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      1 //===-- PTXAsmPrinter.cpp - PTX 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 PTX assembly language.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #define DEBUG_TYPE "ptx-asm-printer"
     16 
     17 #include "PTX.h"
     18 #include "PTXAsmPrinter.h"
     19 #include "PTXMachineFunctionInfo.h"
     20 #include "PTXParamManager.h"
     21 #include "PTXRegisterInfo.h"
     22 #include "PTXTargetMachine.h"
     23 #include "llvm/Argument.h"
     24 #include "llvm/DerivedTypes.h"
     25 #include "llvm/Function.h"
     26 #include "llvm/Module.h"
     27 #include "llvm/ADT/SmallString.h"
     28 #include "llvm/ADT/StringExtras.h"
     29 #include "llvm/ADT/Twine.h"
     30 #include "llvm/Analysis/DebugInfo.h"
     31 #include "llvm/CodeGen/AsmPrinter.h"
     32 #include "llvm/CodeGen/MachineFrameInfo.h"
     33 #include "llvm/CodeGen/MachineInstr.h"
     34 #include "llvm/CodeGen/MachineRegisterInfo.h"
     35 #include "llvm/MC/MCContext.h"
     36 #include "llvm/MC/MCExpr.h"
     37 #include "llvm/MC/MCInst.h"
     38 #include "llvm/MC/MCStreamer.h"
     39 #include "llvm/MC/MCSymbol.h"
     40 #include "llvm/Target/Mangler.h"
     41 #include "llvm/Target/TargetLoweringObjectFile.h"
     42 #include "llvm/Support/CommandLine.h"
     43 #include "llvm/Support/Debug.h"
     44 #include "llvm/Support/ErrorHandling.h"
     45 #include "llvm/Support/MathExtras.h"
     46 #include "llvm/Support/Path.h"
     47 #include "llvm/Support/TargetRegistry.h"
     48 #include "llvm/Support/raw_ostream.h"
     49 
     50 using namespace llvm;
     51 
     52 static const char PARAM_PREFIX[] = "__param_";
     53 static const char RETURN_PREFIX[] = "__ret_";
     54 
     55 static const char *getRegisterTypeName(unsigned RegNo,
     56                                        const MachineRegisterInfo& MRI) {
     57   const TargetRegisterClass *TRC = MRI.getRegClass(RegNo);
     58 
     59 #define TEST_REGCLS(cls, clsstr) \
     60   if (PTX::cls ## RegisterClass == TRC) return # clsstr;
     61 
     62   TEST_REGCLS(RegPred, pred);
     63   TEST_REGCLS(RegI16, b16);
     64   TEST_REGCLS(RegI32, b32);
     65   TEST_REGCLS(RegI64, b64);
     66   TEST_REGCLS(RegF32, b32);
     67   TEST_REGCLS(RegF64, b64);
     68 #undef TEST_REGCLS
     69 
     70   llvm_unreachable("Not in any register class!");
     71   return NULL;
     72 }
     73 
     74 static const char *getStateSpaceName(unsigned addressSpace) {
     75   switch (addressSpace) {
     76   default: llvm_unreachable("Unknown state space");
     77   case PTXStateSpace::Global:    return "global";
     78   case PTXStateSpace::Constant:  return "const";
     79   case PTXStateSpace::Local:     return "local";
     80   case PTXStateSpace::Parameter: return "param";
     81   case PTXStateSpace::Shared:    return "shared";
     82   }
     83   return NULL;
     84 }
     85 
     86 static const char *getTypeName(Type* type) {
     87   while (true) {
     88     switch (type->getTypeID()) {
     89       default: llvm_unreachable("Unknown type");
     90       case Type::FloatTyID: return ".f32";
     91       case Type::DoubleTyID: return ".f64";
     92       case Type::IntegerTyID:
     93         switch (type->getPrimitiveSizeInBits()) {
     94           default: llvm_unreachable("Unknown integer bit-width");
     95           case 16: return ".u16";
     96           case 32: return ".u32";
     97           case 64: return ".u64";
     98         }
     99       case Type::ArrayTyID:
    100       case Type::PointerTyID:
    101         type = dyn_cast<SequentialType>(type)->getElementType();
    102         break;
    103     }
    104   }
    105   return NULL;
    106 }
    107 
    108 bool PTXAsmPrinter::doFinalization(Module &M) {
    109   // XXX Temproarily remove global variables so that doFinalization() will not
    110   // emit them again (global variables are emitted at beginning).
