lib/Target/X86/AsmPrinter/X86IntelAsmPrinter.cpp

   1 //===-- X86IntelAsmPrinter.cpp - Convert X86 LLVM code to Intel assembly --===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file contains a printer that converts from our internal representation
  11 // of machine-dependent LLVM code to Intel format assembly language.
  12 // This printer is the output mechanism used by `llc'.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #define DEBUG_TYPE "asm-printer"
  17 #include "X86IntelAsmPrinter.h"
  18 #include "X86InstrInfo.h"
  19 #include "X86TargetAsmInfo.h"
  20 #include "X86.h"
  21 #include "llvm/CallingConv.h"
  22 #include "llvm/Constants.h"
  23 #include "llvm/DerivedTypes.h"
  24 #include "llvm/Module.h"
  25 #include "llvm/ADT/Statistic.h"
  26 #include "llvm/ADT/StringExtras.h"
  27 #include "llvm/Assembly/Writer.h"
  28 #include "llvm/CodeGen/DwarfWriter.h"
  29 #include "llvm/Analysis/DebugInfo.h"
  30 #include "llvm/Support/Mangler.h"
  31 #include "llvm/Target/TargetAsmInfo.h"
  32 #include "llvm/Target/TargetOptions.h"
  33 using namespace llvm;
  34
  35 STATISTIC(EmittedInsts, "Number of machine instrs printed");
  36
  37 static X86MachineFunctionInfo calculateFunctionInfo(const Function *F,
  38                                                     const TargetData *TD) {
  39   X86MachineFunctionInfo Info;
  40   uint64_t Size = 0;
  41
  42   switch (F->getCallingConv()) {
  43   case CallingConv::X86_StdCall:
  44     Info.setDecorationStyle(StdCall);
  45     break;
  46   case CallingConv::X86_FastCall:
  47     Info.setDecorationStyle(FastCall);
  48     break;
  49   default:
  50     return Info;
  51   }
  52
  53   unsigned argNum = 1;
  54   for (Function::const_arg_iterator AI = F->arg_begin(), AE = F->arg_end();
  55        AI != AE; ++AI, ++argNum) {
  56     const Type* Ty = AI->getType();
  57
  58     // 'Dereference' type in case of byval parameter attribute
  59     if (F->paramHasAttr(argNum, Attribute::ByVal))
  60       Ty = cast<PointerType>(Ty)->getElementType();
  61
  62     // Size should be aligned to DWORD boundary
  63     Size += ((TD->getTypePaddedSize(Ty) + 3)/4)*4;
  64   }
  65
  66   // We're not supporting tooooo huge arguments :)
  67   Info.setBytesToPopOnReturn((unsigned int)Size);
  68   return Info;
  69 }
  70
  71
  72 /// decorateName - Query FunctionInfoMap and use this information for various
  73 /// name decoration.
  74 void X86IntelAsmPrinter::decorateName(std::string &Name,
  75                                       const GlobalValue *GV) {
  76   const Function *F = dyn_cast<Function>(GV);
  77   if (!F) return;
  78
  79   // We don't want to decorate non-stdcall or non-fastcall functions right now
  80   unsigned CC = F->getCallingConv();
  81   if (CC != CallingConv::X86_StdCall && CC != CallingConv::X86_FastCall)
  82     return;
  83
  84   FMFInfoMap::const_iterator info_item = FunctionInfoMap.find(F);
  85
  86   const X86MachineFunctionInfo *Info;
  87   if (info_item == FunctionInfoMap.end()) {
  88     // Calculate apropriate function info and populate map
  89     FunctionInfoMap[F] = calculateFunctionInfo(F, TM.getTargetData());
  90     Info = &FunctionInfoMap[F];
  91   } else {
  92     Info = &info_item->second;
  93   }
  94
  95   const FunctionType *FT = F->getFunctionType();
  96   switch (Info->getDecorationStyle()) {
  97   case None:
  98     break;
  99   case StdCall:
 100     // "Pure" variadic functions do not receive @0 suffix.
