// <summary>
// The type of a FlowBranching.
// </summary>
- public enum BranchingType {
+ public enum BranchingType : byte {
// Normal (conditional or toplevel) block.
Block,
Conditional,
// A loop block.
- LoopBlock,
+ Loop,
// Try/Catch block.
Exception,
// <summary>
// The type of one sibling of a branching.
// </summary>
- public enum SiblingType {
+ public enum SiblingType : byte {
Block,
Conditional,
SwitchSection,
// current code block may return to its enclosing block before reaching
// its end.
// </summary>
- public enum FlowReturns {
+ public enum FlowReturns : byte {
Undefined = 0,
// It can never return.
public sealed class Reachability
{
- FlowReturns returns, breaks, throws, barrier, reachable;
+ FlowReturns returns, breaks, throws, barrier;
public FlowReturns Returns {
get { return returns; }
public FlowReturns Barrier {
get { return barrier; }
}
- public FlowReturns Reachable {
- get { return reachable; }
- }
-
public Reachability (FlowReturns returns, FlowReturns breaks,
FlowReturns throws, FlowReturns barrier)
{
this.breaks = breaks;
this.throws = throws;
this.barrier = barrier;
-
- update ();
}
public Reachability Clone ()
{
- Reachability cloned = new Reachability (returns, breaks, throws, barrier);
- cloned.reachable = reachable;
- return cloned;
+ return new Reachability (returns, breaks, throws, barrier);
+ }
+
+ // <summary>
+ // Performs an `And' operation on the FlowReturns status
+ // (for instance, a block only returns Always if all its siblings
+ // always return).
+ // </summary>
+ public static FlowReturns AndFlowReturns (FlowReturns a, FlowReturns b)
+ {
+ if (a == FlowReturns.Undefined)
+ return b;
+
+ 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)
+ return FlowReturns.Always;
+ else
+ return FlowReturns.Sometimes;
+
+ default:
+ throw new ArgumentException ();
+ }
+ }
+
+ public static FlowReturns OrFlowReturns (FlowReturns a, FlowReturns b)
+ {
+ if (a == FlowReturns.Undefined)
+ return b;
+
+ switch (a) {
+ case FlowReturns.Never:
+ return b;
+
+ case FlowReturns.Sometimes:
+ if (b == FlowReturns.Always)
+ return FlowReturns.Always;
+ else
+ return FlowReturns.Sometimes;
+
+ case FlowReturns.Always:
+ return FlowReturns.Always;
+
+ default:
+ throw new ArgumentException ();
+ }
}
public static void And (ref Reachability a, Reachability b, bool do_break)
return;
}
- Report.Debug (4, "AND REACHABILITY", a, b, do_break);
+ a.And (b, do_break);
+ }
+ public void And (Reachability b, bool do_break)
+ {
//
// `break' does not "break" in a Switch or a LoopBlock
//
- bool a_breaks = do_break && a.AlwaysBreaks;
+ bool a_breaks = do_break && AlwaysBreaks;
bool b_breaks = do_break && b.AlwaysBreaks;
bool a_has_barrier, b_has_barrier;
// This is the normal case: the code following a barrier
// cannot be reached.
//
- a_has_barrier = a.AlwaysHasBarrier;
+ a_has_barrier = AlwaysHasBarrier;
b_has_barrier = b.AlwaysHasBarrier;
} else {
//
// Special case for Switch and LoopBlocks: we can reach the
// code after the barrier via the `break'.
//
- a_has_barrier = !a.AlwaysBreaks && a.AlwaysHasBarrier;
+ a_has_barrier = !AlwaysBreaks && AlwaysHasBarrier;
b_has_barrier = !b.AlwaysBreaks && b.AlwaysHasBarrier;
}
- bool a_unreachable = a_breaks || a.AlwaysThrows || a_has_barrier;
+ bool a_unreachable = a_breaks || AlwaysThrows || a_has_barrier;
bool b_unreachable = b_breaks || b.AlwaysThrows || b_has_barrier;
//
// Do all code paths always return ?
