Mercurial > lcfOS
view python/c3/typecheck.py @ 228:7f18ed9b6b7e
Removal of emptystatement class
author | Windel Bouwman |
---|---|
date | Sat, 13 Jul 2013 11:12:24 +0200 |
parents | 82dfe6a32717 |
children | 88a1e0baef65 |
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from .astnodes import * from .scope import * from .visitor import Visitor def equalTypes(a, b): """ Compare types a and b for equality. Not equal until proven otherwise. """ # Recurse into named types: if type(a) is DefinedType: return equalTypes(a.typ, b) if type(b) is DefinedType: return equalTypes(a, b.typ) # 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): if isinstance(fromT, PointerType) and isinstance(toT, PointerType): return True elif fromT is intType and isinstance(toT, PointerType): return True return False 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): self.error('Condition must be of type {0}'.format(boolType), sym.condition.loc) elif type(sym) is Assignment: if not equalTypes(sym.lval.typ, sym.rval.typ): self.error('Cannot assign {0} to {1}'.format(sym.rval.typ, sym.lval.typ), sym.loc) if not sym.lval.lvalue: self.error('No valid lvalue {}'.format(sym.lval), sym.lval.loc) #if sym.rval.lvalue: # self.error('Right hand side must be an rvalue', sym.rval.loc) 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): 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 = sym.ptr.typ if type(ptype) is DefinedType: ptype = ptype.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 = True if type(basetype) is DefinedType: basetype = basetype.typ 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 ['+', '-', '*', '/']: 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) elif sym.op in ['|', '&']: sym.typ = intType sym.lvalue = False if equalTypes(sym.a.typ, sym.b.typ): if not equalTypes(sym.a.typ, intType): self.error('Can only add integers', sym.loc) else: self.error('Types unequal {} != {}'.format(sym.a.typ, sym.b.typ), sym.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)) 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))