
|
) -> tuple[list[str], int]:
|
|
"""Analyze a super-instruction or macro.
|
|
|
|
Print an error if there's a cache effect (which we don't support yet).
|
|
|
|
Return the list of variable names and the initial stack pointer.
|
|
"""
|
|
lowest = current = highest = 0
|
|
for thing in components:
|
|
match thing:
|
|
case Instruction() as instr:
|
|
current -= len(instr.input_effects)
|
|
lowest = min(lowest, current)
|
|
current += len(instr.output_effects)
|
|
highest = max(highest, current)
|
|
case parser.CacheEffect():
|
|
pass
|
|
case _:
|
|
typing.assert_never(thing)
|
|
# At this point, 'current' is the net stack effect,
|
|
# and 'lowest' and 'highest' are the extremes.
|
|
# Note that 'lowest' may be negative.
|
|
stack = [f"_tmp_{i+1}" for i in range(highest - lowest)]
|
|
return stack, -lowest
|
|
|
|
def write_instructions(self) -> None:
|
|
"""Write instructions to output file."""
|
|
with open(self.output_filename, "w") as f:
|
|
# Write provenance header
|
|
f.write(f"// This file is generated by {os.path.relpath(__file__)}\n")
|
|
f.write(f"// from {os.path.relpath(self.filename)}\n")
|
|
f.write(f"// Do not edit!\n")
|
|
|
|
# Create formatter; the rest of the code uses this.
|
|
self.out = Formatter(f, 8)
|
|
|
|
# Write and count regular instructions
|
|
n_instrs = 0
|
|
for name, instr in self.instrs.items():
|
|
if instr.kind != "inst":
|
|
continue # ops are not real instructions
|
|
n_instrs += 1
|
|
self.out.emit("")
|
|
with self.out.block(f"TARGET({name})"):
|
|
if instr.predicted:
|
|
self.out.emit(f"PREDICTED({name});")
|
|
instr.write(self.out)
|
|
if not always_exits(instr.block):
|
|
self.out.emit(f"DISPATCH();")
|
|
|
|
# Write and count super-instructions
|
|
n_supers = 0
|
|
for sup in self.super_instrs.values():
|
|
n_supers += 1
|
|
self.write_super(sup)
|
|
|
|
# Write and count macro instructions
|
|
n_macros = 0
|
|
for macro in self.macro_instrs.values():
|
|
n_macros += 1
|
|
self.write_macro(macro)
|
|
|
|
print(
|
|
f"Wrote {n_instrs} instructions, {n_supers} supers, "
|
|
f"and {n_macros} macros to {self.output_filename}",
|
|
file=sys.stderr,
|
|
)
|
|
|
|
def write_super(self, sup: SuperInstruction) -> None:
|
|
"""Write code for a super-instruction."""
|
|
with self.wrap_super_or_macro(sup):
|
|
first = True
|
|
for comp in sup.parts:
|
|
if not first:
|
|
self.out.emit("NEXTOPARG();")
|
|
self.out.emit("next_instr++;")
|
|
first = False
|
|
comp.write_body(self.out, 0)
|
|
if comp.instr.cache_offset:
|
|
self.out.emit(f"next_instr += {comp.instr.cache_offset};")
|
|
|
|
def write_macro(self, mac: MacroInstruction) -> None:
|
|
"""Write code for a macro instruction."""
|
|
with self.wrap_super_or_macro(mac):
|
|
cache_adjust = 0
|
|
for part in mac.parts:
|
|
match part:
|
|
case parser.CacheEffect(size=size):
|
|
cache_adjust += size
|
|
case Component() as comp:
|
|
comp.write_body(self.out, cache_adjust)
|
|
cache_adjust += comp.instr.cache_offset
|
|
|
|
if cache_adjust:
|
|
self.out.emit(f"next_instr += {cache_adjust};")
|
|
|
|
@contextlib.contextmanager
|
|
def wrap_super_or_macro(self, up: SuperOrMacroInstruction):
|
|
"""Shared boilerplate for super- and macro instructions."""
|
|
self.out.emit("")
|
|
with self.out.block(f"TARGET({up.name})"):
|
|
for i, var in enumerate(up.stack):
|
|
if i < up.initial_sp:
|
|
self.out.emit(f"PyObject *{var} = PEEK({up.initial_sp - i});")
|
|
else:
|
|
self.out.emit(f"PyObject *{var};")
|
|
|
|
yield
|
|
|
|
if up.final_sp > up.initial_sp:
|
|
self.out.emit(f"STACK_GROW({up.final_sp - up.initial_sp});")
|
|
elif up.final_sp < up.initial_sp:
|
|
self.out.emit(f"STACK_SHRINK({up.initial_sp - up.final_sp});")
|
|
for i, var in enumerate(reversed(up.stack[: up.final_sp]), 1):
|
|
self.out.emit(f"POKE({i}, {var});")
|
|
|
|
self.out.emit(f"DISPATCH();")
|
|
|
|
|
|
def always_exits(block: parser.Block) -> bool:
|
|
"""Determine whether a block always ends in a return/goto/etc."""
|
|
text = block.text
|
|
lines = text.splitlines()
|
|
while lines and not lines[-1].strip():
|
|
lines.pop()
|
|
if not lines or lines[-1].strip() != "}":
|
|
return False
|
|
lines.pop()
|
|
if not lines:
|
|
return False
|
|
line = lines.pop().rstrip()
|
|
# Indent must match exactly (TODO: Do something better)
|
|
if line[:12] != " " * 12:
|
|
return False
|
|
line = line[12:]
|
|
return line.startswith(
|
|
("goto ", "return ", "DISPATCH", "GO_TO_", "Py_UNREACHABLE()")
|
|
)
|
|
|
|
|
|
def main():
|
|
"""Parse command line, parse input, analyze, write output."""
|
|
args = arg_parser.parse_args() # Prints message and sys.exit(2) on error
|
|
a = Analyzer(args.input, args.output) # Raises OSError if input unreadable
|
|
a.parse() # Raises SyntaxError on failure
|
|
a.analyze() # Prints messages and sets a.errors on failure
|
|
if a.errors:
|
|
sys.exit(f"Found {a.errors} errors")
|
|
a.write_instructions() # Raises OSError if output can't be written
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|