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 22 namespace llvm { 23 class MCAsmInfo; 24 class raw_ostream; 25 26 /// \brief This represents an "assembler immediate". 27 /// 28 /// In its most general form, this can hold ":Kind:(SymbolA - SymbolB + 29 /// imm64)". Not all targets supports relocations of this general form, but we 30 /// need to represent this anyway. 31 /// 32 /// In general both SymbolA and SymbolB will also have a modifier 33 /// analogous to the top-level Kind. Current targets are not expected 34 /// to make use of both though. The choice comes down to whether 35 /// relocation modifiers apply to the closest symbol or the whole 36 /// expression. 37 /// 38 /// In the general form, SymbolB can only be defined if SymbolA is, and both 39 /// must be in the same (non-external) section. The latter constraint is not 40 /// enforced, since a symbol's section may not be known at construction. 41 /// 42 /// Note that this class must remain a simple POD value class, because we need 43 /// it to live in unions etc. 44 class MCValue { 45 const MCSymbolRefExpr *SymA, *SymB; 46 int64_t Cst; 47 uint32_t RefKind; 48 public: 49 getConstant()50 int64_t getConstant() const { return Cst; } getSymA()51 const MCSymbolRefExpr *getSymA() const { return SymA; } getSymB()52 const MCSymbolRefExpr *getSymB() const { return SymB; } getRefKind()53 uint32_t getRefKind() const { return RefKind; } 54 55 /// \brief Is this an absolute (as opposed to relocatable) value. isAbsolute()56 bool isAbsolute() const { return !SymA && !SymB; } 57 58 /// \brief Print the value to the stream \p OS. 59 void print(raw_ostream &OS) const; 60 61 /// \brief Print the value to stderr. 62 void dump() const; 63 64 MCSymbolRefExpr::VariantKind getAccessVariant() const; 65 66 static MCValue get(const MCSymbolRefExpr *SymA, 67 const MCSymbolRefExpr *SymB = nullptr, 68 int64_t Val = 0, uint32_t RefKind = 0) { 69 MCValue R; 70 assert((!SymB || SymA) && "Invalid relocatable MCValue!"); 71 R.Cst = Val; 72 R.SymA = SymA; 73 R.SymB = SymB; 74 R.RefKind = RefKind; 75 return R; 76 } 77 get(int64_t Val)78 static MCValue get(int64_t Val) { 79 MCValue R; 80 R.Cst = Val; 81 R.SymA = nullptr; 82 R.SymB = nullptr; 83 R.RefKind = 0; 84 return R; 85 } 86 87 }; 88 89 } // end namespace llvm 90 91 #endif 92