| // i386.cc -- i386 target support for gold. |
| |
| // Copyright 2006, 2007, 2008 Free Software Foundation, Inc. |
| // Written by Ian Lance Taylor <iant@google.com>. |
| |
| // This file is part of gold. |
| |
| // This program is free software; you can redistribute it and/or modify |
| // it under the terms of the GNU General Public License as published by |
| // the Free Software Foundation; either version 3 of the License, or |
| // (at your option) any later version. |
| |
| // This program is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // You should have received a copy of the GNU General Public License |
| // along with this program; if not, write to the Free Software |
| // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| // MA 02110-1301, USA. |
| |
| #include "gold.h" |
| |
| #include <cstring> |
| |
| #include "elfcpp.h" |
| #include "parameters.h" |
| #include "reloc.h" |
| #include "i386.h" |
| #include "object.h" |
| #include "symtab.h" |
| #include "layout.h" |
| #include "output.h" |
| #include "target.h" |
| #include "target-reloc.h" |
| #include "target-select.h" |
| #include "tls.h" |
| |
| namespace |
| { |
| |
| using namespace gold; |
| |
| class Output_data_plt_i386; |
| |
| // The i386 target class. |
| // TLS info comes from |
| // http://people.redhat.com/drepper/tls.pdf |
| // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt |
| |
| class Target_i386 : public Sized_target<32, false> |
| { |
| public: |
| typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section; |
| |
| Target_i386() |
| : Sized_target<32, false>(&i386_info), |
| got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL), |
| copy_relocs_(NULL), dynbss_(NULL), got_mod_index_offset_(-1U) |
| { } |
| |
| // Scan the relocations to look for symbol adjustments. |
| void |
| scan_relocs(const General_options& options, |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<32, false>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols); |
| |
| // Finalize the sections. |
| void |
| do_finalize_sections(Layout*); |
| |
| // Return the value to use for a dynamic which requires special |
| // treatment. |
| uint64_t |
| do_dynsym_value(const Symbol*) const; |
| |
| // Relocate a section. |
| void |
| relocate_section(const Relocate_info<32, false>*, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr view_address, |
| section_size_type view_size); |
| |
| // Scan the relocs during a relocatable link. |
| void |
| scan_relocatable_relocs(const General_options& options, |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<32, false>* 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, false>*, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| off_t offset_in_output_section, |
| const Relocatable_relocs*, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr view_address, |
| section_size_type view_size, |
| unsigned char* reloc_view, |
| section_size_type reloc_view_size); |
| |
| // Return a string used to fill a code section with nops. |
| std::string |
| do_code_fill(section_size_type length) const; |
| |
| // 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(); |
| } |
| |
| private: |
| // The class which scans relocations. |
| struct Scan |
| { |
| inline void |
| local(const General_options& options, Symbol_table* symtab, |
| Layout* layout, Target_i386* target, |
| Sized_relobj<32, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, false>& reloc, unsigned int r_type, |
| const elfcpp::Sym<32, false>& lsym); |
| |
| inline void |
| global(const General_options& options, Symbol_table* symtab, |
| Layout* layout, Target_i386* target, |
| Sized_relobj<32, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, false>& reloc, unsigned int r_type, |
| Symbol* gsym); |
| |
| static void |
| unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type); |
| |
| static void |
| unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type, |
| Symbol*); |
| }; |
| |
| // The class which implements relocation. |
| class Relocate |
| { |
| public: |
| Relocate() |
| : skip_call_tls_get_addr_(false), |
| local_dynamic_type_(LOCAL_DYNAMIC_NONE) |
| { } |
| |
| ~Relocate() |
| { |
| if (this->skip_call_tls_get_addr_) |
| { |
| // FIXME: This needs to specify the location somehow. |
| gold_error(_("missing expected TLS relocation")); |
| } |
| } |
| |
| // 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); |
| |
| // Do a relocation. Return false if the caller should not issue |
| // any warnings about this relocation. |
| inline bool |
| relocate(const Relocate_info<32, false>*, Target_i386*, size_t relnum, |
| const elfcpp::Rel<32, false>&, |
| unsigned int r_type, const Sized_symbol<32>*, |
| const Symbol_value<32>*, |
| unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, |
| section_size_type); |
| |
| private: |
| // Do a TLS relocation. |
| inline void |
| relocate_tls(const Relocate_info<32, false>*, Target_i386* target, |
| size_t relnum, const elfcpp::Rel<32, false>&, |
| unsigned int r_type, const Sized_symbol<32>*, |
| const Symbol_value<32>*, |
| unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, |
| section_size_type); |
| |
| // Do a TLS General-Dynamic to Initial-Exec transition. |
| inline void |
| tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rel<32, false>&, unsigned int r_type, |
| elfcpp::Elf_types<32>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size); |
| |
| // Do a TLS General-Dynamic to Local-Exec transition. |
| inline void |
| tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rel<32, false>&, unsigned int r_type, |
| elfcpp::Elf_types<32>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size); |
| |
| // Do a TLS Local-Dynamic to Local-Exec transition. |
| inline void |
| tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rel<32, false>&, unsigned int r_type, |
| elfcpp::Elf_types<32>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size); |
| |
| // Do a TLS Initial-Exec to Local-Exec transition. |
| static inline void |
| tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rel<32, false>&, unsigned int r_type, |
| elfcpp::Elf_types<32>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size); |
| |
| // We need to keep track of which type of local dynamic relocation |
| // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly. |
| enum Local_dynamic_type |
| { |
| LOCAL_DYNAMIC_NONE, |
| LOCAL_DYNAMIC_SUN, |
| LOCAL_DYNAMIC_GNU |
| }; |
| |
| // This is set if we should skip the next reloc, which should be a |
| // PLT32 reloc against ___tls_get_addr. |
| bool skip_call_tls_get_addr_; |
| // The type of local dynamic relocation we have seen in the section |
| // being relocated, if any. |
| Local_dynamic_type local_dynamic_type_; |
| }; |
| |
| // 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*); |
| }; |
| |
| // Adjust TLS relocation type based on the options and whether this |
| // is a local symbol. |
| static tls::Tls_optimization |
| optimize_tls_reloc(bool is_final, int r_type); |
| |
| // Get the GOT section, creating it if necessary. |
| Output_data_got<32, false>* |
| 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*); |
| |
| // Create a GOT entry for the TLS module index. |
| unsigned int |
| got_mod_index_entry(Symbol_table* symtab, Layout* layout, |
| Sized_relobj<32, false>* object); |
| |
| // Get the PLT section. |
| const Output_data_plt_i386* |
| plt_section() const |
| { |
| gold_assert(this->plt_ != NULL); |
| return this->plt_; |
| } |
| |
| // Get the dynamic reloc section, creating it if necessary. |
| Reloc_section* |
| rel_dyn_section(Layout*); |
| |
| // Return true if the symbol may need a COPY relocation. |
| // References from an executable object to non-function symbols |
| // defined in a dynamic object may need a COPY relocation. |
| bool |
| may_need_copy_reloc(Symbol* gsym) |
| { |
| return (!parameters->options().shared() |
| && gsym->is_from_dynobj() |
| && gsym->type() != elfcpp::STT_FUNC); |
| } |
| |
| // Copy a relocation against a global symbol. |
| void |
| copy_reloc(const General_options*, Symbol_table*, Layout*, |
| Sized_relobj<32, false>*, unsigned int, |
| Output_section*, Symbol*, const elfcpp::Rel<32, false>&); |
| |
| // Information about this specific target which we pass to the |
| // general Target structure. |
