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/IR/CallingConv.h"
17#include "llvm/Support/Debug.h"
18#include <algorithm>
19#include <cassert>
20#include <cstdint>
21#include <vector>
22
23namespace llvm {
24
25class AsmPrinter;
26class MCExpr;
27class MCStreamer;
28class MCSymbol;
29class raw_ostream;
30class TargetRegisterInfo;
31
32/// \brief MI-level stackmap operands.
33///
34/// MI stackmap operations take the form:
35/// <id>, <numBytes>, live args...
36class StackMapOpers {
37public:
38  /// Enumerate the meta operands.
39  enum { IDPos, NBytesPos };
40
41private:
42  const MachineInstr* MI;
43
44public:
45  explicit StackMapOpers(const MachineInstr *MI);
46
47  /// Return the ID for the given stackmap
48  uint64_t getID() const { return MI->getOperand(IDPos).getImm(); }
49
50  /// Return the number of patchable bytes the given stackmap should emit.
51  uint32_t getNumPatchBytes() const {
52    return MI->getOperand(NBytesPos).getImm();
53  }
54
55  /// Get the operand index of the variable list of non-argument operands.
56  /// These hold the "live state".
57  unsigned getVarIdx() const {
58    // Skip ID, nShadowBytes.
59    return 2;
60  }
61};
62
63/// \brief MI-level patchpoint operands.
64///
65/// MI patchpoint operations take the form:
66/// [<def>], <id>, <numBytes>, <target>, <numArgs>, <cc>, ...
67///
68/// IR patchpoint intrinsics do not have the <cc> operand because calling
69/// convention is part of the subclass data.
70///
71/// SD patchpoint nodes do not have a def operand because it is part of the
72/// SDValue.
73///
74/// Patchpoints following the anyregcc convention are handled specially. For
75/// these, the stack map also records the location of the return value and
76/// arguments.
77class PatchPointOpers {
78public:
79  /// Enumerate the meta operands.
80  enum { IDPos, NBytesPos, TargetPos, NArgPos, CCPos, MetaEnd };
81
82private:
83  const MachineInstr *MI;
84  bool HasDef;
85
86  unsigned getMetaIdx(unsigned Pos = 0) const {
87    assert(Pos < MetaEnd && "Meta operand index out of range.");
88    return (HasDef ? 1 : 0) + Pos;
89  }
90
91  const MachineOperand &getMetaOper(unsigned Pos) const {
92    return MI->getOperand(getMetaIdx(Pos));
93  }
94
95public:
96  explicit PatchPointOpers(const MachineInstr *MI);
97
98  bool isAnyReg() const { return (getCallingConv() == CallingConv::AnyReg); }
99  bool hasDef() const { return HasDef; }
100
101  /// Return the ID for the given patchpoint.
102  uint64_t getID() const { return getMetaOper(IDPos).getImm(); }
103
104  /// Return the number of patchable bytes the given patchpoint should emit.
105  uint32_t getNumPatchBytes() const {
106    return getMetaOper(NBytesPos).getImm();
107  }
108
109  /// Returns the target of the underlying call.
110  const MachineOperand &getCallTarget() const {
111    return getMetaOper(TargetPos);
112  }
113
114  /// Returns the calling convention
115  CallingConv::ID getCallingConv() const {
116    return getMetaOper(CCPos).getImm();
117  }
118
119  unsigned getArgIdx() const { return getMetaIdx() + MetaEnd; }
120
121  /// Return the number of call arguments
122  uint32_t getNumCallArgs() const {
123    return MI->getOperand(getMetaIdx(NArgPos)).getImm();
124  }
125
126  /// Get the operand index of the variable list of non-argument operands.
127  /// These hold the "live state".
128  unsigned getVarIdx() const {
129    return getMetaIdx() + MetaEnd + getNumCallArgs();
130  }
131
132  /// Get the index at which stack map locations will be recorded.
133  /// Arguments are not recorded unless the anyregcc convention is used.
