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 os kind _
298
= if kind == DataReference
299
-- ELF PPC64 (powerpc64-linux), AIX, MacOS 9, BeOS/PPC
300
then AccessViaSymbolPtr
301
-- actually, .label instead of label
304
howToAccessLabel _ _ os _ _
305
-- no PIC -> the dynamic linker does everything for us;
306
-- if we don't dynamically link to Haskell code,
307
-- it actually manages to do so without messing thins up.
309
, not opt_PIC && opt_Static
312
howToAccessLabel dflags arch os DataReference lbl
315
-- A dynamic label needs to be accessed via a symbol pointer.
316
_ | labelDynamic (thisPackage dflags) lbl
317
-> AccessViaSymbolPtr
319
-- For PowerPC32 -fPIC, we have to access even static data
320
-- via a symbol pointer (see below for an explanation why
321
-- PowerPC32 Linux is especially broken).
324
-> AccessViaSymbolPtr
330
-- In most cases, we have to avoid symbol stubs on ELF, for the following reasons:
331
-- on i386, the position-independent symbol stubs in the Procedure Linkage Table
332
-- require the address of the GOT to be loaded into register %ebx on entry.
333
-- The linker will take any reference to the symbol stub as a hint that
334
-- the label in question is a code label. When linking executables, this
335
-- will cause the linker to replace even data references to the label with
336
-- references to the symbol stub.
338
-- This leaves calling a (foreign) function from non-PIC code
339
-- (AccessDirectly, because we get an implicit symbol stub)
340
-- and calling functions from PIC code on non-i386 platforms (via a symbol stub)
342
howToAccessLabel dflags arch os CallReference lbl
344
, labelDynamic (thisPackage dflags) lbl && not opt_PIC
349
, labelDynamic (thisPackage dflags) lbl && opt_PIC
352
howToAccessLabel dflags _ os _ lbl
354
= if labelDynamic (thisPackage dflags) lbl
355
then AccessViaSymbolPtr
358
-- all other platforms
359
howToAccessLabel _ _ _ _ _
364
= panic "howToAccessLabel: PIC not defined for this platform"
368
-- -------------------------------------------------------------------
369
-- | Says what we we have to add to our 'PIC base register' in order to
370
-- get the address of a label.
372
picRelative :: Arch -> OS -> CLabel -> CmmLit
374
-- Darwin, but not x86_64:
375
-- The PIC base register points to the PIC base label at the beginning
376
-- of the current CmmTop. We just have to use a label difference to
378
-- We have already made sure that all labels that are not from the current
379
-- module are accessed indirectly ('as' can't calculate differences between
380
-- undefined labels).
381
picRelative arch OSDarwin lbl
383
= CmmLabelDiffOff lbl mkPicBaseLabel 0
387
-- The PIC base register points to our fake GOT. Use a label difference
388
-- to get the offset.
389
-- We have made sure that *everything* is accessed indirectly, so this
390
-- is only used for offsets from the GOT to symbol pointers inside the
392
picRelative ArchPPC os lbl
394
= CmmLabelDiffOff lbl gotLabel 0
397
-- Most Linux versions:
398
-- The PIC base register points to the GOT. Use foo@got for symbol
399
-- pointers, and foo@gotoff for everything else.
400
-- Linux and Darwin on x86_64:
401
-- The PIC base register is %rip, we use foo@gotpcrel for symbol pointers,
402
-- and a GotSymbolOffset label for other things.
403
-- For reasons of tradition, the symbol offset label is written as a plain label.
404
picRelative arch os lbl
405
| osElfTarget os || (os == OSDarwin && arch == ArchX86_64)
407
| Just (SymbolPtr, lbl') <- dynamicLinkerLabelInfo lbl
408
= CmmLabel $ mkDynamicLinkerLabel GotSymbolPtr lbl'
411
= CmmLabel $ mkDynamicLinkerLabel GotSymbolOffset lbl
416
= panic "PositionIndependentCode.picRelative undefined for this platform"
420
--------------------------------------------------------------------------------
422
-- utility function for pretty-printing asm-labels,
423
-- copied from PprMach
425
asmSDoc :: Outputable.SDoc -> Doc
427
= Outputable.withPprStyleDoc
428
(Outputable.mkCodeStyle Outputable.AsmStyle) d
430
pprCLabel_asm :: CLabel -> Doc
432
= asmSDoc (pprCLabel l)
435
needImportedSymbols :: Arch -> OS -> Bool
436
needImportedSymbols arch os
441
-- PowerPC Linux: -fPIC or -dynamic
444
= opt_PIC || not opt_Static
446
-- i386 (and others?): -dynamic but not -fPIC
449
= not opt_Static && not opt_PIC
455
-- The label used to refer to our "fake GOT" from
456
-- position-independent code.
