1 //===-- CodeGen/MachineFrameInfo.h - Abstract Stack Frame Rep. --*- C++ -*-===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // The file defines the MachineFrameInfo class.
11 //===----------------------------------------------------------------------===//
13 #ifndef LLVM_CODEGEN_MACHINEFRAMEINFO_H
14 #define LLVM_CODEGEN_MACHINEFRAMEINFO_H
16 #include "llvm/ADT/SmallVector.h"
17 #include "llvm/Support/Alignment.h"
18 #include "llvm/Support/DataTypes.h"
24 class MachineFunction;
25 class MachineBasicBlock;
29 /// The CalleeSavedInfo class tracks the information need to locate where a
30 /// callee saved register is in the current frame.
31 /// Callee saved reg can also be saved to a different register rather than
32 /// on the stack by setting DstReg instead of FrameIdx.
33 class CalleeSavedInfo {
39 /// Flag indicating whether the register is actually restored in the epilog.
40 /// In most cases, if a register is saved, it is also restored. There are
41 /// some situations, though, when this is not the case. For example, the
42 /// LR register on ARM is usually saved, but on exit from the function its
43 /// saved value may be loaded directly into PC. Since liveness tracking of
44 /// physical registers treats callee-saved registers are live outside of
45 /// the function, LR would be treated as live-on-exit, even though in these
46 /// scenarios it is not. This flag is added to indicate that the saved
47 /// register described by this object is not restored in the epilog.
48 /// The long-term solution is to model the liveness of callee-saved registers
49 /// by implicit uses on the return instructions, however, the required
50 /// changes in the ARM backend would be quite extensive.
52 /// Flag indicating whether the register is spilled to stack or another
57 explicit CalleeSavedInfo(unsigned R, int FI = 0)
58 : Reg(R), FrameIdx(FI), Restored(true), SpilledToReg(false) {}
61 unsigned getReg() const { return Reg; }
62 int getFrameIdx() const { return FrameIdx; }
63 unsigned getDstReg() const { return DstReg; }
64 void setFrameIdx(int FI) {
68 void setDstReg(unsigned SpillReg) {
72 bool isRestored() const { return Restored; }
73 void setRestored(bool R) { Restored = R; }
74 bool isSpilledToReg() const { return SpilledToReg; }
77 /// The MachineFrameInfo class represents an abstract stack frame until
78 /// prolog/epilog code is inserted. This class is key to allowing stack frame
79 /// representation optimizations, such as frame pointer elimination. It also
80 /// allows more mundane (but still important) optimizations, such as reordering
81 /// of abstract objects on the stack frame.
83 /// To support this, the class assigns unique integer identifiers to stack
84 /// objects requested clients. These identifiers are negative integers for
85 /// fixed stack objects (such as arguments passed on the stack) or nonnegative
86 /// for objects that may be reordered. Instructions which refer to stack
87 /// objects use a special MO_FrameIndex operand to represent these frame
90 /// Because this class keeps track of all references to the stack frame, it
91 /// knows when a variable sized object is allocated on the stack. This is the
92 /// sole condition which prevents frame pointer elimination, which is an
93 /// important optimization on register-poor architectures. Because original
94 /// variable sized alloca's in the source program are the only source of
95 /// variable sized stack objects, it is safe to decide whether there will be
96 /// any variable sized objects before all stack objects are known (for
97 /// example, register allocator spill code never needs variable sized
100 /// When prolog/epilog code emission is performed, the final stack frame is
101 /// built and the machine instructions are modified to refer to the actual
102 /// stack offsets of the object, eliminating all MO_FrameIndex operands from
105 /// Abstract Stack Frame Information
106 class MachineFrameInfo {
108 /// Stack Smashing Protection (SSP) rules require that vulnerable stack
109 /// allocations are located close the stack protector.
111 SSPLK_None, ///< Did not trigger a stack protector. No effect on data
113 SSPLK_LargeArray, ///< Array or nested array >= SSP-buffer-size. Closest
114 ///< to the stack protector.
115 SSPLK_SmallArray, ///< Array or nested array < SSP-buffer-size. 2nd closest
116 ///< to the stack protector.
117 SSPLK_AddrOf ///< The address of this allocation is exposed and
118 ///< triggered protection. 3rd closest to the protector.
