| // arm.cc -- arm target support for gold. |
| |
| // Copyright 2009 Free Software Foundation, Inc. |
| // Written by Doug Kwan <dougkwan@google.com> based on the i386 code |
| // by Ian Lance Taylor <iant@google.com>. |
| |
| // This file is part of gold. |
| |
| // This program is free software; you can redistribute it and/or modify |
| // it under the terms of the GNU General Public License as published by |
| // the Free Software Foundation; either version 3 of the License, or |
| // (at your option) any later version. |
| |
| // This program is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License |
| // along with this program; if not, write to the Free Software |
| // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| // MA 02110-1301, USA. |
| |
| #include "gold.h" |
| |
| #include <cstring> |
| #include <limits> |
| #include <cstdio> |
| #include <string> |
| |
| #include "elfcpp.h" |
| #include "parameters.h" |
| #include "reloc.h" |
| #include "arm.h" |
| #include "object.h" |
| #include "symtab.h" |
| #include "layout.h" |
| #include "output.h" |
| #include "copy-relocs.h" |
| #include "target.h" |
| #include "target-reloc.h" |
| #include "target-select.h" |
| #include "tls.h" |
| #include "defstd.h" |
| |
| namespace |
| { |
| |
| using namespace gold; |
| |
| template<bool big_endian> |
| class Output_data_plt_arm; |
| |
| // The arm target class. |
| // |
| // This is a very simple port of gold for ARM-EABI. It is intended for |
| // supporting Android only for the time being. Only these relocation types |
| // are supported. |
| // |
| // R_ARM_NONE |
| // R_ARM_ABS32 |
| // R_ARM_REL32 |
| // R_ARM_THM_CALL |
| // R_ARM_COPY |
| // R_ARM_GLOB_DAT |
| // R_ARM_BASE_PREL |
| // R_ARM_JUMP_SLOT |
| // R_ARM_RELATIVE |
| // R_ARM_GOTOFF32 |
| // R_ARM_GOT_BREL |
| // R_ARM_PLT32 |
| // R_ARM_CALL |
| // R_ARM_JUMP24 |
| // R_ARM_TARGET1 |
| // R_ARM_PREL31 |
| // |
| // TODOs: |
| // - Generate various branch stubs. |
| // - Support interworking. |
| // - Define section symbols __exidx_start and __exidx_stop. |
| // - Support more relocation types as needed. |
| // - Make PLTs more flexible for different architecture features like |
| // Thumb-2 and BE8. |
| // There are probably a lot more. |
| |
| // Utilities for manipulating integers of up to 32-bits |
| |
| namespace utils |
| { |
| // Sign extend an n-bit unsigned integer stored in an uint32_t into |
| // an int32_t. NO_BITS must be between 1 to 32. |
| template<int no_bits> |
| static inline int32_t |
| sign_extend(uint32_t bits) |
| { |
| gold_assert(no_bits >= 0 && no_bits <= 32); |
| if (no_bits == 32) |
| return static_cast<int32_t>(bits); |
| uint32_t mask = (~((uint32_t) 0)) >> (32 - no_bits); |
| bits &= mask; |
| uint32_t top_bit = 1U << (no_bits - 1); |
| int32_t as_signed = static_cast<int32_t>(bits); |
| return (bits & top_bit) ? as_signed + (-top_bit * 2) : as_signed; |
| } |
| |
| // Detects overflow of an NO_BITS integer stored in a uint32_t. |
| template<int no_bits> |
| static inline bool |
| has_overflow(uint32_t bits) |
| { |
| gold_assert(no_bits >= 0 && no_bits <= 32); |
| if (no_bits == 32) |
| return false; |
| int32_t max = (1 << (no_bits - 1)) - 1; |
| int32_t min = -(1 << (no_bits - 1)); |
| int32_t as_signed = static_cast<int32_t>(bits); |
| return as_signed > max || as_signed < min; |
| } |
| |
| // Select bits from A and B using bits in MASK. For each n in [0..31], |
| // the n-th bit in the result is chosen from the n-th bits of A and B. |
| // A zero selects A and a one selects B. |
| static inline uint32_t |
| bit_select(uint32_t a, uint32_t b, uint32_t mask) |
| { return (a & ~mask) | (b & mask); } |
| }; |
| |
| template<bool big_endian> |
| class Target_arm : public Sized_target<32, big_endian> |
| { |
| public: |
| typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, big_endian> |
| Reloc_section; |
| |
| Target_arm() |
| : Sized_target<32, big_endian>(&arm_info), |
| got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL), |
| copy_relocs_(elfcpp::R_ARM_COPY), dynbss_(NULL) |
| { } |
| |
| // Process the relocations to determine unreferenced sections for |
| // garbage collection. |
| void |
| gc_process_relocs(const General_options& options, |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<32, big_endian>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols); |
| |
| // Scan the relocations to look for symbol adjustments. |
| void |
| scan_relocs(const General_options& options, |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<32, big_endian>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols); |
| |
| // Finalize the sections. |
| void |
| do_finalize_sections(Layout*); |
| |
| // Return the value to use for a dynamic symbol which requires special |
| // treatment. |
| uint64_t |
| do_dynsym_value(const Symbol*) const; |
| |
| // Relocate a section. |
| void |
| relocate_section(const Relocate_info<32, big_endian>*, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr view_address, |
| section_size_type view_size); |
| |
| // Scan the relocs during a relocatable link. |
| void |
| scan_relocatable_relocs(const General_options& options, |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<32, big_endian>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols, |
| Relocatable_relocs*); |
| |
| // Relocate a section during a relocatable link. |
| void |
| relocate_for_relocatable(const Relocate_info<32, big_endian>*, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| off_t offset_in_output_section, |
| const Relocatable_relocs*, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr view_address, |
| section_size_type view_size, |
| unsigned char* reloc_view, |
| section_size_type reloc_view_size); |
| |
| // Return whether SYM is defined by the ABI. |
| bool |
| do_is_defined_by_abi(Symbol* sym) const |
| { return strcmp(sym->name(), "__tls_get_addr") == 0; } |
| |
| // Return the size of the GOT section. |
| section_size_type |
| got_size() |
| { |
| gold_assert(this->got_ != NULL); |
| return this->got_->data_size(); |
| } |
| |
| // Map platform-specific reloc types |
| static unsigned int |
| get_real_reloc_type (unsigned int r_type); |
| |
| private: |
| // The class which scans relocations. |
| class Scan |
| { |
| public: |
| Scan() |
| : issued_non_pic_error_(false) |
| { } |
| |
| inline void |
| local(const General_options& options, Symbol_table* symtab, |
| Layout* layout, Target_arm* target, |
| Sized_relobj<32, big_endian>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, big_endian>& reloc, unsigned int r_type, |
| const elfcpp::Sym<32, big_endian>& lsym); |
| |
| inline void |
| global(const General_options& options, Symbol_table* symtab, |
| Layout* layout, Target_arm* target, |
| Sized_relobj<32, big_endian>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, big_endian>& reloc, unsigned int r_type, |
| Symbol* gsym); |
| |
| private: |
| static void |
| unsupported_reloc_local(Sized_relobj<32, big_endian>*, |
| unsigned int r_type); |
| |
| static void |
