Examples with Constant com.android.dx.rop.cst.Constant used on opensource projects

Example 16 with Constant

use of com.android.dx.rop.cst.Constant in project buck by facebook.

the class SCCP method simulateMath.

/**
     * Simulates math insns, if possible.
     *
     * @param insn non-null insn to simulate
     * @param resultType basic type of the result
     * @return constant result or null if not simulatable.
     */
private Constant simulateMath(SsaInsn insn, int resultType) {
    Insn ropInsn = insn.getOriginalRopInsn();
    int opcode = insn.getOpcode().getOpcode();
    RegisterSpecList sources = insn.getSources();
    int regA = sources.get(0).getReg();
    Constant cA;
    Constant cB;
    if (latticeValues[regA] != CONSTANT) {
        cA = null;
    } else {
        cA = latticeConstants[regA];
    }
    if (sources.size() == 1) {
        CstInsn cstInsn = (CstInsn) ropInsn;
        cB = cstInsn.getConstant();
    } else {
        /* sources.size() == 2 */
        int regB = sources.get(1).getReg();
        if (latticeValues[regB] != CONSTANT) {
            cB = null;
        } else {
            cB = latticeConstants[regB];
        }
    }
    if (cA == null || cB == null) {
        //TODO handle a constant of 0 with MUL or AND
        return null;
    }
    switch(resultType) {
        case Type.BT_INT:
            int vR;
            boolean skip = false;
            int vA = ((CstInteger) cA).getValue();
            int vB = ((CstInteger) cB).getValue();
            switch(opcode) {
                case RegOps.ADD:
                    vR = vA + vB;
                    break;
                case RegOps.SUB:
                    // 1 source for reverse sub, 2 sources for regular sub
                    if (sources.size() == 1) {
                        vR = vB - vA;
                    } else {
                        vR = vA - vB;
                    }
                    break;
                case RegOps.MUL:
                    vR = vA * vB;
                    break;
                case RegOps.DIV:
                    if (vB == 0) {
                        skip = true;
                        // just to hide a warning
                        vR = 0;
                    } else {
                        vR = vA / vB;
                    }
                    break;
                case RegOps.AND:
                    vR = vA & vB;
                    break;
                case RegOps.OR:
                    vR = vA | vB;
                    break;
                case RegOps.XOR:
                    vR = vA ^ vB;
                    break;
                case RegOps.SHL:
                    vR = vA << vB;
                    break;
                case RegOps.SHR:
                    vR = vA >> vB;
                    break;
                case RegOps.USHR:
                    vR = vA >>> vB;
                    break;
                case RegOps.REM:
                    if (vB == 0) {
                        skip = true;
                        // just to hide a warning
                        vR = 0;
                    } else {
                        vR = vA % vB;
                    }
                    break;
                default:
                    throw new RuntimeException("Unexpected op");
            }
            return skip ? null : CstInteger.make(vR);
        default:
            // not yet supported
            return null;
    }
}

Example 17 with Constant

use of com.android.dx.rop.cst.Constant in project buck by facebook.

the class SCCP method simulateBranch.

