// arm.cc -- arm target support for gold. // Copyright 2009 Free Software Foundation, Inc. // Written by Doug Kwan based on the i386 code // by Ian Lance Taylor . // This file also contains borrowed and adapted code from // bfd/elf32-arm.c. // 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 #include #include #include #include #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" #include "gc.h" namespace { using namespace gold; template class Output_data_plt_arm; template class Stub_table; template class Arm_input_section; template class Arm_output_section; template class Arm_relobj; template class Target_arm; // For convenience. typedef elfcpp::Elf_types<32>::Elf_Addr Arm_address; // Maximum branch offsets for ARM, THUMB and THUMB2. const int32_t ARM_MAX_FWD_BRANCH_OFFSET = ((((1 << 23) - 1) << 2) + 8); const int32_t ARM_MAX_BWD_BRANCH_OFFSET = ((-((1 << 23) << 2)) + 8); const int32_t THM_MAX_FWD_BRANCH_OFFSET = ((1 << 22) -2 + 4); const int32_t THM_MAX_BWD_BRANCH_OFFSET = (-(1 << 22) + 4); const int32_t THM2_MAX_FWD_BRANCH_OFFSET = (((1 << 24) - 2) + 4); const int32_t THM2_MAX_BWD_BRANCH_OFFSET = (-(1 << 24) + 4); // 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_ABS32_NOI // R_ARM_ABS16 // R_ARM_ABS12 // R_ARM_ABS8 // R_ARM_THM_ABS5 // R_ARM_BASE_ABS // 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_GOT_PREL // R_ARM_PLT32 // R_ARM_CALL // R_ARM_JUMP24 // R_ARM_TARGET1 // R_ARM_PREL31 // R_ARM_ABS8 // R_ARM_MOVW_ABS_NC // R_ARM_MOVT_ABS // R_ARM_THM_MOVW_ABS_NC // R_ARM_THM_MOVT_ABS // R_ARM_MOVW_PREL_NC // R_ARM_MOVT_PREL // R_ARM_THM_MOVW_PREL_NC // R_ARM_THM_MOVT_PREL // // 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. // Instruction template class. This class is similar to the insn_sequence // struct in bfd/elf32-arm.c. class Insn_template { public: // Types of instruction templates. enum Type { THUMB16_TYPE = 1, THUMB32_TYPE, ARM_TYPE, DATA_TYPE }; // Factory methods to create instrunction templates in different formats. static const Insn_template thumb16_insn(uint32_t data) { return Insn_template(data, THUMB16_TYPE, elfcpp::R_ARM_NONE, 0); } // A bit of a hack. A Thumb conditional branch, in which the proper // condition is inserted when we build the stub. static const Insn_template thumb16_bcond_insn(uint32_t data) { return Insn_template(data, THUMB16_TYPE, elfcpp::R_ARM_NONE, 1); } static const Insn_template thumb32_insn(uint32_t data) { return Insn_template(data, THUMB32_TYPE, elfcpp::R_ARM_NONE, 0); } static const Insn_template thumb32_b_insn(uint32_t data, int reloc_addend) { return Insn_template(data, THUMB32_TYPE, elfcpp::R_ARM_THM_JUMP24, reloc_addend); } static const Insn_template arm_insn(uint32_t data) { return Insn_template(data, ARM_TYPE, elfcpp::R_ARM_NONE, 0); } static const Insn_template arm_rel_insn(unsigned data, int reloc_addend) { return Insn_template(data, ARM_TYPE, elfcpp::R_ARM_JUMP24, reloc_addend); } static const Insn_template data_word(unsigned data, unsigned int r_type, int reloc_addend) { return Insn_template(data, DATA_TYPE, r_type, reloc_addend); } // Accessors. This class is used for read-only objects so no modifiers // are provided. uint32_t data() const { return this->data_; } // Return the instruction sequence type of this. Type type() const { return this->type_; } // Return the ARM relocation type of this. unsigned int r_type() const { return this->r_type_; } int32_t reloc_addend() const { return this->reloc_addend_; } // Return size of instrunction template in bytes. size_t size() const; // Return byte-alignment of instrunction template. unsigned alignment() const; private: // We make the constructor private to ensure that only the factory // methods are used. inline Insn_template(unsigned data, Type type, unsigned int r_type, int reloc_addend) : data_(data), type_(type), r_type_(r_type), reloc_addend_(reloc_addend) { } // Instruction specific data. This is used to store information like // some of the instruction bits. uint32_t data_; // Instruction template type. Type type_; // Relocation type if there is a relocation or R_ARM_NONE otherwise. unsigned int r_type_; // Relocation addend. int32_t reloc_addend_; }; // Macro for generating code to stub types. One entry per long/short // branch stub #define DEF_STUBS \ DEF_STUB(long_branch_any_any) \ DEF_STUB(long_branch_v4t_arm_thumb) \ DEF_STUB(long_branch_thumb_only) \ DEF_STUB(long_branch_v4t_thumb_thumb) \ DEF_STUB(long_branch_v4t_thumb_arm) \ DEF_STUB(short_branch_v4t_thumb_arm) \ DEF_STUB(long_branch_any_arm_pic) \ DEF_STUB(long_branch_any_thumb_pic) \ DEF_STUB(long_branch_v4t_thumb_thumb_pic) \ DEF_STUB(long_branch_v4t_arm_thumb_pic) \ DEF_STUB(long_branch_v4t_thumb_arm_pic) \ DEF_STUB(long_branch_thumb_only_pic) \ DEF_STUB(a8_veneer_b_cond) \ DEF_STUB(a8_veneer_b) \ DEF_STUB(a8_veneer_bl) \ DEF_STUB(a8_veneer_blx) // Stub types. #define DEF_STUB(x) arm_stub_##x, typedef enum { arm_stub_none, DEF_STUBS // First reloc stub type. arm_stub_reloc_first = arm_stub_long_branch_any_any, // Last reloc stub type. arm_stub_reloc_last = arm_stub_long_branch_thumb_only_pic, // First Cortex-A8 stub type. arm_stub_cortex_a8_first = arm_stub_a8_veneer_b_cond, // Last Cortex-A8 stub type. arm_stub_cortex_a8_last = arm_stub_a8_veneer_blx, // Last stub type. arm_stub_type_last = arm_stub_a8_veneer_blx } Stub_type; #undef DEF_STUB // Stub template class. Templates are meant to be read-only objects. // A stub template for a stub type contains all read-only attributes // common to all stubs of the same type. class Stub_template { public: Stub_template(Stub_type, const Insn_template*, size_t); ~Stub_template() { } // Return stub type. Stub_type type() const { return this->type_; } // Return an array of instruction templates. const Insn_template* insns() const { return this->insns_; } // Return size of template in number of instructions. size_t insn_count() const { return this->insn_count_; } // Return size of template in bytes. size_t size() const { return this->size_; } // Return alignment of the stub template. unsigned alignment() const { return this->alignment_; } // Return whether entry point is in thumb mode. bool entry_in_thumb_mode() const { return this->entry_in_thumb_mode_; } // Return number of relocations in this template. size_t reloc_count() const { return this->relocs_.size(); } // Return index of the I-th instruction with relocation. size_t reloc_insn_index(size_t i) const { gold_assert(i < this->relocs_.size()); return this->relocs_[i].first; } // Return the offset of the I-th instruction with relocation from the // beginning of the stub. section_size_type reloc_offset(size_t i) const { gold_assert(i < this->relocs_.size()); return this->relocs_[i].second; } private: // This contains information about an instruction template with a relocation // and its offset from start of stub. typedef std::pair Reloc; // A Stub_template may not be copied. We want to share templates as much // as possible. Stub_template(const Stub_template&); Stub_template& operator=(const Stub_template&); // Stub type. Stub_type type_; // Points to an array of Insn_templates. const Insn_template* insns_; // Number of Insn_templates in insns_[]. size_t insn_count_; // Size of templated instructions in bytes. size_t size_; // Alignment of templated instructions. unsigned alignment_; // Flag to indicate if entry is in thumb mode. bool entry_in_thumb_mode_; // A table of reloc instruction indices and offsets. We can find these by // looking at the instruction templates but we pre-compute and then stash // them here for speed. std::vector relocs_; }; // // A class for code stubs. This is a base class for different type of // stubs used in the ARM target. // class Stub { private: static const section_offset_type invalid_offset = static_cast(-1); public: Stub(const Stub_template* stub_template) : stub_template_(stub_template), offset_(invalid_offset) { } virtual ~Stub() { } // Return the stub template. const Stub_template* stub_template() const { return this->stub_template_; } // Return offset of code stub from beginning of its containing stub table. section_offset_type offset() const { gold_assert(this->offset_ != invalid_offset); return this->offset_; } // Set offset of code stub from beginning of its containing stub table. void set_offset(section_offset_type offset) { this->offset_ = offset; } // Return the relocation target address of the i-th relocation in the // stub. This must be defined in a child class. Arm_address reloc_target(size_t i) { return this->do_reloc_target(i); } // Write a stub at output VIEW. BIG_ENDIAN select how a stub is written. void write(unsigned char* view, section_size_type view_size, bool big_endian) { this->do_write(view, view_size, big_endian); } protected: // This must be defined in the child class. virtual Arm_address do_reloc_target(size_t) = 0; // This must be defined in the child class. virtual void do_write(unsigned char*, section_size_type, bool) = 0; private: // Its template. const Stub_template* stub_template_; // Offset within the section of containing this stub. section_offset_type offset_; }; // Reloc stub class. These are stubs we use to fix up relocation because // of limited branch ranges. class Reloc_stub : public Stub { public: static const unsigned int invalid_index = static_cast(-1); // We assume we never jump to this address. static const Arm_address invalid_address = static_cast(-1); // Return destination address. Arm_address destination_address() const { gold_assert(this->destination_address_ != this->invalid_address); return this->destination_address_; } // Set destination address. void set_destination_address(Arm_address address) { gold_assert(address != this->invalid_address); this->destination_address_ = address; } // Reset destination address. void reset_destination_address() { this->destination_address_ = this->invalid_address; } // Determine stub type for a branch of a relocation of R_TYPE going // from BRANCH_ADDRESS to BRANCH_TARGET. If TARGET_IS_THUMB is set, // the branch target is a thumb instruction. TARGET is used for look // up ARM-specific linker settings. static Stub_type stub_type_for_reloc(unsigned int r_type, Arm_address branch_address, Arm_address branch_target, bool target_is_thumb); // Reloc_stub key. A key is logically a triplet of a stub type, a symbol // and an addend. Since we treat global and local symbol differently, we // use a Symbol object for a global symbol and a object-index pair for // a local symbol. class Key { public: // If SYMBOL is not null, this is a global symbol, we ignore RELOBJ and // R_SYM. Otherwise, this is a local symbol and RELOBJ must non-NULL // and R_SYM must not be invalid_index. Key(Stub_type stub_type, const Symbol* symbol, const Relobj* relobj, unsigned int r_sym, int32_t addend) : stub_type_(stub_type), addend_(addend) { if (symbol != NULL) { this->r_sym_ = Reloc_stub::invalid_index; this->u_.symbol = symbol; } else { gold_assert(relobj != NULL && r_sym != invalid_index); this->r_sym_ = r_sym; this->u_.relobj = relobj; } } ~Key() { } // Accessors: Keys are meant to be read-only object so no modifiers are // provided. // Return stub type. Stub_type stub_type() const { return this->stub_type_; } // Return the local symbol index or invalid_index. unsigned int r_sym() const { return this->r_sym_; } // Return the symbol if there is one. const Symbol* symbol() const { return this->r_sym_ == invalid_index ? this->u_.symbol : NULL; } // Return the relobj if there is one. const Relobj* relobj() const { return this->r_sym_ != invalid_index ? this->u_.relobj : NULL; } // Whether this equals to another key k. bool eq(const Key& k) const { return ((this->stub_type_ == k.stub_type_) && (this->r_sym_ == k.r_sym_) && ((this->r_sym_ != Reloc_stub::invalid_index) ? (this->u_.relobj == k.u_.relobj) : (this->u_.symbol == k.u_.symbol)) && (this->addend_ == k.addend_)); } // Return a hash value. size_t hash_value() const { return (this->stub_type_ ^ this->r_sym_ ^ gold::string_hash( (this->r_sym_ != Reloc_stub::invalid_index) ? this->u_.relobj->name().c_str() : this->u_.symbol->name()) ^ this->addend_); } // Functors for STL associative containers. struct hash { size_t operator()(const Key& k) const { return k.hash_value(); } }; struct equal_to { bool operator()(const Key& k1, const Key& k2) const { return k1.eq(k2); } }; // Name of key. This is mainly for debugging. std::string name() const; private: // Stub type. Stub_type stub_type_; // If this is a local symbol, this is the index in the defining object. // Otherwise, it is invalid_index for a global symbol. unsigned int r_sym_; // If r_sym_ is invalid index. This points to a global symbol. // Otherwise, this points a relobj. We used the unsized and target // independent Symbol and Relobj classes instead of Sized_symbol<32> and // Arm_relobj. This is done to avoid making the stub class a template // as most of the stub machinery is endianity-neutral. However, it // may require a bit of casting done by users of this class. union { const Symbol* symbol; const Relobj* relobj; } u_; // Addend associated with a reloc. int32_t addend_; }; protected: // Reloc_stubs are created via a stub factory. So these are protected. Reloc_stub(const Stub_template* stub_template) : Stub(stub_template), destination_address_(invalid_address) { } ~Reloc_stub() { } friend class Stub_factory; private: // Return the relocation target address of the i-th relocation in the // stub. Arm_address do_reloc_target(size_t i) { // All reloc stub have only one relocation. gold_assert(i == 0); return this->destination_address_; } // A template to implement do_write below. template void inline do_fixed_endian_write(unsigned char*, section_size_type); // Write a stub. void do_write(unsigned char* view, section_size_type view_size, bool big_endian); // Address of destination. Arm_address destination_address_; }; // Stub factory class. class Stub_factory { public: // Return the unique instance of this class. static const Stub_factory& get_instance() { static Stub_factory singleton; return singleton; } // Make a relocation stub. Reloc_stub* make_reloc_stub(Stub_type stub_type) const { gold_assert(stub_type >= arm_stub_reloc_first && stub_type <= arm_stub_reloc_last); return new Reloc_stub(this->stub_templates_[stub_type]); } private: // Constructor and destructor are protected since we only return a single // instance created in Stub_factory::get_instance(). Stub_factory(); // A Stub_factory may not be copied since it is a singleton. Stub_factory(const Stub_factory&); Stub_factory& operator=(Stub_factory&); // Stub templates. These are initialized in the constructor. const Stub_template* stub_templates_[arm_stub_type_last+1]; }; // A class to hold stubs for the ARM target. template class Stub_table : public Output_data { public: Stub_table(Arm_input_section* owner) : Output_data(), addralign_(1), owner_(owner), has_been_changed_(false), reloc_stubs_() { } ~Stub_table() { } // Owner of this stub table. Arm_input_section* owner() const { return this->owner_; } // Whether this stub table is empty. bool empty() const { return this->reloc_stubs_.empty(); } // Whether this has been changed. bool has_been_changed() const { return this->has_been_changed_; } // Set the has-been-changed flag. void set_has_been_changed(bool value) { this->has_been_changed_ = value; } // Return the current data size. off_t current_data_size() const { return this->current_data_size_for_child(); } // Add a STUB with using KEY. Caller is reponsible for avoid adding // if already a STUB with the same key has been added. void add_reloc_stub(Reloc_stub* stub, const Reloc_stub::Key& key); // Look up a relocation stub using KEY. Return NULL if there is none. Reloc_stub* find_reloc_stub(const Reloc_stub::Key& key) const { typename Reloc_stub_map::const_iterator p = this->reloc_stubs_.find(key); return (p != this->reloc_stubs_.end()) ? p->second : NULL; } // Relocate stubs in this stub table. void relocate_stubs(const Relocate_info<32, big_endian>*, Target_arm*, Output_section*, unsigned char*, Arm_address, section_size_type); protected: // Write out section contents. void do_write(Output_file*); // Return the required alignment. uint64_t do_addralign() const { return this->addralign_; } // Finalize data size. void set_final_data_size() { this->set_data_size(this->current_data_size_for_child()); } // Reset address and file offset. void do_reset_address_and_file_offset(); private: // Unordered map of stubs. typedef Unordered_map Reloc_stub_map; // Address alignment uint64_t addralign_; // Owner of this stub table. Arm_input_section* owner_; // This is set to true during relaxiong if the size of the stub table // has been changed. bool has_been_changed_; // The relocation stubs. Reloc_stub_map reloc_stubs_; }; // A class to wrap an ordinary input section containing executable code. template class Arm_input_section : public Output_relaxed_input_section { public: Arm_input_section(Relobj* relobj, unsigned int shndx) : Output_relaxed_input_section(relobj, shndx, 1), original_addralign_(1), original_size_(0), stub_table_(NULL) { } ~Arm_input_section() { } // Initialize. void init(); // Whether this is a stub table owner. bool is_stub_table_owner() const { return this->stub_table_ != NULL && this->stub_table_->owner() == this; } // Return the stub table. Stub_table* stub_table() const { return this->stub_table_; } // Set the stub_table. void set_stub_table(Stub_table* stub_table) { this->stub_table_ = stub_table; } // Downcast a base pointer to an Arm_input_section pointer. This is // not type-safe but we only use Arm_input_section not the base class. static Arm_input_section* as_arm_input_section(Output_relaxed_input_section* poris) { return static_cast*>(poris); } protected: // Write data to output file. void do_write(Output_file*); // Return required alignment of this. uint64_t do_addralign() const { if (this->is_stub_table_owner()) return std::max(this->stub_table_->addralign(), this->original_addralign_); else return this->original_addralign_; } // Finalize data size. void set_final_data_size(); // Reset address and file offset. void do_reset_address_and_file_offset(); // Output offset. bool do_output_offset(const Relobj* object, unsigned int shndx, section_offset_type offset, section_offset_type* poutput) const { if ((object == this->relobj()) && (shndx == this->shndx()) && (offset >= 0) && (convert_types(offset) <= this->original_size_)) { *poutput = offset; return true; } else return false; } private: // Copying is not allowed. Arm_input_section(const Arm_input_section&); Arm_input_section& operator=(const Arm_input_section&); // Address alignment of the original input section. uint64_t original_addralign_; // Section size of the original input section. uint64_t original_size_; // Stub table. Stub_table* stub_table_; }; // Arm output section class. This is defined mainly to add a number of // stub generation methods. template class Arm_output_section : public Output_section { public: Arm_output_section(const char* name, elfcpp::Elf_Word type, elfcpp::Elf_Xword flags) : Output_section(name, type, flags) { } ~Arm_output_section() { } // Group input sections for stub generation. void group_sections(section_size_type, bool, Target_arm*); // Downcast a base pointer to an Arm_output_section pointer. This is // not type-safe but we only use Arm_output_section not the base class. static Arm_output_section* as_arm_output_section(Output_section* os) { return static_cast*>(os); } private: // For convenience. typedef Output_section::Input_section Input_section; typedef Output_section::Input_section_list Input_section_list; // Create a stub group. void create_stub_group(Input_section_list::const_iterator, Input_section_list::const_iterator, Input_section_list::const_iterator, Target_arm*, std::vector*); }; // Arm_relobj class. template class Arm_relobj : public Sized_relobj<32, big_endian> { public: static const Arm_address invalid_address = static_cast(-1); Arm_relobj(const std::string& name, Input_file* input_file, off_t offset, const typename elfcpp::Ehdr<32, big_endian>& ehdr) : Sized_relobj<32, big_endian>(name, input_file, offset, ehdr), stub_tables_(), local_symbol_is_thumb_function_() { } ~Arm_relobj() { } // Return the stub table of the SHNDX-th section if there is one. Stub_table* stub_table(unsigned int shndx) const { gold_assert(shndx < this->stub_tables_.size()); return this->stub_tables_[shndx]; } // Set STUB_TABLE to be the stub_table of the SHNDX-th section. void set_stub_table(unsigned int shndx, Stub_table* stub_table) { gold_assert(shndx < this->stub_tables_.size()); this->stub_tables_[shndx] = stub_table; } // Whether a local symbol is a THUMB function. R_SYM is the symbol table // index. This is only valid after do_count_local_symbol is called. bool local_symbol_is_thumb_function(unsigned int r_sym) const { gold_assert(r_sym < this->local_symbol_is_thumb_function_.size()); return this->local_symbol_is_thumb_function_[r_sym]; } // Scan all relocation sections for stub generation. void scan_sections_for_stubs(Target_arm*, const Symbol_table*, const Layout*); // Convert regular input section with index SHNDX to a relaxed section. void convert_input_section_to_relaxed_section(unsigned shndx) { // The stubs have relocations and we need to process them after writing // out the stubs. So relocation now must follow section write. this->invalidate_section_offset(shndx); this->set_relocs_must_follow_section_writes(); } // Downcast a base pointer to an Arm_relobj pointer. This is // not type-safe but we only use Arm_relobj not the base class. static Arm_relobj* as_arm_relobj(Relobj* relobj) { return static_cast*>(relobj); } // Processor-specific flags in ELF file header. This is valid only after // reading symbols. elfcpp::Elf_Word processor_specific_flags() const { return this->processor_specific_flags_; } protected: // Post constructor setup. void do_setup() { // Call parent's setup method. Sized_relobj<32, big_endian>::do_setup(); // Initialize look-up tables. Stub_table_list empty_stub_table_list(this->shnum(), NULL); this->stub_tables_.swap(empty_stub_table_list); } // Count the local symbols. void do_count_local_symbols(Stringpool_template*, Stringpool_template*); void do_relocate_sections(const Symbol_table* symtab, const Layout* layout, const unsigned char* pshdrs, typename Sized_relobj<32, big_endian>::Views* pivews); // Read the symbol information. void do_read_symbols(Read_symbols_data* sd); private: // List of stub tables. typedef std::vector*> Stub_table_list; Stub_table_list stub_tables_; // Bit vector to tell if a local symbol is a thumb function or not. // This is only valid after do_count_local_symbol is called. std::vector local_symbol_is_thumb_function_; // processor-specific flags in ELF file header. elfcpp::Elf_Word processor_specific_flags_; }; // Arm_dynobj class. template class Arm_dynobj : public Sized_dynobj<32, big_endian> { public: Arm_dynobj(const std::string& name, Input_file* input_file, off_t offset, const elfcpp::Ehdr<32, big_endian>& ehdr) : Sized_dynobj<32, big_endian>(name, input_file, offset, ehdr), processor_specific_flags_(0) { } ~Arm_dynobj() { } // Downcast a base pointer to an Arm_relobj pointer. This is // not type-safe but we only use Arm_relobj not the base class. static Arm_dynobj* as_arm_dynobj(Dynobj* dynobj) { return static_cast*>(dynobj); } // Processor-specific flags in ELF file header. This is valid only after // reading symbols. elfcpp::Elf_Word processor_specific_flags() const { return this->processor_specific_flags_; } protected: // Read the symbol information. void do_read_symbols(Read_symbols_data* sd); private: // processor-specific flags in ELF file header. elfcpp::Elf_Word processor_specific_flags_; }; // Functor to read reloc addends during stub generation. template struct Stub_addend_reader { // Return the addend for a relocation of a particular type. Depending // on whether this is a REL or RELA relocation, read the addend from a // view or from a Reloc object. elfcpp::Elf_types<32>::Elf_Swxword operator()( unsigned int /* r_type */, const unsigned char* /* view */, const typename Reloc_types::Reloc& /* reloc */) const; }; // Specialized Stub_addend_reader for SHT_REL type relocation sections. template struct Stub_addend_reader { elfcpp::Elf_types<32>::Elf_Swxword operator()( unsigned int, const unsigned char*, const typename Reloc_types::Reloc&) const; }; // Specialized Stub_addend_reader for RELA type relocation sections. // We currently do not handle RELA type relocation sections but it is trivial // to implement the addend reader. This is provided for completeness and to // make it easier to add support for RELA relocation sections in the future. template struct Stub_addend_reader { elfcpp::Elf_types<32>::Elf_Swxword operator()( unsigned int, const unsigned char*, const typename Reloc_types::Reloc& reloc) const { return reloc.get_r_addend(); } }; // 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 static inline int32_t sign_extend(uint32_t bits) { gold_assert(no_bits >= 0 && no_bits <= 32); if (no_bits == 32) return static_cast(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(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 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(bits); return as_signed > max || as_signed < min; } // Detects overflow of an NO_BITS integer stored in a uint32_t when it // fits in the given number of bits as either a signed or unsigned value. // For example, has_signed_unsigned_overflow<8> would check // -128 <= bits <= 255 template static inline bool has_signed_unsigned_overflow(uint32_t bits) { gold_assert(no_bits >= 2 && no_bits <= 32); if (no_bits == 32) return false; int32_t max = static_cast((1U << no_bits) - 1); int32_t min = -(1 << (no_bits - 1)); int32_t as_signed = static_cast(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 class Target_arm : public Sized_target<32, big_endian> { public: typedef Output_data_reloc Reloc_section; // When were are relocating a stub, we pass this as the relocation number. static const size_t fake_relnum_for_stubs = static_cast(-1); Target_arm(); // Whether we can use BLX. bool may_use_blx() const { return this->may_use_blx_; } // Set use-BLX flag. void set_may_use_blx(bool value) { this->may_use_blx_ = value; } // Whether we force PCI branch veneers. bool should_force_pic_veneer() const { return this->should_force_pic_veneer_; } // Set PIC veneer flag. void set_should_force_pic_veneer(bool value) { this->should_force_pic_veneer_ = value; } // Whether we use THUMB-2 instructions. bool using_thumb2() const { // FIXME: This should not hard-coded. return false; } // Whether we use THUMB/THUMB-2 instructions only. bool using_thumb_only() const { // FIXME: This should not hard-coded. return false; } // Whether we have an NOP instruction. If not, use mov r0, r0 instead. bool may_use_arm_nop() const { // FIXME: This should not hard-coded. return false; } // Whether we have THUMB-2 NOP.W instruction. bool may_use_thumb2_nop() const { // FIXME: This should not hard-coded. return false; } // Process the relocations to determine unreferenced sections for // garbage collection. void gc_process_relocs(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(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*, const Input_objects*); // 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, Arm_address view_address, section_size_type view_size, const Reloc_symbol_changes*); // Scan the relocs during a relocatable link. void scan_relocatable_relocs(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, Arm_address 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 unsigned int get_real_reloc_type (unsigned int r_type) const; // // Methods to support stub-generations. // // Return the stub factory const Stub_factory& stub_factory() const { return this->stub_factory_; } // Make a new Arm_input_section object. Arm_input_section* new_arm_input_section(Relobj*, unsigned int); // Find the Arm_input_section object corresponding to the SHNDX-th input // section of RELOBJ. Arm_input_section* find_arm_input_section(Relobj* relobj, unsigned int shndx) const; // Make a new Stub_table Stub_table* new_stub_table(Arm_input_section*); // Scan a section for stub generation. void scan_section_for_stubs(const Relocate_info<32, big_endian>*, unsigned int, const unsigned char*, size_t, Output_section*, bool, const unsigned char*, Arm_address, section_size_type); // Relocate a stub. void relocate_stub(Reloc_stub*, const Relocate_info<32, big_endian>*, Output_section*, unsigned char*, Arm_address, section_size_type); // Get the default ARM target. static Target_arm* default_target() { gold_assert(parameters->target().machine_code() == elfcpp::EM_ARM && parameters->target().is_big_endian() == big_endian); return static_cast*>( parameters->sized_target<32, big_endian>()); } // Whether relocation type uses LSB to distinguish THUMB addresses. static bool reloc_uses_thumb_bit(unsigned int r_type); protected: // Make an ELF object. Object* do_make_elf_object(const std::string&, Input_file*, off_t, const elfcpp::Ehdr<32, big_endian>& ehdr); Object* do_make_elf_object(const std::string&, Input_file*, off_t, const elfcpp::Ehdr<32, !big_endian>&) { gold_unreachable(); } Object* do_make_elf_object(const std::string&, Input_file*, off_t, const elfcpp::Ehdr<64, false>&) { gold_unreachable(); } Object* do_make_elf_object(const std::string&, Input_file*, off_t, const elfcpp::Ehdr<64, true>&) { gold_unreachable(); } // Make an output section. Output_section* do_make_output_section(const char* name, elfcpp::Elf_Word type, elfcpp::Elf_Xword flags) { return new Arm_output_section(name, type, flags); } void do_adjust_elf_header(unsigned char* view, int len) const; // We only need to generate stubs, and hence perform relaxation if we are // not doing relocatable linking. bool do_may_relax() const { return !parameters->options().relocatable(); } bool do_relax(int, const Input_objects*, Symbol_table*, Layout*); private: // The class which scans relocations. class Scan { public: Scan() : issued_non_pic_error_(false) { } inline void local(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(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*, Arm_address, 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: case elfcpp::R_ARM_THM_ABS5: case elfcpp::R_ARM_ABS8: case elfcpp::R_ARM_ABS12: case elfcpp::R_ARM_ABS16: case elfcpp::R_ARM_BASE_ABS: 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* 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 (gsym->type() != elfcpp::STT_ARM_TFUNC && gsym->may_need_copy_reloc()); } // 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)); } // Whether two EABI versions are compatible. static bool are_eabi_versions_compatible(elfcpp::Elf_Word v1, elfcpp::Elf_Word v2); // Merge processor-specific flags from input object and those in the ELF // header of the output. void merge_processor_specific_flags(const std::string&, elfcpp::Elf_Word); // // Methods to support stub-generations. // // Group input sections for stub generation. void group_sections(Layout*, section_size_type, bool); // Scan a relocation for stub generation. void scan_reloc_for_stub(const Relocate_info<32, big_endian>*, unsigned int, const Sized_symbol<32>*, unsigned int, const Symbol_value<32>*, elfcpp::Elf_types<32>::Elf_Swxword, Arm_address); // Scan a relocation section for stub. template void scan_reloc_section_for_stubs( const Relocate_info<32, big_endian>* relinfo, const unsigned char* prelocs, size_t reloc_count, Output_section* output_section, bool needs_special_offset_handling, const unsigned char* view, elfcpp::Elf_types<32>::Elf_Addr view_address, section_size_type); // 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 }; typedef typename std::vector*> Stub_table_list; // Map input section to Arm_input_section. typedef Unordered_map*, Input_section_specifier::hash, Input_section_specifier::equal_to> Arm_input_section_map; // The GOT section. Output_data_got<32, big_endian>* got_; // The PLT section. Output_data_plt_arm* 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 copy_relocs_; // Space for variables copied with a COPY reloc. Output_data_space* dynbss_; // Vector of Stub_tables created. Stub_table_list stub_tables_; // Stub factory. const Stub_factory &stub_factory_; // Whether R_ARM_TARGET1 maps to R_ARM_REL32 or R_ARM_ABS32. bool target1_is_rel_; // What R_ARM_TARGET2 maps to. It should be one of R_ARM_REL32, R_ARM_ABS32 // and R_ARM_GOT_PREL. unsigned int target2_reloc_; // Whether we can use BLX. bool may_use_blx_; // Whether we force PIC branch veneers. bool should_force_pic_veneer_; // Map for locating Arm_input_sections. Arm_input_section_map arm_input_section_map_; }; template const Target::Target_info Target_arm::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 