-
fd64667d
by Vladislav Zavialov at 2025-05-20T03:25:08-04:00
Allow the 'data' keyword in import/export lists (#25899)
This patch introduces the 'data' namespace specifier in import and
export lists. The intended use is to import data constructors without
their parent type constructors, e.g.
import Data.Proxy as D (data Proxy)
type DP = D.Proxy -- promoted data constructor
Additionally, it is possible to use 'data' to explicitly qualify any
data constructors or terms, incl. operators and field selectors
import Prelude (Semigroup(data (<>)))
import Data.Function (data (&))
import Data.Monoid (data Dual, data getDual)
x = Dual "Hello" <> Dual "World" & getDual
The implementation mostly builds on top of the existing logic for the
'type' and 'pattern' namespace specifiers, plus there are a few tweaks
to how we generate suggestions in error messages.
-
acc86753
by Ben Gamari at 2025-05-20T03:25:51-04:00
compiler: Use field selectors when creating BCOs
This makes it easier to grep for these fields.
-
60a55fd7
by Ben Gamari at 2025-05-20T03:25:51-04:00
compiler: Clarify BCO size
Previously the semantics and size of StgBCO was a bit unclear.
Specifically, the `size` field was documented to contain the size of the
bitmap whereas it was actually the size of the closure *and* bitmap.
Additionally, it was not as clear as it could be that the bitmap was a
full StgLargeBitmap with its own `size` field.
-
ac9fb269
by Simon Peyton Jones at 2025-05-20T09:19:04-04:00
Track rewriter sets more accurately in constraint solving
This MR addresses #26003, by refactoring the arcane
intricacies of Note [Equalities with incompatible kinds].
NB: now retitled to
Note [Equalities with heterogeneous kinds].
and the main Note for this MR.
In particular:
* Abandon invariant (COERCION-HOLE) in Note [Unification preconditions] in
GHC.Tc.Utils.Unify.
* Abandon invariant (TyEq:CH)) in Note [Canonical equalities] in
GHC.Tc.Types.Constraint.
* Instead: add invariant (REWRITERS) to Note [Unification preconditions]:
unify only if the constraint has an empty rewriter set.
Implementation:
* In canEqCanLHSFinish_try_unification, skip trying unification if there is a
non-empty rewriter set.
* To do this, make sure the rewriter set is zonked; do so in selectNextWorkItem,
which also deals with prioritisation.
* When a coercion hole is filled, kick out inert equalities that have that hole
as a rewriter. It might now be unlocked and available to unify.
* Remove the ad-hoc `ch_hetero_kind` field of `CoercionHole`.
* In `selectNextWorkItem`, priorities equalities withan empty rewriter set.
* Defaulting: see (DE6) in Note [Defaulting equalities]
and Note [Limited defaulting in the ambiguity check]
* Concreteness checks: there is some extra faff to try to get decent
error messages when the FRR (representation-polymorphism) checks
fail. In partiular, add a "When unifying..." explanation when the
representation-polymorphism check arose from another constraint.
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86406f48
by Cheng Shao at 2025-05-20T09:19:47-04:00
rts: fix rts_clearMemory logic when sanity checks are enabled
This commit fixes an RTS assertion failure when invoking
rts_clearMemory with +RTS -DS. -DS implies -DZ which asserts that free
blocks contain 0xaa as the designated garbage value. Also adds the
sanity way to rts_clearMemory test to prevent future regression.
Closes #26011.
ChatGPT Codex automatically diagnosed the issue and proposed the
initial patch in a single shot, given a GHC checkout and the following
prompt:
---
Someone is reporting the following error when attempting to use `rts_clearMemory` with the RTS option `-DS`:
```
test.wasm: internal error: ASSERTION FAILED: file rts/sm/Storage.c, line 1216
(GHC version 9.12.2.20250327 for wasm32_unknown_wasi)
Please report this as a GHC bug: https://www.haskell.org/ghc/reportabug
```
What's the culprit? How do I look into this issue?
---
I manually reviewed & revised the patch, tested and submitted it.
