Java Code Examples for com.android.dx.rop.code.RegisterSpec#make()

/**
 * Replaces the instructions that define an array with equivalent registers.
 * For each entry in the array, a register is created, initialized to zero.
 * A mapping between this register and the corresponding array index is
 * added.
 *
 * @param def {@code non-null;} move result instruction for array
 * @param prev {@code non-null;} instruction for instantiating new array
 * @param length size of the new array
 * @param newRegs {@code non-null;} mapping of array indices to new
 * registers to be populated
 */
private void replaceDef(SsaInsn def, SsaInsn prev, int length,
                            ArrayList<RegisterSpec> newRegs) {
    Type resultType = def.getResult().getType();

    // Create new zeroed out registers for each element in the array
    for (int i = 0; i < length; i++) {
        Constant newZero = Zeroes.zeroFor(resultType.getComponentType());
        TypedConstant typedZero = (TypedConstant) newZero;
        RegisterSpec newReg =
            RegisterSpec.make(ssaMeth.makeNewSsaReg(), typedZero);
        newRegs.add(newReg);
        insertPlainInsnBefore(def, RegisterSpecList.EMPTY, newReg,
                                  RegOps.CONST, newZero);
    }
}
 

/**
 * Replaces the instructions that define an array with equivalent registers.
 * For each entry in the array, a register is created, initialized to zero.
 * A mapping between this register and the corresponding array index is
 * added.
 *
 * @param def {@code non-null;} move result instruction for array
 * @param prev {@code non-null;} instruction for instantiating new array
 * @param length size of the new array
 * @param newRegs {@code non-null;} mapping of array indices to new
 * registers to be populated
 */
private void replaceDef(SsaInsn def, SsaInsn prev, int length,
                            ArrayList<RegisterSpec> newRegs) {
    Type resultType = def.getResult().getType();

    // Create new zeroed out registers for each element in the array
    for (int i = 0; i < length; i++) {
        Constant newZero = Zeroes.zeroFor(resultType.getComponentType());
        TypedConstant typedZero = (TypedConstant) newZero;
        RegisterSpec newReg =
            RegisterSpec.make(ssaMeth.makeNewSsaReg(), typedZero);
        newRegs.add(newReg);
        insertPlainInsnBefore(def, RegisterSpecList.EMPTY, newReg,
                                  RegOps.CONST, newZero);
    }
}
 

/**
 * Gets the register spec to use to hold the object to synchronize on,
 * for a synchronized method.
 *
 * @return {@code non-null;} the register spec
 */
private RegisterSpec getSynchReg() {
    /*
     * We use the register that is just past the deepest possible
     * stack element, with a minimum of v1 since v0 is what's
     * always used to hold the caught exception when unwinding. We
     * don't need to do anything else special at this level, since
     * later passes will merely notice the highest register used
     * by explicit inspection.
     */
    int reg = getNormalRegCount();
    return RegisterSpec.make((reg < 1) ? 1 : reg, Type.OBJECT);
}
 

/**
 * Gets the register spec to use to hold the object to synchronize on,
 * for a synchronized method.
 *
 * @return {@code non-null;} the register spec
 */
private RegisterSpec getSynchReg() {
    /*
     * We use the register that is just past the deepest possible
     * stack element, with a minimum of v1 since v0 is what's
     * always used to hold the caught exception when unwinding. We
     * don't need to do anything else special at this level, since
     * later passes will merely notice the highest register used
     * by explicit inspection.
     */
    int reg = getNormalRegCount();
    return RegisterSpec.make((reg < 1) ? 1 : reg, Type.OBJECT);
}
 

/**
 * Replaces instructions that trigger an ArrayIndexOutofBounds exception
 * with an actual throw of the exception.
 *
 * @param insn {@code non-null;} instruction causing the exception
 * @param index {@code non-null;} index value that is out of bounds
 * @param deletedInsns {@code non-null;} set of instructions marked for
 * deletion
 */
private void insertExceptionThrow(SsaInsn insn, RegisterSpec index,
                                      HashSet<SsaInsn> deletedInsns) {
    // Create a new ArrayIndexOutOfBoundsException
    CstType exception =
        new CstType(Exceptions.TYPE_ArrayIndexOutOfBoundsException);
    insertThrowingInsnBefore(insn, RegisterSpecList.EMPTY, null,
                                 RegOps.NEW_INSTANCE, exception);