//
- if (a.AlwaysReturns) {
+ if (AlwaysReturns) {
if (b.AlwaysReturns || b_unreachable)
- a.returns = FlowReturns.Always;
+ returns = FlowReturns.Always;
else
- a.returns = FlowReturns.Sometimes;
+ returns = FlowReturns.Sometimes;
} else if (b.AlwaysReturns) {
- if (a.AlwaysReturns || a_unreachable)
- a.returns = FlowReturns.Always;
+ if (AlwaysReturns || a_unreachable)
+ returns = FlowReturns.Always;
else
- a.returns = FlowReturns.Sometimes;
- } else if (!a.MayReturn) {
+ returns = FlowReturns.Sometimes;
+ } else if (!MayReturn) {
if (b.MayReturn)
- a.returns = FlowReturns.Sometimes;
+ returns = FlowReturns.Sometimes;
else
- a.returns = FlowReturns.Never;
+ returns = FlowReturns.Never;
} else if (!b.MayReturn) {
- if (a.MayReturn)
- a.returns = FlowReturns.Sometimes;
+ if (MayReturn)
+ returns = FlowReturns.Sometimes;
else
- a.returns = FlowReturns.Never;
+ returns = FlowReturns.Never;
}
- a.breaks = AndFlowReturns (a.breaks, b.breaks);
- a.throws = AndFlowReturns (a.throws, b.throws);
- a.barrier = AndFlowReturns (a.barrier, b.barrier);
+ breaks = AndFlowReturns (breaks, b.breaks);
+ throws = AndFlowReturns (throws, b.throws);
+ barrier = AndFlowReturns (barrier, b.barrier);
+
+ if (a_unreachable && b_unreachable)
+ barrier = FlowReturns.Always;
+ else if (a_unreachable || b_unreachable)
+ barrier = FlowReturns.Sometimes;
+ else
+ barrier = FlowReturns.Never;
+ }
- a.reachable = AndFlowReturns (a.reachable, b.reachable);
+ public void Or (Reachability b)
+ {
+ returns = OrFlowReturns (returns, b.returns);
+ breaks = OrFlowReturns (breaks, b.breaks);
+ throws = OrFlowReturns (throws, b.throws);
+ barrier = OrFlowReturns (barrier, b.barrier);
}
public static Reachability Never ()
FlowReturns.Never, FlowReturns.Never);
}
- void update ()
- {
- if ((returns == FlowReturns.Always) || (breaks == FlowReturns.Always) ||
- (throws == FlowReturns.Always) || (barrier == FlowReturns.Always))
- reachable = FlowReturns.Never;
- else if ((returns == FlowReturns.Never) && (breaks == FlowReturns.Never) &&
- (throws == FlowReturns.Never) && (barrier == FlowReturns.Never))
- reachable = FlowReturns.Always;
- else
- reachable = FlowReturns.Sometimes;
+ public FlowReturns Reachable {
+ get {
+ if ((returns == FlowReturns.Always) ||
+ (breaks == FlowReturns.Always) ||
+ (throws == FlowReturns.Always) ||
+ (barrier == FlowReturns.Always))
+ return FlowReturns.Never;
+ else if ((returns == FlowReturns.Never) &&
+ (breaks == FlowReturns.Never) &&
+ (throws == FlowReturns.Never) &&
+ (barrier == FlowReturns.Never))
+ return FlowReturns.Always;
+ else
+ return FlowReturns.Sometimes;
+ }
}
public bool AlwaysBreaks {
}
public bool IsUnreachable {
- get { return reachable == FlowReturns.Never; }
+ get { return Reachable == FlowReturns.Never; }
}
public void SetReturns ()
{
returns = FlowReturns.Always;
- update ();
}
public void SetReturnsSometimes ()
{
returns = FlowReturns.Sometimes;
- update ();
}
public void SetBreaks ()
{
breaks = FlowReturns.Always;
- update ();
}
public void ResetBreaks ()
{
breaks = FlowReturns.Never;
- update ();
}
public void SetThrows ()
{
throws = FlowReturns.Always;
- update ();
+ }
+
+ public void SetThrowsSometimes ()
+ {
+ throws = FlowReturns.Sometimes;
}
public void SetBarrier ()
{
barrier = FlowReturns.Always;
- update ();
+ }
+
+ public void ResetBarrier ()
+ {
+ barrier = FlowReturns.Never;
}
static string ShortName (FlowReturns returns)
return String.Format ("[{0}:{1}:{2}:{3}:{4}]",
ShortName (returns), ShortName (breaks),
ShortName (throws), ShortName (barrier),
- ShortName (reachable));
+ ShortName (Reachable));
}
}
{
switch (type) {
case BranchingType.Exception:
- return new FlowBranchingException (parent, type, block, loc);
+ throw new InvalidOperationException ();
case BranchingType.Switch:
- return new FlowBranchingBlock (parent, type, SiblingType.SwitchSection, block, loc);
+ return new FlowBranchingSwitch (parent, block, loc);
case BranchingType.SwitchSection:
return new FlowBranchingBlock (parent, type, SiblingType.Block, block, loc);
case BranchingType.Block:
return new FlowBranchingBlock (parent, type, SiblingType.Block, block, loc);
+ case BranchingType.Loop:
+ return new FlowBranchingLoop (parent, block, loc);
+
default:
return new FlowBranchingBlock (parent, type, SiblingType.Conditional, block, loc);
}
static int next_id = 0;
int id;
- // <summary>
- // Performs an `And' operation on the FlowReturns status
- // (for instance, a block only returns Always if all its siblings
- // always return).
- // </summary>
- public static FlowReturns AndFlowReturns (FlowReturns a, FlowReturns b)
- {
- if (a == FlowReturns.Undefined)
- return b;
-
- 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)
- return FlowReturns.Always;
- else
- return FlowReturns.Sometimes;
-
- default:
- throw new ArgumentException ();
- }
-
- return b;
- }
-
// <summary>
// The vector contains a BitArray with information about which local variables
// and parameters are already initialized at the current code position.
// </summary>
public readonly Location Location;
+ // <summary>
+ // This is only valid for SwitchSection, Try, Catch and Finally.
+ // </summary>
+ public readonly Block Block;
+
// <summary>
// If this is true, then the usage vector has been modified and must be
// merged when we're done with this branching.
