1 // target.h -- target support for gold -*- C++ -*-
3 // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012
4 // Free Software Foundation, Inc.
5 // Written by Ian Lance Taylor <iant@google.com>.
7 // This file is part of gold.
9 // This program is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation; either version 3 of the License, or
12 // (at your option) any later version.
14 // This program is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 // GNU General Public License for more details.
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
22 // MA 02110-1301, USA.
24 // The abstract class Target is the interface for target specific
25 // support. It defines abstract methods which each target must
26 // implement. Typically there will be one target per processor, but
27 // in some cases it may be necessary to have subclasses.
29 // For speed and consistency we want to use inline functions to handle
30 // relocation processing. So besides implementations of the abstract
31 // methods, each target is expected to define a template
32 // specialization of the relocation functions.
39 #include "parameters.h"
47 template<int size
, bool big_endian
>
49 template<int size
, bool big_endian
>
50 class Sized_relobj_file
;
51 class Relocatable_relocs
;
52 template<int size
, bool big_endian
>
54 class Reloc_symbol_changes
;
60 class Output_data_got_base
;
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
) const
241 { return this->do_adjust_elf_header(view
, len
); }
243 // Return whether NAME is a local label name. This is used to implement the
244 // --discard-locals options.
246 is_local_label_name(const char* name
) const
247 { return this->do_is_local_label_name(name
); }
249 // Get the symbol index to use for a target specific reloc.
251 reloc_symbol_index(void* arg
, unsigned int type
) const
252 { return this->do_reloc_symbol_index(arg
, type
); }
254 // Get the addend to use for a target specific reloc.
256 reloc_addend(void* arg
, unsigned int type
, uint64_t addend
) const
257 { return this->do_reloc_addend(arg
, type
, addend
); }
259 // Return the PLT address to use for a global symbol. This is used
260 // for STT_GNU_IFUNC symbols. The symbol's plt_offset is relative
261 // to this PLT address.
263 plt_address_for_global(const Symbol
* sym
) const
264 { return this->do_plt_address_for_global(sym
); }
266 // Return the PLT address to use for a local symbol. This is used
267 // for STT_GNU_IFUNC symbols. The symbol's plt_offset is relative
268 // to this PLT address.
270 plt_address_for_local(const Relobj
* object
, unsigned int symndx
) const
271 { return this->do_plt_address_for_local(object
, symndx
); }
273 // Return the offset to use for the GOT_INDX'th got entry which is
274 // for a local tls symbol specified by OBJECT, SYMNDX.
276 tls_offset_for_local(const Relobj
* object
,
278 unsigned int got_indx
) const
279 { return do_tls_offset_for_local(object
, symndx
, got_indx
); }
281 // Return the offset to use for the GOT_INDX'th got entry which is
282 // for global tls symbol GSYM.
284 tls_offset_for_global(Symbol
* gsym
, unsigned int got_indx
) const
285 { return do_tls_offset_for_global(gsym
, got_indx
); }
287 // Return whether this target can use relocation types to determine
288 // if a function's address is taken.
290 can_check_for_function_pointers() const
291 { return this->do_can_check_for_function_pointers(); }
293 // Return whether a relocation to a merged section can be processed
294 // to retrieve the contents.
296 can_icf_inline_merge_sections () const
297 { return this->pti_
->can_icf_inline_merge_sections
; }
299 // Whether a section called SECTION_NAME may have function pointers to
300 // sections not eligible for safe ICF folding.
302 section_may_have_icf_unsafe_pointers(const char* section_name
) const
303 { return this->do_section_may_have_icf_unsafe_pointers(section_name
); }
305 // Return the base to use for the PC value in an FDE when it is
306 // encoded using DW_EH_PE_datarel. This does not appear to be
307 // documented anywhere, but it is target specific. Any use of
308 // DW_EH_PE_datarel in gcc requires defining a special macro
309 // (ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX) to output the value.
311 ehframe_datarel_base() const
312 { return this->do_ehframe_datarel_base(); }
314 // Return true if a reference to SYM from a reloc of type R_TYPE
315 // means that the current function may call an object compiled
316 // without -fsplit-stack. SYM is known to be defined in an object
317 // compiled without -fsplit-stack.
