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Diffstat (limited to 'binutils-2.25/gold/i386.cc')
| -rw-r--r-- | binutils-2.25/gold/i386.cc | 4168 |
1 files changed, 4168 insertions, 0 deletions
diff --git a/binutils-2.25/gold/i386.cc b/binutils-2.25/gold/i386.cc new file mode 100644 index 00000000..6a3280df --- /dev/null +++ b/binutils-2.25/gold/i386.cc @@ -0,0 +1,4168 @@ +// i386.cc -- i386 target support for gold. + +// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 +// 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 "dwarf.h" +#include "parameters.h" +#include "reloc.h" +#include "i386.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 "freebsd.h" +#include "nacl.h" +#include "gc.h" + +namespace +{ + +using namespace gold; + +// A class to handle the PLT data. +// This is an abstract base class that handles most of the linker details +// but does not know the actual contents of PLT entries. The derived +// classes below fill in those details. + +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*, uint64_t addralign, + Output_data_space*, Output_data_space*); + + // Add an entry to the PLT. + void + add_entry(Symbol_table*, Layout*, Symbol* gsym); + + // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. + unsigned int + add_local_ifunc_entry(Symbol_table*, Layout*, + Sized_relobj_file<32, false>* relobj, + unsigned int local_sym_index); + + // Return the .rel.plt section data. + Reloc_section* + rel_plt() const + { return this->rel_; } + + // Return where the TLS_DESC relocations should go. + Reloc_section* + rel_tls_desc(Layout*); + + // Return where the IRELATIVE relocations should go. + Reloc_section* + rel_irelative(Symbol_table*, Layout*); + + // Return whether we created a section for IRELATIVE relocations. + bool + has_irelative_section() const + { return this->irelative_rel_ != NULL; } + + // Return the number of PLT entries. + unsigned int + entry_count() const + { return this->count_ + this->irelative_count_; } + + // Return the offset of the first non-reserved PLT entry. + unsigned int + first_plt_entry_offset() + { return this->get_plt_entry_size(); } + + // Return the size of a PLT entry. + unsigned int + get_plt_entry_size() const + { return this->do_get_plt_entry_size(); } + + // Return the PLT address to use for a global symbol. + uint64_t + address_for_global(const Symbol*); + + // Return the PLT address to use for a local symbol. + uint64_t + address_for_local(const Relobj*, unsigned int symndx); + + // Add .eh_frame information for the PLT. + void + add_eh_frame(Layout* layout) + { this->do_add_eh_frame(layout); } + + protected: + // Fill the first PLT entry, given the pointer to the PLT section data + // and the runtime address of the GOT. + void + fill_first_plt_entry(unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr got_address) + { this->do_fill_first_plt_entry(pov, got_address); } + + // Fill a normal PLT entry, given the pointer to the entry's data in the + // section, the runtime address of the GOT, the offset into the GOT of + // the corresponding slot, the offset into the relocation section of the + // corresponding reloc, and the offset of this entry within the whole + // PLT. Return the offset from this PLT entry's runtime address that + // should be used to compute the initial value of the GOT slot. + unsigned int + fill_plt_entry(unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr got_address, + unsigned int got_offset, + unsigned int plt_offset, + unsigned int plt_rel_offset) + { + return this->do_fill_plt_entry(pov, got_address, got_offset, + plt_offset, plt_rel_offset); + } + + virtual unsigned int + do_get_plt_entry_size() const = 0; + + virtual void + do_fill_first_plt_entry(unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr got_address) = 0; + + virtual unsigned int + do_fill_plt_entry(unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr got_address, + unsigned int got_offset, + unsigned int plt_offset, + unsigned int plt_rel_offset) = 0; + + virtual void + do_add_eh_frame(Layout*) = 0; + + 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")); } + + // The .eh_frame unwind information for the PLT. + // The CIE is common across variants of the PLT format. + static const int plt_eh_frame_cie_size = 16; + static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size]; + + private: + // Set the final size. + void + set_final_data_size() + { + this->set_data_size((this->count_ + this->irelative_count_ + 1) + * this->get_plt_entry_size()); + } + + // Write out the PLT data. + void + do_write(Output_file*); + + // We keep a list of global STT_GNU_IFUNC symbols, each with its + // offset in the GOT. + struct Global_ifunc + { + Symbol* sym; + unsigned int got_offset; + }; + + // We keep a list of local STT_GNU_IFUNC symbols, each with its + // offset in the GOT. + struct Local_ifunc + { + Sized_relobj_file<32, false>* object; + unsigned int local_sym_index; + unsigned int got_offset; + }; + + // A pointer to the Layout class, so that we can find the .dynamic + // section when we write out the GOT PLT section. + Layout* layout_; + // The reloc section. + Reloc_section* rel_; + // The TLS_DESC relocations, if necessary. These must follow the + // regular PLT relocs. + Reloc_section* tls_desc_rel_; + // The IRELATIVE relocations, if necessary. These must follow the + // regular relocatoins and the TLS_DESC relocations. + Reloc_section* irelative_rel_; + // The .got.plt section. + Output_data_space* got_plt_; + // The part of the .got.plt section used for IRELATIVE relocs. + Output_data_space* got_irelative_; + // The number of PLT entries. + unsigned int count_; + // Number of PLT entries with R_386_IRELATIVE relocs. These follow + // the regular PLT entries. + unsigned int irelative_count_; + // Global STT_GNU_IFUNC symbols. + std::vector<Global_ifunc> global_ifuncs_; + // Local STT_GNU_IFUNC symbols. + std::vector<Local_ifunc> local_ifuncs_; +}; + +// This is an abstract class for the standard PLT layout. +// The derived classes below handle the actual PLT contents +// for the executable (non-PIC) and shared-library (PIC) cases. +// The unwind information is uniform across those two, so it's here. + +class Output_data_plt_i386_standard : public Output_data_plt_i386 +{ + public: + Output_data_plt_i386_standard(Layout* layout, + Output_data_space* got_plt, + Output_data_space* got_irelative) + : Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative) + { } + + protected: + virtual unsigned int + do_get_plt_entry_size() const + { return plt_entry_size; } + + virtual void + do_add_eh_frame(Layout* layout) + { + layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size, + plt_eh_frame_fde, plt_eh_frame_fde_size); + } + + // The size of an entry in the PLT. + static const int plt_entry_size = 16; + + // The .eh_frame unwind information for the PLT. + static const int plt_eh_frame_fde_size = 32; + static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size]; +}; + +// Actually fill the PLT contents for an executable (non-PIC). + +class Output_data_plt_i386_exec : public Output_data_plt_i386_standard +{ +public: + Output_data_plt_i386_exec(Layout* layout, + Output_data_space* got_plt, + Output_data_space* got_irelative) + : Output_data_plt_i386_standard(layout, got_plt, got_irelative) + { } + + protected: + virtual void + do_fill_first_plt_entry(unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr got_address); + + virtual unsigned int + do_fill_plt_entry(unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr got_address, + unsigned int got_offset, + unsigned int plt_offset, + unsigned int plt_rel_offset); + + private: + // The first entry in the PLT for an executable. + static const unsigned char first_plt_entry[plt_entry_size]; + + // Other entries in the PLT for an executable. + static const unsigned char plt_entry[plt_entry_size]; +}; + +// Actually fill the PLT contents for a shared library (PIC). + +class Output_data_plt_i386_dyn : public Output_data_plt_i386_standard +{ + public: + Output_data_plt_i386_dyn(Layout* layout, + Output_data_space* got_plt, + Output_data_space* got_irelative) + : Output_data_plt_i386_standard(layout, got_plt, got_irelative) + { } + + protected: + virtual void + do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr); + + virtual unsigned int + do_fill_plt_entry(unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr, + unsigned int got_offset, + unsigned int plt_offset, + unsigned int plt_rel_offset); + + private: + // The first entry in the PLT for a shared object. + static const unsigned char first_plt_entry[plt_entry_size]; + + // Other entries in the PLT for a shared object. + static const unsigned char plt_entry[plt_entry_size]; +}; + +// 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(const Target::Target_info* info = &i386_info) + : Sized_target<32, false>(info), + got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL), + got_tlsdesc_(NULL), global_offset_table_(NULL), rel_dyn_(NULL), + rel_irelative_(NULL), copy_relocs_(elfcpp::R_386_COPY), + got_mod_index_offset_(-1U), tls_base_symbol_defined_(false) + { } + + // Process the relocations to determine unreferenced sections for + // garbage collection. + void + gc_process_relocs(Symbol_table* symtab, + Layout* layout, + Sized_relobj_file<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); + + // Scan