X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gold%2Fx86_64.cc;h=5ba15c45d0e2512e37674fd565321bce04c81842;hb=29b2c556d2655b11483d07468d1eaf2dff1395ce;hp=00fbf3fc1fe84dae6856fc2262ad1d71aae58960;hpb=91d6fa6a035cc7d0b7be5c99c194a64cb80924b0;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/x86_64.cc b/gold/x86_64.cc index 00fbf3fc1f..5ba15c45d0 100644 --- a/gold/x86_64.cc +++ b/gold/x86_64.cc @@ -1,6 +1,6 @@ // x86_64.cc -- x86_64 target support for gold. -// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc. +// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -39,13 +39,122 @@ #include "tls.h" #include "freebsd.h" #include "gc.h" +#include "icf.h" namespace { using namespace gold; -class Output_data_plt_x86_64; +// A class to handle the PLT data. + +class Output_data_plt_x86_64 : public Output_section_data +{ + public: + typedef Output_data_reloc Reloc_section; + + Output_data_plt_x86_64(Symbol_table*, Layout*, Output_data_got<64, false>*, + Output_data_space*); + + // Add an entry to the PLT. + void + add_entry(Symbol* gsym); + + // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. + unsigned int + add_local_ifunc_entry(Sized_relobj<64, false>* relobj, + unsigned int local_sym_index); + + // 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. + Reloc_section* + rela_plt() + { return this->rel_; } + + // Return where the TLSDESC relocations should go. + Reloc_section* + rela_tlsdesc(Layout*); + + // Return the number of PLT entries. + unsigned int + entry_count() const + { return this->count_; } + + // Return the offset of the first non-reserved PLT entry. + static unsigned int + first_plt_entry_offset() + { return plt_entry_size; } + + // Return the size of a PLT entry. + static unsigned int + get_plt_entry_size() + { return plt_entry_size; } + + protected: + void + do_adjust_output_section(Output_section* os); + + // Write to a map file. + void + do_print_to_mapfile(Mapfile* mapfile) const + { mapfile->print_output_data(this, _("** PLT")); } + + private: + // The size of an entry in the PLT. + static const int plt_entry_size = 16; + + // The first entry in the PLT. + // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same + // procedure linkage table for both programs and shared objects." + static unsigned char first_plt_entry[plt_entry_size]; + + // Other entries in the PLT for an executable. + static unsigned char plt_entry[plt_entry_size]; + + // The reserved TLSDESC entry in the PLT for an executable. + static unsigned char tlsdesc_plt_entry[plt_entry_size]; + + // Set the final size. + void + set_final_data_size(); + + // Write out the PLT data. + void + do_write(Output_file*); + + // The reloc section. + Reloc_section* rel_; + // The 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_; +}; // The x86_64 target class. // See the ABI at @@ -63,11 +172,27 @@ class Target_x86_64 : public Target_freebsd<64, false> Target_x86_64() : Target_freebsd<64, false>(&x86_64_info), - got_(NULL), plt_(NULL), got_plt_(NULL), rela_dyn_(NULL), + got_(NULL), plt_(NULL), got_plt_(NULL), got_tlsdesc_(NULL), + global_offset_table_(NULL), rela_dyn_(NULL), copy_relocs_(elfcpp::R_X86_64_COPY), dynbss_(NULL), - got_mod_index_offset_(-1U), tls_base_symbol_defined_(false) + 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(); } + + virtual bool + can_icf_inline_merge_sections () const + { return true; } + // Hook for a new output section. void do_new_output_section(Output_section*) const; @@ -161,7 +286,30 @@ class Target_x86_64 : public Target_freebsd<64, false> do_is_defined_by_abi(const Symbol* sym) const { return strcmp(sym->name(), "__tls_get_addr") == 0; } - // Adjust -fstack-split code which calls non-stack-split code. + // 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; + + // Return the PLT section. + Output_data* + do_plt_section_for_global(const Symbol*) const + { return this->plt_section(); } + + Output_data* + do_plt_section_for_local(const Relobj*, unsigned int) const + { return this->plt_section(); } + + // Adjust -fsplit-stack code which calls non-split-stack code. void do_calls_non_split(Relobj* object, unsigned int shndx, section_offset_type fnoffset, section_size_type fnsize, @@ -170,12 +318,41 @@ class Target_x86_64 : public Target_freebsd<64, false> // Return the size of the GOT section. section_size_type - got_size() + got_size() const { gold_assert(this->got_ != NULL); return this->got_->data_size(); } + // Return the number of entries in the GOT. + unsigned int + got_entry_count() const + { + if (this->got_ == NULL) + return 0; + return this->got_size() / 8; + } + + // Return the number of entries in the PLT. + unsigned int + plt_entry_count() const; + + // Return the offset of the first non-reserved PLT entry. + unsigned int + first_plt_entry_offset() const; + + // Return