1 //===-- XCoreInstrInfo.cpp - XCore Instruction Information ----------------===// 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 the XCore implementation of the TargetInstrInfo class. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "XCoreInstrInfo.h" 15 #include "XCore.h" 16 #include "XCoreMachineFunctionInfo.h" 17 #include "llvm/ADT/STLExtras.h" 18 #include "llvm/CodeGen/MachineFrameInfo.h" 19 #include "llvm/CodeGen/MachineInstrBuilder.h" 20 #include "llvm/MC/MCContext.h" 21 #include "llvm/Support/Debug.h" 22 #include "llvm/Support/ErrorHandling.h" 23 #include "llvm/Support/TargetRegistry.h" 24 25 #define GET_INSTRINFO_CTOR_DTOR 26 #include "XCoreGenInstrInfo.inc" 27 28 namespace llvm { 29 namespace XCore { 30 31 // XCore Condition Codes 32 enum CondCode { 33 COND_TRUE, 34 COND_FALSE, 35 COND_INVALID 36 }; 37 } 38 } 39 40 using namespace llvm; 41 42 43 // Pin the vtable to this file. 44 void XCoreInstrInfo::anchor() {} 45 46 XCoreInstrInfo::XCoreInstrInfo() 47 : XCoreGenInstrInfo(XCore::ADJCALLSTACKDOWN, XCore::ADJCALLSTACKUP), 48 RI() { 49 } 50 51 static bool isZeroImm(const MachineOperand &op) { 52 return op.isImm() && op.getImm() == 0; 53 } 54 55 /// isLoadFromStackSlot - If the specified machine instruction is a direct 56 /// load from a stack slot, return the virtual or physical register number of 57 /// the destination along with the FrameIndex of the loaded stack slot. If 58 /// not, return 0. This predicate must return 0 if the instruction has 59 /// any side effects other than loading from the stack slot. 60 unsigned 61 XCoreInstrInfo::isLoadFromStackSlot(const MachineInstr *MI, int &FrameIndex) const{ 62 int Opcode = MI->getOpcode(); 63 if (Opcode == XCore::LDWFI) 64 { 65 if ((MI->getOperand(1).isFI()) && // is a stack slot 66 (MI->getOperand(2).isImm()) && // the imm is zero 67 (isZeroImm(MI->getOperand(2)))) 68 { 69 FrameIndex = MI->getOperand(1).getIndex(); 70 return MI->getOperand(0).getReg(); 71 } 72 } 73 return 0; 74 } 75 76 /// isStoreToStackSlot - If the specified machine instruction is a direct 77 /// store to a stack slot, return the virtual or physical register number of 78 /// the source reg along with the FrameIndex of the loaded stack slot. If 79 /// not, return 0. This predicate must return 0 if the instruction has 80 /// any side effects other than storing to the stack slot. 81 unsigned 82 XCoreInstrInfo::isStoreToStackSlot(const MachineInstr *MI, 83 int &FrameIndex) const { 84 int Opcode = MI->getOpcode(); 85 if (Opcode == XCore::STWFI) 86 { 87 if ((MI->getOperand(1).isFI()) && // is a stack slot 88 (MI->getOperand(2).isImm()) && // the imm is zero 89 (isZeroImm(MI->getOperand(2)))) 90 { 91 FrameIndex = MI->getOperand(1).getIndex(); 92 return MI->getOperand(0).getReg(); 93 } 94 } 95 return 0; 96 } 97 98 //===----------------------------------------------------------------------===// 99 // Branch Analysis 100 //===----------------------------------------------------------------------===// 101 102 static inline bool IsBRU(unsigned BrOpc) { 103 return BrOpc == XCore::BRFU_u6 104 || BrOpc == XCore::BRFU_lu6 105 || BrOpc == XCore::BRBU_u6 106 || BrOpc == XCore::BRBU_lu6; 107 } 108 109 static inline bool