1 //===- GarbageCollection.h ------------------------------------------------===// 2 // 3 // The MCLinker Project 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 #ifndef MCLD_LD_GARBAGECOLLECTION_H 10 #define MCLD_LD_GARBAGECOLLECTION_H 11 12 #include <map> 13 #include <set> 14 #include <vector> 15 16 namespace mcld { 17 18 class LDSection; 19 class LinkerConfig; 20 class Module; 21 class TargetLDBackend; 22 23 /** \class GarbageCollection 24 * \brief Implementation of garbage collection for --gc-section. 25 * @ref GNU gold, gc. 26 */ 27 class GarbageCollection 28 { 29 public: 30 typedef std::set<const LDSection*> SectionListTy; 31 typedef std::vector<const LDSection*> SectionVecTy; 32 33 /** \class SectionReachedListMap 34 * \brief Map the section to the list of sections which it can reach directly 35 */ 36 class SectionReachedListMap 37 { 38 public: 39 SectionReachedListMap() {} 40 41 /// addReference - add a reference from pFrom to pTo 42 void addReference(const LDSection& pFrom, const LDSection& pTo); 43 44 /// getReachedList - get the list of sections which can be reached by 45 /// pSection, create one if the list has not existed 46 SectionListTy& getReachedList(const LDSection& pSection); 47 48 /// findReachedList - find the list of sections which can be reached by 49 /// pSection, return NULL if the list not exists 50 SectionListTy* findReachedList(const LDSection& pSection); 51 52 private: 53 typedef std::map<const LDSection*, SectionListTy> ReachedSectionsTy; 54 55 private: 56 /// m_ReachedSections - map a section to the reachable sections list 57 ReachedSectionsTy m_ReachedSections; 58 }; 59 60 public: 61 GarbageCollection(const LinkerConfig& pConfig, 62 const TargetLDBackend& pBackend, 63 Module& pModule); 64 ~GarbageCollection(); 65 66 /// run - do garbage collection 67 bool run(); 68 69 private: 70 void setUpReachedSections(); 71 void findReferencedSections(SectionVecTy& pEntry); 72 void getEntrySections(SectionVecTy& pEntry); 73 void stripSections(); 74 75 private: 76 /// m_SectionReachedListMap - map the section to the list of sections which it 77 /// can reach directly 78 SectionReachedListMap m_SectionReachedListMap; 79 80 /// m_ReferencedSections - a list of sections which can be reached from entry 81 SectionListTy m_ReferencedSections; 82 83 const LinkerConfig& m_Config; 84 const TargetLDBackend& m_Backend; 85 Module& m_Module; 86 }; 87 88 } // namespace of mcld 89 90 #endif 91 92