| static const Target::Target_info i386_info; |
| |
| // The types of GOT entries needed for this platform. |
| enum Got_type |
| { |
| GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol |
| GOT_TYPE_TLS_OFFSET = 1, // GOT entry for TLS offset |
| GOT_TYPE_TLS_PAIR = 2, // GOT entry for TLS module/offset pair |
| GOT_TYPE_TLS_DESC = 3 // GOT entry for TLS_DESC pair |
| }; |
| |
| // The GOT section. |
| Output_data_got<32, false>* got_; |
| // The PLT section. |
| Output_data_plt_i386* 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<32, false>* copy_relocs_; |
| // Space for variables copied with a COPY reloc. |
| Output_data_space* dynbss_; |
| // Offset of the GOT entry for the TLS module index; |
| unsigned int got_mod_index_offset_; |
| }; |
| |
| const Target::Target_info Target_i386::i386_info = |
| { |
| 32, // size |
| false, // is_big_endian |
| elfcpp::EM_386, // machine_code |
| false, // has_make_symbol |
| false, // has_resolve |
| true, // has_code_fill |
| true, // is_default_stack_executable |
| "/usr/lib/libc.so.1", // dynamic_linker |
| 0x08048000, // default_text_segment_address |
| 0x1000, // abi_pagesize (overridable by -z max-page-size) |
| 0x1000 // common_pagesize (overridable by -z common-page-size) |
| }; |
| |
| // Get the GOT section, creating it if necessary. |
| |
| Output_data_got<32, false>* |
| Target_i386::got_section(Symbol_table* symtab, Layout* layout) |
| { |
| if (this->got_ == NULL) |
| { |
| gold_assert(symtab != NULL && layout != NULL); |
| |
| this->got_ = new Output_data_got<32, false>(); |
| |
| layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, |
| elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, |
| this->got_); |
| |
| // 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); |
| layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, |
| elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, |
| this->got_plt_); |
| |
| // 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. |
| |
| Target_i386::Reloc_section* |
| Target_i386::rel_dyn_section(Layout* layout) |
| { |
| if (this->rel_dyn_ == NULL) |
| { |
| gold_assert(layout != NULL); |
| this->rel_dyn_ = new Reloc_section(); |
| layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL, |
| elfcpp::SHF_ALLOC, this->rel_dyn_); |
| } |
| return this->rel_dyn_; |
| } |
| |
| // A class to handle the PLT data. |
| |
| class Output_data_plt_i386 : public Output_section_data |
| { |
| public: |
| typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section; |
| |
| Output_data_plt_i386(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); |
| |
| private: |
| // The size of an entry in the PLT. |
| static const int plt_entry_size = 16; |
| |
| // The first entry in the PLT for an executable. |
| static unsigned char exec_first_plt_entry[plt_entry_size]; |
| |
| // The first entry in the PLT for a shared object. |
| static unsigned char dyn_first_plt_entry[plt_entry_size]; |
| |
| // Other entries in the PLT for an executable. |
| static unsigned char exec_plt_entry[plt_entry_size]; |
| |
| // Other entries in the PLT for a shared object. |
| static unsigned char dyn_plt_entry[plt_entry_size]; |
| |
| // Set the final size. |
| void |
| set_final_data_size() |
| { this->set_data_size((this->count_ + 1) * plt_entry_size); } |
| |
| // 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. |
| |
| Output_data_plt_i386::Output_data_plt_i386(Layout* layout, |
| Output_data_space* got_plt) |
| : Output_section_data(4), got_plt_(got_plt), count_(0) |
| { |
| this->rel_ = new Reloc_section(); |
| layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, |
| elfcpp::SHF_ALLOC, this->rel_); |
| } |
| |
| void |
| Output_data_plt_i386::do_adjust_output_section(Output_section* os) |
| { |
| // UnixWare sets the entsize of .plt to 4, and so does the old GNU |
| // linker, and so do we. |
| os->set_entsize(4); |
| } |
| |
| // Add an entry to the PLT. |
| |
| void |
| Output_data_plt_i386::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_ + 1) * plt_entry_size); |
| |
| ++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_386_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. |
| } |
| |
| // The first entry in the PLT for an executable. |
| |
| unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] = |
| { |
| 0xff, 0x35, // pushl contents of memory address |
| 0, 0, 0, 0, // replaced with address of .got + 4 |
| 0xff, 0x25, // jmp indirect |
| 0, 0, 0, 0, // replaced with address of .got + 8 |
| 0, 0, 0, 0 // unused |
| }; |
| |
| // The first entry in the PLT for a shared object. |
| |
| unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] = |
| { |
| 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx) |
| 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx) |
| 0, 0, 0, 0 // unused |
| }; |
| |
| // Subsequent entries in the PLT for an executable. |
| |
| unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] = |
| { |
| 0xff, 0x25, // jmp indirect |
| 0, 0, 0, 0, // replaced with address of symbol in .got |
| 0x68, // pushl immediate |
| 0, 0, 0, 0, // replaced with offset into relocation table |
| 0xe9, // jmp relative |
| 0, 0, 0, 0 // replaced with offset to start of .plt |
| }; |
| |
| // Subsequent entries in the PLT for a shared object. |
| |
| unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] = |
| { |
| 0xff, 0xa3, // jmp *offset(%ebx) |
| 0, 0, 0, 0, // replaced with offset of symbol in .got |
| 0x68, // pushl immediate |
| 0, 0, 0, 0, // replaced with offset into relocation table |
| 0xe9, // jmp relative |
| 0, 0, 0, 0 // replaced with offset to start of .plt |
| }; |
| |
| // Write out the PLT. This uses the hand-coded instructions above, |
| // and adjusts them as needed. This is all specified by the i386 ELF |
| // Processor Supplement. |
| |
| void |
| Output_data_plt_i386::do_write(Output_file* of) |
| { |
| const off_t offset = this->offset(); |
| const section_size_type oview_size = |
| convert_to_section_size_type(this->data_size()); |
| unsigned char* const oview = of->get_output_view(offset, oview_size); |
| |
| const off_t got_file_offset = this->got_plt_->offset(); |
| const section_size_type got_size = |
| convert_to_section_size_type(this->got_plt_->data_size()); |
| unsigned char* const got_view = of->get_output_view(got_file_offset, |
| got_size); |
| |
| unsigned char* pov = oview; |
| |
| elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address(); |
| elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address(); |
| |
| if (parameters->options().shared()) |
| memcpy(pov, dyn_first_plt_entry, plt_entry_size); |
| else |
| { |
| memcpy(pov, exec_first_plt_entry, plt_entry_size); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4); |
| elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8); |
| } |
| pov += plt_entry_size; |
| |
| 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 = plt_entry_size; |
| 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 += plt_entry_size, |
| got_pov += 4, |
| plt_offset += plt_entry_size, |
| plt_rel_offset += rel_size, |
| got_offset += 4) |
| { |
| // Set and adjust the PLT entry itself. |
| |
| if (parameters->options().shared()) |
| { |
| memcpy(pov, dyn_plt_entry, plt_entry_size); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset); |
| } |
| else |
| { |
| memcpy(pov, exec_plt_entry, plt_entry_size); |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, |
| (got_address |
| + got_offset)); |
| } |
| |
| elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset); |
| elfcpp::Swap<32, false>::writeval(pov + 12, |
| - (plt_offset + plt_entry_size)); |
| |
| // Set the entry in the GOT. |
| elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6); |
| } |
| |
| gold_assert(static_cast<section_size_type>(pov - oview) == oview_size); |
| gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size); |
| |
| of->write_output_view(offset, oview_size, oview); |
| of->write_output_view(got_file_offset, got_size, got_view); |
| } |
| |
| // Create a PLT entry for a global symbol. |
| |
| void |
| Target_i386::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_i386(layout, this->got_plt_); |
| layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_EXECINSTR), |
| this->plt_); |
| } |
| |
| this->plt_->add_entry(gsym); |
