/// <summary>
/// Takes current result and wraps it into try-filter(MethodUnwinder)-finally block that ensures correct "break" behavior for
/// Ruby method calls with a block given in arguments.
///
/// Sets up a RFC frame similarly to MethodDeclaration.
/// </summary>
internal static void ApplyBlockFlowHandlingInternal(MetaObjectBuilder /*!*/ metaBuilder, CallArguments /*!*/ args)
{
// TODO (improvement):
// We don't special case null block here, although we could (we would need a test for that then).
// We could also statically know (via call-site flag) that the current method is not a proc-converter (passed by ref),
// which would make such calls faster.
if (metaBuilder.Error || !args.Signature.HasBlock)
{
return;
}
Expression rfcVariable = metaBuilder.GetTemporary(typeof(RuntimeFlowControl), "#rfc");
ParameterExpression methodUnwinder = metaBuilder.GetTemporary(typeof(MethodUnwinder), "#unwinder");
Expression resultVariable = metaBuilder.GetTemporary(typeof(object), "#result");
metaBuilder.Result = Ast.Block(
// initialize frame (RFC):
Ast.Assign(rfcVariable, Methods.CreateRfcForMethod.OpCall(AstUtils.Convert(args.GetBlockExpression(), typeof(Proc)))),
AstUtils.Try(
Ast.Assign(resultVariable, metaBuilder.Result)
).Filter(methodUnwinder, Ast.Equal(Ast.Field(methodUnwinder, MethodUnwinder.TargetFrameField), rfcVariable),
// return unwinder.ReturnValue;
Ast.Assign(resultVariable, Ast.Field(methodUnwinder, MethodUnwinder.ReturnValueField))
).Finally(
// we need to mark the RFC dead snce the block might escape and break later:
Ast.Assign(Ast.Field(rfcVariable, RuntimeFlowControl.IsActiveMethodField), Ast.Constant(false))
),
resultVariable
);
}
private MSAst.Expression AddModulePublishing(MSAst.Expression body)
{
if (IsModule)
{
PythonCompilerOptions pco = _compilerContext.Options as PythonCompilerOptions;
string moduleName = ModuleName;
if ((pco.Module & ModuleOptions.Initialize) != 0)
{
var tmp = Ast.Variable(typeof(object), "$originalModule");
// TODO: Should be try/fault
body = Ast.Block(
new[] { tmp },
AstUtils.Try(
Ast.Assign(tmp, Ast.Call(AstMethods.PublishModule, LocalContext, Ast.Constant(moduleName))),
body
).Catch(
typeof(Exception),
Ast.Call(AstMethods.RemoveModule, LocalContext, Ast.Constant(moduleName), tmp),
Ast.Rethrow(body.Type)
)
);
}
}
return(body);
}
/// <summary>
/// Takes current result and wraps it into try-filter(MethodUnwinder)-finally block that ensures correct "break" behavior for
/// library method calls with block given in bfcVariable (BlockParam).
/// </summary>
internal static void ApplyBlockFlowHandlingInternal(MetaObjectBuilder /*!*/ metaBuilder, CallArguments /*!*/ args)
{
if (metaBuilder.Error)
{
return;
}
Expression expression = metaBuilder.Result;
Expression bfcVariable = metaBuilder.BfcVariable;
// Method call with proc can invoke control flow that returns an arbitrary value from the call, so we need to type result to Object.
// Otherwise, the result could only be result of targetExpression unless its return type is void.
Type resultType = (bfcVariable != null) ? typeof(object) : expression.Type;
Expression resultVariable;
if (resultType != typeof(void))
{
resultVariable = metaBuilder.GetTemporary(resultType, "#result");
}
else
{
resultVariable = Expression.Empty();
}
if (expression.Type != typeof(void))
{
expression = Ast.Assign(resultVariable, AstUtils.Convert(expression, resultType));
}
// a non-null proc is being passed to the callee:
if (bfcVariable != null)
{
ParameterExpression methodUnwinder = metaBuilder.GetTemporary(typeof(MethodUnwinder), "#unwinder");
expression = AstFactory.Block(
Ast.Assign(bfcVariable, Methods.CreateBfcForLibraryMethod.OpCall(AstUtils.Convert(args.GetBlockExpression(), typeof(Proc)))),
AstUtils.Try(
expression
).Filter(methodUnwinder, Methods.IsProcConverterTarget.OpCall(bfcVariable, methodUnwinder),
Ast.Assign(resultVariable, Ast.Field(methodUnwinder, MethodUnwinder.ReturnValueField))
).Finally(
Methods.LeaveProcConverter.OpCall(bfcVariable)
),
resultVariable
);
}
metaBuilder.Result = expression;
}
/// <summary>
/// Helper to wrap explicit conversion call into try/catch incase it throws an exception. If
/// it throws the default value is returned.
