| // target.h -- target support for gold -*- C++ -*- |
| |
| // Copyright (C) 2006-2021 Free Software Foundation, Inc. |
| // Written by Ian Lance Taylor <iant@google.com>. |
| |
| // This file is part of gold. |
| |
| // This program is free software; you can redistribute it and/or modify |
| // it under the terms of the GNU General Public License as published by |
| // the Free Software Foundation; either version 3 of the License, or |
| // (at your option) any later version. |
| |
| // This program is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License |
| // along with this program; if not, write to the Free Software |
| // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| // MA 02110-1301, USA. |
| |
| // The abstract class Target is the interface for target specific |
| // support. It defines abstract methods which each target must |
| // implement. Typically there will be one target per processor, but |
| // in some cases it may be necessary to have subclasses. |
| |
| // For speed and consistency we want to use inline functions to handle |
| // relocation processing. So besides implementations of the abstract |
| // methods, each target is expected to define a template |
| // specialization of the relocation functions. |
| |
| #ifndef GOLD_TARGET_H |
| #define GOLD_TARGET_H |
| |
| #include "elfcpp.h" |
| #include "options.h" |
| #include "parameters.h" |
| #include "stringpool.h" |
| #include "debug.h" |
| |
| namespace gold |
| { |
| |
| class Object; |
| class Relobj; |
| template<int size, bool big_endian> |
| class Sized_relobj; |
| template<int size, bool big_endian> |
| class Sized_relobj_file; |
| class Relocatable_relocs; |
| template<int size, bool big_endian> |
| struct Relocate_info; |
| class Reloc_symbol_changes; |
| class Symbol; |
| template<int size> |
| class Sized_symbol; |
| class Symbol_table; |
| class Output_data; |
| class Output_data_got_base; |
| class Output_section; |
| class Input_objects; |
| class Task; |
| struct Symbol_location; |
| class Versions; |
| |
| // The abstract class for target specific handling. |
| |
| class Target |
| { |
| public: |
| virtual ~Target() |
| { } |
| |
| // Return the bit size that this target implements. This should |
| // return 32 or 64. |
| int |
| get_size() const |
| { return this->pti_->size; } |
| |
| // Return whether this target is big-endian. |
| bool |
| is_big_endian() const |
| { return this->pti_->is_big_endian; } |
| |
| // Machine code to store in e_machine field of ELF header. |
| elfcpp::EM |
| machine_code() const |
| { return this->pti_->machine_code; } |
| |
| // Processor specific flags to store in e_flags field of ELF header. |
| elfcpp::Elf_Word |
| processor_specific_flags() const |
| { return this->processor_specific_flags_; } |
| |
| // Whether processor specific flags are set at least once. |
| bool |
| are_processor_specific_flags_set() const |
| { return this->are_processor_specific_flags_set_; } |
| |
| // Whether this target has a specific make_symbol function. |
| bool |
| has_make_symbol() const |
| { return this->pti_->has_make_symbol; } |
| |
| // Whether this target has a specific resolve function. |
| bool |
| has_resolve() const |
| { return this->pti_->has_resolve; } |
| |
| // Whether this target has a specific code fill function. |
| bool |
| has_code_fill() const |
| { return this->pti_->has_code_fill; } |
| |
| // Return the default name of the dynamic linker. |
| const char* |
| dynamic_linker() const |
| { return this->pti_->dynamic_linker; } |
| |
| // Return the default address to use for the text segment. |
| // If a -z max-page-size argument has set the ABI page size |
| // to a value larger than the default starting address, |
| // bump the starting address up to the page size, to avoid |
| // misaligning the text segment in the file. |
| uint64_t |
| default_text_segment_address() const |
| { |
| uint64_t addr = this->pti_->default_text_segment_address; |
| uint64_t pagesize = this->abi_pagesize(); |
| if (addr < pagesize) |
| addr = pagesize; |
| return addr; |
| } |
| |
| // Return the ABI specified page size. |
| uint64_t |
| abi_pagesize() const |
| { |
| if (parameters->options().max_page_size() > 0) |
| return parameters->options().max_page_size(); |
| else |
| return this->pti_->abi_pagesize; |
| } |
| |
| // Return the common page size used on actual systems. |
| uint64_t |
| common_pagesize() const |
| { |
| if (parameters->options().common_page_size() > 0) |
| return std::min(parameters->options().common_page_size(), |
| this->abi_pagesize()); |
| else |
| return std::min(this->pti_->common_pagesize, |
| this->abi_pagesize()); |
| } |
| |
| // Return whether PF_X segments must contain nothing but the contents of |
| // SHF_EXECINSTR sections (no non-executable data, no headers). |
| bool |
| isolate_execinstr() const |
| { return this->pti_->isolate_execinstr; } |
| |
| uint64_t |
| rosegment_gap() const |
| { return this->pti_->rosegment_gap; } |
| |
| // If we see some object files with .note.GNU-stack sections, and |
| // some objects files without them, this returns whether we should |
| // consider the object files without them to imply that the stack |
| // should be executable. |
| bool |
| is_default_stack_executable() const |
