//
// statement.cs: Statement representation for the IL tree.
//
// Author:
// Miguel de Icaza (miguel@ximian.com)
// Martin Baulig (martin@gnome.org)
//
// (C) 2001, 2002, 2003 Ximian, Inc.
//
using System;
using System.Text;
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.
///
protected abstract bool DoEmit (EmitContext ec);
///
/// Return value indicates whether all code paths emitted return.
///
public virtual bool Emit (EmitContext ec)
{
ec.Mark (loc, true);
return DoEmit (ec);
}
///
/// Encapsulates the emission of a boolean test and jumping to a
/// destination.
///
/// This will emit the bool expression in `bool_expr' and if
/// `target_is_for_true' is true, then the code will generate a
/// brtrue to the target. Otherwise a brfalse.
///
public static void EmitBoolExpression (EmitContext ec, Expression bool_expr,
Label target, bool target_is_for_true)
{
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);
}
} else if (bool_expr is Binary){
Binary b = (Binary) bool_expr;
if (b.EmitBranchable (ec, target, target_is_for_true))
return;
}
if (!invert)
bool_expr.Emit (ec);
if (target_is_for_true){
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;
}
protected override bool DoEmit (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)
{
Report.Debug (1, "START IF BLOCK", loc);
expr = Expression.ResolveBoolean (ec, expr, loc);
if (expr == null){
return false;
}
ec.StartFlowBranching (FlowBranching.BranchingType.Block, loc);
if (!TrueStatement.Resolve (ec)) {
ec.KillFlowBranching ();
return false;
}
ec.CurrentBranching.CreateSibling (FlowBranching.SiblingType.Conditional);
if ((FalseStatement != null) && !FalseStatement.Resolve (ec)) {
ec.KillFlowBranching ();
return false;
}
ec.EndFlowBranching ();
Report.Debug (1, "END IF BLOCK", loc);
return true;
}
protected override bool DoEmit (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;
bool infinite, may_return;
public Do (Statement statement, Expression boolExpr, Location l)
{
expr = boolExpr;
EmbeddedStatement = statement;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
bool ok = true;
ec.StartFlowBranching (FlowBranching.BranchingType.LoopBlock, loc);
if (!EmbeddedStatement.Resolve (ec))
ok = false;
expr = Expression.ResolveBoolean (ec, expr, loc);
if (expr == null)
ok = false;
else if (expr is BoolConstant){
bool res = ((BoolConstant) expr).Value;
if (res)
infinite = true;
}
ec.CurrentBranching.Infinite = infinite;
FlowBranching.FlowReturns returns = ec.EndFlowBranching ();
may_return = returns != FlowBranching.FlowReturns.Never;
return ok;
}
protected override bool DoEmit (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;
int old_loop_begin_try_catch_level = ec.LoopBeginTryCatchLevel;
ec.LoopBegin = ig.DefineLabel ();
ec.LoopEnd = ig.DefineLabel ();
ec.InLoop = true;
ec.LoopBeginTryCatchLevel = ec.TryCatchLevel;
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.LoopBeginTryCatchLevel = old_loop_begin_try_catch_level;
ec.LoopBegin = old_begin;
ec.LoopEnd = old_end;
ec.InLoop = old_inloop;
if (infinite)
return may_return == false;
else
return false;
}
}
public class While : Statement {
public Expression expr;
public readonly Statement Statement;
bool may_return, empty, infinite;
public While (Expression boolExpr, Statement statement, Location l)
{
this.expr = boolExpr;
Statement = statement;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
bool ok = true;
expr = Expression.ResolveBoolean (ec, expr, loc);
if (expr == null)
return false;
ec.StartFlowBranching (FlowBranching.BranchingType.LoopBlock, loc);
//
// Inform whether we are infinite or not
//
if (expr is BoolConstant){
BoolConstant bc = (BoolConstant) expr;
if (bc.Value == false){
Warning_DeadCodeFound (Statement.loc);
empty = true;
} else
infinite = true;
} else {
//
// We are not infinite, so the loop may or may not be executed.
//
ec.CurrentBranching.CreateSibling (FlowBranching.SiblingType.Conditional);
}
if (!Statement.Resolve (ec))
ok = false;
if (empty)
ec.KillFlowBranching ();
else {
ec.CurrentBranching.Infinite = infinite;
FlowBranching.FlowReturns returns = ec.EndFlowBranching ();
may_return = returns != FlowBranching.FlowReturns.Never;
}
return ok;
}
protected override bool DoEmit (EmitContext ec)
{
if (empty)
return false;
ILGenerator ig = ec.ig;
Label old_begin = ec.LoopBegin;
Label old_end = ec.LoopEnd;
bool old_inloop = ec.InLoop;
int old_loop_begin_try_catch_level = ec.LoopBeginTryCatchLevel;
bool ret;
ec.LoopBegin = ig.DefineLabel ();
ec.LoopEnd = ig.DefineLabel ();
ec.InLoop = true;
ec.LoopBeginTryCatchLevel = ec.TryCatchLevel;
//
// Inform whether we are infinite or not
//
if (expr is BoolConstant){
BoolConstant bc = (BoolConstant) expr;
ig.MarkLabel (ec.LoopBegin);
Statement.Emit (ec);
ig.Emit (OpCodes.Br, ec.LoopBegin);
//
// Inform that we are infinite (ie, `we return'), only
// if we do not `break' inside the code.
