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* Add 'docWithStyle' to improve codegenKrzysztof Gogolewski2023-01-111-15/+34
| | | | | | | | | | | | | | This new combinator docWithStyle :: IsOutput doc => doc -> (PprStyle -> SDoc) -> doc let us remove the need for code to be polymorphic in HDoc when not used in code style. Metric Decrease: ManyConstructors T13035 T1969
* Add support for sized literals in the bytecode interpreter.Luite Stegeman2023-01-061-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The bytecode interpreter only has branching instructions for word-sized values. These are used for pattern matching. Branching instructions for other types (e.g. Int16# or Word8#) weren't needed, since unoptimized Core or STG never requires branching on types like this. It's now possible for optimized STG to reach the bytecode generator (e.g. fat interface files or certain compiler flag combinations), which requires dealing with various sized literals in branches. This patch improves support for generating bytecode from optimized STG by adding the following new bytecode instructions: TESTLT_I64 TESTEQ_I64 TESTLT_I32 TESTEQ_I32 TESTLT_I16 TESTEQ_I16 TESTLT_I8 TESTEQ_I8 TESTLT_W64 TESTEQ_W64 TESTLT_W32 TESTEQ_W32 TESTLT_W16 TESTEQ_W16 TESTLT_W8 TESTEQ_W8 Fixes #21945
* Scrub some partiality in `GHC.Cmm.Info.Build`: `doSRTs` takes a `[(CAFSet, ↵M Farkas-Dyck2022-12-201-0/+4
| | | | CmmDecl)]` but truly wants a `[(CAFSet, CmmStatics)]`.
* Properly cast values when writing/reading unboxed sums.Andreas Klebinger2022-11-301-0/+2
| | | | | | | Unboxed sums might store a Int8# value as Int64#. This patch makes sure we keep track of the actual value type. See Note [Casting slot arguments] for the details.
* Change printing of sized literals to match the proposalKrzysztof Gogolewski2022-11-291-8/+8
| | | | | | | | Literals in Core were printed as e.g. 0xFF#16 :: Int16#. The proposal 451 now specifies syntax 0xFF#Int16. This change affects the Core printer only - more to be done later. Part of #21422.
* Print unticked promoted data constructors (#20531)Vladislav Zavialov2022-11-251-21/+62
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before this patch, GHC unconditionally printed ticks before promoted data constructors: ghci> type T = True -- unticked (user-written) ghci> :kind! T T :: Bool = 'True -- ticked (compiler output) After this patch, GHC prints ticks only when necessary: ghci> type F = False -- unticked (user-written) ghci> :kind! F F :: Bool = False -- unticked (compiler output) ghci> data False -- introduce ambiguity ghci> :kind! F F :: Bool = 'False -- ticked by necessity (compiler output) The old behavior can be enabled by -fprint-redundant-promotion-ticks. Summary of changes: * Rename PrintUnqualified to NamePprCtx * Add QueryPromotionTick to it * Consult the GlobalRdrEnv to decide whether to print a tick (see mkPromTick) * Introduce -fprint-redundant-promotion-ticks Co-authored-by: Artyom Kuznetsov <hi@wzrd.ht>
* Check if the SDoc starts with a single quote (#22488)Vladislav Zavialov2022-11-231-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes pretty-printing of character literals inside promoted lists and tuples. When we pretty-print a promoted list or tuple whose first element starts with a single quote, we want to add a space between the opening bracket and the element: '[True] -- ok '[ 'True] -- ok '['True] -- not ok If we don't add the space, we accidentally produce a character literal '['. Before this patch, pprSpaceIfPromotedTyCon inspected the type as an AST and tried to guess if it would be rendered with a single quote. However, it missed the case when the inner type was itself a character literal: '[ 'x'] -- ok '['x'] -- not ok Instead of adding this particular case, I opted for a more future-proof solution: check the SDoc directly. This way we can detect if the single quote is actually there instead of trying to predict it from the AST. The new function is called spaceIfSingleQuote.
* Use a more efficient printer for code generation (#21853)Krzysztof Gogolewski2022-11-111-116/+424
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Export pprTrace and friends from GHC.Prelude.Andreas Klebinger2022-11-031-1/+1
| | | | | Introduces GHC.Prelude.Basic which can be used in modules which are a dependency of the ppr code.
