1 //===-- MachineFunction.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 // Collect native machine code information for a function. This allows 11 // target-specific information about the generated code to be stored with each 12 // function. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #include "llvm/CodeGen/MachineFunction.h" 17 #include "llvm/ADT/STLExtras.h" 18 #include "llvm/ADT/SmallString.h" 19 #include "llvm/Analysis/ConstantFolding.h" 20 #include "llvm/CodeGen/MachineConstantPool.h" 21 #include "llvm/CodeGen/MachineFrameInfo.h" 22 #include "llvm/CodeGen/MachineFunctionPass.h" 23 #include "llvm/CodeGen/MachineInstr.h" 24 #include "llvm/CodeGen/MachineJumpTableInfo.h" 25 #include "llvm/CodeGen/MachineModuleInfo.h" 26 #include "llvm/CodeGen/MachineRegisterInfo.h" 27 #include "llvm/CodeGen/Passes.h" 28 #include "llvm/IR/DataLayout.h" 29 #include "llvm/IR/DebugInfo.h" 30 #include "llvm/IR/Function.h" 31 #include "llvm/MC/MCAsmInfo.h" 32 #include "llvm/MC/MCContext.h" 33 #include "llvm/Support/Debug.h" 34 #include "llvm/Support/GraphWriter.h" 35 #include "llvm/Support/raw_ostream.h" 36 #include "llvm/Target/TargetFrameLowering.h" 37 #include "llvm/Target/TargetLowering.h" 38 #include "llvm/Target/TargetMachine.h" 39 #include "llvm/Target/TargetSubtargetInfo.h" 40 using namespace llvm; 41 42 #define DEBUG_TYPE "codegen" 43 44 //===----------------------------------------------------------------------===// 45 // MachineFunction implementation 46 //===----------------------------------------------------------------------===// 47 48 // Out of line virtual method. 49 MachineFunctionInfo::~MachineFunctionInfo() {} 50 51 void ilist_traits<MachineBasicBlock>::deleteNode(MachineBasicBlock *MBB) { 52 MBB->getParent()->DeleteMachineBasicBlock(MBB); 53 } 54 55 MachineFunction::MachineFunction(const Function *F, const TargetMachine &TM, 56 unsigned FunctionNum, MachineModuleInfo &mmi) 57 : Fn(F), Target(TM), STI(TM.getSubtargetImpl(*F)), Ctx(mmi.getContext()), 58 MMI(mmi) { 59 if (STI->getRegisterInfo()) 60 RegInfo = new (Allocator) MachineRegisterInfo(this); 61 else 62 RegInfo = nullptr; 63 64 MFInfo = nullptr; 65 FrameInfo = new (Allocator) 66 MachineFrameInfo(STI->getFrameLowering()->getStackAlignment(), 67 STI->getFrameLowering()->isStackRealignable(), 68 !F->hasFnAttribute("no-realign-stack")); 69 70 if (Fn->hasFnAttribute(Attribute::StackAlignment)) 71 FrameInfo->ensureMaxAlignment(Fn->getFnStackAlignment()); 72 73 ConstantPool = new (Allocator) MachineConstantPool(TM); 74 Alignment = STI->getTargetLowering()->getMinFunctionAlignment(); 75 76 // FIXME: Shouldn't use pref alignment if explicit alignment is set on Fn. 77 if (!Fn->hasFnAttribute(Attribute::OptimizeForSize)) 78 Alignment = std::max(Alignment, 79 STI->getTargetLowering()->getPrefFunctionAlignment()); 80 81 FunctionNumber = FunctionNum; 82 JumpTableInfo = nullptr; 83 } 84 85 MachineFunction::~MachineFunction() { 86 // Don't call destructors on MachineInstr and MachineOperand. All of their 87 // memory comes from the BumpPtrAllocator which is about to be purged. 88 // 89 // Do call MachineBasicBlock destructors, it contains std::vectors. 90 for (iterator I = begin(), E = end(); I != E; I = BasicBlocks.erase(I)) 91 I->Insts.clearAndLeakNodesUnsafely(); 92 93 InstructionRecycler.clear(Allocator); 94 OperandRecycler.clear(Allocator); 95 BasicBlockRecycler.clear(Allocator); 96 if (RegInfo) { 97 RegInfo->~MachineRegisterInfo(); 98 Allocator.Deallocate(RegInfo); 99 } 100 if (MFInfo) { 101 MFInfo->~MachineFunctionInfo(); 102 Allocator.Deallocate(MFInfo); 103 } 104 105 FrameInfo->~MachineFrameInfo(); 106 Allocator.Deallocate(FrameInfo); 107 108 ConstantPool->~MachineConstantPool(); 109 Allocator.Deallocate(ConstantPool); 110 111 if (JumpTableInfo) { 112 JumpTableInfo->~MachineJumpTableInfo(); 113 Allocator.Deallocate(JumpTableInfo); 114 } 115 } 116 117 /// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it 118 /// does already exist, allocate one. 119 MachineJumpTableInfo *MachineFunction:: 120 getOrCreateJumpTableInfo(unsigned EntryKind) { 121 if (JumpTableInfo) return JumpTableInfo; 122 123 JumpTableInfo = new (Allocator) 124 MachineJumpTableInfo((MachineJumpTableInfo::JTEntryKind)EntryKind); 125 return JumpTableInfo; 126 } 127 128 /// Should we be emitting segmented stack stuff for the function 129 bool MachineFunction::shouldSplitStack() { 130 return getFunction()->hasFnAttribute("split-stack"); 131 } 132 133 /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and 134 /// recomputes them. This guarantees that the MBB numbers are sequential, 135 /// dense, and match the ordering of the blocks within the function. If a 136 /// specific MachineBasicBlock is specified, only that block and those after 137 /// it are renumbered. 