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
22namespace llvm {
23class MCAsmInfo;
24class raw_ostream;
25
26/// MCValue - This represents an "assembler immediate".  In its most
27/// general form, this can hold ":Kind:(SymbolA - SymbolB + imm64)".
28/// 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/// In the general form, SymbolB can only be defined if SymbolA is, and both
38/// must be in the same (non-external) section. The latter constraint is not
39/// enforced, since a symbol's section may not be known at construction.
40///
41/// Note that this class must remain a simple POD value class, because we need
42/// it to live in unions etc.
43class MCValue {
44  const MCSymbolRefExpr *SymA, *SymB;
45  int64_t Cst;
46  uint32_t RefKind;
47public:
48
49  int64_t getConstant() const { return Cst; }
50  const MCSymbolRefExpr *getSymA() const { return SymA; }
51  const MCSymbolRefExpr *getSymB() const { return SymB; }
52  uint32_t getRefKind() const { return RefKind; }
53
54  /// isAbsolute - Is this an absolute (as opposed to relocatable) value.
55  bool isAbsolute() const { return !SymA && !SymB; }
56
57  /// print - Print the value to the stream \p OS.
58  void print(raw_ostream &OS, const MCAsmInfo *MAI) const;
59
60  /// dump - Print the value to stderr.
61  void dump() const;
62
63  MCSymbolRefExpr::VariantKind getAccessVariant() const;
64
65  static MCValue get(const MCSymbolRefExpr *SymA,
66                     const MCSymbolRefExpr *SymB = nullptr,
67                     int64_t Val = 0, uint32_t RefKind = 0) {
68    MCValue R;
69    assert((!SymB || SymA) && "Invalid relocatable MCValue!");
70    R.Cst = Val;
71    R.SymA = SymA;
72    R.SymB = SymB;
73    R.RefKind = RefKind;
74    return R;
75  }
76
77  static MCValue get(int64_t Val) {
78    MCValue R;
79    R.Cst = Val;
80    R.SymA = nullptr;
81    R.SymB = nullptr;
82    R.RefKind = 0;
83    return R;
84  }
85
86};
87
88} // end namespace llvm
89
90#endif
91