| unsupported_reloc_global(Sized_relobj<32, big_endian>*, |
| unsigned int r_type, Symbol*); |
| |
| void |
| check_non_pic(Relobj*, unsigned int r_type); |
| |
| // Almost identical to Symbol::needs_plt_entry except that it also |
| // handles STT_ARM_TFUNC. |
| static bool |
| symbol_needs_plt_entry(const Symbol* sym) |
| { |
| // An undefined symbol from an executable does not need a PLT entry. |
| if (sym->is_undefined() && !parameters->options().shared()) |
| return false; |
| |
| return (!parameters->doing_static_link() |
| && (sym->type() == elfcpp::STT_FUNC |
| || sym->type() == elfcpp::STT_ARM_TFUNC) |
| && (sym->is_from_dynobj() |
| || sym->is_undefined() |
| || sym->is_preemptible())); |
| } |
| |
| // Whether we have issued an error about a non-PIC compilation. |
| bool issued_non_pic_error_; |
| }; |
| |
| // The class which implements relocation. |
| class Relocate |
| { |
| public: |
| Relocate() |
| { } |
| |
| ~Relocate() |
| { } |
| |
| // Return whether the static relocation needs to be applied. |
| inline bool |
| should_apply_static_reloc(const Sized_symbol<32>* gsym, |
| int ref_flags, |
| bool is_32bit, |
| Output_section* output_section); |
| |
| // Do a relocation. Return false if the caller should not issue |
| // any warnings about this relocation. |
| inline bool |
| relocate(const Relocate_info<32, big_endian>*, Target_arm*, |
| Output_section*, size_t relnum, |
| const elfcpp::Rel<32, big_endian>&, |
| unsigned int r_type, const Sized_symbol<32>*, |
| const Symbol_value<32>*, |
| unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, |
| section_size_type); |
| |
| // Return whether we want to pass flag NON_PIC_REF for this |
| // reloc. |
| static inline bool |
| reloc_is_non_pic (unsigned int r_type) |
| { |
| switch (r_type) |
| { |
| case elfcpp::R_ARM_REL32: |
| case elfcpp::R_ARM_THM_CALL: |
| case elfcpp::R_ARM_CALL: |
| case elfcpp::R_ARM_JUMP24: |
| case elfcpp::R_ARM_PREL31: |
| return true; |
| default: |
| return false; |
| } |
| } |
| }; |
| |
| // A class which returns the size required for a relocation type, |
| // used while scanning relocs during a relocatable link. |
| class Relocatable_size_for_reloc |
| { |
| public: |
| unsigned int |
| get_size_for_reloc(unsigned int, Relobj*); |
| }; |
| |
| // Get the GOT section, creating it if necessary. |
| Output_data_got<32, big_endian>* |
| got_section(Symbol_table*, Layout*); |
| |
| // Get the GOT PLT section. |
| Output_data_space* |
| got_plt_section() const |
| { |
| gold_assert(this->got_plt_ != NULL); |
| return this->got_plt_; |
| } |
| |
| // Create a PLT entry for a global symbol. |
| void |
| make_plt_entry(Symbol_table*, Layout*, Symbol*); |
| |
| // Get the PLT section. |
| const Output_data_plt_arm<big_endian>* |
| plt_section() const |
| { |
| gold_assert(this->plt_ != NULL); |
| return this->plt_; |
| } |
| |
| // Get the dynamic reloc section, creating it if necessary. |
| Reloc_section* |
| rel_dyn_section(Layout*); |
| |
| // Return true if the symbol may need a COPY relocation. |
| // References from an executable object to non-function symbols |
| // defined in a dynamic object may need a COPY relocation. |
| bool |
| may_need_copy_reloc(Symbol* gsym) |
| { |
| return (!parameters->options().shared() |
| && gsym->is_from_dynobj() |
| && gsym->type() != elfcpp::STT_FUNC |
| && gsym->type() != elfcpp::STT_ARM_TFUNC); |
| } |
| |
| // Add a potential copy relocation. |
| void |
| copy_reloc(Symbol_table* symtab, Layout* layout, |
| Sized_relobj<32, big_endian>* object, |
| unsigned int shndx, Output_section* output_section, |
| Symbol* sym, const elfcpp::Rel<32, big_endian>& reloc) |
| { |
| this->copy_relocs_.copy_reloc(symtab, layout, |
| symtab->get_sized_symbol<32>(sym), |
| object, shndx, output_section, reloc, |
| this->rel_dyn_section(layout)); |
| } |
| |
| // Information about this specific target which we pass to the |
| // general Target structure. |
| static const Target::Target_info arm_info; |
| |
| // The types of GOT entries needed for this platform. |
| enum Got_type |
| { |
| GOT_TYPE_STANDARD = 0 // GOT entry for a regular symbol |
| }; |
| |
| // The GOT section. |
| Output_data_got<32, big_endian>* got_; |
| // The PLT section. |
| Output_data_plt_arm<big_endian>* plt_; |
| // The GOT PLT section. |
| Output_data_space* got_plt_; |
| // The dynamic reloc section. |
| Reloc_section* rel_dyn_; |
| // Relocs saved to avoid a COPY reloc. |
| Copy_relocs<elfcpp::SHT_REL, 32, big_endian> copy_relocs_; |
| // Space for variables copied with a COPY reloc. |
| Output_data_space* dynbss_; |
| }; |
| |
| template<bool big_endian> |
| const Target::Target_info Target_arm<big_endian>::arm_info = |
| { |
| 32, // size |
| big_endian, // is_big_endian |
| elfcpp::EM_ARM, // machine_code |
| false, // has_make_symbol |
| false, // has_resolve |
| false, // has_code_fill |
| true, // is_default_stack_executable |
| '\0', // wrap_char |
| "/usr/lib/libc.so.1", // dynamic_linker |
| 0x8000, // default_text_segment_address |
| 0x1000, // abi_pagesize (overridable by -z max-page-size) |
| 0x1000, // common_pagesize (overridable by -z common-page-size) |
| elfcpp::SHN_UNDEF, // small_common_shndx |
| elfcpp::SHN_UNDEF, // large_common_shndx |
| 0, // small_common_section_flags |
| 0 // large_common_section_flags |
| }; |
| |
| // Arm relocate functions class |
| // |
| |
| template<bool big_endian> |
| class Arm_relocate_functions : public Relocate_functions<32, big_endian> |
| { |
| public: |
| typedef enum |
| { |
| STATUS_OKAY, // No error during relocation. |
| STATUS_OVERFLOW, // Relocation oveflow. |
| STATUS_BAD_RELOC // Relocation cannot be applied. |
| } Status; |
| |
| private: |
| typedef Relocate_functions<32, big_endian> Base; |
| typedef Arm_relocate_functions<big_endian> This; |
| |
| // Get an symbol value of *PSYMVAL with an ADDEND. This is a wrapper |
| // to Symbol_value::value(). If HAS_THUMB_BIT is true, that LSB is used |
| // to distinguish ARM and THUMB functions and it is treated specially. |
| static inline Symbol_value<32>::Value |
| arm_symbol_value (const Sized_relobj<32, big_endian> *object, |
| const Symbol_value<32>* psymval, |
| Symbol_value<32>::Value addend, |
| bool has_thumb_bit) |
| { |
| typedef Symbol_value<32>::Value Valtype; |
| |
| if (has_thumb_bit) |
| { |
| Valtype raw = psymval->value(object, 0); |
| Valtype thumb_bit = raw & 1; |
| return ((raw & ~((Valtype) 1)) + addend) | thumb_bit; |
| } |
| else |
| return psymval->value(object, addend); |
| } |
| |
| // FIXME: This probably only works for Android on ARM v5te. We should |
| // following GNU ld for the general case. |
| template<unsigned r_type> |
| static inline typename This::Status |
| arm_branch_common(unsigned char *view, |
| const Sized_relobj<32, big_endian>* object, |
| const Symbol_value<32>* psymval, |
| elfcpp::Elf_types<32>::Elf_Addr address, |
| bool has_thumb_bit) |
| { |
| typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; |
| Valtype* wv = reinterpret_cast<Valtype*>(view); |
