Mercurial > lcfOS
view python/c3/typecheck.py @ 240:6259856841a0
Remove project
author | Windel Bouwman |
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date | Mon, 22 Jul 2013 22:37:33 +0200 |
parents | e621e3ba78d2 |
children | c4370696ccc7 |
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from .astnodes import * from .scope import * from .visitor import Visitor def theType(t): """ Recurse until a 'real' type is found """ if type(t) is DefinedType: return theType(t.typ) return t def equalTypes(a, b): """ Compare types a and b for equality. Not equal until proven otherwise. """ # Recurse into named types: a = theType(a) b = theType(b) # Compare for structural equivalence: if type(a) is type(b): if type(a) is BaseType: return a.name == b.name elif type(a) is PointerType: return equalTypes(a.ptype, b.ptype) elif type(a) is StructureType: if len(a.mems) != len(b.mems): return False for amem, bmem in zip(a.mems, b.mems): if not equalTypes(amem.typ, bmem.typ): return False return True else: raise Exception('Type compare not implemented') return False def canCast(fromT, toT): fromT = theType(fromT) toT = theType(toT) if isinstance(fromT, PointerType) and isinstance(toT, PointerType): return True elif fromT is intType and isinstance(toT, PointerType): return True return False def expectRval(s): # TODO: solve this better s.expect_rvalue = True class TypeChecker: def __init__(self, diag): self.diag = diag def error(self, msg, loc): """ Wrapper that registers the message and marks the result invalid """ self.diag.error(msg, loc) self.ok = False def checkPackage(self, pkg): self.ok = True visitor = Visitor() visitor.visit(pkg, f_post=self.check2) return self.ok def check2(self, sym): if type(sym) in [IfStatement, WhileStatement]: if not equalTypes(sym.condition.typ, boolType): msg = 'Condition must be of type {}'.format(boolType) self.error(msg, sym.condition.loc) elif type(sym) is Assignment: l, r = sym.lval, sym.rval if not equalTypes(l.typ, r.typ): msg = 'Cannot assign {} to {}'.format(r.typ, l.typ) self.error(msg, sym.loc) if not l.lvalue: self.error('No valid lvalue {}'.format(l), l.loc) #if sym.rval.lvalue: # self.error('Right hand side must be an rvalue', sym.rval.loc) expectRval(sym.rval) elif type(sym) is ReturnStatement: pass elif type(sym) is FunctionCall: # Check arguments: ngiv = len(sym.args) ptypes = sym.proc.typ.parametertypes nreq = len(ptypes) if ngiv != nreq: self.error('Function {2}: {0} arguments required, {1} given'.format(nreq, ngiv, sym.proc.name), sym.loc) else: for a, at in zip(sym.args, ptypes): expectRval(a) if not equalTypes(a.typ, at): self.error('Got {0}, expected {1}'.format(a.typ, at), a.loc) # determine return type: sym.typ = sym.proc.typ.returntype elif type(sym) is VariableUse: sym.lvalue = True if type(sym.target) is Variable: sym.typ = sym.target.typ else: print('warning {} has no target, defaulting to int'.format(sym)) sym.typ = intType elif type(sym) is Literal: sym.lvalue = False if type(sym.val) is int: sym.typ = intType elif type(sym.val) is float: sym.typ = doubleType elif type(sym.val) is bool: sym.typ = boolType else: raise Exception('Unknown literal type'.format(sym.val)) elif type(sym) is Unop: if sym.op == '&': sym.typ = PointerType(sym.a.typ) sym.lvalue = False else: raise Exception('Unknown unop {0}'.format(sym.op)) elif type(sym) is Deref: # pointer deref sym.lvalue = True # check if the to be dereferenced variable is a pointer type: ptype = theType(sym.ptr.typ) if type(ptype) is PointerType: sym.typ = ptype.ptype else: self.error('Cannot dereference non-pointer type {}'.format(ptype), sym.loc) sym.typ = intType elif type(sym) is FieldRef: basetype = sym.base.typ sym.lvalue = sym.base.lvalue basetype = theType(basetype) if type(basetype) is StructureType: if basetype.hasField(sym.field): sym.typ = basetype.fieldType(sym.field) else: self.error('{} does not contain field {}'.format(basetype, sym.field), sym.loc) sym.typ = intType else: self.error('Cannot select field {} of non-structure type {}'.format(sym.field, basetype), sym.loc) sym.typ = intType elif type(sym) is Binop: sym.lvalue = False if sym.op in ['+', '-', '*', '/', '<<', '>>', '|', '&']: expectRval(sym.a) expectRval(sym.b) if equalTypes(sym.a.typ, sym.b.typ): if equalTypes(sym.a.typ, intType): sym.typ = sym.a.typ else: self.error('Can only add integers', sym.loc) sym.typ = intType else: # assume void here? TODO: throw exception! sym.typ = intType self.error('Types unequal {} != {}'.format(sym.a.typ, sym.b.typ), sym.loc) elif sym.op in ['>', '<', '==', '<=', '>=']: sym.typ = boolType if not equalTypes(sym.a.typ, sym.b.typ): self.error('Types unequal {} != {}'.format(sym.a.typ, sym.b.typ), sym.loc) elif sym.op in ['or', 'and']: sym.typ = boolType if not equalTypes(sym.a.typ, boolType): self.error('Must be {0}'.format(boolType), sym.a.loc) if not equalTypes(sym.b.typ, boolType): self.error('Must be {0}'.format(boolType), sym.b.loc) else: raise Exception('Unknown binop {0}'.format(sym.op)) elif type(sym) is Variable: # check initial value type: # TODO pass elif type(sym) is TypeCast: if canCast(sym.a.typ, sym.to_type): sym.typ = sym.to_type else: self.error('Cannot cast {} to {}'.format(sym.a.typ, sym.to_type), sym.loc) sym.typ = intType elif type(sym) is Constant: if not equalTypes(sym.typ, sym.value.typ): self.error('Cannot assign {0} to {1}'.format(sym.value.typ, sym.typ), sym.loc) elif type(sym) in [CompoundStatement, Package, Function, FunctionType, ExpressionStatement, DefinedType]: pass else: raise Exception('Unknown type check {0}'.format(sym))