the relocations to look for symbol adjustments. + void + scan_relocs(Symbol_table* symtab, + Layout* layout, + Sized_relobj_file<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*, const Input_objects*, Symbol_table*); + + // 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, + const Reloc_symbol_changes*); + + // Scan the relocs during a relocatable link. + void + scan_relocatable_relocs(Symbol_table* symtab, + Layout* layout, + Sized_relobj_file<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*); + + // Emit relocations for a section. + void + relocate_relocs(const Relocate_info<32, false>*, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + elfcpp::Elf_types<32>::Elf_Off 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(const Symbol* sym) const + { return strcmp(sym->name(), "___tls_get_addr") == 0; } + + // Return whether a symbol name implies a local label. The UnixWare + // 2.1 cc generates temporary symbols that start with .X, so we + // recognize them here. FIXME: do other SVR4 compilers also use .X?. + // If so, we should move the .X recognition into + // Target::do_is_local_label_name. + bool + do_is_local_label_name(const char* name) const + { + if (name[0] == '.' && name[1] == 'X') + return true; + return Target::do_is_local_label_name(name); + } + + // Return the PLT address to use for a global symbol. + uint64_t + do_plt_address_for_global(const Symbol* gsym) const + { return this->plt_section()->address_for_global(gsym); } + + uint64_t + do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const + { return this->plt_section()->address_for_local(relobj, symndx); } + + // We can tell whether we take the address of a function. + inline bool + do_can_check_for_function_pointers() const + { return true; } + + // Return the base for a DW_EH_PE_datarel encoding. + uint64_t + do_ehframe_datarel_base() const; + + // Return whether SYM is call to a non-split function. + bool + do_is_call_to_non_split(const Symbol* sym, unsigned int) const; + + // Adjust -fsplit-stack code which calls non-split-stack code. + void + do_calls_non_split(Relobj* object, unsigned int shndx, + section_offset_type fnoffset, section_size_type fnsize, + unsigned char* view, section_size_type view_size, + std::string* from, std::string* to) const; + + // Return the size of the GOT section. + section_size_type + got_size() const + { + gold_assert(this->got_ != NULL); + return this->got_->data_size(); + } + + // Return the number of entries in the GOT. + unsigned int + got_entry_count() const + { + if (this->got_ == NULL) + return 0; + return this->got_size() / 4; + } + + // Return the number of entries in the PLT. + unsigned int + plt_entry_count() const; + + // Return the offset of the first non-reserved PLT entry. + unsigned int + first_plt_entry_offset() const; + + // Return the size of each PLT entry. + unsigned int + plt_entry_size() const; + + protected: + // Instantiate the plt_ member. + // This chooses the right PLT flavor for an executable or a shared object. + Output_data_plt_i386* + make_data_plt(Layout* layout, + Output_data_space* got_plt, + Output_data_space* got_irelative, + bool dyn) + { return this->do_make_data_plt(layout, got_plt, got_irelative, dyn); } + + virtual Output_data_plt_i386* + do_make_data_plt(Layout* layout, + Output_data_space* got_plt, + Output_data_space* got_irelative, + bool dyn) + { + if (dyn) + return new Output_data_plt_i386_dyn(layout, got_plt, got_irelative); + else + return new Output_data_plt_i386_exec(layout, got_plt, got_irelative); + } + + private: + // The class which scans relocations. + struct Scan + { + static inline int + + get_reference_flags(unsigned int r_type); + + inline void + local(Symbol_table* symtab, Layout* layout, Target_i386* target, + Sized_relobj_file<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, + bool is_discarded); + + inline void + global(Symbol_table* symtab, Layout* layout, Target_i386* target, + Sized_relobj_file<32, false>* object, + unsigned int data_shndx, + Output_section* output_section, + const elfcpp::Rel<32, false>& reloc, unsigned int r_type, + Symbol* gsym); + + inline bool + local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, + Target_i386* target, + Sized_relobj_file<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 bool + global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, + Target_i386* target, + Sized_relobj_file<32, false>* object, + unsigned int data_shndx, + Output_section* output_section, + const elfcpp::Rel<32, false>& reloc, + unsigned int r_type, + Symbol* gsym); + + inline bool + possible_function_pointer_reloc(unsigned int r_type); + + bool + reloc_needs_plt_for_ifunc(Sized_relobj_file<32, false>*, + unsigned int r_type); + + static void + unsupported_reloc_local(Sized_relobj_file<32, false>*, unsigned int r_type); + + static void + unsupported_reloc_global(Sized_relobj_file<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, + unsigned int r_type, + 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, false>*, Target_i386*, Output_section*, + 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_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec + // transition. + inline void + tls_desc_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_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec + // transition. + inline void + tls_desc_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_; + } + + // Get the GOT section for TLSDESC entries. + Output_data_got<32, false>* + got_tlsdesc_section() const + { + gold_assert(this->got_tlsdesc_ != NULL); + return this->got_tlsdesc_; + } + + // Create the PLT section. + void + make_plt_section(Symbol_table* symtab, Layout* layout); + + // Create a PLT entry for a global symbol. + void + make_plt_entry(Symbol_table*, Layout*, Symbol*); + + // Create a PLT entry for a local STT_GNU_IFUNC symbol. + void + make_local_ifunc_plt_entry(Symbol_table*, Layout*, + Sized_relobj_file<32, false>* relobj, + unsigned int local_sym_index); + + // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. + void + define_tls_base_symbol(Symbol_table*, Layout*); + + // Create a GOT entry for the TLS module index. + unsigned int + got_mod_index_entry(Symbol_table* symtab, Layout* layout, + Sized_relobj_file<32, false>* object); + + // Get the PLT section. + 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*); + + // Get the section to use for TLS_DESC relocations. + Reloc_section* + rel_tls_desc_section(Layout*) const; + + // Get the section to use for IRELATIVE relocations. + Reloc_section* + rel_irelative_section(Layout*); + + // Add a potential copy relocation. + void + copy_reloc(Symbol_table* symtab, Layout* layout, + Sized_relobj_file<32, false>* object, + unsigned int shndx, Output_section* output_section, + Symbol* sym, const elfcpp::Rel<32, false>& reloc) + { + this->copy_relocs_.copy_reloc(symtab, layout, + symtab->get_sized_symbol<32>(sym), + object, shndx, output_section, reloc, + this->rel_dyn_section(layout)); + } + + // Information about this specific target which we pass to the + // general Target structure. + static const Target::Target_info i386_info; + + // The types of GOT entries needed for this platform. + // These values are exposed to the ABI in an incremental link. + // Do not renumber existing values without changing the version + // number of the .gnu_incremental_inputs section. + enum Got_type + { + GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol + GOT_TYPE_TLS_NOFFSET = 1, // GOT entry for negative TLS offset + GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset + GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair + GOT_TYPE_TLS_DESC = 4 // 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 GOT section for IRELATIVE relocations. + Output_data_space* got_irelative_; + // The GOT section for TLSDESC relocations. + Output_data_got<32, false>* got_tlsdesc_; + // The _GLOBAL_OFFSET_TABLE_ symbol. + Symbol* global_offset_table_; + // The dynamic reloc section. + Reloc_section* rel_dyn_; + // The section to use for IRELATIVE relocs. + Reloc_section* rel_irelative_; + // Relocs saved to avoid a COPY reloc. + Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_; + // Offset of the GOT entry for the TLS module index. + unsigned int got_mod_index_offset_; + // True if the _TLS_MODULE_BASE_ symbol has been defined. + bool tls_base_symbol_defined_; +}; + +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 + true, // can_icf_inline_merge_sections + '\0', // wrap_char + "/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) + false, // isolate_execinstr + 0, // rosegment_gap + elfcpp::SHN_UNDEF, // small_common_shndx + elfcpp::SHN_UNDEF, // large_common_shndx + 0, // small_common_section_flags + 0, // large_common_section_flags + NULL, // attributes_section + NULL, // attributes_vendor + "_start" // entry_symbol_name +}; + +// 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>(); + + // When using -z now, we can treat .got.plt as a relro section. + // Without -z now, it is modified after program startup by lazy + // PLT relocations. + bool is_got_plt_relro = parameters->options().now(); + Output_section_order got_order = (is_got_plt_relro + ? ORDER_RELRO + : ORDER_RELRO_LAST); + Output_section_order