| Valtype val = elfcpp::Swap<32, big_endian>::readval(wv); |
| |
| bool insn_is_b = (((val >> 28) & 0xf) <= 0xe) |
| && ((val & 0x0f000000UL) == 0x0a000000UL); |
| bool insn_is_uncond_bl = (val & 0xff000000UL) == 0xeb000000UL; |
| bool insn_is_cond_bl = (((val >> 28) & 0xf) < 0xe) |
| && ((val & 0x0f000000UL) == 0x0b000000UL); |
| bool insn_is_blx = (val & 0xfe000000UL) == 0xfa000000UL; |
| bool insn_is_any_branch = (val & 0x0e000000UL) == 0x0a000000UL; |
| |
| if (r_type == elfcpp::R_ARM_CALL) |
| { |
| if (!insn_is_uncond_bl && !insn_is_blx) |
| return This::STATUS_BAD_RELOC; |
| } |
| else if (r_type == elfcpp::R_ARM_JUMP24) |
| { |
| if (!insn_is_b && !insn_is_cond_bl) |
| return This::STATUS_BAD_RELOC; |
| } |
| else if (r_type == elfcpp::R_ARM_PLT32) |
| { |
| if (!insn_is_any_branch) |
| return This::STATUS_BAD_RELOC; |
| } |
| else |
| gold_unreachable(); |
| |
| Valtype addend = utils::sign_extend<26>(val << 2); |
| Valtype x = (This::arm_symbol_value(object, psymval, addend, has_thumb_bit) |
| - address); |
| |
| // If target has thumb bit set, we need to either turn the BL |
| // into a BLX (for ARMv5 or above) or generate a stub. |
| if (x & 1) |
| { |
| // Turn BL to BLX. |
| if (insn_is_uncond_bl) |
| val = (val & 0xffffff) | 0xfa000000 | ((x & 2) << 23); |
| else |
| return This::STATUS_BAD_RELOC; |
| } |
| else |
| gold_assert(!insn_is_blx); |
| |
| val = utils::bit_select(val, (x >> 2), 0xffffffUL); |
| elfcpp::Swap<32, big_endian>::writeval(wv, val); |
| return (utils::has_overflow<26>(x) |
| ? This::STATUS_OVERFLOW : This::STATUS_OKAY); |
| } |
| |
| public: |
| // R_ARM_ABS32: (S + A) | T |
| static inline typename This::Status |
| abs32(unsigned char *view, |
| const Sized_relobj<32, big_endian>* object, |
| const Symbol_value<32>* psymval, |
| bool has_thumb_bit) |
| { |
| typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; |
| Valtype* wv = reinterpret_cast<Valtype*>(view); |
| Valtype addend = elfcpp::Swap<32, big_endian>::readval(wv); |
| Valtype x = This::arm_symbol_value(object, psymval, addend, has_thumb_bit); |
| elfcpp::Swap<32, big_endian>::writeval(wv, x); |
| return This::STATUS_OKAY; |
| } |
| |
| // R_ARM_REL32: (S + A) | T - P |
| static inline typename This::Status |
| rel32(unsigned char *view, |
| const Sized_relobj<32, big_endian>* object, |
| const Symbol_value<32>* psymval, |
| elfcpp::Elf_types<32>::Elf_Addr address, |
| bool has_thumb_bit) |
| { |
| typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; |
| Valtype* wv = reinterpret_cast<Valtype*>(view); |
| Valtype addend = elfcpp::Swap<32, big_endian>::readval(wv); |
| Valtype x = (This::arm_symbol_value(object, psymval, addend, has_thumb_bit) |
| - address); |
| elfcpp::Swap<32, big_endian>::writeval(wv, x); |
| return This::STATUS_OKAY; |
| } |
| |
| // R_ARM_THM_CALL: (S + A) | T - P |
| static inline typename This::Status |
| thm_call(unsigned char *view, |
| const Sized_relobj<32, big_endian>* object, |
| const Symbol_value<32>* psymval, |
| elfcpp::Elf_types<32>::Elf_Addr address, |
| bool has_thumb_bit) |
| { |
| // A thumb call consists of two instructions. |
| typedef typename elfcpp::Swap<16, big_endian>::Valtype Valtype; |
| typedef typename elfcpp::Swap<32, big_endian>::Valtype Reltype; |
| Valtype* wv = reinterpret_cast<Valtype*>(view); |
| Valtype hi = elfcpp::Swap<16, big_endian>::readval(wv); |
| Valtype lo = elfcpp::Swap<16, big_endian>::readval(wv + 1); |
| // Must be a BL instruction. lo == 11111xxxxxxxxxxx. |
| gold_assert((lo & 0xf800) == 0xf800); |
| Reltype addend = utils::sign_extend<23>(((hi & 0x7ff) << 12) |
| | ((lo & 0x7ff) << 1)); |
| Reltype x = (This::arm_symbol_value(object, psymval, addend, has_thumb_bit) |
| - address); |
| |
| // If target has no thumb bit set, we need to either turn the BL |
| // into a BLX (for ARMv5 or above) or generate a stub. |
| if ((x & 1) == 0) |
| { |
| // This only works for ARMv5 and above with interworking enabled. |
| lo &= 0xefff; |
| } |
| hi = utils::bit_select(hi, (x >> 12), 0x7ffU); |
| lo = utils::bit_select(lo, (x >> 1), 0x7ffU); |
| elfcpp::Swap<16, big_endian>::writeval(wv, hi); |
| elfcpp::Swap<16, big_endian>::writeval(wv + 1, lo); |
| return (utils::has_overflow<23>(x) |
| ? This::STATUS_OVERFLOW |
| : This::STATUS_OKAY); |
| } |
| |
| // R_ARM_BASE_PREL: B(S) + A - P |
| static inline typename This::Status |
| base_prel(unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr origin, |
| elfcpp::Elf_types<32>::Elf_Addr address) |
| { |
| Base::rel32(view, origin - address); |
| return STATUS_OKAY; |
| } |
| |
| // R_ARM_GOT_BREL: GOT(S) + A - GOT_ORG |
| static inline typename This::Status |
| got_brel(unsigned char* view, |
| typename elfcpp::Swap<32, big_endian>::Valtype got_offset) |
| { |
| Base::rel32(view, got_offset); |
| return This::STATUS_OKAY; |
| } |
| |
| // R_ARM_PLT32: (S + A) | T - P |
| static inline typename This::Status |
| plt32(unsigned char *view, |
| const Sized_relobj<32, big_endian>* object, |
| const Symbol_value<32>* psymval, |
| elfcpp::Elf_types<32>::Elf_Addr address, |
| bool has_thumb_bit) |
| { |
| return arm_branch_common<elfcpp::R_ARM_PLT32>(view, object, psymval, |
| address, has_thumb_bit); |
| } |
| |
| // R_ARM_CALL: (S + A) | T - P |
| static inline typename This::Status |
| call(unsigned char *view, |
| const Sized_relobj<32, big_endian>* object, |
| const Symbol_value<32>* psymval, |
| elfcpp::Elf_types<32>::Elf_Addr address, |
| bool has_thumb_bit) |
| { |
| return arm_branch_common<elfcpp::R_ARM_CALL>(view, object, psymval, |
| address, has_thumb_bit); |
| } |
| |
| // R_ARM_JUMP24: (S + A) | T - P |
| static inline typename This::Status |
| jump24(unsigned char *view, |
| const Sized_relobj<32, big_endian>* object, |
| const Symbol_value<32>* psymval, |
| elfcpp::Elf_types<32>::Elf_Addr address, |
| bool has_thumb_bit) |
| { |
| return arm_branch_common<elfcpp::R_ARM_JUMP24>(view, object, psymval, |
| address, has_thumb_bit); |
| } |
| |
| // R_ARM_PREL: (S + A) | T - P |
| static inline typename This::Status |
| prel31(unsigned char *view, |
| const Sized_relobj<32, big_endian>* object, |
| const Symbol_value<32>* psymval, |
| elfcpp::Elf_types<32>::Elf_Addr address, |
| bool has_thumb_bit) |
| { |
| typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; |
| Valtype* wv = reinterpret_cast<Valtype*>(view); |
| Valtype val = elfcpp::Swap<32, big_endian>::readval(wv); |
| Valtype addend = utils::sign_extend<31>(val); |
| Valtype x = (This::arm_symbol_value(object, psymval, addend, has_thumb_bit) |
| - address); |
| val = utils::bit_select(val, x, 0x7fffffffU); |
| elfcpp::Swap<32, big_endian>::writeval(wv, val); |
| return (utils::has_overflow<31>(x) ? |
| This::STATUS_OVERFLOW : This::STATUS_OKAY); |
| } |
| }; |
| |
| // Get the GOT section, creating it if necessary. |
| |
| template<bool big_endian> |
| Output_data_got<32, big_endian>* |
| Target_arm<big_endian>::got_section(Symbol_table* symtab, Layout* layout) |
| { |
| if (this->got_ == NULL) |
| { |
| gold_assert(symtab != NULL && layout != NULL); |
| |
