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 DataLayout;
25 class TargetRegisterClass;
26 class Type;
27 class MachineFunction;
28 class MachineBasicBlock;
29 class TargetFrameLowering;
30 class TargetMachine;
31 class BitVector;
32 class Value;
33 class AllocaInst;
34 
35 /// The CalleeSavedInfo class tracks the information need to locate where a
36 /// callee saved register is in the current frame.
37 class CalleeSavedInfo {
38   unsigned Reg;
39   int FrameIdx;
40 
41 public:
42   explicit CalleeSavedInfo(unsigned R, int FI = 0)
Reg(R)43   : Reg(R), FrameIdx(FI) {}
44 
45   // Accessors.
getReg()46   unsigned getReg()                        const { return Reg; }
getFrameIdx()47   int getFrameIdx()                        const { return FrameIdx; }
setFrameIdx(int FI)48   void setFrameIdx(int FI)                       { FrameIdx = FI; }
49 };
50 
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.
56 ///
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
62 /// indexes.
63 ///
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
72 /// objects).
73 ///
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
77 /// the program.
78 ///
79 /// @brief Abstract Stack Frame Information
80 class MachineFrameInfo {
81 
82   // StackObject - Represent a single object allocated on the stack.
83   struct StackObject {
84     // SPOffset - 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.
86     int64_t SPOffset;
87 
88     // The size of this object on the stack. 0 means a variable sized object,
89     // ~0ULL means a dead object.
90     uint64_t Size;
91 
92     // Alignment - The required alignment of this stack slot.
93     unsigned Alignment;
94 
95     // isImmutable - 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.
98     bool isImmutable;
99 
100     // isSpillSlot - If true the stack object is used as spill slot. It
101     // cannot alias any other memory objects.
102     bool isSpillSlot;
103 
104     /// Alloca - If this stack object is originated from an Alloca instruction
105     /// this value saves the original IR allocation. Can be NULL.
106     const AllocaInst *Alloca;
107 
108     // PreAllocated - If true, the object was mapped into the local frame
109     // block and doesn't need additional handling for allocation beyond that.
110     bool PreAllocated;
111 
112     // If true, an LLVM IR value might point to this object.
113     // Normally, spill slots and fixed-offset objects don't alias IR-accessible
114     // objects, but there are exceptions (on PowerPC, for example, some byval
115     // arguments have ABI-prescribed offsets).
116     bool isAliased;
117 
StackObjectStackObject118     StackObject(uint64_t Sz, unsigned Al, int64_t SP, bool IM,
119                 bool isSS, const AllocaInst *Val, bool A)
120       : SPOffset(SP), Size(Sz), Alignment(Al), isImmutable(IM),
121         isSpillSlot(isSS), Alloca(Val), PreAllocated(false), isAliased(A) {}
122   };
123 
124   /// StackAlignment - The alignment of the stack.
125   unsigned StackAlignment;
126 
127   /// StackRealignable - Can the stack be realigned.
128   bool StackRealignable;
129 
130   /// Objects - The list of stack objects allocated...
131   ///
132   std::vector<StackObject> Objects;
133 
134   /// NumFixedObjects - This contains the number of fixed objects contained on
135   /// the stack.  Because fixed objects are stored at a negative index in the
136   /// Objects list, this is also the index to the 0th object in the list.
137   ///
138   unsigned NumFixedObjects;
139 
140   /// HasVarSizedObjects - This boolean keeps track of whether any variable
141   /// sized objects have been allocated yet.
142   ///
143   bool HasVarSizedObjects;
144 
145   /// FrameAddressTaken - This boolean keeps track of whether there is a call
146   /// to builtin \@llvm.frameaddress.
147   bool FrameAddressTaken;
148 
149   /// ReturnAddressTaken - This boolean keeps track of whether there is a call
150   /// to builtin \@llvm.returnaddress.
151   bool ReturnAddressTaken;
152 
153   /// HasStackMap - This boolean keeps track of whether there is a call
154   /// to builtin \@llvm.experimental.stackmap.
