1 //===-- MSP430ISelDAGToDAG.cpp - A dag to dag inst selector for MSP430 ----===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file defines an instruction selector for the MSP430 target. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "MSP430.h" 14 #include "MSP430TargetMachine.h" 15 #include "llvm/CodeGen/MachineFrameInfo.h" 16 #include "llvm/CodeGen/MachineFunction.h" 17 #include "llvm/CodeGen/MachineInstrBuilder.h" 18 #include "llvm/CodeGen/MachineRegisterInfo.h" 19 #include "llvm/CodeGen/SelectionDAG.h" 20 #include "llvm/CodeGen/SelectionDAGISel.h" 21 #include "llvm/CodeGen/TargetLowering.h" 22 #include "llvm/Config/llvm-config.h" 23 #include "llvm/IR/CallingConv.h" 24 #include "llvm/IR/Constants.h" 25 #include "llvm/IR/DerivedTypes.h" 26 #include "llvm/IR/Function.h" 27 #include "llvm/IR/Intrinsics.h" 28 #include "llvm/Support/Debug.h" 29 #include "llvm/Support/ErrorHandling.h" 30 #include "llvm/Support/raw_ostream.h" 31 using namespace llvm; 32 33 #define DEBUG_TYPE "msp430-isel" 34 35 namespace { 36 struct MSP430ISelAddressMode { 37 enum { 38 RegBase, 39 FrameIndexBase 40 } BaseType = RegBase; 41 42 struct { // This is really a union, discriminated by BaseType! 43 SDValue Reg; 44 int FrameIndex = 0; 45 } Base; 46 47 int16_t Disp = 0; 48 const GlobalValue *GV = nullptr; 49 const Constant *CP = nullptr; 50 const BlockAddress *BlockAddr = nullptr; 51 const char *ES = nullptr; 52 int JT = -1; 53 Align Alignment; // CP alignment. 54 55 MSP430ISelAddressMode() = default; 56 57 bool hasSymbolicDisplacement() const { 58 return GV != nullptr || CP != nullptr || ES != nullptr || JT != -1; 59 } 60 61 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 62 LLVM_DUMP_METHOD void dump() { 63 errs() << "MSP430ISelAddressMode " << this << '\n'; 64 if (BaseType == RegBase && Base.Reg.getNode() != nullptr) { 65 errs() << "Base.Reg "; 66 Base.Reg.getNode()->dump(); 67 } else if (BaseType == FrameIndexBase) { 68 errs() << " Base.FrameIndex " << Base.FrameIndex << '\n'; 69 } 70 errs() << " Disp " << Disp << '\n'; 71 if (GV) { 72 errs() << "GV "; 73 GV->dump(); 74 } else if (CP) { 75 errs() << " CP "; 76 CP->dump(); 77 errs() << " Align" << Alignment.value() << '\n'; 78 } else if (ES) { 79 errs() << "ES "; 80 errs() << ES << '\n'; 81 } else if (JT != -1) 82 errs() << " JT" << JT << " Align" << Alignment.value() << '\n'; 83 } 84 #endif 85 }; 86 } 87 88 /// MSP430DAGToDAGISel - MSP430 specific code to select MSP430 machine 89 /// instructions for SelectionDAG operations. 90 /// 91 namespace { 92 class MSP430DAGToDAGISel : public SelectionDAGISel { 93 public: 94 MSP430DAGToDAGISel(MSP430TargetMachine &TM, CodeGenOpt::Level OptLevel) 95 : SelectionDAGISel(TM, OptLevel) {} 96 97 private: 98 StringRef getPassName() const override { 99 return "MSP430 DAG->DAG Pattern Instruction Selection"; 100 } 101 102 bool MatchAddress(SDValue N, MSP430ISelAddressMode &AM); 103 bool MatchWrapper(SDValue N, MSP430ISelAddressMode &AM); 104 bool MatchAddressBase(SDValue N, MSP430ISelAddressMode &AM); 105 106 bool SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID, 107 std::vector<SDValue> &OutOps) override; 108 109 // Include the pieces autogenerated from the target description. 110 #include "MSP430GenDAGISel.inc" 111 112 // Main method to transform nodes into machine nodes. 