com.android.dx.ssa.SsaInsn Java Examples

/**
 * "v is live-out at n."
 */
private void liveOutAtBlock() {
    if (! visitedBlocks.get(blockN.getIndex())) {
        visitedBlocks.set(blockN.getIndex());

        blockN.addLiveOut(regV);

        ArrayList<SsaInsn> insns;

        insns = blockN.getInsns();

        // Live out at last statement in blockN
        statementIndex = insns.size() - 1;
        nextFunction = NextFunction.LIVE_OUT_AT_STATEMENT;
    }
}
 

/**
 * "v is live-out at n."
 */
private void liveOutAtBlock() {
    if (! visitedBlocks.get(blockN.getIndex())) {
        visitedBlocks.set(blockN.getIndex());

        blockN.addLiveOut(regV);

        ArrayList<SsaInsn> insns;

        insns = blockN.getInsns();

        // Live out at last statement in blockN
        statementIndex = insns.size() - 1;
        nextFunction = NextFunction.LIVE_OUT_AT_STATEMENT;
    }
}
 

/**
 * Ensures that all the phi result registers for all the phis in the
 * same basic block interfere with each other. This is needed since
 * the dead code remover has allowed through "dead-end phis" whose
 * results are not used except as local assignments. Without this step,
 * a the result of a dead-end phi might be assigned the same register
 * as the result of another phi, and the phi removal move scheduler may
 * generate moves that over-write the live result.
 *
 * @param ssaMeth {@code non-null;} method to pricess
 * @param interference {@code non-null;} interference graph
 */
private static void coInterferePhis(SsaMethod ssaMeth,
        InterferenceGraph interference) {
    for (SsaBasicBlock b : ssaMeth.getBlocks()) {
        List<SsaInsn> phis = b.getPhiInsns();

        int szPhis = phis.size();

        for (int i = 0; i < szPhis; i++) {
            for (int j = 0; j < szPhis; j++) {
                if (i == j) {
                    continue;
                }

                interference.add(phis.get(i).getResult().getReg(),
                    phis.get(j).getResult().getReg());
            }
        }
    }
}
 

/**
 * Gets the parameter index for SSA registers that are method parameters.
 * {@code -1} is returned for non-parameter registers.
 *
 * @param ssaReg {@code >=0;} SSA register to look up
 * @return parameter index or {@code -1} if not a parameter
 */
private int getParameterIndexForReg(int ssaReg) {
    SsaInsn defInsn = ssaMeth.getDefinitionForRegister(ssaReg);
    if (defInsn == null) {
        return -1;
    }

    Rop opcode = defInsn.getOpcode();

    // opcode == null for phi insns.
    if (opcode != null && opcode.getOpcode() == RegOps.MOVE_PARAM) {
        CstInsn origInsn = (CstInsn) defInsn.getOriginalRopInsn();
        return  ((CstInteger) origInsn.getConstant()).getValue();
    }

    return -1;
}
 

/**
 * Removes all blocks containing only GOTOs from the control flow.
 * Although much of this work will be done later when converting
 * from rop to dex, not all simplification cases can be handled
 * there. Furthermore, any no-op block between the exit block and
 * blocks containing the real return or throw statements must be
 * removed.
 */
private void removeEmptyGotos() {
    final ArrayList<SsaBasicBlock> blocks = ssaMeth.getBlocks();

    ssaMeth.forEachBlockDepthFirst(false, new SsaBasicBlock.Visitor() {
        @Override
        public void visitBlock(SsaBasicBlock b, SsaBasicBlock parent) {
            ArrayList<SsaInsn> insns = b.getInsns();

            if ((insns.size() == 1)
                    && (insns.get(0).getOpcode() == Rops.GOTO)) {
                BitSet preds = (BitSet) b.getPredecessors().clone();

                for (int i = preds.nextSetBit(0); i >= 0;
                        i = preds.nextSetBit(i + 1)) {
                    SsaBasicBlock pb = blocks.get(i);
                    pb.replaceSuccessor(b.getIndex(),
                            b.getPrimarySuccessorIndex());
                }
            }
        }
    });
}
 

