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
78 // - Generate various branch stubs.
79 // - Support interworking.
80 // - Define section symbols __exidx_start and __exidx_stop.
81 // - Support more relocation types as needed.
82 // - Make PLTs more flexible for different architecture features like
84 // There are probably a lot more.
86 // Utilities for manipulating integers of up to 32-bits
90 // Sign extend an n-bit unsigned integer stored in an uint32_t into
91 // an int32_t. NO_BITS must be between 1 to 32.
94 sign_extend(uint32_t bits
)
96 gold_assert(no_bits
>= 0 && no_bits
<= 32);
98 return static_cast<int32_t>(bits
);
99 uint32_t mask
= (~((uint32_t) 0)) >> (32 - no_bits
);
101 uint32_t top_bit
= 1U << (no_bits
- 1);
102 int32_t as_signed
= static_cast<int32_t>(bits
);
103 return (bits
& top_bit
) ? as_signed
+ (-top_bit
* 2) : as_signed
;
106 // Detects overflow of an NO_BITS integer stored in a uint32_t.
107 template<int no_bits
>
109 has_overflow(uint32_t bits
)
111 gold_assert(no_bits
>= 0 && no_bits
<= 32);
114 int32_t max
= (1 << (no_bits
- 1)) - 1;
115 int32_t min
= -(1 << (no_bits
- 1));
116 int32_t as_signed
= static_cast<int32_t>(bits
);
117 return as_signed
> max
|| as_signed
< min
;
120 // Detects overflow of an NO_BITS integer stored in a uint32_t when it
121 // fits in the given number of bits as either a signed or unsigned value.
122 // For example, has_signed_unsigned_overflow<8> would check
123 // -128 <= bits <= 255
124 template<int no_bits
>
126 has_signed_unsigned_overflow(uint32_t bits
)
128 gold_assert(no_bits
>= 2 && no_bits
<= 32);
131 int32_t max
= static_cast<int32_t>((1U << no_bits
) - 1);
132 int32_t min
= -(1 << (no_bits
- 1));
133 int32_t as_signed
= static_cast<int32_t>(bits
);
134 return as_signed
> max
|| as_signed
< min
;
137 // Select bits from A and B using bits in MASK. For each n in [0..31],
138 // the n-th bit in the result is chosen from the n-th bits of A and B.
139 // A zero selects A and a one selects B.
140 static inline uint32_t
141 bit_select(uint32_t a
, uint32_t b
, uint32_t mask
)
142 { return (a
& ~mask
) | (b
& mask
); }
145 template<bool big_endian
>
146 class Target_arm
: public Sized_target
<32, big_endian
>
149 typedef Output_data_reloc
<elfcpp::SHT_REL
, true, 32, big_endian
>
153 : Sized_target
<32, big_endian
>(&arm_info
),
154 got_(NULL
), plt_(NULL
), got_plt_(NULL
), rel_dyn_(NULL
),
155 copy_relocs_(elfcpp::R_ARM_COPY
), dynbss_(NULL
)
158 // Process the relocations to determine unreferenced sections for
159 // garbage collection.
161 gc_process_relocs(const General_options
& options
,
162 Symbol_table
* symtab
,
164 Sized_relobj
<32, big_endian
>* object
,
165 unsigned int data_shndx
,
166 unsigned int sh_type
,
167 const unsigned char* prelocs
,
169 Output_section
* output_section
,
170 bool needs_special_offset_handling
,
171 size_t local_symbol_count
,
172 const unsigned char* plocal_symbols
);
174 // Scan the relocations to look for symbol adjustments.
176 scan_relocs(const General_options
& options
,
177 Symbol_table
* symtab
,
179 Sized_relobj
<32, big_endian
>* object
,
180 unsigned int data_shndx
,
181 unsigned int sh_type
,
182 const unsigned char* prelocs
,
184 Output_section
* output_section
,
185 bool needs_special_offset_handling
,
186 size_t local_symbol_count
,
187 const unsigned char* plocal_symbols
);
189 // Finalize the sections.
191 do_finalize_sections(Layout
*);
193 // Return the value to use for a dynamic symbol which requires special
196 do_dynsym_value(const Symbol
*) const;
198 // Relocate a section.
200 relocate_section(const Relocate_info
<32, big_endian
>*,
201 unsigned int sh_type
,
202 const unsigned char* prelocs
,
204 Output_section
* output_section
,
205 bool needs_special_offset_handling
,
207 elfcpp::Elf_types
<32>::Elf_Addr view_address
,
208 section_size_type view_size
);
210 // Scan the relocs during a relocatable link.
212 scan_relocatable_relocs(const General_options
& options
,
213 Symbol_table
* symtab
,
215 Sized_relobj
<32, big_endian
>* object
,
216 unsigned int data_shndx
,
217 unsigned int sh_type
,
218 const unsigned char* prelocs
,
220 Output_section
* output_section
,
221 bool needs_special_offset_handling
,
222 size_t local_symbol_count
,
223 const unsigned char* plocal_symbols
,
224 Relocatable_relocs
*);
226 // Relocate a section during a relocatable link.
228 relocate_for_relocatable(const Relocate_info
<32, big_endian
>*,
229 unsigned int sh_type
,
230 const unsigned char* prelocs
,
232 Output_section
* output_section
,
233 off_t offset_in_output_section
,
234 const Relocatable_relocs
*,
236 elfcpp::Elf_types
<32>::Elf_Addr view_address
,
237 section_size_type view_size
,
238 unsigned char* reloc_view
,
239 section_size_type reloc_view_size
);
241 // Return whether SYM is defined by the ABI.
243 do_is_defined_by_abi(Symbol
* sym
) const
244 { return strcmp(sym
->name(), "__tls_get_addr") == 0; }
246 // Return the size of the GOT section.
250 gold_assert(this->got_
!= NULL
);
251 return this->got_
->data_size();
254 // Map platform-specific reloc types
256 get_real_reloc_type (unsigned int r_type
);
259 // The class which scans relocations.
264 : issued_non_pic_error_(false)
268 local(const General_options
& options
, Symbol_table
* symtab
,
269 Layout
* layout
, Target_arm
* target
,
270 Sized_relobj
<32, big_endian
>* object
,
271 unsigned int data_shndx
,
272 Output_section
* output_section
,
273 const elfcpp::Rel
<32, big_endian
>& reloc
, unsigned int r_type
,
274 const elfcpp::Sym
<32, big_endian
>& lsym
);
277 global(const General_options
& options
, Symbol_table
* symtab
,
278 Layout
* layout
, Target_arm
* target
,
279 Sized_relobj
<32, big_endian
>* object
,
280 unsigned int data_shndx
,
281 Output_section
* output_section
,
282 const elfcpp::Rel
<32, big_endian
>& reloc
, unsigned int r_type
,
287 unsupported_reloc_local(Sized_relobj
<32, big_endian
>*,
288 unsigned int r_type
);
291 unsupported_reloc_global(Sized_relobj
<32, big_endian
>*,
292 unsigned int r_type
, Symbol
*);
295 check_non_pic(Relobj
*, unsigned int r_type
);
297 // Almost identical to Symbol::needs_plt_entry except that it also
298 // handles STT_ARM_TFUNC.
300 symbol_needs_plt_entry(const Symbol
* sym
)
302 // An undefined symbol from an executable does not need a PLT entry.
303 if (sym
->is_undefined() && !parameters
->options().shared())
306 return (!parameters
->doing_static_link()
307 && (sym
->type() == elfcpp::STT_FUNC
308 || sym
->type() == elfcpp::STT_ARM_TFUNC
)
309 && (sym
->is_from_dynobj()
310 || sym
->is_undefined()
311 || sym
->is_preemptible()));
314 // Whether we have issued an error about a non-PIC compilation.
315 bool issued_non_pic_error_
;
318 // The class which implements relocation.
328 // Return whether the static relocation needs to be applied.
330 should_apply_static_reloc(const Sized_symbol
<32>* gsym
,
333 Output_section
* output_section
);
335 // Do a relocation. Return false if the caller should not issue
336 // any warnings about this relocation.
