public override Element/*!*/ NontrivialMeet(Element/*!*/ first, Element/*!*/ second) {
//Contract.Requires(second != null);
//Contract.Requires(first != null);
Contract.Ensures(Contract.Result<Element>() != null);
Elt a = (Elt)first;
Elt b = (Elt)second;
Contract.Assert(a.what != What.Bottom && b.what != What.Bottom);
if (a.what == What.Exact && b.what == What.Exact) {
Contract.Assert(a.ty != null && b.ty != null);
if (factory.IsTypeEqual(a.ty, b.ty)) {
return a;
} else {
return Bottom;
}
} else if (a.what == What.Exact || b.what == What.Exact) {
// One is Bounds, the other Exact. Make b be the Bounds one.
if (a.what == What.Bounds) {
Elt tmp = a;
a = b;
b = tmp;
}
Contract.Assert(a.what == What.Exact && b.what == What.Bounds);
// Check the exact type against all bounds. If the exact type is more restrictive
// than all bounds, then return it. If some bound is not met by the exact type, return
// bottom.
Contract.Assert(a.ty != null);
if (b.ty != null && !factory.IsSubType(a.ty, b.ty)) {
return Bottom;
}
if (b.manyBounds != null) {
foreach (IExpr/*!*/ bound in b.manyBounds) {
Contract.Assert(bound != null);
if (!factory.IsSubType(a.ty, bound)) {
return Bottom;
}
}
}
return a;
} else {
// Both operands are Bounds.
Contract.Assert(a.what == What.Bounds && b.what == What.Bounds);
// Take all the bounds, but prune those bounds that follow from others.
Contract.Assert(1 <= a.BoundsCount && 1 <= b.BoundsCount); // a preconditions is that neither operand is Top
int n = a.BoundsCount + b.BoundsCount;
// Special case: a and b each has exactly one bound
if (n == 2) {
Contract.Assert(a.ty != null && b.ty != null);
if (factory.IsSubType(a.ty, b.ty)) {
// a is more restrictive
return a;
} else if (factory.IsSubType(b.ty, a.ty)) {
// b is more restrictive
return b;
} else {
IExpr[]/*!*/ bounds = new IExpr[2];
bounds[0] = a.ty;
bounds[1] = b.ty;
return new Elt(bounds);
}
}
// General case
ArrayList /*IExpr*/ allBounds = new ArrayList /*IExpr*/ (n);
if (a.ty != null) {
allBounds.Add(a.ty);
} else {
allBounds.AddRange(cce.NonNull(a.manyBounds));
}
int bStart = allBounds.Count;
if (b.ty != null) {
allBounds.Add(b.ty);
} else {
allBounds.AddRange(cce.NonNull(b.manyBounds));
}
for (int i = 0; i < bStart; i++) {
IExpr/*!*/ aBound = cce.NonNull((IExpr)allBounds[i]);
for (int j = bStart; j < allBounds.Count; j++) {
IExpr bBound = (IExpr/*! Wouldn't the non-null typing in the original Spec# code had made bBound never null,
* thus negating the need for the continue statement?*/
)allBounds[j];
if (bBound == null) {
continue;
} else if (factory.IsSubType(aBound, bBound)) {
// a is more restrictive, so blot out the b bound
allBounds[j] = null;
n--;
} else if (factory.IsSubType(bBound, aBound)) {
// b is more restrictive, so blot out the a bound
allBounds[i] = null;
n--;
goto CONTINUE_OUTER_LOOP;
}
}
CONTINUE_OUTER_LOOP: {
}
}
Contract.Assert(1 <= n);
return new Elt(allBounds, n);
}
}
public override Element /*!*/ NontrivialMeet(Element /*!*/ first, Element /*!*/ second)
{
//Contract.Requires(second != null);
//Contract.Requires(first != null);
Contract.Ensures(Contract.Result <Element>() != null);
Elt a = (Elt)first;
Elt b = (Elt)second;
Contract.Assert(a.what != What.Bottom && b.what != What.Bottom);
if (a.what == What.Exact && b.what == What.Exact)
{
Contract.Assert(a.ty != null && b.ty != null);
if (factory.IsTypeEqual(a.ty, b.ty))
{
return(a);
}
else
{
return(Bottom);
}
}
else if (a.what == What.Exact || b.what == What.Exact)
{
// One is Bounds, the other Exact. Make b be the Bounds one.
if (a.what == What.Bounds)
{
Elt tmp = a;
a = b;
b = tmp;
}
Contract.Assert(a.what == What.Exact && b.what == What.Bounds);
// Check the exact type against all bounds. If the exact type is more restrictive
// than all bounds, then return it. If some bound is not met by the exact type, return
// bottom.
