1 // target.h -- target support for gold -*- C++ -*-
3 // Copyright (C) 2006-2014 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
23 // The abstract class Target is the interface for target specific
24 // support. It defines abstract methods which each target must
25 // implement. Typically there will be one target per processor, but
26 // in some cases it may be necessary to have subclasses.
28 // For speed and consistency we want to use inline functions to handle
29 // relocation processing. So besides implementations of the abstract
30 // methods, each target is expected to define a template
31 // specialization of the relocation functions.
38 #include "parameters.h"
46 template<int size, bool big_endian>
48 template<int size, bool big_endian>
49 class Sized_relobj_file;
50 class Relocatable_relocs;
51 template<int size, bool big_endian>
53 class Reloc_symbol_changes;
59 class Output_data_got_base;
63 struct Symbol_location;
65 // The abstract class for target specific handling.
73 // Return the bit size that this target implements. This should
77 { return this->pti_->size; }
79 // Return whether this target is big-endian.
82 { return this->pti_->is_big_endian; }
84 // Machine code to store in e_machine field of ELF header.
87 { return this->pti_->machine_code; }
89 // Processor specific flags to store in e_flags field of ELF header.
91 processor_specific_flags() const
92 { return this->processor_specific_flags_; }
94 // Whether processor specific flags are set at least once.
96 are_processor_specific_flags_set() const
97 { return this->are_processor_specific_flags_set_; }
99 // Whether this target has a specific make_symbol function.
101 has_make_symbol() const
102 { return this->pti_->has_make_symbol; }
104 // Whether this target has a specific resolve function.
107 { return this->pti_->has_resolve; }
109 // Whether this target has a specific code fill function.
111 has_code_fill() const
112 { return this->pti_->has_code_fill; }
114 // Return the default name of the dynamic linker.
116 dynamic_linker() const
117 { return this->pti_->dynamic_linker; }
119 // Return the default address to use for the text segment.
121 default_text_segment_address() const
122 { return this->pti_->default_text_segment_address; }
124 // Return the ABI specified page size.
128 if (parameters->options().max_page_size() > 0)
129 return parameters->options().max_page_size();
131 return this->pti_->abi_pagesize;
134 // Return the common page size used on actual systems.
136 common_pagesize() const
138 if (parameters->options().common_page_size() > 0)
139 return std::min(parameters->options().common_page_size(),
140 this->abi_pagesize());
142 return std::min(this->pti_->common_pagesize,
143 this->abi_pagesize());
146 // Return whether PF_X segments must contain nothing but the contents of
147 // SHF_EXECINSTR sections (no non-executable data, no headers).
149 isolate_execinstr() const
150 { return this->pti_->isolate_execinstr; }
153 rosegment_gap() const
154 { return this->pti_->rosegment_gap; }
156 // If we see some object files with .note.GNU-stack sections, and
157 // some objects files without them, this returns whether we should
158 // consider the object files without them to imply that the stack
159 // should be executable.
161 is_default_stack_executable() const
162 { return this->pti_->is_default_stack_executable; }
164 // Return a character which may appear as a prefix for a wrap
165 // symbol. If this character appears, we strip it when checking for
166 // wrapping and add it back when forming the final symbol name.
167 // This should be '\0' if not special prefix is required, which is
171 { return this->pti_->wrap_char; }
173 // Return the special section index which indicates a small common
174 // symbol. This will return SHN_UNDEF if there are no small common
177 small_common_shndx() const
178 { return this->pti_->small_common_shndx; }
180 // Return values to add to the section flags for the section holding
181 // small common symbols.
183 small_common_section_flags() const
185 gold_assert(this->pti_->small_common_shndx != elfcpp::SHN_UNDEF);
186 return this->pti_->small_common_section_flags;
189 // Return the special section index which indicates a large common
190 // symbol. This will return SHN_UNDEF if there are no large common
193 large_common_shndx() const
194 { return this->pti_->large_common_shndx; }
196 // Return values to add to the section flags for the section holding
197 // large common symbols.
