/// <summary>
/// Accumulates all elements from <paramref name="sourceContract"/> into <paramref name="targetContract"/>
/// </summary>
/// <param name="targetContract">Contract which is target of accumulator</param>
/// <param name="sourceContract">Contract which is source of accumulator</param>
public static void AddMethodContract(MethodContract targetContract, IMethodContract sourceContract) {
targetContract.Locations.AddRange(sourceContract.Locations);
targetContract.Preconditions.AddRange(sourceContract.Preconditions);
targetContract.Postconditions.AddRange(sourceContract.Postconditions);
targetContract.ThrownExceptions.AddRange(sourceContract.ThrownExceptions);
targetContract.IsPure |= sourceContract.IsPure; // need the disjunction
return;
}
public override void TraverseChildren(IMethodDefinition method)
{
if (!MemberHelper.IsVisibleOutsideAssembly(method))
{
return;
}
var returnType = method.Type;
if (returnType == this.host.PlatformType.SystemVoid ||
returnType.IsEnum ||
returnType.IsValueType
)
{
return;
}
var newContract = new Microsoft.Cci.MutableContracts.MethodContract();
var post = new List <IPostcondition>();
var p = new Microsoft.Cci.MutableContracts.Postcondition()
{
Condition = new NotEquality()
{
LeftOperand = new ReturnValue()
{
Type = returnType,
},
RightOperand = new CompileTimeConstant()
{
Type = returnType,
Value = null,
},
Type = this.host.PlatformType.SystemBoolean,
},
OriginalSource = "result != null",
};
post.Add(p);
newContract.Postconditions = post;
var contract = this.contractProvider.GetMethodContractFor(method);
if (contract != null)
{
Microsoft.Cci.MutableContracts.ContractHelper.AddMethodContract(newContract, contract);
}
this.contractProvider.AssociateMethodWithContract(method, newContract);
base.TraverseChildren(method);
}
/// <summary>
/// Mutates the <paramref name="methodContract"/> by removing any contracts that violate any of the rules
/// about contracts, e.g., preconditions mentioning a member that is more restrictive than the method containing
/// the precondition.
/// TODO: Return a list of errors.
/// </summary>
public static void CheckMethodContract(IMetadataHost host, IMethodDefinition method, MethodContract methodContract) {
var reqs = methodContract.Preconditions;
var newReqs = new List<IPrecondition>(methodContract.Preconditions.Count);
foreach (var p in reqs) {
var contractExpression = p.Condition;
var v = Visibility.MostRestrictiveVisibility(host, contractExpression);
var currentVisibility = method.Visibility;
var intersection = TypeHelper.VisibilityIntersection(v, currentVisibility);
if (intersection == currentVisibility) {
newReqs.Add(p);
} else {
// TODO!! BUGBUG!! Need to signal an error, not just silently not add the precondition!
}
}
methodContract.Preconditions = newReqs;
}
public override void TraverseChildren(IMethodDefinition method)
{
// inject only in visible method
if(!MemberHelper.IsVisibleOutsideAssembly(method))
return;
// inject only in methods that return a reference type
var returnType = method.Type;
if(returnType == this.host.PlatformType.SystemVoid
|| returnType.IsValueType)
return;
// create new postcondition
// Contract.Ensures(Contract.Result<T>() != null);
var newContract = new MethodContract
{
Postconditions = new List<IPostcondition> {
new Postcondition {
// !=
Condition = new NotEquality {
// result
LeftOperand = new ReturnValue { Type = returnType, },
// null
RightOperand = new CompileTimeConstant {
Type = returnType,
Value = null,
},
Type = this.host.PlatformType.SystemBoolean,
},
// description
OriginalSource = "result != null",
}
}
};
// merge existing contracts, if any
var contract = this.contractProvider.GetMethodContractFor(method);
if(contract != null)
{
ContractHelper.AddMethodContract(newContract,contract);
}
// store new contracts
this.host.Event(CcsEventLevel.Message,"ensures not null: {0}",method);
this.contractProvider.AssociateMethodWithContract(method,newContract);
}
/// <summary>
/// Visits the specified method contract.
