1 // arm.cc -- arm target support for gold.
3 // Copyright 2009 Free Software Foundation, Inc.
4 // Written by Doug Kwan <dougkwan@google.com> based on the i386 code
5 // 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.
32 #include "parameters.h"
39 #include "copy-relocs.h"
41 #include "target-reloc.h"
42 #include "target-select.h"
51 template<bool big_endian
>
52 class Output_data_plt_arm
;
54 // The arm target class.
56 // This is a very simple port of gold for ARM-EABI. It is intended for
57 // supporting Android only for the time being. Only these relocation types
77 // Coming soon (pending patches):
79 // - Defining section symbols __exidx_start and __exidx_stop.
80 // - Support interworking.
81 // - Mergeing all .ARM.xxx.yyy sections into .ARM.xxx. Currently, they
82 // are incorrectly merged into an .ARM section.
85 // - Create a PT_ARM_EXIDX program header for a shared object that
86 // might throw an exception.
87 // - Support more relocation types as needed.
88 // - Make PLTs more flexible for different architecture features like
91 template<bool big_endian
>
92 class Target_arm
: public Sized_target
<32, big_endian
>
95 typedef Output_data_reloc
<elfcpp::SHT_REL
, true, 32, big_endian
>
99 : Sized_target
<32, big_endian
>(&arm_info
),
100 got_(NULL
), plt_(NULL
), got_plt_(NULL
), rel_dyn_(NULL
),
101 copy_relocs_(elfcpp::R_ARM_COPY
), dynbss_(NULL
)
104 // Process the relocations to determine unreferenced sections for
105 // garbage collection.
107 gc_process_relocs(const General_options
& options
,
108 Symbol_table
* symtab
,
110 Sized_relobj
<32, big_endian
>* object
,
111 unsigned int data_shndx
,
112 unsigned int sh_type
,
113 const unsigned char* prelocs
,
115 Output_section
* output_section
,
116 bool needs_special_offset_handling
,
117 size_t local_symbol_count
,
118 const unsigned char* plocal_symbols
);
120 // Scan the relocations to look for symbol adjustments.
122 scan_relocs(const General_options
& options
,
123 Symbol_table
* symtab
,
125 Sized_relobj
<32, big_endian
>* object
,
126 unsigned int data_shndx
,
127 unsigned int sh_type
,
128 const unsigned char* prelocs
,
130 Output_section
* output_section
,
131 bool needs_special_offset_handling
,
132 size_t local_symbol_count
,
133 const unsigned char* plocal_symbols
);
135 // Finalize the sections.
137 do_finalize_sections(Layout
*);
139 // Return the value to use for a dynamic symbol which requires special
142 do_dynsym_value(const Symbol
*) const;
144 // Relocate a section.
146 relocate_section(const Relocate_info
<32, big_endian
>*,
147 unsigned int sh_type
,
148 const unsigned char* prelocs
,
150 Output_section
* output_section
,
151 bool needs_special_offset_handling
,
153 elfcpp::Elf_types
<32>::Elf_Addr view_address
,
154 section_size_type view_size
);
156 // Scan the relocs during a relocatable link.
158 scan_relocatable_relocs(const General_options
& options
,
159 Symbol_table
* symtab
,
161 Sized_relobj
<32, big_endian
>* object
,
162 unsigned int data_shndx
,
163 unsigned int sh_type
,
164 const unsigned char* prelocs
,
166 Output_section
* output_section
,
167 bool needs_special_offset_handling
,
168 size_t local_symbol_count
,
169 const unsigned char* plocal_symbols
,
170 Relocatable_relocs
*);
172 // Relocate a section during a relocatable link.
174 relocate_for_relocatable(const Relocate_info
<32, big_endian
>*,
175 unsigned int sh_type
,
176 const unsigned char* prelocs
,
178 Output_section
* output_section
,
179 off_t offset_in_output_section
,
180 const Relocatable_relocs
*,
182 elfcpp::Elf_types
<32>::Elf_Addr view_address
,
183 section_size_type view_size
,
184 unsigned char* reloc_view
,
185 section_size_type reloc_view_size
);
187 // Return whether SYM is defined by the ABI.
189 do_is_defined_by_abi(Symbol
* sym
) const
190 { return strcmp(sym
->name(), "__tls_get_addr") == 0; }
192 // Return the size of the GOT section.
196 gold_assert(this->got_
!= NULL
);
197 return this->got_
->data_size();
200 // Map platform-specific reloc types
202 get_real_reloc_type (unsigned int r_type
);
205 // The class which scans relocations.
210 : issued_non_pic_error_(false)
214 local(const General_options
& options
, Symbol_table
* symtab
,
215 Layout
* layout
, Target_arm
* target
,
216 Sized_relobj
<32, big_endian
>* object
,
217 unsigned int data_shndx
,
218 Output_section
* output_section
,
219 const elfcpp::Rel
<32, big_endian
>& reloc
, unsigned int r_type
,
220 const elfcpp::Sym
<32, big_endian
>& lsym
);
223 global(const General_options
& options
, Symbol_table
* symtab
,
224 Layout
* layout
, Target_arm
* target
,
225 Sized_relobj
<32, big_endian
>* object
,
226 unsigned int data_shndx
,
227 Output_section
* output_section
,
228 const elfcpp::Rel
<32, big_endian
>& reloc
, unsigned int r_type
,
233 unsupported_reloc_local(Sized_relobj
<32, big_endian
>*,
234 unsigned int r_type
);
237 unsupported_reloc_global(Sized_relobj
<32, big_endian
>*,
238 unsigned int r_type
, Symbol
*);
241 check_non_pic(Relobj
*, unsigned int r_type
);
243 // Almost identical to Symbol::needs_plt_entry except that it also
244 // handles STT_ARM_TFUNC.