199 large_common_section_flags() const
201 gold_assert(this->pti_->large_common_shndx != elfcpp::SHN_UNDEF);
202 return this->pti_->large_common_section_flags;
205 // This hook is called when an output section is created.
207 new_output_section(Output_section* os) const
208 { this->do_new_output_section(os); }
210 // This is called to tell the target to complete any sections it is
211 // handling. After this all sections must have their final size.
213 finalize_sections(Layout* layout, const Input_objects* input_objects,
214 Symbol_table* symtab)
215 { return this->do_finalize_sections(layout, input_objects, symtab); }
217 // Return the value to use for a global symbol which needs a special
218 // value in the dynamic symbol table. This will only be called if
219 // the backend first calls symbol->set_needs_dynsym_value().
221 dynsym_value(const Symbol* sym) const
222 { return this->do_dynsym_value(sym); }
224 // Return a string to use to fill out a code section. This is
225 // basically one or more NOPS which must fill out the specified
228 code_fill(section_size_type length) const
229 { return this->do_code_fill(length); }
231 // Return whether SYM is known to be defined by the ABI. This is
232 // used to avoid inappropriate warnings about undefined symbols.
234 is_defined_by_abi(const Symbol* sym) const
235 { return this->do_is_defined_by_abi(sym); }
237 // Adjust the output file header before it is written out. VIEW
238 // points to the header in external form. LEN is the length.
240 adjust_elf_header(unsigned char* view, int len)
241 { return this->do_adjust_elf_header(view, len); }
243 // Return address and size to plug into eh_frame FDEs associated with a PLT.
245 plt_fde_location(const Output_data* plt, unsigned char* oview,
246 uint64_t* address, off_t* len) const
247 { return this->do_plt_fde_location(plt, oview, address, len); }
249 // Return whether NAME is a local label name. This is used to implement the
250 // --discard-locals options.
252 is_local_label_name(const char* name) const
253 { return this->do_is_local_label_name(name); }
255 // Get the symbol index to use for a target specific reloc.
257 reloc_symbol_index(void* arg, unsigned int type) const
258 { return this->do_reloc_symbol_index(arg, type); }
260 // Get the addend to use for a target specific reloc.
262 reloc_addend(void* arg, unsigned int type, uint64_t addend) const
263 { return this->do_reloc_addend(arg, type, addend); }
265 // Return the PLT address to use for a global symbol.
267 plt_address_for_global(const Symbol* sym) const
268 { return this->do_plt_address_for_global(sym); }
270 // Return the PLT address to use for a local symbol.
272 plt_address_for_local(const Relobj* object, unsigned int symndx) const
273 { return this->do_plt_address_for_local(object, symndx); }
275 // Return the offset to use for the GOT_INDX'th got entry which is
276 // for a local tls symbol specified by OBJECT, SYMNDX.
278 tls_offset_for_local(const Relobj* object,
280 unsigned int got_indx) const
281 { return do_tls_offset_for_local(object, symndx, got_indx); }
283 // Return the offset to use for the GOT_INDX'th got entry which is
284 // for global tls symbol GSYM.
286 tls_offset_for_global(Symbol* gsym, unsigned int got_indx) const
287 { return do_tls_offset_for_global(gsym, got_indx); }
289 // For targets that use function descriptors, if LOC is the location
290 // of a function, modify it to point at the function entry location.
292 function_location(Symbol_location* loc) const
293 { return do_function_location(loc); }
295 // Return whether this target can use relocation types to determine
296 // if a function's address is taken.
298 can_check_for_function_pointers() const
299 { return this->do_can_check_for_function_pointers(); }
301 // Return whether a relocation to a merged section can be processed
302 // to retrieve the contents.
304 can_icf_inline_merge_sections () const
305 { return this->pti_->can_icf_inline_merge_sections; }
307 // Whether a section called SECTION_NAME may have function pointers to
308 // sections not eligible for safe ICF folding.