| this->got_ = new Output_data_got<32, big_endian>(); |
| |
| Output_section* os; |
| os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->got_); |
| os->set_is_relro(); |
| |
| // The old GNU linker creates a .got.plt section. We just |
| // create another set of data in the .got section. Note that we |
| // always create a PLT if we create a GOT, although the PLT |
| // might be empty. |
| this->got_plt_ = new Output_data_space(4, "** GOT PLT"); |
| os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->got_plt_); |
| os->set_is_relro(); |
| |
| // The first three entries are reserved. |
| this->got_plt_->set_current_data_size(3 * 4); |
| |
| // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. |
| symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, |
| this->got_plt_, |
| 0, 0, elfcpp::STT_OBJECT, |
| elfcpp::STB_LOCAL, |
| elfcpp::STV_HIDDEN, 0, |
| false, false); |
| } |
| return this->got_; |
| } |
| |
| // Get the dynamic reloc section, creating it if necessary. |
| |
| template<bool big_endian> |
| typename Target_arm<big_endian>::Reloc_section* |
| Target_arm<big_endian>::rel_dyn_section(Layout* layout) |
| { |
| if (this->rel_dyn_ == NULL) |
| { |
| gold_assert(layout != NULL); |
| this->rel_dyn_ = new Reloc_section(parameters->options().combreloc()); |
| layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL, |
| elfcpp::SHF_ALLOC, this->rel_dyn_); |
| } |
| return this->rel_dyn_; |
| } |
| |
| // A class to handle the PLT data. |
| |
| template<bool big_endian> |
| class Output_data_plt_arm : public Output_section_data |
| { |
| public: |
| typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, big_endian> |
| Reloc_section; |
| |
| Output_data_plt_arm(Layout*, Output_data_space*); |
| |
| // Add an entry to the PLT. |
| void |
| add_entry(Symbol* gsym); |
| |
| // Return the .rel.plt section data. |
| const Reloc_section* |
| rel_plt() const |
| { return this->rel_; } |
| |
| protected: |
| void |
| do_adjust_output_section(Output_section* os); |
| |
| // Write to a map file. |
| void |
| do_print_to_mapfile(Mapfile* mapfile) const |
| { mapfile->print_output_data(this, _("** PLT")); } |
| |
| private: |
| // Template for the first PLT entry. |
| static const uint32_t first_plt_entry[5]; |
| |
| // Template for subsequent PLT entries. |
| static const uint32_t plt_entry[3]; |
| |
| // Set the final size. |
| void |
| set_final_data_size() |
| { |
| this->set_data_size(sizeof(first_plt_entry) |
| + this->count_ * sizeof(plt_entry)); |
| } |
| |
| // Write out the PLT data. |
| void |
| do_write(Output_file*); |
| |
| // The reloc section. |
| Reloc_section* rel_; |
| // The .got.plt section. |
| Output_data_space* got_plt_; |
| // The number of PLT entries. |
| unsigned int count_; |
| }; |
| |
| // Create the PLT section. The ordinary .got section is an argument, |
| // since we need to refer to the start. We also create our own .got |
| // section just for PLT entries. |
| |
| template<bool big_endian> |
| Output_data_plt_arm<big_endian>::Output_data_plt_arm(Layout* layout, |
| Output_data_space* got_plt) |
| : Output_section_data(4), got_plt_(got_plt), count_(0) |
| { |
| this->rel_ = new Reloc_section(false); |
| layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, |
| elfcpp::SHF_ALLOC, this->rel_); |
| } |
| |
| template<bool big_endian> |
| void |
| Output_data_plt_arm<big_endian>::do_adjust_output_section(Output_section* os) |
| { |
| os->set_entsize(0); |
| } |
| |
| // Add an entry to the PLT. |
| |
| template<bool big_endian> |
| void |
| Output_data_plt_arm<big_endian>::add_entry(Symbol* gsym) |
| { |
| gold_assert(!gsym->has_plt_offset()); |
| |
| // Note that when setting the PLT offset we skip the initial |
| // reserved PLT entry. |
| gsym->set_plt_offset((this->count_) * sizeof(plt_entry) |
| + sizeof(first_plt_entry)); |
| |
| ++this->count_; |
| |
| section_offset_type got_offset = this->got_plt_->current_data_size(); |
| |
| // Every PLT entry needs a GOT entry which points back to the PLT |
| // entry (this will be changed by the dynamic linker, normally |
| // lazily when the function is called). |
| this->got_plt_->set_current_data_size(got_offset + 4); |
| |
| // Every PLT entry needs a reloc. |
| gsym->set_needs_dynsym_entry(); |
| this->rel_->add_global(gsym, elfcpp::R_ARM_JUMP_SLOT, this->got_plt_, |
| got_offset); |
| |
| // Note that we don't need to save the symbol. The contents of the |
| // PLT are independent of which symbols are used. The symbols only |
| // appear in the relocations. |
| } |
| |
| // ARM PLTs. |
| // FIXME: This is not very flexible. Right now this has only been tested |
| // on armv5te. If we are to support additional architecture features like |
| // Thumb-2 or BE8, we need to make this more flexible like GNU ld. |
| |
| // The first entry in the PLT. |
| template<bool big_endian> |
| const uint32_t Output_data_plt_arm<big_endian>::first_plt_entry[5] = |
| { |
| 0xe52de004, // str lr, [sp, #-4]! |
| 0xe59fe004, // ldr lr, [pc, #4] |
| 0xe08fe00e, // add lr, pc, lr |
| 0xe5bef008, // ldr pc, [lr, #8]! |
| 0x00000000, // &GOT[0] - . |
| }; |
| |
| // Subsequent entries in the PLT. |
| |
| template<bool big_endian> |
| const uint32_t Output_data_plt_arm<big_endian>::plt_entry[3] = |
| { |
| 0xe28fc600, // add ip, pc, #0xNN00000 |
| 0xe28cca00, // add ip, ip, #0xNN000 |
| 0xe5bcf000, // ldr pc, [ip, #0xNNN]! |
| }; |
| |
| // Write out the PLT. This uses the hand-coded instructions above, |
| // and adjusts them as needed. This is all specified by the arm ELF |
| // Processor Supplement. |
| |
| template<bool big_endian> |
| void |
| Output_data_plt_arm<big_endian>::do_write(Output_file* of) |
| { |
| const off_t offset = this->offset(); |
| const section_size_type oview_size = |
| convert_to_section_size_type(this->data_size()); |
| unsigned char* const oview = of->get_output_view(offset, oview_size); |
| |
| const off_t got_file_offset = this->got_plt_->offset(); |
| const section_size_type got_size = |
| convert_to_section_size_type(this->got_plt_->data_size()); |
| unsigned char* const got_view = of->get_output_view(got_file_offset, |
| got_size); |
| unsigned char* pov = oview; |
| |
| elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address(); |
| elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address(); |
| |
| // Write first PLT entry. All but the last word are constants. |
| const size_t num_first_plt_words = (sizeof(first_plt_entry) |
| / sizeof(plt_entry[0])); |
| for (size_t i = 0; i < num_first_plt_words - 1; i++) |
| elfcpp::Swap<32, big_endian>::writeval(pov + i * 4, first_plt_entry[i]); |
| // Last word in first PLT entry is &GOT[0] - . |
| elfcpp::Swap<32, big_endian>::writeval(pov + 16, |
| got_address - (plt_address + 16)); |
| pov += sizeof(first_plt_entry); |
| |
| unsigned char* got_pov = got_view; |
| |
| memset(got_pov, 0, 12); |
| got_pov += 12; |
| |
| const int rel_size = elfcpp::Elf_sizes<32>::rel_size; |
| unsigned int plt_offset = sizeof(first_plt_entry); |
| unsigned int plt_rel_offset = 0; |
| unsigned int got_offset = 12; |
