src/llvm/include/llvm/CodeGen/MachineFunction.h

   1 //===-- llvm/CodeGen/MachineFunction.h --------------------------*- 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 // Collect native machine code for a function.  This class contains a list of
  11 // MachineBasicBlock instances that make up the current compiled function.
  12 //
  13 // This class also contains pointers to various classes which hold
  14 // target-specific information about the generated code.
  15 //
  16 //===----------------------------------------------------------------------===//
  17
  18 #ifndef LLVM_CODEGEN_MACHINEFUNCTION_H
  19 #define LLVM_CODEGEN_MACHINEFUNCTION_H
  20
  21 #include "llvm/ADT/ilist.h"
  22 #include "llvm/CodeGen/MachineBasicBlock.h"
  23 #include "llvm/IR/DebugLoc.h"
  24 #include "llvm/IR/Metadata.h"
  25 #include "llvm/Support/Allocator.h"
  26 #include "llvm/Support/ArrayRecycler.h"
  27 #include "llvm/Support/Recycler.h"
  28
  29 namespace llvm {
  30
  31 class Value;
  32 class Function;
  33 class GCModuleInfo;
  34 class MachineRegisterInfo;
  35 class MachineFrameInfo;
  36 class MachineConstantPool;
  37 class MachineJumpTableInfo;
  38 class MachineModuleInfo;
  39 class MCContext;
  40 class Pass;
  41 class TargetMachine;
  42 class TargetSubtargetInfo;
  43 class TargetRegisterClass;
  44 struct MachinePointerInfo;
  45
  46 template <>
  47 struct ilist_traits<MachineBasicBlock>
  48     : public ilist_default_traits<MachineBasicBlock> {
  49   mutable ilist_half_node<MachineBasicBlock> Sentinel;
  50 public:
  51   MachineBasicBlock *createSentinel() const {
  52     return static_cast<MachineBasicBlock*>(&Sentinel);
  53   }
  54   void destroySentinel(MachineBasicBlock *) const {}
  55
  56   MachineBasicBlock *provideInitialHead() const { return createSentinel(); }
  57   MachineBasicBlock *ensureHead(MachineBasicBlock*) const {
  58     return createSentinel();
  59   }
  60   static void noteHead(MachineBasicBlock*, MachineBasicBlock*) {}
  61
  62   void addNodeToList(MachineBasicBlock* MBB);
  63   void removeNodeFromList(MachineBasicBlock* MBB);
  64   void deleteNode(MachineBasicBlock *MBB);
  65 private:
  66   void createNode(const MachineBasicBlock &);
  67 };
  68
  69 /// MachineFunctionInfo - This class can be derived from and used by targets to
  70 /// hold private target-specific information for each MachineFunction.  Objects
  71 /// of type are accessed/created with MF::getInfo and destroyed when the
  72 /// MachineFunction is destroyed.
  73 struct MachineFunctionInfo {
  74   virtual ~MachineFunctionInfo();
  75
  76   /// \brief Factory function: default behavior is to call new using the
  77   /// supplied allocator.
  78   ///
  79   /// This function can be overridden in a derive class.
  80   template<typename Ty>
  81   static Ty *create(BumpPtrAllocator &Allocator, MachineFunction &MF) {
  82     return new (Allocator.Allocate<Ty>()) Ty(MF);
  83   }
  84 };
  85
  86 class MachineFunction {
  87   const Function *Fn;
  88   const TargetMachine &Target;
  89   const TargetSubtargetInfo *STI;
  90   MCContext &Ctx;
  91   MachineModuleInfo &MMI;
  92
  93   // RegInfo - Information about each register in use in the function.
  94   MachineRegisterInfo *RegInfo;
  95
  96   // Used to keep track of target-specific per-machine function information for
  97   // the target implementation.
  98   MachineFunctionInfo *MFInfo;
  99
 100   // Keep track of objects allocated on the stack.
