/// <summary>
/// Emits IL instructions that load the "$this" variable onto the evaluation stack.
/// </summary>
private PhpTypeCode EmitLoadThis(CodeGenerator codeGenerator)
{
ILEmitter il = codeGenerator.IL;
CompilerLocationStack locationStack = codeGenerator.LocationStack;
// special treatment of $this
switch (locationStack.LocationType)
{
case LocationTypes.GlobalCode:
{
// load $this from one of Main's arguments and check for null
Label this_non_null = il.DefineLabel();
codeGenerator.EmitLoadSelf();
il.Emit(OpCodes.Dup);
il.Emit(OpCodes.Brtrue_S, this_non_null);
il.Emit(OpCodes.Ldstr, VariableName.ThisVariableName.Value);
codeGenerator.EmitPhpException(Methods.PhpException.UndefinedVariable);
il.MarkLabel(this_non_null, true);
return(PhpTypeCode.Object);
}
case LocationTypes.FunctionDecl:
{
// always null
il.Emit(OpCodes.Ldstr, VariableName.ThisVariableName.Value);
codeGenerator.EmitPhpException(Methods.PhpException.UndefinedVariable);
il.Emit(OpCodes.Ldnull);
return(PhpTypeCode.Object);
}
case LocationTypes.MethodDecl:
{
CompilerLocationStack.MethodDeclContext context = locationStack.PeekMethodDecl();
if (context.Method.IsStatic)
{
// always null in static methods
il.Emit(OpCodes.Ldstr, VariableName.ThisVariableName.Value);
codeGenerator.EmitPhpException(Methods.PhpException.UndefinedVariable);
il.Emit(OpCodes.Ldnull);
return(PhpTypeCode.Object);
}
else
{
// arg0 or <proxy> in instance methods
codeGenerator.EmitLoadSelf();
return(PhpTypeCode.DObject);
}
}
default:
Debug.Fail("Invalid location type.");
return(PhpTypeCode.Invalid);
}
}
/// <summary>
/// Loads a PhpReference to "this" special variable to the evaluation stack.
/// If "this" is not available, loads an empty PhpReference.
/// </summary>
private PhpTypeCode EmitLoadThisRef(CodeGenerator /*!*/ codeGenerator)
{
ILEmitter il = codeGenerator.IL;
switch (codeGenerator.LocationStack.LocationType)
{
case LocationTypes.GlobalCode:
{
// load $this from one of Main's arguments:
codeGenerator.EmitLoadSelf();
// NOTE: If $this is used by ref somewhere in the method each access to it is boxed to the reference.
// Only calls to methods use the "this" pointer itself. Thus the rule "no duplicate pointers" is slightly
// broken here yet everything should work fine.
il.Emit(OpCodes.Newobj, Constructors.PhpReference_Object);
break;
}
case LocationTypes.FunctionDecl:
{
// always null referencing PhpReference
il.Emit(OpCodes.Newobj, Constructors.PhpReference_Void);
break;
}
case LocationTypes.MethodDecl:
{
CompilerLocationStack.MethodDeclContext context = codeGenerator.LocationStack.PeekMethodDecl();
if (context.Method.IsStatic)
{
// always null referencing PhpReference in static methods
il.Emit(OpCodes.Newobj, Constructors.PhpReference_Void);
}
else
{
// arg0 or <proxy> referencing PhpReference in instance methods
codeGenerator.EmitLoadSelf();
// NOTE: If $this is used by ref somewhere in the method each access to it is boxed to the reference.
// Only calls to methods use the "this" pointer itself. Thus the rule "no duplicate pointers" is slightly
// broken here yet everything should work fine.
il.Emit(OpCodes.Newobj, Constructors.PhpReference_Object);
}
break;
}
default:
Debug.Fail("Invalid location type.");
break;
}
// always returns a reference:
return(PhpTypeCode.PhpReference);
}
/// <summary>
/// Emits IL instructions that prepare a field of $this for writing.
