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Diffstat (limited to 'binutils-2.25/gold/symtab.h')
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diff --git a/binutils-2.25/gold/symtab.h b/binutils-2.25/gold/symtab.h new file mode 100644 index 00000000..9299ea8a --- /dev/null +++ b/binutils-2.25/gold/symtab.h @@ -0,0 +1,1927 @@ +// symtab.h -- the gold symbol table -*- C++ -*- + +// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. +// Written by Ian Lance Taylor <iant@google.com>. + +// This file is part of gold. + +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 3 of the License, or +// (at your option) any later version. + +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, +// MA 02110-1301, USA. + +// Symbol_table +// The symbol table. + +#ifndef GOLD_SYMTAB_H +#define GOLD_SYMTAB_H + +#include <string> +#include <utility> +#include <vector> + +#include "elfcpp.h" +#include "parameters.h" +#include "stringpool.h" +#include "object.h" + +namespace gold +{ + +class Mapfile; +class Object; +class Relobj; +template<int size, bool big_endian> +class Sized_relobj_file; +template<int size, bool big_endian> +class Sized_pluginobj; +class Dynobj; +template<int size, bool big_endian> +class Sized_dynobj; +template<int size, bool big_endian> +class Sized_incrobj; +class Versions; +class Version_script_info; +class Input_objects; +class Output_data; +class Output_section; +class Output_segment; +class Output_file; +class Output_symtab_xindex; +class Garbage_collection; +class Icf; + +// The base class of an entry in the symbol table. The symbol table +// can have a lot of entries, so we don't want this class too big. +// Size dependent fields can be found in the template class +// Sized_symbol. Targets may support their own derived classes. + +class Symbol +{ + public: + // Because we want the class to be small, we don't use any virtual + // functions. But because symbols can be defined in different + // places, we need to classify them. This enum is the different + // sources of symbols we support. + enum Source + { + // Symbol defined in a relocatable or dynamic input file--this is + // the most common case. + FROM_OBJECT, + // Symbol defined in an Output_data, a special section created by + // the target. + IN_OUTPUT_DATA, + // Symbol defined in an Output_segment, with no associated + // section. + IN_OUTPUT_SEGMENT, + // Symbol value is constant. + IS_CONSTANT, + // Symbol is undefined. + IS_UNDEFINED + }; + + // When the source is IN_OUTPUT_SEGMENT, we need to describe what + // the offset means. + enum Segment_offset_base + { + // From the start of the segment. + SEGMENT_START, + // From the end of the segment. + SEGMENT_END, + // From the filesz of the segment--i.e., after the loaded bytes + // but before the bytes which are allocated but zeroed. + SEGMENT_BSS + }; + + // Return the symbol name. + const char* + name() const + { return this->name_; } + + // Return the (ANSI) demangled version of the name, if + // parameters.demangle() is true. Otherwise, return the name. This + // is intended to be used only for logging errors, so it's not + // super-efficient. + std::string + demangled_name() const; + + // Return the symbol version. This will return NULL for an + // unversioned symbol. + const char* + version() const + { return this->version_; } + + void + clear_version() + { this->version_ = NULL; } + + // Return whether this version is the default for this symbol name + // (eg, "foo@@V2" is a default version; "foo@V1" is not). Only + // meaningful for versioned symbols. + bool + is_default() const + { + gold_assert(this->version_ != NULL); + return this->is_def_; + } + + // Set that this version is the default for this symbol name. + void + set_is_default() + { this->is_def_ = true; } + + // Return the symbol's name as name@version (or name@@version). + std::string + versioned_name() const; + + // Return the symbol source. + Source + source() const + { return this->source_; } + + // Return the object with which this symbol is associated. + Object* + object() const + { + gold_assert(this->source_ == FROM_OBJECT); + return this->u_.from_object.object; + } + + // Return the index of the section in the input relocatable or + // dynamic object file. + unsigned int + shndx(bool* is_ordinary) const + { + gold_assert(this->source_ == FROM_OBJECT); + *is_ordinary = this->is_ordinary_shndx_; + return this->u_.from_object.shndx; + } + + // Return the output data section with which this symbol is + // associated, if the symbol was specially defined with respect to + // an output data section. + Output_data* + output_data() const + { + gold_assert(this->source_ == IN_OUTPUT_DATA); + return this->u_.in_output_data.output_data; + } + + // If this symbol was defined with respect to an output data + // section, return whether the value is an offset from end. + bool + offset_is_from_end() const + { + gold_assert(this->source_ == IN_OUTPUT_DATA); + return this->u_.in_output_data.offset_is_from_end; + } + + // Return the output segment with which this symbol is associated, + // if the symbol was specially defined with respect to an output + // segment. + Output_segment* + output_segment() const + { + gold_assert(this->source_ == IN_OUTPUT_SEGMENT); + return this->u_.in_output_segment.output_segment; + } + + // If this symbol was defined with respect to an output segment, + // return the offset base. + Segment_offset_base + offset_base() const + { + gold_assert(this->source_ == IN_OUTPUT_SEGMENT); + return this->u_.in_output_segment.offset_base; + } + + // Return the symbol binding. + elfcpp::STB + binding() const + { return this->binding_; } + + // Return the symbol type. + elfcpp::STT + type() const + { return this->type_; } + + // Return true for function symbol. + bool + is_func() const + { + return (this->type_ == elfcpp::STT_FUNC + || this->type_ == elfcpp::STT_GNU_IFUNC); + } + + // Return the symbol visibility. + elfcpp::STV + visibility() const + { return this->visibility_; } + + // Set the visibility. + void + set_visibility(elfcpp::STV visibility) + { this->visibility_ = visibility; } + + // Override symbol visibility. + void + override_visibility(elfcpp::STV); + + // Set whether the symbol was originally a weak undef or a regular undef + // when resolved by a dynamic def. + inline void + set_undef_binding(elfcpp::STB bind) + { + if (!this->undef_binding_set_ || this->undef_binding_weak_) + { + this->undef_binding_weak_ = bind == elfcpp::STB_WEAK; + this->undef_binding_set_ = true; + } + } + + // Return TRUE if a weak undef was resolved by a dynamic def. + inline bool + is_undef_binding_weak() const + { return this->undef_binding_weak_; } + + // Return the non-visibility part of the st_other field. + unsigned char + nonvis() const + { return this->nonvis_; } + + // Return whether this symbol is a forwarder. This will never be + // true of a symbol found in the hash table, but may be true of + // symbol pointers attached to object files. + bool + is_forwarder() const + { return this->is_forwarder_; } + + // Mark this symbol as a forwarder. + void + set_forwarder() + { this->is_forwarder_ = true; } + + // Return whether this symbol has an alias in the weak aliases table + // in Symbol_table. + bool + has_alias() const + { return this->has_alias_; } + + // Mark this symbol as having an alias. + void + set_has_alias() + { this->has_alias_ = true; } + + // Return whether this symbol needs an entry in the dynamic symbol + // table. + bool + needs_dynsym_entry() const + { + return (this->needs_dynsym_entry_ + || (this->in_reg() + && this->in_dyn() + && this->is_externally_visible())); + } + + // Mark this symbol as needing an entry in the dynamic symbol table. + void + set_needs_dynsym_entry() + { this->needs_dynsym_entry_ = true; } + + // Return whether this symbol should be added to the dynamic symbol + // table. + bool + should_add_dynsym_entry(Symbol_table*) const; + + // Return whether this symbol has been seen in a regular object. + bool + in_reg() const + { return this->in_reg_; } + + // Mark this symbol as having been seen in a regular object. + void + set_in_reg() + { this->in_reg_ = true; } + + // Return whether this symbol has been seen in a dynamic object. + bool + in_dyn() const + { return this->in_dyn_; } + + // Mark this symbol as having been seen in a dynamic object. + void + set_in_dyn() + { this->in_dyn_ = true; } + + // Return whether this symbol has been seen in a real ELF object. + // (IN_REG will return TRUE if the symbol has been seen in either + // a real ELF object or