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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 
22 namespace llvm {
23 class raw_ostream;
24 class TargetData;
25 class TargetRegisterClass;
26 class Type;
27 class MachineFunction;
28 class MachineBasicBlock;
29 class TargetFrameLowering;
30 class BitVector;
31 
32 /// The CalleeSavedInfo class tracks the information need to locate where a
33 /// callee saved register is in the current frame.
34 class CalleeSavedInfo {
35   unsigned Reg;
36   int FrameIdx;
37 
38 public:
39   explicit CalleeSavedInfo(unsigned R, int FI = 0)
Reg(R)40   : Reg(R), FrameIdx(FI) {}
41 
42   // Accessors.
getReg()43   unsigned getReg()                        const { return Reg; }
getFrameIdx()44   int getFrameIdx()                        const { return FrameIdx; }
setFrameIdx(int FI)45   void setFrameIdx(int FI)                       { FrameIdx = FI; }
46 };
47 
48 /// The MachineFrameInfo class represents an abstract stack frame until
49 /// prolog/epilog code is inserted.  This class is key to allowing stack frame
50 /// representation optimizations, such as frame pointer elimination.  It also
51 /// allows more mundane (but still important) optimizations, such as reordering
52 /// of abstract objects on the stack frame.
53 ///
54 /// To support this, the class assigns unique integer identifiers to stack
55 /// objects requested clients.  These identifiers are negative integers for
56 /// fixed stack objects (such as arguments passed on the stack) or nonnegative
57 /// for objects that may be reordered.  Instructions which refer to stack
58 /// objects use a special MO_FrameIndex operand to represent these frame
59 /// indexes.
60 ///
61 /// Because this class keeps track of all references to the stack frame, it
62 /// knows when a variable sized object is allocated on the stack.  This is the
63 /// sole condition which prevents frame pointer elimination, which is an
64 /// important optimization on register-poor architectures.  Because original
65 /// variable sized alloca's in the source program are the only source of
66 /// variable sized stack objects, it is safe to decide whether there will be
67 /// any variable sized objects before all stack objects are known (for
68 /// example, register allocator spill code never needs variable sized
69 /// objects).
70 ///
71 /// When prolog/epilog code emission is performed, the final stack frame is
72 /// built and the machine instructions are modified to refer to the actual
73 /// stack offsets of the object, eliminating all MO_FrameIndex operands from
74 /// the program.
75 ///
76 /// @brief Abstract Stack Frame Information
77 class MachineFrameInfo {
78 
79   // StackObject - Represent a single object allocated on the stack.
80   struct StackObject {
81     // SPOffset - The offset of this object from the stack pointer on entry to
82     // the function.  This field has no meaning for a variable sized element.
83     int64_t SPOffset;
84 
85     // The size of this object on the stack. 0 means a variable sized object,
86     // ~0ULL means a dead object.
87     uint64_t Size;
88 
89     // Alignment - The required alignment of this stack slot.
90     unsigned Alignment;
91 
92     // isImmutable - If true, the value of the stack object is set before
93     // entering the function and is not modified inside the function. By
94     // default, fixed objects are immutable unless marked otherwise.
95     bool isImmutable;
96 
97     // isSpillSlot - If true the stack object is used as spill slot. It
98     // cannot alias any other memory objects.
99     bool isSpillSlot;
100 
101     // MayNeedSP - If true the stack object triggered the creation of the stack
102     // protector. We should allocate this object right after the stack
103     // protector.
104     bool MayNeedSP;
105 
106     // PreAllocated - If true, the object was mapped into the local frame
107     // block and doesn't need additional handling for allocation beyond that.
108     bool PreAllocated;
109 
StackObjectStackObject110     StackObject(uint64_t Sz, unsigned Al, int64_t SP, bool IM,
111                 bool isSS, bool NSP)
112       : SPOffset(SP), Size(Sz), Alignment(Al), isImmutable(IM),
113         isSpillSlot(isSS), MayNeedSP(NSP), PreAllocated(false) {}
114   };
115 
116   /// Objects - The list of stack objects allocated...
117   ///
118   std::vector<StackObject> Objects;
119 
120   /// NumFixedObjects - This contains the number of fixed objects contained on
121   /// the stack.  Because fixed objects are stored at a negative index in the
122   /// Objects list, this is also the index to the 0th object in the list.