338 relocate(const Relocate_info
<32, big_endian
>*, Target_arm
*,
339 Output_section
*, size_t relnum
,
340 const elfcpp::Rel
<32, big_endian
>&,
341 unsigned int r_type
, const Sized_symbol
<32>*,
342 const Symbol_value
<32>*,
343 unsigned char*, elfcpp::Elf_types
<32>::Elf_Addr
,
346 // Return whether we want to pass flag NON_PIC_REF for this
349 reloc_is_non_pic (unsigned int r_type
)
353 case elfcpp::R_ARM_REL32
:
354 case elfcpp::R_ARM_THM_CALL
:
355 case elfcpp::R_ARM_CALL
:
356 case elfcpp::R_ARM_JUMP24
:
357 case elfcpp::R_ARM_PREL31
:
365 // A class which returns the size required for a relocation type,
366 // used while scanning relocs during a relocatable link.
367 class Relocatable_size_for_reloc
371 get_size_for_reloc(unsigned int, Relobj
*);
374 // Get the GOT section, creating it if necessary.
375 Output_data_got
<32, big_endian
>*
376 got_section(Symbol_table
*, Layout
*);
378 // Get the GOT PLT section.
380 got_plt_section() const
382 gold_assert(this->got_plt_
!= NULL
);
383 return this->got_plt_
;
386 // Create a PLT entry for a global symbol.
388 make_plt_entry(Symbol_table
*, Layout
*, Symbol
*);
390 // Get the PLT section.
391 const Output_data_plt_arm
<big_endian
>*
394 gold_assert(this->plt_
!= NULL
);
398 // Get the dynamic reloc section, creating it if necessary.
400 rel_dyn_section(Layout
*);
402 // Return true if the symbol may need a COPY relocation.
403 // References from an executable object to non-function symbols
404 // defined in a dynamic object may need a COPY relocation.
406 may_need_copy_reloc(Symbol
* gsym
)
408 return (!parameters
->options().shared()
409 && gsym
->is_from_dynobj()
410 && gsym
->type() != elfcpp::STT_FUNC
411 && gsym
->type() != elfcpp::STT_ARM_TFUNC
);
414 // Add a potential copy relocation.
416 copy_reloc(Symbol_table
* symtab
, Layout
* layout
,
417 Sized_relobj
<32, big_endian
>* object
,
418 unsigned int shndx
, Output_section
* output_section
,
419 Symbol
* sym
, const elfcpp::Rel
<32, big_endian
>& reloc
)
421 this->copy_relocs_
.copy_reloc(symtab
, layout
,
422 symtab
->get_sized_symbol
<32>(sym
),
423 object
, shndx
, output_section
, reloc
,
424 this->rel_dyn_section(layout
));
427 // Information about this specific target which we pass to the
428 // general Target structure.
429 static const Target::Target_info arm_info
;
431 // The types of GOT entries needed for this platform.
434 GOT_TYPE_STANDARD
= 0 // GOT entry for a regular symbol
438 Output_data_got
<32, big_endian
>* got_
;
440 Output_data_plt_arm
<big_endian
>* plt_
;
441 // The GOT PLT section.
442 Output_data_space
* got_plt_
;
443 // The dynamic reloc section.
444 Reloc_section
* rel_dyn_
;
445 // Relocs saved to avoid a COPY reloc.
446 Copy_relocs
<elfcpp::SHT_REL
, 32, big_endian
> copy_relocs_
;
447 // Space for variables copied with a COPY reloc.
448 Output_data_space
* dynbss_
;
451 template<bool big_endian
>
452 const Target::Target_info Target_arm
<big_endian
>::arm_info
=
455 big_endian
, // is_big_endian
456 elfcpp::EM_ARM
, // machine_code
457 false, // has_make_symbol
458 false, // has_resolve
459 false, // has_code_fill
460 true, // is_default_stack_executable
462 "/usr/lib/libc.so.1", // dynamic_linker
463 0x8000, // default_text_segment_address
464 0x1000, // abi_pagesize (overridable by -z max-page-size)
465 0x1000, // common_pagesize (overridable by -z common-page-size)
466 elfcpp::SHN_UNDEF
, // small_common_shndx
467 elfcpp::SHN_UNDEF
, // large_common_shndx
468 0, // small_common_section_flags
469 0 // large_common_section_flags
472 // Arm relocate functions class
475 template<bool big_endian
>
476 class Arm_relocate_functions
: public Relocate_functions
<32, big_endian
>
481 STATUS_OKAY
, // No error during relocation.
482 STATUS_OVERFLOW
, // Relocation oveflow.
483 STATUS_BAD_RELOC
// Relocation cannot be applied.
487 typedef Relocate_functions
<32, big_endian
> Base
;
488 typedef Arm_relocate_functions
<big_endian
> This
;
490 // Get an symbol value of *PSYMVAL with an ADDEND. This is a wrapper
491 // to Symbol_value::value(). If HAS_THUMB_BIT is true, that LSB is used
492 // to distinguish ARM and THUMB functions and it is treated specially.
493 static inline Symbol_value
<32>::Value
494 arm_symbol_value (const Sized_relobj
<32, big_endian
> *object
,
495 const Symbol_value
<32>* psymval
,
496 Symbol_value
<32>::Value addend
,
499 typedef Symbol_value
<32>::Value Valtype
;
503 Valtype raw
= psymval
->value(object
, 0);
504 Valtype thumb_bit
= raw
& 1;
505 return ((raw
& ~((Valtype
) 1)) + addend
) | thumb_bit
;
508 return psymval
->value(object
, addend
);
511 // FIXME: This probably only works for Android on ARM v5te. We should
512 // following GNU ld for the general case.
513 template<unsigned r_type
>
514 static inline typename
This::Status
515 arm_branch_common(unsigned char *view
,
516 const Sized_relobj
<32, big_endian
>* object
,
517 const Symbol_value
<32>* psymval
,
518 elfcpp::Elf_types
<32>::Elf_Addr address
,
521 typedef typename
elfcpp::Swap
<32, big_endian
>::Valtype Valtype
;
522 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
523 Valtype val
= elfcpp::Swap
<32, big_endian
>::readval(wv
);
525 bool insn_is_b
= (((val
>> 28) & 0xf) <= 0xe)
526 && ((val
& 0x0f000000UL
) == 0x0a000000UL
);
527 bool insn_is_uncond_bl
= (val
& 0xff000000UL
) == 0xeb000000UL
;
528 bool insn_is_cond_bl
= (((val
>> 28) & 0xf) < 0xe)
529 && ((val
& 0x0f000000UL
) == 0x0b000000UL
);
530 bool insn_is_blx
= (val
& 0xfe000000UL
) == 0xfa000000UL
;
531 bool insn_is_any_branch
= (val
& 0x0e000000UL
) == 0x0a000000UL
;
533 if (r_type
== elfcpp::R_ARM_CALL
)
535 if (!insn_is_uncond_bl
&& !insn_is_blx
)
536 return This::STATUS_BAD_RELOC
;
538 else if (r_type
== elfcpp::R_ARM_JUMP24
)
540 if (!insn_is_b
&& !insn_is_cond_bl
)
541 return This::STATUS_BAD_RELOC
;
543 else if (r_type
== elfcpp::R_ARM_PLT32
)
545 if (!insn_is_any_branch
)
546 return This::STATUS_BAD_RELOC
;
551 Valtype addend
= utils::sign_extend
<26>(val
<< 2);
552 Valtype x
= (This::arm_symbol_value(object
, psymval
, addend
, has_thumb_bit
)
555 // If target has thumb bit set, we need to either turn the BL
556 // into a BLX (for ARMv5 or above) or generate a stub.