246 symbol_needs_plt_entry(const Symbol
* sym
)
248 // An undefined symbol from an executable does not need a PLT entry.
249 if (sym
->is_undefined() && !parameters
->options().shared())
252 return (!parameters
->doing_static_link()
253 && (sym
->type() == elfcpp::STT_FUNC
254 || sym
->type() == elfcpp::STT_ARM_TFUNC
)
255 && (sym
->is_from_dynobj()
256 || sym
->is_undefined()
257 || sym
->is_preemptible()));
260 // Whether we have issued an error about a non-PIC compilation.
261 bool issued_non_pic_error_
;
264 // The class which implements relocation.
274 // Return whether the static relocation needs to be applied.
276 should_apply_static_reloc(const Sized_symbol
<32>* gsym
,
279 Output_section
* output_section
);
281 // Do a relocation. Return false if the caller should not issue
282 // any warnings about this relocation.
284 relocate(const Relocate_info
<32, big_endian
>*, Target_arm
*,
285 Output_section
*, size_t relnum
,
286 const elfcpp::Rel
<32, big_endian
>&,
287 unsigned int r_type
, const Sized_symbol
<32>*,
288 const Symbol_value
<32>*,
289 unsigned char*, elfcpp::Elf_types
<32>::Elf_Addr
,
293 // A class which returns the size required for a relocation type,
294 // used while scanning relocs during a relocatable link.
295 class Relocatable_size_for_reloc
299 get_size_for_reloc(unsigned int, Relobj
*);
302 // Get the GOT section, creating it if necessary.
303 Output_data_got
<32, big_endian
>*
304 got_section(Symbol_table
*, Layout
*);
306 // Get the GOT PLT section.
308 got_plt_section() const
310 gold_assert(this->got_plt_
!= NULL
);
311 return this->got_plt_
;
314 // Create a PLT entry for a global symbol.
316 make_plt_entry(Symbol_table
*, Layout
*, Symbol
*);
318 // Get the PLT section.
319 const Output_data_plt_arm
<big_endian
>*
322 gold_assert(this->plt_
!= NULL
);
326 // Get the dynamic reloc section, creating it if necessary.
328 rel_dyn_section(Layout
*);
330 // Return true if the symbol may need a COPY relocation.
331 // References from an executable object to non-function symbols
332 // defined in a dynamic object may need a COPY relocation.
334 may_need_copy_reloc(Symbol
* gsym
)
336 return (!parameters
->options().shared()
337 && gsym
->is_from_dynobj()
338 && gsym
->type() != elfcpp::STT_FUNC
339 && gsym
->type() != elfcpp::STT_ARM_TFUNC
);
342 // Add a potential copy relocation.
344 copy_reloc(Symbol_table
* symtab
, Layout
* layout
,
345 Sized_relobj
<32, big_endian
>* object
,
346 unsigned int shndx
, Output_section
* output_section
,
347 Symbol
* sym
, const elfcpp::Rel
<32, big_endian
>& reloc
)
349 this->copy_relocs_
.copy_reloc(symtab
, layout
,
350 symtab
->get_sized_symbol
<32>(sym
),
351 object
, shndx
, output_section
, reloc
,
352 this->rel_dyn_section(layout
));
355 // Information about this specific target which we pass to the
356 // general Target structure.
357 static const Target::Target_info arm_info
;
359 // The types of GOT entries needed for this platform.
362 GOT_TYPE_STANDARD
= 0 // GOT entry for a regular symbol
366 Output_data_got
<32, big_endian
>* got_
;
368 Output_data_plt_arm
<big_endian
>* plt_
;
369 // The GOT PLT section.
370 Output_data_space
* got_plt_
;
371 // The dynamic reloc section.
372 Reloc_section
* rel_dyn_
;
373 // Relocs saved to avoid a COPY reloc.
374 Copy_relocs
<elfcpp::SHT_REL
, 32, big_endian
> copy_relocs_
;
375 // Space for variables copied with a COPY reloc.
376 Output_data_space
* dynbss_
;
379 template<bool big_endian
>
380 const Target::Target_info Target_arm
<big_endian
>::arm_info
=
383 big_endian
, // is_big_endian
384 elfcpp::EM_ARM
, // machine_code
385 false, // has_make_symbol
386 false, // has_resolve
387 false, // has_code_fill
388 true, // is_default_stack_executable
390 "/usr/lib/libc.so.1", // dynamic_linker
391 0x8000, // default_text_segment_address
392 0x1000, // abi_pagesize (overridable by -z max-page-size)
393 0x1000 // common_pagesize (overridable by -z common-page-size)
396 // Get the GOT section, creating it if necessary.
398 template<bool big_endian
>
399 Output_data_got
<32, big_endian
>*
400 Target_arm
<big_endian
>::got_section(Symbol_table
* symtab
, Layout
* layout
)
402 if (this->got_
== NULL
)
404 gold_assert(symtab
!= NULL
&& layout
!= NULL
);
406 this->got_
= new Output_data_got
<32, big_endian
>();
409 os
= layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
411 | elfcpp::SHF_WRITE
),
415 // The old GNU linker creates a .got.plt section. We just
416 // create another set of data in the .got section. Note that we
417 // always create a PLT if we create a GOT, although the PLT
419 this->got_plt_
= new Output_data_space(4, "** GOT PLT");
420 os
= layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
422 | elfcpp::SHF_WRITE
),
426 // The first three entries are reserved.
