2259 lines
74 KiB
C++
2259 lines
74 KiB
C++
// i386.cc -- i386 target support for gold.
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// Copyright 2006, 2007 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 "i386.h"
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#include "object.h"
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#include "symtab.h"
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#include "layout.h"
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#include "output.h"
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#include "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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namespace
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{
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using namespace gold;
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class Output_data_plt_i386;
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// The i386 target class.
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// TLS info comes from
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// http://people.redhat.com/drepper/tls.pdf
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// http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
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class Target_i386 : public Sized_target<32, false>
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{
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public:
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typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
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Target_i386()
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: Sized_target<32, false>(&i386_info),
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got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL),
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copy_relocs_(NULL), dynbss_(NULL), got_mod_index_offset_(-1U)
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{ }
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// Scan the relocations to look for symbol adjustments.
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void
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scan_relocs(const General_options& options,
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Symbol_table* symtab,
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Layout* layout,
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Sized_relobj<32, false>* object,
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unsigned int data_shndx,
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unsigned int sh_type,
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const unsigned char* prelocs,
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size_t reloc_count,
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Output_section* output_section,
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bool needs_special_offset_handling,
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size_t local_symbol_count,
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const unsigned char* plocal_symbols);
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// Finalize the sections.
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void
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do_finalize_sections(Layout*);
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// Return the value to use for a dynamic which requires special
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// treatment.
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uint64_t
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do_dynsym_value(const Symbol*) const;
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// Relocate a section.
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void
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relocate_section(const Relocate_info<32, false>*,
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unsigned int sh_type,
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const unsigned char* prelocs,
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size_t reloc_count,
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Output_section* output_section,
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bool needs_special_offset_handling,
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unsigned char* view,
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elfcpp::Elf_types<32>::Elf_Addr view_address,
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section_size_type view_size);
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// 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);
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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(Symbol* sym) const
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{ return strcmp(sym->name(), "___tls_get_addr") == 0; }
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// Return the size of the GOT section.
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section_size_type
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got_size()
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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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private:
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// The class which scans relocations.
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struct Scan
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{
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inline void
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local(const General_options& options, Symbol_table* symtab,
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Layout* layout, Target_i386* target,
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Sized_relobj<32, false>* object,
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unsigned int data_shndx,
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Output_section* output_section,
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const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
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const elfcpp::Sym<32, false>& lsym);
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inline void
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global(const General_options& options, Symbol_table* symtab,
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Layout* layout, Target_i386* target,
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Sized_relobj<32, false>* object,
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unsigned int data_shndx,
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Output_section* output_section,
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const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
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Symbol* gsym);
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static void
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unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
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static void
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unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
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Symbol*);
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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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local_dynamic_type_(LOCAL_DYNAMIC_NONE)
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{ }
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~Relocate()
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{
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if (this->skip_call_tls_get_addr_)
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{
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// FIXME: This needs to specify the location somehow.
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gold_error(_("missing expected TLS relocation"));
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}
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}
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// Return whether the static relocation needs to be applied.
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inline bool
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should_apply_static_reloc(const Sized_symbol<32>* gsym,
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int ref_flags,
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bool is_32bit);
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// Do a relocation. Return false if the caller should not issue
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// any warnings about this relocation.
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inline bool
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relocate(const Relocate_info<32, false>*, Target_i386*, size_t relnum,
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const elfcpp::Rel<32, false>&,
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unsigned int r_type, const Sized_symbol<32>*,
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const Symbol_value<32>*,
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unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
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section_size_type);
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private:
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// Do a TLS relocation.
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inline void
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relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
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size_t relnum, const elfcpp::Rel<32, false>&,
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unsigned int r_type, const Sized_symbol<32>*,
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const Symbol_value<32>*,
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unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
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section_size_type);
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// Do a TLS General-Dynamic to Initial-Exec transition.
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inline void
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tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
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Output_segment* tls_segment,
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const elfcpp::Rel<32, false>&, unsigned int r_type,
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elfcpp::Elf_types<32>::Elf_Addr value,
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unsigned char* view,
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section_size_type view_size);
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// Do a TLS General-Dynamic to Local-Exec transition.
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inline void
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tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
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Output_segment* tls_segment,
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const elfcpp::Rel<32, false>&, unsigned int r_type,
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elfcpp::Elf_types<32>::Elf_Addr value,
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unsigned char* view,
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section_size_type view_size);
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// Do a TLS Local-Dynamic to Local-Exec transition.
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inline void
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tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
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Output_segment* tls_segment,
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const elfcpp::Rel<32, false>&, unsigned int r_type,
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elfcpp::Elf_types<32>::Elf_Addr value,
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unsigned char* view,
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section_size_type view_size);
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// Do a TLS Initial-Exec to Local-Exec transition.
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static inline void
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tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
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Output_segment* tls_segment,
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const elfcpp::Rel<32, false>&, unsigned int r_type,
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elfcpp::Elf_types<32>::Elf_Addr value,
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unsigned char* view,
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section_size_type view_size);
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// We need to keep track of which type of local dynamic relocation
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// we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
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enum Local_dynamic_type
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{
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LOCAL_DYNAMIC_NONE,
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LOCAL_DYNAMIC_SUN,
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LOCAL_DYNAMIC_GNU
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};
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// This is set if we should skip the next reloc, which should be a
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// PLT32 reloc against ___tls_get_addr.
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bool skip_call_tls_get_addr_;
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// The type of local dynamic relocation we have seen in the section
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// being relocated, if any.
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Local_dynamic_type local_dynamic_type_;
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};
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// Adjust TLS relocation type based on the options and whether this
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// is a local symbol.
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static tls::Tls_optimization
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optimize_tls_reloc(bool is_final, int r_type);
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// Get the GOT section, creating it if necessary.
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Output_data_got<32, false>*
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got_section(Symbol_table*, Layout*);
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// Get the GOT PLT section.
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Output_data_space*
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got_plt_section() const
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{
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gold_assert(this->got_plt_ != NULL);
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return this->got_plt_;
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}
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// Create a PLT entry for a global symbol.
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void
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make_plt_entry(Symbol_table*, Layout*, Symbol*);
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// Create a GOT entry for the TLS module index.
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unsigned int
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got_mod_index_entry(Symbol_table* symtab, Layout* layout,
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Sized_relobj<32, false>* object);
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// Get the PLT section.
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const Output_data_plt_i386*
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plt_section() const
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{
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gold_assert(this->plt_ != NULL);
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return this->plt_;
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}
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// Get the dynamic reloc section, creating it if necessary.
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Reloc_section*
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rel_dyn_section(Layout*);
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// Return true if the symbol may need a COPY relocation.
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// References from an executable object to non-function symbols
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// defined in a dynamic object may need a COPY relocation.
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bool
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may_need_copy_reloc(Symbol* gsym)
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{
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return (!parameters->output_is_shared()
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&& gsym->is_from_dynobj()
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&& gsym->type() != elfcpp::STT_FUNC);
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}
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// Copy a relocation against a global symbol.
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void
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copy_reloc(const General_options*, Symbol_table*, Layout*,
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Sized_relobj<32, false>*, unsigned int,
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Output_section*, Symbol*, const elfcpp::Rel<32, false>&);
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// Information about this specific target which we pass to the
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// general Target structure.
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static const Target::Target_info i386_info;
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// The GOT section.
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Output_data_got<32, false>* got_;
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// The PLT section.
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Output_data_plt_i386* plt_;
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// The GOT PLT section.
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Output_data_space* got_plt_;
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// The dynamic reloc section.
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Reloc_section* rel_dyn_;
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// Relocs saved to avoid a COPY reloc.
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Copy_relocs<32, false>* copy_relocs_;
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// Space for variables copied with a COPY reloc.
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Output_data_space* dynbss_;
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// Offset of the GOT entry for the TLS module index;
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unsigned int got_mod_index_offset_;
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};
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const Target::Target_info Target_i386::i386_info =
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{
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32, // size
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false, // is_big_endian
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elfcpp::EM_386, // machine_code
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false, // has_make_symbol
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false, // has_resolve
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true, // has_code_fill
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true, // is_default_stack_executable
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"/usr/lib/libc.so.1", // dynamic_linker
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0x08048000, // default_text_segment_address
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0x1000, // abi_pagesize
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0x1000 // common_pagesize
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};
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// Get the GOT section, creating it if necessary.
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Output_data_got<32, false>*
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Target_i386::got_section(Symbol_table* symtab, Layout* layout)
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{
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if (this->got_ == NULL)
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{
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gold_assert(symtab != NULL && layout != NULL);
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this->got_ = new Output_data_got<32, false>();
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layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
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elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
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this->got_);
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// The old GNU linker creates a .got.plt section. We just
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// create another set of data in the .got section. Note that we
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// always create a PLT if we create a GOT, although the PLT
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// might be empty.
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this->got_plt_ = new Output_data_space(4);
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layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
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elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
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this->got_plt_);
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// The first three entries are reserved.
