ed700649d0
gold/ PR gold/16111 * i386.cc (Target_i386): Add check for fully-resolved symbol for R_386_GOTOFF.
4418 lines
138 KiB
C++
4418 lines
138 KiB
C++
// i386.cc -- i386 target support for gold.
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// Copyright (C) 2006-2016 Free Software Foundation, Inc.
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// Written by Ian Lance Taylor <iant@google.com>.
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// This file is part of gold.
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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// MA 02110-1301, USA.
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#include "gold.h"
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#include <cstring>
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#include "elfcpp.h"
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#include "dwarf.h"
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#include "parameters.h"
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#include "reloc.h"
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#include "i386.h"
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#include "object.h"
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#include "symtab.h"
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#include "layout.h"
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#include "output.h"
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#include "copy-relocs.h"
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#include "target.h"
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#include "target-reloc.h"
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#include "target-select.h"
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#include "tls.h"
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#include "freebsd.h"
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#include "nacl.h"
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#include "gc.h"
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namespace
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{
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using namespace gold;
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// A class to handle the .got.plt section.
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class Output_data_got_plt_i386 : public Output_section_data_build
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{
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public:
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Output_data_got_plt_i386(Layout* layout)
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: Output_section_data_build(4),
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layout_(layout)
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{ }
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protected:
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// Write out the PLT data.
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void
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do_write(Output_file*);
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// Write to a map file.
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void
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do_print_to_mapfile(Mapfile* mapfile) const
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{ mapfile->print_output_data(this, "** GOT PLT"); }
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private:
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// A pointer to the Layout class, so that we can find the .dynamic
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// section when we write out the GOT PLT section.
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Layout* layout_;
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};
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// A class to handle the PLT data.
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// This is an abstract base class that handles most of the linker details
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// but does not know the actual contents of PLT entries. The derived
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// classes below fill in those details.
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class Output_data_plt_i386 : public Output_section_data
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{
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public:
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typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
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Output_data_plt_i386(Layout*, uint64_t addralign,
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Output_data_got_plt_i386*, Output_data_space*);
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// Add an entry to the PLT.
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void
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add_entry(Symbol_table*, Layout*, Symbol* gsym);
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// Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
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unsigned int
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add_local_ifunc_entry(Symbol_table*, Layout*,
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Sized_relobj_file<32, false>* relobj,
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unsigned int local_sym_index);
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// Return the .rel.plt section data.
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Reloc_section*
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rel_plt() const
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{ return this->rel_; }
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// Return where the TLS_DESC relocations should go.
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Reloc_section*
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rel_tls_desc(Layout*);
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// Return where the IRELATIVE relocations should go.
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Reloc_section*
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rel_irelative(Symbol_table*, Layout*);
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// Return whether we created a section for IRELATIVE relocations.
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bool
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has_irelative_section() const
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{ return this->irelative_rel_ != NULL; }
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// Return the number of PLT entries.
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unsigned int
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entry_count() const
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{ return this->count_ + this->irelative_count_; }
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// Return the offset of the first non-reserved PLT entry.
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unsigned int
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first_plt_entry_offset()
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{ return this->get_plt_entry_size(); }
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// Return the size of a PLT entry.
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unsigned int
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get_plt_entry_size() const
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{ return this->do_get_plt_entry_size(); }
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// Return the PLT address to use for a global symbol.
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uint64_t
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address_for_global(const Symbol*);
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// Return the PLT address to use for a local symbol.
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uint64_t
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address_for_local(const Relobj*, unsigned int symndx);
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// Add .eh_frame information for the PLT.
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void
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add_eh_frame(Layout* layout)
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{ this->do_add_eh_frame(layout); }
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protected:
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// Fill the first PLT entry, given the pointer to the PLT section data
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// and the runtime address of the GOT.
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void
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fill_first_plt_entry(unsigned char* pov,
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elfcpp::Elf_types<32>::Elf_Addr got_address)
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{ this->do_fill_first_plt_entry(pov, got_address); }
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// Fill a normal PLT entry, given the pointer to the entry's data in the
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// section, the runtime address of the GOT, the offset into the GOT of
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// the corresponding slot, the offset into the relocation section of the
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// corresponding reloc, and the offset of this entry within the whole
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// PLT. Return the offset from this PLT entry's runtime address that
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// should be used to compute the initial value of the GOT slot.
