2 This module handles generation of position independent code and
3 dynamic-linking related issues for the native code generator.
5 This depends both the architecture and OS, so we define it here
6 instead of in one of the architecture specific modules.
8 Things outside this module which are related to this:
11 - PIC base label (pretty printed as local label 1)
12 - DynamicLinkerLabels - several kinds:
13 CodeStub, SymbolPtr, GotSymbolPtr, GotSymbolOffset
14 - labelDynamic predicate
16 - The GlobalReg datatype has a PicBaseReg constructor
17 - The CmmLit datatype has a CmmLabelDiffOff constructor
19 - When tablesNextToCode, no absolute addresses are stored in info tables
20 any more. Instead, offsets from the info label are used.
21 - For Win32 only, SRTs might contain addresses of __imp_ symbol pointers
22 because Win32 doesn't support external references in data sections.
23 TODO: make sure this still works, it might be bitrotted
25 - The cmmToCmm pass in AsmCodeGen calls cmmMakeDynamicReference for all
27 - nativeCodeGen calls pprImportedSymbol and pprGotDeclaration to output
28 all the necessary stuff for imported symbols.
29 - The NCG monad keeps track of a list of imported symbols.
30 - MachCodeGen invokes initializePicBase to generate code to initialize
31 the PIC base register when needed.
32 - MachCodeGen calls cmmMakeDynamicReference whenever it uses a CLabel
33 that wasn't in the original Cmm code (e.g. floating point literals).
35 - The mangler converts absolure refs to relative refs in info tables
36 - Symbol pointers, stub code and PIC calculations that are generated
37 by GCC are left intact by the mangler (so far only on ppc-darwin
42 cmmMakeDynamicReference,
48 initializePicBase_ppc,
54 import qualified PPC.Instr as PPC
55 import qualified PPC.Regs as PPC
57 import qualified X86.Instr as X86
67 import CLabel ( CLabel, ForeignLabelSource(..), pprCLabel,
68 mkDynamicLinkerLabel, DynamicLinkerLabelInfo(..),
69 dynamicLinkerLabelInfo, mkPicBaseLabel,
70 labelDynamic, externallyVisibleCLabel )
72 import CLabel ( mkForeignLabel )
75 import StaticFlags ( opt_PIC, opt_Static )
79 import qualified Outputable
81 import Panic ( panic )
87 --------------------------------------------------------------------------------
88 -- It gets called by the cmmToCmm pass for every CmmLabel in the Cmm
89 -- code. It does The Right Thing(tm) to convert the CmmLabel into a
90 -- position-independent, dynamic-linking-aware reference to the thing
92 -- Note that this also has to be called from MachCodeGen in order to
93 -- access static data like floating point literals (labels that were
94 -- created after the cmmToCmm pass).
95 -- The function must run in a monad that can keep track of imported symbols
96 -- A function for recording an imported symbol must be passed in:
97 -- - addImportCmmOpt for the CmmOptM monad
98 -- - addImportNat for the NatM monad.
107 cmmMakeDynamicReference, cmmMakeDynamicReference'
108 :: Monad m => DynFlags
109 -> (CLabel -> m ()) -- a monad & a function
110 -- used for recording imported symbols
111 -> ReferenceKind -- whether this is the target of a jump
112 -> CLabel -- the label
115 cmmMakeDynamicReference = cmmMakeDynamicReference'
117 cmmMakeDynamicReference' dflags addImport referenceKind lbl
118 | Just _ <- dynamicLinkerLabelInfo lbl
119 = return $ CmmLit $ CmmLabel lbl -- already processed it, pass through
122 = case howToAccessLabel
124 (platformArch $ targetPlatform dflags)
125 (platformOS $ targetPlatform dflags)
129 let stub = mkDynamicLinkerLabel CodeStub lbl
131 return $ CmmLit $ CmmLabel stub
133 AccessViaSymbolPtr -> do
134 let symbolPtr = mkDynamicLinkerLabel SymbolPtr lbl
136 return $ CmmLoad (cmmMakePicReference dflags symbolPtr) bWord
138 AccessDirectly -> case referenceKind of
139 -- for data, we might have to make some calculations:
140 DataReference -> return $ cmmMakePicReference dflags lbl
141 -- all currently supported processors support
142 -- PC-relative branch and call instructions,
143 -- so just jump there if it's a call or a jump
144 _ -> return $ CmmLit $ CmmLabel lbl
147 -- -----------------------------------------------------------------------------
148 -- Create a position independent reference to a label.