IsBRT(unsigned BrOpc) { 110 return BrOpc == XCore::BRFT_ru6 111 || BrOpc == XCore::BRFT_lru6 112 || BrOpc == XCore::BRBT_ru6 113 || BrOpc == XCore::BRBT_lru6; 114 } 115 116 static inline bool IsBRF(unsigned BrOpc) { 117 return BrOpc == XCore::BRFF_ru6 118 || BrOpc == XCore::BRFF_lru6 119 || BrOpc == XCore::BRBF_ru6 120 || BrOpc == XCore::BRBF_lru6; 121 } 122 123 static inline bool IsCondBranch(unsigned BrOpc) { 124 return IsBRF(BrOpc) || IsBRT(BrOpc); 125 } 126 127 static inline bool IsBR_JT(unsigned BrOpc) { 128 return BrOpc == XCore::BR_JT 129 || BrOpc == XCore::BR_JT32; 130 } 131 132 /// GetCondFromBranchOpc - Return the XCore CC that matches 133 /// the correspondent Branch instruction opcode. 134 static XCore::CondCode GetCondFromBranchOpc(unsigned BrOpc) 135 { 136 if (IsBRT(BrOpc)) { 137 return XCore::COND_TRUE; 138 } else if (IsBRF(BrOpc)) { 139 return XCore::COND_FALSE; 140 } else { 141 return XCore::COND_INVALID; 142 } 143 } 144 145 /// GetCondBranchFromCond - Return the Branch instruction 146 /// opcode that matches the cc. 147 static inline unsigned GetCondBranchFromCond(XCore::CondCode CC) 148 { 149 switch (CC) { 150 default: llvm_unreachable("Illegal condition code!"); 151 case XCore::COND_TRUE : return XCore::BRFT_lru6; 152 case XCore::COND_FALSE : return XCore::BRFF_lru6; 153 } 154 } 155 156 /// GetOppositeBranchCondition - Return the inverse of the specified 157 /// condition, e.g. turning COND_E to COND_NE. 158 static inline XCore::CondCode GetOppositeBranchCondition(XCore::CondCode CC) 159 { 160 switch (CC) { 161 default: llvm_unreachable("Illegal condition code!"); 162 case XCore::COND_TRUE : return XCore::COND_FALSE; 163 case XCore::COND_FALSE : return XCore::COND_TRUE; 164 } 165 } 166 167 /// AnalyzeBranch - Analyze the branching code at the end of MBB, returning 168 /// true if it cannot be understood (e.g. it's a switch dispatch or isn't 169 /// implemented for a target). Upon success, this returns false and returns 170 /// with the following information in various cases: 171 /// 172 /// 1. If this block ends with no branches (it just falls through to its succ) 173 /// just return false, leaving TBB/FBB null. 174 /// 2. If this block ends with only an unconditional branch, it sets TBB to be 175 /// the destination block. 176 /// 3. If this block ends with an conditional branch and it falls through to 177 /// an successor block, it sets TBB to be the branch destination block and a 178 /// list of operands that evaluate the condition. These 179 /// operands can be passed to other TargetInstrInfo methods to create new 180 /// branches. 181 /// 4. If this block ends with an conditional branch and an unconditional 182 /// block, it returns the 'true' destination in TBB, the 'false' destination 183 /// in FBB, and a list of operands that evaluate the condition. These 184 /// operands can be passed to other TargetInstrInfo methods to create new 185 /// branches. 186 /// 187 /// Note that RemoveBranch and InsertBranch must be implemented to support 188 /// cases where this method returns success. 