319 is_call_to_non_split(const Symbol
* sym
, unsigned int r_type
) const
320 { return this->do_is_call_to_non_split(sym
, r_type
); }
322 // A function starts at OFFSET in section SHNDX in OBJECT. That
323 // function was compiled with -fsplit-stack, but it refers to a
324 // function which was compiled without -fsplit-stack. VIEW is a
325 // modifiable view of the section; VIEW_SIZE is the size of the
326 // view. The target has to adjust the function so that it allocates
329 calls_non_split(Relobj
* object
, unsigned int shndx
,
330 section_offset_type fnoffset
, section_size_type fnsize
,
331 unsigned char* view
, section_size_type view_size
,
332 std::string
* from
, std::string
* to
) const
334 this->do_calls_non_split(object
, shndx
, fnoffset
, fnsize
, view
, view_size
,
338 // Make an ELF object.
339 template<int size
, bool big_endian
>
341 make_elf_object(const std::string
& name
, Input_file
* input_file
,
342 off_t offset
, const elfcpp::Ehdr
<size
, big_endian
>& ehdr
)
343 { return this->do_make_elf_object(name
, input_file
, offset
, ehdr
); }
345 // Make an output section.
347 make_output_section(const char* name
, elfcpp::Elf_Word type
,
348 elfcpp::Elf_Xword flags
)
349 { return this->do_make_output_section(name
, type
, flags
); }
351 // Return true if target wants to perform relaxation.
355 // Run the dummy relaxation pass twice if relaxation debugging is enabled.
356 if (is_debugging_enabled(DEBUG_RELAXATION
))
359 return this->do_may_relax();
362 // Perform a relaxation pass. Return true if layout may be changed.
364 relax(int pass
, const Input_objects
* input_objects
, Symbol_table
* symtab
,
365 Layout
* layout
, const Task
* task
)
367 // Run the dummy relaxation pass twice if relaxation debugging is enabled.
368 if (is_debugging_enabled(DEBUG_RELAXATION
))
371 return this->do_relax(pass
, input_objects
, symtab
, layout
, task
);
374 // Return the target-specific name of attributes section. This is
375 // NULL if a target does not use attributes section or if it uses
376 // the default section name ".gnu.attributes".
378 attributes_section() const
379 { return this->pti_
->attributes_section
; }
381 // Return the vendor name of vendor attributes.
383 attributes_vendor() const
384 { return this->pti_
->attributes_vendor
; }
386 // Whether a section called NAME is an attribute section.
388 is_attributes_section(const char* name
) const
390 return ((this->pti_
->attributes_section
!= NULL
391 && strcmp(name
, this->pti_
->attributes_section
) == 0)
392 || strcmp(name
, ".gnu.attributes") == 0);
395 // Return a bit mask of argument types for attribute with TAG.
397 attribute_arg_type(int tag
) const
398 { return this->do_attribute_arg_type(tag
); }
400 // Return the attribute tag of the position NUM in the list of fixed
401 // attributes. Normally there is no reordering and
402 // attributes_order(NUM) == NUM.
404 attributes_order(int num
) const
405 { return this->do_attributes_order(num
); }
407 // When a target is selected as the default target, we call this method,
408 // which may be used for expensive, target-specific initialization.
410 select_as_default_target()
411 { this->do_select_as_default_target(); }
413 // Return the value to store in the EI_OSABI field in the ELF
417 { return this->osabi_
; }
419 // Set the value to store in the EI_OSABI field in the ELF header.
421 set_osabi(elfcpp::ELFOSABI osabi
)
422 { this->osabi_
= osabi
; }
424 // Define target-specific standard symbols.
426 define_standard_symbols(Symbol_table
* symtab
, Layout
* layout
)
427 { this->do_define_standard_symbols(symtab
, layout
); }
429 // Return the output section name to use given an input section
430 // name, or NULL if no target specific name mapping is required.
