X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gold%2Fx86_64.cc;h=9110278ebb8414ef2dcccc822734202aad21a320;hb=ce97fa81e0c46d216b80b143ad8c02fff6906fef;hp=6df501d7b9b0fc5074cf05316cc0794711d62183;hpb=535890bb6466aa82b46ea191a37e75b8936aa913;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/x86_64.cc b/gold/x86_64.cc index 6df501d7b9..9110278ebb 100644 --- a/gold/x86_64.cc +++ b/gold/x86_64.cc @@ -1,33 +1,24 @@ // x86_64.cc -- x86_64 target support for gold. -// Copyright 2006, 2007, Free Software Foundation, Inc. +// 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 Library General Public License -// as published by the Free Software Foundation; either version 2, or +// 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. -// In addition to the permissions in the GNU Library General Public -// License, the Free Software Foundation gives you unlimited -// permission to link the compiled version of this file into -// combinations with other programs, and to distribute those -// combinations without any restriction coming from the use of this -// file. (The Library Public License restrictions do apply in other -// respects; for example, they cover modification of the file, and -/// distribution when not linked into a combined executable.) - -// 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 -// Library General Public License for more details. - -// You should have received a copy of the GNU Library 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. +// 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" @@ -41,10 +32,14 @@ #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" +#include "icf.h" namespace { @@ -60,7 +55,7 @@ class Output_data_plt_x86_64; // 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 Sized_target<64, false> +class Target_x86_64 : public Target_freebsd<64, false> { public: // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures @@ -68,15 +63,44 @@ class Target_x86_64 : public Sized_target<64, false> typedef Output_data_reloc Reloc_section; Target_x86_64() - : Sized_target<64, false>(&x86_64_info), - got_(NULL), plt_(NULL), got_plt_(NULL), rela_dyn_(NULL), - copy_relocs_(NULL), dynbss_(NULL), got_mod_index_offset_(-1U) + : Target_freebsd<64, false>(&x86_64_info), + got_(NULL), plt_(NULL), got_plt_(NULL), global_offset_table_(NULL), + rela_dyn_(NULL), copy_relocs_(elfcpp::R_X86_64_COPY), dynbss_(NULL), + got_mod_index_offset_(-1U), tlsdesc_reloc_info_(), + tls_base_symbol_defined_(false) { } + // This function should be defined in targets that can use relocation + // types to determine (implemented in local_reloc_may_be_function_pointer + // and global_reloc_may_be_function_pointer) + // if a function's pointer is taken. ICF uses this in safe mode to only + // fold those functions whose pointer is defintely not taken. For x86_64 + // pie binaries, safe ICF cannot be done by looking at relocation types. + inline bool + can_check_for_function_pointers() const + { return !parameters->options().pie(); } + + // 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(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, + scan_relocs(Symbol_table* symtab, Layout* layout, Sized_relobj<64, false>* object, unsigned int data_shndx, @@ -90,7 +114,7 @@ class Target_x86_64 : public Sized_target<64, false> // Finalize the sections. void - do_finalize_sections(Layout*); + do_finalize_sections(Layout*, const Input_objects*, Symbol_table*); // Return the value to use for a dynamic which requires special // treatment. @@ -107,32 +131,96 @@ class Target_x86_64 : public Sized_target<64, false> bool needs_special_offset_handling, unsigned char* view, elfcpp::Elf_types<64>::Elf_Addr view_address, - off_t view_size); + section_size_type view_size, + const Reloc_symbol_changes*); + + // Scan the relocs during a relocatable link. + void + scan_relocatable_relocs(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(off_t length); + do_code_fill(section_size_type length) const; // Return whether SYM is defined by the ABI. bool - do_is_defined_by_abi(Symbol* sym) const + do_is_defined_by_abi(const Symbol* sym) const { return strcmp(sym->name(), "__tls_get_addr") == 0; } + // Return the symbol index to use for a target specific relocation. + // The only target specific relocation is R_X86_64_TLSDESC for a + // local symbol, which is an absolute reloc. + unsigned int + do_reloc_symbol_index(void*, unsigned int r_type) const + { + gold_assert(r_type == elfcpp::R_X86_64_TLSDESC); + return 0; + } + + // Return the addend to use for a target specific relocation. + uint64_t + do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const; + + // 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. - off_t + section_size_type got_size() { gold_assert(this->got_ != NULL); return this->got_->data_size(); } + // Add a new reloc argument, returning the index in the vector. + size_t + add_tlsdesc_info(Sized_relobj<64, false>* object, unsigned int r_sym) + { + this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym)); + return this->tlsdesc_reloc_info_.size() - 1; + } + private: // The class which scans relocations. - struct Scan + 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, + local(Symbol_table* symtab, Layout* layout, Target_x86_64* target, Sized_relobj<64, false>* object, unsigned int data_shndx, Output_section* output_section, @@ -140,20 +228,49 @@ class Target_x86_64 : public Sized_target<64, false> const