1 //===-- CodeGen/MachineFrameInfo.h - Abstract Stack Frame Rep. --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // The file defines the MachineFrameInfo class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CODEGEN_MACHINEFRAMEINFO_H
15 #define LLVM_CODEGEN_MACHINEFRAMEINFO_H
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/Support/DataTypes.h"
25 class TargetRegisterClass;
27 class MachineFunction;
28 class MachineBasicBlock;
29 class TargetFrameLowering;
35 /// The CalleeSavedInfo class tracks the information need to locate where a
36 /// callee saved register is in the current frame.
37 class CalleeSavedInfo {
42 explicit CalleeSavedInfo(unsigned R, int FI = 0)
43 : Reg(R), FrameIdx(FI) {}
46 unsigned getReg() const { return Reg; }
47 int getFrameIdx() const { return FrameIdx; }
48 void setFrameIdx(int FI) { FrameIdx = FI; }
51 /// The MachineFrameInfo class represents an abstract stack frame until
52 /// prolog/epilog code is inserted. This class is key to allowing stack frame
53 /// representation optimizations, such as frame pointer elimination. It also
54 /// allows more mundane (but still important) optimizations, such as reordering
55 /// of abstract objects on the stack frame.
57 /// To support this, the class assigns unique integer identifiers to stack
58 /// objects requested clients. These identifiers are negative integers for
59 /// fixed stack objects (such as arguments passed on the stack) or nonnegative
60 /// for objects that may be reordered. Instructions which refer to stack
61 /// objects use a special MO_FrameIndex operand to represent these frame
64 /// Because this class keeps track of all references to the stack frame, it
65 /// knows when a variable sized object is allocated on the stack. This is the
66 /// sole condition which prevents frame pointer elimination, which is an
67 /// important optimization on register-poor architectures. Because original
68 /// variable sized alloca's in the source program are the only source of
69 /// variable sized stack objects, it is safe to decide whether there will be
70 /// any variable sized objects before all stack objects are known (for
71 /// example, register allocator spill code never needs variable sized
74 /// When prolog/epilog code emission is performed, the final stack frame is
75 /// built and the machine instructions are modified to refer to the actual
76 /// stack offsets of the object, eliminating all MO_FrameIndex operands from
79 /// @brief Abstract Stack Frame Information
80 class MachineFrameInfo {
82 // Represent a single object allocated on the stack.
84 // The offset of this object from the stack pointer on entry to
85 // the function. This field has no meaning for a variable sized element.
88 // The size of this object on the stack. 0 means a variable sized object,
89 // ~0ULL means a dead object.
92 // The required alignment of this stack slot.
95 // If true, the value of the stack object is set before
96 // entering the function and is not modified inside the function. By
97 // default, fixed objects are immutable unless marked otherwise.
100 // If true the stack object is used as spill slot. It
101 // cannot alias any other memory objects.
104 /// If true, this stack slot is used to spill a value (could be deopt
105 /// and/or GC related) over a statepoint. We know that the address of the
106 /// slot can't alias any LLVM IR value. This is very similiar to a Spill
107 /// Slot, but is created by statepoint lowering is SelectionDAG, not the
108 /// register allocator.
109 bool isStatepointSpillSlot;
111 /// If this stack object is originated from an Alloca instruction
112 /// this value saves the original IR allocation. Can be NULL.
113 const AllocaInst *Alloca;
115 // If true, the object was mapped into the local frame
116 // block and doesn't need additional handling for allocation beyond that.
119 // If true, an LLVM IR value might point to this object.
120 // Normally, spill slots and fixed-offset objects don't alias IR-accessible
121 // objects, but there are exceptions (on PowerPC, for example, some byval
122 // arguments have ABI-prescribed offsets).
125 StackObject(uint64_t Sz, unsigned Al, int64_t SP, bool IM,
126 bool isSS, const AllocaInst *Val, bool A)
127 : SPOffset(SP), Size(Sz), Alignment(Al), isImmutable(IM),
128 isSpillSlot(isSS), isStatepointSpillSlot(false), Alloca(Val),
129 PreAllocated(false), isAliased(A) {}
132 /// The alignment of the stack.
