1. 19 Apr, 2011 1 commit
  2. 12 Apr, 2011 1 commit
    • Simon Marlow's avatar
      Change the way module initialisation is done (#3252, #4417) · a52ff761
      Simon Marlow authored
      Previously the code generator generated small code fragments labelled
      with __stginit_M for each module M, and these performed whatever
      initialisation was necessary for that module and recursively invoked
      the initialisation functions for imported modules.  This appraoch had
      drawbacks:
      
       - FFI users had to call hs_add_root() to ensure the correct
         initialisation routines were called.  This is a non-standard,
         and ugly, API.
      
       - unless we were using -split-objs, the __stginit dependencies would
         entail linking the whole transitive closure of modules imported,
         whether they were actually used or not.  In an extreme case (#4387,
         #4417), a module from GHC might be imported for use in Template
         Haskell or an annotation, and that would force the whole of GHC to
         be needlessly linked into the final executable.
      
      So now instead we do our initialisation with C functions marked with
      __attribute__((constructor)), which are automatically invoked at
      program startup time (or DSO load-time).  The C initialisers are
      emitted into the stub.c file.  This means that every time we compile
      with -prof or -hpc, we now get a stub file, but thanks to #3687 that
      is now invisible to the user.
      
      There are some refactorings in the RTS (particularly for HPC) to
      handle the fact that initialisers now get run earlier than they did
      before.
      
      The __stginit symbols are still generated, and the hs_add_root()
      function still exists (but does nothing), for backwards compatibility.
      a52ff761
  3. 08 Apr, 2011 1 commit
    • Simon Marlow's avatar
      Force re-linking if the options have changed (#4451) · 814edf44
      Simon Marlow authored
      A common sequence of commands (at least for me) is this:
      
      $ ghc hello
      1 of 1] Compiling Main             ( hello.hs, hello.o )
      Linking hello ...
      $ ./hello +RTS -s
      hello: Most RTS options are disabled. Link with -rtsopts to enable them.
      $ ghc hello -rtsopts
      $
      
      grr, nothing happened.  I could use -fforce-recomp, but if this was a
      large program I probably don't want to recompile it all again, so:
      
      $ rm hello
      removed `hello'
      $ ghc hello -rtsopts
      Linking hello ...
      $ ./hello +RTS -s
      ./hello +RTS -s
      Hello World!
                51,264 bytes allocated in the heap
                 2,904 bytes copied during GC
                43,808 bytes maximum residency (1 sample(s))
                17,632 bytes maximum slop
      etc.
      
      With this patch, GHC notices when the options have changed and forces
      a relink, so you don't need to rm the binary or use -fforce-recomp.
      This is done by adding the pertinent stuff to the binary in a special
      section called ".debug-ghc-link-info":
      