elfcpp::Sym<64, false>& lsym); inline void - global(const General_options& options, Symbol_table* symtab, - Layout* layout, Target_x86_64* target, + global(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); + inline bool + local_reloc_may_be_function_pointer(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 bool + global_reloc_may_be_function_pointer(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); + + inline bool + possible_function_pointer_reloc(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. @@ -161,7 +278,7 @@ class Target_x86_64 : public Sized_target<64, false> { public: Relocate() - : skip_call_tls_get_addr_(false) + : skip_call_tls_get_addr_(false), saw_tls_block_reloc_(false) { } ~Relocate() @@ -176,12 +293,12 @@ class Target_x86_64 : public Sized_target<64, false> // 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*, size_t relnum, - const elfcpp::Rela<64, false>&, + 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, - off_t); + section_size_type); private: // Do a TLS relocation. @@ -190,16 +307,18 @@ class Target_x86_64 : public Sized_target<64, false> 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, off_t); + unsigned char*, elfcpp::Elf_types<64>::Elf_Addr, + section_size_type); - // Do a TLS General-Dynamic to Local-Exec transition. + // 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, - off_t view_size); + elfcpp::Elf_types<64>::Elf_Addr, + section_size_type view_size); // Do a TLS General-Dynamic to Local-Exec transition. inline void @@ -208,7 +327,26 @@ class Target_x86_64 : public Sized_target<64, false> const elfcpp::Rela<64, false>&, unsigned int r_type, elfcpp::Elf_types<64>::Elf_Addr value, unsigned char* view, - off_t view_size); + 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 @@ -217,7 +355,7 @@ class Target_x86_64 : public Sized_target<64, false> const elfcpp::Rela<64, false>&, unsigned int r_type, elfcpp::Elf_types<64>::Elf_Addr value, unsigned char* view, - off_t view_size); + section_size_type view_size); // Do a TLS Initial-Exec to Local-Exec transition. static inline void @@ -226,11 +364,26 @@ class Target_x86_64 : public Sized_target<64, false> const elfcpp::Rela<64, false>&, unsigned int r_type, elfcpp::Elf_types<64>::Elf_Addr value, unsigned char* view, - off_t view_size); + 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 @@ -250,10 +403,22 @@ class Target_x86_64 : public Sized_target<64, false> 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, @@ -271,41 +436,72 @@ class Target_x86_64 : public Sized_target<64, false> Reloc_section* rela_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); - } + // Get the section to use for TLSDESC relocations. + Reloc_section* + rela_tlsdesc_section(Layout*) const; - // Copy a relocation against a global symbol. + // Add a potential copy relocation. void - copy_reloc(const General_options*, Symbol_table*, Layout*, - Sized_relobj<64, false>*, unsigned int, - Output_section*, Symbol*, const elfcpp::Rela<64, false>&); + 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 + }; + + // This type is used as the argument to the target specific + // relocation routines. The only target specific reloc is + // R_X86_64_TLSDESC against a local symbol. + struct Tlsdesc_info + { + Tlsdesc_info(Sized_relobj<64, false>* a_object, unsigned int a_r_sym) + : object(a_object), r_sym(a_r_sym) + { } + + // The object in which the local symbol is defined. + Sized_relobj<64, false>* object; + // The local symbol index in the object. + unsigned int r_sym; + }; + // The GOT section. Output_data_got<64, false>* got_; // The PLT section. Output_data_plt_x86_64* plt_; // The GOT PLT section. Output_data_space* got_plt_; + // The _GLOBAL_OFFSET_TABLE_ symbol. + Symbol* global_offset_table_; // The dynamic reloc section. Reloc_section* rela_dyn_; // Relocs saved to avoid a COPY reloc. - Copy_relocs<64, false>* copy_relocs_; + 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; + // Offset of the GOT entry for the TLS module index. unsigned int got_mod_index_offset_; + // We handle R_X86_64_TLSDESC against a local symbol as a target + // specific relocation. Here we store the object and local symbol + // index for the relocation. + std::vector tlsdesc_reloc_info_; + // True if the _TLS_MODULE_BASE_ symbol has been defined. + bool tls_base_symbol_defined_; }; const Target::Target_info Target_x86_64::x86_64_info = @@ -317,12 +513,29 @@ const Target::Target_info Target_x86_64::x86_64_info = 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 - 0x1000 // common_pagesize + 0x1000, // abi_pagesize (overridable by -z max-page-size) + 0x1000, // common_pagesize (overridable by -z common-page-size) + elfcpp::SHN_UNDEF, // small_common_shndx + elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx + 0, // small_common_section_flags + elfcpp::SHF_X86_64_LARGE, // large_common_section_flags + NULL, // attributes_section + NULL // attributes_vendor }; +// This is called when a new output section is created. This is where +// we handle the SHF_X86_64_LARGE. + +void +Target_x86_64::do_new_output_section(Output_section *os) const +{ + if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0) + os->set_is_large_section(); +} + // Get the GOT section, creating it if necessary. Output_data_got<64, false>* @@ -334,29 +547,35 @@ Target_x86_64::got_section(Symbol_table* symtab, Layout* layout) this->got_ = new