com.android.dx.rop.code.PlainInsn Java Examples

/**
 * Adds a move instruction after the phi insn block.
 *
 * @param result move destination
 * @param source move source
 */
public void addMoveToBeginning (RegisterSpec result, RegisterSpec source) {
    if (result.getReg() == source.getReg()) {
        // Sometimes we end up with no-op moves. Ignore them here.
        return;
    }

    RegisterSpecList sources = RegisterSpecList.make(source);
    NormalSsaInsn toAdd = new NormalSsaInsn(
            new PlainInsn(Rops.opMove(result.getType()),
                    SourcePosition.NO_INFO, result, sources), this);

    insns.add(getCountPhiInsns(), toAdd);
    movesFromPhisAtBeginning++;
}
 

/**
 * Adds a move instruction after the phi insn block.
 *
 * @param result move destination
 * @param source move source
 */
public void addMoveToBeginning (RegisterSpec result, RegisterSpec source) {
    if (result.getReg() == source.getReg()) {
        // Sometimes we end up with no-op moves. Ignore them here.
        return;
    }

    RegisterSpecList sources = RegisterSpecList.make(source);
    NormalSsaInsn toAdd = new NormalSsaInsn(
            new PlainInsn(Rops.opMove(result.getType()),
                    SourcePosition.NO_INFO, result, sources), this);

    insns.add(getCountPhiInsns(), toAdd);
    movesFromPhisAtBeginning++;
}
 

/**
 * 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 a move instruction after the phi insn block.
 *
 * @param result move destination
 * @param source move source
 */
public void addMoveToBeginning (RegisterSpec result, RegisterSpec source) {
    if (result.getReg() == source.getReg()) {
        // Sometimes we end up with no-op moves. Ignore them here.
        return;
    }

    RegisterSpecList sources = RegisterSpecList.make(source);
    NormalSsaInsn toAdd = new NormalSsaInsn(
            new PlainInsn(Rops.opMove(result.getType()),
                    SourcePosition.NO_INFO, result, sources), this);

    insns.add(getCountPhiInsns(), toAdd);
    movesFromPhisAtBeginning++;
}
 

/**
 * 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);
    }
}
 

/**
 * Replaces branches that have constant conditions with gotos
 */
private void replaceBranches() {
    for (SsaInsn insn : branchWorklist) {
        // Find if a successor block is never executed
        int oldSuccessor = -1;
        SsaBasicBlock block = insn.getBlock();
        int successorSize = block.getSuccessorList().size();
        for (int i = 0; i < successorSize; i++) {
            int successorBlock = block.getSuccessorList().get(i);
            if (!executableBlocks.get(successorBlock)) {
                oldSuccessor = successorBlock;
            }
        }

        /*
         * Prune branches that have already been handled and ones that no
         * longer have constant conditions (no nonexecutable successors)
         */
        if (successorSize != 2 || oldSuccessor == -1) continue;

        // Replace branch with goto
        Insn originalRopInsn = insn.getOriginalRopInsn();
        block.replaceLastInsn(new PlainInsn(Rops.GOTO,
            originalRopInsn.getPosition(), null, RegisterSpecList.EMPTY));
        block.removeSuccessor(oldSuccessor);
    }
}
 

/**
 * 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);
    }
}
 

/**
 * Replaces branches that have constant conditions with gotos
 */
private void replaceBranches() {
    for (SsaInsn insn : branchWorklist) {
        // Find if a successor block is never executed
        int oldSuccessor = -1;
        SsaBasicBlock block = insn.getBlock();
        int successorSize = block.getSuccessorList().size();
        for (int i = 0; i < successorSize; i++) {
            int successorBlock = block.getSuccessorList().get(i);
            if (!executableBlocks.get(successorBlock)) {
                oldSuccessor = successorBlock;
            }
        }

        /*
         * Prune branches that have already been handled and ones that no
         * longer have constant conditions (no nonexecutable successors)
         */
        if (successorSize != 2 || oldSuccessor == -1) continue;

        // Replace branch with goto
        Insn originalRopInsn = insn.getOriginalRopInsn();
        block.replaceLastInsn(new PlainInsn(Rops.GOTO,
            originalRopInsn.getPosition(), null, RegisterSpecList.EMPTY));
        block.removeSuccessor(oldSuccessor);
    }
}
 

