PPCAsmPrinter.cpp revision 9382e29c1ebc6524618b173ed04bc25295d02c6e 
1//===-- PPCAsmPrinter.cpp - Print machine instrs to PowerPC assembly --------=//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source 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 "PPCPredicates.h"
22#include "PPCTargetMachine.h"
23#include "PPCSubtarget.h"
24#include "llvm/Constants.h"
25#include "llvm/DerivedTypes.h"
26#include "llvm/Module.h"
27#include "llvm/Assembly/Writer.h"
28#include "llvm/CodeGen/AsmPrinter.h"
29#include "llvm/CodeGen/DwarfWriter.h"
30#include "llvm/CodeGen/MachineDebugInfo.h"
31#include "llvm/CodeGen/MachineFunctionPass.h"
32#include "llvm/CodeGen/MachineInstr.h"
33#include "llvm/Support/Mangler.h"
34#include "llvm/Support/MathExtras.h"
35#include "llvm/Support/CommandLine.h"
36#include "llvm/Support/Debug.h"
37#include "llvm/Support/Compiler.h"
38#include "llvm/Target/TargetAsmInfo.h"
39#include "llvm/Target/MRegisterInfo.h"
40#include "llvm/Target/TargetInstrInfo.h"
41#include "llvm/Target/TargetOptions.h"
42#include "llvm/ADT/Statistic.h"
43#include "llvm/ADT/StringExtras.h"
44#include <iostream>
45#include <set>
46using namespace llvm;
47
48namespace {
49  Statistic<> EmittedInsts("asm-printer", "Number of machine instrs printed");
50
51  struct VISIBILITY_HIDDEN PPCAsmPrinter : public AsmPrinter {
52    std::set<std::string> FnStubs, GVStubs;
53    const PPCSubtarget &Subtarget;
54
55    // Necessary for external weak linkage support
56    std::set<std::string> ExtWeakSymbols;
57
58    PPCAsmPrinter(std::ostream &O, TargetMachine &TM, const TargetAsmInfo *T)
59      : AsmPrinter(O, TM, T), Subtarget(TM.getSubtarget<PPCSubtarget>()) {
60    }
61
62    virtual const char *getPassName() const {
63      return "PowerPC Assembly Printer";
64    }
65
66    PPCTargetMachine &getTM() {
67      return static_cast<PPCTargetMachine&>(TM);
68    }
69
70    unsigned enumRegToMachineReg(unsigned enumReg) {
71      switch (enumReg) {
72      default: assert(0 && "Unhandled register!"); break;
73      case PPC::CR0:  return  0;
74      case PPC::CR1:  return  1;
75      case PPC::CR2:  return  2;
76      case PPC::CR3:  return  3;
77      case PPC::CR4:  return  4;
78      case PPC::CR5:  return  5;
79      case PPC::CR6:  return  6;
80      case PPC::CR7:  return  7;
81      }
82      abort();
83    }
84
85    /// printInstruction - This method is automatically generated by tablegen
86    /// from the instruction set description.  This method returns true if the
87    /// machine instruction was sufficiently described to print it, otherwise it
88    /// returns false.
