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/Target/TargetAsmInfo.h"
  32 #include "llvm/Target/TargetData.h"
  33 #include "llvm/Target/TargetMachine.h"
  34 #include "llvm/Target/TargetOptions.h"
  35 #include "llvm/Support/Mangler.h"
  36 #include "llvm/ADT/Statistic.h"
  37 #include "llvm/ADT/StringExtras.h"
  38 #include "llvm/Support/Debug.h"
  39 #include "llvm/Support/CommandLine.h"
  40 #include "llvm/Support/MathExtras.h"
  41 #include "llvm/Support/raw_ostream.h"
  42 #include <cctype>
  43
  44 using namespace llvm;
  45
  46 STATISTIC(EmittedInsts, "Number of machine instrs printed");
  47
  48 namespace {
  49   class VISIBILITY_HIDDEN MipsAsmPrinter : public AsmPrinter {
  50     const MipsSubtarget *Subtarget;
  51   public:
  52     MipsAsmPrinter(raw_ostream &O, MipsTargetMachine &TM,
  53                    const TargetAsmInfo *T, bool F, bool V)
  54       : AsmPrinter(O, TM, T, F, V) {
  55       Subtarget = &TM.getSubtarget<MipsSubtarget>();
  56     }
  57
  58     virtual const char *getPassName() const {
  59       return "Mips Assembly Printer";
  60     }
  61
  62     bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
  63                          unsigned AsmVariant, const char *ExtraCode);
  64     void printOperand(const MachineInstr *MI, int opNum);
  65     void printUnsignedImm(const MachineInstr *MI, int opNum);
  66     void printMemOperand(const MachineInstr *MI, int opNum,
  67                          const char *Modifier = 0);
  68     void printFCCOperand(const MachineInstr *MI, int opNum,
  69                          const char *Modifier = 0);
  70     void printModuleLevelGV(const GlobalVariable* GVar);
  71     void printSavedRegsBitmask(MachineFunction &MF);
  72     void printHex32(unsigned int Value);
  73
  74     const char *emitCurrentABIString(void);
  75     void emitFunctionStart(MachineFunction &MF);
  76     void emitFunctionEnd(MachineFunction &MF);
  77     void emitFrameDirective(MachineFunction &MF);
  78
  79     bool printInstruction(const MachineInstr *MI);  // autogenerated.
  80     bool runOnMachineFunction(MachineFunction &F);
  81     bool doInitialization(Module &M);
  82     bool doFinalization(Module &M);
  83   };
  84 } // end of anonymous namespace
  85
  86 #include "MipsGenAsmWriter.inc"
  87
  88 /// createMipsCodePrinterPass - Returns a pass that prints the MIPS
  89 /// assembly code for a MachineFunction to the given output stream,
  90 /// using the given target machine description.  This should work
  91 /// regardless of whether the function is in SSA form.
  92 FunctionPass *llvm::createMipsCodePrinterPass(raw_ostream &o,
  93                                               MipsTargetMachine &tm,
  94                                               bool fast, bool verbose) {
  95   return new MipsAsmPrinter(o, tm, tm.getTargetAsmInfo(), fast, verbose);
  96 }
  97
  98 //===----------------------------------------------------------------------===//
  99 //
 100 //  Mips Asm Directives
 101 //
 102 //  -- Frame directive "frame Stackpointer, Stacksize, RARegister"
 103 //  Describe the stack frame.
 104 //
 105 //  -- Mask directives "(f)mask  bitmask, offset"
 106 //  Tells the assembler which registers are saved and where.
 107 //  bitmask - contain a little endian bitset indicating which registers are
 108 //            saved on function prologue (e.g. with a 0x80000000 mask, the
 109 //            assembler knows the register 31 (RA) is saved at prologue.
 110 //  offset  - the position before stack pointer subtraction indicating where
 111 //            the first saved register on prologue is located. (e.g. with a
 112 //
 113 //  Consider the following function prologue:
 114 //
 115 //    .frame  $fp,48,$ra
 116 //    .mask   0xc0000000,-8
 117 //       addiu $sp, $sp, -48
 118 //       sw $ra, 40($sp)
 119 //       sw $fp, 36($sp)
 120 //
 121 //    With a 0xc0000000 mask, the assembler knows the register 31 (RA) and
 122 //    30 (FP) are saved at prologue. As the save order on prologue is from
 123 //    left to right, RA is saved first. A -8 offset means that after the
 124 //    stack pointer subtration, the first register in the mask (RA) will be
 125 //    saved at address 48-8=40.
