public override MSAst.Expression Reduce()
{
if (_statements.Length == 0)
{
return(GlobalParent.AddDebugInfoAndVoid(AstUtils.Empty(), Span));
}
ReadOnlyCollectionBuilder <MSAst.Expression> statements = new ReadOnlyCollectionBuilder <MSAst.Expression>();
int curStart = -1;
foreach (var statement in _statements)
{
// CPython debugging treats multiple statements on the same line as a single step, we
// match that behavior here.
int newline = GlobalParent.IndexToLocation(statement.StartIndex).Line;
if (newline == curStart)
{
statements.Add(new DebugInfoRemovalExpression(statement, curStart));
}
else
{
if (statement.CanThrow && newline != -1)
{
statements.Add(UpdateLineNumber(newline));
}
statements.Add(statement);
}
curStart = newline;
}
return(Ast.Block(statements.ToReadOnlyCollection()));
}
public override MSAst.Expression Reduce()
{
Debug.Assert(PythonVariable != null, "Shouldn't be called by lambda expression");
MSAst.Expression function = MakeFunctionExpression();
return(GlobalParent.AddDebugInfoAndVoid(
AssignValue(Parent.GetVariableExpression(PythonVariable), function),
new SourceSpan(GlobalParent.IndexToLocation(StartIndex), GlobalParent.IndexToLocation(HeaderIndex))
));
}
private MSAst.Expression ReduceWorker(bool optimizeDynamicConvert)
{
// Only the body is "in the loop" for the purposes of break/continue
// The "else" clause is outside
ConstantExpression constTest = _test as ConstantExpression;
if (constTest != null && constTest.Value is int)
{
// while 0: / while 1:
int val = (int)constTest.Value;
if (val == 0)
{
// completely optimize the loop away
if (_else == null)
{
return(MSAst.Expression.Empty());
}
else
{
return(_else);
}
}
MSAst.Expression test = MSAst.Expression.Constant(true);
MSAst.Expression res = AstUtils.While(
test,
_body,
_else,
_break,
_continue
);
if (GlobalParent.IndexToLocation(_test.StartIndex).Line != GlobalParent.IndexToLocation(_body.StartIndex).Line)
{
res = GlobalParent.AddDebugInfoAndVoid(res, _test.Span);
}
return(res);
}
return(AstUtils.While(
GlobalParent.AddDebugInfo(
optimizeDynamicConvert ?
TransformAndDynamicConvert(_test, typeof(bool)) :
GlobalParent.Convert(typeof(bool), Microsoft.Scripting.Actions.ConversionResultKind.ExplicitCast, _test),
Header
),
_body,
_else,
_break,
_continue
));
}
public override MSAst.Expression Reduce()
{
var codeObj = GetOrMakeFunctionCode();
var funcCode = GlobalParent.Constant(codeObj);
FuncCodeExpr = funcCode;
MSAst.Expression lambda;
if (EmitDebugSymbols)
{
lambda = GetLambda();
}
else
{
lambda = NullLambda;
ThreadPool.QueueUserWorkItem((x) => {
// class defs are almost always run, so start
// compiling the code now so it might be ready
// when we actually go and execute it
codeObj.UpdateDelegate(PyContext, true);
});
}
MSAst.Expression classDef = Ast.Call(
AstMethods.MakeClass,
funcCode,
lambda,
Parent.LocalContext,
AstUtils.Constant(_name),
Ast.NewArrayInit(
typeof(object),
ToObjectArray(_bases)
),
Metaclass is null ? AstUtils.Constant(null, typeof(object)) : AstUtils.Convert(Metaclass, typeof(object)),
AstUtils.Constant(FindSelfNames())
);
classDef = AddDecorators(classDef, Decorators);
return(GlobalParent.AddDebugInfoAndVoid(
AssignValue(Parent.GetVariableExpression(PythonVariable), classDef),
new SourceSpan(
GlobalParent.IndexToLocation(StartIndex),
GlobalParent.IndexToLocation(HeaderIndex)
)
));
}
/// <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);
// 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);
}
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 (Body.CanThrow && GlobalParent.PyContext.PythonOptions.Frames)
{
body = AddFrame(LocalContext, Ast.Property(_functionParam, typeof(PythonFunction).GetProperty(nameof(PythonFunction.__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 + "$" + Interlocked.Increment(ref _lambdaId),
parameters
));
}
/// <summary>
/// WithStatement is translated to the DLR AST equivalent to
/// the following Python code snippet (from with statement spec):
///
/// mgr = (EXPR)
/// exit = mgr.__exit__ # Not calling it yet
/// value = mgr.__enter__()
/// exc = True
/// try:
/// VAR = value # Only if "as VAR" is present
/// BLOCK
/// except:
/// # The exceptional case is handled here
/// exc = False
/// if not exit(*sys.exc_info()):
/// raise
/// # The exception is swallowed if exit() returns true
/// finally:
/// # The normal and non-local-goto cases are handled here
/// if exc:
/// exit(None, None, None)
///
/// </summary>
public override MSAst.Expression Reduce()
{
// Five statements in the result...
