1. 01 Oct, 2020 1 commit
  2. 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
  3. 21 Aug, 2020 2 commits
  4. 19 Aug, 2020 1 commit
    • Sylvain Henry's avatar
      DynFlags: refactor GHC.CmmToAsm (#17957, #10143) · 0c5ed5c7
      Sylvain Henry authored
      This patch removes the use of `sdocWithDynFlags` from GHC.CmmToAsm.*.Ppr
      
      To do that I've had to make some refactoring:
      
      * X86' and PPC's `Instr` are no longer `Outputable` as they require a
        `Platform` argument
      
      * `Instruction` class now exposes `pprInstr :: Platform -> instr -> SDoc`
      
      * as a consequence, I've refactored some modules to avoid .hs-boot files
      
      * added (derived) functor instances for some datatypes parametric in the
        instruction type. It's useful for pretty-printing as we just have to
        map `pprInstr` before pretty-printing the container datatype.
      0c5ed5c7
  5. 12 Aug, 2020 1 commit
    • Sylvain Henry's avatar
      DynFlags: disentangle Outputable · accbc242
      Sylvain Henry authored
      - put panic related functions into GHC.Utils.Panic
      - put trace related functions using DynFlags in GHC.Driver.Ppr
      
      One step closer making Outputable fully independent of DynFlags.
      
      Bump haddock submodule
      accbc242
  6. 07 Aug, 2020 1 commit
    • Ben Gamari's avatar
      nativeGen: One approach to fix #18527 · 15b36de0
      Ben Gamari authored
      Previously the code generator could produce corrupt C call sequences due
      to register overlap between MachOp lowerings and the platform's calling
      convention. We fix this using a hack described in Note [Evaluate C-call
      arguments before placing in destination registers].
      15b36de0
  7. 02 Jul, 2020 1 commit
    • Sylvain Henry's avatar
      NCG: correctly handle addresses with huge offsets (#15570) · 3cdd8d69
      Sylvain Henry authored
      Before this patch we could generate addresses of this form:
      
         movzbl cP0_str+-9223372036854775808,%eax
      
      The linker can't handle them because the offset is too large:
      
         ld.lld: error: Main.o:(.text+0xB3): relocation R_X86_64_32S out of range: -9223372036852653050 is not in [-2147483648, 2147483647]
      
      With this patch we detect those cases and generate:
      
         movq $-9223372036854775808,%rax
         addq $cP0_str,%rax
         movzbl (%rax),%eax
      
      I've also refactored `getAmode` a little bit to make it easier to
      understand and to trace.
      3cdd8d69
  8. 14 Jun, 2020 1 commit
  9. 10 Jun, 2020 1 commit
  10. 30 Apr, 2020 1 commit
  11. 26 Apr, 2020 1 commit
  12. 21 Apr, 2020 1 commit
    • Sylvain Henry's avatar
      CmmToAsm DynFlags refactoring (#17957) · 747093b7
      Sylvain Henry authored
      * Remove `DynFlags` parameter from `isDynLinkName`: `isDynLinkName` used
        to test the global `ExternalDynamicRefs` flag. Now we test it outside of
        `isDynLinkName`
      
      * Add new fields into `NCGConfig`: current unit id, sse/bmi versions,
        externalDynamicRefs, etc.
      
      * Replace many uses of `DynFlags` by `NCGConfig`
      
      * Moved `BMI/SSE` datatypes into `GHC.Platform`
      747093b7
  13. 03 Apr, 2020 1 commit
    • Sylvain Henry's avatar
      Refactor CmmStatics · cc2918a0
      Sylvain Henry authored
      In !2959 we noticed that there was some redundant code (in GHC.Cmm.Utils
      and GHC.Cmm.StgToCmm.Utils) used to deal with `CmmStatics` datatype
      (before SRT generation) and `RawCmmStatics` datatype (after SRT
      generation).
      
      This patch removes this redundant code by using a single GADT for
      (Raw)CmmStatics.
      cc2918a0
  14. 29 Mar, 2020 1 commit
  15. 26 Mar, 2020 1 commit
    • Sylvain Henry's avatar
      DynFlags refactoring III · 0de03cd7
      Sylvain Henry authored
      Use Platform instead of DynFlags when possible:
      * `tARGET_MIN_INT` et al. replaced with `platformMinInt` et al.
      * no more DynFlags in PreRules: added a new `RuleOpts` datatype
      * don't use `wORD_SIZE` in the compiler
      * make `wordAlignment` use `Platform`
      * make `dOUBLE_SIZE` a constant
      
      Metric Decrease:
          T13035
          T1969
      0de03cd7
  16. 19 Mar, 2020 1 commit
  17. 15 Mar, 2020 1 commit
    • Sylvain Henry's avatar
      Refactor CmmToAsm (disentangle DynFlags) · 2e82465f
      Sylvain Henry authored
      This patch disentangles a bit more DynFlags from the native code
      generator (CmmToAsm).
      
