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mirror of https://github.com/catseye/SixtyPical.git synced 2024-11-26 14:49:15 +00:00

More sophisticated static analysis: writeable, touched, meaningful.

This commit is contained in:
Chris Pressey 2015-10-18 22:27:51 +01:00
parent 8b30a232fa
commit fd07f4bae9

View File

@ -8,10 +8,6 @@ from sixtypical.model import (
)
UNINITIALIZED = 'UNINITIALIZED'
INITIALIZED = 'INITIALIZED'
class StaticAnalysisError(ValueError):
pass
@ -41,76 +37,89 @@ class TypeMismatchError(StaticAnalysisError):
class Context():
"""
A location is touched if it was changed (or even potentially
changed) during this routine, or some routine called by this routine.
A location is meaningful if it was an input to this routine,
or if it was set to a meaningful value by some operation in this
routine (or some routine called by this routine.
A location is writeable if it was listed in the outputs and trashes
lists of this routine.
"""
def __init__(self, inputs, outputs, trashes):
self._store = {} # Ref -> INITALIZED/UNINITIALIZED
self._writeables = set()
self._touched = set()
self._meaningful = set()
self._writeable = set()
for ref in inputs:
self._store.setdefault(ref, INITIALIZED)
self._meaningful.add(ref)
output_names = set()
for ref in outputs:
output_names.add(ref.name)
self._store.setdefault(ref, UNINITIALIZED)
self._writeables.add(ref.name)
self._writeable.add(ref)
for ref in trashes:
if ref.name in output_names:
raise UsageClashError(ref.name)
self._store.setdefault(ref, UNINITIALIZED)
self._writeables.add(ref.name)
self._writeable.add(ref)
def clone(self):
c = Context([], [], [])
c._store = dict(self._store)
c._writeables = set(self._writeables)
c._touched = set(self._touched)
c._meaningful = set(self._meaningful)
c._writeable = set(self._writeable)
return c
def set_from(self, c):
self._store = dict(c._store)
self._writeables = set(c._writeables)
self._touched = set(c._touched)
self._meaningful = set(c._meaningful)
self._writeable = set(c._writeable)
def each_initialized(self):
for key, value in self._store.iteritems():
if value == INITIALIZED:
yield key
def each_meaningful(self):
for ref in self._meaningful:
yield ref
def assert_initialized(self, *refs, **kwargs):
def each_touched(self):
for ref in self._touched:
yield ref
def assert_meaningful(self, *refs, **kwargs):
exception_class = kwargs.get('exception_class', UninitializedAccessError)
for ref in refs:
if isinstance(ref, ConstantRef):
pass
elif isinstance(ref, LocationRef):
if self.get(ref) != INITIALIZED:
if ref not in self._meaningful:
raise exception_class(ref.name)
else:
raise ValueError(ref)
def assert_writeable(self, *refs):
for ref in refs:
if ref.name not in self._writeables:
if ref not in self._writeable:
raise IllegalWriteError(ref.name)
def set_initialized(self, *refs):
def set_touched(self, *refs):
for ref in refs:
self.set(ref, INITIALIZED)
self._touched.add(ref)
def set_uninitialized(self, *refs):
def set_meaningful(self, *refs):
for ref in refs:
self.set(ref, UNINITIALIZED)
self._meaningful.add(ref)
def get(self, ref):
if isinstance(ref, ConstantRef):
return INITIALIZED
elif isinstance(ref, LocationRef):
if ref not in self._store:
return UNINITIALIZED
return self._store[ref]
else:
raise ValueError(ref)
def set(self, ref, value):
assert isinstance(ref, LocationRef)
self._store[ref] = value
def set_unmeaningful(self, *refs):
for ref in refs:
if ref in self._meaningful:
self._meaningful.remove(ref)
def set_written(self, *refs):
"""A "helper" method which does the following common sequence for
the given refs: asserts they're all writable, and sets them all
as touched and meaningful."""
self.assert_writeable(*refs)
self.set_touched(*refs)
self.set_meaningful(*refs)
def analyze_program(program):
assert isinstance(program, Program)
@ -127,7 +136,10 @@ def analyze_routine(routine, routines):
context = Context(routine.inputs, routine.outputs, routine.trashes)
analyze_block(routine.block, context, routines)
for ref in routine.outputs:
context.assert_initialized(ref, exception_class=UninitializedOutputError)
