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