diff options
Diffstat (limited to 'binutils-2.19/gold/x86_64.cc')
| -rw-r--r-- | binutils-2.19/gold/x86_64.cc | 665 |
1 files changed, 501 insertions, 164 deletions
diff --git a/binutils-2.19/gold/x86_64.cc b/binutils-2.19/gold/x86_64.cc index 2daa9bf..e9dd5ae 100644 --- a/binutils-2.19/gold/x86_64.cc +++ b/binutils-2.19/gold/x86_64.cc @@ -1,6 +1,6 @@ // x86_64.cc -- x86_64 target support for gold. -// Copyright 2006, 2007, 2008 Free Software Foundation, Inc. +// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc. // Written by Ian Lance Taylor <iant@google.com>. // This file is part of gold. @@ -37,6 +37,9 @@ #include "target-reloc.h" #include "target-select.h" #include "tls.h" +#include "freebsd.h" +#include "gc.h" +#include "icf.h" namespace { @@ -52,7 +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 @@ -60,16 +63,44 @@ class Target_x86_64 : public Sized_target<64, false> typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section; Target_x86_64() - : Sized_target<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) + : 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, @@ -83,7 +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. @@ -100,12 +131,12 @@ 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, - section_size_type view_size); + 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, + scan_relocatable_relocs(Symbol_table* symtab, Layout* layout, Sized_relobj<64, false>* object, unsigned int data_shndx, @@ -139,9 +170,30 @@ class Target_x86_64 : public Sized_target<64, false> // 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. section_size_type got_size() @@ -150,6 +202,14 @@ class Target_x86_64 : public Sized_target<64, false> 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. class Scan @@ -160,8 +220,7 @@ class Target_x86_64 : public Sized_target<64, 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, @@ -169,14 +228,33 @@ 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); @@ -188,6 +266,9 @@ class Target_x86_64 : public Sized_target<64, false> 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_; }; @@ -212,8 +293,8 @@ 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, @@ -330,7 +411,7 @@ class Target_x86_64 : public Sized_target<64, false> void make_plt_entry(Symbol_table*, Layout*, Symbol*); - // Define the _TLS_MODULE_BASE_ symbol at the end of the TLS segment. + // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. void define_tls_base_symbol(Symbol_table*, Layout*); @@ -355,16 +436,9 @@ 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->options().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; // Add a potential copy relocation. void @@ -391,12 +465,29 @@ class Target_x86_64 : public Sized_target<64, false> 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. @@ -405,6 +496,10 @@ class Target_x86_64 : public Sized_target<64, false> Output_data_space* dynbss_; // Offset of the GOT entry for the TLS module index. unsigned int got_mod_index_offset_; + // We handle R_X86_64_TLSDESC against a local symbol as a target + // specific relocation. Here we store the object and local symbol + // index for the relocation. + std::vector<Tlsdesc_info> tlsdesc_reloc_info_; // True if the _TLS_MODULE_BASE_ symbol has been defined. bool tls_base_symbol_defined_; }; @@ -422,9 +517,25 @@ const Target::Target_info Target_x86_64::x86_64_info = "/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) + 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>* @@ -440,30 +551,31 @@ Target_x86_64::got_section(Symbol_table* symtab, Layout* layout) os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, (elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE), - this->got_); - os->set_is_relro(); + 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, "** GOT PLT"); - os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, + os = layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, (elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE), - this->got_plt_); - os->set_is_relro(); + 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("_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_; @@ -479,7 +591,8 @@ Target_x86_64::rela_dyn_section(Layout* layout) 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_); + elfcpp::SHF_ALLOC, this->rela_dyn_, true, + false, false, false); } return this->rela_dyn_; } @@ -518,11 +631,15 @@ class Output_data_plt_x86_64 : public Output_section_data get_tlsdesc_plt_offset() const { return (this->count_ + 1) * plt_entry_size; } - // Return the .rel.plt section data. + // 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); @@ -557,6 +674,9 @@ 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. @@ -574,20 +694,19 @@ class Output_data_plt_x86_64 : public Output_section_data 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) + : Output_section_data(8), tlsdesc_rel_(NULL), 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_); + 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. @@ -620,6 +739,24 @@ 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() @@ -777,10 +914,18 @@ Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout) 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 @@ -796,7 +941,7 @@ Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout, this->plt_->add_entry(gsym); } -// Define the _TLS_MODULE_BASE_ symbol at the end of the TLS segment. +// Define the _TLS_MODULE_BASE_ symbol in the TLS segment. void Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout) @@ -807,12 +952,17 @@ Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout) 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, - Symbol::SEGMENT_END, true); + (is_exec + ? Symbol::SEGMENT_END + : Symbol::SEGMENT_START), + true); } this->tls_base_symbol_defined_ = true; } @@ -954,6 +1104,7 @@ Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type) // 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; @@ -967,8 +1118,7 @@ Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type) // 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, @@ -1162,18 +1312,21 @@ 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()); - 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); + if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC)) + { + unsigned int got_offset = got->add_constant(0); + got->add_constant(0); + object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC, + got_offset); + Reloc_section* rt = target->rela_tlsdesc_section(layout); + // We store the arguments we need in a vector, and + // use the index into the vector as the parameter + // to pass to the target specific routines. + uintptr_t intarg = target->add_tlsdesc_info(object, r_sym); + void* arg = reinterpret_cast<void*>(intarg); + rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg, + got, got_offset, 0); + } } else if (optimized_type != tls::TLSOPT_TO_LE) unsupported_reloc_local(object, r_type); @@ -1245,11 +1398,80 @@ 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 +// only if the target is not position-independent code. +inline bool +Target_x86_64::Scan::possible_function_pointer_reloc(unsigned int r_type) +{ + if (parameters->options().shared()) + return false; + + 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: + { + 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&, - Symbol_table* symtab, +Target_x86_64::Scan::global(Symbol_table* symtab, Layout* layout, Target_x86_64* target, Sized_relobj<64, false>* object, @@ -1286,7 +1508,7 @@ Target_x86_64::Scan::global(const General_options&, // Make a dynamic relocation if necessary. if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF)) { - if (target->may_need_copy_reloc(gsym)) + if (gsym->may_need_copy_reloc()) { target->copy_reloc(symtab, layout, object, data_shndx, output_section, gsym, reloc); @@ -1322,11 +1544,11 @@ Target_x86_64::Scan::global(const General_options&, 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) + 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(symtab, layout, object, data_shndx, output_section, gsym, reloc); @@ -1469,8 +1691,8 @@ Target_x86_64::Scan::global(const General_options&, // 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), + 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) @@ -1540,11 +1762,44 @@ Target_x86_64::Scan::global(const General_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, @@ -1565,7 +1820,6 @@ 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, @@ -1582,47 +1836,32 @@ 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->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); + 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); } } @@ -1630,6 +1869,15 @@ Target_x86_64::do_finalize_sections(Layout* layout) // relocs. if (this->copy_relocs_.any_saved_relocs()) this->copy_relocs_.emit(this->rela_dyn_section(layout)); + + // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of + // the .got.plt section. + Symbol* sym = this->global_offset_table_; + if (sym != NULL) + { + uint64_t data_size = this->got_plt_->current_data_size(); + symtab->get_sized_symbol<64>(sym)->set_symsize(data_size); + } } // Perform a relocation. @@ -1637,6 +1885,7 @@ 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, @@ -1648,7 +1897,8 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo, { 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) { @@ -1907,7 +2157,7 @@ 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->options().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); @@ -2044,7 +2294,6 @@ 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) { // This relocation type is used in debugging information. @@ -2052,18 +2301,23 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, // haven't seen a TLSLD reloc, then we assume we should not // optimize this reloc. if (this->saw_tls_block_reloc_) - value -= tls_segment->memsz(); + { + 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) { // See R_X86_64_DTPOFF32, just above, for why we test this. if (this->saw_tls_block_reloc_) - value -= tls_segment->memsz(); + { + gold_assert(tls_segment != NULL); + value -= tls_segment->memsz(); + } } Relocate_functions<64, false>::rela64(view, value, addend); break; @@ -2349,15 +2603,17 @@ 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, - section_size_type 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); @@ -2371,7 +2627,8 @@ 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 @@ -2446,8 +2703,7 @@ Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc( // Scan the relocs during a relocatable link. void -Target_x86_64::scan_relocatable_relocs(const General_options& options, - Symbol_table* symtab, +Target_x86_64::scan_relocatable_relocs(Symbol_table* symtab, Layout* layout, Sized_relobj<64, false>* object, unsigned int data_shndx, @@ -2467,7 +2723,6 @@ Target_x86_64::scan_relocatable_relocs(const General_options& options, gold::scan_relocatable_relocs<64, false, elfcpp::SHT_RELA, Scan_relocatable_relocs>( - options, symtab, layout, object, @@ -2545,40 +2800,40 @@ Target_x86_64::do_code_fill(section_size_type length) const // 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, @@ -2589,18 +2844,100 @@ Target_x86_64::do_code_fill(section_size_type length) const return std::string(nops[length], length); } +// Return the addend to use for a target specific relocation. The +// only target specific relocation is R_X86_64_TLSDESC for a local +// symbol. We want to set the addend is the offset of the local +// symbol in the TLS segment. + +uint64_t +Target_x86_64::do_reloc_addend(void* arg, unsigned int r_type, + uint64_t) const +{ + gold_assert(r_type == elfcpp::R_X86_64_TLSDESC); + uintptr_t intarg = reinterpret_cast<uintptr_t>(arg); + gold_assert(intarg < this->tlsdesc_reloc_info_.size()); + const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]); + const Symbol_value<64>* psymval = ti.object->local_symbol(ti.r_sym); + gold_assert(psymval->is_tls_symbol()); + // The value of a TLS symbol is the offset in the TLS segment. + return psymval->value(ti.object, 0); +} + +// FNOFFSET in section SHNDX in OBJECT is the start of a function +// compiled with -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<size_t>(fnoffset)); + return; + } + + // We have to change the function so that it calls + // __morestack_non_split instead of __morestack. The former will + // allocate additional stack space. + *from = "__morestack"; + *to = "__morestack_non_split"; +} + // The selector for x86_64 object files. -class Target_selector_x86_64 : public Target_selector +class Target_selector_x86_64 : public Target_selector_freebsd { public: Target_selector_x86_64() - : Target_selector(elfcpp::EM_X86_64, 64, false, "elf64-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; |