310 section_may_have_icf_unsafe_pointers(const char* section_name) const
311 { return this->do_section_may_have_icf_unsafe_pointers(section_name); }
313 // Return the base to use for the PC value in an FDE when it is
314 // encoded using DW_EH_PE_datarel. This does not appear to be
315 // documented anywhere, but it is target specific. Any use of
316 // DW_EH_PE_datarel in gcc requires defining a special macro
317 // (ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX) to output the value.
319 ehframe_datarel_base() const
320 { return this->do_ehframe_datarel_base(); }
322 // Return true if a reference to SYM from a reloc of type R_TYPE
323 // means that the current function may call an object compiled
324 // without -fsplit-stack. SYM is known to be defined in an object
325 // compiled without -fsplit-stack.
327 is_call_to_non_split(const Symbol* sym, unsigned int r_type) const
328 { return this->do_is_call_to_non_split(sym, r_type); }
330 // A function starts at OFFSET in section SHNDX in OBJECT. That
331 // function was compiled with -fsplit-stack, but it refers to a
332 // function which was compiled without -fsplit-stack. VIEW is a
333 // modifiable view of the section; VIEW_SIZE is the size of the
334 // view. The target has to adjust the function so that it allocates
337 calls_non_split(Relobj* object, unsigned int shndx,
338 section_offset_type fnoffset, section_size_type fnsize,
339 unsigned char* view, section_size_type view_size,
340 std::string* from, std::string* to) const
342 this->do_calls_non_split(object, shndx, fnoffset, fnsize, view, view_size,
346 // Make an ELF object.
347 template<int size, bool big_endian>
349 make_elf_object(const std::string& name, Input_file* input_file,
350 off_t offset, const elfcpp::Ehdr<size, big_endian>& ehdr)
351 { return this->do_make_elf_object(name, input_file, offset, ehdr); }
353 // Make an output section.
355 make_output_section(const char* name, elfcpp::Elf_Word type,
356 elfcpp::Elf_Xword flags)
357 { return this->do_make_output_section(name, type, flags); }
359 // Return true if target wants to perform relaxation.
363 // Run the dummy relaxation pass twice if relaxation debugging is enabled.
364 if (is_debugging_enabled(DEBUG_RELAXATION))
367 return this->do_may_relax();
370 // Perform a relaxation pass. Return true if layout may be changed.
372 relax(int pass, const Input_objects* input_objects, Symbol_table* symtab,
373 Layout* layout, const Task* task)
375 // Run the dummy relaxation pass twice if relaxation debugging is enabled.
376 if (is_debugging_enabled(DEBUG_RELAXATION))
379 return this->do_relax(pass, input_objects, symtab, layout, task);
382 // Return the target-specific name of attributes section. This is
383 // NULL if a target does not use attributes section or if it uses
384 // the default section name ".gnu.attributes".
386 attributes_section() const
387 { return this->pti_->attributes_section; }
389 // Return the vendor name of vendor attributes.
391 attributes_vendor() const
392 { return this->pti_->attributes_vendor; }
394 // Whether a section called NAME is an attribute section.
396 is_attributes_section(const char* name) const
398 return ((this->pti_->attributes_section != NULL
399 && strcmp(name, this->pti_->attributes_section) == 0)
400 || strcmp(name, ".gnu.attributes") == 0);
403 // Return a bit mask of argument types for attribute with TAG.
405 attribute_arg_type(int tag) const
406 { return this->do_attribute_arg_type(tag); }
408 // Return the attribute tag of the position NUM in the list of fixed
409 // attributes. Normally there is no reordering and
410 // attributes_order(NUM) == NUM.
412 attributes_order(int num) const
413 { return this->do_attributes_order(num); }
415 // When a target is selected as the default target, we call this method,
416 // which may be used for expensive, target-specific initialization.
418 select_as_default_target()
419 { this->do_select_as_default_target(); }
421 // Return the value to store in the EI_OSABI field in the ELF
425 { return this->osabi_; }
427 // Set the value to store in the EI_OSABI field in the ELF header.
429 set_osabi(elfcpp::ELFOSABI osabi)
430 { this->osabi_ = osabi; }
432 // Define target-specific standard symbols.