the size of each PLT entry. + unsigned int + plt_entry_size() const; + + // 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 @@ -185,6 +362,9 @@ class Target_x86_64 : public Target_freebsd<64, false> : issued_non_pic_error_(false) { } + static inline int + get_reference_flags(unsigned int r_type); + inline void local(Symbol_table* symtab, Layout* layout, Target_x86_64* target, Sized_relobj<64, false>* object, @@ -201,6 +381,26 @@ class Target_x86_64 : public Target_freebsd<64, false> 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); @@ -212,6 +412,12 @@ class Target_x86_64 : public Target_freebsd<64, false> void check_non_pic(Relobj*, unsigned int r_type); + inline bool + possible_function_pointer_reloc(unsigned int r_type); + + bool + reloc_needs_plt_for_ifunc(Sized_relobj<64, false>*, unsigned int r_type); + // Whether we have issued an error about a non-PIC compilation. bool issued_non_pic_error_; }; @@ -221,7 +427,7 @@ class Target_x86_64 : public Target_freebsd<64, false> { public: Relocate() - : skip_call_tls_get_addr_(false), saw_tls_block_reloc_(false) + : skip_call_tls_get_addr_(false) { } ~Relocate() @@ -312,12 +518,6 @@ class Target_x86_64 : public Target_freebsd<64, false> // 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, @@ -346,6 +546,14 @@ class Target_x86_64 : public Target_freebsd<64, false> return this->got_plt_; } + // Get the GOT section for TLSDESC entries. + Output_data_got<64, false>* + got_tlsdesc_section() const + { + gold_assert(this->got_tlsdesc_ != NULL); + return this->got_tlsdesc_; + } + // Create the PLT section. void make_plt_section(Symbol_table* symtab, Layout* layout); @@ -354,6 +562,12 @@ class Target_x86_64 : public Target_freebsd<64, false> void make_plt_entry(Symbol_table*, Layout*, Symbol*); + // Create a PLT entry for a local STT_GNU_IFUNC symbol. + void + make_local_ifunc_plt_entry(Symbol_table*, Layout*, + Sized_relobj<64, false>* relobj, + unsigned int local_sym_index); + // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. void define_tls_base_symbol(Symbol_table*, Layout*); @@ -379,6 +593,10 @@ class Target_x86_64 : public Target_freebsd<64, false> Reloc_section* rela_dyn_section(Layout*); + // Get the section to use for TLSDESC relocations. + Reloc_section* + rela_tlsdesc_section(Layout*) const; + // Add a potential copy relocation. void copy_reloc(Symbol_table* symtab, Layout* layout, @@ -396,6 +614,10 @@ class Target_x86_64 : public Target_freebsd<64, false> // general Target structure. static const Target::Target_info x86_64_info; + // The types of GOT entries needed for this platform. + // These values are exposed to the ABI in an incremental link. + // Do not renumber existing values without changing the version + // number of the .gnu_incremental_inputs section. enum Got_type { GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol @@ -404,12 +626,31 @@ class Target_x86_64 : public Target_freebsd<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 GOT section for TLSDESC relocations. + Output_data_got<64, false>* got_tlsdesc_; + // The _GLOBAL_OFFSET_TABLE_ symbol. + Symbol* global_offset_table_; // The dynamic reloc section. Reloc_section* rela_dyn_; // Relocs saved to avoid a COPY reloc. @@ -418,6 +659,10 @@ class Target_x86_64 : public Target_freebsd<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_reloc_info_; // True if the _TLS_MODULE_BASE_ symbol has been defined. bool tls_base_symbol_defined_; }; @@ -448,7 +693,7 @@ const Target::Target_info Target_x86_64::x86_64_info = // we handle the SHF_X86_64_LARGE. void -Target_x86_64::do_new_output_section(Output_section *os) const +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(); @@ -465,34 +710,43 @@ Target_x86_64::got_section(Symbol_table* symtab, Layout* layout) this->got_ = new Output_data_got<64, false>(); - Output_section* os; - os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, - (elfcpp::SHF_ALLOC - | elfcpp::SHF_WRITE), - this->got_, false); - os->set_is_relro(); - - // The old GNU linker creates a .got.plt section. We just - // create another set of data in the .got section. Note that we - // always create a PLT if we create a GOT, although the PLT - // might be empty. + layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_WRITE), + this->got_, ORDER_RELRO_LAST, + true); + this->got_plt_ = new Output_data_space(8, "** GOT PLT"); - os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, - (elfcpp::SHF_ALLOC - | elfcpp::SHF_WRITE), - this->got_plt_, false); - os->set_is_relro(); + layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_WRITE), + this->got_plt_, ORDER_NON_RELRO_FIRST, + false); // 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); + + // If there are any TLSDESC relocations, they get GOT entries in + // .got.plt