JezK
Edit File: symbols.py
"""Module symbol-table generator""" from compiler import ast from compiler.consts import SC_LOCAL, SC_GLOBAL_IMPLICIT, SC_GLOBAL_EXPLICIT, \ SC_FREE, SC_CELL, SC_UNKNOWN from compiler.misc import mangle import types import sys MANGLE_LEN = 256 class Scope: # XXX how much information do I need about each name? def __init__(self, name, module, klass=None): self.name = name self.module = module self.defs = {} self.uses = {} self.globals = {} self.params = {} self.frees = {} self.cells = {} self.children = [] # nested is true if the class could contain free variables, # i.e. if it is nested within another function. self.nested = None self.generator = None self.klass = None if klass is not None: for i in range(len(klass)): if klass[i] != '_': self.klass = klass[i:] break def __repr__(self): return "<%s: %s>" % (self.__class__.__name__, self.name) def mangle(self, name): if self.klass is None: return name return mangle(name, self.klass) def add_def(self, name): self.defs[self.mangle(name)] = 1 def add_use(self, name): self.uses[self.mangle(name)] = 1 def add_global(self, name): name = self.mangle(name) if name in self.uses or name in self.defs: pass # XXX warn about global following def/use if name in self.params: raise SyntaxError, "%s in %s is global and parameter" % \ (name, self.name) self.globals[name] = 1 self.module.add_def(name) def add_param(self, name): name = self.mangle(name) self.defs[name] = 1 self.params[name] = 1 def get_names(self): d = {} d.update(self.defs) d.update(self.uses) d.update(self.globals) return d.keys() def add_child(self, child): self.children.append(child) def get_children(self): return self.children def DEBUG(self): print >> sys.stderr, self.name, self.nested and "nested" or "" print >> sys.stderr, "\tglobals: ", self.globals print >> sys.stderr, "\tcells: ", self.cells print >> sys.stderr, "\tdefs: ", self.defs print >> sys.stderr, "\tuses: ", self.uses print >> sys.stderr, "\tfrees:", self.frees def check_name(self, name): """Return scope of name. The scope of a name could be LOCAL, GLOBAL, FREE, or CELL. """ if name in self.globals: return SC_GLOBAL_EXPLICIT if name in self.cells: return SC_CELL if name in self.defs: return SC_LOCAL if self.nested and (name in self.frees or name in self.uses): return SC_FREE if self.nested: return SC_UNKNOWN else: return SC_GLOBAL_IMPLICIT def get_free_vars(self): if not self.nested: return () free = {} free.update(self.frees) for name in self.uses.keys(): if name not in self.defs and name not in self.globals: free[name] = 1 return free.keys() def handle_children(self): for child in self.children: frees = child.get_free_vars() globals = self.add_frees(frees) for name in globals: child.force_global(name) def force_global(self, name): """Force name to be global in scope. Some child of the current node had a free reference to name. When the child was processed, it was labelled a free variable. Now that all its enclosing scope have been processed, the name is known to be a global or builtin. So walk back down the child chain and set the name to be global rather than free. Be careful to stop if a child does not think the name is free. """ self.globals[name] = 1 if name in self.frees: del self.frees[name] for child in self.children: if child.check_name(name) == SC_FREE: child.force_global(name) def add_frees(self, names): """Process list of free vars from nested scope. Returns a list of names that are either 1) declared global in the parent or 2) undefined in a top-level parent. In either case, the nested scope should treat them as globals. """ child_globals = [] for name in names: sc = self.check_name(name) if self.nested: if sc == SC_UNKNOWN or sc == SC_FREE \ or isinstance(self, ClassScope): self.frees[name] = 1 elif sc == SC_GLOBAL_IMPLICIT: child_globals.append(name) elif isinstance(self, FunctionScope) and sc == SC_LOCAL: self.cells[name] = 1 elif sc != SC_CELL: child_globals.append(name) else: if sc == SC_LOCAL: self.cells[name] = 1 elif sc != SC_CELL: child_globals.append(name) return child_globals def get_cell_vars(self): return self.cells.keys() class ModuleScope(Scope): __super_init = Scope.__init__ def __init__(self): self.__super_init("global", self) class FunctionScope(Scope): pass class GenExprScope(Scope): __super_init = Scope.__init__ __counter = 1 def __init__(self, module, klass=None): i = self.__counter self.__counter += 1 self.__super_init("generator expression<%d>"%i, module, klass) self.add_param('.0') def get_names(self): keys = Scope.get_names(self) return keys class LambdaScope(FunctionScope): __super_init = Scope.__init__ __counter = 1 def __init__(self, module, klass=None): i = self.__counter self.__counter += 1 self.__super_init("lambda.%d" % i, module, klass) class ClassScope(Scope): __super_init = Scope.__init__ def __init__(self, name, module): self.