    // Add a successor block with a move result pseudo for the exception
    SsaBasicBlock currBlock = insn.getBlock();
    SsaBasicBlock newBlock =
        currBlock.insertNewSuccessor(currBlock.getPrimarySuccessor());
    SsaInsn newInsn = newBlock.getInsns().get(0);
    RegisterSpec newReg =
        RegisterSpec.make(ssaMeth.makeNewSsaReg(), exception);
    insertPlainInsnBefore(newInsn, RegisterSpecList.EMPTY, newReg,
                              RegOps.MOVE_RESULT_PSEUDO, null);

    // Add another successor block to initialize the exception
    SsaBasicBlock newBlock2 =
        newBlock.insertNewSuccessor(newBlock.getPrimarySuccessor());
    SsaInsn newInsn2 = newBlock2.getInsns().get(0);
    CstNat newNat = new CstNat(new CstString("<init>"), new CstString("(I)V"));
    CstMethodRef newRef = new CstMethodRef(exception, newNat);
    insertThrowingInsnBefore(newInsn2, RegisterSpecList.make(newReg, index),
                                 null, RegOps.INVOKE_DIRECT, newRef);
    deletedInsns.add(newInsn2);

    // Add another successor block to throw the new exception
    SsaBasicBlock newBlock3 =
        newBlock2.insertNewSuccessor(newBlock2.getPrimarySuccessor());
    SsaInsn newInsn3 = newBlock3.getInsns().get(0);
    insertThrowingInsnBefore(newInsn3, RegisterSpecList.make(newReg), null,
                                 RegOps.THROW, null);
    newBlock3.replaceSuccessor(newBlock3.getPrimarySuccessorIndex(),
                                   ssaMeth.getExitBlock().getIndex());
    deletedInsns.add(newInsn3);
}
 

/**
 * Makes a phi insn with a void result type.
 *
 * @param resultReg the result register for this phi insn.
 * @param block block containing this insn.
 */
public PhiInsn(final int resultReg, final SsaBasicBlock block) {
    /*
     * The result type here is bogus: The type depends on the
     * operand and will be derived later.
     */
    super(RegisterSpec.make(resultReg, Type.VOID), block);
    ropResultReg = resultReg;
}
 

/**
 * Gets the register spec to use to hold the object to synchronize on,
 * for a synchronized method.
 *
 * @return {@code non-null;} the register spec
 */
private RegisterSpec getSynchReg() {
    /*
     * We use the register that is just past the deepest possible
     * stack element, with a minimum of v1 since v0 is what's
     * always used to hold the caught exception when unwinding. We
     * don't need to do anything else special at this level, since
     * later passes will merely notice the highest register used
     * by explicit inspection.
     */
    int reg = getNormalRegCount();
    return RegisterSpec.make((reg < 1) ? 1 : reg, Type.OBJECT);
}
 

/**
 * Makes a phi insn with a void result type.
 *
 * @param resultReg the result register for this phi insn.
 * @param block block containing this insn.
 */
public PhiInsn(final int resultReg, final SsaBasicBlock block) {
    /*
     * The result type here is bogus: The type depends on the
     * operand and will be derived later.
     */
    super(RegisterSpec.make(resultReg, Type.VOID), block);
    ropResultReg = resultReg;
}
 

/**
 * Replaces instructions that trigger an ArrayIndexOutofBounds exception
 * with an actual throw of the exception.
 *
 * @param insn {@code non-null;} instruction causing the exception
 * @param index {@code non-null;} index value that is out of bounds
 * @param deletedInsns {@code non-null;} set of instructions marked for
 * deletion
 */
private void insertExceptionThrow(SsaInsn insn, RegisterSpec index,
                                      HashSet<SsaInsn> deletedInsns) {
    // Create a new ArrayIndexOutOfBoundsException
    CstType exception =
        new CstType(Exceptions.TYPE_ArrayIndexOutOfBoundsException);
    insertThrowingInsnBefore(insn, RegisterSpecList.EMPTY, null,
                                 RegOps.NEW_INSTANCE, exception);