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this->got_plt_->set_current_data_size(3 * 4);
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// Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
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symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
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this->got_plt_,
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0, 0, elfcpp::STT_OBJECT,
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elfcpp::STB_LOCAL,
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elfcpp::STV_HIDDEN, 0,
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false, false);
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}
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return this->got_;
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}
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// Get the dynamic reloc section, creating it if necessary.
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Target_i386::Reloc_section*
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Target_i386::rel_dyn_section(Layout* layout)
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{
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if (this->rel_dyn_ == NULL)
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{
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gold_assert(layout != NULL);
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this->rel_dyn_ = new Reloc_section();
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layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
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elfcpp::SHF_ALLOC, this->rel_dyn_);
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}
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return this->rel_dyn_;
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}
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// A class to handle the PLT data.
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class Output_data_plt_i386 : public Output_section_data
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{
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public:
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typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
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Output_data_plt_i386(Layout*, Output_data_space*);
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// Add an entry to the PLT.
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void
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add_entry(Symbol* gsym);
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// Return the .rel.plt section data.
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const Reloc_section*
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rel_plt() const
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{ return this->rel_; }
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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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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 for an executable.
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static unsigned char exec_first_plt_entry[plt_entry_size];
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// The first entry in the PLT for a shared object.
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static unsigned char dyn_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 exec_plt_entry[plt_entry_size];
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// Other entries in the PLT for a shared object.
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static unsigned char dyn_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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{ this->set_data_size((this->count_ + 1) * plt_entry_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 .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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};
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// Create the PLT section. The ordinary .got section is an argument,
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// since we need to refer to the start. We also create our own .got
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// section just for PLT entries.
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Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
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Output_data_space* got_plt)
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: Output_section_data(4), got_plt_(got_plt), count_(0)
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{
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this->rel_ = new Reloc_section();
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layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
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elfcpp::SHF_ALLOC, this->rel_);
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}
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void
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Output_data_plt_i386::do_adjust_output_section(Output_section* os)
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{
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// UnixWare sets the entsize of .plt to 4, and so does the old GNU
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// linker, and so do we.
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os->set_entsize(4);
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}
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// Add an entry to the PLT.
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void
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Output_data_plt_i386::add_entry(Symbol* gsym)
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{
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gold_assert(!gsym->has_plt_offset());
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// Note that when setting the PLT offset we skip the initial
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// reserved PLT entry.
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gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
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++this->count_;
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section_offset_type got_offset = this->got_plt_->current_data_size();
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// Every PLT entry needs a GOT entry which points back to the PLT
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// entry (this will be changed by the dynamic linker, normally
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// lazily when the function is called).
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this->got_plt_->set_current_data_size(got_offset + 4);
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// Every PLT entry needs a reloc.
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gsym->set_needs_dynsym_entry();
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this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
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got_offset);
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// Note that we don't need to save the symbol. The contents of the
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// PLT are independent of which symbols are used. The symbols only
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// appear in the relocations.
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}
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// The first entry in the PLT for an executable.
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unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
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{
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0xff, 0x35, // pushl contents of memory address
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0, 0, 0, 0, // replaced with address of .got + 4
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0xff, 0x25, // jmp indirect
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0, 0, 0, 0, // replaced with address of .got + 8
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0, 0, 0, 0 // unused
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};
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// The first entry in the PLT for a shared object.
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unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
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{
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0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
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0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
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0, 0, 0, 0 // unused
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};
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// Subsequent entries in the PLT for an executable.
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|
|
unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
|
|
{
|
|
0xff, 0x25, // jmp indirect
|
|
0, 0, 0, 0, // replaced with address of symbol in .got
|
|
0x68, // pushl immediate
|
|
0, 0, 0, 0, // replaced with offset into relocation table
|
|
0xe9, // jmp relative
|
|
0, 0, 0, 0 // replaced with offset to start of .plt
|
|
};
|
|
|
|
// Subsequent entries in the PLT for a shared object.
|
|
|
|
unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
|
|
{
|
|
0xff, 0xa3, // jmp *offset(%ebx)
|
|
0, 0, 0, 0, // replaced with offset of symbol in .got
|
|
0x68, // pushl immediate
|
|
0, 0, 0, 0, // replaced with offset into relocation table
|
|
0xe9, // jmp relative
|
|
0, 0, 0, 0 // replaced with offset to start of .plt
|
|
};
|
|
|
|
// Write out the PLT. This uses the hand-coded instructions above,
|
|
// and adjusts them as needed. This is all specified by the i386 ELF
|
|
// Processor Supplement.
|
|
|
|
void
|
|
Output_data_plt_i386::do_write(Output_file* of)
|
|
{
|
|
const off_t offset = this->offset();
|
|
const section_size_type oview_size =
|
|
convert_to_section_size_type(this->data_size());
|
|
unsigned char* const oview = of->get_output_view(offset, oview_size);
|
|
|
|
const off_t got_file_offset = this->got_plt_->offset();
|
|
const section_size_type got_size =
|
|
convert_to_section_size_type(this->got_plt_->data_size());
|
|
unsigned char* const got_view = of->get_output_view(got_file_offset,
|
|
got_size);
|
|
|
|
unsigned char* pov = oview;
|
|
|
|
elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
|
|
elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
|
|
|
|
if (parameters->output_is_shared())
|
|
memcpy(pov, dyn_first_plt_entry, plt_entry_size);
|
|
else
|
|
{
|
|
memcpy(pov, exec_first_plt_entry, plt_entry_size);
|
|
elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
|
|
elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
|
|
}
|
|
pov += plt_entry_size;
|
|
|
|
unsigned char* got_pov = got_view;
|
|
|
|
memset(got_pov, 0, 12);
|
|
got_pov += 12;
|
|
|
|
const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
|
|
|
|
unsigned int plt_offset = plt_entry_size;
|
|
unsigned int plt_rel_offset = 0;
|
|
unsigned int got_offset = 12;
|
|
const unsigned int count = this->count_;
|
|
for (unsigned int i = 0;
|
|
i < count;
|
|
++i,
|
|
pov += plt_entry_size,
|
|
got_pov += 4,
|
|
plt_offset += plt_entry_size,
|
|
plt_rel_offset += rel_size,
|
|
got_offset += 4)
|
|
{
|
|
// Set and adjust the PLT entry itself.
|
|
|
|
if (parameters->output_is_shared())
|
|
{
|
|
memcpy(pov, dyn_plt_entry, plt_entry_size);
|
|
elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
|
|
}
|
|
else
|
|
{
|
|
memcpy(pov, exec_plt_entry, plt_entry_size);
|
|
elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
|
|
(got_address
|
|
+ got_offset));
|
|
}
|
|
|
|
elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
|
|
elfcpp::Swap<32, false>::writeval(pov + 12,
|
|
- (plt_offset + plt_entry_size));
|
|
|
|
// Set the entry in the GOT.
|
|
elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
|
|
}
|
|
|
|
gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
|
|
gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
|
|
|
|
of->write_output_view(offset, oview_size, oview);
|
|
of->write_output_view(got_file_offset, got_size, got_view);
|
|
}
|
|
|
|
// Create a PLT entry for a global symbol.
|
|
|
|
void
|
|
Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
|
|
{
|
|
if (gsym->has_plt_offset())
|
|
return;
|
|
|
|
if (this->plt_ == NULL)
|
|
{
|
|
// Create the GOT sections first.
|
|
this->got_section(symtab, layout);
|
|
|
|
this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
|
|
layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
|
|
(elfcpp::SHF_ALLOC
|
|
| elfcpp::SHF_EXECINSTR),
|
|
this->plt_);
|
|
}
|
|
|
|
this->plt_->add_entry(gsym);
|
|
}
|
|
|
|
// Create a GOT entry for the TLS module index.
|
|
|
|
unsigned int
|
|
Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
|
|
Sized_relobj<32, false>* object)
|
|
{
|
|
if (this->got_mod_index_offset_ == -1U)
|
|
{
|
|
gold_assert(symtab != NULL && layout != NULL && object != NULL);
|
|
Reloc_section* rel_dyn = this->rel_dyn_section(layout);
|
|
Output_data_got<32, false>* got = this->got_section(symtab, layout);
|
|
unsigned int got_offset = got->add_constant(0);
|
|
rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got,
|
|
got_offset);
|
|
got->add_constant(0);
|
|
this->got_mod_index_offset_ = got_offset;
|
|
}
|
|
return this->got_mod_index_offset_;
|
|
}
|
|
|
|
// Handle a relocation against a non-function symbol defined in a
|
|
// dynamic object. The traditional way to handle this is to generate
|
|
// a COPY relocation to copy the variable at runtime from the shared
|
|
// object into the executable's data segment. However, this is
|
|
// undesirable in general, as if the size of the object changes in the
|
|
// dynamic object, the executable will no longer work correctly. If
|
|
// this relocation is in a writable section, then we can create a
|
|
// dynamic reloc and the dynamic linker will resolve it to the correct
|
|
// address at runtime. However, we do not want do that if the
|
|
// relocation is in a read-only section, as it would prevent the
|
|
// readonly segment from being shared. And if we have to eventually
|
|
// generate a COPY reloc, then any dynamic relocations will be
|
|
// useless. So this means that if this is a writable section, we need
|
|
// to save the relocation until we see whether we have to create a
|
|
// COPY relocation for this symbol for any other relocation.
