//
// Author:
// Miguel de Icaza (miguel@ximian.com)
+// Martin Baulig (martin@ximian.com)
//
-// (C) 2001 Ximian, Inc.
+// (C) 2001, 2002, 2003 Ximian, Inc.
+// (C) 2004 Novell, Inc
//
using System;
using System.Reflection;
using System.Reflection.Emit;
-namespace CIR {
-
- // <remarks>
- // This interface is implemented by Expressions whose values can not
- // store the result on the top of the stack.
- //
- // Expressions implementing this (Properties, Indexers and Arrays) would
- // perform an assignment of the Expression "source" into its final
- // location.
- //
- // No values on the top of the stack are expected to be left by
- // invoking this method.
- // </remarks>
+namespace Mono.CSharp {
+
+ /// <summary>
+ /// This interface is implemented by expressions that can be assigned to.
+ /// </summary>
+ /// <remarks>
+ /// This interface is implemented by Expressions whose values can not
+ /// store the result on the top of the stack.
+ ///
+ /// Expressions implementing this (Properties, Indexers and Arrays) would
+ /// perform an assignment of the Expression "source" into its final
+ /// location.
+ ///
+ /// No values on the top of the stack are expected to be left by
+ /// invoking this method.
+ /// </remarks>
public interface IAssignMethod {
- void EmitAssign (EmitContext ec, Expression source);
+ //
+ // This is an extra version of Emit. If leave_copy is `true'
+ // A copy of the expression will be left on the stack at the
+ // end of the code generated for EmitAssign
+ //
+ void Emit (EmitContext ec, bool leave_copy);
+
+ //
+ // This method does the assignment
+ // `source' will be stored into the location specified by `this'
+ // if `leave_copy' is true, a copy of `source' will be left on the stack
+ // if `prepare_for_load' is true, when `source' is emitted, there will
+ // be data on the stack that it can use to compuatate its value. This is
+ // for expressions like a [f ()] ++, where you can't call `f ()' twice.
+ //
+ void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load);
+
+ /*
+ For simple assignments, this interface is very simple, EmitAssign is called with source
+ as the source expression and leave_copy and prepare_for_load false.
+
+ For compound assignments it gets complicated.
+
+ EmitAssign will be called as before, however, prepare_for_load will be
+ true. The @source expression will contain an expression
+ which calls Emit. So, the calls look like:
+
+ this.EmitAssign (ec, source, false, true) ->
+ source.Emit (ec); ->
+ [...] ->
+ this.Emit (ec, false); ->
+ end this.Emit (ec, false); ->
+ end [...]
+ end source.Emit (ec);
+ end this.EmitAssign (ec, source, false, true)
+
+
+ When prepare_for_load is true, EmitAssign emits a `token' on the stack that
+ Emit will use for its state.
+
+ Let's take FieldExpr as an example. assume we are emitting f ().y += 1;
+
+ Here is the call tree again. This time, each call is annotated with the IL
+ it produces:
+
+ this.EmitAssign (ec, source, false, true)
+ call f
+ dup
+
+ Binary.Emit ()
+ this.Emit (ec, false);
+ ldfld y
+ end this.Emit (ec, false);
+
+ IntConstant.Emit ()
+ ldc.i4.1
+ end IntConstant.Emit
+
+ add
+ end Binary.Emit ()
+
+ stfld
+ end this.EmitAssign (ec, source, false, true)
+
+ Observe two things:
+ 1) EmitAssign left a token on the stack. It was the result of f ().
+ 2) This token was used by Emit
+
+ leave_copy (in both EmitAssign and Emit) tells the compiler to leave a copy
+ of the expression at that point in evaluation. This is used for pre/post inc/dec
+ and for a = x += y. Let's do the above example with leave_copy true in EmitAssign
+
+ this.EmitAssign (ec, source, true, true)
+ call f
+ dup
+
+ Binary.Emit ()
+ this.Emit (ec, false);
+ ldfld y
+ end this.Emit (ec, false);
+
+ IntConstant.Emit ()
+ ldc.i4.1
+ end IntConstant.Emit
+
+ add
+ end Binary.Emit ()
+
+ dup
+ stloc temp
+ stfld
+ ldloc temp
+ end this.EmitAssign (ec, source, true, true)
+
+ And with it true in Emit
+
+ this.EmitAssign (ec, source, false, true)
+ call f
+ dup
+
+ Binary.Emit ()
+ this.Emit (ec, true);
+ ldfld y
+ dup
+ stloc temp
+ end this.Emit (ec, true);
+
+ IntConstant.Emit ()
+ ldc.i4.1
+ end IntConstant.Emit
+
+ add
+ end Binary.Emit ()
+
+ stfld
+ ldloc temp
+ end this.EmitAssign (ec, source, false, true)
+
+ Note that these two examples are what happens for ++x and x++, respectively.