149 -- (but do not bother with dynamic linking).
150 -- We calculate the label's address by adding some (platform-dependent)
151 -- offset to our base register; this offset is calculated by
152 -- the function picRelative in the platform-dependent part below.
154 cmmMakePicReference :: DynFlags -> CLabel -> CmmExpr
155 cmmMakePicReference dflags lbl
157 -- Windows doesn't need PIC,
158 -- everything gets relocated at runtime
159 | OSMinGW32 <- platformOS $ targetPlatform dflags
160 = CmmLit $ CmmLabel lbl
163 | (opt_PIC || not opt_Static) && absoluteLabel lbl
164 = CmmMachOp (MO_Add wordWidth)
165 [ CmmReg (CmmGlobal PicBaseReg)
166 , CmmLit $ picRelative
167 (platformArch $ targetPlatform dflags)
168 (platformOS $ targetPlatform dflags)
172 = CmmLit $ CmmLabel lbl
175 absoluteLabel :: CLabel -> Bool
177 = case dynamicLinkerLabelInfo lbl of
178 Just (GotSymbolPtr, _) -> False
179 Just (GotSymbolOffset, _) -> False
183 --------------------------------------------------------------------------------
184 -- Knowledge about how special dynamic linker labels like symbol
185 -- pointers, code stubs and GOT offsets look like is located in the
188 -- We have to decide which labels need to be accessed
189 -- indirectly or via a piece of stub code.
190 data LabelAccessStyle
196 :: DynFlags -> Arch -> OS -> ReferenceKind -> CLabel -> LabelAccessStyle
200 -- In Windows speak, a "module" is a set of objects linked into the
201 -- same Portable Exectuable (PE) file. (both .exe and .dll files are PEs).
203 -- If we're compiling a multi-module program then symbols from other modules
204 -- are accessed by a symbol pointer named __imp_SYMBOL. At runtime we have the
207 -- (in the local module)
208 -- __imp_SYMBOL: addr of SYMBOL
210 -- (in the other module)
211 -- SYMBOL: the real function / data.
213 -- To access the function at SYMBOL from our local module, we just need to
214 -- dereference the local __imp_SYMBOL.
216 -- If opt_Static is set then we assume that all our code will be linked
217 -- into the same .exe file. In this case we always access symbols directly,
218 -- and never use __imp_SYMBOL.
220 howToAccessLabel dflags _ OSMinGW32 _ lbl
222 -- Assume all symbols will be in the same PE, so just access them directly.
226 -- If the target symbol is in another PE we need to access it via the
227 -- appropriate __imp_SYMBOL pointer.
228 | labelDynamic (thisPackage dflags) lbl
231 -- Target symbol is in the same PE as the caller, so just access it directly.
236 -- Mach-O (Darwin, Mac OS X)
238 -- Indirect access is required in the following cases:
239 -- * things imported from a dynamic library
240 -- * (not on x86_64) data from a different module, if we're generating PIC code
241 -- It is always possible to access something indirectly,
242 -- even when it's not necessary.
244 howToAccessLabel dflags arch OSDarwin DataReference lbl
245 -- data access to a dynamic library goes via a symbol pointer
246 | labelDynamic (thisPackage dflags) lbl
249 -- when generating PIC code, all cross-module data references must
250 -- must go via a symbol pointer, too, because the assembler
251 -- cannot generate code for a label difference where one
252 -- label is undefined. Doesn't apply t x86_64.
