3646 lines
120 KiB
C++
3646 lines
120 KiB
C++
// x86_64.cc -- x86_64 target support for gold.
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// Copyright 2006, 2007, 2008, 2009, 2010 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 "parameters.h"
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#include "reloc.h"
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#include "x86_64.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 "gc.h"
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#include "icf.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 PLT data.
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class Output_data_plt_x86_64 : public Output_section_data
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{
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public:
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typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
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Output_data_plt_x86_64(Symbol_table* symtab, Layout* layout,
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Output_data_got<64, false>* got,
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Output_data_space* got_plt)
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: Output_section_data(8), tlsdesc_rel_(NULL), got_(got), got_plt_(got_plt),
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count_(0), tlsdesc_got_offset_(-1U), free_list_()
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{ this->init(symtab, layout); }
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Output_data_plt_x86_64(Symbol_table* symtab, Layout* layout,
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Output_data_got<64, false>* got,
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Output_data_space* got_plt,
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unsigned int plt_count)
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: Output_section_data((plt_count + 1) * plt_entry_size, 8, false),
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tlsdesc_rel_(NULL), got_(got), got_plt_(got_plt),
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count_(plt_count), tlsdesc_got_offset_(-1U), free_list_()
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{
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this->init(symtab, layout);
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// Initialize the free list and reserve the first entry.
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this->free_list_.init((plt_count + 1) * plt_entry_size, false);
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this->free_list_.remove(0, plt_entry_size);
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}
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// Initialize the PLT section.
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void
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init(Symbol_table* symtab, Layout* layout);
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// Add an entry to the PLT.
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void
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add_entry(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(Sized_relobj_file<64, false>* relobj,
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unsigned int local_sym_index);
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// Add the relocation for a PLT entry.
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void
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add_relocation(Symbol* gsym, unsigned int got_offset);
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// Add the reserved TLSDESC_PLT entry to the PLT.
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void
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reserve_tlsdesc_entry(unsigned int got_offset)
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{ this->tlsdesc_got_offset_ = got_offset; }
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// Return true if a TLSDESC_PLT entry has been reserved.
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bool
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has_tlsdesc_entry() const
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{ return this->tlsdesc_got_offset_ != -1U; }
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// Return the GOT offset for the reserved TLSDESC_PLT entry.
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unsigned int
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get_tlsdesc_got_offset() const
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{ return this->tlsdesc_got_offset_; }
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// Return the offset of the reserved TLSDESC_PLT entry.
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unsigned int
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get_tlsdesc_plt_offset() const
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{ return (this->count_ + 1) * plt_entry_size; }
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// Return the .rela.plt section data.
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Reloc_section*
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rela_plt()
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{ return this->rel_; }
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// Return where the TLSDESC relocations should go.
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Reloc_section*
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rela_tlsdesc(Layout*);
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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_; }
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// Return the offset of the first non-reserved PLT entry.
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static unsigned int
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first_plt_entry_offset()
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{ return plt_entry_size; }
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// Return the size of a PLT entry.
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static unsigned int
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get_plt_entry_size()
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{ return plt_entry_size; }
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// Reserve a slot in the PLT for an existing symbol in an incremental update.
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void
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reserve_slot(unsigned int plt_index)
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{
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this->free_list_.remove((plt_index + 1) * plt_entry_size,
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(plt_index + 2) * plt_entry_size);
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}
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protected:
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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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private:
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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 first entry in the PLT.
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// From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
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// procedure linkage table for both programs and shared objects."
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static 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 unsigned char plt_entry[plt_entry_size];
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// The reserved TLSDESC entry in the PLT for an executable.
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static unsigned char tlsdesc_plt_entry[plt_entry_size];
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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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// Write out the PLT data.
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void
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do_write(Output_file*);
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// The reloc section.
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Reloc_section* rel_;
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// The TLSDESC relocs, if necessary. These must follow the regular
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// PLT relocs.
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Reloc_section* tlsdesc_rel_;
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// The .got section.
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Output_data_got<64, false>* got_;
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// The .got.plt section.
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Output_data_space* got_plt_;
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// The number of PLT entries.
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unsigned int count_;
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// Offset of the reserved TLSDESC_GOT entry when needed.
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unsigned int tlsdesc_got_offset_;
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// List of available regions within the section, for incremental
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// update links.
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Free_list free_list_;
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};
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// The x86_64 target class.
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// See the ABI at
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// http://www.x86-64.org/documentation/abi.pdf
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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_x86_64 : public Target_freebsd<64, false>
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{
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public:
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// In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
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// uses only Elf64_Rela relocation entries with explicit addends."
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typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
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Target_x86_64()
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: Target_freebsd<64, false>(&x86_64_info),
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got_(NULL), plt_(NULL), got_plt_(NULL), got_tlsdesc_(NULL),
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global_offset_table_(NULL), rela_dyn_(NULL),
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copy_relocs_(elfcpp::R_X86_64_COPY), dynbss_(NULL),
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got_mod_index_offset_(-1U), tlsdesc_reloc_info_(),
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tls_base_symbol_defined_(false)
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{ }
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// This function should be defined in targets that can use relocation
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// types to determine (implemented in local_reloc_may_be_function_pointer
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// and global_reloc_may_be_function_pointer)
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// if a function's pointer is taken. ICF uses this in safe mode to only
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// fold those functions whose pointer is defintely not taken. For x86_64
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// pie binaries, safe ICF cannot be done by looking at relocation types.
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inline bool
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can_check_for_function_pointers() const
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{ return !parameters->options().pie(); }
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virtual bool
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can_icf_inline_merge_sections () const
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{ return true; }
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// Hook for a new output section.
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void
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do_new_output_section(Output_section*) const;
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// Scan the relocations to look for symbol adjustments.
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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<64, 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<64, 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<64, 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<64>::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<64, 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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// Relocate a section during a relocatable link.
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void
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relocate_for_relocatable(const Relocate_info<64, 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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off_t offset_in_output_section,
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const Relocatable_relocs*,
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unsigned char* view,
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elfcpp::Elf_types<64>::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 the symbol index to use for a target specific relocation.
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// The only target specific relocation is R_X86_64_TLSDESC for a
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// local symbol, which is an absolute reloc.
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unsigned int
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do_reloc_symbol_index(void*, unsigned int r_type) const
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{
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gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
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return 0;
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}
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// Return the addend to use for a target specific relocation.
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uint64_t
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do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const;
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// Return the PLT section.
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Output_data*
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do_plt_section_for_global(const Symbol*) const
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{ return this->plt_section(); }
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Output_data*
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do_plt_section_for_local(const Relobj*, unsigned int) const
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{ return this->plt_section(); }
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// Adjust -fsplit-stack code which calls non-split-stack code.
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void
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do_calls_non_split(Relobj* object, unsigned int shndx,
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section_offset_type fnoffset, section_size_type fnsize,
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unsigned char* view, section_size_type view_size,
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std::string* from, std::string* to) const;
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// Return the size of the GOT section.
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section_size_type
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got_size() const
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{
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gold_assert(this->got_ != NULL);
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return this->got_->data_size();
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}
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// Return the number of entries in the GOT.
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unsigned int
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got_entry_count() const
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{
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if (this->got_ == NULL)
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return 0;
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return this->got_size() / 8;
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}
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// Return the number of entries in the PLT.
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unsigned int
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plt_entry_count() const;
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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() const;
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// Return the size of each PLT entry.
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unsigned int
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plt_entry_size() const;
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// Create the GOT section for an incremental update.
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Output_data_got<64, false>*
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init_got_plt_for_update(Symbol_table* symtab,
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Layout* layout,
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unsigned int got_count,
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unsigned int plt_count);
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// Reserve a GOT entry for a local symbol, and regenerate any
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// necessary dynamic relocations.
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void
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reserve_local_got_entry(unsigned int got_index,
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Sized_relobj<64, false>* obj,
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unsigned int r_sym,
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unsigned int got_type);
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// Reserve a GOT entry for a global symbol, and regenerate any
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// necessary dynamic relocations.
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void
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reserve_global_got_entry(unsigned int got_index, Symbol* gsym,
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unsigned int got_type);
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// Register an existing PLT entry for a global symbol.
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void
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register_global_plt_entry(unsigned int plt_index, Symbol* gsym);
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// Force a COPY relocation for a given symbol.
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void
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emit_copy_reloc(Symbol_table*, Symbol*, Output_section*, off_t);
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// Apply an incremental relocation.
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void
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apply_relocation(const Relocate_info<64, false>* relinfo,
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elfcpp::Elf_types<64>::Elf_Addr r_offset,
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unsigned int r_type,
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elfcpp::Elf_types<64>::Elf_Swxword r_addend,
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const Symbol* gsym,
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unsigned char* view,
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elfcpp::Elf_types<64>::Elf_Addr address,
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section_size_type view_size);
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// Add a new reloc argument, returning the index in the vector.
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size_t
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add_tlsdesc_info(Sized_relobj_file<64, false>* object, unsigned int r_sym)
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{
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this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym));
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return this->tlsdesc_reloc_info_.size() - 1;
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}
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private:
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// The class which scans relocations.
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class Scan
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{
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public:
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Scan()
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: issued_non_pic_error_(false)
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{ }
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static inline int
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get_reference_flags(unsigned int r_type);
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inline void
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local(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
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Sized_relobj_file<64, false>* object,
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unsigned int data_shndx,
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Output_section* output_section,
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const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
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const elfcpp::Sym<64, false>& lsym);
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inline void
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global(Symbol_table* symtab, Layout* layout, Target_x86_64* target,
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Sized_relobj_file<64, false>* object,
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unsigned int data_shndx,
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Output_section* output_section,
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const elfcpp::Rela<64, false>& reloc, unsigned int r_type,
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Symbol* gsym);
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inline bool
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local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
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Target_x86_64* target,
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Sized_relobj_file<64, false>* object,
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unsigned int data_shndx,
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Output_section* output_section,
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const elfcpp::Rela<64, false>& reloc,
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unsigned int r_type,
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const elfcpp::Sym<64, false>& lsym);
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inline bool
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global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
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Target_x86_64* target,
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Sized_relobj_file<64, false>* object,
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unsigned int data_shndx,
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Output_section* output_section,
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const elfcpp::Rela<64, false>& reloc,
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unsigned int r_type,
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Symbol* gsym);
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private:
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static void
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unsupported_reloc_local(Sized_relobj_file<64, false>*, unsigned int r_type);
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static void
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unsupported_reloc_global(Sized_relobj_file<64, false>*, unsigned int r_type,
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Symbol*);
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void
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check_non_pic(Relobj*, unsigned int r_type);
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inline bool
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possible_function_pointer_reloc(unsigned int r_type);
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bool
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reloc_needs_plt_for_ifunc(Sized_relobj_file<64, false>*,
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unsigned int r_type);
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// Whether we have issued an error about a non-PIC compilation.
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bool issued_non_pic_error_;
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};
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// The class which implements relocation.
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class Relocate
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{
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public:
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Relocate()
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: skip_call_tls_get_addr_(false)
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{ }
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~Relocate()
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{
|
|
if (this->skip_call_tls_get_addr_)
|
|
{
|
|
// FIXME: This needs to specify the location somehow.
|
|
gold_error(_("missing expected TLS relocation"));
|
|
}
|
|
}
|
|
|
|
// Do a relocation. Return false if the caller should not issue
|
|
// any warnings about this relocation.
|
|
inline bool
|
|
relocate(const Relocate_info<64, false>*, Target_x86_64*, Output_section*,
|
|
size_t relnum, const elfcpp::Rela<64, false>&,
|
|
unsigned int r_type, const Sized_symbol<64>*,
|
|
const Symbol_value<64>*,
|
|
unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
|
|
section_size_type);
|
|
|
|
private:
|
|
// Do a TLS relocation.
|
|
inline void
|
|
relocate_tls(const Relocate_info<64, false>*, Target_x86_64*,
|
|
size_t relnum, const elfcpp::Rela<64, false>&,
|
|
unsigned int r_type, const Sized_symbol<64>*,
|
|
const Symbol_value<64>*,
|
|
unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
|
|
section_size_type);
|
|
|
|
// Do a TLS General-Dynamic to Initial-Exec transition.
|
|
inline void
|
|
tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
|
|
Output_segment* tls_segment,
|
|
const elfcpp::Rela<64, false>&, unsigned int r_type,
|
|
elfcpp::Elf_types<64>::Elf_Addr value,
|
|
unsigned char* view,
|
|
elfcpp::Elf_types<64>::Elf_Addr,
|
|
section_size_type view_size);
|
|
|
|
// Do a TLS General-Dynamic to Local-Exec transition.
|
|
inline void
|
|
tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
|
|
Output_segment* tls_segment,
|
|
const elfcpp::Rela<64, false>&, unsigned int r_type,
|
|
elfcpp::Elf_types<64>::Elf_Addr value,
|
|
unsigned char* view,
|
|
section_size_type view_size);
|
|
|
|
// Do a TLSDESC-style General-Dynamic to Initial-Exec transition.
|
|
inline void
|
|
tls_desc_gd_to_ie(const Relocate_info<64, false>*, size_t relnum,
|
|
Output_segment* tls_segment,
|
|
const elfcpp::Rela<64, false>&, unsigned int r_type,
|
|
elfcpp::Elf_types<64>::Elf_Addr value,
|
|
unsigned char* view,
|
|
elfcpp::Elf_types<64>::Elf_Addr,
|
|
section_size_type view_size);
|
|
|
|
// Do a TLSDESC-style General-Dynamic to Local-Exec transition.
