//
// statement.cs: Statement representation for the IL tree.
//
// Author:
// Miguel de Icaza (miguel@ximian.com)
// Martin Baulig (martin@gnome.org)
//
// (C) 2001, 2002 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.
///
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;
}
///
/// 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;
}
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)
{
Report.Debug (1, "START IF BLOCK", loc);
expr = ResolveBoolean (ec, expr, loc);
if (expr == null){
return false;
}
ec.StartFlowBranching (FlowBranchingType.BLOCK, loc);
if (!TrueStatement.Resolve (ec)) {
ec.KillFlowBranching ();
return false;
}
ec.CurrentBranching.CreateSibling ();
if ((FalseStatement != null) && !FalseStatement.Resolve (ec)) {
ec.KillFlowBranching ();
return false;
}
ec.EndFlowBranching ();
Report.Debug (1, "END IF BLOCK", loc);
return true;
}
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)
{
bool ok = true;
ec.StartFlowBranching (FlowBranchingType.LOOP_BLOCK, loc);
if (!EmbeddedStatement.Resolve (ec))
ok = false;
ec.EndFlowBranching ();
expr = ResolveBoolean (ec, expr, loc);
if (expr == null)
ok = false;
return ok;
}
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;
bool old_breaks = ec.Breaks;
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);
ec.Breaks = false;
EmbeddedStatement.Emit (ec);
bool breaks = ec.Breaks;
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;
ec.Breaks = old_breaks;
//
// Inform whether we are infinite or not
//
if (expr is BoolConstant){
BoolConstant bc = (BoolConstant) expr;
if (bc.Value == true)
return breaks == false;
}
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)
{
bool ok = true;
expr = ResolveBoolean (ec, expr, loc);
if (expr == null)
return false;
ec.StartFlowBranching (FlowBranchingType.LOOP_BLOCK, loc);
if (!Statement.Resolve (ec))
ok = false;
ec.EndFlowBranching ();
return 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;
bool old_breaks = ec.Breaks;
Label while_loop = ig.DefineLabel ();
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;
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 {
bool breaks;
ec.Breaks = false;
Statement.Emit (ec);
breaks = ec.Breaks;
ig.Emit (OpCodes.Br, ec.LoopBegin);
//
// Inform that we are infinite (ie, `we return'), only
// if we do not `break' inside the code.
//
ret = breaks == false;
}
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;
ec.Breaks = old_breaks;
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;
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 = ResolveBoolean (ec, Test, loc);
if (Test == null)
ok = false;
}
if (Increment != null){
if (!Increment.Resolve (ec))
ok = false;
}
ec.StartFlowBranching (FlowBranchingType.LOOP_BLOCK, loc);
if (!Statement.Resolve (ec))
ok = false;
ec.EndFlowBranching ();
return 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;
bool old_breaks = ec.Breaks;
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);
ec.Breaks = false;
Statement.Emit (ec);
bool breaks = ec.Breaks;
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)
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.Breaks = old_breaks;
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 breaks == false;
}
return false;
} else
return breaks == false;
}
}
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;
}
FlowBranching.UsageVector vector = ec.CurrentBranching.CurrentUsageVector;
if (ec.CurrentBranching.InTryBlock ())
ec.CurrentBranching.AddFinallyVector (vector);
else
vector.CheckOutParameters (ec.CurrentBranching);
vector.Returns = FlowReturns.ALWAYS;
vector.Breaks = FlowReturns.ALWAYS;
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 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 = Expression.ConvertImplicitRequired (
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);
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.CurrentUsageVector.Breaks = FlowReturns.ALWAYS;
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)
{
ec.Breaks = true;
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)
{
if (vectors != null)
ec.CurrentBranching.CurrentUsageVector.MergeJumpOrigins (vectors);
referenced = true;
return true;
}
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 Resolve (EmitContext ec)
{
ec.CurrentBranching.CurrentUsageVector.Breaks = FlowReturns.UNREACHABLE;
return true;
}
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.Breaks = true;
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");
}
label = sl.ILLabelCode;
ec.CurrentBranching.CurrentUsageVector.Breaks = FlowReturns.UNREACHABLE;
return true;
}
public override bool Emit (EmitContext ec)
{
ec.Breaks = true;
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.Error118 ("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.CurrentUsageVector.Breaks = FlowReturns.EXCEPTION;
return true;
}
public override bool Emit (EmitContext ec)
{
ec.Breaks = true;
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.CurrentUsageVector.Breaks = FlowReturns.ALWAYS;
return true;
}
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;
}
ec.Breaks = true;
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.CurrentUsageVector.Breaks = FlowReturns.ALWAYS;
return true;
}
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.Breaks = true;
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;
}
}
//
// This is used in the control flow analysis code to specify whether the
// current code block may return to its enclosing block before reaching
// its end.
//
public enum FlowReturns {
// It can never return.
NEVER,
// This means that the block contains a conditional return statement
// somewhere.
SOMETIMES,
// The code always returns, ie. there's an unconditional return / break
// statement in it.
ALWAYS,
// The code always throws an exception.
EXCEPTION,
// The current code block is unreachable. This happens if it's immediately
// following a FlowReturns.ALWAYS block.
UNREACHABLE
}
//
// This is a special bit vector which can inherit from another bit vector doing a
// copy-on-write strategy. The inherited vector may have a smaller size than the
// current one.
//
public class MyBitVector {
public readonly int Count;
public readonly MyBitVector InheritsFrom;
bool is_dirty;
BitArray vector;
public MyBitVector (int Count)
: this (null, Count)
{ }
public MyBitVector (MyBitVector InheritsFrom, int Count)
{
this.InheritsFrom = InheritsFrom;
this.Count = Count;
}
//
// Checks whether this bit vector has been modified. After setting this to true,
// we won't use the inherited vector anymore, but our own copy of it.