/**
     * Simulates branch insns, if possible. Adds reachable successor blocks
     * to the CFG worklists.
     * @param insn branch to simulate
     */
private void simulateBranch(SsaInsn insn) {
    Rop opcode = insn.getOpcode();
    RegisterSpecList sources = insn.getSources();
    boolean constantBranch = false;
    boolean constantSuccessor = false;
    // Check if the insn is a branch with a constant condition
    if (opcode.getBranchingness() == Rop.BRANCH_IF) {
        Constant cA = null;
        Constant cB = null;
        RegisterSpec specA = sources.get(0);
        int regA = specA.getReg();
        if (!ssaMeth.isRegALocal(specA) && latticeValues[regA] == CONSTANT) {
            cA = latticeConstants[regA];
        }
        if (sources.size() == 2) {
            RegisterSpec specB = sources.get(1);
            int regB = specB.getReg();
            if (!ssaMeth.isRegALocal(specB) && latticeValues[regB] == CONSTANT) {
                cB = latticeConstants[regB];
            }
        }
        // Calculate the result of the condition
        if (cA != null && sources.size() == 1) {
            switch(((TypedConstant) cA).getBasicType()) {
                case Type.BT_INT:
                    constantBranch = true;
                    int vA = ((CstInteger) cA).getValue();
                    switch(opcode.getOpcode()) {
                        case RegOps.IF_EQ:
                            constantSuccessor = (vA == 0);
                            break;
                        case RegOps.IF_NE:
                            constantSuccessor = (vA != 0);
                            break;
                        case RegOps.IF_LT:
                            constantSuccessor = (vA < 0);
                            break;
                        case RegOps.IF_GE:
                            constantSuccessor = (vA >= 0);
                            break;
                        case RegOps.IF_LE:
                            constantSuccessor = (vA <= 0);
                            break;
                        case RegOps.IF_GT:
                            constantSuccessor = (vA > 0);
                            break;
                        default:
                            throw new RuntimeException("Unexpected op");
                    }
                    break;
                default:
            }
        } else if (cA != null && cB != null) {
            switch(((TypedConstant) cA).getBasicType()) {
                case Type.BT_INT:
                    constantBranch = true;
                    int vA = ((CstInteger) cA).getValue();
                    int vB = ((CstInteger) cB).getValue();
                    switch(opcode.getOpcode()) {
                        case RegOps.IF_EQ:
                            constantSuccessor = (vA == vB);
                            break;
                        case RegOps.IF_NE:
                            constantSuccessor = (vA != vB);
                            break;
                        case RegOps.IF_LT:
                            constantSuccessor = (vA < vB);
                            break;
                        case RegOps.IF_GE:
                            constantSuccessor = (vA >= vB);
                            break;
                        case RegOps.IF_LE:
                            constantSuccessor = (vA <= vB);
                            break;
                        case RegOps.IF_GT:
                            constantSuccessor = (vA > vB);
                            break;
                        default:
                            throw new RuntimeException("Unexpected op");
                    }
                    break;
                default:
            }
        }
    }
    /*
         * If condition is constant, add only the target block to the
         * worklist. Otherwise, add all successors to the worklist.
         */
    SsaBasicBlock block = insn.getBlock();
    if (constantBranch) {
        int successorBlock;
        if (constantSuccessor) {
            successorBlock = block.getSuccessorList().get(1);
        } else {
            successorBlock = block.getSuccessorList().get(0);
        }
        addBlockToWorklist(ssaMeth.getBlocks().get(successorBlock));
        branchWorklist.add(insn);
    } else {
        for (int i = 0; i < block.getSuccessorList().size(); i++) {
            int successorBlock = block.getSuccessorList().get(i);
            addBlockToWorklist(ssaMeth.getBlocks().get(successorBlock));
        }
    }
}

Example 18 with Constant

use of com.android.dx.rop.cst.Constant in project buck by facebook.

the class SCCP method simulateStmt.

/**
     * Simulates a statement and set the result lattice value.
     * @param insn instruction to simulate
     */
private void simulateStmt(SsaInsn insn) {
    Insn ropInsn = insn.getOriginalRopInsn();
    if (ropInsn.getOpcode().getBranchingness() != Rop.BRANCH_NONE || ropInsn.getOpcode().isCallLike()) {
        simulateBranch(insn);
    }
    int opcode = insn.getOpcode().getOpcode();
    RegisterSpec result = insn.getResult();
    if (result == null) {
        // Find move-result-pseudo result for int div and int rem
        if (opcode == RegOps.DIV || opcode == RegOps.REM) {
            SsaBasicBlock succ = insn.getBlock().getPrimarySuccessor();
            result = succ.getInsns().get(0).getResult();
        } else {
            return;
        }
    }
    int resultReg = result.getReg();
    int resultValue = VARYING;
    Constant resultConstant = null;
    switch(opcode) {
        case RegOps.CONST:
            {
                CstInsn cstInsn = (CstInsn) ropInsn;
                resultValue = CONSTANT;
                resultConstant = cstInsn.getConstant();
                break;
            }
        case RegOps.MOVE:
            {
                if (insn.getSources().size() == 1) {
                    int sourceReg = insn.getSources().get(0).getReg();
                    resultValue = latticeValues[sourceReg];
                    resultConstant = latticeConstants[sourceReg];
                }
                break;
            }
        case RegOps.ADD:
        case RegOps.SUB:
        case RegOps.MUL:
        case RegOps.DIV:
        case RegOps.AND:
        case RegOps.OR:
        case RegOps.XOR:
        case RegOps.SHL:
        case RegOps.SHR:
        case RegOps.USHR:
        case RegOps.REM:
            {
                resultConstant = simulateMath(insn, result.getBasicType());
                if (resultConstant != null) {
                    resultValue = CONSTANT;
                }
                break;
            }
        case RegOps.MOVE_RESULT_PSEUDO:
            {
                if (latticeValues[resultReg] == CONSTANT) {
                    resultValue = latticeValues[resultReg];
                    resultConstant = latticeConstants[resultReg];
                }
                break;
            }
        // TODO: Eliminate check casts that we can prove the type of.
        default:
            {
            }
    }
    if (setLatticeValueTo(resultReg, resultValue, resultConstant)) {
        addUsersToWorklist(resultReg, resultValue);
    }
}

Example 19 with Constant

use of com.android.dx.rop.cst.Constant in project buck by facebook.

the class CodeItem method addContents.