| } |
| |
| // Create a GOT entry for the TLS module index. |
| |
| unsigned int |
| Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout, |
| Sized_relobj<32, false>* object) |
| { |
| if (this->got_mod_index_offset_ == -1U) |
| { |
| gold_assert(symtab != NULL && layout != NULL && object != NULL); |
| Reloc_section* rel_dyn = this->rel_dyn_section(layout); |
| Output_data_got<32, false>* got = this->got_section(symtab, layout); |
| unsigned int got_offset = got->add_constant(0); |
| rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got, |
| got_offset); |
| got->add_constant(0); |
| this->got_mod_index_offset_ = got_offset; |
| } |
| return this->got_mod_index_offset_; |
| } |
| |
| // Handle a relocation against a non-function symbol defined in a |
| // dynamic object. The traditional way to handle this is to generate |
| // a COPY relocation to copy the variable at runtime from the shared |
| // object into the executable's data segment. However, this is |
| // undesirable in general, as if the size of the object changes in the |
| // dynamic object, the executable will no longer work correctly. If |
| // this relocation is in a writable section, then we can create a |
| // dynamic reloc and the dynamic linker will resolve it to the correct |
| // address at runtime. However, we do not want do that if the |
| // relocation is in a read-only section, as it would prevent the |
| // readonly segment from being shared. And if we have to eventually |
| // generate a COPY reloc, then any dynamic relocations will be |
| // useless. So this means that if this is a writable section, we need |
| // to save the relocation until we see whether we have to create a |
| // COPY relocation for this symbol for any other relocation. |
| |
| void |
| Target_i386::copy_reloc(const General_options* options, |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<32, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| Symbol* gsym, |
| const elfcpp::Rel<32, false>& rel) |
| { |
| Sized_symbol<32>* ssym = symtab->get_sized_symbol<32>(gsym); |
| |
| if (!Copy_relocs<32, false>::need_copy_reloc(options, object, |
| data_shndx, ssym)) |
| { |
| // So far we do not need a COPY reloc. Save this relocation. |
| // If it turns out that we never need a COPY reloc for this |
| // symbol, then we will emit the relocation. |
| if (this->copy_relocs_ == NULL) |
| this->copy_relocs_ = new Copy_relocs<32, false>(); |
| this->copy_relocs_->save(ssym, object, data_shndx, output_section, rel); |
| } |
| else |
| { |
| // Allocate space for this symbol in the .bss section. |
| |
| elfcpp::Elf_types<32>::Elf_WXword symsize = ssym->symsize(); |
| |
| // There is no defined way to determine the required alignment |
| // of the symbol. We pick the alignment based on the size. We |
| // set an arbitrary maximum of 256. |
| unsigned int align; |
| for (align = 1; align < 512; align <<= 1) |
| if ((symsize & align) != 0) |
| break; |
| |
| if (this->dynbss_ == NULL) |
| { |
| this->dynbss_ = new Output_data_space(align); |
| layout->add_output_section_data(".bss", |
| elfcpp::SHT_NOBITS, |
| (elfcpp::SHF_ALLOC |
| | elfcpp::SHF_WRITE), |
| this->dynbss_); |
| } |
| |
| Output_data_space* dynbss = this->dynbss_; |
| |
| if (align > dynbss->addralign()) |
| dynbss->set_space_alignment(align); |
| |
| section_size_type dynbss_size = |
| convert_to_section_size_type(dynbss->current_data_size()); |
| dynbss_size = align_address(dynbss_size, align); |
| section_size_type offset = dynbss_size; |
| dynbss->set_current_data_size(dynbss_size + symsize); |
| |
| symtab->define_with_copy_reloc(ssym, dynbss, offset); |
| |
| // Add the COPY reloc. |
| Reloc_section* rel_dyn = this->rel_dyn_section(layout); |
| rel_dyn->add_global(ssym, elfcpp::R_386_COPY, dynbss, offset); |
| } |
| } |
| |
| // Optimize the TLS relocation type based on what we know about the |
| // symbol. IS_FINAL is true if the final address of this symbol is |
| // known at link time. |
| |
| tls::Tls_optimization |
| Target_i386::optimize_tls_reloc(bool is_final, int r_type) |
| { |
| // If we are generating a shared library, then we can't do anything |
| // in the linker. |
| if (parameters->options().shared()) |
| return tls::TLSOPT_NONE; |
| |
| switch (r_type) |
| { |
| case elfcpp::R_386_TLS_GD: |
| case elfcpp::R_386_TLS_GOTDESC: |
| case elfcpp::R_386_TLS_DESC_CALL: |
| // These are General-Dynamic which permits fully general TLS |
| // access. Since we know that we are generating an executable, |
| // we can convert this to Initial-Exec. If we also know that |
| // this is a local symbol, we can further switch to Local-Exec. |
| if (is_final) |
| return tls::TLSOPT_TO_LE; |
| return tls::TLSOPT_TO_IE; |
| |
| case elfcpp::R_386_TLS_LDM: |
| // This is Local-Dynamic, which refers to a local symbol in the |
| // dynamic TLS block. Since we know that we generating an |
| // executable, we can switch to Local-Exec. |
| return tls::TLSOPT_TO_LE; |
| |
| case elfcpp::R_386_TLS_LDO_32: |
| // Another type of Local-Dynamic relocation. |
| return tls::TLSOPT_TO_LE; |
| |
| case elfcpp::R_386_TLS_IE: |
| case elfcpp::R_386_TLS_GOTIE: |
| case elfcpp::R_386_TLS_IE_32: |
| // These are Initial-Exec relocs which get the thread offset |
| // from the GOT. If we know that we are linking against the |
| // local symbol, we can switch to Local-Exec, which links the |
| // thread offset into the instruction. |
| if (is_final) |
| return tls::TLSOPT_TO_LE; |
| return tls::TLSOPT_NONE; |
| |
| case elfcpp::R_386_TLS_LE: |
| case elfcpp::R_386_TLS_LE_32: |
| // When we already have Local-Exec, there is nothing further we |
| // can do. |
| return tls::TLSOPT_NONE; |
| |
| default: |
| gold_unreachable(); |
| } |
| } |
| |
| // Report an unsupported relocation against a local symbol. |
| |
| void |
| Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object, |
| unsigned int r_type) |
| { |
| gold_error(_("%s: unsupported reloc %u against local symbol"), |
| object->name().c_str(), r_type); |
| } |
| |
| // Scan a relocation for a local symbol. |
| |
| inline void |
| Target_i386::Scan::local(const General_options&, |
| Symbol_table* symtab, |
| Layout* layout, |
| Target_i386* target, |
| Sized_relobj<32, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, false>& reloc, |
| unsigned int r_type, |
| const elfcpp::Sym<32, false>& lsym) |
| { |
| switch (r_type) |
| { |
| case elfcpp::R_386_NONE: |
| case elfcpp::R_386_GNU_VTINHERIT: |
| case elfcpp::R_386_GNU_VTENTRY: |
| break; |
| |
| case elfcpp::R_386_32: |
| // 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_386_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()); |
| rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE, |
| output_section, data_shndx, |
| reloc.get_r_offset()); |
| } |
| break; |
| |
| case elfcpp::R_386_16: |
| case elfcpp::R_386_8: |
| // If building a shared library (or a position-independent |
| // executable), we need to create a dynamic relocation for |
| // this location. Because the addend needs to remain in the |
| // data section, we need to be careful not to apply this |
| // relocation statically. |
| if (parameters->options().output_is_position_independent()) |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| if (lsym.get_st_type() != elfcpp::STT_SECTION) |
| { |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| rel_dyn->add_local(object, r_sym, r_type, output_section, |
| data_shndx, reloc.get_r_offset()); |
| } |
| else |
| { |
| gold_assert(lsym.get_st_value() == 0); |
| rel_dyn->add_local_section(object, lsym.get_st_shndx(), |
| r_type, output_section, |
| data_shndx, reloc.get_r_offset()); |
| } |
| } |
| break; |
| |
| case elfcpp::R_386_PC32: |
| case elfcpp::R_386_PC16: |
| case elfcpp::R_386_PC8: |
| break; |
| |
| case elfcpp::R_386_PLT32: |
| // Since we know this is a local symbol, we can handle this as a |
| // PC32 reloc. |
| break; |
| |
| case elfcpp::R_386_GOTOFF: |
| case elfcpp::R_386_GOTPC: |
| // We need a GOT section. |
| target->got_section(symtab, layout); |
| break; |
| |
| case elfcpp::R_386_GOT32: |
| { |
| // The symbol requires a GOT entry. |
| Output_data_got<32, false>* 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_386_RELATIVE, got, |
| object->local_got_offset(r_sym, GOT_TYPE_STANDARD)); |
| } |
| } |
