1. 14 Feb, 2021 1 commit
    • Sylvain Henry's avatar
      Refactor Logger · 8e2f85f6
      Sylvain Henry authored
      Before this patch, the only way to override GHC's default logging
      behavior was to set `log_action`, `dump_action` and `trace_action`
      fields in DynFlags. This patch introduces a new Logger abstraction and
      stores it in HscEnv instead.
      
      This is part of #17957 (avoid storing state in DynFlags). DynFlags are
      duplicated and updated per-module (because of OPTIONS_GHC pragma), so
      we shouldn't store global state in them.
      
      This patch also fixes a race in parallel "--make" mode which updated
      the `generatedDumps` IORef concurrently.
      
      Bump haddock submodule
      
      The increase in MultilayerModules is tracked in #19293.
      
      Metric Increase:
          MultiLayerModules
      8e2f85f6
  2. 01 Nov, 2020 1 commit
  3. 29 Oct, 2020 1 commit
    • Sylvain Henry's avatar
      Split GHC.Driver.Types · 0e9f6def
      Sylvain Henry authored
      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
      0e9f6def
  4. 10 Oct, 2020 1 commit
  5. 18 Sep, 2020 1 commit
    • Sylvain Henry's avatar
      Introduce OutputableP · ca48076a
      Sylvain Henry authored
      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).
      ca48076a
  6. 04 Sep, 2020 2 commits
  7. 31 Jul, 2020 1 commit
    • Sylvain Henry's avatar
      Refactor CLabel pretty-printing · 56a7c193
      Sylvain Henry authored
      Pretty-printing CLabel relies on sdocWithDynFlags that we want to remove
      (#10143, #17957). It uses it to query the backend and the platform.
      
      This patch exposes Clabel ppr functions specialised for each backend so
      that backend code can directly use them.
      56a7c193
  8. 23 Jul, 2020 1 commit
  9. 19 Jun, 2020 1 commit
  10. 01 May, 2020 1 commit
    • Sylvain Henry's avatar
      Refactor PprDebug handling · f8386c7b
      Sylvain Henry authored
      If `-dppr-debug` is set, then PprUser and PprDump styles are silently
      replaced with PprDebug style. This was done in `mkUserStyle` and
      `mkDumpStyle` smart constructors. As a consequence they needed a
      DynFlags parameter.
      
      Now we keep the original PprUser and PprDump styles until they are used
      to create an `SDocContext`. I.e. the substitution is only performed in
      `initSDocContext`.
      f8386c7b
  11. 26 Apr, 2020 1 commit
  12. 29 Mar, 2020 1 commit
  13. 19 Mar, 2020 1 commit
  14. 22 Feb, 2020 1 commit
  15. 31 Jan, 2020 1 commit
    • Ömer Sinan Ağacan's avatar
      Do CafInfo/SRT analysis in Cmm · c846618a
      Ömer Sinan Ağacan authored
      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
      c846618a
  16. 25 Jan, 2020 1 commit
  17. 04 Jan, 2020 1 commit
  18. 18 Dec, 2019 1 commit
    • Sylvain Henry's avatar
      Add GHC-API logging hooks · 58655b9d
      Sylvain Henry authored
      * Add 'dumpAction' hook to DynFlags.
      
      It allows GHC API users to catch dumped intermediate codes and
      information. The format of the dump (Core, Stg, raw text, etc.) is now
      reported allowing easier automatic handling.
      
      * Add 'traceAction' hook to DynFlags.
      
      Some dumps go through the trace mechanism (for instance unfoldings that
      have been considered for inlining). This is problematic because:
      1) dumps aren't written into files even with -ddump-to-file on
      2) dumps are written on stdout even with GHC API
      3) in this specific case, dumping depends on unsafe globally stored
      DynFlags which is bad for GHC API users
      
      We introduce 'traceAction' hook which allows GHC API to catch those
      traces and to avoid using globally stored DynFlags.
      
