blob: 1c804994d4adc2cf8c5156405b5a2c64d1a33220 [file] [log] [blame]
"""Python bytecode generator
Currently contains generic ASTVisitor code, a LocalNameFinder, and a
CodeGenerator. Eventually, this will get split into the ASTVisitor as
a generic tool and CodeGenerator as a specific tool.
"""
from p2c import transformer, ast
from pyassem import StackRef, PyAssembler
import dis
import misc
import marshal
import new
import string
import sys
import os
import stat
import struct
def parse(path):
f = open(path)
src = f.read()
f.close()
t = transformer.Transformer()
return t.parsesuite(src)
def walk(tree, visitor, verbose=None, walker=None):
if walker:
w = walker()
else:
w = ASTVisitor()
if verbose is not None:
w.VERBOSE = verbose
w.preorder(tree, visitor)
return w.visitor
def dumpNode(node):
print node.__class__
for attr in dir(node):
if attr[0] != '_':
print "\t", "%-10.10s" % attr, getattr(node, attr)
class ASTVisitor:
"""Performs a depth-first walk of the AST
The ASTVisitor will walk the AST, performing either a preorder or
postorder traversal depending on which method is called.
methods:
preorder(tree, visitor)
postorder(tree, visitor)
tree: an instance of ast.Node
visitor: an instance with visitXXX methods
The ASTVisitor is responsible for walking over the tree in the
correct order. For each node, it checks the visitor argument for
a method named 'visitNodeType' where NodeType is the name of the
node's class, e.g. Classdef. If the method exists, it is called
with the node as its sole argument.
The visitor method for a particular node type can control how
child nodes are visited during a preorder walk. (It can't control
the order during a postorder walk, because it is called _after_
the walk has occurred.) The ASTVisitor modifies the visitor
argument by adding a visit method to the visitor; this method can
be used to visit a particular child node. If the visitor method
returns a true value, the ASTVisitor will not traverse the child
nodes.
XXX The interface for controlling the preorder walk needs to be
re-considered. The current interface is convenient for visitors
that mostly let the ASTVisitor do everything. For something like
a code generator, where you want to walk to occur in a specific
order, it's a pain to add "return 1" to the end of each method.
XXX Perhaps I can use a postorder walk for the code generator?
"""
VERBOSE = 0
def __init__(self):
self.node = None
def preorder(self, tree, visitor):
"""Do preorder walk of tree using visitor"""
self.visitor = visitor
visitor.visit = self._preorder
self._preorder(tree)
def _preorder(self, node):
stop = self.dispatch(node)
if stop:
return
for child in node.getChildren():
if isinstance(child, ast.Node):
self._preorder(child)
def postorder(self, tree, visitor):
"""Do preorder walk of tree using visitor"""
self.visitor = visitor
visitor.visit = self._postorder
self._postorder(tree)
def _postorder(self, tree):
for child in node.getChildren():
if isinstance(child, ast.Node):
self._preorder(child)
self.dispatch(node)
def dispatch(self, node):
self.node = node
className = node.__class__.__name__
meth = getattr(self.visitor, 'visit' + className, None)
if self.VERBOSE > 0:
if self.VERBOSE == 1:
if meth is None:
print "dispatch", className
else:
print "dispatch", className, (meth and meth.__name__ or '')
if meth:
return meth(node)
class ExampleASTVisitor(ASTVisitor):
"""Prints examples of the nodes that aren't visited"""
examples = {}
def dispatch(self, node):
self.node = node
className = node.__class__.__name__
meth = getattr(self.visitor, 'visit' + className, None)
