//
// statement.cs: Statement representation for the IL tree.
//
// Author:
// Miguel de Icaza (miguel@ximian.com)
//
// (C) 2001, 2002 Ximian, Inc.
//
using System;
using System.Reflection;
using System.Reflection.Emit;
using System.Diagnostics;
namespace Mono.CSharp {
using System.Collections;
public abstract class Statement {
public Location loc;
///
/// Resolves the statement, true means that all sub-statements
/// did resolve ok.
//
public virtual bool Resolve (EmitContext ec)
{
return true;
}
///
/// Return value indicates whether all code paths emitted return.
///
public abstract bool Emit (EmitContext ec);
public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
{
e = e.Resolve (ec);
if (e == null)
return null;
if (e.Type != TypeManager.bool_type){
e = Expression.ConvertImplicit (ec, e, TypeManager.bool_type,
new Location (-1));
}
if (e == null){
Report.Error (
31, loc, "Can not convert the expression to a boolean");
}
if (CodeGen.SymbolWriter != null)
ec.Mark (loc);
return e;
}
///
/// Emits a bool expression.
///
public static void EmitBoolExpression (EmitContext ec, Expression bool_expr,
Label target, bool isTrue)
{
ILGenerator ig = ec.ig;
bool invert = false;
if (bool_expr is Unary){
Unary u = (Unary) bool_expr;
if (u.Oper == Unary.Operator.LogicalNot){
invert = true;
u.EmitLogicalNot (ec);
}
}
if (!invert)
bool_expr.Emit (ec);
if (isTrue){
if (invert)
ig.Emit (OpCodes.Brfalse, target);
else
ig.Emit (OpCodes.Brtrue, target);
} else {
if (invert)
ig.Emit (OpCodes.Brtrue, target);
else
ig.Emit (OpCodes.Brfalse, target);
}
}
public static void Warning_DeadCodeFound (Location loc)
{
Report.Warning (162, loc, "Unreachable code detected");
}
}
public class EmptyStatement : Statement {
public override bool Resolve (EmitContext ec)
{
return true;
}
public override bool Emit (EmitContext ec)
{
return false;
}
}
public class If : Statement {
Expression expr;
public Statement TrueStatement;
public Statement FalseStatement;
public If (Expression expr, Statement trueStatement, Location l)
{
this.expr = expr;
TrueStatement = trueStatement;
loc = l;
}
public If (Expression expr,
Statement trueStatement,
Statement falseStatement,
Location l)
{
this.expr = expr;
TrueStatement = trueStatement;
FalseStatement = falseStatement;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
expr = ResolveBoolean (ec, expr, loc);
if (expr == null){
return false;
}
if (TrueStatement.Resolve (ec)){
if (FalseStatement != null){
if (FalseStatement.Resolve (ec))
return true;
return false;
}
return true;
}
return false;
}
public override bool Emit (EmitContext ec)
{
ILGenerator ig = ec.ig;
Label false_target = ig.DefineLabel ();
Label end;
bool is_true_ret, is_false_ret;
//
// Dead code elimination
//
if (expr is BoolConstant){
bool take = ((BoolConstant) expr).Value;
if (take){
if (FalseStatement != null){
Warning_DeadCodeFound (FalseStatement.loc);
}
return TrueStatement.Emit (ec);
} else {
Warning_DeadCodeFound (TrueStatement.loc);
if (FalseStatement != null)
return FalseStatement.Emit (ec);
}
}
EmitBoolExpression (ec, expr, false_target, false);
is_true_ret = TrueStatement.Emit (ec);
is_false_ret = is_true_ret;
if (FalseStatement != null){
bool branch_emitted = false;
end = ig.DefineLabel ();
if (!is_true_ret){
ig.Emit (OpCodes.Br, end);
branch_emitted = true;
}
ig.MarkLabel (false_target);
is_false_ret = FalseStatement.Emit (ec);
if (branch_emitted)
ig.MarkLabel (end);
} else {
ig.MarkLabel (false_target);
is_false_ret = false;
}
return is_true_ret && is_false_ret;
}
}
public class Do : Statement {
public Expression expr;
public readonly Statement EmbeddedStatement;
public Do (Statement statement, Expression boolExpr, Location l)
{
expr = boolExpr;
EmbeddedStatement = statement;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
expr = ResolveBoolean (ec, expr, loc);
if (expr == null)
return false;
return EmbeddedStatement.Resolve (ec);
}
public override bool Emit (EmitContext ec)
{
ILGenerator ig = ec.ig;
Label loop = ig.DefineLabel ();
Label old_begin = ec.LoopBegin;
Label old_end = ec.LoopEnd;
bool old_inloop = ec.InLoop;
ec.LoopBegin = ig.DefineLabel ();
ec.LoopEnd = ig.DefineLabel ();
ec.InLoop = true;
ig.MarkLabel (loop);
EmbeddedStatement.Emit (ec);
ig.MarkLabel (ec.LoopBegin);
//
// Dead code elimination
//
if (expr is BoolConstant){
bool res = ((BoolConstant) expr).Value;
if (res)
ec.ig.Emit (OpCodes.Br, loop);
} else
EmitBoolExpression (ec, expr, loop, true);
ig.MarkLabel (ec.LoopEnd);
ec.LoopBegin = old_begin;
ec.LoopEnd = old_end;
ec.InLoop = old_inloop;
//
// Inform whether we are infinite or not
//
if (expr is BoolConstant){
BoolConstant bc = (BoolConstant) expr;
if (bc.Value == true)
return true;
}
return false;
}
}
public class While : Statement {
public Expression expr;
public readonly Statement Statement;
public While (Expression boolExpr, Statement statement, Location l)
{
this.expr = boolExpr;
Statement = statement;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
expr = ResolveBoolean (ec, expr, loc);
if (expr == null)
return false;
return Statement.Resolve (ec);
}
public override bool Emit (EmitContext ec)
{
ILGenerator ig = ec.ig;
Label old_begin = ec.LoopBegin;
Label old_end = ec.LoopEnd;
bool old_inloop = ec.InLoop;
Label while_loop = ig.DefineLabel ();
bool ret;
ec.LoopBegin = ig.DefineLabel ();
ec.LoopEnd = ig.DefineLabel ();
ec.InLoop = true;
ig.Emit (OpCodes.Br, ec.LoopBegin);
ig.MarkLabel (while_loop);
//
// Inform whether we are infinite or not
//
if (expr is BoolConstant){
BoolConstant bc = (BoolConstant) expr;
ig.MarkLabel (ec.LoopBegin);
if (bc.Value == false){
Warning_DeadCodeFound (Statement.loc);
ret = false;
} else {
Statement.Emit (ec);
ig.Emit (OpCodes.Br, ec.LoopBegin);
//
// Inform that we are infinite (ie, `we return')
//
ret = true;
}
ig.MarkLabel (ec.LoopEnd);
} else {
Statement.Emit (ec);
ig.MarkLabel (ec.LoopBegin);
EmitBoolExpression (ec, expr, while_loop, true);
ig.MarkLabel (ec.LoopEnd);
ret = false;
}
ec.LoopBegin = old_begin;
ec.LoopEnd = old_end;
ec.InLoop = old_inloop;
return ret;
}
}
public class For : Statement {
Expression Test;
readonly Statement InitStatement;
readonly Statement Increment;
readonly Statement Statement;
public For (Statement initStatement,
Expression test,
Statement increment,
Statement statement,
Location l)
{
InitStatement = initStatement;
Test = test;
Increment = increment;
Statement = statement;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
bool ok = true;
if (Test != null){
Test = ResolveBoolean (ec, Test, loc);
if (Test == null)
ok = false;
}
if (InitStatement != null){
if (!InitStatement.Resolve (ec))
ok = false;
}
if (Increment != null){
if (!Increment.Resolve (ec))
ok = false;
}
return Statement.Resolve (ec) && ok;
}
public override bool Emit (EmitContext ec)
{
ILGenerator ig = ec.ig;
Label old_begin = ec.LoopBegin;
Label old_end = ec.LoopEnd;
bool old_inloop = ec.InLoop;
Label loop = ig.DefineLabel ();
if (InitStatement != null)
if (! (InitStatement is EmptyStatement))
InitStatement.Emit (ec);
ec.LoopBegin = ig.DefineLabel ();
ec.LoopEnd = ig.DefineLabel ();
ec.InLoop = true;
ig.MarkLabel (loop);
//
// If test is null, there is no test, and we are just
// an infinite loop
//
if (Test != null)
EmitBoolExpression (ec, Test, ec.LoopEnd, false);
Statement.Emit (ec);
ig.MarkLabel (ec.LoopBegin);
if (!(Increment is EmptyStatement))
Increment.Emit (ec);
ig.Emit (OpCodes.Br, loop);
ig.MarkLabel (ec.LoopEnd);
ec.LoopBegin = old_begin;
ec.LoopEnd = old_end;
ec.InLoop = old_inloop;
//
// Inform whether we are infinite or not
//
if (Test != null){
if (Test is BoolConstant){
BoolConstant bc = (BoolConstant) Test;
if (bc.Value)
return true;
}
return false;
} else
return true;
}
}
public class StatementExpression : Statement {
Expression expr;
public StatementExpression (ExpressionStatement expr, Location l)
{
this.expr = expr;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
expr = (Expression) expr.Resolve (ec);
return expr != null;
}
public override bool Emit (EmitContext ec)
{
ILGenerator ig = ec.ig;
if (expr is ExpressionStatement)
((ExpressionStatement) expr).EmitStatement (ec);
else {
expr.Emit (ec);
ig.Emit (OpCodes.Pop);
}
return false;
}
public override string ToString ()
{
return "StatementExpression (" + expr + ")";
}
}
///
/// Implements the return statement
///
public class Return : Statement {
public Expression Expr;
public Return (Expression expr, Location l)
{
Expr = expr;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
if (Expr != null){
Expr = Expr.Resolve (ec);
if (Expr == null)
return false;
}
return true;
}
public override bool Emit (EmitContext ec)
{
if (ec.InFinally){
Report.Error (157,loc,"Control can not leave the body of the finally block");
return false;
}
if (ec.ReturnType == null){
if (Expr != null){
Report.Error (127, loc, "Return with a value not allowed here");
return false;
}
} else {
if (Expr == null){
Report.Error (126, loc, "An object of type `" +
TypeManager.CSharpName (ec.ReturnType) + "' is " +
"expected for the return statement");
return false;
}
if (Expr.Type != ec.ReturnType)
Expr = Expression.ConvertImplicitRequired (
ec, Expr, ec.ReturnType, loc);
if (Expr == null)
return false;
Expr.Emit (ec);
if (ec.InTry || ec.InCatch)
ec.ig.Emit (OpCodes.Stloc, ec.TemporaryReturn ());
}
if (ec.InTry || ec.InCatch)
ec.ig.Emit (OpCodes.Leave, ec.ReturnLabel);
else
ec.ig.Emit (OpCodes.Ret);
return true;
}
}
public class Goto : Statement {
string target;
Block block;
public override bool Resolve (EmitContext ec)
{
return true;
}
public Goto (Block parent_block, string label, Location l)
{
block = parent_block;
loc = l;
target = label;
}
public string Target {
get {
return target;
}
}
public override bool Emit (EmitContext ec)
{
LabeledStatement label = block.LookupLabel (target);
if (label == null){
//
// Maybe we should catch this before?
