1 //===-- NVPTXAsmPrinter.h - NVPTX LLVM assembly writer ----------*- C++ -*-===// 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 LLVM_LIB_TARGET_NVPTX_NVPTXASMPRINTER_H 16 #define LLVM_LIB_TARGET_NVPTX_NVPTXASMPRINTER_H 17 18 #include "NVPTX.h" 19 #include "NVPTXSubtarget.h" 20 #include "NVPTXTargetMachine.h" 21 #include "llvm/ADT/DenseMap.h" 22 #include "llvm/ADT/SmallVector.h" 23 #include "llvm/ADT/StringRef.h" 24 #include "llvm/CodeGen/AsmPrinter.h" 25 #include "llvm/CodeGen/MachineFunction.h" 26 #include "llvm/CodeGen/MachineLoopInfo.h" 27 #include "llvm/IR/Constants.h" 28 #include "llvm/IR/DebugLoc.h" 29 #include "llvm/IR/DerivedTypes.h" 30 #include "llvm/IR/Function.h" 31 #include "llvm/IR/GlobalValue.h" 32 #include "llvm/IR/Value.h" 33 #include "llvm/MC/MCExpr.h" 34 #include "llvm/MC/MCStreamer.h" 35 #include "llvm/MC/MCSymbol.h" 36 #include "llvm/PassAnalysisSupport.h" 37 #include "llvm/Support/Casting.h" 38 #include "llvm/Support/Compiler.h" 39 #include "llvm/Support/ErrorHandling.h" 40 #include "llvm/Support/raw_ostream.h" 41 #include "llvm/Target/TargetMachine.h" 42 #include <algorithm> 43 #include <cassert> 44 #include <map> 45 #include <memory> 46 #include <string> 47 #include <vector> 48 49 // The ptx syntax and format is very different from that usually seem in a .s 50 // file, 51 // therefore we are not able to use the MCAsmStreamer interface here. 52 // 53 // We are handcrafting the output method here. 54 // 55 // A better approach is to clone the MCAsmStreamer to a MCPTXAsmStreamer 56 // (subclass of MCStreamer). 57 58 namespace llvm { 59 60 class MCOperand; 61 62 class LLVM_LIBRARY_VISIBILITY NVPTXAsmPrinter : public AsmPrinter { 63 64 class AggBuffer { 65 // Used to buffer the emitted string for initializing global 66 // aggregates. 67 // 68 // Normally an aggregate (array, vector or structure) is emitted 69 // as a u8[]. However, if one element/field of the aggregate 70 // is a non-NULL address, then the aggregate is emitted as u32[] 71 // or u64[]. 72 // 73 // We first layout the aggregate in 'buffer' in bytes, except for 74 // those symbol addresses. For the i-th symbol address in the 75 //aggregate, its corresponding 4-byte or 8-byte elements in 'buffer' 76 // are filled with 0s. symbolPosInBuffer[i-1] records its position 77 // in 'buffer', and Symbols[i-1] records the Value*. 78 // 79 // Once we have this AggBuffer setup, we can choose how to print 80 // it out. 81 public: 82 unsigned numSymbols; // number of symbol addresses 83 84 private: 85 const unsigned size; // size of the buffer in bytes 86 std::vector<unsigned char> buffer; // the buffer 87 SmallVector<unsigned, 4> symbolPosInBuffer; 88 SmallVector<const Value *, 4> Symbols; 89 // SymbolsBeforeStripping[i] is the original form of Symbols[i] before 90 // stripping pointer casts, i.e., 91 // Symbols[i] == SymbolsBeforeStripping[i]->stripPointerCasts(). 92 // 93 // We need to keep these values because AggBuffer::print decides whether to 94 // emit a "generic()" cast for Symbols[i] depending on the address space of 95 // SymbolsBeforeStripping[i]. 