private static State FindStartState(Machine machine, ITranslationErrorHandler handler)
{
var foundStartState = false;
foreach (State state in machine.AllStates())
{
if (state == machine.StartState || state.IsStart)
{
if (!foundStartState)
{
foundStartState = true;
}
else
{
throw handler.InternalError(state.SourceLocation,
$"Two start states {state.Name} occurs twice in all states list");
}
}
}
if (foundStartState && machine.StartState == null)
{
throw handler.InternalError(machine.SourceLocation, "machine has unregistered start state");
}
if (!foundStartState || machine.StartState == null)
{
// Allow machines with no start state so long as there are no other states.
throw handler.MissingStartState(machine);
}
return(machine.StartState);
}
public override PLanguageType VisitNamedType(PParser.NamedTypeContext context)
{
string typeName = context.name.GetText();
if (scope.Lookup(typeName, out PEnum pEnum))
{
return(new EnumType(pEnum));
}
if (scope.Lookup(typeName, out TypeDef typeDef))
{
if (visitedTypeDefs.Contains(typeDef))
{
throw handler.CircularTypeDef(context.name, typeDef);
}
if (typeDef.Type == null)
{
visitedTypeDefs.Push(typeDef);
switch (typeDef.SourceLocation)
{
case PParser.ForeignTypeDefContext foreignType:
typeDef.Type = new ForeignType(foreignType.name.GetText());
break;
case PParser.PTypeDefContext typedefDecl:
typeDef.Type = Visit(typedefDecl.type());
break;
case InterpreterRuleContext _:
case RuleContextWithAltNum _:
default:
throw handler.InternalError(typeDef.SourceLocation,
new ArgumentOutOfRangeException(nameof(context)));
}
visitedTypeDefs.Pop();
}
return(new TypeDefType(typeDef));
}
if (scope.Lookup(typeName, out NamedEventSet eventSet))
{
return(new PermissionType(eventSet));
}
if (scope.Lookup(typeName, out Interface pInterface))
{
return(new PermissionType(pInterface));
}
if (scope.Lookup(typeName, out Machine machine))
{
return(new PermissionType(machine));
}
throw handler.MissingDeclaration(context.name, "enum, typedef, event set, machine, or interface",
typeName);
}
public override IPExpr VisitKeywordExpr(PParser.KeywordExprContext context)
{
switch (context.fun.Text)
{
case "keys":
{
IPExpr expr = Visit(context.expr());
if (!(expr.Type.Canonicalize() is MapType mapType))
{
throw handler.TypeMismatch(expr, TypeKind.Map);
}
return(new KeysExpr(context, expr, new SequenceType(mapType.KeyType)));
}
case "values":
{
IPExpr expr = Visit(context.expr());
if (!(expr.Type.Canonicalize() is MapType mapType))
{
throw handler.TypeMismatch(expr, TypeKind.Map);
}
return(new ValuesExpr(context, expr, new SequenceType(mapType.ValueType)));
}
case "sizeof":
{
var expr = Visit(context.expr());
if (!(expr.Type.Canonicalize() is SequenceType) &&
!(expr.Type.Canonicalize() is MapType) &&
!(expr.Type.Canonicalize() is SetType))
{
throw handler.TypeMismatch(expr, TypeKind.Map, TypeKind.Sequence, TypeKind.Set);
}
return(new SizeofExpr(context, expr));
}
case "default":
{
PLanguageType type = TypeResolver.ResolveType(context.type(), table, handler);
return(new DefaultExpr(context, type.Canonicalize()));
}
default:
{
throw handler.InternalError(context,
new ArgumentException($"Unknown keyword expression {context.fun.Text}", nameof(context)));
}
}
}
public void CheckWellFormedness(IPModuleExpr moduleExpr)
{
switch (moduleExpr)
{
case AssertModuleExpr assertExpr:
CheckWellFormedness(assertExpr);
break;
case BindModuleExpr bindExpr:
CheckWellFormedness(bindExpr);
break;
case RenameModuleExpr renameExpr:
CheckWellFormedness(renameExpr);
break;
case UnionOrComposeModuleExpr uOrCExpr:
CheckWellFormedness(uOrCExpr);
break;
case HideEventModuleExpr hideEExpr:
CheckWellFormedness(hideEExpr);
break;
case HideInterfaceModuleExpr hideIExpr:
CheckWellFormedness(hideIExpr);
break;
default:
throw handler.InternalError(moduleExpr.SourceLocation,
