- 06 Nov, 2020 5 commits
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Krzysztof Gogolewski authored
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See Note [Racing weak pointer evacuation] for all of the gory details.
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1) Don't modify DynFlags (too much) for -dynamic-too: now when we generate dynamic outputs for "-dynamic-too", we only set "dynamicNow" boolean field in DynFlags instead of modifying several other fields. These fields now have accessors that take dynamicNow into account. 2) Use DynamicTooState ADT to represent -dynamic-too state. It's much clearer than the undocumented "DynamicTooConditional" that was used before. As a result, we can finally remove the hscs_iface_dflags field in HscRecomp. There was a comment on this field saying: "FIXME (osa): I don't understand why this is necessary, but I spent almost two days trying to figure this out and I couldn't .. perhaps someone who understands this code better will remove this later." I don't fully understand the details, but it was needed because of the changes made to the DynFlags for -dynamic-too. There is still something very dubious in GHC.Iface.Recomp: we have to disable the "dynamicNow" flag at some point for some Backpack's "heinous hack" to continue to work. It may be because interfaces for indefinite units are always non-dynamic, or because we mix and match dynamic and non-dynamic interfaces (#9176), or something else, who knows?
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This refactors the GHC AST to remove `HsImplicitBndrs` and replace it with `HsOuterTyVarBndrs`, a type which records whether the outermost quantification in a type is explicit (i.e., with an outermost, invisible `forall`) or implicit. As a result of this refactoring, it is now evident in the AST where the `forall`-or-nothing rule applies: it's all the places that use `HsOuterTyVarBndrs`. See the revamped `Note [forall-or-nothing rule]` in `GHC.Hs.Type` (previously in `GHC.Rename.HsType`). Moreover, the places where `ScopedTypeVariables` brings lexically scoped type variables into scope are a subset of the places that adhere to the `forall`-or-nothing rule, so this also makes places that interact with `ScopedTypeVariables` easier to find. See the revamped `Note [Lexically scoped type variables]` in `GHC.Hs.Type` (previously in `GHC.Tc.Gen.Sig`). `HsOuterTyVarBndrs` are used in type signatures (see `HsOuterSigTyVarBndrs`) and type family equations (see `HsOuterFamEqnTyVarBndrs`). The main difference between the former and the latter is that the former cares about specificity but the latter does not. There are a number of knock-on consequences: * There is now a dedicated `HsSigType` type, which is the combination of `HsOuterSigTyVarBndrs` and `HsType`. `LHsSigType` is now an alias for an `XRec` of `HsSigType`. * Working out the details led us to a substantial refactoring of the handling of explicit (user-written) and implicit type-variable bindings in `GHC.Tc.Gen.HsType`. Instead of a confusing family of higher order functions, we now have a local data type, `SkolemInfo`, that controls how these binders are kind-checked. It remains very fiddly, not fully satisfying. But it's better than it was. Fixes #16762. Bumps the Haddock submodule. Co-authored-by:
Simon Peyton Jones <simonpj@microsoft.com> Co-authored-by:
Richard Eisenberg <rae@richarde.dev> Co-authored-by:
Zubin Duggal <zubin@cmi.ac.in>
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- 05 Nov, 2020 2 commits
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Commit f594a68a (`Use level numbers for generalisation`) ended up fixing #18920. Let's add a regression test to ensure that it stays fixed. Fixes #18920.
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The atomic Exchange and CAS operations on integral types are updated to take and return more natural `Word#` rather than `Int#` values. These are bit-block not arithmetic operations, and the sign bit plays no special role. Standardises the names to `atomic<OpType><ValType>Addr#`, where `OpType` is one of `Cas` or `Exchange` and `ValType` is presently either `Word` or `Addr`. Eventually, variants for `Word32` and `Word64` can and should be added, once #11953 and related issues (e.g. #13825) are resolved. Adds tests for `Addr#` CAS that mirror existing tests for `MutableByteArray#`.
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- 04 Nov, 2020 3 commits
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We can now supply additional package dbs to the testsuite. For make the package db can be supplied by passing PACKAGE_DB=/path/to/db. In the testsuite driver it's passed via the --test-package-db argument.