133 unsigned StackAlignment;
135 /// Can the stack be realigned.
136 /// Targets that set this to false don't have the ability to overalign
137 /// their stack frame, and thus, overaligned allocas are all treated
138 /// as dynamic allocations and the target must handle them as part
139 /// of DYNAMIC_STACKALLOC lowering.
140 /// FIXME: There is room for improvement in this case, in terms of
141 /// grouping overaligned allocas into a "secondary stack frame" and
142 /// then only use a single alloca to allocate this frame and only a
143 /// single virtual register to access it. Currently, without such an
144 /// optimization, each such alloca gets it's own dynamic
146 bool StackRealignable;
148 /// The list of stack objects allocated.
149 std::vector<StackObject> Objects;
151 /// This contains the number of fixed objects contained on
152 /// the stack. Because fixed objects are stored at a negative index in the
153 /// Objects list, this is also the index to the 0th object in the list.
154 unsigned NumFixedObjects;
156 /// This boolean keeps track of whether any variable
157 /// sized objects have been allocated yet.
158 bool HasVarSizedObjects;
160 /// This boolean keeps track of whether there is a call
161 /// to builtin \@llvm.frameaddress.
162 bool FrameAddressTaken;
164 /// This boolean keeps track of whether there is a call
165 /// to builtin \@llvm.returnaddress.
166 bool ReturnAddressTaken;
168 /// This boolean keeps track of whether there is a call
169 /// to builtin \@llvm.experimental.stackmap.
172 /// This boolean keeps track of whether there is a call
173 /// to builtin \@llvm.experimental.patchpoint.
176 /// The prolog/epilog code inserter calculates the final stack
177 /// offsets for all of the fixed size objects, updating the Objects list
178 /// above. It then updates StackSize to contain the number of bytes that need
179 /// to be allocated on entry to the function.
182 /// The amount that a frame offset needs to be adjusted to
183 /// have the actual offset from the stack/frame pointer. The exact usage of
184 /// this is target-dependent, but it is typically used to adjust between
185 /// SP-relative and FP-relative offsets. E.G., if objects are accessed via
186 /// SP then OffsetAdjustment is zero; if FP is used, OffsetAdjustment is set
187 /// to the distance between the initial SP and the value in FP. For many
188 /// targets, this value is only used when generating debug info (via
189 /// TargetRegisterInfo::getFrameIndexReference); when generating code, the
190 /// corresponding adjustments are performed directly.
191 int OffsetAdjustment;
193 /// The prolog/epilog code inserter may process objects that require greater
194 /// alignment than the default alignment the target provides.
195 /// To handle this, MaxAlignment is set to the maximum alignment
196 /// needed by the objects on the current frame. If this is greater than the
197 /// native alignment maintained by the compiler, dynamic alignment code will
200 unsigned MaxAlignment;
202 /// Set to true if this function adjusts the stack -- e.g.,
203 /// when calling another function. This is only valid during and after
204 /// prolog/epilog code insertion.
207 /// Set to true if this function has any function calls.
210 /// The frame index for the stack protector.
211 int StackProtectorIdx;
213 /// The frame index for the function context. Used for SjLj exceptions.
214 int FunctionContextIdx;
216 /// This contains the size of the largest call frame if the target uses frame
217 /// setup/destroy pseudo instructions (as defined in the TargetFrameInfo
218 /// class). This information is important for frame pointer elimination.
219 /// It is only valid during and after prolog/epilog code insertion.
220 unsigned MaxCallFrameSize;
222 /// The prolog/epilog code inserter fills in this vector with each
223 /// callee saved register saved in the frame. Beyond its use by the prolog/
224 /// epilog code inserter, this data used for debug info and exception
226 std::vector<CalleeSavedInfo> CSInfo;
228 /// Has CSInfo been set yet?
231 /// References to frame indices which are mapped
232 /// into the local frame allocation block. <FrameIdx, LocalOffset>
233 SmallVector<std::pair<int, int64_t>, 32> LocalFrameObjects;
235 /// Size of the pre-allocated local frame block.
236 int64_t LocalFrameSize;
238 /// Required alignment of the local object blob, which is the strictest
239 /// alignment of any object in it.
