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* Force the Docs structure to prevent leaks in GHCi with -haddock without ↵wip/force-docsZubin Duggal2023-01-031-2/+2
| | | | | | | | | | -fwrite-interface Involves adding many new NFData instances. Without forcing Docs, references to the TcGblEnv for each module are retained by the Docs structure. Usually these are forced when the ModIface is serialised but not when we aren't writing the interface.
* Package Imports: Get candidate packages also from re-exported modulesMatthew Pickering2022-12-152-3/+15
| | | | | | | | Previously we were just looking at the direct imports to try and work out what a package qualifier could apply to but #22333 pointed out we also needed to look for reexported modules. Fixes #22333
* Add Javascript backendSylvain Henry2022-11-291-1/+3
| | | | | | | | | | | | | | | Add JS backend adapted from the GHCJS project by Luite Stegeman. Some features haven't been ported or implemented yet. Tests for these features have been disabled with an associated gitlab ticket. Bump array submodule Work funded by IOG. Co-authored-by: Jeffrey Young <jeffrey.young@iohk.io> Co-authored-by: Luite Stegeman <stegeman@gmail.com> Co-authored-by: Josh Meredith <joshmeredith2008@gmail.com>
* Use a more efficient printer for code generation (#21853)Krzysztof Gogolewski2022-11-111-12/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The changes in `GHC.Utils.Outputable` are the bulk of the patch and drive the rest. The types `HLine` and `HDoc` in Outputable can be used instead of `SDoc` and support printing directly to a handle with `bPutHDoc`. See Note [SDoc versus HDoc] and Note [HLine versus HDoc]. The classes `IsLine` and `IsDoc` are used to make the existing code polymorphic over `HLine`/`HDoc` and `SDoc`. This is done for X86, PPC, AArch64, DWARF and dependencies (printing module names, labels etc.). Co-authored-by: Alexis King <lexi.lambda@gmail.com> Metric Decrease: CoOpt_Read ManyAlternatives ManyConstructors T10421 T12425 T12707 T13035 T13056 T13253 T13379 T18140 T18282 T18698a T18698b T1969 T20049 T21839c T21839r T3064 T3294 T4801 T5321FD T5321Fun T5631 T6048 T783 T9198 T9233
* Fire RULES in the SpecialiserSimon Peyton Jones2022-11-101-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Specialiser has, for some time, fires class-op RULES in the specialiser itself: see Note [Specialisation modulo dictionary selectors] This MR beefs it up a bit, so that it fires /all/ RULES in the specialiser, not just class-op rules. See Note [Fire rules in the specialiser] The result is a bit more specialisation; see test simplCore/should_compile/T21851_2 This pushed me into a bit of refactoring. I made a new data types GHC.Core.Rules.RuleEnv, which combines - the several source of rules (local, home-package, external) - the orphan-module dependencies in a single record for `getRules` to consult. That drove a bunch of follow-on refactoring, including allowing me to remove cr_visible_orphan_mods from the CoreReader data type. I moved some of the RuleBase/RuleEnv stuff into GHC.Core.Rule. The reorganisation in the Simplifier improve compile times a bit (geom mean -0.1%), but T9961 is an outlier Metric Decrease: T9961
* Minor refactor around FastStringsKrzysztof Gogolewski2022-11-051-3/+2
| | | | | | | Pass FastStrings to functions directly, to make sure the rule for fsLit "literal" fires. Remove SDoc indirection in GHCi.UI.Tags and GHC.Unit.Module.Graph.
* Export pprTrace and friends from GHC.Prelude.Andreas Klebinger2022-11-032-1/+2
| | | | | Introduces GHC.Prelude.Basic which can be used in modules which are a dependency of the ppr code.
* Clarify status of bindings in WholeCoreBindingsMatthew Pickering2022-11-031-3/+3
| | | | | | | | | Gergo points out that these bindings are tidied, rather than prepd as the variable claims. Therefore we update the name of the variable to reflect reality and add a comment to the data type to try to erase any future confusion. Fixes #22307
* Expose UnitEnvGraphKey for user-codeFendor2022-11-011-0/+1
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* Typo: rename -fwrite-if-simplfied-core to -fwrite-if-simplified-coreKrzysztof Gogolewski2022-11-011-2/+2
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* Remove source location information from interface filesOwen Shepherd2022-10-271-8/+8
| | | | | | | | | | | | | This change aims to minimize source location information leaking into interface files, which makes ABI hashes dependent on the build location. The `Binary (Located a)` instance has been removed completely. It seems that the HIE interface still needs the ability to serialize SrcSpans, but by wrapping the instances, it should be a lot more difficult to inadvertently add source location information.