| } |
| break; |
| |
| // These are relocations which should only be seen by the |
| // dynamic linker, and should never be seen here. |
| case elfcpp::R_386_COPY: |
| case elfcpp::R_386_GLOB_DAT: |
| case elfcpp::R_386_JUMP_SLOT: |
| case elfcpp::R_386_RELATIVE: |
| case elfcpp::R_386_TLS_TPOFF: |
| case elfcpp::R_386_TLS_DTPMOD32: |
| case elfcpp::R_386_TLS_DTPOFF32: |
| case elfcpp::R_386_TLS_TPOFF32: |
| case elfcpp::R_386_TLS_DESC: |
| gold_error(_("%s: unexpected reloc %u in object file"), |
| object->name().c_str(), r_type); |
| break; |
| |
| // These are initial TLS relocs, which are expected when |
| // linking. |
| case elfcpp::R_386_TLS_GD: // Global-dynamic |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| case elfcpp::R_386_TLS_DESC_CALL: |
| case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_IE_32: |
| case elfcpp::R_386_TLS_GOTIE: |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| case elfcpp::R_386_TLS_LE_32: |
| { |
| bool output_is_shared = parameters->options().shared(); |
| const tls::Tls_optimization optimized_type |
| = Target_i386::optimize_tls_reloc(!output_is_shared, r_type); |
| switch (r_type) |
| { |
| case elfcpp::R_386_TLS_GD: // Global-dynamic |
| if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // Create a pair of GOT entries for the module index and |
| // dtv-relative offset. |
| Output_data_got<32, false>* got |
| = target->got_section(symtab, layout); |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| got->add_local_pair_with_rel(object, r_sym, |
| lsym.get_st_shndx(), |
| GOT_TYPE_TLS_PAIR, |
| target->rel_dyn_section(layout), |
| elfcpp::R_386_TLS_DTPMOD32, 0); |
| } |
| else if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_local(object, r_type); |
| break; |
| |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva) |
| case elfcpp::R_386_TLS_DESC_CALL: |
| // FIXME: If not relaxing to LE, we need to generate |
| // a GOT entry with an R_386_TLS_DESC reloc. |
| if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_local(object, r_type); |
| break; |
| |
| case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // Create a GOT entry for the module index. |
| target->got_mod_index_entry(symtab, layout, object); |
| } |
| else if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_local(object, r_type); |
| break; |
| |
| case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| break; |
| |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_IE_32: |
| case elfcpp::R_386_TLS_GOTIE: |
| layout->set_has_static_tls(); |
| if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // For the R_386_TLS_IE relocation, we need to create a |
| // dynamic relocation when building a shared library. |
| if (r_type == elfcpp::R_386_TLS_IE |
| && parameters->options().shared()) |
| { |
| 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_386_RELATIVE, |
| output_section, data_shndx, |
| reloc.get_r_offset()); |
| } |
| // Create a GOT entry for the tp-relative offset. |
| Output_data_got<32, false>* got |
| = target->got_section(symtab, layout); |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| ? elfcpp::R_386_TLS_TPOFF32 |
| : elfcpp::R_386_TLS_TPOFF); |
| got->add_local_with_rel(object, r_sym, GOT_TYPE_TLS_OFFSET, |
| target->rel_dyn_section(layout), |
| dyn_r_type); |
| } |
| else if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_local(object, r_type); |
| break; |
| |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| case elfcpp::R_386_TLS_LE_32: |
| layout->set_has_static_tls(); |
| if (output_is_shared) |
| { |
| // We need to create a dynamic relocation. |
| gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION); |
| unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32 |
| ? elfcpp::R_386_TLS_TPOFF32 |
| : elfcpp::R_386_TLS_TPOFF); |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_local(object, r_sym, dyn_r_type, output_section, |
| data_shndx, reloc.get_r_offset()); |
| } |
| break; |
| |
| default: |
| gold_unreachable(); |
| } |
| } |
| break; |
| |
| case elfcpp::R_386_32PLT: |
| case elfcpp::R_386_TLS_GD_32: |
| case elfcpp::R_386_TLS_GD_PUSH: |
| case elfcpp::R_386_TLS_GD_CALL: |
| case elfcpp::R_386_TLS_GD_POP: |
| case elfcpp::R_386_TLS_LDM_32: |
| case elfcpp::R_386_TLS_LDM_PUSH: |
| case elfcpp::R_386_TLS_LDM_CALL: |
| case elfcpp::R_386_TLS_LDM_POP: |
| case elfcpp::R_386_USED_BY_INTEL_200: |
| default: |
| unsupported_reloc_local(object, r_type); |
| break; |
| } |
| } |
| |
| // Report an unsupported relocation against a global symbol. |
| |
| void |
| Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* 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. |
| |
| inline void |
| Target_i386::Scan::global(const General_options& options, |
| Symbol_table* symtab, |
| Layout* layout, |
| Target_i386* target, |
| Sized_relobj<32, false>* object, |
| unsigned int data_shndx, |
| Output_section* output_section, |
| const elfcpp::Rel<32, false>& reloc, |
| unsigned int r_type, |
| Symbol* gsym) |
| { |
| switch (r_type) |
| { |
| case elfcpp::R_386_NONE: |
| case elfcpp::R_386_GNU_VTINHERIT: |
| case elfcpp::R_386_GNU_VTENTRY: |
| break; |
| |
| case elfcpp::R_386_32: |
| case elfcpp::R_386_16: |
| case elfcpp::R_386_8: |
| { |
| // Make a PLT entry if necessary. |
| if (gsym->needs_plt_entry()) |
| { |
| target->make_plt_entry(symtab, layout, gsym); |
| // Since this is not a PC-relative relocation, we may be |
| // taking the address of a function. In that case we need to |
| // set the entry in the dynamic symbol table to the address of |
| // the PLT entry. |
| if (gsym->is_from_dynobj() && !parameters->options().shared()) |
| gsym->set_needs_dynsym_value(); |
| } |
| // Make a dynamic relocation if necessary. |
| if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF)) |
| { |
| if (target->may_need_copy_reloc(gsym)) |
| { |
| target->copy_reloc(&options, symtab, layout, object, |
| data_shndx, output_section, gsym, reloc); |
| } |
| else if (r_type == elfcpp::R_386_32 |
| && gsym->can_use_relative_reloc(false)) |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE, |
| output_section, object, |
| data_shndx, reloc.get_r_offset()); |
| } |
| else |
| { |
| 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_386_PC32: |
| case elfcpp::R_386_PC16: |
| case elfcpp::R_386_PC8: |
| { |
| // Make a PLT entry if necessary. |
| if (gsym->needs_plt_entry()) |
| { |
| // These relocations are used for function calls only in |
| // non-PIC code. For a 32-bit relocation in a shared library, |
| // we'll need a text relocation anyway, so we can skip the |
| // PLT entry and let the dynamic linker bind the call directly |
| // to the target. For smaller relocations, we should use a |
| // PLT entry to ensure that the call can reach. |
| if (!parameters->options().shared() |
| || r_type != elfcpp::R_386_PC32) |
| 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) |
| flags |= Symbol::FUNCTION_CALL; |
| if (gsym->needs_dynamic_reloc(flags)) |
| { |
| if (target->may_need_copy_reloc(gsym)) |
| { |
| target->copy_reloc(&options, symtab, layout, object, |
| data_shndx, output_section, gsym, reloc); |
| } |
| else |
| { |
| 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_386_GOT32: |
| { |
| // The symbol requires a GOT entry. |
| Output_data_got<32, false>* 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_386_GLOB_DAT); |
| else |
| { |
| if (got->add_global(gsym, GOT_TYPE_STANDARD)) |
| rel_dyn->add_global_relative( |
| gsym, elfcpp::R_386_RELATIVE, got, |
| gsym->got_offset(GOT_TYPE_STANDARD)); |
| } |
| } |
| } |
| break; |
| |
| case elfcpp::R_386_PLT32: |
| // If the symbol is fully resolved, this is just a PC32 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_386_GOTOFF: |
| case elfcpp::R_386_GOTPC: |
| // We need a GOT section. |
| target->got_section(symtab, layout); |
| break; |
| |
| // These are relocations which should only be seen by the |
| // dynamic linker, and should never be seen here. |
| case elfcpp::R_386_COPY: |
| case elfcpp::R_386_GLOB_DAT: |
| case elfcpp::R_386_JUMP_SLOT: |
| case elfcpp::R_386_RELATIVE: |
| case elfcpp::R_386_TLS_TPOFF: |
| case elfcpp::R_386_TLS_DTPMOD32: |
| case elfcpp::R_386_TLS_DTPOFF32: |
| case elfcpp::R_386_TLS_TPOFF32: |
| case elfcpp::R_386_TLS_DESC: |
| gold_error(_("%s: unexpected reloc %u in object file"), |
