Qiskit / qiskit / 22872493867

88%

Build Type

push

github

Committed by web-flow

Commit Message

Store pointers within `PackedOperation` (#15553)

* Store pointers within `PackedOperation`

This sets up the internals of `PackedOperation` to store pointers
directly.  This allows us to track the provenance of the pointers using
Miri so we can validate that we're not invoking undefined behaviour in
Qiskit by making invalid reads.  It's fine to cast an integer into a
pointer for storage, provided we never _read_ from the pointer, and Miri
is capable of checking that we don't do that.

I don't have a good way to run the Miri tests of the 32-bit pointer form
(or, I guess, _any_ tests) at all right now, so it's hard to validate if
this works completely on that platform.  I mostly just wanted to
demonstrate the principle of it, though.

* Fix 32-bit build

This includes some silly oversights that really betray how I failed to
test the build before now.

I now tested the build by attempting cross-compiles to the
`i686-unknown-linux-gnu` target "triple" and
`armv7-unknown-linux-gnueabihf` triple:

```
rustup target add <triple>
cargo (build|check) --target <triple>
```

On x86 Linux, the Qiskit build mostly succeeds, but some inline assembly
in pulp 0.21.2 assumes x86-64 and so the build fails.  On ARMv7, the
compilation completes successfully but there is some linker failure I
was disinclined to debug.  On ARMv7 I was able to `cargo check`
completely successfully.  I wasn't able to run the test suite because of
the additional build failures, but I don't believe those to be related
to the patch.

(I used that specific ARMv7 triple because it's got Rust support at
Tier 2 with host tools and I have an old Raspberry Pi that would have
been able to run it.)

* Correct old comment reference to `PyGate`

Run Details

48 of 48 new or added lines in 1 file covered. (100.0%)

21 existing lines in 2 files now uncovered.

101148 of 115310 relevant lines covered (87.72%)

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