-
7147370b
by Cheng Shao at 2025-05-20T17:22:19-04:00
compiler: do not allocate strings in bytecode assembler
This patch refactors the compiler to avoid allocating iserv buffers
for BCONPtrStr at assemble-time. Now BCONPtrStr ByteStrings are
recorded as a part of CompiledByteCode, and actual allocation only
happens at link-time. This refactoring is necessary for adding
bytecode serialization functionality, as explained by the revised
comments in this commit.
-
a67db612
by Cheng Shao at 2025-05-20T17:22:19-04:00
compiler: make bc_strs serializable
This commit makes the bc_strs field in CompiledByteCode serializable;
similar to previous commit, we preserve the ByteString directly and
defer the actual allocation to link-time, as mentioned in updated
comment.
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5faf34ef
by Cheng Shao at 2025-05-20T17:22:19-04:00
compiler: make bc_itbls serializable
This commit makes bc_itbls in CompiledByteCode serializable. A
dedicated ConInfoTable datatype has been added in ghci which is the
recipe for dynamically making a datacon's info table, containing the
payload of the MkConInfoTable iserv message.
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2abaf8c1
by Cheng Shao at 2025-05-20T17:22:19-04:00
compiler: remove FFIInfo bookkeeping in BCO
This commit removes the bc_ffis field from CompiledByteCode
completely, as well as all the related bookkeeping logic in
GHC.StgToByteCode. bc_ffis is actually *unused* in the rest of GHC
codebase! It is merely a list of FFIInfo, which is just a remote
pointer of the libffi ffi_cif struct; once we allocate the ffi_cif
struct and put its pointer in a CCALL instruction, we'll never free it
anyway. So there is no point of bookkeeping.
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adb9e4d2
by Cheng Shao at 2025-05-20T17:22:19-04:00
compiler: make FFIInfo serializable in BCO
This commit makes all the FFIInfo needed in CCALL instructions
serializable. Previously, when doing STG to BCO lowering, we would
allocate a libffi ffi_cif struct and keep its remote pointer as
FFIInfo; but actually we can just keep the type signature as FFIInfo
and defer the actual allocation to link-time.
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200f401b
by Cheng Shao at 2025-05-20T17:22:19-04:00
ghci: remove redundant NewBreakModule message
This commit removes the redundant NewBreakModule message from ghci: it
just allocates two strings! This functionality can be implemented with
existing MallocStrings in one iserv call.
-
ddaadca6
by Cheng Shao at 2025-05-20T17:22:19-04:00
compiler: make breakpoint module name and unit id serializable
This commit makes breakpoint module name and unit id serializable, in
BRK_FUN instructions as well as ModBreaks. We can simply keep the
module name and unit ids, and defer the buffer allocation to link
time.
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a0fde202
by Cheng Shao at 2025-05-20T17:22:19-04:00
compiler: remove unused newModule
This commit removes the now unused newModule function from GHC.
-
68c8f140
by Cheng Shao at 2025-05-20T17:22:19-04:00
compiler: add BCONPtrFS for interned top level string literals in BCO
This commit adds BCONPtrFS as a BCO non-pointer literal kind, which
has the same semantics of BCONPtrStr, except it contains a FastString
instead of a ByteString. By using BCONPtrFS to represent top level
string literals that are already FastString in the compilation
pipeline, we enjoy the FastString interning logic and avoid allocating
a bunch of redundant ByteStrings for the same FastStrings, especially
when we lower the BRK_FUN instruction.
-
f2b532bc
by Peng Fan at 2025-05-20T17:23:15-04:00
hadrian: enable GHCi for loongarch64
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8ded2330
by kwxm at 2025-05-20T17:24:07-04:00
Fix bugs in `integerRecipMod` and `integerPowMod`
This fixes #26017.
* `integerRecipMod x 1` now returns `(# 1 | #)` for all x; previously it
incorrectly returned `(# | () #)`, indicating failure.
* `integerPowMod 0 e m` now returns `(# | () #)` for e<0 and m>1, indicating
failure; previously it incorrectly returned `(# 0 | #)`.
