Function ApplySlideInfoV2

view/sharedcache/core/SlideInfo.cpp:88–157

}

void ApplySlideInfoV2(MappedFileAccessor& accessor, const SlideMappingInfo& mapping)
{
	auto rebaseChain = [&](const dyld_cache_slide_info_v2& slideInfo, uint64_t pageContent, uint16_t startOffset) {
		// TODO: This is always zero?
		// TODO: This is probably something for runtime offsets provided to the shared cache.
		uintptr_t slideAmount = 0;

		auto deltaMask = slideInfo.delta_mask;
		auto valueMask = ~deltaMask;
		auto valueAdd = slideInfo.value_add;

		auto deltaShift = CountTrailingZeros(deltaMask) - 2;

		uint32_t pageOffset = startOffset;
		uint32_t delta = 1;
		while (delta != 0)
		{
			uint64_t loc = pageContent + pageOffset;
			uintptr_t rawValue = accessor.ReadUInt64(loc);
			delta = (uint32_t)((rawValue & deltaMask) >> deltaShift);
			uintptr_t value = (rawValue & valueMask);
			if (value != 0)
			{
				value += valueAdd;
				// TODO: slideAmount += value?
				// TODO: slideAmount is always zero? What is this suppose to do?
				value += slideAmount;
			}
			pageOffset += delta;
			accessor.WritePointer(loc, value);
		}
	};

	uint64_t extrasOffset = mapping.address + mapping.slideInfoV2.page_extras_offset;
	uint64_t pageStartsOffset = mapping.address + sizeof(dyld_cache_slide_info_v2);
	uint64_t pageStartCount = mapping.slideInfoV2.page_starts_count;
	uint64_t pageSize = mapping.slideInfoV2.page_size;

	auto cursor = pageStartsOffset;
	for (size_t i = 0; i < pageStartCount; i++)
	{
		uint16_t start = accessor.ReadUInt16(cursor);
		cursor += sizeof(uint16_t);
		if (start == DYLD_CACHE_SLIDE_PAGE_ATTR_NO_REBASE)
			continue;

		if (start & DYLD_CACHE_SLIDE_PAGE_ATTR_EXTRA)
		{
			int j = (start & 0x3FFF);
			bool done = false;
			do
			{
				uint64_t extraCursor = extrasOffset + (j * sizeof(uint16_t));
				auto extra = accessor.ReadUInt16(extraCursor);
				uint16_t aStart = extra;
				uint64_t page = mapping.mappingInfo.fileOffset + (pageSize * i);
				uint16_t pageStartOffset = (aStart & 0x3FFF) * 4;
				rebaseChain(mapping.slideInfoV2, page, pageStartOffset);