2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[CodeGen]{@CodeGen@: main module of the code generator}
6 This module says how things get going at the top level.
8 @codeGen@ is the interface to the outside world. The \tr{cgTop*}
9 functions drive the mangling of top-level bindings.
11 %************************************************************************
13 \subsection[codeGen-outside-interface]{The code generator's offering to the world}
15 %************************************************************************
18 module CodeGen ( codeGen ) where
20 #include "HsVersions.h"
22 import DriverState ( v_Build_tag, v_MainModIs )
24 -- Kludge (??) so that CgExpr is reached via at least one non-SOURCE
25 -- import. Before, that wasn't the case, and CM therefore didn't
26 -- bother to compile it.
27 import CgExpr ( {-NOTHING!-} ) -- DO NOT DELETE THIS IMPORT
30 import CgBindery ( CgIdInfo, addBindC, addBindsC, getCgIdInfo,
32 import CgClosure ( cgTopRhsClosure )
33 import CgCon ( cgTopRhsCon, cgTyCon )
34 import CgUtils ( cmmRegOffW, emitRODataLits, cmmNeWord, emitRtsCall )
36 import CLabel ( mkSRTLabel, mkClosureLabel, moduleRegdLabel,
37 mkPlainModuleInitLabel, mkModuleInitLabel )
39 import CmmUtils ( zeroCLit, mkIntCLit, mkLblExpr )
40 import PprCmm ( pprCmms )
41 import MachOp ( wordRep, MachHint(..) )
44 import PrelNames ( gHC_PRIM, rOOT_MAIN, mAIN_Name, pREL_TOP_HANDLER )
45 import CmdLineOpts ( DynFlags, DynFlag(..), opt_EnsureSplittableC,
48 import HscTypes ( ForeignStubs(..), TypeEnv, typeEnvTyCons )
49 import CostCentre ( CollectedCCs )
50 import Id ( Id, idName, setIdName )
51 import Name ( nameSrcLoc, nameOccName, nameUnique, isInternalName, mkExternalName )
52 import OccName ( mkLocalOcc )
53 import TyCon ( isDataTyCon )
54 import Module ( Module, mkModuleName )
55 import ErrUtils ( dumpIfSet_dyn, showPass )
56 import Panic ( assertPanic, trace )
57 import qualified Module ( moduleName )
63 import DATA_IOREF ( readIORef )
71 -> [Module] -- directly-imported modules
72 -> CollectedCCs -- (Local/global) cost-centres needing declaring/registering.
73 -> [(StgBinding,[(Id,[Id])])] -- Bindings to convert, with SRTs
76 codeGen dflags this_mod type_env foreign_stubs imported_mods
77 cost_centre_info stg_binds
79 { showPass dflags "CodeGen"
80 ; way <- readIORef v_Build_tag
81 ; mb_main_mod <- readIORef v_MainModIs
83 ; let tycons = typeEnvTyCons type_env
84 data_tycons = filter isDataTyCon tycons
87 -- ; mapM_ (\x -> seq x (return ())) data_tycons
89 ; code_stuff <- initC this_mod $ do
90 { cmm_binds <- mapM (getCmm . cgTopBinding) stg_binds
91 ; cmm_tycons <- mapM cgTyCon data_tycons
92 ; cmm_init <- getCmm (mkModuleInit way cost_centre_info
94 foreign_stubs imported_mods)
95 ; return (cmm_binds ++ concat cmm_tycons ++ [cmm_init])
97 -- Put datatype_stuff after code_stuff, because the
98 -- datatype closure table (for enumeration types) to
99 -- (say) PrelBase_True_closure, which is defined in
102 ; dumpIfSet_dyn dflags Opt_D_dump_cmm "Cmm" (pprCmms code_stuff)
104 ; return code_stuff }
107 %************************************************************************
109 \subsection[codegen-init]{Module initialisation code}
111 %************************************************************************
113 /* -----------------------------------------------------------------------------
114 Module initialisation
116 The module initialisation code looks like this, roughly:
119 JMP_(__stginit_Foo_1_p)
122 FN(__stginit_Foo_1_p) {
126 We have one version of the init code with a module version and the
127 'way' attached to it. The version number helps to catch cases
128 where modules are not compiled in dependency order before being
129 linked: if a module has been compiled since any modules which depend on
130 it, then the latter modules will refer to a different version in their
131 init blocks and a link error will ensue.
