| // merge.h -- handle section merging for gold -*- C++ -*- |
| |
| #ifndef GOLD_MERGE_H |
| #define GOLD_MERGE_H |
| |
| #include <climits> |
| |
| #include "stringpool.h" |
| #include "output.h" |
| |
| namespace gold |
| { |
| |
| // A general class for SHF_MERGE data, to hold functions shared by |
| // fixed-size constant data and string data. |
| |
| class Output_merge_base : public Output_section_data |
| { |
| public: |
| Output_merge_base(uint64_t entsize) |
| : Output_section_data(1), merge_map_(), entsize_(entsize) |
| { } |
| |
| // Return the output address for an input address. |
| bool |
| do_output_address(const Relobj* object, unsigned int shndx, off_t offset, |
| uint64_t output_section_address, uint64_t* poutput) const; |
| |
| protected: |
| // Return the entry size. |
| uint64_t |
| entsize() const |
| { return this->entsize_; } |
| |
| // Add a mapping from an OFFSET in input section SHNDX in object |
| // OBJECT to an OUTPUT_OFFSET in the output section. |
| void |
| add_mapping(Relobj* object, unsigned int shndx, off_t offset, |
| off_t output_offset); |
| |
| private: |
| // We build a mapping from OBJECT/SHNDX/OFFSET to an offset in the |
| // output section. |
| struct Merge_key |
| { |
| const Relobj* object; |
| unsigned int shndx; |
| off_t offset; |
| }; |
| |
| struct Merge_key_less |
| { |
| bool |
| operator()(const Merge_key&, const Merge_key&) const; |
| }; |
| |
| typedef std::map<Merge_key, off_t, Merge_key_less> Merge_map; |
| |
| // A mapping from input object/section/offset to offset in output |
| // section. |
| Merge_map merge_map_; |
| |
| // The entry size. For fixed-size constants, this is the size of |
| // the constants. For strings, this is the size of a character. |
| uint64_t entsize_; |
| }; |
| |
| // Handle SHF_MERGE sections with fixed-size constant data. |
| |
| class Output_merge_data : public Output_merge_base |
| { |
| public: |
| Output_merge_data(uint64_t entsize) |
| : Output_merge_base(entsize), p_(NULL), len_(0), alc_(0), |
| hashtable_(128, Merge_data_hash(this), Merge_data_eq(this)) |
| { } |
| |
| // Add an input section. |
| bool |
| do_add_input_section(Relobj* object, unsigned int shndx); |
| |
| // Set the final data size. |
| void |
| do_set_address(uint64_t, off_t); |
| |
| // Write the data to the file. |
| void |
| do_write(Output_file*); |
| |
| private: |
| // We build a hash table of the fixed-size constants. Each constant |
| // is stored as a pointer into the section data we are accumulating. |
| |
| // A key in the hash table. This is an offset in the section |
| // contents we are building. |
| typedef off_t Merge_data_key; |
| |
| // Compute the hash code. To do this we need a pointer back to the |
| // object holding the data. |
| class Merge_data_hash |
| { |
| public: |
| Merge_data_hash(const Output_merge_data* pomd) |
| : pomd_(pomd) |
| { } |
| |
| size_t |
| operator()(Merge_data_key) const; |
| |
| private: |
| const Output_merge_data* pomd_; |
| }; |
| |
| friend class Merge_data_hash; |
| |
| // Compare two entries in the hash table for equality. To do this |
| // we need a pointer back to the object holding the data. Note that |
| // we now have a pointer to the object stored in two places in the |
| // hash table. Fixing this would require specializing the hash |
| // table, which would be hard to do portably. |
| class Merge_data_eq |
| { |
| public: |
| Merge_data_eq(const Output_merge_data* pomd) |
| : pomd_(pomd) |
| { } |
| |
| bool |
| operator()(Merge_data_key k1, Merge_data_key k2) const; |
| |
| private: |
| const Output_merge_data* pomd_; |
| }; |
| |
| friend class Merge_data_eq; |
| |
| // The type of the hash table. |
| typedef Unordered_set<Merge_data_key, Merge_data_hash, Merge_data_eq> |
| Merge_data_hashtable; |
| |
| // Given a hash table key, which is just an offset into the section |
| // data, return a pointer to the corresponding constant. |
| const unsigned char* |
| constant(Merge_data_key k) const |
| { |
| gold_assert(k >= 0 && k < this->len_); |
| return this->p_ + k; |
| } |
| |
| // Add a constant to the output. |
| void |
| add_constant(const unsigned char*); |
| |
| // The accumulated data. |
| unsigned char* p_; |
| // The length of the accumulated data. |
| off_t len_; |
| // The size of the allocated buffer. |
| size_t alc_; |
| // The hash table. |
| Merge_data_hashtable hashtable_; |
| }; |
| |
| // Handle SHF_MERGE sections with string data. This is a template |
| // based on the type of the characters in the string. |
| |
| template<typename Char_type> |
| class Output_merge_string : public Output_merge_base |
| { |
| public: |
| Output_merge_string() |
| : Output_merge_base(sizeof(Char_type)), stringpool_(false), hashtable_() |
| { } |
| |
| // Add an input section. |
| bool |
| do_add_input_section(Relobj* object, unsigned int shndx); |
| |
| // Set the final data size. |
| void |
| do_set_address(uint64_t, off_t); |
| |
| // Write the data to the file. |
| void |
| do_write(Output_file*); |
| |
| private: |
| // As we see input sections, we build a mapping from object, section |
| // index and offset to strings. |
| struct Merge_string_key |
| { |
| Relobj* object; |
| unsigned int shndx; |
| off_t offset; |
| |
| Merge_string_key(Relobj *objecta, unsigned int shndxa, off_t offseta) |
| : object(objecta), shndx(shndxa), offset(offseta) |
| { } |
| }; |
| |
| struct Merge_string_key_hash |
| { |
| size_t |
| operator()(const Merge_string_key&) const; |
| }; |
| |
| struct Merge_string_key_eq |
| { |
| bool |
| operator()(const Merge_string_key&, const Merge_string_key&) const; |
| }; |
| |
| typedef Unordered_map<Merge_string_key, const Char_type*, |
| Merge_string_key_hash, Merge_string_key_eq> |
| Merge_string_hashtable; |
| |
| // As we see the strings, we add them to a Stringpool. |
| Stringpool_template<Char_type> stringpool_; |
| // Map from a location in an input object to an entry in the |
| // Stringpool. |
| Merge_string_hashtable hashtable_; |
| }; |
| |
| } // End namespace gold. |
| |
| #endif // !defined(GOLD_MERGE_H) |