/// </summary>
private static Expression WrapForThrowingTry(ConversionResultKind kind, bool isImplicit, Expression ret, Type retType)
{
if (!isImplicit && kind == ConversionResultKind.ExplicitTry)
{
Expression convFailed = GetTryConvertReturnValue(retType);
ParameterExpression tmp = Expression.Variable(convFailed.Type == typeof(object) ? typeof(object) : ret.Type, "tmp");
ret = Expression.Block(
new ParameterExpression[] { tmp },
AstUtils.Try(
Expression.Assign(tmp, AstUtils.Convert(ret, tmp.Type))
).Catch(
typeof(Exception),
Expression.Assign(tmp, convFailed)
),
tmp
);
}
return(ret);
}
internal static MSA.Expression /*!*/ MakeCallWithBlockRetryable(AstGenerator /*!*/ gen, MSA.Expression /*!*/ invoke,
MSA.Expression blockArgVariable, MSA.Expression transformedBlock, bool isBlockDefinition)
{
Assert.NotNull(invoke);
Debug.Assert((blockArgVariable == null) == (transformedBlock == null));
// see Ruby Language.doc/Control Flow Implementation/Method Call With a Block
MSA.Expression resultVariable = gen.CurrentScope.DefineHiddenVariable("#method-result", typeof(object));
MSA.ParameterExpression evalUnwinder = gen.CurrentScope.DefineHiddenVariable("#unwinder", typeof(EvalUnwinder));
MSA.LabelTarget label = Ast.Label();
return(AstFactory.Block(
Ast.Assign(blockArgVariable, Ast.Convert(transformedBlock, blockArgVariable.Type)),
AstFactory.Infinite(label, null,
(!isBlockDefinition) ?
(MSA.Expression)Ast.Empty() :
(MSA.Expression)Methods.InitializeBlock.OpCall(blockArgVariable),
AstUtils.Try(
Ast.Assign(resultVariable, invoke)
).Catch(evalUnwinder,
Ast.Assign(
resultVariable,
Ast.Field(evalUnwinder, EvalUnwinder.ReturnValueField)
)
),
// if result != RetrySingleton then break end
AstUtils.Unless(Methods.IsRetrySingleton.OpCall(AstFactory.Box(resultVariable)), Ast.Break(label)),
// if blockParam == #block then retry end
(gen.CurrentMethod.IsTopLevelCode) ? Ast.Empty() :
AstUtils.IfThen(Ast.Equal(gen.MakeMethodBlockParameterRead(), blockArgVariable), RetryStatement.TransformRetry(gen))
),
resultVariable
));
}
/// <summary>
/// WithStatement is translated to the DLR AST equivalent to
/// the following Python code snippet (from with statement spec):
///
/// mgr = (EXPR)
/// exit = mgr.__exit__ # Not calling it yet
/// value = mgr.__enter__()
/// exc = True
/// try:
/// VAR = value # Only if "as VAR" is present
/// BLOCK
/// except:
/// # The exceptional case is handled here
/// exc = False
/// if not exit(*sys.exc_info()):
/// raise
/// # The exception is swallowed if exit() returns true
/// finally:
/// # The normal and non-local-goto cases are handled here
/// if exc:
/// exit(None, None, None)
///
/// </summary>
public override MSAst.Expression Reduce()
{
// Five statements in the result...