      $ readelf -p .debug-ghc-link-info ./hello
      String dump of section 'ghc-linker-opts':
        [     0]  (["-lHSbase-4.3.1.0","-lHSinteger-gmp-0.2.0.2","-lgmp","-lHSghc-prim-0.2.0.0","-lHSrts","-lm","-lrt","-ldl","-u","ghczmprim_GHCziTypes_Izh_static_info","-u","ghczmprim_GHCziTypes_Czh_static_info","-u","ghczmprim_GHCziTypes_Fzh_static_info","-u","ghczmprim_GHCziTypes_Dzh_static_info","-u","base_GHCziPtr_Ptr_static_info","-u","base_GHCziWord_Wzh_static_info","-u","base_GHCziInt_I8zh_static_info","-u","base_GHCziInt_I16zh_static_info","-u","base_GHCziInt_I32zh_static_info","-u","base_GHCziInt_I64zh_static_info","-u","base_GHCziWord_W8zh_static_info","-u","base_GHCziWord_W16zh_static_info","-u","base_GHCziWord_W32zh_static_info","-u","base_GHCziWord_W64zh_static_info","-u","base_GHCziStable_StablePtr_static_info","-u","ghczmprim_GHCziTypes_Izh_con_info","-u","ghczmprim_GHCziTypes_Czh_con_info","-u","ghczmprim_GHCziTypes_Fzh_con_info","-u","ghczmprim_GHCziTypes_Dzh_con_info","-u","base_GHCziPtr_Ptr_con_info","-u","base_GHCziPtr_FunPtr_con_info","-u","base_GHCziStable_StablePtr_con_info","-u","ghczmprim_GHCziTypes_False_closure","-u","ghczmprim_GHCziTypes_True_closure","-u","base_GHCziPack_unpackCString_closure","-u","base_GHCziIOziException_stackOverflow_closure","-u","base_GHCziIOziException_heapOverflow_closure","-u","base_ControlziExceptionziBase_nonTermination_closure","-u","base_GHCziIOziException_blockedIndefinitelyOnMVar_closure","-u","base_GHCziIOziException_blockedIndefinitelyOnSTM_closure","-u","base_ControlziExceptionziBase_nestedAtomically_closure","-u","base_GHCziWeak_runFinalizzerBatch_closure","-u","base_GHCziTopHandler_runIO_closure","-u","base_GHCziTopHandler_runNonIO_closure","-u","base_GHCziConcziIO_ensureIOManagerIsRunning_closure","-u","base_GHCziConcziSync_runSparks_closure","-u","base_GHCziConcziSignal_runHandlers_closure","-lHSffi"],Nothing,RtsOptsAll,False,[],[])
      
      And GHC itself uses the readelf command to extract it when deciding
      whether to relink.  The reason for the name ".debug-ghc-link-info" is
      that sections beginning with ".debug" are removed automatically by
      strip.
      
      This currently only works on Linux; Windows and OS X still have the
      old behaviour.
      814edf44
  4. 24 Jan, 2011 1 commit
    • Simon Marlow's avatar
      Merge in new code generator branch. · 889c084e
      Simon Marlow authored
      This changes the new code generator to make use of the Hoopl package
      for dataflow analysis.  Hoopl is a new boot package, and is maintained
      in a separate upstream git repository (as usual, GHC has its own
      lagging darcs mirror in http://darcs.haskell.org/packages/hoopl).
      
      During this merge I squashed recent history into one patch.  I tried
      to rebase, but the history had some internal conflicts of its own
      which made rebase extremely confusing, so I gave up. The history I
      squashed was:
      
        - Update new codegen to work with latest Hoopl
        - Add some notes on new code gen to cmm-notes
        - Enable Hoopl lag package.
        - Add SPJ note to cmm-notes
        - Improve GC calls on new code generator.
      
      Work in this branch was done by:
         - Milan Straka <fox@ucw.cz>
         - John Dias <dias@cs.tufts.edu>
         - David Terei <davidterei@gmail.com>
      