+ */
}
- // <remarks>
- // The LocalTemporary class is used to hold temporary values of a given
- // type to "simulate" the expression semantics on property and indexer
- // access whose return values are void.
- //
- // The local temporary is used to alter the normal flow of code generation
- // basically it creates a local variable, and its emit instruction generates
- // code to access this value, return its address or save its value.
- // </remarks>
- public class LocalTemporary : Expression, IStackStore, IMemoryLocation {
+ /// <summary>
+ /// An Expression to hold a temporary value.
+ /// </summary>
+ /// <remarks>
+ /// The LocalTemporary class is used to hold temporary values of a given
+ /// type to "simulate" the expression semantics on property and indexer
+ /// access whose return values are void.
+ ///
+ /// The local temporary is used to alter the normal flow of code generation
+ /// basically it creates a local variable, and its emit instruction generates
+ /// code to access this value, return its address or save its value.
+ ///
+ /// If `is_address' is true, then the value that we store is the address to the
+ /// real value, and not the value itself.
+ ///
+ /// This is needed for a value type, because otherwise you just end up making a
+ /// copy of the value on the stack and modifying it. You really need a pointer
+ /// to the origional value so that you can modify it in that location. This
+ /// Does not happen with a class because a class is a pointer -- so you always
+ /// get the indirection.
+ ///
+ /// The `is_address' stuff is really just a hack. We need to come up with a better
+ /// way to handle it.
+ /// </remarks>
+ public class LocalTemporary : Expression, IMemoryLocation {
LocalBuilder builder;
+ bool is_address;
- public LocalTemporary (EmitContext ec, Type t)
+ public LocalTemporary (EmitContext ec, Type t) : this (ec, t, false) {}
+
+ public LocalTemporary (EmitContext ec, Type t, bool is_address)
+ {
+ type = t;
+ eclass = ExprClass.Value;
+ loc = Location.Null;
+ builder = ec.GetTemporaryLocal (is_address ? TypeManager.GetReferenceType (t): t);
+ this.is_address = is_address;
+ }
+
+ public LocalTemporary (LocalBuilder b, Type t)
{
type = t;
eclass = ExprClass.Value;
- builder = ec.GetTemporaryStorage (t);
+ loc = Location.Null;
+ builder = b;
}
+ public void Release (EmitContext ec)
+ {
+ ec.FreeTemporaryLocal (builder, type);
+ builder = null;
+ }
+
public override Expression DoResolve (EmitContext ec)
{
return this;
public override void Emit (EmitContext ec)
{
- ec.ig.Emit (OpCodes.Ldloc, builder);
+ ILGenerator ig = ec.ig;
+
+ ig.Emit (OpCodes.Ldloc, builder);
+ // we need to copy from the pointer
+ if (is_address)
+ LoadFromPtr (ig, type);
}
+ // NB: if you have `is_address' on the stack there must
+ // be a managed pointer. Otherwise, it is the type from
+ // the ctor.
public void Store (EmitContext ec)
{
- ec.ig.Emit (OpCodes.Stloc, builder);
+ ILGenerator ig = ec.ig;
+ ig.Emit (OpCodes.Stloc, builder);
}
- public void AddressOf (EmitContext ec)
+ public void AddressOf (EmitContext ec, AddressOp mode)
{
- ec.ig.Emit (OpCodes.Ldloca, builder);
+ // if is_address, than this is just the address anyways,
+ // so we just return this.
+ ILGenerator ig = ec.ig;
+
+ if (is_address)
+ ig.Emit (OpCodes.Ldloc, builder);
+ else
+ ig.Emit (OpCodes.Ldloca, builder);
+ }
+
+ public bool PointsToAddress {
+ get {
+ return is_address;
+ }
}
}
- // <remarks>
- // The Assign node takes care of assigning the value of source into
- // the expression represented by target.
- // </remarks>
+ /// <summary>
+ /// The Assign node takes care of assigning the value of source into
+ /// the expression represented by target.