ReadOnlyCollectionBuilder <MSAst.Expression> statements = new ReadOnlyCollectionBuilder <MSAst.Expression>(6);
ReadOnlyCollectionBuilder <MSAst.ParameterExpression> variables = new ReadOnlyCollectionBuilder <MSAst.ParameterExpression>(6);
MSAst.ParameterExpression lineUpdated = Ast.Variable(typeof(bool), "$lineUpdated_with");
variables.Add(lineUpdated);
//******************************************************************
// 1. mgr = (EXPR)
//******************************************************************
MSAst.ParameterExpression manager = Ast.Variable(typeof(object), "with_manager");
variables.Add(manager);
statements.Add(
GlobalParent.AddDebugInfo(
Ast.Assign(
manager,
_contextManager
),
new SourceSpan(GlobalParent.IndexToLocation(StartIndex), GlobalParent.IndexToLocation(_headerIndex))
)
);
//******************************************************************
// 2. exit = mgr.__exit__ # Not calling it yet
//******************************************************************
MSAst.ParameterExpression exit = Ast.Variable(typeof(object), "with_exit");
variables.Add(exit);
statements.Add(
MakeAssignment(
exit,
GlobalParent.Get(
"__exit__",
manager
)
)
);
//******************************************************************
// 3. value = mgr.__enter__()
//******************************************************************
MSAst.ParameterExpression value = Ast.Variable(typeof(object), "with_value");
variables.Add(value);
statements.Add(
GlobalParent.AddDebugInfoAndVoid(
MakeAssignment(
value,
Parent.Invoke(
new CallSignature(0),
Parent.LocalContext,
GlobalParent.Get(
"__enter__",
manager
)
)
),
new SourceSpan(GlobalParent.IndexToLocation(StartIndex), GlobalParent.IndexToLocation(_headerIndex))
)
);
//******************************************************************
// 4. exc = True
//******************************************************************
MSAst.ParameterExpression exc = Ast.Variable(typeof(bool), "with_exc");
variables.Add(exc);
statements.Add(
MakeAssignment(
exc,
AstUtils.Constant(true)
)
);
//******************************************************************
// 5. The final try statement:
//
// try:
// VAR = value # Only if "as VAR" is present
// BLOCK
// except:
// # The exceptional case is handled here
// exc = False
// if not exit(*sys.exc_info()):
// raise
// # The exception is swallowed if exit() returns true
// finally:
// # The normal and non-local-goto cases are handled here
// if exc:
// exit(None, None, None)
//******************************************************************
var previousException = Ast.Variable(typeof(Exception), "$previousException");
variables.Add(previousException);
MSAst.ParameterExpression exception;
statements.Add(
// try:
AstUtils.Try(
AstUtils.Try(// try statement body
PushLineUpdated(false, lineUpdated),
Ast.Assign(previousException, Ast.Call(AstMethods.SaveCurrentException)),
_var != null ?
(MSAst.Expression)Ast.Block(
// VAR = value
_var.TransformSet(SourceSpan.None, value, PythonOperationKind.None),
// BLOCK
_body,
AstUtils.Empty()
) :
// BLOCK
(MSAst.Expression)_body // except:, // try statement location
).Catch(exception = Ast.Variable(typeof(Exception), "exception"),
// Python specific exception handling code
TryStatement.GetTracebackHeader(
this,
exception,
GlobalParent.AddDebugInfoAndVoid(
Ast.Block(
Ast.Call(AstMethods.SetCurrentException, Parent.LocalContext, exception),
// exc = False
MakeAssignment(
exc,
AstUtils.Constant(false)
),
// if not exit(*sys.exc_info()):
// raise
AstUtils.IfThen(
GlobalParent.Convert(
typeof(bool),
ConversionResultKind.ExplicitCast,
GlobalParent.Operation(
typeof(bool),
PythonOperationKind.IsFalse,
MakeExitCall(exit, exception)
)
),
UpdateLineUpdated(true),
Ast.Throw(
Ast.Call(
AstMethods.MakeRethrowExceptionWorker,
exception
)
)
)
),
_body.Span
)
),
PopLineUpdated(lineUpdated),
Ast.Empty()
)
// finally:
).Finally(
Ast.Call(AstMethods.RestoreCurrentException, previousException),
// if exc:
// exit(None, None, None)
AstUtils.IfThen(
exc,
GlobalParent.AddDebugInfoAndVoid(
Ast.Block(
MSAst.DynamicExpression.Dynamic(
GlobalParent.PyContext.Invoke(
new CallSignature(3) // signature doesn't include function
),
typeof(object),
new MSAst.Expression[] {
Parent.LocalContext,
exit,
AstUtils.Constant(null),
AstUtils.Constant(null),
AstUtils.Constant(null)
}
),
Ast.Empty()
),
_contextManager.Span
)
)
)
);
statements.Add(AstUtils.Empty());
return(Ast.Block(variables.ToReadOnlyCollection(), statements.ToReadOnlyCollection()));
}
/// <summary>
/// Creates the LambdaExpression which implements the body of the function.