      Edward Z. Yang <ezyang@mit.edu> merged in further changes from GHC HEAD
      and fixed a few bugs.
      889c084e
  5. 14 Sep, 2010 1 commit
    • Ian Lynagh's avatar
      Remove (most of) the FiniteMap wrapper · e95ee1f7
      Ian Lynagh authored
      We still have
          insertList, insertListWith, deleteList
      which aren't in Data.Map, and
          foldRightWithKey
      which works around the fold(r)WithKey addition and deprecation.
      e95ee1f7
  6. 29 Oct, 2009 1 commit
  7. 20 Jun, 2009 1 commit
  8. 06 Feb, 2009 2 commits
    • Ian Lynagh's avatar
      8fd6a1ef
    • Ian Lynagh's avatar
      When generating C, don't pretend functions are data · 497302c4
      Ian Lynagh authored
      We used to generated things like:
          extern StgWordArray (newCAF) __attribute__((aligned (8)));
          ((void (*)(void *))(W_)&newCAF)((void *)R1.w);
      (which is to say, pretend that newCAF is some data, then cast it to a
      function and call it).
      This goes wrong on at least IA64, where:
          A function pointer on the ia64 does not point to the first byte of
          code. Intsead, it points to a structure that describes the function.
          The first quadword in the structure is the address of the first byte
          of code
      so we end up dereferencing function pointers one time too many, and
      segfaulting.
      497302c4
  9. 27 Nov, 2008 1 commit
    • Simon Marlow's avatar
      don't emit CmmComments for now · 1f03870f
      Simon Marlow authored
        - if the string contains */, we need to fix it (demonstrated by 
          building Cabal with -fvia-C)
        - the strings can get quite large, so we probably only want to
          inject comments when some debugging option is on.
      1f03870f
  10. 13 Oct, 2008 2 commits
    • dias@eecs.harvard.edu's avatar
      93d047a1
    • dias@eecs.harvard.edu's avatar
      Big collection of patches for the new codegen branch. · e6243a81
      dias@eecs.harvard.edu authored
      o Fixed bug that emitted the copy-in code for closure entry
        in the wrong place -- at the initialization of the closure.
      o Refactored some of the closure entry code.
      o Added code to check that no LocalRegs are live-in to a procedure
         -- trip up some buggy programs earlier
      o Fixed environment bindings for thunks
         -- we weren't (re)binding the free variables in a thunk
      o Fixed a bug in proc-point splitting that dropped some updates
        to the entry block in a procedure.
      o Fixed improper calls to code that generates CmmLit's for strings
      o New invariant on cg_loc in CgIdInfo: the expression is always tagged
      o Code to load free vars on entry to a thunk was (wrongly) placed before
        the heap check.
      o Some of the StgCmm code was redundantly passing around Id's
        along with CgIdInfo's; no more.
      o Initialize the LocalReg's that point to a closure before allocating and
        initializing the closure itself -- otherwise, we have problems with
        recursive closure bindings
      o BlockEnv and BlockSet types are now abstract.
      o Update frames:
        - push arguments in Old call area
        - keep track of the return sp in the FCode monad
        - keep the return sp in every call, tail call, and return
            (because it might be different at different call sites,
             e.g. tail calls to the gc after a heap check are performed
                  before pushing the update frame)
        - set the sp appropriately on returns and tail calls
      o Reduce call, tail call, and return to a single LastCall node
      o Added slow entry code, using different calling conventions on entry and tail call
      o More fixes to the calling convention code.
        The tricky stuff is all about the closure environment: it must be passed in R1,
        but in non-closures, there is no such argument, so we can't treat all arguments
        the same way: the closure environment is special. Maybe the right step forward
        would be to define a different calling convention for closure arguments.
      o Let-no-escapes need to be emitted out-of-line -- otherwise, we drop code.
      o Respect RTS requirement of word alignment for pointers
        My stack allocation can pack sub-word values into a single word on the stack,
        but it wasn't requiring word-alignment for pointers. It does now,
        by word-aligning both pointer registers and call areas.
      o CmmLint was over-aggresively ruling out non-word-aligned memory references,
        which may be kosher now that we can spill small values into a single word.
      o Wrong label order on a conditional branch when compiling switches.
      o void args weren't dropped in many cases.
        To help prevent this kind of mistake, I defined a NonVoid wrapper,
        which I'm applying only to Id's for now, although there are probably
        other good candidates.
      o A little code refactoring: separate modules for procpoint analysis splitting, 
        stack layout, and building infotables.
      o Stack limit check: insert along with the heap limit check, using a symbolic
        constant (a special CmmLit), then replace it when the stack layout is known.
      o Removed last node: MidAddToContext 
      o Adding block id as a literal: means that the lowering of the calling conventions
        no longer has to produce labels early, which was inhibiting common-block elimination.
