[hot_reload] Don't look at delta method table rows #57798
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Call a method for the first time after an update has been applied to it. This will check that the interpreter or JIT does not have to rely on cached information from the baseline (about the method signature, for example) and that it can compute it from the delta.
The issue is that the ParamList column in EnC deltas is a "suppressed column" that has the value 0. So when a method is updated if we use the value directly, we will break, for example - `mono_metadata_get_param_attrs` which expects a non-zero index in that column. CoreCLR solves this by having a set of suppressed columns that are never updated by deltas. (CoreCLR's model is to directly mutate the tables of the baseline image). In Mono we can eventually do the same thing by writing the value from the previous generation into the current delta's row. But right now since we don't allow parameter modifications, and the only column on a Method table that we allow to be modified is the RVA - which we look up specially - we can just always return the baseline image row for the method table. Fixes dotnet#57643
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I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label. |
thaystg
approved these changes
Aug 20, 2021
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/backport to release/6.0-rc1 |
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Started backporting to release/6.0-rc1: https://github.com/dotnet/runtime/actions/runs/1149439918 |
ghost
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The issue is that the ParamList column in EnC deltas is a "suppressed column" that has the value 0. So when a method is updated if we use the value directly, we will break, for example -
mono_metadata_get_param_attrswhich expects a non-zero index in that column.CoreCLR solves this by having a set of suppressed columns that are never updated by deltas. (CoreCLR's model is to directly mutate the tables of the baseline image). In Mono we can eventually do the same thing by writing the value from the previous generation into the current delta's row. But right now since we don't allow parameter modifications, and the only column on a Method table that we allow to be modified is the RVA - which we look up specially - we can just always return the baseline image row for the method table.
Fixes #57643