434 define_standard_symbols(Symbol_table* symtab, Layout* layout)
435 { this->do_define_standard_symbols(symtab, layout); }
437 // Return the output section name to use given an input section
438 // name, or NULL if no target specific name mapping is required.
439 // Set *PLEN to the length of the name if returning non-NULL.
441 output_section_name(const Relobj* relobj,
444 { return this->do_output_section_name(relobj, name, plen); }
446 // Add any special sections for this symbol to the gc work list.
448 gc_mark_symbol(Symbol_table* symtab, Symbol* sym) const
449 { this->do_gc_mark_symbol(symtab, sym); }
451 // Return the name of the entry point symbol.
453 entry_symbol_name() const
454 { return this->pti_->entry_symbol_name; }
457 // This struct holds the constant information for a child class. We
458 // use a struct to avoid the overhead of virtual function calls for
459 // simple information.
462 // Address size (32 or 64).
464 // Whether the target is big endian.
466 // The code to store in the e_machine field of the ELF header.
467 elfcpp::EM machine_code;
468 // Whether this target has a specific make_symbol function.
469 bool has_make_symbol;
470 // Whether this target has a specific resolve function.
472 // Whether this target has a specific code fill function.
474 // Whether an object file with no .note.GNU-stack sections implies
475 // that the stack should be executable.
476 bool is_default_stack_executable;
477 // Whether a relocation to a merged section can be processed to
478 // retrieve the contents.
479 bool can_icf_inline_merge_sections;
480 // Prefix character to strip when checking for wrapping.
482 // The default dynamic linker name.
483 const char* dynamic_linker;
484 // The default text segment address.
485 uint64_t default_text_segment_address;
486 // The ABI specified page size.
487 uint64_t abi_pagesize;
488 // The common page size used by actual implementations.
489 uint64_t common_pagesize;
490 // Whether PF_X segments must contain nothing but the contents of
491 // SHF_EXECINSTR sections (no non-executable data, no headers).
492 bool isolate_execinstr;
493 // If nonzero, distance from the text segment to the read-only segment.
494 uint64_t rosegment_gap;
495 // The special section index for small common symbols; SHN_UNDEF
497 elfcpp::Elf_Half small_common_shndx;
498 // The special section index for large common symbols; SHN_UNDEF
500 elfcpp::Elf_Half large_common_shndx;
501 // Section flags for small common section.
502 elfcpp::Elf_Xword small_common_section_flags;
503 // Section flags for large common section.
504 elfcpp::Elf_Xword large_common_section_flags;
505 // Name of attributes section if it is not ".gnu.attributes".
506 const char* attributes_section;
507 // Vendor name of vendor attributes.
508 const char* attributes_vendor;
509 // Name of the main entry point to the program.
510 const char* entry_symbol_name;
513 Target(const Target_info* pti)
514 : pti_(pti), processor_specific_flags_(0),
515 are_processor_specific_flags_set_(false), osabi_(elfcpp::ELFOSABI_NONE)
518 // Virtual function which may be implemented by the child class.
520 do_new_output_section(Output_section*) const
523 // Virtual function which may be implemented by the child class.
525 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*)
528 // Virtual function which may be implemented by the child class.
530 do_dynsym_value(const Symbol*) const
531 { gold_unreachable(); }
533 // Virtual function which must be implemented by the child class if
536 do_code_fill(section_size_type) const
537 { gold_unreachable(); }
539 // Virtual function which may be implemented by the child class.
541 do_is_defined_by_abi(const Symbol*) const
544 // Adjust the output file header before it is written out. VIEW
545 // points to the header in external form. LEN is the length, and
546 // will be one of the values of elfcpp::Elf_sizes<size>::ehdr_size.
547 // By default, we set the EI_OSABI field if requested (in
550 do_adjust_elf_header(unsigned char*, int) = 0;
552 // Return address and size to plug into eh_frame FDEs associated with a PLT.
554 do_plt_fde_location(const Output_data* plt, unsigned char* oview,
555 uint64_t* address, off_t* len) const;
557 // Virtual function which may be overridden by the child class.
559 do_is_local_label_name(const char*) const;
561 // Virtual function that must be overridden by a target which uses
562 // target specific relocations.