    // Add a successor block with a move result pseudo for the exception
    SsaBasicBlock currBlock = insn.getBlock();
    SsaBasicBlock newBlock =
        currBlock.insertNewSuccessor(currBlock.getPrimarySuccessor());
    SsaInsn newInsn = newBlock.getInsns().get(0);
    RegisterSpec newReg =
        RegisterSpec.make(ssaMeth.makeNewSsaReg(), exception);
    insertPlainInsnBefore(newInsn, RegisterSpecList.EMPTY, newReg,
                              RegOps.MOVE_RESULT_PSEUDO, null);

    // Add another successor block to initialize the exception
    SsaBasicBlock newBlock2 =
        newBlock.insertNewSuccessor(newBlock.getPrimarySuccessor());
    SsaInsn newInsn2 = newBlock2.getInsns().get(0);
    CstNat newNat = new CstNat(new CstString("<init>"), new CstString("(I)V"));
    CstMethodRef newRef = new CstMethodRef(exception, newNat);
    insertThrowingInsnBefore(newInsn2, RegisterSpecList.make(newReg, index),
                                 null, RegOps.INVOKE_DIRECT, newRef);
    deletedInsns.add(newInsn2);

    // Add another successor block to throw the new exception
    SsaBasicBlock newBlock3 =
        newBlock2.insertNewSuccessor(newBlock2.getPrimarySuccessor());
    SsaInsn newInsn3 = newBlock3.getInsns().get(0);
    insertThrowingInsnBefore(newInsn3, RegisterSpecList.make(newReg), null,
                                 RegOps.THROW, null);
    newBlock3.replaceSuccessor(newBlock3.getPrimarySuccessorIndex(),
                                   ssaMeth.getExitBlock().getIndex());
    deletedInsns.add(newInsn3);
}
 

/**
 * Makes a phi insn with a void result type.
 *
 * @param resultReg the result register for this phi insn.
 * @param block block containing this insn.
 */
public PhiInsn(final int resultReg, final SsaBasicBlock block) {
    /*
     * The result type here is bogus: The type depends on the
     * operand and will be derived later.
     */
    super(RegisterSpec.make(resultReg, Type.VOID), block);
    ropResultReg = resultReg;
}
 

/**
 * Makes a phi insn with a void result type.
 *
 * @param resultReg the result register for this phi insn.
 * @param block block containing this insn.
 */
public PhiInsn(final int resultReg, final SsaBasicBlock block) {
    /*
     * The result type here is bogus: The type depends on the
     * operand and will be derived later.
     */
    super(RegisterSpec.make(resultReg, Type.VOID), block);
    ropResultReg = resultReg;
}
 

/** {@inheritDoc} */
@Override
public void visitPlainCstInsn(PlainCstInsn insn) {
    SourcePosition pos = insn.getPosition();
    Dop opcode = RopToDop.dopFor(insn);
    Rop rop = insn.getOpcode();
    int ropOpcode = rop.getOpcode();
    DalvInsn di;

    if (rop.getBranchingness() != Rop.BRANCH_NONE) {
        throw new RuntimeException("shouldn't happen");
    }

    if (ropOpcode == RegOps.MOVE_PARAM) {
        if (!paramsAreInOrder) {
            /*
             * Parameters are not in order at the top of the reg space.
             * We need to add moves.
             */

            RegisterSpec dest = insn.getResult();
            int param =
                ((CstInteger) insn.getConstant()).getValue();
            RegisterSpec source =
                RegisterSpec.make(regCount - paramSize + param,
                        dest.getType());
            di = new SimpleInsn(opcode, pos,
                                RegisterSpecList.make(dest, source));
            addOutput(di);
        }
    } else {
        // No moves required for the parameters
        RegisterSpecList regs = getRegs(insn);
        di = new CstInsn(opcode, pos, regs, insn.getConstant());
        addOutput(di);
    }
}
 