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We no compare these by doing 64bit subtraction and checking the resulting flags. We used to do this differently but the old approach was broken when the high bits compared equal and the comparison was one of >= or <=. The new approach should be both correct and faster.
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- 03 Nov, 2020 12 commits
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bignat_add was a loopbreaker with an INLINE pragma (spotted by @mpickering). This patch makes it non recursive to avoid the issue.
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Constant-folding rules for integerToWord/integerToInt were performing the following coercions at compilation time: integerToWord: target's Integer -> ghc's Word -> target's Word integerToInt : target's Integer -> ghc's Int -> target's Int 1) It was wrong for cross-compilers when GHC's word size is smaller than the target one. This patch avoids passing through GHC's word-sized types: integerToWord: target's Integer -> ghc's Integer -> target's Word integerToInt : target's Integer -> ghc's Integer -> target's Int 2) Additionally we didn't wrap the target word/int literal to make it fit into the target's range! This broke the invariant of literals only containing values in range. The existing code is wrong only with a 64-bit cross-compiling GHC, targeting a 32-bit platform, and performing constant folding on a literal that doesn't fit in a 32-bit word. If GHC was built with DEBUG, the assertion in GHC.Types.Literal.mkLitWord would fail. Otherwise the bad transformation would go unnoticed. -
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This disallows `a %001 -> b`, and makes sure the type literal is printed from its SourceText so it is clear why. Closes #18888
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Move linker related code into GHC.Linker. Previously it was scattered into GHC.Unit.State, GHC.Driver.Pipeline, GHC.Runtime.Linker, etc. Add documentation in GHC.Linker
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There are a few reasons why capturing the output of the RunTest builder is undesirable: * there is a large amount of output which then gets unnecessarily duplicated by Hadrian if the builder fails * the output may contain codepoints which are unrepresentable in the current codepage on Windows, causing Hadrian to crash * capturing the output causes the testsuite driver to disable its colorisation logic, making the output less legible.
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The User's Guide claims that `:kind!` should expand type synonyms, but GHCi wasn't doing this in practice. Let's just update the implementation to match the specification in the User's Guide. Fixes #13795. Fixes #18828. Co-authored-by:Ryan Scott <ryan.gl.scott@gmail.com>
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Previously, the functions in `GHC.Core.Lint` used a patchwork of different ways to display Core Lint errors: * `lintPassResult` (which is the source of most Core Lint errors) renders Core Lint errors with a distinctive banner (e.g., `*** Core Lint errors : in result of ... ***`) that sets them apart from ordinary GHC error messages. * `lintAxioms`, in contrast, uses a completely different code path that displays Core Lint errors in a rather confusing manner. For example, the program in #18770 would give these results: ``` Bug.hs:1:1: error: Bug.hs:12:1: warning: Non-*-like kind when *-like expected: RuntimeRep when checking the body of forall: 'TupleRep '[r] In the coercion axiom Bug.N:T :: []. Bug.T ~_R Any Substitution: [TCvSubst In scope: InScope {r} Type env: [axl :-> r] Co env: []] | 1 | {-# LANGUAGE DataKinds #-} | ^ ``` * Further digging reveals that `GHC.IfaceToCore` displays Core Lint errors for iface unfoldings as though they were a GHC panic. See, for example, this excerpt from #17723: ``` ghc: panic! (the 'impossible' happened) (GHC version 8.8.2 for x86_64-unknown-linux): Iface Lint failure In interface for Lib ... ``` This patch makes all of these code paths display Core Lint errors and warnings consistently. I decided to adopt the conventions that `lintPassResult` currently uses, as they appear to have been around the longest (and look the best, in my subjective opinion). We now use the `displayLintResult` function for all three scenarios mentioned above. For example, here is what the Core Lint error for the program in #18770 looks like after this patch: ``` [1 of 1] Compiling Bug ( Bug.hs, Bug.o ) *** Core Lint errors : in result of TcGblEnv axioms *** Bug.hs:12:1: warning: Non-*-like kind when *-like expected: RuntimeRep when checking the body of forall: 'TupleRep '[r_axn] In the coercion axiom N:T :: []. T ~_R Any Substitution: [TCvSubst In scope: InScope {r_axn} Type env: [axn :-> r_axn] Co env: []] *** Offending Program *** axiom N:T :: T = Any -- Defined at Bug.hs:12:1 *** End of Offense *** <no location info>: error: Compilation had errors ``` Fixes #18770.