138 void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) { 139 if (empty()) { MBBNumbering.clear(); return; } 140 MachineFunction::iterator MBBI, E = end(); 141 if (MBB == nullptr) 142 MBBI = begin(); 143 else 144 MBBI = MBB; 145 146 // Figure out the block number this should have. 147 unsigned BlockNo = 0; 148 if (MBBI != begin()) 149 BlockNo = std::prev(MBBI)->getNumber() + 1; 150 151 for (; MBBI != E; ++MBBI, ++BlockNo) { 152 if (MBBI->getNumber() != (int)BlockNo) { 153 // Remove use of the old number. 154 if (MBBI->getNumber() != -1) { 155 assert(MBBNumbering[MBBI->getNumber()] == &*MBBI && 156 "MBB number mismatch!"); 157 MBBNumbering[MBBI->getNumber()] = nullptr; 158 } 159 160 // If BlockNo is already taken, set that block's number to -1. 161 if (MBBNumbering[BlockNo]) 162 MBBNumbering[BlockNo]->setNumber(-1); 163 164 MBBNumbering[BlockNo] = MBBI; 165 MBBI->setNumber(BlockNo); 166 } 167 } 168 169 // Okay, all the blocks are renumbered. If we have compactified the block 170 // numbering, shrink MBBNumbering now. 171 assert(BlockNo <= MBBNumbering.size() && "Mismatch!"); 172 MBBNumbering.resize(BlockNo); 173 } 174 175 /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead 176 /// of `new MachineInstr'. 177 /// 178 MachineInstr * 179 MachineFunction::CreateMachineInstr(const MCInstrDesc &MCID, 180 DebugLoc DL, bool NoImp) { 181 return new (InstructionRecycler.Allocate<MachineInstr>(Allocator)) 182 MachineInstr(*this, MCID, DL, NoImp); 183 } 184 185 /// CloneMachineInstr - Create a new MachineInstr which is a copy of the 186 /// 'Orig' instruction, identical in all ways except the instruction 187 /// has no parent, prev, or next. 188 /// 189 MachineInstr * 190 MachineFunction::CloneMachineInstr(const MachineInstr *Orig) { 191 return new (InstructionRecycler.Allocate<MachineInstr>(Allocator)) 192 MachineInstr(*this, *Orig); 193 } 194 195 /// DeleteMachineInstr - Delete the given MachineInstr. 196 /// 197 /// This function also serves as the MachineInstr destructor - the real 198 /// ~MachineInstr() destructor must be empty. 199 void 200 MachineFunction::DeleteMachineInstr(MachineInstr *MI) { 201 // Strip it for parts. The operand array and the MI object itself are 202 // independently recyclable. 203 if (MI->Operands) 204 deallocateOperandArray(MI->CapOperands, MI->Operands); 205 // Don't call ~MachineInstr() which must be trivial anyway because 206 // ~MachineFunction drops whole lists of MachineInstrs wihout calling their 207 // destructors. 208 InstructionRecycler.Deallocate(Allocator, MI); 209 } 210 211 /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this 212 /// instead of `new MachineBasicBlock'. 213 /// 214 MachineBasicBlock * 215 MachineFunction::CreateMachineBasicBlock(const BasicBlock *bb) { 216 return new (BasicBlockRecycler.Allocate<MachineBasicBlock>(Allocator)) 217 MachineBasicBlock(*this, bb); 218 } 219 220 /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock. 221 /// 222 void 223 MachineFunction::DeleteMachineBasicBlock(MachineBasicBlock *MBB) { 224 assert(MBB->getParent() == this && "MBB parent mismatch!"); 225 MBB->~MachineBasicBlock(); 226 BasicBlockRecycler.Deallocate(Allocator, MBB); 227 } 228 229 MachineMemOperand * 230 MachineFunction::getMachineMemOperand(MachinePointerInfo PtrInfo, unsigned f, 231 uint64_t s, unsigned base_alignment, 232 const AAMDNodes &AAInfo, 233 const MDNode *Ranges) { 234 return new (Allocator) MachineMemOperand(PtrInfo, f, s, base_alignment, 235 AAInfo, Ranges); 236 } 237 238 MachineMemOperand * 239 MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO, 240 int64_t Offset, uint64_t Size) { 241 if (MMO->getValue()) 242 return new (Allocator) 243 MachineMemOperand(MachinePointerInfo(MMO->getValue(), 244 MMO->getOffset()+Offset), 245 MMO->getFlags(), Size, 246 MMO->getBaseAlignment()); 247 return new (Allocator) 248 