[Git][ghc/ghc][wip/underflow-lookups] 20 commits: Deal correctly with Given CallStack constraints

Matthew Pickering (@mpickering) gitlab at gitlab.haskell.org
Thu Feb 20 14:18:08 UTC 2025 


Matthew Pickering pushed to branch wip/underflow-lookups at Glasgow Haskell Compiler / GHC


Commits:
e22a14fc by Simon Peyton Jones at 2025-02-11T16:21:10+00:00
Deal correctly with Given CallStack constraints

As #25675 showed, the CallStack solving mechanism was failing
to account for Given CallStack constraints.

This small patch fixes it and improves the Notes.

Small improvement to GHCi debugger output in break011, break024,
which is discussed on the MR !13883

- - - - -
db3e810f by Simon Peyton Jones at 2025-02-12T09:12:30-05:00
Fix inlineBoringOk again

This MR fixes #25713, which turned out to be a consequence of not
completing #17182.

I think I have now gotten it right.  See the new
  Note [inlineBoringOk]

- - - - -
ef0e6cfc by Ben Gamari at 2025-02-17T19:20:09-05:00
testsuite: Mark T23071 and T2047 as fragile on FreeBSD

These inexplicably fail on FreeBSD on CI. Sadly I am unable to reproduce
this locally but regardless this is holding up Marge so I will mark them
as fragile for now.

Addresses #25751.

- - - - -
7596675e by Jens Petersen at 2025-02-18T08:53:08-05:00
hp2ps Utilities.c: include stdlib.h instead of extern malloc and realloc

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975d932c by Rodrigo Mesquita at 2025-02-18T08:53:45-05:00
Inline join points for rhs without free vars

While investigating #25170, we ran into a program (T16473) that allocated 67%
more because of a join point that failed to inline.

Note [Duplicating join points] explains why we want to be conservative
when inlining join points, using as an example a join point that
captures a free variable `f` that becomes available in the continuation
`blah` for further optimisations, as opposed to being lambda-abstracted.

However, when the RHS of the join point has no free variables and is
trivial, the same argument does not apply, and there's nothing to gain
from preserving it.

On the contrary, not inlining these trivial join points such as
    $j f x = K f x |> co
can be actively harmful as they prevent useful optimisations from firing
on the known constructor application. #25723 is such an example.

Therefore, we've extended `uncondInlineJoin` to allow duplicating such closed
trivial join points. See the updated Note [Duplicating join points] for
further details.

Additionally, merge the guards in uncondInlineJoin for point DJ3(b) anad DJ3(c) of
Note [Duplicating join points] to avoid an unnecessary traversal in the
call to `collectArgs`; it's also more uniform.

Co-authored-by: Simon Peyton Jones <simon.peytonjones at gmail.com>

Fixes #25723

- - - - -
78de1a55 by M Farkas-Dyck at 2025-02-18T08:54:31-05:00
Scrub some partiality in `GHC.Tc.Gen.Match`.

In particular, we construct a list of the same length as another list, then loop over both and panic if their lengths are unequal. We can avoid this.

- - - - -
1dfe9325 by M Farkas-Dyck at 2025-02-18T08:54:31-05:00
Make list of `ParStmtBlock` in `ParStmt` `NonEmpty`.

In the ParStmt constructor Language.Haskell.Syntax.Expr.StmtLR, the 2nd argument, the list of ParStmtBlocks, must be NonEmpty; make it so.

- - - - -
0e3575b5 by M Farkas-Dyck at 2025-02-18T08:54:31-05:00
GHC.Tc.Gen.Match: Added type signatures for `loop` functions.

- - - - -
c9ffcfee by sternenseemann at 2025-02-18T08:55:14-05:00
GHC: fix reference to function in Note [Target code interpreter]

As far as I could tell, setSessionDynFlags doesn't deal with hsc_interp.
Also added a backreference so this will be updated in the future.

- - - - -
ab77fc8c by sheaf at 2025-02-18T08:55:57-05:00
Account for skolem escape in mightEqualLater

This commit:

  1. Refactors checkTyEqRhs to allow it be called in pure contexts,
     which means it skips doing any on-the-fly promotion.
  2. Calls checkTyEqRhs in mightEqualLater to check whether it a
     MetaTv can unify with a RHS or whether that would cause e.g.
     skolem escape errors or concreteness errors.

Fixes #25744

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cb8a06a4 by Sylvain Henry at 2025-02-18T08:56:52-05:00
Remove a bunch of Makefiles from old build system

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e12d6b39 by M Farkas-Dyck at 2025-02-18T08:57:37-05:00
Totalize `GHC.HsToCore.Match.matchWrappers.initNablasGRHSs`.

Converting from `NonEmpty` to `[]` and back is totally needless.