//
Report.Error (
159, loc,
"No such label `" + target + "' in this scope");
return false;
}
Label l = label.LabelTarget (ec);
ec.ig.Emit (OpCodes.Br, l);
return false;
}
}
public class LabeledStatement : Statement {
string label_name;
bool defined;
Label label;
public LabeledStatement (string label_name)
{
this.label_name = label_name;
}
public Label LabelTarget (EmitContext ec)
{
if (defined)
return label;
label = ec.ig.DefineLabel ();
defined = true;
return label;
}
public override bool Emit (EmitContext ec)
{
LabelTarget (ec);
ec.ig.MarkLabel (label);
return false;
}
}
///
/// `goto default' statement
///
public class GotoDefault : Statement {
public GotoDefault (Location l)
{
loc = l;
}
public override bool Emit (EmitContext ec)
{
if (ec.Switch == null){
Report.Error (153, loc, "goto default is only valid in a switch statement");
return false;
}
if (!ec.Switch.GotDefault){
Report.Error (159, loc, "No default target on switch statement");
return false;
}
ec.ig.Emit (OpCodes.Br, ec.Switch.DefaultTarget);
return false;
}
}
///
/// `goto case' statement
///
public class GotoCase : Statement {
Expression expr;
public GotoCase (Expression e, Location l)
{
expr = e;
loc = l;
}
public override bool Emit (EmitContext ec)
{
if (ec.Switch == null){
Report.Error (153, loc, "goto case is only valid in a switch statement");
return false;
}
expr = expr.Resolve (ec);
if (expr == null)
return false;
if (!(expr is Constant)){
Report.Error (159, loc, "Target expression for goto case is not constant");
return false;
}
object val = Expression.ConvertIntLiteral (
(Constant) expr, ec.Switch.SwitchType, loc);
if (val == null)
return false;
SwitchLabel sl = (SwitchLabel) ec.Switch.Elements [val];
if (sl == null){
Report.Error (
159, loc,
"No such label 'case " + val + "': for the goto case");
}
ec.ig.Emit (OpCodes.Br, sl.ILLabelCode);
return true;
}
}
public class Throw : Statement {
Expression expr;
public Throw (Expression expr, Location l)
{
this.expr = expr;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
if (expr != null){
expr = expr.Resolve (ec);
if (expr == null)
return false;
}
return true;
}
public override bool Emit (EmitContext ec)
{
if (expr == null){
if (ec.InCatch)
ec.ig.Emit (OpCodes.Rethrow);
else {
Report.Error (
156, loc,
"A throw statement with no argument is only " +
"allowed in a catch clause");
}
return false;
}
expr.Emit (ec);
ec.ig.Emit (OpCodes.Throw);
return true;
}
}
public class Break : Statement {
public Break (Location l)
{
loc = l;
}
public override bool Emit (EmitContext ec)
{
ILGenerator ig = ec.ig;
if (ec.InLoop == false && ec.Switch == null){
Report.Error (139, loc, "No enclosing loop or switch to continue to");
return false;
}
ig.Emit (OpCodes.Br, ec.LoopEnd);
return false;
}
}
public class Continue : Statement {
public Continue (Location l)
{
loc = l;
}
public override bool Emit (EmitContext ec)
{
Label begin = ec.LoopBegin;
if (!ec.InLoop){
Report.Error (139, loc, "No enclosing loop to continue to");
return false;
}
//
// UGH: Non trivial. This Br might cross a try/catch boundary
// How can we tell?
//
// while () {
// try { ... } catch { continue; }
// }
//
// From:
// try {} catch { while () { continue; }}
//
ec.ig.Emit (OpCodes.Br, begin);
return false;
}
}
public class VariableInfo {
public readonly string Type;
public LocalBuilder LocalBuilder;
public Type VariableType;
public readonly Location Location;
public bool Used;
public bool Assigned;
public bool ReadOnly;
public VariableInfo (string type, Location l)
{
Type = type;
LocalBuilder = null;
Location = l;
}
public void MakePinned ()
{
TypeManager.MakePinned (LocalBuilder);
}
}
///
/// Block represents a C# block.
///
///
///
/// This class is used in a number of places: either to represent
/// explicit blocks that the programmer places or implicit blocks.
///
/// Implicit blocks are used as labels or to introduce variable
/// declarations.
///
public class Block : Statement {
public readonly Block Parent;
public readonly bool Implicit;
public readonly Location StartLocation;
public Location EndLocation;
//
// The statements in this block
//
ArrayList statements;
//
// An array of Blocks. We keep track of children just
// to generate the local variable declarations.
//
// Statements and child statements are handled through the
// statements.
//
ArrayList children;
//
// Labels. (label, block) pairs.
//
Hashtable labels;
//
// Keeps track of (name, type) pairs
//
Hashtable variables;
//
// Keeps track of constants
Hashtable constants;
//
// Maps variable names to ILGenerator.LocalBuilders
//
Hashtable local_builders;
bool used = false;
static int id;
int this_id;
public Block (Block parent)
: this (parent, false, Location.Null, Location.Null)
{ }
public Block (Block parent, bool implicit_block)
: this (parent, implicit_block, Location.Null, Location.Null)
{ }
public Block (Block parent, Location start, Location end)
: this (parent, false, start, end)
{ }
public Block (Block parent, bool implicit_block, Location start, Location end)
{
if (parent != null)
parent.AddChild (this);
this.Parent = parent;
this.Implicit = implicit_block;
this.StartLocation = start;
this.EndLocation = end;
this.loc = start;
this_id = id++;
statements = new ArrayList ();
}
public int ID {
get {
return this_id;
}
}
void AddChild (Block b)
{
if (children == null)
children = new ArrayList ();
children.Add (b);
}
public void SetEndLocation (Location loc)
{
EndLocation = loc;
}
///
/// Adds a label to the current block.
///
///
///
/// false if the name already exists in this block. true
/// otherwise.