///
/// The functions signature is either "object Function(PythonFunction, ...)"
/// where there is one object parameter for each user defined parameter or
/// object Function(PythonFunction, object[]) for functions which take more
/// than PythonCallTargets.MaxArgs arguments.
/// </summary>
private LightLambdaExpression CreateFunctionLambda()
{
bool needsWrapperMethod = _parameters.Length > PythonCallTargets.MaxArgs;
Type delegateType = GetDelegateType(_parameters, needsWrapperMethod, out _);
MSAst.ParameterExpression localContext = null;
ReadOnlyCollectionBuilder <MSAst.ParameterExpression> locals = new ReadOnlyCollectionBuilder <MSAst.ParameterExpression>();
if (NeedsLocalContext)
{
localContext = LocalCodeContextVariable;
locals.Add(localContext);
}
MSAst.ParameterExpression[] parameters = CreateParameters(needsWrapperMethod, locals);
List <MSAst.Expression> init = new List <MSAst.Expression>();
foreach (var param in _parameters)
{
if (GetVariableExpression(param.PythonVariable) is IPythonVariableExpression pyVar)
{
var varInit = pyVar.Create();
if (varInit != null)
{
init.Add(varInit);
}
}
}
// Transform the parameters.
init.Add(Ast.ClearDebugInfo(GlobalParent.Document));
locals.Add(PythonAst._globalContext);
init.Add(Ast.Assign(PythonAst._globalContext, new GetGlobalContextExpression(_parentContext)));
GlobalParent.PrepareScope(locals, init);
// Create variables and references. Since references refer to
// parameters, do this after parameters have been created.
CreateFunctionVariables(locals, init);
// If the __class__ variable is used in a class method then we need to initialize it.
// This must be done before parameter initialization (in case one of the parameters is called __class__).
ClassDefinition parent = FindParentOfType <ClassDefinition>();
if (parent != null && TryGetVariable("__class__", out PythonVariable pVar))
{
init.Add(
AssignValue(
GetVariableExpression(pVar),
Ast.Call(AstMethods.LookupName, parent.Parent.LocalContext, Ast.Constant(parent.Name))
)
);
}
// Initialize parameters - unpack tuples.
// Since tuples unpack into locals, this must be done after locals have been created.
InitializeParameters(init, needsWrapperMethod, parameters);
List <MSAst.Expression> statements = new List <MSAst.Expression>();
// add beginning sequence point
var start = GlobalParent.IndexToLocation(StartIndex);
statements.Add(GlobalParent.AddDebugInfo(
AstUtils.Empty(),
new SourceSpan(new SourceLocation(0, start.Line, start.Column), new SourceLocation(0, start.Line, int.MaxValue))));
// For generators, we need to do a check before the first statement for Generator.Throw() / Generator.Close().
// The exception traceback needs to come from the generator's method body, and so we must do the check and throw
// from inside the generator.
if (IsGenerator)
{
MSAst.Expression s1 = YieldExpression.CreateCheckThrowExpression(SourceSpan.None);
statements.Add(s1);
}
MSAst.ParameterExpression extracted = null;
if (!IsGenerator && CanSetSysExcInfo)
{
// need to allocate the exception here so we don't share w/ exceptions made & freed
// during the body.
extracted = Ast.Parameter(typeof(Exception), "$ex");
locals.Add(extracted);
}
if (Body.CanThrow && !(Body is SuiteStatement) && Body.StartIndex != -1)
{
statements.Add(UpdateLineNumber(GlobalParent.IndexToLocation(Body.StartIndex).Line));
}
statements.Add(Body);
MSAst.Expression body = Ast.Block(statements);
// If this function can modify sys.exc_info() (_canSetSysExcInfo), then it must restore the result on finish.