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unsigned int
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fill_plt_entry(unsigned char* pov,
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elfcpp::Elf_types<32>::Elf_Addr got_address,
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unsigned int got_offset,
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unsigned int plt_offset,
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unsigned int plt_rel_offset)
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{
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return this->do_fill_plt_entry(pov, got_address, got_offset,
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plt_offset, plt_rel_offset);
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}
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virtual unsigned int
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do_get_plt_entry_size() const = 0;
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virtual void
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do_fill_first_plt_entry(unsigned char* pov,
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elfcpp::Elf_types<32>::Elf_Addr got_address) = 0;
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virtual unsigned int
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do_fill_plt_entry(unsigned char* pov,
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elfcpp::Elf_types<32>::Elf_Addr got_address,
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unsigned int got_offset,
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unsigned int plt_offset,
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unsigned int plt_rel_offset) = 0;
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virtual void
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do_add_eh_frame(Layout*) = 0;
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void
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do_adjust_output_section(Output_section* os);
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// Write to a map file.
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void
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do_print_to_mapfile(Mapfile* mapfile) const
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{ mapfile->print_output_data(this, _("** PLT")); }
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// The .eh_frame unwind information for the PLT.
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// The CIE is common across variants of the PLT format.
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static const int plt_eh_frame_cie_size = 16;
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static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size];
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private:
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// Set the final size.
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void
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set_final_data_size()
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{
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this->set_data_size((this->count_ + this->irelative_count_ + 1)
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* this->get_plt_entry_size());
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}
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// Write out the PLT data.
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void
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do_write(Output_file*);
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// We keep a list of global STT_GNU_IFUNC symbols, each with its
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// offset in the GOT.
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struct Global_ifunc
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{
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Symbol* sym;
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unsigned int got_offset;
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};
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// We keep a list of local STT_GNU_IFUNC symbols, each with its
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// offset in the GOT.
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struct Local_ifunc
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{
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Sized_relobj_file<32, false>* object;
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unsigned int local_sym_index;
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unsigned int got_offset;
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};
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// The reloc section.
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Reloc_section* rel_;
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// The TLS_DESC relocations, if necessary. These must follow the
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// regular PLT relocs.
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Reloc_section* tls_desc_rel_;
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// The IRELATIVE relocations, if necessary. These must follow the
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// regular relocatoins and the TLS_DESC relocations.
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Reloc_section* irelative_rel_;
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// The .got.plt section.
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Output_data_got_plt_i386* got_plt_;
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// The part of the .got.plt section used for IRELATIVE relocs.
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Output_data_space* got_irelative_;
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// The number of PLT entries.
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unsigned int count_;
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// Number of PLT entries with R_386_IRELATIVE relocs. These follow
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// the regular PLT entries.
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unsigned int irelative_count_;
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// Global STT_GNU_IFUNC symbols.
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std::vector<Global_ifunc> global_ifuncs_;
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// Local STT_GNU_IFUNC symbols.
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std::vector<Local_ifunc> local_ifuncs_;
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};
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// This is an abstract class for the standard PLT layout.
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// The derived classes below handle the actual PLT contents
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// for the executable (non-PIC) and shared-library (PIC) cases.
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// The unwind information is uniform across those two, so it's here.
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class Output_data_plt_i386_standard : public Output_data_plt_i386
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{
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public:
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Output_data_plt_i386_standard(Layout* layout,
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Output_data_got_plt_i386* got_plt,
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Output_data_space* got_irelative)
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: Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative)
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{ }
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protected:
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virtual unsigned int
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do_get_plt_entry_size() const
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{ return plt_entry_size; }
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virtual void
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do_add_eh_frame(Layout* layout)
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{
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layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size,
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plt_eh_frame_fde, plt_eh_frame_fde_size);
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}
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// The size of an entry in the PLT.
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static const int plt_entry_size = 16;
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// The .eh_frame unwind information for the PLT.
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static const int plt_eh_frame_fde_size = 32;
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static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
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};
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// Actually fill the PLT contents for an executable (non-PIC).
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class Output_data_plt_i386_exec : public Output_data_plt_i386_standard
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{
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public:
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Output_data_plt_i386_exec(Layout* layout,
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Output_data_got_plt_i386* got_plt,
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Output_data_space* got_irelative)
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: Output_data_plt_i386_standard(layout, got_plt, got_irelative)
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{ }
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protected:
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virtual void
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do_fill_first_plt_entry(unsigned char* pov,
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elfcpp::Elf_types<32>::Elf_Addr got_address);
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virtual unsigned int
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do_fill_plt_entry(unsigned char* pov,
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elfcpp::Elf_types<32>::Elf_Addr got_address,
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unsigned int got_offset,
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unsigned int plt_offset,
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unsigned int plt_rel_offset);
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private:
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// The first entry in the PLT for an executable.