240 unsigned LocalFrameMaxAlign;
242 /// Whether the local object blob needs to be allocated together. If not,
243 /// PEI should ignore the isPreAllocated flags on the stack objects and
244 /// just allocate them normally.
245 bool UseLocalStackAllocationBlock;
247 /// Whether the "realign-stack" option is on.
250 /// True if the function dynamically adjusts the stack pointer through some
251 /// opaque mechanism like inline assembly or Win32 EH.
252 bool HasOpaqueSPAdjustment;
254 /// True if the function contains a call to the llvm.vastart intrinsic.
257 /// True if this is a varargs function that contains a musttail call.
258 bool HasMustTailInVarArgFunc;
260 /// True if this function contains a tail call. If so immutable objects like
261 /// function arguments are no longer so. A tail call *can* override fixed
262 /// stack objects like arguments so we can't treat them as immutable.
265 /// Not null, if shrink-wrapping found a better place for the prologue.
266 MachineBasicBlock *Save;
267 /// Not null, if shrink-wrapping found a better place for the epilogue.
268 MachineBasicBlock *Restore;
271 explicit MachineFrameInfo(unsigned StackAlign, bool isStackRealign,
273 : StackAlignment(StackAlign), StackRealignable(isStackRealign),
274 RealignOption(RealignOpt) {
275 StackSize = NumFixedObjects = OffsetAdjustment = MaxAlignment = 0;
276 HasVarSizedObjects = false;
277 FrameAddressTaken = false;
278 ReturnAddressTaken = false;
280 HasPatchPoint = false;
281 AdjustsStack = false;
283 StackProtectorIdx = -1;
284 FunctionContextIdx = -1;
285 MaxCallFrameSize = 0;
288 LocalFrameMaxAlign = 0;
289 UseLocalStackAllocationBlock = false;
290 HasOpaqueSPAdjustment = false;
292 HasMustTailInVarArgFunc = false;
298 /// Return true if there are any stack objects in this function.
299 bool hasStackObjects() const { return !Objects.empty(); }
301 /// This method may be called any time after instruction
302 /// selection is complete to determine if the stack frame for this function
303 /// contains any variable sized objects.
304 bool hasVarSizedObjects() const { return HasVarSizedObjects; }
306 /// Return the index for the stack protector object.
307 int getStackProtectorIndex() const { return StackProtectorIdx; }
308 void setStackProtectorIndex(int I) { StackProtectorIdx = I; }
309 bool hasStackProtectorIndex() const { return StackProtectorIdx != -1; }
311 /// Return the index for the function context object.
312 /// This object is used for SjLj exceptions.
313 int getFunctionContextIndex() const { return FunctionContextIdx; }
314 void setFunctionContextIndex(int I) { FunctionContextIdx = I; }
316 /// This method may be called any time after instruction
317 /// selection is complete to determine if there is a call to
318 /// \@llvm.frameaddress in this function.
319 bool isFrameAddressTaken() const { return FrameAddressTaken; }
320 void setFrameAddressIsTaken(bool T) { FrameAddressTaken = T; }
322 /// This method may be called any time after
323 /// instruction selection is complete to determine if there is a call to
324 /// \@llvm.returnaddress in this function.
325 bool isReturnAddressTaken() const { return ReturnAddressTaken; }
326 void setReturnAddressIsTaken(bool s) { ReturnAddressTaken = s; }
328 /// This method may be called any time after instruction
329 /// selection is complete to determine if there is a call to builtin
330 /// \@llvm.experimental.stackmap.
331 bool hasStackMap() const { return HasStackMap; }
332 void setHasStackMap(bool s = true) { HasStackMap = s; }
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.patchpoint.
337 bool hasPatchPoint() const { return HasPatchPoint; }
338 void setHasPatchPoint(bool s = true) { HasPatchPoint = s; }
340 /// Return the minimum frame object index.
341 int getObjectIndexBegin() const { return -NumFixedObjects; }
343 /// Return one past the maximum frame object index.
344 int getObjectIndexEnd() const { return (int)Objects.size()-NumFixedObjects; }
346 /// Return the number of fixed objects.
