1 //===-- PPCAsmPrinter.cpp - Print machine instrs to PowerPC assembly ------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains a printer that converts from our internal representation
11 // of machine-dependent LLVM code to PowerPC assembly language. This printer is
12 // the output mechanism used by `llc'.
13 //
14 // Documentation at http://developer.apple.com/documentation/DeveloperTools/
15 // Reference/Assembler/ASMIntroduction/chapter_1_section_1.html
16 //
17 //===----------------------------------------------------------------------===//
18 
19 #define DEBUG_TYPE "asmprinter"
20 #include "PPC.h"
21 #include "PPCTargetMachine.h"
22 #include "PPCSubtarget.h"
23 #include "InstPrinter/PPCInstPrinter.h"
24 #include "MCTargetDesc/PPCPredicates.h"
25 #include "llvm/Constants.h"
26 #include "llvm/DebugInfo.h"
27 #include "llvm/DerivedTypes.h"
28 #include "llvm/Module.h"
29 #include "llvm/Assembly/Writer.h"
30 #include "llvm/CodeGen/AsmPrinter.h"
31 #include "llvm/CodeGen/MachineFunctionPass.h"
32 #include "llvm/CodeGen/MachineInstr.h"
33 #include "llvm/CodeGen/MachineInstrBuilder.h"
34 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
35 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
36 #include "llvm/MC/MCAsmInfo.h"
37 #include "llvm/MC/MCContext.h"
38 #include "llvm/MC/MCExpr.h"
39 #include "llvm/MC/MCInst.h"
40 #include "llvm/MC/MCInstBuilder.h"
41 #include "llvm/MC/MCSectionMachO.h"
42 #include "llvm/MC/MCStreamer.h"
43 #include "llvm/MC/MCSymbol.h"
44 #include "llvm/MC/MCSectionELF.h"
45 #include "llvm/Target/Mangler.h"
46 #include "llvm/Target/TargetRegisterInfo.h"
47 #include "llvm/Target/TargetInstrInfo.h"
48 #include "llvm/Target/TargetOptions.h"
49 #include "llvm/Support/CommandLine.h"
50 #include "llvm/Support/Debug.h"
51 #include "llvm/Support/MathExtras.h"
52 #include "llvm/Support/ErrorHandling.h"
53 #include "llvm/Support/TargetRegistry.h"
54 #include "llvm/Support/raw_ostream.h"
55 #include "llvm/Support/ELF.h"
56 #include "llvm/ADT/StringExtras.h"
57 #include "llvm/ADT/SmallString.h"
58 #include "llvm/ADT/MapVector.h"
59 using namespace llvm;
60 
61 namespace {
62   class PPCAsmPrinter : public AsmPrinter {
63   protected:
64     MapVector<MCSymbol*, MCSymbol*> TOC;
65     const PPCSubtarget &Subtarget;
66     uint64_t TOCLabelID;
67   public:
68     explicit PPCAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
69       : AsmPrinter(TM, Streamer),
70         Subtarget(TM.getSubtarget<PPCSubtarget>()), TOCLabelID(0) {}
71 
72     virtual const char *getPassName() const {
73       return "PowerPC Assembly Printer";
74     }
75 
76     MCSymbol *lookUpOrCreateTOCEntry(MCSymbol *Sym);
77 
78     virtual void EmitInstruction(const MachineInstr *MI);
79 
80     void printOperand(const MachineInstr *MI, unsigned OpNo, raw_ostream &O);
81 
82     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
83                          unsigned AsmVariant, const char *ExtraCode,
84                          raw_ostream &O);
85     bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
86                                unsigned AsmVariant, const char *ExtraCode,
87                                raw_ostream &O);
88 
89     MachineLocation getDebugValueLocation(const MachineInstr *MI) const {
90       MachineLocation Location;
91       assert(MI->getNumOperands() == 4 && "Invalid no. of machine operands!");
92       // Frame address.  Currently handles register +- offset only.
93       if (MI->getOperand(0).isReg() && MI->getOperand(2).isImm())
94         Location.set(MI->getOperand(0).getReg(), MI->getOperand(2).getImm());
95       else {
96         DEBUG(dbgs() << "DBG_VALUE instruction ignored! " << *MI << "\n");
97       }
98       return Location;
99     }
100   };
101 
102   /// PPCLinuxAsmPrinter - PowerPC assembly printer, customized for Linux
103   class PPCLinuxAsmPrinter : public PPCAsmPrinter {
104   public:
105     explicit PPCLinuxAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
106       : PPCAsmPrinter(TM, Streamer) {}
107 
108     virtual const char *getPassName() const {
109       return "Linux PPC Assembly Printer";
110     }
111 
112     bool doFinalization(Module &M);
113 
114     virtual void EmitFunctionEntryLabel();
115 
116     void EmitFunctionBodyEnd();
117   };
118 
119   /// PPCDarwinAsmPrinter - PowerPC assembly printer, customized for Darwin/Mac
120   /// OS X
121   class PPCDarwinAsmPrinter : public PPCAsmPrinter {
122   public:
123     explicit PPCDarwinAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
124       : PPCAsmPrinter(TM, Streamer) {}
125 
126     virtual const char *getPassName() const {
127       return "Darwin PPC Assembly Printer";
128     }
129 
130     bool doFinalization(Module &M);
131     void EmitStartOfAsmFile(Module &M);
132 
133     void EmitFunctionStubs(const MachineModuleInfoMachO::SymbolListTy &Stubs);
134   };
135 } // end of anonymous namespace
136 
137 /// stripRegisterPrefix - This method strips the character prefix from a
138 /// register name so that only the number is left.  Used by for linux asm.