459
-- HACK: this label isn't really foreign
462
Nothing ForeignLabelInThisPackage IsData
466
--------------------------------------------------------------------------------
467
-- We don't need to declare any offset tables.
468
-- However, for PIC on x86, we need a small helper function.
469
pprGotDeclaration :: Arch -> OS -> Doc
470
pprGotDeclaration ArchX86 OSDarwin
473
ptext (sLit ".section __TEXT,__textcoal_nt,coalesced,no_toc"),
474
ptext (sLit ".weak_definition ___i686.get_pc_thunk.ax"),
475
ptext (sLit ".private_extern ___i686.get_pc_thunk.ax"),
476
ptext (sLit "___i686.get_pc_thunk.ax:"),
477
ptext (sLit "\tmovl (%esp), %eax"),
478
ptext (sLit "\tret") ]
480
pprGotDeclaration _ OSDarwin
484
-- Output whatever needs to be output once per .s file.
485
-- The .LCTOC1 label is defined to point 32768 bytes into the table,
486
-- to make the most of the PPC's 16-bit displacements.
487
-- Only needed for PIC.
488
pprGotDeclaration arch os
497
ptext (sLit ".section \".got2\",\"aw\""),
498
ptext (sLit ".LCTOC1 = .+32768") ]
500
pprGotDeclaration _ _
501
= panic "pprGotDeclaration: no match"
504
--------------------------------------------------------------------------------
505
-- On Darwin, we have to generate our own stub code for lazy binding..
506
-- For each processor architecture, there are two versions, one for PIC
507
-- and one for non-PIC.
509
-- Whenever you change something in this assembler output, make sure
510
-- the splitter in driver/split/ghc-split.lprl recognizes the new output
512
pprImportedSymbol :: Arch -> OS -> CLabel -> Doc
513
pprImportedSymbol ArchPPC OSDarwin importedLbl
514
| Just (CodeStub, lbl) <- dynamicLinkerLabelInfo importedLbl
518
ptext (sLit ".symbol_stub"),
519
ptext (sLit "L") <> pprCLabel_asm lbl <> ptext (sLit "$stub:"),
520
ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
521
ptext (sLit "\tlis r11,ha16(L") <> pprCLabel_asm lbl
522
<> ptext (sLit "$lazy_ptr)"),
523
ptext (sLit "\tlwz r12,lo16(L") <> pprCLabel_asm lbl
524
<> ptext (sLit "$lazy_ptr)(r11)"),
525
ptext (sLit "\tmtctr r12"),
526
ptext (sLit "\taddi r11,r11,lo16(L") <> pprCLabel_asm lbl
527
<> ptext (sLit "$lazy_ptr)"),
528
ptext (sLit "\tbctr")
532
ptext (sLit ".section __TEXT,__picsymbolstub1,")
533
<> ptext (sLit "symbol_stubs,pure_instructions,32"),
534
ptext (sLit "\t.align 2"),
535
ptext (sLit "L") <> pprCLabel_asm lbl <> ptext (sLit "$stub:"),
536
ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
537
ptext (sLit "\tmflr r0"),
538
ptext (sLit "\tbcl 20,31,L0$") <> pprCLabel_asm lbl,
539
ptext (sLit "L0$") <> pprCLabel_asm lbl <> char ':',
540
ptext (sLit "\tmflr r11"),
541
ptext (sLit "\taddis r11,r11,ha16(L") <> pprCLabel_asm lbl
542
<> ptext (sLit "$lazy_ptr-L0$") <> pprCLabel_asm lbl <> char ')',
543
ptext (sLit "\tmtlr r0"),
544
ptext (sLit "\tlwzu r12,lo16(L") <> pprCLabel_asm lbl
545
<> ptext (sLit "$lazy_ptr-L0$") <> pprCLabel_asm lbl
546
<> ptext (sLit ")(r11)"),
547
ptext (sLit "\tmtctr r12"),
548
ptext (sLit "\tbctr")
551
ptext (sLit ".lazy_symbol_pointer"),
552
ptext (sLit "L") <> pprCLabel_asm lbl <> ptext (sLit "$lazy_ptr:"),
553
ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
554
ptext (sLit "\t.long dyld_stub_binding_helper")]
556
| Just (SymbolPtr, lbl) <- dynamicLinkerLabelInfo importedLbl
558
ptext (sLit ".non_lazy_symbol_pointer"),
