[Git][ghc/ghc][wip/T22849] 12 commits: nativeGen: Disable asm-shortcutting on Darwin

Simon Peyton Jones (@simonpj) gitlab at gitlab.haskell.org
Tue Jan 31 08:56:51 UTC 2023



Simon Peyton Jones pushed to branch wip/T22849 at Glasgow Haskell Compiler / GHC


Commits:
8bed166b by Ben Gamari at 2023-01-30T05:06:26-05:00
nativeGen: Disable asm-shortcutting on Darwin

Asm-shortcutting may produce relative references to symbols defined in
other compilation units. This is not something that MachO relocations
support (see #21972). For this reason we disable the optimisation on
Darwin. We do so without a warning since this flag is enabled by `-O2`.

Another way to address this issue would be to rather implement a
PLT-relocatable jump-table strategy. However, this would only benefit
Darwin and does not seem worth the effort.

Closes #21972.

- - - - -
da468391 by Cheng Shao at 2023-01-30T05:07:03-05:00
compiler: fix data section alignment in the wasm NCG

Previously we tried to lower the alignment requirement as far as
possible, based on the section kind inferred from the CLabel. For info
tables, .p2align 1 was applied given the GC should only need the
lowest bit to tag forwarding pointers. But this would lead to
unaligned loads/stores, which has a performance penalty even if the
wasm spec permits it. Furthermore, the test suite has shown memory
corruption in a few cases when compacting gc is used.

This patch takes a more conservative approach: all data sections
except C strings align to word size.

- - - - -
08ba8720 by Andreas Klebinger at 2023-01-30T21:18:45-05:00
ghc-the-library: Retain cafs in both static in dynamic builds.

We use keepCAFsForGHCi.c to force -fkeep-cafs behaviour by using a
__attribute__((constructor)) function.

This broke for static builds where the linker discarded the object file
since it was not reverenced from any exported code. We fix this by
asserting that the flag is enabled using a function in the same module
as the constructor. Which causes the object file to be retained by the
linker, which in turn causes the constructor the be run in static builds.

This changes nothing for dynamic builds using the ghc library. But causes
static to also retain CAFs (as we expect them to).

Fixes #22417.

-------------------------
Metric Decrease:
    T21839r
-------------------------

- - - - -
20598ef6 by Ryan Scott at 2023-01-30T21:19:20-05:00
Handle `type data` properly in tyThingParent_maybe

Unlike most other data constructors, data constructors declared with `type data`
are represented in `TyThing`s as `ATyCon` rather than `ADataCon`. The `ATyCon`
case in `tyThingParent_maybe` previously did not consider the possibility of
the underlying `TyCon` being a promoted data constructor, which led to the
oddities observed in #22817. This patch adds a dedicated special case in
`tyThingParent_maybe`'s `ATyCon` case for `type data` data constructors to fix
these oddities.

Fixes #22817.

- - - - -
2f145052 by Ryan Scott at 2023-01-30T21:19:56-05:00
Fix two bugs in TypeData TH reification

This patch fixes two issues in the way that `type data` declarations were
reified with Template Haskell:

* `type data` data constructors are now properly reified using `DataConI`.
  This is accomplished with a special case in `reifyTyCon`. Fixes #22818.

* `type data` type constructors are now reified in `reifyTyCon` using
  `TypeDataD` instead of `DataD`. Fixes #22819.

- - - - -
d0f34f25 by Simon Peyton Jones at 2023-01-30T21:20:35-05:00
Take account of loop breakers in specLookupRule

The key change is that in GHC.Core.Opt.Specialise.specLookupRule
we were using realIdUnfolding, which ignores the loop-breaker
flag.  When given a loop breaker, rule matching therefore
looped infinitely -- #22802.

In fixing this I refactored a bit.

* Define GHC.Core.InScopeEnv as a data type, and use it.
  (Previously it was a pair: hard to grep for.)

* Put several functions returning an IdUnfoldingFun into
  GHC.Types.Id, namely
     idUnfolding
     alwaysActiveUnfoldingFun,
     whenActiveUnfoldingFun,
     noUnfoldingFun
  and use them.  (The are all loop-breaker aware.)