| const unsigned int count = this->count_; |
| for (unsigned int i = 0; |
| i < count; |
| ++i, |
| pov += sizeof(plt_entry), |
| got_pov += 4, |
| plt_offset += sizeof(plt_entry), |
| plt_rel_offset += rel_size, |
| got_offset += 4) |
| { |
| // Set and adjust the PLT entry itself. |
| int32_t offset = ((got_address + got_offset) |
| - (plt_address + plt_offset + 8)); |
| |
| gold_assert(offset >= 0 && offset < 0x0fffffff); |
| uint32_t plt_insn0 = plt_entry[0] | ((offset >> 20) & 0xff); |
| elfcpp::Swap<32, big_endian>::writeval(pov, plt_insn0); |
| uint32_t plt_insn1 = plt_entry[1] | ((offset >> 12) & 0xff); |
| elfcpp::Swap<32, big_endian>::writeval(pov + 4, plt_insn1); |
| uint32_t plt_insn2 = plt_entry[2] | (offset & 0xfff); |
| elfcpp::Swap<32, big_endian>::writeval(pov + 8, plt_insn2); |
| |
| // Set the entry in the GOT. |
| elfcpp::Swap<32, big_endian>::writeval(got_pov, plt_address); |
| } |
| |
| gold_assert(static_cast<section_size_type>(pov - oview) == oview_size); |
| gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size); |
| |
| of->write_output_view(offset, oview_size, oview); |
| of->write_output_view(got_file_offset, got_size, got_view); |
| } |
| |
| // Create a PLT entry for a global symbol. |
| |
| template<bool big_endian> |
| void |
| Target_arm<big_endian>::make_plt_entry(Symbol_table* symtab, Layout* layout, |
| Symbol* gsym) |
| { |
| if (gsym->has_plt_offset()) |
| return; |
| |
| if (this->plt_ == NULL) |
| { |
| // Create the GOT sections first. |
| this->got_section(symtab, layout); |
| |
| this->plt_ = new Output_data_plt_arm<big_endian>(layout, this->got_plt_); |
| layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_EXECINSTR), |
| this->plt_); |
| } |
| this->plt_->add_entry(gsym); |
| } |
| |
| // Report an unsupported relocation against a local symbol. |
| |
| template<bool big_endian> |
| void |
| Target_arm<big_endian>::Scan::unsupported_reloc_local( |
| Sized_relobj<32, big_endian>* object, |
| unsigned int r_type) |
| { |
| gold_error(_("%s: unsupported reloc %u against local symbol"), |
| object->name().c_str(), r_type); |
| } |
| |
| // We are about to emit a dynamic relocation of type R_TYPE. If the |
| // dynamic linker does not support it, issue an error. The GNU linker |
| // only issues a non-PIC error for an allocated read-only section. |
| // Here we know the section is allocated, but we don't know that it is |
| // read-only. But we check for all the relocation types which the |
| // glibc dynamic linker supports, so it seems appropriate to issue an |
| // error even if the section is not read-only. |
| |
| template<bool big_endian> |
| void |
| Target_arm<big_endian>::Scan::check_non_pic(Relobj* object, |
| unsigned int r_type) |
| { |
| switch (r_type) |
| { |
| // These are the relocation types supported by glibc for ARM. |
| case elfcpp::R_ARM_RELATIVE: |
| case elfcpp::R_ARM_COPY: |
| case elfcpp::R_ARM_GLOB_DAT: |
| case elfcpp::R_ARM_JUMP_SLOT: |
| case elfcpp::R_ARM_ABS32: |
| case elfcpp::R_ARM_PC24: |
| // FIXME: The following 3 types are not supported by Android's dynamic |
| // linker. |
| case elfcpp::R_ARM_TLS_DTPMOD32: |
| case elfcpp::R_ARM_TLS_DTPOFF32: |
| case elfcpp::R_ARM_TLS_TPOFF32: |
| return; |
| |
| default: |
| // This prevents us from issuing more than one error per reloc |
| // section. But we can still wind up issuing more than one |
| // error per object file. |
| if (this->issued_non_pic_error_) |
| return; |
| object->error(_("requires unsupported dynamic reloc; " |
| "recompile with -fPIC")); |
| this->issued_non_pic_error_ = true; |
| return; |
| |
| case elfcpp::R_ARM_NONE: |
| gold_unreachable(); |
| } |
| } |
| |
| // Scan a relocation for a local symbol. |
| // FIXME: This only handles a subset of relocation types used by Android |
| // on ARM v5te devices. |
| |
| template<bool big_endian> |
| inline void |
| Target_arm<big_endian>::Scan::local(const General_options&, |
| Symbol_table* symtab, |
| Layout* layout, |
| Target_arm* target, |
| Sized_relobj<32, big_endian>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, big_endian>& reloc, |
| unsigned int r_type, |
| const elfcpp::Sym<32, big_endian>&) |
| { |
| r_type = get_real_reloc_type(r_type); |
| switch (r_type) |
| { |
| case elfcpp::R_ARM_NONE: |
| break; |
| |
| case elfcpp::R_ARM_ABS32: |
| // If building a shared library (or a position-independent |
| // executable), we need to create a dynamic relocation for |
| // this location. The relocation applied at link time will |
| // apply the link-time value, so we flag the location with |
| // an R_ARM_RELATIVE relocation so the dynamic loader can |
| // relocate it easily. |
| if (parameters->options().output_is_position_independent()) |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| // If we are to add more other reloc types than R_ARM_ABS32, |
| // we need to add check_non_pic(object, r_type) here. |
| rel_dyn->add_local_relative(object, r_sym, elfcpp::R_ARM_RELATIVE, |
| output_section, data_shndx, |
| reloc.get_r_offset()); |
| } |
| break; |
| |
| case elfcpp::R_ARM_REL32: |
| case elfcpp::R_ARM_THM_CALL: |
| case elfcpp::R_ARM_CALL: |
| case elfcpp::R_ARM_PREL31: |
| case elfcpp::R_ARM_JUMP24: |
| case elfcpp::R_ARM_PLT32: |
| break; |
| |
| case elfcpp::R_ARM_GOTOFF32: |
| // We need a GOT section: |
| target->got_section(symtab, layout); |
| break; |
| |
| case elfcpp::R_ARM_BASE_PREL: |
| // FIXME: What about this? |
| break; |
| |
| case elfcpp::R_ARM_GOT_BREL: |
| { |
| // The symbol requires a GOT entry. |
| Output_data_got<32, big_endian>* got = |
| target->got_section(symtab, layout); |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| if (got->add_local(object, r_sym, GOT_TYPE_STANDARD)) |
| { |
| // If we are generating a shared object, we need to add a |
| // dynamic RELATIVE relocation for this symbol's GOT entry. |
| if (parameters->options().output_is_position_independent()) |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| rel_dyn->add_local_relative( |
| object, r_sym, elfcpp::R_ARM_RELATIVE, got, |
| object->local_got_offset(r_sym, GOT_TYPE_STANDARD)); |
| } |
| } |
| } |
| break; |
| |
| case elfcpp::R_ARM_TARGET1: |
| // This should have been mapped to another type already. |
| // Fall through. |
| case elfcpp::R_ARM_COPY: |
| case elfcpp::R_ARM_GLOB_DAT: |
| case elfcpp::R_ARM_JUMP_SLOT: |
| case elfcpp::R_ARM_RELATIVE: |
| // These are relocations which should only be seen by the |
| // dynamic linker, and should never be seen here. |
| gold_error(_("%s: unexpected reloc %u in object file"), |
| object->name().c_str(), r_type); |
| break; |
| |
| default: |
| unsupported_reloc_local(object, r_type); |
| break; |
| } |
| } |
| |
| // Report an unsupported relocation against a global symbol. |
| |
| template<bool big_endian> |
| void |
| Target_arm<big_endian>::Scan::unsupported_reloc_global( |
| Sized_relobj<32, big_endian>* object, |
| unsigned int r_type, |
| Symbol* gsym) |
| { |
| gold_error(_("%s: unsupported reloc %u against global symbol %s"), |