* Minor SDoc-related cleanupKrzysztof Gogolewski2022-10-281-14/+1
| | | | | | | | | | | * Rename pprCLabel to pprCLabelStyle, and use the name pprCLabel for a function using CStyle (analogous to pprAsmLabel) * Move LabelStyle to the CLabel module, it no longer needs to be in Outputable. * Move calls to 'text' right next to literals, to make sure the text/str rule is triggered. * Remove FastString/String roundtrip in Tc.Deriv.Generate * Introduce showSDocForUser', which abstracts over a pattern in GHCi.UI
* Scrub various partiality involving lists (again).M Farkas-Dyck2022-10-191-1/+2
| | | | Lets us avoid some use of `head` and `tail`, and some panics.
* Minor refactor around OutputableKrzysztof Gogolewski2022-09-221-3/+3
| | | | | | | * Replace 'text . show' and 'ppr' with 'int'. * Remove Outputable.hs-boot, no longer needed * Use pprWithCommas * Factor out instructions in AArch64 codegen
* Fix typosKrzysztof Gogolewski2022-09-141-1/+1
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* Fix typosEric Lindblad2022-09-141-2/+2
| | | | | | | This fixes various typos and spelling mistakes in the compiler. Fixes #21891
* Remove Outputable Char instanceKrzysztof Gogolewski2022-09-071-2/+2
| | | | | Use 'text' instead of 'ppr'. Using 'ppr' on the list "hello" rendered as "h,e,l,l,o".
* Minor cleanupKrzysztof Gogolewski2022-09-011-2/+0
| | | | | | | | | - Remove mkHeteroCoercionType, sdocImpredicativeTypes, isStateType (unused), isCoVar_maybe (duplicated by getCoVar_maybe) - Replace a few occurrences of voidPrimId with (# #). void# is a deprecated synonym for the unboxed tuple. - Use showSDoc in :show linker. This makes it consistent with the other :show commands
* Remove label style from printing contextKrzysztof Gogolewski2022-08-261-10/+6
| | | | | | | | | | | | Previously, the SDocContext used for code generation contained information whether the labels should use Asm or C style. However, at every individual call site, this is known statically. This removes the parameter to 'PprCode' and replaces every 'pdoc' used to print a label in code style with 'pprCLabel' or 'pprAsmLabel'. The OutputableP instance is now used only for dumps. The output of T15155 changes, it now uses the Asm style (which is faithful to what actually happens).
* Add -dsuppress-coercion-types to make coercions even smaller.Andreas Klebinger2022-08-021-0/+2
| | | | | Instead of `` `cast` <Co:11> :: (Some -> Really -> Large Type)`` simply print `` `cast` <Co:11> :: ... ``
* Refactor ModuleName to L.H.S.Module.Nameromes2022-07-031-1/+13
| | | | | | | | | | | | | | | 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.ImpExpromes2022-07-031-1/+2
| | | | | | | | | | | 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.Sromes2022-07-031-1/+1
| | | | | | | | | 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
* Don't mark lambda binders as OtherConAndreas Klebinger2022-06-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We used to put OtherCon unfoldings on lambda binders of workers and sometimes also join points/specializations with with the assumption that since the wrapper would force these arguments once we execute the RHS they would indeed be in WHNF. This was wrong for reasons detailed in #21472. So now we purge evaluated unfoldings from *all* lambda binders. This fixes #21472, but at the cost of sometimes not using as efficient a calling convention. It can also change inlining behaviour as some occurances will no longer look like value arguments when they did before. As consequence we also change how we compute CBV information for arguments slightly. We now *always* determine the CBV convention for arguments during tidy. Earlier in the pipeline we merely mark functions as candidates for having their arguments treated as CBV. As before the process is described in the relevant notes: Note [CBV Function Ids] Note [Attaching CBV Marks to ids] Note [Never put `OtherCon` unfoldigns on lambda binders] ------------------------- Metric Decrease: T12425 T13035 T18223 T18223 T18923 MultiLayerModulesTH_OneShot Metric Increase: WWRec -------------------------
* Adjust flags for pprTraceSimon Peyton Jones2022-05-171-1/+15
| | | | | | | | | | | | | | | | We were using defaultSDocContext for pprTrace, which suppresses lots of useful infomation. This small MR adds GHC.Utils.Outputable.traceSDocContext and uses it for pprTrace and pprTraceUserWarning. traceSDocContext is a global, and hence not influenced by flags, but that seems unavoidable. But I made the sdocPprDebug bit controlled by unsafeHasPprDebug, since we have the latter for exactly this purpose. Fixes #21569
* Fix printing of brackets in multiplicities (#20315)jackohughes2022-05-131-5/+1
| | | | | | | | | Change mulArrow to allow for printing of correct application precedence where necessary and update callers of mulArrow to reflect this. As part of this, move mulArrow from GHC/Utils/Outputtable to GHC/Iface/Type. Fixes #20315
* Rename [] to List (#21294)Vladislav Zavialov2022-04-071-0/+2
| | | | | | | | | | | | | This patch implements a small part of GHC Proposal #475. The key change is in GHC.Types: - data [] a = [] | a : [a] + data List a = [] | a : List a And the rest of the patch makes sure that List is pretty-printed as [] in various contexts. Updates the haddock submodule.