560 if (insn_is_uncond_bl
)
561 val
= (val
& 0xffffff) | 0xfa000000 | ((x
& 2) << 23);
563 return This::STATUS_BAD_RELOC
;
566 gold_assert(!insn_is_blx
);
568 val
= utils::bit_select(val
, (x
>> 2), 0xffffffUL
);
569 elfcpp::Swap
<32, big_endian
>::writeval(wv
, val
);
570 return (utils::has_overflow
<26>(x
)
571 ? This::STATUS_OVERFLOW
: This::STATUS_OKAY
);
577 static inline typename
This::Status
578 abs8(unsigned char *view
,
579 const Sized_relobj
<32, big_endian
>* object
,
580 const Symbol_value
<32>* psymval
, bool has_thumb_bit
)
582 typedef typename
elfcpp::Swap
<8, big_endian
>::Valtype Valtype
;
583 typedef typename
elfcpp::Swap
<32, big_endian
>::Valtype Reltype
;
584 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
585 Valtype val
= elfcpp::Swap
<8, big_endian
>::readval(wv
);
586 Reltype addend
= utils::sign_extend
<8>(val
);
587 Reltype x
= This::arm_symbol_value(object
, psymval
, addend
, has_thumb_bit
);
588 val
= utils::bit_select(val
, x
, 0xffU
);
589 elfcpp::Swap
<8, big_endian
>::writeval(wv
, val
);
590 return (utils::has_signed_unsigned_overflow
<8>(x
)
591 ? This::STATUS_OVERFLOW
592 : This::STATUS_OKAY
);
595 // R_ARM_ABS32: (S + A) | T
596 static inline typename
This::Status
597 abs32(unsigned char *view
,
598 const Sized_relobj
<32, big_endian
>* object
,
599 const Symbol_value
<32>* psymval
,
602 typedef typename
elfcpp::Swap
<32, big_endian
>::Valtype Valtype
;
603 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
604 Valtype addend
= elfcpp::Swap
<32, big_endian
>::readval(wv
);
605 Valtype x
= This::arm_symbol_value(object
, psymval
, addend
, has_thumb_bit
);
606 elfcpp::Swap
<32, big_endian
>::writeval(wv
, x
);
607 return This::STATUS_OKAY
;
610 // R_ARM_REL32: (S + A) | T - P
611 static inline typename
This::Status
612 rel32(unsigned char *view
,
613 const Sized_relobj
<32, big_endian
>* object
,
614 const Symbol_value
<32>* psymval
,
615 elfcpp::Elf_types
<32>::Elf_Addr address
,
618 typedef typename
elfcpp::Swap
<32, big_endian
>::Valtype Valtype
;
619 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
620 Valtype addend
= elfcpp::Swap
<32, big_endian
>::readval(wv
);
621 Valtype x
= (This::arm_symbol_value(object
, psymval
, addend
, has_thumb_bit
)
623 elfcpp::Swap
<32, big_endian
>::writeval(wv
, x
);
624 return This::STATUS_OKAY
;
627 // R_ARM_THM_CALL: (S + A) | T - P
628 static inline typename
This::Status
629 thm_call(unsigned char *view
,
630 const Sized_relobj
<32, big_endian
>* object
,
631 const Symbol_value
<32>* psymval
,
632 elfcpp::Elf_types
<32>::Elf_Addr address
,
635 // A thumb call consists of two instructions.
636 typedef typename
elfcpp::Swap
<16, big_endian
>::Valtype Valtype
;
637 typedef typename
elfcpp::Swap
<32, big_endian
>::Valtype Reltype
;
638 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
639 Valtype hi
= elfcpp::Swap
<16, big_endian
>::readval(wv
);
640 Valtype lo
= elfcpp::Swap
<16, big_endian
>::readval(wv
+ 1);
641 // Must be a BL instruction. lo == 11111xxxxxxxxxxx.
642 gold_assert((lo
& 0xf800) == 0xf800);
643 Reltype addend
= utils::sign_extend
<23>(((hi
& 0x7ff) << 12)
644 | ((lo
& 0x7ff) << 1));
645 Reltype x
= (This::arm_symbol_value(object
, psymval
, addend
, has_thumb_bit
)
648 // If target has no thumb bit set, we need to either turn the BL
649 // into a BLX (for ARMv5 or above) or generate a stub.
652 // This only works for ARMv5 and above with interworking enabled.
655 hi
= utils::bit_select(hi
, (x
>> 12), 0x7ffU
);
656 lo
= utils::bit_select(lo
, (x
>> 1), 0x7ffU
);
657 elfcpp::Swap
<16, big_endian
>::writeval(wv
, hi
);
658 elfcpp::Swap
<16, big_endian
>::writeval(wv
+ 1, lo
);
659 return (utils::has_overflow
<23>(x
)
660 ? This::STATUS_OVERFLOW
661 : This::STATUS_OKAY
);
664 // R_ARM_BASE_PREL: B(S) + A - P
665 static inline typename
This::Status
666 base_prel(unsigned char* view
,
667 elfcpp::Elf_types
<32>::Elf_Addr origin
,
668 elfcpp::Elf_types
<32>::Elf_Addr address
)
670 Base::rel32(view
, origin
- address
);
674 // R_ARM_GOT_BREL: GOT(S) + A - GOT_ORG
675 static inline typename
This::Status
676 got_brel(unsigned char* view
,
677 typename
elfcpp::Swap
<32, big_endian
>::Valtype got_offset
)
679 Base::rel32(view
, got_offset
);
680 return This::STATUS_OKAY
;
683 // R_ARM_PLT32: (S + A) | T - P
684 static inline typename
This::Status
685 plt32(unsigned char *view
,
686 const Sized_relobj
<32, big_endian
>* object
,
687 const Symbol_value
<32>* psymval
,
688 elfcpp::Elf_types
<32>::Elf_Addr address
,
691 return arm_branch_common
<elfcpp::R_ARM_PLT32
>(view
, object
, psymval
,
692 address
, has_thumb_bit
);
695 // R_ARM_CALL: (S + A) | T - P
696 static inline typename
This::Status
697 call(unsigned char *view
,
698 const Sized_relobj
<32, big_endian
>* object
,
699 const Symbol_value
<32>* psymval
,
700 elfcpp::Elf_types
<32>::Elf_Addr address
,
703 return arm_branch_common
<elfcpp::R_ARM_CALL
>(view
, object
, psymval
,
704 address
, has_thumb_bit
);
707 // R_ARM_JUMP24: (S + A) | T - P
708 static inline typename
This::Status
709 jump24(unsigned char *view
,
710 const Sized_relobj
<32, big_endian
>* object
,
711 const Symbol_value
<32>* psymval
,
712 elfcpp::Elf_types
<32>::Elf_Addr address
,
715 return arm_branch_common
<elfcpp::R_ARM_JUMP24
>(view
, object
, psymval
,
716 address
, has_thumb_bit
);
719 // R_ARM_PREL: (S + A) | T - P
720 static inline typename
This::Status
721 prel31(unsigned char *view
,
722 const Sized_relobj
<32, big_endian
>* object
,
723 const Symbol_value
<32>* psymval
,
724 elfcpp::Elf_types
<32>::Elf_Addr address
,
727 typedef typename
elfcpp::Swap
<32, big_endian
>::Valtype Valtype
;
728 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
729 Valtype val
= elfcpp::Swap
<32, big_endian
>::readval(wv
);
730 Valtype addend
= utils::sign_extend
<31>(val
);
731 Valtype x
= (This::arm_symbol_value(object
, psymval
, addend
, has_thumb_bit
)
733 val
= utils::bit_select(val
, x
, 0x7fffffffU
);
734 elfcpp::Swap
<32, big_endian
>::writeval(wv
, val
);
735 return (utils::has_overflow
<31>(x
) ?
736 This::STATUS_OVERFLOW
: This::STATUS_OKAY
);
740 // Get the GOT section, creating it if necessary.
742 template<bool big_endian
>
743 Output_data_got
<32, big_endian
>*
744 Target_arm
<big_endian
>::got_section(Symbol_table
* symtab
, Layout
* layout
)
746 if (this->got_
== NULL
)
748 gold_assert(symtab
!= NULL
&& layout
!= NULL
);
750 this->got_
= new Output_data_got
<32, big_endian
>();
753 os
= layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
755 | elfcpp::SHF_WRITE
),
759 // The old GNU linker creates a .got.plt section. We just
760 // create another set of data in the .got section. Note that we
761 // always create a PLT if we create a GOT, although the PLT
763 this->got_plt_
= new Output_data_space(4, "** GOT PLT");
764 os
= layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
766 | elfcpp::SHF_WRITE
),
770 // The first three entries are reserved.
