SparcAsmPrinter.cpp revision 446ae11d7c1a6a2a3ce5080bab60123f4dfe63e1 
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 "Support/Statistic.h"
27#include "Support/StringExtras.h"
28#include "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);
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())
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 ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(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(CPR->getValue());
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 (CV->isNullValue()) {
210    O << "\t.zero\t " << TD.getTypeSize(CV->getType()) << "\n";
211    return;
212  } else if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) {
213    if (CVA->isString()) {
214      O << "\t.ascii\t";
215      printAsCString(O, CVA);
216      O << "\n";
217    } else { // Not a string.  Print the values in successive locations
218      const std::vector<Use> &constValues = CVA->getValues();
219      for (unsigned i=0; i < constValues.size(); i++)
220        emitGlobalConstant(cast<Constant>(constValues[i].get()));
221    }
222    return;
223  } else if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) {
224    // Print the fields in successive locations. Pad to align if needed!
225    const StructLayout *cvsLayout = TD.getStructLayout(CVS->getType());
226    const std::vector<Use>& constValues = CVS->getValues();
227    unsigned sizeSoFar = 0;
228    for (unsigned i=0, N = constValues.size(); i < N; i++) {
229      const Constant* field = cast<Constant>(constValues[i].get());
230
231      // Check if padding is needed and insert one or more 0s.
232      unsigned fieldSize = TD.getTypeSize(field->getType());
233      unsigned padSize = ((i == N-1? cvsLayout->StructSize
234                           : cvsLayout->MemberOffsets[i+1])
235                          - cvsLayout->MemberOffsets[i]) - fieldSize;
236      sizeSoFar += fieldSize + padSize;
237
238      // Now print the actual field value
239      emitGlobalConstant(field);
240
241      // Insert the field padding unless it's zero bytes...
242      if (padSize)
243        O << "\t.zero\t " << padSize << "\n";
244    }
245    assert(sizeSoFar == cvsLayout->StructSize &&
246           "Layout of constant struct may be incorrect!");
247    return;
248  } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) {
249    // FP Constants are printed as integer constants to avoid losing
250    // precision...
251    double Val = CFP->getValue();
252    switch (CFP->getType()->getPrimitiveID()) {
253    default: assert(0 && "Unknown floating point type!");
254    case Type::FloatTyID: {
255      union FU {                            // Abide by C TBAA rules
256        float FVal;
257        unsigned UVal;
258      } U;
259      U.FVal = Val;
260      O << ".long\t" << U.UVal << "\t! float " << Val << "\n";
261      return;
262    }
263    case Type::DoubleTyID: {
264      union DU {                            // Abide by C TBAA rules
265        double FVal;
266        uint64_t UVal;
267      } U;
268      U.FVal = Val;
269      O << ".quad\t" << U.UVal << "\t! double " << Val << "\n";
270      return;
271    }
272    }
273  }
274
275  const Type *type = CV->getType();
276  O << "\t";
277  switch (type->getPrimitiveID()) {
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" << NumberForBB[I->getBasicBlock()] << ":\t! "
357      << I->getBasicBlock()->getName() << "\n";
358    for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
359	 II != E; ++II) {
360      // Print the assembly for the instruction.
361      O << "\t";
362      printMachineInstruction(II);
363    }
364  }
365
366  // We didn't modify anything.
