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 "llvm/ADT/StringRef.h" 18 #include "llvm/MC/SectionKind.h" 19 #include "llvm/Support/Compiler.h" 20 21 namespace llvm { 22 class MCAsmInfo; 23 class MCExpr; 24 class raw_ostream; 25 26 /// MCSection - Instances of this class represent a uniqued identifier for a 27 /// section in the current translation unit. The MCContext class uniques and 28 /// creates these. 29 class MCSection { 30 public: 31 enum SectionVariant { 32 SV_COFF = 0, 33 SV_ELF, 34 SV_MachO, 35 SV_LDContext 36 }; 37 38 private: 39 MCSection(const MCSection&) LLVM_DELETED_FUNCTION; 40 void operator=(const MCSection&) LLVM_DELETED_FUNCTION; 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, 54 const MCExpr *Subsection) const = 0; 55 56 // Convenience routines to get label names for the beginning/end of a 57 // section. 58 virtual std::string getLabelBeginName() const = 0; 59 virtual std::string getLabelEndName() const = 0; 60 61 /// isBaseAddressKnownZero - Return true if we know that this section will 62 /// get a base address of zero. In cases where we know that this is true we 63 /// can emit section offsets as direct references to avoid a subtraction 64 /// from the base of the section, saving a relocation. 65 virtual bool isBaseAddressKnownZero() const { 66 return false; 67 } 68 69 // UseCodeAlign - Return true if a .align directive should use 70 // "optimized nops" to fill instead of 0s. 71 virtual bool UseCodeAlign() const = 0; 72 73 /// isVirtualSection - Check whether this section is "virtual", that is 74 /// has no actual object file contents. 75 virtual bool isVirtualSection() const = 0; 76 }; 77 78 } // end namespace llvm 79 80 #endif 81
