MCAsmLayout.h revision 9005d45a990ef46f06800bd6bd6a7d1298a33645
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 15namespace llvm { 16class MCAssembler; 17class MCFragment; 18class MCSectionData; 19class 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. 28class MCAsmLayout { 29public: 30 typedef llvm::SmallVectorImpl<MCSectionData*>::const_iterator const_iterator; 31 typedef llvm::SmallVectorImpl<MCSectionData*>::iterator iterator; 32 33private: 34 MCAssembler &Assembler; 35 36 /// List of sections in layout order. 37 llvm::SmallVector<MCSectionData*, 16> SectionOrder; 38 39 /// The last fragment which was layed out, or 0 if nothing has been layed 40 /// out. Fragments are always layed out in order, so all fragments with a 41 /// lower ordinal will be up to date. 42 mutable MCFragment *LastValidFragment; 43 44 bool isSectionUpToDate(const MCSectionData *SD) const; 45 bool isFragmentUpToDate(const MCFragment *F) const; 46 47public: 48 MCAsmLayout(MCAssembler &_Assembler); 49 50 /// Get the assembler object this is a layout for. 51 MCAssembler &getAssembler() const { return Assembler; } 52 53 /// \brief Update the layout because a fragment has been resized. The 54 /// fragments size should have already been updated, the \arg SlideAmount is 55 /// the delta from the old size. 56 void UpdateForSlide(MCFragment *F, int SlideAmount); 57 58 /// \brief Update the layout because a fragment has been replaced. 59 void FragmentReplaced(MCFragment *Src, MCFragment *Dst); 60 61 /// \brief Perform a full layout. 62 void LayoutFile(); 63 64 /// \brief Perform layout for a single fragment, assuming that the previous 65 /// fragment has already been layed out correctly, and the parent section has 66 /// been initialized. 67 void LayoutFragment(MCFragment *Fragment); 68 69 /// \brief Performs initial layout for a single section, assuming that the 70 /// previous section (including its fragments) has already been layed out 71 /// correctly. 72 void LayoutSection(MCSectionData *SD); 73 74 /// @name Section Access (in layout order) 75 /// @{ 76 77 llvm::SmallVectorImpl<MCSectionData*> &getSectionOrder() { 78 return SectionOrder; 79 } 80 const llvm::SmallVectorImpl<MCSectionData*> &getSectionOrder() const { 81 return SectionOrder; 82 } 83 84 /// @} 85 /// @name Fragment Layout Data 86 /// @{ 87 88 /// \brief Get the effective size of the given fragment, as computed in the 89 /// current layout. 90 uint64_t getFragmentEffectiveSize(const MCFragment *F) const; 91 92 /// \brief Get the offset of the given fragment inside its containing section. 93 uint64_t getFragmentOffset(const MCFragment *F) const; 94 95 /// @} 96 /// @name Section Layout Data 97 /// @{ 98 99 /// \brief Get the computed address of the given section. 100 uint64_t getSectionAddress(const MCSectionData *SD) const; 101 102 /// @} 103 /// @name Utility Functions 104 /// @{ 105 106 /// \brief Get the address of the given fragment, as computed in the current 107 /// layout. 108 uint64_t getFragmentAddress(const MCFragment *F) const; 109 110 /// \brief Get the address space size of the given section, as it effects 111 /// layout. This may differ from the size reported by \see getSectionSize() by 112 /// not including section tail padding. 113 uint64_t getSectionAddressSize(const MCSectionData *SD) const; 114 115 /// \brief Get the data size of the given section, as emitted to the object 116 /// file. This may include additional padding, or be 0 for virtual sections. 117 uint64_t getSectionFileSize(const MCSectionData *SD) const; 118 119 /// \brief Get the logical data size of the given section. 120 uint64_t getSectionSize(const MCSectionData *SD) const; 121 122 /// \brief Get the address of the given symbol, as computed in the current 123 /// layout. 124 uint64_t getSymbolAddress(const MCSymbolData *SD) const; 125 126 /// @} 127}; 128 129} // end namespace llvm 130 131#endif 132