/**
  * Removes all blocks containing only GOTOs from the control flow.
  * Although much of this work will be done later when converting
  * from rop to dex, not all simplification cases can be handled
  * there. Furthermore, any no-op block between the exit block and
  * blocks containing the real return or throw statements must be
  * removed.
  */
 private void removeEmptyGotos() {
     final ArrayList<SsaBasicBlock> blocks = ssaMeth.getBlocks();

     ssaMeth.forEachBlockDepthFirst(false, new SsaBasicBlock.Visitor() {
         @Override
public void visitBlock(SsaBasicBlock b, SsaBasicBlock parent) {
             ArrayList<SsaInsn> insns = b.getInsns();

             if ((insns.size() == 1)
                     && (insns.get(0).getOpcode() == Rops.GOTO)) {
                 BitSet preds = (BitSet) b.getPredecessors().clone();

                 for (int i = preds.nextSetBit(0); i >= 0;
                         i = preds.nextSetBit(i + 1)) {
                     SsaBasicBlock pb = blocks.get(i);
                     pb.replaceSuccessor(b.getIndex(),
                             b.getPrimarySuccessorIndex());
                 }
             }
         }
     });
 }
 

/**
 * Gets the parameter index for SSA registers that are method parameters.
 * {@code -1} is returned for non-parameter registers.
 *
 * @param ssaReg {@code >=0;} SSA register to look up
 * @return parameter index or {@code -1} if not a parameter
 */
private int getParameterIndexForReg(int ssaReg) {
    SsaInsn defInsn = ssaMeth.getDefinitionForRegister(ssaReg);
    if (defInsn == null) {
        return -1;
    }

    Rop opcode = defInsn.getOpcode();

    // opcode == null for phi insns.
    if (opcode != null && opcode.getOpcode() == RegOps.MOVE_PARAM) {
        CstInsn origInsn = (CstInsn) defInsn.getOriginalRopInsn();
        return  ((CstInteger) origInsn.getConstant()).getValue();
    }

    return -1;
}
 

/**
 * Ensures that all the phi result registers for all the phis in the
 * same basic block interfere with each other, and also that a phi's source
 * registers interfere with the result registers from other phis. This is needed since
 * the dead code remover has allowed through "dead-end phis" whose
 * results are not used except as local assignments. Without this step,
 * a the result of a dead-end phi might be assigned the same register
 * as the result of another phi, and the phi removal move scheduler may
 * generate moves that over-write the live result.
 *
 * @param ssaMeth {@code non-null;} method to process
 * @param interference {@code non-null;} interference graph
 */
private static void coInterferePhis(SsaMethod ssaMeth,
        InterferenceGraph interference) {
    for (SsaBasicBlock b : ssaMeth.getBlocks()) {
        List<SsaInsn> phis = b.getPhiInsns();

        int szPhis = phis.size();

        for (int i = 0; i < szPhis; i++) {
            for (int j = 0; j < szPhis; j++) {
                if (i == j) {
                    continue;
                }

                SsaInsn first = phis.get(i);
                SsaInsn second = phis.get(j);
                coInterferePhiRegisters(interference, first.getResult(), second.getSources());
                coInterferePhiRegisters(interference, second.getResult(), first.getSources());
                interference.add(first.getResult().getReg(), second.getResult().getReg());
            }
        }
    }
}
 

/**
 * "v is live-out at n."
 */
private void liveOutAtBlock() {
    if (! visitedBlocks.get(blockN.getIndex())) {
        visitedBlocks.set(blockN.getIndex());

        blockN.addLiveOut(regV);

        ArrayList<SsaInsn> insns;

        insns = blockN.getInsns();

        // Live out at last statement in blockN
        statementIndex = insns.size() - 1;
        nextFunction = NextFunction.LIVE_OUT_AT_STATEMENT;
    }
}
 

