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2020-02-06Do not create nested quantified constraintswip/t17202Richard Eisenberg
Previously, we would accidentally make constraints like forall a. C a => forall b. D b => E a b c as we traversed superclasses. No longer! This patch also expands Note [Eagerly expand given superclasses] to work over quantified constraints; necessary for T16502b. Close #17202 and #16502. test cases: typecheck/should_compile/T{17202,16502{,b}}
2020-02-05gitlab-ci: Allow Windows builds to fail againBen Gamari
Due to T7702 and the process issues described in #17777.
2020-02-05Add regression test for #17773Ryan Scott
2020-02-05Remove CafInfo-related code from STG lambda lift passÖmer Sinan Ağacan
After c846618ae0 we don't have accurate CafInfos for Ids in the current module and we're free to introduce new CAFFY or non-CAFFY bindings or change CafInfos of existing binders; so no we no longer need to maintain CafInfos in Core or STG passes.
2020-02-05testlib: Extend existing *_opts in extra_*_optsÖmer Sinan Ağacan
Previously we'd override the existing {run,hc} opts in extra_{run,hc}_opts, which caused flakiness in T1969, see #17712. extra_{run,hc}_opts now extends {run,hc} opts, instead of overriding. Also we shrank the allocation area for T1969 in order to increase residency sampling frequency. Fixes #17712
2020-02-05PmCheck: Record type constraints arising from existentials in `PmCoreCt`sSebastian Graf
In #17703 (a follow-up of !2192), we established that contrary to my belief, type constraints arising from existentials in code like ```hs data Ex where Ex :: a -> Ex f _ | let x = Ex @Int 15 = case x of Ex -> ... ``` are in fact useful. This commit makes a number of refactorings and improvements to comments, but fundamentally changes `addCoreCt.core_expr` to record the type constraint `a ~ Int` in addition to `x ~ Ex @a y` and `y ~ 15`. Fixes #17703.
2020-02-04Delete some superfluous helper functions in HscMainJohn Ericson
The driver code is some of the nastiest in GHC, and I am worried about being able to untangle all the tech debt. In `HscMain` we have a number of helpers which are either not-used or little used. I delete them so we can reduce cognative load, distilling the essential complexity away from the cruft.
2020-02-04fixup! fixup! Do not build StgCRunAsm.S for unregisterised buildsStefan Schulze Frielinghaus
2020-02-04Do not build StgCRunAsm.S for unregisterised buildsStefan Schulze Frielinghaus
For unregisterised builds StgRun/StgReturn are implemented via a mini interpreter in StgCRun.c and therefore would collide with the implementations in StgCRunAsm.S.
2020-02-04Refactor HscMain.finishJohn Ericson
I found the old control flow a bit hard to follow; I rewrote it to first decide whether to desugar, and then use that choice when computing whether to simplify / what sort of interface file to write. I hope eventually we will always write post-tc interface files, which will make the logic of this function even simpler, and continue the thrust of this refactor.
2020-02-04Fix docs for FrontendResultJohn Ericson
Other variant was removed in ac1a379363618a6f2f17fff65ce9129164b6ef30 but docs were no changed.
2020-02-01Improve/fix -fcatch-bottoms documentationÖmer Sinan Ağacan
Old documentation suggests that -fcatch-bottoms only adds a default alternative to bottoming case expression, but that's not true. We use a very simplistic "is exhaustive" check and add default alternatives to any case expression that does not cover all constructors of the type. In case of GADTs this simple check assumes all constructors should be covered, even the ones ruled out by the type of the scrutinee. Update the documentation to reflect this. (Originally noticed in #17648) [ci skip]
2020-02-01rts/M32Alloc: Don't attempt to unmap non-existent pagesBen Gamari
The m32 allocator's `pages` list may contain NULLs in the case that the page was flushed. Some `munmap` implementations (e.g. FreeBSD's) don't like it if we pass them NULL. Don't do that.
2020-02-01Fix scoping of TyCon binders in TcTyClsDeclsSimon Peyton Jones
This patch fixes #17566 by refactoring the way we decide the final identity of the tyvars in the TyCons of a possibly-recursive nest of type and class decls, possibly with associated types. It's all laid out in Note [Swizzling the tyvars before generaliseTcTyCon] Main changes: * We have to generalise each decl (with its associated types) all at once: TcTyClsDecls.generaliseTyClDecl * The main new work is done in TcTyClsDecls.swizzleTcTyConBndrs * The mysterious TcHsSyn.zonkRecTyVarBndrs dies altogether Other smaller things: * A little refactoring, moving bindTyClTyVars from tcTyClDecl1 to tcDataDefn, tcSynRhs, etc. Clearer, reduces the number of parameters * Reduce the amount of swizzling required. Specifically, bindExplicitTKBndrs_Q_Tv doesn't need to clone a new Name for the TyVarTv, and not cloning means that in the vasly common case, swizzleTyConBndrs is a no-op In detail: Rename newTyVarTyVar --> cloneTyVarTyVar Add newTyVarTyTyVar that doesn't clone Use the non-cloning newTyVarTyVar in bindExplicitTKBndrs_Q_Tv Rename newFlexiKindedTyVarTyVar --> cloneFlexiKindedTyVarTyVar * Define new utility function and use it HsDecls.familyDeclName :: FamilyDecl (GhcPass p) -> IdP (GhcPass p) Updates haddock submodule.
2020-02-01Improve pretty-printing for TyConBindersSimon Peyton Jones
In particular, show their kinds.
2020-02-01Improve skolemisationSimon Peyton Jones
This patch avoids skolemiseUnboundMetaTyVar making up a fresh Name when it doesn't need to. See Note [Skolemising and identity] Improves error messsages for partial type signatures.