| { return this->pti_->is_default_stack_executable; } |
| |
| // Return a character which may appear as a prefix for a wrap |
| // symbol. If this character appears, we strip it when checking for |
| // wrapping and add it back when forming the final symbol name. |
| // This should be '\0' if not special prefix is required, which is |
| // the normal case. |
| char |
| wrap_char() const |
| { return this->pti_->wrap_char; } |
| |
| // Return the special section index which indicates a small common |
| // symbol. This will return SHN_UNDEF if there are no small common |
| // symbols. |
| elfcpp::Elf_Half |
| small_common_shndx() const |
| { return this->pti_->small_common_shndx; } |
| |
| // Return values to add to the section flags for the section holding |
| // small common symbols. |
| elfcpp::Elf_Xword |
| small_common_section_flags() const |
| { |
| gold_assert(this->pti_->small_common_shndx != elfcpp::SHN_UNDEF); |
| return this->pti_->small_common_section_flags; |
| } |
| |
| // Return the special section index which indicates a large common |
| // symbol. This will return SHN_UNDEF if there are no large common |
| // symbols. |
| elfcpp::Elf_Half |
| large_common_shndx() const |
| { return this->pti_->large_common_shndx; } |
| |
| // Return values to add to the section flags for the section holding |
| // large common symbols. |
| elfcpp::Elf_Xword |
| large_common_section_flags() const |
| { |
| gold_assert(this->pti_->large_common_shndx != elfcpp::SHN_UNDEF); |
| return this->pti_->large_common_section_flags; |
| } |
| |
| // This hook is called when an output section is created. |
| void |
| new_output_section(Output_section* os) const |
| { this->do_new_output_section(os); } |
| |
| // This is called to tell the target to complete any sections it is |
| // handling. After this all sections must have their final size. |
| void |
| finalize_sections(Layout* layout, const Input_objects* input_objects, |
| Symbol_table* symtab) |
| { return this->do_finalize_sections(layout, input_objects, symtab); } |
| |
| // Return the value to use for a global symbol which needs a special |
| // value in the dynamic symbol table. This will only be called if |
| // the backend first calls symbol->set_needs_dynsym_value(). |
| uint64_t |
| dynsym_value(const Symbol* sym) const |
| { return this->do_dynsym_value(sym); } |
| |
| // Return a string to use to fill out a code section. This is |
| // basically one or more NOPS which must fill out the specified |
| // length in bytes. |
| std::string |
| code_fill(section_size_type length) const |
| { return this->do_code_fill(length); } |
| |
| // Return whether SYM is known to be defined by the ABI. This is |
| // used to avoid inappropriate warnings about undefined symbols. |
| bool |
| is_defined_by_abi(const Symbol* sym) const |
| { return this->do_is_defined_by_abi(sym); } |
| |
| // Adjust the output file header before it is written out. VIEW |
| // points to the header in external form. LEN is the length. |
| void |
| adjust_elf_header(unsigned char* view, int len) |
| { return this->do_adjust_elf_header(view, len); } |
| |
| // Return address and size to plug into eh_frame FDEs associated with a PLT. |
| void |
| plt_fde_location(const Output_data* plt, unsigned char* oview, |
| uint64_t* address, off_t* len) const |
| { return this->do_plt_fde_location(plt, oview, address, len); } |
| |
| // Return whether NAME is a local label name. This is used to implement the |
| // --discard-locals options. |
| bool |
| is_local_label_name(const char* name) const |
| { return this->do_is_local_label_name(name); } |
| |
| // Get the symbol index to use for a target specific reloc. |
| unsigned int |
| reloc_symbol_index(void* arg, unsigned int type) const |
| { return this->do_reloc_symbol_index(arg, type); } |
| |
| // Get the addend to use for a target specific reloc. |
| uint64_t |
| reloc_addend(void* arg, unsigned int type, uint64_t addend) const |
| { return this->do_reloc_addend(arg, type, addend); } |
| |
| // Return the PLT address to use for a global symbol. |
| uint64_t |
| plt_address_for_global(const Symbol* sym) const |
| { return this->do_plt_address_for_global(sym); } |
| |
| // Return the PLT address to use for a local symbol. |
| uint64_t |
| plt_address_for_local(const Relobj* object, unsigned int symndx) const |
| { return this->do_plt_address_for_local(object, symndx); } |
| |
| // Return the offset to use for the GOT_INDX'th got entry which is |
| // for a local tls symbol specified by OBJECT, SYMNDX. |
| int64_t |
| tls_offset_for_local(const Relobj* object, |
| unsigned int symndx, |
| Output_data_got_base* got, |
| unsigned int got_indx, |
| uint64_t addend) const |
| { return do_tls_offset_for_local(object, symndx, got, got_indx, addend); } |
| |
| // Return the offset to use for the GOT_INDX'th got entry which is |
| // for global tls symbol GSYM. |
| int64_t |
| tls_offset_for_global(Symbol* gsym, |
| Output_data_got_base* got, |
| unsigned int got_indx, |
| uint64_t addend) const |
| { return do_tls_offset_for_global(gsym, got, got_indx, addend); } |
| |
| // For targets that use function descriptors, if LOC is the location |
| // of a function, modify it to point at the function entry location. |
| void |
| function_location(Symbol_location* loc) const |