- - - - -
cd2be3be by Matthew Pickering at 2025-02-18T08:58:14-05:00
interpreter: Always print uniques for BCO_NAME labels

In the previous commit I omitted to include the unique, which still
makes it very difficult to trace back where the BCO came from.

- - - - -
c4e112fc by Matthew Pickering at 2025-02-18T08:58:51-05:00
interpreter: Fix overflows and reentrancy in statistics calculation

1. Use unsigned long for counter, as they can easily overflow if you are
   running a long benchmark.
2. Make interp_shutdown reentrant by copying the command frequency table
   into an array.

Fixes #25756

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70ac6222 by M Farkas-Dyck at 2025-02-18T14:22:06-08:00
Use `Foldable1` where appropriate, avoiding much needless panicking.

In some cases, where not readily feasible to modify code to use `NonEmpty`, merely use `expectNonEmpty` to make explicit we are panicking if we have an empty list.

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a3f0a506 by Sylvain Henry at 2025-02-19T05:27:30-05:00
Testsuite: fix deprecation warning

> DeprecationWarning: 'count' is passed as positional argument

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ef5470a2 by Ben Gamari at 2025-02-19T16:30:53+00:00
Cmm/Parser: Add surface syntax for Mul2 MachOps

These are otherwise very hard to test in isolation.

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59b9307b by Cheng Shao at 2025-02-19T20:24:40-05:00
testsuite: fix InternalCounters test with +debug_ghc

The `InternalCounters` test case fails when ghc is built with
`+debug_ghc`. This patch skips it in that case and allows the
testsuite to pass for the `+debug_ghc` flavour transformer.

- - - - -
aa69187d by M Farkas-Dyck at 2025-02-19T20:25:31-05:00
Scrub a use of `head` in `GHC.Driver.Make.downsweep_imports.checkDuplicates`.

- - - - -
e8e4b534 by Matthew Pickering at 2025-02-20T14:17:32+00:00
interpreter: Fix underflow frame lookups

BCOs can be nested, resulting in nested BCO stack frames where the inner most
stack frame can refer to variables stored on earlier stack frames via the
PUSH_L instruction.

|---------|
|  BCO_1  | -<-┐
|---------|
 .........     |
|---------|    | PUSH_L <n>
|  BCO_N  | ->-┘
|---------|

Here BCO_N is syntactically nested within the code for BCO_1 and will result
in code that references the prior stack frame of BCO_1 for some of it's local
variables. If a stack overflow happens between the creation of the stack frame
for BCO_1 and BCO_N the RTS might move BCO_N to a new stack chunk while leaving
BCO_1 in place, invalidating a simple offset based reference to the outer stack
frames.
Therefore `ReadSpW` first performs a bounds check to ensure that accesses onto
the stack will succeed. If the target address would not be a valid location for
the current stack chunk then `slow_spw` function is called, which dereferences
the underflow frame to adjust the offset before performing the lookup.

               ┌->--x   |  CHK_1  |
|  CHK_2  |    |    |   |---------|
|---------|    |    └-> |  BCO_1  |
| UD_FLOW | -- x        |---------|
|---------|    |
| ......  |    |
|---------|    | PUSH_L <n>
|  BCO_ N | ->-┘
|---------|

Fixes #25750

- - - - -


110 changed files:

- compiler/GHC.hs
- compiler/GHC/Cmm/Dataflow/Label.hs
- compiler/GHC/Cmm/DebugBlock.hs
- compiler/GHC/Cmm/LayoutStack.hs
- compiler/GHC/Cmm/Parser.y
- compiler/GHC/CmmToAsm/Reg/Graph/Base.hs
- compiler/GHC/CmmToAsm/Reg/Graph/SpillClean.hs
- compiler/GHC/CmmToAsm/Reg/Graph/SpillCost.hs
- compiler/GHC/CmmToAsm/X86/CodeGen.hs
- compiler/GHC/Core.hs
- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/Opt/Arity.hs
- compiler/GHC/Core/Opt/CallArity.hs
- compiler/GHC/Core/Opt/OccurAnal.hs
- compiler/GHC/Core/Opt/SetLevels.hs
- compiler/GHC/Core/Opt/Simplify/Iteration.hs
- compiler/GHC/Core/Opt/Simplify/Utils.hs
- compiler/GHC/Core/Opt/SpecConstr.hs
- compiler/GHC/Core/Unfold.hs
- compiler/GHC/Core/Unfold/Make.hs
- compiler/GHC/Core/Utils.hs
- compiler/GHC/Data/Graph/Inductive/Graph.hs
- + compiler/GHC/Data/List.hs
- compiler/GHC/Data/List/NonEmpty.hs
- compiler/GHC/Data/Pair.hs
- compiler/GHC/Driver/Env.hs
- compiler/GHC/Driver/Make.hs
- compiler/GHC/Hs/Expr.hs
- compiler/GHC/Hs/Utils.hs
- compiler/GHC/HsToCore/ListComp.hs
- compiler/GHC/HsToCore/Match.hs
- compiler/GHC/HsToCore/Match/Literal.hs
- compiler/GHC/HsToCore/Pmc/Solver.hs
- compiler/GHC/HsToCore/Quote.hs
- compiler/GHC/HsToCore/Utils.hs
- compiler/GHC/Iface/Ext/Ast.hs
- compiler/GHC/JS/Ppr.hs
- compiler/GHC/Parser.y
- compiler/GHC/Parser/Annotation.hs
- compiler/GHC/Prelude/Basic.hs
- compiler/GHC/Rename/Expr.hs
- compiler/GHC/Rename/Utils.hs
- compiler/GHC/Stg/Lift/Analysis.hs
- compiler/GHC/StgToByteCode.hs
- compiler/GHC/StgToCmm/Layout.hs
- compiler/GHC/StgToCmm/Prim.hs
- compiler/GHC/StgToJS/Expr.hs
- compiler/GHC/Tc/Deriv/Functor.hs
- compiler/GHC/Tc/Deriv/Generate.hs
- compiler/GHC/Tc/Deriv/Generics.hs
- compiler/GHC/Tc/Errors/Ppr.hs
- compiler/GHC/Tc/Errors/Types.hs
- compiler/GHC/Tc/Gen/Bind.hs
- compiler/GHC/Tc/Gen/Default.hs
- compiler/GHC/Tc/Gen/Match.hs
- compiler/GHC/Tc/Solver/Default.hs
- compiler/GHC/Tc/Solver/Dict.hs
- compiler/GHC/Tc/Solver/InertSet.hs
- compiler/GHC/Tc/Solver/Monad.hs
- compiler/GHC/Tc/Solver/Solve.hs
- compiler/GHC/Tc/Solver/Types.hs
- compiler/GHC/Tc/Types/Evidence.hs
- compiler/GHC/Tc/Types/Origin.hs
- compiler/GHC/Tc/Utils/Unify.hs
- compiler/GHC/Tc/Zonk/Type.hs
- compiler/GHC/ThToHs.hs
- compiler/GHC/Types/Demand.hs
- compiler/GHC/Types/Error/Codes.hs
- compiler/GHC/Types/Name.hs
- compiler/GHC/Unit/Finder.hs
- compiler/GHC/Unit/Module/Graph.hs
- compiler/GHC/Utils/Misc.hs
- compiler/Language/Haskell/Syntax/Expr.hs
- compiler/ghc.cabal.in
- docs/users_guide/9.14.1-notes.rst
- rts/Interpreter.c
- testsuite/driver/testlib.py
- testsuite/tests/count-deps/CountDepsAst.stdout
- testsuite/tests/count-deps/CountDepsParser.stdout
- testsuite/tests/ghci.debugger/scripts/break011.stdout
- testsuite/tests/ghci.debugger/scripts/break024.stdout
- + testsuite/tests/perf/compiler/T25723.hs
- + testsuite/tests/perf/compiler/T25723.stdout
- testsuite/tests/perf/compiler/all.T
- testsuite/tests/primops/should_run/all.T
- + testsuite/tests/profiling/should_run/T25675.hs
- + testsuite/tests/profiling/should_run/T25675.stdout
- testsuite/tests/profiling/should_run/all.T
- testsuite/tests/rts/all.T
- testsuite/tests/simplCore/should_compile/T22375DataFamily.stderr
- testsuite/tests/simplCore/should_compile/T24229a.stderr
- testsuite/tests/simplCore/should_compile/T24229b.stderr
- + testsuite/tests/simplCore/should_compile/T25713.hs
- + testsuite/tests/simplCore/should_compile/T25713.stderr
- testsuite/tests/simplCore/should_compile/all.T
- + testsuite/tests/th/EmptyParStmt.hs
- + testsuite/tests/th/EmptyParStmt.stderr
- testsuite/tests/th/all.T
- + testsuite/tests/typecheck/should_compile/T25744.hs
- testsuite/tests/typecheck/should_compile/all.T
- − utils/deriveConstants/Makefile
- − utils/genprimopcode/Makefile
- − utils/ghc-pkg/Makefile
- − utils/hp2ps/Makefile
- utils/hp2ps/Utilities.c
- − utils/iserv/Makefile
- − utils/remote-iserv/Makefile
- − utils/runghc/Makefile
- − utils/unlit/Makefile


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/7094e270f4a8637ddb50713028d21a43e9dfde70...e8e4b534eb0b5a3792b2b291d84a912202b44049

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View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/7094e270f4a8637ddb50713028d21a43e9dfde70...e8e4b534eb0b5a3792b2b291d84a912202b44049
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