123   ///
124   unsigned NumFixedObjects;
125 
126   /// HasVarSizedObjects - This boolean keeps track of whether any variable
127   /// sized objects have been allocated yet.
128   ///
129   bool HasVarSizedObjects;
130 
131   /// FrameAddressTaken - This boolean keeps track of whether there is a call
132   /// to builtin \@llvm.frameaddress.
133   bool FrameAddressTaken;
134 
135   /// ReturnAddressTaken - This boolean keeps track of whether there is a call
136   /// to builtin \@llvm.returnaddress.
137   bool ReturnAddressTaken;
138 
139   /// StackSize - The prolog/epilog code inserter calculates the final stack
140   /// offsets for all of the fixed size objects, updating the Objects list
141   /// above.  It then updates StackSize to contain the number of bytes that need
142   /// to be allocated on entry to the function.
143   ///
144   uint64_t StackSize;
145 
146   /// OffsetAdjustment - The amount that a frame offset needs to be adjusted to
147   /// have the actual offset from the stack/frame pointer.  The exact usage of
148   /// this is target-dependent, but it is typically used to adjust between
149   /// SP-relative and FP-relative offsets.  E.G., if objects are accessed via
150   /// SP then OffsetAdjustment is zero; if FP is used, OffsetAdjustment is set
151   /// to the distance between the initial SP and the value in FP.  For many
152   /// targets, this value is only used when generating debug info (via
153   /// TargetRegisterInfo::getFrameIndexOffset); when generating code, the
154   /// corresponding adjustments are performed directly.
155   int OffsetAdjustment;
156 
157   /// MaxAlignment - The prolog/epilog code inserter may process objects
158   /// that require greater alignment than the default alignment the target
159   /// provides. To handle this, MaxAlignment is set to the maximum alignment
160   /// needed by the objects on the current frame.  If this is greater than the
161   /// native alignment maintained by the compiler, dynamic alignment code will
162   /// be needed.
163   ///
164   unsigned MaxAlignment;
165 
166   /// AdjustsStack - Set to true if this function adjusts the stack -- e.g.,
167   /// when calling another function. This is only valid during and after
168   /// prolog/epilog code insertion.
169   bool AdjustsStack;
170 
171   /// HasCalls - Set to true if this function has any function calls.
172   bool HasCalls;
173 
174   /// StackProtectorIdx - The frame index for the stack protector.
175   int StackProtectorIdx;
176 
177   /// FunctionContextIdx - The frame index for the function context. Used for
178   /// SjLj exceptions.
179   int FunctionContextIdx;
180 
181   /// MaxCallFrameSize - This contains the size of the largest call frame if the
182   /// target uses frame setup/destroy pseudo instructions (as defined in the
183   /// TargetFrameInfo class).  This information is important for frame pointer
184   /// elimination.  If is only valid during and after prolog/epilog code
185   /// insertion.
186   ///
187   unsigned MaxCallFrameSize;
188 
189   /// CSInfo - The prolog/epilog code inserter fills in this vector with each
190   /// callee saved register saved in the frame.  Beyond its use by the prolog/
191   /// epilog code inserter, this data used for debug info and exception
192   /// handling.
193   std::vector<CalleeSavedInfo> CSInfo;
194 
195   /// CSIValid - Has CSInfo been set yet?
196   bool CSIValid;
197 
198   /// TargetFrameLowering - Target information about frame layout.
199   ///
200   const TargetFrameLowering &TFI;
201 
202   /// LocalFrameObjects - References to frame indices which are mapped
203   /// into the local frame allocation block. <FrameIdx, LocalOffset>
204   SmallVector<std::pair<int, int64_t>, 32> LocalFrameObjects;
205 
206   /// LocalFrameSize - Size of the pre-allocated local frame block.
207   int64_t LocalFrameSize;
208 
209   /// Required alignment of the local object blob, which is the strictest
210   /// alignment of any object in it.
211   unsigned LocalFrameMaxAlign;
212 
213   /// Whether the local object blob needs to be allocated together. If not,
214   /// PEI should ignore the isPreAllocated flags on the stack objects and
215   /// just allocate them normally.
