lib/Target/Mips/AsmPrinter/MipsAsmPrinter.cpp

   1 //===-- MipsAsmPrinter.cpp - Mips LLVM assembly writer --------------------===//
   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 GAS-format MIPS assembly language.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #define DEBUG_TYPE "mips-asm-printer"
  16
  17 #include "Mips.h"
  18 #include "MipsSubtarget.h"
  19 #include "MipsInstrInfo.h"
  20 #include "MipsTargetMachine.h"
  21 #include "MipsMachineFunction.h"
  22 #include "llvm/Constants.h"
  23 #include "llvm/DerivedTypes.h"
  24 #include "llvm/Module.h"
  25 #include "llvm/CodeGen/AsmPrinter.h"
  26 #include "llvm/CodeGen/DwarfWriter.h"
  27 #include "llvm/CodeGen/MachineFunctionPass.h"
  28 #include "llvm/CodeGen/MachineConstantPool.h"
  29 #include "llvm/CodeGen/MachineFrameInfo.h"
  30 #include "llvm/CodeGen/MachineInstr.h"
  31 #include "llvm/MC/MCStreamer.h"
  32 #include "llvm/MC/MCAsmInfo.h"
  33 #include "llvm/MC/MCSymbol.h"
  34 #include "llvm/Target/TargetData.h"
  35 #include "llvm/Target/TargetLoweringObjectFile.h"
  36 #include "llvm/Target/TargetMachine.h"
  37 #include "llvm/Target/TargetOptions.h"
  38 #include "llvm/Target/TargetRegistry.h"
  39 #include "llvm/Support/ErrorHandling.h"
  40 #include "llvm/Support/Mangler.h"
  41 #include "llvm/ADT/Statistic.h"
  42 #include "llvm/ADT/StringExtras.h"
  43 #include "llvm/Support/Debug.h"
  44 #include "llvm/Support/CommandLine.h"
  45 #include "llvm/Support/FormattedStream.h"
  46 #include "llvm/Support/MathExtras.h"
  47 #include <cctype>
  48
  49 using namespace llvm;
  50
  51 STATISTIC(EmittedInsts, "Number of machine instrs printed");
  52
  53 namespace {
  54   class VISIBILITY_HIDDEN MipsAsmPrinter : public AsmPrinter {
  55     const MipsSubtarget *Subtarget;
  56   public:
  57     explicit MipsAsmPrinter(formatted_raw_ostream &O, TargetMachine &TM,
  58                             const MCAsmInfo *T, bool V)
  59       : AsmPrinter(O, TM, T, V) {
  60       Subtarget = &TM.getSubtarget<MipsSubtarget>();
  61     }
  62
  63     virtual const char *getPassName() const {
  64       return "Mips Assembly Printer";
  65     }
  66
  67     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
  68                          unsigned AsmVariant, const char *ExtraCode);
  69     void printOperand(const MachineInstr *MI, int opNum);
  70     void printUnsignedImm(const MachineInstr *MI, int opNum);
  71     void printMemOperand(const MachineInstr *MI, int opNum,
  72                          const char *Modifier = 0);
  73     void printFCCOperand(const MachineInstr *MI, int opNum,
  74                          const char *Modifier = 0);
  75     void PrintGlobalVariable(const GlobalVariable *GVar);
  76     void printSavedRegsBitmask(MachineFunction &MF);
  77     void printHex32(unsigned int Value);
  78
  79     const char *emitCurrentABIString();
  80     void emitFunctionStart(MachineFunction &MF);
  81     void emitFunctionEnd(MachineFunction &MF);
  82     void emitFrameDirective(MachineFunction &MF);
  83
  84     void printInstruction(const MachineInstr *MI);  // autogenerated.
  85     const char *getRegisterName(unsigned RegNo) const;
  86
  87     bool runOnMachineFunction(MachineFunction &F);
  88     bool doInitialization(Module &M);
  89   };
  90 } // end of anonymous namespace
  91
  92 #include "MipsGenAsmWriter.inc"
  93
  94 //===----------------------------------------------------------------------===//
  95 //
  96 //  Mips Asm Directives
  97 //
  98 //  -- Frame directive "frame Stackpointer, Stacksize, RARegister"
  99 //  Describe the stack frame.
 100 //
 101 //  -- Mask directives "(f)mask  bitmask, offset"
 102 //  Tells the assembler which registers are saved and where.