2020-01-31A few optimizations in STG and Cmm parts:Andreas Klebinger
(Guided by the profiler output) - Add a few bang patterns, INLINABLE annotations, and a seqList in a few places in Cmm and STG parts. - Do not add external variables as dependencies in STG dependency analysis (GHC.Stg.DepAnal).
2020-01-31Do CafInfo/SRT analysis in CmmÖmer Sinan Ağacan
This patch removes all CafInfo predictions and various hacks to preserve predicted CafInfos from the compiler and assigns final CafInfos to interface Ids after code generation. SRT analysis is extended to support static data, and Cmm generator is modified to allow generating static_link fields after SRT analysis. This also fixes `-fcatch-bottoms`, which introduces error calls in case expressions in CorePrep, which runs *after* CoreTidy (which is where we decide on CafInfos) and turns previously non-CAFFY things into CAFFY. Fixes #17648 Fixes #9718 Evaluation ========== NoFib ----- Boot with: `make boot mode=fast` Run: `make mode=fast EXTRA_RUNTEST_OPTS="-cachegrind" NoFibRuns=1` -------------------------------------------------------------------------------- Program Size Allocs Instrs Reads Writes -------------------------------------------------------------------------------- CS -0.0% 0.0% -0.0% -0.0% -0.0% CSD -0.0% 0.0% -0.0% -0.0% -0.0% FS -0.0% 0.0% -0.0% -0.0% -0.0% S -0.0% 0.0% -0.0% -0.0% -0.0% VS -0.0% 0.0% -0.0% -0.0% -0.0% VSD -0.0% 0.0% -0.0% -0.0% -0.5% VSM -0.0% 0.0% -0.0% -0.0% -0.0% anna -0.1% 0.0% -0.0% -0.0% -0.0% ansi -0.0% 0.0% -0.0% -0.0% -0.0% atom -0.0% 0.0% -0.0% -0.0% -0.0% awards -0.0% 0.0% -0.0% -0.0% -0.0% banner -0.0% 0.0% -0.0% -0.0% -0.0% bernouilli -0.0% 0.0% -0.0% -0.0% -0.0% binary-trees -0.0% 0.0% -0.0% -0.0% -0.0% boyer -0.0% 0.0% -0.0% -0.0% -0.0% boyer2 -0.0% 0.0% -0.0% -0.0% -0.0% bspt -0.0% 0.0% -0.0% -0.0% -0.0% cacheprof -0.0% 0.0% -0.0% -0.0% -0.0% calendar -0.0% 0.0% -0.0% -0.0% -0.0% cichelli -0.0% 0.0% -0.0% -0.0% -0.0% circsim -0.0% 0.0% -0.0% -0.0% -0.0% clausify -0.0% 0.0% -0.0% -0.0% -0.0% comp_lab_zift -0.0% 0.0% -0.0% -0.0% -0.0% compress -0.0% 0.0% -0.0% -0.0% -0.0% compress2 -0.0% 0.0% -0.0% -0.0% -0.0% constraints -0.0% 0.0% -0.0% -0.0% -0.0% cryptarithm1 -0.0% 0.0% -0.0% -0.0% -0.0% cryptarithm2 -0.0% 0.0% -0.0% -0.0% -0.0% cse -0.0% 0.0% -0.0% -0.0% -0.0% digits-of-e1 -0.0% 0.0% -0.0% -0.0% -0.0% digits-of-e2 -0.0% 0.0% -0.0% -0.0% -0.0% dom-lt -0.0% 0.0% -0.0% -0.0% -0.0% eliza -0.0% 0.0% -0.0% -0.0% -0.0% event -0.0% 0.0% -0.0% -0.0% -0.0% exact-reals -0.0% 0.0% -0.0% -0.0% -0.0% exp3_8 -0.0% 0.0% -0.0% -0.0% -0.0% expert -0.0% 0.0% -0.0% -0.0% -0.0% fannkuch-redux -0.0% 0.0% -0.0% -0.0% -0.0% fasta -0.0% 0.0% -0.0% -0.0% -0.0% fem -0.0% 0.0% -0.0% -0.0% -0.0% fft -0.0% 0.0% -0.0% -0.0% -0.0% fft2 -0.0% 0.0% -0.0% -0.0% -0.0% fibheaps -0.0% 0.0% -0.0% -0.0% -0.0% fish -0.0% 0.0% -0.0% -0.0% -0.0% fluid -0.1% 0.0% -0.0% -0.0% -0.0% fulsom -0.0% 0.0% -0.0% -0.0% -0.0% gamteb -0.0% 0.0% -0.0% -0.0% -0.0% gcd -0.0% 0.0% -0.0% -0.0% -0.0% gen_regexps -0.0% 0.0% -0.0% -0.0% -0.0% genfft -0.0% 0.0% -0.0% -0.0% -0.0% gg -0.0% 0.0% -0.0% -0.0% -0.0% grep -0.0% 0.0% -0.0% -0.0% -0.0% hidden -0.0% 0.0% -0.0% -0.0% -0.0% hpg -0.1% 0.0% -0.0% -0.0% -0.0% ida -0.0% 0.0% -0.0% -0.0% -0.0% infer -0.0% 0.0% -0.0% -0.0% -0.0% integer -0.0% 0.0% -0.0% -0.0% -0.0% integrate -0.0% 0.0% -0.0% -0.0% -0.0% k-nucleotide -0.0% 0.0% -0.0% -0.0% -0.0% kahan -0.0% 0.0% -0.0% -0.0% -0.0% knights -0.0% 0.0% -0.0% -0.0% -0.0% lambda -0.0% 0.0% -0.0% -0.0% -0.0% last-piece -0.0% 0.0% -0.0% -0.0% -0.0% lcss -0.0% 0.0% -0.0% -0.0% -0.0% life -0.0% 0.0% -0.0% -0.0% -0.0% lift -0.0% 0.0% -0.0% -0.0% -0.0% linear -0.1% 0.0% -0.0% -0.0% -0.0% listcompr -0.0% 0.0% -0.0% -0.0% -0.0% listcopy -0.0% 0.0% -0.0% -0.0% -0.0% maillist -0.0% 0.0% -0.0% -0.0% -0.0% mandel -0.0% 0.0% -0.0% -0.0% -0.0% mandel2 -0.0% 0.0% -0.0% -0.0% -0.0% mate -0.0% 0.0% -0.0% -0.0% -0.0% minimax -0.0% 0.0% -0.0% -0.0% -0.0% mkhprog -0.0% 0.0% -0.0% -0.0% -0.0% multiplier -0.0% 0.0% -0.0% -0.0% -0.0% n-body -0.0% 0.0% -0.0% -0.0% -0.0% nucleic2 -0.0% 0.0% -0.0% -0.0% -0.0% para -0.0% 0.0% -0.0% -0.0% -0.0% paraffins -0.0% 0.0% -0.0% -0.0% -0.0% parser -0.1% 0.0% -0.0% -0.0% -0.0% parstof -0.1% 0.0% -0.0% -0.0% -0.0% pic -0.0% 0.0% -0.0% -0.0% -0.0% pidigits -0.0% 0.0% -0.0% -0.0% -0.0% power -0.0% 0.0% -0.0% -0.0% -0.0% pretty -0.0% 0.0% -0.3% -0.4% -0.4% primes -0.0% 0.0% -0.0% -0.0% -0.0% primetest -0.0% 