MCSection.h revision f2dc4aa562e2478a73fe5aeeeec16b1e496a0642
1//===- MCSection.h - Machine Code Sections ----------------------*- 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 declares the MCSection class. 11// 12//===----------------------------------------------------------------------===// 13 14#ifndef LLVM_MC_MCSECTION_H 15#define LLVM_MC_MCSECTION_H 16 17#include <string> 18#include "llvm/ADT/StringRef.h" 19#include "llvm/MC/SectionKind.h" 20#include "llvm/Support/Casting.h" 21 22namespace llvm { 23 class MCContext; 24 class MCAsmInfo; 25 class raw_ostream; 26 27 /// MCSection - Instances of this class represent a uniqued identifier for a 28 /// section in the current translation unit. The MCContext class uniques and 29 /// creates these. 30 class MCSection { 31 public: 32 enum SectionVariant { 33 SV_COFF = 0, 34 SV_ELF, 35 SV_MachO 36 }; 37 38 private: 39 MCSection(const MCSection&); // DO NOT IMPLEMENT 40 void operator=(const MCSection&); // DO NOT IMPLEMENT 41 protected: 42 MCSection(SectionVariant V, SectionKind K) : Variant(V), Kind(K) {} 43 SectionVariant Variant; 44 SectionKind Kind; 45 public: 46 virtual ~MCSection(); 47 48 SectionKind getKind() const { return Kind; } 49 50 SectionVariant getVariant() const { return Variant; } 51 52 virtual void PrintSwitchToSection(const MCAsmInfo &MAI, 53 raw_ostream &OS) const = 0; 54 55 /// isBaseAddressKnownZero - Return true if we know that this section will 56 /// get a base address of zero. In cases where we know that this is true we 57 /// can emit section offsets as direct references to avoid a subtraction 58 /// from the base of the section, saving a relocation. 59 virtual bool isBaseAddressKnownZero() const { 60 return false; 61 } 62 63 // UseCodeAlign - Return true if a .align directive should use 64 // "optimized nops" to fill instead of 0s. 65 virtual bool UseCodeAlign() const = 0; 66 67 /// isVirtualSection - Check whether this section is "virtual", that is 68 /// has no actual object file contents. 69 virtual bool isVirtualSection() const = 0; 70 71 static bool classof(const MCSection *) { return true; } 72 }; 73 74} // end namespace llvm 75 76#endif 77