+ /// </summary>
public class Assign : ExpressionStatement {
- Expression target, source;
- Location l;
-
+ protected Expression target, source, real_source;
+ protected LocalTemporary temp = null, real_temp = null;
+ protected Assign embedded = null;
+ protected bool is_embedded = false;
+ protected bool must_free_temp = false;
+
public Assign (Expression target, Expression source, Location l)
{
this.target = target;
- this.source = source;
- this.l = l;
+ this.source = this.real_source = source;
+ this.loc = l;
+ }
+
+ protected Assign (Assign embedded, Location l)
+ : this (embedded.target, embedded.source, l)
+ {
+ this.is_embedded = true;
+ }
+
+ protected virtual Assign GetEmbeddedAssign (Location loc)
+ {
+ return new Assign (this, loc);
}
public Expression Target {
}
}
+ public static void error70 (EventInfo ei, Location l)
+ {
+ Report.Error (70, l, "The event '" + ei.Name +
+ "' can only appear on the left-side of a += or -= (except when" +
+ " used from within the type '" + ei.DeclaringType + "')");
+ }
+
+ //
+ // Will return either `this' or an instance of `New'.
+ //
public override Expression DoResolve (EmitContext ec)
{
- source = source.Resolve (ec);
- if (source == null)
+ // Create an embedded assignment if our source is an assignment.
+ if (source is Assign)
+ source = embedded = ((Assign) source).GetEmbeddedAssign (loc);
+
+ real_source = source = source.Resolve (ec);
+ if (source == null) {
+ // Ensure that we don't propagate the error as spurious "uninitialized variable" errors.
+ target = target.ResolveLValue (ec, EmptyExpression.Null, Location);
return null;
+ }
+
+ //
+ // This is used in an embedded assignment.
+ // As an example, consider the statement "A = X = Y = Z".
+ //
+ if (is_embedded && !(source is Constant)) {
+ // If this is the innermost assignment (the "Y = Z" in our example),
+ // create a new temporary local, otherwise inherit that variable
+ // from our child (the "X = (Y = Z)" inherits the local from the
+ // "Y = Z" assignment).
+
+ if (embedded == null) {
+ if (this is CompoundAssign)
+ real_temp = temp = new LocalTemporary (ec, target.Type);
+ else
+ real_temp = temp = new LocalTemporary (ec, source.Type);
+ } else
+ temp = embedded.temp;
+
+ // Set the source to the new temporary variable.
+ // This means that the following target.ResolveLValue () will tell
+ // the target to read it's source value from that variable.
+ source = temp;
+ }
+
+ // If we have an embedded assignment, use the embedded assignment's temporary
+ // local variable as source.
+ if (embedded != null)
+ source = (embedded.temp != null) ? embedded.temp : embedded.source;
+
+ target = target.ResolveLValue (ec, source, Location);
- target = target.ResolveLValue (ec, source);
-
if (target == null)
return null;
- Console.WriteLine ("Resolving: " + source + "/" + source.Type + " [ " + target
- + "/ " + target.Type + "]");
+ if (source.Equals (target)) {
+ Report.Warning (1717, 3, loc, "Assignment made to same variable; did you mean to assign something else?");
+ }
Type target_type = target.Type;
- Type source_type = source.Type;
-
- type = target_type;
+ Type source_type = real_source.Type;
+
+ // If we're an embedded assignment, our parent will reuse our source as its
+ // source, it won't read from our target.
+ if (is_embedded)
+ type = source_type;
+ else
+ type = target_type;
eclass = ExprClass.Value;
-
- //
- // If we are doing a property assignment, then
- // set the `value' field on the property, and Resolve
- // it.
- //
- if (target is PropertyExpr){
- PropertyExpr property_assign = (PropertyExpr) target;
- //
- // FIXME: Maybe handle this in the LValueResolve
- //
- if (!property_assign.VerifyAssignable ())
+
+ if (target is EventExpr) {
+ EventInfo ei = ((EventExpr) target).EventInfo;
+
+ Expression ml = MemberLookup (
+ ec, ec.ContainerType, ei.Name,
+ MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
+
+ if (ml == null) {
+ //
+ // If this is the case, then the Event does not belong
+ // to this Type and so, according to the spec
+ // is allowed to only appear on the left hand of
+ // the += and -= operators
+ //
+ // Note that target will not appear as an EventExpr
+ // in the case it is being referenced within the same type container;
+ // it will appear as a FieldExpr in that case.
