X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gold%2Fi386.cc;h=fe8341de727c341efe521c283e1c7fa0484b9363;hb=8f0a6da7a9e9d4b8258af20cfb5db072ace0ba86;hp=21dd57a2ed720df908ab768d77ea4ea56dcace65;hpb=75f65a3e309b8cd885c782f6af106d1e2a1876f6;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/i386.cc b/gold/i386.cc index 21dd57a2ed..fe8341de72 100644 --- a/gold/i386.cc +++ b/gold/i386.cc @@ -1,39 +1,2231 @@ // i386.cc -- i386 target support for gold. +// Copyright 2006, 2007 Free Software Foundation, Inc. +// Written by Ian Lance Taylor . + +// This file is part of gold. + +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 3 of the License, or +// (at your option) any later version. + +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, +// MA 02110-1301, USA. + #include "gold.h" + +#include + #include "elfcpp.h" +#include "parameters.h" +#include "reloc.h" +#include "i386.h" +#include "object.h" +#include "symtab.h" +#include "layout.h" +#include "output.h" #include "target.h" +#include "target-reloc.h" #include "target-select.h" +#include "tls.h" namespace { using namespace gold; +class Output_data_plt_i386; + // The i386 target class. +// TLS info comes from +// http://people.redhat.com/drepper/tls.pdf +// http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt class Target_i386 : public Sized_target<32, false> { public: + typedef Output_data_reloc Reloc_section; + Target_i386() - : Sized_target<32, false>(&i386_info) + : Sized_target<32, false>(&i386_info), + got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL), + copy_relocs_(NULL), dynbss_(NULL), got_mod_index_offset_(-1U) { } + // Scan the relocations to look for symbol adjustments. + void + 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); + + // Finalize the sections. + void + do_finalize_sections(Layout*); + + // Return the value to use for a dynamic which requires special + // treatment. + uint64_t + do_dynsym_value(const Symbol*) const; + + // Relocate a section. + void + relocate_section(const Relocate_info<32, false>*, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + bool needs_special_offset_handling, + unsigned char* view, + elfcpp::Elf_types<32>::Elf_Addr view_address, + section_size_type view_size); + + // Return a string used to fill a code section with nops. + std::string + do_code_fill(section_size_type length); + + // Return whether SYM is defined by the ABI. + bool + do_is_defined_by_abi(Symbol* sym) const + { return strcmp(sym->name(), "___tls_get_addr") == 0; } + + // Return the size of the GOT section. + section_size_type + got_size() + { + gold_assert(this->got_ != NULL); + return this->got_->data_size(); + } + private: + // The class which scans relocations. + struct Scan + { + inline void + local(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, + const elfcpp::Sym<32, false>& lsym); + + inline void + 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); + + static void + unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type); + + static void + unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type, + Symbol*); + }; + + // The class which implements relocation. + class Relocate + { + public: + Relocate() + : skip_call_tls_get_addr_(false), + local_dynamic_type_(LOCAL_DYNAMIC_NONE) + { } + + ~Relocate() + { + if (this->skip_call_tls_get_addr_) + { + // FIXME: This needs to specify the location somehow. + gold_error(_("missing expected TLS relocation")); + } + } + + // Return whether the static relocation needs to be applied. + inline bool + should_apply_static_reloc(const Sized_symbol<32>* gsym, + int ref_flags, + bool is_32bit); + + // Do a relocation. Return false if the caller should not issue + // any warnings about this relocation. + inline bool + relocate(const Relocate_info<32, false>*, Target_i386*, size_t relnum, + const elfcpp::Rel<32, false>&, + unsigned int r_type, const Sized_symbol<32>*, + const Symbol_value<32>*, + unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, + section_size_type); + + private: + // Do a TLS relocation. + inline void + relocate_tls(const Relocate_info<32, false>*, Target_i386* target, + size_t relnum, const elfcpp::Rel<32, false>&, + unsigned int r_type, const Sized_symbol<32>*, + const Symbol_value<32>*, + unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, + section_size_type); + + // Do a TLS General-Dynamic to Initial-Exec transition. + inline void + tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rel<32, false>&, unsigned int r_type, + elfcpp::Elf_types<32>::Elf_Addr value, + unsigned char* view, + section_size_type view_size); + + // Do a TLS General-Dynamic to Local-Exec transition. + inline void + tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rel<32, false>&, unsigned int r_type, + elfcpp::Elf_types<32>::Elf_Addr value, + unsigned