[Git][ghc/ghc][wip/nonmoving-fixes] 51 commits: Hadrian: fix detection of ghc-pkg for cross-compilers

Ben Gamari gitlab at gitlab.haskell.org
Thu Dec 10 04:27:45 UTC 2020



Ben Gamari pushed to branch wip/nonmoving-fixes at Glasgow Haskell Compiler / GHC


Commits:
75fc1ed5 by Sylvain Henry at 2020-11-28T15:40:23-05:00
Hadrian: fix detection of ghc-pkg for cross-compilers

- - - - -
7cb5df96 by Sylvain Henry at 2020-11-28T15:40:23-05:00
hadrian: fix ghc-pkg uses (#17601)

Make sure ghc-pkg doesn't read the compiler "settings" file by passing
--no-user-package-db.

- - - - -
e3fd4226 by Ben Gamari at 2020-11-28T15:40:23-05:00
gitlab-ci: Introduce a nightly cross-compilation job

This adds a job to test cross-compilation from x86-64 to AArch64 with
Hadrian.

Fixes #18234

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698d3d96 by Ben Gamari at 2020-11-28T15:41:00-05:00
gitlab-ci: Only deploy GitLab Pages in ghc/ghc>

The deployments are quite large and yet are currently only served for
the ghc/ghc> project.

- - - - -
625726f9 by David Eichmann at 2020-11-28T15:41:37-05:00
ghc-heap: partial TSO/STACK decoding

Co-authored-by: Sven Tennie <sven.tennie at gmail.com>
Co-authored-by: Matthew Pickering <matthewtpickering at gmail.com>
Co-authored-by: Ben Gamari <bgamari.foss at gmail.com>

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22ea9c29 by Andreas Klebinger at 2020-11-28T15:42:13-05:00
Small optimization to CmmSink.

Inside `regsUsedIn` we can avoid some thunks by specializing the
recursion. In particular we avoid the thunk for `(f e z)` in the
MachOp/Load branches, where we know this will evaluate to z.

Reduces allocations for T3294 by ~1%.

- - - - -
bba42c62 by John Ericson at 2020-11-28T15:42:49-05:00
Make primop handler indentation more consistent

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c82bc8e9 by John Ericson at 2020-11-28T15:42:49-05:00
Cleanup some primop constructor names

Harmonize the internal (big sum type) names of the native vs fixed-sized
number primops a bit. (Mainly by renaming the former.)

No user-facing names are changed.

- - - - -
ae14f160 by Ben Gamari at 2020-11-28T15:43:25-05:00
testsuite: Mark T14702 as fragile on Windows

Due to #18953.

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1bc104b0 by Ben Gamari at 2020-11-29T15:33:18-05:00
withTimings: Emit allocations counter

This will allow us to back out the allocations per compiler pass from
the eventlog. Note that we dump the allocation counter rather than the
difference since this will allow us to determine how much work is done
*between* `withTiming` blocks.

- - - - -
e992ea84 by GHC GitLab CI at 2020-11-29T15:33:54-05:00
ThreadPaused: Don't zero slop until free vars are pushed

When threadPaused blackholes a thunk it calls `OVERWRITING_CLOSURE` to
zero the slop for the benefit of the sanity checker. Previously this was
done *before* pushing the thunk's free variables to the update
remembered set. Consequently we would pull zero'd pointers to the update
remembered set.

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e82cd140 by GHC GitLab CI at 2020-11-29T15:33:54-05:00
nonmoving: Fix regression from TSAN work

The TSAN rework (specifically aad1f803) introduced a subtle regression
in GC.c, swapping `g0` in place of `gen`. Whoops!

Fixes #18997.

- - - - -
35a5207e by GHC GitLab CI at 2020-11-29T15:33:54-05:00
rts/Messages: Add missing write barrier in THROWTO message update

After a THROWTO message has been handle the message closure is
overwritten by a NULL message. We must ensure that the original
closure's pointers continue to be visible to the nonmoving GC.