/// </summary>
private AssignmentCallback EmitWriteFieldOfThis(CodeGenerator /*!*/ codeGenerator, bool writeRef)
{
ILEmitter il = codeGenerator.IL;
// $this->a
switch (codeGenerator.LocationStack.LocationType)
{
case LocationTypes.GlobalCode:
{
// load $this from one of Main's arguments and check for null
Label this_non_null = il.DefineLabel();
codeGenerator.EmitLoadSelf();
il.Emit(OpCodes.Brtrue_S, this_non_null);
codeGenerator.EmitPhpException(Methods.PhpException.ThisUsedOutOfObjectContext);
il.Emit(OpCodes.Br, codeGenerator.ChainBuilder.ErrorLabel);
il.MarkLabel(this_non_null, true);
// prepare the stack for SetObjectProperty call
codeGenerator.EmitLoadSelf();
EmitName(codeGenerator);
return(new AssignmentCallback(EmitCallSetObjectField));
}
case LocationTypes.FunctionDecl:
{
// always throws error
codeGenerator.EmitPhpException(Methods.PhpException.ThisUsedOutOfObjectContext);
return(new AssignmentCallback(EmitPopValue));
}
case LocationTypes.MethodDecl:
{
CompilerLocationStack.MethodDeclContext context = codeGenerator.LocationStack.PeekMethodDecl();
if (context.Method.IsStatic)
{
// always throws error
codeGenerator.EmitPhpException(Methods.PhpException.ThisUsedOutOfObjectContext);
return(new AssignmentCallback(EmitPopValue));
}
// attempt direct field writing (DirectVarUse only)
return(EmitWriteFieldOfThisInInstanceMethod(codeGenerator, writeRef));
}
}
Debug.Fail("Invalid lcoation type.");
return(null);
}
/// <summary>
/// Emits IL instructions that read the value of a field of $this instance.
/// </summary>
/// <param name="codeGenerator">The current <see cref="CodeGenerator"/>.</param>
/// <param name="wantRef">If <B>false</B> the field value should be left on the evaluation stack,
/// if <B>true</B> the <see cref="PhpReference"/> should be left on the evaluation stack.</param>
/// <returns></returns>
private PhpTypeCode EmitReadFieldOfThis(CodeGenerator /*!*/ codeGenerator, bool wantRef)
{
ILEmitter il = codeGenerator.IL;
// $this->a
switch (codeGenerator.LocationStack.LocationType)
{
case LocationTypes.GlobalCode:
{
// load $this from one of Main's arguments and check for null
Label this_non_null = il.DefineLabel();
Label reading_over = il.DefineLabel();
codeGenerator.EmitLoadSelf();
il.Emit(OpCodes.Brtrue_S, this_non_null);
EmitThisUsedOutOfObjectThrow(codeGenerator, wantRef);
il.Emit(OpCodes.Br, reading_over);
il.MarkLabel(this_non_null, true);
// call GetObjectProperty/GetObjectPropertyRef
EmitGetFieldOfPlace(codeGenerator.SelfPlace, codeGenerator, wantRef);
il.MarkLabel(reading_over, true);
break;
}
case LocationTypes.FunctionDecl:
{
EmitThisUsedOutOfObjectThrow(codeGenerator, wantRef);
break;
}
case LocationTypes.MethodDecl:
{
CompilerLocationStack.MethodDeclContext context = codeGenerator.LocationStack.PeekMethodDecl();
if (context.Method.IsStatic)
{
EmitThisUsedOutOfObjectThrow(codeGenerator, wantRef);
break;
}
// attempt direct field reading (DirectVarUse only)
return(EmitReadFieldOfThisInInstanceMethod(codeGenerator, wantRef));
}
}
return(wantRef ? PhpTypeCode.PhpReference : PhpTypeCode.Object);
}
internal override PhpTypeCode EmitIsset(CodeGenerator codeGenerator, bool empty)
{
// Template: "isset(x)" x != null
// isset doesn't distinguish between the NULL and uninitialized variable
// a reference is dereferenced, i.e. isset tells us whether the referenced variable is set
Debug.Assert(access == AccessType.Read);
// Cases 1, 4, 5, 6, 9 never reached
Debug.Assert(codeGenerator.ChainBuilder.IsMember == false);
// Case 3 never reached
Debug.Assert(codeGenerator.ChainBuilder.IsArrayItem == false);
codeGenerator.ChainBuilder.QuietRead = true;
// 2,7,8
if (this.isMemberOf != null)
{
// 2: $b->a
// 8: b[]->a
codeGenerator.ChainBuilder.Create();
codeGenerator.ChainBuilder.Begin();
codeGenerator.ChainBuilder.QuietRead = true;
EmitReadField(codeGenerator, false);
codeGenerator.ChainBuilder.End();
return(PhpTypeCode.Object);
}
// 7: $a
// Check whether this variable is set
//codeGenerator.EmitVariableIsset(this);
ILEmitter il = codeGenerator.IL;
if (varName.IsThisVariableName && codeGenerator.LocationStack.LocationType == LocationTypes.MethodDecl)
{
CompilerLocationStack.MethodDeclContext context = codeGenerator.LocationStack.PeekMethodDecl();
if (!context.Method.IsStatic)
{
// $this is always set in instance methods
il.Emit(OpCodes.Ldarg_0);
return(PhpTypeCode.Object);
}
}
this.EmitLoad(codeGenerator);
return(PhpTypeCode.Object);
}
/// <summary>
/// Emits IL instructions that unset an instance field.