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c9abb87c
by Andreas Klebinger at 2025-05-20T17:24:50-04:00
Specialise: Don't float out constraint components.
It was fairly complex to do so and it doesn't seem to improve anything.
Nofib allocations were unaffected as well.
See also Historical Note [Floating dictionaries out of cases]
-
202b201c
by Andreas Klebinger at 2025-05-21T10:16:14-04:00
Interpreter: Add limited support for direct primop evaluation.
This commit adds support for a number of primops directly
to the interpreter. This avoids the indirection of going
through the primop wrapper for those primops speeding interpretation
of optimized code up massively.
Code involving IntSet runs about 25% faster with optimized core and these
changes. For core without breakpoints it's even more pronouced and I
saw reductions in runtime by up to 50%.
Running GHC itself in the interpreter was sped up by ~15% through this
change.
Additionally this comment does a few other related changes:
testsuite:
* Run foundation test in ghci and ghci-opt ways to test these
primops.
* Vastly expand the foundation test to cover all basic primops
by comparing result with the result of calling the wrapper.
Interpreter:
* When pushing arguments for interpreted primops extend each argument to
at least word with when pushing. This avoids some issues with big
endian. We can revisit this if it causes performance issues.
* Restructure the stack chunk check logic. There are now macros for
read accesses which might cross stack chunk boundries and macros which
omit the checks which are used when we statically know we access an
address in the current stack chunk.
-
67a177b4
by sheaf at 2025-05-21T10:17:04-04:00
QuickLook: do a shape test before unifying
This commit ensures we do a shape test before unifying. This ensures
we don't try to unify a TyVarTv with a non-tyvar, e.g.
alpha[tyv] := Int
On the way, we refactor simpleUnifyCheck:
1. Move the checkTopShape check into simpleUnifyCheck
2. Refactors simpleUnifyCheck to return a value of the new type
SimpleUnifyResult type. Now, simpleUnifyCheck returns "can unify",
"cannot unify" or "dunno" (with "cannot unify" being the new result
it can return). Now:
- touchabilityTest is included; it it fails we return "cannot unify"
- checkTopShape now returns "cannot unify" instead of "dunno" upon failure
3. Move the call to simpleUnifyCheck out of checkTouchableTyVarEq.
After that, checkTouchableTyVarEq becames a simple call to
checkTyEqRhs, so we inline it.
This allows the logic in canEqCanLHSFinish_try_unification to be simplified.
In particular, we now avoid calling 'checkTopShape' twice.
Two further changes suggested by Simon were also implemented:
- In canEqCanLHSFinish, if checkTyEqRhs returns PuFail with
'do_not_prevent_rewriting', we now **continue with this constraint**.
This allows us to use the constraint for rewriting.
- checkTyEqRhs now has a top-level check to avoid flattening a tyfam app
in a top-level equality of the form alpha ~ F tys, as this is
going around in circles. This simplifies the implementation without
any change in behaviour.
Fixes #25950
Fixes #26030
-
4020972c
by sheaf at 2025-05-21T10:17:04-04:00
FixedRuntimeRepError: omit unhelpful explanation
This commit tweaks the FixedRuntimeRepError case of pprTcSolverReportMsg,
to avoid including an explanation which refers to a type variable that
appears nowhere else.
For example, the old error message could look like the following:
The pattern binding does not have a fixed runtime representation.
Its type is:
T :: TYPE R
Cannot unify ‘R’ with the type variable ‘c0’
because the former is not a concrete ‘RuntimeRep’.
With this commit, we now omit the last two lines, because the concrete
type variable (here 'c0') does not appear in the type displayed to the
user (here 'T :: TYPE R').
-
8b289b41
by Andreas Klebinger at 2025-05-21T17:32:13+02:00
Specialise: Improve specialisation by refactoring interestingDict
This MR addresses #26051, which concerns missed type-class specialisation.
The main payload of the MR is to completely refactor the key function
`interestingDict` in GHC.Core.Opt.Specialise
The main change is that we now also look at the structure of the
dictionary we consider specializing on, rather than only the type.
See the big `Note [Interesting dictionary arguments]`