122 // Represent a single object allocated on the stack.
124 // The offset of this object from the stack pointer on entry to
125 // the function. This field has no meaning for a variable sized element.
128 // The size of this object on the stack. 0 means a variable sized object,
129 // ~0ULL means a dead object.
132 // The required alignment of this stack slot.
135 // If true, the value of the stack object is set before
136 // entering the function and is not modified inside the function. By
137 // default, fixed objects are immutable unless marked otherwise.
140 // If true the stack object is used as spill slot. It
141 // cannot alias any other memory objects.
144 /// If true, this stack slot is used to spill a value (could be deopt
145 /// and/or GC related) over a statepoint. We know that the address of the
146 /// slot can't alias any LLVM IR value. This is very similar to a Spill
147 /// Slot, but is created by statepoint lowering is SelectionDAG, not the
148 /// register allocator.
149 bool isStatepointSpillSlot = false;
151 /// Identifier for stack memory type analagous to address space. If this is
152 /// non-0, the meaning is target defined. Offsets cannot be directly
153 /// compared between objects with different stack IDs. The object may not
154 /// necessarily reside in the same contiguous memory block as other stack
155 /// objects. Objects with differing stack IDs should not be merged or
156 /// replaced substituted for each other.
158 /// It is assumed a target uses consecutive, increasing stack IDs starting
162 /// If this stack object is originated from an Alloca instruction
163 /// this value saves the original IR allocation. Can be NULL.
164 const AllocaInst *Alloca;
166 // If true, the object was mapped into the local frame
167 // block and doesn't need additional handling for allocation beyond that.
168 bool PreAllocated = false;
170 // If true, an LLVM IR value might point to this object.
171 // Normally, spill slots and fixed-offset objects don't alias IR-accessible
172 // objects, but there are exceptions (on PowerPC, for example, some byval
173 // arguments have ABI-prescribed offsets).
176 /// If true, the object has been zero-extended.
179 /// If true, the object has been zero-extended.
184 StackObject(uint64_t Size, Align Alignment, int64_t SPOffset,
185 bool IsImmutable, bool IsSpillSlot, const AllocaInst *Alloca,
186 bool IsAliased, uint8_t StackID = 0)
187 : SPOffset(SPOffset), Size(Size), Alignment(Alignment),
188 isImmutable(IsImmutable), isSpillSlot(IsSpillSlot), StackID(StackID),
189 Alloca(Alloca), isAliased(IsAliased), SSPLayout(SSPLK_None) {}
192 /// The alignment of the stack.
193 Align StackAlignment;
195 /// Can the stack be realigned. This can be false if the target does not
196 /// support stack realignment, or if the user asks us not to realign the
197 /// stack. In this situation, overaligned allocas are all treated as dynamic
198 /// allocations and the target must handle them as part of DYNAMIC_STACKALLOC
199 /// lowering. All non-alloca stack objects have their alignment clamped to the
200 /// base ABI stack alignment.
201 /// FIXME: There is room for improvement in this case, in terms of
202 /// grouping overaligned allocas into a "secondary stack frame" and
203 /// then only use a single alloca to allocate this frame and only a
204 /// single virtual register to access it. Currently, without such an
205 /// optimization, each such alloca gets its own dynamic realignment.
206 bool StackRealignable;
208 /// Whether the function has the \c alignstack attribute.
211 /// The list of stack objects allocated.
212 std::vector<StackObject> Objects;
214 /// This contains the number of fixed objects contained on
215 /// the stack. Because fixed objects are stored at a negative index in the
216 /// Objects list, this is also the index to the 0th object in the list.
217 unsigned NumFixedObjects = 0;
219 /// This boolean keeps track of whether any variable
220 /// sized objects have been allocated yet.
221 bool HasVarSizedObjects = false;
223 /// This boolean keeps track of whether there is a call
224 /// to builtin \@llvm.frameaddress.
225 bool FrameAddressTaken = false;
227 /// This boolean keeps track of whether there is a call
228 /// to builtin \@llvm.returnaddress.
229 bool ReturnAddressTaken = false;
231 /// This boolean keeps track of whether there is a call
232 /// to builtin \@llvm.experimental.stackmap.