 101   MachineFrameInfo *FrameInfo;
 102
 103   // Keep track of constants which are spilled to memory
 104   MachineConstantPool *ConstantPool;
 105
 106   // Keep track of jump tables for switch instructions
 107   MachineJumpTableInfo *JumpTableInfo;
 108
 109   // Function-level unique numbering for MachineBasicBlocks.  When a
 110   // MachineBasicBlock is inserted into a MachineFunction is it automatically
 111   // numbered and this vector keeps track of the mapping from ID's to MBB's.
 112   std::vector<MachineBasicBlock*> MBBNumbering;
 113
 114   // Pool-allocate MachineFunction-lifetime and IR objects.
 115   BumpPtrAllocator Allocator;
 116
 117   // Allocation management for instructions in function.
 118   Recycler<MachineInstr> InstructionRecycler;
 119
 120   // Allocation management for operand arrays on instructions.
 121   ArrayRecycler<MachineOperand> OperandRecycler;
 122
 123   // Allocation management for basic blocks in function.
 124   Recycler<MachineBasicBlock> BasicBlockRecycler;
 125
 126   // List of machine basic blocks in function
 127   typedef ilist<MachineBasicBlock> BasicBlockListType;
 128   BasicBlockListType BasicBlocks;
 129
 130   /// FunctionNumber - This provides a unique ID for each function emitted in
 131   /// this translation unit.
 132   ///
 133   unsigned FunctionNumber;
 134
 135   /// Alignment - The alignment of the function.
 136   unsigned Alignment;
 137
 138   /// ExposesReturnsTwice - True if the function calls setjmp or related
 139   /// functions with attribute "returns twice", but doesn't have
 140   /// the attribute itself.
 141   /// This is used to limit optimizations which cannot reason
 142   /// about the control flow of such functions.
 143   bool ExposesReturnsTwice;
 144
 145   /// True if the function includes any inline assembly.
 146   bool HasInlineAsm;
 147
 148   MachineFunction(const MachineFunction &) LLVM_DELETED_FUNCTION;
 149   void operator=(const MachineFunction&) LLVM_DELETED_FUNCTION;
 150 public:
 151   MachineFunction(const Function *Fn, const TargetMachine &TM,
 152                   unsigned FunctionNum, MachineModuleInfo &MMI);
 153   ~MachineFunction();
 154
 155   MachineModuleInfo &getMMI() const { return MMI; }
 156   MCContext &getContext() const { return Ctx; }
 157
 158   /// getFunction - Return the LLVM function that this machine code represents
 159   ///
 160   const Function *getFunction() const { return Fn; }
 161
 162   /// getName - Return the name of the corresponding LLVM function.
 163   ///
 164   StringRef getName() const;
 165
 166   /// getFunctionNumber - Return a unique ID for the current function.
 167   ///
 168   unsigned getFunctionNumber() const { return FunctionNumber; }
 169
 170   /// getTarget - Return the target machine this machine code is compiled with
 171   ///
 172   const TargetMachine &getTarget() const { return Target; }
 173
 174   /// getSubtarget - Return the subtarget for which this machine code is being
 175   /// compiled.
 176   const TargetSubtargetInfo &getSubtarget() const { return *STI; }
 177   void setSubtarget(const TargetSubtargetInfo *ST) { STI = ST; }
 178
 179   /// getRegInfo - Return information about the registers currently in use.
 180   ///
 181   MachineRegisterInfo &getRegInfo() { return *RegInfo; }
 182   const MachineRegisterInfo &getRegInfo() const { return *RegInfo; }
 183
 184   /// getFrameInfo - Return the frame info object for the current function.
 185   /// This object contains information about objects allocated on the stack
 186   /// frame of the current function in an abstract way.
 187   ///
 188   MachineFrameInfo *getFrameInfo() { return FrameInfo; }
 189   const MachineFrameInfo *getFrameInfo() const { return FrameInfo; }
 190
 191   /// getJumpTableInfo - Return the jump table info object for the current
 192   /// function.  This object contains information about jump tables in the
 193   /// current function.  If the current function has no jump tables, this will
 194   /// return null.