134  unsigned getStackMapStartIdx() const {
135    if (isAnyReg())
136      return getArgIdx();
137    return getVarIdx();
138  }
139
140  /// \brief Get the next scratch register operand index.
141  unsigned getNextScratchIdx(unsigned StartIdx = 0) const;
142};
143
144/// MI-level Statepoint operands
145///
146/// Statepoint operands take the form:
147///   <id>, <num patch bytes >, <num call arguments>, <call target>,
148///   [call arguments...],
149///   <StackMaps::ConstantOp>, <calling convention>,
150///   <StackMaps::ConstantOp>, <statepoint flags>,
151///   <StackMaps::ConstantOp>, <num deopt args>, [deopt args...],
152///   <gc base/derived pairs...> <gc allocas...>
153/// Note that the last two sets of arguments are not currently length
154///   prefixed.
155class StatepointOpers {
156  // TODO:: we should change the STATEPOINT representation so that CC and
157  // Flags should be part of meta operands, with args and deopt operands, and
158  // gc operands all prefixed by their length and a type code. This would be
159  // much more consistent.
160public:
161  // These values are aboolute offsets into the operands of the statepoint
162  // instruction.
163  enum { IDPos, NBytesPos, NCallArgsPos, CallTargetPos, MetaEnd };
164
165  // These values are relative offests from the start of the statepoint meta
166  // arguments (i.e. the end of the call arguments).
167  enum { CCOffset = 1, FlagsOffset = 3, NumDeoptOperandsOffset = 5 };
168
169  explicit StatepointOpers(const MachineInstr *MI) : MI(MI) {}
170
171  /// Get starting index of non call related arguments
172  /// (calling convention, statepoint flags, vm state and gc state).
173  unsigned getVarIdx() const {
174    return MI->getOperand(NCallArgsPos).getImm() + MetaEnd;
175  }
176
177  /// Return the ID for the given statepoint.
178  uint64_t getID() const { return MI->getOperand(IDPos).getImm(); }
179
180  /// Return the number of patchable bytes the given statepoint should emit.
181  uint32_t getNumPatchBytes() const {
182    return MI->getOperand(NBytesPos).getImm();
183  }
184
185  /// Returns the target of the underlying call.
186  const MachineOperand &getCallTarget() const {
187    return MI->getOperand(CallTargetPos);
188  }
189
190private:
191  const MachineInstr *MI;
192};
193
194class StackMaps {
195public:
196  struct Location {
197    enum LocationType {
198      Unprocessed,
199      Register,
200      Direct,
201      Indirect,
202      Constant,
203      ConstantIndex
204    };
205    LocationType Type = Unprocessed;
206    unsigned Size = 0;
207    unsigned Reg = 0;
208    int64_t Offset = 0;
209
210    Location() = default;
211    Location(LocationType Type, unsigned Size, unsigned Reg, int64_t Offset)
212        : Type(Type), Size(Size), Reg(Reg), Offset(Offset) {}
213  };
214
215  struct LiveOutReg {
216    unsigned short Reg = 0;
217    unsigned short DwarfRegNum = 0;
218    unsigned short Size = 0;
219
220    LiveOutReg() = default;
221    LiveOutReg(unsigned short Reg, unsigned short DwarfRegNum,
222               unsigned short Size)
223        : Reg(Reg), DwarfRegNum(DwarfRegNum), Size(Size) {}
224  };
225
226  // OpTypes are used to encode information about the following logical
227  // operand (which may consist of several MachineOperands) for the
228  // OpParser.
229  using OpType = enum { DirectMemRefOp, IndirectMemRefOp, ConstantOp };
230
231  StackMaps(AsmPrinter &AP);
232
233  void reset() {
234    CSInfos.clear();
235    ConstPool.clear();
236    FnInfos.clear();
237  }
238
239  /// \brief Generate a stackmap record for a stackmap instruction.