| { return do_function_location(loc); } |
| |
| // Return whether this target can use relocation types to determine |
| // if a function's address is taken. |
| bool |
| can_check_for_function_pointers() const |
| { return this->do_can_check_for_function_pointers(); } |
| |
| // Return whether a relocation to a merged section can be processed |
| // to retrieve the contents. |
| bool |
| can_icf_inline_merge_sections () const |
| { return this->pti_->can_icf_inline_merge_sections; } |
| |
| // Whether a section called SECTION_NAME may have function pointers to |
| // sections not eligible for safe ICF folding. |
| virtual bool |
| section_may_have_icf_unsafe_pointers(const char* section_name) const |
| { return this->do_section_may_have_icf_unsafe_pointers(section_name); } |
| |
| // Return the base to use for the PC value in an FDE when it is |
| // encoded using DW_EH_PE_datarel. This does not appear to be |
| // documented anywhere, but it is target specific. Any use of |
| // DW_EH_PE_datarel in gcc requires defining a special macro |
| // (ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX) to output the value. |
| uint64_t |
| ehframe_datarel_base() const |
| { return this->do_ehframe_datarel_base(); } |
| |
| // Return true if a reference to SYM from a reloc at *PRELOC |
| // means that the current function may call an object compiled |
| // without -fsplit-stack. SYM is known to be defined in an object |
| // compiled without -fsplit-stack. |
| bool |
| is_call_to_non_split(const Symbol* sym, const unsigned char* preloc, |
| const unsigned char* view, |
| section_size_type view_size) const |
| { return this->do_is_call_to_non_split(sym, preloc, view, view_size); } |
| |
| // A function starts at OFFSET in section SHNDX in OBJECT. That |
| // function was compiled with -fsplit-stack, but it refers to a |
| // function which was compiled without -fsplit-stack. VIEW is a |
| // modifiable view of the section; VIEW_SIZE is the size of the |
| // view. The target has to adjust the function so that it allocates |
| // enough stack. |
| void |
| calls_non_split(Relobj* object, unsigned int shndx, |
| section_offset_type fnoffset, section_size_type fnsize, |
| const unsigned char* prelocs, size_t reloc_count, |
| unsigned char* view, section_size_type view_size, |
| std::string* from, std::string* to) const |
| { |
| this->do_calls_non_split(object, shndx, fnoffset, fnsize, |
| prelocs, reloc_count, view, view_size, |
| from, to); |
| } |
| |
| // Make an ELF object. |
| template<int size, bool big_endian> |
| Object* |
| make_elf_object(const std::string& name, Input_file* input_file, |
| off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr) |
| { return this->do_make_elf_object(name, input_file, offset, ehdr); } |
| |
| // Make an output section. |
| Output_section* |
| make_output_section(const char* name, elfcpp::Elf_Word type, |
| elfcpp::Elf_Xword flags) |
| { return this->do_make_output_section(name, type, flags); } |
| |
| // Return true if target wants to perform relaxation. |
| bool |
| may_relax() const |
| { |
| // Run the dummy relaxation pass twice if relaxation debugging is enabled. |
| if (is_debugging_enabled(DEBUG_RELAXATION)) |
| return true; |
| |
| return this->do_may_relax(); |
| } |
| |
| // Perform a relaxation pass. Return true if layout may be changed. |
| bool |
| relax(int pass, const Input_objects* input_objects, Symbol_table* symtab, |
| Layout* layout, const Task* task) |
| { |
| // Run the dummy relaxation pass twice if relaxation debugging is enabled. |
| if (is_debugging_enabled(DEBUG_RELAXATION)) |
| return pass < 2; |
| |
| return this->do_relax(pass, input_objects, symtab, layout, task); |
| } |
| |
| // Return the target-specific name of attributes section. This is |
| // NULL if a target does not use attributes section or if it uses |
| // the default section name ".gnu.attributes". |
| const char* |
| attributes_section() const |
| { return this->pti_->attributes_section; } |
| |
| // Return the vendor name of vendor attributes. |
| const char* |
| attributes_vendor() const |
| { return this->pti_->attributes_vendor; } |
| |
| // Whether a section called NAME is an attribute section. |
| bool |
| is_attributes_section(const char* name) const |
| { |
| return ((this->pti_->attributes_section != NULL |
| && strcmp(name, this->pti_->attributes_section) == 0) |
| || strcmp(name, ".gnu.attributes") == 0); |
| } |
| |
| // Return a bit mask of argument types for attribute with TAG. |
| int |
| attribute_arg_type(int tag) const |
| { return this->do_attribute_arg_type(tag); } |
| |
| // Return the attribute tag of the position NUM in the list of fixed |
| // attributes. Normally there is no reordering and |
| // attributes_order(NUM) == NUM. |
| int |
| attributes_order(int num) const |
| { return this->do_attributes_order(num); } |
| |
| // When a target is selected as the default target, we call this method, |
| // which may be used for expensive, target-specific initialization. |
| void |
| select_as_default_target() |
| { this->do_select_as_default_target(); } |
| |
| // Return the value to store in the EI_OSABI field in the ELF |
| // header. |
| elfcpp::ELFOSABI |
| osabi() const |
| { return this->osabi_; } |
| |