* Cleanup String/FastString conversionsKrzysztof Gogolewski2022-10-251-1/+1
| | | | | | | Remove unused mkPtrString and isUnderscoreFS. We no longer use mkPtrString since 1d03d8bef96. Remove unnecessary conversions between FastString and String and back.
* Scrub various partiality involving lists (again).M Farkas-Dyck2022-10-191-1/+5
| | | | Lets us avoid some use of `head` and `tail`, and some panics.
* Interface Files with Core DefinitionsMatthew Pickering2022-10-115-16/+151
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit adds three new flags * -fwrite-if-simplified-core: Writes the whole core program into an interface file * -fbyte-code-and-object-code: Generate both byte code and object code when compiling a file * -fprefer-byte-code: Prefer to use byte-code if it's available when running TH splices. The goal for including the core bindings in an interface file is to be able to restart the compiler pipeline at the point just after simplification and before code generation. Once compilation is restarted then code can be created for the byte code backend. This can significantly speed up start-times for projects in GHCi. HLS already implements its own version of these extended interface files for this reason. Preferring to use byte-code means that we can avoid some potentially expensive code generation steps (see #21700) * Producing object code is much slower than producing bytecode, and normally you need to compile with `-dynamic-too` to produce code in the static and dynamic way, the dynamic way just for Template Haskell execution when using a dynamically linked compiler. * Linking many large object files, which happens once per splice, can be quite expensive compared to linking bytecode. And you can get GHC to compile the necessary byte code so `-fprefer-byte-code` has access to it by using `-fbyte-code-and-object-code`. Fixes #21067
* Scrub various partiality involving empty lists.M Farkas-Dyck2022-09-301-2/+2
| | | | Avoids some uses of `head` and `tail`, and some panics when an argument is null.
* Clean up `findWiredInUnit`. In particular, avoid `head`.M Farkas-Dyck2022-09-281-12/+10
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* Minor refactor around OutputableKrzysztof Gogolewski2022-09-221-2/+0
| | | | | | | * Replace 'text . show' and 'ppr' with 'int'. * Remove Outputable.hs-boot, no longer needed * Use pprWithCommas * Factor out instructions in AArch64 codegen
* Clean up some. In particular:M Farkas-Dyck2022-09-172-6/+5
| | | | | | | | | | • Delete some dead code, largely under `GHC.Utils`. • Clean up a few definitions in `GHC.Utils.(Misc, Monad)`. • Clean up `GHC.Types.SrcLoc`. • Derive stock `Functor, Foldable, Traversable` for more types. • Derive more instances for newtypes. Bump haddock submodule.
* Fix typosEric Lindblad2022-09-145-8/+8
| | | | | | | This fixes various typos and spelling mistakes in the compiler. Fixes #21891
* Add diagnostic codessheaf2022-09-131-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This MR adds diagnostic codes, assigning unique numeric codes to error and warnings, e.g. error: [GHC-53633] Pattern match is redundant This is achieved as follows: - a type family GhcDiagnosticCode that gives the diagnostic code for each diagnostic constructor, - a type family ConRecursInto that specifies whether to recur into an argument of the constructor to obtain a more fine-grained code (e.g. different error codes for different 'deriving' errors), - generics machinery to generate the value-level function assigning each diagnostic its error code; see Note [Diagnostic codes using generics] in GHC.Types.Error.Codes. The upshot is that, to add a new diagnostic code, contributors only need to modify the two type families mentioned above. All logic relating to diagnostic codes is thus contained to the GHC.Types.Error.Codes module, with no code duplication. This MR also refactors error message datatypes a bit, ensuring we can derive Generic for them, and cleans up the logic around constraint solver reports by splitting up 'TcSolverReportInfo' into separate datatypes (see #20772). Fixes #21684
* Cleanups around pretty-printingKrzysztof Gogolewski2022-08-091-1/+1
| | | | | | | | | | * Remove hack when printing OccNames. No longer needed since e3dcc0d5 * Remove unused `pprCmms` and `instance Outputable Instr` * Simplify `pprCLabel` (no need to pass platform) * Remove evil `Show`/`Eq` instances for `SDoc`. They were needed by ImmLit, but that can take just a String instead. * Remove instance `Outputable CLabel` - proper output of labels needs a platform, and is done by the `OutputableP` instance