/**
 * 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;
}
 

/**
 * Constructs an instance of the renamer
 *
 * @param ssaMeth {@code non-null;} un-renamed SSA method that will
 * be renamed.
 */
public SsaRenamer(SsaMethod ssaMeth) {
    ropRegCount = ssaMeth.getRegCount();

    this.ssaMeth = ssaMeth;

    /*
     * Reserve the first N registers in the SSA register space for
     * "version 0" registers.
     */
    nextSsaReg = ropRegCount;
    threshold = 0;
    startsForBlocks = new RegisterSpec[ssaMeth.getBlocks().size()][];

    ssaRegToLocalItems = new ArrayList<LocalItem>();

    if (DEBUG) {
        ssaRegToRopReg = new IntList(ropRegCount);
    }

    /*
     * Appel 19.7
     *
     * Initialization:
     *   for each variable a        // register i
     *      Count[a] <- 0           // nextSsaReg, flattened
     *      Stack[a] <- 0           // versionStack
     *      push 0 onto Stack[a]
     *
     */

    // top entry for the version stack is version 0
    RegisterSpec[] initialRegMapping = new RegisterSpec[ropRegCount];
    for (int i = 0; i < ropRegCount; i++) {
        // everyone starts with a version 0 register
        initialRegMapping[i] = RegisterSpec.make(i, Type.VOID);

        if (DEBUG) {
            ssaRegToRopReg.add(i);
        }
    }

    // Initial state for entry block
    startsForBlocks[ssaMeth.getEntryBlockIndex()] = initialRegMapping;
}
 

/**
 * Applies the optimization.
 */
private void run() {
    int regSz = ssaMeth.getRegCount();

    ArrayList<TypedConstant> constantList
            = getConstsSortedByCountUse();

    int toCollect = Math.min(constantList.size(), MAX_COLLECTED_CONSTANTS);

    SsaBasicBlock start = ssaMeth.getEntryBlock();

    // Constant to new register containing the constant
    HashMap<TypedConstant, RegisterSpec> newRegs
            = new HashMap<TypedConstant, RegisterSpec> (toCollect);

    for (int i = 0; i < toCollect; i++) {
        TypedConstant cst = constantList.get(i);
        RegisterSpec result
                = RegisterSpec.make(ssaMeth.makeNewSsaReg(), cst);

        Rop constRop = Rops.opConst(cst);

        if (constRop.getBranchingness() == Rop.BRANCH_NONE) {
            start.addInsnToHead(
                    new PlainCstInsn(Rops.opConst(cst),
                            SourcePosition.NO_INFO, result,
                            RegisterSpecList.EMPTY, cst));
        } else {
            // We need two new basic blocks along with the new insn
            SsaBasicBlock entryBlock = ssaMeth.getEntryBlock();
            SsaBasicBlock successorBlock
                    = entryBlock.getPrimarySuccessor();

            // Insert a block containing the const insn.
            SsaBasicBlock constBlock
                    = entryBlock.insertNewSuccessor(successorBlock);

            constBlock.replaceLastInsn(
                    new ThrowingCstInsn(constRop, SourcePosition.NO_INFO,
                            RegisterSpecList.EMPTY,
                            StdTypeList.EMPTY, cst));

            // Insert a block containing the move-result-pseudo insn.

            SsaBasicBlock resultBlock
                    = constBlock.insertNewSuccessor(successorBlock);
            PlainInsn insn
                = new PlainInsn(
                        Rops.opMoveResultPseudo(result.getTypeBearer()),
                        SourcePosition.NO_INFO,
                        result, RegisterSpecList.EMPTY);

            resultBlock.addInsnToHead(insn);
        }

        newRegs.put(cst, result);
    }

    updateConstUses(newRegs, regSz);
}
 

/**
 * Applies the optimization.
 */
private void run() {
    int regSz = ssaMeth.getRegCount();

    ArrayList<TypedConstant> constantList
            = getConstsSortedByCountUse();

    int toCollect = Math.min(constantList.size(), MAX_COLLECTED_CONSTANTS);

    SsaBasicBlock start = ssaMeth.getEntryBlock();

    // Constant to new register containing the constant
    HashMap<TypedConstant, RegisterSpec> newRegs
            = new HashMap<TypedConstant, RegisterSpec> (toCollect);

    for (int i = 0; i < toCollect; i++) {
        TypedConstant cst = constantList.get(i);
        RegisterSpec result
                = RegisterSpec.make(ssaMeth.makeNewSsaReg(), cst);