427 this->got_plt_
->set_current_data_size(3 * 4);
429 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
430 symtab
->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL
,
432 0, 0, elfcpp::STT_OBJECT
,
434 elfcpp::STV_HIDDEN
, 0,
440 // Get the dynamic reloc section, creating it if necessary.
442 template<bool big_endian
>
443 typename Target_arm
<big_endian
>::Reloc_section
*
444 Target_arm
<big_endian
>::rel_dyn_section(Layout
* layout
)
446 if (this->rel_dyn_
== NULL
)
448 gold_assert(layout
!= NULL
);
449 this->rel_dyn_
= new Reloc_section(parameters
->options().combreloc());
450 layout
->add_output_section_data(".rel.dyn", elfcpp::SHT_REL
,
451 elfcpp::SHF_ALLOC
, this->rel_dyn_
);
453 return this->rel_dyn_
;
456 // A class to handle the PLT data.
458 template<bool big_endian
>
459 class Output_data_plt_arm
: public Output_section_data
462 typedef Output_data_reloc
<elfcpp::SHT_REL
, true, 32, big_endian
>
465 Output_data_plt_arm(Layout
*, Output_data_space
*);
467 // Add an entry to the PLT.
469 add_entry(Symbol
* gsym
);
471 // Return the .rel.plt section data.
474 { return this->rel_
; }
478 do_adjust_output_section(Output_section
* os
);
480 // Write to a map file.
482 do_print_to_mapfile(Mapfile
* mapfile
) const
483 { mapfile
->print_output_data(this, _("** PLT")); }
486 // Template for the first PLT entry.
487 static const uint32_t first_plt_entry
[5];
489 // Template for subsequent PLT entries.
490 static const uint32_t plt_entry
[3];
492 // Set the final size.
494 set_final_data_size()
496 this->set_data_size(sizeof(first_plt_entry
)
497 + this->count_
* sizeof(plt_entry
));
500 // Write out the PLT data.
502 do_write(Output_file
*);
504 // The reloc section.
506 // The .got.plt section.
507 Output_data_space
* got_plt_
;
508 // The number of PLT entries.
512 // Create the PLT section. The ordinary .got section is an argument,
513 // since we need to refer to the start. We also create our own .got
514 // section just for PLT entries.
516 template<bool big_endian
>
517 Output_data_plt_arm
<big_endian
>::Output_data_plt_arm(Layout
* layout
,
518 Output_data_space
* got_plt
)
519 : Output_section_data(4), got_plt_(got_plt
), count_(0)
521 this->rel_
= new Reloc_section(false);
522 layout
->add_output_section_data(".rel.plt", elfcpp::SHT_REL
,
523 elfcpp::SHF_ALLOC
, this->rel_
);
526 template<bool big_endian
>
528 Output_data_plt_arm
<big_endian
>::do_adjust_output_section(Output_section
* os
)
533 // Add an entry to the PLT.
535 template<bool big_endian
>
537 Output_data_plt_arm
<big_endian
>::add_entry(Symbol
* gsym
)
539 gold_assert(!gsym
->has_plt_offset());
541 // Note that when setting the PLT offset we skip the initial
542 // reserved PLT entry.
543 gsym
->set_plt_offset((this->count_
) * sizeof(plt_entry
)
544 + sizeof(first_plt_entry
));
548 section_offset_type got_offset
= this->got_plt_
->current_data_size();
550 // Every PLT entry needs a GOT entry which points back to the PLT
551 // entry (this will be changed by the dynamic linker, normally
552 // lazily when the function is called).
553 this->got_plt_
->set_current_data_size(got_offset
+ 4);
555 // Every PLT entry needs a reloc.
556 gsym
->set_needs_dynsym_entry();
557 this->rel_
->add_global(gsym
, elfcpp::R_ARM_JUMP_SLOT
, this->got_plt_
,
560 // Note that we don't need to save the symbol. The contents of the
561 // PLT are independent of which symbols are used. The symbols only
562 // appear in the relocations.
566 // FIXME: This is not very flexible. Right now this has only been tested
567 // on armv5te. If we are to support additional architecture features like
568 // Thumb-2 or BE8, we need to make this more flexible like GNU ld.
570 // The first entry in the PLT.
571 template<bool big_endian
>
572 const uint32_t Output_data_plt_arm
<big_endian
>::first_plt_entry
[5] =
574 0xe52de004, // str lr, [sp, #-4]!
575 0xe59fe004, // ldr lr, [pc, #4]
576 0xe08fe00e, // add lr, pc, lr
577 0xe5bef008, // ldr pc, [lr, #8]!
578 0x00000000, // &GOT[0] - .
581 // Subsequent entries in the PLT.
583 template<bool big_endian
>
584 const uint32_t Output_data_plt_arm
<big_endian
>::plt_entry
[3] =
586 0xe28fc600, // add ip, pc, #0xNN00000
587 0xe28cca00, // add ip, ip, #0xNN000
588 0xe5bcf000, // ldr pc, [ip, #0xNNN]!
591 // Write out the PLT. This uses the hand-coded instructions above,
592 // and adjusts them as needed. This is all specified by the arm ELF
593 // Processor Supplement.