 103 //  bitmask - contain a little endian bitset indicating which registers are
 104 //            saved on function prologue (e.g. with a 0x80000000 mask, the
 105 //            assembler knows the register 31 (RA) is saved at prologue.
 106 //  offset  - the position before stack pointer subtraction indicating where
 107 //            the first saved register on prologue is located. (e.g. with a
 108 //
 109 //  Consider the following function prologue:
 110 //
 111 //    .frame  $fp,48,$ra
 112 //    .mask   0xc0000000,-8
 113 //       addiu $sp, $sp, -48
 114 //       sw $ra, 40($sp)
 115 //       sw $fp, 36($sp)
 116 //
 117 //    With a 0xc0000000 mask, the assembler knows the register 31 (RA) and
 118 //    30 (FP) are saved at prologue. As the save order on prologue is from
 119 //    left to right, RA is saved first. A -8 offset means that after the
 120 //    stack pointer subtration, the first register in the mask (RA) will be
 121 //    saved at address 48-8=40.
 122 //
 123 //===----------------------------------------------------------------------===//
 124
 125 //===----------------------------------------------------------------------===//
 126 // Mask directives
 127 //===----------------------------------------------------------------------===//
 128
 129 // Create a bitmask with all callee saved registers for CPU or Floating Point
 130 // registers. For CPU registers consider RA, GP and FP for saving if necessary.
 131 void MipsAsmPrinter::
 132 printSavedRegsBitmask(MachineFunction &MF)
 133 {
 134   const TargetRegisterInfo &RI = *TM.getRegisterInfo();
 135   MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
 136
 137   // CPU and FPU Saved Registers Bitmasks
 138   unsigned int CPUBitmask = 0;
 139   unsigned int FPUBitmask = 0;
 140
 141   // Set the CPU and FPU Bitmasks
 142   MachineFrameInfo *MFI = MF.getFrameInfo();
 143   const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
 144   for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
 145     unsigned RegNum = MipsRegisterInfo::getRegisterNumbering(CSI[i].getReg());
 146     if (CSI[i].getRegClass() == Mips::CPURegsRegisterClass)
 147       CPUBitmask |= (1 << RegNum);
 148     else
 149       FPUBitmask |= (1 << RegNum);
 150   }
 151
 152   // Return Address and Frame registers must also be set in CPUBitmask.
 153   if (RI.hasFP(MF))
 154     CPUBitmask |= (1 << MipsRegisterInfo::
 155                 getRegisterNumbering(RI.getFrameRegister(MF)));
 156
 157   if (MF.getFrameInfo()->hasCalls())
 158     CPUBitmask |= (1 << MipsRegisterInfo::
 159                 getRegisterNumbering(RI.getRARegister()));
 160
 161   // Print CPUBitmask
 162   O << "\t.mask \t"; printHex32(CPUBitmask); O << ','
 163     << MipsFI->getCPUTopSavedRegOff() << '\n';
 164
 165   // Print FPUBitmask
 166   O << "\t.fmask\t"; printHex32(FPUBitmask); O << ","
 167     << MipsFI->getFPUTopSavedRegOff() << '\n';
 168 }
 169
 170 // Print a 32 bit hex number with all numbers.
 171 void MipsAsmPrinter::
 172 printHex32(unsigned int Value)
 173 {
 174   O << "0x";
 175   for (int i = 7; i >= 0; i--)
 176     O << utohexstr( (Value & (0xF << (i*4))) >> (i*4) );
 177 }
 178
 179 //===----------------------------------------------------------------------===//
 180 // Frame and Set directives
 181 //===----------------------------------------------------------------------===//
 182
 183 /// Frame Directive
 184 void MipsAsmPrinter::emitFrameDirective(MachineFunction &MF) {
 185   const TargetRegisterInfo &RI = *TM.getRegisterInfo();
 186
 187   unsigned stackReg  = RI.getFrameRegister(MF);
 188   unsigned returnReg = RI.getRARegister();
 189   unsigned stackSize = MF.getFrameInfo()->getStackSize();
 190
 191
 192   O << "\t.frame\t" << '$' << LowercaseString(RI.get(stackReg).AsmName)
 193                     << ',' << stackSize << ','
 194                     << '$' << LowercaseString(RI.get(returnReg).AsmName)
 195                     << '\n';
 196 }
 197
 198 /// Emit Set directives.