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static const unsigned char first_plt_entry[plt_entry_size];
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// Other entries in the PLT for an executable.
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static const unsigned char plt_entry[plt_entry_size];
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};
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// Actually fill the PLT contents for a shared library (PIC).
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class Output_data_plt_i386_dyn : public Output_data_plt_i386_standard
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{
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public:
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Output_data_plt_i386_dyn(Layout* layout,
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Output_data_got_plt_i386* got_plt,
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Output_data_space* got_irelative)
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: Output_data_plt_i386_standard(layout, got_plt, got_irelative)
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{ }
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protected:
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virtual void
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do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr);
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virtual unsigned int
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do_fill_plt_entry(unsigned char* pov,
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elfcpp::Elf_types<32>::Elf_Addr,
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unsigned int got_offset,
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unsigned int plt_offset,
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unsigned int plt_rel_offset);
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private:
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// The first entry in the PLT for a shared object.
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static const unsigned char first_plt_entry[plt_entry_size];
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// Other entries in the PLT for a shared object.
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static const unsigned char plt_entry[plt_entry_size];
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};
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// The i386 target class.
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// TLS info comes from
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// http://people.redhat.com/drepper/tls.pdf
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// http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
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class Target_i386 : public Sized_target<32, false>
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{
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public:
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typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
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Target_i386(const Target::Target_info* info = &i386_info)
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: Sized_target<32, false>(info),
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got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL),
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got_tlsdesc_(NULL), global_offset_table_(NULL), rel_dyn_(NULL),
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rel_irelative_(NULL), copy_relocs_(elfcpp::R_386_COPY),
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got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
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{ }
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// Process the relocations to determine unreferenced sections for
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// garbage collection.
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void
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gc_process_relocs(Symbol_table* symtab,
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Layout* layout,
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Sized_relobj_file<32, false>* object,
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unsigned int data_shndx,
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unsigned int sh_type,
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const unsigned char* prelocs,
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size_t reloc_count,
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Output_section* output_section,
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bool needs_special_offset_handling,
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size_t local_symbol_count,
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const unsigned char* plocal_symbols);
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// Scan the relocations to look for symbol adjustments.
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void
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scan_relocs(Symbol_table* symtab,
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Layout* layout,
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Sized_relobj_file<32, false>* object,
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unsigned int data_shndx,
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unsigned int sh_type,
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const unsigned char* prelocs,
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size_t reloc_count,
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Output_section* output_section,
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bool needs_special_offset_handling,
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size_t local_symbol_count,
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const unsigned char* plocal_symbols);
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// Finalize the sections.
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void
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do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
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// Return the value to use for a dynamic which requires special
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// treatment.
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uint64_t
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do_dynsym_value(const Symbol*) const;
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// Relocate a section.
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void
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relocate_section(const Relocate_info<32, false>*,
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unsigned int sh_type,
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const unsigned char* prelocs,
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size_t reloc_count,
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Output_section* output_section,
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bool needs_special_offset_handling,
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unsigned char* view,
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elfcpp::Elf_types<32>::Elf_Addr view_address,
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section_size_type view_size,
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const Reloc_symbol_changes*);
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// Scan the relocs during a relocatable link.
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void
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scan_relocatable_relocs(Symbol_table* symtab,
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Layout* layout,
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Sized_relobj_file<32, false>* object,
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unsigned int data_shndx,
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unsigned int sh_type,
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const unsigned char* prelocs,
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size_t reloc_count,
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Output_section* output_section,
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bool needs_special_offset_handling,
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size_t local_symbol_count,
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const unsigned char* plocal_symbols,
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Relocatable_relocs*);
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// Scan the relocs for --emit-relocs.
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void
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emit_relocs_scan(Symbol_table* symtab,
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Layout* layout,
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Sized_relobj_file<32, false>* object,
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unsigned int data_shndx,
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unsigned int sh_type,
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const unsigned char* prelocs,
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size_t reloc_count,
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Output_section* output_section,
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bool needs_special_offset_handling,
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size_t local_symbol_count,
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const unsigned char* plocal_syms,
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Relocatable_relocs* rr);
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// Emit relocations for a section.
