1//===-- CodeGen/MachineFrameInfo.h - Abstract Stack Frame Rep. --*- 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// The file defines the MachineFrameInfo class. 11// 12//===----------------------------------------------------------------------===// 13 14#ifndef LLVM_CODEGEN_MACHINEFRAMEINFO_H 15#define LLVM_CODEGEN_MACHINEFRAMEINFO_H 16 17#include "llvm/ADT/SmallVector.h" 18#include "llvm/Support/DataTypes.h" 19#include <cassert> 20#include <vector> 21 22namespace llvm { 23class raw_ostream; 24class MachineFunction; 25class MachineBasicBlock; 26class BitVector; 27class AllocaInst; 28 29/// The CalleeSavedInfo class tracks the information need to locate where a 30/// callee saved register is in the current frame. 31class CalleeSavedInfo { 32 unsigned Reg; 33 int FrameIdx; 34 /// Flag indicating whether the register is actually restored in the epilog. 35 /// In most cases, if a register is saved, it is also restored. There are 36 /// some situations, though, when this is not the case. For example, the 37 /// LR register on ARM is usually saved, but on exit from the function its 38 /// saved value may be loaded directly into PC. Since liveness tracking of 39 /// physical registers treats callee-saved registers are live outside of 40 /// the function, LR would be treated as live-on-exit, even though in these 41 /// scenarios it is not. This flag is added to indicate that the saved 42 /// register described by this object is not restored in the epilog. 43 /// The long-term solution is to model the liveness of callee-saved registers 44 /// by implicit uses on the return instructions, however, the required 45 /// changes in the ARM backend would be quite extensive. 46 bool Restored; 47 48public: 49 explicit CalleeSavedInfo(unsigned R, int FI = 0) 50 : Reg(R), FrameIdx(FI), Restored(true) {} 51 52 // Accessors. 53 unsigned getReg() const { return Reg; } 54 int getFrameIdx() const { return FrameIdx; } 55 void setFrameIdx(int FI) { FrameIdx = FI; } 56 bool isRestored() const { return Restored; } 57 void setRestored(bool R) { Restored = R; } 58}; 59 60/// The MachineFrameInfo class represents an abstract stack frame until 61/// prolog/epilog code is inserted. This class is key to allowing stack frame 62/// representation optimizations, such as frame pointer elimination. It also 63/// allows more mundane (but still important) optimizations, such as reordering 64/// of abstract objects on the stack frame. 65/// 66/// To support this, the class assigns unique integer identifiers to stack 67/// objects requested clients. These identifiers are negative integers for 68/// fixed stack objects (such as arguments passed on the stack) or nonnegative 69/// for objects that may be reordered. Instructions which refer to stack 70/// objects use a special MO_FrameIndex operand to represent these frame 71/// indexes. 72/// 73/// Because this class keeps track of all references to the stack frame, it 74/// knows when a variable sized object is allocated on the stack. This is the 75/// sole condition which prevents frame pointer elimination, which is an 76/// important optimization on register-poor architectures. Because original 77/// variable sized alloca's in the source program are the only source of 78/// variable sized stack objects, it is safe to decide whether there will be 79/// any variable sized objects before all stack objects are known (for 80/// example, register allocator spill code never needs variable sized 81/// objects). 82/// 83/// When prolog/epilog code emission is performed, the final stack frame is 84/// built and the machine instructions are modified to refer to the actual 85/// stack offsets of the object, eliminating all MO_FrameIndex operands from 86/// the program. 87/// 88/// @brief Abstract Stack Frame Information 89class MachineFrameInfo { 90 91 // Represent a single object allocated on the stack. 