// </summary>
public readonly UsageVector InheritsFrom;
+ // <summary>
+ // This is used to construct a list of UsageVector's.
+ // </summary>
+ public UsageVector Next;
+
//
// Private.
//
MyBitVector locals, parameters;
Reachability reachability;
- bool is_finally;
static int next_id = 0;
int id;
//
// Normally, you should not use any of these constructors.
//
- public UsageVector (SiblingType type, UsageVector parent, Location loc, int num_params, int num_locals)
+ public UsageVector (SiblingType type, UsageVector parent,
+ Block block, Location loc,
+ int num_params, int num_locals)
{
this.Type = type;
+ this.Block = block;
this.Location = loc;
this.InheritsFrom = parent;
this.CountParameters = num_params;
this.CountLocals = num_locals;
if (parent != null) {
- locals = new MyBitVector (parent.locals, CountLocals);
+ if (num_locals > 0)
+ locals = new MyBitVector (parent.locals, CountLocals);
+
if (num_params > 0)
parameters = new MyBitVector (parent.parameters, num_params);
reachability = parent.Reachability.Clone ();
} else {
- locals = new MyBitVector (null, CountLocals);
+ if (num_locals > 0)
+ locals = new MyBitVector (null, CountLocals);
+
if (num_params > 0)
parameters = new MyBitVector (null, num_params);
id = ++next_id;
}
- public UsageVector (SiblingType type, UsageVector parent, Location loc)
- : this (type, parent, loc, parent.CountParameters, parent.CountLocals)
+ public UsageVector (SiblingType type, UsageVector parent,
+ Block block, Location loc)
+ : this (type, parent, block, loc,
+ parent.CountParameters, parent.CountLocals)
{ }
public UsageVector (MyBitVector parameters, MyBitVector locals,
- Reachability reachability, Location loc)
+ Reachability reachability, Block block,
+ Location loc)
{
this.Type = SiblingType.Block;
this.Location = loc;
+ this.Block = block;
this.reachability = reachability;
this.parameters = parameters;
// </summary>
public UsageVector Clone ()
{
- UsageVector retval = new UsageVector (Type, null, Location, CountParameters, CountLocals);
+ UsageVector retval = new UsageVector (
+ Type, null, Block, Location,
+ CountParameters, CountLocals);
- retval.locals = locals.Clone ();
+ if (retval.locals != null)
+ retval.locals = locals.Clone ();
+
if (parameters != null)
retval.parameters = parameters.Clone ();
+
retval.reachability = reachability.Clone ();
return retval;
public bool IsAssigned (VariableInfo var)
{
- if (!var.IsParameter && Reachability.AlwaysBreaks)
+ if (!var.IsParameter && Reachability.IsUnreachable)
return true;
return var.IsAssigned (var.IsParameter ? parameters : locals);
public void SetAssigned (VariableInfo var)
{
- if (!var.IsParameter && Reachability.AlwaysBreaks)
+ if (!var.IsParameter && Reachability.IsUnreachable)
return;
IsDirty = true;
public bool IsFieldAssigned (VariableInfo var, string name)
{
- if (!var.IsParameter && Reachability.AlwaysBreaks)
+ if (!var.IsParameter && Reachability.IsUnreachable)
return true;
return var.IsFieldAssigned (var.IsParameter ? parameters : locals, name);
public void SetFieldAssigned (VariableInfo var, string name)
{
- if (!var.IsParameter && Reachability.AlwaysBreaks)
+ if (!var.IsParameter && Reachability.IsUnreachable)
return;
IsDirty = true;
// <summary>
// Merges a child branching.
// </summary>
- public void MergeResult (MyBitVector new_params, MyBitVector new_locals,
- Reachability new_reachability)
+ public UsageVector MergeChild (FlowBranching branching)
{
- Report.Debug (2, " MERGING RESULT", this, IsDirty,
- new_params, new_locals, new_reachability, Type);
+ UsageVector result = branching.Merge ();
+
+ Report.Debug (2, " MERGING CHILD", this, branching, IsDirty,
+ result.ParameterVector, result.LocalVector,
+ result.Reachability, reachability, Type);
+
+ Reachability new_r = result.Reachability;
+
+ if (branching.Type == BranchingType.Loop) {
+ bool may_leave_loop = new_r.MayBreak;
+ new_r.ResetBreaks ();
+
+ if (branching.Infinite && !may_leave_loop) {
+ if (new_r.Returns == FlowReturns.Sometimes) {
+ // If we're an infinite loop and do not break,
+ // the code after the loop can never be reached.
+ // However, if we may return from the loop,
+ // then we do always return (or stay in the
+ // loop forever).
+ new_r.SetReturns ();
+ }
- reachability = new_reachability;
+ new_r.SetBarrier ();
+ }
+
+ if (may_leave_loop)
+ new_r.ResetBarrier ();
+ } else if (branching.Type == BranchingType.Switch) {
+ if (new_r.MayBreak || new_r.MayReturn)
+ new_r.ResetBarrier ();
+
+ new_r.ResetBreaks ();
+ }
//
// We've now either reached the point after the branching or we will
// we need to look at (see above).