 126 //
 127 //===----------------------------------------------------------------------===//
 128
 129 //===----------------------------------------------------------------------===//
 130 // Mask directives
 131 //===----------------------------------------------------------------------===//
 132
 133 // Create a bitmask with all callee saved registers for CPU or Floating Point
 134 // registers. For CPU registers consider RA, GP and FP for saving if necessary.
 135 void MipsAsmPrinter::
 136 printSavedRegsBitmask(MachineFunction &MF)
 137 {
 138   const TargetRegisterInfo &RI = *TM.getRegisterInfo();
 139   MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
 140
 141   // CPU and FPU Saved Registers Bitmasks
 142   unsigned int CPUBitmask = 0;
 143   unsigned int FPUBitmask = 0;
 144
 145   // Set the CPU and FPU Bitmasks
 146   MachineFrameInfo *MFI = MF.getFrameInfo();
 147   const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
 148   for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
 149     unsigned RegNum = MipsRegisterInfo::getRegisterNumbering(CSI[i].getReg());
 150     if (CSI[i].getRegClass() == Mips::CPURegsRegisterClass)
 151       CPUBitmask |= (1 << RegNum);
 152     else
 153       FPUBitmask |= (1 << RegNum);
 154   }
 155
 156   // Return Address and Frame registers must also be set in CPUBitmask.
 157   if (RI.hasFP(MF))
 158     CPUBitmask |= (1 << MipsRegisterInfo::
 159                 getRegisterNumbering(RI.getFrameRegister(MF)));
 160
 161   if (MF.getFrameInfo()->hasCalls())
 162     CPUBitmask |= (1 << MipsRegisterInfo::
 163                 getRegisterNumbering(RI.getRARegister()));
 164
 165   // Print CPUBitmask
 166   O << "\t.mask \t"; printHex32(CPUBitmask); O << ','
 167     << MipsFI->getCPUTopSavedRegOff() << '\n';
 168
 169   // Print FPUBitmask
 170   O << "\t.fmask\t"; printHex32(FPUBitmask); O << ","
 171     << MipsFI->getFPUTopSavedRegOff() << '\n';
 172 }
 173
 174 // Print a 32 bit hex number with all numbers.
 175 void MipsAsmPrinter::
 176 printHex32(unsigned int Value)
 177 {
 178   O << "0x";
 179   for (int i = 7; i >= 0; i--)
 180     O << utohexstr( (Value & (0xF << (i*4))) >> (i*4) );
 181 }
 182
 183 //===----------------------------------------------------------------------===//
 184 // Frame and Set directives
 185 //===----------------------------------------------------------------------===//
 186
 187 /// Frame Directive
 188 void MipsAsmPrinter::
 189 emitFrameDirective(MachineFunction &MF)
 190 {
 191   const TargetRegisterInfo &RI = *TM.getRegisterInfo();
 192
 193   unsigned stackReg  = RI.getFrameRegister(MF);
 194   unsigned returnReg = RI.getRARegister();
 195   unsigned stackSize = MF.getFrameInfo()->getStackSize();
 196
 197
 198   O << "\t.frame\t" << '$' << LowercaseString(RI.get(stackReg).AsmName)
 199                     << ',' << stackSize << ','
 200                     << '$' << LowercaseString(RI.get(returnReg).AsmName)
 201                     << '\n';
 202 }
 203
 204 /// Emit Set directives.
 205 const char * MipsAsmPrinter::
 206 emitCurrentABIString(void)
 207 {
 208   switch(Subtarget->getTargetABI()) {
 209     case MipsSubtarget::O32:  return "abi32";
 210     case MipsSubtarget::O64:  return "abiO64";
 211     case MipsSubtarget::N32:  return "abiN32";
 212     case MipsSubtarget::N64:  return "abi64";
 213     case MipsSubtarget::EABI: return "eabi32"; // TODO: handle eabi64
 214     default: break;
 215   }
 216
 217   assert(0 && "Unknown Mips ABI");
 218   return NULL;
 219 }
 220
 221 /// Emit the directives used by GAS on the start of functions
 222 void MipsAsmPrinter::
 223 emitFunctionStart(MachineFunction &MF)
 224 {
 225   // Print out the label for the function.