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The `rts_pause` and `rts_resume` functions have been added to `RtsAPI.h` and allow an external process to completely pause and resume the RTS. Co-authored-by:
Sven Tennie <sven.tennie@gmail.com>
Co-authored-by: 
Matthew Pickering <matthewtpickering@gmail.com>
Co-authored-by: Ben Gamari <bgamari.foss@gmail.com>
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We do not support foreign "C" imports of varargs functions. While this works on amd64, in general the platform's calling convention may need more type information that our Cmm representation can currently provide. For instance, this is the case with Darwin's AArch64 calling convention. Document this fact in the users guide and fix T5423 which makes use of a disallowed foreign import. Closes #18854.
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This allows us to make `config.top` a proper Path. Previously it was a str, which caused the Ghostscript detection logic to break.
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- 01 Nov, 2020 4 commits
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This potentially saves a cache miss per scavenge.
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This patch was authored by David Feuer <david.feuer@gmail.com>
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- 31 Oct, 2020 8 commits
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Previously these were mostly undocumented and was ripe for potential inconsistencies.
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This file will be generated.
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See #18032 for the details. * Use `Lit (LitNumber _ i)` instead of `isLitValue_maybe` which does more work but that is not needed for constant-folding * Don't export `GHC.Types.Literal.isLitValue_maybe` * Kill `GHC.Types.Literal.isLitValue` which isn't used
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Avoid the use of global pattern synonyms. 1) I think it's going to be helpful to implement constant folding for other numeric types, especially Natural which doesn't have a wrapping behavior. We'll have to refactor these rules even more so we'd better make them less cryptic. 2) It should also be slightly faster because global pattern synonyms matched operations for every numeric types instead of the current one: e.g., ":**:" pattern was matching multiplication for both Int# and Word# types. As we will probably want to implement constant folding for other numeric types (Int8#, Int16#, etc.), it is more efficient to only match primops for a given type as we do now.
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Previously, `can_eq_nc'` would equate `ForAllTy`s regardless of their `ArgFlag`, including `forall i -> i -> Type` and `forall i. i -> Type`! To fix this, `can_eq_nc'` now uses the `sameVis` function to first check if the `ArgFlag`s are equal modulo specificity. I have also updated `tcEqType`'s implementation to match this behavior. For more explanation on the "modulo specificity" part, see the new `Note [ForAllTy and typechecker equality]` in `GHC.Tc.Solver.Canonical`. While I was in town, I fixed some related documentation issues: * I added `Note [Typechecker equality]` to `GHC.Tc.Utils.TcType` to describe what exactly distinguishes `can_eq_nc'` and `tcEqType` (which implement typechecker equality) from `eqType` (which implements definitional equality, which does not care about the `ArgFlags` of `ForAllTy`s at all). * The User's Guide had some outdated prose on the specified/inferred distinction being different for types and kinds, a holdover from #15079. This is no longer the case on today's GHC, so I removed this prose, added some new prose to take its place, and added a regression test for the programs in #15079. * The User's Guide had some _more_ outdated prose on inferred type variables not being allowed in `default` type signatures for class methods, which is no longer true as of the resolution of #18432. * The related `Note [Deferred Unification]` was being referenced as `Note [Deferred unification]` elsewhere, which made it harder to `grep` for. I decided to change the name of the Note to `Deferred unification` for consistency with the capitalization style used for most other Notes. Fixes #18863.
