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 (gsym
->type() != elfcpp::STT_ARM_TFUNC
409 && gsym
->may_need_copy_reloc());
412 // Add a potential copy relocation.
414 copy_reloc(Symbol_table
* symtab
, Layout
* layout
,
415 Sized_relobj
<32, big_endian
>* object
,
416 unsigned int shndx
, Output_section
* output_section
,
417 Symbol
* sym
, const elfcpp::Rel
<32, big_endian
>& reloc
)
419 this->copy_relocs_
.copy_reloc(symtab
, layout
,
420 symtab
->get_sized_symbol
<32>(sym
),
421 object
, shndx
, output_section
, reloc
,
422 this->rel_dyn_section(layout
));
425 // Information about this specific target which we pass to the
426 // general Target structure.
427 static const Target::Target_info arm_info
;
429 // The types of GOT entries needed for this platform.
432 GOT_TYPE_STANDARD
= 0 // GOT entry for a regular symbol
436 Output_data_got
<32, big_endian
>* got_
;
438 Output_data_plt_arm
<big_endian
>* plt_
;
439 // The GOT PLT section.
440 Output_data_space
* got_plt_
;
441 // The dynamic reloc section.
442 Reloc_section
* rel_dyn_
;
443 // Relocs saved to avoid a COPY reloc.
444 Copy_relocs
<elfcpp::SHT_REL
, 32, big_endian
> copy_relocs_
;
445 // Space for variables copied with a COPY reloc.
446 Output_data_space
* dynbss_
;
449 template<bool big_endian
>
450 const Target::Target_info Target_arm
<big_endian
>::arm_info
=
453 big_endian
, // is_big_endian
454 elfcpp::EM_ARM
, // machine_code
455 false, // has_make_symbol
456 false, // has_resolve
457 false, // has_code_fill
458 true, // is_default_stack_executable
460 "/usr/lib/libc.so.1", // dynamic_linker
461 0x8000, // default_text_segment_address
462 0x1000, // abi_pagesize (overridable by -z max-page-size)
463 0x1000, // common_pagesize (overridable by -z common-page-size)
464 elfcpp::SHN_UNDEF
, // small_common_shndx
465 elfcpp::SHN_UNDEF
, // large_common_shndx
466 0, // small_common_section_flags
467 0 // large_common_section_flags
470 // Arm relocate functions class
473 template<bool big_endian
>
474 class Arm_relocate_functions
: public Relocate_functions
<32, big_endian
>
479 STATUS_OKAY
, // No error during relocation.
480 STATUS_OVERFLOW
, // Relocation oveflow.
481 STATUS_BAD_RELOC
// Relocation cannot be applied.
485 typedef Relocate_functions
<32, big_endian
> Base
;
486 typedef Arm_relocate_functions
<big_endian
> This
;
488 // Get an symbol value of *PSYMVAL with an ADDEND. This is a wrapper
489 // to Symbol_value::value(). If HAS_THUMB_BIT is true, that LSB is used
490 // to distinguish ARM and THUMB functions and it is treated specially.
491 static inline Symbol_value
<32>::Value
492 arm_symbol_value (const Sized_relobj
<32, big_endian
> *object
,
493 const Symbol_value
<32>* psymval
,
494 Symbol_value
<32>::Value addend
,
497 typedef Symbol_value
<32>::Value Valtype
;
501 Valtype raw
= psymval
->value(object
, 0);
502 Valtype thumb_bit
= raw
& 1;
503 return ((raw
& ~((Valtype
) 1)) + addend
) | thumb_bit
;
506 return psymval
->value(object
, addend
);
509 // FIXME: This probably only works for Android on ARM v5te. We should
510 // following GNU ld for the general case.
511 template<unsigned r_type
>
512 static inline typename
This::Status
513 arm_branch_common(unsigned char *view
,
514 const Sized_relobj
<32, big_endian
>* object
,
515 const Symbol_value
<32>* psymval
,
516 elfcpp::Elf_types
<32>::Elf_Addr address
,
519 typedef typename
elfcpp::Swap
<32, big_endian
>::Valtype Valtype
;
520 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
521 Valtype val
= elfcpp::Swap
<32, big_endian
>::readval(wv
);
523 bool insn_is_b
= (((val
>> 28) & 0xf) <= 0xe)
524 && ((val
& 0x0f000000UL
) == 0x0a000000UL
);
525 bool insn_is_uncond_bl
= (val
& 0xff000000UL
) == 0xeb000000UL
;
526 bool insn_is_cond_bl
= (((val
>> 28) & 0xf) < 0xe)
527 && ((val
& 0x0f000000UL
) == 0x0b000000UL
);
528 bool insn_is_blx
= (val
& 0xfe000000UL
) == 0xfa000000UL
;
529 bool insn_is_any_branch
= (val
& 0x0e000000UL
) == 0x0a000000UL
;
531 if (r_type
== elfcpp::R_ARM_CALL
)
533 if (!insn_is_uncond_bl
&& !insn_is_blx
)
534 return This::STATUS_BAD_RELOC
;
536 else if (r_type
== elfcpp::R_ARM_JUMP24
)
538 if (!insn_is_b
&& !insn_is_cond_bl
)
539 return This::STATUS_BAD_RELOC
;
541 else if (r_type
== elfcpp::R_ARM_PLT32
)
543 if (!insn_is_any_branch
)
544 return This::STATUS_BAD_RELOC
;
549 Valtype addend
= utils::sign_extend
<26>(val
<< 2);
550 Valtype x
= (This::arm_symbol_value(object
, psymval
, addend
, has_thumb_bit
)
553 // If target has thumb bit set, we need to either turn the BL
554 // into a BLX (for ARMv5 or above) or generate a stub.
