XCoreInstrInfo.cpp revision a9ad04191cb56c42944b17980b8b2bb2afe11ab2
1//===- XCoreInstrInfo.cpp - XCore Instruction Information -------*- 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 the XCore implementation of the TargetInstrInfo class. 11// 12//===----------------------------------------------------------------------===// 13 14#include "XCoreMachineFunctionInfo.h" 15#include "XCoreInstrInfo.h" 16#include "XCore.h" 17#include "llvm/ADT/STLExtras.h" 18#include "llvm/CodeGen/MachineInstrBuilder.h" 19#include "llvm/CodeGen/MachineFrameInfo.h" 20#include "llvm/CodeGen/MachineLocation.h" 21#include "llvm/CodeGen/MachineModuleInfo.h" 22#include "XCoreGenInstrInfo.inc" 23#include "llvm/Support/Debug.h" 24#include "llvm/Support/ErrorHandling.h" 25 26namespace llvm { 27namespace XCore { 28 29 // XCore Condition Codes 30 enum CondCode { 31 COND_TRUE, 32 COND_FALSE, 33 COND_INVALID 34 }; 35} 36} 37 38using namespace llvm; 39 40XCoreInstrInfo::XCoreInstrInfo() 41 : TargetInstrInfoImpl(XCoreInsts, array_lengthof(XCoreInsts)), 42 RI(*this) { 43} 44 45static bool isZeroImm(const MachineOperand &op) { 46 return op.isImm() && op.getImm() == 0; 47} 48 49/// Return true if the instruction is a register to register move and 50/// leave the source and dest operands in the passed parameters. 51/// 52bool XCoreInstrInfo::isMoveInstr(const MachineInstr &MI, 53 unsigned &SrcReg, unsigned &DstReg, 54 unsigned &SrcSR, unsigned &DstSR) const { 55 SrcSR = DstSR = 0; // No sub-registers. 56 57 // We look for 4 kinds of patterns here: 58 // add dst, src, 0 59 // sub dst, src, 0 60 // or dst, src, src 61 // and dst, src, src 62 if ((MI.getOpcode() == XCore::ADD_2rus || MI.getOpcode() == XCore::SUB_2rus) 63 && isZeroImm(MI.getOperand(2))) { 64 DstReg = MI.getOperand(0).getReg(); 65 SrcReg = MI.getOperand(1).getReg(); 66 return true; 67 } else if ((MI.getOpcode() == XCore::OR_3r || MI.getOpcode() == XCore::AND_3r) 68 && MI.getOperand(1).getReg() == MI.getOperand(2).getReg()) { 69 DstReg = MI.getOperand(0).getReg(); 70 SrcReg = MI.getOperand(1).getReg(); 71 return true; 72 } 73 return false; 74} 75 76/// isLoadFromStackSlot - If the specified machine instruction is a direct 77/// load from a stack slot, return the virtual or physical register number of 78/// the destination 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 loading from the stack slot. 81unsigned 82XCoreInstrInfo::isLoadFromStackSlot(const MachineInstr *MI, int &FrameIndex) const{ 83 int Opcode = MI->getOpcode(); 84 if (Opcode == XCore::LDWFI) 85 { 86 if ((MI->getOperand(1).isFI()) && // is a stack slot 87 (MI->getOperand(2).isImm()) && // the imm is zero 88 (isZeroImm(MI->getOperand(2)))) 89 { 90 FrameIndex = MI->getOperand(1).getIndex(); 91 return MI->getOperand(0).getReg(); 92 } 93 } 94 return 0; 95} 96 97 /// isStoreToStackSlot - If the specified machine instruction is a direct 98 /// store to a stack slot, return the virtual or physical register number of 99 /// the source reg along with the FrameIndex of the loaded stack slot. If 100 /// not, return 0. This predicate must return 0 if the instruction has 101 /// any side effects other than storing to the stack slot. 102unsigned 103XCoreInstrInfo::isStoreToStackSlot(const MachineInstr *MI, 104 int &FrameIndex) const { 105 int Opcode = MI->getOpcode(); 106 if (Opcode == XCore::STWFI) 107 { 108 