X-Git-Url: https://oss.titaniummirror.com/gitweb?p=msp430-binutils.git;a=blobdiff_plain;f=gold%2Fx86_64.cc;fp=gold%2Fx86_64.cc;h=3562065611b56bb59bcb6b859854bba6807b448b;hp=0000000000000000000000000000000000000000;hb=d5da4f291af551c0b8b79e1d4a9b173d60e5c10e;hpb=7b5ea4fcdf2819e070665ab5610f8b48e3867c10 diff --git a/gold/x86_64.cc b/gold/x86_64.cc new file mode 100644 index 0000000..3562065 --- /dev/null +++ b/gold/x86_64.cc @@ -0,0 +1,2747 @@ +// x86_64.cc -- x86_64 target support for gold. + +// Copyright 2006, 2007, 2008, 2009 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 "x86_64.h" +#include "object.h" +#include "symtab.h" +#include "layout.h" +#include "output.h" +#include "copy-relocs.h" +#include "target.h" +#include "target-reloc.h" +#include "target-select.h" +#include "tls.h" +#include "freebsd.h" +#include "gc.h" + +namespace +{ + +using namespace gold; + +class Output_data_plt_x86_64; + +// The x86_64 target class. +// See the ABI at +// http://www.x86-64.org/documentation/abi.pdf +// 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_x86_64 : public Target_freebsd<64, false> +{ + public: + // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures + // uses only Elf64_Rela relocation entries with explicit addends." + typedef Output_data_reloc Reloc_section; + + Target_x86_64() + : Target_freebsd<64, false>(&x86_64_info), + got_(NULL), plt_(NULL), got_plt_(NULL), rela_dyn_(NULL), + copy_relocs_(elfcpp::R_X86_64_COPY), dynbss_(NULL), + got_mod_index_offset_(-1U), tls_base_symbol_defined_(false) + { } + + // Hook for a new output section. + void + do_new_output_section(Output_section*) const; + + // Scan the relocations to look for symbol adjustments. + void + gc_process_relocs(const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<64, false>* object, + unsigned int data_shndx, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + bool needs_special_offset_handling, + size_t local_symbol_count, + const unsigned char* plocal_symbols); + + // Scan the relocations to look for symbol adjustments. + void + scan_relocs(const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<64, false>* object, + unsigned int data_shndx, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + bool needs_special_offset_handling, + size_t local_symbol_count, + const unsigned char* plocal_symbols); + + // 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<64, 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<64>::Elf_Addr view_address, + section_size_type view_size, + const Reloc_symbol_changes*); + + // Scan the relocs during a relocatable link. + void + scan_relocatable_relocs(const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<64, false>* object, + unsigned int data_shndx, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + bool needs_special_offset_handling, + size_t local_symbol_count, + const unsigned char* plocal_symbols, + Relocatable_relocs*); + + // Relocate a section during a relocatable link. + void + relocate_for_relocatable(const Relocate_info<64, false>*, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + off_t offset_in_output_section, + const Relocatable_relocs*, + unsigned char* view, + elfcpp::Elf_types<64>::Elf_Addr view_address, + section_size_type view_size, + unsigned char* reloc_view, + section_size_type reloc_view_size); + + // Return a string used to fill a code section with nops. + std::string + do_code_fill(section_size_type length) const; + + // Return whether SYM is defined by the ABI. + bool + do_is_defined_by_abi(const Symbol* sym) const + { return strcmp(sym->name(), "__tls_get_addr") == 0; } + + // Adjust -fstack-split code which calls non-stack-split code. + void + do_calls_non_split(Relobj* object, unsigned int shndx, + section_offset_type fnoffset, section_size_type fnsize, + unsigned char* view, section_size_type view_size, + std::string* from, std::string* to) const; + + // Return the size of the GOT section. + section_size_type + got_size() + { + gold_assert(this->got_ != NULL); + return this->got_->data_size(); + } + + private: + // The class which scans relocations. + class Scan + { + public: + Scan() + : issued_non_pic_error_(false) + { } + + inline void + local(const General_options& options, Symbol_table* symtab, + Layout* layout, Target_x86_64* target, + Sized_relobj<64, false>* object, + unsigned int data_shndx, + Output_section* output_section, + const elfcpp::Rela<64, false>& reloc, unsigned int r_type, + const elfcpp::Sym<64, false>& lsym); + + inline void + global(const General_options& options, Symbol_table* symtab, + Layout* layout, Target_x86_64* target, + Sized_relobj<64, false>* object, + unsigned int data_shndx, + Output_section* output_section, + const elfcpp::Rela<64, false>& reloc, unsigned int r_type, + Symbol* gsym); + + private: + static void + unsupported_reloc_local(Sized_relobj<64, false>*, unsigned int r_type); + + static void + unsupported_reloc_global(Sized_relobj<64, false>*, unsigned int r_type, + Symbol*); + + void + check_non_pic(Relobj*, unsigned int r_type); + + // Whether we have issued an error about a non-PIC compilation. + bool issued_non_pic_error_; + }; + + // The class which implements relocation. + class Relocate + { + public: + Relocate() + : skip_call_tls_get_addr_(false), saw_tls_block_reloc_(false) + { } + + ~Relocate() + { + if (this->skip_call_tls_get_addr_) + { + // FIXME: This needs to specify the location somehow. + gold_error(_("missing expected TLS relocation")); + } + } + + // Do a relocation. Return false if the caller should not issue + // any warnings about this relocation. + inline bool + relocate(const Relocate_info<64, false>*, Target_x86_64*, Output_section*, + size_t relnum, const elfcpp::Rela<64, false>&, + unsigned int r_type, const Sized_symbol<64>*, + const Symbol_value<64>*, + unsigned char*, elfcpp::Elf_types<64>::Elf_Addr, + section_size_type); + + private: + // Do a TLS relocation. + inline void + relocate_tls(const Relocate_info<64, false>*, Target_x86_64*, + size_t relnum, const elfcpp::Rela<64, false>&, + unsigned int r_type, const Sized_symbol<64>*, + const Symbol_value<64>*, + unsigned char*, elfcpp::Elf_types<64>::Elf_Addr, + section_size_type); + + // Do a TLS General-Dynamic to Initial-Exec transition. + inline void + tls_gd_to_ie(const Relocate_info<64, false>*, size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rela<64, false>&, unsigned int r_type, + elfcpp::Elf_types<64>::Elf_Addr value, + unsigned char* view, + elfcpp::Elf_types<64>::Elf_Addr, + section_size_type view_size); + + // Do a TLS General-Dynamic to Local-Exec transition. + inline void + tls_gd_to_le(const Relocate_info<64, false>*, size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rela<64, false>&, unsigned int r_type, + elfcpp::Elf_types<64>::Elf_Addr value, + unsigned char* view, + section_size_type view_size); + + // Do a TLSDESC-style General-Dynamic to Initial-Exec transition. + inline void + tls_desc_gd_to_ie(const Relocate_info<64, false>*, size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rela<64, false>&, unsigned int r_type, + elfcpp::Elf_types<64>::Elf_Addr value, + unsigned char* view, + elfcpp::Elf_types<64>::Elf_Addr, + section_size_type view_size); + + // Do a TLSDESC-style General-Dynamic to Local-Exec transition. + inline void + tls_desc_gd_to_le(const Relocate_info<64, false>*, size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rela<64, false>&, unsigned int r_type, + elfcpp::Elf_types<64>::Elf_Addr value, + unsigned char* view, + section_size_type view_size); + + // Do a TLS Local-Dynamic to Local-Exec transition. + inline void + tls_ld_to_le(const Relocate_info<64, false>*, size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rela<64, false>&, unsigned int r_type, + elfcpp::Elf_types<64>::Elf_Addr value, + unsigned char* view, + section_size_type view_size); + + // Do a TLS Initial-Exec to Local-Exec transition. + static inline void + tls_ie_to_le(const Relocate_info<64, false>*, size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rela<64, false>&, unsigned int r_type, + elfcpp::Elf_types<64>::Elf_Addr value, + unsigned char* view, + section_size_type view_size); + + // This is set if we should skip the next reloc, which should be a + // PLT32 reloc against ___tls_get_addr. + bool skip_call_tls_get_addr_; + + // This is set if we see a relocation which could load the address + // of the TLS block. Whether we see such a relocation determines + // how we handle the R_X86_64_DTPOFF32 relocation, which is used + // in debugging sections. + bool saw_tls_block_reloc_; + }; + + // A class which returns the size required for a relocation type, + // used while scanning relocs during a relocatable link. + class Relocatable_size_for_reloc + { + public: + unsigned int + get_size_for_reloc(unsigned int, Relobj*); + }; + + // Adjust TLS relocation type based on the options and whether this + // is a local symbol. + static tls::Tls_optimization + optimize_tls_reloc(bool is_final, int r_type); + + // Get the GOT section, creating it if necessary. + Output_data_got<64, false>* + got_section(Symbol_table*, Layout*); + + // Get the GOT PLT section. + Output_data_space* + got_plt_section() const + { + gold_assert(this->got_plt_ != NULL); + return this->got_plt_; + } + + // Create the PLT section. + void + make_plt_section(Symbol_table* symtab, Layout* layout); + + // Create a PLT entry for a global symbol. + void + make_plt_entry(Symbol_table*, Layout*, Symbol*); + + // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. + void + define_tls_base_symbol(Symbol_table*, Layout*); + + // Create the reserved PLT and GOT entries