private static BoundStatement RewriteIfStatement(
CSharpSyntaxNode syntax,
ImmutableArray<LocalSymbol> locals,
BoundExpression rewrittenCondition,
BoundStatement rewrittenConsequence,
BoundStatement rewrittenAlternativeOpt,
bool hasErrors)
{
var afterif = new GeneratedLabelSymbol("afterif");
var builder = ArrayBuilder<BoundStatement>.GetInstance();
if (rewrittenAlternativeOpt == null)
{
// if (condition)
// consequence;
//
// becomes
//
// GotoIfFalse condition afterif;
// consequence;
// afterif:
builder.Add(new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, false, afterif));
builder.Add(rewrittenConsequence);
}
else
{
// if (condition)
// consequence;
// else
// alternative
//
// becomes
//
// GotoIfFalse condition alt;
// consequence
// goto afterif;
// alt:
// alternative;
// afterif:
var alt = new GeneratedLabelSymbol("alternative");
builder.Add(new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, false, alt));
builder.Add(rewrittenConsequence);
builder.Add(new BoundGotoStatement(syntax, afterif));
builder.Add(new BoundLabelStatement(syntax, alt));
builder.Add(rewrittenAlternativeOpt);
}
builder.Add(new BoundLabelStatement(syntax, afterif));
if (!locals.IsDefaultOrEmpty)
{
return new BoundBlock(syntax, locals, builder.ToImmutableAndFree(), hasErrors);
}
return new BoundStatementList(syntax, builder.ToImmutableAndFree(), hasErrors);
}
private BoundStatement RewriteWhileStatement(
BoundLoopStatement loop,
BoundExpression rewrittenCondition,
BoundStatement rewrittenBody,
GeneratedLabelSymbol breakLabel,
GeneratedLabelSymbol continueLabel,
bool hasErrors)
{
Debug.Assert(loop.Kind == BoundKind.WhileStatement || loop.Kind == BoundKind.ForEachStatement);
// while (condition)
// body;
//
// becomes
//
// goto continue;
// start:
// {
// body
// continue:
// GotoIfTrue condition start;
// }
// break:
SyntaxNode syntax = loop.Syntax;
var startLabel = new GeneratedLabelSymbol("start");
BoundStatement ifConditionGotoStart = new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, true, startLabel);
BoundStatement gotoContinue = new BoundGotoStatement(syntax, continueLabel);
if (this.Instrument && !loop.WasCompilerGenerated)
{
switch (loop.Kind)
{
case BoundKind.WhileStatement:
ifConditionGotoStart = _instrumenter.InstrumentWhileStatementConditionalGotoStartOrBreak((BoundWhileStatement)loop, ifConditionGotoStart);
break;
case BoundKind.ForEachStatement:
ifConditionGotoStart = _instrumenter.InstrumentForEachStatementConditionalGotoStart((BoundForEachStatement)loop, ifConditionGotoStart);
break;
default:
throw ExceptionUtilities.UnexpectedValue(loop.Kind);
}
// mark the initial jump as hidden. We do it to tell that this is not a part of previous statement. This
// jump may be a target of another jump (for example if loops are nested) and that would give the
// impression that the previous statement is being re-executed.
gotoContinue = new BoundSequencePoint(null, gotoContinue);
}
return BoundStatementList.Synthesized(syntax, hasErrors,
gotoContinue,
new BoundLabelStatement(syntax, startLabel),
rewrittenBody,
new BoundLabelStatement(syntax, continueLabel),
ifConditionGotoStart,
new BoundLabelStatement(syntax, breakLabel));
}
public override BoundNode VisitDoStatement(BoundDoStatement node)
{
Debug.Assert(node != null);
var rewrittenCondition = (BoundExpression)Visit(node.Condition);
var rewrittenBody = (BoundStatement)Visit(node.Body);
var startLabel = new GeneratedLabelSymbol("start");
var syntax = node.Syntax;
// EnC: We need to insert a hidden sequence point to handle function remapping in case
// the containing method is edited while methods invoked in the condition are being executed.
if (!node.WasCompilerGenerated && this.Instrument)
{
rewrittenCondition = _instrumenter.InstrumentDoStatementCondition(node, rewrittenCondition, _factory);
}
BoundStatement ifConditionGotoStart = new BoundConditionalGoto(syntax, rewrittenCondition, true, startLabel);
if (!node.WasCompilerGenerated && this.Instrument)
{
ifConditionGotoStart = _instrumenter.InstrumentDoStatementConditionalGotoStart(node, ifConditionGotoStart);
}
// do
// body
// while (condition);
//
// becomes
//
// start:
// {
// body
// continue:
// sequence point
// GotoIfTrue condition start;
// }
// break:
if (node.Locals.IsEmpty)
{
return BoundStatementList.Synthesized(syntax, node.HasErrors,
new BoundLabelStatement(syntax, startLabel),
rewrittenBody,
new BoundLabelStatement(syntax, node.ContinueLabel),
ifConditionGotoStart,
new BoundLabelStatement(syntax, node.BreakLabel));
}
return BoundStatementList.Synthesized(syntax, node.HasErrors,
new BoundLabelStatement(syntax, startLabel),
new BoundBlock(syntax,
node.Locals,
ImmutableArray.Create<BoundStatement>(rewrittenBody,
new BoundLabelStatement(syntax, node.ContinueLabel),
ifConditionGotoStart)),
new BoundLabelStatement(syntax, node.BreakLabel));
}
public override BoundNode VisitDoStatement(BoundDoStatement node)
{
Debug.Assert(node != null);
var rewrittenCondition = (BoundExpression)Visit(node.Condition);
var rewrittenBody = (BoundStatement)Visit(node.Body);
var startLabel = new GeneratedLabelSymbol("start");
var syntax = node.Syntax;
BoundStatement ifConditionGotoStart = new BoundConditionalGoto(syntax, AddConditionSequencePoint(rewrittenCondition, node), true, startLabel);
if (this.GenerateDebugInfo)
{
var doSyntax = (DoStatementSyntax)syntax;
var span = TextSpan.FromBounds(
doSyntax.WhileKeyword.SpanStart,
doSyntax.SemicolonToken.Span.End);
ifConditionGotoStart = new BoundSequencePointWithSpan(doSyntax, ifConditionGotoStart, span);
}
// do
// body
// while (condition);
//
// becomes
//
// start:
// {
// body
// continue:
// sequence point
// GotoIfTrue condition start;
// }
// break:
if (!node.InnerLocals.IsDefaultOrEmpty)
{
return BoundStatementList.Synthesized(syntax, node.HasErrors,
new BoundLabelStatement(syntax, startLabel),
new BoundBlock(syntax,
node.InnerLocals,
ImmutableArray.Create<BoundStatement>(rewrittenBody,
new BoundLabelStatement(syntax, node.ContinueLabel),
ifConditionGotoStart)),
new BoundLabelStatement(syntax, node.BreakLabel));
}
return BoundStatementList.Synthesized(syntax, node.HasErrors,
new BoundLabelStatement(syntax, startLabel),
rewrittenBody,
new BoundLabelStatement(syntax, node.ContinueLabel),
ifConditionGotoStart,
new BoundLabelStatement(syntax, node.BreakLabel));
}
private static BoundStatement RewriteIfStatement(
CSharpSyntaxNode syntax,
BoundExpression rewrittenCondition,
BoundStatement rewrittenConsequence,
BoundStatement rewrittenAlternativeOpt,
bool hasErrors)
{
var afterif = new GeneratedLabelSymbol("afterif");
// if (condition)
// consequence;
//
// becomes
//
// GotoIfFalse condition afterif;
// consequence;
// afterif:
if (rewrittenAlternativeOpt == null)
{
return BoundStatementList.Synthesized(syntax,
new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, false, afterif),
rewrittenConsequence,
new BoundLabelStatement(syntax, afterif));
}
// if (condition)
// consequence;
// else
// alternative
//
// becomes
//
// GotoIfFalse condition alt;
// consequence
// goto afterif;
// alt:
// alternative;
// afterif:
var alt = new GeneratedLabelSymbol("alternative");
return BoundStatementList.Synthesized(syntax, hasErrors,
new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, false, alt),
rewrittenConsequence,
new BoundGotoStatement(syntax, afterif),
new BoundLabelStatement(syntax, alt),
rewrittenAlternativeOpt,
new BoundLabelStatement(syntax, afterif));
}
private BoundStatement RewriteWhileStatement(
CSharpSyntaxNode syntax,
BoundExpression rewrittenCondition,
TextSpan conditionSequencePointSpan,
BoundStatement rewrittenBody,
GeneratedLabelSymbol breakLabel,
GeneratedLabelSymbol continueLabel,
bool hasErrors)
{
var startLabel = new GeneratedLabelSymbol("start");
BoundStatement ifConditionGotoStart = new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, true, startLabel);
if (this.GenerateDebugInfo)
{
ifConditionGotoStart = new BoundSequencePointWithSpan(syntax, ifConditionGotoStart, conditionSequencePointSpan);
}
// while (condition)
// body;
//
// becomes
//
// goto continue;
// start:
// {
// body
// continue:
// GotoIfTrue condition start;
// }
// break:
BoundStatement gotoContinue = new BoundGotoStatement(syntax, continueLabel);
if (this.GenerateDebugInfo)
{
// mark the initial jump as hidden. We do it to tell that this is not a part of previous statement. This
// jump may be a target of another jump (for example if loops are nested) and that would give the
// impression that the previous statement is being re-executed.
