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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/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;
     44   int64_t getConstant() const { return Cst; }
     45   const MCSymbolRefExpr *getSymA() const { return SymA; }
     46   const MCSymbolRefExpr *getSymB() const { return SymB; }
     47   uint32_t getRefKind() const { return RefKind; }
     48 
     49   /// Is this an absolute (as opposed to relocatable) value.
     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 
     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