/**
 * Ensures that all the phi result registers for all the phis in the
 * same basic block interfere with each other. This is needed since
 * the dead code remover has allowed through "dead-end phis" whose
 * results are not used except as local assignments. Without this step,
 * a the result of a dead-end phi might be assigned the same register
 * as the result of another phi, and the phi removal move scheduler may
 * generate moves that over-write the live result.
 *
 * @param ssaMeth {@code non-null;} method to pricess
 * @param interference {@code non-null;} interference graph
 */
private static void coInterferePhis(SsaMethod ssaMeth,
        InterferenceGraph interference) {
    for (SsaBasicBlock b : ssaMeth.getBlocks()) {
        List<SsaInsn> phis = b.getPhiInsns();

        int szPhis = phis.size();

        for (int i = 0; i < szPhis; i++) {
            for (int j = 0; j < szPhis; j++) {
                if (i == j) {
                    continue;
                }

                interference.add(phis.get(i).getResult().getReg(),
                    phis.get(j).getResult().getReg());
            }
        }
    }
}
 

/**
 * Gets the parameter index for SSA registers that are method parameters.
 * {@code -1} is returned for non-parameter registers.
 *
 * @param ssaReg {@code >=0;} SSA register to look up
 * @return parameter index or {@code -1} if not a parameter
 */
private int getParameterIndexForReg(int ssaReg) {
    SsaInsn defInsn = ssaMeth.getDefinitionForRegister(ssaReg);
    if (defInsn == null) {
        return -1;
    }

    Rop opcode = defInsn.getOpcode();

    // opcode == null for phi insns.
    if (opcode != null && opcode.getOpcode() == RegOps.MOVE_PARAM) {
        CstInsn origInsn = (CstInsn) defInsn.getOriginalRopInsn();
        return  ((CstInteger) origInsn.getConstant()).getValue();
    }

    return -1;
}
 

/**
 * "v is live-out at n."
 */
private void liveOutAtBlock() {
    if (! visitedBlocks.get(blockN.getIndex())) {
        visitedBlocks.set(blockN.getIndex());

        blockN.addLiveOut(regV);

        ArrayList<SsaInsn> insns;

        insns = blockN.getInsns();

        // Live out at last statement in blockN
        statementIndex = insns.size() - 1;
        nextFunction = NextFunction.LIVE_OUT_AT_STATEMENT;
    }
}
 

/**
 * Ensures that all the phi result registers for all the phis in the
 * same basic block interfere with each other, and also that a phi's source
 * registers interfere with the result registers from other phis. This is needed since
 * the dead code remover has allowed through "dead-end phis" whose
 * results are not used except as local assignments. Without this step,
 * a the result of a dead-end phi might be assigned the same register
 * as the result of another phi, and the phi removal move scheduler may
 * generate moves that over-write the live result.
 *
 * @param ssaMeth {@code non-null;} method to process
 * @param interference {@code non-null;} interference graph
 */
private static void coInterferePhis(SsaMethod ssaMeth,
        InterferenceGraph interference) {
    for (SsaBasicBlock b : ssaMeth.getBlocks()) {
        List<SsaInsn> phis = b.getPhiInsns();

        int szPhis = phis.size();

        for (int i = 0; i < szPhis; i++) {
            for (int j = 0; j < szPhis; j++) {
                if (i == j) {
                    continue;
                }

                SsaInsn first = phis.get(i);
                SsaInsn second = phis.get(j);
                coInterferePhiRegisters(interference, first.getResult(), second.getSources());
                coInterferePhiRegisters(interference, second.getResult(), first.getSources());
                interference.add(first.getResult().getReg(), second.getResult().getReg());
            }
        }
    }
}
 

/**
 * Gets the parameter index for SSA registers that are method parameters.
 * {@code -1} is returned for non-parameter registers.
 *
 * @param ssaReg {@code >=0;} SSA register to look up
 * @return parameter index or {@code -1} if not a parameter
 */
private int getParameterIndexForReg(int ssaReg) {
    SsaInsn defInsn = ssaMeth.getDefinitionForRegister(ssaReg);
    if (defInsn == null) {
        return -1;
    }

    Rop opcode = defInsn.getOpcode();