 101     if (!FT->isVarArg() || (FT->getNumParams() == 0) ||
 102         (FT->getNumParams() == 1 && F->hasStructRetAttr()))
 103       Name += '@' + utostr_32(Info->getBytesToPopOnReturn());
 104     break;
 105   case FastCall:
 106     // "Pure" variadic functions do not receive @0 suffix.
 107     if (!FT->isVarArg() || (FT->getNumParams() == 0) ||
 108         (FT->getNumParams() == 1 && F->hasStructRetAttr()))
 109       Name += '@' + utostr_32(Info->getBytesToPopOnReturn());
 110
 111     if (Name[0] == '_')
 112       Name[0] = '@';
 113     else
 114       Name = '@' + Name;
 115
 116     break;
 117   default:
 118     assert(0 && "Unsupported DecorationStyle");
 119   }
 120 }
 121
 122 /// runOnMachineFunction - This uses the printMachineInstruction()
 123 /// method to print assembly for each instruction.
 124 ///
 125 bool X86IntelAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
 126   this->MF = &MF;
 127   SetupMachineFunction(MF);
 128   O << "\n\n";
 129
 130   // Print out constants referenced by the function
 131   EmitConstantPool(MF.getConstantPool());
 132
 133   // Print out labels for the function.
 134   const Function *F = MF.getFunction();
 135   unsigned CC = F->getCallingConv();
 136
 137   // Populate function information map.  Actually, We don't want to populate
 138   // non-stdcall or non-fastcall functions' information right now.
 139   if (CC == CallingConv::X86_StdCall || CC == CallingConv::X86_FastCall)
 140     FunctionInfoMap[F] = *MF.getInfo<X86MachineFunctionInfo>();
 141
 142   decorateName(CurrentFnName, F);
 143
 144   SwitchToTextSection("_text", F);
 145
 146   unsigned FnAlign = 4;
 147   if (F->hasFnAttr(Attribute::OptimizeForSize))
 148     FnAlign = 1;
 149   switch (F->getLinkage()) {
 150   default: assert(0 && "Unsupported linkage type!");
 151   case Function::PrivateLinkage:
 152   case Function::InternalLinkage:
 153     EmitAlignment(FnAlign);
 154     break;
 155   case Function::DLLExportLinkage:
 156     DLLExportedFns.insert(CurrentFnName);
 157     //FALLS THROUGH
 158   case Function::ExternalLinkage:
 159     O << "\tpublic " << CurrentFnName << "\n";
 160     EmitAlignment(FnAlign);
 161     break;
 162   }
 163
 164   O << CurrentFnName << "\tproc near\n";
 165
 166   // Print out code for the function.
 167   for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
 168        I != E; ++I) {
 169     // Print a label for the basic block if there are any predecessors.
 170     if (!I->pred_empty()) {
 171       printBasicBlockLabel(I, true, true);
 172       O << '\n';
 173     }
 174     for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
 175          II != E; ++II) {
 176       // Print the assembly for the instruction.
 177       printMachineInstruction(II);
 178     }
 179   }
 180
 181   // Print out jump tables referenced by the function.
 182   EmitJumpTableInfo(MF.getJumpTableInfo(), MF);
 183
 184   O << CurrentFnName << "\tendp\n";
 185
 186   O.flush();
 187
 188   // We didn't modify anything.