//
// Wrap in
// $temp = PythonOps.SaveCurrentException()
// <body>
// PythonOps.RestoreCurrentException($temp)
// Skip this if we're a generator. For generators, the try finally is handled by the PythonGenerator class
// before it's invoked. This is because the restoration must occur at every place the function returns from
// a yield point. That's different than the finally semantics in a generator.
if (extracted != null)
{
MSAst.Expression s = AstUtils.Try(
Ast.Assign(
extracted,
Ast.Call(AstMethods.SaveCurrentException)
),
body
).Finally(
Ast.Call(
AstMethods.RestoreCurrentException, extracted
)
);
body = s;
}
if (Body.CanThrow && GlobalParent.PyContext.PythonOptions.Frames)
{
body = AddFrame(LocalContext, Ast.Property(_functionParam, typeof(PythonFunction).GetProperty("__code__")), body);
locals.Add(FunctionStackVariable);
}
body = AddProfiling(body);
body = WrapScopeStatements(body, Body.CanThrow);
body = Ast.Block(body, AstUtils.Empty());
body = AddReturnTarget(body);
MSAst.Expression bodyStmt = body;
if (localContext != null)
{
var createLocal = CreateLocalContext(_parentContext);
init.Add(
Ast.Assign(
localContext,
createLocal
)
);
}
init.Add(bodyStmt);
bodyStmt = Ast.Block(init);
// wrap a scope if needed
bodyStmt = Ast.Block(locals.ToReadOnlyCollection(), bodyStmt);
return(AstUtils.LightLambda(
typeof(object),
delegateType,
AddDefaultReturn(bodyStmt, typeof(object)),
Name + "$" + Interlocked.Increment(ref _lambdaId),
parameters
));
}
internal override MSA.Expression /*!*/ Transform(AstGenerator /*!*/ gen)
{
MSA.Expression parentScope = gen.CurrentScopeVariable;
ScopeBuilder scope = new ScopeBuilder();
// define hidden parameters and RHS-placeholders (#1..#n will be used as RHS of a parallel assignment):
MSA.Expression blockParameter, selfParameter;
MSA.ParameterExpression[] parameters = DefineParameters(out selfParameter, out blockParameter);
MSA.Expression scopeVariable = scope.DefineHiddenVariable("#scope", typeof(RubyBlockScope));
MSA.LabelTarget redoLabel = Ast.Label();
gen.EnterBlockDefinition(
scope,
blockParameter,
selfParameter,
scopeVariable,
redoLabel
);
if (_definedScope != null)
{
_definedScope.TransformLocals(scope);
}
MSA.Expression paramInit = MakeParametersInitialization(gen, parameters);
MSA.ParameterExpression blockUnwinder = scope.DefineHiddenVariable("#unwinder", typeof(BlockUnwinder));
MSA.Expression loop = AstFactory.Infinite(null, redoLabel,
AstUtils.Try(
gen.TransformStatements(_body, ResultOperation.Return)
).Catch(blockUnwinder,
// redo:
AstUtils.IfThen(Ast.Field(blockUnwinder, BlockUnwinder.IsRedoField), Ast.Continue(redoLabel)),
// next:
gen.Return(Ast.Field(blockUnwinder, BlockUnwinder.ReturnValueField))
)
);
if (gen.TraceEnabled)
{
int firstStatementLine = _body.Count > 0 ? _body[0].Location.Start.Line : Location.End.Line;
int lastStatementLine = _body.Count > 0 ? _body[_body.Count - 1].Location.End.Line : Location.End.Line;
loop = Ast.TryFinally(
Ast.Block(
Methods.TraceBlockCall.OpCall(scopeVariable, blockParameter, Ast.Convert(Ast.Constant(gen.SourceUnit.Path), typeof(string)), Ast.Constant(firstStatementLine)),
loop
),
Methods.TraceBlockReturn.OpCall(scopeVariable, blockParameter, Ast.Convert(Ast.Constant(gen.SourceUnit.Path), typeof(string)), Ast.Constant(lastStatementLine))
