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      1 //===-- NVPTXAsmPrinter.h - NVPTX 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 NVPTX assembly language.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #ifndef NVPTXASMPRINTER_H
     16 #define NVPTXASMPRINTER_H
     17 
     18 #include "NVPTX.h"
     19 #include "NVPTXSubtarget.h"
     20 #include "NVPTXTargetMachine.h"
     21 #include "llvm/ADT/SmallString.h"
     22 #include "llvm/ADT/StringExtras.h"
     23 #include "llvm/CodeGen/AsmPrinter.h"
     24 #include "llvm/IR/Function.h"
     25 #include "llvm/MC/MCAsmInfo.h"
     26 #include "llvm/MC/MCExpr.h"
     27 #include "llvm/MC/MCSymbol.h"
     28 #include "llvm/Support/CommandLine.h"
     29 #include "llvm/Support/FormattedStream.h"
     30 #include "llvm/Target/Mangler.h"
     31 #include "llvm/Target/TargetMachine.h"
     32 #include <fstream>
     33 
     34 // The ptx syntax and format is very different from that usually seem in a .s
     35 // file,
     36 // therefore we are not able to use the MCAsmStreamer interface here.
     37 //
     38 // We are handcrafting the output method here.
     39 //
     40 // A better approach is to clone the MCAsmStreamer to a MCPTXAsmStreamer
     41 // (subclass of MCStreamer).
     42 
     43 // This is defined in AsmPrinter.cpp.
     44 // Used to process the constant expressions in initializers.
     45 namespace nvptx {
     46 const llvm::MCExpr *
     47 LowerConstant(const llvm::Constant *CV, llvm::AsmPrinter &AP);
     48 }
     49 
     50 namespace llvm {
     51 
     52 class LineReader {
     53 private:
     54   unsigned theCurLine;
     55   std::ifstream fstr;
     56   char buff[512];
     57   std::string theFileName;
     58   SmallVector<unsigned, 32> lineOffset;
     59 public:
     60   LineReader(std::string filename) {
     61     theCurLine = 0;
     62     fstr.open(filename.c_str());
     63     theFileName = filename;
     64   }
     65   std::string fileName() { return theFileName; }
     66   ~LineReader() { fstr.close(); }
     67   std::string readLine(unsigned line);
     68 };
     69 
     70 class LLVM_LIBRARY_VISIBILITY NVPTXAsmPrinter : public AsmPrinter {
     71 
     72   class AggBuffer {
     73     // Used to buffer the emitted string for initializing global
     74     // aggregates.
     75     //
     76     // Normally an aggregate (array, vector or structure) is emitted
     77     // as a u8[]. However, if one element/field of the aggregate
     78     // is a non-NULL address, then the aggregate is emitted as u32[]
     79     // or u64[].
     80     //
     81     // We first layout the aggregate in 'buffer' in bytes, except for
     82     // those symbol addresses. For the i-th symbol address in the
     83     //aggregate, its corresponding 4-byte or 8-byte elements in 'buffer'
     84     // are filled with 0s. symbolPosInBuffer[i-1] records its position
     85     // in 'buffer', and Symbols[i-1] records the Value*.
     86     //
     87     // Once we have this AggBuffer setup, we can choose how to print
     88     // it out.