|
|
|
|
void
|
|
Target_i386::copy_reloc(const General_options* options,
|
|
Symbol_table* symtab,
|
|
Layout* layout,
|
|
Sized_relobj<32, false>* object,
|
|
unsigned int data_shndx,
|
|
Output_section* output_section,
|
|
Symbol* gsym,
|
|
const elfcpp::Rel<32, false>& rel)
|
|
{
|
|
Sized_symbol<32>* ssym;
|
|
ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(32) (gsym
|
|
SELECT_SIZE(32));
|
|
|
|
if (!Copy_relocs<32, false>::need_copy_reloc(options, object,
|
|
data_shndx, ssym))
|
|
{
|
|
// So far we do not need a COPY reloc. Save this relocation.
|
|
// If it turns out that we never need a COPY reloc for this
|
|
// symbol, then we will emit the relocation.
|
|
if (this->copy_relocs_ == NULL)
|
|
this->copy_relocs_ = new Copy_relocs<32, false>();
|
|
this->copy_relocs_->save(ssym, object, data_shndx, output_section, rel);
|
|
}
|
|
else
|
|
{
|
|
// Allocate space for this symbol in the .bss section.
|
|
|
|
elfcpp::Elf_types<32>::Elf_WXword symsize = ssym->symsize();
|
|
|
|
// There is no defined way to determine the required alignment
|
|
// of the symbol. We pick the alignment based on the size. We
|
|
// set an arbitrary maximum of 256.
|
|
unsigned int align;
|
|
for (align = 1; align < 512; align <<= 1)
|
|
if ((symsize & align) != 0)
|
|
break;
|
|
|
|
if (this->dynbss_ == NULL)
|
|
{
|
|
this->dynbss_ = new Output_data_space(align);
|
|
layout->add_output_section_data(".bss",
|
|
elfcpp::SHT_NOBITS,
|
|
(elfcpp::SHF_ALLOC
|
|
| elfcpp::SHF_WRITE),
|
|
this->dynbss_);
|
|
}
|
|
|
|
Output_data_space* dynbss = this->dynbss_;
|
|
|
|
if (align > dynbss->addralign())
|
|
dynbss->set_space_alignment(align);
|
|
|
|
section_size_type dynbss_size =
|
|
convert_to_section_size_type(dynbss->current_data_size());
|
|
dynbss_size = align_address(dynbss_size, align);
|
|
section_size_type offset = dynbss_size;
|
|
dynbss->set_current_data_size(dynbss_size + symsize);
|
|
|
|
symtab->define_with_copy_reloc(ssym, dynbss, offset);
|
|
|
|
// Add the COPY reloc.
|
|
Reloc_section* rel_dyn = this->rel_dyn_section(layout);
|
|
rel_dyn->add_global(ssym, elfcpp::R_386_COPY, dynbss, offset);
|
|
}
|
|
}
|
|
|
|
// Optimize the TLS relocation type based on what we know about the
|
|
// symbol. IS_FINAL is true if the final address of this symbol is
|
|
// known at link time.
|
|
|
|
tls::Tls_optimization
|
|
Target_i386::optimize_tls_reloc(bool is_final, int r_type)
|
|
{
|
|
// If we are generating a shared library, then we can't do anything
|
|
// in the linker.
|
|
if (parameters->output_is_shared())
|
|
return tls::TLSOPT_NONE;
|
|
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_386_TLS_GD:
|
|
case elfcpp::R_386_TLS_GOTDESC:
|
|
case elfcpp::R_386_TLS_DESC_CALL:
|
|
// These are General-Dynamic which permits fully general TLS
|
|
// access. Since we know that we are generating an executable,
|
|
// we can convert this to Initial-Exec. If we also know that
|
|
// this is a local symbol, we can further switch to Local-Exec.
|
|
if (is_final)
|
|
return tls::TLSOPT_TO_LE;
|
|
return tls::TLSOPT_TO_IE;
|
|
|
|
case elfcpp::R_386_TLS_LDM:
|
|
// This is Local-Dynamic, which refers to a local symbol in the
|
|
// dynamic TLS block. Since we know that we generating an
|
|
// executable, we can switch to Local-Exec.
|
|
return tls::TLSOPT_TO_LE;
|
|
|
|
case elfcpp::R_386_TLS_LDO_32:
|
|
// Another type of Local-Dynamic relocation.
|
|
return tls::TLSOPT_TO_LE;
|
|
|
|
case elfcpp::R_386_TLS_IE:
|
|
case elfcpp::R_386_TLS_GOTIE:
|
|
case elfcpp::R_386_TLS_IE_32:
|
|
// These are Initial-Exec relocs which get the thread offset
|
|
// from the GOT. If we know that we are linking against the
|
|
// local symbol, we can switch to Local-Exec, which links the
|
|
// thread offset into the instruction.
|
|
if (is_final)
|
|
return tls::TLSOPT_TO_LE;
|
|
return tls::TLSOPT_NONE;
|
|
|
|
case elfcpp::R_386_TLS_LE:
|
|
case elfcpp::R_386_TLS_LE_32:
|
|
// When we already have Local-Exec, there is nothing further we
|
|
// can do.
|
|
return tls::TLSOPT_NONE;
|
|
|
|
default:
|
|
gold_unreachable();
|
|
}
|
|
}
|
|
|
|
// Report an unsupported relocation against a local symbol.
|
|
|
|
void
|
|
Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
|
|
unsigned int r_type)
|
|
{
|
|
gold_error(_("%s: unsupported reloc %u against local symbol"),
|
|
object->name().c_str(), r_type);
|
|
}
|
|
|
|
// Scan a relocation for a local symbol.
|
|
|
|
inline void
|
|
Target_i386::Scan::local(const General_options&,
|
|
Symbol_table* symtab,
|
|
Layout* layout,
|
|
Target_i386* target,
|
|
Sized_relobj<32, false>* object,
|
|
unsigned int data_shndx,
|
|
Output_section* output_section,
|
|
const elfcpp::Rel<32, false>& reloc,
|
|
unsigned int r_type,
|
|
const elfcpp::Sym<32, false>& lsym)
|
|
{
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_386_NONE:
|
|
case elfcpp::R_386_GNU_VTINHERIT:
|
|
case elfcpp::R_386_GNU_VTENTRY:
|
|
break;
|
|
|
|
case elfcpp::R_386_32:
|
|
// If building a shared library (or a position-independent
|
|
// executable), we need to create a dynamic relocation for
|
|
// this location. The relocation applied at link time will
|
|
// apply the link-time value, so we flag the location with
|
|
// an R_386_RELATIVE relocation so the dynamic loader can
|
|
// relocate it easily.
|
|
if (parameters->output_is_position_independent())
|
|
{
|
|
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
|
|
unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
|
|
rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
|
|
output_section, data_shndx,
|
|
reloc.get_r_offset());
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_16:
|
|
case elfcpp::R_386_8:
|
|
// If building a shared library (or a position-independent
|
|
// executable), we need to create a dynamic relocation for
|
|
// this location. Because the addend needs to remain in the
|
|
// data section, we need to be careful not to apply this
|
|
// relocation statically.
|
|
if (parameters->output_is_position_independent())
|
|
{
|
|
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
|
|
unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
|
|
rel_dyn->add_local(object, r_sym, r_type, output_section, data_shndx,
|
|
reloc.get_r_offset());
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_PC32:
|
|
case elfcpp::R_386_PC16:
|
|
case elfcpp::R_386_PC8:
|
|
break;
|
|
|
|
case elfcpp::R_386_PLT32:
|
|
// Since we know this is a local symbol, we can handle this as a
|
|
// PC32 reloc.
|
|
break;
|
|
|
|
case elfcpp::R_386_GOTOFF:
|
|
case elfcpp::R_386_GOTPC:
|
|
// We need a GOT section.
|
|
target->got_section(symtab, layout);
|
|
break;
|
|
|
|
case elfcpp::R_386_GOT32:
|
|
{
|
|
// The symbol requires a GOT entry.
|
|
Output_data_got<32, false>* got = target->got_section(symtab, layout);
|
|
unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
|
|
if (got->add_local(object, r_sym))
|
|
{
|
|
// If we are generating a shared object, we need to add a
|
|
// dynamic RELATIVE relocation for this symbol's GOT entry.
|
|
if (parameters->output_is_position_independent())
|
|
{
|
|
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
|
|
unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
|
|
rel_dyn->add_local_relative(object, r_sym,
|
|
elfcpp::R_386_RELATIVE,
|
|
got,
|
|
object->local_got_offset(r_sym));
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
|
|
// These are relocations which should only be seen by the
|
|
// dynamic linker, and should never be seen here.