|
|
inline void
|
|
tls_desc_gd_to_le(const Relocate_info<64, false>*, size_t relnum,
|
|
Output_segment* tls_segment,
|
|
const elfcpp::Rela<64, false>&, unsigned int r_type,
|
|
elfcpp::Elf_types<64>::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<64, false>*, size_t relnum,
|
|
Output_segment* tls_segment,
|
|
const elfcpp::Rela<64, false>&, unsigned int r_type,
|
|
elfcpp::Elf_types<64>::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<64, false>*, size_t relnum,
|
|
Output_segment* tls_segment,
|
|
const elfcpp::Rela<64, false>&, unsigned int r_type,
|
|
elfcpp::Elf_types<64>::Elf_Addr value,
|
|
unsigned char* view,
|
|
section_size_type view_size);
|
|
|
|
// 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_;
|
|
};
|
|
|
|
// A class which returns the size required for a relocation type,
|
|
// used while scanning relocs during a relocatable link.
|
|
class Relocatable_size_for_reloc
|
|
{
|
|
public:
|
|
unsigned int
|
|
get_size_for_reloc(unsigned int, Relobj*);
|
|
};
|
|
|
|
// Adjust TLS relocation type based on the options and whether this
|
|
// is a local symbol.
|
|
static tls::Tls_optimization
|
|
optimize_tls_reloc(bool is_final, int r_type);
|
|
|
|
// Get the GOT section, creating it if necessary.
|
|
Output_data_got<64, false>*
|
|
got_section(Symbol_table*, Layout*);
|
|
|
|
// Get the GOT PLT section.
|
|
Output_data_space*
|
|
got_plt_section() const
|
|
{
|
|
gold_assert(this->got_plt_ != NULL);
|
|
return this->got_plt_;
|
|
}
|
|
|
|
// Get the GOT section for TLSDESC entries.
|
|
Output_data_got<64, 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<64, 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 the reserved PLT and GOT entries for the TLS descriptor resolver.
|
|
void
|
|
reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
|
|
|
|
// Create a GOT entry for the TLS module index.
|
|
unsigned int
|
|
got_mod_index_entry(Symbol_table* symtab, Layout* layout,
|
|
Sized_relobj_file<64, false>* object);
|
|
|
|
// Get the PLT section.
|
|
Output_data_plt_x86_64*
|
|
plt_section() const
|
|
{
|
|
gold_assert(this->plt_ != NULL);
|
|
return this->plt_;
|
|
}
|
|
|
|
// Get the dynamic reloc section, creating it if necessary.
|
|
Reloc_section*
|
|
rela_dyn_section(Layout*);
|
|
|
|
// Get the section to use for TLSDESC relocations.
|
|
Reloc_section*
|
|
rela_tlsdesc_section(Layout*) const;
|
|
|
|
// Add a potential copy relocation.
|
|
void
|
|
copy_reloc(Symbol_table* symtab, Layout* layout,
|
|
Sized_relobj_file<64, false>* object,
|
|
unsigned int shndx, Output_section* output_section,
|
|
Symbol* sym, const elfcpp::Rela<64, false>& reloc)
|
|
{
|
|
this->copy_relocs_.copy_reloc(symtab, layout,
|
|
symtab->get_sized_symbol<64>(sym),
|
|
object, shndx, output_section,
|
|
reloc, this->rela_dyn_section(layout));
|
|
}
|
|
|
|
// Information about this specific target which we pass to the
|
|
// general Target structure.
|
|
static const Target::Target_info x86_64_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_OFFSET = 1, // GOT entry for TLS offset
|
|
GOT_TYPE_TLS_PAIR = 2, // GOT entry for TLS module/offset pair
|
|
GOT_TYPE_TLS_DESC = 3 // GOT entry for TLS_DESC pair
|
|
};
|
|
|
|
// This type is used as the argument to the target specific
|
|
// relocation routines. The only target specific reloc is
|
|
// R_X86_64_TLSDESC against a local symbol.
|
|
struct Tlsdesc_info
|
|
{
|
|
Tlsdesc_info(Sized_relobj_file<64, false>* a_object, unsigned int a_r_sym)
|
|
: object(a_object), r_sym(a_r_sym)
|
|
{ }
|
|
|
|
// The object in which the local symbol is defined.
|
|
Sized_relobj_file<64, false>* object;
|
|
// The local symbol index in the object.
|
|
unsigned int r_sym;
|
|
};
|
|
|
|
// The GOT section.
|
|
Output_data_got<64, false>* got_;
|
|
// The PLT section.
|
|
Output_data_plt_x86_64* plt_;
|
|
// The GOT PLT section.
|
|
Output_data_space* got_plt_;
|
|
// The GOT section for TLSDESC relocations.
|
|
Output_data_got<64, false>* got_tlsdesc_;
|
|
// The _GLOBAL_OFFSET_TABLE_ symbol.
|
|
Symbol* global_offset_table_;
|
|
// The dynamic reloc section.
|
|
Reloc_section* rela_dyn_;
|
|
// Relocs saved to avoid a COPY reloc.
|
|
Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_;
|
|
// Space for variables copied with a COPY reloc.
|
|
Output_data_space* dynbss_;
|
|
// Offset of the GOT entry for the TLS module index.
|
|
unsigned int got_mod_index_offset_;
|
|
// We handle R_X86_64_TLSDESC against a local symbol as a target
|
|
// specific relocation. Here we store the object and local symbol
|
|
// index for the relocation.
|
|
std::vector<Tlsdesc_info> tlsdesc_reloc_info_;
|
|
// True if the _TLS_MODULE_BASE_ symbol has been defined.
|
|
bool tls_base_symbol_defined_;
|
|
};
|
|
|
|
const Target::Target_info Target_x86_64::x86_64_info =
|
|
{
|
|
64, // size
|
|
false, // is_big_endian
|
|
elfcpp::EM_X86_64, // machine_code
|
|
false, // has_make_symbol
|
|
false, // has_resolve
|
|
true, // has_code_fill
|
|
true, // is_default_stack_executable
|
|
'\0', // wrap_char
|
|
"/lib/ld64.so.1", // program interpreter
|
|
0x400000, // default_text_segment_address
|
|
0x1000, // abi_pagesize (overridable by -z max-page-size)
|
|
0x1000, // common_pagesize (overridable by -z common-page-size)
|
|
elfcpp::SHN_UNDEF, // small_common_shndx
|
|
elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx
|
|
0, // small_common_section_flags
|
|
elfcpp::SHF_X86_64_LARGE, // large_common_section_flags
|
|
NULL, // attributes_section
|
|
NULL // attributes_vendor
|
|
};
|
|
|
|
// This is called when a new output section is created. This is where
|
|
// we handle the SHF_X86_64_LARGE.
|
|
|
|
void
|
|
Target_x86_64::do_new_output_section(Output_section* os) const
|
|
{
|
|
if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0)
|
|
os->set_is_large_section();
|
|
}
|
|
|
|
// Get the GOT section, creating it if necessary.
|
|
|
|
Output_data_got<64, false>*
|
|
Target_x86_64::got_section(Symbol_table* symtab, Layout* layout)
|
|
{
|
|
if (this->got_ == NULL)
|
|
{
|
|
gold_assert(symtab != NULL && layout != NULL);
|
|
|
|
this->got_ = new Output_data_got<64, false>();
|
|
|
|
layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
|
|
(elfcpp::SHF_ALLOC
|
|
| elfcpp::SHF_WRITE),
|
|
this->got_, ORDER_RELRO_LAST,
|
|
true);
|
|
|
|
this->got_plt_ = new Output_data_space(8, "** GOT PLT");
|
|
layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
|
|
(elfcpp::SHF_ALLOC
|
|
| elfcpp::SHF_WRITE),
|
|
this->got_plt_, ORDER_NON_RELRO_FIRST,
|
|
false);
|
|
|
|
// The first three entries are reserved.
|
|
this->got_plt_->set_current_data_size(3 * 8);
|
|
|
|
// Those bytes can go into the relro segment.
|
|
layout->increase_relro(3 * 8);
|
|
|
|
// 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 TLSDESC relocations, they get GOT entries in
|
|
// .got.plt after the jump slot entries.
|
|
this->got_tlsdesc_ = new Output_data_got<64, false>();
|
|
layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
|
|
(elfcpp::SHF_ALLOC
|
|
| elfcpp::SHF_WRITE),
|
|
this->got_tlsdesc_,
|
|
ORDER_NON_RELRO_FIRST, false);
|
|
}
|
|
|
|
return this->got_;
|
|
}
|
|
|
|
// Get the dynamic reloc section, creating it if necessary.
|
|
|
|
Target_x86_64::Reloc_section*
|
|
Target_x86_64::rela_dyn_section(Layout* layout)
|
|
{
|
|
if (this->rela_dyn_ == NULL)
|
|
{
|
|
gold_assert(layout != NULL);
|
|
this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
|
|
layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
|
|
elfcpp::SHF_ALLOC, this->rela_dyn_,
|
|
ORDER_DYNAMIC_RELOCS, false);
|
|
}
|
|
return this->rela_dyn_;
|
|
}
|
|
|
|
// Initialize the PLT section.
|
|
|
|
void
|
|
Output_data_plt_x86_64::init(Symbol_table* symtab, Layout* layout)
|
|
{
|
|
this->rel_ = new Reloc_section(false);
|
|
layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
|
|
elfcpp::SHF_ALLOC, this->rel_,
|
|
ORDER_DYNAMIC_PLT_RELOCS, false);
|
|
|
|
if (parameters->doing_static_link())
|
|
{
|
|
// A statically linked executable will only have a .rela.plt
|
|
// section to hold R_X86_64_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("__rela_iplt_start", NULL,
|
|
Symbol_table::PREDEFINED,
|
|
this->rel_, 0, 0, elfcpp::STT_NOTYPE,
|
|
elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN,
|
|
0, false, true);
|
|
symtab->define_in_output_data("__rela_iplt_end", NULL,
|
|
Symbol_table::PREDEFINED,
|
|
this->rel_, 0, 0, elfcpp::STT_NOTYPE,
|
|
elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN,
|
|
0, true, true);
|
|
}
|
|
}
|
|
|
|
void
|
|
Output_data_plt_x86_64::do_adjust_output_section(Output_section* os)
|
|
{
|
|
os->set_entsize(plt_entry_size);
|
|
}
|
|
|
|
// Add an entry to the PLT.
|
|
|
|
void
|
|
Output_data_plt_x86_64::add_entry(Symbol* gsym)
|
|
{
|
|
gold_assert(!gsym->has_plt_offset());
|
|
|
|
unsigned int plt_index;
|
|
off_t plt_offset;
|
|
section_offset_type got_offset;
|
|
|
|
if (!this->is_data_size_valid())
|
|
{
|
|
// Note that when setting the PLT offset we skip the initial
|
|
// reserved PLT entry.
|
|
plt_index = this->count_ + 1;
|
|
plt_offset = plt_index * plt_entry_size;
|
|
|
|
++this->count_;
|
|
|
|
got_offset = (plt_index - 1 + 3) * 8;
|
|
gold_assert(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 + 8);
|
|
}
|
|
else
|
|
{
|
|
// For incremental updates, find an available slot.
|
|
plt_offset = this->free_list_.allocate(plt_entry_size, plt_entry_size, 0);
|
|
if (plt_offset == -1)
|
|
gold_fallback(_("out of patch space (PLT);"
|
|
" relink with --incremental-full"));
|
|
|
|
// The GOT and PLT entries have a 1-1 correspondance, so the GOT offset
|
|
// can be calculated from the PLT index, adjusting for the three
|
|
// reserved entries at the beginning of the GOT.
|
|
plt_index = plt_offset / plt_entry_size - 1;
|
|
got_offset = (plt_index - 1 + 3) * 8;
|
|
}
|
|
|
|
gsym->set_plt_offset(plt_offset);
|
|
|
|
// Every PLT entry needs a reloc.
|
|
this->add_relocation(gsym, 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_x86_64::add_local_ifunc_entry(
|
|
Sized_relobj_file<64, false>* relobj,
|
|
unsigned int local_sym_index)
|
|
{
|
|
unsigned int plt_offset = (this->count_ + 1) * plt_entry_size;
|
|
++this->count_;
|
|
|
|
section_offset_type got_offset = this->got_plt_->current_data_size();
|
|
|
|
// Every PLT entry needs a GOT entry which points back to the PLT
|
|
// entry.
|
|
this->got_plt_->set_current_data_size(got_offset + 8);
|
|
|
|
// Every PLT entry needs a reloc.
|
|
this->rel_->add_symbolless_local_addend(relobj, local_sym_index,
|
|
elfcpp::R_X86_64_IRELATIVE,
|
|
this->got_plt_, got_offset, 0);
|
|
|
|
return plt_offset;
|
|
}
|
|
|
|
// Add the relocation for a PLT entry.
|
|
|
|
void
|
|
Output_data_plt_x86_64::add_relocation(Symbol* gsym, unsigned int got_offset)
|
|
{
|
|
if (gsym->type() == elfcpp::STT_GNU_IFUNC
|
|
&& gsym->can_use_relative_reloc(false))
|
|
this->rel_->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE,
|
|
this->got_plt_, got_offset, 0);
|
|
else
|
|
{
|
|
gsym->set_needs_dynsym_entry();
|
|
this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_,
|
|
got_offset, 0);
|
|
}
|
|
}
|
|
|
|
// Return where the TLSDESC relocations should go, creating it if
|
|
// necessary. These follow the JUMP_SLOT relocations.