139 static const char *stripRegisterPrefix(const char *RegName) {
140   switch (RegName[0]) {
141     case 'r':
142     case 'f':
143     case 'v': return RegName + 1;
144     case 'c': if (RegName[1] == 'r') return RegName + 2;
145   }
146 
147   return RegName;
148 }
149 
150 void PPCAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
151                                  raw_ostream &O) {
152   const MachineOperand &MO = MI->getOperand(OpNo);
153 
154   switch (MO.getType()) {
155   case MachineOperand::MO_Register: {
156     const char *RegName = PPCInstPrinter::getRegisterName(MO.getReg());
157     // Linux assembler (Others?) does not take register mnemonics.
158     // FIXME - What about special registers used in mfspr/mtspr?
159     if (!Subtarget.isDarwin()) RegName = stripRegisterPrefix(RegName);
160     O << RegName;
161     return;
162   }
163   case MachineOperand::MO_Immediate:
164     O << MO.getImm();
165     return;
166 
167   case MachineOperand::MO_MachineBasicBlock:
168     O << *MO.getMBB()->getSymbol();
169     return;
170   case MachineOperand::MO_JumpTableIndex:
171     O << MAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
172       << '_' << MO.getIndex();
173     // FIXME: PIC relocation model
174     return;
175   case MachineOperand::MO_ConstantPoolIndex:
176     O << MAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber()
177       << '_' << MO.getIndex();
178     return;
179   case MachineOperand::MO_BlockAddress:
180     O << *GetBlockAddressSymbol(MO.getBlockAddress());
181     return;
182   case MachineOperand::MO_ExternalSymbol: {
183     // Computing the address of an external symbol, not calling it.
184     if (TM.getRelocationModel() == Reloc::Static) {
185       O << *GetExternalSymbolSymbol(MO.getSymbolName());
186       return;
187     }
188 
189     MCSymbol *NLPSym =
190       OutContext.GetOrCreateSymbol(StringRef(MAI->getGlobalPrefix())+
191                                    MO.getSymbolName()+"$non_lazy_ptr");
192     MachineModuleInfoImpl::StubValueTy &StubSym =
193       MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(NLPSym);
194     if (StubSym.getPointer() == 0)
195       StubSym = MachineModuleInfoImpl::
196         StubValueTy(GetExternalSymbolSymbol(MO.getSymbolName()), true);
197 
198     O << *NLPSym;
199     return;
200   }
201   case MachineOperand::MO_GlobalAddress: {
202     // Computing the address of a global symbol, not calling it.
203     const GlobalValue *GV = MO.getGlobal();
204     MCSymbol *SymToPrint;
205 
206     // External or weakly linked global variables need non-lazily-resolved stubs
207     if (TM.getRelocationModel() != Reloc::Static &&
208         (GV->isDeclaration() || GV->isWeakForLinker())) {
209       if (!GV->hasHiddenVisibility()) {
210         SymToPrint = GetSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
211         MachineModuleInfoImpl::StubValueTy &StubSym =
212           MMI->getObjFileInfo<MachineModuleInfoMachO>()
213             .getGVStubEntry(SymToPrint);
214         if (StubSym.getPointer() == 0)
215           StubSym = MachineModuleInfoImpl::
216             StubValueTy(Mang->getSymbol(GV), !GV->hasInternalLinkage());
217       } else if (GV->isDeclaration() || GV->hasCommonLinkage() ||
218                  GV->hasAvailableExternallyLinkage()) {
219         SymToPrint = GetSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
220 
221         MachineModuleInfoImpl::StubValueTy &StubSym =
222           MMI->getObjFileInfo<MachineModuleInfoMachO>().
223                     getHiddenGVStubEntry(SymToPrint);
224         if (StubSym.getPointer() == 0)
225           StubSym = MachineModuleInfoImpl::
226             StubValueTy(Mang->getSymbol(GV), !GV->hasInternalLinkage());
227       } else {
228         SymToPrint = Mang->getSymbol(GV);
229       }
230     } else {
231       SymToPrint = Mang->getSymbol(GV);
232     }
233 
234     O << *SymToPrint;
235 
236     printOffset(MO.getOffset(), O);
237     return;
238   }
239 
240   default:
241     O << "<unknown operand type: " << MO.getType() << ">";
242     return;
243   }
244 }
245 
246 /// PrintAsmOperand - Print out an operand for an inline asm expression.
247 ///
248 bool PPCAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
249                                     unsigned AsmVariant,
250                                     const char *ExtraCode, raw_ostream &O) {
251   // Does this asm operand have a single letter operand modifier?
252   if (ExtraCode && ExtraCode[0]) {
253     if (ExtraCode[1] != 0) return true; // Unknown modifier.
254 
255     switch (ExtraCode[0]) {
256     default:
257       // See if this is a generic print operand
258       return AsmPrinter::PrintAsmOperand(MI, OpNo, AsmVariant, ExtraCode, O);
259     case 'c': // Don't print "$" before a global var name or constant.