gotoContinue = new BoundSequencePoint(null, gotoContinue);
}
return BoundStatementList.Synthesized(syntax, hasErrors,
gotoContinue,
new BoundLabelStatement(syntax, startLabel),
rewrittenBody,
new BoundLabelStatement(syntax, continueLabel),
ifConditionGotoStart,
new BoundLabelStatement(syntax, breakLabel));
}
private BoundStatement MakeSwitchStatement(
CSharpSyntaxNode syntax,
BoundExpression rewrittenExpression,
ImmutableArray<BoundSwitchSection> rewrittenSections,
LabelSymbol constantTargetOpt,
ImmutableArray<LocalSymbol> locals,
GeneratedLabelSymbol breakLabel,
BoundSwitchStatement oldNode)
{
Debug.Assert(oldNode != null);
Debug.Assert((object)rewrittenExpression.Type != null);
return rewrittenExpression.Type.IsNullableType() ?
MakeSwitchStatementWithNullableExpression(syntax, rewrittenExpression, rewrittenSections, constantTargetOpt, locals, breakLabel, oldNode) :
MakeSwitchStatementWithNonNullableExpression(syntax, null, rewrittenExpression, rewrittenSections, constantTargetOpt, locals, breakLabel, oldNode);
}
public override BoundNode VisitDoStatement(BoundDoStatement node)
{
Debug.Assert(node != null);
var rewrittenCondition = (BoundExpression)Visit(node.Condition);
var rewrittenBody = (BoundStatement)Visit(node.Body);
var startLabel = new GeneratedLabelSymbol("start");
var syntax = node.Syntax;
// EnC: We need to insert a hidden sequence point to handle function remapping in case
// the containing method is edited while methods invoked in the condition are being executed.
BoundStatement ifConditionGotoStart = new BoundConditionalGoto(syntax, AddConditionSequencePoint(rewrittenCondition, node), true, startLabel);
if (this.GenerateDebugInfo)
{
var doSyntax = (DoStatementSyntax)syntax;
var span = TextSpan.FromBounds(
doSyntax.WhileKeyword.SpanStart,
doSyntax.SemicolonToken.Span.End);
ifConditionGotoStart = new BoundSequencePointWithSpan(doSyntax, ifConditionGotoStart, span);
}
// do
// body
// while (condition);
//
// becomes
//
// start:
// {
// body
// continue:
// sequence point
// GotoIfTrue condition start;
// }
// break:
return BoundStatementList.Synthesized(syntax, node.HasErrors,
new BoundLabelStatement(syntax, startLabel),
rewrittenBody,
new BoundLabelStatement(syntax, node.ContinueLabel),
ifConditionGotoStart,
new BoundLabelStatement(syntax, node.BreakLabel));
}
public BoundStatement Switch(BoundExpression ex, params BoundSwitchSection[] sections)
{
Debug.Assert(ex.Type.SpecialType != Microsoft.CodeAnalysis.SpecialType.System_String); // BoundSwitchStatement.StringEquality not set
if (sections.Length == 0) return ExpressionStatement(ex);
GeneratedLabelSymbol breakLabel = new GeneratedLabelSymbol("break");
var s = ImmutableArray.Create<BoundSwitchSection>(sections);
CheckSwitchSections(s);
return new BoundSwitchStatement(
Syntax,
ImmutableArray<LocalSymbol>.Empty,
ex,
null,
ImmutableArray<LocalSymbol>.Empty,
s,
breakLabel,
null) { WasCompilerGenerated = true };
}
public BoundStatement If(BoundExpression condition, BoundStatement thenClause, BoundStatement elseClause)
{
// We translate
// if (condition) thenClause else elseClause
// as
// {
// ConditionalGoto(!condition) alternative
// thenClause
// goto afterif;
// alternative:
// elseClause
// afterif:
// }
Debug.Assert(thenClause != null && elseClause != null);
var afterif = new GeneratedLabelSymbol("afterif");
var alt = new GeneratedLabelSymbol("alternative");
return Block(
new BoundConditionalGoto(Syntax, condition, false, alt) { WasCompilerGenerated = true },
thenClause,
Goto(afterif),
Label(alt),
elseClause,
Label(afterif)
);
}
private BoundStatement RewriteForStatement(
BoundLoopStatement original,
ImmutableArray<LocalSymbol> outerLocals,
BoundStatement rewrittenInitializer,
BoundExpression rewrittenCondition,
BoundStatement rewrittenIncrement,
BoundStatement rewrittenBody,
GeneratedLabelSymbol breakLabel,
GeneratedLabelSymbol continueLabel,
bool hasErrors)
{
Debug.Assert(original.Kind == BoundKind.ForStatement || original.Kind == BoundKind.ForEachStatement);
Debug.Assert(rewrittenBody != null);
// The sequence point behavior exhibited here is different from that of the native compiler. In the native
// compiler, if you have something like
//
// for([|int i = 0, j = 0|]; ; [|i++, j++|])
//
// then all the initializers are treated as a single sequence point, as are
// all the loop incrementors.
//
// We now make each one individually a sequence point:
//
// for([|int i = 0|], [|j = 0|]; ; [|i++|], [|j++|])
//
// If we decide that we want to preserve the native compiler stepping behavior
// then we'll need to be a bit fancy here. The initializer and increment statements
// can contain lambdas whose bodies need to have sequence points inserted, so we
// need to make sure we visit the children. But we'll also need to make sure that
// we do not generate one sequence point for each statement in the initializers
// and the incrementors.