if self.VERBOSE > 0:
if self.VERBOSE == 1:
if meth is None:
print "dispatch", className
else:
print "dispatch", className, (meth and meth.__name__ or '')
if meth:
return meth(node)
else:
klass = node.__class__
if self.VERBOSE < 2:
if self.examples.has_key(klass):
return
self.examples[klass] = klass
print
print klass
for attr in dir(node):
if attr[0] != '_':
print "\t", "%-12.12s" % attr, getattr(node, attr)
print
class CodeGenerator:
"""TODO
EmptyNode
Sliceobj
Tryexcept
Tryfinally
"""
OPTIMIZED = 1
# XXX should clean up initialization and generateXXX funcs
def __init__(self, filename="<?>"):
self.filename = filename
self.code = PyAssembler()
self.code.setFlags(0)
self.locals = misc.Stack()
self.loops = misc.Stack()
self.namespace = 0
self.curStack = 0
self.maxStack = 0
def emit(self, *args):
# XXX could just use self.emit = self.code.emit
apply(self.code.emit, args)
def _generateFunctionOrLambdaCode(self, func):
self.name = func.name
self.filename = filename
args = func.argnames
self.code = PyAssembler(args=args, name=func.name,
filename=filename)
self.namespace = self.OPTIMIZED
if func.varargs:
self.code.setVarArgs()
if func.kwargs:
self.code.setKWArgs()
lnf = walk(func.code, LocalNameFinder(args), 0)
self.locals.push(lnf.getLocals())
self.emit('SET_LINENO', func.lineno)
walk(func.code, self)
def generateFunctionCode(self, func):
"""Generate code for a function body"""
self._generateFunctionOrLambdaCode(func)
self.emit('LOAD_CONST', None)
self.emit('RETURN_VALUE')
def generateLambdaCode(self, func):
self._generateFunctionOrLambdaCode(func)
self.emit('RETURN_VALUE')
def generateClassCode(self, klass):
self.code = PyAssembler(name=klass.name,
filename=filename)
self.emit('SET_LINENO', klass.lineno)
lnf = walk(klass.code, LocalNameFinder(), 0)
self.locals.push(lnf.getLocals())
walk(klass.code, self)
self.emit('LOAD_LOCALS')
self.emit('RETURN_VALUE')
def asConst(self):
"""Create a Python code object."""
if self.namespace == self.OPTIMIZED:
self.code.setOptimized()
return self.code.makeCodeObject()
def isLocalName(self, name):
return self.locals.top().has_elt(name)
def _nameOp(self, prefix, name):
if self.isLocalName(name):
if self.namespace == self.OPTIMIZED:
self.emit(prefix + '_FAST', name)
else:
self.emit(prefix + '_NAME', name)
else:
self.emit(prefix + '_GLOBAL', name)
def storeName(self, name):
self._nameOp('STORE', name)
def loadName(self, name):
self._nameOp('LOAD', name)
def delName(self, name):
self._nameOp('DELETE', name)
def visitNULL(self, node):
"""Method exists only to stop warning in -v mode"""
pass
visitStmt = visitNULL
visitGlobal = visitNULL
def visitDiscard(self, node):
self.visit(node.expr)
self.emit('POP_TOP')
return 1
def visitPass(self, node):
self.emit('SET_LINENO', node.lineno)
def visitModule(self, node):
lnf = walk(node.node, LocalNameFinder(), 0)
self.locals.push(lnf.getLocals())
self.visit(node.node)
self.emit('LOAD_CONST', None)
self.emit('RETURN_VALUE')
return 1
def visitImport(self, node):
self.emit('SET_LINENO', node.lineno)
for name in node.names:
self.emit('IMPORT_NAME', name)
self.storeName(name)
def visitFrom(self, node):
self.emit('SET_LINENO', node.lineno)
self.emit('IMPORT_NAME', node.modname)
for name in node.names:
if name == '*':
self.namespace = 0
self.emit('IMPORT_FROM', name)
self.emit('POP_TOP')
def visitClassdef(self, node):
self.emit('SET_LINENO', node.lineno)
self.emit('LOAD_CONST', node.name)
for base in node.bases:
self.visit(base)
self.emit('BUILD_TUPLE', len(node.bases))
classBody = CodeGenerator(self.filename)
classBody.generateClassCode(node)