Output_data_got<64, false>(); - layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, - elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, - this->got_); + Output_section* os; + os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_WRITE), + this->got_, false, true, true, + false); - // 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); - layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, - elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, - this->got_plt_); + this->got_plt_ = new Output_data_space(8, "** GOT PLT"); + os = layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_WRITE), + this->got_plt_, false, false, + false, true); // The first three entries are reserved. this->got_plt_->set_current_data_size(3 * 8); + // Those bytes can go into the relro segment. + layout->increase_relro(3 * 8); + // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. - 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); + this->global_offset_table_ = + symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, + Symbol_table::PREDEFINED, + this->got_plt_, + 0, 0, elfcpp::STT_OBJECT, + elfcpp::STB_LOCAL, + elfcpp::STV_HIDDEN, 0, + false, false); } return this->got_; @@ -370,9 +589,10 @@ Target_x86_64::rela_dyn_section(Layout* layout) if (this->rela_dyn_ == NULL) { gold_assert(layout != NULL); - this->rela_dyn_ = new Reloc_section(); + 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_); + elfcpp::SHF_ALLOC, this->rela_dyn_, true, + false, false, false); } return this->rela_dyn_; } @@ -384,21 +604,51 @@ 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_space*); + 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); - // Return the .rel.plt section data. + // 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 .rela.plt section data. const Reloc_section* - rel_plt() const + rela_plt() const { return this->rel_; } + // Return where the TLSDESC relocations should go. + Reloc_section* + rela_tlsdesc(Layout*); + 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; @@ -411,10 +661,12 @@ class Output_data_plt_x86_64 : public Output_section_data // 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() - { this->set_data_size((this->count_ + 1) * plt_entry_size); } + set_final_data_size(); // Write out the PLT data. void @@ -422,10 +674,17 @@ class Output_data_plt_x86_64 : public Output_section_data // The reloc section. Reloc_section* rel_; + // The TLSDESC relocs, if necessary. These must follow the regular + // PLT relocs. + Reloc_section* tlsdesc_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, @@ -433,20 +692,21 @@ class Output_data_plt_x86_64 : public Output_section_data // 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_plt_(got_plt), count_(0) + : Output_section_data(8), tlsdesc_rel_(NULL), got_(got), got_plt_(got_plt), + count_(0), tlsdesc_got_offset_(-1U) { - this->rel_ = new Reloc_section(); + this->rel_ = new Reloc_section(false); layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, - elfcpp::SHF_ALLOC, this->rel_); + elfcpp::SHF_ALLOC, this->rel_, true, + false, false, false); } void Output_data_plt_x86_64::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); + os->set_entsize(plt_entry_size); } // Add an entry to the PLT. @@ -462,7 +722,7 @@ Output_data_plt_x86_64::add_entry(Symbol* gsym) ++this->count_; - off_t got_offset = this->got_plt_->current_data_size(); + 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 @@ -479,6 +739,34 @@ Output_data_plt_x86_64::add_entry(Symbol* gsym) // appear in the relocations. } +// Return where the TLSDESC relocations should go, creating it if +// necessary. These follow the JUMP_SLOT relocations. + +Output_data_plt_x86_64::Reloc_section* +Output_data_plt_x86_64::rela_tlsdesc(Layout* layout) +{ + if (this->tlsdesc_rel_ == NULL) + { + this->tlsdesc_rel_ = new Reloc_section(false); + layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, + elfcpp::SHF_ALLOC, this->tlsdesc_rel_, + true, false, false, false); + gold_assert(this->tlsdesc_rel_->output_section() == + this->rel_->output_section()); + } + return this->tlsdesc_rel_; +} + +// Set the final size. +void +Output_data_plt_x86_64::set_final_data_size() +{ + unsigned int count = this->count_; + if (this->has_tlsdesc_entry()) + ++count; + this->set_data_size((count + 1) * plt_entry_size); +} + // The first entry in the PLT for an executable. unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] = @@ -504,6 +792,20 @@ unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] = 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. @@ -511,25 +813,35 @@ void Output_data_plt_x86_64::do_write(Output_file* of) { const off_t offset = this->offset(); - const off_t oview_size = this->data_size(); + 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 off_t got_size = this->got_plt_->data_size(); + 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(); + // 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)); + 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; @@ -563,37 +875,118 @@ Output_data_plt_x86_64::do_write(Output_file* of) elfcpp::Swap<64, false>::writeval(got_pov, plt_address + plt_offset + 6); } - gold_assert(pov - oview == oview_size); - gold_assert(got_pov - got_view == got_size); + 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 a PLT entry for a global symbol. +// Create the PLT section. void -Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout, - Symbol* gsym) +Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout) { - 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_x86_64(layout, this->got_plt_); + 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_); + this->plt_, false, false, false, false); } +} + +// Return the section for TLSDESC relocations. + +Target_x86_64::Reloc_section* +Target_x86_64::rela_tlsdesc_section(Layout* layout) const +{ + return this->plt_section()->rela_tlsdesc(layout); +} + +// Create a PLT entry for a global symbol. + +void +Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout, + Symbol* gsym) +{ + if (gsym->has_plt_offset()) + return; + + if (this->plt_ == NULL) + this->make_plt_section(symtab, layout); this->plt_->add_entry(gsym); } +// Define the _TLS_MODULE_BASE_ symbol in the TLS segment. + +void +Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout) +{ + if (this->tls_base_symbol_defined_) + return; + + Output_segment* tls_segment = layout->tls_segment(); + if (tls_segment != NULL) + { + bool is_exec = parameters->options().output_is_executable(); + symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL, + Symbol_table::PREDEFINED, + tls_segment, 0, 0, + elfcpp::STT_TLS, + elfcpp::STB_LOCAL, + elfcpp::STV_HIDDEN, 0, + (is_exec + ? Symbol::SEGMENT_END + : Symbol::SEGMENT_START), + true); + } + this->tls_base_symbol_defined_ = true; +} + +// Create the reserved PLT and GOT entries for the TLS descriptor resolver. + +void +Target_x86_64::reserve_tlsdesc_entries(Symbol_table* symtab, + Layout* layout) +{ + if (this->plt_ == NULL) + this->make_plt_section(symtab, layout); + + if (!this->plt_->has_tlsdesc_entry()) + { + // Allocate the TLSDESC_GOT entry. + Output_data_got<64, false>* got = this->got_section(symtab, layout); + unsigned int got_offset = got->add_constant(0); + + // Allocate the TLSDESC_PLT entry. + this->plt_->reserve_tlsdesc_entry(got_offset); + } +} + // Create a GOT entry for the TLS module index. unsigned int @@ -614,89 +1007,6 @@ Target_x86_64::got_mod_index_entry(Symbol_table* symtab, Layout* layout, 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_x86_64::copy_reloc(const General_options* options, - Symbol_table* symtab, - Layout* layout, - Sized_relobj<64, false>* object, - unsigned int data_shndx, - Output_section* output_section, - Symbol* gsym, - const elfcpp::Rela<64, false>& rela) -{ - Sized_symbol<64>* ssym; - ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(64) (gsym - SELECT_SIZE(64)); - - if (!Copy_relocs<64, 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<64, false>(); - this->copy_relocs_->save(ssym, object, data_shndx, output_section, rela); - } - else - { - // Allocate space for this symbol in the .bss section. - - elfcpp::Elf_types<64>::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); - - off_t dynbss_size = dynbss->current_data_size(); - dynbss_size = align_address(dynbss_size, align); - off_t 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* rela_dyn = this->rela_dyn_section(layout); - rela_dyn->add_global(ssym, elfcpp::R_X86_64_COPY, dynbss, offset, 0); - } -} - - // 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. @@ -706,7 +1016,7 @@ 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->output_is_shared()) + if (parameters->options().shared()) return tls::TLSOPT_NONE; switch (r_type) @@ -762,11 +1072,53 @@ Target_x86_64::Scan::unsupported_reloc_local(Sized_relobj<64, false>* object, 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, +Target_x86_64::Scan::local(Symbol_table* symtab, Layout* layout, Target_x86_64* target, Sized_relobj<64, false>* object, @@ -785,12 +1137,12 @@ Target_x86_64::Scan::local(const General_options&, 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_386_RELATIVE relocation so the dynamic loader can + // 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->output_is_position_independent()) + 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); @@ -807,18 +1159,35 @@ Target_x86_64::Scan::local(const General_options&, 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. 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()) + // 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()); - rela_dyn->add_local(object, r_sym, r_type, output_section, - data_shndx, reloc.get_r_offset(), - reloc.get_r_addend()); + 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; @@ -852,22 +1221,27 @@ Target_x86_64::Scan::local(const General_options&, // 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)) + 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->output_is_position_independent()) + 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), - 0); + 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 - rela_dyn->add_local(object, r_sym, r_type, - got, object->local_got_offset(r_sym), 0); + { + 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 @@ -897,7 +1271,7 @@ Target_x86_64::Scan::local(const General_options&, case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec case elfcpp::R_X86_64_TPOFF32: // Local-exec { - bool output_is_shared = parameters->output_is_shared(); + 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) @@ -910,23 +1284,57 @@ Target_x86_64::Scan::local(const General_options&, 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_tls_with_rela(object, r_sym, - lsym.get_st_shndx(), true, - target->rela_dyn_section(layout), - elfcpp::R_X86_64_DTPMOD64); + 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: - case elfcpp::R_X86_64_TLSDESC_CALL: - // FIXME: If not relaxing to LE, we need to generate - // a GOT entry with a R_x86_64_TLSDESC reloc. - if (optimized_type != tls::TLSOPT_TO_LE) + 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()); + if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC)) + { + unsigned int got_offset = got->add_constant(0); + got->add_constant(0); + object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC, + got_offset); + Reloc_section* rt = target->rela_tlsdesc_section(layout); + // We store the arguments we need in a vector, and + // use the index into the vector as the parameter + // to pass to the target specific routines. + uintptr_t intarg = target->add_tlsdesc_info(object, r_sym); + void* arg = reinterpret_cast(intarg); + rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg, + got, got_offset, 0); + } + } + else if (optimized_type != tls::TLSOPT_TO_LE) unsupported_reloc_local(object, r_type); break; + case elfcpp::R_X86_64_TLSDESC_CALL: + break; + case elfcpp::R_X86_64_TLSLD: // Local-dynamic if (optimized_type == tls::TLSOPT_NONE) { @@ -949,7 +1357,7 @@ Target_x86_64::Scan::local(const General_options&, 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->add_local_with_rela(object, r_sym, GOT_TYPE_TLS_OFFSET, target->rela_dyn_section(layout), elfcpp::R_X86_64_TPOFF64); } @@ -990,11 +1398,81 @@ Target_x86_64::Scan::unsupported_reloc_global(Sized_relobj<64, false>* object, object->name().c_str(), r_type, gsym->demangled_name().c_str()); } +// Returns true if this relocation type could be that of a function pointer. +inline bool +Target_x86_64::Scan::possible_function_pointer_reloc(unsigned int r_type) +{ + switch (r_type) + { + case elfcpp::R_X86_64_64: + case elfcpp::R_X86_64_32: + case elfcpp::R_X86_64_32S: + case elfcpp::R_X86_64_16: + case elfcpp::R_X86_64_8: + case elfcpp::R_X86_64_GOT64: + case elfcpp::R_X86_64_GOT32: + case elfcpp::R_X86_64_GOTPCREL64: + case elfcpp::R_X86_64_GOTPCREL: + case elfcpp::R_X86_64_GOTPLT64: + { + return true; + } + } + return false; +} + +// For safe ICF, scan a relocation for a local symbol to check if it +// corresponds to a function pointer being taken. In that case mark +// the function whose pointer was taken as not foldable. + +inline bool +Target_x86_64::Scan::local_reloc_may_be_function_pointer( + Symbol_table* , + Layout* , + Target_x86_64* , + Sized_relobj<64, false>* , + unsigned int , + Output_section* , + const elfcpp::Rela<64, false>& , + unsigned int r_type, + const elfcpp::Sym<64, false>&) +{ + // When building a shared library, do not fold any local symbols as it is + // not possible to distinguish pointer taken versus a call by looking at + // the relocation types. + return (parameters->options().shared() + || possible_function_pointer_reloc(r_type)); +} + +// For safe ICF, scan a relocation for a global symbol to check if it +// corresponds to a function pointer being taken. In that case mark +// the function whose pointer was taken as not foldable. + +inline bool +Target_x86_64::Scan::global_reloc_may_be_function_pointer( + Symbol_table*, + Layout* , + Target_x86_64* , + Sized_relobj<64, false>* , + unsigned int , + Output_section* , + const elfcpp::Rela<64, false>& , + unsigned int r_type, + Symbol* gsym) +{ + // When building a shared library, do not fold symbols whose visibility + // is hidden, internal or protected. + return ((parameters->options().shared() + && (gsym->visibility() == elfcpp::STV_INTERNAL + || gsym->visibility() == elfcpp::STV_PROTECTED + || gsym->visibility() == elfcpp::STV_HIDDEN)) + || possible_function_pointer_reloc(r_type)); +} + // Scan a relocation for a global symbol. inline void -Target_x86_64::Scan::global(const General_options& options, - Symbol_table* symtab, +Target_x86_64::Scan::global(Symbol_table* symtab, Layout* layout, Target_x86_64* target, Sized_relobj<64, false>* object, @@ -1025,15 +1503,15 @@ Target_x86_64::Scan::global(const General_options& options, // 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()) + if (gsym->is_from_dynobj() && !parameters->options().shared()) gsym->set_needs_dynsym_value(); } // Make a dynamic relocation if necessary. - if (gsym->needs_dynamic_reloc(true, false)) + if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF)) { - if (target->may_need_copy_reloc(gsym)) + if (gsym->may_need_copy_reloc()) { - target->copy_reloc(&options, symtab, layout, object, + target->copy_reloc(symtab, layout, object, data_shndx, output_section, gsym, reloc); } else if (r_type == elfcpp::R_X86_64_64 @@ -1047,6 +1525,7 @@ Target_x86_64::Scan::global(const General_options& options, } 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(), @@ -1065,16 +1544,19 @@ Target_x86_64::Scan::global(const General_options& options, if (gsym->needs_plt_entry()) target->make_plt_entry(symtab, layout, gsym); // Make a dynamic relocation if necessary. - bool is_function_call = (gsym->type() == elfcpp::STT_FUNC); - if (gsym->needs_dynamic_reloc(false, is_function_call)) + int flags = Symbol::NON_PIC_REF; + if (gsym->is_func()) + flags |= Symbol::FUNCTION_CALL; + if (gsym->needs_dynamic_reloc(flags)) { - if (target->may_need_copy_reloc(gsym)) + if (gsym->may_need_copy_reloc()) { - target->copy_reloc(&options, symtab, layout, object, + 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(), @@ -1093,21 +1575,23 @@ Target_x86_64::Scan::global(const