/**
 * Replaces branches that have constant conditions with gotos
 */
private void replaceBranches() {
    for (SsaInsn insn : branchWorklist) {
        // Find if a successor block is never executed
        int oldSuccessor = -1;
        SsaBasicBlock block = insn.getBlock();
        int successorSize = block.getSuccessorList().size();
        for (int i = 0; i < successorSize; i++) {
            int successorBlock = block.getSuccessorList().get(i);
            if (!executableBlocks.get(successorBlock)) {
                oldSuccessor = successorBlock;
            }
        }

        /*
         * Prune branches that have already been handled and ones that no
         * longer have constant conditions (no nonexecutable successors)
         */
        if (successorSize != 2 || oldSuccessor == -1) continue;

        // Replace branch with goto
        Insn originalRopInsn = insn.getOriginalRopInsn();
        block.replaceLastInsn(new PlainInsn(Rops.GOTO,
            originalRopInsn.getPosition(), null, RegisterSpecList.EMPTY));
        block.removeSuccessor(oldSuccessor);
    }
}
 

/**
 * Deletes all insns in the set from this method.
 *
 * @param deletedInsns {@code non-null;} insns to delete
 */
public void deleteInsns(Set<SsaInsn> deletedInsns) {
    for (SsaBasicBlock block : getBlocks()) {
        ArrayList<SsaInsn> insns = block.getInsns();

        for (int i = insns.size() - 1; i >= 0; i--) {
            SsaInsn insn = insns.get(i);

            if (deletedInsns.contains(insn)) {
                onInsnRemoved(insn);
                insns.remove(i);
            }
        }

        // Check to see if we need to add a GOTO

        int insnsSz = insns.size();
        SsaInsn lastInsn = (insnsSz == 0) ? null : insns.get(insnsSz - 1);

        if (block != getExitBlock() && (insnsSz == 0
                || lastInsn.getOriginalRopInsn() == null
                || lastInsn.getOriginalRopInsn().getOpcode()
                    .getBranchingness() == Rop.BRANCH_NONE)) {
            // We managed to eat a throwable insn

            Insn gotoInsn = new PlainInsn(Rops.GOTO,
                    SourcePosition.NO_INFO, null, RegisterSpecList.EMPTY);
            insns.add(SsaInsn.makeFromRop(gotoInsn, block));

            // Remove secondary successors from this block
            BitSet succs = block.getSuccessors();
            for (int i = succs.nextSetBit(0); i >= 0;
                     i = succs.nextSetBit(i + 1)) {
                if (i != block.getPrimarySuccessorIndex()) {
                    block.removeSuccessor(i);
                }
            }
        }
    }
}
 

/**
 * Returns from a {@code void} method. After a return it is an error to
 * define further instructions after a return without first {@link #mark
 * marking} an existing unmarked label.
 */
public void returnVoid() {
    if (!method.returnType.equals(TypeId.VOID)) {
        throw new IllegalArgumentException("declared " + method.returnType
                + " but returned void");
    }
    addInstruction(new PlainInsn(Rops.RETURN_VOID, sourcePosition, null,
            RegisterSpecList.EMPTY));
}
 

/**
 * Returns the value in {@code result} to the calling method. After a return
 * it is an error to define further instructions after a return without
 * first {@link #mark marking} an existing unmarked label.
 */
public void returnValue(Local<?> result) {
    if (!result.type.equals(method.returnType)) {
        // TODO: this is probably too strict.
        throw new IllegalArgumentException("declared " + method.returnType
                + " but returned " + result.type);
    }
    addInstruction(new PlainInsn(Rops.opReturn(result.type.ropType), sourcePosition,
            null, RegisterSpecList.make(result.spec())));
}
 