SyntaxNode syntax = original.Syntax;
var statementBuilder = ArrayBuilder<BoundStatement>.GetInstance();
if (rewrittenInitializer != null)
{
statementBuilder.Add(rewrittenInitializer);
}
var startLabel = new GeneratedLabelSymbol("start");
// for (initializer; condition; increment)
// body;
//
// becomes the following (with block added for locals)
//
// {
// initializer;
// goto end;
// start:
// body;
// continue:
// increment;
// end:
// GotoIfTrue condition start;
// break:
// }
var endLabel = new GeneratedLabelSymbol("end");
// initializer;
// goto end;
BoundStatement gotoEnd = new BoundGotoStatement(syntax, endLabel);
if (this.Instrument)
{
switch (original.Kind)
{
case BoundKind.ForEachStatement:
gotoEnd = _instrumenter.InstrumentForEachStatementGotoEnd((BoundForEachStatement)original, gotoEnd);
break;
case BoundKind.ForStatement:
gotoEnd = _instrumenter.InstrumentForStatementGotoEnd((BoundForStatement)original, gotoEnd);
break;
default:
throw ExceptionUtilities.UnexpectedValue(original.Kind);
}
}
statementBuilder.Add(gotoEnd);
// start:
// body;
statementBuilder.Add(new BoundLabelStatement(syntax, startLabel));
statementBuilder.Add(rewrittenBody);
// continue:
// increment;
statementBuilder.Add(new BoundLabelStatement(syntax, continueLabel));
if (rewrittenIncrement != null)
{
statementBuilder.Add(rewrittenIncrement);
}
// end:
// GotoIfTrue condition start;
statementBuilder.Add(new BoundLabelStatement(syntax, endLabel));
BoundStatement branchBack = null;
if (rewrittenCondition != null)
{
branchBack = new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, true, startLabel);
}
else
{
branchBack = new BoundGotoStatement(syntax, startLabel);
}
if (this.Instrument)
{
switch (original.Kind)
{
case BoundKind.ForEachStatement:
branchBack = _instrumenter.InstrumentForEachStatementConditionalGotoStart((BoundForEachStatement)original, branchBack);
break;
case BoundKind.ForStatement:
branchBack = _instrumenter.InstrumentForStatementConditionalGotoStart((BoundForStatement)original, branchBack);
break;
default:
throw ExceptionUtilities.UnexpectedValue(original.Kind);
}
}
statementBuilder.Add(branchBack);
// break:
statementBuilder.Add(new BoundLabelStatement(syntax, breakLabel));
var statements = statementBuilder.ToImmutableAndFree();
return new BoundBlock(syntax, outerLocals, ImmutableArray<LocalFunctionSymbol>.Empty, statements, hasErrors);
}
protected SwitchBinder(Binder next, SwitchStatementSyntax switchSyntax)
: base(next)
{
SwitchSyntax = switchSyntax;
_breakLabel = new GeneratedLabelSymbol("break");
}
private BoundStatement RewriteForStatement(
CSharpSyntaxNode syntax,
ImmutableArray<LocalSymbol> outerLocals,
BoundStatement rewrittenInitializer,
ImmutableArray<LocalSymbol> innerLocals,
BoundExpression rewrittenCondition,
SyntaxNodeOrToken conditionSyntax,
BoundStatement rewrittenIncrement,
BoundStatement rewrittenBody,
GeneratedLabelSymbol breakLabel,
GeneratedLabelSymbol continueLabel,
bool hasErrors)
{
Debug.Assert(rewrittenBody != null);
// The sequence point behavior exhibited here is different from that of the native compiler. In the native
// compiler, if you have something like
//
// for(int i = 0, j = 0; ; i++, j++)
// ^--------------^ ^------^
//
// then all the initializers are treated as a single sequence point, as are
// all the loop incrementers.
//
// We now make each one individually a sequence point:
//
// for(int i = 0, j = 0; ; i++, j++)
// ^-------^ ^---^ ^-^ ^-^
//
// If we decide that we want to preserve the native compiler stepping behavior
// then we'll need to be a bit fancy here. The initializer and increment statements
// can contain lambdas whose bodies need to have sequence points inserted, so we
// need to make sure we visit the children. But we'll also need to make sure that
// we do not generate one sequence point for each statement in the initializers
// and the incrementers.
var statementBuilder = ArrayBuilder<BoundStatement>.GetInstance();
if (rewrittenInitializer != null)
{
statementBuilder.Add(rewrittenInitializer);
}
var startLabel = new GeneratedLabelSymbol("start");
if (!innerLocals.IsDefaultOrEmpty)
{
var walker = new AnyLocalCapturedInALambdaWalker(innerLocals);
if (walker.Analyze(rewrittenCondition) || walker.Analyze(rewrittenIncrement) || walker.Analyze(rewrittenBody))
{
// If any inner local is captured within a lambda, we need to enter scope-block
// always from the top, that is where an instance of a display class will be created.
// The IL will be less optimal, but this shouldn't be a problem, given presence of lambdas.
// for (initializer; condition; increment)
// body;
//
// becomes the following (with
// block added for locals)
//
// {
// initializer;
// start:
// {
// GotoIfFalse condition break;
// body;
// continue:
// increment;
// goto start;
// }
// break:
// }
// start:
statementBuilder.Add(new BoundLabelStatement(syntax, startLabel));
var blockBuilder = ArrayBuilder<BoundStatement>.GetInstance();
// GotoIfFalse condition break;
if (rewrittenCondition != null)
{
BoundStatement ifNotConditionGotoBreak = new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, false, breakLabel);
if (this.generateDebugInfo)
{
if (conditionSyntax.IsToken)
{
ifNotConditionGotoBreak = new BoundSequencePointWithSpan(syntax, ifNotConditionGotoBreak, conditionSyntax.Span);
}
else
{
ifNotConditionGotoBreak = new BoundSequencePoint((CSharpSyntaxNode)conditionSyntax.AsNode(), ifNotConditionGotoBreak);
}
}
blockBuilder.Add(ifNotConditionGotoBreak);
}
// body;
blockBuilder.Add(rewrittenBody);
// continue:
// increment;
blockBuilder.Add(new BoundLabelStatement(syntax, continueLabel));
if (rewrittenIncrement != null)
{
blockBuilder.Add(rewrittenIncrement);
}
// goto start;
blockBuilder.Add(new BoundGotoStatement(syntax, startLabel));
statementBuilder.Add(new BoundBlock(syntax, innerLocals, blockBuilder.ToImmutableAndFree()));
// break:
statementBuilder.Add(new BoundLabelStatement(syntax, breakLabel));
return new BoundBlock(syntax, outerLocals, statementBuilder.ToImmutableAndFree(), hasErrors);
}
}
var endLabel = new GeneratedLabelSymbol("end");
// for (initializer; condition; increment)
// body;
//
// becomes the following (with
// block added for locals)
//
// {
// initializer;
// goto end;
// start:
// body;
// continue:
// increment;
// end:
// GotoIfTrue condition start;
// break:
// }
// initializer;
// goto end;
//mark the initial jump as hidden.
//We do it to tell that this is not a part of previous statement.