self.emit('LOAD_CONST', classBody)
self.emit('MAKE_FUNCTION', 0)
self.emit('CALL_FUNCTION', 0)
self.emit('BUILD_CLASS')
self.storeName(node.name)
return 1
def _visitFuncOrLambda(self, node, kind):
"""Code common to Function and Lambda nodes"""
codeBody = CodeGenerator(self.filename)
getattr(codeBody, 'generate%sCode' % kind)(node)
self.emit('SET_LINENO', node.lineno)
for default in node.defaults:
self.visit(default)
self.emit('LOAD_CONST', codeBody)
self.emit('MAKE_FUNCTION', len(node.defaults))
def visitFunction(self, node):
self._visitFuncOrLambda(node, 'Function')
self.storeName(node.name)
return 1
def visitLambda(self, node):
node.name = '<lambda>'
node.varargs = node.kwargs = None
self._visitFuncOrLambda(node, 'Lambda')
return 1
def visitCallFunc(self, node):
pos = 0
kw = 0
if hasattr(node, 'lineno'):
self.emit('SET_LINENO', node.lineno)
self.visit(node.node)
for arg in node.args:
self.visit(arg)
if isinstance(arg, ast.Keyword):
kw = kw + 1
else:
pos = pos + 1
self.emit('CALL_FUNCTION', kw << 8 | pos)
return 1
def visitKeyword(self, node):
self.emit('LOAD_CONST', node.name)
self.visit(node.expr)
return 1
def visitIf(self, node):
after = StackRef()
for test, suite in node.tests:
if hasattr(test, 'lineno'):
self.emit('SET_LINENO', test.lineno)
else:
print "warning", "no line number"
self.visit(test)
dest = StackRef()
self.emit('JUMP_IF_FALSE', dest)
self.emit('POP_TOP')
self.visit(suite)
self.emit('JUMP_FORWARD', after)
dest.bind(self.code.getCurInst())
self.emit('POP_TOP')
if node.else_:
self.visit(node.else_)
after.bind(self.code.getCurInst())
return 1
def startLoop(self):
l = Loop()
self.loops.push(l)
self.emit('SETUP_LOOP', l.extentAnchor)
return l
def finishLoop(self):
l = self.loops.pop()
i = self.code.getCurInst()
l.extentAnchor.bind(self.code.getCurInst())
def visitFor(self, node):
# three refs needed
anchor = StackRef()
self.emit('SET_LINENO', node.lineno)
l = self.startLoop()
self.visit(node.list)
self.visit(ast.Const(0))
l.startAnchor.bind(self.code.getCurInst())
self.emit('SET_LINENO', node.lineno)
self.emit('FOR_LOOP', anchor)
self.visit(node.assign)
self.visit(node.body)
self.emit('JUMP_ABSOLUTE', l.startAnchor)
anchor.bind(self.code.getCurInst())
self.emit('POP_BLOCK')
if node.else_:
self.visit(node.else_)
self.finishLoop()
return 1
def visitWhile(self, node):
self.emit('SET_LINENO', node.lineno)
l = self.startLoop()
if node.else_:
lElse = StackRef()
else:
lElse = l.breakAnchor
l.startAnchor.bind(self.code.getCurInst())
self.emit('SET_LINENO', node.test.lineno)
self.visit(node.test)
self.emit('JUMP_IF_FALSE', lElse)
self.emit('POP_TOP')
self.visit(node.body)
self.emit('JUMP_ABSOLUTE', l.startAnchor)
# note that lElse may be an alias for l.breakAnchor
lElse.bind(self.code.getCurInst())
self.emit('POP_TOP')
self.emit('POP_BLOCK')
if node.else_:
self.visit(node.else_)
self.finishLoop()
return 1
def visitBreak(self, node):
if not self.loops:
raise SyntaxError, "'break' outside loop"
self.emit('SET_LINENO', node.lineno)
self.emit('BREAK_LOOP')
def visitContinue(self, node):
if not self.loops:
raise SyntaxError, "'continue' outside loop"
l = self.loops.top()
self.emit('SET_LINENO', node.lineno)
self.emit('JUMP_ABSOLUTE', l.startAnchor)
def visitCompare(self, node):
"""Comment from compile.c follows:
The following code is generated for all but the last
comparison in a chain:
label: on stack: opcode: jump to:
a <code to load b>
a, b DUP_TOP
a, b, b ROT_THREE
b, a, b COMPARE_OP
b, 0-or-1 JUMP_IF_FALSE L1
b, 1 POP_TOP
b
We are now ready to repeat this sequence for the next
comparison in the chain.
