com.android.dx.rop.cst.TypedConstant Java Examples

/**
 * Constructs an instance.
 *
 * @param constantValue {@code non-null;} the constant value, which must
 * be an instance of one of: {@code CstString},
 * {@code CstInteger}, {@code CstLong},
 * {@code CstFloat}, or {@code CstDouble}
 */
public AttConstantValue(TypedConstant constantValue) {
    super(ATTRIBUTE_NAME);

    if (!((constantValue instanceof CstString) ||
           (constantValue instanceof CstInteger) ||
           (constantValue instanceof CstLong) ||
           (constantValue instanceof CstFloat) ||
           (constantValue instanceof CstDouble))) {
        if (constantValue == null) {
            throw new NullPointerException("constantValue == null");
        }
        throw new IllegalArgumentException("bad type for constantValue");
    }

    this.constantValue = constantValue;
}
 

/**
 * 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);
    }
}
 

/**
 * Parses a {@code ConstantValue} attribute.
 */
private Attribute constantValue(DirectClassFile cf, int offset, int length,
        ParseObserver observer) {
    if (length != 2) {
        return throwBadLength(2);
    }

    ByteArray bytes = cf.getBytes();
    ConstantPool pool = cf.getConstantPool();
    int idx = bytes.getUnsignedShort(offset);
    TypedConstant cst = (TypedConstant) pool.get(idx);
    Attribute result = new AttConstantValue(cst);

    if (observer != null) {
        observer.parsed(bytes, offset, 2, "value: " + cst);
    }

    return result;
}
 

/**
 * Parses a {@code ConstantValue} attribute.
 */
private Attribute constantValue(DirectClassFile cf, int offset, int length,
        ParseObserver observer) {
    if (length != 2) {
        return throwBadLength(2);
    }

    ByteArray bytes = cf.getBytes();
    ConstantPool pool = cf.getConstantPool();
    int idx = bytes.getUnsignedShort(offset);
    TypedConstant cst = (TypedConstant) pool.get(idx);
    Attribute result = new AttConstantValue(cst);

    if (observer != null) {
        observer.parsed(bytes, offset, 2, "value: " + cst);
    }

    return result;
}
 

/**
 * Constructs an instance.
 *
 * @param constantValue {@code non-null;} the constant value, which must
 * be an instance of one of: {@code CstString},
 * {@code CstInteger}, {@code CstLong},
 * {@code CstFloat}, or {@code CstDouble}
 */
public AttConstantValue(TypedConstant constantValue) {
    super(ATTRIBUTE_NAME);

    if (!((constantValue instanceof CstString) ||
           (constantValue instanceof CstInteger) ||
           (constantValue instanceof CstLong) ||
           (constantValue instanceof CstFloat) ||
           (constantValue instanceof CstDouble))) {
        if (constantValue == null) {
            throw new NullPointerException("constantValue == null");
        }
        throw new IllegalArgumentException("bad type for constantValue");
    }

    this.constantValue = constantValue;
}
 

/**
 * 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);
    }
}
 

/**
 * 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);
    }
}
 

/**
 * Constructs an instance.
 *
 * @param constantValue {@code non-null;} the constant value, which must
 * be an instance of one of: {@code CstString},
 * {@code CstInteger}, {@code CstLong},
 * {@code CstFloat}, or {@code CstDouble}
 */
public AttConstantValue(TypedConstant constantValue) {
    super(ATTRIBUTE_NAME);

    if (!((constantValue instanceof CstString) ||
           (constantValue instanceof CstInteger) ||
           (constantValue instanceof CstLong) ||
           (constantValue instanceof CstFloat) ||
           (constantValue instanceof CstDouble))) {
        if (constantValue == null) {
            throw new NullPointerException("constantValue == null");
        }
        throw new IllegalArgumentException("bad type for constantValue");
    }

    this.constantValue = constantValue;
}
 

/**
 * Parses a {@code ConstantValue} attribute.
 */
private Attribute constantValue(DirectClassFile cf, int offset, int length,
        ParseObserver observer) {
    if (length != 2) {
        return throwBadLength(2);
    }

    ByteArray bytes = cf.getBytes();
    ConstantPool pool = cf.getConstantPool();
    int idx = bytes.getUnsignedShort(offset);
    TypedConstant cst = (TypedConstant) pool.get(idx);
    Attribute result = new AttConstantValue(cst);

    if (observer != null) {
        observer.parsed(bytes, offset, 2, "value: " + cst);
    }

    return result;
}
 

/**
 * Parses a {@code ConstantValue} attribute.
 */
private Attribute constantValue(DirectClassFile cf, int offset, int length,
        ParseObserver observer) {
    if (length != 2) {
        return throwBadLength(2);
    }

