mirror of https://github.com/python/cpython
481 lines
15 KiB
Python
481 lines
15 KiB
Python
"""Assembler for Python bytecode
|
|
|
|
The new module is used to create the code object. The following
|
|
attribute definitions are included from the reference manual:
|
|
|
|
co_name gives the function name
|
|
co_argcount is the number of positional arguments (including
|
|
arguments with default values)
|
|
co_nlocals is the number of local variables used by the function
|
|
(including arguments)
|
|
co_varnames is a tuple containing the names of the local variables
|
|
(starting with the argument names)
|
|
co_code is a string representing the sequence of bytecode instructions
|
|
co_consts is a tuple containing the literals used by the bytecode
|
|
co_names is a tuple containing the names used by the bytecode
|
|
co_filename is the filename from which the code was compiled
|
|
co_firstlineno is the first line number of the function
|
|
co_lnotab is a string encoding the mapping from byte code offsets
|
|
to line numbers. see LineAddrTable below.
|
|
co_stacksize is the required stack size (including local variables)
|
|
co_flags is an integer encoding a number of flags for the
|
|
interpreter. There are four flags:
|
|
CO_OPTIMIZED -- uses load fast
|
|
CO_NEWLOCALS -- everything?
|
|
CO_VARARGS -- use *args
|
|
CO_VARKEYWORDS -- uses **args
|
|
|
|
If a code object represents a function, the first item in co_consts is
|
|
the documentation string of the function, or None if undefined.
|
|
"""
|
|
|
|
import sys
|
|
import dis
|
|
import new
|
|
import string
|
|
|
|
import misc
|
|
|
|
# flags for code objects
|
|
CO_OPTIMIZED = 0x0001
|
|
CO_NEWLOCALS = 0x0002
|
|
CO_VARARGS = 0x0004
|
|
CO_VARKEYWORDS = 0x0008
|
|
|
|
class TupleArg:
|
|
def __init__(self, count, names):
|
|
self.count = count
|
|
self.names = names
|
|
def __repr__(self):
|
|
return "TupleArg(%s, %s)" % (self.count, self.names)
|
|
def getName(self):
|
|
return ".nested%d" % self.count
|
|
|
|
class PyAssembler:
|
|
"""Creates Python code objects
|
|
"""
|
|
|
|
# XXX this class needs to major refactoring
|
|
|
|
def __init__(self, args=(), name='?', filename='<?>',
|
|
docstring=None):
|
|
# XXX why is the default value for flags 3?
|
|
self.insts = []
|
|
# used by makeCodeObject
|
|
self._getArgCount(args)
|
|
self.code = ''
|
|
self.consts = [docstring]
|
|
self.filename = filename
|
|
self.flags = CO_NEWLOCALS
|
|
self.name = name
|
|
self.names = []
|
|
self.varnames = list(args) or []
|
|
for i in range(len(self.varnames)):
|
|
var = self.varnames[i]
|
|
if isinstance(var, TupleArg):
|
|
self.varnames[i] = var.getName()
|
|
# lnotab support
|
|
self.firstlineno = 0
|
|
self.lastlineno = 0
|
|
self.last_addr = 0
|
|
self.lnotab = ''
|
|
|
|
def _getArgCount(self, args):
|
|
self.argcount = len(args)
|
|
if args:
|
|
for arg in args:
|
|
if isinstance(arg, TupleArg):
|
|
numNames = len(misc.flatten(arg.names))
|
|
self.argcount = self.argcount - numNames
|
|
|
|
def __repr__(self):
|
|
return "<bytecode: %d instrs>" % len(self.insts)
|
|
|
|
def setFlags(self, val):
|
|
"""XXX for module's function"""
|
|
self.flags = val
|
|
|
|
def setOptimized(self):
|
|
self.flags = self.flags | CO_OPTIMIZED
|
|
|
|
def setVarArgs(self):
|
|
if not self.flags & CO_VARARGS:
|
|
self.flags = self.flags | CO_VARARGS
|
|
self.argcount = self.argcount - 1
|
|
|
|
def setKWArgs(self):
|
|
self.flags = self.flags | CO_VARKEYWORDS
|
|
|
|
def getCurInst(self):
|
|
return len(self.insts)
|
|
|
|
def getNextInst(self):
|
|
return len(self.insts) + 1
|
|
|
|
def dump(self, io=sys.stdout):
|
|
i = 0
|
|
for inst in self.insts:
|
|
if inst[0] == 'SET_LINENO':
|
|
io.write("\n")
|
|
io.write(" %3d " % i)
|
|
if len(inst) == 1:
|
|
io.write("%s\n" % inst)
|
|
else:
|
|
io.write("%-15.15s\t%s\n" % inst)
|
|
i = i + 1
|
|
|
|
def makeCodeObject(self):
|
|
"""Make a Python code object
|
|
|
|
This creates a Python code object using the new module. This
|
|
seems simpler than reverse-engineering the way marshal dumps
|
|
code objects into .pyc files. One of the key difficulties is
|
|
figuring out how to layout references to code objects that
|
|
appear on the VM stack; e.g.