 195   const MachineJumpTableInfo *getJumpTableInfo() const { return JumpTableInfo; }
 196   MachineJumpTableInfo *getJumpTableInfo() { return JumpTableInfo; }
 197
 198   /// getOrCreateJumpTableInfo - Get the JumpTableInfo for this function, if it
 199   /// does already exist, allocate one.
 200   MachineJumpTableInfo *getOrCreateJumpTableInfo(unsigned JTEntryKind);
 201
 202
 203   /// getConstantPool - Return the constant pool object for the current
 204   /// function.
 205   ///
 206   MachineConstantPool *getConstantPool() { return ConstantPool; }
 207   const MachineConstantPool *getConstantPool() const { return ConstantPool; }
 208
 209   /// getAlignment - Return the alignment (log2, not bytes) of the function.
 210   ///
 211   unsigned getAlignment() const { return Alignment; }
 212
 213   /// setAlignment - Set the alignment (log2, not bytes) of the function.
 214   ///
 215   void setAlignment(unsigned A) { Alignment = A; }
 216
 217   /// ensureAlignment - Make sure the function is at least 1 << A bytes aligned.
 218   void ensureAlignment(unsigned A) {
 219     if (Alignment < A) Alignment = A;
 220   }
 221
 222   /// exposesReturnsTwice - Returns true if the function calls setjmp or
 223   /// any other similar functions with attribute "returns twice" without
 224   /// having the attribute itself.
 225   bool exposesReturnsTwice() const {
 226     return ExposesReturnsTwice;
 227   }
 228
 229   /// setCallsSetJmp - Set a flag that indicates if there's a call to
 230   /// a "returns twice" function.
 231   void setExposesReturnsTwice(bool B) {
 232     ExposesReturnsTwice = B;
 233   }
 234
 235   /// Returns true if the function contains any inline assembly.
 236   bool hasInlineAsm() const {
 237     return HasInlineAsm;
 238   }
 239
 240   /// Set a flag that indicates that the function contains inline assembly.
 241   void setHasInlineAsm(bool B) {
 242     HasInlineAsm = B;
 243   }
 244
 245   /// getInfo - Keep track of various per-function pieces of information for
 246   /// backends that would like to do so.
 247   ///
 248   template<typename Ty>
 249   Ty *getInfo() {
 250     if (!MFInfo)
 251       MFInfo = Ty::template create<Ty>(Allocator, *this);
 252     return static_cast<Ty*>(MFInfo);
 253   }
 254
 255   template<typename Ty>
 256   const Ty *getInfo() const {
 257      return const_cast<MachineFunction*>(this)->getInfo<Ty>();
 258   }
 259
 260   /// getBlockNumbered - MachineBasicBlocks are automatically numbered when they
 261   /// are inserted into the machine function.  The block number for a machine
 262   /// basic block can be found by using the MBB::getBlockNumber method, this
 263   /// method provides the inverse mapping.
 264   ///
 265   MachineBasicBlock *getBlockNumbered(unsigned N) const {
 266     assert(N < MBBNumbering.size() && "Illegal block number");
 267     assert(MBBNumbering[N] && "Block was removed from the machine function!");
 268     return MBBNumbering[N];
 269   }
 270
 271   /// Should we be emitting segmented stack stuff for the function
 272   bool shouldSplitStack();
 273
 274   /// getNumBlockIDs - Return the number of MBB ID's allocated.
 275   ///
 276   unsigned getNumBlockIDs() const { return (unsigned)MBBNumbering.size(); }
 277
 278   /// RenumberBlocks - This discards all of the MachineBasicBlock numbers and
 279   /// recomputes them.  This guarantees that the MBB numbers are sequential,
 280   /// dense, and match the ordering of the blocks within the function.  If a
 281   /// specific MachineBasicBlock is specified, only that block and those after
 282   /// it are renumbered.
 283   void RenumberBlocks(MachineBasicBlock *MBBFrom = nullptr);
 284
 285   /// print - Print out the MachineFunction in a format suitable for debugging
 286   /// to the specified stream.