|
|
case elfcpp::R_386_COPY:
|
|
case elfcpp::R_386_GLOB_DAT:
|
|
case elfcpp::R_386_JUMP_SLOT:
|
|
case elfcpp::R_386_RELATIVE:
|
|
case elfcpp::R_386_TLS_TPOFF:
|
|
case elfcpp::R_386_TLS_DTPMOD32:
|
|
case elfcpp::R_386_TLS_DTPOFF32:
|
|
case elfcpp::R_386_TLS_TPOFF32:
|
|
case elfcpp::R_386_TLS_DESC:
|
|
gold_error(_("%s: unexpected reloc %u in object file"),
|
|
object->name().c_str(), r_type);
|
|
break;
|
|
|
|
// These are initial TLS relocs, which are expected when
|
|
// linking.
|
|
case elfcpp::R_386_TLS_GD: // Global-dynamic
|
|
case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
|
|
case elfcpp::R_386_TLS_DESC_CALL:
|
|
case elfcpp::R_386_TLS_LDM: // Local-dynamic
|
|
case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
|
|
case elfcpp::R_386_TLS_IE: // Initial-exec
|
|
case elfcpp::R_386_TLS_IE_32:
|
|
case elfcpp::R_386_TLS_GOTIE:
|
|
case elfcpp::R_386_TLS_LE: // Local-exec
|
|
case elfcpp::R_386_TLS_LE_32:
|
|
{
|
|
bool output_is_shared = parameters->output_is_shared();
|
|
const tls::Tls_optimization optimized_type
|
|
= Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_386_TLS_GD: // Global-dynamic
|
|
if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Create a pair of GOT entries for the module index and
|
|
// dtv-relative offset.
|
|
Output_data_got<32, false>* got
|
|
= target->got_section(symtab, layout);
|
|
unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
|
|
got->add_local_tls_with_rel(object, r_sym,
|
|
lsym.get_st_shndx(), true,
|
|
target->rel_dyn_section(layout),
|
|
elfcpp::R_386_TLS_DTPMOD32);
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_local(object, r_type);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva)
|
|
case elfcpp::R_386_TLS_DESC_CALL:
|
|
// FIXME: If not relaxing to LE, we need to generate
|
|
// a GOT entry with an R_386_TLS_DESC reloc.
|
|
if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_local(object, r_type);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_LDM: // Local-dynamic
|
|
if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Create a GOT entry for the module index.
|
|
target->got_mod_index_entry(symtab, layout, object);
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_local(object, r_type);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_IE: // Initial-exec
|
|
case elfcpp::R_386_TLS_IE_32:
|
|
case elfcpp::R_386_TLS_GOTIE:
|
|
layout->set_has_static_tls();
|
|
if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// For the R_386_TLS_IE relocation, we need to create a
|
|
// dynamic relocation when building a shared library.
|
|
if (r_type == elfcpp::R_386_TLS_IE
|
|
&& parameters->output_is_shared())
|
|
{
|
|
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
|
|
unsigned int r_sym
|
|
= elfcpp::elf_r_sym<32>(reloc.get_r_info());
|
|
rel_dyn->add_local_relative(object, r_sym,
|
|
elfcpp::R_386_RELATIVE,
|
|
output_section, data_shndx,
|
|
reloc.get_r_offset());
|
|
}
|
|
// Create a GOT entry for the tp-relative offset.
|
|
Output_data_got<32, false>* got
|
|
= target->got_section(symtab, layout);
|
|
unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
|
|
unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
|
|
? elfcpp::R_386_TLS_TPOFF32
|
|
: elfcpp::R_386_TLS_TPOFF);
|
|
got->add_local_with_rel(object, r_sym,
|
|
target->rel_dyn_section(layout),
|
|
dyn_r_type);
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_local(object, r_type);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_LE: // Local-exec
|
|
case elfcpp::R_386_TLS_LE_32:
|
|
layout->set_has_static_tls();
|
|
if (output_is_shared)
|
|
{
|
|
// We need to create a dynamic relocation.
|
|
unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
|
|
unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
|
|
? elfcpp::R_386_TLS_TPOFF32
|
|
: elfcpp::R_386_TLS_TPOFF);
|
|
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
|
|
rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
|
|
data_shndx, reloc.get_r_offset());
|
|
}
|
|
break;
|
|
|
|
default:
|
|
gold_unreachable();
|
|
}
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_32PLT:
|
|
case elfcpp::R_386_TLS_GD_32:
|
|
case elfcpp::R_386_TLS_GD_PUSH:
|
|
case elfcpp::R_386_TLS_GD_CALL:
|
|
case elfcpp::R_386_TLS_GD_POP:
|
|
case elfcpp::R_386_TLS_LDM_32:
|
|
case elfcpp::R_386_TLS_LDM_PUSH:
|
|
case elfcpp::R_386_TLS_LDM_CALL:
|
|
case elfcpp::R_386_TLS_LDM_POP:
|
|
case elfcpp::R_386_USED_BY_INTEL_200:
|
|
default:
|
|
unsupported_reloc_local(object, r_type);
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Report an unsupported relocation against a global symbol.
|
|
|
|
void
|
|
Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
|
|
unsigned int r_type,
|
|
Symbol* gsym)
|
|
{
|
|
gold_error(_("%s: unsupported reloc %u against global symbol %s"),
|
|
object->name().c_str(), r_type, gsym->demangled_name().c_str());
|
|
}
|
|
|
|
// Scan a relocation for a global symbol.
|
|
|
|
inline void
|
|
Target_i386::Scan::global(const General_options& options,
|
|
Symbol_table* symtab,
|
|
Layout* layout,
|
|
Target_i386* target,
|
|
Sized_relobj<32, false>* object,
|
|
unsigned int data_shndx,
|
|
Output_section* output_section,
|
|
const elfcpp::Rel<32, false>& reloc,
|
|
unsigned int r_type,
|
|
Symbol* gsym)
|
|
{
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_386_NONE:
|
|
case elfcpp::R_386_GNU_VTINHERIT:
|
|
case elfcpp::R_386_GNU_VTENTRY:
|
|
break;
|
|
|
|
case elfcpp::R_386_32:
|
|
case elfcpp::R_386_16:
|
|
case elfcpp::R_386_8:
|
|
{
|
|
// Make a PLT entry if necessary.
|
|
if (gsym->needs_plt_entry())
|
|
{
|
|
target->make_plt_entry(symtab, layout, gsym);
|
|
// Since this is not a PC-relative relocation, we may be
|
|
// taking the address of a function. In that case we need to
|
|
// set the entry in the dynamic symbol table to the address of
|
|
// the PLT entry.
|
|
if (gsym->is_from_dynobj())
|
|
gsym->set_needs_dynsym_value();
|
|
}
|
|
// Make a dynamic relocation if necessary.
|
|
if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
|
|
{
|
|
if (target->may_need_copy_reloc(gsym))
|
|
{
|
|
target->copy_reloc(&options, symtab, layout, object,
|
|
data_shndx, output_section, gsym, reloc);
|
|
}
|
|
else if (r_type == elfcpp::R_386_32
|
|
&& gsym->can_use_relative_reloc(false))
|
|
{
|
|
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
|
|
rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
|
|
output_section, object,
|
|
data_shndx, reloc.get_r_offset());
|
|
}
|
|
else
|
|
{
|
|
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
|
|
rel_dyn->add_global(gsym, r_type, output_section, object,
|
|
data_shndx, reloc.get_r_offset());
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_PC32:
|
|
case elfcpp::R_386_PC16:
|
|
case elfcpp::R_386_PC8:
|
|
{
|
|
// Make a PLT entry if necessary.
|
|
if (gsym->needs_plt_entry())
|
|
{
|
|
// These relocations are used for function calls only in
|
|
// non-PIC code. For a 32-bit relocation in a shared library,
|
|
// we'll need a text relocation anyway, so we can skip the
|
|
// PLT entry and let the dynamic linker bind the call directly
|
|
// to the target. For smaller relocations, we should use a
|
|
// PLT entry to ensure that the call can reach.
|
|
if (!parameters->output_is_shared()
|
|
|| r_type != elfcpp::R_386_PC32)
|
|
target->make_plt_entry(symtab, layout, gsym);
|
|
}
|
|
// Make a dynamic relocation if necessary.
|
|
int flags = Symbol::NON_PIC_REF;
|
|
if (gsym->type() == elfcpp::STT_FUNC)
|
|
flags |= Symbol::FUNCTION_CALL;
|
|
if (gsym->needs_dynamic_reloc(flags))
|
|
{
|
|
if (target->may_need_copy_reloc(gsym))
|
|
{
|
|
target->copy_reloc(&options, symtab, layout, object,
|
|
data_shndx, output_section, gsym, reloc);
|
|
}
|
|
else
|
|
{
|
|
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
|
|
rel_dyn->add_global(gsym, r_type, output_section, object,
|
|
data_shndx, reloc.get_r_offset());
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_GOT32:
|
|
{
|
|
// The symbol requires a GOT entry.
|
|
Output_data_got<32, false>* got = target->got_section(symtab, layout);
|
|
if (gsym->final_value_is_known())
|
|
got->add_global(gsym);
|
|
else
|
|
{
|
|
// If this symbol is not fully resolved, we need to add a
|
|
// GOT entry with a dynamic relocation.