/**
 * Compare floats or doubles. This stores -1 in {@code target} if {@code
 * a < b}, 0 in {@code target} if {@code a == b} and 1 in target if {@code
 * a > b}. This stores {@code nanValue} in {@code target} if either value
 * is {@code NaN}.
 */
public <T extends Number> void compareFloatingPoint(
        Local<Integer> target, Local<T> a, Local<T> b, int nanValue) {
    Rop rop;
    if (nanValue == 1) {
        rop = Rops.opCmpg(a.type.ropType);
    } else if (nanValue == -1) {
        rop = Rops.opCmpl(a.type.ropType);
    } else {
        throw new IllegalArgumentException("expected 1 or -1 but was " + nanValue);
    }
    addInstruction(new PlainInsn(rop, sourcePosition, target.spec(),
            RegisterSpecList.make(a.spec(), b.spec())));
}
 

/**
 * Check if an int or reference equals to zero. If the comparison is true,
 * execution jumps to {@code trueLabel}. If it is false, execution continues to
 * the next instruction.
 */
public <T> void compareZ(Comparison comparison, Label trueLabel, Local<?> a) {
    adopt(trueLabel);
    Rop rop = comparison.rop(StdTypeList.make(a.type.ropType));
    addInstruction(new PlainInsn(rop, sourcePosition, null,
            RegisterSpecList.make(a.spec())), trueLabel);
}
 

/**
 * Compare ints or references. If the comparison is true, execution jumps to
 * {@code trueLabel}. If it is false, execution continues to the next
 * instruction.
 */
public <T> void compare(Comparison comparison, Label trueLabel, Local<T> a, Local<T> b) {
    adopt(trueLabel);
    Rop rop = comparison.rop(StdTypeList.make(a.type.ropType, b.type.ropType));
    addInstruction(new PlainInsn(rop, sourcePosition, null,
            RegisterSpecList.make(a.spec(), b.spec())), trueLabel);
}
 

/**
 * Compare ints or references. If the comparison is true, execution jumps to
 * {@code trueLabel}. If it is false, execution continues to the next
 * instruction.
 */
public <T> void compare(Comparison comparison, Label trueLabel, Local<T> a, Local<T> b) {
    adopt(trueLabel);
    Rop rop = comparison.rop(StdTypeList.make(a.type.ropType, b.type.ropType));
    addInstruction(new PlainInsn(rop, sourcePosition, null,
            RegisterSpecList.make(a.spec(), b.spec())), trueLabel);
}
 

/**
 * Check if an int or reference equals to zero. If the comparison is true,
 * execution jumps to {@code trueLabel}. If it is false, execution continues to
 * the next instruction.
 */
public <T> void compareZ(Comparison comparison, Label trueLabel, Local<?> a) {
    adopt(trueLabel);
    Rop rop = comparison.rop(StdTypeList.make(a.type.ropType));
    addInstruction(new PlainInsn(rop, sourcePosition, null,
            RegisterSpecList.make(a.spec())), trueLabel);
}
 

/**
 * Compare floats or doubles. This stores -1 in {@code target} if {@code
 * a < b}, 0 in {@code target} if {@code a == b} and 1 in target if {@code
 * a > b}. This stores {@code nanValue} in {@code target} if either value
 * is {@code NaN}.
 */
public <T extends Number> void compareFloatingPoint(
        Local<Integer> target, Local<T> a, Local<T> b, int nanValue) {
    Rop rop;
    if (nanValue == 1) {
        rop = Rops.opCmpg(a.type.ropType);
    } else if (nanValue == -1) {
        rop = Rops.opCmpl(a.type.ropType);
    } else {
        throw new IllegalArgumentException("expected 1 or -1 but was " + nanValue);
    }
    addInstruction(new PlainInsn(rop, sourcePosition, target.spec(),
            RegisterSpecList.make(a.spec(), b.spec())));
}
 

/**
 * Deletes all insns in the set from this method.
 *
 * @param deletedInsns {@code non-null;} insns to delete
 */
public void deleteInsns(Set<SsaInsn> deletedInsns) {
    for (SsaBasicBlock block : getBlocks()) {
        ArrayList<SsaInsn> insns = block.getInsns();

        for (int i = insns.size() - 1; i >= 0; i--) {
            SsaInsn insn = insns.get(i);

            if (deletedInsns.contains(insn)) {
                onInsnRemoved(insn);
                insns.remove(i);
            }
        }