//
public bool IsDirty {
get {
return is_dirty;
}
set {
if (!is_dirty)
initialize_vector ();
}
}
//
// Get/set bit `index' in the bit vector.
//
public bool this [int index]
{
get {
if (index > Count)
throw new ArgumentOutOfRangeException ();
// We're doing a "copy-on-write" strategy here; as long
// as nobody writes to the array, we can use our parent's
// copy instead of duplicating the vector.
if (vector != null)
return vector [index];
else if (InheritsFrom != null) {
BitArray inherited = InheritsFrom.Vector;
if (index < inherited.Count)
return inherited [index];
else
return false;
} else
return false;
}
set {
if (index > Count)
throw new ArgumentOutOfRangeException ();
// Only copy the vector if we're actually modifying it.
if (this [index] != value) {
initialize_vector ();
vector [index] = value;
}
}
}
//
// If you explicitly convert the MyBitVector to a BitArray, you will get a deep
// copy of the bit vector.
//
public static explicit operator BitArray (MyBitVector vector)
{
vector.initialize_vector ();
return vector.Vector;
}
//
// Performs an `or' operation on the bit vector. The `new_vector' may have a
// different size than the current one.
//
public void Or (MyBitVector new_vector)
{
BitArray new_array = new_vector.Vector;
initialize_vector ();
int upper;
if (vector.Count < new_array.Count)
upper = vector.Count;
else
upper = new_array.Count;
for (int i = 0; i < upper; i++)
vector [i] = vector [i] | new_array [i];
}
//
// Perfonrms an `and' operation on the bit vector. The `new_vector' may have
// a different size than the current one.
//
public void And (MyBitVector new_vector)
{
BitArray new_array = new_vector.Vector;
initialize_vector ();
int lower, upper;
if (vector.Count < new_array.Count)
lower = upper = vector.Count;
else {
lower = new_array.Count;
upper = vector.Count;
}
for (int i = 0; i < lower; i++)
vector [i] = vector [i] & new_array [i];
for (int i = lower; i < upper; i++)
vector [i] = false;
}
//
// This does a deep copy of the bit vector.
//
public MyBitVector Clone ()
{
MyBitVector retval = new MyBitVector (Count);
retval.Vector = Vector;
return retval;
}
BitArray Vector {
get {
if (vector != null)
return vector;
else if (!is_dirty && (InheritsFrom != null))
return InheritsFrom.Vector;
initialize_vector ();
return vector;
}
set {
initialize_vector ();
for (int i = 0; i < Math.Min (vector.Count, value.Count); i++)
vector [i] = value [i];
}
}
void initialize_vector ()
{
if (vector != null)
return;
vector = new BitArray (Count, false);
if (InheritsFrom != null)
Vector = InheritsFrom.Vector;
is_dirty = true;
}
public override string ToString ()
{
StringBuilder sb = new StringBuilder ("MyBitVector (");
BitArray vector = Vector;
sb.Append (Count);
sb.Append (",");
if (!IsDirty)
sb.Append ("INHERITED - ");
for (int i = 0; i < vector.Count; i++) {
if (i > 0)
sb.Append (",");
sb.Append (vector [i]);
}
sb.Append (")");
return sb.ToString ();
}
}
//
// The type of a FlowBranching.
//
public enum FlowBranchingType {
// Normal (conditional or toplevel) block.
BLOCK,
// A loop block.
LOOP_BLOCK,
// Try/Catch block.
EXCEPTION,
// Switch block.
SWITCH,
// Switch section.
SWITCH_SECTION
}
//
// A new instance of this class is created every time a new block is resolved
// and if there's branching in the block's control flow.
//
public class FlowBranching {
//
// The type of this flow branching.
//
public readonly FlowBranchingType Type;
//
// The block this branching is contained in. This may be null if it's not
// a top-level block and it doesn't declare any local variables.
//
public readonly Block Block;
//
// The parent of this branching or null if this is the top-block.
//
public readonly FlowBranching Parent;
//
// Start-Location of this flow branching.
//
public readonly Location Location;
//
// A list of UsageVectors. A new vector is added each time control flow may
// take a different path.
//
public ArrayList Siblings;
//
// Private
//
InternalParameters param_info;
int[] param_map;
MyStructInfo[] struct_params;
int num_params;
ArrayList finally_vectors;
static int next_id = 0;
int id;
//
// Performs an `And' operation on the FlowReturns status
// (for instance, a block only returns ALWAYS if all its siblings
// always return).
//
public static FlowReturns AndFlowReturns (FlowReturns a, FlowReturns b)
{
if (b == FlowReturns.UNREACHABLE)
return a;
switch (a) {
case FlowReturns.NEVER:
if (b == FlowReturns.NEVER)
return FlowReturns.NEVER;
else
return FlowReturns.SOMETIMES;
case FlowReturns.SOMETIMES:
return FlowReturns.SOMETIMES;
case FlowReturns.ALWAYS:
if ((b == FlowReturns.ALWAYS) || (b == FlowReturns.EXCEPTION))
return FlowReturns.ALWAYS;
else
return FlowReturns.SOMETIMES;
case FlowReturns.EXCEPTION:
if (b == FlowReturns.EXCEPTION)
return FlowReturns.EXCEPTION;
else if (b == FlowReturns.ALWAYS)
return FlowReturns.ALWAYS;
else
return FlowReturns.SOMETIMES;
}
return b;
}
//
// The vector contains a BitArray with information about which local variables
// and parameters are already initialized at the current code position.
//
public class UsageVector {
//
// If this is true, then the usage vector has been modified and must be
// merged when we're done with this branching.
//
public bool IsDirty;
//
// The number of parameters in this block.
//
public readonly int CountParameters;
//
// The number of locals in this block.
//
public readonly int CountLocals;
//
// If not null, then we inherit our state from this vector and do a
// copy-on-write. If null, then we're the first sibling in a top-level
// block and inherit from the empty vector.