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 This; // Encoding of imm16 argument for movt and movw ARM instructions // from ARM ARM: // // imm16 := imm4 | imm12 // // f e d c b a 9 8 7 6 5 4 3 2 1 0 f e d c b a 9 8 7 6 5 4 3 2 1 0 // +-------+---------------+-------+-------+-----------------------+ // | | |imm4 | |imm12 | // +-------+---------------+-------+-------+-----------------------+ // Extract the relocation addend from VAL based on the ARM // instruction encoding described above. static inline typename elfcpp::Swap<32, big_endian>::Valtype extract_arm_movw_movt_addend( typename elfcpp::Swap<32, big_endian>::Valtype val) { // According to the Elf ABI for ARM Architecture the immediate // field is sign-extended to form the addend. return utils::sign_extend<16>(((val >> 4) & 0xf000) | (val & 0xfff)); } // Insert X into VAL based on the ARM instruction encoding described // above. static inline typename elfcpp::Swap<32, big_endian>::Valtype insert_val_arm_movw_movt( typename elfcpp::Swap<32, big_endian>::Valtype val, typename elfcpp::Swap<32, big_endian>::Valtype x) { val &= 0xfff0f000; val |= x & 0x0fff; val |= (x & 0xf000) << 4; return val; } // Encoding of imm16 argument for movt and movw Thumb2 instructions // from ARM ARM: // // imm16 := imm4 | i | imm3 | imm8 // // f e d c b a 9 8 7 6 5 4 3 2 1 0 f e d c b a 9 8 7 6 5 4 3 2 1 0 // +---------+-+-----------+-------++-+-----+-------+---------------+ // | |i| |imm4 || |imm3 | |imm8 | // +---------+-+-----------+-------++-+-----+-------+---------------+ // Extract the relocation addend from VAL based on the Thumb2 // instruction encoding described above. static inline typename elfcpp::Swap<32, big_endian>::Valtype extract_thumb_movw_movt_addend( typename elfcpp::Swap<32, big_endian>::Valtype val) { // According to the Elf ABI for ARM Architecture the immediate // field is sign-extended to form the addend. return utils::sign_extend<16>(((val >> 4) & 0xf000) | ((val >> 15) & 0x0800) | ((val >> 4) & 0x0700) | (val & 0x00ff)); } // Insert X into VAL based on the Thumb2 instruction encoding // described above. static inline typename elfcpp::Swap<32, big_endian>::Valtype insert_val_thumb_movw_movt( typename elfcpp::Swap<32, big_endian>::Valtype val, typename elfcpp::Swap<32, big_endian>::Valtype x) { val &= 0xfbf08f00; val |= (x & 0xf000) << 4; val |= (x & 0x0800) << 15; val |= (x & 0x0700) << 4; val |= (x & 0x00ff); return val; } // Handle ARM long branches. static typename This::Status arm_branch_common(unsigned int, const Relocate_info<32, big_endian>*, unsigned char *, const Sized_symbol<32>*, const Arm_relobj*, unsigned int, const Symbol_value<32>*, Arm_address, Arm_address, bool); // Handle THUMB long branches. static typename This::Status thumb_branch_common(unsigned int, const Relocate_info<32, big_endian>*, unsigned char *, const Sized_symbol<32>*, const Arm_relobj*, unsigned int, const Symbol_value<32>*, Arm_address, Arm_address, bool); public: // R_ARM_ABS8: S + A static inline typename This::Status abs8(unsigned char *view, const Sized_relobj<32, big_endian>* object, const Symbol_value<32>* psymval) { typedef typename elfcpp::Swap<8, big_endian>::Valtype Valtype; typedef typename elfcpp::Swap<32, big_endian>::Valtype Reltype; Valtype* wv = reinterpret_cast(view); Valtype val = elfcpp::Swap<8, big_endian>::readval(wv); Reltype addend = utils::sign_extend<8>(val); Reltype x = psymval->value(object, addend); val = utils::bit_select(val, x, 0xffU); elfcpp::Swap<8, big_endian>::writeval(wv, val); return (utils::has_signed_unsigned_overflow<8>(x) ? This::STATUS_OVERFLOW : This::STATUS_OKAY); } // R_ARM_THM_ABS5: S + A static inline typename This::Status thm_abs5(unsigned char *view, const Sized_relobj<32, big_endian>* object, const Symbol_value<32>* psymval) { typedef typename elfcpp::Swap<16, big_endian>::Valtype Valtype; typedef typename elfcpp::Swap<32, big_endian>::Valtype Reltype; Valtype* wv = reinterpret_cast(view); Valtype val = elfcpp::Swap<16, big_endian>::readval(wv); Reltype addend = (val & 0x7e0U) >> 6; Reltype x = psymval->value(object, addend); val = utils::bit_select(val, x << 6, 0x7e0U); elfcpp::Swap<16, big_endian>::writeval(wv, val); return (utils::has_overflow<5>(x) ? This::STATUS_OVERFLOW : This::STATUS_OKAY); } // R_ARM_ABS12: S + A static inline typename This::Status abs12(unsigned char *view, const Sized_relobj<32, big_endian>* object, const Symbol_value<32>* psymval) { typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; typedef typename elfcpp::Swap<32, big_endian>::Valtype Reltype; Valtype* wv = reinterpret_cast(view); Valtype val = elfcpp::Swap<32, big_endian>::readval(wv); Reltype addend = val & 0x0fffU; Reltype x = psymval->value(object, addend); val = utils::bit_select(val, x, 0x0fffU); elfcpp::Swap<32, big_endian>::writeval(wv, val); return (utils::has_overflow<12>(x) ? This::STATUS_OVERFLOW : This::STATUS_OKAY); } // R_ARM_ABS16: S + A static inline typename This::Status abs16(unsigned char *view, const Sized_relobj<32, big_endian>* object, const Symbol_value<32>* psymval) { typedef typename elfcpp::Swap<16, big_endian>::Valtype Valtype; typedef typename elfcpp::Swap<32, big_endian>::Valtype Reltype; Valtype* wv = reinterpret_cast(view); Valtype val = elfcpp::Swap<16, big_endian>::readval(wv); Reltype addend = utils::sign_extend<16>(val); Reltype x = psymval->value(object, addend); val = utils::bit_select(val, x, 0xffffU); elfcpp::Swap<16, big_endian>::writeval(wv, val); return (utils::has_signed_unsigned_overflow<16>(x) ? This::STATUS_OVERFLOW : This::STATUS_OKAY); } // 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, Arm_address thumb_bit) { typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast(view); Valtype addend = elfcpp::Swap<32, big_endian>::readval(wv); Valtype x = psymval->value(object, addend) | 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, Arm_address address, Arm_address thumb_bit) { typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast(view); Valtype addend = elfcpp::Swap<32, big_endian>::readval(wv); Valtype x = (psymval->value(object, addend) | 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(const Relocate_info<32, big_endian>* relinfo, unsigned char *view, const Sized_symbol<32>* gsym, const Arm_relobj* object, unsigned int r_sym, const Symbol_value<32>* psymval, Arm_address address, Arm_address thumb_bit, bool is_weakly_undefined_without_plt) { return thumb_branch_common(elfcpp::R_ARM_THM_CALL, relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); } // R_ARM_THM_JUMP24: (S + A) | T - P static inline typename This::Status thm_jump24(const Relocate_info<32, big_endian>* relinfo, unsigned char *view, const Sized_symbol<32>* gsym, const Arm_relobj* object, unsigned int r_sym, const Symbol_value<32>* psymval, Arm_address address, Arm_address thumb_bit, bool is_weakly_undefined_without_plt) { return thumb_branch_common(elfcpp::R_ARM_THM_JUMP24, relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); } // R_ARM_THM_XPC22: (S + A) | T - P static inline typename This::Status thm_xpc22(const Relocate_info<32, big_endian>* relinfo, unsigned char *view, const Sized_symbol<32>* gsym, const Arm_relobj* object, unsigned int r_sym, const Symbol_value<32>* psymval, Arm_address address, Arm_address thumb_bit, bool is_weakly_undefined_without_plt) { return thumb_branch_common(elfcpp::R_ARM_THM_XPC22, relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); } // R_ARM_BASE_PREL: B(S) + A - P static inline typename This::Status base_prel(unsigned char* view, Arm_address origin, Arm_address address) { Base::rel32(view, origin - address); return STATUS_OKAY; } // R_ARM_BASE_ABS: B(S) + A static inline typename This::Status base_abs(unsigned char* view, Arm_address origin) { Base::rel32(view, origin); 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_GOT_PREL: GOT(S) + A – P static inline typename This::Status got_prel(unsigned char* view, typename elfcpp::Swap<32, big_endian>::Valtype got_offset, Arm_address address) { Base::rel32(view, got_offset - address); return This::STATUS_OKAY; } // R_ARM_PLT32: (S + A) | T - P static inline typename This::Status plt32(const Relocate_info<32, big_endian>* relinfo, unsigned char *view, const Sized_symbol<32>* gsym, const Arm_relobj* object, unsigned int r_sym, const Symbol_value<32>* psymval, Arm_address address, Arm_address thumb_bit, bool is_weakly_undefined_without_plt) { return arm_branch_common(elfcpp::R_ARM_PLT32, relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); } // R_ARM_XPC25: (S + A) | T - P static inline typename This::Status xpc25(const Relocate_info<32, big_endian>* relinfo, unsigned char *view, const Sized_symbol<32>* gsym, const Arm_relobj* object, unsigned int r_sym, const Symbol_value<32>* psymval, Arm_address address, Arm_address thumb_bit, bool is_weakly_undefined_without_plt) { return arm_branch_common(elfcpp::R_ARM_XPC25, relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); } // R_ARM_CALL: (S + A) | T - P static inline typename This::Status call(const Relocate_info<32, big_endian>* relinfo, unsigned char *view, const Sized_symbol<32>* gsym, const Arm_relobj* object, unsigned int r_sym, const Symbol_value<32>* psymval, Arm_address address, Arm_address thumb_bit, bool is_weakly_undefined_without_plt) { return arm_branch_common(elfcpp::R_ARM_CALL, relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); } // R_ARM_JUMP24: (S + A) | T - P static inline typename This::Status jump24(const Relocate_info<32, big_endian>* relinfo, unsigned char *view, const Sized_symbol<32>* gsym, const Arm_relobj* object, unsigned int r_sym, const Symbol_value<32>* psymval, Arm_address address, Arm_address thumb_bit, bool is_weakly_undefined_without_plt) { return arm_branch_common(elfcpp::R_ARM_JUMP24, relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); } // 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, Arm_address address, Arm_address thumb_bit) { typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast(view); Valtype val = elfcpp::Swap<32, big_endian>::readval(wv); Valtype addend = utils::sign_extend<31>(val); Valtype x = (psymval->value(object, addend) | 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); } // R_ARM_MOVW_ABS_NC: (S + A) | T static inline typename This::Status movw_abs_nc(unsigned char *view, const Sized_relobj<32, big_endian>* object, const Symbol_value<32>* psymval, Arm_address thumb_bit) { typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast(view); Valtype val = elfcpp::Swap<32, big_endian>::readval(wv); Valtype addend = This::extract_arm_movw_movt_addend(val); Valtype x = psymval->value(object, addend) | thumb_bit; val = This::insert_val_arm_movw_movt(val, x); elfcpp::Swap<32, big_endian>::writeval(wv, val); return This::STATUS_OKAY; } // R_ARM_MOVT_ABS: S + A static inline typename This::Status movt_abs(unsigned char *view, const Sized_relobj<32, big_endian>* object, const Symbol_value<32>* psymval) { typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast(view); Valtype val = elfcpp::Swap<32, big_endian>::readval(wv); Valtype addend = This::extract_arm_movw_movt_addend(val); Valtype x = psymval->value(object, addend) >> 16; val = This::insert_val_arm_movw_movt(val, x); elfcpp::Swap<32, big_endian>::writeval(wv, val); return This::STATUS_OKAY; } // R_ARM_THM_MOVW_ABS_NC: S + A | T static inline typename This::Status thm_movw_abs_nc(unsigned char *view, const Sized_relobj<32, big_endian>* object, const Symbol_value<32>* psymval, Arm_address thumb_bit) { typedef typename elfcpp::Swap<16, big_endian>::Valtype Valtype; typedef typename elfcpp::Swap<32, big_endian>::Valtype Reltype; Valtype* wv = reinterpret_cast(view); Reltype val = ((elfcpp::Swap<16, big_endian>::readval(wv) << 16) | elfcpp::Swap<16, big_endian>::readval(wv + 1)); Reltype addend = extract_thumb_movw_movt_addend(val); Reltype x = psymval->value(object, addend) | thumb_bit; val = This::insert_val_thumb_movw_movt(val, x); elfcpp::Swap<16, big_endian>::writeval(wv, val >> 16); elfcpp::Swap<16, big_endian>::writeval(wv + 1, val & 0xffff); return This::STATUS_OKAY; } // R_ARM_THM_MOVT_ABS: S + A static inline typename This::Status thm_movt_abs(unsigned char *view, const Sized_relobj<32, big_endian>* object, const Symbol_value<32>* psymval) { typedef typename elfcpp::Swap<16, big_endian>::Valtype Valtype; typedef typename elfcpp::Swap<32, big_endian>::Valtype Reltype; Valtype* wv = reinterpret_cast(view); Reltype val = ((elfcpp::Swap<16, big_endian>::readval(wv) << 16) | elfcpp::Swap<16, big_endian>::readval(wv + 1)); Reltype addend = This::extract_thumb_movw_movt_addend(val); Reltype x = psymval->value(object, addend) >> 16; val = This::insert_val_thumb_movw_movt(val, x); elfcpp::Swap<16, big_endian>::writeval(wv, val >> 16); elfcpp::Swap<16, big_endian>::writeval(wv + 1, val & 0xffff); return This::STATUS_OKAY; } // R_ARM_MOVW_PREL_NC: (S + A) | T - P static inline typename This::Status movw_prel_nc(unsigned char *view, const Sized_relobj<32, big_endian>* object, const Symbol_value<32>* psymval, Arm_address address, Arm_address thumb_bit) { typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast(view); Valtype val = elfcpp::Swap<32, big_endian>::readval(wv); Valtype addend = This::extract_arm_movw_movt_addend(val); Valtype x = (psymval->value(object, addend) | thumb_bit) - address; val = This::insert_val_arm_movw_movt(val, x); elfcpp::Swap<32, big_endian>::writeval(wv, val); return This::STATUS_OKAY; } // R_ARM_MOVT_PREL: S + A - P static inline typename This::Status movt_prel(unsigned char *view, const Sized_relobj<32, big_endian>* object, const Symbol_value<32>* psymval, Arm_address address) { typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast(view); Valtype val = elfcpp::Swap<32, big_endian>::readval(wv); Valtype addend = This::extract_arm_movw_movt_addend(val); Valtype x = (psymval->value(object, addend) - address) >> 16; val = This::insert_val_arm_movw_movt(val, x); elfcpp::Swap<32, big_endian>::writeval(wv, val); return This::STATUS_OKAY; } // R_ARM_THM_MOVW_PREL_NC: (S + A) | T - P static inline typename This::Status thm_movw_prel_nc(unsigned char *view, const Sized_relobj<32, big_endian>* object, const Symbol_value<32>* psymval, Arm_address address, Arm_address thumb_bit) { typedef typename elfcpp::Swap<16, big_endian>::Valtype Valtype; typedef typename elfcpp::Swap<32, big_endian>::Valtype Reltype; Valtype* wv = reinterpret_cast(view); Reltype val = (elfcpp::Swap<16, big_endian>::readval(wv) << 16) | elfcpp::Swap<16, big_endian>::readval(wv + 1); Reltype addend = This::extract_thumb_movw_movt_addend(val); Reltype x = (psymval->value(object, addend) | thumb_bit) - address; val = This::insert_val_thumb_movw_movt(val, x); elfcpp::Swap<16, big_endian>::writeval(wv, val >> 16); elfcpp::Swap<16, big_endian>::writeval(wv + 1, val & 0xffff); return This::STATUS_OKAY; } // R_ARM_THM_MOVT_PREL: S + A - P static inline typename This::Status thm_movt_prel(unsigned char *view, const Sized_relobj<32, big_endian>* object, const Symbol_value<32>* psymval, Arm_address address) { typedef typename elfcpp::Swap<16, big_endian>::Valtype Valtype; typedef typename elfcpp::Swap<32, big_endian>::Valtype Reltype; Valtype* wv = reinterpret_cast(view); Reltype val = (elfcpp::Swap<16, big_endian>::readval(wv) << 16) | elfcpp::Swap<16, big_endian>::readval(wv + 1); Reltype addend = This::extract_thumb_movw_movt_addend(val); Reltype x = (psymval->value(object, addend) - address) >> 16; val = This::insert_val_thumb_movw_movt(val, x); elfcpp::Swap<16, big_endian>::writeval(wv, val >> 16); elfcpp::Swap<16, big_endian>::writeval(wv + 1, val & 0xffff); return This::STATUS_OKAY; } }; // Relocate ARM long branches. This handles relocation types // R_ARM_CALL, R_ARM_JUMP24, R_ARM_PLT32 and R_ARM_XPC25. // If IS_WEAK_UNDEFINED_WITH_PLT is true. The target symbol is weakly // undefined and we do not use PLT in this relocation. In such a case, // the branch is converted into an NOP. template typename Arm_relocate_functions::Status Arm_relocate_functions::arm_branch_common( unsigned int r_type, const Relocate_info<32, big_endian>* relinfo, unsigned char *view, const Sized_symbol<32>* gsym, const Arm_relobj* object, unsigned int r_sym, const Symbol_value<32>* psymval, Arm_address address, Arm_address thumb_bit, bool is_weakly_undefined_without_plt) { typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast(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; // Check that the instruction is valid. 