1 //===---------------------------- StackMaps.cpp ---------------------------===// 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 #define DEBUG_TYPE "stackmaps" 11 12 #include "llvm/CodeGen/StackMaps.h" 13 14 #include "llvm/CodeGen/AsmPrinter.h" 15 #include "llvm/CodeGen/MachineInstr.h" 16 #include "llvm/MC/MCContext.h" 17 #include "llvm/MC/MCExpr.h" 18 #include "llvm/MC/MCObjectFileInfo.h" 19 #include "llvm/MC/MCSectionMachO.h" 20 #include "llvm/MC/MCStreamer.h" 21 #include "llvm/Support/Debug.h" 22 #include "llvm/Support/raw_ostream.h" 23 #include "llvm/Target/TargetOpcodes.h" 24 #include "llvm/Target/TargetMachine.h" 25 #include "llvm/Target/TargetRegisterInfo.h" 26 27 #include <iterator> 28 29 using namespace llvm; 30 31 PatchPointOpers::PatchPointOpers(const MachineInstr *MI): 32 MI(MI), 33 HasDef(MI->getOperand(0).isReg() && MI->getOperand(0).isDef() && 34 !MI->getOperand(0).isImplicit()), 35 IsAnyReg(MI->getOperand(getMetaIdx(CCPos)).getImm() == CallingConv::AnyReg) { 36 37 #ifndef NDEBUG 38 { 39 unsigned CheckStartIdx = 0, e = MI->getNumOperands(); 40 while (CheckStartIdx < e && MI->getOperand(CheckStartIdx).isReg() && 41 MI->getOperand(CheckStartIdx).isDef() && 42 !MI->getOperand(CheckStartIdx).isImplicit()) 43 ++CheckStartIdx; 44 45 assert(getMetaIdx() == CheckStartIdx && 46 "Unexpected additonal definition in Patchpoint intrinsic."); 47 } 48 #endif 49 } 50 51 unsigned PatchPointOpers::getNextScratchIdx(unsigned StartIdx) const { 52 if (!StartIdx) 53 StartIdx = getVarIdx(); 54 55 // Find the next scratch register (implicit def and early clobber) 56 unsigned ScratchIdx = StartIdx, e = MI->getNumOperands(); 57 while (ScratchIdx < e && 58 !(MI->getOperand(ScratchIdx).isReg() && 59 MI->getOperand(ScratchIdx).isDef() && 60 MI->getOperand(ScratchIdx).isImplicit() && 61 MI->getOperand(ScratchIdx).isEarlyClobber())) 62 ++ScratchIdx; 63 64 assert(ScratchIdx != e && "No scratch register available"); 65 return ScratchIdx; 66 } 67 68 void StackMaps::recordStackMapOpers(const MachineInstr &MI, uint32_t ID, 69 MachineInstr::const_mop_iterator MOI, 70 MachineInstr::const_mop_iterator MOE, 71 bool recordResult) { 72 73 MCContext &OutContext = AP.OutStreamer.getContext(); 74 MCSymbol *MILabel = OutContext.CreateTempSymbol(); 75 AP.OutStreamer.EmitLabel(MILabel); 76 77 LocationVec CallsiteLocs; 78 79 if (recordResult) { 80 std::pair<Location, MachineInstr::const_mop_iterator> ParseResult = 81 OpParser(MI.operands_begin(), llvm::next(MI.operands_begin()), AP.TM); 82 83 Location &Loc = ParseResult.first; 84 assert(Loc.LocType == Location::Register && 85 "Stackmap return location must be a register."); 86 CallsiteLocs.push_back(Loc); 87 } 88 89 while (MOI != MOE) { 90 std::pair<Location, MachineInstr::const_mop_iterator> ParseResult = 91 OpParser(MOI, MOE, AP.TM); 92 93 Location &Loc = ParseResult.first; 94 95 // Move large constants into the constant pool. 96 if (Loc.LocType == Location::Constant && (Loc.Offset & ~0xFFFFFFFFULL)) { 97 Loc.LocType = Location::ConstantIndex; 98 Loc.Offset = ConstPool.getConstantIndex(Loc.Offset); 99 } 100 101 CallsiteLocs.push_back(Loc); 102 MOI = ParseResult.second; 103 } 104 105 const MCExpr *CSOffsetExpr = MCBinaryExpr::CreateSub( 106 MCSymbolRefExpr::Create(MILabel, OutContext), 107 MCSymbolRefExpr::Create(AP.CurrentFnSym, OutContext), 108 OutContext); 109 110 CSInfos.push_back(CallsiteInfo(CSOffsetExpr, ID, CallsiteLocs)); 111 } 112 113 