92 struct StackObject { 93 // The offset of this object from the stack pointer on entry to 94 // the function. This field has no meaning for a variable sized element. 95 int64_t SPOffset; 96 97 // The size of this object on the stack. 0 means a variable sized object, 98 // ~0ULL means a dead object. 99 uint64_t Size; 100 101 // The required alignment of this stack slot. 102 unsigned Alignment; 103 104 // If true, the value of the stack object is set before 105 // entering the function and is not modified inside the function. By 106 // default, fixed objects are immutable unless marked otherwise. 107 bool isImmutable; 108 109 // If true the stack object is used as spill slot. It 110 // cannot alias any other memory objects. 111 bool isSpillSlot; 112 113 /// If true, this stack slot is used to spill a value (could be deopt 114 /// and/or GC related) over a statepoint. We know that the address of the 115 /// slot can't alias any LLVM IR value. This is very similar to a Spill 116 /// Slot, but is created by statepoint lowering is SelectionDAG, not the 117 /// register allocator. 118 bool isStatepointSpillSlot; 119 120 /// Identifier for stack memory type analagous to address space. If this is 121 /// non-0, the meaning is target defined. Offsets cannot be directly 122 /// compared between objects with different stack IDs. The object may not 123 /// necessarily reside in the same contiguous memory block as other stack 124 /// objects. Objects with differing stack IDs should not be merged or 125 /// replaced substituted for each other. 126 uint8_t StackID; 127 128 /// If this stack object is originated from an Alloca instruction 129 /// this value saves the original IR allocation. Can be NULL. 130 const AllocaInst *Alloca; 131 132 // If true, the object was mapped into the local frame 133 // block and doesn't need additional handling for allocation beyond that. 134 bool PreAllocated; 135 136 // If true, an LLVM IR value might point to this object. 137 // Normally, spill slots and fixed-offset objects don't alias IR-accessible 138 // objects, but there are exceptions (on PowerPC, for example, some byval 139 // arguments have ABI-prescribed offsets). 140 bool isAliased; 141 142 /// If true, the object has been zero-extended. 143 bool isZExt; 144 145 /// If true, the object has been zero-extended. 146 bool isSExt; 147 148 StackObject(uint64_t Sz, unsigned Al, int64_t SP, bool IM, 149 bool isSS, const AllocaInst *Val, bool Aliased, uint8_t ID = 0) 150 : SPOffset(SP), Size(Sz), Alignment(Al), isImmutable(IM), 151 isSpillSlot(isSS), isStatepointSpillSlot(false), StackID(ID), 152 Alloca(Val), 153 PreAllocated(false), isAliased(Aliased), isZExt(false), isSExt(false) {} 154 }; 155 156 /// The alignment of the stack. 157 unsigned StackAlignment; 158 159 /// Can the stack be realigned. This can be false if the target does not 160 /// support stack realignment, or if the user asks us not to realign the 161 /// stack. In this situation, overaligned allocas are all treated as dynamic 162 /// allocations and the target must handle them as part of DYNAMIC_STACKALLOC 163 /// lowering. All non-alloca stack objects have their alignment clamped to the 164 /// base ABI stack alignment. 165 /// FIXME: There is room for improvement in this case, in terms of 166 /// grouping overaligned allocas into a "secondary stack frame" and 167 /// then only use a single alloca to allocate this frame and only a 168 /// single virtual register to access it. Currently, without such an 169 /// optimization, each such alloca gets its own dynamic realignment. 170 bool StackRealignable; 171 172 /// Whether the function has the \c alignstack attribute. 173 bool ForcedRealign; 174 175 /// The list of stack objects allocated. 