564 do_reloc_symbol_index(void*, unsigned int) const
565 { gold_unreachable(); }
567 // Virtual function that must be overridden by a target which uses
568 // target specific relocations.
570 do_reloc_addend(void*, unsigned int, uint64_t) const
571 { gold_unreachable(); }
573 // Virtual functions that must be overridden by a target that uses
574 // STT_GNU_IFUNC symbols.
576 do_plt_address_for_global(const Symbol*) const
577 { gold_unreachable(); }
580 do_plt_address_for_local(const Relobj*, unsigned int) const
581 { gold_unreachable(); }
584 do_tls_offset_for_local(const Relobj*, unsigned int, unsigned int) const
585 { gold_unreachable(); }
588 do_tls_offset_for_global(Symbol*, unsigned int) const
589 { gold_unreachable(); }
592 do_function_location(Symbol_location*) const = 0;
594 // Virtual function which may be overriden by the child class.
596 do_can_check_for_function_pointers() const
599 // Virtual function which may be overridden by the child class. We
600 // recognize some default sections for which we don't care whether
601 // they have function pointers.
603 do_section_may_have_icf_unsafe_pointers(const char* section_name) const
605 // We recognize sections for normal vtables, construction vtables and
607 return (!is_prefix_of(".rodata._ZTV", section_name)
608 && !is_prefix_of(".data.rel.ro._ZTV", section_name)
609 && !is_prefix_of(".rodata._ZTC", section_name)
610 && !is_prefix_of(".data.rel.ro._ZTC", section_name)
611 && !is_prefix_of(".eh_frame", section_name));
615 do_ehframe_datarel_base() const
616 { gold_unreachable(); }
618 // Virtual function which may be overridden by the child class. The
619 // default implementation is that any function not defined by the
620 // ABI is a call to a non-split function.
622 do_is_call_to_non_split(const Symbol* sym, unsigned int) const;
624 // Virtual function which may be overridden by the child class.
626 do_calls_non_split(Relobj* object, unsigned int, section_offset_type,
627 section_size_type, unsigned char*, section_size_type,
628 std::string*, std::string*) const;
630 // make_elf_object hooks. There are four versions of these for
631 // different address sizes and endianness.
633 // Set processor specific flags.
635 set_processor_specific_flags(elfcpp::Elf_Word flags)
637 this->processor_specific_flags_ = flags;
638 this->are_processor_specific_flags_set_ = true;
641 #ifdef HAVE_TARGET_32_LITTLE
642 // Virtual functions which may be overridden by the child class.
644 do_make_elf_object(const std::string&, Input_file*, off_t,
645 const elfcpp::Ehdr<32, false>&);
648 #ifdef HAVE_TARGET_32_BIG
649 // Virtual functions which may be overridden by the child class.
651 do_make_elf_object(const std::string&, Input_file*, off_t,
652 const elfcpp::Ehdr<32, true>&);
655 #ifdef HAVE_TARGET_64_LITTLE
656 // Virtual functions which may be overridden by the child class.
658 do_make_elf_object(const std::string&, Input_file*, off_t,
659 const elfcpp::Ehdr<64, false>& ehdr);
662 #ifdef HAVE_TARGET_64_BIG
663 // Virtual functions which may be overridden by the child class.
665 do_make_elf_object(const std::string& name, Input_file* input_file,
666 off_t offset, const elfcpp::Ehdr<64, true>& ehdr);
669 // Virtual functions which may be overridden by the child class.
670 virtual Output_section*
671 do_make_output_section(const char* name, elfcpp::Elf_Word type,
672 elfcpp::Elf_Xword flags);
674 // Virtual function which may be overridden by the child class.
677 { return parameters->options().relax(); }
679 // Virtual function which may be overridden by the child class.
681 do_relax(int, const Input_objects*, Symbol_table*, Layout*, const Task*)
684 // A function for targets to call. Return whether BYTES/LEN matches
685 // VIEW/VIEW_SIZE at OFFSET.