     89   public:
     90     unsigned size;         // size of the buffer in bytes
     91     unsigned char *buffer; // the buffer
     92     unsigned numSymbols;   // number of symbol addresses
     93     SmallVector<unsigned, 4> symbolPosInBuffer;
     94     SmallVector<const Value *, 4> Symbols;
     95 
     96   private:
     97     unsigned curpos;
     98     raw_ostream &O;
     99     NVPTXAsmPrinter &AP;
    100 
    101   public:
    102     AggBuffer(unsigned _size, raw_ostream &_O, NVPTXAsmPrinter &_AP)
    103         : O(_O), AP(_AP) {
    104       buffer = new unsigned char[_size];
    105       size = _size;
    106       curpos = 0;
    107       numSymbols = 0;
    108     }
    109     ~AggBuffer() { delete[] buffer; }
    110     unsigned addBytes(unsigned char *Ptr, int Num, int Bytes) {
    111       assert((curpos + Num) <= size);
    112       assert((curpos + Bytes) <= size);
    113       for (int i = 0; i < Num; ++i) {
    114         buffer[curpos] = Ptr[i];
    115         curpos++;
    116       }
    117       for (int i = Num; i < Bytes; ++i) {
    118         buffer[curpos] = 0;
    119         curpos++;
    120       }
    121       return curpos;
    122     }
    123     unsigned addZeros(int Num) {
    124       assert((curpos + Num) <= size);
    125       for (int i = 0; i < Num; ++i) {
    126         buffer[curpos] = 0;
    127         curpos++;
    128       }
    129       return curpos;
    130     }
    131     void addSymbol(const Value *GVar) {
    132       symbolPosInBuffer.push_back(curpos);
    133       Symbols.push_back(GVar);
    134       numSymbols++;
    135     }
    136     void print() {
    137       if (numSymbols == 0) {
    138         // print out in bytes
    139         for (unsigned i = 0; i < size; i++) {
    140           if (i)
    141             O << ", ";
    142           O << (unsigned int) buffer[i];
    143         }
    144       } else {
    145         // print out in 4-bytes or 8-bytes
    146         unsigned int pos = 0;
    147         unsigned int nSym = 0;
    148         unsigned int nextSymbolPos = symbolPosInBuffer[nSym];
    149         unsigned int nBytes = 4;
    150         if (AP.nvptxSubtarget.is64Bit())
    151           nBytes = 8;
    152         for (pos = 0; pos < size; pos += nBytes) {
    153           if (pos)
    154             O << ", ";
    155           if (pos == nextSymbolPos) {
    156             const Value *v = Symbols[nSym];
    157             if (const GlobalValue *GVar = dyn_cast<GlobalValue>(v)) {
    158               MCSymbol *Name = AP.Mang->getSymbol(GVar);
    159               O << *Name;
    160             } else if (const ConstantExpr *Cexpr = dyn_cast<ConstantExpr>(v)) {
    161               O << *nvptx::LowerConstant(Cexpr, AP);
    162             } else
    163               llvm_unreachable("symbol type unknown");
    164             nSym++;
    165             if (nSym >= numSymbols)
    166               nextSymbolPos = size + 1;
    167             else
    168               nextSymbolPos = symbolPosInBuffer[nSym];
    169           } else if (nBytes == 4)
    170             O << *(unsigned int *)(buffer + pos);
    171           else
    172             O << *(unsigned long long *)(buffer + pos);
    173         }
    174       }
    175     }
    176   };
    177 
    178   friend class AggBuffer;
    179 
    180   virtual void emitSrcInText(StringRef filename, unsigned line);
    181 
    182 private:
    183   virtual const char *getPassName() const { return "NVPTX Assembly Printer"; }
    184 
    185   const Function *F;
    186   std::string CurrentFnName;
    187 
    188   void EmitFunctionEntryLabel();
    189   void EmitFunctionBodyStart();
    190   void EmitFunctionBodyEnd();
    191 
    192   void EmitInstruction(const MachineInstr *);
    193   void lowerToMCInst(const MachineInstr *MI, MCInst &OutMI);
    194   bool lowerOperand(const MachineOperand &MO, MCOperand &MCOp);
    195   MCOperand GetSymbolRef(const MachineOperand &MO, const MCSymbol *Symbol);
    196   unsigned encodeVirtualRegister(unsigned Reg);
    197 
    198   void EmitAlignment(unsigned NumBits, const GlobalValue *GV = 0) const {}
    199 
    200   void printGlobalVariable(const GlobalVariable *GVar);
    201   void printVecModifiedImmediate(const MachineOperand &MO, const char *Modifier,
    202                                  raw_ostream &O);
    203   void printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O,
    204                        const char *Modifier = 0);
    205   void printImplicitDef(const MachineInstr *MI, raw_ostream &O) const;
    206   // definition autogenerated.