context.assert_meaningful(ref, exception_class=UninitializedOutputError)
for ref in context.each_touched():
if ref not in routine.outputs and ref not in routine.trashes:
raise IllegalWriteError(ref.name)
def analyze_block(block, context, routines):
@ -150,9 +162,8 @@ def analyze_instr(instr, context, routines):
raise TypeMismatchError((src, dest))
elif src.type != dest.type:
raise TypeMismatchError((src, dest))
context.assert_initialized(src)
context.assert_writeable(dest, FLAG_Z, FLAG_N)
context.set_initialized(dest, FLAG_Z, FLAG_N)
context.assert_meaningful(src)
context.set_written(dest, FLAG_Z, FLAG_N)
elif opcode == 'st':
if instr.index:
if src.type == TYPE_BYTE and dest.type == TYPE_BYTE_TABLE:
@ -161,49 +172,44 @@ def analyze_instr(instr, context, routines):
raise TypeMismatchError((src, dest))
elif src.type != dest.type:
raise TypeMismatchError((src, dest))
context.assert_initialized(src)
context.assert_writeable(dest)
context.set_initialized(dest)
context.assert_meaningful(src)
context.set_written(dest)
elif opcode in ('add', 'sub'):
context.assert_initialized(src, dest, FLAG_C)
context.assert_writeable(dest, FLAG_Z, FLAG_N, FLAG_C, FLAG_V)
context.set_initialized(dest, FLAG_Z, FLAG_N, FLAG_C, FLAG_V)
context.assert_meaningful(src, dest, FLAG_C)
context.set_written(dest, FLAG_Z, FLAG_N, FLAG_C, FLAG_V)
elif opcode in ('inc', 'dec'):
context.assert_initialized(dest)
context.assert_writeable(dest, FLAG_Z, FLAG_N)
context.set_initialized(dest, FLAG_Z, FLAG_N)
context.assert_meaningful(dest)
context.set_written(dest, FLAG_Z, FLAG_N)
elif opcode == 'cmp':
context.assert_initialized(src, dest)
context.assert_writeable(FLAG_Z, FLAG_N, FLAG_C)
context.set_initialized(FLAG_Z, FLAG_N, FLAG_C)
context.assert_meaningful(src, dest)
context.set_written(FLAG_Z, FLAG_N, FLAG_C)
elif opcode in ('and', 'or', 'xor'):
context.assert_initialized(src, dest)
context.assert_writeable(dest, FLAG_Z, FLAG_N)
context.set_initialized(dest, FLAG_Z, FLAG_N)
context.assert_meaningful(src, dest)
context.set_written(dest, FLAG_Z, FLAG_N)
elif opcode in ('shl', 'shr'):
context.assert_initialized(dest, FLAG_C)
context.assert_writeable(dest, FLAG_Z, FLAG_N, FLAG_C)
context.set_initialized(dest, FLAG_Z, FLAG_N, FLAG_C)
context.assert_meaningful(dest, FLAG_C)
context.set_written(dest, FLAG_Z, FLAG_N, FLAG_C)
elif opcode == 'call':
routine = routines[instr.name]
for ref in routine.inputs:
context.assert_initialized(ref)
context.assert_meaningful(ref)
for ref in routine.outputs:
context.assert_writeable(ref)
context.set_initialized(ref)
context.set_written(ref)
for ref in routine.trashes:
context.assert_writeable(ref)
context.set_uninitialized(ref)
context.set_touched(ref)
context.set_unmeaningful(ref)
elif opcode == 'if':
context1 = context.clone()
context2 = context.clone()
analyze_block(instr.block1, context1, routines)
if instr.block2 is not None:
analyze_block(instr.block2, context2, routines)
for ref in context1.each_initialized():
context2.assert_initialized(ref, exception_class=InconsistentInitializationError)
for ref in context2.each_initialized():
context1.assert_initialized(ref, exception_class=InconsistentInitializationError)
# TODO may we need to deal with touched separately here too?
for ref in context1.each_meaningful():
context2.assert_meaningful(ref, exception_class=InconsistentInitializationError)
for ref in context2.each_meaningful():
context1.assert_meaningful(ref, exception_class=InconsistentInitializationError)
context.set_from(context1)
elif opcode == 'repeat':
# it will always be executed at least once, so analyze it having
@ -222,9 +228,9 @@ def analyze_instr(instr, context, routines):
pass
else:
raise TypeMismatchError((src, dest))
context.assert_initialized(src)
context.assert_writeable(dest)
context.set_initialized(dest)
context.set_uninitialized(REG_A, FLAG_Z, FLAG_N)
context.assert_meaningful(src)
context.set_written(dest)
context.set_touched(REG_A, FLAG_Z, FLAG_N)
context.set_unmeaningful(REG_A, FLAG_Z, FLAG_N)
else:
raise NotImplementedError(opcode)