//
ret = may_return == false;
ig.MarkLabel (ec.LoopEnd);
} else {
Label while_loop = ig.DefineLabel ();
ig.Emit (OpCodes.Br, ec.LoopBegin);
ig.MarkLabel (while_loop);
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;
ec.LoopBeginTryCatchLevel = old_loop_begin_try_catch_level;
return ret;
}
}
public class For : Statement {
Expression Test;
readonly Statement InitStatement;
readonly Statement Increment;
readonly Statement Statement;
bool may_return, infinite, empty;
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 (InitStatement != null){
if (!InitStatement.Resolve (ec))
ok = false;
}
if (Test != null){
Test = Expression.ResolveBoolean (ec, Test, loc);
if (Test == null)
ok = false;
else if (Test is BoolConstant){
BoolConstant bc = (BoolConstant) Test;
if (bc.Value == false){
Warning_DeadCodeFound (Statement.loc);
empty = true;
} else
infinite = true;
}
} else
infinite = true;
ec.StartFlowBranching (FlowBranching.BranchingType.LoopBlock, loc);
if (!infinite)
ec.CurrentBranching.CreateSibling (FlowBranching.SiblingType.Conditional);
if (!Statement.Resolve (ec))
ok = false;
if (Increment != null){
if (!Increment.Resolve (ec))
ok = false;
}
if (empty)
ec.KillFlowBranching ();
else {
ec.CurrentBranching.Infinite = infinite;
FlowBranching.FlowReturns returns = ec.EndFlowBranching ();
may_return = returns != FlowBranching.FlowReturns.Never;
}
return ok;
}
protected override bool DoEmit (EmitContext ec)
{
if (empty)
return false;
ILGenerator ig = ec.ig;
Label old_begin = ec.LoopBegin;
Label old_end = ec.LoopEnd;
bool old_inloop = ec.InLoop;
int old_loop_begin_try_catch_level = ec.LoopBeginTryCatchLevel;
Label loop = ig.DefineLabel ();
Label test = ig.DefineLabel ();
if (InitStatement != null)
if (! (InitStatement is EmptyStatement))
InitStatement.Emit (ec);
ec.LoopBegin = ig.DefineLabel ();
ec.LoopEnd = ig.DefineLabel ();
ec.InLoop = true;
ec.LoopBeginTryCatchLevel = ec.TryCatchLevel;
ig.Emit (OpCodes.Br, test);
ig.MarkLabel (loop);
Statement.Emit (ec);
ig.MarkLabel (ec.LoopBegin);
if (!(Increment is EmptyStatement))
Increment.Emit (ec);
ig.MarkLabel (test);
//
// If test is null, there is no test, and we are just
// an infinite loop
//
if (Test != null){
//
// The Resolve code already catches the case for Test == BoolConstant (false)
// so we know that this is true
//
if (Test is BoolConstant)
ig.Emit (OpCodes.Br, loop);
else
EmitBoolExpression (ec, Test, loop, true);
} else
ig.Emit (OpCodes.Br, loop);
ig.MarkLabel (ec.LoopEnd);
ec.LoopBegin = old_begin;
ec.LoopEnd = old_end;
ec.InLoop = old_inloop;
ec.LoopBeginTryCatchLevel = old_loop_begin_try_catch_level;
//
// Inform whether we are infinite or not
//
if (Test != null){
if (Test is BoolConstant){
BoolConstant bc = (BoolConstant) Test;
if (bc.Value)
return may_return == false;
}
return false;
} else
return may_return == false;
}
}
public class StatementExpression : Statement {
ExpressionStatement expr;
public StatementExpression (ExpressionStatement expr, Location l)
{
this.expr = expr;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
expr = expr.ResolveStatement (ec);
return expr != null;
}
protected override bool DoEmit (EmitContext ec)
{
ILGenerator ig = ec.ig;
expr.EmitStatement (ec);
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;
}
if (ec.InIterator){
Report.Error (-206, loc, "Return statement not allowed inside iterators");
return false;
}
FlowBranching.UsageVector vector = ec.CurrentBranching.CurrentUsageVector;
if (ec.CurrentBranching.InTryBlock ())
ec.CurrentBranching.AddFinallyVector (vector);
else
vector.CheckOutParameters (ec.CurrentBranching);
ec.CurrentBranching.Return ();
return true;
}
protected override bool DoEmit (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 true;
}
} else {
if (Expr == null){
Report.Error (126, loc, "An object of type `" +
TypeManager.CSharpName (ec.ReturnType) + "' is " +
"expected for the return statement");
return true;
}
if (Expr.Type != ec.ReturnType)
Expr = Convert.ImplicitConversionRequired (
ec, Expr, ec.ReturnType, loc);
if (Expr == null)
return true;
Expr.Emit (ec);
if (ec.InTry || ec.InCatch)
ec.ig.Emit (OpCodes.Stloc, ec.TemporaryReturn ());
}
if (ec.InTry || ec.InCatch) {
if (!ec.HasReturnLabel) {
ec.ReturnLabel = ec.ig.DefineLabel ();
ec.HasReturnLabel = true;
}
ec.ig.Emit (OpCodes.Leave, ec.ReturnLabel);
} else {
ec.ig.Emit (OpCodes.Ret);
ec.NeedExplicitReturn = false;
}
return true;
}
}
public class Goto : Statement {
string target;
Block block;
LabeledStatement label;
public override bool Resolve (EmitContext ec)
{
label = block.LookupLabel (target);
if (label == null){
Report.Error (
159, loc,
"No such label `" + target + "' in this scope");
return false;
}
// If this is a forward goto.
if (!label.IsDefined)
label.AddUsageVector (ec.CurrentBranching.CurrentUsageVector);
ec.CurrentBranching.Goto ();
return true;
}
public Goto (Block parent_block, string label, Location l)
{
block = parent_block;
loc = l;
target = label;
}
public string Target {
get {
return target;
}
}
protected override bool DoEmit (EmitContext ec)
{
Label l = label.LabelTarget (ec);
ec.ig.Emit (OpCodes.Br, l);
return false;
}
}
public class LabeledStatement : Statement {
public readonly Location Location;
string label_name;
bool defined;
bool referenced;
Label label;
ArrayList vectors;
public LabeledStatement (string label_name, Location l)
{
this.label_name = label_name;
this.Location = l;
}
public Label LabelTarget (EmitContext ec)
{
if (defined)
return label;
label = ec.ig.DefineLabel ();
defined = true;
return label;
}
public bool IsDefined {
get {
return defined;
}
}
public bool HasBeenReferenced {
get {
return referenced;
}
}
public void AddUsageVector (FlowBranching.UsageVector vector)
{
if (vectors == null)
vectors = new ArrayList ();
vectors.Add (vector.Clone ());
}
public override bool Resolve (EmitContext ec)
{
ec.CurrentBranching.Label (vectors);
referenced = true;
return true;
}
protected override bool DoEmit (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 Resolve (EmitContext ec)
{
ec.CurrentBranching.Goto ();
return true;
}
protected override bool DoEmit (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;
Label label;
public GotoCase (Expression e, Location l)
{
expr = e;
loc = l;
}
public override bool Resolve (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");
return false;
}
label = sl.ILLabelCode;
ec.CurrentBranching.Goto ();
return true;
}
protected override bool DoEmit (EmitContext ec)
{
ec.ig.Emit (OpCodes.Br, label);
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;
ExprClass eclass = expr.eclass;
if (!(eclass == ExprClass.Variable || eclass == ExprClass.PropertyAccess ||
eclass == ExprClass.Value || eclass == ExprClass.IndexerAccess)) {
expr.Error_UnexpectedKind ("value, variable, property or indexer access ");
return false;
}
Type t = expr.Type;
if ((t != TypeManager.exception_type) &&
!t.IsSubclassOf (TypeManager.exception_type) &&
!(expr is NullLiteral)) {
Report.Error (155, loc,
"The type caught or thrown must be derived " +
"from System.Exception");