595 template<bool big_endian
>
597 Output_data_plt_arm
<big_endian
>::do_write(Output_file
* of
)
599 const off_t offset
= this->offset();
600 const section_size_type oview_size
=
601 convert_to_section_size_type(this->data_size());
602 unsigned char* const oview
= of
->get_output_view(offset
, oview_size
);
604 const off_t got_file_offset
= this->got_plt_
->offset();
605 const section_size_type got_size
=
606 convert_to_section_size_type(this->got_plt_
->data_size());
607 unsigned char* const got_view
= of
->get_output_view(got_file_offset
,
609 unsigned char* pov
= oview
;
611 elfcpp::Elf_types
<32>::Elf_Addr plt_address
= this->address();
612 elfcpp::Elf_types
<32>::Elf_Addr got_address
= this->got_plt_
->address();
614 // Write first PLT entry. All but the last word are constants.
615 const size_t num_first_plt_words
= (sizeof(first_plt_entry
)
616 / sizeof(plt_entry
[0]));
617 for (size_t i
= 0; i
< num_first_plt_words
- 1; i
++)
618 elfcpp::Swap
<32, big_endian
>::writeval(pov
+ i
* 4, first_plt_entry
[i
]);
619 // Last word in first PLT entry is &GOT[0] - .
620 elfcpp::Swap
<32, big_endian
>::writeval(pov
+ 16,
621 got_address
- (plt_address
+ 16));
622 pov
+= sizeof(first_plt_entry
);
624 unsigned char* got_pov
= got_view
;
626 memset(got_pov
, 0, 12);
629 const int rel_size
= elfcpp::Elf_sizes
<32>::rel_size
;
630 unsigned int plt_offset
= sizeof(first_plt_entry
);
631 unsigned int plt_rel_offset
= 0;
632 unsigned int got_offset
= 12;
633 const unsigned int count
= this->count_
;
634 for (unsigned int i
= 0;
637 pov
+= sizeof(plt_entry
),
639 plt_offset
+= sizeof(plt_entry
),
640 plt_rel_offset
+= rel_size
,
643 // Set and adjust the PLT entry itself.
644 int32_t offset
= ((got_address
+ got_offset
)
645 - (plt_address
+ plt_offset
+ 8));
647 gold_assert(offset
>= 0 && offset
< 0x0fffffff);
648 uint32_t plt_insn0
= plt_entry
[0] | ((offset
>> 20) & 0xff);
649 elfcpp::Swap
<32, big_endian
>::writeval(pov
, plt_insn0
);
650 uint32_t plt_insn1
= plt_entry
[1] | ((offset
>> 12) & 0xff);
651 elfcpp::Swap
<32, big_endian
>::writeval(pov
+ 4, plt_insn1
);
652 uint32_t plt_insn2
= plt_entry
[2] | (offset
& 0xfff);
653 elfcpp::Swap
<32, big_endian
>::writeval(pov
+ 8, plt_insn2
);
655 // Set the entry in the GOT.
656 elfcpp::Swap
<32, big_endian
>::writeval(got_pov
, plt_address
);
659 gold_assert(static_cast<section_size_type
>(pov
- oview
) == oview_size
);
660 gold_assert(static_cast<section_size_type
>(got_pov
- got_view
) == got_size
);
662 of
->write_output_view(offset
, oview_size
, oview
);
663 of
->write_output_view(got_file_offset
, got_size
, got_view
);
666 // Create a PLT entry for a global symbol.
668 template<bool big_endian
>
670 Target_arm
<big_endian
>::make_plt_entry(Symbol_table
* symtab
, Layout
* layout
,
673 if (gsym
->has_plt_offset())
676 if (this->plt_
== NULL
)
678 // Create the GOT sections first.
679 this->got_section(symtab
, layout
);
681 this->plt_
= new Output_data_plt_arm
<big_endian
>(layout
, this->got_plt_
);
682 layout
->add_output_section_data(".plt", elfcpp::SHT_PROGBITS
,
684 | elfcpp::SHF_EXECINSTR
),
687 this->plt_
->add_entry(gsym
);
690 // Report an unsupported relocation against a local symbol.
692 template<bool big_endian
>
694 Target_arm
<big_endian
>::Scan::unsupported_reloc_local(
695 Sized_relobj
<32, big_endian
>* object
,
698 gold_error(_("%s: unsupported reloc %u against local symbol"),
699 object
->name().c_str(), r_type
);
702 // We are about to emit a dynamic relocation of type R_TYPE. If the
703 // dynamic linker does not support it, issue an error. The GNU linker
704 // only issues a non-PIC error for an allocated read-only section.
705 // Here we know the section is allocated, but we don't know that it is
706 // read-only. But we check for all the relocation types which the
707 // glibc dynamic linker supports, so it seems appropriate to issue an
708 // error even if the section is not read-only.
710 template<bool big_endian
>
712 Target_arm
<big_endian
>::Scan::check_non_pic(Relobj
* object
,
717 // These are the relocation types supported by glibc for ARM.
718 case elfcpp::R_ARM_RELATIVE
:
719 case elfcpp::R_ARM_COPY
:
720 case elfcpp::R_ARM_GLOB_DAT
:
721 case elfcpp::R_ARM_JUMP_SLOT
:
722 case elfcpp::R_ARM_ABS32
:
723 case elfcpp::R_ARM_PC24
:
724 // FIXME: The following 3 types are not supported by Android's dynamic
726 case elfcpp::R_ARM_TLS_DTPMOD32
:
727 case elfcpp::R_ARM_TLS_DTPOFF32
:
728 case elfcpp::R_ARM_TLS_TPOFF32
:
732 // This prevents us from issuing more than one error per reloc
733 // section. But we can still wind up issuing more than one
734 // error per object file.