89    bool printInstruction(const MachineInstr *MI);
90
91    void printMachineInstruction(const MachineInstr *MI);
92    void printOp(const MachineOperand &MO);
93
94    void printOperand(const MachineInstr *MI, unsigned OpNo) {
95      const MachineOperand &MO = MI->getOperand(OpNo);
96      if (MO.isRegister()) {
97        assert(MRegisterInfo::isPhysicalRegister(MO.getReg())&&"Not physreg??");
98        O << TM.getRegisterInfo()->get(MO.getReg()).Name;
99      } else if (MO.isImmediate()) {
100        O << MO.getImmedValue();
101      } else {
102        printOp(MO);
103      }
104    }
105
106    bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
107                         unsigned AsmVariant, const char *ExtraCode);
108    bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
109                               unsigned AsmVariant, const char *ExtraCode);
110
111
112    void printS5ImmOperand(const MachineInstr *MI, unsigned OpNo) {
113      char value = MI->getOperand(OpNo).getImmedValue();
114      value = (value << (32-5)) >> (32-5);
115      O << (int)value;
116    }
117    void printU5ImmOperand(const MachineInstr *MI, unsigned OpNo) {
118      unsigned char value = MI->getOperand(OpNo).getImmedValue();
119      assert(value <= 31 && "Invalid u5imm argument!");
120      O << (unsigned int)value;
121    }
122    void printU6ImmOperand(const MachineInstr *MI, unsigned OpNo) {
123      unsigned char value = MI->getOperand(OpNo).getImmedValue();
124      assert(value <= 63 && "Invalid u6imm argument!");
125      O << (unsigned int)value;
126    }
127    void printS16ImmOperand(const MachineInstr *MI, unsigned OpNo) {
128      O << (short)MI->getOperand(OpNo).getImmedValue();
129    }
130    void printU16ImmOperand(const MachineInstr *MI, unsigned OpNo) {
131      O << (unsigned short)MI->getOperand(OpNo).getImmedValue();
132    }
133    void printS16X4ImmOperand(const MachineInstr *MI, unsigned OpNo) {
134      if (MI->getOperand(OpNo).isImmediate()) {
135        O << (short)(MI->getOperand(OpNo).getImmedValue()*4);
136      } else {
137        O << "lo16(";
138        printOp(MI->getOperand(OpNo));
139        if (TM.getRelocationModel() == Reloc::PIC_)
140          O << "-\"L" << getFunctionNumber() << "$pb\")";
141        else
142          O << ')';
143      }
144    }
145    void printBranchOperand(const MachineInstr *MI, unsigned OpNo) {
146      // Branches can take an immediate operand.  This is used by the branch
147      // selection pass to print $+8, an eight byte displacement from the PC.
148      if (MI->getOperand(OpNo).isImmediate()) {
149        O << "$+" << MI->getOperand(OpNo).getImmedValue()*4;
150      } else {
151        printOp(MI->getOperand(OpNo));
152      }
153    }
154    void printCallOperand(const MachineInstr *MI, unsigned OpNo) {
155      const MachineOperand &MO = MI->getOperand(OpNo);
156      if (TM.getRelocationModel() != Reloc::Static) {
157        if (MO.getType() == MachineOperand::MO_GlobalAddress) {
158          GlobalValue *GV = MO.getGlobal();
159          if (((GV->isExternal() || GV->hasWeakLinkage() ||
160                GV->hasLinkOnceLinkage()))) {
161            // Dynamically-resolved functions need a stub for the function.
162            std::string Name = Mang->getValueName(GV);
163            FnStubs.insert(Name);
164            O << "L" << Name << "$stub";
165            if (GV->hasExternalWeakLinkage())
166              ExtWeakSymbols.insert(Name);
167            return;
168          }
169        }
170        if (MO.getType() == MachineOperand::MO_ExternalSymbol) {
171          std::string Name(TAI->getGlobalPrefix()); Name += MO.getSymbolName();
172          FnStubs.insert(Name);
173          O << "L" << Name << "$stub";
174          return;
175        }
176      }
177
178      printOp(MI->getOperand(OpNo));
179    }
180    void printAbsAddrOperand(const MachineInstr *MI, unsigned OpNo) {
181     O << (int)MI->getOperand(OpNo).getImmedValue()*4;
182    }
183    void printPICLabel(const MachineInstr *MI, unsigned OpNo) {
184      O << "\"L" << getFunctionNumber() << "$pb\"\n";
185      O << "\"L" << getFunctionNumber() << "$pb\":";
186    }
187    void printSymbolHi(const MachineInstr *MI, unsigned OpNo) {
188      if (MI->getOperand(OpNo).isImmediate()) {
189        printS16ImmOperand(MI, OpNo);
190      } else {
191        O << "ha16(";
192        printOp(MI->getOperand(OpNo));
193        if (TM.getRelocationModel() == Reloc::PIC_)
194          O << "-\"L" << getFunctionNumber() << "$pb\")";
195        else
196          O << ')';
197      }
198    }
199    void printSymbolLo(const MachineInstr *MI, unsigned OpNo) {
200      if (MI->getOperand(OpNo).isImmediate()) {
201        printS16ImmOperand(MI, OpNo);
202      } else {
203        O << "lo16(";
204        printOp(MI->getOperand(OpNo));
205        if (TM.getRelocationModel() == Reloc::PIC_)
206          O << "-\"L" << getFunctionNumber() << "$pb\")";
207        else
208          O << ')';
209      }
210    }
211    void printcrbitm(const MachineInstr *MI, unsigned OpNo) {
212      unsigned CCReg = MI->getOperand(OpNo).getReg();
213      unsigned RegNo = enumRegToMachineReg(CCReg);
214      O << (0x80 >> RegNo);
215    }
216    // The new addressing mode printers.