MachineMemOperand(MachinePointerInfo(MMO->getPseudoValue(), 249 MMO->getOffset()+Offset), 250 MMO->getFlags(), Size, 251 MMO->getBaseAlignment()); 252 } 253 254 MachineInstr::mmo_iterator 255 MachineFunction::allocateMemRefsArray(unsigned long Num) { 256 return Allocator.Allocate<MachineMemOperand *>(Num); 257 } 258 259 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator> 260 MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin, 261 MachineInstr::mmo_iterator End) { 262 // Count the number of load mem refs. 263 unsigned Num = 0; 264 for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) 265 if ((*I)->isLoad()) 266 ++Num; 267 268 // Allocate a new array and populate it with the load information. 269 MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num); 270 unsigned Index = 0; 271 for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) { 272 if ((*I)->isLoad()) { 273 if (!(*I)->isStore()) 274 // Reuse the MMO. 275 Result[Index] = *I; 276 else { 277 // Clone the MMO and unset the store flag. 278 MachineMemOperand *JustLoad = 279 getMachineMemOperand((*I)->getPointerInfo(), 280 (*I)->getFlags() & ~MachineMemOperand::MOStore, 281 (*I)->getSize(), (*I)->getBaseAlignment(), 282 (*I)->getAAInfo()); 283 Result[Index] = JustLoad; 284 } 285 ++Index; 286 } 287 } 288 return std::make_pair(Result, Result + Num); 289 } 290 291 std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator> 292 MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin, 293 MachineInstr::mmo_iterator End) { 294 // Count the number of load mem refs. 295 unsigned Num = 0; 296 for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) 297 if ((*I)->isStore()) 298 ++Num; 299 300 // Allocate a new array and populate it with the store information. 301 MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num); 302 unsigned Index = 0; 303 for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) { 304 if ((*I)->isStore()) { 305 if (!(*I)->isLoad()) 306 // Reuse the MMO. 307 Result[Index] = *I; 308 else { 309 // Clone the MMO and unset the load flag. 310 MachineMemOperand *JustStore = 311 getMachineMemOperand((*I)->getPointerInfo(), 312 (*I)->getFlags() & ~MachineMemOperand::MOLoad, 313 (*I)->getSize(), (*I)->getBaseAlignment(), 314 (*I)->getAAInfo()); 315 Result[Index] = JustStore; 316 } 317 ++Index; 318 } 319 } 320 return std::make_pair(Result, Result + Num); 321 } 322 323 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 324 void MachineFunction::dump() const { 325 print(dbgs()); 326 } 327 #endif 328 329 StringRef MachineFunction::getName() const { 330 assert(getFunction() && "No function!"); 331 return getFunction()->getName(); 332 } 333 334 void MachineFunction::print(raw_ostream &OS, SlotIndexes *Indexes) const { 335 OS << "# Machine code for function " << getName() << ": "; 336 if (RegInfo) { 337 OS << (RegInfo->isSSA() ? "SSA" : "Post SSA"); 338 if (!RegInfo->tracksLiveness()) 339 OS << ", not tracking liveness"; 340 } 341 OS << '\n'; 342 343 // Print Frame Information 344 FrameInfo->print(*this, OS); 345 346 // Print JumpTable Information 347 if (JumpTableInfo) 348 JumpTableInfo->print(OS); 349 350 // Print Constant Pool 351 ConstantPool->print(OS); 352 353 const TargetRegisterInfo *TRI = getSubtarget().getRegisterInfo(); 354 355 if (RegInfo && !RegInfo->livein_empty()) { 356 OS << "Function Live Ins: "; 357 for (MachineRegisterInfo::livein_iterator 358 I = RegInfo->livein_begin(), E = RegInfo->livein_end(); I != E; ++I) { 359 OS << PrintReg(I->first, TRI); 360 if (I->second) 361 OS << " in " << PrintReg(I->second, TRI); 362 if (std::next(I) != E) 363 OS << ", "; 364 } 365 OS << '\n'; 366 } 367 368 for (const auto &BB : *this) { 369 OS << '\n'; 370 BB.print(OS, Indexes); 371 } 372 373 OS << "\n# End machine code for function " << getName() << ".\n\n"; 374 } 375 376 namespace llvm { 377 template<> 378 struct DOTGraphTraits<const MachineFunction*> : public DefaultDOTGraphTraits { 379 380 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 381 382 static std::string getGraphName(const MachineFunction *F) { 383 return ("CFG for '" + F->getName() + "' function").str(); 384 } 385 386 std::string getNodeLabel(const MachineBasicBlock *Node, 387 const MachineFunction *Graph) { 388 std::string OutStr; 389 { 390 raw_string_ostream OSS(OutStr); 391 392 if (isSimple()) { 393 OSS << "BB#" << Node->getNumber(); 394 if (const BasicBlock *BB = Node->getBasicBlock()) 395 OSS << ": " << BB->getName(); 396 } else 397 Node->print(OSS); 398 } 399 400 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 401 402 // Process string output to make it nicer... 