// 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'
// 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); ->
[...] ->
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.
*/
}
/// 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.
+ /// 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
public class LocalTemporary : Expression, IMemoryLocation {
LocalBuilder builder;
bool is_address;
-
- public LocalTemporary (EmitContext ec, Type t) : this (ec, t, false) {}
-
- 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.GetTemporaryLocal (is_address ? TypeManager.GetReferenceType (t): t);
this.is_address = is_address;
}
ec.FreeTemporaryLocal (builder, type);
builder = null;
}
-
+
public override Expression DoResolve (EmitContext ec)
{
return this;
public override void Emit (EmitContext ec)
{
ILGenerator ig = ec.ig;
-
+
ig.Emit (OpCodes.Ldloc, builder);
// we need to copy from the pointer
if (is_address)
public void Store (EmitContext ec)
{
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)
{
+ 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
/// <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;
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 (target == null)
return null;
- if (source.Equals (target)) {
+ 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;
eclass = ExprClass.Value;
-
if (target is EventExpr) {
EventInfo ei = ((EventExpr) target).EventInfo;
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 BinaryDelegate)) {
error70 (ei, loc);
return null;
- }
+ }
}
}
-
+
if (!(target is IAssignMethod) && (target.eclass != ExprClass.EventAccess)) {
Report.Error (131, loc,
"Left hand of an assignment must be a variable, " +
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 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){
//
// 1. if the source is explicitly convertible to the
// target_type
//
-
+
source = Convert.ExplicitConversion (ec, source, target_type, loc);
if (source == null){
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
}
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;
}
((EventExpr) target).EmitAddOrRemove (ec, source);
return;
}
-
+
IAssignMethod am = (IAssignMethod) target;
Expression temp_source;
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);
}
}
-
+
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)
: base (target, source, target.Location)
{
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
}
}
}
-
-
-
-
projects / mono.git / blobdiff