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 ( TyCon )
51 import Module ( Module, mkModule )
52 import ErrUtils ( dumpIfSet_dyn, showPass )
53 import Panic ( assertPanic )
65 -> [Module] -- directly-imported modules
66 -> CollectedCCs -- (Local/global) cost-centres needing declaring/registering.
67 -> [(StgBinding,[(Id,[Id])])] -- Bindings to convert, with SRTs
70 codeGen dflags this_mod data_tycons foreign_stubs imported_mods
71 cost_centre_info stg_binds
73 { showPass dflags "CodeGen"
74 ; let way = buildTag dflags
75 mb_main_mod = mainModIs dflags
78 -- ; mapM_ (\x -> seq x (return ())) data_tycons
80 ; code_stuff <- initC dflags this_mod $ do
81 { cmm_binds <- mapM (getCmm . cgTopBinding dflags) stg_binds
82 ; cmm_tycons <- mapM cgTyCon data_tycons
83 ; cmm_init <- getCmm (mkModuleInit dflags way cost_centre_info
85 foreign_stubs imported_mods)
86 ; return (cmm_binds ++ concat cmm_tycons
87 ++ if opt_SccProfilingOn
88 #if defined(mingw32_HOST_OS)
94 -- Put datatype_stuff after code_stuff, because the
95 -- datatype closure table (for enumeration types) to
96 -- (say) PrelBase_True_closure, which is defined in
99 ; dumpIfSet_dyn dflags Opt_D_dump_cmm "Cmm" (pprCmms code_stuff)
101 ; return code_stuff }
104 %************************************************************************
106 \subsection[codegen-init]{Module initialisation code}
108 %************************************************************************
110 /* -----------------------------------------------------------------------------
111 Module initialisation
113 The module initialisation code looks like this, roughly:
116 JMP_(__stginit_Foo_1_p)
119 FN(__stginit_Foo_1_p) {
123 We have one version of the init code with a module version and the
124 'way' attached to it. The version number helps to catch cases
125 where modules are not compiled in dependency order before being
126 linked: if a module has been compiled since any modules which depend on
127 it, then the latter modules will refer to a different version in their
128 init blocks and a link error will ensue.
130 The 'way' suffix helps to catch cases where modules compiled in different
131 ways are linked together (eg. profiled and non-profiled).
133 We provide a plain, unadorned, version of the module init code
134 which just jumps to the version with the label and way attached. The
135 reason for this is that when using foreign exports, the caller of
136 startupHaskell() must supply the name of the init function for the "top"
137 module in the program, and we don't want to require that this name
138 has the version and way info appended to it.
139 -------------------------------------------------------------------------- */
141 We initialise the module tree by keeping a work-stack,
143 * that grows downward
144 * Sp points to the last occupied slot
150 -> String -- the "way"
151 -> CollectedCCs -- cost centre info
153 -> Maybe String -- Just m ==> we have flag: -main-is Foo.baz
157 mkModuleInit dflags way cost_centre_info this_mod mb_main_mod foreign_stubs imported_mods
160 -- Allocate the static boolean that records if this
161 -- module has been registered already
162 ; emitData Data [CmmDataLabel moduleRegdLabel,
163 CmmStaticLit zeroCLit]
165 ; emitSimpleProc real_init_lbl $ do
166 { -- The return-code pops the work stack by
167 -- incrementing Sp, and then jumpd to the popped item
168 ret_blk <- forkLabelledCode $ stmtsC
169 [ CmmAssign spReg (cmmRegOffW spReg 1)
170 , CmmJump (CmmLoad (cmmRegOffW spReg (-1)) wordRep) [] ]
172 ; init_blk <- forkLabelledCode $ do
173 { mod_init_code; stmtC (CmmBranch ret_blk) }
175 ; stmtC (CmmCondBranch (cmmNeWord (CmmLit zeroCLit) mod_reg_val)
177 ; stmtC (CmmBranch init_blk)
181 -- Make the "plain" procedure jump to the "real" init procedure
182 ; emitSimpleProc plain_init_lbl jump_to_init
184 -- When compiling the module in which the 'main' function lives,
185 -- (that is, this_mod == main_mod)
186 -- we inject an extra stg_init procedure for stg_init_ZCMain, for the
187 -- RTS to invoke. We must consult the -main-is flag in case the
188 -- user specified a different function to Main.main
189 ; whenC (this_mod == main_mod)
190 (emitSimpleProc plain_main_init_lbl jump_to_init)
193 plain_init_lbl = mkPlainModuleInitLabel dflags this_mod
194 real_init_lbl = mkModuleInitLabel dflags this_mod way
195 plain_main_init_lbl = mkPlainModuleInitLabel dflags rOOT_MAIN
197 jump_to_init = stmtC (CmmJump (mkLblExpr real_init_lbl) [])
199 mod_reg_val = CmmLoad (mkLblExpr moduleRegdLabel) wordRep
201 main_mod = case mb_main_mod of
202 Just mod_name -> mkModule mod_name
205 -- Main refers to GHC.TopHandler.runIO, so make sure we call the
206 -- init function for GHC.TopHandler.