//This jump may be a target of another jump (for example if loops are nested) and that will make
//impression of the previous statement being re-executed
var gotoEnd = new BoundSequencePoint(null, new BoundGotoStatement(syntax, endLabel));
statementBuilder.Add(gotoEnd);
// start:
// body;
statementBuilder.Add(new BoundLabelStatement(syntax, startLabel));
ArrayBuilder<BoundStatement> saveBuilder = null;
if (!innerLocals.IsDefaultOrEmpty)
{
saveBuilder = statementBuilder;
statementBuilder = ArrayBuilder<BoundStatement>.GetInstance();
}
statementBuilder.Add(rewrittenBody);
// continue:
// increment;
statementBuilder.Add(new BoundLabelStatement(syntax, continueLabel));
if (rewrittenIncrement != null)
{
statementBuilder.Add(rewrittenIncrement);
}
// end:
// GotoIfTrue condition start;
statementBuilder.Add(new BoundLabelStatement(syntax, endLabel));
BoundStatement branchBack = null;
if (rewrittenCondition != null)
{
branchBack = new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, true, startLabel);
}
else
{
branchBack = new BoundGotoStatement(syntax, startLabel);
}
if (this.generateDebugInfo)
{
if (conditionSyntax.IsToken)
{
branchBack = new BoundSequencePointWithSpan(syntax, branchBack, conditionSyntax.Span);
}
else
{
//if there is no condition, make this a hidden point so that
//it does not count as a part of previous statement
branchBack = new BoundSequencePoint((CSharpSyntaxNode)conditionSyntax.AsNode(), branchBack);
}
}
statementBuilder.Add(branchBack);
if (!innerLocals.IsDefaultOrEmpty)
{
var block = new BoundBlock(syntax, innerLocals, statementBuilder.ToImmutableAndFree());
statementBuilder = saveBuilder;
statementBuilder.Add(block);
}
// break:
statementBuilder.Add(new BoundLabelStatement(syntax, breakLabel));
var statements = statementBuilder.ToImmutableAndFree();
return new BoundBlock(syntax, outerLocals, statements, hasErrors);
}
private static LabelSymbol GetNullValueTargetSwitchLabel(ImmutableArray<BoundSwitchSection> sections, GeneratedLabelSymbol breakLabel)
{
LabelSymbol fallThroughLabel = breakLabel;
foreach (var section in sections)
{
foreach (BoundSwitchLabel boundLabel in section.BoundSwitchLabels)
{
var label = (SourceLabelSymbol)boundLabel.Label;
var labelConstant = label.SwitchCaseLabelConstant;
if (labelConstant == ConstantValue.Null)
{
return label;
}
else if (labelConstant == null)
{
// Default label
Debug.Assert(label.IdentifierNodeOrToken.Kind() == SyntaxKind.DefaultSwitchLabel);
Debug.Assert(fallThroughLabel == breakLabel);
fallThroughLabel = label;
}
}
}
return fallThroughLabel;
}
private GeneratedLabelSymbol GetLabelClone(LabelSymbol label)
{
var labelClones = _labelClones;
if (labelClones == null)
{
_labelClones = labelClones = new Dictionary<LabelSymbol, GeneratedLabelSymbol>();
}
GeneratedLabelSymbol clone;
if (!labelClones.TryGetValue(label, out clone))
{
clone = new GeneratedLabelSymbol("cloned_" + label.Name);
labelClones.Add(label, clone);
}
return clone;
}
private BoundStatement MakeSwitchStatementWithNonNullableExpression(
CSharpSyntaxNode syntax,
BoundStatement preambleOpt,
BoundExpression rewrittenExpression,
ImmutableArray<BoundSwitchSection> rewrittenSections,
LabelSymbol constantTargetOpt,
ImmutableArray<LocalSymbol> locals,
GeneratedLabelSymbol breakLabel,
BoundSwitchStatement oldNode)
{
Debug.Assert(!rewrittenExpression.Type.IsNullableType());
Debug.Assert((object)oldNode.StringEquality == null);
// If we are emitting a hash table based string switch,
// we need to generate a helper method for computing
// string hash value in <PrivateImplementationDetails> class.
MethodSymbol stringEquality = null;
if (rewrittenExpression.Type.SpecialType == SpecialType.System_String)
{
EnsureStringHashFunction(rewrittenSections, syntax);
stringEquality = GetSpecialTypeMethod(syntax, SpecialMember.System_String__op_Equality);
}
return oldNode.Update(
loweredPreambleOpt: preambleOpt,
boundExpression: rewrittenExpression,
constantTargetOpt: constantTargetOpt,
innerLocals: locals,
switchSections: rewrittenSections,
breakLabel: breakLabel,
stringEquality: stringEquality);
}
/// <summary>
/// Generate a thread-safe accessor for a regular field-like event.
///
/// DelegateType tmp0 = _event; //backing field
/// DelegateType tmp1;
/// DelegateType tmp2;
/// do {
/// tmp1 = tmp0;
/// tmp2 = (DelegateType)Delegate.Combine(tmp1, value); //Remove for -=
/// tmp0 = Interlocked.CompareExchange<DelegateType>(ref _event, tmp2, tmp1);
/// } while ((object)tmp0 != (object)tmp1);
/// </summary>
internal static BoundBlock ConstructFieldLikeEventAccessorBody_Regular(SourceEventSymbol eventSymbol, bool isAddMethod, CSharpCompilation compilation, DiagnosticBag diagnostics)
{
CSharpSyntaxNode syntax = eventSymbol.CSharpSyntaxNode;
TypeSymbol delegateType = eventSymbol.Type;
MethodSymbol accessor = isAddMethod ? eventSymbol.AddMethod : eventSymbol.RemoveMethod;
ParameterSymbol thisParameter = accessor.ThisParameter;
TypeSymbol boolType = compilation.GetSpecialType(SpecialType.System_Boolean);
MethodSymbol updateMethod = (MethodSymbol)compilation.GetSpecialTypeMember(isAddMethod ? SpecialMember.System_Delegate__Combine : SpecialMember.System_Delegate__Remove);
MethodSymbol compareExchangeMethod = GetConstructedCompareExchangeMethod(delegateType, compilation, accessor.Locations[0], diagnostics);
if ((object)compareExchangeMethod == null)
{
return new BoundBlock(syntax,
locals: ImmutableArray<LocalSymbol>.Empty,
statements: ImmutableArray.Create<BoundStatement>(
new BoundReturnStatement(syntax,
expressionOpt: null)
{ WasCompilerGenerated = true }))
{ WasCompilerGenerated = true };
}
GeneratedLabelSymbol loopLabel = new GeneratedLabelSymbol("loop");
const int numTemps = 3;
LocalSymbol[] tmps = new LocalSymbol[numTemps];
BoundLocal[] boundTmps = new BoundLocal[numTemps];
for (int i = 0; i < numTemps; i++)
{
tmps[i] = new SynthesizedLocal(accessor, delegateType, SynthesizedLocalKind.LoweringTemp);
boundTmps[i] = new BoundLocal(syntax, tmps[i], null, delegateType);
}
BoundThisReference fieldReceiver = eventSymbol.IsStatic ?