General_options& options, // 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->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_preemptible()) - got->add_global_with_rela(gsym, rela_dyn, + 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)) - rela_dyn->add_global_relative(gsym, - elfcpp::R_X86_64_RELATIVE, - got, gsym->got_offset(), 0); + 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 @@ -1180,17 +1664,17 @@ Target_x86_64::Scan::global(const General_options& options, // dtv-relative offset. Output_data_got<64, false>* got = target->got_section(symtab, layout); - got->add_global_tls_with_rela(gsym, - target->rela_dyn_section(layout), - elfcpp::R_X86_64_DTPMOD64, - elfcpp::R_X86_64_DTPOFF64); + 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->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET, target->rela_dyn_section(layout), elfcpp::R_X86_64_TPOFF64); } @@ -1199,13 +1683,35 @@ Target_x86_64::Scan::global(const General_options& options, break; case elfcpp::R_X86_64_GOTPC32_TLSDESC: - case elfcpp::R_X86_64_TLSDESC_CALL: - // FIXME: If not relaxing to LE, we need to generate - // DTPMOD64 and DTPOFF64, or TLSDESC, relocs. - if (optimized_type != tls::TLSOPT_TO_LE) + 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); + Reloc_section *rt = target->rela_tlsdesc_section(layout); + got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC, rt, + elfcpp::R_X86_64_TLSDESC, 0); + } + else if (optimized_type == tls::TLSOPT_TO_IE) + { + // Create a GOT entry for the tp-relative offset. + Output_data_got<64, false>* got + = target->got_section(symtab, layout); + got->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET, + target->rela_dyn_section(layout), + elfcpp::R_X86_64_TPOFF64); + } + else if (optimized_type != tls::TLSOPT_TO_LE) unsupported_reloc_global(object, r_type, gsym); break; + case elfcpp::R_X86_64_TLSDESC_CALL: + break; + case elfcpp::R_X86_64_TLSLD: // Local-dynamic if (optimized_type == tls::TLSOPT_NONE) { @@ -1227,7 +1733,7 @@ Target_x86_64::Scan::global(const General_options& options, // 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->add_global_with_rela(gsym, GOT_TYPE_TLS_OFFSET, target->rela_dyn_section(layout), elfcpp::R_X86_64_TPOFF64); } @@ -1237,7 +1743,7 @@ Target_x86_64::Scan::global(const General_options& options, case elfcpp::R_X86_64_TPOFF32: // Local-exec layout->set_has_static_tls(); - if (parameters->output_is_shared()) + if (parameters->options().shared()) unsupported_reloc_local(object, r_type); break; @@ -1257,11 +1763,44 @@ Target_x86_64::Scan::global(const General_options& options, } } +void +Target_x86_64::gc_process_relocs(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>( + 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, +Target_x86_64::scan_relocs(Symbol_table* symtab, Layout* layout, Sized_relobj<64, false>* object, unsigned int data_shndx, @@ -1282,7 +1821,6 @@ Target_x86_64::scan_relocs(const General_options& options, gold::scan_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA, Target_x86_64::Scan>( - options, symtab, layout, this, @@ -1299,51 +1837,48 @@ Target_x86_64::scan_relocs(const General_options& options, // Finalize the sections. void -Target_x86_64::do_finalize_sections(Layout* layout) +Target_x86_64::do_finalize_sections( + Layout* layout, + const Input_objects*, + Symbol_table* symtab) { + const Reloc_section* rel_plt = (this->plt_ == NULL + ? NULL + : this->plt_->rela_plt()); + layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt, + this->rela_dyn_, true, false); + // Fill in some more dynamic tags. Output_data_dynamic* const odyn = layout->dynamic_data(); if (odyn != NULL) { - if (this->got_plt_ != NULL) - odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_); - - if (this->plt_ != NULL) + if (this->plt_ != NULL + && this->plt_->output_section() != NULL + && this->plt_->has_tlsdesc_entry()) { - 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->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->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); + unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset(); + unsigned int got_offset = this->plt_->get_tlsdesc_got_offset(); + this->got_->finalize_data_size(); + odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT, + this->plt_, plt_offset); + odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT, + this->got_, got_offset); } } // Emit any relocs we saved in an attempt to avoid generating COPY // relocs. - if (this->copy_relocs_ == NULL) - return; - if (this->copy_relocs_->any_to_emit()) + if (this->copy_relocs_.any_saved_relocs()) + this->copy_relocs_.emit(this->rela_dyn_section(layout)); + + // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of + // the .got.plt section. + Symbol* sym = this->global_offset_table_; + if (sym != NULL) { - Reloc_section* rela_dyn = this->rela_dyn_section(layout); - this->copy_relocs_->emit(rela_dyn); + uint64_t data_size = this->got_plt_->current_data_size(); + symtab->get_sized_symbol<64>(sym)->set_symsize(data_size); } - delete this->copy_relocs_; - this->copy_relocs_ = NULL; } // Perform a relocation. @@ -1351,6 +1886,7 @@ Target_x86_64::do_finalize_sections(Layout* layout) 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, @@ -1358,11 +1894,12 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo, const Symbol_value<64>* psymval, unsigned char* view, elfcpp::Elf_types<64>::Elf_Addr address, - off_t