This regressed in 0a906f553fe7699d1c863a464211f74b6c306a0f, I think (though I haven't confirmed it). Mario Tennis and Luigi's Mansion both use these for some reason (as far as I can tell, the data isn't actually used; it's just extra data included for no reason)
DataReader is generally jank - it has a start and end pointer, but the end pointer is generally not used, and all of the vertex loaders mostly bypassed it anyways.
Wrapper code (the vertex loaer test, as well as Fifo.cpp and OpcodeDecoding.cpp) still uses it, as does the software vertex loader (which is not a subclass of VertexLoader). These can probably be eliminated later.
0e02ddcf52ed86060ac1a0a85fa144738fa5163c removed separate logic for tiled versus non-tiled EFB peek caches, and as part of that made it so that color peeks updated the frame access mask even when a non-tiled cache is in use. However, the same change was not made for depth peeks. I'm not sure if this affected anything in practice.
I originally added these in 2b1d1038a6acf0acf75b03ca93c85de6fe6cdf18, for both the TPipelineFunction and the size. The size was moved into the header in fdcd2b7d009cece6ad090143ce954aed713bb11c (making the size functions obsolete), but it seems that the functions themselves are no longer needed now.
I think I didn't use this approach before because it would have required ComponentFormatTable and ComponentCountRow to be templated, which would end up resulting in lines that were too long and thus wrapped in awkward places. (I *think* they didn't get inferred properly.) Now that we only need TPipelineFunction, the templating is not needed, and this ends up being a more readable version of the version with the wrapper functions.
Rather than makring some parts of VertexLoaderManager dirty in some places and some in others, do it all in VideoState. Also, since CPState no longer contains pointers/non-CP data after d039b1bc0dfaba2a88036468b6d971bb1d7e463d, we can just use p.Do on it instead of manually saving each field.
This was added in 385d8e2b15c8accce3b4e4b4f3dc90f63e3fbee4, but became somewhat redundant with Do in 4c7bbd96e435a7516b05d3e8c791ab41505e2e0f, and completely redundant now that std::is_trivially_copyable_v is well-supported.
Texture dumping can already be done using VideoCommon's system (and in fact the same setting already enabled *both* of these). Dumping objects/TEV stages/texture fetches doesn't currently have an equivalent, but could be added to the FIFO player instead.
