SparcAsmPrinter.cpp revision 54799c2a516520c3f669c46439f8f6b250ac0274 
1//===-- SparcV8AsmPrinter.cpp - SparcV8 LLVM assembly writer --------------===//
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 GAS-format Sparc V8 assembly language.
12//
13//===----------------------------------------------------------------------===//
14
15#include "SparcV8.h"
16#include "SparcV8InstrInfo.h"
17#include "llvm/Constants.h"
18#include "llvm/DerivedTypes.h"
19#include "llvm/Module.h"
20#include "llvm/Assembly/Writer.h"
21#include "llvm/CodeGen/MachineFunctionPass.h"
22#include "llvm/CodeGen/MachineConstantPool.h"
23#include "llvm/CodeGen/MachineInstr.h"
24#include "llvm/Target/TargetMachine.h"
25#include "llvm/Support/Mangler.h"
26#include "llvm/ADT/Statistic.h"
27#include "llvm/ADT/StringExtras.h"
28#include "llvm/Support/CommandLine.h"
29#include <cctype>
30using namespace llvm;
31
32namespace {
33  Statistic<> EmittedInsts("asm-printer", "Number of machine instrs printed");
34
35  struct V8Printer : public MachineFunctionPass {
36    /// Output stream on which we're printing assembly code.
37    ///
38    std::ostream &O;
39
40    /// Target machine description which we query for reg. names, data
41    /// layout, etc.
42    ///
43    TargetMachine &TM;
44
45    /// Name-mangler for global names.
46    ///
47    Mangler *Mang;
48
49    V8Printer(std::ostream &o, TargetMachine &tm) : O(o), TM(tm) { }
50
51    /// We name each basic block in a Function with a unique number, so
52    /// that we can consistently refer to them later. This is cleared
53    /// at the beginning of each call to runOnMachineFunction().
54    ///
55    typedef std::map<const Value *, unsigned> ValueMapTy;
56    ValueMapTy NumberForBB;
57
58    /// Cache of mangled name for current function. This is
59    /// recalculated at the beginning of each call to
60    /// runOnMachineFunction().
61    ///
62    std::string CurrentFnName;
63
64    virtual const char *getPassName() const {
65      return "SparcV8 Assembly Printer";
66    }
67
68    void emitConstantValueOnly(const Constant *CV);
69    void emitGlobalConstant(const Constant *CV);
70    void printConstantPool(MachineConstantPool *MCP);
71    void printOperand(const MachineInstr *MI, int opNum);
72    void printBaseOffsetPair (const MachineInstr *MI, int i, bool brackets=true);
73    void printMachineInstruction(const MachineInstr *MI);
74    bool runOnMachineFunction(MachineFunction &F);
75    bool doInitialization(Module &M);
76    bool doFinalization(Module &M);
77  };
78} // end of anonymous namespace
79
80/// createSparcV8CodePrinterPass - Returns a pass that prints the SparcV8
81/// assembly code for a MachineFunction to the given output stream,
82/// using the given target machine description.  This should work
83/// regardless of whether the function is in SSA form.
84///
85FunctionPass *llvm::createSparcV8CodePrinterPass (std::ostream &o,
86                                                  TargetMachine &tm) {
87  return new V8Printer(o, tm);
88}
89
90/// toOctal - Convert the low order bits of X into an octal digit.
91///
92static inline char toOctal(int X) {
93  return (X&7)+'0';
94}
95
96/// getAsCString - Return the specified array as a C compatible
97/// string, only if the predicate isStringCompatible is true.
