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 public: 27 typedef uint32_t TagType; 28 29 // Generic attribute tags shared between all vendors 30 enum { 31 Tag_NULL = 0, 32 Tag_File = 1, 33 Tag_Section = 2, 34 Tag_Symbol = 3, 35 }; 36 37 public: 38 explicit ELFAttributeData(const char* pVendor) : m_Vendor(pVendor) {} 39 40 virtual ~ELFAttributeData() {} 41 42 public: 43 inline const std::string& getVendorName() const { return m_Vendor; } 44 45 /// getAttributeValue - query the data store for the attribute value of the 46 /// given tag. 47 virtual const ELFAttributeValue* getAttributeValue(TagType pTag) const = 0; 48 49 /// getOrCreateAttributeValue - obtain attribute value for the given tag and 50 /// create if it does not exist. 51 /// 52 /// It returns a pair containing the attribute value instance (guaranteed to 53 /// be non-NULL) and a boolean value indicating whether the instance is newly 54 /// created (true) or not (false.) 55 virtual std::pair<ELFAttributeValue*, bool> getOrCreateAttributeValue( 56 TagType pTag) = 0; 57 58 /// preMerge - hooks to call before starting merge the attribute data in an 59 /// input. 60 virtual bool preMerge(const Input& pInput) { return true; } 61 62 /// merge - implement logics to merge input attribute to the output. 63 virtual bool merge(const LinkerConfig& pConfig, 64 const Input& pInput, 65 TagType pTag, 66 const ELFAttributeValue& pInAttr) = 0; 67 68 /// postMerge - hooks to call after finishing merge the attribute data from an 69 /// input. 70 virtual bool postMerge(const LinkerConfig& pConfig, const Input& pInput) { 71 return true; 72 } 73 74 /// sizeOutput - obtain number of bytes required to encode the attribute data. 75 virtual size_t sizeOutput() const = 0; 76 77 /// emit - write out attribute data to the buffer and return the number of 78 /// bytes written 79 virtual size_t emit(char* pBuf) const = 0; 80 81 public: 82 /// ReadTag - read an attribute tag from input buffer. 83 /// 84 /// If the read succeeds, pBuf moves to the new position just pass the end of 85 /// the tag in the buffer and pBufSize decreases the size of tag in the 86 /// buffer. Otherwise, this function will return false and change nothing 87 /// except leaving undefined value in pTag. 88 static bool ReadTag(TagType& pTag, const char*& pBuf, size_t& pBufSize); 89 90 /// ReadValue - read an attribute value from input buffer 91 /// 92 /// Similar with ReadTag() while this reads attribute value from the input 93 /// buffer. Note that the value type of the attribute must be properly set in 94 /// pValue prior the call. 95 static bool ReadValue(ELFAttributeValue& pValue, 96 const char*& pBuf, 97 size_t& pBufSize); 98 99 /// WriteAttribute - write an attribute tag plus value to buffer. 100 /// 101 /// On success, the pBuf moves to the new position just pass the end of the 102 /// attribute data just written. Otherwise, it returns false and leaves pBuf 103 /// in an undefined position. Note that buffer is guaranteed to be able to 104 /// contain the attribute data. 105 static bool WriteAttribute(TagType pTag, 106 const ELFAttributeValue& pValue, 107 char*& pBuf); 108 109 private: 110 const std::string m_Vendor; 111 }; 112 113 } // namespace mcld 114 115 #endif // MCLD_TARGET_ELFATTRIBUTEDATA_H_ 116