    ByteArray bytes = cf.getBytes();
    ConstantPool pool = cf.getConstantPool();
    int idx = bytes.getUnsignedShort(offset);
    TypedConstant cst = (TypedConstant) pool.get(idx);
    Attribute result = new AttConstantValue(cst);

    if (observer != null) {
        observer.parsed(bytes, offset, 2, "value: " + cst);
    }

    return result;
}
 

/**
 * Constructs an instance.
 *
 * @param constantValue {@code non-null;} the constant value, which must
 * be an instance of one of: {@code CstString},
 * {@code CstInteger}, {@code CstLong},
 * {@code CstFloat}, or {@code CstDouble}
 */
public AttConstantValue(TypedConstant constantValue) {
    super(ATTRIBUTE_NAME);

    if (!((constantValue instanceof CstString) ||
           (constantValue instanceof CstInteger) ||
           (constantValue instanceof CstLong) ||
           (constantValue instanceof CstFloat) ||
           (constantValue instanceof CstDouble))) {
        if (constantValue == null) {
            throw new NullPointerException("constantValue == null");
        }
        throw new IllegalArgumentException("bad type for constantValue");
    }

    this.constantValue = constantValue;
}
 

/**
 * Returns a rop constant for the specified value.
 *
 * @param value null, a boxed primitive, String, Class, or TypeId.
 */
static TypedConstant getConstant(Object value) {
    if (value == null) {
        return CstKnownNull.THE_ONE;
    } else if (value instanceof Boolean) {
        return CstBoolean.make((Boolean) value);
    } else if (value instanceof Byte) {
        return CstByte.make((Byte) value);
    } else if (value instanceof Character) {
        return CstChar.make((Character) value);
    } else if (value instanceof Double) {
        return CstDouble.make(Double.doubleToLongBits((Double) value));
    } else if (value instanceof Float) {
        return CstFloat.make(Float.floatToIntBits((Float) value));
    } else if (value instanceof Integer) {
        return CstInteger.make((Integer) value);
    } else if (value instanceof Long) {
        return CstLong.make((Long) value);
    } else if (value instanceof Short) {
        return CstShort.make((Short) value);
    } else if (value instanceof String) {
        return new CstString((String) value);
    } else if (value instanceof Class) {
        return new CstType(TypeId.get((Class<?>) value).ropType);
    } else if (value instanceof TypeId) {
        return new CstType(((TypeId) value).ropType);
    } else {
        throw new UnsupportedOperationException("Not a constant: " + value);
    }
}
 

/**
 * Helper for {@link #processFields}, which translates constants into
 * more specific types if necessary.
 *
 * @param constant {@code non-null;} the constant in question
 * @param type {@code non-null;} the desired type
 */
private static TypedConstant coerceConstant(TypedConstant constant,
        Type type) {
    Type constantType = constant.getType();

    if (constantType.equals(type)) {
        return constant;
    }

    switch (type.getBasicType()) {
        case Type.BT_BOOLEAN: {
            return CstBoolean.make(((CstInteger) constant).getValue());
        }
        case Type.BT_BYTE: {
            return CstByte.make(((CstInteger) constant).getValue());
        }
        case Type.BT_CHAR: {
            return CstChar.make(((CstInteger) constant).getValue());
        }
        case Type.BT_SHORT: {
            return CstShort.make(((CstInteger) constant).getValue());
        }
        default: {
            throw new UnsupportedOperationException("can't coerce " +
                    constant + " to " + type);
        }
    }
}
 

/**
 * Helper for {@link #processFields}, which translates constants into
 * more specific types if necessary.
 *
 * @param constant {@code non-null;} the constant in question
 * @param type {@code non-null;} the desired type
 */
private static TypedConstant coerceConstant(TypedConstant constant,
        Type type) {
    Type constantType = constant.getType();

    if (constantType.equals(type)) {
        return constant;
    }

    switch (type.getBasicType()) {
        case Type.BT_BOOLEAN: {
            return CstBoolean.make(((CstInteger) constant).getValue());
        }
        case Type.BT_BYTE: {
            return CstByte.make(((CstInteger) constant).getValue());
        }
        case Type.BT_CHAR: {
            return CstChar.make(((CstInteger) constant).getValue());
        }
        case Type.BT_SHORT: {
            return CstShort.make(((CstInteger) constant).getValue());
        }
        default: {
            throw new UnsupportedOperationException("can't coerce " +
                    constant + " to " + type);
        }
    }
}
 