771 this->got_plt_
->set_current_data_size(3 * 4);
773 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
774 symtab
->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL
,
776 0, 0, elfcpp::STT_OBJECT
,
778 elfcpp::STV_HIDDEN
, 0,
784 // Get the dynamic reloc section, creating it if necessary.
786 template<bool big_endian
>
787 typename Target_arm
<big_endian
>::Reloc_section
*
788 Target_arm
<big_endian
>::rel_dyn_section(Layout
* layout
)
790 if (this->rel_dyn_
== NULL
)
792 gold_assert(layout
!= NULL
);
793 this->rel_dyn_
= new Reloc_section(parameters
->options().combreloc());
794 layout
->add_output_section_data(".rel.dyn", elfcpp::SHT_REL
,
795 elfcpp::SHF_ALLOC
, this->rel_dyn_
);
797 return this->rel_dyn_
;
800 // A class to handle the PLT data.
802 template<bool big_endian
>
803 class Output_data_plt_arm
: public Output_section_data
806 typedef Output_data_reloc
<elfcpp::SHT_REL
, true, 32, big_endian
>
809 Output_data_plt_arm(Layout
*, Output_data_space
*);
811 // Add an entry to the PLT.
813 add_entry(Symbol
* gsym
);
815 // Return the .rel.plt section data.
818 { return this->rel_
; }
822 do_adjust_output_section(Output_section
* os
);
824 // Write to a map file.
826 do_print_to_mapfile(Mapfile
* mapfile
) const
827 { mapfile
->print_output_data(this, _("** PLT")); }
830 // Template for the first PLT entry.
831 static const uint32_t first_plt_entry
[5];
833 // Template for subsequent PLT entries.
834 static const uint32_t plt_entry
[3];
836 // Set the final size.
838 set_final_data_size()
840 this->set_data_size(sizeof(first_plt_entry
)
841 + this->count_
* sizeof(plt_entry
));
844 // Write out the PLT data.
846 do_write(Output_file
*);
848 // The reloc section.
850 // The .got.plt section.
851 Output_data_space
* got_plt_
;
852 // The number of PLT entries.
856 // Create the PLT section. The ordinary .got section is an argument,
857 // since we need to refer to the start. We also create our own .got
858 // section just for PLT entries.
860 template<bool big_endian
>
861 Output_data_plt_arm
<big_endian
>::Output_data_plt_arm(Layout
* layout
,
862 Output_data_space
* got_plt
)
863 : Output_section_data(4), got_plt_(got_plt
), count_(0)
865 this->rel_
= new Reloc_section(false);
866 layout
->add_output_section_data(".rel.plt", elfcpp::SHT_REL
,
867 elfcpp::SHF_ALLOC
, this->rel_
);
870 template<bool big_endian
>
872 Output_data_plt_arm
<big_endian
>::do_adjust_output_section(Output_section
* os
)
877 // Add an entry to the PLT.
879 template<bool big_endian
>
881 Output_data_plt_arm
<big_endian
>::add_entry(Symbol
* gsym
)
883 gold_assert(!gsym
->has_plt_offset());
885 // Note that when setting the PLT offset we skip the initial
886 // reserved PLT entry.
887 gsym
->set_plt_offset((this->count_
) * sizeof(plt_entry
)
888 + sizeof(first_plt_entry
));
892 section_offset_type got_offset
= this->got_plt_
->current_data_size();
894 // Every PLT entry needs a GOT entry which points back to the PLT
895 // entry (this will be changed by the dynamic linker, normally
896 // lazily when the function is called).
897 this->got_plt_
->set_current_data_size(got_offset
+ 4);
899 // Every PLT entry needs a reloc.
900 gsym
->set_needs_dynsym_entry();
901 this->rel_
->add_global(gsym
, elfcpp::R_ARM_JUMP_SLOT
, this->got_plt_
,
904 // Note that we don't need to save the symbol. The contents of the
905 // PLT are independent of which symbols are used. The symbols only
906 // appear in the relocations.
910 // FIXME: This is not very flexible. Right now this has only been tested
911 // on armv5te. If we are to support additional architecture features like
912 // Thumb-2 or BE8, we need to make this more flexible like GNU ld.
914 // The first entry in the PLT.
915 template<bool big_endian
>
916 const uint32_t Output_data_plt_arm
<big_endian
>::first_plt_entry
[5] =
918 0xe52de004, // str lr, [sp, #-4]!
919 0xe59fe004, // ldr lr, [pc, #4]
920 0xe08fe00e, // add lr, pc, lr
921 0xe5bef008, // ldr pc, [lr, #8]!
922 0x00000000, // &GOT[0] - .
925 // Subsequent entries in the PLT.
927 template<bool big_endian
>
928 const uint32_t Output_data_plt_arm
<big_endian
>::plt_entry
[3] =
930 0xe28fc600, // add ip, pc, #0xNN00000
931 0xe28cca00, // add ip, ip, #0xNN000
932 0xe5bcf000, // ldr pc, [ip, #0xNNN]!
935 // Write out the PLT. This uses the hand-coded instructions above,
936 // and adjusts them as needed. This is all specified by the arm ELF
937 // Processor Supplement.
939 template<bool big_endian
>
941 Output_data_plt_arm
<big_endian
>::do_write(Output_file
* of
)
943 const off_t offset
= this->offset();
944 const section_size_type oview_size
=
945 convert_to_section_size_type(this->data_size());
946 unsigned char* const oview
= of
->get_output_view(offset
, oview_size
);
948 const off_t got_file_offset
= this->got_plt_
->offset();
949 const section_size_type got_size
=
950 convert_to_section_size_type(this->got_plt_
->data_size());
951 unsigned char* const got_view
= of
->get_output_view(got_file_offset
,
953 unsigned char* pov
= oview
;
955 elfcpp::Elf_types
<32>::Elf_Addr plt_address
= this->address();
956 elfcpp::Elf_types
<32>::Elf_Addr got_address
= this->got_plt_
->address();
958 // Write first PLT entry. All but the last word are constants.
959 const size_t num_first_plt_words
= (sizeof(first_plt_entry
)
960 / sizeof(plt_entry
[0]));
961 for (size_t i
= 0; i
< num_first_plt_words
- 1; i
++)
962 elfcpp::Swap
<32, big_endian
>::writeval(pov
+ i
* 4, first_plt_entry
[i
]);
963 // Last word in first PLT entry is &GOT[0] - .
964 elfcpp::Swap
<32, big_endian
>::writeval(pov
+ 16,
965 got_address
- (plt_address
+ 16));
966 pov
+= sizeof(first_plt_entry
);
968 unsigned char* got_pov
= got_view
;
970 memset(got_pov
, 0, 12);
973 const int rel_size
= elfcpp::Elf_sizes
<32>::rel_size
;
974 unsigned int plt_offset
= sizeof(first_plt_entry
);
975 unsigned int plt_rel_offset
= 0;
976 unsigned int got_offset
= 12;
977 const unsigned int count
= this->count_
;
978 for (unsigned int i
= 0;
981 pov
+= sizeof(plt_entry
),
983 plt_offset
+= sizeof(plt_entry
),
984 plt_rel_offset
+= rel_size
,
987 // Set and adjust the PLT entry itself.
988 int32_t offset
= ((got_address
+ got_offset
)
989 - (plt_address
+ plt_offset
+ 8));
991 gold_assert(offset
>= 0 && offset
< 0x0fffffff);
992 uint32_t plt_insn0
= plt_entry
[0] | ((offset
>> 20) & 0xff);
993 elfcpp::Swap
<32, big_endian
>::writeval(pov
, plt_insn0
);
994 uint32_t plt_insn1
= plt_entry
[1] | ((offset
>> 12) & 0xff);
995 elfcpp::Swap
<32, big_endian
>::writeval(pov
+ 4, plt_insn1
);
996 uint32_t plt_insn2
= plt_entry
[2] | (offset
& 0xfff);
997 elfcpp::Swap
<32, big_endian
>::writeval(pov
+ 8, plt_insn2
);
999 // Set the entry in the GOT.