 226   const Function *F = MF.getFunction();
 227   SwitchToSection(TAI->SectionForGlobal(F));
 228
 229   // 2 bits aligned
 230   EmitAlignment(2, F);
 231
 232   O << "\t.globl\t"  << CurrentFnName << '\n';
 233   O << "\t.ent\t"    << CurrentFnName << '\n';
 234
 235   printVisibility(CurrentFnName, F->getVisibility());
 236
 237   if ((TAI->hasDotTypeDotSizeDirective()) && Subtarget->isLinux())
 238     O << "\t.type\t"   << CurrentFnName << ", @function\n";
 239
 240   O << CurrentFnName << ":\n";
 241
 242   emitFrameDirective(MF);
 243   printSavedRegsBitmask(MF);
 244
 245   O << '\n';
 246 }
 247
 248 /// Emit the directives used by GAS on the end of functions
 249 void MipsAsmPrinter::
 250 emitFunctionEnd(MachineFunction &MF)
 251 {
 252   // There are instruction for this macros, but they must
 253   // always be at the function end, and we can't emit and
 254   // break with BB logic.
 255   O << "\t.set\tmacro\n";
 256   O << "\t.set\treorder\n";
 257
 258   O << "\t.end\t" << CurrentFnName << '\n';
 259   if (TAI->hasDotTypeDotSizeDirective() && !Subtarget->isLinux())
 260     O << "\t.size\t" << CurrentFnName << ", .-" << CurrentFnName << '\n';
 261 }
 262
 263 /// runOnMachineFunction - This uses the printMachineInstruction()
 264 /// method to print assembly for each instruction.
 265 bool MipsAsmPrinter::
 266 runOnMachineFunction(MachineFunction &MF)
 267 {
 268   this->MF = &MF;
 269
 270   SetupMachineFunction(MF);
 271
 272   // Print out constants referenced by the function
 273   EmitConstantPool(MF.getConstantPool());
 274
 275   // Print out jump tables referenced by the function
 276   EmitJumpTableInfo(MF.getJumpTableInfo(), MF);
 277
 278   O << "\n\n";
 279
 280   // Emit the function start directives
 281   emitFunctionStart(MF);
 282
 283   // Print out code for the function.
 284   for (MachineFunction::const_iterator I = MF.begin(), E = MF.end();
 285        I != E; ++I) {
 286
 287     // Print a label for the basic block.
 288     if (I != MF.begin()) {
 289       printBasicBlockLabel(I, true, true);
 290       O << '\n';
 291     }
 292
 293     for (MachineBasicBlock::const_iterator II = I->begin(), E = I->end();
 294          II != E; ++II) {
 295       // Print the assembly for the instruction.
 296       printInstruction(II);
 297       ++EmittedInsts;
 298     }
 299
 300     // Each Basic Block is separated by a newline
 301     O << '\n';
 302   }
 303
 304   // Emit function end directives
 305   emitFunctionEnd(MF);
 306
 307   // We didn't modify anything.
 308   return false;
 309 }
 310
 311 // Print out an operand for an inline asm expression.
 312 bool MipsAsmPrinter::
 313 PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
 314                 unsigned AsmVariant, const char *ExtraCode)
 315 {
 316   // Does this asm operand have a single letter operand modifier?
 317   if (ExtraCode && ExtraCode[0])
 318     return true; // Unknown modifier.
 319
 320   printOperand(MI, OpNo);
 321   return false;
 322 }
 323
 324 void MipsAsmPrinter::
 325 printOperand(const MachineInstr *MI, int opNum)
 326 {
 327   const MachineOperand &MO = MI->getOperand(opNum);
 328   const TargetRegisterInfo  &RI = *TM.getRegisterInfo();
 329   bool closeP = false;
 330   bool isPIC = (TM.getRelocationModel() == Reloc::PIC_);
 331   bool isCodeLarge = (TM.getCodeModel() == CodeModel::Large);
 332
 333   // %hi and %lo used on mips gas to load global addresses on
 334   // static code. %got is used to load global addresses when
 335   // using PIC_. %call16 is used to load direct call targets
 336   // on PIC_ and small code size. %call_lo and %call_hi load
 337   // direct call targets on PIC_ and large code size.