 189   return false;
 190 }
 191
 192 void X86IntelAsmPrinter::printSSECC(const MachineInstr *MI, unsigned Op) {
 193   unsigned char value = MI->getOperand(Op).getImm();
 194   assert(value <= 7 && "Invalid ssecc argument!");
 195   switch (value) {
 196   case 0: O << "eq"; break;
 197   case 1: O << "lt"; break;
 198   case 2: O << "le"; break;
 199   case 3: O << "unord"; break;
 200   case 4: O << "neq"; break;
 201   case 5: O << "nlt"; break;
 202   case 6: O << "nle"; break;
 203   case 7: O << "ord"; break;
 204   }
 205 }
 206
 207 void X86IntelAsmPrinter::printOp(const MachineOperand &MO,
 208                                  const char *Modifier) {
 209   switch (MO.getType()) {
 210   case MachineOperand::MO_Register: {
 211     if (TargetRegisterInfo::isPhysicalRegister(MO.getReg())) {
 212       unsigned Reg = MO.getReg();
 213       if (Modifier && strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
 214         MVT VT = (strcmp(Modifier,"subreg64") == 0) ?
 215           MVT::i64 : ((strcmp(Modifier, "subreg32") == 0) ? MVT::i32 :
 216                       ((strcmp(Modifier,"subreg16") == 0) ? MVT::i16 :MVT::i8));
 217         Reg = getX86SubSuperRegister(Reg, VT);
 218       }
 219       O << TRI->getName(Reg);
 220     } else
 221       O << "reg" << MO.getReg();
 222     return;
 223   }
 224   case MachineOperand::MO_Immediate:
 225     O << MO.getImm();
 226     return;
 227   case MachineOperand::MO_MachineBasicBlock:
 228     printBasicBlockLabel(MO.getMBB());
 229     return;
 230   case MachineOperand::MO_JumpTableIndex: {
 231     bool isMemOp  = Modifier && !strcmp(Modifier, "mem");
 232     if (!isMemOp) O << "OFFSET ";
 233     O << TAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
 234       << "_" << MO.getIndex();
 235     return;
 236   }
 237   case MachineOperand::MO_ConstantPoolIndex: {
 238     bool isMemOp  = Modifier && !strcmp(Modifier, "mem");
 239     if (!isMemOp) O << "OFFSET ";
 240     O << "[" << TAI->getPrivateGlobalPrefix() << "CPI"
 241       << getFunctionNumber() << "_" << MO.getIndex();
 242     printOffset(MO.getOffset());
 243     O << "]";
 244     return;
 245   }
 246   case MachineOperand::MO_GlobalAddress: {
 247     bool isCallOp = Modifier && !strcmp(Modifier, "call");
 248     bool isMemOp  = Modifier && !strcmp(Modifier, "mem");
 249     GlobalValue *GV = MO.getGlobal();
 250     std::string Name = Mang->getValueName(GV);
 251
 252     decorateName(Name, GV);
 253
 254     if (!isMemOp && !isCallOp) O << "OFFSET ";
 255     if (GV->hasDLLImportLinkage()) {
 256       // FIXME: This should be fixed with full support of stdcall & fastcall
 257       // CC's
 258       O << "__imp_";
 259     }
 260     O << Name;
 261     printOffset(MO.getOffset());
 262     return;
 263   }
 264   case MachineOperand::MO_ExternalSymbol: {
 265     bool isCallOp = Modifier && !strcmp(Modifier, "call");
 266     if (!isCallOp) O << "OFFSET ";
 267     O << TAI->getGlobalPrefix() << MO.getSymbolName();
 268     return;
 269   }
 270   default:
 271     O << "<unknown operand type>"; return;
 272   }
 273 }
 274
 275 void X86IntelAsmPrinter::printLeaMemReference(const MachineInstr *MI,
 276                                               unsigned Op,
 277                                               const char *Modifier) {
 278   const MachineOperand &BaseReg  = MI->getOperand(Op);
 279   int ScaleVal                   = MI->getOperand(Op+1).getImm();
 280   const MachineOperand &IndexReg = MI->getOperand(Op+2);
