SparcAsmPrinter.cpp revision b8df7c22131368abd3e7d6e0e4b0fc6ee74f8427 
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 "llvm/Support/MathExtras.h"
30#include <cctype>
31using namespace llvm;
32
33namespace {
34  Statistic<> EmittedInsts("asm-printer", "Number of machine instrs printed");
35
36  struct V8Printer : public MachineFunctionPass {
37    /// Output stream on which we're printing assembly code.
38    ///
39    std::ostream &O;
40
41    /// Target machine description which we query for reg. names, data
42    /// layout, etc.
43    ///
44    TargetMachine &TM;
45
46    /// Name-mangler for global names.
47    ///
48    Mangler *Mang;
49
50    V8Printer(std::ostream &o, TargetMachine &tm) : O(o), TM(tm) { }
51
52    /// We name each basic block in a Function with a unique number, so
53    /// that we can consistently refer to them later. This is cleared
54    /// at the beginning of each call to runOnMachineFunction().
55    ///
56    typedef std::map<const Value *, unsigned> ValueMapTy;
57    ValueMapTy NumberForBB;
58
59    /// Cache of mangled name for current function. This is
60    /// recalculated at the beginning of each call to
61    /// runOnMachineFunction().
62    ///
63    std::string CurrentFnName;
64
65    virtual const char *getPassName() const {
66      return "SparcV8 Assembly Printer";
67    }
68
69    void emitConstantValueOnly(const Constant *CV);
70    void emitGlobalConstant(const Constant *CV);
71    void printConstantPool(MachineConstantPool *MCP);
72    void printOperand(const MachineInstr *MI, int opNum);
73    void printBaseOffsetPair (const MachineInstr *MI, int i, bool brackets=true);
74    void printMachineInstruction(const MachineInstr *MI);
75    bool runOnMachineFunction(MachineFunction &F);
76    bool doInitialization(Module &M);
77    bool doFinalization(Module &M);
78  };
79} // end of anonymous namespace
80
81/// createSparcV8CodePrinterPass - Returns a pass that prints the SparcV8
82/// assembly code for a MachineFunction to the given output stream,
83/// using the given target machine description.  This should work
84/// regardless of whether the function is in SSA form.
85///
86FunctionPass *llvm::createSparcV8CodePrinterPass (std::ostream &o,
87                                                  TargetMachine &tm) {
88  return new V8Printer(o, tm);
89}
90
91/// toOctal - Convert the low order bits of X into an octal digit.
92///
93static inline char toOctal(int X) {
94  return (X&7)+'0';
95}
96
97/// getAsCString - Return the specified array as a C compatible
98/// string, only if the predicate isStringCompatible is true.
99///
100static void printAsCString(std::ostream &O, const ConstantArray *CVA) {
101  assert(CVA->isString() && "Array is not string compatible!");
102
103  O << "\"";
104  for (unsigned i = 0; i != CVA->getNumOperands(); ++i) {
105    unsigned char C = cast<ConstantInt>(CVA->getOperand(i))->getRawValue();
106
107    if (C == '"') {
108      O << "\\\"";
109    } else if (C == '\\') {
110      O << "\\\\";
111    } else if (isprint(C)) {
112      O << C;
113    } else {
114      switch(C) {
115      case '\b': O << "\\b"; break;
116      case '\f': O << "\\f"; break;
117      case '\n': O << "\\n"; break;
118      case '\r': O << "\\r"; break;
119      case '\t': O << "\\t"; break;
120      default:
121        O << '\\';
122        O << toOctal(C >> 6);
123        O << toOctal(C >> 3);
124        O << toOctal(C >> 0);
125        break;
126      }
127    }
128  }
129  O << "\"";
130}
131
132// Print out the specified constant, without a storage class.  Only the
133// constants valid in constant expressions can occur here.
