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      1 //===------------------- StackMaps.h - StackMaps ----------------*- 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 #ifndef LLVM_CODEGEN_STACKMAPS_H
     11 #define LLVM_CODEGEN_STACKMAPS_H
     12 
     13 #include "llvm/ADT/MapVector.h"
     14 #include "llvm/ADT/SmallVector.h"
     15 #include "llvm/CodeGen/MachineInstr.h"
     16 #include "llvm/Support/Debug.h"
     17 #include <map>
     18 #include <vector>
     19 
     20 namespace llvm {
     21 
     22 class AsmPrinter;
     23 class MCExpr;
     24 class MCStreamer;
     25 
     26 /// \brief MI-level patchpoint operands.
     27 ///
     28 /// MI patchpoint operations take the form:
     29 /// [<def>], <id>, <numBytes>, <target>, <numArgs>, <cc>, ...
     30 ///
     31 /// IR patchpoint intrinsics do not have the <cc> operand because calling
     32 /// convention is part of the subclass data.
     33 ///
     34 /// SD patchpoint nodes do not have a def operand because it is part of the
     35 /// SDValue.
     36 ///
     37 /// Patchpoints following the anyregcc convention are handled specially. For
     38 /// these, the stack map also records the location of the return value and
     39 /// arguments.
     40 class PatchPointOpers {
     41 public:
     42   /// Enumerate the meta operands.
     43   enum { IDPos, NBytesPos, TargetPos, NArgPos, CCPos, MetaEnd };
     44 
     45 private:
     46   const MachineInstr *MI;
     47   bool HasDef;
     48   bool IsAnyReg;
     49 
     50 public:
     51   explicit PatchPointOpers(const MachineInstr *MI);
     52 
     53   bool isAnyReg() const { return IsAnyReg; }
     54   bool hasDef() const { return HasDef; }
     55 
     56   unsigned getMetaIdx(unsigned Pos = 0) const {
     57     assert(Pos < MetaEnd && "Meta operand index out of range.");
     58     return (HasDef ? 1 : 0) + Pos;
     59   }
     60 
     61   const MachineOperand &getMetaOper(unsigned Pos) {
     62     return MI->getOperand(getMetaIdx(Pos));
     63   }
     64 
     65   unsigned getArgIdx() const { return getMetaIdx() + MetaEnd; }
     66 
     67   /// Get the operand index of the variable list of non-argument operands.
     68   /// These hold the "live state".
     69   unsigned getVarIdx() const {
     70     return getMetaIdx() + MetaEnd +
     71            MI->getOperand(getMetaIdx(NArgPos)).getImm();
     72   }
     73 
     74   /// Get the index at which stack map locations will be recorded.
     75   /// Arguments are not recorded unless the anyregcc convention is used.
     76   unsigned getStackMapStartIdx() const {
     77     if (IsAnyReg)
     78       return getArgIdx();
     79     return getVarIdx();
     80   }
     81 
     82   /// \brief Get the next scratch register operand index.
     83   unsigned getNextScratchIdx(unsigned StartIdx = 0) const;
     84 };
     85 
     86 /// MI-level Statepoint operands
     87 ///
     88 /// Statepoint operands take the form:
     89 ///   <id>, <num patch bytes >, <num call arguments>, <call target>,
     90 ///   [call arguments], <StackMaps::ConstantOp>, <calling convention>,
     91 ///   <StackMaps::ConstantOp>, <statepoint flags>,
     92 ///   <StackMaps::ConstantOp>, <num other args>, [other args],
     93 ///   [gc values]
     94 class StatepointOpers {
     95 private:
     96   // These values are aboolute offsets into the operands of the statepoint
     97   // instruction.
     98   enum { IDPos, NBytesPos, NCallArgsPos, CallTargetPos, MetaEnd };
     99 
    100   // These values are relative offests from the start of the statepoint meta
    101   // arguments (i.e. the end of the call arguments).
    102   enum { CCOffset = 1, FlagsOffset = 3, NumVMSArgsOffset = 5 };
    103 
    104 public:
    105   explicit StatepointOpers(const MachineInstr *MI) : MI(MI) {}
    106 
    107   /// Get starting index of non call related arguments
    108   /// (calling convention, statepoint flags, vm state and gc state).
    109   unsigned getVarIdx() const {
    110     return MI->getOperand(NCallArgsPos).getImm() + MetaEnd;
    111   }
    112 
    113   /// Return the ID for the given statepoint.
    114   uint64_t getID() const { return MI->getOperand(IDPos).getImm(); }
    115 
    116   /// Return the number of patchable bytes the given statepoint should emit.
    117   uint32_t getNumPatchBytes() const {
    118     return MI->getOperand(NBytesPos).getImm();
    119   }
    120 
    121   /// Returns the target of the underlying call.