ReadOnlyCollectionBuilder <MSAst.Expression> statements = new ReadOnlyCollectionBuilder <MSAst.Expression>(6);
ReadOnlyCollectionBuilder <MSAst.ParameterExpression> variables = new ReadOnlyCollectionBuilder <MSAst.ParameterExpression>(6);
MSAst.ParameterExpression lineUpdated = Ast.Variable(typeof(bool), "$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;
Delegate originalDelegate;
Type delegateType = GetDelegateType(_parameters, needsWrapperMethod, out originalDelegate);
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)
{
IPythonVariableExpression pyVar = GetVariableExpression(param.PythonVariable) as IPythonVariableExpression;
if (pyVar != null)
{
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 the 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>();
PythonVariable pVar;
if (parent != null && TryGetVariable("__class__", out 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, Int32.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 + "$" + Interlocked.Increment(ref _lambdaId),
parameters
));
}
public override MSAst.Expression Reduce()
{
// allocated all variables here so they won't be shared w/ other
// locals allocated during the body or except blocks.
MSAst.ParameterExpression?lineUpdated = null;
MSAst.ParameterExpression?runElse = null;
MSAst.ParameterExpression?previousExceptionContext = null;
if (Else != null || _handlers.Length > 0)
{
lineUpdated = Ast.Variable(typeof(bool), "$lineUpdated_try");
if (Else != null)
{
runElse = Ast.Variable(typeof(bool), "run_else");
}
}
// don't allocate locals below here...
MSAst.Expression body = Body;
MSAst.Expression? @else = Else;
MSAst.Expression? @catch;
MSAst.Expression result;
MSAst.ParameterExpression?exception;
if (_handlers.Length > 0)
{
previousExceptionContext = Ast.Variable(typeof(Exception), "$previousException");
exception = Ast.Variable(typeof(Exception), "$exception");
@catch = TransformHandlers(exception, previousExceptionContext);
}
else if (Finally != null)
{
exception = Ast.Variable(typeof(Exception), "$exception");
@catch = null;
}
else
{
exception = null;
@catch = null;
}
// We have else clause, must generate guard around it
if (@else != null)
{
Debug.Assert(@catch != null);
// run_else = true;
// try {
// try_body
// } catch ( ... ) {
// run_else = false;
// catch_body
// }
// if (run_else) {
// else_body
// }
result =
Ast.Block(
Ast.Assign(runElse, AstUtils.Constant(true)),
// save existing line updated, we could choose to do this only for nested exception handlers.
PushLineUpdated(false, lineUpdated),
LightExceptions.RewriteExternal(
AstUtils.Try(
Parent.AddDebugInfo(AstUtils.Empty(), new SourceSpan(Span.Start, GlobalParent.IndexToLocation(HeaderIndex))),
Ast.Assign(previousExceptionContext, Ast.Call(AstMethods.SaveCurrentException)),
body,
AstUtils.Constant(null)
).Catch(exception,
Ast.Assign(runElse, AstUtils.Constant(false)),
@catch,
// restore existing line updated after exception handler completes
PopLineUpdated(lineUpdated),
Ast.Assign(exception, Ast.Constant(null, typeof(Exception))),
AstUtils.Constant(null)
)
),
AstUtils.IfThen(runElse,
@else
),
AstUtils.Empty()
);
}
else if (@catch != null) // no "else" clause
// try {
// <try body>
// } catch (Exception e) {
// ... catch handling ...