|
|
|
|
Output_data_plt_x86_64::Reloc_section*
|
|
Output_data_plt_x86_64::rela_tlsdesc(Layout* layout)
|
|
{
|
|
if (this->tlsdesc_rel_ == NULL)
|
|
{
|
|
this->tlsdesc_rel_ = new Reloc_section(false);
|
|
layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
|
|
elfcpp::SHF_ALLOC, this->tlsdesc_rel_,
|
|
ORDER_DYNAMIC_PLT_RELOCS, false);
|
|
gold_assert(this->tlsdesc_rel_->output_section() ==
|
|
this->rel_->output_section());
|
|
}
|
|
return this->tlsdesc_rel_;
|
|
}
|
|
|
|
// Set the final size.
|
|
void
|
|
Output_data_plt_x86_64::set_final_data_size()
|
|
{
|
|
unsigned int count = this->count_;
|
|
if (this->has_tlsdesc_entry())
|
|
++count;
|
|
this->set_data_size((count + 1) * plt_entry_size);
|
|
}
|
|
|
|
// The first entry in the PLT for an executable.
|
|
|
|
unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
|
|
{
|
|
// From AMD64 ABI Draft 0.98, page 76
|
|
0xff, 0x35, // pushq contents of memory address
|
|
0, 0, 0, 0, // replaced with address of .got + 8
|
|
0xff, 0x25, // jmp indirect
|
|
0, 0, 0, 0, // replaced with address of .got + 16
|
|
0x90, 0x90, 0x90, 0x90 // noop (x4)
|
|
};
|
|
|
|
// Subsequent entries in the PLT for an executable.
|
|
|
|
unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
|
|
{
|
|
// From AMD64 ABI Draft 0.98, page 76
|
|
0xff, 0x25, // jmpq indirect
|
|
0, 0, 0, 0, // replaced with address of symbol in .got
|
|
0x68, // pushq immediate
|
|
0, 0, 0, 0, // replaced with offset into relocation table
|
|
0xe9, // jmpq relative
|
|
0, 0, 0, 0 // replaced with offset to start of .plt
|
|
};
|
|
|
|
// The reserved TLSDESC entry in the PLT for an executable.
|
|
|
|
unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] =
|
|
{
|
|
// From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
|
|
// and AMD64/EM64T", Version 0.9.4 (2005-10-10).
|
|
0xff, 0x35, // pushq x(%rip)
|
|
0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8)
|
|
0xff, 0x25, // jmpq *y(%rip)
|
|
0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry
|
|
0x0f, 0x1f, // nop
|
|
0x40, 0
|
|
};
|
|
|
|
// Write out the PLT. This uses the hand-coded instructions above,
|
|
// and adjusts them as needed. This is specified by the AMD64 ABI.
|
|
|
|
void
|
|
Output_data_plt_x86_64::do_write(Output_file* of)
|
|
{
|
|
const off_t offset = this->offset();
|
|
const section_size_type oview_size =
|
|
convert_to_section_size_type(this->data_size());
|
|
unsigned char* const oview = of->get_output_view(offset, oview_size);
|
|
|
|
const off_t got_file_offset = this->got_plt_->offset();
|
|
const section_size_type got_size =
|
|
convert_to_section_size_type(this->got_plt_->data_size());
|
|
unsigned char* const got_view = of->get_output_view(got_file_offset,
|
|
got_size);
|
|
|
|
unsigned char* pov = oview;
|
|
|
|
// The base address of the .plt section.
|
|
elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address();
|
|
// The base address of the .got section.
|
|
elfcpp::Elf_types<64>::Elf_Addr got_base = this->got_->address();
|
|
// The base address of the PLT portion of the .got section,
|
|
// which is where the GOT pointer will point, and where the
|
|
// three reserved GOT entries are located.
|
|
elfcpp::Elf_types<64>::Elf_Addr got_address = this->got_plt_->address();
|
|
|
|
memcpy(pov, first_plt_entry, plt_entry_size);
|
|
// We do a jmp relative to the PC at the end of this instruction.
|
|
elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
|
|
(got_address + 8
|
|
- (plt_address + 6)));
|
|
elfcpp::Swap<32, false>::writeval(pov + 8,
|
|
(got_address + 16
|
|
- (plt_address + 12)));
|
|
pov += plt_entry_size;
|
|
|
|
unsigned char* got_pov = got_view;
|
|
|
|
memset(got_pov, 0, 24);
|
|
got_pov += 24;
|
|
|
|
unsigned int plt_offset = plt_entry_size;
|
|
unsigned int got_offset = 24;
|
|
const unsigned int count = this->count_;
|
|
for (unsigned int plt_index = 0;
|
|
plt_index < count;
|
|
++plt_index,
|
|
pov += plt_entry_size,
|
|
got_pov += 8,
|
|
plt_offset += plt_entry_size,
|
|
got_offset += 8)
|
|
{
|
|
// Set and adjust the PLT entry itself.
|
|
memcpy(pov, plt_entry, plt_entry_size);
|
|
elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
|
|
(got_address + got_offset
|
|
- (plt_address + plt_offset
|
|
+ 6)));
|
|
|
|
elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
|
|
elfcpp::Swap<32, false>::writeval(pov + 12,
|
|
- (plt_offset + plt_entry_size));
|
|
|
|
// Set the entry in the GOT.
|
|
elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6);
|
|
}
|
|
|
|
if (this->has_tlsdesc_entry())
|
|
{
|
|
// Set and adjust the reserved TLSDESC PLT entry.
|
|
unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset();
|
|
memcpy(pov, tlsdesc_plt_entry, plt_entry_size);
|
|
elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
|
|
(got_address + 8
|
|
- (plt_address + plt_offset
|
|
+ 6)));
|
|
elfcpp::Swap_unaligned<32, false>::writeval(pov + 8,
|
|
(got_base
|
|
+ tlsdesc_got_offset
|
|
- (plt_address + plt_offset
|
|
+ 12)));
|
|
pov += plt_entry_size;
|
|
}
|
|
|
|
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_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout)
|
|
{
|
|
if (this->plt_ == NULL)
|
|
{
|
|
// Create the GOT sections first.
|
|
this->got_section(symtab, layout);
|
|
|
|
this->plt_ = new Output_data_plt_x86_64(symtab, layout, this->got_,
|
|
this->got_plt_);
|
|
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 .rela.plt point to .plt.
|
|
Output_section* rela_plt_os = this->plt_->rela_plt()->output_section();
|
|
rela_plt_os->set_info_section(this->plt_->output_section());
|
|
}
|
|
}
|
|
|
|
// Return the section for TLSDESC relocations.
|
|
|
|
Target_x86_64::Reloc_section*
|
|
Target_x86_64::rela_tlsdesc_section(Layout* layout) const
|
|
{
|
|
return this->plt_section()->rela_tlsdesc(layout);
|
|
}
|
|
|
|
// Create a PLT entry for a global symbol.
|
|
|
|
void
|
|
Target_x86_64::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(gsym);
|
|
}
|
|
|
|
// Make a PLT entry for a local STT_GNU_IFUNC symbol.
|
|
|
|
void
|
|
Target_x86_64::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout,
|
|
Sized_relobj_file<64, 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(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_x86_64::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_x86_64::first_plt_entry_offset() const
|
|
{
|
|
return Output_data_plt_x86_64::first_plt_entry_offset();
|
|
}
|
|
|
|
// Return the size of each PLT entry.
|
|
|
|
unsigned int
|
|
Target_x86_64::plt_entry_size() const
|
|
{
|
|
return Output_data_plt_x86_64::get_plt_entry_size();
|
|
}
|
|
|
|
// Create the GOT and PLT sections for an incremental update.
|
|
|
|
Output_data_got<64, false>*
|
|
Target_x86_64::init_got_plt_for_update(Symbol_table* symtab,
|
|
Layout* layout,
|
|
unsigned int got_count,
|
|
unsigned int plt_count)
|
|
{
|
|
gold_assert(this->got_ == NULL);
|
|
|
|
this->got_ = new Output_data_got<64, false>(got_count * 8);
|
|
layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
|
|
(elfcpp::SHF_ALLOC
|
|
| elfcpp::SHF_WRITE),
|
|
this->got_, ORDER_RELRO_LAST,
|
|
true);
|
|
|
|
// Add the three reserved entries.
|
|
this->got_plt_ = new Output_data_space((plt_count + 3) * 8, 8, "** GOT PLT");
|
|
layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
|
|
(elfcpp::SHF_ALLOC
|
|
| elfcpp::SHF_WRITE),
|
|
this->got_plt_, ORDER_NON_RELRO_FIRST,
|
|
false);
|
|
|
|
// 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 TLSDESC relocations, they get GOT entries in
|
|
// .got.plt after the jump slot entries.
|
|
// FIXME: Get the count for TLSDESC entries.
|
|
this->got_tlsdesc_ = new Output_data_got<64, false>(0);
|
|
layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
|
|
elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
|
|
this->got_tlsdesc_,
|
|
ORDER_NON_RELRO_FIRST, false);
|
|
|
|
// Create the PLT section.
|
|
this->plt_ = new Output_data_plt_x86_64(symtab, layout, this->got_,
|
|
this->got_plt_, plt_count);
|
|
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 .rela.plt point to .plt.
|
|
Output_section* rela_plt_os = this->plt_->rela_plt()->output_section();
|
|
rela_plt_os->set_info_section(this->plt_->output_section());
|
|
|
|
// Create the rela_dyn section.
|
|
this->rela_dyn_section(layout);
|
|
|
|
return this->got_;
|
|
}
|
|
|
|
// Reserve a GOT entry for a local symbol, and regenerate any
|
|
// necessary dynamic relocations.
|
|
|
|
void
|
|
Target_x86_64::reserve_local_got_entry(
|
|
unsigned int got_index,
|
|
Sized_relobj<64, false>* obj,
|
|
unsigned int r_sym,
|
|
unsigned int got_type)
|
|
{
|
|
unsigned int got_offset = got_index * 8;
|
|
Reloc_section* rela_dyn = this->rela_dyn_section(NULL);
|
|
|
|
this->got_->reserve_local(got_index, obj, r_sym, got_type);
|
|
switch (got_type)
|
|
{
|
|
case GOT_TYPE_STANDARD:
|
|
if (parameters->options().output_is_position_independent())
|
|
rela_dyn->add_local_relative(obj, r_sym, elfcpp::R_X86_64_RELATIVE,
|
|
this->got_, got_offset, 0);
|
|
break;
|
|
case GOT_TYPE_TLS_OFFSET:
|
|
rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_TPOFF64,
|
|
this->got_, got_offset, 0);
|
|
break;
|
|
case GOT_TYPE_TLS_PAIR:
|
|
this->got_->reserve_slot(got_index + 1);
|
|
rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_DTPMOD64,
|
|
this->got_, got_offset, 0);
|
|
break;
|
|
case GOT_TYPE_TLS_DESC:
|
|
gold_fatal(_("TLS_DESC not yet supported for incremental linking"));
|
|
// this->got_->reserve_slot(got_index + 1);
|
|
// rela_dyn->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
|
|
// this->got_, got_offset, 0);
|
|
break;
|
|
default:
|
|
gold_unreachable();
|
|
}
|
|
}
|
|
|
|
// Reserve a GOT entry for a global symbol, and regenerate any
|
|
// necessary dynamic relocations.
|
|
|
|
void
|
|
Target_x86_64::reserve_global_got_entry(unsigned int got_index, Symbol* gsym,
|
|
unsigned int got_type)
|
|
{
|
|
unsigned int got_offset = got_index * 8;
|
|
Reloc_section* rela_dyn = this->rela_dyn_section(NULL);
|
|
|
|
this->got_->reserve_global(got_index, gsym, got_type);
|
|
switch (got_type)
|
|
{
|
|
case GOT_TYPE_STANDARD:
|
|
if (!gsym->final_value_is_known())
|
|
{
|
|
if (gsym->is_from_dynobj()
|
|
|| gsym->is_undefined()
|
|
|| gsym->is_preemptible()
|
|
|| gsym->type() == elfcpp::STT_GNU_IFUNC)
|
|
rela_dyn->add_global(gsym, elfcpp::R_X86_64_GLOB_DAT,
|
|
this->got_, got_offset, 0);
|
|
else
|
|
rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
|
|
this->got_, got_offset, 0);
|
|
}
|
|
break;
|
|
case GOT_TYPE_TLS_OFFSET:
|
|
rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TPOFF64,
|
|
this->got_, got_offset, 0);
|
|
break;
|
|
case GOT_TYPE_TLS_PAIR:
|
|
this->got_->reserve_slot(got_index + 1);
|
|
rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPMOD64,
|
|
this->got_, got_offset, 0);
|
|
rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPOFF64,
|
|
this->got_, got_offset + 8, 0);
|
|
break;
|
|
case GOT_TYPE_TLS_DESC:
|
|
this->got_->reserve_slot(got_index + 1);
|
|
rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TLSDESC,
|
|
this->got_, got_offset, 0);
|
|
break;
|
|
default:
|
|
gold_unreachable();
|
|
}
|
|
}
|
|
|
|
// Register an existing PLT entry for a global symbol.