+ //
+
+ if (!(source is BinaryDelegate)) {
+ error70 (ei, loc);
+ return null;
+ }
+ }
+ }
+
+ FieldExpr field_exp = target as FieldExpr;
+ if (field_exp != null && field_exp.DeclaringType.IsValueType && !ec.IsConstructor && !ec.IsFieldInitializer) {
+ field_exp = field_exp.InstanceExpression as FieldExpr;
+ if (field_exp != null && field_exp.FieldInfo.IsInitOnly) {
+ if (field_exp.IsStatic) {
+ Report.Error (1650, loc, "Members of static readonly field '{0}' cannot be assigned to " +
+ "(except in a static constructor or a variable initializer)", TypeManager.GetFullNameSignature (field_exp.FieldInfo));
+ } else {
+ Report.Error (1648, loc, "Members of readonly field '{0}' cannot be assigned to " +
+ "(except in a constructor or a variable initializer)", TypeManager.GetFullNameSignature (field_exp.FieldInfo));
+ }
return null;
-
- return this;
+ }
}
- if (target is IndexerAccess){
- IndexerAccess ia = (IndexerAccess) target;
-
- return this;
+ if (!(target is IAssignMethod) && (target.eclass != ExprClass.EventAccess)) {
+ Report.Error (131, loc,
+ "Left hand of an assignment must be a variable, " +
+ "a property or an indexer");
+ return null;
}
- if (source is New && target_type.IsSubclassOf (TypeManager.value_type)){
- New n = (New) source;
+ if ((source.eclass == ExprClass.Type) && (source is TypeExpr)) {
+ source.Error_UnexpectedKind ("variable or value", loc);
+ return null;
+ } else if ((RootContext.Version == LanguageVersion.ISO_1) &&
+ (source is MethodGroupExpr)){
+ ((MethodGroupExpr) source).ReportUsageError ();
+ return null;
- n.ValueTypeVariable = target;
+ }
- return n;
+ if (target_type == source_type){
+ if (source is New && target_type.IsValueType &&
+ (target.eclass != ExprClass.IndexerAccess) && (target.eclass != ExprClass.PropertyAccess)){
+ New n = (New) source;
+
+ if (n.SetValueTypeVariable (target))
+ return n;
+ else
+ return null;
+ }
+
+ return this;
}
+
+ //
+ // If this assignemnt/operator was part of a compound binary
+ // operator, then we allow an explicit conversion, as detailed
+ // in the spec.
+ //
- if (target_type != source_type){
- source = ConvertImplicitRequired (ec, source, target_type, l);
- if (source == null)
+ if (this is CompoundAssign){
+ CompoundAssign a = (CompoundAssign) this;
+
+ Binary b = source as Binary;
+ if (b != null){
+ //
+ // 1. if the source is explicitly convertible to the
+ // target_type
+ //
+
+ source = Convert.ExplicitConversion (ec, source, target_type, loc);
+ if (source == null){
+ Convert.Error_CannotImplicitConversion (loc, source_type, target_type);
+ return null;
+ }
+
+ //
+ // 2. and the original right side is implicitly convertible to
+ // the type of target
+ //
+ if (Convert.ImplicitStandardConversionExists (ec, a.original_source, target_type))
+ return this;
+
+ //
+ // In the spec 2.4 they added: or if type of the target is int
+ // and the operator is a shift operator...
+ //
+ if (source_type == TypeManager.int32_type &&
+ (b.Oper == Binary.Operator.LeftShift || b.Oper == Binary.Operator.RightShift))
+ return this;
+
+ Convert.Error_CannotImplicitConversion (loc, a.original_source.Type, target_type);
return null;
+ }
}
- if (target.ExprClass != ExprClass.Variable){
- Report.Error (131, l,
- "Left hand of an assignment must be a variable, " +
- "a property or an indexer");
+ source = Convert.ImplicitConversionRequired (ec, source, target_type, loc);
+ if (source == null)
return null;
- }
+ // If we're an embedded assignment, we need to create a new temporary variable
+ // for the converted value. Our parent will use this new variable as its source.
+ // The same applies when we have an embedded assignment - in this case, we need
+ // to convert our embedded assignment's temporary local variable to the correct
+ // type and store it in a new temporary local.
+ if (is_embedded || embedded != null) {
+ type = target_type;
+ temp = new LocalTemporary (ec, type);
+ must_free_temp = true;
+ }
+
return this;
}
- void Emit (EmitContext ec, bool is_statement)
+ Expression EmitEmbedded (EmitContext ec)
{
- ILGenerator ig = ec.ig;
- ExprClass eclass = target.ExprClass;
+ // Emit an embedded assignment.