558 if (insn_is_uncond_bl
)
559 val
= (val
& 0xffffff) | 0xfa000000 | ((x
& 2) << 23);
561 return This::STATUS_BAD_RELOC
;
564 gold_assert(!insn_is_blx
);
566 val
= utils::bit_select(val
, (x
>> 2), 0xffffffUL
);
567 elfcpp::Swap
<32, big_endian
>::writeval(wv
, val
);
568 return (utils::has_overflow
<26>(x
)
569 ? This::STATUS_OVERFLOW
: This::STATUS_OKAY
);
575 static inline typename
This::Status
576 abs8(unsigned char *view
,
577 const Sized_relobj
<32, big_endian
>* object
,
578 const Symbol_value
<32>* psymval
, bool has_thumb_bit
)
580 typedef typename
elfcpp::Swap
<8, big_endian
>::Valtype Valtype
;
581 typedef typename
elfcpp::Swap
<32, big_endian
>::Valtype Reltype
;
582 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
583 Valtype val
= elfcpp::Swap
<8, big_endian
>::readval(wv
);
584 Reltype addend
= utils::sign_extend
<8>(val
);
585 Reltype x
= This::arm_symbol_value(object
, psymval
, addend
, has_thumb_bit
);
586 val
= utils::bit_select(val
, x
, 0xffU
);
587 elfcpp::Swap
<8, big_endian
>::writeval(wv
, val
);
588 return (utils::has_signed_unsigned_overflow
<8>(x
)
589 ? This::STATUS_OVERFLOW
590 : This::STATUS_OKAY
);
593 // R_ARM_ABS32: (S + A) | T
594 static inline typename
This::Status
595 abs32(unsigned char *view
,
596 const Sized_relobj
<32, big_endian
>* object
,
597 const Symbol_value
<32>* psymval
,
600 typedef typename
elfcpp::Swap
<32, big_endian
>::Valtype Valtype
;
601 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
602 Valtype addend
= elfcpp::Swap
<32, big_endian
>::readval(wv
);
603 Valtype x
= This::arm_symbol_value(object
, psymval
, addend
, has_thumb_bit
);
604 elfcpp::Swap
<32, big_endian
>::writeval(wv
, x
);
605 return This::STATUS_OKAY
;
608 // R_ARM_REL32: (S + A) | T - P
609 static inline typename
This::Status
610 rel32(unsigned char *view
,
611 const Sized_relobj
<32, big_endian
>* object
,
612 const Symbol_value
<32>* psymval
,
613 elfcpp::Elf_types
<32>::Elf_Addr address
,
616 typedef typename
elfcpp::Swap
<32, big_endian
>::Valtype Valtype
;
617 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
618 Valtype addend
= elfcpp::Swap
<32, big_endian
>::readval(wv
);
619 Valtype x
= (This::arm_symbol_value(object
, psymval
, addend
, has_thumb_bit
)
621 elfcpp::Swap
<32, big_endian
>::writeval(wv
, x
);
622 return This::STATUS_OKAY
;
625 // R_ARM_THM_CALL: (S + A) | T - P
626 static inline typename
This::Status
627 thm_call(unsigned char *view
,
628 const Sized_relobj
<32, big_endian
>* object
,
629 const Symbol_value
<32>* psymval
,
630 elfcpp::Elf_types
<32>::Elf_Addr address
,
633 // A thumb call consists of two instructions.
634 typedef typename
elfcpp::Swap
<16, big_endian
>::Valtype Valtype
;
635 typedef typename
elfcpp::Swap
<32, big_endian
>::Valtype Reltype
;
636 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
637 Valtype hi
= elfcpp::Swap
<16, big_endian
>::readval(wv
);
638 Valtype lo
= elfcpp::Swap
<16, big_endian
>::readval(wv
+ 1);
639 // Must be a BL instruction. lo == 11111xxxxxxxxxxx.
640 gold_assert((lo
& 0xf800) == 0xf800);
641 Reltype addend
= utils::sign_extend
<23>(((hi
& 0x7ff) << 12)
642 | ((lo
& 0x7ff) << 1));
643 Reltype x
= (This::arm_symbol_value(object
, psymval
, addend
, has_thumb_bit
)
646 // If target has no thumb bit set, we need to either turn the BL
647 // into a BLX (for ARMv5 or above) or generate a stub.
650 // This only works for ARMv5 and above with interworking enabled.
653 hi
= utils::bit_select(hi
, (x
>> 12), 0x7ffU
);
654 lo
= utils::bit_select(lo
, (x
>> 1), 0x7ffU
);
655 elfcpp::Swap
<16, big_endian
>::writeval(wv
, hi
);
656 elfcpp::Swap
<16, big_endian
>::writeval(wv
+ 1, lo
);
657 return (utils::has_overflow
<23>(x
)
658 ? This::STATUS_OVERFLOW
659 : This::STATUS_OKAY
);
662 // R_ARM_BASE_PREL: B(S) + A - P
663 static inline typename
This::Status
664 base_prel(unsigned char* view
,
665 elfcpp::Elf_types
<32>::Elf_Addr origin
,
666 elfcpp::Elf_types
<32>::Elf_Addr address
)
668 Base::rel32(view
, origin
- address
);
672 // R_ARM_GOT_BREL: GOT(S) + A - GOT_ORG
673 static inline typename
This::Status
674 got_brel(unsigned char* view
,
675 typename
elfcpp::Swap
<32, big_endian
>::Valtype got_offset
)
677 Base::rel32(view
, got_offset
);
678 return This::STATUS_OKAY
;
681 // R_ARM_PLT32: (S + A) | T - P
682 static inline typename
This::Status
683 plt32(unsigned char *view
,
684 const Sized_relobj
<32, big_endian
>* object
,
685 const Symbol_value
<32>* psymval
,
686 elfcpp::Elf_types
<32>::Elf_Addr address
,
689 return arm_branch_common
<elfcpp::R_ARM_PLT32
>(view
, object
, psymval
,
690 address
, has_thumb_bit
);
693 // R_ARM_CALL: (S + A) | T - P
694 static inline typename
This::Status
695 call(unsigned char *view
,
696 const Sized_relobj
<32, big_endian
>* object
,
697 const Symbol_value
<32>* psymval
,
698 elfcpp::Elf_types
<32>::Elf_Addr address
,
701 return arm_branch_common
<elfcpp::R_ARM_CALL
>(view
, object
, psymval
,
702 address
, has_thumb_bit
);
705 // R_ARM_JUMP24: (S + A) | T - P
706 static inline typename
This::Status
707 jump24(unsigned char *view
,
708 const Sized_relobj
<32, big_endian
>* object
,
709 const Symbol_value
<32>* psymval
,
710 elfcpp::Elf_types
<32>::Elf_Addr address
,
713 return arm_branch_common
<elfcpp::R_ARM_JUMP24
>(view
, object
, psymval
,
714 address
, has_thumb_bit
);
717 // R_ARM_PREL: (S + A) | T - P
718 static inline typename
This::Status
719 prel31(unsigned char *view
,
720 const Sized_relobj
<32, big_endian
>* object
,
721 const Symbol_value
<32>* psymval
,
722 elfcpp::Elf_types
<32>::Elf_Addr address
,
725 typedef typename
elfcpp::Swap
<32, big_endian
>::Valtype Valtype
;
726 Valtype
* wv
= reinterpret_cast<Valtype
*>(view
);
727 Valtype val
= elfcpp::Swap
<32, big_endian
>::readval(wv
);
728 Valtype addend
= utils::sign_extend
<31>(val
);
729 Valtype x
= (This::arm_symbol_value(object
, psymval
, addend
, has_thumb_bit
)
731 val
= utils::bit_select(val
, x
, 0x7fffffffU
);
732 elfcpp::Swap
<32, big_endian
>::writeval(wv
, val
);
733 return (utils::has_overflow
<31>(x
) ?
734 This::STATUS_OVERFLOW
: This::STATUS_OKAY
);
738 // Get the GOT section, creating it if necessary.