        Will also make it easier for the non-procpoint-splitting path.
      o Info tables: don't try to describe the update frame!
      o Over aggressive use of NonVoid!!!!
        Don't drop the non-void args before setting the type of the closure!!!
      o Sanity checking:
        Added a pass to stub dead dead slots on the stack
        (only ~10 lines with the dataflow framework)
      o More sanity checking:
        Check that incoming pointer arguments are non-stubbed.
        Note: these checks are still subject to dead-code removal, but they should
        still be quite helpful.
      o Better sanity checking: why stop at function arguments?
        Instead, in mkAssign, check that _any_ assignment to a pointer type is non-null
        -- the sooner the crash, the easier it is to debug.
        Still need to add the debugging flag to turn these checks on explicitly.
      o Fixed yet another calling convention bug.
        This time, the calls to the GC were wrong. I've added a new convention
        for GC calls and invoked it where appropriate.
        We should really straighten out the calling convention stuff:
          some of the code (and documentation) is spread across the compiler,
          and there's some magical use of the node register that should really
          be handled (not avoided) by calling conventions.
      o Switch bug: the arms in mkCmmLitSwitch weren't returning to a single join point.
      o Environment shadowing problem in Stg->Cmm:
        When a closure f is bound at the top-level, we should not bind f to the
        node register on entry to the closure.
        Why? Because if the body of f contains a let-bound closure g that refers
        to f, we want to make sure that it refers to the static closure for f.
        Normally, this would all be fine, because when we compile a closure,
        we rebind free variables in the environment. But f doesn't look like
        a free variable because it's a static value. So, the binding for f
        remains in the environment when we compile g, inconveniently referring
        to the wrong thing.
        Now, I bind the variable in the local environment only if the closure is not
        bound at the top level. It's still okay to make assumptions about the
        node holding the closure environment; we just won't find the binding
        in the environment, so code that names the closure will now directly
        get the label of the static closure, not the node register holding a
        pointer to the static closure.
      o Don't generate bogus Cmm code containing SRTs during the STG -> Cmm pass!
        The tables made reference to some labels that don't exist when we compute and
        generate the tables in the back end.
      o Safe foreign calls need some special treatment (at least until we have the integrated
        codegen). In particular:
        o they need info tables
        o they are not procpoints -- the successor had better be in the same procedure
        o we cannot (yet) implement the calling conventions early, which means we have
          to carry the calling-conv info all the way to the end
      o We weren't following the old convention when registering a module.
        Now, we use update frames to push any new modules that have to be registered
        and enter the youngest one on the stack.
        We also use the update frame machinery to specify that the return should pop
        the return address off the stack.
      o At each safe foreign call, an infotable must be at the bottom of the stack,
        and the TSO->sp must point to it.
      o More problems with void args in a direct call to a function:
        We were checking the args (minus voids) to check whether the call was saturated,
        which caused problems when the function really wasn't saturated because it
        took an extra void argument.
      o Forgot to distinguish integer != from floating != during Stg->Cmm
      o Updating slotEnv and areaMap to include safe foreign calls
        The dataflow analyses that produce the slotEnv and areaMap give
        results for each basic block, but we also need the results for
        a safe foreign call, which is a middle node.
        After running the dataflow analysis, we have another pass that
        updates the results to includ any safe foreign calls.
      o Added a static flag for the debugging technique that inserts
        instructions to stub dead slots on the stack and crashes when
        a stubbed value is loaded into a pointer-typed LocalReg.
      o C back end expects to see return continuations before their call sites.
        Sorted the flowgraphs appropriately after splitting.
      o PrimOp calling conventions are special -- unlimited registers, no stack
        Yet another calling convention...
      o More void value problems: if the RHS of a case arm is a void-typed variable,
        don't try to return it.
      o When calling some primOp, they may allocate memory; if so, we need to
        do a heap check when we return from the call.
      e6243a81
  11. 14 Aug, 2008 1 commit
    • dias@eecs.harvard.edu's avatar
      Merging in the new codegen branch · 176fa33f
      dias@eecs.harvard.edu authored
      This merge does not turn on the new codegen (which only compiles
      a select few programs at this point),
      but it does introduce some changes to the old code generator.
      