|
|
3 SET_LINENO 1
|
|
6 LOAD_CONST 0 (<code object fact at 8115878 [...]
|
|
9 MAKE_FUNCTION 0
|
|
12 STORE_NAME 0 (fact)
|
|
"""
|
|
|
|
self._findOffsets()
|
|
lnotab = LineAddrTable()
|
|
for t in self.insts:
|
|
opname = t[0]
|
|
if len(t) == 1:
|
|
lnotab.addCode(self.opnum[opname])
|
|
elif len(t) == 2:
|
|
if opname == 'SET_LINENO':
|
|
oparg = t[1]
|
|
lnotab.nextLine(oparg)
|
|
else:
|
|
oparg = self._convertArg(opname, t[1])
|
|
try:
|
|
hi, lo = divmod(oparg, 256)
|
|
except TypeError:
|
|
raise TypeError, "untranslated arg: %s, %s" % (opname, oparg)
|
|
lnotab.addCode(self.opnum[opname], lo, hi)
|
|
|
|
# why is a module a special case?
|
|
if self.flags == 0:
|
|
nlocals = 0
|
|
else:
|
|
nlocals = len(self.varnames)
|
|
# XXX danger! can't pass through here twice
|
|
if self.flags & CO_VARKEYWORDS:
|
|
self.argcount = self.argcount - 1
|
|
stacksize = findDepth(self.insts)
|
|
try:
|
|
co = new.code(self.argcount, nlocals, stacksize,
|
|
self.flags, lnotab.getCode(), self._getConsts(),
|
|
tuple(self.names), tuple(self.varnames),
|
|
self.filename, self.name, self.firstlineno,
|
|
lnotab.getTable())
|
|
except SystemError, err:
|
|
print err
|
|
print repr(self.argcount)
|
|
print repr(nlocals)
|
|
print repr(stacksize)
|
|
print repr(self.flags)
|
|
print repr(lnotab.getCode())
|
|
print repr(self._getConsts())
|
|
print repr(self.names)
|
|
print repr(self.varnames)
|
|
print repr(self.filename)
|
|
print repr(self.name)
|
|
print repr(self.firstlineno)
|
|
print repr(lnotab.getTable())
|
|
raise
|
|
return co
|
|
|
|
def _getConsts(self):
|
|
"""Return a tuple for the const slot of a code object
|
|
|
|
Converts PythonVMCode objects to code objects
|
|
"""
|
|
l = []
|
|
for elt in self.consts:
|
|
# XXX might be clearer to just as isinstance(CodeGen)
|
|
if hasattr(elt, 'asConst'):
|
|
l.append(elt.asConst())
|
|
else:
|
|
l.append(elt)
|
|
return tuple(l)
|
|
|
|
def _findOffsets(self):
|
|
"""Find offsets for use in resolving StackRefs"""
|
|
self.offsets = []
|
|
cur = 0
|
|
for t in self.insts:
|
|
self.offsets.append(cur)
|
|
l = len(t)
|
|
if l == 1:
|
|
cur = cur + 1
|
|
elif l == 2:
|
|
cur = cur + 3
|
|
arg = t[1]
|
|
# XXX this is a total hack: for a reference used
|
|
# multiple times, we create a list of offsets and
|
|
# expect that we when we pass through the code again
|
|
# to actually generate the offsets, we'll pass in the
|
|
# same order.
|
|
if isinstance(arg, StackRef):
|
|
try:
|
|
arg.__offset.append(cur)
|
|
except AttributeError:
|
|
arg.__offset = [cur]
|
|
|
|
def _convertArg(self, op, arg):
|
|
"""Convert the string representation of an arg to a number
|
|
|
|
The specific handling depends on the opcode.
|
|
|
|
XXX This first implementation isn't going to be very
|
|
efficient.