    207   void printInstruction(const MachineInstr *MI, raw_ostream &O);
    208   void printModuleLevelGV(const GlobalVariable *GVar, raw_ostream &O,
    209                           bool = false);
    210   void printParamName(int paramIndex, raw_ostream &O);
    211   void printParamName(Function::const_arg_iterator I, int paramIndex,
    212                       raw_ostream &O);
    213   void emitGlobals(const Module &M);
    214   void emitHeader(Module &M, raw_ostream &O);
    215   void emitKernelFunctionDirectives(const Function &F, raw_ostream &O) const;
    216   void emitVirtualRegister(unsigned int vr, bool isVec, raw_ostream &O);
    217   void emitFunctionExternParamList(const MachineFunction &MF);
    218   void emitFunctionParamList(const Function *, raw_ostream &O);
    219   void emitFunctionParamList(const MachineFunction &MF, raw_ostream &O);
    220   void setAndEmitFunctionVirtualRegisters(const MachineFunction &MF);
    221   void emitFunctionTempData(const MachineFunction &MF, unsigned &FrameSize);
    222   bool isImageType(const Type *Ty);
    223   void printReturnValStr(const Function *, raw_ostream &O);
    224   void printReturnValStr(const MachineFunction &MF, raw_ostream &O);
    225 
    226 protected:
    227   bool doInitialization(Module &M);
    228   bool doFinalization(Module &M);
    229 
    230 private:
    231   std::string CurrentBankselLabelInBasicBlock;
    232 
    233   bool GlobalsEmitted;
    234 
    235   // This is specific per MachineFunction.
    236   const MachineRegisterInfo *MRI;
    237   // The contents are specific for each
    238   // MachineFunction. But the size of the
    239   // array is not.
    240   typedef DenseMap<unsigned, unsigned> VRegMap;
    241   typedef DenseMap<const TargetRegisterClass *, VRegMap> VRegRCMap;
    242   VRegRCMap VRegMapping;
    243   // cache the subtarget here.
    244   const NVPTXSubtarget &nvptxSubtarget;
    245   // Build the map between type name and ID based on module's type
    246   // symbol table.
    247   std::map<const Type *, std::string> TypeNameMap;
    248 
    249   // List of variables demoted to a function scope.
    250   std::map<const Function *, std::vector<const GlobalVariable *> > localDecls;
    251 
    252   // To record filename to ID mapping
    253   std::map<std::string, unsigned> filenameMap;
    254   void recordAndEmitFilenames(Module &);
    255 
    256   void emitPTXGlobalVariable(const GlobalVariable *GVar, raw_ostream &O);
    257   void emitPTXAddressSpace(unsigned int AddressSpace, raw_ostream &O) const;
    258   std::string getPTXFundamentalTypeStr(const Type *Ty, bool = true) const;
    259   void printScalarConstant(const Constant *CPV, raw_ostream &O);
    260   void printFPConstant(const ConstantFP *Fp, raw_ostream &O);
    261   void bufferLEByte(const Constant *CPV, int Bytes, AggBuffer *aggBuffer);
    262   void bufferAggregateConstant(const Constant *CV, AggBuffer *aggBuffer);
    263 
    264   void printOperandProper(const MachineOperand &MO);
    265 
    266   void emitLinkageDirective(const GlobalValue *V, raw_ostream &O);
    267   void emitDeclarations(const Module &, raw_ostream &O);
    268   void emitDeclaration(const Function *, raw_ostream &O);
    269 
    270   static const char *getRegisterName(unsigned RegNo);
    271   void emitDemotedVars(const Function *, raw_ostream &);
    272 
    273   LineReader *reader;
    274   LineReader *getReader(std::string);
    275 public:
    276   NVPTXAsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
    277       : AsmPrinter(TM, Streamer),
    278         nvptxSubtarget(TM.getSubtarget<NVPTXSubtarget>()) {
    279     CurrentBankselLabelInBasicBlock = "";
    280     reader = NULL;
    281   }
    282 
    283   ~NVPTXAsmPrinter() {
    284     if (!reader)
    285       delete reader;
    286   }
    287 
    288   bool ignoreLoc(const MachineInstr &);
    289 
    290   virtual void getVirtualRegisterName(unsigned, bool, raw_ostream &);
    291 
    292   DebugLoc prevDebugLoc;
    293   void emitLineNumberAsDotLoc(const MachineInstr &);
    294 };
    295 } // end of namespace
    296 
    297 #endif
    298