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Last active August 29, 2015 14:07
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ValueRange Visitor
module d.semantic.valuerange;
import d.semantic.semantic;
import d.ir.type;
import d.ast.expression;
import d.ir.expression;
struct ValueRange {
double _min;
double _max;
bool isInRangeOf(ValueRange that) {
return (that._max>=_max && that._min<=_min);
}
bool isInRangeOf (TypeKind k) {
return isInRangeOf(rangeOf(k));
}
ValueRange opBinary (string op)(ValueRange rhs) {
static if (op=="-") {
return ValueRange(_min-rhs._max, _max-rhs._min);
} else static if (op=="+") {
return ValueRange(_min+rhs._min, _max+rhs._max);
} else
assert(0, "Not Implemented");
}
unittest {
assert(ValueRange(0,255)-ValueRange(128,128) == ValueRange(-128,127));
assert(ValueRange(3,3)+ValueRange(-5,2)==ValueRange(-2,5));
}
ValueRange merge (ValueRange rhs) {
import std.algorithm:max,min;
return ValueRange(min(_min, rhs._min), max(_max, rhs._max));
}
static ValueRange rangeOf(TypeKind t) {
if (t == TypeKind.Bool) {
return ValueRange(bool.min,bool.max);
} else if (t == TypeKind.Ubyte) {
return ValueRange (ubyte.min,ubyte.max);
} else if (t == TypeKind.Ushort) {
return ValueRange (ushort.min,ushort.max);
} else if (t == TypeKind.Uint) {
return ValueRange (uint.min,uint.max);
} else if (t == TypeKind.Ulong) {
return ValueRange (ulong.min,ulong.max);
} else if (t == TypeKind.Byte) {
return ValueRange (byte.min,byte.max);
} else if (t == TypeKind.Short) {
return ValueRange (short.min,short.max);
} else if (t == TypeKind.Int) {
return ValueRange (int.min,int.max);
} else if (t == TypeKind.Long) {
return ValueRange (long.min,cast(double)long.max);
}
assert(0,"Rangeof does not accept " ~ typeid(t).toString() );
}
}
struct ValueRangeVisitor {
SemanticPass pass;
this(SemanticPass pass)
{
this.pass = pass;
}
ValueRange visit(VariableExpression e) {
auto BType = peelAlias(e.type);
assert(typeid(BType.type) == typeid(BuiltinType));
return ValueRange.rangeOf((cast(BuiltinType) BType.type).kind);
}
ValueRange visit(AstBinaryExpression e) {
ValueRange lhs = visit(e.lhs);
ValueRange rhs = visit(e.rhs);
switch (e.op) with (BinaryOp) {
case Add : return lhs+rhs;
case Sub : return lhs-rhs;
default : assert(0, "BinaryOp " ~ e.toString(pass.context)~" not supported by ValueRangeVisitor" );
}
}
ValueRange visit(AstExpression e) {
return this.dispatch!(function ValueRange(AstExpression e) {
assert(0, "ValueRange " ~ typeid(e).toString() ~ " is unknown.");
})(e);
}
ValueRange visit(IntegerLiteral!false e) {
return ValueRange(e.value,e.value);
}
ValueRange visit(IntegerLiteral!true e) {
return ValueRange(e.value,e.value);
}
unittest {
import d.location;
import std.stdio;
auto il = new IntegerLiteral!false(Location.init,1,TypeKind.Int);
assert(ValueRangeVisitor().visit(il).isInRangeOf(TypeKind.Byte));
assert(ValueRangeVisitor().visit(il).isInRangeOf(TypeKind.Bool));
assert(ValueRangeVisitor().visit(new AstBinaryExpression(Location.init, BinaryOp.Sub, new IntegerLiteral!false(Location.init, 255, TypeKind.Uint),new IntegerLiteral!false(Location.init, 128, TypeKind.Int))).isInRangeOf(TypeKind.Byte));
assert(ValueRange.rangeOf(TypeKind.Ubyte).isInRangeOf(TypeKind.Short));
assert(!(ValueRange.rangeOf(TypeKind.Short).isInRangeOf(TypeKind.Byte)));
}
}
@deadalnix
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Also, VRP struct should work for integers as well. Using float here will have cause issues. Right now, SDC do not support floating point at all.

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