null :
new BoundThisReference(syntax, thisParameter.Type) { WasCompilerGenerated = true };
BoundFieldAccess boundBackingField = new BoundFieldAccess(syntax,
receiver: fieldReceiver,
fieldSymbol: eventSymbol.AssociatedField,
constantValueOpt: null)
{ WasCompilerGenerated = true };
BoundParameter boundParameter = new BoundParameter(syntax,
parameterSymbol: accessor.Parameters[0])
{ WasCompilerGenerated = true };
// tmp0 = _event;
BoundStatement tmp0Init = new BoundExpressionStatement(syntax,
expression: new BoundAssignmentOperator(syntax,
left: boundTmps[0],
right: boundBackingField,
type: delegateType)
{ WasCompilerGenerated = true })
{ WasCompilerGenerated = true };
// LOOP:
BoundStatement loopStart = new BoundLabelStatement(syntax,
label: loopLabel)
{ WasCompilerGenerated = true };
// tmp1 = tmp0;
BoundStatement tmp1Update = new BoundExpressionStatement(syntax,
expression: new BoundAssignmentOperator(syntax,
left: boundTmps[1],
right: boundTmps[0],
type: delegateType)
{ WasCompilerGenerated = true })
{ WasCompilerGenerated = true };
// (DelegateType)Delegate.Combine(tmp1, value)
BoundExpression delegateUpdate = BoundConversion.SynthesizedNonUserDefined(syntax,
operand: BoundCall.Synthesized(syntax,
receiverOpt: null,
method: updateMethod,
arguments: ImmutableArray.Create<BoundExpression>(boundTmps[1], boundParameter)),
kind: ConversionKind.ExplicitReference,
type: delegateType);
// tmp2 = (DelegateType)Delegate.Combine(tmp1, value);
BoundStatement tmp2Update = new BoundExpressionStatement(syntax,
expression: new BoundAssignmentOperator(syntax,
left: boundTmps[2],
right: delegateUpdate,
type: delegateType)
{ WasCompilerGenerated = true })
{ WasCompilerGenerated = true };
// Interlocked.CompareExchange<DelegateType>(ref _event, tmp2, tmp1)
BoundExpression compareExchange = BoundCall.Synthesized(syntax,
receiverOpt: null,
method: compareExchangeMethod,
arguments: ImmutableArray.Create<BoundExpression>(boundBackingField, boundTmps[2], boundTmps[1]));
// tmp0 = Interlocked.CompareExchange<DelegateType>(ref _event, tmp2, tmp1);
BoundStatement tmp0Update = new BoundExpressionStatement(syntax,
expression: new BoundAssignmentOperator(syntax,
left: boundTmps[0],
right: compareExchange,
type: delegateType)
{ WasCompilerGenerated = true })
{ WasCompilerGenerated = true };
// tmp0 == tmp1 // i.e. exit when they are equal, jump to start otherwise
BoundExpression loopExitCondition = new BoundBinaryOperator(syntax,
operatorKind: BinaryOperatorKind.ObjectEqual,
left: boundTmps[0],
right: boundTmps[1],
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: boolType)
{ WasCompilerGenerated = true };
// branchfalse (tmp0 == tmp1) LOOP
BoundStatement loopEnd = new BoundConditionalGoto(syntax,
condition: loopExitCondition,
jumpIfTrue: false,
label: loopLabel)
{ WasCompilerGenerated = true };
BoundStatement @return = new BoundReturnStatement(syntax,
expressionOpt: null)
{ WasCompilerGenerated = true };
return new BoundBlock(syntax,
locals: tmps.AsImmutable(),
statements: ImmutableArray.Create<BoundStatement>(
tmp0Init,
loopStart,
tmp1Update,
tmp2Update,
tmp0Update,
loopEnd,
@return))
{ WasCompilerGenerated = true };
}
private BoundStatement RewriteForStatement(
BoundForStatement node,
BoundStatement rewrittenInitializer,
BoundExpression rewrittenCondition,
BoundStatement rewrittenIncrement,
BoundStatement rewrittenBody)
{
if (node.InnerLocals.IsEmpty)
{
return RewriteForStatementWithoutInnerLocals(
node,
node.OuterLocals,
rewrittenInitializer,
rewrittenCondition,
rewrittenIncrement,
rewrittenBody,
node.BreakLabel,
node.ContinueLabel, node.HasErrors);
}
// We need to enter inner_scope-block from the top, that is where an instance of a display class will be created
// if any local is captured within a lambda.
// for (initializer; condition; increment)
// body;
//
// becomes the following (with block added for locals)
//
// {
// initializer;
// start:
// {
// GotoIfFalse condition break;
// body;
// continue:
// increment;
// goto start;
// }
// break:
// }
Debug.Assert(rewrittenBody != null);
SyntaxNode syntax = node.Syntax;
var statementBuilder = ArrayBuilder<BoundStatement>.GetInstance();
// initializer;
if (rewrittenInitializer != null)
{
statementBuilder.Add(rewrittenInitializer);
}
var startLabel = new GeneratedLabelSymbol("start");
// start:
BoundStatement startLabelStatement = new BoundLabelStatement(syntax, startLabel);
if (Instrument)
{
startLabelStatement = new BoundSequencePoint(null, startLabelStatement);
}
statementBuilder.Add(startLabelStatement);
var blockBuilder = ArrayBuilder<BoundStatement>.GetInstance();
// GotoIfFalse condition break;
if (rewrittenCondition != null)
{
BoundStatement ifNotConditionGotoBreak = new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, false, node.BreakLabel);
if (this.Instrument)
{
ifNotConditionGotoBreak = _instrumenter.InstrumentForStatementConditionalGotoStartOrBreak(node, ifNotConditionGotoBreak);
}
blockBuilder.Add(ifNotConditionGotoBreak);
}
// body;
blockBuilder.Add(rewrittenBody);
// continue:
// increment;
blockBuilder.Add(new BoundLabelStatement(syntax, node.ContinueLabel));
if (rewrittenIncrement != null)
{
blockBuilder.Add(rewrittenIncrement);
}
// goto start;
blockBuilder.Add(new BoundGotoStatement(syntax, startLabel));
statementBuilder.Add(new BoundBlock(syntax, node.InnerLocals, blockBuilder.ToImmutableAndFree()));
// break:
statementBuilder.Add(new BoundLabelStatement(syntax, node.BreakLabel));
var statements = statementBuilder.ToImmutableAndFree();
return new BoundBlock(syntax, node.OuterLocals, statements, node.HasErrors);
}
protected LoopBinder(MethodSymbol owner, Binder enclosing)
: base(owner, enclosing)
{
this.breakLabel = new GeneratedLabelSymbol("break");
this.continueLabel = new GeneratedLabelSymbol("continue");
}
protected LoopBinder(Binder enclosing)
: base(enclosing)
{
_breakLabel = new GeneratedLabelSymbol("break");
_continueLabel = new GeneratedLabelSymbol("continue");
}
private BoundStatement RewriteWhileStatement(
CSharpSyntaxNode syntax,
ImmutableArray<LocalSymbol> innerLocals,
BoundExpression rewrittenCondition,
TextSpan conditionSequencePointSpan,
BoundStatement rewrittenBody,
GeneratedLabelSymbol breakLabel,
GeneratedLabelSymbol continueLabel,
bool hasErrors)
{
if (!innerLocals.IsDefaultOrEmpty)
{
var walker = new AnyLocalCapturedInALambdaWalker(innerLocals);
if (walker.Analyze(rewrittenCondition) || walker.Analyze(rewrittenBody))
{
// If any inner local is captured within a lambda, we need to enter scope-block
// always from the top, that is where an instance of a display class will be created.
// The IL will be less optimal, but this shouldn't be a problem, given presence of lambdas.
// while (condition)
// body;
//
// becomes
//
// continue:
// {
// GotoIfFalse condition break;
// body
// goto continue;
// }
// break:
// TODO: We could perform more fine analysis.