static MachineInstr::const_mop_iterator 114 getStackMapEndMOP(MachineInstr::const_mop_iterator MOI, 115 MachineInstr::const_mop_iterator MOE) { 116 for (; MOI != MOE; ++MOI) 117 if (MOI->isRegMask() || (MOI->isReg() && MOI->isImplicit())) 118 break; 119 120 return MOI; 121 } 122 123 void StackMaps::recordStackMap(const MachineInstr &MI) { 124 assert(MI.getOpcode() == TargetOpcode::STACKMAP && "exected stackmap"); 125 126 int64_t ID = MI.getOperand(0).getImm(); 127 assert((int32_t)ID == ID && "Stack maps hold 32-bit IDs"); 128 recordStackMapOpers(MI, ID, llvm::next(MI.operands_begin(), 2), 129 getStackMapEndMOP(MI.operands_begin(), 130 MI.operands_end())); 131 } 132 133 void StackMaps::recordPatchPoint(const MachineInstr &MI) { 134 assert(MI.getOpcode() == TargetOpcode::PATCHPOINT && "exected stackmap"); 135 136 PatchPointOpers opers(&MI); 137 int64_t ID = opers.getMetaOper(PatchPointOpers::IDPos).getImm(); 138 assert((int32_t)ID == ID && "Stack maps hold 32-bit IDs"); 139 MachineInstr::const_mop_iterator MOI = 140 llvm::next(MI.operands_begin(), opers.getStackMapStartIdx()); 141 recordStackMapOpers(MI, ID, MOI, getStackMapEndMOP(MOI, MI.operands_end()), 142 opers.isAnyReg() && opers.hasDef()); 143 144 #ifndef NDEBUG 145 // verify anyregcc 146 LocationVec &Locations = CSInfos.back().Locations; 147 if (opers.isAnyReg()) { 148 unsigned NArgs = opers.getMetaOper(PatchPointOpers::NArgPos).getImm(); 149 for (unsigned i = 0, e = (opers.hasDef() ? NArgs+1 : NArgs); i != e; ++i) 150 assert(Locations[i].LocType == Location::Register && 151 "anyreg arg must be in reg."); 152 } 153 #endif 154 } 155 156 /// serializeToStackMapSection conceptually populates the following fields: 157 /// 158 /// uint32 : Reserved (header) 159 /// uint32 : NumConstants 160 /// int64 : Constants[NumConstants] 161 /// uint32 : NumRecords 162 /// StkMapRecord[NumRecords] { 163 /// uint32 : PatchPoint ID 164 /// uint32 : Instruction Offset 165 /// uint16 : Reserved (record flags) 166 /// uint16 : NumLocations 167 /// Location[NumLocations] { 168 /// uint8 : Register | Direct | Indirect | Constant | ConstantIndex 169 /// uint8 : Size in Bytes 170 /// uint16 : Dwarf RegNum 171 /// int32 : Offset 172 /// } 173 /// } 174 /// 175 /// Location Encoding, Type, Value: 176 /// 0x1, Register, Reg (value in register) 177 /// 0x2, Direct, Reg + Offset (frame index) 178 /// 0x3, Indirect, [Reg + Offset] (spilled value) 179 /// 0x4, Constant, Offset (small constant) 180 /// 0x5, ConstIndex, Constants[Offset] (large constant) 181 /// 182 void StackMaps::serializeToStackMapSection() { 183 // Bail out if there's no stack map data. 184 if (CSInfos.empty()) 185 return; 186 187 MCContext &OutContext = AP.OutStreamer.getContext(); 188 const TargetRegisterInfo *TRI = AP.TM.getRegisterInfo(); 189 190 // Create the section. 191 const MCSection *StackMapSection = 192 OutContext.getObjectFileInfo()->getStackMapSection(); 193 AP.OutStreamer.SwitchSection(StackMapSection); 194 195 // Emit a dummy symbol to force section inclusion. 196 AP.OutStreamer.EmitLabel( 197 OutContext.GetOrCreateSymbol(Twine("__LLVM_StackMaps"))); 198 199 // Serialize data. 200 const char *WSMP = "Stack Maps: "; 201 (void)WSMP; 202 const MCRegisterInfo &MCRI = *OutContext.getRegisterInfo(); 203 204 DEBUG(dbgs() << "********** Stack Map Output **********\n"); 205 206 // Header. 207 AP.OutStreamer.EmitIntValue(0, 4); 208 209 // Num constants. 