if ((MI->getOperand(1).isFI()) && // is a stack slot 109 (MI->getOperand(2).isImm()) && // the imm is zero 110 (isZeroImm(MI->getOperand(2)))) 111 { 112 FrameIndex = MI->getOperand(1).getIndex(); 113 return MI->getOperand(0).getReg(); 114 } 115 } 116 return 0; 117} 118 119/// isInvariantLoad - Return true if the specified instruction (which is marked 120/// mayLoad) is loading from a location whose value is invariant across the 121/// function. For example, loading a value from the constant pool or from 122/// from the argument area of a function if it does not change. This should 123/// only return true of *all* loads the instruction does are invariant (if it 124/// does multiple loads). 125bool 126XCoreInstrInfo::isInvariantLoad(const MachineInstr *MI) const { 127 // Loads from constants pools and loads from invariant argument slots are 128 // invariant 129 int Opcode = MI->getOpcode(); 130 if (Opcode == XCore::LDWCP_ru6 || Opcode == XCore::LDWCP_lru6) { 131 return MI->getOperand(1).isCPI(); 132 } 133 int FrameIndex; 134 if (isLoadFromStackSlot(MI, FrameIndex)) { 135 const MachineFrameInfo &MFI = 136 *MI->getParent()->getParent()->getFrameInfo(); 137 return MFI.isFixedObjectIndex(FrameIndex) && 138 MFI.isImmutableObjectIndex(FrameIndex); 139 } 140 return false; 141} 142 143//===----------------------------------------------------------------------===// 144// Branch Analysis 145//===----------------------------------------------------------------------===// 146 147static inline bool IsBRU(unsigned BrOpc) { 148 return BrOpc == XCore::BRFU_u6 149 || BrOpc == XCore::BRFU_lu6 150 || BrOpc == XCore::BRBU_u6 151 || BrOpc == XCore::BRBU_lu6; 152} 153 154static inline bool IsBRT(unsigned BrOpc) { 155 return BrOpc == XCore::BRFT_ru6 156 || BrOpc == XCore::BRFT_lru6 157 || BrOpc == XCore::BRBT_ru6 158 || BrOpc == XCore::BRBT_lru6; 159} 160 161static inline bool IsBRF(unsigned BrOpc) { 162 return BrOpc == XCore::BRFF_ru6 163 || BrOpc == XCore::BRFF_lru6 164 || BrOpc == XCore::BRBF_ru6 165 || BrOpc == XCore::BRBF_lru6; 166} 167 168static inline bool IsCondBranch(unsigned BrOpc) { 169 return IsBRF(BrOpc) || IsBRT(BrOpc); 170} 171 172/// GetCondFromBranchOpc - Return the XCore CC that matches 173/// the correspondent Branch instruction opcode. 174static XCore::CondCode GetCondFromBranchOpc(unsigned BrOpc) 175{ 176 if (IsBRT(BrOpc)) { 177 return XCore::COND_TRUE; 178 } else if (IsBRF(BrOpc)) { 179 return XCore::COND_FALSE; 180 } else { 181 return XCore::COND_INVALID; 182 } 183} 184 185/// GetCondBranchFromCond - Return the Branch instruction 186/// opcode that matches the cc. 187static inline unsigned GetCondBranchFromCond(XCore::CondCode CC) 188{ 189 switch (CC) { 190 default: llvm_unreachable("Illegal condition code!"); 191 case XCore::COND_TRUE : return XCore::BRFT_lru6; 192 case XCore::COND_FALSE : return XCore::BRFF_lru6; 193 } 194} 195 196/// GetOppositeBranchCondition - Return the inverse of the specified 197/// condition, e.g. turning COND_E to COND_NE. 198static inline XCore::CondCode GetOppositeBranchCondition(XCore::CondCode CC) 199{ 200 switch (CC) { 201 default: llvm_unreachable("Illegal condition code!"); 202 case XCore::COND_TRUE : return XCore::COND_FALSE; 203 case XCore::COND_FALSE : return XCore::COND_TRUE; 204 } 205} 206 207/// AnalyzeBranch - Analyze the branching code at the end of MBB, returning 208/// true if it cannot be understood (e.g. it's a switch dispatch or isn't 209/// implemented for a target). Upon success, this returns false and returns 210/// with the following information in various cases: 211/// 212/// 1. If this block ends with no branches (it just falls through to its succ) 213/// just return false, leaving TBB/FBB null. 214/// 2. If this block ends with only an unconditional branch, it sets TBB to be 215/// the destination block. 