for the TLS descriptor resolver. + void + reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout); + + // Create a GOT entry for the TLS module index. + unsigned int + got_mod_index_entry(Symbol_table* symtab, Layout* layout, + Sized_relobj<64, false>* object); + + // Get the PLT section. + Output_data_plt_x86_64* + plt_section() const + { + gold_assert(this->plt_ != NULL); + return this->plt_; + } + + // Get the dynamic reloc section, creating it if necessary. + Reloc_section* + rela_dyn_section(Layout*); + + // Add a potential copy relocation. + void + copy_reloc(Symbol_table* symtab, Layout* layout, + Sized_relobj<64, false>* object, + unsigned int shndx, Output_section* output_section, + Symbol* sym, const elfcpp::Rela<64, false>& reloc) + { + this->copy_relocs_.copy_reloc(symtab, layout, + symtab->get_sized_symbol<64>(sym), + object, shndx, output_section, + reloc, this->rela_dyn_section(layout)); + } + + // Information about this specific target which we pass to the + // general Target structure. + static const Target::Target_info x86_64_info; + + enum Got_type + { + GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol + GOT_TYPE_TLS_OFFSET = 1, // GOT entry for TLS offset + GOT_TYPE_TLS_PAIR = 2, // GOT entry for TLS module/offset pair + GOT_TYPE_TLS_DESC = 3 // GOT entry for TLS_DESC pair + }; + + // The GOT section. + Output_data_got<64, false>* got_; + // The PLT section. + Output_data_plt_x86_64* plt_; + // The GOT PLT section. + Output_data_space* got_plt_; + // The dynamic reloc section. + Reloc_section* rela_dyn_; + // Relocs saved to avoid a COPY reloc. + Copy_relocs 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_; + // True if the _TLS_MODULE_BASE_ symbol has been defined. + bool tls_base_symbol_defined_; +}; + +const Target::Target_info Target_x86_64::x86_64_info = +{ + 64, // size + false, // is_big_endian + elfcpp::EM_X86_64, // machine_code + false, // has_make_symbol + false, // has_resolve + true, // has_code_fill + true, // is_default_stack_executable + '\0', // wrap_char + "/lib/ld64.so.1", // program interpreter + 0x400000, // default_text_segment_address + 0x1000, // abi_pagesize (overridable by -z max-page-size) + 0x1000, // common_pagesize (overridable by -z common-page-size) + elfcpp::SHN_UNDEF, // small_common_shndx + elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx + 0, // small_common_section_flags + elfcpp::SHF_X86_64_LARGE // large_common_section_flags +}; + +// This is called when a new output section is created. This is where +// we handle the SHF_X86_64_LARGE. + +void +Target_x86_64::do_new_output_section(Output_section *os) const +{ + if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0) + os->set_is_large_section(); +} + +// Get the GOT section, creating it if necessary. + +Output_data_got<64, false>* +Target_x86_64::got_section(Symbol_table* symtab, Layout* layout) +{ + if (this->got_ == NULL) + { + gold_assert(symtab != NULL && layout != NULL); + + this->got_ = new Output_data_got<64, false>(); + + Output_section* os; + os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_WRITE), + this->got_); + os->set_is_relro(); + + // 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(8, "** GOT PLT"); + os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_WRITE), + this->got_plt_); + os->set_is_relro(); + + // The first three entries are reserved. + this->got_plt_->set_current_data_size(3 * 8); + + // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. + symtab->define_in_output_data("_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_x86_64::Reloc_section* +Target_x86_64::rela_dyn_section(Layout* layout) +{ + if (this->rela_dyn_ == NULL) + { + gold_assert(layout != NULL); + this->rela_dyn_ = new Reloc_section(parameters->options().combreloc()); + layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA, + elfcpp::SHF_ALLOC, this->rela_dyn_); + } + return this->rela_dyn_; +} + +// A class to handle the PLT data. + +class Output_data_plt_x86_64 : public Output_section_data +{ + public: + typedef Output_data_reloc Reloc_section; + + Output_data_plt_x86_64(Layout*, Output_data_got<64, false>*, + Output_data_space*); + + // Add an entry to the PLT. + void + add_entry(Symbol* gsym); + + // Add the reserved TLSDESC_PLT entry to the PLT. + void + reserve_tlsdesc_entry(unsigned int got_offset) + { this->tlsdesc_got_offset_ = got_offset; } + + // Return true if a TLSDESC_PLT entry has been reserved. + bool + has_tlsdesc_entry() const + { return this->tlsdesc_got_offset_ != -1U; } + + // Return the GOT offset for the reserved TLSDESC_PLT entry. + unsigned int + get_tlsdesc_got_offset() const + { return this->tlsdesc_got_offset_; } + + // Return the offset of the reserved TLSDESC_PLT entry. + unsigned int + get_tlsdesc_plt_offset() const + { return (this->count_ + 1) * plt_entry_size; } + + // Return the .rel.plt section data. + const Reloc_section* + rel_plt() const + { return this->rel_; } + + protected: + void + do_adjust_output_section(Output_section* os); + + // Write to a map file. + void + do_print_to_mapfile(Mapfile* mapfile) const + { mapfile->print_output_data(this, _("** PLT")); } + + private: + // The size of an entry in the PLT. + static const int plt_entry_size = 16; + + // The first entry in the PLT. + // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same + // procedure linkage table for both programs and shared objects." + static unsigned char first_plt_entry[plt_entry_size]; + + // Other entries in the PLT for an executable. + static unsigned char plt_entry[plt_entry_size]; + + // The reserved TLSDESC entry in the PLT for an executable. + static unsigned char tlsdesc_plt_entry[plt_entry_size]; + + // Set the final size. + void + set_final_data_size(); + + // Write out the PLT data. + void + do_write(Output_file*); + + // The reloc section. + Reloc_section* rel_; + // The .got section. + Output_data_got<64, false>* got_; + // The .got.plt section. + Output_data_space* got_plt_; + // The number of PLT entries. + unsigned int count_; + // Offset of the reserved TLSDESC_GOT entry when needed. + unsigned int tlsdesc_got_offset_; +}; + +// 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_x86_64::Output_data_plt_x86_64(Layout* layout, + Output_data_got<64, false>* got, + Output_data_space* got_plt) + : Output_section_data(8), got_(got), got_plt_(got_plt), count_(0), + tlsdesc_got_offset_(-1U) +{ + this->rel_ = new Reloc_section(false); + layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, + elfcpp::SHF_ALLOC, this->rel_); +} + +void +Output_data_plt_x86_64::do_adjust_output_section(Output_section* os) +{ + os->set_entsize(plt_entry_size); +} + +// Add an entry to the PLT. + +void +Output_data_plt_x86_64::add_entry(Symbol* gsym) +{ + gold_assert(!gsym->has_plt_offset()); + + // 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 + 8); + + // Every PLT entry needs a reloc. + gsym->set_needs_dynsym_entry(); + this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_, + got_offset, 0); + + // 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. +} + +// Set the final size. +void +Output_data_plt_x86_64::set_final_data_size() +{ + unsigned int count = this->count_; + if (this->has_tlsdesc_entry()) + ++count; + this->set_data_size((count + 1) * plt_entry_size); +} + +// The first entry in the PLT for an executable. + +unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] = +{ + // From AMD64 ABI Draft 0.98, page 76 + 0xff, 0x35, // pushq contents of memory address + 0, 0, 0, 0, // replaced with address of .got + 8 + 0xff, 0x25, // jmp indirect + 0, 0, 0, 0, // replaced with address of .got + 16 + 0x90, 0x90, 0x90, 0x90 // noop (x4) +}; + +// Subsequent entries in the PLT for an executable. + +unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] = +{ + // From AMD64 ABI Draft 0.98, page 76 + 0xff, 0x25, // jmpq indirect + 0, 0, 0, 0, // replaced with address of symbol in .got + 0x68, // pushq immediate + 0, 0, 0, 0, // replaced with offset into relocation table + 0xe9, // jmpq relative + 0, 0, 0, 0 // replaced with offset to start of .plt +}; + +// The reserved TLSDESC entry in the PLT for an executable. + +unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] = +{ + // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32 + // and AMD64/EM64T", Version 0.9.4 (2005-10-10). + 0xff, 0x35, // pushq x(%rip) + 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8) + 0xff, 0x25, // jmpq *y(%rip) + 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry + 0x0f, 0x1f, // nop + 0x40, 0 +}; + +// Write out the PLT. This uses the hand-coded instructions above, +// and adjusts them as needed. This is specified by the AMD64 ABI. + +void +Output_data_plt_x86_64::do_write(Output_file* of) +{ + const off_t offset = this->offset(); + const section_size_type oview_size = + convert_to_section_size_type(this->data_size()); + unsigned char* const oview = of->get_output_view(offset, oview_size); + + const off_t got_file_offset = this->got_plt_->offset(); + const section_size_type got_size = + convert_to_section_size_type(this->got_plt_->data_size()); + unsigned char* const got_view = of->get_output_view(got_file_offset, + got_size); + + unsigned char* pov = oview; + + // The base address of the .plt section. + elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address(); + // The base address of the .got section. + elfcpp::Elf_types<64>::Elf_Addr got_base = this->got_->address(); + // The base address of the PLT portion of the .got section, + // which is where the GOT pointer will point, and where the + // three reserved GOT entries are located. + elfcpp::Elf_types<64>::Elf_Addr