1//=- AArch64MachineFunctionInfo.h - AArch64 machine function info -*- C++ -*-=//
2//
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
6//
7//===----------------------------------------------------------------------===//
8//
9// This file declares AArch64-specific per-machine-function information.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_LIB_TARGET_AARCH64_AARCH64MACHINEFUNCTIONINFO_H
14#define LLVM_LIB_TARGET_AARCH64_AARCH64MACHINEFUNCTIONINFO_H
15
16#include "llvm/ADT/ArrayRef.h"
17#include "llvm/ADT/Optional.h"
18#include "llvm/ADT/SmallPtrSet.h"
19#include "llvm/ADT/SmallVector.h"
20#include "llvm/CodeGen/CallingConvLower.h"
21#include "llvm/CodeGen/MachineFunction.h"
22#include "llvm/CodeGen/TargetFrameLowering.h"
23#include "llvm/IR/Function.h"
24#include "llvm/MC/MCLinkerOptimizationHint.h"
25#include <cassert>
26
27namespace llvm {
28
29class MachineInstr;
30
31/// AArch64FunctionInfo - This class is derived from MachineFunctionInfo and
32/// contains private AArch64-specific information for each MachineFunction.
33class AArch64FunctionInfo final : public MachineFunctionInfo {
34  /// Number of bytes of arguments this function has on the stack. If the callee
35  /// is expected to restore the argument stack this should be a multiple of 16,
36  /// all usable during a tail call.
37  ///
38  /// The alternative would forbid tail call optimisation in some cases: if we
39  /// want to transfer control from a function with 8-bytes of stack-argument
40  /// space to a function with 16-bytes then misalignment of this value would
41  /// make a stack adjustment necessary, which could not be undone by the
42  /// callee.
43  unsigned BytesInStackArgArea = 0;
44
45  /// The number of bytes to restore to deallocate space for incoming
46  /// arguments. Canonically 0 in the C calling convention, but non-zero when
47  /// callee is expected to pop the args.
48  unsigned ArgumentStackToRestore = 0;
49
50  /// HasStackFrame - True if this function has a stack frame. Set by
51  /// determineCalleeSaves().
52  bool HasStackFrame = false;
53
54  /// Amount of stack frame size, not including callee-saved registers.
55  uint64_t LocalStackSize = 0;
56
57  /// The start and end frame indices for the SVE callee saves.
58  int MinSVECSFrameIndex = 0;
59  int MaxSVECSFrameIndex = 0;
60
61  /// Amount of stack frame size used for saving callee-saved registers.
62  unsigned CalleeSavedStackSize = 0;
63  unsigned SVECalleeSavedStackSize = 0;
64  bool HasCalleeSavedStackSize = false;
65
66  /// Number of TLS accesses using the special (combinable)
67  /// _TLS_MODULE_BASE_ symbol.
68  unsigned NumLocalDynamicTLSAccesses = 0;
69
70  /// FrameIndex for start of varargs area for arguments passed on the
71  /// stack.
72  int VarArgsStackIndex = 0;
73
74  /// FrameIndex for start of varargs area for arguments passed in
75  /// general purpose registers.
76  int VarArgsGPRIndex = 0;
77
78  /// Size of the varargs area for arguments passed in general purpose
79  /// registers.
80  unsigned VarArgsGPRSize = 0;
81
82  /// FrameIndex for start of varargs area for arguments passed in
83  /// floating-point registers.
84  int VarArgsFPRIndex = 0;
85
86  /// Size of the varargs area for arguments passed in floating-point
87  /// registers.
88  unsigned VarArgsFPRSize = 0;
89
90  /// True if this function has a subset of CSRs that is handled explicitly via
91  /// copies.
92  bool IsSplitCSR = false;
93
94  /// True when the stack gets realigned dynamically because the size of stack
95  /// frame is unknown at compile time. e.g., in case of VLAs.
96  bool StackRealigned = false;
97
98  /// True when the callee-save stack area has unused gaps that may be used for
99  /// other stack allocations.
100  bool CalleeSaveStackHasFreeSpace = false;
101
102  /// SRetReturnReg - sret lowering includes returning the value of the
103  /// returned struct in a register. This field holds the virtual register into
104  /// which the sret argument is passed.
105  unsigned SRetReturnReg = 0;
106  /// SVE stack size (for predicates and data vectors) are maintained here
107  /// rather than in FrameInfo, as the placement and Stack IDs are target
108  /// specific.
109  uint64_t StackSizeSVE = 0;
110
111  /// HasCalculatedStackSizeSVE indicates whether StackSizeSVE is valid.
112  bool HasCalculatedStackSizeSVE = false;
113
114  /// Has a value when it is known whether or not the function uses a
115  /// redzone, and no value otherwise.
116  /// Initialized during frame lowering, unless the function has the noredzone
117  /// attribute, in which case it is set to false at construction.