367  return false;
368}
369
370
371std::string LowercaseString (const std::string &S) {
372  std::string result (S);
373  for (unsigned i = 0; i < S.length(); ++i)
374    if (isupper (result[i]))
375      result[i] = tolower(result[i]);
376  return result;
377}
378
379void V8Printer::printOperand(const MachineInstr *MI, int opNum) {
380  const MachineOperand &MO = MI->getOperand (opNum);
381  const MRegisterInfo &RI = *TM.getRegisterInfo();
382  bool CloseParen = false;
383  if (MI->getOpcode() == V8::SETHIi && !MO.isRegister() && !MO.isImmediate()) {
384    O << "%hi(";
385    CloseParen = true;
386  } else if (MI->getOpcode() ==V8::ORri &&!MO.isRegister() &&!MO.isImmediate()) {
387    O << "%lo(";
388    CloseParen = true;
389  }
390  switch (MO.getType()) {
391  case MachineOperand::MO_VirtualRegister:
392    if (Value *V = MO.getVRegValueOrNull()) {
393      O << "<" << V->getName() << ">";
394      break;
395    }
396    // FALLTHROUGH
397  case MachineOperand::MO_MachineRegister:
398    if (MRegisterInfo::isPhysicalRegister(MO.getReg()))
399      O << "%" << LowercaseString (RI.get(MO.getReg()).Name);
400    else
401      O << "%reg" << MO.getReg();
402    break;
403
404  case MachineOperand::MO_SignExtendedImmed:
405  case MachineOperand::MO_UnextendedImmed:
406    O << (int)MO.getImmedValue();
407    break;
408  case MachineOperand::MO_PCRelativeDisp: {
409    if (isa<GlobalValue> (MO.getVRegValue ())) {
410      O << Mang->getValueName (MO.getVRegValue ());
411      break;
412    }
413    assert (isa<BasicBlock> (MO.getVRegValue ())
414      && "Trying to look up something which is not a BB in the NumberForBB map");
415    ValueMapTy::const_iterator i = NumberForBB.find(MO.getVRegValue());
416    assert (i != NumberForBB.end()
417            && "Could not find a BB in the NumberForBB map!");
418    O << ".LBB" << i->second << " ! PC rel: " << MO.getVRegValue()->getName();
419    break;
420  }
421  case MachineOperand::MO_GlobalAddress:
422    O << Mang->getValueName(MO.getGlobal());
423    break;
424  case MachineOperand::MO_ExternalSymbol:
425    O << MO.getSymbolName();
426    break;
427  default:
428    O << "<unknown operand type>"; break;
429  }
430  if (CloseParen) O << ")";
431}
432
433static bool isLoadInstruction (const MachineInstr *MI) {
434  switch (MI->getOpcode ()) {
435  case V8::LDSBmr:
436  case V8::LDSHmr:
437  case V8::LDUBmr:
438  case V8::LDUHmr:
439  case V8::LDmr:
440  case V8::LDDmr:
441    return true;
442  default:
443    return false;
444  }
445}
446
447static bool isStoreInstruction (const MachineInstr *MI) {
448  switch (MI->getOpcode ()) {
449  case V8::STBrm:
450  case V8::STHrm:
451  case V8::STrm:
452  case V8::STDrm:
453    return true;
454  default:
455    return false;
456  }
457}
458
459void V8Printer::printBaseOffsetPair (const MachineInstr *MI, int i) {
460  O << "[";
461  printOperand (MI, i);
462  assert (MI->getOperand (i + 1).isImmediate()
463    && "2nd half of base-offset pair must be immediate-value machine operand");
464  int Val = (int) MI->getOperand (i + 1).getImmedValue ();
465  if (Val != 0) {
466    O << ((Val >= 0) ? " + " : " - ");
467    O << ((Val >= 0) ? Val : -Val);
468  }
469  O << "]";
470}
471
472/// printMachineInstruction -- Print out a single SparcV8 LLVM instruction
473/// MI in GAS syntax to the current output stream.
474///
475void V8Printer::printMachineInstruction(const MachineInstr *MI) {
476  unsigned Opcode = MI->getOpcode();
477  const TargetInstrInfo &TII = *TM.getInstrInfo();
478  const TargetInstrDescriptor &Desc = TII.get(Opcode);
479  O << Desc.Name << " ";
480
481  // Printing memory instructions is a special case.
482  // for loads:  %dest = op %base, offset --> op [%base + offset], %dest
483  // for stores: op %src, %base, offset   --> op %src, [%base + offset]
484  if (isLoadInstruction (MI)) {
485    printBaseOffsetPair (MI, 1);
486    O << ", ";
487    printOperand (MI, 0);
488    O << "\n";
489    return;
490  } else if (isStoreInstruction (MI)) {
491    printOperand (MI, 0);
492    O << ", ";
493    printBaseOffsetPair (MI, 1);
494    O << "\n";
495    return;
496  }
497
498  // print non-immediate, non-register-def operands
499  // then print immediate operands
500  // then print register-def operands.