after the jump slot entries. + this->got_tlsdesc_ = new Output_data_got<64, false>(); + layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, + (elfcpp::SHF_ALLOC + | elfcpp::SHF_WRITE), + this->got_tlsdesc_, + ORDER_NON_RELRO_FIRST, false); } return this->got_; @@ -508,107 +762,45 @@ 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_, true); + elfcpp::SHF_ALLOC, this->rela_dyn_, + ORDER_DYNAMIC_RELOCS, false); } return this->rela_dyn_; } -// A class to handle the PLT data. - -class Output_data_plt_x86_64 : public Output_section_data -{ - public: - typedef Output_data_reloc Reloc_section; - - Output_data_plt_x86_64(Layout*, Output_data_got<64, false>*, - Output_data_space*); - - // Add an entry to the PLT. - void - add_entry(Symbol* gsym); - - // Add the reserved TLSDESC_PLT entry to the PLT. - void - reserve_tlsdesc_entry(unsigned int got_offset) - { this->tlsdesc_got_offset_ = got_offset; } - - // Return true if a TLSDESC_PLT entry has been reserved. - bool - has_tlsdesc_entry() const - { return this->tlsdesc_got_offset_ != -1U; } - - // Return the GOT offset for the reserved TLSDESC_PLT entry. - unsigned int - get_tlsdesc_got_offset() const - { return this->tlsdesc_got_offset_; } - - // Return the offset of the reserved TLSDESC_PLT entry. - unsigned int - get_tlsdesc_plt_offset() const - { return (this->count_ + 1) * plt_entry_size; } - - // Return the .rel.plt section data. - const Reloc_section* - rel_plt() const - { return this->rel_; } - - protected: - void - do_adjust_output_section(Output_section* os); - - // Write to a map file. - void - do_print_to_mapfile(Mapfile* mapfile) const - { mapfile->print_output_data(this, _("** PLT")); } - - private: - // The size of an entry in the PLT. - static const int plt_entry_size = 16; - - // The first entry in the PLT. - // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same - // procedure linkage table for both programs and shared objects." - static unsigned char first_plt_entry[plt_entry_size]; - - // Other entries in the PLT for an executable. - static unsigned char plt_entry[plt_entry_size]; - - // The reserved TLSDESC entry in the PLT for an executable. - static unsigned char tlsdesc_plt_entry[plt_entry_size]; - - // Set the final size. - void - set_final_data_size(); - - // Write out the PLT data. - void - do_write(Output_file*); - - // The reloc section. - Reloc_section* rel_; - // The .got section. - Output_data_got<64, false>* got_; - // The .got.plt section. - Output_data_space* got_plt_; - // The number of PLT entries. - unsigned int count_; - // Offset of the reserved TLSDESC_GOT entry when needed. - unsigned int tlsdesc_got_offset_; -}; - // Create the PLT section. The ordinary .got section is an argument, // since we need to refer to the start. We also create our own .got // section just for PLT entries. -Output_data_plt_x86_64::Output_data_plt_x86_64(Layout* layout, +Output_data_plt_x86_64::Output_data_plt_x86_64(Symbol_table* symtab, + 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_, true); + elfcpp::SHF_ALLOC, this->rel_, + ORDER_DYNAMIC_PLT_RELOCS, false); + + if (parameters->doing_static_link()) + { + // A statically linked executable will only have a .rela.plt + // section to hold R_X86_64_IRELATIVE relocs for STT_GNU_IFUNC + // symbols. The library will use these symbols to locate the + // IRELATIVE relocs at program startup time. + symtab->define_in_output_data("__rela_iplt_start", NULL, + Symbol_table::PREDEFINED, + this->rel_, 0, 0, elfcpp::STT_NOTYPE, + elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN, + 0, false, true); + symtab->define_in_output_data("__rela_iplt_end", NULL, + Symbol_table::PREDEFINED, + this->rel_, 0, 0, elfcpp::STT_NOTYPE, + elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN, + 0, true, true); + } } void @@ -638,15 +830,64 @@ Output_data_plt_x86_64::add_entry(Symbol* gsym) this->got_plt_->set_current_data_size(got_offset + 8); // Every PLT entry needs a reloc. - gsym->set_needs_dynsym_entry(); - this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_, - got_offset, 0); + if (gsym->type() == elfcpp::STT_GNU_IFUNC + && gsym->can_use_relative_reloc(false)) + this->rel_->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE, + this->got_plt_, got_offset, 0); + else + { + gsym->set_needs_dynsym_entry(); + this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_, + got_offset, 0); + } // Note that we don't need to save the symbol. The contents of the // PLT are independent of which symbols are used. The symbols only // appear in the relocations. } +// Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return +// the PLT offset. + +unsigned int +Output_data_plt_x86_64::add_local_ifunc_entry(Sized_relobj<64, false>* relobj, + unsigned int local_sym_index) +{ + unsigned int plt_offset = (this->count_ + 1) * plt_entry_size; + ++this->count_; + + section_offset_type got_offset = this->got_plt_->current_data_size(); + + // Every PLT entry needs a GOT entry which points back to the PLT + // entry. + this->got_plt_->set_current_data_size(got_offset + 8); + + // Every PLT entry needs a reloc. + this->rel_->add_symbolless_local_addend(relobj, local_sym_index, + elfcpp::R_X86_64_IRELATIVE, + this->got_plt_, got_offset, 0); + + return plt_offset; +} + +// 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_, + ORDER_DYNAMIC_PLT_RELOCS, 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() @@ -702,10 +943,10 @@ unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] = void Output_data_plt_x86_64::do_write(Output_file* of) { - const off_t off = this->offset(); + const off_t offset = this->offset(); const section_size_type oview_size = convert_to_section_size_type(this->data_size()); - unsigned char* const oview = of->get_output_view(off, oview_size); + unsigned char* const oview = of->get_output_view(offset, oview_size); const off_t got_file_offset = this->got_plt_->offset(); const section_size_type got_size = @@ -785,7 +1026,7 @@ Output_data_plt_x86_64::do_write(Output_file* of) gold_assert(static_cast(pov - oview) == oview_size); gold_assert(static_cast(got_pov - got_view) == got_size); - of->write_output_view(off, oview_size, oview); + of->write_output_view(offset, oview_size, oview); of->write_output_view(got_file_offset, got_size, got_view); } @@ -799,15 +1040,27 @@ Target_x86_64::make_plt_section(Symbol_table* symtab, Layout* layout) // Create the GOT sections first. this->got_section(symtab, layout); - this->plt_ = new Output_data_plt_x86_64(layout, this->got_, + this->plt_ = new Output_data_plt_x86_64(symtab, layout, this->got_, this->got_plt_); layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR), - this->plt_, false); + this->plt_, ORDER_PLT, false); + + // Make the sh_info field of .rela.plt point to .plt. + Output_section* rela_plt_os = this->plt_->rela_plt()->output_section(); + rela_plt_os->set_info_section(this->plt_->output_section()); } } +// 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 @@ -823,6 +1076,48 @@ Target_x86_64::make_plt_entry(Symbol_table* symtab, Layout* layout, this->plt_->add_entry(gsym); } +// Make a PLT entry for a local STT_GNU_IFUNC symbol. + +void +Target_x86_64::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout, + Sized_relobj<64, false>* relobj, + unsigned int local_sym_index) +{ + if (relobj->local_has_plt_offset(local_sym_index)) + return; + if (this->plt_ == NULL) + this->make_plt_section(symtab, layout); + unsigned int plt_offset = this->plt_->add_local_ifunc_entry(relobj, + local_sym_index); + relobj->set_local_plt_offset(local_sym_index, plt_offset); +} + +// Return the number of entries in the PLT. + +unsigned int +Target_x86_64::plt_entry_count() const +{ + if (this->plt_ == NULL) + return 0; + return this->plt_->entry_count(); +} + +// Return the offset of the first non-reserved PLT entry. + +unsigned int +Target_x86_64::first_plt_entry_offset() const +{ + return Output_data_plt_x86_64::first_plt_entry_offset(); +} + +// Return the size of each PLT entry. + +unsigned int +Target_x86_64::plt_entry_size() const +{ + return Output_data_plt_x86_64::get_plt_entry_size(); +} + // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. void @@ -836,6 +1131,7 @@ Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout) { 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, @@ -943,6 +1239,73 @@ Target_x86_64::optimize_tls_reloc(bool is_final, int r_type) } } +// Get the Reference_flags for a particular relocation. + +int +Target_x86_64::Scan::get_reference_flags(unsigned int r_type) +{ + switch (r_type) + { + case elfcpp::R_X86_64_NONE: + case elfcpp::R_X86_64_GNU_VTINHERIT: + case elfcpp::R_X86_64_GNU_VTENTRY: + case elfcpp::R_X86_64_GOTPC32: + case elfcpp::R_X86_64_GOTPC64: + // No symbol reference. + return 0; + + 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 Symbol::ABSOLUTE_REF; + + case elfcpp::R_X86_64_PC64: + case elfcpp::R_X86_64_PC32: + case elfcpp::R_X86_64_PC16: + case elfcpp::R_X86_64_PC8: + case elfcpp::R_X86_64_GOTOFF64: + return Symbol::RELATIVE_REF; + + case elfcpp::R_X86_64_PLT32: + case elfcpp::R_X86_64_PLTOFF64: + return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF; + + 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: + // Absolute in GOT. + return Symbol::ABSOLUTE_REF; + + 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 Symbol::TLS_REF; + + 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: + case elfcpp::R_X86_64_IRELATIVE: + case elfcpp::R_X86_64_TPOFF64: + case elfcpp::R_X86_64_DTPMOD64: + case elfcpp::R_X86_64_TLSDESC: + case elfcpp::R_X86_64_SIZE32: + case elfcpp::R_X86_64_SIZE64: + default: + // Not expected. We will give an error later. + return 0; + } +} + // Report an unsupported relocation against a local symbol. void @@ -966,17 +1329,28 @@ 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. + // These are the relocation types supported by glibc for x86_64 + // which should always work. case elfcpp::R_X86_64_RELATIVE: + case elfcpp::R_X86_64_IRELATIVE: 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_COPY: + return; + + // glibc supports these reloc types, but they can overflow. case elfcpp::R_X86_64_32: case elfcpp::R_X86_64_PC32: - case elfcpp::R_X86_64_COPY: + if (this->issued_non_pic_error_) + return; + gold_assert(parameters->options().output_is_position_independent()); + object->error(_("requires dynamic reloc which may overflow at runtime; " + "recompile with -fPIC")); + this->issued_non_pic_error_ = true; return; default: @@ -996,6 +1370,20 @@ Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type) } } +// Return whether we need to make a PLT entry for a relocation of the +// given type against a STT_GNU_IFUNC symbol. + +bool +Target_x86_64::Scan::reloc_needs_plt_for_ifunc(Sized_relobj<64, false>* object, + unsigned int r_type) +{ + int flags = Scan::get_reference_flags(r_type); + if (flags & Symbol::TLS_REF) + gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"), + object->name().c_str(), r_type); + return flags != 0; +} + // Scan a relocation for a local symbol. inline void @@ -1009,11 +1397,19 @@ Target_x86_64::Scan::local(Symbol_table* symtab, unsigned int r_type, const elfcpp::Sym<64, false>& lsym) { + // A local STT_GNU_IFUNC symbol may require a PLT entry. + if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC + && this->reloc_needs_plt_for_ifunc(object, r_type)) + { + unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info()); + target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym); + } + 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_GNU_VTINHERIT: + case elfcpp::R_X86_64_GNU_VTENTRY: break; case elfcpp::R_X86_64_64: @@ -1027,11 +1423,11 @@ Target_x86_64::Scan::local(Symbol_table* symtab, { unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info()); Reloc_section* rela_dyn = target->rela_dyn_section(layout); - rela_dyn->add_local_relative(object, r_sym, - elfcpp::R_X86_64_RELATIVE, - output_section, data_shndx, - reloc.get_r_offset(), - reloc.get_r_addend()); + rela_dyn->add_local_relative(object, r_sym, + elfcpp::R_X86_64_RELATIVE, + output_section, data_shndx, + reloc.get_r_offset(), + reloc.get_r_addend()); } break; @@ -1102,7 +1498,16 @@ Target_x86_64::Scan::local(Symbol_table* symtab, // The symbol requires a GOT entry. Output_data_got<64, false>* got = target->got_section(symtab, layout); unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info()); - if (got->add_local(object, r_sym, GOT_TYPE_STANDARD)) + + // For a STT_GNU_IFUNC symbol we want the PLT offset. That + // lets function pointers compare correctly with shared + // libraries. Otherwise we would need an IRELATIVE reloc. + bool is_new; + if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC) + is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD); + else + is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD); + if (is_new) { // If we are generating a shared object, we need to add a // dynamic relocation for this symbol's GOT entry. @@ -1111,9 +1516,13 @@ Target_x86_64::Scan::local(Symbol_table* symtab, Reloc_section* rela_dyn = target->rela_dyn_section(layout); // R_X86_64_RELATIVE assumes a 64-bit relocation. if (r_type != elfcpp::R_X86_64_GOT32) - rela_dyn->add_local_relative( - object, r_sym, elfcpp::R_X86_64_RELATIVE, got, - object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0); + { + unsigned int got_offset = + object->local_got_offset(r_sym, GOT_TYPE_STANDARD); + rela_dyn->add_local_relative(object, r_sym, + elfcpp::R_X86_64_RELATIVE, + got, got_offset, 0); + } else { this->check_non_pic(object, r_type); @@ -1134,6 +1543,7 @@ Target_x86_64::Scan::local(Symbol_table* symtab, case elfcpp::R_X86_64_GLOB_DAT: case elfcpp::R_X86_64_JUMP_SLOT: case elfcpp::R_X86_64_RELATIVE: + case elfcpp::R_X86_64_IRELATIVE: // These are outstanding tls relocs, which are unexpected when linking case elfcpp::R_X86_64_TPOFF64: case elfcpp::R_X86_64_DTPMOD64: @@ -1189,22 +1599,29 @@ Target_x86_64::Scan::local(Symbol_table* symtab, // 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); + // Generate a double GOT entry with an + // R_X86_64_TLSDESC reloc. The R_X86_64_TLSDESC reloc + // is resolved lazily, so the GOT entry needs to be in + // an area in .got.plt, not .got. Call got_section to + // make sure the section has been created. + target->got_section(symtab, layout); + Output_data_got<64, false>* got = target->got_tlsdesc_section(); 