96 SmallVector<const Value *, 4> SymbolsBeforeStripping; 97 unsigned curpos; 98 raw_ostream &O; 99 NVPTXAsmPrinter &AP; 100 bool EmitGeneric; 101 102 public: 103 AggBuffer(unsigned size, raw_ostream &O, NVPTXAsmPrinter &AP) 104 : size(size), buffer(size), O(O), AP(AP) { 105 curpos = 0; 106 numSymbols = 0; 107 EmitGeneric = AP.EmitGeneric; 108 } 109 110 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 } 123 124 unsigned addZeros(int Num) { 125 assert((curpos + Num) <= size); 126 for (int i = 0; i < Num; ++i) { 127 buffer[curpos] = 0; 128 curpos++; 129 } 130 return curpos; 131 } 132 133 void addSymbol(const Value *GVar, const Value *GVarBeforeStripping) { 134 symbolPosInBuffer.push_back(curpos); 135 Symbols.push_back(GVar); 136 SymbolsBeforeStripping.push_back(GVarBeforeStripping); 137 numSymbols++; 138 } 139 140 void print() { 141 if (numSymbols == 0) { 142 // print out in bytes 143 for (unsigned i = 0; i < size; i++) { 144 if (i) 145 O << ", "; 146 O << (unsigned int) buffer[i]; 147 } 148 } else { 149 // print out in 4-bytes or 8-bytes 150 unsigned int pos = 0; 151 unsigned int nSym = 0; 152 unsigned int nextSymbolPos = symbolPosInBuffer[nSym]; 153 unsigned int nBytes = 4; 154 if (static_cast<const NVPTXTargetMachine &>(AP.TM).is64Bit()) 155 nBytes = 8; 156 for (pos = 0; pos < size; pos += nBytes) { 157 if (pos) 158 O << ", "; 159 if (pos == nextSymbolPos) { 160 const Value *v = Symbols[nSym]; 161 const Value *v0 = SymbolsBeforeStripping[nSym]; 162 if (const GlobalValue *GVar = dyn_cast<GlobalValue>(v)) { 163 MCSymbol *Name = AP.getSymbol(GVar); 164 PointerType *PTy = dyn_cast<PointerType>(v0->getType()); 165 bool IsNonGenericPointer = false; // Is v0 a non-generic pointer? 166 if (PTy && PTy->getAddressSpace() != 0) { 167 IsNonGenericPointer = true; 168 } 169 if (EmitGeneric && !isa<Function>(v) && !IsNonGenericPointer) { 170 O << "generic("; 171 Name->print(O, AP.MAI); 172 O << ")"; 173 } else { 174 Name->print(O, AP.MAI); 175 } 176 } else if (const ConstantExpr *CExpr = dyn_cast<ConstantExpr>(v0)) { 177 const MCExpr *Expr = 178 AP.lowerConstantForGV(cast<Constant>(CExpr), false); 179 AP.printMCExpr(*Expr, O); 180 } else 181 llvm_unreachable("symbol type unknown"); 182 nSym++; 183 if (nSym >= numSymbols) 184 nextSymbolPos = size + 1; 185 else 186 nextSymbolPos = symbolPosInBuffer[nSym]; 187 } else if (nBytes == 4) 188 O << *(unsigned int *)(&buffer[pos]); 189 else 190 O << *(unsigned long long *)(&buffer[pos]); 191 } 192 } 193 } 194 }; 195 196 friend class AggBuffer; 197 198 private: 199 StringRef getPassName() const override { return "NVPTX Assembly Printer"; } 200 201 const Function *F; 202 std::string CurrentFnName; 203 204 void EmitBasicBlockStart(const MachineBasicBlock &MBB) const override; 205 void EmitFunctionEntryLabel() override; 206 void EmitFunctionBodyStart() override; 207 void EmitFunctionBodyEnd() override; 208 void emitImplicitDef(const MachineInstr *MI) const override; 209 210 void EmitInstruction(const MachineInstr *) override; 211 void lowerToMCInst(const MachineInstr *MI, MCInst &OutMI); 212 bool lowerOperand(const MachineOperand &MO, MCOperand &MCOp); 213 MCOperand GetSymbolRef(const MCSymbol *Symbol); 214 unsigned encodeVirtualRegister(unsigned Reg); 215 216 void printVecModifiedImmediate(const MachineOperand &MO, const char *Modifier, 217 raw_ostream &O); 218 void printMemOperand(const MachineInstr *MI, int opNum, raw_ostream &O, 219 const char *Modifier = nullptr); 220 void printModuleLevelGV(const GlobalVariable *GVar, raw_ostream &O, 221 bool = false); 222 void printParamName(Function::const_arg_iterator I, int paramIndex, 223 raw_ostream &O); 224 void emitGlobals(const Module &M); 225 void emitHeader(Module &M, raw_ostream &O, const NVPTXSubtarget &STI); 226 void emitKernelFunctionDirectives(const Function &F, raw_ostream &O) const; 227 void emitVirtualRegister(unsigned int vr, raw_ostream &); 228 void emitFunctionParamList(const Function *, raw_ostream &O); 229 void emitFunctionParamList(const MachineFunction &MF, raw_ostream &O); 230 void setAndEmitFunctionVirtualRegisters(const