For the last we generate:
b <code to load c>
b, c COMPARE_OP
0-or-1
If there were any jumps to L1 (i.e., there was more than one
comparison), we generate:
0-or-1 JUMP_FORWARD L2
L1: b, 0 ROT_TWO
0, b POP_TOP
0
L2: 0-or-1
"""
self.visit(node.expr)
# if refs are never emitted, subsequent bind call has no effect
l1 = StackRef()
l2 = StackRef()
for op, code in node.ops[:-1]:
# emit every comparison except the last
self.visit(code)
self.emit('DUP_TOP')
self.emit('ROT_THREE')
self.emit('COMPARE_OP', op)
# dupTop and compareOp cancel stack effect
self.emit('JUMP_IF_FALSE', l1)
self.emit('POP_TOP')
if node.ops:
# emit the last comparison
op, code = node.ops[-1]
self.visit(code)
self.emit('COMPARE_OP', op)
if len(node.ops) > 1:
self.emit('JUMP_FORWARD', l2)
l1.bind(self.code.getCurInst())
self.emit('ROT_TWO')
self.emit('POP_TOP')
l2.bind(self.code.getCurInst())
return 1
def visitGetattr(self, node):
self.visit(node.expr)
self.emit('LOAD_ATTR', node.attrname)
return 1
def visitSubscript(self, node):
self.visit(node.expr)
for sub in node.subs[:-1]:
self.visit(sub)
self.emit('BINARY_SUBSCR')
self.visit(node.subs[-1])
if node.flags == 'OP_APPLY':
self.emit('BINARY_SUBSCR')
elif node.flags == 'OP_ASSIGN':
self.emit('STORE_SUBSCR')
elif node.flags == 'OP_DELETE':
self.emit('DELETE_SUBSCR')
return 1
def visitSlice(self, node):
self.visit(node.expr)
slice = 0
if node.lower:
self.visit(node.lower)
slice = slice | 1
if node.upper:
self.visit(node.upper)
slice = slice | 2
if node.flags == 'OP_APPLY':
self.emit('SLICE+%d' % slice)
elif node.flags == 'OP_ASSIGN':
self.emit('STORE_SLICE+%d' % slice)
elif node.flags == 'OP_DELETE':
self.emit('DELETE_SLICE+%d' % slice)
else:
print node.flags
raise
return 1
def visitAssign(self, node):
self.emit('SET_LINENO', node.lineno)
self.visit(node.expr)
dups = len(node.nodes) - 1
for i in range(len(node.nodes)):
elt = node.nodes[i]
if i < dups:
self.emit('DUP_TOP')
if isinstance(elt, ast.Node):
self.visit(elt)
return 1
def visitAssName(self, node):
if node.flags != 'OP_ASSIGN':
print "oops", node.flags
self.storeName(node.name)
def visitAssAttr(self, node):
if node.flags != 'OP_ASSIGN':
print "warning: unexpected flags:", node.flags
print node
self.visit(node.expr)
self.emit('STORE_ATTR', node.attrname)
return 1
def visitAssTuple(self, node):
self.emit('UNPACK_TUPLE', len(node.nodes))
for child in node.nodes:
self.visit(child)
return 1
visitAssList = visitAssTuple
def binaryOp(self, node, op):
self.visit(node.left)
self.visit(node.right)
self.emit(op)
return 1
def unaryOp(self, node, op):
self.visit(node.expr)
self.emit(op)
return 1
def visitAdd(self, node):
return self.binaryOp(node, 'BINARY_ADD')
def visitSub(self, node):
return self.binaryOp(node, 'BINARY_SUBTRACT')
def visitMul(self, node):
return self.binaryOp(node, 'BINARY_MULTIPLY')
def visitDiv(self, node):
return self.binaryOp(node, 'BINARY_DIVIDE')
def visitMod(self, node):
