Examples with SsaBasicBlock com.android.dx.ssa.SsaBasicBlock used on opensource projects

Example 6 with SsaBasicBlock

use of com.android.dx.ssa.SsaBasicBlock in project J2ME-Loader by nikita36078.

the class FirstFitLocalCombiningAllocator method handleCheckCastResults.

/**
 * Handles check cast results to reuse the same source register.
 * Inserts a move if it can't map the same register to both and the
 * check cast is not caught.
 */
private void handleCheckCastResults() {
    for (NormalSsaInsn insn : moveResultPseudoInsns) {
        RegisterSpec moveRegSpec = insn.getResult();
        int moveReg = moveRegSpec.getReg();
        BitSet predBlocks = insn.getBlock().getPredecessors();
        // Expect one predecessor block only
        if (predBlocks.cardinality() != 1) {
            continue;
        }
        SsaBasicBlock predBlock = ssaMeth.getBlocks().get(predBlocks.nextSetBit(0));
        ArrayList<SsaInsn> insnList = predBlock.getInsns();
        /**
         * If the predecessor block has a check-cast, it will be the last
         * instruction
         */
        SsaInsn checkCastInsn = insnList.get(insnList.size() - 1);
        if (checkCastInsn.getOpcode().getOpcode() != RegOps.CHECK_CAST) {
            continue;
        }
        RegisterSpec checkRegSpec = checkCastInsn.getSources().get(0);
        int checkReg = checkRegSpec.getReg();
        /**
         * See if either register is already mapped. Most likely the move
         * result will be mapped already since the cast result is stored
         * in a local variable.
         */
        int category = checkRegSpec.getCategory();
        boolean moveMapped = ssaRegsMapped.get(moveReg);
        boolean checkMapped = ssaRegsMapped.get(checkReg);
        if (moveMapped & !checkMapped) {
            int moveRopReg = mapper.oldToNew(moveReg);
            checkMapped = tryMapReg(checkRegSpec, moveRopReg, category);
        }
        if (checkMapped & !moveMapped) {
            int checkRopReg = mapper.oldToNew(checkReg);
            moveMapped = tryMapReg(moveRegSpec, checkRopReg, category);
        }
        // Map any unmapped registers to anything available
        if (!moveMapped || !checkMapped) {
            int ropReg = findNextUnreservedRopReg(paramRangeEnd, category);
            ArrayList<RegisterSpec> ssaRegs = new ArrayList<RegisterSpec>(2);
            ssaRegs.add(moveRegSpec);
            ssaRegs.add(checkRegSpec);
            while (!tryMapRegs(ssaRegs, ropReg, category, false)) {
                ropReg = findNextUnreservedRopReg(ropReg + 1, category);
            }
        }
        /*
             * If source and result have a different mapping, insert a move so
             * they can have the same mapping. Don't do this if the check cast
             * is caught, since it will overwrite a potentially live value.
             */
        boolean hasExceptionHandlers = checkCastInsn.getOriginalRopInsn().getCatches().size() != 0;
        int moveRopReg = mapper.oldToNew(moveReg);
        int checkRopReg = mapper.oldToNew(checkReg);
        if (moveRopReg != checkRopReg && !hasExceptionHandlers) {
            ((NormalSsaInsn) checkCastInsn).changeOneSource(0, insertMoveBefore(checkCastInsn, checkRegSpec));
            addMapping(checkCastInsn.getSources().get(0), moveRopReg);
        }
    }
}

Example 7 with SsaBasicBlock

use of com.android.dx.ssa.SsaBasicBlock in project J2ME-Loader by nikita36078.

the class RegisterAllocator method insertMoveBefore.

/**
 * 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;
}

Example 8 with SsaBasicBlock

use of com.android.dx.ssa.SsaBasicBlock in project J2ME-Loader by nikita36078.

the class SsaToRop method convertBasicBlocks.

/**
 * @return rop-form basic block list
 */
private BasicBlockList convertBasicBlocks() {
    ArrayList<SsaBasicBlock> blocks = ssaMeth.getBlocks();
    // Exit block may be null.
    SsaBasicBlock exitBlock = ssaMeth.getExitBlock();
    ssaMeth.computeReachability();
    int ropBlockCount = ssaMeth.getCountReachableBlocks();
    // Don't count the exit block, if it exists and is reachable.
    ropBlockCount -= (exitBlock != null && exitBlock.isReachable()) ? 1 : 0;
    BasicBlockList result = new BasicBlockList(ropBlockCount);
    // Convert all the reachable blocks except the exit block.
    int ropBlockIndex = 0;
    for (SsaBasicBlock b : blocks) {
        if (b.isReachable() && b != exitBlock) {
            result.set(ropBlockIndex++, convertBasicBlock(b));
        }
    }
    // The exit block, which is discarded, must do nothing.
    if (exitBlock != null && exitBlock.getInsns().size() != 0) {
        throw new RuntimeException("Exit block must have no insns when leaving SSA form");
    }
    return result;
}

Example 9 with SsaBasicBlock

use of com.android.dx.ssa.SsaBasicBlock in project J2ME-Loader by nikita36078.

the class SsaToRop method removePhiFunctions.

/**
 * See Appel 19.6. To remove the phi instructions in an edge-split
 * SSA representation we know we can always insert a move in a
 * predecessor block.
 */
private void removePhiFunctions() {
    ArrayList<SsaBasicBlock> blocks = ssaMeth.getBlocks();
    for (SsaBasicBlock block : blocks) {
        // Add moves in all the pred blocks for each phi insn.
        block.forEachPhiInsn(new PhiVisitor(blocks));
        // Delete the phi insns.
        block.removeAllPhiInsns();
    }
    /*
         * After all move insns have been added, sort them so they don't
         * destructively interfere.
         */
    for (SsaBasicBlock block : blocks) {
        block.scheduleMovesFromPhis();
    }
}

Example 10 with SsaBasicBlock

use of com.android.dx.ssa.SsaBasicBlock in project buck by facebook.

the class LivenessAnalyzer method coInterferePhis.

/**
     * 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());
            }
        }
    }
}