/** {@inheritDoc} */
   @Override
public TypedConstant getConstantValue() {
       AttributeList attribs = getAttributes();
       AttConstantValue cval = (AttConstantValue)
           attribs.findFirst(AttConstantValue.ATTRIBUTE_NAME);

       if (cval == null) {
           return null;
       }

       return cval.getConstantValue();
   }
 

/**
 * Returns a rop constant for the specified value.
 *
 * @param value null, a boxed primitive, String, Class, or TypeId.
 */
static TypedConstant getConstant(Object value) {
    if (value == null) {
        return CstKnownNull.THE_ONE;
    } else if (value instanceof Boolean) {
        return CstBoolean.make((Boolean) value);
    } else if (value instanceof Byte) {
        return CstByte.make((Byte) value);
    } else if (value instanceof Character) {
        return CstChar.make((Character) value);
    } else if (value instanceof Double) {
        return CstDouble.make(Double.doubleToLongBits((Double) value));
    } else if (value instanceof Float) {
        return CstFloat.make(Float.floatToIntBits((Float) value));
    } else if (value instanceof Integer) {
        return CstInteger.make((Integer) value);
    } else if (value instanceof Long) {
        return CstLong.make((Long) value);
    } else if (value instanceof Short) {
        return CstShort.make((Short) value);
    } else if (value instanceof String) {
        return new CstString((String) value);
    } else if (value instanceof Class) {
        return new CstType(TypeId.get((Class<?>) value).ropType);
    } else if (value instanceof TypeId) {
        return new CstType(((TypeId) value).ropType);
    } else {
        throw new UnsupportedOperationException("Not a constant: " + value);
    }
}
 

/**
 * Helper for {@link #processFields}, which translates constants into
 * more specific types if necessary.
 *
 * @param constant {@code non-null;} the constant in question
 * @param type {@code non-null;} the desired type
 */
private static TypedConstant coerceConstant(TypedConstant constant,
        Type type) {
    Type constantType = constant.getType();

    if (constantType.equals(type)) {
        return constant;
    }

    switch (type.getBasicType()) {
        case Type.BT_BOOLEAN: {
            return CstBoolean.make(((CstInteger) constant).getValue());
        }
        case Type.BT_BYTE: {
            return CstByte.make(((CstInteger) constant).getValue());
        }
        case Type.BT_CHAR: {
            return CstChar.make(((CstInteger) constant).getValue());
        }
        case Type.BT_SHORT: {
            return CstShort.make(((CstInteger) constant).getValue());
        }
        default: {
            throw new UnsupportedOperationException("can't coerce " +
                    constant + " to " + type);
        }
    }
}
 

/** {@inheritDoc} */
public TypedConstant getConstantValue() {
    AttributeList attribs = getAttributes();
    AttConstantValue cval = (AttConstantValue)
        attribs.findFirst(AttConstantValue.ATTRIBUTE_NAME);

    if (cval == null) {
        return null;
    }

    return cval.getConstantValue();
}
 

/** {@inheritDoc} */
@Override
public TypedConstant getConstantValue() {
    AttributeList attribs = getAttributes();
    AttConstantValue cval = (AttConstantValue)
        attribs.findFirst(AttConstantValue.ATTRIBUTE_NAME);

    if (cval == null) {
        return null;
    }

    return cval.getConstantValue();
}
 

/** {@inheritDoc} */
@Override
public TypedConstant getConstantValue() {
    AttributeList attribs = getAttributes();
    AttConstantValue cval = (AttConstantValue)
        attribs.findFirst(AttConstantValue.ATTRIBUTE_NAME);

    if (cval == null) {
        return null;
    }

    return cval.getConstantValue();
}
 

/**
 * Helper for {@link #processFields}, which translates constants into
 * more specific types if necessary.
 *
 * @param constant {@code non-null;} the constant in question
 * @param type {@code non-null;} the desired type
 */
private static TypedConstant coerceConstant(TypedConstant constant,
        Type type) {
    Type constantType = constant.getType();

    if (constantType.equals(type)) {
        return constant;
    }

    switch (type.getBasicType()) {
        case Type.BT_BOOLEAN: {
            return CstBoolean.make(((CstInteger) constant).getValue());
        }
        case Type.BT_BYTE: {
            return CstByte.make(((CstInteger) constant).getValue());
        }
        case Type.BT_CHAR: {
            return CstChar.make(((CstInteger) constant).getValue());
        }
        case Type.BT_SHORT: {
            return CstShort.make(((CstInteger) constant).getValue());
        }
        default: {
            throw new UnsupportedOperationException("can't coerce " +
                    constant + " to " + type);
        }
    }
}
 