 281   const MachineOperand &DispSpec = MI->getOperand(Op+3);
 282
 283   O << "[";
 284   bool NeedPlus = false;
 285   if (BaseReg.getReg()) {
 286     printOp(BaseReg, Modifier);
 287     NeedPlus = true;
 288   }
 289
 290   if (IndexReg.getReg()) {
 291     if (NeedPlus) O << " + ";
 292     if (ScaleVal != 1)
 293       O << ScaleVal << "*";
 294     printOp(IndexReg, Modifier);
 295     NeedPlus = true;
 296   }
 297
 298   if (DispSpec.isGlobal() || DispSpec.isCPI() ||
 299       DispSpec.isJTI()) {
 300     if (NeedPlus)
 301       O << " + ";
 302     printOp(DispSpec, "mem");
 303   } else {
 304     int DispVal = DispSpec.getImm();
 305     if (DispVal || (!BaseReg.getReg() && !IndexReg.getReg())) {
 306       if (NeedPlus) {
 307         if (DispVal > 0)
 308           O << " + ";
 309         else {
 310           O << " - ";
 311           DispVal = -DispVal;
 312         }
 313       }
 314       O << DispVal;
 315     }
 316   }
 317   O << "]";
 318 }
 319
 320 void X86IntelAsmPrinter::printMemReference(const MachineInstr *MI, unsigned Op,
 321                                            const char *Modifier) {
 322   assert(isMem(MI, Op) && "Invalid memory reference!");
 323   MachineOperand Segment = MI->getOperand(Op+4);
 324   if (Segment.getReg()) {
 325       printOperand(MI, Op+4, Modifier);
 326       O << ':';
 327     }
 328   printLeaMemReference(MI, Op, Modifier);
 329 }
 330
 331 void X86IntelAsmPrinter::printPICJumpTableSetLabel(unsigned uid,
 332                                            const MachineBasicBlock *MBB) const {
 333   if (!TAI->getSetDirective())
 334     return;
 335
 336   O << TAI->getSetDirective() << ' ' << TAI->getPrivateGlobalPrefix()
 337     << getFunctionNumber() << '_' << uid << "_set_" << MBB->getNumber() << ',';
 338   printBasicBlockLabel(MBB, false, false, false);
 339   O << '-' << "\"L" << getFunctionNumber() << "$pb\"'\n";
 340 }
 341
 342 void X86IntelAsmPrinter::printPICLabel(const MachineInstr *MI, unsigned Op) {
 343   O << "\"L" << getFunctionNumber() << "$pb\"\n";
 344   O << "\"L" << getFunctionNumber() << "$pb\":";
 345 }
 346
 347 bool X86IntelAsmPrinter::printAsmMRegister(const MachineOperand &MO,
 348                                            const char Mode) {
 349   unsigned Reg = MO.getReg();
 350   switch (Mode) {
 351   default: return true;  // Unknown mode.
 352   case 'b': // Print QImode register
 353     Reg = getX86SubSuperRegister(Reg, MVT::i8);
 354     break;
 355   case 'h': // Print QImode high register
 356     Reg = getX86SubSuperRegister(Reg, MVT::i8, true);
 357     break;
 358   case 'w': // Print HImode register
 359     Reg = getX86SubSuperRegister(Reg, MVT::i16);
 360     break;
 361   case 'k': // Print SImode register
 362     Reg = getX86SubSuperRegister(Reg, MVT::i32);
 363     break;
 364   }
 365
 366   O << '%' << TRI->getName(Reg);
 367   return false;
 368 }
 369
 370 /// PrintAsmOperand - Print out an operand for an inline asm expression.
 371 ///
 372 bool X86IntelAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
 373                                          unsigned AsmVariant,
 374                                          const char *ExtraCode) {
 375   // Does this asm operand have a single letter operand modifier?
 376   if (ExtraCode && ExtraCode[0]) {
 377     if (ExtraCode[1] != 0) return true; // Unknown modifier.
 378
 379     switch (ExtraCode[0]) {
 380     default: return true;  // Unknown modifier.