* Fix leaks in --make mode when there are module loopsMatthew Pickering2022-08-042-2/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes quite a tricky leak where we would end up retaining stale ModDetails due to rehydrating modules against non-finalised interfaces. == Loops with multiple boot files It is possible for a module graph to have a loop (SCC, when ignoring boot files) which requires multiple boot files to break. In this case we must perform the necessary hydration steps before and after compiling modules which have boot files which are described above for corectness but also perform an additional hydration step at the end of the SCC to remove space leaks. Consider the following example: ┌───────┐ ┌───────┐ │ │ │ │ │ A │ │ B │ │ │ │ │ └─────┬─┘ └───┬───┘ │ │ ┌────▼─────────▼──┐ │ │ │ C │ └────┬─────────┬──┘ │ │ ┌────▼──┐ ┌───▼───┐ │ │ │ │ │ A-boot│ │ B-boot│ │ │ │ │ └───────┘ └───────┘ A, B and C live together in a SCC. Say we compile the modules in order A-boot, B-boot, C, A, B then when we compile A we will perform the hydration steps (because A has a boot file). Therefore C will be hydrated relative to A, and the ModDetails for A will reference C/A. Then when B is compiled C will be rehydrated again, and so B will reference C/A,B, its interface will be hydrated relative to both A and B. Now there is a space leak because say C is a very big module, there are now two different copies of ModDetails kept alive by modules A and B. The way to avoid this space leak is to rehydrate an entire SCC together at the end of compilation so that all the ModDetails point to interfaces for .hs files. In this example, when we hydrate A, B and C together then both A and B will refer to C/A,B. See #21900 for some more discussion. ------------------------------------------------------- In addition to this simple case, there is also the potential for a leak during parallel upsweep which is also fixed by this patch. Transcibed is Note [ModuleNameSet, efficiency and space leaks] Note [ModuleNameSet, efficiency and space leaks] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ During unsweep the results of compiling modules are placed into a MVar, to find the environment the module needs to compile itself in the MVar is consulted and the HomeUnitGraph is set accordingly. The reason we do this is that precisely tracking module dependencies and recreating the HUG from scratch each time is very expensive. In serial mode (-j1), this all works out fine because a module can only be compiled after its dependencies have finished compiling and not interleaved with compiling module loops. Therefore when we create the finalised or no loop interfaces, the HUG only contains finalised interfaces. In parallel mode, we have to be more careful because the HUG variable can contain non-finalised interfaces which have been started by another thread. In order to avoid a space leak where a finalised interface is compiled against a HPT which contains a non-finalised interface we have to restrict the HUG to only the visible modules. The visible modules is recording in the ModuleNameSet, this is propagated upwards whilst compiling and explains which transitive modules are visible from a certain point. This set is then used to restrict the HUG before the module is compiled to only the visible modules and thus avoiding this tricky space leak. Efficiency of the ModuleNameSet is of utmost importance because a union occurs for each edge in the module graph. Therefore the set is represented directly as an IntSet which provides suitable performance, even using a UniqSet (which is backed by an IntMap) is too slow. The crucial test of performance here is the time taken to a do a no-op build in --make mode. See test "jspace" for an example which used to trigger this problem. Fixes #21900
* Refactored Simplify passDominik Peteler2022-07-222-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * Removed references to driver from GHC.Core.LateCC, GHC.Core.Simplify namespace and GHC.Core.Opt.Stats. Also removed services from configuration records. * Renamed GHC.Core.Opt.Simplify to GHC.Core.Opt.Simplify.Iteration. * Inlined `simplifyPgm` and renamed `simplifyPgmIO` to `simplifyPgm` and moved the Simplify driver to GHC.Core.Opt.Simplify. * Moved `SimplMode` and `FloatEnable` to GHC.Core.Opt.Simplify.Env. * Added a configuration record `TopEnvConfig` for the `SimplTopEnv` environment in GHC.Core.Opt.Simplify.Monad. * Added `SimplifyOpts` and `SimplifyExprOpts`. Provide initialization functions for those in a new module GHC.Driver.Config.Core.Opt.Simplify. Also added initialization functions for `SimplMode` to that module. * Moved `CoreToDo` and friends to a new module GHC.Core.Pipeline.Types and the counting types and functions (`SimplCount` and `Tick`) to new module GHC.Core.Opt.Stats. * Added getter functions for the fields of `SimplMode`. The pedantic bottoms option and the platform are retrieved from the ArityOpts and RuleOpts and the getter functions allow us to retrieve values from `SpecEnv` without the knowledge where the data is stored exactly. * Moved the coercion optimization options from the top environment to `SimplMode`. This way the values left in the top environment are those dealing with monadic functionality, namely logging, IO related stuff and counting. Added a note "The environments of the Simplify pass". * Removed `CoreToDo` from GHC.Core.Lint and GHC.CoreToStg.Prep and got rid of `CoreDoSimplify`. Pass `SimplifyOpts` in the `CoreToDo` type instead. * Prep work before removing `InteractiveContext` from `HscEnv`.
