/// <summary>
/// Stores the value on the top of the stack in the reference.
/// </summary>
/// <param name="generator"> The generator to output the CIL to. </param>
/// <param name="optimizationInfo"> Information about any optimizations that should be performed. </param>
/// <param name="valueType"> The primitive type of the value that is on the top of the stack. </param>
/// <param name="throwIfUnresolvable"> <c>true</c> to throw a ReferenceError exception if
/// the name is unresolvable; <c>false</c> to create a new property instead. </param>
public void GenerateSet(ILGenerator generator, OptimizationInfo optimizationInfo, PrimitiveType valueType, bool throwIfUnresolvable)
{
// The value is initially on the top of the stack but is stored in this variable
// at the last possible moment.
ILLocalVariable value = null;
var scope = this.Scope;
ILLocalVariable scopeVariable = null;
var endOfSet = generator.CreateLabel();
do
{
if (scope is DeclarativeScope)
{
// Get information about the variable.
var variable = scope.GetDeclaredVariable(this.Name);
if (variable != null)
{
// The variable was declared in this scope.
if (scope.ExistsAtRuntime == false)
{
// The scope has been optimized away. The value of the variable is stored
// in an ILVariable.
// Declare an IL local variable if no storage location has been allocated yet.
if (variable.Store == null)
{
variable.Store = generator.DeclareVariable(typeof(object), variable.Name);
}
if (value == null)
{
// The value to store is on the top of the stack - convert it to the
// storage type of the variable.
EmitConversion.Convert(generator, valueType, variable.Type, optimizationInfo);
}
else
{
// The value to store is in a temporary variable.
generator.LoadVariable(value);
EmitConversion.Convert(generator, PrimitiveType.Any, variable.Type, optimizationInfo);
}
// Store the value in the variable.
generator.StoreVariable(variable.Store);
}
else if (variable.Writable == true)
{
if (value == null)
{
// The value to store is on the top of the stack - convert it to an
// object and store it in a temporary variable.
EmitConversion.Convert(generator, valueType, PrimitiveType.Any, optimizationInfo);
value = generator.CreateTemporaryVariable(typeof(object));
generator.StoreVariable(value);
}
// scope.Values[index] = value
if (scopeVariable == null)
{
EmitHelpers.LoadScope(generator);
}
else
{
generator.LoadVariable(scopeVariable);
}
generator.CastClass(typeof(DeclarativeScope));
generator.Call(ReflectionHelpers.DeclarativeScope_Values);
generator.LoadInt32(variable.Index);
generator.LoadVariable(value);
generator.StoreArrayElement(typeof(object));
}
else
{
// The variable exists, but is read-only.
// Pop the value off the stack (if it is still there).
if (value == null)
{
generator.Pop();
}
}
// The variable was found - no need to search any more parent scopes.
break;
}
else
{
// The variable was not defined at compile time, but may have been
// introduced by an eval() statement.
if (optimizationInfo.MethodOptimizationHints.HasEval == true)
{
if (value == null)
{
// The value to store is on the top of the stack - convert it to an
// object and store it in a temporary variable.
EmitConversion.Convert(generator, valueType, PrimitiveType.Any, optimizationInfo);
value = generator.CreateTemporaryVariable(typeof(object));
generator.StoreVariable(value);
}
// Check the variable exists: if (scope.HasValue(variableName) == true) {
if (scopeVariable == null)
{
EmitHelpers.LoadScope(generator);
}
else
{
generator.LoadVariable(scopeVariable);
}
generator.CastClass(typeof(DeclarativeScope));
generator.LoadString(this.Name);
generator.Call(ReflectionHelpers.Scope_HasValue);
var hasValueClause = generator.CreateLabel();
generator.BranchIfFalse(hasValueClause);
// Set the value of the variable.
if (scopeVariable == null)
{
EmitHelpers.LoadScope(generator);
}
else
{
generator.LoadVariable(scopeVariable);
}
generator.CastClass(typeof(DeclarativeScope));
generator.LoadString(this.Name);
generator.LoadVariable(value);
generator.Call(ReflectionHelpers.Scope_SetValue);
generator.Branch(endOfSet);
// }
generator.DefineLabelPosition(hasValueClause);
}
}
}
else
{
if (value == null)
{
// The value to store is on the top of the stack - convert it to an
// object and store it in a temporary variable.
