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 "InstPrinter/PPCInstPrinter.h"
22 #include "MCTargetDesc/PPCPredicates.h"
23 #include "PPCSubtarget.h"
24 #include "PPCTargetMachine.h"
25 #include "llvm/ADT/MapVector.h"
26 #include "llvm/ADT/SmallString.h"
27 #include "llvm/ADT/StringExtras.h"
28 #include "llvm/Assembly/Writer.h"
29 #include "llvm/CodeGen/AsmPrinter.h"
30 #include "llvm/CodeGen/MachineFunctionPass.h"
31 #include "llvm/CodeGen/MachineInstr.h"
32 #include "llvm/CodeGen/MachineInstrBuilder.h"
33 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
34 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
35 #include "llvm/Constants.h"
36 #include "llvm/DebugInfo.h"
37 #include "llvm/DerivedTypes.h"
38 #include "llvm/MC/MCAsmInfo.h"
39 #include "llvm/MC/MCContext.h"
40 #include "llvm/MC/MCExpr.h"
41 #include "llvm/MC/MCInst.h"
42 #include "llvm/MC/MCInstBuilder.h"
43 #include "llvm/MC/MCSectionELF.h"
44 #include "llvm/MC/MCSectionMachO.h"
45 #include "llvm/MC/MCStreamer.h"
46 #include "llvm/MC/MCSymbol.h"
47 #include "llvm/Module.h"
48 #include "llvm/Support/CommandLine.h"
49 #include "llvm/Support/Debug.h"
50 #include "llvm/Support/ELF.h"
51 #include "llvm/Support/ErrorHandling.h"
52 #include "llvm/Support/MathExtras.h"
53 #include "llvm/Support/TargetRegistry.h"
54 #include "llvm/Support/raw_ostream.h"
55 #include "llvm/Target/Mangler.h"
56 #include "llvm/Target/TargetInstrInfo.h"
57 #include "llvm/Target/TargetOptions.h"
58 #include "llvm/Target/TargetRegisterInfo.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::LDgotTPREL: {
517     // Transform %Xd = LDgotTPREL <ga:@sym>, %Xs
518     LowerPPCMachineInstrToMCInst(MI, TmpInst, *this, Subtarget.isDarwin());
519 
520     // Change the opcode to LDrs, which is a form of LD with the offset
521     // specified by a SymbolLo.
522     TmpInst.setOpcode(PPC::LDrs);
523     const MachineOperand &MO = MI->getOperand(1);
524     const GlobalValue *GValue = MO.getGlobal();
525     MCSymbol *MOSymbol = Mang->getSymbol(GValue);
526     const MCExpr *Exp =
527       MCSymbolRefExpr::Create(MOSymbol, MCSymbolRefExpr::VK_PPC_GOT_TPREL16_DS,
528                               OutContext);
529     TmpInst.getOperand(1) = MCOperand::CreateExpr(Exp);
530     OutStreamer.EmitInstruction(TmpInst);
531     return;
532   }
533   case PPC::MFCRpseud:
534   case PPC::MFCR8pseud:
535     // Transform: %R3 = MFCRpseud %CR7
536     // Into:      %R3 = MFCR      ;; cr7
537     OutStreamer.AddComment(PPCInstPrinter::
538                            getRegisterName(MI->getOperand(1).getReg()));
539     OutStreamer.EmitInstruction(MCInstBuilder(Subtarget.isPPC64() ? PPC::MFCR8 : PPC::MFCR)
540       .addReg(MI->getOperand(0).getReg()));
541     return;
542   case PPC::SYNC:
543     // In Book E sync is called msync, handle this special case here...
