//
// Author:
// Martin Baulig (martin@ximian.com)
+// Raja R Harinath (rharinath@novell.com)
//
// (C) 2001, 2002, 2003 Ximian, Inc.
//
public sealed class Reachability
{
- TriState returns, throws, barrier;
+ TriState returns, barrier;
public TriState Returns {
get { return returns; }
}
- public TriState Throws {
- get { return throws; }
- }
public TriState Barrier {
get { return barrier; }
}
- Reachability (TriState returns, TriState throws, TriState barrier)
+ Reachability (TriState returns, TriState barrier)
{
this.returns = returns;
- this.throws = throws;
this.barrier = barrier;
}
public Reachability Clone ()
{
- return new Reachability (returns, throws, barrier);
+ return new Reachability (returns, barrier);
}
public static TriState TriState_Meet (TriState a, TriState b)
else
returns = TriState_Meet (returns, b.returns);
- throws = TriState_Meet (throws, b.throws);
barrier = TriState_Meet (barrier, b.barrier);
}
public void Or (Reachability b)
{
returns = TriState_Max (returns, b.returns);
- throws = TriState_Max (throws, b.throws);
barrier = TriState_Max (barrier, b.barrier);
}
public static Reachability Always ()
{
- return new Reachability (TriState.Never, TriState.Never, TriState.Never);
+ return new Reachability (TriState.Never, TriState.Never);
}
TriState Unreachable {
- get { return TriState_Max (returns, TriState_Max (throws, barrier)); }
+ get { return TriState_Max (returns, barrier); }
}
TriState Reachable {
get { return returns == TriState.Always; }
}
- public bool AlwaysThrows {
- get { return throws == TriState.Always; }
- }
-
public bool AlwaysHasBarrier {
get { return barrier == TriState.Always; }
}
returns = TriState.Always;
}
- public void SetThrows ()
- {
- throws = TriState.Always;
- }
-
public void SetBarrier ()
{
barrier = TriState.Always;
public override string ToString ()
{
- return String.Format ("[{0}:{1}:{2}:{3}]",
- ShortName (returns), ShortName (throws), ShortName (barrier),
- ShortName (Reachable));
+ return String.Format ("[{0}:{1}:{2}]",
+ ShortName (returns), ShortName (barrier), ShortName (Reachable));
}
}
reachability.SetReturns ();
}
- public void Throw ()
- {
- if (!reachability.IsUnreachable) {
- reachability.SetThrows ();
- reachability.SetBarrier ();
- }
- }
-
public void Goto ()
{
if (!reachability.IsUnreachable)
MyBitVector locals = null;
MyBitVector parameters = null;
- Reachability reachability = null;
+ Reachability reachability = sibling_list.Reachability.Clone ();
- for (UsageVector child = sibling_list; child != null; child = child.Next) {
- Report.Debug (2, " MERGING SIBLING ", reachability, child);
+ if (!sibling_list.Reachability.IsUnreachable) {
+ locals &= sibling_list.locals;
+ parameters &= sibling_list.parameters;
+ }
- if (reachability == null)
- reachability = child.Reachability.Clone ();
- else
- reachability.Meet (child.Reachability);
-
- // 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.
- //
- bool unreachable = child.Reachability.IsUnreachable;
-
- Report.Debug (2, " MERGING SIBLING #1", reachability,
- child.Type, child.Reachability.IsUnreachable, unreachable);
-
- if (!unreachable)
- MyBitVector.And (ref locals, child.locals);
-
- // An `out' parameter must be assigned in all branches which do
- // not always throw an exception.