740 template<bool big_endian
>
741 Output_data_got
<32, big_endian
>*
742 Target_arm
<big_endian
>::got_section(Symbol_table
* symtab
, Layout
* layout
)
744 if (this->got_
== NULL
)
746 gold_assert(symtab
!= NULL
&& layout
!= NULL
);
748 this->got_
= new Output_data_got
<32, big_endian
>();
751 os
= layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
753 | elfcpp::SHF_WRITE
),
757 // The old GNU linker creates a .got.plt section. We just
758 // create another set of data in the .got section. Note that we
759 // always create a PLT if we create a GOT, although the PLT
761 this->got_plt_
= new Output_data_space(4, "** GOT PLT");
762 os
= layout
->add_output_section_data(".got", elfcpp::SHT_PROGBITS
,
764 | elfcpp::SHF_WRITE
),
768 // The first three entries are reserved.
769 this->got_plt_
->set_current_data_size(3 * 4);
771 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
772 symtab
->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL
,
774 0, 0, elfcpp::STT_OBJECT
,
776 elfcpp::STV_HIDDEN
, 0,
782 // Get the dynamic reloc section, creating it if necessary.
784 template<bool big_endian
>
785 typename Target_arm
<big_endian
>::Reloc_section
*
786 Target_arm
<big_endian
>::rel_dyn_section(Layout
* layout
)
788 if (this->rel_dyn_
== NULL
)
790 gold_assert(layout
!= NULL
);
791 this->rel_dyn_
= new Reloc_section(parameters
->options().combreloc());
792 layout
->add_output_section_data(".rel.dyn", elfcpp::SHT_REL
,
793 elfcpp::SHF_ALLOC
, this->rel_dyn_
);
795 return this->rel_dyn_
;
798 // A class to handle the PLT data.
800 template<bool big_endian
>
801 class Output_data_plt_arm
: public Output_section_data
804 typedef Output_data_reloc
<elfcpp::SHT_REL
, true, 32, big_endian
>
807 Output_data_plt_arm(Layout
*, Output_data_space
*);
809 // Add an entry to the PLT.
811 add_entry(Symbol
* gsym
);
813 // Return the .rel.plt section data.
816 { return this->rel_
; }
820 do_adjust_output_section(Output_section
* os
);
822 // Write to a map file.
824 do_print_to_mapfile(Mapfile
* mapfile
) const
825 { mapfile
->print_output_data(this, _("** PLT")); }
828 // Template for the first PLT entry.
829 static const uint32_t first_plt_entry
[5];
831 // Template for subsequent PLT entries.
832 static const uint32_t plt_entry
[3];
834 // Set the final size.
836 set_final_data_size()
838 this->set_data_size(sizeof(first_plt_entry
)
839 + this->count_
* sizeof(plt_entry
));
842 // Write out the PLT data.
844 do_write(Output_file
*);
846 // The reloc section.
848 // The .got.plt section.
849 Output_data_space
* got_plt_
;
850 // The number of PLT entries.
854 // Create the PLT section. The ordinary .got section is an argument,
855 // since we need to refer to the start. We also create our own .got
856 // section just for PLT entries.
858 template<bool big_endian
>
859 Output_data_plt_arm
<big_endian
>::Output_data_plt_arm(Layout
* layout
,
860 Output_data_space
* got_plt
)
861 : Output_section_data(4), got_plt_(got_plt
), count_(0)
863 this->rel_
= new Reloc_section(false);
864 layout
->add_output_section_data(".rel.plt", elfcpp::SHT_REL
,
865 elfcpp::SHF_ALLOC
, this->rel_
);
868 template<bool big_endian
>
870 Output_data_plt_arm
<big_endian
>::do_adjust_output_section(Output_section
* os
)
875 // Add an entry to the PLT.
877 template<bool big_endian
>
879 Output_data_plt_arm
<big_endian
>::add_entry(Symbol
* gsym
)
881 gold_assert(!gsym
->has_plt_offset());
883 // Note that when setting the PLT offset we skip the initial
884 // reserved PLT entry.
885 gsym
->set_plt_offset((this->count_
) * sizeof(plt_entry
)
886 + sizeof(first_plt_entry
));
890 section_offset_type got_offset
= this->got_plt_
->current_data_size();
892 // Every PLT entry needs a GOT entry which points back to the PLT
893 // entry (this will be changed by the dynamic linker, normally
894 // lazily when the function is called).
895 this->got_plt_
->set_current_data_size(got_offset
+ 4);
897 // Every PLT entry needs a reloc.
898 gsym
->set_needs_dynsym_entry();
899 this->rel_
->add_global(gsym
, elfcpp::R_ARM_JUMP_SLOT
, this->got_plt_
,
902 // Note that we don't need to save the symbol. The contents of the
903 // PLT are independent of which symbols are used. The symbols only
904 // appear in the relocations.
908 // FIXME: This is not very flexible. Right now this has only been tested
909 // on armv5te. If we are to support additional architecture features like
910 // Thumb-2 or BE8, we need to make this more flexible like GNU ld.
912 // The first entry in the PLT.
913 template<bool big_endian
>
914 const uint32_t Output_data_plt_arm
<big_endian
>::first_plt_entry
[5] =
916 0xe52de004, // str lr, [sp, #-4]!
917 0xe59fe004, // ldr lr, [pc, #4]
918 0xe08fe00e, // add lr, pc, lr
919 0xe5bef008, // ldr pc, [lr, #8]!
920 0x00000000, // &GOT[0] - .
923 // Subsequent entries in the PLT.
925 template<bool big_endian
>
926 const uint32_t Output_data_plt_arm
<big_endian
>::plt_entry
[3] =
928 0xe28fc600, // add ip, pc, #0xNN00000
929 0xe28cca00, // add ip, ip, #0xNN000
930 0xe5bcf000, // ldr pc, [ip, #0xNNN]!
933 // Write out the PLT. This uses the hand-coded instructions above,
934 // and adjusts them as needed. This is all specified by the arm ELF
935 // Processor Supplement.
937 template<bool big_endian
>
939 Output_data_plt_arm
<big_endian
>::do_write(Output_file
* of
)
941 const off_t offset
= this->offset();
942 const section_size_type oview_size
=
943 convert_to_section_size_type(this->data_size());
944 unsigned char* const oview
= of
->get_output_view(offset
, oview_size
);
946 const off_t got_file_offset
= this->got_plt_
->offset();
947 const section_size_type got_size
=
948 convert_to_section_size_type(this->got_plt_
->data_size());
949 unsigned char* const got_view
= of
->get_output_view(got_file_offset
,
951 unsigned char* pov
= oview
;
953 elfcpp::Elf_types
<32>::Elf_Addr plt_address
= this->address();
954 elfcpp::Elf_types
<32>::Elf_Addr got_address
= this->got_plt_
->address();
956 // Write first PLT entry. All but the last word are constants.
957 const size_t num_first_plt_words
= (sizeof(first_plt_entry
)
958 / sizeof(plt_entry
[0]));
959 for (size_t i
= 0; i
< num_first_plt_words
- 1; i
++)
960 elfcpp::Swap
<32, big_endian
>::writeval(pov
+ i
* 4, first_plt_entry
[i
]);
961 // Last word in first PLT entry is &GOT[0] - .