* Fix potential space leak that arise from ModuleGraphs retaining referencesZubin Duggal2022-07-131-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | to previous ModuleGraphs, in particular the lazy `mg_non_boot` field. This manifests in `extendMG`. Solution: Delete `mg_non_boot` as it is only used for `mgLookupModule`, which is only called in two places in the compiler, and should only be called at most once for every home unit: GHC.Driver.Make: mainModuleSrcPath :: Maybe String mainModuleSrcPath = do ms <- mgLookupModule mod_graph (mainModIs hue) ml_hs_file (ms_location ms) GHCI.UI: listModuleLine modl line = do graph <- GHC.getModuleGraph let this = GHC.mgLookupModule graph modl Instead `mgLookupModule` can be a linear function that looks through the entire list of `ModuleGraphNodes` Fixes #21816
* driver: Fix issue with module loops and multiple home unitsMatthew Pickering2022-07-061-0/+6
| | | | | | | | | | We were attempting to rehydrate all dependencies of a particular module, but we actually only needed to rehydrate those of the current package (as those are the ones participating in the loop). This fixes loading GHC into a multi-unit session. Fixes #21814
* Refactor ModuleName to L.H.S.Module.Nameromes2022-07-038-107/+11
| | | | | | | | | | | | | | | ModuleName used to live in GHC.Unit.Module.Name. In this commit, the definition of ModuleName and its associated functions are moved to Language.Haskell.Syntax.Module.Name according to the current plan towards making the AST GHC-independent. The instances for ModuleName for Outputable, Uniquable and Binary were moved to the module in which the class is defined because these instances depend on GHC. The instance of Eq for ModuleName is slightly changed to no longer depend on unique explicitly and instead uses FastString's instance of Eq.
* TTG: Move ImpExp client-independent bits to L.H.S.ImpExpromes2022-07-034-15/+8
| | | | | | | | | | | Move the GHC-independent definitions from GHC.Hs.ImpExp to Language.Haskell.Syntax.ImpExp with the required TTG extension fields such as to keep the AST independent from GHC. This is progress towards having the haskell-syntax package, as described in #21592 Bumps haddock submodule
* TTG: Move HsModule to L.H.Sromes2022-07-033-10/+8
| | | | | | | | | Move the definition of HsModule defined in GHC.Hs to Language.Haskell.Syntax with an added TTG parameter and corresponding extension fields. This is progress towards having the haskell-syntax package, as described in #21592
* Desugar RecordUpd in `tcExpr`wip/T18802CarrieMY2022-05-251-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch typechecks record updates by desugaring them inside the typechecker using the HsExpansion mechanism, and then typechecking this desugared result. Example: data T p q = T1 { x :: Int, y :: Bool, z :: Char } | T2 { v :: Char } | T3 { x :: Int } | T4 { p :: Float, y :: Bool, x :: Int } | T5 The record update `e { x=e1, y=e2 }` desugars as follows e { x=e1, y=e2 } ===> let { x' = e1; y' = e2 } in case e of T1 _ _ z -> T1 x' y' z T4 p _ _ -> T4 p y' x' The desugared expression is put into an HsExpansion, and we typecheck that. The full details are given in Note [Record Updates] in GHC.Tc.Gen.Expr. Fixes #2595 #3632 #10808 #10856 #16501 #18311 #18802 #21158 #21289 Updates haddock submodule
* Change `Backend` type and remove direct dependencieswip/backend-as-recordNorman Ramsey2022-05-211-4/+3
| | | | | | | | | | | | | | | | | | | With this change, `Backend` becomes an abstract type (there are no more exposed value constructors). Decisions that were formerly made by asking "is the current back end equal to (or different from) this named value constructor?" are now made by interrogating the back end about its properties, which are functions exported by `GHC.Driver.Backend`. There is a description of how to migrate code using `Backend` in the user guide. Clients using the GHC API can find a backdoor to access the Backend datatype in GHC.Driver.Backend.Internal. Bumps haddock submodule. Fixes #20927
* Provide efficient unionMG function for combining two module graphs.Matthew Pickering2022-04-291-4/+25
