diff options
Diffstat (limited to 'gold/ehframe.h')
| -rw-r--r-- | gold/ehframe.h | 359 |
1 files changed, 358 insertions, 1 deletions
diff --git a/gold/ehframe.h b/gold/ehframe.h index 0641ac8..6a584f9 100644 --- a/gold/ehframe.h +++ b/gold/ehframe.h @@ -24,10 +24,16 @@ #define GOLD_EHFRAME_H #include "output.h" +#include "merge.h" namespace gold { +template<int size, bool big_endian> +class Track_relocs; + +class Eh_frame; + // This class manages the .eh_frame_hdr section, which holds the data // for the PT_GNU_EH_FRAME segment. gcc's unwind support code uses // the PT_GNU_EH_FRAME segment to find the list of FDEs. This saves @@ -42,7 +48,20 @@ namespace gold class Eh_frame_hdr : public Output_section_data { public: - Eh_frame_hdr(Output_section* eh_frame_section); + Eh_frame_hdr(Output_section* eh_frame_section, const Eh_frame*); + + // Record that we found an unrecognized .eh_frame section. + void + found_unrecognized_eh_frame_section() + { this->any_unrecognized_eh_frame_sections_ = true; } + + // Record an FDE. + void + record_fde(off_t fde_offset, unsigned char fde_encoding) + { + if (!this->any_unrecognized_eh_frame_sections_) + this->fde_offsets_.push_back(std::make_pair(fde_offset, fde_encoding)); + } // Set the final data size. void @@ -53,8 +72,346 @@ class Eh_frame_hdr : public Output_section_data do_write(Output_file*); private: + // Write the data to the file with the right endianness. + template<int size, bool big_endian> + void + do_sized_write(Output_file*); + + // The data we record for one FDE: the offset of the FDE within the + // .eh_frame section, and the FDE encoding. + typedef std::pair<off_t, unsigned char> Fde_offset; + + // The list of information we record for an FDE. + typedef std::vector<Fde_offset> Fde_offsets; + + // When writing out the header, we convert the FDE offsets into FDE + // addresses. This is a list of pairs of the offset from the header + // to the FDE PC and to the FDE itself. + template<int size> + class Fde_addresses + { + public: + typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; + typedef typename std::pair<Address, Address> Fde_address; + typedef typename std::vector<Fde_address> Fde_address_list; + typedef typename Fde_address_list::iterator iterator; + + Fde_addresses(unsigned int reserve) + : fde_addresses_() + { this->fde_addresses_.reserve(reserve); } + + void + push_back(Address pc_address, Address fde_address) + { + this->fde_addresses_.push_back(std::make_pair(pc_address, fde_address)); + } + + iterator + begin() + { return this->fde_addresses_.begin(); } + + iterator + end() + { return this->fde_addresses_.end(); } + + private: + Fde_address_list fde_addresses_; + }; + + // Compare Fde_address objects. + template<int size> + struct Fde_address_compare + { + bool + operator()(const typename Fde_addresses<size>::Fde_address& f1, + const typename Fde_addresses<size>::Fde_address& f2) const + { return f1.first < f2.first; } + }; + + // Return the PC to which an FDE refers. + template<int size, bool big_endian> + typename elfcpp::Elf_types<size>::Elf_Addr + get_fde_pc(const unsigned char* eh_frame_contents, + off_t fde_offset, unsigned char fde_encoding); + + // Convert Fde_offsets to Fde_addresses. + template<int size, bool big_endian> + void + get_fde_addresses(Output_file* of, + const Fde_offsets* fde_offsets, + Fde_addresses<size>* fde_addresses); + // The .eh_frame section. Output_section* eh_frame_section_; + // The .eh_frame section data. + const Eh_frame* eh_frame_data_; + // Data from the FDEs in the .eh_frame sections. + Fde_offsets fde_offsets_; + // Whether we found any .eh_frame sections which we could not + // process. + bool any_unrecognized_eh_frame_sections_; +}; + +// This class holds an FDE. + +class Fde +{ + public: + Fde(Relobj* object, unsigned int shndx, off_t