962 elfcpp::Swap
<32, big_endian
>::writeval(pov
+ 16,
963 got_address
- (plt_address
+ 16));
964 pov
+= sizeof(first_plt_entry
);
966 unsigned char* got_pov
= got_view
;
968 memset(got_pov
, 0, 12);
971 const int rel_size
= elfcpp::Elf_sizes
<32>::rel_size
;
972 unsigned int plt_offset
= sizeof(first_plt_entry
);
973 unsigned int plt_rel_offset
= 0;
974 unsigned int got_offset
= 12;
975 const unsigned int count
= this->count_
;
976 for (unsigned int i
= 0;
979 pov
+= sizeof(plt_entry
),
981 plt_offset
+= sizeof(plt_entry
),
982 plt_rel_offset
+= rel_size
,
985 // Set and adjust the PLT entry itself.
986 int32_t offset
= ((got_address
+ got_offset
)
987 - (plt_address
+ plt_offset
+ 8));
989 gold_assert(offset
>= 0 && offset
< 0x0fffffff);
990 uint32_t plt_insn0
= plt_entry
[0] | ((offset
>> 20) & 0xff);
991 elfcpp::Swap
<32, big_endian
>::writeval(pov
, plt_insn0
);
992 uint32_t plt_insn1
= plt_entry
[1] | ((offset
>> 12) & 0xff);
993 elfcpp::Swap
<32, big_endian
>::writeval(pov
+ 4, plt_insn1
);
994 uint32_t plt_insn2
= plt_entry
[2] | (offset
& 0xfff);
995 elfcpp::Swap
<32, big_endian
>::writeval(pov
+ 8, plt_insn2
);
997 // Set the entry in the GOT.
998 elfcpp::Swap
<32, big_endian
>::writeval(got_pov
, plt_address
);
1001 gold_assert(static_cast<section_size_type
>(pov
- oview
) == oview_size
);
1002 gold_assert(static_cast<section_size_type
>(got_pov
- got_view
) == got_size
);
1004 of
->write_output_view(offset
, oview_size
, oview
);
1005 of
->write_output_view(got_file_offset
, got_size
, got_view
);
1008 // Create a PLT entry for a global symbol.
1010 template<bool big_endian
>
1012 Target_arm
<big_endian
>::make_plt_entry(Symbol_table
* symtab
, Layout
* layout
,
1015 if (gsym
->has_plt_offset())
1018 if (this->plt_
== NULL
)
1020 // Create the GOT sections first.
1021 this->got_section(symtab
, layout
);
1023 this->plt_
= new Output_data_plt_arm
<big_endian
>(layout
, this->got_plt_
);
1024 layout
->add_output_section_data(".plt", elfcpp::SHT_PROGBITS
,
1026 | elfcpp::SHF_EXECINSTR
),
1029 this->plt_
->add_entry(gsym
);
1032 // Report an unsupported relocation against a local symbol.
1034 template<bool big_endian
>
1036 Target_arm
<big_endian
>::Scan::unsupported_reloc_local(
1037 Sized_relobj
<32, big_endian
>* object
,
1038 unsigned int r_type
)
1040 gold_error(_("%s: unsupported reloc %u against local symbol"),
1041 object
->name().c_str(), r_type
);
1044 // We are about to emit a dynamic relocation of type R_TYPE. If the
1045 // dynamic linker does not support it, issue an error. The GNU linker
1046 // only issues a non-PIC error for an allocated read-only section.
1047 // Here we know the section is allocated, but we don't know that it is
1048 // read-only. But we check for all the relocation types which the
1049 // glibc dynamic linker supports, so it seems appropriate to issue an
1050 // error even if the section is not read-only.
1052 template<bool big_endian
>
1054 Target_arm
<big_endian
>::Scan::check_non_pic(Relobj
* object
,
1055 unsigned int r_type
)
1059 // These are the relocation types supported by glibc for ARM.
1060 case elfcpp::R_ARM_RELATIVE
:
1061 case elfcpp::R_ARM_COPY
:
1062 case elfcpp::R_ARM_GLOB_DAT
:
1063 case elfcpp::R_ARM_JUMP_SLOT
:
1064 case elfcpp::R_ARM_ABS32
:
1065 case elfcpp::R_ARM_PC24
:
1066 // FIXME: The following 3 types are not supported by Android's dynamic
1068 case elfcpp::R_ARM_TLS_DTPMOD32
:
1069 case elfcpp::R_ARM_TLS_DTPOFF32
:
1070 case elfcpp::R_ARM_TLS_TPOFF32
:
1074 // This prevents us from issuing more than one error per reloc
1075 // section. But we can still wind up issuing more than one
1076 // error per object file.
1077 if (this->issued_non_pic_error_
)
1079 object
->error(_("requires unsupported dynamic reloc; "
1080 "recompile with -fPIC"));
1081 this->issued_non_pic_error_
= true;
1084 case elfcpp::R_ARM_NONE
:
1089 // Scan a relocation for a local symbol.
1090 // FIXME: This only handles a subset of relocation types used by Android
1091 // on ARM v5te devices.
1093 template<bool big_endian
>
1095 Target_arm
<big_endian
>::Scan::local(const General_options
&,
1096 Symbol_table
* symtab
,
1099 Sized_relobj
<32, big_endian
>* object
,
1100 unsigned int data_shndx
,
1101 Output_section
* output_section
,
1102 const elfcpp::Rel
<32, big_endian
>& reloc
,
1103 unsigned int r_type
,
1104 const elfcpp::Sym
<32, big_endian
>&)
1106 r_type
= get_real_reloc_type(r_type
);
1109 case elfcpp::R_ARM_NONE
:
1112 case elfcpp::R_ARM_ABS8
:
1113 if (parameters
->options().output_is_position_independent())
1115 // FIXME: Create a dynamic relocation for this location.
1116 gold_error(_("%s: gold bug: need dynamic ABS8 reloc"),
1117 object
->name().c_str());
1121 case elfcpp::R_ARM_ABS32
:
1122 // If building a shared library (or a position-independent
1123 // executable), we need to create a dynamic relocation for
1124 // this location. The relocation applied at link time will
1125 // apply the link-time value, so we flag the location with
1126 // an R_ARM_RELATIVE relocation so the dynamic loader can
1127 // relocate it easily.
1128 if (parameters
->options().output_is_position_independent())
1130 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1131 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(reloc
.get_r_info());
1132 // If we are to add more other reloc types than R_ARM_ABS32,
1133 // we need to add check_non_pic(object, r_type) here.
