//
// Author:
// Miguel de Icaza (miguel@ximian.com)
-// Martin Baulig (martin@gnome.org)
+// Martin Baulig (martin@ximian.com)
//
// (C) 2001, 2002, 2003 Ximian, Inc.
+// (C) 2004 Novell, Inc
//
using System;
using System.Reflection;
/// </remarks>
public interface IAssignMethod {
//
- // This method will emit the code for the actual assignment
+ // 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 EmitAssign (EmitContext ec, Expression source);
+ void Emit (EmitContext ec, bool leave_copy);
//
- // This method is invoked before any code generation takes
- // place, and it is a mechanism to inform that the expression
- // will be invoked more than once, and that the method should
- // use temporary values to avoid having side effects
+ // 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.
//
- // Example: a [ g () ] ++
- //
- void CacheTemporaries (EmitContext ec);
+ 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.
+ */
}
/// <summary>
/// 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;
-
- public LocalTemporary (EmitContext ec, Type t)
+ bool is_address;
+
+ public LocalTemporary (Type t) : this (t, false) {}
+
+ public LocalTemporary (Type t, bool is_address)
{
type = t;
eclass = ExprClass.Value;
- loc = Location.Null;
- builder = ec.GetTemporaryStorage (t);
+ this.is_address = is_address;
}
- public void Release (EmitContext ec)
- {
- ec.FreeTemporaryStorage (builder);
- builder = null;
- }
-
public LocalTemporary (LocalBuilder b, Type t)
{
type = 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;
+ if (builder == null)
+ builder = ec.GetTemporaryLocal (is_address ? TypeManager.GetReferenceType (type): type);
+
+ ig.Emit (OpCodes.Stloc, builder);
}
public void AddressOf (EmitContext ec, AddressOp mode)
{
- ec.ig.Emit (OpCodes.Ldloca, builder);
+ if (builder == null)
+ builder = ec.GetTemporaryLocal (is_address ? TypeManager.GetReferenceType (type): type);
+
+ // 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;
+ }
}
}
/// <summary>
/// The Assign node takes care of assigning the value of source into
- /// the expression represented by target.
+ /// the expression represented by target.
/// </summary>
public class Assign : ExpressionStatement {
protected Expression target, source, real_source;
protected bool is_embedded = false;
protected bool must_free_temp = false;
+ public Assign (Expression target, Expression source)
+ : this (target, source, target.Location)
+ {
+ }
+
public Assign (Expression target, Expression source, Location l)
{
this.target = 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 + "')");
+ Report.Error (70, l, "The event `" + TypeManager.CSharpSignature (ei) +
+ "' can only appear on the left hand side of += or -= (except when" +
+ " used from within the type `" + ei.DeclaringType + "')");
}
//
source = embedded = ((Assign) source).GetEmbeddedAssign (loc);
real_source = source = source.Resolve (ec);
- if (source == null)
+ 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.
if (embedded == null) {
if (this is CompoundAssign)
- real_temp = temp = new LocalTemporary (ec, target.Type);
+ real_temp = temp = new LocalTemporary (target.Type);
else
- real_temp = temp = new LocalTemporary (ec, source.Type);
+ real_temp = temp = new LocalTemporary (source.Type);
} else
temp = embedded.temp;
if (embedded != null)
source = (embedded.temp != null) ? embedded.temp : embedded.source;
- target = target.ResolveLValue (ec, source);
+ target = target.ResolveLValue (ec, source, Location);
if (target == null)
return null;
+ bool same_assignment = (embedded != null) ? embedded.Target.Equals(target) : source.Equals (target);
+ if (same_assignment) {
+ 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 = real_source.Type;
EventInfo ei = ((EventExpr) target).EventInfo;
Expression ml = MemberLookup (
- ec, ec.ContainerType, ei.Name,
+ ec.ContainerType, ec.ContainerType, ei.Name,
MemberTypes.Event, AllBindingFlags | BindingFlags.DeclaredOnly, loc);
if (ml == null) {
- //
- // If this is the case, then the Event does not belong
+ //
+ // 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
// in the case it is being referenced within the same type container;
// it will appear as a FieldExpr in that case.