);
}
MSA.Expression body = Ast.Block(
Ast.Assign(scopeVariable,
Methods.CreateBlockScope.OpCall(scope.VisibleVariables(), parentScope, blockParameter, selfParameter)
),
paramInit,
loop,
Ast.Empty()
);
body = gen.AddReturnTarget(scope.CreateScope(body));
gen.LeaveBlockDefinition();
int parameterCount = _parameters.LeftValues.Count;
var attributes = _parameters.GetBlockSignatureAttributes();
return(Methods.DefineBlock.OpCall(
gen.CurrentScopeVariable,
gen.CurrentRfcVariable,
gen.CurrentSelfVariable,
Ast.Lambda(
BlockDispatcher.GetDelegateType(parameterCount, attributes),
body,
gen.EncodeMethodName(gen.CurrentMethod.MethodName, Location),
new ReadOnlyCollection <MSA.ParameterExpression>(parameters)
),
Ast.Constant(parameterCount),
Ast.Constant(attributes)
));
}
// see Ruby Language.doc/Runtime/Control Flow Implementation/While-Until
internal override MSA.Expression /*!*/ TransformRead(AstGenerator /*!*/ gen)
{
MSA.Expression resultVariable = gen.CurrentScope.DefineHiddenVariable("#loop-result", typeof(object));
MSA.Expression redoVariable = gen.CurrentScope.DefineHiddenVariable("#skip-condition", typeof(bool));
MSA.ParameterExpression blockUnwinder = gen.CurrentScope.DefineHiddenVariable("#unwinder", typeof(BlockUnwinder));
MSA.ParameterExpression evalUnwinder = gen.CurrentScope.DefineHiddenVariable("#unwinder", typeof(EvalUnwinder));
bool isInnerLoop = gen.CurrentLoop != null;
MSA.LabelTarget breakLabel = Ast.Label();
MSA.LabelTarget continueLabel = Ast.Label();
gen.EnterLoop(redoVariable, resultVariable, breakLabel, continueLabel);
MSA.Expression transformedBody = gen.TransformStatements(_statements, ResultOperation.Ignore);
MSA.Expression transformedCondition = AstFactory.IsTrue(_condition.TransformRead(gen));
gen.LeaveLoop();
MSA.Expression conditionPositiveStmt, conditionNegativeStmt;
if (_isWhileLoop)
{
conditionPositiveStmt = Ast.Empty();
conditionNegativeStmt = Ast.Break(breakLabel);
}
else
{
conditionPositiveStmt = Ast.Break(breakLabel);
conditionNegativeStmt = Ast.Empty();
}
// make the loop first:
MSA.Expression loop = Ast.Block(
Ast.Assign(redoVariable, Ast.Constant(_isPostTest)),
AstFactory.Infinite(breakLabel, continueLabel,
AstUtils.Try(
AstUtils.If(redoVariable,
Ast.Assign(redoVariable, Ast.Constant(false))
).ElseIf(transformedCondition,
conditionPositiveStmt
).Else(
conditionNegativeStmt
),
transformedBody
).Catch(blockUnwinder,
// redo = u.IsRedo
Ast.Assign(redoVariable, Ast.Field(blockUnwinder, BlockUnwinder.IsRedoField))
).Filter(evalUnwinder, Ast.Equal(Ast.Field(evalUnwinder, EvalUnwinder.ReasonField), AstFactory.BlockReturnReasonBreak),
// result = unwinder.ReturnValue
Ast.Assign(resultVariable, Ast.Field(evalUnwinder, EvalUnwinder.ReturnValueField)),
Ast.Break(breakLabel)
)
),
Ast.Empty()
);
// wrap it to try finally that updates RFC state:
if (!isInnerLoop)
{
loop = AstUtils.Try(
Ast.Assign(Ast.Field(gen.CurrentRfcVariable, RuntimeFlowControl.InLoopField), Ast.Constant(true)),
loop
).Finally(
Ast.Assign(Ast.Field(gen.CurrentRfcVariable, RuntimeFlowControl.InLoopField), Ast.Constant(false))
);
}
return(AstFactory.Block(loop, resultVariable));
}