got_plt_order = (is_got_plt_relro + ? ORDER_RELRO + : ORDER_NON_RELRO_FIRST); + + layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_WRITE), + this->got_, got_order, true); + + this->got_plt_ = new Output_data_space(4, "** GOT PLT"); + layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_WRITE), + this->got_plt_, got_plt_order, + is_got_plt_relro); + + // The first three entries are reserved. + this->got_plt_->set_current_data_size(3 * 4); + + if (!is_got_plt_relro) + { + // Those bytes can go into the relro segment. + layout->increase_relro(3 * 4); + } + + // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. + this->global_offset_table_ = + symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, + Symbol_table::PREDEFINED, + this->got_plt_, + 0, 0, elfcpp::STT_OBJECT, + elfcpp::STB_LOCAL, + elfcpp::STV_HIDDEN, 0, + false, false); + + // If there are any IRELATIVE relocations, they get GOT entries + // in .got.plt after the jump slot relocations. + this->got_irelative_ = new Output_data_space(4, "** GOT IRELATIVE PLT"); + layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_WRITE), + this->got_irelative_, + got_plt_order, is_got_plt_relro); + + // If there are any TLSDESC relocations, they get GOT entries in + // .got.plt after the jump slot entries. + this->got_tlsdesc_ = new Output_data_got<32, false>(); + layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_WRITE), + this->got_tlsdesc_, + got_plt_order, is_got_plt_relro); + } + + 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(parameters->options().combreloc()); + layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL, + elfcpp::SHF_ALLOC, this->rel_dyn_, + ORDER_DYNAMIC_RELOCS, false); + } + return this->rel_dyn_; +} + +// Get the section to use for IRELATIVE relocs, creating it if +// necessary. These go in .rel.dyn, but only after all other dynamic +// relocations. They need to follow the other dynamic relocations so +// that they can refer to global variables initialized by those +// relocs. + +Target_i386::Reloc_section* +Target_i386::rel_irelative_section(Layout* layout) +{ + if (this->rel_irelative_ == NULL) + { + // Make sure we have already create the dynamic reloc section. + this->rel_dyn_section(layout); + this->rel_irelative_ = new Reloc_section(false); + layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL, + elfcpp::SHF_ALLOC, this->rel_irelative_, + ORDER_DYNAMIC_RELOCS, false); + gold_assert(this->rel_dyn_->output_section() + == this->rel_irelative_->output_section()); + } + return this->rel_irelative_; +} + +// 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, + uint64_t addralign, + Output_data_space* got_plt, + Output_data_space* got_irelative) + : Output_section_data(addralign), + layout_(layout), tls_desc_rel_(NULL), + irelative_rel_(NULL), got_plt_(got_plt), got_irelative_(got_irelative), + count_(0), irelative_count_(0), global_ifuncs_(), local_ifuncs_() +{ + this->rel_ = new Reloc_section(false); + layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, + elfcpp::SHF_ALLOC, this->rel_, + ORDER_DYNAMIC_PLT_RELOCS, false); +} + +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_table* symtab, Layout* layout, + Symbol* gsym) +{ + gold_assert(!gsym->has_plt_offset()); + + // Every PLT entry needs a reloc. + if (gsym->type() == elfcpp::STT_GNU_IFUNC + && gsym->can_use_relative_reloc(false)) + { + gsym->set_plt_offset(this->irelative_count_ * this->get_plt_entry_size()); + ++this->irelative_count_; + section_offset_type got_offset = + this->got_irelative_->current_data_size(); + this->got_irelative_->set_current_data_size(got_offset + 4); + Reloc_section* rel = this->rel_irelative(symtab, layout); + rel->add_symbolless_global_addend(gsym, elfcpp::R_386_IRELATIVE, + this->got_irelative_, got_offset); + struct Global_ifunc gi; + gi.sym = gsym; + gi.got_offset = got_offset; + this->global_ifuncs_.push_back(gi); + } + else + { + // When setting the PLT offset we skip the initial reserved PLT + // entry. + gsym->set_plt_offset((this->count_ + 1) * this->get_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); + + 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. +} + +// Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return +// the PLT offset. + +unsigned int +Output_data_plt_i386::add_local_ifunc_entry( + Symbol_table* symtab, + Layout* layout, + Sized_relobj_file<32, false>* relobj, + unsigned int local_sym_index) +{ + unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size(); + ++this->irelative_count_; + + section_offset_type got_offset = this->got_irelative_->current_data_size(); + + // Every PLT entry needs a GOT entry which points back to the PLT + // entry. + this->got_irelative_->set_current_data_size(got_offset + 4); + + // Every PLT entry needs a reloc. + Reloc_section* rel = this->rel_irelative(symtab, layout); + rel->add_symbolless_local_addend(relobj, local_sym_index, + elfcpp::R_386_IRELATIVE, + this->got_irelative_, got_offset); + + struct Local_ifunc li; + li.object = relobj; + li.local_sym_index = local_sym_index; + li.got_offset = got_offset; + this->local_ifuncs_.push_back(li); + + return plt_offset; +} + +// Return where the TLS_DESC relocations should go, creating it if +// necessary. These follow the JUMP_SLOT relocations. + +Output_data_plt_i386::Reloc_section* +Output_data_plt_i386::rel_tls_desc(Layout* layout) +{ + if (this->tls_desc_rel_ == NULL) + { + this->tls_desc_rel_ = new Reloc_section(false); + layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, + elfcpp::SHF_ALLOC, this->tls_desc_rel_, + ORDER_DYNAMIC_PLT_RELOCS, false); + gold_assert(this->tls_desc_rel_->output_section() + == this->rel_->output_section()); + } + return this->tls_desc_rel_; +} + +// Return where the IRELATIVE relocations should go in the PLT. These +// follow the JUMP_SLOT and TLS_DESC relocations. + +Output_data_plt_i386::Reloc_section* +Output_data_plt_i386::rel_irelative(Symbol_table* symtab, Layout* layout) +{ + if (this->irelative_rel_ == NULL) + { + // Make sure we have a place for the TLS_DESC relocations, in + // case we see any later on. + this->rel_tls_desc(layout); + this->irelative_rel_ = new Reloc_section(false); + layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, + elfcpp::SHF_ALLOC, this->irelative_rel_, + ORDER_DYNAMIC_PLT_RELOCS, false); + gold_assert(this->irelative_rel_->output_section() + == this->rel_->output_section()); + + if (parameters->doing_static_link()) + { + // A statically linked executable will only have a .rel.plt + // section to hold R_386_IRELATIVE relocs for STT_GNU_IFUNC + // symbols. The library will use these symbols to locate + // the IRELATIVE relocs at program startup time. + symtab->define_in_output_data("__rel_iplt_start", NULL, + Symbol_table::PREDEFINED, + this->irelative_rel_, 0, 0, + elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, + elfcpp::STV_HIDDEN, 0, false, true); + symtab->define_in_output_data("__rel_iplt_end", NULL, + Symbol_table::PREDEFINED, + this->irelative_rel_, 0, 0, + elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, + elfcpp::STV_HIDDEN, 0, true, true); + } + } + return this->irelative_rel_; +} + +// Return the PLT address to use for a global symbol. + +uint64_t +Output_data_plt_i386::address_for_global(const Symbol* gsym) +{ + uint64_t offset = 0; + if (gsym->type() == elfcpp::STT_GNU_IFUNC + && gsym->can_use_relative_reloc(false)) + offset = (this->count_ + 1) * this->get_plt_entry_size(); + return this->address() + offset + gsym->plt_offset(); +} + +// Return the PLT address to use for a local symbol. These are always +// IRELATIVE relocs. + +uint64_t +Output_data_plt_i386::address_for_local(const Relobj* object, + unsigned int r_sym) +{ + return (this->address() + + (this->count_ + 1) * this->get_plt_entry_size() + + object->local_plt_offset(r_sym)); +} + +// The first entry in the PLT for an executable. + +const 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 +}; + +void +Output_data_plt_i386_exec::do_fill_first_plt_entry( + unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr got_address) +{ + memcpy(pov, 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); +} + +// The first entry in the PLT for a shared object. + +const 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 +}; + +void +Output_data_plt_i386_dyn::do_fill_first_plt_entry( + unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr) +{ + memcpy(pov, first_plt_entry, plt_entry_size); +} + +// Subsequent entries in the PLT for an executable. + +const 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 +}; + +unsigned int +Output_data_plt_i386_exec::do_fill_plt_entry( + unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr got_address, + unsigned int got_offset, + unsigned int plt_offset, + unsigned int plt_rel_offset) +{ + memcpy(pov, 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 + 12 + 4)); + return 6; +} + +// Subsequent entries in the PLT for a shared object. + +const 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 +}; + +unsigned int +Output_data_plt_i386_dyn::do_fill_plt_entry(unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr, + unsigned int got_offset, + unsigned int plt_offset, + unsigned int plt_rel_offset) +{ + memcpy(pov, plt_entry, plt_entry_size); + elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset); + elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset); + elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4)); + return 6; +} + +// The .eh_frame unwind information for the PLT. + +const unsigned char +Output_data_plt_i386::plt_eh_frame_cie[plt_eh_frame_cie_size] = +{ + 1, // CIE version. + 'z', // Augmentation: augmentation size included. + 'R', // Augmentation: FDE encoding included. + '\0', // End of augmentation string. + 1, // Code alignment factor. + 0x7c, // Data alignment factor. + 8, // Return address column. + 1, // Augmentation size. + (elfcpp::DW_EH_PE_pcrel // FDE encoding. + | elfcpp::DW_EH_PE_sdata4), + elfcpp::DW_CFA_def_cfa, 4, 4, // DW_CFA_def_cfa: r4 (esp) ofs 4. + elfcpp::DW_CFA_offset + 8, 1, // DW_CFA_offset: r8 (eip) at cfa-4. + elfcpp::DW_CFA_nop, // Align to 16 bytes. + elfcpp::DW_CFA_nop +}; + +const unsigned char +Output_data_plt_i386_standard::plt_eh_frame_fde[plt_eh_frame_fde_size] = +{ + 0, 0, 0, 0, // Replaced with offset to .plt. + 0, 0, 0, 0, // Replaced with size of .plt. + 0, // Augmentation size. + elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8. + elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6. + elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12. + elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16. + elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression. + 11, // Block length. + elfcpp::DW_OP_breg4, 4, // Push %esp + 4. + elfcpp::DW_OP_breg8, 0, // Push %eip. + elfcpp::DW_OP_lit15, // Push 0xf. + elfcpp::DW_OP_and, // & (%eip & 0xf). + elfcpp::DW_OP_lit11, // Push 0xb. + elfcpp::DW_OP_ge, // >= ((%eip & 0xf) >= 0xb) + elfcpp::DW_OP_lit2, // Push 2. + elfcpp::DW_OP_shl, // << (((%eip & 0xf) >= 0xb) << 2) + elfcpp::DW_OP_plus, // + ((((%eip&0xf)>=0xb)<<2)+%esp+4 + elfcpp::DW_CFA_nop, // Align to 32 bytes. + elfcpp::DW_CFA_nop, + elfcpp::DW_CFA_nop, + elfcpp::DW_CFA_nop +}; + +// 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(); + gold_assert(parameters->incremental_update() + || (got_file_offset + this->got_plt_->data_size() + == this->got_irelative_->offset())); + const section_size_type got_size = + convert_to_section_size_type(this->got_plt_->data_size() + + this->got_irelative_->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(); + + this->fill_first_plt_entry(pov, got_address); + pov += this->get_plt_entry_size(); + + unsigned char* got_pov = got_view; + + // The first entry in the GOT is the address of the .dynamic section + // aka the PT_DYNAMIC segment. The next two entries are reserved. + // We saved space for them when we created the section in + // Target_i386::got_section. + Output_section* dynamic = this->layout_->dynamic_section(); + uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address(); + elfcpp::Swap<32, false>::writeval(got_pov, dynamic_addr); + got_pov += 4; + memset(got_pov, 0, 8); + got_pov += 8; + + const int rel_size = elfcpp::Elf_sizes<32>::rel_size; + + unsigned int plt_offset = this->get_plt_entry_size(); + unsigned int plt_rel_offset = 0; + unsigned int got_offset = 12; + const unsigned int count = this->count_ + this->irelative_count_; + for (unsigned int i = 0; + i < count; + ++i, + pov += this->get_plt_entry_size(), + got_pov += 4, + plt_offset += this->get_plt_entry_size(), + plt_rel_offset += rel_size, + got_offset += 4) + { + // Set and adjust the PLT entry itself. + unsigned int lazy_offset = this->fill_plt_entry(pov, + got_address, + got_offset, + plt_offset, + plt_rel_offset); + + // Set the entry in the GOT. + elfcpp::Swap<32, false>::writeval(got_pov, + plt_address + plt_offset + lazy_offset); + } + + // If any STT_GNU_IFUNC symbols have PLT entries, we need to change + // the GOT to point to the actual symbol value, rather than point to + // the PLT entry. That will let the dynamic linker call the right + // function when resolving IRELATIVE relocations. + unsigned char* got_irelative_view = got_view + this->got_plt_->data_size(); + for (std::vector<Global_ifunc>::const_iterator p = + this->global_ifuncs_.begin(); + p != this->global_ifuncs_.end(); + ++p) + { + const Sized_symbol<32>* ssym = + static_cast<const Sized_symbol<32>*>(p->sym); + elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset, + ssym->value()); + } + + for (std::vector<Local_ifunc>::const_iterator p = + this->local_ifuncs_.begin(); + p != this->local_ifuncs_.end(); + ++p) + { + const Symbol_value<32>* psymval = + p->object->local_symbol(p->local_sym_index); + elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset, + psymval->value(p->object, 0)); + } + + 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 the PLT section. + +void +Target_i386::make_plt_section(Symbol_table* symtab, Layout* layout) +{ + if (this->plt_ == NULL) + { + // Create the GOT sections first. + this->got_section(symtab, layout); + + const bool dyn = parameters->options().output_is_position_independent(); + this->plt_ = this->make_data_plt(layout, + this->got_plt_, + this->got_irelative_, + dyn); + + // Add unwind information if requested. + if (parameters->options().ld_generated_unwind_info()) + this->plt_->add_eh_frame(layout); + + layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_EXECINSTR), + this->plt_, ORDER_PLT, false); + + // Make the sh_info field of .rel.plt point to .plt. + Output_section* rel_plt_os = this->plt_->rel_plt()->output_section(); + rel_plt_os->set_info_section(this->plt_->output_section()); + } +} + +// 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) + this->make_plt_section(symtab, layout); + this->plt_->add_entry(symtab, layout, gsym); +} + +// Make a PLT entry for a local STT_GNU_IFUNC symbol. + +void +Target_i386::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout, + Sized_relobj_file<32, false>* relobj, + unsigned int local_sym_index) +{ + if (relobj->local_has_plt_offset(local_sym_index)) + return; + if (this->plt_ == NULL) + this->make_plt_section(symtab, layout); + unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout, + relobj, + local_sym_index); + relobj->set_local_plt_offset(local_sym_index, plt_offset); +} + +// Return the number of entries in the PLT. + +unsigned int +Target_i386::plt_entry_count() const +{ + if (this->plt_ == NULL) + return 0; + return this->plt_->entry_count(); +} + +// Return the offset of the first non-reserved PLT entry. + +unsigned int +Target_i386::first_plt_entry_offset() const +{ + return this->plt_->first_plt_entry_offset(); +} + +// Return the size of each PLT entry. + +unsigned int +Target_i386::plt_entry_size() const +{ + return this->plt_->get_plt_entry_size(); +} + +// Get the section to use for TLS_DESC relocations. + +Target_i386::Reloc_section* +Target_i386::rel_tls_desc_section(Layout* layout) const +{ + return this->plt_section()->rel_tls_desc(layout); +} + +// Define the _TLS_MODULE_BASE_ symbol in the TLS segment. + +void +Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout) +{ + if (this->tls_base_symbol_defined_) + return; + + Output_segment* tls_segment = layout->tls_segment(); + if (tls_segment != NULL) + { + bool is_exec = parameters->options().output_is_executable(); + symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL, + Symbol_table::PREDEFINED, + tls_segment, 0, 0, + elfcpp::STT_TLS, + elfcpp::STB_LOCAL, + elfcpp::STV_HIDDEN, 0, + (is_exec + ? Symbol::SEGMENT_END + : Symbol::SEGMENT_START), + true); + } + this->tls_base_symbol_defined_ = true; +} + +// Create a GOT entry for the TLS module index. + +unsigned int +Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout, + Sized_relobj_file<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_; +} + +// 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(); + } +} + +// Get the Reference_flags for a particular relocation. + +int +Target_i386::Scan::get_reference_flags(unsigned int r_type) +{ + switch (r_type) + { + case elfcpp::R_386_NONE: + case elfcpp::R_386_GNU_VTINHERIT: + case elfcpp::R_386_GNU_VTENTRY: + case elfcpp::R_386_GOTPC: + // No symbol reference. + return 0; + + case elfcpp::R_386_32: + case elfcpp::R_386_16: + case elfcpp::R_386_8: + return Symbol::ABSOLUTE_REF; + + case elfcpp::R_386_PC32: + case elfcpp::R_386_PC16: + case elfcpp::R_386_PC8: + case elfcpp::R_386_GOTOFF: + return Symbol::RELATIVE_REF; + + case elfcpp::R_386_PLT32: + return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF; + + case elfcpp::R_386_GOT32: + // Absolute in GOT. + return Symbol::ABSOLUTE_REF; + + 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 Symbol::TLS_REF; + + 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_IRELATIVE: + 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: + 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: + // Not expected. We will give an error later. + return 0; + } +} + +// Report an unsupported relocation against a local symbol. + +void +Target_i386::Scan::unsupported_reloc_local(Sized_relobj_file<32, false>* object, + unsigned int r_type) +{ + gold_error(_("%s: unsupported reloc %u against local symbol"), + object->name().c_str(), r_type); +} + +// Return whether we need to make a PLT entry for a relocation of a +// given type against a STT_GNU_IFUNC symbol. + +bool +Target_i386::Scan::reloc_needs_plt_for_ifunc( + Sized_relobj_file<32, false>* object, + unsigned int r_type) +{ + int flags = Scan::get_reference_flags(r_type); + if (flags & Symbol::TLS_REF) + gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"), + object->name().c_str(), r_type); + return flags != 0; +} + +// Scan a relocation for a local symbol. + +inline void +Target_i386::Scan::local(Symbol_table* symtab, + Layout* layout, + Target_i386* target, + Sized_relobj_file<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, + bool is_discarded) +{ + if (is_discarded) + return; + + // A local STT_GNU_IFUNC symbol may require a PLT entry. + if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC + && this->reloc_needs_plt_for_ifunc(object, r_type)) + { + unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); + target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym); + } + + 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); + unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); + if (lsym.get_st_type() != elfcpp::STT_SECTION) + 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); + unsigned int shndx = lsym.get_st_shndx(); + bool is_ordinary; + shndx = object->adjust_sym_shndx(r_sym, shndx, + &is_ordinary); + if (!is_ordinary) + object->error(_("section symbol %u has bad shndx %u"), + r_sym, shndx); + else + rel_dyn->add_local_section(object, 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()); + + // For a STT_GNU_IFUNC symbol we want the PLT offset. That + // lets function pointers compare correctly with shared + // libraries. Otherwise we would need an IRELATIVE reloc. + bool is_new; + if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC) + is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD); + else + is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD); + if (is_new) + { + // 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 got_offset = + object->local_got_offset(r_sym, GOT_TYPE_STANDARD); + rel_dyn->add_local_relative(object, r_sym, + elfcpp::R_386_RELATIVE, + got, got_offset); + } + } + } + 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_IRELATIVE: + 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()); + unsigned int shndx = lsym.get_st_shndx(); + bool is_ordinary; + shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); + if (!is_ordinary) + object->error(_("local symbol %u has bad shndx %u"), + r_sym, shndx); + else + got->add_local_pair_with_rel(object, r_sym, shndx, + GOT_TYPE_TLS_PAIR, + target->rel_dyn_section(layout), + elfcpp::R_386_TLS_DTPMOD32); + } + 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) + target->define_tls_base_symbol(symtab, layout); + if (optimized_type == tls::TLSOPT_NONE) + { + // Create a double GOT entry with an R_386_TLS_DESC + // reloc. The R_386_TLS_DESC reloc is resolved + // lazily, so the GOT entry needs to be in an area in + // .got.plt, not .got. Call got_section to make sure + // the section has been created. + target->got_section(symtab, layout); + Output_data_got<32, false>* got = target->got_tlsdesc_section(); + unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); + if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC)) + { + unsigned int got_offset = got->add_constant(0); + // The local symbol value is stored in the second + // GOT entry. + got->add_local(object, r_sym, GOT_TYPE_TLS_DESC); + // That set the GOT offset of the local symbol to + // point to the second entry, but we want it to + // point to the first. + object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC, + got_offset); + Reloc_section* rt = target->rel_tls_desc_section(layout); + rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset); + } + } + else if (optimized_type != tls::TLSOPT_TO_LE) + unsupported_reloc_local(object, r_type); + break; + + case elfcpp::R_386_TLS_DESC_CALL: + 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); + unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32 + ? GOT_TYPE_TLS_OFFSET + : GOT_TYPE_TLS_NOFFSET); + got->add_local_with_rel(object, r_sym, got_type, + 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_file<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()); +} + +inline bool +Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type) +{ + switch (r_type) + { + case elfcpp::R_386_32: + case elfcpp::R_386_16: + case elfcpp::R_386_8: + case elfcpp::R_386_GOTOFF: + case elfcpp::R_386_GOT32: + { + return true; + } + default: + return false; + } + return false; +} + +inline bool +Target_i386::Scan::local_reloc_may_be_function_pointer( + Symbol_table* , + Layout* , + Target_i386* , + Sized_relobj_file<32, false>* , + unsigned int , + Output_section* , + const elfcpp::Rel<32, false>& , + unsigned int r_type, + const elfcpp::Sym<32, false>&) +{ + return possible_function_pointer_reloc(r_type); +} + +inline bool +Target_i386::Scan::global_reloc_may_be_function_pointer( + Symbol_table* , + Layout* , + Target_i386* , + Sized_relobj_file<32, false>* , + unsigned int , + Output_section* , + const elfcpp::Rel<32, false>& , + unsigned int r_type, + Symbol*) +{ + return possible_function_pointer_reloc(r_type); +} + +// Scan a relocation for a global symbol. + +inline void +Target_i386::Scan::global(Symbol_table* symtab, + Layout* layout, + Target_i386* target, + Sized_relobj_file<32, false>* object, + unsigned int data_shndx, + Output_section* output_section, + const elfcpp::Rel<32, false>& reloc, + unsigned int r_type, + Symbol* gsym) +{ + // A STT_GNU_IFUNC symbol may require a PLT entry. + if (gsym->type() == elfcpp::STT_GNU_IFUNC + && this->reloc_needs_plt_for_ifunc(object, r_type)) + target->make_plt_entry(symtab, layout, 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(Scan::get_reference_flags(r_type))) + { + if (gsym->may_need_copy_reloc()) + { + target->copy_reloc(symtab, layout, object, + data_shndx, output_section, gsym, reloc); + } + else if (r_type == elfcpp::R_386_32 + && gsym->type() == elfcpp::STT_GNU_IFUNC + && gsym->can_use_relative_reloc(false) + && !gsym->is_from_dynobj() + && !gsym->is_undefined() + && !gsym->is_preemptible()) + { + // Use an IRELATIVE reloc for a locally defined + // STT_GNU_IFUNC symbol. This makes a function + // address in a PIE executable match the address in a + // shared library that it links against. + Reloc_section* rel_dyn = target->rel_irelative_section(layout); + rel_dyn->add_symbolless_global_addend(gsym, + elfcpp::R_386_IRELATIVE, + output_section, + object, data_shndx, + reloc.get_r_offset()); + } + 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. + if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))) + { + if (gsym->may_need_copy_reloc()) + { + target->copy_reloc(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()) + { + // For a STT_GNU_IFUNC symbol we want the PLT address. + if (gsym->type() == elfcpp::STT_GNU_IFUNC) + got->add_global_plt(gsym, GOT_TYPE_STANDARD); + else + 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); + + // Use a GLOB_DAT rather than a RELATIVE reloc if: + // + // 1) The symbol may be defined in some other module. + // + // 2) We are building a shared library and this is a + // protected symbol; using GLOB_DAT means that the dynamic + // linker can use the address of the PLT in the main + // executable when appropriate so that function address + // comparisons work. + // + // 3) This is a STT_GNU_IFUNC symbol in position dependent + // code, again so that function address comparisons work. + if (gsym->is_from_dynobj() + || gsym->is_undefined() + || gsym->is_preemptible() + || (gsym->visibility() == elfcpp::STV_PROTECTED + && parameters->options().shared()) + || (gsym->type() == elfcpp::STT_GNU_IFUNC + && parameters->options().output_is_position_independent())) + got->add_global_with_rel(gsym, GOT_TYPE_STANDARD, + rel_dyn, elfcpp::R_386_GLOB_DAT); + else + { + // For a STT_GNU_IFUNC symbol we want to write the PLT + // offset into the GOT, so that function pointer + // comparisons work correctly. + bool is_new; + if (gsym->type() != elfcpp::STT_GNU_IFUNC) + is_new = got->add_global(gsym, GOT_TYPE_STANDARD); + else + { + is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD); + // Tell the dynamic linker to use the PLT address + // when resolving relocations. + if (gsym->is_from_dynobj() + && !parameters->options().shared()) + gsym->set_needs_dynsym_value(); + } + if (is_new) + { + unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD); + rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE, + got, got_off); + } + } + } + } + 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_IRELATIVE: + 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_NOFFSET, + target->rel_dyn_section(layout), + elfcpp::R_386_TLS_TPOFF); + } + 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) + target->define_tls_base_symbol(symtab, layout); + if (optimized_type == tls::TLSOPT_NONE) + { + // Create a double GOT entry with an R_386_TLS_DESC + // reloc. The R_386_TLS_DESC reloc is resolved + // lazily, so the GOT entry needs to be in an area in + // .got.plt, not .got. Call got_section to make sure + // the section has been created. + target->got_section(symtab, layout); + Output_data_got<32, false>* got = target->got_tlsdesc_section(); + Reloc_section* rt = target->rel_tls_desc_section(layout); + got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt, + elfcpp::R_386_TLS_DESC, 0); + } + 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_NOFFSET, + target->rel_dyn_section(layout), + elfcpp::R_386_TLS_TPOFF); + } + else