233 bool HasStackMap = false;
235 /// This boolean keeps track of whether there is a call
236 /// to builtin \@llvm.experimental.patchpoint.
237 bool HasPatchPoint = false;
239 /// The prolog/epilog code inserter calculates the final stack
240 /// offsets for all of the fixed size objects, updating the Objects list
241 /// above. It then updates StackSize to contain the number of bytes that need
242 /// to be allocated on entry to the function.
243 uint64_t StackSize = 0;
245 /// The amount that a frame offset needs to be adjusted to
246 /// have the actual offset from the stack/frame pointer. The exact usage of
247 /// this is target-dependent, but it is typically used to adjust between
248 /// SP-relative and FP-relative offsets. E.G., if objects are accessed via
249 /// SP then OffsetAdjustment is zero; if FP is used, OffsetAdjustment is set
250 /// to the distance between the initial SP and the value in FP. For many
251 /// targets, this value is only used when generating debug info (via
252 /// TargetRegisterInfo::getFrameIndexReference); when generating code, the
253 /// corresponding adjustments are performed directly.
254 int OffsetAdjustment = 0;
256 /// The prolog/epilog code inserter may process objects that require greater
257 /// alignment than the default alignment the target provides.
258 /// To handle this, MaxAlignment is set to the maximum alignment
259 /// needed by the objects on the current frame. If this is greater than the
260 /// native alignment maintained by the compiler, dynamic alignment code will
265 /// Set to true if this function adjusts the stack -- e.g.,
266 /// when calling another function. This is only valid during and after
267 /// prolog/epilog code insertion.
268 bool AdjustsStack = false;
270 /// Set to true if this function has any function calls.
271 bool HasCalls = false;
273 /// The frame index for the stack protector.
274 int StackProtectorIdx = -1;
276 /// The frame index for the function context. Used for SjLj exceptions.
277 int FunctionContextIdx = -1;
279 /// This contains the size of the largest call frame if the target uses frame
280 /// setup/destroy pseudo instructions (as defined in the TargetFrameInfo
281 /// class). This information is important for frame pointer elimination.
282 /// It is only valid during and after prolog/epilog code insertion.
283 unsigned MaxCallFrameSize = ~0u;
285 /// The number of bytes of callee saved registers that the target wants to
286 /// report for the current function in the CodeView S_FRAMEPROC record.
287 unsigned CVBytesOfCalleeSavedRegisters = 0;
289 /// The prolog/epilog code inserter fills in this vector with each
290 /// callee saved register saved in either the frame or a different
291 /// register. Beyond its use by the prolog/ epilog code inserter,
292 /// this data is used for debug info and exception handling.
293 std::vector<CalleeSavedInfo> CSInfo;
295 /// Has CSInfo been set yet?
296 bool CSIValid = false;
298 /// References to frame indices which are mapped
299 /// into the local frame allocation block. <FrameIdx, LocalOffset>
300 SmallVector<std::pair<int, int64_t>, 32> LocalFrameObjects;
302 /// Size of the pre-allocated local frame block.
303 int64_t LocalFrameSize = 0;
305 /// Required alignment of the local object blob, which is the strictest
306 /// alignment of any object in it.
307 Align LocalFrameMaxAlign;
309 /// Whether the local object blob needs to be allocated together. If not,
310 /// PEI should ignore the isPreAllocated flags on the stack objects and
311 /// just allocate them normally.
312 bool UseLocalStackAllocationBlock = false;
314 /// True if the function dynamically adjusts the stack pointer through some
315 /// opaque mechanism like inline assembly or Win32 EH.
316 bool HasOpaqueSPAdjustment = false;
318 /// True if the function contains operations which will lower down to
319 /// instructions which manipulate the stack pointer.
320 bool HasCopyImplyingStackAdjustment = false;
322 /// True if the function contains a call to the llvm.vastart intrinsic.
323 bool HasVAStart = false;
325 /// True if this is a varargs function that contains a musttail call.
326 bool HasMustTailInVarArgFunc = false;
328 /// True if this function contains a tail call. If so immutable objects like
329 /// function arguments are no longer so. A tail call *can* override fixed
330 /// stack objects like arguments so we can't treat them as immutable.
331 bool HasTailCall = false;
333 /// Not null, if shrink-wrapping found a better place for the prologue.