431 // Set *PLEN to the length of the name if returning non-NULL.
433 output_section_name(const Relobj
* relobj
,
436 { return this->do_output_section_name(relobj
, name
, plen
); }
438 // Add any special sections for this symbol to the gc work list.
440 gc_mark_symbol(Symbol_table
* symtab
, Symbol
* sym
) const
441 { this->do_gc_mark_symbol(symtab
, sym
); }
444 // This struct holds the constant information for a child class. We
445 // use a struct to avoid the overhead of virtual function calls for
446 // simple information.
449 // Address size (32 or 64).
451 // Whether the target is big endian.
453 // The code to store in the e_machine field of the ELF header.
454 elfcpp::EM machine_code
;
455 // Whether this target has a specific make_symbol function.
456 bool has_make_symbol
;
457 // Whether this target has a specific resolve function.
459 // Whether this target has a specific code fill function.
461 // Whether an object file with no .note.GNU-stack sections implies
462 // that the stack should be executable.
463 bool is_default_stack_executable
;
464 // Whether a relocation to a merged section can be processed to
465 // retrieve the contents.
466 bool can_icf_inline_merge_sections
;
467 // Prefix character to strip when checking for wrapping.
469 // The default dynamic linker name.
470 const char* dynamic_linker
;
471 // The default text segment address.
472 uint64_t default_text_segment_address
;
473 // The ABI specified page size.
474 uint64_t abi_pagesize
;
475 // The common page size used by actual implementations.
476 uint64_t common_pagesize
;
477 // Whether PF_X segments must contain nothing but the contents of
478 // SHF_EXECINSTR sections (no non-executable data, no headers).
479 bool isolate_execinstr
;
480 // If nonzero, distance from the text segment to the read-only segment.
481 uint64_t rosegment_gap
;
482 // The special section index for small common symbols; SHN_UNDEF
484 elfcpp::Elf_Half small_common_shndx
;
485 // The special section index for large common symbols; SHN_UNDEF
487 elfcpp::Elf_Half large_common_shndx
;
488 // Section flags for small common section.
489 elfcpp::Elf_Xword small_common_section_flags
;
490 // Section flags for large common section.
491 elfcpp::Elf_Xword large_common_section_flags
;
492 // Name of attributes section if it is not ".gnu.attributes".
493 const char* attributes_section
;
494 // Vendor name of vendor attributes.
495 const char* attributes_vendor
;
498 Target(const Target_info
* pti
)
499 : pti_(pti
), processor_specific_flags_(0),
500 are_processor_specific_flags_set_(false), osabi_(elfcpp::ELFOSABI_NONE
)
503 // Virtual function which may be implemented by the child class.
505 do_new_output_section(Output_section
*) const
508 // Virtual function which may be implemented by the child class.
510 do_finalize_sections(Layout
*, const Input_objects
*, Symbol_table
*)
513 // Virtual function which may be implemented by the child class.
515 do_dynsym_value(const Symbol
*) const
516 { gold_unreachable(); }
518 // Virtual function which must be implemented by the child class if
521 do_code_fill(section_size_type
) const
522 { gold_unreachable(); }
524 // Virtual function which may be implemented by the child class.
526 do_is_defined_by_abi(const Symbol
*) const
529 // Adjust the output file header before it is written out. VIEW
530 // points to the header in external form. LEN is the length, and
531 // will be one of the values of elfcpp::Elf_sizes<size>::ehdr_size.
532 // By default, we set the EI_OSABI field if requested (in
535 do_adjust_elf_header(unsigned char*, int) const = 0;
537 // Virtual function which may be overridden by the child class.
539 do_is_local_label_name(const char*) const;
541 // Virtual function that must be overridden by a target which uses
542 // target specific relocations.
544 do_reloc_symbol_index(void*, unsigned int) const
545 { gold_unreachable(); }
547 // Virtual function that must be overridden by a target which uses
548 // target specific relocations.
550 do_reloc_addend(void*, unsigned int, uint64_t) const
551 { gold_unreachable(); }
553 // Virtual functions that must be overridden by a target that uses
554 // STT_GNU_IFUNC symbols.