if (optimized_type != tls::TLSOPT_TO_LE) + unsupported_reloc_global(object, r_type, gsym); + break; + + case elfcpp::R_386_TLS_DESC_CALL: + 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); + unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32 + ? GOT_TYPE_TLS_OFFSET + : GOT_TYPE_TLS_NOFFSET); + got->add_global_with_rel(gsym, got_type, + 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; + } +} + +// Process relocations for gc. + +void +Target_i386::gc_process_relocs(Symbol_table* symtab, + Layout* layout, + Sized_relobj_file<32, false>* 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) +{ + gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL, + Target_i386::Scan, + Target_i386::Relocatable_size_for_reloc>( + 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. + +void +Target_i386::scan_relocs(Symbol_table* symtab, + Layout* layout, + Sized_relobj_file<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>( + 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, + const Input_objects*, + Symbol_table* symtab) +{ + const Reloc_section* rel_plt = (this->plt_ == NULL + ? NULL + : this->plt_->rel_plt()); + layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt, + this->rel_dyn_, true, false); + + // 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)); + + // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of + // the .got.plt section. + Symbol* sym = this->global_offset_table_; + if (sym != NULL) + { + uint32_t data_size = this->got_plt_->current_data_size(); + symtab->get_sized_symbol<32>(sym)->set_symsize(data_size); + } + + if (parameters->doing_static_link() + && (this->plt_ == NULL || !this->plt_->has_irelative_section())) + { + // If linking statically, make sure that the __rel_iplt symbols + // were defined if necessary, even if we didn't create a PLT. + static const Define_symbol_in_segment syms[] = + { + { + "__rel_iplt_start", // name + elfcpp::PT_LOAD, // segment_type + elfcpp::PF_W, // segment_flags_set + elfcpp::PF(0), // segment_flags_clear + 0, // value + 0, // size + elfcpp::STT_NOTYPE, // type + elfcpp::STB_GLOBAL, // binding + elfcpp::STV_HIDDEN, // visibility + 0, // nonvis + Symbol::SEGMENT_START, // offset_from_base + true // only_if_ref + }, + { + "__rel_iplt_end", // name + elfcpp::PT_LOAD, // segment_type + elfcpp::PF_W, // segment_flags_set + elfcpp::PF(0), // segment_flags_clear + 0, // value + 0, // size + elfcpp::STT_NOTYPE, // type + elfcpp::STB_GLOBAL, // binding + elfcpp::STV_HIDDEN, // visibility + 0, // nonvis + Symbol::SEGMENT_START, // offset_from_base + true // only_if_ref + } + }; + + symtab->define_symbols(layout, 2, syms, + layout->script_options()->saw_sections_clause()); + } +} + +// 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, + unsigned int r_type, + 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; + + int ref_flags = Scan::get_reference_flags(r_type); + + // 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, + Output_section* output_section, + 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 + && r_type != elfcpp::R_386_PC32) + || 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; + } + } + + if (view == NULL) + return true; + + const Sized_relobj_file<32, false>* object = relinfo->object; + + // Pick the value to use for symbols defined in shared objects. + Symbol_value<32> symval; + if (gsym != NULL + && gsym->type() == elfcpp::STT_GNU_IFUNC + && r_type == elfcpp::R_386_32 + && gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)) + && gsym->can_use_relative_reloc(false) + && !gsym->is_from_dynobj() + && !gsym->is_undefined() + && !gsym->is_preemptible()) + { + // In this case we are generating a R_386_IRELATIVE reloc. We + // want to use the real value of the symbol, not the PLT offset. + } + else if (gsym != NULL + && gsym->use_plt_offset(Scan::get_reference_flags(r_type))) + { + symval.set_output_value(target->plt_address_for_global(gsym)); + psymval = &symval; + } + else if (gsym == NULL && psymval->is_ifunc_symbol()) + { + unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); + if (object->local_has_plt_offset(r_sym)) + { + symval.set_output_value(target->plt_address_for_local(object, r_sym)); + 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_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, r_type, true, output_section)) + Relocate_functions<32, false>::rel32(view, object, psymval); + break; + + case elfcpp::R_386_PC32: + if (should_apply_static_reloc(gsym, r_type, true, output_section)) + Relocate_functions<32, false>::pcrel32(view, object, psymval, address); + break; + + case elfcpp::R_386_16: + if (should_apply_static_reloc(gsym, r_type, false, output_section)) + Relocate_functions<32, false>::rel16(view, object, psymval); + break; + + case elfcpp::R_386_PC16: + if (should_apply_static_reloc(gsym, r_type, false, output_section)) + Relocate_functions<32, false>::pcrel16(view, object, psymval, address); + break; + + case elfcpp::R_386_8: + if (should_apply_static_reloc(gsym, r_type, false, output_section)) + Relocate_functions<32, false>::rel8(view, object, psymval); + break; + + case elfcpp::R_386_PC8: + if (should_apply_static_reloc(gsym, r_type, false, output_section)) + Relocate_functions<32, false>::pcrel8(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: + case elfcpp::R_386_IRELATIVE: + // 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_file<32, false>* object = relinfo->object; + + elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0); + + const bool is_final = (gsym == NULL + ? !parameters->options().shared() + : 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) + { + if (tls_segment == NULL) + { + gold_assert(parameters->errors()->error_count() > 0 + || issue_undefined_symbol_error(gsym)); + return; + } + this->tls_gd_to_le(relinfo, relnum, tls_segment, + rel, r_type, value, view, + view_size); + break; + } + else + { + unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE + ? GOT_TYPE_TLS_NOFFSET + : GOT_TYPE_TLS_PAIR); + unsigned int got_offset; + if (gsym != NULL) + { + gold_assert(gsym->has_got_offset(got_type)); + got_offset = gsym->got_offset(got_type) - 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)); + got_offset = (object->local_got_offset(r_sym, got_type) + - target->got_size()); + } + if (optimized_type == tls::TLSOPT_TO_IE) + { + 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: + this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU; + if (optimized_type == tls::TLSOPT_TO_LE) + { + if (tls_segment == NULL) + { + gold_assert(parameters->errors()->error_count() > 0 + || issue_undefined_symbol_error(gsym)); + return; + } + this->tls_desc_gd_to_le(relinfo, relnum, tls_segment, + rel, r_type, value, view, + view_size); + break; + } + else + { + unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE + ? GOT_TYPE_TLS_NOFFSET + : GOT_TYPE_TLS_DESC); + unsigned int got_offset = 0; + if (r_type == elfcpp::R_386_TLS_GOTDESC + && optimized_type == tls::TLSOPT_NONE) + { + // We created GOT entries in the .got.tlsdesc portion of + // the .got.plt section, but the offset stored in the + // symbol is the offset within .got.tlsdesc. + got_offset = (target->got_size() + + target->got_plt_section()->data_size()); + } + if (gsym != NULL) + { + gold_assert(gsym->has_got_offset(got_type)); + got_offset += gsym->got_offset(got_type) - 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)); + got_offset += (object->local_got_offset(r_sym, got_type) + - target->got_size()); + } + if (optimized_type == tls::TLSOPT_TO_IE) + { + if (tls_segment == NULL) + { + gold_assert(parameters->errors()->error_count() > 0 + || issue_undefined_symbol_error(gsym)); + return; + } + this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type, + got_offset, view, view_size); + break; + } + else if (optimized_type == tls::TLSOPT_NONE) + { + if (r_type == elfcpp::R_386_TLS_GOTDESC) + { + // 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_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) + { + if (tls_segment == NULL) + { + gold_assert(parameters->errors()->error_count() > 0 + || issue_undefined_symbol_error(gsym)); + return; + } + 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 + if (optimized_type == tls::TLSOPT_TO_LE) + { + // This reloc can appear in debugging sections, in which + // case we must not convert to local-exec. We decide what + // to do based on whether the section is marked as + // containing executable code. That is what the GNU linker + // does as well. + elfcpp::Shdr<32, false> shdr(relinfo->data_shdr); + if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0) + { + if (tls_segment == NULL) + { + gold_assert(parameters->errors()->error_count() > 0 + || issue_undefined_symbol_error(gsym)); + return; + } + 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) + { + if (tls_segment == NULL) + { + gold_assert(parameters->errors()->error_count() > 0 + || issue_undefined_symbol_error(gsym)); + return; + } + 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_type = (r_type == elfcpp::R_386_TLS_IE_32 + ? GOT_TYPE_TLS_OFFSET + : GOT_TYPE_TLS_NOFFSET); + unsigned int got_offset; + if (gsym != NULL) + { + gold_assert(gsym->has_got_offset(got_type)); + got_offset = gsym->got_offset(got_type); + } + 