return false;
}
}
ec.CurrentBranching.Throw ();
return true;
}
protected override bool DoEmit (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 Resolve (EmitContext ec)
{
ec.CurrentBranching.MayLeaveLoop = true;
ec.CurrentBranching.Break ();
return true;
}
protected override bool DoEmit (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;
}
if (ec.InTry || ec.InCatch)
ig.Emit (OpCodes.Leave, ec.LoopEnd);
else
ig.Emit (OpCodes.Br, ec.LoopEnd);
return false;
}
}
public class Continue : Statement {
public Continue (Location l)
{
loc = l;
}
public override bool Resolve (EmitContext ec)
{
ec.CurrentBranching.Goto ();
return true;
}
protected override bool DoEmit (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; }}
//
if (ec.TryCatchLevel > ec.LoopBeginTryCatchLevel)
ec.ig.Emit (OpCodes.Leave, begin);
else if (ec.TryCatchLevel < ec.LoopBeginTryCatchLevel)
throw new Exception ("Should never happen");
else
ec.ig.Emit (OpCodes.Br, begin);
return false;
}
}
public class LocalInfo {
public Expression Type;
//
// Most of the time a variable will be stored in a LocalBuilder
//
// But sometimes, it will be stored in a field. The context of the field will
// be stored in the EmitContext
//
//
public LocalBuilder LocalBuilder;
public FieldBuilder FieldBuilder;
public Type VariableType;
public readonly string Name;
public readonly Location Location;
public readonly Block Block;
public VariableInfo VariableInfo;
enum Flags : byte {
Used = 1,
Assigned = 2,
ReadOnly = 4,
Fixed = 8
}
Flags flags;
public LocalInfo (Expression type, string name, Block block, Location l)
{
Type = type;
Name = name;
Block = block;
Location = l;
}
public LocalInfo (TypeContainer tc, Block block, Location l)
{
VariableType = tc.TypeBuilder;
Block = block;
Location = l;
}
public bool IsThisAssigned (EmitContext ec, Location loc)
{
if (VariableInfo == null)
throw new Exception ();
if (!ec.DoFlowAnalysis || ec.CurrentBranching.IsAssigned (VariableInfo))
return true;
return VariableInfo.TypeInfo.IsFullyInitialized (ec.CurrentBranching, VariableInfo, loc);
}
public bool Resolve (DeclSpace decl)
{
if (VariableType == null)
VariableType = decl.ResolveType (Type, false, Location);
if (VariableType == null)
return false;
return true;
}
public void MakePinned ()
{
TypeManager.MakePinned (LocalBuilder);
flags |= Flags.Fixed;
}
public bool IsFixed {
get {
if (((flags & Flags.Fixed) != 0) || TypeManager.IsValueType (VariableType))
return true;
return false;
}
}
public override string ToString ()
{
return String.Format ("LocalInfo ({0},{1},{2},{3})",
Name, Type, VariableInfo, Location);
}
public bool Used {
get {
return (flags & Flags.Used) != 0;
}
set {
flags = value ? (flags | Flags.Used) : (flags & ~Flags.Used);
}
}
public bool Assigned {
get {
return (flags & Flags.Assigned) != 0;
}
set {
flags = value ? (flags | Flags.Assigned) : (flags & ~Flags.Assigned);
}
}
public bool ReadOnly {
get {
return (flags & Flags.ReadOnly) != 0;
}
set {
flags = value ? (flags | Flags.ReadOnly) : (flags & ~Flags.ReadOnly);
}
}
}
///
/// 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 Location StartLocation;
public Location EndLocation = Location.Null;
[Flags]
public enum Flags : byte {
Implicit = 1,
Unchecked = 2,
BlockUsed = 4,
VariablesInitialized = 8,
HasRet = 16
}
Flags flags;
public bool Implicit {
get {
return (flags & Flags.Implicit) != 0;
}
}
public bool Unchecked {
get {
return (flags & Flags.Unchecked) != 0;
}
set {
flags |= Flags.Unchecked;
}
}
//
// 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;
//
// If this is a switch section, the enclosing switch block.
//
Block switch_block;
static int id;
int this_id;
public Block (Block parent)
: this (parent, (Flags) 0, Location.Null, Location.Null)
{ }
public Block (Block parent, Flags flags)
: this (parent, flags, Location.Null, Location.Null)
{ }
public Block (Block parent, Flags flags, Parameters parameters)
: this (parent, flags, parameters, Location.Null, Location.Null)
{ }
public Block (Block parent, Location start, Location end)
: this (parent, (Flags) 0, start, end)
{ }
public Block (Block parent, Parameters parameters, Location start, Location end)
: this (parent, (Flags) 0, parameters, start, end)
{ }
public Block (Block parent, Flags flags, Location start, Location end)
: this (parent, flags, Parameters.EmptyReadOnlyParameters, start, end)
{ }
public Block (Block parent, Flags flags, Parameters parameters,
Location start, Location end)
{
if (parent != null)
parent.AddChild (this);
this.Parent = parent;
this.flags = flags;
this.parameters = parameters;
this.StartLocation = start;
this.EndLocation = end;
this.loc = start;
this_id = id++;
statements = new ArrayList ();
}
public Block CreateSwitchBlock (Location start)
{
Block new_block = new Block (this, start, start);
new_block.switch_block = this;
return new_block;
}
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 (switch_block != null)
return switch_block.AddLabel (name, 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 (switch_block != null)
return switch_block.LookupLabel (name);
if (labels != null){
if (labels.Contains (name))
return ((LabeledStatement) labels [name]);
}
if (Parent != null)
return Parent.LookupLabel (name);
return null;
}
LocalInfo this_variable = null;
//
// Returns the "this" instance variable of this block.
// See AddThisVariable() for more information.
//
public LocalInfo ThisVariable {
get {
if (this_variable != null)
return this_variable;
else if (Parent != null)
return Parent.ThisVariable;
else
return null;
}
}
Hashtable child_variable_names;
//
// Marks a variable with name @name as being used in a child block.
// If a variable name has been used in a child block, it's illegal to
// declare a variable with the same name in the current block.
//
public void AddChildVariableName (string name)
{
if (child_variable_names == null)
child_variable_names = new Hashtable ();
if (!child_variable_names.Contains (name))
child_variable_names.Add (name, true);
}
//
// Marks all variables from block @block and all its children as being
// used in a child block.
//
public void AddChildVariableNames (Block block)
{
if (block.Variables != null) {
foreach (string name in block.Variables.Keys)
AddChildVariableName (name);
}
if (block.children != null) {
foreach (Block child in block.children)
AddChildVariableNames (child);
}
if (block.child_variable_names != null) {
foreach (string name in block.child_variable_names.Keys)
AddChildVariableName (name);
}
}
//
// Checks whether a variable name has already been used in a child block.
//
public bool IsVariableNameUsedInChildBlock (string name)
{
if (child_variable_names == null)
return false;
return child_variable_names.Contains (name);
}
//
// This is used by non-static `struct' constructors which do not have an
// initializer - in this case, the constructor must initialize all of the
// struct's fields. To do this, we add a "this" variable and use the flow
// analysis code to ensure that it's been fully initialized before control
// leaves the constructor.