got_address = this->got_plt_->address(); + + memcpy(pov, first_plt_entry, plt_entry_size); + // We do a jmp relative to the PC at the end of this instruction. + elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, + (got_address + 8 + - (plt_address + 6))); + elfcpp::Swap<32, false>::writeval(pov + 8, + (got_address + 16 + - (plt_address + 12))); + pov += plt_entry_size; + + unsigned char* got_pov = got_view; + + memset(got_pov, 0, 24); + got_pov += 24; + + unsigned int plt_offset = plt_entry_size; + unsigned int got_offset = 24; + const unsigned int count = this->count_; + for (unsigned int plt_index = 0; + plt_index < count; + ++plt_index, + pov += plt_entry_size, + got_pov += 8, + plt_offset += plt_entry_size, + got_offset += 8) + { + // Set and adjust the PLT entry itself. + memcpy(pov, plt_entry, plt_entry_size); + elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, + (got_address + got_offset + - (plt_address + plt_offset + + 6))); + + elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index); + elfcpp::Swap<32, false>::writeval(pov + 12, + - (plt_offset + plt_entry_size)); + + // Set the entry in the GOT. + elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6); + } + + if (this->has_tlsdesc_entry()) + { + // Set and adjust the reserved TLSDESC PLT entry. + unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset(); + memcpy(pov, tlsdesc_plt_entry, plt_entry_size); + elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, + (got_address + 8 + - (plt_address + plt_offset + + 6))); + elfcpp::Swap_unaligned<32, false>::writeval(pov + 8, + (got_base + + tlsdesc_got_offset + - (plt_address + plt_offset + + 12))); + pov += plt_entry_size; + } + + gold_assert(static_cast(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 the PLT section. + +void +Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout) +{ + if (this->plt_ == NULL) + { + // Create the GOT sections first. + this->got_section(symtab, layout); + + this->plt_ = new Output_data_plt_x86_64(layout, this->got_, + this->got_plt_); + layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_EXECINSTR), + this->plt_); + } +} + +// Create a PLT entry for a global symbol. + +void +Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout, + Symbol* gsym) +{ + if (gsym->has_plt_offset()) + return; + + if (this->plt_ == NULL) + this->make_plt_section(symtab, layout); + + this->plt_->add_entry(gsym); +} + +// Define the _TLS_MODULE_BASE_ symbol in the TLS segment. + +void +Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout) +{ + if (this->tls_base_symbol_defined_) + return; + + Output_segment* tls_segment = layout->tls_segment(); + if (tls_segment != NULL) + { + bool is_exec = parameters->options().output_is_executable(); + symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL, + tls_segment, 0, 0, + elfcpp::STT_TLS, + elfcpp::STB_LOCAL, + elfcpp::STV_HIDDEN, 0, + (is_exec + ? Symbol::SEGMENT_END + : Symbol::SEGMENT_START), + true); + } + this->tls_base_symbol_defined_ = true; +} + +// Create the reserved PLT and GOT entries for the TLS descriptor resolver. + +void +Target_x86_64::reserve_tlsdesc_entries(Symbol_table* symtab, + Layout* layout) +{ + if (this->plt_ == NULL) + this->make_plt_section(symtab, layout); + + if (!this->plt_->has_tlsdesc_entry()) + { + // Allocate the TLSDESC_GOT entry. + Output_data_got<64, false>* got = this->got_section(symtab, layout); + unsigned int got_offset = got->add_constant(0); + + // Allocate the TLSDESC_PLT entry. + this->plt_->reserve_tlsdesc_entry(got_offset); + } +} + +// Create a GOT entry for the TLS module index. + +unsigned int +Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout, + Sized_relobj<64, false>* object) +{ + if (this->got_mod_index_offset_ == -1U) + { + gold_assert(symtab != NULL && layout != NULL && object != NULL); + Reloc_section* rela_dyn = this->rela_dyn_section(layout); + Output_data_got<64, false>* got = this->got_section(symtab, layout); + unsigned int got_offset = got->add_constant(0); + rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got, + got_offset, 0); + got->add_constant(0); + this->got_mod_index_offset_ = got_offset; + } + return this->got_mod_index_offset_; +} + +// Optimize the TLS relocation type based on what we know about the +// symbol. IS_FINAL is true if the final address of this symbol is +// known at link time. + +tls::Tls_optimization +Target_x86_64::optimize_tls_reloc(bool is_final, int r_type) +{ + // If we are generating a shared library, then we can't do anything + // in the linker. + if (parameters->options().shared()) + return tls::TLSOPT_NONE; + + switch (r_type) + { + case elfcpp::R_X86_64_TLSGD: + case elfcpp::R_X86_64_GOTPC32_TLSDESC: + case elfcpp::R_X86_64_TLSDESC_CALL: + // These are General-Dynamic which permits fully general TLS + // access. Since we know that we are generating an executable, + // we can convert this to Initial-Exec. If we also know that + // this is a local symbol, we can further switch to Local-Exec. + if (is_final) + return tls::TLSOPT_TO_LE; + return tls::TLSOPT_TO_IE; + + case elfcpp::R_X86_64_TLSLD: + // This is Local-Dynamic, which refers to a local symbol in the + // dynamic TLS block. Since we know that we generating an + // executable, we can switch to Local-Exec. + return tls::TLSOPT_TO_LE; + + case elfcpp::R_X86_64_DTPOFF32: + case elfcpp::R_X86_64_DTPOFF64: + // Another Local-Dynamic reloc. + return tls::TLSOPT_TO_LE; + + case elfcpp::R_X86_64_GOTTPOFF: + // These are Initial-Exec relocs which get the thread offset + // from the GOT. If we know that we are linking against the + // local symbol, we can switch to Local-Exec, which links the + // thread offset into the instruction. + if (is_final) + return tls::TLSOPT_TO_LE; + return tls::TLSOPT_NONE; + + case elfcpp::R_X86_64_TPOFF32: + // When we already have Local-Exec, there is nothing further we + // can do. + return tls::TLSOPT_NONE; + + default: + gold_unreachable(); + } +} + +// Report an unsupported relocation against a local symbol. + +void +Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object, + unsigned int r_type) +{ + gold_error(_("%s: unsupported reloc %u against local symbol"), + object->name().c_str(), r_type); +} + +// We are about to emit a dynamic relocation of type R_TYPE. If the +// dynamic linker does not support it, issue an error. The GNU linker +// only issues a non-PIC error for an allocated read-only section. +// Here we know the section is allocated, but we don't know that it is +// read-only. But we check for all the relocation types which the +// glibc dynamic linker supports, so it seems appropriate to issue an +// error even if the section is not read-only. + +void +Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type) +{ + switch (r_type) + { + // These are the relocation types supported by glibc for x86_64. + case elfcpp::R_X86_64_RELATIVE: + case elfcpp::R_X86_64_GLOB_DAT: + case elfcpp::R_X86_64_JUMP_SLOT: + case elfcpp::R_X86_64_DTPMOD64: + case elfcpp::R_X86_64_DTPOFF64: + case elfcpp::R_X86_64_TPOFF64: + case elfcpp::R_X86_64_64: + case elfcpp::R_X86_64_32: + case elfcpp::R_X86_64_PC32: + case elfcpp::R_X86_64_COPY: + return; + + default: + // This prevents us from issuing more than one error per reloc + // section. But we can still wind up issuing more than one + // error per object file. + if (this->issued_non_pic_error_) + return; + gold_assert(parameters->options().output_is_position_independent()); + object->error(_("requires unsupported dynamic reloc; " + "recompile with -fPIC")); + this->issued_non_pic_error_ = true; + return; + + case elfcpp::R_X86_64_NONE: + gold_unreachable(); + } +} + +// Scan a relocation for a local symbol. + +inline void +Target_x86_64::Scan::local(const General_options&, + Symbol_table* symtab, + Layout* layout, + Target_x86_64* target, + Sized_relobj<64, false>* object, + unsigned int data_shndx, + Output_section* output_section, + const elfcpp::Rela<64, false>& reloc, + unsigned int r_type, + const elfcpp::Sym<64, false>& lsym) +{ + switch (r_type) + { + case elfcpp::R_X86_64_NONE: + case elfcpp::R_386_GNU_VTINHERIT: + case elfcpp::R_386_GNU_VTENTRY: + break; + + case elfcpp::R_X86_64_64: + // If building a shared library (or a position-independent + // executable), we need to create a dynamic relocation for this + // location. The relocation applied at link time will apply the + // link-time value, so we flag the location with an + // R_X86_64_RELATIVE relocation so the dynamic loader can + // relocate it easily. + if (parameters->options().output_is_position_independent()) + { + unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info()); + Reloc_section* rela_dyn = target->rela_dyn_section(layout); + rela_dyn->add_local_relative(object, r_sym, + elfcpp::R_X86_64_RELATIVE, + output_section, data_shndx, + reloc.get_r_offset(), + reloc.get_r_addend()); + } + break; + + case elfcpp::R_X86_64_32: + case elfcpp::R_X86_64_32S: + case elfcpp::R_X86_64_16: + case elfcpp::R_X86_64_8: + // If building a shared library (or a position-independent + // executable), we need to create a dynamic relocation for this + // location. We can't use an R_X86_64_RELATIVE relocation + // because that is always a 64-bit relocation. + if (parameters->options().output_is_position_independent()) + { + this->check_non_pic(object, r_type); + + Reloc_section* rela_dyn = target->rela_dyn_section(layout); + unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info()); + if (lsym.get_st_type() != elfcpp::STT_SECTION) + rela_dyn->add_local(object, r_sym, r_type, output_section, + data_shndx, reloc.get_r_offset(), + reloc.get_r_addend()); + else + { + gold_assert(lsym.get_st_value() == 0); + unsigned int shndx = lsym.get_st_shndx(); + bool is_ordinary; + shndx = object->adjust_sym_shndx(r_sym, shndx, + &is_ordinary); + if (!is_ordinary) + object->error(_("section symbol %u has bad shndx %u"), + r_sym, shndx); + else + rela_dyn->add_local_section(object, shndx, + r_type, output_section, + data_shndx, reloc.get_r_offset(), + reloc.get_r_addend()); + } + } + break; + + case elfcpp::R_X86_64_PC64: + case elfcpp::R_X86_64_PC32: + case elfcpp::R_X86_64_PC16: + case elfcpp::R_X86_64_PC8: + break; + + case elfcpp::R_X86_64_PLT32: + // Since we know this is a local symbol, we can handle this as a + // PC32 reloc. + break; + + case elfcpp::R_X86_64_GOTPC32: + case elfcpp::R_X86_64_GOTOFF64: + case elfcpp::R_X86_64_GOTPC64: + case elfcpp::R_X86_64_PLTOFF64: + // We need a GOT section. + target->got_section(symtab, layout); + // For PLTOFF64, we'd normally want a PLT section, but since we + // know this is a local symbol, no PLT is needed. + break; + + case elfcpp::R_X86_64_GOT64: + case elfcpp::R_X86_64_GOT32: + case elfcpp::R_X86_64_GOTPCREL64: + case elfcpp::R_X86_64_GOTPCREL: + case elfcpp::R_X86_64_GOTPLT64: + { + // The symbol requires a GOT entry. + Output_data_got<64, false>* got = target->got_section(symtab, layout); + unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info()); + if (got->add_local(object, r_sym, GOT_TYPE_STANDARD)) + { + // If we are generating a shared object, we need to add a + // dynamic relocation for this symbol's GOT entry. + if (parameters->options().output_is_position_independent()) + { + Reloc_section* rela_dyn = target->rela_dyn_section(layout); + // R_X86_64_RELATIVE assumes a 64-bit relocation. + if (r_type != elfcpp::R_X86_64_GOT32) + rela_dyn->add_local_relative( + object, r_sym, elfcpp::R_X86_64_RELATIVE, got, + object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0); + else + { + this->check_non_pic(object, r_type); + + gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION); + rela_dyn->add_local( + object, r_sym, r_type, got, + object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0); + } + } + } + // For GOTPLT64, we'd normally want a PLT section, but since + // we know this is a local symbol, no PLT is needed. + } + break; + + case elfcpp::R_X86_64_COPY: + case elfcpp::R_X86_64_GLOB_DAT: + case elfcpp::R_X86_64_JUMP_SLOT: + case elfcpp::R_X86_64_RELATIVE: + // These are outstanding tls relocs, which are unexpected when linking + case elfcpp::R_X86_64_TPOFF64: + case elfcpp::R_X86_64_DTPMOD64: + case elfcpp::R_X86_64_TLSDESC: + gold_error(_("%s: unexpected reloc %u in object file"), + object->name().c_str(), r_type); + break; + + // These are initial tls relocs, which are expected when linking + case elfcpp::R_X86_64_TLSGD: // Global-dynamic + case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) + case elfcpp::R_X86_64_TLSDESC_CALL: + case elfcpp::R_X86_64_TLSLD: // Local-dynamic + case elfcpp::R_X86_64_DTPOFF32: + case elfcpp::R_X86_64_DTPOFF64: + case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec + case elfcpp::R_X86_64_TPOFF32: // Local-exec + { + bool output_is_shared = parameters->options().shared(); + const tls::Tls_optimization optimized_type + = Target_x86_64::optimize_tls_reloc(!output_is_shared, r_type); + switch (r_type) + { + case elfcpp::R_X86_64_TLSGD: // General-dynamic + if (optimized_type == tls::TLSOPT_NONE) + { + // Create a pair of GOT entries for the module index and + // dtv-relative offset. + Output_data_got<64, false>* got + = target->got_section(symtab, layout); + unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info()); + unsigned int shndx = lsym.get_st_shndx(); + bool is_ordinary; + shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); + if (!is_ordinary) + object->error(_("local symbol %u has bad shndx %u"), + r_sym, shndx); + else + got->add_local_pair_with_rela(object, r_sym, + shndx, + GOT_TYPE_TLS_PAIR, + target->rela_dyn_section(layout), + elfcpp::R_X86_64_DTPMOD64, 0); + } + else if (optimized_type != tls::TLSOPT_TO_LE) + unsupported_reloc_local(object, r_type); + break; + + case elfcpp::R_X86_64_GOTPC32_TLSDESC: + target->define_tls_base_symbol(symtab, layout); + if (optimized_type == tls::TLSOPT_NONE) + { + // Create reserved PLT and GOT entries for the resolver. + target->reserve_tlsdesc_entries(symtab, layout); + + // Generate a double GOT entry with an R_X86_64_TLSDESC reloc. + Output_data_got<64, false>* got + = target->got_section(symtab, layout); + unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info()); + unsigned int shndx = lsym.get_st_shndx(); + bool is_ordinary; + shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); + if (!is_ordinary) + object->error(_("local symbol %u has bad shndx %u"), + r_sym, shndx); + else + got->add_local_pair_with_rela(object, r_sym, + shndx, + GOT_TYPE_TLS_DESC, + target->rela_dyn_section(layout), + elfcpp::R_X86_64_TLSDESC, 0); + } + else if (optimized_type != tls::TLSOPT_TO_LE) + unsupported_reloc_local(object, r_type); + break; + + case elfcpp::R_X86_64_TLSDESC_CALL: + break; + + case elfcpp::R_X86_64_TLSLD: // Local-dynamic + if (optimized_type == tls::TLSOPT_NONE) + { + // Create a GOT entry for the module index. + target->got_mod_index_entry(symtab, layout, object); + } + else if (optimized_type != tls::TLSOPT_TO_LE) + unsupported_reloc_local(object, r_type); + break; + + case elfcpp::R_X86_64_DTPOFF32: + case elfcpp::R_X86_64_DTPOFF64: + break; + + case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec + layout->set_has_static_tls(); + if (optimized_type == tls::TLSOPT_NONE) + { + // Create a GOT entry for the tp-relative offset. + Output_data_got<64, false>* got + = target->got_section(symtab, layout); + unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info()); + got->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET, + target->rela_dyn_section(layout), + elfcpp::R_X86_64_TPOFF64); + } + else if (optimized_type != tls::TLSOPT_TO_LE) + unsupported_reloc_local(object, r_type); + break; + + case elfcpp::R_X86_64_TPOFF32: // Local-exec + layout->set_has_static_tls(); + if (output_is_shared) + unsupported_reloc_local(object, r_type); + break; + + default: + gold_unreachable(); + } + } + break; + + case elfcpp::R_X86_64_SIZE32: + case elfcpp::R_X86_64_SIZE64: + default: + gold_error(_("%s: unsupported reloc %u against local symbol"), + object->name().c_str(), r_type); + break; + } +} + + +// Report an unsupported relocation against a global symbol. + +void +Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object, + unsigned int r_type, + Symbol* gsym) +{ + gold_error(_("%s: unsupported reloc %u against global symbol %s"), + object->name().c_str(), r_type, gsym->demangled_name().c_str()); +} + +// Scan a relocation for a global symbol. + +inline void +Target_x86_64::Scan::global(const General_options&, + Symbol_table* symtab, + Layout* layout, + Target_x86_64* target, + Sized_relobj<64, false>* object, + unsigned int data_shndx, + Output_section* output_section, + const elfcpp::Rela<64, false>& reloc, + unsigned int r_type, + Symbol* gsym) +{ + switch (r_type) + { + case elfcpp::R_X86_64_NONE: + case elfcpp::R_386_GNU_VTINHERIT: + case elfcpp::R_386_GNU_VTENTRY: + break; + + case elfcpp::R_X86_64_64: + case elfcpp::R_X86_64_32: + case elfcpp::R_X86_64_32S: + case elfcpp::R_X86_64_16: + case elfcpp::R_X86_64_8: + { + // Make a PLT entry if necessary. + if (gsym->needs_plt_entry()) + { + target->make_plt_entry(symtab, layout, gsym); + // Since this is not a PC-relative relocation, we may be + // taking the address of a function. In that case we need to + // set the entry in the dynamic symbol table to the address of + // the PLT entry. + if (gsym->is_from_dynobj() && !parameters->options().shared()) + gsym->set_needs_dynsym_value(); + } + // Make a dynamic relocation if necessary. + if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF)) + { + if (gsym->may_need_copy_reloc()) + { + target->copy_reloc(symtab, layout, object, + data_shndx, output_section, gsym, reloc); + } + else if (r_type == elfcpp::R_X86_64_64 + && gsym->can_use_relative_reloc(false)) + { + Reloc_section* rela_dyn = target->rela_dyn_section(layout); + rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE, + output_section, object, + data_shndx, reloc.get_r_offset(), + reloc.get_r_addend()); + } + else + { + this->check_non_pic(object, r_type); + Reloc_section* rela_dyn = target->rela_dyn_section(layout); + rela_dyn->add_global(gsym, r_type, output_section, object, + data_shndx, reloc.get_r_offset(), + reloc.get_r_addend()); + } + } + } + break; + + case elfcpp::R_X86_64_PC64: + case elfcpp::R_X86_64_PC32: + case elfcpp::R_X86_64_PC16: + case elfcpp::R_X86_64_PC8: + { + // Make a PLT entry if necessary. + if (gsym->needs_plt_entry()) + target->make_plt_entry(symtab, layout, gsym); + // Make a dynamic relocation if necessary. + int flags = Symbol::NON_PIC_REF; + if (gsym->type() == elfcpp::STT_FUNC) + flags |= Symbol::FUNCTION_CALL; + if (gsym->needs_dynamic_reloc(flags)) + { + if (gsym->may_need_copy_reloc()) + { + target->copy_reloc(symtab, layout, object, + data_shndx, output_section, gsym, reloc); + } + else + { + this->check_non_pic(object, r_type); + Reloc_section* rela_dyn = target->rela_dyn_section(layout); + rela_dyn->add_global(gsym, r_type, output_section, object, + data_shndx, reloc.get_r_offset(), + reloc.get_r_addend()); + } + } + } + break; + + case elfcpp::R_X86_64_GOT64: + case elfcpp::R_X86_64_GOT32: + case elfcpp::R_X86_64_GOTPCREL64: + case elfcpp::R_X86_64_GOTPCREL: + case elfcpp::R_X86_64_GOTPLT64: + { + // The symbol