/
SonarExplodedGraph.cs
1382 lines (1150 loc) · 65.2 KB
/
SonarExplodedGraph.cs
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/*
* SonarAnalyzer for .NET
* Copyright (C) 2015-2023 SonarSource SA
* mailto: contact AT sonarsource DOT com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
using SonarAnalyzer.CFG.Sonar;
using SonarAnalyzer.LiveVariableAnalysis.CSharp;
using SonarAnalyzer.SymbolicExecution.Constraints;
using SonarAnalyzer.SymbolicExecution.Sonar.Analyzers;
using SonarAnalyzer.SymbolicExecution.Sonar.Constraints;
using SonarAnalyzer.SymbolicExecution.Sonar.SymbolicValues;
namespace SonarAnalyzer.SymbolicExecution.Sonar
{
internal class SonarExplodedGraph : AbstractExplodedGraph
{
private const string isNullOrEmpty = "IsNullOrEmpty";
private const string isNullOrWhiteSpace = "IsNullOrWhiteSpace";
public SonarExplodedGraph(IControlFlowGraph cfg, ISymbol declaration, SemanticModel semanticModel, SonarCSharpLiveVariableAnalysis lva)
: base(cfg, declaration, semanticModel, lva)
{
NullPointerCheck = new NullPointerDereference.NullPointerCheck(this);
NullableValueAccessedCheck = new EmptyNullableValueAccess.NullableValueAccessedCheck(this);
// Add mandatory checks
AddExplodedGraphCheck(NullPointerCheck);
AddExplodedGraphCheck(NullableValueAccessedCheck);
AddExplodedGraphCheck(new InvalidCastToInterfaceSymbolicExecution.NullableCastCheck(this));
}
/// <summary>
/// NullPointerCheck is added by default by the SonarExplodedGraph to allow an early stop of the visit
/// when a null pointer dereference is found.
///
/// In order to be able to run all the rules within one single symbolic execution pass, we have to reuse,
/// instead of replace, this check in dependent analyzers (e.g. PublicMethodArgumentsShouldBeCheckedForNull
/// and NullPointerDereference).
/// </summary>
internal NullPointerDereference.NullPointerCheck NullPointerCheck { get; }
internal EmptyNullableValueAccess.NullableValueAccessedCheck NullableValueAccessedCheck { get; }
protected override void VisitSimpleBlock(SimpleBlock block, ExplodedGraphNode node)
{
var newProgramState = node.ProgramState;
if (block is UsingEndBlock)
{
newProgramState = InvokeChecks(newProgramState, (ps, check) => check.PreProcessUsingStatement(node.ProgramPoint, ps));
newProgramState = CleanStateAfterBlock(newProgramState, block);
EnqueueAllSuccessors(block, newProgramState);
return;
}
newProgramState = CleanStateAfterBlock(newProgramState, block);
if (block is ForeachCollectionProducerBlock)
{
newProgramState = newProgramState.PopValue();
EnqueueAllSuccessors(block, newProgramState);
return;
}
if (block is ForInitializerBlock forInitializerBlock)
{
newProgramState = newProgramState.PopValues(
forInitializerBlock.ForNode.Initializers.Count);
newProgramState = newProgramState.PushValues(
Enumerable
.Range(0, forInitializerBlock.ForNode.Incrementors.Count)
.Select(i => new SymbolicValue()));
EnqueueAllSuccessors(forInitializerBlock, newProgramState);
return;
}
if (block is LockBlock)
{
newProgramState = newProgramState.PopValue();
newProgramState = newProgramState.RemoveSymbols(IsFieldSymbol);
EnqueueAllSuccessors(block, newProgramState);
return;
}
base.VisitSimpleBlock(block, node);
}
protected override void VisitBinaryBranch(BinaryBranchBlock binaryBranchBlock, ExplodedGraphNode node)
{
var newProgramState = CleanStateAfterBlock(node.ProgramState, node.ProgramPoint.Block);
switch (binaryBranchBlock.BranchingNode.Kind())
{
case SyntaxKind.ForEachStatement:
VisitForeachBinaryBranch(binaryBranchBlock, newProgramState);
return;
case SyntaxKind.CoalesceExpression:
case SyntaxKindEx.CoalesceAssignmentExpression:
VisitCoalesceExpressionBinaryBranch(binaryBranchBlock, newProgramState);
return;
case SyntaxKind.ConditionalAccessExpression:
VisitConditionalAccessBinaryBranch(binaryBranchBlock, newProgramState);
return;
case SyntaxKind.LogicalAndExpression:
case SyntaxKind.LogicalOrExpression:
VisitBinaryBranch(binaryBranchBlock, node, ((BinaryExpressionSyntax)binaryBranchBlock.BranchingNode).Left);
return;
case SyntaxKind.ForStatement:
VisitBinaryBranch(binaryBranchBlock, node, ((ForStatementSyntax)binaryBranchBlock.BranchingNode).Condition);
return;
case SyntaxKind.ConditionalExpression:
VisitBinaryBranch(binaryBranchBlock, node, ((ConditionalExpressionSyntax)binaryBranchBlock.BranchingNode).Condition);
return;
case SyntaxKind.CatchFilterClause:
VisitBinaryBranch(binaryBranchBlock, node, ((CatchFilterClauseSyntax)binaryBranchBlock.BranchingNode).FilterExpression);
return;
// this is only for switch cases without a when. We handle C#7 switch case as a default BinaryBranch