//
- if ((Type == SiblingType.SwitchSection) && !reachability.IsUnreachable) {
+ if ((Type == SiblingType.SwitchSection) && !new_r.IsUnreachable) {
Report.Error (163, Location,
"Control cannot fall through from one " +
"case label to another");
- return;
+ return result;
}
- if (new_locals != null)
- locals.Or (new_locals);
+ if (locals != null && result.LocalVector != null)
+ locals.Or (result.LocalVector);
+
+ if (result.ParameterVector != null)
+ parameters.Or (result.ParameterVector);
- if (new_params != null)
- parameters.Or (new_params);
+ if ((branching.Type == BranchingType.Block) && branching.Block.Implicit)
+ reachability = new_r.Clone ();
+ else
+ reachability.Or (new_r);
- Report.Debug (2, " MERGING RESULT DONE", this);
+ Report.Debug (2, " MERGING CHILD DONE", this, result,
+ new_r, reachability);
IsDirty = true;
+
+ return result;
}
- protected void MergeFinally (FlowBranching branching, ArrayList finally_vectors,
+ protected void MergeFinally (FlowBranching branching, UsageVector f_origins,
MyBitVector f_params)
{
- foreach (UsageVector vector in finally_vectors) {
+ for (UsageVector vector = f_origins; vector != null; vector = vector.Next) {
MyBitVector temp_params = f_params.Clone ();
temp_params.Or (vector.Parameters);
-
- branching.CheckOutParameters (temp_params, branching.Location);
}
}
public void MergeFinally (FlowBranching branching, UsageVector f_vector,
- ArrayList vectors)
+ UsageVector f_origins)
{
if (parameters != null) {
if (f_vector != null) {
- MergeFinally (branching, vectors, f_vector.Parameters);
+ MergeFinally (branching, f_origins, f_vector.Parameters);
MyBitVector.Or (ref parameters, f_vector.ParameterVector);
} else
- MergeFinally (branching, vectors, parameters);
+ MergeFinally (branching, f_origins, parameters);
}
- if (f_vector != null)
+ if (f_vector != null && f_vector.LocalVector != null)
MyBitVector.Or (ref locals, f_vector.LocalVector);
}
// 8 Console.WriteLine (a);
//
// </summary>
- public void MergeJumpOrigins (ICollection origin_vectors)
+ public void MergeJumpOrigins (UsageVector o_vectors)
{
- Report.Debug (1, " MERGING JUMP ORIGIN", this);
+ Report.Debug (1, " MERGING JUMP ORIGINS", this);
reachability = Reachability.Never ();
- if (origin_vectors == null)
+ if (o_vectors == null) {
+ reachability.SetBarrier ();
return;
+ }
- foreach (UsageVector vector in origin_vectors) {
- Report.Debug (1, " MERGING JUMP ORIGIN", vector);
-
- locals.And (vector.locals);
- if (parameters != null)
- parameters.And (vector.parameters);
-
+ bool first = true;
+
+ for (UsageVector vector = o_vectors; vector != null;
+ vector = vector.Next) {
+ Report.Debug (1, " MERGING JUMP ORIGIN", vector,
+ first, locals, vector.Locals);
+
+ if (first) {
+ if (locals != null && vector.Locals != null)
+ locals.Or (vector.locals);
+
+ if (parameters != null)
+ parameters.Or (vector.parameters);
+ first = false;
+ } else {
+ if (locals != null)
+ locals.And (vector.locals);
+ if (parameters != null)
+ parameters.And (vector.parameters);
+ }
+
Reachability.And (ref reachability, vector.Reachability, true);
+
+ Report.Debug (1, " MERGING JUMP ORIGIN #1", vector);
}
- Report.Debug (1, " MERGING JUMP ORIGIN DONE", this);
+ Report.Debug (1, " MERGING JUMP ORIGINS DONE", this);
}
// <summary>
// 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.