334 MachineBasicBlock *Save = nullptr;
335 /// Not null, if shrink-wrapping found a better place for the epilogue.
336 MachineBasicBlock *Restore = nullptr;
339 explicit MachineFrameInfo(unsigned StackAlignment, bool StackRealignable,
341 : StackAlignment(assumeAligned(StackAlignment)),
342 StackRealignable(StackRealignable), ForcedRealign(ForcedRealign) {}
344 /// Return true if there are any stack objects in this function.
345 bool hasStackObjects() const { return !Objects.empty(); }
347 /// This method may be called any time after instruction
348 /// selection is complete to determine if the stack frame for this function
349 /// contains any variable sized objects.
350 bool hasVarSizedObjects() const { return HasVarSizedObjects; }
352 /// Return the index for the stack protector object.
353 int getStackProtectorIndex() const { return StackProtectorIdx; }
354 void setStackProtectorIndex(int I) { StackProtectorIdx = I; }
355 bool hasStackProtectorIndex() const { return StackProtectorIdx != -1; }
357 /// Return the index for the function context object.
358 /// This object is used for SjLj exceptions.
359 int getFunctionContextIndex() const { return FunctionContextIdx; }
360 void setFunctionContextIndex(int I) { FunctionContextIdx = I; }
362 /// This method may be called any time after instruction
363 /// selection is complete to determine if there is a call to
364 /// \@llvm.frameaddress in this function.
365 bool isFrameAddressTaken() const { return FrameAddressTaken; }
366 void setFrameAddressIsTaken(bool T) { FrameAddressTaken = T; }
368 /// This method may be called any time after
369 /// instruction selection is complete to determine if there is a call to
370 /// \@llvm.returnaddress in this function.
371 bool isReturnAddressTaken() const { return ReturnAddressTaken; }
372 void setReturnAddressIsTaken(bool s) { ReturnAddressTaken = s; }
374 /// This method may be called any time after instruction
375 /// selection is complete to determine if there is a call to builtin
376 /// \@llvm.experimental.stackmap.
377 bool hasStackMap() const { return HasStackMap; }
378 void setHasStackMap(bool s = true) { HasStackMap = s; }
380 /// This method may be called any time after instruction
381 /// selection is complete to determine if there is a call to builtin
382 /// \@llvm.experimental.patchpoint.
383 bool hasPatchPoint() const { return HasPatchPoint; }
384 void setHasPatchPoint(bool s = true) { HasPatchPoint = s; }
386 /// Return the minimum frame object index.
387 int getObjectIndexBegin() const { return -NumFixedObjects; }
389 /// Return one past the maximum frame object index.
390 int getObjectIndexEnd() const { return (int)Objects.size()-NumFixedObjects; }
392 /// Return the number of fixed objects.
393 unsigned getNumFixedObjects() const { return NumFixedObjects; }
395 /// Return the number of objects.
396 unsigned getNumObjects() const { return Objects.size(); }
398 /// Map a frame index into the local object block
399 void mapLocalFrameObject(int ObjectIndex, int64_t Offset) {
400 LocalFrameObjects.push_back(std::pair<int, int64_t>(ObjectIndex, Offset));
401 Objects[ObjectIndex + NumFixedObjects].PreAllocated = true;
404 /// Get the local offset mapping for a for an object.
405 std::pair<int, int64_t> getLocalFrameObjectMap(int i) const {
406 assert (i >= 0 && (unsigned)i < LocalFrameObjects.size() &&
407 "Invalid local object reference!");
408 return LocalFrameObjects[i];
411 /// Return the number of objects allocated into the local object block.
412 int64_t getLocalFrameObjectCount() const { return LocalFrameObjects.size(); }
414 /// Set the size of the local object blob.
415 void setLocalFrameSize(int64_t sz) { LocalFrameSize = sz; }
417 /// Get the size of the local object blob.
418 int64_t getLocalFrameSize() const { return LocalFrameSize; }
420 /// Required alignment of the local object blob,
421 /// which is the strictest alignment of any object in it.
422 void setLocalFrameMaxAlign(Align Alignment) {
423 LocalFrameMaxAlign = Alignment;
426 /// Return the required alignment of the local object blob.
427 Align getLocalFrameMaxAlign() const { return LocalFrameMaxAlign; }
429 /// Get whether the local allocation blob should be allocated together or
430 /// let PEI allocate the locals in it directly.