98///
99static void printAsCString(std::ostream &O, const ConstantArray *CVA) {
100  assert(CVA->isString() && "Array is not string compatible!");
101
102  O << "\"";
103  for (unsigned i = 0; i != CVA->getNumOperands(); ++i) {
104    unsigned char C = cast<ConstantInt>(CVA->getOperand(i))->getRawValue();
105
106    if (C == '"') {
107      O << "\\\"";
108    } else if (C == '\\') {
109      O << "\\\\";
110    } else if (isprint(C)) {
111      O << C;
112    } else {
113      switch(C) {
114      case '\b': O << "\\b"; break;
115      case '\f': O << "\\f"; break;
116      case '\n': O << "\\n"; break;
117      case '\r': O << "\\r"; break;
118      case '\t': O << "\\t"; break;
119      default:
120        O << '\\';
121        O << toOctal(C >> 6);
122        O << toOctal(C >> 3);
123        O << toOctal(C >> 0);
124        break;
125      }
126    }
127  }
128  O << "\"";
129}
130
131// Print out the specified constant, without a storage class.  Only the
132// constants valid in constant expressions can occur here.
133void V8Printer::emitConstantValueOnly(const Constant *CV) {
134  if (CV->isNullValue() || isa<UndefValue> (CV))
135    O << "0";
136  else if (const ConstantBool *CB = dyn_cast<ConstantBool>(CV)) {
137    assert(CB == ConstantBool::True);
138    O << "1";
139  } else if (const ConstantSInt *CI = dyn_cast<ConstantSInt>(CV))
140    if (((CI->getValue() << 32) >> 32) == CI->getValue())
141      O << CI->getValue();
142    else
143      O << (unsigned long long)CI->getValue();
144  else if (const ConstantUInt *CI = dyn_cast<ConstantUInt>(CV))
145    O << CI->getValue();
146  else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
147    // This is a constant address for a global variable or function.  Use the
148    // name of the variable or function as the address value.
149    O << Mang->getValueName(GV);
150  else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
151    const TargetData &TD = TM.getTargetData();
152    switch(CE->getOpcode()) {
153    case Instruction::GetElementPtr: {
154      // generate a symbolic expression for the byte address
155      const Constant *ptrVal = CE->getOperand(0);
156      std::vector<Value*> idxVec(CE->op_begin()+1, CE->op_end());
157      if (unsigned Offset = TD.getIndexedOffset(ptrVal->getType(), idxVec)) {
158        O << "(";
159        emitConstantValueOnly(ptrVal);
160        O << ") + " << Offset;
161      } else {
162        emitConstantValueOnly(ptrVal);
163      }
164      break;
165    }
166    case Instruction::Cast: {
167      // Support only non-converting or widening casts for now, that is, ones
168      // that do not involve a change in value.  This assertion is really gross,
169      // and may not even be a complete check.
170      Constant *Op = CE->getOperand(0);
171      const Type *OpTy = Op->getType(), *Ty = CE->getType();
172
173      // Pointers on ILP32 machines can be losslessly converted back and
174      // forth into 32-bit or wider integers, regardless of signedness.
175      assert(((isa<PointerType>(OpTy)
176               && (Ty == Type::LongTy || Ty == Type::ULongTy
177                   || Ty == Type::IntTy || Ty == Type::UIntTy))
178              || (isa<PointerType>(Ty)
179                  && (OpTy == Type::LongTy || OpTy == Type::ULongTy
180                      || OpTy == Type::IntTy || OpTy == Type::UIntTy))
181              || (((TD.getTypeSize(Ty) >= TD.getTypeSize(OpTy))
182                   && OpTy->isLosslesslyConvertibleTo(Ty))))
183             && "FIXME: Don't yet support this kind of constant cast expr");
184      O << "(";
185      emitConstantValueOnly(Op);
186      O << ")";
187      break;
188    }
189    case Instruction::Add:
190      O << "(";
191      emitConstantValueOnly(CE->getOperand(0));
192      O << ") + (";
193      emitConstantValueOnly(CE->getOperand(1));
194      O << ")";
195      break;
196    default:
197      assert(0 && "Unsupported operator!");
198    }
199  } else {
200    assert(0 && "Unknown constant value!");
201  }
202}
203
204// Print a constant value or values, with the appropriate storage class as a
205// prefix.