return self.binaryOp(node, 'BINARY_MODULO')
def visitPower(self, node):
return self.binaryOp(node, 'BINARY_POWER')
def visitLeftShift(self, node):
return self.binaryOp(node, 'BINARY_LSHIFT')
def visitRightShift(self, node):
return self.binaryOp(node, 'BINARY_RSHIFT')
def visitInvert(self, node):
return self.unaryOp(node, 'UNARY_INVERT')
def visitUnarySub(self, node):
return self.unaryOp(node, 'UNARY_NEGATIVE')
def visitUnaryAdd(self, node):
return self.unaryOp(node, 'UNARY_POSITIVE')
def visitUnaryInvert(self, node):
return self.unaryOp(node, 'UNARY_INVERT')
def visitNot(self, node):
return self.unaryOp(node, 'UNARY_NOT')
def visitBackquote(self, node):
return self.unaryOp(node, 'UNARY_CONVERT')
def bitOp(self, nodes, op):
self.visit(nodes[0])
for node in nodes[1:]:
self.visit(node)
self.emit(op)
return 1
def visitBitand(self, node):
return self.bitOp(node.nodes, 'BINARY_AND')
def visitBitor(self, node):
return self.bitOp(node.nodes, 'BINARY_OR')
def visitBitxor(self, node):
return self.bitOp(node.nodes, 'BINARY_XOR')
def visitTest(self, node, jump):
end = StackRef()
for child in node.nodes[:-1]:
self.visit(child)
self.emit(jump, end)
self.emit('POP_TOP')
self.visit(node.nodes[-1])
end.bind(self.code.getCurInst())
return 1
def visitAssert(self, node):
# XXX __debug__ and AssertionError appear to be special cases
# -- they are always loaded as globals even if there are local
# names. I guess this is a sort of renaming op.
skip = StackRef()
self.emit('SET_LINENO', node.lineno)
self.emit('LOAD_GLOBAL', '__debug__')
self.emit('JUMP_IF_FALSE', skip)
self.emit('POP_TOP')
self.visit(node.test)
self.emit('JUMP_IF_TRUE', skip)
self.emit('LOAD_GLOBAL', 'AssertionError')
self.visit(node.fail)
self.emit('RAISE_VARARGS', 2)
skip.bind(self.code.getCurInst())
self.emit('POP_TOP')
return 1
def visitAnd(self, node):
return self.visitTest(node, 'JUMP_IF_FALSE')
def visitOr(self, node):
return self.visitTest(node, 'JUMP_IF_TRUE')
def visitName(self, node):
self.loadName(node.name)
def visitConst(self, node):
self.emit('LOAD_CONST', node.value)
return 1
def visitEllipsis(self, node):
self.emit('LOAD_CONST', Ellipsis)
return 1
def visitTuple(self, node):
for elt in node.nodes:
self.visit(elt)
self.emit('BUILD_TUPLE', len(node.nodes))
return 1
def visitList(self, node):
for elt in node.nodes:
self.visit(elt)
self.emit('BUILD_LIST', len(node.nodes))
return 1
def visitDict(self, node):
self.emit('BUILD_MAP', 0)
for k, v in node.items:
# XXX need to add set lineno when there aren't constants
self.emit('DUP_TOP')
self.visit(v)
self.emit('ROT_TWO')
self.visit(k)
self.emit('STORE_SUBSCR')
return 1
def visitReturn(self, node):
self.emit('SET_LINENO', node.lineno)
self.visit(node.value)
self.emit('RETURN_VALUE')
return 1
def visitRaise(self, node):
self.emit('SET_LINENO', node.lineno)
n = 0
if node.expr1:
self.visit(node.expr1)
n = n + 1
if node.expr2:
self.visit(node.expr2)
n = n + 1
if node.expr3:
self.visit(node.expr3)