EmitConversion.Convert(generator, valueType, PrimitiveType.Any, optimizationInfo);
value = generator.CreateTemporaryVariable(typeof(object));
generator.StoreVariable(value);
}
if (scopeVariable == null)
{
EmitHelpers.LoadScope(generator);
}
else
{
generator.LoadVariable(scopeVariable);
}
generator.CastClass(typeof(ObjectScope));
generator.Call(ReflectionHelpers.ObjectScope_ScopeObject);
if (scope.ParentScope == null && throwIfUnresolvable == false)
{
// Sets the value of a global variable.
// JS: object.property = value
// C# ==>
// if (propertyName == null)
// propertyName = new PropertyName("property");
// object.SetPropertyValue(propertyName, value, strictMode);
ILLocalVariable propertyName = optimizationInfo.GetGlobalPropertyReferenceVariable(generator, this.Name);
generator.LoadVariable(propertyName);
generator.Duplicate();
var afterIf = generator.CreateLabel();
generator.BranchIfNotNull(afterIf);
generator.Pop();
generator.LoadString(this.Name);
generator.NewObject(ReflectionHelpers.PropertyName_Constructor);
generator.Duplicate();
generator.StoreVariable(propertyName);
generator.DefineLabelPosition(afterIf);
generator.LoadVariable(value);
generator.LoadBoolean(optimizationInfo.StrictMode);
generator.Call(ReflectionHelpers.ObjectInstance_SetPropertyValue_PropertyReference);
}
else
{
// Setting a variable within a "with" scope.
generator.LoadString(this.Name);
generator.LoadVariable(value);
generator.LoadBoolean(optimizationInfo.StrictMode);
// Set the property value if the property exists.
generator.Call(ReflectionHelpers.ObjectInstance_SetPropertyValueIfExists);
// The return value is true if the property was defined, and false if it wasn't.
generator.BranchIfTrue(endOfSet);
}
}
// Try the parent scope.
if (scope.ParentScope != null && scope.ExistsAtRuntime == true)
{
if (scopeVariable == null)
{
scopeVariable = generator.CreateTemporaryVariable(typeof(Scope));
EmitHelpers.LoadScope(generator);
}
else
{
generator.LoadVariable(scopeVariable);
}
generator.Call(ReflectionHelpers.Scope_ParentScope);
generator.StoreVariable(scopeVariable);
}
scope = scope.ParentScope;
} while (scope != null);
// The value might be still on top of the stack.
if (value == null && scope == null)
{
generator.Pop();
}
// Throw an error if the name does not exist and throwIfUnresolvable is true.
if (scope == null && throwIfUnresolvable == true)
{
EmitHelpers.EmitThrow(generator, ErrorType.ReferenceError, this.Name + " is not defined", optimizationInfo);
}
// Release the temporary variables.
if (value != null)
{
generator.ReleaseTemporaryVariable(value);
}
if (scopeVariable != null)
{
generator.ReleaseTemporaryVariable(scopeVariable);
}
// Define a label at the end.
generator.DefineLabelPosition(endOfSet);
}
/// <summary>
/// Pushes the value of the reference onto the stack.
/// </summary>
/// <param name="generator"> The generator to output the CIL to. </param>
/// <param name="optimizationInfo"> Information about any optimizations that should be performed. </param>
/// <param name="throwIfUnresolvable"> <c>true</c> to throw a ReferenceError exception if
/// the name is unresolvable; <c>false</c> to output <c>null</c> instead. </param>
public void GenerateGet(ILGenerator generator, OptimizationInfo optimizationInfo, bool throwIfUnresolvable)
{
// This method generates code to retrieve the value of a variable, given the name of
// variable and scope in which the variable is being referenced. The variable was
// not necessary declared in this scope - it might be declared in any of the parent
// scopes (together called a scope chain). The general algorithm is to start at the
// head of the chain and search backwards until the variable is found. There are
// two types of scopes: declarative scopes and object scopes. Object scopes are hard -
// it cannot be known at compile time whether the variable exists or not so runtime
// checks have to be inserted. Declarative scopes are easier - variables have to be
// declared and cannot be deleted. There is one tricky bit: new variables can be
// introduced into a declarative scope at runtime by a non-strict eval() statement.
// Even worse, variables that were introduced by means of an eval() *can* be deleted.
var scope = this.Scope;
ILLocalVariable scopeVariable = null;
var endOfGet = generator.CreateLabel();
do
{
if (scope is DeclarativeScope)
{
// The variable was declared in this scope.
var variable = scope.GetDeclaredVariable(this.Name);
if (variable != null)
{
if (scope.ExistsAtRuntime == false)
{
// The scope has been optimized away. The value of the variable is stored
// in an ILVariable.