///
///
public bool AddLabel (string name, LabeledStatement target)
{
if (labels == null)
labels = new Hashtable ();
if (labels.Contains (name))
return false;
labels.Add (name, target);
return true;
}
public LabeledStatement LookupLabel (string name)
{
if (labels != null){
if (labels.Contains (name))
return ((LabeledStatement) labels [name]);
}
if (Parent != null)
return Parent.LookupLabel (name);
return null;
}
public VariableInfo AddVariable (string type, string name, Parameters pars, Location l)
{
if (variables == null)
variables = new Hashtable ();
if (GetVariableType (name) != null)
return null;
if (pars != null) {
int idx = 0;
Parameter p = pars.GetParameterByName (name, out idx);
if (p != null)
return null;
}
VariableInfo vi = new VariableInfo (type, l);
variables.Add (name, vi);
// Console.WriteLine ("Adding {0} to {1}", name, ID);
return vi;
}
public bool AddConstant (string type, string name, Expression value, Parameters pars, Location l)
{
if (AddVariable (type, name, pars, l) == null)
return false;
if (constants == null)
constants = new Hashtable ();
constants.Add (name, value);
return true;
}
public Hashtable Variables {
get {
return variables;
}
}
public VariableInfo GetVariableInfo (string name)
{
if (variables != null) {
object temp;
temp = variables [name];
if (temp != null){
return (VariableInfo) temp;
}
}
if (Parent != null)
return Parent.GetVariableInfo (name);
return null;
}
public string GetVariableType (string name)
{
VariableInfo vi = GetVariableInfo (name);
if (vi != null)
return vi.Type;
return null;
}
public Expression GetConstantExpression (string name)
{
if (constants != null) {
object temp;
temp = constants [name];
if (temp != null)
return (Expression) temp;
}
if (Parent != null)
return Parent.GetConstantExpression (name);
return null;
}
///
/// True if the variable named @name has been defined
/// in this block
///
public bool IsVariableDefined (string name)
{
// Console.WriteLine ("Looking up {0} in {1}", name, ID);
if (variables != null) {
if (variables.Contains (name))
return true;
}
if (Parent != null)
return Parent.IsVariableDefined (name);
return false;
}
///
/// True if the variable named @name is a constant
///
public bool IsConstant (string name)
{
Expression e = null;
e = GetConstantExpression (name);
return e != null;
}
///
/// Use to fetch the statement associated with this label
///
public Statement this [string name] {
get {
return (Statement) labels [name];
}
}
///
/// A list of labels that were not used within this block
///
public string [] GetUnreferenced ()
{
// FIXME: Implement me
return null;
}
public void AddStatement (Statement s)
{
statements.Add (s);
used = true;
}
public bool Used {
get {
return used;
}
}
public void Use ()
{
used = true;
}
///
/// Emits the variable declarations and labels.
///
///
/// tc: is our typecontainer (to resolve type references)
/// ig: is the code generator:
/// toplevel: the toplevel block. This is used for checking
/// that no two labels with the same name are used.
///
public void EmitMeta (EmitContext ec, Block toplevel)
{
DeclSpace ds = ec.DeclSpace;
ILGenerator ig = ec.ig;
//
// Process this block variables
//
if (variables != null){
local_builders = new Hashtable ();
foreach (DictionaryEntry de in variables){
string name = (string) de.Key;
VariableInfo vi = (VariableInfo) de.Value;
Type t;
t = RootContext.LookupType (ds, vi.Type, false, vi.Location);
if (t == null)
continue;
vi.VariableType = t;
vi.LocalBuilder = ig.DeclareLocal (t);
if (CodeGen.SymbolWriter != null)
vi.LocalBuilder.SetLocalSymInfo (name);
if (constants == null)
continue;
Expression cv = (Expression) constants [name];
if (cv == null)
continue;
Expression e = cv.Resolve (ec);
if (e == null)
continue;
if (!(e is Constant)){
Report.Error (133, vi.Location,
"The expression being assigned to `" +
name + "' must be constant (" + e + ")");
continue;
}
constants.Remove (name);
constants.Add (name, e);
}
}
//
// Now, handle the children
//
if (children != null){
foreach (Block b in children)
b.EmitMeta (ec, toplevel);
}
}
public void UsageWarning ()
{
string name;
if (variables != null){
foreach (DictionaryEntry de in variables){
VariableInfo vi = (VariableInfo) de.Value;
if (vi.Used)
continue;
name = (string) de.Key;
if (vi.Assigned){
Report.Warning (
219, vi.Location, "The variable `" + name +
"' is assigned but its value is never used");
} else {
Report.Warning (
168, vi.Location, "The variable `" +
name +
"' is declared but never used");
}
}
}
if (children != null)
foreach (Block b in children)
b.UsageWarning ();
}
public override bool Resolve (EmitContext ec)
{
Block prev_block = ec.CurrentBlock;
ec.CurrentBlock = this;
foreach (Statement s in statements){
if (s.Resolve (ec) == false){
ec.CurrentBlock = prev_block;
return false;
}
}
ec.CurrentBlock = prev_block;
return true;
}
public override bool Emit (EmitContext ec)
{
bool is_ret = false;
Block prev_block = ec.CurrentBlock;
ec.CurrentBlock = this;
if (CodeGen.SymbolWriter != null) {
ec.Mark (StartLocation);
foreach (Statement s in statements) {
ec.Mark (s.loc);
is_ret = s.Emit (ec);
}
ec.Mark (EndLocation);
} else {
foreach (Statement s in statements)
is_ret = s.Emit (ec);
}
ec.CurrentBlock = prev_block;
return is_ret;
}
}
public class SwitchLabel {
Expression label;
object converted;
public Location loc;
public Label ILLabel;
public Label ILLabelCode;
//
// if expr == null, then it is the default case.
//
public SwitchLabel (Expression expr, Location l)
{
label = expr;
loc = l;
}
public Expression Label {
get {
return label;
}
}
public object Converted {
get {
return converted;
}
}
//
// Resolves the expression, reduces it to a literal if possible
// and then converts it to the requested type.
//
public bool ResolveAndReduce (EmitContext ec, Type required_type)
{
ILLabel = ec.ig.DefineLabel ();
ILLabelCode = ec.ig.DefineLabel ();
if (label == null)
return true;
Expression e = label.Resolve (ec);
if (e == null)
return false;
if (!(e is Constant)){
Console.WriteLine ("Value is: " + label);
Report.Error (150, loc, "A constant value is expected");
return false;
}
if (e is StringConstant || e is NullLiteral){
if (required_type == TypeManager.string_type){
converted = label;
ILLabel = ec.ig.DefineLabel ();
return true;
}
}
converted = Expression.ConvertIntLiteral ((Constant) e, required_type, loc);
if (converted == null)
return false;
return true;
}
}
public class SwitchSection {
// An array of SwitchLabels.
public readonly ArrayList Labels;
public readonly Block Block;
public SwitchSection (ArrayList labels, Block block)
{
Labels = labels;
Block = block;
}
}
public class Switch : Statement {
public readonly ArrayList Sections;
public Expression Expr;
///
/// Maps constants whose type type SwitchType to their SwitchLabels.
///
public Hashtable Elements;
///
/// The governing switch type
///
public Type SwitchType;
//
// Computed
//
bool got_default;
Label default_target;
//
// The types allowed to be implicitly cast from
// on the governing type
//
static Type [] allowed_types;
public Switch (Expression e, ArrayList sects, Location l)
{
Expr = e;
Sections = sects;
loc = l;
}
public bool GotDefault {
get {
return got_default;
}
}
public Label DefaultTarget {
get {
return default_target;
}
}
//
// Determines the governing type for a switch. The returned
// expression might be the expression from the switch, or an
// expression that includes any potential conversions to the
// integral types or to string.
//
Expression SwitchGoverningType (EmitContext ec, Type t)
{
if (t == TypeManager.int32_type ||
t == TypeManager.uint32_type ||
t == TypeManager.char_type ||
t == TypeManager.byte_type ||
t == TypeManager.sbyte_type ||
t == TypeManager.ushort_type ||
t == TypeManager.short_type ||
t == TypeManager.uint64_type ||
t == TypeManager.int64_type ||
t == TypeManager.string_type ||
t == TypeManager.bool_type ||
t.IsSubclassOf (TypeManager.enum_type))
return Expr;
if (allowed_types == null){
allowed_types = new Type [] {
TypeManager.sbyte_type,
TypeManager.byte_type,
TypeManager.short_type,
TypeManager.ushort_type,
TypeManager.int32_type,
TypeManager.uint32_type,
TypeManager.int64_type,
TypeManager.uint64_type,
TypeManager.char_type,
TypeManager.bool_type,
TypeManager.string_type
};
}
//
// Try to find a *user* defined implicit conversion.
//
// If there is no implicit conversion, or if there are multiple
// conversions, we have to report an error
//
Expression converted = null;
foreach (Type tt in allowed_types){
Expression e;
e = Expression.ImplicitUserConversion (ec, Expr, tt, loc);
if (e == null)
continue;
if (converted != null){
Report.Error (-12, loc, "More than one conversion to an integral " +
" type exists for type `" +
TypeManager.CSharpName (Expr.Type)+"'");
return null;
} else
converted = e;
}
return converted;
}
void error152 (string n)
{
Report.Error (
152, "The label `" + n + ":' " +
"is already present on this switch statement");
}
//
// Performs the basic sanity checks on the switch statement
// (looks for duplicate keys and non-constant expressions).