- if (!child.Reachability.AlwaysThrows)
- MyBitVector.And (ref parameters, child.parameters);
-
- Report.Debug (2, " MERGING SIBLING #2", parameters, locals);
+ for (UsageVector child = sibling_list.Next; child != null; child = child.Next) {
+ reachability.Meet (child.Reachability);
+
+ if (!child.Reachability.IsUnreachable) {
+ locals &= child.locals;
+ parameters &= child.parameters;
+ }
}
-
- if (reachability == null)
- throw new InternalErrorException ("Cannot happen: the loop above runs at least twice");
return new UsageVector (parameters, locals, reachability, null, loc);
}
return child;
}
- MyBitVector.Or (ref locals, child.locals);
- MyBitVector.Or (ref parameters, child.parameters);
+ locals |= child.locals;
+ parameters |= child.parameters;
if (overwrite)
reachability = new_r.Clone ();
for (UsageVector vector = o_vectors; vector != null; vector = vector.Next) {
Report.Debug (1, " MERGING BREAK ORIGIN", vector);
- MyBitVector.And (ref locals, vector.locals);
- MyBitVector.And (ref parameters, vector.parameters);
+ if (vector.Reachability.IsUnreachable)
+ continue;
+ locals &= vector.locals;
+ parameters &= vector.parameters;
reachability.Meet (vector.Reachability);
}
public class FlowBranchingToplevel : FlowBranchingBlock
{
+ UsageVector return_origins;
+
public FlowBranchingToplevel (FlowBranching parent, ToplevelBlock stmt)
: base (parent, BranchingType.Toplevel, SiblingType.Conditional, stmt, stmt.loc)
{
// </summary>
void CheckOutParameters (UsageVector vector, Location loc)
{
+ if (vector.Reachability.IsUnreachable)
+ return;
for (int i = 0; i < param_map.Count; i++) {
VariableInfo var = param_map [i];
public override bool AddReturnOrigin (UsageVector vector, Location loc)
{
- CheckOutParameters (vector, loc);
+ vector = vector.Clone ();
+ vector.Location = loc;
+ vector.Next = return_origins;
+ return_origins = vector;
return false;
}
return false;
}
- public Reachability End ()
+ protected override UsageVector Merge ()
{
- UsageVector result = Merge ();
+ for (UsageVector origin = return_origins; origin != null; origin = origin.Next)
+ CheckOutParameters (origin, origin.Location);
- Report.Debug (4, "MERGE TOP BLOCK", Location, result);
-
- if (!result.Reachability.AlwaysThrows && !result.Reachability.AlwaysHasBarrier)
- CheckOutParameters (result, Location);
+ UsageVector vector = base.Merge ();
+ CheckOutParameters (vector, Block.loc);
+ // Note: we _do_not_ merge in the return origins
+ return vector;
+ }
- return result.Reachability;
+ public Reachability End ()
+ {
+ return Merge ().Reachability;
}
}
public override bool AddBreakOrigin (UsageVector vector, Location loc)
{
+ vector = vector.Clone ();
if (finally_vector != null) {
- Report.Error (157, loc, "Control cannot leave the body of a finally clause");
+ vector.MergeChild (finally_vector, false);
+ int errors = Report.Errors;
+ Parent.AddBreakOrigin (vector, loc);
+ if (errors == Report.Errors)
+ Report.Error (157, loc, "Control cannot leave the body of a finally clause");
} else {
- vector = vector.Clone ();
vector.Location = loc;
vector.Next = break_origins;
break_origins = vector;
public override bool AddContinueOrigin (UsageVector vector, Location loc)
{
+ vector = vector.Clone ();
if (finally_vector != null) {
- Report.Error (157, loc, "Control cannot leave the body of a finally clause");
+ vector.MergeChild (finally_vector, false);
+ int errors = Report.Errors;
+ Parent.AddContinueOrigin (vector, loc);
+ if (errors == Report.Errors)
+ Report.Error (157, loc, "Control cannot leave the body of a finally clause");
} else {
- vector = vector.Clone ();
vector.Location = loc;
vector.Next = continue_origins;
continue_origins = vector;
public override bool AddReturnOrigin (UsageVector vector, Location loc)
{
+ vector = vector.Clone ();
if (finally_vector != null) {
- Report.Error (157, loc, "Control cannot leave the body of a finally clause");
+ vector.MergeChild (finally_vector, false);
+ int errors = Report.Errors;
+ Parent.AddReturnOrigin (vector, loc);
+ if (errors == Report.Errors)
+ Report.Error (157, loc, "Control cannot leave the body of a finally clause");
} else {
- vector = vector.Clone ();
vector.Location = loc;
vector.Next = return_origins;
return_origins = vector;
if (s != null)