|
|
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
|
|
if (gsym->is_from_dynobj() || gsym->is_preemptible())
|
|
got->add_global_with_rel(gsym, rel_dyn, elfcpp::R_386_GLOB_DAT);
|
|
else
|
|
{
|
|
if (got->add_global(gsym))
|
|
rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
|
|
got, gsym->got_offset());
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_PLT32:
|
|
// If the symbol is fully resolved, this is just a PC32 reloc.
|
|
// Otherwise we need a PLT entry.
|
|
if (gsym->final_value_is_known())
|
|
break;
|
|
// If building a shared library, we can also skip the PLT entry
|
|
// if the symbol is defined in the output file and is protected
|
|
// or hidden.
|
|
if (gsym->is_defined()
|
|
&& !gsym->is_from_dynobj()
|
|
&& !gsym->is_preemptible())
|
|
break;
|
|
target->make_plt_entry(symtab, layout, gsym);
|
|
break;
|
|
|
|
case elfcpp::R_386_GOTOFF:
|
|
case elfcpp::R_386_GOTPC:
|
|
// We need a GOT section.
|
|
target->got_section(symtab, layout);
|
|
break;
|
|
|
|
// These are relocations which should only be seen by the
|
|
// dynamic linker, and should never be seen here.
|
|
case elfcpp::R_386_COPY:
|
|
case elfcpp::R_386_GLOB_DAT:
|
|
case elfcpp::R_386_JUMP_SLOT:
|
|
case elfcpp::R_386_RELATIVE:
|
|
case elfcpp::R_386_TLS_TPOFF:
|
|
case elfcpp::R_386_TLS_DTPMOD32:
|
|
case elfcpp::R_386_TLS_DTPOFF32:
|
|
case elfcpp::R_386_TLS_TPOFF32:
|
|
case elfcpp::R_386_TLS_DESC:
|
|
gold_error(_("%s: unexpected reloc %u in object file"),
|
|
object->name().c_str(), r_type);
|
|
break;
|
|
|
|
// These are initial tls relocs, which are expected when
|
|
// linking.
|
|
case elfcpp::R_386_TLS_GD: // Global-dynamic
|
|
case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
|
|
case elfcpp::R_386_TLS_DESC_CALL:
|
|
case elfcpp::R_386_TLS_LDM: // Local-dynamic
|
|
case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
|
|
case elfcpp::R_386_TLS_IE: // Initial-exec
|
|
case elfcpp::R_386_TLS_IE_32:
|
|
case elfcpp::R_386_TLS_GOTIE:
|
|
case elfcpp::R_386_TLS_LE: // Local-exec
|
|
case elfcpp::R_386_TLS_LE_32:
|
|
{
|
|
const bool is_final = gsym->final_value_is_known();
|
|
const tls::Tls_optimization optimized_type
|
|
= Target_i386::optimize_tls_reloc(is_final, r_type);
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_386_TLS_GD: // Global-dynamic
|
|
if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Create a pair of GOT entries for the module index and
|
|
// dtv-relative offset.
|
|
Output_data_got<32, false>* got
|
|
= target->got_section(symtab, layout);
|
|
got->add_global_tls_with_rel(gsym,
|
|
target->rel_dyn_section(layout),
|
|
elfcpp::R_386_TLS_DTPMOD32,
|
|
elfcpp::R_386_TLS_DTPOFF32);
|
|
}
|
|
else if (optimized_type == tls::TLSOPT_TO_IE)
|
|
{
|
|
// Create a GOT entry for the tp-relative offset.
|
|
Output_data_got<32, false>* got
|
|
= target->got_section(symtab, layout);
|
|
got->add_global_with_rel(gsym, target->rel_dyn_section(layout),
|
|
elfcpp::R_386_TLS_TPOFF32);
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_global(object, r_type, gsym);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url)
|
|
case elfcpp::R_386_TLS_DESC_CALL:
|
|
// FIXME: If not relaxing to LE, we need to generate
|
|
// a GOT entry with an R_386_TLS_DESC reloc.
|
|
if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_global(object, r_type, gsym);
|
|
unsupported_reloc_global(object, r_type, gsym);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_LDM: // Local-dynamic
|
|
if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Create a GOT entry for the module index.
|
|
target->got_mod_index_entry(symtab, layout, object);
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_global(object, r_type, gsym);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_IE: // Initial-exec
|
|
case elfcpp::R_386_TLS_IE_32:
|
|
case elfcpp::R_386_TLS_GOTIE:
|
|
layout->set_has_static_tls();
|
|
if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// For the R_386_TLS_IE relocation, we need to create a
|
|
// dynamic relocation when building a shared library.
|
|
if (r_type == elfcpp::R_386_TLS_IE
|
|
&& parameters->output_is_shared())
|
|
{
|
|
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
|
|
rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
|
|
output_section, object,
|
|
data_shndx,
|
|
reloc.get_r_offset());
|
|
}
|
|
// Create a GOT entry for the tp-relative offset.
|
|
Output_data_got<32, false>* got
|
|
= target->got_section(symtab, layout);
|
|
unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
|
|
? elfcpp::R_386_TLS_TPOFF32
|
|
: elfcpp::R_386_TLS_TPOFF);
|
|
got->add_global_with_rel(gsym,
|
|
target->rel_dyn_section(layout),
|
|
dyn_r_type);
|
|
}
|
|
else if (optimized_type != tls::TLSOPT_TO_LE)
|
|
unsupported_reloc_global(object, r_type, gsym);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_LE: // Local-exec
|
|
case elfcpp::R_386_TLS_LE_32:
|
|
layout->set_has_static_tls();
|
|
if (parameters->output_is_shared())
|
|
{
|
|
// We need to create a dynamic relocation.
|
|
unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
|
|
? elfcpp::R_386_TLS_TPOFF32
|
|
: elfcpp::R_386_TLS_TPOFF);
|
|
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
|
|
rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
|
|
data_shndx, reloc.get_r_offset());
|
|
}
|
|
break;
|
|
|
|
default:
|
|
gold_unreachable();
|
|
}
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_32PLT:
|
|
case elfcpp::R_386_TLS_GD_32:
|
|
case elfcpp::R_386_TLS_GD_PUSH:
|
|
case elfcpp::R_386_TLS_GD_CALL:
|
|
case elfcpp::R_386_TLS_GD_POP:
|
|
case elfcpp::R_386_TLS_LDM_32:
|
|
case elfcpp::R_386_TLS_LDM_PUSH:
|
|
case elfcpp::R_386_TLS_LDM_CALL:
|
|
case elfcpp::R_386_TLS_LDM_POP:
|
|
case elfcpp::R_386_USED_BY_INTEL_200:
|
|
default:
|
|
unsupported_reloc_global(object, r_type, gsym);
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Scan relocations for a section.
|
|
|
|
void
|
|
Target_i386::scan_relocs(const General_options& options,
|
|
Symbol_table* symtab,
|
|
Layout* layout,
|
|
Sized_relobj<32, false>* object,
|
|
unsigned int data_shndx,
|
|
unsigned int sh_type,
|
|
const unsigned char* prelocs,
|
|
size_t reloc_count,
|
|
Output_section* output_section,
|
|
bool needs_special_offset_handling,
|
|
size_t local_symbol_count,
|
|
const unsigned char* plocal_symbols)
|
|
{
|
|
if (sh_type == elfcpp::SHT_RELA)
|
|
{
|
|
gold_error(_("%s: unsupported RELA reloc section"),
|
|
object->name().c_str());
|
|
return;
|
|
}
|
|
|
|
gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
|
|
Target_i386::Scan>(
|
|
options,
|
|
symtab,
|
|
layout,
|
|
this,
|
|
object,
|
|
data_shndx,
|
|
prelocs,
|
|
reloc_count,
|
|
output_section,
|
|
needs_special_offset_handling,
|
|
local_symbol_count,
|
|
plocal_symbols);
|
|
}
|
|
|
|
// Finalize the sections.
|
|
|
|
void
|
|
Target_i386::do_finalize_sections(Layout* layout)
|
|
{
|
|
// Fill in some more dynamic tags.
|
|
Output_data_dynamic* const odyn = layout->dynamic_data();
|
|
if (odyn != NULL)
|
|
{
|
|
if (this->got_plt_ != NULL)
|
|
odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
|
|
|
|
if (this->plt_ != NULL)
|
|
{
|
|
const Output_data* od = this->plt_->rel_plt();
|
|
odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
|
|
odyn->add_section_address(elfcpp::DT_JMPREL, od);
|
|
odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
|
|
}
|
|
|
|
if (this->rel_dyn_ != NULL)
|
|
{
|
|
const Output_data* od = this->rel_dyn_;
|
|
odyn->add_section_address(elfcpp::DT_REL, od);
|
|
odyn->add_section_size(elfcpp::DT_RELSZ, od);
|
|
odyn->add_constant(elfcpp::DT_RELENT,
|
|
elfcpp::Elf_sizes<32>::rel_size);
|
|
}
|
|
|
|
if (!parameters->output_is_shared())
|
|
{
|
|
// The value of the DT_DEBUG tag is filled in by the dynamic
|
|
// linker at run time, and used by the debugger.