    // opcode == null for phi insns.
    if (opcode != null && opcode.getOpcode() == RegOps.MOVE_PARAM) {
        CstInsn origInsn = (CstInsn) defInsn.getOriginalRopInsn();
        return  ((CstInteger) origInsn.getConstant()).getValue();
    }

    return -1;
}
 

/**
 * Removes all blocks containing only GOTOs from the control flow.
 * Although much of this work will be done later when converting
 * from rop to dex, not all simplification cases can be handled
 * there. Furthermore, any no-op block between the exit block and
 * blocks containing the real return or throw statements must be
 * removed.
 */
private void removeEmptyGotos() {
    final ArrayList<SsaBasicBlock> blocks = ssaMeth.getBlocks();

    ssaMeth.forEachBlockDepthFirst(false, new SsaBasicBlock.Visitor() {
        public void visitBlock(SsaBasicBlock b, SsaBasicBlock parent) {
            ArrayList<SsaInsn> insns = b.getInsns();

            if ((insns.size() == 1)
                    && (insns.get(0).getOpcode() == Rops.GOTO)) {
                BitSet preds = (BitSet) b.getPredecessors().clone();

                for (int i = preds.nextSetBit(0); i >= 0;
                        i = preds.nextSetBit(i + 1)) {
                    SsaBasicBlock pb = blocks.get(i);
                    pb.replaceSuccessor(b.getIndex(),
                            b.getPrimarySuccessorIndex());
                }
            }
        }
    });
}
 

/**
 * Removes all blocks containing only GOTOs from the control flow.
 * Although much of this work will be done later when converting
 * from rop to dex, not all simplification cases can be handled
 * there. Furthermore, any no-op block between the exit block and
 * blocks containing the real return or throw statements must be
 * removed.
 */
private void removeEmptyGotos() {
    final ArrayList<SsaBasicBlock> blocks = ssaMeth.getBlocks();

    ssaMeth.forEachBlockDepthFirst(false, new SsaBasicBlock.Visitor() {
        @Override
        public void visitBlock(SsaBasicBlock b, SsaBasicBlock parent) {
            ArrayList<SsaInsn> insns = b.getInsns();

            if ((insns.size() == 1)
                    && (insns.get(0).getOpcode() == Rops.GOTO)) {
                BitSet preds = (BitSet) b.getPredecessors().clone();

                for (int i = preds.nextSetBit(0); i >= 0;
                        i = preds.nextSetBit(i + 1)) {
                    SsaBasicBlock pb = blocks.get(i);
                    pb.replaceSuccessor(b.getIndex(),
                            b.getPrimarySuccessorIndex());
                }
            }
        }
    });
}
 

/**
 * From Appel algorithm 19.17.
 */
public void run() {
    List<SsaInsn> useList = ssaMeth.getUseListForRegister(regV);

    for (SsaInsn insn : useList) {
        nextFunction = NextFunction.DONE;

        if (insn instanceof PhiInsn) {
            // If s is a phi-function with V as it's ith argument.
            PhiInsn phi = (PhiInsn) insn;

            for (SsaBasicBlock pred :
                     phi.predBlocksForReg(regV, ssaMeth)) {
                blockN = pred;

                nextFunction = NextFunction.LIVE_OUT_AT_BLOCK;
                handleTailRecursion();
            }
        } else {
            blockN = insn.getBlock();
            statementIndex = blockN.getInsns().indexOf(insn);

            if (statementIndex < 0) {
                throw new RuntimeException(
                        "insn not found in it's own block");
            }

            nextFunction = NextFunction.LIVE_IN_AT_STATEMENT;
            handleTailRecursion();
        }
    }

    int nextLiveOutBlock;
    while ((nextLiveOutBlock = liveOutBlocks.nextSetBit(0)) >= 0) {
        blockN = ssaMeth.getBlocks().get(nextLiveOutBlock);
        liveOutBlocks.clear(nextLiveOutBlock);
        nextFunction = NextFunction.LIVE_OUT_AT_BLOCK;
        handleTailRecursion();
    }
}
 

