cpython/Tools/cases_generator/generate_cases.py

1012 lines
38 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
from parser import StackEffect
HERE = os.path.dirname(__file__)
ROOT = os.path.join(HERE, "../..")
THIS = os.path.relpath(__file__, ROOT)
DEFAULT_INPUT = os.path.relpath(os.path.join(ROOT, "Python/bytecodes.c"))
DEFAULT_OUTPUT = os.path.relpath(os.path.join(ROOT, "Python/generated_cases.c.h"))
DEFAULT_METADATA_OUTPUT = os.path.relpath(
os.path.join(ROOT, "Python/opcode_metadata.h")
)
BEGIN_MARKER = "// BEGIN BYTECODES //"
END_MARKER = "// END BYTECODES //"
RE_PREDICTED = r"^\s*(?:PREDICT\(|GO_TO_INSTRUCTION\(|DEOPT_IF\(.*?,\s*)(\w+)\);\s*$"
UNUSED = "unused"
BITS_PER_CODE_UNIT = 16
arg_parser = argparse.ArgumentParser(
description="Generate the code for the interpreter switch.",
formatter_class=argparse.ArgumentDefaultsHelpFormatter,
)
arg_parser.add_argument(
"-i", "--input", type=str, help="Instruction definitions", default=DEFAULT_INPUT
)
arg_parser.add_argument(
"-o", "--output", type=str, help="Generated code", default=DEFAULT_OUTPUT
)
arg_parser.add_argument(
"-m",
"--metadata",
action="store_true",
help=f"Generate metadata instead, changes output default to {DEFAULT_METADATA_OUTPUT}",
)
def effect_size(effect: StackEffect) -> tuple[int, str]:
"""Return the 'size' impact of a stack effect.
Returns a tuple (numeric, symbolic) where:
- numeric is an int giving the statically analyzable size of the effect
- symbolic is a string representing a variable effect (e.g. 'oparg*2')
At most one of these will be non-zero / non-empty.
"""
if effect.size:
return 0, effect.size
else:
return 1, ""
def maybe_parenthesize(sym: str) -> str:
"""Add parentheses around a string if it contains an operator.
An exception is made for '*' which is common and harmless
in the context where the symbolic size is used.
"""
if re.match(r"^[\s\w*]+$", sym):
return sym
else:
return f"({sym})"
def list_effect_size(effects: list[StackEffect]) -> tuple[int, str]:
numeric = 0
symbolic: list[str] = []
for effect in effects:
diff, sym = effect_size(effect)
numeric += diff
if sym:
symbolic.append(maybe_parenthesize(sym))
return numeric, " + ".join(symbolic)
def string_effect_size(arg: tuple[int, str]) -> str:
numeric, symbolic = arg
if numeric and symbolic:
return f"{numeric} + {symbolic}"
elif symbolic:
return symbolic
else:
return str(numeric)
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("}")
def stack_adjust(self, diff: int, input_effects: list[StackEffect], output_effects: list[StackEffect]):
# TODO: Get rid of 'diff' parameter
shrink, isym = list_effect_size(input_effects)
grow, osym = list_effect_size(output_effects)
diff += grow - shrink
if isym and isym != osym:
self.emit(f"STACK_SHRINK({isym});")
if diff < 0:
self.emit(f"STACK_SHRINK({-diff});")
if diff > 0:
self.emit(f"STACK_GROW({diff});")
if osym and osym != isym:
self.emit(f"STACK_GROW({osym});")
def declare(self, dst: StackEffect, src: StackEffect | None):
if dst.name == UNUSED:
return
typ = f"{dst.type}" if dst.type else "PyObject *"
init = ""
if src:
cast = self.cast(dst, src)
init = f" = {cast}{src.name}"
sepa = "" if typ.endswith("*") else " "
self.emit(f"{typ}{sepa}{dst.name}{init};")
def assign(self, dst: StackEffect, src: StackEffect):
if src.name == UNUSED:
return
cast = self.cast(dst, src)
if m := re.match(r"^PEEK\((.*)\)$", dst.name):
self.emit(f"POKE({m.group(1)}, {cast}{src.name});")
elif m := re.match(r"^&PEEK\(.*\)$", dst.name):
# NOTE: MOVE_ITEMS() does not actually exist.
# The only supported output array forms are:
# - unused[...]
# - X[...] where X[...] matches an input array exactly
self.emit(f"MOVE_ITEMS({dst.name}, {src.name}, {src.size});")
elif m := re.match(r"^REG\(oparg(\d+)\)$", dst.name):
self.emit(f"Py_XSETREF({dst.name}, {cast}{src.name});")
else:
self.emit(f"{dst.name} = {cast}{src.name};")
def cast(self, dst: StackEffect, src: StackEffect) -> str:
return f"({dst.type or 'PyObject *'})" if src.type != dst.type else ""
@dataclasses.dataclass
class Instruction:
"""An instruction with additional data and code."""