|
|
|
|
void
|
|
Target_x86_64::register_global_plt_entry(unsigned int plt_index,
|
|
Symbol* gsym)
|
|
{
|
|
gold_assert(this->plt_ != NULL);
|
|
gold_assert(!gsym->has_plt_offset());
|
|
|
|
this->plt_->reserve_slot(plt_index);
|
|
|
|
gsym->set_plt_offset((plt_index + 1) * this->plt_entry_size());
|
|
|
|
unsigned int got_offset = (plt_index + 3) * 8;
|
|
this->plt_->add_relocation(gsym, got_offset);
|
|
}
|
|
|
|
// Force a COPY relocation for a given symbol.
|
|
|
|
void
|
|
Target_x86_64::emit_copy_reloc(
|
|
Symbol_table* symtab, Symbol* sym, Output_section* os, off_t offset)
|
|
{
|
|
this->copy_relocs_.emit_copy_reloc(symtab,
|
|
symtab->get_sized_symbol<64>(sym),
|
|
os,
|
|
offset,
|
|
this->rela_dyn_section(NULL));
|
|
}
|
|
|
|
// Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
|
|
|
|
void
|
|
Target_x86_64::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 the reserved PLT and GOT entries for the TLS descriptor resolver.
|
|
|
|
void
|
|
Target_x86_64::reserve_tlsdesc_entries(Symbol_table* symtab,
|
|
Layout* layout)
|
|
{
|
|
if (this->plt_ == NULL)
|
|
this->make_plt_section(symtab, layout);
|
|
|
|
if (!this->plt_->has_tlsdesc_entry())
|
|
{
|
|
// Allocate the TLSDESC_GOT entry.
|
|
Output_data_got<64, false>* got = this->got_section(symtab, layout);
|
|
unsigned int got_offset = got->add_constant(0);
|
|
|
|
// Allocate the TLSDESC_PLT entry.
|
|
this->plt_->reserve_tlsdesc_entry(got_offset);
|
|
}
|
|
}
|
|
|
|
// Create a GOT entry for the TLS module index.
|
|
|
|
unsigned int
|
|
Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
|
|
Sized_relobj_file<64, false>* object)
|
|
{
|
|
if (this->got_mod_index_offset_ == -1U)
|
|
{
|
|
gold_assert(symtab != NULL && layout != NULL && object != NULL);
|
|
Reloc_section* rela_dyn = this->rela_dyn_section(layout);
|
|
Output_data_got<64, false>* got = this->got_section(symtab, layout);
|
|
unsigned int got_offset = got->add_constant(0);
|
|
rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
|
|
got_offset, 0);
|
|
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_x86_64::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_X86_64_TLSGD:
|
|
case elfcpp::R_X86_64_GOTPC32_TLSDESC:
|
|
case elfcpp::R_X86_64_TLSDESC_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_X86_64_TLSLD:
|
|
// 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_X86_64_DTPOFF32:
|
|
case elfcpp::R_X86_64_DTPOFF64:
|
|
// Another Local-Dynamic reloc.
|
|
return tls::TLSOPT_TO_LE;
|
|
|
|
case elfcpp::R_X86_64_GOTTPOFF:
|
|
// 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_X86_64_TPOFF32:
|
|
// 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_x86_64::Scan::get_reference_flags(unsigned int r_type)
|
|
{
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_X86_64_NONE:
|
|
case elfcpp::R_X86_64_GNU_VTINHERIT:
|
|
case elfcpp::R_X86_64_GNU_VTENTRY:
|
|
case elfcpp::R_X86_64_GOTPC32:
|
|
case elfcpp::R_X86_64_GOTPC64:
|
|
// No symbol reference.
|
|
return 0;
|
|
|
|
case elfcpp::R_X86_64_64:
|
|
case elfcpp::R_X86_64_32:
|
|
case elfcpp::R_X86_64_32S:
|
|
case elfcpp::R_X86_64_16:
|
|
case elfcpp::R_X86_64_8:
|
|
return Symbol::ABSOLUTE_REF;
|
|
|
|
case elfcpp::R_X86_64_PC64:
|
|
case elfcpp::R_X86_64_PC32:
|
|
case elfcpp::R_X86_64_PC16:
|
|
case elfcpp::R_X86_64_PC8:
|
|
case elfcpp::R_X86_64_GOTOFF64:
|
|
return Symbol::RELATIVE_REF;
|
|
|
|
case elfcpp::R_X86_64_PLT32:
|
|
case elfcpp::R_X86_64_PLTOFF64:
|
|
return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF;
|
|
|
|
case elfcpp::R_X86_64_GOT64:
|
|
case elfcpp::R_X86_64_GOT32:
|
|
case elfcpp::R_X86_64_GOTPCREL64:
|
|
case elfcpp::R_X86_64_GOTPCREL:
|
|
case elfcpp::R_X86_64_GOTPLT64:
|
|
// Absolute in GOT.
|
|
return Symbol::ABSOLUTE_REF;
|
|
|
|
case elfcpp::R_X86_64_TLSGD: // Global-dynamic
|
|
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
|
|
case elfcpp::R_X86_64_TLSDESC_CALL:
|
|
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
|
|
case elfcpp::R_X86_64_DTPOFF32:
|
|
case elfcpp::R_X86_64_DTPOFF64:
|
|
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
|
|
case elfcpp::R_X86_64_TPOFF32: // Local-exec
|
|
return Symbol::TLS_REF;
|
|
|
|
case elfcpp::R_X86_64_COPY:
|
|
case elfcpp::R_X86_64_GLOB_DAT:
|
|
case elfcpp::R_X86_64_JUMP_SLOT:
|
|
case elfcpp::R_X86_64_RELATIVE:
|
|
case elfcpp::R_X86_64_IRELATIVE:
|
|
case elfcpp::R_X86_64_TPOFF64:
|
|
case elfcpp::R_X86_64_DTPMOD64:
|
|
case elfcpp::R_X86_64_TLSDESC:
|
|
case elfcpp::R_X86_64_SIZE32:
|
|
case elfcpp::R_X86_64_SIZE64:
|
|
default:
|
|
// Not expected. We will give an error later.
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
// Report an unsupported relocation against a local symbol.
|
|
|
|
void
|
|
Target_x86_64::Scan::unsupported_reloc_local(
|
|
Sized_relobj_file<64, false>* object,
|
|
unsigned int r_type)
|
|
{
|
|
gold_error(_("%s: unsupported reloc %u against local symbol"),
|
|
object->name().c_str(), r_type);
|
|
}
|
|
|
|
// We are about to emit a dynamic relocation of type R_TYPE. If the
|
|
// dynamic linker does not support it, issue an error. The GNU linker
|
|
// only issues a non-PIC error for an allocated read-only section.
|
|
// Here we know the section is allocated, but we don't know that it is
|
|
// read-only. But we check for all the relocation types which the
|
|
// glibc dynamic linker supports, so it seems appropriate to issue an
|
|
// error even if the section is not read-only.
|
|
|
|
void
|
|
Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type)
|
|
{
|
|
switch (r_type)
|
|
{
|
|
// These are the relocation types supported by glibc for x86_64
|
|
// which should always work.
|
|
case elfcpp::R_X86_64_RELATIVE:
|
|
case elfcpp::R_X86_64_IRELATIVE:
|
|
case elfcpp::R_X86_64_GLOB_DAT:
|
|
case elfcpp::R_X86_64_JUMP_SLOT:
|
|
case elfcpp::R_X86_64_DTPMOD64:
|
|
case elfcpp::R_X86_64_DTPOFF64:
|
|
case elfcpp::R_X86_64_TPOFF64:
|
|
case elfcpp::R_X86_64_64:
|
|
case elfcpp::R_X86_64_COPY:
|
|
return;
|
|
|
|
// glibc supports these reloc types, but they can overflow.
|
|
case elfcpp::R_X86_64_32:
|
|
case elfcpp::R_X86_64_PC32:
|
|
if (this->issued_non_pic_error_)
|
|
return;
|
|
gold_assert(parameters->options().output_is_position_independent());
|
|
object->error(_("requires dynamic reloc which may overflow at runtime; "
|
|
"recompile with -fPIC"));
|
|
this->issued_non_pic_error_ = true;
|
|
return;
|
|
|
|
default:
|
|
// This prevents us from issuing more than one error per reloc
|
|
// section. But we can still wind up issuing more than one
|
|
// error per object file.
|
|
if (this->issued_non_pic_error_)
|
|
return;
|
|
gold_assert(parameters->options().output_is_position_independent());
|
|
object->error(_("requires unsupported dynamic reloc; "
|
|
"recompile with -fPIC"));
|
|
this->issued_non_pic_error_ = true;
|
|
return;
|
|
|
|
case elfcpp::R_X86_64_NONE:
|
|
gold_unreachable();
|
|
}
|
|
}
|
|
|
|
// Return whether we need to make a PLT entry for a relocation of the
|
|
// given type against a STT_GNU_IFUNC symbol.
|
|
|
|
bool
|
|
Target_x86_64::Scan::reloc_needs_plt_for_ifunc(
|
|
Sized_relobj_file<64, 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_x86_64::Scan::local(Symbol_table* symtab,
|
|
Layout* layout,
|
|
Target_x86_64* target,
|
|
Sized_relobj_file<64, false>* object,
|
|
unsigned int data_shndx,
|
|
Output_section* output_section,
|
|
const elfcpp::Rela<64, false>& reloc,
|
|
unsigned int r_type,
|
|
const elfcpp::Sym<64, false>& lsym)
|
|
{
|
|
// 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<64>(reloc.get_r_info());
|
|
target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
|
|
}
|
|
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_X86_64_NONE:
|
|
case elfcpp::R_X86_64_GNU_VTINHERIT:
|
|
case elfcpp::R_X86_64_GNU_VTENTRY:
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_64:
|
|
// 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_X86_64_RELATIVE relocation so the dynamic loader can
|
|
// relocate it easily.
|
|
if (parameters->options().output_is_position_independent())
|
|
{
|
|
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
|
|
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
|
|
rela_dyn->add_local_relative(object, r_sym,
|
|
elfcpp::R_X86_64_RELATIVE,
|
|
output_section, data_shndx,
|
|
reloc.get_r_offset(),
|
|
reloc.get_r_addend());
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_32:
|
|
case elfcpp::R_X86_64_32S:
|
|
case elfcpp::R_X86_64_16:
|
|
case elfcpp::R_X86_64_8:
|
|
// If building a shared library (or a position-independent
|
|
// executable), we need to create a dynamic relocation for this
|
|
// location. We can't use an R_X86_64_RELATIVE relocation
|
|
// because that is always a 64-bit relocation.
|
|
if (parameters->options().output_is_position_independent())
|
|
{
|
|
this->check_non_pic(object, r_type);
|
|
|
|
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
|
|
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
|
|
if (lsym.get_st_type() != elfcpp::STT_SECTION)
|
|
rela_dyn->add_local(object, r_sym, r_type, output_section,
|
|
data_shndx, reloc.get_r_offset(),
|
|
reloc.get_r_addend());
|
|
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
|
|
rela_dyn->add_local_section(object, shndx,
|
|
r_type, output_section,
|
|
data_shndx, reloc.get_r_offset(),
|
|
reloc.get_r_addend());
|
|
}
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_PC64:
|
|
case elfcpp::R_X86_64_PC32:
|
|
case elfcpp::R_X86_64_PC16:
|
|
case elfcpp::R_X86_64_PC8:
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_PLT32:
|
|
// Since we know this is a local symbol, we can handle this as a
|
|
// PC32 reloc.
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTPC32:
|
|
case elfcpp::R_X86_64_GOTOFF64:
|
|
case elfcpp::R_X86_64_GOTPC64:
|
|
case elfcpp::R_X86_64_PLTOFF64:
|
|
// We need a GOT section.
|
|
target->got_section(symtab, layout);
|
|
// For PLTOFF64, we'd normally want a PLT section, but since we
|
|
// know this is a local symbol, no PLT is needed.
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOT64:
|
|
case elfcpp::R_X86_64_GOT32:
|
|
case elfcpp::R_X86_64_GOTPCREL64:
|
|
case elfcpp::R_X86_64_GOTPCREL:
|
|
case elfcpp::R_X86_64_GOTPLT64:
|
|
{
|
|
// The symbol requires a GOT entry.
|
|
Output_data_got<64, false>* got = target->got_section(symtab, layout);
|
|
unsigned int r_sym = elfcpp::elf_r_sym<64>(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 relocation for this symbol's GOT entry.
|
|
if (parameters->options().output_is_position_independent())
|
|
{
|
|
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
|
|
// R_X86_64_RELATIVE assumes a 64-bit relocation.
|
|
if (r_type != elfcpp::R_X86_64_GOT32)
|
|
{
|
|
unsigned int got_offset =
|
|
object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
|
|
rela_dyn->add_local_relative(object, r_sym,
|
|
elfcpp::R_X86_64_RELATIVE,
|
|
got, got_offset, 0);
|
|
}
|
|
else
|
|
{
|
|
this->check_non_pic(object, r_type);
|
|
|
|
gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
|
|
rela_dyn->add_local(
|
|
object, r_sym, r_type, got,
|
|
object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0);
|
|
}
|
|
}
|
|
}
|
|
// For GOTPLT64, we'd normally want a PLT section, but since
|
|
// we know this is a local symbol, no PLT is needed.
