/** @return complete, i.e., deep copy of this list */
public InstructionList copy() {
Map<InstructionHandle, InstructionHandle> map =
new HashMap<InstructionHandle, InstructionHandle>();
InstructionList il = new InstructionList();
/* Pass 1: Make copies of all instructions, append them to the new list
* and associate old instruction references with the new ones, i.e.,
* a 1:1 mapping.
*/
for (InstructionHandle ih = start; ih != null; ih = ih.next) {
Instruction i = ih.instruction;
Instruction c = i.copy(); // Use clone for shallow copy
if (c instanceof BranchInstruction) {
map.put(ih, il.append((BranchInstruction) c));
} else {
map.put(ih, il.append(c));
}
}
/* Pass 2: Update branch targets.
*/
InstructionHandle ih = start;
InstructionHandle ch = il.start;
while (ih != null) {
Instruction i = ih.instruction;
Instruction c = ch.instruction;
if (i instanceof BranchInstruction) {
BranchInstruction bi = (BranchInstruction) i;
BranchInstruction bc = (BranchInstruction) c;
InstructionHandle itarget = bi.getTarget(); // old target
// New target is in hash map
bc.setTarget(map.get(itarget));
if (bi instanceof Select) { // Either LOOKUPSWITCH or TABLESWITCH
InstructionHandle[] itargets = ((Select) bi).getTargets();
InstructionHandle[] ctargets = ((Select) bc).getTargets();
for (int j = 0; j < itargets.length; j++) { // Update all targets
ctargets[j] = map.get(itargets[j]);
}
}
}
ih = ih.next;
ch = ch.next;
}
return il;
}
/**
* Redirect all references from old_target to new_target, i.e., update targets of branch
* instructions.
*
* @param old_target the old target instruction handle
* @param new_target the new target instruction handle
*/
public void redirectBranches(InstructionHandle old_target, InstructionHandle new_target) {
for (InstructionHandle ih = start; ih != null; ih = ih.next) {
Instruction i = ih.getInstruction();
if (i instanceof BranchInstruction) {
BranchInstruction b = (BranchInstruction) i;
InstructionHandle target = b.getTarget();
if (target == old_target) {
b.setTarget(new_target);
}
if (b instanceof Select) { // Either LOOKUPSWITCH or TABLESWITCH
InstructionHandle[] targets = ((Select) b).getTargets();
for (int j = 0; j < targets.length; j++) {
if (targets[j] == old_target) {
((Select) b).setTarget(j, new_target);
}
}
}
}
}
}