      In more details:
      
      - add a new NCGConfig datatype in GHC.CmmToAsm.Config which contains the
        configuration of a native code generation session
      - explicitly pass NCGConfig/Platform arguments when necessary
      - as a consequence `sdocWithPlatform` is gone and there are only a few
        `sdocWithDynFlags` left
      - remove the use of `unsafeGlobalDynFlags` from GHC.CmmToAsm.CFG
      - remove `sdocDebugLevel` (now we pass the debug level via NCGConfig)
      
      There are still some places where DynFlags is used, especially because
      of pretty-printing (CLabel), because of Cmm helpers (such as
      `cmmExprType`) and because of `Outputable` instance for the
      instructions. These are left for future refactoring as this patch is
      already big.
      2e82465f
  18. 26 Feb, 2020 1 commit
  19. 25 Feb, 2020 1 commit
  20. 22 Feb, 2020 1 commit
  21. 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
  22. 27 Jan, 2020 1 commit
  23. 25 Jan, 2020 1 commit
  24. 13 Jan, 2020 1 commit
  25. 03 Dec, 2019 1 commit
  26. 23 Oct, 2019 1 commit
    • Andreas Klebinger's avatar
      Fix bug in the x86 backend involving the CFG. · aa778152
      Andreas Klebinger authored
      This is part two of fixing #17334.
      
      There are two parts to this commit:
      
      - A bugfix for computing loop levels
      - A bugfix of basic block invariants in the NCG.
      
      -----------------------------------------------------------
      
      In the first bug we ended up with a CFG of the sort: [A -> B -> C]
      This was represented via maps as fromList [(A,B),(B,C)] and later
      transformed into a adjacency array. However the transformation did
      not include block C in the array (since we only looked at the keys of
      the map).
      
      This was still fine until we tried to look up successors for C and tried
      to read outside of the array bounds when accessing C.
      
      In order to prevent this in the future I refactored to code to include
      all nodes as keys in the map representation. And make this a invariant
      which is checked in a few places.
      
      Overall I expect this to make the code more robust as now any failed
      lookup will represent an error, versus failed lookups sometimes being
      expected and sometimes not.
      
      In terms of performance this makes some things cheaper (getting a list
      of all nodes) and others more expensive (adding a new edge). Overall
      this adds up to no noteable performance difference.
      
      -----------------------------------------------------------
      
      Part 2: When the NCG generated a new basic block, it did
      not always insert a NEWBLOCK meta instruction in the stream which
      caused a quite subtle bug.
      
          During instruction selection a statement `s`
          in a block B with control of the sort: B -> C
          will sometimes result in control
          flow of the sort:
      
                  ┌ < ┐
                  v   ^
            B ->  B1  ┴ -> C
      
          as is the case for some atomic operations.
      
          Now to keep the CFG in sync when introducing B1 we clearly
          want to insert it between B and C. However there is
          a catch when we have to deal with self loops.
      
          We might start with code and a CFG of these forms:
      
          loop:
              stmt1               ┌ < ┐
              ....                v   ^
              stmtX              loop ┘
              stmtY
              ....
              goto loop:
      
          Now we introduce B1:
                                  ┌ ─ ─ ─ ─ ─┐
              loop:               │   ┌ <  ┐ │
              instrs              v   │    │ ^
              ....               loop ┴ B1 ┴ ┘
              instrsFromX
              stmtY
              goto loop:
      
          This is simple, all outgoing edges from loop now simply
          start from B1 instead and the code generator knows which
          new edges it introduced for the self loop of B1.
      
          Disaster strikes if the statement Y follows the same pattern.
          If we apply the same rule that all outgoing edges change then
          we end up with:
      
              loop ─> B1 ─> B2 ┬─┐
                │      │    └─<┤ │
                │      └───<───┘ │
                └───────<────────┘
      
          This is problematic. The edge B1->B1 is modified as expected.
          However the modification is wrong!
      
          The assembly in this case looked like this:
      
          _loop:
              <instrs>
          _B1:
              ...
              cmpxchgq ...
              jne _B1
              <instrs>
              <end _B1>
          _B2:
              ...
              cmpxchgq ...
              jne _B2
              <instrs>
              jmp loop
      
          There is no edge _B2 -> _B1 here. It's still a self loop onto _B1.
      
          The problem here is that really B1 should be two basic blocks.
          Otherwise we have control flow in the *middle* of a basic block.
          A contradiction!
      
          So to account for this we add yet another basic block marker:
      
          _B:
              <instrs>
          _B1:
              ...
              cmpxchgq ...
              jne _B1
              jmp _B1'
          _B1':
              <instrs>
              <end _B1>
          _B2:
              ...
      
          Now when inserting B2 we will only look at the outgoing edges of B1' and
          everything will work out nicely.
      
          You might also wonder why we don't insert jumps at the end of _B1'. There is
          no way another block ends up jumping to the labels _B1 or _B2 since they are
          essentially invisible to other blocks. View them as control flow labels local
          to the basic block if you'd like.
      
          Not doing this ultimately caused (part 2 of) #17334.
      aa778152
  27. 16 Oct, 2019 1 commit
    • Andreas Klebinger's avatar
      Add loop level analysis to the NCG backend. · 535a88e1
      Andreas Klebinger authored
      For backends maintaining the CFG during codegen
      we can now find loops and their nesting level.
      