113 void Select(SDNode *N) override; 114 115 bool tryIndexedLoad(SDNode *Op); 116 bool tryIndexedBinOp(SDNode *Op, SDValue N1, SDValue N2, unsigned Opc8, 117 unsigned Opc16); 118 119 bool SelectAddr(SDValue Addr, SDValue &Base, SDValue &Disp); 120 }; 121 } // end anonymous namespace 122 123 /// createMSP430ISelDag - This pass converts a legalized DAG into a 124 /// MSP430-specific DAG, ready for instruction scheduling. 125 /// 126 FunctionPass *llvm::createMSP430ISelDag(MSP430TargetMachine &TM, 127 CodeGenOpt::Level OptLevel) { 128 return new MSP430DAGToDAGISel(TM, OptLevel); 129 } 130 131 132 /// MatchWrapper - Try to match MSP430ISD::Wrapper node into an addressing mode. 133 /// These wrap things that will resolve down into a symbol reference. If no 134 /// match is possible, this returns true, otherwise it returns false. 135 bool MSP430DAGToDAGISel::MatchWrapper(SDValue N, MSP430ISelAddressMode &AM) { 136 // If the addressing mode already has a symbol as the displacement, we can 137 // never match another symbol. 138 if (AM.hasSymbolicDisplacement()) 139 return true; 140 141 SDValue N0 = N.getOperand(0); 142 143 if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) { 144 AM.GV = G->getGlobal(); 145 AM.Disp += G->getOffset(); 146 //AM.SymbolFlags = G->getTargetFlags(); 147 } else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(N0)) { 148 AM.CP = CP->getConstVal(); 149 AM.Alignment = CP->getAlign(); 150 AM.Disp += CP->getOffset(); 151 //AM.SymbolFlags = CP->getTargetFlags(); 152 } else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(N0)) { 153 AM.ES = S->getSymbol(); 154 //AM.SymbolFlags = S->getTargetFlags(); 155 } else if (JumpTableSDNode *J = dyn_cast<JumpTableSDNode>(N0)) { 156 AM.JT = J->getIndex(); 157 //AM.SymbolFlags = J->getTargetFlags(); 158 } else { 159 AM.BlockAddr = cast<BlockAddressSDNode>(N0)->getBlockAddress(); 160 //AM.SymbolFlags = cast<BlockAddressSDNode>(N0)->getTargetFlags(); 161 } 162 return false; 163 } 164 165 /// MatchAddressBase - Helper for MatchAddress. Add the specified node to the 166 /// specified addressing mode without any further recursion. 167 bool MSP430DAGToDAGISel::MatchAddressBase(SDValue N, MSP430ISelAddressMode &AM) { 168 // Is the base register already occupied? 169 if (AM.BaseType != MSP430ISelAddressMode::RegBase || AM.Base.Reg.getNode()) { 170 // If so, we cannot select it. 171 return true; 172 } 173 174 // Default, generate it as a register. 175 AM.BaseType = MSP430ISelAddressMode::RegBase; 176 AM.Base.Reg = N; 177 return false; 178 } 179 180 bool MSP430DAGToDAGISel::MatchAddress(SDValue N, MSP430ISelAddressMode &AM) { 181 LLVM_DEBUG(errs() << "MatchAddress: "; AM.dump()); 182 183 switch (N.getOpcode()) { 184 default: break; 185 case ISD::Constant: { 186 uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue(); 187 AM.Disp += Val; 188 return false; 189 } 190 191 case MSP430ISD::Wrapper: 192 if (!MatchWrapper(N, AM)) 193 return false; 194 break; 195 196 case ISD::FrameIndex: 197 if (AM.BaseType == MSP430ISelAddressMode::RegBase 198 && AM.Base.Reg.getNode() == nullptr) { 199 AM.BaseType = MSP430ISelAddressMode::FrameIndexBase; 200 AM.Base.FrameIndex = cast<FrameIndexSDNode>(N)->getIndex(); 201 return false; 202 } 203 break; 204 205 case ISD::ADD: { 206 MSP430ISelAddressMode Backup = AM; 207 if (!MatchAddress(N.getNode()->getOperand(0), AM) && 208 !MatchAddress(N.getNode()->getOperand(1), AM)) 209 return false; 210 AM = Backup; 211 if (!MatchAddress(N.getNode()->getOperand(1), AM) && 212 !MatchAddress(N.getNode()->getOperand(0), AM)) 213 return false; 214 AM = Backup; 215 216 break; 217 } 218 219 case ISD::OR: 220 // Handle "X | C" as "X + C" iff X is known to have C bits clear. 