lib/Target/AArch64/AArch64MachineFunctionInfo.h

   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/MC/MCLinkerOptimizationHint.h"
  23 #include <cassert>
  24
  25 namespace llvm {
  26
  27 class MachineInstr;
  28
  29 /// AArch64FunctionInfo - This class is derived from MachineFunctionInfo and
  30 /// contains private AArch64-specific information for each MachineFunction.
  31 class AArch64FunctionInfo final : public MachineFunctionInfo {
  32   /// Number of bytes of arguments this function has on the stack. If the callee
  33   /// is expected to restore the argument stack this should be a multiple of 16,
  34   /// all usable during a tail call.
  35   ///
  36   /// The alternative would forbid tail call optimisation in some cases: if we
  37   /// want to transfer control from a function with 8-bytes of stack-argument
  38   /// space to a function with 16-bytes then misalignment of this value would
  39   /// make a stack adjustment necessary, which could not be undone by the
  40   /// callee.
  41   unsigned BytesInStackArgArea = 0;
  42
  43   /// The number of bytes to restore to deallocate space for incoming
  44   /// arguments. Canonically 0 in the C calling convention, but non-zero when
  45   /// callee is expected to pop the args.
  46   unsigned ArgumentStackToRestore = 0;
  47
  48   /// HasStackFrame - True if this function has a stack frame. Set by
  49   /// determineCalleeSaves().
  50   bool HasStackFrame = false;
  51
  52   /// Amount of stack frame size, not including callee-saved registers.
  53   unsigned LocalStackSize;
  54
  55   /// Amount of stack frame size used for saving callee-saved registers.
  56   unsigned CalleeSavedStackSize;
  57
  58   /// Number of TLS accesses using the special (combinable)
  59   /// _TLS_MODULE_BASE_ symbol.
  60   unsigned NumLocalDynamicTLSAccesses = 0;
  61
  62   /// FrameIndex for start of varargs area for arguments passed on the
  63   /// stack.
  64   int VarArgsStackIndex = 0;
  65
  66   /// FrameIndex for start of varargs area for arguments passed in
  67   /// general purpose registers.
  68   int VarArgsGPRIndex = 0;
  69
  70   /// Size of the varargs area for arguments passed in general purpose
  71   /// registers.
  72   unsigned VarArgsGPRSize = 0;
  73
  74   /// FrameIndex for start of varargs area for arguments passed in
  75   /// floating-point registers.
  76   int VarArgsFPRIndex = 0;
  77
  78   /// Size of the varargs area for arguments passed in floating-point
  79   /// registers.
  80   unsigned VarArgsFPRSize = 0;
  81
  82   /// True if this function has a subset of CSRs that is handled explicitly via
  83   /// copies.
  84   bool IsSplitCSR = false;
  85
  86   /// True when the stack gets realigned dynamically because the size of stack
  87   /// frame is unknown at compile time. e.g., in case of VLAs.
  88   bool StackRealigned = false;
  89
  90   /// True when the callee-save stack area has unused gaps that may be used for
  91   /// other stack allocations.
  92   bool CalleeSaveStackHasFreeSpace = false;
  93
  94   /// SRetReturnReg - sret lowering includes returning the value of the
  95   /// returned struct in a register. This field holds the virtual register into
  96   /// which the sret argument is passed.
  97   unsigned SRetReturnReg = 0;
  98
  99   /// Has a value when it is known whether or not the function uses a
 100   /// redzone, and no value otherwise.
 101   /// Initialized during frame lowering, unless the function has the noredzone
 102   /// attribute, in which case it is set to false at construction.
 103   Optional<bool> HasRedZone;
 104
 105   /// ForwardedMustTailRegParms - A list of virtual and physical registers
 106   /// that must be forwarded to every musttail call.
 107   SmallVector<ForwardedRegister, 1> ForwardedMustTailRegParms;
 108
 109   // Offset from SP-at-entry to the tagged base pointer.
 110   // Tagged base pointer is set up to point to the first (lowest address) tagged
 111   // stack slot.
 112   unsigned TaggedBasePointerOffset;
 113
 114 public:
 115   AArch64FunctionInfo() = default;
 116
 117   explicit AArch64FunctionInfo(MachineFunction &MF) {
 118     (void)MF;
 119
 120     // If we already know that the function doesn't have a redzone, set
 121     // HasRedZone here.