new ArgumentOutOfRangeException(nameof(moduleExpr)));
}
}
public override PLanguageType VisitNamedType(PParser.NamedTypeContext context)
{
string typeName = context.name.GetText();
if (scope.Lookup(typeName, out PEnum pEnum))
{
return(new EnumType(pEnum));
}
if (scope.Lookup(typeName, out TypeDef typeDef))
{
if (visitedTypeDefs.Contains(typeDef))
{
throw handler.CircularTypeDef(context.name, typeDef);
}
if (typeDef.Type == null)
{
visitedTypeDefs.Add(typeDef);
switch (typeDef.SourceLocation)
{
case PParser.ForeignTypeDefContext foreignType:
typeDef.Type = new ForeignType(foreignType.name.GetText());
break;
case PParser.PTypeDefContext typedefDecl:
typeDef.Type = Visit(typedefDecl.type());
break;
default:
throw handler.InternalError(typeDef.SourceLocation,
$"Grammar changed without updating {nameof(TypeVisitor)}");
}
}
return(new TypeDefType(typeDef));
}
if (scope.Lookup(typeName, out NamedEventSet eventSet))
{
return(new PermissionType(eventSet));
}
if (scope.Lookup(typeName, out Interface pInterface))
{
return(new PermissionType(pInterface));
}
if (scope.Lookup(typeName, out Machine machine))
{
return(new PermissionType(machine));
}
throw handler.MissingDeclaration(context.name, "enum, typedef, event set, machine, or interface", typeName);
}
public static void ValidateNoStaticHandlers(ITranslationErrorHandler handler, Machine machine)
{
foreach (State state in machine.AllStates())
{
bool illegalUsage = state.Entry != null && IsStaticOrForeign(state.Entry);
if (illegalUsage)
{
throw handler.StaticFunctionNotAllowedAsHandler(state.SourceLocation,
state.Entry.Name);
}
illegalUsage = state.Exit != null && IsStaticOrForeign(state.Exit);
if (illegalUsage)
{
throw handler.StaticFunctionNotAllowedAsHandler(state.SourceLocation,
state.Exit.Name);
}
foreach (KeyValuePair <PEvent, AST.IStateAction> pair in state.AllEventHandlers)
{
switch (pair.Value)
{
case EventDoAction eventDoAction:
if (eventDoAction.Target != null && IsStaticOrForeign(eventDoAction.Target))
{
throw handler.StaticFunctionNotAllowedAsHandler(eventDoAction.SourceLocation,
eventDoAction.Target.Name);
}
break;
case EventGotoState eventGotoState:
if (eventGotoState.TransitionFunction != null &&
IsStaticOrForeign(eventGotoState.TransitionFunction))
{
throw handler.StaticFunctionNotAllowedAsHandler(eventGotoState.SourceLocation,
eventGotoState.TransitionFunction.Name);
}
break;
case EventDefer _:
case EventIgnore _:
case EventPushState _:
break;
default:
throw handler.InternalError(pair.Value.SourceLocation,
new System.Exception("Unknown transition type parsed, report to the P team"));
}
}
}
}
private static PLanguageType GetStatePayload(State startState, ITranslationErrorHandler handler)
{
if (!(startState.Entry?.Signature.Parameters.Count > 0))
{
return(PrimitiveType.Null);
}
if (startState.Entry.Signature.Parameters.Count != 1)
{
throw handler.InternalError(startState.OwningMachine.SourceLocation,
"Allowed start state entry with multiple parameters");
}
return(startState.Entry.Signature.Parameters[0].Type);
}
public override IPStmt VisitAssignStmt(PParser.AssignStmtContext context)
{
IPExpr variable = exprVisitor.Visit(context.lvalue());
IPExpr value = exprVisitor.Visit(context.rvalue());
// If we're doing a move/swap assignment
if (value is ILinearRef linearRef)
{
Variable refVariable = linearRef.Variable;
switch (linearRef.LinearType)
{
case LinearType.Move:
// Moved values must be subtypes of their destinations
if (!variable.Type.IsAssignableFrom(refVariable.Type))
{
throw handler.TypeMismatch(context.rvalue(), refVariable.Type, variable.Type);
}
return(new MoveAssignStmt(context, variable, refVariable));
case LinearType.Swap:
// Within a function, swaps must only be subtyped in either direction
// the actual types are checked at runtime. This is to allow swapping
// with the `any` type.