217    void printMemRegImm(const MachineInstr *MI, unsigned OpNo) {
218      printSymbolLo(MI, OpNo);
219      O << '(';
220      if (MI->getOperand(OpNo+1).isRegister() &&
221          MI->getOperand(OpNo+1).getReg() == PPC::R0)
222        O << "0";
223      else
224        printOperand(MI, OpNo+1);
225      O << ')';
226    }
227    void printMemRegImmShifted(const MachineInstr *MI, unsigned OpNo) {
228      if (MI->getOperand(OpNo).isImmediate())
229        printS16X4ImmOperand(MI, OpNo);
230      else
231        printSymbolLo(MI, OpNo);
232      O << '(';
233      if (MI->getOperand(OpNo+1).isRegister() &&
234          MI->getOperand(OpNo+1).getReg() == PPC::R0)
235        O << "0";
236      else
237        printOperand(MI, OpNo+1);
238      O << ')';
239    }
240
241    void printMemRegReg(const MachineInstr *MI, unsigned OpNo) {
242      // When used as the base register, r0 reads constant zero rather than
243      // the value contained in the register.  For this reason, the darwin
244      // assembler requires that we print r0 as 0 (no r) when used as the base.
245      const MachineOperand &MO = MI->getOperand(OpNo);
246      if (MO.getReg() == PPC::R0)
247        O << '0';
248      else
249        O << TM.getRegisterInfo()->get(MO.getReg()).Name;
250      O << ", ";
251      printOperand(MI, OpNo+1);
252    }
253
254    void printPredicateOperand(const MachineInstr *MI, unsigned OpNo,
255                               const char *Modifier);
256
257    virtual bool runOnMachineFunction(MachineFunction &F) = 0;
258    virtual bool doFinalization(Module &M) = 0;
259  };
260
261  /// DarwinAsmPrinter - PowerPC assembly printer, customized for Darwin/Mac OS
262  /// X
263  struct VISIBILITY_HIDDEN DarwinAsmPrinter : public PPCAsmPrinter {
264
265    DwarfWriter DW;
266
267    DarwinAsmPrinter(std::ostream &O, PPCTargetMachine &TM,
268                     const TargetAsmInfo *T)
269      : PPCAsmPrinter(O, TM, T), DW(O, this, T) {
270    }
271
272    virtual const char *getPassName() const {
273      return "Darwin PPC Assembly Printer";
274    }
275
276    bool runOnMachineFunction(MachineFunction &F);
277    bool doInitialization(Module &M);
278    bool doFinalization(Module &M);
279
280    void getAnalysisUsage(AnalysisUsage &AU) const {
281      AU.setPreservesAll();
282      AU.addRequired<MachineDebugInfo>();
283      PPCAsmPrinter::getAnalysisUsage(AU);
284    }
285
286    /// getSectionForFunction - Return the section that we should emit the
287    /// specified function body into.
288    virtual std::string getSectionForFunction(const Function &F) const;
289  };
290} // end of anonymous namespace
291
292// Include the auto-generated portion of the assembly writer
293#include "PPCGenAsmWriter.inc"
294
295void PPCAsmPrinter::printOp(const MachineOperand &MO) {
296  switch (MO.getType()) {
297  case MachineOperand::MO_Immediate:
298    std::cerr << "printOp() does not handle immediate values\n";
299    abort();
300    return;
301
302  case MachineOperand::MO_MachineBasicBlock:
303    printBasicBlockLabel(MO.getMachineBasicBlock());
304    return;
305  case MachineOperand::MO_JumpTableIndex:
306    O << TAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
307      << '_' << MO.getJumpTableIndex();
308    // FIXME: PIC relocation model
309    return;
310  case MachineOperand::MO_ConstantPoolIndex:
311    O << TAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber()
312      << '_' << MO.getConstantPoolIndex();
313    return;
314  case MachineOperand::MO_ExternalSymbol:
315    // Computing the address of an external symbol, not calling it.