      * Avoid dumping empty logs via dumpAction/traceAction (but still write
      empty files to keep the existing behavior)
      58655b9d
  19. 23 Oct, 2019 1 commit
    • Andreas Klebinger's avatar
      Make dynflag argument for withTiming pure. · 6beea836
      Andreas Klebinger authored
      19 times out of 20 we already have dynflags in scope.
      
      We could just always use `return dflags`. But this is in fact not free.
      When looking at some STG code I noticed that we always allocate a
      closure for this expression in the heap. Clearly a waste in these cases.
      
      For the other cases we can either just modify the callsite to
      get dynflags or use the _D variants of withTiming I added which
      will use getDynFlags under the hood.
      6beea836
  20. 20 Sep, 2019 1 commit
    • Alp Mestanogullari's avatar
      ErrUtils: split withTiming into withTiming and withTimingSilent · b3e5c731
      Alp Mestanogullari authored
      'withTiming' becomes a function that, when passed '-vN' (N >= 2) or
      '-ddump-timings', will print timing (and possibly allocations) related
      information. When additionally built with '-eventlog' and executed with
      '+RTS -l', 'withTiming' will also emit both 'traceMarker' and 'traceEvent'
      events to the eventlog.
      
      'withTimingSilent' on the other hand will never print any timing information,
      under any circumstance, and will only emit 'traceEvent' events to the eventlog.
      As pointed out in !1672, 'traceMarker' is better suited for things that we
      might want to visualize in tools like eventlog2html, while 'traceEvent'
      is better suited for internal events that occur a lot more often and that we
      don't necessarily want to visualize.
      
      This addresses #17138 by using 'withTimingSilent' for all the codegen bits
      that are expressed as a bunch of small computations over streams of codegen
      ASTs.
      b3e5c731
  21. 03 Aug, 2019 1 commit
  22. 26 Jul, 2019 1 commit
  23. 13 Jul, 2019 1 commit
    • Andreas Klebinger's avatar
      Add two CmmSwitch optimizations. · 348cc8eb
      Andreas Klebinger authored
      Move switch expressions into a local variable when generating switches.
      This avoids duplicating the expression if we translate the switch
      to a tree search. This fixes #16933.
      
      Further we now check if all branches of a switch have the same
      destination, replacing the switch with a direct branch if that
      is the case.
      
      Both of these patterns appear in the ENTER macro used by the RTS
      but are unlikely to occur in intermediate Cmm generated by GHC.
      
      Nofib result summary:
      
      --------------------------------------------------------------------------------
              Program           Size    Allocs   Runtime   Elapsed  TotalMem
      --------------------------------------------------------------------------------
                  Min          -0.0%     -0.0%    -15.7%    -15.6%      0.0%
                  Max          -0.0%      0.0%     +5.4%     +5.5%      0.0%
       Geometric Mean          -0.0%     -0.0%     -1.0%     -1.0%     -0.0%
      
      Compiler allocations go up slightly: +0.2%
      
      Example output before and after the change taken from RTS code below.
      
      All but one of the memory loads `I32[_c3::I64 - 8]` are eliminated.
      Instead the data is loaded once from memory in block c6.
      
      Also the switch in block `ud` in the original code has been
      eliminated completely.
      
      Cmm without this commit:
      