throw new InternalErrorException ("Shouldn't get here");
- if (finally_vector != null)
- Report.Error (157, goto_stmt.loc, "Control cannot leave the body of a finally clause");
- else
- goto_origins = new GotoOrigin (vector.Clone (), goto_stmt, goto_origins);
+ vector = vector.Clone ();
+ if (finally_vector != null) {
+ vector.MergeChild (finally_vector, false);
+ int errors = Report.Errors;
+ Parent.AddGotoOrigin (vector, goto_stmt);
+ if (errors == Report.Errors)
+ Report.Error (157, goto_stmt.loc, "Control cannot leave the body of a finally clause");
+ } else {
+ goto_origins = new GotoOrigin (vector, goto_stmt, goto_origins);
+ }
return true;
}
for (UsageVector origin = break_origins; origin != null; origin = origin.Next) {
if (finally_vector != null)
origin.MergeChild (finally_vector, false);
- if (!origin.Reachability.IsUnreachable)
- Parent.AddBreakOrigin (origin, origin.Location);
+ Parent.AddBreakOrigin (origin, origin.Location);
}
for (UsageVector origin = continue_origins; origin != null; origin = origin.Next) {
if (finally_vector != null)
origin.MergeChild (finally_vector, false);
- if (!origin.Reachability.IsUnreachable)
- Parent.AddContinueOrigin (origin, origin.Location);
+ Parent.AddContinueOrigin (origin, origin.Location);
}
for (UsageVector origin = return_origins; origin != null; origin = origin.Next) {
if (finally_vector != null)
origin.MergeChild (finally_vector, false);
- if (!origin.Reachability.IsUnreachable)
- Parent.AddReturnOrigin (origin, origin.Location);
+ Parent.AddReturnOrigin (origin, origin.Location);
}
for (GotoOrigin origin = goto_origins; origin != null; origin = origin.Next) {
if (finally_vector != null)
origin.Vector.MergeChild (finally_vector, false);
- if (!origin.Vector.Reachability.IsUnreachable)
- Parent.AddGotoOrigin (origin.Vector, origin.GotoStmt);
+ Parent.AddGotoOrigin (origin.Vector, origin.GotoStmt);
}
return vector;
ArrayList non_public_fields = new ArrayList ();
if (fields != null) {
- foreach (FieldMember field in fields) {
+ foreach (FieldBase field in fields) {
if ((field.ModFlags & Modifiers.STATIC) != 0)
continue;
if ((field.ModFlags & Modifiers.PUBLIC) != 0)
Fields = new FieldInfo [Count];
public_fields.CopyTo (Fields, 0);
non_public_fields.CopyTo (Fields, CountPublic);
+#if GMCS_SOURCE
+ } else if (type is GenericTypeParameterBuilder) {
+ CountPublic = CountNonPublic = Count = 0;
+
+ Fields = new FieldInfo [0];
+#endif
} else {
FieldInfo[] public_fields = type.GetFields (
BindingFlags.Instance|BindingFlags.Public);
// </summary>
public class MyBitVector {
public readonly int Count;
- public MyBitVector InheritsFrom;
public static readonly MyBitVector Empty = new MyBitVector ();
- BitArray vector;
+ // Invariant: vector != null => vector.Count == Count
+ // Invariant: vector == null || shared == null
+ // i.e., at most one of 'vector' and 'shared' can be non-null. They can both be null -- that means all-ones
+ // The object in 'shared' cannot be modified, while 'vector' can be freely modified
+ BitArray vector, shared;
MyBitVector ()
{
- InheritsFrom = null;
- Count = 0;
+ shared = new BitArray (0, false);
}
public MyBitVector (MyBitVector InheritsFrom, int Count)
{
- if (InheritsFrom != null) {
- while (InheritsFrom.InheritsFrom != null)
- InheritsFrom = InheritsFrom.InheritsFrom;
- if (InheritsFrom.Count >= Count && InheritsFrom.vector == null)
- InheritsFrom = null;
- }
+ if (InheritsFrom != null)
+ shared = InheritsFrom.Shared;
- this.InheritsFrom = InheritsFrom;
this.Count = Count;
}
+ // Use this accessor to get a shareable copy of the underlying BitArray representation
+ BitArray Shared {
+ get {
+ // Post-condition: vector == null
+ if (shared == null) {
+ shared = vector;
+ vector = null;
+ }
+ return shared;
+ }
+ }
+
// <summary>
// Get/set bit `index' in the bit vector.
// </summary>
- public bool this [int index]
- {
+ 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];
- if (InheritsFrom == null)
+ if (shared == null)
return true;
- if (index < InheritsFrom.Count)
- return InheritsFrom [index];
+ if (index < shared.Count)
+ return shared [index];
return false;
}
// Performs an `or' operation on the bit vector. The `new_vector' may have a
// different size than the current one.