Contract.Assert(a.ty != null);
if (b.ty != null && !factory.IsSubType(a.ty, b.ty))
{
return(Bottom);
}
if (b.manyBounds != null)
{
foreach (IExpr /*!*/ bound in b.manyBounds)
{
Contract.Assert(bound != null);
if (!factory.IsSubType(a.ty, bound))
{
return(Bottom);
}
}
}
return(a);
}
else
{
// Both operands are Bounds.
Contract.Assert(a.what == What.Bounds && b.what == What.Bounds);
// Take all the bounds, but prune those bounds that follow from others.
Contract.Assert(1 <= a.BoundsCount && 1 <= b.BoundsCount); // a preconditions is that neither operand is Top
int n = a.BoundsCount + b.BoundsCount;
// Special case: a and b each has exactly one bound
if (n == 2)
{
Contract.Assert(a.ty != null && b.ty != null);
if (factory.IsSubType(a.ty, b.ty))
{
// a is more restrictive
return(a);
}
else if (factory.IsSubType(b.ty, a.ty))
{
// b is more restrictive
return(b);
}
else
{
IExpr[] /*!*/ bounds = new IExpr[2];
bounds[0] = a.ty;
bounds[1] = b.ty;
return(new Elt(bounds));
}
}
// General case
ArrayList /*IExpr*/ allBounds = new ArrayList/*IExpr*/ (n);
if (a.ty != null)
{
allBounds.Add(a.ty);
}
else
{
allBounds.AddRange(cce.NonNull(a.manyBounds));
}
int bStart = allBounds.Count;
if (b.ty != null)
{
allBounds.Add(b.ty);
}
else
{
allBounds.AddRange(cce.NonNull(b.manyBounds));
}
for (int i = 0; i < bStart; i++)
{
IExpr /*!*/ aBound = cce.NonNull((IExpr)allBounds[i]);
for (int j = bStart; j < allBounds.Count; j++)
{
IExpr bBound = (IExpr/*! Wouldn't the non-null typing in the original Spec# code had made bBound never null,
* thus negating the need for the continue statement?*/
)allBounds[j];
if (bBound == null)
{
continue;
}
else if (factory.IsSubType(aBound, bBound))
{
// a is more restrictive, so blot out the b bound
allBounds[j] = null;
n--;
}
else if (factory.IsSubType(bBound, aBound))
{
// b is more restrictive, so blot out the a bound
allBounds[i] = null;
n--;
goto CONTINUE_OUTER_LOOP;
}
}
CONTINUE_OUTER_LOOP : {
}
}
Contract.Assert(1 <= n);
return(new Elt(allBounds, n));
}
}
public override Element/*!*/ NontrivialJoin(Element/*!*/ first, Element/*!*/ second) {
//Contract.Requires(second != null);
//Contract.Requires(first != null);
Contract.Ensures(Contract.Result<Element>() != null);
Elt a = (Elt)first;
Elt b = (Elt)second;
Contract.Assert(a.what != What.Bottom && b.what != What.Bottom);
if (a.what == What.Exact && b.what == What.Exact) {
Contract.Assert(a.ty != null && b.ty != null);
if (factory.IsTypeEqual(a.ty, b.ty)) {
return a;
} else {
return new Elt(What.Bounds, factory.JoinTypes(a.ty, b.ty));
}
}
// The result is going to be a Bounds, since at least one of the operands is a Bounds.