134void V8Printer::emitConstantValueOnly(const Constant *CV) {
135  if (CV->isNullValue() || isa<UndefValue> (CV))
136    O << "0";
137  else if (const ConstantBool *CB = dyn_cast<ConstantBool>(CV)) {
138    assert(CB == ConstantBool::True);
139    O << "1";
140  } else if (const ConstantSInt *CI = dyn_cast<ConstantSInt>(CV))
141    if (((CI->getValue() << 32) >> 32) == CI->getValue())
142      O << CI->getValue();
143    else
144      O << (unsigned long long)CI->getValue();
145  else if (const ConstantUInt *CI = dyn_cast<ConstantUInt>(CV))
146    O << CI->getValue();
147  else if (const GlobalValue *GV = dyn_cast<GlobalValue>(CV))
148    // This is a constant address for a global variable or function.  Use the
149    // name of the variable or function as the address value.
150    O << Mang->getValueName(GV);
151  else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
152    const TargetData &TD = TM.getTargetData();
153    switch(CE->getOpcode()) {
154    case Instruction::GetElementPtr: {
155      // generate a symbolic expression for the byte address
156      const Constant *ptrVal = CE->getOperand(0);
157      std::vector<Value*> idxVec(CE->op_begin()+1, CE->op_end());
158      if (unsigned Offset = TD.getIndexedOffset(ptrVal->getType(), idxVec)) {
159        O << "(";
160        emitConstantValueOnly(ptrVal);
161        O << ") + " << Offset;
162      } else {
163        emitConstantValueOnly(ptrVal);
164      }
165      break;
166    }
167    case Instruction::Cast: {
168      // Support only non-converting or widening casts for now, that is, ones
169      // that do not involve a change in value.  This assertion is really gross,
170      // and may not even be a complete check.
171      Constant *Op = CE->getOperand(0);
172      const Type *OpTy = Op->getType(), *Ty = CE->getType();
173
174      // Pointers on ILP32 machines can be losslessly converted back and
175      // forth into 32-bit or wider integers, regardless of signedness.
176      assert(((isa<PointerType>(OpTy)
177               && (Ty == Type::LongTy || Ty == Type::ULongTy
178                   || Ty == Type::IntTy || Ty == Type::UIntTy))
179              || (isa<PointerType>(Ty)
180                  && (OpTy == Type::LongTy || OpTy == Type::ULongTy
181                      || OpTy == Type::IntTy || OpTy == Type::UIntTy))
182              || (((TD.getTypeSize(Ty) >= TD.getTypeSize(OpTy))
183                   && OpTy->isLosslesslyConvertibleTo(Ty))))
184             && "FIXME: Don't yet support this kind of constant cast expr");
185      O << "(";
186      emitConstantValueOnly(Op);
187      O << ")";
188      break;
189    }
190    case Instruction::Add:
191      O << "(";
192      emitConstantValueOnly(CE->getOperand(0));
193      O << ") + (";
194      emitConstantValueOnly(CE->getOperand(1));
195      O << ")";
196      break;
197    default:
198      assert(0 && "Unsupported operator!");
199    }
200  } else {
201    assert(0 && "Unknown constant value!");
202  }
203}
204
205// Print a constant value or values, with the appropriate storage class as a
206// prefix.
207void V8Printer::emitGlobalConstant(const Constant *CV) {
208  const TargetData &TD = TM.getTargetData();
209
210  if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) {
211    if (CVA->isString()) {
212      O << "\t.ascii\t";
213      printAsCString(O, CVA);
214      O << "\n";
215    } else { // Not a string.  Print the values in successive locations
216      for (unsigned i = 0, e = CVA->getNumOperands(); i != e; i++)
217        emitGlobalConstant(CVA->getOperand(i));
218    }
219    return;
220  } else if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) {
221    // Print the fields in successive locations. Pad to align if needed!
222    const StructLayout *cvsLayout = TD.getStructLayout(CVS->getType());
223    unsigned sizeSoFar = 0;
224    for (unsigned i = 0, e = CVS->getNumOperands(); i != e; i++) {
225      const Constant* field = CVS->getOperand(i);
226
227      // Check if padding is needed and insert one or more 0s.