- - - - -
0120829f by GHC GitLab CI at 2020-11-29T15:33:54-05:00
nonmoving: Add missing write barrier in shrinkSmallByteArray

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8a4d8fb6 by GHC GitLab CI at 2020-11-29T15:33:54-05:00
Updates: Don't zero slop until closure has been pushed

Ensure that the the free variables have been pushed to the update
remembered set before we zero the slop.

- - - - -
2793cfdc by GHC GitLab CI at 2020-11-29T15:33:54-05:00
OSThreads: Fix error code checking

pthread_join returns its error code and apparently doesn't set errno.

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e391a16f by GHC GitLab CI at 2020-11-29T15:33:54-05:00
nonmoving: Don't join to mark_thread on shutdown

The mark thread is not joinable as we detach from it on creation.

- - - - -
60d088ab by Ben Gamari at 2020-11-29T15:33:54-05:00
nonmoving: Add reference to Ueno 2016

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3aa60362 by GHC GitLab CI at 2020-11-29T15:33:54-05:00
nonmoving: Ensure that evacuated large objects are marked

See Note [Non-moving GC: Marking evacuated objects].

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8d304a99 by Ben Gamari at 2020-11-30T10:15:22-05:00
rts/m32: Refactor handling of allocator seeding

Previously, in an attempt to reduce fragmentation, each new allocator
would map a region of M32_MAX_PAGES fresh pages to seed itself. However,
this ends up being extremely wasteful since it turns out that we often
use fewer than this.  Consequently, these pages end up getting freed
which, ends up fragmenting our address space more than than we would
have if we had naively allocated pages on-demand.

Here we refactor m32 to avoid this waste while achieving the
fragmentation mitigation previously desired. In particular, we move all
page allocation into the global m32_alloc_page, which will pull a page
from the free page pool. If the free page pool is empty we then refill
it by allocating a region of M32_MAP_PAGES and adding them to the pool.

Furthermore, we do away with the initial seeding entirely. That is, the
allocator starts with no active pages: pages are rather allocated on an
as-needed basis.

On the whole this ends up being a pleasingly simple change,
simultaneously making m32 more efficient, more robust, and simpler.

Fixes #18980.

- - - - -
b6629289 by Ben Gamari at 2020-11-30T10:15:58-05:00
rts: Use CHECK instead of assert

Use the GHC wrappers instead of <assert.h>.

- - - - -
9f4efa6a by Ben Gamari at 2020-11-30T10:15:58-05:00
rts/linker: Replace some ASSERTs with CHECK

In the past some people have confused ASSERT, which is for checking
internal invariants, which CHECK, which should be used when checking
things that might fail due to bad input (and therefore should be enabled
even in the release compiler). Change some of these cases in the linker
to use CHECK.

- - - - -
0f8a4655 by Ryan Scott at 2020-11-30T10:16:34-05:00
Allow deploy:pages job to fail

See #18973.

- - - - -
49ebe369 by chessai at 2020-11-30T19:47:40-05:00
Optimisations in Data.Foldable (T17867)

This PR concerns the following functions from `Data.Foldable`:
* minimum
* maximum
* sum
* product
* minimumBy
* maximumBy

- Default implementations of these functions now use `foldl'` or `foldMap'`.
- All have been marked with INLINEABLE to make room for further optimisations.

- - - - -
4d79ef65 by chessai at 2020-11-30T19:47:40-05:00
Apply suggestion to libraries/base/Data/Foldable.hs
- - - - -
6af074ce by chessai at 2020-11-30T19:47:40-05:00
Apply suggestion to libraries/base/Data/Foldable.hs
- - - - -
ab334262 by Viktor Dukhovni at 2020-11-30T19:48:17-05:00
dirty MVAR after mutating TSO queue head

While the original head and tail of the TSO queue may be in the same
generation as the MVAR, interior elements of the queue could be younger
after a GC run and may then be exposed by putMVar operation that updates
the queue head.