260       break; // PPC never has a prefix.
261     case 'L': // Write second word of DImode reference.
262       // Verify that this operand has two consecutive registers.
263       if (!MI->getOperand(OpNo).isReg() ||
264           OpNo+1 == MI->getNumOperands() ||
265           !MI->getOperand(OpNo+1).isReg())
266         return true;
267       ++OpNo;   // Return the high-part.
268       break;
269     case 'I':
270       // Write 'i' if an integer constant, otherwise nothing.  Used to print
271       // addi vs add, etc.
272       if (MI->getOperand(OpNo).isImm())
273         O << "i";
274       return false;
275     }
276   }
277 
278   printOperand(MI, OpNo, O);
279   return false;
280 }
281 
282 // At the moment, all inline asm memory operands are a single register.
283 // In any case, the output of this routine should always be just one
284 // assembler operand.
285 
286 bool PPCAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
287                                           unsigned AsmVariant,
288                                           const char *ExtraCode,
289                                           raw_ostream &O) {
290   if (ExtraCode && ExtraCode[0]) {
291     if (ExtraCode[1] != 0) return true; // Unknown modifier.
292 
293     switch (ExtraCode[0]) {
294     default: return true;  // Unknown modifier.
295     case 'y': // A memory reference for an X-form instruction
296       {
297         const char *RegName = "r0";
298         if (!Subtarget.isDarwin()) RegName = stripRegisterPrefix(RegName);
299         O << RegName << ", ";
300         printOperand(MI, OpNo, O);
301         return false;
302       }
303     }
304   }
305 
306   assert(MI->getOperand(OpNo).isReg());
307   O << "0(";
308   printOperand(MI, OpNo, O);
309   O << ")";
310   return false;
311 }
312 
313 
314 /// lookUpOrCreateTOCEntry -- Given a symbol, look up whether a TOC entry
315 /// exists for it.  If not, create one.  Then return a symbol that references
316 /// the TOC entry.
317 MCSymbol *PPCAsmPrinter::lookUpOrCreateTOCEntry(MCSymbol *Sym) {
318 
319   MCSymbol *&TOCEntry = TOC[Sym];
320 
321   // To avoid name clash check if the name already exists.
322   while (TOCEntry == 0) {
323     if (OutContext.LookupSymbol(Twine(MAI->getPrivateGlobalPrefix()) +
324                                 "C" + Twine(TOCLabelID++)) == 0) {
325       TOCEntry = GetTempSymbol("C", TOCLabelID);
326     }
327   }
328 
329   return TOCEntry;
330 }
331 
332 
333 /// EmitInstruction -- Print out a single PowerPC MI in Darwin syntax to
334 /// the current output stream.
335 ///
336 void PPCAsmPrinter::EmitInstruction(const MachineInstr *MI) {
337   MCInst TmpInst;
338 
339   // Lower multi-instruction pseudo operations.
340   switch (MI->getOpcode()) {
341   default: break;
342   case TargetOpcode::DBG_VALUE: {
343     if (!isVerbose() || !OutStreamer.hasRawTextSupport()) return;
344 
345     SmallString<32> Str;
346     raw_svector_ostream O(Str);
347     unsigned NOps = MI->getNumOperands();
348     assert(NOps==4);
349     O << '\t' << MAI->getCommentString() << "DEBUG_VALUE: ";
350     // cast away const; DIetc do not take const operands for some reason.
351     DIVariable V(const_cast<MDNode *>(MI->getOperand(NOps-1).getMetadata()));
352     O << V.getName();
353     O << " <- ";
354     // Frame address.  Currently handles register +- offset only.
355     assert(MI->getOperand(0).isReg() && MI->getOperand(1).isImm());
356     O << '['; printOperand(MI, 0, O); O << '+'; printOperand(MI, 1, O);
357     O << ']';
358     O << "+";
359     printOperand(MI, NOps-2, O);
360     OutStreamer.EmitRawText(O.str());
361     return;
362   }
363 
364   case PPC::MovePCtoLR:
365   case PPC::MovePCtoLR8: {
366     // Transform %LR = MovePCtoLR
367     // Into this, where the label is the PIC base:
368     //     bl L1$pb
369     // L1$pb:
370     MCSymbol *PICBase = MF->getPICBaseSymbol();
371 
372     // Emit the 'bl'.
373     OutStreamer.EmitInstruction(MCInstBuilder(PPC::BL_Darwin) // Darwin vs SVR4 doesn't matter here.
374       // FIXME: We would like an efficient form for this, so we don't have to do
375       // a lot of extra uniquing.
376       .addExpr(MCSymbolRefExpr::Create(PICBase, OutContext)));
377 
378     // Emit the label.
379     OutStreamer.EmitLabel(PICBase);
380     return;
381   }
382   case PPC::LDtocJTI:
383   case PPC::LDtocCPT:
384   case PPC::LDtoc: {
385     // Transform %X3 = LDtoc <ga:@min1>, %X2
386     LowerPPCMachineInstrToMCInst(MI, TmpInst, *this, Subtarget.isDarwin());
387 
388     // Change the opcode to LD, and the global address operand to be a
389     // reference to the TOC entry we will synthesize later.