1000 elfcpp::Swap
<32, big_endian
>::writeval(got_pov
, plt_address
);
1003 gold_assert(static_cast<section_size_type
>(pov
- oview
) == oview_size
);
1004 gold_assert(static_cast<section_size_type
>(got_pov
- got_view
) == got_size
);
1006 of
->write_output_view(offset
, oview_size
, oview
);
1007 of
->write_output_view(got_file_offset
, got_size
, got_view
);
1010 // Create a PLT entry for a global symbol.
1012 template<bool big_endian
>
1014 Target_arm
<big_endian
>::make_plt_entry(Symbol_table
* symtab
, Layout
* layout
,
1017 if (gsym
->has_plt_offset())
1020 if (this->plt_
== NULL
)
1022 // Create the GOT sections first.
1023 this->got_section(symtab
, layout
);
1025 this->plt_
= new Output_data_plt_arm
<big_endian
>(layout
, this->got_plt_
);
1026 layout
->add_output_section_data(".plt", elfcpp::SHT_PROGBITS
,
1028 | elfcpp::SHF_EXECINSTR
),
1031 this->plt_
->add_entry(gsym
);
1034 // Report an unsupported relocation against a local symbol.
1036 template<bool big_endian
>
1038 Target_arm
<big_endian
>::Scan::unsupported_reloc_local(
1039 Sized_relobj
<32, big_endian
>* object
,
1040 unsigned int r_type
)
1042 gold_error(_("%s: unsupported reloc %u against local symbol"),
1043 object
->name().c_str(), r_type
);
1046 // We are about to emit a dynamic relocation of type R_TYPE. If the
1047 // dynamic linker does not support it, issue an error. The GNU linker
1048 // only issues a non-PIC error for an allocated read-only section.
1049 // Here we know the section is allocated, but we don't know that it is
1050 // read-only. But we check for all the relocation types which the
1051 // glibc dynamic linker supports, so it seems appropriate to issue an
1052 // error even if the section is not read-only.
1054 template<bool big_endian
>
1056 Target_arm
<big_endian
>::Scan::check_non_pic(Relobj
* object
,
1057 unsigned int r_type
)
1061 // These are the relocation types supported by glibc for ARM.
1062 case elfcpp::R_ARM_RELATIVE
:
1063 case elfcpp::R_ARM_COPY
:
1064 case elfcpp::R_ARM_GLOB_DAT
:
1065 case elfcpp::R_ARM_JUMP_SLOT
:
1066 case elfcpp::R_ARM_ABS32
:
1067 case elfcpp::R_ARM_PC24
:
1068 // FIXME: The following 3 types are not supported by Android's dynamic
1070 case elfcpp::R_ARM_TLS_DTPMOD32
:
1071 case elfcpp::R_ARM_TLS_DTPOFF32
:
1072 case elfcpp::R_ARM_TLS_TPOFF32
:
1076 // This prevents us from issuing more than one error per reloc
1077 // section. But we can still wind up issuing more than one
1078 // error per object file.
1079 if (this->issued_non_pic_error_
)
1081 object
->error(_("requires unsupported dynamic reloc; "
1082 "recompile with -fPIC"));
1083 this->issued_non_pic_error_
= true;
1086 case elfcpp::R_ARM_NONE
:
1091 // Scan a relocation for a local symbol.
1092 // FIXME: This only handles a subset of relocation types used by Android
1093 // on ARM v5te devices.
1095 template<bool big_endian
>
1097 Target_arm
<big_endian
>::Scan::local(const General_options
&,
1098 Symbol_table
* symtab
,
1101 Sized_relobj
<32, big_endian
>* object
,
1102 unsigned int data_shndx
,
1103 Output_section
* output_section
,
1104 const elfcpp::Rel
<32, big_endian
>& reloc
,
1105 unsigned int r_type
,
1106 const elfcpp::Sym
<32, big_endian
>&)
1108 r_type
= get_real_reloc_type(r_type
);
1111 case elfcpp::R_ARM_NONE
:
1114 case elfcpp::R_ARM_ABS8
:
1115 if (parameters
->options().output_is_position_independent())
1117 // FIXME: Create a dynamic relocation for this location.
1118 gold_error(_("%s: gold bug: need dynamic ABS8 reloc"),
1119 object
->name().c_str());
1123 case elfcpp::R_ARM_ABS32
:
1124 // If building a shared library (or a position-independent
1125 // executable), we need to create a dynamic relocation for
1126 // this location. The relocation applied at link time will
1127 // apply the link-time value, so we flag the location with
1128 // an R_ARM_RELATIVE relocation so the dynamic loader can
1129 // relocate it easily.
1130 if (parameters
->options().output_is_position_independent())
1132 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1133 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(reloc
.get_r_info());
1134 // If we are to add more other reloc types than R_ARM_ABS32,
1135 // we need to add check_non_pic(object, r_type) here.
1136 rel_dyn
->add_local_relative(object
, r_sym
, elfcpp::R_ARM_RELATIVE
,
1137 output_section
, data_shndx
,
1138 reloc
.get_r_offset());
1142 case elfcpp::R_ARM_REL32
:
1143 case elfcpp::R_ARM_THM_CALL
:
1144 case elfcpp::R_ARM_CALL
:
1145 case elfcpp::R_ARM_PREL31
:
1146 case elfcpp::R_ARM_JUMP24
:
1147 case elfcpp::R_ARM_PLT32
:
1150 case elfcpp::R_ARM_GOTOFF32
:
1151 // We need a GOT section:
1152 target
->got_section(symtab
, layout
);
1155 case elfcpp::R_ARM_BASE_PREL
:
1156 // FIXME: What about this?
1159 case elfcpp::R_ARM_GOT_BREL
:
1161 // The symbol requires a GOT entry.
1162 Output_data_got
<32, big_endian
>* got
=
1163 target
->got_section(symtab
, layout
);
1164 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(reloc
.get_r_info());
1165 if (got
->add_local(object
, r_sym
, GOT_TYPE_STANDARD
))
1167 // If we are generating a shared object, we need to add a
1168 // dynamic RELATIVE relocation for this symbol's GOT entry.
1169 if (parameters
->options().output_is_position_independent())
1171 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1172 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(reloc
.get_r_info());
1173 rel_dyn
->add_local_relative(
1174 object
, r_sym
, elfcpp::R_ARM_RELATIVE
, got
,
1175 object
->local_got_offset(r_sym
, GOT_TYPE_STANDARD
));
1181 case elfcpp::R_ARM_TARGET1
:
1182 // This should have been mapped to another type already.
1184 case elfcpp::R_ARM_COPY
:
1185 case elfcpp::R_ARM_GLOB_DAT
:
1186 case elfcpp::R_ARM_JUMP_SLOT
:
1187 case elfcpp::R_ARM_RELATIVE
:
1188 // These are relocations which should only be seen by the
1189 // dynamic linker, and should never be seen here.
1190 gold_error(_("%s: unexpected reloc %u in object file"),
1191 object
->name().c_str(), r_type
);
1195 unsupported_reloc_local(object
, r_type
);
1200 // Report an unsupported relocation against a global symbol.
1202 template<bool big_endian
>
1204 Target_arm
<big_endian
>::Scan::unsupported_reloc_global(
1205 Sized_relobj
<32, big_endian
>* object
,
1206 unsigned int r_type
,
1209 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1210 object
->name().c_str(), r_type
, gsym
->demangled_name().c_str());
1213 // Scan a relocation for a global symbol.
1214 // FIXME: This only handles a subset of relocation types used by Android
1215 // on ARM v5te devices.
1217 template<bool big_endian
>
1219 Target_arm
<big_endian
>::Scan::global(const General_options
&,
1220 Symbol_table
* symtab
,
1223 Sized_relobj
<32, big_endian
>* object
,
1224 unsigned int data_shndx
,
1225 Output_section
* output_section
,
1226 const elfcpp::Rel
<32, big_endian
>& reloc
,
1227 unsigned int r_type
,
1230 r_type
= get_real_reloc_type(r_type
);
1233 case elfcpp::R_ARM_NONE
:
1236 case elfcpp::R_ARM_ABS8
:
1237 // Make a dynamic relocation if necessary.
