MCAsmLayout.h revision 0e11dfc4a6f7e3a3d3bc0365e1da43bc2fa0aac2
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 /// \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 isSectionUpToDate(const MCSectionData *SD) const; 49 bool isFragmentUpToDate(const MCFragment *F) const; 50 51public: 52 MCAsmLayout(MCAssembler &_Assembler); 53 54 /// Get the assembler object this is a layout for. 55 MCAssembler &getAssembler() const { return Assembler; } 56 57 /// \brief Update the layout because a fragment has been resized. The 58 /// fragments size should have already been updated, the \arg SlideAmount is 59 /// the delta from the old size. 60 void UpdateForSlide(MCFragment *F, int SlideAmount); 61 62 /// \brief Update the layout, replacing Src with Dst. The contents 63 /// of Src and Dst are not modified, and must be copied by the caller. 64 /// Src will be removed from the layout, but not deleted. 65 void ReplaceFragment(MCFragment *Src, MCFragment *Dst); 66 67 /// \brief Update the layout to coalesce Src into Dst. The contents 68 /// of Src and Dst are not modified, and must be coalesced by the caller. 69 /// Src will be removed from the layout, but not deleted. 70 void CoalesceFragments(MCFragment *Src, MCFragment *Dst); 71 72 /// \brief Perform a full layout. 73 void LayoutFile(); 74 75 /// \brief Perform layout for a single fragment, assuming that the previous 76 /// fragment has already been layed out correctly, and the parent section has 77 /// been initialized. 78 void LayoutFragment(MCFragment *Fragment); 79 80 /// \brief Performs initial layout for a single section, assuming that the 81 /// previous section (including its fragments) has already been layed out 82 /// correctly. 83 void LayoutSection(MCSectionData *SD); 84 85 /// @name Section Access (in layout order) 86 /// @{ 87 88 llvm::SmallVectorImpl<MCSectionData*> &getSectionOrder() { 89 return SectionOrder; 90 } 91 const llvm::SmallVectorImpl<MCSectionData*> &getSectionOrder() const { 92 return SectionOrder; 93 } 94 95 /// @} 96 /// @name Fragment Layout Data 97 /// @{ 98 99 /// \brief Get the effective size of the given fragment, as computed in the 100 /// current layout. 101 uint64_t getFragmentEffectiveSize(const MCFragment *F) const; 102 103 /// \brief Get the offset of the given fragment inside its containing section. 104 uint64_t getFragmentOffset(const MCFragment *F) const; 105 106 /// @} 107 /// @name Section Layout Data 108 /// @{ 109 110 /// \brief Get the computed address of the given section. 111 uint64_t getSectionAddress(const MCSectionData *SD) const; 112 113 /// @} 114 /// @name Utility Functions 115 /// @{ 116 117 /// \brief Get the address of the given fragment, as computed in the current 118 /// layout. 119 uint64_t getFragmentAddress(const MCFragment *F) const; 120 121 /// \brief Get the address space size of the given section, as it effects 122 /// layout. This may differ from the size reported by \see getSectionSize() by 123 /// not including section tail padding. 124 uint64_t getSectionAddressSize(const MCSectionData *SD) const; 125 126 /// \brief Get the data size of the given section, as emitted to the object 127 /// file. This may include additional padding, or be 0 for virtual sections. 128 uint64_t getSectionFileSize(const MCSectionData *SD) const; 129 130 /// \brief Get the logical data size of the given section. 131 uint64_t getSectionSize(const MCSectionData *SD) const; 132 133 /// \brief Get the address of the given symbol, as computed in the current 134 /// layout. 135 uint64_t getSymbolAddress(const MCSymbolData *SD) const; 136 137 /// @} 138}; 139 140} // end namespace llvm 141 142#endif 143