176 std::vector<StackObject> Objects; 177 178 /// This contains the number of fixed objects contained on 179 /// the stack. Because fixed objects are stored at a negative index in the 180 /// Objects list, this is also the index to the 0th object in the list. 181 unsigned NumFixedObjects = 0; 182 183 /// This boolean keeps track of whether any variable 184 /// sized objects have been allocated yet. 185 bool HasVarSizedObjects = false; 186 187 /// This boolean keeps track of whether there is a call 188 /// to builtin \@llvm.frameaddress. 189 bool FrameAddressTaken = false; 190 191 /// This boolean keeps track of whether there is a call 192 /// to builtin \@llvm.returnaddress. 193 bool ReturnAddressTaken = false; 194 195 /// This boolean keeps track of whether there is a call 196 /// to builtin \@llvm.experimental.stackmap. 197 bool HasStackMap = false; 198 199 /// This boolean keeps track of whether there is a call 200 /// to builtin \@llvm.experimental.patchpoint. 201 bool HasPatchPoint = false; 202 203 /// The prolog/epilog code inserter calculates the final stack 204 /// offsets for all of the fixed size objects, updating the Objects list 205 /// above. It then updates StackSize to contain the number of bytes that need 206 /// to be allocated on entry to the function. 207 uint64_t StackSize = 0; 208 209 /// The amount that a frame offset needs to be adjusted to 210 /// have the actual offset from the stack/frame pointer. The exact usage of 211 /// this is target-dependent, but it is typically used to adjust between 212 /// SP-relative and FP-relative offsets. E.G., if objects are accessed via 213 /// SP then OffsetAdjustment is zero; if FP is used, OffsetAdjustment is set 214 /// to the distance between the initial SP and the value in FP. For many 215 /// targets, this value is only used when generating debug info (via 216 /// TargetRegisterInfo::getFrameIndexReference); when generating code, the 217 /// corresponding adjustments are performed directly. 218 int OffsetAdjustment = 0; 219 220 /// The prolog/epilog code inserter may process objects that require greater 221 /// alignment than the default alignment the target provides. 222 /// To handle this, MaxAlignment is set to the maximum alignment 223 /// needed by the objects on the current frame. If this is greater than the 224 /// native alignment maintained by the compiler, dynamic alignment code will 225 /// be needed. 226 /// 227 unsigned MaxAlignment = 0; 228 229 /// Set to true if this function adjusts the stack -- e.g., 230 /// when calling another function. This is only valid during and after 231 /// prolog/epilog code insertion. 232 bool AdjustsStack = false; 233 234 /// Set to true if this function has any function calls. 235 bool HasCalls = false; 236 237 /// The frame index for the stack protector. 238 int StackProtectorIdx = -1; 239 240 /// The frame index for the function context. Used for SjLj exceptions. 241 int FunctionContextIdx = -1; 242 243 /// This contains the size of the largest call frame if the target uses frame 244 /// setup/destroy pseudo instructions (as defined in the TargetFrameInfo 245 /// class). This information is important for frame pointer elimination. 246 /// It is only valid during and after prolog/epilog code insertion. 247 unsigned MaxCallFrameSize = ~0u; 248 249 /// The prolog/epilog code inserter fills in this vector with each 250 /// callee saved register saved in the frame. Beyond its use by the prolog/ 251 /// epilog code inserter, this data used for debug info and exception 252 /// handling. 253 std::vector<CalleeSavedInfo> CSInfo; 254 255 /// Has CSInfo been set yet? 256 bool CSIValid = false; 257 258 /// References to frame indices which are mapped 259 /// into the local frame allocation block. <FrameIdx, LocalOffset> 260 SmallVector<std::pair<int, int64_t>, 32> LocalFrameObjects; 261 262 /// Size of the pre-allocated local frame block. 