347 unsigned getNumFixedObjects() const { return NumFixedObjects; }
349 /// Return the number of objects.
350 unsigned getNumObjects() const { return Objects.size(); }
352 /// Map a frame index into the local object block
353 void mapLocalFrameObject(int ObjectIndex, int64_t Offset) {
354 LocalFrameObjects.push_back(std::pair<int, int64_t>(ObjectIndex, Offset));
355 Objects[ObjectIndex + NumFixedObjects].PreAllocated = true;
358 /// Get the local offset mapping for a for an object.
359 std::pair<int, int64_t> getLocalFrameObjectMap(int i) const {
360 assert (i >= 0 && (unsigned)i < LocalFrameObjects.size() &&
361 "Invalid local object reference!");
362 return LocalFrameObjects[i];
365 /// Return the number of objects allocated into the local object block.
366 int64_t getLocalFrameObjectCount() const { return LocalFrameObjects.size(); }
368 /// Set the size of the local object blob.
369 void setLocalFrameSize(int64_t sz) { LocalFrameSize = sz; }
371 /// Get the size of the local object blob.
372 int64_t getLocalFrameSize() const { return LocalFrameSize; }
374 /// Required alignment of the local object blob,
375 /// which is the strictest alignment of any object in it.
376 void setLocalFrameMaxAlign(unsigned Align) { LocalFrameMaxAlign = Align; }
378 /// Return the required alignment of the local object blob.
379 unsigned getLocalFrameMaxAlign() const { return LocalFrameMaxAlign; }
381 /// Get whether the local allocation blob should be allocated together or
382 /// let PEI allocate the locals in it directly.
383 bool getUseLocalStackAllocationBlock() const {
384 return UseLocalStackAllocationBlock;
387 /// setUseLocalStackAllocationBlock - Set whether the local allocation blob
388 /// should be allocated together or let PEI allocate the locals in it
390 void setUseLocalStackAllocationBlock(bool v) {
391 UseLocalStackAllocationBlock = v;
394 /// Return true if the object was pre-allocated into the local block.
395 bool isObjectPreAllocated(int ObjectIdx) const {
396 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
397 "Invalid Object Idx!");
398 return Objects[ObjectIdx+NumFixedObjects].PreAllocated;
401 /// Return the size of the specified object.
402 int64_t getObjectSize(int ObjectIdx) const {
403 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
404 "Invalid Object Idx!");
405 return Objects[ObjectIdx+NumFixedObjects].Size;
408 /// Change the size of the specified stack object.
409 void setObjectSize(int ObjectIdx, int64_t Size) {
410 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
411 "Invalid Object Idx!");
412 Objects[ObjectIdx+NumFixedObjects].Size = Size;
415 /// Return the alignment of the specified stack object.
416 unsigned getObjectAlignment(int ObjectIdx) const {
417 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
418 "Invalid Object Idx!");
419 return Objects[ObjectIdx+NumFixedObjects].Alignment;
422 /// setObjectAlignment - Change the alignment of the specified stack object.
423 void setObjectAlignment(int ObjectIdx, unsigned Align) {
424 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
425 "Invalid Object Idx!");
426 Objects[ObjectIdx+NumFixedObjects].Alignment = Align;
427 ensureMaxAlignment(Align);
430 /// Return the underlying Alloca of the specified
431 /// stack object if it exists. Returns 0 if none exists.
432 const AllocaInst* getObjectAllocation(int ObjectIdx) const {
433 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
434 "Invalid Object Idx!");
435 return Objects[ObjectIdx+NumFixedObjects].Alloca;
438 /// Return the assigned stack offset of the specified object
439 /// from the incoming stack pointer.
440 int64_t getObjectOffset(int ObjectIdx) const {
441 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
442 "Invalid Object Idx!");
443 assert(!isDeadObjectIndex(ObjectIdx) &&
444 "Getting frame offset for a dead object?");
445 return Objects[ObjectIdx+NumFixedObjects].SPOffset;
448 /// Set the stack frame offset of the specified object. The
449 /// offset is relative to the stack pointer on entry to the function.