735 if (this->issued_non_pic_error_
)
737 object
->error(_("requires unsupported dynamic reloc; "
738 "recompile with -fPIC"));
739 this->issued_non_pic_error_
= true;
742 case elfcpp::R_ARM_NONE
:
747 // Scan a relocation for a local symbol.
748 // FIXME: This only handles a subset of relocation types used by Android
749 // on ARM v5te devices.
751 template<bool big_endian
>
753 Target_arm
<big_endian
>::Scan::local(const General_options
&,
754 Symbol_table
* symtab
,
757 Sized_relobj
<32, big_endian
>* object
,
758 unsigned int data_shndx
,
759 Output_section
* output_section
,
760 const elfcpp::Rel
<32, big_endian
>& reloc
,
762 const elfcpp::Sym
<32, big_endian
>&)
764 r_type
= get_real_reloc_type(r_type
);
767 case elfcpp::R_ARM_NONE
:
770 case elfcpp::R_ARM_ABS32
:
771 // If building a shared library (or a position-independent
772 // executable), we need to create a dynamic relocation for
773 // this location. The relocation applied at link time will
774 // apply the link-time value, so we flag the location with
775 // an R_ARM_RELATIVE relocation so the dynamic loader can
776 // relocate it easily.
777 if (parameters
->options().output_is_position_independent())
779 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
780 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(reloc
.get_r_info());
781 // If we are to add more other reloc types than R_ARM_ABS32,
782 // we need to add check_non_pic(object, r_type) here.
783 rel_dyn
->add_local_relative(object
, r_sym
, elfcpp::R_ARM_RELATIVE
,
784 output_section
, data_shndx
,
785 reloc
.get_r_offset());
789 case elfcpp::R_ARM_REL32
:
790 case elfcpp::R_ARM_THM_CALL
:
791 case elfcpp::R_ARM_CALL
:
792 case elfcpp::R_ARM_PREL31
:
793 case elfcpp::R_ARM_JUMP24
:
794 case elfcpp::R_ARM_PLT32
:
797 case elfcpp::R_ARM_GOTOFF32
:
798 // We need a GOT section:
799 target
->got_section(symtab
, layout
);
802 case elfcpp::R_ARM_BASE_PREL
:
803 // FIXME: What about this?
806 case elfcpp::R_ARM_GOT_BREL
:
808 // The symbol requires a GOT entry.
809 Output_data_got
<32, big_endian
>* got
=
810 target
->got_section(symtab
, layout
);
811 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(reloc
.get_r_info());
812 if (got
->add_local(object
, r_sym
, GOT_TYPE_STANDARD
))
814 // If we are generating a shared object, we need to add a
815 // dynamic RELATIVE relocation for this symbol's GOT entry.
816 if (parameters
->options().output_is_position_independent())
818 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
819 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(reloc
.get_r_info());
820 rel_dyn
->add_local_relative(
821 object
, r_sym
, elfcpp::R_ARM_RELATIVE
, got
,
822 object
->local_got_offset(r_sym
, GOT_TYPE_STANDARD
));
828 case elfcpp::R_ARM_TARGET1
:
829 // This should have been mapped to another type already.
831 case elfcpp::R_ARM_COPY
:
832 case elfcpp::R_ARM_GLOB_DAT
:
833 case elfcpp::R_ARM_JUMP_SLOT
:
834 case elfcpp::R_ARM_RELATIVE
:
835 // These are relocations which should only be seen by the
836 // dynamic linker, and should never be seen here.
837 gold_error(_("%s: unexpected reloc %u in object file"),
838 object
->name().c_str(), r_type
);
842 unsupported_reloc_local(object
, r_type
);
847 // Report an unsupported relocation against a global symbol.
849 template<bool big_endian
>
851 Target_arm
<big_endian
>::Scan::unsupported_reloc_global(
852 Sized_relobj
<32, big_endian
>* object
,
856 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
857 object
->name().c_str(), r_type
, gsym
->demangled_name().c_str());
860 // Scan a relocation for a global symbol.
861 // FIXME: This only handles a subset of relocation types used by Android
862 // on ARM v5te devices.
864 template<bool big_endian
>
866 Target_arm
<big_endian
>::Scan::global(const General_options
&,
867 Symbol_table
* symtab
,
870 Sized_relobj
<32, big_endian
>* object
,
871 unsigned int data_shndx
,
872 Output_section
* output_section
,
873 const elfcpp::Rel
<32, big_endian
>& reloc
,
877 r_type
= get_real_reloc_type(r_type
);
880 case elfcpp::R_ARM_NONE
:
883 case elfcpp::R_ARM_ABS32
:
885 // Make a dynamic relocation if necessary.
886 if (gsym
->needs_dynamic_reloc(Symbol::ABSOLUTE_REF
))
888 if (target
->may_need_copy_reloc(gsym
))
890 target
->copy_reloc(symtab
, layout
, object
,
891 data_shndx
, output_section
, gsym
, reloc
);
893 else if (gsym
->can_use_relative_reloc(false))
895 // If we are to add more other reloc types than R_ARM_ABS32,
896 // we need to add check_non_pic(object, r_type) here.