- - - - -
de963cb6 by Matthew Pickering at 2023-01-30T21:21:11-05:00
ci: Remove FreeBSD job from release pipelines

We no longer attempt to build or distribute this release

- - - - -
f26d27ec by Matthew Pickering at 2023-01-30T21:21:11-05:00
rel_eng: Add check to make sure that release jobs are downloaded by fetch-gitlab

This check makes sure that if a job is a prefixed by "release-" then the
script downloads it and understands how to map the job name to the
platform.

- - - - -
7619c0b4 by Matthew Pickering at 2023-01-30T21:21:11-05:00
rel_eng: Fix the name of the ubuntu-* jobs

These were not uploaded for alpha1

Fixes #22844

- - - - -
68eb8877 by Matthew Pickering at 2023-01-30T21:21:11-05:00
gen_ci: Only consider release jobs for job metadata

In particular we do not have a release job for FreeBSD so the generation
of the platform mapping was failing.

- - - - -
b69461a0 by Jason Shipman at 2023-01-30T21:21:50-05:00
User's guide: Clarify overlapping instance candidate elimination

This commit updates the user's guide section on overlapping instance candidate
elimination to use "or" verbiage instead of "either/or" in regards to the
current pair of candidates' being overlappable or overlapping. "Either IX is
overlappable, or IY is overlapping" can cause confusion as it suggests "Either
IX is overlappable, or IY is overlapping, but not both".

This was initially discussed on this Discourse topic:

https://discourse.haskell.org/t/clarification-on-overlapping-instance-candidate-elimination/5677

- - - - -
dcce649e by Simon Peyton Jones at 2023-01-31T08:57:42+00:00
Treat existentials correctly in dubiousDataConInstArgTys

Consider (#22849)

 data T a where
   MkT :: forall k (t::k->*) (ix::k). t ix -> T @k a

Then dubiousDataConInstArgTys MkT [Type, Foo] should return
        [Foo (ix::Type)]
NOT     [Foo (ix::k)]

A bit of an obscure case, but it's an outright bug, and the fix is easy.

- - - - -


30 changed files:

- .gitlab-ci.yml
- .gitlab/gen_ci.hs
- .gitlab/jobs.yaml
- .gitlab/rel_eng/fetch-gitlab-artifacts/fetch_gitlab.py
- compiler/GHC.hs
- compiler/GHC/CmmToAsm.hs
- compiler/GHC/CmmToAsm/Wasm/FromCmm.hs
- compiler/GHC/Core.hs
- compiler/GHC/Core/Opt/ConstantFold.hs
- compiler/GHC/Core/Opt/Simplify/Utils.hs
- compiler/GHC/Core/Opt/Specialise.hs
- compiler/GHC/Core/Opt/WorkWrap/Utils.hs
- compiler/GHC/Core/Rules.hs
- compiler/GHC/Core/SimpleOpt.hs
- compiler/GHC/HsToCore/Pmc/Solver.hs
- compiler/GHC/Rename/Module.hs
- compiler/GHC/Tc/Gen/Splice.hs
- compiler/GHC/Types/Id.hs
- compiler/GHC/Types/Id/Info.hs
- compiler/GHC/Types/TyThing.hs
- compiler/cbits/keepCAFsForGHCi.c
- docs/users_guide/exts/instances.rst
- docs/users_guide/using-optimisation.rst
- testsuite/tests/ghci/T16392/T16392.script
- + testsuite/tests/ghci/scripts/T22817.hs
- + testsuite/tests/ghci/scripts/T22817.script
- + testsuite/tests/ghci/scripts/T22817.stdout
- testsuite/tests/ghci/scripts/all.T
- + testsuite/tests/simplCore/should_compile/T22802.hs
- + testsuite/tests/simplCore/should_compile/T22849.hs


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/6798170047729db66ad4d78261c2a4ba1c4f40ea...dcce649e868a8ad7d73968cf121762886b0c1564

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/6798170047729db66ad4d78261c2a4ba1c4f40ea...dcce649e868a8ad7d73968cf121762886b0c1564
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