216/// 3. If this block ends with an conditional branch and it falls through to 217/// an successor block, it sets TBB to be the branch destination block and a 218/// list of operands that evaluate the condition. These 219/// operands can be passed to other TargetInstrInfo methods to create new 220/// branches. 221/// 4. If this block ends with an conditional branch and an unconditional 222/// block, it returns the 'true' destination in TBB, the 'false' destination 223/// in FBB, and a list of operands that evaluate the condition. These 224/// operands can be passed to other TargetInstrInfo methods to create new 225/// branches. 226/// 227/// Note that RemoveBranch and InsertBranch must be implemented to support 228/// cases where this method returns success. 229/// 230bool 231XCoreInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB, 232 MachineBasicBlock *&FBB, 233 SmallVectorImpl<MachineOperand> &Cond, 234 bool AllowModify) const { 235 // If the block has no terminators, it just falls into the block after it. 236 MachineBasicBlock::iterator I = MBB.end(); 237 if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) 238 return false; 239 240 // Get the last instruction in the block. 241 MachineInstr *LastInst = I; 242 243 // If there is only one terminator instruction, process it. 244 if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) { 245 if (IsBRU(LastInst->getOpcode())) { 246 TBB = LastInst->getOperand(0).getMBB(); 247 return false; 248 } 249 250 XCore::CondCode BranchCode = GetCondFromBranchOpc(LastInst->getOpcode()); 251 if (BranchCode == XCore::COND_INVALID) 252 return true; // Can't handle indirect branch. 253 254 // Conditional branch 255 // Block ends with fall-through condbranch. 256 257 TBB = LastInst->getOperand(1).getMBB(); 258 Cond.push_back(MachineOperand::CreateImm(BranchCode)); 259 Cond.push_back(LastInst->getOperand(0)); 260 return false; 261 } 262 263 // Get the instruction before it if it's a terminator. 264 MachineInstr *SecondLastInst = I; 265 266 // If there are three terminators, we don't know what sort of block this is. 267 if (SecondLastInst && I != MBB.begin() && 268 isUnpredicatedTerminator(--I)) 269 return true; 270 271 unsigned SecondLastOpc = SecondLastInst->getOpcode(); 272 XCore::CondCode BranchCode = GetCondFromBranchOpc(SecondLastOpc); 273 274 // If the block ends with conditional branch followed by unconditional, 275 // handle it. 276 if (BranchCode != XCore::COND_INVALID 277 && IsBRU(LastInst->getOpcode())) { 278 279 TBB = SecondLastInst->getOperand(1).getMBB(); 280 Cond.push_back(MachineOperand::CreateImm(BranchCode)); 281 Cond.push_back(SecondLastInst->getOperand(0)); 282 283 FBB = LastInst->getOperand(0).getMBB(); 284 return false; 285 } 286 287 // If the block ends with two unconditional branches, handle it. The second 288 // one is not executed, so remove it. 289 if (IsBRU(SecondLastInst->getOpcode()) && 290 IsBRU(LastInst->getOpcode())) { 291 TBB = SecondLastInst->getOperand(0).getMBB(); 292 I = LastInst; 293 if (AllowModify) 294 I->eraseFromParent(); 295 return false; 296 } 297 298 // Otherwise, can't handle this. 299 return true; 300} 301 302unsigned 303XCoreInstrInfo::InsertBranch(MachineBasicBlock &MBB,MachineBasicBlock *TBB, 304 MachineBasicBlock *FBB, 305 const SmallVectorImpl<MachineOperand> &Cond)const{ 306 // FIXME there should probably be a DebugLoc argument here 307 DebugLoc dl = DebugLoc::getUnknownLoc(); 308 // Shouldn't be a fall through. 309 assert(TBB && "InsertBranch must not be told to insert a fallthrough"); 310 assert((Cond.size() == 2 || Cond.size() == 0) && 311 "Unexpected number of components!"); 312 313 if (FBB == 0) { // One way branch. 314 if (Cond.empty()) { 315 // Unconditional branch 316 BuildMI(&MBB, dl, get(XCore::BRFU_lu6)).addMBB(TBB); 317 } else { 318 // Conditional branch. 319 unsigned Opc = GetCondBranchFromCond((XCore::CondCode)Cond[0].getImm()); 320 BuildMI(&MBB, dl, get(Opc)).addReg(Cond[1].getReg()) 321 .addMBB(TBB); 322 } 323 return 1; 324 } 325 326 // Two-way Conditional branch. 327 assert(Cond.size() == 2 && "Unexpected number of components!"); 328 unsigned Opc = GetCondBranchFromCond((XCore::CondCode)Cond[0].getImm()); 329 BuildMI(&MBB, dl, get(Opc)).addReg(Cond[1].getReg()) 330 .addMBB(TBB); 331 BuildMI(&MBB, dl, get(XCore::BRFU_lu6)).addMBB(FBB); 332 return 2; 333} 334 335unsigned 336XCoreInstrInfo::RemoveBranch(MachineBasicBlock &MBB) const { 337 MachineBasicBlock::iterator I = MBB.end(); 338 if (I == MBB.begin()) return 0; 339 --I; 340 if (!IsBRU(I->getOpcode()) && !IsCondBranch(I->getOpcode())) 341 return 0; 342 343 // Remove the branch. 344 I->eraseFromParent(); 345 346 I = MBB.end(); 347 348 if (I == MBB.begin()) return 1; 349 --I; 350 if (!IsCondBranch(I->getOpcode())) 351 return 1; 352 353 // Remove the branch. 354 I->eraseFromParent(); 355 return 2; 356} 357 358bool XCoreInstrInfo::copyRegToReg(MachineBasicBlock &MBB, 359 MachineBasicBlock::iterator I, 360 unsigned DestReg, unsigned SrcReg, 361 const TargetRegisterClass *DestRC, 362 const TargetRegisterClass *SrcRC) const { 363 DebugLoc DL = DebugLoc::getUnknownLoc(); 364 if (I != MBB.end()) DL = I->getDebugLoc(); 365 366 if (DestRC == SrcRC) { 367 if (DestRC == XCore::GRRegsRegisterClass) { 368 BuildMI(MBB, I, DL, get(XCore::ADD_2rus), DestReg) 369 .addReg(SrcReg) 370 .addImm(0); 371 return true; 372 } else { 373 return false; 374 } 375 } 376 377 if (SrcRC == XCore::RRegsRegisterClass && SrcReg == XCore::SP && 378 DestRC == XCore::GRRegsRegisterClass) { 379 BuildMI(MBB, I, DL, get(XCore::LDAWSP_ru6), DestReg) 380 .addImm(0); 381 return true; 382 } 383 if (DestRC == XCore::RRegsRegisterClass && DestReg == XCore::SP && 384 SrcRC == XCore::GRRegsRegisterClass) { 385 BuildMI(MBB, I, DL, get(XCore::SETSP_1r)) 386 .addReg(SrcReg); 387 return true; 388 } 389 return false; 390} 391 392void XCoreInstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB, 393 MachineBasicBlock::iterator I, 394 unsigned SrcReg, bool isKill, 395 int FrameIndex, 396 const TargetRegisterClass *RC) const 397{ 398 DebugLoc DL = DebugLoc::getUnknownLoc(); 399 if (I != MBB.end()) DL = I->getDebugLoc(); 400 BuildMI(MBB, I, DL, get(XCore::STWFI)) 401 .addReg(SrcReg, getKillRegState(isKill)) 402 .addFrameIndex(FrameIndex) 403 .addImm(0); 404} 405 406void XCoreInstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB, 407 MachineBasicBlock::iterator I, 408 unsigned DestReg, int FrameIndex, 409 const TargetRegisterClass *RC) const 410{ 411 DebugLoc DL = DebugLoc::getUnknownLoc(); 412 if (I != MBB.end()) DL = I->getDebugLoc(); 413 BuildMI(MBB, I, DL, get(XCore::LDWFI), DestReg) 414 .addFrameIndex(FrameIndex) 415 .addImm(0); 416} 417 418bool XCoreInstrInfo::spillCalleeSavedRegisters(MachineBasicBlock &MBB, 419 MachineBasicBlock::iterator MI, 420 const std::vector<CalleeSavedInfo> &CSI) const 421{ 422 if (CSI.empty()) { 423 return true; 424 } 425 MachineFunction *MF = MBB.getParent(); 426 const MachineFrameInfo *MFI = MF->getFrameInfo(); 427 MachineModuleInfo *MMI = MFI->getMachineModuleInfo(); 428 XCoreFunctionInfo *XFI = MF->getInfo<XCoreFunctionInfo>(); 429 430 bool emitFrameMoves = XCoreRegisterInfo::needsFrameMoves(*MF); 431 432 DebugLoc DL = DebugLoc::getUnknownLoc(); 433 if (MI != MBB.end()) DL = MI->getDebugLoc(); 434 435 for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin(); 436 it != CSI.end(); ++it) { 437 // Add the callee-saved register as live-in. It's killed at the spill. 438 MBB.addLiveIn(it->getReg()); 439 440 storeRegToStackSlot(MBB, MI, it->getReg(), true, 441 it->getFrameIdx(), it->getRegClass()); 442 if (emitFrameMoves) { 443 unsigned SaveLabelId = MMI->NextLabelID(); 444 BuildMI(MBB, MI, DL, get(XCore::DBG_LABEL)).addImm(SaveLabelId); 445 XFI->getSpillLabels().push_back( 446 std::pair<unsigned, CalleeSavedInfo>(SaveLabelId, *it)); 447 } 448 } 449 return true; 450} 451 452bool XCoreInstrInfo::restoreCalleeSavedRegisters(MachineBasicBlock &MBB, 453 MachineBasicBlock::iterator MI, 454 const std::vector<CalleeSavedInfo> &CSI) const 455{ 456 bool AtStart = MI == MBB.begin(); 457 MachineBasicBlock::iterator BeforeI = MI; 458 if (!AtStart) 459 --BeforeI; 460 for (std::vector<CalleeSavedInfo>::const_iterator it = CSI.begin(); 461 it != CSI.end(); ++it) { 462 463 loadRegFromStackSlot(MBB, MI, it->getReg(), 464 it->getFrameIdx(), 465 it->getRegClass()); 466 assert(MI != MBB.begin() && 467 "loadRegFromStackSlot didn't insert any code!"); 468 // Insert in reverse order. loadRegFromStackSlot can insert multiple 469 // instructions. 470 if (AtStart) 471 MI = MBB.begin(); 472 else { 473 MI = BeforeI; 474 ++MI; 475 } 476 } 477 return true; 478} 479 480/// BlockHasNoFallThrough - Analyse if MachineBasicBlock does not 481/// fall-through into its successor block. 482bool XCoreInstrInfo:: 483BlockHasNoFallThrough(const MachineBasicBlock &MBB) const 484{ 485 if (MBB.empty()) return false; 486 487 switch (MBB.back().getOpcode()) { 488 case XCore::RETSP_u6: // Return. 489 case XCore::RETSP_lu6: 490 case XCore::BAU_1r: // Indirect branch. 491 case XCore::BRFU_u6: // Uncond branch. 492 case XCore::BRFU_lu6: 493 case XCore::BRBU_u6: 494 case XCore::BRBU_lu6: 495 return true; 496 default: return false; 497 } 498} 499 500/// ReverseBranchCondition - Return the inverse opcode of the 501/// specified Branch instruction. 502bool XCoreInstrInfo:: 503ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const 504{ 505 assert((Cond.size() == 2) && 506 "Invalid XCore branch condition!"); 507 Cond[0].setImm(GetOppositeBranchCondition((XCore::CondCode)Cond[0].getImm())); 508 return false; 509} 510