544     if (Subtarget.isBookE()) {
545       OutStreamer.EmitRawText(StringRef("\tmsync"));
546       return;
547     }
548   }
549 
550   LowerPPCMachineInstrToMCInst(MI, TmpInst, *this, Subtarget.isDarwin());
551   OutStreamer.EmitInstruction(TmpInst);
552 }
553 
554 void PPCLinuxAsmPrinter::EmitFunctionEntryLabel() {
555   if (!Subtarget.isPPC64())  // linux/ppc32 - Normal entry label.
556     return AsmPrinter::EmitFunctionEntryLabel();
557 
558   // Emit an official procedure descriptor.
559   const MCSection *Current = OutStreamer.getCurrentSection();
560   const MCSectionELF *Section = OutStreamer.getContext().getELFSection(".opd",
561       ELF::SHT_PROGBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC,
562       SectionKind::getReadOnly());
563   OutStreamer.SwitchSection(Section);
564   OutStreamer.EmitLabel(CurrentFnSym);
565   OutStreamer.EmitValueToAlignment(8);
566   MCSymbol *Symbol1 =
567     OutContext.GetOrCreateSymbol(".L." + Twine(CurrentFnSym->getName()));
568   // Generates a R_PPC64_ADDR64 (from FK_DATA_8) relocation for the function
569   // entry point.
570   OutStreamer.EmitValue(MCSymbolRefExpr::Create(Symbol1, OutContext),
571                         8/*size*/, 0/*addrspace*/);
572   MCSymbol *Symbol2 = OutContext.GetOrCreateSymbol(StringRef(".TOC."));
573   // Generates a R_PPC64_TOC relocation for TOC base insertion.
574   OutStreamer.EmitValue(MCSymbolRefExpr::Create(Symbol2,
575                         MCSymbolRefExpr::VK_PPC_TOC, OutContext),
576                         8/*size*/, 0/*addrspace*/);
577   // Emit a null environment pointer.
578   OutStreamer.EmitIntValue(0, 8 /* size */, 0 /* addrspace */);
579   OutStreamer.SwitchSection(Current);
580 
581   MCSymbol *RealFnSym = OutContext.GetOrCreateSymbol(
582                           ".L." + Twine(CurrentFnSym->getName()));
583   OutStreamer.EmitLabel(RealFnSym);
584   CurrentFnSymForSize = RealFnSym;
585 }
586 
587 
588 bool PPCLinuxAsmPrinter::doFinalization(Module &M) {
589   const DataLayout *TD = TM.getDataLayout();
590 
591   bool isPPC64 = TD->getPointerSizeInBits() == 64;
592 
593   if (isPPC64 && !TOC.empty()) {
594     const MCSectionELF *Section = OutStreamer.getContext().getELFSection(".toc",
595         ELF::SHT_PROGBITS, ELF::SHF_WRITE | ELF::SHF_ALLOC,
596         SectionKind::getReadOnly());
597     OutStreamer.SwitchSection(Section);
598 
599     for (MapVector<MCSymbol*, MCSymbol*>::iterator I = TOC.begin(),
600          E = TOC.end(); I != E; ++I) {
601       OutStreamer.EmitLabel(I->second);
602       MCSymbol *S = OutContext.GetOrCreateSymbol(I->first->getName());
603       OutStreamer.EmitTCEntry(*S);
604     }
605   }
606 
607   return AsmPrinter::doFinalization(M);
608 }
609 
610 /// EmitFunctionBodyEnd - Print the traceback table before the .size
611 /// directive.
612 ///
613 void PPCLinuxAsmPrinter::EmitFunctionBodyEnd() {
614   // Only the 64-bit target requires a traceback table.  For now,
615   // we only emit the word of zeroes that GDB requires to find
616   // the end of the function, and zeroes for the eight-byte
617   // mandatory fields.
618   // FIXME: We should fill in the eight-byte mandatory fields as described in
619   // the PPC64 ELF ABI (this is a low-priority item because GDB does not
620   // currently make use of these fields).