155   bool HasStackMap;
156 
157   /// HasPatchPoint - This boolean keeps track of whether there is a call
158   /// to builtin \@llvm.experimental.patchpoint.
159   bool HasPatchPoint;
160 
161   /// StackSize - The prolog/epilog code inserter calculates the final stack
162   /// offsets for all of the fixed size objects, updating the Objects list
163   /// above.  It then updates StackSize to contain the number of bytes that need
164   /// to be allocated on entry to the function.
165   ///
166   uint64_t StackSize;
167 
168   /// OffsetAdjustment - The amount that a frame offset needs to be adjusted to
169   /// have the actual offset from the stack/frame pointer.  The exact usage of
170   /// this is target-dependent, but it is typically used to adjust between
171   /// SP-relative and FP-relative offsets.  E.G., if objects are accessed via
172   /// SP then OffsetAdjustment is zero; if FP is used, OffsetAdjustment is set
173   /// to the distance between the initial SP and the value in FP.  For many
174   /// targets, this value is only used when generating debug info (via
175   /// TargetRegisterInfo::getFrameIndexOffset); when generating code, the
176   /// corresponding adjustments are performed directly.
177   int OffsetAdjustment;
178 
179   /// MaxAlignment - The prolog/epilog code inserter may process objects
180   /// that require greater alignment than the default alignment the target
181   /// provides. To handle this, MaxAlignment is set to the maximum alignment
182   /// needed by the objects on the current frame.  If this is greater than the
183   /// native alignment maintained by the compiler, dynamic alignment code will
184   /// be needed.
185   ///
186   unsigned MaxAlignment;
187 
188   /// AdjustsStack - Set to true if this function adjusts the stack -- e.g.,
189   /// when calling another function. This is only valid during and after
190   /// prolog/epilog code insertion.
191   bool AdjustsStack;
192 
193   /// HasCalls - Set to true if this function has any function calls.
194   bool HasCalls;
195 
196   /// StackProtectorIdx - The frame index for the stack protector.
197   int StackProtectorIdx;
198 
199   /// FunctionContextIdx - The frame index for the function context. Used for
200   /// SjLj exceptions.
201   int FunctionContextIdx;
202 
203   /// MaxCallFrameSize - This contains the size of the largest call frame if the
204   /// target uses frame setup/destroy pseudo instructions (as defined in the
205   /// TargetFrameInfo class).  This information is important for frame pointer
206   /// elimination.  If is only valid during and after prolog/epilog code
207   /// insertion.
208   ///
209   unsigned MaxCallFrameSize;
210 
211   /// CSInfo - The prolog/epilog code inserter fills in this vector with each
212   /// callee saved register saved in the frame.  Beyond its use by the prolog/
213   /// epilog code inserter, this data used for debug info and exception
214   /// handling.
215   std::vector<CalleeSavedInfo> CSInfo;
216 
217   /// CSIValid - Has CSInfo been set yet?
218   bool CSIValid;
219 
220   /// LocalFrameObjects - References to frame indices which are mapped
221   /// into the local frame allocation block. <FrameIdx, LocalOffset>
222   SmallVector<std::pair<int, int64_t>, 32> LocalFrameObjects;
223 
224   /// LocalFrameSize - Size of the pre-allocated local frame block.
225   int64_t LocalFrameSize;
226 
227   /// Required alignment of the local object blob, which is the strictest
228   /// alignment of any object in it.
229   unsigned LocalFrameMaxAlign;
230 
231   /// Whether the local object blob needs to be allocated together. If not,
232   /// PEI should ignore the isPreAllocated flags on the stack objects and
233   /// just allocate them normally.
234   bool UseLocalStackAllocationBlock;
235 
236   /// Whether the "realign-stack" option is on.
237   bool RealignOption;
238 
239   /// True if the function includes inline assembly that adjusts the stack
240   /// pointer.
