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 -- Kludge (??) so that CgExpr is reached via at least one non-SOURCE
23 -- import. Before, that wasn't the case, and CM therefore didn't
24 -- bother to compile it.
25 import CgExpr ( {-NOTHING!-} ) -- DO NOT DELETE THIS IMPORT
28 import CgBindery ( CgIdInfo, addBindC, addBindsC, getCgIdInfo,
30 import CgClosure ( cgTopRhsClosure )
31 import CgCon ( cgTopRhsCon, cgTyCon )
32 import CgUtils ( cmmRegOffW, emitRODataLits, cmmNeWord, emitRtsCall )
36 import CmmUtils ( zeroCLit, mkIntCLit, mkLblExpr )
37 import PprCmm ( pprCmms )
38 import MachOp ( wordRep, MachHint(..) )
41 import PrelNames ( gHC_PRIM, rOOT_MAIN, mAIN, pREL_TOP_HANDLER )
42 import DynFlags ( DynFlags(..), DynFlag(..), dopt )
43 import StaticFlags ( opt_SccProfilingOn )
45 import HscTypes ( ForeignStubs(..), TypeEnv, typeEnvTyCons )
46 import CostCentre ( CollectedCCs )
47 import Id ( Id, idName, setIdName )
48 import Name ( nameSrcLoc, nameOccName, nameUnique, isInternalName, mkExternalName )
49 import OccName ( mkLocalOcc )
50 import TyCon ( isDataTyCon )
51 import Module ( Module, mkModule )
52 import ErrUtils ( dumpIfSet_dyn, showPass )
53 import Panic ( assertPanic )
59 import DATA_IOREF ( readIORef )
67 -> [Module] -- directly-imported modules
68 -> CollectedCCs -- (Local/global) cost-centres needing declaring/registering.
69 -> [(StgBinding,[(Id,[Id])])] -- Bindings to convert, with SRTs
72 codeGen dflags this_mod type_env foreign_stubs imported_mods
73 cost_centre_info stg_binds
75 { showPass dflags "CodeGen"
76 ; let way = buildTag dflags
77 mb_main_mod = mainModIs dflags
79 ; let tycons = typeEnvTyCons type_env
80 data_tycons = filter isDataTyCon tycons
83 -- ; mapM_ (\x -> seq x (return ())) data_tycons
85 ; code_stuff <- initC dflags this_mod $ do
86 { cmm_binds <- mapM (getCmm . cgTopBinding dflags) stg_binds
87 ; cmm_tycons <- mapM cgTyCon data_tycons
88 ; cmm_init <- getCmm (mkModuleInit dflags way cost_centre_info
90 foreign_stubs imported_mods)
91 ; return (cmm_binds ++ concat cmm_tycons
92 ++ if opt_SccProfilingOn
93 #if defined(mingw32_HOST_OS)
99 -- Put datatype_stuff after code_stuff, because the
100 -- datatype closure table (for enumeration types) to
101 -- (say) PrelBase_True_closure, which is defined in
104 ; dumpIfSet_dyn dflags Opt_D_dump_cmm "Cmm" (pprCmms code_stuff)
106 ; return code_stuff }
109 %************************************************************************
111 \subsection[codegen-init]{Module initialisation code}
113 %************************************************************************
115 /* -----------------------------------------------------------------------------
116 Module initialisation
118 The module initialisation code looks like this, roughly:
121 JMP_(__stginit_Foo_1_p)
124 FN(__stginit_Foo_1_p) {
128 We have one version of the init code with a module version and the
129 'way' attached to it. The version number helps to catch cases
130 where modules are not compiled in dependency order before being
131 linked: if a module has been compiled since any modules which depend on
132 it, then the latter modules will refer to a different version in their
133 init blocks and a link error will ensue.
135 The 'way' suffix helps to catch cases where modules compiled in different
136 ways are linked together (eg. profiled and non-profiled).
138 We provide a plain, unadorned, version of the module init code
139 which just jumps to the version with the label and way attached. The
140 reason for this is that when using foreign exports, the caller of
141 startupHaskell() must supply the name of the init function for the "top"
142 module in the program, and we don't want to require that this name
143 has the version and way info appended to it.
