1 //===- ELFAttributeData.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_TARGET_ELFATTRIBUTEDATA_H 10 #define MCLD_TARGET_ELFATTRIBUTEDATA_H 11 12 #include <stdint.h> 13 #include <string> 14 #include <utility> 15 16 namespace mcld { 17 18 class ELFAttributeValue; 19 class Input; 20 class LinkerConfig; 21 22 /** \class ELFAttributeData 23 * \brief ELFAttributeData handles data in vendor attribute subsection. 24 */ 25 class ELFAttributeData 26 { 27 public: 28 typedef uint32_t TagType; 29 30 // Generic attribute tags shared between all vendors 31 enum { 32 Tag_NULL = 0, 33 Tag_File = 1, 34 Tag_Section = 2, 35 Tag_Symbol = 3, 36 }; 37 38 public: ELFAttributeData(const char * pVendor)39 ELFAttributeData(const char* pVendor) : m_Vendor(pVendor) { } 40 ~ELFAttributeData()41 virtual ~ELFAttributeData() { } 42 43 public: getVendorName()44 inline const std::string &getVendorName() const { return m_Vendor; } 45 46 /// getAttributeValue - query the data store for the attribute value of the 47 /// given tag. 48 virtual const ELFAttributeValue *getAttributeValue(TagType pTag) const = 0; 49 50 /// getOrCreateAttributeValue - obtain attribute value for the given tag and 51 /// create if it does not exist. 52 /// 53 /// It returns a pair containing the attribute value instance (guaranteed to 54 /// be non-NULL) and a boolean value indicating whether the instance is newly 55 /// created (true) or not (false.) 56 virtual std::pair<ELFAttributeValue*, bool> 57 getOrCreateAttributeValue(TagType pTag) = 0; 58 59 /// preMerge - hooks to call before starting merge the attribute data in an 60 /// input. preMerge(const Input & pInput)61 virtual bool preMerge(const Input &pInput) { return true; } 62 63 /// merge - implement logics to merge input attribute to the output. 64 virtual bool merge(const LinkerConfig& pConfig, const Input &pInput, 65 TagType pTag, const ELFAttributeValue& pInAttr) = 0; 66 67 /// postMerge - hooks to call after finishing merge the attribute data from an 68 /// input. postMerge(const LinkerConfig & pConfig,const Input & pInput)69 virtual bool postMerge(const LinkerConfig& pConfig, const Input &pInput) 70 { return true; } 71 72 /// sizeOutput - obtain number of bytes required to encode the attribute data. 73 virtual size_t sizeOutput() const = 0; 74 75 /// emit - write out attribute data to the buffer and return the number of 76 /// bytes written 77 virtual size_t emit(char *pBuf) const = 0; 78 79 public: 80 /// ReadTag - read an attribute tag from input buffer. 81 /// 82 /// If the read succeeds, pBuf moves to the new position just pass the end of 83 /// the tag in the buffer and pBufSize decreases the size of tag in the 84 /// buffer. Otherwise, this function will return false and change nothing 85 /// except leaving undefined value in pTag. 86 static bool ReadTag(TagType& pTag, const char* &pBuf, size_t &pBufSize); 87 88 /// ReadValue - read an attribute value from input buffer 89 /// 90 /// Similar with ReadTag() while this reads attribute value from the input 91 /// buffer. Note that the value type of the attribute must be properly set in 92 /// pValue prior the call. 93 static bool ReadValue(ELFAttributeValue& pValue, const char* &pBuf, 94 size_t &pBufSize); 95 96 /// WriteAttribute - write an attribute tag plus value to buffer. 97 /// 98 /// On success, the pBuf moves to the new position just pass the end of the 99 /// attribute data just written. Otherwise, it returns false and leaves pBuf 100 /// in an undefined position. Note that buffer is guaranteed to be able to 101 /// contain the attribute data. 102 static bool WriteAttribute(TagType pTag, const ELFAttributeValue& pValue, 103 char* &pBuf); 104 105 private: 106 const std::string m_Vendor; 107 }; 108 109 } // namespace of mcld 110 111 #endif 112