      ```
      stg_ap_0_fast() { //  [R1]
              { []
              }
          {offset
            ca: _c1::P64 = R1;   // CmmAssign
                goto c2;   // CmmBranch
            c2: if (_c1::P64 & 7 != 0) goto c4; else goto c6;
            c6: _c3::I64 = I64[_c1::P64];
                if (I32[_c3::I64 - 8] < 26 :: W32) goto ub; else goto ug;
            ub: if (I32[_c3::I64 - 8] < 15 :: W32) goto uc; else goto ue;
            uc: if (I32[_c3::I64 - 8] < 8 :: W32) goto c7; else goto ud;
            ud: switch [8 .. 14] (%MO_SS_Conv_W32_W64(I32[_c3::I64 - 8])) {
                    case 8, 9, 10, 11, 12, 13, 14 : goto c4;
                }
            ue: if (I32[_c3::I64 - 8] >= 25 :: W32) goto c4; else goto uf;
            uf: if (%MO_SS_Conv_W32_W64(I32[_c3::I64 - 8]) != 23) goto c7; else goto c4;
            c4: R1 = _c1::P64;
                call (P64[Sp])(R1) args: 8, res: 0, upd: 8;
            ug: if (I32[_c3::I64 - 8] < 28 :: W32) goto uh; else goto ui;
            uh: if (I32[_c3::I64 - 8] < 27 :: W32) goto c7; else goto c8;
            ui: if (I32[_c3::I64 - 8] < 29 :: W32) goto c8; else goto c7;
            c8: _c1::P64 = P64[_c1::P64 + 8];
                goto c2;
            c7: R1 = _c1::P64;
                call (_c3::I64)(R1) args: 8, res: 0, upd: 8;
          }
      }
      ```
      
      Cmm with this commit:
      
      ```
      stg_ap_0_fast() { //  [R1]
              { []
              }
          {offset
            ca: _c1::P64 = R1;
                goto c2;
            c2: if (_c1::P64 & 7 != 0) goto c4; else goto c6;
            c6: _c3::I64 = I64[_c1::P64];
                _ub::I64 = %MO_SS_Conv_W32_W64(I32[_c3::I64 - 8]);
                if (_ub::I64 < 26) goto uc; else goto uh;
            uc: if (_ub::I64 < 15) goto ud; else goto uf;
            ud: if (_ub::I64 < 8) goto c7; else goto c4;
            uf: if (_ub::I64 >= 25) goto c4; else goto ug;
            ug: if (_ub::I64 != 23) goto c7; else goto c4;
            c4: R1 = _c1::P64;
                call (P64[Sp])(R1) args: 8, res: 0, upd: 8;
            uh: if (_ub::I64 < 28) goto ui; else goto uj;
            ui: if (_ub::I64 < 27) goto c7; else goto c8;
            uj: if (_ub::I64 < 29) goto c8; else goto c7;
            c8: _c1::P64 = P64[_c1::P64 + 8];
                goto c2;
            c7: R1 = _c1::P64;
                call (_c3::I64)(R1) args: 8, res: 0, upd: 8;
          }
      }
      ```
      348cc8eb
  24. 20 Jun, 2019 1 commit
    • John Ericson's avatar
      Move 'Platform' to ghc-boot · bff2f24b
      John Ericson authored
      ghc-pkg needs to be aware of platforms so it can figure out which
      subdire within the user package db to use. This is admittedly
      roundabout, but maybe Cabal could use the same notion of a platform as
      GHC to good affect too.
      bff2f24b
  25. 01 Jan, 2019 1 commit
  26. 17 Nov, 2018 1 commit
    • Andreas Klebinger's avatar
      NCG: New code layout algorithm. · 912fd2b6
      Andreas Klebinger authored
      Summary:
      This patch implements a new code layout algorithm.
      It has been tested for x86 and is disabled on other platforms.
      
      Performance varies slightly be CPU/Machine but in general seems to be better
      by around 2%.
      Nofib shows only small differences of about +/- ~0.5% overall depending on
      flags/machine performance in other benchmarks improved significantly.
      
      Other benchmarks includes at least the benchmarks of: aeson, vector, megaparsec, attoparsec,
      containers, text and xeno.
      