* Fix isLiftedType_maybe and handle falloutsheaf2022-03-141-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As #20837 pointed out, `isLiftedType_maybe` returned `Just False` in many situations where it should return `Nothing`, because it didn't take into account type families or type variables. In this patch, we fix this issue. We rename `isLiftedType_maybe` to `typeLevity_maybe`, which now returns a `Levity` instead of a boolean. We now return `Nothing` for types with kinds of the form `TYPE (F a1 ... an)` for a type family `F`, as well as `TYPE (BoxedRep l)` where `l` is a type variable. This fix caused several other problems, as other parts of the compiler were relying on `isLiftedType_maybe` returning a `Just` value, and were now panicking after the above fix. There were two main situations in which panics occurred: 1. Issues involving the let/app invariant. To uphold that invariant, we need to know whether something is lifted or not. If we get an answer of `Nothing` from `isLiftedType_maybe`, then we don't know what to do. As this invariant isn't particularly invariant, we can change the affected functions to not panic, e.g. by behaving the same in the `Just False` case and in the `Nothing` case (meaning: no observable change in behaviour compared to before). 2. Typechecking of data (/newtype) constructor patterns. Some programs involving patterns with unknown representations were accepted, such as T20363. Now that we are stricter, this caused further issues, culminating in Core Lint errors. However, the behaviour was incorrect the whole time; the incorrectness only being revealed by this change, not triggered by it. This patch fixes this by overhauling where the representation polymorphism involving pattern matching are done. Instead of doing it in `tcMatches`, we instead ensure that the `matchExpected` functions such as `matchExpectedFunTys`, `matchActualFunTySigma`, `matchActualFunTysRho` allow return argument pattern types which have a fixed RuntimeRep (as defined in Note [Fixed RuntimeRep]). This ensures that the pattern matching code only ever handles types with a known runtime representation. One exception was that patterns with an unknown representation type could sneak in via `tcConPat`, which points to a missing representation-polymorphism check, which this patch now adds. This means that we now reject the program in #20363, at least until we implement PHASE 2 of FixedRuntimeRep (allowing type families in RuntimeRep positions). The aforementioned refactoring, in which checks have been moved to `matchExpected` functions, is a first step in implementing PHASE 2 for patterns. Fixes #20837
* Fix type check error message grammar (fixes #20122)CarrieMY2021-07-281-1/+20
| | | | Remove trailing spaces
* Put tracing functions into their own moduleSylvain Henry2021-06-221-0/+8
| | | | | | | | Now that Outputable is independent of DynFlags, we can put tracing functions using SDocs into their own module that doesn't transitively depend on any GHC.Driver.* module. A few modules needed to be moved to avoid loops in DEBUG mode.
* Driver Rework PatchMatthew Pickering2021-06-031-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patch comprises of four different but closely related ideas. The net result is fixing a large number of open issues with the driver whilst making it simpler to understand. 1. Use the hash of the source file to determine whether the source file has changed or not. This makes the recompilation checking more robust to modern build systems which are liable to copy files around changing their modification times. 2. Remove the concept of a "stable module", a stable module was one where the object file was older than the source file, and all transitive dependencies were also stable. Now we don't rely on the modification time of the source file, the notion of stability is moot. 3. Fix TH/plugin recompilation after the removal of stable modules. The TH recompilation check used to rely on stable modules. Now there is a uniform and simple way, we directly track the linkables which were loaded into the interpreter whilst compiling a module. This is an over-approximation but more robust wrt package dependencies changing. 4. Fix recompilation checking for dynamic object files. Now we actually check if the dynamic object file exists when compiling with -dynamic-too Fixes #19774 #19771 #19758 #17434 #11556 #9121 #8211 #16495 #7277 #16093
* Make GHC.Runtime.Interpreter independent of GHC.DriverSylvain Henry2021-04-301-0/+9
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* Enhance pretty-printing perfSylvain Henry2021-04-101-15/+63
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A few refactorings made after looking at Core/STG * Use Doc instead of SDoc in pprASCII to avoid passing the SDocContext that is never used. * Inline every SDoc wrappers in GHC.Utils.Outputable to expose Doc constructs * Add text/[] rule for empty strings (i.e., text "") * Use a single occurrence of pprGNUSectionHeader * Use bangs on Platform parameters and some others Metric Decrease: ManyAlternatives ManyConstructors T12707 T13035 T13379 T18698a T18698b T1969 T3294 T4801 T5321FD T783
* GHC Exactprint main commitAlan Zimmerman2021-03-201-2/+5
| | | | | | | | Metric Increase: T10370 parsing001 Updates haddock submodule
* Make proper fixed-width number literalsSylvain Henry2021-01-021-13/+23
| | | | | | | | (Progress towards #11953, #17377, #17375) Besides being nicer to use, this also will allow for better constant folding for the fixed-width types, on par with what `Int#` and `Word#` have today.