case SyntaxKind.CaseSwitchLabel when !CasePatternSwitchLabelSyntaxWrapper.IsInstance(binaryBranchBlock.BranchingNode):
VisitCaseSwitchBinaryBranchBlock(binaryBranchBlock, node, (CaseSwitchLabelSyntax)binaryBranchBlock.BranchingNode);
return;
case SyntaxKindEx.SwitchExpressionArm:
VisitSwitchExpressionArmBinaryBranch(binaryBranchBlock, node, (SwitchExpressionArmSyntaxWrapper)binaryBranchBlock.BranchingNode);
return;
default:
VisitBinaryBranch(binaryBranchBlock, node, binaryBranchBlock.BranchingNode);
return;
}
}
protected override void VisitInstruction(ExplodedGraphNode node)
{
var instruction = node.ProgramPoint.CurrentInstruction;
var expression = instruction as ExpressionSyntax;
var parenthesizedExpression = expression?.GetSelfOrTopParenthesizedExpression();
var newProgramPoint = new ProgramPoint(node.ProgramPoint.Block, node.ProgramPoint.Offset + 1);
var newProgramState = node.ProgramState;
newProgramState = InvokeChecks(newProgramState, (ps, check) => check.PreProcessInstruction(node.ProgramPoint, ps));
if (newProgramState == null)
{
return;
}
switch (instruction.Kind())
{
case SyntaxKind.VariableDeclarator:
newProgramState = VisitVariableDeclarator((VariableDeclaratorSyntax)instruction, newProgramState);
break;
case SyntaxKind.SimpleAssignmentExpression:
case SyntaxKindEx.CoalesceAssignmentExpression:
newProgramState = VisitSimpleAssignment((AssignmentExpressionSyntax)instruction, newProgramState);
break;
case SyntaxKind.OrAssignmentExpression:
newProgramState = VisitBooleanBinaryOpAssignment(newProgramState, (AssignmentExpressionSyntax)instruction, (l, r) => new OrSymbolicValue(l, r));
break;
case SyntaxKind.AndAssignmentExpression:
newProgramState = VisitBooleanBinaryOpAssignment(newProgramState, (AssignmentExpressionSyntax)instruction, (l, r) => new AndSymbolicValue(l, r));
break;
case SyntaxKind.ExclusiveOrAssignmentExpression:
newProgramState = VisitBooleanBinaryOpAssignment(newProgramState, (AssignmentExpressionSyntax)instruction, (l, r) => new XorSymbolicValue(l, r));
break;
case SyntaxKind.SubtractAssignmentExpression:
case SyntaxKind.AddAssignmentExpression:
case SyntaxKind.DivideAssignmentExpression:
case SyntaxKind.MultiplyAssignmentExpression:
case SyntaxKind.ModuloAssignmentExpression:
case SyntaxKind.LeftShiftAssignmentExpression:
case SyntaxKind.RightShiftAssignmentExpression:
newProgramState = VisitOpAssignment((AssignmentExpressionSyntax)instruction, newProgramState);
break;
case SyntaxKind.PreIncrementExpression:
case SyntaxKind.PreDecrementExpression:
newProgramState = VisitPrefixIncrement((PrefixUnaryExpressionSyntax)instruction, newProgramState);
break;
case SyntaxKind.PostIncrementExpression:
case SyntaxKind.PostDecrementExpression:
newProgramState = VisitPostfixIncrement((PostfixUnaryExpressionSyntax)instruction, newProgramState);
break;
case SyntaxKind.IdentifierName:
newProgramState = VisitIdentifier((IdentifierNameSyntax)instruction, newProgramState);
break;
case SyntaxKind.BitwiseOrExpression:
newProgramState = VisitBinaryOperator(newProgramState, (l, r) => new OrSymbolicValue(l, r));
break;
case SyntaxKind.BitwiseAndExpression:
newProgramState = VisitBinaryOperator(newProgramState, (l, r) => new AndSymbolicValue(l, r));
break;
case SyntaxKind.ExclusiveOrExpression:
newProgramState = VisitBinaryOperator(newProgramState, (l, r) => new XorSymbolicValue(l, r));
break;
case SyntaxKind.LessThanExpression:
newProgramState = VisitComparisonBinaryOperator(newProgramState, instruction, (l, r) => new ComparisonSymbolicValue(SymbolicComparisonKind.Less, l, r));
break;
case SyntaxKind.LessThanOrEqualExpression:
newProgramState = VisitComparisonBinaryOperator(newProgramState, instruction, (l, r) => new ComparisonSymbolicValue(SymbolicComparisonKind.LessOrEqual, l, r));
break;
case SyntaxKind.GreaterThanExpression:
newProgramState = VisitComparisonBinaryOperator(newProgramState, instruction, (l, r) => new ComparisonSymbolicValue(SymbolicComparisonKind.Less, r, l));
break;
case SyntaxKind.GreaterThanOrEqualExpression:
newProgramState = VisitComparisonBinaryOperator(newProgramState, instruction, (l, r) => new ComparisonSymbolicValue(SymbolicComparisonKind.LessOrEqual, r, l));
break;
case SyntaxKind.SubtractExpression:
case SyntaxKind.AddExpression:
case SyntaxKind.DivideExpression:
case SyntaxKind.MultiplyExpression:
case SyntaxKind.ModuloExpression:
case SyntaxKind.LeftShiftExpression:
case SyntaxKind.RightShiftExpression:
newProgramState = newProgramState.PopValues(2);
newProgramState = newProgramState.PushValue(new SymbolicValue());
break;
case SyntaxKind.EqualsExpression:
var binary = (BinaryExpressionSyntax)instruction;
newProgramState = IsOperatorOnObject(instruction)
? VisitReferenceEquals(binary, newProgramState)
: VisitValueEquals(newProgramState);
break;
case SyntaxKind.NotEqualsExpression:
newProgramState = IsOperatorOnObject(instruction)
? VisitBinaryOperator(newProgramState, (l, r) => new ReferenceNotEqualsSymbolicValue(l, r))
: VisitBinaryOperator(newProgramState, (l, r) => new ValueNotEqualsSymbolicValue(l, r));
break;
case SyntaxKind.BitwiseNotExpression:
case SyntaxKind.UnaryMinusExpression:
case SyntaxKind.UnaryPlusExpression:
case SyntaxKind.AddressOfExpression:
case SyntaxKind.PointerIndirectionExpression:
case SyntaxKind.MakeRefExpression:
case SyntaxKind.RefTypeExpression:
case SyntaxKind.RefValueExpression:
case SyntaxKind.MemberBindingExpression:
newProgramState = newProgramState.PopValue();
newProgramState = newProgramState.PushValue(new SymbolicValue());
break;
case SyntaxKind.AwaitExpression:
newProgramState = newProgramState.RemoveSymbols(IsFieldSymbol);
newProgramState = newProgramState.PopValue();
newProgramState = newProgramState.PushValue(new SymbolicValue());
break;
case SyntaxKind.AsExpression:
case SyntaxKind.IsExpression:
newProgramState = VisitSafeCastExpression((BinaryExpressionSyntax)instruction, newProgramState);
break;
case SyntaxKind.SimpleMemberAccessExpression:
{
var memberAccess = (MemberAccessExpressionSyntax)instruction;
var check = this.explodedGraphChecks.OfType<EmptyNullableValueAccess.NullableValueAccessedCheck>().FirstOrDefault();
if (check == null || !check.TryProcessInstruction(memberAccess, newProgramState, out newProgramState))
{
// Default behavior
newProgramState = VisitMemberAccess(memberAccess, newProgramState);
}
}
break;
case SyntaxKind.PointerMemberAccessExpression:
{
newProgramState = VisitMemberAccess((MemberAccessExpressionSyntax)instruction, newProgramState);
}
break;
case SyntaxKind.GenericName:
case SyntaxKind.AliasQualifiedName:
case SyntaxKind.QualifiedName:
case SyntaxKind.PredefinedType:
case SyntaxKind.NullableType:
case SyntaxKind.OmittedArraySizeExpression:
case SyntaxKind.AnonymousMethodExpression:
case SyntaxKind.ParenthesizedLambdaExpression:
case SyntaxKind.SimpleLambdaExpression:
case SyntaxKind.QueryExpression:
case SyntaxKind.ArgListExpression:
newProgramState = newProgramState.PushValue(new SymbolicValue());
break;
case SyntaxKind.LogicalNotExpression:
{
newProgramState = newProgramState.PopValue(out var sv);
newProgramState = newProgramState.PushValue(new LogicalNotSymbolicValue(sv));
}
break;
case SyntaxKind.TrueLiteralExpression:
newProgramState = newProgramState.PushValue(SymbolicValue.True);
break;
case SyntaxKind.FalseLiteralExpression:
newProgramState = newProgramState.PushValue(SymbolicValue.False);
break;
case SyntaxKind.NullLiteralExpression:
newProgramState = newProgramState.PushValue(SymbolicValue.Null);
break;
case SyntaxKind.ThisExpression:
newProgramState = newProgramState.PushValue(SymbolicValue.This);
break;
case SyntaxKind.BaseExpression:
newProgramState = newProgramState.PushValue(SymbolicValue.Base);
break;
case SyntaxKind.StringLiteralExpression:
{
var stringLiteralExpression = instruction as LiteralExpressionSyntax;
var sv = new SymbolicValue();
var valueText = stringLiteralExpression.Token.ValueText;
if (string.IsNullOrEmpty(valueText))
{
newProgramState = newProgramState.SetConstraint(sv, StringConstraint.EmptyString);
}
else if (string.IsNullOrWhiteSpace(valueText))
{
newProgramState = newProgramState.SetConstraint(sv, StringConstraint.WhiteSpaceString);
}
else
{
newProgramState = newProgramState.SetConstraint(sv, StringConstraint.FullNotWhiteSpaceString);
}
newProgramState = newProgramState.SetConstraint(sv, ObjectConstraint.NotNull);
newProgramState = newProgramState.PushValue(sv);
newProgramState = InvokeChecks(newProgramState,
(ps, check) => check.ObjectCreated(ps, sv, instruction));
}
break;
case SyntaxKind.CharacterLiteralExpression:
case SyntaxKind.NumericLiteralExpression:
case SyntaxKind.SizeOfExpression:
case SyntaxKind.TypeOfExpression:
case SyntaxKind.ArrayCreationExpression:
case SyntaxKind.ImplicitArrayCreationExpression:
case SyntaxKind.StackAllocArrayCreationExpression:
case SyntaxKindEx.RangeExpression:
case SyntaxKindEx.IndexExpression:
{
var sv = new SymbolicValue();
newProgramState = newProgramState.SetConstraint(sv, ObjectConstraint.NotNull);
newProgramState = newProgramState.PushValue(sv);
newProgramState = InvokeChecks(newProgramState,
(ps, check) => check.ObjectCreated(ps, sv, instruction));
}
break;
case SyntaxKind.DefaultExpression:
case SyntaxKindEx.DefaultLiteralExpression:
newProgramState = VisitDefaultExpression(instruction, newProgramState);
break;
case SyntaxKind.AnonymousObjectCreationExpression:
{
var creation = (AnonymousObjectCreationExpressionSyntax)instruction;
newProgramState = newProgramState.PopValues(creation.Initializers.Count);
var sv = new SymbolicValue();
newProgramState = newProgramState.SetConstraint(sv, ObjectConstraint.NotNull);
newProgramState = newProgramState.PushValue(sv);
newProgramState = InvokeChecks(newProgramState,
(ps, check) => check.ObjectCreated(ps, sv, instruction));
}
break;
case SyntaxKind.CastExpression:
case SyntaxKind.CheckedExpression:
case SyntaxKind.UncheckedExpression:
// Do nothing
break;
case SyntaxKind.InterpolatedStringExpression:
newProgramState = newProgramState.PopValues(((InterpolatedStringExpressionSyntax)instruction).Contents.OfType<InterpolationSyntax>().Count());
newProgramState = newProgramState.PushValue(new SymbolicValue());
break;
case SyntaxKind.ObjectCreationExpression:
newProgramState = VisitObjectCreation((ObjectCreationExpressionSyntax)instruction, newProgramState);
break;
case SyntaxKind.ElementAccessExpression:
newProgramState = newProgramState.PopValues((((ElementAccessExpressionSyntax)instruction).ArgumentList?.Arguments.Count ?? 0) + 1);
newProgramState = newProgramState.PushValue(new SymbolicValue());
break;
case SyntaxKind.ImplicitElementAccess:
newProgramState = newProgramState
.PopValues(((ImplicitElementAccessSyntax)instruction).ArgumentList?.Arguments.Count ?? 0)
.PushValue(new SymbolicValue());
break;
case SyntaxKind.ObjectInitializerExpression:
case SyntaxKind.ArrayInitializerExpression:
case SyntaxKind.CollectionInitializerExpression:
case SyntaxKind.ComplexElementInitializerExpression:
newProgramState = VisitInitializer(instruction, parenthesizedExpression, newProgramState);
break;
case SyntaxKind.ArrayType:
newProgramState = newProgramState.PopValues(((ArrayTypeSyntax)instruction).RankSpecifiers.SelectMany(rs => rs.Sizes).Count());
break;
case SyntaxKind.ElementBindingExpression:
newProgramState = newProgramState.PopValues(((ElementBindingExpressionSyntax)instruction).ArgumentList?.Arguments.Count ?? 0);
newProgramState = newProgramState.PushValue(new SymbolicValue());
break;
case SyntaxKind.InvocationExpression:
{
var invocation = (InvocationExpressionSyntax)instruction;
var invocationVisitor = new InvocationVisitor(invocation, SemanticModel, newProgramState);
newProgramState = invocationVisitor.ProcessInvocation();
if (!invocation.IsNameof(SemanticModel))
{
newProgramState = newProgramState.RemoveSymbols(IsFieldSymbol);
}
}
break;
case SyntaxKind.BaseConstructorInitializer:
case SyntaxKind.ThisConstructorInitializer:
var constructorInitializer = (ConstructorInitializerSyntax)instruction;
if (constructorInitializer.ArgumentList != null)
{
var ctorInitializerArgumentsCount = constructorInitializer.ArgumentList.Arguments.Count;
newProgramState = newProgramState.PopValues(ctorInitializerArgumentsCount);
}
break;
case SyntaxKindEx.IsPatternExpression:
// condition with pattern (if, do, while, for, etc.) "if (x is string s)" or "if (x is null)"
var isPatternExpression = (IsPatternExpressionSyntaxWrapper)instruction;
if (ConstantPatternSyntaxWrapper.IsInstance(isPatternExpression.Pattern))
{
// "x is null" is equivalent to "x == null"
newProgramState = VisitValueEquals(newProgramState);
}
else if (DeclarationPatternSyntaxWrapper.IsInstance(isPatternExpression.Pattern))
{
// "x is string s"
// VisitDeclarationPattern() expects SV_s on top of the stack, hence we pop SV_x
newProgramState = newProgramState.PopValue(out var SV_x);
// Check that current execution path is not compatible with previous null constraint
if (newProgramState.HasConstraint(SV_x, ObjectConstraint.Null))
{
return;
}
newProgramState = VisitDeclarationPattern((DeclarationPatternSyntaxWrapper)isPatternExpression.Pattern, newProgramState);
}
else if (RecursivePatternSyntaxWrapper.IsInstance(isPatternExpression.Pattern))
{
newProgramState = VisitRecursivePattern((RecursivePatternSyntaxWrapper)isPatternExpression.Pattern, newProgramState);
}
else
{
throw new NotSupportedException($"{instruction.Kind()}");
}
break;
case SyntaxKindEx.DeclarationPattern:
// a pattern from a case section "string s"
newProgramState = VisitDeclarationPattern((DeclarationPatternSyntaxWrapper)instruction, newProgramState);
break;
case SyntaxKindEx.VarPattern:
newProgramState = VisitVarPattern((VarPatternSyntaxWrapper)instruction, newProgramState);
break;
case SyntaxKindEx.ConstantPattern:
// The 0 in 'case 0 when ...'