501  std::vector<int> print_order;
502  for (unsigned i = 0; i < MI->getNumOperands (); ++i)
503    if (!(MI->getOperand (i).isImmediate ()
504          || (MI->getOperand (i).isRegister ()
505              && MI->getOperand (i).isDef ())))
506      print_order.push_back (i);
507  for (unsigned i = 0; i < MI->getNumOperands (); ++i)
508    if (MI->getOperand (i).isImmediate ())
509      print_order.push_back (i);
510  for (unsigned i = 0; i < MI->getNumOperands (); ++i)
511    if (MI->getOperand (i).isRegister () && MI->getOperand (i).isDef ())
512      print_order.push_back (i);
513  for (unsigned i = 0, e = print_order.size (); i != e; ++i) {
514    printOperand (MI, print_order[i]);
515    if (i != (print_order.size () - 1))
516      O << ", ";
517  }
518  O << "\n";
519}
520
521bool V8Printer::doInitialization(Module &M) {
522  Mang = new Mangler(M);
523  return false; // success
524}
525
526// SwitchSection - Switch to the specified section of the executable if we are
527// not already in it!
528//
529static void SwitchSection(std::ostream &OS, std::string &CurSection,
530                          const char *NewSection) {
531  if (CurSection != NewSection) {
532    CurSection = NewSection;
533    if (!CurSection.empty())
534      OS << "\t" << NewSection << "\n";
535  }
536}
537
538bool V8Printer::doFinalization(Module &M) {
539  const TargetData &TD = TM.getTargetData();
540  std::string CurSection;
541
542  // Print out module-level global variables here.
543  for (Module::const_giterator I = M.gbegin(), E = M.gend(); I != E; ++I)
544    if (I->hasInitializer()) {   // External global require no code
545      O << "\n\n";
546      std::string name = Mang->getValueName(I);
547      Constant *C = I->getInitializer();
548      unsigned Size = TD.getTypeSize(C->getType());
549      unsigned Align = TD.getTypeAlignment(C->getType());
550
551      if (C->isNullValue() &&
552          (I->hasLinkOnceLinkage() || I->hasInternalLinkage() ||
553           I->hasWeakLinkage() /* FIXME: Verify correct */)) {
554        SwitchSection(O, CurSection, ".data");
555        if (I->hasInternalLinkage())
556          O << "\t.local " << name << "\n";
557
558        O << "\t.comm " << name << "," << TD.getTypeSize(C->getType())
559          << "," << (unsigned)TD.getTypeAlignment(C->getType());
560        O << "\t\t! ";
561        WriteAsOperand(O, I, true, true, &M);
562        O << "\n";
563      } else {
564        switch (I->getLinkage()) {
565        case GlobalValue::LinkOnceLinkage:
566        case GlobalValue::WeakLinkage:   // FIXME: Verify correct for weak.
567          // Nonnull linkonce -> weak
568          O << "\t.weak " << name << "\n";
569          SwitchSection(O, CurSection, "");
570          O << "\t.section\t.llvm.linkonce.d." << name << ",\"aw\",@progbits\n";
571          break;
572
573        case GlobalValue::AppendingLinkage:
574          // FIXME: appending linkage variables should go into a section of
575          // their name or something.  For now, just emit them as external.
576        case GlobalValue::ExternalLinkage:
577          // If external or appending, declare as a global symbol
578          O << "\t.globl " << name << "\n";
579          // FALL THROUGH
580        case GlobalValue::InternalLinkage:
581          if (C->isNullValue())
582            SwitchSection(O, CurSection, ".bss");
583          else
584            SwitchSection(O, CurSection, ".data");
585          break;
586        }
587
588        O << "\t.align " << Align << "\n";
589        O << "\t.type " << name << ",#object\n";
590        O << "\t.size " << name << "," << Size << "\n";
591        O << name << ":\t\t\t\t! ";
592        WriteAsOperand(O, I, true, true, &M);
593        O << " = ";
594        WriteAsOperand(O, C, false, false, &M);
595        O << "\n";
596        emitGlobalConstant(C);
597      }
598    }
599
600  delete Mang;
601  return false; // success
602}
603