| // Set the value to store in the EI_OSABI field in the ELF header. |
| void |
| set_osabi(elfcpp::ELFOSABI osabi) |
| { this->osabi_ = osabi; } |
| |
| // Define target-specific standard symbols. |
| void |
| define_standard_symbols(Symbol_table* symtab, Layout* layout) |
| { this->do_define_standard_symbols(symtab, layout); } |
| |
| // Return the output section name to use given an input section |
| // name, or NULL if no target specific name mapping is required. |
| // Set *PLEN to the length of the name if returning non-NULL. |
| const char* |
| output_section_name(const Relobj* relobj, |
| const char* name, |
| size_t* plen) const |
| { return this->do_output_section_name(relobj, name, plen); } |
| |
| // Add any special sections for this symbol to the gc work list. |
| void |
| gc_mark_symbol(Symbol_table* symtab, Symbol* sym) const |
| { this->do_gc_mark_symbol(symtab, sym); } |
| |
| // Return the name of the entry point symbol. |
| const char* |
| entry_symbol_name() const |
| { return this->pti_->entry_symbol_name; } |
| |
| // Return the size in bits of SHT_HASH entry. |
| int |
| hash_entry_size() const |
| { return this->pti_->hash_entry_size; } |
| |
| // Return the section type to use for unwind sections. |
| unsigned int |
| unwind_section_type() const |
| { return this->pti_->unwind_section_type; } |
| |
| // Whether the target has a custom set_dynsym_indexes method. |
| bool |
| has_custom_set_dynsym_indexes() const |
| { return this->do_has_custom_set_dynsym_indexes(); } |
| |
| // Custom set_dynsym_indexes method for a target. |
| unsigned int |
| set_dynsym_indexes(std::vector<Symbol*>* dyn_symbols, unsigned int index, |
| std::vector<Symbol*>* syms, Stringpool* dynpool, |
| Versions* versions, Symbol_table* symtab) const |
| { |
| return this->do_set_dynsym_indexes(dyn_symbols, index, syms, dynpool, |
| versions, symtab); |
| } |
| |
| // Get the custom dynamic tag value. |
| unsigned int |
| dynamic_tag_custom_value(elfcpp::DT tag) const |
| { return this->do_dynamic_tag_custom_value(tag); } |
| |
| // Adjust the value written to the dynamic symbol table. |
| void |
| adjust_dyn_symbol(const Symbol* sym, unsigned char* view) const |
| { this->do_adjust_dyn_symbol(sym, view); } |
| |
| // Return whether to include the section in the link. |
| bool |
| should_include_section(elfcpp::Elf_Word sh_type) const |
| { return this->do_should_include_section(sh_type); } |
| |
| // Finalize the target-specific properties in the .note.gnu.property section. |
| void |
| finalize_gnu_properties(Layout* layout) const |
| { this->do_finalize_gnu_properties(layout); } |
| |
| protected: |
| // This struct holds the constant information for a child class. We |
| // use a struct to avoid the overhead of virtual function calls for |
| // simple information. |
| struct Target_info |
| { |
| // Address size (32 or 64). |
| int size; |
| // Whether the target is big endian. |
| bool is_big_endian; |
| // The code to store in the e_machine field of the ELF header. |
| elfcpp::EM machine_code; |
| // Whether this target has a specific make_symbol function. |
| bool has_make_symbol; |
| // Whether this target has a specific resolve function. |
| bool has_resolve; |
| // Whether this target has a specific code fill function. |
| bool has_code_fill; |
| // Whether an object file with no .note.GNU-stack sections implies |
| // that the stack should be executable. |
| bool is_default_stack_executable; |
| // Whether a relocation to a merged section can be processed to |
| // retrieve the contents. |
| bool can_icf_inline_merge_sections; |
| // Prefix character to strip when checking for wrapping. |
| char wrap_char; |
| // The default dynamic linker name. |
| const char* dynamic_linker; |
| // The default text segment address. |
| uint64_t default_text_segment_address; |
| // The ABI specified page size. |
| uint64_t abi_pagesize; |
| // The common page size used by actual implementations. |
| uint64_t common_pagesize; |
| // Whether PF_X segments must contain nothing but the contents of |
| // SHF_EXECINSTR sections (no non-executable data, no headers). |
| bool isolate_execinstr; |
| // If nonzero, distance from the text segment to the read-only segment. |
| uint64_t rosegment_gap; |
| // The special section index for small common symbols; SHN_UNDEF |
| // if none. |
| elfcpp::Elf_Half small_common_shndx; |
| // The special section index for large common symbols; SHN_UNDEF |
| // if none. |
| elfcpp::Elf_Half large_common_shndx; |
| // Section flags for small common section. |
| elfcpp::Elf_Xword small_common_section_flags; |
| // Section flags for large common section. |
| elfcpp::Elf_Xword large_common_section_flags; |
| // Name of attributes section if it is not ".gnu.attributes". |
| const char* attributes_section; |
| // Vendor name of vendor attributes. |
| const char* attributes_vendor; |
| // Name of the main entry point to the program. |
| const char* entry_symbol_name; |
| // Size (in bits) of SHT_HASH entry. Always equal to 32, except for |
| // 64-bit S/390. |
| const int hash_entry_size; |
| // Processor-specific section type for ".eh_frame" (unwind) sections. |
| // SHT_PROGBITS if there is no special section type. |
| const unsigned int unwind_section_type; |
| }; |
| |
| Target(const Target_info* pti) |