687 match_view(const unsigned char* view, section_size_type view_size,
688 section_offset_type offset, const char* bytes, size_t len) const;
690 // Set the contents of a VIEW/VIEW_SIZE to nops starting at OFFSET
693 set_view_to_nop(unsigned char* view, section_size_type view_size,
694 section_offset_type offset, size_t len) const;
696 // This must be overridden by the child class if it has target-specific
697 // attributes subsection in the attribute section.
699 do_attribute_arg_type(int) const
700 { gold_unreachable(); }
702 // This may be overridden by the child class.
704 do_attributes_order(int num) const
707 // This may be overridden by the child class.
709 do_select_as_default_target()
712 // This may be overridden by the child class.
714 do_define_standard_symbols(Symbol_table*, Layout*)
717 // This may be overridden by the child class.
719 do_output_section_name(const Relobj*, const char*, size_t*) const
722 // This may be overridden by the child class.
724 do_gc_mark_symbol(Symbol_table*, Symbol*) const
728 // The implementations of the four do_make_elf_object virtual functions are
729 // almost identical except for their sizes and endianness. We use a template.
730 // for their implementations.
731 template<int size, bool big_endian>
733 do_make_elf_object_implementation(const std::string&, Input_file*, off_t,
734 const elfcpp::Ehdr<size, big_endian>&);
736 Target(const Target&);
737 Target& operator=(const Target&);
739 // The target information.
740 const Target_info* pti_;
741 // Processor-specific flags.
742 elfcpp::Elf_Word processor_specific_flags_;
743 // Whether the processor-specific flags are set at least once.
744 bool are_processor_specific_flags_set_;
745 // If not ELFOSABI_NONE, the value to put in the EI_OSABI field of
746 // the ELF header. This is handled at this level because it is
747 // OS-specific rather than processor-specific.
748 elfcpp::ELFOSABI osabi_;
751 // The abstract class for a specific size and endianness of target.
752 // Each actual target implementation class should derive from an
753 // instantiation of Sized_target.
755 template<int size, bool big_endian>
756 class Sized_target : public Target
759 // Make a new symbol table entry for the target. This should be
760 // overridden by a target which needs additional information in the
761 // symbol table. This will only be called if has_make_symbol()
763 virtual Sized_symbol<size>*
765 { gold_unreachable(); }
767 // Resolve a symbol for the target. This should be overridden by a
768 // target which needs to take special action. TO is the
769 // pre-existing symbol. SYM is the new symbol, seen in OBJECT.
770 // VERSION is the version of SYM. This will only be called if
771 // has_resolve() returns true.
773 resolve(Symbol*, const elfcpp::Sym<size, big_endian>&, Object*,
775 { gold_unreachable(); }
777 // Process the relocs for a section, and record information of the
778 // mapping from source to destination sections. This mapping is later
779 // used to determine unreferenced garbage sections. This procedure is
780 // only called during garbage collection.
782 gc_process_relocs(Symbol_table* symtab,
784 Sized_relobj_file<size, big_endian>* object,
785 unsigned int data_shndx,
786 unsigned int sh_type,
787 const unsigned char* prelocs,
789 Output_section* output_section,
790 bool needs_special_offset_handling,
791 size_t local_symbol_count,
792 const unsigned char* plocal_symbols) = 0;
794 // Scan the relocs for a section, and record any information
795 // required for the symbol. SYMTAB is the symbol table. OBJECT is
796 // the object in which the section appears. DATA_SHNDX is the
797 // section index that these relocs apply to. SH_TYPE is the type of
798 // the relocation section, SHT_REL or SHT_RELA. PRELOCS points to
799 // the relocation data. RELOC_COUNT is the number of relocs.
800 // LOCAL_SYMBOL_COUNT is the number of local symbols.
801 // OUTPUT_SECTION is the output section.
802 // NEEDS_SPECIAL_OFFSET_HANDLING is true if offsets to the output
803 // sections are not mapped as usual. PLOCAL_SYMBOLS points to the
804 // local symbol data from OBJECT. GLOBAL_SYMBOLS is the array of
805 // pointers to the global symbol table from OBJECT.