403 for (unsigned i = 0; i != OutStr.length(); ++i) 404 if (OutStr[i] == '\n') { // Left justify 405 OutStr[i] = '\\'; 406 OutStr.insert(OutStr.begin()+i+1, 'l'); 407 } 408 return OutStr; 409 } 410 }; 411 } 412 413 void MachineFunction::viewCFG() const 414 { 415 #ifndef NDEBUG 416 ViewGraph(this, "mf" + getName()); 417 #else 418 errs() << "MachineFunction::viewCFG is only available in debug builds on " 419 << "systems with Graphviz or gv!\n"; 420 #endif // NDEBUG 421 } 422 423 void MachineFunction::viewCFGOnly() const 424 { 425 #ifndef NDEBUG 426 ViewGraph(this, "mf" + getName(), true); 427 #else 428 errs() << "MachineFunction::viewCFGOnly is only available in debug builds on " 429 << "systems with Graphviz or gv!\n"; 430 #endif // NDEBUG 431 } 432 433 /// addLiveIn - Add the specified physical register as a live-in value and 434 /// create a corresponding virtual register for it. 435 unsigned MachineFunction::addLiveIn(unsigned PReg, 436 const TargetRegisterClass *RC) { 437 MachineRegisterInfo &MRI = getRegInfo(); 438 unsigned VReg = MRI.getLiveInVirtReg(PReg); 439 if (VReg) { 440 const TargetRegisterClass *VRegRC = MRI.getRegClass(VReg); 441 (void)VRegRC; 442 // A physical register can be added several times. 443 // Between two calls, the register class of the related virtual register 444 // may have been constrained to match some operation constraints. 445 // In that case, check that the current register class includes the 446 // physical register and is a sub class of the specified RC. 447 assert((VRegRC == RC || (VRegRC->contains(PReg) && 448 RC->hasSubClassEq(VRegRC))) && 449 "Register class mismatch!"); 450 return VReg; 451 } 452 VReg = MRI.createVirtualRegister(RC); 453 MRI.addLiveIn(PReg, VReg); 454 return VReg; 455 } 456 457 /// getJTISymbol - Return the MCSymbol for the specified non-empty jump table. 458 /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a 459 /// normal 'L' label is returned. 460 MCSymbol *MachineFunction::getJTISymbol(unsigned JTI, MCContext &Ctx, 461 bool isLinkerPrivate) const { 462 const DataLayout *DL = getTarget().getDataLayout(); 463 assert(JumpTableInfo && "No jump tables"); 464 assert(JTI < JumpTableInfo->getJumpTables().size() && "Invalid JTI!"); 465 466 const char *Prefix = isLinkerPrivate ? DL->getLinkerPrivateGlobalPrefix() : 467 DL->getPrivateGlobalPrefix(); 468 SmallString<60> Name; 469 raw_svector_ostream(Name) 470 << Prefix << "JTI" << getFunctionNumber() << '_' << JTI; 471 return Ctx.GetOrCreateSymbol(Name); 472 } 473 474 /// getPICBaseSymbol - Return a function-local symbol to represent the PIC 475 /// base. 476 MCSymbol *MachineFunction::getPICBaseSymbol() const { 477 const DataLayout *DL = getTarget().getDataLayout(); 478 return Ctx.GetOrCreateSymbol(Twine(DL->getPrivateGlobalPrefix())+ 479 Twine(getFunctionNumber())+"$pb"); 480 } 481 482 //===----------------------------------------------------------------------===// 483 // MachineFrameInfo implementation 484 //===----------------------------------------------------------------------===// 485 486 /// ensureMaxAlignment - Make sure the function is at least Align bytes 487 /// aligned. 488 void MachineFrameInfo::ensureMaxAlignment(unsigned Align) { 489 if (!StackRealignable || !RealignOption) 490 assert(Align <= StackAlignment && 491 "For targets without stack realignment, Align is out of limit!"); 492 if (MaxAlignment < Align) MaxAlignment = Align; 493 } 494 495 /// clampStackAlignment - Clamp the alignment if requested and emit a warning. 