| : pti_(pti), processor_specific_flags_(0), |
| are_processor_specific_flags_set_(false), osabi_(elfcpp::ELFOSABI_NONE) |
| { } |
| |
| // Virtual function which may be implemented by the child class. |
| virtual void |
| do_new_output_section(Output_section*) const |
| { } |
| |
| // Virtual function which may be implemented by the child class. |
| virtual void |
| do_finalize_sections(Layout*, const Input_objects*, Symbol_table*) |
| { } |
| |
| // Virtual function which may be implemented by the child class. |
| virtual uint64_t |
| do_dynsym_value(const Symbol*) const |
| { gold_unreachable(); } |
| |
| // Virtual function which must be implemented by the child class if |
| // needed. |
| virtual std::string |
| do_code_fill(section_size_type) const |
| { gold_unreachable(); } |
| |
| // Virtual function which may be implemented by the child class. |
| virtual bool |
| do_is_defined_by_abi(const Symbol*) const |
| { return false; } |
| |
| // Adjust the output file header before it is written out. VIEW |
| // points to the header in external form. LEN is the length, and |
| // will be one of the values of elfcpp::Elf_sizes<size>::ehdr_size. |
| // By default, we set the EI_OSABI field if requested (in |
| // Sized_target). |
| virtual void |
| do_adjust_elf_header(unsigned char*, int) = 0; |
| |
| // Return address and size to plug into eh_frame FDEs associated with a PLT. |
| virtual void |
| do_plt_fde_location(const Output_data* plt, unsigned char* oview, |
| uint64_t* address, off_t* len) const; |
| |
| // Virtual function which may be overridden by the child class. |
| virtual bool |
| do_is_local_label_name(const char*) const; |
| |
| // Virtual function that must be overridden by a target which uses |
| // target specific relocations. |
| virtual unsigned int |
| do_reloc_symbol_index(void*, unsigned int) const |
| { gold_unreachable(); } |
| |
| // Virtual function that must be overridden by a target which uses |
| // target specific relocations. |
| virtual uint64_t |
| do_reloc_addend(void*, unsigned int, uint64_t) const |
| { gold_unreachable(); } |
| |
| // Virtual functions that must be overridden by a target that uses |
| // STT_GNU_IFUNC symbols. |
| virtual uint64_t |
| do_plt_address_for_global(const Symbol*) const |
| { gold_unreachable(); } |
| |
| virtual uint64_t |
| do_plt_address_for_local(const Relobj*, unsigned int) const |
| { gold_unreachable(); } |
| |
| virtual int64_t |
| do_tls_offset_for_local(const Relobj*, unsigned int, |
| Output_data_got_base*, unsigned int, |
| uint64_t) const |
| { gold_unreachable(); } |
| |
| virtual int64_t |
| do_tls_offset_for_global(Symbol*, Output_data_got_base*, unsigned int, |
| uint64_t) const |
| { gold_unreachable(); } |
| |
| virtual void |
| do_function_location(Symbol_location*) const = 0; |
| |
| // Virtual function which may be overriden by the child class. |
| virtual bool |
| do_can_check_for_function_pointers() const |
| { return false; } |
| |
| // Virtual function which may be overridden by the child class. We |
| // recognize some default sections for which we don't care whether |
| // they have function pointers. |
| virtual bool |
| do_section_may_have_icf_unsafe_pointers(const char* section_name) const |
| { |
| // We recognize sections for normal vtables, construction vtables and |
| // EH frames. |
| return (!is_prefix_of(".rodata._ZTV", section_name) |
| && !is_prefix_of(".data.rel.ro._ZTV", section_name) |
| && !is_prefix_of(".rodata._ZTC", section_name) |
| && !is_prefix_of(".data.rel.ro._ZTC", section_name) |
| && !is_prefix_of(".eh_frame", section_name)); |
| } |
| |
| virtual uint64_t |
| do_ehframe_datarel_base() const |
| { gold_unreachable(); } |
| |
| // Virtual function which may be overridden by the child class. The |
| // default implementation is that any function not defined by the |
| // ABI is a call to a non-split function. |
| virtual bool |
| do_is_call_to_non_split(const Symbol* sym, const unsigned char*, |
| const unsigned char*, section_size_type) const; |
| |
| // Virtual function which may be overridden by the child class. |
| virtual void |
| do_calls_non_split(Relobj* object, unsigned int, section_offset_type, |
| section_size_type, const unsigned char*, size_t, |
| unsigned char*, section_size_type, |
| std::string*, std::string*) const; |
| |
| // make_elf_object hooks. There are four versions of these for |
| // different address sizes and endianness. |
| |
| // Set processor specific flags. |
| void |
| set_processor_specific_flags(elfcpp::Elf_Word flags) |
| { |
| this->processor_specific_flags_ = flags; |
| this->are_processor_specific_flags_set_ = true; |
| } |
| |
| #ifdef HAVE_TARGET_32_LITTLE |
| // Virtual functions which may be overridden by the child class. |
| virtual Object* |
| do_make_elf_object(const std::string&, Input_file*, off_t, |
| const elfcpp::Ehdr<32, false>&); |
| #endif |
| |
| #ifdef HAVE_TARGET_32_BIG |
| // Virtual functions which may be overridden by the child class. |
| virtual Object* |
| do_make_elf_object(const std::string&, Input_file*, off_t, |
| const elfcpp::Ehdr<32, true>&); |
| #endif |
| |
| #ifdef HAVE_TARGET_64_LITTLE |
| // Virtual functions which may be overridden by the child class. |
| virtual Object* |
| do_make_elf_object(const std::string&, Input_file*, off_t, |