| | | | | | This function is used by API clients (hls). This supercedes !6922
* Enable eventlog support in all ways by defaultBen Gamari2022-04-271-8/+2
| | | | | | | | | | | | | | | | | Here we deprecate the eventlogging RTS ways and instead enable eventlog support in the remaining ways. This simplifies packaging and reduces GHC compilation times (as we can eliminate two whole compilations of the RTS) while simplifying the end-user story. The trade-off is a small increase in binary sizes in the case that the user does not want eventlogging support, but we think that this is a fine trade-off. This also revealed a latent RTS bug: some files which included `Cmm.h` also assumed that it defined various macros which were in fact defined by `Config.h`, which `Cmm.h` did not include. Fixing this in turn revealed that `StgMiscClosures.cmm` failed to import various spinlock statistics counters, as evidenced by the failed unregisterised build. Closes #18948.
* driver: In oneshot mode, look for interface files in hidirMatthew Pickering2022-04-011-3/+10
| | | | | | | | | | | | | | | | How things should work: * -i is the search path for source files * -hidir explicitly sets the search path for interface files and the output location for interface files. * -odir sets the search path and output location for object files. Before in one shot mode we would look for the interface file in the search locations given by `-i`, but then set the path to be in the `hidir`, so in unusual situations the finder could find an interface file in the `-i` dir but later fail because it tried to read the interface file from the `-hidir`. A bug identified by #20569
* driver: Improve -Wunused-packages error message (and simplify implementation)Matthew Pickering2022-04-011-9/+12
| | | | | | | | | | | | | | | | | | | | | In the past I improved the part of -Wunused-packages which found which packages were used. Now I improve the part which detects which ones were specified. The key innovation is to use the explicitUnits field from UnitState which has the result of resolving the package flags, so we don't need to mess about with the flag arguments from DynFlags anymore. The output now always includes the package name and version (and the flag which exposed it). ``` The following packages were specified via -package or -package-id flags, but were not needed for compilation: - bytestring-0.11.2.0 (exposed by flag -package bytestring) - ghc-9.3 (exposed by flag -package ghc) - process-1.6.13.2 (exposed by flag -package process) ``` Fixes #21307
* Fix all invalid haddock comments in the compilerZubin Duggal2022-03-291-1/+1
| | | | Fixes #20935 and #20924
* hi haddock: Lex and store haddock docs in interface filesZubin Duggal2022-03-233-49/+45
| | | | | | | | | | | | | | | | | | Names appearing in Haddock docstrings are lexed and renamed like any other names appearing in the AST. We currently rename names irrespective of the namespace, so both type and constructor names corresponding to an identifier will appear in the docstring. Haddock will select a given name as the link destination based on its own heuristics. This patch also restricts the limitation of `-haddock` being incompatible with `Opt_KeepRawTokenStream`. The export and documenation structure is now computed in GHC and serialised in .hi files. This can be used by haddock to directly generate doc pages without reparsing or renaming the source. At the moment the operation of haddock is not modified, that's left to a future patch. Updates the haddock submodule with the minimum changes needed.
* driver: Properly add an edge between a .hs and its hs-boot fileMatthew Pickering2022-03-011-5/+3
| | | | | | | | | | | | | | As noted in #21071 we were missing adding this edge so there were situations where the .hs file would get compiled before the .hs-boot file which leads to issues with -j. I fixed this properly by adding the edge in downsweep so the definition of nodeDependencies can be simplified to avoid adding this dummy edge in. There are plenty of tests which seem to have these redundant boot files anyway so no new test. #21094 tracks the more general issue of identifying redundant hs-boot and SOURCE imports.