/**
 * Returns true if the definition site of this register is a
 * move-param (ie, this is a method parameter).
 *
 * @param reg register in question
 * @return {@code true} if this is a method parameter
 */
protected boolean isDefinitionMoveParam(int reg) {
    SsaInsn defInsn = ssaMeth.getDefinitionForRegister(reg);

    if (defInsn instanceof NormalSsaInsn) {
        NormalSsaInsn ndefInsn = (NormalSsaInsn) defInsn;

        return ndefInsn.getOpcode().getOpcode() == RegOps.MOVE_PARAM;
    }

    return false;
}
 

/**
 * Converts an insn list to rop form.
 *
 * @param ssaInsns {@code non-null;} old instructions
 * @return {@code non-null;} immutable instruction list
 */
private InsnList convertInsns(ArrayList<SsaInsn> ssaInsns) {
    int insnCount = ssaInsns.size();
    InsnList result = new InsnList(insnCount);

    for (int i = 0; i < insnCount; i++) {
        result.set(i, ssaInsns.get(i).toRopInsn());
    }

    result.setImmutable();

    return result;
}
 

/**
 * Converts an insn list to rop form.
 *
 * @param ssaInsns {@code non-null;} old instructions
 * @return {@code non-null;} immutable instruction list
 */
private InsnList convertInsns(ArrayList<SsaInsn> ssaInsns) {
    int insnCount = ssaInsns.size();
    InsnList result = new InsnList(insnCount);

    for (int i = 0; i < insnCount; i++) {
        result.set(i, ssaInsns.get(i).toRopInsn());
    }

    result.setImmutable();

    return result;
}
 

/**
 * Validates that a basic block is a valid end predecessor. It must
 * end in a RETURN or a THROW. Throws a runtime exception on error.
 *
 * @param b {@code non-null;} block to validate
 * @throws RuntimeException on error
 */
private void verifyValidExitPredecessor(SsaBasicBlock b) {
    ArrayList<SsaInsn> insns = b.getInsns();
    SsaInsn lastInsn = insns.get(insns.size() - 1);
    Rop opcode = lastInsn.getOpcode();

    if (opcode.getBranchingness() != Rop.BRANCH_RETURN
            && opcode != Rops.THROW) {
        throw new RuntimeException("Exit predecessor must end"
                + " in valid exit statement.");
    }
}
 

/**
 * Validates that a basic block is a valid end predecessor. It must
 * end in a RETURN or a THROW. Throws a runtime exception on error.
 *
 * @param b {@code non-null;} block to validate
 * @throws RuntimeException on error
 */
private void verifyValidExitPredecessor(SsaBasicBlock b) {
    ArrayList<SsaInsn> insns = b.getInsns();
    SsaInsn lastInsn = insns.get(insns.size() - 1);
    Rop opcode = lastInsn.getOpcode();

    if (opcode.getBranchingness() != Rop.BRANCH_RETURN
            && opcode != Rops.THROW) {
        throw new RuntimeException("Exit predecessor must end"
                + " in valid exit statement.");
    }
}
 

/**
 * Returns true if the definition site of this register is a
 * move-param (ie, this is a method parameter).
 *
 * @param reg register in question
 * @return {@code true} if this is a method parameter
 */
protected boolean isDefinitionMoveParam(int reg) {
    SsaInsn defInsn = ssaMeth.getDefinitionForRegister(reg);

    if (defInsn instanceof NormalSsaInsn) {
        NormalSsaInsn ndefInsn = (NormalSsaInsn) defInsn;

        return ndefInsn.getOpcode().getOpcode() == RegOps.MOVE_PARAM;
    }

    return false;
}
 

/**
 * Returns the category (width) of the definition site of the register.
 * Returns {@code 1} for undefined registers.
 *
 * @param reg register
 * @return {@code 1..2}
 */
protected final int getCategoryForSsaReg(int reg) {
    SsaInsn definition = ssaMeth.getDefinitionForRegister(reg);

    if (definition == null) {
        // an undefined reg
        return 1;
    } else {
        return definition.getResult().getCategory();
    }
}
 

/**
 * Returns the category (width) of the definition site of the register.
 * Returns {@code 1} for undefined registers.
 *
 * @param reg register
 * @return {@code 1..2}
 */
protected final int getCategoryForSsaReg(int reg) {
    SsaInsn definition = ssaMeth.getDefinitionForRegister(reg);

    if (definition == null) {
        // an undefined reg
        return 1;
    } else {
        return definition.getResult().getCategory();
    }
}
 

