| commit | 32626b418093f755971bca03911ef1e330bb3b9a | [log] [tgz] |
|---|---|---|
| author | Nikita Popov <npopov@redhat.com> | Wed Mar 20 10:59:45 2024 +0100 |
| committer | Copybara-Service <copybara-worker@google.com> | Wed Mar 20 03:09:40 2024 -0700 |
| tree | f8733333872fe588a6f1c836741a0c2ce94019c0 | |
| parent | 8c26472322d2157bef5ce295ba3dbc8e0bf6f187 [diff] |
[IR] Change representation of getelementptr inrange (#84341) As part of the migration to ptradd (https://discourse.llvm.org/t/rfc-replacing-getelementptr-with-ptradd/68699), we need to change the representation of the `inrange` attribute, which is used for vtable splitting. Currently, inrange is specified as follows: ``` getelementptr inbounds ({ [4 x ptr], [4 x ptr] }, ptr @vt, i64 0, inrange i32 1, i64 2) ``` The `inrange` is placed on a GEP index, and all accesses must be "in range" of that index. The new representation is as follows: ``` getelementptr inbounds inrange(-16, 16) ({ [4 x ptr], [4 x ptr] }, ptr @vt, i64 0, i32 1, i64 2) ``` This specifies which offsets are "in range" of the GEP result. The new representation will continue working when canonicalizing to ptradd representation: ``` getelementptr inbounds inrange(-16, 16) (i8, ptr @vt, i64 48) ``` The inrange offsets are relative to the return value of the GEP. An alternative design could make them relative to the source pointer instead. The result-relative format was chosen on the off-chance that we want to extend support to non-constant GEPs in the future, in which case this variant is more expressive. This implementation "upgrades" the old inrange representation in bitcode by simply dropping it. This is a very niche feature, and I don't think trying to upgrade it is worthwhile. Let me know if you disagree. GitOrigin-RevId: 0f46e31cfbf415fcd3d3ce121bef94e92c6ccfc8
This directory and its subdirectories contain source code for the LLVM Linker, a modular cross platform linker which is built as part of the LLVM compiler infrastructure project.
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In order to make sure various developers can evaluate patches over the same tests, we create a collection of self contained programs.
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