/// </summary>
/// <param name="methodContract">The method contract.</param>
/// <returns></returns>
protected virtual IMethodContract DeepCopy(MethodContract methodContract) {
methodContract.Allocates = this.DeepCopy(methodContract.Allocates);
methodContract.Frees = this.DeepCopy(methodContract.Frees);
methodContract.ModifiedVariables = this.DeepCopy(methodContract.ModifiedVariables);
methodContract.Postconditions = this.DeepCopy(methodContract.Postconditions);
methodContract.Preconditions = this.DeepCopy(methodContract.Preconditions);
methodContract.Reads = this.DeepCopy(methodContract.Reads);
methodContract.ThrownExceptions = this.DeepCopy(methodContract.ThrownExceptions);
methodContract.Writes = this.DeepCopy(methodContract.Writes);
return methodContract;
}
/// <summary>
/// Returns the method contract, if any, that has been associated with the given object. Returns null if no association exits.
/// </summary>
/// <param name="method">An object that might have been associated with a method contract. This can be any kind of object.</param>
/// <returns></returns>
/*?*/
public IMethodContract GetMethodContractFor(object method)
{
if (this.methodsBeingExtracted.Contains(method)) {
// hit a cycle while chasing validators/abbreviators
// TODO: signal error
return null;
} else {
this.methodsBeingExtracted.Add(method);
}
try {
IMethodContract contract = this.underlyingContractProvider.GetMethodContractFor(method);
if (contract != null) return contract == ContractDummy.MethodContract ? null : contract;
MethodContract result = new MethodContract();
IMethodContract primaryContract = this.primaryExtractor.GetMethodContractFor(method);
bool found = false;
if (primaryContract != null) {
found = true;
Microsoft.Cci.MutableContracts.ContractHelper.AddMethodContract(result, primaryContract);
}
if (this.oobExtractors != null) {
foreach (var oobProvider in this.oobExtractors) {
IMethodReference methodReference = method as IMethodReference;
if (methodReference == null) continue; // REVIEW: Is there anything else it could be and still find a contract for it?
MappingMutator primaryToOobMapper = this.mapperForPrimaryToOob[oobProvider];
var oobMethod = primaryToOobMapper.Map(methodReference);
if (oobMethod == null) continue;
var oobContract = oobProvider.GetMethodContractFor(oobMethod);
if (oobContract == null) continue;
MappingMutator oobToPrimaryMapper = this.mapperForOobToPrimary[oobProvider];
oobContract = oobToPrimaryMapper.Map(oobContract);
var sps = new Microsoft.Cci.MutableContracts.SubstituteParameters(this.host, oobMethod.ResolvedMethod, methodReference.ResolvedMethod);
oobContract = sps.Visit(oobContract);
Microsoft.Cci.MutableContracts.ContractHelper.AddMethodContract(result, oobContract);
found = true;
}
}
// always cache so we don't try to extract more than once
if (found) {
this.underlyingContractProvider.AssociateMethodWithContract(method, result);
} else {
this.underlyingContractProvider.AssociateMethodWithContract(method, ContractDummy.MethodContract);
result = null;
}
return result;
} finally {
this.methodsBeingExtracted.RemoveAt(this.methodsBeingExtracted.Count - 1);
}
}
/// <summary>
/// Adds the rsd contract to the method, it is added as a postcondition where the rsd field of the type is less than or equal to limit