240  ///
241  /// MI must be a raw STACKMAP, not a PATCHPOINT.
242  void recordStackMap(const MachineInstr &MI);
243
244  /// \brief Generate a stackmap record for a patchpoint instruction.
245  void recordPatchPoint(const MachineInstr &MI);
246
247  /// \brief Generate a stackmap record for a statepoint instruction.
248  void recordStatepoint(const MachineInstr &MI);
249
250  /// If there is any stack map data, create a stack map section and serialize
251  /// the map info into it. This clears the stack map data structures
252  /// afterwards.
253  void serializeToStackMapSection();
254
255private:
256  static const char *WSMP;
257
258  using LocationVec = SmallVector<Location, 8>;
259  using LiveOutVec = SmallVector<LiveOutReg, 8>;
260  using ConstantPool = MapVector<uint64_t, uint64_t>;
261
262  struct FunctionInfo {
263    uint64_t StackSize = 0;
264    uint64_t RecordCount = 1;
265
266    FunctionInfo() = default;
267    explicit FunctionInfo(uint64_t StackSize) : StackSize(StackSize) {}
268  };
269
270  struct CallsiteInfo {
271    const MCExpr *CSOffsetExpr = nullptr;
272    uint64_t ID = 0;
273    LocationVec Locations;
274    LiveOutVec LiveOuts;
275
276    CallsiteInfo() = default;
277    CallsiteInfo(const MCExpr *CSOffsetExpr, uint64_t ID,
278                 LocationVec &&Locations, LiveOutVec &&LiveOuts)
279        : CSOffsetExpr(CSOffsetExpr), ID(ID), Locations(std::move(Locations)),
280          LiveOuts(std::move(LiveOuts)) {}
281  };
282
283  using FnInfoMap = MapVector<const MCSymbol *, FunctionInfo>;
284  using CallsiteInfoList = std::vector<CallsiteInfo>;
285
286  AsmPrinter &AP;
287  CallsiteInfoList CSInfos;
288  ConstantPool ConstPool;
289  FnInfoMap FnInfos;
290
291  MachineInstr::const_mop_iterator
292  parseOperand(MachineInstr::const_mop_iterator MOI,
293               MachineInstr::const_mop_iterator MOE, LocationVec &Locs,
294               LiveOutVec &LiveOuts) const;
295
296  /// \brief Create a live-out register record for the given register @p Reg.
297  LiveOutReg createLiveOutReg(unsigned Reg,
298                              const TargetRegisterInfo *TRI) const;
299
300  /// \brief Parse the register live-out mask and return a vector of live-out
301  /// registers that need to be recorded in the stackmap.
302  LiveOutVec parseRegisterLiveOutMask(const uint32_t *Mask) const;
303
304  /// This should be called by the MC lowering code _immediately_ before
305  /// lowering the MI to an MCInst. It records where the operands for the
306  /// instruction are stored, and outputs a label to record the offset of
307  /// the call from the start of the text section. In special cases (e.g. AnyReg
308  /// calling convention) the return register is also recorded if requested.
309  void recordStackMapOpers(const MachineInstr &MI, uint64_t ID,
310                           MachineInstr::const_mop_iterator MOI,
311                           MachineInstr::const_mop_iterator MOE,
312                           bool recordResult = false);
313
314  /// \brief Emit the stackmap header.
315  void emitStackmapHeader(MCStreamer &OS);
316
317  /// \brief Emit the function frame record for each function.
318  void emitFunctionFrameRecords(MCStreamer &OS);
319
320  /// \brief Emit the constant pool.
321  void emitConstantPoolEntries(MCStreamer &OS);
322
323  /// \brief Emit the callsite info for each stackmap/patchpoint intrinsic call.
324  void emitCallsiteEntries(MCStreamer &OS);
325
326  void print(raw_ostream &OS);
327  void debug() { print(dbgs()); }
328};
329
330} // end namespace llvm
331
332#endif // LLVM_CODEGEN_STACKMAPS_H
333