Memmap: Replace GetPointer with GetSpanForAddress #12705
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JosJuice
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Tilka
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Apr 13, 2024
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It seems that this PR breaks the decoding of C8 textures in the software backend, but I can't find anything wrong when re-reading the code... Maybe someone with more experience of the graphics backends can find something when reviewing the code? |
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I fixed three instances of an issue but there might be more. Note that FifoCI is currently down. |
To ensure memory safety, callers of GetPointer have to perform a bounds check. But how is this bounds check supposed to be performed? GetPointerForRange contained one implementation of a bounds check, but it was cumbersome, and it also isn't obvious why it's correct. To make doing the right thing easier, this commit changes GetPointer to return a span that tells the caller how many bytes it's allowed to access.
Now only VertexLoader remains... But that one might be tricky.
Happened to find this when working on the previous commit.
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Ah, I need to multiply the index by |
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To ensure memory safety, callers of GetPointer have to perform a bounds check. But how is this bounds check supposed to be performed? GetPointerForRange contained one implementation of a bounds check, but it was cumbersome, and it also isn't obvious why it's correct.
To make doing the right thing easier, the first commit of this PR changes GetPointer to return a span that tells the caller how many bytes it's allowed to access. Then, the second commit adds bounds checks to two of the three callers of GetPointer. The third caller, VertexLoader, will have to wait due to its tight optimization.