// Do nothing
break;
case SyntaxKindEx.RecursivePattern:
// Recursive pattern should be handled by IsPatternExpression and SwitchExpressionArm
// Do nothing.
break;
case SyntaxKindEx.DeclarationExpression:
newProgramState = VisitDeclarationExpression((DeclarationExpressionSyntaxWrapper)instruction, newProgramState);
break;
case SyntaxKindEx.TupleExpression:
newProgramState = VisitTuple((TupleExpressionSyntaxWrapper)instruction, newProgramState);
break;
case SyntaxKindEx.RefExpression:
// RefExpression is not yet supported: https://github.com/SonarSource/sonar-dotnet/issues/3024
// Do nothing
break;
case SyntaxKindEx.TypePattern:
// TypePattern is not yet supported: https://github.com/SonarSource/sonar-dotnet/issues/4104
// Do nothing
break;
case SyntaxKindEx.RelationalPattern:
// RelationalPattern is not yet supported: https://github.com/SonarSource/sonar-dotnet/issues/4104
// Do nothing
break;
case SyntaxKindEx.AndPattern:
// AndPattern is not yet supported: https://github.com/SonarSource/sonar-dotnet/issues/4880
// Do nothing
break;
case SyntaxKindEx.OrPattern:
// OrPattern is not yet supported: https://github.com/SonarSource/sonar-dotnet/issues/4880
// Do nothing
break;
case SyntaxKindEx.NotPattern:
// NotPattern is not yet supported: https://github.com/SonarSource/sonar-dotnet/issues/4880
// Do nothing
break;
default:
// Not Supported
// Do nothing
break;
}
newProgramState = InvokeChecks(newProgramState, (ps, check) => check.PostProcessInstruction(node.ProgramPoint, ps));
newProgramState = EnsureStackState(parenthesizedExpression, newProgramState);
OnInstructionProcessed(instruction, node.ProgramPoint, newProgramState);
EnqueueNewNode(newProgramPoint, newProgramState);
}
private static ProgramState VisitRecursivePattern(RecursivePatternSyntaxWrapper recursivePattern, ProgramState programState)
{
// Currently RecursivePatterns are not considered during the symbolic execution
// https://github.com/SonarSource/sonar-dotnet/issues/2937
return programState;
}
private ProgramState VisitDeclarationExpression(DeclarationExpressionSyntaxWrapper wrapper, ProgramState programState)
{
if (ParenthesizedVariableDesignationSyntaxWrapper.IsInstance(wrapper.Designation))
{
return VisitParenthesizedVariableDesignationSyntax((ParenthesizedVariableDesignationSyntaxWrapper)wrapper.Designation, programState);
}
if (DiscardDesignationSyntaxWrapper.IsInstance(wrapper.Designation))
{
return VisitDiscardDesignationSyntax(programState);
}
var declaredSymbol = SemanticModel.GetDeclaredSymbol(wrapper.Designation);
var symbolicValue = SymbolicValue.Create(declaredSymbol.GetSymbolType());
programState = SetNonNullConstraintIfValueType(declaredSymbol, symbolicValue, programState);
programState = programState.PushValue(symbolicValue);
programState = programState.StoreSymbolicValue(declaredSymbol, symbolicValue);
return programState;
}
private static ProgramState VisitDiscardDesignationSyntax(ProgramState programState)
{
// In case of discard designation we push a new symbolic value with no constraints.
// This is used when processing method invocations since, when the method is called, we pop a symbolic value
// from the expression stack for each method argument.
programState = programState.PushValue(new SymbolicValue());
return programState;
}
private ProgramState VisitParenthesizedVariableDesignationSyntax(ParenthesizedVariableDesignationSyntaxWrapper designation, ProgramState programState)
{
foreach (var variable in designation.Variables)
{
// No symbolic values are created and pushed to the stack since they are not currently used.
// See also VisitSimpleAssignment where ParenthesizedVariableDesignationSyntaxWrapper are handled.
programState = variable.SyntaxNode.Kind() switch
{
SyntaxKindEx.SingleVariableDesignation => SetSymbolValue(SemanticModel.GetDeclaredSymbol(variable)),
SyntaxKindEx.ParenthesizedVariableDesignation => VisitParenthesizedVariableDesignationSyntax((ParenthesizedVariableDesignationSyntaxWrapper)variable, programState),
_ => programState // DiscardDesignation
};
}
return programState;
ProgramState SetSymbolValue(ISymbol variableSymbol) =>
programState.StoreSymbolicValue(variableSymbol, SymbolicValue.Create(variableSymbol.GetSymbolType()));
}
private ProgramState VisitVarPattern(VarPatternSyntaxWrapper varPatternSyntax, ProgramState programState) =>
// "var x" in "case var x when ..."