* Fix longstanding issue with moduleGraphNodes - no hs-boot files caseMatthew Pickering2022-03-011-12/+28
| | | | | | | | | | | | | | | | | | | | In the case when we tell moduleGraphNodes to drop hs-boot files the idea is to collapse hs-boot files into their hs file nodes. In the old code * nodeDependencies changed edges from IsBoot to NonBoot * moduleGraphNodes just dropped boot file nodes The net result is that any dependencies of the hs-boot files themselves were dropped. The correct thing to do is * nodeDependencies changes edges from IsBoot to NonBoot * moduleGraphNodes merges dependencies of IsBoot and NonBoot nodes. The result is a properly quotiented dependency graph which contains no hs-boot files nor hs-boot file edges. Why this didn't cause endless issues when compiling with boot files, we will never know.
* Suggestions due to hlintMatthew Pickering2022-02-245-6/+2
| | | | | It turns out this job hasn't been running for quite a while (perhaps ever) so there are quite a few failures when running the linter locally.
* driver: Remove needsTemplateHaskellOrQQ from ModuleGraphMatthew Pickering2022-02-231-19/+2
| | | | | | | | | | | | | | | | | | | | | | | | | The idea of the needsTemplateHaskellOrQQ query is to check if any of the modules in a module graph need Template Haskell then enable -dynamic-too if necessary. This is quite imprecise though as it will enable -dynamic-too for all modules in the module graph even if only one module uses template haskell, with multiple home units, this is obviously even worse. With -fno-code we already have similar logic to enable code generation just for the modules which are dependeded on my TemplateHaskell modules so we use the same code path to decide whether to enable -dynamic-too rather than using this big hammer. This is part of the larger overall goal of moving as much statically known configuration into the downsweep as possible in order to have fully decided the build plan and all the options before starting to build anything. I also included a fix to #21095, a long standing bug with with the logic which is supposed to enable the external interpreter if we don't have the internal interpreter. Fixes #20696 #21095
* Remove mg_boot field from ModuleGraphMatthew Pickering2022-02-231-11/+1
| | | | | It was unused in the compiler so I have removed it to streamline ModuleGraph.
* Track object file dependencies for TH accurately (#20604)Zubin Duggal2022-02-202-1/+23
| | | | | | | | | | | | | | | | | | | `hscCompileCoreExprHook` is changed to return a list of `Module`s required by a splice. These modules are accumulated in the TcGblEnv (tcg_th_needed_mods). Dependencies on the object files of these modules are recording in the interface. The data structures in `LoaderState` are replaced with more efficient versions to keep track of all the information required. The MultiLayerModulesTH_Make allocations increase slightly but runtime is faster. Fixes #20604 ------------------------- Metric Increase: MultiLayerModulesTH_Make -------------------------
* Tag inference work.Andreas Klebinger2022-02-121-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This does three major things: * Enforce the invariant that all strict fields must contain tagged pointers. * Try to predict the tag on bindings in order to omit tag checks. * Allows functions to pass arguments unlifted (call-by-value). The former is "simply" achieved by wrapping any constructor allocations with a case which will evaluate the respective strict bindings. The prediction is done by a new data flow analysis based on the STG representation of a program. This also helps us to avoid generating redudant cases for the above invariant. StrictWorkers are created by W/W directly and SpecConstr indirectly. See the Note [Strict Worker Ids] Other minor changes: * Add StgUtil module containing a few functions needed by, but not specific to the tag analysis. ------------------------- Metric Decrease: T12545 T18698b T18140 T18923 LargeRecord Metric Increase: LargeRecord ManyAlternatives ManyConstructors T10421 T12425 T12707 T13035 T13056 T13253 T13253-spj T13379 T15164 T18282 T18304 T18698a T1969 T20049 T3294 T4801 T5321FD T5321Fun T783 T9233 T9675 T9961 T19695 WWRec -------------------------
* Fix some notesMatthew Pickering2022-02-083-3/+3
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* compiler: Introduce and use RoughMap for instance environmentsBen Gamari2022-02-041-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here we introduce a new data structure, RoughMap, inspired by the previous `RoughTc` matching mechanism for checking instance matches. This allows [Fam]InstEnv to be implemented as a trie indexed by these RoughTc signatures, reducing the complexity of instance lookup and FamInstEnv merging (done during the family instance conflict test) from O(n) to O(log n). The critical performance improvement currently realised by this patch is in instance matching. In particular the RoughMap mechanism allows us to discount many potential instances which will never match for constraints involving type variables (see Note [Matching a RoughMap]). In