1238 if (gsym
->needs_dynamic_reloc(Symbol::ABSOLUTE_REF
))
1240 // FIXME: Create a dynamic relocation for this location.
1241 gold_error(_("%s: gold bug: need dynamic ABS8 reloc for %s"),
1242 object
->name().c_str(), gsym
->demangled_name().c_str());
1246 case elfcpp::R_ARM_ABS32
:
1248 // Make a dynamic relocation if necessary.
1249 if (gsym
->needs_dynamic_reloc(Symbol::ABSOLUTE_REF
))
1251 if (target
->may_need_copy_reloc(gsym
))
1253 target
->copy_reloc(symtab
, layout
, object
,
1254 data_shndx
, output_section
, gsym
, reloc
);
1256 else if (gsym
->can_use_relative_reloc(false))
1258 // If we are to add more other reloc types than R_ARM_ABS32,
1259 // we need to add check_non_pic(object, r_type) here.
1260 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1261 rel_dyn
->add_global_relative(gsym
, elfcpp::R_ARM_RELATIVE
,
1262 output_section
, object
,
1263 data_shndx
, reloc
.get_r_offset());
1267 // If we are to add more other reloc types than R_ARM_ABS32,
1268 // we need to add check_non_pic(object, r_type) here.
1269 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1270 rel_dyn
->add_global(gsym
, r_type
, output_section
, object
,
1271 data_shndx
, reloc
.get_r_offset());
1277 case elfcpp::R_ARM_REL32
:
1278 case elfcpp::R_ARM_PREL31
:
1280 // Make a dynamic relocation if necessary.
1281 int flags
= Symbol::NON_PIC_REF
;
1282 if (gsym
->needs_dynamic_reloc(flags
))
1284 if (target
->may_need_copy_reloc(gsym
))
1286 target
->copy_reloc(symtab
, layout
, object
,
1287 data_shndx
, output_section
, gsym
, reloc
);
1291 check_non_pic(object
, r_type
);
1292 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1293 rel_dyn
->add_global(gsym
, r_type
, output_section
, object
,
1294 data_shndx
, reloc
.get_r_offset());
1300 case elfcpp::R_ARM_JUMP24
:
1301 case elfcpp::R_ARM_THM_CALL
:
1302 case elfcpp::R_ARM_CALL
:
1304 if (Target_arm
<big_endian
>::Scan::symbol_needs_plt_entry(gsym
))
1305 target
->make_plt_entry(symtab
, layout
, gsym
);
1306 // Make a dynamic relocation if necessary.
1307 int flags
= Symbol::NON_PIC_REF
;
1308 if (gsym
->type() == elfcpp::STT_FUNC
1309 || gsym
->type() == elfcpp::STT_ARM_TFUNC
)
1310 flags
|= Symbol::FUNCTION_CALL
;
1311 if (gsym
->needs_dynamic_reloc(flags
))
1313 if (target
->may_need_copy_reloc(gsym
))
1315 target
->copy_reloc(symtab
, layout
, object
,
1316 data_shndx
, output_section
, gsym
,
1321 check_non_pic(object
, r_type
);
1322 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1323 rel_dyn
->add_global(gsym
, r_type
, output_section
, object
,
1324 data_shndx
, reloc
.get_r_offset());
1330 case elfcpp::R_ARM_PLT32
:
1331 // If the symbol is fully resolved, this is just a relative
1332 // local reloc. Otherwise we need a PLT entry.
1333 if (gsym
->final_value_is_known())
1335 // If building a shared library, we can also skip the PLT entry
1336 // if the symbol is defined in the output file and is protected
1338 if (gsym
->is_defined()
1339 && !gsym
->is_from_dynobj()
1340 && !gsym
->is_preemptible())
1342 target
->make_plt_entry(symtab
, layout
, gsym
);
1345 case elfcpp::R_ARM_GOTOFF32
:
1346 // We need a GOT section.
1347 target
->got_section(symtab
, layout
);
1350 case elfcpp::R_ARM_BASE_PREL
:
1351 // FIXME: What about this?
1354 case elfcpp::R_ARM_GOT_BREL
:
1356 // The symbol requires a GOT entry.
1357 Output_data_got
<32, big_endian
>* got
=
1358 target
->got_section(symtab
, layout
);
1359 if (gsym
->final_value_is_known())
1360 got
->add_global(gsym
, GOT_TYPE_STANDARD
);
1363 // If this symbol is not fully resolved, we need to add a
1364 // GOT entry with a dynamic relocation.
1365 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1366 if (gsym
->is_from_dynobj()
1367 || gsym
->is_undefined()
1368 || gsym
->is_preemptible())
1369 got
->add_global_with_rel(gsym
, GOT_TYPE_STANDARD
,
1370 rel_dyn
, elfcpp::R_ARM_GLOB_DAT
);
1373 if (got
->add_global(gsym
, GOT_TYPE_STANDARD
))
1374 rel_dyn
->add_global_relative(
1375 gsym
, elfcpp::R_ARM_RELATIVE
, got
,
1376 gsym
->got_offset(GOT_TYPE_STANDARD
));
1382 case elfcpp::R_ARM_TARGET1
:
1383 // This should have been mapped to another type already.
1385 case elfcpp::R_ARM_COPY
:
1386 case elfcpp::R_ARM_GLOB_DAT
:
1387 case elfcpp::R_ARM_JUMP_SLOT
:
1388 case elfcpp::R_ARM_RELATIVE
:
1389 // These are relocations which should only be seen by the
1390 // dynamic linker, and should never be seen here.
1391 gold_error(_("%s: unexpected reloc %u in object file"),
1392 object
->name().c_str(), r_type
);
1396 unsupported_reloc_global(object
, r_type
, gsym
);
1401 // Process relocations for gc.
1403 template<bool big_endian
>
1405 Target_arm
<big_endian
>::gc_process_relocs(const General_options
& options
,
1406 Symbol_table
* symtab
,
1408 Sized_relobj
<32, big_endian
>* object
,
1409 unsigned int data_shndx
,
1411 const unsigned char* prelocs
,
1413 Output_section
* output_section
,
1414 bool needs_special_offset_handling
,
1415 size_t local_symbol_count
,
1416 const unsigned char* plocal_symbols
)
1418 typedef Target_arm
<big_endian
> Arm
;
1419 typedef typename Target_arm
<big_endian
>::Scan Scan
;
1421 gold::gc_process_relocs
<32, big_endian
, Arm
, elfcpp::SHT_REL
, Scan
>(
1431 needs_special_offset_handling
,
1436 // Scan relocations for a section.
1438 template<bool big_endian
>
1440 Target_arm
<big_endian
>::scan_relocs(const General_options
& options
,
1441 Symbol_table
* symtab
,
1443 Sized_relobj
<32, big_endian
>* object
,
1444 unsigned int data_shndx
,
1445 unsigned int sh_type
,
1446 const unsigned char* prelocs
,
1448 Output_section
* output_section
,
1449 bool needs_special_offset_handling
,
1450 size_t local_symbol_count
,
1451 const unsigned char* plocal_symbols
)
1453 typedef typename Target_arm
<big_endian
>::Scan Scan
;
1454 if (sh_type
== elfcpp::SHT_RELA
)
1456 gold_error(_("%s: unsupported RELA reloc section"),
1457 object
->name().c_str());
1461 gold::scan_relocs
<32, big_endian
, Target_arm
, elfcpp::SHT_REL
, Scan
>(
1471 needs_special_offset_handling
,
1476 // Finalize the sections.
1478 template<bool big_endian
>
1480 Target_arm
<big_endian
>::do_finalize_sections(Layout
* layout
)
1482 // Fill in some more dynamic tags.