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void
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relocate_relocs(const Relocate_info<32, false>*,
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unsigned int sh_type,
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const unsigned char* prelocs,
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size_t reloc_count,
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Output_section* output_section,
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elfcpp::Elf_types<32>::Elf_Off offset_in_output_section,
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unsigned char* view,
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elfcpp::Elf_types<32>::Elf_Addr view_address,
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section_size_type view_size,
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unsigned char* reloc_view,
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section_size_type reloc_view_size);
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// Return a string used to fill a code section with nops.
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std::string
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do_code_fill(section_size_type length) const;
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// Return whether SYM is defined by the ABI.
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bool
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do_is_defined_by_abi(const Symbol* sym) const
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{ return strcmp(sym->name(), "___tls_get_addr") == 0; }
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// Return whether a symbol name implies a local label. The UnixWare
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// 2.1 cc generates temporary symbols that start with .X, so we
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// recognize them here. FIXME: do other SVR4 compilers also use .X?.
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// If so, we should move the .X recognition into
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// Target::do_is_local_label_name.
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bool
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do_is_local_label_name(const char* name) const
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{
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if (name[0] == '.' && name[1] == 'X')
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return true;
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return Target::do_is_local_label_name(name);
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}
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// Return the PLT address to use for a global symbol.
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uint64_t
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do_plt_address_for_global(const Symbol* gsym) const
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{ return this->plt_section()->address_for_global(gsym); }
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uint64_t
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do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const
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{ return this->plt_section()->address_for_local(relobj, symndx); }
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// We can tell whether we take the address of a function.
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inline bool
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do_can_check_for_function_pointers() const
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{ return true; }
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// Return the base for a DW_EH_PE_datarel encoding.
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uint64_t
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do_ehframe_datarel_base() const;
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// Return whether SYM is call to a non-split function.
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bool
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do_is_call_to_non_split(const Symbol* sym, const unsigned char*,
|
|
const unsigned char*, section_size_type) 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,
|
|
const unsigned char* prelocs, size_t reloc_count,
|
|
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>*, unsigned int,
|
|
Target_i386*, Output_section*, size_t, const unsigned char*,
|
|
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,
|
|
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,
|
|
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 for inquiring about properties of a relocation,
|
|
// used while scanning relocs during a relocatable link and
|
|
// garbage collection.
|
|
class Classify_reloc :
|
|
public gold::Default_classify_reloc<elfcpp::SHT_REL, 32, false>
|
|
{
|
|
public:
|
|
typedef Reloc_types<elfcpp::SHT_REL, 32, false>::Reloc Reltype;
|
|
|
|
// Return the explicit addend of the relocation (return 0 for SHT_REL).
|
|
static elfcpp::Elf_types<32>::Elf_Swxword
|
|
get_r_addend(const Reltype*)
|
|
{ return 0; }
|
|
|
|
// Return the size of the addend of the relocation (only used for SHT_REL).
|
|
static 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)
|
|
{
|
|
unsigned int r_type = elfcpp::elf_r_type<32>(reloc.get_r_info());
|
|
this->copy_relocs_.copy_reloc(symtab, layout,
|
|
symtab->get_sized_symbol<32>(sym),
|
|
object, shndx, output_section,
|
|
r_type, reloc.get_r_offset(), 0,
|
|
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
|
|
32, // hash_entry_size
|
|
};
|
|
|
|
// Get the GOT section, creating it if necessary.
|
|
|
|
Output_data_got<32, false>*
|
|
Target_i386::got_section(Symbol_table* symtab, Layout* layout)
|
|
{
|
|
if (this->got_ == NULL)
|
|
{
|
|
gold_assert(symtab != NULL && layout != NULL);
|
|
|
|
this->got_ = new Output_data_got<32, false>();
|
|
|
|
// 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:
|
|
case elfcpp::R_386_GOT32X:
|
|
// 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:
|
|
case elfcpp::R_386_GOT32X:
|
|
{
|
|
// 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:
|
|
case elfcpp::R_386_GOT32X:
|
|
{
|
|
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:
|
|
case elfcpp::R_386_GOT32X:
|
|
{
|
|
// 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:
|
|
// A GOT-relative reference must resolve locally.
|
|
if (!gsym->is_defined())
|
|
gold_error(_("%s: relocation R_386_GOTOFF against undefined symbol %s"
|
|
" cannot be used when making a shared object"),
|
|
object->name().c_str(), gsym->name());
|
|
else if (gsym->is_from_dynobj())
|
|
gold_error(_("%s: relocation R_386_GOTOFF against external symbol %s"
|
|
" cannot be used when making a shared object"),
|
|
object->name().c_str(), gsym->name());
|
|
else if (gsym->is_preemptible())
|
|
gold_error(_("%s: relocation R_386_GOTOFF against preemptible symbol %s"
|
|
" cannot be used when making a shared object"),
|
|
object->name().c_str(), gsym->name());
|
|
// We need a GOT section.