216   bool UseLocalStackAllocationBlock;
217 
218 public:
MachineFrameInfo(const TargetFrameLowering & tfi)219     explicit MachineFrameInfo(const TargetFrameLowering &tfi) : TFI(tfi) {
220     StackSize = NumFixedObjects = OffsetAdjustment = MaxAlignment = 0;
221     HasVarSizedObjects = false;
222     FrameAddressTaken = false;
223     ReturnAddressTaken = false;
224     AdjustsStack = false;
225     HasCalls = false;
226     StackProtectorIdx = -1;
227     FunctionContextIdx = -1;
228     MaxCallFrameSize = 0;
229     CSIValid = false;
230     LocalFrameSize = 0;
231     LocalFrameMaxAlign = 0;
232     UseLocalStackAllocationBlock = false;
233   }
234 
235   /// hasStackObjects - Return true if there are any stack objects in this
236   /// function.
237   ///
hasStackObjects()238   bool hasStackObjects() const { return !Objects.empty(); }
239 
240   /// hasVarSizedObjects - This method may be called any time after instruction
241   /// selection is complete to determine if the stack frame for this function
242   /// contains any variable sized objects.
243   ///
hasVarSizedObjects()244   bool hasVarSizedObjects() const { return HasVarSizedObjects; }
245 
246   /// getStackProtectorIndex/setStackProtectorIndex - Return the index for the
247   /// stack protector object.
248   ///
getStackProtectorIndex()249   int getStackProtectorIndex() const { return StackProtectorIdx; }
setStackProtectorIndex(int I)250   void setStackProtectorIndex(int I) { StackProtectorIdx = I; }
251 
252   /// getFunctionContextIndex/setFunctionContextIndex - Return the index for the
253   /// function context object. This object is used for SjLj exceptions.
getFunctionContextIndex()254   int getFunctionContextIndex() const { return FunctionContextIdx; }
setFunctionContextIndex(int I)255   void setFunctionContextIndex(int I) { FunctionContextIdx = I; }
256 
257   /// isFrameAddressTaken - This method may be called any time after instruction
258   /// selection is complete to determine if there is a call to
259   /// \@llvm.frameaddress in this function.
isFrameAddressTaken()260   bool isFrameAddressTaken() const { return FrameAddressTaken; }
setFrameAddressIsTaken(bool T)261   void setFrameAddressIsTaken(bool T) { FrameAddressTaken = T; }
262 
263   /// isReturnAddressTaken - This method may be called any time after
264   /// instruction selection is complete to determine if there is a call to
265   /// \@llvm.returnaddress in this function.
isReturnAddressTaken()266   bool isReturnAddressTaken() const { return ReturnAddressTaken; }
setReturnAddressIsTaken(bool s)267   void setReturnAddressIsTaken(bool s) { ReturnAddressTaken = s; }
268 
269   /// getObjectIndexBegin - Return the minimum frame object index.
270   ///
getObjectIndexBegin()271   int getObjectIndexBegin() const { return -NumFixedObjects; }
272 
273   /// getObjectIndexEnd - Return one past the maximum frame object index.
274   ///
getObjectIndexEnd()275   int getObjectIndexEnd() const { return (int)Objects.size()-NumFixedObjects; }
276 
277   /// getNumFixedObjects - Return the number of fixed objects.
getNumFixedObjects()278   unsigned getNumFixedObjects() const { return NumFixedObjects; }
279 
280   /// getNumObjects - Return the number of objects.
281   ///
getNumObjects()282   unsigned getNumObjects() const { return Objects.size(); }
283 
284   /// mapLocalFrameObject - Map a frame index into the local object block
mapLocalFrameObject(int ObjectIndex,int64_t Offset)285   void mapLocalFrameObject(int ObjectIndex, int64_t Offset) {
286     LocalFrameObjects.push_back(std::pair<int, int64_t>(ObjectIndex, Offset));
287     Objects[ObjectIndex + NumFixedObjects].PreAllocated = true;
288   }
289 
290   /// getLocalFrameObjectMap - Get the local offset mapping for a for an object
getLocalFrameObjectMap(int i)291   std::pair<int, int64_t> getLocalFrameObjectMap(int i) {
292     assert (i >= 0 && (unsigned)i < LocalFrameObjects.size() &&
293             "Invalid local object reference!");
294     return LocalFrameObjects[i];
295   }
296 
297   /// getLocalFrameObjectCount - Return the number of objects allocated into
298   /// the local object block.
getLocalFrameObjectCount()299   int64_t getLocalFrameObjectCount() { return LocalFrameObjects.size(); }
300 
301   /// setLocalFrameSize - Set the size of the local object blob.