241   bool HasInlineAsmWithSPAdjust;
242 
243   /// True if the function contains a call to the llvm.vastart intrinsic.
244   bool HasVAStart;
245 
246   /// True if this is a varargs function that contains a musttail call.
247   bool HasMustTailInVarArgFunc;
248 
249 public:
MachineFrameInfo(unsigned StackAlign,bool isStackRealign,bool RealignOpt)250   explicit MachineFrameInfo(unsigned StackAlign, bool isStackRealign,
251                             bool RealignOpt)
252       : StackAlignment(StackAlign), StackRealignable(isStackRealign),
253         RealignOption(RealignOpt) {
254     StackSize = NumFixedObjects = OffsetAdjustment = MaxAlignment = 0;
255     HasVarSizedObjects = false;
256     FrameAddressTaken = false;
257     ReturnAddressTaken = false;
258     HasStackMap = false;
259     HasPatchPoint = false;
260     AdjustsStack = false;
261     HasCalls = false;
262     StackProtectorIdx = -1;
263     FunctionContextIdx = -1;
264     MaxCallFrameSize = 0;
265     CSIValid = false;
266     LocalFrameSize = 0;
267     LocalFrameMaxAlign = 0;
268     UseLocalStackAllocationBlock = false;
269     HasInlineAsmWithSPAdjust = false;
270     HasVAStart = false;
271     HasMustTailInVarArgFunc = false;
272   }
273 
274   /// hasStackObjects - Return true if there are any stack objects in this
275   /// function.
276   ///
hasStackObjects()277   bool hasStackObjects() const { return !Objects.empty(); }
278 
279   /// hasVarSizedObjects - This method may be called any time after instruction
280   /// selection is complete to determine if the stack frame for this function
281   /// contains any variable sized objects.
282   ///
hasVarSizedObjects()283   bool hasVarSizedObjects() const { return HasVarSizedObjects; }
284 
285   /// getStackProtectorIndex/setStackProtectorIndex - Return the index for the
286   /// stack protector object.
287   ///
getStackProtectorIndex()288   int getStackProtectorIndex() const { return StackProtectorIdx; }
setStackProtectorIndex(int I)289   void setStackProtectorIndex(int I) { StackProtectorIdx = I; }
290 
291   /// getFunctionContextIndex/setFunctionContextIndex - Return the index for the
292   /// function context object. This object is used for SjLj exceptions.
getFunctionContextIndex()293   int getFunctionContextIndex() const { return FunctionContextIdx; }
setFunctionContextIndex(int I)294   void setFunctionContextIndex(int I) { FunctionContextIdx = I; }
295 
296   /// isFrameAddressTaken - This method may be called any time after instruction
297   /// selection is complete to determine if there is a call to
298   /// \@llvm.frameaddress in this function.
isFrameAddressTaken()299   bool isFrameAddressTaken() const { return FrameAddressTaken; }
setFrameAddressIsTaken(bool T)300   void setFrameAddressIsTaken(bool T) { FrameAddressTaken = T; }
301 
302   /// isReturnAddressTaken - This method may be called any time after
303   /// instruction selection is complete to determine if there is a call to
304   /// \@llvm.returnaddress in this function.
isReturnAddressTaken()305   bool isReturnAddressTaken() const { return ReturnAddressTaken; }
setReturnAddressIsTaken(bool s)306   void setReturnAddressIsTaken(bool s) { ReturnAddressTaken = s; }
307 
308   /// hasStackMap - This method may be called any time after instruction
309   /// selection is complete to determine if there is a call to builtin
310   /// \@llvm.experimental.stackmap.
hasStackMap()311   bool hasStackMap() const { return HasStackMap; }
312   void setHasStackMap(bool s = true) { HasStackMap = s; }
313 
314   /// hasPatchPoint - This method may be called any time after instruction
315   /// selection is complete to determine if there is a call to builtin
316   /// \@llvm.experimental.patchpoint.
hasPatchPoint()317   bool hasPatchPoint() const { return HasPatchPoint; }
318   void setHasPatchPoint(bool s = true) { HasPatchPoint = s; }
319 
320   /// getObjectIndexBegin - Return the minimum frame object index.