559
char 'L' <> pprCLabel_asm lbl <> ptext (sLit "$non_lazy_ptr:"),
560
ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
561
ptext (sLit "\t.long\t0")]
567
pprImportedSymbol ArchX86 OSDarwin importedLbl
568
| Just (CodeStub, lbl) <- dynamicLinkerLabelInfo importedLbl
572
ptext (sLit ".symbol_stub"),
573
ptext (sLit "L") <> pprCLabel_asm lbl <> ptext (sLit "$stub:"),
574
ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
575
ptext (sLit "\tjmp *L") <> pprCLabel_asm lbl
576
<> ptext (sLit "$lazy_ptr"),
577
ptext (sLit "L") <> pprCLabel_asm lbl
578
<> ptext (sLit "$stub_binder:"),
579
ptext (sLit "\tpushl $L") <> pprCLabel_asm lbl
580
<> ptext (sLit "$lazy_ptr"),
581
ptext (sLit "\tjmp dyld_stub_binding_helper")
585
ptext (sLit ".section __TEXT,__picsymbolstub2,")
586
<> ptext (sLit "symbol_stubs,pure_instructions,25"),
587
ptext (sLit "L") <> pprCLabel_asm lbl <> ptext (sLit "$stub:"),
588
ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
589
ptext (sLit "\tcall ___i686.get_pc_thunk.ax"),
591
ptext (sLit "\tmovl L") <> pprCLabel_asm lbl
592
<> ptext (sLit "$lazy_ptr-1b(%eax),%edx"),
593
ptext (sLit "\tjmp *%edx"),
594
ptext (sLit "L") <> pprCLabel_asm lbl
595
<> ptext (sLit "$stub_binder:"),
596
ptext (sLit "\tlea L") <> pprCLabel_asm lbl
597
<> ptext (sLit "$lazy_ptr-1b(%eax),%eax"),
598
ptext (sLit "\tpushl %eax"),
599
ptext (sLit "\tjmp dyld_stub_binding_helper")
601
$+$ vcat [ ptext (sLit ".section __DATA, __la_sym_ptr")
602
<> (if opt_PIC then int 2 else int 3)
603
<> ptext (sLit ",lazy_symbol_pointers"),
604
ptext (sLit "L") <> pprCLabel_asm lbl <> ptext (sLit "$lazy_ptr:"),
605
ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
606
ptext (sLit "\t.long L") <> pprCLabel_asm lbl
607
<> ptext (sLit "$stub_binder")]
609
| Just (SymbolPtr, lbl) <- dynamicLinkerLabelInfo importedLbl
611
ptext (sLit ".non_lazy_symbol_pointer"),
612
char 'L' <> pprCLabel_asm lbl <> ptext (sLit "$non_lazy_ptr:"),
613
ptext (sLit "\t.indirect_symbol") <+> pprCLabel_asm lbl,
614
ptext (sLit "\t.long\t0")]
620
pprImportedSymbol _ OSDarwin _
626
-- In theory, we don't need to generate any stubs or symbol pointers
627
-- by hand for Linux.
629
-- Reality differs from this in two areas.
631
-- 1) If we just use a dynamically imported symbol directly in a read-only
632
-- section of the main executable (as GCC does), ld generates R_*_COPY
633
-- relocations, which are fundamentally incompatible with reversed info
634
-- tables. Therefore, we need a table of imported addresses in a writable
636
-- The "official" GOT mechanism (label@got) isn't intended to be used
637
-- in position dependent code, so we have to create our own "fake GOT"
638
-- when not opt_PIC && not opt_Static.
640
-- 2) PowerPC Linux is just plain broken.
641
-- While it's theoretically possible to use GOT offsets larger
642
-- than 16 bit, the standard crt*.o files don't, which leads to
643
-- linker errors as soon as the GOT size exceeds 16 bit.
644
-- Also, the assembler doesn't support @gotoff labels.
645
-- In order to be able to use a larger GOT, we have to circumvent the
646
-- entire GOT mechanism and do it ourselves (this is also what GCC does).
649
-- When needImportedSymbols is defined,
650
-- the NCG will keep track of all DynamicLinkerLabels it uses
651
-- and output each of them using pprImportedSymbol.