| const elfcpp::Ehdr<64, false>& ehdr); |
| #endif |
| |
| #ifdef HAVE_TARGET_64_BIG |
| // Virtual functions which may be overridden by the child class. |
| virtual Object* |
| do_make_elf_object(const std::string& name, Input_file* input_file, |
| off_t offset, const elfcpp::Ehdr<64, true>& ehdr); |
| #endif |
| |
| // Virtual functions which may be overridden by the child class. |
| virtual Output_section* |
| do_make_output_section(const char* name, elfcpp::Elf_Word type, |
| elfcpp::Elf_Xword flags); |
| |
| // Virtual function which may be overridden by the child class. |
| virtual bool |
| do_may_relax() const |
| { return parameters->options().relax(); } |
| |
| // Virtual function which may be overridden by the child class. |
| virtual bool |
| do_relax(int, const Input_objects*, Symbol_table*, Layout*, const Task*) |
| { return false; } |
| |
| // A function for targets to call. Return whether BYTES/LEN matches |
| // VIEW/VIEW_SIZE at OFFSET. |
| bool |
| match_view(const unsigned char* view, section_size_type view_size, |
| section_offset_type offset, const char* bytes, size_t len) const; |
| |
| // Set the contents of a VIEW/VIEW_SIZE to nops starting at OFFSET |
| // for LEN bytes. |
| void |
| set_view_to_nop(unsigned char* view, section_size_type view_size, |
| section_offset_type offset, size_t len) const; |
| |
| // This must be overridden by the child class if it has target-specific |
| // attributes subsection in the attribute section. |
| virtual int |
| do_attribute_arg_type(int) const |
| { gold_unreachable(); } |
| |
| // This may be overridden by the child class. |
| virtual int |
| do_attributes_order(int num) const |
| { return num; } |
| |
| // This may be overridden by the child class. |
| virtual void |
| do_select_as_default_target() |
| { } |
| |
| // This may be overridden by the child class. |
| virtual void |
| do_define_standard_symbols(Symbol_table*, Layout*) |
| { } |
| |
| // This may be overridden by the child class. |
| virtual const char* |
| do_output_section_name(const Relobj*, const char*, size_t*) const |
| { return NULL; } |
| |
| // This may be overridden by the child class. |
| virtual void |
| do_gc_mark_symbol(Symbol_table*, Symbol*) const |
| { } |
| |
| // This may be overridden by the child class. |
| virtual bool |
| do_has_custom_set_dynsym_indexes() const |
| { return false; } |
| |
| // This may be overridden by the child class. |
| virtual unsigned int |
| do_set_dynsym_indexes(std::vector<Symbol*>*, unsigned int, |
| std::vector<Symbol*>*, Stringpool*, Versions*, |
| Symbol_table*) const |
| { gold_unreachable(); } |
| |
| // This may be overridden by the child class. |
| virtual unsigned int |
| do_dynamic_tag_custom_value(elfcpp::DT) const |
| { gold_unreachable(); } |
| |
| // This may be overridden by the child class. |
| virtual void |
| do_adjust_dyn_symbol(const Symbol*, unsigned char*) const |
| { } |
| |
| // This may be overridden by the child class. |
| virtual bool |
| do_should_include_section(elfcpp::Elf_Word) const |
| { return true; } |
| |
| // Finalize the target-specific properties in the .note.gnu.property section. |
| virtual void |
| do_finalize_gnu_properties(Layout*) const |
| { } |
| |
| private: |
| // The implementations of the four do_make_elf_object virtual functions are |
| // almost identical except for their sizes and endianness. We use a template. |
| // for their implementations. |
| template<int size, bool big_endian> |
| inline Object* |
| do_make_elf_object_implementation(const std::string&, Input_file*, off_t, |
| const elfcpp::Ehdr<size, big_endian>&); |
| |
| Target(const Target&); |
| Target& operator=(const Target&); |
| |
| // The target information. |
| const Target_info* pti_; |
| // Processor-specific flags. |
| elfcpp::Elf_Word processor_specific_flags_; |
| // Whether the processor-specific flags are set at least once. |
| bool are_processor_specific_flags_set_; |
| // If not ELFOSABI_NONE, the value to put in the EI_OSABI field of |
| // the ELF header. This is handled at this level because it is |
| // OS-specific rather than processor-specific. |
| elfcpp::ELFOSABI osabi_; |
| }; |
| |
| // The abstract class for a specific size and endianness of target. |
| // Each actual target implementation class should derive from an |
| // instantiation of Sized_target. |
| |
| template<int size, bool big_endian> |
| class Sized_target : public Target |
| { |
| public: |
| // Make a new symbol table entry for the target. This should be |
| // overridden by a target which needs additional information in the |
| // symbol table. This will only be called if has_make_symbol() |
| // returns true. |
| virtual Sized_symbol<size>* |
| make_symbol(const char*, elfcpp::STT, Object*, unsigned int, uint64_t) |
| { gold_unreachable(); } |
| |
| // Resolve a symbol for the target. This should be overridden by a |
| // target which needs to take special action. TO is the |
| // pre-existing symbol. SYM is the new symbol, seen in OBJECT. |
| // VERSION is the version of SYM. This will only be called if |
| // has_resolve() returns true. |
| virtual bool |
| resolve(Symbol*, const elfcpp::Sym<size, big_endian>&, Object*, |
| const char*) |
| { gold_unreachable(); } |
| |
