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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/MC/MCSymbol.h"
17 #include <vector>
18 
19 namespace llvm {
20 
21 class AsmPrinter;
22 class MCExpr;
23 class MCStreamer;
24 
25 /// \brief MI-level patchpoint operands.
26 ///
27 /// MI patchpoint operations take the form:
28 /// [<def>], <id>, <numBytes>, <target>, <numArgs>, <cc>, ...
29 ///
30 /// IR patchpoint intrinsics do not have the <cc> operand because calling
31 /// convention is part of the subclass data.
32 ///
33 /// SD patchpoint nodes do not have a def operand because it is part of the
34 /// SDValue.
35 ///
36 /// Patchpoints following the anyregcc convention are handled specially. For
37 /// these, the stack map also records the location of the return value and
38 /// arguments.
39 class PatchPointOpers {
40 public:
41   /// Enumerate the meta operands.
42   enum { IDPos, NBytesPos, TargetPos, NArgPos, CCPos, MetaEnd };
43 
44 private:
45   const MachineInstr *MI;
46   bool HasDef;
47   bool IsAnyReg;
48 
49 public:
50   explicit PatchPointOpers(const MachineInstr *MI);
51 
isAnyReg()52   bool isAnyReg() const { return IsAnyReg; }
hasDef()53   bool hasDef() const { return HasDef; }
54 
55   unsigned getMetaIdx(unsigned Pos = 0) const {
56     assert(Pos < MetaEnd && "Meta operand index out of range.");
57     return (HasDef ? 1 : 0) + Pos;
58   }
59 
getMetaOper(unsigned Pos)60   const MachineOperand &getMetaOper(unsigned Pos) {
61     return MI->getOperand(getMetaIdx(Pos));
62   }
63 
getArgIdx()64   unsigned getArgIdx() const { return getMetaIdx() + MetaEnd; }
65 
66   /// Get the operand index of the variable list of non-argument operands.
67   /// These hold the "live state".
getVarIdx()68   unsigned getVarIdx() const {
69     return getMetaIdx() + MetaEnd +
70            MI->getOperand(getMetaIdx(NArgPos)).getImm();
71   }
72 
73   /// Get the index at which stack map locations will be recorded.
74   /// Arguments are not recorded unless the anyregcc convention is used.
getStackMapStartIdx()75   unsigned getStackMapStartIdx() const {
76     if (IsAnyReg)
77       return getArgIdx();
78     return getVarIdx();
79   }
80 
81   /// \brief Get the next scratch register operand index.
82   unsigned getNextScratchIdx(unsigned StartIdx = 0) const;
83 };
84 
85 /// MI-level Statepoint operands
86 ///
87 /// Statepoint operands take the form:
88 ///   <id>, <num patch bytes >, <num call arguments>, <call target>,
89 ///   [call arguments], <StackMaps::ConstantOp>, <calling convention>,
90 ///   <StackMaps::ConstantOp>, <statepoint flags>,
91 ///   <StackMaps::ConstantOp>, <num other args>, [other args],
92 ///   [gc values]
93 class StatepointOpers {
94 private:
95   // These values are aboolute offsets into the operands of the statepoint
96   // instruction.
97   enum { IDPos, NBytesPos, NCallArgsPos, CallTargetPos, MetaEnd };
98 
99   // These values are relative offests from the start of the statepoint meta
100   // arguments (i.e. the end of the call arguments).
101   enum { CCOffset = 1, FlagsOffset = 3, NumVMSArgsOffset = 5 };
102 
103 public:
StatepointOpers(const MachineInstr * MI)104   explicit StatepointOpers(const MachineInstr *MI) : MI(MI) {}
105 
106   /// Get starting index of non call related arguments
107   /// (calling convention, statepoint flags, vm state and gc state).
getVarIdx()108   unsigned getVarIdx() const {
109     return MI->getOperand(NCallArgsPos).getImm() + MetaEnd;
110   }
111 
112   /// Return the ID for the given statepoint.
getID()113   uint64_t getID() const { return MI->getOperand(IDPos).getImm(); }
114 
115   /// Return the number of patchable bytes the given statepoint should emit.
getNumPatchBytes()116   uint32_t getNumPatchBytes() const {
117     return MI->getOperand(NBytesPos).getImm();
118   }
119 
120   /// Returns the target of the underlying call.