 338   if (MI->getOpcode() == Mips::LUi && !MO.isReg() && !MO.isImm()) {
 339     if ((isPIC) && (isCodeLarge))
 340       O << "%call_hi(";
 341     else
 342       O << "%hi(";
 343     closeP = true;
 344   } else if ((MI->getOpcode() == Mips::ADDiu) && !MO.isReg() && !MO.isImm()) {
 345     const MachineOperand &firstMO = MI->getOperand(opNum-1);
 346     if (firstMO.getReg() == Mips::GP)
 347       O << "%gp_rel(";
 348     else
 349       O << "%lo(";
 350     closeP = true;
 351   } else if ((isPIC) && (MI->getOpcode() == Mips::LW) &&
 352              (!MO.isReg()) && (!MO.isImm())) {
 353     const MachineOperand &firstMO = MI->getOperand(opNum-1);
 354     const MachineOperand &lastMO  = MI->getOperand(opNum+1);
 355     if ((firstMO.isReg()) && (lastMO.isReg())) {
 356       if ((firstMO.getReg() == Mips::T9) && (lastMO.getReg() == Mips::GP)
 357           && (!isCodeLarge))
 358         O << "%call16(";
 359       else if ((firstMO.getReg() != Mips::T9) && (lastMO.getReg() == Mips::GP))
 360         O << "%got(";
 361       else if ((firstMO.getReg() == Mips::T9) && (lastMO.getReg() != Mips::GP)
 362                && (isCodeLarge))
 363         O << "%call_lo(";
 364       closeP = true;
 365     }
 366   }
 367
 368   switch (MO.getType())
 369   {
 370     case MachineOperand::MO_Register:
 371       if (TargetRegisterInfo::isPhysicalRegister(MO.getReg()))
 372         O << '$' << LowercaseString (RI.get(MO.getReg()).AsmName);
 373       else
 374         O << '$' << MO.getReg();
 375       break;
 376
 377     case MachineOperand::MO_Immediate:
 378       O << (short int)MO.getImm();
 379       break;
 380
 381     case MachineOperand::MO_MachineBasicBlock:
 382       printBasicBlockLabel(MO.getMBB());
 383       return;
 384
 385     case MachineOperand::MO_GlobalAddress:
 386       {
 387         const GlobalValue *GV = MO.getGlobal();
 388         O << Mang->getValueName(GV);
 389       }
 390       break;
 391
 392     case MachineOperand::MO_ExternalSymbol:
 393       O << MO.getSymbolName();
 394       break;
 395
 396     case MachineOperand::MO_JumpTableIndex:
 397       O << TAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber()
 398       << '_' << MO.getIndex();
 399       break;
 400
 401     case MachineOperand::MO_ConstantPoolIndex:
 402       O << TAI->getPrivateGlobalPrefix() << "CPI"
 403         << getFunctionNumber() << "_" << MO.getIndex();
 404       break;
 405
 406     default:
 407       O << "<unknown operand type>"; abort (); break;
 408   }
 409
 410   if (closeP) O << ")";
 411 }
 412
 413 void MipsAsmPrinter::
 414 printUnsignedImm(const MachineInstr *MI, int opNum)
 415 {
 416   const MachineOperand &MO = MI->getOperand(opNum);
 417   if (MO.getType() == MachineOperand::MO_Immediate)
 418     O << (unsigned short int)MO.getImm();
 419   else
 420     printOperand(MI, opNum);
 421 }
 422
 423 void MipsAsmPrinter::
 424 printMemOperand(const MachineInstr *MI, int opNum, const char *Modifier)
 425 {
 426   // when using stack locations for not load/store instructions
 427   // print the same way as all normal 3 operand instructions.
 428   if (Modifier && !strcmp(Modifier, "stackloc")) {
 429     printOperand(MI, opNum+1);
 430     O << ", ";
 431     printOperand(MI, opNum);
 432     return;
 433   }
 434
 435   // Load/Store memory operands -- imm($reg)
 436   // If PIC target the target is loaded as the
 437   // pattern lw $25,%call16($28)
 438   printOperand(MI, opNum);
 439   O << "(";
 440   printOperand(MI, opNum+1);
 441   O << ")";
 442 }
 443
 444 void MipsAsmPrinter::
 445 printFCCOperand(const MachineInstr *MI, int opNum, const char *Modifier)
 446 {
 447   const MachineOperand& MO = MI->getOperand(opNum);
 448   O << Mips::MipsFCCToString((Mips::CondCode)MO.getImm());
 449 }
 450
 451 bool MipsAsmPrinter::
 452 doInitialization(Module &M)
 453 {
 454   Mang = new Mangler(M, "", TAI->getPrivateGlobalPrefix());
 455
 456   // Tell the assembler which ABI we are using
 457   O << "\t.section .mdebug." << emitCurrentABIString() << '\n';
 458
 459   // TODO: handle O64 ABI
 460   if (Subtarget->isABI_EABI())
 461     O << "\t.section .gcc_compiled_long" <<
 462       (Subtarget->isGP32bit() ? "32" : "64") << '\n';
 463
 464   // return to previous section
 465   O << "\t.previous" << '\n';
 466
 467   return false; // success
 468 }
 469
 470 void MipsAsmPrinter::
 471 printModuleLevelGV(const GlobalVariable* GVar) {
 472   const TargetData *TD = TM.getTargetData();
 473
 474   if (!GVar->hasInitializer())
 475     return;   // External global require no code
 476
 477   // Check to see if this is a special global used by LLVM, if so, emit it.