| object->name().c_str(), r_type, gsym->demangled_name().c_str()); |
| } |
| |
| // Scan a relocation for a global symbol. |
| // FIXME: This only handles a subset of relocation types used by Android |
| // on ARM v5te devices. |
| |
| template<bool big_endian> |
| inline void |
| Target_arm<big_endian>::Scan::global(const General_options&, |
| Symbol_table* symtab, |
| Layout* layout, |
| Target_arm* target, |
| Sized_relobj<32, big_endian>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, big_endian>& reloc, |
| unsigned int r_type, |
| Symbol* gsym) |
| { |
| r_type = get_real_reloc_type(r_type); |
| switch (r_type) |
| { |
| case elfcpp::R_ARM_NONE: |
| break; |
| |
| case elfcpp::R_ARM_ABS32: |
| { |
| // Make a dynamic relocation if necessary. |
| if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF)) |
| { |
| if (target->may_need_copy_reloc(gsym)) |
| { |
| target->copy_reloc(symtab, layout, object, |
| data_shndx, output_section, gsym, reloc); |
| } |
| else if (gsym->can_use_relative_reloc(false)) |
| { |
| // If we are to add more other reloc types than R_ARM_ABS32, |
| // we need to add check_non_pic(object, r_type) here. |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_global_relative(gsym, elfcpp::R_ARM_RELATIVE, |
| output_section, object, |
| data_shndx, reloc.get_r_offset()); |
| } |
| else |
| { |
| // If we are to add more other reloc types than R_ARM_ABS32, |
| // we need to add check_non_pic(object, r_type) here. |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_global(gsym, r_type, output_section, object, |
| data_shndx, reloc.get_r_offset()); |
| } |
| } |
| } |
| break; |
| |
| case elfcpp::R_ARM_REL32: |
| case elfcpp::R_ARM_PREL31: |
| { |
| // Make a dynamic relocation if necessary. |
| int flags = Symbol::NON_PIC_REF; |
| if (gsym->needs_dynamic_reloc(flags)) |
| { |
| if (target->may_need_copy_reloc(gsym)) |
| { |
| target->copy_reloc(symtab, layout, object, |
| data_shndx, output_section, gsym, reloc); |
| } |
| else |
| { |
| check_non_pic(object, r_type); |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_global(gsym, r_type, output_section, object, |
| data_shndx, reloc.get_r_offset()); |
| } |
| } |
| } |
| break; |
| |
| case elfcpp::R_ARM_JUMP24: |
| case elfcpp::R_ARM_THM_CALL: |
| case elfcpp::R_ARM_CALL: |
| { |
| if (Target_arm<big_endian>::Scan::symbol_needs_plt_entry(gsym)) |
| target->make_plt_entry(symtab, layout, gsym); |
| // Make a dynamic relocation if necessary. |
| int flags = Symbol::NON_PIC_REF; |
| if (gsym->type() == elfcpp::STT_FUNC |
| || gsym->type() == elfcpp::STT_ARM_TFUNC) |
| flags |= Symbol::FUNCTION_CALL; |
| if (gsym->needs_dynamic_reloc(flags)) |
| { |
| if (target->may_need_copy_reloc(gsym)) |
| { |
| target->copy_reloc(symtab, layout, object, |
| data_shndx, output_section, gsym, |
| reloc); |
| } |
| else |
| { |
| check_non_pic(object, r_type); |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_global(gsym, r_type, output_section, object, |
| data_shndx, reloc.get_r_offset()); |
| } |
| } |
| } |
| break; |
| |
| case elfcpp::R_ARM_PLT32: |
| // If the symbol is fully resolved, this is just a relative |
| // local reloc. Otherwise we need a PLT entry. |
| if (gsym->final_value_is_known()) |
| break; |
| // If building a shared library, we can also skip the PLT entry |
| // if the symbol is defined in the output file and is protected |
| // or hidden. |
| if (gsym->is_defined() |
| && !gsym->is_from_dynobj() |
| && !gsym->is_preemptible()) |
| break; |
| target->make_plt_entry(symtab, layout, gsym); |
| break; |
| |
| case elfcpp::R_ARM_GOTOFF32: |
| // We need a GOT section. |
| target->got_section(symtab, layout); |
| break; |
| |
| case elfcpp::R_ARM_BASE_PREL: |
| // FIXME: What about this? |
| break; |
| |
| case elfcpp::R_ARM_GOT_BREL: |
| { |
| // The symbol requires a GOT entry. |
| Output_data_got<32, big_endian>* got = |
| target->got_section(symtab, layout); |
| if (gsym->final_value_is_known()) |
| got->add_global(gsym, GOT_TYPE_STANDARD); |
| else |
| { |
| // If this symbol is not fully resolved, we need to add a |
| // GOT entry with a dynamic relocation. |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| if (gsym->is_from_dynobj() |
| || gsym->is_undefined() |
| || gsym->is_preemptible()) |
| got->add_global_with_rel(gsym, GOT_TYPE_STANDARD, |
| rel_dyn, elfcpp::R_ARM_GLOB_DAT); |
| else |
| { |
| if (got->add_global(gsym, GOT_TYPE_STANDARD)) |
| rel_dyn->add_global_relative( |
| gsym, elfcpp::R_ARM_RELATIVE, got, |
| gsym->got_offset(GOT_TYPE_STANDARD)); |
| } |
| } |
| } |
| break; |
| |
| case elfcpp::R_ARM_TARGET1: |
| // This should have been mapped to another type already. |
| // Fall through. |
| case elfcpp::R_ARM_COPY: |
| case elfcpp::R_ARM_GLOB_DAT: |
| case elfcpp::R_ARM_JUMP_SLOT: |
| case elfcpp::R_ARM_RELATIVE: |
| // These are relocations which should only be seen by the |
| // dynamic linker, and should never be seen here. |
| gold_error(_("%s: unexpected reloc %u in object file"), |
| object->name().c_str(), r_type); |
| break; |
| |
| default: |
| unsupported_reloc_global(object, r_type, gsym); |
| break; |
| } |
| } |
| |
| // Process relocations for gc. |
| |
| template<bool big_endian> |
| void |
| Target_arm<big_endian>::gc_process_relocs(const General_options& options, |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<32, big_endian>* object, |
| unsigned int data_shndx, |
| unsigned int, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols) |
| { |
| typedef Target_arm<big_endian> Arm; |
| typedef typename Target_arm<big_endian>::Scan Scan; |
| |
| gold::gc_process_relocs<32, big_endian, Arm, elfcpp::SHT_REL, Scan>( |
| options, |
| symtab, |
| layout, |
| this, |
| object, |
| data_shndx, |
| prelocs, |
| reloc_count, |
| output_section, |
| needs_special_offset_handling, |
| local_symbol_count, |
| plocal_symbols); |
| } |
| |
| // Scan relocations for a section. |
| |
| template<bool big_endian> |
| void |
| Target_arm<big_endian>::scan_relocs(const General_options& options, |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<32, big_endian>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols) |
| { |
| typedef typename Target_arm<big_endian>::Scan Scan; |
| if (sh_type == elfcpp::SHT_RELA) |
| { |
| gold_error(_("%s: unsupported RELA reloc section"), |
| object->name().c_str()); |
| return; |
| } |
| |
| gold::scan_relocs<32, big_endian, Target_arm, elfcpp::SHT_REL, Scan>( |
| options, |
| symtab, |
| layout, |
| this, |
| object, |
| data_shndx, |
| prelocs, |
| reloc_count, |
| output_section, |
| needs_special_offset_handling, |
| local_symbol_count, |
| plocal_symbols); |
| } |
| |
| // Finalize the sections. |
| |
| template<bool big_endian> |
| void |
| Target_arm<big_endian>::do_finalize_sections(Layout* layout) |
| { |
| // Fill in some more dynamic tags. |
| Output_data_dynamic* const odyn = layout->dynamic_data(); |
| if (odyn != NULL) |
| { |
| if (this->got_plt_ != NULL) |
| odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_); |
| |
| if (this->plt_ != NULL) |
| { |