450 void setObjectOffset(int ObjectIdx, int64_t SPOffset) {
451 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
452 "Invalid Object Idx!");
453 assert(!isDeadObjectIndex(ObjectIdx) &&
454 "Setting frame offset for a dead object?");
455 Objects[ObjectIdx+NumFixedObjects].SPOffset = SPOffset;
458 /// Return the number of bytes that must be allocated to hold
459 /// all of the fixed size frame objects. This is only valid after
460 /// Prolog/Epilog code insertion has finalized the stack frame layout.
461 uint64_t getStackSize() const { return StackSize; }
463 /// Set the size of the stack.
464 void setStackSize(uint64_t Size) { StackSize = Size; }
466 /// Estimate and return the size of the stack frame.
467 unsigned estimateStackSize(const MachineFunction &MF) const;
469 /// Return the correction for frame offsets.
470 int getOffsetAdjustment() const { return OffsetAdjustment; }
472 /// Set the correction for frame offsets.
473 void setOffsetAdjustment(int Adj) { OffsetAdjustment = Adj; }
475 /// Return the alignment in bytes that this function must be aligned to,
476 /// which is greater than the default stack alignment provided by the target.
477 unsigned getMaxAlignment() const { return MaxAlignment; }
479 /// Make sure the function is at least Align bytes aligned.
480 void ensureMaxAlignment(unsigned Align);
482 /// Return true if this function adjusts the stack -- e.g.,
483 /// when calling another function. This is only valid during and after
484 /// prolog/epilog code insertion.
485 bool adjustsStack() const { return AdjustsStack; }
486 void setAdjustsStack(bool V) { AdjustsStack = V; }
488 /// Return true if the current function has any function calls.
489 bool hasCalls() const { return HasCalls; }
490 void setHasCalls(bool V) { HasCalls = V; }
492 /// Returns true if the function contains opaque dynamic stack adjustments.
493 bool hasOpaqueSPAdjustment() const { return HasOpaqueSPAdjustment; }
494 void setHasOpaqueSPAdjustment(bool B) { HasOpaqueSPAdjustment = B; }
496 /// Returns true if the function calls the llvm.va_start intrinsic.
497 bool hasVAStart() const { return HasVAStart; }
498 void setHasVAStart(bool B) { HasVAStart = B; }
500 /// Returns true if the function is variadic and contains a musttail call.
501 bool hasMustTailInVarArgFunc() const { return HasMustTailInVarArgFunc; }
502 void setHasMustTailInVarArgFunc(bool B) { HasMustTailInVarArgFunc = B; }
504 /// Returns true if the function contains a tail call.
505 bool hasTailCall() const { return HasTailCall; }
506 void setHasTailCall() { HasTailCall = true; }
508 /// Return the maximum size of a call frame that must be
509 /// allocated for an outgoing function call. This is only available if
510 /// CallFrameSetup/Destroy pseudo instructions are used by the target, and
511 /// then only during or after prolog/epilog code insertion.
513 unsigned getMaxCallFrameSize() const { return MaxCallFrameSize; }
514 void setMaxCallFrameSize(unsigned S) { MaxCallFrameSize = S; }
516 /// Create a new object at a fixed location on the stack.
517 /// All fixed objects should be created before other objects are created for
518 /// efficiency. By default, fixed objects are not pointed to by LLVM IR
519 /// values. This returns an index with a negative value.
520 int CreateFixedObject(uint64_t Size, int64_t SPOffset, bool Immutable,
521 bool isAliased = false);
523 /// Create a spill slot at a fixed location on the stack.
524 /// Returns an index with a negative value.
525 int CreateFixedSpillStackObject(uint64_t Size, int64_t SPOffset);
527 /// Returns true if the specified index corresponds to a fixed stack object.
528 bool isFixedObjectIndex(int ObjectIdx) const {
529 return ObjectIdx < 0 && (ObjectIdx >= -(int)NumFixedObjects);
532 /// Returns true if the specified index corresponds
533 /// to an object that might be pointed to by an LLVM IR value.
534 bool isAliasedObjectIndex(int ObjectIdx) const {
535 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
536 "Invalid Object Idx!");
537 return Objects[ObjectIdx+NumFixedObjects].isAliased;
540 /// isImmutableObjectIndex - Returns true if the specified index corresponds
541 /// to an immutable object.