316    if (TM.getRelocationModel() != Reloc::Static) {
317      std::string Name(TAI->getGlobalPrefix()); Name += MO.getSymbolName();
318      GVStubs.insert(Name);
319      O << "L" << Name << "$non_lazy_ptr";
320      return;
321    }
322    O << TAI->getGlobalPrefix() << MO.getSymbolName();
323    return;
324  case MachineOperand::MO_GlobalAddress: {
325    // Computing the address of a global symbol, not calling it.
326    GlobalValue *GV = MO.getGlobal();
327    std::string Name = Mang->getValueName(GV);
328
329    // External or weakly linked global variables need non-lazily-resolved stubs
330    if (TM.getRelocationModel() != Reloc::Static) {
331      if (((GV->isExternal() || GV->hasWeakLinkage() ||
332            GV->hasLinkOnceLinkage()))) {
333        GVStubs.insert(Name);
334        O << "L" << Name << "$non_lazy_ptr";
335        return;
336      }
337    }
338    O << Name;
339
340    if (GV->hasExternalWeakLinkage())
341      ExtWeakSymbols.insert(Name);
342    return;
343  }
344
345  default:
346    O << "<unknown operand type: " << MO.getType() << ">";
347    return;
348  }
349}
350
351/// PrintAsmOperand - Print out an operand for an inline asm expression.
352///
353bool PPCAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
354                                    unsigned AsmVariant,
355                                    const char *ExtraCode) {
356  // Does this asm operand have a single letter operand modifier?
357  if (ExtraCode && ExtraCode[0]) {
358    if (ExtraCode[1] != 0) return true; // Unknown modifier.
359
360    switch (ExtraCode[0]) {
361    default: return true;  // Unknown modifier.
362    case 'L': // Write second word of DImode reference.
363      // Verify that this operand has two consecutive registers.
364      if (!MI->getOperand(OpNo).isRegister() ||
365          OpNo+1 == MI->getNumOperands() ||
366          !MI->getOperand(OpNo+1).isRegister())
367        return true;
368      ++OpNo;   // Return the high-part.
369      break;
370    }
371  }
372
373  printOperand(MI, OpNo);
374  return false;
375}
376
377bool PPCAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
378                                          unsigned AsmVariant,
379                                          const char *ExtraCode) {
380  if (ExtraCode && ExtraCode[0])
381    return true; // Unknown modifier.
382  printMemRegReg(MI, OpNo);
383  return false;
384}
385
386void PPCAsmPrinter::printPredicateOperand(const MachineInstr *MI, unsigned OpNo,
387                                          const char *Modifier) {
388  assert(Modifier && "Must specify 'cc' or 'reg' as predicate op modifier!");
389  unsigned Code = MI->getOperand(OpNo).getImm();
390  if (!strcmp(Modifier, "cc")) {
391    switch ((PPC::Predicate)Code) {
392    case PPC::PRED_ALWAYS: return; // Don't print anything for always.
393    case PPC::PRED_LT: O << "lt"; return;
394    case PPC::PRED_LE: O << "le"; return;
395    case PPC::PRED_EQ: O << "eq"; return;
396    case PPC::PRED_GE: O << "ge"; return;
397    case PPC::PRED_GT: O << "gt"; return;
398    case PPC::PRED_NE: O << "ne"; return;
399    case PPC::PRED_UN: O << "un"; return;
400    case PPC::PRED_NU: O << "nu"; return;
401    }
402
403  } else {
404    assert(!strcmp(Modifier, "reg") &&
405           "Need to specify 'cc' or 'reg' as predicate op modifier!");
406    // Don't print the register for 'always'.
407    if (Code == PPC::PRED_ALWAYS) return;
408    printOperand(MI, OpNo+1);
409  }
410}
411
412
413/// printMachineInstruction -- Print out a single PowerPC MI in Darwin syntax to
414/// the current output stream.
415///
416void PPCAsmPrinter::printMachineInstruction(const MachineInstr *MI) {
417  ++EmittedInsts;
418
419  // Check for slwi/srwi mnemonics.