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_COPY:
|
|
case elfcpp::R_X86_64_GLOB_DAT:
|
|
case elfcpp::R_X86_64_JUMP_SLOT:
|
|
case elfcpp::R_X86_64_RELATIVE:
|
|
case elfcpp::R_X86_64_IRELATIVE:
|
|
// These are outstanding tls relocs, which are unexpected when linking
|
|
case elfcpp::R_X86_64_TPOFF64:
|
|
case elfcpp::R_X86_64_DTPMOD64:
|
|
case elfcpp::R_X86_64_TLSDESC:
|
|
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_X86_64_TLSGD: // Global-dynamic
|
|
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
|
|
case elfcpp::R_X86_64_TLSDESC_CALL:
|
|
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
|
|
case elfcpp::R_X86_64_DTPOFF32:
|
|
case elfcpp::R_X86_64_DTPOFF64:
|
|
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
|
|
case elfcpp::R_X86_64_TPOFF32: // Local-exec
|
|
{
|
|
bool output_is_shared = parameters->options().shared();
|
|
const tls::Tls_optimization optimized_type
|
|
= Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type);
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_X86_64_TLSGD: // General-dynamic
|
|
if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Create a pair of GOT entries for the module index and
|
|
// dtv-relative offset.
|
|
Output_data_got<64, false>* got
|
|
= target->got_section(symtab, layout);
|
|
unsigned int r_sym = elfcpp::elf_r_sym<64>(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_rela(object, r_sym,
|
|
shndx,
|
|
GOT_TYPE_TLS_PAIR,
|
|
target->rela_dyn_section(layout),
|
|
elfcpp::R_X86_64_DTPMOD64, 0);
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_local(object, r_type);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTPC32_TLSDESC:
|
|
target->define_tls_base_symbol(symtab, layout);
|
|
if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Create reserved PLT and GOT entries for the resolver.
|
|
target->reserve_tlsdesc_entries(symtab, layout);
|
|
|
|
// Generate a double GOT entry with an
|
|
// R_X86_64_TLSDESC reloc. The R_X86_64_TLSDESC 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<64, false>* got = target->got_tlsdesc_section();
|
|
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
|
|
if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
|
|
{
|
|
unsigned int got_offset = got->add_constant(0);
|
|
got->add_constant(0);
|
|
object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
|
|
got_offset);
|
|
Reloc_section* rt = target->rela_tlsdesc_section(layout);
|
|
// We store the arguments we need in a vector, and
|
|
// use the index into the vector as the parameter
|
|
// to pass to the target specific routines.
|
|
uintptr_t intarg = target->add_tlsdesc_info(object, r_sym);
|
|
void* arg = reinterpret_cast<void*>(intarg);
|
|
rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg,
|
|
got, got_offset, 0);
|
|
}
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_local(object, r_type);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_TLSDESC_CALL:
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_TLSLD: // 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_X86_64_DTPOFF32:
|
|
case elfcpp::R_X86_64_DTPOFF64:
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
|
|
layout->set_has_static_tls();
|
|
if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Create a GOT entry for the tp-relative offset.
|
|
Output_data_got<64, false>* got
|
|
= target->got_section(symtab, layout);
|
|
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
|
|
got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET,
|
|
target->rela_dyn_section(layout),
|
|
elfcpp::R_X86_64_TPOFF64);
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_local(object, r_type);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_TPOFF32: // Local-exec
|
|
layout->set_has_static_tls();
|
|
if (output_is_shared)
|
|
unsupported_reloc_local(object, r_type);
|
|
break;
|
|
|
|
default:
|
|
gold_unreachable();
|
|
}
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_SIZE32:
|
|
case elfcpp::R_X86_64_SIZE64:
|
|
default:
|
|
gold_error(_("%s: unsupported reloc %u against local symbol"),
|
|
object->name().c_str(), r_type);
|
|
break;
|
|
}
|
|
}
|
|
|
|
|
|
// Report an unsupported relocation against a global symbol.
|
|
|
|
void
|
|
Target_x86_64::Scan::unsupported_reloc_global(
|
|
Sized_relobj_file<64, 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());
|
|
}
|
|
|
|
// Returns true if this relocation type could be that of a function pointer.
|
|
inline bool
|
|
Target_x86_64::Scan::possible_function_pointer_reloc(unsigned int r_type)
|
|
{
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_X86_64_64:
|
|
case elfcpp::R_X86_64_32:
|
|
case elfcpp::R_X86_64_32S:
|
|
case elfcpp::R_X86_64_16:
|
|
case elfcpp::R_X86_64_8:
|
|
case elfcpp::R_X86_64_GOT64:
|
|
case elfcpp::R_X86_64_GOT32:
|
|
case elfcpp::R_X86_64_GOTPCREL64:
|
|
case elfcpp::R_X86_64_GOTPCREL:
|
|
case elfcpp::R_X86_64_GOTPLT64:
|
|
{
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// For safe ICF, scan a relocation for a local symbol to check if it
|
|
// corresponds to a function pointer being taken. In that case mark
|
|
// the function whose pointer was taken as not foldable.
|
|
|
|
inline bool
|
|
Target_x86_64::Scan::local_reloc_may_be_function_pointer(
|
|
Symbol_table* ,
|
|
Layout* ,
|
|
Target_x86_64* ,
|
|
Sized_relobj_file<64, false>* ,
|
|
unsigned int ,
|
|
Output_section* ,
|
|
const elfcpp::Rela<64, false>& ,
|
|
unsigned int r_type,
|
|
const elfcpp::Sym<64, false>&)
|
|
{
|
|
// When building a shared library, do not fold any local symbols as it is
|
|
// not possible to distinguish pointer taken versus a call by looking at
|
|
// the relocation types.
|
|
return (parameters->options().shared()
|
|
|| possible_function_pointer_reloc(r_type));
|
|
}
|
|
|
|
// For safe ICF, scan a relocation for a global symbol to check if it
|
|
// corresponds to a function pointer being taken. In that case mark
|
|
// the function whose pointer was taken as not foldable.
|
|
|
|
inline bool
|
|
Target_x86_64::Scan::global_reloc_may_be_function_pointer(
|
|
Symbol_table*,
|
|
Layout* ,
|
|
Target_x86_64* ,
|
|
Sized_relobj_file<64, false>* ,
|
|
unsigned int ,
|
|
Output_section* ,
|
|
const elfcpp::Rela<64, false>& ,
|
|
unsigned int r_type,
|
|
Symbol* gsym)
|
|
{
|
|
// When building a shared library, do not fold symbols whose visibility
|
|
// is hidden, internal or protected.
|
|
return ((parameters->options().shared()
|
|
&& (gsym->visibility() == elfcpp::STV_INTERNAL
|
|
|| gsym->visibility() == elfcpp::STV_PROTECTED
|
|
|| gsym->visibility() == elfcpp::STV_HIDDEN))
|
|
|| possible_function_pointer_reloc(r_type));
|
|
}
|
|
|
|
// Scan a relocation for a global symbol.
|
|
|
|
inline void
|
|
Target_x86_64::Scan::global(Symbol_table* symtab,
|
|
Layout* layout,
|
|
Target_x86_64* target,
|
|
Sized_relobj_file<64, false>* object,
|
|
unsigned int data_shndx,
|
|
Output_section* output_section,
|
|
const elfcpp::Rela<64, 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_X86_64_NONE:
|
|
case elfcpp::R_X86_64_GNU_VTINHERIT:
|
|
case elfcpp::R_X86_64_GNU_VTENTRY:
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_64:
|
|
case elfcpp::R_X86_64_32:
|
|
case elfcpp::R_X86_64_32S:
|
|
case elfcpp::R_X86_64_16:
|
|
case elfcpp::R_X86_64_8:
|
|
{
|
|
// Make a PLT entry if necessary.
|
|
if (gsym->needs_plt_entry())
|
|
{
|
|
target->make_plt_entry(symtab, layout, gsym);
|
|
// Since this is not a PC-relative relocation, we may be
|
|
// taking the address of a function. In that case we need to
|
|
// set the entry in the dynamic symbol table to the address of
|
|
// the PLT entry.
|
|
if (gsym->is_from_dynobj() && !parameters->options().shared())
|
|
gsym->set_needs_dynsym_value();
|
|
}
|
|
// Make a dynamic relocation if necessary.
|
|
if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
|
|
{
|
|
if (gsym->may_need_copy_reloc())
|
|
{
|
|
target->copy_reloc(symtab, layout, object,
|
|
data_shndx, output_section, gsym, reloc);
|
|
}
|
|
else if (r_type == elfcpp::R_X86_64_64
|
|
&& 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* rela_dyn = target->rela_dyn_section(layout);
|
|
unsigned int r_type = elfcpp::R_X86_64_IRELATIVE;
|
|
rela_dyn->add_symbolless_global_addend(gsym, r_type,
|
|
output_section, object,
|
|
data_shndx,
|
|
reloc.get_r_offset(),
|
|
reloc.get_r_addend());
|
|
}
|
|
else if (r_type == elfcpp::R_X86_64_64
|
|
&& gsym->can_use_relative_reloc(false))
|
|
{
|
|
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
|
|
rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE,
|
|
output_section, object,
|
|
data_shndx,
|
|
reloc.get_r_offset(),
|
|
reloc.get_r_addend());
|
|
}
|
|
else
|
|
{
|
|
this->check_non_pic(object, r_type);
|
|
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
|
|
rela_dyn->add_global(gsym, r_type, output_section, object,
|
|
data_shndx, reloc.get_r_offset(),
|
|
reloc.get_r_addend());
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_PC64:
|
|
case elfcpp::R_X86_64_PC32:
|
|
case elfcpp::R_X86_64_PC16:
|
|
case elfcpp::R_X86_64_PC8:
|
|
{
|
|
// Make a PLT entry if necessary.
|
|
if (gsym->needs_plt_entry())
|
|
target->make_plt_entry(symtab, layout, gsym);
|
|
// Make a dynamic relocation if necessary.
|
|
if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
|
|
{
|
|
if (gsym->may_need_copy_reloc())
|
|
{
|
|
target->copy_reloc(symtab, layout, object,
|
|
data_shndx, output_section, gsym, reloc);
|
|
}
|
|
else
|
|
{
|
|
this->check_non_pic(object, r_type);
|
|
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
|
|
rela_dyn->add_global(gsym, r_type, output_section, object,
|
|
data_shndx, reloc.get_r_offset(),
|
|
reloc.get_r_addend());
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOT64:
|
|
case elfcpp::R_X86_64_GOT32:
|
|
case elfcpp::R_X86_64_GOTPCREL64:
|
|
case elfcpp::R_X86_64_GOTPCREL:
|
|
case elfcpp::R_X86_64_GOTPLT64:
|
|
{
|
|
// The symbol requires a GOT entry.
|
|
Output_data_got<64, false>* got = target->got_section(symtab, layout);
|
|
if (gsym->final_value_is_known())
|
|
{
|
|
// For a STT_GNU_IFUNC symbol we want the PLT address.
|
|
if (gsym->type() == elfcpp::STT_GNU_IFUNC)
|
|
got->add_global_plt(gsym, GOT_TYPE_STANDARD);
|
|
else
|
|
got->add_global(gsym, GOT_TYPE_STANDARD);
|
|
}
|
|
else
|
|
{
|
|
// If this symbol is not fully resolved, we need to add a
|
|
// dynamic relocation for it.
|
|
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
|
|
if (gsym->is_from_dynobj()
|
|
|| gsym->is_undefined()
|
|
|| gsym->is_preemptible()
|
|
|| (gsym->type() == elfcpp::STT_GNU_IFUNC
|
|
&& parameters->options().output_is_position_independent()))
|
|
got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
|
|
elfcpp::R_X86_64_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);
|
|
rela_dyn->add_global_relative(gsym,
|
|
elfcpp::R_X86_64_RELATIVE,
|
|
got, got_off, 0);
|
|
}
|
|
}
|
|
}
|
|
// For GOTPLT64, we also need a PLT entry (but only if the
|
|
// symbol is not fully resolved).
|
|
if (r_type == elfcpp::R_X86_64_GOTPLT64
|
|
&& !gsym->final_value_is_known())
|
|
target->make_plt_entry(symtab, layout, gsym);
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_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_X86_64_GOTPC32:
|
|
case elfcpp::R_X86_64_GOTOFF64:
|
|
case elfcpp::R_X86_64_GOTPC64:
|
|
case elfcpp::R_X86_64_PLTOFF64:
|
|
// We need a GOT section.
|
|
target->got_section(symtab, layout);
|
|
// For PLTOFF64, we also need a PLT entry (but only if the
|
|
// symbol is not fully resolved).
|
|
if (r_type == elfcpp::R_X86_64_PLTOFF64
|
|
&& !gsym->final_value_is_known())
|
|
target->make_plt_entry(symtab, layout, gsym);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_COPY:
|
|
case elfcpp::R_X86_64_GLOB_DAT:
|
|
case elfcpp::R_X86_64_JUMP_SLOT:
|
|
case elfcpp::R_X86_64_RELATIVE:
|
|
case elfcpp::R_X86_64_IRELATIVE:
|
|
// These are outstanding tls relocs, which are unexpected when linking
|
|
case elfcpp::R_X86_64_TPOFF64:
|
|
case elfcpp::R_X86_64_DTPMOD64:
|
|
case elfcpp::R_X86_64_TLSDESC:
|
|
gold_error(_("%s: unexpected reloc %u in object file"),
|
|
object->name().c_str(), r_type);
|
|
break;
|
|
|
|
// These are initial tls relocs, which are expected for global()
|
|
case elfcpp::R_X86_64_TLSGD: // Global-dynamic
|
|
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
|
|
case elfcpp::R_X86_64_TLSDESC_CALL:
|
|
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
|
|
case elfcpp::R_X86_64_DTPOFF32:
|
|
case elfcpp::R_X86_64_DTPOFF64:
|
|
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
|
|
case elfcpp::R_X86_64_TPOFF32: // Local-exec
|
|
{
|
|
const bool is_final = gsym->final_value_is_known();
|
|
const tls::Tls_optimization optimized_type
|
|
= Target_x86_64::optimize_tls_reloc(is_final, r_type);
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_X86_64_TLSGD: // General-dynamic
|
|
if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Create a pair of GOT entries for the module index and
|
|
// dtv-relative offset.