 122     if (MF.getFunction().hasFnAttribute(Attribute::NoRedZone))
 123       HasRedZone = false;
 124   }
 125
 126   unsigned getBytesInStackArgArea() const { return BytesInStackArgArea; }
 127   void setBytesInStackArgArea(unsigned bytes) { BytesInStackArgArea = bytes; }
 128
 129   unsigned getArgumentStackToRestore() const { return ArgumentStackToRestore; }
 130   void setArgumentStackToRestore(unsigned bytes) {
 131     ArgumentStackToRestore = bytes;
 132   }
 133
 134   bool hasStackFrame() const { return HasStackFrame; }
 135   void setHasStackFrame(bool s) { HasStackFrame = s; }
 136
 137   bool isStackRealigned() const { return StackRealigned; }
 138   void setStackRealigned(bool s) { StackRealigned = s; }
 139
 140   bool hasCalleeSaveStackFreeSpace() const {
 141     return CalleeSaveStackHasFreeSpace;
 142   }
 143   void setCalleeSaveStackHasFreeSpace(bool s) {
 144     CalleeSaveStackHasFreeSpace = s;
 145   }
 146
 147   bool isSplitCSR() const { return IsSplitCSR; }
 148   void setIsSplitCSR(bool s) { IsSplitCSR = s; }
 149
 150   void setLocalStackSize(unsigned Size) { LocalStackSize = Size; }
 151   unsigned getLocalStackSize() const { return LocalStackSize; }
 152
 153   void setCalleeSavedStackSize(unsigned Size) { CalleeSavedStackSize = Size; }
 154   unsigned getCalleeSavedStackSize() const { return CalleeSavedStackSize; }
 155
 156   void incNumLocalDynamicTLSAccesses() { ++NumLocalDynamicTLSAccesses; }
 157   unsigned getNumLocalDynamicTLSAccesses() const {
 158     return NumLocalDynamicTLSAccesses;
 159   }
 160
 161   Optional<bool> hasRedZone() const { return HasRedZone; }
 162   void setHasRedZone(bool s) { HasRedZone = s; }
 163
 164   int getVarArgsStackIndex() const { return VarArgsStackIndex; }
 165   void setVarArgsStackIndex(int Index) { VarArgsStackIndex = Index; }
 166
 167   int getVarArgsGPRIndex() const { return VarArgsGPRIndex; }
 168   void setVarArgsGPRIndex(int Index) { VarArgsGPRIndex = Index; }
 169
 170   unsigned getVarArgsGPRSize() const { return VarArgsGPRSize; }
 171   void setVarArgsGPRSize(unsigned Size) { VarArgsGPRSize = Size; }
 172
 173   int getVarArgsFPRIndex() const { return VarArgsFPRIndex; }
 174   void setVarArgsFPRIndex(int Index) { VarArgsFPRIndex = Index; }
 175
 176   unsigned getVarArgsFPRSize() const { return VarArgsFPRSize; }
 177   void setVarArgsFPRSize(unsigned Size) { VarArgsFPRSize = Size; }
 178
 179   unsigned getSRetReturnReg() const { return SRetReturnReg; }
 180   void setSRetReturnReg(unsigned Reg) { SRetReturnReg = Reg; }
 181
 182   unsigned getJumpTableEntrySize(int Idx) const {
 183     auto It = JumpTableEntryInfo.find(Idx);
 184     if (It != JumpTableEntryInfo.end())
 185       return It->second.first;
 186     return 4;
 187   }
 188   MCSymbol *getJumpTableEntryPCRelSymbol(int Idx) const {
 189     return JumpTableEntryInfo.find(Idx)->second.second;
 190   }
 191   void setJumpTableEntryInfo(int Idx, unsigned Size, MCSymbol *PCRelSym) {
 192     JumpTableEntryInfo[Idx] = std::make_pair(Size, PCRelSym);
 193   }
 194
 195   using SetOfInstructions = SmallPtrSet<const MachineInstr *, 16>;
 196
 197   const SetOfInstructions &getLOHRelated() const { return LOHRelated; }
 198
 199   // Shortcuts for LOH related types.
 200   class MILOHDirective {
 201     MCLOHType Kind;
 202
 203     /// Arguments of this directive. Order matters.
 204     SmallVector<const MachineInstr *, 3> Args;
 205
 206   public:
 207     using LOHArgs = ArrayRef<const MachineInstr *>;
 208
 209     MILOHDirective(MCLOHType Kind, LOHArgs Args)
 210         : Kind(Kind), Args(Args.begin(), Args.end()) {
 211       assert(isValidMCLOHType(Kind) && "Invalid LOH directive type!");
 212     }
 213
 214     MCLOHType getKind() const { return Kind; }
 215     LOHArgs getArgs() const { return Args; }
 216   };
 217
 218   using MILOHArgs = MILOHDirective::LOHArgs;
 219   using MILOHContainer = SmallVector<MILOHDirective, 32>;
 220
 221   const MILOHContainer &getLOHContainer() const { return LOHContainerSet; }
 222
 223   /// Add a LOH directive of this @p Kind and this @p Args.
 224   void addLOHDirective(MCLOHType Kind, MILOHArgs Args) {
 225     LOHContainerSet.push_back(MILOHDirective(Kind, Args));
 226     LOHRelated.insert(Args.begin(), Args.end());
 227   }
 228
 229   SmallVectorImpl<ForwardedRegister> &getForwardedMustTailRegParms() {
 230     return ForwardedMustTailRegParms;
 231   }
 232
 233   unsigned getTaggedBasePointerOffset() const {
 234     return TaggedBasePointerOffset;
 235   }
 236   void setTaggedBasePointerOffset(unsigned Offset) {
 237     TaggedBasePointerOffset = Offset;
 238   }
 239
 240 private:
 241   // Hold the lists of LOHs.
 242   MILOHContainer LOHContainerSet;
 243   SetOfInstructions LOHRelated;
 244
 245   DenseMap<int, std::pair<unsigned, MCSymbol *>> JumpTableEntryInfo;
 246 };
 247
 248 } // end namespace llvm
 249
 250 #endif // LLVM_LIB_TARGET_AARCH64_AARCH64MACHINEFUNCTIONINFO_H