420  if (MI->getOpcode() == PPC::RLWINM) {
421    bool FoundMnemonic = false;
422    unsigned char SH = MI->getOperand(2).getImmedValue();
423    unsigned char MB = MI->getOperand(3).getImmedValue();
424    unsigned char ME = MI->getOperand(4).getImmedValue();
425    if (SH <= 31 && MB == 0 && ME == (31-SH)) {
426      O << "slwi "; FoundMnemonic = true;
427    }
428    if (SH <= 31 && MB == (32-SH) && ME == 31) {
429      O << "srwi "; FoundMnemonic = true;
430      SH = 32-SH;
431    }
432    if (FoundMnemonic) {
433      printOperand(MI, 0);
434      O << ", ";
435      printOperand(MI, 1);
436      O << ", " << (unsigned int)SH << "\n";
437      return;
438    }
439  } else if (MI->getOpcode() == PPC::OR || MI->getOpcode() == PPC::OR8) {
440    if (MI->getOperand(1).getReg() == MI->getOperand(2).getReg()) {
441      O << "mr ";
442      printOperand(MI, 0);
443      O << ", ";
444      printOperand(MI, 1);
445      O << "\n";
446      return;
447    }
448  } else if (MI->getOpcode() == PPC::RLDICR) {
449    unsigned char SH = MI->getOperand(2).getImmedValue();
450    unsigned char ME = MI->getOperand(3).getImmedValue();
451    // rldicr RA, RS, SH, 63-SH == sldi RA, RS, SH
452    if (63-SH == ME) {
453      O << "sldi ";
454      printOperand(MI, 0);
455      O << ", ";
456      printOperand(MI, 1);
457      O << ", " << (unsigned int)SH << "\n";
458      return;
459    }
460  }
461
462  if (printInstruction(MI))
463    return; // Printer was automatically generated
464
465  assert(0 && "Unhandled instruction in asm writer!");
466  abort();
467  return;
468}
469
470
471
472std::string DarwinAsmPrinter::getSectionForFunction(const Function &F) const {
473  switch (F.getLinkage()) {
474  default: assert(0 && "Unknown linkage type!");
475  case Function::ExternalLinkage:
476  case Function::InternalLinkage: return TAI->getTextSection();
477  case Function::WeakLinkage:
478  case Function::LinkOnceLinkage:
479    return ".section __TEXT,__textcoal_nt,coalesced,pure_instructions";
480  }
481}
482
483/// runOnMachineFunction - This uses the printMachineInstruction()
484/// method to print assembly for each instruction.
485///
486bool DarwinAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
487  DW.SetDebugInfo(&getAnalysis<MachineDebugInfo>());
488
489  SetupMachineFunction(MF);
490  O << "\n\n";
491
492  // Print out constants referenced by the function
493  EmitConstantPool(MF.getConstantPool());
494
495  // Print out labels for the function.
496  const Function *F = MF.getFunction();
497  SwitchToTextSection(getSectionForFunction(*F).c_str(), F);
498
499  switch (F->getLinkage()) {
500  default: assert(0 && "Unknown linkage type!");
501  case Function::InternalLinkage:  // Symbols default to internal.
502    break;
503  case Function::ExternalLinkage:
504    O << "\t.globl\t" << CurrentFnName << "\n";
505    break;
506  case Function::WeakLinkage:
507  case Function::LinkOnceLinkage:
508    O << "\t.globl\t" << CurrentFnName << "\n";
509    O << "\t.weak_definition\t" << CurrentFnName << "\n";
510    break;
511  }
512  EmitAlignment(4, F);
513  O << CurrentFnName << ":\n";
514
515  // Emit pre-function debug information.
516  DW.BeginFunction(&MF);
517
518  // Print out code for the function.
519  for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
520       I != E; ++I) {
521    // Print a label for the basic block.
522    if (I != MF.begin()) {
523      printBasicBlockLabel(I, true);
524      O << '\n';
525    }
526    for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
527         II != E; ++II) {
528      // Print the assembly for the instruction.
529      O << "\t";
530      printMachineInstruction(II);
531    }
532  }
533
534  // Print out jump tables referenced by the function.
535  EmitJumpTableInfo(MF.getJumpTableInfo(), MF);
536
537  // Emit post-function debug information.
538  DW.EndFunction();
539
540  // We didn't modify anything.
541  return false;
542}
543
544
545bool DarwinAsmPrinter::doInitialization(Module &M) {
546  if (Subtarget.isGigaProcessor())
547    O << "\t.machine ppc970\n";
548  AsmPrinter::doInitialization(M);
549
550  // Darwin wants symbols to be quoted if they have complex names.
551  Mang->setUseQuotes(true);
552
553  // Prime text sections so they are adjacent.  This reduces the likelihood a
554  // large data or debug section causes a branch to exceed 16M limit.