0.0% -0.0% -0.0% -0.0% prolog -0.0% 0.0% -0.0% -0.0% -0.0% puzzle -0.0% 0.0% -0.0% -0.0% -0.0% queens -0.0% 0.0% -0.0% -0.0% -0.0% reptile -0.0% 0.0% -0.0% -0.0% -0.0% reverse-complem -0.0% 0.0% -0.0% -0.0% -0.0% rewrite -0.0% 0.0% -0.0% -0.0% -0.0% rfib -0.0% 0.0% -0.0% -0.0% -0.0% rsa -0.0% 0.0% -0.0% -0.0% -0.0% scc -0.0% 0.0% -0.3% -0.5% -0.4% sched -0.0% 0.0% -0.0% -0.0% -0.0% scs -0.0% 0.0% -0.0% -0.0% -0.0% simple -0.1% 0.0% -0.0% -0.0% -0.0% solid -0.0% 0.0% -0.0% -0.0% -0.0% sorting -0.0% 0.0% -0.0% -0.0% -0.0% spectral-norm -0.0% 0.0% -0.0% -0.0% -0.0% sphere -0.0% 0.0% -0.0% -0.0% -0.0% symalg -0.0% 0.0% -0.0% -0.0% -0.0% tak -0.0% 0.0% -0.0% -0.0% -0.0% transform -0.0% 0.0% -0.0% -0.0% -0.0% treejoin -0.0% 0.0% -0.0% -0.0% -0.0% typecheck -0.0% 0.0% -0.0% -0.0% -0.0% veritas -0.0% 0.0% -0.0% -0.0% -0.0% wang -0.0% 0.0% -0.0% -0.0% -0.0% wave4main -0.0% 0.0% -0.0% -0.0% -0.0% wheel-sieve1 -0.0% 0.0% -0.0% -0.0% -0.0% wheel-sieve2 -0.0% 0.0% -0.0% -0.0% -0.0% x2n1 -0.0% 0.0% -0.0% -0.0% -0.0% -------------------------------------------------------------------------------- Min -0.1% 0.0% -0.3% -0.5% -0.5% Max -0.0% 0.0% -0.0% -0.0% -0.0% Geometric Mean -0.0% -0.0% -0.0% -0.0% -0.0% -------------------------------------------------------------------------------- Program Size Allocs Instrs Reads Writes -------------------------------------------------------------------------------- circsim -0.1% 0.0% -0.0% -0.0% -0.0% constraints -0.0% 0.0% -0.0% -0.0% -0.0% fibheaps -0.0% 0.0% -0.0% -0.0% -0.0% gc_bench -0.0% 0.0% -0.0% -0.0% -0.0% hash -0.0% 0.0% -0.0% -0.0% -0.0% lcss -0.0% 0.0% -0.0% -0.0% -0.0% power -0.0% 0.0% -0.0% -0.0% -0.0% spellcheck -0.0% 0.0% -0.0% -0.0% -0.0% -------------------------------------------------------------------------------- Min -0.1% 0.0% -0.0% -0.0% -0.0% Max -0.0% 0.0% -0.0% -0.0% -0.0% Geometric Mean -0.0% +0.0% -0.0% -0.0% -0.0% Manual inspection of programs in testsuite/tests/programs --------------------------------------------------------- I built these programs with a bunch of dump flags and `-O` and compared STG, Cmm, and Asm dumps and file sizes. (Below the numbers in parenthesis show number of modules in the program) These programs have identical compiler (same .hi and .o sizes, STG, and Cmm and Asm dumps): - Queens (1), andre_monad (1), cholewo-eval (2), cvh_unboxing (3), andy_cherry (7), fun_insts (1), hs-boot (4), fast2haskell (2), jl_defaults (1), jq_readsPrec (1), jules_xref (1), jtod_circint (4), jules_xref2 (1), lennart_range (1), lex (1), life_space_leak (1), bargon-mangler-bug (7), record_upd (1), rittri (1), sanders_array (1), strict_anns (1), thurston-module-arith (2), okeefe_neural (1), joao-circular (6), 10queens (1) Programs with different compiler outputs: - jl_defaults (1): For some reason GHC HEAD marks a lot of top-level `[Int]` closures as CAFFY for no reason. With this patch we no longer make them CAFFY and generate less SRT entries. For some reason Main.o is slightly larger with this patch (1.3%) and the executable sizes are the same. (I'd expect both to be smaller) - launchbury (1): Same as jl_defaults: top-level `[Int]` closures marked as CAFFY for no reason. Similarly `Main.o` is 1.4% larger but the executable sizes are the same. - galois_raytrace (13): Differences are in the Parse module. There are a lot, but some of the changes are caused by the fact that for some reason (I think a bug) GHC HEAD marks the dictionary for `Functor Identity` as CAFFY. Parse.o is 0.4% larger, the executable size is the same. - north_array: We now generate less SRT entries because some of array primops used in this program like `NewArrayOp` get eliminated during Stg-to-Cmm and turn some CAFFY things into non-CAFFY. Main.o gets 24% larger (9224 bytes from 9000 bytes), executable sizes are the same. - seward-space-leak: Difference in this program is better shown by this smaller example: module Lib where data CDS = Case [CDS] [(Int, CDS)] | Call CDS CDS instance Eq CDS where Case sels1 rets1 == Case sels2 rets2 = sels1 == sels2 && rets1 == rets2 Call a1 b1 == Call a2 b2 = a1 == a2 && b1 == b2 _ == _ = False In this program GHC HEAD builds a new SRT for the recursive group of `(==)`, `(/=)` and the dictionary closure. Then `/=` points to `==` in its SRT field, and `==` uses the SRT object as its SRT. With this patch we use the closure for `/=` as the SRT and add `==` there. Then `/=` gets an empty SRT field and `==` points to `/=` in its SRT field. This change looks fine to me. Main.o gets 0.07% larger, executable sizes are identical. head.hackage ------------ head.hackage's CI script builds 428 packages from Hackage using this patch with no failures. Compiler performance -------------------- The compiler perf tests report that the compiler allocates slightly more (worst case observed so far is 4%). However most programs in the test suite are small, single file programs. To benchmark compiler performance on something more realistic I build Cabal (the library, 236 modules) with different optimisation levels. For the "max residency" row I run GHC with `+RTS -s -A100k -i0 -h` for more accurate numbers. Other rows are generated with just `-s`. (This is because `-i0` causes running GC much more frequently and as a result "bytes copied" gets inflated by more than 25x in some cases) * -O0 | | GHC HEAD | This MR | Diff | | --------------- | -------------- | -------------- | ------ | | Bytes allocated | 54,413,350,872 | 54,701,099,464 | +0.52% | | Bytes copied | 4,926,037,184 | 4,990,638,760 | +1.31% | | Max residency | 421,225,624 | 424,324,264 | +0.73% | * -O1 | | GHC HEAD | This MR | Diff | | --------------- | --------------- | --------------- | ------ | | Bytes allocated | 245,849,209,992 | 246,562,088,672 | +0.28% | | Bytes copied | 26,943,452,560 | 27,089,972,296 | +0.54% | | Max residency | 982,643,440 | 991,663,432 | +0.91% | * -O2 | | GHC HEAD | This MR | Diff | | --------------- | --------------- | --------------- | ------ | | Bytes allocated | 291,044,511,408 | 291,863,910,912 | +0.28% | | Bytes copied | 37,044,237,616 | 36,121,690,472 | -2.49% | | Max residency | 1,071,600,328 | 1,086,396,256 | +1.38% | Extra compiler allocations -------------------------- Runtime allocations of programs are as reported above (NoFib section). The compiler now allocates more than before. Main source of allocation in this patch compared to base commit is the new SRT algorithm (GHC.Cmm.Info.Build). Below is some of the extra work we do with this patch, numbers generated by profiled stage 2 compiler when building a pathological case (the test 'ManyConstructors') with '-O2': - We now sort the final STG for a module, which means traversing the entire program, generating free variable set for each top-level binding, doing SCC analysis, and re-ordering the program. In ManyConstructors this step allocates 97,889,952 bytes. - We now do SRT analysis on static data, which in a program like ManyConstructors causes analysing 10,000 bindings that we would previously just skip. This step allocates 70,898,352 bytes. - We now maintain an SRT map for the entire module as we compile Cmm groups: data ModuleSRTInfo = ModuleSRTInfo { ... , moduleSRTMap :: SRTMap } (SRTMap is just a strict Map from the 'containers' library) This map gets an entry for most bindings in a module (exceptions are THUNKs and CAFFY static functions). For ManyConstructors this map gets 50015 entries. - Once we're done with code generation we generate a NameSet from SRTMap for the non-CAFFY names in the current module. This set gets the same number of entries as the SRTMap. - Finally we update CafInfos in ModDetails for the non-CAFFY Ids, using the NameSet generated in the previous step. This usually does the least amount of allocation among the work listed here. Only place with this patch where we do less work in the CAF analysis in the tidying pass (CoreTidy). However that doesn't save us much, as the pass still needs to traverse the whole program and update IdInfos for other reasons. Only thing we don't here do is the `hasCafRefs` pass over the RHS of bindings, which is a stateless pass that returns a boolean value, so it doesn't allocate much. (Metric changes blow are all increased allocations) Metric changes -------------- Metric Increase: ManyAlternatives ManyConstructors T13035 T14683 T1969 T9961
2020-01-31testsuite: Don't crash on encoding failure in printBen Gamari
If the user doesn't use a Unicode locale then the testsuite driver would previously throw framework failures due to encoding failures. We now rather use the `replace` error-handling strategy.
2020-01-31base: Use one-shot kqueue on macOSBen Gamari
The underlying reason requiring that one-shot usage be disabled (#13903) has been fixed. Closes #15768.
2020-01-31rename: Eliminate usage of mkVarOccUniqueBen Gamari
Replacing it with `newSysName`. Fixes #17061.