 478   if (EmitSpecialLLVMGlobal(GVar))
 479     return;
 480
 481   O << "\n\n";
 482   std::string name = Mang->getValueName(GVar);
 483   Constant *C = GVar->getInitializer();
 484   const Type *CTy = C->getType();
 485   unsigned Size = TD->getTypePaddedSize(CTy);
 486   const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
 487   bool printSizeAndType = true;
 488
 489   // A data structure or array is aligned in memory to the largest
 490   // alignment boundary required by any data type inside it (this matches
 491   // the Preferred Type Alignment). For integral types, the alignment is
 492   // the type size.
 493   unsigned Align;
 494   if (CTy->getTypeID() == Type::IntegerTyID ||
 495       CTy->getTypeID() == Type::VoidTyID) {
 496     assert(!(Size & (Size-1)) && "Alignment is not a power of two!");
 497     Align = Log2_32(Size);
 498   } else
 499     Align = TD->getPreferredTypeAlignmentShift(CTy);
 500
 501   printVisibility(name, GVar->getVisibility());
 502
 503   SwitchToSection(TAI->SectionForGlobal(GVar));
 504
 505   if (C->isNullValue() && !GVar->hasSection()) {
 506     if (!GVar->isThreadLocal() &&
 507         (GVar->hasLocalLinkage() || GVar->isWeakForLinker())) {
 508       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
 509
 510       if (GVar->hasLocalLinkage())
 511         O << "\t.local\t" << name << '\n';
 512
 513       O << TAI->getCOMMDirective() << name << ',' << Size;
 514       if (TAI->getCOMMDirectiveTakesAlignment())
 515         O << ',' << (1 << Align);
 516
 517       O << '\n';
 518       return;
 519     }
 520   }
 521   switch (GVar->getLinkage()) {
 522    case GlobalValue::LinkOnceAnyLinkage:
 523    case GlobalValue::LinkOnceODRLinkage:
 524    case GlobalValue::CommonLinkage:
 525    case GlobalValue::WeakAnyLinkage:
 526    case GlobalValue::WeakODRLinkage:
 527     // FIXME: Verify correct for weak.
 528     // Nonnull linkonce -> weak
 529     O << "\t.weak " << name << '\n';
 530     break;
 531    case GlobalValue::AppendingLinkage:
 532     // FIXME: appending linkage variables should go into a section of their name
 533     // or something.  For now, just emit them as external.
 534    case GlobalValue::ExternalLinkage:
 535     // If external or appending, declare as a global symbol
 536     O << TAI->getGlobalDirective() << name << '\n';
 537     // Fall Through
 538    case GlobalValue::PrivateLinkage:
 539    case GlobalValue::InternalLinkage:
 540     if (CVA && CVA->isCString())
 541       printSizeAndType = false;
 542     break;
 543    case GlobalValue::GhostLinkage:
 544     cerr << "Should not have any unmaterialized functions!\n";
 545     abort();
 546    case GlobalValue::DLLImportLinkage:
 547     cerr << "DLLImport linkage is not supported by this target!\n";
 548     abort();
 549    case GlobalValue::DLLExportLinkage:
 550     cerr << "DLLExport linkage is not supported by this target!\n";
 551     abort();
 552    default:
 553     assert(0 && "Unknown linkage type!");
 554   }
 555
 556   EmitAlignment(Align, GVar);
 557
 558   if (TAI->hasDotTypeDotSizeDirective() && printSizeAndType) {
 559     O << "\t.type " << name << ",@object\n";
 560     O << "\t.size " << name << ',' << Size << '\n';
 561   }
 562
 563   O << name << ":\n";
 564   EmitGlobalConstant(C);
 565 }
 566
 567 bool MipsAsmPrinter::
 568 doFinalization(Module &M)
 569 {
 570   // Print out module-level global variables here.
 571   for (Module::const_global_iterator I = M.global_begin(),
 572          E = M.global_end(); I != E; ++I)
 573     printModuleLevelGV(I);
 574
 575   O << '\n';
 576
 577   return AsmPrinter::doFinalization(M);
 578 }