189 /// 190 bool 191 XCoreInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB, 192 MachineBasicBlock *&FBB, 193 SmallVectorImpl<MachineOperand> &Cond, 194 bool AllowModify) const { 195 // If the block has no terminators, it just falls into the block after it. 196 MachineBasicBlock::iterator I = MBB.end(); 197 if (I == MBB.begin()) 198 return false; 199 --I; 200 while (I->isDebugValue()) { 201 if (I == MBB.begin()) 202 return false; 203 --I; 204 } 205 if (!isUnpredicatedTerminator(I)) 206 return false; 207 208 // Get the last instruction in the block. 209 MachineInstr *LastInst = I; 210 211 // If there is only one terminator instruction, process it. 212 if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) { 213 if (IsBRU(LastInst->getOpcode())) { 214 TBB = LastInst->getOperand(0).getMBB(); 215 return false; 216 } 217 218 XCore::CondCode BranchCode = GetCondFromBranchOpc(LastInst->getOpcode()); 219 if (BranchCode == XCore::COND_INVALID) 220 return true; // Can't handle indirect branch. 221 222 // Conditional branch 223 // Block ends with fall-through condbranch. 224 225 TBB = LastInst->getOperand(1).getMBB(); 226 Cond.push_back(MachineOperand::CreateImm(BranchCode)); 227 Cond.push_back(LastInst->getOperand(0)); 228 return false; 229 } 230 231 // Get the instruction before it if it's a terminator. 232 MachineInstr *SecondLastInst = I; 233 234 // If there are three terminators, we don't know what sort of block this is. 235 if (SecondLastInst && I != MBB.begin() && 236 isUnpredicatedTerminator(--I)) 237 return true; 238 239 unsigned SecondLastOpc = SecondLastInst->getOpcode(); 240 XCore::CondCode BranchCode = GetCondFromBranchOpc(SecondLastOpc); 241 242 // If the block ends with conditional branch followed by unconditional, 243 // handle it. 244 if (BranchCode != XCore::COND_INVALID 245 && IsBRU(LastInst->getOpcode())) { 246 247 TBB = SecondLastInst->getOperand(1).getMBB(); 248 Cond.push_back(MachineOperand::CreateImm(BranchCode)); 249 Cond.push_back(SecondLastInst->getOperand(0)); 250 251 FBB = LastInst->getOperand(0).getMBB(); 252 return false; 253 } 254 255 // If the block ends with two unconditional branches, handle it. The second 256 // one is not executed, so remove it. 257 if (IsBRU(SecondLastInst->getOpcode()) && 258 IsBRU(LastInst->getOpcode())) { 259 TBB = SecondLastInst->getOperand(0).getMBB(); 260 I = LastInst; 261 if (AllowModify) 262 I->eraseFromParent(); 263 return false; 264 } 265 266 // Likewise if it ends with a branch table followed by an unconditional branch. 267 if (IsBR_JT(SecondLastInst->getOpcode()) && IsBRU(LastInst->getOpcode())) { 268 I = LastInst; 269 if (AllowModify) 270 I->eraseFromParent(); 271 return true; 272 } 273 274 // Otherwise, can't handle this. 275 return true; 276 } 277 278 unsigned 279 XCoreInstrInfo::InsertBranch(MachineBasicBlock &MBB,MachineBasicBlock *TBB, 280 MachineBasicBlock *FBB, 281 const SmallVectorImpl<MachineOperand> &Cond, 282 DebugLoc DL)const{ 283 // Shouldn't be a fall through. 284 assert(TBB && "InsertBranch must not be told to insert a fallthrough"); 285 assert((Cond.size() == 2 || Cond.size() == 0) && 286 "Unexpected number of components!"); 287 288 if (FBB == 0) { // One way branch. 289 if (Cond.empty()) { 290 // Unconditional branch 291 BuildMI(&MBB, DL, get(XCore::BRFU_lu6)).addMBB(TBB); 292 } else { 293 // Conditional branch. 