321   ///
getObjectIndexBegin()322   int getObjectIndexBegin() const { return -NumFixedObjects; }
323 
324   /// getObjectIndexEnd - Return one past the maximum frame object index.
325   ///
getObjectIndexEnd()326   int getObjectIndexEnd() const { return (int)Objects.size()-NumFixedObjects; }
327 
328   /// getNumFixedObjects - Return the number of fixed objects.
getNumFixedObjects()329   unsigned getNumFixedObjects() const { return NumFixedObjects; }
330 
331   /// getNumObjects - Return the number of objects.
332   ///
getNumObjects()333   unsigned getNumObjects() const { return Objects.size(); }
334 
335   /// mapLocalFrameObject - Map a frame index into the local object block
mapLocalFrameObject(int ObjectIndex,int64_t Offset)336   void mapLocalFrameObject(int ObjectIndex, int64_t Offset) {
337     LocalFrameObjects.push_back(std::pair<int, int64_t>(ObjectIndex, Offset));
338     Objects[ObjectIndex + NumFixedObjects].PreAllocated = true;
339   }
340 
341   /// getLocalFrameObjectMap - Get the local offset mapping for a for an object
getLocalFrameObjectMap(int i)342   std::pair<int, int64_t> getLocalFrameObjectMap(int i) {
343     assert (i >= 0 && (unsigned)i < LocalFrameObjects.size() &&
344             "Invalid local object reference!");
345     return LocalFrameObjects[i];
346   }
347 
348   /// getLocalFrameObjectCount - Return the number of objects allocated into
349   /// the local object block.
getLocalFrameObjectCount()350   int64_t getLocalFrameObjectCount() { return LocalFrameObjects.size(); }
351 
352   /// setLocalFrameSize - Set the size of the local object blob.
setLocalFrameSize(int64_t sz)353   void setLocalFrameSize(int64_t sz) { LocalFrameSize = sz; }
354 
355   /// getLocalFrameSize - Get the size of the local object blob.
getLocalFrameSize()356   int64_t getLocalFrameSize() const { return LocalFrameSize; }
357 
358   /// setLocalFrameMaxAlign - Required alignment of the local object blob,
359   /// which is the strictest alignment of any object in it.
setLocalFrameMaxAlign(unsigned Align)360   void setLocalFrameMaxAlign(unsigned Align) { LocalFrameMaxAlign = Align; }
361 
362   /// getLocalFrameMaxAlign - Return the required alignment of the local
363   /// object blob.
getLocalFrameMaxAlign()364   unsigned getLocalFrameMaxAlign() const { return LocalFrameMaxAlign; }
365 
366   /// getUseLocalStackAllocationBlock - Get whether the local allocation blob
367   /// should be allocated together or let PEI allocate the locals in it
368   /// directly.
getUseLocalStackAllocationBlock()369   bool getUseLocalStackAllocationBlock() {return UseLocalStackAllocationBlock;}
370 
371   /// setUseLocalStackAllocationBlock - Set whether the local allocation blob
372   /// should be allocated together or let PEI allocate the locals in it
373   /// directly.
setUseLocalStackAllocationBlock(bool v)374   void setUseLocalStackAllocationBlock(bool v) {
375     UseLocalStackAllocationBlock = v;
376   }
377 
378   /// isObjectPreAllocated - Return true if the object was pre-allocated into
379   /// the local block.
isObjectPreAllocated(int ObjectIdx)380   bool isObjectPreAllocated(int ObjectIdx) const {
381     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
382            "Invalid Object Idx!");
383     return Objects[ObjectIdx+NumFixedObjects].PreAllocated;
384   }
385 
386   /// getObjectSize - Return the size of the specified object.