253 -- Unfortunately, we don't know whether it's cross-module,
254 -- so we do it for all externally visible labels.
255 -- This is a slight waste of time and space, but otherwise
256 -- we'd need to pass the current Module all the way in to
259 , opt_PIC && externallyVisibleCLabel lbl
265 howToAccessLabel dflags arch OSDarwin JumpReference lbl
266 -- dyld code stubs don't work for tailcalls because the
267 -- stack alignment is only right for regular calls.
268 -- Therefore, we have to go via a symbol pointer:
269 | arch == ArchX86 || arch == ArchX86_64
270 , labelDynamic (thisPackage dflags) lbl
274 howToAccessLabel dflags arch OSDarwin _ lbl
275 -- Code stubs are the usual method of choice for imported code;
276 -- not needed on x86_64 because Apple's new linker, ld64, generates
277 -- them automatically.
279 , labelDynamic (thisPackage dflags) lbl
287 -- ELF tries to pretend to the main application code that dynamic linking does
288 -- not exist. While this may sound convenient, it tends to mess things up in
289 -- very bad ways, so we have to be careful when we generate code for the main
290 -- program (-dynamic but no -fPIC).
292 -- Indirect access is required for references to imported symbols
293 -- from position independent code. It is also required from the main program
294 -- when dynamic libraries containing Haskell code are used.
296 howToAccessLabel _ ArchPPC_64 OSLinux kind _
298 -- ELF PPC64 (powerpc64-linux), AIX, MacOS 9, BeOS/PPC
299 | DataReference <- kind
302 -- actually, .label instead of label
306 howToAccessLabel _ _ OSLinux _ _
307 -- no PIC -> the dynamic linker does everything for us;
308 -- if we don't dynamically link to Haskell code,
309 -- it actually manages to do so without messing thins up.
310 | not opt_PIC && opt_Static
313 howToAccessLabel dflags arch OSLinux DataReference lbl
314 -- A dynamic label needs to be accessed via a symbol pointer.
315 | labelDynamic (thisPackage dflags) lbl
318 -- For PowerPC32 -fPIC, we have to access even static data
319 -- via a symbol pointer (see below for an explanation why
320 -- PowerPC32 Linux is especially broken).
329 -- In most cases, we have to avoid symbol stubs on ELF, for the following reasons:
330 -- on i386, the position-independent symbol stubs in the Procedure Linkage Table
331 -- require the address of the GOT to be loaded into register %ebx on entry.
332 -- The linker will take any reference to the symbol stub as a hint that
333 -- the label in question is a code label. When linking executables, this
334 -- will cause the linker to replace even data references to the label with
335 -- references to the symbol stub.
337 -- This leaves calling a (foreign) function from non-PIC code
338 -- (AccessDirectly, because we get an implicit symbol stub)
339 -- and calling functions from PIC code on non-i386 platforms (via a symbol stub)
341 howToAccessLabel dflags arch OSLinux CallReference lbl
342 | labelDynamic (thisPackage dflags) lbl && not opt_PIC
346 , labelDynamic (thisPackage dflags) lbl && opt_PIC
349 howToAccessLabel dflags _ OSLinux _ lbl
350 | labelDynamic (thisPackage dflags) lbl
356 -- all other platforms
357 howToAccessLabel _ _ _ _ _
362 = panic "howToAccessLabel: PIC not defined for this platform"
366 -- -------------------------------------------------------------------
367 -- | Says what we we have to add to our 'PIC base register' in order to
368 -- get the address of a label.