//
public readonly UsageVector InheritsFrom;
//
// Private.
//
MyBitVector locals, parameters;
FlowReturns real_returns, real_breaks;
bool breaks_set, is_finally;
static int next_id = 0;
int id;
//
// Normally, you should not use any of these constructors.
//
public UsageVector (UsageVector parent, int num_params, int num_locals)
{
this.InheritsFrom = parent;
this.CountParameters = num_params;
this.CountLocals = num_locals;
this.real_returns = FlowReturns.NEVER;
this.real_breaks = FlowReturns.NEVER;
if (parent != null) {
locals = new MyBitVector (parent.locals, CountLocals);
if (num_params > 0)
parameters = new MyBitVector (parent.parameters, num_params);
real_returns = parent.Returns;
real_breaks = parent.Breaks;
} else {
locals = new MyBitVector (null, CountLocals);
if (num_params > 0)
parameters = new MyBitVector (null, num_params);
}
id = ++next_id;
}
public UsageVector (UsageVector parent)
: this (parent, parent.CountParameters, parent.CountLocals)
{ }
//
// This does a deep copy of the usage vector.
//
public UsageVector Clone ()
{
UsageVector retval = new UsageVector (null, CountParameters, CountLocals);
retval.locals = locals.Clone ();
if (parameters != null)
retval.parameters = parameters.Clone ();
retval.real_returns = real_returns;
retval.real_breaks = real_breaks;
return retval;
}
//
// State of parameter `number'.
//
public bool this [int number]
{
get {
if (number == -1)
return true;
else if (number == 0)
throw new ArgumentException ();
return parameters [number - 1];
}
set {
if (number == -1)
return;
else if (number == 0)
throw new ArgumentException ();
parameters [number - 1] = value;
}
}
//
// State of the local variable `vi'.
// If the local variable is a struct, use a non-zero `field_idx'
// to check an individual field in it.
//
public bool this [VariableInfo vi, int field_idx]
{
get {
if (vi.Number == -1)
return true;
else if (vi.Number == 0)
throw new ArgumentException ();
return locals [vi.Number + field_idx - 1];
}
set {
if (vi.Number == -1)
return;
else if (vi.Number == 0)
throw new ArgumentException ();
locals [vi.Number + field_idx - 1] = value;
}
}
//
// Specifies when the current block returns.
//
public FlowReturns Returns {
get {
return real_returns;
}
set {
real_returns = value;
}
}
//
// Specifies whether control may return to our containing block
// before reaching the end of this block. This happens if there
// is a break/continue/goto/return in it.
//
public FlowReturns Breaks {
get {
return real_breaks;
}
set {
real_breaks = value;
breaks_set = true;
}
}
public bool AlwaysBreaks {
get {
return (Breaks == FlowReturns.ALWAYS) ||
(Breaks == FlowReturns.EXCEPTION) ||
(Breaks == FlowReturns.UNREACHABLE);
}
}
public bool MayBreak {
get {
return Breaks != FlowReturns.NEVER;
}
}
public bool AlwaysReturns {
get {
return Returns == FlowReturns.ALWAYS;
}
}
public bool MayReturn {
get {
return (Returns == FlowReturns.SOMETIMES) ||
(Returns == FlowReturns.ALWAYS);
}
}
//
// Merge a child branching.
//
public FlowReturns MergeChildren (FlowBranching branching, ICollection children)
{
MyBitVector new_locals = null;
MyBitVector new_params = null;
FlowReturns new_returns = FlowReturns.NEVER;
FlowReturns new_breaks = FlowReturns.NEVER;
bool new_returns_set = false, new_breaks_set = false;
Report.Debug (2, "MERGING CHILDREN", branching, branching.Type,
this, children.Count);
foreach (UsageVector child in children) {
Report.Debug (2, " MERGING CHILD", child, child.is_finally);
if (!child.is_finally) {
// If Returns is already set, perform an
// `And' operation on it, otherwise just set just.
if (!new_returns_set) {
new_returns = child.Returns;
new_returns_set = true;
} else
new_returns = AndFlowReturns (
new_returns, child.Returns);
// If Breaks is already set, perform an
// `And' operation on it, otherwise just set just.
if (!new_breaks_set) {
new_breaks = child.Breaks;
new_breaks_set = true;
} else
new_breaks = AndFlowReturns (
new_breaks, child.Breaks);
}
// Ignore unreachable children.
if (child.Returns == FlowReturns.UNREACHABLE)
continue;
// A local variable is initialized after a flow branching if it
// has been initialized in all its branches which do neither
// always return or always throw an exception.
//
// If a branch may return, but does not always return, then we
// can treat it like a never-returning branch here: control will
// only reach the code position after the branching if we did not
// return here.
//
// It's important to distinguish between always and sometimes
// returning branches here:
//
// 1 int a;
// 2 if (something) {
// 3 return;
// 4 a = 5;
// 5 }
// 6 Console.WriteLine (a);
//
// The if block in lines 3-4 always returns, so we must not look
// at the initialization of `a' in line 4 - thus it'll still be
// uninitialized in line 6.
//
// On the other hand, the following is allowed:
//
// 1 int a;
// 2 if (something)
// 3 a = 5;
// 4 else
// 5 return;
// 6 Console.WriteLine (a);
//
// Here, `a' is initialized in line 3 and we must not look at
// line 5 since it always returns.