555  SwitchToTextSection(".section __TEXT,__textcoal_nt,coalesced,"
556                      "pure_instructions");
557  if (TM.getRelocationModel() == Reloc::PIC_) {
558    SwitchToTextSection(".section __TEXT,__picsymbolstub1,symbol_stubs,"
559                          "pure_instructions,32");
560  } else if (TM.getRelocationModel() == Reloc::DynamicNoPIC) {
561    SwitchToTextSection(".section __TEXT,__symbol_stub1,symbol_stubs,"
562                        "pure_instructions,16");
563  }
564  SwitchToTextSection(TAI->getTextSection());
565
566  // Emit initial debug information.
567  DW.BeginModule(&M);
568  return false;
569}
570
571bool DarwinAsmPrinter::doFinalization(Module &M) {
572  const TargetData *TD = TM.getTargetData();
573
574  // Print out module-level global variables here.
575  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
576       I != E; ++I) {
577    if (!I->hasInitializer()) continue;   // External global require no code
578
579    // Check to see if this is a special global used by LLVM, if so, emit it.
580    if (EmitSpecialLLVMGlobal(I))
581      continue;
582
583    std::string name = Mang->getValueName(I);
584    Constant *C = I->getInitializer();
585    unsigned Size = TD->getTypeSize(C->getType());
586    unsigned Align = TD->getPreferredAlignmentLog(I);
587
588    if (C->isNullValue() && /* FIXME: Verify correct */
589        (I->hasInternalLinkage() || I->hasWeakLinkage() ||
590         I->hasLinkOnceLinkage() ||
591         (I->hasExternalLinkage() && !I->hasSection()))) {
592      if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
593      if (I->hasExternalLinkage()) {
594        O << "\t.globl " << name << '\n';
595        O << "\t.zerofill __DATA, __common, " << name << ", "
596          << Size << ", " << Align;
597      } else if (I->hasInternalLinkage()) {
598        SwitchToDataSection("\t.data", I);
599        O << TAI->getLCOMMDirective() << name << "," << Size << "," << Align;
600      } else {
601        SwitchToDataSection("\t.data", I);
602        O << ".comm " << name << "," << Size;
603      }
604      O << "\t\t; '" << I->getName() << "'\n";
605    } else {
606      switch (I->getLinkage()) {
607      case GlobalValue::LinkOnceLinkage:
608      case GlobalValue::WeakLinkage:
609        O << "\t.globl " << name << '\n'
610          << "\t.weak_definition " << name << '\n';
611        SwitchToDataSection(".section __DATA,__datacoal_nt,coalesced", I);
612        break;
613      case GlobalValue::AppendingLinkage:
614        // FIXME: appending linkage variables should go into a section of
615        // their name or something.  For now, just emit them as external.
616      case GlobalValue::ExternalLinkage:
617        // If external or appending, declare as a global symbol
618        O << "\t.globl " << name << "\n";
619        // FALL THROUGH
620      case GlobalValue::InternalLinkage:
621        if (I->isConstant()) {
622          const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
623          if (TAI->getCStringSection() && CVA && CVA->isCString()) {
624            SwitchToDataSection(TAI->getCStringSection(), I);
625            break;
626          }
627        }
628
629        SwitchToDataSection("\t.data", I);
630        break;
631      default:
632        std::cerr << "Unknown linkage type!";
633        abort();
634      }
635
636      EmitAlignment(Align, I);
637      O << name << ":\t\t\t\t; '" << I->getName() << "'\n";
638
639      // If the initializer is a extern weak symbol, remember to emit the weak
640      // reference!