//
// It also returns a hashtable with the keys that we will later
// use to compute the switch tables
//
bool CheckSwitch (EmitContext ec)
{
Type compare_type;
bool error = false;
Elements = new Hashtable ();
got_default = false;
if (TypeManager.IsEnumType (SwitchType)){
compare_type = TypeManager.EnumToUnderlying (SwitchType);
} else
compare_type = SwitchType;
foreach (SwitchSection ss in Sections){
foreach (SwitchLabel sl in ss.Labels){
if (!sl.ResolveAndReduce (ec, SwitchType)){
error = true;
continue;
}
if (sl.Label == null){
if (got_default){
error152 ("default");
error = true;
}
got_default = true;
continue;
}
object key = sl.Converted;
if (key is Constant)
key = ((Constant) key).GetValue ();
if (key == null)
key = NullLiteral.Null;
string lname = null;
if (compare_type == TypeManager.uint64_type){
ulong v = (ulong) key;
if (Elements.Contains (v))
lname = v.ToString ();
else
Elements.Add (v, sl);
} else if (compare_type == TypeManager.int64_type){
long v = (long) key;
if (Elements.Contains (v))
lname = v.ToString ();
else
Elements.Add (v, sl);
} else if (compare_type == TypeManager.uint32_type){
uint v = (uint) key;
if (Elements.Contains (v))
lname = v.ToString ();
else
Elements.Add (v, sl);
} else if (compare_type == TypeManager.char_type){
char v = (char) key;
if (Elements.Contains (v))
lname = v.ToString ();
else
Elements.Add (v, sl);
} else if (compare_type == TypeManager.byte_type){
byte v = (byte) key;
if (Elements.Contains (v))
lname = v.ToString ();
else
Elements.Add (v, sl);
} else if (compare_type == TypeManager.sbyte_type){
sbyte v = (sbyte) key;
if (Elements.Contains (v))
lname = v.ToString ();
else
Elements.Add (v, sl);
} else if (compare_type == TypeManager.short_type){
short v = (short) key;
if (Elements.Contains (v))
lname = v.ToString ();
else
Elements.Add (v, sl);
} else if (compare_type == TypeManager.ushort_type){
ushort v = (ushort) key;
if (Elements.Contains (v))
lname = v.ToString ();
else
Elements.Add (v, sl);
} else if (compare_type == TypeManager.string_type){
if (key is NullLiteral){
if (Elements.Contains (NullLiteral.Null))
lname = "null";
else
Elements.Add (NullLiteral.Null, null);
} else {
string s = (string) key;
if (Elements.Contains (s))
lname = s;
else
Elements.Add (s, sl);
}
} else if (compare_type == TypeManager.int32_type) {
int v = (int) key;
if (Elements.Contains (v))
lname = v.ToString ();
else
Elements.Add (v, sl);
} else if (compare_type == TypeManager.bool_type) {
bool v = (bool) key;
if (Elements.Contains (v))
lname = v.ToString ();
else
Elements.Add (v, sl);
}
else
{
throw new Exception ("Unknown switch type!" +
SwitchType + " " + compare_type);
}
if (lname != null){
error152 ("case + " + lname);
error = true;
}
}
}
if (error)
return false;
return true;
}
void EmitObjectInteger (ILGenerator ig, object k)
{
if (k is int)
IntConstant.EmitInt (ig, (int) k);
else if (k is Constant) {
EmitObjectInteger (ig, ((Constant) k).GetValue ());
}
else if (k is uint)
IntConstant.EmitInt (ig, unchecked ((int) (uint) k));
else if (k is long)
{
if ((long) k >= int.MinValue && (long) k <= int.MaxValue)
{
IntConstant.EmitInt (ig, (int) (long) k);
ig.Emit (OpCodes.Conv_I8);
}
else
LongConstant.EmitLong (ig, (long) k);
}
else if (k is ulong)
{
if ((ulong) k < (1L<<32))
{
IntConstant.EmitInt (ig, (int) (long) k);
ig.Emit (OpCodes.Conv_U8);
}
else
{
LongConstant.EmitLong (ig, unchecked ((long) (ulong) k));
}
}
else if (k is char)
IntConstant.EmitInt (ig, (int) ((char) k));
else if (k is sbyte)
IntConstant.EmitInt (ig, (int) ((sbyte) k));
else if (k is byte)
IntConstant.EmitInt (ig, (int) ((byte) k));
else if (k is short)
IntConstant.EmitInt (ig, (int) ((short) k));
else if (k is ushort)
IntConstant.EmitInt (ig, (int) ((ushort) k));
else if (k is bool)
IntConstant.EmitInt (ig, ((bool) k) ? 1 : 0);
else
throw new Exception ("Unhandled case");
}
// structure used to hold blocks of keys while calculating table switch
class KeyBlock : IComparable
{
public KeyBlock (long _nFirst)
{
nFirst = nLast = _nFirst;
}
public long nFirst;
public long nLast;
public ArrayList rgKeys = null;
public int Length
{
get { return (int) (nLast - nFirst + 1); }
}
public static long TotalLength (KeyBlock kbFirst, KeyBlock kbLast)
{
return kbLast.nLast - kbFirst.nFirst + 1;
}
public int CompareTo (object obj)
{
KeyBlock kb = (KeyBlock) obj;
int nLength = Length;
int nLengthOther = kb.Length;
if (nLengthOther == nLength)
return (int) (kb.nFirst - nFirst);
return nLength - nLengthOther;
}
}
///
/// This method emits code for a lookup-based switch statement (non-string)
/// Basically it groups the cases into blocks that are at least half full,
/// and then spits out individual lookup opcodes for each block.
/// It emits the longest blocks first, and short blocks are just
/// handled with direct compares.
///
///
///
///
bool TableSwitchEmit (EmitContext ec, LocalBuilder val)
{
int cElements = Elements.Count;
object [] rgKeys = new object [cElements];
Elements.Keys.CopyTo (rgKeys, 0);
Array.Sort (rgKeys);
// initialize the block list with one element per key
ArrayList rgKeyBlocks = new ArrayList ();
foreach (object key in rgKeys)
rgKeyBlocks.Add (new KeyBlock (Convert.ToInt64 (key)));
KeyBlock kbCurr;
// iteratively merge the blocks while they are at least half full
// there's probably a really cool way to do this with a tree...
while (rgKeyBlocks.Count > 1)
{
ArrayList rgKeyBlocksNew = new ArrayList ();
kbCurr = (KeyBlock) rgKeyBlocks [0];
for (int ikb = 1; ikb < rgKeyBlocks.Count; ikb++)
{
KeyBlock kb = (KeyBlock) rgKeyBlocks [ikb];
if ((kbCurr.Length + kb.Length) * 2 >= KeyBlock.TotalLength (kbCurr, kb))
{
// merge blocks
kbCurr.nLast = kb.nLast;
}
else
{
// start a new block
rgKeyBlocksNew.Add (kbCurr);
kbCurr = kb;
}
}
rgKeyBlocksNew.Add (kbCurr);
if (rgKeyBlocks.Count == rgKeyBlocksNew.Count)
break;
rgKeyBlocks = rgKeyBlocksNew;
}
// initialize the key lists
foreach (KeyBlock kb in rgKeyBlocks)
kb.rgKeys = new ArrayList ();
// fill the key lists
int iBlockCurr = 0;
kbCurr = (KeyBlock) rgKeyBlocks [0];
foreach (object key in rgKeys)
{
bool fNextBlock = (key is UInt64) ? (ulong) key > (ulong) kbCurr.nLast : Convert.ToInt64 (key) > kbCurr.nLast;
if (fNextBlock)
kbCurr = (KeyBlock) rgKeyBlocks [++iBlockCurr];
kbCurr.rgKeys.Add (key);
}
// sort the blocks so we can tackle the largest ones first
rgKeyBlocks.Sort ();
// okay now we can start...
ILGenerator ig = ec.ig;
Label lblEnd = ig.DefineLabel (); // at the end ;-)
Label lblDefault = new Label ();
Type typeKeys = rgKeys [0].GetType (); // used for conversions
for (int iBlock = rgKeyBlocks.Count - 1; iBlock >= 0; --iBlock)
{
KeyBlock kb = ((KeyBlock) rgKeyBlocks [iBlock]);
lblDefault = (iBlock == 0) ? DefaultTarget : ig.DefineLabel ();
if (kb.Length <= 2)
{
foreach (object key in kb.rgKeys)
{
ig.Emit (OpCodes.Ldloc, val);
EmitObjectInteger (ig, key);
SwitchLabel sl = (SwitchLabel) Elements [key];
ig.Emit (OpCodes.Beq, sl.ILLabel);
}
}
else
{
// TODO: if all the keys in the block are the same and there are
// no gaps/defaults then just use a range-check.
if (SwitchType == TypeManager.int64_type ||
SwitchType == TypeManager.uint64_type)
{
// TODO: optimize constant/I4 cases
// check block range (could be > 2^31)
ig.Emit (OpCodes.Ldloc, val);
EmitObjectInteger (ig, Convert.ChangeType (kb.nFirst, typeKeys));
ig.Emit (OpCodes.Blt, lblDefault);
ig.Emit (OpCodes.Ldloc, val);
EmitObjectInteger (ig, Convert.ChangeType (kb.nFirst, typeKeys));
ig.Emit (OpCodes.Bgt, lblDefault);
// normalize range
ig.Emit (OpCodes.Ldloc, val);
if (kb.nFirst != 0)
{
EmitObjectInteger (ig, Convert.ChangeType (kb.nFirst, typeKeys));
ig.Emit (OpCodes.Sub);
}
ig.Emit (OpCodes.Conv_I4); // assumes < 2^31 labels!