556 do_plt_address_for_global(const Symbol
*) const
557 { gold_unreachable(); }
560 do_plt_address_for_local(const Relobj
*, unsigned int) const
561 { gold_unreachable(); }
564 do_tls_offset_for_local(const Relobj
*, unsigned int, unsigned int) const
565 { gold_unreachable(); }
568 do_tls_offset_for_global(Symbol
*, unsigned int) const
569 { gold_unreachable(); }
571 // Virtual function which may be overriden by the child class.
573 do_can_check_for_function_pointers() const
576 // Virtual function which may be overridden by the child class. We
577 // recognize some default sections for which we don't care whether
578 // they have function pointers.
580 do_section_may_have_icf_unsafe_pointers(const char* section_name
) const
582 // We recognize sections for normal vtables, construction vtables and
584 return (!is_prefix_of(".rodata._ZTV", section_name
)
585 && !is_prefix_of(".data.rel.ro._ZTV", section_name
)
586 && !is_prefix_of(".rodata._ZTC", section_name
)
587 && !is_prefix_of(".data.rel.ro._ZTC", section_name
)
588 && !is_prefix_of(".eh_frame", section_name
));
592 do_ehframe_datarel_base() const
593 { gold_unreachable(); }
595 // Virtual function which may be overridden by the child class. The
596 // default implementation is that any function not defined by the
597 // ABI is a call to a non-split function.
599 do_is_call_to_non_split(const Symbol
* sym
, unsigned int) const;
601 // Virtual function which may be overridden by the child class.
603 do_calls_non_split(Relobj
* object
, unsigned int, section_offset_type
,
604 section_size_type
, unsigned char*, section_size_type
,
605 std::string
*, std::string
*) const;
607 // make_elf_object hooks. There are four versions of these for
608 // different address sizes and endianness.
610 // Set processor specific flags.
612 set_processor_specific_flags(elfcpp::Elf_Word flags
)
614 this->processor_specific_flags_
= flags
;
615 this->are_processor_specific_flags_set_
= true;
618 #ifdef HAVE_TARGET_32_LITTLE
619 // Virtual functions which may be overridden by the child class.
621 do_make_elf_object(const std::string
&, Input_file
*, off_t
,
622 const elfcpp::Ehdr
<32, false>&);
625 #ifdef HAVE_TARGET_32_BIG
626 // Virtual functions which may be overridden by the child class.
628 do_make_elf_object(const std::string
&, Input_file
*, off_t
,
629 const elfcpp::Ehdr
<32, true>&);
632 #ifdef HAVE_TARGET_64_LITTLE
633 // Virtual functions which may be overridden by the child class.
635 do_make_elf_object(const std::string
&, Input_file
*, off_t
,
636 const elfcpp::Ehdr
<64, false>& ehdr
);
639 #ifdef HAVE_TARGET_64_BIG
640 // Virtual functions which may be overridden by the child class.
642 do_make_elf_object(const std::string
& name
, Input_file
* input_file
,
643 off_t offset
, const elfcpp::Ehdr
<64, true>& ehdr
);
646 // Virtual functions which may be overridden by the child class.
647 virtual Output_section
*
648 do_make_output_section(const char* name
, elfcpp::Elf_Word type
,
649 elfcpp::Elf_Xword flags
);
651 // Virtual function which may be overridden by the child class.
654 { return parameters
->options().relax(); }
656 // Virtual function which may be overridden by the child class.
658 do_relax(int, const Input_objects
*, Symbol_table
*, Layout
*, const Task
*)
661 // A function for targets to call. Return whether BYTES/LEN matches
662 // VIEW/VIEW_SIZE at OFFSET.
664 match_view(const unsigned char* view
, section_size_type view_size
,
665 section_offset_type offset
, const char* bytes
, size_t len
) const;
667 // Set the contents of a VIEW/VIEW_SIZE to nops starting at OFFSET
670 set_view_to_nop(unsigned char* view
, section_size_type view_size
,
671 section_offset_type offset
, size_t len
) const;
673 // This must be overridden by the child class if it has target-specific
674 // attributes subsection in the attribute section.