807 scan_relocs(Symbol_table* symtab,
809 Sized_relobj_file<size, big_endian>* object,
810 unsigned int data_shndx,
811 unsigned int sh_type,
812 const unsigned char* prelocs,
814 Output_section* output_section,
815 bool needs_special_offset_handling,
816 size_t local_symbol_count,
817 const unsigned char* plocal_symbols) = 0;
819 // Relocate section data. SH_TYPE is the type of the relocation
820 // section, SHT_REL or SHT_RELA. PRELOCS points to the relocation
821 // information. RELOC_COUNT is the number of relocs.
822 // OUTPUT_SECTION is the output section.
823 // NEEDS_SPECIAL_OFFSET_HANDLING is true if offsets must be mapped
824 // to correspond to the output section. VIEW is a view into the
825 // output file holding the section contents, VIEW_ADDRESS is the
826 // virtual address of the view, and VIEW_SIZE is the size of the
827 // view. If NEEDS_SPECIAL_OFFSET_HANDLING is true, the VIEW_xx
828 // parameters refer to the complete output section data, not just
829 // the input section data.
831 relocate_section(const Relocate_info<size, big_endian>*,
832 unsigned int sh_type,
833 const unsigned char* prelocs,
835 Output_section* output_section,
836 bool needs_special_offset_handling,
838 typename elfcpp::Elf_types<size>::Elf_Addr view_address,
839 section_size_type view_size,
840 const Reloc_symbol_changes*) = 0;
842 // Scan the relocs during a relocatable link. The parameters are
843 // like scan_relocs, with an additional Relocatable_relocs
844 // parameter, used to record the disposition of the relocs.
846 scan_relocatable_relocs(Symbol_table* symtab,
848 Sized_relobj_file<size, big_endian>* object,
849 unsigned int data_shndx,
850 unsigned int sh_type,
851 const unsigned char* prelocs,
853 Output_section* output_section,
854 bool needs_special_offset_handling,
855 size_t local_symbol_count,
856 const unsigned char* plocal_symbols,
857 Relocatable_relocs*) = 0;
859 // Emit relocations for a section during a relocatable link, and for
860 // --emit-relocs. The parameters are like relocate_section, with
861 // additional parameters for the view of the output reloc section.
863 relocate_relocs(const Relocate_info<size, big_endian>*,
864 unsigned int sh_type,
865 const unsigned char* prelocs,
867 Output_section* output_section,
868 typename elfcpp::Elf_types<size>::Elf_Off
869 offset_in_output_section,
870 const Relocatable_relocs*,
872 typename elfcpp::Elf_types<size>::Elf_Addr view_address,
873 section_size_type view_size,
874 unsigned char* reloc_view,
875 section_size_type reloc_view_size) = 0;
877 // Perform target-specific processing in a relocatable link. This is
878 // only used if we use the relocation strategy RELOC_SPECIAL.
879 // RELINFO points to a Relocation_info structure. SH_TYPE is the relocation
880 // section type. PRELOC_IN points to the original relocation. RELNUM is
881 // the index number of the relocation in the relocation section.
882 // OUTPUT_SECTION is the output section to which the relocation is applied.
883 // OFFSET_IN_OUTPUT_SECTION is the offset of the relocation input section
884 // within the output section. VIEW points to the output view of the
885 // output section. VIEW_ADDRESS is output address of the view. VIEW_SIZE
886 // is the size of the output view and PRELOC_OUT points to the new
887 // relocation in the output object.
889 // A target only needs to override this if the generic code in
890 // target-reloc.h cannot handle some relocation types.
893 relocate_special_relocatable(const Relocate_info<size, big_endian>*
895 unsigned int /* sh_type */,
896 const unsigned char* /* preloc_in */,
898 Output_section* /* output_section */,
899 typename elfcpp::Elf_types<size>::Elf_Off
900 /* offset_in_output_section */,
901 unsigned char* /* view */,
902 typename elfcpp::Elf_types<size>::Elf_Addr
904 section_size_type /* view_size */,
905 unsigned char* /* preloc_out*/)
906 { gold_unreachable(); }
908 // Return the number of entries in the GOT. This is only used for
909 // laying out the incremental link info sections. A target needs
910 // to implement this to support incremental linking.