294 unsigned Opc = GetCondBranchFromCond((XCore::CondCode)Cond[0].getImm()); 295 BuildMI(&MBB, DL, get(Opc)).addReg(Cond[1].getReg()) 296 .addMBB(TBB); 297 } 298 return 1; 299 } 300 301 // Two-way Conditional branch. 302 assert(Cond.size() == 2 && "Unexpected number of components!"); 303 unsigned Opc = GetCondBranchFromCond((XCore::CondCode)Cond[0].getImm()); 304 BuildMI(&MBB, DL, get(Opc)).addReg(Cond[1].getReg()) 305 .addMBB(TBB); 306 BuildMI(&MBB, DL, get(XCore::BRFU_lu6)).addMBB(FBB); 307 return 2; 308 } 309 310 unsigned 311 XCoreInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const { 312 MachineBasicBlock::iterator I = MBB.end(); 313 if (I == MBB.begin()) return 0; 314 --I; 315 while (I->isDebugValue()) { 316 if (I == MBB.begin()) 317 return 0; 318 --I; 319 } 320 if (!IsBRU(I->getOpcode()) && !IsCondBranch(I->getOpcode())) 321 return 0; 322 323 // Remove the branch. 324 I->eraseFromParent(); 325 326 I = MBB.end(); 327 328 if (I == MBB.begin()) return 1; 329 --I; 330 if (!IsCondBranch(I->getOpcode())) 331 return 1; 332 333 // Remove the branch. 334 I->eraseFromParent(); 335 return 2; 336 } 337 338 void XCoreInstrInfo::copyPhysReg(MachineBasicBlock &MBB, 339 MachineBasicBlock::iterator I, DebugLoc DL, 340 unsigned DestReg, unsigned SrcReg, 341 bool KillSrc) const { 342 bool GRDest = XCore::GRRegsRegClass.contains(DestReg); 343 bool GRSrc = XCore::GRRegsRegClass.contains(SrcReg); 344 345 if (GRDest && GRSrc) { 346 BuildMI(MBB, I, DL, get(XCore::ADD_2rus), DestReg) 347 .addReg(SrcReg, getKillRegState(KillSrc)) 348 .addImm(0); 349 return; 350 } 351 352 if (GRDest && SrcReg == XCore::SP) { 353 BuildMI(MBB, I, DL, get(XCore::LDAWSP_ru6), DestReg).addImm(0); 354 return; 355 } 356 357 if (DestReg == XCore::SP && GRSrc) { 358 BuildMI(MBB, I, DL, get(XCore::SETSP_1r)) 359 .addReg(SrcReg, getKillRegState(KillSrc)); 360 return; 361 } 362 llvm_unreachable("Impossible reg-to-reg copy"); 363 } 364 365 void XCoreInstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB, 366 MachineBasicBlock::iterator I, 367 unsigned SrcReg, bool isKill, 368 int FrameIndex, 369 const TargetRegisterClass *RC, 370 const TargetRegisterInfo *TRI) const 371 { 372 DebugLoc DL; 373 if (I != MBB.end()) DL = I->getDebugLoc(); 374 BuildMI(MBB, I, DL, get(XCore::STWFI)) 375 .addReg(SrcReg, getKillRegState(isKill)) 376 .addFrameIndex(FrameIndex) 377 .addImm(0); 378 } 379 380 void XCoreInstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB, 381 MachineBasicBlock::iterator I, 382 unsigned DestReg, int FrameIndex, 383 const TargetRegisterClass *RC, 384 const TargetRegisterInfo *TRI) const 385 { 386 DebugLoc DL; 387 if (I != MBB.end()) DL = I->getDebugLoc(); 388 BuildMI(MBB, I, DL, get(XCore::LDWFI), DestReg) 389 .addFrameIndex(FrameIndex) 390 .addImm(0); 391 } 392 393 /// ReverseBranchCondition - Return the inverse opcode of the 394 /// specified Branch instruction. 395 bool XCoreInstrInfo:: 396 ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const { 397 assert((Cond.size() == 2) && 398 "Invalid XCore branch condition!"); 399 Cond[0].setImm(GetOppositeBranchCondition((XCore::CondCode)Cond[0].getImm())); 400 return false; 401 } 402