/**
 * Updates all uses of various consts to use the values in the newly
 * assigned registers.
 *
 * @param newRegs {@code non-null;} mapping between constant and new reg
 * @param origRegCount {@code >=0;} original SSA reg count, not including
 * newly added constant regs
 */
private void updateConstUses(HashMap<TypedConstant, RegisterSpec> newRegs,
        int origRegCount) {

    /*
     * set of constants associated with a local variable; used
     * only if COLLECT_ONE_LOCAL is true.
     */
    final HashSet<TypedConstant> usedByLocal
            = new HashSet<TypedConstant>();

    final ArrayList<SsaInsn>[] useList = ssaMeth.getUseListCopy();

    for (int i = 0; i < origRegCount; i++) {
        SsaInsn insn = ssaMeth.getDefinitionForRegister(i);

        if (insn == null) {
            continue;
        }

        final RegisterSpec origReg = insn.getResult();
        TypeBearer typeBearer = insn.getResult().getTypeBearer();

        if (!typeBearer.isConstant()) continue;

        TypedConstant cst = (TypedConstant) typeBearer;
        final RegisterSpec newReg = newRegs.get(cst);

        if (newReg == null) {
            continue;
        }

        if (ssaMeth.isRegALocal(origReg)) {
            if (!COLLECT_ONE_LOCAL) {
                continue;
            } else {
                /*
                 * TODO: If the same local gets the same cst
                 * multiple times, it would be nice to reuse the
                 * register.
                 */
                if (usedByLocal.contains(cst)) {
                    continue;
                } else {
                    usedByLocal.add(cst);
                    fixLocalAssignment(origReg, newRegs.get(cst));
                }
            }
        }

        // maps an original const register to the new collected register
        RegisterMapper mapper = new RegisterMapper() {
            @Override
            public int getNewRegisterCount() {
                return ssaMeth.getRegCount();
            }

            @Override
            public RegisterSpec map(RegisterSpec registerSpec) {
                if (registerSpec.getReg() == origReg.getReg()) {
                    return newReg.withLocalItem(
                            registerSpec.getLocalItem());
                }

                return registerSpec;
            }
        };

        for (SsaInsn use : useList[origReg.getReg()]) {
            if (use.canThrow()
                    && use.getBlock().getSuccessors().cardinality() > 1) {
                continue;
            }
            use.mapSourceRegisters(mapper);
        }
    }
}
 

/**
 * Updates all uses of various consts to use the values in the newly
 * assigned registers.
 *
 * @param newRegs {@code non-null;} mapping between constant and new reg
 * @param origRegCount {@code >=0;} original SSA reg count, not including
 * newly added constant regs
 */
private void updateConstUses(HashMap<TypedConstant, RegisterSpec> newRegs,
        int origRegCount) {

    /*
     * set of constants associated with a local variable; used
     * only if COLLECT_ONE_LOCAL is true.
     */
    final HashSet<TypedConstant> usedByLocal
            = new HashSet<TypedConstant>();

    final ArrayList<SsaInsn>[] useList = ssaMeth.getUseListCopy();

    for (int i = 0; i < origRegCount; i++) {
        SsaInsn insn = ssaMeth.getDefinitionForRegister(i);

        if (insn == null) {
            continue;
        }

        final RegisterSpec origReg = insn.getResult();
        TypeBearer typeBearer = insn.getResult().getTypeBearer();

        if (!typeBearer.isConstant()) continue;

        TypedConstant cst = (TypedConstant) typeBearer;
        final RegisterSpec newReg = newRegs.get(cst);

        if (newReg == null) {
            continue;
        }

        if (ssaMeth.isRegALocal(origReg)) {
            if (!COLLECT_ONE_LOCAL) {
                continue;
            } else {
                /*
                 * TODO: If the same local gets the same cst
                 * multiple times, it would be nice to reuse the
                 * register.
                 */
                if (usedByLocal.contains(cst)) {
                    continue;
                } else {
                    usedByLocal.add(cst);
                    fixLocalAssignment(origReg, newRegs.get(cst));
                }
            }
        }