206void V8Printer::emitGlobalConstant(const Constant *CV) {
207  const TargetData &TD = TM.getTargetData();
208
209  if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) {
210    if (CVA->isString()) {
211      O << "\t.ascii\t";
212      printAsCString(O, CVA);
213      O << "\n";
214    } else { // Not a string.  Print the values in successive locations
215      for (unsigned i = 0, e = CVA->getNumOperands(); i != e; i++)
216        emitGlobalConstant(CVA->getOperand(i));
217    }
218    return;
219  } else if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) {
220    // Print the fields in successive locations. Pad to align if needed!
221    const StructLayout *cvsLayout = TD.getStructLayout(CVS->getType());
222    unsigned sizeSoFar = 0;
223    for (unsigned i = 0, e = CVS->getNumOperands(); i != e; i++) {
224      const Constant* field = CVS->getOperand(i);
225
226      // Check if padding is needed and insert one or more 0s.
227      unsigned fieldSize = TD.getTypeSize(field->getType());
228      unsigned padSize = ((i == e-1? cvsLayout->StructSize
229                           : cvsLayout->MemberOffsets[i+1])
230                          - cvsLayout->MemberOffsets[i]) - fieldSize;
231      sizeSoFar += fieldSize + padSize;
232
233      // Now print the actual field value
234      emitGlobalConstant(field);
235
236      // Insert the field padding unless it's zero bytes...
237      if (padSize)
238        O << "\t.skip\t " << padSize << "\n";
239    }
240    assert(sizeSoFar == cvsLayout->StructSize &&
241           "Layout of constant struct may be incorrect!");
242    return;
243  } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) {
244    // FP Constants are printed as integer constants to avoid losing
245    // precision...
246    double Val = CFP->getValue();
247    switch (CFP->getType()->getTypeID()) {
248    default: assert(0 && "Unknown floating point type!");
249    case Type::FloatTyID: {
250      union FU {                            // Abide by C TBAA rules
251        float FVal;
252        unsigned UVal;
253      } U;
254      U.FVal = Val;
255      O << ".long\t" << U.UVal << "\t! float " << Val << "\n";
256      return;
257    }
258    case Type::DoubleTyID: {
259      union DU {                            // Abide by C TBAA rules
260        double FVal;
261        uint64_t UVal;
262      } U;
263      U.FVal = Val;
264      O << ".word\t0x" << std::hex << (U.UVal >> 32) << std::dec << "\t! double " << Val << "\n";
265      O << ".word\t0x" << std::hex << (U.UVal & 0xffffffffUL) << std::dec << "\t! double " << Val << "\n";
266      return;
267    }
268    }
269  } else if (isa<UndefValue> (CV)) {
270    unsigned size = TD.getTypeSize (CV->getType ());
271    O << "\t.skip\t " << size << "\n";
272    return;
273  }
274
275  const Type *type = CV->getType();
276  O << "\t";
277  switch (type->getTypeID()) {
278  case Type::BoolTyID: case Type::UByteTyID: case Type::SByteTyID:
279    O << ".byte";
280    break;
281  case Type::UShortTyID: case Type::ShortTyID:
282    O << ".word";
283    break;
284  case Type::FloatTyID: case Type::PointerTyID:
285  case Type::UIntTyID: case Type::IntTyID:
286    O << ".long";
287    break;
288  case Type::DoubleTyID:
289  case Type::ULongTyID: case Type::LongTyID:
290    O << ".quad";
291    break;
292  default:
293    assert (0 && "Can't handle printing this type of thing");
294    break;
295  }
296  O << "\t";
297  emitConstantValueOnly(CV);
298  O << "\n";
299}
300
301/// printConstantPool - Print to the current output stream assembly
302/// representations of the constants in the constant pool MCP. This is
303/// used to print out constants which have been "spilled to memory" by
304/// the code generator.
305///
306void V8Printer::printConstantPool(MachineConstantPool *MCP) {
307  const std::vector<Constant*> &CP = MCP->getConstants();
308  const TargetData &TD = TM.getTargetData();
309
310  if (CP.empty()) return;
311
312  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
313    O << "\t.section \".rodata\"\n";
314    O << "\t.align " << (unsigned)TD.getTypeAlignment(CP[i]->getType())
315      << "\n";
316    O << ".CPI" << CurrentFnName << "_" << i << ":\t\t\t\t\t!"
317      << *CP[i] << "\n";
318    emitGlobalConstant(CP[i]);
319  }
320}
321
322/// runOnMachineFunction - This uses the printMachineInstruction()
323/// method to print assembly for each instruction.