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- 30 Oct, 2020 3 commits
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Haskell98 and GADT constructors both use `HsConDeclDetails`, which includes `InfixCon`. But `InfixCon` is never used for GADT constructors, which results in an awkward unrepresentable state. This removes the unrepresentable state by: * Renaming the existing `HsConDeclDetails` synonym to `HsConDeclH98Details`, which emphasizes the fact that it is now only used for Haskell98-style data constructors, and * Creating a new `HsConDeclGADTDetails` data type with `PrefixConGADT` and `RecConGADT` constructors that closely resemble `PrefixCon` and `InfixCon` in `HsConDeclH98Details`. The key difference is that `HsConDeclGADTDetails` lacks any way to represent infix constructors. The rest of the patch is refactoring to accommodate the new structure of `HsConDecl{H98,GADT}Details`. Some highlights: * The `getConArgs` and `hsConDeclArgTys` functions have been removed, as there is no way to implement these functions uniformly for all `ConDecl`s. For the most part, their previous call sites now pattern match on the `ConDecl`s directly and do different things for `ConDeclH98`s and `ConDeclGADT`s. I did introduce one new function to make the transition easier: `getRecConArgs_maybe`, which extracts the arguments from a `RecCon(GADT)`. This is still possible since `RecCon(GADT)`s still use the same representation in both `HsConDeclH98Details` and `HsConDeclGADTDetails`, and since the pattern that `getRecConArgs_maybe` implements is used in several places, I thought it worthwhile to factor it out into its own function. * Previously, the `con_args` fields in `ConDeclH98` and `ConDeclGADT` were both of type `HsConDeclDetails`. Now, the former is of type `HsConDeclH98Details`, and the latter is of type `HsConDeclGADTDetails`, which are distinct types. As a result, I had to rename the `con_args` field in `ConDeclGADT` to `con_g_args` to make it typecheck. A consequence of all this is that the `con_args` field is now partial, so using `con_args` as a top-level field selector is dangerous. (Indeed, Haddock was using `con_args` at the top-level, which caused it to crash at runtime before I noticed what was wrong!) I decided to add a disclaimer in the 9.2.1 release notes to advertise this pitfall. Fixes #18844. Bumps the `haddock` submodule. -
vdukhovni authored
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While, say, alternating "he" and "she" in sequential writing may be nicer than always using "they", reading code/documentation is almost never sequential. If this small change makes individuals feel more welcome in GHC's codebase, that's a good thing.
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- 29 Oct, 2020 3 commits
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Ryan Scott authored
This fixes #18723 by: * Moving the existing `GHC.Tc.Gen.HsType.bigConstraintTuple` validity check to `GHC.Rename.Utils.checkCTupSize` for consistency with `GHC.Rename.Utils.checkTupSize`, and * Using `check(C)TupSize` when checking tuple _types_, in addition to checking names, expressions, and patterns. Note that I put as many of these checks as possible in the typechecker so that GHC can properly distinguish between boxed and constraint tuples. The exception to this rule is checking names, which I perform in the renamer (in `GHC.Rename.Env`) so that we can rule out `(,, ... ,,)` and `''(,, ... ,,)` alike in one fell swoop. While I was in town, I also removed the `HsConstraintTuple` and `HsBoxedTuple` constructors of `HsTupleSort`, which are functionally unused. This requires a `haddock` submodule bump.
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I was working on making DynFlags stateless (#17957), especially by storing loaded plugins into HscEnv instead of DynFlags. It turned out to be complicated because HscEnv is in GHC.Driver.Types but LoadedPlugin isn't: it is in GHC.Driver.Plugins which depends on GHC.Driver.Types. I didn't feel like introducing yet another hs-boot file to break the loop. Additionally I remember that while we introduced the module hierarchy (#13009) we talked about splitting GHC.Driver.Types because it contained various unrelated types and functions, but we never executed. I didn't feel like making GHC.Driver.Types bigger with more unrelated Plugins related types, so finally I bit the bullet and split GHC.Driver.Types. As a consequence this patch moves a lot of things. I've tried to put them into appropriate modules but nothing is set in stone. Several other things moved to avoid loops. * Removed Binary instances from GHC.Utils.Binary for random compiler things * Moved Typeable Binary instances into GHC.Utils.Binary.Typeable: they import a lot of things that users of GHC.Utils.Binary don't want to depend on. * put everything related to Units/Modules under GHC.Unit: GHC.Unit.Finder, GHC.Unit.Module.{ModGuts,ModIface,Deps,etc.} * Created several modules under GHC.Types: GHC.Types.Fixity, SourceText, etc. * Split GHC.Utils.Error (into GHC.Types.Error) * Finally removed GHC.Driver.Types Note that this patch doesn't put loaded plugins into HscEnv. It's left for another patch. Bump haddock submodule
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