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- // target.h -- target support for gold -*- C++ -*-
- // Copyright (C) 2006-2022 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)
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