        // Check to see if we need to add a GOTO

        int insnsSz = insns.size();
        SsaInsn lastInsn = (insnsSz == 0) ? null : insns.get(insnsSz - 1);

        if (block != getExitBlock() && (insnsSz == 0
                || lastInsn.getOriginalRopInsn() == null
                || lastInsn.getOriginalRopInsn().getOpcode()
                    .getBranchingness() == Rop.BRANCH_NONE)) {
            // We managed to eat a throwable insn

            Insn gotoInsn = new PlainInsn(Rops.GOTO,
                    SourcePosition.NO_INFO, null, RegisterSpecList.EMPTY);
            insns.add(SsaInsn.makeFromRop(gotoInsn, block));

            // Remove secondary successors from this block
            BitSet succs = block.getSuccessors();
            for (int i = succs.nextSetBit(0); i >= 0;
                     i = succs.nextSetBit(i + 1)) {
                if (i != block.getPrimarySuccessorIndex()) {
                    block.removeSuccessor(i);
                }
            }
        }
    }
}
 

/**
 * Returns from a {@code void} method. After a return it is an error to
 * define further instructions after a return without first {@link #mark
 * marking} an existing unmarked label.
 */
public void returnVoid() {
    if (!method.returnType.equals(TypeId.VOID)) {
        throw new IllegalArgumentException("declared " + method.returnType
                + " but returned void");
    }
    addInstruction(new PlainInsn(Rops.RETURN_VOID, sourcePosition, null,
            RegisterSpecList.EMPTY));
}
 

/**
 * Returns the value in {@code result} to the calling method. After a return
 * it is an error to define further instructions after a return without
 * first {@link #mark marking} an existing unmarked label.
 */
public void returnValue(Local<?> result) {
    if (!result.type.equals(method.returnType)) {
        // TODO: this is probably too strict.
        throw new IllegalArgumentException("declared " + method.returnType
                + " but returned " + result.type);
    }
    addInstruction(new PlainInsn(Rops.opReturn(result.type.ropType), sourcePosition,
            null, RegisterSpecList.make(result.spec())));
}
 

/**
 * Adds a move instruction after the phi insn block.
 *
 * @param result move destination
 * @param source move source
 */
public void addMoveToBeginning (RegisterSpec result, RegisterSpec source) {
    if (result.getReg() == source.getReg()) {
        // Sometimes we end up with no-op moves. Ignore them here.
        return;
    }

    RegisterSpecList sources = RegisterSpecList.make(source);
    NormalSsaInsn toAdd = new NormalSsaInsn(
            new PlainInsn(Rops.opMove(result.getType()),
                    SourcePosition.NO_INFO, result, sources), this);

    insns.add(getCountPhiInsns(), toAdd);
    movesFromPhisAtBeginning++;
}
 

/**
 * Replaces branches that have constant conditions with gotos
 */
private void replaceBranches() {
    for (SsaInsn insn : branchWorklist) {
        // Find if a successor block is never executed
        int oldSuccessor = -1;
        SsaBasicBlock block = insn.getBlock();
        int successorSize = block.getSuccessorList().size();
        for (int i = 0; i < successorSize; i++) {
            int successorBlock = block.getSuccessorList().get(i);
            if (!executableBlocks.get(successorBlock)) {
                oldSuccessor = successorBlock;
            }
        }

        /*
         * Prune branches that have already been handled and ones that no
         * longer have constant conditions (no nonexecutable successors)
         */
        if (successorSize != 2 || oldSuccessor == -1) continue;

        // Replace branch with goto
        Insn originalRopInsn = insn.getOriginalRopInsn();
        block.replaceLastInsn(new PlainInsn(Rops.GOTO,
            originalRopInsn.getPosition(), null, RegisterSpecList.EMPTY));
        block.removeSuccessor(oldSuccessor);
    }
}
 

/**
 * 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);
    }
}
 

/** {@inheritDoc} */
public void visitPlainInsn(PlainInsn insn) {
    Rop rop = insn.getOpcode();
    if (rop.getOpcode() == RegOps.MARK_LOCAL) {
        /*
         * Ignore these. They're dealt with by
         * the LocalVariableAwareTranslationVisitor
         */
        return;
    }
    if (rop.getOpcode() == RegOps.MOVE_RESULT_PSEUDO) {
        // These get skipped
        return;
    }