621   if (Subtarget.isPPC64()) {
622     OutStreamer.EmitIntValue(0, 4/*size*/);
623     OutStreamer.EmitIntValue(0, 8/*size*/);
624   }
625 }
626 
627 void PPCDarwinAsmPrinter::EmitStartOfAsmFile(Module &M) {
628   static const char *const CPUDirectives[] = {
629     "",
630     "ppc",
631     "ppc440",
632     "ppc601",
633     "ppc602",
634     "ppc603",
635     "ppc7400",
636     "ppc750",
637     "ppc970",
638     "ppcA2",
639     "ppce500mc",
640     "ppce5500",
641     "power6",
642     "power7",
643     "ppc64"
644   };
645 
646   unsigned Directive = Subtarget.getDarwinDirective();
647   if (Subtarget.hasMFOCRF() && Directive < PPC::DIR_970)
648     Directive = PPC::DIR_970;
649   if (Subtarget.hasAltivec() && Directive < PPC::DIR_7400)
650     Directive = PPC::DIR_7400;
651   if (Subtarget.isPPC64() && Directive < PPC::DIR_64)
652     Directive = PPC::DIR_64;
653   assert(Directive <= PPC::DIR_64 && "Directive out of range.");
654 
655   // FIXME: This is a total hack, finish mc'izing the PPC backend.
656   if (OutStreamer.hasRawTextSupport())
657     OutStreamer.EmitRawText("\t.machine " + Twine(CPUDirectives[Directive]));
658 
659   // Prime text sections so they are adjacent.  This reduces the likelihood a
660   // large data or debug section causes a branch to exceed 16M limit.
661   const TargetLoweringObjectFileMachO &TLOFMacho =
662     static_cast<const TargetLoweringObjectFileMachO &>(getObjFileLowering());
663   OutStreamer.SwitchSection(TLOFMacho.getTextCoalSection());
664   if (TM.getRelocationModel() == Reloc::PIC_) {
665     OutStreamer.SwitchSection(
666            OutContext.getMachOSection("__TEXT", "__picsymbolstub1",
667                                       MCSectionMachO::S_SYMBOL_STUBS |
668                                       MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
669                                       32, SectionKind::getText()));
670   } else if (TM.getRelocationModel() == Reloc::DynamicNoPIC) {
671     OutStreamer.SwitchSection(
672            OutContext.getMachOSection("__TEXT","__symbol_stub1",
673                                       MCSectionMachO::S_SYMBOL_STUBS |
674                                       MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
675                                       16, SectionKind::getText()));
676   }
677   OutStreamer.SwitchSection(getObjFileLowering().getTextSection());
678 }
679 
680 static MCSymbol *GetLazyPtr(MCSymbol *Sym, MCContext &Ctx) {
681   // Remove $stub suffix, add $lazy_ptr.
682   StringRef NoStub = Sym->getName().substr(0, Sym->getName().size()-5);
683   return Ctx.GetOrCreateSymbol(NoStub + "$lazy_ptr");
684 }
685 
686 static MCSymbol *GetAnonSym(MCSymbol *Sym, MCContext &Ctx) {
687   // Add $tmp suffix to $stub, yielding $stub$tmp.