|
|
Output_data_got<64, false>* got
|
|
= target->got_section(symtab, layout);
|
|
got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR,
|
|
target->rela_dyn_section(layout),
|
|
elfcpp::R_X86_64_DTPMOD64,
|
|
elfcpp::R_X86_64_DTPOFF64);
|
|
}
|
|
else if (optimized_type == tls::TLSOPT_TO_IE)
|
|
{
|
|
// Create a GOT entry for the tp-relative offset.
|
|
Output_data_got<64, false>* got
|
|
= target->got_section(symtab, layout);
|
|
got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
|
|
target->rela_dyn_section(layout),
|
|
elfcpp::R_X86_64_TPOFF64);
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_global(object, r_type, gsym);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTPC32_TLSDESC:
|
|
target->define_tls_base_symbol(symtab, layout);
|
|
if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Create reserved PLT and GOT entries for the resolver.
|
|
target->reserve_tlsdesc_entries(symtab, layout);
|
|
|
|
// Create a double GOT entry with an R_X86_64_TLSDESC
|
|
// reloc. The R_X86_64_TLSDESC 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<64, false>* got = target->got_tlsdesc_section();
|
|
Reloc_section* rt = target->rela_tlsdesc_section(layout);
|
|
got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC, rt,
|
|
elfcpp::R_X86_64_TLSDESC, 0);
|
|
}
|
|
else if (optimized_type == tls::TLSOPT_TO_IE)
|
|
{
|
|
// Create a GOT entry for the tp-relative offset.
|
|
Output_data_got<64, false>* got
|
|
= target->got_section(symtab, layout);
|
|
got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
|
|
target->rela_dyn_section(layout),
|
|
elfcpp::R_X86_64_TPOFF64);
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_global(object, r_type, gsym);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_TLSDESC_CALL:
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_TLSLD: // 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_X86_64_DTPOFF32:
|
|
case elfcpp::R_X86_64_DTPOFF64:
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
|
|
layout->set_has_static_tls();
|
|
if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Create a GOT entry for the tp-relative offset.
|
|
Output_data_got<64, false>* got
|
|
= target->got_section(symtab, layout);
|
|
got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET,
|
|
target->rela_dyn_section(layout),
|
|
elfcpp::R_X86_64_TPOFF64);
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_global(object, r_type, gsym);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_TPOFF32: // Local-exec
|
|
layout->set_has_static_tls();
|
|
if (parameters->options().shared())
|
|
unsupported_reloc_local(object, r_type);
|
|
break;
|
|
|
|
default:
|
|
gold_unreachable();
|
|
}
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_SIZE32:
|
|
case elfcpp::R_X86_64_SIZE64:
|
|
default:
|
|
gold_error(_("%s: unsupported reloc %u against global symbol %s"),
|
|
object->name().c_str(), r_type,
|
|
gsym->demangled_name().c_str());
|
|
break;
|
|
}
|
|
}
|
|
|
|
void
|
|
Target_x86_64::gc_process_relocs(Symbol_table* symtab,
|
|
Layout* layout,
|
|
Sized_relobj_file<64, 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_REL)
|
|
{
|
|
return;
|
|
}
|
|
|
|
gold::gc_process_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
|
|
Target_x86_64::Scan,
|
|
Target_x86_64::Relocatable_size_for_reloc>(
|
|
symtab,
|
|
layout,
|
|
this,
|
|
object,
|
|
data_shndx,
|
|
prelocs,
|
|
reloc_count,
|
|
output_section,
|
|
needs_special_offset_handling,
|
|
local_symbol_count,
|
|
plocal_symbols);
|
|
|
|
}
|
|
// Scan relocations for a section.
|
|
|
|
void
|
|
Target_x86_64::scan_relocs(Symbol_table* symtab,
|
|
Layout* layout,
|
|
Sized_relobj_file<64, 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_REL)
|
|
{
|
|
gold_error(_("%s: unsupported REL reloc section"),
|
|
object->name().c_str());
|
|
return;
|
|
}
|
|
|
|
gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
|
|
Target_x86_64::Scan>(
|
|
symtab,
|
|
layout,
|
|
this,
|
|
object,
|
|
data_shndx,
|
|
prelocs,
|
|
reloc_count,
|
|
output_section,
|
|
needs_special_offset_handling,
|
|
local_symbol_count,
|
|
plocal_symbols);
|
|
}
|
|
|
|
// Finalize the sections.
|
|
|
|
void
|
|
Target_x86_64::do_finalize_sections(
|
|
Layout* layout,
|
|
const Input_objects*,
|
|
Symbol_table* symtab)
|
|
{
|
|
const Reloc_section* rel_plt = (this->plt_ == NULL
|
|
? NULL
|
|
: this->plt_->rela_plt());
|
|
layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt,
|
|
this->rela_dyn_, true, false);
|
|
|
|
// Fill in some more dynamic tags.
|
|
Output_data_dynamic* const odyn = layout->dynamic_data();
|
|
if (odyn != NULL)
|
|
{
|
|
if (this->plt_ != NULL
|
|
&& this->plt_->output_section() != NULL
|
|
&& this->plt_->has_tlsdesc_entry())
|
|
{
|
|
unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset();
|
|
unsigned int got_offset = this->plt_->get_tlsdesc_got_offset();
|
|
this->got_->finalize_data_size();
|
|
odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT,
|
|
this->plt_, plt_offset);
|
|
odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT,
|
|
this->got_, got_offset);
|
|
}
|
|
}
|
|
|
|
// 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->rela_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)
|
|
{
|
|
uint64_t data_size = this->got_plt_->current_data_size();
|
|
symtab->get_sized_symbol<64>(sym)->set_symsize(data_size);
|
|
}
|
|
}
|
|
|
|
// Perform a relocation.
|
|
|
|
inline bool
|
|
Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
|
|
Target_x86_64* target,
|
|
Output_section*,
|
|
size_t relnum,
|
|
const elfcpp::Rela<64, false>& rela,
|
|
unsigned int r_type,
|
|
const Sized_symbol<64>* gsym,
|
|
const Symbol_value<64>* psymval,
|
|
unsigned char* view,
|
|
elfcpp::Elf_types<64>::Elf_Addr address,
|
|
section_size_type view_size)
|
|
{
|
|
if (this->skip_call_tls_get_addr_)
|
|
{
|
|
if ((r_type != elfcpp::R_X86_64_PLT32
|
|
&& r_type != elfcpp::R_X86_64_PC32)
|
|
|| gsym == NULL
|
|
|| strcmp(gsym->name(), "__tls_get_addr") != 0)
|
|
{
|
|
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
|
|
_("missing expected TLS relocation"));
|
|
}
|
|
else
|
|
{
|
|
this->skip_call_tls_get_addr_ = false;
|
|
return false;
|
|
}
|
|
}
|
|
|
|
const Sized_relobj_file<64, false>* object = relinfo->object;
|
|
|
|
// Pick the value to use for symbols defined in the PLT.
|
|
Symbol_value<64> symval;
|
|
if (gsym != NULL
|
|
&& gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
|
|
{
|
|
symval.set_output_value(target->plt_section()->address()
|
|
+ gsym->plt_offset());
|
|
psymval = &symval;
|
|
}
|
|
else if (gsym == NULL && psymval->is_ifunc_symbol())
|
|
{
|
|
unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
|
|
if (object->local_has_plt_offset(r_sym))
|
|
{
|
|
symval.set_output_value(target->plt_section()->address()
|
|
+ object->local_plt_offset(r_sym));
|
|
psymval = &symval;
|
|
}
|
|
}
|
|
|
|
const elfcpp::Elf_Xword addend = rela.get_r_addend();
|
|
|
|
// Get the GOT offset if needed.
|
|
// The GOT pointer points to the end of the GOT section.
|
|
// We need to subtract the size of the GOT section to get
|
|
// the actual offset to use in the relocation.
|
|
bool have_got_offset = false;
|
|
unsigned int got_offset = 0;
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_X86_64_GOT32:
|
|
case elfcpp::R_X86_64_GOT64:
|
|
case elfcpp::R_X86_64_GOTPLT64:
|
|
case elfcpp::R_X86_64_GOTPCREL:
|
|
case elfcpp::R_X86_64_GOTPCREL64:
|
|
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<64>(rela.get_r_info());
|
|
gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
|
|
got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
|
|
- target->got_size());
|
|
}
|
|
have_got_offset = true;
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_X86_64_NONE:
|
|
case elfcpp::R_X86_64_GNU_VTINHERIT:
|
|
case elfcpp::R_X86_64_GNU_VTENTRY:
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_64:
|
|
Relocate_functions<64, false>::rela64(view, object, psymval, addend);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_PC64:
|
|
Relocate_functions<64, false>::pcrela64(view, object, psymval, addend,
|
|
address);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_32:
|
|
// FIXME: we need to verify that value + addend fits into 32 bits:
|
|
// uint64_t x = value + addend;
|
|
// x == static_cast<uint64_t>(static_cast<uint32_t>(x))
|
|
// Likewise for other <=32-bit relocations (but see R_X86_64_32S).
|
|
Relocate_functions<64, false>::rela32(view, object, psymval, addend);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_32S:
|
|
// FIXME: we need to verify that value + addend fits into 32 bits:
|
|
// int64_t x = value + addend; // note this quantity is signed!
|
|
// x == static_cast<int64_t>(static_cast<int32_t>(x))
|
|
Relocate_functions<64, false>::rela32(view, object, psymval, addend);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_PC32:
|
|
Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
|
|
address);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_16:
|
|
Relocate_functions<64, false>::rela16(view, object, psymval, addend);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_PC16:
|
|
Relocate_functions<64, false>::pcrela16(view, object, psymval, addend,
|
|
address);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_8:
|
|
Relocate_functions<64, false>::rela8(view, object, psymval, addend);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_PC8:
|
|
Relocate_functions<64, false>::pcrela8(view, object, psymval, addend,
|
|
address);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_PLT32:
|
|
gold_assert(gsym == NULL
|
|
|| gsym->has_plt_offset()
|
|
|| gsym->final_value_is_known()
|
|
|| (gsym->is_defined()
|
|
&& !gsym->is_from_dynobj()
|
|
&& !gsym->is_preemptible()));
|
|
// Note: while this code looks the same as for R_X86_64_PC32, it
|
|
// behaves differently because psymval was set to point to
|
|
// the PLT entry, rather than the symbol, in Scan::global().
|
|
Relocate_functions<64, false>::pcrela32(view, object, psymval, addend,
|
|
address);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_PLTOFF64:
|
|
{
|
|
gold_assert(gsym);
|
|
gold_assert(gsym->has_plt_offset()
|
|
|| gsym->final_value_is_known());
|
|
elfcpp::Elf_types<64>::Elf_Addr got_address;
|
|
got_address = target->got_section(NULL, NULL)->address();
|
|
Relocate_functions<64, false>::rela64(view, object, psymval,
|
|
addend - got_address);
|
|
}
|
|
|
|
case elfcpp::R_X86_64_GOT32:
|
|
gold_assert(have_got_offset);
|
|
Relocate_functions<64, false>::rela32(view, got_offset, addend);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTPC32:
|
|
{
|
|
gold_assert(gsym);
|
|
elfcpp::Elf_types<64>::Elf_Addr value;
|
|
value = target->got_plt_section()->address();
|
|
Relocate_functions<64, false>::pcrela32(view, value, addend, address);
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOT64:
|
|
// The ABI doc says "Like GOT64, but indicates a PLT entry is needed."
|
|
// Since we always add a PLT entry, this is equivalent.
|
|
case elfcpp::R_X86_64_GOTPLT64:
|
|
gold_assert(have_got_offset);
|
|
Relocate_functions<64, false>::rela64(view, got_offset, addend);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTPC64:
|
|
{
|
|
gold_assert(gsym);
|
|
elfcpp::Elf_types<64>::Elf_Addr value;
|
|
value = target->got_plt_section()->address();
|
|
Relocate_functions<64, false>::pcrela64(view, value, addend, address);
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTOFF64:
|
|
{
|
|
elfcpp::Elf_types<64>::Elf_Addr value;
|
|
value = (psymval->value(object, 0)
|
|
- target->got_plt_section()->address());
|
|
Relocate_functions<64, false>::rela64(view, value, addend);
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTPCREL:
|
|
{
|
|
gold_assert(have_got_offset);
|
|
elfcpp::Elf_types<64>::Elf_Addr value;
|
|
value = target->got_plt_section()->address() + got_offset;
|
|
Relocate_functions<64, false>::pcrela32(view, value, addend, address);
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTPCREL64:
|
|
{
|
|
gold_assert(have_got_offset);
|
|
elfcpp::Elf_types<64>::Elf_Addr value;
|
|
value = target->got_plt_section()->address() + got_offset;
|
|
Relocate_functions<64, false>::pcrela64(view, value, addend, address);
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_COPY:
|
|
case elfcpp::R_X86_64_GLOB_DAT:
|
|
case elfcpp::R_X86_64_JUMP_SLOT:
|
|
case elfcpp::R_X86_64_RELATIVE:
|
|
case elfcpp::R_X86_64_IRELATIVE:
|
|
// These are outstanding tls relocs, which are unexpected when linking
|
|
case elfcpp::R_X86_64_TPOFF64:
|
|
case elfcpp::R_X86_64_DTPMOD64:
|
|
case elfcpp::R_X86_64_TLSDESC:
|
|
gold_error_at_location(relinfo, relnum, rela.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_X86_64_TLSGD: // Global-dynamic
|
|
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
|
|
case elfcpp::R_X86_64_TLSDESC_CALL:
|
|
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
|
|
case elfcpp::R_X86_64_DTPOFF32:
|
|
case elfcpp::R_X86_64_DTPOFF64:
|
|
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
|
|
case elfcpp::R_X86_64_TPOFF32: // Local-exec
|
|
this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval,
|
|
view, address, view_size);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_SIZE32:
|
|
case elfcpp::R_X86_64_SIZE64:
|
|
default:
|
|
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
|
|
_("unsupported reloc %u"),
|
|
r_type);
|
|
break;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
// Perform a TLS relocation.