|
|
odyn->add_constant(elfcpp::DT_DEBUG, 0);
|
|
}
|
|
}
|
|
|
|
// Emit any relocs we saved in an attempt to avoid generating COPY
|
|
// relocs.
|
|
if (this->copy_relocs_ == NULL)
|
|
return;
|
|
if (this->copy_relocs_->any_to_emit())
|
|
{
|
|
Reloc_section* rel_dyn = this->rel_dyn_section(layout);
|
|
this->copy_relocs_->emit(rel_dyn);
|
|
}
|
|
delete this->copy_relocs_;
|
|
this->copy_relocs_ = NULL;
|
|
}
|
|
|
|
// Return whether a direct absolute static relocation needs to be applied.
|
|
// In cases where Scan::local() or Scan::global() has created
|
|
// a dynamic relocation other than R_386_RELATIVE, the addend
|
|
// of the relocation is carried in the data, and we must not
|
|
// apply the static relocation.
|
|
|
|
inline bool
|
|
Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
|
|
int ref_flags,
|
|
bool is_32bit)
|
|
{
|
|
// For local symbols, we will have created a non-RELATIVE dynamic
|
|
// relocation only if (a) the output is position independent,
|
|
// (b) the relocation is absolute (not pc- or segment-relative), and
|
|
// (c) the relocation is not 32 bits wide.
|
|
if (gsym == NULL)
|
|
return !(parameters->output_is_position_independent()
|
|
&& (ref_flags & Symbol::ABSOLUTE_REF)
|
|
&& !is_32bit);
|
|
|
|
// For global symbols, we use the same helper routines used in the
|
|
// scan pass. If we did not create a dynamic relocation, or if we
|
|
// created a RELATIVE dynamic relocation, we should apply the static
|
|
// relocation.
|
|
bool has_dyn = gsym->needs_dynamic_reloc(ref_flags);
|
|
bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF)
|
|
&& gsym->can_use_relative_reloc(ref_flags
|
|
& Symbol::FUNCTION_CALL);
|
|
return !has_dyn || is_rel;
|
|
}
|
|
|
|
// Perform a relocation.
|
|
|
|
inline bool
|
|
Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
|
|
Target_i386* target,
|
|
size_t relnum,
|
|
const elfcpp::Rel<32, false>& rel,
|
|
unsigned int r_type,
|
|
const Sized_symbol<32>* gsym,
|
|
const Symbol_value<32>* psymval,
|
|
unsigned char* view,
|
|
elfcpp::Elf_types<32>::Elf_Addr address,
|
|
section_size_type view_size)
|
|
{
|
|
if (this->skip_call_tls_get_addr_)
|
|
{
|
|
if (r_type != elfcpp::R_386_PLT32
|
|
|| gsym == NULL
|
|
|| strcmp(gsym->name(), "___tls_get_addr") != 0)
|
|
gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
|
|
_("missing expected TLS relocation"));
|
|
else
|
|
{
|
|
this->skip_call_tls_get_addr_ = false;
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// Pick the value to use for symbols defined in shared objects.
|
|
Symbol_value<32> symval;
|
|
bool is_nonpic = (r_type == elfcpp::R_386_PC8
|
|
|| r_type == elfcpp::R_386_PC16
|
|
|| r_type == elfcpp::R_386_PC32);
|
|
if (gsym != NULL
|
|
&& (gsym->is_from_dynobj()
|
|
|| (parameters->output_is_shared()
|
|
&& gsym->is_preemptible()))
|
|
&& gsym->has_plt_offset()
|
|
&& (!is_nonpic || !parameters->output_is_shared()))
|
|
{
|
|
symval.set_output_value(target->plt_section()->address()
|
|
+ gsym->plt_offset());
|
|
psymval = &symval;
|
|
}
|
|
|
|
const Sized_relobj<32, false>* object = relinfo->object;
|
|
|
|
// Get the GOT offset if needed.
|
|
// The GOT pointer points to the end of the GOT section.
|
|
// We need to subtract the size of the GOT section to get
|
|
// the actual offset to use in the relocation.
|
|
bool have_got_offset = false;
|
|
unsigned int got_offset = 0;
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_386_GOT32:
|
|
if (gsym != NULL)
|
|
{
|
|
gold_assert(gsym->has_got_offset());
|
|
got_offset = gsym->got_offset() - target->got_size();
|
|
}
|
|
else
|
|
{
|
|
unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
|
|
gold_assert(object->local_has_got_offset(r_sym));
|
|
got_offset = object->local_got_offset(r_sym) - target->got_size();
|
|
}
|
|
have_got_offset = true;
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_386_NONE:
|
|
case elfcpp::R_386_GNU_VTINHERIT:
|
|
case elfcpp::R_386_GNU_VTENTRY:
|
|
break;
|
|
|
|
case elfcpp::R_386_32:
|
|
if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true))
|
|
Relocate_functions<32, false>::rel32(view, object, psymval);
|
|
break;
|
|
|
|
case elfcpp::R_386_PC32:
|
|
{
|
|
int ref_flags = Symbol::NON_PIC_REF;
|
|
if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
|
|
ref_flags |= Symbol::FUNCTION_CALL;
|
|
if (should_apply_static_reloc(gsym, ref_flags, true))
|
|
Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_16:
|
|
if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false))
|
|
Relocate_functions<32, false>::rel16(view, object, psymval);
|
|
break;
|
|
|
|
case elfcpp::R_386_PC16:
|
|
{
|
|
int ref_flags = Symbol::NON_PIC_REF;
|
|
if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
|
|
ref_flags |= Symbol::FUNCTION_CALL;
|
|
if (should_apply_static_reloc(gsym, ref_flags, false))
|
|
Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_8:
|
|
if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false))
|
|
Relocate_functions<32, false>::rel8(view, object, psymval);
|
|
break;
|
|
|
|
case elfcpp::R_386_PC8:
|
|
{
|
|
int ref_flags = Symbol::NON_PIC_REF;
|
|
if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
|
|
ref_flags |= Symbol::FUNCTION_CALL;
|
|
if (should_apply_static_reloc(gsym, ref_flags, false))
|
|
Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_PLT32:
|
|
gold_assert(gsym == NULL
|
|
|| gsym->has_plt_offset()
|
|
|| gsym->final_value_is_known()
|
|
|| (gsym->is_defined()
|
|
&& !gsym->is_from_dynobj()
|
|
&& !gsym->is_preemptible()));
|
|
Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
|
|
break;
|
|
|
|
case elfcpp::R_386_GOT32:
|
|
gold_assert(have_got_offset);
|
|
Relocate_functions<32, false>::rel32(view, got_offset);
|
|
break;
|
|
|
|
case elfcpp::R_386_GOTOFF:
|
|
{
|
|
elfcpp::Elf_types<32>::Elf_Addr value;
|
|
value = (psymval->value(object, 0)
|
|
- target->got_plt_section()->address());
|
|
Relocate_functions<32, false>::rel32(view, value);
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_GOTPC:
|
|
{
|
|
elfcpp::Elf_types<32>::Elf_Addr value;
|
|
value = target->got_plt_section()->address();
|
|
Relocate_functions<32, false>::pcrel32(view, value, address);
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_COPY:
|
|
case elfcpp::R_386_GLOB_DAT:
|
|
case elfcpp::R_386_JUMP_SLOT:
|
|
case elfcpp::R_386_RELATIVE:
|
|
// These are outstanding tls relocs, which are unexpected when
|
|
// linking.
|
|
case elfcpp::R_386_TLS_TPOFF:
|
|
case elfcpp::R_386_TLS_DTPMOD32:
|
|
case elfcpp::R_386_TLS_DTPOFF32:
|
|
case elfcpp::R_386_TLS_TPOFF32:
|
|
case elfcpp::R_386_TLS_DESC:
|
|
gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
|
|
_("unexpected reloc %u in object file"),
|
|
r_type);
|
|
break;
|
|
|
|
// These are initial tls relocs, which are expected when
|
|
// linking.
|
|
case elfcpp::R_386_TLS_GD: // Global-dynamic
|
|
case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
|
|
case elfcpp::R_386_TLS_DESC_CALL:
|
|
case elfcpp::R_386_TLS_LDM: // Local-dynamic
|
|
case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
|
|
case elfcpp::R_386_TLS_IE: // Initial-exec
|
|
case elfcpp::R_386_TLS_IE_32:
|
|
case elfcpp::R_386_TLS_GOTIE:
|
|
case elfcpp::R_386_TLS_LE: // Local-exec
|
|
case elfcpp::R_386_TLS_LE_32:
|
|
this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
|
|
view, address, view_size);
|
|
break;
|
|
|
|
case elfcpp::R_386_32PLT:
|
|
case elfcpp::R_386_TLS_GD_32:
|
|
case elfcpp::R_386_TLS_GD_PUSH:
|
|
case elfcpp::R_386_TLS_GD_CALL:
|
|
case elfcpp::R_386_TLS_GD_POP:
|
|
case elfcpp::R_386_TLS_LDM_32:
|
|
case elfcpp::R_386_TLS_LDM_PUSH:
|
|
case elfcpp::R_386_TLS_LDM_CALL:
|
|
case elfcpp::R_386_TLS_LDM_POP:
|
|
case elfcpp::R_386_USED_BY_INTEL_200:
|
|
default:
|
|
gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
|
|
_("unsupported reloc %u"),
|
|
r_type);
|
|
break;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
// Perform a TLS relocation.