496 static inline unsigned clampStackAlignment(bool ShouldClamp, unsigned Align, 497 unsigned StackAlign) { 498 if (!ShouldClamp || Align <= StackAlign) 499 return Align; 500 DEBUG(dbgs() << "Warning: requested alignment " << Align 501 << " exceeds the stack alignment " << StackAlign 502 << " when stack realignment is off" << '\n'); 503 return StackAlign; 504 } 505 506 /// CreateStackObject - Create a new statically sized stack object, returning 507 /// a nonnegative identifier to represent it. 508 /// 509 int MachineFrameInfo::CreateStackObject(uint64_t Size, unsigned Alignment, 510 bool isSS, const AllocaInst *Alloca) { 511 assert(Size != 0 && "Cannot allocate zero size stack objects!"); 512 Alignment = clampStackAlignment(!StackRealignable || !RealignOption, 513 Alignment, StackAlignment); 514 Objects.push_back(StackObject(Size, Alignment, 0, false, isSS, Alloca, 515 !isSS)); 516 int Index = (int)Objects.size() - NumFixedObjects - 1; 517 assert(Index >= 0 && "Bad frame index!"); 518 ensureMaxAlignment(Alignment); 519 return Index; 520 } 521 522 /// CreateSpillStackObject - Create a new statically sized stack object that 523 /// represents a spill slot, returning a nonnegative identifier to represent 524 /// it. 525 /// 526 int MachineFrameInfo::CreateSpillStackObject(uint64_t Size, 527 unsigned Alignment) { 528 Alignment = clampStackAlignment(!StackRealignable || !RealignOption, 529 Alignment, StackAlignment); 530 CreateStackObject(Size, Alignment, true); 531 int Index = (int)Objects.size() - NumFixedObjects - 1; 532 ensureMaxAlignment(Alignment); 533 return Index; 534 } 535 536 /// CreateVariableSizedObject - Notify the MachineFrameInfo object that a 537 /// variable sized object has been created. This must be created whenever a 538 /// variable sized object is created, whether or not the index returned is 539 /// actually used. 540 /// 541 int MachineFrameInfo::CreateVariableSizedObject(unsigned Alignment, 542 const AllocaInst *Alloca) { 543 HasVarSizedObjects = true; 544 Alignment = clampStackAlignment(!StackRealignable || !RealignOption, 545 Alignment, StackAlignment); 546 Objects.push_back(StackObject(0, Alignment, 0, false, false, Alloca, true)); 547 ensureMaxAlignment(Alignment); 548 return (int)Objects.size()-NumFixedObjects-1; 549 } 550 551 /// CreateFixedObject - Create a new object at a fixed location on the stack. 552 /// All fixed objects should be created before other objects are created for 553 /// efficiency. By default, fixed objects are immutable. This returns an 554 /// index with a negative value. 555 /// 556 int MachineFrameInfo::CreateFixedObject(uint64_t Size, int64_t SPOffset, 557 bool Immutable, bool isAliased) { 558 assert(Size != 0 && "Cannot allocate zero size fixed stack objects!"); 559 // The alignment of the frame index can be determined from its offset from 560 // the incoming frame position. If the frame object is at offset 32 and 561 // the stack is guaranteed to be 16-byte aligned, then we know that the 562 // object is 16-byte aligned. 563 unsigned Align = MinAlign(SPOffset, StackAlignment); 564 Align = clampStackAlignment(!StackRealignable || !RealignOption, Align, 565 StackAlignment); 566 Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, Immutable, 567 /*isSS*/ false, 568 /*Alloca*/ nullptr, isAliased)); 569 return -++NumFixedObjects; 570 } 571 572 /// CreateFixedSpillStackObject - Create a spill slot at a fixed location 573 /// on the stack. Returns an index with a negative value. 574 int MachineFrameInfo::CreateFixedSpillStackObject(uint64_t Size, 575 int64_t SPOffset) { 576 unsigned Align = MinAlign(SPOffset, StackAlignment); 577 Align = clampStackAlignment(!StackRealignable || !RealignOption, Align, 578 StackAlignment); 579 Objects.insert(Objects.begin(), StackObject(Size, Align, SPOffset, 580 /*Immutable*/ true, 581 /*isSS*/ true, 582 /*Alloca*/ nullptr, 583 /*isAliased*/ false)); 584 return -++NumFixedObjects; 585 } 586 587 BitVector 588 MachineFrameInfo::getPristineRegs(const MachineBasicBlock *MBB) const { 589 assert(MBB && "MBB must be valid"); 590 const MachineFunction *MF = MBB->getParent(); 591 assert(MF && "MBB must be part of a MachineFunction"); 592 const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo(); 593 BitVector BV(TRI->getNumRegs()); 594 595 // Before CSI is calculated, no registers are considered pristine. They can be 596 // freely used and PEI will make sure they are saved. 597 if (!isCalleeSavedInfoValid()) 598 return BV; 599 600 for (const MCPhysReg *CSR = TRI->getCalleeSavedRegs(MF); CSR && *CSR; ++CSR) 601 BV.set(*CSR); 602 603 // The entry MBB always has all CSRs pristine. 604 if (MBB == &MF->front()) 605 return BV; 606 607 // On other MBBs the saved CSRs are not pristine. 