| object->name().c_str(), r_type); |
| break; |
| |
| // These are initial tls relocs, which are expected when |
| // linking. |
| case elfcpp::R_386_TLS_GD: // Global-dynamic |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| case elfcpp::R_386_TLS_DESC_CALL: |
| case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_IE_32: |
| case elfcpp::R_386_TLS_GOTIE: |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| case elfcpp::R_386_TLS_LE_32: |
| { |
| const bool is_final = gsym->final_value_is_known(); |
| const tls::Tls_optimization optimized_type |
| = Target_i386::optimize_tls_reloc(is_final, r_type); |
| switch (r_type) |
| { |
| case elfcpp::R_386_TLS_GD: // Global-dynamic |
| if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // Create a pair of GOT entries for the module index and |
| // dtv-relative offset. |
| Output_data_got<32, false>* got |
| = target->got_section(symtab, layout); |
| got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR, |
| target->rel_dyn_section(layout), |
| elfcpp::R_386_TLS_DTPMOD32, |
| elfcpp::R_386_TLS_DTPOFF32); |
| } |
| else if (optimized_type == tls::TLSOPT_TO_IE) |
| { |
| // Create a GOT entry for the tp-relative offset. |
| Output_data_got<32, false>* got |
| = target->got_section(symtab, layout); |
| got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET, |
| target->rel_dyn_section(layout), |
| elfcpp::R_386_TLS_TPOFF32); |
| } |
| else if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_global(object, r_type, gsym); |
| break; |
| |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url) |
| case elfcpp::R_386_TLS_DESC_CALL: |
| // FIXME: If not relaxing to LE, we need to generate |
| // a GOT entry with an R_386_TLS_DESC reloc. |
| if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_global(object, r_type, gsym); |
| unsupported_reloc_global(object, r_type, gsym); |
| break; |
| |
| case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // Create a GOT entry for the module index. |
| target->got_mod_index_entry(symtab, layout, object); |
| } |
| else if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_global(object, r_type, gsym); |
| break; |
| |
| case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| break; |
| |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_IE_32: |
| case elfcpp::R_386_TLS_GOTIE: |
| layout->set_has_static_tls(); |
| if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // For the R_386_TLS_IE relocation, we need to create a |
| // dynamic relocation when building a shared library. |
| if (r_type == elfcpp::R_386_TLS_IE |
| && parameters->options().shared()) |
| { |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE, |
| output_section, object, |
| data_shndx, |
| reloc.get_r_offset()); |
| } |
| // Create a GOT entry for the tp-relative offset. |
| Output_data_got<32, false>* got |
| = target->got_section(symtab, layout); |
| unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| ? elfcpp::R_386_TLS_TPOFF32 |
| : elfcpp::R_386_TLS_TPOFF); |
| got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET, |
| target->rel_dyn_section(layout), |
| dyn_r_type); |
| } |
| else if (optimized_type != tls::TLSOPT_TO_LE) |
| unsupported_reloc_global(object, r_type, gsym); |
| break; |
| |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| case elfcpp::R_386_TLS_LE_32: |
| layout->set_has_static_tls(); |
| if (parameters->options().shared()) |
| { |
| // We need to create a dynamic relocation. |
| unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32 |
| ? elfcpp::R_386_TLS_TPOFF32 |
| : elfcpp::R_386_TLS_TPOFF); |
| Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| rel_dyn->add_global(gsym, dyn_r_type, output_section, object, |
| data_shndx, reloc.get_r_offset()); |
| } |
| break; |
| |
| default: |
| gold_unreachable(); |
| } |
| } |
| break; |
| |
| case elfcpp::R_386_32PLT: |
| case elfcpp::R_386_TLS_GD_32: |
| case elfcpp::R_386_TLS_GD_PUSH: |
| case elfcpp::R_386_TLS_GD_CALL: |
| case elfcpp::R_386_TLS_GD_POP: |
| case elfcpp::R_386_TLS_LDM_32: |
| case elfcpp::R_386_TLS_LDM_PUSH: |
| case elfcpp::R_386_TLS_LDM_CALL: |
| case elfcpp::R_386_TLS_LDM_POP: |
| case elfcpp::R_386_USED_BY_INTEL_200: |
| default: |
| unsupported_reloc_global(object, r_type, gsym); |
| break; |
| } |
| } |
| |
| // Scan relocations for a section. |
| |
| void |
| Target_i386::scan_relocs(const General_options& options, |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<32, false>* 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) |
| { |
| if (sh_type == elfcpp::SHT_RELA) |
| { |
| gold_error(_("%s: unsupported RELA reloc section"), |
| object->name().c_str()); |
| return; |
| } |
| |
| gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL, |
| Target_i386::Scan>( |
| options, |
| symtab, |
| layout, |
| this, |
| object, |
| data_shndx, |
| prelocs, |
| reloc_count, |
| output_section, |
| needs_special_offset_handling, |
| local_symbol_count, |
| plocal_symbols); |
| } |
| |
| // Finalize the sections. |
| |
| void |
| Target_i386::do_finalize_sections(Layout* layout) |
| { |
| // Fill in some more dynamic tags. |
| Output_data_dynamic* const odyn = layout->dynamic_data(); |
| if (odyn != NULL) |
| { |
| if (this->got_plt_ != NULL) |
| odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_); |
| |
| if (this->plt_ != NULL) |
| { |
| const Output_data* od = this->plt_->rel_plt(); |
| odyn->add_section_size(elfcpp::DT_PLTRELSZ, od); |
| odyn->add_section_address(elfcpp::DT_JMPREL, od); |
| odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL); |
| } |
| |
| if (this->rel_dyn_ != NULL) |
| { |
| const Output_data* od = this->rel_dyn_; |
| odyn->add_section_address(elfcpp::DT_REL, od); |
| odyn->add_section_size(elfcpp::DT_RELSZ, od); |
| odyn->add_constant(elfcpp::DT_RELENT, |
| elfcpp::Elf_sizes<32>::rel_size); |
| } |
| |
| if (!parameters->options().shared()) |
| { |
| // The value of the DT_DEBUG tag is filled in by the dynamic |
| // linker at run time, and used by the debugger. |
| odyn->add_constant(elfcpp::DT_DEBUG, 0); |
| } |
| } |
| |
| // Emit any relocs we saved in an attempt to avoid generating COPY |
| // relocs. |
| if (this->copy_relocs_ == NULL) |
| return; |
| if (this->copy_relocs_->any_to_emit()) |
| { |
| Reloc_section* rel_dyn = this->rel_dyn_section(layout); |
| this->copy_relocs_->emit(rel_dyn); |
| } |
| delete this->copy_relocs_; |
| this->copy_relocs_ = NULL; |
| } |
| |
| // 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_386_RELATIVE, the addend |
| // of the relocation is carried in the data, and we must not |
| // apply the static relocation. |
| |
| inline bool |
| Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym, |
| int ref_flags, |
| bool is_32bit) |
| { |
| // 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. |
| |
| inline bool |
| Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo, |
| Target_i386* target, |
| size_t relnum, |
| const elfcpp::Rel<32, false>& rel, |
| unsigned int r_type, |
| const Sized_symbol<32>* gsym, |
| const Symbol_value<32>* psymval, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr address, |
| section_size_type view_size) |
| { |
| if (this->skip_call_tls_get_addr_) |
| { |
| if (r_type != elfcpp::R_386_PLT32 |
| || gsym == NULL |
| || strcmp(gsym->name(), "___tls_get_addr") != 0) |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("missing expected TLS relocation")); |
| else |
| { |
| this->skip_call_tls_get_addr_ = false; |
| return false; |
| } |
| } |
| |
| // Pick the value to use for symbols defined in shared objects. |
| Symbol_value<32> symval; |
| bool is_nonpic = (r_type == elfcpp::R_386_PC8 |
| || r_type == elfcpp::R_386_PC16 |
| || r_type == elfcpp::R_386_PC32); |
| if (gsym != NULL |
| && (gsym->is_from_dynobj() |
| || (parameters->options().shared() |
| && (gsym->is_undefined() || gsym->is_preemptible()))) |
| && gsym->has_plt_offset() |
| && (!is_nonpic || !parameters->options().shared())) |
| { |
| symval.set_output_value(target->plt_section()->address() |
| + gsym->plt_offset()); |
| psymval = &symval; |
| } |
| |
| const Sized_relobj<32, false>* object = relinfo->object; |
| |
| // Get the GOT offset if needed. |
| // The GOT pointer points to the end of the GOT section. |
| // We need to subtract the size of the GOT section to get |