    111 
    112   Module::GlobalListType &global_list = M.getGlobalList();
    113   int i, n = global_list.size();
    114   GlobalVariable **gv_array = new GlobalVariable* [n];
    115 
    116   // first, back-up GlobalVariable in gv_array
    117   i = 0;
    118   for (Module::global_iterator I = global_list.begin(), E = global_list.end();
    119        I != E; ++I)
    120     gv_array[i++] = &*I;
    121 
    122   // second, empty global_list
    123   while (!global_list.empty())
    124     global_list.remove(global_list.begin());
    125 
    126   // call doFinalization
    127   bool ret = AsmPrinter::doFinalization(M);
    128 
    129   // now we restore global variables
    130   for (i = 0; i < n; i ++)
    131     global_list.insert(global_list.end(), gv_array[i]);
    132 
    133   delete[] gv_array;
    134   return ret;
    135 }
    136 
    137 void PTXAsmPrinter::EmitStartOfAsmFile(Module &M)
    138 {
    139   const PTXSubtarget& ST = TM.getSubtarget<PTXSubtarget>();
    140 
    141   // Emit the PTX .version and .target attributes
    142   OutStreamer.EmitRawText(Twine("\t.version " + ST.getPTXVersionString()));
    143   OutStreamer.EmitRawText(Twine("\t.target " + ST.getTargetString() +
    144                                 (ST.supportsDouble() ? ""
    145                                                      : ", map_f64_to_f32")));
    146   // .address_size directive is optional, but it must immediately follow
    147   // the .target directive if present within a module
    148   if (ST.supportsPTX23()) {
    149     std::string addrSize = ST.is64Bit() ? "64" : "32";
    150     OutStreamer.EmitRawText(Twine("\t.address_size " + addrSize));
    151   }
    152 
    153   OutStreamer.AddBlankLine();
    154 
    155   // Define any .file directives
    156   DebugInfoFinder DbgFinder;
    157   DbgFinder.processModule(M);
    158 
    159   for (DebugInfoFinder::iterator I = DbgFinder.compile_unit_begin(),
    160        E = DbgFinder.compile_unit_end(); I != E; ++I) {
    161     DICompileUnit DIUnit(*I);
    162     StringRef FN = DIUnit.getFilename();
    163     StringRef Dir = DIUnit.getDirectory();
    164     GetOrCreateSourceID(FN, Dir);
    165   }
    166 
    167   OutStreamer.AddBlankLine();
    168 
    169   // declare global variables
    170   for (Module::const_global_iterator i = M.global_begin(), e = M.global_end();
    171        i != e; ++i)
    172     EmitVariableDeclaration(i);
    173 }
    174 
    175 void PTXAsmPrinter::EmitFunctionBodyStart() {
    176   OutStreamer.EmitRawText(Twine("{"));
    177 
    178   const PTXMachineFunctionInfo *MFI = MF->getInfo<PTXMachineFunctionInfo>();
    179   const PTXParamManager &PM = MFI->getParamManager();
    180 
    181   // Print register definitions
    182   std::string regDefs;
    183   unsigned numRegs;
    184 
    185   // pred
    186   numRegs = MFI->getNumRegistersForClass(PTX::RegPredRegisterClass);
    187   if(numRegs > 0) {
    188     regDefs += "\t.reg .pred %p<";
    189     regDefs += utostr(numRegs);
    190     regDefs += ">;\n";
    191   }
    192 
    193   // i16
    194   numRegs = MFI->getNumRegistersForClass(PTX::RegI16RegisterClass);
    195   if(numRegs > 0) {
    196     regDefs += "\t.reg .b16 %rh<";
    197     regDefs += utostr(numRegs);