221 if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N.getOperand(1))) { 222 MSP430ISelAddressMode Backup = AM; 223 uint64_t Offset = CN->getSExtValue(); 224 // Start with the LHS as an addr mode. 225 if (!MatchAddress(N.getOperand(0), AM) && 226 // Address could not have picked a GV address for the displacement. 227 AM.GV == nullptr && 228 // Check to see if the LHS & C is zero. 229 CurDAG->MaskedValueIsZero(N.getOperand(0), CN->getAPIntValue())) { 230 AM.Disp += Offset; 231 return false; 232 } 233 AM = Backup; 234 } 235 break; 236 } 237 238 return MatchAddressBase(N, AM); 239 } 240 241 /// SelectAddr - returns true if it is able pattern match an addressing mode. 242 /// It returns the operands which make up the maximal addressing mode it can 243 /// match by reference. 244 bool MSP430DAGToDAGISel::SelectAddr(SDValue N, 245 SDValue &Base, SDValue &Disp) { 246 MSP430ISelAddressMode AM; 247 248 if (MatchAddress(N, AM)) 249 return false; 250 251 if (AM.BaseType == MSP430ISelAddressMode::RegBase) 252 if (!AM.Base.Reg.getNode()) 253 AM.Base.Reg = CurDAG->getRegister(MSP430::SR, MVT::i16); 254 255 Base = (AM.BaseType == MSP430ISelAddressMode::FrameIndexBase) 256 ? CurDAG->getTargetFrameIndex( 257 AM.Base.FrameIndex, 258 getTargetLowering()->getPointerTy(CurDAG->getDataLayout())) 259 : AM.Base.Reg; 260 261 if (AM.GV) 262 Disp = CurDAG->getTargetGlobalAddress(AM.GV, SDLoc(N), 263 MVT::i16, AM.Disp, 264 0/*AM.SymbolFlags*/); 265 else if (AM.CP) 266 Disp = CurDAG->getTargetConstantPool(AM.CP, MVT::i16, AM.Alignment, AM.Disp, 267 0 /*AM.SymbolFlags*/); 268 else if (AM.ES) 269 Disp = CurDAG->getTargetExternalSymbol(AM.ES, MVT::i16, 0/*AM.SymbolFlags*/); 270 else if (AM.JT != -1) 271 Disp = CurDAG->getTargetJumpTable(AM.JT, MVT::i16, 0/*AM.SymbolFlags*/); 272 else if (AM.BlockAddr) 273 Disp = CurDAG->getTargetBlockAddress(AM.BlockAddr, MVT::i32, 0, 274 0/*AM.SymbolFlags*/); 275 else 276 Disp = CurDAG->getTargetConstant(AM.Disp, SDLoc(N), MVT::i16); 277 278 return true; 279 } 280 281 bool MSP430DAGToDAGISel:: 282 SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID, 283 std::vector<SDValue> &OutOps) { 284 SDValue Op0, Op1; 285 switch (ConstraintID) { 286 default: return true; 287 case InlineAsm::Constraint_m: // memory 288 if (!SelectAddr(Op, Op0, Op1)) 289 return true; 290 break; 291 } 292 293 OutOps.push_back(Op0); 294 OutOps.push_back(Op1); 295 return false; 296 } 297 298 static bool isValidIndexedLoad(const LoadSDNode *LD) { 299 ISD::MemIndexedMode AM = LD->getAddressingMode(); 300 if (AM != ISD::POST_INC || LD->getExtensionType() != ISD::NON_EXTLOAD) 301 return false; 302 303 EVT VT = LD->getMemoryVT(); 304 305 switch (VT.getSimpleVT().SimpleTy) { 306 case MVT::i8: 307 // Sanity check 308 if (cast<ConstantSDNode>(LD->getOffset())->getZExtValue() != 1) 309 return false; 310 311 break; 312 case MVT::i16: 313 // Sanity check 314 if (cast<ConstantSDNode>(LD->getOffset())->getZExtValue() != 2) 315 return false; 316 317 break; 318 default: 319 return false; 320 } 321 322 return true; 323 } 324 325 bool MSP430DAGToDAGISel::tryIndexedLoad(SDNode *N) { 326 LoadSDNode *LD = cast<LoadSDNode>(N); 327 if (!isValidIndexedLoad(LD)) 328 return false; 329 330 MVT VT = LD->getMemoryVT().getSimpleVT(); 331 332 unsigned Opcode = 0; 333 switch (VT.SimpleTy) { 334 case MVT::i8: 335 Opcode = MSP430::MOV8rp; 336 break; 337 case MVT::i16: 338 Opcode = MSP430::MOV16rp; 339 break; 340 default: 341 return false; 342 } 343 344 ReplaceNode(N, 345 CurDAG->getMachineNode(Opcode, SDLoc(N), VT, MVT::i16, MVT::Other, 