387   ///
getObjectSize(int ObjectIdx)388   int64_t getObjectSize(int ObjectIdx) const {
389     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
390            "Invalid Object Idx!");
391     return Objects[ObjectIdx+NumFixedObjects].Size;
392   }
393 
394   /// setObjectSize - Change the size of the specified stack object.
setObjectSize(int ObjectIdx,int64_t Size)395   void setObjectSize(int ObjectIdx, int64_t Size) {
396     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
397            "Invalid Object Idx!");
398     Objects[ObjectIdx+NumFixedObjects].Size = Size;
399   }
400 
401   /// getObjectAlignment - Return the alignment of the specified stack object.
getObjectAlignment(int ObjectIdx)402   unsigned getObjectAlignment(int ObjectIdx) const {
403     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
404            "Invalid Object Idx!");
405     return Objects[ObjectIdx+NumFixedObjects].Alignment;
406   }
407 
408   /// setObjectAlignment - Change the alignment of the specified stack object.
setObjectAlignment(int ObjectIdx,unsigned Align)409   void setObjectAlignment(int ObjectIdx, unsigned Align) {
410     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
411            "Invalid Object Idx!");
412     Objects[ObjectIdx+NumFixedObjects].Alignment = Align;
413     ensureMaxAlignment(Align);
414   }
415 
416   /// getObjectAllocation - Return the underlying Alloca of the specified
417   /// stack object if it exists. Returns 0 if none exists.
getObjectAllocation(int ObjectIdx)418   const AllocaInst* getObjectAllocation(int ObjectIdx) const {
419     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
420            "Invalid Object Idx!");
421     return Objects[ObjectIdx+NumFixedObjects].Alloca;
422   }
423 
424   /// getObjectOffset - Return the assigned stack offset of the specified object
425   /// from the incoming stack pointer.
426   ///
getObjectOffset(int ObjectIdx)427   int64_t getObjectOffset(int ObjectIdx) const {
428     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
429            "Invalid Object Idx!");
430     assert(!isDeadObjectIndex(ObjectIdx) &&
431            "Getting frame offset for a dead object?");
432     return Objects[ObjectIdx+NumFixedObjects].SPOffset;
433   }
434 
435   /// setObjectOffset - Set the stack frame offset of the specified object.  The
436   /// offset is relative to the stack pointer on entry to the function.
437   ///
setObjectOffset(int ObjectIdx,int64_t SPOffset)438   void setObjectOffset(int ObjectIdx, int64_t SPOffset) {
439     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
440            "Invalid Object Idx!");
441     assert(!isDeadObjectIndex(ObjectIdx) &&
442            "Setting frame offset for a dead object?");
443     Objects[ObjectIdx+NumFixedObjects].SPOffset = SPOffset;
444   }
445 
446   /// getStackSize - Return the number of bytes that must be allocated to hold
447   /// all of the fixed size frame objects.  This is only valid after
448   /// Prolog/Epilog code insertion has finalized the stack frame layout.
449   ///
getStackSize()450   uint64_t getStackSize() const { return StackSize; }
451 
452   /// setStackSize - Set the size of the stack...
453   ///
setStackSize(uint64_t Size)454   void setStackSize(uint64_t Size) { StackSize = Size; }
455 
456   /// Estimate and return the size of the stack frame.
457   unsigned estimateStackSize(const MachineFunction &MF) const;
458 
459   /// getOffsetAdjustment - Return the correction for frame offsets.
460   ///
getOffsetAdjustment()461   int getOffsetAdjustment() const { return OffsetAdjustment; }
462 
463   /// setOffsetAdjustment - Set the correction for frame offsets.
464   ///
setOffsetAdjustment(int Adj)465   void setOffsetAdjustment(int Adj) { OffsetAdjustment = Adj; }
466 
467   /// getMaxAlignment - Return the alignment in bytes that this function must be
468   /// aligned to, which is greater than the default stack alignment provided by
469   /// the target.