263 int64_t LocalFrameSize = 0; 264 265 /// Required alignment of the local object blob, which is the strictest 266 /// alignment of any object in it. 267 unsigned LocalFrameMaxAlign = 0; 268 269 /// Whether the local object blob needs to be allocated together. If not, 270 /// PEI should ignore the isPreAllocated flags on the stack objects and 271 /// just allocate them normally. 272 bool UseLocalStackAllocationBlock = false; 273 274 /// True if the function dynamically adjusts the stack pointer through some 275 /// opaque mechanism like inline assembly or Win32 EH. 276 bool HasOpaqueSPAdjustment = false; 277 278 /// True if the function contains operations which will lower down to 279 /// instructions which manipulate the stack pointer. 280 bool HasCopyImplyingStackAdjustment = false; 281 282 /// True if the function contains a call to the llvm.vastart intrinsic. 283 bool HasVAStart = false; 284 285 /// True if this is a varargs function that contains a musttail call. 286 bool HasMustTailInVarArgFunc = false; 287 288 /// True if this function contains a tail call. If so immutable objects like 289 /// function arguments are no longer so. A tail call *can* override fixed 290 /// stack objects like arguments so we can't treat them as immutable. 291 bool HasTailCall = false; 292 293 /// Not null, if shrink-wrapping found a better place for the prologue. 294 MachineBasicBlock *Save = nullptr; 295 /// Not null, if shrink-wrapping found a better place for the epilogue. 296 MachineBasicBlock *Restore = nullptr; 297 298public: 299 explicit MachineFrameInfo(unsigned StackAlignment, bool StackRealignable, 300 bool ForcedRealign) 301 : StackAlignment(StackAlignment), StackRealignable(StackRealignable), 302 ForcedRealign(ForcedRealign) {} 303 304 /// Return true if there are any stack objects in this function. 305 bool hasStackObjects() const { return !Objects.empty(); } 306 307 /// This method may be called any time after instruction 308 /// selection is complete to determine if the stack frame for this function 309 /// contains any variable sized objects. 310 bool hasVarSizedObjects() const { return HasVarSizedObjects; } 311 312 /// Return the index for the stack protector object. 313 int getStackProtectorIndex() const { return StackProtectorIdx; } 314 void setStackProtectorIndex(int I) { StackProtectorIdx = I; } 315 bool hasStackProtectorIndex() const { return StackProtectorIdx != -1; } 316 317 /// Return the index for the function context object. 318 /// This object is used for SjLj exceptions. 319 int getFunctionContextIndex() const { return FunctionContextIdx; } 320 void setFunctionContextIndex(int I) { FunctionContextIdx = I; } 321 322 /// This method may be called any time after instruction 323 /// selection is complete to determine if there is a call to 324 /// \@llvm.frameaddress in this function. 325 bool isFrameAddressTaken() const { return FrameAddressTaken; } 326 void setFrameAddressIsTaken(bool T) { FrameAddressTaken = T; } 327 328 /// This method may be called any time after 329 /// instruction selection is complete to determine if there is a call to 330 /// \@llvm.returnaddress in this function. 331 bool isReturnAddressTaken() const { return ReturnAddressTaken; } 332 void setReturnAddressIsTaken(bool s) { ReturnAddressTaken = s; } 333 334 /// This method may be called any time after instruction 335 /// selection is complete to determine if there is a call to builtin 336 /// \@llvm.experimental.stackmap. 337 bool hasStackMap() const { return HasStackMap; } 338 void setHasStackMap(bool s = true) { HasStackMap = s; } 339 340 /// This method may be called any time after instruction 341 /// selection is complete to determine if there is a call to builtin 342 /// \@llvm.experimental.patchpoint. 343 bool hasPatchPoint() const { return HasPatchPoint; } 344 void setHasPatchPoint(bool s = true) { HasPatchPoint = s; } 345 346 /// Return the minimum frame object index. 347 int getObjectIndexBegin() const { return -NumFixedObjects; } 348 349 /// Return one past the maximum frame object index. 