    198     regDefs += ">;\n";
    199   }
    200 
    201   // i32
    202   numRegs = MFI->getNumRegistersForClass(PTX::RegI32RegisterClass);
    203   if(numRegs > 0) {
    204     regDefs += "\t.reg .b32 %r<";
    205     regDefs += utostr(numRegs);
    206     regDefs += ">;\n";
    207   }
    208 
    209   // i64
    210   numRegs = MFI->getNumRegistersForClass(PTX::RegI64RegisterClass);
    211   if(numRegs > 0) {
    212     regDefs += "\t.reg .b64 %rd<";
    213     regDefs += utostr(numRegs);
    214     regDefs += ">;\n";
    215   }
    216 
    217   // f32
    218   numRegs = MFI->getNumRegistersForClass(PTX::RegF32RegisterClass);
    219   if(numRegs > 0) {
    220     regDefs += "\t.reg .f32 %f<";
    221     regDefs += utostr(numRegs);
    222     regDefs += ">;\n";
    223   }
    224 
    225   // f64
    226   numRegs = MFI->getNumRegistersForClass(PTX::RegF64RegisterClass);
    227   if(numRegs > 0) {
    228     regDefs += "\t.reg .f64 %fd<";
    229     regDefs += utostr(numRegs);
    230     regDefs += ">;\n";
    231   }
    232 
    233   // Local params
    234   for (PTXParamManager::param_iterator i = PM.local_begin(), e = PM.local_end();
    235        i != e; ++i) {
    236     regDefs += "\t.param .b";
    237     regDefs += utostr(PM.getParamSize(*i));
    238     regDefs += " ";
    239     regDefs += PM.getParamName(*i);
    240     regDefs += ";\n";
    241   }
    242 
    243   OutStreamer.EmitRawText(Twine(regDefs));
    244 
    245 
    246   const MachineFrameInfo* FrameInfo = MF->getFrameInfo();
    247   DEBUG(dbgs() << "Have " << FrameInfo->getNumObjects()
    248                << " frame object(s)\n");
    249   for (unsigned i = 0, e = FrameInfo->getNumObjects(); i != e; ++i) {
    250     DEBUG(dbgs() << "Size of object: " << FrameInfo->getObjectSize(i) << "\n");
    251     if (FrameInfo->getObjectSize(i) > 0) {
    252       std::string def = "\t.local .align ";
    253       def += utostr(FrameInfo->getObjectAlignment(i));
    254       def += " .b8";
    255       def += " __local";
    256       def += utostr(i);
    257       def += "[";
    258       def += utostr(FrameInfo->getObjectSize(i)); // Convert to bits
    259       def += "]";
    260       def += ";";
    261       OutStreamer.EmitRawText(Twine(def));
    262     }
    263   }
    264 
    265   //unsigned Index = 1;
    266   // Print parameter passing params
    267   //for (PTXMachineFunctionInfo::param_iterator
    268   //     i = MFI->paramBegin(), e = MFI->paramEnd(); i != e; ++i) {
    269   //  std::string def = "\t.param .b";
    270   //  def += utostr(*i);
    271   //  def += " __ret_";
    272   //  def += utostr(Index);
    273   //  Index++;
    274   //  def += ";";
    275   //  OutStreamer.EmitRawText(Twine(def));
    276   //}
    277 }
    278 
    279 void PTXAsmPrinter::EmitFunctionBodyEnd() {
    280   OutStreamer.EmitRawText(Twine("}"));
    281 }
    282 
    283 void PTXAsmPrinter::EmitInstruction(const MachineInstr *MI) {
    284   MCInst TmpInst;
    285   LowerPTXMachineInstrToMCInst(MI, TmpInst, *this);
    286   OutStreamer.EmitInstruction(TmpInst);
    287 }
    288 
    289 void PTXAsmPrinter::EmitVariableDeclaration(const GlobalVariable *gv) {
    290   // Check to see if this is a special global used by LLVM, if so, emit it.