 287   ///
 288   void print(raw_ostream &OS, SlotIndexes* = nullptr) const;
 289
 290   /// viewCFG - This function is meant for use from the debugger.  You can just
 291   /// say 'call F->viewCFG()' and a ghostview window should pop up from the
 292   /// program, displaying the CFG of the current function with the code for each
 293   /// basic block inside.  This depends on there being a 'dot' and 'gv' program
 294   /// in your path.
 295   ///
 296   void viewCFG() const;
 297
 298   /// viewCFGOnly - This function is meant for use from the debugger.  It works
 299   /// just like viewCFG, but it does not include the contents of basic blocks
 300   /// into the nodes, just the label.  If you are only interested in the CFG
 301   /// this can make the graph smaller.
 302   ///
 303   void viewCFGOnly() const;
 304
 305   /// dump - Print the current MachineFunction to cerr, useful for debugger use.
 306   ///
 307   void dump() const;
 308
 309   /// verify - Run the current MachineFunction through the machine code
 310   /// verifier, useful for debugger use.
 311   void verify(Pass *p = nullptr, const char *Banner = nullptr) const;
 312
 313   // Provide accessors for the MachineBasicBlock list...
 314   typedef BasicBlockListType::iterator iterator;
 315   typedef BasicBlockListType::const_iterator const_iterator;
 316   typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
 317   typedef std::reverse_iterator<iterator>             reverse_iterator;
 318
 319   /// addLiveIn - Add the specified physical register as a live-in value and
 320   /// create a corresponding virtual register for it.
 321   unsigned addLiveIn(unsigned PReg, const TargetRegisterClass *RC);
 322
 323   //===--------------------------------------------------------------------===//
 324   // BasicBlock accessor functions.
 325   //
 326   iterator                 begin()       { return BasicBlocks.begin(); }
 327   const_iterator           begin() const { return BasicBlocks.begin(); }
 328   iterator                 end  ()       { return BasicBlocks.end();   }
 329   const_iterator           end  () const { return BasicBlocks.end();   }
 330
 331   reverse_iterator        rbegin()       { return BasicBlocks.rbegin(); }
 332   const_reverse_iterator  rbegin() const { return BasicBlocks.rbegin(); }
 333   reverse_iterator        rend  ()       { return BasicBlocks.rend();   }
 334   const_reverse_iterator  rend  () const { return BasicBlocks.rend();   }
 335
 336   unsigned                  size() const { return (unsigned)BasicBlocks.size();}
 337   bool                     empty() const { return BasicBlocks.empty(); }
 338   const MachineBasicBlock &front() const { return BasicBlocks.front(); }
 339         MachineBasicBlock &front()       { return BasicBlocks.front(); }
 340   const MachineBasicBlock & back() const { return BasicBlocks.back(); }
 341         MachineBasicBlock & back()       { return BasicBlocks.back(); }
 342
 343   void push_back (MachineBasicBlock *MBB) { BasicBlocks.push_back (MBB); }
 344   void push_front(MachineBasicBlock *MBB) { BasicBlocks.push_front(MBB); }
 345   void insert(iterator MBBI, MachineBasicBlock *MBB) {
 346     BasicBlocks.insert(MBBI, MBB);
 347   }
 348   void splice(iterator InsertPt, iterator MBBI) {
 349     BasicBlocks.splice(InsertPt, BasicBlocks, MBBI);
 350   }
 351   void splice(iterator InsertPt, iterator MBBI, iterator MBBE) {
 352     BasicBlocks.splice(InsertPt, BasicBlocks, MBBI, MBBE);
 353   }
 354
 355   void remove(iterator MBBI) {
 356     BasicBlocks.remove(MBBI);
 357   }
 358   void erase(iterator MBBI) {
 359     BasicBlocks.erase(MBBI);
 360   }
 361
 362   //===--------------------------------------------------------------------===//
 363   // Internal functions used to automatically number MachineBasicBlocks
 364   //
 365
 366   /// \brief Adds the MBB to the internal numbering. Returns the unique number
 367   /// assigned to the MBB.