        Rop constRop = Rops.opConst(cst);

        if (constRop.getBranchingness() == Rop.BRANCH_NONE) {
            start.addInsnToHead(
                    new PlainCstInsn(Rops.opConst(cst),
                            SourcePosition.NO_INFO, result,
                            RegisterSpecList.EMPTY, cst));
        } else {
            // We need two new basic blocks along with the new insn
            SsaBasicBlock entryBlock = ssaMeth.getEntryBlock();
            SsaBasicBlock successorBlock
                    = entryBlock.getPrimarySuccessor();

            // Insert a block containing the const insn.
            SsaBasicBlock constBlock
                    = entryBlock.insertNewSuccessor(successorBlock);

            constBlock.replaceLastInsn(
                    new ThrowingCstInsn(constRop, SourcePosition.NO_INFO,
                            RegisterSpecList.EMPTY,
                            StdTypeList.EMPTY, cst));

            // Insert a block containing the move-result-pseudo insn.

            SsaBasicBlock resultBlock
                    = constBlock.insertNewSuccessor(successorBlock);
            PlainInsn insn
                = new PlainInsn(
                        Rops.opMoveResultPseudo(result.getTypeBearer()),
                        SourcePosition.NO_INFO,
                        result, RegisterSpecList.EMPTY);

            resultBlock.addInsnToHead(insn);
        }

        newRegs.put(cst, result);
    }

    updateConstUses(newRegs, regSz);
}
 

/**
 * 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;
}
 

/**
 * Constructs an instance of the renamer
 *
 * @param ssaMeth {@code non-null;} un-renamed SSA method that will
 * be renamed.
 */
public SsaRenamer(SsaMethod ssaMeth) {
    ropRegCount = ssaMeth.getRegCount();

    this.ssaMeth = ssaMeth;

    /*
     * Reserve the first N registers in the SSA register space for
     * "version 0" registers.
     */
    nextSsaReg = ropRegCount;
    threshold = 0;
    startsForBlocks = new RegisterSpec[ssaMeth.getBlocks().size()][];

    ssaRegToLocalItems = new ArrayList<LocalItem>();

    if (DEBUG) {
        ssaRegToRopReg = new IntList(ropRegCount);
    }

    /*
     * Appel 19.7
     *
     * Initialization:
     *   for each variable a        // register i
     *      Count[a] <- 0           // nextSsaReg, flattened
     *      Stack[a] <- 0           // versionStack
     *      push 0 onto Stack[a]
     *
     */

    // top entry for the version stack is version 0
    RegisterSpec[] initialRegMapping = new RegisterSpec[ropRegCount];
    for (int i = 0; i < ropRegCount; i++) {
        // everyone starts with a version 0 register
        initialRegMapping[i] = RegisterSpec.make(i, Type.VOID);

        if (DEBUG) {
            ssaRegToRopReg.add(i);
        }
    }

    // Initial state for entry block
    startsForBlocks[ssaMeth.getEntryBlockIndex()] = initialRegMapping;
}
 

/**
 * Replaces the use for a scalar replaceable array. Gets and puts become
 * move instructions, and array lengths and fills are handled. Can also
 * identify ArrayIndexOutOfBounds exceptions and throw them if detected.
 *
 * @param use {@code non-null;} move result instruction for array
 * @param prev {@code non-null;} instruction for instantiating new array
 * @param newRegs {@code non-null;} mapping of array indices to new
 * registers
 * @param deletedInsns {@code non-null;} set of instructions marked for
 * deletion
 */
private void replaceUse(SsaInsn use, SsaInsn prev,
                            ArrayList<RegisterSpec> newRegs,
                            HashSet<SsaInsn> deletedInsns) {
    int index;
    int length = newRegs.size();
    SsaInsn next;
    RegisterSpecList sources;
    RegisterSpec source, result;
    CstLiteralBits indexReg;