470   ///
getMaxAlignment()471   unsigned getMaxAlignment() const { return MaxAlignment; }
472 
473   /// ensureMaxAlignment - Make sure the function is at least Align bytes
474   /// aligned.
475   void ensureMaxAlignment(unsigned Align);
476 
477   /// AdjustsStack - Return true if this function adjusts the stack -- e.g.,
478   /// when calling another function. This is only valid during and after
479   /// prolog/epilog code insertion.
adjustsStack()480   bool adjustsStack() const { return AdjustsStack; }
setAdjustsStack(bool V)481   void setAdjustsStack(bool V) { AdjustsStack = V; }
482 
483   /// hasCalls - Return true if the current function has any function calls.
hasCalls()484   bool hasCalls() const { return HasCalls; }
setHasCalls(bool V)485   void setHasCalls(bool V) { HasCalls = V; }
486 
487   /// Returns true if the function contains any stack-adjusting inline assembly.
hasInlineAsmWithSPAdjust()488   bool hasInlineAsmWithSPAdjust() const { return HasInlineAsmWithSPAdjust; }
setHasInlineAsmWithSPAdjust(bool B)489   void setHasInlineAsmWithSPAdjust(bool B) { HasInlineAsmWithSPAdjust = B; }
490 
491   /// Returns true if the function calls the llvm.va_start intrinsic.
hasVAStart()492   bool hasVAStart() const { return HasVAStart; }
setHasVAStart(bool B)493   void setHasVAStart(bool B) { HasVAStart = B; }
494 
495   /// Returns true if the function is variadic and contains a musttail call.
hasMustTailInVarArgFunc()496   bool hasMustTailInVarArgFunc() const { return HasMustTailInVarArgFunc; }
setHasMustTailInVarArgFunc(bool B)497   void setHasMustTailInVarArgFunc(bool B) { HasMustTailInVarArgFunc = B; }
498 
499   /// getMaxCallFrameSize - Return the maximum size of a call frame that must be
500   /// allocated for an outgoing function call.  This is only available if
501   /// CallFrameSetup/Destroy pseudo instructions are used by the target, and
502   /// then only during or after prolog/epilog code insertion.
503   ///
getMaxCallFrameSize()504   unsigned getMaxCallFrameSize() const { return MaxCallFrameSize; }
setMaxCallFrameSize(unsigned S)505   void setMaxCallFrameSize(unsigned S) { MaxCallFrameSize = S; }
506 
507   /// CreateFixedObject - Create a new object at a fixed location on the stack.
508   /// All fixed objects should be created before other objects are created for
509   /// efficiency. By default, fixed objects are not pointed to by LLVM IR
510   /// values. This returns an index with a negative value.
511   ///
512   int CreateFixedObject(uint64_t Size, int64_t SPOffset, bool Immutable,
513                         bool isAliased = false);
514 
515   /// CreateFixedSpillStackObject - Create a spill slot at a fixed location
516   /// on the stack.  Returns an index with a negative value.
517   int CreateFixedSpillStackObject(uint64_t Size, int64_t SPOffset);
518 
519   /// isFixedObjectIndex - Returns true if the specified index corresponds to a
520   /// fixed stack object.
isFixedObjectIndex(int ObjectIdx)521   bool isFixedObjectIndex(int ObjectIdx) const {
522     return ObjectIdx < 0 && (ObjectIdx >= -(int)NumFixedObjects);
523   }
524 
525   /// isAliasedObjectIndex - Returns true if the specified index corresponds
526   /// to an object that might be pointed to by an LLVM IR value.
isAliasedObjectIndex(int ObjectIdx)527   bool isAliasedObjectIndex(int ObjectIdx) const {
528     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
529            "Invalid Object Idx!");
530     return Objects[ObjectIdx+NumFixedObjects].isAliased;
531   }
532 
533   /// isImmutableObjectIndex - Returns true if the specified index corresponds
534   /// to an immutable object.