// }
//
{
result =
LightExceptions.RewriteExternal(
AstUtils.Try(
GlobalParent.AddDebugInfo(AstUtils.Empty(), new SourceSpan(Span.Start, GlobalParent.IndexToLocation(HeaderIndex))),
// save existing line updated
PushLineUpdated(false, lineUpdated),
Ast.Assign(previousExceptionContext, Ast.Call(AstMethods.SaveCurrentException)),
body,
AstUtils.Constant(null)
).Catch(exception,
@catch,
// restore existing line updated after exception handler completes
PopLineUpdated(lineUpdated),
Ast.Assign(exception, Ast.Constant(null, typeof(Exception))),
AstUtils.Constant(null)
)
);
}
else
{
result = body;
}
return(Ast.Block(
GetVariables(lineUpdated, runElse, previousExceptionContext),
AddFinally(result),
AstUtils.Default(typeof(void))
));
}
private MSAst.Expression TransformHandlers(MSAst.ParameterExpression exception, MSAst.ParameterExpression previousException)
{
Assert.NotEmpty(_handlers);
MSAst.ParameterExpression extracted = Ast.Variable(typeof(object), "$extracted");
var tests = new List <Microsoft.Scripting.Ast.IfStatementTest>(_handlers.Length);
MSAst.ParameterExpression?converted = null;
MSAst.Expression? catchAll = null;
for (int index = 0; index < _handlers.Length; index++)
{
TryStatementHandler tsh = _handlers[index];
if (tsh.Test != null)
{
Microsoft.Scripting.Ast.IfStatementTest ist;
// translating:
// except Test ...
//
// generate following AST for the Test (common part):
// CheckException(exception, Test)
MSAst.Expression test =
Ast.Call(
AstMethods.CheckException,
Parent.LocalContext,
extracted,
AstUtils.Convert(tsh.Test, typeof(object))
);
if (tsh.Target != null)
{
// translating:
// except Test as Target:
// <body>
// into:
// if ((converted = CheckException(exception, Test)) != null) {
// try {
// Target = converted;
// traceback-header
// <body>
// }
// finally {
// del Target
// }
// }
if (converted == null)
{
converted = Ast.Variable(typeof(object), "$converted");
}
ist = AstUtils.IfCondition(
Ast.NotEqual(
Ast.Assign(converted, test),
AstUtils.Constant(null)
),
Ast.TryFinally(
Ast.Block(
tsh.Target.TransformSet(SourceSpan.None, converted, PythonOperationKind.None),
GlobalParent.AddDebugInfo(
GetTracebackHeader(this, exception, tsh.Body),
new SourceSpan(GlobalParent.IndexToLocation(tsh.StartIndex), GlobalParent.IndexToLocation(tsh.HeaderIndex))
),
AstUtils.Empty()
),
Ast.Block(
Ast.Call(AstMethods.RestoreCurrentException, previousException),
tsh.Target.TransformSet(SourceSpan.None, AstUtils.Constant(null), PythonOperationKind.None),
tsh.Target.TransformDelete()
)
)
);
}
else
{
// translating:
// except Test:
// <body>
// into:
// if (CheckException(exception, Test) != null) {
// traceback-header
// <body>
// }
ist = AstUtils.IfCondition(
Ast.NotEqual(
test,
AstUtils.Constant(null)
),
Ast.TryFinally(
GlobalParent.AddDebugInfo(
GetTracebackHeader(this, exception, tsh.Body),
new SourceSpan(GlobalParent.IndexToLocation(tsh.StartIndex), GlobalParent.IndexToLocation(tsh.HeaderIndex))
),
Ast.Call(AstMethods.RestoreCurrentException, previousException)
)
);
}
// Add the test to the if statement test cascade
tests.Add(ist);
}
else
{
Debug.Assert(index == _handlers.Length - 1);
Debug.Assert(catchAll == null);
// translating:
// except:
// <body>
// into:
// {
// traceback-header
// <body>
// }
catchAll =
Ast.TryFinally(
GlobalParent.AddDebugInfo(
GetTracebackHeader(this, exception, tsh.Body),
new SourceSpan(GlobalParent.IndexToLocation(tsh.StartIndex), GlobalParent.IndexToLocation(tsh.HeaderIndex))