542 bool isImmutableObjectIndex(int ObjectIdx) const {
543 // Tail calling functions can clobber their function arguments.
546 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
547 "Invalid Object Idx!");
548 return Objects[ObjectIdx+NumFixedObjects].isImmutable;
551 /// Returns true if the specified index corresponds to a spill slot.
552 bool isSpillSlotObjectIndex(int ObjectIdx) const {
553 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
554 "Invalid Object Idx!");
555 return Objects[ObjectIdx+NumFixedObjects].isSpillSlot;
558 bool isStatepointSpillSlotObjectIndex(int ObjectIdx) const {
559 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
560 "Invalid Object Idx!");
561 return Objects[ObjectIdx+NumFixedObjects].isStatepointSpillSlot;
564 /// Returns true if the specified index corresponds to a dead object.
565 bool isDeadObjectIndex(int ObjectIdx) const {
566 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
567 "Invalid Object Idx!");
568 return Objects[ObjectIdx+NumFixedObjects].Size == ~0ULL;
571 /// Returns true if the specified index corresponds to a variable sized
573 bool isVariableSizedObjectIndex(int ObjectIdx) const {
574 assert(unsigned(ObjectIdx + NumFixedObjects) < Objects.size() &&
575 "Invalid Object Idx!");
576 return Objects[ObjectIdx + NumFixedObjects].Size == 0;
579 void markAsStatepointSpillSlotObjectIndex(int ObjectIdx) {
580 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
581 "Invalid Object Idx!");
582 Objects[ObjectIdx+NumFixedObjects].isStatepointSpillSlot = true;
583 assert(isStatepointSpillSlotObjectIndex(ObjectIdx) && "inconsistent");
586 /// Create a new statically sized stack object, returning
587 /// a nonnegative identifier to represent it.
588 int CreateStackObject(uint64_t Size, unsigned Alignment, bool isSS,
589 const AllocaInst *Alloca = nullptr);
591 /// Create a new statically sized stack object that represents a spill slot,
592 /// returning a nonnegative identifier to represent it.
593 int CreateSpillStackObject(uint64_t Size, unsigned Alignment);
595 /// Remove or mark dead a statically sized stack object.
596 void RemoveStackObject(int ObjectIdx) {
598 Objects[ObjectIdx+NumFixedObjects].Size = ~0ULL;
601 /// Notify the MachineFrameInfo object that a variable sized object has been
602 /// created. This must be created whenever a variable sized object is
603 /// created, whether or not the index returned is actually used.
604 int CreateVariableSizedObject(unsigned Alignment, const AllocaInst *Alloca);
606 /// Returns a reference to call saved info vector for the current function.
607 const std::vector<CalleeSavedInfo> &getCalleeSavedInfo() const {
611 /// Used by prolog/epilog inserter to set the function's callee saved
613 void setCalleeSavedInfo(const std::vector<CalleeSavedInfo> &CSI) {
617 /// Has the callee saved info been calculated yet?
618 bool isCalleeSavedInfoValid() const { return CSIValid; }
620 void setCalleeSavedInfoValid(bool v) { CSIValid = v; }
622 MachineBasicBlock *getSavePoint() const { return Save; }
623 void setSavePoint(MachineBasicBlock *NewSave) { Save = NewSave; }
624 MachineBasicBlock *getRestorePoint() const { return Restore; }
625 void setRestorePoint(MachineBasicBlock *NewRestore) { Restore = NewRestore; }
627 /// Return a set of physical registers that are pristine.
629 /// Pristine registers hold a value that is useless to the current function,
630 /// but that must be preserved - they are callee saved registers that are not
633 /// Before the PrologueEpilogueInserter has placed the CSR spill code, this
634 /// method always returns an empty set.
635 BitVector getPristineRegs(const MachineFunction &MF) const;
637 /// Used by the MachineFunction printer to print information about
638 /// stack objects. Implemented in MachineFunction.cpp.
639 void print(const MachineFunction &MF, raw_ostream &OS) const;
641 /// dump - Print the function to stderr.
642 void dump(const MachineFunction &MF) const;
645 } // End llvm namespace