431 bool getUseLocalStackAllocationBlock() const {
432 return UseLocalStackAllocationBlock;
435 /// setUseLocalStackAllocationBlock - Set whether the local allocation blob
436 /// should be allocated together or let PEI allocate the locals in it
438 void setUseLocalStackAllocationBlock(bool v) {
439 UseLocalStackAllocationBlock = v;
442 /// Return true if the object was pre-allocated into the local block.
443 bool isObjectPreAllocated(int ObjectIdx) const {
444 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
445 "Invalid Object Idx!");
446 return Objects[ObjectIdx+NumFixedObjects].PreAllocated;
449 /// Return the size of the specified object.
450 int64_t getObjectSize(int ObjectIdx) const {
451 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
452 "Invalid Object Idx!");
453 return Objects[ObjectIdx+NumFixedObjects].Size;
456 /// Change the size of the specified stack object.
457 void setObjectSize(int ObjectIdx, int64_t Size) {
458 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
459 "Invalid Object Idx!");
460 Objects[ObjectIdx+NumFixedObjects].Size = Size;
463 LLVM_ATTRIBUTE_DEPRECATED(inline unsigned getObjectAlignment(int ObjectIdx)
465 "Use getObjectAlign instead") {
466 return getObjectAlign(ObjectIdx).value();
469 /// Return the alignment of the specified stack object.
470 Align getObjectAlign(int ObjectIdx) const {
471 assert(unsigned(ObjectIdx + NumFixedObjects) < Objects.size() &&
472 "Invalid Object Idx!");
473 return Objects[ObjectIdx + NumFixedObjects].Alignment;
476 /// setObjectAlignment - Change the alignment of the specified stack object.
477 void setObjectAlignment(int ObjectIdx, Align Alignment) {
478 assert(unsigned(ObjectIdx + NumFixedObjects) < Objects.size() &&
479 "Invalid Object Idx!");
480 Objects[ObjectIdx + NumFixedObjects].Alignment = Alignment;
482 // Only ensure max alignment for the default stack.
483 if (getStackID(ObjectIdx) == 0)
484 ensureMaxAlignment(Alignment);
487 LLVM_ATTRIBUTE_DEPRECATED(inline void setObjectAlignment(int ObjectIdx,
489 "Use the version that takes Align instead") {
490 setObjectAlignment(ObjectIdx, assumeAligned(Align));
493 /// Return the underlying Alloca of the specified
494 /// stack object if it exists. Returns 0 if none exists.
495 const AllocaInst* getObjectAllocation(int ObjectIdx) const {
496 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
497 "Invalid Object Idx!");
498 return Objects[ObjectIdx+NumFixedObjects].Alloca;
501 /// Return the assigned stack offset of the specified object
502 /// from the incoming stack pointer.
503 int64_t getObjectOffset(int ObjectIdx) const {
504 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
505 "Invalid Object Idx!");
506 assert(!isDeadObjectIndex(ObjectIdx) &&
507 "Getting frame offset for a dead object?");
508 return Objects[ObjectIdx+NumFixedObjects].SPOffset;
511 bool isObjectZExt(int ObjectIdx) const {
512 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
513 "Invalid Object Idx!");
514 return Objects[ObjectIdx+NumFixedObjects].isZExt;
517 void setObjectZExt(int ObjectIdx, bool IsZExt) {
518 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
519 "Invalid Object Idx!");
520 Objects[ObjectIdx+NumFixedObjects].isZExt = IsZExt;
523 bool isObjectSExt(int ObjectIdx) const {
524 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
525 "Invalid Object Idx!");
526 return Objects[ObjectIdx+NumFixedObjects].isSExt;
529 void setObjectSExt(int ObjectIdx, bool IsSExt) {
530 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
531 "Invalid Object Idx!");
532 Objects[ObjectIdx+NumFixedObjects].isSExt = IsSExt;
535 /// Set the stack frame offset of the specified object. The
536 /// offset is relative to the stack pointer on entry to the function.