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(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); @@ -1276,6 +1693,77 @@ 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 @@ -1289,11 +1777,16 @@ Target_x86_64::Scan::global(Symbol_table* symtab, unsigned int r_type, Symbol* gsym) { + // A STT_GNU_IFUNC symbol may require a PLT entry. + if (gsym->type() == elfcpp::STT_GNU_IFUNC + && this->reloc_needs_plt_for_ifunc(object, r_type)) + target->make_plt_entry(symtab, layout, gsym); + 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_GNU_VTINHERIT: + case elfcpp::R_X86_64_GNU_VTENTRY: break; case elfcpp::R_X86_64_64: @@ -1314,21 +1807,41 @@ Target_x86_64::Scan::global(Symbol_table* symtab, gsym->set_needs_dynsym_value(); } // Make a dynamic relocation if necessary. - if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF)) + if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))) { if (gsym->may_need_copy_reloc()) { target->copy_reloc(symtab, layout, object, data_shndx, output_section, gsym, reloc); } + else if (r_type == elfcpp::R_X86_64_64 + && gsym->type() == elfcpp::STT_GNU_IFUNC + && gsym->can_use_relative_reloc(false) + && !gsym->is_from_dynobj() + && !gsym->is_undefined() + && !gsym->is_preemptible()) + { + // Use an IRELATIVE reloc for a locally defined + // STT_GNU_IFUNC symbol. This makes a function + // address in a PIE executable match the address in a + // shared library that it links against. + Reloc_section* rela_dyn = target->rela_dyn_section(layout); + unsigned int r_type = elfcpp::R_X86_64_IRELATIVE; + rela_dyn->add_symbolless_global_addend(gsym, r_type, + output_section, object, + data_shndx, + reloc.get_r_offset(), + reloc.get_r_addend()); + } else if (r_type == elfcpp::R_X86_64_64 && gsym->can_use_relative_reloc(false)) { Reloc_section* rela_dyn = target->rela_dyn_section(layout); - rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE, - output_section, object, - data_shndx, reloc.get_r_offset(), - reloc.get_r_addend()); + rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE, + output_section, object, + data_shndx, + reloc.get_r_offset(), + reloc.get_r_addend()); } else { @@ -1351,10 +1864,7 @@ Target_x86_64::Scan::global(Symbol_table* symtab, if (gsym->needs_plt_entry()) target->make_plt_entry(symtab, layout, gsym); // Make a dynamic relocation if necessary. - int flags = Symbol::NON_PIC_REF; - if (gsym->is_func()) - flags |= Symbol::FUNCTION_CALL; - if (gsym->needs_dynamic_reloc(flags)) + if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))) { if (gsym->may_need_copy_reloc()) { @@ -1382,23 +1892,49 @@ Target_x86_64::Scan::global(Symbol_table* symtab, // The symbol requires a GOT entry. Output_data_got<64, false>* got = target->got_section(symtab, layout); if (gsym->final_value_is_known()) - got->add_global(gsym, GOT_TYPE_STANDARD); + { + // For a STT_GNU_IFUNC symbol we want the PLT address. + if (gsym->type() == elfcpp::STT_GNU_IFUNC) + got->add_global_plt(gsym, GOT_TYPE_STANDARD); + else + got->add_global(gsym, GOT_TYPE_STANDARD); + } else { // If this symbol is not fully resolved, we need to add a // dynamic relocation for it. Reloc_section* rela_dyn = target->rela_dyn_section(layout); - if (gsym->is_from_dynobj() - || gsym->is_undefined() - || gsym->is_preemptible()) + if (gsym->is_from_dynobj() + || gsym->is_undefined() + || gsym->is_preemptible() + || (gsym->type() == elfcpp::STT_GNU_IFUNC + && parameters->options().output_is_position_independent())) got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn, elfcpp::R_X86_64_GLOB_DAT); else { - if (got->add_global(gsym, GOT_TYPE_STANDARD)) - rela_dyn->add_global_relative( - gsym, elfcpp::R_X86_64_RELATIVE, got, - gsym->got_offset(GOT_TYPE_STANDARD), 0); + // For a STT_GNU_IFUNC symbol we want to write the PLT + // offset into the GOT, so that function pointer + // comparisons work correctly. + bool is_new; + if (gsym->type() != elfcpp::STT_GNU_IFUNC) + is_new = got->add_global(gsym, GOT_TYPE_STANDARD); + else + { + is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD); + // Tell the dynamic linker to use the PLT address + // when resolving relocations. + if (gsym->is_from_dynobj() + && !parameters->options().shared()) + gsym->set_needs_dynsym_value(); + } + if (is_new) + { + unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD); + rela_dyn->add_global_relative(gsym, + elfcpp::R_X86_64_RELATIVE, + got, got_off, 0); + } } } // For GOTPLT64, we also need a PLT entry (but only if the @@ -1441,6 +1977,7 @@ Target_x86_64::Scan::global(Symbol_table* symtab, case elfcpp::R_X86_64_GLOB_DAT: case elfcpp::R_X86_64_JUMP_SLOT: case elfcpp::R_X86_64_RELATIVE: + case elfcpp::R_X86_64_IRELATIVE: // These are outstanding tls relocs, which are unexpected when linking case elfcpp::R_X86_64_TPOFF64: case