// If locals declared in condition (the innerLocals) are captured, but not referenced in the body, we could use optimal IL by creating
// another block around the condition and use it as a scope for the locals declared in condition.
// This optimization can be applied to 'for' as well, while-body === for-body + increment.
// Note however that the scope adjusments will likely be observable during debugging, in locals window.
BoundStatement ifNotConditionGotoBreak = new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, false, breakLabel);
if (this.GenerateDebugInfo)
{
ifNotConditionGotoBreak = new BoundSequencePointWithSpan(syntax, ifNotConditionGotoBreak, conditionSequencePointSpan);
}
return BoundStatementList.Synthesized(syntax, hasErrors,
new BoundLabelStatement(syntax, continueLabel),
new BoundBlock(syntax,
innerLocals,
ImmutableArray.Create(
ifNotConditionGotoBreak,
rewrittenBody,
new BoundGotoStatement(syntax, continueLabel))),
new BoundLabelStatement(syntax, breakLabel));
}
}
var startLabel = new GeneratedLabelSymbol("start");
BoundStatement ifConditionGotoStart = new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, true, startLabel);
if (this.GenerateDebugInfo)
{
ifConditionGotoStart = new BoundSequencePointWithSpan(syntax, ifConditionGotoStart, conditionSequencePointSpan);
}
// while (condition)
// body;
//
// becomes
//
// goto continue;
// start:
// {
// body
// continue:
// GotoIfTrue condition start;
// }
// break:
BoundStatement gotoContinue = new BoundGotoStatement(syntax, continueLabel);
if (this.GenerateDebugInfo)
{
// mark the initial jump as hidden. We do it to tell that this is not a part of previous statement. This
// jump may be a target of another jump (for example if loops are nested) and that would give the
// impression that the previous statement is being re-executed.
gotoContinue = new BoundSequencePoint(null, gotoContinue);
}
if (!innerLocals.IsDefaultOrEmpty)
{
return BoundStatementList.Synthesized(syntax, hasErrors,
gotoContinue,
new BoundLabelStatement(syntax, startLabel),
new BoundBlock(syntax,
innerLocals,
ImmutableArray.Create<BoundStatement>(
rewrittenBody,
new BoundLabelStatement(syntax, continueLabel),
ifConditionGotoStart)),
new BoundLabelStatement(syntax, breakLabel));
}
return BoundStatementList.Synthesized(syntax, hasErrors,
gotoContinue,
new BoundLabelStatement(syntax, startLabel),
rewrittenBody,
new BoundLabelStatement(syntax, continueLabel),
ifConditionGotoStart,
new BoundLabelStatement(syntax, breakLabel));
}
protected void AddState(out int stateNumber, out GeneratedLabelSymbol resumeLabel)
{
stateNumber = nextState++;
if (dispatches == null)
{
dispatches = new Dictionary<LabelSymbol, List<int>>();
}
if (this.useFinalizerBookkeeping && !hasFinalizerState)
{
currentFinalizerState = nextState++;
hasFinalizerState = true;
}
resumeLabel = F.GenerateLabel("stateMachine");
List<int> states = new List<int>();
states.Add(stateNumber);
dispatches.Add(resumeLabel, states);
if (this.useFinalizerBookkeeping)
{
finalizerStateMap.Add(stateNumber, currentFinalizerState);
}
}
private void EmitSwitchBody(
ImmutableArray<LocalSymbol> locals,
ImmutableArray<BoundSwitchSection> switchSections,
GeneratedLabelSymbol breakLabel,
SyntaxNode syntaxNode)
{
var hasLocals = !locals.IsEmpty;
if (hasLocals)
{
_builder.OpenLocalScope();
foreach (var local in locals)
{
DefineLocal(local, syntaxNode);
}
}
foreach (var section in switchSections)
{
EmitSwitchSection(section);
}
_builder.MarkLabel(breakLabel);
if (hasLocals)
{
_builder.CloseLocalScope();
}
}
private BoundStatement RewriteForStatement(
CSharpSyntaxNode syntax,
ImmutableArray<LocalSymbol> outerLocals,
BoundStatement rewrittenInitializer,
BoundExpression rewrittenCondition,
CSharpSyntaxNode conditionSyntaxOpt,
TextSpan conditionSpanOpt,
BoundStatement rewrittenIncrement,
BoundStatement rewrittenBody,
GeneratedLabelSymbol breakLabel,
GeneratedLabelSymbol continueLabel,
bool hasErrors)
{
Debug.Assert(rewrittenBody != null);
// The sequence point behavior exhibited here is different from that of the native compiler. In the native
// compiler, if you have something like
//
// for([|int i = 0, j = 0|]; ; [|i++, j++|])
//
// then all the initializers are treated as a single sequence point, as are
// all the loop incrementors.
//
// We now make each one individually a sequence point:
//
// for([|int i = 0|], [|j = 0|]; ; [|i++|], [|j++|])
//
// If we decide that we want to preserve the native compiler stepping behavior
// then we'll need to be a bit fancy here. The initializer and increment statements
// can contain lambdas whose bodies need to have sequence points inserted, so we
// need to make sure we visit the children. But we'll also need to make sure that
// we do not generate one sequence point for each statement in the initializers
// and the incrementors.
var statementBuilder = ArrayBuilder<BoundStatement>.GetInstance();
if (rewrittenInitializer != null)
{
statementBuilder.Add(rewrittenInitializer);
}
var startLabel = new GeneratedLabelSymbol("start");
// for (initializer; condition; increment)
// body;
//
// becomes the following (with block added for locals)
//
// {
// initializer;
// goto end;
// start:
// body;
// continue:
// increment;
// end:
// GotoIfTrue condition start;
// break:
// }
var endLabel = new GeneratedLabelSymbol("end");
// initializer;
// goto end;
// Mark the initial jump as hidden.
// We do it to tell that this is not a part of previous statement.
// This jump may be a target of another jump (for example if loops are nested) and that will make
// impression of the previous statement being re-executed
var gotoEnd = new BoundSequencePoint(null, new BoundGotoStatement(syntax, endLabel));
statementBuilder.Add(gotoEnd);
// start:
// body;
statementBuilder.Add(new BoundLabelStatement(syntax, startLabel));
statementBuilder.Add(rewrittenBody);
// continue:
// increment;
statementBuilder.Add(new BoundLabelStatement(syntax, continueLabel));
if (rewrittenIncrement != null)
{
statementBuilder.Add(rewrittenIncrement);
}
// end:
// GotoIfTrue condition start;
statementBuilder.Add(new BoundLabelStatement(syntax, endLabel));
BoundStatement branchBack = null;
if (rewrittenCondition != null)
{
branchBack = new BoundConditionalGoto(rewrittenCondition.Syntax, rewrittenCondition, true, startLabel);
}
else
{
branchBack = new BoundGotoStatement(syntax, startLabel);
}
if (this.GenerateDebugInfo)
{
if (!conditionSpanOpt.IsEmpty)
{
branchBack = new BoundSequencePointWithSpan(syntax, branchBack, conditionSpanOpt);
}
else
{
// hidden sequence point if there is no condition
branchBack = new BoundSequencePoint(conditionSyntaxOpt, branchBack);
}
}
statementBuilder.Add(branchBack);
// break:
statementBuilder.Add(new BoundLabelStatement(syntax, breakLabel));
var statements = statementBuilder.ToImmutableAndFree();
return new BoundBlock(syntax, outerLocals, statements, hasErrors);
}
private BoundStatement MakeSwitchStatementWithNullableExpression(
CSharpSyntaxNode syntax,
BoundExpression rewrittenExpression,
ImmutableArray<BoundSwitchSection> rewrittenSections,
LabelSymbol constantTargetOpt,
ImmutableArray<LocalSymbol> locals,
GeneratedLabelSymbol breakLabel,
BoundSwitchStatement oldNode)
{
Debug.Assert(rewrittenExpression.Type.IsNullableType());
var exprSyntax = rewrittenExpression.Syntax;
var exprNullableType = rewrittenExpression.Type;
var statementBuilder = ArrayBuilder<BoundStatement>.GetInstance();
// Rewrite the nullable expression to a temp as we might have a user defined conversion from source expression to switch governing type.
