Fix truncated drop pattern on 32bit -> 64bit cross compilation #31283
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When cross compiling for a target that has a larger usize type than the host system, we use a truncated value to mark data as dropped, eventually leading to drop calls on already dropped data. To properly handle this, the drop pattern needs to be of type u64. Since C_integral truncates its given value to the requested size anyway, we can also drop the function that chose between the u32 and u64 values, and always use the u64 constant. Fixes rust-lang#31139
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Thanks @dotdash! I was wondering of ways we might test this but I couldn't think of one (short of inspecting IR), so r+ from me at least |
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📌 Commit fdf65e7 has been approved by |
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⌛ Testing commit fdf65e7 with merge 074f49a... |
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When cross compiling for a target that has a larger usize type than the host system, we use a truncated value to mark data as dropped, eventually leading to drop calls on already dropped data. To properly handle this, the drop pattern needs to be of type u64. Since C_integral truncates its given value to the requested size anyway, we can also drop the function that chose between the u32 and u64 values, and always use the u64 constant. Fixes #31139 r? @pnkfelix
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When cross compiling for a target that has a larger usize type than the
host system, we use a truncated value to mark data as dropped,
eventually leading to drop calls on already dropped data. To properly
handle this, the drop pattern needs to be of type u64.
Since C_integral truncates its given value to the requested size anyway,
we can also drop the function that chose between the u32 and u64 values,
and always use the u64 constant.
Fixes #31139
r? @pnkfelix