    122   const MachineOperand &getCallTarget() const {
    123     return MI->getOperand(CallTargetPos);
    124   }
    125 
    126 private:
    127   const MachineInstr *MI;
    128 };
    129 
    130 class StackMaps {
    131 public:
    132   struct Location {
    133     enum LocationType {
    134       Unprocessed,
    135       Register,
    136       Direct,
    137       Indirect,
    138       Constant,
    139       ConstantIndex
    140     };
    141     LocationType Type;
    142     unsigned Size;
    143     unsigned Reg;
    144     int64_t Offset;
    145     Location() : Type(Unprocessed), Size(0), Reg(0), Offset(0) {}
    146     Location(LocationType Type, unsigned Size, unsigned Reg, int64_t Offset)
    147         : Type(Type), Size(Size), Reg(Reg), Offset(Offset) {}
    148   };
    149 
    150   struct LiveOutReg {
    151     unsigned short Reg;
    152     unsigned short DwarfRegNum;
    153     unsigned short Size;
    154 
    155     LiveOutReg() : Reg(0), DwarfRegNum(0), Size(0) {}
    156     LiveOutReg(unsigned short Reg, unsigned short DwarfRegNum,
    157                unsigned short Size)
    158         : Reg(Reg), DwarfRegNum(DwarfRegNum), Size(Size) {}
    159   };
    160 
    161   // OpTypes are used to encode information about the following logical
    162   // operand (which may consist of several MachineOperands) for the
    163   // OpParser.
    164   typedef enum { DirectMemRefOp, IndirectMemRefOp, ConstantOp } OpType;
    165 
    166   StackMaps(AsmPrinter &AP);
    167 
    168   void reset() {
    169     CSInfos.clear();
    170     ConstPool.clear();
    171     FnStackSize.clear();
    172   }
    173 
    174   /// \brief Generate a stackmap record for a stackmap instruction.
    175   ///
    176   /// MI must be a raw STACKMAP, not a PATCHPOINT.
    177   void recordStackMap(const MachineInstr &MI);
    178 
    179   /// \brief Generate a stackmap record for a patchpoint instruction.
    180   void recordPatchPoint(const MachineInstr &MI);
    181 
    182   /// \brief Generate a stackmap record for a statepoint instruction.
    183   void recordStatepoint(const MachineInstr &MI);
    184 
    185   /// If there is any stack map data, create a stack map section and serialize
    186   /// the map info into it. This clears the stack map data structures
    187   /// afterwards.
    188   void serializeToStackMapSection();
    189 
    190 private:
    191   static const char *WSMP;
    192   typedef SmallVector<Location, 8> LocationVec;
    193   typedef SmallVector<LiveOutReg, 8> LiveOutVec;
    194   typedef MapVector<uint64_t, uint64_t> ConstantPool;
    195   typedef MapVector<const MCSymbol *, uint64_t> FnStackSizeMap;
    196 
    197   struct CallsiteInfo {
    198     const MCExpr *CSOffsetExpr;
    199     uint64_t ID;
    200     LocationVec Locations;
    201     LiveOutVec LiveOuts;
    202     CallsiteInfo() : CSOffsetExpr(nullptr), ID(0) {}
    203     CallsiteInfo(const MCExpr *CSOffsetExpr, uint64_t ID,
    204                  LocationVec &&Locations, LiveOutVec &&LiveOuts)
    205         : CSOffsetExpr(CSOffsetExpr), ID(ID), Locations(std::move(Locations)),
    206           LiveOuts(std::move(LiveOuts)) {}
    207   };
    208 
    209   typedef std::vector<CallsiteInfo> CallsiteInfoList;
    210 
    211   AsmPrinter &AP;
    212   CallsiteInfoList CSInfos;
    213   ConstantPool ConstPool;
    214   FnStackSizeMap FnStackSize;
    215 
    216   MachineInstr::const_mop_iterator
    217   parseOperand(MachineInstr::const_mop_iterator MOI,
    218                MachineInstr::const_mop_iterator MOE, LocationVec &Locs,
    219                LiveOutVec &LiveOuts) const;
    220 
    221   /// \brief Create a live-out register record for the given register @p Reg.
    222   LiveOutReg createLiveOutReg(unsigned Reg,
    223                               const TargetRegisterInfo *TRI) const;
    224 
    225   /// \brief Parse the register live-out mask and return a vector of live-out
    226   /// registers that need to be recorded in the stackmap.
    227   LiveOutVec parseRegisterLiveOutMask(const uint32_t *Mask) const;
    228 
    229   /// This should be called by the MC lowering code _immediately_ before
    230   /// lowering the MI to an MCInst. It records where the operands for the
    231   /// instruction are stored, and outputs a label to record the offset of
    232   /// the call from the start of the text section. In special cases (e.g. AnyReg
    233   /// calling convention) the return register is also recorded if requested.
    234   void recordStackMapOpers(const MachineInstr &MI, uint64_t ID,
    235                            MachineInstr::const_mop_iterator MOI,
    236                            MachineInstr::const_mop_iterator MOE,
    237                            bool recordResult = false);
    238 
    239   /// \brief Emit the stackmap header.
    240   void emitStackmapHeader(MCStreamer &OS);
    241 
    242   /// \brief Emit the function frame record for each function.
    243   void emitFunctionFrameRecords(MCStreamer &OS);
    244 
    245   /// \brief Emit the constant pool.
    246   void emitConstantPoolEntries(MCStreamer &OS);
    247 
    248   /// \brief Emit the callsite info for each stackmap/patchpoint intrinsic call.
    249   void emitCallsiteEntries(MCStreamer &OS);
    250 
    251   void print(raw_ostream &OS);
    252   void debug() { print(dbgs()); }
    253 };
    254 }
    255 
    256 #endif
    257