      While the magnitude of gains differed three different CPUs where tested with
      all getting faster although to differing degrees. I tested: Sandy Bridge(Xeon), Haswell,
      Skylake
      
      * Library benchmark results summarized:
        * containers: ~1.5% faster
        * aeson: ~2% faster
        * megaparsec: ~2-5% faster
        * xml library benchmarks: 0.2%-1.1% faster
        * vector-benchmarks: 1-4% faster
        * text: 5.5% faster
      
      On average GHC compile times go down, as GHC compiled with the new layout
      is faster than the overhead introduced by using the new layout algorithm,
      
      Things this patch does:
      
      * Move code responsilbe for block layout in it's own module.
      * Move the NcgImpl Class into the NCGMonad module.
      * Extract a control flow graph from the input cmm.
      * Update this cfg to keep it in sync with changes during
        asm codegen. This has been tested on x64 but should work on x86.
        Other platforms still use the old codelayout.
      * Assign weights to the edges in the CFG based on type and limited static
        analysis which are then used for block layout.
      * Once we have the final code layout eliminate some redundant jumps.
      
        In particular turn a sequences of:
            jne .foo
            jmp .bar
          foo:
        into
            je bar
          foo:
            ..
      
      Test Plan: ci
      
      Reviewers: bgamari, jmct, jrtc27, simonmar, simonpj, RyanGlScott
      
      Reviewed By: RyanGlScott
      
      Subscribers: RyanGlScott, trommler, jmct, carter, thomie, rwbarton
      
      GHC Trac Issues: #15124
      
      Differential Revision: https://phabricator.haskell.org/D4726
      912fd2b6
  27. 16 May, 2018 1 commit
    • Simon Marlow's avatar
      An overhaul of the SRT representation · eb8e692c
      Simon Marlow authored
      Summary:
      - Previously we would hvae a single big table of pointers per module,
        with a set of bitmaps to reference entries within it. The new
        representation is identical to a static constructor, which is much
        simpler for the GC to traverse, and we get to remove the complicated
        bitmap-traversal code from the GC.
      
      - Rewrite all the code to generate SRTs in CmmBuildInfoTables, and
        document it much better (see Note [SRTs]). This has been something
        I've wanted to do since we moved to the new code generator, I
        finally had the opportunity to finish it while on a transatlantic
        flight recently :)
      
      There are a series of 4 diffs:
      
      1. D4632 (this one), which does the bulk of the changes
      
      2. D4633 which adds support for smaller `CmmLabelDiffOff` constants
      
      3. D4634 which takes advantage of D4632 and D4633 to save a word in
         info tables that have an SRT on x86_64. This is where most of the
         binary size improvement comes from.
      
      4. D4637 which makes a further optimisation to merge some SRTs with
         static FUN closures.  This adds some complexity and the benefits
         are fairly modest, so it's not clear yet whether we should do this.
      
      Results (after (3), on x86_64)
      
      - GHC itself (staticaly linked) is 5.2% smaller
      
      - -1.7% binary sizes in nofib, -2.9% module sizes. Full nofib results: P176
      
      - I measured the overhead of traversing all the static objects in a
        major GC in GHC itself by doing `replicateM_ 1000 performGC` as the
        first thing in `Main.main`.  The new version was 5-10% faster, but
        the results did vary quite a bit.
      
      - I'm not sure if there's a compile-time difference, the results are
        too unreliable.
      
      Test Plan: validate
      
      Reviewers: bgamari, michalt, niteria, simonpj, erikd, osa1
      
      Subscribers: thomie, carter
      
      Differential Revision: https://phabricator.haskell.org/D4632
      eb8e692c
  28. 13 Apr, 2018 1 commit
  29. 27 Mar, 2018 1 commit
    • Michal Terepeta's avatar
      CmmPipeline: add a second pass of CmmCommonBlockElim · d5c4d46a
      Michal Terepeta authored
      The sinking pass often gets rid of unnecessary registers
      registers/assignements exposing more opportunities for CBE, so this
      commit adds a second round of CBE after the sinking pass and should
      fix #12915 (and some examples in #14226).
      