elfcpp::R_X86_64_DTPMOD64: @@ -1496,11 +2033,15 @@ Target_x86_64::Scan::global(Symbol_table* symtab, // Create reserved PLT and GOT entries for the resolver. target->reserve_tlsdesc_entries(symtab, layout); - // Create a double GOT entry with an R_X86_64_TLSDESC reloc. - Output_data_got<64, false>* got - = target->got_section(symtab, layout); - got->add_global_pair_with_rela(gsym, GOT_TYPE_TLS_DESC, - target->rela_dyn_section(layout), + // Create a double GOT entry with an R_X86_64_TLSDESC + // reloc. The R_X86_64_TLSDESC reloc is resolved + // lazily, so the GOT entry needs to be in an area in + // .got.plt, not .got. Call got_section to make sure + // the section has been created. + target->got_section(symtab, layout); + Output_data_got<64, false>* got = target->got_tlsdesc_section(); + 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) @@ -1590,7 +2131,8 @@ Target_x86_64::gc_process_relocs(Symbol_table* symtab, } gold::gc_process_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA, - Target_x86_64::Scan>( + Target_x86_64::Scan, + Target_x86_64::Relocatable_size_for_reloc>( symtab, layout, this, @@ -1647,50 +2189,29 @@ void Target_x86_64::do_finalize_sections( Layout* layout, const Input_objects*, - Symbol_table*) + 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 - && this->got_plt_->output_section() != NULL) - odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_); - if (this->plt_ != NULL - && this->plt_->output_section() != NULL) - { - const Output_data* od = this->plt_->rel_plt(); - odyn->add_section_size(elfcpp::DT_PLTRELSZ, od); - odyn->add_section_address(elfcpp::DT_JMPREL, od); - odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_RELA); - if (this->plt_->has_tlsdesc_entry()) - { - unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset(); - unsigned int got_offset = this->plt_->get_tlsdesc_got_offset(); - this->got_->finalize_data_size(); - odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT, - this->plt_, plt_offset); - odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT, - this->got_, got_offset); - } - } - - if (this->rela_dyn_ != NULL - && this->rela_dyn_->output_section() != 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()) + && this->plt_->output_section() != NULL + && this->plt_->has_tlsdesc_entry()) { - // 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); } } @@ -1698,6 +2219,15 @@ Target_x86_64::do_finalize_sections( // 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. @@ -1732,20 +2262,28 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo, } } - // Pick the value to use for symbols defined in shared objects. + const Sized_relobj<64, false>* object = relinfo->object; + + // Pick the value to use for symbols defined in the PLT. Symbol_value<64> symval; if (gsym != NULL - && gsym->use_plt_offset(r_type == elfcpp::R_X86_64_PC64 - || r_type == elfcpp::R_X86_64_PC32 - || r_type == elfcpp::R_X86_64_PC16 - || r_type == elfcpp::R_X86_64_PC8)) + && gsym->use_plt_offset(Scan::get_reference_flags(r_type))) { symval.set_output_value(target->plt_section()->address() + gsym->plt_offset()); psymval = &symval; } + else if (gsym == NULL && psymval->is_ifunc_symbol()) + { + unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info()); + if (object->local_has_plt_offset(r_sym)) + { + symval.set_output_value(target->plt_section()->address() + + object->local_plt_offset(r_sym)); + psymval = &symval; + } + } - const Sized_relobj<64, false>* object = relinfo->object; const elfcpp::Elf_Xword addend = rela.get_r_addend(); // Get the GOT offset if needed. @@ -1783,8 +2321,8 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo, 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_GNU_VTINHERIT: + case elfcpp::R_X86_64_GNU_VTENTRY: break; case elfcpp::R_X86_64_64: @@ -1921,6 +2459,7 @@ Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo, case elfcpp::R_X86_64_GLOB_DAT: case elfcpp::R_X86_64_JUMP_SLOT: case elfcpp::R_X86_64_RELATIVE: + case elfcpp::R_X86_64_IRELATIVE: // These are outstanding tls relocs, which are unexpected when linking case elfcpp::R_X86_64_TPOFF64: case elfcpp::R_X86_64_DTPMOD64: @@ -1973,18 +2512,29 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, const Sized_relobj<64, false>* object = relinfo->object; const elfcpp::Elf_Xword addend = rela.get_r_addend(); + elfcpp::Shdr<64, false> data_shdr(relinfo->data_shdr); + bool is_executable = (data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0; 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 + tls::Tls_optimization optimized_type = Target_x86_64::optimize_tls_reloc(is_final, r_type); switch (r_type) { case elfcpp::R_X86_64_TLSGD: // Global-dynamic - this->saw_tls_block_reloc_ = true; + if (!is_executable && optimized_type == tls::TLSOPT_TO_LE) + { + // If this code sequence is used in