608 const std::vector<CalleeSavedInfo> &CSI = getCalleeSavedInfo(); 609 for (std::vector<CalleeSavedInfo>::const_iterator I = CSI.begin(), 610 E = CSI.end(); I != E; ++I) 611 BV.reset(I->getReg()); 612 613 return BV; 614 } 615 616 unsigned MachineFrameInfo::estimateStackSize(const MachineFunction &MF) const { 617 const TargetFrameLowering *TFI = MF.getSubtarget().getFrameLowering(); 618 const TargetRegisterInfo *RegInfo = MF.getSubtarget().getRegisterInfo(); 619 unsigned MaxAlign = getMaxAlignment(); 620 int Offset = 0; 621 622 // This code is very, very similar to PEI::calculateFrameObjectOffsets(). 623 // It really should be refactored to share code. Until then, changes 624 // should keep in mind that there's tight coupling between the two. 625 626 for (int i = getObjectIndexBegin(); i != 0; ++i) { 627 int FixedOff = -getObjectOffset(i); 628 if (FixedOff > Offset) Offset = FixedOff; 629 } 630 for (unsigned i = 0, e = getObjectIndexEnd(); i != e; ++i) { 631 if (isDeadObjectIndex(i)) 632 continue; 633 Offset += getObjectSize(i); 634 unsigned Align = getObjectAlignment(i); 635 // Adjust to alignment boundary 636 Offset = (Offset+Align-1)/Align*Align; 637 638 MaxAlign = std::max(Align, MaxAlign); 639 } 640 641 if (adjustsStack() && TFI->hasReservedCallFrame(MF)) 642 Offset += getMaxCallFrameSize(); 643 644 // Round up the size to a multiple of the alignment. If the function has 645 // any calls or alloca's, align to the target's StackAlignment value to 646 // ensure that the callee's frame or the alloca data is suitably aligned; 647 // otherwise, for leaf functions, align to the TransientStackAlignment 648 // value. 649 unsigned StackAlign; 650 if (adjustsStack() || hasVarSizedObjects() || 651 (RegInfo->needsStackRealignment(MF) && getObjectIndexEnd() != 0)) 652 StackAlign = TFI->getStackAlignment(); 653 else 654 StackAlign = TFI->getTransientStackAlignment(); 655 656 // If the frame pointer is eliminated, all frame offsets will be relative to 657 // SP not FP. Align to MaxAlign so this works. 658 StackAlign = std::max(StackAlign, MaxAlign); 659 unsigned AlignMask = StackAlign - 1; 660 Offset = (Offset + AlignMask) & ~uint64_t(AlignMask); 661 662 return (unsigned)Offset; 663 } 664 665 void MachineFrameInfo::print(const MachineFunction &MF, raw_ostream &OS) const{ 666 if (Objects.empty()) return; 667 668 const TargetFrameLowering *FI = MF.getSubtarget().getFrameLowering(); 669 int ValOffset = (FI ? FI->getOffsetOfLocalArea() : 0); 670 671 OS << "Frame Objects:\n"; 672 673 for (unsigned i = 0, e = Objects.size(); i != e; ++i) { 674 const StackObject &SO = Objects[i]; 675 OS << " fi#" << (int)(i-NumFixedObjects) << ": "; 676 if (SO.Size == ~0ULL) { 677 OS << "dead\n"; 678 continue; 679 } 680 if (SO.Size == 0) 681 OS << "variable sized"; 682 else 683 OS << "size=" << SO.Size; 684 OS << ", align=" << SO.Alignment; 685 686 if (i < NumFixedObjects) 687 OS << ", fixed"; 688 if (i < NumFixedObjects || SO.SPOffset != -1) { 689 int64_t Off = SO.SPOffset - ValOffset; 690 OS << ", at location [SP"; 691 if (Off > 0) 692 OS << "+" << Off; 693 else if (Off < 0) 694 OS << Off; 695 OS << "]"; 696 } 697 OS << "\n"; 698 } 699 } 700 701 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 702 void MachineFrameInfo::dump(const MachineFunction &MF) const { 703 print(MF, dbgs()); 704 } 705 #endif 706 707 //===----------------------------------------------------------------------===// 708 // MachineJumpTableInfo implementation 709 //===----------------------------------------------------------------------===// 710 711 /// getEntrySize - Return the size of each entry in the jump table. 712 unsigned MachineJumpTableInfo::getEntrySize(const DataLayout &TD) const { 713 // The size of a jump table entry is 4 bytes unless the entry is just the 714 // address of a block, in which case it is the pointer size. 715 switch (getEntryKind()) { 716 case MachineJumpTableInfo::EK_BlockAddress: 717 return TD.getPointerSize(); 718 case MachineJumpTableInfo::EK_GPRel64BlockAddress: 719 return 8; 720 case MachineJumpTableInfo::EK_GPRel32BlockAddress: 721 case MachineJumpTableInfo::EK_LabelDifference32: 722 case MachineJumpTableInfo::EK_Custom32: 723 return 4; 724 case MachineJumpTableInfo::EK_Inline: 725 return 0; 726 } 727 llvm_unreachable("Unknown jump table encoding!"); 728 } 729 730 /// getEntryAlignment - Return the alignment of each entry in the jump table. 