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Always set addlDelta to zero on x86 #79467

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SingleAccretion
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@SingleAccretion SingleAccretion commented Dec 9, 2022

As best as I am able to infer from reading the code, this value is only meant to be used for reporting relocations of RIP-relative addresses, which x86 doesn't have.

Fixes #79170.

No diffs are expected.

The value is used to compensate for the additional instruction bytes,
which should only be relevant for RIP-relative addressing, while x86
uses absolute addressing.
@dotnet-issue-labeler dotnet-issue-labeler bot added the area-CodeGen-coreclr CLR JIT compiler in src/coreclr/src/jit and related components such as SuperPMI label Dec 9, 2022
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Issue Details

As best as I am able to infer from reading the code, this value is meant to be used for reporting relocations of RIP-relative addresses, which x86 doesn't have.

Fixes #79170.

No diffs are expected.

Author: SingleAccretion
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area-CodeGen-coreclr

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SingleAccretion commented Dec 10, 2022

Failure is #79439.

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@SingleAccretion SingleAccretion marked this pull request as ready for review December 10, 2022 13:04
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This seems like a reasonable fix, but I wonder if we should consider this a crossgen2 bug.

I wrote a fix there that seems to work: #79627

This matches the behavior that the old ngen tool had: ignore addlDelta except for REL32 relocs, and the IMAGE_REL_BASED_DISP32 "pseudo-reloc" used here only maps to REL32 on x64; it maps to HIGHLOW on x86.

@BruceForstall BruceForstall merged commit ef903fd into dotnet:main Dec 14, 2022
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I wonder if we should consider this a crossgen2 bug

Indeed, that was the main question here. What made me prefer a fix in the Jit was that it is easier to understand: there is no computation of data on one side where the other is expected to explicitly ignore it for things to work properly.

@SingleAccretion SingleAccretion deleted the Fixing-Reloc-Deltas-Upstream branch December 15, 2022 17:10
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JIT.Regression\JitBlue\Runtime_31615\Runtime_31615\Runtime_31615 fails
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