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/DenseMap.h" 14#include "llvm/ADT/SmallVector.h" 15 16namespace llvm { 17class MCAssembler; 18class MCFragment; 19class MCSectionData; 20class MCSymbolData; 21 22/// Encapsulates the layout of an assembly file at a particular point in time. 23/// 24/// Assembly may requiring compute multiple layouts for a particular assembly 25/// file as part of the relaxation process. This class encapsulates the layout 26/// at a single point in time in such a way that it is always possible to 27/// efficiently compute the exact addresses of any symbol in the assembly file, 28/// even during the relaxation process. 29class MCAsmLayout { 30public: 31 typedef llvm::SmallVectorImpl<MCSectionData*>::const_iterator const_iterator; 32 typedef llvm::SmallVectorImpl<MCSectionData*>::iterator iterator; 33 34private: 35 MCAssembler &Assembler; 36 37 /// List of sections in layout order. 38 llvm::SmallVector<MCSectionData*, 16> SectionOrder; 39 40 /// The last fragment which was laid out, or 0 if nothing has been laid 41 /// out. Fragments are always laid out in order, so all fragments with a 42 /// lower ordinal will be up to date. 43 mutable DenseMap<const MCSectionData*, MCFragment *> LastValidFragment; 44 45 /// \brief Make sure that the layout for the given fragment is valid, lazily 46 /// computing it if necessary. 47 void EnsureValid(const MCFragment *F) const; 48 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 Invalidate all following fragments because a fragment has been 58 /// resized. The fragments size should have already been updated. 59 void Invalidate(MCFragment *F); 60 61 /// \brief Perform layout for a single fragment, assuming that the previous 62 /// fragment has already been laid out correctly, and the parent section has 63 /// been initialized. 64 void LayoutFragment(MCFragment *Fragment); 65 66 /// @name Section Access (in layout order) 67 /// @{ 68 69 llvm::SmallVectorImpl<MCSectionData*> &getSectionOrder() { 70 return SectionOrder; 71 } 72 const llvm::SmallVectorImpl<MCSectionData*> &getSectionOrder() const { 73 return SectionOrder; 74 } 75 76 /// @} 77 /// @name Fragment Layout Data 78 /// @{ 79 80 /// \brief Get the offset of the given fragment inside its containing section. 81 uint64_t getFragmentOffset(const MCFragment *F) const; 82 83 /// @} 84 /// @name Utility Functions 85 /// @{ 86 87 /// \brief Get the address space size of the given section, as it effects 88 /// layout. This may differ from the size reported by \see getSectionSize() by 89 /// not including section tail padding. 90 uint64_t getSectionAddressSize(const MCSectionData *SD) const; 91 92 /// \brief Get the data size of the given section, as emitted to the object 93 /// file. This may include additional padding, or be 0 for virtual sections. 94 uint64_t getSectionFileSize(const MCSectionData *SD) const; 95 96 /// \brief Get the offset of the given symbol, as computed in the current 97 /// layout. 98 uint64_t getSymbolOffset(const MCSymbolData *SD) const; 99 100 /// @} 101}; 102 103} // end namespace llvm 104 105#endif 106