Resolves #18919

- - - - -
5eb163f3 by Ben Gamari at 2020-11-30T19:48:53-05:00
rts/linker: Don't allow shared libraries to be loaded multiple times

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490aa14d by Ben Gamari at 2020-11-30T19:48:53-05:00
rts/linker: Initialise CCSs from native shared objects

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6ac3db5f by Ben Gamari at 2020-11-30T19:48:53-05:00
rts/linker: Move shared library loading logic into Elf.c

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b6698d73 by GHC GitLab CI at 2020-11-30T19:48:53-05:00
rts/linker: Don't declare dynamic objects with image_mapped

This previously resulted in warnings due to spurious unmap failures.

- - - - -
b94a65af by jneira at 2020-11-30T19:49:31-05:00
Include tried paths in findToolDir error

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72a87fbc by Richard Eisenberg at 2020-12-01T19:57:41-05:00
Move core flattening algorithm to Core.Unify

This sets the stage for a later change, where this
algorithm will be needed from GHC.Core.InstEnv.

This commit also splits GHC.Core.Map into
GHC.Core.Map.Type and GHC.Core.Map.Expr,
in order to avoid module import cycles
with GHC.Core.

- - - - -
0dd45d0a by Richard Eisenberg at 2020-12-01T19:57:41-05:00
Bump the # of commits searched for perf baseline

The previous value of 75 meant that a feature branch with
more than 75 commits would get spurious CI passes.

This affects #18692, but does not fix that ticket, because
if a baseline cannot be found, we should fail, not succeed.

- - - - -
8bb52d91 by Richard Eisenberg at 2020-12-01T19:57:41-05:00
Remove flattening variables

This patch redesigns the flattener to simplify type family applications
directly instead of using flattening meta-variables and skolems. The key new
innovation is the CanEqLHS type and the new CEqCan constraint (Ct). A CanEqLHS
is either a type variable or exactly-saturated type family application; either
can now be rewritten using a CEqCan constraint in the inert set.

Because the flattener no longer reduces all type family applications to
variables, there was some performance degradation if a lengthy type family
application is now flattened over and over (not making progress). To
compensate, this patch contains some extra optimizations in the flattener,
leading to a number of performance improvements.

Close #18875.
Close #18910.

There are many extra parts of the compiler that had to be affected in writing
this patch:

* The family-application cache (formerly the flat-cache) sometimes stores
  coercions built from Given inerts. When these inerts get kicked out, we must
  kick out from the cache as well. (This was, I believe, true previously, but
  somehow never caused trouble.) Kicking out from the cache requires adding a
  filterTM function to TrieMap.

* This patch obviates the need to distinguish "blocking" coercion holes from
  non-blocking ones (which, previously, arose from CFunEqCans). There is thus
  some simplification around coercion holes.

* Extra commentary throughout parts of the code I read through, to preserve
  the knowledge I gained while working.

* A change in the pure unifier around unifying skolems with other types.
  Unifying a skolem now leads to SurelyApart, not MaybeApart, as documented
  in Note [Binding when looking up instances] in GHC.Core.InstEnv.

* Some more use of MCoercion where appropriate.

* Previously, class-instance lookup automatically noticed that e.g. C Int was
  a "unifier" to a target [W] C (F Bool), because the F Bool was flattened to
  a variable. Now, a little more care must be taken around checking for
  unifying instances.

* Previously, tcSplitTyConApp_maybe would split (Eq a => a). This is silly,
  because (=>) is not a tycon in Haskell. Fixed now, but there are some
  knock-on changes in e.g. TrieMap code and in the canonicaliser.

* New function anyFreeVarsOf{Type,Co} to check whether a free variable
  satisfies a certain predicate.

* Type synonyms now remember whether or not they are "forgetful"; a forgetful
  synonym drops at least one argument. This is useful when flattening; see
  flattenView.