/// </summary>
protected FieldDefinition AddRsdContractToMethod(IMethodDefinition method, ITypeReference type, string rsdName, IExpression limit, IExpression cond)
{
var rsdField = GetRsdField(method, rsdName, type);
var newContract = new Microsoft.Cci.MutableContracts.MethodContract();
var postconditions = new List<IPostcondition>();
var limitCondition = new LessThanOrEqual()
{
LeftOperand = new BoundExpression()
{
Definition = rsdField,
Type = rsdField.Type
},
RightOperand = limit,
Type = _host.PlatformType.SystemBoolean,
};
var int32Type = new PlatformType(_host).SystemInt32;
if (cond != null)
{
//cond ==> tmp <= limit =~=
//!cond || tmp <= limit =~=
//!cond ? tmp <= limit : true
postconditions.Add(
new Microsoft.Cci.MutableContracts.PostCondition()
{
Condition = new Conditional()
{
Condition = new LogicalNot() { Operand = cond },
Type = int32Type,
ResultIfTrue = new CompileTimeConstant() { Type = int32Type, Value = 1 },
ResultIfFalse = limitCondition
},
OriginalSource = "!cond ? rsd <= limit : true",
}
);
}
else
{
postconditions.Add(
new Microsoft.Cci.MutableContracts.PostCondition()
{
Condition = limitCondition,
OriginalSource = "rsd <= limit",
}
);
}
newContract.Postconditions = postconditions;
var contract = _contractProvider.GetMethodContractFor(method);
if (contract != null)
{
Microsoft.Cci.MutableContracts.ContractHelper.AddMethodContract(newContract, contract);
}
_contractProvider.AssociateMethodWithContract(method, newContract);
return rsdField;
}
private static MethodContract FilterUserMessageAndLegacyPreconditions(IContractAwareHost host, IMethodContract contract, ITypeDefinition typeDefinition, bool keepLegacy) {
var mc = new MethodContract(contract);
mc.Postconditions = FilterUserMessage(host, contract.Postconditions, typeDefinition);
mc.Preconditions = FilterUserMessageAndLegacyPreconditions(host, contract.Preconditions, typeDefinition, keepLegacy);
mc.ThrownExceptions = FilterUserMessage(host, contract.ThrownExceptions, typeDefinition);
return mc;
}
/// <summary>
/// Returns a method contract containing the 'effective' contract for the given
/// method definition. The effective contract contains all contracts for the method:
/// any that it has on its own, as well as all those inherited from any methods
/// that it overrides or interface methods that it implements (either implicitly
/// or explicitly).
/// All parameters in inherited contracts are substituted for by
/// the method's own parameters.
/// If there are no contracts, then it returns null.
/// Any preconditions that were written as legacy-preconditions or calls to Requires<E> are
/// included iff <paramref name="keepLegacyPreconditions"/>.
/// </summary>
public static IMethodContract GetMethodContractForIncludingInheritedContracts(IContractAwareHost host, IMethodDefinition methodDefinition, bool keepLegacyPreconditions = true) {
MethodContract cumulativeContract = new MethodContract();
bool atLeastOneContract = false;
IMethodContract/*?*/ mc = ContractHelper.GetMethodContractFor(host, methodDefinition);
if (mc != null) {
Microsoft.Cci.MutableContracts.ContractHelper.AddMethodContract(cumulativeContract, mc);
atLeastOneContract = true;
}
#region Overrides of base class methods
if (!methodDefinition.IsNewSlot) { // REVIEW: Is there a better test?
