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/IR/Function.h"
  23 #include "llvm/MC/MCLinkerOptimizationHint.h"
  24 #include <cassert>
  25
  26 namespace llvm {
  27
  28 class MachineInstr;
  29
  30 /// AArch64FunctionInfo - This class is derived from MachineFunctionInfo and
  31 /// contains private AArch64-specific information for each MachineFunction.
  32 class AArch64FunctionInfo final : public MachineFunctionInfo {
  33   /// Number of bytes of arguments this function has on the stack. If the callee
  34   /// is expected to restore the argument stack this should be a multiple of 16,
  35   /// all usable during a tail call.
  36   ///
  37   /// The alternative would forbid tail call optimisation in some cases: if we
  38   /// want to transfer control from a function with 8-bytes of stack-argument
  39   /// space to a function with 16-bytes then misalignment of this value would
  40   /// make a stack adjustment necessary, which could not be undone by the
  41   /// callee.
  42   unsigned BytesInStackArgArea = 0;
  43
  44   /// The number of bytes to restore to deallocate space for incoming
  45   /// arguments. Canonically 0 in the C calling convention, but non-zero when
  46   /// callee is expected to pop the args.
  47   unsigned ArgumentStackToRestore = 0;
  48
  49   /// HasStackFrame - True if this function has a stack frame. Set by
  50   /// determineCalleeSaves().
  51   bool HasStackFrame = false;
  52
  53   /// Amount of stack frame size, not including callee-saved registers.
  54   unsigned LocalStackSize;
  55
  56   /// Amount of stack frame size used for saving callee-saved registers.
  57   unsigned CalleeSavedStackSize;
  58
  59   /// Number of TLS accesses using the special (combinable)
  60   /// _TLS_MODULE_BASE_ symbol.
  61   unsigned NumLocalDynamicTLSAccesses = 0;
  62
  63   /// FrameIndex for start of varargs area for arguments passed on the
  64   /// stack.
  65   int VarArgsStackIndex = 0;
  66
  67   /// FrameIndex for start of varargs area for arguments passed in
  68   /// general purpose registers.
  69   int VarArgsGPRIndex = 0;
  70
  71   /// Size of the varargs area for arguments passed in general purpose
  72   /// registers.
  73   unsigned VarArgsGPRSize = 0;
  74
  75   /// FrameIndex for start of varargs area for arguments passed in
  76   /// floating-point registers.
  77   int VarArgsFPRIndex = 0;
  78
  79   /// Size of the varargs area for arguments passed in floating-point
  80   /// registers.
  81   unsigned VarArgsFPRSize = 0;
  82
  83   /// True if this function has a subset of CSRs that is handled explicitly via
  84   /// copies.
  85   bool IsSplitCSR = false;
  86
  87   /// True when the stack gets realigned dynamically because the size of stack
  88   /// frame is unknown at compile time. e.g., in case of VLAs.
  89   bool StackRealigned = false;
  90
  91   /// True when the callee-save stack area has unused gaps that may be used for
  92   /// other stack allocations.
  93   bool CalleeSaveStackHasFreeSpace = false;
  94
  95   /// SRetReturnReg - sret lowering includes returning the value of the
  96   /// returned struct in a register. This field holds the virtual register into
  97   /// which the sret argument is passed.
  98   unsigned SRetReturnReg = 0;
  99   /// SVE stack size (for predicates and data vectors) are maintained here
 100   /// rather than in FrameInfo, as the placement and Stack IDs are target
 101   /// specific.
 102   uint64_t StackSizeSVE = 0;
 103
 104   /// HasCalculatedStackSizeSVE indicates whether StackSizeSVE is valid.
 105   bool HasCalculatedStackSizeSVE = false;
 106
 107   /// Has a value when it is known whether or not the function uses a
 108   /// redzone, and no value otherwise.
 109   /// Initialized during frame lowering, unless the function has the noredzone
 110   /// attribute, in which case it is set to false at construction.
 111   Optional<bool> HasRedZone;
 112
 113   /// ForwardedMustTailRegParms - A list of virtual and physical registers
 114   /// that must be forwarded to every musttail call.
 115   SmallVector<ForwardedRegister, 1> ForwardedMustTailRegParms;
 116
 117   // Offset from SP-at-entry to the tagged base pointer.
 118   // Tagged base pointer is set up to point to the first (lowest address) tagged
 119   // stack slot.
 120   unsigned TaggedBasePointerOffset;
 121
 122 public:
 123   AArch64FunctionInfo() = default;
 124
 125   explicit AArch64FunctionInfo(MachineFunction &MF) {
 126     (void)MF;
 127
 128     // If we already know that the function doesn't have a redzone, set
 129     // HasRedZone here.