//
public LocalInfo AddThisVariable (TypeContainer tc, Location l)
{
if (this_variable != null)
return this_variable;
if (variables == null)
variables = new Hashtable ();
this_variable = new LocalInfo (tc, this, l);
variables.Add ("this", this_variable);
return this_variable;
}
public LocalInfo AddVariable (Expression type, string name, Parameters pars, Location l)
{
if (variables == null)
variables = new Hashtable ();
LocalInfo vi = GetLocalInfo (name);
if (vi != null) {
if (vi.Block != this)
Report.Error (136, l, "A local variable named `" + name + "' " +
"cannot be declared in this scope since it would " +
"give a different meaning to `" + name + "', which " +
"is already used in a `parent or current' scope to " +
"denote something else");
else
Report.Error (128, l, "A local variable `" + name + "' is already " +
"defined in this scope");
return null;
}
if (IsVariableNameUsedInChildBlock (name)) {
Report.Error (136, l, "A local variable named `" + name + "' " +
"cannot be declared in this scope since it would " +
"give a different meaning to `" + name + "', which " +
"is already used in a `child' scope to denote something " +
"else");
return null;
}
if (pars != null) {
int idx = 0;
Parameter p = pars.GetParameterByName (name, out idx);
if (p != null) {
Report.Error (136, l, "A local variable named `" + name + "' " +
"cannot be declared in this scope since it would " +
"give a different meaning to `" + name + "', which " +
"is already used in a `parent or current' scope to " +
"denote something else");
return null;
}
}
vi = new LocalInfo (type, name, this, l);
variables.Add (name, vi);
if ((flags & Flags.VariablesInitialized) != 0)
throw new Exception ();
// Console.WriteLine ("Adding {0} to {1}", name, ID);
return vi;
}
public bool AddConstant (Expression 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 LocalInfo GetLocalInfo (string name)
{
if (variables != null) {
object temp;
temp = variables [name];
if (temp != null){
return (LocalInfo) temp;
}
}
if (Parent != null)
return Parent.GetLocalInfo (name);
return null;
}
public Expression GetVariableType (string name)
{
LocalInfo vi = GetLocalInfo (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 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];
}
}
Parameters parameters = null;
public Parameters Parameters {
get {
if (Parent != null)
return Parent.Parameters;
return parameters;
}
}
///
/// 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);
flags |= Flags.BlockUsed;
}
public bool Used {
get {
return (flags & Flags.BlockUsed) != 0;
}
}
public void Use ()
{
flags |= Flags.BlockUsed;
}
VariableMap param_map, local_map;
public VariableMap ParameterMap {
get {
if ((flags & Flags.VariablesInitialized) == 0)
throw new Exception ();
return param_map;
}
}
public VariableMap LocalMap {
get {
if ((flags & Flags.VariablesInitialized) == 0)
throw new Exception ();
return local_map;
}
}
public bool LiftVariable (LocalInfo local_info)
{
return false;
}
///
/// Emits the variable declarations and labels.
///
///
/// tc: is our typecontainer (to resolve type references)
/// ig: is the code generator:
///
public void EmitMeta (EmitContext ec, InternalParameters ip)
{
DeclSpace ds = ec.DeclSpace;
ILGenerator ig = ec.ig;
//
// Compute the VariableMap's.
//
// Unfortunately, we don't know the type when adding variables with
// AddVariable(), so we need to compute this info here.
//
LocalInfo[] locals;
if (variables != null) {
foreach (LocalInfo li in variables.Values)
li.Resolve (ec.DeclSpace);
locals = new LocalInfo [variables.Count];
variables.Values.CopyTo (locals, 0);
} else
locals = new LocalInfo [0];
if (Parent != null)
local_map = new VariableMap (Parent.LocalMap, locals);
else
local_map = new VariableMap (locals);
param_map = new VariableMap (ip);
flags |= Flags.VariablesInitialized;
bool old_check_state = ec.ConstantCheckState;
ec.ConstantCheckState = (flags & Flags.Unchecked) == 0;
bool remap_locals = ec.RemapToProxy;
//
// Process this block variables
//
if (variables != null){
foreach (DictionaryEntry de in variables){
string name = (string) de.Key;
LocalInfo vi = (LocalInfo) de.Value;
if (vi.VariableType == null)
continue;
Type variable_type = vi.VariableType;
if (variable_type.IsPointer){
//
// Am not really convinced that this test is required (Microsoft does it)
// but the fact is that you would not be able to use the pointer variable
// *anyways*
//
if (!TypeManager.VerifyUnManaged (TypeManager.GetElementType (variable_type),
vi.Location))
continue;
}
if (remap_locals)
vi.FieldBuilder = ec.MapVariable (name, vi.VariableType);
else
vi.LocalBuilder = ig.DeclareLocal (vi.VariableType);
if (constants == null)
continue;
Expression cv = (Expression) constants [name];
if (cv == null)
continue;
ec.CurrentBlock = this;
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);
}
}
ec.ConstantCheckState = old_check_state;
//
// Now, handle the children
//
if (children != null){
foreach (Block b in children)
b.EmitMeta (ec, ip);
}
}
public void UsageWarning ()
{
string name;
if (variables != null){
foreach (DictionaryEntry de in variables){
LocalInfo vi = (LocalInfo) 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;
bool ok = true;
ec.CurrentBlock = this;
ec.StartFlowBranching (this);
Report.Debug (1, "RESOLVE BLOCK", StartLocation, ec.CurrentBranching);
ArrayList new_statements = new ArrayList ();
bool unreachable = false, warning_shown = false;
foreach (Statement s in statements){
if (unreachable && !(s is LabeledStatement)) {
if (!warning_shown && !(s is EmptyStatement)) {
warning_shown = true;
Warning_DeadCodeFound (s.loc);
}
continue;
}
if (s.Resolve (ec) == false) {
ok = false;
continue;
}
if (s is LabeledStatement)
unreachable = false;
else
unreachable = ec.CurrentBranching.CurrentUsageVector.IsUnreachable;
new_statements.Add (s);
}
statements = new_statements;
Report.Debug (1, "RESOLVE BLOCK DONE", StartLocation, ec.CurrentBranching);
FlowBranching.FlowReturns returns = ec.EndFlowBranching ();
ec.CurrentBlock = prev_block;
// If we're a non-static `struct' constructor which doesn't have an
// initializer, then we must initialize all of the struct's fields.