if (!variable.Type.IsAssignableFrom(refVariable.Type) &&
!refVariable.Type.IsAssignableFrom(variable.Type))
{
throw handler.TypeMismatch(context.rvalue(), refVariable.Type, variable.Type);
}
return(new SwapAssignStmt(context, variable, refVariable));
default:
throw handler.InternalError(linearRef.SourceLocation,
new ArgumentOutOfRangeException(nameof(context)));
}
}
// If this is a value assignment, we just need subtyping
if (!variable.Type.IsAssignableFrom(value.Type))
{
throw handler.TypeMismatch(context.rvalue(), value.Type, variable.Type);
}
return(new AssignStmt(context, variable, value));
}
private static void ValidateEventPayloadToTransitionTarget(ITranslationErrorHandler handler,
ParserRuleContext sourceLocation,
PLanguageType eventPayloadType,
Function targetFunction)
{
IReadOnlyList <PLanguageType> entrySignature = targetFunction.Signature.ParameterTypes.ToList();
if (entrySignature.Count == 0)
{
return;
}
if (entrySignature.Count > 1)
{
throw handler.InternalError(sourceLocation, new System.Exception("Target function cannot have multiple parameters (report this to the P developers)"));
}
if (entrySignature.Count == 1 && entrySignature[0].IsAssignableFrom(eventPayloadType))
{
return;
}
if (entrySignature.Count == 1 && eventPayloadType.Canonicalize() is TupleType tuple &&
tuple.Types.Count == 1 && entrySignature[0].IsAssignableFrom(tuple.Types[0]))
{
return;
}
if (entrySignature.Count == 1)
{
throw handler.TypeMismatch(sourceLocation, eventPayloadType, entrySignature[0]);
}
PLanguageType entrySignatureType = new TupleType(entrySignature.ToArray());
if (!entrySignatureType.IsAssignableFrom(eventPayloadType))
{
throw handler.TypeMismatch(sourceLocation, eventPayloadType, entrySignatureType);
}
}
public static void ValidateMachine(ITranslationErrorHandler handler, Machine machine)
{
State startState = FindStartState(machine, handler);
PLanguageType startStatePayloadType = GetStatePayload(startState, handler);
if (!startStatePayloadType.IsSameTypeAs(machine.PayloadType))
{
throw handler.InternalError(machine.SourceLocation,
"machine payload type is not the same as start state's entry payload type");
}
foreach (Interface machineInterface in machine.Interfaces)
{
if (!machine.PayloadType.IsAssignableFrom(machineInterface.PayloadType))
{
// TODO: add special "invalid machine interface" error
throw handler.TypeMismatch(machine.StartState.Entry?.SourceLocation ?? machine.SourceLocation,
machine.PayloadType,
machineInterface.PayloadType);
}
}
}
private ISet <Variable> ProcessStatement(ISet <Variable> unavailable, IPStmt statement)
{
Contract.Requires(statement != null);
switch (statement)
{
case CompoundStmt compoundStmt:
unavailable = compoundStmt.Statements.Aggregate(unavailable, ProcessStatement);
break;
case AssertStmt assertStmt:
unavailable = ProcessExpr(unavailable, assertStmt.Assertion);
break;
case PrintStmt printStmt:
unavailable = ProcessArgList(printStmt.Args, unavailable, ArgOptions.SwapNotAllowed);
break;
case ReturnStmt returnStmt:
if (returnStmt.ReturnValue != null)
{
unavailable = ProcessExpr(unavailable, returnStmt.ReturnValue);
}
break;
case AssignStmt assignStmt:
unavailable = ProcessExpr(unavailable, assignStmt.Value);
if (assignStmt.Location is VariableAccessExpr assignAccess)
{
unavailable.Remove(assignAccess.Variable);
}
else
{
unavailable = ProcessExpr(unavailable, assignStmt.Location);
}
break;
case MoveAssignStmt moveAssignStmt:
if (moveAssignStmt.FromVariable.Role.Equals(VariableRole.Field))
{
throw handler.MovedField(moveAssignStmt);
}
unavailable.Add(moveAssignStmt.FromVariable);