//
// VarPattern is treated the same as DeclarationPattern since both have a very similar structure:
//
// VarPattern DeclarationPattern
// - VarKeyword - PredefinedType
// - SingleVariableDesignation - SingleVariableDesignation
// - IdentifierToken - IdentifierToken
VisitVariableDesignation(varPatternSyntax.Designation, programState);
private ProgramState VisitDeclarationPattern(DeclarationPatternSyntaxWrapper declarationPattern, ProgramState newProgramState) =>
// "x is string s" is equivalent to "s = x" and "s" gets NotNull constraint
// "x is (string s, int i)" is recursive pattern with PositionalPatternClause and doesn't reach this path
VisitVariableDesignation(declarationPattern.Designation, newProgramState);
/// <param name="isInParanthesizedVariableDesignation">True for variables nested in ParenthesizedVariableDesignationSyntax "var (string s, int i)".</param>
private ProgramState VisitVariableDesignation(VariableDesignationSyntaxWrapper variableDesignation, ProgramState programState, bool isInParanthesizedVariableDesignation = false)
{
var newProgramState = programState;
if (DiscardDesignationSyntaxWrapper.IsInstance(variableDesignation))
{
// Push value for the discard, it will be popped when visiting the block for the corresponding case statement.
newProgramState = newProgramState.PushValue(new SymbolicValue());
}
else if (SingleVariableDesignationSyntaxWrapper.IsInstance(variableDesignation))
{
// "x is string s" is equivalent to "s = x"; both symbolic values should remain on stack
var singleVariableDesignation = (SingleVariableDesignationSyntaxWrapper)variableDesignation;
// associate variable with new SV
var variableSymbol = SemanticModel.GetDeclaredSymbol(singleVariableDesignation);
var newSymbolicValue = SymbolicValue.Create();
newProgramState = SetNewSymbolicValueIfTracked(variableSymbol, newSymbolicValue, newProgramState);
if (!isInParanthesizedVariableDesignation)
{
// When the pattern is "x is Type t" we know that "t != null", hence (SV != null)
newProgramState = newProgramState.SetConstraint(newSymbolicValue, ObjectConstraint.NotNull);
newProgramState = newProgramState.PushValue(new SymbolicValue());
}
}
else if (ParenthesizedVariableDesignationSyntaxWrapper.IsInstance(variableDesignation))
{
var parenthesizedVariableDesignation = (ParenthesizedVariableDesignationSyntaxWrapper)variableDesignation;
foreach (var variable in parenthesizedVariableDesignation.Variables)
{
// the variables in the deconstruction should not receive "Not Null" constraint
newProgramState = VisitVariableDesignation(variable, newProgramState, true);
}
// Push value for the result of "var (string s, int i) when ....", it will be popped when visiting the block for the corresponding case statement.
newProgramState = newProgramState.PushValue(new SymbolicValue());
}
else
{
throw new NotSupportedException($"{variableDesignation.SyntaxNode.Kind()}");
}
return newProgramState;
}
// If a check returns null, we will skip the next checks and return null
private ProgramState InvokeChecks(ProgramState programState, Func<ProgramState, ExplodedGraphCheck, ProgramState> invoke) =>
explodedGraphChecks.Aggregate(programState, (ps, check) => ps == null ? null : invoke(ps, check));
private ProgramState EnsureStackState(ExpressionSyntax parenthesizedExpression, ProgramState programState)
{
if (ShouldConsumeValue(parenthesizedExpression))
{
var newProgramState = programState.PopValue();
System.Diagnostics.Debug.Assert(!newProgramState.HasValue);
return newProgramState;
}
return programState;
}
#region Handle VisitBinaryBranch cases
private void VisitForeachBinaryBranch(BinaryBranchBlock binaryBranchBlock, ProgramState programState)
{
// foreach variable is not a VariableDeclarator, so we need to assign a value to it
var foreachVariableSymbol = SemanticModel.GetDeclaredSymbol(binaryBranchBlock.BranchingNode);
var sv = new SymbolicValue();
var newProgramState = SetNonNullConstraintIfValueType(foreachVariableSymbol, sv, programState);
newProgramState = SetNewSymbolicValueIfTracked(foreachVariableSymbol, sv, newProgramState);
EnqueueAllSuccessors(binaryBranchBlock, newProgramState);
}
private void VisitCoalesceExpressionBinaryBranch(BinaryBranchBlock binaryBranchBlock, ProgramState programState)
{
var ps = programState.PopValue(out var sv);
foreach (var newProgramState in sv.TrySetConstraint(ObjectConstraint.Null, ps))