|
|
|
|
inline void
|
|
Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
|
|
Target_i386* target,
|
|
size_t relnum,
|
|
const elfcpp::Rel<32, false>& rel,
|
|
unsigned int r_type,
|
|
const Sized_symbol<32>* gsym,
|
|
const Symbol_value<32>* psymval,
|
|
unsigned char* view,
|
|
elfcpp::Elf_types<32>::Elf_Addr,
|
|
section_size_type view_size)
|
|
{
|
|
Output_segment* tls_segment = relinfo->layout->tls_segment();
|
|
|
|
const Sized_relobj<32, false>* object = relinfo->object;
|
|
|
|
elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
|
|
|
|
const bool is_final = (gsym == NULL
|
|
? !parameters->output_is_position_independent()
|
|
: gsym->final_value_is_known());
|
|
const tls::Tls_optimization optimized_type
|
|
= Target_i386::optimize_tls_reloc(is_final, r_type);
|
|
switch (r_type)
|
|
{
|
|
case elfcpp::R_386_TLS_GD: // Global-dynamic
|
|
if (optimized_type == tls::TLSOPT_TO_LE)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
this->tls_gd_to_le(relinfo, relnum, tls_segment,
|
|
rel, r_type, value, view,
|
|
view_size);
|
|
break;
|
|
}
|
|
else
|
|
{
|
|
unsigned int got_offset;
|
|
if (gsym != NULL)
|
|
{
|
|
gold_assert(gsym->has_tls_got_offset(true));
|
|
got_offset = gsym->tls_got_offset(true) - target->got_size();
|
|
}
|
|
else
|
|
{
|
|
unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
|
|
gold_assert(object->local_has_tls_got_offset(r_sym, true));
|
|
got_offset = (object->local_tls_got_offset(r_sym, true)
|
|
- target->got_size());
|
|
}
|
|
if (optimized_type == tls::TLSOPT_TO_IE)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
|
|
got_offset, view, view_size);
|
|
break;
|
|
}
|
|
else if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Relocate the field with the offset of the pair of GOT
|
|
// entries.
|
|
Relocate_functions<32, false>::rel32(view, got_offset);
|
|
break;
|
|
}
|
|
}
|
|
gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
|
|
_("unsupported reloc %u"),
|
|
r_type);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
|
|
case elfcpp::R_386_TLS_DESC_CALL:
|
|
gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
|
|
_("unsupported reloc %u"),
|
|
r_type);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_LDM: // Local-dynamic
|
|
if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
|
|
{
|
|
gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
|
|
_("both SUN and GNU model "
|
|
"TLS relocations"));
|
|
break;
|
|
}
|
|
this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
|
|
if (optimized_type == tls::TLSOPT_TO_LE)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
|
|
value, view, view_size);
|
|
break;
|
|
}
|
|
else if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Relocate the field with the offset of the GOT entry for
|
|
// the module index.
|
|
unsigned int got_offset;
|
|
got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
|
|
- target->got_size());
|
|
Relocate_functions<32, false>::rel32(view, got_offset);
|
|
break;
|
|
}
|
|
gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
|
|
_("unsupported reloc %u"),
|
|
r_type);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
|
|
// This reloc can appear in debugging sections, in which case we
|
|
// won't see the TLS_LDM reloc. The local_dynamic_type field
|
|
// tells us this.
|
|
if (optimized_type == tls::TLSOPT_TO_LE)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
value -= tls_segment->memsz();
|
|
}
|
|
Relocate_functions<32, false>::rel32(view, value);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_IE: // Initial-exec
|
|
case elfcpp::R_386_TLS_GOTIE:
|
|
case elfcpp::R_386_TLS_IE_32:
|
|
if (optimized_type == tls::TLSOPT_TO_LE)
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
|
|
rel, r_type, value, view,
|
|
view_size);
|
|
break;
|
|
}
|
|
else if (optimized_type == tls::TLSOPT_NONE)
|
|
{
|
|
// Relocate the field with the offset of the GOT entry for
|
|
// the tp-relative offset of the symbol.
|
|
unsigned int got_offset;
|
|
if (gsym != NULL)
|
|
{
|
|
gold_assert(gsym->has_got_offset());
|
|
got_offset = gsym->got_offset();
|
|
}
|
|
else
|
|
{
|
|
unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
|
|
gold_assert(object->local_has_got_offset(r_sym));
|
|
got_offset = object->local_got_offset(r_sym);
|
|
}
|
|
// For the R_386_TLS_IE relocation, we need to apply the
|
|
// absolute address of the GOT entry.
|
|
if (r_type == elfcpp::R_386_TLS_IE)
|
|
got_offset += target->got_plt_section()->address();
|
|
// All GOT offsets are relative to the end of the GOT.
|
|
got_offset -= target->got_size();
|
|
Relocate_functions<32, false>::rel32(view, got_offset);
|
|
break;
|
|
}
|
|
gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
|
|
_("unsupported reloc %u"),
|
|
r_type);
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_LE: // Local-exec
|
|
// If we're creating a shared library, a dynamic relocation will
|
|
// have been created for this location, so do not apply it now.
|
|
if (!parameters->output_is_shared())
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
value -= tls_segment->memsz();
|
|
Relocate_functions<32, false>::rel32(view, value);
|
|
}
|
|
break;
|
|
|
|
case elfcpp::R_386_TLS_LE_32:
|
|
// If we're creating a shared library, a dynamic relocation will
|
|
// have been created for this location, so do not apply it now.
|
|
if (!parameters->output_is_shared())
|
|
{
|
|
gold_assert(tls_segment != NULL);
|
|
value = tls_segment->memsz() - value;
|
|
Relocate_functions<32, false>::rel32(view, value);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Do a relocation in which we convert a TLS General-Dynamic to a
|
|
// Local-Exec.
|
|
|
|
inline void
|
|
Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
|
|
size_t relnum,
|
|
Output_segment* tls_segment,
|
|
const elfcpp::Rel<32, false>& rel,
|
|
unsigned int,
|
|
elfcpp::Elf_types<32>::Elf_Addr value,
|
|
unsigned char* view,
|
|
section_size_type view_size)
|
|
{
|
|
// leal foo(,%reg,1),%eax; call ___tls_get_addr
|
|
// ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
|
|
// leal foo(%reg),%eax; call ___tls_get_addr
|
|
// ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
|
|
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
|
|
|
|
unsigned char op1 = view[-1];
|
|
unsigned char op2 = view[-2];
|
|
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
|
|
op2 == 0x8d || op2 == 0x04);
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
|
|
|
|
int roff = 5;
|
|
|
|
if (op2 == 0x04)
|
|
{
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
|
|
((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
|
|
memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
|
|
}
|
|
else
|
|
{
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
|
|
(op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
|
|
if (rel.get_r_offset() + 9 < view_size
|
|
&& view[9] == 0x90)
|
|
{
|
|
// There is a trailing nop. Use the size byte subl.
|
|
memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
|
|
roff = 6;
|
|
}
|
|
else
|
|
{
|
|
// Use the five byte subl.
|
|
memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
|
|
}
|
|
}
|
|
|
|
value = tls_segment->memsz() - value;
|
|
Relocate_functions<32, false>::rel32(view + roff, value);
|
|
|
|
// The next reloc should be a PLT32 reloc against __tls_get_addr.
|
|
// We can skip it.
|
|
this->skip_call_tls_get_addr_ = true;
|
|
}
|
|
|
|
// Do a relocation in which we convert a TLS General-Dynamic to an
|
|
// Initial-Exec.
|
|
|
|
inline void
|
|
Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
|
|
size_t relnum,
|
|
Output_segment* tls_segment,
|
|
const elfcpp::Rel<32, false>& rel,
|
|
unsigned int,
|
|
elfcpp::Elf_types<32>::Elf_Addr value,
|
|
unsigned char* view,
|
|
section_size_type view_size)
|
|
{
|
|
// leal foo(,%ebx,1),%eax; call ___tls_get_addr
|
|
// ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
|
|
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
|
|
|
|
unsigned char op1 = view[-1];
|
|
unsigned char op2 = view[-2];
|
|
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
|
|
op2 == 0x8d || op2 == 0x04);
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
|
|
|
|
int roff = 5;
|
|
|
|
// FIXME: For now, support only one form.