    SourcePosition pos = insn.getPosition();
    Dop opcode = RopToDop.dopFor(insn);
    DalvInsn di;

    switch (rop.getBranchingness()) {
        case Rop.BRANCH_NONE:
        case Rop.BRANCH_RETURN:
        case Rop.BRANCH_THROW: {
            di = new SimpleInsn(opcode, pos, getRegs(insn));
            break;
        }
        case Rop.BRANCH_GOTO: {
            /*
             * Code in the main translation loop will emit a
             * goto if necessary (if the branch isn't to the
             * immediately subsequent block).
             */
            return;
        }
        case Rop.BRANCH_IF: {
            int target = block.getSuccessors().get(1);
            di = new TargetInsn(opcode, pos, getRegs(insn),
                                addresses.getStart(target));
            break;
        }
        default: {
            throw new RuntimeException("shouldn't happen");
        }
    }

    addOutput(di);
}
 

/**
 * Adds a move instruction to the end of this basic block, just
 * before the last instruction. If the result of the final instruction
 * is the source in question, then the move is placed at the beginning of
 * the primary successor block. This is for unversioned registers.
 *
 * @param result move destination
 * @param source move source
 */
public void addMoveToEnd(RegisterSpec result, RegisterSpec source) {

    if (result.getReg() == source.getReg()) {
        // Sometimes we end up with no-op moves. Ignore them here.
        return;
    }

    /*
     * The last Insn has to be a normal SSA insn: a phi can't branch
     * or return or cause an exception, etc.
     */
    NormalSsaInsn lastInsn;
    lastInsn = (NormalSsaInsn)insns.get(insns.size()-1);

    if (lastInsn.getResult() != null || lastInsn.getSources().size() > 0) {
        /*
         * The final insn in this block has a source or result
         * register, and the moves we may need to place and
         * schedule may interfere. We need to insert this
         * instruction at the beginning of the primary successor
         * block instead. We know this is safe, because when we
         * edge-split earlier, we ensured that each successor has
         * only us as a predecessor.
         */

        for (int i = successors.nextSetBit(0)
                ; i >= 0
                ; i = successors.nextSetBit(i + 1)) {

            SsaBasicBlock succ;

            succ = parent.getBlocks().get(i);
            succ.addMoveToBeginning(result, source);
        }
    } else {
        /*
         * We can safely add a move to the end of the block just
         * before the last instruction, because the final insn does
         * not assign to anything.
         */
        RegisterSpecList sources = RegisterSpecList.make(source);
        NormalSsaInsn toAdd = new NormalSsaInsn(
                new PlainInsn(Rops.opMove(result.getType()),
                        SourcePosition.NO_INFO, result, sources), this);

        insns.add(insns.size() - 1, toAdd);

        movesFromPhisAtEnd++;
    }
}
 

/**
 * Adds a move instruction to the end of this basic block, just
 * before the last instruction. If the result of the final instruction
 * is the source in question, then the move is placed at the beginning of
 * the primary successor block. This is for unversioned registers.
 *
 * @param result move destination
 * @param source move source
 */
public void addMoveToEnd(RegisterSpec result, RegisterSpec source) {

    if (result.getReg() == source.getReg()) {
        // Sometimes we end up with no-op moves. Ignore them here.
        return;
    }

    /*
     * The last Insn has to be a normal SSA insn: a phi can't branch
     * or return or cause an exception, etc.
     */
    NormalSsaInsn lastInsn;
    lastInsn = (NormalSsaInsn)insns.get(insns.size()-1);

    if (lastInsn.getResult() != null || lastInsn.getSources().size() > 0) {
        /*
         * The final insn in this block has a source or result
         * register, and the moves we may need to place and
         * schedule may interfere. We need to insert this
         * instruction at the beginning of the primary successor
         * block instead. We know this is safe, because when we
         * edge-split earlier, we ensured that each successor has
         * only us as a predecessor.
         */

        for (int i = successors.nextSetBit(0)
                ; i >= 0
                ; i = successors.nextSetBit(i + 1)) {