# Parts of the underlying instruction definition
inst: parser.InstDef
register: bool
kind: typing.Literal["inst", "op", "legacy"] # Legacy means no (input -- output)
name: str
block: parser.Block
block_text: list[str] # Block.text, less curlies, less PREDICT() calls
predictions: list[str] # Prediction targets (instruction names)
# Computed by constructor
always_exits: bool
cache_offset: int
cache_effects: list[parser.CacheEffect]
input_effects: list[StackEffect]
output_effects: list[StackEffect]
unmoved_names: frozenset[str]
instr_fmt: str
# Parallel to input_effects; set later
input_registers: list[str] = dataclasses.field(repr=False)
output_registers: list[str] = dataclasses.field(repr=False)
# Set later
family: parser.Family | None = None
predicted: bool = False
def __init__(self, inst: parser.InstDef):
self.inst = inst
self.register = inst.register
self.kind = inst.kind
self.name = inst.name
self.block = inst.block
self.block_text, self.predictions = extract_block_text(self.block)
self.always_exits = always_exits(self.block_text)
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, StackEffect)
]
self.output_effects = inst.outputs # For consistency/completeness
unmoved_names: set[str] = set()
for ieffect, oeffect in zip(self.input_effects, self.output_effects):
if ieffect.name == oeffect.name:
unmoved_names.add(ieffect.name)
else:
break
self.unmoved_names = frozenset(unmoved_names)
if self.register:
num_regs = len(self.input_effects) + len(self.output_effects)
num_dummies = (num_regs // 2) * 2 + 1 - num_regs
fmt = "I" + "B"*num_regs + "X"*num_dummies
else:
if variable_used(inst, "oparg"):
fmt = "IB"
else:
fmt = "IX"
cache = "C"
for ce in self.cache_effects:
for _ in range(ce.size):
fmt += cache
cache = "0"
self.instr_fmt = fmt
def analyze_registers(self, a: "Analyzer") -> None:
regs = iter(("REG(oparg1)", "REG(oparg2)", "REG(oparg3)"))
try:
self.input_registers = [
next(regs) for ieff in self.input_effects if ieff.name != UNUSED
]
self.output_registers = [
next(regs) for oeff in self.output_effects if oeff.name != UNUSED
]
except StopIteration: # Running out of registers
a.error(
f"Instruction {self.name} has too many register effects", node=self.inst
)
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");'
)
if not self.register:
# Write input stack effect variable declarations and initializations
ieffects = list(reversed(self.input_effects))
for i, ieffect in enumerate(ieffects):
isize = string_effect_size(list_effect_size(ieffects[:i+1]))
if ieffect.size:
src = StackEffect(f"&PEEK({isize})", "PyObject **")
else:
src = StackEffect(f"PEEK({isize})", "")
out.declare(ieffect, src)
else:
# Write input register variable declarations and initializations
for ieffect, reg in zip(self.input_effects, self.input_registers):
src = StackEffect(reg, "")
out.declare(ieffect, src)
# Write output stack effect variable declarations
input_names = {ieffect.name for ieffect in self.input_effects}
for oeffect in self.output_effects:
if oeffect.name not in input_names:
out.declare(oeffect, None)
# out.emit(f"JUMPBY(OPSIZE({self.inst.name}) - 1);")
self.write_body(out, 0)
# Skip the rest if the block always exits
if self.always_exits:
return
if not self.register:
# Write net stack growth/shrinkage
out.stack_adjust(0, self.input_effects, self.output_effects)
# Write output stack effect assignments
oeffects = list(reversed(self.output_effects))
for i, oeffect in enumerate(oeffects):
if oeffect.name in self.unmoved_names:
continue
osize = string_effect_size(list_effect_size(oeffects[:i+1]))
if oeffect.size:
dst = StackEffect(f"&PEEK({osize})", "PyObject **")
else:
dst = StackEffect(f"PEEK({osize})", "")
out.assign(dst, oeffect)
else:
# Write output register assignments
for oeffect, reg in zip(self.output_effects, self.output_registers):
dst = StackEffect(reg, "")
out.assign(dst, oeffect)
# Write cache effect
if self.cache_offset:
out.emit(f"JUMPBY({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.