370 picRelative :: Arch -> OS -> CLabel -> CmmLit
372 -- Darwin, but not x86_64:
373 -- The PIC base register points to the PIC base label at the beginning
374 -- of the current CmmTop. We just have to use a label difference to
376 -- We have already made sure that all labels that are not from the current
377 -- module are accessed indirectly ('as' can't calculate differences between
378 -- undefined labels).
379 picRelative arch OSDarwin lbl
381 = CmmLabelDiffOff lbl mkPicBaseLabel 0
385 -- The PIC base register points to our fake GOT. Use a label difference
386 -- to get the offset.
387 -- We have made sure that *everything* is accessed indirectly, so this
388 -- is only used for offsets from the GOT to symbol pointers inside the
390 picRelative ArchPPC OSLinux lbl
391 = CmmLabelDiffOff lbl gotLabel 0
394 -- Most Linux versions:
395 -- The PIC base register points to the GOT. Use foo@got for symbol
396 -- pointers, and foo@gotoff for everything else.
397 -- Linux and Darwin on x86_64:
398 -- The PIC base register is %rip, we use foo@gotpcrel for symbol pointers,
399 -- and a GotSymbolOffset label for other things.
400 -- For reasons of tradition, the symbol offset label is written as a plain label.
401 picRelative arch os lbl
402 | os == OSLinux || (os == OSDarwin && arch == ArchX86_64)
404 | Just (SymbolPtr, lbl') <- dynamicLinkerLabelInfo lbl
405 = CmmLabel $ mkDynamicLinkerLabel GotSymbolPtr lbl'
408 = CmmLabel $ mkDynamicLinkerLabel GotSymbolOffset lbl
413 = panic "PositionIndependentCode.picRelative undefined for this platform"
417 --------------------------------------------------------------------------------
419 -- utility function for pretty-printing asm-labels,
420 -- copied from PprMach
422 asmSDoc :: Outputable.SDoc -> Doc
424 = Outputable.withPprStyleDoc
425 (Outputable.mkCodeStyle Outputable.AsmStyle) d
427 pprCLabel_asm :: CLabel -> Doc
429 = asmSDoc (pprCLabel l)
432 needImportedSymbols :: Arch -> OS -> Bool
433 needImportedSymbols arch os
438 -- PowerPC Linux: -fPIC or -dynamic
441 = opt_PIC || not opt_Static
443 -- i386 (and others?): -dynamic but not -fPIC
446 = not opt_Static && not opt_PIC
452 -- The label used to refer to our "fake GOT" from
453 -- position-independent code.
456 -- HACK: this label isn't really foreign
459 Nothing ForeignLabelInThisPackage IsData
463 --------------------------------------------------------------------------------
464 -- We don't need to declare any offset tables.
465 -- However, for PIC on x86, we need a small helper function.
466 pprGotDeclaration :: Arch -> OS -> Doc
467 pprGotDeclaration ArchX86 OSDarwin
470 ptext (sLit ".section __TEXT,__textcoal_nt,coalesced,no_toc"),
471 ptext (sLit ".weak_definition ___i686.get_pc_thunk.ax"),
472 ptext (sLit ".private_extern ___i686.get_pc_thunk.ax"),
473 ptext (sLit "___i686.get_pc_thunk.ax:"),
474 ptext (sLit "\tmovl (%esp), %eax"),
475 ptext (sLit "\tret") ]
477 pprGotDeclaration _ OSDarwin
481 -- Output whatever needs to be output once per .s file.
482 -- The .LCTOC1 label is defined to point 32768 bytes into the table,
483 -- to make the most of the PPC's 16-bit displacements.
484 -- Only needed for PIC.
485 pprGotDeclaration arch OSLinux
492 ptext (sLit ".section \".got2\",\"aw\""),
493 ptext (sLit ".LCTOC1 = .+32768") ]
495 pprGotDeclaration _ _
496 = panic "pprGotDeclaration: no match"
499 --------------------------------------------------------------------------------
500 -- On Darwin, we have to generate our own stub code for lazy binding..