MachineFunction &MF); 231 void printReturnValStr(const Function *, raw_ostream &O); 232 void printReturnValStr(const MachineFunction &MF, raw_ostream &O); 233 bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo, 234 unsigned AsmVariant, const char *ExtraCode, 235 raw_ostream &) override; 236 void printOperand(const MachineInstr *MI, int opNum, raw_ostream &O, 237 const char *Modifier = nullptr); 238 bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo, 239 unsigned AsmVariant, const char *ExtraCode, 240 raw_ostream &) override; 241 242 const MCExpr *lowerConstantForGV(const Constant *CV, bool ProcessingGeneric); 243 void printMCExpr(const MCExpr &Expr, raw_ostream &OS); 244 245 protected: 246 bool doInitialization(Module &M) override; 247 bool doFinalization(Module &M) override; 248 249 private: 250 bool GlobalsEmitted; 251 252 // This is specific per MachineFunction. 253 const MachineRegisterInfo *MRI; 254 // The contents are specific for each 255 // MachineFunction. But the size of the 256 // array is not. 257 typedef DenseMap<unsigned, unsigned> VRegMap; 258 typedef DenseMap<const TargetRegisterClass *, VRegMap> VRegRCMap; 259 VRegRCMap VRegMapping; 260 261 // Cache the subtarget here. 262 const NVPTXSubtarget *nvptxSubtarget; 263 264 // List of variables demoted to a function scope. 265 std::map<const Function *, std::vector<const GlobalVariable *>> localDecls; 266 267 void emitPTXGlobalVariable(const GlobalVariable *GVar, raw_ostream &O); 268 void emitPTXAddressSpace(unsigned int AddressSpace, raw_ostream &O) const; 269 std::string getPTXFundamentalTypeStr(Type *Ty, bool = true) const; 270 void printScalarConstant(const Constant *CPV, raw_ostream &O); 271 void printFPConstant(const ConstantFP *Fp, raw_ostream &O); 272 void bufferLEByte(const Constant *CPV, int Bytes, AggBuffer *aggBuffer); 273 void bufferAggregateConstant(const Constant *CV, AggBuffer *aggBuffer); 274 275 void emitLinkageDirective(const GlobalValue *V, raw_ostream &O); 276 void emitDeclarations(const Module &, raw_ostream &O); 277 void emitDeclaration(const Function *, raw_ostream &O); 278 void emitDemotedVars(const Function *, raw_ostream &); 279 280 bool lowerImageHandleOperand(const MachineInstr *MI, unsigned OpNo, 281 MCOperand &MCOp); 282 void lowerImageHandleSymbol(unsigned Index, MCOperand &MCOp); 283 284 bool isLoopHeaderOfNoUnroll(const MachineBasicBlock &MBB) const; 285 286 // Used to control the need to emit .generic() in the initializer of 287 // module scope variables. 288 // Although ptx supports the hybrid mode like the following, 289 // .global .u32 a; 290 // .global .u32 b; 291 // .global .u32 addr[] = {a, generic(b)} 292 // we have difficulty representing the difference in the NVVM IR. 293 // 294 // Since the address value should always be generic in CUDA C and always 295 // be specific in OpenCL, we use this simple control here. 296 // 297 bool EmitGeneric; 298 299 public: 300 NVPTXAsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer) 301 : AsmPrinter(TM, std::move(Streamer)), 302 EmitGeneric(static_cast<NVPTXTargetMachine &>(TM).getDrvInterface() == 303 NVPTX::CUDA) {} 304 305 bool runOnMachineFunction(MachineFunction &F) override; 306 307 void getAnalysisUsage(AnalysisUsage &AU) const override { 308 AU.addRequired<MachineLoopInfo>(); 309 AsmPrinter::getAnalysisUsage(AU); 310 } 311 312 std::string getVirtualRegisterName(unsigned) const; 313 314 const MCSymbol *getFunctionFrameSymbol() const override; 315 }; 316 317 } // end namespace llvm 318 319 #endif // LLVM_LIB_TARGET_NVPTX_NVPTXASMPRINTER_H 320