__super_init(name, module, name) class SymbolVisitor: def __init__(self): self.scopes = {} self.klass = None # node that define new scopes def visitModule(self, node): scope = self.module = self.scopes[node] = ModuleScope() self.visit(node.node, scope) visitExpression = visitModule def visitFunction(self, node, parent): if node.decorators: self.visit(node.decorators, parent) parent.add_def(node.name) for n in node.defaults: self.visit(n, parent) scope = FunctionScope(node.name, self.module, self.klass) if parent.nested or isinstance(parent, FunctionScope): scope.nested = 1 self.scopes[node] = scope self._do_args(scope, node.argnames) self.visit(node.code, scope) self.handle_free_vars(scope, parent) def visitGenExpr(self, node, parent): scope = GenExprScope(self.module, self.klass); if parent.nested or isinstance(parent, FunctionScope) \ or isinstance(parent, GenExprScope): scope.nested = 1 self.scopes[node] = scope self.visit(node.code, scope) self.handle_free_vars(scope, parent) def visitGenExprInner(self, node, scope): for genfor in node.quals: self.visit(genfor, scope) self.visit(node.expr, scope) def visitGenExprFor(self, node, scope): self.visit(node.assign, scope, 1) self.visit(node.iter, scope) for if_ in node.ifs: self.visit(if_, scope) def visitGenExprIf(self, node, scope): self.visit(node.test, scope) def visitLambda(self, node, parent, assign=0): # Lambda is an expression, so it could appear in an expression # context where assign is passed. The transformer should catch # any code that has a lambda on the left-hand side. assert not assign for n in node.defaults: self.visit(n, parent) scope = LambdaScope(self.module, self.klass) if parent.nested or isinstance(parent, FunctionScope): scope.nested = 1 self.scopes[node] = scope self._do_args(scope, node.argnames) self.visit(node.code, scope) self.handle_free_vars(scope, parent) def _do_args(self, scope, args): for name in args: if type(name) == types.TupleType: self._do_args(scope, name) else: scope.add_param(name) def handle_free_vars(self, scope, parent): parent.add_child(scope) scope.handle_children() def visitClass(self, node, parent): parent.add_def(node.name) for n in node.bases: self.visit(n, parent) scope = ClassScope(node.name, self.module) if parent.nested or isinstance(parent, FunctionScope): scope.nested = 1 if node.doc is not None: scope.add_def('__doc__') scope.add_def('__module__') self.scopes[node] = scope prev = self.klass self.klass = node.name self.visit(node.code, scope) self.klass = prev self.handle_free_vars(scope, parent) # name can be a def or a use # XXX a few calls and nodes expect a third "assign" arg that is # true if the name is being used as an assignment. only # expressions contained within statements may have the assign arg. def visitName(self, node, scope, assign=0): if assign: scope.add_def(node.name) else: scope.add_use(node.name) # operations that bind new names def visitFor(self, node, scope): self.visit(node.assign, scope, 1) self.visit(node.list, scope) self.visit(node.body, scope) if node.else_: self.visit(node.else_, scope) def visitFrom(self, node, scope): for name, asname in node.names: if name == "*": continue scope.add_def(asname or name) def visitImport(self, node, scope): for name, asname in node.names: i = name.find(".") if i > -1: name = name[:i] scope.add_def(asname or name) def visitGlobal(self, node, scope): for name in node.names: scope.add_global(name) def visitAssign(self, node, scope): """Propagate assignment flag down to child nodes. The Assign node doesn't itself contains the variables being assigned to. Instead, the children in node.nodes are visited with the assign flag set to true. When the names occur in those nodes, they are marked as defs. Some names that occur in an assignment target are not bound by the assignment, e.g. a name occurring inside a slice. The visitor handles these nodes specially; they do not propagate the assign flag to their children. """ for n in node.nodes: self.visit(n, scope, 1) self.visit(node.expr, scope) def visitAssName(self, node, scope, assign=1): scope.add_def(node.name) def visitAssAttr(self, node, scope, assign=0): self.visit(node.expr, scope, 0) def visitSubscript(self, node, scope, assign=0): self.visit(node.expr, scope, 0) for n in node.subs: self.visit(n, scope, 0) def visitSlice(self, node, scope, assign=0): self.visit(node.expr, scope, 0) if node.lower: self.visit(node.lower, scope, 0) if node.upper: self.visit(node.upper, scope, 0) def visitAugAssign(self, node, scope): # If the LHS is a name, then this counts as assignment. # Otherwise, it's just use. self.visit(node.node, scope) if isinstance(node.node, ast.Name): self.visit(node.node, scope, 1) # XXX worry about this self.visit(node.expr, scope) # prune if statements if tests are false _const_types = types.StringType, types.IntType, types.FloatType def visitIf(self, node, scope): for test, body in node.tests: if isinstance(test, ast.Const): if type(test.value) in self._const_types: if not test.value: continue self.visit(test, scope) self.visit(body, scope) if node.else_: self.visit(node.else_, scope) # a yield statement signals a generator def visitYield(self, node, scope): scope.generator = 1 self.visit(node.value, scope) def list_eq(l1, l2): return sorted(l1) == sorted(l2) if __name__ == "__main__": import sys from compiler import parseFile, walk import symtable def get_names(syms): return [s for s in [s.get_name() for s in syms.get_symbols()] if not (s.startswith('_[') or s.startswith('.'))] for file in sys.argv[1:]: print file f = open(file) buf = f.read() f.close() syms = symtable.symtable(buf, file, "exec") mod_names = get_names(syms) tree = parseFile(file) s = SymbolVisitor() walk(tree, s) # compare module-level symbols names2 = s.scopes[tree].get_names() if not list_eq(mod_names, names2): print print "oops", file print sorted(mod_names) print sorted(names2) sys.exit(-1) d = {} d.update(s.scopes) del d[tree] scopes = d.values() del d for s in syms.get_symbols(): if s.is_namespace(): l = [sc for sc in scopes if sc.name == s.get_name()] if len(l) > 1: print "skipping", s.get_name() else: if not list_eq(get_names(s.get_namespace()), l[0].get_names()): print s.get_name() print sorted(get_names(s.get_namespace())) print sorted(l[0].get_names()) sys.exit(-1)