537 void setObjectOffset(int ObjectIdx, int64_t SPOffset) {
538 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
539 "Invalid Object Idx!");
540 assert(!isDeadObjectIndex(ObjectIdx) &&
541 "Setting frame offset for a dead object?");
542 Objects[ObjectIdx+NumFixedObjects].SPOffset = SPOffset;
545 SSPLayoutKind getObjectSSPLayout(int ObjectIdx) const {
546 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
547 "Invalid Object Idx!");
548 return (SSPLayoutKind)Objects[ObjectIdx+NumFixedObjects].SSPLayout;
551 void setObjectSSPLayout(int ObjectIdx, SSPLayoutKind Kind) {
552 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
553 "Invalid Object Idx!");
554 assert(!isDeadObjectIndex(ObjectIdx) &&
555 "Setting SSP layout for a dead object?");
556 Objects[ObjectIdx+NumFixedObjects].SSPLayout = Kind;
559 /// Return the number of bytes that must be allocated to hold
560 /// all of the fixed size frame objects. This is only valid after
561 /// Prolog/Epilog code insertion has finalized the stack frame layout.
562 uint64_t getStackSize() const { return StackSize; }
564 /// Set the size of the stack.
565 void setStackSize(uint64_t Size) { StackSize = Size; }
567 /// Estimate and return the size of the stack frame.
568 uint64_t estimateStackSize(const MachineFunction &MF) const;
570 /// Return the correction for frame offsets.
571 int getOffsetAdjustment() const { return OffsetAdjustment; }
573 /// Set the correction for frame offsets.
574 void setOffsetAdjustment(int Adj) { OffsetAdjustment = Adj; }
576 /// Return the alignment in bytes that this function must be aligned to,
577 /// which is greater than the default stack alignment provided by the target.
578 LLVM_ATTRIBUTE_DEPRECATED(unsigned getMaxAlignment() const,
579 "Use getMaxAlign instead") {
580 return MaxAlignment.value();
582 /// Return the alignment in bytes that this function must be aligned to,
583 /// which is greater than the default stack alignment provided by the target.
584 Align getMaxAlign() const { return MaxAlignment; }
586 /// Make sure the function is at least Align bytes aligned.
587 void ensureMaxAlignment(Align Alignment);
589 LLVM_ATTRIBUTE_DEPRECATED(inline void ensureMaxAlignment(unsigned Align),
590 "Use the version that uses Align instead") {
591 ensureMaxAlignment(assumeAligned(Align));
594 /// Return true if this function adjusts the stack -- e.g.,
595 /// when calling another function. This is only valid during and after
596 /// prolog/epilog code insertion.
597 bool adjustsStack() const { return AdjustsStack; }
598 void setAdjustsStack(bool V) { AdjustsStack = V; }
600 /// Return true if the current function has any function calls.
601 bool hasCalls() const { return HasCalls; }
602 void setHasCalls(bool V) { HasCalls = V; }
604 /// Returns true if the function contains opaque dynamic stack adjustments.
605 bool hasOpaqueSPAdjustment() const { return HasOpaqueSPAdjustment; }
606 void setHasOpaqueSPAdjustment(bool B) { HasOpaqueSPAdjustment = B; }
608 /// Returns true if the function contains operations which will lower down to
609 /// instructions which manipulate the stack pointer.
610 bool hasCopyImplyingStackAdjustment() const {
611 return HasCopyImplyingStackAdjustment;
613 void setHasCopyImplyingStackAdjustment(bool B) {
614 HasCopyImplyingStackAdjustment = B;
617 /// Returns true if the function calls the llvm.va_start intrinsic.
618 bool hasVAStart() const { return HasVAStart; }
619 void setHasVAStart(bool B) { HasVAStart = B; }
621 /// Returns true if the function is variadic and contains a musttail call.
622 bool hasMustTailInVarArgFunc() const { return HasMustTailInVarArgFunc; }
623 void setHasMustTailInVarArgFunc(bool B) { HasMustTailInVarArgFunc = B; }
625 /// Returns true if the function contains a tail call.
626 bool hasTailCall() const { return HasTailCall; }
627 void setHasTailCall() { HasTailCall = true; }
629 /// Computes the maximum size of a callframe and the AdjustsStack property.
630 /// This only works for targets defining
631 /// TargetInstrInfo::getCallFrameSetupOpcode(), getCallFrameDestroyOpcode(),
632 /// and getFrameSize().