|
|
"""
|
|
if op == 'SET_LINENO':
|
|
return arg
|
|
if op == 'LOAD_CONST':
|
|
return self._lookupName(arg, self.consts)
|
|
if op in self.localOps:
|
|
# make sure it's in self.names, but use the bytecode offset
|
|
self._lookupName(arg, self.names)
|
|
return self._lookupName(arg, self.varnames)
|
|
if op in self.globalOps:
|
|
return self._lookupName(arg, self.names)
|
|
if op in self.nameOps:
|
|
return self._lookupName(arg, self.names)
|
|
if op == 'COMPARE_OP':
|
|
return self.cmp_op.index(arg)
|
|
if self.hasjrel.has_elt(op):
|
|
offset = arg.__offset[0]
|
|
del arg.__offset[0]
|
|
return self.offsets[arg.resolve()] - offset
|
|
if self.hasjabs.has_elt(op):
|
|
return self.offsets[arg.resolve()]
|
|
return arg
|
|
|
|
nameOps = ('STORE_NAME', 'IMPORT_NAME', 'IMPORT_FROM',
|
|
'STORE_ATTR', 'LOAD_ATTR', 'LOAD_NAME', 'DELETE_NAME',
|
|
'DELETE_ATTR')
|
|
localOps = ('LOAD_FAST', 'STORE_FAST', 'DELETE_FAST')
|
|
globalOps = ('LOAD_GLOBAL', 'STORE_GLOBAL', 'DELETE_GLOBAL')
|
|
|
|
def _lookupName(self, name, list):
|
|
"""Return index of name in list, appending if necessary"""
|
|
if name in list:
|
|
i = list.index(name)
|
|
# this is cheap, but incorrect in some cases, e.g 2 vs. 2L
|
|
if type(name) == type(list[i]):
|
|
return i
|
|
for i in range(len(list)):
|
|
elt = list[i]
|
|
if type(elt) == type(name) and elt == name:
|
|
return i
|
|
end = len(list)
|
|
list.append(name)
|
|
return end
|
|
|
|
# Convert some stuff from the dis module for local use
|
|
|
|
cmp_op = list(dis.cmp_op)
|
|
hasjrel = misc.Set()
|
|
for i in dis.hasjrel:
|
|
hasjrel.add(dis.opname[i])
|
|
hasjabs = misc.Set()
|
|
for i in dis.hasjabs:
|
|
hasjabs.add(dis.opname[i])
|
|
|
|
opnum = {}
|
|
for num in range(len(dis.opname)):
|
|
opnum[dis.opname[num]] = num
|
|
|
|
# this version of emit + arbitrary hooks might work, but it's damn
|
|
# messy.
|
|
|
|
def emit(self, *args):
|
|
self._emitDispatch(args[0], args[1:])
|
|
self.insts.append(args)
|
|
|
|
def _emitDispatch(self, type, args):
|
|
for func in self._emit_hooks.get(type, []):
|
|
func(self, args)
|
|
|
|
_emit_hooks = {}
|
|
|
|
class LineAddrTable:
|
|
"""lnotab
|
|
|
|
This class builds the lnotab, which is undocumented but described
|
|
by com_set_lineno in compile.c. Here's an attempt at explanation:
|
|
|
|
For each SET_LINENO instruction after the first one, two bytes are
|
|
added to lnotab. (In some cases, multiple two-byte entries are
|
|
added.) The first byte is the distance in bytes between the
|
|
instruction for the last SET_LINENO and the current SET_LINENO.
|
|
The second byte is offset in line numbers. If either offset is
|
|
greater than 255, multiple two-byte entries are added -- one entry
|
|
for each factor of 255.
|
|
"""
|
|
|
|
def __init__(self):
|
|
self.code = []
|
|
self.codeOffset = 0
|
|
self.firstline = 0
|
|
self.lastline = 0
|
|
self.lastoff = 0
|
|
self.lnotab = []
|
|
|
|
def addCode(self, *args):
|
|
for arg in args:
|
|
self.code.append(chr(arg))
|
|
self.codeOffset = self.codeOffset + len(args)
|
|
|
|
def nextLine(self, lineno):
|
|
if self.firstline == 0:
|
|
self.firstline = lineno
|
|
self.lastline = lineno
|
|
else:
|
|
# compute deltas
|
|
addr = self.codeOffset - self.lastoff
|
|
line = lineno - self.lastline
|
|
while addr > 0 or line > 0:
|
|
# write the values in 1-byte chunks that sum
|
|
# to desired value
|
|
trunc_addr = addr
|
|
trunc_line = line
|
|
if trunc_addr > 255:
|
|
trunc_addr = 255
|
|
if trunc_line > 255:
|
|
trunc_line = 255
|
|
self.lnotab.append(trunc_addr)
|
|
self.lnotab.append(trunc_line)
|
|
addr = addr - trunc_addr
|
|
line = line - trunc_line
|
|
self.lastline = lineno
|
|
self.lastoff = self.codeOffset
|
|
|
|
def getCode(self):
|
|
return string.join(self.code, '')
|
|
|
|
def getTable(self):
|
|
return string.join(map(chr, self.lnotab), '')
|
|
|
|
class StackRef:
|
|
"""Manage stack locations for jumps, loops, etc."""