 368   ///
 369   unsigned addToMBBNumbering(MachineBasicBlock *MBB) {
 370     MBBNumbering.push_back(MBB);
 371     return (unsigned)MBBNumbering.size()-1;
 372   }
 373
 374   /// removeFromMBBNumbering - Remove the specific machine basic block from our
 375   /// tracker, this is only really to be used by the MachineBasicBlock
 376   /// implementation.
 377   void removeFromMBBNumbering(unsigned N) {
 378     assert(N < MBBNumbering.size() && "Illegal basic block #");
 379     MBBNumbering[N] = nullptr;
 380   }
 381
 382   /// CreateMachineInstr - Allocate a new MachineInstr. Use this instead
 383   /// of `new MachineInstr'.
 384   ///
 385   MachineInstr *CreateMachineInstr(const MCInstrDesc &MCID,
 386                                    DebugLoc DL,
 387                                    bool NoImp = false);
 388
 389   /// CloneMachineInstr - Create a new MachineInstr which is a copy of the
 390   /// 'Orig' instruction, identical in all ways except the instruction
 391   /// has no parent, prev, or next.
 392   ///
 393   /// See also TargetInstrInfo::duplicate() for target-specific fixes to cloned
 394   /// instructions.
 395   MachineInstr *CloneMachineInstr(const MachineInstr *Orig);
 396
 397   /// DeleteMachineInstr - Delete the given MachineInstr.
 398   ///
 399   void DeleteMachineInstr(MachineInstr *MI);
 400
 401   /// CreateMachineBasicBlock - Allocate a new MachineBasicBlock. Use this
 402   /// instead of `new MachineBasicBlock'.
 403   ///
 404   MachineBasicBlock *CreateMachineBasicBlock(const BasicBlock *bb = nullptr);
 405
 406   /// DeleteMachineBasicBlock - Delete the given MachineBasicBlock.
 407   ///
 408   void DeleteMachineBasicBlock(MachineBasicBlock *MBB);
 409
 410   /// getMachineMemOperand - Allocate a new MachineMemOperand.
 411   /// MachineMemOperands are owned by the MachineFunction and need not be
 412   /// explicitly deallocated.
 413   MachineMemOperand *getMachineMemOperand(MachinePointerInfo PtrInfo,
 414                                           unsigned f, uint64_t s,
 415                                           unsigned base_alignment,
 416                                           const AAMDNodes &AAInfo = AAMDNodes(),
 417                                           const MDNode *Ranges = nullptr);
 418
 419   /// getMachineMemOperand - Allocate a new MachineMemOperand by copying
 420   /// an existing one, adjusting by an offset and using the given size.
 421   /// MachineMemOperands are owned by the MachineFunction and need not be
 422   /// explicitly deallocated.
 423   MachineMemOperand *getMachineMemOperand(const MachineMemOperand *MMO,
 424                                           int64_t Offset, uint64_t Size);
 425
 426   typedef ArrayRecycler<MachineOperand>::Capacity OperandCapacity;
 427
 428   /// Allocate an array of MachineOperands. This is only intended for use by
 429   /// internal MachineInstr functions.
 430   MachineOperand *allocateOperandArray(OperandCapacity Cap) {
 431     return OperandRecycler.allocate(Cap, Allocator);
 432   }
 433
 434   /// Dellocate an array of MachineOperands and recycle the memory. This is
 435   /// only intended for use by internal MachineInstr functions.
 436   /// Cap must be the same capacity that was used to allocate the array.
 437   void deallocateOperandArray(OperandCapacity Cap, MachineOperand *Array) {
 438     OperandRecycler.deallocate(Cap, Array);
 439   }
 440
 441   /// \brief Allocate and initialize a register mask with @p NumRegister bits.
 442   uint32_t *allocateRegisterMask(unsigned NumRegister) {
 443     unsigned Size = (NumRegister + 31) / 32;
 444     uint32_t *Mask = Allocator.Allocate<uint32_t>(Size);
 445     for (unsigned i = 0; i != Size; ++i)
 446       Mask[i] = 0;
 447     return Mask;
 448   }
 449
 450   /// allocateMemRefsArray - Allocate an array to hold MachineMemOperand
 451   /// pointers.  This array is owned by the MachineFunction.
