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 TargetInstrInfo;
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 TargetInstrInfo &TII);
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 TargetInstrInfo &TII)
99       : PseudoSourceValue(FixedStack, TII), 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 TargetInstrInfo &TII);
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,
132                                const TargetInstrInfo &TII);
133 
134   static bool classof(const PseudoSourceValue *V) {
135     return V->kind() == GlobalValueCallEntry;
136   }
137 
138   const GlobalValue *getValue() const { return GV; }
139 };
140 
141 /// A specialized pseudo source value for holding external symbol values.
142 class ExternalSymbolPseudoSourceValue : public CallEntryPseudoSourceValue {
143   const char *ES;
144 
145 public:
146   ExternalSymbolPseudoSourceValue(const char *ES, const TargetInstrInfo &TII);
147 
148   static bool classof(const PseudoSourceValue *V) {
149     return V->kind() == ExternalSymbolCallEntry;
150   }
151 
152   const char *getSymbol() const { return ES; }
153 };
154 
155 /// Manages creation of pseudo source values.
156 class PseudoSourceValueManager {
157   const TargetInstrInfo &TII;
158   const PseudoSourceValue StackPSV, GOTPSV, JumpTablePSV, ConstantPoolPSV;
159   std::map<int, std::unique_ptr<FixedStackPseudoSourceValue>> FSValues;
160   StringMap<std::unique_ptr<const ExternalSymbolPseudoSourceValue>>
161       ExternalCallEntries;
162   ValueMap<const GlobalValue *,
163            std::unique_ptr<const GlobalValuePseudoSourceValue>>
164       GlobalCallEntries;
165 
166 public:
167   PseudoSourceValueManager(const TargetInstrInfo &TII);
168 
169   /// Return a pseudo source value referencing the area below the stack frame of
170   /// a function, e.g., the argument space.
171   const PseudoSourceValue *getStack();
172 
173   /// Return a pseudo source value referencing the global offset table
174   /// (or something the like).
175   const PseudoSourceValue *getGOT();
176 
177   /// Return a pseudo source value referencing the constant pool. Since constant
178   /// pools are constant, this doesn't need to identify a specific constant
179   /// pool entry.
180   const PseudoSourceValue *getConstantPool();
181 
182   /// Return a pseudo source value referencing a jump table. Since jump tables
183   /// are constant, this doesn't need to identify a specific jump table.
184   const PseudoSourceValue *getJumpTable();
185 
186   /// Return a pseudo source value referencing a fixed stack frame entry,
187   /// e.g., a spill slot.
188   const PseudoSourceValue *getFixedStack(int FI);
189 
190   const PseudoSourceValue *getGlobalValueCallEntry(const GlobalValue *GV);
191 
192   const PseudoSourceValue *getExternalSymbolCallEntry(const char *ES);
193 };
194 
195 } // end namespace llvm
196 
197 #endif
198