//
if (child.is_finally) {
if (new_locals == null)
new_locals = locals.Clone ();
new_locals.Or (child.locals);
if (parameters != null) {
if (new_params == null)
new_params = parameters.Clone ();
new_params.Or (child.parameters);
}
} else {
if (!child.AlwaysReturns && !child.AlwaysBreaks) {
if (new_locals != null)
new_locals.And (child.locals);
else {
new_locals = locals.Clone ();
new_locals.Or (child.locals);
}
} else if (children.Count == 1) {
new_locals = locals.Clone ();
new_locals.Or (child.locals);
}
// An `out' parameter must be assigned in all branches which do
// not always throw an exception.
if (parameters != null) {
if (child.Breaks != FlowReturns.EXCEPTION) {
if (new_params != null)
new_params.And (child.parameters);
else {
new_params = parameters.Clone ();
new_params.Or (child.parameters);
}
} else if (children.Count == 1) {
new_params = parameters.Clone ();
new_params.Or (child.parameters);
}
}
}
}
Returns = new_returns;
if ((branching.Type == FlowBranchingType.BLOCK) ||
(branching.Type == FlowBranchingType.EXCEPTION) ||
(new_breaks == FlowReturns.UNREACHABLE) ||
(new_breaks == FlowReturns.EXCEPTION))
Breaks = new_breaks;
//
// We've now either reached the point after the branching or we will
// never get there since we always return or always throw an exception.
//
// If we can reach the point after the branching, mark all locals and
// parameters as initialized which have been initialized in all branches
// we need to look at (see above).
//
if (((new_breaks != FlowReturns.ALWAYS) &&
(new_breaks != FlowReturns.EXCEPTION) &&
(new_breaks != FlowReturns.UNREACHABLE)) ||
(children.Count == 1)) {
if (new_locals != null)
locals.Or (new_locals);
if (new_params != null)
parameters.Or (new_params);
}
Report.Debug (2, "MERGING CHILDREN DONE", branching.Type,
new_params, new_locals, new_returns, new_breaks, this);
if (branching.Type == FlowBranchingType.SWITCH_SECTION) {
if ((new_breaks != FlowReturns.ALWAYS) &&
(new_breaks != FlowReturns.EXCEPTION) &&
(new_breaks != FlowReturns.UNREACHABLE))
Report.Error (163, branching.Location,
"Control cannot fall through from one " +
"case label to another");
}
return new_returns;
}
//
// Tells control flow analysis that the current code position may be reached with
// a forward jump from any of the origins listed in `origin_vectors' which is a
// list of UsageVectors.
//
// This is used when resolving forward gotos - in the following example, the
// variable `a' is uninitialized in line 8 becase this line may be reached via
// the goto in line 4:
//
// 1 int a;
//
// 3 if (something)
// 4 goto World;
//
// 6 a = 5;
//
// 7 World:
// 8 Console.WriteLine (a);
//
//
public void MergeJumpOrigins (ICollection origin_vectors)
{
Report.Debug (1, "MERGING JUMP ORIGIN", this);
real_breaks = FlowReturns.NEVER;
breaks_set = false;
foreach (UsageVector vector in origin_vectors) {
Report.Debug (1, " MERGING JUMP ORIGIN", vector);
locals.And (vector.locals);
if (parameters != null)
parameters.And (vector.parameters);
Breaks = AndFlowReturns (Breaks, vector.Breaks);
}
Report.Debug (1, "MERGING JUMP ORIGIN DONE", this);
}
//
// This is used at the beginning of a finally block if there were
// any return statements in the try block or one of the catch blocks.
//
public void MergeFinallyOrigins (ICollection finally_vectors)
{
Report.Debug (1, "MERGING FINALLY ORIGIN", this);
real_breaks = FlowReturns.NEVER;
breaks_set = false;
foreach (UsageVector vector in finally_vectors) {
Report.Debug (1, " MERGING FINALLY ORIGIN", vector);
if (parameters != null)
parameters.And (vector.parameters);
Breaks = AndFlowReturns (Breaks, vector.Breaks);
}
is_finally = true;
Report.Debug (1, "MERGING FINALLY ORIGIN DONE", this);
}
public void CheckOutParameters (FlowBranching branching)
{
if (parameters != null)
branching.CheckOutParameters (parameters, branching.Location);
}
//
// Performs an `or' operation on the locals and the parameters.
//
public void Or (UsageVector new_vector)
{
locals.Or (new_vector.locals);
if (parameters != null)
parameters.Or (new_vector.parameters);
}
//
// Performs an `and' operation on the locals.
//
public void AndLocals (UsageVector new_vector)
{
locals.And (new_vector.locals);
}
//
// Returns a deep copy of the parameters.
//
public MyBitVector Parameters {
get {
if (parameters != null)
return parameters.Clone ();
else
return null;
}
}
//
// Returns a deep copy of the locals.
//
public MyBitVector Locals {
get {
return locals.Clone ();
}
}
//
// Debugging stuff.
//
public override string ToString ()
{
StringBuilder sb = new StringBuilder ();
sb.Append ("Vector (");
sb.Append (id);
sb.Append (",");
sb.Append (Returns);
sb.Append (",");
sb.Append (Breaks);
if (parameters != null) {
sb.Append (" - ");
sb.Append (parameters);
}
sb.Append (" - ");
sb.Append (locals);
sb.Append (")");
return sb.ToString ();
}
}
FlowBranching (FlowBranchingType type, Location loc)
{
this.Siblings = new ArrayList ();
this.Block = null;
this.Location = loc;
this.Type = type;
id = ++next_id;
}
//
// Creates a new flow branching for `block'.
// This is used from Block.Resolve to create the top-level branching of
// the block.
//
public FlowBranching (Block block, InternalParameters ip, Location loc)
: this (FlowBranchingType.BLOCK, loc)
{
Block = block;
Parent = null;
int count = (ip != null) ? ip.Count : 0;
param_info = ip;
param_map = new int [count];
struct_params = new MyStructInfo [count];
num_params = 0;
for (int i = 0; i < count; i++) {
Parameter.Modifier mod = param_info.ParameterModifier (i);
if ((mod & Parameter.Modifier.OUT) == 0)
continue;
param_map [i] = ++num_params;
Type param_type = param_info.ParameterType (i);
struct_params [i] = MyStructInfo.GetStructInfo (param_type);
if (struct_params [i] != null)
num_params += struct_params [i].Count;
}
Siblings = new ArrayList ();
Siblings.Add (new UsageVector (null, num_params, block.CountVariables));
}
//
// Creates a new flow branching which is contained in `parent'.