|
|
target->got_section(symtab, layout);
|
|
break;
|
|
|
|
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, Scan, Classify_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, Scan, Classify_reloc>(
|
|
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,
|
|
unsigned int,
|
|
Target_i386* target,
|
|
Output_section* output_section,
|
|
size_t relnum,
|
|
const unsigned char* preloc,
|
|
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)
|
|
{
|
|
const elfcpp::Rel<32, false> rel(preloc);
|
|
unsigned int r_type = elfcpp::elf_r_type<32>(rel.get_r_info());
|
|
|
|
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;
|
|
}
|
|
}
|
|
|
|
bool baseless;
|
|
|
|
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:
|
|
case elfcpp::R_386_GOT32X:
|
|
baseless = (view[-1] & 0xc7) == 0x5;
|
|
// R_386_GOT32 and R_386_GOT32X don't work without base register
|
|
// when generating a position-independent output file.
|
|
if (baseless
|
|
&& parameters->options().output_is_position_independent())
|
|
{
|
|
if(gsym)
|
|
gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
|
|
_("unexpected reloc %u against global symbol %s without base register in object file when generating a position-independent output file"),
|
|
r_type, gsym->demangled_name().c_str());
|
|
else
|
|
gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
|
|
_("unexpected reloc %u against local symbol without base register in object file when generating a position-independent output file"),
|
|
r_type);
|
|
}
|
|
|
|
// 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);
|
|
// Don't subtract the .got.plt section address for baseless
|
|
// addressing.
|
|
if (!baseless)
|
|
value -= 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());
|
|
}
|
|
// Add the .got.plt section address for baseless addressing.
|
|
if (baseless)
|
|
got_offset += target->got_plt_section()->address();
|
|
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, 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)
|
|
{
|
|
this->tls_desc_gd_to_ie(relinfo, relnum, 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,
|
|
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,
|
|
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, Relocate,
|
|
gold::Default_comdat_behavior, Classify_reloc>(
|
|
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::Classify_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_GOT32X:
|
|
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)
|
|
{
|
|
typedef gold::Default_scan_relocatable_relocs<Classify_reloc>
|
|
Scan_relocatable_relocs;
|
|
|
|
gold_assert(sh_type == elfcpp::SHT_REL);
|
|
|
|
gold::scan_relocatable_relocs<32, false, Scan_relocatable_relocs>(
|
|
symtab,
|
|
layout,
|
|
object,
|
|
data_shndx,
|
|
prelocs,
|
|
reloc_count,
|
|
output_section,
|
|
needs_special_offset_handling,
|
|
local_symbol_count,
|
|
plocal_symbols,
|
|
rr);
|
|
}
|
|
|
|
// Scan the relocs for --emit-relocs.
|
|
|
|
void
|
|
Target_i386::emit_relocs_scan(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_syms,
|
|
Relocatable_relocs* rr)
|
|
{
|
|
typedef gold::Default_classify_reloc<elfcpp::SHT_REL, 32, false>
|
|
Classify_reloc;
|
|
typedef gold::Default_emit_relocs_strategy<Classify_reloc>
|
|
Emit_relocs_strategy;
|
|
|
|
gold_assert(sh_type == elfcpp::SHT_REL);
|
|
|
|
gold::scan_relocatable_relocs<32, false, Emit_relocs_strategy>(
|
|
symtab,
|
|
layout,
|
|
object,
|
|
data_shndx,
|
|
prelocs,
|
|
reloc_count,
|
|
output_section,
|
|
needs_special_offset_handling,
|
|
local_symbol_count,
|
|
plocal_syms,
|
|
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,
|
|
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, Classify_reloc>(
|
|
relinfo,
|
|
prelocs,
|
|
reloc_count,
|
|
output_section,
|
|
offset_in_output_section,
|
|
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,
|
|
const unsigned char*,
|
|
const unsigned char*,
|
|
section_size_type) 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,
|
|
const unsigned char*,
|
|
size_t,
|
|
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
|
|
32, // hash_entry_size
|
|
};
|
|
|
|
#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
|
|
32, // hash_entry_size
|
|
};
|
|
|
|
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.
|