Method rewriteClass

src/instrument.cpp:955–1053

}

Result BytecodeRewriter::rewriteClass() {
    u32 magic = get32();
    put32(magic);

    u32 version = get32();
    put32(version);

    _cpool_len = get16();
    u32 cpool_len_idx = _dst_len;
    put16(0); // to be patched later

    const u8* cpool_start = _src;

    _cpool = new Constant*[_cpool_len];
    for (int i = 1; i < _cpool_len; i += _cpool[i]->slots()) {
        _cpool[i] = getConstant();
    }

    const u8* cpool_end = _src;
    put(cpool_start, cpool_end - cpool_start);

    _recordEntry_cpool_idx = _cpool_len;
    putConstant(JVM_CONSTANT_Methodref, _cpool_len + 1, _cpool_len + 2);
    putConstant(JVM_CONSTANT_Class, _cpool_len + 3);
    putConstant(JVM_CONSTANT_NameAndType, _cpool_len + 4, _cpool_len + 5);
    putConstant("one/profiler/Instrument");
    putConstant("recordEntry");
    putConstant("()V");

    _recordExit_cpool_idx = _cpool_len + 6;
    putConstant(JVM_CONSTANT_Methodref, _cpool_len + 1, _cpool_len + 7);
    putConstant(JVM_CONSTANT_NameAndType, _cpool_len + 8, _cpool_len + 9);
    putConstant("recordExit");
    putConstant("(JJ)V");

    _recordExit_latency0_cpool_idx = _cpool_len + 10;
    putConstant(JVM_CONSTANT_Methodref, _cpool_len + 1, _cpool_len + 11);
    putConstant(JVM_CONSTANT_NameAndType, _cpool_len + 8, _cpool_len + 12);
    putConstant("(J)V");

    _nanoTime_cpool_idx = _cpool_len + 13;
    putConstant(JVM_CONSTANT_Methodref, _cpool_len + 14, _cpool_len + 15);
    putConstant(JVM_CONSTANT_Class, _cpool_len + 16);
    putConstant(JVM_CONSTANT_NameAndType, _cpool_len + 17, _cpool_len + 18);
    putConstant("java/lang/System");
    putConstant("nanoTime");
    putConstant("()J");

    // Flushed later to the buffer, after latency-related constants are written to the cpool
    u16 access_flags = get16();
    u16 this_class = get16();

    u16 class_name_index = _cpool[this_class]->info();
    _class_name = _cpool[class_name_index];
    // We should not instrument classes from one.profiler.* to avoid infinite recursion
    if (_class_name->info() >= PROFILER_PACKAGE_LEN &&
        strncmp(_class_name->utf8(), PROFILER_PACKAGE, PROFILER_PACKAGE_LEN) == 0) {
        return Result::PROFILER_CLASS;