}
else
{
// normalize range
ig.Emit (OpCodes.Ldloc, val);
int nFirst = (int) kb.nFirst;
if (nFirst > 0)
{
IntConstant.EmitInt (ig, nFirst);
ig.Emit (OpCodes.Sub);
}
else if (nFirst < 0)
{
IntConstant.EmitInt (ig, -nFirst);
ig.Emit (OpCodes.Add);
}
}
// first, build the list of labels for the switch
int iKey = 0;
int cJumps = kb.Length;
Label [] rgLabels = new Label [cJumps];
for (int iJump = 0; iJump < cJumps; iJump++)
{
object key = kb.rgKeys [iKey];
if (Convert.ToInt64 (key) == kb.nFirst + iJump)
{
SwitchLabel sl = (SwitchLabel) Elements [key];
rgLabels [iJump] = sl.ILLabel;
iKey++;
}
else
rgLabels [iJump] = lblDefault;
}
// emit the switch opcode
ig.Emit (OpCodes.Switch, rgLabels);
}
// mark the default for this block
if (iBlock != 0)
ig.MarkLabel (lblDefault);
}
// TODO: find the default case and emit it here,
// to prevent having to do the following jump.
// make sure to mark other labels in the default section
// the last default just goes to the end
ig.Emit (OpCodes.Br, lblDefault);
// now emit the code for the sections
bool fFoundDefault = false;
bool fAllReturn = true;
foreach (SwitchSection ss in Sections)
{
foreach (SwitchLabel sl in ss.Labels)
{
ig.MarkLabel (sl.ILLabel);
ig.MarkLabel (sl.ILLabelCode);
if (sl.Label == null)
{
ig.MarkLabel (lblDefault);
fFoundDefault = true;
}
}
fAllReturn &= ss.Block.Emit (ec);
//ig.Emit (OpCodes.Br, lblEnd);
}
if (!fFoundDefault)
ig.MarkLabel (lblDefault);
ig.MarkLabel (lblEnd);
return fAllReturn;
}
//
// This simple emit switch works, but does not take advantage of the
// `switch' opcode.
// TODO: remove non-string logic from here
// TODO: binary search strings?
//
bool SimpleSwitchEmit (EmitContext ec, LocalBuilder val)
{
ILGenerator ig = ec.ig;
Label end_of_switch = ig.DefineLabel ();
Label next_test = ig.DefineLabel ();
Label null_target = ig.DefineLabel ();
bool default_found = false;
bool first_test = true;
bool pending_goto_end = false;
bool all_return = true;
bool is_string = false;
bool null_found;
//
// Special processing for strings: we cant compare
// against null.
//
if (SwitchType == TypeManager.string_type){
ig.Emit (OpCodes.Ldloc, val);
is_string = true;
if (Elements.Contains (NullLiteral.Null)){
ig.Emit (OpCodes.Brfalse, null_target);
} else
ig.Emit (OpCodes.Brfalse, default_target);
ig.Emit (OpCodes.Ldloc, val);
ig.Emit (OpCodes.Call, TypeManager.string_isinterneted_string);
ig.Emit (OpCodes.Stloc, val);
}
SwitchSection last_section;
last_section = (SwitchSection) Sections [Sections.Count-1];
foreach (SwitchSection ss in Sections){
Label sec_begin = ig.DefineLabel ();
if (pending_goto_end)
ig.Emit (OpCodes.Br, end_of_switch);
int label_count = ss.Labels.Count;
null_found = false;
foreach (SwitchLabel sl in ss.Labels){
ig.MarkLabel (sl.ILLabel);
if (!first_test){
ig.MarkLabel (next_test);
next_test = ig.DefineLabel ();
}
//
// If we are the default target
//
if (sl.Label == null){
ig.MarkLabel (default_target);
default_found = true;
} else {
object lit = sl.Converted;
if (lit is NullLiteral){
null_found = true;
if (label_count == 1)
ig.Emit (OpCodes.Br, next_test);
continue;
}
if (is_string){
StringConstant str = (StringConstant) lit;
ig.Emit (OpCodes.Ldloc, val);
ig.Emit (OpCodes.Ldstr, str.Value);
if (label_count == 1)
ig.Emit (OpCodes.Bne_Un, next_test);
else
ig.Emit (OpCodes.Beq, sec_begin);
} else {
ig.Emit (OpCodes.Ldloc, val);
EmitObjectInteger (ig, lit);
ig.Emit (OpCodes.Ceq);
if (label_count == 1)
ig.Emit (OpCodes.Brfalse, next_test);
else
ig.Emit (OpCodes.Brtrue, sec_begin);
}
}
}
if (label_count != 1 && ss != last_section)
ig.Emit (OpCodes.Br, next_test);
if (null_found)
ig.MarkLabel (null_target);
ig.MarkLabel (sec_begin);
foreach (SwitchLabel sl in ss.Labels)
ig.MarkLabel (sl.ILLabelCode);
if (ss.Block.Emit (ec))
pending_goto_end = false;
else {
all_return = false;
pending_goto_end = true;
}
first_test = false;
}
if (!default_found){
ig.MarkLabel (default_target);
all_return = false;
}
ig.MarkLabel (next_test);
ig.MarkLabel (end_of_switch);
return all_return;
}
public override bool Resolve (EmitContext ec)
{
foreach (SwitchSection ss in Sections){
if (ss.Block.Resolve (ec) != true)
return false;
}
return true;
}
public override bool Emit (EmitContext ec)
{
Expr = Expr.Resolve (ec);
if (Expr == null)
return false;
Expression new_expr = SwitchGoverningType (ec, Expr.Type);
if (new_expr == null){
Report.Error (151, loc, "An integer type or string was expected for switch");
return false;
}
// Validate switch.
SwitchType = new_expr.Type;
if (!CheckSwitch (ec))
return false;
// Store variable for comparission purposes
LocalBuilder value = ec.ig.DeclareLocal (SwitchType);
new_expr.Emit (ec);
ec.ig.Emit (OpCodes.Stloc, value);
ILGenerator ig = ec.ig;
default_target = ig.DefineLabel ();
//
// Setup the codegen context
//
Label old_end = ec.LoopEnd;
Switch old_switch = ec.Switch;
ec.LoopEnd = ig.DefineLabel ();
ec.Switch = this;
// Emit Code.
bool all_return;
if (SwitchType == TypeManager.string_type)
all_return = SimpleSwitchEmit (ec, value);
else
all_return = TableSwitchEmit (ec, value);
// Restore context state.