/** {@inheritDoc} */
public void addContents(DexFile file) {
    MixedItemSection byteData = file.getByteData();
    TypeIdsSection typeIds = file.getTypeIds();
    if (code.hasPositions() || code.hasLocals()) {
        debugInfo = new DebugInfoItem(code, isStatic, ref);
        byteData.add(debugInfo);
    }
    if (code.hasAnyCatches()) {
        for (Type type : code.getCatchTypes()) {
            typeIds.intern(type);
        }
        catches = new CatchStructs(code);
    }
    for (Constant c : code.getInsnConstants()) {
        file.internIfAppropriate(c);
    }
}

Example 20 with Constant

use of com.android.dx.rop.cst.Constant in project buck by facebook.

the class ConstCollector method getConstsSortedByCountUse.

/**
     * Gets all of the collectable constant values used in this method,
     * sorted by most used first. Skips non-collectable consts, such as
     * non-string object constants
     *
     * @return {@code non-null;} list of constants in most-to-least used order
     */
private ArrayList<TypedConstant> getConstsSortedByCountUse() {
    int regSz = ssaMeth.getRegCount();
    final HashMap<TypedConstant, Integer> countUses = new HashMap<TypedConstant, Integer>();
    /*
         * Each collected constant can be used by just one local
         * (used only if COLLECT_ONE_LOCAL is true).
         */
    final HashSet<TypedConstant> usedByLocal = new HashSet<TypedConstant>();
    // Count how many times each const value is used.
    for (int i = 0; i < regSz; i++) {
        SsaInsn insn = ssaMeth.getDefinitionForRegister(i);
        if (insn == null || insn.getOpcode() == null)
            continue;
        RegisterSpec result = insn.getResult();
        TypeBearer typeBearer = result.getTypeBearer();
        if (!typeBearer.isConstant())
            continue;
        TypedConstant cst = (TypedConstant) typeBearer;
        // Find defining instruction for move-result-pseudo instructions
        if (insn.getOpcode().getOpcode() == RegOps.MOVE_RESULT_PSEUDO) {
            int pred = insn.getBlock().getPredecessors().nextSetBit(0);
            ArrayList<SsaInsn> predInsns;
            predInsns = ssaMeth.getBlocks().get(pred).getInsns();
            insn = predInsns.get(predInsns.size() - 1);
        }
        if (insn.canThrow()) {
            /*
                 * Don't move anything other than strings -- the risk
                 * of changing where an exception is thrown is too high.
                 */
            if (!(cst instanceof CstString) || !COLLECT_STRINGS) {
                continue;
            }
            /*
                 * We can't move any throwable const whose throw will be
                 * caught, so don't count them.
                 */
            if (insn.getBlock().getSuccessors().cardinality() > 1) {
                continue;
            }
        }
        /*
             * TODO: Might be nice to try and figure out which local
             * wins most when collected.
             */
        if (ssaMeth.isRegALocal(result)) {
            if (!COLLECT_ONE_LOCAL) {
                continue;
            } else {
                if (usedByLocal.contains(cst)) {
                    // Count one local usage only.
                    continue;
                } else {
                    usedByLocal.add(cst);
                }
            }
        }
        Integer has = countUses.get(cst);
        if (has == null) {
            countUses.put(cst, 1);
        } else {
            countUses.put(cst, has + 1);
        }
    }
    // Collect constants that have been reused.
    ArrayList<TypedConstant> constantList = new ArrayList<TypedConstant>();
    for (Map.Entry<TypedConstant, Integer> entry : countUses.entrySet()) {
        if (entry.getValue() > 1) {
            constantList.add(entry.getKey());
        }
    }
    // Sort by use, with most used at the beginning of the list.
    Collections.sort(constantList, new Comparator<Constant>() {

        public int compare(Constant a, Constant b) {
            int ret;
            ret = countUses.get(b) - countUses.get(a);
            if (ret == 0) {
                /*
                     * Provide sorting determinisim for constants with same
                     * usage count.
                     */
                ret = a.compareTo(b);
            }
            return ret;
        }

        @Override
        public boolean equals(Object obj) {
            return obj == this;
        }
    });
    return constantList;
}