731 unsigned MachineJumpTableInfo::getEntryAlignment(const DataLayout &TD) const { 732 // The alignment of a jump table entry is the alignment of int32 unless the 733 // entry is just the address of a block, in which case it is the pointer 734 // alignment. 735 switch (getEntryKind()) { 736 case MachineJumpTableInfo::EK_BlockAddress: 737 return TD.getPointerABIAlignment(); 738 case MachineJumpTableInfo::EK_GPRel64BlockAddress: 739 return TD.getABIIntegerTypeAlignment(64); 740 case MachineJumpTableInfo::EK_GPRel32BlockAddress: 741 case MachineJumpTableInfo::EK_LabelDifference32: 742 case MachineJumpTableInfo::EK_Custom32: 743 return TD.getABIIntegerTypeAlignment(32); 744 case MachineJumpTableInfo::EK_Inline: 745 return 1; 746 } 747 llvm_unreachable("Unknown jump table encoding!"); 748 } 749 750 /// createJumpTableIndex - Create a new jump table entry in the jump table info. 751 /// 752 unsigned MachineJumpTableInfo::createJumpTableIndex( 753 const std::vector<MachineBasicBlock*> &DestBBs) { 754 assert(!DestBBs.empty() && "Cannot create an empty jump table!"); 755 JumpTables.push_back(MachineJumpTableEntry(DestBBs)); 756 return JumpTables.size()-1; 757 } 758 759 /// ReplaceMBBInJumpTables - If Old is the target of any jump tables, update 760 /// the jump tables to branch to New instead. 761 bool MachineJumpTableInfo::ReplaceMBBInJumpTables(MachineBasicBlock *Old, 762 MachineBasicBlock *New) { 763 assert(Old != New && "Not making a change?"); 764 bool MadeChange = false; 765 for (size_t i = 0, e = JumpTables.size(); i != e; ++i) 766 ReplaceMBBInJumpTable(i, Old, New); 767 return MadeChange; 768 } 769 770 /// ReplaceMBBInJumpTable - If Old is a target of the jump tables, update 771 /// the jump table to branch to New instead. 772 bool MachineJumpTableInfo::ReplaceMBBInJumpTable(unsigned Idx, 773 MachineBasicBlock *Old, 774 MachineBasicBlock *New) { 775 assert(Old != New && "Not making a change?"); 776 bool MadeChange = false; 777 MachineJumpTableEntry &JTE = JumpTables[Idx]; 778 for (size_t j = 0, e = JTE.MBBs.size(); j != e; ++j) 779 if (JTE.MBBs[j] == Old) { 780 JTE.MBBs[j] = New; 781 MadeChange = true; 782 } 783 return MadeChange; 784 } 785 786 void MachineJumpTableInfo::print(raw_ostream &OS) const { 787 if (JumpTables.empty()) return; 788 789 OS << "Jump Tables:\n"; 790 791 for (unsigned i = 0, e = JumpTables.size(); i != e; ++i) { 792 OS << " jt#" << i << ": "; 793 for (unsigned j = 0, f = JumpTables[i].MBBs.size(); j != f; ++j) 794 OS << " BB#" << JumpTables[i].MBBs[j]->getNumber(); 795 } 796 797 OS << '\n'; 798 } 799 800 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 801 void MachineJumpTableInfo::dump() const { print(dbgs()); } 802 #endif 803 804 805 //===----------------------------------------------------------------------===// 806 // MachineConstantPool implementation 807 //===----------------------------------------------------------------------===// 808 809 void MachineConstantPoolValue::anchor() { } 810 811 const DataLayout *MachineConstantPool::getDataLayout() const { 812 return TM.getDataLayout(); 813 } 814 815 Type *MachineConstantPoolEntry::getType() const { 816 if (isMachineConstantPoolEntry()) 817 return Val.MachineCPVal->getType(); 818 return Val.ConstVal->getType(); 819 } 820 821 822 unsigned MachineConstantPoolEntry::getRelocationInfo() const { 823 if (isMachineConstantPoolEntry()) 824 return Val.MachineCPVal->getRelocationInfo(); 825 return Val.ConstVal->getRelocationInfo(); 826 } 827 828 SectionKind 829 MachineConstantPoolEntry::getSectionKind(const DataLayout *DL) const { 830 SectionKind Kind; 831 switch (getRelocationInfo()) { 832 default: 833 llvm_unreachable("Unknown section kind"); 834 case Constant::GlobalRelocations: 835 Kind = SectionKind::getReadOnlyWithRel(); 836 break; 837 case Constant::LocalRelocation: 838 Kind = SectionKind::getReadOnlyWithRelLocal(); 839 break; 840 case Constant::NoRelocation: 841 switch (DL->getTypeAllocSize(getType())) { 842 case 4: 843 Kind = SectionKind::getMergeableConst4(); 844 break; 845 case 8: 846 Kind = SectionKind::getMergeableConst8(); 847 break; 848 case 16: 849 Kind = SectionKind::getMergeableConst16(); 850 break; 851 default: 852 Kind = SectionKind::getReadOnly(); 853 break; 854 } 855 } 856 return Kind; 857 } 858 859 MachineConstantPool::~MachineConstantPool() { 860 for (unsigned i = 0, e = Constants.size(); i != e; ++i) 861 if (Constants[i].isMachineConstantPoolEntry()) 862 delete Constants[i].Val.MachineCPVal; 863 for (DenseSet<MachineConstantPoolValue*>::iterator I = 864 MachineCPVsSharingEntries.begin(), E = MachineCPVsSharingEntries.end(); 865 I != E; ++I) 866 delete *I; 867 } 868 869 /// CanShareConstantPoolEntry - Test whether the given two constants 870 /// can be allocated the same constant pool entry. 