1483 Output_data_dynamic
* const odyn
= layout
->dynamic_data();
1486 if (this->got_plt_
!= NULL
)
1487 odyn
->add_section_address(elfcpp::DT_PLTGOT
, this->got_plt_
);
1489 if (this->plt_
!= NULL
)
1491 const Output_data
* od
= this->plt_
->rel_plt();
1492 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, od
);
1493 odyn
->add_section_address(elfcpp::DT_JMPREL
, od
);
1494 odyn
->add_constant(elfcpp::DT_PLTREL
, elfcpp::DT_REL
);
1497 if (this->rel_dyn_
!= NULL
)
1499 const Output_data
* od
= this->rel_dyn_
;
1500 odyn
->add_section_address(elfcpp::DT_REL
, od
);
1501 odyn
->add_section_size(elfcpp::DT_RELSZ
, od
);
1502 odyn
->add_constant(elfcpp::DT_RELENT
,
1503 elfcpp::Elf_sizes
<32>::rel_size
);
1506 if (!parameters
->options().shared())
1508 // The value of the DT_DEBUG tag is filled in by the dynamic
1509 // linker at run time, and used by the debugger.
1510 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
1514 // Emit any relocs we saved in an attempt to avoid generating COPY
1516 if (this->copy_relocs_
.any_saved_relocs())
1517 this->copy_relocs_
.emit(this->rel_dyn_section(layout
));
1519 // For the ARM target, we need to add a PT_ARM_EXIDX segment for
1520 // the .ARM.exidx section.
1521 if (!layout
->script_options()->saw_phdrs_clause()
1522 && !parameters
->options().relocatable())
1524 Output_section
* exidx_section
=
1525 layout
->find_output_section(".ARM.exidx");
1527 if (exidx_section
!= NULL
1528 && exidx_section
->type() == elfcpp::SHT_ARM_EXIDX
)
1530 gold_assert(layout
->find_output_segment(elfcpp::PT_ARM_EXIDX
, 0, 0)
1532 Output_segment
* exidx_segment
=
1533 layout
->make_output_segment(elfcpp::PT_ARM_EXIDX
, elfcpp::PF_R
);
1534 exidx_segment
->add_output_section(exidx_section
, elfcpp::PF_R
);
1539 // Return whether a direct absolute static relocation needs to be applied.
1540 // In cases where Scan::local() or Scan::global() has created
1541 // a dynamic relocation other than R_ARM_RELATIVE, the addend
1542 // of the relocation is carried in the data, and we must not
1543 // apply the static relocation.
1545 template<bool big_endian
>
1547 Target_arm
<big_endian
>::Relocate::should_apply_static_reloc(
1548 const Sized_symbol
<32>* gsym
,
1551 Output_section
* output_section
)
1553 // If the output section is not allocated, then we didn't call
1554 // scan_relocs, we didn't create a dynamic reloc, and we must apply
1556 if ((output_section
->flags() & elfcpp::SHF_ALLOC
) == 0)
1559 // For local symbols, we will have created a non-RELATIVE dynamic
1560 // relocation only if (a) the output is position independent,
1561 // (b) the relocation is absolute (not pc- or segment-relative), and
1562 // (c) the relocation is not 32 bits wide.
1564 return !(parameters
->options().output_is_position_independent()
1565 && (ref_flags
& Symbol::ABSOLUTE_REF
)
1568 // For global symbols, we use the same helper routines used in the
1569 // scan pass. If we did not create a dynamic relocation, or if we
1570 // created a RELATIVE dynamic relocation, we should apply the static
1572 bool has_dyn
= gsym
->needs_dynamic_reloc(ref_flags
);
1573 bool is_rel
= (ref_flags
& Symbol::ABSOLUTE_REF
)
1574 && gsym
->can_use_relative_reloc(ref_flags
1575 & Symbol::FUNCTION_CALL
);
1576 return !has_dyn
|| is_rel
;
1579 // Perform a relocation.
1581 template<bool big_endian
>
1583 Target_arm
<big_endian
>::Relocate::relocate(
1584 const Relocate_info
<32, big_endian
>* relinfo
,
1586 Output_section
*output_section
,
1588 const elfcpp::Rel
<32, big_endian
>& rel
,
1589 unsigned int r_type
,
1590 const Sized_symbol
<32>* gsym
,
1591 const Symbol_value
<32>* psymval
,
1592 unsigned char* view
,
1593 elfcpp::Elf_types
<32>::Elf_Addr address
,
1594 section_size_type
/* view_size */ )
1596 typedef Arm_relocate_functions
<big_endian
> Arm_relocate_functions
;
1598 r_type
= get_real_reloc_type(r_type
);
1600 // If this the symbol may be a Thumb function, set thumb bit to 1.
1601 bool has_thumb_bit
= ((gsym
!= NULL
)
1602 && (gsym
->type() == elfcpp::STT_FUNC
1603 || gsym
->type() == elfcpp::STT_ARM_TFUNC
));
1605 // Pick the value to use for symbols defined in shared objects.
1606 Symbol_value
<32> symval
;
1608 && gsym
->use_plt_offset(reloc_is_non_pic(r_type
)))
1610 symval
.set_output_value(target
->plt_section()->address()
1611 + gsym
->plt_offset());
1616 const Sized_relobj
<32, big_endian
>* object
= relinfo
->object
;
1618 // Get the GOT offset if needed.
1619 // The GOT pointer points to the end of the GOT section.
1620 // We need to subtract the size of the GOT section to get
1621 // the actual offset to use in the relocation.
1622 bool have_got_offset
= false;
1623 unsigned int got_offset
= 0;
1626 case elfcpp::R_ARM_GOT_BREL
:
1629 gold_assert(gsym
->has_got_offset(GOT_TYPE_STANDARD
));
1630 got_offset
= (gsym
->got_offset(GOT_TYPE_STANDARD
)
1631 - target
->got_size());
1635 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(rel
.get_r_info());
1636 gold_assert(object
->local_has_got_offset(r_sym
, GOT_TYPE_STANDARD
));
1637 got_offset
= (object
->local_got_offset(r_sym
, GOT_TYPE_STANDARD
)
1638 - target
->got_size());
1640 have_got_offset
= true;
1647 typename
Arm_relocate_functions::Status reloc_status
=
1648 Arm_relocate_functions::STATUS_OKAY
;
1651 case elfcpp::R_ARM_NONE
:
1654 case elfcpp::R_ARM_ABS8
:
1655 if (should_apply_static_reloc(gsym
, Symbol::ABSOLUTE_REF
, false,
1657 reloc_status
= Arm_relocate_functions::abs8(view
, object
, psymval
,
1661 case elfcpp::R_ARM_ABS32
:
1662 if (should_apply_static_reloc(gsym
, Symbol::ABSOLUTE_REF
, true,
1664 reloc_status
= Arm_relocate_functions::abs32(view
, object
, psymval
,
1668 case elfcpp::R_ARM_REL32
:
1669 reloc_status
= Arm_relocate_functions::rel32(view
, object
, psymval
,
1670 address
, has_thumb_bit
);
1673 case elfcpp::R_ARM_THM_CALL
:
1674 reloc_status
= Arm_relocate_functions::thm_call(view
, object
, psymval
,
1675 address
, has_thumb_bit
);
1678 case elfcpp::R_ARM_GOTOFF32
:
1680 elfcpp::Elf_types
<32>::Elf_Addr got_origin
;
1681 got_origin
= target
->got_plt_section()->address();
1682 reloc_status
= Arm_relocate_functions::rel32(view
, object
, psymval
,
1683 got_origin
, has_thumb_bit
);
1687 case elfcpp::R_ARM_BASE_PREL
:
1690 // Get the addressing origin of the output segment defining the
1691 // symbol gsym (AAELF 4.6.1.2 Relocation types)
1692 gold_assert(gsym
!= NULL
);
1693 if (gsym
->source() == Symbol::IN_OUTPUT_SEGMENT
)
1694 origin
= gsym
->output_segment()->vaddr();
1695 else if (gsym
->source () == Symbol::IN_OUTPUT_DATA
)
1696 origin
= gsym
->output_data()->address();
1699 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1700 _("cannot find origin of R_ARM_BASE_PREL"));
1703 reloc_status
= Arm_relocate_functions::base_prel(view
, origin
, address
);
1707 case elfcpp::R_ARM_GOT_BREL
:
1708 gold_assert(have_got_offset
);
1709 reloc_status
= Arm_relocate_functions::got_brel(view
, got_offset
);
1712 case elfcpp::R_ARM_PLT32
:
1713 gold_assert(gsym
== NULL
1714 || gsym
->has_plt_offset()
1715 || gsym
->final_value_is_known()
1716 || (gsym
->is_defined()
1717 && !gsym
->is_from_dynobj()
1718 && !gsym
->is_preemptible()));
1719 reloc_status
= Arm_relocate_functions::plt32(view
, object
, psymval
,
1720 address
, has_thumb_bit
);
1723 case elfcpp::R_ARM_CALL
:
1724 reloc_status
= Arm_relocate_functions::call(view
, object
, psymval
,
1725 address
, has_thumb_bit
);
1728 case elfcpp::R_ARM_JUMP24
:
1729 reloc_status
= Arm_relocate_functions::jump24(view
, object
, psymval
,
1730 address
, has_thumb_bit
);
1733 case elfcpp::R_ARM_PREL31
:
1734 reloc_status
= Arm_relocate_functions::prel31(view
, object
, psymval
,
1735 address
, has_thumb_bit
);
1738 case elfcpp::R_ARM_TARGET1
:
1739 // This should have been mapped to another type already.