* Optimize dumping of consecutive whitespace.wip/andreask/opt_dumpsAndreas Klebinger2020-12-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The naive way of putting out n characters of indent would be something like `hPutStr hdl (replicate n ' ')`. However this is quite inefficient as we allocate an absurd number of strings consisting of simply spaces as we don't cache them. To improve on this we now track if we can simply write ascii spaces via hPutBuf instead. This is the case when running with -ddump-to-file where we force the encoding to be UTF8. This avoids both the cost of going through encoding as well as avoiding allocation churn from all the white space. Instead we simply use hPutBuf on a preallocated unlifted string. When dumping stg like this: > nofib/spectral/simple/Main.hs -fforce-recomp -ddump-stg-final -ddump-to-file -c +RTS -s Allocations went from 1,778 MB to 1,702MB. About a 4% reduction of allocation! I did not measure the difference in runtime but expect it to be similar. Bumps the haddock submodule since the interface of GHC's Pretty slightly changed. ------------------------- Metric Decrease: T12227 -------------------------
* Cmm.Sink: Optimize retaining of assignments, live sets.Andreas Klebinger2020-12-081-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | Sinking requires us to track live local regs after each cmm statement. We used to do this via "Set LocalReg". However we can replace this with a solution based on IntSet which is overall more efficient without losing much. The thing we lose is width of the variables, which isn't used by the sinking pass anyway. I also reworked how we keep assignments to regs mentioned in skipped assignments. I put the details into Note [Keeping assignemnts mentioned in skipped RHSs]. The gist of it is instead of keeping track of it via the use count which is a `IntMap Int` we now use the live regs set (IntSet) which is quite a bit faster. I think it also matches the semantics a lot better. The skipped (not discarded) assignment does in fact keep the regs on it's rhs alive so keeping track of this in the live set seems like the clearer solution as well. Improves allocations for T3294 by yet another 1%.
* [Sized Cmm] properly retain sizes.Moritz Angermann2020-11-261-5/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | This replaces all Word<N> = W<N># Word# and Int<N> = I<N># Int# with Word<N> = W<N># Word<N># and Int<N> = I<N># Int<N>#, thus providing us with properly sized primitives in the codegenerator instead of pretending they are all full machine words. This came up when implementing darwinpcs for arm64. The darwinpcs reqires us to pack function argugments in excess of registers on the stack. While most procedure call standards (pcs) assume arguments are just passed in 8 byte slots; and thus the caller does not know the exact signature to make the call, darwinpcs requires us to adhere to the prototype, and thus have the correct sizes. If we specify CInt in the FFI call, it should correspond to the C int, and not just be Word sized, when it's only half the size. This does change the expected output of T16402 but the new result is no less correct as it eliminates the narrowing (instead of the `and` as was previously done). Bumps the array, bytestring, text, and binary submodules. Co-Authored-By: Ben Gamari <ben@well-typed.com> Metric Increase: T13701 T14697
* Demand: Interleave usage and strictness demands (#18903)Sebastian Graf2020-11-201-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As outlined in #18903, interleaving usage and strictness demands not only means a more compact demand representation, but also allows us to express demands that we weren't easily able to express before. Call demands are *relative* in the sense that a call demand `Cn(cd)` on `g` says "`g` is called `n` times. *Whenever `g` is called*, the result is used according to `cd`". Example from #18903: ```hs h :: Int -> Int h m = let g :: Int -> (Int,Int) g 1 = (m, 0) g n = (2 * n, 2 `div` n) {-# NOINLINE g #-} in case m of 1 -> 0 2 -> snd (g m) _ -> uncurry (+) (g m) ``` Without the interleaved representation, we would just get `L` for the strictness demand on `g`. Now we are able to express that whenever `g` is called, its second component is used strictly in denoting `g` by `1C1(P(1P(U),SP(U)))`. This would allow Nested CPR to unbox the division, for example. Fixes #18903. While fixing regressions, I also discovered and fixed #18957. Metric Decrease: T13253-spj
* Remove unnecessary gender from comments/docsRichard Eisenberg2020-10-291-2/+2
| | | | | | | 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.
