Function __fix_pcreladdr

app/src/main/cpp/And64InlineHook.cpp:329–424

//-------------------------------------------------------------------------

static bool __fix_pcreladdr(instruction inpp, instruction outpp, context *ctxp) {
    // Load a PC-relative address into a register
    // http://infocenter.arm.com/help/topic/com.arm.doc.100069_0608_00_en/pge1427897645644.html
    constexpr uint32_t msb = 8u;
    constexpr uint32_t lsb = 5u;
    constexpr uint32_t mask = 0x9f000000u; // 0b10011111000000000000000000000000
    constexpr uint32_t rmask = 0x0000001fu; // 0b00000000000000000000000000011111
    constexpr uint32_t lmask = 0xff00001fu; // 0b11111111000000000000000000011111
    constexpr uint32_t fmask = 0x00ffffffu; // 0b00000000111111111111111111111111
    constexpr uint32_t max_val = 0x001fffffu; // 0b00000000000111111111111111111111
    constexpr uint32_t op_adr = 0x10000000u; // "adr"  Rd, ADDR_PCREL21
    constexpr uint32_t op_adrp = 0x90000000u; // "adrp" Rd, ADDR_ADRP

    const uint32_t ins = *(*inpp);
    intptr_t current_idx;
    switch (ins & mask) {
        case op_adr: {
            current_idx = ctxp->get_and_set_current_index(*inpp, *outpp);
            int64_t lsb_bytes = static_cast<uint32_t>(ins << 1u) >> 30u;
            int64_t absolute_addr = reinterpret_cast<int64_t>(*inpp) +
                                    (((static_cast<int32_t>(ins << msb) >> (msb + lsb - 2u)) &
                                      ~3u) | lsb_bytes);
            int64_t new_pc_offset = static_cast<int64_t>(absolute_addr -
                                                         reinterpret_cast<int64_t>(*outpp));
            bool special_fix_type = ctxp->is_in_fixing_range(absolute_addr);
            if (!special_fix_type && llabs(new_pc_offset) > max_val) {
                if ((reinterpret_cast<uint64_t>(*outpp + 2) & 7u) != 0u) {
                    (*outpp)[0] = A64_NOP;
                    ctxp->reset_current_ins(current_idx, ++(*outpp));
                } //if

                (*outpp)[0] =
                        0x58000000u | (((8u >> 2u) << lsb) & ~mask) | (ins & rmask); // LDR #0x8
                (*outpp)[1] = 0x14000003u; // B #0xc
                memcpy(*outpp + 2, &absolute_addr, sizeof(absolute_addr));
                *outpp += 4;
            } else {
                if (special_fix_type) {
                    intptr_t ref_idx = ctxp->get_ref_ins_index(absolute_addr & ~3ull);
                    if (ref_idx <= current_idx) {
                        new_pc_offset = static_cast<int64_t>(ctxp->dat[ref_idx].ins -
                                                             reinterpret_cast<int64_t>(*outpp));
                    } else {
                        ctxp->insert_fix_map(ref_idx, *outpp, lsb, fmask);
                        new_pc_offset = 0;
                    } //if
                } //if

                // the lsb_bytes will never be changed, so we can use lmask to keep it
                (*outpp)[0] = (static_cast<uint32_t>(new_pc_offset << (lsb - 2u)) & fmask) |
                              (ins & lmask);
                ++(*outpp);
            } //if
        }
            break;
        case op_adrp: {
            current_idx = ctxp->get_and_set_current_index(*inpp, *outpp);
            int32_t lsb_bytes = static_cast<uint32_t>(ins << 1u) >> 30u;