228      unsigned fieldSize = TD.getTypeSize(field->getType());
229      unsigned padSize = ((i == e-1? cvsLayout->StructSize
230                           : cvsLayout->MemberOffsets[i+1])
231                          - cvsLayout->MemberOffsets[i]) - fieldSize;
232      sizeSoFar += fieldSize + padSize;
233
234      // Now print the actual field value
235      emitGlobalConstant(field);
236
237      // Insert the field padding unless it's zero bytes...
238      if (padSize)
239        O << "\t.skip\t " << padSize << "\n";
240    }
241    assert(sizeSoFar == cvsLayout->StructSize &&
242           "Layout of constant struct may be incorrect!");
243    return;
244  } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) {
245    // FP Constants are printed as integer constants to avoid losing
246    // precision...
247    double Val = CFP->getValue();
248    switch (CFP->getType()->getTypeID()) {
249    default: assert(0 && "Unknown floating point type!");
250    case Type::FloatTyID: {
251      O << ".long\t" << FloatToBits(Val) << "\t! float " << Val << "\n";
252      return;
253    }
254    case Type::DoubleTyID: {
255      O << ".word\t0x" << std::hex << (DoubleToBits(Val) >> 32) << std::dec << "\t! double " << Val << "\n";
256      O << ".word\t0x" << std::hex << (DoubleToBits(Val) & 0xffffffffUL) << std::dec << "\t! double " << Val << "\n";
257      return;
258    }
259    }
260  } else if (isa<UndefValue> (CV)) {
261    unsigned size = TD.getTypeSize (CV->getType ());
262    O << "\t.skip\t " << size << "\n";
263    return;
264  } else if (isa<ConstantAggregateZero> (CV)) {
265    unsigned size = TD.getTypeSize (CV->getType ());
266    for (unsigned i = 0; i < size; ++i)
267      O << "\t.byte 0\n";
268    return;
269  }
270
271  const Type *type = CV->getType();
272  O << "\t";
273  switch (type->getTypeID()) {
274  case Type::BoolTyID: case Type::UByteTyID: case Type::SByteTyID:
275    O << ".byte";
276    break;
277  case Type::UShortTyID: case Type::ShortTyID:
278    O << ".half";
279    break;
280  case Type::FloatTyID: case Type::PointerTyID:
281  case Type::UIntTyID: case Type::IntTyID:
282    O << ".word";
283    break;
284  case Type::DoubleTyID:
285  case Type::ULongTyID: case Type::LongTyID:
286    O << ".xword";
287    break;
288  default:
289    assert (0 && "Can't handle printing this type of thing");
290    break;
291  }
292  O << "\t";
293  emitConstantValueOnly(CV);
294  O << "\n";
295}
296
297/// printConstantPool - Print to the current output stream assembly
298/// representations of the constants in the constant pool MCP. This is
299/// used to print out constants which have been "spilled to memory" by
300/// the code generator.
301///
302void V8Printer::printConstantPool(MachineConstantPool *MCP) {
303  const std::vector<Constant*> &CP = MCP->getConstants();
304  const TargetData &TD = TM.getTargetData();
305
306  if (CP.empty()) return;
307
308  for (unsigned i = 0, e = CP.size(); i != e; ++i) {
309    O << "\t.section \".rodata\"\n";
310    O << "\t.align " << (unsigned)TD.getTypeAlignment(CP[i]->getType())
311      << "\n";
312    O << ".CPI" << CurrentFnName << "_" << i << ":\t\t\t\t\t!"
313      << *CP[i] << "\n";
314    emitGlobalConstant(CP[i]);
315  }
316}
317
318/// runOnMachineFunction - This uses the printMachineInstruction()
319/// method to print assembly for each instruction.