ig.MarkLabel (ec.LoopEnd);
//
// Restore the previous context
//
ec.LoopEnd = old_end;
ec.Switch = old_switch;
return all_return;
}
}
public class Lock : Statement {
Expression expr;
Statement Statement;
public Lock (Expression expr, Statement stmt, Location l)
{
this.expr = expr;
Statement = stmt;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
expr = expr.Resolve (ec);
return Statement.Resolve (ec) && expr != null;
}
public override bool Emit (EmitContext ec)
{
Type type = expr.Type;
bool val;
if (type.IsValueType){
Report.Error (185, loc, "lock statement requires the expression to be " +
" a reference type (type is: `" +
TypeManager.CSharpName (type) + "'");
return false;
}
ILGenerator ig = ec.ig;
LocalBuilder temp = ig.DeclareLocal (type);
expr.Emit (ec);
ig.Emit (OpCodes.Dup);
ig.Emit (OpCodes.Stloc, temp);
ig.Emit (OpCodes.Call, TypeManager.void_monitor_enter_object);
// try
Label end = ig.BeginExceptionBlock ();
bool old_in_try = ec.InTry;
ec.InTry = true;
Label finish = ig.DefineLabel ();
val = Statement.Emit (ec);
ec.InTry = old_in_try;
// ig.Emit (OpCodes.Leave, finish);
ig.MarkLabel (finish);
// finally
ig.BeginFinallyBlock ();
ig.Emit (OpCodes.Ldloc, temp);
ig.Emit (OpCodes.Call, TypeManager.void_monitor_exit_object);
ig.EndExceptionBlock ();
return val;
}
}
public class Unchecked : Statement {
public readonly Block Block;
public Unchecked (Block b)
{
Block = b;
}
public override bool Resolve (EmitContext ec)
{
return Block.Resolve (ec);
}
public override bool Emit (EmitContext ec)
{
bool previous_state = ec.CheckState;
bool previous_state_const = ec.ConstantCheckState;
bool val;
ec.CheckState = false;
ec.ConstantCheckState = false;
val = Block.Emit (ec);
ec.CheckState = previous_state;
ec.ConstantCheckState = previous_state_const;
return val;
}
}
public class Checked : Statement {
public readonly Block Block;
public Checked (Block b)
{
Block = b;
}
public override bool Resolve (EmitContext ec)
{
return Block.Resolve (ec);
}
public override bool Emit (EmitContext ec)
{
bool previous_state = ec.CheckState;
bool previous_state_const = ec.ConstantCheckState;
bool val;
ec.CheckState = true;
ec.ConstantCheckState = true;
val = Block.Emit (ec);
ec.CheckState = previous_state;
ec.ConstantCheckState = previous_state_const;
return val;
}
}
public class Unsafe : Statement {
public readonly Block Block;
public Unsafe (Block b)
{
Block = b;
}
public override bool Resolve (EmitContext ec)
{
return Block.Resolve (ec);
}
public override bool Emit (EmitContext ec)
{
bool previous_state = ec.InUnsafe;
bool val;
ec.InUnsafe = true;
val = Block.Emit (ec);
ec.InUnsafe = previous_state;
return val;
}
}
//
// Fixed statement
//
public class Fixed : Statement {
string type;
ArrayList declarators;
Statement statement;
public Fixed (string type, ArrayList decls, Statement stmt, Location l)
{
this.type = type;
declarators = decls;
statement = stmt;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
return statement.Resolve (ec);
}
public override bool Emit (EmitContext ec)
{
ILGenerator ig = ec.ig;
Type t;
t = RootContext.LookupType (ec.DeclSpace, type, false, loc);
if (t == null)
return false;
bool is_ret = false;
foreach (Pair p in declarators){
VariableInfo vi = (VariableInfo) p.First;
Expression e = (Expression) p.Second;
//
// The rules for the possible declarators are pretty wise,
// but the production on the grammar is more concise.
//
// So we have to enforce these rules here.
//
// We do not resolve before doing the case 1 test,
// because the grammar is explicit in that the token &
// is present, so we need to test for this particular case.
//
//
// Case 1: & object.
//
if (e is Unary && ((Unary) e).Oper == Unary.Operator.AddressOf){
Expression child = ((Unary) e).Expr;
vi.MakePinned ();
if (child is ParameterReference || child is LocalVariableReference){
Report.Error (
213, loc,
"No need to use fixed statement for parameters or " +
"local variable declarations (address is already " +
"fixed)");
continue;
}
e = e.Resolve (ec);
if (e == null)
continue;
child = ((Unary) e).Expr;
if (!TypeManager.VerifyUnManaged (child.Type, loc))
continue;
//
// Store pointer in pinned location
//
e.Emit (ec);
ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
is_ret = statement.Emit (ec);
// Clear the pinned variable.
ig.Emit (OpCodes.Ldc_I4_0);
ig.Emit (OpCodes.Conv_U);
ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
continue;
}
e = e.Resolve (ec);
if (e == null)
continue;
//
// Case 2: Array
//
if (e.Type.IsArray){
Type array_type = e.Type.GetElementType ();
vi.MakePinned ();
//
// Provided that array_type is unmanaged,
//
if (!TypeManager.VerifyUnManaged (array_type, loc))
continue;
//
// and T* is implicitly convertible to the
// pointer type given in the fixed statement.
//
ArrayPtr array_ptr = new ArrayPtr (e);
Expression converted = Expression.ConvertImplicitRequired (
ec, array_ptr, vi.VariableType, loc);
if (converted == null)
continue;
//
// Store pointer in pinned location
//
converted.Emit (ec);
ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
is_ret = statement.Emit (ec);
// Clear the pinned variable.
ig.Emit (OpCodes.Ldc_I4_0);
ig.Emit (OpCodes.Conv_U);
ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
continue;
}
//
// Case 3: string
//
if (e.Type == TypeManager.string_type){
LocalBuilder pinned_string = ig.DeclareLocal (TypeManager.string_type);
TypeManager.MakePinned (pinned_string);
e.Emit (ec);
ig.Emit (OpCodes.Stloc, pinned_string);
Expression sptr = new StringPtr (pinned_string);
Expression converted = Expression.ConvertImplicitRequired (
ec, sptr, vi.VariableType, loc);
if (converted == null)
continue;
converted.Emit (ec);
ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
is_ret = statement.Emit (ec);
// Clear the pinned variable
ig.Emit (OpCodes.Ldnull);
ig.Emit (OpCodes.Stloc, pinned_string);
}
}
return is_ret;
}
}
public class Catch {
public readonly string Type;
public readonly string Name;
public readonly Block Block;
public readonly Location Location;
public Catch (string type, string name, Block block, Location l)
{
Type = type;
Name = name;
Block = block;
Location = l;
}
}
public class Try : Statement {
public readonly Block Fini, Block;
public readonly ArrayList Specific;
public readonly Catch General;
//
// specific, general and fini might all be null.
//
public Try (Block block, ArrayList specific, Catch general, Block fini)
{
if (specific == null && general == null){
Console.WriteLine ("CIR.Try: Either specific or general have to be non-null");
}
this.Block = block;
this.Specific = specific;
this.General = general;
this.Fini = fini;
}
public override bool Resolve (EmitContext ec)
{
bool ok = true;
if (General != null)
if (!General.Block.Resolve (ec))
ok = false;
foreach (Catch c in Specific){
if (!c.Block.Resolve (ec))
ok = false;
}
if (!Block.Resolve (ec))
ok = false;
if (Fini != null)
if (!Fini.Resolve (ec))
ok = false;
return ok;
}
public override bool Emit (EmitContext ec)
{
ILGenerator ig = ec.ig;
Label end;
Label finish = ig.DefineLabel ();;
bool returns;
end = ig.BeginExceptionBlock ();
bool old_in_try = ec.InTry;
ec.InTry = true;
returns = Block.Emit (ec);
ec.InTry = old_in_try;
//
// System.Reflection.Emit provides this automatically:
// ig.Emit (OpCodes.Leave, finish);
bool old_in_catch = ec.InCatch;
ec.InCatch = true;
DeclSpace ds = ec.DeclSpace;
foreach (Catch c in Specific){
Type catch_type = RootContext.LookupType (ds, c.Type, false, c.Location);
VariableInfo vi;
if (catch_type == null)
return false;
ig.BeginCatchBlock (catch_type);
if (c.Name != null){
vi = c.Block.GetVariableInfo (c.Name);
if (vi == null){
Console.WriteLine ("This should not happen! variable does not exist in this block");
Environment.Exit (0);
}
ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
} else
ig.Emit (OpCodes.Pop);
if (!c.Block.Emit (ec))
returns = false;
}
if (General != null){
ig.BeginCatchBlock (TypeManager.object_type);
ig.Emit (OpCodes.Pop);
if (!General.Block.Emit (ec))
returns = false;
}
ec.InCatch = old_in_catch;
ig.MarkLabel (finish);
if (Fini != null){
ig.BeginFinallyBlock ();
bool old_in_finally = ec.InFinally;
ec.InFinally = true;
Fini.Emit (ec);
ec.InFinally = old_in_finally;
}
ig.EndExceptionBlock ();
//
// FIXME: Is this correct?
// Replace with `returns' and check test-18, maybe we can
// perform an optimization here.
//
return returns;
}
}
//
// FIXME: We still do not support the expression variant of the using
// statement.
//
public class Using : Statement {
object expression_or_block;
Statement Statement;
public Using (object expression_or_block, Statement stmt, Location l)
{
this.expression_or_block = expression_or_block;
Statement = stmt;
loc = l;
}
//
// Emits the code for the case of using using a local variable declaration.
//
bool EmitLocalVariableDecls (EmitContext ec, string type_name, ArrayList var_list)
{
ILGenerator ig = ec.ig;
Expression [] converted_vars;
bool need_conv = false;
Type type = RootContext.LookupType (ec.DeclSpace, type_name, false, loc);
int i = 0;
if (type == null)
return false;
//
// The type must be an IDisposable or an implicit conversion
// must exist.