144 -------------------------------------------------------------------------- */
146 We initialise the module tree by keeping a work-stack,
148 * that grows downward
149 * Sp points to the last occupied slot
155 -> String -- the "way"
156 -> CollectedCCs -- cost centre info
158 -> Maybe String -- Just m ==> we have flag: -main-is Foo.baz
162 mkModuleInit dflags way cost_centre_info this_mod mb_main_mod foreign_stubs imported_mods
165 -- Allocate the static boolean that records if this
166 -- module has been registered already
167 ; emitData Data [CmmDataLabel moduleRegdLabel,
168 CmmStaticLit zeroCLit]
170 ; emitSimpleProc real_init_lbl $ do
171 { -- The return-code pops the work stack by
172 -- incrementing Sp, and then jumpd to the popped item
173 ret_blk <- forkLabelledCode $ stmtsC
174 [ CmmAssign spReg (cmmRegOffW spReg 1)
175 , CmmJump (CmmLoad (cmmRegOffW spReg (-1)) wordRep) [] ]
177 ; init_blk <- forkLabelledCode $ do
178 { mod_init_code; stmtC (CmmBranch ret_blk) }
180 ; stmtC (CmmCondBranch (cmmNeWord (CmmLit zeroCLit) mod_reg_val)
182 ; stmtC (CmmBranch init_blk)
186 -- Make the "plain" procedure jump to the "real" init procedure
187 ; emitSimpleProc plain_init_lbl jump_to_init
189 -- When compiling the module in which the 'main' function lives,
190 -- (that is, this_mod == main_mod)
191 -- we inject an extra stg_init procedure for stg_init_ZCMain, for the
192 -- RTS to invoke. We must consult the -main-is flag in case the
193 -- user specified a different function to Main.main
194 ; whenC (this_mod == main_mod)
195 (emitSimpleProc plain_main_init_lbl jump_to_init)
198 plain_init_lbl = mkPlainModuleInitLabel dflags this_mod
199 real_init_lbl = mkModuleInitLabel dflags this_mod way
200 plain_main_init_lbl = mkPlainModuleInitLabel dflags rOOT_MAIN
202 jump_to_init = stmtC (CmmJump (mkLblExpr real_init_lbl) [])
204 mod_reg_val = CmmLoad (mkLblExpr moduleRegdLabel) wordRep
206 main_mod = case mb_main_mod of
207 Just mod_name -> mkModule mod_name
210 -- Main refers to GHC.TopHandler.runIO, so make sure we call the
211 -- init function for GHC.TopHandler.
213 | this_mod == main_mod = [pREL_TOP_HANDLER]
217 { -- Set mod_reg to 1 to record that we've been here
218 stmtC (CmmStore (mkLblExpr moduleRegdLabel) (CmmLit (mkIntCLit 1)))
220 -- Now do local stuff
221 #if defined(mingw32_HOST_OS)
222 ; registerForeignExports foreign_stubs
224 ; initCostCentres cost_centre_info
225 ; mapCs (registerModuleImport dflags way)
226 (imported_mods++extra_imported_mods)
230 -----------------------
231 registerModuleImport :: DynFlags -> String -> Module -> Code
232 registerModuleImport dflags way mod
235 | otherwise -- Push the init procedure onto the work stack
236 = stmtsC [ CmmAssign spReg (cmmRegOffW spReg (-1))
237 , CmmStore (CmmReg spReg) (mkLblExpr (mkModuleInitLabel dflags mod way)) ]
239 -----------------------
240 registerForeignExports :: ForeignStubs -> Code
241 registerForeignExports NoStubs
243 registerForeignExports (ForeignStubs _ _ _ fe_bndrs)
244 = mapM_ mk_export_register fe_bndrs
246 mk_export_register bndr
247 = emitRtsCall SLIT("getStablePtr")
248 [ (CmmLit (CmmLabel (mkLocalClosureLabel (idName bndr))),
254 Cost-centre profiling: Besides the usual stuff, we must produce
255 declarations for the cost-centres defined in this module;
257 (The local cost-centres involved in this are passed into the
261 initCostCentres :: CollectedCCs -> Code
262 -- Emit the declarations, and return code to register them
263 initCostCentres (local_CCs, ___extern_CCs, singleton_CCSs)
264 | not opt_SccProfilingOn = nopC
266 = do { mapM_ emitCostCentreDecl local_CCs
267 ; mapM_ emitCostCentreStackDecl singleton_CCSs
268 ; mapM_ emitRegisterCC local_CCs
269 ; mapM_ emitRegisterCCS singleton_CCSs
273 %************************************************************************
275 \subsection[codegen-top-bindings]{Converting top-level STG bindings}
277 %************************************************************************
279 @cgTopBinding@ is only used for top-level bindings, since they need
280 to be allocated statically (not in the heap) and need to be labelled.