requires a GOT entry. + Output_data_got<64, false>* got = target->got_section(symtab, layout); + if (gsym->final_value_is_known()) + got->add_global(gsym, GOT_TYPE_STANDARD); + else + { + // If this symbol is not fully resolved, we need to add a + // dynamic relocation for it. + Reloc_section* rela_dyn = target->rela_dyn_section(layout); + if (gsym->is_from_dynobj() + || gsym->is_undefined() + || gsym->is_preemptible()) + got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn, + elfcpp::R_X86_64_GLOB_DAT); + else + { + if (got->add_global(gsym, GOT_TYPE_STANDARD)) + rela_dyn->add_global_relative( + gsym, elfcpp::R_X86_64_RELATIVE, got, + gsym->got_offset(GOT_TYPE_STANDARD), 0); + } + } + // For GOTPLT64, we also need a PLT entry (but only if the + // symbol is not fully resolved). + if (r_type == elfcpp::R_X86_64_GOTPLT64 + && !gsym->final_value_is_known()) + target->make_plt_entry(symtab, layout, gsym); + } + break; + + case elfcpp::R_X86_64_PLT32: + // If the symbol is fully resolved, this is just a PC32 reloc. + // Otherwise we need a PLT entry. + if (gsym->final_value_is_known()) + break; + // If building a shared library, we can also skip the PLT entry + // if the symbol is defined in the output file and is protected + // or hidden. + if (gsym->is_defined() + && !gsym->is_from_dynobj() + && !gsym->is_preemptible()) + break; + target->make_plt_entry(symtab, layout, gsym); + break; + + case elfcpp::R_X86_64_GOTPC32: + case elfcpp::R_X86_64_GOTOFF64: + case elfcpp::R_X86_64_GOTPC64: + case elfcpp::R_X86_64_PLTOFF64: + // We need a GOT section. + target->got_section(symtab, layout); + // For PLTOFF64, we also need a PLT entry (but only if the + // symbol is not fully resolved). + if (r_type == elfcpp::R_X86_64_PLTOFF64 + && !gsym->final_value_is_known()) + target->make_plt_entry(symtab, layout, gsym); + break; + + case elfcpp::R_X86_64_COPY: + case elfcpp::R_X86_64_GLOB_DAT: + case elfcpp::R_X86_64_JUMP_SLOT: + case elfcpp::R_X86_64_RELATIVE: + // These are outstanding tls relocs, which are unexpected when linking + case elfcpp::R_X86_64_TPOFF64: + case elfcpp::R_X86_64_DTPMOD64: + case elfcpp::R_X86_64_TLSDESC: + gold_error(_("%s: unexpected reloc %u in object file"), + object->name().c_str(), r_type); + break; + + // These are initial tls relocs, which are expected for global() + case elfcpp::R_X86_64_TLSGD: // Global-dynamic + case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) + case elfcpp::R_X86_64_TLSDESC_CALL: + case elfcpp::R_X86_64_TLSLD: // Local-dynamic + case elfcpp::R_X86_64_DTPOFF32: + case elfcpp::R_X86_64_DTPOFF64: + case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec + case elfcpp::R_X86_64_TPOFF32: // Local-exec + { + const bool is_final = gsym->final_value_is_known(); + const tls::Tls_optimization optimized_type + = Target_x86_64::optimize_tls_reloc(is_final, r_type); + switch (r_type) + { + case elfcpp::R_X86_64_TLSGD: // General-dynamic + if (optimized_type == tls::TLSOPT_NONE) + { + // Create a pair of GOT entries for the module index and + // dtv-relative offset. + Output_data_got<64, false>* got + = target->got_section(symtab, layout); + got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_PAIR, + target->rela_dyn_section(layout), + elfcpp::R_X86_64_DTPMOD64, + elfcpp::R_X86_64_DTPOFF64); + } + else if (optimized_type == tls::TLSOPT_TO_IE) + { + // Create a GOT entry for the tp-relative offset. + Output_data_got<64, false>* got + = target->got_section(symtab, layout); + got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET, + target->rela_dyn_section(layout), + elfcpp::R_X86_64_TPOFF64); + } + else if (optimized_type != tls::TLSOPT_TO_LE) + unsupported_reloc_global(object, r_type, gsym); + break; + + case elfcpp::R_X86_64_GOTPC32_TLSDESC: + target->define_tls_base_symbol(symtab, layout); + if (optimized_type == tls::TLSOPT_NONE) + { + // Create reserved PLT and GOT entries for the resolver. + target->reserve_tlsdesc_entries(symtab, layout); + + // Create a double GOT entry with an R_X86_64_TLSDESC reloc. + Output_data_got<64, false>* got + = target->got_section(symtab, layout); + got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC, + target->rela_dyn_section(layout), + elfcpp::R_X86_64_TLSDESC, 0); + } + else if (optimized_type == tls::TLSOPT_TO_IE) + { + // Create a GOT entry for the tp-relative offset. + Output_data_got<64, false>* got + = target->got_section(symtab, layout); + got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET, + target->rela_dyn_section(layout), + elfcpp::R_X86_64_TPOFF64); + } + else if (optimized_type != tls::TLSOPT_TO_LE) + unsupported_reloc_global(object, r_type, gsym); + break; + + case elfcpp::R_X86_64_TLSDESC_CALL: + break; + + case elfcpp::R_X86_64_TLSLD: // Local-dynamic + if (optimized_type == tls::TLSOPT_NONE) + { + // Create a GOT entry for the module index. + target->got_mod_index_entry(symtab, layout, object); + } + else if (optimized_type != tls::TLSOPT_TO_LE) + unsupported_reloc_global(object, r_type, gsym); + break; + + case elfcpp::R_X86_64_DTPOFF32: + case elfcpp::R_X86_64_DTPOFF64: + break; + + case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec + layout->set_has_static_tls(); + if (optimized_type == tls::TLSOPT_NONE) + { + // Create a GOT entry for the tp-relative offset. + Output_data_got<64, false>* got + = target->got_section(symtab, layout); + got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET, + target->rela_dyn_section(layout), + elfcpp::R_X86_64_TPOFF64); + } + else if (optimized_type != tls::TLSOPT_TO_LE) + unsupported_reloc_global(object, r_type, gsym); + break; + + case elfcpp::R_X86_64_TPOFF32: // Local-exec + layout->set_has_static_tls(); + if (parameters->options().shared()) + unsupported_reloc_local(object, r_type); + break; + + default: + gold_unreachable(); + } + } + break; + + case elfcpp::R_X86_64_SIZE32: + case elfcpp::R_X86_64_SIZE64: + default: + gold_error(_("%s: unsupported reloc %u against global symbol %s"), + object->name().c_str(), r_type, + gsym->demangled_name().c_str()); + break; + } +} + +void +Target_x86_64::gc_process_relocs(const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<64, false>* object, + unsigned int data_shndx, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + bool needs_special_offset_handling, + size_t local_symbol_count, + const unsigned char* plocal_symbols) +{ + + if (sh_type == elfcpp::SHT_REL) + { + return; + } + + gold::gc_process_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA, + Target_x86_64::Scan>( + options, + symtab, + layout, + this, + object, + data_shndx, + prelocs, + reloc_count, + output_section, + needs_special_offset_handling, + local_symbol_count, + plocal_symbols); + +} +// Scan relocations for a section. + +void +Target_x86_64::scan_relocs(const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<64, false>* object, + unsigned int data_shndx, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + bool needs_special_offset_handling, + size_t local_symbol_count, + const unsigned char* plocal_symbols) +{ + if (sh_type == elfcpp::SHT_REL) + { + gold_error(_("%s: unsupported REL reloc section"), + object->name().c_str()); + return; + } + + gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA, + Target_x86_64::Scan>( + 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_x86_64::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_RELA); + if (this->plt_->has_tlsdesc_entry()) + { + unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset(); + unsigned int got_offset = this->plt_->get_tlsdesc_got_offset(); + this->got_->finalize_data_size(); + odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT, + this->plt_, plt_offset); + odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT, + this->got_, got_offset); + } + } + + if (this->rela_dyn_ != NULL) + { + const Output_data* od = this->rela_dyn_; + odyn->add_section_address(elfcpp::DT_RELA, od); + odyn->add_section_size(elfcpp::DT_RELASZ, od); + odyn->add_constant(elfcpp::DT_RELAENT, + elfcpp::Elf_sizes<64>::rela_size); + } + + if (!parameters->options().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_.any_saved_relocs()) + this->copy_relocs_.emit(this->rela_dyn_section(layout)); +} + +// Perform a relocation. + +inline bool +Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo, + Target_x86_64* target, + Output_section*, + size_t relnum, + const elfcpp::Rela<64, false>& rela, + unsigned int r_type, + const Sized_symbol<64>* gsym, + const Symbol_value<64>* psymval, + unsigned char* view, + elfcpp::Elf_types<64>::Elf_Addr address, + section_size_type view_size) +{ + if (this->skip_call_tls_get_addr_) + { + if ((r_type != elfcpp::R_X86_64_PLT32 + && r_type != elfcpp::R_X86_64_PC32) + || gsym == NULL + || strcmp(gsym->name(), "__tls_get_addr") != 0) + { + gold_error_at_location(relinfo, relnum, rela.get_r_offset(), + _("missing expected TLS relocation")); + } + else + { + this->skip_call_tls_get_addr_ = false; + return false; + } + } + + // Pick the value to use for symbols defined in shared objects. + Symbol_value<64> symval; + if (gsym != NULL + && gsym->use_plt_offset(r_type == elfcpp::R_X86_64_PC64 + || r_type == elfcpp::R_X86_64_PC32 + || r_type == elfcpp::R_X86_64_PC16 + || r_type == elfcpp::R_X86_64_PC8)) + { + symval.set_output_value(target->plt_section()->address() + + gsym->plt_offset()); + psymval = &symval; + } + + const Sized_relobj<64, false>* object = relinfo->object; + const elfcpp::Elf_Xword addend = rela.get_r_addend(); + + // Get the GOT offset if needed. + // The GOT pointer points to the end of the GOT section. + // We need to subtract the size of the GOT section to get + // the