      Nofib results:
      * Binary size:         0.9% reduction on average
      * Compile allocations: 0.7% increase on average
      * Runtime:             noisy, two separate runs of nofib showed a tiny
                             reduction on average, (~0.2-0.3%), but I think
                             this is mostly noise
      * Compile time:        very noisy, but generally within +/- 0.5% (one
                             run faster, one slower)
      
      One interesting part of this change is that running CBE invalidates
      results of proc-point analysis. But instead of re-doing the whole
      analysis, we can use the map that CBE creates for replacing/comparing
      block labels (maps a redundant label to a useful one) to update the
      results of proc-point analysis. This lowers the overhead compared to the
      previous experiment in #12915.
      Signed-off-by: Michal Terepeta's avatarMichal Terepeta <michal.terepeta@gmail.com>
      
      Test Plan: ./validate
      
      Reviewers: bgamari, simonmar
      
      Reviewed By: simonmar
      
      Subscribers: rwbarton, thomie, carter
      
      GHC Trac Issues: #12915, #14226
      
      Differential Revision: https://phabricator.haskell.org/D4417
      d5c4d46a
  30. 04 Feb, 2018 1 commit
    • Ben Gamari's avatar
      cmm: Revert more aggressive CBE due to #14226 · 50adbd7c
      Ben Gamari authored
      Trac #14226 noted that the C-- CBE pass frequently fails to
      common up semantically identical blocks due to the differences in local
      register naming. These patches fixed this by making the pass consider
      equality up to alpha-renaming.
      
      However, the new logic failed to consider the possibility that local
      register naming *may* matter across multiple blocks. This lead to the
      regression #14754. I'll need to do a bit of thinking on a proper
      solution to this but in the meantime I'm reverting all four patches.
      
      This reverts commit a27056f9.
      This reverts commit 6f990c54.
      This reverts commit 9aa73892.
      This reverts commit 7920a7d9.
      50adbd7c
  31. 21 Sep, 2017 1 commit
    • Ben Gamari's avatar
      cmm/CBE: Use foldLocalRegsDefd · 9aa73892
      Ben Gamari authored
      Simonpj suggested this as a follow-on to #14226 to avoid code
      duplication. This also gives us the ability to CBE cases involving
      foreign calls for free.
      
      Test Plan: Validate
      
      Reviewers: austin, simonmar, simonpj
      
      Reviewed By: simonpj
      
      Subscribers: michalt, simonpj, rwbarton, thomie
      
      GHC Trac Issues: #14226
      
      Differential Revision: https://phabricator.haskell.org/D3999
      9aa73892
  32. 19 Sep, 2017 1 commit
    • Herbert Valerio Riedel's avatar
      compiler: introduce custom "GhcPrelude" Prelude · f63bc730
      Herbert Valerio Riedel authored
      This switches the compiler/ component to get compiled with
      -XNoImplicitPrelude and a `import GhcPrelude` is inserted in all
      modules.
      
      This is motivated by the upcoming "Prelude" re-export of
      `Semigroup((<>))` which would cause lots of name clashes in every
      modulewhich imports also `Outputable`
      
      Reviewers: austin, goldfire, bgamari, alanz, simonmar
      
      Reviewed By: bgamari
      
      Subscribers: goldfire, rwbarton, thomie, mpickering, bgamari
      
      Differential Revision: https://phabricator.haskell.org/D3989
      f63bc730
  33. 22 Aug, 2017 1 commit
  34. 23 Jun, 2017 1 commit
    • Michal Terepeta's avatar
      Hoopl: remove dependency on Hoopl package · 42eee6ea
      Michal Terepeta authored
      This copies the subset of Hoopl's functionality needed by GHC to
      `cmm/Hoopl` and removes the dependency on the Hoopl package.
      