getCallTarget()121   const MachineOperand &getCallTarget() const {
122     return MI->getOperand(CallTargetPos);
123   }
124 
125 private:
126   const MachineInstr *MI;
127 };
128 
129 class StackMaps {
130 public:
131   struct Location {
132     enum LocationType {
133       Unprocessed,
134       Register,
135       Direct,
136       Indirect,
137       Constant,
138       ConstantIndex
139     };
140     LocationType Type;
141     unsigned Size;
142     unsigned Reg;
143     int64_t Offset;
LocationLocation144     Location() : Type(Unprocessed), Size(0), Reg(0), Offset(0) {}
LocationLocation145     Location(LocationType Type, unsigned Size, unsigned Reg, int64_t Offset)
146         : Type(Type), Size(Size), Reg(Reg), Offset(Offset) {}
147   };
148 
149   struct LiveOutReg {
150     unsigned short Reg;
151     unsigned short DwarfRegNum;
152     unsigned short Size;
153 
LiveOutRegLiveOutReg154     LiveOutReg() : Reg(0), DwarfRegNum(0), Size(0) {}
LiveOutRegLiveOutReg155     LiveOutReg(unsigned short Reg, unsigned short DwarfRegNum,
156                unsigned short Size)
157         : Reg(Reg), DwarfRegNum(DwarfRegNum), Size(Size) {}
158   };
159 
160   // OpTypes are used to encode information about the following logical
161   // operand (which may consist of several MachineOperands) for the
162   // OpParser.
163   typedef enum { DirectMemRefOp, IndirectMemRefOp, ConstantOp } OpType;
164 
165   StackMaps(AsmPrinter &AP);
166 
reset()167   void reset() {
168     CSInfos.clear();
169     ConstPool.clear();
170     FnStackSize.clear();
171   }
172 
173   /// \brief Generate a stackmap record for a stackmap instruction.
174   ///
175   /// MI must be a raw STACKMAP, not a PATCHPOINT.
176   void recordStackMap(const MachineInstr &MI);
177 
178   /// \brief Generate a stackmap record for a patchpoint instruction.
179   void recordPatchPoint(const MachineInstr &MI);
180 
181   /// \brief Generate a stackmap record for a statepoint instruction.
182   void recordStatepoint(const MachineInstr &MI);
183 
184   /// If there is any stack map data, create a stack map section and serialize
185   /// the map info into it. This clears the stack map data structures
186   /// afterwards.
187   void serializeToStackMapSection();
188 
189 private:
190   static const char *WSMP;
191   typedef SmallVector<Location, 8> LocationVec;
192   typedef SmallVector<LiveOutReg, 8> LiveOutVec;
193   typedef MapVector<uint64_t, uint64_t> ConstantPool;
194   typedef MapVector<const MCSymbol *, uint64_t> FnStackSizeMap;
195 
196   struct CallsiteInfo {
197     const MCExpr *CSOffsetExpr;
198     uint64_t ID;
199     LocationVec Locations;
200     LiveOutVec LiveOuts;
CallsiteInfoCallsiteInfo201     CallsiteInfo() : CSOffsetExpr(nullptr), ID(0) {}
CallsiteInfoCallsiteInfo202     CallsiteInfo(const MCExpr *CSOffsetExpr, uint64_t ID,
203                  LocationVec &&Locations, LiveOutVec &&LiveOuts)
204         : CSOffsetExpr(CSOffsetExpr), ID(ID), Locations(std::move(Locations)),
205           LiveOuts(std::move(LiveOuts)) {}
206   };
207 
208   typedef std::vector<CallsiteInfo> CallsiteInfoList;
209 
210   AsmPrinter &AP;
211   CallsiteInfoList CSInfos;
212   ConstantPool ConstPool;
213   FnStackSizeMap FnStackSize;
214 
215   MachineInstr::const_mop_iterator
216   parseOperand(MachineInstr::const_mop_iterator MOI,
217                MachineInstr::const_mop_iterator MOE, LocationVec &Locs,
218                LiveOutVec &LiveOuts) const;
219 
220   /// \brief Create a live-out register record for the given register @p Reg.
221   LiveOutReg createLiveOutReg(unsigned Reg,
222                               const TargetRegisterInfo *TRI) const;
223 
224   /// \brief Parse the register live-out mask and return a vector of live-out
225   /// registers that need to be recorded in the stackmap.
226   LiveOutVec parseRegisterLiveOutMask(const uint32_t *Mask) const;
227 
228   /// This should be called by the MC lowering code _immediately_ before
229   /// lowering the MI to an MCInst. It records where the operands for the
230   /// instruction are stored, and outputs a label to record the offset of
231   /// the call from the start of the text section. In special cases (e.g. AnyReg
232   /// calling convention) the return register is also recorded if requested.
233   void recordStackMapOpers(const MachineInstr &MI, uint64_t ID,
234                            MachineInstr::const_mop_iterator MOI,
235                            MachineInstr::const_mop_iterator MOE,
236                            bool recordResult = false);
237 
238   /// \brief Emit the stackmap header.
239   void emitStackmapHeader(MCStreamer &OS);
240 
241   /// \brief Emit the function frame record for each function.
242   void emitFunctionFrameRecords(MCStreamer &OS);
243 
244   /// \brief Emit the constant pool.
245   void emitConstantPoolEntries(MCStreamer &OS);
246 
247   /// \brief Emit the callsite info for each stackmap/patchpoint intrinsic call.
248   void emitCallsiteEntries(MCStreamer &OS);
249 
250   void print(raw_ostream &OS);
debug()251   void debug() { print(dbgs()); }
252 };
253 }
254 
255 #endif
256