actual offset to use in the relocation. + bool have_got_offset = false; + unsigned int got_offset = 0; + switch (r_type) + { + case elfcpp::R_X86_64_GOT32: + case elfcpp::R_X86_64_GOT64: + case elfcpp::R_X86_64_GOTPLT64: + case elfcpp::R_X86_64_GOTPCREL: + case elfcpp::R_X86_64_GOTPCREL64: + if (gsym != NULL) + { + gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD)); + got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size(); + } + else + { + unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info()); + gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD)); + got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD) + - target->got_size()); + } + have_got_offset = true; + break; + + default: + break; + } + + switch (r_type) + { + case elfcpp::R_X86_64_NONE: + case elfcpp::R_386_GNU_VTINHERIT: + case elfcpp::R_386_GNU_VTENTRY: + break; + + case elfcpp::R_X86_64_64: + Relocate_functions<64, false>::rela64(view, object, psymval, addend); + break; + + case elfcpp::R_X86_64_PC64: + Relocate_functions<64, false>::pcrela64(view, object, psymval, addend, + address); + break; + + case elfcpp::R_X86_64_32: + // FIXME: we need to verify that value + addend fits into 32 bits: + // uint64_t x = value + addend; + // x == static_cast(static_cast(x)) + // Likewise for other <=32-bit relocations (but see R_X86_64_32S). + Relocate_functions<64, false>::rela32(view, object, psymval, addend); + break; + + case elfcpp::R_X86_64_32S: + // FIXME: we need to verify that value + addend fits into 32 bits: + // int64_t x = value + addend; // note this quantity is signed! + // x == static_cast(static_cast(x)) + Relocate_functions<64, false>::rela32(view, object, psymval, addend); + break; + + case elfcpp::R_X86_64_PC32: + Relocate_functions<64, false>::pcrela32(view, object, psymval, addend, + address); + break; + + case elfcpp::R_X86_64_16: + Relocate_functions<64, false>::rela16(view, object, psymval, addend); + break; + + case elfcpp::R_X86_64_PC16: + Relocate_functions<64, false>::pcrela16(view, object, psymval, addend, + address); + break; + + case elfcpp::R_X86_64_8: + Relocate_functions<64, false>::rela8(view, object, psymval, addend); + break; + + case elfcpp::R_X86_64_PC8: + Relocate_functions<64, false>::pcrela8(view, object, psymval, addend, + address); + break; + + case elfcpp::R_X86_64_PLT32: + gold_assert(gsym == NULL + || gsym->has_plt_offset() + || gsym->final_value_is_known() + || (gsym->is_defined() + && !gsym->is_from_dynobj() + && !gsym->is_preemptible())); + // Note: while this code looks the same as for R_X86_64_PC32, it + // behaves differently because psymval was set to point to + // the PLT entry, rather than the symbol, in Scan::global(). + Relocate_functions<64, false>::pcrela32(view, object, psymval, addend, + address); + break; + + case elfcpp::R_X86_64_PLTOFF64: + { + gold_assert(gsym); + gold_assert(gsym->has_plt_offset() + || gsym->final_value_is_known()); + elfcpp::Elf_types<64>::Elf_Addr got_address; + got_address = target->got_section(NULL, NULL)->address(); + Relocate_functions<64, false>::rela64(view, object, psymval, + addend - got_address); + } + + case elfcpp::R_X86_64_GOT32: + gold_assert(have_got_offset); + Relocate_functions<64, false>::rela32(view, got_offset, addend); + break; + + case elfcpp::R_X86_64_GOTPC32: + { + gold_assert(gsym); + elfcpp::Elf_types<64>::Elf_Addr value; + value = target->got_plt_section()->address(); + Relocate_functions<64, false>::pcrela32(view, value, addend, address); + } + break; + + case elfcpp::R_X86_64_GOT64: + // The ABI doc says "Like GOT64, but indicates a PLT entry is needed." + // Since we always add a PLT entry, this is equivalent. + case elfcpp::R_X86_64_GOTPLT64: + gold_assert(have_got_offset); + Relocate_functions<64, false>::rela64(view, got_offset, addend); + break; + + case elfcpp::R_X86_64_GOTPC64: + { + gold_assert(gsym); + elfcpp::Elf_types<64>::Elf_Addr value; + value = target->got_plt_section()->address(); + Relocate_functions<64, false>::pcrela64(view, value, addend, address); + } + break; + + case elfcpp::R_X86_64_GOTOFF64: + { + elfcpp::Elf_types<64>::Elf_Addr value; + value = (psymval->value(object, 0) + - target->got_plt_section()->address()); + Relocate_functions<64, false>::rela64(view, value, addend); + } + break; + + case elfcpp::R_X86_64_GOTPCREL: + { + gold_assert(have_got_offset); + elfcpp::Elf_types<64>::Elf_Addr value; + value = target->got_plt_section()->address() + got_offset; + Relocate_functions<64, false>::pcrela32(view, value, addend, address); + } + break; + + case elfcpp::R_X86_64_GOTPCREL64: + { + gold_assert(have_got_offset); + elfcpp::Elf_types<64>::Elf_Addr value; + value = target->got_plt_section()->address() + got_offset; + Relocate_functions<64, false>::pcrela64(view, value, addend, address); + } + break; + + case elfcpp::R_X86_64_COPY: + case elfcpp::R_X86_64_GLOB_DAT: + case elfcpp::R_X86_64_JUMP_SLOT: + case elfcpp::R_X86_64_RELATIVE: + // These are outstanding tls relocs, which are unexpected when linking + case elfcpp::R_X86_64_TPOFF64: + case elfcpp::R_X86_64_DTPMOD64: + case elfcpp::R_X86_64_TLSDESC: + gold_error_at_location(relinfo, relnum, rela.get_r_offset(), + _("unexpected reloc %u in object file"), + r_type); + break; + + // These are initial tls relocs, which are expected when linking + case elfcpp::R_X86_64_TLSGD: // Global-dynamic + case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) + case elfcpp::R_X86_64_TLSDESC_CALL: + case elfcpp::R_X86_64_TLSLD: // Local-dynamic + case elfcpp::R_X86_64_DTPOFF32: + case elfcpp::R_X86_64_DTPOFF64: + case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec + case elfcpp::R_X86_64_TPOFF32: // Local-exec + this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval, + view, address, view_size); + break; + + case elfcpp::R_X86_64_SIZE32: + case elfcpp::R_X86_64_SIZE64: + default: + gold_error_at_location(relinfo, relnum, rela.get_r_offset(), + _("unsupported reloc %u"), + r_type); + break; + } + + return true; +} + +// Perform a TLS relocation. + +inline void +Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, + Target_x86_64* target, + size_t relnum, + const elfcpp::Rela<64, false>& rela, + unsigned int r_type, + const Sized_symbol<64>* gsym, + const Symbol_value<64>* psymval, + unsigned char* view, + elfcpp::Elf_types<64>::Elf_Addr address, + section_size_type view_size) +{ + Output_segment* tls_segment = relinfo->layout->tls_segment(); + + const Sized_relobj<64, false>* object = relinfo->object; + const elfcpp::Elf_Xword addend = rela.get_r_addend(); + + elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0); + + const bool is_final = (gsym == NULL + ? !parameters->options().output_is_position_independent() + : gsym->final_value_is_known()); + const tls::Tls_optimization optimized_type + = Target_x86_64::optimize_tls_reloc(is_final, r_type); + switch (r_type) + { + case elfcpp::R_X86_64_TLSGD: // Global-dynamic + this->saw_tls_block_reloc_ = true; + if (optimized_type == tls::TLSOPT_TO_LE) + { + gold_assert(tls_segment != NULL); + this->tls_gd_to_le(relinfo, relnum, tls_segment, + rela, r_type, value, view, + view_size); + break; + } + else + { + unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE + ? GOT_TYPE_TLS_OFFSET + : GOT_TYPE_TLS_PAIR); + unsigned int got_offset; + if (gsym != NULL) + { + gold_assert(gsym->has_got_offset(got_type)); + got_offset = gsym->got_offset(got_type) - target->got_size(); + } + else + { + unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info()); + gold_assert(object->local_has_got_offset(r_sym, got_type)); + got_offset = (object->local_got_offset(r_sym, got_type) + - target->got_size()); + } + if (optimized_type == tls::TLSOPT_TO_IE) + { + gold_assert(tls_segment != NULL); + value = target->got_plt_section()->address() + got_offset; + this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type, + value, view, address, view_size); + break; + } + else if (optimized_type == tls::TLSOPT_NONE) + { + // Relocate the field with the offset of the pair of GOT + // entries. + value = target->got_plt_section()->address() + got_offset; + Relocate_functions<64, false>::pcrela32(view, value, addend, + address); + break; + } + } + gold_error_at_location(relinfo, relnum, rela.get_r_offset(), + _("unsupported reloc %u"), r_type); + break; + + case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) + case elfcpp::R_X86_64_TLSDESC_CALL: + this->saw_tls_block_reloc_ = true; + if (optimized_type == tls::TLSOPT_TO_LE) + { + gold_assert(tls_segment != NULL); + this->tls_desc_gd_to_le(relinfo, relnum, tls_segment, + rela, r_type, value, view, + view_size); + break; + } + else + { + unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE + ? GOT_TYPE_TLS_OFFSET + : GOT_TYPE_TLS_DESC); + unsigned int got_offset; + if (gsym != NULL) + { + gold_assert(gsym->has_got_offset(got_type)); + got_offset = gsym->got_offset(got_type) - target->got_size(); + } + else + { + unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info()); + gold_assert(object->local_has_got_offset(r_sym, got_type)); + got_offset = (object->local_got_offset(r_sym, got_type) + - target->got_size()); + } + if (optimized_type == tls::TLSOPT_TO_IE) + { + gold_assert(tls_segment != NULL); + value = target->got_plt_section()->address() + got_offset; + this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, + rela, r_type, value, view, address, + view_size); + break; + } + else if (optimized_type == tls::TLSOPT_NONE) + { + if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC) + { + // Relocate the field with the offset of the pair of GOT + // entries. + value = target->got_plt_section()->address() + got_offset; + Relocate_functions<64, false>::pcrela32(view, value, addend, + address); + } + break; + } + } + gold_error_at_location(relinfo, relnum, rela.get_r_offset(), + _("unsupported reloc %u"), r_type); + break; + + case elfcpp::R_X86_64_TLSLD: // Local-dynamic + this->saw_tls_block_reloc_ = true; + if (optimized_type == tls::TLSOPT_TO_LE) + { + gold_assert(tls_segment != NULL); + this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type, + value, view, view_size); + break; + } + else if (optimized_type == tls::TLSOPT_NONE) + { + // Relocate the field with the offset of the GOT entry for + // the module index. + unsigned int got_offset; + got_offset = (target->got_mod_index_entry(NULL, NULL, NULL) + - target->got_size()); + value = target->got_plt_section()->address() + got_offset; + Relocate_functions<64, false>::pcrela32(view, value, addend, + address); + break; + } + gold_error_at_location(relinfo, relnum, rela.get_r_offset(), + _("unsupported reloc %u"), r_type); + break; + + case elfcpp::R_X86_64_DTPOFF32: + if (optimized_type == tls::TLSOPT_TO_LE) + { + // This relocation type is used in debugging information. + // In that case we need to not optimize the value. If we + // haven't seen a TLSLD reloc, then we assume we should not + // optimize this reloc. + if (this->saw_tls_block_reloc_) + { + gold_assert(tls_segment != NULL); + value -= tls_segment->memsz(); + } + } + Relocate_functions<64, false>::rela32(view, value, addend); + break; + + case elfcpp::R_X86_64_DTPOFF64: + if (optimized_type == tls::TLSOPT_TO_LE) + { + // See R_X86_64_DTPOFF32, just above, for why we test this. + if (this->saw_tls_block_reloc_) + { + gold_assert(tls_segment != NULL); + value -= tls_segment->memsz(); + } + } + Relocate_functions<64, false>::rela64(view, value, addend); + break; + + case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec + if (optimized_type == tls::TLSOPT_TO_LE) + { + gold_assert(tls_segment != NULL); + Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment, + rela, r_type, value, view, + view_size); + break; + } + else if (optimized_type == tls::TLSOPT_NONE) + { + // Relocate the field with the offset of the GOT entry for + // the tp-relative offset of the symbol. + unsigned int got_offset; + if (gsym != NULL) + { + gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET)); + got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET) + - target->got_size()); + } + else + { + unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info()); + gold_assert(object->local_has_got_offset(r_sym, + GOT_TYPE_TLS_OFFSET)); + got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET) + - target->got_size()); + } + value = target->got_plt_section()->address() + got_offset; + Relocate_functions<64, false>::pcrela32(view, value, addend, address); + break; + } + gold_error_at_location(relinfo, relnum, rela.get_r_offset(), + _("unsupported reloc type %u"), + r_type); + break; + + case elfcpp::R_X86_64_TPOFF32: // Local-exec + value -= tls_segment->memsz(); + Relocate_functions<64, false>::rela32(view, value, addend); + break; + } +} + +// Do a relocation in which we convert a TLS General-Dynamic to an +// Initial-Exec. + +inline void +Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo, + size_t relnum, + Output_segment*, + const elfcpp::Rela<64, false>& rela, + unsigned int, + elfcpp::Elf_types<64>::Elf_Addr value, + unsigned char* view, + elfcpp::Elf_types<64>::Elf_Addr address, + section_size_type view_size) +{ + // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; + // .word 0x6666; rex64; call __tls_get_addr + // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax + + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4); + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12); + + tls::check_tls(relinfo, relnum, rela.get_r_offset(), + (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0)); + tls::check_tls(relinfo, relnum, rela.get_r_offset(), + (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0)); + + memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16); + + const elfcpp::Elf_Xword addend = rela.get_r_addend(); + Relocate_functions<64, false>::pcrela32(view + 8, value, addend - 8, address); + + // The next reloc should be a PLT32 reloc against __tls_get_addr. + // We can skip it. + this->skip_call_tls_get_addr_ = true; +} + +// Do a relocation in which we convert a TLS General-Dynamic to a +// Local-Exec. + +inline void +Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo, + size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rela<64, false>& rela, + unsigned int, + elfcpp::Elf_types<64>::Elf_Addr value, + unsigned char* view, + section_size_type view_size) +{ + // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; + // .word 0x6666; rex64; call __tls_get_addr + // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax + + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -4); + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12); + + tls::check_tls(relinfo, relnum, rela.get_r_offset(), + (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0)); + tls::check_tls(relinfo, relnum, rela.get_r_offset(), + (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0)); + + memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 16); + + value -= tls_segment->memsz(); + Relocate_functions<64, false>::rela32(view + 8, value, 0); + + // The next reloc should be a PLT32 reloc against __tls_get_addr. + // We can skip it. + this->skip_call_tls_get_addr_ = true; +} + +// Do a TLSDESC-style General-Dynamic to Initial-Exec transition. + +inline void +Target_x86_64::Relocate::tls_desc_gd_to_ie( + const Relocate_info<64, false>* relinfo, + size_t relnum, + Output_segment*, + const elfcpp::Rela<64, false>& rela, + unsigned int r_type, + elfcpp::Elf_types<64>::Elf_Addr value, + unsigned char* view, + elfcpp::Elf_types<64>::Elf_Addr address, + section_size_type view_size) +{ + if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC) + { + // leaq foo@tlsdesc(%rip), %rax + // ==> movq foo@gottpoff(%rip), %rax + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4); + tls::check_tls(relinfo, relnum, rela.get_r_offset(), + view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05); + view[-2] = 0x8b; + const elfcpp::Elf_Xword addend = rela.get_r_addend(); + Relocate_functions<64, false>::pcrela32(view, value, addend, address); + } + else + { + // call *foo@tlscall(%rax) + // ==> nop; nop + gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL); + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2); + tls::check_tls(relinfo, relnum, rela.get_r_offset(), + view[0] == 0xff && view[1] == 0x10); + view[0] = 0x66; + view[1] = 0x90; + } +} + +// Do a TLSDESC-style General-Dynamic to Local-Exec transition. + +inline void +Target_x86_64::Relocate::tls_desc_gd_to_le( + const Relocate_info<64, false>* relinfo, + size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rela<64, false>& rela, + unsigned int r_type, + elfcpp::Elf_types<64>::Elf_Addr value, + unsigned char* view, + section_size_type view_size) +{ + if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC) + { + // leaq foo@tlsdesc(%rip), %rax + // ==> movq foo@tpoff, %rax + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4); + tls::check_tls(relinfo, relnum, rela.get_r_offset(), + view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x05); + view[-2] = 0xc7; + view[-1] = 0xc0; + value -= tls_segment->memsz(); + Relocate_functions<64, false>::rela32(view, value, 0); + } + else + { + // call *foo@tlscall(%rax) + // ==> nop; nop + gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL); + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2); + tls::check_tls(relinfo, relnum, rela.get_r_offset(), + view[0] == 0xff && view[1] == 0x10); + view[0] = 0x66; + view[1] = 0x90; + } +} + +inline void +Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo, + size_t relnum, + Output_segment*, + const elfcpp::Rela<64, false>& rela, + unsigned int, + elfcpp::Elf_types<64>::Elf_Addr, + unsigned char* view, + section_size_type view_size) +{ + // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt; + // ... leq foo@dtpoff(%rax),%reg + // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx + + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9); + + tls::check_tls(relinfo, relnum, rela.get_r_offset(), + view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d); + + tls::check_tls(relinfo, relnum, rela.get_r_offset(), view[4] == 0xe8); + + memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12); + + // The next reloc should be a PLT32 reloc against __tls_get_addr. + // We can skip it. + this->skip_call_tls_get_addr_ = true; +} + +// Do a relocation in which we convert a TLS Initial-Exec to a +// Local-Exec. + +inline void +Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo, + size_t relnum, + Output_segment* tls_segment, + const elfcpp::Rela<64, false>& rela, + unsigned int, + elfcpp::Elf_types<64>::Elf_Addr value, + unsigned char* view, + section_size_type view_size) +{ + // We need to examine the opcodes to figure out which instruction we + // are looking at. + + // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg + // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg + + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); + tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4); + + unsigned char op1 = view[-3]; + unsigned char op2 = view[-2]; + unsigned char op3 = view[-1]; + unsigned char reg = op3 >> 3; + + if (op2 == 0x8b) + { + // movq + if (op1 == 0x4c) + view[-3] = 0x49; + view[-2] = 0xc7; + view[-1] = 0xc0 | reg; + } + else