setLocalFrameSize(int64_t sz)302   void setLocalFrameSize(int64_t sz) { LocalFrameSize = sz; }
303 
304   /// getLocalFrameSize - Get the size of the local object blob.
getLocalFrameSize()305   int64_t getLocalFrameSize() const { return LocalFrameSize; }
306 
307   /// setLocalFrameMaxAlign - Required alignment of the local object blob,
308   /// which is the strictest alignment of any object in it.
setLocalFrameMaxAlign(unsigned Align)309   void setLocalFrameMaxAlign(unsigned Align) { LocalFrameMaxAlign = Align; }
310 
311   /// getLocalFrameMaxAlign - Return the required alignment of the local
312   /// object blob.
getLocalFrameMaxAlign()313   unsigned getLocalFrameMaxAlign() const { return LocalFrameMaxAlign; }
314 
315   /// getUseLocalStackAllocationBlock - Get whether the local allocation blob
316   /// should be allocated together or let PEI allocate the locals in it
317   /// directly.
getUseLocalStackAllocationBlock()318   bool getUseLocalStackAllocationBlock() {return UseLocalStackAllocationBlock;}
319 
320   /// setUseLocalStackAllocationBlock - Set whether the local allocation blob
321   /// should be allocated together or let PEI allocate the locals in it
322   /// directly.
setUseLocalStackAllocationBlock(bool v)323   void setUseLocalStackAllocationBlock(bool v) {
324     UseLocalStackAllocationBlock = v;
325   }
326 
327   /// isObjectPreAllocated - Return true if the object was pre-allocated into
328   /// the local block.
isObjectPreAllocated(int ObjectIdx)329   bool isObjectPreAllocated(int ObjectIdx) const {
330     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
331            "Invalid Object Idx!");
332     return Objects[ObjectIdx+NumFixedObjects].PreAllocated;
333   }
334 
335   /// getObjectSize - Return the size of the specified object.
336   ///
getObjectSize(int ObjectIdx)337   int64_t getObjectSize(int ObjectIdx) const {
338     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
339            "Invalid Object Idx!");
340     return Objects[ObjectIdx+NumFixedObjects].Size;
341   }
342 
343   /// setObjectSize - Change the size of the specified stack object.
setObjectSize(int ObjectIdx,int64_t Size)344   void setObjectSize(int ObjectIdx, int64_t Size) {
345     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
346            "Invalid Object Idx!");
347     Objects[ObjectIdx+NumFixedObjects].Size = Size;
348   }
349 
350   /// getObjectAlignment - Return the alignment of the specified stack object.
getObjectAlignment(int ObjectIdx)351   unsigned getObjectAlignment(int ObjectIdx) const {
352     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
353            "Invalid Object Idx!");
354     return Objects[ObjectIdx+NumFixedObjects].Alignment;
355   }
356 
357   /// setObjectAlignment - Change the alignment of the specified stack object.
setObjectAlignment(int ObjectIdx,unsigned Align)358   void setObjectAlignment(int ObjectIdx, unsigned Align) {
359     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
360            "Invalid Object Idx!");
361     Objects[ObjectIdx+NumFixedObjects].Alignment = Align;
362     MaxAlignment = std::max(MaxAlignment, Align);
363   }
364 
365   /// NeedsStackProtector - Returns true if the object may need stack
366   /// protectors.
MayNeedStackProtector(int ObjectIdx)367   bool MayNeedStackProtector(int ObjectIdx) const {
368     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
369            "Invalid Object Idx!");
370     return Objects[ObjectIdx+NumFixedObjects].MayNeedSP;
371   }
372 
373   /// getObjectOffset - Return the assigned stack offset of the specified object
374   /// from the incoming stack pointer.
375   ///
getObjectOffset(int ObjectIdx)376   int64_t getObjectOffset(int ObjectIdx) const {
377     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
378            "Invalid Object Idx!");
379     assert(!isDeadObjectIndex(ObjectIdx) &&
380            "Getting frame offset for a dead object?");
381     return Objects[ObjectIdx+NumFixedObjects].SPOffset;
382   }
383 
384   /// setObjectOffset - Set the stack frame offset of the specified object.  The
385   /// offset is relative to the stack pointer on entry to the function.