1134 rel_dyn
->add_local_relative(object
, r_sym
, elfcpp::R_ARM_RELATIVE
,
1135 output_section
, data_shndx
,
1136 reloc
.get_r_offset());
1140 case elfcpp::R_ARM_REL32
:
1141 case elfcpp::R_ARM_THM_CALL
:
1142 case elfcpp::R_ARM_CALL
:
1143 case elfcpp::R_ARM_PREL31
:
1144 case elfcpp::R_ARM_JUMP24
:
1145 case elfcpp::R_ARM_PLT32
:
1148 case elfcpp::R_ARM_GOTOFF32
:
1149 // We need a GOT section:
1150 target
->got_section(symtab
, layout
);
1153 case elfcpp::R_ARM_BASE_PREL
:
1154 // FIXME: What about this?
1157 case elfcpp::R_ARM_GOT_BREL
:
1159 // The symbol requires a GOT entry.
1160 Output_data_got
<32, big_endian
>* got
=
1161 target
->got_section(symtab
, layout
);
1162 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(reloc
.get_r_info());
1163 if (got
->add_local(object
, r_sym
, GOT_TYPE_STANDARD
))
1165 // If we are generating a shared object, we need to add a
1166 // dynamic RELATIVE relocation for this symbol's GOT entry.
1167 if (parameters
->options().output_is_position_independent())
1169 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1170 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(reloc
.get_r_info());
1171 rel_dyn
->add_local_relative(
1172 object
, r_sym
, elfcpp::R_ARM_RELATIVE
, got
,
1173 object
->local_got_offset(r_sym
, GOT_TYPE_STANDARD
));
1179 case elfcpp::R_ARM_TARGET1
:
1180 // This should have been mapped to another type already.
1182 case elfcpp::R_ARM_COPY
:
1183 case elfcpp::R_ARM_GLOB_DAT
:
1184 case elfcpp::R_ARM_JUMP_SLOT
:
1185 case elfcpp::R_ARM_RELATIVE
:
1186 // These are relocations which should only be seen by the
1187 // dynamic linker, and should never be seen here.
1188 gold_error(_("%s: unexpected reloc %u in object file"),
1189 object
->name().c_str(), r_type
);
1193 unsupported_reloc_local(object
, r_type
);
1198 // Report an unsupported relocation against a global symbol.
1200 template<bool big_endian
>
1202 Target_arm
<big_endian
>::Scan::unsupported_reloc_global(
1203 Sized_relobj
<32, big_endian
>* object
,
1204 unsigned int r_type
,
1207 gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1208 object
->name().c_str(), r_type
, gsym
->demangled_name().c_str());
1211 // Scan a relocation for a global symbol.
1212 // FIXME: This only handles a subset of relocation types used by Android
1213 // on ARM v5te devices.
1215 template<bool big_endian
>
1217 Target_arm
<big_endian
>::Scan::global(const General_options
&,
1218 Symbol_table
* symtab
,
1221 Sized_relobj
<32, big_endian
>* object
,
1222 unsigned int data_shndx
,
1223 Output_section
* output_section
,
1224 const elfcpp::Rel
<32, big_endian
>& reloc
,
1225 unsigned int r_type
,
1228 r_type
= get_real_reloc_type(r_type
);
1231 case elfcpp::R_ARM_NONE
:
1234 case elfcpp::R_ARM_ABS8
:
1235 // Make a dynamic relocation if necessary.
1236 if (gsym
->needs_dynamic_reloc(Symbol::ABSOLUTE_REF
))
1238 // FIXME: Create a dynamic relocation for this location.
1239 gold_error(_("%s: gold bug: need dynamic ABS8 reloc for %s"),
1240 object
->name().c_str(), gsym
->demangled_name().c_str());
1244 case elfcpp::R_ARM_ABS32
:
1246 // Make a dynamic relocation if necessary.
1247 if (gsym
->needs_dynamic_reloc(Symbol::ABSOLUTE_REF
))
1249 if (target
->may_need_copy_reloc(gsym
))
1251 target
->copy_reloc(symtab
, layout
, object
,
1252 data_shndx
, output_section
, gsym
, reloc
);
1254 else if (gsym
->can_use_relative_reloc(false))
1256 // If we are to add more other reloc types than R_ARM_ABS32,
1257 // we need to add check_non_pic(object, r_type) here.
1258 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1259 rel_dyn
->add_global_relative(gsym
, elfcpp::R_ARM_RELATIVE
,
1260 output_section
, object
,
1261 data_shndx
, reloc
.get_r_offset());
1265 // If we are to add more other reloc types than R_ARM_ABS32,
1266 // we need to add check_non_pic(object, r_type) here.
1267 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1268 rel_dyn
->add_global(gsym
, r_type
, output_section
, object
,
1269 data_shndx
, reloc
.get_r_offset());
1275 case elfcpp::R_ARM_REL32
:
1276 case elfcpp::R_ARM_PREL31
:
1278 // Make a dynamic relocation if necessary.
1279 int flags
= Symbol::NON_PIC_REF
;
1280 if (gsym
->needs_dynamic_reloc(flags
))
1282 if (target
->may_need_copy_reloc(gsym
))
1284 target
->copy_reloc(symtab
, layout
, object
,
1285 data_shndx
, output_section
, gsym
, reloc
);
1289 check_non_pic(object
, r_type
);
1290 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1291 rel_dyn
->add_global(gsym
, r_type
, output_section
, object
,
1292 data_shndx
, reloc
.get_r_offset());
1298 case elfcpp::R_ARM_JUMP24
:
1299 case elfcpp::R_ARM_THM_CALL
:
1300 case elfcpp::R_ARM_CALL
:
1302 if (Target_arm
<big_endian
>::Scan::symbol_needs_plt_entry(gsym
))
1303 target
->make_plt_entry(symtab
, layout
, gsym
);
1304 // Make a dynamic relocation if necessary.
1305 int flags
= Symbol::NON_PIC_REF
;
1306 if (gsym
->type() == elfcpp::STT_FUNC
1307 || gsym
->type() == elfcpp::STT_ARM_TFUNC
)
1308 flags
|= Symbol::FUNCTION_CALL
;
1309 if (gsym
->needs_dynamic_reloc(flags
))
1311 if (target
->may_need_copy_reloc(gsym
))
1313 target
->copy_reloc(symtab
, layout
, object
,
1314 data_shndx
, output_section
, gsym
,
1319 check_non_pic(object
, r_type
);
1320 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1321 rel_dyn
->add_global(gsym
, r_type
, output_section
, object
,
1322 data_shndx
, reloc
.get_r_offset());
1328 case elfcpp::R_ARM_PLT32
:
1329 // If the symbol is fully resolved, this is just a relative
1330 // local reloc. Otherwise we need a PLT entry.
1331 if (gsym
->final_value_is_known())
1333 // If building a shared library, we can also skip the PLT entry
1334 // if the symbol is defined in the output file and is protected
1336 if (gsym
->is_defined()
1337 && !gsym
->is_from_dynobj()
1338 && !gsym
->is_preemptible())
1340 target
->make_plt_entry(symtab
, layout
, gsym
);
1343 case elfcpp::R_ARM_GOTOFF32
:
1344 // We need a GOT section.