320///
321bool V8Printer::runOnMachineFunction(MachineFunction &MF) {
322  // BBNumber is used here so that a given Printer will never give two
323  // BBs the same name. (If you have a better way, please let me know!)
324  static unsigned BBNumber = 0;
325
326  O << "\n\n";
327  // What's my mangled name?
328  CurrentFnName = Mang->getValueName(MF.getFunction());
329
330  // Print out constants referenced by the function
331  printConstantPool(MF.getConstantPool());
332
333  // Print out labels for the function.
334  O << "\t.text\n";
335  O << "\t.align 16\n";
336  O << "\t.globl\t" << CurrentFnName << "\n";
337  O << "\t.type\t" << CurrentFnName << ", #function\n";
338  O << CurrentFnName << ":\n";
339
340  // Number each basic block so that we can consistently refer to them
341  // in PC-relative references.
342  NumberForBB.clear();
343  for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
344       I != E; ++I) {
345    NumberForBB[I->getBasicBlock()] = BBNumber++;
346  }
347
348  // Print out code for the function.
349  for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
350       I != E; ++I) {
351    // Print a label for the basic block.
352    O << ".LBB" << Mang->getValueName(MF.getFunction ())
353      << "_" << I->getNumber () << ":\t! "
354      << I->getBasicBlock ()->getName () << "\n";
355    for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
356         II != E; ++II) {
357      // Print the assembly for the instruction.
358      O << "\t";
359      printMachineInstruction(II);
360    }
361  }
362
363  // We didn't modify anything.
364  return false;
365}
366
367void V8Printer::printOperand(const MachineInstr *MI, int opNum) {
368  const MachineOperand &MO = MI->getOperand (opNum);
369  const MRegisterInfo &RI = *TM.getRegisterInfo();
370  bool CloseParen = false;
371  if (MI->getOpcode() == V8::SETHIi && !MO.isRegister() && !MO.isImmediate()) {
372    O << "%hi(";
373    CloseParen = true;
374  } else if (MI->getOpcode() ==V8::ORri &&!MO.isRegister() &&!MO.isImmediate())
375  {
376    O << "%lo(";
377    CloseParen = true;
378  }
379  switch (MO.getType()) {
380  case MachineOperand::MO_VirtualRegister:
381    if (Value *V = MO.getVRegValueOrNull()) {
382      O << "<" << V->getName() << ">";
383      break;
384    }
385    // FALLTHROUGH
386  case MachineOperand::MO_MachineRegister:
387    if (MRegisterInfo::isPhysicalRegister(MO.getReg()))
388      O << "%" << LowercaseString (RI.get(MO.getReg()).Name);
389    else
390      O << "%reg" << MO.getReg();
391    break;
392
393  case MachineOperand::MO_SignExtendedImmed:
394  case MachineOperand::MO_UnextendedImmed:
395    O << (int)MO.getImmedValue();
396    break;
397  case MachineOperand::MO_MachineBasicBlock: {
398    MachineBasicBlock *MBBOp = MO.getMachineBasicBlock();
399    O << ".LBB" << Mang->getValueName(MBBOp->getParent()->getFunction())
400      << "_" << MBBOp->getNumber () << "\t! "
401      << MBBOp->getBasicBlock ()->getName ();
402    return;
403  }
404  case MachineOperand::MO_PCRelativeDisp:
405    std::cerr << "Shouldn't use addPCDisp() when building SparcV8 MachineInstrs";
406    abort ();
407    return;
408  case MachineOperand::MO_GlobalAddress:
409    O << Mang->getValueName(MO.getGlobal());
410    break;
411  case MachineOperand::MO_ExternalSymbol:
412    O << MO.getSymbolName();
413    break;