210 AP.OutStreamer.EmitIntValue(ConstPool.getNumConstants(), 4); 211 212 // Constant pool entries. 213 for (unsigned i = 0; i < ConstPool.getNumConstants(); ++i) 214 AP.OutStreamer.EmitIntValue(ConstPool.getConstant(i), 8); 215 216 DEBUG(dbgs() << WSMP << "#callsites = " << CSInfos.size() << "\n"); 217 AP.OutStreamer.EmitIntValue(CSInfos.size(), 4); 218 219 for (CallsiteInfoList::const_iterator CSII = CSInfos.begin(), 220 CSIE = CSInfos.end(); 221 CSII != CSIE; ++CSII) { 222 223 unsigned CallsiteID = CSII->ID; 224 const LocationVec &CSLocs = CSII->Locations; 225 226 DEBUG(dbgs() << WSMP << "callsite " << CallsiteID << "\n"); 227 228 // Verify stack map entry. It's better to communicate a problem to the 229 // runtime than crash in case of in-process compilation. Currently, we do 230 // simple overflow checks, but we may eventually communicate other 231 // compilation errors this way. 232 if (CSLocs.size() > UINT16_MAX) { 233 AP.OutStreamer.EmitIntValue(UINT32_MAX, 4); // Invalid ID. 234 AP.OutStreamer.EmitValue(CSII->CSOffsetExpr, 4); 235 AP.OutStreamer.EmitIntValue(0, 2); // Reserved. 236 AP.OutStreamer.EmitIntValue(0, 2); // 0 locations. 237 continue; 238 } 239 240 AP.OutStreamer.EmitIntValue(CallsiteID, 4); 241 AP.OutStreamer.EmitValue(CSII->CSOffsetExpr, 4); 242 243 // Reserved for flags. 244 AP.OutStreamer.EmitIntValue(0, 2); 245 246 DEBUG(dbgs() << WSMP << " has " << CSLocs.size() << " locations\n"); 247 248 AP.OutStreamer.EmitIntValue(CSLocs.size(), 2); 249 250 unsigned operIdx = 0; 251 for (LocationVec::const_iterator LocI = CSLocs.begin(), LocE = CSLocs.end(); 252 LocI != LocE; ++LocI, ++operIdx) { 253 const Location &Loc = *LocI; 254 DEBUG( 255 dbgs() << WSMP << " Loc " << operIdx << ": "; 256 switch (Loc.LocType) { 257 case Location::Unprocessed: 258 dbgs() << "<Unprocessed operand>"; 259 break; 260 case Location::Register: 261 dbgs() << "Register " << MCRI.getName(Loc.Reg); 262 break; 263 case Location::Direct: 264 dbgs() << "Direct " << MCRI.getName(Loc.Reg); 265 if (Loc.Offset) 266 dbgs() << " + " << Loc.Offset; 267 break; 268 case Location::Indirect: 269 dbgs() << "Indirect " << MCRI.getName(Loc.Reg) 270 << " + " << Loc.Offset; 271 break; 272 case Location::Constant: 273 dbgs() << "Constant " << Loc.Offset; 274 break; 275 case Location::ConstantIndex: 276 dbgs() << "Constant Index " << Loc.Offset; 277 break; 278 } 279 dbgs() << "\n"; 280 ); 281 282 unsigned RegNo = 0; 283 int Offset = Loc.Offset; 284 if(Loc.Reg) { 285 RegNo = MCRI.getDwarfRegNum(Loc.Reg, false); 286 for (MCSuperRegIterator SR(Loc.Reg, TRI); 287 SR.isValid() && (int)RegNo < 0; ++SR) { 288 RegNo = TRI->getDwarfRegNum(*SR, false); 289 } 290 // If this is a register location, put the subregister byte offset in 291 // the location offset. 292 if (Loc.LocType == Location::Register) { 293 assert(!Loc.Offset && "Register location should have zero offset"); 294 unsigned LLVMRegNo = MCRI.getLLVMRegNum(RegNo, false); 295 unsigned SubRegIdx = MCRI.getSubRegIndex(LLVMRegNo, Loc.Reg); 296 if (SubRegIdx) 297 Offset = MCRI.getSubRegIdxOffset(SubRegIdx); 298 } 299 } 300 else { 301 assert(Loc.LocType != Location::Register && 302 "Missing location register"); 303 } 304 AP.OutStreamer.EmitIntValue(Loc.LocType, 1); 305 AP.OutStreamer.EmitIntValue(Loc.Size, 1); 306 AP.OutStreamer.EmitIntValue(RegNo, 2); 307 AP.OutStreamer.EmitIntValue(Offset, 4); 308 } 309 } 310 311 AP.OutStreamer.AddBlankLine(); 312 313 CSInfos.clear(); 314 } 315