    291   if (EmitSpecialLLVMGlobal(gv))
    292     return;
    293 
    294   MCSymbol *gvsym = Mang->getSymbol(gv);
    295 
    296   assert(gvsym->isUndefined() && "Cannot define a symbol twice!");
    297 
    298   std::string decl;
    299 
    300   // check if it is defined in some other translation unit
    301   if (gv->isDeclaration())
    302     decl += ".extern ";
    303 
    304   // state space: e.g., .global
    305   decl += ".";
    306   decl += getStateSpaceName(gv->getType()->getAddressSpace());
    307   decl += " ";
    308 
    309   // alignment (optional)
    310   unsigned alignment = gv->getAlignment();
    311   if (alignment != 0) {
    312     decl += ".align ";
    313     decl += utostr(gv->getAlignment());
    314     decl += " ";
    315   }
    316 
    317 
    318   if (PointerType::classof(gv->getType())) {
    319     PointerType* pointerTy = dyn_cast<PointerType>(gv->getType());
    320     Type* elementTy = pointerTy->getElementType();
    321 
    322     decl += ".b8 ";
    323     decl += gvsym->getName();
    324     decl += "[";
    325 
    326     if (elementTy->isArrayTy())
    327     {
    328       assert(elementTy->isArrayTy() && "Only pointers to arrays are supported");
    329 
    330       ArrayType* arrayTy = dyn_cast<ArrayType>(elementTy);
    331       elementTy = arrayTy->getElementType();
    332 
    333       unsigned numElements = arrayTy->getNumElements();
    334 
    335       while (elementTy->isArrayTy()) {
    336 
    337         arrayTy = dyn_cast<ArrayType>(elementTy);
    338         elementTy = arrayTy->getElementType();
    339 
    340         numElements *= arrayTy->getNumElements();
    341       }
    342 
    343       // FIXME: isPrimitiveType() == false for i16?
    344       assert(elementTy->isSingleValueType() &&
    345               "Non-primitive types are not handled");
    346 
    347       // Compute the size of the array, in bytes.
    348       uint64_t arraySize = (elementTy->getPrimitiveSizeInBits() >> 3)
    349                         * numElements;
    350 
    351       decl += utostr(arraySize);
    352     }
    353 
    354     decl += "]";
    355 
    356     // handle string constants (assume ConstantArray means string)
    357 
    358     if (gv->hasInitializer())
    359     {
    360       const Constant *C = gv->getInitializer();
    361       if (const ConstantArray *CA = dyn_cast<ConstantArray>(C))
    362       {
    363         decl += " = {";
    364 
    365         for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
    366         {
    367           if (i > 0)   decl += ",";
    368 
    369           decl += "0x" +
    370                 utohexstr(cast<ConstantInt>(CA->getOperand(i))->getZExtValue());
    371         }
    372 
    373         decl += "}";
    374       }
    375     }
    376   }
    377   else {
    378     // Note: this is currently the fall-through case and most likely generates
    379     //       incorrect code.
    380     decl += getTypeName(gv->getType());
    381     decl += " ";
    382 
    383     decl += gvsym->getName();
    384 
    385     if (ArrayType::classof(gv->getType()) ||
    386         PointerType::classof(gv->getType()))
    387       decl += "[]";
    388   }
    389 
    390   decl += ";";
    391 
    392   OutStreamer.EmitRawText(Twine(decl));
    393 
    394   OutStreamer.AddBlankLine();
    395 }
    396 
    397 void PTXAsmPrinter::EmitFunctionEntryLabel() {
    398   // The function label could have already been emitted if two symbols end up
    399   // conflicting due to asm renaming.  Detect this and emit an error.