),
Ast.Call(AstMethods.RestoreCurrentException, previousException)
);
}
}
MSAst.Expression body;
if (tests.Count > 0)
{
// rethrow the exception if we have no catch-all block
if (catchAll == null)
{
catchAll = Ast.Block(
Parent.GetSaveLineNumberExpression(exception, true),
Ast.Throw(
Ast.Call(
typeof(ExceptionHelpers).GetMethod(nameof(ExceptionHelpers.UpdateForRethrow)),
exception
)
)
);
}
body = AstUtils.If(
tests.ToArray(),
catchAll
);
}
else
{
Debug.Assert(catchAll != null);
body = catchAll !;
}
IList <MSAst.ParameterExpression> args;
if (converted != null)
{
args = new ReadOnlyCollectionBuilder <MSAst.ParameterExpression> {
converted, extracted
};
}
else
{
args = new ReadOnlyCollectionBuilder <MSAst.ParameterExpression> {
extracted
};
}
// Codegen becomes:
// extracted = PythonOps.SetCurrentException(exception)
// try:
// < dynamic exception analysis >
// extracted = None
return(Ast.Block(
args,
Ast.Assign(
extracted,
Ast.Call(AstMethods.SetCurrentException, Parent.LocalContext, exception)
),
body,
Ast.Assign(extracted, Ast.Constant(null)),
AstUtils.Empty()
));
}
private MSAst.Expression AddFinally(MSAst.Expression /*!*/ body)
{
if (Finally != null)
{
MSAst.ParameterExpression tryThrows = Ast.Variable(typeof(Exception), "$tryThrows");
MSAst.ParameterExpression locException = Ast.Variable(typeof(Exception), "$localException");
MSAst.Expression? @finally = Finally;
// lots is going on here. We need to consider:
// 1. Exceptions propagating out of try/except/finally. Here we need to save the line #
// from the exception block and not save the # from the finally block later.
// 2. Exceptions propagating out of the finally block. Here we need to report the line number
// from the finally block and leave the existing stack traces cleared.
// 3. Returning from the try block: Here we need to run the finally block and not update the
// line numbers.
body = AstUtils.Try(
// we use a fault to know when we have an exception and when control leaves normally (via
// either a return or the body completing successfully).
AstUtils.Try(
Parent.AddDebugInfo(AstUtils.Empty(), new SourceSpan(Span.Start, GlobalParent.IndexToLocation(HeaderIndex))),
Ast.Assign(tryThrows, AstUtils.Constant(null, typeof(Exception))),
body,
AstUtils.Empty()
).Catch(
locException,
Expression.Block(
// If there was no except block, or the except block threw, then the
// exception has not yet been properly set, so we need to set the
// currently handled exception when we catch it
Ast.Call(AstMethods.SetCurrentException, Parent.LocalContext, locException),
Ast.Assign(tryThrows, locException),
Expression.Rethrow()
)
)
).FinallyWithJumps(
// if we had an exception save the line # that was last executing during the try
AstUtils.If(
Expression.NotEqual(tryThrows, Expression.Default(typeof(Exception))),
Parent.GetSaveLineNumberExpression(tryThrows, false)
),
// clear the frames incase thae finally throws, and allow line number
// updates to proceed
UpdateLineUpdated(false),
// run the finally code
// if the finally block reraises the same exception we have been handling,
// mark it as already updated
AstUtils.Try(
@finally
).Catch(
locException,
AstUtils.If(
Expression.Equal(locException, tryThrows),
UpdateLineUpdated(true)
),
Expression.Rethrow()
),
// if we took an exception in the try block we have saved the line number. Otherwise
// we have no line number saved and will need to continue saving them if
// other exceptions are thrown.