// We can avoid generating the temp if the expression is a bound local.
LocalSymbol tempLocal;
if (rewrittenExpression.Kind != BoundKind.Local)
{
BoundAssignmentOperator assignmentToTemp;
BoundLocal boundTemp = _factory.StoreToTemp(rewrittenExpression, out assignmentToTemp);
var tempAssignment = new BoundExpressionStatement(exprSyntax, assignmentToTemp);
statementBuilder.Add(tempAssignment);
tempLocal = boundTemp.LocalSymbol;
rewrittenExpression = boundTemp;
}
else
{
tempLocal = null;
}
// Generate a BoundConditionalGoto with null check as the conditional expression and appropriate switch label as the target: null, default or exit label.
BoundStatement condGotoNullValueTargetLabel = new BoundConditionalGoto(
exprSyntax,
condition: MakeNullCheck(exprSyntax, rewrittenExpression, BinaryOperatorKind.NullableNullEqual),
jumpIfTrue: true,
label: GetNullValueTargetSwitchLabel(rewrittenSections, breakLabel));
// Rewrite the switch statement using nullable expression's underlying value as the switch expression.
// rewrittenExpression.GetValueOrDefault()
MethodSymbol getValueOrDefault = GetNullableMethod(syntax, exprNullableType, SpecialMember.System_Nullable_T_GetValueOrDefault);
BoundCall callGetValueOrDefault = BoundCall.Synthesized(exprSyntax, rewrittenExpression, getValueOrDefault);
rewrittenExpression = callGetValueOrDefault;
// rewrite switch statement
BoundStatement rewrittenSwitchStatement = MakeSwitchStatementWithNonNullableExpression(
syntax,
condGotoNullValueTargetLabel,
rewrittenExpression,
rewrittenSections,
constantTargetOpt,
locals,
breakLabel,
oldNode);
statementBuilder.Add(rewrittenSwitchStatement);
return new BoundBlock(syntax, locals: (object)tempLocal == null ? ImmutableArray<LocalSymbol>.Empty : ImmutableArray.Create<LocalSymbol>(tempLocal), statements: statementBuilder.ToImmutableAndFree());
}
public LabelSymbol ProxyReturnIfNeeded(
MethodSymbol containingMethod,
BoundExpression valueOpt,
out SynthesizedLocal returnValue)
{
returnValue = null;
// no need to proxy returns at the root
if (this.IsRoot())
{
return null;
}
var returnProxy = this.returnProxyLabel;
if (returnProxy == null)
{
this.returnProxyLabel = returnProxy = new GeneratedLabelSymbol("returnProxy");
}
if (valueOpt != null)
{
returnValue = this.returnValue;
if (returnValue == null)
{
Debug.Assert(_tryStatementSyntaxOpt != null);
this.returnValue = returnValue = new SynthesizedLocal(containingMethod, valueOpt.Type, SynthesizedLocalKind.AsyncMethodReturnValue, _tryStatementSyntaxOpt);
}
}
return returnProxy;
}
public BoundStatement If(BoundExpression condition, ImmutableArray<LocalSymbol> locals, BoundStatement thenClause, BoundStatement elseClauseOpt = null)
{
// We translate
// if (condition) thenClause else elseClause
// as
// {
// ConditionalGoto(!condition) alternative
// thenClause
// goto afterif;
// alternative:
// elseClause
// afterif:
// }
Debug.Assert(thenClause != null);
var statements = ArrayBuilder<BoundStatement>.GetInstance();
var afterif = new GeneratedLabelSymbol("afterif");
if (elseClauseOpt != null)
{
var alt = new GeneratedLabelSymbol("alternative");
statements.Add(new BoundConditionalGoto(Syntax, condition, false, alt) { WasCompilerGenerated = true });
statements.Add(thenClause);
statements.Add(Goto(afterif));
if (!locals.IsDefaultOrEmpty)
{
var firstPart = this.Block(locals, statements.ToImmutable());
statements.Clear();
statements.Add(firstPart);
}
statements.Add(Label(alt));
statements.Add(elseClauseOpt);
}
else
{
statements.Add(new BoundConditionalGoto(Syntax, condition, false, afterif) { WasCompilerGenerated = true });
statements.Add(thenClause);
if (!locals.IsDefaultOrEmpty)
{
var firstPart = this.Block(locals, statements.ToImmutable());
statements.Clear();
statements.Add(firstPart);
}
}
statements.Add(Label(afterif));
return Block(statements.ToImmutableAndFree());
}
internal SwitchBinder(Binder next, SwitchStatementSyntax switchSyntax)
: base(next)
{
this.switchSyntax = switchSyntax;
this.breakLabel = new GeneratedLabelSymbol("break");
}
// returns a proxy for a label if branch must be hijacked to run finally
// otherwise returns same label back
public LabelSymbol ProxyLabelIfNeeded(LabelSymbol label)
{
// no need to proxy a label in the current frame or when we are at the root
if (this.IsRoot() || (labels != null && labels.Contains(label)))
{
return label;
}
var proxyLabels = this.proxyLabels;
if (proxyLabels == null)
{
this.proxyLabels = proxyLabels = new Dictionary<LabelSymbol, LabelSymbol>();
}
LabelSymbol proxy;
if (!proxyLabels.TryGetValue(label, out proxy))
{
proxy = new GeneratedLabelSymbol("proxy" + label.Name);
proxyLabels.Add(label, proxy);
}
return proxy;
}
/// <summary>
/// Lower a foreach loop that will enumerate a multi-dimensional array.
///
/// A[...] a = x;
/// int q_0 = a.GetUpperBound(0), q_1 = a.GetUpperBound(1), ...;
/// for (int p_0 = a.GetLowerBound(0); p_0 <= q_0; p_0 = p_0 + 1)
/// for (int p_1 = a.GetLowerBound(1); p_1 <= q_1; p_1 = p_1 + 1)
/// ...
/// { V v = (V)a[p_0, p_1, ...]; /* body */ }
/// </summary>
/// <remarks>
/// We will follow Dev10 in diverging from the C# 4 spec by ignoring Array's
/// implementation of IEnumerable and just indexing into its elements.
///
/// NOTE: We're assuming that sequence points have already been generated.
/// Otherwise, lowering to nested for-loops would generated spurious ones.