input_offset, + const unsigned char* contents, size_t length) + : object_(object), shndx_(shndx), input_offset_(input_offset), + contents_(reinterpret_cast<const char*>(contents), length) + { } + + // Return the length of this FDE. Add 4 for the length and 4 for + // the offset to the CIE. + size_t + length() const + { return this->contents_.length() + 8; } + + // Add a mapping for this FDE to MERGE_MAP. + void + add_mapping(off_t output_offset, Merge_map* merge_map) const + { + merge_map->add_mapping(this->object_, this->shndx_, + this->input_offset_, this->length(), + output_offset); + } + + // Write the FDE to OVIEW starting at OFFSET. FDE_ENCODING is the + // encoding, from the CIE. Record the FDE in EH_FRAME_HDR. Return + // the new offset. + template<int size, bool big_endian> + off_t + write(unsigned char* oview, off_t offset, off_t cie_offset, + unsigned char fde_encoding, Eh_frame_hdr* eh_frame_hdr); + + private: + // The object in which this FDE was seen. + Relobj* object_; + // Input section index for this FDE. + unsigned int shndx_; + // Offset within the input section for this FDE. + off_t input_offset_; + // FDE data. + std::string contents_; +}; + +// This class holds a CIE. + +class Cie +{ + public: + Cie(Relobj* object, unsigned int shndx, off_t input_offset, + unsigned char fde_encoding, const char* personality_name, + const unsigned char* contents, size_t length) + : object_(object), + shndx_(shndx), + input_offset_(input_offset), + fde_encoding_(fde_encoding), + personality_name_(personality_name), + fdes_(), + contents_(reinterpret_cast<const char*>(contents), length) + { } + + ~Cie(); + + // We permit copying a CIE when there are no FDEs. This is + // convenient in the code which creates them. + Cie(const Cie& cie) + : object_(cie.object_), + shndx_(cie.shndx_), + input_offset_(cie.input_offset_), + fde_encoding_(cie.fde_encoding_), + personality_name_(cie.personality_name_), + fdes_(), + contents_(cie.contents_) + { gold_assert(cie.fdes_.empty()); } + + // Add an FDE associated with this CIE. + void + add_fde(Fde* fde) + { this->fdes_.push_back(fde); } + + // Return the number of FDEs. + unsigned int + fde_count() const + { return this->fdes_.size(); } + + // Set the output offset of this CIE to OUTPUT_OFFSET. It will be + // followed by all its FDEs. ADDRALIGN is the required address + // alignment, typically 4 or 8. This updates MERGE_MAP with the + // mapping. It returns the new output offset. + off_t + set_output_offset(off_t output_offset, unsigned int addralign, Merge_map*); + + // Write the CIE to OVIEW starting at OFFSET. EH_FRAME_HDR is the + // exception frame header for FDE recording. Return the new offset. + template<int size, bool big_endian> + off_t + write(unsigned char* oview, off_t offset, Eh_frame_hdr* eh_frame_hdr); + + friend bool operator<(const Cie&, const Cie&); + friend bool operator==(const Cie&, const Cie&); + + private: + // The class is not assignable. + Cie& operator=(const Cie&); + + // The object in which this CIE was first seen. + Relobj* object_; + // Input section index for this CIE. + unsigned int shndx_; + // Offset within the input section for this CIE. + off_t input_offset_; + // The encoding of the FDE. This is a DW_EH_PE code. + unsigned char fde_encoding_; + // The name of the personality routine. This will be the name of a + // global symbol, or will be the empty string. + std::string personality_name_; + // List of FDEs. + std::vector<Fde*> fdes_; + // CIE data. + std::string contents_; +}; + +extern bool operator<(const Cie&, const Cie&); +extern bool operator==(const Cie&, const Cie&); + +// This class manages .eh_frame sections. It discards duplicate +// exception information. + +class Eh_frame : public Output_section_data +{ + public: + Eh_frame(); + + // Record the