IMethodDefinition overriddenMethod = MemberHelper.GetImplicitlyOverriddenBaseClassMethod(methodDefinition) as IMethodDefinition;
while (overriddenMethod != null && !(overriddenMethod is Dummy)) {
IMethodContract/*?*/ overriddenContract = ContractHelper.GetMethodContractFor(host, overriddenMethod);
if (overriddenContract != null) {
overriddenContract = CopyContractIntoNewContext(host, overriddenContract, methodDefinition, overriddenMethod);
overriddenContract = FilterUserMessageAndLegacyPreconditions(host, overriddenContract, methodDefinition.ContainingTypeDefinition, keepLegacyPreconditions);
// if the method is generic, then need to specialize the contract to have the same method type parameters as the method
if (methodDefinition.IsGeneric) {
var d = new Dictionary<uint, ITypeReference>();
IteratorHelper.Zip(overriddenMethod.GenericParameters, methodDefinition.GenericParameters, (i, j) => d.Add(i.InternedKey, j));
var cs = new CodeSpecializer(host, d);
overriddenContract = cs.Rewrite(overriddenContract);
}
Microsoft.Cci.MutableContracts.ContractHelper.AddMethodContract(cumulativeContract, overriddenContract);
atLeastOneContract = true;
}
overriddenMethod = MemberHelper.GetImplicitlyOverriddenBaseClassMethod(overriddenMethod) as IMethodDefinition;
}
}
#endregion Overrides of base class methods
#region Implicit interface implementations
foreach (IMethodDefinition ifaceMethod in ContractHelper.GetAllImplicitlyImplementedInterfaceMethods(methodDefinition)) {
IMethodContract/*?*/ ifaceContract = ContractHelper.GetMethodContractFor(host, ifaceMethod);
if (ifaceContract == null) continue;
ifaceContract = CopyContractIntoNewContext(host, ifaceContract, methodDefinition, ifaceMethod);
ifaceContract = FilterUserMessageAndLegacyPreconditions(host, ifaceContract, methodDefinition.ContainingTypeDefinition, keepLegacyPreconditions);
Microsoft.Cci.MutableContracts.ContractHelper.AddMethodContract(cumulativeContract, ifaceContract);
atLeastOneContract = true;
}
#endregion Implicit interface implementations
#region Explicit interface implementations and explicit method overrides
foreach (IMethodReference ifaceMethodRef in MemberHelper.GetExplicitlyOverriddenMethods(methodDefinition)) {
IMethodDefinition/*?*/ ifaceMethod = ifaceMethodRef.ResolvedMethod;
if (ifaceMethod == null) continue;
IMethodContract/*?*/ ifaceContract = ContractHelper.GetMethodContractFor(host, ifaceMethod);
if (ifaceContract == null) continue;
ifaceContract = CopyContractIntoNewContext(host, ifaceContract, methodDefinition, ifaceMethod);
ifaceContract = FilterUserMessageAndLegacyPreconditions(host, ifaceContract, methodDefinition.ContainingTypeDefinition, keepLegacyPreconditions);
Microsoft.Cci.MutableContracts.ContractHelper.AddMethodContract(cumulativeContract, ifaceContract);
atLeastOneContract = true;
}
#endregion Explicit interface implementations and explicit method overrides
return atLeastOneContract ? cumulativeContract : null;
}
/// <summary>
/// Given a method definition for a getter or setter that the compiler produced for an auto-property,
/// mine the type contract and extract contracts from any invariants that mention the property.
/// If the <paramref name="methodDefinition"/> is a getter, then the returned method contract contains
/// only postconditions.
/// If the <paramref name="methodDefinition"/> is a setter, then the returned method contract contains
/// only preconditions.
/// If an invariant does not mention the property, then it is not represented in the returned contract.
/// </summary>
/// <param name="host"></param>
/// <param name="typeContract">
/// This must be the type contract corresponding to the containing type of <paramref name="methodDefinition"/>.
/// </param>
/// <param name="methodDefinition">
/// A method definition that should be a getter or setter for an auto-property. If it is not, then null is returned.
/// </param>
/// <returns>Either null or a method contract containing pre- or postconditions (mutually exclusive)
/// mined from the invariants contained in the <paramref name="typeContract"/>.