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 if (r_type == elfcpp::R_ARM_XPC25) { // FIXME: AAELF document IH0044C does not say much about it other // than it being obsolete. if (!insn_is_any_branch) return This::STATUS_BAD_RELOC; } else gold_unreachable(); // A branch to an undefined weak symbol is turned into a jump to // the next instruction unless a PLT entry will be created. // Do the same for local undefined symbols. // The jump to the next instruction is optimized as a NOP depending // on the architecture. const Target_arm* arm_target = Target_arm::default_target(); if (is_weakly_undefined_without_plt) { Valtype cond = val & 0xf0000000U; if (arm_target->may_use_arm_nop()) val = cond | 0x0320f000; else val = cond | 0x01a00000; // Using pre-UAL nop: mov r0, r0. elfcpp::Swap<32, big_endian>::writeval(wv, val); return This::STATUS_OKAY; } Valtype addend = utils::sign_extend<26>(val << 2); Valtype branch_target = psymval->value(object, addend); int32_t branch_offset = branch_target - address; // We need a stub if the branch offset is too large or if we need // to switch mode. bool may_use_blx = arm_target->may_use_blx(); Reloc_stub* stub = NULL; if ((branch_offset > ARM_MAX_FWD_BRANCH_OFFSET) || (branch_offset < ARM_MAX_BWD_BRANCH_OFFSET) || ((thumb_bit != 0) && !(may_use_blx && r_type == elfcpp::R_ARM_CALL))) { Stub_type stub_type = Reloc_stub::stub_type_for_reloc(r_type, address, branch_target, (thumb_bit != 0)); if (stub_type != arm_stub_none) { Stub_table* stub_table = object->stub_table(relinfo->data_shndx); gold_assert(stub_table != NULL); Reloc_stub::Key stub_key(stub_type, gsym, object, r_sym, addend); stub = stub_table->find_reloc_stub(stub_key); gold_assert(stub != NULL); thumb_bit = stub->stub_template()->entry_in_thumb_mode() ? 1 : 0; branch_target = stub_table->address() + stub->offset() + addend; branch_offset = branch_target - address; gold_assert((branch_offset <= ARM_MAX_FWD_BRANCH_OFFSET) && (branch_offset >= ARM_MAX_BWD_BRANCH_OFFSET)); } } // At this point, if we still need to switch mode, the instruction // must either be a BLX or a BL that can be converted to a BLX. if (thumb_bit != 0) { // Turn BL to BLX. gold_assert(may_use_blx && r_type == elfcpp::R_ARM_CALL); val = (val & 0xffffff) | 0xfa000000 | ((branch_offset & 2) << 23); } val = utils::bit_select(val, (branch_offset >> 2), 0xffffffUL); elfcpp::Swap<32, big_endian>::writeval(wv, val); return (utils::has_overflow<26>(branch_offset) ? This::STATUS_OVERFLOW : This::STATUS_OKAY); } template Target_arm::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), stub_tables_(), stub_factory_(Stub_factory::get_instance()), target1_is_rel_(false), may_use_blx_(true), should_force_pic_veneer_(false), arm_input_section_map_() { // FIXME: This is not strictly compatible with ld, which allows both // --target1-abs and --target-rel to be given. if (parameters->options().user_set_target1_abs() && parameters->options().user_set_target1_rel()) { gold_error(_("Cannot use both --target1-abs and --target1-rel.")); } else if (parameters->options().user_set_target1_rel()) this->target1_is_rel_ = true; else if (parameters->options().user_set_target1_abs()) this->target1_is_rel_ = false; if (parameters->options().user_set_target2()) { if (strcmp(parameters->options().target2(), "rel") == 0) this->target2_reloc_ = elfcpp::R_ARM_REL32; else if (strcmp(parameters->options().target2(), "abs") == 0) this->target2_reloc_ = elfcpp::R_ARM_ABS32; else if (strcmp(parameters->options().target2(), "got-rel") == 0) this->target2_reloc_ = elfcpp::R_ARM_GOT_PREL; else gold_unreachable(); } else { // Default values for R_ARM_TARGET2: // // R_ARM_REL32 (arm*-*-elf, arm*-*-eabi) // R_ARM_ABS32 (arm*-*-symbianelf) // R_ARM_GOT_PREL (arm*-*-linux, arm*-*-*bsd) // This is the default value for EABI. this->target2_reloc_ = elfcpp::R_ARM_REL32; } } // Relocate THUMB long branches. This handles relocation types // R_ARM_THM_CALL, R_ARM_THM_JUMP24 and R_ARM_THM_XPC22. // If IS_WEAK_UNDEFINED_WITH_PLT is true. The target symbol is weakly // undefined and we do not use PLT in this relocation. In such a case, // the branch is converted into an NOP. template typename Arm_relocate_functions::Status Arm_relocate_functions::thumb_branch_common( unsigned int r_type, const Relocate_info<32, big_endian>* relinfo, unsigned char *view, const Sized_symbol<32>* gsym, const Arm_relobj* object, unsigned int r_sym, const Symbol_value<32>* psymval, Arm_address address, Arm_address thumb_bit, bool is_weakly_undefined_without_plt) { typedef typename elfcpp::Swap<16, big_endian>::Valtype Valtype; Valtype* wv = reinterpret_cast(view); uint32_t upper_insn = elfcpp::Swap<16, big_endian>::readval(wv); uint32_t lower_insn = elfcpp::Swap<16, big_endian>::readval(wv + 1); // FIXME: These tests are too loose and do not take THUMB/THUMB-2 difference // into account. bool is_bl_insn = (lower_insn & 0x1000U) == 0x1000U; bool is_blx_insn = (lower_insn & 0x1000U) == 0x0000U; // Check that the instruction is valid. if (r_type == elfcpp::R_ARM_THM_CALL) { if (!is_bl_insn && !is_blx_insn) return This::STATUS_BAD_RELOC; } else if (r_type == elfcpp::R_ARM_THM_JUMP24) { // This cannot be a BLX. if (!is_bl_insn) return This::STATUS_BAD_RELOC; } else if (r_type == elfcpp::R_ARM_THM_XPC22) { // Check for Thumb to Thumb call. if (!is_blx_insn) return This::STATUS_BAD_RELOC; if (thumb_bit != 0) { gold_warning(_("%s: Thumb BLX instruction targets " "thumb function '%s'."), object->name().c_str(), (gsym ? gsym->name() : "(local)")); // Convert BLX to BL. lower_insn |= 0x1000U; } } else gold_unreachable(); // A branch to an undefined weak symbol is turned into a jump to // the next instruction unless a PLT entry will be created. // The jump to the next instruction is optimized as a NOP.W for // Thumb-2 enabled architectures. const Target_arm* arm_target = Target_arm::default_target(); if (is_weakly_undefined_without_plt) { if (arm_target->may_use_thumb2_nop()) { elfcpp::Swap<16, big_endian>::writeval(wv, 0xf3af); elfcpp::Swap<16, big_endian>::writeval(wv + 1, 0x8000); } else { elfcpp::Swap<16, big_endian>::writeval(wv, 0xe000); elfcpp::Swap<16, big_endian>::writeval(wv + 1, 0xbf00); } return This::STATUS_OKAY; } // Fetch the addend. We use the Thumb-2 encoding (backwards compatible // with Thumb-1) involving the J1 and J2 bits. uint32_t s = (upper_insn & (1 << 10)) >> 10; uint32_t upper = upper_insn & 0x3ff; uint32_t lower = lower_insn & 0x7ff; uint32_t j1 = (lower_insn & (1 << 13)) >> 13; uint32_t j2 = (lower_insn & (1 << 11)) >> 11; uint32_t i1 = j1 ^ s ? 0 : 1; uint32_t i2 = j2 ^ s ? 0 : 1; int32_t addend = (i1 << 23) | (i2 << 22) | (upper << 12) | (lower << 1); // Sign extend. addend = (addend | ((s ? 0 : 1) << 24)) - (1 << 24); Arm_address branch_target = psymval->value(object, addend); int32_t branch_offset = branch_target - address; // We need a stub if the branch offset is too large or if we need // to switch mode. bool may_use_blx = arm_target->may_use_blx(); bool thumb2 = arm_target->using_thumb2(); if ((!thumb2 && (branch_offset > THM_MAX_FWD_BRANCH_OFFSET || (branch_offset < THM_MAX_BWD_BRANCH_OFFSET))) || (thumb2 && (branch_offset > THM2_MAX_FWD_BRANCH_OFFSET || (branch_offset < THM2_MAX_BWD_BRANCH_OFFSET))) || ((thumb_bit == 0) && (((r_type == elfcpp::R_ARM_THM_CALL) && !may_use_blx) || r_type == elfcpp::R_ARM_THM_JUMP24))) { Stub_type stub_type = Reloc_stub::stub_type_for_reloc(r_type, address, branch_target, (thumb_bit != 0)); if (stub_type != arm_stub_none) { Stub_table* stub_table = object->stub_table(relinfo->data_shndx); gold_assert(stub_table != NULL); Reloc_stub::Key stub_key(stub_type, gsym, object, r_sym, addend); Reloc_stub* stub = stub_table->find_reloc_stub(stub_key); gold_assert(stub != NULL); thumb_bit = stub->stub_template()->entry_in_thumb_mode() ? 1 : 0; branch_target = stub_table->address() + stub->offset() + addend; branch_offset = branch_target - address; } } // At this point, if we still need to switch mode, the instruction // must either be a BLX or a BL that can be converted to a BLX. if (thumb_bit == 0) { gold_assert(may_use_blx && (r_type == elfcpp::R_ARM_THM_CALL || r_type == elfcpp::R_ARM_THM_XPC22)); // Make sure this is a BLX. lower_insn &= ~0x1000U; } else { // Make sure this is a BL. lower_insn |= 0x1000U; } uint32_t reloc_sign = (branch_offset < 0) ? 1 : 0; uint32_t relocation = static_cast(branch_offset); if ((lower_insn & 0x5000U) == 0x4000U) // For a BLX instruction, make sure that the relocation is rounded up // to a word boundary. This follows the semantics of the instruction // which specifies that bit 1 of the target address will come from bit // 1 of the base address. relocation = (relocation + 2U) & ~3U; // Put BRANCH_OFFSET back into the insn. Assumes two's complement. // We use the Thumb-2 encoding, which is safe even if dealing with // a Thumb-1 instruction by virtue of our overflow check above. */ upper_insn = (upper_insn & ~0x7ffU) | ((relocation >> 12) & 0x3ffU) | (reloc_sign << 10); lower_insn = (lower_insn & ~0x2fffU) | (((!((relocation >> 23) & 1U)) ^ reloc_sign) << 13) | (((!((relocation >> 22) & 1U)) ^ reloc_sign) << 11) | ((relocation >> 1) & 0x7ffU); elfcpp::Swap<16, big_endian>::writeval(wv, upper_insn); elfcpp::Swap<16, big_endian>::writeval(wv + 1, lower_insn); return ((thumb2 ? utils::has_overflow<25>(relocation) : utils::has_overflow<23>(relocation)) ? This::STATUS_OVERFLOW : This::STATUS_OKAY); } // Get the GOT section, creating it if necessary. template Output_data_got<32, big_endian>* Target_arm::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_, false); 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_, false); 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 typename Target_arm::Reloc_section* Target_arm::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_, true); } return this->rel_dyn_; } // Insn_template methods. // Return byte size of an instruction template. size_t Insn_template::size() const { switch (this->type()) { case THUMB16_TYPE: return 2; case ARM_TYPE: case THUMB32_TYPE: case DATA_TYPE: return 4; default: gold_unreachable(); } } // Return alignment of an instruction template. unsigned Insn_template::alignment() const { switch (this->type()) { case THUMB16_TYPE: case THUMB32_TYPE: return 2; case ARM_TYPE: case DATA_TYPE: return 4; default: gold_unreachable(); } } // Stub_template methods. Stub_template::Stub_template( Stub_type type, const Insn_template* insns, size_t insn_count) : type_(type), insns_(insns), insn_count_(insn_count), alignment_(1), entry_in_thumb_mode_(false), relocs_() { off_t offset = 0; // Compute byte size and alignment of stub template. for (size_t i = 0; i < insn_count; i++) { unsigned insn_alignment = insns[i].alignment(); size_t insn_size = insns[i].size(); gold_assert((offset & (insn_alignment - 1)) == 0); this->alignment_ = std::max(this->alignment_, insn_alignment); switch (insns[i].type()) { case Insn_template::THUMB16_TYPE: if (i == 0) this->entry_in_thumb_mode_ = true; break; case Insn_template::THUMB32_TYPE: if (insns[i].r_type() != elfcpp::R_ARM_NONE) this->relocs_.push_back(Reloc(i, offset)); if (i == 0) this->entry_in_thumb_mode_ = true; break; case Insn_template::ARM_TYPE: // Handle cases where the target is encoded within the // instruction. if (insns[i].r_type() == elfcpp::R_ARM_JUMP24) this->relocs_.push_back(Reloc(i, offset)); break; case Insn_template::DATA_TYPE: // Entry point cannot be data. gold_assert(i != 0); this->relocs_.push_back(Reloc(i, offset)); break; default: gold_unreachable(); } offset += insn_size; } this->size_ = offset; } // Reloc_stub::Key methods. // Dump a Key as a string for debugging. std::string Reloc_stub::Key::name() const { if (this->r_sym_ == invalid_index) { // Global symbol key name // ::. const std::string sym_name = this->u_.symbol->name(); // We need to print two hex number and two colons. So just add 100 bytes // to the symbol name size. size_t len = sym_name.size() + 100; char* buffer = new char[len]; int c = snprintf(buffer, len, "%d:%s:%x", this->stub_type_, sym_name.c_str(), this->addend_); gold_assert(c > 0 && c < static_cast(len)); delete[] buffer; return std::string(buffer); } else { // local symbol key name // :::. const size_t len = 200; char buffer[len]; int c = snprintf(buffer, len, "%d:%p:%u:%x", this->stub_type_, this->u_.relobj, this->r_sym_, this->addend_); gold_assert(c > 0 && c < static_cast(len)); return std::string(buffer); } } // Reloc_stub methods. // Determine the type of stub needed, if any, for a relocation of R_TYPE at // LOCATION to DESTINATION. // This code is based on the arm_type_of_stub function in // bfd/elf32-arm.c. We have changed the interface a liitle to keep the Stub // class simple. Stub_type Reloc_stub::stub_type_for_reloc( unsigned int r_type, Arm_address location, Arm_address destination, bool target_is_thumb) { Stub_type stub_type = arm_stub_none; // This is a bit ugly but we want to avoid using a templated class for // big and little endianities. bool may_use_blx; bool should_force_pic_veneer; bool thumb2; bool thumb_only; if (parameters->target().is_big_endian()) { const Target_arm* big_endian_target = Target_arm::default_target(); may_use_blx = big_endian_target->may_use_blx(); should_force_pic_veneer = big_endian_target->should_force_pic_veneer(); thumb2 = big_endian_target->using_thumb2(); thumb_only = big_endian_target->using_thumb_only(); } else { const Target_arm* little_endian_target = Target_arm::default_target(); may_use_blx = little_endian_target->may_use_blx(); should_force_pic_veneer = little_endian_target->should_force_pic_veneer(); thumb2 = little_endian_target->using_thumb2(); thumb_only = little_endian_target->using_thumb_only(); } int64_t branch_offset = (int64_t)destination - location; if (r_type == elfcpp::R_ARM_THM_CALL || r_type == elfcpp::R_ARM_THM_JUMP24) { // Handle cases where: // - this call goes too far (different Thumb/Thumb2 max // distance) // - it's a Thumb->Arm call and blx is not available, or it's a // Thumb->Arm branch (not bl). A stub is needed in this case. if ((!thumb2 && (branch_offset > THM_MAX_FWD_BRANCH_OFFSET || (branch_offset < THM_MAX_BWD_BRANCH_OFFSET))) || (thumb2 && (branch_offset > THM2_MAX_FWD_BRANCH_OFFSET || (branch_offset < THM2_MAX_BWD_BRANCH_OFFSET))) || ((!target_is_thumb) && (((r_type == elfcpp::R_ARM_THM_CALL) && !may_use_blx) || (r_type == elfcpp::R_ARM_THM_JUMP24)))) { if (target_is_thumb) { // Thumb to thumb. if (!thumb_only) { stub_type = (parameters->options().shared() || should_force_pic_veneer) // PIC stubs. ? ((may_use_blx && (r_type == elfcpp::R_ARM_THM_CALL)) // V5T and above. Stub starts with ARM code, so // we must be able to switch mode before // reaching it, which is only possible for 'bl' // (ie R_ARM_THM_CALL relocation). ? arm_stub_long_branch_any_thumb_pic // On V4T, use Thumb code only. : arm_stub_long_branch_v4t_thumb_thumb_pic) // non-PIC stubs. : ((may_use_blx && (r_type == elfcpp::R_ARM_THM_CALL)) ? arm_stub_long_branch_any_any // V5T and above. : arm_stub_long_branch_v4t_thumb_thumb); // V4T. } else { stub_type = (parameters->options().shared() || should_force_pic_veneer) ? arm_stub_long_branch_thumb_only_pic // PIC stub. : arm_stub_long_branch_thumb_only; // non-PIC stub. } } else { // Thumb to arm. // FIXME: We should check that the input section is from an // object that has interwork enabled. stub_type = (parameters->options().shared() || should_force_pic_veneer) // PIC stubs. ? ((may_use_blx && (r_type == elfcpp::R_ARM_THM_CALL)) ? arm_stub_long_branch_any_arm_pic // V5T and above. : arm_stub_long_branch_v4t_thumb_arm_pic) // V4T. // non-PIC stubs. : ((may_use_blx && (r_type == elfcpp::R_ARM_THM_CALL)) ? arm_stub_long_branch_any_any // V5T and above. : arm_stub_long_branch_v4t_thumb_arm); // V4T. // Handle v4t short branches. if ((stub_type == arm_stub_long_branch_v4t_thumb_arm) && (branch_offset <= THM_MAX_FWD_BRANCH_OFFSET) && (branch_offset >= THM_MAX_BWD_BRANCH_OFFSET)) stub_type = arm_stub_short_branch_v4t_thumb_arm; } } } else if (r_type == elfcpp::R_ARM_CALL || r_type == elfcpp::R_ARM_JUMP24 || r_type == elfcpp::R_ARM_PLT32) { if (target_is_thumb) { // Arm to thumb. // FIXME: We should check that the input section is from an // object that has interwork enabled. // We have an extra 2-bytes reach because of // the mode change (bit 24 (H) of BLX encoding). if (branch_offset > (ARM_MAX_FWD_BRANCH_OFFSET + 2) || (branch_offset < ARM_MAX_BWD_BRANCH_OFFSET) || ((r_type == elfcpp::R_ARM_CALL) && !may_use_blx) || (r_type == elfcpp::R_ARM_JUMP24) || (r_type == elfcpp::R_ARM_PLT32)) { stub_type = (parameters->options().shared() || should_force_pic_veneer) // PIC stubs. ? (may_use_blx ? arm_stub_long_branch_any_thumb_pic// V5T and above. : arm_stub_long_branch_v4t_arm_thumb_pic) // V4T stub. // non-PIC stubs. : (may_use_blx ? arm_stub_long_branch_any_any // V5T and above. : arm_stub_long_branch_v4t_arm_thumb); // V4T. } } else { // Arm to arm. if (branch_offset > ARM_MAX_FWD_BRANCH_OFFSET || (branch_offset < ARM_MAX_BWD_BRANCH_OFFSET)) { stub_type = (parameters->options().shared() || should_force_pic_veneer) ? arm_stub_long_branch_any_arm_pic // PIC stubs. : arm_stub_long_branch_any_any; /// non-PIC. } } } return stub_type; } // Template to implement do_write for a specific target endianity. template void inline Reloc_stub::do_fixed_endian_write(unsigned char* view, section_size_type view_size) { const Stub_template* stub_template = this->stub_template(); const Insn_template* insns = stub_template->insns(); // FIXME: We do not handle BE8 encoding yet. unsigned char* pov = view; for (size_t i = 0; i < stub_template->insn_count(); i++) { switch (insns[i].type()) { case Insn_template::THUMB16_TYPE: // Non-zero reloc addends are only used in Cortex-A8 stubs. gold_assert(insns[i].reloc_addend() == 0); elfcpp::Swap<16, big_endian>::writeval(pov, insns[i].data() & 0xffff); break; case Insn_template::THUMB32_TYPE: { uint32_t hi = (insns[i].data() >> 16) & 0xffff; uint32_t lo = insns[i].data() & 0xffff; elfcpp::Swap<16, big_endian>::writeval(pov, hi); elfcpp::Swap<16, big_endian>::writeval(pov + 2, lo); } break; case Insn_template::ARM_TYPE: case Insn_template::DATA_TYPE: elfcpp::Swap<32, big_endian>::writeval(pov, insns[i].data()); break; default: gold_unreachable(); } pov += insns[i].size(); } gold_assert(static_cast(pov - view) == view_size); } // Write a reloc stub to VIEW with endianity specified by BIG_ENDIAN. void Reloc_stub::do_write(unsigned char* view, section_size_type view_size, bool big_endian) { if (big_endian) this->do_fixed_endian_write(view, view_size); else this->do_fixed_endian_write(view, view_size); } // Stub_factory methods. Stub_factory::Stub_factory() { // The instruction template sequences are declared as static // objects and initialized first time the constructor runs. // Arm/Thumb -> Arm/Thumb long branch stub. On V5T and above, use blx // to reach the stub if necessary. static const Insn_template elf32_arm_stub_long_branch_any_any[] = { Insn_template::arm_insn(0xe51ff004), // ldr pc, [pc, #-4] Insn_template::data_word(0, elfcpp::R_ARM_ABS32, 0), // dcd R_ARM_ABS32(X) }; // V4T Arm -> Thumb long branch stub. Used on V4T where blx is not // available. static const Insn_template elf32_arm_stub_long_branch_v4t_arm_thumb[] = { Insn_template::arm_insn(0xe59fc000), // ldr ip, [pc, #0] Insn_template::arm_insn(0xe12fff1c), // bx ip Insn_template::data_word(0, elfcpp::R_ARM_ABS32, 0), // dcd R_ARM_ABS32(X) }; // Thumb -> Thumb long branch stub. Used on M-profile architectures. static const Insn_template elf32_arm_stub_long_branch_thumb_only[] = { Insn_template::thumb16_insn(0xb401), // push {r0} Insn_template::thumb16_insn(0x4802), // ldr r0, [pc, #8] Insn_template::thumb16_insn(0x4684), // mov ip, r0 Insn_template::thumb16_insn(0xbc01), // pop {r0} Insn_template::thumb16_insn(0x4760), // bx ip Insn_template::thumb16_insn(0xbf00), // nop Insn_template::data_word(0, elfcpp::R_ARM_ABS32, 0), // dcd R_ARM_ABS32(X) }; // V4T Thumb -> Thumb long branch stub. Using the stack is not // allowed. static const Insn_template elf32_arm_stub_long_branch_v4t_thumb_thumb[] = { Insn_template::thumb16_insn(0x4778), // bx pc Insn_template::thumb16_insn(0x46c0), // nop Insn_template::arm_insn(0xe59fc000), // ldr ip, [pc, #0] Insn_template::arm_insn(0xe12fff1c), // bx ip Insn_template::data_word(0, elfcpp::R_ARM_ABS32, 0), // dcd R_ARM_ABS32(X) }; // V4T Thumb -> ARM long branch stub. Used on V4T where blx is not // available. static const Insn_template elf32_arm_stub_long_branch_v4t_thumb_arm[] = { Insn_template::thumb16_insn(0x4778), // bx pc Insn_template::thumb16_insn(0x46c0), // nop Insn_template::arm_insn(0xe51ff004), // ldr pc, [pc, #-4] Insn_template::data_word(0, elfcpp::R_ARM_ABS32, 0), // dcd R_ARM_ABS32(X) }; // V4T Thumb -> ARM short branch stub. Shorter variant of the above // one, when the destination is close enough. static const Insn_template elf32_arm_stub_short_branch_v4t_thumb_arm[] = { Insn_template::thumb16_insn(0x4778), // bx pc Insn_template::thumb16_insn(0x46c0), // nop Insn_template::arm_rel_insn(0xea000000, -8), // b (X-8) }; // ARM/Thumb -> ARM long branch stub, PIC. On V5T and above, use // blx to reach the stub if necessary. static const Insn_template elf32_arm_stub_long_branch_any_arm_pic[] = { Insn_template::arm_insn(0xe59fc000), // ldr r12, [pc] Insn_template::arm_insn(0xe08ff00c), // add pc, pc, ip Insn_template::data_word(0, elfcpp::R_ARM_REL32, -4), // dcd R_ARM_REL32(X-4) }; // ARM/Thumb -> Thumb long branch stub, PIC. On V5T and above, use // blx to reach the stub if necessary. We can not add into pc; // it is not guaranteed to mode switch (different in ARMv6 and // ARMv7). static const Insn_template elf32_arm_stub_long_branch_any_thumb_pic[] = { Insn_template::arm_insn(0xe59fc004), // ldr r12, [pc, #4] Insn_template::arm_insn(0xe08fc00c), // add ip, pc, ip Insn_template::arm_insn(0xe12fff1c), // bx ip Insn_template::data_word(0, elfcpp::R_ARM_REL32, 0), // dcd R_ARM_REL32(X) }; // V4T ARM -> ARM long branch stub, PIC. static const Insn_template elf32_arm_stub_long_branch_v4t_arm_thumb_pic[] = { Insn_template::arm_insn(0xe59fc004), // ldr ip, [pc, #4] Insn_template::arm_insn(0xe08fc00c), // add ip, pc, ip Insn_template::arm_insn(0xe12fff1c), // bx ip Insn_template::data_word(0, elfcpp::R_ARM_REL32, 0), // dcd R_ARM_REL32(X) }; // V4T Thumb -> ARM long branch stub, PIC. static const Insn_template elf32_arm_stub_long_branch_v4t_thumb_arm_pic[] = { Insn_template::thumb16_insn(0x4778), // bx pc Insn_template::thumb16_insn(0x46c0), // nop Insn_template::arm_insn(0xe59fc000), // ldr ip, [pc, #0] Insn_template::arm_insn(0xe08cf00f), // add pc, ip, pc Insn_template::data_word(0, elfcpp::R_ARM_REL32, -4), // dcd R_ARM_REL32(X) }; // Thumb -> Thumb long branch stub, PIC. Used on M-profile // architectures. static const Insn_template elf32_arm_stub_long_branch_thumb_only_pic[] = { Insn_template::thumb16_insn(0xb401), // push {r0} Insn_template::thumb16_insn(0x4802), // ldr r0, [pc, #8] Insn_template::thumb16_insn(0x46fc), // mov ip, pc Insn_template::thumb16_insn(0x4484), // add ip, r0 Insn_template::thumb16_insn(0xbc01), // pop {r0} Insn_template::thumb16_insn(0x4760), // bx ip Insn_template::data_word(0, elfcpp::R_ARM_REL32, 4), // dcd R_ARM_REL32(X) }; // V4T Thumb -> Thumb long branch stub, PIC. Using the stack is not // allowed. static const Insn_template elf32_arm_stub_long_branch_v4t_thumb_thumb_pic[] = { Insn_template::thumb16_insn(0x4778), // bx pc Insn_template::thumb16_insn(0x46c0), // nop Insn_template::arm_insn(0xe59fc004), // ldr ip, [pc, #4] Insn_template::arm_insn(0xe08fc00c), // add ip, pc, ip Insn_template::arm_insn(0xe12fff1c), // bx ip Insn_template::data_word(0, elfcpp::R_ARM_REL32, 0), // dcd R_ARM_REL32(X) }; // Cortex-A8 erratum-workaround stubs. // Stub used for conditional branches (which may be beyond +/-1MB away, // so we can't use a conditional branch to reach this stub). // original code: // // b X // after: // static const Insn_template elf32_arm_stub_a8_veneer_b_cond[] = { Insn_template::thumb16_bcond_insn(0xd001), // b.n true Insn_template::thumb32_b_insn(0xf000b800, -4), // b.w after Insn_template::thumb32_b_insn(0xf000b800, -4) // true: // b.w X }; // Stub used for b.w and bl.w instructions. static const Insn_template elf32_arm_stub_a8_veneer_b[] = { Insn_template::thumb32_b_insn(0xf000b800, -4) // b.w dest }; static const Insn_template elf32_arm_stub_a8_veneer_bl[] = { Insn_template::thumb32_b_insn(0xf000b800, -4) // b.w dest }; // Stub used for Thumb-2 blx.w instructions. We modified the original blx.w // instruction (which switches to ARM mode) to point to this stub. Jump to // the real destination using an ARM-mode branch. const Insn_template elf32_arm_stub_a8_veneer_blx[] = { Insn_template::arm_rel_insn(0xea000000, -8) // b dest }; // Fill in the stub template look-up table. Stub templates are constructed // per instance of Stub_factory for fast look-up without locking // in a thread-enabled environment. this->stub_templates_[arm_stub_none] = new Stub_template(arm_stub_none, NULL, 0); #define DEF_STUB(x) \ do \ { \ size_t array_size \ = sizeof(elf32_arm_stub_##x) / sizeof(elf32_arm_stub_##x[0]); \ Stub_type type = arm_stub_##x; \ this->stub_templates_[type] = \ new Stub_template(type, elf32_arm_stub_##x, array_size); \ } \ while (0); DEF_STUBS #undef DEF_STUB } // Stub_table methods. // Add a STUB with using KEY. Caller is reponsible for avoid adding // if already a STUB with the same key has been added. template void Stub_table::add_reloc_stub( Reloc_stub* stub, const Reloc_stub::Key& key) { const Stub_template* stub_template = stub->stub_template(); gold_assert(stub_template->type() == key.stub_type()); this->reloc_stubs_[key] = stub; if (this->addralign_ < stub_template->alignment()) this->addralign_ = stub_template->alignment(); this->has_been_changed_ = true; } template void Stub_table::relocate_stubs( const Relocate_info<32, big_endian>* relinfo, Target_arm* arm_target, Output_section* output_section, unsigned char* view, Arm_address address, section_size_type view_size) { // If we are passed a view bigger than the stub table's. we need to // adjust the view. gold_assert(address == this->address() && (view_size == static_cast(this->data_size()))); for (typename Reloc_stub_map::const_iterator p = this->reloc_stubs_.begin(); p != this->reloc_stubs_.end(); ++p) { Reloc_stub* stub = p->second; const Stub_template* stub_template = stub->stub_template(); if (stub_template->reloc_count() != 0) { // Adjust view to cover the stub only. section_size_type offset = stub->offset(); section_size_type stub_size = stub_template->size(); gold_assert(offset + stub_size <= view_size); arm_target->relocate_stub(stub, relinfo, output_section, view + offset, address + offset, stub_size); } } } // Reset address and file offset. template void Stub_table::do_reset_address_and_file_offset() { off_t off = 0; uint64_t max_addralign = 1; for (typename Reloc_stub_map::const_iterator p = this->reloc_stubs_.begin(); p != this->reloc_stubs_.end(); ++p) { Reloc_stub* stub = p->second; const Stub_template* stub_template = stub->stub_template(); uint64_t stub_addralign = stub_template->alignment(); max_addralign = std::max(max_addralign, stub_addralign); off = align_address(off, stub_addralign); stub->set_offset(off); stub->reset_destination_address(); off += stub_template->size(); } this->addralign_ = max_addralign; this->set_current_data_size_for_child(off); } // Write out the stubs to file. template void Stub_table::do_write(Output_file* of) { 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); for (typename Reloc_stub_map::const_iterator p = this->reloc_stubs_.begin(); p != this->reloc_stubs_.end(); ++p) { Reloc_stub* stub = p->second; Arm_address address = this->address() + stub->offset(); gold_assert(address == align_address(address, stub->stub_template()->alignment())); stub->write(oview + stub->offset(), stub->stub_template()->size(), big_endian); } of->write_output_view(this->offset(), oview_size, oview); } // Arm_input_section methods. // Initialize an Arm_input_section. template void Arm_input_section::init() { Relobj* relobj = this->relobj(); unsigned int shndx = this->shndx(); // Cache these to speed up size and alignment queries. It is too slow // to call section_addraglin and section_size every time. this->original_addralign_ = relobj->section_addralign(shndx); this->original_size_ = relobj->section_size(shndx); // We want to make this look like the original input section after // output sections are finalized. Output_section* os = relobj->output_section(shndx); off_t offset = relobj->output_section_offset(shndx); gold_assert(os != NULL && !relobj->is_output_section_offset_invalid(shndx)); this->set_address(os->address() + offset); this->set_file_offset(os->offset() + offset); this->set_current_data_size(this->original_size_); this->finalize_data_size(); } template void Arm_input_section::do_write(Output_file* of) { // We have to write out the original section content. section_size_type section_size; const unsigned char* section_contents = this->relobj()->section_contents(this->shndx(), §ion_size, false); of->write(this->offset(), section_contents, section_size); // If this owns a stub table and it is not empty, write it. if (this->is_stub_table_owner() && !this->stub_table_->empty()) this->stub_table_->write(of); } // Finalize data size. template void Arm_input_section::set_final_data_size() { // If this owns a stub table, finalize its data size as well. if (this->is_stub_table_owner()) { uint64_t address = this->address(); // The stub table comes after the original section contents. address += this->original_size_; address = align_address(address, this->stub_table_->addralign()); off_t offset = this->offset() + (address - this->address()); this->stub_table_->set_address_and_file_offset(address, offset); address += this->stub_table_->data_size(); gold_assert(address == this->address() + this->current_data_size()); } this->set_data_size(this->current_data_size()); } // Reset address and file offset. template void Arm_input_section::do_reset_address_and_file_offset() { // Size of the original input section contents. off_t off = convert_types(this->original_size_); // If this is a stub table owner, account for the stub table size. if (this->is_stub_table_owner()) { Stub_table* stub_table = this->stub_table_; // Reset the stub table's address and file offset. The // current data size for child will be updated after that. stub_table_->reset_address_and_file_offset(); off = align_address(off, stub_table_->addralign()); off += stub_table->current_data_size(); } this->set_current_data_size(off); } // Arm_output_section methods. // Create a stub group for input sections from BEGIN to END. OWNER // points to the input section to be the owner a new stub table. template void Arm_output_section::create_stub_group( Input_section_list::const_iterator begin, Input_section_list::const_iterator end, Input_section_list::const_iterator owner, Target_arm* target, std::vector* new_relaxed_sections) { // Currently we convert ordinary input sections into relaxed sections only // at this point but we may want to support creating relaxed input section // very early. So we check here to see if owner is already a relaxed // section. Arm_input_section* arm_input_section; if (owner->is_relaxed_input_section()) { arm_input_section = Arm_input_section::as_arm_input_section( owner->relaxed_input_section()); } else { gold_assert(owner->is_input_section()); // Create a new relaxed input section. arm_input_section = target->new_arm_input_section(owner->relobj(), owner->shndx()); new_relaxed_sections->push_back(arm_input_section); } // Create a stub table. Stub_table* stub_table = target->new_stub_table(arm_input_section); arm_input_section->set_stub_table(stub_table); Input_section_list::const_iterator p = begin; Input_section_list::const_iterator prev_p; // Look for input sections or relaxed input sections in [begin ... end]. do { if (p->is_input_section() || p->is_relaxed_input_section()) { // The stub table information for input sections live // in their objects. Arm_relobj* arm_relobj = Arm_relobj::as_arm_relobj(p->relobj()); arm_relobj->set_stub_table(p->shndx(), stub_table); } prev_p = p++; } while (prev_p != end); } // Group input sections for stub generation. GROUP_SIZE is roughly the limit // of stub groups. We grow a stub group by adding input section until the // size is just below GROUP_SIZE. The last input section will be converted // into a stub table. If STUB_ALWAYS_AFTER_BRANCH is false, we also add // input section after the stub table, effectively double the group size. // // This is similar to the group_sections() function in elf32-arm.c