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      1 //===------------------- StackMaps.h - StackMaps ----------------*- C++ -*-===//
      2 
      3 //
      4 //                     The LLVM Compiler Infrastructure
      5 //
      6 // This file is distributed under the University of Illinois Open Source
      7 // License. See LICENSE.TXT for details.
      8 //
      9 //===----------------------------------------------------------------------===//
     10 
     11 #ifndef LLVM_STACKMAPS
     12 #define LLVM_STACKMAPS
     13 
     14 #include "llvm/ADT/MapVector.h"
     15 #include "llvm/ADT/SmallVector.h"
     16 #include "llvm/CodeGen/MachineInstr.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 private:
     45   const MachineInstr *MI;
     46   bool HasDef;
     47   bool IsAnyReg;
     48 public:
     49   explicit PatchPointOpers(const MachineInstr *MI);
     50 
     51   bool isAnyReg() const { return IsAnyReg; }
     52   bool hasDef() const { return HasDef; }
     53 
     54   unsigned getMetaIdx(unsigned Pos = 0) const {
     55     assert(Pos < MetaEnd && "Meta operand index out of range.");
     56     return (HasDef ? 1 : 0) + Pos;
     57   }
     58 
     59   const MachineOperand &getMetaOper(unsigned Pos) {
     60     return MI->getOperand(getMetaIdx(Pos));
     61   }
     62 
     63   unsigned getArgIdx() const { return getMetaIdx() + MetaEnd; }
     64 
     65   /// Get the operand index of the variable list of non-argument operands.
     66   /// These hold the "live state".
     67   unsigned getVarIdx() const {
     68     return getMetaIdx() + MetaEnd
     69       + MI->getOperand(getMetaIdx(NArgPos)).getImm();
     70   }
     71 
     72   /// Get the index at which stack map locations will be recorded.
     73   /// Arguments are not recorded unless the anyregcc convention is used.
     74   unsigned getStackMapStartIdx() const {
     75     if (IsAnyReg)
     76       return getArgIdx();
     77     return getVarIdx();
     78   }
     79 
     80   /// \brief Get the next scratch register operand index.
     81   unsigned getNextScratchIdx(unsigned StartIdx = 0) const;
     82 };
     83 
     84 class StackMaps {
     85 public:
     86   struct Location {
     87     enum LocationType { Unprocessed, Register, Direct, Indirect, Constant,
     88                         ConstantIndex };
     89     LocationType LocType;
     90     unsigned Size;
     91     unsigned Reg;
     92     int64_t Offset;
     93     Location() : LocType(Unprocessed), Size(0), Reg(0), Offset(0) {}
     94     Location(LocationType LocType, unsigned Size, unsigned Reg, int64_t Offset)
     95       : LocType(LocType), Size(Size), Reg(Reg), Offset(Offset) {}
     96   };
     97 
     98   struct LiveOutReg {
     99     unsigned short Reg;
    100     unsigned short RegNo;
    101     unsigned short Size;
    102 
    103     LiveOutReg() : Reg(0), RegNo(0), Size(0) {}
    104     LiveOutReg(unsigned short Reg, unsigned short RegNo, unsigned short Size)
    105       : Reg(Reg), RegNo(RegNo), Size(Size) {}
    106 
    107     void MarkInvalid() { Reg = 0; }
    108 
    109     // Only sort by the dwarf register number.
    110     bool operator< (const LiveOutReg &LO) const { return RegNo < LO.RegNo; }
    111     static bool IsInvalid(const LiveOutReg &LO) { return LO.Reg == 0; }
    112   };
    113 
    114   // OpTypes are used to encode information about the following logical
    115   // operand (which may consist of several MachineOperands) for the
    116   // OpParser.
    117   typedef enum { DirectMemRefOp, IndirectMemRefOp, ConstantOp } OpType;
    118 
    119   StackMaps(AsmPrinter &AP);
    120 
    121   /// \brief Generate a stackmap record for a stackmap instruction.
    122   ///
    123   /// MI must be a raw STACKMAP, not a PATCHPOINT.
    124   void recordStackMap(const MachineInstr &MI);
    125 
    126   /// \brief Generate a stackmap record for a patchpoint instruction.
    127   void recordPatchPoint(const MachineInstr &MI);
    128 
    129   /// If there is any stack map data, create a stack map section and serialize
    130   /// the map info into it. This clears the stack map data structures
    131   /// afterwards.
    132   void serializeToStackMapSection();
    133 
    134 private:
    135   static const char *WSMP;
    136 
    137   typedef SmallVector<Location, 8> LocationVec;
    138   typedef SmallVector<LiveOutReg, 8> LiveOutVec;
    139   typedef MapVector<int64_t, int64_t> ConstantPool;
    140   typedef MapVector<const MCSymbol *, uint64_t> FnStackSizeMap;
    141 
    142   struct CallsiteInfo {
    143     const MCExpr *CSOffsetExpr;
    144     uint64_t ID;
    145     LocationVec Locations;
    146     LiveOutVec LiveOuts;
    147     CallsiteInfo() : CSOffsetExpr(nullptr), ID(0) {}
    148     CallsiteInfo(const MCExpr *CSOffsetExpr, uint64_t ID,
    149                  LocationVec &Locations, LiveOutVec &LiveOuts)
    150       : CSOffsetExpr(CSOffsetExpr), ID(ID), Locations(Locations),
    151         LiveOuts(LiveOuts) {}
    152   };
    153 
    154   typedef std::vector<CallsiteInfo> CallsiteInfoList;
    155 
    156   AsmPrinter &AP;
    157   CallsiteInfoList CSInfos;
    158   ConstantPool ConstPool;
    159   FnStackSizeMap FnStackSize;
    160 
    161   MachineInstr::const_mop_iterator
    162   parseOperand(MachineInstr::const_mop_iterator MOI,
    163                MachineInstr::const_mop_iterator MOE,
    164                LocationVec &Locs, LiveOutVec &LiveOuts) const;
    165 
    166   /// \brief Create a live-out register record for the given register @p Reg.
    167   LiveOutReg createLiveOutReg(unsigned Reg,
    168                               const TargetRegisterInfo *TRI) const;
    169 
    170   /// \brief Parse the register live-out mask and return a vector of live-out
    171   /// registers that need to be recorded in the stackmap.
    172   LiveOutVec parseRegisterLiveOutMask(const uint32_t *Mask) const;
    173 
    174   /// This should be called by the MC lowering code _immediately_ before
    175   /// lowering the MI to an MCInst. It records where the operands for the
    176   /// instruction are stored, and outputs a label to record the offset of
    177   /// the call from the start of the text section. In special cases (e.g. AnyReg
    178   /// calling convention) the return register is also recorded if requested.
    179   void recordStackMapOpers(const MachineInstr &MI, uint64_t ID,
    180                            MachineInstr::const_mop_iterator MOI,
    181                            MachineInstr::const_mop_iterator MOE,
    182                            bool recordResult = false);
    183 
    184   /// \brief Emit the stackmap header.
    185   void emitStackmapHeader(MCStreamer &OS);
    186 
    187   /// \brief Emit the function frame record for each function.
    188   void emitFunctionFrameRecords(MCStreamer &OS);
    189 
    190   /// \brief Emit the constant pool.
    191   void emitConstantPoolEntries(MCStreamer &OS);
    192 
    193   /// \brief Emit the callsite info for each stackmap/patchpoint intrinsic call.
    194   void emitCallsiteEntries(MCStreamer &OS, const TargetRegisterInfo *TRI);
    195 };
    196 
    197 }
    198 
    199 #endif // LLVM_STACKMAPS
    200