LLVM  10.0.0svn
MCValue.h
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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;
46  int64_t getConstant() const { return Cst; }
47  const MCSymbolRefExpr *getSymA() const { return SymA; }
48  const MCSymbolRefExpr *getSymB() const { return SymB; }
49  uint32_t getRefKind() const { return RefKind; }
50 
51  /// Is this an absolute (as opposed to relocatable) value.
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 
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 
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
This class represents lattice values for constants.
Definition: AllocatorList.h:23
This represents an "assembler immediate".
Definition: MCValue.h:39
bool isAbsolute() const
Is this an absolute (as opposed to relocatable) value.
Definition: MCValue.h:52
MCSymbolRefExpr::VariantKind getAccessVariant() const
Definition: MCValue.cpp:46
int64_t getConstant() const
Definition: MCValue.h:46
const MCSymbolRefExpr * getSymB() const
Definition: MCValue.h:48
Represent a reference to a symbol from inside an expression.
Definition: MCExpr.h:169
const MCSymbolRefExpr * getSymA() const
Definition: MCValue.h:47
MCValue()=default
void print(raw_ostream &OS) const
Print the value to the stream OS.
Definition: MCValue.cpp:18
uint32_t getRefKind() const
Definition: MCValue.h:49
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:45
void dump() const
Print the value to stderr.
Definition: MCValue.cpp:41