| // the actual offset to use in the relocation. |
| bool have_got_offset = false; |
| unsigned int got_offset = 0; |
| switch (r_type) |
| { |
| case elfcpp::R_386_GOT32: |
| 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; |
| } |
| |
| switch (r_type) |
| { |
| case elfcpp::R_386_NONE: |
| case elfcpp::R_386_GNU_VTINHERIT: |
| case elfcpp::R_386_GNU_VTENTRY: |
| break; |
| |
| case elfcpp::R_386_32: |
| if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true)) |
| Relocate_functions<32, false>::rel32(view, object, psymval); |
| break; |
| |
| case elfcpp::R_386_PC32: |
| { |
| int ref_flags = Symbol::NON_PIC_REF; |
| if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC) |
| ref_flags |= Symbol::FUNCTION_CALL; |
| if (should_apply_static_reloc(gsym, ref_flags, true)) |
| Relocate_functions<32, false>::pcrel32(view, object, psymval, address); |
| } |
| break; |
| |
| case elfcpp::R_386_16: |
| if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false)) |
| Relocate_functions<32, false>::rel16(view, object, psymval); |
| break; |
| |
| case elfcpp::R_386_PC16: |
| { |
| int ref_flags = Symbol::NON_PIC_REF; |
| if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC) |
| ref_flags |= Symbol::FUNCTION_CALL; |
| if (should_apply_static_reloc(gsym, ref_flags, false)) |
| Relocate_functions<32, false>::pcrel32(view, object, psymval, address); |
| } |
| break; |
| |
| case elfcpp::R_386_8: |
| if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false)) |
| Relocate_functions<32, false>::rel8(view, object, psymval); |
| break; |
| |
| case elfcpp::R_386_PC8: |
| { |
| int ref_flags = Symbol::NON_PIC_REF; |
| if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC) |
| ref_flags |= Symbol::FUNCTION_CALL; |
| if (should_apply_static_reloc(gsym, ref_flags, false)) |
| Relocate_functions<32, false>::pcrel32(view, object, psymval, address); |
| } |
| break; |
| |
| case elfcpp::R_386_PLT32: |
| gold_assert(gsym == NULL |
| || gsym->has_plt_offset() |
| || gsym->final_value_is_known() |
| || (gsym->is_defined() |
| && !gsym->is_from_dynobj() |
| && !gsym->is_preemptible())); |
| Relocate_functions<32, false>::pcrel32(view, object, psymval, address); |
| break; |
| |
| case elfcpp::R_386_GOT32: |
| gold_assert(have_got_offset); |
| Relocate_functions<32, false>::rel32(view, got_offset); |
| break; |
| |
| case elfcpp::R_386_GOTOFF: |
| { |
| elfcpp::Elf_types<32>::Elf_Addr value; |
| value = (psymval->value(object, 0) |
| - target->got_plt_section()->address()); |
| Relocate_functions<32, false>::rel32(view, value); |
| } |
| break; |
| |
| case elfcpp::R_386_GOTPC: |
| { |
| elfcpp::Elf_types<32>::Elf_Addr value; |
| value = target->got_plt_section()->address(); |
| Relocate_functions<32, false>::pcrel32(view, value, address); |
| } |
| break; |
| |
| case elfcpp::R_386_COPY: |
| case elfcpp::R_386_GLOB_DAT: |
| case elfcpp::R_386_JUMP_SLOT: |
| case elfcpp::R_386_RELATIVE: |
| // These are outstanding tls relocs, which are unexpected when |
| // linking. |
| case elfcpp::R_386_TLS_TPOFF: |
| case elfcpp::R_386_TLS_DTPMOD32: |
| case elfcpp::R_386_TLS_DTPOFF32: |
| case elfcpp::R_386_TLS_TPOFF32: |
| case elfcpp::R_386_TLS_DESC: |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("unexpected reloc %u in object file"), |
| r_type); |
| break; |
| |
| // These are initial tls relocs, which are expected when |
| // linking. |
| case elfcpp::R_386_TLS_GD: // Global-dynamic |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| case elfcpp::R_386_TLS_DESC_CALL: |
| case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_IE_32: |
| case elfcpp::R_386_TLS_GOTIE: |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| case elfcpp::R_386_TLS_LE_32: |
| this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval, |
| view, address, view_size); |
| break; |
| |
| case elfcpp::R_386_32PLT: |
| case elfcpp::R_386_TLS_GD_32: |
| case elfcpp::R_386_TLS_GD_PUSH: |
| case elfcpp::R_386_TLS_GD_CALL: |
| case elfcpp::R_386_TLS_GD_POP: |
| case elfcpp::R_386_TLS_LDM_32: |
| case elfcpp::R_386_TLS_LDM_PUSH: |
| case elfcpp::R_386_TLS_LDM_CALL: |
| case elfcpp::R_386_TLS_LDM_POP: |
| case elfcpp::R_386_USED_BY_INTEL_200: |
| default: |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("unsupported reloc %u"), |
| r_type); |
| break; |
| } |
| |
| return true; |
| } |
| |
| // Perform a TLS relocation. |
| |
| inline void |
| Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo, |
| Target_i386* target, |
| size_t relnum, |
| const elfcpp::Rel<32, false>& rel, |
| unsigned int r_type, |
| const Sized_symbol<32>* gsym, |
| const Symbol_value<32>* psymval, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr, |
| section_size_type view_size) |
| { |
| Output_segment* tls_segment = relinfo->layout->tls_segment(); |
| |
| const Sized_relobj<32, false>* object = relinfo->object; |
| |
| elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0); |
| |
| const bool is_final = |
| (gsym == NULL |
| ? !parameters->options().output_is_position_independent() |
| : gsym->final_value_is_known()); |
| const tls::Tls_optimization optimized_type |
| = Target_i386::optimize_tls_reloc(is_final, r_type); |
| switch (r_type) |
| { |
| case elfcpp::R_386_TLS_GD: // Global-dynamic |
| if (optimized_type == tls::TLSOPT_TO_LE) |
| { |
| gold_assert(tls_segment != NULL); |
| this->tls_gd_to_le(relinfo, relnum, tls_segment, |
| rel, r_type, value, view, |
| view_size); |
| break; |
| } |
| else |
| { |
| unsigned int got_offset; |
| if (gsym != NULL) |
| { |
| gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_PAIR)); |
| got_offset = (gsym->got_offset(GOT_TYPE_TLS_PAIR) |
| - 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_TLS_PAIR)); |
| got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_PAIR) |
| - target->got_size()); |
| } |
| if (optimized_type == tls::TLSOPT_TO_IE) |
| { |
| gold_assert(tls_segment != NULL); |
| this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type, |
| got_offset, view, view_size); |
| break; |
| } |
| else if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // Relocate the field with the offset of the pair of GOT |
| // entries. |
| Relocate_functions<32, false>::rel32(view, got_offset); |
| break; |
| } |
| } |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("unsupported reloc %u"), |
| r_type); |
| break; |
| |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| case elfcpp::R_386_TLS_DESC_CALL: |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("unsupported reloc %u"), |
| r_type); |
| break; |
| |
| case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN) |
| { |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("both SUN and GNU model " |
| "TLS relocations")); |
| break; |
| } |
| this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU; |
| if (optimized_type == tls::TLSOPT_TO_LE) |
| { |
| gold_assert(tls_segment != NULL); |
| this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type, |
| value, view, view_size); |
| break; |
| } |
| else if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // Relocate the field with the offset of the GOT entry for |
| // the module index. |
| unsigned int got_offset; |
| got_offset = (target->got_mod_index_entry(NULL, NULL, NULL) |
| - target->got_size()); |
| Relocate_functions<32, false>::rel32(view, got_offset); |
| break; |
| } |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("unsupported reloc %u"), |
| r_type); |
| break; |
| |
| case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| // This reloc can appear in debugging sections, in which case we |
| // won't see the TLS_LDM reloc. The local_dynamic_type field |
| // tells us this. |
| if (optimized_type == tls::TLSOPT_TO_LE) |
| { |
| gold_assert(tls_segment != NULL); |
| value -= tls_segment->memsz(); |
| } |
| Relocate_functions<32, false>::rel32(view, value); |
| break; |
| |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_GOTIE: |
| case elfcpp::R_386_TLS_IE_32: |
| if (optimized_type == tls::TLSOPT_TO_LE) |
| { |
| gold_assert(tls_segment != NULL); |
| Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment, |
| rel, r_type, value, view, |
| view_size); |
| break; |
| } |
| else if (optimized_type == tls::TLSOPT_NONE) |
| { |
| // Relocate the field with the offset of the GOT entry for |