 381     case 'b': // Print QImode register
 382     case 'h': // Print QImode high register
 383     case 'w': // Print HImode register
 384     case 'k': // Print SImode register
 385       return printAsmMRegister(MI->getOperand(OpNo), ExtraCode[0]);
 386     }
 387   }
 388
 389   printOperand(MI, OpNo);
 390   return false;
 391 }
 392
 393 bool X86IntelAsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
 394                                                unsigned OpNo,
 395                                                unsigned AsmVariant,
 396                                                const char *ExtraCode) {
 397   if (ExtraCode && ExtraCode[0])
 398     return true; // Unknown modifier.
 399   printMemReference(MI, OpNo);
 400   return false;
 401 }
 402
 403 /// printMachineInstruction -- Print out a single X86 LLVM instruction
 404 /// MI in Intel syntax to the current output stream.
 405 ///
 406 void X86IntelAsmPrinter::printMachineInstruction(const MachineInstr *MI) {
 407   ++EmittedInsts;
 408
 409   // Call the autogenerated instruction printer routines.
 410   printInstruction(MI);
 411 }
 412
 413 bool X86IntelAsmPrinter::doInitialization(Module &M) {
 414   bool Result = AsmPrinter::doInitialization(M);
 415
 416   Mang->markCharUnacceptable('.');
 417
 418   O << "\t.686\n\t.model flat\n\n";
 419
 420   // Emit declarations for external functions.
 421   for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
 422     if (I->isDeclaration()) {
 423       std::string Name = Mang->getValueName(I);
 424       decorateName(Name, I);
 425
 426       O << "\textern " ;
 427       if (I->hasDLLImportLinkage()) {
 428         O << "__imp_";
 429       }
 430       O << Name << ":near\n";
 431     }
 432
 433   // Emit declarations for external globals.  Note that VC++ always declares
 434   // external globals to have type byte, and if that's good enough for VC++...
 435   for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
 436        I != E; ++I) {
 437     if (I->isDeclaration()) {
 438       std::string Name = Mang->getValueName(I);
 439
 440       O << "\textern " ;
 441       if (I->hasDLLImportLinkage()) {
 442         O << "__imp_";
 443       }
 444       O << Name << ":byte\n";
 445     }
 446   }
 447
 448   return Result;
 449 }
 450
 451 bool X86IntelAsmPrinter::doFinalization(Module &M) {
 452   const TargetData *TD = TM.getTargetData();
 453
 454   // Print out module-level global variables here.
 455   for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
 456        I != E; ++I) {
 457     if (I->isDeclaration()) continue;   // External global require no code
 458
 459     // Check to see if this is a special global used by LLVM, if so, emit it.
 460     if (EmitSpecialLLVMGlobal(I))
 461       continue;
 462
 463     std::string name = Mang->getValueName(I);
 464     Constant *C = I->getInitializer();
 465     unsigned Align = TD->getPreferredAlignmentLog(I);
 466     bool bCustomSegment = false;
 467
 468     switch (I->getLinkage()) {
 469     case GlobalValue::CommonLinkage:
 470     case GlobalValue::LinkOnceAnyLinkage:
 471     case GlobalValue::LinkOnceODRLinkage:
 472     case GlobalValue::WeakAnyLinkage:
 473     case GlobalValue::WeakODRLinkage:
 474       SwitchToDataSection("");
 475       O << name << "?\tsegment common 'COMMON'\n";
 476       bCustomSegment = true;
 477       // FIXME: the default alignment is 16 bytes, but 1, 2, 4, and 256
 478       // are also available.
 479       break;
 480     case GlobalValue::AppendingLinkage:
 481       SwitchToDataSection("");
 482       O << name << "?\tsegment public 'DATA'\n";
 483       bCustomSegment = true;
 484       // FIXME: the default alignment is 16 bytes, but 1, 2, 4, and 256
 485       // are also available.