associated Eh_frame_hdr, if any. + void + set_eh_frame_hdr(Eh_frame_hdr* hdr) + { this->eh_frame_hdr_ = hdr; } + + // Add the input section SHNDX in OBJECT. SYMBOLS is the contents + // of the symbol table section (size SYMBOLS_SIZE), SYMBOL_NAMES is + // the symbol names section (size SYMBOL_NAMES_SIZE). RELOC_SHNDX + // is the relocation section if any (0 for none, -1U for multiple). + // RELOC_TYPE is the type of the relocation section if any. This + // returns whether the section was incorporated into the .eh_frame + // data. + template<int size, bool big_endian> + bool + add_ehframe_input_section(Sized_relobj<size, big_endian>* object, + const unsigned char* symbols, + off_t symbols_size, + const unsigned char* symbol_names, + off_t symbol_names_size, + unsigned int shndx, unsigned int reloc_shndx, + unsigned int reloc_type); + + // Return the number of FDEs. + unsigned int + fde_count() const; + + // Set the final data size. + void + do_set_address(uint64_t, off_t); + + // Return the output address for an input address. + bool + do_output_offset(const Relobj*, unsigned int shndx, off_t offset, + off_t* poutput) const; + + // Write the data to the file. + void + do_write(Output_file*); + + private: + // The comparison routine for the CIE map. + struct Cie_less + { + bool + operator()(const Cie* cie1, const Cie* cie2) const + { return *cie1 < *cie2; } + }; + + // A mapping from unique CIEs to their offset in the output file. + typedef std::map<Cie*, uint64_t, Cie_less> Cie_offsets; + + // A list of unmergeable CIEs with their offsets. + typedef std::vector<std::pair<Cie*, uint64_t> > Unmergeable_cie_offsets; + + // A mapping from offsets to CIEs. This is used while reading an + // input section. + typedef std::map<uint64_t, Cie*> Offsets_to_cie; + + // A list of CIEs, and a bool indicating whether the CIE is + // mergeable. + typedef std::vector<std::pair<Cie*, bool> > New_cies; + + // Skip an LEB128. + static bool + skip_leb128(const unsigned char**, const unsigned char*); + + // The implementation of add_ehframe_input_section. + template<int size, bool big_endian> + bool + do_add_ehframe_input_section(Sized_relobj<size, big_endian>* object, + const unsigned char* symbols, + off_t symbols_size, + const unsigned char* symbol_names, + off_t symbol_names_size, + unsigned int shndx, + unsigned int reloc_shndx, + unsigned int reloc_type, + const unsigned char* pcontents, + off_t contents_len, + New_cies*); + + // Read a CIE. + template<int size, bool big_endian> + bool + read_cie(Sized_relobj<size, big_endian>* object, + unsigned int shndx, + const unsigned char* symbols, + off_t symbols_size, + const unsigned char* symbol_names, + off_t symbol_names_size, + const unsigned char* pcontents, + const unsigned char* pcie, + const unsigned char *pcieend, + Track_relocs<size, big_endian>* relocs, + Offsets_to_cie* cies, + New_cies* new_cies); + + // Read an FDE. + template<int size, bool big_endian> + bool + read_fde(Sized_relobj<size, big_endian>* object, + unsigned int shndx, + const unsigned char* symbols, + off_t symbols_size, + const unsigned char* pcontents, + unsigned int offset, + const unsigned char* pfde, + const unsigned char *pfdeend, + Track_relocs<size, big_endian>* relocs, + Offsets_to_cie* cies); + + // Template version of write function. + template<int size, bool big_endian> + void + do_sized_write(unsigned char* oview); + + // The exception frame header, if any. + Eh_frame_hdr* eh_frame_hdr_; + // A mapping from all unique CIEs to their offset in the output + // file. + Cie_offsets cie_offsets_; + // A mapping from unmergeable CIEs to their offset in the output + // file. + Unmergeable_cie_offsets unmergeable_cie_offsets_; + // A mapping from input sections to the output section. + Merge_map merge_map_; }; } // End namespace gold. |