if (moveAssignStmt.ToLocation is VariableAccessExpr moveAssignAccess)
{
unavailable.Remove(moveAssignAccess.Variable);
}
else
{
unavailable = ProcessExpr(unavailable, moveAssignStmt.ToLocation);
}
break;
case SwapAssignStmt swapAssignStmt:
if (swapAssignStmt.NewLocation is VariableAccessExpr swapAssignAccess)
{
if (unavailable.Contains(swapAssignAccess.Variable))
{
throw handler.SwapAssignUnavailable(swapAssignStmt, swapAssignAccess.Variable);
}
}
else
{
unavailable = ProcessExpr(unavailable, swapAssignStmt.NewLocation);
}
if (unavailable.Contains(swapAssignStmt.OldLocation))
{
throw handler.SwapAssignUnavailable(swapAssignStmt, swapAssignStmt.OldLocation);
}
break;
case InsertStmt insertStmt:
unavailable = ProcessExpr(unavailable, insertStmt.Variable);
unavailable = ProcessExpr(unavailable, insertStmt.Index);
unavailable = ProcessExpr(unavailable, insertStmt.Value);
break;
case RemoveStmt removeStmt:
unavailable = ProcessExpr(unavailable, removeStmt.Variable);
unavailable = ProcessExpr(unavailable, removeStmt.Value);
break;
case WhileStmt whileStmt:
unavailable = ProcessExpr(unavailable, whileStmt.Condition);
// process running the body twice. on the first go, the loop can potentially
// relinquish additional variables on the second go, either the body will use
// one of these variables and throw or reach a fixed point since all paths are
// considered simultaneously. Then, we continue our overapproximation by taking
// the union of no runs and one or more runs.
var bodyUnavailable =
ProcessStatement(new HashSet <Variable>(unavailable), whileStmt.Body);
bodyUnavailable = ProcessExpr(bodyUnavailable, whileStmt.Condition);
// TODO: more efficient way of doing this?
bodyUnavailable = ProcessStatement(bodyUnavailable, whileStmt.Body);
bodyUnavailable = ProcessExpr(bodyUnavailable, whileStmt.Condition);
unavailable.UnionWith(bodyUnavailable);
break;
case IfStmt ifStmt:
unavailable = ProcessExpr(unavailable, ifStmt.Condition);
var thenUnavailable =
ProcessStatement(new HashSet <Variable>(unavailable), ifStmt.ThenBranch);
var elseUnavailable =
ProcessStatement(new HashSet <Variable>(unavailable), ifStmt.ElseBranch);
thenUnavailable.UnionWith(elseUnavailable);
unavailable = thenUnavailable;
break;
case CtorStmt ctorStmt:
unavailable = ProcessArgList(ctorStmt.Arguments, unavailable, ArgOptions.SwapNotAllowed);
break;
case FunCallStmt funCallStmt:
unavailable = ProcessArgList(funCallStmt.ArgsList, unavailable);
funCallStmts.Add(funCallStmt);
break;
case RaiseStmt raiseStmt:
unavailable = ProcessExpr(unavailable, raiseStmt.PEvent);
unavailable = ProcessArgList(raiseStmt.Payload, unavailable, ArgOptions.SwapNotAllowed);
break;
case SendStmt sendStmt:
unavailable = ProcessExpr(unavailable, sendStmt.MachineExpr);
unavailable = ProcessExpr(unavailable, sendStmt.Evt);
unavailable = ProcessArgList(sendStmt.Arguments, unavailable, ArgOptions.SwapNotAllowed);
break;
case AnnounceStmt announceStmt:
unavailable = ProcessExpr(unavailable, announceStmt.PEvent);
if (announceStmt.Payload != null)
{
unavailable = ProcessExpr(unavailable, announceStmt.Payload);
}
break;
case GotoStmt gotoStmt:
if (gotoStmt.Payload != null)
{
unavailable = ProcessExpr(unavailable, gotoStmt.Payload);
}
break;
case ReceiveStmt receiveStmt:
var postUnavailable = new HashSet <Variable>();
var caseVariables = new HashSet <Variable>();
foreach (var recvCase in receiveStmt.Cases)
{
var caseUnavailable =
ProcessStatement(new HashSet <Variable>(unavailable), recvCase.Value.Body);
postUnavailable.UnionWith(caseUnavailable);
caseVariables.UnionWith(recvCase.Value.Signature.Parameters);
}
unavailable = postUnavailable;