/**
 * "v is live-out at s."
 */
private void liveOutAtStatement() {
    SsaInsn statement = blockN.getInsns().get(statementIndex);
    RegisterSpec rs = statement.getResult();

    if (!statement.isResultReg(regV)) {
        if (rs != null) {
            interference.add(regV, rs.getReg());
        }
        nextFunction = NextFunction.LIVE_IN_AT_STATEMENT;
    }
}
 

/**
 * From Appel algorithm 19.17.
 */
public void run() {
    List<SsaInsn> useList = ssaMeth.getUseListForRegister(regV);

    for (SsaInsn insn : useList) {
        nextFunction = NextFunction.DONE;

        if (insn instanceof PhiInsn) {
            // If s is a phi-function with V as it's ith argument.
            PhiInsn phi = (PhiInsn) insn;

            for (SsaBasicBlock pred :
                     phi.predBlocksForReg(regV, ssaMeth)) {
                blockN = pred;

                nextFunction = NextFunction.LIVE_OUT_AT_BLOCK;
                handleTailRecursion();
            }
        } else {
            blockN = insn.getBlock();
            statementIndex = blockN.getInsns().indexOf(insn);

            if (statementIndex < 0) {
                throw new RuntimeException(
                        "insn not found in it's own block");
            }

            nextFunction = NextFunction.LIVE_IN_AT_STATEMENT;
            handleTailRecursion();
        }
    }

    int nextLiveOutBlock;
    while ((nextLiveOutBlock = liveOutBlocks.nextSetBit(0)) >= 0) {
        blockN = ssaMeth.getBlocks().get(nextLiveOutBlock);
        liveOutBlocks.clear(nextLiveOutBlock);
        nextFunction = NextFunction.LIVE_OUT_AT_BLOCK;
        handleTailRecursion();
    }
}
 

/**
 * "v is live-out at s."
 */
private void liveOutAtStatement() {
    SsaInsn statement = blockN.getInsns().get(statementIndex);
    RegisterSpec rs = statement.getResult();

    if (!statement.isResultReg(regV)) {
        if (rs != null) {
            interference.add(regV, rs.getReg());
        }
        nextFunction = NextFunction.LIVE_IN_AT_STATEMENT;
    }
}
 

/**
 * From Appel algorithm 19.17.
 */
public void run() {
    List<SsaInsn> useList = ssaMeth.getUseListForRegister(regV);

    for (SsaInsn insn : useList) {
        nextFunction = NextFunction.DONE;

        if (insn instanceof PhiInsn) {
            // If s is a phi-function with V as it's ith argument.
            PhiInsn phi = (PhiInsn) insn;

            for (SsaBasicBlock pred :
                     phi.predBlocksForReg(regV, ssaMeth)) {
                blockN = pred;

                nextFunction = NextFunction.LIVE_OUT_AT_BLOCK;
                handleTailRecursion();
            }
        } else {
            blockN = insn.getBlock();
            statementIndex = blockN.getInsns().indexOf(insn);

            if (statementIndex < 0) {
                throw new RuntimeException(
                        "insn not found in it's own block");
            }

            nextFunction = NextFunction.LIVE_IN_AT_STATEMENT;
            handleTailRecursion();
        }
    }

    int nextLiveOutBlock;
    while ((nextLiveOutBlock = liveOutBlocks.nextSetBit(0)) >= 0) {
        blockN = ssaMeth.getBlocks().get(nextLiveOutBlock);
        liveOutBlocks.clear(nextLiveOutBlock);
        nextFunction = NextFunction.LIVE_OUT_AT_BLOCK;
        handleTailRecursion();
    }
}
 

/**
 * "v is live-out at s."
 */
private void liveOutAtStatement() {
    SsaInsn statement = blockN.getInsns().get(statementIndex);
    RegisterSpec rs = statement.getResult();

    if (!statement.isResultReg(regV)) {
        if (rs != null) {
            interference.add(regV, rs.getReg());
        }
        nextFunction = NextFunction.LIVE_IN_AT_STATEMENT;
    }
}