118  Optional<bool> HasRedZone;
119
120  /// ForwardedMustTailRegParms - A list of virtual and physical registers
121  /// that must be forwarded to every musttail call.
122  SmallVector<ForwardedRegister, 1> ForwardedMustTailRegParms;
123
124  // Offset from SP-at-entry to the tagged base pointer.
125  // Tagged base pointer is set up to point to the first (lowest address) tagged
126  // stack slot.
127  unsigned TaggedBasePointerOffset = 0;
128
129public:
130  AArch64FunctionInfo() = default;
131
132  explicit AArch64FunctionInfo(MachineFunction &MF) {
133    (void)MF;
134
135    // If we already know that the function doesn't have a redzone, set
136    // HasRedZone here.
137    if (MF.getFunction().hasFnAttribute(Attribute::NoRedZone))
138      HasRedZone = false;
139  }
140
141  unsigned getBytesInStackArgArea() const { return BytesInStackArgArea; }
142  void setBytesInStackArgArea(unsigned bytes) { BytesInStackArgArea = bytes; }
143
144  unsigned getArgumentStackToRestore() const { return ArgumentStackToRestore; }
145  void setArgumentStackToRestore(unsigned bytes) {
146    ArgumentStackToRestore = bytes;
147  }
148
149  bool hasCalculatedStackSizeSVE() const { return HasCalculatedStackSizeSVE; }
150
151  void setStackSizeSVE(uint64_t S) {
152    HasCalculatedStackSizeSVE = true;
153    StackSizeSVE = S;
154  }
155
156  uint64_t getStackSizeSVE() const { return StackSizeSVE; }
157
158  bool hasStackFrame() const { return HasStackFrame; }
159  void setHasStackFrame(bool s) { HasStackFrame = s; }
160
161  bool isStackRealigned() const { return StackRealigned; }
162  void setStackRealigned(bool s) { StackRealigned = s; }
163
164  bool hasCalleeSaveStackFreeSpace() const {
165    return CalleeSaveStackHasFreeSpace;
166  }
167  void setCalleeSaveStackHasFreeSpace(bool s) {
168    CalleeSaveStackHasFreeSpace = s;
169  }
170  bool isSplitCSR() const { return IsSplitCSR; }
171  void setIsSplitCSR(bool s) { IsSplitCSR = s; }
172
173  void setLocalStackSize(uint64_t Size) { LocalStackSize = Size; }
174  uint64_t getLocalStackSize() const { return LocalStackSize; }
175
176  void setCalleeSavedStackSize(unsigned Size) {
177    CalleeSavedStackSize = Size;
178    HasCalleeSavedStackSize = true;
179  }
180
181  // When CalleeSavedStackSize has not been set (for example when
182  // some MachineIR pass is run in isolation), then recalculate
183  // the CalleeSavedStackSize directly from the CalleeSavedInfo.
184  // Note: This information can only be recalculated after PEI
185  // has assigned offsets to the callee save objects.
186  unsigned getCalleeSavedStackSize(const MachineFrameInfo &MFI) const {
187    bool ValidateCalleeSavedStackSize = false;
188
189#ifndef NDEBUG
190    // Make sure the calculated size derived from the CalleeSavedInfo
191    // equals the cached size that was calculated elsewhere (e.g. in
192    // determineCalleeSaves).
193    ValidateCalleeSavedStackSize = HasCalleeSavedStackSize;
194#endif
195
196    if (!HasCalleeSavedStackSize || ValidateCalleeSavedStackSize) {
197      assert(MFI.isCalleeSavedInfoValid() && "CalleeSavedInfo not calculated");
198      if (MFI.getCalleeSavedInfo().empty())
199        return 0;
200
201      int64_t MinOffset = std::numeric_limits<int64_t>::max();
202      int64_t MaxOffset = std::numeric_limits<int64_t>::min();
203      for (const auto &Info : MFI.getCalleeSavedInfo()) {
204        int FrameIdx = Info.getFrameIdx();
205        if (MFI.getStackID(FrameIdx) != TargetStackID::Default)
206          continue;
207        int64_t Offset = MFI.getObjectOffset(FrameIdx);
208        int64_t ObjSize = MFI.getObjectSize(FrameIdx);
209        MinOffset = std::min<int64_t>(Offset, MinOffset);
210        MaxOffset = std::max<int64_t>(Offset + ObjSize, MaxOffset);
211      }
212
213      unsigned Size = alignTo(MaxOffset - MinOffset, 16);
214      assert((!HasCalleeSavedStackSize || getCalleeSavedStackSize() == Size) &&
215             "Invalid size calculated for callee saves");
216      return Size;
217    }
218
219    return getCalleeSavedStackSize();
220  }
221
222  unsigned getCalleeSavedStackSize() const {
