1 //===-- llvm/CodeGen/PseudoSourceValue.h ------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains the declaration of the PseudoSourceValue class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_CODEGEN_PSEUDOSOURCEVALUE_H
14 #define LLVM_CODEGEN_PSEUDOSOURCEVALUE_H
15 
16 #include "llvm/ADT/StringMap.h"
17 #include "llvm/IR/ValueMap.h"
18 #include <map>
19 
20 namespace llvm {
21 
22 class GlobalValue;
23 class MachineFrameInfo;
24 class MachineMemOperand;
25 class MIRFormatter;
26 class PseudoSourceValue;
27 class raw_ostream;
28 class TargetMachine;
29 
30 raw_ostream &operator<<(raw_ostream &OS, const PseudoSourceValue* PSV);
31 
32 /// Special value supplied for machine level alias analysis. It indicates that
33 /// a memory access references the functions stack frame (e.g., a spill slot),
34 /// below the stack frame (e.g., argument space), or constant pool.
35 class PseudoSourceValue {
36 public:
37   enum PSVKind : unsigned {
38     Stack,
39     GOT,
40     JumpTable,
41     ConstantPool,
42     FixedStack,
43     GlobalValueCallEntry,
44     ExternalSymbolCallEntry,
45     TargetCustom
46   };
47 
48 private:
49   unsigned Kind;
50   unsigned AddressSpace;
51   friend raw_ostream &llvm::operator<<(raw_ostream &OS,
52                                        const PseudoSourceValue* PSV);
53 
54   friend class MachineMemOperand; // For printCustom().
55   friend class MIRFormatter;      // For printCustom().
56 
57   /// Implement printing for PseudoSourceValue. This is called from
58   /// Value::print or Value's operator<<.
59   virtual void printCustom(raw_ostream &O) const;
60 
61 public:
62   explicit PseudoSourceValue(unsigned Kind, const TargetMachine &TM);
63 
64   virtual ~PseudoSourceValue();
65 
66   unsigned kind() const { return Kind; }
67 
68   bool isStack() const { return Kind == Stack; }
69   bool isGOT() const { return Kind == GOT; }
70   bool isConstantPool() const { return Kind == ConstantPool; }
71   bool isJumpTable() const { return Kind == JumpTable; }
72 
73   unsigned getAddressSpace() const { return AddressSpace; }
74 
75   unsigned getTargetCustom() const {
76     return (Kind >= TargetCustom) ? ((Kind+1) - TargetCustom) : 0;
77   }
78 
79   /// Test whether the memory pointed to by this PseudoSourceValue has a
80   /// constant value.
81   virtual bool isConstant(const MachineFrameInfo *) const;
82 
83   /// Test whether the memory pointed to by this PseudoSourceValue may also be
84   /// pointed to by an LLVM IR Value.
85   virtual bool isAliased(const MachineFrameInfo *) const;
86 
87   /// Return true if the memory pointed to by this PseudoSourceValue can ever
88   /// alias an LLVM IR Value.
89   virtual bool mayAlias(const MachineFrameInfo *) const;
90 };
91 
92 /// A specialized PseudoSourceValue for holding FixedStack values, which must
93 /// include a frame index.
94 class FixedStackPseudoSourceValue : public PseudoSourceValue {
95   const int FI;
96 
97 public:
98   explicit FixedStackPseudoSourceValue(int FI, const TargetMachine &TM)
99       : PseudoSourceValue(FixedStack, TM), FI(FI) {}
100 
101   static bool classof(const PseudoSourceValue *V) {
102     return V->kind() == FixedStack;
103   }
104 
105   bool isConstant(const MachineFrameInfo *MFI) const override;
106 
107   bool isAliased(const MachineFrameInfo *MFI) const override;
108 
109   bool mayAlias(const MachineFrameInfo *) const override;
110 
111   void printCustom(raw_ostream &OS) const override;
112 
113   int getFrameIndex() const { return FI; }
114 };
115 
116 class CallEntryPseudoSourceValue : public PseudoSourceValue {
117 protected:
118   CallEntryPseudoSourceValue(unsigned Kind, const TargetMachine &TM);
119 
120 public:
121   bool isConstant(const MachineFrameInfo *) const override;
122   bool isAliased(const MachineFrameInfo *) const override;
123   bool mayAlias(const MachineFrameInfo *) const override;
124 };
125 
126 /// A specialized pseudo source value for holding GlobalValue values.
127 class GlobalValuePseudoSourceValue : public CallEntryPseudoSourceValue {
128   const GlobalValue *GV;
129 
130 public:
131   GlobalValuePseudoSourceValue(const GlobalValue *GV, const TargetMachine &TM);
132 
133   static bool classof(const PseudoSourceValue *V) {
134     return V->kind() == GlobalValueCallEntry;
135   }
136 
137   const GlobalValue *getValue() const { return GV; }
138 };
139 
140 /// A specialized pseudo source value for holding external symbol values.
141 class ExternalSymbolPseudoSourceValue : public CallEntryPseudoSourceValue {
142   const char *ES;
143 
144 public:
145   ExternalSymbolPseudoSourceValue(const char *ES, const TargetMachine &TM);
146 
147   static bool classof(const PseudoSourceValue *V) {
148     return V->kind() == ExternalSymbolCallEntry;
149   }
150 
151   const char *getSymbol() const { return ES; }
152 };
153 
154 /// Manages creation of pseudo source values.
155 class PseudoSourceValueManager {
156   const TargetMachine &TM;
157   const PseudoSourceValue StackPSV, GOTPSV, JumpTablePSV, ConstantPoolPSV;
158   std::map<int, std::unique_ptr<FixedStackPseudoSourceValue>> FSValues;
159   StringMap<std::unique_ptr<const ExternalSymbolPseudoSourceValue>>
160       ExternalCallEntries;
161   ValueMap<const GlobalValue *,
162            std::unique_ptr<const GlobalValuePseudoSourceValue>>
163       GlobalCallEntries;
164 
165 public:
166   PseudoSourceValueManager(const TargetMachine &TM);
167 
168   /// Return a pseudo source value referencing the area below the stack frame of
169   /// a function, e.g., the argument space.
170   const PseudoSourceValue *getStack();
171 
172   /// Return a pseudo source value referencing the global offset table
173   /// (or something the like).
174   const PseudoSourceValue *getGOT();
175 
176   /// Return a pseudo source value referencing the constant pool. Since constant
177   /// pools are constant, this doesn't need to identify a specific constant
178   /// pool entry.
179   const PseudoSourceValue *getConstantPool();
180 
181   /// Return a pseudo source value referencing a jump table. Since jump tables
182   /// are constant, this doesn't need to identify a specific jump table.
183   const PseudoSourceValue *getJumpTable();
184 
185   /// Return a pseudo source value referencing a fixed stack frame entry,
186   /// e.g., a spill slot.
187   const PseudoSourceValue *getFixedStack(int FI);
188 
189   const PseudoSourceValue *getGlobalValueCallEntry(const GlobalValue *GV);
190 
191   const PseudoSourceValue *getExternalSymbolCallEntry(const char *ES);
192 };
193 
194 } // end namespace llvm
195 
196 #endif
197