913 got_entry_count() const
914 { gold_unreachable(); }
916 // Return the number of entries in the PLT. This is only used for
917 // laying out the incremental link info sections. A target needs
918 // to implement this to support incremental linking.
921 plt_entry_count() const
922 { gold_unreachable(); }
924 // Return the offset of the first non-reserved PLT entry. This is
925 // only used for laying out the incremental link info sections.
926 // A target needs to implement this to support incremental linking.
929 first_plt_entry_offset() const
930 { gold_unreachable(); }
932 // Return the size of each PLT entry. This is only used for
933 // laying out the incremental link info sections. A target needs
934 // to implement this to support incremental linking.
937 plt_entry_size() const
938 { gold_unreachable(); }
940 // Create the GOT and PLT sections for an incremental update.
941 // A target needs to implement this to support incremental linking.
943 virtual Output_data_got_base*
944 init_got_plt_for_update(Symbol_table*,
946 unsigned int /* got_count */,
947 unsigned int /* plt_count */)
948 { gold_unreachable(); }
950 // Reserve a GOT entry for a local symbol, and regenerate any
951 // necessary dynamic relocations.
953 reserve_local_got_entry(unsigned int /* got_index */,
954 Sized_relobj<size, big_endian>* /* obj */,
955 unsigned int /* r_sym */,
956 unsigned int /* got_type */)
957 { gold_unreachable(); }
959 // Reserve a GOT entry for a global symbol, and regenerate any
960 // necessary dynamic relocations.
962 reserve_global_got_entry(unsigned int /* got_index */, Symbol* /* gsym */,
963 unsigned int /* got_type */)
964 { gold_unreachable(); }
966 // Register an existing PLT entry for a global symbol.
967 // A target needs to implement this to support incremental linking.
970 register_global_plt_entry(Symbol_table*, Layout*,
971 unsigned int /* plt_index */,
973 { gold_unreachable(); }
975 // Force a COPY relocation for a given symbol.
976 // A target needs to implement this to support incremental linking.
979 emit_copy_reloc(Symbol_table*, Symbol*, Output_section*, off_t)
980 { gold_unreachable(); }
982 // Apply an incremental relocation.
985 apply_relocation(const Relocate_info<size, big_endian>* /* relinfo */,
986 typename elfcpp::Elf_types<size>::Elf_Addr /* r_offset */,
987 unsigned int /* r_type */,
988 typename elfcpp::Elf_types<size>::Elf_Swxword /* r_addend */,
989 const Symbol* /* gsym */,
990 unsigned char* /* view */,
991 typename elfcpp::Elf_types<size>::Elf_Addr /* address */,
992 section_size_type /* view_size */)
993 { gold_unreachable(); }
995 // Handle target specific gc actions when adding a gc reference from
996 // SRC_OBJ, SRC_SHNDX to a location specified by DST_OBJ, DST_SHNDX
999 gc_add_reference(Symbol_table* symtab,
1001 unsigned int src_shndx,
1003 unsigned int dst_shndx,
1004 typename elfcpp::Elf_types<size>::Elf_Addr dst_off) const
1006 this->do_gc_add_reference(symtab, src_obj, src_shndx,
1007 dst_obj, dst_shndx, dst_off);
1011 Sized_target(const Target::Target_info* pti)
1014 gold_assert(pti->size == size);
1015 gold_assert(pti->is_big_endian ? big_endian : !big_endian);
1018 // Set the EI_OSABI field if requested.
1020 do_adjust_elf_header(unsigned char*, int);
1022 // Handle target specific gc actions when adding a gc reference.
1024 do_gc_add_reference(Symbol_table*, Object*, unsigned int,
1025 Object*, unsigned int,
1026 typename elfcpp::Elf_types<size>::Elf_Addr) const
1030 do_function_location(Symbol_location*) const
1034 } // End namespace gold.
1036 #endif // !defined(GOLD_TARGET_H)