897 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
898 rel_dyn
->add_global_relative(gsym
, elfcpp::R_ARM_RELATIVE
,
899 output_section
, object
,
900 data_shndx
, reloc
.get_r_offset());
904 // If we are to add more other reloc types than R_ARM_ABS32,
905 // we need to add check_non_pic(object, r_type) here.
906 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
907 rel_dyn
->add_global(gsym
, r_type
, output_section
, object
,
908 data_shndx
, reloc
.get_r_offset());
914 case elfcpp::R_ARM_REL32
:
915 case elfcpp::R_ARM_PREL31
:
917 // Make a dynamic relocation if necessary.
918 int flags
= Symbol::NON_PIC_REF
;
919 if (gsym
->needs_dynamic_reloc(flags
))
921 if (target
->may_need_copy_reloc(gsym
))
923 target
->copy_reloc(symtab
, layout
, object
,
924 data_shndx
, output_section
, gsym
, reloc
);
928 check_non_pic(object
, r_type
);
929 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
930 rel_dyn
->add_global(gsym
, r_type
, output_section
, object
,
931 data_shndx
, reloc
.get_r_offset());
937 case elfcpp::R_ARM_JUMP24
:
938 case elfcpp::R_ARM_THM_CALL
:
939 case elfcpp::R_ARM_CALL
:
941 if (Target_arm
<big_endian
>::Scan::symbol_needs_plt_entry(gsym
))
942 target
->make_plt_entry(symtab
, layout
, gsym
);
943 // Make a dynamic relocation if necessary.
944 int flags
= Symbol::NON_PIC_REF
;
945 if (gsym
->type() == elfcpp::STT_FUNC
946 || gsym
->type() == elfcpp::STT_ARM_TFUNC
)
947 flags
|= Symbol::FUNCTION_CALL
;
948 if (gsym
->needs_dynamic_reloc(flags
))
950 if (target
->may_need_copy_reloc(gsym
))
952 target
->copy_reloc(symtab
, layout
, object
,
953 data_shndx
, output_section
, gsym
,
958 check_non_pic(object
, r_type
);
959 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
960 rel_dyn
->add_global(gsym
, r_type
, output_section
, object
,
961 data_shndx
, reloc
.get_r_offset());
967 case elfcpp::R_ARM_PLT32
:
968 // If the symbol is fully resolved, this is just a relative
969 // local reloc. Otherwise we need a PLT entry.
970 if (gsym
->final_value_is_known())
972 // If building a shared library, we can also skip the PLT entry
973 // if the symbol is defined in the output file and is protected
975 if (gsym
->is_defined()
976 && !gsym
->is_from_dynobj()
977 && !gsym
->is_preemptible())
979 target
->make_plt_entry(symtab
, layout
, gsym
);
982 case elfcpp::R_ARM_GOTOFF32
:
983 // We need a GOT section.
984 target
->got_section(symtab
, layout
);
987 case elfcpp::R_ARM_BASE_PREL
:
988 // FIXME: What about this?
991 case elfcpp::R_ARM_GOT_BREL
:
993 // The symbol requires a GOT entry.
994 Output_data_got
<32, big_endian
>* got
=
995 target
->got_section(symtab
, layout
);
996 if (gsym
->final_value_is_known())
997 got
->add_global(gsym
, GOT_TYPE_STANDARD
);
1000 // If this symbol is not fully resolved, we need to add a
1001 // GOT entry with a dynamic relocation.
1002 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1003 if (gsym
->is_from_dynobj()
1004 || gsym
->is_undefined()
1005 || gsym
->is_preemptible())
1006 got
->add_global_with_rel(gsym
, GOT_TYPE_STANDARD
,
1007 rel_dyn
, elfcpp::R_ARM_GLOB_DAT
);
1010 if (got
->add_global(gsym
, GOT_TYPE_STANDARD
))
1011 rel_dyn
->add_global_relative(
1012 gsym
, elfcpp::R_ARM_RELATIVE
, got
,
1013 gsym
->got_offset(GOT_TYPE_STANDARD
));
1019 case elfcpp::R_ARM_TARGET1
:
1020 // This should have been mapped to another type already.
1022 case elfcpp::R_ARM_COPY
:
1023 case elfcpp::R_ARM_GLOB_DAT
:
1024 case elfcpp::R_ARM_JUMP_SLOT
:
1025 case elfcpp::R_ARM_RELATIVE
:
1026 // These are relocations which should only be seen by the
1027 // dynamic linker, and should never be seen here.
1028 gold_error(_("%s: unexpected reloc %u in object file"),
1029 object
->name().c_str(), r_type
);
1033 unsupported_reloc_global(object
, r_type
, gsym
);
1038 // Process relocations for gc.
1040 template<bool big_endian
>
1042 Target_arm
<big_endian
>::gc_process_relocs(const General_options
& options
,
1043 Symbol_table
* symtab
,
1045 Sized_relobj
<32, big_endian
>* object
,
1046 unsigned int data_shndx
,
1048 const unsigned char* prelocs
,
1050 Output_section
* output_section
,
1051 bool needs_special_offset_handling
,
1052 size_t local_symbol_count
,
1053 const unsigned char* plocal_symbols
)
1055 typedef Target_arm
<big_endian
> Arm
;
1056 typedef typename Target_arm
<big_endian
>::Scan Scan
;
1058 gold::gc_process_relocs
<32, big_endian
, Arm
, elfcpp::SHT_REL
, Scan
>(
1068 needs_special_offset_handling
,
1073 // Scan relocations for a section.