346 LD->getBasePtr(), LD->getChain())); 347 return true; 348 } 349 350 bool MSP430DAGToDAGISel::tryIndexedBinOp(SDNode *Op, SDValue N1, SDValue N2, 351 unsigned Opc8, unsigned Opc16) { 352 if (N1.getOpcode() == ISD::LOAD && 353 N1.hasOneUse() && 354 IsLegalToFold(N1, Op, Op, OptLevel)) { 355 LoadSDNode *LD = cast<LoadSDNode>(N1); 356 if (!isValidIndexedLoad(LD)) 357 return false; 358 359 MVT VT = LD->getMemoryVT().getSimpleVT(); 360 unsigned Opc = (VT == MVT::i16 ? Opc16 : Opc8); 361 MachineMemOperand *MemRef = cast<MemSDNode>(N1)->getMemOperand(); 362 SDValue Ops0[] = { N2, LD->getBasePtr(), LD->getChain() }; 363 SDNode *ResNode = 364 CurDAG->SelectNodeTo(Op, Opc, VT, MVT::i16, MVT::Other, Ops0); 365 CurDAG->setNodeMemRefs(cast<MachineSDNode>(ResNode), {MemRef}); 366 // Transfer chain. 367 ReplaceUses(SDValue(N1.getNode(), 2), SDValue(ResNode, 2)); 368 // Transfer writeback. 369 ReplaceUses(SDValue(N1.getNode(), 1), SDValue(ResNode, 1)); 370 return true; 371 } 372 373 return false; 374 } 375 376 377 void MSP430DAGToDAGISel::Select(SDNode *Node) { 378 SDLoc dl(Node); 379 380 // If we have a custom node, we already have selected! 381 if (Node->isMachineOpcode()) { 382 LLVM_DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n"); 383 Node->setNodeId(-1); 384 return; 385 } 386 387 // Few custom selection stuff. 388 switch (Node->getOpcode()) { 389 default: break; 390 case ISD::FrameIndex: { 391 assert(Node->getValueType(0) == MVT::i16); 392 int FI = cast<FrameIndexSDNode>(Node)->getIndex(); 393 SDValue TFI = CurDAG->getTargetFrameIndex(FI, MVT::i16); 394 if (Node->hasOneUse()) { 395 CurDAG->SelectNodeTo(Node, MSP430::ADDframe, MVT::i16, TFI, 396 CurDAG->getTargetConstant(0, dl, MVT::i16)); 397 return; 398 } 399 ReplaceNode(Node, CurDAG->getMachineNode( 400 MSP430::ADDframe, dl, MVT::i16, TFI, 401 CurDAG->getTargetConstant(0, dl, MVT::i16))); 402 return; 403 } 404 case ISD::LOAD: 405 if (tryIndexedLoad(Node)) 406 return; 407 // Other cases are autogenerated. 408 break; 409 case ISD::ADD: 410 if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1), 411 MSP430::ADD8rp, MSP430::ADD16rp)) 412 return; 413 else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0), 414 MSP430::ADD8rp, MSP430::ADD16rp)) 415 return; 416 417 // Other cases are autogenerated. 418 break; 419 case ISD::SUB: 420 if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1), 421 MSP430::SUB8rp, MSP430::SUB16rp)) 422 return; 423 424 // Other cases are autogenerated. 425 break; 426 case ISD::AND: 427 if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1), 428 MSP430::AND8rp, MSP430::AND16rp)) 429 return; 430 else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0), 431 MSP430::AND8rp, MSP430::AND16rp)) 432 return; 433 434 // Other cases are autogenerated. 435 break; 436 case ISD::OR: 437 if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1), 438 MSP430::BIS8rp, MSP430::BIS16rp)) 439 return; 440 else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0), 441 MSP430::BIS8rp, MSP430::BIS16rp)) 442 return; 443 444 // Other cases are autogenerated. 445 break; 446 case ISD::XOR: 447 if (tryIndexedBinOp(Node, Node->getOperand(0), Node->getOperand(1), 448 MSP430::XOR8rp, MSP430::XOR16rp)) 449 return; 450 else if (tryIndexedBinOp(Node, Node->getOperand(1), Node->getOperand(0), 451 MSP430::XOR8rp, MSP430::XOR16rp)) 452 return; 453 454 // Other cases are autogenerated. 455 break; 456 } 457 458 // Select the default instruction 459 SelectCode(Node); 460 } 461