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
|
|
op1 == 0x8d && op2 == 0x04);
|
|
|
|
if (op2 == 0x04)
|
|
{
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
|
|
((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
|
|
memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
|
|
}
|
|
else
|
|
{
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
|
|
(op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
|
|
if (rel.get_r_offset() + 9 < view_size
|
|
&& view[9] == 0x90)
|
|
{
|
|
// FIXME: This is not the right instruction sequence.
|
|
// There is a trailing nop. Use the size byte subl.
|
|
memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
|
|
roff = 6;
|
|
}
|
|
else
|
|
{
|
|
// FIXME: This is not the right instruction sequence.
|
|
// Use the five byte subl.
|
|
memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
|
|
}
|
|
}
|
|
|
|
value = tls_segment->memsz() - value;
|
|
Relocate_functions<32, false>::rel32(view + roff, value);
|
|
|
|
// The next reloc should be a PLT32 reloc against __tls_get_addr.
|
|
// We can skip it.
|
|
this->skip_call_tls_get_addr_ = true;
|
|
}
|
|
|
|
// Do a relocation in which we convert a TLS Local-Dynamic to a
|
|
// Local-Exec.
|
|
|
|
inline void
|
|
Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
|
|
size_t relnum,
|
|
Output_segment*,
|
|
const elfcpp::Rel<32, false>& rel,
|
|
unsigned int,
|
|
elfcpp::Elf_types<32>::Elf_Addr,
|
|
unsigned char* view,
|
|
section_size_type view_size)
|
|
{
|
|
// leal foo(%reg), %eax; call ___tls_get_addr
|
|
// ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
|
|
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
|
|
|
|
// FIXME: Does this test really always pass?
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
|
|
view[-2] == 0x8d && view[-1] == 0x83);
|
|
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
|
|
|
|
memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
|
|
|
|
// The next reloc should be a PLT32 reloc against __tls_get_addr.
|
|
// We can skip it.
|
|
this->skip_call_tls_get_addr_ = true;
|
|
}
|
|
|
|
// Do a relocation in which we convert a TLS Initial-Exec to a
|
|
// Local-Exec.
|
|
|
|
inline void
|
|
Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
|
|
size_t relnum,
|
|
Output_segment* tls_segment,
|
|
const elfcpp::Rel<32, false>& rel,
|
|
unsigned int r_type,
|
|
elfcpp::Elf_types<32>::Elf_Addr value,
|
|
unsigned char* view,
|
|
section_size_type view_size)
|
|
{
|
|
// We have to actually change the instructions, which means that we
|
|
// need to examine the opcodes to figure out which instruction we
|
|
// are looking at.
|
|
if (r_type == elfcpp::R_386_TLS_IE)
|
|
{
|
|
// movl %gs:XX,%eax ==> movl $YY,%eax
|
|
// movl %gs:XX,%reg ==> movl $YY,%reg
|
|
// addl %gs:XX,%reg ==> addl $YY,%reg
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
|
|
|
|
unsigned char op1 = view[-1];
|
|
if (op1 == 0xa1)
|
|
{
|
|
// movl XX,%eax ==> movl $YY,%eax
|
|
view[-1] = 0xb8;
|
|
}
|
|
else
|
|
{
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
|
|
|
|
unsigned char op2 = view[-2];
|
|
if (op2 == 0x8b)
|
|
{
|
|
// movl XX,%reg ==> movl $YY,%reg
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
|
|
(op1 & 0xc7) == 0x05);
|
|
view[-2] = 0xc7;
|
|
view[-1] = 0xc0 | ((op1 >> 3) & 7);
|
|
}
|
|
else if (op2 == 0x03)
|
|
{
|
|
// addl XX,%reg ==> addl $YY,%reg
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
|
|
(op1 & 0xc7) == 0x05);
|
|
view[-2] = 0x81;
|
|
view[-1] = 0xc0 | ((op1 >> 3) & 7);
|
|
}
|
|
else
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
|
|
}
|
|
}
|
|
else
|
|
{
|
|
// subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
|
|
// movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
|
|
// addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
|
|
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
|
|
|
|
unsigned char op1 = view[-1];
|
|
unsigned char op2 = view[-2];
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
|
|
(op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
|
|
if (op2 == 0x8b)
|
|
{
|
|
// movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2
|
|
view[-2] = 0xc7;
|
|
view[-1] = 0xc0 | ((op1 >> 3) & 7);
|
|
}
|
|
else if (op2 == 0x2b)
|
|
{
|
|
// subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2
|
|
view[-2] = 0x81;
|
|
view[-1] = 0xe8 | ((op1 >> 3) & 7);
|
|
}
|
|
else if (op2 == 0x03)
|
|
{
|
|
// addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2
|
|
view[-2] = 0x81;
|
|
view[-1] = 0xc0 | ((op1 >> 3) & 7);
|
|
}
|
|
else
|
|
tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
|
|
}
|
|
|
|
value = tls_segment->memsz() - value;
|
|
if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
|
|
value = - value;
|
|
|
|
Relocate_functions<32, false>::rel32(view, value);
|
|
}
|
|
|
|
// Relocate section data.
|
|
|
|
void
|
|
Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
|
|
unsigned int sh_type,
|
|
const unsigned char* prelocs,
|
|
size_t reloc_count,
|
|
Output_section* output_section,
|
|
bool needs_special_offset_handling,
|
|
unsigned char* view,
|
|
elfcpp::Elf_types<32>::Elf_Addr address,
|
|
section_size_type view_size)
|
|
{
|
|
gold_assert(sh_type == elfcpp::SHT_REL);
|
|
|
|
gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
|
|
Target_i386::Relocate>(
|
|
relinfo,
|
|
this,
|
|
prelocs,
|
|
reloc_count,
|
|
output_section,
|
|
needs_special_offset_handling,
|
|
view,
|
|
address,
|
|
view_size);
|
|
}
|
|
|
|
// Return the value to use for a dynamic which requires special
|
|
// treatment. This is how we support equality comparisons of function
|
|
// pointers across shared library boundaries, as described in the
|
|
// processor specific ABI supplement.
|
|
|
|
uint64_t
|
|
Target_i386::do_dynsym_value(const Symbol* gsym) const
|
|
{
|
|
gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
|
|
return this->plt_section()->address() + gsym->plt_offset();
|
|
}
|
|
|
|
// Return a string used to fill a code section with nops to take up
|
|
// the specified length.
|
|
|
|
std::string
|
|
Target_i386::do_code_fill(section_size_type length)
|
|
{
|
|
if (length >= 16)
|
|
{
|
|
// Build a jmp instruction to skip over the bytes.
|
|
unsigned char jmp[5];
|
|
jmp[0] = 0xe9;
|
|
elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
|
|
return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
|
|
+ std::string(length - 5, '\0'));
|
|
}
|
|
|
|
// Nop sequences of various lengths.
|
|
const char nop1[1] = { 0x90 }; // nop
|
|
const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax
|
|
const char nop3[3] = { 0x8d, 0x76, 0x00 }; // leal 0(%esi),%esi
|
|
const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00}; // leal 0(%esi,1),%esi
|
|
const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26, // nop
|
|
0x00 }; // leal 0(%esi,1),%esi
|
|
const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
|
|
0x00, 0x00 };
|
|
const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
|
|
0x00, 0x00, 0x00 };
|
|
const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26, // nop
|
|
0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
|
|
const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc, // movl %esi,%esi
|
|
0x27, 0x00, 0x00, 0x00, // leal 0L(%edi,1),%edi
|
|
0x00 };
|
|
const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
|
|
0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
|
|
0x00, 0x00 };
|
|
const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
|
|
0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
|
|
0x00, 0x00, 0x00 };
|
|
const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
|
|
0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
|
|
0x00, 0x00, 0x00, 0x00 };
|
|
const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
|
|
0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
|
|
0x27, 0x00, 0x00, 0x00,
|
|
0x00 };
|
|
const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
|
|
0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
|
|
0xbc, 0x27, 0x00, 0x00,
|
|
0x00, 0x00 };
|
|
const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
|
|
0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
|
|
0x90, 0x90, 0x90, 0x90,
|
|
0x90, 0x90, 0x90 };
|
|
|
|
const char* nops[16] = {
|
|
NULL,
|
|
nop1, nop2, nop3, nop4, nop5, nop6, nop7,
|
|
nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
|
|
};
|
|
|
|
return std::string(nops[length], length);
|
|
}
|
|
|
|
// The selector for i386 object files.
|
|
|
|
class Target_selector_i386 : public Target_selector
|
|
{
|
|
public:
|
|
Target_selector_i386()
|
|
: Target_selector(elfcpp::EM_386, 32, false)
|
|
{ }
|
|
|
|
Target*
|
|
recognize(int machine, int osabi, int abiversion);
|
|
|
|
private:
|
|
Target_i386* target_;
|
|
};
|
|
|
|
// Recognize an i386 object file when we already know that the machine
|
|
// number is EM_386.
|
|
|
|
Target*
|
|
Target_selector_i386::recognize(int, int, int)
|
|
{
|
|
if (this->target_ == NULL)
|
|
this->target_ = new Target_i386();
|
|
return this->target_;
|
|
}
|
|
|
|
Target_selector_i386 target_selector_i386;
|
|
|
|
} // End anonymous namespace.
|