 486       break;
 487     case GlobalValue::DLLExportLinkage:
 488       DLLExportedGVs.insert(name);
 489       // FALL THROUGH
 490     case GlobalValue::ExternalLinkage:
 491       O << "\tpublic " << name << "\n";
 492       // FALL THROUGH
 493     case GlobalValue::InternalLinkage:
 494       SwitchToSection(TAI->getDataSection());
 495       break;
 496     default:
 497       assert(0 && "Unknown linkage type!");
 498     }
 499
 500     if (!bCustomSegment)
 501       EmitAlignment(Align, I);
 502
 503     O << name << ":";
 504     if (VerboseAsm)
 505       O << "\t\t\t\t" << TAI->getCommentString()
 506         << " " << I->getName();
 507     O << '\n';
 508
 509     EmitGlobalConstant(C);
 510
 511     if (bCustomSegment)
 512       O << name << "?\tends\n";
 513   }
 514
 515     // Output linker support code for dllexported globals
 516   if (!DLLExportedGVs.empty() || !DLLExportedFns.empty()) {
 517     SwitchToDataSection("");
 518     O << "; WARNING: The following code is valid only with MASM v8.x"
 519       << "and (possible) higher\n"
 520       << "; This version of MASM is usually shipped with Microsoft "
 521       << "Visual Studio 2005\n"
 522       << "; or (possible) further versions. Unfortunately, there is no "
 523       << "way to support\n"
 524       << "; dllexported symbols in the earlier versions of MASM in fully "
 525       << "automatic way\n\n";
 526     O << "_drectve\t segment info alias('.drectve')\n";
 527   }
 528
 529   for (StringSet<>::iterator i = DLLExportedGVs.begin(),
 530          e = DLLExportedGVs.end();
 531          i != e; ++i)
 532     O << "\t db ' /EXPORT:" << i->getKeyData() << ",data'\n";
 533
 534   for (StringSet<>::iterator i = DLLExportedFns.begin(),
 535          e = DLLExportedFns.end();
 536          i != e; ++i)
 537     O << "\t db ' /EXPORT:" << i->getKeyData() << "'\n";
 538
 539   if (!DLLExportedGVs.empty() || !DLLExportedFns.empty())
 540     O << "_drectve\t ends\n";
 541
 542   // Bypass X86SharedAsmPrinter::doFinalization().
 543   bool Result = AsmPrinter::doFinalization(M);
 544   SwitchToDataSection("");
 545   O << "\tend\n";
 546   return Result;
 547 }
 548
 549 void X86IntelAsmPrinter::EmitString(const ConstantArray *CVA) const {
 550   unsigned NumElts = CVA->getNumOperands();
 551   if (NumElts) {
 552     // ML does not have escape sequences except '' for '.  It also has a maximum
 553     // string length of 255.
 554     unsigned len = 0;
 555     bool inString = false;
 556     for (unsigned i = 0; i < NumElts; i++) {
 557       int n = cast<ConstantInt>(CVA->getOperand(i))->getZExtValue() & 255;
 558       if (len == 0)
 559         O << "\tdb ";
 560
 561       if (n >= 32 && n <= 127) {
 562         if (!inString) {
 563           if (len > 0) {
 564             O << ",'";
 565             len += 2;
 566           } else {
 567             O << "'";
 568             len++;
 569           }
 570           inString = true;
 571         }
 572         if (n == '\'') {
 573           O << "'";
 574           len++;
 575         }
 576         O << char(n);
 577       } else {
 578         if (inString) {
 579           O << "'";
 580           len++;
 581           inString = false;
 582         }
 583         if (len > 0) {
 584           O << ",";
 585           len++;
 586         }
 587         O << n;
 588         len += 1 + (n > 9) + (n > 99);
 589       }
 590
 591       if (len > 60) {
 592         if (inString) {
 593           O << "'";
 594           inString = false;
 595         }
 596         O << "\n";
 597         len = 0;
 598       }
 599     }
 600
 601     if (len > 0) {
 602       if (inString)
 603         O << "'";
 604       O << "\n";
 605     }
 606   }
 607 }
 608
 609 // Include the auto-generated portion of the assembly writer.
 610 #include "X86GenAsmWriter1.inc"