 199 const char *MipsAsmPrinter::emitCurrentABIString() {
 200   switch(Subtarget->getTargetABI()) {
 201     case MipsSubtarget::O32:  return "abi32";
 202     case MipsSubtarget::O64:  return "abiO64";
 203     case MipsSubtarget::N32:  return "abiN32";
 204     case MipsSubtarget::N64:  return "abi64";
 205     case MipsSubtarget::EABI: return "eabi32"; // TODO: handle eabi64
 206     default: break;
 207   }
 208
 209   llvm_unreachable("Unknown Mips ABI");
 210   return NULL;
 211 }
 212
 213 /// Emit the directives used by GAS on the start of functions
 214 void MipsAsmPrinter::emitFunctionStart(MachineFunction &MF) {
 215   // Print out the label for the function.
 216   const Function *F = MF.getFunction();
 217   OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(F, Mang, TM));
 218
 219   // 2 bits aligned
 220   EmitAlignment(MF.getAlignment(), F);
 221
 222   O << "\t.globl\t"  << CurrentFnName << '\n';
 223   O << "\t.ent\t"    << CurrentFnName << '\n';
 224
 225   printVisibility(CurrentFnName, F->getVisibility());
 226
 227   if ((MAI->hasDotTypeDotSizeDirective()) && Subtarget->isLinux())
 228     O << "\t.type\t"   << CurrentFnName << ", @function\n";
 229
 230   O << CurrentFnName << ":\n";
 231
 232   emitFrameDirective(MF);
 233   printSavedRegsBitmask(MF);
 234
 235   O << '\n';
 236 }
 237
 238 /// Emit the directives used by GAS on the end of functions
 239 void MipsAsmPrinter::emitFunctionEnd(MachineFunction &MF) {
 240   // There are instruction for this macros, but they must
 241   // always be at the function end, and we can't emit and
 242   // break with BB logic.
 243   O << "\t.set\tmacro\n";
 244   O << "\t.set\treorder\n";
 245
 246   O << "\t.end\t" << CurrentFnName << '\n';
 247   if (MAI->hasDotTypeDotSizeDirective() && !Subtarget->isLinux())
 248     O << "\t.size\t" << CurrentFnName << ", .-" << CurrentFnName << '\n';
 249 }
 250
 251 /// runOnMachineFunction - This uses the printMachineInstruction()
 252 /// method to print assembly for each instruction.
 253 bool MipsAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
 254   this->MF = &MF;
 255
 256   SetupMachineFunction(MF);
 257
 258   // Print out constants referenced by the function
 259   EmitConstantPool(MF.getConstantPool());
 260
 261   // Print out jump tables referenced by the function
 262   EmitJumpTableInfo(MF.getJumpTableInfo(), MF);
 263
 264   O << "\n\n";
 265
 266   // Emit the function start directives
 267   emitFunctionStart(MF);
 268
 269   // Print out code for the function.
 270   for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
 271        I != E; ++I) {
 272
 273     // Print a label for the basic block.
 274     if (I != MF.begin()) {
 275       EmitBasicBlockStart(I);
 276       O << '\n';
 277     }
 278
 279     for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
 280          II != E; ++II) {
 281       processDebugLoc(II->getDebugLoc());
 282
 283       // Print the assembly for the instruction.
 284       printInstruction(II);
 285
 286       if (VerboseAsm && !II->getDebugLoc().isUnknown())
 287         EmitComments(*II);
 288       O << '\n';
 289
 290       ++EmittedInsts;
 291     }
 292
 293     // Each Basic Block is separated by a newline
 294     O << '\n';
 295   }
 296
 297   // Emit function end directives
 298   emitFunctionEnd(MF);
 299
 300   // We didn't modify anything.
 301   return false;
 302 }
 303
 304 // Print out an operand for an inline asm expression.
 305 bool MipsAsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
 306                                      unsigned AsmVariant,const char *ExtraCode){
 307   // Does this asm operand have a single letter operand modifier?
 308   if (ExtraCode && ExtraCode[0])
 309     return true; // Unknown modifier.