281 No unboxed bindings can happen at top level.
283 In the code below, the static bindings are accumulated in the
284 @MkCgState@, and transferred into the ``statics'' slot by @forkStatics@.
285 This is so that we can write the top level processing in a compositional
286 style, with the increasing static environment being plumbed as a state
290 cgTopBinding :: DynFlags -> (StgBinding,[(Id,[Id])]) -> Code
291 cgTopBinding dflags (StgNonRec id rhs, srts)
292 = do { id' <- maybeExternaliseId dflags id
293 ; mapM_ (mkSRT dflags [id']) srts
294 ; (id,info) <- cgTopRhs id' rhs
295 ; addBindC id info -- Add the *un-externalised* Id to the envt,
296 -- so we find it when we look up occurrences
299 cgTopBinding dflags (StgRec pairs, srts)
300 = do { let (bndrs, rhss) = unzip pairs
301 ; bndrs' <- mapFCs (maybeExternaliseId dflags) bndrs
302 ; let pairs' = zip bndrs' rhss
303 ; mapM_ (mkSRT dflags bndrs') srts
304 ; _new_binds <- fixC (\ new_binds -> do
305 { addBindsC new_binds
306 ; mapFCs ( \ (b,e) -> cgTopRhs b e ) pairs' })
309 mkSRT :: DynFlags -> [Id] -> (Id,[Id]) -> Code
310 mkSRT dflags these (id,[]) = nopC
311 mkSRT dflags these (id,ids)
312 = do { ids <- mapFCs remap ids
314 ; emitRODataLits (mkSRTLabel (idName id))
315 (map (CmmLabel . mkClosureLabel dflags . idName) ids)
318 -- Sigh, better map all the ids against the environment in
319 -- case they've been externalised (see maybeExternaliseId below).
320 remap id = case filter (==id) these of
321 (id':_) -> returnFC id'
322 [] -> do { info <- getCgIdInfo id; return (cgIdInfoId info) }
324 -- Urgh! I tried moving the forkStatics call from the rhss of cgTopRhs
325 -- to enclose the listFCs in cgTopBinding, but that tickled the
326 -- statics "error" call in initC. I DON'T UNDERSTAND WHY!
328 cgTopRhs :: Id -> StgRhs -> FCode (Id, CgIdInfo)
329 -- The Id is passed along for setting up a binding...
330 -- It's already been externalised if necessary
332 cgTopRhs bndr (StgRhsCon cc con args)
333 = forkStatics (cgTopRhsCon bndr con args)
335 cgTopRhs bndr (StgRhsClosure cc bi fvs upd_flag srt args body)
336 = ASSERT(null fvs) -- There should be no free variables
337 setSRTLabel (mkSRTLabel (idName bndr)) $
338 forkStatics (cgTopRhsClosure bndr cc bi srt upd_flag args body)
342 %************************************************************************
344 \subsection{Stuff to support splitting}
346 %************************************************************************
348 If we're splitting the object, we need to externalise all the top-level names
349 (and then make sure we only use the externalised one in any C label we use
350 which refers to this name).
353 maybeExternaliseId :: DynFlags -> Id -> FCode Id
354 maybeExternaliseId dflags id
355 | dopt Opt_SplitObjs dflags, -- Externalise the name for -split-objs
356 isInternalName name = do { mod <- moduleName
357 ; returnFC (setIdName id (externalise mod)) }
358 | otherwise = returnFC id
360 externalise mod = mkExternalName uniq mod new_occ Nothing loc
362 uniq = nameUnique name
363 new_occ = mkLocalOcc uniq (nameOccName name)
364 loc = nameSrcLoc name
365 -- We want to conjure up a name that can't clash with any
366 -- existing name. So we generate
368 -- where 243 is the unique.