isImmutableObjectIndex(int ObjectIdx)535   bool isImmutableObjectIndex(int ObjectIdx) const {
536     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
537            "Invalid Object Idx!");
538     return Objects[ObjectIdx+NumFixedObjects].isImmutable;
539   }
540 
541   /// isSpillSlotObjectIndex - Returns true if the specified index corresponds
542   /// to a spill slot..
isSpillSlotObjectIndex(int ObjectIdx)543   bool isSpillSlotObjectIndex(int ObjectIdx) const {
544     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
545            "Invalid Object Idx!");
546     return Objects[ObjectIdx+NumFixedObjects].isSpillSlot;
547   }
548 
549   /// isDeadObjectIndex - Returns true if the specified index corresponds to
550   /// a dead object.
isDeadObjectIndex(int ObjectIdx)551   bool isDeadObjectIndex(int ObjectIdx) const {
552     assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
553            "Invalid Object Idx!");
554     return Objects[ObjectIdx+NumFixedObjects].Size == ~0ULL;
555   }
556 
557   /// CreateStackObject - Create a new statically sized stack object, returning
558   /// a nonnegative identifier to represent it.
559   ///
560   int CreateStackObject(uint64_t Size, unsigned Alignment, bool isSS,
561                         const AllocaInst *Alloca = nullptr);
562 
563   /// CreateSpillStackObject - Create a new statically sized stack object that
564   /// represents a spill slot, returning a nonnegative identifier to represent
565   /// it.
566   ///
567   int CreateSpillStackObject(uint64_t Size, unsigned Alignment);
568 
569   /// RemoveStackObject - Remove or mark dead a statically sized stack object.
570   ///
RemoveStackObject(int ObjectIdx)571   void RemoveStackObject(int ObjectIdx) {
572     // Mark it dead.
573     Objects[ObjectIdx+NumFixedObjects].Size = ~0ULL;
574   }
575 
576   /// CreateVariableSizedObject - Notify the MachineFrameInfo object that a
577   /// variable sized object has been created.  This must be created whenever a
578   /// variable sized object is created, whether or not the index returned is
579   /// actually used.
580   ///
581   int CreateVariableSizedObject(unsigned Alignment, const AllocaInst *Alloca);
582 
583   /// getCalleeSavedInfo - Returns a reference to call saved info vector for the
584   /// current function.
getCalleeSavedInfo()585   const std::vector<CalleeSavedInfo> &getCalleeSavedInfo() const {
586     return CSInfo;
587   }
588 
589   /// setCalleeSavedInfo - Used by prolog/epilog inserter to set the function's
590   /// callee saved information.
setCalleeSavedInfo(const std::vector<CalleeSavedInfo> & CSI)591   void setCalleeSavedInfo(const std::vector<CalleeSavedInfo> &CSI) {
592     CSInfo = CSI;
593   }
594 
595   /// isCalleeSavedInfoValid - Has the callee saved info been calculated yet?
isCalleeSavedInfoValid()596   bool isCalleeSavedInfoValid() const { return CSIValid; }
597 
setCalleeSavedInfoValid(bool v)598   void setCalleeSavedInfoValid(bool v) { CSIValid = v; }
599 
600   /// getPristineRegs - Return a set of physical registers that are pristine on
601   /// entry to the MBB.
602   ///
603   /// Pristine registers hold a value that is useless to the current function,
604   /// but that must be preserved - they are callee saved registers that have not
605   /// been saved yet.
606   ///
607   /// Before the PrologueEpilogueInserter has placed the CSR spill code, this
608   /// method always returns an empty set.
609   BitVector getPristineRegs(const MachineBasicBlock *MBB) const;
610 
611   /// print - Used by the MachineFunction printer to print information about
612   /// stack objects. Implemented in MachineFunction.cpp
613   ///
614   void print(const MachineFunction &MF, raw_ostream &OS) const;
615 
616   /// dump - Print the function to stderr.
617   void dump(const MachineFunction &MF) const;
618 };
619 
620 } // End llvm namespace
621 
622 #endif
623