688   return Ctx.GetOrCreateSymbol(Sym->getName() + "$tmp");
689 }
690 
691 void PPCDarwinAsmPrinter::
692 EmitFunctionStubs(const MachineModuleInfoMachO::SymbolListTy &Stubs) {
693   bool isPPC64 = TM.getDataLayout()->getPointerSizeInBits() == 64;
694 
695   const TargetLoweringObjectFileMachO &TLOFMacho =
696     static_cast<const TargetLoweringObjectFileMachO &>(getObjFileLowering());
697 
698   // .lazy_symbol_pointer
699   const MCSection *LSPSection = TLOFMacho.getLazySymbolPointerSection();
700 
701   // Output stubs for dynamically-linked functions
702   if (TM.getRelocationModel() == Reloc::PIC_) {
703     const MCSection *StubSection =
704     OutContext.getMachOSection("__TEXT", "__picsymbolstub1",
705                                MCSectionMachO::S_SYMBOL_STUBS |
706                                MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
707                                32, SectionKind::getText());
708     for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
709       OutStreamer.SwitchSection(StubSection);
710       EmitAlignment(4);
711 
712       MCSymbol *Stub = Stubs[i].first;
713       MCSymbol *RawSym = Stubs[i].second.getPointer();
714       MCSymbol *LazyPtr = GetLazyPtr(Stub, OutContext);
715       MCSymbol *AnonSymbol = GetAnonSym(Stub, OutContext);
716 
717       OutStreamer.EmitLabel(Stub);
718       OutStreamer.EmitSymbolAttribute(RawSym, MCSA_IndirectSymbol);
719 
720       // mflr r0
721       OutStreamer.EmitInstruction(MCInstBuilder(PPC::MFLR).addReg(PPC::R0));
722       // FIXME: MCize this.
723       OutStreamer.EmitRawText("\tbcl 20, 31, " + Twine(AnonSymbol->getName()));
724       OutStreamer.EmitLabel(AnonSymbol);
725       // mflr r11
726       OutStreamer.EmitInstruction(MCInstBuilder(PPC::MFLR).addReg(PPC::R11));
727       // addis r11, r11, ha16(LazyPtr - AnonSymbol)
728       const MCExpr *Sub =
729         MCBinaryExpr::CreateSub(MCSymbolRefExpr::Create(LazyPtr, OutContext),
730                                 MCSymbolRefExpr::Create(AnonSymbol, OutContext),
731                                 OutContext);
732       OutStreamer.EmitInstruction(MCInstBuilder(PPC::ADDIS)
733         .addReg(PPC::R11)
734         .addReg(PPC::R11)
735         .addExpr(Sub));
736       // mtlr r0
737       OutStreamer.EmitInstruction(MCInstBuilder(PPC::MTLR).addReg(PPC::R0));
738 
739       // ldu r12, lo16(LazyPtr - AnonSymbol)(r11)
740       // lwzu r12, lo16(LazyPtr - AnonSymbol)(r11)
741       OutStreamer.EmitInstruction(MCInstBuilder(isPPC64 ? PPC::LDU : PPC::LWZU)
742         .addReg(PPC::R12)
743         .addExpr(Sub).addExpr(Sub)
744         .addReg(PPC::R11));
745       // mtctr r12
746       OutStreamer.EmitInstruction(MCInstBuilder(PPC::MTCTR).addReg(PPC::R12));
747       // bctr
748       OutStreamer.EmitInstruction(MCInstBuilder(PPC::BCTR));
749 
750       OutStreamer.SwitchSection(LSPSection);
751       OutStreamer.EmitLabel(LazyPtr);
752       OutStreamer.EmitSymbolAttribute(RawSym, MCSA_IndirectSymbol);
753 
754       MCSymbol *DyldStubBindingHelper =
755         OutContext.GetOrCreateSymbol(StringRef("dyld_stub_binding_helper"));
756       if (isPPC64) {
757         // .quad dyld_stub_binding_helper
758         OutStreamer.EmitSymbolValue(DyldStubBindingHelper, 8);
759       } else {
760         // .long dyld_stub_binding_helper
761         OutStreamer.EmitSymbolValue(DyldStubBindingHelper, 4);
762       }
763     }
764     OutStreamer.AddBlankLine();
765     return;
766   }
767 
768   const MCSection *StubSection =
769     OutContext.getMachOSection("__TEXT","__symbol_stub1",
