include/llvm/MC/MCValue.h

   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
  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
  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