AstUtils.If(
Expression.NotEqual(tryThrows, Expression.Default(typeof(Exception))),
UpdateLineUpdated(true)
)
);
body = Ast.Block(new[] { tryThrows }, body);
}
return(body);
}
internal override MSAst.Expression Transform(MSAst.Expression body)
{
MSAst.ParameterExpression temp = Ast.Parameter(typeof(KeyValuePair <IEnumerator, IDisposable>), "list_comprehension_for");
return(Ast.Block(
new[] { temp },
ForStatement.TransformFor(Parent, temp, _list, _lhs, body, null, Span, GlobalParent.IndexToLocation(_lhs.EndIndex), null, null, false)
));
}
public override MSAst.Expression Reduce()
{
// Temporary variable for the IEnumerator object
MSAst.ParameterExpression enumerator = Ast.Variable(typeof(KeyValuePair <IEnumerator, IDisposable>), "foreach_enumerator");
return(Ast.Block(new[] { enumerator }, TransformFor(Parent, enumerator, _list, _left, _body, _else, Span, GlobalParent.IndexToLocation(_headerIndex), _break, _continue, true)));
}
private MSAst.Expression ReduceWorker(bool optimizeDynamicConvert)
{
MSAst.Expression result;
if (_tests.Length > 100)
{
// generate:
// if(x) {
// body
// goto end
// } else {
// }
// elseBody
// end:
//
// to avoid deeply recursive trees which can stack overflow.
BlockBuilder builder = new BlockBuilder();
var label = Ast.Label();
for (int i = 0; i < _tests.Length; i++)
{
IfStatementTest ist = _tests[i];
builder.Add(
Ast.Condition(
optimizeDynamicConvert ?
TransformAndDynamicConvert(ist.Test, typeof(bool)) :
GlobalParent.Convert(typeof(bool), Microsoft.Scripting.Actions.ConversionResultKind.ExplicitCast, ist.Test),
Ast.Block(
TransformMaybeSingleLineSuite(ist.Body, GlobalParent.IndexToLocation(ist.Test.StartIndex)),
Ast.Goto(label)
),
Utils.Empty()
)
);
}
if (_else != null)
{
builder.Add(_else);
}
builder.Add(Ast.Label(label));
result = builder.ToExpression();
}
else
{
// Now build from the inside out
if (_else != null)
{
result = _else;
}
else
{
result = AstUtils.Empty();
}
int i = _tests.Length;
while (i-- > 0)
{
IfStatementTest ist = _tests[i];
result = GlobalParent.AddDebugInfoAndVoid(
Ast.Condition(
optimizeDynamicConvert ?
TransformAndDynamicConvert(ist.Test, typeof(bool)) :
GlobalParent.Convert(typeof(bool), Microsoft.Scripting.Actions.ConversionResultKind.ExplicitCast, ist.Test),
TransformMaybeSingleLineSuite(ist.Body, GlobalParent.IndexToLocation(ist.Test.StartIndex)),
result
),
new SourceSpan(GlobalParent.IndexToLocation(ist.StartIndex), GlobalParent.IndexToLocation(ist.HeaderIndex))
);
}
}
return(result);
}
public override MSAst.Expression Reduce()
{
// Temporary variable for the IEnumerator object
MSAst.ParameterExpression enumerator = Ast.Variable(typeof(KeyValuePair <IEnumerator, IDisposable>), "foreach_enumerator");
return(Ast.Block(new[] { enumerator }, TransformFor(Parent, enumerator, List, Left, Body, Else, Span, GlobalParent.IndexToLocation(HeaderIndex), ((ILoopStatement)this).BreakLabel, ((ILoopStatement)this).ContinueLabel, true)));
}