/// </returns>
public static MethodContract/*?*/ GetAutoPropertyContract(IMetadataHost host, ITypeContract typeContract, IMethodDefinition methodDefinition) {
// If the method was generated for an auto-property, then need to see if a contract can be derived by mining the invariant.
if (!methodDefinition.IsSpecialName) return null;
bool isPropertyGetter = methodDefinition.Name.Value.StartsWith("get_");
bool isPropertySetter = methodDefinition.Name.Value.StartsWith("set_");
//^ assume !(isPropertyGetter && isPropertySetter); // maybe neither, but never both!
if (!ContractHelper.IsAutoPropertyMember(host, methodDefinition)) return null;
IMethodDefinition getter = null;
IMethodDefinition setter = null;
// needs to have both a setter and a getter
var ct = methodDefinition.ContainingTypeDefinition;
if (isPropertyGetter) {
getter = methodDefinition;
var mms = ct.GetMatchingMembersNamed(host.NameTable.GetNameFor("set_" + methodDefinition.Name.Value.Substring(4)), false, md => ContractHelper.IsAutoPropertyMember(host, md));
foreach (var mem in mms) {
setter = mem as IMethodDefinition;
break;
}
} else { // isPropertySetter
setter = methodDefinition;
var mms = ct.GetMatchingMembersNamed(host.NameTable.GetNameFor("get_" + methodDefinition.Name.Value.Substring(4)), false, md => ContractHelper.IsAutoPropertyMember(host, md));
foreach (var mem in mms) {
getter = mem as IMethodDefinition;
break;
}
}
// Silent error?
if (getter == null || setter == null) return null;
// If the auto-property inherits any contracts then it doesn't derive any from the invariant
var inheritsContract = false;
IMethodDefinition overriddenMethod = MemberHelper.GetImplicitlyOverriddenBaseClassMethod(getter) as IMethodDefinition;
var isOverride = getter.IsNewSlot && overriddenMethod != null && !(overriddenMethod is Dummy);
inheritsContract |= isOverride;
if (!inheritsContract) {
inheritsContract |= IteratorHelper.EnumerableIsNotEmpty(ContractHelper.GetAllImplicitlyImplementedInterfaceMethods(getter));
}
if (!inheritsContract) {
inheritsContract |= IteratorHelper.EnumerableIsNotEmpty(MemberHelper.GetExplicitlyOverriddenMethods(getter));
}
if (inheritsContract) return null;
if (typeContract == null) return null;
MethodContract derivedMethodContract = null;
if (isPropertyGetter) {
var derivedPostConditions = new List<IPostcondition>();
foreach (var i in typeContract.Invariants) {
if (!MemberFinder.ExpressionContains(i.Condition, getter)) continue;
var v = Visibility.MostRestrictiveVisibility(host, i.Condition);
var currentVisibility = getter.Visibility;
var intersection = TypeHelper.VisibilityIntersection(v, currentVisibility);
if (intersection != currentVisibility) continue;
derivedPostConditions.Add(
new Postcondition() {
Condition = ReplaceAutoPropGetter.MakeEnsures(host, getter, i.Condition),
Description = i.Description,
OriginalSource = i.OriginalSource,
Locations = new List<ILocation>(i.Locations),
});
}
if (0 < derivedPostConditions.Count) {
derivedMethodContract = new MethodContract() {
Postconditions = derivedPostConditions,
};
}
} else { // isPropertySetter
var derivedPreconditions = new List<IPrecondition>();
foreach (var i in typeContract.Invariants) {
if (!MemberFinder.ExpressionContains(i.Condition, getter)) continue;
var v = Visibility.MostRestrictiveVisibility(host, i.Condition);
var currentVisibility = setter.Visibility;
var intersection = TypeHelper.VisibilityIntersection(v, currentVisibility);
if (intersection != currentVisibility) continue;
derivedPreconditions.Add(
new Precondition() {
Condition = ReplaceAutoPropGetter.MakeRequires(host, getter, setter, i.Condition),
Description = i.Description,
OriginalSource = i.OriginalSource,
Locations = new List<ILocation>(i.Locations),
});
}
if (0 < derivedPreconditions.Count) {
derivedMethodContract = new MethodContract() {
Preconditions = derivedPreconditions,
};
}
}
return derivedMethodContract;
}