n = n + 1
self.emit('RAISE_VARARGS', n)
return 1
def visitPrint(self, node):
self.emit('SET_LINENO', node.lineno)
for child in node.nodes:
self.visit(child)
self.emit('PRINT_ITEM')
return 1
def visitPrintnl(self, node):
self.visitPrint(node)
self.emit('PRINT_NEWLINE')
return 1
def visitExec(self, node):
self.visit(node.expr)
if node.locals is None:
self.emit('LOAD_CONST', None)
else:
self.visit(node.locals)
if node.globals is None:
self.emit('DUP_TOP')
else:
self.visit(node.globals)
self.emit('EXEC_STMT')
class LocalNameFinder:
def __init__(self, names=()):
self.names = misc.Set()
self.globals = misc.Set()
for name in names:
self.names.add(name)
def getLocals(self):
for elt in self.globals.items():
if self.names.has_elt(elt):
self.names.remove(elt)
return self.names
def visitDict(self, node):
return 1
def visitGlobal(self, node):
for name in node.names:
self.globals.add(name)
return 1
def visitFunction(self, node):
self.names.add(node.name)
return 1
def visitLambda(self, node):
return 1
def visitImport(self, node):
for name in node.names:
self.names.add(name)
def visitFrom(self, node):
for name in node.names:
self.names.add(name)
def visitClassdef(self, node):
self.names.add(node.name)
return 1
def visitAssName(self, node):
self.names.add(node.name)
class Loop:
def __init__(self):
self.startAnchor = StackRef()
self.breakAnchor = StackRef()
self.extentAnchor = StackRef()
class CompiledModule:
"""Store the code object for a compiled module
XXX Not clear how the code objects will be stored. Seems possible
that a single code attribute is sufficient, because it will
contains references to all the need code objects. That might be
messy, though.
"""
MAGIC = (20121 | (ord('\r')<<16) | (ord('\n')<<24))
def __init__(self, source, filename):
self.source = source
self.filename = filename
def compile(self):
t = transformer.Transformer()
self.ast = t.parsesuite(self.source)
cg = CodeGenerator(self.filename)
walk(self.ast, cg, walker=ExampleASTVisitor)
self.code = cg.asConst()
def dump(self, path):
"""create a .pyc file"""
f = open(path, 'wb')
f.write(self._pyc_header())
marshal.dump(self.code, f)
f.close()
def _pyc_header(self):
# compile.c uses marshal to write a long directly, with
# calling the interface that would also generate a 1-byte code
# to indicate the type of the value. simplest way to get the
# same effect is to call marshal and then skip the code.
magic = marshal.dumps(self.MAGIC)[1:]
mtime = os.stat(self.filename)[stat.ST_MTIME]
mtime = struct.pack('i', mtime)
return magic + mtime
if __name__ == "__main__":
import getopt
opts, args = getopt.getopt(sys.argv[1:], 'vq')
for k, v in opts:
if k == '-v':
ASTVisitor.VERBOSE = ASTVisitor.VERBOSE + 1
print k
if k == '-q':
f = open('/dev/null', 'wb')
sys.stdout = f
if args:
filename = args[0]
else:
filename = 'test.py'
buf = open(filename).read()
mod = CompiledModule(buf, filename)
mod.compile()
mod.dump(filename + 'c')