633 /// This is usually computed by the prologue epilogue inserter but some
634 /// targets may call this to compute it earlier.
635 void computeMaxCallFrameSize(const MachineFunction &MF);
637 /// Return the maximum size of a call frame that must be
638 /// allocated for an outgoing function call. This is only available if
639 /// CallFrameSetup/Destroy pseudo instructions are used by the target, and
640 /// then only during or after prolog/epilog code insertion.
642 unsigned getMaxCallFrameSize() const {
643 // TODO: Enable this assert when targets are fixed.
644 //assert(isMaxCallFrameSizeComputed() && "MaxCallFrameSize not computed yet");
645 if (!isMaxCallFrameSizeComputed())
647 return MaxCallFrameSize;
649 bool isMaxCallFrameSizeComputed() const {
650 return MaxCallFrameSize != ~0u;
652 void setMaxCallFrameSize(unsigned S) { MaxCallFrameSize = S; }
654 /// Returns how many bytes of callee-saved registers the target pushed in the
655 /// prologue. Only used for debug info.
656 unsigned getCVBytesOfCalleeSavedRegisters() const {
657 return CVBytesOfCalleeSavedRegisters;
659 void setCVBytesOfCalleeSavedRegisters(unsigned S) {
660 CVBytesOfCalleeSavedRegisters = S;
663 /// Create a new object at a fixed location on the stack.
664 /// All fixed objects should be created before other objects are created for
665 /// efficiency. By default, fixed objects are not pointed to by LLVM IR
666 /// values. This returns an index with a negative value.
667 int CreateFixedObject(uint64_t Size, int64_t SPOffset, bool IsImmutable,
668 bool isAliased = false);
670 /// Create a spill slot at a fixed location on the stack.
671 /// Returns an index with a negative value.
672 int CreateFixedSpillStackObject(uint64_t Size, int64_t SPOffset,
673 bool IsImmutable = false);
675 /// Returns true if the specified index corresponds to a fixed stack object.
676 bool isFixedObjectIndex(int ObjectIdx) const {
677 return ObjectIdx < 0 && (ObjectIdx >= -(int)NumFixedObjects);
680 /// Returns true if the specified index corresponds
681 /// to an object that might be pointed to by an LLVM IR value.
682 bool isAliasedObjectIndex(int ObjectIdx) const {
683 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
684 "Invalid Object Idx!");
685 return Objects[ObjectIdx+NumFixedObjects].isAliased;
688 /// Returns true if the specified index corresponds to an immutable object.
689 bool isImmutableObjectIndex(int ObjectIdx) const {
690 // Tail calling functions can clobber their function arguments.
693 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
694 "Invalid Object Idx!");
695 return Objects[ObjectIdx+NumFixedObjects].isImmutable;
698 /// Marks the immutability of an object.
699 void setIsImmutableObjectIndex(int ObjectIdx, bool IsImmutable) {
700 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
701 "Invalid Object Idx!");
702 Objects[ObjectIdx+NumFixedObjects].isImmutable = IsImmutable;
705 /// Returns true if the specified index corresponds to a spill slot.
706 bool isSpillSlotObjectIndex(int ObjectIdx) const {
707 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
708 "Invalid Object Idx!");
709 return Objects[ObjectIdx+NumFixedObjects].isSpillSlot;
712 bool isStatepointSpillSlotObjectIndex(int ObjectIdx) const {
713 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
714 "Invalid Object Idx!");
715 return Objects[ObjectIdx+NumFixedObjects].isStatepointSpillSlot;
719 uint8_t getStackID(int ObjectIdx) const {
720 return Objects[ObjectIdx+NumFixedObjects].StackID;
724 void setStackID(int ObjectIdx, uint8_t ID) {
725 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
726 "Invalid Object Idx!");
727 Objects[ObjectIdx+NumFixedObjects].StackID = ID;
728 // If ID > 0, MaxAlignment may now be overly conservative.
729 // If ID == 0, MaxAlignment will need to be updated separately.
732 /// Returns true if the specified index corresponds to a dead object.