// You should only pass non-null for the `block' argument if this block
// introduces any new variables - in this case, we need to create a new
// usage vector with a different size than our parent's one.
//
public FlowBranching (FlowBranching parent, FlowBranchingType type,
Block block, Location loc)
: this (type, loc)
{
Parent = parent;
Block = block;
if (parent != null) {
param_info = parent.param_info;
param_map = parent.param_map;
struct_params = parent.struct_params;
num_params = parent.num_params;
}
UsageVector vector;
if (Block != null)
vector = new UsageVector (parent.CurrentUsageVector, num_params,
Block.CountVariables);
else
vector = new UsageVector (Parent.CurrentUsageVector);
Siblings.Add (vector);
switch (Type) {
case FlowBranchingType.EXCEPTION:
finally_vectors = new ArrayList ();
break;
default:
break;
}
}
//
// Returns the branching's current usage vector.
//
public UsageVector CurrentUsageVector
{
get {
return (UsageVector) Siblings [Siblings.Count - 1];
}
}
//
// Creates a sibling of the current usage vector.
//
public void CreateSibling ()
{
Siblings.Add (new UsageVector (Parent.CurrentUsageVector));
Report.Debug (1, "CREATED SIBLING", CurrentUsageVector);
}
//
// Creates a sibling for a `finally' block.
//
public void CreateSiblingForFinally ()
{
if (Type != FlowBranchingType.EXCEPTION)
throw new NotSupportedException ();
CreateSibling ();
CurrentUsageVector.MergeFinallyOrigins (finally_vectors);
}
//
// Check whether all `out' parameters have been assigned.
//
public void CheckOutParameters (MyBitVector parameters, Location loc)
{
if (InTryBlock ())
return;
for (int i = 0; i < param_map.Length; i++) {
int index = param_map [i];
if (index == 0)
continue;
if (parameters [index - 1])
continue;
// If it's a struct, we must ensure that all its fields have
// been assigned. If the struct has any non-public fields, this
// can only be done by assigning the whole struct.
MyStructInfo struct_info = struct_params [index - 1];
if ((struct_info == null) || struct_info.HasNonPublicFields) {
Report.Error (
177, loc, "The out parameter `" +
param_info.ParameterName (i) + "' must be " +
"assigned before control leave the current method.");
param_map [i] = 0;
continue;
}
for (int j = 0; j < struct_info.Count; j++) {
if (!parameters [index + j]) {
Report.Error (
177, loc, "The out parameter `" +
param_info.ParameterName (i) + "' must be " +
"assigned before control leave the current method.");
param_map [i] = 0;
break;
}
}
}
}
//
// Merge a child branching.
//
public FlowReturns MergeChild (FlowBranching child)
{
return CurrentUsageVector.MergeChildren (child, child.Siblings);
}
//
// Does the toplevel merging.
//
public FlowReturns MergeTopBlock ()
{
if ((Type != FlowBranchingType.BLOCK) || (Block == null))
throw new NotSupportedException ();
UsageVector vector = new UsageVector (null, num_params, Block.CountVariables);
Report.Debug (1, "MERGING TOP BLOCK", Location, vector);
vector.MergeChildren (this, Siblings);
Siblings.Clear ();
Siblings.Add (vector);
Report.Debug (1, "MERGING TOP BLOCK DONE", Location, vector);
if (vector.Breaks != FlowReturns.EXCEPTION) {
if (!vector.AlwaysBreaks)
CheckOutParameters (CurrentUsageVector.Parameters, Location);
return vector.AlwaysBreaks ? FlowReturns.ALWAYS : vector.Returns;
} else
return FlowReturns.EXCEPTION;
}
public bool InTryBlock ()
{
if (finally_vectors != null)
return true;
else if (Parent != null)
return Parent.InTryBlock ();
else
return false;
}
public void AddFinallyVector (UsageVector vector)
{
if (finally_vectors != null) {
finally_vectors.Add (vector.Clone ());
return;
}
if (Parent != null)
Parent.AddFinallyVector (vector);
else
throw new NotSupportedException ();
}
public bool IsVariableAssigned (VariableInfo vi)
{
if (CurrentUsageVector.AlwaysBreaks)
return true;
else
return CurrentUsageVector [vi, 0];
}
public bool IsVariableAssigned (VariableInfo vi, int field_idx)
{
if (CurrentUsageVector.AlwaysBreaks)
return true;
else
return CurrentUsageVector [vi, field_idx];
}
public void SetVariableAssigned (VariableInfo vi)
{
if (CurrentUsageVector.AlwaysBreaks)
return;
CurrentUsageVector [vi, 0] = true;
}
public void SetVariableAssigned (VariableInfo vi, int field_idx)
{
if (CurrentUsageVector.AlwaysBreaks)
return;
CurrentUsageVector [vi, field_idx] = true;
}
public bool IsParameterAssigned (int number)
{
int index = param_map [number];
if (index == 0)
return true;
if (CurrentUsageVector [index])
return true;
// Parameter is not assigned, so check whether it's a struct.
// If it's either not a struct or a struct which non-public
// fields, return false.