641      if (const GlobalValue *GV = dyn_cast<GlobalValue>(C))
642        if (GV->hasExternalWeakLinkage())
643          ExtWeakSymbols.insert(Mang->getValueName(GV));
644
645      EmitGlobalConstant(C);
646      O << '\n';
647    }
648  }
649
650  if (ExtWeakSymbols.begin() != ExtWeakSymbols.end())
651    SwitchToDataSection("");
652  for (std::set<std::string>::iterator i = ExtWeakSymbols.begin(),
653       e = ExtWeakSymbols.end(); i != e; ++i) {
654    O << "\t.weak_reference " << *i << "\n";
655  }
656
657  bool isPPC64 = TD->getPointerSizeInBits() == 64;
658
659  // Output stubs for dynamically-linked functions
660  if (TM.getRelocationModel() == Reloc::PIC_) {
661    for (std::set<std::string>::iterator i = FnStubs.begin(), e = FnStubs.end();
662         i != e; ++i) {
663      SwitchToTextSection(".section __TEXT,__picsymbolstub1,symbol_stubs,"
664                          "pure_instructions,32");
665      EmitAlignment(4);
666      O << "L" << *i << "$stub:\n";
667      O << "\t.indirect_symbol " << *i << "\n";
668      O << "\tmflr r0\n";
669      O << "\tbcl 20,31,L0$" << *i << "\n";
670      O << "L0$" << *i << ":\n";
671      O << "\tmflr r11\n";
672      O << "\taddis r11,r11,ha16(L" << *i << "$lazy_ptr-L0$" << *i << ")\n";
673      O << "\tmtlr r0\n";
674      if (isPPC64)
675        O << "\tldu r12,lo16(L" << *i << "$lazy_ptr-L0$" << *i << ")(r11)\n";
676      else
677        O << "\tlwzu r12,lo16(L" << *i << "$lazy_ptr-L0$" << *i << ")(r11)\n";
678      O << "\tmtctr r12\n";
679      O << "\tbctr\n";
680      SwitchToDataSection(".lazy_symbol_pointer");
681      O << "L" << *i << "$lazy_ptr:\n";
682      O << "\t.indirect_symbol " << *i << "\n";
683      if (isPPC64)
684        O << "\t.quad dyld_stub_binding_helper\n";
685      else
686        O << "\t.long dyld_stub_binding_helper\n";
687    }
688  } else {
689    for (std::set<std::string>::iterator i = FnStubs.begin(), e = FnStubs.end();
690         i != e; ++i) {
691      SwitchToTextSection(".section __TEXT,__symbol_stub1,symbol_stubs,"
692                          "pure_instructions,16");
693      EmitAlignment(4);
694      O << "L" << *i << "$stub:\n";
695      O << "\t.indirect_symbol " << *i << "\n";
696      O << "\tlis r11,ha16(L" << *i << "$lazy_ptr)\n";
697      if (isPPC64)
698        O << "\tldu r12,lo16(L" << *i << "$lazy_ptr)(r11)\n";
699      else
700        O << "\tlwzu r12,lo16(L" << *i << "$lazy_ptr)(r11)\n";
701      O << "\tmtctr r12\n";
702      O << "\tbctr\n";
703      SwitchToDataSection(".lazy_symbol_pointer");
704      O << "L" << *i << "$lazy_ptr:\n";
705      O << "\t.indirect_symbol " << *i << "\n";
706      if (isPPC64)
707        O << "\t.quad dyld_stub_binding_helper\n";
708      else
709        O << "\t.long dyld_stub_binding_helper\n";
710    }
711  }
712
713  O << "\n";
714
715  // Output stubs for external and common global variables.
716  if (GVStubs.begin() != GVStubs.end()) {
717    SwitchToDataSection(".non_lazy_symbol_pointer");
718    for (std::set<std::string>::iterator I = GVStubs.begin(),
719         E = GVStubs.end(); I != E; ++I) {
720      O << "L" << *I << "$non_lazy_ptr:\n";
721      O << "\t.indirect_symbol " << *I << "\n";
722      if (isPPC64)
723        O << "\t.quad\t0\n";
724      else
725        O << "\t.long\t0\n";
726
727    }
728  }
729
730  // Emit initial debug information.
731  DW.EndModule();
732
733  // Funny Darwin hack: This flag tells the linker that no global symbols
734  // contain code that falls through to other global symbols (e.g. the obvious
735  // implementation of multiple entry points).  If this doesn't occur, the
736  // linker can safely perform dead code stripping.  Since LLVM never generates
737  // code that does this, it is always safe to set.
738  O << "\t.subsections_via_symbols\n";
739
740  AsmPrinter::doFinalization(M);
741  return false; // success
742}
743
744
745
746/// createDarwinCodePrinterPass - Returns a pass that prints the PPC assembly
747/// code for a MachineFunction to the given output stream, in a format that the
748/// Darwin assembler can deal with.
749///
750FunctionPass *llvm::createPPCAsmPrinterPass(std::ostream &o,
751                                            PPCTargetMachine &tm) {
752  return new DarwinAsmPrinter(o, tm, tm.getTargetAsmInfo());
753}
754
755