2020-01-31Refactor package related codeSylvain Henry
The package terminology is a bit of a mess. Cabal packages contain components. Instances of these components when built with some flags/options/dependencies are called units. Units are registered into package databases and their metadata are called PackageConfig. GHC only knows about package databases containing units. It is a sad mismatch not fixed by this patch (we would have to rename parameters such as `package-id <unit-id>` which would affect users). This patch however fixes the following internal names: - Renames PackageConfig into UnitInfo. - Rename systemPackageConfig into globalPackageDatabase[Path] - Rename PkgConfXX into PkgDbXX - Rename pkgIdMap into unitIdMap - Rename ModuleToPkgDbAll into ModuleNameProvidersMap - Rename lookupPackage into lookupUnit - Add comments on DynFlags package related fields It also introduces a new `PackageDatabase` datatype instead of explicitly passing the following tuple: `(FilePath,[PackageConfig])`. The `pkgDatabase` field in `DynFlags` now contains the unit info for each unit of each package database exactly as they have been read from disk. Previously the command-line flag `-distrust-all-packages` would modify these unit info. Now this flag only affects the "dynamic" consolidated package state found in `pkgState` field. It makes sense because `initPackages` could be called first with this `distrust-all-packages` flag set and then again (using ghc-api) without and it should work (package databases are not read again from disk when `initPackages` is called the second time). Bump haddock submodule
2020-01-31Call `interpretPackageEnv` from `setSessionDynFlags`Sylvain Henry
interpretPackageEnv modifies the flags by reading the dreaded package environments. It is much less surprising to call it from `setSessionDynFlags` instead of reading package environments as a side-effect of `initPackages`.
2020-01-27Add two warnings to HadrianTom Ellis
2020-01-27Add two warnings to stage 2 buildTom Ellis
2020-01-27Disable two warnings for files that trigger themTom Ellis
incomplete-uni-patterns and incomplete-record-updates will be in -Wall at a future date, so prepare for that by disabling those warnings on files that trigger them.
2020-01-27Make Block.h compile with c++ compilersMatthew Pickering
2020-01-27Use splitLHs{ForAll,Sigma}TyInvis throughout the codebaseRyan Scott
Richard points out in #17688 that we use `splitLHsForAllTy` and `splitLHsSigmaTy` in places that we ought to be using the corresponding `-Invis` variants instead, identifying two bugs that are caused by this oversight: * Certain TH-quoted type signatures, such as those that appear in quoted `SPECIALISE` pragmas, silently turn visible `forall`s into invisible `forall`s. * When quoted, the type `forall a -> (a ~ a) => a` will turn into `forall a -> a` due to a bug in `DsMeta.repForall` that drops contexts that follow visible `forall`s. These are both ultimately caused by the fact that `splitLHsForAllTy` and `splitLHsSigmaTy` split apart visible `forall`s in addition to invisible ones. This patch cleans things up: * We now use `splitLHsForAllTyInvis` and `splitLHsSigmaTyInvis` throughout the codebase. Relatedly, the `splitLHsForAllTy` and `splitLHsSigmaTy` have been removed, as they are easy to misuse. * `DsMeta.repForall` now only handles invisible `forall`s to reduce the chance for confusion with visible `forall`s, which need to be handled differently. I also renamed it from `repForall` to `repForallT` to emphasize that its distinguishing characteristic is the fact that it desugars down to `L.H.TH.Syntax.ForallT`. Fixes #17688.
2020-01-25Do not bring visible foralls into scope in hsScopedTvswip/T17687Ryan Scott
Previously, `hsScopedTvs` (and its cousin `hsWcScopedTvs`) pretended that visible dependent quantification could not possibly happen at the term level, and cemented that assumption with an `ASSERT`: ```hs hsScopedTvs (HsForAllTy { hst_fvf = vis_flag, ... }) = ASSERT( vis_flag == ForallInvis ) ... ``` It turns out that this assumption is wrong. You can end up tripping this `ASSERT` if you stick it to the man and write a type for a term that uses visible dependent quantification anyway, like in this example: ```hs {-# LANGUAGE ScopedTypeVariables #-} x :: forall a -> a -> a x = x ``` That won't typecheck, but that's not the point. Before the typechecker has a chance to reject this, the renamer will try to use `hsScopedTvs` to bring `a` into scope over the body of `x`, since `a` is quantified by a `forall`. This, in turn, causes the `ASSERT` to fail. Bummer. Instead of walking on this dangerous ground, this patch makes GHC adopt a more hardline stance by pattern-matching directly on `ForallInvis` in `hsScopedTvs`: ```hs hsScopedTvs (HsForAllTy { hst_fvf = ForallInvis, ... }) = ... ``` Now `a` will not be brought over the body of `x` at all (which is how it should be), there's no chance of the `ASSERT` failing anymore (as it's gone), and best of all, the behavior of `hsScopedTvs` does not change. Everyone wins! Fixes #17687.
2020-01-25hadrian: Throw error on duplicate-named flavoursBen Gamari
Throw an error if the user requests a flavour for which there is more than one match. Fixes #17156.
2020-01-25Split glasgow_exts into several files (#17316)Sylvain Henry
2020-01-25Create ghci.cabal.shXavier Denis
2020-01-25Add ghc-in-ghci for stack based buildsXavier Denis
2020-01-25Fix rts allocateExec() on NetBSDPHO
Similar to SELinux, NetBSD "PaX mprotect" prohibits marking a page mapping both writable and executable at the same time. Use libffi which knows how to work around it.