but is // implemented differently. template void Arm_output_section::group_sections( section_size_type group_size, bool stubs_always_after_branch, Target_arm* target) { // We only care about sections containing code. if ((this->flags() & elfcpp::SHF_EXECINSTR) == 0) return; // States for grouping. typedef enum { // No group is being built. NO_GROUP, // A group is being built but the stub table is not found yet. // We keep group a stub group until the size is just under GROUP_SIZE. // The last input section in the group will be used as the stub table. FINDING_STUB_SECTION, // A group is being built and we have already found a stub table. // We enter this state to grow a stub group by adding input section // after the stub table. This effectively doubles the group size. HAS_STUB_SECTION } State; // Any newly created relaxed sections are stored here. std::vector new_relaxed_sections; State state = NO_GROUP; section_size_type off = 0; section_size_type group_begin_offset = 0; section_size_type group_end_offset = 0; section_size_type stub_table_end_offset = 0; Input_section_list::const_iterator group_begin = this->input_sections().end(); Input_section_list::const_iterator stub_table = this->input_sections().end(); Input_section_list::const_iterator group_end = this->input_sections().end(); for (Input_section_list::const_iterator p = this->input_sections().begin(); p != this->input_sections().end(); ++p) { section_size_type section_begin_offset = align_address(off, p->addralign()); section_size_type section_end_offset = section_begin_offset + p->data_size(); // Check to see if we should group the previously seens sections. switch (state) { case NO_GROUP: break; case FINDING_STUB_SECTION: // Adding this section makes the group larger than GROUP_SIZE. if (section_end_offset - group_begin_offset >= group_size) { if (stubs_always_after_branch) { gold_assert(group_end != this->input_sections().end()); this->create_stub_group(group_begin, group_end, group_end, target, &new_relaxed_sections); state = NO_GROUP; } else { // But wait, there's more! Input sections up to // stub_group_size bytes after the stub table can be // handled by it too. state = HAS_STUB_SECTION; stub_table = group_end; stub_table_end_offset = group_end_offset; } } break; case HAS_STUB_SECTION: // Adding this section makes the post stub-section group larger // than GROUP_SIZE. if (section_end_offset - stub_table_end_offset >= group_size) { gold_assert(group_end != this->input_sections().end()); this->create_stub_group(group_begin, group_end, stub_table, target, &new_relaxed_sections); state = NO_GROUP; } break; default: gold_unreachable(); } // If we see an input section and currently there is no group, start // a new one. Skip any empty sections. if ((p->is_input_section() || p->is_relaxed_input_section()) && (p->relobj()->section_size(p->shndx()) != 0)) { if (state == NO_GROUP) { state = FINDING_STUB_SECTION; group_begin = p; group_begin_offset = section_begin_offset; } // Keep track of the last input section seen. group_end = p; group_end_offset = section_end_offset; } off = section_end_offset; } // Create a stub group for any ungrouped sections. if (state == FINDING_STUB_SECTION || state == HAS_STUB_SECTION) { gold_assert(group_end != this->input_sections().end()); this->create_stub_group(group_begin, group_end, (state == FINDING_STUB_SECTION ? group_end : stub_table), target, &new_relaxed_sections); } // Convert input section into relaxed input section in a batch. if (!new_relaxed_sections.empty()) this->convert_input_sections_to_relaxed_sections(new_relaxed_sections); // Update the section offsets for (size_t i = 0; i < new_relaxed_sections.size(); ++i) { Arm_relobj* arm_relobj = Arm_relobj::as_arm_relobj( new_relaxed_sections[i]->relobj()); unsigned int shndx = new_relaxed_sections[i]->shndx(); // Tell Arm_relobj that this input section is converted. arm_relobj->convert_input_section_to_relaxed_section(shndx); } } // Arm_relobj methods. // Scan relocations for stub generation. template void Arm_relobj::scan_sections_for_stubs( Target_arm* arm_target, const Symbol_table* symtab, const Layout* layout) { unsigned int shnum = this->shnum(); const unsigned int shdr_size = elfcpp::Elf_sizes<32>::shdr_size; // Read the section headers. const unsigned char* pshdrs = this->get_view(this->elf_file()->shoff(), shnum * shdr_size, true, true); // To speed up processing, we set up hash tables for fast lookup of // input offsets to output addresses. this->initialize_input_to_output_maps(); const Relobj::Output_sections& out_sections(this->output_sections()); Relocate_info<32, big_endian> relinfo; relinfo.symtab = symtab; relinfo.layout = layout; relinfo.object = this; const unsigned char* p = pshdrs + shdr_size; for (unsigned int i = 1; i < shnum; ++i, p += shdr_size) { typename elfcpp::Shdr<32, big_endian> shdr(p); unsigned int sh_type = shdr.get_sh_type(); if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA) continue; off_t sh_size = shdr.get_sh_size(); if (sh_size == 0) continue; unsigned int index = this->adjust_shndx(shdr.get_sh_info()); if (index >= this->shnum()) { // Ignore reloc section with bad info. This error will be // reported in the final link. continue; } Output_section* os = out_sections[index]; if (os == NULL) { // This relocation section is against a section which we // discarded. continue; } Arm_address output_offset = this->get_output_section_offset(index); if (this->adjust_shndx(shdr.get_sh_link()) != this->symtab_shndx()) { // Ignore reloc section with unexpected symbol table. The // error will be reported in the final link. continue; } const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(), sh_size, true, false); unsigned int reloc_size; if (sh_type == elfcpp::SHT_REL) reloc_size = elfcpp::Elf_sizes<32>::rel_size; else reloc_size = elfcpp::Elf_sizes<32>::rela_size; if (reloc_size != shdr.get_sh_entsize()) { // Ignore reloc section with unexpected entsize. The error // will be reported in the final link. continue; } size_t reloc_count = sh_size / reloc_size; if (static_cast(reloc_count * reloc_size) != sh_size) { // Ignore reloc section with uneven size. The error will be // reported in the final link. continue; } gold_assert(output_offset != invalid_address || this->relocs_must_follow_section_writes()); // Get the section contents. This does work for the case in which // we modify the contents of an input section. We need to pass the // output view under such circumstances. section_size_type input_view_size = 0; const unsigned char* input_view = this->section_contents(index, &input_view_size, false); relinfo.reloc_shndx = i; relinfo.data_shndx = index; arm_target->scan_section_for_stubs(&relinfo, sh_type, prelocs, reloc_count, os, output_offset == invalid_address, input_view, os->address(), input_view_size); } // After we've done the relocations, we release the hash tables, // since we no longer need them. this->free_input_to_output_maps(); } // Count the local symbols. The ARM backend needs to know if a symbol // is a THUMB function or not. For global symbols, it is easy because // the Symbol object keeps the ELF symbol type. For local symbol it is // harder because we cannot access this information. So we override the // do_count_local_symbol in parent and scan local symbols to mark // THUMB functions. This is not the most efficient way but I do not want to // slow down other ports by calling a per symbol targer hook inside // Sized_relobj::do_count_local_symbols. template void Arm_relobj::do_count_local_symbols( Stringpool_template* pool, Stringpool_template* dynpool) { // We need to fix-up the values of any local symbols whose type are // STT_ARM_TFUNC. // Ask parent to count the local symbols. Sized_relobj<32, big_endian>::do_count_local_symbols(pool, dynpool); const unsigned int loccount = this->local_symbol_count(); if (loccount == 0) return; // Intialize the thumb function bit-vector. std::vector empty_vector(loccount, false); this->local_symbol_is_thumb_function_.swap(empty_vector); // Read the symbol table section header. const unsigned int symtab_shndx = this->symtab_shndx(); elfcpp::Shdr<32, big_endian> symtabshdr(this, this->elf_file()->section_header(symtab_shndx)); gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB); // Read the local symbols. const int sym_size =elfcpp::Elf_sizes<32>::sym_size; gold_assert(loccount == symtabshdr.get_sh_info()); off_t locsize = loccount * sym_size; const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(), locsize, true, true); // Loop over the local symbols and mark any local symbols pointing // to THUMB functions. // Skip the first dummy symbol. psyms += sym_size; typename Sized_relobj<32, big_endian>::Local_values* plocal_values = this->local_values(); for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size) { elfcpp::Sym<32, big_endian> sym(psyms); elfcpp::STT st_type = sym.get_st_type(); Symbol_value<32>& lv((*plocal_values)[i]); Arm_address input_value = lv.input_value(); if (st_type == elfcpp::STT_ARM_TFUNC || (st_type == elfcpp::STT_FUNC && ((input_value & 1) != 0))) { // This is a THUMB function. Mark this and canonicalize the // symbol value by setting LSB. this->local_symbol_is_thumb_function_[i] = true; if ((input_value & 1) == 0) lv.set_input_value(input_value | 1); } } } // Relocate sections. template void Arm_relobj::do_relocate_sections( const Symbol_table* symtab, const Layout* layout, const unsigned char* pshdrs, typename Sized_relobj<32, big_endian>::Views* pviews) { // Call parent to relocate sections. Sized_relobj<32, big_endian>::do_relocate_sections(symtab, layout, pshdrs, pviews); // We do not generate stubs if doing a relocatable link. if (parameters->options().relocatable()) return; // Relocate stub tables. unsigned int shnum = this->shnum(); Target_arm* arm_target = Target_arm::default_target(); Relocate_info<32, big_endian> relinfo; relinfo.symtab = symtab; relinfo.layout = layout; relinfo.object = this; for (unsigned int i = 1; i < shnum; ++i) { Arm_input_section* arm_input_section = arm_target->find_arm_input_section(this, i); if (arm_input_section == NULL || !arm_input_section->is_stub_table_owner() || arm_input_section->stub_table()->empty()) continue; // We cannot discard a section if it owns a stub table. Output_section* os = this->output_section(i); gold_assert(os != NULL); relinfo.reloc_shndx = elfcpp::SHN_UNDEF; relinfo.reloc_shdr = NULL; relinfo.data_shndx = i; relinfo.data_shdr = pshdrs + i * elfcpp::Elf_sizes<32>::shdr_size; gold_assert((*pviews)[i].view != NULL); // We are passed the output section view. Adjust it to cover the // stub table only. Stub_table* stub_table = arm_input_section->stub_table(); gold_assert((stub_table->address() >= (*pviews)[i].address) && ((stub_table->address() + stub_table->data_size()) <= (*pviews)[i].address + (*pviews)[i].view_size)); off_t offset = stub_table->address() - (*pviews)[i].address; unsigned char* view = (*pviews)[i].view + offset; Arm_address address = stub_table->address(); section_size_type view_size = stub_table->data_size(); stub_table->relocate_stubs(&relinfo, arm_target, os, view, address, view_size); } } // Read the symbol information. template void Arm_relobj::do_read_symbols(Read_symbols_data* sd) { // Call parent class to read symbol information. Sized_relobj<32, big_endian>::do_read_symbols(sd); // Read processor-specific flags in ELF file header. const unsigned char* pehdr = this->get_view(elfcpp::file_header_offset, elfcpp::Elf_sizes<32>::ehdr_size, true, false); elfcpp::Ehdr<32, big_endian> ehdr(pehdr); this->processor_specific_flags_ = ehdr.get_e_flags(); } // Arm_dynobj methods. // Read the symbol information. template void Arm_dynobj::do_read_symbols(Read_symbols_data* sd) { // Call parent class to read symbol information. Sized_dynobj<32, big_endian>::do_read_symbols(sd); // Read processor-specific flags in ELF file header. const unsigned char* pehdr = this->get_view(elfcpp::file_header_offset, elfcpp::Elf_sizes<32>::ehdr_size, true, false); elfcpp::Ehdr<32, big_endian> ehdr(pehdr); this->processor_specific_flags_ = ehdr.get_e_flags(); } // Stub_addend_reader methods. // Read the addend of a REL relocation of type R_TYPE at VIEW. template elfcpp::Elf_types<32>::Elf_Swxword Stub_addend_reader::operator()( unsigned int r_type, const unsigned char* view, const typename Reloc_types::Reloc&) const { switch (r_type) { case elfcpp::R_ARM_CALL: case elfcpp::R_ARM_JUMP24: case elfcpp::R_ARM_PLT32: { typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype; const Valtype* wv = reinterpret_cast(view); Valtype val = elfcpp::Swap<32, big_endian>::readval(wv); return utils::sign_extend<26>(val << 2); } case elfcpp::R_ARM_THM_CALL: case elfcpp::R_ARM_THM_JUMP24: case elfcpp::R_ARM_THM_XPC22: { // Fetch the addend. We use the Thumb-2 encoding (backwards // compatible with Thumb-1) involving the J1 and J2 bits. typedef typename elfcpp::Swap<16, big_endian>::Valtype Valtype; const Valtype* wv = reinterpret_cast(view); Valtype upper_insn = elfcpp::Swap<16, big_endian>::readval(wv); Valtype lower_insn = elfcpp::Swap<16, big_endian>::readval(wv + 1); uint32_t s = (upper_insn & (1 << 10)) >> 10; uint32_t upper = upper_insn & 0x3ff; uint32_t lower = lower_insn & 0x7ff; uint32_t j1 = (lower_insn & (1 << 13)) >> 13; uint32_t j2 = (lower_insn & (1 << 11)) >> 11; uint32_t i1 = j1 ^ s ? 0 : 1; uint32_t i2 = j2 ^ s ? 0 : 1; return utils::sign_extend<25>((s << 24) | (i1 << 23) | (i2 << 22) | (upper << 12) | (lower << 1)); } case elfcpp::R_ARM_THM_JUMP19: { typedef typename elfcpp::Swap<16, big_endian>::Valtype Valtype; const Valtype* wv = reinterpret_cast(view); Valtype upper_insn = elfcpp::Swap<16, big_endian>::readval(wv); Valtype lower_insn = elfcpp::Swap<16, big_endian>::readval(wv + 1); // Reconstruct the top three bits and squish the two 11 bit pieces // together. uint32_t S = (upper_insn & 0x0400) >> 10; uint32_t J1 = (lower_insn & 0x2000) >> 13; uint32_t J2 = (lower_insn & 0x0800) >> 11; uint32_t upper = (S << 8) | (J2 << 7) | (J1 << 6) | (upper_insn & 0x003f); uint32_t lower = (lower_insn & 0x07ff); return utils::sign_extend<23>((upper << 12) | (lower << 1)); } default: gold_unreachable(); } } // A class to handle the PLT data. template class Output_data_plt_arm : public Output_section_data { public: typedef Output_data_reloc 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 Output_data_plt_arm::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_, true); } template void Output_data_plt_arm::do_adjust_output_section(Output_section* os) { os->set_entsize(0); } // Add an entry to the PLT. template void Output_data_plt_arm::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 const uint32_t Output_data_plt_arm::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 const uint32_t Output_data_plt_arm::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 void Output_data_plt_arm::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; Arm_address plt_address = this->address(); Arm_address 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(pov - oview) == oview_size); gold_assert(static_cast(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 void Target_arm::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(layout, this->got_plt_); layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR), this->plt_, false); } this->plt_->add_entry(gsym); } // Report an unsupported relocation against a local symbol. template void Target_arm::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 void Target_arm::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_ABS32_NOI: 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 inline void Target_arm::Scan::local(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 = target->get_real_reloc_type(r_type); switch (r_type) { case elfcpp::R_ARM_NONE: break; case elfcpp::R_ARM_ABS32: case elfcpp::R_ARM_ABS32_NOI: // 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: case elfcpp::R_ARM_THM_ABS5: case elfcpp::R_ARM_ABS8: case elfcpp::R_ARM_ABS12: case elfcpp::R_ARM_ABS16: case elfcpp::R_ARM_BASE_ABS: case elfcpp::R_ARM_MOVW_ABS_NC: case elfcpp::R_ARM_MOVT_ABS: case elfcpp::R_ARM_THM_MOVW_ABS_NC: case elfcpp::R_ARM_THM_MOVT_ABS: case elfcpp::R_ARM_MOVW_PREL_NC: case elfcpp::R_ARM_MOVT_PREL: case elfcpp::R_ARM_THM_MOVW_PREL_NC: case elfcpp::R_ARM_THM_MOVT_PREL: 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: case elfcpp::R_ARM_GOT_PREL: { // 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 void Target_arm::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 inline void Target_arm::Scan::global(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 = target->get_real_reloc_type(r_type); switch (r_type) { case elfcpp::R_ARM_NONE: break; case elfcpp::R_ARM_ABS32: case elfcpp::R_ARM_ABS32_NOI: { // 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_MOVW_ABS_NC: case elfcpp::R_ARM_MOVT_ABS: case elfcpp::R_ARM_THM_MOVW_ABS_NC: case elfcpp::R_ARM_THM_MOVT_ABS: case elfcpp::R_ARM_MOVW_PREL_NC: case elfcpp::R_ARM_MOVT_PREL: case elfcpp::R_ARM_THM_MOVW_PREL_NC: case elfcpp::R_ARM_THM_MOVT_PREL: break; case elfcpp::R_ARM_THM_ABS5: case elfcpp::R_ARM_ABS8: case elfcpp::R_ARM_ABS12: case elfcpp::R_ARM_ABS16: case elfcpp::R_ARM_BASE_ABS: { // No dynamic relocs of this kinds. // Report the error in case of PIC. 