MyStructInfo struct_info = struct_params [number];
if ((struct_info == null) || struct_info.HasNonPublicFields)
return false;
// Ok, so each field must be assigned.
for (int i = 0; i < struct_info.Count; i++)
if (!CurrentUsageVector [index + i])
return false;
return true;
}
public bool IsParameterAssigned (int number, string field_name)
{
int index = param_map [number];
if (index == 0)
return true;
MyStructInfo info = (MyStructInfo) struct_params [number];
if (info == null)
return true;
int field_idx = info [field_name];
return CurrentUsageVector [index + field_idx];
}
public void SetParameterAssigned (int number)
{
if (param_map [number] == 0)
return;
if (!CurrentUsageVector.AlwaysBreaks)
CurrentUsageVector [param_map [number]] = true;
}
public void SetParameterAssigned (int number, string field_name)
{
int index = param_map [number];
if (index == 0)
return;
MyStructInfo info = (MyStructInfo) struct_params [number];
if (info == null)
return;
int field_idx = info [field_name];
if (!CurrentUsageVector.AlwaysBreaks)
CurrentUsageVector [index + field_idx] = true;
}
public override string ToString ()
{
StringBuilder sb = new StringBuilder ("FlowBranching (");
sb.Append (id);
sb.Append (",");
sb.Append (Type);
if (Block != null) {
sb.Append (" - ");
sb.Append (Block.ID);
sb.Append (" - ");
sb.Append (Block.StartLocation);
}
sb.Append (" - ");
sb.Append (Siblings.Count);
sb.Append (" - ");
sb.Append (CurrentUsageVector);
sb.Append (")");
return sb.ToString ();
}
}
public class MyStructInfo {
public readonly Type Type;
public readonly FieldInfo[] Fields;
public readonly FieldInfo[] NonPublicFields;
public readonly int Count;
public readonly int CountNonPublic;
public readonly bool HasNonPublicFields;
private static Hashtable field_type_hash = new Hashtable ();
private Hashtable field_hash;
// Private constructor. To save memory usage, we only need to create one instance
// of this class per struct type.
private MyStructInfo (Type type)
{
this.Type = type;
if (type is TypeBuilder) {
TypeContainer tc = TypeManager.LookupTypeContainer (type);
ArrayList fields = tc.Fields;
if (fields != null) {
foreach (Field field in fields) {
if ((field.ModFlags & Modifiers.STATIC) != 0)
continue;
if ((field.ModFlags & Modifiers.PUBLIC) != 0)
++Count;
else
++CountNonPublic;
}
}
Fields = new FieldInfo [Count];
NonPublicFields = new FieldInfo [CountNonPublic];
Count = CountNonPublic = 0;
if (fields != null) {
foreach (Field field in fields) {
if ((field.ModFlags & Modifiers.STATIC) != 0)
continue;
if ((field.ModFlags & Modifiers.PUBLIC) != 0)
Fields [Count++] = field.FieldBuilder;
else
NonPublicFields [CountNonPublic++] =
field.FieldBuilder;
}
}
} else {
Fields = type.GetFields (BindingFlags.Instance|BindingFlags.Public);
Count = Fields.Length;
NonPublicFields = type.GetFields (BindingFlags.Instance|BindingFlags.NonPublic);
CountNonPublic = NonPublicFields.Length;
}
Count += NonPublicFields.Length;
int number = 0;
field_hash = new Hashtable ();
foreach (FieldInfo field in Fields)
field_hash.Add (field.Name, ++number);
if (NonPublicFields.Length != 0)
HasNonPublicFields = true;
foreach (FieldInfo field in NonPublicFields)
field_hash.Add (field.Name, ++number);
}
public int this [string name] {
get {
if (field_hash.Contains (name))
return (int) field_hash [name];
else
return 0;
}
}
public FieldInfo this [int index] {
get {
if (index >= Fields.Length)
return NonPublicFields [index - Fields.Length];
else
return Fields [index];
}
}
public static MyStructInfo GetStructInfo (Type type)
{
if (!TypeManager.IsValueType (type) || TypeManager.IsEnumType (type))
return null;
if (!(type is TypeBuilder) && TypeManager.IsBuiltinType (type))
return null;
MyStructInfo info = (MyStructInfo) field_type_hash [type];
if (info != null)
return info;
info = new MyStructInfo (type);
field_type_hash.Add (type, info);
return info;
}
public static MyStructInfo GetStructInfo (TypeContainer tc)
{
MyStructInfo info = (MyStructInfo) field_type_hash [tc.TypeBuilder];
if (info != null)
return info;
info = new MyStructInfo (tc.TypeBuilder);
field_type_hash.Add (tc.TypeBuilder, info);
return info;
}
}
public class VariableInfo : IVariable {
public Expression Type;
public LocalBuilder LocalBuilder;
public Type VariableType;
public readonly string Name;
public readonly Location Location;
public readonly int Block;
public int Number;
public bool Used;
public bool Assigned;
public bool ReadOnly;
public VariableInfo (Expression type, string name, int block, Location l)
{
Type = type;
Name = name;
Block = block;
LocalBuilder = null;
Location = l;
}
public VariableInfo (TypeContainer tc, int block, Location l)
{
VariableType = tc.TypeBuilder;
struct_info = MyStructInfo.GetStructInfo (tc);
Block = block;
LocalBuilder = null;
Location = l;
}
MyStructInfo struct_info;
public MyStructInfo StructInfo {
get {
return struct_info;
}
}
public bool IsAssigned (EmitContext ec, Location loc)
{
if (!ec.DoFlowAnalysis || ec.CurrentBranching.IsVariableAssigned (this))
return true;
MyStructInfo struct_info = StructInfo;
if ((struct_info == null) || (struct_info.HasNonPublicFields && (Name != null))) {
Report.Error (165, loc, "Use of unassigned local variable `" + Name + "'");
ec.CurrentBranching.SetVariableAssigned (this);
return false;
}
int count = struct_info.Count;
for (int i = 0; i < count; i++) {
if (!ec.CurrentBranching.IsVariableAssigned (this, i+1)) {
if (Name != null) {
Report.Error (165, loc,
"Use of unassigned local variable `" +
Name + "'");
ec.CurrentBranching.SetVariableAssigned (this);
return false;
}
FieldInfo field = struct_info [i];
Report.Error (171, loc,
"Field `" + TypeManager.CSharpName (VariableType) +
"." + field.Name + "' must be fully initialized " +
"before control leaves the constructor");
return false;
}
}
return true;
}
public bool IsFieldAssigned (EmitContext ec, string name, Location loc)
{
if (!ec.DoFlowAnalysis || ec.CurrentBranching.IsVariableAssigned (this) ||
(struct_info == null))
return true;
int field_idx = StructInfo [name];
if (field_idx == 0)
return true;
if (!ec.CurrentBranching.IsVariableAssigned (this, field_idx)) {
Report.Error (170, loc,
"Use of possibly unassigned field `" + name + "'");