if ((this_variable != null) && (returns != FlowBranching.FlowReturns.Exception) &&
!this_variable.IsThisAssigned (ec, loc))
ok = false;
if ((labels != null) && (RootContext.WarningLevel >= 2)) {
foreach (LabeledStatement label in labels.Values)
if (!label.HasBeenReferenced)
Report.Warning (164, label.Location,
"This label has not been referenced");
}
Report.Debug (1, "RESOLVE BLOCK DONE #2", StartLocation, returns);
if ((returns == FlowBranching.FlowReturns.Always) ||
(returns == FlowBranching.FlowReturns.Exception) ||
(returns == FlowBranching.FlowReturns.Unreachable))
flags |= Flags.HasRet;
return ok;
}
protected override bool DoEmit (EmitContext ec)
{
foreach (Statement s in statements)
s.Emit (ec);
return (flags & Flags.HasRet) != 0;
}
public override bool Emit (EmitContext ec)
{
Block prev_block = ec.CurrentBlock;
ec.CurrentBlock = this;
bool emit_debug_info = (CodeGen.SymbolWriter != null);
bool is_lexical_block = !Implicit && (Parent != null);
if (emit_debug_info) {
if (is_lexical_block)
ec.ig.BeginScope ();
if (variables != null) {
foreach (DictionaryEntry de in variables) {
string name = (string) de.Key;
LocalInfo vi = (LocalInfo) de.Value;
if (vi.LocalBuilder == null)
continue;
vi.LocalBuilder.SetLocalSymInfo (name);
}
}
}
ec.Mark (StartLocation, true);
bool retval = DoEmit (ec);
ec.Mark (EndLocation, true);
if (emit_debug_info && is_lexical_block)
ec.ig.EndScope ();
ec.CurrentBlock = prev_block;
return retval;
}
}
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)){
Report.Error (150, loc, "A constant value is expected, got: " + e);
return false;
}
if (e is StringConstant || e is NullLiteral){
if (required_type == TypeManager.string_type){
converted = e;
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;
Expression new_expr;
//
// 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 = Convert.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 (System.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;
if (rgKeyBlocks.Count > 0) {
kbCurr = (KeyBlock) rgKeyBlocks [0];
foreach (object key in rgKeys)
{
bool fNextBlock = (key is UInt64) ? (ulong) key > (ulong) kbCurr.nLast :
System.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 = ig.DefineLabel ();
Type typeKeys = null;
if (rgKeys.Length > 0)
typeKeys = rgKeys [0].GetType (); // used for conversions
Type compare_type;
if (TypeManager.IsEnumType (SwitchType))
compare_type = TypeManager.EnumToUnderlying (SwitchType);
else
compare_type = SwitchType;
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 (compare_type == TypeManager.int64_type ||
compare_type == TypeManager.uint64_type)
{
// TODO: optimize constant/I4 cases
// check block range (could be > 2^31)
ig.Emit (OpCodes.Ldloc, val);
EmitObjectInteger (ig, System.Convert.ChangeType (kb.nFirst, typeKeys));
ig.Emit (OpCodes.Blt, lblDefault);
ig.Emit (OpCodes.Ldloc, val);
EmitObjectInteger (ig, System.Convert.ChangeType (kb.nLast, typeKeys));
ig.Emit (OpCodes.Bgt, lblDefault);
// normalize range
ig.Emit (OpCodes.Ldloc, val);
if (kb.nFirst != 0)
{
EmitObjectInteger (ig, System.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 (System.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;
}
}
bool returns = ss.Block.Emit (ec);
fAllReturn &= returns;
//ig.Emit (OpCodes.Br, lblEnd);
}
if (!fFoundDefault) {
ig.MarkLabel (lblDefault);
fAllReturn = false;
}
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 null_found;
ig.Emit (OpCodes.Ldloc, val);
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);
int section_count = Sections.Count;
for (int section = 0; section < section_count; section++){
SwitchSection ss = (SwitchSection) Sections [section];
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;
for (int label = 0; label < label_count; label++){
SwitchLabel sl = (SwitchLabel) ss.Labels [label];
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;
}
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 {
if (label+1 == label_count)
ig.Emit (OpCodes.Bne_Un, next_test);
else
ig.Emit (OpCodes.Beq, sec_begin);
}
}
}
if (null_found)
ig.MarkLabel (null_target);
ig.MarkLabel (sec_begin);
foreach (SwitchLabel sl in ss.Labels)
ig.MarkLabel (sl.ILLabelCode);
bool returns = ss.Block.Emit (ec);
if (returns)
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)
{
Expr = Expr.Resolve (ec);
if (Expr == null)
return false;
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;
Switch old_switch = ec.Switch;
ec.Switch = this;
ec.Switch.SwitchType = SwitchType;
ec.StartFlowBranching (FlowBranching.BranchingType.Switch, loc);
bool first = true;
foreach (SwitchSection ss in Sections){
if (!first)
ec.CurrentBranching.CreateSibling (FlowBranching.SiblingType.SwitchSection);
else
first = false;
if (ss.Block.Resolve (ec) != true)
return false;
}
if (!got_default)
ec.CurrentBranching.CreateSibling (FlowBranching.SiblingType.SwitchSection);
ec.EndFlowBranching ();
ec.Switch = old_switch;
return true;
}
protected override bool DoEmit (EmitContext ec)
{
// 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;
}
protected override bool DoEmit (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;
b.Unchecked = true;
}
public override bool Resolve (EmitContext ec)
{
bool previous_state = ec.CheckState;
bool previous_state_const = ec.ConstantCheckState;
ec.CheckState = false;
ec.ConstantCheckState = false;
bool ret = Block.Resolve (ec);
ec.CheckState = previous_state;
ec.ConstantCheckState = previous_state_const;
return ret;
}
protected override bool DoEmit (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;
b.Unchecked = false;
}
public override bool Resolve (EmitContext ec)
{
bool previous_state = ec.CheckState;
bool previous_state_const = ec.ConstantCheckState;
ec.CheckState = true;
ec.ConstantCheckState = true;
bool ret = Block.Resolve (ec);
ec.CheckState = previous_state;
ec.ConstantCheckState = previous_state_const;
return ret;
}
protected override bool DoEmit (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)
{
bool previous_state = ec.InUnsafe;
bool val;
ec.InUnsafe = true;
val = Block.Resolve (ec);
ec.InUnsafe = previous_state;
return val;
}
protected override bool DoEmit (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 {
Expression type;
ArrayList declarators;
Statement statement;
Type expr_type;
FixedData[] data;
struct FixedData {
public bool is_object;
public LocalInfo vi;
public Expression expr;
public Expression converted;
}
public Fixed (Expression type, ArrayList decls, Statement stmt, Location l)
{
this.type = type;
declarators = decls;
statement = stmt;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
if (!ec.InUnsafe){
Expression.UnsafeError (loc);
return false;
}
expr_type = ec.DeclSpace.ResolveType (type, false, loc);
if (expr_type == null)
return false;
if (ec.RemapToProxy){
Report.Error (-210, loc, "Fixed statement not allowed in iterators");
return false;
}
data = new FixedData [declarators.Count];
if (!expr_type.IsPointer){
Report.Error (209, loc, "Variables in a fixed statement must be pointers");
return false;
}
int i = 0;
foreach (Pair p in declarators){
LocalInfo vi = (LocalInfo) p.First;
Expression e = (Expression) p.Second;
vi.VariableInfo = null;
vi.ReadOnly = true;
//
// 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)");
return false;
}
ec.InFixedInitializer = true;
e = e.Resolve (ec);
ec.InFixedInitializer = false;
if (e == null)
return false;
child = ((Unary) e).Expr;
if (!TypeManager.VerifyUnManaged (child.Type, loc))
return false;
data [i].is_object = true;
data [i].expr = e;
data [i].converted = null;
data [i].vi = vi;
i++;
continue;
}
ec.InFixedInitializer = true;
e = e.Resolve (ec);
ec.InFixedInitializer = false;
if (e == null)
return false;
//
// Case 2: Array
//
if (e.Type.IsArray){
Type array_type = TypeManager.GetElementType (e.Type);
vi.MakePinned ();
//
// Provided that array_type is unmanaged,
//
if (!TypeManager.VerifyUnManaged (array_type, loc))
return false;
//
// and T* is implicitly convertible to the
// pointer type given in the fixed statement.