//
-
- if (!(source is Binary)) {
+
+ if (!(source is BinaryDelegate)) {
error70 (ei, loc);
return null;
- } else {
- Binary tmp = ((Binary) source);
- if (tmp.Oper != Binary.Operator.Addition &&
- tmp.Oper != Binary.Operator.Subtraction) {
- error70 (ei, loc);
- return null;
- }
}
}
}
-
- 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;
- }
- if (target.eclass != ExprClass.Variable && target.eclass != ExprClass.EventAccess &&
- target.eclass != ExprClass.IndexerAccess && target.eclass != ExprClass.PropertyAccess){
+ 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");
}
if ((source.eclass == ExprClass.Type) && (source is TypeExpr)) {
- source.Error_UnexpectedKind ("variable or value");
+ source.Error_UnexpectedKind (ec.DeclContainer, "variable or value", loc);
return null;
- } else if (source is MethodGroupExpr){
+ } else if ((RootContext.Version == LanguageVersion.ISO_1) &&
+ (source is MethodGroupExpr)){
((MethodGroupExpr) source).ReportUsageError ();
return null;
+
}
- if (target_type == source_type)
+ 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
+ // If this assignment/operator was part of a compound binary
// operator, then we allow an explicit conversion, as detailed
- // in the spec.
+ // in the spec.
//
if (this is CompoundAssign){
CompoundAssign a = (CompoundAssign) this;
-
+
Binary b = source as Binary;
- if (b != null && b.IsBuiltinOperator){
+ 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);
+ a.original_source.Error_ValueCannotBeConverted (loc, target_type, true);
return null;
}
-
+
//
// 2. and the original right side is implicitly convertible to
- // the type of target_type.
+ // the type of target
//
if (Convert.ImplicitStandardConversionExists (a.original_source, target_type))
return this;
- Convert.Error_CannotImplicitConversion (loc, a.original_source.Type, target_type);
+ //
+ // 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;
+
+ a.original_source.Error_ValueCannotBeConverted (loc, target_type, false);
return null;
}
}
-
+
+ if (source.eclass == ExprClass.MethodGroup && !TypeManager.IsDelegateType (target_type)) {
+ Report.Error (428, source.Location, "Cannot convert method group `{0}' to non-delegate type `{1}'. Did you intend to invoke the method?",
+ ((MethodGroupExpr)source).Name, target.GetSignatureForError ());
+ return null;
+ }
+
source = Convert.ImplicitConversionRequired (ec, source, target_type, loc);
if (source == null)
return null;
// type and store it in a new temporary local.
if (is_embedded || embedded != null) {
type = target_type;
- temp = new LocalTemporary (ec, type);
+ temp = new LocalTemporary (type);
must_free_temp = true;
}
-
+
return this;
}
}
Expression temp_source = (temp != null) ? temp : source;
- ((IAssignMethod) target).EmitAssign (ec, temp_source);
+ ((IAssignMethod) target).EmitAssign (ec, temp_source, false, false);
return temp_source;
}
return;
}
- bool use_temporaries = false;
-
- //
- // FIXME! We need a way to "probe" if the process can
- // just use `dup' to propagate the result
- //
IAssignMethod am = (IAssignMethod) target;
-
- if (this is CompoundAssign){
- am.CacheTemporaries (ec);
- use_temporaries = true;
- }
-
- if (!is_statement)
- use_temporaries = true;
Expression temp_source;
if (embedded != null) {
} else
temp_source = source;
- if (use_temporaries){
- //
- // Doing this for every path is too expensive
- // I wonder if we can work around this and have a less
- // expensive path
- //
- LocalTemporary tempo;
-
- tempo = new LocalTemporary (ec, source.Type);
-
- temp_source.Emit (ec);
- tempo.Store (ec);
- am.EmitAssign (ec, tempo);
- if (!is_statement)
- tempo.Emit (ec);
-
- tempo.Release (ec);
- } else {
- am.EmitAssign (ec, temp_source);
- }
-
+ am.EmitAssign (ec, temp_source, !is_statement, this is CompoundAssign);
+
if (embedded != null) {
if (temp != null)
temp.Release (ec);
embedded.ReleaseEmbedded (ec);
}
}
-
+
public override void Emit (EmitContext ec)
{
Emit (ec, false);
}
}
-
+
//
- // This class is used for compound assignments.
+ // 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)
+
+ public CompoundAssign (Binary.Operator op, Expression target, Expression source)
+ : base (target, source, target.Location)
{
original_source = source;
this.op = op;
}
protected CompoundAssign (CompoundAssign embedded, Location l)
- : this (embedded.op, embedded.target, embedded.source, l)
+ : this (embedded.op, embedded.target, embedded.source)
{
this.is_embedded = true;
}
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);
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);
+ source = new Binary (op, target, original_source);
return base.DoResolve (ec);
}
}
}
-
-
-
-
projects / mono.git / blobdiff