We used to have MIN_UPD_SIZE macro that describes the minimum reserved
size for thunks, so that the thunk can be overwritten in place as
indirections or blackholes. However, this macro has not been actually
defined or used anywhere since a long time ago; StgThunkHeader already
reserves a padding word for this purpose. Hence this patch which drops
stale mentions of MIN_UPD_SIZE.

(cherry picked from commit c1e3719c)
(cherry picked from commit 8d9efe4d)

We found that speculative evaluation can increase the amount of
allocations in some circumstances. This patch adds new flags for
selectively disabling speculative evaluation, allowing us to
test the effect of the optimization.

The new flags are:

  -fspec-eval
     globally enable speculative evaluation

  -fspec-eval-dictfun
     enable speculative evaluation for dictionary functions (no effect
     if speculative evaluation is globally disabled)

The new flags are on by default for all optimisation levels.

See #25284

(cherry picked from commit 23099752)

ARATA Mizuki authored 3 months ago and Luite Stegeman committed 3 months ago

With a recent LLVM, `llc -version` emits the version on the first line
if the vendor is set.  It emits the version on the second line
otherwise.

Therefore, we need to check the both lines to detect the version.

GHC now emits a warning if it fails to detect the LLVM version,
so we can notice if the output of `llc -version` changes in the future.

Also, the warning for using LLVM < 10 on s390x is removed, because
we assume LLVM >= 13 now.

This fixes the definition of __GLASGOW_HASKELL_LLVM__ macro.

Fixes #25606

(cherry picked from commit a928c326)

Ben Gamari authored 4 months ago and Luite Stegeman committed 3 months ago

Previously the maximum number of capabilities supported by the RTS was
statically capped at 256. However, this bound is uncomfortably low given
the size of today's machine.

While supporting unbounded, fully-dynamic adjustment would be nice, it
is complex and so instead we do something simpler: Probe the logical
core count at RTS startup and use this as the static bound for the rest
of our execution.

This should avoid users running into the capability limit on large
machines while avoiding wasting memory on a large capabilities array for
most users and keeping complexity at bay.

Addresses #25560.

(cherry picked from commit 71f050b7)

Ben Gamari authored 4 months ago and Luite Stegeman committed 3 months ago

Addresses #25560.

(cherry picked from commit 06265655)

mimi.vx authored 1 year ago and Luite Stegeman committed 3 months ago

Fixes ghc/ghc#23444

(cherry picked from commit 70526f5b)

Teo Camarasu authored 11 months ago and Zubin committed 9 months ago

(cherry picked from commit 06f7db40)

Metric Increase:
    MultiLayerModulesTH_Make

Metric Decrease:
    MultiLayerModulesTH_Make

This flag is known to result in unsound optimisations potentially resulting in
incorrect runtime behaviour (#24507).

(cherry picked from commit 4ae8d89e)

Teo Camarasu authored 1 year ago and Zubin committed 1 year ago

Resolves #24394

(cherry picked from commit 94ce031d)

Metric Decrease:
    MultiLayerModulesTH_Make

Document the permissibility introduced by
https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0170-unrestricted-overloadedlabels.rst

(cherry picked from commit c247b6be)

Metric Decrease:
    T13701

Metric Decrease:
    MultiComponentModules
    MultiComponentModulesRecomp
    MultiLayerModules
    MultiLayerModulesRecomp
    T10421
    T12150
    T12234
    T12425
    T13035
    T13701
    T13719
    T15164
    T16875
    T18140
    T18304
    T18698a
    T18698b
    T18923
    T20049
    T9198
    T9961
    hard_hole_fits
Metric Decrease 'compile_time/bytes allocated':
    T21839r
Metric Increase 'runtime/max_bytes_used':
    T21839r
Metric Increase 'runtime/peak_megabytes_allocated':
    T21839r

Finley McIlwaine authored 1 year ago and Zubin committed 1 year ago

The -fno-info-table-map-with-stack flag omits STACK info tables from the info
table map, and the -fno-info-table-map-with-fallback flag omits info tables
with defaulted source locations from the map. In a test on the Agda codebase
the build results were about 7% smaller when both of those types of tables
were omitted.