if (reg == 4) + { + // Special handling for %rsp. + if (op1 == 0x4c) + view[-3] = 0x49; + view[-2] = 0x81; + view[-1] = 0xc0 | reg; + } + else + { + // addq + if (op1 == 0x4c) + view[-3] = 0x4d; + view[-2] = 0x8d; + view[-1] = 0x80 | reg | (reg << 3); + } + + value -= tls_segment->memsz(); + Relocate_functions<64, false>::rela32(view, value, 0); +} + +// Relocate section data. + +void +Target_x86_64::relocate_section( + const Relocate_info<64, false>* relinfo, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + bool needs_special_offset_handling, + unsigned char* view, + elfcpp::Elf_types<64>::Elf_Addr address, + section_size_type view_size, + const Reloc_symbol_changes* reloc_symbol_changes) +{ + gold_assert(sh_type == elfcpp::SHT_RELA); + + gold::relocate_section<64, false, Target_x86_64, elfcpp::SHT_RELA, + Target_x86_64::Relocate>( + relinfo, + this, + prelocs, + reloc_count, + output_section, + needs_special_offset_handling, + view, + address, + view_size, + reloc_symbol_changes); +} + +// Return the size of a relocation while scanning during a relocatable +// link. + +unsigned int +Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc( + unsigned int r_type, + Relobj* object) +{ + switch (r_type) + { + case elfcpp::R_X86_64_NONE: + case elfcpp::R_386_GNU_VTINHERIT: + case elfcpp::R_386_GNU_VTENTRY: + case elfcpp::R_X86_64_TLSGD: // Global-dynamic + case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) + case elfcpp::R_X86_64_TLSDESC_CALL: + case elfcpp::R_X86_64_TLSLD: // Local-dynamic + case elfcpp::R_X86_64_DTPOFF32: + case elfcpp::R_X86_64_DTPOFF64: + case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec + case elfcpp::R_X86_64_TPOFF32: // Local-exec + return 0; + + case elfcpp::R_X86_64_64: + case elfcpp::R_X86_64_PC64: + case elfcpp::R_X86_64_GOTOFF64: + case elfcpp::R_X86_64_GOTPC64: + case elfcpp::R_X86_64_PLTOFF64: + case elfcpp::R_X86_64_GOT64: + case elfcpp::R_X86_64_GOTPCREL64: + case elfcpp::R_X86_64_GOTPCREL: + case elfcpp::R_X86_64_GOTPLT64: + return 8; + + case elfcpp::R_X86_64_32: + case elfcpp::R_X86_64_32S: + case elfcpp::R_X86_64_PC32: + case elfcpp::R_X86_64_PLT32: + case elfcpp::R_X86_64_GOTPC32: + case elfcpp::R_X86_64_GOT32: + return 4; + + case elfcpp::R_X86_64_16: + case elfcpp::R_X86_64_PC16: + return 2; + + case elfcpp::R_X86_64_8: + case elfcpp::R_X86_64_PC8: + return 1; + + case elfcpp::R_X86_64_COPY: + case elfcpp::R_X86_64_GLOB_DAT: + case elfcpp::R_X86_64_JUMP_SLOT: + case elfcpp::R_X86_64_RELATIVE: + // These are outstanding tls relocs, which are unexpected when linking + case elfcpp::R_X86_64_TPOFF64: + case elfcpp::R_X86_64_DTPMOD64: + case elfcpp::R_X86_64_TLSDESC: + object->error(_("unexpected reloc %u in object file"), r_type); + return 0; + + case elfcpp::R_X86_64_SIZE32: + case elfcpp::R_X86_64_SIZE64: + default: + object->error(_("unsupported reloc %u against local symbol"), r_type); + return 0; + } +} + +// Scan the relocs during a relocatable link. + +void +Target_x86_64::scan_relocatable_relocs(const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<64, false>* object, + unsigned int data_shndx, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + bool needs_special_offset_handling, + size_t local_symbol_count, + const unsigned char* plocal_symbols, + Relocatable_relocs* rr) +{ + gold_assert(sh_type == elfcpp::SHT_RELA); + + typedef gold::Default_scan_relocatable_relocs Scan_relocatable_relocs; + + gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA, + Scan_relocatable_relocs>( + options, + symtab, + layout, + object, + data_shndx, + prelocs, + reloc_count, + output_section, + needs_special_offset_handling, + local_symbol_count, + plocal_symbols, + rr); +} + +// Relocate a section during a relocatable link. + +void +Target_x86_64::relocate_for_relocatable( + const Relocate_info<64, false>* relinfo, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + off_t offset_in_output_section, + const Relocatable_relocs* rr, + unsigned char* view, + elfcpp::Elf_types<64>::Elf_Addr view_address, + section_size_type view_size, + unsigned char* reloc_view, + section_size_type reloc_view_size) +{ + gold_assert(sh_type == elfcpp::SHT_RELA); + + gold::relocate_for_relocatable<64, false, elfcpp::SHT_RELA>( + relinfo, + prelocs, + reloc_count, + output_section, + offset_in_output_section, + rr, + view, + view_address, + view_size, + reloc_view, + reloc_view_size); +} + +// Return the value to use for a dynamic which requires special +// treatment. This is how we support equality comparisons of function +// pointers across shared library boundaries, as described in the +// processor specific ABI supplement. + +uint64_t +Target_x86_64::do_dynsym_value(const Symbol* gsym) const +{ + gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset()); + return this->plt_section()->address() + gsym->plt_offset(); +} + +// Return a string used to fill a code section with nops to take up +// the specified length. + +std::string +Target_x86_64::do_code_fill(section_size_type length) const +{ + if (length >= 16) + { + // Build a jmpq instruction to skip over the bytes. + unsigned char jmp[5]; + jmp[0] = 0xe9; + elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5); + return (std::string(reinterpret_cast(&jmp[0]), 5) + + std::string(length - 5, '\0')); + } + + // Nop sequences of various lengths. + const char nop1[1] = { 0x90 }; // nop + const char nop2[2] = { 0x66, 0x90 }; // xchg %ax %ax + const char nop3[3] = { 0x0f, 0x1f, 0x00 }; // nop (%rax) + const char nop4[4] = { 0x0f, 0x1f, 0x40, 0x00}; // nop 0(%rax) + const char nop5[5] = { 0x0f, 0x1f, 0x44, 0x00, // nop 0(%rax,%rax,1) + 0x00 }; + const char nop6[6] = { 0x66, 0x0f, 0x1f, 0x44, // nopw 0(%rax,%rax,1) + 0x00, 0x00 }; + const char nop7[7] = { 0x0f, 0x1f, 0x80, 0x00, // nopl 0L(%rax) + 0x00, 0x00, 0x00 }; + const char nop8[8] = { 0x0f, 0x1f, 0x84, 0x00, // nopl 0L(%rax,%rax,1) + 0x00, 0x00, 0x00, 0x00 }; + const char nop9[9] = { 0x66, 0x0f, 0x1f, 0x84, // nopw 0L(%rax,%rax,1) + 0x00, 0x00, 0x00, 0x00, + 0x00 }; + const char nop10[10] = { 0x66, 0x2e, 0x0f, 0x1f, // nopw %cs:0L(%rax,%rax,1) + 0x84, 0x00, 0x00, 0x00, + 0x00, 0x00 }; + const char nop11[11] = { 0x66, 0x66, 0x2e, 0x0f, // data16 + 0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1) + 0x00, 0x00, 0x00 }; + const char nop12[12] = { 0x66, 0x66, 0x66, 0x2e, // data16; data16 + 0x0f, 0x1f, 0x84, 0x00, // nopw %cs:0L(%rax,%rax,1) + 0x00, 0x00, 0x00, 0x00 }; + const char nop13[13] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16 + 0x2e, 0x0f, 0x1f, 0x84, // nopw %cs:0L(%rax,%rax,1) + 0x00, 0x00, 0x00, 0x00, + 0x00 }; + const char nop14[14] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16 + 0x66, 0x2e, 0x0f, 0x1f, // data16 + 0x84, 0x00, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1) + 0x00, 0x00 }; + const char nop15[15] = { 0x66, 0x66, 0x66, 0x66, // data16; data16; data16 + 0x66, 0x66, 0x2e, 0x0f, // data16; data16 + 0x1f, 0x84, 0x00, 0x00, // nopw %cs:0L(%rax,%rax,1) + 0x00, 0x00, 0x00 }; + + const char* nops[16] = { + NULL, + nop1, nop2, nop3, nop4, nop5, nop6, nop7, + nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15 + }; + + return std::string(nops[length], length); +} + +// FNOFFSET in section SHNDX in OBJECT is the start of a function +// compiled with -fstack-split. The function calls non-stack-split +// code. We have to change the function so that it always ensures +// that it has enough stack space to run some random function. + +void +Target_x86_64::do_calls_non_split(Relobj* object, unsigned int shndx, + section_offset_type fnoffset, + section_size_type fnsize, + unsigned char* view, + section_size_type view_size, + std::string* from, + std::string* to) const +{ + // The function starts with a comparison of the stack pointer and a + // field in the TCB. This is followed by a jump. + + // cmp %fs:NN,%rsp + if (this->match_view(view, view_size, fnoffset, "\x64\x48\x3b\x24\x25", 5) + && fnsize > 9) + { + // We will call __morestack if the carry flag is set after this + // comparison. We turn the comparison into an stc instruction + // and some nops. + view[fnoffset] = '\xf9'; + this->set_view_to_nop(view, view_size, fnoffset + 1, 8); + } + // lea NN(%rsp),%r10 + else if (this->match_view(view, view_size, fnoffset, "\x4c\x8d\x94\x24", 4) + && fnsize > 8) + { + // This is loading an offset from the stack pointer for a + // comparison. The offset is negative, so we decrease the + // offset by the amount of space we need for the stack. This + // means we will avoid calling __morestack if there happens to + // be plenty of space on the stack already. + unsigned char* pval = view + fnoffset + 4; + uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval); + val -= parameters->options().split_stack_adjust_size(); + elfcpp::Swap_unaligned<32, false>::writeval(pval, val); + } + else + { + if (!object->has_no_split_stack()) + object->error(_("failed to match split-stack sequence at " + "section %u offset %0zx"), + shndx, fnoffset); + return; + } + + // We have to change the function so that it calls + // __morestack_non_split instead of __morestack. The former will + // allocate additional stack space. + *from = "__morestack"; + *to = "__morestack_non_split"; +} + +// The selector for x86_64 object files. + +class Target_selector_x86_64 : public Target_selector_freebsd +{ +public: + Target_selector_x86_64() + : Target_selector_freebsd(elfcpp::EM_X86_64, 64, false, "elf64-x86-64", + "elf64-x86-64-freebsd") + { } + + Target* + do_instantiate_target() + { return new Target_x86_64(); } + +}; + +Target_selector_x86_64 target_selector_x86_64; + +} // End anonymous namespace.