// </summary>
- public void MergeFinallyOrigins (ICollection finally_vectors)
+ public void MergeFinallyOrigins (UsageVector f_origins)
{
Report.Debug (1, " MERGING FINALLY ORIGIN", this);
-#if FIXME
- RealBreaks = FlowReturns.Never;
-#endif
+ reachability = Reachability.Never ();
- foreach (UsageVector vector in finally_vectors) {
+ for (UsageVector vector = f_origins; vector != null; vector = vector.Next) {
Report.Debug (1, " MERGING FINALLY ORIGIN", vector);
if (parameters != null)
parameters.And (vector.parameters);
-#if FIXME
- RealBreaks = AndFlowReturns (Breaks, vector.Breaks);
-#endif
+ Reachability.And (ref reachability, vector.Reachability, true);
}
- is_finally = true;
-
Report.Debug (1, " MERGING FINALLY ORIGIN DONE", this);
}
+ public void MergeBreakOrigins (FlowBranching branching, UsageVector o_vectors)
+ {
+ Report.Debug (1, " MERGING BREAK ORIGINS", this);
+
+ if (o_vectors == null)
+ return;
+
+ bool first = branching.Infinite;
+
+ for (UsageVector vector = o_vectors; vector != null;
+ vector = vector.Next) {
+ Report.Debug (1, " MERGING BREAK ORIGIN", vector, first);
+
+ if (first) {
+ if (locals != null && vector.Locals != null)
+ locals.Or (vector.locals);
+
+ if (parameters != null)
+ parameters.Or (vector.parameters);
+ first = false;
+ } else {
+ if (locals != null && vector.Locals != null)
+ locals.And (vector.locals);
+ if (parameters != null)
+ parameters.And (vector.parameters);
+ }
+
+ reachability.And (vector.Reachability, false);
+ }
+
+ Report.Debug (1, " MERGING BREAK ORIGINS DONE", this);
+ }
+
public void CheckOutParameters (FlowBranching branching)
{
if (parameters != null)
// </summary>
public MyBitVector Locals {
get {
- return locals.Clone ();
+ if (locals != null)
+ return locals.Clone ();
+ else
+ return null;
}
}
StringBuilder sb = new StringBuilder ();
sb.Append ("Vector (");
+ sb.Append (Type);
+ sb.Append (",");
sb.Append (id);
sb.Append (",");
sb.Append (IsDirty);
local_map = Block.LocalMap;
UsageVector parent_vector = parent != null ? parent.CurrentUsageVector : null;
- vector = new UsageVector (stype, parent_vector, loc, param_map.Length, local_map.Length);
+ vector = new UsageVector (
+ stype, parent_vector, Block, loc,
+ param_map.Length, local_map.Length);
} else {
param_map = Parent.param_map;
local_map = Parent.local_map;
- vector = new UsageVector (stype, Parent.CurrentUsageVector, loc);
+ vector = new UsageVector (
+ stype, Parent.CurrentUsageVector, null, loc);
}
AddSibling (vector);
// <summary>
// Creates a sibling of the current usage vector.
// </summary>
- public virtual void CreateSibling (SiblingType type)
+ public virtual void CreateSibling (Block block, SiblingType type)
{
- AddSibling (new UsageVector (type, Parent.CurrentUsageVector, Location));
+ UsageVector vector = new UsageVector (
+ type, Parent.CurrentUsageVector, block, Location);
+ AddSibling (vector);
Report.Debug (1, " CREATED SIBLING", CurrentUsageVector);
}
+ public void CreateSibling ()
+ {
+ CreateSibling (null, SiblingType.Conditional);
+ }
+
protected abstract void AddSibling (UsageVector uv);
- public abstract void Label (ArrayList origin_vectors);
+ public virtual LabeledStatement LookupLabel (string name, Location loc)
+ {
+ if (Parent != null)
+ return Parent.LookupLabel (name, loc);
+
+ Report.Error (
+ 159, loc,
+ "No such label `" + name + "' in this scope");
+ return null;
+ }
+
+ public abstract void Label (UsageVector origin_vectors);
// <summary>
// Check whether all `out' parameters have been assigned.
continue;
Report.Error (177, loc, "The out parameter `" +
- param_map.VariableNames [i] + "' must be " +
- "assigned before control leave the current method.");
+ var.Name + "' must be " +
+ "assigned before control leaves the current method.");
}
}
- protected UsageVector Merge (ArrayList children)
+ protected UsageVector Merge (UsageVector sibling_list)
{
+ if (sibling_list.Next == null)
+ return sibling_list;
+
MyBitVector locals = null;
MyBitVector parameters = null;
Reachability reachability = null;
- Report.Debug (2, " MERGING CHILDREN", Name, children.Count);
-
- int children_count = children.Count;
- for (int ix = 0; ix < children_count; ix++){
- UsageVector child = (UsageVector) children [ix];
+ Report.Debug (2, " MERGING SIBLINGS", this, Name);
+ for (UsageVector child = sibling_list; child != null; child = child.Next) {
bool do_break = (Type != BranchingType.Switch) &&
- (Type != BranchingType.LoopBlock);
+ (Type != BranchingType.Loop);
- Report.Debug (2, " MERGING CHILD ", child,
- child.Locals, child.Parameters,
+ Report.Debug (2, " MERGING SIBLING ", child,
+ child.ParameterVector, child.LocalVector,
reachability, child.Reachability, do_break);
Reachability.And (ref reachability, child.Reachability, do_break);
//
bool do_break_2 = (child.Type != SiblingType.Block) &&
(child.Type != SiblingType.SwitchSection);
- bool unreachable = (do_break_2 && child.Reachability.AlwaysBreaks) ||
- child.Reachability.AlwaysThrows ||
+ bool always_throws = (child.Type != SiblingType.Try) &&
+ child.Reachability.AlwaysThrows;
+ bool unreachable = always_throws ||
+ (do_break_2 && child.Reachability.AlwaysBreaks) ||
child.Reachability.AlwaysReturns ||
child.Reachability.AlwaysHasBarrier;
- Report.Debug (2, " MERGING CHILD #1", reachability,
+ Report.Debug (2, " MERGING SIBLING #1", reachability,
Type, child.Type, child.Reachability.IsUnreachable,
- do_break_2, unreachable);
+ do_break_2, always_throws, unreachable);
- if (!unreachable)
+ if (!unreachable && (child.LocalVector != null))
MyBitVector.And (ref locals, child.LocalVector);
// An `out' parameter must be assigned in all branches which do
// not always throw an exception.
