[RuntimeDyld][ELF] Fix unwanted sign extension. #94482
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Casting the result of `Section.getAddressWithOffset()` goes wrong if we are on a 32-bit platform whose addresses are regarded as signed; in that case, just doing ``` (uint64_t)Section.getAddressWithOffset(...) ``` or ``` reinterpret_cast<uint64_t>(Section.getAddressWithOffset(...)) ``` will result in sign-extension. We use these expressions when constructing branch stubs, which is before we know the final load address, so we can just switch to the `Section.getLoadAddressWithOffset(...)` method instead. Doing that is also more consistent, since when calculating relative offsets for relocations, we use the load address anyway, so the code currently only works because `Section.Address` is equal to `Section.LoadAddress` at this point. Fixes llvm#94478.
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@mgorny Could you try this fix and check that it works for you? |
mgorny
approved these changes
Jun 5, 2024
lhames
approved these changes
Jun 6, 2024
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Casting the result of
Section.getAddressWithOffset()goes wrong if we are on a 32-bit platform whose addresses are regarded as signed; in that case, just doingor
will result in sign-extension.
We use these expressions when constructing branch stubs, which is before we know the final load address, so we can just switch to the
Section.getLoadAddressWithOffset(...)method instead.Doing that is also more consistent, since when calculating relative offsets for relocations, we use the load address anyway, so the code currently only works because
Section.Addressis equal toSection.LoadAddressat this point.Fixes #94478.