| const Output_data* od = this->plt_->rel_plt(); |
| odyn->add_section_size(elfcpp::DT_PLTRELSZ, od); |
| odyn->add_section_address(elfcpp::DT_JMPREL, od); |
| odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL); |
| } |
| |
| if (this->rel_dyn_ != NULL) |
| { |
| const Output_data* od = this->rel_dyn_; |
| odyn->add_section_address(elfcpp::DT_REL, od); |
| odyn->add_section_size(elfcpp::DT_RELSZ, od); |
| odyn->add_constant(elfcpp::DT_RELENT, |
| elfcpp::Elf_sizes<32>::rel_size); |
| } |
| |
| if (!parameters->options().shared()) |
| { |
| // The value of the DT_DEBUG tag is filled in by the dynamic |
| // linker at run time, and used by the debugger. |
| odyn->add_constant(elfcpp::DT_DEBUG, 0); |
| } |
| } |
| |
| // Emit any relocs we saved in an attempt to avoid generating COPY |
| // relocs. |
| if (this->copy_relocs_.any_saved_relocs()) |
| this->copy_relocs_.emit(this->rel_dyn_section(layout)); |
| |
| // For the ARM target, we need to add a PT_ARM_EXIDX segment for |
| // the .ARM.exidx section. |
| if (!layout->script_options()->saw_phdrs_clause() |
| && !parameters->options().relocatable()) |
| { |
| Output_section* exidx_section = |
| layout->find_output_section(".ARM.exidx"); |
| |
| if (exidx_section != NULL |
| && exidx_section->type() == elfcpp::SHT_ARM_EXIDX) |
| { |
| gold_assert(layout->find_output_segment(elfcpp::PT_ARM_EXIDX, 0, 0) |
| == NULL); |
| Output_segment* exidx_segment = |
| layout->make_output_segment(elfcpp::PT_ARM_EXIDX, elfcpp::PF_R); |
| exidx_segment->add_output_section(exidx_section, elfcpp::PF_R); |
| } |
| } |
| } |
| |
| // Return whether a direct absolute static relocation needs to be applied. |
| // In cases where Scan::local() or Scan::global() has created |
| // a dynamic relocation other than R_ARM_RELATIVE, the addend |
| // of the relocation is carried in the data, and we must not |
| // apply the static relocation. |
| |
| template<bool big_endian> |
| inline bool |
| Target_arm<big_endian>::Relocate::should_apply_static_reloc( |
| const Sized_symbol<32>* gsym, |
| int ref_flags, |
| bool is_32bit, |
| Output_section* output_section) |
| { |
| // If the output section is not allocated, then we didn't call |
| // scan_relocs, we didn't create a dynamic reloc, and we must apply |
| // the reloc here. |
| if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0) |
| return true; |
| |
| // For local symbols, we will have created a non-RELATIVE dynamic |
| // relocation only if (a) the output is position independent, |
| // (b) the relocation is absolute (not pc- or segment-relative), and |
| // (c) the relocation is not 32 bits wide. |
| if (gsym == NULL) |
| return !(parameters->options().output_is_position_independent() |
| && (ref_flags & Symbol::ABSOLUTE_REF) |
| && !is_32bit); |
| |
| // For global symbols, we use the same helper routines used in the |
| // scan pass. If we did not create a dynamic relocation, or if we |
| // created a RELATIVE dynamic relocation, we should apply the static |
| // relocation. |
| bool has_dyn = gsym->needs_dynamic_reloc(ref_flags); |
| bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF) |
| && gsym->can_use_relative_reloc(ref_flags |
| & Symbol::FUNCTION_CALL); |
| return !has_dyn || is_rel; |
| } |
| |
| // Perform a relocation. |
| |
| template<bool big_endian> |
| inline bool |
| Target_arm<big_endian>::Relocate::relocate( |
| const Relocate_info<32, big_endian>* relinfo, |
| Target_arm* target, |
| Output_section *output_section, |
| size_t relnum, |
| const elfcpp::Rel<32, big_endian>& rel, |
| unsigned int r_type, |
| const Sized_symbol<32>* gsym, |
| const Symbol_value<32>* psymval, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr address, |
| section_size_type /* view_size */ ) |
| { |
| typedef Arm_relocate_functions<big_endian> Arm_relocate_functions; |
| |
| r_type = get_real_reloc_type(r_type); |
| |
| // If this the symbol may be a Thumb function, set thumb bit to 1. |
| bool has_thumb_bit = ((gsym != NULL) |
| && (gsym->type() == elfcpp::STT_FUNC |
| || gsym->type() == elfcpp::STT_ARM_TFUNC)); |
| |
| // Pick the value to use for symbols defined in shared objects. |
| Symbol_value<32> symval; |
| if (gsym != NULL |
| && gsym->use_plt_offset(reloc_is_non_pic(r_type))) |
| { |
| symval.set_output_value(target->plt_section()->address() |
| + gsym->plt_offset()); |
| psymval = &symval; |
| has_thumb_bit = 0; |
| } |
| |
| const Sized_relobj<32, big_endian>* object = relinfo->object; |
| |
| // Get the GOT offset if needed. |
| // The GOT pointer points to the end of the GOT section. |
| // We need to subtract the size of the GOT section to get |
| // the actual offset to use in the relocation. |
| bool have_got_offset = false; |
| unsigned int got_offset = 0; |
| switch (r_type) |
| { |
| case elfcpp::R_ARM_GOT_BREL: |
| if (gsym != NULL) |
| { |
| gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD)); |
| got_offset = (gsym->got_offset(GOT_TYPE_STANDARD) |
| - target->got_size()); |
| } |
| else |
| { |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); |
| gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD)); |
| got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD) |
| - target->got_size()); |
| } |
| have_got_offset = true; |
| break; |
| |
| default: |
| break; |
| } |
| |
| typename Arm_relocate_functions::Status reloc_status = |
| Arm_relocate_functions::STATUS_OKAY; |
| switch (r_type) |
| { |
| case elfcpp::R_ARM_NONE: |
| break; |
| |
| case elfcpp::R_ARM_ABS32: |
| if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true, |
| output_section)) |
| reloc_status = Arm_relocate_functions::abs32(view, object, psymval, |
| has_thumb_bit); |
| break; |
| |
| case elfcpp::R_ARM_REL32: |
| reloc_status = Arm_relocate_functions::rel32(view, object, psymval, |
| address, has_thumb_bit); |
| break; |
| |
| case elfcpp::R_ARM_THM_CALL: |
| reloc_status = Arm_relocate_functions::thm_call(view, object, psymval, |
| address, has_thumb_bit); |
| break; |
| |
| case elfcpp::R_ARM_GOTOFF32: |
| { |
| elfcpp::Elf_types<32>::Elf_Addr got_origin; |
| got_origin = target->got_plt_section()->address(); |
| reloc_status = Arm_relocate_functions::rel32(view, object, psymval, |
| got_origin, has_thumb_bit); |
| } |
| break; |
| |
| case elfcpp::R_ARM_BASE_PREL: |
| { |
| uint32_t origin; |
| // Get the addressing origin of the output segment defining the |
| // symbol gsym (AAELF 4.6.1.2 Relocation types) |
| gold_assert(gsym != NULL); |
| if (gsym->source() == Symbol::IN_OUTPUT_SEGMENT) |
| origin = gsym->output_segment()->vaddr(); |
| else if (gsym->source () == Symbol::IN_OUTPUT_DATA) |
| origin = gsym->output_data()->address(); |
| else |
| { |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("cannot find origin of R_ARM_BASE_PREL")); |
| return true; |
| } |
| reloc_status = Arm_relocate_functions::base_prel(view, origin, address); |
| } |
| break; |
| |
| case elfcpp::R_ARM_GOT_BREL: |
| gold_assert(have_got_offset); |
| reloc_status = Arm_relocate_functions::got_brel(view, got_offset); |
| break; |
| |
| case elfcpp::R_ARM_PLT32: |