char* view, + section_size_type view_size); + + // Do a TLS Local-Dynamic to Local-Exec transition. + inline void + tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rel<32, false>&, unsigned int r_type, + elfcpp::Elf_types<32>::Elf_Addr value, + unsigned char* view, + section_size_type view_size); + + // Do a TLS Initial-Exec to Local-Exec transition. + static inline void + tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rel<32, false>&, unsigned int r_type, + elfcpp::Elf_types<32>::Elf_Addr value, + unsigned char* view, + section_size_type view_size); + + // We need to keep track of which type of local dynamic relocation + // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly. + enum Local_dynamic_type + { + LOCAL_DYNAMIC_NONE, + LOCAL_DYNAMIC_SUN, + LOCAL_DYNAMIC_GNU + }; + + // This is set if we should skip the next reloc, which should be a + // PLT32 reloc against ___tls_get_addr. + bool skip_call_tls_get_addr_; + // The type of local dynamic relocation we have seen in the section + // being relocated, if any. + Local_dynamic_type local_dynamic_type_; + }; + + // Adjust TLS relocation type based on the options and whether this + // is a local symbol. + static tls::Tls_optimization + optimize_tls_reloc(bool is_final, int r_type); + + // Get the GOT section, creating it if necessary. + Output_data_got<32, false>* + got_section(Symbol_table*, Layout*); + + // Get the GOT PLT section. + Output_data_space* + got_plt_section() const + { + gold_assert(this->got_plt_ != NULL); + return this->got_plt_; + } + + // Create a PLT entry for a global symbol. + void + make_plt_entry(Symbol_table*, Layout*, Symbol*); + + // Create a GOT entry for the TLS module index. + unsigned int + got_mod_index_entry(Symbol_table* symtab, Layout* layout, + Sized_relobj<32, false>* object); + + // Get the PLT section. + const Output_data_plt_i386* + plt_section() const + { + gold_assert(this->plt_ != NULL); + return this->plt_; + } + + // Get the dynamic reloc section, creating it if necessary. + Reloc_section* + rel_dyn_section(Layout*); + + // Return true if the symbol may need a COPY relocation. + // References from an executable object to non-function symbols + // defined in a dynamic object may need a COPY relocation. + bool + may_need_copy_reloc(Symbol* gsym) + { + return (!parameters->output_is_shared() + && gsym->is_from_dynobj() + && gsym->type() != elfcpp::STT_FUNC); + } + + // Copy a relocation against a global symbol. + void + copy_reloc(const General_options*, Symbol_table*, Layout*, + Sized_relobj<32, false>*, unsigned int, + Output_section*, Symbol*, const elfcpp::Rel<32, false>&); + + // Information about this specific target which we pass to the + // general Target structure. static const Target::Target_info i386_info; + + // The GOT section. + Output_data_got<32, false>* got_; + // The PLT section. + Output_data_plt_i386* plt_; + // The GOT PLT section. + Output_data_space* got_plt_; + // The dynamic reloc section. + Reloc_section* rel_dyn_; + // Relocs saved to avoid a COPY reloc. + Copy_relocs<32, false>* copy_relocs_; + // Space for variables copied with a COPY reloc. + Output_data_space* dynbss_; + // Offset of the GOT entry for the TLS module index; + unsigned int got_mod_index_offset_; }; const Target::Target_info Target_i386::i386_info = { - 32, // size - false, // is_big_endian - false, // has_make_symbol - false, // has_resolve, - 0x08048000, // text_segment_address, - 0x1000, // abi_pagesize - 0x1000 // common_pagesize + 32, // size + false, // is_big_endian + elfcpp::EM_386, // machine_code + false, // has_make_symbol + false, // has_resolve + true, // has_code_fill + true, // is_default_stack_executable + "/usr/lib/libc.so.1", // dynamic_linker + 0x08048000, // default_text_segment_address + 0x1000, // abi_pagesize + 0x1000 // common_pagesize +}; + +// Get the GOT section, creating it if necessary. + +Output_data_got<32, false>* +Target_i386::got_section(Symbol_table* symtab, Layout* layout) +{ + if (this->got_ == NULL) + { + gold_assert(symtab != NULL && layout != NULL); + + this->got_ = new Output_data_got<32, false>(); + + layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, + elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, + this->got_); + + // The old GNU linker creates a .got.plt section. We just + // create another set of data in the .got section. Note that we + // always create a PLT if we create a GOT, although the PLT + // might be empty. + this->got_plt_ = new Output_data_space(4); + layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, + elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, + this->got_plt_); + + // The first three entries are reserved. + this->got_plt_->set_current_data_size(3 * 4); + + // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. + symtab->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL, + this->got_plt_, + 0, 0, elfcpp::STT_OBJECT, + elfcpp::STB_LOCAL, + elfcpp::STV_HIDDEN, 0, + false, false); + } + + return this->got_; +} + +// Get the dynamic reloc section, creating it if necessary. + +Target_i386::Reloc_section* +Target_i386::rel_dyn_section(Layout* layout) +{ + if (this->rel_dyn_ == NULL) + { + gold_assert(layout != NULL); + this->rel_dyn_ = new Reloc_section(); + layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL, + elfcpp::SHF_ALLOC, this->rel_dyn_); + } + return this->rel_dyn_; +} + +// A class to handle the PLT data. + +class Output_data_plt_i386 : public Output_section_data +{ + public: + typedef Output_data_reloc Reloc_section; + + Output_data_plt_i386(Layout*, Output_data_space*); + + // Add an entry to the PLT. + void + add_entry(Symbol* gsym); + + // Return the .rel.plt section data. + const Reloc_section* + rel_plt() const + { return this->rel_; } + + protected: + void + do_adjust_output_section(Output_section* os); + + private: + // The size of an entry in the PLT. + static const int plt_entry_size = 16; + + // The first entry in the PLT for an executable. + static unsigned char exec_first_plt_entry[plt_entry_size]; + + // The first entry in the PLT for a shared object. + static unsigned char dyn_first_plt_entry[plt_entry_size]; + + // Other entries in the PLT for an executable. + static unsigned char exec_plt_entry[plt_entry_size]; + + // Other entries in the PLT for a shared object. + static unsigned char dyn_plt_entry[plt_entry_size]; + + // Set the final size. + void + set_final_data_size() + { this->set_data_size((this->count_ + 1) * plt_entry_size); } + + // Write out the PLT data. + void + do_write(Output_file*); + + // The reloc section. + Reloc_section* rel_; + // The .got.plt section. + Output_data_space* got_plt_; + // The number of PLT entries. + unsigned int count_; +}; + +// Create the PLT section. The ordinary .got section is an argument, +// since we need to refer to the start. We also create our own .got +// section just for PLT entries. + +Output_data_plt_i386::Output_data_plt_i386(Layout* layout, + Output_data_space* got_plt) + : Output_section_data(4), got_plt_(got_plt), count_(0) +{ + this->rel_ = new Reloc_section(); + layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, + elfcpp::SHF_ALLOC, this->rel_); +} + +void +Output_data_plt_i386::do_adjust_output_section(Output_section* os) +{ + // UnixWare sets the entsize of .plt to 4, and so does the old GNU + // linker, and so do we. + os->set_entsize(4); +} + +// Add an entry to the PLT. + +void +Output_data_plt_i386::add_entry(Symbol* gsym) +{ + gold_assert(!gsym->has_plt_offset()); + + // Note that when setting the PLT offset we skip the initial + // reserved PLT entry. + gsym->set_plt_offset((this->count_ + 1) * plt_entry_size); + + ++this->count_; + + section_offset_type got_offset = this->got_plt_->current_data_size(); + + // Every PLT entry needs a GOT entry which points back to the PLT + // entry (this will be changed by the dynamic linker, normally + // lazily when the function is called). + this->got_plt_->set_current_data_size(got_offset + 4); + + // Every PLT entry needs a reloc. + gsym->set_needs_dynsym_entry(); + this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_, + got_offset); + + // Note that we don't need to save the symbol. The contents of the + // PLT are independent of which symbols are used. The symbols only + // appear in the relocations. +} + +// The first entry in the PLT for an executable. + +unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] = +{ + 0xff, 0x35, // pushl contents of memory address + 0, 0, 0, 0, // replaced with address of .got + 4 + 0xff, 0x25, // jmp indirect + 0, 0, 0, 0, // replaced with address of .got + 8 + 0, 0, 0, 0 // unused +}; + +// The first entry in the PLT for a shared object. + +unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] = +{ + 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx) + 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx) + 0, 0, 0, 0 // unused +}; + +// Subsequent entries in the PLT for an executable. + +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(pov - oview) == oview_size); + gold_assert(static_cast(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(this, 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(&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 @@ -44,16 +2236,21 @@ public: { } Target* - recognize(int machine, int osabi, int abiversion) const; + 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) const +Target_selector_i386::recognize(int, int, int) { - return new Target_i386(); + if (this->target_ == NULL) + this->target_ = new Target_i386(); + return this->target_; } Target_selector_i386 target_selector_i386;