1 //===-- llvm/MC/MCValue.h - MCValue class -----------------------*- 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 MCValue class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_MC_MCVALUE_H
14 #define LLVM_MC_MCVALUE_H
15 
16 #include "llvm/MC/MCExpr.h"
17 #include "llvm/Support/DataTypes.h"
18 
19 namespace llvm {
20 class raw_ostream;
21 
22 /// This represents an "assembler immediate".
23 ///
24 ///  In its most general form, this can hold ":Kind:(SymbolA - SymbolB +
25 ///  imm64)".  Not all targets supports relocations of this general form, but we
26 ///  need to represent this anyway.
27 ///
28 /// In general both SymbolA and SymbolB will also have a modifier
29 /// analogous to the top-level Kind. Current targets are not expected
30 /// to make use of both though. The choice comes down to whether
31 /// relocation modifiers apply to the closest symbol or the whole
32 /// expression.
33 ///
34 /// Note that this class must remain a simple POD value class, because we need
35 /// it to live in unions etc.
36 class MCValue {
37   const MCSymbolRefExpr *SymA = nullptr, *SymB = nullptr;
38   int64_t Cst = 0;
39   uint32_t RefKind = 0;
40 
41 public:
42   MCValue() = default;
43   int64_t getConstant() const { return Cst; }
44   const MCSymbolRefExpr *getSymA() const { return SymA; }
45   const MCSymbolRefExpr *getSymB() const { return SymB; }
46   uint32_t getRefKind() const { return RefKind; }
47 
48   /// Is this an absolute (as opposed to relocatable) value.
49   bool isAbsolute() const { return !SymA && !SymB; }
50 
51   /// Print the value to the stream \p OS.
52   void print(raw_ostream &OS) const;
53 
54   /// Print the value to stderr.
55   void dump() const;
56 
57   MCSymbolRefExpr::VariantKind getAccessVariant() const;
58 
59   static MCValue get(const MCSymbolRefExpr *SymA,
60                      const MCSymbolRefExpr *SymB = nullptr,
61                      int64_t Val = 0, uint32_t RefKind = 0) {
62     MCValue R;
63     R.Cst = Val;
64     R.SymA = SymA;
65     R.SymB = SymB;
66     R.RefKind = RefKind;
67     return R;
68   }
69 
70   static MCValue get(int64_t Val) {
71     MCValue R;
72     R.Cst = Val;
73     R.SymA = nullptr;
74     R.SymB = nullptr;
75     R.RefKind = 0;
76     return R;
77   }
78 
79 };
80 
81 } // end namespace llvm
82 
83 #endif
84