        // maps an original const register to the new collected register
        RegisterMapper mapper = new RegisterMapper() {
            @Override
            public int getNewRegisterCount() {
                return ssaMeth.getRegCount();
            }

            @Override
            public RegisterSpec map(RegisterSpec registerSpec) {
                if (registerSpec.getReg() == origReg.getReg()) {
                    return newReg.withLocalItem(
                            registerSpec.getLocalItem());
                }

                return registerSpec;
            }
        };

        for (SsaInsn use : useList[origReg.getReg()]) {
            if (use.canThrow()
                    && use.getBlock().getSuccessors().cardinality() > 1) {
                continue;
            }
            use.mapSourceRegisters(mapper);
        }
    }
}
 

/**
 * 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);
}
 

/**
 * Replaces TypeBearers in source register specs with constant type
 * bearers if possible. These are then referenced in later optimization
 * steps.
 */
private void replaceConstants() {
    for (int reg = 0; reg < regCount; reg++) {
        if (latticeValues[reg] != CONSTANT) {
            continue;
        }
        if (!(latticeConstants[reg] instanceof TypedConstant)) {
            // We can't do much with these
            continue;
        }

        SsaInsn defn = ssaMeth.getDefinitionForRegister(reg);
        TypeBearer typeBearer = defn.getResult().getTypeBearer();

        if (typeBearer.isConstant()) {
            /*
             * The definition was a constant already.
             * The uses should be as well.
             */
            continue;
        }

        // Update the destination RegisterSpec with the constant value
        RegisterSpec dest = defn.getResult();
        RegisterSpec newDest
                = dest.withType((TypedConstant)latticeConstants[reg]);
        defn.setResult(newDest);

        /*
         * Update the sources RegisterSpec's of all non-move uses.
         * These will be used in later steps.
         */
        for (SsaInsn insn : ssaMeth.getUseListForRegister(reg)) {
            if (insn.isPhiOrMove()) {
                continue;
            }

            NormalSsaInsn nInsn = (NormalSsaInsn) insn;
            RegisterSpecList sources = insn.getSources();

            int index = sources.indexOfRegister(reg);

            RegisterSpec spec = sources.get(index);
            RegisterSpec newSpec
                    = spec.withType((TypedConstant)latticeConstants[reg]);

            nInsn.changeOneSource(index, newSpec);
        }
    }
}
 

/**
 * Replaces TypeBearers in source register specs with constant type
 * bearers if possible. These are then referenced in later optimization
 * steps.
 */
private void replaceConstants() {
    for (int reg = 0; reg < regCount; reg++) {
        if (latticeValues[reg] != CONSTANT) {
            continue;
        }
        if (!(latticeConstants[reg] instanceof TypedConstant)) {
            // We can't do much with these
            continue;
        }

        SsaInsn defn = ssaMeth.getDefinitionForRegister(reg);
        TypeBearer typeBearer = defn.getResult().getTypeBearer();

        if (typeBearer.isConstant()) {
            /*
             * The definition was a constant already.
             * The uses should be as well.
             */
            continue;
        }

        // Update the destination RegisterSpec with the constant value
        RegisterSpec dest = defn.getResult();
        RegisterSpec newDest
                = dest.withType((TypedConstant)latticeConstants[reg]);
        defn.setResult(newDest);

        /*
         * Update the sources RegisterSpec's of all non-move uses.
         * These will be used in later steps.
         */
        for (SsaInsn insn : ssaMeth.getUseListForRegister(reg)) {
            if (insn.isPhiOrMove()) {
                continue;
            }

            NormalSsaInsn nInsn = (NormalSsaInsn) insn;
            RegisterSpecList sources = insn.getSources();

            int index = sources.indexOfRegister(reg);

            RegisterSpec spec = sources.get(index);
            RegisterSpec newSpec
                    = spec.withType((TypedConstant)latticeConstants[reg]);

            nInsn.changeOneSource(index, newSpec);
        }
    }
}
 

/**
 * 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);
}
 

/**
 * Updates all uses of various consts to use the values in the newly
 * assigned registers.
 *
 * @param newRegs {@code non-null;} mapping between constant and new reg
 * @param origRegCount {@code >=0;} original SSA reg count, not including
 * newly added constant regs
 */
private void updateConstUses(HashMap<TypedConstant, RegisterSpec> newRegs,
        int origRegCount) {