1741 case elfcpp::R_ARM_COPY
:
1742 case elfcpp::R_ARM_GLOB_DAT
:
1743 case elfcpp::R_ARM_JUMP_SLOT
:
1744 case elfcpp::R_ARM_RELATIVE
:
1745 // These are relocations which should only be seen by the
1746 // dynamic linker, and should never be seen here.
1747 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1748 _("unexpected reloc %u in object file"),
1753 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1754 _("unsupported reloc %u"),
1759 // Report any errors.
1760 switch (reloc_status
)
1762 case Arm_relocate_functions::STATUS_OKAY
:
1764 case Arm_relocate_functions::STATUS_OVERFLOW
:
1765 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1766 _("relocation overflow in relocation %u"),
1769 case Arm_relocate_functions::STATUS_BAD_RELOC
:
1770 gold_error_at_location(
1774 _("unexpected opcode while processing relocation %u"),
1784 // Relocate section data.
1786 template<bool big_endian
>
1788 Target_arm
<big_endian
>::relocate_section(
1789 const Relocate_info
<32, big_endian
>* relinfo
,
1790 unsigned int sh_type
,
1791 const unsigned char* prelocs
,
1793 Output_section
* output_section
,
1794 bool needs_special_offset_handling
,
1795 unsigned char* view
,
1796 elfcpp::Elf_types
<32>::Elf_Addr address
,
1797 section_size_type view_size
)
1799 typedef typename Target_arm
<big_endian
>::Relocate Arm_relocate
;
1800 gold_assert(sh_type
== elfcpp::SHT_REL
);
1802 gold::relocate_section
<32, big_endian
, Target_arm
, elfcpp::SHT_REL
,
1809 needs_special_offset_handling
,
1815 // Return the size of a relocation while scanning during a relocatable
1818 template<bool big_endian
>
1820 Target_arm
<big_endian
>::Relocatable_size_for_reloc::get_size_for_reloc(
1821 unsigned int r_type
,
1824 r_type
= get_real_reloc_type(r_type
);
1827 case elfcpp::R_ARM_NONE
:
1830 case elfcpp::R_ARM_ABS8
:
1833 case elfcpp::R_ARM_ABS32
:
1834 case elfcpp::R_ARM_REL32
:
1835 case elfcpp::R_ARM_THM_CALL
:
1836 case elfcpp::R_ARM_GOTOFF32
:
1837 case elfcpp::R_ARM_BASE_PREL
:
1838 case elfcpp::R_ARM_GOT_BREL
:
1839 case elfcpp::R_ARM_PLT32
:
1840 case elfcpp::R_ARM_CALL
:
1841 case elfcpp::R_ARM_JUMP24
:
1842 case elfcpp::R_ARM_PREL31
:
1845 case elfcpp::R_ARM_TARGET1
:
1846 // This should have been mapped to another type already.
1848 case elfcpp::R_ARM_COPY
:
1849 case elfcpp::R_ARM_GLOB_DAT
:
1850 case elfcpp::R_ARM_JUMP_SLOT
:
1851 case elfcpp::R_ARM_RELATIVE
:
1852 // These are relocations which should only be seen by the
1853 // dynamic linker, and should never be seen here.
1854 gold_error(_("%s: unexpected reloc %u in object file"),
1855 object
->name().c_str(), r_type
);
1859 object
->error(_("unsupported reloc %u in object file"), r_type
);
1864 // Scan the relocs during a relocatable link.
1866 template<bool big_endian
>
1868 Target_arm
<big_endian
>::scan_relocatable_relocs(
1869 const General_options
& options
,
1870 Symbol_table
* symtab
,
1872 Sized_relobj
<32, big_endian
>* object
,
1873 unsigned int data_shndx
,
1874 unsigned int sh_type
,
1875 const unsigned char* prelocs
,
1877 Output_section
* output_section
,
1878 bool needs_special_offset_handling
,
1879 size_t local_symbol_count
,
1880 const unsigned char* plocal_symbols
,
1881 Relocatable_relocs
* rr
)
1883 gold_assert(sh_type
== elfcpp::SHT_REL
);
1885 typedef gold::Default_scan_relocatable_relocs
<elfcpp::SHT_REL
,
1886 Relocatable_size_for_reloc
> Scan_relocatable_relocs
;
1888 gold::scan_relocatable_relocs
<32, big_endian
, elfcpp::SHT_REL
,
1889 Scan_relocatable_relocs
>(
1898 needs_special_offset_handling
,
1904 // Relocate a section during a relocatable link.
1906 template<bool big_endian
>
1908 Target_arm
<big_endian
>::relocate_for_relocatable(
1909 const Relocate_info
<32, big_endian
>* relinfo
,
1910 unsigned int sh_type
,
1911 const unsigned char* prelocs
,
1913 Output_section
* output_section
,
1914 off_t offset_in_output_section
,
1915 const Relocatable_relocs
* rr
,
1916 unsigned char* view
,
1917 elfcpp::Elf_types
<32>::Elf_Addr view_address
,
1918 section_size_type view_size
,
1919 unsigned char* reloc_view
,
1920 section_size_type reloc_view_size
)
1922 gold_assert(sh_type
== elfcpp::SHT_REL
);
1924 gold::relocate_for_relocatable
<32, big_endian
, elfcpp::SHT_REL
>(
1929 offset_in_output_section
,
1938 // Return the value to use for a dynamic symbol which requires special
1939 // treatment. This is how we support equality comparisons of function
1940 // pointers across shared library boundaries, as described in the
1941 // processor specific ABI supplement.
1943 template<bool big_endian
>
1945 Target_arm
<big_endian
>::do_dynsym_value(const Symbol
* gsym
) const
1947 gold_assert(gsym
->is_from_dynobj() && gsym
->has_plt_offset());
1948 return this->plt_section()->address() + gsym
->plt_offset();
1951 // Map platform-specific relocs to real relocs
1953 template<bool big_endian
>
1955 Target_arm
<big_endian
>::get_real_reloc_type (unsigned int r_type
)
1959 case elfcpp::R_ARM_TARGET1
:
1960 // This is either R_ARM_ABS32 or R_ARM_REL32;
1961 return elfcpp::R_ARM_ABS32
;
1963 case elfcpp::R_ARM_TARGET2
:
1964 // This can be any reloc type but ususally is R_ARM_GOT_PREL
1965 return elfcpp::R_ARM_GOT_PREL
;
1972 // The selector for arm object files.
1974 template<bool big_endian
>
1975 class Target_selector_arm
: public Target_selector
1978 Target_selector_arm()
1979 : Target_selector(elfcpp::EM_ARM
, 32, big_endian
,
1980 (big_endian
? "elf32-bigarm" : "elf32-littlearm"))
1984 do_instantiate_target()
1985 { return new Target_arm
<big_endian
>(); }
1988 Target_selector_arm
<false> target_selector_arm
;
1989 Target_selector_arm
<true> target_selector_armbe
;
1991 } // End anonymous namespace.