- if ((child.Type != SiblingType.Catch) &&
- (child.ParameterVector != null) && !child.Reachability.AlwaysThrows)
+ if ((child.ParameterVector != null) && !child.Reachability.AlwaysThrows)
MyBitVector.And (ref parameters, child.ParameterVector);
+
+ Report.Debug (2, " MERGING SIBLING #2", parameters, locals);
}
if (reachability == null)
reachability = Reachability.Never ();
- Report.Debug (2, " MERGING CHILDREN #1 ", Type, reachability,
- Infinite, reachability.MayBreak);
-
- if (Type == BranchingType.LoopBlock) {
- bool may_leave_loop = reachability.MayBreak;
- reachability.ResetBreaks ();
-
- if (Infinite && !may_leave_loop) {
- if (reachability.Returns == FlowReturns.Sometimes) {
- // If we're an infinite loop and do not break, the code
- // after the loop can never be reached. However, if we
- // may return from the loop, then we do always return
- // (or stay in the loop forever).
- reachability.SetReturns ();
- }
-
- reachability.SetBarrier ();
- } else {
- if (reachability.Returns == FlowReturns.Always) {
- // We're either finite or we may leave the loop.
- reachability.SetReturnsSometimes ();
- }
- }
- } else if (Type == BranchingType.Switch)
- reachability.ResetBreaks ();
-
- Report.Debug (2, " MERGING CHILDREN DONE", parameters, locals,
+ Report.Debug (2, " MERGING SIBLINGS DONE", parameters, locals,
reachability, Infinite);
- return new UsageVector (parameters, locals, reachability, Location);
+ return new UsageVector (
+ parameters, locals, reachability, null, Location);
}
protected abstract UsageVector Merge ();
// <summary>
// Merge a child branching.
// </summary>
- public Reachability MergeChild (FlowBranching child)
+ public UsageVector MergeChild (FlowBranching child)
{
- UsageVector result = child.Merge ();
-
- CurrentUsageVector.MergeResult (
- result.ParameterVector, result.LocalVector, result.Reachability);
-
- Report.Debug (4, " MERGE CHILD", Location, child, CurrentUsageVector,
- result.Reachability);
-
- return result.Reachability;
+ return CurrentUsageVector.MergeChild (child);
}
// <summary>
throw new NotSupportedException ();
UsageVector vector = new UsageVector (
- SiblingType.Conditional, null, Location, param_map.Length, local_map.Length);
+ SiblingType.Block, null, Block, Location,
+ param_map.Length, local_map.Length);
- UsageVector result = Merge ();
- vector.MergeResult (result.ParameterVector, result.LocalVector,
- result.Reachability);
+ UsageVector result = vector.MergeChild (this);
Report.Debug (4, "MERGE TOP BLOCK", Location, vector, result.Reachability);
- if (vector.Reachability.Throws != FlowReturns.Always)
+ if ((vector.Reachability.Throws != FlowReturns.Always) &&
+ (vector.Reachability.Barrier != FlowReturns.Always))
CheckOutParameters (vector.Parameters, Location);
return result.Reachability;
}
- public virtual bool InTryBlock ()
+ //
+ // Checks whether we're in a `try' block.
+ //
+ public virtual bool InTryOrCatch (bool is_return)
+ {
+ if ((Block != null) && Block.IsDestructor)
+ return true;
+ else if (!is_return &&
+ ((Type == BranchingType.Loop) || (Type == BranchingType.Switch)))
+ return false;
+ else if (Parent != null)
+ return Parent.InTryOrCatch (is_return);
+ else
+ return false;
+ }
+
+ public virtual bool InTryWithCatch ()
{
if (Parent != null)
- return Parent.InTryBlock ();
+ return Parent.InTryWithCatch ();
+ return false;
+ }
+
+ public virtual bool InLoop ()
+ {
+ if (Type == BranchingType.Loop)
+ return true;
+ else if (Parent != null)
+ return Parent.InLoop ();
+ else
+ return false;
+ }
+
+ public virtual bool InSwitch ()
+ {
+ if (Type == BranchingType.Switch)
+ return true;
+ else if (Parent != null)
+ return Parent.InSwitch ();
+ else
+ return false;
+ }
+
+ public virtual bool BreakCrossesTryCatchBoundary ()
+ {
+ if ((Type == BranchingType.Loop) || (Type == BranchingType.Switch))
+ return false;
+ else if (Parent != null)
+ return Parent.BreakCrossesTryCatchBoundary ();
else
return false;
}
{
if (Parent != null)
Parent.AddFinallyVector (vector);
- else
+ else if ((Block == null) || !Block.IsDestructor)
+ throw new NotSupportedException ();
+ }
+
+ public virtual void AddBreakVector (UsageVector vector)
+ {
+ if (Parent != null)
+ Parent.AddBreakVector (vector);
+ else if ((Block == null) || !Block.IsDestructor)
throw new NotSupportedException ();
}
+ public virtual void StealFinallyClauses (ref ArrayList list)
+ {
+ if (Parent != null)
+ Parent.StealFinallyClauses (ref list);