view_size) + section_size_type view_size) { if (this->skip_call_tls_get_addr_) { - if (r_type != elfcpp::R_X86_64_PLT32 + if ((r_type != elfcpp::R_X86_64_PLT32 + && r_type != elfcpp::R_X86_64_PC32) || gsym == NULL || strcmp(gsym->name(), "__tls_get_addr") != 0) { @@ -1379,10 +1916,10 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo, // Pick the value to use for symbols defined in shared objects. Symbol_value<64> symval; if (gsym != NULL - && (gsym->is_from_dynobj() - || (parameters->output_is_shared() - && gsym->is_preemptible())) - && gsym->has_plt_offset()) + && 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()); @@ -1407,14 +1944,15 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo, case elfcpp::R_X86_64_GOTPCREL64: if (gsym != NULL) { - gold_assert(gsym->has_got_offset()); - got_offset = gsym->got_offset() - target->got_size(); + 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_offset = object->local_got_offset(r_sym) - target->got_size(); + 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; @@ -1480,7 +2018,10 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo, case elfcpp::R_X86_64_PLT32: gold_assert(gsym == NULL || gsym->has_plt_offset() - || gsym->final_value_is_known()); + || 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(). @@ -1607,7 +2148,7 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, const Symbol_value<64>* psymval, unsigned char* view, elfcpp::Elf_types<64>::Elf_Addr address, - off_t view_size) + section_size_type view_size) { Output_segment* tls_segment = relinfo->layout->tls_segment(); @@ -1617,15 +2158,14 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, elfcpp::Elf_types<64>::Elf_Addr value = psymval->value(relinfo->object, 0); const bool is_final = (gsym == NULL - ? !parameters->output_is_position_independent() + ? !parameters->options().shared() : 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 - 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); @@ -1636,24 +2176,28 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, } 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_tls_got_offset(true)); - got_offset = gsym->tls_got_offset(true) - target->got_size(); + 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_tls_got_offset(r_sym, true)); - got_offset = (object->local_tls_got_offset(r_sym, true) + 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, - got_offset, view, view_size); + value, view, address, view_size); break; } else if (optimized_type == tls::TLSOPT_NONE) @@ -1670,7 +2214,63 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, _("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); @@ -1695,17 +2295,32 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, break; case elfcpp::R_X86_64_DTPOFF32: - gold_assert(tls_segment != NULL); if (optimized_type == tls::TLSOPT_TO_LE) - value -= tls_segment->memsz(); - Relocate_functions<64, false>::rela32(view, value, 0); + { + // 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: - gold_assert(tls_segment != NULL); if (optimized_type == tls::TLSOPT_TO_LE) - value -= tls_segment->memsz(); - Relocate_functions<64, false>::rela64(view, value, 0); + { + // 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 @@ -1724,14 +2339,16 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, unsigned int got_offset; if (gsym != NULL) { - gold_assert(gsym->has_got_offset()); - got_offset = gsym->got_offset() - target->got_size(); + 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_offset = (object->local_got_offset(r_sym) + 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; @@ -1745,7 +2362,7 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, case elfcpp::R_X86_64_TPOFF32: // Local-exec value -= tls_segment->memsz(); - Relocate_functions<64, false>::rela32(view, value, 0); + Relocate_functions<64, false>::rela32(view, value, addend); break; } } @@ -1756,12 +2373,13 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, inline void Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo, size_t relnum, - Output_segment* tls_segment, + Output_segment*, const elfcpp::Rela<64, false>& rela, unsigned int, elfcpp::Elf_types<64>::Elf_Addr value, unsigned char* view, - off_t view_size) + 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 @@ -1777,8 +2395,8 @@ Target_x86_64::Relocate::tls_gd_to_ie(const Relocate_info<64, false>* relinfo, memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 16); - value -= tls_segment->memsz(); - Relocate_functions<64, false>::rela32(view + 8, value, 0); + 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. @@ -1796,7 +2414,7 @@ Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo, unsigned int, elfcpp::Elf_types<64>::Elf_Addr value, unsigned char* view, - off_t view_size) + section_size_type view_size) { // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; // .word 0x6666; rex64; call __tls_get_addr @@ -1820,6 +2438,84 @@ Target_x86_64::Relocate::tls_gd_to_le(const Relocate_info<64, false>* relinfo, 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, @@ -1828,7 +2524,7 @@ Target_x86_64::Relocate::tls_ld_to_le(const Relocate_info<64, false>* relinfo, unsigned int, elfcpp::Elf_types<64>::Elf_Addr, unsigned char* view, - off_t view_size) + section_size_type view_size) { // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt; // ... leq foo@dtpoff(%rax),%reg @@ -1860,7 +2556,7 @@ Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo, unsigned