/// </remarks>
private BoundStatement RewriteMultiDimensionalArrayForEachStatement(BoundForEachStatement node)
{
ForEachStatementSyntax forEachSyntax = (ForEachStatementSyntax)node.Syntax;
BoundExpression collectionExpression = GetUnconvertedCollectionExpression(node);
Debug.Assert(collectionExpression.Type.IsArray());
ArrayTypeSymbol arrayType = (ArrayTypeSymbol)collectionExpression.Type;
int rank = arrayType.Rank;
Debug.Assert(!arrayType.IsSZArray);
TypeSymbol intType = _compilation.GetSpecialType(SpecialType.System_Int32);
TypeSymbol boolType = _compilation.GetSpecialType(SpecialType.System_Boolean);
// Values we'll use every iteration
MethodSymbol getLowerBoundMethod = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_Array__GetLowerBound);
MethodSymbol getUpperBoundMethod = GetSpecialTypeMethod(forEachSyntax, SpecialMember.System_Array__GetUpperBound);
BoundExpression rewrittenExpression = (BoundExpression)Visit(collectionExpression);
BoundStatement rewrittenBody = (BoundStatement)Visit(node.Body);
// A[...] a
LocalSymbol arrayVar = _factory.SynthesizedLocal(arrayType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArray);
BoundLocal boundArrayVar = MakeBoundLocal(forEachSyntax, arrayVar, arrayType);
// A[...] a = /*node.Expression*/;
BoundStatement arrayVarDecl = MakeLocalDeclaration(forEachSyntax, arrayVar, rewrittenExpression);
AddForEachExpressionSequencePoint(forEachSyntax, ref arrayVarDecl);
// NOTE: dev10 initializes all of the upper bound temps before entering the loop (as opposed to
// initializing each one at the corresponding level of nesting). Doing it at the same time as
// the lower bound would make this code a bit simpler, but it would make it harder to compare
// the roslyn and dev10 IL.
// int q_0, q_1, ...
LocalSymbol[] upperVar = new LocalSymbol[rank];
BoundLocal[] boundUpperVar = new BoundLocal[rank];
BoundStatement[] upperVarDecl = new BoundStatement[rank];
for (int dimension = 0; dimension < rank; dimension++)
{
// int q_dimension
upperVar[dimension] = _factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayLimit);
boundUpperVar[dimension] = MakeBoundLocal(forEachSyntax, upperVar[dimension], intType);
ImmutableArray<BoundExpression> dimensionArgument = ImmutableArray.Create(
MakeLiteral(forEachSyntax,
constantValue: ConstantValue.Create(dimension, ConstantValueTypeDiscriminator.Int32),
type: intType));
// a.GetUpperBound(dimension)
BoundExpression currentDimensionUpperBound = BoundCall.Synthesized(forEachSyntax, boundArrayVar, getUpperBoundMethod, dimensionArgument);
// int q_dimension = a.GetUpperBound(dimension);
upperVarDecl[dimension] = MakeLocalDeclaration(forEachSyntax, upperVar[dimension], currentDimensionUpperBound);
}
// int p_0, p_1, ...
LocalSymbol[] positionVar = new LocalSymbol[rank];
BoundLocal[] boundPositionVar = new BoundLocal[rank];
for (int dimension = 0; dimension < rank; dimension++)
{
positionVar[dimension] = _factory.SynthesizedLocal(intType, syntax: forEachSyntax, kind: SynthesizedLocalKind.ForEachArrayIndex);
boundPositionVar[dimension] = MakeBoundLocal(forEachSyntax, positionVar[dimension], intType);
}
// V v
LocalSymbol iterationVar = node.IterationVariable;
TypeSymbol iterationVarType = iterationVar.Type;
// (V)a[p_0, p_1, ...]
BoundExpression iterationVarInitValue = MakeConversion(
syntax: forEachSyntax,
rewrittenOperand: new BoundArrayAccess(forEachSyntax,
expression: boundArrayVar,
indices: ImmutableArray.Create((BoundExpression[])boundPositionVar),
type: arrayType.ElementType),
conversion: node.ElementConversion,
rewrittenType: iterationVarType,
@checked: node.Checked);
// V v = (V)a[p_0, p_1, ...];
BoundStatement iterationVarDecl = MakeLocalDeclaration(forEachSyntax, iterationVar, iterationVarInitValue);
AddForEachIterationVariableSequencePoint(forEachSyntax, ref iterationVarDecl);
// { V v = (V)a[p_0, p_1, ...]; /* node.Body */ }
BoundStatement innermostLoopBody = CreateBlockDeclaringIterationVariable(iterationVar, iterationVarDecl, rewrittenBody, forEachSyntax);
// work from most-nested to least-nested
// for (int p_0 = a.GetLowerBound(0); p_0 <= q_0; p_0 = p_0 + 1)
// for (int p_1 = a.GetLowerBound(0); p_1 <= q_1; p_1 = p_1 + 1)
// ...
// { V v = (V)a[p_0, p_1, ...]; /* node.Body */ }
BoundStatement forLoop = null;
for (int dimension = rank - 1; dimension >= 0; dimension--)
{
ImmutableArray<BoundExpression> dimensionArgument = ImmutableArray.Create(
MakeLiteral(forEachSyntax,
constantValue: ConstantValue.Create(dimension, ConstantValueTypeDiscriminator.Int32),
type: intType));
// a.GetLowerBound(dimension)
BoundExpression currentDimensionLowerBound = BoundCall.Synthesized(forEachSyntax, boundArrayVar, getLowerBoundMethod, dimensionArgument);
// int p_dimension = a.GetLowerBound(dimension);
BoundStatement positionVarDecl = MakeLocalDeclaration(forEachSyntax, positionVar[dimension], currentDimensionLowerBound);
GeneratedLabelSymbol breakLabel = dimension == 0 // outermost for-loop
? node.BreakLabel // i.e. the one that break statements will jump to
: new GeneratedLabelSymbol("break"); // Should not affect emitted code since unused
// p_dimension <= q_dimension //NB: OrEqual
BoundExpression exitCondition = new BoundBinaryOperator(
syntax: forEachSyntax,
operatorKind: BinaryOperatorKind.IntLessThanOrEqual,
left: boundPositionVar[dimension],
right: boundUpperVar[dimension],
constantValueOpt: null,
methodOpt: null,
resultKind: LookupResultKind.Viable,
type: boolType);
// p_dimension = p_dimension + 1;
BoundStatement positionIncrement = MakePositionIncrement(forEachSyntax, boundPositionVar[dimension], intType);
BoundStatement body;
GeneratedLabelSymbol continueLabel;
if (forLoop == null)
{
// innermost for-loop
body = innermostLoopBody;
continueLabel = node.ContinueLabel; //i.e. the one continue statements will actually jump to
}
else
{
body = forLoop;
continueLabel = new GeneratedLabelSymbol("continue"); // Should not affect emitted code since unused
}
forLoop = RewriteForStatement(
syntax: forEachSyntax,
outerLocals: ImmutableArray.Create(positionVar[dimension]),
rewrittenInitializer: positionVarDecl,
rewrittenCondition: exitCondition,
conditionSyntaxOpt: null,
conditionSpanOpt: forEachSyntax.InKeyword.Span,
rewrittenIncrement: positionIncrement,
rewrittenBody: body,
breakLabel: breakLabel,
continueLabel: continueLabel,
hasErrors: node.HasErrors);
}
Debug.Assert(forLoop != null);
BoundStatement result = new BoundBlock(
forEachSyntax,
ImmutableArray.Create(arrayVar).Concat(upperVar.AsImmutableOrNull()),
ImmutableArray<LocalFunctionSymbol>.Empty,
ImmutableArray.Create(arrayVarDecl).Concat(upperVarDecl.AsImmutableOrNull()).Add(forLoop));
AddForEachKeywordSequencePoint(forEachSyntax, ref result);
return result;
}