350 int getObjectIndexEnd() const { return (int)Objects.size()-NumFixedObjects; } 351 352 /// Return the number of fixed objects. 353 unsigned getNumFixedObjects() const { return NumFixedObjects; } 354 355 /// Return the number of objects. 356 unsigned getNumObjects() const { return Objects.size(); } 357 358 /// Map a frame index into the local object block 359 void mapLocalFrameObject(int ObjectIndex, int64_t Offset) { 360 LocalFrameObjects.push_back(std::pair<int, int64_t>(ObjectIndex, Offset)); 361 Objects[ObjectIndex + NumFixedObjects].PreAllocated = true; 362 } 363 364 /// Get the local offset mapping for a for an object. 365 std::pair<int, int64_t> getLocalFrameObjectMap(int i) const { 366 assert (i >= 0 && (unsigned)i < LocalFrameObjects.size() && 367 "Invalid local object reference!"); 368 return LocalFrameObjects[i]; 369 } 370 371 /// Return the number of objects allocated into the local object block. 372 int64_t getLocalFrameObjectCount() const { return LocalFrameObjects.size(); } 373 374 /// Set the size of the local object blob. 375 void setLocalFrameSize(int64_t sz) { LocalFrameSize = sz; } 376 377 /// Get the size of the local object blob. 378 int64_t getLocalFrameSize() const { return LocalFrameSize; } 379 380 /// Required alignment of the local object blob, 381 /// which is the strictest alignment of any object in it. 382 void setLocalFrameMaxAlign(unsigned Align) { LocalFrameMaxAlign = Align; } 383 384 /// Return the required alignment of the local object blob. 385 unsigned getLocalFrameMaxAlign() const { return LocalFrameMaxAlign; } 386 387 /// Get whether the local allocation blob should be allocated together or 388 /// let PEI allocate the locals in it directly. 389 bool getUseLocalStackAllocationBlock() const { 390 return UseLocalStackAllocationBlock; 391 } 392 393 /// setUseLocalStackAllocationBlock - Set whether the local allocation blob 394 /// should be allocated together or let PEI allocate the locals in it 395 /// directly. 396 void setUseLocalStackAllocationBlock(bool v) { 397 UseLocalStackAllocationBlock = v; 398 } 399 400 /// Return true if the object was pre-allocated into the local block. 401 bool isObjectPreAllocated(int ObjectIdx) const { 402 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 403 "Invalid Object Idx!"); 404 return Objects[ObjectIdx+NumFixedObjects].PreAllocated; 405 } 406 407 /// Return the size of the specified object. 408 int64_t getObjectSize(int ObjectIdx) const { 409 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 410 "Invalid Object Idx!"); 411 return Objects[ObjectIdx+NumFixedObjects].Size; 412 } 413 414 /// Change the size of the specified stack object. 415 void setObjectSize(int ObjectIdx, int64_t Size) { 416 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 417 "Invalid Object Idx!"); 418 Objects[ObjectIdx+NumFixedObjects].Size = Size; 419 } 420 421 /// Return the alignment of the specified stack object. 422 unsigned getObjectAlignment(int ObjectIdx) const { 423 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 424 "Invalid Object Idx!"); 425 return Objects[ObjectIdx+NumFixedObjects].Alignment; 426 } 427 428 /// setObjectAlignment - Change the alignment of the specified stack object. 429 void setObjectAlignment(int ObjectIdx, unsigned Align) { 430 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 431 "Invalid Object Idx!"); 432 Objects[ObjectIdx+NumFixedObjects].Alignment = Align; 433 ensureMaxAlignment(Align); 434 } 435 436 /// Return the underlying Alloca of the specified 437 /// stack object if it exists. Returns 0 if none exists. 438 const AllocaInst* getObjectAllocation(int ObjectIdx) const { 439 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 440 "Invalid Object Idx!"); 441 return Objects[ObjectIdx+NumFixedObjects].Alloca; 442 } 443 444 /// Return the assigned stack offset of the specified object 445 /// from the incoming stack pointer. 