realistic code bases matchInstEnv was accounting for 50% of typechecker time due to redundant work checking instances when simplifying instance contexts when deriving instances. With this patch the cost is significantly reduced. The larger constants in InstEnv creation do mean that a few small tests regress in allocations slightly. However, the runtime of T19703 is reduced by a factor of 4. Moreover, the compilation time of the Cabal library is slightly improved. A couple of test cases are included which demonstrate significant improvements in compile time with this patch. This unfortunately does not fix the testcase provided in #19703 but does fix #20933 ------------------------- Metric Decrease: T12425 Metric Increase: T13719 T9872a T9872d hard_hole_fits ------------------------- Co-authored-by: Matthew Pickering <matthewtpickering@gmail.com>
* Fix a few Note inconsistenciesBen Gamari2022-02-011-4/+4
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* Multiple Home UnitsMatthew Pickering2021-12-2812-194/+814
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Multiple home units allows you to load different packages which may depend on each other into one GHC session. This will allow both GHCi and HLS to support multi component projects more naturally. Public Interface ~~~~~~~~~~~~~~~~ In order to specify multiple units, the -unit @⟨filename⟩ flag is given multiple times with a response file containing the arguments for each unit. The response file contains a newline separated list of arguments. ``` ghc -unit @unitLibCore -unit @unitLib ``` where the `unitLibCore` response file contains the normal arguments that cabal would pass to `--make` mode. ``` -this-unit-id lib-core-0.1.0.0 -i -isrc LibCore.Utils LibCore.Types ``` The response file for lib, can specify a dependency on lib-core, so then modules in lib can use modules from lib-core. ``` -this-unit-id lib-0.1.0.0 -package-id lib-core-0.1.0.0 -i -isrc Lib.Parse Lib.Render ``` Then when the compiler starts in --make mode it will compile both units lib and lib-core. There is also very basic support for multiple home units in GHCi, at the moment you can start a GHCi session with multiple units but only the :reload is supported. Most commands in GHCi assume a single home unit, and so it is additional work to work out how to modify the interface to support multiple loaded home units. Options used when working with Multiple Home Units There are a few extra flags which have been introduced specifically for working with multiple home units. The flags allow a home unit to pretend it’s more like an installed package, for example, specifying the package name, module visibility and reexported modules. -working-dir ⟨dir⟩ It is common to assume that a package is compiled in the directory where its cabal file resides. Thus, all paths used in the compiler are assumed to be relative to this directory. When there are multiple home units the compiler is often not operating in the standard directory and instead where the cabal.project file is located. In this case the -working-dir option can be passed which specifies the path from the current directory to the directory the unit assumes to be it’s root, normally the directory which contains the cabal file. When the flag is passed, any relative paths used by the compiler are offset by the working directory. Notably this includes -i and -I⟨dir⟩ flags. -this-package-name ⟨name⟩ This flag papers over the awkward interaction of the PackageImports and multiple home units. When using PackageImports you can specify the name of the package in an import to disambiguate between modules which appear in multiple packages with the same name. This flag allows a home unit to be given a package name so that you can also disambiguate between multiple home units which provide modules with the same name. -hidden-module ⟨module name⟩ This flag can be supplied multiple times in order to specify which modules in a home unit should not be visible outside of the unit it belongs to. The main use of this flag is to be able to recreate the difference between an exposed and hidden module for installed packages. -reexported-module ⟨module name⟩ This flag can be supplied multiple times in order to specify which modules are not defined in a unit but should be reexported. The effect is that other units will see this module as if it was defined in this unit. The use of this flag is to be able to replicate the reexported modules feature of packages with multiple home units. Offsetting Paths in Template Haskell splices ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When using Template Haskell to embed files into your program, traditionally the paths have been interpreted relative to the directory where the .cabal file resides. This causes problems for multiple home units as we are compiling many different libraries at once which have .cabal files in different directories. For this purpose we have introduced a way to query the value of the -working-dir flag to the Template Haskell API. By using this function we can implement a makeRelativeToProject function which offsets a path which