676 do_attribute_arg_type(int) const
677 { gold_unreachable(); }
679 // This may be overridden by the child class.
681 do_attributes_order(int num
) const
684 // This may be overridden by the child class.
686 do_select_as_default_target()
689 // This may be overridden by the child class.
691 do_define_standard_symbols(Symbol_table
*, Layout
*)
694 // This may be overridden by the child class.
696 do_output_section_name(const Relobj
*, const char*, size_t*) const
699 // This may be overridden by the child class.
701 do_gc_mark_symbol(Symbol_table
*, Symbol
*) const
705 // The implementations of the four do_make_elf_object virtual functions are
706 // almost identical except for their sizes and endianness. We use a template.
707 // for their implementations.
708 template<int size
, bool big_endian
>
710 do_make_elf_object_implementation(const std::string
&, Input_file
*, off_t
,
711 const elfcpp::Ehdr
<size
, big_endian
>&);
713 Target(const Target
&);
714 Target
& operator=(const Target
&);
716 // The target information.
717 const Target_info
* pti_
;
718 // Processor-specific flags.
719 elfcpp::Elf_Word processor_specific_flags_
;
720 // Whether the processor-specific flags are set at least once.
721 bool are_processor_specific_flags_set_
;
722 // If not ELFOSABI_NONE, the value to put in the EI_OSABI field of
723 // the ELF header. This is handled at this level because it is
724 // OS-specific rather than processor-specific.
725 elfcpp::ELFOSABI osabi_
;
728 // The abstract class for a specific size and endianness of target.
729 // Each actual target implementation class should derive from an
730 // instantiation of Sized_target.
732 template<int size
, bool big_endian
>
733 class Sized_target
: public Target
736 // Make a new symbol table entry for the target. This should be
737 // overridden by a target which needs additional information in the
738 // symbol table. This will only be called if has_make_symbol()
740 virtual Sized_symbol
<size
>*
742 { gold_unreachable(); }
744 // Resolve a symbol for the target. This should be overridden by a
745 // target which needs to take special action. TO is the
746 // pre-existing symbol. SYM is the new symbol, seen in OBJECT.
747 // VERSION is the version of SYM. This will only be called if
748 // has_resolve() returns true.
750 resolve(Symbol
*, const elfcpp::Sym
<size
, big_endian
>&, Object
*,
752 { gold_unreachable(); }
754 // Process the relocs for a section, and record information of the
755 // mapping from source to destination sections. This mapping is later
756 // used to determine unreferenced garbage sections. This procedure is
757 // only called during garbage collection.
759 gc_process_relocs(Symbol_table
* symtab
,
761 Sized_relobj_file
<size
, big_endian
>* object
,
762 unsigned int data_shndx
,
763 unsigned int sh_type
,
764 const unsigned char* prelocs
,
766 Output_section
* output_section
,
767 bool needs_special_offset_handling
,
768 size_t local_symbol_count
,
769 const unsigned char* plocal_symbols
) = 0;
771 // Scan the relocs for a section, and record any information
772 // required for the symbol. SYMTAB is the symbol table. OBJECT is
773 // the object in which the section appears. DATA_SHNDX is the
774 // section index that these relocs apply to. SH_TYPE is the type of
775 // the relocation section, SHT_REL or SHT_RELA. PRELOCS points to
776 // the relocation data. RELOC_COUNT is the number of relocs.
777 // LOCAL_SYMBOL_COUNT is the number of local symbols.
778 // OUTPUT_SECTION is the output section.
779 // NEEDS_SPECIAL_OFFSET_HANDLING is true if offsets to the output
780 // sections are not mapped as usual. PLOCAL_SYMBOLS points to the
781 // local symbol data from OBJECT. GLOBAL_SYMBOLS is the array of
782 // pointers to the global symbol table from OBJECT.