typ = "PyObject *"
func = "read_obj"
else:
typ = f"uint{bits}_t "
func = f"read_u{bits}"
out.emit(
f"{typ}{ceffect.name} = {func}(&next_instr[{cache_offset}].cache);"
)
cache_offset += ceffect.size
assert cache_offset == self.cache_offset + cache_adjust
# Write the body, substituting a goto for ERROR_IF() and other stuff
assert dedent <= 0
extra = " " * -dedent
for line in self.block_text:
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.
if not self.register:
# Don't pop common input/output effects at the bottom!
# These aren't DECREF'ed so they can stay.
ieffs = list(self.input_effects)
oeffs = list(self.output_effects)
while ieffs and oeffs and ieffs[0] == oeffs[0]:
ieffs.pop(0)
oeffs.pop(0)
ninputs, symbolic = list_effect_size(ieffs)
if ninputs:
label = f"pop_{ninputs}_{label}"
else:
symbolic = ""
if symbolic:
out.write_raw(
f"{extra}{space}if ({cond}) {{ STACK_SHRINK({symbolic}); goto {label}; }}\n"
)
else:
out.write_raw(f"{extra}{space}if ({cond}) goto {label};\n")
elif m := re.match(r"(\s*)DECREF_INPUTS\(\);\s*$", line):
if not self.register:
space = m.group(1)
for ieff in self.input_effects:
if ieff.name not in self.unmoved_names:
out.write_raw(f"{extra}{space}Py_DECREF({ieff.name});\n")
else:
out.write_raw(extra + line)
InstructionOrCacheEffect = Instruction | parser.CacheEffect
StackEffectMapping = list[tuple[StackEffect, StackEffect]]
@dataclasses.dataclass
class Component:
instr: Instruction
input_mapping: StackEffectMapping
output_mapping: StackEffectMapping
def write_body(self, out: Formatter, cache_adjust: int) -> None:
with out.block(""):
for var, ieffect in self.input_mapping:
out.declare(ieffect, var)
for _, oeffect in self.output_mapping:
out.declare(oeffect, None)
self.instr.write_body(out, dedent=-4, cache_adjust=cache_adjust)
for var, oeffect in self.output_mapping:
out.assign(var, oeffect)
@dataclasses.dataclass
class SuperOrMacroInstruction:
"""Common fields for super- and macro instructions."""
name: str
stack: list[StackEffect]
initial_sp: int
final_sp: int
instr_fmt: str
@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]
INSTR_FMT_PREFIX = "INSTR_FMT_"
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
everything: list[parser.InstDef | parser.Super | parser.Macro]
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.everything = []
self.instrs = {}
self.supers = {}
self.macros = {}
self.families = {}
while thing := psr.definition():
match thing:
case parser.InstDef(name=name):
self.instrs[name] = Instruction(thing)
self.everything.append(thing)
case parser.Super(name):
self.supers[name] = thing
self.everything.append(thing)
case parser.Macro(name):
self.macros[name] = thing
self.everything.append(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_register_instrs()
self.analyze_supers_and_macros()
def find_predictions(self) -> None:
"""Find the instructions that need PREDICTED() labels."""
for instr in self.instrs.values():
targets = set(instr.predictions)
for line in instr.block_text:
if m := re.match(RE_PREDICTED, line):
targets.add(m.group(1))
for target in targets:
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_register_instrs(self) -> None:
for instr in self.instrs.values():
if instr.register:
instr.analyze_registers(self)
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] = []
format = ""
for instr in components:
part, sp = self.analyze_instruction(instr, stack, sp)
parts.append(part)
format += instr.instr_fmt
final_sp = sp
return SuperInstruction(super.name, stack, initial_sp, final_sp, format, 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] = []
format = "IB" # Macros don't support register instructions yet
cache = "C"
for component in components:
match component:
case parser.CacheEffect() as ceffect:
parts.append(ceffect)
for _ in range(ceffect.size):
format += cache
cache = "0"
case Instruction() as instr:
part, sp = self.analyze_instruction(instr, stack, sp)
parts.append(part)
for ce in instr.cache_effects:
for _ in range(ce.size):
format += cache
cache = "0"
case _:
typing.assert_never(component)
final_sp = sp
return MacroInstruction(macro.name, stack, initial_sp, final_sp, format, macro, parts)
def analyze_instruction(
self, instr: Instruction, stack: list[StackEffect], sp: int
) -> tuple[Component, int]:
input_mapping: StackEffectMapping = []
for ieffect in reversed(instr.input_effects):
sp -= 1
input_mapping.append((stack[sp], ieffect))
output_mapping: StackEffectMapping = []
for oeffect in instr.output_effects:
output_mapping.append((stack[sp], oeffect))
sp += 1
return Component(instr, input_mapping, output_mapping), sp
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[StackEffect], int]:
"""Analyze a super-instruction or macro.