            SsaBasicBlock succ;

            succ = parent.getBlocks().get(i);
            succ.addMoveToBeginning(result, source);
        }
    } else {
        /*
         * We can safely add a move to the end of the block just
         * before the last instruction, because the final insn does
         * not assign to anything.
         */
        RegisterSpecList sources = RegisterSpecList.make(source);
        NormalSsaInsn toAdd = new NormalSsaInsn(
                new PlainInsn(Rops.opMove(result.getType()),
                        SourcePosition.NO_INFO, result, sources), this);

        insns.add(insns.size() - 1, toAdd);

        movesFromPhisAtEnd++;
    }
}
 

/**
       * {@inheritDoc}
       *
       * Move insns are treated as a simple mapping operation, and
       * will later be removed unless they represent a local variable
       * assignment. If they represent a local variable assignement, they
       * are preserved.
       */
      @Override
public void visitMoveInsn(NormalSsaInsn insn) {
          /*
           * For moves: copy propogate the move if we can, but don't
           * if we need to preserve local variable info and the
           * result has a different name than the source.
           */

          RegisterSpec ropResult = insn.getResult();
          int ropResultReg = ropResult.getReg();
          int ropSourceReg = insn.getSources().get(0).getReg();

          insn.mapSourceRegisters(mapper);
          int ssaSourceReg = insn.getSources().get(0).getReg();

          LocalItem sourceLocal
              = currentMapping[ropSourceReg].getLocalItem();
          LocalItem resultLocal = ropResult.getLocalItem();

          /*
           * A move from a register that's currently associated with a local
           * to one that will not be associated with a local does not need
           * to be preserved, but the local association should remain.
           * Hence, we inherit the sourceLocal where the resultLocal is null.
           */

          LocalItem newLocal
              = (resultLocal == null) ? sourceLocal : resultLocal;
          LocalItem associatedLocal = getLocalForNewReg(ssaSourceReg);

          /*
           * If we take the new local, will only one local have ever
           * been associated with this SSA reg?
           */
          boolean onlyOneAssociatedLocal
                  = associatedLocal == null || newLocal == null
                  || newLocal.equals(associatedLocal);

          /*
           * If we're going to copy-propogate, then the ssa register
           * spec that's going to go into the mapping is made up of
           * the source register number mapped from above, the type
           * of the result, and the name either from the result (if
           * specified) or inherited from the existing mapping.
           *
           * The move source has incomplete type information in null
           * object cases, so the result type is used.
           */
          RegisterSpec ssaReg
                  = RegisterSpec.makeLocalOptional(
                      ssaSourceReg, ropResult.getType(), newLocal);

          if (!Optimizer.getPreserveLocals() || (onlyOneAssociatedLocal
                  && equalsHandlesNulls(newLocal, sourceLocal)) &&
                  threshold == 0) {
              /*
               * We don't have to keep this move to preserve local
               * information. Either the name is the same, or the result
               * register spec is unnamed.
               */

              addMapping(ropResultReg, ssaReg);
          } else if (onlyOneAssociatedLocal && sourceLocal == null &&
                  threshold == 0) {
              /*
               * The register was previously unnamed. This means that a
               * local starts after it's first assignment in SSA form
               */

              RegisterSpecList ssaSources = RegisterSpecList.make(
                      RegisterSpec.make(ssaReg.getReg(),
                              ssaReg.getType(), newLocal));

              SsaInsn newInsn
                      = SsaInsn.makeFromRop(
                          new PlainInsn(Rops.opMarkLocal(ssaReg),
                          SourcePosition.NO_INFO, null, ssaSources),block);

              insnsToReplace.put(insn, newInsn);

              // Just map as above.
              addMapping(ropResultReg, ssaReg);
          } else {
              /*
               * Do not copy-propogate, since the two registers have
               * two different local-variable names.
               */
              processResultReg(insn);

              movesToKeep.add(insn);
          }
      }
 

/**
 * Inserts a move instruction for a specified SSA register before a
 * specified instruction, creating a new SSA register and adjusting the
 * interference graph in the process. The insn currently must be the
 * last insn in a block.
 *
 * @param insn {@code non-null;} insn to insert move before, must
 * be last insn in block
 * @param reg {@code non-null;} SSA register to duplicate
 * @return {@code non-null;} spec of new SSA register created by move
 */
protected final RegisterSpec insertMoveBefore(SsaInsn insn,
        RegisterSpec reg) {
    SsaBasicBlock block = insn.getBlock();
    ArrayList<SsaInsn> insns = block.getInsns();
    int insnIndex = insns.indexOf(insn);