784 scan_relocs(Symbol_table
* symtab
,
786 Sized_relobj_file
<size
, big_endian
>* object
,
787 unsigned int data_shndx
,
788 unsigned int sh_type
,
789 const unsigned char* prelocs
,
791 Output_section
* output_section
,
792 bool needs_special_offset_handling
,
793 size_t local_symbol_count
,
794 const unsigned char* plocal_symbols
) = 0;
796 // Relocate section data. SH_TYPE is the type of the relocation
797 // section, SHT_REL or SHT_RELA. PRELOCS points to the relocation
798 // information. RELOC_COUNT is the number of relocs.
799 // OUTPUT_SECTION is the output section.
800 // NEEDS_SPECIAL_OFFSET_HANDLING is true if offsets must be mapped
801 // to correspond to the output section. VIEW is a view into the
802 // output file holding the section contents, VIEW_ADDRESS is the
803 // virtual address of the view, and VIEW_SIZE is the size of the
804 // view. If NEEDS_SPECIAL_OFFSET_HANDLING is true, the VIEW_xx
805 // parameters refer to the complete output section data, not just
806 // the input section data.
808 relocate_section(const Relocate_info
<size
, big_endian
>*,
809 unsigned int sh_type
,
810 const unsigned char* prelocs
,
812 Output_section
* output_section
,
813 bool needs_special_offset_handling
,
815 typename
elfcpp::Elf_types
<size
>::Elf_Addr view_address
,
816 section_size_type view_size
,
817 const Reloc_symbol_changes
*) = 0;
819 // Scan the relocs during a relocatable link. The parameters are
820 // like scan_relocs, with an additional Relocatable_relocs
821 // parameter, used to record the disposition of the relocs.
823 scan_relocatable_relocs(Symbol_table
* symtab
,
825 Sized_relobj_file
<size
, big_endian
>* object
,
826 unsigned int data_shndx
,
827 unsigned int sh_type
,
828 const unsigned char* prelocs
,
830 Output_section
* output_section
,
831 bool needs_special_offset_handling
,
832 size_t local_symbol_count
,
833 const unsigned char* plocal_symbols
,
834 Relocatable_relocs
*) = 0;
836 // Emit relocations for a section during a relocatable link, and for
837 // --emit-relocs. The parameters are like relocate_section, with
838 // additional parameters for the view of the output reloc section.
840 relocate_relocs(const Relocate_info
<size
, big_endian
>*,
841 unsigned int sh_type
,
842 const unsigned char* prelocs
,
844 Output_section
* output_section
,
845 off_t offset_in_output_section
,
846 const Relocatable_relocs
*,
848 typename
elfcpp::Elf_types
<size
>::Elf_Addr view_address
,
849 section_size_type view_size
,
850 unsigned char* reloc_view
,
851 section_size_type reloc_view_size
) = 0;
853 // Perform target-specific processing in a relocatable link. This is
854 // only used if we use the relocation strategy RELOC_SPECIAL.
855 // RELINFO points to a Relocation_info structure. SH_TYPE is the relocation
856 // section type. PRELOC_IN points to the original relocation. RELNUM is
857 // the index number of the relocation in the relocation section.
858 // OUTPUT_SECTION is the output section to which the relocation is applied.
859 // OFFSET_IN_OUTPUT_SECTION is the offset of the relocation input section
860 // within the output section. VIEW points to the output view of the
861 // output section. VIEW_ADDRESS is output address of the view. VIEW_SIZE
862 // is the size of the output view and PRELOC_OUT points to the new
863 // relocation in the output object.
865 // A target only needs to override this if the generic code in
866 // target-reloc.h cannot handle some relocation types.
869 relocate_special_relocatable(const Relocate_info
<size
, big_endian
>*
871 unsigned int /* sh_type */,
872 const unsigned char* /* preloc_in */,
874 Output_section
* /* output_section */,
875 off_t
/* offset_in_output_section */,
876 unsigned char* /* view */,
877 typename
elfcpp::Elf_types
<size
>::Elf_Addr
879 section_size_type
/* view_size */,
880 unsigned char* /* preloc_out*/)
881 { gold_unreachable(); }
883 // Return the number of entries in the GOT. This is only used for
884 // laying out the incremental link info sections. A target needs
885 // to implement this to support incremental linking.