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)); + got_offset = object->local_got_offset(r_sym, got_type); + } + // 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()) + { + if (tls_segment == NULL) + { + gold_assert(parameters->errors()->error_count() > 0 + || issue_undefined_symbol_error(gsym)); + return; + } + 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()) + { + if (tls_segment == NULL) + { + gold_assert(parameters->errors()->error_count() > 0 + || issue_undefined_symbol_error(gsym)); + return; + } + 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*, + 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 the first (SIB) form. + tls::check_tls(relinfo, relnum, rel.get_r_offset(), 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); + } + } + + 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_GOTDESC or TLS_DESC_CALL +// General-Dynamic to a Local-Exec. + +inline void +Target_i386::Relocate::tls_desc_gd_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) +{ + if (r_type == elfcpp::R_386_TLS_GOTDESC) + { + // leal foo@TLSDESC(%ebx), %eax + // ==> leal foo@NTPOFF, %eax + tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); + tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4); + tls::check_tls(relinfo, relnum, rel.get_r_offset(), + view[-2] == 0x8d && view[-1] == 0x83); + view[-1] = 0x05; + value -= tls_segment->memsz(); + Relocate_functions<32, false>::rel32(view, value); + } + else + { + // call *foo@TLSCALL(%eax) + // ==> nop; nop + gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL); + tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2); + tls::check_tls(relinfo, relnum, rel.get_r_offset(), + view[0] == 0xff && view[1] == 0x10); + view[0] = 0x66; + view[1] = 0x90; + } +} + +// Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL +// General-Dynamic to an Initial-Exec. + +inline void +Target_i386::Relocate::tls_desc_gd_to_ie( + const Relocate_info<32, false>* relinfo, + size_t relnum, + Output_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) +{ + if (r_type == elfcpp::R_386_TLS_GOTDESC) + { + // leal foo@TLSDESC(%ebx), %eax + // ==> movl 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, 4); + tls::check_tls(relinfo, relnum, rel.get_r_offset(), + view[-2] == 0x8d && view[-1] == 0x83); + view[-2] = 0x8b; + Relocate_functions<32, false>::rel32(view, value); + } + else + { + // call *foo@TLSCALL(%eax) + // ==> nop; nop + gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL); + tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2); + tls::check_tls(relinfo, relnum, rel.get_r_offset(), + view[0] == 0xff && view[1] == 0x10); + view[0] = 0x66; + view[1] = 0x90; + } +} + +// 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, + const Reloc_symbol_changes* reloc_symbol_changes) +{ + gold_assert(sh_type == elfcpp::SHT_REL); + + gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL, + Target_i386::Relocate, gold::Default_comdat_behavior>( + 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. + +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_IRELATIVE: + 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(Symbol_table* symtab, + Layout* layout, + Sized_relobj_file<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>( + symtab, + layout, + object, + data_shndx, + prelocs, + reloc_count, + output_section, + needs_special_offset_handling, + local_symbol_count, + plocal_symbols, + rr); +} + +// Emit relocations for a section. + +void +Target_i386::relocate_relocs( + const Relocate_info<32, false>* relinfo, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + elfcpp::Elf_types<32>::Elf_Off 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_relocs<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_address_for_global(gsym); +} + +// 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, static_cast<char>(0x90))); + } + + // Nop sequences of various lengths. + const char nop1[1] = { '\x90' }; // nop + const char nop2[2] = { '\x66', '\x90' }; // xchg %ax %ax + const char nop3[3] = { '\x8d', '\x76', '\x00' }; // leal 0(%esi),%esi + const char nop4[4] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi + '\x00'}; + const char nop5[5] = { '\x90', '\x8d', '\x74', // nop + '\x26', '\x00' }; // leal 0(%esi,1),%esi + const char nop6[6] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi + '\x00', '\x00', '\x00' }; + const char nop7[7] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi + '\x00', '\x00', '\x00', + '\x00' }; + const char nop8[8] = { '\x90', '\x8d', '\xb4', // nop + '\x26', '\x00', '\x00', // leal 0L(%esi,1),%esi + '\x00', '\x00' }; + const char nop9[9] = { '\x89', '\xf6', '\x8d', // movl %esi,%esi + '\xbc', '\x27', '\x00', // leal 0L(%edi,1),%edi + '\x00', '\x00', '\x00' }; + const char nop10[10] = { '\x8d', '\x76', '\x00', // leal 0(%esi),%esi + '\x8d', '\xbc', '\x27', // leal 0L(%edi,1),%edi + '\x00', '\x00', '\x00', + '\x00' }; + const char nop11[11] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi + '\x00', '\x8d', '\xbc', // leal 0L(%edi,1),%edi + '\x27', '\x00', '\x00', + '\x00', '\x00' }; + const char nop12[12] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi + '\x00', '\x00', '\x00', // leal 0L(%edi),%edi + '\x8d', '\xbf', '\x00', + '\x00', '\x00', '\x00' }; + const char nop13[13] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi + '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi + '\x8d', '\xbc', '\x27', + '\x00', '\x00', '\x00', + '\x00' }; + const char nop14[14] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi + '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi + '\x00', '\x8d', '\xbc', + '\x27', '\x00', '\x00', + '\x00', '\x00' }; + const char nop15[15] = { '\xeb', '\x0d', '\x90', // jmp .+15 + '\x90', '\x90', '\x90', // nop,nop,nop,... + '\x90', '\x90', '\x90', + '\x90', '\x90', '\x90', + '\x90', '\x90', '\x90' }; + + 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); +} + +// Return the value to use for the base of a DW_EH_PE_datarel offset +// in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their +// assembler can not write out the difference between two labels in +// different sections, so instead of using a pc-relative value they +// use an offset from the GOT. + +uint64_t +Target_i386::do_ehframe_datarel_base() const +{ + gold_assert(this->global_offset_table_ != NULL); + Symbol* sym = this->global_offset_table_; + Sized_symbol<32>* ssym = static_cast<Sized_symbol<32>*>(sym); + return ssym->value(); +} + +// Return whether SYM should be treated as a call to a non-split +// function. We don't want that to be true of a call to a +// get_pc_thunk function. + +bool +Target_i386::do_is_call_to_non_split(const Symbol* sym, unsigned int) const +{ + return (sym->type() == elfcpp::STT_FUNC + && !is_prefix_of("__i686.get_pc_thunk.", sym->name())); +} + +// FNOFFSET in section SHNDX in OBJECT is the start of a function +// compiled with -fsplit-stack. The function calls non-split-stack +// code. We have to change the function so that it always ensures +// that it has enough stack space to run some random function. + +void +Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx, + section_offset_type fnoffset, + section_size_type fnsize, + unsigned char* view, + section_size_type view_size, + std::string* from, + std::string* to) const +{ + // The function starts with a comparison of the stack pointer and a + // field in the TCB. This is followed by a jump. + + // cmp %gs:NN,%esp + if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3) + && fnsize > 7) + { + // We will call __morestack if the carry flag is set after this + // comparison. We turn the comparison into an stc instruction + // and some nops. + view[fnoffset] = '\xf9'; + this->set_view_to_nop(view, view_size, fnoffset + 1, 6); + } + // lea NN(%esp),%ecx + // lea NN(%esp),%edx + else if ((this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3) + || this->match_view(view, view_size, fnoffset, "\x8d\x94\x24", 3)) + && fnsize > 7) + { + // This is loading an offset from the stack pointer for a + // comparison. The offset is negative, so we decrease the + // offset by the amount of space we need for the stack. This + // means we will avoid calling __morestack if there happens to + // be plenty of space on the stack already. + unsigned char* pval = view + fnoffset + 3; + uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval); + val -= parameters->options().split_stack_adjust_size(); + elfcpp::Swap_unaligned<32, false>::writeval(pval, val); + } + else + { + if (!object->has_no_split_stack()) + object->error(_("failed to match split-stack sequence at " + "section %u offset %0zx"), + shndx, static_cast<size_t>(fnoffset)); + return; + } + + // We have to change the function so that it calls + // __morestack_non_split instead of __morestack. The former will + // allocate additional stack space. + *from = "__morestack"; + *to = "__morestack_non_split"; +} + +// The selector for i386 object files. Note this is never instantiated +// directly. It's only used in Target_selector_i386_nacl, below. + +class Target_selector_i386 : public Target_selector_freebsd +{ +public: + Target_selector_i386() + : Target_selector_freebsd(elfcpp::EM_386, 32, false, + "elf32-i386", "elf32-i386-freebsd", + "elf_i386") + { } + + Target* + do_instantiate_target() + { return