2020-01-25Module hierarchy: Cmm (cf #13009)Sylvain Henry
2020-01-25Handle local fixity declarations in DsMeta properlyRyan Scott
`DsMeta.rep_sig` used to skip over `FixSig` entirely, which had the effect of causing local fixity declarations to be dropped when quoted in Template Haskell. But there is no good reason for this state of affairs, as the code in `DsMeta.repFixD` (which handles top-level fixity declarations) handles local fixity declarations just fine. This patch factors out the necessary parts of `repFixD` so that they can be used in `rep_sig` as well. There was one minor complication: the fixity signatures for class methods in each `HsGroup` were stored both in `FixSig`s _and_ the list of `LFixitySig`s for top-level fixity signatures, so I needed to take action to prevent fixity signatures for class methods being converted to `Dec`s twice. I tweaked `RnSource.add` to avoid putting these fixity signatures in two places and added `Note [Top-level fixity signatures in an HsGroup]` in `GHC.Hs.Decls` to explain the new design. Fixes #17608. Bumps the Haddock submodule.
2020-01-25PmCheck: Properly handle constructor-bound type variablesSebastian Graf
In https://gitlab.haskell.org/ghc/ghc/merge_requests/2192#note_246551 Simon convinced me that ignoring type variables existentially bound by data constructors have to be the same way as value binders. Sadly I couldn't think of a regression test, but I'm confident that this change strictly improves on the status quo.
2020-01-25PmCheck: Formulate as translation between Clause TreesSebastian Graf
We used to check `GrdVec`s arising from multiple clauses and guards in isolation. That resulted in a split between `pmCheck` and `pmCheckGuards`, the implementations of which were similar, but subtly different in detail. Also the throttling mechanism described in `Note [Countering exponential blowup]` ultimately got quite complicated because it had to cater for both checking functions. This patch realises that pattern match checking doesn't just consider single guarded RHSs, but that it's always a whole set of clauses, each of which can have multiple guarded RHSs in turn. We do so by translating a list of `Match`es to a `GrdTree`: ```haskell data GrdTree = Rhs !RhsInfo | Guard !PmGrd !GrdTree -- captures lef-to-right match semantics | Sequence !GrdTree !GrdTree -- captures top-to-bottom match semantics | Empty -- For -XEmptyCase, neutral element of Sequence ``` Then we have a function `checkGrdTree` that matches a given `GrdTree` against an incoming set of values, represented by `Deltas`: ```haskell checkGrdTree :: GrdTree -> Deltas -> CheckResult ... ``` Throttling is isolated to the `Sequence` case and becomes as easy as one would expect: When the union of uncovered values becomes too big, just return the original incoming `Deltas` instead (which is always a superset of the union, thus a sound approximation). The returned `CheckResult` contains two things: 1. The set of values that were not covered by any of the clauses, for exhaustivity warnings. 2. The `AnnotatedTree` that enriches the syntactic structure of the input program with divergence and inaccessibility information. This is `AnnotatedTree`: ```haskell data AnnotatedTree = AccessibleRhs !RhsInfo | InaccessibleRhs !RhsInfo | MayDiverge !AnnotatedTree | SequenceAnn !AnnotatedTree !AnnotatedTree | EmptyAnn ``` Crucially, `MayDiverge` asserts that the tree may force diverging values, so not all of its wrapped clauses can be redundant. While the set of uncovered values can be used to generate the missing equations for warning messages, redundant and proper inaccessible equations can be extracted from `AnnotatedTree` by `redundantAndInaccessibleRhss`. For this to work properly, the interface to the Oracle had to change. There's only `addPmCts` now, which takes a bag of `PmCt`s. There's a whole bunch of `PmCt` variants to replace the different oracle functions from before. The new `AnnotatedTree` structure allows for more accurate warning reporting (as evidenced by a number of changes spread throughout GHC's code base), thus we fix #17465. Fixes #17646 on the go. Metric Decrease: T11822 T9233 PmSeriesS haddock.compiler
2020-01-25Fix chaining tagged and untagged ptrs in compacting GCÖmer Sinan Ağacan