Adds a test that verifies that passing each combination of these flags
results in the correct output for -dipe-stats, which is disabled for the js
backend since profiling is not implemented.

This commit also refactors a lot of the logic around extracting info tables
from the Cmm results and building the info table map.

This commit also fixes some issues in the users guide rst source to fix
warnings that were noticed while debugging the documentation for these flags.

Fixes #23702

(cherry picked from commit 261c4acb)

Finley McIlwaine authored 1 year ago and Zubin committed 1 year ago

This is useful for seeing which info tables have information.

(cherry picked from commit cc52c358)

Gergő Érdi authored 1 year ago and Zubin committed 1 year ago

Based on @simonpj's draft and comments in !11117

(cherry picked from commit eaee4d29)

Ben Gamari authored 1 year ago and Zubin committed 1 year ago

The semantics of the `extlinks` attribute annoyingly changed in Sphinx
4. Reflect this in our configuration. See #22690.

Fixes #23807.

(cherry picked from commit 1726db3f)

Ben Gamari authored 1 year ago and Zubin committed 1 year ago

As noted in #23818, some old distributions (e.g. Debian 9) only include
`distutils` while newer distributions only include `packaging`.

Fixes #23818.

(cherry picked from commit d814bda9)

Dave Barton authored 1 year ago and Zubin committed 1 year ago

(cherry picked from commit 4457da2a)

Matthew Pickering authored 1 year ago and Zubin committed 1 year ago

Polymorphic specialisation has led to a number of hard to diagnose
incorrect runtime result bugs (see #23469, #23109, #21229, #23445) so
this commit introduces a flag `-fpolymorhphic-specialisation` which
allows users to turn on this experimental optimisation if they are
willing to buy into things going very wrong.

Ticket #23469

(cherry picked from commit 9f01d14b)

Matthew Pickering authored 2 years ago and Ben Gamari committed 1 year ago

* Generate docs/index.html to include the version of the ghc library

* This also fixes the packageVersions interpolations which were
  - Missing an interpolation for `LIBRARY_ghc_VERSION`
  - Double quoting the version so that "9.7" was being inserted.

Fixes #23121

(cherry picked from commit d7a768a4)

Chris Wendt authored 2 years ago and Ben Gamari committed 2 years ago

(cherry picked from commit c6e1f3cd)

Thanks to David Christiansen for noticing this.

Closes #23027.

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.

(cherry picked from commit 8bed166b)

Alexis King authored 2 years ago and Ben Gamari committed 2 years ago

This commit also adds a new -Dk RTS option to the debug RTS to assist
debugging continuation captures. Currently, the printed information is
quite minimal, but more can be added in the future if it proves to be
useful when debugging future issues.

fixes #23001

(cherry picked from commit e5794ede)

Fixes #23006

Cheng Shao authored 2 years ago and Matthew Pickering committed 2 years ago

Fixes #22658

(cherry picked from commit 631c6c72)

sheaf authored 2 years ago and Matthew Pickering committed 2 years ago

Commit aed1974e completely re-engineered the treatment of loopy
superclass dictionaries in instance declarations. Unfortunately,
it has the potential to break (albeit in a rather minor way) user code.

To alleviate migration concerns, this commit re-introduces the old
behaviour. Any reliance on this old behaviour triggers a warning,
controlled by `-Wloopy-superclass-solve`. The warning text explains
that GHC might produce bottoming evidence, and provides a migration
strategy.

This allows us to provide a graceful migration period, alerting users
when they are relying on this unsound behaviour.

Fixes #22912 #22891 #20666 #22894 #22905

(cherry picked from commit 9fb4ca89)

sheaf authored 2 years ago and Matthew Pickering committed 2 years ago

Commit cfc8e2e2 introduced a mechanism for handling of exceptions
that occur during Handle finalization, and 372cf730 set the default
handler to print out the error to stderr.

However, #21680 pointed out we might not want to set this by default,
as it might pollute users' terminals with unwanted information.
So, for the time being, the default handler discards the exception.

Fixes #21680

(cherry picked from commit 681e0e8c)

jeffrey young authored 2 years ago and Matthew Pickering committed 2 years ago

Follow up from #21078

(cherry picked from commit 08c0822c)