* The pattern-match completeness checker invokes the solver. This invocation
  might need to look through newtypes when checking representational equality.
  Thus, the desugarer needs to keep track of the in-scope variables to know
  what newtype constructors are in scope. I bet this bug was around before but
  never noticed.

* Extra-constraints wildcards are no longer simplified before printing.
  See Note [Do not simplify ConstraintHoles] in GHC.Tc.Solver.

* Whether or not there are Given equalities has become slightly subtler.
  See the new HasGivenEqs datatype.

* Note [Type variable cycles in Givens] in GHC.Tc.Solver.Canonical
  explains a significant new wrinkle in the new approach.

* See Note [What might match later?] in GHC.Tc.Solver.Interact, which
  explains the fix to #18910.

* The inert_count field of InertCans wasn't actually used, so I removed
  it.

Though I (Richard) did the implementation, Simon PJ was very involved
in design and review.

This updates the Haddock submodule to avoid #18932 by adding
a type signature.

-------------------------
Metric Decrease:
    T12227
    T5030
    T9872a
    T9872b
    T9872c
Metric Increase:
    T9872d
-------------------------

- - - - -
d66660ba by Richard Eisenberg at 2020-12-01T19:57:41-05:00
Rename the flattener to become the rewriter.

Now that flattening doesn't produce flattening variables,
it's not really flattening anything: it's rewriting. This
change also means that the rewriter can no longer be confused
the core flattener (in GHC.Core.Unify), which is sometimes used
during type-checking.

- - - - -
add0aeae by Ben Gamari at 2020-12-01T19:58:17-05:00
rts: Introduce mmapAnonForLinker

Previously most of the uses of mmapForLinker were mapping anonymous
memory, resulting in a great deal of unnecessary repetition. Factor this
out into a new helper.

Also fixes a few places where error checking was missing or suboptimal.

- - - - -
97d71646 by Ben Gamari at 2020-12-01T19:58:17-05:00
rts/linker: Introduce munmapForLinker

Consolidates munmap calls to ensure consistent error handling.

- - - - -
d8872af0 by Ben Gamari at 2020-12-01T19:58:18-05:00
rts/Linker: Introduce Windows implementations for mmapForLinker, et al.

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c35d0e03 by Ben Gamari at 2020-12-01T19:58:18-05:00
rts/m32: Introduce NEEDS_M32 macro

Instead of relying on RTS_LINKER_USE_MMAP

- - - - -
41c64eb5 by Ben Gamari at 2020-12-01T19:58:18-05:00
rts/linker: Use m32 to allocate symbol extras in PEi386

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e0b08c5f by Ben Gamari at 2020-12-03T13:01:47-05:00
gitlab-ci: Fix copy-paste error

Also be more consistent in quoting.

- - - - -
33ec3a06 by Ben Gamari at 2020-12-03T23:11:31-05:00
gitlab-ci: Run linters through ci.sh

Ensuring that the right toolchain is used.

- - - - -
4a437bc1 by Shayne Fletcher at 2020-12-05T09:06:38-05:00
Fix bad span calculations of post qualified imports

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8fac4b93 by Ben Gamari at 2020-12-05T09:07:13-05:00
testsuite: Add a test for #18923

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62ed6957 by Simon Peyton Jones at 2020-12-08T15:31:41-05:00
Fix kind inference for data types. Again.

This patch fixes several aspects of kind inference for data type
declarations, especially data /instance/ declarations

Specifically

1. In kcConDecls/kcConDecl make it clear that the tc_res_kind argument
   is only used in the H98 case; and in that case there is no result
   kind signature; and hence no need for the disgusting splitPiTys in
   kcConDecls (now thankfully gone).

   The GADT case is a bit different to before, and much nicer.
   This is what fixes #18891.

   See Note [kcConDecls: kind-checking data type decls]

2. Do not look at the constructor decls of a data/newtype instance
   in tcDataFamInstanceHeader. See GHC.Tc.TyCl.Instance
   Note [Kind inference for data family instances].  This was a
   new realisation that arose when doing (1)

   This causes a few knock-on effects in the tests suite, because
   we require more information than before in the instance /header/.