733 bool isDeadObjectIndex(int ObjectIdx) const {
734 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
735 "Invalid Object Idx!");
736 return Objects[ObjectIdx+NumFixedObjects].Size == ~0ULL;
739 /// Returns true if the specified index corresponds to a variable sized
741 bool isVariableSizedObjectIndex(int ObjectIdx) const {
742 assert(unsigned(ObjectIdx + NumFixedObjects) < Objects.size() &&
743 "Invalid Object Idx!");
744 return Objects[ObjectIdx + NumFixedObjects].Size == 0;
747 void markAsStatepointSpillSlotObjectIndex(int ObjectIdx) {
748 assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
749 "Invalid Object Idx!");
750 Objects[ObjectIdx+NumFixedObjects].isStatepointSpillSlot = true;
751 assert(isStatepointSpillSlotObjectIndex(ObjectIdx) && "inconsistent");
754 /// Create a new statically sized stack object, returning
755 /// a nonnegative identifier to represent it.
756 int CreateStackObject(uint64_t Size, Align Alignment, bool isSpillSlot,
757 const AllocaInst *Alloca = nullptr, uint8_t ID = 0);
758 LLVM_ATTRIBUTE_DEPRECATED(
759 inline int CreateStackObject(uint64_t Size, unsigned Alignment,
761 const AllocaInst *Alloca = nullptr,
763 "Use CreateStackObject that takes an Align instead") {
764 return CreateStackObject(Size, assumeAligned(Alignment), isSpillSlot,
768 /// Create a new statically sized stack object that represents a spill slot,
769 /// returning a nonnegative identifier to represent it.
770 int CreateSpillStackObject(uint64_t Size, Align Alignment);
771 LLVM_ATTRIBUTE_DEPRECATED(
772 inline int CreateSpillStackObject(uint64_t Size, unsigned Alignment),
773 "Use CreateSpillStackObject that takes an Align instead") {
774 return CreateSpillStackObject(Size, assumeAligned(Alignment));
777 /// Remove or mark dead a statically sized stack object.
778 void RemoveStackObject(int ObjectIdx) {
780 Objects[ObjectIdx+NumFixedObjects].Size = ~0ULL;
783 /// Notify the MachineFrameInfo object that a variable sized object has been
784 /// created. This must be created whenever a variable sized object is
785 /// created, whether or not the index returned is actually used.
786 int CreateVariableSizedObject(Align Alignment, const AllocaInst *Alloca);
787 /// FIXME: Remove this function when transition to Align is over.
788 LLVM_ATTRIBUTE_DEPRECATED(int CreateVariableSizedObject(
789 unsigned Alignment, const AllocaInst *Alloca),
790 "Use the version that takes an Align instead") {
791 return CreateVariableSizedObject(assumeAligned(Alignment), Alloca);
794 /// Returns a reference to call saved info vector for the current function.
795 const std::vector<CalleeSavedInfo> &getCalleeSavedInfo() const {
798 /// \copydoc getCalleeSavedInfo()
799 std::vector<CalleeSavedInfo> &getCalleeSavedInfo() { return CSInfo; }
801 /// Used by prolog/epilog inserter to set the function's callee saved
803 void setCalleeSavedInfo(std::vector<CalleeSavedInfo> CSI) {
804 CSInfo = std::move(CSI);
807 /// Has the callee saved info been calculated yet?
808 bool isCalleeSavedInfoValid() const { return CSIValid; }
810 void setCalleeSavedInfoValid(bool v) { CSIValid = v; }
812 MachineBasicBlock *getSavePoint() const { return Save; }
813 void setSavePoint(MachineBasicBlock *NewSave) { Save = NewSave; }
814 MachineBasicBlock *getRestorePoint() const { return Restore; }
815 void setRestorePoint(MachineBasicBlock *NewRestore) { Restore = NewRestore; }
817 /// Return a set of physical registers that are pristine.
819 /// Pristine registers hold a value that is useless to the current function,
820 /// but that must be preserved - they are callee saved registers that are not
823 /// Before the PrologueEpilogueInserter has placed the CSR spill code, this
824 /// method always returns an empty set.
825 BitVector getPristineRegs(const MachineFunction &MF) const;
827 /// Used by the MachineFunction printer to print information about
828 /// stack objects. Implemented in MachineFunction.cpp.
829 void print(const MachineFunction &MF, raw_ostream &OS) const;
831 /// dump - Print the function to stderr.
832 void dump(const MachineFunction &MF) const;
835 } // End llvm namespace