1 //==- llvm/CodeGen/MachineMemOperand.h - MachineMemOperand class -*- 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 // This file contains the declaration of the MachineMemOperand class, which is a
11 // description of a memory reference. It is used to help track dependencies
12 // in the backend.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #ifndef LLVM_CODEGEN_MACHINEMEMOPERAND_H
17 #define LLVM_CODEGEN_MACHINEMEMOPERAND_H
18 
19 #include "llvm/ADT/PointerUnion.h"
20 #include "llvm/CodeGen/PseudoSourceValue.h"
21 #include "llvm/IR/Metadata.h"
22 #include "llvm/IR/Value.h"  // PointerLikeTypeTraits<Value*>
23 #include "llvm/Support/DataTypes.h"
24 
25 namespace llvm {
26 
27 class FoldingSetNodeID;
28 class MDNode;
29 class raw_ostream;
30 class MachineFunction;
31 class ModuleSlotTracker;
32 
33 /// MachinePointerInfo - This class contains a discriminated union of
34 /// information about pointers in memory operands, relating them back to LLVM IR
35 /// or to virtual locations (such as frame indices) that are exposed during
36 /// codegen.
37 struct MachinePointerInfo {
38   /// V - This is the IR pointer value for the access, or it is null if unknown.
39   /// If this is null, then the access is to a pointer in the default address
40   /// space.
41   PointerUnion<const Value *, const PseudoSourceValue *> V;
42 
43   /// Offset - This is an offset from the base Value*.
44   int64_t Offset;
45 
46   explicit MachinePointerInfo(const Value *v = nullptr, int64_t offset = 0)
VMachinePointerInfo47     : V(v), Offset(offset) {}
48 
49   explicit MachinePointerInfo(const PseudoSourceValue *v,
50                               int64_t offset = 0)
VMachinePointerInfo51     : V(v), Offset(offset) {}
52 
getWithOffsetMachinePointerInfo53   MachinePointerInfo getWithOffset(int64_t O) const {
54     if (V.isNull()) return MachinePointerInfo();
55     if (V.is<const Value*>())
56       return MachinePointerInfo(V.get<const Value*>(), Offset+O);
57     return MachinePointerInfo(V.get<const PseudoSourceValue*>(), Offset+O);
58   }
59 
60   /// getAddrSpace - Return the LLVM IR address space number that this pointer
61   /// points into.
62   unsigned getAddrSpace() const;
63 
64   /// getConstantPool - Return a MachinePointerInfo record that refers to the
65   /// constant pool.
66   static MachinePointerInfo getConstantPool(MachineFunction &MF);
67 
68   /// getFixedStack - Return a MachinePointerInfo record that refers to the
69   /// the specified FrameIndex.
70   static MachinePointerInfo getFixedStack(MachineFunction &MF, int FI,
71                                           int64_t Offset = 0);
72 
73   /// getJumpTable - Return a MachinePointerInfo record that refers to a
74   /// jump table entry.
75   static MachinePointerInfo getJumpTable(MachineFunction &MF);
76 
77   /// getGOT - Return a MachinePointerInfo record that refers to a
78   /// GOT entry.
79   static MachinePointerInfo getGOT(MachineFunction &MF);
80 
81   /// getStack - stack pointer relative access.
82   static MachinePointerInfo getStack(MachineFunction &MF, int64_t Offset);
83 };
84 
85 
86 //===----------------------------------------------------------------------===//
87 /// MachineMemOperand - A description of a memory reference used in the backend.
88 /// Instead of holding a StoreInst or LoadInst, this class holds the address
89 /// Value of the reference along with a byte size and offset. This allows it
90 /// to describe lowered loads and stores. Also, the special PseudoSourceValue
91 /// objects can be used to represent loads and stores to memory locations
92 /// that aren't explicit in the regular LLVM IR.
93 ///
94 class MachineMemOperand {
95   MachinePointerInfo PtrInfo;
96   uint64_t Size;
97   unsigned Flags;
98   AAMDNodes AAInfo;
99   const MDNode *Ranges;
100 
101 public:
102   /// Flags values. These may be or'd together.
103   enum MemOperandFlags {
104     /// The memory access reads data.
105     MOLoad = 1,
106     /// The memory access writes data.
107     MOStore = 2,
108     /// The memory access is volatile.
109     MOVolatile = 4,
110     /// The memory access is non-temporal.
111     MONonTemporal = 8,
112     /// The memory access is invariant.
113     MOInvariant = 16,
114     // Target hints allow target passes to annotate memory operations.
115     MOTargetStartBit = 5,
116     MOTargetNumBits = 3,
117     // This is the number of bits we need to represent flags.
118     MOMaxBits = 8
119   };
120 
121   /// MachineMemOperand - Construct an MachineMemOperand object with the
122   /// specified PtrInfo, flags, size, and base alignment.
123   MachineMemOperand(MachinePointerInfo PtrInfo, unsigned flags, uint64_t s,
124                     unsigned base_alignment,
125                     const AAMDNodes &AAInfo = AAMDNodes(),
126                     const MDNode *Ranges = nullptr);
127 
getPointerInfo()128   const MachinePointerInfo &getPointerInfo() const { return PtrInfo; }
129 
130   /// getValue - Return the base address of the memory access. This may either
131   /// be a normal LLVM IR Value, or one of the special values used in CodeGen.