new Target_i386(); } +}; + +// NaCl variant. It uses different PLT contents. + +class Output_data_plt_i386_nacl : public Output_data_plt_i386 +{ + public: + Output_data_plt_i386_nacl(Layout* layout, + Output_data_space* got_plt, + Output_data_space* got_irelative) + : Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative) + { } + + protected: + virtual unsigned int + do_get_plt_entry_size() const + { return plt_entry_size; } + + virtual void + do_add_eh_frame(Layout* layout) + { + layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size, + plt_eh_frame_fde, plt_eh_frame_fde_size); + } + + // The size of an entry in the PLT. + static const int plt_entry_size = 64; + + // The .eh_frame unwind information for the PLT. + static const int plt_eh_frame_fde_size = 32; + static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size]; +}; + +class Output_data_plt_i386_nacl_exec : public Output_data_plt_i386_nacl +{ +public: + Output_data_plt_i386_nacl_exec(Layout* layout, + Output_data_space* got_plt, + Output_data_space* got_irelative) + : Output_data_plt_i386_nacl(layout, got_plt, got_irelative) + { } + + protected: + virtual void + do_fill_first_plt_entry(unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr got_address); + + virtual unsigned int + do_fill_plt_entry(unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr got_address, + unsigned int got_offset, + unsigned int plt_offset, + unsigned int plt_rel_offset); + + private: + // The first entry in the PLT for an executable. + static const unsigned char first_plt_entry[plt_entry_size]; + + // Other entries in the PLT for an executable. + static const unsigned char plt_entry[plt_entry_size]; +}; + +class Output_data_plt_i386_nacl_dyn : public Output_data_plt_i386_nacl +{ + public: + Output_data_plt_i386_nacl_dyn(Layout* layout, + Output_data_space* got_plt, + Output_data_space* got_irelative) + : Output_data_plt_i386_nacl(layout, got_plt, got_irelative) + { } + + protected: + virtual void + do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr); + + virtual unsigned int + do_fill_plt_entry(unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr, + unsigned int got_offset, + unsigned int plt_offset, + unsigned int plt_rel_offset); + + private: + // The first entry in the PLT for a shared object. + static const unsigned char first_plt_entry[plt_entry_size]; + + // Other entries in the PLT for a shared object. + static const unsigned char plt_entry[plt_entry_size]; +}; + +class Target_i386_nacl : public Target_i386 +{ + public: + Target_i386_nacl() + : Target_i386(&i386_nacl_info) + { } + + protected: + virtual Output_data_plt_i386* + do_make_data_plt(Layout* layout, + Output_data_space* got_plt, + Output_data_space* got_irelative, + bool dyn) + { + if (dyn) + return new Output_data_plt_i386_nacl_dyn(layout, got_plt, got_irelative); + else + return new Output_data_plt_i386_nacl_exec(layout, got_plt, got_irelative); + } + + virtual std::string + do_code_fill(section_size_type length) const; + + private: + static const Target::Target_info i386_nacl_info; +}; + +const Target::Target_info Target_i386_nacl::i386_nacl_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 + true, // can_icf_inline_merge_sections + '\0', // wrap_char + "/lib/ld-nacl-x86-32.so.1", // dynamic_linker + 0x20000, // default_text_segment_address + 0x10000, // abi_pagesize (overridable by -z max-page-size) + 0x10000, // common_pagesize (overridable by -z common-page-size) + true, // isolate_execinstr + 0x10000000, // rosegment_gap + elfcpp::SHN_UNDEF, // small_common_shndx + elfcpp::SHN_UNDEF, // large_common_shndx + 0, // small_common_section_flags + 0, // large_common_section_flags + NULL, // attributes_section + NULL, // attributes_vendor + "_start" // entry_symbol_name +}; + +#define NACLMASK 0xe0 // 32-byte alignment mask + +const unsigned char +Output_data_plt_i386_nacl_exec::first_plt_entry[plt_entry_size] = +{ + 0xff, 0x35, // pushl contents of memory address + 0, 0, 0, 0, // replaced with address of .got + 4 + 0x8b, 0x0d, // movl contents of address, %ecx + 0, 0, 0, 0, // replaced with address of .got + 8 + 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx + 0xff, 0xe1, // jmp *%ecx + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90 +}; + +void +Output_data_plt_i386_nacl_exec::do_fill_first_plt_entry( + unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr got_address) +{ + memcpy(pov, 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); +} + +// The first entry in the PLT for a shared object. + +const unsigned char +Output_data_plt_i386_nacl_dyn::first_plt_entry[plt_entry_size] = +{ + 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx) + 0x8b, 0x4b, 0x08, // mov 0x8(%ebx), %ecx + 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx + 0xff, 0xe1, // jmp *%ecx + 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90, // nops + 0x90, 0x90, 0x90, 0x90, 0x90 // nops +}; + +void +Output_data_plt_i386_nacl_dyn::do_fill_first_plt_entry( + unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr) +{ + memcpy(pov, first_plt_entry, plt_entry_size); +} + +// Subsequent entries in the PLT for an executable. + +const unsigned char +Output_data_plt_i386_nacl_exec::plt_entry[plt_entry_size] = +{ + 0x8b, 0x0d, // movl contents of address, %ecx */ + 0, 0, 0, 0, // replaced with address of symbol in .got + 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx + 0xff, 0xe1, // jmp *%ecx + + // Pad to the next 32-byte boundary with nop instructions. + 0x90, + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, + + // Lazy GOT entries point here (32-byte aligned). + 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 + + // Pad to the next 32-byte boundary with nop instructions. + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, + 0x90, 0x90 +}; + +unsigned int +Output_data_plt_i386_nacl_exec::do_fill_plt_entry( + unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr got_address, + unsigned int got_offset, + unsigned int plt_offset, + unsigned int plt_rel_offset) +{ + memcpy(pov, plt_entry, plt_entry_size); + elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, + got_address + got_offset); + elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_rel_offset); + elfcpp::Swap<32, false>::writeval(pov + 38, - (plt_offset + 38 + 4)); + return 32; +} + +// Subsequent entries in the PLT for a shared object. + +const unsigned char +Output_data_plt_i386_nacl_dyn::plt_entry[plt_entry_size] = +{ + 0x8b, 0x8b, // movl offset(%ebx), %ecx + 0, 0, 0, 0, // replaced with offset of symbol in .got + 0x83, 0xe1, 0xe0, // andl $NACLMASK, %ecx + 0xff, 0xe1, // jmp *%ecx + + // Pad to the next 32-byte boundary with nop instructions. + 0x90, + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, + + // Lazy GOT entries point here (32-byte aligned). + 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. + + // Pad to the next 32-byte boundary with nop instructions. + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, + 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, + 0x90, 0x90 +}; + +unsigned int +Output_data_plt_i386_nacl_dyn::do_fill_plt_entry( + unsigned char* pov, + elfcpp::Elf_types<32>::Elf_Addr, + unsigned int got_offset, + unsigned int plt_offset, + unsigned int plt_rel_offset) +{ + memcpy(pov, plt_entry, plt_entry_size); + elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset); + elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_rel_offset); + elfcpp::Swap<32, false>::writeval(pov + 38, - (plt_offset + 38 + 4)); + return 32; +} + +const unsigned char +Output_data_plt_i386_nacl::plt_eh_frame_fde[plt_eh_frame_fde_size] = +{ + 0, 0, 0, 0, // Replaced with offset to .plt. + 0, 0, 0, 0, // Replaced with size of .plt. + 0, // Augmentation size. + elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8. + elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6. + elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12. + elfcpp::DW_CFA_advance_loc + 58, // Advance 58 to __PLT__ + 64. + elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression. + 13, // Block length. + elfcpp::DW_OP_breg4, 4, // Push %esp + 4. + elfcpp::DW_OP_breg8, 0, // Push %eip. + elfcpp::DW_OP_const1u, 63, // Push 0x3f. + elfcpp::DW_OP_and, // & (%eip & 0x3f). + elfcpp::DW_OP_const1u, 37, // Push 0x25. + elfcpp::DW_OP_ge, // >= ((%eip & 0x3f) >= 0x25) + elfcpp::DW_OP_lit2, // Push 2. + elfcpp::DW_OP_shl, // << (((%eip & 0x3f) >= 0x25) << 2) + elfcpp::DW_OP_plus, // + ((((%eip&0x3f)>=0x25)<<2)+%esp+4 + elfcpp::DW_CFA_nop, // Align to 32 bytes. + elfcpp::DW_CFA_nop +}; + +// Return a string used to fill a code section with nops. +// For NaCl, long NOPs are only valid if they do not cross +// bundle alignment boundaries, so keep it simple with one-byte NOPs. +std::string +Target_i386_nacl::do_code_fill(section_size_type length) const +{ + return std::string(length, static_cast<char>(0x90)); +} + +// The selector for i386-nacl object files. + +class Target_selector_i386_nacl + : public Target_selector_nacl<Target_selector_i386, Target_i386_nacl> +{ + public: + Target_selector_i386_nacl() + : Target_selector_nacl<Target_selector_i386, + Target_i386_nacl>("x86-32", + "elf32-i386-nacl", + "elf_i386_nacl") + { } +}; + +Target_selector_i386_nacl target_selector_i386; + +} // End anonymous namespace. |