    /*
     * set of constants associated with a local variable; used
     * only if COLLECT_ONE_LOCAL is true.
     */
    final HashSet<TypedConstant> usedByLocal
            = new HashSet<TypedConstant>();

    final ArrayList<SsaInsn>[] useList = ssaMeth.getUseListCopy();

    for (int i = 0; i < origRegCount; i++) {
        SsaInsn insn = ssaMeth.getDefinitionForRegister(i);

        if (insn == null) {
            continue;
        }

        final RegisterSpec origReg = insn.getResult();
        TypeBearer typeBearer = insn.getResult().getTypeBearer();

        if (!typeBearer.isConstant()) continue;

        TypedConstant cst = (TypedConstant) typeBearer;
        final RegisterSpec newReg = newRegs.get(cst);

        if (newReg == null) {
            continue;
        }

        if (ssaMeth.isRegALocal(origReg)) {
            if (!COLLECT_ONE_LOCAL) {
                continue;
            } else {
                /*
                 * TODO: If the same local gets the same cst
                 * multiple times, it would be nice to reuse the
                 * register.
                 */
                if (usedByLocal.contains(cst)) {
                    continue;
                } else {
                    usedByLocal.add(cst);
                    fixLocalAssignment(origReg, newRegs.get(cst));
                }
            }
        }

        // maps an original const register to the new collected register
        RegisterMapper mapper = new RegisterMapper() {
            @Override
            public int getNewRegisterCount() {
                return ssaMeth.getRegCount();
            }

            @Override
            public RegisterSpec map(RegisterSpec registerSpec) {
                if (registerSpec.getReg() == origReg.getReg()) {
                    return newReg.withLocalItem(
                            registerSpec.getLocalItem());
                }

                return registerSpec;
            }
        };

        for (SsaInsn use : useList[origReg.getReg()]) {
            if (use.canThrow()
                    && use.getBlock().getSuccessors().cardinality() > 1) {
                continue;
            }
            use.mapSourceRegisters(mapper);
        }
    }
}
 

/**
 * Updates all uses of various consts to use the values in the newly
 * assigned registers.
 *
 * @param newRegs {@code non-null;} mapping between constant and new reg
 * @param origRegCount {@code >=0;} original SSA reg count, not including
 * newly added constant regs
 */
private void updateConstUses(HashMap<TypedConstant, RegisterSpec> newRegs,
        int origRegCount) {

    /*
     * set of constants associated with a local variable; used
     * only if COLLECT_ONE_LOCAL is true.
     */
    final HashSet<TypedConstant> usedByLocal
            = new HashSet<TypedConstant>();

    final ArrayList<SsaInsn>[] useList = ssaMeth.getUseListCopy();

    for (int i = 0; i < origRegCount; i++) {
        SsaInsn insn = ssaMeth.getDefinitionForRegister(i);

        if (insn == null) {
            continue;
        }

        final RegisterSpec origReg = insn.getResult();
        TypeBearer typeBearer = insn.getResult().getTypeBearer();

        if (!typeBearer.isConstant()) continue;

        TypedConstant cst = (TypedConstant) typeBearer;
        final RegisterSpec newReg = newRegs.get(cst);

        if (newReg == null) {
            continue;
        }

        if (ssaMeth.isRegALocal(origReg)) {
            if (!COLLECT_ONE_LOCAL) {
                continue;
            } else {
                /*
                 * TODO: If the same local gets the same cst
                 * multiple times, it would be nice to reuse the
                 * register.
                 */
                if (usedByLocal.contains(cst)) {
                    continue;
                } else {
                    usedByLocal.add(cst);
                    fixLocalAssignment(origReg, newRegs.get(cst));
                }
            }
        }

        // maps an original const register to the new collected register
        RegisterMapper mapper = new RegisterMapper() {
            @Override
            public int getNewRegisterCount() {
                return ssaMeth.getRegCount();
            }

            @Override
            public RegisterSpec map(RegisterSpec registerSpec) {
                if (registerSpec.getReg() == origReg.getReg()) {
                    return newReg.withLocalItem(
                            registerSpec.getLocalItem());
                }

                return registerSpec;
            }
        };

        for (SsaInsn use : useList[origReg.getReg()]) {
            if (use.canThrow()
                    && use.getBlock().getSuccessors().cardinality() > 1) {
                continue;
            }
            use.mapSourceRegisters(mapper);
        }
    }
}