| // the tp-relative offset of the symbol. |
| unsigned int got_offset; |
| if (gsym != NULL) |
| { |
| gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET)); |
| got_offset = gsym->got_offset(GOT_TYPE_TLS_OFFSET); |
| } |
| 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_TLS_OFFSET)); |
| got_offset = object->local_got_offset(r_sym, |
| GOT_TYPE_TLS_OFFSET); |
| } |
| // For the R_386_TLS_IE relocation, we need to apply the |
| // absolute address of the GOT entry. |
| if (r_type == elfcpp::R_386_TLS_IE) |
| got_offset += target->got_plt_section()->address(); |
| // All GOT offsets are relative to the end of the GOT. |
| got_offset -= target->got_size(); |
| Relocate_functions<32, false>::rel32(view, got_offset); |
| break; |
| } |
| gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| _("unsupported reloc %u"), |
| r_type); |
| break; |
| |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| // If we're creating a shared library, a dynamic relocation will |
| // have been created for this location, so do not apply it now. |
| if (!parameters->options().shared()) |
| { |
| gold_assert(tls_segment != NULL); |
| value -= tls_segment->memsz(); |
| Relocate_functions<32, false>::rel32(view, value); |
| } |
| break; |
| |
| case elfcpp::R_386_TLS_LE_32: |
| // If we're creating a shared library, a dynamic relocation will |
| // have been created for this location, so do not apply it now. |
| if (!parameters->options().shared()) |
| { |
| gold_assert(tls_segment != NULL); |
| value = tls_segment->memsz() - value; |
| Relocate_functions<32, false>::rel32(view, value); |
| } |
| break; |
| } |
| } |
| |
| // Do a relocation in which we convert a TLS General-Dynamic to a |
| // Local-Exec. |
| |
| inline void |
| Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo, |
| size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rel<32, false>& rel, |
| unsigned int, |
| elfcpp::Elf_types<32>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size) |
| { |
| // leal foo(,%reg,1),%eax; call ___tls_get_addr |
| // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax |
| // leal foo(%reg),%eax; call ___tls_get_addr |
| // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax |
| |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9); |
| |
| unsigned char op1 = view[-1]; |
| unsigned char op2 = view[-2]; |
| |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| op2 == 0x8d || op2 == 0x04); |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8); |
| |
| int roff = 5; |
| |
| if (op2 == 0x04) |
| { |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3); |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d); |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| ((op1 & 0xc7) == 0x05 && op1 != (4 << 3))); |
| memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12); |
| } |
| else |
| { |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| (op1 & 0xf8) == 0x80 && (op1 & 7) != 4); |
| if (rel.get_r_offset() + 9 < view_size |
| && view[9] == 0x90) |
| { |
| // There is a trailing nop. Use the size byte subl. |
| memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12); |
| roff = 6; |
| } |
| else |
| { |
| // Use the five byte subl. |
| memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11); |
| } |
| } |
| |
| value = tls_segment->memsz() - value; |
| Relocate_functions<32, false>::rel32(view + roff, value); |
| |
| // The next reloc should be a PLT32 reloc against __tls_get_addr. |
| // We can skip it. |
| this->skip_call_tls_get_addr_ = true; |
| } |
| |
| // Do a relocation in which we convert a TLS General-Dynamic to an |
| // Initial-Exec. |
| |
| inline void |
| Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo, |
| size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rel<32, false>& rel, |
| unsigned int, |
| elfcpp::Elf_types<32>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size) |
| { |
| // leal foo(,%ebx,1),%eax; call ___tls_get_addr |
| // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax |
| |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9); |
| |
| unsigned char op1 = view[-1]; |
| unsigned char op2 = view[-2]; |
| |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| op2 == 0x8d || op2 == 0x04); |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8); |
| |
| int roff = 5; |
| |
| // FIXME: For now, support only one form. |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| op1 == 0x8d && op2 == 0x04); |
| |
| if (op2 == 0x04) |
| { |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3); |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d); |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| ((op1 & 0xc7) == 0x05 && op1 != (4 << 3))); |
| memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12); |
| } |
| else |
| { |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| (op1 & 0xf8) == 0x80 && (op1 & 7) != 4); |
| if (rel.get_r_offset() + 9 < view_size |
| && view[9] == 0x90) |
| { |
| // FIXME: This is not the right instruction sequence. |
| // There is a trailing nop. Use the size byte subl. |
| memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12); |
| roff = 6; |
| } |
| else |
| { |
| // FIXME: This is not the right instruction sequence. |
| // Use the five byte subl. |
| memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11); |
| } |
| } |
| |
| value = tls_segment->memsz() - value; |
| Relocate_functions<32, false>::rel32(view + roff, value); |
| |
| // The next reloc should be a PLT32 reloc against __tls_get_addr. |
| // We can skip it. |
| this->skip_call_tls_get_addr_ = true; |
| } |
| |
| // Do a relocation in which we convert a TLS Local-Dynamic to a |
| // Local-Exec. |
| |
| inline void |
| Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo, |
| size_t relnum, |
| Output_segment*, |
| const elfcpp::Rel<32, false>& rel, |
| unsigned int, |
| elfcpp::Elf_types<32>::Elf_Addr, |
| unsigned char* view, |
| section_size_type view_size) |
| { |
| // leal foo(%reg), %eax; call ___tls_get_addr |
| // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi |
| |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9); |
| |
| // FIXME: Does this test really always pass? |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| view[-2] == 0x8d && view[-1] == 0x83); |
| |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8); |
| |
| memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11); |
| |
| // The next reloc should be a PLT32 reloc against __tls_get_addr. |
| // We can skip it. |
| this->skip_call_tls_get_addr_ = true; |
| } |
| |
| // Do a relocation in which we convert a TLS Initial-Exec to a |
| // Local-Exec. |
| |
| inline void |
| Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo, |
| size_t relnum, |
| Output_segment* tls_segment, |
| const elfcpp::Rel<32, false>& rel, |
| unsigned int r_type, |
| elfcpp::Elf_types<32>::Elf_Addr value, |
| unsigned char* view, |
| section_size_type view_size) |
| { |
| // We have to actually change the instructions, which means that we |
| // need to examine the opcodes to figure out which instruction we |
| // are looking at. |
| if (r_type == elfcpp::R_386_TLS_IE) |
| { |
| // movl %gs:XX,%eax ==> movl $YY,%eax |
| // movl %gs:XX,%reg ==> movl $YY,%reg |
| // addl %gs:XX,%reg ==> addl $YY,%reg |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1); |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4); |
| |
| unsigned char op1 = view[-1]; |
| if (op1 == 0xa1) |
| { |
| // movl XX,%eax ==> movl $YY,%eax |
| view[-1] = 0xb8; |
| } |
| else |
| { |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| |
| unsigned char op2 = view[-2]; |
| if (op2 == 0x8b) |
| { |
| // movl XX,%reg ==> movl $YY,%reg |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| (op1 & 0xc7) == 0x05); |
| view[-2] = 0xc7; |
| view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| } |
| else if (op2 == 0x03) |
| { |
| // addl XX,%reg ==> addl $YY,%reg |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| (op1 & 0xc7) == 0x05); |
| view[-2] = 0x81; |
| view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| } |
| else |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0); |
| } |
| } |
| else |
| { |
| // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2 |
| // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2 |
| // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2 |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4); |
| |
| unsigned char op1 = view[-1]; |
| unsigned char op2 = view[-2]; |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| (op1 & 0xc0) == 0x80 && (op1 & 7) != 4); |
| if (op2 == 0x8b) |
| { |
| // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2 |
| view[-2] = 0xc7; |
| view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| } |
| else if (op2 == 0x2b) |
| { |
| // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2 |
| view[-2] = 0x81; |
| view[-1] = 0xe8 | ((op1 >> 3) & 7); |
| } |
| else if (op2 == 0x03) |
| { |
| // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2 |
| view[-2] = 0x81; |
| view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| } |
| else |
| tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0); |
| } |
| |
| value = tls_segment->memsz() - value; |
| if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE) |
| value = - value; |
| |
| Relocate_functions<32, false>::rel32(view, value); |
| } |
| |
| // Relocate section data. |
| |
| void |
| Target_i386::relocate_section(const Relocate_info<32, false>* relinfo, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr address, |
| section_size_type view_size) |
| { |
| gold_assert(sh_type == elfcpp::SHT_REL); |
| |
| gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL, |
| Target_i386::Relocate>( |
| relinfo, |
| this, |
| prelocs, |
| reloc_count, |
| output_section, |
| needs_special_offset_handling, |
| view, |
| address, |
| view_size); |
| } |
| |
| // Return the size of a relocation while scanning during a relocatable |
| // link. |
| |
| unsigned int |
| Target_i386::Relocatable_size_for_reloc::get_size_for_reloc( |
| unsigned int r_type, |
| Relobj* object) |
| { |
| switch (r_type) |
| { |
| case elfcpp::R_386_NONE: |
| case elfcpp::R_386_GNU_VTINHERIT: |
| case elfcpp::R_386_GNU_VTENTRY: |
| case elfcpp::R_386_TLS_GD: // Global-dynamic |
| case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| case elfcpp::R_386_TLS_DESC_CALL: |
| case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| case elfcpp::R_386_TLS_IE: // Initial-exec |
| case elfcpp::R_386_TLS_IE_32: |
| case elfcpp::R_386_TLS_GOTIE: |
| case elfcpp::R_386_TLS_LE: // Local-exec |
| case elfcpp::R_386_TLS_LE_32: |
| return 0; |
| |
| case elfcpp::R_386_32: |
| case elfcpp::R_386_PC32: |
| case elfcpp::R_386_GOT32: |
| case elfcpp::R_386_PLT32: |
| case elfcpp::R_386_GOTOFF: |
| case elfcpp::R_386_GOTPC: |
| return 4; |
| |
| case elfcpp::R_386_16: |
| case elfcpp::R_386_PC16: |
| return 2; |
| |
| case elfcpp::R_386_8: |
| case elfcpp::R_386_PC8: |
| return 1; |
| |
| // These are relocations which should only be seen by the |
| // dynamic linker, and should never be seen here. |
| case elfcpp::R_386_COPY: |
| case elfcpp::R_386_GLOB_DAT: |
| case elfcpp::R_386_JUMP_SLOT: |
| case elfcpp::R_386_RELATIVE: |
| case elfcpp::R_386_TLS_TPOFF: |
| case elfcpp::R_386_TLS_DTPMOD32: |
| case elfcpp::R_386_TLS_DTPOFF32: |
| case elfcpp::R_386_TLS_TPOFF32: |
| case elfcpp::R_386_TLS_DESC: |
| object->error(_("unexpected reloc %u in object file"), r_type); |
| return 0; |
| |
| case elfcpp::R_386_32PLT: |
| case elfcpp::R_386_TLS_GD_32: |
| case elfcpp::R_386_TLS_GD_PUSH: |
| case elfcpp::R_386_TLS_GD_CALL: |
| case elfcpp::R_386_TLS_GD_POP: |
| case elfcpp::R_386_TLS_LDM_32: |
| case elfcpp::R_386_TLS_LDM_PUSH: |
| case elfcpp::R_386_TLS_LDM_CALL: |
| case elfcpp::R_386_TLS_LDM_POP: |
| case elfcpp::R_386_USED_BY_INTEL_200: |
| default: |
| object->error(_("unsupported reloc %u in object file"), r_type); |
| return 0; |
| } |
| } |
| |
| // Scan the relocs during a relocatable link. |
| |
| void |
| Target_i386::scan_relocatable_relocs(const General_options& options, |
| Symbol_table* symtab, |
| Layout* layout, |
| Sized_relobj<32, false>* object, |
| unsigned int data_shndx, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| bool needs_special_offset_handling, |
| size_t local_symbol_count, |
| const unsigned char* plocal_symbols, |
| Relocatable_relocs* rr) |
| { |
| gold_assert(sh_type == elfcpp::SHT_REL); |
| |
| typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL, |
| Relocatable_size_for_reloc> Scan_relocatable_relocs; |
| |
| gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL, |
| Scan_relocatable_relocs>( |
| options, |
| symtab, |
| layout, |
| object, |
| data_shndx, |
| prelocs, |
| reloc_count, |
| output_section, |
| needs_special_offset_handling, |
| local_symbol_count, |
| plocal_symbols, |
| rr); |
| } |
| |
| // Relocate a section during a relocatable link. |
| |
| void |
| Target_i386::relocate_for_relocatable( |
| const Relocate_info<32, false>* relinfo, |
| unsigned int sh_type, |
| const unsigned char* prelocs, |
| size_t reloc_count, |
| Output_section* output_section, |
| off_t offset_in_output_section, |
| const Relocatable_relocs* rr, |
| unsigned char* view, |
| elfcpp::Elf_types<32>::Elf_Addr view_address, |
| section_size_type view_size, |
| unsigned char* reloc_view, |
| section_size_type reloc_view_size) |
| { |
| gold_assert(sh_type == elfcpp::SHT_REL); |
| |
| gold::relocate_for_relocatable<32, false, 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 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. |
| |
| uint64_t |
| Target_i386::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(); |
| } |
| |
| // Return a string used to fill a code section with nops to take up |
| // the specified length. |
| |
| std::string |
| Target_i386::do_code_fill(section_size_type length) const |
| { |
| if (length >= 16) |
| { |
| // Build a jmp instruction to skip over the bytes. |
| unsigned char jmp[5]; |
| jmp[0] = 0xe9; |
| elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5); |
| return (std::string(reinterpret_cast<char*>(&jmp[0]), 5) |
| + std::string(length - 5, '\0')); |
| } |
| |
| // Nop sequences of various lengths. |
| const char nop1[1] = { 0x90 }; // nop |
| const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax |
| const char nop3[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi |
| const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi |
| const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26, // nop |
| 0x00 }; // leal 0(%esi,1),%esi |
| const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi |
| 0x00, 0x00 }; |
| const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi |
| 0x00, 0x00, 0x00 }; |
| const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop |
| 0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi |
| const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi |
| 0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi |
| 0x00 }; |
| const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi |
| 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi |
| 0x00, 0x00 }; |
| const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi |
| 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi |
| 0x00, 0x00, 0x00 }; |
| const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi |
| 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi |
| 0x00, 0x00, 0x00, 0x00 }; |
| const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi |
| 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi |
| 0x27, 0x00, 0x00, 0x00, |
| 0x00 }; |
| const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi |
| 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi |
| 0xbc, 0x27, 0x00, 0x00, |
| 0x00, 0x00 }; |
| const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15 |
| 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,... |
| 0x90, 0x90, 0x90, 0x90, |
| 0x90, 0x90, 0x90 }; |
| |
| const char* nops[16] = { |
| NULL, |
| nop1, nop2, nop3, nop4, nop5, nop6, nop7, |
| nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15 |
| }; |
| |
| return std::string(nops[length], length); |
| } |
| |
| // The selector for i386 object files. |
| |
| class Target_selector_i386 : public Target_selector |
| { |
| public: |
| Target_selector_i386() |
| : Target_selector(elfcpp::EM_386, 32, false, "elf32-i386") |
| { } |
| |
| Target* |
| do_instantiate_target() |
| { return new Target_i386(); } |
| }; |
| |
| Target_selector_i386 target_selector_i386; |
| |
| } // End anonymous namespace. |