1 //===-- llvm/MC/MCValue.h - MCValue 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 MCValue class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_MC_MCVALUE_H
15 #define LLVM_MC_MCVALUE_H
16 
17 #include "llvm/MC/MCExpr.h"
18 #include "llvm/MC/MCSymbol.h"
19 #include "llvm/Support/DataTypes.h"
20 #include <cassert>
21 
22 namespace llvm {
23 class MCAsmInfo;
24 class raw_ostream;
25 
26 /// This represents an "assembler immediate".
27 ///
28 ///  In its most general form, this can hold ":Kind:(SymbolA - SymbolB +
29 ///  imm64)".  Not all targets supports relocations of this general form, but we
30 ///  need to represent this anyway.
31 ///
32 /// In general both SymbolA and SymbolB will also have a modifier
33 /// analogous to the top-level Kind. Current targets are not expected
34 /// to make use of both though. The choice comes down to whether
35 /// relocation modifiers apply to the closest symbol or the whole
36 /// expression.
37 ///
38 /// Note that this class must remain a simple POD value class, because we need
39 /// it to live in unions etc.
40 class MCValue {
41   const MCSymbolRefExpr *SymA = nullptr, *SymB = nullptr;
42   int64_t Cst = 0;
43   uint32_t RefKind = 0;
44 
45 public:
46   MCValue() = default;
getConstant()47   int64_t getConstant() const { return Cst; }
getSymA()48   const MCSymbolRefExpr *getSymA() const { return SymA; }
getSymB()49   const MCSymbolRefExpr *getSymB() const { return SymB; }
getRefKind()50   uint32_t getRefKind() const { return RefKind; }
51 
52   /// Is this an absolute (as opposed to relocatable) value.
isAbsolute()53   bool isAbsolute() const { return !SymA && !SymB; }
54 
55   /// Print the value to the stream \p OS.
56   void print(raw_ostream &OS) const;
57 
58   /// Print the value to stderr.
59   void dump() const;
60 
61   MCSymbolRefExpr::VariantKind getAccessVariant() const;
62 
63   static MCValue get(const MCSymbolRefExpr *SymA,
64                      const MCSymbolRefExpr *SymB = nullptr,
65                      int64_t Val = 0, uint32_t RefKind = 0) {
66     MCValue R;
67     R.Cst = Val;
68     R.SymA = SymA;
69     R.SymB = SymB;
70     R.RefKind = RefKind;
71     return R;
72   }
73 
get(int64_t Val)74   static MCValue get(int64_t Val) {
75     MCValue R;
76     R.Cst = Val;
77     R.SymA = nullptr;
78     R.SymB = nullptr;
79     R.RefKind = 0;
80     return R;
81   }
82 
83 };
84 
85 } // end namespace llvm
86 
87 #endif
88