/**
* Rewrites a move instruction if it has 2 memory operands. One of the 2 memory operands must be a
* stack location operand. Move the SP to the appropriate location and use a push or pop
* instruction.
*
* @param s the instruction to rewrite
*/
private void rewriteMoveInstruction(Instruction s) {
// first attempt to mutate the move into a noop
if (mutateMoveToNop(s)) return;
Operand result = MIR_Move.getResult(s);
Operand val = MIR_Move.getValue(s);
if (result instanceof StackLocationOperand) {
if (val instanceof MemoryOperand || val instanceof StackLocationOperand) {
int offset = ((StackLocationOperand) result).getOffset();
byte size = ((StackLocationOperand) result).getSize();
offset = FPOffset2SPOffset(offset) + size;
moveESPBefore(s, offset);
MIR_UnaryNoRes.mutate(s, IA32_PUSH, val);
}
} else {
if (result instanceof MemoryOperand) {
if (val instanceof StackLocationOperand) {
int offset = ((StackLocationOperand) val).getOffset();
offset = FPOffset2SPOffset(offset);
moveESPBefore(s, offset);
MIR_Nullary.mutate(s, IA32_POP, result);
}
}
}
}