208 | this_mod == main_mod = [pREL_TOP_HANDLER]
212 { -- Set mod_reg to 1 to record that we've been here
213 stmtC (CmmStore (mkLblExpr moduleRegdLabel) (CmmLit (mkIntCLit 1)))
215 -- Now do local stuff
216 #if defined(mingw32_HOST_OS)
217 ; registerForeignExports foreign_stubs
219 ; initCostCentres cost_centre_info
220 ; mapCs (registerModuleImport dflags way)
221 (imported_mods++extra_imported_mods)
225 -----------------------
226 registerModuleImport :: DynFlags -> String -> Module -> Code
227 registerModuleImport dflags way mod
230 | otherwise -- Push the init procedure onto the work stack
231 = stmtsC [ CmmAssign spReg (cmmRegOffW spReg (-1))
232 , CmmStore (CmmReg spReg) (mkLblExpr (mkModuleInitLabel dflags mod way)) ]
234 -----------------------
235 registerForeignExports :: ForeignStubs -> Code
236 registerForeignExports NoStubs
238 registerForeignExports (ForeignStubs _ _ _ fe_bndrs)
239 = mapM_ mk_export_register fe_bndrs
241 mk_export_register bndr
242 = emitRtsCall SLIT("getStablePtr")
243 [ (CmmLit (CmmLabel (mkLocalClosureLabel (idName bndr))),
249 Cost-centre profiling: Besides the usual stuff, we must produce
250 declarations for the cost-centres defined in this module;
252 (The local cost-centres involved in this are passed into the
256 initCostCentres :: CollectedCCs -> Code
257 -- Emit the declarations, and return code to register them
258 initCostCentres (local_CCs, ___extern_CCs, singleton_CCSs)
259 | not opt_SccProfilingOn = nopC
261 = do { mapM_ emitCostCentreDecl local_CCs
262 ; mapM_ emitCostCentreStackDecl singleton_CCSs
263 ; mapM_ emitRegisterCC local_CCs
264 ; mapM_ emitRegisterCCS singleton_CCSs
268 %************************************************************************
270 \subsection[codegen-top-bindings]{Converting top-level STG bindings}
272 %************************************************************************
274 @cgTopBinding@ is only used for top-level bindings, since they need
275 to be allocated statically (not in the heap) and need to be labelled.
276 No unboxed bindings can happen at top level.
278 In the code below, the static bindings are accumulated in the
279 @MkCgState@, and transferred into the ``statics'' slot by @forkStatics@.
280 This is so that we can write the top level processing in a compositional
281 style, with the increasing static environment being plumbed as a state
285 cgTopBinding :: DynFlags -> (StgBinding,[(Id,[Id])]) -> Code
286 cgTopBinding dflags (StgNonRec id rhs, srts)
287 = do { id' <- maybeExternaliseId dflags id
288 ; mapM_ (mkSRT dflags [id']) srts
289 ; (id,info) <- cgTopRhs id' rhs
290 ; addBindC id info -- Add the *un-externalised* Id to the envt,
291 -- so we find it when we look up occurrences
294 cgTopBinding dflags (StgRec pairs, srts)
295 = do { let (bndrs, rhss) = unzip pairs
296 ; bndrs' <- mapFCs (maybeExternaliseId dflags) bndrs
297 ; let pairs' = zip bndrs' rhss
298 ; mapM_ (mkSRT dflags bndrs') srts
299 ; _new_binds <- fixC (\ new_binds -> do
300 { addBindsC new_binds
301 ; mapFCs ( \ (b,e) -> cgTopRhs b e ) pairs' })
304 mkSRT :: DynFlags -> [Id] -> (Id,[Id]) -> Code
305 mkSRT dflags these (id,[]) = nopC
306 mkSRT dflags these (id,ids)
307 = do { ids <- mapFCs remap ids
309 ; emitRODataLits (mkSRTLabel (idName id))
310 (map (CmmLabel . mkClosureLabel dflags . idName) ids)
313 -- Sigh, better map all the ids against the environment in
314 -- case they've been externalised (see maybeExternaliseId below).
315 remap id = case filter (==id) these of
316 (id':_) -> returnFC id'
317 [] -> do { info <- getCgIdInfo id; return (cgIdInfoId info) }
319 -- Urgh! I tried moving the forkStatics call from the rhss of cgTopRhs
320 -- to enclose the listFCs in cgTopBinding, but that tickled the
321 -- statics "error" call in initC. I DON'T UNDERSTAND WHY!
323 cgTopRhs :: Id -> StgRhs -> FCode (Id, CgIdInfo)
324 -- The Id is passed along for setting up a binding...
325 -- It's already been externalised if necessary
327 cgTopRhs bndr (StgRhsCon cc con args)
328 = forkStatics (cgTopRhsCon bndr con args)
330 cgTopRhs bndr (StgRhsClosure cc bi fvs upd_flag srt args body)
331 = ASSERT(null fvs) -- There should be no free variables
332 setSRTLabel (mkSRTLabel (idName bndr)) $
333 forkStatics (cgTopRhsClosure bndr cc bi srt upd_flag args body)
337 %************************************************************************
339 \subsection{Stuff to support splitting}
341 %************************************************************************
343 If we're splitting the object, we need to externalise all the top-level names
344 (and then make sure we only use the externalised one in any C label we use
345 which refers to this name).
348 maybeExternaliseId :: DynFlags -> Id -> FCode Id
349 maybeExternaliseId dflags id
350 | dopt Opt_SplitObjs dflags, -- Externalise the name for -split-objs
351 isInternalName name = do { mod <- moduleName
352 ; returnFC (setIdName id (externalise mod)) }
353 | otherwise = returnFC id
355 externalise mod = mkExternalName uniq mod new_occ Nothing loc
357 uniq = nameUnique name
358 new_occ = mkLocalOcc uniq (nameOccName name)
359 loc = nameSrcLoc name
360 -- We want to conjure up a name that can't clash with any
361 -- existing name. So we generate
363 -- where 243 is the unique.