414  case MachineOperand::MO_ConstantPoolIndex:
415    O << ".CPI" << CurrentFnName << "_" << MO.getConstantPoolIndex();
416    break;
417  default:
418    O << "<unknown operand type>"; abort (); break;
419  }
420  if (CloseParen) O << ")";
421}
422
423static bool isLoadInstruction (const MachineInstr *MI) {
424  switch (MI->getOpcode ()) {
425  case V8::LDSB:
426  case V8::LDSH:
427  case V8::LDUB:
428  case V8::LDUH:
429  case V8::LD:
430  case V8::LDD:
431  case V8::LDFrr:
432  case V8::LDFri:
433  case V8::LDDFrr:
434  case V8::LDDFri:
435    return true;
436  default:
437    return false;
438  }
439}
440
441static bool isStoreInstruction (const MachineInstr *MI) {
442  switch (MI->getOpcode ()) {
443  case V8::STB:
444  case V8::STH:
445  case V8::ST:
446  case V8::STD:
447  case V8::STFrr:
448  case V8::STFri:
449  case V8::STDFrr:
450  case V8::STDFri:
451    return true;
452  default:
453    return false;
454  }
455}
456
457static bool isPseudoInstruction (const MachineInstr *MI) {
458  switch (MI->getOpcode ()) {
459  case V8::PHI:
460  case V8::ADJCALLSTACKUP:
461  case V8::ADJCALLSTACKDOWN:
462  case V8::IMPLICIT_USE:
463  case V8::IMPLICIT_DEF:
464    return true;
465  default:
466    return false;
467  }
468}
469
470/// printBaseOffsetPair - Print two consecutive operands of MI, starting at #i,
471/// which form a base + offset pair (which may have brackets around it, if
472/// brackets is true, or may be in the form base - constant, if offset is a
473/// negative constant).
474///
475void V8Printer::printBaseOffsetPair (const MachineInstr *MI, int i,
476                                     bool brackets) {
477  if (brackets) O << "[";
478  printOperand (MI, i);
479  if (MI->getOperand (i + 1).isImmediate()) {
480    int Val = (int) MI->getOperand (i + 1).getImmedValue ();
481    if (Val != 0) {
482      O << ((Val >= 0) ? " + " : " - ");
483      O << ((Val >= 0) ? Val : -Val);
484    }
485  } else {
486    O << " + ";
487    printOperand (MI, i + 1);
488  }
489  if (brackets) O << "]";
490}
491
492/// printMachineInstruction -- Print out a single SparcV8 LLVM instruction
493/// MI in GAS syntax to the current output stream.
494///
495void V8Printer::printMachineInstruction(const MachineInstr *MI) {
496  unsigned Opcode = MI->getOpcode();
497  const TargetInstrInfo &TII = *TM.getInstrInfo();
498  const TargetInstrDescriptor &Desc = TII.get(Opcode);
499
500  // If it's a pseudo-instruction, comment it out.
501  if (isPseudoInstruction (MI))
502    O << "! ";
503
504  O << Desc.Name << " ";
505
506  // Printing memory instructions is a special case.
507  // for loads:  %dest = op %base, offset --> op [%base + offset], %dest
508  // for stores: op %base, offset, %src   --> op %src, [%base + offset]
509  if (isLoadInstruction (MI)) {
510    printBaseOffsetPair (MI, 1);
511    O << ", ";
512    printOperand (MI, 0);
513    O << "\n";
514    return;
515  } else if (isStoreInstruction (MI)) {
516    printOperand (MI, 2);
517    O << ", ";
518    printBaseOffsetPair (MI, 0);
519    O << "\n";
520    return;
521  } else if (Opcode == V8::JMPLrr) {
522    printBaseOffsetPair (MI, 1, false);
523    O << ", ";
524    printOperand (MI, 0);
525    O << "\n";
526    return;
527  }
528
529  // print non-immediate, non-register-def operands
530  // then print immediate operands
531  // then print register-def operands.