+
+ if (real_temp != null) {
+ // If we're the innermost assignment, `real_source' is the right-hand
+ // expression which gets assigned to all the variables left of it.
+ // Emit this expression and store its result in real_temp.
+ real_source.Emit (ec);
+ real_temp.Store (ec);
+ }
- //
- // Properties, Indexers and Arrays are of this kind
- // (Arrays because multi-dimensional arrays are manipulated
- // through calls that the runtime expands.
- //
- if (target is IAssignMethod){
- IAssignMethod am = (IAssignMethod) target;
+ if (embedded != null)
+ embedded.EmitEmbedded (ec);
- if (is_statement)
- am.EmitAssign (ec, source);
- else {
- LocalTemporary tempo;
-
- tempo = new LocalTemporary (ec, source.Type);
+ // This happens when we've done a type conversion, in this case source will be
+ // the expression which does the type conversion from real_temp.
+ // So emit it and store the result in temp; this is the var which will be read
+ // by our parent.
+ if (temp != real_temp) {
+ source.Emit (ec);
+ temp.Store (ec);
+ }
- source.Emit (ec);
- tempo.Store (ec);
- am.EmitAssign (ec, source);
- tempo.Emit (ec);
- }
- } else if (target is IStackStore) {
- //
- // If it is an instance field, load the this pointer
- //
- if (target is FieldExpr){
- FieldExpr fe = (FieldExpr) target;
-
- if (!fe.FieldInfo.IsStatic)
- ig.Emit (OpCodes.Ldarg_0);
- }
+ Expression temp_source = (temp != null) ? temp : source;
+ ((IAssignMethod) target).EmitAssign (ec, temp_source, false, false);
+ return temp_source;
+ }
- source.Emit (ec);
+ void ReleaseEmbedded (EmitContext ec)
+ {
+ if (embedded != null)
+ embedded.ReleaseEmbedded (ec);
+
+ if (real_temp != null)
+ real_temp.Release (ec);
+
+ if (must_free_temp)
+ temp.Release (ec);
+ }
+
+ void Emit (EmitContext ec, bool is_statement)
+ {
+ if (target is EventExpr) {
+ ((EventExpr) target).EmitAddOrRemove (ec, source);
+ return;
+ }
+
+ IAssignMethod am = (IAssignMethod) target;
- if (!is_statement)
- ig.Emit (OpCodes.Dup);
+ Expression temp_source;
+ if (embedded != null) {
+ temp_source = embedded.EmitEmbedded (ec);
- ((IStackStore) target).Store (ec);
- } else {
- Console.WriteLine ("Unhandled class: " + eclass + "\n Type:" + target);
+ if (temp != null) {
+ source.Emit (ec);
+ temp.Store (ec);
+ temp_source = temp;
+ }
+ } else
+ temp_source = source;
+
+ am.EmitAssign (ec, temp_source, !is_statement, this is CompoundAssign);
+
+ if (embedded != null) {
+ if (temp != null)
+ temp.Release (ec);
+ embedded.ReleaseEmbedded (ec);
}
}
Emit (ec, true);
}
}
+
+
+ //
+ // This class is used for compound assignments.
+ //
+ class CompoundAssign : Assign {
+ Binary.Operator op;
+ public Expression original_source;
+
+ public CompoundAssign (Binary.Operator op, Expression target, Expression source, Location l)
+ : base (target, source, l)
+ {
+ original_source = source;
+ this.op = op;
+ }
+
+ protected CompoundAssign (CompoundAssign embedded, Location l)
+ : this (embedded.op, embedded.target, embedded.source, l)
+ {
+ this.is_embedded = true;
+ }
+
+ protected override Assign GetEmbeddedAssign (Location loc)
+ {
+ return new CompoundAssign (this, loc);
+ }
+
+ public Expression ResolveSource (EmitContext ec)
+ {
+ return original_source.Resolve (ec);
+ }
+
+ public override Expression DoResolve (EmitContext ec)
+ {
+ original_source = original_source.Resolve (ec);
+ if (original_source == null)
+ return null;
+
+ target = target.Resolve (ec);
+ if (target == null)
+ return null;
+
+ //
+ // Only now we can decouple the original source/target
+ // into a tree, to guarantee that we do not have side
+ // effects.
+ //
+ source = new Binary (op, target, original_source, loc);
+ return base.DoResolve (ec);
+ }
+ }
}
projects / mono.git / blobdiff