a non-executable section, + // we will not optimize the R_X86_64_DTPOFF32/64 relocation, + // on the assumption that it's being used by itself in a debug + // section. Therefore, in the unlikely event that the code + // sequence appears in a non-executable section, we simply + // leave it unoptimized. + optimized_type = tls::TLSOPT_NONE; + } if (optimized_type == tls::TLSOPT_TO_LE) { gold_assert(tls_segment != NULL); @@ -2035,7 +2585,11 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, 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 (!is_executable && optimized_type == tls::TLSOPT_TO_LE) + { + // See above comment for R_X86_64_TLSGD. + optimized_type = tls::TLSOPT_NONE; + } if (optimized_type == tls::TLSOPT_TO_LE) { gold_assert(tls_segment != NULL); @@ -2049,18 +2603,27 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE ? GOT_TYPE_TLS_OFFSET : GOT_TYPE_TLS_DESC); - unsigned int got_offset; + unsigned int got_offset = 0; + if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC + && optimized_type == tls::TLSOPT_NONE) + { + // We created GOT entries in the .got.tlsdesc portion of + // the .got.plt section, but the offset stored in the + // symbol is the offset within .got.tlsdesc. + got_offset = (target->got_size() + + target->got_plt_section()->data_size()); + } if (gsym != NULL) { gold_assert(gsym->has_got_offset(got_type)); - got_offset = gsym->got_offset(got_type) - target->got_size(); + 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()); + got_offset += (object->local_got_offset(r_sym, got_type) + - target->got_size()); } if (optimized_type == tls::TLSOPT_TO_IE) { @@ -2089,7 +2652,11 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, break; case elfcpp::R_X86_64_TLSLD: // Local-dynamic - this->saw_tls_block_reloc_ = true; + if (!is_executable && optimized_type == tls::TLSOPT_TO_LE) + { + // See above comment for R_X86_64_TLSGD. + optimized_type = tls::TLSOPT_NONE; + } if (optimized_type == tls::TLSOPT_TO_LE) { gold_assert(tls_segment != NULL); @@ -2114,31 +2681,27 @@ Target_x86_64::Relocate::relocate_tls(const Relocate_info<64, false>* relinfo, break; case elfcpp::R_X86_64_DTPOFF32: - if (optimized_type == tls::TLSOPT_TO_LE) - { - // This relocation type is used in debugging information. - // In that case we need to not optimize the value. If we - // haven't seen a TLSLD reloc, then we assume we should not - // optimize this reloc. - if (this->saw_tls_block_reloc_) - { - gold_assert(tls_segment != NULL); - value -= tls_segment->memsz(); - } - } + // This relocation type is used in debugging information. + // In that case we need to not optimize the value. If the + // section is not executable, then we assume we should not + // optimize this reloc. See comments above for R_X86_64_TLSGD, + // R_X86_64_GOTPC32_TLSDESC, R_X86_64_TLSDESC_CALL, and + // R_X86_64_TLSLD. + if (optimized_type == tls::TLSOPT_TO_LE && is_executable) + { + gold_assert(tls_segment != NULL); + value -= tls_segment->memsz(); + } Relocate_functions<64, false>::rela32(view, value, addend); break; case elfcpp::R_X86_64_DTPOFF64: - if (optimized_type == tls::TLSOPT_TO_LE) - { - // See R_X86_64_DTPOFF32, just above, for why we test this. - if (this->saw_tls_block_reloc_) - { - gold_assert(tls_segment != NULL); - value -= tls_segment->memsz(); - } - } + // See R_X86_64_DTPOFF32, just above, for why we check for is_executable. + if (optimized_type == tls::TLSOPT_TO_LE && is_executable) + { + gold_assert(tls_segment != NULL); + value -= tls_segment->memsz(); + } Relocate_functions<64, false>::rela64(view, value, addend); break; @@ -2462,8 +3025,8 @@ Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc( 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_GNU_VTINHERIT: + case elfcpp::R_X86_64_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: @@ -2505,6 +3068,7 @@ Target_x86_64::Relocatable_size_for_reloc::get_size_for_reloc( case elfcpp::R_X86_64_GLOB_DAT: case elfcpp::R_X86_64_JUMP_SLOT: case elfcpp::R_X86_64_RELATIVE: + case elfcpp::R_X86_64_IRELATIVE: // These are outstanding tls relocs, which are unexpected when linking case elfcpp::R_X86_64_TPOFF64: case elfcpp::R_X86_64_DTPMOD64: @@ -2664,8 +3228,27 @@ 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(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 +// compiled with -fsplit-stack. The function calls non-split-stack // code. We have to change the function so that it always ensures // that it has enough stack space to run some random function. @@ -2692,7 +3275,11 @@ Target_x86_64::do_calls_non_split(Relobj* object, unsigned int shndx, this->set_view_to_nop(view, view_size, fnoffset + 1, 8); } // lea NN(%rsp),%r10 - else if (this->match_view(view, view_size, fnoffset, "\x4c\x8d\x94\x24", 4) + // 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