//
ArrayPtr array_ptr = new ArrayPtr (e, loc);
Expression converted = Convert.ImplicitConversionRequired (
ec, array_ptr, vi.VariableType, loc);
if (converted == null)
return false;
data [i].is_object = false;
data [i].expr = e;
data [i].converted = converted;
data [i].vi = vi;
i++;
continue;
}
//
// Case 3: string
//
if (e.Type == TypeManager.string_type){
data [i].is_object = false;
data [i].expr = e;
data [i].converted = null;
data [i].vi = vi;
i++;
}
}
return statement.Resolve (ec);
}
protected override bool DoEmit (EmitContext ec)
{
ILGenerator ig = ec.ig;
bool is_ret = false;
LocalBuilder [] clear_list = new LocalBuilder [data.Length];
for (int i = 0; i < data.Length; i++) {
LocalInfo vi = data [i].vi;
//
// Case 1: & object.
//
if (data [i].is_object) {
//
// Store pointer in pinned location
//
data [i].expr.Emit (ec);
ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
clear_list [i] = vi.LocalBuilder;
continue;
}
//
// Case 2: Array
//
if (data [i].expr.Type.IsArray){
//
// Store pointer in pinned location
//
data [i].converted.Emit (ec);
ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
clear_list [i] = vi.LocalBuilder;
continue;
}
//
// Case 3: string
//
if (data [i].expr.Type == TypeManager.string_type){
LocalBuilder pinned_string = ig.DeclareLocal (TypeManager.string_type);
TypeManager.MakePinned (pinned_string);
clear_list [i] = pinned_string;
data [i].expr.Emit (ec);
ig.Emit (OpCodes.Stloc, pinned_string);
Expression sptr = new StringPtr (pinned_string, loc);
Expression converted = Convert.ImplicitConversionRequired (
ec, sptr, vi.VariableType, loc);
if (converted == null)
continue;
converted.Emit (ec);
ig.Emit (OpCodes.Stloc, vi.LocalBuilder);
}
}
is_ret = statement.Emit (ec);
if (is_ret)
return is_ret;
//
// Clear the pinned variable
//
for (int i = 0; i < data.Length; i++) {
LocalInfo vi = data [i].vi;
if (data [i].is_object || data [i].expr.Type.IsArray) {
ig.Emit (OpCodes.Ldc_I4_0);
ig.Emit (OpCodes.Conv_U);
ig.Emit (OpCodes.Stloc, clear_list [i]);
} else if (data [i].expr.Type == TypeManager.string_type){
ig.Emit (OpCodes.Ldnull);
ig.Emit (OpCodes.Stloc, clear_list [i]);
}
}
return is_ret;
}
}
public class Catch {
public readonly string Name;
public readonly Block Block;
public readonly Location Location;
Expression type_expr;
Type type;
public Catch (Expression type, string name, Block block, Location l)
{
type_expr = type;
Name = name;
Block = block;
Location = l;
}
public Type CatchType {
get {
return type;
}
}
public bool IsGeneral {
get {
return type_expr == null;
}
}
public bool Resolve (EmitContext ec)
{
if (type_expr != null) {
type = ec.DeclSpace.ResolveType (type_expr, false, Location);
if (type == null)
return false;
if (type != TypeManager.exception_type && !type.IsSubclassOf (TypeManager.exception_type)){
Report.Error (155, Location,
"The type caught or thrown must be derived " +
"from System.Exception");
return false;
}
} else
type = null;
if (!Block.Resolve (ec))
return false;
return true;
}
}
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, Location l)
{
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;
loc = l;
}
public override bool Resolve (EmitContext ec)
{
bool ok = true;
ec.StartFlowBranching (FlowBranching.BranchingType.Exception, Block.StartLocation);
Report.Debug (1, "START OF TRY BLOCK", Block.StartLocation);
bool old_in_try = ec.InTry;
ec.InTry = true;
if (!Block.Resolve (ec))
ok = false;
ec.InTry = old_in_try;
FlowBranching.UsageVector vector = ec.CurrentBranching.CurrentUsageVector;
Report.Debug (1, "START OF CATCH BLOCKS", vector);
foreach (Catch c in Specific){
ec.CurrentBranching.CreateSibling (FlowBranching.SiblingType.Catch);
Report.Debug (1, "STARTED SIBLING FOR CATCH", ec.CurrentBranching);
if (c.Name != null) {
LocalInfo vi = c.Block.GetLocalInfo (c.Name);
if (vi == null)
throw new Exception ();
vi.VariableInfo = null;
}
bool old_in_catch = ec.InCatch;
ec.InCatch = true;
if (!c.Resolve (ec))
ok = false;
ec.InCatch = old_in_catch;
}
Report.Debug (1, "END OF CATCH BLOCKS", ec.CurrentBranching);
if (General != null){
ec.CurrentBranching.CreateSibling (FlowBranching.SiblingType.Catch);
Report.Debug (1, "STARTED SIBLING FOR GENERAL", ec.CurrentBranching);
bool old_in_catch = ec.InCatch;
ec.InCatch = true;
if (!General.Resolve (ec))
ok = false;
ec.InCatch = old_in_catch;
}
Report.Debug (1, "END OF GENERAL CATCH BLOCKS", ec.CurrentBranching);
if (Fini != null) {
if (ok)
ec.CurrentBranching.CreateSibling (FlowBranching.SiblingType.Finally);
Report.Debug (1, "STARTED SIBLING FOR FINALLY", ec.CurrentBranching, vector);
bool old_in_finally = ec.InFinally;
ec.InFinally = true;
if (!Fini.Resolve (ec))
ok = false;
ec.InFinally = old_in_finally;
}
FlowBranching.FlowReturns returns = ec.EndFlowBranching ();
FlowBranching.UsageVector f_vector = ec.CurrentBranching.CurrentUsageVector;
Report.Debug (1, "END OF TRY", ec.CurrentBranching, returns, vector, f_vector);
if (returns != FlowBranching.FlowReturns.Always) {
// Unfortunately, System.Reflection.Emit automatically emits a leave
// to the end of the finally block. This is a problem if `returns'
// is true since we may jump to a point after the end of the method.
// As a workaround, emit an explicit ret here.
ec.NeedExplicitReturn = true;
}
return ok;
}
protected override bool DoEmit (EmitContext ec)
{
ILGenerator ig = ec.ig;
Label end;
Label finish = ig.DefineLabel ();;
bool returns;
ec.TryCatchLevel++;
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){
LocalInfo vi;
ig.BeginCatchBlock (c.CatchType);
if (c.Name != null){
vi = c.Block.GetLocalInfo (c.Name);
if (vi == null)
throw new Exception ("Variable does not exist in this block");
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 ();
ec.TryCatchLevel--;
return returns;
}
}
public class Using : Statement {
object expression_or_block;
Statement Statement;
ArrayList var_list;
Expression expr;
Type expr_type;
Expression conv;
Expression [] converted_vars;
ExpressionStatement [] assign;
public Using (object expression_or_block, Statement stmt, Location l)
{
this.expression_or_block = expression_or_block;
Statement = stmt;
loc = l;
}
//
// Resolves for the case of using using a local variable declaration.