324///
325bool V8Printer::runOnMachineFunction(MachineFunction &MF) {
326  // BBNumber is used here so that a given Printer will never give two
327  // BBs the same name. (If you have a better way, please let me know!)
328  static unsigned BBNumber = 0;
329
330  O << "\n\n";
331  // What's my mangled name?
332  CurrentFnName = Mang->getValueName(MF.getFunction());
333
334  // Print out constants referenced by the function
335  printConstantPool(MF.getConstantPool());
336
337  // Print out labels for the function.
338  O << "\t.text\n";
339  O << "\t.align 16\n";
340  O << "\t.globl\t" << CurrentFnName << "\n";
341  O << "\t.type\t" << CurrentFnName << ", #function\n";
342  O << CurrentFnName << ":\n";
343
344  // Number each basic block so that we can consistently refer to them
345  // in PC-relative references.
346  NumberForBB.clear();
347  for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
348       I != E; ++I) {
349    NumberForBB[I->getBasicBlock()] = BBNumber++;
350  }
351
352  // Print out code for the function.
353  for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
354       I != E; ++I) {
355    // Print a label for the basic block.
356    O << ".LBB" << Mang->getValueName(MF.getFunction ())
357      << "_" << I->getNumber () << ":\t! "
358      << I->getBasicBlock ()->getName () << "\n";
359    for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
360	 II != E; ++II) {
361      // Print the assembly for the instruction.
362      O << "\t";
363      printMachineInstruction(II);
364    }
365  }
366
367  // We didn't modify anything.
368  return false;
369}
370
371void V8Printer::printOperand(const MachineInstr *MI, int opNum) {
372  const MachineOperand &MO = MI->getOperand (opNum);
373  const MRegisterInfo &RI = *TM.getRegisterInfo();
374  bool CloseParen = false;
375  if (MI->getOpcode() == V8::SETHIi && !MO.isRegister() && !MO.isImmediate()) {
376    O << "%hi(";
377    CloseParen = true;
378  } else if (MI->getOpcode() ==V8::ORri &&!MO.isRegister() &&!MO.isImmediate())
379  {
380    O << "%lo(";
381    CloseParen = true;
382  }
383  switch (MO.getType()) {
384  case MachineOperand::MO_VirtualRegister:
385    if (Value *V = MO.getVRegValueOrNull()) {
386      O << "<" << V->getName() << ">";
387      break;
388    }
389    // FALLTHROUGH
390  case MachineOperand::MO_MachineRegister:
391    if (MRegisterInfo::isPhysicalRegister(MO.getReg()))
392      O << "%" << LowercaseString (RI.get(MO.getReg()).Name);
393    else
394      O << "%reg" << MO.getReg();
395    break;
396
397  case MachineOperand::MO_SignExtendedImmed:
398  case MachineOperand::MO_UnextendedImmed:
399    O << (int)MO.getImmedValue();
400    break;
401  case MachineOperand::MO_MachineBasicBlock: {
402    MachineBasicBlock *MBBOp = MO.getMachineBasicBlock();
403    O << ".LBB" << Mang->getValueName(MBBOp->getParent()->getFunction())
404      << "_" << MBBOp->getNumber () << "\t! "
405      << MBBOp->getBasicBlock ()->getName ();
406    return;
407  }
408  case MachineOperand::MO_PCRelativeDisp:
409    std::cerr << "Shouldn't use addPCDisp() when building SparcV8 MachineInstrs";
410    abort ();
411    return;
412  case MachineOperand::MO_GlobalAddress:
413    O << Mang->getValueName(MO.getGlobal());
414    break;
415  case MachineOperand::MO_ExternalSymbol:
416    O << MO.getSymbolName();
417    break;