{
EnqueueNewNode(new ProgramPoint(binaryBranchBlock.TrueSuccessorBlock), newProgramState);
}
foreach (var newProgramState in sv.TrySetOppositeConstraint(ObjectConstraint.Null, ps))
{
var nps = newProgramState;
if (!ShouldConsumeValue((ExpressionSyntax)binaryBranchBlock.BranchingNode)
|| binaryBranchBlock.BranchingNode?.Kind() == SyntaxKindEx.CoalesceAssignmentExpression)
{
nps = nps.PushValue(sv);
}
EnqueueNewNode(new ProgramPoint(binaryBranchBlock.FalseSuccessorBlock), nps);
}
}
private void VisitConditionalAccessBinaryBranch(BinaryBranchBlock binaryBranchBlock, ProgramState programState)
{
if (!programState.HasValue)
{
return;
}
var ps = programState.PopValue(out var sv);
foreach (var newProgramState in sv.TrySetConstraint(ObjectConstraint.Null, ps))
{
var nps = newProgramState;
if (!ShouldConsumeValue((ConditionalAccessExpressionSyntax)binaryBranchBlock.BranchingNode))
{
nps = nps.PushValue(SymbolicValue.Null);
}
EnqueueNewNode(new ProgramPoint(binaryBranchBlock.TrueSuccessorBlock), nps);
}
foreach (var newProgramState in sv.TrySetOppositeConstraint(ObjectConstraint.Null, ps))
{
EnqueueNewNode(new ProgramPoint(binaryBranchBlock.FalseSuccessorBlock), newProgramState);
}
}
private void VisitCaseSwitchBinaryBranchBlock(BinaryBranchBlock branchBlock, ExplodedGraphNode node, CaseSwitchLabelSyntax simpleCaseLabel)
{
var programState = CleanStateAfterBlock(node.ProgramState, node.ProgramPoint.Block);
var ps = programState.PopValue(out var sv);
if (simpleCaseLabel.Value.IsNullLiteral())
{
foreach (var newProgramState in sv.TrySetConstraint(ObjectConstraint.Null, ps))
{
EnqueueNewNode(new ProgramPoint(branchBlock.TrueSuccessorBlock), newProgramState);
}
foreach (var newProgramState in sv.TrySetOppositeConstraint(ObjectConstraint.Null, ps))
{
EnqueueNewNode(new ProgramPoint(branchBlock.FalseSuccessorBlock), newProgramState);
}
}
else
{
foreach (var newProgramState in sv.TrySetOppositeConstraint(ObjectConstraint.Null, ps))
{
EnqueueNewNode(new ProgramPoint(branchBlock.TrueSuccessorBlock), newProgramState);
}
// False succesor is the next case block. It is always enqueued without constraint
EnqueueNewNode(new ProgramPoint(branchBlock.FalseSuccessorBlock), ps);
}
}
private void VisitSwitchExpressionArmBinaryBranch(BinaryBranchBlock branchBlock, ExplodedGraphNode node, SwitchExpressionArmSyntaxWrapper armSyntaxWrapper)
{
var programState = node.ProgramState;
SymbolicValue armPatternSymbolicValue = null;
// Constant pattern is the only one appearing as instruction, so we need to pop its value from the stack
if (ConstantPatternSyntaxWrapper.IsInstance(armSyntaxWrapper.Pattern))
{
programState = programState.PopValue(out armPatternSymbolicValue);
}
if (RecursivePatternSyntaxWrapper.IsInstance(armSyntaxWrapper.Pattern))
{
programState = VisitRecursivePattern((RecursivePatternSyntaxWrapper)armSyntaxWrapper.Pattern, programState);
}
programState = programState.PopValue(out var governingExpression);
if (armPatternSymbolicValue != null && armPatternSymbolicValue.IsNull(programState))
{
foreach (var newProgramState in governingExpression.TrySetConstraint(ObjectConstraint.Null, programState))
{
EnqueueNewNode(new ProgramPoint(branchBlock.TrueSuccessorBlock), newProgramState);
}
foreach (var newProgramState in governingExpression.TrySetOppositeConstraint(ObjectConstraint.Null, programState))
{
EnqueueNewNode(new ProgramPoint(branchBlock.FalseSuccessorBlock), newProgramState);
}
}
else
{
EnqueueNewNode(new ProgramPoint(branchBlock.TrueSuccessorBlock), programState);
EnqueueNewNode(new ProgramPoint(branchBlock.FalseSuccessorBlock), programState);
}
}
private void VisitBinaryBranch(BinaryBranchBlock binaryBranchBlock, ExplodedGraphNode node, SyntaxNode instruction)
{
var ps = node.ProgramState;
if (!ps.HasValue)
{
return;
}
SymbolicValue sv;
if (binaryBranchBlock.BranchingNode is ForStatementSyntax forStatement)
{
if (forStatement.Condition == null)
{
ps = ps.PushValue(SymbolicValue.True);
}
ps = ps.PopValue(out sv);
ps = ps.PopValues(forStatement.Incrementors.Count);
}
else
{
ps = ps.PopValue(out sv);
}
foreach (var newProgramState in sv.TrySetConstraint(BoolConstraint.True, ps))
{
OnConditionEvaluated(instruction, evaluationValue: true);
// this inner loop is to give the possibility of handling the same block with different constraints/programstate.