871 static bool CanShareConstantPoolEntry(const Constant *A, const Constant *B, 872 const DataLayout *TD) { 873 // Handle the trivial case quickly. 874 if (A == B) return true; 875 876 // If they have the same type but weren't the same constant, quickly 877 // reject them. 878 if (A->getType() == B->getType()) return false; 879 880 // We can't handle structs or arrays. 881 if (isa<StructType>(A->getType()) || isa<ArrayType>(A->getType()) || 882 isa<StructType>(B->getType()) || isa<ArrayType>(B->getType())) 883 return false; 884 885 // For now, only support constants with the same size. 886 uint64_t StoreSize = TD->getTypeStoreSize(A->getType()); 887 if (StoreSize != TD->getTypeStoreSize(B->getType()) || StoreSize > 128) 888 return false; 889 890 Type *IntTy = IntegerType::get(A->getContext(), StoreSize*8); 891 892 // Try constant folding a bitcast of both instructions to an integer. If we 893 // get two identical ConstantInt's, then we are good to share them. We use 894 // the constant folding APIs to do this so that we get the benefit of 895 // DataLayout. 896 if (isa<PointerType>(A->getType())) 897 A = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy, 898 const_cast<Constant *>(A), *TD); 899 else if (A->getType() != IntTy) 900 A = ConstantFoldInstOperands(Instruction::BitCast, IntTy, 901 const_cast<Constant *>(A), *TD); 902 if (isa<PointerType>(B->getType())) 903 B = ConstantFoldInstOperands(Instruction::PtrToInt, IntTy, 904 const_cast<Constant *>(B), *TD); 905 else if (B->getType() != IntTy) 906 B = ConstantFoldInstOperands(Instruction::BitCast, IntTy, 907 const_cast<Constant *>(B), *TD); 908 909 return A == B; 910 } 911 912 /// getConstantPoolIndex - Create a new entry in the constant pool or return 913 /// an existing one. User must specify the log2 of the minimum required 914 /// alignment for the object. 915 /// 916 unsigned MachineConstantPool::getConstantPoolIndex(const Constant *C, 917 unsigned Alignment) { 918 assert(Alignment && "Alignment must be specified!"); 919 if (Alignment > PoolAlignment) PoolAlignment = Alignment; 920 921 // Check to see if we already have this constant. 922 // 923 // FIXME, this could be made much more efficient for large constant pools. 924 for (unsigned i = 0, e = Constants.size(); i != e; ++i) 925 if (!Constants[i].isMachineConstantPoolEntry() && 926 CanShareConstantPoolEntry(Constants[i].Val.ConstVal, C, 927 getDataLayout())) { 928 if ((unsigned)Constants[i].getAlignment() < Alignment) 929 Constants[i].Alignment = Alignment; 930 return i; 931 } 932 933 Constants.push_back(MachineConstantPoolEntry(C, Alignment)); 934 return Constants.size()-1; 935 } 936 937 unsigned MachineConstantPool::getConstantPoolIndex(MachineConstantPoolValue *V, 938 unsigned Alignment) { 939 assert(Alignment && "Alignment must be specified!"); 940 if (Alignment > PoolAlignment) PoolAlignment = Alignment; 941 942 // Check to see if we already have this constant. 943 // 944 // FIXME, this could be made much more efficient for large constant pools. 945 int Idx = V->getExistingMachineCPValue(this, Alignment); 946 if (Idx != -1) { 947 MachineCPVsSharingEntries.insert(V); 948 return (unsigned)Idx; 949 } 950 951 Constants.push_back(MachineConstantPoolEntry(V, Alignment)); 952 return Constants.size()-1; 953 } 954 955 void MachineConstantPool::print(raw_ostream &OS) const { 956 if (Constants.empty()) return; 957 958 OS << "Constant Pool:\n"; 959 for (unsigned i = 0, e = Constants.size(); i != e; ++i) { 960 OS << " cp#" << i << ": "; 961 if (Constants[i].isMachineConstantPoolEntry()) 962 Constants[i].Val.MachineCPVal->print(OS); 963 else 964 Constants[i].Val.ConstVal->printAsOperand(OS, /*PrintType=*/false); 965 OS << ", align=" << Constants[i].getAlignment(); 966 OS << "\n"; 967 } 968 } 969 970 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) 971 void MachineConstantPool::dump() const { print(dbgs()); } 972 #endif 973