446 int64_t getObjectOffset(int ObjectIdx) const { 447 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 448 "Invalid Object Idx!"); 449 assert(!isDeadObjectIndex(ObjectIdx) && 450 "Getting frame offset for a dead object?"); 451 return Objects[ObjectIdx+NumFixedObjects].SPOffset; 452 } 453 454 bool isObjectZExt(int ObjectIdx) const { 455 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 456 "Invalid Object Idx!"); 457 return Objects[ObjectIdx+NumFixedObjects].isZExt; 458 } 459 460 void setObjectZExt(int ObjectIdx, bool IsZExt) { 461 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 462 "Invalid Object Idx!"); 463 Objects[ObjectIdx+NumFixedObjects].isZExt = IsZExt; 464 } 465 466 bool isObjectSExt(int ObjectIdx) const { 467 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 468 "Invalid Object Idx!"); 469 return Objects[ObjectIdx+NumFixedObjects].isSExt; 470 } 471 472 void setObjectSExt(int ObjectIdx, bool IsSExt) { 473 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 474 "Invalid Object Idx!"); 475 Objects[ObjectIdx+NumFixedObjects].isSExt = IsSExt; 476 } 477 478 /// Set the stack frame offset of the specified object. The 479 /// offset is relative to the stack pointer on entry to the function. 480 void setObjectOffset(int ObjectIdx, int64_t SPOffset) { 481 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 482 "Invalid Object Idx!"); 483 assert(!isDeadObjectIndex(ObjectIdx) && 484 "Setting frame offset for a dead object?"); 485 Objects[ObjectIdx+NumFixedObjects].SPOffset = SPOffset; 486 } 487 488 /// Return the number of bytes that must be allocated to hold 489 /// all of the fixed size frame objects. This is only valid after 490 /// Prolog/Epilog code insertion has finalized the stack frame layout. 491 uint64_t getStackSize() const { return StackSize; } 492 493 /// Set the size of the stack. 494 void setStackSize(uint64_t Size) { StackSize = Size; } 495 496 /// Estimate and return the size of the stack frame. 497 unsigned estimateStackSize(const MachineFunction &MF) const; 498 499 /// Return the correction for frame offsets. 500 int getOffsetAdjustment() const { return OffsetAdjustment; } 501 502 /// Set the correction for frame offsets. 503 void setOffsetAdjustment(int Adj) { OffsetAdjustment = Adj; } 504 505 /// Return the alignment in bytes that this function must be aligned to, 506 /// which is greater than the default stack alignment provided by the target. 507 unsigned getMaxAlignment() const { return MaxAlignment; } 508 509 /// Make sure the function is at least Align bytes aligned. 510 void ensureMaxAlignment(unsigned Align); 511 512 /// Return true if this function adjusts the stack -- e.g., 513 /// when calling another function. This is only valid during and after 514 /// prolog/epilog code insertion. 515 bool adjustsStack() const { return AdjustsStack; } 516 void setAdjustsStack(bool V) { AdjustsStack = V; } 517 518 /// Return true if the current function has any function calls. 519 bool hasCalls() const { return HasCalls; } 520 void setHasCalls(bool V) { HasCalls = V; } 521 522 /// Returns true if the function contains opaque dynamic stack adjustments. 523 bool hasOpaqueSPAdjustment() const { return HasOpaqueSPAdjustment; } 524 void setHasOpaqueSPAdjustment(bool B) { HasOpaqueSPAdjustment = B; } 525 526 /// Returns true if the function contains operations which will lower down to 527 /// instructions which manipulate the stack pointer. 528 bool hasCopyImplyingStackAdjustment() const { 529 return HasCopyImplyingStackAdjustment; 530 } 531 void setHasCopyImplyingStackAdjustment(bool B) { 532 HasCopyImplyingStackAdjustment = B; 533 } 534 535 /// Returns true if the function calls the llvm.va_start intrinsic. 