501 -- For each processor architecture, there are two versions, one for PIC
502 -- and one for non-PIC.
504 -- Whenever you change something in this assembler output, make sure
505 -- the splitter in driver/split/ghc-split.lprl recognizes the new output
507 pprImportedSymbol :: Arch -> OS -> CLabel -> Doc
508 pprImportedSymbol ArchPPC OSDarwin importedLbl
509 | Just (CodeStub, lbl) <- dynamicLinkerLabelInfo importedLbl
513 ptext (sLit ".symbol_stub"),
514 ptext (sLit "L") <> pprCLabel_asm lbl <> ptext (sLit "$stub:"),
515 ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
516 ptext (sLit "\tlis r11,ha16(L") <> pprCLabel_asm lbl
517 <> ptext (sLit "$lazy_ptr)"),
518 ptext (sLit "\tlwz r12,lo16(L") <> pprCLabel_asm lbl
519 <> ptext (sLit "$lazy_ptr)(r11)"),
520 ptext (sLit "\tmtctr r12"),
521 ptext (sLit "\taddi r11,r11,lo16(L") <> pprCLabel_asm lbl
522 <> ptext (sLit "$lazy_ptr)"),
523 ptext (sLit "\tbctr")
527 ptext (sLit ".section __TEXT,__picsymbolstub1,")
528 <> ptext (sLit "symbol_stubs,pure_instructions,32"),
529 ptext (sLit "\t.align 2"),
530 ptext (sLit "L") <> pprCLabel_asm lbl <> ptext (sLit "$stub:"),
531 ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
532 ptext (sLit "\tmflr r0"),
533 ptext (sLit "\tbcl 20,31,L0$") <> pprCLabel_asm lbl,
534 ptext (sLit "L0$") <> pprCLabel_asm lbl <> char ':',
535 ptext (sLit "\tmflr r11"),
536 ptext (sLit "\taddis r11,r11,ha16(L") <> pprCLabel_asm lbl
537 <> ptext (sLit "$lazy_ptr-L0$") <> pprCLabel_asm lbl <> char ')',
538 ptext (sLit "\tmtlr r0"),
539 ptext (sLit "\tlwzu r12,lo16(L") <> pprCLabel_asm lbl
540 <> ptext (sLit "$lazy_ptr-L0$") <> pprCLabel_asm lbl
541 <> ptext (sLit ")(r11)"),
542 ptext (sLit "\tmtctr r12"),
543 ptext (sLit "\tbctr")
546 ptext (sLit ".lazy_symbol_pointer"),
547 ptext (sLit "L") <> pprCLabel_asm lbl <> ptext (sLit "$lazy_ptr:"),
548 ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
549 ptext (sLit "\t.long dyld_stub_binding_helper")]
551 | Just (SymbolPtr, lbl) <- dynamicLinkerLabelInfo importedLbl
553 ptext (sLit ".non_lazy_symbol_pointer"),
554 char 'L' <> pprCLabel_asm lbl <> ptext (sLit "$non_lazy_ptr:"),
555 ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
556 ptext (sLit "\t.long\t0")]
562 pprImportedSymbol ArchX86 OSDarwin importedLbl
563 | Just (CodeStub, lbl) <- dynamicLinkerLabelInfo importedLbl
567 ptext (sLit ".symbol_stub"),
568 ptext (sLit "L") <> pprCLabel_asm lbl <> ptext (sLit "$stub:"),
569 ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
570 ptext (sLit "\tjmp *L") <> pprCLabel_asm lbl
571 <> ptext (sLit "$lazy_ptr"),
572 ptext (sLit "L") <> pprCLabel_asm lbl
573 <> ptext (sLit "$stub_binder:"),
574 ptext (sLit "\tpushl $L") <> pprCLabel_asm lbl
575 <> ptext (sLit "$lazy_ptr"),
576 ptext (sLit "\tjmp dyld_stub_binding_helper")
580 ptext (sLit ".section __TEXT,__picsymbolstub2,")
581 <> ptext (sLit "symbol_stubs,pure_instructions,25"),
582 ptext (sLit "L") <> pprCLabel_asm lbl <> ptext (sLit "$stub:"),