   New user-manual material about this in "Kind inference in data type
   declarations" and "Kind inference for data/newtype instance
   declarations".

3. Minor improvement in kcTyClDecl, combining GADT and H98 cases

4. Fix #14111 and #8707 by allowing the header of a data instance
   to affect kind inferece for the the data constructor signatures;
   as described at length in Note [GADT return types] in GHC.Tc.TyCl

   This led to a modest refactoring of the arguments (and argument
   order) of tcConDecl/tcConDecls.

5. Fix #19000 by inverting the sense of the test in new_locs
   in GHC.Tc.Solver.Canonical.canDecomposableTyConAppOK.

- - - - -
0abe3ddf by Adam Sandberg Ericsson at 2020-12-08T15:32:19-05:00
hadrian: build the _l and _thr_l rts flavours in the develN flavours

The ghc binary requires the eventlog rts since
fc644b1a643128041cfec25db84e417851e28bab

- - - - -
a8a80e05 by Ben Gamari at 2020-12-09T19:25:41-05:00
users guide: Fix syntax errors

Fixes errors introduced by 3a55b3a2574f913d046f3a6f82db48d7f6df32e3.

- - - - -
af3300fb by Ben Gamari at 2020-12-09T19:25:41-05:00
users guide: Describe GC lifecycle events

Every time I am asked about how to interpret these events I need to
figure it out from scratch. It's well past time that the users guide
properly documents these.

- - - - -
c57baeb7 by Ben Gamari at 2020-12-09T23:25:30-05:00
nonmoving: Fix small CPP bug

Previously an incorrect semicolon meant that we would fail to call
busy_wait_nop when spinning.

- - - - -
82b6b3a6 by Ben Gamari at 2020-12-09T23:25:30-05:00
nonmoving: Don't push objects during deadlock detect GC

Previously we would push large objects and compact regions to the mark
queue during the deadlock detect GC, resulting in failure to detect
deadlocks.

- - - - -


28 changed files:

- .gitlab-ci.yml
- .gitlab/ci.sh
- compiler/GHC/Builtin/primops.txt.pp
- compiler/GHC/ByteCode/Types.hs
- compiler/GHC/Cmm/CommonBlockElim.hs
- compiler/GHC/Cmm/Dataflow/Label.hs
- compiler/GHC/Cmm/Sink.hs
- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Core/Coercion.hs-boot
- compiler/GHC/Core/Coercion/Axiom.hs
- compiler/GHC/Core/Coercion/Opt.hs
- compiler/GHC/Core/FamInstEnv.hs
- compiler/GHC/Core/InstEnv.hs
- + compiler/GHC/Core/Map/Expr.hs
- compiler/GHC/Core/Map.hs → compiler/GHC/Core/Map/Type.hs
- compiler/GHC/Core/Opt/CSE.hs
- compiler/GHC/Core/Opt/ConstantFold.hs
- compiler/GHC/Core/TyCo/FVs.hs
- compiler/GHC/Core/TyCo/Rep.hs
- compiler/GHC/Core/TyCon.hs
- compiler/GHC/Core/TyCon/Env.hs
- compiler/GHC/Core/Type.hs
- compiler/GHC/Core/Unify.hs
- compiler/GHC/Data/Bag.hs
- compiler/GHC/Data/Maybe.hs
- compiler/GHC/Data/TrieMap.hs
- compiler/GHC/Driver/Flags.hs
- compiler/GHC/Driver/Session.hs


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/b416189e4004506b89f06f147be37e76f4cd507f...82b6b3a6d41cc02ba6232e53ee7e9cd00f5a2a82

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View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/b416189e4004506b89f06f147be37e76f4cd507f...82b6b3a6d41cc02ba6232e53ee7e9cd00f5a2a82
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