    if (insnIndex < 0) {
        throw new IllegalArgumentException (
                "specified insn is not in this block");
    }

    if (insnIndex != insns.size() - 1) {
        /*
         * Presently, the interference updater only works when
         * adding before the last insn, and the last insn must have no
         * result
         */
        throw new IllegalArgumentException(
                "Adding move here not supported:" + insn.toHuman());
    }

    /*
     * Get new register and make new move instruction.
     */

    // The new result must not have an associated local variable.
    RegisterSpec newRegSpec = RegisterSpec.make(ssaMeth.makeNewSsaReg(),
            reg.getTypeBearer());

    SsaInsn toAdd = SsaInsn.makeFromRop(
            new PlainInsn(Rops.opMove(newRegSpec.getType()),
                    SourcePosition.NO_INFO, newRegSpec,
                    RegisterSpecList.make(reg)), block);

    insns.add(insnIndex, toAdd);

    int newReg = newRegSpec.getReg();

    /*
     * Adjust interference graph based on what's live out of the current
     * block and what's used by the final instruction.
     */

    IntSet liveOut = block.getLiveOutRegs();
    IntIterator liveOutIter = liveOut.iterator();

    while (liveOutIter.hasNext()) {
        interference.add(newReg, liveOutIter.next());
    }

    // Everything that's a source in the last insn interferes.
    RegisterSpecList sources = insn.getSources();
    int szSources = sources.size();

    for (int i = 0; i < szSources; i++) {
        interference.add(newReg, sources.get(i).getReg());
    }

    ssaMeth.onInsnsChanged();

    return newRegSpec;
}
 

/**
 * Inserts a move instruction for a specified SSA register before a
 * specified instruction, creating a new SSA register and adjusting the
 * interference graph in the process. The insn currently must be the
 * last insn in a block.
 *
 * @param insn {@code non-null;} insn to insert move before, must
 * be last insn in block
 * @param reg {@code non-null;} SSA register to duplicate
 * @return {@code non-null;} spec of new SSA register created by move
 */
protected final RegisterSpec insertMoveBefore(SsaInsn insn,
        RegisterSpec reg) {
    SsaBasicBlock block = insn.getBlock();
    ArrayList<SsaInsn> insns = block.getInsns();
    int insnIndex = insns.indexOf(insn);

    if (insnIndex < 0) {
        throw new IllegalArgumentException (
                "specified insn is not in this block");
    }

    if (insnIndex != insns.size() - 1) {
        /*
         * Presently, the interference updater only works when
         * adding before the last insn, and the last insn must have no
         * result
         */
        throw new IllegalArgumentException(
                "Adding move here not supported:" + insn.toHuman());
    }

    /*
     * Get new register and make new move instruction.
     */

    // The new result must not have an associated local variable.
    RegisterSpec newRegSpec = RegisterSpec.make(ssaMeth.makeNewSsaReg(),
            reg.getTypeBearer());

    SsaInsn toAdd = SsaInsn.makeFromRop(
            new PlainInsn(Rops.opMove(newRegSpec.getType()),
                    SourcePosition.NO_INFO, newRegSpec,
                    RegisterSpecList.make(reg)), block);

    insns.add(insnIndex, toAdd);

    int newReg = newRegSpec.getReg();

    /*
     * Adjust interference graph based on what's live out of the current
     * block and what's used by the final instruction.
     */

    IntSet liveOut = block.getLiveOutRegs();
    IntIterator liveOutIter = liveOut.iterator();

    while (liveOutIter.hasNext()) {
        interference.add(newReg, liveOutIter.next());
    }

    // Everything that's a source in the last insn interferes.
    RegisterSpecList sources = insn.getSources();
    int szSources = sources.size();

    for (int i = 0; i < szSources; i++) {
        interference.add(newReg, sources.get(i).getReg());
    }

    ssaMeth.onInsnsChanged();

    return newRegSpec;
}