1 //===- MCAsmLayout.h - Assembly Layout Object -------------------*- 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 #ifndef LLVM_MC_MCASMLAYOUT_H 11 #define LLVM_MC_MCASMLAYOUT_H 12 13 #include "llvm/ADT/SmallVector.h" 14 15 namespace llvm { 16 class MCAssembler; 17 class MCFragment; 18 class MCSectionData; 19 class MCSymbolData; 20 21 /// Encapsulates the layout of an assembly file at a particular point in time. 22 /// 23 /// Assembly may requiring compute multiple layouts for a particular assembly 24 /// file as part of the relaxation process. This class encapsulates the layout 25 /// at a single point in time in such a way that it is always possible to 26 /// efficiently compute the exact addresses of any symbol in the assembly file, 27 /// even during the relaxation process. 28 class MCAsmLayout { 29 public: 30 typedef llvm::SmallVectorImpl<MCSectionData*>::const_iterator const_iterator; 31 typedef llvm::SmallVectorImpl<MCSectionData*>::iterator iterator; 32 33 private: 34 MCAssembler &Assembler; 35 36 /// List of sections in layout order. 37 llvm::SmallVector<MCSectionData*, 16> SectionOrder; 38 39 /// The last fragment which was laid out, or 0 if nothing has been laid 40 /// out. Fragments are always laid out in order, so all fragments with a 41 /// lower ordinal will be up to date. 42 mutable DenseMap<const MCSectionData*, MCFragment *> LastValidFragment; 43 44 /// \brief Make sure that the layout for the given fragment is valid, lazily 45 /// computing it if necessary. 46 void EnsureValid(const MCFragment *F) const; 47 48 bool isFragmentUpToDate(const MCFragment *F) const; 49 50 public: 51 MCAsmLayout(MCAssembler &_Assembler); 52 53 /// Get the assembler object this is a layout for. 54 MCAssembler &getAssembler() const { return Assembler; } 55 56 /// \brief Invalidate all following fragments because a fragment has been 57 /// resized. The fragments size should have already been updated. 58 void Invalidate(MCFragment *F); 59 60 /// \brief Perform layout for a single fragment, assuming that the previous 61 /// fragment has already been laid out correctly, and the parent section has 62 /// been initialized. 63 void LayoutFragment(MCFragment *Fragment); 64 65 /// @name Section Access (in layout order) 66 /// @{ 67 68 llvm::SmallVectorImpl<MCSectionData*> &getSectionOrder() { 69 return SectionOrder; 70 } 71 const llvm::SmallVectorImpl<MCSectionData*> &getSectionOrder() const { 72 return SectionOrder; 73 } 74 75 /// @} 76 /// @name Fragment Layout Data 77 /// @{ 78 79 /// \brief Get the offset of the given fragment inside its containing section. 80 uint64_t getFragmentOffset(const MCFragment *F) const; 81 82 /// @} 83 /// @name Utility Functions 84 /// @{ 85 86 /// \brief Get the address space size of the given section, as it effects 87 /// layout. This may differ from the size reported by \see getSectionSize() by 88 /// not including section tail padding. 89 uint64_t getSectionAddressSize(const MCSectionData *SD) const; 90 91 /// \brief Get the data size of the given section, as emitted to the object 92 /// file. This may include additional padding, or be 0 for virtual sections. 93 uint64_t getSectionFileSize(const MCSectionData *SD) const; 94 95 /// \brief Get the offset of the given symbol, as computed in the current 96 /// layout. 97 uint64_t getSymbolOffset(const MCSymbolData *SD) const; 98 99 /// @} 100 }; 101 102 } // end namespace llvm 103 104 #endif 105