is relative to the original project root by the value of -working-dir. ``` import Language.Haskell.TH.Syntax ( makeRelativeToProject ) foo = $(makeRelativeToProject "./relative/path" >>= embedFile) ``` > If you write a relative path in a Template Haskell splice you should use the makeRelativeToProject function so that your library works correctly with multiple home units. A similar function already exists in the file-embed library. The function in template-haskell implements this function in a more robust manner by honouring the -working-dir flag rather than searching the file system. Closure Property for Home Units ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ For tools or libraries using the API there is one very important closure property which must be adhered to: > Any dependency which is not a home unit must not (transitively) depend on a home unit. For example, if you have three packages p, q and r, then if p depends on q which depends on r then it is illegal to load both p and r as home units but not q, because q is a dependency of the home unit p which depends on another home unit r. If you are using GHC by the command line then this property is checked, but if you are using the API then you need to check this property yourself. If you get it wrong you will probably get some very confusing errors about overlapping instances. Limitations of Multiple Home Units ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ There are a few limitations of the initial implementation which will be smoothed out on user demand. * Package thinning/renaming syntax is not supported * More complicated reexports/renaming are not yet supported. * It’s more common to run into existing linker bugs when loading a large number of packages in a session (for example #20674, #20689) * Backpack is not yet supported when using multiple home units. * Dependency chasing can be quite slow with a large number of modules and packages. * Loading wired-in packages as home units is currently not supported (this only really affects GHC developers attempting to load template-haskell). * Barely any normal GHCi features are supported, it would be good to support enough for ghcid to work correctly. Despite these limitations, the implementation works already for nearly all packages. It has been testing on large dependency closures, including the whole of head.hackage which is a total of 4784 modules from 452 packages. Internal Changes ~~~~~~~~~~~~~~~~ * The biggest change is that the HomePackageTable is replaced with the HomeUnitGraph. The HomeUnitGraph is a map from UnitId to HomeUnitEnv, which contains information specific to each home unit. * The HomeUnitEnv contains: - A unit state, each home unit can have different package db flags - A set of dynflags, each home unit can have different flags - A HomePackageTable * LinkNode: A new node type is added to the ModuleGraph, this is used to place the linking step into the build plan so linking can proceed in parralel with other packages being built. * New invariant: Dependencies of a ModuleGraphNode can be completely determined by looking at the value of the node. In order to achieve this, downsweep now performs a more complete job of downsweeping and then the dependenices are recorded forever in the node rather than being computed again from the ModSummary. * Some transitive module calculations are rewritten to use the ModuleGraph which is more efficient. * There is always an active home unit, which simplifies modifying a lot of the existing API code which is unit agnostic (for example, in the driver). The road may be bumpy for a little while after this change but the basics are well-tested. One small metric increase, which we accept and also submodule update to haddock which removes ExtendedModSummary. Closes #10827 ------------------------- Metric Increase: MultiLayerModules ------------------------- Co-authored-by: Fendor <power.walross@gmail.com>
* Properly filter for module visibility in resolvePackageImportMatthew Pickering2021-12-231-1/+1
| | | | | | | | | | | | This completes the fix for #20779 / !7123. Beforehand, the program worked by accident because the two versions of the library happened to be ordered properly (due to how the hashes were computed). In the real world I observed them being the other way around which meant the final lookup failed because we weren't filtering for visibility. I modified the test so that it failed (and it's fixed by this patch).
* package imports: Take into account package visibility when renamingMatthew Pickering2021-12-091-0/+18
| | | | | | | | | | | | In 806e49ae the package imports refactoring code was modified to rename package imports. There was a small oversight which meant the code didn't account for module visibility. This patch fixes that oversight. In general the "lookupPackageName" function is unsafe to use as it doesn't account for package visiblity/thinning/renaming etc, there is just one use in the compiler which would be good to audit. Fixes #20779
* drop instance Semigroup InstalledModuleEnvPepe Iborra2021-11-251-1/+4
| | | | Instead, introduce plusInstalledModuleEnv