|
|
|
|
inline void
|
|
Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo,
|
|
Target_x86_64* target,
|
|
size_t relnum,
|
|
const elfcpp::Rela<64, false>& rela,
|
|
unsigned int r_type,
|
|
const Sized_symbol<64>* gsym,
|
|
const Symbol_value<64>* psymval,
|
|
unsigned char* view,
|
|
elfcpp::Elf_types<64>::Elf_Addr address,
|
|
section_size_type view_size)
|
|
{
|
|
Output_segment* tls_segment = relinfo->layout->tls_segment();
|
|
|
|
const Sized_relobj_file<64, false>* object = relinfo->object;
|
|
const elfcpp::Elf_Xword addend = rela.get_r_addend();
|
|
elfcpp::Shdr<64, false> data_shdr(relinfo->data_shdr);
|
|
bool is_executable = (data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0;
|
|
|
|
elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0);
|
|
|
|
const bool is_final = (gsym == NULL
|
|
? !parameters->options().shared()
|
|
: gsym->final_value_is_known());
|
|
tls::Tls_optimization optimized_type
|
|
= Target_x86_64::optimize_tls_reloc(is_final, r_type);
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_X86_64_TLSGD: // Global-dynamic
|
|
if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
|
|
{
|
|
// If this code sequence is used in a non-executable section,
|
|
// we will not optimize the R_X86_64_DTPOFF32/64 relocation,
|
|
// on the assumption that it's being used by itself in a debug
|
|
// section. Therefore, in the unlikely event that the code
|
|
// sequence appears in a non-executable section, we simply
|
|
// leave it unoptimized.
|
|
optimized_type = tls::TLSOPT_NONE;
|
|
}
|
|
if (optimized_type == tls::TLSOPT_TO_LE)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
this->tls_gd_to_le(relinfo, relnum, tls_segment,
|
|
rela, r_type, value, view,
|
|
view_size);
|
|
break;
|
|
}
|
|
else
|
|
{
|
|
unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
|
|
? GOT_TYPE_TLS_OFFSET
|
|
: 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<64>(rela.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)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
value = target->got_plt_section()->address() + got_offset;
|
|
this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
|
|
value, view, address, view_size);
|
|
break;
|
|
}
|
|
else if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Relocate the field with the offset of the pair of GOT
|
|
// entries.
|
|
value = target->got_plt_section()->address() + got_offset;
|
|
Relocate_functions<64, false>::pcrela32(view, value, addend,
|
|
address);
|
|
break;
|
|
}
|
|
}
|
|
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
|
|
_("unsupported reloc %u"), r_type);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
|
|
case elfcpp::R_X86_64_TLSDESC_CALL:
|
|
if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
|
|
{
|
|
// See above comment for R_X86_64_TLSGD.
|
|
optimized_type = tls::TLSOPT_NONE;
|
|
}
|
|
if (optimized_type == tls::TLSOPT_TO_LE)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
|
|
rela, r_type, value, view,
|
|
view_size);
|
|
break;
|
|
}
|
|
else
|
|
{
|
|
unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
|
|
? GOT_TYPE_TLS_OFFSET
|
|
: GOT_TYPE_TLS_DESC);
|
|
unsigned int got_offset = 0;
|
|
if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC
|
|
&& 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<64>(rela.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)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
value = target->got_plt_section()->address() + got_offset;
|
|
this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
|
|
rela, r_type, value, view, address,
|
|
view_size);
|
|
break;
|
|
}
|
|
else if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
|
|
{
|
|
// Relocate the field with the offset of the pair of GOT
|
|
// entries.
|
|
value = target->got_plt_section()->address() + got_offset;
|
|
Relocate_functions<64, false>::pcrela32(view, value, addend,
|
|
address);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
|
|
_("unsupported reloc %u"), r_type);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
|
|
if (!is_executable && optimized_type == tls::TLSOPT_TO_LE)
|
|
{
|
|
// See above comment for R_X86_64_TLSGD.
|
|
optimized_type = tls::TLSOPT_NONE;
|
|
}
|
|
if (optimized_type == tls::TLSOPT_TO_LE)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, 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());
|
|
value = target->got_plt_section()->address() + got_offset;
|
|
Relocate_functions<64, false>::pcrela32(view, value, addend,
|
|
address);
|
|
break;
|
|
}
|
|
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
|
|
_("unsupported reloc %u"), r_type);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_DTPOFF32:
|
|
// This relocation type is used in debugging information.
|
|
// In that case we need to not optimize the value. If the
|
|
// section is not executable, then we assume we should not
|
|
// optimize this reloc. See comments above for R_X86_64_TLSGD,
|
|
// R_X86_64_GOTPC32_TLSDESC, R_X86_64_TLSDESC_CALL, and
|
|
// R_X86_64_TLSLD.
|
|
if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
value -= tls_segment->memsz();
|
|
}
|
|
Relocate_functions<64, false>::rela32(view, value, addend);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_DTPOFF64:
|
|
// See R_X86_64_DTPOFF32, just above, for why we check for is_executable.
|
|
if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
value -= tls_segment->memsz();
|
|
}
|
|
Relocate_functions<64, false>::rela64(view, value, addend);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
|
|
if (optimized_type == tls::TLSOPT_TO_LE)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
|
|
rela, r_type, value, view,
|
|
view_size);
|
|
break;
|
|
}
|
|
else if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Relocate the field with the offset of the GOT entry for
|
|
// the tp-relative offset of the symbol.
|
|
unsigned int got_offset;
|
|
if (gsym != NULL)
|
|
{
|
|
gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET));
|
|
got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET)
|
|
- target->got_size());
|
|
}
|
|
else
|
|
{
|
|
unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
|
|
gold_assert(object->local_has_got_offset(r_sym,
|
|
GOT_TYPE_TLS_OFFSET));
|
|
got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET)
|
|
- target->got_size());
|
|
}
|
|
value = target->got_plt_section()->address() + got_offset;
|
|
Relocate_functions<64, false>::pcrela32(view, value, addend, address);
|
|
break;
|
|
}
|
|
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
|
|
_("unsupported reloc type %u"),
|
|
r_type);
|
|
break;
|
|
|
|
case elfcpp::R_X86_64_TPOFF32: // Local-exec
|
|
value -= tls_segment->memsz();
|
|
Relocate_functions<64, false>::rela32(view, value, addend);
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Do a relocation in which we convert a TLS General-Dynamic to an
|
|
// Initial-Exec.
|
|
|
|
inline void
|
|
Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo,
|
|
size_t relnum,
|
|
Output_segment*,
|
|
const elfcpp::Rela<64, false>& rela,
|
|
unsigned int,
|
|
elfcpp::Elf_types<64>::Elf_Addr value,
|
|
unsigned char* view,
|
|
elfcpp::Elf_types<64>::Elf_Addr address,
|
|
section_size_type view_size)
|
|
{
|
|
// .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
|
|
// .word 0x6666; rex64; call __tls_get_addr
|
|
// ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax
|
|
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
|
|
|
|
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
|
|
(memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
|
|
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
|
|
(memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
|
|
|
|
memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16);
|
|
|
|
const elfcpp::Elf_Xword addend = rela.get_r_addend();
|
|
Relocate_functions<64, false>::pcrela32(view + 8, value, addend - 8, address);
|
|
|
|
// 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 a
|
|
// Local-Exec.
|
|
|
|
inline void
|
|
Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo,
|
|
size_t relnum,
|
|
Output_segment* tls_segment,
|
|
const elfcpp::Rela<64, false>& rela,
|
|
unsigned int,
|
|
elfcpp::Elf_types<64>::Elf_Addr value,
|
|
unsigned char* view,
|
|
section_size_type view_size)
|
|
{
|
|
// .byte 0x66; leaq foo@tlsgd(%rip),%rdi;
|
|
// .word 0x6666; rex64; call __tls_get_addr
|
|
// ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax
|
|
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4);
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12);
|
|
|
|
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
|
|
(memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0));
|
|
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
|
|
(memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0));
|
|
|
|
memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16);
|
|
|
|
value -= tls_segment->memsz();
|
|
Relocate_functions<64, false>::rela32(view + 8, value, 0);
|
|
|
|
// 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 TLSDESC-style General-Dynamic to Initial-Exec transition.
|
|
|
|
inline void
|
|
Target_x86_64::Relocate::tls_desc_gd_to_ie(
|
|
const Relocate_info<64, false>* relinfo,
|
|
size_t relnum,
|
|
Output_segment*,
|
|
const elfcpp::Rela<64, false>& rela,
|
|
unsigned int r_type,
|
|
elfcpp::Elf_types<64>::Elf_Addr value,
|
|
unsigned char* view,
|
|
elfcpp::Elf_types<64>::Elf_Addr address,
|
|
section_size_type view_size)
|
|
{
|
|
if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
|
|
{
|
|
// leaq foo@tlsdesc(%rip), %rax
|
|
// ==> movq foo@gottpoff(%rip), %rax
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
|
|
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
|
|
view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
|
|
view[-2] = 0x8b;
|
|
const elfcpp::Elf_Xword addend = rela.get_r_addend();
|
|
Relocate_functions<64, false>::pcrela32(view, value, addend, address);
|
|
}
|
|
else
|
|
{
|
|
// call *foo@tlscall(%rax)
|
|
// ==> nop; nop
|
|
gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
|
|
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
|
|
view[0] == 0xff && view[1] == 0x10);
|
|
view[0] = 0x66;
|
|
view[1] = 0x90;
|
|
}
|
|
}
|
|
|
|
// Do a TLSDESC-style General-Dynamic to Local-Exec transition.
|
|
|
|
inline void
|
|
Target_x86_64::Relocate::tls_desc_gd_to_le(
|
|
const Relocate_info<64, false>* relinfo,
|
|
size_t relnum,
|
|
Output_segment* tls_segment,
|
|
const elfcpp::Rela<64, false>& rela,
|
|
unsigned int r_type,
|
|
elfcpp::Elf_types<64>::Elf_Addr value,
|
|
unsigned char* view,
|
|
section_size_type view_size)
|
|
{
|
|
if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC)
|
|
{
|
|
// leaq foo@tlsdesc(%rip), %rax
|
|
// ==> movq foo@tpoff, %rax
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
|
|
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
|
|
view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05);
|
|
view[-2] = 0xc7;
|
|
view[-1] = 0xc0;
|
|
value -= tls_segment->memsz();
|
|
Relocate_functions<64, false>::rela32(view, value, 0);
|
|
}
|
|
else
|
|
{
|
|
// call *foo@tlscall(%rax)
|
|
// ==> nop; nop
|
|
gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL);
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2);
|
|
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
|
|
view[0] == 0xff && view[1] == 0x10);
|
|
view[0] = 0x66;
|
|
view[1] = 0x90;
|
|
}
|
|
}
|
|
|
|
inline void
|
|
Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo,
|
|
size_t relnum,
|
|
Output_segment*,
|
|
const elfcpp::Rela<64, false>& rela,
|
|
unsigned int,
|
|
elfcpp::Elf_types<64>::Elf_Addr,
|
|
unsigned char* view,
|
|
section_size_type view_size)
|
|
{
|
|
// leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt;
|
|
// ... leq foo@dtpoff(%rax),%reg
|
|
// ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx
|
|
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9);
|
|
|
|
tls::check_tls(relinfo, relnum, rela.get_r_offset(),
|
|
view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d);
|
|
|
|
tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8);
|
|
|
|
memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12);
|
|
|
|
// 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_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo,
|
|
size_t relnum,
|
|
Output_segment* tls_segment,
|
|
const elfcpp::Rela<64, false>& rela,
|
|
unsigned int,
|
|
elfcpp::Elf_types<64>::Elf_Addr value,
|
|
unsigned char* view,
|
|
section_size_type view_size)
|
|
{
|
|
// We need to examine the opcodes to figure out which instruction we
|
|
// are looking at.
|
|
|
|
// movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg
|
|
// addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg
|
|
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3);
|
|
tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4);
|
|
|
|
unsigned char op1 = view[-3];
|
|
unsigned char op2 = view[-2];
|
|
unsigned char op3 = view[-1];
|
|
unsigned char reg = op3 >> 3;
|
|
|
|
if (op2 == 0x8b)
|
|
{
|
|
// movq
|
|
if (op1 == 0x4c)
|
|
view[-3] = 0x49;
|
|
view[-2] = 0xc7;
|
|
view[-1] = 0xc0 | reg;
|
|
}
|
|
else if (reg == 4)
|
|
{
|
|
// Special handling for %rsp.