 310
 311   printOperand(MI, OpNo);
 312   return false;
 313 }
 314
 315 void MipsAsmPrinter::printOperand(const MachineInstr *MI, int opNum) {
 316   const MachineOperand &MO = MI->getOperand(opNum);
 317   const TargetRegisterInfo  &RI = *TM.getRegisterInfo();
 318   bool closeP = false;
 319
 320   if (MO.getTargetFlags())
 321     closeP = true;
 322
 323   switch(MO.getTargetFlags()) {
 324   case MipsII::MO_GPREL:    O << "%gp_rel("; break;
 325   case MipsII::MO_GOT_CALL: O << "%call16("; break;
 326   case MipsII::MO_GOT:
 327     if (MI->getOpcode() == Mips::LW)
 328       O << "%got(";
 329     else
 330       O << "%lo(";
 331     break;
 332   case MipsII::MO_ABS_HILO:
 333     if (MI->getOpcode() == Mips::LUi)
 334       O << "%hi(";
 335     else
 336       O << "%lo(";
 337     break;
 338   }
 339
 340   switch (MO.getType())
 341   {
 342     case MachineOperand::MO_Register:
 343       if (TargetRegisterInfo::isPhysicalRegister(MO.getReg()))
 344         O << '$' << LowercaseString (RI.get(MO.getReg()).AsmName);
 345       else
 346         O << '$' << MO.getReg();
 347       break;
 348
 349     case MachineOperand::MO_Immediate:
 350       O << (short int)MO.getImm();
 351       break;
 352
 353     case MachineOperand::MO_MachineBasicBlock:
 354       GetMBBSymbol(MO.getMBB()->getNumber())->print(O, MAI);
 355       return;
 356
 357     case MachineOperand::MO_GlobalAddress:
 358       O << Mang->getMangledName(MO.getGlobal());
 359       break;
 360
 361     case MachineOperand::MO_ExternalSymbol:
 362       O << MO.getSymbolName();
 363       break;
 364
 365     case MachineOperand::MO_JumpTableIndex:
 366       O << MAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
 367       << '_' << MO.getIndex();
 368       break;
 369
 370     case MachineOperand::MO_ConstantPoolIndex:
 371       O << MAI->getPrivateGlobalPrefix() << "CPI"
 372         << getFunctionNumber() << "_" << MO.getIndex();
 373       break;
 374
 375     default:
 376       llvm_unreachable("<unknown operand type>");
 377   }
 378
 379   if (closeP) O << ")";
 380 }
 381
 382 void MipsAsmPrinter::printUnsignedImm(const MachineInstr *MI, int opNum) {
 383   const MachineOperand &MO = MI->getOperand(opNum);
 384   if (MO.getType() == MachineOperand::MO_Immediate)
 385     O << (unsigned short int)MO.getImm();
 386   else
 387     printOperand(MI, opNum);
 388 }
 389
 390 void MipsAsmPrinter::
 391 printMemOperand(const MachineInstr *MI, int opNum, const char *Modifier) {
 392   // when using stack locations for not load/store instructions
 393   // print the same way as all normal 3 operand instructions.
 394   if (Modifier && !strcmp(Modifier, "stackloc")) {
 395     printOperand(MI, opNum+1);
 396     O << ", ";
 397     printOperand(MI, opNum);
 398     return;
 399   }
 400
 401   // Load/Store memory operands -- imm($reg)
 402   // If PIC target the target is loaded as the
 403   // pattern lw $25,%call16($28)
 404   printOperand(MI, opNum);
 405   O << "(";
 406   printOperand(MI, opNum+1);
 407   O << ")";
 408 }
 409
 410 void MipsAsmPrinter::
 411 printFCCOperand(const MachineInstr *MI, int opNum, const char *Modifier) {
 412   const MachineOperand& MO = MI->getOperand(opNum);
 413   O << Mips::MipsFCCToString((Mips::CondCode)MO.getImm());
 414 }
 415
 416 bool MipsAsmPrinter::doInitialization(Module &M) {
 417   // FIXME: Use SwitchSection.
 418
 419   // Tell the assembler which ABI we are using
 420   O << "\t.section .mdebug." << emitCurrentABIString() << '\n';
 421
 422   // TODO: handle O64 ABI
 423   if (Subtarget->isABI_EABI())
 424     O << "\t.section .gcc_compiled_long" <<
 425       (Subtarget->isGP32bit() ? "32" : "64") << '\n';
 426
 427   // return to previous section
 428   O << "\t.previous" << '\n';
 429
 430   return AsmPrinter::doInitialization(M);
 431 }
 432
 433 void MipsAsmPrinter::PrintGlobalVariable(const GlobalVariable *GVar) {
 434   const TargetData *TD = TM.getTargetData();
 435
 436   if (!GVar->hasInitializer())
 437     return;   // External global require no code
 438
 439   // Check to see if this is a special global used by LLVM, if so, emit it.