foreach (var innerNewProgramState in GenerateNewProgramTrueState(binaryBranchBlock, sv, newProgramState))
{
EnqueueNewNode(new ProgramPoint(binaryBranchBlock.TrueSuccessorBlock), CleanStateAfterBlock(innerNewProgramState, node.ProgramPoint.Block));
}
}
foreach (var newProgramState in sv.TrySetOppositeConstraint(BoolConstraint.True, ps))
{
OnConditionEvaluated(instruction, evaluationValue: false);
foreach (var innerNewProgramState in GenerateNewProgramFalseState(binaryBranchBlock, sv, newProgramState))
{
EnqueueNewNode(new ProgramPoint(binaryBranchBlock.FalseSuccessorBlock), CleanStateAfterBlock(innerNewProgramState, node.ProgramPoint.Block));
}
}
}
private static IEnumerable<ProgramState> GenerateNewProgramFalseState(BinaryBranchBlock binaryBranchBlock, SymbolicValue sv, ProgramState newProgramState)
{
var nps = binaryBranchBlock.BranchingNode.IsKind(SyntaxKind.LogicalAndExpression)
? newProgramState.PushValue(SymbolicValue.False)
: newProgramState;
if (sv is ReferenceEqualsSymbolicValue referenceEqualsSymbolicValue
&& referenceEqualsSymbolicValue.RightOperand is MemberAccessSymbolicValue rightOperand)
{
if (rightOperand.MemberName == isNullOrEmpty)
{
return referenceEqualsSymbolicValue.LeftOperand.TrySetConstraint(StringConstraint.FullString, nps);
}
if (rightOperand.MemberName == isNullOrWhiteSpace)
{
return referenceEqualsSymbolicValue.LeftOperand.TrySetConstraint(StringConstraint.FullNotWhiteSpaceString, nps);
}
}
if (sv is LogicalNotSymbolicValue logicalNotSymbolicValue
&& logicalNotSymbolicValue.Operand is ReferenceEqualsSymbolicValue logicalNotReferenceEqualsSymbolicValue
&& logicalNotReferenceEqualsSymbolicValue.RightOperand is MemberAccessSymbolicValue logicalNotRightOperand)
{
if (logicalNotRightOperand.MemberName == isNullOrEmpty)
{
return NullOrEmptyStringStates(nps, logicalNotReferenceEqualsSymbolicValue);
}
if (logicalNotRightOperand.MemberName == isNullOrWhiteSpace)
{
return NullOrEmptyOrWhiteSpaceStringStates(nps, logicalNotReferenceEqualsSymbolicValue);
}
}
return new[] { nps };
}
private static IEnumerable<ProgramState> GenerateNewProgramTrueState(BinaryBranchBlock binaryBranchBlock, SymbolicValue sv, ProgramState newProgramState)
{
var nps = binaryBranchBlock.BranchingNode.IsKind(SyntaxKind.LogicalOrExpression)
? newProgramState.PushValue(SymbolicValue.True)
: newProgramState;
if (sv is ReferenceEqualsSymbolicValue referenceEqualsSymbolicValue
&& referenceEqualsSymbolicValue.RightOperand is MemberAccessSymbolicValue rightOperand)
{
if (rightOperand.MemberName == isNullOrEmpty)
{
return NullOrEmptyStringStates(nps, referenceEqualsSymbolicValue);
}
if (rightOperand.MemberName == isNullOrWhiteSpace)
{
return NullOrEmptyOrWhiteSpaceStringStates(nps, referenceEqualsSymbolicValue);
}
}
if (sv is LogicalNotSymbolicValue logicalNotSymbolicValue
&& logicalNotSymbolicValue.Operand is ReferenceEqualsSymbolicValue logicalNotReferenceEqualsSymbolicValue
&& logicalNotReferenceEqualsSymbolicValue.RightOperand is MemberAccessSymbolicValue logicalNotRightOperand)
{
if (logicalNotRightOperand.MemberName == isNullOrEmpty)
{
return logicalNotReferenceEqualsSymbolicValue.LeftOperand.TrySetConstraint(StringConstraint.FullString, nps);
}
if (logicalNotRightOperand.MemberName == isNullOrWhiteSpace)
{
return logicalNotReferenceEqualsSymbolicValue.LeftOperand.TrySetConstraint(StringConstraint.FullNotWhiteSpaceString, nps);
}
}
return new[] { nps };
}
private static IEnumerable<ProgramState> NullOrEmptyStringStates(ProgramState nps, ReferenceEqualsSymbolicValue referenceEqualsSymbolicValue)
{
var newProgramStateNull = referenceEqualsSymbolicValue.LeftOperand.TrySetConstraint(ObjectConstraint.Null, nps);
var newProgramStateEmpty = referenceEqualsSymbolicValue.LeftOperand.TrySetConstraint(StringConstraint.EmptyString, nps);
return newProgramStateNull.Concat(newProgramStateEmpty);
}
private static IEnumerable<ProgramState> NullOrEmptyOrWhiteSpaceStringStates(ProgramState nps, ReferenceEqualsSymbolicValue referenceEqualsSymbolicValue)
{
var newProgramStateNull = referenceEqualsSymbolicValue.LeftOperand.TrySetConstraint(ObjectConstraint.Null, nps);
var newProgramStateEmpty = referenceEqualsSymbolicValue.LeftOperand.TrySetConstraint(StringConstraint.EmptyString, nps);
var newProgramStateWhiteSpace = referenceEqualsSymbolicValue.LeftOperand.TrySetConstraint(StringConstraint.WhiteSpaceString, nps);
return newProgramStateNull.Concat(newProgramStateEmpty).Concat(newProgramStateWhiteSpace);
}
#endregion Handle VisitBinaryBranch cases
#region VisitExpression
private ProgramState VisitMemberAccess(MemberAccessExpressionSyntax memberAccess, ProgramState programState)
{
var newProgramState = programState.PopValue(out var memberExpression);
SymbolicValue sv = null;
if (memberAccess.Name is IdentifierNameSyntax identifier)
{
var symbol = SemanticModel.GetSymbolInfo(identifier).Symbol;
if (symbol is IFieldSymbol fieldSymbol && (memberAccess.IsOnThis() || fieldSymbol.IsConst))
{
sv = newProgramState.GetSymbolValue(symbol);
if (sv == null)
{
sv = CreateFieldSymbolicValue(fieldSymbol);
newProgramState = newProgramState.StoreSymbolicValue(symbol, sv);