390     TmpInst.setOpcode(PPC::LD);
391     const MachineOperand &MO = MI->getOperand(1);
392 
393     // Map symbol -> label of TOC entry
394     assert(MO.isGlobal() || MO.isCPI() || MO.isJTI());
395     MCSymbol *MOSymbol = 0;
396     if (MO.isGlobal())
397       MOSymbol = Mang->getSymbol(MO.getGlobal());
398     else if (MO.isCPI())
399       MOSymbol = GetCPISymbol(MO.getIndex());
400     else if (MO.isJTI())
401       MOSymbol = GetJTISymbol(MO.getIndex());
402 
403     MCSymbol *TOCEntry = lookUpOrCreateTOCEntry(MOSymbol);
404 
405     const MCExpr *Exp =
406       MCSymbolRefExpr::Create(TOCEntry, MCSymbolRefExpr::VK_PPC_TOC_ENTRY,
407                               OutContext);
408     TmpInst.getOperand(1) = MCOperand::CreateExpr(Exp);
409     OutStreamer.EmitInstruction(TmpInst);
410     return;
411   }
412 
413   case PPC::ADDIStocHA: {
414     // Transform %Xd = ADDIStocHA %X2, <ga:@sym>
415     LowerPPCMachineInstrToMCInst(MI, TmpInst, *this, Subtarget.isDarwin());
416 
417     // Change the opcode to ADDIS8.  If the global address is external,
418     // has common linkage, is a function address, or is a jump table
419     // address, then generate a TOC entry and reference that.  Otherwise
420     // reference the symbol directly.
421     TmpInst.setOpcode(PPC::ADDIS8);
422     const MachineOperand &MO = MI->getOperand(2);
423     assert((MO.isGlobal() || MO.isCPI() || MO.isJTI()) &&
424            "Invalid operand for ADDIStocHA!");
425     MCSymbol *MOSymbol = 0;
426     bool IsExternal = false;
427     bool IsFunction = false;
428     bool IsCommon = false;
429 
430     if (MO.isGlobal()) {
431       const GlobalValue *GValue = MO.getGlobal();
432       MOSymbol = Mang->getSymbol(GValue);
433       const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GValue);
434       IsExternal = GVar && !GVar->hasInitializer();
435       IsCommon = GVar && GValue->hasCommonLinkage();
436       IsFunction = !GVar;
437     } else if (MO.isCPI())
438       MOSymbol = GetCPISymbol(MO.getIndex());
439     else if (MO.isJTI())
440       MOSymbol = GetJTISymbol(MO.getIndex());
441 
442     if (IsExternal || IsFunction || IsCommon || MO.isJTI())
443       MOSymbol = lookUpOrCreateTOCEntry(MOSymbol);
444 
445     const MCExpr *Exp =
446       MCSymbolRefExpr::Create(MOSymbol, MCSymbolRefExpr::VK_PPC_TOC16_HA,
447                               OutContext);
448     TmpInst.getOperand(2) = MCOperand::CreateExpr(Exp);
449     OutStreamer.EmitInstruction(TmpInst);
450     return;
451   }
452   case PPC::LDtocL: {
453     // Transform %Xd = LDtocL <ga:@sym>, %Xs
454     LowerPPCMachineInstrToMCInst(MI, TmpInst, *this, Subtarget.isDarwin());
455 
456     // Change the opcode to LDrs, which is a form of LD with the offset
457     // specified by a SymbolLo.  If the global address is external, has
458     // common linkage, or is a jump table address, then reference the
459     // associated TOC entry.  Otherwise reference the symbol directly.
460     TmpInst.setOpcode(PPC::LDrs);
461     const MachineOperand &MO = MI->getOperand(1);
462     assert((MO.isGlobal() || MO.isJTI()) && "Invalid operand for LDtocL!");
463     MCSymbol *MOSymbol = 0;
464 
465     if (MO.isJTI())
466       MOSymbol = lookUpOrCreateTOCEntry(GetJTISymbol(MO.getIndex()));
467     else {
468       const GlobalValue *GValue = MO.getGlobal();
469       MOSymbol = Mang->getSymbol(GValue);
470       const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GValue);
471 
472       if (!GVar || !GVar->hasInitializer() || GValue->hasCommonLinkage())
473         MOSymbol = lookUpOrCreateTOCEntry(MOSymbol);
474     }
475 
476     const MCExpr *Exp =
477       MCSymbolRefExpr::Create(MOSymbol, MCSymbolRefExpr::VK_PPC_TOC16_LO,
478                               OutContext);
479     TmpInst.getOperand(1) = MCOperand::CreateExpr(Exp);
480     OutStreamer.EmitInstruction(TmpInst);
481     return;
482   }
483   case PPC::ADDItocL: {
484     // Transform %Xd = ADDItocL %Xs, <ga:@sym>
485     LowerPPCMachineInstrToMCInst(MI, TmpInst, *this, Subtarget.isDarwin());
486 
487     // Change the opcode to ADDI8L.  If the global address is external, then
488     // generate a TOC entry and reference that.  Otherwise reference the
489     // symbol directly.