Ignore cache effects.
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:
if any(eff.size for eff in instr.input_effects + instr.output_effects):
# TODO: Eventually this will be needed, at least for macros.
self.error(
f"Instruction {instr.name!r} has variable-sized stack effect, "
"which are not supported in super- or macro instructions",
instr.inst, # TODO: Pass name+location of super/macro
)
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.
# TODO: Reverse the numbering.
stack = [
StackEffect(f"_tmp_{i+1}", "") for i in reversed(range(highest - lowest))
]
return stack, -lowest
def write_metadata(self) -> None:
"""Write instruction metadata to output file."""
# Compute the set of all instruction formats.
all_formats: set[str] = set()
for thing in self.everything:
match thing:
case parser.InstDef():
format = self.instrs[thing.name].instr_fmt
case parser.Super():
format = self.super_instrs[thing.name].instr_fmt
case parser.Macro():
format = self.macro_instrs[thing.name].instr_fmt
case _:
typing.assert_never(thing)
all_formats.add(format)
# Turn it into a list of enum definitions.
format_enums = [INSTR_FMT_PREFIX + format for format in sorted(all_formats)]
with open(self.output_filename, "w") as f:
# Write provenance header
f.write(f"// This file is generated by {THIS} --metadata\n")
f.write(f"// from {os.path.relpath(self.filename, ROOT)}\n")
f.write(f"// Do not edit!\n")
# Create formatter; the rest of the code uses this
self.out = Formatter(f, 0)
# Write variable definition
self.out.emit("enum Direction { DIR_NONE, DIR_READ, DIR_WRITE };")
self.out.emit(f"enum InstructionFormat {{ {', '.join(format_enums)} }};")
self.out.emit("static const struct {")
with self.out.indent():
self.out.emit("short n_popped;")
self.out.emit("short n_pushed;")
self.out.emit("enum Direction dir_op1;")
self.out.emit("enum Direction dir_op2;")
self.out.emit("enum Direction dir_op3;")
self.out.emit("bool valid_entry;")
self.out.emit("enum InstructionFormat instr_format;")
self.out.emit("} _PyOpcode_opcode_metadata[256] = {")
# Write metadata for each instruction
for thing in self.everything:
match thing:
case parser.InstDef():
if thing.kind != "op":
self.write_metadata_for_inst(self.instrs[thing.name])
case parser.Super():
self.write_metadata_for_super(self.super_instrs[thing.name])
case parser.Macro():
self.write_metadata_for_macro(self.macro_instrs[thing.name])
case _:
typing.assert_never(thing)
# Write end of array
self.out.emit("};")
def write_metadata_for_inst(self, instr: Instruction) -> None:
"""Write metadata for a single instruction."""
dir_op1 = dir_op2 = dir_op3 = "DIR_NONE"
if instr.kind == "legacy":
n_popped = n_pushed = -1
assert not instr.register
else:
n_popped, sym_popped = list_effect_size(instr.input_effects)
n_pushed, sym_pushed = list_effect_size(instr.output_effects)
if sym_popped or sym_pushed:
# TODO: Record symbolic effects (how?)
n_popped = n_pushed = -1
if instr.register:
directions: list[str] = []
directions.extend("DIR_READ" for _ in instr.input_effects)
directions.extend("DIR_WRITE" for _ in instr.output_effects)
directions.extend("DIR_NONE" for _ in range(3))
dir_op1, dir_op2, dir_op3 = directions[:3]
n_popped = n_pushed = 0
self.out.emit(
f' [{instr.name}] = {{ {n_popped}, {n_pushed}, {dir_op1}, {dir_op2}, {dir_op3}, true, {INSTR_FMT_PREFIX}{instr.instr_fmt} }},'
)
def write_metadata_for_super(self, sup: SuperInstruction) -> None:
"""Write metadata for a super-instruction."""