+ }
+
public bool IsAssigned (VariableInfo vi)
{
return CurrentUsageVector.IsAssigned (vi);
public class FlowBranchingBlock : FlowBranching
{
- UsageVector current_vector;
- ArrayList siblings = new ArrayList ();
+ UsageVector sibling_list = null;
- public FlowBranchingBlock (FlowBranching parent, BranchingType type, SiblingType stype,
- Block block, Location loc)
+ public FlowBranchingBlock (FlowBranching parent, BranchingType type,
+ SiblingType stype, Block block, Location loc)
: base (parent, type, stype, block, loc)
{ }
public override UsageVector CurrentUsageVector {
- get { return current_vector; }
+ get { return sibling_list; }
}
protected override void AddSibling (UsageVector sibling)
{
- siblings.Add (sibling);
- current_vector = sibling;
+ sibling.Next = sibling_list;
+ sibling_list = sibling;
+ }
+
+ public override LabeledStatement LookupLabel (string name, Location loc)
+ {
+ if (Block == null)
+ return base.LookupLabel (name, loc);
+
+ LabeledStatement s = Block.LookupLabel (name);
+ if (s != null)
+ return s;
+
+ return base.LookupLabel (name, loc);
}
- public override void Label (ArrayList origin_vectors)
+ public override void Label (UsageVector origin_vectors)
{
+ if (!CurrentUsageVector.Reachability.IsUnreachable) {
+ UsageVector vector = CurrentUsageVector.Clone ();
+ vector.Next = origin_vectors;
+ origin_vectors = vector;
+ }
+
CurrentUsageVector.MergeJumpOrigins (origin_vectors);
}
protected override UsageVector Merge ()
{
- return Merge (siblings);
+ return Merge (sibling_list);
}
}
- public class FlowBranchingException : FlowBranching
+ public class FlowBranchingLoop : FlowBranchingBlock
+ {
+ UsageVector break_origins;
+
+ public FlowBranchingLoop (FlowBranching parent, Block block, Location loc)
+ : base (parent, BranchingType.Loop, SiblingType.Conditional, block, loc)
+ { }
+
+ public override void AddBreakVector (UsageVector vector)
+ {
+ vector = vector.Clone ();
+ vector.Next = break_origins;
+ break_origins = vector;
+ }
+
+ protected override UsageVector Merge ()
+ {
+ UsageVector vector = base.Merge ();
+
+ vector.MergeBreakOrigins (this, break_origins);
+
+ return vector;
+ }
+ }
+
+ public class FlowBranchingSwitch : FlowBranchingBlock
{
- ArrayList finally_vectors;
+ UsageVector break_origins;
+
+ public FlowBranchingSwitch (FlowBranching parent, Block block, Location loc)
+ : base (parent, BranchingType.Switch, SiblingType.SwitchSection, block, loc)
+ { }
+
+ public override void AddBreakVector (UsageVector vector)
+ {
+ vector = vector.Clone ();
+ vector.Next = break_origins;
+ break_origins = vector;
+ }
+
+ protected override UsageVector Merge ()
+ {
+ UsageVector vector = base.Merge ();
+
+ vector.MergeBreakOrigins (this, break_origins);
+
+ return vector;
+ }
+ }
- bool has_params;
+ public class FlowBranchingException : FlowBranching
+ {
+ ExceptionStatement stmt;
UsageVector current_vector;
- UsageVector try_vector;
- ArrayList catch_vectors = new ArrayList ();
+ UsageVector catch_vectors;
UsageVector finally_vector;
+ UsageVector finally_origins;
+ bool emit_finally;
- public FlowBranchingException (FlowBranching parent, BranchingType type, Block block, Location loc)
- : base (parent, type, SiblingType.Try, block, loc)
+ public FlowBranchingException (FlowBranching parent,
+ ExceptionStatement stmt)
+ : base (parent, BranchingType.Exception, SiblingType.Try,
+ null, stmt.loc)
{
- finally_vectors = new ArrayList ();
- has_params = current_vector.HasParameters;
+ this.stmt = stmt;
+ this.emit_finally = true;
}
protected override void AddSibling (UsageVector sibling)
{
if (sibling.Type == SiblingType.Try) {
- try_vector = sibling;
- catch_vectors.Add (sibling);
- } else if (sibling.Type == SiblingType.Catch)
- catch_vectors.Add (sibling);
- else if (sibling.Type == SiblingType.Finally) {
- // sibling.MergeFinallyOrigins (finally_vectors);
+ sibling.Next = catch_vectors;
+ catch_vectors = sibling;
+ } else if (sibling.Type == SiblingType.Catch) {
+ sibling.Next = catch_vectors;
+ catch_vectors = sibling;
+ } else if (sibling.Type == SiblingType.Finally) {
+ sibling.MergeFinallyOrigins (finally_origins);
finally_vector = sibling;
} else
throw new InvalidOperationException ();
get { return current_vector; }
}
- public override bool InTryBlock ()
+ public override bool InTryOrCatch (bool is_return)
+ {
+ return finally_vector == null;
+ }
+
+ public override bool InTryWithCatch ()
+ {
+ if (finally_vector == null) {
