serp.bytecode.LoadInstruction Maven / Gradle / Ivy
package serp.bytecode;
import java.io.*;
import serp.bytecode.visitor.*;
/**
* Loads a value from the locals table to the stack.
*
* @author Abe White
*/
public class LoadInstruction extends LocalVariableInstruction {
private static final Class[][] _mappings = new Class[][] {
{ byte.class, int.class },
{ boolean.class, int.class },
{ char.class, int.class },
{ short.class, int.class },
{ void.class, int.class },
};
String _type = null;
LoadInstruction(Code owner) {
super(owner);
}
LoadInstruction(Code owner, int opcode) {
super(owner, opcode);
}
int getLength() {
switch (getOpcode()) {
case Constants.ILOAD:
case Constants.LLOAD:
case Constants.FLOAD:
case Constants.DLOAD:
case Constants.ALOAD:
return super.getLength() + 1;
default:
return super.getLength();
}
}
public int getStackChange() {
switch (getOpcode()) {
case Constants.LLOAD:
case Constants.LLOAD0:
case Constants.LLOAD1:
case Constants.LLOAD2:
case Constants.LLOAD3:
case Constants.DLOAD:
case Constants.DLOAD0:
case Constants.DLOAD1:
case Constants.DLOAD2:
case Constants.DLOAD3:
return 2;
case Constants.NOP:
return 0;
default:
return 1;
}
}
public int getLogicalStackChange() {
switch (getOpcode()) {
case Constants.NOP:
return 0;
default:
return 1;
}
}
public String getTypeName() {
switch (getOpcode()) {
case Constants.ILOAD:
case Constants.ILOAD0:
case Constants.ILOAD1:
case Constants.ILOAD2:
case Constants.ILOAD3:
return int.class.getName();
case Constants.LLOAD:
case Constants.LLOAD0:
case Constants.LLOAD1:
case Constants.LLOAD2:
case Constants.LLOAD3:
return long.class.getName();
case Constants.FLOAD:
case Constants.FLOAD0:
case Constants.FLOAD1:
case Constants.FLOAD2:
case Constants.FLOAD3:
return float.class.getName();
case Constants.DLOAD:
case Constants.DLOAD0:
case Constants.DLOAD1:
case Constants.DLOAD2:
case Constants.DLOAD3:
return double.class.getName();
case Constants.ALOAD:
case Constants.ALOAD0:
case Constants.ALOAD1:
case Constants.ALOAD2:
case Constants.ALOAD3:
return Object.class.getName();
default:
return _type;
}
}
public TypedInstruction setType(String type) {
type = mapType(type, _mappings, true);
int local = getLocal();
int len = getLength();
// if an invalid type or local, revert to nop
if (type == null || local < 0) {
_type = type;
setOpcode(Constants.NOP);
} else {
// valid opcode, unset saved type
_type = null;
switch (type.charAt(0)) {
case 'i':
setOpcode((local > 3) ? Constants.ILOAD
: (Constants.ILOAD0 + local));
break;
case 'l':
setOpcode((local > 3) ? Constants.LLOAD
: (Constants.LLOAD0 + local));
break;
case 'f':
setOpcode((local > 3) ? Constants.FLOAD
: (Constants.FLOAD0 + local));
break;
case 'd':
setOpcode((local > 3) ? Constants.DLOAD
: (Constants.DLOAD0 + local));
break;
default:
setOpcode((local > 3) ? Constants.ALOAD
: (Constants.ALOAD0 + local));
}
}
if (len != getLength())
invalidateByteIndexes();
return this;
}
/**
* Equivalent to setLocal (0).setType (Object.class); the
* this ptr is always passed in local variable 0.
*
* @return this instruction, for method chaining
*/
public LoadInstruction setThis() {
return (LoadInstruction) setLocal(0).setType(Object.class);
}
/**
* Equivalent to getLocal () == 0 && getType () ==
* Object.class; the this ptr
* is always passed in local variable 0.
*/
public boolean isThis() {
return getLocal() == 0 && getType() == Object.class;
}
/**
* LoadInstructions are equal if the type they reference the same
* type and locals index or if either is unset.
*/
public boolean equalsInstruction(Instruction other) {
if (other == this)
return true;
if (!super.equalsInstruction(other))
return false;
String type = getTypeName();
String otherType = ((LoadInstruction) other).getTypeName();
return type == null || otherType == null || type.equals(otherType);
}
public void acceptVisit(BCVisitor visit) {
visit.enterLoadInstruction(this);
visit.exitLoadInstruction(this);
}
void read(Instruction orig) {
super.read(orig);
LoadInstruction ins = (LoadInstruction) orig;
_type = ins._type;
}
void read(DataInput in) throws IOException {
super.read(in);
switch (getOpcode()) {
case Constants.ILOAD:
case Constants.LLOAD:
case Constants.FLOAD:
case Constants.DLOAD:
case Constants.ALOAD:
setLocal(in.readUnsignedByte());
break;
}
}
void write(DataOutput out) throws IOException {
super.write(out);
switch (getOpcode()) {
case Constants.ILOAD:
case Constants.LLOAD:
case Constants.FLOAD:
case Constants.DLOAD:
case Constants.ALOAD:
out.writeByte(getLocal());
}
}
void calculateOpcode() {
// taken care of when setting type
setType(getTypeName());
}
void calculateLocal() {
switch (getOpcode()) {
case Constants.ILOAD0:
case Constants.LLOAD0:
case Constants.FLOAD0:
case Constants.DLOAD0:
case Constants.ALOAD0:
setLocal(0);
break;
case Constants.ILOAD1:
case Constants.LLOAD1:
case Constants.FLOAD1:
case Constants.DLOAD1:
case Constants.ALOAD1:
setLocal(1);
break;
case Constants.ILOAD2:
case Constants.LLOAD2:
case Constants.FLOAD2:
case Constants.DLOAD2:
case Constants.ALOAD2:
setLocal(2);
break;
case Constants.ILOAD3:
case Constants.LLOAD3:
case Constants.FLOAD3:
case Constants.DLOAD3:
case Constants.ALOAD3:
setLocal(3);
break;
}
}
}