      The high bits:
      1. The Rep Swamp patch is finally here.
         The highlight is that the representation of types at the
         machine level has changed.
         Consequently, this patch contains updates across several back ends.
      2. The new Stg -> Cmm path is here, although it appears to have a
         fair number of bugs lurking.
      3. Many improvements along the CmmCPSZ path, including:
         o stack layout
         o some code for infotables, half of which is right and half wrong
         o proc-point splitting
      176fa33f
  12. 18 Nov, 2008 1 commit
    • Simon Marlow's avatar
      Add optional eager black-holing, with new flag -feager-blackholing · d600bf7a
      Simon Marlow authored
      Eager blackholing can improve parallel performance by reducing the
      chances that two threads perform the same computation.  However, it
      has a cost: one extra memory write per thunk entry.  
      
      To get the best results, any code which may be executed in parallel
      should be compiled with eager blackholing turned on.  But since
      there's a cost for sequential code, we make it optional and turn it on
      for the parallel package only.  It might be a good idea to compile
      applications (or modules) with parallel code in with
      -feager-blackholing.
      
      ToDo: document -feager-blackholing.
      d600bf7a
  13. 29 May, 2008 1 commit
    • dias@eecs.harvard.edu's avatar
      Replacing copyins and copyouts with data-movement instructions · 0d80489c
      dias@eecs.harvard.edu authored
      o Moved BlockId stuff to a new file to avoid module recursion
      o Defined stack areas for parameter-passing locations and spill slots
      o Part way through replacing copy in and copy out nodes
        - added movement instructions for stack pointer
        - added movement instructions for call and return parameters
          (but not with the proper calling conventions)
      o Inserting spills and reloads for proc points is now procpoint-aware
        (it was relying on the presence of a CopyIn node as a proxy for
         procpoint knowledge)
      o Changed ZipDataflow to expect AGraphs (instead of being polymorphic in
         the type of graph)
      0d80489c
  14. 14 May, 2008 1 commit
    • Simon Marlow's avatar
      FIX #2276: foreign import stdcall "&foo" doesn't work · bca74f3e
      Simon Marlow authored
      This turned out not to be too hard, just a matter of figuring out the
      correct argument list size by peeking inside FunPtr's type argument,
      and in the C backend we have to emit an appropriate prototype for the label.
      bca74f3e
  15. 12 May, 2008 2 commits
  16. 03 May, 2008 2 commits
  17. 23 Apr, 2008 1 commit
  18. 12 Apr, 2008 1 commit
  19. 09 Apr, 2008 1 commit
  20. 02 Apr, 2008 1 commit
    • Simon Marlow's avatar
      Do not #include external header files when compiling via C · c245355e
      Simon Marlow authored
      This has several advantages:
      
       - -fvia-C is consistent with -fasm with respect to FFI declarations:
         both bind to the ABI, not the API.
      
       - foreign calls can now be inlined freely across module boundaries, since
         a header file is not required when compiling the call.
      
       - bootstrapping via C will be more reliable, because this difference
         in behavour between the two backends has been removed.
      
      There is one disadvantage:
      
       - we get no checking by the C compiler that the FFI declaration
         is correct.
      
      So now, the c-includes field in a .cabal file is always ignored by
      GHC, as are header files specified in an FFI declaration.  This was
      previously the case only for -fasm compilations, now it is also the
      case for -fvia-C too.
      c245355e
  21. 29 Mar, 2008 1 commit
  22. 06 Feb, 2008 1 commit
  23. 04 Jan, 2008 1 commit
  24. 08 Nov, 2007 1 commit
  25. 21 Sep, 2007 1 commit
  26. 07 Sep, 2007 1 commit
    • nr@eecs.harvard.edu's avatar
      a good deal of salutory renaming · fd8d0411
      nr@eecs.harvard.edu authored
      I've renamed a number of type and data constructors within Cmm so that
      the names used in the compiler may more closely reflect the C--
      specification 2.1.  I've done a bit of other renaming as well.
      Highlights:
      
        CmmFormal and CmmActual now bear a CmmKind (which for now is a
                                                    MachHint as before)
        CmmFormals = [CmmFormal] and CmmActuals = [CmmActual]
        
        suitable changes have been made to both code and nonterminals in the
        Cmm parser (which is as yet untested)
      
        For reasons I don't understand, parts of the code generator use a
        sequence of 'formal parameters' with no C-- kinds.  For these we now
        have the types
          type CmmFormalWithoutKind   = LocalReg
          type CmmFormalsWithoutKinds = [CmmFormalWithoutKind]
      
        A great many appearances of (Tau, MachHint) have been simplified to
        the appropriate CmmFormal or CmmActual, though I'm sure there are
        more opportunities.
      
