How LIR append to CU ?

/*
 * The following are building blocks to construct low-level IRs with 0 - 4
 * operands.
 */
static ArmLIR *newLIR0(CompilationUnit *cUnit, ArmOpcode opcode)
{
    ArmLIR *insn = (ArmLIR *) dvmCompilerNew(sizeof(ArmLIR), true);
    assert(isPseudoOpcode(opcode) || (EncodingMap[opcode].flags & NO_OPERAND));
    insn->opcode = opcode;
    setupResourceMasks(insn);
    dvmCompilerAppendLIR(cUnit, (LIR *) insn);
    return insn;
}

static ArmLIR *newLIR1(CompilationUnit *cUnit, ArmOpcode opcode,
                           int dest)
{
    ArmLIR *insn = (ArmLIR *) dvmCompilerNew(sizeof(ArmLIR), true);
    assert(isPseudoOpcode(opcode) || (EncodingMap[opcode].flags & IS_UNARY_OP));
    insn->opcode = opcode;
    insn->operands[0] = dest;
    setupResourceMasks(insn);
    dvmCompilerAppendLIR(cUnit, (LIR *) insn);
    return insn;
}

static ArmLIR *newLIR2(CompilationUnit *cUnit, ArmOpcode opcode,
                           int dest, int src1)
{
    ArmLIR *insn = (ArmLIR *) dvmCompilerNew(sizeof(ArmLIR), true);
    assert(isPseudoOpcode(opcode) ||
           (EncodingMap[opcode].flags & IS_BINARY_OP));
    insn->opcode = opcode;
    insn->operands[0] = dest;
    insn->operands[1] = src1;
    setupResourceMasks(insn);
    dvmCompilerAppendLIR(cUnit, (LIR *) insn);
    return insn;
}

static ArmLIR *newLIR3(CompilationUnit *cUnit, ArmOpcode opcode,
                           int dest, int src1, int src2)
{
    ArmLIR *insn = (ArmLIR *) dvmCompilerNew(sizeof(ArmLIR), true);
    if (!(EncodingMap[opcode].flags & IS_TERTIARY_OP)) {
        ALOGE("Bad LIR3: %s[%d]",EncodingMap[opcode].name,opcode);
    }
    assert(isPseudoOpcode(opcode) ||
           (EncodingMap[opcode].flags & IS_TERTIARY_OP));
    insn->opcode = opcode;
    insn->operands[0] = dest;
    insn->operands[1] = src1;
    insn->operands[2] = src2;
    setupResourceMasks(insn);
    dvmCompilerAppendLIR(cUnit, (LIR *) insn);
    return insn;
}

#if defined(_ARMV7_A) || defined(_ARMV7_A_NEON)
static ArmLIR *newLIR4(CompilationUnit *cUnit, ArmOpcode opcode,
                           int dest, int src1, int src2, int info)
{
    ArmLIR *insn = (ArmLIR *) dvmCompilerNew(sizeof(ArmLIR), true);
    assert(isPseudoOpcode(opcode) ||
           (EncodingMap[opcode].flags & IS_QUAD_OP));
    insn->opcode = opcode;
    insn->operands[0] = dest;
    insn->operands[1] = src1;
    insn->operands[2] = src2;
    insn->operands[3] = info;
    setupResourceMasks(insn);
    dvmCompilerAppendLIR(cUnit, (LIR *) insn);
    return insn;
}
#endif