/**
* Replace the previous instruction(s), from the end of the peephole window up to i with a new
* Instruction sequence. It will replace all the previous instructions through i. Must not be
* called with an index that falls outside of the peephole window.
*
* @param i the index of the previous instruction to replace. Follows the same indexing strategy
* as the previous() method 0 is the last instruction in the window, 1 is two instructions
* ago, up to PEEPHOLE_WINDOW_SIZE-1 which is the oldest instruction that can be replaced.
* @param insns The new instruction sequence to insert at i
*/
private void replace(int i, Instruction[] insns) {
if (insns.length == 0) return;
int size = instructions.size();
int idx = i + 1;
if (size >= idx) {
int realIdx = size - idx;
assert !indexBeforeLabel(realIdx)
: "Attempting to replace instruction sequence that spans a label";
// replace the instruction
InstructionInfo info = instructions.get(realIdx);
info.setInstruction(insns[0]);
// Delete any remaining instructions, saving the list of labelNexts from the last deleted
// instruction
List<Label> labelNexts = null;
for (int r = size - 1; r >= (realIdx + 1); --r) {
InstructionInfo temp = instructions.remove(r);
if (r == size - 1) {
// Save the labelNexts from the last deleted instruction
labelNexts = temp.getLabelNexts();
}
}
// Add the remaining instructions
for (int r = 1, l = insns.length; r < l; ++r) addInstruction(insns[r]);
if (labelNexts != null) {
// Apply any saved labelNexts to the last instruction added
for (Label l : labelNexts) labelNext(l);
}
} else {
assert false : "Trying to replace instructions that fall outside the peephole window";
}
}