223    assert(HasCalleeSavedStackSize &&
224           "CalleeSavedStackSize has not been calculated");
225    return CalleeSavedStackSize;
226  }
227
228  // Saves the CalleeSavedStackSize for SVE vectors in 'scalable bytes'
229  void setSVECalleeSavedStackSize(unsigned Size) {
230    SVECalleeSavedStackSize = Size;
231  }
232  unsigned getSVECalleeSavedStackSize() const {
233    return SVECalleeSavedStackSize;
234  }
235
236  void setMinMaxSVECSFrameIndex(int Min, int Max) {
237    MinSVECSFrameIndex = Min;
238    MaxSVECSFrameIndex = Max;
239  }
240
241  int getMinSVECSFrameIndex() const { return MinSVECSFrameIndex; }
242  int getMaxSVECSFrameIndex() const { return MaxSVECSFrameIndex; }
243
244  void incNumLocalDynamicTLSAccesses() { ++NumLocalDynamicTLSAccesses; }
245  unsigned getNumLocalDynamicTLSAccesses() const {
246    return NumLocalDynamicTLSAccesses;
247  }
248
249  Optional<bool> hasRedZone() const { return HasRedZone; }
250  void setHasRedZone(bool s) { HasRedZone = s; }
251
252  int getVarArgsStackIndex() const { return VarArgsStackIndex; }
253  void setVarArgsStackIndex(int Index) { VarArgsStackIndex = Index; }
254
255  int getVarArgsGPRIndex() const { return VarArgsGPRIndex; }
256  void setVarArgsGPRIndex(int Index) { VarArgsGPRIndex = Index; }
257
258  unsigned getVarArgsGPRSize() const { return VarArgsGPRSize; }
259  void setVarArgsGPRSize(unsigned Size) { VarArgsGPRSize = Size; }
260
261  int getVarArgsFPRIndex() const { return VarArgsFPRIndex; }
262  void setVarArgsFPRIndex(int Index) { VarArgsFPRIndex = Index; }
263
264  unsigned getVarArgsFPRSize() const { return VarArgsFPRSize; }
265  void setVarArgsFPRSize(unsigned Size) { VarArgsFPRSize = Size; }
266
267  unsigned getSRetReturnReg() const { return SRetReturnReg; }
268  void setSRetReturnReg(unsigned Reg) { SRetReturnReg = Reg; }
269
270  unsigned getJumpTableEntrySize(int Idx) const {
271    auto It = JumpTableEntryInfo.find(Idx);
272    if (It != JumpTableEntryInfo.end())
273      return It->second.first;
274    return 4;
275  }
276  MCSymbol *getJumpTableEntryPCRelSymbol(int Idx) const {
277    return JumpTableEntryInfo.find(Idx)->second.second;
278  }
279  void setJumpTableEntryInfo(int Idx, unsigned Size, MCSymbol *PCRelSym) {
280    JumpTableEntryInfo[Idx] = std::make_pair(Size, PCRelSym);
281  }
282
283  using SetOfInstructions = SmallPtrSet<const MachineInstr *, 16>;
284
285  const SetOfInstructions &getLOHRelated() const { return LOHRelated; }
286
287  // Shortcuts for LOH related types.
288  class MILOHDirective {
289    MCLOHType Kind;
290
291    /// Arguments of this directive. Order matters.
292    SmallVector<const MachineInstr *, 3> Args;
293
294  public:
295    using LOHArgs = ArrayRef<const MachineInstr *>;
296
297    MILOHDirective(MCLOHType Kind, LOHArgs Args)
298        : Kind(Kind), Args(Args.begin(), Args.end()) {
299      assert(isValidMCLOHType(Kind) && "Invalid LOH directive type!");
300    }
301
302    MCLOHType getKind() const { return Kind; }
303    LOHArgs getArgs() const { return Args; }
304  };
305
306  using MILOHArgs = MILOHDirective::LOHArgs;
307  using MILOHContainer = SmallVector<MILOHDirective, 32>;
308
309  const MILOHContainer &getLOHContainer() const { return LOHContainerSet; }
310
311  /// Add a LOH directive of this @p Kind and this @p Args.
312  void addLOHDirective(MCLOHType Kind, MILOHArgs Args) {
313    LOHContainerSet.push_back(MILOHDirective(Kind, Args));
314    LOHRelated.insert(Args.begin(), Args.end());
315  }
316
317  SmallVectorImpl<ForwardedRegister> &getForwardedMustTailRegParms() {
318    return ForwardedMustTailRegParms;
319  }
320
321  unsigned getTaggedBasePointerOffset() const {
322    return TaggedBasePointerOffset;
323  }
324  void setTaggedBasePointerOffset(unsigned Offset) {
325    TaggedBasePointerOffset = Offset;
326  }
327
328private:
329  // Hold the lists of LOHs.
330  MILOHContainer LOHContainerSet;
331  SetOfInstructions LOHRelated;
332
333  DenseMap<int, std::pair<unsigned, MCSymbol *>> JumpTableEntryInfo;
334};
335
336} // end namespace llvm
337
338#endif // LLVM_LIB_TARGET_AARCH64_AARCH64MACHINEFUNCTIONINFO_H
339