int, elfcpp::Elf_types<64>::Elf_Addr value, unsigned char* view, - off_t view_size) + section_size_type view_size) { // We need to examine the opcodes to figure out which instruction we // are looking at. @@ -1908,15 +2604,17 @@ Target_x86_64::Relocate::tls_ie_to_le(const Relocate_info<64, false>* relinfo, // 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, - off_t view_size) +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); @@ -1930,7 +2628,146 @@ Target_x86_64::relocate_section(const Relocate_info<64, false>* relinfo, needs_special_offset_handling, view, address, - view_size); + 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(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>( + 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 @@ -1949,14 +2786,14 @@ Target_x86_64::do_dynsym_value(const Symbol* gsym) const // the specified length. std::string -Target_x86_64::do_code_fill(off_t length) +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<64, false>::writeval(jmp + 1, length - 5); + elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5); return (std::string(reinterpret_cast(&jmp[0]), 5) + std::string(length - 5, '\0')); } @@ -1964,40 +2801,40 @@ Target_x86_64::do_code_fill(off_t length) // 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 + 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] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi + const char nop7[7] = { 0x0f, 0x1f, 0x80, 0x00, // nopl 0L(%rax) 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 + 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] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi - 0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi + const char nop10[10] = { 0x66, 0x2e, 0x0f, 0x1f, // nopw %cs:0L(%rax,%rax,1) + 0x84, 0x00, 0x00, 0x00, 0x00, 0x00 }; - const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi - 0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi + 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] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi - 0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi + 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] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi - 0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi - 0x27, 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] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi - 0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi - 0xbc, 0x27, 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] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15 - 0x90, 0x90, 0x90, 0x90, // nop,nop,nop,... - 0x90, 0x90, 0x90, 0x90, - 0x90, 0x90, 0x90 }; + 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, @@ -2008,33 +2845,102 @@ Target_x86_64::do_code_fill(off_t length) return std::string(nops[length], length); } +// Return the addend to use for a target specific relocation. The +// only target specific relocation is R_X86_64_TLSDESC for a local +// symbol. We want to set the addend is the offset of the local +// symbol in the TLS segment. + +uint64_t +Target_x86_64::do_reloc_addend(void* arg, unsigned int r_type, + uint64_t) const +{ + gold_assert(r_type == elfcpp::R_X86_64_TLSDESC); + uintptr_t intarg = reinterpret_cast(arg); + gold_assert(intarg < this->tlsdesc_reloc_info_.size()); + const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]); + const Symbol_value<64>* psymval = ti.object->local_symbol(ti.r_sym); + gold_assert(psymval->is_tls_symbol()); + // The value of a TLS symbol is the offset in the TLS segment. + return psymval->value(ti.object, 0); +} + +// FNOFFSET in section SHNDX in OBJECT is the start of a function +// compiled with -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 + // lea NN(%rsp),%r11 + else if ((this->match_view(view, view_size, fnoffset, + "\x4c\x8d\x94\x24", 4) + || this->match_view(view, view_size, fnoffset, + "\x4c\x8d\x9c\x24", 4)) + && fnsize > 8) + { + // This is loading an offset from the stack pointer for a + // comparison. The offset is negative, so we decrease the + // offset by the amount of space we need for the stack. This + // means we will avoid calling __morestack if there happens to + // be plenty of space on the stack already. + unsigned char* pval = view + fnoffset + 4; + uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval); + val -= parameters->options().split_stack_adjust_size(); + elfcpp::Swap_unaligned<32, false>::writeval(pval, val); + } + else + { + if (!object->has_no_split_stack()) + object->error(_("failed to match split-stack sequence at " + "section %u offset %0zx"), + shndx, static_cast(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 +class Target_selector_x86_64 : public Target_selector_freebsd { public: Target_selector_x86_64() - : Target_selector(elfcpp::EM_X86_64, 64, false) + : Target_selector_freebsd(elfcpp::EM_X86_64, 64, false, "elf64-x86-64", + "elf64-x86-64-freebsd") { } Target* - recognize(int machine, int osabi, int abiversion); + do_instantiate_target() + { return new Target_x86_64(); } - private: - Target_x86_64* target_; }; -// Recognize an x86_64 object file when we already know that the machine -// number is EM_X86_64. - -Target* -Target_selector_x86_64::recognize(int, int, int) -{ - if (this->target_ == NULL) - this->target_ = new Target_x86_64(); - return this->target_; -} - Target_selector_x86_64 target_selector_x86_64; } // End anonymous namespace.