536 bool hasVAStart() const { return HasVAStart; } 537 void setHasVAStart(bool B) { HasVAStart = B; } 538 539 /// Returns true if the function is variadic and contains a musttail call. 540 bool hasMustTailInVarArgFunc() const { return HasMustTailInVarArgFunc; } 541 void setHasMustTailInVarArgFunc(bool B) { HasMustTailInVarArgFunc = B; } 542 543 /// Returns true if the function contains a tail call. 544 bool hasTailCall() const { return HasTailCall; } 545 void setHasTailCall() { HasTailCall = true; } 546 547 /// Computes the maximum size of a callframe and the AdjustsStack property. 548 /// This only works for targets defining 549 /// TargetInstrInfo::getCallFrameSetupOpcode(), getCallFrameDestroyOpcode(), 550 /// and getFrameSize(). 551 /// This is usually computed by the prologue epilogue inserter but some 552 /// targets may call this to compute it earlier. 553 void computeMaxCallFrameSize(const MachineFunction &MF); 554 555 /// Return the maximum size of a call frame that must be 556 /// allocated for an outgoing function call. This is only available if 557 /// CallFrameSetup/Destroy pseudo instructions are used by the target, and 558 /// then only during or after prolog/epilog code insertion. 559 /// 560 unsigned getMaxCallFrameSize() const { 561 // TODO: Enable this assert when targets are fixed. 562 //assert(isMaxCallFrameSizeComputed() && "MaxCallFrameSize not computed yet"); 563 if (!isMaxCallFrameSizeComputed()) 564 return 0; 565 return MaxCallFrameSize; 566 } 567 bool isMaxCallFrameSizeComputed() const { 568 return MaxCallFrameSize != ~0u; 569 } 570 void setMaxCallFrameSize(unsigned S) { MaxCallFrameSize = S; } 571 572 /// Create a new object at a fixed location on the stack. 573 /// All fixed objects should be created before other objects are created for 574 /// efficiency. By default, fixed objects are not pointed to by LLVM IR 575 /// values. This returns an index with a negative value. 576 int CreateFixedObject(uint64_t Size, int64_t SPOffset, bool Immutable, 577 bool isAliased = false); 578 579 /// Create a spill slot at a fixed location on the stack. 580 /// Returns an index with a negative value. 581 int CreateFixedSpillStackObject(uint64_t Size, int64_t SPOffset, 582 bool Immutable = false); 583 584 /// Returns true if the specified index corresponds to a fixed stack object. 585 bool isFixedObjectIndex(int ObjectIdx) const { 586 return ObjectIdx < 0 && (ObjectIdx >= -(int)NumFixedObjects); 587 } 588 589 /// Returns true if the specified index corresponds 590 /// to an object that might be pointed to by an LLVM IR value. 591 bool isAliasedObjectIndex(int ObjectIdx) const { 592 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 593 "Invalid Object Idx!"); 594 return Objects[ObjectIdx+NumFixedObjects].isAliased; 595 } 596 597 /// Returns true if the specified index corresponds to an immutable object. 598 bool isImmutableObjectIndex(int ObjectIdx) const { 599 // Tail calling functions can clobber their function arguments. 600 if (HasTailCall) 601 return false; 602 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 603 "Invalid Object Idx!"); 604 return Objects[ObjectIdx+NumFixedObjects].isImmutable; 605 } 606 607 /// Marks the immutability of an object. 608 void setIsImmutableObjectIndex(int ObjectIdx, bool Immutable) { 609 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 610 "Invalid Object Idx!"); 611 Objects[ObjectIdx+NumFixedObjects].isImmutable = Immutable; 612 } 613 614 /// Returns true if the specified index corresponds to a spill slot. 615 bool isSpillSlotObjectIndex(int ObjectIdx) const { 616 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 617 "Invalid Object Idx!"); 618 return Objects[ObjectIdx+NumFixedObjects].isSpillSlot; 619 } 620 621 bool isStatepointSpillSlotObjectIndex(int ObjectIdx) const { 622 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 623 "Invalid Object Idx!"); 624 return Objects[ObjectIdx+NumFixedObjects].isStatepointSpillSlot; 625 } 626 627 /// \see StackID 628 uint8_t getStackID(int ObjectIdx) const { 629 return Objects[ObjectIdx+NumFixedObjects].StackID; 630 } 631 632 /// \see StackID 633 void setStackID(int ObjectIdx, uint8_t ID) { 634 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 635 "Invalid Object Idx!"); 636 Objects[ObjectIdx+NumFixedObjects].StackID = ID; 637 } 638 639 /// Returns true if the specified index corresponds to a dead object. 