490     TmpInst.setOpcode(PPC::ADDI8L);
491     const MachineOperand &MO = MI->getOperand(2);
492     assert((MO.isGlobal() || MO.isCPI()) && "Invalid operand for ADDItocL");
493     MCSymbol *MOSymbol = 0;
494     bool IsExternal = false;
495     bool IsFunction = false;
496 
497     if (MO.isGlobal()) {
498       const GlobalValue *GValue = MO.getGlobal();
499       MOSymbol = Mang->getSymbol(GValue);
500       const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GValue);
501       IsExternal = GVar && !GVar->hasInitializer();
502       IsFunction = !GVar;
503     } else if (MO.isCPI())
504       MOSymbol = GetCPISymbol(MO.getIndex());
505 
506     if (IsFunction || IsExternal)
507       MOSymbol = lookUpOrCreateTOCEntry(MOSymbol);
508 
509     const MCExpr *Exp =
510       MCSymbolRefExpr::Create(MOSymbol, MCSymbolRefExpr::VK_PPC_TOC16_LO,
511                               OutContext);
512     TmpInst.getOperand(2) = MCOperand::CreateExpr(Exp);
513     OutStreamer.EmitInstruction(TmpInst);
514     return;
515   }
516   case PPC::MFCRpseud:
517   case PPC::MFCR8pseud:
518     // Transform: %R3 = MFCRpseud %CR7
519     // Into:      %R3 = MFCR      ;; cr7
520     OutStreamer.AddComment(PPCInstPrinter::
521                            getRegisterName(MI->getOperand(1).getReg()));
522     OutStreamer.EmitInstruction(MCInstBuilder(Subtarget.isPPC64() ? PPC::MFCR8 : PPC::MFCR)
523       .addReg(MI->getOperand(0).getReg()));
524     return;
525   case PPC::SYNC:
526     // In Book E sync is called msync, handle this special case here...
527     if (Subtarget.isBookE()) {
528       OutStreamer.EmitRawText(StringRef("\tmsync"));
529       return;
530     }
531   }
532 
533   LowerPPCMachineInstrToMCInst(MI, TmpInst, *this, Subtarget.isDarwin());
534   OutStreamer.EmitInstruction(TmpInst);
535 }
536 
537 void PPCLinuxAsmPrinter::EmitFunctionEntryLabel() {
538   if (!Subtarget.isPPC64())  // linux/ppc32 - Normal entry label.
539     return AsmPrinter::EmitFunctionEntryLabel();
540 
541   // Emit an official procedure descriptor.
542   const MCSection *Current = OutStreamer.getCurrentSection();
543   const MCSectionELF *Section = OutStreamer.getContext().getELFSection(".opd",
544       ELF::SHT_PROGBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC,
545       SectionKind::getReadOnly());
546   OutStreamer.SwitchSection(Section);
547   OutStreamer.EmitLabel(CurrentFnSym);
548   OutStreamer.EmitValueToAlignment(8);
549   MCSymbol *Symbol1 =
550     OutContext.GetOrCreateSymbol(".L." + Twine(CurrentFnSym->getName()));
551   // Generates a R_PPC64_ADDR64 (from FK_DATA_8) relocation for the function
552   // entry point.
553   OutStreamer.EmitValue(MCSymbolRefExpr::Create(Symbol1, OutContext),
554                         8/*size*/, 0/*addrspace*/);
555   MCSymbol *Symbol2 = OutContext.GetOrCreateSymbol(StringRef(".TOC."));
556   // Generates a R_PPC64_TOC relocation for TOC base insertion.
557   OutStreamer.EmitValue(MCSymbolRefExpr::Create(Symbol2,
558                         MCSymbolRefExpr::VK_PPC_TOC, OutContext),
559                         8/*size*/, 0/*addrspace*/);
560   // Emit a null environment pointer.
561   OutStreamer.EmitIntValue(0, 8 /* size */, 0 /* addrspace */);
562   OutStreamer.SwitchSection(Current);
563 
564   MCSymbol *RealFnSym = OutContext.GetOrCreateSymbol(
565                           ".L." + Twine(CurrentFnSym->getName()));
566   OutStreamer.EmitLabel(RealFnSym);
567   CurrentFnSymForSize = RealFnSym;
568 }
569 
570 
571 bool PPCLinuxAsmPrinter::doFinalization(Module &M) {
572   const DataLayout *TD = TM.getDataLayout();
573 
574   bool isPPC64 = TD->getPointerSizeInBits() == 64;
575 
576   if (isPPC64 && !TOC.empty()) {
577     const MCSectionELF *Section = OutStreamer.getContext().getELFSection(".toc",
578         ELF::SHT_PROGBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC,
579         SectionKind::getReadOnly());
580     OutStreamer.SwitchSection(Section);
581 
582     for (MapVector<MCSymbol*, MCSymbol*>::iterator I = TOC.begin(),
583          E = TOC.end(); I != E; ++I) {
584       OutStreamer.EmitLabel(I->second);
585       MCSymbol *S = OutContext.GetOrCreateSymbol(I->first->getName());
586       OutStreamer.EmitTCEntry(*S);
587     }
588   }
589 
590   return AsmPrinter::doFinalization(M);
591 }
592 
593 /// EmitFunctionBodyEnd - Print the traceback table before the .size
594 /// directive.