+ Try t = stmt as Try;
+ if (t != null && t.HasCatch)
+ return true;
+ }
+
+ if (Parent != null)
+ return Parent.InTryWithCatch ();
+
+ return false;
+ }
+
+ public override bool BreakCrossesTryCatchBoundary ()
{
return true;
}
public override void AddFinallyVector (UsageVector vector)
{
- finally_vectors.Add (vector.Clone ());
+ vector = vector.Clone ();
+ vector.Next = finally_origins;
+ finally_origins = vector;
}
- public override void Label (ArrayList origin_vectors)
+ public override void StealFinallyClauses (ref ArrayList list)
+ {
+ if (list == null)
+ list = new ArrayList ();
+ list.Add (stmt);
+ emit_finally = false;
+ base.StealFinallyClauses (ref list);
+ }
+
+ public bool EmitFinally {
+ get { return emit_finally; }
+ }
+
+ public override LabeledStatement LookupLabel (string name, Location loc)
+ {
+ if (current_vector.Block == null)
+ return base.LookupLabel (name, loc);
+
+ LabeledStatement s = current_vector.Block.LookupLabel (name);
+ if (s != null)
+ return s;
+
+ if (finally_vector != null) {
+ Report.Error (
+ 157, loc, "Control can not leave the body " +
+ "of the finally block");
+ return null;
+ }
+
+ return base.LookupLabel (name, loc);
+ }
+
+ public override void Label (UsageVector origin_vectors)
{
CurrentUsageVector.MergeJumpOrigins (origin_vectors);
}
{
UsageVector vector = Merge (catch_vectors);
- vector.MergeFinally (this, finally_vector, finally_vectors);
+ vector.MergeFinally (this, finally_vector, finally_origins);
return vector;
}
if (type is TypeBuilder) {
TypeContainer tc = TypeManager.LookupTypeContainer (type);
- ArrayList fields = tc.Fields;
+ ArrayList fields = null;
+ if (tc != null)
+ fields = tc.Fields;
ArrayList public_fields = new ArrayList ();
ArrayList non_public_fields = new ArrayList ();
if (fields != null) {
- foreach (Field field in fields) {
+ foreach (FieldMember field in fields) {
if ((field.ModFlags & Modifiers.STATIC) != 0)
continue;
if ((field.ModFlags & Modifiers.PUBLIC) != 0)
// <summary>
public readonly int Length;
- // <summary>
- // Type and name of all the variables.
- // Note that this is null for variables for which we do not need to compute
- // assignment info.
- // </summary>
- public readonly Type[] VariableTypes;
- public readonly string[] VariableNames;
-
VariableInfo[] map;
public VariableMap (InternalParameters ip)
{
Count = ip != null ? ip.Count : 0;
- map = new VariableInfo [Count];
- VariableNames = new string [Count];
- VariableTypes = new Type [Count];
+
+ // Dont bother allocating anything!
+ if (Count == 0)
+ return;
+
Length = 0;
for (int i = 0; i < Count; i++) {
if ((mod & Parameter.Modifier.OUT) == 0)
continue;
-
- VariableNames [i] = ip.ParameterName (i);
- VariableTypes [i] = TypeManager.GetElementType (ip.ParameterType (i));
-
- map [i] = new VariableInfo (VariableNames [i], VariableTypes [i], i, Length);
+
+ // Dont allocate till we find an out var.
+ if (map == null)
+ map = new VariableInfo [Count];
+
+ map [i] = new VariableInfo (ip.ParameterName (i),
+ TypeManager.GetElementType (ip.ParameterType (i)), i, Length);
+
Length += map [i].Length;
}
}
public VariableMap (VariableMap parent, LocalInfo[] locals)
{
int offset = 0, start = 0;
- if (parent != null) {
+ if (parent != null && parent.map != null) {
offset = parent.Length;
start = parent.Count;
}
Count = locals.Length + start;
+
+ if (Count == 0)
+ return;
+
map = new VariableInfo [Count];
- VariableNames = new string [Count];
- VariableTypes = new Type [Count];
Length = offset;
- if (parent != null) {
+ if (parent != null && parent.map != null) {
parent.map.CopyTo (map, 0);
- parent.VariableNames.CopyTo (VariableNames, 0);
- parent.VariableTypes.CopyTo (VariableTypes, 0);
}
for (int i = start; i < Count; i++) {
if (li.VariableType == null)
continue;
- VariableNames [i] = li.Name;
- VariableTypes [i] = li.VariableType;
-
map [i] = li.VariableInfo = new VariableInfo (li, Length);
Length += map [i].Length;
}
// </summary>
public VariableInfo this [int index] {
get {
+ if (map == null)
+ return null;
+
return map [index];
}
}
// </summary>
public void And (MyBitVector new_vector)
{
- BitArray new_array = new_vector.Vector;
+ BitArray new_array;
+
+ if (new_vector != null)
+ new_array = new_vector.Vector;
+ else
+ new_array = new BitArray (Count, false);
initialize_vector ();
{
if (vector != null)
return;
-
+
vector = new BitArray (Count, false);
if (InheritsFrom != null)
Vector = InheritsFrom.Vector;