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