|
|
if (op1 == 0x4c)
|
|
view[-3] = 0x49;
|
|
view[-2] = 0x81;
|
|
view[-1] = 0xc0 | reg;
|
|
}
|
|
else
|
|
{
|
|
// addq
|
|
if (op1 == 0x4c)
|
|
view[-3] = 0x4d;
|
|
view[-2] = 0x8d;
|
|
view[-1] = 0x80 | reg | (reg << 3);
|
|
}
|
|
|
|
value -= tls_segment->memsz();
|
|
Relocate_functions<64, false>::rela32(view, value, 0);
|
|
}
|
|
|
|
// Relocate section data.
|
|
|
|
void
|
|
Target_x86_64::relocate_section(
|
|
const Relocate_info<64, 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<64>::Elf_Addr address,
|
|
section_size_type view_size,
|
|
const Reloc_symbol_changes* reloc_symbol_changes)
|
|
{
|
|
gold_assert(sh_type == elfcpp::SHT_RELA);
|
|
|
|
gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA,
|
|
Target_x86_64::Relocate>(
|
|
relinfo,
|
|
this,
|
|
prelocs,
|
|
reloc_count,
|
|
output_section,
|
|
needs_special_offset_handling,
|
|
view,
|
|
address,
|
|
view_size,
|
|
reloc_symbol_changes);
|
|
}
|
|
|
|
// Apply an incremental relocation. Incremental relocations always refer
|
|
// to global symbols.
|
|
|
|
void
|
|
Target_x86_64::apply_relocation(
|
|
const Relocate_info<64, false>* relinfo,
|
|
elfcpp::Elf_types<64>::Elf_Addr r_offset,
|
|
unsigned int r_type,
|
|
elfcpp::Elf_types<64>::Elf_Swxword r_addend,
|
|
const Symbol* gsym,
|
|
unsigned char* view,
|
|
elfcpp::Elf_types<64>::Elf_Addr address,
|
|
section_size_type view_size)
|
|
{
|
|
gold::apply_relocation<64, false, Target_x86_64, Target_x86_64::Relocate>(
|
|
relinfo,
|
|
this,
|
|
r_offset,
|
|
r_type,
|
|
r_addend,
|
|
gsym,
|
|
view,
|
|
address,
|
|
view_size);
|
|
}
|
|
|
|
// Return the size of a relocation while scanning during a relocatable
|
|
// link.
|
|
|
|
unsigned int
|
|
Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc(
|
|
unsigned int r_type,
|
|
Relobj* object)
|
|
{
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_X86_64_NONE:
|
|
case elfcpp::R_X86_64_GNU_VTINHERIT:
|
|
case elfcpp::R_X86_64_GNU_VTENTRY:
|
|
case elfcpp::R_X86_64_TLSGD: // Global-dynamic
|
|
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
|
|
case elfcpp::R_X86_64_TLSDESC_CALL:
|
|
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
|
|
case elfcpp::R_X86_64_DTPOFF32:
|
|
case elfcpp::R_X86_64_DTPOFF64:
|
|
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
|
|
case elfcpp::R_X86_64_TPOFF32: // Local-exec
|
|
return 0;
|
|
|
|
case elfcpp::R_X86_64_64:
|
|
case elfcpp::R_X86_64_PC64:
|
|
case elfcpp::R_X86_64_GOTOFF64:
|
|
case elfcpp::R_X86_64_GOTPC64:
|
|
case elfcpp::R_X86_64_PLTOFF64:
|
|
case elfcpp::R_X86_64_GOT64:
|
|
case elfcpp::R_X86_64_GOTPCREL64:
|
|
case elfcpp::R_X86_64_GOTPCREL:
|
|
case elfcpp::R_X86_64_GOTPLT64:
|
|
return 8;
|
|
|
|
case elfcpp::R_X86_64_32:
|
|
case elfcpp::R_X86_64_32S:
|
|
case elfcpp::R_X86_64_PC32:
|
|
case elfcpp::R_X86_64_PLT32:
|
|
case elfcpp::R_X86_64_GOTPC32:
|
|
case elfcpp::R_X86_64_GOT32:
|
|
return 4;
|
|
|
|
case elfcpp::R_X86_64_16:
|
|
case elfcpp::R_X86_64_PC16:
|
|
return 2;
|
|
|
|
case elfcpp::R_X86_64_8:
|
|
case elfcpp::R_X86_64_PC8:
|
|
return 1;
|
|
|
|
case elfcpp::R_X86_64_COPY:
|
|
case elfcpp::R_X86_64_GLOB_DAT:
|
|
case elfcpp::R_X86_64_JUMP_SLOT:
|
|
case elfcpp::R_X86_64_RELATIVE:
|
|
case elfcpp::R_X86_64_IRELATIVE:
|
|
// These are outstanding tls relocs, which are unexpected when linking
|
|
case elfcpp::R_X86_64_TPOFF64:
|
|
case elfcpp::R_X86_64_DTPMOD64:
|
|
case elfcpp::R_X86_64_TLSDESC:
|
|
object->error(_("unexpected reloc %u in object file"), r_type);
|
|
return 0;
|
|
|
|
case elfcpp::R_X86_64_SIZE32:
|
|
case elfcpp::R_X86_64_SIZE64:
|
|
default:
|
|
object->error(_("unsupported reloc %u against local symbol"), r_type);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
// Scan the relocs during a relocatable link.
|
|
|
|
void
|
|
Target_x86_64::scan_relocatable_relocs(Symbol_table* symtab,
|
|
Layout* layout,
|
|
Sized_relobj_file<64, false>* object,
|
|
unsigned int data_shndx,
|
|
unsigned int sh_type,
|
|
const unsigned char* prelocs,
|
|
size_t reloc_count,
|
|
Output_section* output_section,
|
|
bool needs_special_offset_handling,
|
|
size_t local_symbol_count,
|
|
const unsigned char* plocal_symbols,
|
|
Relocatable_relocs* rr)
|
|
{
|
|
gold_assert(sh_type == elfcpp::SHT_RELA);
|
|
|
|
typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_RELA,
|
|
Relocatable_size_for_reloc> Scan_relocatable_relocs;
|
|
|
|
gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA,
|
|
Scan_relocatable_relocs>(
|
|
symtab,
|
|
layout,
|
|
object,
|
|
data_shndx,
|
|
prelocs,
|
|
reloc_count,
|
|
output_section,
|
|
needs_special_offset_handling,
|
|
local_symbol_count,
|
|
plocal_symbols,
|
|
rr);
|
|
}
|
|
|
|
// Relocate a section during a relocatable link.
|
|
|
|
void
|
|
Target_x86_64::relocate_for_relocatable(
|
|
const Relocate_info<64, false>* relinfo,
|
|
unsigned int sh_type,
|
|
const unsigned char* prelocs,
|
|
size_t reloc_count,
|
|
Output_section* output_section,
|
|
off_t offset_in_output_section,
|
|
const Relocatable_relocs* rr,
|
|
unsigned char* view,
|
|
elfcpp::Elf_types<64>::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_RELA);
|
|
|
|
gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>(
|
|
relinfo,
|
|
prelocs,
|
|
reloc_count,
|
|
output_section,
|
|
offset_in_output_section,
|
|
rr,
|
|
view,
|
|
view_address,
|
|
view_size,
|
|
reloc_view,
|
|
reloc_view_size);
|
|
}
|
|
|
|
// Return the value to use for a dynamic which requires special
|
|
// treatment. This is how we support equality comparisons of function
|
|
// pointers across shared library boundaries, as described in the
|
|
// processor specific ABI supplement.
|
|
|
|
uint64_t
|
|
Target_x86_64::do_dynsym_value(const Symbol* gsym) const
|
|
{
|
|
gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
|
|
return this->plt_section()->address() + gsym->plt_offset();
|
|
}
|
|
|
|
// Return a string used to fill a code section with nops to take up
|
|
// the specified length.
|
|
|
|
std::string
|
|
Target_x86_64::do_code_fill(section_size_type length) const
|
|
{
|
|
if (length >= 16)
|
|
{
|
|
// Build a jmpq instruction to skip over the bytes.
|
|
unsigned char jmp[5];
|
|
jmp[0] = 0xe9;
|
|
elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
|
|
return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
|
|
+ std::string(length - 5, '\0'));
|
|
}
|
|
|
|
// Nop sequences of various lengths.
|
|
const char nop1[1] = { 0x90 }; // nop
|
|
const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax
|
|
const char nop3[3] = { 0x0f, 0x1f, 0x00 }; // nop (%rax)
|
|
const char nop4[4] = { 0x0f, 0x1f, 0x40, 0x00}; // nop 0(%rax)
|
|
const char nop5[5] = { 0x0f, 0x1f, 0x44, 0x00, // nop 0(%rax,%rax,1)
|
|
0x00 };
|
|
const char nop6[6] = { 0x66, 0x0f, 0x1f, 0x44, // nopw 0(%rax,%rax,1)
|
|
0x00, 0x00 };
|
|
const char nop7[7] = { 0x0f, 0x1f, 0x80, 0x00, // nopl 0L(%rax)
|
|
0x00, 0x00, 0x00 };
|
|
const char nop8[8] = { 0x0f, 0x1f, 0x84, 0x00, // nopl 0L(%rax,%rax,1)
|
|
0x00, 0x00, 0x00, 0x00 };
|
|
const char nop9[9] = { 0x66, 0x0f, 0x1f, 0x84, // nopw 0L(%rax,%rax,1)
|
|
0x00, 0x00, 0x00, 0x00,
|
|
0x00 };
|
|
const char nop10[10] = { 0x66, 0x2e, 0x0f, 0x1f, // nopw %cs:0L(%rax,%rax,1)
|
|
0x84, 0x00, 0x00, 0x00,
|
|
0x00, 0x00 };
|
|
const char nop11[11] = { 0x66, 0x66, 0x2e, 0x0f, // data16
|
|
0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
|
|
0x00, 0x00, 0x00 };
|
|
const char nop12[12] = { 0x66, 0x66, 0x66, 0x2e, // data16; data16
|
|
0x0f, 0x1f, 0x84, 0x00, // nopw %cs:0L(%rax,%rax,1)
|
|
0x00, 0x00, 0x00, 0x00 };
|
|
const char nop13[13] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
|
|
0x2e, 0x0f, 0x1f, 0x84, // nopw %cs:0L(%rax,%rax,1)
|
|
0x00, 0x00, 0x00, 0x00,
|
|
0x00 };
|
|
const char nop14[14] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
|
|
0x66, 0x2e, 0x0f, 0x1f, // data16
|
|
0x84, 0x00, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
|
|
0x00, 0x00 };
|
|
const char nop15[15] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16
|
|
0x66, 0x66, 0x2e, 0x0f, // data16; data16
|
|
0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1)
|
|
0x00, 0x00, 0x00 };
|
|
|
|
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 addend to use for a target specific relocation. The
|
|
// only target specific relocation is R_X86_64_TLSDESC for a local
|
|
// symbol. We want to set the addend is the offset of the local
|
|
// symbol in the TLS segment.
|
|
|
|
uint64_t
|
|
Target_x86_64::do_reloc_addend(void* arg, unsigned int r_type,
|
|
uint64_t) const
|
|
{
|
|
gold_assert(r_type == elfcpp::R_X86_64_TLSDESC);
|
|
uintptr_t intarg = reinterpret_cast<uintptr_t>(arg);
|
|
gold_assert(intarg < this->tlsdesc_reloc_info_.size());
|
|
const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]);
|
|
const Symbol_value<64>* psymval = ti.object->local_symbol(ti.r_sym);
|
|
gold_assert(psymval->is_tls_symbol());
|
|
// The value of a TLS symbol is the offset in the TLS segment.
|
|
return psymval->value(ti.object, 0);
|
|
}
|
|
|
|
// 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_x86_64::do_calls_non_split(Relobj* object, unsigned int shndx,
|
|
section_offset_type fnoffset,
|
|
section_size_type fnsize,
|
|
unsigned char* view,
|
|
section_size_type view_size,
|
|
std::string* from,
|
|
std::string* to) const
|
|
{
|
|
// The function starts with a comparison of the stack pointer and a
|
|
// field in the TCB. This is followed by a jump.
|
|
|
|
// cmp %fs:NN,%rsp
|
|
if (this->match_view(view, view_size, fnoffset, "\x64\x48\x3b\x24\x25", 5)
|
|
&& fnsize > 9)
|
|
{
|
|
// 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, 8);
|
|
}
|
|
// lea NN(%rsp),%r10
|
|
// lea NN(%rsp),%r11
|
|
else if ((this->match_view(view, view_size, fnoffset,
|
|
"\x4c\x8d\x94\x24", 4)
|
|
|| this->match_view(view, view_size, fnoffset,
|
|
"\x4c\x8d\x9c\x24", 4))
|
|
&& fnsize > 8)
|
|
{
|
|
// 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 + 4;
|
|
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 x86_64 object files.
|
|
|
|
class Target_selector_x86_64 : public Target_selector_freebsd
|
|
{
|
|
public:
|
|
Target_selector_x86_64()
|
|
: Target_selector_freebsd(elfcpp::EM_X86_64, 64, false, "elf64-x86-64",
|
|
"elf64-x86-64-freebsd")
|
|
{ }
|
|
|
|
Target*
|
|
do_instantiate_target()
|
|
{ return new Target_x86_64(); }
|
|
|
|
};
|
|
|
|
Target_selector_x86_64 target_selector_x86_64;
|
|
|
|
} // End anonymous namespace.
|