      This is based on the Cmm CFG and dominator analysis.
      
      As a result we can estimate edge frequencies a lot better
      for methods, resulting in far better code layout.
      
      Speedup on nofib: ~1.5%
      Increase in compile times: ~1.9%
      
      To make this feasible this commit adds:
      * Dominator analysis based on the Lengauer-Tarjan Algorithm.
      * An algorithm estimating global edge frequences from branch
      probabilities - In CFG.hs
      
      A few static branch prediction heuristics:
      
      * Expect to take the backedge in loops.
      * Expect to take the branch NOT exiting a loop.
      * Expect integer vs constant comparisons to be false.
      
      We also treat heap/stack checks special for branch prediction
      to avoid them being treated as loops.
      535a88e1
  28. 13 Oct, 2019 1 commit
    • Andreas Klebinger's avatar
      Fix #17334 where NCG did not properly update the CFG. · c1bd07cd
      Andreas Klebinger authored
      Statements can change the basic block in which instructions
      are placed during instruction selection.
      
      We have to keep track of this switch of the current basic block
      as we need this information in order to properly update the CFG.
      
      This commit implements this change and fixes #17334.
      
      We do so by having stmtToInstr return the new block id
      if a statement changed the basic block.
      c1bd07cd
  29. 05 Oct, 2019 1 commit
    • John Ericson's avatar
      Clean up `#include`s in the compiler · ee8118ca
      John Ericson authored
       - Remove unneeded ones
      
       - Use <..> for inter-package.
         Besides general clean up, helps distinguish between the RTS we link
         against vs the RTS we compile for.
      ee8118ca
  30. 25 Sep, 2019 1 commit
    • Sebastian Graf's avatar
      PmCheck: Only ever check constantly many models against a single pattern · ebc65025
      Sebastian Graf authored
      Introduces a new flag `-fmax-pmcheck-deltas` to achieve that. Deprecates
      the old `-fmax-pmcheck-iter` mechanism in favor of this new flag.
      
      From the user's guide:
      
      Pattern match checking can be exponential in some cases. This limit makes sure
      we scale polynomially in the number of patterns, by forgetting refined
      information gained from a partially successful match. For example, when
      matching `x` against `Just 4`, we split each incoming matching model into two
      sub-models: One where `x` is not `Nothing` and one where `x` is `Just y` but
      `y` is not `4`. When the number of incoming models exceeds the limit, we
      continue checking the next clause with the original, unrefined model.
      
      This also retires the incredibly hard to understand "maximum number of
      refinements" mechanism, because the current mechanism is more general
      and should catch the same exponential cases like PrelRules at the same
      time.
      
      -------------------------
      Metric Decrease:
          T11822
      -------------------------
      ebc65025
  31. 13 Sep, 2019 1 commit
  32. 09 Sep, 2019 1 commit
    • Sylvain Henry's avatar
      Module hierarchy: StgToCmm (#13009) · 447864a9
      Sylvain Henry authored
      Add StgToCmm module hierarchy. Platform modules that are used in several
      other places (NCG, LLVM codegen, Cmm transformations) are put into
      GHC.Platform.
      447864a9
  33. 15 Aug, 2019 1 commit
    • James Foster's avatar
      Remove unused imports of the form 'import foo ()' (Fixes #17065) · ca71d551
      James Foster authored
      These kinds of imports are necessary in some cases such as
      importing instances of typeclasses or intentionally creating
      dependencies in the build system, but '-Wunused-imports' can't
      detect when they are no longer needed. This commit removes the
      unused ones currently in the code base (not including test files
      or submodules), with the hope that doing so may increase
      parallelism in the build system by removing unnecessary
      dependencies.
      ca71d551
  34. 16 Jul, 2019 1 commit
  35. 03 Jul, 2019 1 commit
  36. 28 Jun, 2019 1 commit
    • Travis Whitaker's avatar
      Correct closure observation, construction, and mutation on weak memory machines. · 11bac115
      Travis Whitaker authored
      Here the following changes are introduced:
          - A read barrier machine op is added to Cmm.
          - The order in which a closure's fields are read and written is changed.
          - Memory barriers are added to RTS code to ensure correctness on
            out-or-order machines with weak memory ordering.
      
      Cmm has a new CallishMachOp called MO_ReadBarrier. On weak memory machines, this
      is lowered to an instruction that ensures memory reads that occur after said
      instruction in program order are not performed before reads coming before said
      instruction in program order. On machines with strong memory ordering properties
      (e.g. X86, SPARC in TSO mode) no such instruction is necessary, so
      MO_ReadBarrier is simply erased. However, such an instruction is necessary on
      weakly ordered machines, e.g. ARM and PowerPC.
      
      Weam memory ordering has consequences for how closures are observed and mutated.
      For example, consider a closure that needs to be upda...
      11bac115
  37. 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
  38. 09 Jun, 2019 1 commit
  39. 14 Apr, 2019 1 commit