653
pprImportedSymbol ArchPPC_64 os _
657
pprImportedSymbol _ os importedLbl
659
= case dynamicLinkerLabelInfo importedLbl of
660
Just (SymbolPtr, lbl)
661
-> let symbolSize = case wordWidth of
662
W32 -> sLit "\t.long"
663
W64 -> sLit "\t.quad"
664
_ -> panic "Unknown wordRep in pprImportedSymbol"
667
ptext (sLit ".section \".got2\", \"aw\""),
668
ptext (sLit ".LC_") <> pprCLabel_asm lbl <> char ':',
669
ptext symbolSize <+> pprCLabel_asm lbl ]
671
-- PLT code stubs are generated automatically by the dynamic linker.
674
pprImportedSymbol _ _ _
675
= panic "PIC.pprImportedSymbol: no match"
677
--------------------------------------------------------------------------------
678
-- Generate code to calculate the address that should be put in the
679
-- PIC base register.
680
-- This is called by MachCodeGen for every CmmProc that accessed the
681
-- PIC base register. It adds the appropriate instructions to the
682
-- top of the CmmProc.
684
-- It is assumed that the first NatCmmTop in the input list is a Proc
685
-- and the rest are CmmDatas.
687
-- Darwin is simple: just fetch the address of a local label.
688
-- The FETCHPC pseudo-instruction is expanded to multiple instructions
689
-- during pretty-printing so that we don't have to deal with the
702
-- Get a pointer to our own fake GOT, which is defined on a per-module basis.
703
-- This is exactly how GCC does it, and it's quite horrible:
704
-- We first fetch the address of a local label (mkPicBaseLabel).
705
-- Then we add a 16-bit offset to that to get the address of a .long that we
706
-- define in .text space right next to the proc. This .long literal contains
707
-- the (32-bit) offset from our local label to our global offset table
708
-- (.LCTOC1 aka gotOffLabel).
710
initializePicBase_ppc
712
-> [NatCmmTop PPC.Instr]
713
-> NatM [NatCmmTop PPC.Instr]
715
initializePicBase_ppc ArchPPC os picReg
716
(CmmProc info lab params (ListGraph blocks) : statics)
719
gotOffLabel <- getNewLabelNat
720
tmp <- getNewRegNat $ intSize wordWidth
722
gotOffset = CmmData Text [
723
CmmDataLabel gotOffLabel,
724
CmmStaticLit (CmmLabelDiffOff gotLabel
729
= PPC.ImmConstantDiff
730
(PPC.ImmCLbl gotOffLabel)
731
(PPC.ImmCLbl mkPicBaseLabel)
736
b' = BasicBlock bID (PPC.FETCHPC picReg
737
: PPC.LD PPC.archWordSize tmp
738
(PPC.AddrRegImm picReg offsetToOffset)
739
: PPC.ADD picReg picReg (PPC.RIReg tmp)
742
return (CmmProc info lab params (ListGraph (b' : tail blocks)) : gotOffset : statics)
744
initializePicBase_ppc ArchPPC OSDarwin picReg
745
(CmmProc info lab params (ListGraph blocks) : statics)
746
= return (CmmProc info lab params (ListGraph (b':tail blocks)) : statics)
748
where BasicBlock bID insns = head blocks
749
b' = BasicBlock bID (PPC.FETCHPC picReg : insns)
752
initializePicBase_ppc _ _ _ _
753
= panic "initializePicBase_ppc: not needed"
756
-- We cheat a bit here by defining a pseudo-instruction named FETCHGOT
757
-- which pretty-prints as:
760
-- addl __GLOBAL_OFFSET_TABLE__+.-1b, %picReg
763
initializePicBase_x86
765
-> [NatCmmTop X86.Instr]
766
-> NatM [NatCmmTop X86.Instr]
768
initializePicBase_x86 ArchX86 os picReg
769
(CmmProc info lab params (ListGraph blocks) : statics)
771
= return (CmmProc info lab params (ListGraph (b':tail blocks)) : statics)
772
where BasicBlock bID insns = head blocks
773
b' = BasicBlock bID (X86.FETCHGOT picReg : insns)
775
initializePicBase_x86 ArchX86 OSDarwin picReg
776
(CmmProc info lab params (ListGraph blocks) : statics)
777
= return (CmmProc info lab params (ListGraph (b':tail blocks)) : statics)
779
where BasicBlock bID insns = head blocks
780
b' = BasicBlock bID (X86.FETCHPC picReg : insns)
782
initializePicBase_x86 _ _ _ _
783
= panic "initializePicBase_x86: not needed"