/// </summary>
/// <remarks>
/// Nothing is expected on the evaluation stack. Nothing is left on the evaluation stack.
/// </remarks>
private void EmitUnsetField(CodeGenerator /*!*/ codeGenerator)
{
ILEmitter il = codeGenerator.IL;
DirectVarUse direct_instance = isMemberOf as DirectVarUse;
if (direct_instance != null && direct_instance.VarName.IsThisVariableName)
{
// $this->a
switch (codeGenerator.LocationStack.LocationType)
{
case LocationTypes.GlobalCode:
{
// load $this from one of Main's arguments and check for null
Label this_non_null = il.DefineLabel();
codeGenerator.EmitLoadSelf();
il.Emit(OpCodes.Brtrue_S, this_non_null);
codeGenerator.EmitPhpException(Methods.PhpException.ThisUsedOutOfObjectContext);
il.Emit(OpCodes.Br, codeGenerator.ChainBuilder.ErrorLabel);
il.MarkLabel(this_non_null, true);
// call UnsetProperty
codeGenerator.EmitLoadSelf();
il.Emit(OpCodes.Ldstr, varName.ToString()); // TODO
codeGenerator.EmitLoadClassContext();
il.EmitCall(OpCodes.Call, Methods.Operators.UnsetProperty, null);
return;
}
case LocationTypes.FunctionDecl:
{
// always throws error
codeGenerator.EmitPhpException(Methods.PhpException.ThisUsedOutOfObjectContext);
il.Emit(OpCodes.Br, codeGenerator.ChainBuilder.ErrorLabel);
break;
}
case LocationTypes.MethodDecl:
{
CompilerLocationStack.MethodDeclContext context = codeGenerator.LocationStack.PeekMethodDecl();
if (context.Method.IsStatic)
{
// always throws error
codeGenerator.EmitPhpException(Methods.PhpException.ThisUsedOutOfObjectContext);
il.Emit(OpCodes.Br, codeGenerator.ChainBuilder.ErrorLabel);
}
else
{
DProperty property;
if (context.Type.GetProperty(varName, context.Type, out property) == GetMemberResult.OK &&
!property.IsStatic)
{
// ask the DProperty to emit its unsetting code
property.EmitUnset(codeGenerator, IndexedPlace.ThisArg, null, false);
}
else
{
// unable to resolve the field -> call UnsetProperty
codeGenerator.EmitLoadSelf();
il.Emit(OpCodes.Ldstr, varName.ToString());
codeGenerator.EmitLoadClassContext();
il.EmitCall(OpCodes.Call, Methods.Operators.UnsetProperty, null);
}
}
}
break;
}
}
else
{
// call UnsetProperty
isMemberOf.Emit(codeGenerator);
il.Emit(OpCodes.Ldstr, varName.ToString());
codeGenerator.EmitLoadClassContext();
il.EmitCall(OpCodes.Call, Methods.Operators.UnsetProperty, null);
}
}
