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

Example 16 with TypedConstant

use of com.android.dx.rop.cst.TypedConstant in project J2ME-Loader by nikita36078.

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));
        }
    }
}