133 The 'way' suffix helps to catch cases where modules compiled in different
134 ways are linked together (eg. profiled and non-profiled).
136 We provide a plain, unadorned, version of the module init code
137 which just jumps to the version with the label and way attached. The
138 reason for this is that when using foreign exports, the caller of
139 startupHaskell() must supply the name of the init function for the "top"
140 module in the program, and we don't want to require that this name
141 has the version and way info appended to it.
142 -------------------------------------------------------------------------- */
144 We initialise the module tree by keeping a work-stack,
146 * that grows downward
147 * Sp points to the last occupied slot
152 :: String -- the "way"
153 -> CollectedCCs -- cost centre info
155 -> Maybe String -- Just m ==> we have flag: -main-is Foo.baz
159 mkModuleInit way cost_centre_info this_mod mb_main_mod foreign_stubs imported_mods
162 -- Allocate the static boolean that records if this
163 -- module has been registered already
164 ; emitData Data [CmmDataLabel moduleRegdLabel,
165 CmmStaticLit zeroCLit]
167 ; emitSimpleProc real_init_lbl $ do
168 { -- The return-code pops the work stack by
169 -- incrementing Sp, and then jumpd to the popped item
170 ret_blk <- forkLabelledCode $ stmtsC
171 [ CmmAssign spReg (cmmRegOffW spReg 1)
172 , CmmJump (CmmLoad (cmmRegOffW spReg (-1)) wordRep) [] ]
174 ; init_blk <- forkLabelledCode $ do
175 { mod_init_code; stmtC (CmmBranch ret_blk) }
177 ; stmtC (CmmCondBranch (cmmNeWord (CmmLit zeroCLit) mod_reg_val)
179 ; stmtC (CmmBranch init_blk)
183 -- Make the "plain" procedure jump to the "real" init procedure
184 ; emitSimpleProc plain_init_lbl jump_to_init
186 -- When compiling the module in which the 'main' function lives,
187 -- (that is, Module.moduleName this_mod == main_mod_name)
188 -- we inject an extra stg_init procedure for stg_init_ZCMain, for the
189 -- RTS to invoke. We must consult the -main-is flag in case the
190 -- user specified a different function to Main.main
191 ; whenC (Module.moduleName this_mod == main_mod_name)
192 (emitSimpleProc plain_main_init_lbl jump_to_init)
195 plain_init_lbl = mkPlainModuleInitLabel this_mod
196 real_init_lbl = mkModuleInitLabel this_mod way
197 plain_main_init_lbl = mkPlainModuleInitLabel rOOT_MAIN
199 jump_to_init = stmtC (CmmJump (mkLblExpr real_init_lbl) [])
201 mod_reg_val = CmmLoad (mkLblExpr moduleRegdLabel) wordRep
203 main_mod_name = case mb_main_mod of
204 Just mod_name -> mkModuleName mod_name
207 -- Main refers to GHC.TopHandler.runIO, so make sure we call the
208 -- init function for GHC.TopHandler.
210 | Module.moduleName this_mod == main_mod_name = [pREL_TOP_HANDLER]
214 { -- Set mod_reg to 1 to record that we've been here
215 stmtC (CmmStore (mkLblExpr moduleRegdLabel) (CmmLit (mkIntCLit 1)))
217 -- Now do local stuff
218 ; registerForeignExports foreign_stubs
219 ; initCostCentres cost_centre_info
220 ; mapCs (registerModuleImport way) (imported_mods++extra_imported_mods)
224 -----------------------
225 registerModuleImport :: String -> Module -> Code
226 registerModuleImport way mod
229 | otherwise -- Push the init procedure onto the work stack
230 = stmtsC [ CmmAssign spReg (cmmRegOffW spReg (-1))
231 , CmmStore (CmmReg spReg) (mkLblExpr (mkModuleInitLabel mod way)) ]
233 -----------------------
234 registerForeignExports :: ForeignStubs -> Code
235 registerForeignExports NoStubs
237 registerForeignExports (ForeignStubs _ _ _ fe_bndrs)
238 = mapM_ mk_export_register fe_bndrs
240 mk_export_register bndr
241 = emitRtsCall SLIT("getStablePtr")
242 [ (CmmLit (CmmLabel (mkClosureLabel (idName bndr))), PtrHint) ]
247 Cost-centre profiling: Besides the usual stuff, we must produce
248 declarations for the cost-centres defined in this module;
250 (The local cost-centres involved in this are passed into the
254 initCostCentres :: CollectedCCs -> Code
255 -- Emit the declarations, and return code to register them
256 initCostCentres (local_CCs, ___extern_CCs, singleton_CCSs)
257 | not opt_SccProfilingOn = nopC
259 = do { mapM_ emitCostCentreDecl local_CCs
260 ; mapM_ emitCostCentreStackDecl singleton_CCSs
261 ; mapM_ emitRegisterCC local_CCs
262 ; mapM_ emitRegisterCCS singleton_CCSs
266 %************************************************************************
268 \subsection[codegen-top-bindings]{Converting top-level STG bindings}
270 %************************************************************************
272 @cgTopBinding@ is only used for top-level bindings, since they need
273 to be allocated statically (not in the heap) and need to be labelled.