 440   if (EmitSpecialLLVMGlobal(GVar))
 441     return;
 442
 443   O << "\n\n";
 444   std::string name = Mang->getMangledName(GVar);
 445   Constant *C = GVar->getInitializer();
 446   const Type *CTy = C->getType();
 447   unsigned Size = TD->getTypeAllocSize(CTy);
 448   const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
 449   bool printSizeAndType = true;
 450
 451   // A data structure or array is aligned in memory to the largest
 452   // alignment boundary required by any data type inside it (this matches
 453   // the Preferred Type Alignment). For integral types, the alignment is
 454   // the type size.
 455   unsigned Align;
 456   if (CTy->getTypeID() == Type::IntegerTyID ||
 457       CTy->getTypeID() == Type::VoidTyID) {
 458     assert(!(Size & (Size-1)) && "Alignment is not a power of two!");
 459     Align = Log2_32(Size);
 460   } else
 461     Align = TD->getPreferredTypeAlignmentShift(CTy);
 462
 463   printVisibility(name, GVar->getVisibility());
 464
 465   OutStreamer.SwitchSection(getObjFileLowering().SectionForGlobal(GVar, Mang,
 466                                                                   TM));
 467
 468   if (C->isNullValue() && !GVar->hasSection()) {
 469     if (!GVar->isThreadLocal() &&
 470         (GVar->hasLocalLinkage() || GVar->isWeakForLinker())) {
 471       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
 472
 473       if (GVar->hasLocalLinkage())
 474         O << "\t.local\t" << name << '\n';
 475
 476       O << MAI->getCOMMDirective() << name << ',' << Size;
 477       if (MAI->getCOMMDirectiveTakesAlignment())
 478         O << ',' << (1 << Align);
 479
 480       O << '\n';
 481       return;
 482     }
 483   }
 484   switch (GVar->getLinkage()) {
 485    case GlobalValue::LinkOnceAnyLinkage:
 486    case GlobalValue::LinkOnceODRLinkage:
 487    case GlobalValue::CommonLinkage:
 488    case GlobalValue::WeakAnyLinkage:
 489    case GlobalValue::WeakODRLinkage:
 490     // FIXME: Verify correct for weak.
 491     // Nonnull linkonce -> weak
 492     O << "\t.weak " << name << '\n';
 493     break;
 494    case GlobalValue::AppendingLinkage:
 495     // FIXME: appending linkage variables should go into a section of their name
 496     // or something.  For now, just emit them as external.
 497    case GlobalValue::ExternalLinkage:
 498     // If external or appending, declare as a global symbol
 499     O << MAI->getGlobalDirective() << name << '\n';
 500     // Fall Through
 501    case GlobalValue::PrivateLinkage:
 502    case GlobalValue::LinkerPrivateLinkage:
 503    case GlobalValue::InternalLinkage:
 504     if (CVA && CVA->isCString())
 505       printSizeAndType = false;
 506     break;
 507    case GlobalValue::GhostLinkage:
 508     llvm_unreachable("Should not have any unmaterialized functions!");
 509    case GlobalValue::DLLImportLinkage:
 510     llvm_unreachable("DLLImport linkage is not supported by this target!");
 511    case GlobalValue::DLLExportLinkage:
 512     llvm_unreachable("DLLExport linkage is not supported by this target!");
 513    default:
 514     llvm_unreachable("Unknown linkage type!");
 515   }
 516
 517   EmitAlignment(Align, GVar);
 518
 519   if (MAI->hasDotTypeDotSizeDirective() && printSizeAndType) {
 520     O << "\t.type " << name << ",@object\n";
 521     O << "\t.size " << name << ',' << Size << '\n';
 522   }
 523
 524   O << name << ":\n";
 525   EmitGlobalConstant(C);
 526 }
 527
 528
 529 // Force static initialization.
 530 extern "C" void LLVMInitializeMipsAsmPrinter() {
 531   RegisterAsmPrinter<MipsAsmPrinter> X(TheMipsTarget);
 532   RegisterAsmPrinter<MipsAsmPrinter> Y(TheMipselTarget);
 533 }