583 ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
584 ptext (sLit "\tcall ___i686.get_pc_thunk.ax"),
586 ptext (sLit "\tmovl L") <> pprCLabel_asm lbl
587 <> ptext (sLit "$lazy_ptr-1b(%eax),%edx"),
588 ptext (sLit "\tjmp *%edx"),
589 ptext (sLit "L") <> pprCLabel_asm lbl
590 <> ptext (sLit "$stub_binder:"),
591 ptext (sLit "\tlea L") <> pprCLabel_asm lbl
592 <> ptext (sLit "$lazy_ptr-1b(%eax),%eax"),
593 ptext (sLit "\tpushl %eax"),
594 ptext (sLit "\tjmp dyld_stub_binding_helper")
596 $+$ vcat [ ptext (sLit ".section __DATA, __la_sym_ptr")
597 <> (if opt_PIC then int 2 else int 3)
598 <> ptext (sLit ",lazy_symbol_pointers"),
599 ptext (sLit "L") <> pprCLabel_asm lbl <> ptext (sLit "$lazy_ptr:"),
600 ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
601 ptext (sLit "\t.long L") <> pprCLabel_asm lbl
602 <> ptext (sLit "$stub_binder")]
604 | Just (SymbolPtr, lbl) <- dynamicLinkerLabelInfo importedLbl
606 ptext (sLit ".non_lazy_symbol_pointer"),
607 char 'L' <> pprCLabel_asm lbl <> ptext (sLit "$non_lazy_ptr:"),
608 ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
609 ptext (sLit "\t.long\t0")]
615 pprImportedSymbol _ OSDarwin _
621 -- In theory, we don't need to generate any stubs or symbol pointers
622 -- by hand for Linux.
624 -- Reality differs from this in two areas.
626 -- 1) If we just use a dynamically imported symbol directly in a read-only
627 -- section of the main executable (as GCC does), ld generates R_*_COPY
628 -- relocations, which are fundamentally incompatible with reversed info
629 -- tables. Therefore, we need a table of imported addresses in a writable
631 -- The "official" GOT mechanism (label@got) isn't intended to be used
632 -- in position dependent code, so we have to create our own "fake GOT"
633 -- when not opt_PCI && not opt_Static.
635 -- 2) PowerPC Linux is just plain broken.
636 -- While it's theoretically possible to use GOT offsets larger
637 -- than 16 bit, the standard crt*.o files don't, which leads to
638 -- linker errors as soon as the GOT size exceeds 16 bit.
639 -- Also, the assembler doesn't support @gotoff labels.
640 -- In order to be able to use a larger GOT, we have to circumvent the
641 -- entire GOT mechanism and do it ourselves (this is also what GCC does).
644 -- When needImportedSymbols is defined,
645 -- the NCG will keep track of all DynamicLinkerLabels it uses
646 -- and output each of them using pprImportedSymbol.
648 pprImportedSymbol ArchPPC_64 OSLinux _
651 pprImportedSymbol _ OSLinux importedLbl
652 | Just (SymbolPtr, lbl) <- dynamicLinkerLabelInfo importedLbl
653 = let symbolSize = case wordWidth of
654 W32 -> sLit "\t.long"
655 W64 -> sLit "\t.quad"
656 _ -> panic "Unknown wordRep in pprImportedSymbol"
659 ptext (sLit ".section \".got2\", \"aw\""),
660 ptext (sLit ".LC_") <> pprCLabel_asm lbl <> char ':',
661 ptext symbolSize <+> pprCLabel_asm lbl ]
663 -- PLT code stubs are generated automatically by the dynamic linker.