1075 template<bool big_endian
>
1077 Target_arm
<big_endian
>::scan_relocs(const General_options
& options
,
1078 Symbol_table
* symtab
,
1080 Sized_relobj
<32, big_endian
>* object
,
1081 unsigned int data_shndx
,
1082 unsigned int sh_type
,
1083 const unsigned char* prelocs
,
1085 Output_section
* output_section
,
1086 bool needs_special_offset_handling
,
1087 size_t local_symbol_count
,
1088 const unsigned char* plocal_symbols
)
1090 typedef typename Target_arm
<big_endian
>::Scan Scan
;
1091 if (sh_type
== elfcpp::SHT_RELA
)
1093 gold_error(_("%s: unsupported RELA reloc section"),
1094 object
->name().c_str());
1098 gold::scan_relocs
<32, big_endian
, Target_arm
, elfcpp::SHT_REL
, Scan
>(
1108 needs_special_offset_handling
,
1113 // Finalize the sections.
1115 template<bool big_endian
>
1117 Target_arm
<big_endian
>::do_finalize_sections(Layout
* layout
)
1119 // Fill in some more dynamic tags.
1120 Output_data_dynamic
* const odyn
= layout
->dynamic_data();
1123 if (this->got_plt_
!= NULL
)
1124 odyn
->add_section_address(elfcpp::DT_PLTGOT
, this->got_plt_
);
1126 if (this->plt_
!= NULL
)
1128 const Output_data
* od
= this->plt_
->rel_plt();
1129 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, od
);
1130 odyn
->add_section_address(elfcpp::DT_JMPREL
, od
);
1131 odyn
->add_constant(elfcpp::DT_PLTREL
, elfcpp::DT_REL
);
1134 if (this->rel_dyn_
!= NULL
)
1136 const Output_data
* od
= this->rel_dyn_
;
1137 odyn
->add_section_address(elfcpp::DT_REL
, od
);
1138 odyn
->add_section_size(elfcpp::DT_RELSZ
, od
);
1139 odyn
->add_constant(elfcpp::DT_RELENT
,
1140 elfcpp::Elf_sizes
<32>::rel_size
);
1143 if (!parameters
->options().shared())
1145 // The value of the DT_DEBUG tag is filled in by the dynamic
1146 // linker at run time, and used by the debugger.
1147 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
1151 // Emit any relocs we saved in an attempt to avoid generating COPY
1153 if (this->copy_relocs_
.any_saved_relocs())
1154 this->copy_relocs_
.emit(this->rel_dyn_section(layout
));
1157 // Return whether a direct absolute static relocation needs to be applied.
1158 // In cases where Scan::local() or Scan::global() has created
1159 // a dynamic relocation other than R_ARM_RELATIVE, the addend
1160 // of the relocation is carried in the data, and we must not
1161 // apply the static relocation.
1163 template<bool big_endian
>
1165 Target_arm
<big_endian
>::Relocate::should_apply_static_reloc(
1166 const Sized_symbol
<32>* gsym
,
1169 Output_section
* output_section
)
1171 // If the output section is not allocated, then we didn't call
1172 // scan_relocs, we didn't create a dynamic reloc, and we must apply
1174 if ((output_section
->flags() & elfcpp::SHF_ALLOC
) == 0)
1177 // For local symbols, we will have created a non-RELATIVE dynamic
1178 // relocation only if (a) the output is position independent,
1179 // (b) the relocation is absolute (not pc- or segment-relative), and
1180 // (c) the relocation is not 32 bits wide.
1182 return !(parameters
->options().output_is_position_independent()
1183 && (ref_flags
& Symbol::ABSOLUTE_REF
)
1186 // For global symbols, we use the same helper routines used in the
1187 // scan pass. If we did not create a dynamic relocation, or if we
1188 // created a RELATIVE dynamic relocation, we should apply the static
1190 bool has_dyn
= gsym
->needs_dynamic_reloc(ref_flags
);
1191 bool is_rel
= (ref_flags
& Symbol::ABSOLUTE_REF
)
1192 && gsym
->can_use_relative_reloc(ref_flags
1193 & Symbol::FUNCTION_CALL
);
1194 return !has_dyn
|| is_rel
;
1197 // Perform a relocation.
1199 template<bool big_endian
>
1201 Target_arm
<big_endian
>::Relocate::relocate(
1202 const Relocate_info
<32, big_endian
>* /* relinfo */,
1203 Target_arm
* /* target */,
1204 Output_section
* /* output_section */,
1205 size_t /* relnum */,
1206 const elfcpp::Rel
<32, big_endian
>& /* rel */,
1207 unsigned int r_type
,
1208 const Sized_symbol
<32>* /* gsym */,
1209 const Symbol_value
<32>* /* psymval */,
1210 unsigned char* /* view */,
1211 elfcpp::Elf_types
<32>::Elf_Addr
/* address */,
1212 section_size_type
/* view_size */ )
1216 case elfcpp::R_ARM_NONE
:
1226 // Relocate section data.
