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- // i386.cc -- i386 target support for gold.
- // Copyright (C) 2006-2015 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 .got.plt section.
- class Output_data_got_plt_i386 : public Output_section_data_build
- {
- public:
- Output_data_got_plt_i386(Layout* layout)
- : Output_section_data_build(4),
- layout_(layout)
- { }
- protected:
- // Write out the PLT data.
- void
- do_write(Output_file*);
- // Write to a map file.
- void
- do_print_to_mapfile(Mapfile* mapfile) const
- { mapfile->print_output_data(this, "** GOT PLT"); }
- private:
- // A pointer to the Layout class, so that we can find the .dynamic
- // section when we write out the GOT PLT section.
- Layout* layout_;
- };
- // 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_got_plt_i386*, 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;
- };
- // 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_got_plt_i386* 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_got_plt_i386* 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_got_plt_i386* 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_got_plt_i386* 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_got_plt_i386* 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_got_plt_i386* 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);
- // Check if relocation against this symbol is a candidate for
- // conversion from
- // mov foo@GOT(%reg), %reg
- // to
- // lea foo@GOTOFF(%reg), %reg.
- static bool
- can_convert_mov_to_lea(const Symbol* gsym)
- {
- gold_assert(gsym != NULL);
- return (gsym->type() != elfcpp::STT_GNU_IFUNC
- && !gsym->is_undefined ()
- && !gsym->is_from_dynobj()
- && !gsym->is_preemptible()
- && (!parameters->options().shared()
- || (gsym->visibility() != elfcpp::STV_DEFAULT
- && gsym->visibility() != elfcpp::STV_PROTECTED)
- || parameters->options().Bsymbolic())
- && strcmp(gsym->name(), "_DYNAMIC") != 0);
- }
- // 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_got_plt_i386*
- 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_got_plt_i386* 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_got_plt_i386(layout);
- 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_;
- }
- // Write the first three reserved words of the .got.plt section.
- // The remainder of the section is written while writing the PLT
- // in Output_data_plt_i386::do_write.
- void
- Output_data_got_plt_i386::do_write(Output_file* of)
- {
- // 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.
- const off_t got_file_offset = this->offset();
- gold_assert(this->data_size() >= 12);
- unsigned char* const got_view = of->get_output_view(got_file_offset, 12);
- Output_section* dynamic = this->layout_->dynamic_section();
- uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
- elfcpp::Swap<32, false>::writeval(got_view, dynamic_addr);
- memset(got_view + 4, 0, 8);
- of->write_output_view(got_file_offset, 12, got_view);
- }
- // 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_got_plt_i386* got_plt,
- Output_data_space* got_irelative)
- : Output_section_data(addralign),
- 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();
- // The first three entries in the GOT are reserved, and are written
- // by Output_data_got_plt_i386::do_write.
- unsigned char* got_pov = got_view + 12;
- 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:
- {
- // We need GOT section.
- Output_data_got<32, false>* got = target->got_section(symtab, layout);
- // If the relocation symbol isn't IFUNC,
- // and is local, then we will convert
- // mov foo@GOT(%reg), %reg
- // to
- // lea foo@GOTOFF(%reg), %reg
- // in Relocate::relocate.
- if (reloc.get_r_offset() >= 2
- && lsym.get_st_type() != elfcpp::STT_GNU_IFUNC)
- {
- section_size_type stype;
- const unsigned char* view = object->section_contents(data_shndx,
- &stype, true);
- if (view[reloc.get_r_offset() - 2] == 0x8b)
- break;
- }
- // Otherwise, the symbol requires a GOT entry.
- 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 (!parameters->options().output_is_position_independent()
- && 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 (parameters->options().output_is_executable()
- && 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 section.
- Output_data_got<32, false>* got = target->got_section(symtab, layout);
- // If we convert this from
- // mov foo@GOT(%reg), %reg
- // to
- // lea foo@GOTOFF(%reg), %reg
- // in Relocate::relocate, then there is nothing to do here.
- if (reloc.get_r_offset() >= 2
- && Target_i386::can_convert_mov_to_lea(gsym))
- {
- section_size_type stype;
- const unsigned char* view = object->section_contents(data_shndx,
- &stype, true);
- if (view[reloc.get_r_offset() - 2] == 0x8b)
- break;
- }
- 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;
- }
- }
- 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:
- // Convert
- // mov foo@GOT(%reg), %reg
- // to
- // lea foo@GOTOFF(%reg), %reg
- // if possible.
- if (rel.get_r_offset() >= 2
- && view[-2] == 0x8b
- && ((gsym == NULL && !psymval->is_ifunc_symbol())
- || (gsym != NULL
- && Target_i386::can_convert_mov_to_lea(gsym))))
- {
- view[-2] = 0x8d;
- elfcpp::Elf_types<32>::Elf_Addr value;
- value = (psymval->value(object, 0)
- - target->got_plt_section()->address());
- Relocate_functions<32, false>::rel32(view, value);
- }
- else
- {
- // 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.
- unsigned int got_offset = 0;
- 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());
- }
- 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
- // leal foo(%ebx),%eax; call ___tls_get_addr; nop
- // ==> 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;
- 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)));
- roff = 5;
- }
- else
- {
- tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 10);
- tls::check_tls(relinfo, relnum, rel.get_r_offset(),
- (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
- tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[9] == 0x90);
- roff = 6;
- }
- memcpy(view + roff - 8, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
- 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_got_plt_i386* 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_got_plt_i386* 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_got_plt_i386* 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_got_plt_i386* 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;
- // IAMCU variant. It uses EM_IAMCU, not EM_386.
- class Target_iamcu : public Target_i386
- {
- public:
- Target_iamcu()
- : Target_i386(&iamcu_info)
- { }
- private:
- // Information about this specific target which we pass to the
- // general Target structure.
- static const Target::Target_info iamcu_info;
- };
- const Target::Target_info Target_iamcu::iamcu_info =
- {
- 32, // size
- false, // is_big_endian
- elfcpp::EM_IAMCU, // 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
- };
- class Target_selector_iamcu : public Target_selector
- {
- public:
- Target_selector_iamcu()
- : Target_selector(elfcpp::EM_IAMCU, 32, false, "elf32-iamcu",
- "elf_iamcu")
- { }
- Target*
- do_instantiate_target()
- { return new Target_iamcu(); }
- };
- Target_selector_iamcu target_selector_iamcu;
- } // End anonymous namespace.
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