640 bool isDeadObjectIndex(int ObjectIdx) const { 641 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 642 "Invalid Object Idx!"); 643 return Objects[ObjectIdx+NumFixedObjects].Size == ~0ULL; 644 } 645 646 /// Returns true if the specified index corresponds to a variable sized 647 /// object. 648 bool isVariableSizedObjectIndex(int ObjectIdx) const { 649 assert(unsigned(ObjectIdx + NumFixedObjects) < Objects.size() && 650 "Invalid Object Idx!"); 651 return Objects[ObjectIdx + NumFixedObjects].Size == 0; 652 } 653 654 void markAsStatepointSpillSlotObjectIndex(int ObjectIdx) { 655 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && 656 "Invalid Object Idx!"); 657 Objects[ObjectIdx+NumFixedObjects].isStatepointSpillSlot = true; 658 assert(isStatepointSpillSlotObjectIndex(ObjectIdx) && "inconsistent"); 659 } 660 661 /// Create a new statically sized stack object, returning 662 /// a nonnegative identifier to represent it. 663 int CreateStackObject(uint64_t Size, unsigned Alignment, bool isSS, 664 const AllocaInst *Alloca = nullptr, uint8_t ID = 0); 665 666 /// Create a new statically sized stack object that represents a spill slot, 667 /// returning a nonnegative identifier to represent it. 668 int CreateSpillStackObject(uint64_t Size, unsigned Alignment); 669 670 /// Remove or mark dead a statically sized stack object. 671 void RemoveStackObject(int ObjectIdx) { 672 // Mark it dead. 673 Objects[ObjectIdx+NumFixedObjects].Size = ~0ULL; 674 } 675 676 /// Notify the MachineFrameInfo object that a variable sized object has been 677 /// created. This must be created whenever a variable sized object is 678 /// created, whether or not the index returned is actually used. 679 int CreateVariableSizedObject(unsigned Alignment, const AllocaInst *Alloca); 680 681 /// Returns a reference to call saved info vector for the current function. 682 const std::vector<CalleeSavedInfo> &getCalleeSavedInfo() const { 683 return CSInfo; 684 } 685 /// \copydoc getCalleeSavedInfo() 686 std::vector<CalleeSavedInfo> &getCalleeSavedInfo() { return CSInfo; } 687 688 /// Used by prolog/epilog inserter to set the function's callee saved 689 /// information. 690 void setCalleeSavedInfo(const std::vector<CalleeSavedInfo> &CSI) { 691 CSInfo = CSI; 692 } 693 694 /// Has the callee saved info been calculated yet? 695 bool isCalleeSavedInfoValid() const { return CSIValid; } 696 697 void setCalleeSavedInfoValid(bool v) { CSIValid = v; } 698 699 MachineBasicBlock *getSavePoint() const { return Save; } 700 void setSavePoint(MachineBasicBlock *NewSave) { Save = NewSave; } 701 MachineBasicBlock *getRestorePoint() const { return Restore; } 702 void setRestorePoint(MachineBasicBlock *NewRestore) { Restore = NewRestore; } 703 704 /// Return a set of physical registers that are pristine. 705 /// 706 /// Pristine registers hold a value that is useless to the current function, 707 /// but that must be preserved - they are callee saved registers that are not 708 /// saved. 709 /// 710 /// Before the PrologueEpilogueInserter has placed the CSR spill code, this 711 /// method always returns an empty set. 712 BitVector getPristineRegs(const MachineFunction &MF) const; 713 714 /// Used by the MachineFunction printer to print information about 715 /// stack objects. Implemented in MachineFunction.cpp. 716 void print(const MachineFunction &MF, raw_ostream &OS) const; 717 718 /// dump - Print the function to stderr. 719 void dump(const MachineFunction &MF) const; 720}; 721 722} // End llvm namespace 723 724#endif 725