//
converted_vars = new Expression [var_list.Count];
if (!TypeManager.ImplementsInterface (type, TypeManager.idisposable_type)){
foreach (DictionaryEntry e in var_list){
Expression var = (Expression) e.Key;
var = var.Resolve (ec);
if (var == null)
return false;
converted_vars [i] = Expression.ConvertImplicit (
ec, var, TypeManager.idisposable_type, loc);
if (converted_vars [i] == null)
return false;
i++;
}
need_conv = true;
}
i = 0;
bool old_in_try = ec.InTry;
ec.InTry = true;
bool error = false;
foreach (DictionaryEntry e in var_list){
LocalVariableReference var = (LocalVariableReference) e.Key;
Expression expr = (Expression) e.Value;
Expression a;
a = new Assign (var, expr, loc);
a = a.Resolve (ec);
if (!need_conv)
converted_vars [i] = var;
i++;
if (a == null){
error = true;
continue;
}
((ExpressionStatement) a).EmitStatement (ec);
ig.BeginExceptionBlock ();
}
if (error)
return false;
Statement.Emit (ec);
ec.InTry = old_in_try;
bool old_in_finally = ec.InFinally;
ec.InFinally = true;
var_list.Reverse ();
foreach (DictionaryEntry e in var_list){
LocalVariableReference var = (LocalVariableReference) e.Key;
Label skip = ig.DefineLabel ();
i--;
ig.BeginFinallyBlock ();
var.Emit (ec);
ig.Emit (OpCodes.Brfalse, skip);
converted_vars [i].Emit (ec);
ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
ig.MarkLabel (skip);
ig.EndExceptionBlock ();
}
ec.InFinally = old_in_finally;
return false;
}
bool EmitExpression (EmitContext ec, Expression expr)
{
Type expr_type = expr.Type;
Expression conv = null;
if (!TypeManager.ImplementsInterface (expr_type, TypeManager.idisposable_type)){
conv = Expression.ConvertImplicit (
ec, expr, TypeManager.idisposable_type, loc);
if (conv == null)
return false;
}
//
// Make a copy of the expression and operate on that.
//
ILGenerator ig = ec.ig;
LocalBuilder local_copy = ig.DeclareLocal (expr_type);
if (conv != null)
conv.Emit (ec);
else
expr.Emit (ec);
ig.Emit (OpCodes.Stloc, local_copy);
bool old_in_try = ec.InTry;
ec.InTry = true;
ig.BeginExceptionBlock ();
Statement.Emit (ec);
ec.InTry = old_in_try;
Label skip = ig.DefineLabel ();
bool old_in_finally = ec.InFinally;
ig.BeginFinallyBlock ();
ig.Emit (OpCodes.Ldloc, local_copy);
ig.Emit (OpCodes.Brfalse, skip);
ig.Emit (OpCodes.Ldloc, local_copy);
ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
ig.MarkLabel (skip);
ec.InFinally = old_in_finally;
ig.EndExceptionBlock ();
return false;
}
public override bool Resolve (EmitContext ec)
{
return Statement.Resolve (ec);
}
public override bool Emit (EmitContext ec)
{
if (expression_or_block is DictionaryEntry){
string t = (string) ((DictionaryEntry) expression_or_block).Key;
ArrayList var_list = (ArrayList)((DictionaryEntry)expression_or_block).Value;
return EmitLocalVariableDecls (ec, t, var_list);
} if (expression_or_block is Expression){
Expression e = (Expression) expression_or_block;
e = e.Resolve (ec);
if (e == null)
return false;
return EmitExpression (ec, e);
}
return false;
}
}
///
/// Implementation of the foreach C# statement
///
public class Foreach : Statement {
string type;
LocalVariableReference variable;
Expression expr;
Statement statement;
public Foreach (string type, LocalVariableReference var, Expression expr,
Statement stmt, Location l)
{
this.type = type;
this.variable = var;
this.expr = expr;
statement = stmt;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
expr = expr.Resolve (ec);
return statement.Resolve (ec) && expr != null;
}
//
// Retrieves a `public bool MoveNext ()' method from the Type `t'
//
static MethodInfo FetchMethodMoveNext (Type t)
{
MemberInfo [] move_next_list;
move_next_list = TypeContainer.FindMembers (
t, MemberTypes.Method,
BindingFlags.Public | BindingFlags.Instance,
Type.FilterName, "MoveNext");
if (move_next_list == null || move_next_list.Length == 0)
return null;
foreach (MemberInfo m in move_next_list){
MethodInfo mi = (MethodInfo) m;
Type [] args;
args = TypeManager.GetArgumentTypes (mi);
if (args != null && args.Length == 0){
if (mi.ReturnType == TypeManager.bool_type)
return mi;
}
}
return null;
}
//
// Retrieves a `public T get_Current ()' method from the Type `t'
//
static MethodInfo FetchMethodGetCurrent (Type t)
{
MemberInfo [] move_next_list;
move_next_list = TypeContainer.FindMembers (
t, MemberTypes.Method,
BindingFlags.Public | BindingFlags.Instance,
Type.FilterName, "get_Current");
if (move_next_list == null || move_next_list.Length == 0)
return null;
foreach (MemberInfo m in move_next_list){
MethodInfo mi = (MethodInfo) m;
Type [] args;
args = TypeManager.GetArgumentTypes (mi);
if (args != null && args.Length == 0)
return mi;
}
return null;
}
//
// This struct records the helper methods used by the Foreach construct
//
class ForeachHelperMethods {
public EmitContext ec;
public MethodInfo get_enumerator;
public MethodInfo move_next;
public MethodInfo get_current;
public ForeachHelperMethods (EmitContext ec)
{
this.ec = ec;
}
}
static bool GetEnumeratorFilter (MemberInfo m, object criteria)
{
if (m == null)
return false;
if (!(m is MethodInfo))
return false;
if (m.Name != "GetEnumerator")
return false;
MethodInfo mi = (MethodInfo) m;
Type [] args = TypeManager.GetArgumentTypes (mi);
if (args != null){
if (args.Length != 0)
return false;
}
ForeachHelperMethods hm = (ForeachHelperMethods) criteria;
EmitContext ec = hm.ec;
//
// Check whether GetEnumerator is accessible to us
//
MethodAttributes prot = mi.Attributes & MethodAttributes.MemberAccessMask;
Type declaring = mi.DeclaringType;
if (prot == MethodAttributes.Private){
if (declaring != ec.ContainerType)
return false;
} else if (prot == MethodAttributes.FamANDAssem){
// If from a different assembly, false
if (!(mi is MethodBuilder))
return false;
//
// Are we being invoked from the same class, or from a derived method?
//
if (ec.ContainerType != declaring){
if (!ec.ContainerType.IsSubclassOf (declaring))
return false;
}
} else if (prot == MethodAttributes.FamORAssem){
if (!(mi is MethodBuilder ||
ec.ContainerType == declaring ||
ec.ContainerType.IsSubclassOf (declaring)))
return false;
} if (prot == MethodAttributes.Family){
if (!(ec.ContainerType == declaring ||
ec.ContainerType.IsSubclassOf (declaring)))
return false;
}
//
// Ok, we can access it, now make sure that we can do something
// with this `GetEnumerator'
//
if (mi.ReturnType == TypeManager.ienumerator_type ||
TypeManager.ienumerator_type.IsAssignableFrom (mi.ReturnType)){
hm.move_next = TypeManager.bool_movenext_void;
hm.get_current = TypeManager.object_getcurrent_void;
return true;
}
//
// Ok, so they dont return an IEnumerable, we will have to
// find if they support the GetEnumerator pattern.
//
Type return_type = mi.ReturnType;
hm.move_next = FetchMethodMoveNext (return_type);
if (hm.move_next == null)
return false;
hm.get_current = FetchMethodGetCurrent (return_type);
if (hm.get_current == null)
return false;
return true;
}
///
/// This filter is used to find the GetEnumerator method
/// on which IEnumerator operates
///
static MemberFilter FilterEnumerator;
static Foreach ()
{
FilterEnumerator = new MemberFilter (GetEnumeratorFilter);
}
void error1579 (Type t)
{
Report.Error (1579, loc,
"foreach statement cannot operate on variables of type `" +
t.FullName + "' because that class does not provide a " +
" GetEnumerator method or it is inaccessible");
}
static bool TryType (Type t, ForeachHelperMethods hm)
{
MemberInfo [] mi;
mi = TypeContainer.FindMembers (t, MemberTypes.Method,
BindingFlags.Public | BindingFlags.NonPublic |
BindingFlags.Instance,
FilterEnumerator, hm);
if (mi == null || mi.Length == 0)
return false;
hm.get_enumerator = (MethodInfo) mi [0];
return true;
}
//
// Looks for a usable GetEnumerator in the Type, and if found returns
// the three methods that participate: GetEnumerator, MoveNext and get_Current
//
ForeachHelperMethods ProbeCollectionType (EmitContext ec, Type t)
{
ForeachHelperMethods hm = new ForeachHelperMethods (ec);
if (TryType (t, hm))
return hm;
//
// Now try to find the method in the interfaces
//
while (t != null){
Type [] ifaces = t.GetInterfaces ();
foreach (Type i in ifaces){
if (TryType (i, hm))
return hm;
}
//
// Since TypeBuilder.GetInterfaces only returns the interface
// types for this type, we have to keep looping, but once
// we hit a non-TypeBuilder (ie, a Type), then we know we are
// done, because it returns all the types
//
if ((t is TypeBuilder))
t = t.BaseType;
else
break;
}
return null;
}
//
// FIXME: possible optimization.