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)) check_non_pic(object, r_type); } 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::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: case elfcpp::R_ARM_GOT_PREL: { // 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 void Target_arm::gc_process_relocs(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 Arm; typedef typename Target_arm::Scan Scan; gold::gc_process_relocs<32, big_endian, Arm, elfcpp::SHT_REL, Scan>( 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 void Target_arm::scan_relocs(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::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>( symtab, layout, this, object, data_shndx, prelocs, reloc_count, output_section, needs_special_offset_handling, local_symbol_count, plocal_symbols); } // Finalize the sections. template void Target_arm::do_finalize_sections( Layout* layout, const Input_objects* input_objects) { // Merge processor-specific flags. for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); p != input_objects->relobj_end(); ++p) { Arm_relobj* arm_relobj = Arm_relobj::as_arm_relobj(*p); this->merge_processor_specific_flags( arm_relobj->name(), arm_relobj->processor_specific_flags()); } for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin(); p != input_objects->dynobj_end(); ++p) { Arm_dynobj* arm_dynobj = Arm_dynobj::as_arm_dynobj(*p); this->merge_processor_specific_flags( arm_dynobj->name(), arm_dynobj->processor_specific_flags()); } // Fill in some more dynamic tags. Output_data_dynamic* const odyn = layout->dynamic_data(); if (odyn != NULL) { if (this->got_plt_ != NULL && this->got_plt_->output_section() != NULL) odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_); if (this->plt_ != NULL && this->plt_->output_section() != 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 && this->rel_dyn_->output_section() != 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, false); } } } // 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 inline bool Target_arm::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 inline bool Target_arm::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, Arm_address address, section_size_type /* view_size */ ) { typedef Arm_relocate_functions Arm_relocate_functions; r_type = target->get_real_reloc_type(r_type); const Arm_relobj* object = Arm_relobj::as_arm_relobj(relinfo->object); // If the final branch target of a relocation is THUMB instruction, this // is 1. Otherwise it is 0. Arm_address thumb_bit = 0; Symbol_value<32> symval; bool is_weakly_undefined_without_plt = false; if (relnum != Target_arm::fake_relnum_for_stubs) { if (gsym != NULL) { // This is a global symbol. Determine if we use PLT and if the // final target is THUMB. if (gsym->use_plt_offset(reloc_is_non_pic(r_type))) { // This uses a PLT, change the symbol value. symval.set_output_value(target->plt_section()->address() + gsym->plt_offset()); psymval = &symval; } else if (gsym->is_weak_undefined()) { // This is a weakly undefined symbol and we do not use PLT // for this relocation. A branch targeting this symbol will // be converted into an NOP. is_weakly_undefined_without_plt = true; } else { // Set thumb bit if symbol: // -Has type STT_ARM_TFUNC or // -Has type STT_FUNC, is defined and with LSB in value set. thumb_bit = (((gsym->type() == elfcpp::STT_ARM_TFUNC) || (gsym->type() == elfcpp::STT_FUNC && !gsym->is_undefined() && ((psymval->value(object, 0) & 1) != 0))) ? 1 : 0); } } else { // This is a local symbol. Determine if the final target is THUMB. // We saved this information when all the local symbols were read. elfcpp::Elf_types<32>::Elf_WXword r_info = rel.get_r_info(); unsigned int r_sym = elfcpp::elf_r_sym<32>(r_info); thumb_bit = object->local_symbol_is_thumb_function(r_sym) ? 1 : 0; } } else { // This is a fake relocation synthesized for a stub. It does not have // a real symbol. We just look at the LSB of the symbol value to // determine if the target is THUMB or not. thumb_bit = ((psymval->value(object, 0) & 1) != 0); } // Strip LSB if this points to a THUMB target. if (thumb_bit != 0 && Target_arm::reloc_uses_thumb_bit(r_type) && ((psymval->value(object, 0) & 1) != 0)) { Arm_address stripped_value = psymval->value(object, 0) & ~static_cast(1); symval.set_output_value(stripped_value); psymval = &symval; } // 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: case elfcpp::R_ARM_GOT_PREL: 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; } // To look up relocation stubs, we need to pass the symbol table index of // a local symbol. unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); 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_ABS8: if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false, output_section)) reloc_status = Arm_relocate_functions::abs8(view, object, psymval); break; case elfcpp::R_ARM_ABS12: if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false, output_section)) reloc_status = Arm_relocate_functions::abs12(view, object, psymval); break; case elfcpp::R_ARM_ABS16: if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false, output_section)) reloc_status = Arm_relocate_functions::abs16(view, object, psymval); 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, thumb_bit); break; case elfcpp::R_ARM_ABS32_NOI: if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true, output_section)) // No thumb bit for this relocation: (S + A) reloc_status = Arm_relocate_functions::abs32(view, object, psymval, false); break; case elfcpp::R_ARM_MOVW_ABS_NC: if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true, output_section)) reloc_status = Arm_relocate_functions::movw_abs_nc(view, object, psymval, thumb_bit); else gold_error(_("relocation R_ARM_MOVW_ABS_NC cannot be used when making" "a shared object; recompile with -fPIC")); break; case elfcpp::R_ARM_MOVT_ABS: if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true, output_section)) reloc_status = Arm_relocate_functions::movt_abs(view, object, psymval); else gold_error(_("relocation R_ARM_MOVT_ABS cannot be used when making" "a shared object; recompile with -fPIC")); break; case elfcpp::R_ARM_THM_MOVW_ABS_NC: if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true, output_section)) reloc_status = Arm_relocate_functions::thm_movw_abs_nc(view, object, psymval, thumb_bit); else gold_error(_("relocation R_ARM_THM_MOVW_ABS_NC cannot be used when" "making a shared object; recompile with -fPIC")); break; case elfcpp::R_ARM_THM_MOVT_ABS: if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true, output_section)) reloc_status = Arm_relocate_functions::thm_movt_abs(view, object, psymval); else gold_error(_("relocation R_ARM_THM_MOVT_ABS cannot be used when" "making a shared object; recompile with -fPIC")); break; case elfcpp::R_ARM_MOVW_PREL_NC: reloc_status = Arm_relocate_functions::movw_prel_nc(view, object, psymval, address, thumb_bit); break; case elfcpp::R_ARM_MOVT_PREL: reloc_status = Arm_relocate_functions::movt_prel(view, object, psymval, address); break; case elfcpp::R_ARM_THM_MOVW_PREL_NC: reloc_status = Arm_relocate_functions::thm_movw_prel_nc(view, object, psymval, address, thumb_bit); break; case elfcpp::R_ARM_THM_MOVT_PREL: reloc_status = Arm_relocate_functions::thm_movt_prel(view, object, psymval, address); break; case elfcpp::R_ARM_REL32: reloc_status = Arm_relocate_functions::rel32(view, object, psymval, address, thumb_bit); break; case elfcpp::R_ARM_THM_ABS5: if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false, output_section)) reloc_status = Arm_relocate_functions::thm_abs5(view, object, psymval); break; case elfcpp::R_ARM_THM_CALL: reloc_status = Arm_relocate_functions::thm_call(relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); break; case elfcpp::R_ARM_XPC25: reloc_status = Arm_relocate_functions::xpc25(relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); break; case elfcpp::R_ARM_THM_XPC22: reloc_status = Arm_relocate_functions::thm_xpc22(relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); break; case elfcpp::R_ARM_GOTOFF32: { Arm_address got_origin; got_origin = target->got_plt_section()->address(); reloc_status = Arm_relocate_functions::rel32(view, object, psymval, got_origin, 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_BASE_ABS: { if (!should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true, output_section)) break; uint32_t origin; // Get the addressing origin of the output segment defining // the symbol gsym (AAELF 4.6.1.2 Relocation types). if (gsym == NULL) // R_ARM_BASE_ABS with the NULL symbol will give the // absolute address of the GOT origin (GOT_ORG) (see ARM IHI // 0044C (AAELF): 4.6.1.8 Proxy generating relocations). origin = target->got_plt_section()->address(); else 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_ABS")); return true; } reloc_status = Arm_relocate_functions::base_abs(view, origin); } 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_GOT_PREL: gold_assert(have_got_offset); // Get the address origin for GOT PLT, which is allocated right // after the GOT section, to calculate an absolute address of // the symbol GOT entry (got_origin + got_offset). Arm_address got_origin; got_origin = target->got_plt_section()->address(); reloc_status = Arm_relocate_functions::got_prel(view, got_origin + got_offset, address); 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(relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); break; case elfcpp::R_ARM_CALL: reloc_status = Arm_relocate_functions::call(relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); break; case elfcpp::R_ARM_JUMP24: reloc_status = Arm_relocate_functions::jump24(relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); break; case elfcpp::R_ARM_THM_JUMP24: reloc_status = Arm_relocate_functions::thm_jump24(relinfo, view, gsym, object, r_sym, psymval, address, thumb_bit, is_weakly_undefined_without_plt); break; case elfcpp::R_ARM_PREL31: reloc_status = Arm_relocate_functions::prel31(view, object, psymval, address, 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 void Target_arm::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, Arm_address address, section_size_type view_size, const Reloc_symbol_changes* reloc_symbol_changes) { typedef typename Target_arm::Relocate Arm_relocate; gold_assert(sh_type == elfcpp::SHT_REL); Arm_input_section* arm_input_section = this->find_arm_input_section(relinfo->object, relinfo->data_shndx); // This is an ARM input section and the view covers the whole output // section. if (arm_input_section != NULL) { gold_assert(needs_special_offset_handling); Arm_address section_address = arm_input_section->address(); section_size_type section_size = arm_input_section->data_size(); gold_assert((arm_input_section->address() >= address) && ((arm_input_section->address() + arm_input_section->data_size()) <= (address + view_size))); off_t offset = section_address - address; view += offset; address += offset; view_size = section_size; } 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, reloc_symbol_changes); } // Return the size of a relocation while scanning during a relocatable // link. template unsigned int Target_arm::Relocatable_size_for_reloc::get_size_for_reloc( unsigned int r_type, Relobj* object) { const Target_arm* arm_target = Target_arm::default_target(); r_type = arm_target->get_real_reloc_type(r_type); switch (r_type) { case elfcpp::R_ARM_NONE: return 0; case elfcpp::R_ARM_ABS8: return 1; case elfcpp::R_ARM_ABS16: case elfcpp::R_ARM_THM_ABS5: return 2; case elfcpp::R_ARM_ABS32: case elfcpp::R_ARM_ABS32_NOI: case elfcpp::R_ARM_ABS12: case elfcpp::R_ARM_BASE_ABS: 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_GOT_PREL: case elfcpp::R_ARM_PLT32: case elfcpp::R_ARM_CALL: case elfcpp::R_ARM_JUMP24: case elfcpp::R_ARM_PREL31: case elfcpp::R_ARM_MOVW_ABS_NC: case elfcpp::R_ARM_MOVT_ABS: case elfcpp::R_ARM_THM_MOVW_ABS_NC: case elfcpp::R_ARM_THM_MOVT_ABS: case elfcpp::R_ARM_MOVW_PREL_NC: case elfcpp::R_ARM_MOVT_PREL: case elfcpp::R_ARM_THM_MOVW_PREL_NC: case elfcpp::R_ARM_THM_MOVT_PREL: 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 void Target_arm::scan_relocatable_relocs( 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 Scan_relocatable_relocs; gold::scan_relocatable_relocs<32, big_endian, elfcpp::SHT_REL, Scan_relocatable_relocs>( 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 void Target_arm::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, Arm_address 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 uint64_t Target_arm::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 unsigned int Target_arm::get_real_reloc_type (unsigned int r_type) const { switch (r_type) { case elfcpp::R_ARM_TARGET1: return this->target1_is_rel_? elfcpp::R_ARM_REL32 : elfcpp::R_ARM_ABS32; case elfcpp::R_ARM_TARGET2: return this->target2_reloc_; default: return r_type; } } // Whether if two EABI versions V1 and V2 are compatible. template bool Target_arm::are_eabi_versions_compatible( elfcpp::Elf_Word v1, elfcpp::Elf_Word v2) { // v4 and v5 are the same spec before and after it was released, // so allow mixing them. if ((v1 == elfcpp::EF_ARM_EABI_VER4 && v2 == elfcpp::EF_ARM_EABI_VER5) || (v1 == elfcpp::EF_ARM_EABI_VER5 && v2 == elfcpp::EF_ARM_EABI_VER4)) return true; return v1 == v2; } // Combine FLAGS from an input object called NAME and the processor-specific // flags in the ELF header of the output. Much of this is adapted from the // processor-specific flags merging code in elf32_arm_merge_private_bfd_data // in bfd/elf32-arm.c. template void Target_arm::merge_processor_specific_flags( const std::string& name, elfcpp::Elf_Word flags) { if (this->are_processor_specific_flags_set()) { elfcpp::Elf_Word out_flags = this->processor_specific_flags(); // Nothing to merge if flags equal to those in output. if (flags == out_flags) return; // Complain about various flag mismatches. elfcpp::Elf_Word version1 = elfcpp::arm_eabi_version(flags); elfcpp::Elf_Word version2 = elfcpp::arm_eabi_version(out_flags); if (!this->are_eabi_versions_compatible(version1, version2)) gold_error(_("Source object %s has EABI version %d but output has " "EABI version %d."), name.c_str(), (flags & elfcpp::EF_ARM_EABIMASK) >> 24, (out_flags & elfcpp::EF_ARM_EABIMASK) >> 24); } else { // If the input is the default architecture and had the default // flags then do not bother setting the flags for the output // architecture, instead allow future merges to do this. If no // future merges ever set these flags then they will retain their // uninitialised values, which surprise surprise, correspond // to the default values. if (flags == 0) return; // This is the first time, just copy the flags. // We only copy the EABI version for now. this->set_processor_specific_flags(flags & elfcpp::EF_ARM_EABIMASK); } } // Adjust ELF file header. template void Target_arm::do_adjust_elf_header( unsigned char* view, int len) const { gold_assert(len == elfcpp::Elf_sizes<32>::ehdr_size); elfcpp::Ehdr<32, big_endian> ehdr(view); unsigned char e_ident[elfcpp::EI_NIDENT]; memcpy(e_ident, ehdr.get_e_ident(), elfcpp::EI_NIDENT); if (elfcpp::arm_eabi_version(this->processor_specific_flags()) == elfcpp::EF_ARM_EABI_UNKNOWN) e_ident[elfcpp::EI_OSABI] = elfcpp::ELFOSABI_ARM; else e_ident[elfcpp::EI_OSABI] = 0; e_ident[elfcpp::EI_ABIVERSION] = 0; // FIXME: Do EF_ARM_BE8 adjustment. elfcpp::Ehdr_write<32, big_endian> oehdr(view); oehdr.put_e_ident(e_ident); } // do_make_elf_object to override the same function in the base