 452   MachineInstr::mmo_iterator allocateMemRefsArray(unsigned long Num);
 453
 454   /// extractLoadMemRefs - Allocate an array and populate it with just the
 455   /// load information from the given MachineMemOperand sequence.
 456   std::pair<MachineInstr::mmo_iterator,
 457             MachineInstr::mmo_iterator>
 458     extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
 459                        MachineInstr::mmo_iterator End);
 460
 461   /// extractStoreMemRefs - Allocate an array and populate it with just the
 462   /// store information from the given MachineMemOperand sequence.
 463   std::pair<MachineInstr::mmo_iterator,
 464             MachineInstr::mmo_iterator>
 465     extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
 466                         MachineInstr::mmo_iterator End);
 467
 468   //===--------------------------------------------------------------------===//
 469   // Label Manipulation.
 470   //
 471
 472   /// getJTISymbol - Return the MCSymbol for the specified non-empty jump table.
 473   /// If isLinkerPrivate is specified, an 'l' label is returned, otherwise a
 474   /// normal 'L' label is returned.
 475   MCSymbol *getJTISymbol(unsigned JTI, MCContext &Ctx,
 476                          bool isLinkerPrivate = false) const;
 477
 478   /// getPICBaseSymbol - Return a function-local symbol to represent the PIC
 479   /// base.
 480   MCSymbol *getPICBaseSymbol() const;
 481 };
 482
 483 //===--------------------------------------------------------------------===//
 484 // GraphTraits specializations for function basic block graphs (CFGs)
 485 //===--------------------------------------------------------------------===//
 486
 487 // Provide specializations of GraphTraits to be able to treat a
 488 // machine function as a graph of machine basic blocks... these are
 489 // the same as the machine basic block iterators, except that the root
 490 // node is implicitly the first node of the function.
 491 //
 492 template <> struct GraphTraits<MachineFunction*> :
 493   public GraphTraits<MachineBasicBlock*> {
 494   static NodeType *getEntryNode(MachineFunction *F) {
 495     return &F->front();
 496   }
 497
 498   // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
 499   typedef MachineFunction::iterator nodes_iterator;
 500   static nodes_iterator nodes_begin(MachineFunction *F) { return F->begin(); }
 501   static nodes_iterator nodes_end  (MachineFunction *F) { return F->end(); }
 502   static unsigned       size       (MachineFunction *F) { return F->size(); }
 503 };
 504 template <> struct GraphTraits<const MachineFunction*> :
 505   public GraphTraits<const MachineBasicBlock*> {
 506   static NodeType *getEntryNode(const MachineFunction *F) {
 507     return &F->front();
 508   }
 509
 510   // nodes_iterator/begin/end - Allow iteration over all nodes in the graph
 511   typedef MachineFunction::const_iterator nodes_iterator;
 512   static nodes_iterator nodes_begin(const MachineFunction *F) {
 513     return F->begin();
 514   }
 515   static nodes_iterator nodes_end  (const MachineFunction *F) {
 516     return F->end();
 517   }
 518   static unsigned       size       (const MachineFunction *F)  {
 519     return F->size();
 520   }
 521 };
 522
 523
 524 // Provide specializations of GraphTraits to be able to treat a function as a
 525 // graph of basic blocks... and to walk it in inverse order.  Inverse order for
 526 // a function is considered to be when traversing the predecessor edges of a BB
 527 // instead of the successor edges.
 528 //
 529 template <> struct GraphTraits<Inverse<MachineFunction*> > :
 530   public GraphTraits<Inverse<MachineBasicBlock*> > {
 531   static NodeType *getEntryNode(Inverse<MachineFunction*> G) {
 532     return &G.Graph->front();
 533   }
 534 };
 535 template <> struct GraphTraits<Inverse<const MachineFunction*> > :
 536   public GraphTraits<Inverse<const MachineBasicBlock*> > {
 537   static NodeType *getEntryNode(Inverse<const MachineFunction *> G) {
 538     return &G.Graph->front();
 539   }
 540 };
 541
 542 } // End llvm namespace
 543
 544 #endif