274 No unboxed bindings can happen at top level.
276 In the code below, the static bindings are accumulated in the
277 @MkCgState@, and transferred into the ``statics'' slot by @forkStatics@.
278 This is so that we can write the top level processing in a compositional
279 style, with the increasing static environment being plumbed as a state
283 cgTopBinding :: (StgBinding,[(Id,[Id])]) -> Code
284 cgTopBinding (StgNonRec id rhs, srts)
285 = do { id' <- maybeExternaliseId id
286 ; mapM_ (mkSRT [id']) srts
287 ; (id,info) <- cgTopRhs id' rhs
288 ; addBindC id info -- Add the *un-externalised* Id to the envt,
289 -- so we find it when we look up occurrences
292 cgTopBinding (StgRec pairs, srts)
293 = do { let (bndrs, rhss) = unzip pairs
294 ; bndrs' <- mapFCs maybeExternaliseId bndrs
295 ; let pairs' = zip bndrs' rhss
296 ; mapM_ (mkSRT bndrs') srts
297 ; new_binds <- fixC (\ new_binds -> do
298 { addBindsC new_binds
299 ; mapFCs ( \ (b,e) -> cgTopRhs b e ) pairs' })
302 mkSRT :: [Id] -> (Id,[Id]) -> Code
303 mkSRT these (id,[]) = nopC
305 = do { ids <- mapFCs remap ids
307 ; emitRODataLits (mkSRTLabel (idName id))
308 (map (CmmLabel . mkClosureLabel . idName) ids)
311 -- Sigh, better map all the ids against the environment in
312 -- case they've been externalised (see maybeExternaliseId below).
313 remap id = case filter (==id) these of
314 (id':_) -> returnFC id'
315 [] -> do { info <- getCgIdInfo id; return (cgIdInfoId info) }
317 -- Urgh! I tried moving the forkStatics call from the rhss of cgTopRhs
318 -- to enclose the listFCs in cgTopBinding, but that tickled the
319 -- statics "error" call in initC. I DON'T UNDERSTAND WHY!
321 cgTopRhs :: Id -> StgRhs -> FCode (Id, CgIdInfo)
322 -- The Id is passed along for setting up a binding...
323 -- It's already been externalised if necessary
325 cgTopRhs bndr (StgRhsCon cc con args)
326 = forkStatics (cgTopRhsCon bndr con args)
328 cgTopRhs bndr (StgRhsClosure cc bi fvs upd_flag srt args body)
329 = ASSERT(null fvs) -- There should be no free variables
330 setSRTLabel (mkSRTLabel (idName bndr)) $
331 forkStatics (cgTopRhsClosure bndr cc bi srt upd_flag args body)
335 %************************************************************************
337 \subsection{Stuff to support splitting}
339 %************************************************************************
341 If we're splitting the object, we need to externalise all the top-level names
342 (and then make sure we only use the externalised one in any C label we use
343 which refers to this name).
346 maybeExternaliseId :: Id -> FCode Id
347 maybeExternaliseId id
348 | opt_EnsureSplittableC, -- Externalise the name for -split-objs
349 isInternalName name = do { mod <- moduleName
350 ; returnFC (setIdName id (externalise mod)) }
351 | otherwise = returnFC id
353 externalise mod = mkExternalName uniq mod new_occ Nothing loc
355 uniq = nameUnique name
356 new_occ = mkLocalOcc uniq (nameOccName name)
357 loc = nameSrcLoc name
358 -- We want to conjure up a name that can't clash with any
359 -- existing name. So we generate
361 -- where 243 is the unique.