1228 template<bool big_endian
>
1230 Target_arm
<big_endian
>::relocate_section(
1231 const Relocate_info
<32, big_endian
>* relinfo
,
1232 unsigned int sh_type
,
1233 const unsigned char* prelocs
,
1235 Output_section
* output_section
,
1236 bool needs_special_offset_handling
,
1237 unsigned char* view
,
1238 elfcpp::Elf_types
<32>::Elf_Addr address
,
1239 section_size_type view_size
)
1241 typedef typename Target_arm
<big_endian
>::Relocate Arm_relocate
;
1242 gold_assert(sh_type
== elfcpp::SHT_REL
);
1244 gold::relocate_section
<32, big_endian
, Target_arm
, elfcpp::SHT_REL
,
1251 needs_special_offset_handling
,
1257 // Return the size of a relocation while scanning during a relocatable
1260 template<bool big_endian
>
1262 Target_arm
<big_endian
>::Relocatable_size_for_reloc::get_size_for_reloc(
1263 unsigned int r_type
,
1266 r_type
= get_real_reloc_type(r_type
);
1269 case elfcpp::R_ARM_NONE
:
1272 case elfcpp::R_ARM_ABS32
:
1273 case elfcpp::R_ARM_REL32
:
1274 case elfcpp::R_ARM_THM_CALL
:
1275 case elfcpp::R_ARM_GOTOFF32
:
1276 case elfcpp::R_ARM_BASE_PREL
:
1277 case elfcpp::R_ARM_GOT_BREL
:
1278 case elfcpp::R_ARM_PLT32
:
1279 case elfcpp::R_ARM_CALL
:
1280 case elfcpp::R_ARM_JUMP24
:
1281 case elfcpp::R_ARM_PREL31
:
1284 case elfcpp::R_ARM_TARGET1
:
1285 // This should have been mapped to another type already.
1287 case elfcpp::R_ARM_COPY
:
1288 case elfcpp::R_ARM_GLOB_DAT
:
1289 case elfcpp::R_ARM_JUMP_SLOT
:
1290 case elfcpp::R_ARM_RELATIVE
:
1291 // These are relocations which should only be seen by the
1292 // dynamic linker, and should never be seen here.
1293 gold_error(_("%s: unexpected reloc %u in object file"),
1294 object
->name().c_str(), r_type
);
1298 object
->error(_("unsupported reloc %u in object file"), r_type
);
1303 // Scan the relocs during a relocatable link.
1305 template<bool big_endian
>
1307 Target_arm
<big_endian
>::scan_relocatable_relocs(
1308 const General_options
& options
,
1309 Symbol_table
* symtab
,
1311 Sized_relobj
<32, big_endian
>* object
,
1312 unsigned int data_shndx
,
1313 unsigned int sh_type
,
1314 const unsigned char* prelocs
,
1316 Output_section
* output_section
,
1317 bool needs_special_offset_handling
,
1318 size_t local_symbol_count
,
1319 const unsigned char* plocal_symbols
,
1320 Relocatable_relocs
* rr
)
1322 gold_assert(sh_type
== elfcpp::SHT_REL
);
1324 typedef gold::Default_scan_relocatable_relocs
<elfcpp::SHT_REL
,
1325 Relocatable_size_for_reloc
> Scan_relocatable_relocs
;
1327 gold::scan_relocatable_relocs
<32, big_endian
, elfcpp::SHT_REL
,
1328 Scan_relocatable_relocs
>(
1337 needs_special_offset_handling
,
1343 // Relocate a section during a relocatable link.
1345 template<bool big_endian
>
1347 Target_arm
<big_endian
>::relocate_for_relocatable(
1348 const Relocate_info
<32, big_endian
>* relinfo
,
1349 unsigned int sh_type
,
1350 const unsigned char* prelocs
,
1352 Output_section
* output_section
,
1353 off_t offset_in_output_section
,
1354 const Relocatable_relocs
* rr
,
1355 unsigned char* view
,
1356 elfcpp::Elf_types
<32>::Elf_Addr view_address
,
1357 section_size_type view_size
,
1358 unsigned char* reloc_view
,
1359 section_size_type reloc_view_size
)
1361 gold_assert(sh_type
== elfcpp::SHT_REL
);
1363 gold::relocate_for_relocatable
<32, big_endian
, elfcpp::SHT_REL
>(
1368 offset_in_output_section
,
1377 // Return the value to use for a dynamic symbol which requires special
1378 // treatment. This is how we support equality comparisons of function
1379 // pointers across shared library boundaries, as described in the
1380 // processor specific ABI supplement.
1382 template<bool big_endian
>
1384 Target_arm
<big_endian
>::do_dynsym_value(const Symbol
* gsym
) const
1386 gold_assert(gsym
->is_from_dynobj() && gsym
->has_plt_offset());
1387 return this->plt_section()->address() + gsym
->plt_offset();
1390 // Map platform-specific relocs to real relocs
1392 template<bool big_endian
>
1394 Target_arm
<big_endian
>::get_real_reloc_type (unsigned int r_type
)
1398 case elfcpp::R_ARM_TARGET1
:
1399 // This is either R_ARM_ABS32 or R_ARM_REL32;
1400 return elfcpp::R_ARM_ABS32
;
1402 case elfcpp::R_ARM_TARGET2
:
1403 // This can be any reloc type but ususally is R_ARM_GOT_PREL
1404 return elfcpp::R_ARM_GOT_PREL
;
1411 // The selector for arm object files.
1413 template<bool big_endian
>
1414 class Target_selector_arm
: public Target_selector
1417 Target_selector_arm()
1418 : Target_selector(elfcpp::EM_ARM
, 32, big_endian
,
1419 (big_endian
? "elf32-bigarm" : "elf32-littlearm"))
1423 do_instantiate_target()
1424 { return new Target_arm
<big_endian
>(); }
1427 Target_selector_arm
<false> target_selector_arm
;
1428 Target_selector_arm
<true> target_selector_armbe
;
1430 } // End anonymous namespace.