Method initOffsets

src/vmStructs.cpp:147–438

}

void VMStructs::initOffsets() {
    uintptr_t entry = readSymbol("gHotSpotVMStructs");
    uintptr_t stride = readSymbol("gHotSpotVMStructEntryArrayStride");
    uintptr_t type_offset = readSymbol("gHotSpotVMStructEntryTypeNameOffset");
    uintptr_t field_offset = readSymbol("gHotSpotVMStructEntryFieldNameOffset");
    uintptr_t offset_offset = readSymbol("gHotSpotVMStructEntryOffsetOffset");
    uintptr_t address_offset = readSymbol("gHotSpotVMStructEntryAddressOffset");

    if (entry != 0 && stride != 0) {
        for (;; entry += stride) {
            const char* type = *(const char**)(entry + type_offset);
            const char* field = *(const char**)(entry + field_offset);
            if (type == NULL || field == NULL) {
                break;
            }

            if (strcmp(type, "Klass") == 0) {
                if (strcmp(field, "_name") == 0) {
                    _klass_name_offset = *(int*)(entry + offset_offset);
                }
            } else if (strcmp(type, "Symbol") == 0) {
                if (strcmp(field, "_length") == 0) {
                    _symbol_length_offset = *(int*)(entry + offset_offset);
                } else if (strcmp(field, "_length_and_refcount") == 0) {
                    _symbol_length_and_refcount_offset = *(int*)(entry + offset_offset);
                } else if (strcmp(field, "_body") == 0) {
                    _symbol_body_offset = *(int*)(entry + offset_offset);
                }
            } else if (strcmp(type, "oopDesc") == 0) {
                if (strcmp(field, "_metadata._klass") == 0) {
                    _oop_klass_offset = *(int*)(entry + offset_offset);
                }
            } else if (strcmp(type, "Universe") == 0 || strcmp(type, "CompressedKlassPointers") == 0) {
                if (strcmp(field, "_narrow_klass._base") == 0 || strcmp(field, "_base") == 0) {
                    _narrow_klass_base_addr = *(char***)(entry + address_offset);
                } else if (strcmp(field, "_narrow_klass._shift") == 0 || strcmp(field, "_shift") == 0) {
                    _narrow_klass_shift_addr = *(int**)(entry + address_offset);
                } else if (strcmp(field, "_collectedHeap") == 0) {
                    _collected_heap_addr = *(char***)(entry + address_offset);
                }
            } else if (strcmp(type, "CollectedHeap") == 0) {
                if (strcmp(field, "_reserved") == 0) {
                    _collected_heap_reserved_offset = *(int*)(entry + offset_offset);
                }
            } else if (strcmp(type, "MemRegion") == 0) {
                if (strcmp(field, "_start") == 0) {
                    _region_start_offset = *(int*)(entry + offset_offset);
                } else if (strcmp(field, "_word_size") == 0) {
                    _region_size_offset = *(int*)(entry + offset_offset);
                }
            } else if (strcmp(type, "CompiledMethod") == 0 || strcmp(type, "nmethod") == 0) {
                if (strcmp(field, "_method") == 0) {
                    _nmethod_method_offset = *(int*)(entry + offset_offset);
                } else if (strcmp(field, "_verified_entry_offset") == 0) {
                    _nmethod_entry_offset = *(int*)(entry + offset_offset);
                } else if (strcmp(field, "_verified_entry_point") == 0) {
                    _nmethod_entry_offset = - *(int*)(entry + offset_offset);
                } else if (strcmp(field, "_state") == 0) {