| // Process the relocs for a section, and record information of the |
| // mapping from source to destination sections. This mapping is later |
| // used to determine unreferenced garbage sections. This procedure is |
| // only called during garbage collection. |
| virtual void |
| gc_process_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<size, big_endian>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols) = 0; |
| |
| // Scan the relocs for a section, and record any information |
| // required for the symbol. SYMTAB is the symbol table. OBJECT is |
| // the object in which the section appears. DATA_SHNDX is the |
| // section index that these relocs apply to. SH_TYPE is the type of |
| // the relocation section, SHT_REL or SHT_RELA. PRELOCS points to |
| // the relocation data. RELOC_COUNT is the number of relocs. |
| // LOCAL_SYMBOL_COUNT is the number of local symbols. |
| // OUTPUT_SECTION is the output section. |
| // NEEDS_SPECIAL_OFFSET_HANDLING is true if offsets to the output |
| // sections are not mapped as usual. PLOCAL_SYMBOLS points to the |
| // local symbol data from OBJECT. GLOBAL_SYMBOLS is the array of |
| // pointers to the global symbol table from OBJECT. |
| virtual void |
| scan_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<size, big_endian>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols) = 0; |
| |
| // Relocate section data. SH_TYPE is the type of the relocation |
| // section, SHT_REL or SHT_RELA. PRELOCS points to the relocation |
| // information. RELOC_COUNT is the number of relocs. |
| // OUTPUT_SECTION is the output section. |
| // NEEDS_SPECIAL_OFFSET_HANDLING is true if offsets must be mapped |
| // to correspond to the output section. VIEW is a view into the |
| // output file holding the section contents, VIEW_ADDRESS is the |
| // virtual address of the view, and VIEW_SIZE is the size of the |
| // view. If NEEDS_SPECIAL_OFFSET_HANDLING is true, the VIEW_xx |
| // parameters refer to the complete output section data, not just |
| // the input section data. |
| virtual void |
| relocate_section(const Relocate_info<size, big_endian>*, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| unsigned char* view, |
| typename elfcpp::Elf_types<size>::Elf_Addr view_address, |
| section_size_type view_size, |
| const Reloc_symbol_changes*) = 0; |
| |
| // Scan the relocs during a relocatable link. The parameters are |
| // like scan_relocs, with an additional Relocatable_relocs |
| // parameter, used to record the disposition of the relocs. |
| virtual void |
| scan_relocatable_relocs(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<size, big_endian>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols, |
| Relocatable_relocs*) = 0; |
| |
| // Scan the relocs for --emit-relocs. The parameters are |
| // like scan_relocatable_relocs. |
| virtual void |
| emit_relocs_scan(Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj_file<size, big_endian>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_syms, |
| Relocatable_relocs* rr) = 0; |
| |
| // Emit relocations for a section during a relocatable link, and for |
| // --emit-relocs. The parameters are like relocate_section, with |
| // additional parameters for the view of the output reloc section. |
| virtual void |
| relocate_relocs(const Relocate_info<size, big_endian>*, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| typename elfcpp::Elf_types<size>::Elf_Off |
| offset_in_output_section, |
| unsigned char* view, |
| typename elfcpp::Elf_types<size>::Elf_Addr view_address, |
| section_size_type view_size, |
| unsigned char* reloc_view, |
| section_size_type reloc_view_size) = 0; |
| |
| // Perform target-specific processing in a relocatable link. This is |
| // only used if we use the relocation strategy RELOC_SPECIAL. |
| // RELINFO points to a Relocation_info structure. SH_TYPE is the relocation |
| // section type. PRELOC_IN points to the original relocation. RELNUM is |
| // the index number of the relocation in the relocation section. |
| // OUTPUT_SECTION is the output section to which the relocation is applied. |
| // OFFSET_IN_OUTPUT_SECTION is the offset of the relocation input section |
| // within the output section. VIEW points to the output view of the |
| // output section. VIEW_ADDRESS is output address of the view. VIEW_SIZE |
| // is the size of the output view and PRELOC_OUT points to the new |
| // relocation in the output object. |
| // |
| // A target only needs to override this if the generic code in |
| // target-reloc.h cannot handle some relocation types. |
| |
| virtual void |
| relocate_special_relocatable(const Relocate_info<size, big_endian>* |
| /*relinfo */, |
| unsigned int /* sh_type */, |
| const unsigned char* /* preloc_in */, |
| size_t /* relnum */, |
| Output_section* /* output_section */, |
| typename elfcpp::Elf_types<size>::Elf_Off |
| /* offset_in_output_section */, |
| unsigned char* /* view */, |
| typename elfcpp::Elf_types<size>::Elf_Addr |
| /* view_address */, |
| section_size_type /* view_size */, |
| unsigned char* /* preloc_out*/) |
| { gold_unreachable(); } |
| |
| // Return the number of entries in the GOT. This is only used for |
| // laying out the incremental link info sections. A target needs |
| // to implement this to support incremental linking. |
