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