532  std::vector<int> print_order;
533  for (unsigned i = 0; i < MI->getNumOperands (); ++i)
534    if (!(MI->getOperand (i).isImmediate ()
535          || (MI->getOperand (i).isRegister ()
536              && MI->getOperand (i).isDef ())))
537      print_order.push_back (i);
538  for (unsigned i = 0; i < MI->getNumOperands (); ++i)
539    if (MI->getOperand (i).isImmediate ())
540      print_order.push_back (i);
541  for (unsigned i = 0; i < MI->getNumOperands (); ++i)
542    if (MI->getOperand (i).isRegister () && MI->getOperand (i).isDef ())
543      print_order.push_back (i);
544  for (unsigned i = 0, e = print_order.size (); i != e; ++i) {
545    printOperand (MI, print_order[i]);
546    if (i != (print_order.size () - 1))
547      O << ", ";
548  }
549  O << "\n";
550}
551
552bool V8Printer::doInitialization(Module &M) {
553  Mang = new Mangler(M);
554  return false; // success
555}
556
557// SwitchSection - Switch to the specified section of the executable if we are
558// not already in it!
559//
560static void SwitchSection(std::ostream &OS, std::string &CurSection,
561                          const char *NewSection) {
562  if (CurSection != NewSection) {
563    CurSection = NewSection;
564    if (!CurSection.empty())
565      OS << "\t.section \"" << NewSection << "\"\n";
566  }
567}
568
569bool V8Printer::doFinalization(Module &M) {
570  const TargetData &TD = TM.getTargetData();
571  std::string CurSection;
572
573  // Print out module-level global variables here.
574  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end(); I != E; ++I)
575    if (I->hasInitializer()) {   // External global require no code
576      O << "\n\n";
577      std::string name = Mang->getValueName(I);
578      Constant *C = I->getInitializer();
579      unsigned Size = TD.getTypeSize(C->getType());
580      unsigned Align = TD.getTypeAlignment(C->getType());
581
582      if (C->isNullValue() &&
583          (I->hasLinkOnceLinkage() || I->hasInternalLinkage() ||
584           I->hasWeakLinkage() /* FIXME: Verify correct */)) {
585        SwitchSection(O, CurSection, ".data");
586        if (I->hasInternalLinkage())
587          O << "\t.local " << name << "\n";
588
589        O << "\t.comm " << name << "," << TD.getTypeSize(C->getType())
590          << "," << (unsigned)TD.getTypeAlignment(C->getType());
591        O << "\t\t! ";
592        WriteAsOperand(O, I, true, true, &M);
593        O << "\n";
594      } else {
595        switch (I->getLinkage()) {
596        case GlobalValue::LinkOnceLinkage:
597        case GlobalValue::WeakLinkage:   // FIXME: Verify correct for weak.
598          // Nonnull linkonce -> weak
599          O << "\t.weak " << name << "\n";
600          SwitchSection(O, CurSection, "");
601          O << "\t.section\t\".llvm.linkonce.d." << name << "\",\"aw\",@progbits\n";
602          break;
603
604        case GlobalValue::AppendingLinkage:
605          // FIXME: appending linkage variables should go into a section of
606          // their name or something.  For now, just emit them as external.
607        case GlobalValue::ExternalLinkage:
608          // If external or appending, declare as a global symbol
609          O << "\t.globl " << name << "\n";
610          // FALL THROUGH
611        case GlobalValue::InternalLinkage:
612          if (C->isNullValue())
613            SwitchSection(O, CurSection, ".bss");
614          else
615            SwitchSection(O, CurSection, ".data");
616          break;
617        case GlobalValue::GhostLinkage:
618          std::cerr << "Should not have any unmaterialized functions!\n";
619          abort();
620        }
621
622        O << "\t.align " << Align << "\n";
623        O << "\t.type " << name << ",#object\n";
624        O << "\t.size " << name << "," << Size << "\n";
625        O << name << ":\t\t\t\t! ";
626        WriteAsOperand(O, I, true, true, &M);
627        O << " = ";
628        WriteAsOperand(O, C, false, false, &M);
629        O << "\n";
630        emitGlobalConstant(C);
631      }
632    }
633
634  delete Mang;
635  return false; // success
636}
637