595 ///
596 void PPCLinuxAsmPrinter::EmitFunctionBodyEnd() {
597   // Only the 64-bit target requires a traceback table.  For now,
598   // we only emit the word of zeroes that GDB requires to find
599   // the end of the function, and zeroes for the eight-byte
600   // mandatory fields.
601   // FIXME: We should fill in the eight-byte mandatory fields as described in
602   // the PPC64 ELF ABI (this is a low-priority item because GDB does not
603   // currently make use of these fields).
604   if (Subtarget.isPPC64()) {
605     OutStreamer.EmitIntValue(0, 4/*size*/);
606     OutStreamer.EmitIntValue(0, 8/*size*/);
607   }
608 }
609 
610 void PPCDarwinAsmPrinter::EmitStartOfAsmFile(Module &M) {
611   static const char *const CPUDirectives[] = {
612     "",
613     "ppc",
614     "ppc440",
615     "ppc601",
616     "ppc602",
617     "ppc603",
618     "ppc7400",
619     "ppc750",
620     "ppc970",
621     "ppcA2",
622     "ppce500mc",
623     "ppce5500",
624     "power6",
625     "power7",
626     "ppc64"
627   };
628 
629   unsigned Directive = Subtarget.getDarwinDirective();
630   if (Subtarget.hasMFOCRF() && Directive < PPC::DIR_970)
631     Directive = PPC::DIR_970;
632   if (Subtarget.hasAltivec() && Directive < PPC::DIR_7400)
633     Directive = PPC::DIR_7400;
634   if (Subtarget.isPPC64() && Directive < PPC::DIR_64)
635     Directive = PPC::DIR_64;
636   assert(Directive <= PPC::DIR_64 && "Directive out of range.");
637 
638   // FIXME: This is a total hack, finish mc'izing the PPC backend.
639   if (OutStreamer.hasRawTextSupport())
640     OutStreamer.EmitRawText("\t.machine " + Twine(CPUDirectives[Directive]));
641 
642   // Prime text sections so they are adjacent.  This reduces the likelihood a
643   // large data or debug section causes a branch to exceed 16M limit.
644   const TargetLoweringObjectFileMachO &TLOFMacho =
645     static_cast<const TargetLoweringObjectFileMachO &>(getObjFileLowering());
646   OutStreamer.SwitchSection(TLOFMacho.getTextCoalSection());
647   if (TM.getRelocationModel() == Reloc::PIC_) {
648     OutStreamer.SwitchSection(
649            OutContext.getMachOSection("__TEXT", "__picsymbolstub1",
650                                       MCSectionMachO::S_SYMBOL_STUBS |
651                                       MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
652                                       32, SectionKind::getText()));
653   } else if (TM.getRelocationModel() == Reloc::DynamicNoPIC) {
654     OutStreamer.SwitchSection(
655            OutContext.getMachOSection("__TEXT","__symbol_stub1",
656                                       MCSectionMachO::S_SYMBOL_STUBS |
657                                       MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
658                                       16, SectionKind::getText()));
659   }
660   OutStreamer.SwitchSection(getObjFileLowering().getTextSection());
661 }
662 
663 static MCSymbol *GetLazyPtr(MCSymbol *Sym, MCContext &Ctx) {
664   // Remove $stub suffix, add $lazy_ptr.
665   StringRef NoStub = Sym->getName().substr(0, Sym->getName().size()-5);
666   return Ctx.GetOrCreateSymbol(NoStub + "$lazy_ptr");
667 }
668 
669 static MCSymbol *GetAnonSym(MCSymbol *Sym, MCContext &Ctx) {
670   // Add $tmp suffix to $stub, yielding $stub$tmp.
671   return Ctx.GetOrCreateSymbol(Sym->getName() + "$tmp");
672 }
673 
674 void PPCDarwinAsmPrinter::
675 EmitFunctionStubs(const MachineModuleInfoMachO::SymbolListTy &Stubs) {
676   bool isPPC64 = TM.getDataLayout()->getPointerSizeInBits() == 64;
677 
678   const TargetLoweringObjectFileMachO &TLOFMacho =
679     static_cast<const TargetLoweringObjectFileMachO &>(getObjFileLowering());
680 
681   // .lazy_symbol_pointer
682   const MCSection *LSPSection = TLOFMacho.getLazySymbolPointerSection();
683 
684   // Output stubs for dynamically-linked functions
685   if (TM.getRelocationModel() == Reloc::PIC_) {
686     const MCSection *StubSection =
687     OutContext.getMachOSection("__TEXT", "__picsymbolstub1",
688                                MCSectionMachO::S_SYMBOL_STUBS |
689                                MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
690                                32, SectionKind::getText());
691     for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
692       OutStreamer.SwitchSection(StubSection);
693       EmitAlignment(4);
694 
695       MCSymbol *Stub = Stubs[i].first;
696       MCSymbol *RawSym = Stubs[i].second.getPointer();
697       MCSymbol *LazyPtr = GetLazyPtr(Stub, OutContext);
698       MCSymbol *AnonSymbol = GetAnonSym(Stub, OutContext);
699 
700       OutStreamer.EmitLabel(Stub);
701       OutStreamer.EmitSymbolAttribute(RawSym, MCSA_IndirectSymbol);
702 
703       // mflr r0
704       OutStreamer.EmitInstruction(MCInstBuilder(PPC::MFLR).addReg(PPC::R0));
705       // FIXME: MCize this.