1345 target
->got_section(symtab
, layout
);
1348 case elfcpp::R_ARM_BASE_PREL
:
1349 // FIXME: What about this?
1352 case elfcpp::R_ARM_GOT_BREL
:
1354 // The symbol requires a GOT entry.
1355 Output_data_got
<32, big_endian
>* got
=
1356 target
->got_section(symtab
, layout
);
1357 if (gsym
->final_value_is_known())
1358 got
->add_global(gsym
, GOT_TYPE_STANDARD
);
1361 // If this symbol is not fully resolved, we need to add a
1362 // GOT entry with a dynamic relocation.
1363 Reloc_section
* rel_dyn
= target
->rel_dyn_section(layout
);
1364 if (gsym
->is_from_dynobj()
1365 || gsym
->is_undefined()
1366 || gsym
->is_preemptible())
1367 got
->add_global_with_rel(gsym
, GOT_TYPE_STANDARD
,
1368 rel_dyn
, elfcpp::R_ARM_GLOB_DAT
);
1371 if (got
->add_global(gsym
, GOT_TYPE_STANDARD
))
1372 rel_dyn
->add_global_relative(
1373 gsym
, elfcpp::R_ARM_RELATIVE
, got
,
1374 gsym
->got_offset(GOT_TYPE_STANDARD
));
1380 case elfcpp::R_ARM_TARGET1
:
1381 // This should have been mapped to another type already.
1383 case elfcpp::R_ARM_COPY
:
1384 case elfcpp::R_ARM_GLOB_DAT
:
1385 case elfcpp::R_ARM_JUMP_SLOT
:
1386 case elfcpp::R_ARM_RELATIVE
:
1387 // These are relocations which should only be seen by the
1388 // dynamic linker, and should never be seen here.
1389 gold_error(_("%s: unexpected reloc %u in object file"),
1390 object
->name().c_str(), r_type
);
1394 unsupported_reloc_global(object
, r_type
, gsym
);
1399 // Process relocations for gc.
1401 template<bool big_endian
>
1403 Target_arm
<big_endian
>::gc_process_relocs(const General_options
& options
,
1404 Symbol_table
* symtab
,
1406 Sized_relobj
<32, big_endian
>* object
,
1407 unsigned int data_shndx
,
1409 const unsigned char* prelocs
,
1411 Output_section
* output_section
,
1412 bool needs_special_offset_handling
,
1413 size_t local_symbol_count
,
1414 const unsigned char* plocal_symbols
)
1416 typedef Target_arm
<big_endian
> Arm
;
1417 typedef typename Target_arm
<big_endian
>::Scan Scan
;
1419 gold::gc_process_relocs
<32, big_endian
, Arm
, elfcpp::SHT_REL
, Scan
>(
1429 needs_special_offset_handling
,
1434 // Scan relocations for a section.
1436 template<bool big_endian
>
1438 Target_arm
<big_endian
>::scan_relocs(const General_options
& options
,
1439 Symbol_table
* symtab
,
1441 Sized_relobj
<32, big_endian
>* object
,
1442 unsigned int data_shndx
,
1443 unsigned int sh_type
,
1444 const unsigned char* prelocs
,
1446 Output_section
* output_section
,
1447 bool needs_special_offset_handling
,
1448 size_t local_symbol_count
,
1449 const unsigned char* plocal_symbols
)
1451 typedef typename Target_arm
<big_endian
>::Scan Scan
;
1452 if (sh_type
== elfcpp::SHT_RELA
)
1454 gold_error(_("%s: unsupported RELA reloc section"),
1455 object
->name().c_str());
1459 gold::scan_relocs
<32, big_endian
, Target_arm
, elfcpp::SHT_REL
, Scan
>(
1469 needs_special_offset_handling
,
1474 // Finalize the sections.
1476 template<bool big_endian
>
1478 Target_arm
<big_endian
>::do_finalize_sections(Layout
* layout
)
1480 // Fill in some more dynamic tags.
1481 Output_data_dynamic
* const odyn
= layout
->dynamic_data();
1484 if (this->got_plt_
!= NULL
)
1485 odyn
->add_section_address(elfcpp::DT_PLTGOT
, this->got_plt_
);
1487 if (this->plt_
!= NULL
)
1489 const Output_data
* od
= this->plt_
->rel_plt();
1490 odyn
->add_section_size(elfcpp::DT_PLTRELSZ
, od
);
1491 odyn
->add_section_address(elfcpp::DT_JMPREL
, od
);
1492 odyn
->add_constant(elfcpp::DT_PLTREL
, elfcpp::DT_REL
);
1495 if (this->rel_dyn_
!= NULL
)
1497 const Output_data
* od
= this->rel_dyn_
;
1498 odyn
->add_section_address(elfcpp::DT_REL
, od
);
1499 odyn
->add_section_size(elfcpp::DT_RELSZ
, od
);
1500 odyn
->add_constant(elfcpp::DT_RELENT
,
1501 elfcpp::Elf_sizes
<32>::rel_size
);
1504 if (!parameters
->options().shared())
1506 // The value of the DT_DEBUG tag is filled in by the dynamic
1507 // linker at run time, and used by the debugger.
1508 odyn
->add_constant(elfcpp::DT_DEBUG
, 0);
1512 // Emit any relocs we saved in an attempt to avoid generating COPY
1514 if (this->copy_relocs_
.any_saved_relocs())
1515 this->copy_relocs_
.emit(this->rel_dyn_section(layout
));
1517 // For the ARM target, we need to add a PT_ARM_EXIDX segment for
1518 // the .ARM.exidx section.
1519 if (!layout
->script_options()->saw_phdrs_clause()
1520 && !parameters
->options().relocatable())
1522 Output_section
* exidx_section
=
1523 layout
->find_output_section(".ARM.exidx");
1525 if (exidx_section
!= NULL
1526 && exidx_section
->type() == elfcpp::SHT_ARM_EXIDX
)
1528 gold_assert(layout
->find_output_segment(elfcpp::PT_ARM_EXIDX
, 0, 0)
1530 Output_segment
* exidx_segment
=
1531 layout
->make_output_segment(elfcpp::PT_ARM_EXIDX
, elfcpp::PF_R
);
1532 exidx_segment
->add_output_section(exidx_section
, elfcpp::PF_R
);
1537 // Return whether a direct absolute static relocation needs to be applied.
1538 // In cases where Scan::local() or Scan::global() has created
1539 // a dynamic relocation other than R_ARM_RELATIVE, the addend
1540 // of the relocation is carried in the data, and we must not
1541 // apply the static relocation.
1543 template<bool big_endian
>
1545 Target_arm
<big_endian
>::Relocate::should_apply_static_reloc(
1546 const Sized_symbol
<32>* gsym
,
1549 Output_section
* output_section
)
1551 // If the output section is not allocated, then we didn't call
1552 // scan_relocs, we didn't create a dynamic reloc, and we must apply
1554 if ((output_section
->flags() & elfcpp::SHF_ALLOC
) == 0)
1557 // For local symbols, we will have created a non-RELATIVE dynamic
1558 // relocation only if (a) the output is position independent,
1559 // (b) the relocation is absolute (not pc- or segment-relative), and
1560 // (c) the relocation is not 32 bits wide.