    400   if (!CurrentFnSym->isUndefined()) {
    401     report_fatal_error("'" + Twine(CurrentFnSym->getName()) +
    402                        "' label emitted multiple times to assembly file");
    403     return;
    404   }
    405 
    406   const PTXMachineFunctionInfo *MFI = MF->getInfo<PTXMachineFunctionInfo>();
    407   const PTXParamManager &PM = MFI->getParamManager();
    408   const bool isKernel = MFI->isKernel();
    409   const PTXSubtarget& ST = TM.getSubtarget<PTXSubtarget>();
    410   const MachineRegisterInfo& MRI = MF->getRegInfo();
    411 
    412   std::string decl = isKernel ? ".entry" : ".func";
    413 
    414   if (!isKernel) {
    415     decl += " (";
    416     if (ST.useParamSpaceForDeviceArgs()) {
    417       for (PTXParamManager::param_iterator i = PM.ret_begin(), e = PM.ret_end(),
    418            b = i; i != e; ++i) {
    419         if (i != b) {
    420           decl += ", ";
    421         }
    422 
    423         decl += ".param .b";
    424         decl += utostr(PM.getParamSize(*i));
    425         decl += " ";
    426         decl += PM.getParamName(*i);
    427       }
    428     } else {
    429       for (PTXMachineFunctionInfo::reg_iterator
    430            i = MFI->retreg_begin(), e = MFI->retreg_end(), b = i;
    431            i != e; ++i) {
    432         if (i != b) {
    433           decl += ", ";
    434         }
    435         decl += ".reg .";
    436         decl += getRegisterTypeName(*i, MRI);
    437         decl += " ";
    438         decl += MFI->getRegisterName(*i);
    439       }
    440     }
    441     decl += ")";
    442   }
    443 
    444   // Print function name
    445   decl += " ";
    446   decl += CurrentFnSym->getName().str();
    447 
    448   decl += " (";
    449 
    450   const Function *F = MF->getFunction();
    451 
    452   // Print parameters
    453   if (isKernel || ST.useParamSpaceForDeviceArgs()) {
    454     /*for (PTXParamManager::param_iterator i = PM.arg_begin(), e = PM.arg_end(),
    455          b = i; i != e; ++i) {
    456       if (i != b) {
    457         decl += ", ";
    458       }
    459 
    460       decl += ".param .b";
    461       decl += utostr(PM.getParamSize(*i));
    462       decl += " ";
    463       decl += PM.getParamName(*i);
    464     }*/
    465     int Counter = 1;
    466     for (Function::const_arg_iterator i = F->arg_begin(), e = F->arg_end(),
    467          b = i; i != e; ++i) {
    468       if (i != b)
    469         decl += ", ";
    470       const Type *ArgType = (*i).getType();
    471       decl += ".param .b";
    472       if (ArgType->isPointerTy()) {
    473         if (ST.is64Bit())
    474           decl += "64";
    475         else
    476           decl += "32";
    477       } else {
    478         decl += utostr(ArgType->getPrimitiveSizeInBits());
    479       }
    480       if (ArgType->isPointerTy() && ST.emitPtrAttribute()) {
    481         const PointerType *PtrType = dyn_cast<const PointerType>(ArgType);
    482         decl += " .ptr";
    483         switch (PtrType->getAddressSpace()) {
    484         default:
    485           llvm_unreachable("Unknown address space in argument");
    486         case PTXStateSpace::Global:
    487           decl += " .global";
    488           break;
    489         case PTXStateSpace::Shared:
    490           decl += " .shared";
    491           break;
    492         }
    493       }
    494       decl += " __param_";
    495       decl += utostr(Counter++);
    496     }
    497   } else {
    498     for (PTXMachineFunctionInfo::reg_iterator
    499          i = MFI->argreg_begin(), e = MFI->argreg_end(), b = i;
    500          i != e; ++i) {
    501       if (i != b) {
    502         decl += ", ";
    503       }
    504 
    505       decl += ".reg .";
    506       decl += getRegisterTypeName(*i, MRI);
    507       decl += " ";
    508       decl += MFI->getRegisterName(*i);
    509     }
    510   }
    511   decl += ")";
    512 
    513   OutStreamer.EmitRawText(Twine(decl));
    514 }
    515 
    516 unsigned PTXAsmPrinter::GetOrCreateSourceID(StringRef FileName,
    517                                             StringRef DirName) {
    518   // If FE did not provide a file name, then assume stdin.