Currently compacting GC has the invariant that in a chain all fields are tagged the same. However this does not really hold: root pointers are not tagged, so when we thread a root we initialize a chain without a tag. When the pointed objects is evaluated and we have more pointers to it from the heap, we then add *tagged* fields to the chain (because pointers to it from the heap are tagged), ending up chaining fields with different tags (pointers from roots are NOT tagged, pointers from heap are). This breaks the invariant and as a result compacting GC turns tagged pointers into non-tagged. This later causes problem in the generated code where we do reads assuming that the pointer is aligned, e.g. 0x7(%rax) -- assumes that pointer is tagged 1 which causes misaligned reads. This caused #17088. We fix this using the "pointer tagging for large families" patch (#14373, !1742): - With the pointer tagging patch the GC can know what the tagged pointer to a CONSTR should be (previously we'd need to know the family size -- large families are always tagged 1, small families are tagged depending on the constructor). - Since we now know what the tags should be we no longer need to store the pointer tag in the info table pointers when forming chains in the compacting GC. As a result we no longer need to tag pointers in chains with 1/2 depending on whether the field points to an info table pointer, or to another field: an info table pointer is always tagged 0, everything else in the chain is tagged 1. The lost tags in pointers can be retrieved by looking at the info table. Finally, instead of using tag 1 for fields and tag 0 for info table pointers, we use two different tags for fields: - 1 for fields that have untagged pointers - 2 for fields that have tagged pointers When unchaining we then look at the pointer to a field, and depending on its tag we either leave a tagged pointer or an untagged pointer in the field. This allows chaining untagged and tagged fields together in compacting GC. Fixes #17088 Nofib results ------------- Binaries are smaller because of smaller `Compact.c` code. make mode=fast EXTRA_RUNTEST_OPTS="-cachegrind" EXTRA_HC_OPTS="-with-rtsopts=-c" NoFibRuns=1 -------------------------------------------------------------------------------- Program Size Allocs Instrs Reads Writes -------------------------------------------------------------------------------- CS -0.3% 0.0% +0.0% +0.0% +0.0% CSD -0.3% 0.0% +0.0% +0.0% +0.0% FS -0.3% 0.0% +0.0% -0.0% -0.0% S -0.3% 0.0% +5.4% +0.8% +3.9% VS -0.3% 0.0% +0.0% -0.0% -0.0% VSD -0.3% 0.0% -0.0% -0.0% -0.2% VSM -0.3% 0.0% +0.0% +0.0% +0.0% anna -0.1% 0.0% +0.0% +0.0% +0.0% ansi -0.3% 0.0% +0.1% +0.0% +0.0% atom -0.2% 0.0% +0.0% +0.0% +0.0% awards -0.2% 0.0% +0.0% 0.0% -0.0% banner -0.3% 0.0% +0.0% +0.0% +0.0% bernouilli -0.3% 0.0% +0.1% +0.0% +0.0% binary-trees -0.2% 0.0% +0.0% 0.0% +0.0% boyer -0.3% 0.0% +0.2% +0.0% +0.0% boyer2 -0.2% 0.0% +0.2% +0.1% +0.0% bspt -0.2% 0.0% +0.0% +0.0% +0.0% cacheprof -0.2% 0.0% +0.0% +0.0% +0.0% calendar -0.3% 0.0% +0.0% +0.0% +0.0% cichelli -0.3% 0.0% +1.1% +0.2% +0.5% circsim -0.2% 0.0% +0.0% -0.0% -0.0% clausify -0.3% 0.0% +0.0% -0.0% -0.0% comp_lab_zift -0.2% 0.0% +0.0% +0.0% +0.0% compress -0.3% 0.0% +0.0% +0.0% +0.0% compress2 -0.3% 0.0% +0.0% -0.0% -0.0% constraints -0.3% 0.0% +0.2% +0.1% +0.1% cryptarithm1 -0.3% 0.0% +0.0% -0.0% 0.0% cryptarithm2 -0.3% 0.0% +0.0% +0.0% +0.0% cse -0.3% 0.0% +0.0% +0.0% +0.0% digits-of-e1 -0.3% 0.0% +0.0% +0.0% +0.0% digits-of-e2 -0.3% 0.0% +0.0% +0.0% -0.0% dom-lt -0.2% 0.0% +0.0% +0.0% +0.0% eliza -0.2% 0.0% +0.0% +0.0% +0.0% event -0.3% 0.0% +0.1% +0.0% -0.0% exact-reals -0.2% 0.0% +0.0% +0.0% +0.0% exp3_8 -0.3% 0.0% +0.0% +0.0% +0.0% expert -0.2% 0.0% +0.0% +0.0% +0.0% fannkuch-redux -0.3% 0.0% -0.0% -0.0% -0.0% fasta -0.3% 0.0% +0.0% +0.0% +0.0% fem -0.2% 0.0% +0.1% +0.0% +0.0% fft -0.2% 0.0% +0.0% -0.0% -0.0% fft2 -0.2% 0.0% +0.0% -0.0% +0.0% fibheaps -0.3% 0.0% +0.0% -0.0% -0.0% fish -0.3% 0.0% +0.0% +0.0% +0.0% fluid -0.2% 0.0% +0.4% +0.1% +0.1% fulsom -0.2% 0.0% +0.0% +0.0% +0.0% gamteb -0.2% 0.0% +0.1% +0.0% +0.0% gcd -0.3% 0.0% +0.0% +0.0% +0.0% gen_regexps -0.3% 0.0% +0.0% -0.0% -0.0% genfft -0.3% 0.0% +0.0% +0.0% +0.0% gg -0.2% 0.0% +0.7% +0.3% +0.2% grep -0.2% 0.0% +0.0% +0.0% +0.0% hidden -0.2% 0.0% +0.0% +0.0% +0.0% hpg -0.2% 0.0% +0.1% +0.0% +0.0% ida -0.3% 0.0% +0.0% +0.0% +0.0% infer -0.2% 0.0% +0.0% -0.0% -0.0% integer -0.3% 0.0% +0.0% +0.0% +0.0% integrate -0.2% 0.0% +0.0% +0.0% +0.0% k-nucleotide -0.2% 0.0% +0.0% +0.0% -0.0% kahan -0.3% 0.0% -0.0% -0.0% -0.0% knights -0.3% 0.0% +0.0% -0.0% -0.0% lambda -0.3% 0.0% +0.0% -0.0% -0.0% last-piece -0.3% 0.0% +0.0% +0.0% +0.0% lcss -0.3% 0.0% +0.0% +0.0% 0.0% life -0.3% 0.0% +0.0% -0.0% -0.0% lift -0.2% 0.0% +0.0% +0.0% +0.0% linear -0.2% 0.0% +0.0% +0.0% +0.0% listcompr -0.3% 0.0% +0.0% +0.0% +0.0% listcopy -0.3% 0.0% +0.0% +0.0% +0.0% maillist -0.3% 0.0% +0.0% -0.0% -0.0% mandel -0.2% 0.0% +0.0% +0.0% +0.0% mandel2 -0.3% 0.0% +0.0% +0.0% +0.0% mate -0.2% 0.0% +0.0% +0.0% +0.0% minimax -0.3% 0.0% +0.0% +0.0% +0.0% mkhprog -0.2% 0.0% +0.0% +0.0% +0.0% multiplier -0.3% 0.0% +0.0% -0.0% -0.0% n-body -0.2% 0.0% -0.0% -0.0% -0.0% nucleic2 -0.2% 0.0% +0.0% +0.0% +0.0% para -0.2% 0.0% +0.0% -0.0% -0.0% paraffins -0.3% 0.0% +0.0% -0.0% -0.0% parser -0.2% 0.0% +0.0% +0.0% +0.0% parstof -0.2% 0.0% +0.8% +0.2% +0.2% pic -0.2% 0.0% +0.1% -0.1% -0.1% pidigits -0.3% 0.0% +0.0% +0.0% +0.0% power -0.2% 0.0% +0.0% -0.0% -0.0% pretty -0.3% 0.0% -0.0% -0.0% -0.1% primes -0.3% 0.0% +0.0% +0.0% -0.0% primetest -0.2% 0.0% +0.0% -0.0% -0.0% prolog -0.3% 0.0% +0.0% -0.0% -0.0% puzzle -0.3% 0.0% +0.0% +0.0% +0.0% queens -0.3% 0.0% +0.0% +0.0% +0.0% reptile -0.2% 0.0% +0.2% +0.1% +0.0% reverse-complem -0.3% 0.0% +0.0% +0.0% +0.0% rewrite -0.3% 0.0% +0.0% -0.0% -0.0% rfib -0.2% 0.0% +0.0% +0.0% -0.0% rsa -0.2% 0.0% +0.0% +0.0% +0.0% scc -0.3% 0.0% -0.0% -0.0% -0.1% sched -0.3% 0.0% +0.0% +0.0% +0.0% scs -0.2% 0.0% +0.1% +0.0% +0.0% simple -0.2% 0.0% +3.4% +1.0% +1.8% solid -0.2% 0.0% +0.0% +0.0% +0.0% sorting -0.3% 0.0% +0.0% +0.0% +0.0% spectral-norm -0.2% 0.0% -0.0% -0.0% -0.0% sphere -0.2% 0.0% +0.0% +0.0% +0.0% symalg -0.2% 0.0% +0.0% +0.0% +0.0% tak -0.3% 0.0% +0.0% +0.0% -0.0% transform -0.2% 0.0% +0.2% +0.1% +0.1% treejoin -0.3% 0.0% +0.2% -0.0% -0.1% typecheck -0.3% 0.0% +0.0% +0.0% +0.0% veritas -0.1% 0.0% +0.0% +0.0% +0.0% wang -0.2% 0.0% +0.0% -0.0% -0.0% wave4main -0.3% 0.0% +0.0% -0.0% -0.0% wheel-sieve1 -0.3% 0.0% +0.0% -0.0% -0.0% wheel-sieve2 -0.3% 0.0% +0.0% -0.0% -0.0% x2n1 -0.3% 0.0% +0.0% +0.0% +0.0% -------------------------------------------------------------------------------- Min -0.3% 0.0% -0.0% -0.1% -0.2% Max -0.1% 0.0% +5.4% +1.0% +3.9% Geometric Mean -0.3% -0.0% +0.1% +0.0% +0.1% -------------------------------------------------------------------------------- Program Size Allocs Instrs Reads Writes -------------------------------------------------------------------------------- circsim -0.2% 0.0% +1.6% +0.4% +0.7% constraints -0.3% 0.0% +4.3% +1.5% +2.3% fibheaps -0.3% 0.0% +3.5% +1.2% +1.3% fulsom -0.2% 0.0% +3.6% +1.2% +1.8% gc_bench -0.3% 0.0% +4.1% +1.3% +2.3% hash -0.3% 0.0% +6.6% +2.2% +3.6% lcss -0.3% 0.0% +0.7% +0.2% +0.7% mutstore1 -0.3% 0.0% +4.8% +1.4% +2.8% mutstore2 -0.3% 0.0% +3.4% +1.0% +1.7% power -0.2% 0.0% +2.7% +0.6% +1.9% spellcheck -0.3% 0.0% +1.1% +0.4% +0.4% -------------------------------------------------------------------------------- Min -0.3% 0.0% +0.7% +0.2% +0.4% Max -0.2% 0.0% +6.6% +2.2% +3.6% Geometric Mean -0.3% +0.0% +3.3% +1.0% +1.8% Metric changes -------------- While it sounds ridiculous, this change causes increased allocations in the following tests. We concluded that this change can't cause a difference in allocations and decided to land this patch. Fluctuations in "bytes allocated" metric is tracked in #17686. Metric Increase: Naperian T10547 T12150 T12234 T12425 T13035 T5837 T6048
2020-01-25`-ddump-str-signatures` dumps Text, not STG [skip ci]Sebastian Graf
2020-01-25Document the fact, that openFileBlocking can consume an OS thread indefinitely.Gabor Greif
Also state that a deadlock can happen with the non-threaded runtime. [ci skip]
2020-01-24testsuite: Widen acceptance window of T1969Ben Gamari
I have seen >20% fluctuations in this number, leading to spurious failures.
2020-01-20Avoid ./configure failure on NetBSDPHO
2020-01-20unregisterised: Fix declaration for stg_NO_FINALIZERBen Gamari
Previously it had a redundant _entry suffix. We never noticed this previously presumably because we never generated references to it (however hard to believe this may be). However, it did start failing in !1304.
2020-01-20Add missing Note [Improvement from Ground Wanteds]Ben Gamari
Closes #17659.
2020-01-20Put the docs for :instances in alphabetical positionXavier Denis
2020-01-20gitlab-ci: Allow submodule cleaning to fail on WindowsBen Gamari
Currently CI is inexplicably failing with ``` $ git submodule foreach git clean -xdf fatal: not a git repository: libffi-tarballs/../.git/modules/libffi-tarballs ``` I have no idea how this working tree got into such a state but we do need to fail more gracefully when it happens. Consequently, we allow the cleaning step to fail.
2020-01-20gitlab-ci: Reenable submodule linterBen Gamari
2020-01-20Remove deprecated -smp flagÖmer Sinan Ağacan
It was deprecated in 2012 with 46258b40
2020-01-20testsuite: Preserve more information in framework failuresBen Gamari
Namely print the entire exception in hopes that this will help track down #17649.