1562 return !(parameters
->options().output_is_position_independent()
1563 && (ref_flags
& Symbol::ABSOLUTE_REF
)
1566 // For global symbols, we use the same helper routines used in the
1567 // scan pass. If we did not create a dynamic relocation, or if we
1568 // created a RELATIVE dynamic relocation, we should apply the static
1570 bool has_dyn
= gsym
->needs_dynamic_reloc(ref_flags
);
1571 bool is_rel
= (ref_flags
& Symbol::ABSOLUTE_REF
)
1572 && gsym
->can_use_relative_reloc(ref_flags
1573 & Symbol::FUNCTION_CALL
);
1574 return !has_dyn
|| is_rel
;
1577 // Perform a relocation.
1579 template<bool big_endian
>
1581 Target_arm
<big_endian
>::Relocate::relocate(
1582 const Relocate_info
<32, big_endian
>* relinfo
,
1584 Output_section
*output_section
,
1586 const elfcpp::Rel
<32, big_endian
>& rel
,
1587 unsigned int r_type
,
1588 const Sized_symbol
<32>* gsym
,
1589 const Symbol_value
<32>* psymval
,
1590 unsigned char* view
,
1591 elfcpp::Elf_types
<32>::Elf_Addr address
,
1592 section_size_type
/* view_size */ )
1594 typedef Arm_relocate_functions
<big_endian
> Arm_relocate_functions
;
1596 r_type
= get_real_reloc_type(r_type
);
1598 // If this the symbol may be a Thumb function, set thumb bit to 1.
1599 bool has_thumb_bit
= ((gsym
!= NULL
)
1600 && (gsym
->type() == elfcpp::STT_FUNC
1601 || gsym
->type() == elfcpp::STT_ARM_TFUNC
));
1603 // Pick the value to use for symbols defined in shared objects.
1604 Symbol_value
<32> symval
;
1606 && gsym
->use_plt_offset(reloc_is_non_pic(r_type
)))
1608 symval
.set_output_value(target
->plt_section()->address()
1609 + gsym
->plt_offset());
1614 const Sized_relobj
<32, big_endian
>* object
= relinfo
->object
;
1616 // Get the GOT offset if needed.
1617 // The GOT pointer points to the end of the GOT section.
1618 // We need to subtract the size of the GOT section to get
1619 // the actual offset to use in the relocation.
1620 bool have_got_offset
= false;
1621 unsigned int got_offset
= 0;
1624 case elfcpp::R_ARM_GOT_BREL
:
1627 gold_assert(gsym
->has_got_offset(GOT_TYPE_STANDARD
));
1628 got_offset
= (gsym
->got_offset(GOT_TYPE_STANDARD
)
1629 - target
->got_size());
1633 unsigned int r_sym
= elfcpp::elf_r_sym
<32>(rel
.get_r_info());
1634 gold_assert(object
->local_has_got_offset(r_sym
, GOT_TYPE_STANDARD
));
1635 got_offset
= (object
->local_got_offset(r_sym
, GOT_TYPE_STANDARD
)
1636 - target
->got_size());
1638 have_got_offset
= true;
1645 typename
Arm_relocate_functions::Status reloc_status
=
1646 Arm_relocate_functions::STATUS_OKAY
;
1649 case elfcpp::R_ARM_NONE
:
1652 case elfcpp::R_ARM_ABS8
:
1653 if (should_apply_static_reloc(gsym
, Symbol::ABSOLUTE_REF
, false,
1655 reloc_status
= Arm_relocate_functions::abs8(view
, object
, psymval
,
1659 case elfcpp::R_ARM_ABS32
:
1660 if (should_apply_static_reloc(gsym
, Symbol::ABSOLUTE_REF
, true,
1662 reloc_status
= Arm_relocate_functions::abs32(view
, object
, psymval
,
1666 case elfcpp::R_ARM_REL32
:
1667 reloc_status
= Arm_relocate_functions::rel32(view
, object
, psymval
,
1668 address
, has_thumb_bit
);
1671 case elfcpp::R_ARM_THM_CALL
:
1672 reloc_status
= Arm_relocate_functions::thm_call(view
, object
, psymval
,
1673 address
, has_thumb_bit
);
1676 case elfcpp::R_ARM_GOTOFF32
:
1678 elfcpp::Elf_types
<32>::Elf_Addr got_origin
;
1679 got_origin
= target
->got_plt_section()->address();
1680 reloc_status
= Arm_relocate_functions::rel32(view
, object
, psymval
,
1681 got_origin
, has_thumb_bit
);
1685 case elfcpp::R_ARM_BASE_PREL
:
1688 // Get the addressing origin of the output segment defining the
1689 // symbol gsym (AAELF 4.6.1.2 Relocation types)
1690 gold_assert(gsym
!= NULL
);
1691 if (gsym
->source() == Symbol::IN_OUTPUT_SEGMENT
)
1692 origin
= gsym
->output_segment()->vaddr();
1693 else if (gsym
->source () == Symbol::IN_OUTPUT_DATA
)
1694 origin
= gsym
->output_data()->address();
1697 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1698 _("cannot find origin of R_ARM_BASE_PREL"));
1701 reloc_status
= Arm_relocate_functions::base_prel(view
, origin
, address
);
1705 case elfcpp::R_ARM_GOT_BREL
:
1706 gold_assert(have_got_offset
);
1707 reloc_status
= Arm_relocate_functions::got_brel(view
, got_offset
);
1710 case elfcpp::R_ARM_PLT32
:
1711 gold_assert(gsym
== NULL
1712 || gsym
->has_plt_offset()
1713 || gsym
->final_value_is_known()
1714 || (gsym
->is_defined()
1715 && !gsym
->is_from_dynobj()
1716 && !gsym
->is_preemptible()));
1717 reloc_status
= Arm_relocate_functions::plt32(view
, object
, psymval
,
1718 address
, has_thumb_bit
);
1721 case elfcpp::R_ARM_CALL
:
1722 reloc_status
= Arm_relocate_functions::call(view
, object
, psymval
,
1723 address
, has_thumb_bit
);
1726 case elfcpp::R_ARM_JUMP24
:
1727 reloc_status
= Arm_relocate_functions::jump24(view
, object
, psymval
,
1728 address
, has_thumb_bit
);
1731 case elfcpp::R_ARM_PREL31
:
1732 reloc_status
= Arm_relocate_functions::prel31(view
, object
, psymval
,
1733 address
, has_thumb_bit
);
1736 case elfcpp::R_ARM_TARGET1
:
1737 // This should have been mapped to another type already.