Contract.Assert(1 <= a.BoundsCount && 1 <= b.BoundsCount); // a preconditions is that neither operand is Top
int n = a.BoundsCount + b.BoundsCount;
// Special case: a and b each has exactly one bound
if (n == 2) {
Contract.Assert(a.ty != null && b.ty != null);
IExpr join = factory.JoinTypes(a.ty, b.ty);
Contract.Assert(join != null);
if (join == a.ty && a.what == What.Bounds) {
return a;
} else if (join == b.ty && b.what == What.Bounds) {
return b;
} else {
return new Elt(What.Bounds, join);
}
}
// General case
ArrayList /*IExpr*/ allBounds = new ArrayList /*IExpr*/ (n); // final size
ArrayList /*IExpr!*/ result = new ArrayList /*IExpr!*/ (n); // a guess at the size, but could be as big as size(a)*size(b)
if (a.ty != null) {
allBounds.Add(a.ty);
} else {
allBounds.AddRange(cce.NonNull(a.manyBounds));
}
int bStart = allBounds.Count;
if (b.ty != null) {
allBounds.Add(b.ty);
} else {
allBounds.AddRange(cce.NonNull(b.manyBounds));
}
// compute the join of each pair, putting non-redundant joins into "result"
for (int i = 0; i < bStart; i++) {
IExpr/*!*/ aBound = cce.NonNull((IExpr/*!*/)allBounds[i]);
for (int j = bStart; j < allBounds.Count; j++) {
IExpr/*!*/ bBound = (IExpr/*!*/)cce.NonNull(allBounds[j]);
IExpr/*!*/ join = factory.JoinTypes(aBound, bBound);
Contract.Assert(join != null);
int k = 0;
while (k < result.Count) {
IExpr/*!*/ r = (IExpr/*!*/)cce.NonNull(result[k]);
if (factory.IsSubType(join, r)) {
// "join" is more restrictive than a bound already placed in "result",
// so toss out "join" and compute the join of the next pair
goto NEXT_PAIR;
} else if (factory.IsSubType(r, join)) {
// "join" is less restrictive than a bound already placed in "result",
// so toss out that old bound
result.RemoveAt(k);
} else {
k++;
}
}
result.Add(join);
NEXT_PAIR: {
}
}
}
return new Elt(result, result.Count);
}
public override Element /*!*/ NontrivialJoin(Element /*!*/ first, Element /*!*/ second)
{
//Contract.Requires(second != null);
//Contract.Requires(first != null);
Contract.Ensures(Contract.Result <Element>() != null);
Elt a = (Elt)first;
Elt b = (Elt)second;
Contract.Assert(a.what != What.Bottom && b.what != What.Bottom);
if (a.what == What.Exact && b.what == What.Exact)
{
Contract.Assert(a.ty != null && b.ty != null);
if (factory.IsTypeEqual(a.ty, b.ty))
{
return(a);
}
else
{
return(new Elt(What.Bounds, factory.JoinTypes(a.ty, b.ty)));
}
}
// The result is going to be a Bounds, since at least one of the operands is a Bounds.
Contract.Assert(1 <= a.BoundsCount && 1 <= b.BoundsCount); // a preconditions is that neither operand is Top
int n = a.BoundsCount + b.BoundsCount;
// Special case: a and b each has exactly one bound
if (n == 2)
{
Contract.Assert(a.ty != null && b.ty != null);
IExpr join = factory.JoinTypes(a.ty, b.ty);
Contract.Assert(join != null);
if (join == a.ty && a.what == What.Bounds)
{
return(a);
}
else if (join == b.ty && b.what == What.Bounds)
{
return(b);
}
else
{
return(new Elt(What.Bounds, join));
}
}
// General case
ArrayList /*IExpr*/ allBounds = new ArrayList/*IExpr*/ (n); // final size
ArrayList /*IExpr!*/ result = new ArrayList/*IExpr!*/ (n); // a guess at the size, but could be as big as size(a)*size(b)
if (a.ty != null)
{
allBounds.Add(a.ty);
}
else
{
allBounds.AddRange(cce.NonNull(a.manyBounds));
}
int bStart = allBounds.Count;
if (b.ty != null)
{
allBounds.Add(b.ty);
}
else
{
allBounds.AddRange(cce.NonNull(b.manyBounds));
}
// compute the join of each pair, putting non-redundant joins into "result"
for (int i = 0; i < bStart; i++)
{
IExpr /*!*/ aBound = cce.NonNull((IExpr /*!*/)allBounds[i]);
for (int j = bStart; j < allBounds.Count; j++)
{
IExpr /*!*/ bBound = (IExpr /*!*/)cce.NonNull(allBounds[j]);
IExpr /*!*/ join = factory.JoinTypes(aBound, bBound);
Contract.Assert(join != null);
int k = 0;
while (k < result.Count)
{
IExpr /*!*/ r = (IExpr /*!*/)cce.NonNull(result[k]);
if (factory.IsSubType(join, r))
{
// "join" is more restrictive than a bound already placed in "result",
// so toss out "join" and compute the join of the next pair
goto NEXT_PAIR;
}
else if (factory.IsSubType(r, join))
{
// "join" is less restrictive than a bound already placed in "result",
// so toss out that old bound
result.RemoveAt(k);
}
else
{
k++;
}
}
result.Add(join);
NEXT_PAIR : {
}
}
}
return(new Elt(result, result.Count));
}