def get_value(history, instr):
if fmt == 'S+xI':
return buildExpr(op, history.read(instr.sourceReg,
basicTypes.word),
algebra.Literal(instr.immediate))
elif fmt == 'S+I':
return buildExpr(op, history.read(instr.sourceReg,
basicTypes.word),
algebra.Literal(extend(instr.immediate)))
elif fmt == 'f(I)':
return algebra.Literal(op(instr.immediate))
elif fmt == 'F+F':
return buildExpr(op,
history.read(instr.fs, basicTypes.single),
history.read(instr.ft, basicTypes.single),
flop=True)
elif fmt == '@F':
if op == 'id':
return history.read(instr.fs)
else:
return buildExpr('@', op, history.read(instr.fs))
elif fmt == 'T<<A':
return buildExpr(op, history.read(instr.targetReg,
basicTypes.word),
algebra.Literal(instr.shift))
elif fmt == 'S+T':
return buildExpr(op, history.read(instr.sourceReg,
basicTypes.word),
history.read(instr.targetReg, basicTypes.word))
elif fmt == 'T<<S':
return buildExpr(op, history.read(instr.targetReg,
basicTypes.word),
history.read(instr.sourceReg, basicTypes.word))
raise Error("Bad format")
def subLookup(self, fmt, base, address, others=[]):
"""Recursively find data at the given address from the start of a type"""
if isinstance(base.type, basicTypes.Array):
spacing = self.getSize(base.type.pointedType)
index = algebra.Literal(address // spacing)
canIndex = True
for o in others:
if (isinstance(o, algebra.Expression) and o.op == '*'
and o.constant and o.constant.value == spacing):
index = buildExpr(
'+', index,
algebra.Expression.arithmeticMerge('*', o.args))
else:
canIndex = False
break
if canIndex:
element = buildExpr('[', base, index)
if basicTypes.isIndexable(base.type.pointedType):
return self.subLookup(fmt, element, address % spacing)
else:
return element
else:
return buildExpr(
'@', fmt,
algebra.Expression.arithmeticMerge(
'+', [base, algebra.Literal(address)] + others))
parentStruct = None
if isinstance(base.type, basicTypes.Pointer):
parentStruct = base.type.pointedType
elif isinstance(base.type, str):
parentStruct = base.type
if parentStruct and parentStruct in self.bindings['structs']:
members = self.bindings['structs'][parentStruct].members
try:
bestOffset = max(x for x in members if x <= address)
except ValueError: # nothing less
pass
else:
newBase = buildExpr('.', base,
algebra.Symbol(*members[bestOffset]))
if address < bestOffset + self.getSize(newBase.type):
if basicTypes.isIndexable(newBase.type):
return self.subLookup(fmt, newBase,
address - bestOffset, others)
if not others:
#TODO account for reading the lower short of a word, etc.
return newBase
if others:
return buildExpr(
'@', fmt,
algebra.arithmeticMerge(
'+', [base, algebra.Literal(address)] + others))
else:
return buildExpr(
'.', base,
algebra.Symbol(
'{}_{:#x}'.format(basicTypes.getCode(fmt), address), fmt))
def foo(instr, history):
if instr.sourceReg == Register.SP:
return InstrResult.register, history.write(basicTypes.Stack(extend(instr.immediate)),
history.read(instr.targetReg, datatype))
else:
dest = history.lookupAddress(datatype, buildExpr('+',
history.read(instr.sourceReg, basicTypes.address),
algebra.Literal(extend(instr.immediate))))
return InstrResult.write, history.read(instr.targetReg, dest.type), dest
def foo(instr, history):
if instr.sourceReg == Register.SP:
#TODO account for more general reads (ie, just the lower bytes of a word)
value = history.read(basicTypes.Stack(extend(instr.immediate)), datatype)
else:
address = buildExpr('+', history.read(instr.sourceReg, basicTypes.address),
algebra.Literal(extend(instr.immediate)))
value = history.lookupAddress(datatype, address)
return InstrResult.register, history.write(instr.targetReg, value)
def __init__(self, bindings, args=[]):
self.states = defaultdict(list)
self.bindings = bindings
self.argList = [] #arguments beyond the given ones
self.now = Context([Branch()])
self.write(Register.R0, algebra.Literal(0))
self.write(Register.SP, algebra.Symbol('SP'))
self.write(Register.RA, algebra.Symbol('RA'))
self.write(SpecialRegister.Compare, algebra.Symbol('bad_CC'))
for reg, name, fmt in args:
showName = name if name else VariableHistory.getName(reg)
self.argList.append(reg)
self.write(reg, algebra.Symbol(showName, fmt))
def read(self, var, fmt=basicTypes.unknown):
"""Retrive (an appropriate representation of) the value in a register and track its usage
var should be a register or Stack() object
Depending on the expected format, the stored value may be altered substantially
"""
if var == Register.R0: #zero is zero, shouldn't remember type info
return algebra.Literal(0)
if var in self.states:
uncertain = False
for st in reversed(self.states[var]):
if self.now.implies(
st.context)[0]: # this state definitely occurred
if uncertain:
st.explicit = True
break
else:
if isinstance(st.value, algebra.Literal):
if isinstance(fmt, basicTypes.EnumType):
st.value = self.getEnumValue(
fmt, st.value.value)
elif basicTypes.isIndexable(fmt):
st.value = self.lookupAddress(fmt, st.value)
elif st.value.type in [
basicTypes.unknown, basicTypes.bad
]:
st.value.type = fmt
return st.value
elif self.now.isCompatibleWith(st.context):
st.explicit = True
uncertain = True
return algebra.Symbol(VariableHistory.getName(var), fmt)
else:
symName = VariableHistory.getName(var)
if VariableHistory.couldBeArg(var):
self.argList.append(var)
symName = 'arg_' + symName
self.states[var].append(
VariableState(self.getName(var), algebra.Symbol(symName, fmt),
self.now))
return self.states[var][-1].value