386   ///
setObjectOffset(int ObjectIdx,int64_t SPOffset)387   void setObjectOffset(int ObjectIdx, int64_t SPOffset) {
388     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
389            "Invalid Object Idx!");
390     assert(!isDeadObjectIndex(ObjectIdx) &&
391            "Setting frame offset for a dead object?");
392     Objects[ObjectIdx+NumFixedObjects].SPOffset = SPOffset;
393   }
394 
395   /// getStackSize - Return the number of bytes that must be allocated to hold
396   /// all of the fixed size frame objects.  This is only valid after
397   /// Prolog/Epilog code insertion has finalized the stack frame layout.
398   ///
getStackSize()399   uint64_t getStackSize() const { return StackSize; }
400 
401   /// setStackSize - Set the size of the stack...
402   ///
setStackSize(uint64_t Size)403   void setStackSize(uint64_t Size) { StackSize = Size; }
404 
405   /// getOffsetAdjustment - Return the correction for frame offsets.
406   ///
getOffsetAdjustment()407   int getOffsetAdjustment() const { return OffsetAdjustment; }
408 
409   /// setOffsetAdjustment - Set the correction for frame offsets.
410   ///
setOffsetAdjustment(int Adj)411   void setOffsetAdjustment(int Adj) { OffsetAdjustment = Adj; }
412 
413   /// getMaxAlignment - Return the alignment in bytes that this function must be
414   /// aligned to, which is greater than the default stack alignment provided by
415   /// the target.
416   ///
getMaxAlignment()417   unsigned getMaxAlignment() const { return MaxAlignment; }
418 
419   /// setMaxAlignment - Set the preferred alignment.
420   ///
setMaxAlignment(unsigned Align)421   void setMaxAlignment(unsigned Align) { MaxAlignment = Align; }
422 
423   /// AdjustsStack - Return true if this function adjusts the stack -- e.g.,
424   /// when calling another function. This is only valid during and after
425   /// prolog/epilog code insertion.
adjustsStack()426   bool adjustsStack() const { return AdjustsStack; }
setAdjustsStack(bool V)427   void setAdjustsStack(bool V) { AdjustsStack = V; }
428 
429   /// hasCalls - Return true if the current function has any function calls.
hasCalls()430   bool hasCalls() const { return HasCalls; }
setHasCalls(bool V)431   void setHasCalls(bool V) { HasCalls = V; }
432 
433   /// getMaxCallFrameSize - Return the maximum size of a call frame that must be
434   /// allocated for an outgoing function call.  This is only available if
435   /// CallFrameSetup/Destroy pseudo instructions are used by the target, and
436   /// then only during or after prolog/epilog code insertion.
437   ///
getMaxCallFrameSize()438   unsigned getMaxCallFrameSize() const { return MaxCallFrameSize; }
setMaxCallFrameSize(unsigned S)439   void setMaxCallFrameSize(unsigned S) { MaxCallFrameSize = S; }
440 
441   /// CreateFixedObject - Create a new object at a fixed location on the stack.
442   /// All fixed objects should be created before other objects are created for
443   /// efficiency. By default, fixed objects are immutable. This returns an
444   /// index with a negative value.
445   ///
446   int CreateFixedObject(uint64_t Size, int64_t SPOffset, bool Immutable);
447 
448 
449   /// isFixedObjectIndex - Returns true if the specified index corresponds to a
450   /// fixed stack object.
isFixedObjectIndex(int ObjectIdx)451   bool isFixedObjectIndex(int ObjectIdx) const {
452     return ObjectIdx < 0 && (ObjectIdx >= -(int)NumFixedObjects);
453   }
454 
455   /// isImmutableObjectIndex - Returns true if the specified index corresponds
456   /// to an immutable object.
isImmutableObjectIndex(int ObjectIdx)457   bool isImmutableObjectIndex(int ObjectIdx) const {
458     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
459            "Invalid Object Idx!");
460     return Objects[ObjectIdx+NumFixedObjects].isImmutable;
461   }
462 
463   /// isSpillSlotObjectIndex - Returns true if the specified index corresponds
464   /// to a spill slot..
isSpillSlotObjectIndex(int ObjectIdx)465   bool isSpillSlotObjectIndex(int ObjectIdx) const {
466     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
467            "Invalid Object Idx!");
468     return Objects[ObjectIdx+NumFixedObjects].isSpillSlot;
469   }
470 
471   /// isDeadObjectIndex - Returns true if the specified index corresponds to
472   /// a dead object.
isDeadObjectIndex(int ObjectIdx)473   bool isDeadObjectIndex(int ObjectIdx) const {
474     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
475            "Invalid Object Idx!");
476     return Objects[ObjectIdx+NumFixedObjects].Size == ~0ULL;
477   }
478 
479   /// CreateStackObject - Create a new statically sized stack object, returning
480   /// a nonnegative identifier to represent it.