666 pprImportedSymbol _ _ _
667 = panic "PIC.pprImportedSymbol: no match"
669 --------------------------------------------------------------------------------
670 -- Generate code to calculate the address that should be put in the
671 -- PIC base register.
672 -- This is called by MachCodeGen for every CmmProc that accessed the
673 -- PIC base register. It adds the appropriate instructions to the
674 -- top of the CmmProc.
676 -- It is assumed that the first NatCmmTop in the input list is a Proc
677 -- and the rest are CmmDatas.
679 -- Darwin is simple: just fetch the address of a local label.
680 -- The FETCHPC pseudo-instruction is expanded to multiple instructions
681 -- during pretty-printing so that we don't have to deal with the
694 -- Get a pointer to our own fake GOT, which is defined on a per-module basis.
695 -- This is exactly how GCC does it, and it's quite horrible:
696 -- We first fetch the address of a local label (mkPicBaseLabel).
697 -- Then we add a 16-bit offset to that to get the address of a .long that we
698 -- define in .text space right next to the proc. This .long literal contains
699 -- the (32-bit) offset from our local label to our global offset table
700 -- (.LCTOC1 aka gotOffLabel).
702 initializePicBase_ppc
704 -> [NatCmmTop PPC.Instr]
705 -> NatM [NatCmmTop PPC.Instr]
707 initializePicBase_ppc ArchPPC OSLinux picReg
708 (CmmProc info lab params (ListGraph blocks) : statics)
710 gotOffLabel <- getNewLabelNat
711 tmp <- getNewRegNat $ intSize wordWidth
713 gotOffset = CmmData Text [
714 CmmDataLabel gotOffLabel,
715 CmmStaticLit (CmmLabelDiffOff gotLabel
720 = PPC.ImmConstantDiff
721 (PPC.ImmCLbl gotOffLabel)
722 (PPC.ImmCLbl mkPicBaseLabel)
727 b' = BasicBlock bID (PPC.FETCHPC picReg
728 : PPC.LD PPC.archWordSize tmp
729 (PPC.AddrRegImm picReg offsetToOffset)
730 : PPC.ADD picReg picReg (PPC.RIReg tmp)
733 return (CmmProc info lab params (ListGraph (b' : tail blocks)) : gotOffset : statics)
735 initializePicBase_ppc ArchPPC OSDarwin picReg
736 (CmmProc info lab params (ListGraph blocks) : statics)
737 = return (CmmProc info lab params (ListGraph (b':tail blocks)) : statics)
739 where BasicBlock bID insns = head blocks
740 b' = BasicBlock bID (PPC.FETCHPC picReg : insns)
743 initializePicBase_ppc _ _ _ _
744 = panic "initializePicBase_ppc: not needed"
747 -- We cheat a bit here by defining a pseudo-instruction named FETCHGOT
748 -- which pretty-prints as:
751 -- addl __GLOBAL_OFFSET_TABLE__+.-1b, %picReg
754 initializePicBase_x86
756 -> [NatCmmTop X86.Instr]
757 -> NatM [NatCmmTop X86.Instr]
759 initializePicBase_x86 ArchX86 OSLinux picReg
760 (CmmProc info lab params (ListGraph blocks) : statics)
761 = return (CmmProc info lab params (ListGraph (b':tail blocks)) : statics)
762 where BasicBlock bID insns = head blocks
763 b' = BasicBlock bID (X86.FETCHGOT picReg : insns)
765 initializePicBase_x86 ArchX86 OSDarwin picReg
766 (CmmProc info lab params (ListGraph blocks) : statics)
767 = return (CmmProc info lab params (ListGraph (b':tail blocks)) : statics)
769 where BasicBlock bID insns = head blocks
770 b' = BasicBlock bID (X86.FETCHPC picReg : insns)
772 initializePicBase_x86 _ _ _ _
773 = panic "initializePicBase_x86: not needed"