418  case MachineOperand::MO_ConstantPoolIndex:
419    O << ".CPI" << CurrentFnName << "_" << MO.getConstantPoolIndex();
420    break;
421  default:
422    O << "<unknown operand type>"; abort (); break;
423  }
424  if (CloseParen) O << ")";
425}
426
427static bool isLoadInstruction (const MachineInstr *MI) {
428  switch (MI->getOpcode ()) {
429  case V8::LDSB:
430  case V8::LDSH:
431  case V8::LDUB:
432  case V8::LDUH:
433  case V8::LD:
434  case V8::LDD:
435  case V8::LDFrr:
436  case V8::LDFri:
437  case V8::LDDFrr:
438  case V8::LDDFri:
439    return true;
440  default:
441    return false;
442  }
443}
444
445static bool isStoreInstruction (const MachineInstr *MI) {
446  switch (MI->getOpcode ()) {
447  case V8::STB:
448  case V8::STH:
449  case V8::ST:
450  case V8::STD:
451  case V8::STFrr:
452  case V8::STFri:
453  case V8::STDFrr:
454  case V8::STDFri:
455    return true;
456  default:
457    return false;
458  }
459}
460
461static bool isPseudoInstruction (const MachineInstr *MI) {
462  switch (MI->getOpcode ()) {
463  case V8::PHI:
464  case V8::ADJCALLSTACKUP:
465  case V8::ADJCALLSTACKDOWN:
466  case V8::IMPLICIT_USE:
467  case V8::IMPLICIT_DEF:
468    return true;
469  default:
470    return false;
471  }
472}
473
474/// printBaseOffsetPair - Print two consecutive operands of MI, starting at #i,
475/// which form a base + offset pair (which may have brackets around it, if
476/// brackets is true, or may be in the form base - constant, if offset is a
477/// negative constant).
478///
479void V8Printer::printBaseOffsetPair (const MachineInstr *MI, int i,
480                                     bool brackets) {
481  if (brackets) O << "[";
482  printOperand (MI, i);
483  if (MI->getOperand (i + 1).isImmediate()) {
484    int Val = (int) MI->getOperand (i + 1).getImmedValue ();
485    if (Val != 0) {
486      O << ((Val >= 0) ? " + " : " - ");
487      O << ((Val >= 0) ? Val : -Val);
488    }
489  } else {
490    O << " + ";
491    printOperand (MI, i + 1);
492  }
493  if (brackets) O << "]";
494}
495
496/// printMachineInstruction -- Print out a single SparcV8 LLVM instruction
497/// MI in GAS syntax to the current output stream.
498///
499void V8Printer::printMachineInstruction(const MachineInstr *MI) {
500  unsigned Opcode = MI->getOpcode();
501  const TargetInstrInfo &TII = *TM.getInstrInfo();
502  const TargetInstrDescriptor &Desc = TII.get(Opcode);
503
504  // If it's a pseudo-instruction, comment it out.
505  if (isPseudoInstruction (MI))
506    O << "! ";
507
508  O << Desc.Name << " ";
509
510  // Printing memory instructions is a special case.
511  // for loads:  %dest = op %base, offset --> op [%base + offset], %dest
512  // for stores: op %base, offset, %src   --> op %src, [%base + offset]
513  if (isLoadInstruction (MI)) {
514    printBaseOffsetPair (MI, 1);
515    O << ", ";
516    printOperand (MI, 0);
517    O << "\n";
518    return;
519  } else if (isStoreInstruction (MI)) {
520    printOperand (MI, 2);
521    O << ", ";
522    printBaseOffsetPair (MI, 0);
523    O << "\n";
524    return;
525  } else if (Opcode == V8::JMPLrr) {
526    printBaseOffsetPair (MI, 1, false);
527    O << ", ";
528    printOperand (MI, 0);
529    O << "\n";
530    return;
531  }
532
533  // print non-immediate, non-register-def operands
534  // then print immediate operands
535  // then print register-def operands.