888 got_entry_count() const
889 { gold_unreachable(); }
891 // Return the number of entries in the PLT. This is only used for
892 // laying out the incremental link info sections. A target needs
893 // to implement this to support incremental linking.
896 plt_entry_count() const
897 { gold_unreachable(); }
899 // Return the offset of the first non-reserved PLT entry. This is
900 // only used for laying out the incremental link info sections.
901 // A target needs to implement this to support incremental linking.
904 first_plt_entry_offset() const
905 { gold_unreachable(); }
907 // Return the size of each PLT entry. This is only used for
908 // laying out the incremental link info sections. A target needs
909 // to implement this to support incremental linking.
912 plt_entry_size() const
913 { gold_unreachable(); }
915 // Create the GOT and PLT sections for an incremental update.
916 // A target needs to implement this to support incremental linking.
918 virtual Output_data_got_base
*
919 init_got_plt_for_update(Symbol_table
*,
921 unsigned int /* got_count */,
922 unsigned int /* plt_count */)
923 { gold_unreachable(); }
925 // Reserve a GOT entry for a local symbol, and regenerate any
926 // necessary dynamic relocations.
928 reserve_local_got_entry(unsigned int /* got_index */,
929 Sized_relobj
<size
, big_endian
>* /* obj */,
930 unsigned int /* r_sym */,
931 unsigned int /* got_type */)
932 { gold_unreachable(); }
934 // Reserve a GOT entry for a global symbol, and regenerate any
935 // necessary dynamic relocations.
937 reserve_global_got_entry(unsigned int /* got_index */, Symbol
* /* gsym */,
938 unsigned int /* got_type */)
939 { gold_unreachable(); }
941 // Register an existing PLT entry for a global symbol.
942 // A target needs to implement this to support incremental linking.
945 register_global_plt_entry(Symbol_table
*, Layout
*,
946 unsigned int /* plt_index */,
948 { gold_unreachable(); }
950 // Force a COPY relocation for a given symbol.
951 // A target needs to implement this to support incremental linking.
954 emit_copy_reloc(Symbol_table
*, Symbol
*, Output_section
*, off_t
)
955 { gold_unreachable(); }
957 // Apply an incremental relocation.
960 apply_relocation(const Relocate_info
<size
, big_endian
>* /* relinfo */,
961 typename
elfcpp::Elf_types
<size
>::Elf_Addr
/* r_offset */,
962 unsigned int /* r_type */,
963 typename
elfcpp::Elf_types
<size
>::Elf_Swxword
/* r_addend */,
964 const Symbol
* /* gsym */,
965 unsigned char* /* view */,
966 typename
elfcpp::Elf_types
<size
>::Elf_Addr
/* address */,
967 section_size_type
/* view_size */)
968 { gold_unreachable(); }
970 // Handle target specific gc actions when adding a gc reference from
971 // SRC_OBJ, SRC_SHNDX to a location specified by DST_OBJ, DST_SHNDX
974 gc_add_reference(Symbol_table
* symtab
,
976 unsigned int src_shndx
,
978 unsigned int dst_shndx
,
979 typename
elfcpp::Elf_types
<size
>::Elf_Addr dst_off
) const
981 this->do_gc_add_reference(symtab
, src_obj
, src_shndx
,
982 dst_obj
, dst_shndx
, dst_off
);
986 Sized_target(const Target::Target_info
* pti
)
989 gold_assert(pti
->size
== size
);
990 gold_assert(pti
->is_big_endian
? big_endian
: !big_endian
);
993 // Set the EI_OSABI field if requested.
995 do_adjust_elf_header(unsigned char*, int) const;
997 // Handle target specific gc actions when adding a gc reference.
999 do_gc_add_reference(Symbol_table
*, Object
*, unsigned int,
1000 Object
*, unsigned int,
1001 typename
elfcpp::Elf_types
<size
>::Elf_Addr
) const
1005 } // End namespace gold.
1007 #endif // !defined(GOLD_TARGET_H)