| gold_assert(gsym == NULL |
| || gsym->has_plt_offset() |
| || gsym->final_value_is_known() |
| || (gsym->is_defined() |
| && !gsym->is_from_dynobj() |
| && !gsym->is_preemptible())); |
| reloc_status = Arm_relocate_functions::plt32(view, object, psymval, |
| address, has_thumb_bit); |
| break; |
| |
| case elfcpp::R_ARM_CALL: |
| reloc_status = Arm_relocate_functions::call(view, object, psymval, |
| address, has_thumb_bit); |
| break; |
| |
| case elfcpp::R_ARM_JUMP24: |
| reloc_status = Arm_relocate_functions::jump24(view, object, psymval, |
| address, has_thumb_bit); |
| break; |
| |
| case elfcpp::R_ARM_PREL31: |
| reloc_status = Arm_relocate_functions::prel31(view, object, psymval, |
| address, has_thumb_bit); |
| break; |
| |
| case elfcpp::R_ARM_TARGET1: |
| // This should have been mapped to another type already. |
| // Fall through. |
| case elfcpp::R_ARM_COPY: |
| case elfcpp::R_ARM_GLOB_DAT: |
| case elfcpp::R_ARM_JUMP_SLOT: |
| case elfcpp::R_ARM_RELATIVE: |
| // These are relocations which should only be seen by the |
| // dynamic linker, and should never be seen here. |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("unexpected reloc %u in object file"), |
| r_type); |
| break; |
| |
| default: |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("unsupported reloc %u"), |
| r_type); |
| break; |
| } |
| |
| // Report any errors. |
| switch (reloc_status) |
| { |
| case Arm_relocate_functions::STATUS_OKAY: |
| break; |
| case Arm_relocate_functions::STATUS_OVERFLOW: |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("relocation overflow in relocation %u"), |
| r_type); |
| break; |
| case Arm_relocate_functions::STATUS_BAD_RELOC: |
| gold_error_at_location( |
| relinfo, |
| relnum, |
| rel.get_r_offset(), |
| _("unexpected opcode while processing relocation %u"), |
| r_type); |
| break; |
| default: |
| gold_unreachable(); |
| } |
| |
| return true; |
| } |
| |
| // Relocate section data. |
| |
| template<bool big_endian> |
| void |
| Target_arm<big_endian>::relocate_section( |
| const Relocate_info<32, big_endian>* relinfo, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr address, |
| section_size_type view_size) |
| { |
| typedef typename Target_arm<big_endian>::Relocate Arm_relocate; |
| gold_assert(sh_type == elfcpp::SHT_REL); |
| |
| gold::relocate_section<32, big_endian, Target_arm, elfcpp::SHT_REL, |
| Arm_relocate>( |
| relinfo, |
| this, |
| prelocs, |
| reloc_count, |
| output_section, |
| needs_special_offset_handling, |
| view, |
| address, |
| view_size); |
| } |
| |
| // Return the size of a relocation while scanning during a relocatable |
| // link. |
| |
| template<bool big_endian> |
| unsigned int |
| Target_arm<big_endian>::Relocatable_size_for_reloc::get_size_for_reloc( |
| unsigned int r_type, |
| Relobj* object) |
| { |
| r_type = get_real_reloc_type(r_type); |
| switch (r_type) |
| { |
| case elfcpp::R_ARM_NONE: |
| return 0; |
| |
| case elfcpp::R_ARM_ABS32: |
| case elfcpp::R_ARM_REL32: |
| case elfcpp::R_ARM_THM_CALL: |
| case elfcpp::R_ARM_GOTOFF32: |
| case elfcpp::R_ARM_BASE_PREL: |
| case elfcpp::R_ARM_GOT_BREL: |
| case elfcpp::R_ARM_PLT32: |
| case elfcpp::R_ARM_CALL: |
| case elfcpp::R_ARM_JUMP24: |
| case elfcpp::R_ARM_PREL31: |
| return 4; |
| |
| case elfcpp::R_ARM_TARGET1: |
| // This should have been mapped to another type already. |
| // Fall through. |
| case elfcpp::R_ARM_COPY: |
| case elfcpp::R_ARM_GLOB_DAT: |
| case elfcpp::R_ARM_JUMP_SLOT: |
| case elfcpp::R_ARM_RELATIVE: |
| // These are relocations which should only be seen by the |
| // dynamic linker, and should never be seen here. |
| gold_error(_("%s: unexpected reloc %u in object file"), |
| object->name().c_str(), r_type); |
| return 0; |
| |
| default: |
| object->error(_("unsupported reloc %u in object file"), r_type); |
| return 0; |
| } |
| } |
| |
| // Scan the relocs during a relocatable link. |
| |
| template<bool big_endian> |
| void |
| Target_arm<big_endian>::scan_relocatable_relocs( |
| const General_options& options, |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<32, big_endian>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols, |
| Relocatable_relocs* rr) |
| { |
| gold_assert(sh_type == elfcpp::SHT_REL); |
| |
| typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL, |
| Relocatable_size_for_reloc> Scan_relocatable_relocs; |
| |
| gold::scan_relocatable_relocs<32, big_endian, elfcpp::SHT_REL, |
| Scan_relocatable_relocs>( |
| options, |
| symtab, |
| layout, |
| object, |
| data_shndx, |
| prelocs, |
| reloc_count, |
| output_section, |
| needs_special_offset_handling, |
| local_symbol_count, |
| plocal_symbols, |
| rr); |
| } |
| |
| // Relocate a section during a relocatable link. |
| |
| template<bool big_endian> |
| void |
| Target_arm<big_endian>::relocate_for_relocatable( |
| const Relocate_info<32, big_endian>* relinfo, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| off_t offset_in_output_section, |
| const Relocatable_relocs* rr, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr view_address, |
| section_size_type view_size, |
| unsigned char* reloc_view, |
| section_size_type reloc_view_size) |
| { |
| gold_assert(sh_type == elfcpp::SHT_REL); |
| |
| gold::relocate_for_relocatable<32, big_endian, elfcpp::SHT_REL>( |
| relinfo, |
| prelocs, |
| reloc_count, |
| output_section, |
| offset_in_output_section, |
| rr, |
| view, |
| view_address, |
| view_size, |
| reloc_view, |
| reloc_view_size); |
| } |
| |
| // Return the value to use for a dynamic symbol which requires special |
| // treatment. This is how we support equality comparisons of function |
| // pointers across shared library boundaries, as described in the |
| // processor specific ABI supplement. |
| |
| template<bool big_endian> |
| uint64_t |
| Target_arm<big_endian>::do_dynsym_value(const Symbol* gsym) const |
| { |
| gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset()); |
| return this->plt_section()->address() + gsym->plt_offset(); |
| } |
| |
| // Map platform-specific relocs to real relocs |
| // |
| template<bool big_endian> |
| unsigned int |
| Target_arm<big_endian>::get_real_reloc_type (unsigned int r_type) |
| { |
| switch (r_type) |
| { |
| case elfcpp::R_ARM_TARGET1: |
| // This is either R_ARM_ABS32 or R_ARM_REL32; |
| return elfcpp::R_ARM_ABS32; |
| |
| case elfcpp::R_ARM_TARGET2: |
| // This can be any reloc type but ususally is R_ARM_GOT_PREL |
| return elfcpp::R_ARM_GOT_PREL; |
| |
| default: |
| return r_type; |
| } |
| } |
| |
| // The selector for arm object files. |
| |
| template<bool big_endian> |
| class Target_selector_arm : public Target_selector |
| { |
| public: |
| Target_selector_arm() |
| : Target_selector(elfcpp::EM_ARM, 32, big_endian, |
| (big_endian ? "elf32-bigarm" : "elf32-littlearm")) |
| { } |
| |
| Target* |
| do_instantiate_target() |
| { return new Target_arm<big_endian>(); } |
| }; |
| |
| Target_selector_arm<false> target_selector_arm; |
| Target_selector_arm<true> target_selector_armbe; |
| |
| } // End anonymous namespace. |