    switch (use.getOpcode().getOpcode()) {
        case RegOps.AGET:
            // Replace array gets with moves
            next = getMoveForInsn(use);
            sources = use.getSources();
            indexReg = ((CstLiteralBits) sources.get(1).getTypeBearer());
            index = indexReg.getIntBits();
            if (index < length) {
                source = newRegs.get(index);
                result = source.withReg(next.getResult().getReg());
                insertPlainInsnBefore(next, RegisterSpecList.make(source),
                                          result, RegOps.MOVE, null);
            } else {
                // Throw an exception if the index is out of bounds
                insertExceptionThrow(next, sources.get(1), deletedInsns);
                deletedInsns.add(next.getBlock().getInsns().get(2));
            }
            deletedInsns.add(next);
            break;
        case RegOps.APUT:
            // Replace array puts with moves
            sources = use.getSources();
            indexReg = ((CstLiteralBits) sources.get(2).getTypeBearer());
            index = indexReg.getIntBits();
            if (index < length) {
                source = sources.get(0);
                result = source.withReg(newRegs.get(index).getReg());
                insertPlainInsnBefore(use, RegisterSpecList.make(source),
                                          result, RegOps.MOVE, null);
                // Update the newReg entry to mark value as unknown now
                newRegs.set(index, result.withSimpleType());
            } else {
                // Throw an exception if the index is out of bounds
                insertExceptionThrow(use, sources.get(2), deletedInsns);
            }
            break;
        case RegOps.ARRAY_LENGTH:
            // Replace array lengths with const instructions
            TypeBearer lengthReg = prev.getSources().get(0).getTypeBearer();
            //CstInteger lengthReg = CstInteger.make(length);
            next = getMoveForInsn(use);
            insertPlainInsnBefore(next, RegisterSpecList.EMPTY,
                                      next.getResult(), RegOps.CONST,
                                      (Constant) lengthReg);
            deletedInsns.add(next);
            break;
        case RegOps.MARK_LOCAL:
            // Remove mark local instructions
            break;
        case RegOps.FILL_ARRAY_DATA:
            // Create const instructions for each fill value
            Insn ropUse = use.getOriginalRopInsn();
            FillArrayDataInsn fill = (FillArrayDataInsn) ropUse;
            ArrayList<Constant> constList = fill.getInitValues();
            for (int i = 0; i < length; i++) {
                RegisterSpec newFill =
                    RegisterSpec.make(newRegs.get(i).getReg(),
                                          (TypeBearer) constList.get(i));
                insertPlainInsnBefore(use, RegisterSpecList.EMPTY, newFill,
                                          RegOps.CONST, constList.get(i));
                // Update the newRegs to hold the new const value
                newRegs.set(i, newFill);
            }
            break;
        default:
    }
}
 

/**
 * Constructs an instance of the renamer
 *
 * @param ssaMeth {@code non-null;} un-renamed SSA method that will
 * be renamed.
 */
public SsaRenamer(SsaMethod ssaMeth) {
    ropRegCount = ssaMeth.getRegCount();

    this.ssaMeth = ssaMeth;

    /*
     * Reserve the first N registers in the SSA register space for
     * "version 0" registers.
     */
    nextSsaReg = ropRegCount;
    threshold = 0;
    startsForBlocks = new RegisterSpec[ssaMeth.getBlocks().size()][];

    ssaRegToLocalItems = new ArrayList<LocalItem>();

    if (DEBUG) {
        ssaRegToRopReg = new IntList(ropRegCount);
    }

    /*
     * Appel 19.7
     *
     * Initialization:
     *   for each variable a        // register i
     *      Count[a] <- 0           // nextSsaReg, flattened
     *      Stack[a] <- 0           // versionStack
     *      push 0 onto Stack[a]
     *
     */

    // top entry for the version stack is version 0
    RegisterSpec[] initialRegMapping = new RegisterSpec[ropRegCount];
    for (int i = 0; i < ropRegCount; i++) {
        // everyone starts with a version 0 register
        initialRegMapping[i] = RegisterSpec.make(i, Type.VOID);

        if (DEBUG) {
            ssaRegToRopReg.add(i);
        }
    }

    // Initial state for entry block
    startsForBlocks[ssaMeth.getEntryBlockIndex()] = initialRegMapping;
}