        Kind and its data constructors are now renamed to
           data GCKind = GCKindPtr | GCKindNonPtr 
        to avoid confusion with the Kind used in the type checker and with CmmKind.
      
      Finally, in a somewhat unrelated bit (and in honor of Simon PJ, who
      thought of the name), the Whalley/Davidson 'transaction limit' is now
      called 'OptimizationFuel' with the net effect that there are no longer
      two unrelated uses of the abbreviation 'tx'.
      
      fd8d0411
  27. 05 Sep, 2007 1 commit
    • nr@eecs.harvard.edu's avatar
      change of representation for GenCmm, GenCmmTop, CmmProc · 16dc208a
      nr@eecs.harvard.edu authored
      The type parameter to a C-- procedure now represents a control-flow
      graph, not a single instruction.  The newtype ListGraph preserves the 
      current representation while enabling other representations and a
      sensible way of prettyprinting.  Except for a few changes in the
      prettyprinter the new compiler binary should be bit-for-bit identical
      to the old.
      16dc208a
  28. 04 Sep, 2007 1 commit
  29. 03 Sep, 2007 1 commit
  30. 01 Sep, 2007 1 commit
  31. 20 Aug, 2007 1 commit
  32. 09 Aug, 2007 1 commit
  33. 31 Jul, 2007 1 commit
    • Clemens Fruhwirth's avatar
      Change the strategy to determine dynamic data access · 81b2276f
      Clemens Fruhwirth authored
      Instead of attaching the information whether a Label is going to be
      accessed dynamically or not (distinction between IdLabel/DynLabel and
      additional flags in ModuleInitLabel and PlainModuleInitLabel), we hand
      dflags through the CmmOpt monad and the NatM monad. Before calling
      labelDynamic in PositionIndependentCode, we extract thisPackage from
      dflags and supply the current package to labelDynamic, so it can take
      this information into account instead of extracting it from the labels
      itself. This simplifies a lot of code in codeGen that just hands
      through this_pkg.
      81b2276f
  34. 27 Jul, 2007 1 commit
    • Simon Marlow's avatar
      Pointer Tagging · 6015a94f
      Simon Marlow authored
        
      This patch implements pointer tagging as per our ICFP'07 paper "Faster
      laziness using dynamic pointer tagging".  It improves performance by
      10-15% for most workloads, including GHC itself.
      
      The original patches were by Alexey Rodriguez Yakushev
      <mrchebas@gmail.com>, with additions and improvements by me.  I've
      re-recorded the development as a single patch.
      
      The basic idea is this: we use the low 2 bits of a pointer to a heap
      object (3 bits on a 64-bit architecture) to encode some information
      about the object pointed to.  For a constructor, we encode the "tag"
      of the constructor (e.g. True vs. False), for a function closure its
      arity.  This enables some decisions to be made without dereferencing
      the pointer, which speeds up some common operations.  In particular it
      enables us to avoid costly indirect jumps in many cases.
      
      More information in the commentary:
      
      http://hackage.haskell.org/trac/ghc/wiki/Commentary/Rts/HaskellExecution/PointerTagging
      6015a94f
  35. 18 Jul, 2007 1 commit
    • Ian Lynagh's avatar
      Fixes for the unreg build · 48fb2b52
      Ian Lynagh authored
      * Fix code output order when printing C so things are defined before
        they are used.
      * Generate _ret rather than _entry functions for INFO_TABLE_RET.
      * Use "ASSIGN_BaseReg" rather than "BaseReg =".
      48fb2b52
  36. 27 Jun, 2007 1 commit