706       OutStreamer.EmitRawText("\tbcl 20, 31, " + Twine(AnonSymbol->getName()));
707       OutStreamer.EmitLabel(AnonSymbol);
708       // mflr r11
709       OutStreamer.EmitInstruction(MCInstBuilder(PPC::MFLR).addReg(PPC::R11));
710       // addis r11, r11, ha16(LazyPtr - AnonSymbol)
711       const MCExpr *Sub =
712         MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(LazyPtr, OutContext),
713                                 MCSymbolRefExpr::Create(AnonSymbol, OutContext),
714                                 OutContext);
715       OutStreamer.EmitInstruction(MCInstBuilder(PPC::ADDIS)
716         .addReg(PPC::R11)
717         .addReg(PPC::R11)
718         .addExpr(Sub));
719       // mtlr r0
720       OutStreamer.EmitInstruction(MCInstBuilder(PPC::MTLR).addReg(PPC::R0));
721 
722       // ldu r12, lo16(LazyPtr - AnonSymbol)(r11)
723       // lwzu r12, lo16(LazyPtr - AnonSymbol)(r11)
724       OutStreamer.EmitInstruction(MCInstBuilder(isPPC64 ? PPC::LDU : PPC::LWZU)
725         .addReg(PPC::R12)
726         .addExpr(Sub).addExpr(Sub)
727         .addReg(PPC::R11));
728       // mtctr r12
729       OutStreamer.EmitInstruction(MCInstBuilder(PPC::MTCTR).addReg(PPC::R12));
730       // bctr
731       OutStreamer.EmitInstruction(MCInstBuilder(PPC::BCTR));
732 
733       OutStreamer.SwitchSection(LSPSection);
734       OutStreamer.EmitLabel(LazyPtr);
735       OutStreamer.EmitSymbolAttribute(RawSym, MCSA_IndirectSymbol);
736 
737       MCSymbol *DyldStubBindingHelper =
738         OutContext.GetOrCreateSymbol(StringRef("dyld_stub_binding_helper"));
739       if (isPPC64) {
740         // .quad dyld_stub_binding_helper
741         OutStreamer.EmitSymbolValue(DyldStubBindingHelper, 8);
742       } else {
743         // .long dyld_stub_binding_helper
744         OutStreamer.EmitSymbolValue(DyldStubBindingHelper, 4);
745       }
746     }
747     OutStreamer.AddBlankLine();
748     return;
749   }
750 
751   const MCSection *StubSection =
752     OutContext.getMachOSection("__TEXT","__symbol_stub1",
753                                MCSectionMachO::S_SYMBOL_STUBS |
754                                MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
755                                16, SectionKind::getText());
756   for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
757     MCSymbol *Stub = Stubs[i].first;
758     MCSymbol *RawSym = Stubs[i].second.getPointer();
759     MCSymbol *LazyPtr = GetLazyPtr(Stub, OutContext);
760 
761     OutStreamer.SwitchSection(StubSection);
762     EmitAlignment(4);
763     OutStreamer.EmitLabel(Stub);
764     OutStreamer.EmitSymbolAttribute(RawSym, MCSA_IndirectSymbol);
765     // lis r11, ha16(LazyPtr)
766     const MCExpr *LazyPtrHa16 =
767       MCSymbolRefExpr::Create(LazyPtr, MCSymbolRefExpr::VK_PPC_DARWIN_HA16,
768                               OutContext);
769     OutStreamer.EmitInstruction(MCInstBuilder(PPC::LIS)
770       .addReg(PPC::R11)
771       .addExpr(LazyPtrHa16));
772 
773     const MCExpr *LazyPtrLo16 =
774       MCSymbolRefExpr::Create(LazyPtr, MCSymbolRefExpr::VK_PPC_DARWIN_LO16,
775                               OutContext);
776     // ldu r12, lo16(LazyPtr)(r11)
777     // lwzu r12, lo16(LazyPtr)(r11)
778     OutStreamer.EmitInstruction(MCInstBuilder(isPPC64 ? PPC::LDU : PPC::LWZU)
779       .addReg(PPC::R12)
780       .addExpr(LazyPtrLo16).addExpr(LazyPtrLo16)
781       .addReg(PPC::R11));
782 
783     // mtctr r12
784     OutStreamer.EmitInstruction(MCInstBuilder(PPC::MTCTR).addReg(PPC::R12));
785     // bctr
786     OutStreamer.EmitInstruction(MCInstBuilder(PPC::BCTR));
787 
788     OutStreamer.SwitchSection(LSPSection);
789     OutStreamer.EmitLabel(LazyPtr);
790     OutStreamer.EmitSymbolAttribute(RawSym, MCSA_IndirectSymbol);
791 
792     MCSymbol *DyldStubBindingHelper =
793       OutContext.GetOrCreateSymbol(StringRef("dyld_stub_binding_helper"));
794     if (isPPC64) {
795       // .quad dyld_stub_binding_helper
796       OutStreamer.EmitSymbolValue(DyldStubBindingHelper, 8);
797     } else {
798       // .long dyld_stub_binding_helper
799       OutStreamer.EmitSymbolValue(DyldStubBindingHelper, 4);
800     }
801   }
802 
803   OutStreamer.AddBlankLine();
804 }
805 
806 
807 bool PPCDarwinAsmPrinter::doFinalization(Module &M) {
808   bool isPPC64 = TM.getDataLayout()->getPointerSizeInBits() == 64;
809 
810   // Darwin/PPC always uses mach-o.