|
|
count = 0
|
|
|
|
def __init__(self, id=None, val=None):
|
|
if id is None:
|
|
id = StackRef.count
|
|
StackRef.count = StackRef.count + 1
|
|
self.id = id
|
|
self.val = val
|
|
|
|
def __repr__(self):
|
|
if self.val:
|
|
return "StackRef(val=%d)" % self.val
|
|
else:
|
|
return "StackRef(id=%d)" % self.id
|
|
|
|
def bind(self, inst):
|
|
self.val = inst
|
|
|
|
def resolve(self):
|
|
if self.val is None:
|
|
print "UNRESOLVE REF", self
|
|
return 0
|
|
return self.val
|
|
|
|
class StackDepthTracker:
|
|
# XXX need to keep track of stack depth on jumps
|
|
|
|
def findDepth(self, insts):
|
|
depth = 0
|
|
maxDepth = 0
|
|
for i in insts:
|
|
opname = i[0]
|
|
delta = self.effect.get(opname, 0)
|
|
if delta > 1:
|
|
depth = depth + delta
|
|
elif delta < 0:
|
|
if depth > maxDepth:
|
|
maxDepth = depth
|
|
depth = depth + delta
|
|
else:
|
|
if depth > maxDepth:
|
|
maxDepth = depth
|
|
# now check patterns
|
|
for pat, delta in self.patterns:
|
|
if opname[:len(pat)] == pat:
|
|
depth = depth + delta
|
|
break
|
|
# if we still haven't found a match
|
|
if delta == 0:
|
|
meth = getattr(self, opname)
|
|
depth = depth + meth(i[1])
|
|
if depth < 0:
|
|
depth = 0
|
|
return maxDepth
|
|
|
|
effect = {
|
|
'POP_TOP': -1,
|
|
'DUP_TOP': 1,
|
|
'SLICE+1': -1,
|
|
'SLICE+2': -1,
|
|
'SLICE+3': -2,
|
|
'STORE_SLICE+0': -1,
|
|
'STORE_SLICE+1': -2,
|
|
'STORE_SLICE+2': -2,
|
|
'STORE_SLICE+3': -3,
|
|
'DELETE_SLICE+0': -1,
|
|
'DELETE_SLICE+1': -2,
|
|
'DELETE_SLICE+2': -2,
|
|
'DELETE_SLICE+3': -3,
|
|
'STORE_SUBSCR': -3,
|
|
'DELETE_SUBSCR': -2,
|
|
# PRINT_EXPR?
|
|
'PRINT_ITEM': -1,
|
|
'LOAD_LOCALS': 1,
|
|
'RETURN_VALUE': -1,
|
|
'EXEC_STMT': -2,
|
|
'BUILD_CLASS': -2,
|
|
'STORE_NAME': -1,
|
|
'STORE_ATTR': -2,
|
|
'DELETE_ATTR': -1,
|
|
'STORE_GLOBAL': -1,
|
|
'BUILD_MAP': 1,
|
|
'COMPARE_OP': -1,
|
|
'STORE_FAST': -1,
|
|
}
|
|
# use pattern match
|
|
patterns = [
|
|
('BINARY_', -1),
|
|
('LOAD_', 1),
|
|
('IMPORT_', 1),
|
|
]
|
|
|
|
# special cases:
|
|
# UNPACK_TUPLE, UNPACK_LIST, BUILD_TUPLE,
|
|
# BUILD_LIST, CALL_FUNCTION, MAKE_FUNCTION, BUILD_SLICE
|
|
def UNPACK_TUPLE(self, count):
|
|
return count
|
|
def UNPACK_LIST(self, count):
|
|
return count
|
|
def BUILD_TUPLE(self, count):
|
|
return -count
|
|
def BUILD_LIST(self, count):
|
|
return -count
|
|
def CALL_FUNCTION(self, argc):
|
|
hi, lo = divmod(argc, 256)
|
|
return lo + hi * 2
|
|
def MAKE_FUNCTION(self, argc):
|
|
return -argc
|
|
def BUILD_SLICE(self, argc):
|
|
if argc == 2:
|
|
return -1
|
|
elif argc == 3:
|
|
return -2
|
|
|
|
findDepth = StackDepthTracker().findDepth
|