//
bool ResolveLocalVariableDecls (EmitContext ec)
{
bool need_conv = false;
expr_type = ec.DeclSpace.ResolveType (expr, false, loc);
int i = 0;
if (expr_type == null)
return false;
//
// The type must be an IDisposable or an implicit conversion
// must exist.
//
converted_vars = new Expression [var_list.Count];
assign = new ExpressionStatement [var_list.Count];
if (!TypeManager.ImplementsInterface (expr_type, TypeManager.idisposable_type)){
foreach (DictionaryEntry e in var_list){
Expression var = (Expression) e.Key;
var = var.ResolveLValue (ec, new EmptyExpression ());
if (var == null)
return false;
converted_vars [i] = Convert.ImplicitConversionRequired (
ec, var, TypeManager.idisposable_type, loc);
if (converted_vars [i] == null)
return false;
i++;
}
need_conv = true;
}
i = 0;
foreach (DictionaryEntry e in var_list){
LocalVariableReference var = (LocalVariableReference) e.Key;
Expression new_expr = (Expression) e.Value;
Expression a;
a = new Assign (var, new_expr, loc);
a = a.Resolve (ec);
if (a == null)
return false;
if (!need_conv)
converted_vars [i] = var;
assign [i] = (ExpressionStatement) a;
i++;
}
return true;
}
bool ResolveExpression (EmitContext ec)
{
if (!TypeManager.ImplementsInterface (expr_type, TypeManager.idisposable_type)){
conv = Convert.ImplicitConversionRequired (
ec, expr, TypeManager.idisposable_type, loc);
if (conv == null)
return false;
}
return true;
}
//
// Emits the code for the case of using using a local variable declaration.
//
bool EmitLocalVariableDecls (EmitContext ec)
{
ILGenerator ig = ec.ig;
int i = 0;
bool old_in_try = ec.InTry;
ec.InTry = true;
for (i = 0; i < assign.Length; i++) {
assign [i].EmitStatement (ec);
ig.BeginExceptionBlock ();
}
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)
{
//
// 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)
{
if (expression_or_block is DictionaryEntry){
expr = (Expression) ((DictionaryEntry) expression_or_block).Key;
var_list = (ArrayList)((DictionaryEntry)expression_or_block).Value;
if (!ResolveLocalVariableDecls (ec))
return false;
} else if (expression_or_block is Expression){
expr = (Expression) expression_or_block;
expr = expr.Resolve (ec);
if (expr == null)
return false;
expr_type = expr.Type;
if (!ResolveExpression (ec))
return false;
}
ec.StartFlowBranching (FlowBranching.BranchingType.Block, loc);
bool ok = Statement.Resolve (ec);
if (!ok) {
ec.KillFlowBranching ();
return false;
}
FlowBranching.FlowReturns returns = ec.EndFlowBranching ();
if (returns != FlowBranching.FlowReturns.Always) {
// Unfortunately, System.Reflection.Emit automatically emits a leave
// to the end of the finally block. This is a problem if `returns'
// is true since we may jump to a point after the end of the method.
// As a workaround, emit an explicit ret here.
ec.NeedExplicitReturn = true;
}
return true;
}
protected override bool DoEmit (EmitContext ec)
{
if (expression_or_block is DictionaryEntry)
return EmitLocalVariableDecls (ec);
else if (expression_or_block is Expression)
return EmitExpression (ec);
return false;
}
}
///
/// Implementation of the foreach C# statement
///
public class Foreach : Statement {
Expression type;
Expression variable;
Expression expr;
Statement statement;
ForeachHelperMethods hm;
Expression empty, conv;
Type array_type, element_type;
Type var_type;
public Foreach (Expression 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);
if (expr == null)
return false;
var_type = ec.DeclSpace.ResolveType (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 || expr.eclass == ExprClass.IndexerAccess)){
error1579 (expr.Type);
return false;
}
if (expr.Type.IsArray) {
array_type = expr.Type;
element_type = TypeManager.GetElementType (array_type);
empty = new EmptyExpression (element_type);
} else {
hm = ProbeCollectionType (ec, expr.Type);
if (hm == null){
error1579 (expr.Type);
return false;
}
array_type = expr.Type;
element_type = hm.element_type;
empty = new EmptyExpression (hm.element_type);
}
ec.StartFlowBranching (FlowBranching.BranchingType.LoopBlock, loc);
ec.CurrentBranching.CreateSibling (FlowBranching.SiblingType.Conditional);
//
//
// 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 = Convert.ExplicitConversion (ec, empty, var_type, loc);
if (conv == null)
return false;
variable = variable.ResolveLValue (ec, empty);
if (variable == null)
return false;
if (!statement.Resolve (ec))
return false;
FlowBranching.FlowReturns returns = ec.EndFlowBranching ();
return true;
}
//
// Retrieves a `public bool MoveNext ()' method from the Type `t'
//
static MethodInfo FetchMethodMoveNext (Type t)
{
MemberList move_next_list;
move_next_list = TypeContainer.FindMembers (
t, MemberTypes.Method,
BindingFlags.Public | BindingFlags.Instance,
Type.FilterName, "MoveNext");
if (move_next_list.Count == 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)
{
MemberList move_next_list;
move_next_list = TypeContainer.FindMembers (
t, MemberTypes.Method,
BindingFlags.Public | BindingFlags.Instance,
Type.FilterName, "get_Current");
if (move_next_list.Count == 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 Type element_type;
public Type enumerator_type;
public bool is_disposable;
public ForeachHelperMethods (EmitContext ec)
{
this.ec = ec;
this.element_type = TypeManager.object_type;
this.enumerator_type = TypeManager.ienumerator_type;
this.is_disposable = true;
}
}
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;
}
if ((mi.ReturnType == TypeManager.ienumerator_type) && (declaring == TypeManager.string_type))
//
// Apply the same optimization as MS: skip the GetEnumerator
// returning an IEnumerator, and use the one returning a
// CharEnumerator instead. This allows us to avoid the
// try-finally block and the boxing.