1739 case elfcpp::R_ARM_COPY
:
1740 case elfcpp::R_ARM_GLOB_DAT
:
1741 case elfcpp::R_ARM_JUMP_SLOT
:
1742 case elfcpp::R_ARM_RELATIVE
:
1743 // These are relocations which should only be seen by the
1744 // dynamic linker, and should never be seen here.
1745 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1746 _("unexpected reloc %u in object file"),
1751 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1752 _("unsupported reloc %u"),
1757 // Report any errors.
1758 switch (reloc_status
)
1760 case Arm_relocate_functions::STATUS_OKAY
:
1762 case Arm_relocate_functions::STATUS_OVERFLOW
:
1763 gold_error_at_location(relinfo
, relnum
, rel
.get_r_offset(),
1764 _("relocation overflow in relocation %u"),
1767 case Arm_relocate_functions::STATUS_BAD_RELOC
:
1768 gold_error_at_location(
1772 _("unexpected opcode while processing relocation %u"),
1782 // Relocate section data.
1784 template<bool big_endian
>
1786 Target_arm
<big_endian
>::relocate_section(
1787 const Relocate_info
<32, big_endian
>* relinfo
,
1788 unsigned int sh_type
,
1789 const unsigned char* prelocs
,
1791 Output_section
* output_section
,
1792 bool needs_special_offset_handling
,
1793 unsigned char* view
,
1794 elfcpp::Elf_types
<32>::Elf_Addr address
,
1795 section_size_type view_size
)
1797 typedef typename Target_arm
<big_endian
>::Relocate Arm_relocate
;
1798 gold_assert(sh_type
== elfcpp::SHT_REL
);
1800 gold::relocate_section
<32, big_endian
, Target_arm
, elfcpp::SHT_REL
,
1807 needs_special_offset_handling
,
1813 // Return the size of a relocation while scanning during a relocatable
1816 template<bool big_endian
>
1818 Target_arm
<big_endian
>::Relocatable_size_for_reloc::get_size_for_reloc(
1819 unsigned int r_type
,
1822 r_type
= get_real_reloc_type(r_type
);
1825 case elfcpp::R_ARM_NONE
:
1828 case elfcpp::R_ARM_ABS8
:
1831 case elfcpp::R_ARM_ABS32
:
1832 case elfcpp::R_ARM_REL32
:
1833 case elfcpp::R_ARM_THM_CALL
:
1834 case elfcpp::R_ARM_GOTOFF32
:
1835 case elfcpp::R_ARM_BASE_PREL
:
1836 case elfcpp::R_ARM_GOT_BREL
:
1837 case elfcpp::R_ARM_PLT32
:
1838 case elfcpp::R_ARM_CALL
:
1839 case elfcpp::R_ARM_JUMP24
:
1840 case elfcpp::R_ARM_PREL31
:
1843 case elfcpp::R_ARM_TARGET1
:
1844 // This should have been mapped to another type already.
1846 case elfcpp::R_ARM_COPY
:
1847 case elfcpp::R_ARM_GLOB_DAT
:
1848 case elfcpp::R_ARM_JUMP_SLOT
:
1849 case elfcpp::R_ARM_RELATIVE
:
1850 // These are relocations which should only be seen by the
1851 // dynamic linker, and should never be seen here.
1852 gold_error(_("%s: unexpected reloc %u in object file"),
1853 object
->name().c_str(), r_type
);
1857 object
->error(_("unsupported reloc %u in object file"), r_type
);
1862 // Scan the relocs during a relocatable link.
1864 template<bool big_endian
>
1866 Target_arm
<big_endian
>::scan_relocatable_relocs(
1867 const General_options
& options
,
1868 Symbol_table
* symtab
,
1870 Sized_relobj
<32, big_endian
>* object
,
1871 unsigned int data_shndx
,
1872 unsigned int sh_type
,
1873 const unsigned char* prelocs
,
1875 Output_section
* output_section
,
1876 bool needs_special_offset_handling
,
1877 size_t local_symbol_count
,
1878 const unsigned char* plocal_symbols
,
1879 Relocatable_relocs
* rr
)
1881 gold_assert(sh_type
== elfcpp::SHT_REL
);
1883 typedef gold::Default_scan_relocatable_relocs
<elfcpp::SHT_REL
,
1884 Relocatable_size_for_reloc
> Scan_relocatable_relocs
;
1886 gold::scan_relocatable_relocs
<32, big_endian
, elfcpp::SHT_REL
,
1887 Scan_relocatable_relocs
>(
1896 needs_special_offset_handling
,
1902 // Relocate a section during a relocatable link.
1904 template<bool big_endian
>
1906 Target_arm
<big_endian
>::relocate_for_relocatable(
1907 const Relocate_info
<32, big_endian
>* relinfo
,
1908 unsigned int sh_type
,
1909 const unsigned char* prelocs
,
1911 Output_section
* output_section
,
1912 off_t offset_in_output_section
,
1913 const Relocatable_relocs
* rr
,
1914 unsigned char* view
,
1915 elfcpp::Elf_types
<32>::Elf_Addr view_address
,
1916 section_size_type view_size
,
1917 unsigned char* reloc_view
,
1918 section_size_type reloc_view_size
)
1920 gold_assert(sh_type
== elfcpp::SHT_REL
);
1922 gold::relocate_for_relocatable
<32, big_endian
, elfcpp::SHT_REL
>(
1927 offset_in_output_section
,
1936 // Return the value to use for a dynamic symbol which requires special
1937 // treatment. This is how we support equality comparisons of function
1938 // pointers across shared library boundaries, as described in the
1939 // processor specific ABI supplement.
1941 template<bool big_endian
>
1943 Target_arm
<big_endian
>::do_dynsym_value(const Symbol
* gsym
) const
1945 gold_assert(gsym
->is_from_dynobj() && gsym
->has_plt_offset());
1946 return this->plt_section()->address() + gsym
->plt_offset();
1949 // Map platform-specific relocs to real relocs
1951 template<bool big_endian
>
1953 Target_arm
<big_endian
>::get_real_reloc_type (unsigned int r_type
)
1957 case elfcpp::R_ARM_TARGET1
:
1958 // This is either R_ARM_ABS32 or R_ARM_REL32;
1959 return elfcpp::R_ARM_ABS32
;
1961 case elfcpp::R_ARM_TARGET2
:
1962 // This can be any reloc type but ususally is R_ARM_GOT_PREL
1963 return elfcpp::R_ARM_GOT_PREL
;
1970 // The selector for arm object files.
1972 template<bool big_endian
>
1973 class Target_selector_arm
: public Target_selector
1976 Target_selector_arm()
1977 : Target_selector(elfcpp::EM_ARM
, 32, big_endian
,
1978 (big_endian
? "elf32-bigarm" : "elf32-littlearm"))
1982 do_instantiate_target()
1983 { return new Target_arm
<big_endian
>(); }
1986 Target_selector_arm
<false> target_selector_arm
;
1987 Target_selector_arm
<true> target_selector_armbe
;
1989 } // End anonymous namespace.