// Declare an IL local variable if no storage location has been allocated yet.
if (variable.Store == null)
{
variable.Store = generator.DeclareVariable(typeof(object), variable.Name);
}
// Load the value from the variable.
generator.LoadVariable(variable.Store);
// Ensure that we match ResultType.
EmitConversion.Convert(generator, variable.Type, this.ResultType, optimizationInfo);
}
else
{
// scope.Values[index]
if (scopeVariable == null)
{
EmitHelpers.LoadScope(generator);
}
else
{
generator.LoadVariable(scopeVariable);
}
generator.CastClass(typeof(DeclarativeScope));
generator.Call(ReflectionHelpers.DeclarativeScope_Values);
generator.LoadInt32(variable.Index);
generator.LoadArrayElement(typeof(object));
}
// The variable was found - no need to search any more parent scopes.
break;
}
else
{
// The variable was not defined at compile time, but may have been
// introduced by an eval() statement.
if (optimizationInfo.MethodOptimizationHints.HasEval == true)
{
// Check the variable exists: if (scope.HasValue(variableName) == true) {
if (scopeVariable == null)
{
EmitHelpers.LoadScope(generator);
}
else
{
generator.LoadVariable(scopeVariable);
}
generator.CastClass(typeof(DeclarativeScope));
generator.LoadString(this.Name);
generator.Call(ReflectionHelpers.Scope_HasValue);
var hasValueClause = generator.CreateLabel();
generator.BranchIfFalse(hasValueClause);
// Load the value of the variable.
if (scopeVariable == null)
{
EmitHelpers.LoadScope(generator);
}
else
{
generator.LoadVariable(scopeVariable);
}
generator.CastClass(typeof(DeclarativeScope));
generator.LoadString(this.Name);
generator.Call(ReflectionHelpers.Scope_GetValue);
generator.Branch(endOfGet);
// }
generator.DefineLabelPosition(hasValueClause);
}
}
}
else
{
if (scopeVariable == null)
{
EmitHelpers.LoadScope(generator);
}
else
{
generator.LoadVariable(scopeVariable);
}
generator.CastClass(typeof(ObjectScope));
generator.Call(ReflectionHelpers.ObjectScope_ScopeObject);
if (scope.ParentScope == null)
{
// Gets the value of a global variable.
// JS: object.property
// C# ==>
// if (propertyName == null)
// propertyName = new PropertyName("property");
// object.GetPropertyValue(propertyName);
ILLocalVariable propertyName = optimizationInfo.GetGlobalPropertyReferenceVariable(generator, this.Name);
generator.LoadVariable(propertyName);
generator.Duplicate();
var afterIf = generator.CreateLabel();
generator.BranchIfNotNull(afterIf);
generator.Pop();
generator.LoadString(this.Name);
generator.NewObject(ReflectionHelpers.PropertyName_Constructor);
generator.Duplicate();
generator.StoreVariable(propertyName);
generator.DefineLabelPosition(afterIf);
generator.Call(ReflectionHelpers.ObjectInstance_GetPropertyValue_PropertyReference);
}
else
{
// Gets the value of a variable in an object scope.
generator.LoadString(this.Name);
generator.Call(ReflectionHelpers.ObjectInstance_GetPropertyValue_Object);
}
// Check if the value is null.
generator.Duplicate();
generator.BranchIfNotNull(endOfGet);
if (scope.ParentScope != null)
{
generator.Pop();
}
}
// Try the parent scope.
if (scope.ParentScope != null && scope.ExistsAtRuntime == true)
{
if (scopeVariable == null)
{
scopeVariable = generator.CreateTemporaryVariable(typeof(Scope));
EmitHelpers.LoadScope(generator);
}
else
{
generator.LoadVariable(scopeVariable);
}
generator.Call(ReflectionHelpers.Scope_ParentScope);
generator.StoreVariable(scopeVariable);
}
scope = scope.ParentScope;
} while (scope != null);
// Throw an error if the name does not exist and throwIfUnresolvable is true.
if (scope == null && throwIfUnresolvable == true)
{
EmitHelpers.EmitThrow(generator, ErrorType.ReferenceError, this.Name + " is not defined", optimizationInfo);
}
// Release the temporary variable.
if (scopeVariable != null)
{
generator.ReleaseTemporaryVariable(scopeVariable);
}
// Define a label at the end.
generator.DefineLabelPosition(endOfGet);
// Object scope references may have side-effects (because of getters) so if the value
// is to be ignored we evaluate the value then pop the value from the stack.
//if (optimizationInfo.SuppressReturnValue == true)
// generator.Pop();
}