//
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) ||
(!RootContext.StdLib && TypeManager.ImplementsInterface (mi.ReturnType, TypeManager.ienumerator_type))) {
if (declaring != TypeManager.string_type) {
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;
hm.element_type = hm.get_current.ReturnType;
hm.enumerator_type = return_type;
hm.is_disposable = !hm.enumerator_type.IsSealed ||
TypeManager.ImplementsInterface (
hm.enumerator_type, TypeManager.idisposable_type);
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)
{
MemberList mi;
mi = TypeContainer.FindMembers (t, MemberTypes.Method,
BindingFlags.Public | BindingFlags.NonPublic |
BindingFlags.Instance,
FilterEnumerator, hm);
if (mi.Count == 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)
{
ILGenerator ig = ec.ig;
VariableStorage enumerator, disposable;
enumerator = new VariableStorage (ec, hm.enumerator_type);
if (hm.is_disposable)
disposable = new VariableStorage (ec, TypeManager.idisposable_type);
else
disposable = null;
enumerator.EmitThis ();
//
// 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);
}
enumerator.EmitStore ();
//
// Protect the code in a try/finalize block, so that
// if the beast implement IDisposable, we get rid of it
//
Label l;
bool old_in_try = ec.InTry;
if (hm.is_disposable) {
l = ig.BeginExceptionBlock ();
ec.InTry = true;
}
Label end_try = ig.DefineLabel ();
ig.MarkLabel (ec.LoopBegin);
enumerator.EmitLoad ();
ig.Emit (OpCodes.Callvirt, hm.move_next);
ig.Emit (OpCodes.Brfalse, end_try);
if (ec.InIterator)
ec.EmitThis ();
enumerator.EmitLoad ();
ig.Emit (OpCodes.Callvirt, hm.get_current);
if (ec.InIterator){
conv.Emit (ec);
ig.Emit (OpCodes.Stfld, ((FieldExpr) variable).FieldInfo);
} else
((IAssignMethod)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
//
if (hm.is_disposable) {
Label end_finally = ig.DefineLabel ();
bool old_in_finally = ec.InFinally;
ec.InFinally = true;
ig.BeginFinallyBlock ();
disposable.EmitThis ();
enumerator.EmitThis ();
enumerator.EmitLoad ();
ig.Emit (OpCodes.Isinst, TypeManager.idisposable_type);
disposable.EmitStore ();
disposable.EmitLoad ();
ig.Emit (OpCodes.Brfalse, end_finally);
disposable.EmitThis ();
disposable.EmitLoad ();
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)
{
int rank = array_type.GetArrayRank ();
ILGenerator ig = ec.ig;
VariableStorage copy = new VariableStorage (ec, array_type);
//
// Make our copy of the array
//
copy.EmitThis ();
expr.Emit (ec);
copy.EmitStore ();
if (rank == 1){
VariableStorage counter = new VariableStorage (ec,TypeManager.int32_type);
Label loop, test;
counter.EmitThis ();
ig.Emit (OpCodes.Ldc_I4_0);
counter.EmitStore ();
test = ig.DefineLabel ();
ig.Emit (OpCodes.Br, test);
loop = ig.DefineLabel ();
ig.MarkLabel (loop);
if (ec.InIterator)
ec.EmitThis ();
copy.EmitThis ();
copy.EmitLoad ();
counter.EmitThis ();
counter.EmitLoad ();
//
// Load the value, we load the value using the underlying type,
// then we use the variable.EmitAssign to load using the proper cast.
//
ArrayAccess.EmitLoadOpcode (ig, element_type);
if (ec.InIterator){
conv.Emit (ec);
ig.Emit (OpCodes.Stfld, ((FieldExpr) variable).FieldInfo);
} else
((IAssignMethod)variable).EmitAssign (ec, conv);
statement.Emit (ec);
ig.MarkLabel (ec.LoopBegin);
counter.EmitThis ();
counter.EmitThis ();
counter.EmitLoad ();
ig.Emit (OpCodes.Ldc_I4_1);
ig.Emit (OpCodes.Add);
counter.EmitStore ();
ig.MarkLabel (test);
counter.EmitThis ();
counter.EmitLoad ();
copy.EmitThis ();
copy.EmitLoad ();
ig.Emit (OpCodes.Ldlen);
ig.Emit (OpCodes.Conv_I4);
ig.Emit (OpCodes.Blt, loop);
} else {
VariableStorage [] dim_len = new VariableStorage [rank];
VariableStorage [] dim_count = new VariableStorage [rank];
Label [] loop = new Label [rank];
Label [] test = new Label [rank];
int dim;
for (dim = 0; dim < rank; dim++){
dim_len [dim] = new VariableStorage (ec, TypeManager.int32_type);
dim_count [dim] = new VariableStorage (ec, TypeManager.int32_type);
test [dim] = ig.DefineLabel ();
loop [dim] = ig.DefineLabel ();
}
for (dim = 0; dim < rank; dim++){
dim_len [dim].EmitThis ();
copy.EmitThis ();
copy.EmitLoad ();
IntLiteral.EmitInt (ig, dim);
ig.Emit (OpCodes.Callvirt, TypeManager.int_getlength_int);
dim_len [dim].EmitStore ();
}
for (dim = 0; dim < rank; dim++){
dim_count [dim].EmitThis ();
ig.Emit (OpCodes.Ldc_I4_0);
dim_count [dim].EmitStore ();
ig.Emit (OpCodes.Br, test [dim]);
ig.MarkLabel (loop [dim]);
}
if (ec.InIterator)
ec.EmitThis ();
copy.EmitThis ();
copy.EmitLoad ();
for (dim = 0; dim < rank; dim++){
dim_count [dim].EmitThis ();
dim_count [dim].EmitLoad ();
}
//
// 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);
if (ec.InIterator){
conv.Emit (ec);
ig.Emit (OpCodes.Stfld, ((FieldExpr) variable).FieldInfo);
} else
((IAssignMethod)variable).EmitAssign (ec, conv);
statement.Emit (ec);
ig.MarkLabel (ec.LoopBegin);
for (dim = rank - 1; dim >= 0; dim--){
dim_count [dim].EmitThis ();
dim_count [dim].EmitThis ();
dim_count [dim].EmitLoad ();
ig.Emit (OpCodes.Ldc_I4_1);
ig.Emit (OpCodes.Add);
dim_count [dim].EmitStore ();
ig.MarkLabel (test [dim]);
dim_count [dim].EmitThis ();
dim_count [dim].EmitLoad ();
dim_len [dim].EmitThis ();
dim_len [dim].EmitLoad ();
ig.Emit (OpCodes.Blt, loop [dim]);
}
}
ig.MarkLabel (ec.LoopEnd);
return false;
}
protected override bool DoEmit (EmitContext ec)
{
bool ret_val;
ILGenerator ig = ec.ig;
Label old_begin = ec.LoopBegin, old_end = ec.LoopEnd;
bool old_inloop = ec.InLoop;
int old_loop_begin_try_catch_level = ec.LoopBeginTryCatchLevel;
ec.LoopBegin = ig.DefineLabel ();
ec.LoopEnd = ig.DefineLabel ();
ec.InLoop = true;
ec.LoopBeginTryCatchLevel = ec.TryCatchLevel;
if (hm != null)
ret_val = EmitCollectionForeach (ec);
else
ret_val = EmitArrayForeach (ec);
ec.LoopBegin = old_begin;
ec.LoopEnd = old_end;
ec.InLoop = old_inloop;
ec.LoopBeginTryCatchLevel = old_loop_begin_try_catch_level;
return ret_val;
}
}
}