 130     if (MF.getFunction().hasFnAttribute(Attribute::NoRedZone))
 131       HasRedZone = false;
 132   }
 133
 134   unsigned getBytesInStackArgArea() const { return BytesInStackArgArea; }
 135   void setBytesInStackArgArea(unsigned bytes) { BytesInStackArgArea = bytes; }
 136
 137   unsigned getArgumentStackToRestore() const { return ArgumentStackToRestore; }
 138   void setArgumentStackToRestore(unsigned bytes) {
 139     ArgumentStackToRestore = bytes;
 140   }
 141
 142   bool hasCalculatedStackSizeSVE() const { return HasCalculatedStackSizeSVE; }
 143
 144   void setStackSizeSVE(uint64_t S) {
 145     HasCalculatedStackSizeSVE = true;
 146     StackSizeSVE = S;
 147   }
 148
 149   uint64_t getStackSizeSVE() const { return StackSizeSVE; }
 150
 151   bool hasStackFrame() const { return HasStackFrame; }
 152   void setHasStackFrame(bool s) { HasStackFrame = s; }
 153
 154   bool isStackRealigned() const { return StackRealigned; }
 155   void setStackRealigned(bool s) { StackRealigned = s; }
 156
 157   bool hasCalleeSaveStackFreeSpace() const {
 158     return CalleeSaveStackHasFreeSpace;
 159   }
 160   void setCalleeSaveStackHasFreeSpace(bool s) {
 161     CalleeSaveStackHasFreeSpace = s;
 162   }
 163
 164   bool isSplitCSR() const { return IsSplitCSR; }
 165   void setIsSplitCSR(bool s) { IsSplitCSR = s; }
 166
 167   void setLocalStackSize(unsigned Size) { LocalStackSize = Size; }
 168   unsigned getLocalStackSize() const { return LocalStackSize; }
 169
 170   void setCalleeSavedStackSize(unsigned Size) { CalleeSavedStackSize = Size; }
 171   unsigned getCalleeSavedStackSize() const { return CalleeSavedStackSize; }
 172
 173   void incNumLocalDynamicTLSAccesses() { ++NumLocalDynamicTLSAccesses; }
 174   unsigned getNumLocalDynamicTLSAccesses() const {
 175     return NumLocalDynamicTLSAccesses;
 176   }
 177
 178   Optional<bool> hasRedZone() const { return HasRedZone; }
 179   void setHasRedZone(bool s) { HasRedZone = s; }
 180
 181   int getVarArgsStackIndex() const { return VarArgsStackIndex; }
 182   void setVarArgsStackIndex(int Index) { VarArgsStackIndex = Index; }
 183
 184   int getVarArgsGPRIndex() const { return VarArgsGPRIndex; }
 185   void setVarArgsGPRIndex(int Index) { VarArgsGPRIndex = Index; }
 186
 187   unsigned getVarArgsGPRSize() const { return VarArgsGPRSize; }
 188   void setVarArgsGPRSize(unsigned Size) { VarArgsGPRSize = Size; }
 189
 190   int getVarArgsFPRIndex() const { return VarArgsFPRIndex; }
 191   void setVarArgsFPRIndex(int Index) { VarArgsFPRIndex = Index; }
 192
 193   unsigned getVarArgsFPRSize() const { return VarArgsFPRSize; }
 194   void setVarArgsFPRSize(unsigned Size) { VarArgsFPRSize = Size; }
 195
 196   unsigned getSRetReturnReg() const { return SRetReturnReg; }
 197   void setSRetReturnReg(unsigned Reg) { SRetReturnReg = Reg; }
 198
 199   unsigned getJumpTableEntrySize(int Idx) const {
 200     auto It = JumpTableEntryInfo.find(Idx);
 201     if (It != JumpTableEntryInfo.end())
 202       return It->second.first;
 203     return 4;
 204   }
 205   MCSymbol *getJumpTableEntryPCRelSymbol(int Idx) const {
 206     return JumpTableEntryInfo.find(Idx)->second.second;
 207   }
 208   void setJumpTableEntryInfo(int Idx, unsigned Size, MCSymbol *PCRelSym) {
 209     JumpTableEntryInfo[Idx] = std::make_pair(Size, PCRelSym);
 210   }
 211
 212   using SetOfInstructions = SmallPtrSet<const MachineInstr *, 16>;
 213
 214   const SetOfInstructions &getLOHRelated() const { return LOHRelated; }
 215
 216   // Shortcuts for LOH related types.
 217   class MILOHDirective {
 218     MCLOHType Kind;
 219
 220     /// Arguments of this directive. Order matters.
 221     SmallVector<const MachineInstr *, 3> Args;
 222
 223   public:
 224     using LOHArgs = ArrayRef<const MachineInstr *>;
 225
 226     MILOHDirective(MCLOHType Kind, LOHArgs Args)
 227         : Kind(Kind), Args(Args.begin(), Args.end()) {
 228       assert(isValidMCLOHType(Kind) && "Invalid LOH directive type!");
 229     }
 230
 231     MCLOHType getKind() const { return Kind; }
 232     LOHArgs getArgs() const { return Args; }
 233   };
 234
 235   using MILOHArgs = MILOHDirective::LOHArgs;
 236   using MILOHContainer = SmallVector<MILOHDirective, 32>;
 237
 238   const MILOHContainer &getLOHContainer() const { return LOHContainerSet; }
 239
 240   /// Add a LOH directive of this @p Kind and this @p Args.
 241   void addLOHDirective(MCLOHType Kind, MILOHArgs Args) {
 242     LOHContainerSet.push_back(MILOHDirective(Kind, Args));
 243     LOHRelated.insert(Args.begin(), Args.end());
 244   }
 245
 246   SmallVectorImpl<ForwardedRegister> &getForwardedMustTailRegParms() {
 247     return ForwardedMustTailRegParms;
 248   }
 249
 250   unsigned getTaggedBasePointerOffset() const {
 251     return TaggedBasePointerOffset;
 252   }
 253   void setTaggedBasePointerOffset(unsigned Offset) {
 254     TaggedBasePointerOffset = Offset;
 255   }
 256
 257 private:
 258   // Hold the lists of LOHs.
 259   MILOHContainer LOHContainerSet;
 260   SetOfInstructions LOHRelated;
 261
 262   DenseMap<int, std::pair<unsigned, MCSymbol *>> JumpTableEntryInfo;
 263 };
 264
 265 } // end namespace llvm
 266
 267 #endif // LLVM_LIB_TARGET_AARCH64_AARCH64MACHINEFUNCTIONINFO_H