/**
* Replaces the last insn in this block. The provided insn must have some branchingness.
*
* @param insn {@code non-null;} rop-form insn to add, which must branch.
*/
public void replaceLastInsn(Insn insn) {
if (insn.getOpcode().getBranchingness() == Rop.BRANCH_NONE) {
throw new IllegalArgumentException("last insn must branch");
}
SsaInsn oldInsn = insns.get(insns.size() - 1);
SsaInsn newInsn = SsaInsn.makeFromRop(insn, this);
insns.set(insns.size() - 1, newInsn);
parent.onInsnRemoved(oldInsn);
parent.onInsnAdded(newInsn);
}
/**
* Inserts mark-locals if necessary when changing a register. If the definition of {@code origReg}
* is associated with a local variable, then insert a mark-local for {@code newReg} just below it.
* We expect the definition of {@code origReg} to ultimately be removed by the dead code
* eliminator
*
* @param origReg {@code non-null;} original register
* @param newReg {@code non-null;} new register that will replace {@code origReg}
*/
private void fixLocalAssignment(RegisterSpec origReg, RegisterSpec newReg) {
for (SsaInsn use : ssaMeth.getUseListForRegister(origReg.getReg())) {
RegisterSpec localAssignment = use.getLocalAssignment();
if (localAssignment == null) {
continue;
}
if (use.getResult() == null) {
/*
* This is a mark-local. it will be updated when all uses are
* updated.
*/
continue;
}
LocalItem local = localAssignment.getLocalItem();
// Un-associate original use.
use.setResultLocal(null);
// Now add a mark-local to the new reg immediately after.
newReg = newReg.withLocalItem(local);
SsaInsn newInsn =
SsaInsn.makeFromRop(
new PlainInsn(
Rops.opMarkLocal(newReg),
SourcePosition.NO_INFO,
null,
RegisterSpecList.make(newReg)),
use.getBlock());
ArrayList<SsaInsn> insns = use.getBlock().getInsns();
insns.add(insns.indexOf(use) + 1, newInsn);
}
}
/**
* Adds an insn to the head of this basic block, just after any phi insns.
*
* @param insn {@code non-null;} rop-form insn to add
*/
public void addInsnToHead(Insn insn) {
SsaInsn newInsn = SsaInsn.makeFromRop(insn, this);
insns.add(getCountPhiInsns(), newInsn);
parent.onInsnAdded(newInsn);
}