class. // We need to use a target-specific sub-class of Sized_relobj<32, big_endian> // to store ARM specific information. Hence we need to have our own // ELF object creation. template Object* Target_arm::do_make_elf_object( const std::string& name, Input_file* input_file, off_t offset, const elfcpp::Ehdr<32, big_endian>& ehdr) { int et = ehdr.get_e_type(); if (et == elfcpp::ET_REL) { Arm_relobj* obj = new Arm_relobj(name, input_file, offset, ehdr); obj->setup(); return obj; } else if (et == elfcpp::ET_DYN) { Sized_dynobj<32, big_endian>* obj = new Arm_dynobj(name, input_file, offset, ehdr); obj->setup(); return obj; } else { gold_error(_("%s: unsupported ELF file type %d"), name.c_str(), et); return NULL; } } // Return whether a relocation type used the LSB to distinguish THUMB // addresses. template bool Target_arm::reloc_uses_thumb_bit(unsigned int r_type) { switch (r_type) { case elfcpp::R_ARM_PC24: case elfcpp::R_ARM_ABS32: case elfcpp::R_ARM_REL32: case elfcpp::R_ARM_SBREL32: case elfcpp::R_ARM_THM_CALL: case elfcpp::R_ARM_GLOB_DAT: case elfcpp::R_ARM_JUMP_SLOT: case elfcpp::R_ARM_GOTOFF32: case elfcpp::R_ARM_PLT32: case elfcpp::R_ARM_CALL: case elfcpp::R_ARM_JUMP24: case elfcpp::R_ARM_THM_JUMP24: case elfcpp::R_ARM_SBREL31: case elfcpp::R_ARM_PREL31: case elfcpp::R_ARM_MOVW_ABS_NC: case elfcpp::R_ARM_MOVW_PREL_NC: case elfcpp::R_ARM_THM_MOVW_ABS_NC: case elfcpp::R_ARM_THM_MOVW_PREL_NC: case elfcpp::R_ARM_THM_JUMP19: case elfcpp::R_ARM_THM_ALU_PREL_11_0: case elfcpp::R_ARM_ALU_PC_G0_NC: case elfcpp::R_ARM_ALU_PC_G0: case elfcpp::R_ARM_ALU_PC_G1_NC: case elfcpp::R_ARM_ALU_PC_G1: case elfcpp::R_ARM_ALU_PC_G2: case elfcpp::R_ARM_ALU_SB_G0_NC: case elfcpp::R_ARM_ALU_SB_G0: case elfcpp::R_ARM_ALU_SB_G1_NC: case elfcpp::R_ARM_ALU_SB_G1: case elfcpp::R_ARM_ALU_SB_G2: case elfcpp::R_ARM_MOVW_BREL_NC: case elfcpp::R_ARM_MOVW_BREL: case elfcpp::R_ARM_THM_MOVW_BREL_NC: case elfcpp::R_ARM_THM_MOVW_BREL: return true; default: return false; } } // Stub-generation methods for Target_arm. // Make a new Arm_input_section object. template Arm_input_section* Target_arm::new_arm_input_section( Relobj* relobj, unsigned int shndx) { Input_section_specifier iss(relobj, shndx); Arm_input_section* arm_input_section = new Arm_input_section(relobj, shndx); arm_input_section->init(); // Register new Arm_input_section in map for look-up. std::pair ins = this->arm_input_section_map_.insert(std::make_pair(iss, arm_input_section)); // Make sure that it we have not created another Arm_input_section // for this input section already. gold_assert(ins.second); return arm_input_section; } // Find the Arm_input_section object corresponding to the SHNDX-th input // section of RELOBJ. template Arm_input_section* Target_arm::find_arm_input_section( Relobj* relobj, unsigned int shndx) const { Input_section_specifier iss(relobj, shndx); typename Arm_input_section_map::const_iterator p = this->arm_input_section_map_.find(iss); return (p != this->arm_input_section_map_.end()) ? p->second : NULL; } // Make a new stub table. template Stub_table* Target_arm::new_stub_table(Arm_input_section* owner) { Stub_table* stub_table = new Stub_table(owner); this->stub_tables_.push_back(stub_table); stub_table->set_address(owner->address() + owner->data_size()); stub_table->set_file_offset(owner->offset() + owner->data_size()); stub_table->finalize_data_size(); return stub_table; } // Scan a relocation for stub generation. template void Target_arm::scan_reloc_for_stub( const Relocate_info<32, big_endian>* relinfo, unsigned int r_type, const Sized_symbol<32>* gsym, unsigned int r_sym, const Symbol_value<32>* psymval, elfcpp::Elf_types<32>::Elf_Swxword addend, Arm_address address) { typedef typename Target_arm::Relocate Relocate; const Arm_relobj* arm_relobj = Arm_relobj::as_arm_relobj(relinfo->object); bool target_is_thumb; Symbol_value<32> symval; if (gsym != NULL) { // This is a global symbol. Determine if we use PLT and if the // final target is THUMB. if (gsym->use_plt_offset(Relocate::reloc_is_non_pic(r_type))) { // This uses a PLT, change the symbol value. symval.set_output_value(this->plt_section()->address() + gsym->plt_offset()); psymval = &symval; target_is_thumb = false; } else if (gsym->is_undefined()) // There is no need to generate a stub symbol is undefined. return; else { target_is_thumb = ((gsym->type() == elfcpp::STT_ARM_TFUNC) || (gsym->type() == elfcpp::STT_FUNC && !gsym->is_undefined() && ((psymval->value(arm_relobj, 0) & 1) != 0))); } } else { // This is a local symbol. Determine if the final target is THUMB. target_is_thumb = arm_relobj->local_symbol_is_thumb_function(r_sym); } // Strip LSB if this points to a THUMB target. if (target_is_thumb && Target_arm::reloc_uses_thumb_bit(r_type) && ((psymval->value(arm_relobj, 0) & 1) != 0)) { Arm_address stripped_value = psymval->value(arm_relobj, 0) & ~static_cast(1); symval.set_output_value(stripped_value); psymval = &symval; } // Get the symbol value. Symbol_value<32>::Value value = psymval->value(arm_relobj, 0); // Owing to pipelining, the PC relative branches below actually skip // two instructions when the branch offset is 0. Arm_address destination; switch (r_type) { case elfcpp::R_ARM_CALL: case elfcpp::R_ARM_JUMP24: case elfcpp::R_ARM_PLT32: // ARM branches. destination = value + addend + 8; break; case elfcpp::R_ARM_THM_CALL: case elfcpp::R_ARM_THM_XPC22: case elfcpp::R_ARM_THM_JUMP24: case elfcpp::R_ARM_THM_JUMP19: // THUMB branches. destination = value + addend + 4; break; default: gold_unreachable(); } Stub_type stub_type = Reloc_stub::stub_type_for_reloc(r_type, address, destination, target_is_thumb); // This reloc does not need a stub. if (stub_type == arm_stub_none) return; // Try looking up an existing stub from a stub table. Stub_table* stub_table = arm_relobj->stub_table(relinfo->data_shndx); gold_assert(stub_table != NULL); // Locate stub by destination. Reloc_stub::Key stub_key(stub_type, gsym, arm_relobj, r_sym, addend); // Create a stub if there is not one already Reloc_stub* stub = stub_table->find_reloc_stub(stub_key); if (stub == NULL) { // create a new stub and add it to stub table. stub = this->stub_factory().make_reloc_stub(stub_type); stub_table->add_reloc_stub(stub, stub_key); } // Record the destination address. stub->set_destination_address(destination | (target_is_thumb ? 1 : 0)); } // This function scans a relocation sections for stub generation. // The template parameter Relocate must be a class type which provides // a single function, relocate(), which implements the machine // specific part of a relocation. // BIG_ENDIAN is the endianness of the data. SH_TYPE is the section type: // SHT_REL or SHT_RELA. // PRELOCS points to the relocation data. RELOC_COUNT is the number // of relocs. OUTPUT_SECTION is the output section. // NEEDS_SPECIAL_OFFSET_HANDLING is true if input offsets need to be // mapped to output offsets. // VIEW is the section data, VIEW_ADDRESS is its memory address, and // VIEW_SIZE is the size. These refer to the input section, unless // NEEDS_SPECIAL_OFFSET_HANDLING is true, in which case they refer to // the output section. template template void inline Target_arm::scan_reloc_section_for_stubs( const Relocate_info<32, big_endian>* relinfo, const unsigned char* prelocs, size_t reloc_count, Output_section* output_section, bool needs_special_offset_handling, const unsigned char* view, elfcpp::Elf_types<32>::Elf_Addr view_address, section_size_type) { typedef typename Reloc_types::Reloc Reltype; const int reloc_size = Reloc_types::reloc_size; Arm_relobj* arm_object = Arm_relobj::as_arm_relobj(relinfo->object); unsigned int local_count = arm_object->local_symbol_count(); Comdat_behavior comdat_behavior = CB_UNDETERMINED; for (size_t i = 0; i < reloc_count; ++i, prelocs += reloc_size) { Reltype reloc(prelocs); typename elfcpp::Elf_types<32>::Elf_WXword r_info = reloc.get_r_info(); unsigned int r_sym = elfcpp::elf_r_sym<32>(r_info); unsigned int r_type = elfcpp::elf_r_type<32>(r_info); r_type = this->get_real_reloc_type(r_type); // Only a few relocation types need stubs. if ((r_type != elfcpp::R_ARM_CALL) && (r_type != elfcpp::R_ARM_JUMP24) && (r_type != elfcpp::R_ARM_PLT32) && (r_type != elfcpp::R_ARM_THM_CALL) && (r_type != elfcpp::R_ARM_THM_XPC22) && (r_type != elfcpp::R_ARM_THM_JUMP24) && (r_type != elfcpp::R_ARM_THM_JUMP19)) continue; section_offset_type offset = convert_to_section_size_type(reloc.get_r_offset()); if (needs_special_offset_handling) { offset = output_section->output_offset(relinfo->object, relinfo->data_shndx, offset); if (offset == -1) continue; } // Get the addend. Stub_addend_reader stub_addend_reader; elfcpp::Elf_types<32>::Elf_Swxword addend = stub_addend_reader(r_type, view + offset, reloc); const Sized_symbol<32>* sym; Symbol_value<32> symval; const Symbol_value<32> *psymval; if (r_sym < local_count) { sym = NULL; psymval = arm_object->local_symbol(r_sym); // If the local symbol belongs to a section we are discarding, // and that section is a debug section, try to find the // corresponding kept section and map this symbol to its // counterpart in the kept section. The symbol must not // correspond to a section we are folding. bool is_ordinary; unsigned int shndx = psymval->input_shndx(&is_ordinary); if (is_ordinary && shndx != elfcpp::SHN_UNDEF && !arm_object->is_section_included(shndx) && !(relinfo->symtab->is_section_folded(arm_object, shndx))) { if (comdat_behavior == CB_UNDETERMINED) { std::string name = arm_object->section_name(relinfo->data_shndx); comdat_behavior = get_comdat_behavior(name.c_str()); } if (comdat_behavior == CB_PRETEND) { bool found; typename elfcpp::Elf_types<32>::Elf_Addr value = arm_object->map_to_kept_section(shndx, &found); if (found) symval.set_output_value(value + psymval->input_value()); else symval.set_output_value(0); } else { symval.set_output_value(0); } symval.set_no_output_symtab_entry(); psymval = &symval; } } else { const Symbol* gsym = arm_object->global_symbol(r_sym); gold_assert(gsym != NULL); if (gsym->is_forwarder()) gsym = relinfo->symtab->resolve_forwards(gsym); sym = static_cast*>(gsym); if (sym->has_symtab_index()) symval.set_output_symtab_index(sym->symtab_index()); else symval.set_no_output_symtab_entry(); // We need to compute the would-be final value of this global // symbol. const Symbol_table* symtab = relinfo->symtab; const Sized_symbol<32>* sized_symbol = symtab->get_sized_symbol<32>(gsym); Symbol_table::Compute_final_value_status status; Arm_address value = symtab->compute_final_value<32>(sized_symbol, &status); // Skip this if the symbol has not output section. if (status == Symbol_table::CFVS_NO_OUTPUT_SECTION) continue; symval.set_output_value(value); psymval = &symval; } // If symbol is a section symbol, we don't know the actual type of // destination. Give up. if (psymval->is_section_symbol()) continue; this->scan_reloc_for_stub(relinfo, r_type, sym, r_sym, psymval, addend, view_address + offset); } } // Scan an input section for stub generation. template void Target_arm::scan_section_for_stubs( 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, const unsigned char* view, Arm_address view_address, section_size_type view_size) { if (sh_type == elfcpp::SHT_REL) this->scan_reloc_section_for_stubs( relinfo, prelocs, reloc_count, output_section, needs_special_offset_handling, view, view_address, view_size); else if (sh_type == elfcpp::SHT_RELA) // We do not support RELA type relocations yet. This is provided for // completeness. this->scan_reloc_section_for_stubs( relinfo, prelocs, reloc_count, output_section, needs_special_offset_handling, view, view_address, view_size); else gold_unreachable(); } // Group input sections for stub generation. // // We goup input sections in an output sections so that the total size, // including any padding space due to alignment is smaller than GROUP_SIZE // unless the only input section in group is bigger than GROUP_SIZE already. // Then an ARM stub table is created to follow the last input section // in group. For each group an ARM stub table is created an is placed // after the last group. If STUB_ALWATS_AFTER_BRANCH is false, we further // extend the group after the stub table. template void Target_arm::group_sections( Layout* layout, section_size_type group_size, bool stubs_always_after_branch) { // Group input sections and insert stub table Layout::Section_list section_list; layout->get_allocated_sections(§ion_list); for (Layout::Section_list::const_iterator p = section_list.begin(); p != section_list.end(); ++p) { Arm_output_section* output_section = Arm_output_section::as_arm_output_section(*p); output_section->group_sections(group_size, stubs_always_after_branch, this); } } // Relaxation hook. This is where we do stub generation. template bool Target_arm::do_relax( int pass, const Input_objects* input_objects, Symbol_table* symtab, Layout* layout) { // No need to generate stubs if this is a relocatable link. gold_assert(!parameters->options().relocatable()); // If this is the first pass, we need to group input sections into // stub groups. if (pass == 1) { // Determine the stub group size. The group size is the absolute // value of the parameter --stub-group-size. If --stub-group-size // is passed a negative value, we restict stubs to be always after // the stubbed branches. int32_t stub_group_size_param = parameters->options().stub_group_size(); bool stubs_always_after_branch = stub_group_size_param < 0; section_size_type stub_group_size = abs(stub_group_size_param); if (stub_group_size == 1) { // Default value. // Thumb branch range is +-4MB has to be used as the default // maximum size (a given section can contain both ARM and Thumb // code, so the worst case has to be taken into account). // // This value is 24K less than that, which allows for 2025 // 12-byte stubs. If we exceed that, then we will fail to link. // The user will have to relink with an explicit group size // option. stub_group_size = 4170000; } group_sections(layout, stub_group_size, stubs_always_after_branch); } // clear changed flags for all stub_tables typedef typename Stub_table_list::iterator Stub_table_iterator; for (Stub_table_iterator sp = this->stub_tables_.begin(); sp != this->stub_tables_.end(); ++sp) (*sp)->set_has_been_changed(false); // scan relocs for stubs for (Input_objects::Relobj_iterator op = input_objects->relobj_begin(); op != input_objects->relobj_end(); ++op) { Arm_relobj* arm_relobj = Arm_relobj::as_arm_relobj(*op); arm_relobj->scan_sections_for_stubs(this, symtab, layout); } bool any_stub_table_changed = false; for (Stub_table_iterator sp = this->stub_tables_.begin(); (sp != this->stub_tables_.end()) && !any_stub_table_changed; ++sp) { if ((*sp)->has_been_changed()) any_stub_table_changed = true; } return any_stub_table_changed; } // Relocate a stub. template void Target_arm::relocate_stub( Reloc_stub* stub, const Relocate_info<32, big_endian>* relinfo, Output_section* output_section, unsigned char* view, Arm_address address, section_size_type view_size) { Relocate relocate; const Stub_template* stub_template = stub->stub_template(); for (size_t i = 0; i < stub_template->reloc_count(); i++) { size_t reloc_insn_index = stub_template->reloc_insn_index(i); const Insn_template* insn = &stub_template->insns()[reloc_insn_index]; unsigned int r_type = insn->r_type(); section_size_type reloc_offset = stub_template->reloc_offset(i); section_size_type reloc_size = insn->size(); gold_assert(reloc_offset + reloc_size <= view_size); // This is the address of the stub destination. Arm_address target = stub->reloc_target(i); Symbol_value<32> symval; symval.set_output_value(target); // Synthesize a fake reloc just in case. We don't have a symbol so // we use 0. unsigned char reloc_buffer[elfcpp::Elf_sizes<32>::rel_size]; memset(reloc_buffer, 0, sizeof(reloc_buffer)); elfcpp::Rel_write<32, big_endian> reloc_write(reloc_buffer); reloc_write.put_r_offset(reloc_offset); reloc_write.put_r_info(elfcpp::elf_r_info<32>(0, r_type)); elfcpp::Rel<32, big_endian> rel(reloc_buffer); relocate.relocate(relinfo, this, output_section, this->fake_relnum_for_stubs, rel, r_type, NULL, &symval, view + reloc_offset, address + reloc_offset, reloc_size); } } // The selector for arm object files. template 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(); } }; Target_selector_arm target_selector_arm; Target_selector_arm target_selector_armbe; } // End anonymous namespace.