ec.CurrentBranching.SetVariableAssigned (this, field_idx);
return false;
}
return true;
}
public void SetAssigned (EmitContext ec)
{
if (ec.DoFlowAnalysis)
ec.CurrentBranching.SetVariableAssigned (this);
}
public void SetFieldAssigned (EmitContext ec, string name)
{
if (ec.DoFlowAnalysis && (struct_info != null))
ec.CurrentBranching.SetVariableAssigned (this, StructInfo [name]);
}
public bool Resolve (DeclSpace decl)
{
if (struct_info != null)
return true;
if (VariableType == null)
VariableType = decl.ResolveType (Type, false, Location);
if (VariableType == null)
return false;
struct_info = MyStructInfo.GetStructInfo (VariableType);
return true;
}
public void MakePinned ()
{
TypeManager.MakePinned (LocalBuilder);
}
public override string ToString ()
{
return "VariableInfo (" + Number + "," + Type + "," + Location + ")";
}
}
///
/// 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, bool implicit_block, Parameters parameters)
: this (parent, implicit_block, parameters, Location.Null, Location.Null)
{ }
public Block (Block parent, Location start, Location end)
: this (parent, false, start, end)
{ }
public Block (Block parent, Parameters parameters, Location start, Location end)
: this (parent, false, parameters, start, end)
{ }
public Block (Block parent, bool implicit_block, Location start, Location end)
: this (parent, implicit_block, Parameters.EmptyReadOnlyParameters,
start, end)
{ }
public Block (Block parent, bool implicit_block, Parameters parameters,
Location start, Location end)
{
if (parent != null)
parent.AddChild (this);
this.Parent = parent;
this.Implicit = implicit_block;
this.parameters = parameters;
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;
}
VariableInfo this_variable = null;
//
// Returns the "this" instance variable of this block.
// See AddThisVariable() for more information.
//
public VariableInfo 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);
}
foreach (Block child in block.children) {
if (child.Variables != null) {
foreach (string name in child.Variables.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 VariableInfo AddThisVariable (TypeContainer tc, Location l)
{
if (this_variable != null)
return this_variable;
this_variable = new VariableInfo (tc, ID, l);
if (variables == null)
variables = new Hashtable ();
variables.Add ("this", this_variable);
return this_variable;
}
public VariableInfo AddVariable (Expression type, string name, Parameters pars, Location l)
{
if (variables == null)
variables = new Hashtable ();
VariableInfo vi = GetVariableInfo (name);
if (vi != null) {
if (vi.Block != ID)
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 VariableInfo (type, name, ID, l);
variables.Add (name, vi);
if (variables_initialized)
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 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 Expression 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];
}
}
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);
used = true;
}
public bool Used {
get {
return used;
}
}
public void Use ()
{
used = true;
}
bool variables_initialized = false;
int count_variables = 0, first_variable = 0;
void UpdateVariableInfo (EmitContext ec)
{
DeclSpace ds = ec.DeclSpace;
first_variable = 0;
if (Parent != null)
first_variable += Parent.CountVariables;
count_variables = first_variable;
if (variables != null) {
foreach (VariableInfo vi in variables.Values) {
if (!vi.Resolve (ds)) {
vi.Number = -1;
continue;
}
vi.Number = ++count_variables;
if (vi.StructInfo != null)
count_variables += vi.StructInfo.Count;
}
}
variables_initialized = true;
}
//
//
// The number of local variables in this block
//
public int CountVariables
{
get {
if (!variables_initialized)
throw new Exception ();
return count_variables;
}
}
///
/// 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;
if (!variables_initialized)
UpdateVariableInfo (ec);
//
// 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;
if (vi.VariableType == null)
continue;
vi.LocalBuilder = ig.DeclareLocal (vi.VariableType);
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;
bool ok = true;
ec.CurrentBlock = this;
ec.StartFlowBranching (this);
Report.Debug (1, "RESOLVE BLOCK", StartLocation, ec.CurrentBranching);
if (!variables_initialized)
UpdateVariableInfo (ec);
foreach (Statement s in statements){
if (s.Resolve (ec) == false)
ok = false;
}
Report.Debug (1, "RESOLVE BLOCK DONE", StartLocation, ec.CurrentBranching);
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 != FlowReturns.EXCEPTION) &&
!this_variable.IsAssigned (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");
}
return ok;
}
public override bool Emit (EmitContext ec)
{
bool is_ret = false, this_ret = false;
Block prev_block = ec.CurrentBlock;
bool warning_shown = false;
ec.CurrentBlock = this;
if (CodeGen.SymbolWriter != null) {
ec.Mark (StartLocation);
foreach (Statement s in statements) {
ec.Mark (s.loc);
if (is_ret && !warning_shown && !(s is EmptyStatement)){
warning_shown = true;
Warning_DeadCodeFound (s.loc);
continue;
}
this_ret = s.Emit (ec);
if (this_ret)
is_ret = true;
}
ec.Mark (EndLocation);
} else {
foreach (Statement s in statements){
if (is_ret && !warning_shown && !(s is EmptyStatement)){
warning_shown = true;
Warning_DeadCodeFound (s.loc);
continue;
}
this_ret = s.Emit (ec);
if (this_ret)
is_ret = true;
}
}
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 = 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 = 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;
if (rgKeyBlocks.Count > 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 = ig.DefineLabel ();
Type typeKeys = null;
if (rgKeys.Length > 0)
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;
}
}
ec.Breaks = false;
bool returns = ss.Block.Emit (ec);
if (!ec.Breaks && !returns)
Report.Error (163, ((SwitchLabel) ss.Labels [0]).loc,
"Control cannot fall through from one " +
"case label to another");
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 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);
ec.Breaks = false;
bool returns = ss.Block.Emit (ec);
if (!ec.Breaks && !returns)
Report.Error (163, ((SwitchLabel) ss.Labels [0]).loc,