811   const TargetLoweringObjectFileMachO &TLOFMacho =
812     static_cast<const TargetLoweringObjectFileMachO &>(getObjFileLowering());
813   MachineModuleInfoMachO &MMIMacho =
814     MMI->getObjFileInfo<MachineModuleInfoMachO>();
815 
816   MachineModuleInfoMachO::SymbolListTy Stubs = MMIMacho.GetFnStubList();
817   if (!Stubs.empty())
818     EmitFunctionStubs(Stubs);
819 
820   if (MAI->doesSupportExceptionHandling() && MMI) {
821     // Add the (possibly multiple) personalities to the set of global values.
822     // Only referenced functions get into the Personalities list.
823     const std::vector<const Function*> &Personalities = MMI->getPersonalities();
824     for (std::vector<const Function*>::const_iterator I = Personalities.begin(),
825          E = Personalities.end(); I != E; ++I) {
826       if (*I) {
827         MCSymbol *NLPSym = GetSymbolWithGlobalValueBase(*I, "$non_lazy_ptr");
828         MachineModuleInfoImpl::StubValueTy &StubSym =
829           MMIMacho.getGVStubEntry(NLPSym);
830         StubSym = MachineModuleInfoImpl::StubValueTy(Mang->getSymbol(*I), true);
831       }
832     }
833   }
834 
835   // Output stubs for dynamically-linked functions.
836   Stubs = MMIMacho.GetGVStubList();
837 
838   // Output macho stubs for external and common global variables.
839   if (!Stubs.empty()) {
840     // Switch with ".non_lazy_symbol_pointer" directive.
841     OutStreamer.SwitchSection(TLOFMacho.getNonLazySymbolPointerSection());
842     EmitAlignment(isPPC64 ? 3 : 2);
843 
844     for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
845       // L_foo$stub:
846       OutStreamer.EmitLabel(Stubs[i].first);
847       //   .indirect_symbol _foo
848       MachineModuleInfoImpl::StubValueTy &MCSym = Stubs[i].second;
849       OutStreamer.EmitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
850 
851       if (MCSym.getInt())
852         // External to current translation unit.
853         OutStreamer.EmitIntValue(0, isPPC64 ? 8 : 4/*size*/, 0/*addrspace*/);
854       else
855         // Internal to current translation unit.
856         //
857         // When we place the LSDA into the TEXT section, the type info pointers
858         // need to be indirect and pc-rel. We accomplish this by using NLPs.
859         // However, sometimes the types are local to the file. So we need to
860         // fill in the value for the NLP in those cases.
861         OutStreamer.EmitValue(MCSymbolRefExpr::Create(MCSym.getPointer(),
862                                                       OutContext),
863                               isPPC64 ? 8 : 4/*size*/, 0/*addrspace*/);
864     }
865 
866     Stubs.clear();
867     OutStreamer.AddBlankLine();
868   }
869 
870   Stubs = MMIMacho.GetHiddenGVStubList();
871   if (!Stubs.empty()) {
872     OutStreamer.SwitchSection(getObjFileLowering().getDataSection());
873     EmitAlignment(isPPC64 ? 3 : 2);
874 
875     for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
876       // L_foo$stub:
877       OutStreamer.EmitLabel(Stubs[i].first);
878       //   .long _foo
879       OutStreamer.EmitValue(MCSymbolRefExpr::
880                             Create(Stubs[i].second.getPointer(),
881                                    OutContext),
882                             isPPC64 ? 8 : 4/*size*/, 0/*addrspace*/);
883     }
884 
885     Stubs.clear();
886     OutStreamer.AddBlankLine();
887   }
888 
889   // Funny Darwin hack: This flag tells the linker that no global symbols
890   // contain code that falls through to other global symbols (e.g. the obvious
891   // implementation of multiple entry points).  If this doesn't occur, the
892   // linker can safely perform dead code stripping.  Since LLVM never generates
893   // code that does this, it is always safe to set.
894   OutStreamer.EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
895 
896   return AsmPrinter::doFinalization(M);
897 }
898 
899 /// createPPCAsmPrinterPass - Returns a pass that prints the PPC assembly code
900 /// for a MachineFunction to the given output stream, in a format that the
901 /// Darwin assembler can deal with.
902 ///
903 static AsmPrinter *createPPCAsmPrinterPass(TargetMachine &tm,
904                                            MCStreamer &Streamer) {
905   const PPCSubtarget *Subtarget = &tm.getSubtarget<PPCSubtarget>();
906 
907   if (Subtarget->isDarwin())
908     return new PPCDarwinAsmPrinter(tm, Streamer);
909   return new PPCLinuxAsmPrinter(tm, Streamer);
910 }
911 
912 // Force static initialization.
913 extern "C" void LLVMInitializePowerPCAsmPrinter() {
914   TargetRegistry::RegisterAsmPrinter(ThePPC32Target, createPPCAsmPrinterPass);
915   TargetRegistry::RegisterAsmPrinter(ThePPC64Target, createPPCAsmPrinterPass);
916 }
917