n_popped = sum(len(comp.instr.input_effects) for comp in sup.parts)
n_pushed = sum(len(comp.instr.output_effects) for comp in sup.parts)
dir_op1 = dir_op2 = dir_op3 = "DIR_NONE"
self.out.emit(
f' [{sup.name}] = {{ {n_popped}, {n_pushed}, {dir_op1}, {dir_op2}, {dir_op3}, true, {INSTR_FMT_PREFIX}{sup.instr_fmt} }},'
)
def write_metadata_for_macro(self, mac: MacroInstruction) -> None:
"""Write metadata for a macro-instruction."""
parts = [comp for comp in mac.parts if isinstance(comp, Component)]
n_popped = sum(len(comp.instr.input_effects) for comp in parts)
n_pushed = sum(len(comp.instr.output_effects) for comp in parts)
dir_op1 = dir_op2 = dir_op3 = "DIR_NONE"
self.out.emit(
f' [{mac.name}] = {{ {n_popped}, {n_pushed}, {dir_op1}, {dir_op2}, {dir_op3}, true, {INSTR_FMT_PREFIX}{mac.instr_fmt} }},'
)
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 {THIS}\n")
f.write(f"// from {os.path.relpath(self.filename, ROOT)}\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 instructions of all kinds
n_instrs = 0
n_supers = 0
n_macros = 0
for thing in self.everything:
match thing:
case parser.InstDef():
if thing.kind != "op":
n_instrs += 1
self.write_instr(self.instrs[thing.name])
case parser.Super():
n_supers += 1
self.write_super(self.super_instrs[thing.name])
case parser.Macro():
n_macros += 1
self.write_macro(self.macro_instrs[thing.name])
case _:
typing.assert_never(thing)
print(
f"Wrote {n_instrs} instructions, {n_supers} supers, "
f"and {n_macros} macros to {self.output_filename}",
file=sys.stderr,
)
def write_instr(self, instr: Instruction) -> None:
name = instr.name
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 instr.always_exits:
for prediction in instr.predictions:
self.out.emit(f"PREDICT({prediction});")
self.out.emit(f"DISPATCH();")
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 first:
pass
# self.out.emit("JUMPBY(OPSIZE(opcode) - 1);")
else:
self.out.emit("NEXTOPARG();")
self.out.emit("JUMPBY(1);")
# self.out.emit("JUMPBY(OPSIZE(opcode));")
first = False
comp.write_body(self.out, 0)
if comp.instr.cache_offset:
self.out.emit(f"JUMPBY({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"JUMPBY({cache_adjust});")
@contextlib.contextmanager
def wrap_super_or_macro(self, up: SuperOrMacroInstruction):
"""Shared boilerplate for super- and macro instructions."""
# TODO: Somewhere (where?) make it so that if one instruction
# has an output that is input to another, and the variable names
# and types match and don't conflict with other instructions,
# that variable is declared with the right name and type in the
# outer block, rather than trusting the compiler to optimize it.
self.out.emit("")
with self.out.block(f"TARGET({up.name})"):
for i, var in reversed(list(enumerate(up.stack))):
src = None
if i < up.initial_sp:
src = StackEffect(f"PEEK({up.initial_sp - i})", "")
self.out.declare(var, src)
yield
# TODO: Use slices of up.stack instead of numeric values
self.out.stack_adjust(up.final_sp - up.initial_sp, [], [])
for i, var in enumerate(reversed(up.stack[: up.final_sp]), 1):
dst = StackEffect(f"PEEK({i})", "")
self.out.assign(dst, var)
self.out.emit(f"DISPATCH();")
def extract_block_text(block: parser.Block) -> tuple[list[str], list[str]]:
# Get lines of text with proper dedent
blocklines = block.text.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()
# Separate PREDICT(...) macros from end
predictions: list[str] = []
while blocklines and (m := re.match(r"^\s*PREDICT\((\w+)\);\s*$", blocklines[-1])):
predictions.insert(0, m.group(1))
blocklines.pop()
return blocklines, predictions
def always_exits(lines: list[str]) -> bool:
"""Determine whether a block always ends in a return/goto/etc."""
if not lines:
return False
line = lines[-1].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 variable_used(node: parser.Node, name: str) -> bool:
"""Determine whether a variable with a given name is used in a node."""
return any(token.kind == "IDENTIFIER" and token.text == name for token in node.tokens)
def main():
"""Parse command line, parse input, analyze, write output."""
args = arg_parser.parse_args() # Prints message and sys.exit(2) on error
if args.metadata:
if args.output == DEFAULT_OUTPUT:
args.output = DEFAULT_METADATA_OUTPUT
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")
if args.metadata:
a.write_metadata()
else:
a.write_instructions() # Raises OSError if output can't be written
if __name__ == "__main__":
main()