536  std::vector<int> print_order;
537  for (unsigned i = 0; i < MI->getNumOperands (); ++i)
538    if (!(MI->getOperand (i).isImmediate ()
539          || (MI->getOperand (i).isRegister ()
540              && MI->getOperand (i).isDef ())))
541      print_order.push_back (i);
542  for (unsigned i = 0; i < MI->getNumOperands (); ++i)
543    if (MI->getOperand (i).isImmediate ())
544      print_order.push_back (i);
545  for (unsigned i = 0; i < MI->getNumOperands (); ++i)
546    if (MI->getOperand (i).isRegister () && MI->getOperand (i).isDef ())
547      print_order.push_back (i);
548  for (unsigned i = 0, e = print_order.size (); i != e; ++i) {
549    printOperand (MI, print_order[i]);
550    if (i != (print_order.size () - 1))
551      O << ", ";
552  }
553  O << "\n";
554}
555
556bool V8Printer::doInitialization(Module &M) {
557  Mang = new Mangler(M);
558  return false; // success
559}
560
561// SwitchSection - Switch to the specified section of the executable if we are
562// not already in it!
563//
564static void SwitchSection(std::ostream &OS, std::string &CurSection,
565                          const char *NewSection) {
566  if (CurSection != NewSection) {
567    CurSection = NewSection;
568    if (!CurSection.empty())
569      OS << "\t.section \"" << NewSection << "\"\n";
570  }
571}
572
573bool V8Printer::doFinalization(Module &M) {
574  const TargetData &TD = TM.getTargetData();
575  std::string CurSection;
576
577  // Print out module-level global variables here.
578  for (Module::const_giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
579    if (I->hasInitializer()) {   // External global require no code
580      O << "\n\n";
581      std::string name = Mang->getValueName(I);
582      Constant *C = I->getInitializer();
583      unsigned Size = TD.getTypeSize(C->getType());
584      unsigned Align = TD.getTypeAlignment(C->getType());
585
586      if (C->isNullValue() &&
587          (I->hasLinkOnceLinkage() || I->hasInternalLinkage() ||
588           I->hasWeakLinkage() /* FIXME: Verify correct */)) {
589        SwitchSection(O, CurSection, ".data");
590        if (I->hasInternalLinkage())
591          O << "\t.local " << name << "\n";
592
593        O << "\t.comm " << name << "," << TD.getTypeSize(C->getType())
594          << "," << (unsigned)TD.getTypeAlignment(C->getType());
595        O << "\t\t! ";
596        WriteAsOperand(O, I, true, true, &M);
597        O << "\n";
598      } else {
599        switch (I->getLinkage()) {
600        case GlobalValue::LinkOnceLinkage:
601        case GlobalValue::WeakLinkage:   // FIXME: Verify correct for weak.
602          // Nonnull linkonce -> weak
603          O << "\t.weak " << name << "\n";
604          SwitchSection(O, CurSection, "");
605          O << "\t.section\t\".llvm.linkonce.d." << name << "\",\"aw\",@progbits\n";
606          break;
607
608        case GlobalValue::AppendingLinkage:
609          // FIXME: appending linkage variables should go into a section of
610          // their name or something.  For now, just emit them as external.
611        case GlobalValue::ExternalLinkage:
612          // If external or appending, declare as a global symbol
613          O << "\t.globl " << name << "\n";
614          // FALL THROUGH
615        case GlobalValue::InternalLinkage:
616          if (C->isNullValue())
617            SwitchSection(O, CurSection, ".bss");
618          else
619            SwitchSection(O, CurSection, ".data");
620          break;
621        }
622
623        O << "\t.align " << Align << "\n";
624        O << "\t.type " << name << ",#object\n";
625        O << "\t.size " << name << "," << Size << "\n";
626        O << name << ":\t\t\t\t! ";
627        WriteAsOperand(O, I, true, true, &M);
628        O << " = ";
629        WriteAsOperand(O, C, false, false, &M);
630        O << "\n";
631        emitGlobalConstant(C);
632      }
633    }
634
635  delete Mang;
636  return false; // success
637}
638