770                                MCSectionMachO::S_SYMBOL_STUBS |
771                                MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
772                                16, SectionKind::getText());
773   for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
774     MCSymbol *Stub = Stubs[i].first;
775     MCSymbol *RawSym = Stubs[i].second.getPointer();
776     MCSymbol *LazyPtr = GetLazyPtr(Stub, OutContext);
777 
778     OutStreamer.SwitchSection(StubSection);
779     EmitAlignment(4);
780     OutStreamer.EmitLabel(Stub);
781     OutStreamer.EmitSymbolAttribute(RawSym, MCSA_IndirectSymbol);
782     // lis r11, ha16(LazyPtr)
783     const MCExpr *LazyPtrHa16 =
784       MCSymbolRefExpr::Create(LazyPtr, MCSymbolRefExpr::VK_PPC_DARWIN_HA16,
785                               OutContext);
786     OutStreamer.EmitInstruction(MCInstBuilder(PPC::LIS)
787       .addReg(PPC::R11)
788       .addExpr(LazyPtrHa16));
789 
790     const MCExpr *LazyPtrLo16 =
791       MCSymbolRefExpr::Create(LazyPtr, MCSymbolRefExpr::VK_PPC_DARWIN_LO16,
792                               OutContext);
793     // ldu r12, lo16(LazyPtr)(r11)
794     // lwzu r12, lo16(LazyPtr)(r11)
795     OutStreamer.EmitInstruction(MCInstBuilder(isPPC64 ? PPC::LDU : PPC::LWZU)
796       .addReg(PPC::R12)
797       .addExpr(LazyPtrLo16).addExpr(LazyPtrLo16)
798       .addReg(PPC::R11));
799 
800     // mtctr r12
801     OutStreamer.EmitInstruction(MCInstBuilder(PPC::MTCTR).addReg(PPC::R12));
802     // bctr
803     OutStreamer.EmitInstruction(MCInstBuilder(PPC::BCTR));
804 
805     OutStreamer.SwitchSection(LSPSection);
806     OutStreamer.EmitLabel(LazyPtr);
807     OutStreamer.EmitSymbolAttribute(RawSym, MCSA_IndirectSymbol);
808 
809     MCSymbol *DyldStubBindingHelper =
810       OutContext.GetOrCreateSymbol(StringRef("dyld_stub_binding_helper"));
811     if (isPPC64) {
812       // .quad dyld_stub_binding_helper
813       OutStreamer.EmitSymbolValue(DyldStubBindingHelper, 8);
814     } else {
815       // .long dyld_stub_binding_helper
816       OutStreamer.EmitSymbolValue(DyldStubBindingHelper, 4);
817     }
818   }
819 
820   OutStreamer.AddBlankLine();
821 }
822 
823 
824 bool PPCDarwinAsmPrinter::doFinalization(Module &M) {
825   bool isPPC64 = TM.getDataLayout()->getPointerSizeInBits() == 64;
826 
827   // Darwin/PPC always uses mach-o.
828   const TargetLoweringObjectFileMachO &TLOFMacho =
829     static_cast<const TargetLoweringObjectFileMachO &>(getObjFileLowering());
830   MachineModuleInfoMachO &MMIMacho =
831     MMI->getObjFileInfo<MachineModuleInfoMachO>();
832 
833   MachineModuleInfoMachO::SymbolListTy Stubs = MMIMacho.GetFnStubList();
834   if (!Stubs.empty())
835     EmitFunctionStubs(Stubs);
836 
837   if (MAI->doesSupportExceptionHandling() && MMI) {
838     // Add the (possibly multiple) personalities to the set of global values.
839     // Only referenced functions get into the Personalities list.
840     const std::vector<const Function*> &Personalities = MMI->getPersonalities();
841     for (std::vector<const Function*>::const_iterator I = Personalities.begin(),
842          E = Personalities.end(); I != E; ++I) {
843       if (*I) {
844         MCSymbol *NLPSym = GetSymbolWithGlobalValueBase(*I, "$non_lazy_ptr");
845         MachineModuleInfoImpl::StubValueTy &StubSym =
846           MMIMacho.getGVStubEntry(NLPSym);
847         StubSym = MachineModuleInfoImpl::StubValueTy(Mang->getSymbol(*I), true);
848       }
849     }
850   }
851 
852   // Output stubs for dynamically-linked functions.