      The main motivation for this change is the confusing/noisy interface
      between GHC and Hoopl:
      - Hoopl has `Label` which is GHC's `BlockId` but different than
        GHC's `CLabel`
      - Hoopl has `Unique` which is different than GHC's `Unique`
      - Hoopl has `Unique{Map,Set}` which are different than GHC's
        `Uniq{FM,Set}`
      - GHC has its own specialized copy of `Dataflow`, so `cmm/Hoopl` is
        needed just to filter the exposed functions (filter out some of the
        Hoopl's and add the GHC ones)
      With this change, we'll be able to simplify this significantly.
      It'll also be much easier to do invasive changes (Hoopl is a public
      package on Hackage with users that depend on the current behavior)
      
      This should introduce no changes in functionality - it merely
      copies the relevant code.
      Signed-off-by: Michal Terepeta's avatarMichal Terepeta <michal.terepeta@gmail.com>
      
      Test Plan: ./validate
      
      Reviewers: austin, bgamari, simonmar
      
      Reviewed By: bgamari, simonmar
      
      Subscribers: simonpj, kavon, rwbarton, thomie
      
      Differential Revision: https://phabricator.haskell.org/D3616
      42eee6ea
  35. 15 Dec, 2016 1 commit
  36. 16 Jul, 2016 1 commit
    • tvv's avatar
      CodeGen: Way to dump cmm only once (#11717) · 1ba79fa4
      tvv authored
      The `-ddump-cmm` put all stages of Cmm processing into one output.
      This patch changes its behavior and adds two more options to make
      Cmm dumping flexible.
      
      - `-ddump-cmm-from-stg` dumps only initial version of  Cmm right after
         STG->Cmm codegen
      - `-ddump-cmm` dumps the final result of the Cmm pipeline processing
      - `-ddump-cmm-verbose` dumps intermediate output of each Cmm pipeline
         step
      - `-ddump-cmm-proc` and `-ddump-cmm-caf` seems were lost. Now enabled
      
      Test Plan: ./validate
      
      Reviewers: thomie, simonmar, austin, bgamari
      
      Reviewed By: thomie, simonmar
      
      Subscribers: simonpj, thomie
      
      Differential Revision: https://phabricator.haskell.org/D2393
      
      GHC Trac Issues: #11717
      1ba79fa4
  37. 30 Mar, 2015 1 commit
    • Joachim Breitner's avatar
      Refactor the story around switches (#10137) · de1160be
      Joachim Breitner authored
      This re-implements the code generation for case expressions at the Stg →
      Cmm level, both for data type cases as well as for integral literal
      cases. (Cases on float are still treated as before).
      
      The goal is to allow for fancier strategies in implementing them, for a
      cleaner separation of the strategy from the gritty details of Cmm, and
      to run this later than the Common Block Optimization, allowing for one
      way to attack #10124. The new module CmmSwitch contains a number of
      notes explaining this changes. For example, it creates larger
      consecutive jump tables than the previous code, if possible.
      
      nofib shows little significant overall improvement of runtime. The
      rather large wobbling comes from changes in the code block order
      (see #8082, not much we can do about it). But the decrease in code size
      alone makes this worthwhile.
      
      ```
              Program           Size    Allocs   Runtime   Elapsed  TotalMem
                  Min          -1.8%      0.0%     -6.1%     -6.1%     -2.9%
                  Max          -0.7%     +0.0%     +5.6%     +5.7%     +7.8%
       Geometric Mean          -1.4%     -0.0%     -0.3%     -0.3%     +0.0%
      ```
      
      Compilation time increases slightly:
      ```
              -1 s.d.                -----            -2.0%
              +1 s.d.                -----            +2.5%
              Average                -----            +0.3%
      ```
      
      The test case T783 regresses a lot, but it is the only one exhibiting
      any regression. The cause is the changed order of branches in an
      if-then-else tree, which makes the hoople data flow analysis traverse
      the blocks in a suboptimal order. Reverting that gets rid of this
      regression, but has a consistent, if only very small (+0.2%), negative
      effect on runtime. So I conclude that this test is an extreme outlier
      and no reason to change the code.
      
      Differential Revision: https://phabricator.haskell.org/D720
      de1160be
  38. 01 Aug, 2014 1 commit
  39. 08 Jun, 2014 1 commit