132   /// Special values are those obtained via
133   /// PseudoSourceValue::getFixedStack(int), PseudoSourceValue::getStack, and
134   /// other PseudoSourceValue member functions which return objects which stand
135   /// for frame/stack pointer relative references and other special references
136   /// which are not representable in the high-level IR.
getValue()137   const Value *getValue() const { return PtrInfo.V.dyn_cast<const Value*>(); }
138 
getPseudoValue()139   const PseudoSourceValue *getPseudoValue() const {
140     return PtrInfo.V.dyn_cast<const PseudoSourceValue*>();
141   }
142 
getOpaqueValue()143   const void *getOpaqueValue() const { return PtrInfo.V.getOpaqueValue(); }
144 
145   /// getFlags - Return the raw flags of the source value, \see MemOperandFlags.
getFlags()146   unsigned int getFlags() const { return Flags & ((1 << MOMaxBits) - 1); }
147 
148   /// Bitwise OR the current flags with the given flags.
setFlags(unsigned f)149   void setFlags(unsigned f) { Flags |= (f & ((1 << MOMaxBits) - 1)); }
150 
151   /// getOffset - For normal values, this is a byte offset added to the base
152   /// address. For PseudoSourceValue::FPRel values, this is the FrameIndex
153   /// number.
getOffset()154   int64_t getOffset() const { return PtrInfo.Offset; }
155 
getAddrSpace()156   unsigned getAddrSpace() const { return PtrInfo.getAddrSpace(); }
157 
158   /// getSize - Return the size in bytes of the memory reference.
getSize()159   uint64_t getSize() const { return Size; }
160 
161   /// getAlignment - Return the minimum known alignment in bytes of the
162   /// actual memory reference.
163   uint64_t getAlignment() const;
164 
165   /// getBaseAlignment - Return the minimum known alignment in bytes of the
166   /// base address, without the offset.
getBaseAlignment()167   uint64_t getBaseAlignment() const { return (1u << (Flags >> MOMaxBits)) >> 1; }
168 
169   /// getAAInfo - Return the AA tags for the memory reference.
getAAInfo()170   AAMDNodes getAAInfo() const { return AAInfo; }
171 
172   /// getRanges - Return the range tag for the memory reference.
getRanges()173   const MDNode *getRanges() const { return Ranges; }
174 
isLoad()175   bool isLoad() const { return Flags & MOLoad; }
isStore()176   bool isStore() const { return Flags & MOStore; }
isVolatile()177   bool isVolatile() const { return Flags & MOVolatile; }
isNonTemporal()178   bool isNonTemporal() const { return Flags & MONonTemporal; }
isInvariant()179   bool isInvariant() const { return Flags & MOInvariant; }
180 
181   /// isUnordered - Returns true if this memory operation doesn't have any
182   /// ordering constraints other than normal aliasing. Volatile and atomic
183   /// memory operations can't be reordered.
184   ///
185   /// Currently, we don't model the difference between volatile and atomic
186   /// operations. They should retain their ordering relative to all memory
187   /// operations.
isUnordered()188   bool isUnordered() const { return !isVolatile(); }
189 
190   /// refineAlignment - Update this MachineMemOperand to reflect the alignment
191   /// of MMO, if it has a greater alignment. This must only be used when the
192   /// new alignment applies to all users of this MachineMemOperand.
193   void refineAlignment(const MachineMemOperand *MMO);
194 
195   /// setValue - Change the SourceValue for this MachineMemOperand. This
196   /// should only be used when an object is being relocated and all references
197   /// to it are being updated.
setValue(const Value * NewSV)198   void setValue(const Value *NewSV) { PtrInfo.V = NewSV; }
setValue(const PseudoSourceValue * NewSV)199   void setValue(const PseudoSourceValue *NewSV) { PtrInfo.V = NewSV; }
setOffset(int64_t NewOffset)200   void setOffset(int64_t NewOffset) { PtrInfo.Offset = NewOffset; }
201 
202   /// Profile - Gather unique data for the object.
203   ///
204   void Profile(FoldingSetNodeID &ID) const;
205 
206   /// Support for operator<<.
207   /// @{
208   void print(raw_ostream &OS) const;
209   void print(raw_ostream &OS, ModuleSlotTracker &MST) const;
210   /// @}
211 
212   friend bool operator==(const MachineMemOperand &LHS,
213                          const MachineMemOperand &RHS) {
214     return LHS.getValue() == RHS.getValue() &&
215            LHS.getPseudoValue() == RHS.getPseudoValue() &&
216            LHS.getSize() == RHS.getSize() &&
217            LHS.getOffset() == RHS.getOffset() &&
218            LHS.getFlags() == RHS.getFlags() &&
219            LHS.getAAInfo() == RHS.getAAInfo() &&
220            LHS.getRanges() == RHS.getRanges() &&
221            LHS.getAlignment() == RHS.getAlignment() &&
222            LHS.getAddrSpace() == RHS.getAddrSpace();
223   }
224 
225   friend bool operator!=(const MachineMemOperand &LHS,
226                          const MachineMemOperand &RHS) {
227     return !(LHS == RHS);
228   }
229 };
230 
231 inline raw_ostream &operator<<(raw_ostream &OS, const MachineMemOperand &MRO) {
232   MRO.print(OS);
233   return OS;
234 }
235 
236 } // End llvm namespace
237 
238 #endif
239