* Split GHC.Driver.TypesSylvain Henry2020-10-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Remove pdocPrecSylvain Henry2020-10-191-6/+0
| | | | | | pdocPrec was only used in GHC.Cmm.DebugBlock.pprUnwindExpr, so remove it. OutputableP becomes a one-function class which might be better for performance.
* Fix pretty-printing of the mult-polymorphic arrowVladislav Zavialov2020-10-011-1/+1
| | | | A follow-up to !4020 (5830a12c46e7227c276a8a71213057595ee4fc04)
* New linear types syntax: a %p -> b (#18459)Vladislav Zavialov2020-09-291-1/+1
| | | | | | Implements GHC Proposal #356 Updates the haddock submodule.
* Remove sdocWithDynFlags (fix #10143)Sylvain Henry2020-09-231-11/+2
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* Refactor CLabel pretty-printingSylvain Henry2020-09-231-10/+16
| | | | | | | | | | * Don't depend on the selected backend to know if we print Asm or C labels: we already have PprStyle to determine this. Moreover even when a native backend is used (NCG, LLVM) we may want to C headers containing pretty-printed labels, so it wasn't a good predicate anyway. * Make pretty-printing code clearer and avoid partiality
* Remove pprPrec from Outputable (unused)Sylvain Henry2020-09-171-8/+1
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* Add note about OutputablePSylvain Henry2020-09-171-9/+108
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* Generalize OutputablePSylvain Henry2020-09-171-20/+21
| | | | | Add a type parameter for the environment required by OutputableP. It avoids tying Platform with OutputableP.
* Introduce OutputablePSylvain Henry2020-09-171-2/+47
| | | | | | | | | | | | | | | | | | | | | | | | | Some types need a Platform value to be pretty-printed: CLabel, Cmm types, instructions, etc. Before this patch they had an Outputable instance and the Platform value was obtained via sdocWithDynFlags. It meant that the *renderer* of the SDoc was responsible of passing the appropriate Platform value (e.g. via the DynFlags given to showSDoc). It put the burden of passing the Platform value on the renderer while the generator of the SDoc knows the Platform it is generating the SDoc for and there is no point passing a different Platform at rendering time. With this patch, we introduce a new OutputableP class: class OutputableP a where pdoc :: Platform -> a -> SDoc With this class we still have some polymorphism as we have with `ppr` (i.e. we can use `pdoc` on a variety of types instead of having a dedicated `pprXXX` function for each XXX type). One step closer removing `sdocWithDynFlags` (#10143) and supporting several platforms (#14335).
* Remove "Ord FastString" instanceSylvain Henry2020-09-011-0/+6
| | | | | | | | | | | | | | | | | | | FastStrings can be compared in 2 ways: by Unique or lexically. We don't want to bless one particular way with an "Ord" instance because it leads to bugs (#18562) or to suboptimal code (e.g. using lexical comparison while a Unique comparison would suffice). UTF-8 encoding has the advantage that sorting strings by their encoded bytes also sorts them by their Unicode code points, without having to decode the actual code points. BUT GHC uses Modified UTF-8 which diverges from UTF-8 by encoding \0 as 0xC080 instead of 0x00 (to avoid null bytes in the middle of a String so that the string can still be null-terminated). This patch adds a new `utf8CompareShortByteString` function that performs sorting by bytes but that also takes Modified UTF-8 into account. It is much more performant than decoding the strings into [Char] to perform comparisons (which we did in the previous patch). Bump haddock submodule
* Refactor UnitId pretty-printingSylvain Henry2020-08-261-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we pretty-print a UnitId for the user, we try to map it back to its origin package name, version and component to print "package-version:component" instead of some hash. The UnitId type doesn't carry these information, so we have to look into a UnitState to find them. This is why the Outputable instance of UnitId used `sdocWithDynFlags` in order to access the `unitState` field of DynFlags. This is wrong for several reasons: 1. The DynFlags are accessed when the message is printed, not when it is generated. So we could imagine that the unitState may have changed in-between. Especially if we want to allow unit unloading. 2. We want GHC to support several independent sessions at once, hence several UnitState. The current approach supposes there is a unique UnitState as a UnitId doesn't indicate which UnitState to use. See the Note [Pretty-printing UnitId] in GHC.Unit for the new approach implemented by this patch. One step closer to remove `sdocDynFlags` field from `SDocContext` (#10143). Fix #18124. Also fix some Backpack code to use SDoc instead of String.
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