unavailable.ExceptWith(caseVariables);
break;
case PopStmt _:
case NoStmt _:
// nothing to check
break;
default:
throw handler.InternalError(statement.SourceLocation,
new ArgumentOutOfRangeException(nameof(statement)));
}
return(unavailable);
}
private static IEnumerable <Interface> InferCreates(IPAST tree, ITranslationErrorHandler handler)
{
switch (tree)
{
case Function function:
if (function.IsForeign)
{
return(function.CreatesInterfaces);
}
return(InferCreates(function.Body, handler));
case AddStmt addStmt:
return(InferCreatesForExpr(addStmt.Variable, handler)
.Union(InferCreatesForExpr(addStmt.Value, handler)));
case AnnounceStmt announce:
return(InferCreatesForExpr(announce.PEvent, handler)
.Union(InferCreatesForExpr(announce.Payload, handler)));
case AssertStmt assertStmt:
return(InferCreatesForExpr(assertStmt.Assertion, handler));
case AssignStmt assignStmt:
return(InferCreatesForExpr(assignStmt.Location, handler)
.Union(InferCreatesForExpr(assignStmt.Value, handler)));
case CompoundStmt compoundStmt:
return(compoundStmt.Statements.SelectMany(tree1 => InferCreates(tree1, handler)));
case CtorStmt ctorStmt:
Interface[] res = new[] { ctorStmt.Interface };
return(res.Union(ctorStmt.Arguments.SelectMany(expr => InferCreatesForExpr(expr, handler))));
case FunCallStmt funCallStmt:
return(InferCreates(funCallStmt.Function, handler)
.Union(funCallStmt.ArgsList.SelectMany(expr => InferCreatesForExpr(expr, handler))));
case GotoStmt gotoStmt:
return(InferCreatesForExpr(gotoStmt.Payload, handler));
case IfStmt ifStmt:
return(InferCreatesForExpr(ifStmt.Condition, handler)
.Union(InferCreates(ifStmt.ThenBranch, handler))
.Union(InferCreates(ifStmt.ElseBranch, handler)));
case InsertStmt insertStmt:
return(InferCreatesForExpr(insertStmt.Variable, handler)
.Union(InferCreatesForExpr(insertStmt.Index, handler))
.Union(InferCreatesForExpr(insertStmt.Value, handler)));
case MoveAssignStmt moveAssignStmt:
return(InferCreatesForExpr(moveAssignStmt.ToLocation, handler));
case NoStmt _:
return(Enumerable.Empty <Interface>());
case PopStmt _:
return(Enumerable.Empty <Interface>());
case PrintStmt printStmt:
return(printStmt.Args.SelectMany(expr => InferCreatesForExpr(expr, handler)));
case RaiseStmt raiseStmt:
return(InferCreatesForExpr(raiseStmt.PEvent, handler)
.Union(raiseStmt.Payload.SelectMany(expr => InferCreatesForExpr(expr, handler))));
case ReceiveStmt receiveStmt:
return(receiveStmt.Cases.SelectMany(x => InferCreates(x.Value, handler)));
case RemoveStmt removeStmt:
return(InferCreatesForExpr(removeStmt.Variable, handler)
.Union(InferCreatesForExpr(removeStmt.Value, handler)));
case ReturnStmt returnStmt:
return(InferCreatesForExpr(returnStmt.ReturnValue, handler));
case StringAssignStmt stringAssignStmt:
return(InferCreatesForExpr(stringAssignStmt.Location, handler)
.Union(stringAssignStmt.Args.SelectMany(expr => InferCreatesForExpr(expr, handler))));
case BreakStmt breakStmt:
return(Enumerable.Empty <Interface>());
case ContinueStmt continueStmt:
return(Enumerable.Empty <Interface>());
case SendStmt sendStmt:
return(InferCreatesForExpr(sendStmt.MachineExpr, handler)
.Union(InferCreatesForExpr(sendStmt.Evt, handler))
.Union(sendStmt.Arguments.SelectMany(expr => InferCreatesForExpr(expr, handler))));
case SwapAssignStmt swapAssignStmt:
return(InferCreatesForExpr(swapAssignStmt.NewLocation, handler));
case WhileStmt whileStmt:
return(InferCreatesForExpr(whileStmt.Condition, handler)
.Union(InferCreates(whileStmt.Body, handler)));
default:
throw handler.InternalError(tree.SourceLocation, new ArgumentOutOfRangeException(nameof(tree)));
}
}