481   ///
482   int CreateStackObject(uint64_t Size, unsigned Alignment, bool isSS,
483                         bool MayNeedSP = false) {
484     assert(Size != 0 && "Cannot allocate zero size stack objects!");
485     Objects.push_back(StackObject(Size, Alignment, 0, false, isSS, MayNeedSP));
486     int Index = (int)Objects.size() - NumFixedObjects - 1;
487     assert(Index >= 0 && "Bad frame index!");
488     MaxAlignment = std::max(MaxAlignment, Alignment);
489     return Index;
490   }
491 
492   /// CreateSpillStackObject - Create a new statically sized stack object that
493   /// represents a spill slot, returning a nonnegative identifier to represent
494   /// it.
495   ///
CreateSpillStackObject(uint64_t Size,unsigned Alignment)496   int CreateSpillStackObject(uint64_t Size, unsigned Alignment) {
497     CreateStackObject(Size, Alignment, true, false);
498     int Index = (int)Objects.size() - NumFixedObjects - 1;
499     MaxAlignment = std::max(MaxAlignment, Alignment);
500     return Index;
501   }
502 
503   /// RemoveStackObject - Remove or mark dead a statically sized stack object.
504   ///
RemoveStackObject(int ObjectIdx)505   void RemoveStackObject(int ObjectIdx) {
506     // Mark it dead.
507     Objects[ObjectIdx+NumFixedObjects].Size = ~0ULL;
508   }
509 
510   /// CreateVariableSizedObject - Notify the MachineFrameInfo object that a
511   /// variable sized object has been created.  This must be created whenever a
512   /// variable sized object is created, whether or not the index returned is
513   /// actually used.
514   ///
CreateVariableSizedObject(unsigned Alignment)515   int CreateVariableSizedObject(unsigned Alignment) {
516     HasVarSizedObjects = true;
517     Objects.push_back(StackObject(0, Alignment, 0, false, false, true));
518     MaxAlignment = std::max(MaxAlignment, Alignment);
519     return (int)Objects.size()-NumFixedObjects-1;
520   }
521 
522   /// getCalleeSavedInfo - Returns a reference to call saved info vector for the
523   /// current function.
getCalleeSavedInfo()524   const std::vector<CalleeSavedInfo> &getCalleeSavedInfo() const {
525     return CSInfo;
526   }
527 
528   /// setCalleeSavedInfo - Used by prolog/epilog inserter to set the function's
529   /// callee saved information.
setCalleeSavedInfo(const std::vector<CalleeSavedInfo> & CSI)530   void setCalleeSavedInfo(const std::vector<CalleeSavedInfo> &CSI) {
531     CSInfo = CSI;
532   }
533 
534   /// isCalleeSavedInfoValid - Has the callee saved info been calculated yet?
isCalleeSavedInfoValid()535   bool isCalleeSavedInfoValid() const { return CSIValid; }
536 
setCalleeSavedInfoValid(bool v)537   void setCalleeSavedInfoValid(bool v) { CSIValid = v; }
538 
539   /// getPristineRegs - Return a set of physical registers that are pristine on
540   /// entry to the MBB.
541   ///
542   /// Pristine registers hold a value that is useless to the current function,
543   /// but that must be preserved - they are callee saved registers that have not
544   /// been saved yet.
545   ///
546   /// Before the PrologueEpilogueInserter has placed the CSR spill code, this
547   /// method always returns an empty set.
548   BitVector getPristineRegs(const MachineBasicBlock *MBB) const;
549 
550   /// print - Used by the MachineFunction printer to print information about
551   /// stack objects. Implemented in MachineFunction.cpp
552   ///
553   void print(const MachineFunction &MF, raw_ostream &OS) const;
554 
555   /// dump - Print the function to stderr.
556   void dump(const MachineFunction &MF) const;
557 };
558 
559 } // End llvm namespace
560 
561 #endif
562