// We might be able to avoid creating `empty' if the type is the sam
//
bool EmitCollectionForeach (EmitContext ec, Type var_type, ForeachHelperMethods hm)
{
ILGenerator ig = ec.ig;
LocalBuilder enumerator, disposable;
Expression empty = new EmptyExpression ();
Expression conv;
//
// FIXME: maybe we can apply the same trick we do in the
// array handling to avoid creating empty and conv in some cases.
//
// Although it is not as important in this case, as the type
// will not likely be object (what the enumerator will return).
//
conv = Expression.ConvertExplicit (ec, empty, var_type, loc);
if (conv == null)
return false;
enumerator = ig.DeclareLocal (TypeManager.ienumerator_type);
disposable = ig.DeclareLocal (TypeManager.idisposable_type);
//
// Instantiate the enumerator
//
if (expr.Type.IsValueType){
if (expr is IMemoryLocation){
IMemoryLocation ml = (IMemoryLocation) expr;
ml.AddressOf (ec, AddressOp.Load);
} else
throw new Exception ("Expr " + expr + " of type " + expr.Type +
" does not implement IMemoryLocation");
ig.Emit (OpCodes.Call, hm.get_enumerator);
} else {
expr.Emit (ec);
ig.Emit (OpCodes.Callvirt, hm.get_enumerator);
}
ig.Emit (OpCodes.Stloc, enumerator);
//
// Protect the code in a try/finalize block, so that
// if the beast implement IDisposable, we get rid of it
//
Label l = ig.BeginExceptionBlock ();
bool old_in_try = ec.InTry;
ec.InTry = true;
Label end_try = ig.DefineLabel ();
ig.MarkLabel (ec.LoopBegin);
ig.Emit (OpCodes.Ldloc, enumerator);
ig.Emit (OpCodes.Callvirt, hm.move_next);
ig.Emit (OpCodes.Brfalse, end_try);
ig.Emit (OpCodes.Ldloc, enumerator);
ig.Emit (OpCodes.Callvirt, hm.get_current);
variable.EmitAssign (ec, conv);
statement.Emit (ec);
ig.Emit (OpCodes.Br, ec.LoopBegin);
ig.MarkLabel (end_try);
ec.InTry = old_in_try;
// The runtime provides this for us.
// ig.Emit (OpCodes.Leave, end);
//
// Now the finally block
//
Label end_finally = ig.DefineLabel ();
bool old_in_finally = ec.InFinally;
ec.InFinally = true;
ig.BeginFinallyBlock ();
ig.Emit (OpCodes.Ldloc, enumerator);
ig.Emit (OpCodes.Isinst, TypeManager.idisposable_type);
ig.Emit (OpCodes.Stloc, disposable);
ig.Emit (OpCodes.Ldloc, disposable);
ig.Emit (OpCodes.Brfalse, end_finally);
ig.Emit (OpCodes.Ldloc, disposable);
ig.Emit (OpCodes.Callvirt, TypeManager.void_dispose_void);
ig.MarkLabel (end_finally);
ec.InFinally = old_in_finally;
// The runtime generates this anyways.
// ig.Emit (OpCodes.Endfinally);
ig.EndExceptionBlock ();
ig.MarkLabel (ec.LoopEnd);
return false;
}
//
// FIXME: possible optimization.
// We might be able to avoid creating `empty' if the type is the sam
//
bool EmitArrayForeach (EmitContext ec, Type var_type)
{
Type array_type = expr.Type;
Type element_type = array_type.GetElementType ();
Expression conv = null;
Expression empty = new EmptyExpression (element_type);
conv = Expression.ConvertExplicit (ec, empty, var_type, loc);
if (conv == null)
return false;
int rank = array_type.GetArrayRank ();
ILGenerator ig = ec.ig;
LocalBuilder copy = ig.DeclareLocal (array_type);
//
// Make our copy of the array
//
expr.Emit (ec);
ig.Emit (OpCodes.Stloc, copy);
if (rank == 1){
LocalBuilder counter = ig.DeclareLocal (TypeManager.int32_type);
Label loop, test;
ig.Emit (OpCodes.Ldc_I4_0);
ig.Emit (OpCodes.Stloc, counter);
test = ig.DefineLabel ();
ig.Emit (OpCodes.Br, test);
loop = ig.DefineLabel ();
ig.MarkLabel (loop);
ig.Emit (OpCodes.Ldloc, copy);
ig.Emit (OpCodes.Ldloc, counter);
ArrayAccess.EmitLoadOpcode (ig, var_type);
variable.EmitAssign (ec, conv);
statement.Emit (ec);
ig.MarkLabel (ec.LoopBegin);
ig.Emit (OpCodes.Ldloc, counter);
ig.Emit (OpCodes.Ldc_I4_1);
ig.Emit (OpCodes.Add);
ig.Emit (OpCodes.Stloc, counter);
ig.MarkLabel (test);
ig.Emit (OpCodes.Ldloc, counter);
ig.Emit (OpCodes.Ldloc, copy);
ig.Emit (OpCodes.Ldlen);
ig.Emit (OpCodes.Conv_I4);
ig.Emit (OpCodes.Blt, loop);
} else {
LocalBuilder [] dim_len = new LocalBuilder [rank];
LocalBuilder [] dim_count = new LocalBuilder [rank];
Label [] loop = new Label [rank];
Label [] test = new Label [rank];
int dim;
for (dim = 0; dim < rank; dim++){
dim_len [dim] = ig.DeclareLocal (TypeManager.int32_type);
dim_count [dim] = ig.DeclareLocal (TypeManager.int32_type);
test [dim] = ig.DefineLabel ();
loop [dim] = ig.DefineLabel ();
}
for (dim = 0; dim < rank; dim++){
ig.Emit (OpCodes.Ldloc, copy);
IntLiteral.EmitInt (ig, dim);
ig.Emit (OpCodes.Callvirt, TypeManager.int_getlength_int);
ig.Emit (OpCodes.Stloc, dim_len [dim]);
}
for (dim = 0; dim < rank; dim++){
ig.Emit (OpCodes.Ldc_I4_0);
ig.Emit (OpCodes.Stloc, dim_count [dim]);
ig.Emit (OpCodes.Br, test [dim]);
ig.MarkLabel (loop [dim]);
}
ig.Emit (OpCodes.Ldloc, copy);
for (dim = 0; dim < rank; dim++)
ig.Emit (OpCodes.Ldloc, dim_count [dim]);
//
// FIXME: Maybe we can cache the computation of `get'?
//
Type [] args = new Type [rank];
MethodInfo get;
for (int i = 0; i < rank; i++)
args [i] = TypeManager.int32_type;
ModuleBuilder mb = CodeGen.ModuleBuilder;
get = mb.GetArrayMethod (
array_type, "Get",
CallingConventions.HasThis| CallingConventions.Standard,
var_type, args);
ig.Emit (OpCodes.Call, get);
variable.EmitAssign (ec, conv);
statement.Emit (ec);
ig.MarkLabel (ec.LoopBegin);
for (dim = rank - 1; dim >= 0; dim--){
ig.Emit (OpCodes.Ldloc, dim_count [dim]);
ig.Emit (OpCodes.Ldc_I4_1);
ig.Emit (OpCodes.Add);
ig.Emit (OpCodes.Stloc, dim_count [dim]);
ig.MarkLabel (test [dim]);
ig.Emit (OpCodes.Ldloc, dim_count [dim]);
ig.Emit (OpCodes.Ldloc, dim_len [dim]);
ig.Emit (OpCodes.Blt, loop [dim]);
}
}
ig.MarkLabel (ec.LoopEnd);
return false;
}
public override bool Emit (EmitContext ec)
{
Type var_type;
bool ret_val;
var_type = RootContext.LookupType (ec.DeclSpace, type, false, loc);
if (var_type == null)
return false;
//
// We need an instance variable. Not sure this is the best
// way of doing this.
//
// FIXME: When we implement propertyaccess, will those turn
// out to return values in ExprClass? I think they should.
//
if (!(expr.eclass == ExprClass.Variable || expr.eclass == ExprClass.Value ||
expr.eclass == ExprClass.PropertyAccess)){
error1579 (expr.Type);
return false;
}
ILGenerator ig = ec.ig;
Label old_begin = ec.LoopBegin, old_end = ec.LoopEnd;
bool old_inloop = ec.InLoop;
ec.LoopBegin = ig.DefineLabel ();
ec.LoopEnd = ig.DefineLabel ();
ec.InLoop = true;
if (expr.Type.IsArray)
ret_val = EmitArrayForeach (ec, var_type);
else {
ForeachHelperMethods hm;
hm = ProbeCollectionType (ec, expr.Type);
if (hm == null){
error1579 (expr.Type);
return false;
}
ret_val = EmitCollectionForeach (ec, var_type, hm);
}
ec.LoopBegin = old_begin;
ec.LoopEnd = old_end;
ec.InLoop = old_inloop;
return ret_val;
}
}
}