    519   if (FileName.empty())
    520     return GetOrCreateSourceID("<stdin>", StringRef());
    521 
    522   // MCStream expects full path name as filename.
    523   if (!DirName.empty() && !sys::path::is_absolute(FileName)) {
    524     SmallString<128> FullPathName = DirName;
    525     sys::path::append(FullPathName, FileName);
    526     // Here FullPathName will be copied into StringMap by GetOrCreateSourceID.
    527     return GetOrCreateSourceID(StringRef(FullPathName), StringRef());
    528   }
    529 
    530   StringMapEntry<unsigned> &Entry = SourceIdMap.GetOrCreateValue(FileName);
    531   if (Entry.getValue())
    532     return Entry.getValue();
    533 
    534   unsigned SrcId = SourceIdMap.size();
    535   Entry.setValue(SrcId);
    536 
    537   // Print out a .file directive to specify files for .loc directives.
    538   OutStreamer.EmitDwarfFileDirective(SrcId, Entry.getKey());
    539 
    540   return SrcId;
    541 }
    542 
    543 MCOperand PTXAsmPrinter::GetSymbolRef(const MachineOperand &MO,
    544                                       const MCSymbol *Symbol) {
    545   const MCExpr *Expr;
    546   Expr = MCSymbolRefExpr::Create(Symbol, MCSymbolRefExpr::VK_None, OutContext);
    547   return MCOperand::CreateExpr(Expr);
    548 }
    549 
    550 MCOperand PTXAsmPrinter::lowerOperand(const MachineOperand &MO) {
    551   MCOperand MCOp;
    552   const PTXMachineFunctionInfo *MFI = MF->getInfo<PTXMachineFunctionInfo>();
    553   const MCExpr *Expr;
    554   const char *RegSymbolName;
    555   switch (MO.getType()) {
    556   default:
    557     llvm_unreachable("Unknown operand type");
    558   case MachineOperand::MO_Register:
    559     // We create register operands as symbols, since the PTXInstPrinter class
    560     // has no way to map virtual registers back to a name without some ugly
    561     // hacks.
    562     // FIXME: Figure out a better way to handle virtual register naming.
    563     RegSymbolName = MFI->getRegisterName(MO.getReg());
    564     Expr = MCSymbolRefExpr::Create(RegSymbolName, MCSymbolRefExpr::VK_None,
    565                                    OutContext);
    566     MCOp = MCOperand::CreateExpr(Expr);
    567     break;
    568   case MachineOperand::MO_Immediate:
    569     MCOp = MCOperand::CreateImm(MO.getImm());
    570     break;
    571   case MachineOperand::MO_MachineBasicBlock:
    572     MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
    573                                  MO.getMBB()->getSymbol(), OutContext));
    574     break;
    575   case MachineOperand::MO_GlobalAddress:
    576     MCOp = GetSymbolRef(MO, Mang->getSymbol(MO.getGlobal()));
    577     break;
    578   case MachineOperand::MO_ExternalSymbol:
    579     MCOp = GetSymbolRef(MO, GetExternalSymbolSymbol(MO.getSymbolName()));
    580     break;
    581   case MachineOperand::MO_FPImmediate:
    582     APFloat Val = MO.getFPImm()->getValueAPF();
    583     bool ignored;
    584     Val.convert(APFloat::IEEEdouble, APFloat::rmTowardZero, &ignored);
    585     MCOp = MCOperand::CreateFPImm(Val.convertToDouble());
    586     break;
    587   }
    588 
    589   return MCOp;
    590 }
    591 
    592 // Force static initialization.
    593 extern "C" void LLVMInitializePTXAsmPrinter() {
    594   RegisterAsmPrinter<PTXAsmPrinter> X(ThePTX32Target);
    595   RegisterAsmPrinter<PTXAsmPrinter> Y(ThePTX64Target);
    596 }
    597 
    598