853   Stubs = MMIMacho.GetGVStubList();
854 
855   // Output macho stubs for external and common global variables.
856   if (!Stubs.empty()) {
857     // Switch with ".non_lazy_symbol_pointer" directive.
858     OutStreamer.SwitchSection(TLOFMacho.getNonLazySymbolPointerSection());
859     EmitAlignment(isPPC64 ? 3 : 2);
860 
861     for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
862       // L_foo$stub:
863       OutStreamer.EmitLabel(Stubs[i].first);
864       //   .indirect_symbol _foo
865       MachineModuleInfoImpl::StubValueTy &MCSym = Stubs[i].second;
866       OutStreamer.EmitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
867 
868       if (MCSym.getInt())
869         // External to current translation unit.
870         OutStreamer.EmitIntValue(0, isPPC64 ? 8 : 4/*size*/, 0/*addrspace*/);
871       else
872         // Internal to current translation unit.
873         //
874         // When we place the LSDA into the TEXT section, the type info pointers
875         // need to be indirect and pc-rel. We accomplish this by using NLPs.
876         // However, sometimes the types are local to the file. So we need to
877         // fill in the value for the NLP in those cases.
878         OutStreamer.EmitValue(MCSymbolRefExpr::Create(MCSym.getPointer(),
879                                                       OutContext),
880                               isPPC64 ? 8 : 4/*size*/, 0/*addrspace*/);
881     }
882 
883     Stubs.clear();
884     OutStreamer.AddBlankLine();
885   }
886 
887   Stubs = MMIMacho.GetHiddenGVStubList();
888   if (!Stubs.empty()) {
889     OutStreamer.SwitchSection(getObjFileLowering().getDataSection());
890     EmitAlignment(isPPC64 ? 3 : 2);
891 
892     for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
893       // L_foo$stub:
894       OutStreamer.EmitLabel(Stubs[i].first);
895       //   .long _foo
896       OutStreamer.EmitValue(MCSymbolRefExpr::
897                             Create(Stubs[i].second.getPointer(),
898                                    OutContext),
899                             isPPC64 ? 8 : 4/*size*/, 0/*addrspace*/);
900     }
901 
902     Stubs.clear();
903     OutStreamer.AddBlankLine();
904   }
905 
906   // Funny Darwin hack: This flag tells the linker that no global symbols
907   // contain code that falls through to other global symbols (e.g. the obvious
908   // implementation of multiple entry points).  If this doesn't occur, the
909   // linker can safely perform dead code stripping.  Since LLVM never generates
910   // code that does this, it is always safe to set.
911   OutStreamer.EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
912 
913   return AsmPrinter::doFinalization(M);
914 }
915 
916 /// createPPCAsmPrinterPass - Returns a pass that prints the PPC assembly code
917 /// for a MachineFunction to the given output stream, in a format that the
918 /// Darwin assembler can deal with.
919 ///
920 static AsmPrinter *createPPCAsmPrinterPass(TargetMachine &tm,
921                                            MCStreamer &Streamer) {
922   const PPCSubtarget *Subtarget = &tm.getSubtarget<PPCSubtarget>();
923 
924   if (Subtarget->isDarwin())
925     return new PPCDarwinAsmPrinter(tm, Streamer);
926   return new PPCLinuxAsmPrinter(tm, Streamer);
927 }
928 
929 // Force static initialization.
930 extern "C" void LLVMInitializePowerPCAsmPrinter() {
931   TargetRegistry::RegisterAsmPrinter(ThePPC32Target, createPPCAsmPrinterPass);
932   TargetRegistry::RegisterAsmPrinter(ThePPC64Target, createPPCAsmPrinterPass);
933 }
934