"Control cannot fall through from one " +
"case label to another");
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 (FlowBranchingType.SWITCH, loc);
bool first = true;
foreach (SwitchSection ss in Sections){
if (!first)
ec.CurrentBranching.CreateSibling ();
else
first = false;
if (ss.Block.Resolve (ec) != true)
return false;
}
if (!got_default)
ec.CurrentBranching.CreateSibling ();
ec.EndFlowBranching ();
ec.Switch = old_switch;
return true;
}
public override bool Emit (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;
}
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)
{
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;
}
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)
{
bool previous_state = ec.InUnsafe;
bool val;
ec.InUnsafe = true;
val = Block.Resolve (ec);
ec.InUnsafe = previous_state;
return val;
}
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 {
Expression type;
ArrayList declarators;
Statement statement;
Type expr_type;
FixedData[] data;
struct FixedData {
public bool is_object;
public VariableInfo 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)
{
expr_type = ec.DeclSpace.ResolveType (type, false, loc);
if (expr_type == null)
return false;
data = new FixedData [declarators.Count];
int i = 0;
foreach (Pair p in declarators){
VariableInfo vi = (VariableInfo) p.First;
Expression e = (Expression) p.Second;
vi.Number = -1;
//
// 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;
}
e = e.Resolve (ec);
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;
}
e = e.Resolve (ec);
if (e == null)
return false;
//
// 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))
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 = Expression.ConvertImplicitRequired (
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);
}
public override bool Emit (EmitContext ec)
{
ILGenerator ig = ec.ig;
bool is_ret = false;
for (int i = 0; i < data.Length; i++) {
VariableInfo 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);
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 2: Array
//
if (data [i].expr.Type.IsArray){
//
// Store pointer in pinned location
//
data [i].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 (data [i].expr.Type == TypeManager.string_type){
LocalBuilder pinned_string = ig.DeclareLocal (TypeManager.string_type);
TypeManager.MakePinned (pinned_string);
data [i].expr.Emit (ec);
ig.Emit (OpCodes.Stloc, pinned_string);
Expression sptr = new StringPtr (pinned_string, loc);
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 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 (FlowBranchingType.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 ();
Report.Debug (1, "STARTED SIBLING FOR CATCH", ec.CurrentBranching);
if (c.Name != null) {
VariableInfo vi = c.Block.GetVariableInfo (c.Name);
if (vi == null)
throw new Exception ();
vi.Number = -1;
}
bool old_in_catch = ec.InCatch;
ec.InCatch = true;
if (!c.Resolve (ec))
ok = false;
ec.InCatch = old_in_catch;
FlowBranching.UsageVector current = ec.CurrentBranching.CurrentUsageVector;
if (!current.AlwaysReturns && !current.AlwaysBreaks)
vector.AndLocals (current);
}
Report.Debug (1, "END OF CATCH BLOCKS", ec.CurrentBranching);
if (General != null){
ec.CurrentBranching.CreateSibling ();
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;
FlowBranching.UsageVector current = ec.CurrentBranching.CurrentUsageVector;
if (!current.AlwaysReturns && !current.AlwaysBreaks)
vector.AndLocals (current);
}
Report.Debug (1, "END OF GENERAL CATCH BLOCKS", ec.CurrentBranching);
if (Fini != null) {
ec.CurrentBranching.CreateSiblingForFinally ();
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.UsageVector f_vector = ec.CurrentBranching.CurrentUsageVector;
FlowReturns returns = ec.EndFlowBranching ();
Report.Debug (1, "END OF FINALLY", ec.CurrentBranching, returns, vector, f_vector);
if ((returns == FlowReturns.SOMETIMES) || (returns == FlowReturns.ALWAYS)) {
ec.CurrentBranching.CheckOutParameters (f_vector.Parameters, loc);
}
ec.CurrentBranching.CurrentUsageVector.Or (vector);
Report.Debug (1, "END OF TRY", ec.CurrentBranching);
return ok;
}
public override bool Emit (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){
VariableInfo vi;
ig.BeginCatchBlock (c.CatchType);
if (c.Name != null){
vi = c.Block.GetVariableInfo (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--;
if (!returns || ec.InTry || ec.InCatch)
return returns;
// 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.
if (ec.ReturnType != null)
ec.ig.Emit (OpCodes.Ldloc, ec.TemporaryReturn ());
ec.ig.Emit (OpCodes.Ret);
return true;
}
}
//
// FIXME: We still do not support the expression variant of the using
// statement.
//
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] = Expression.ConvertImplicit (
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 = Expression.ConvertImplicit (
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;
}
return Statement.Resolve (ec);
}
public override bool Emit (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;
LocalVariableReference 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 = array_type.GetElementType ();
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);
}
//
// 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;
if (variable.ResolveLValue (ec, empty) == null)
return false;
if (!statement.Resolve (ec))
return false;
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;
}
//
// 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))) {
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 = 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;
LocalBuilder enumerator, disposable;
enumerator = ig.DeclareLocal (hm.enumerator_type);
if (hm.is_disposable)
disposable = ig.DeclareLocal (TypeManager.idisposable_type);
else
disposable = null;
//
// 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;
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);
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
//
if (hm.is_disposable) {
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)
{
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)
{
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;
}
}
}