// </summary>
- private void Or (MyBitVector new_vector)
+ private MyBitVector Or (MyBitVector new_vector)
{
- int min = new_vector.Count;
+ if (Count == 0 || new_vector.Count == 0)
+ return this;
+
+ BitArray o = new_vector.vector != null ? new_vector.vector : new_vector.shared;
+
+ if (o == null) {
+ int n = new_vector.Count;
+ if (n < Count) {
+ for (int i = 0; i < n; ++i)
+ this [i] = true;
+ } else {
+ SetAll (true);
+ }
+ return this;
+ }
+
+ if (Count == o.Count) {
+ if (vector == null) {
+ if (shared == null)
+ return this;
+ initialize_vector ();
+ }
+ vector.Or (o);
+ return this;
+ }
+
+ int min = o.Count;
if (Count < min)
min = Count;
- for (int i = 0; i < min; i++)
- this [i] |= new_vector [i];
+ for (int i = 0; i < min; i++) {
+ if (o [i])
+ this [i] = true;
+ }
+
+ return this;
}
// <summary>
- // Perfonrms an `and' operation on the bit vector. The `new_vector' may have
+ // Performs an `and' operation on the bit vector. The `new_vector' may have
// a different size than the current one.
// </summary>
- private void And (MyBitVector new_vector)
+ private MyBitVector And (MyBitVector new_vector)
{
- int min = new_vector.Count;
+ if (Count == 0)
+ return this;
+
+ BitArray o = new_vector.vector != null ? new_vector.vector : new_vector.shared;
+
+ if (o == null) {
+ for (int i = new_vector.Count; i < Count; ++i)
+ this [i] = false;
+ return this;
+ }
+
+ if (o.Count == 0) {
+ SetAll (false);
+ return this;
+ }
+
+ if (Count == o.Count) {
+ if (vector == null) {
+ if (shared == null) {
+ shared = new_vector.Shared;
+ return this;
+ }
+ initialize_vector ();
+ }
+ vector.And (o);
+ return this;
+ }
+
+ int min = o.Count;
if (Count < min)
min = Count;
- for (int i = 0; i < min; i++)
- this [i] &= new_vector [i];
+ for (int i = 0; i < min; i++) {
+ if (! o [i])
+ this [i] = false;
+ }
for (int i = min; i < Count; i++)
this [i] = false;
+
+ return this;
}
- public static void And (ref MyBitVector target, MyBitVector vector)
+ public static MyBitVector operator & (MyBitVector a, MyBitVector b)
{
- if (vector == null)
- return;
- if (target == null)
- target = vector.Clone ();
+ if (a == b)
+ return a;
+ if (a == null)
+ return b.Clone ();
+ if (b == null)
+ return a.Clone ();
+ if (a.Count > b.Count)
+ return a.Clone ().And (b);
else
- target.And (vector);
+ return b.Clone ().And (a);
}
- public static void Or (ref MyBitVector target, MyBitVector vector)
+ public static MyBitVector operator | (MyBitVector a, MyBitVector b)
{
- if (target == null)
- return;
- if (vector == null)
- target.SetAll (true);
+ if (a == b)
+ return a;
+ if (a == null)
+ return new MyBitVector (null, b.Count);
+ if (b == null)
+ return new MyBitVector (null, a.Count);
+ if (a.Count > b.Count)
+ return a.Clone ().Or (b);
else
- target.Or (vector);
+ return b.Clone ().Or (a);
}
- // <summary>
- // This does a deep copy of the bit vector.
- // </summary>
public MyBitVector Clone ()
{
- if (Count == 0)
- return Empty;
- MyBitVector retval = new MyBitVector (this, Count);
- retval.initialize_vector ();
- return retval;
+ return Count == 0 ? Empty : new MyBitVector (this, Count);
}
public void SetAll (bool value)
{
- InheritsFrom = value ? null : Empty;
+ // Don't clobber Empty
+ if (Count == 0)
+ return;
+ shared = value ? null : Empty.Shared;
vector = null;
}
void initialize_vector ()
{
- if (InheritsFrom == null) {
+ // Post-condition: vector != null
+ if (shared == null) {
vector = new BitArray (Count, true);
return;
}
- vector = new BitArray (Count, false);
-
- int min = InheritsFrom.Count;
- if (min > Count)
- min = Count;
-
- for (int i = 0; i < min; i++)
- vector [i] = InheritsFrom [i];
-
- InheritsFrom = null;
+ vector = new BitArray (shared);
+ if (Count != vector.Count)
+ vector.Length = Count;
+ shared = null;
}
StringBuilder Dump (StringBuilder sb)
{
- if (vector == null)
- return InheritsFrom == null ? sb.Append ("/") : InheritsFrom.Dump (sb.Append ("="));
- for (int i = 0; i < Count; i++)
- sb.Append (this [i] ? "1" : "0");
+ BitArray dump = vector == null ? shared : vector;
+ if (dump == null)
+ return sb.Append ("/");
+ if (dump == shared)
+ sb.Append ("=");
+ for (int i = 0; i < dump.Count; i++)
+ sb.Append (dump [i] ? "1" : "0");
return sb;
}
projects / mono.git / blobdiff