| |
| virtual unsigned int |
| got_entry_count() const |
| { gold_unreachable(); } |
| |
| // Return the number of entries in the PLT. This is only used for |
| // laying out the incremental link info sections. A target needs |
| // to implement this to support incremental linking. |
| |
| virtual unsigned int |
| plt_entry_count() const |
| { gold_unreachable(); } |
| |
| // Return the offset of the first non-reserved PLT entry. This is |
| // only used for laying out the incremental link info sections. |
| // A target needs to implement this to support incremental linking. |
| |
| virtual unsigned int |
| first_plt_entry_offset() const |
| { gold_unreachable(); } |
| |
| // Return the size of each PLT entry. This is only used for |
| // laying out the incremental link info sections. A target needs |
| // to implement this to support incremental linking. |
| |
| virtual unsigned int |
| plt_entry_size() const |
| { gold_unreachable(); } |
| |
| // Return the size of each GOT entry. This is only used for |
| // laying out the incremental link info sections. A target needs |
| // to implement this if its GOT size is different. |
| |
| virtual unsigned int |
| got_entry_size() const |
| { return size / 8; } |
| |
| // Create the GOT and PLT sections for an incremental update. |
| // A target needs to implement this to support incremental linking. |
| |
| virtual Output_data_got_base* |
| init_got_plt_for_update(Symbol_table*, |
| Layout*, |
| unsigned int /* got_count */, |
| unsigned int /* plt_count */) |
| { gold_unreachable(); } |
| |
| // Reserve a GOT entry for a local symbol, and regenerate any |
| // necessary dynamic relocations. |
| virtual void |
| reserve_local_got_entry(unsigned int /* got_index */, |
| Sized_relobj<size, big_endian>* /* obj */, |
| unsigned int /* r_sym */, |
| unsigned int /* got_type */) |
| { gold_unreachable(); } |
| |
| // Reserve a GOT entry for a global symbol, and regenerate any |
| // necessary dynamic relocations. |
| virtual void |
| reserve_global_got_entry(unsigned int /* got_index */, Symbol* /* gsym */, |
| unsigned int /* got_type */) |
| { gold_unreachable(); } |
| |
| // Register an existing PLT entry for a global symbol. |
| // A target needs to implement this to support incremental linking. |
| |
| virtual void |
| register_global_plt_entry(Symbol_table*, Layout*, |
| unsigned int /* plt_index */, |
| Symbol*) |
| { gold_unreachable(); } |
| |
| // Force a COPY relocation for a given symbol. |
| // A target needs to implement this to support incremental linking. |
| |
| virtual void |
| emit_copy_reloc(Symbol_table*, Symbol*, Output_section*, off_t) |
| { gold_unreachable(); } |
| |
| // Apply an incremental relocation. |
| |
| virtual void |
| apply_relocation(const Relocate_info<size, big_endian>* /* relinfo */, |
| typename elfcpp::Elf_types<size>::Elf_Addr /* r_offset */, |
| unsigned int /* r_type */, |
| typename elfcpp::Elf_types<size>::Elf_Swxword /* r_addend */, |
| const Symbol* /* gsym */, |
| unsigned char* /* view */, |
| typename elfcpp::Elf_types<size>::Elf_Addr /* address */, |
| section_size_type /* view_size */) |
| { gold_unreachable(); } |
| |
| // Handle target specific gc actions when adding a gc reference from |
| // SRC_OBJ, SRC_SHNDX to a location specified by DST_OBJ, DST_SHNDX |
| // and DST_OFF. |
| void |
| gc_add_reference(Symbol_table* symtab, |
| Relobj* src_obj, |
| unsigned int src_shndx, |
| Relobj* dst_obj, |
| unsigned int dst_shndx, |
| typename elfcpp::Elf_types<size>::Elf_Addr dst_off) const |
| { |
| this->do_gc_add_reference(symtab, src_obj, src_shndx, |
| dst_obj, dst_shndx, dst_off); |
| } |
| |
| // Return the r_sym field from a relocation. |
| // Most targets can use the default version of this routine, |
| // but some targets have a non-standard r_info field, and will |
| // need to provide a target-specific version. |
| virtual unsigned int |
| get_r_sym(const unsigned char* preloc) const |
| { |
| // Since REL and RELA relocs share the same structure through |
| // the r_info field, we can just use REL here. |
| elfcpp::Rel<size, big_endian> rel(preloc); |
| return elfcpp::elf_r_sym<size>(rel.get_r_info()); |
| } |
| |
| // Record a target-specific program property in the .note.gnu.property |
| // section. |
| virtual void |
| record_gnu_property(unsigned int, unsigned int, size_t, |
| const unsigned char*, const Object*) |
| { } |
| |
| // Merge the target-specific program properties from the current object. |
| virtual void |
| merge_gnu_properties(const Object*) |
| { } |
| |
| protected: |
| Sized_target(const Target::Target_info* pti) |
| : Target(pti) |
| { |
| gold_assert(pti->size == size); |
| gold_assert(pti->is_big_endian ? big_endian : !big_endian); |
| } |
| |
| // Set the EI_OSABI field if requested. |
| virtual void |
| do_adjust_elf_header(unsigned char*, int); |
| |
| // Handle target specific gc actions when adding a gc reference. |
| virtual void |
| do_gc_add_reference(Symbol_table*, Relobj*, unsigned int, |
| Relobj*, unsigned int, |
| typename elfcpp::Elf_types<size>::Elf_Addr) const |
| { } |
| |
| virtual void |
| do_function_location(Symbol_location*) const |
| { } |
| }; |
| |
| } // End namespace gold. |
| |
| #endif // !defined(GOLD_TARGET_H) |