an object claimed by a plugin.) + bool + in_real_elf() const + { return this->in_real_elf_; } + + // Mark this symbol as having been seen in a real ELF object. + void + set_in_real_elf() + { this->in_real_elf_ = true; } + + // Return whether this symbol was defined in a section that was + // discarded from the link. This is used to control some error + // reporting. + bool + is_defined_in_discarded_section() const + { return this->is_defined_in_discarded_section_; } + + // Mark this symbol as having been defined in a discarded section. + void + set_is_defined_in_discarded_section() + { this->is_defined_in_discarded_section_ = true; } + + // Return the index of this symbol in the output file symbol table. + // A value of -1U means that this symbol is not going into the + // output file. This starts out as zero, and is set to a non-zero + // value by Symbol_table::finalize. It is an error to ask for the + // symbol table index before it has been set. + unsigned int + symtab_index() const + { + gold_assert(this->symtab_index_ != 0); + return this->symtab_index_; + } + + // Set the index of the symbol in the output file symbol table. + void + set_symtab_index(unsigned int index) + { + gold_assert(index != 0); + this->symtab_index_ = index; + } + + // Return whether this symbol already has an index in the output + // file symbol table. + bool + has_symtab_index() const + { return this->symtab_index_ != 0; } + + // Return the index of this symbol in the dynamic symbol table. A + // value of -1U means that this symbol is not going into the dynamic + // symbol table. This starts out as zero, and is set to a non-zero + // during Layout::finalize. It is an error to ask for the dynamic + // symbol table index before it has been set. + unsigned int + dynsym_index() const + { + gold_assert(this->dynsym_index_ != 0); + return this->dynsym_index_; + } + + // Set the index of the symbol in the dynamic symbol table. + void + set_dynsym_index(unsigned int index) + { + gold_assert(index != 0); + this->dynsym_index_ = index; + } + + // Return whether this symbol already has an index in the dynamic + // symbol table. + bool + has_dynsym_index() const + { return this->dynsym_index_ != 0; } + + // Return whether this symbol has an entry in the GOT section. + // For a TLS symbol, this GOT entry will hold its tp-relative offset. + bool + has_got_offset(unsigned int got_type) const + { return this->got_offsets_.get_offset(got_type) != -1U; } + + // Return the offset into the GOT section of this symbol. + unsigned int + got_offset(unsigned int got_type) const + { + unsigned int got_offset = this->got_offsets_.get_offset(got_type); + gold_assert(got_offset != -1U); + return got_offset; + } + + // Set the GOT offset of this symbol. + void + set_got_offset(unsigned int got_type, unsigned int got_offset) + { this->got_offsets_.set_offset(got_type, got_offset); } + + // Return the GOT offset list. + const Got_offset_list* + got_offset_list() const + { return this->got_offsets_.get_list(); } + + // Return whether this symbol has an entry in the PLT section. + bool + has_plt_offset() const + { return this->plt_offset_ != -1U; } + + // Return the offset into the PLT section of this symbol. + unsigned int + plt_offset() const + { + gold_assert(this->has_plt_offset()); + return this->plt_offset_; + } + + // Set the PLT offset of this symbol. + void + set_plt_offset(unsigned int plt_offset) + { + gold_assert(plt_offset != -1U); + this->plt_offset_ = plt_offset; + } + + // Return whether this dynamic symbol needs a special value in the + // dynamic symbol table. + bool + needs_dynsym_value() const + { return this->needs_dynsym_value_; } + + // Set that this dynamic symbol needs a special value in the dynamic + // symbol table. + void + set_needs_dynsym_value() + { + gold_assert(this->object()->is_dynamic()); + this->needs_dynsym_value_ = true; + } + + // Return true if the final value of this symbol is known at link + // time. + bool + final_value_is_known() const; + + // Return true if SHNDX represents a common symbol. This depends on + // the target. + static bool + is_common_shndx(unsigned int shndx); + + // Return whether this is a defined symbol (not undefined or + // common). + bool + is_defined() const + { + bool is_ordinary; + if (this->source_ != FROM_OBJECT) + return this->source_ != IS_UNDEFINED; + unsigned int shndx = this->shndx(&is_ordinary); + return (is_ordinary + ? shndx != elfcpp::SHN_UNDEF + : !Symbol::is_common_shndx(shndx)); + } + + // Return true if this symbol is from a dynamic object. + bool + is_from_dynobj() const + { + return this->source_ == FROM_OBJECT && this->object()->is_dynamic(); + } + + // Return whether this is a placeholder symbol from a plugin object. + bool + is_placeholder() const + { + return this->source_ == FROM_OBJECT && this->object()->pluginobj() != NULL; + } + + // Return whether this is an undefined symbol. + bool + is_undefined() const + { + bool is_ordinary; + return ((this->source_ == FROM_OBJECT + && this->shndx(&is_ordinary) == elfcpp::SHN_UNDEF + && is_ordinary) + || this->source_ == IS_UNDEFINED); + } + + // Return whether this is a weak undefined symbol. + bool + is_weak_undefined() const + { return this->is_undefined() && this->binding() == elfcpp::STB_WEAK; } + + // Return whether this is an absolute symbol. + bool + is_absolute() const + { + bool is_ordinary; + return ((this->source_ == FROM_OBJECT + && this->shndx(&is_ordinary) == elfcpp::SHN_ABS + && !is_ordinary) + || this->source_ == IS_CONSTANT); + } + + // Return whether this is a common symbol. + bool + is_common() const + { + if (this->source_ != FROM_OBJECT) + return false; + if (this->type_ == elfcpp::STT_COMMON) + return true; + bool is_ordinary; + unsigned int shndx = this->shndx(&is_ordinary); + return !is_ordinary && Symbol::is_common_shndx(shndx); + } + + // Return whether this symbol can be seen outside this object. + bool + is_externally_visible() const + { + return ((this->visibility_ == elfcpp::STV_DEFAULT + || this->visibility_ == elfcpp::STV_PROTECTED) + && !this->is_forced_local_); + } + + // Return true if this symbol can be preempted by a definition in + // another link unit. + bool + is_preemptible() const + { + // It doesn't make sense to ask whether a symbol defined in + // another object is preemptible. + gold_assert(!this->is_from_dynobj()); + + // It doesn't make sense to ask whether an undefined symbol + // is preemptible. + gold_assert(!this->is_undefined()); + + // If a symbol does not have default visibility, it can not be + // seen outside this link unit and therefore is not preemptible. + if (this->visibility_ != elfcpp::STV_DEFAULT) + return false; + + // If this symbol has been forced to be a local symbol by a + // version script, then it is not visible outside this link unit + // and is not preemptible. + if (this->is_forced_local_) + return false; + + // If we are not producing a shared library, then nothing is + // preemptible. + if (!parameters->options().shared()) + return false; + + // If the user used -Bsymbolic, then nothing is preemptible. + if (parameters->options().Bsymbolic()) + return false; + + // If the user used -Bsymbolic-functions, then functions are not + // preemptible. We explicitly check for not being STT_OBJECT, + // rather than for being STT_FUNC, because that is what the GNU + // linker does. + if (this->type() != elfcpp::STT_OBJECT + && parameters->options().Bsymbolic_functions()) + return false; + + // Otherwise the symbol is preemptible. + return true; + } + + // Return true if this symbol is a function that needs a PLT entry. + bool + needs_plt_entry() const + { + // An undefined symbol from an executable does not need a PLT entry. + if (this->is_undefined() && !parameters->options().shared()) + return false; + + // An STT_GNU_IFUNC symbol always needs a PLT entry, even when + // doing a static link. + if (this->type() == elfcpp::STT_GNU_IFUNC) + return true; + + // We only need a PLT entry for a function. + if (!this->is_func()) + return false; + + // If we're doing a static link or a -pie link, we don't create + // PLT entries. + if (parameters->doing_static_link() + || parameters->options().pie()) + return false; + + // We need a PLT entry if the function is defined in a dynamic + // object, or is undefined when building a shared object, or if it + // is subject to pre-emption. + return (this->is_from_dynobj() + || this->is_undefined() + || this->is_preemptible()); + } + + // When determining whether a reference to a symbol needs a dynamic + // relocation, we need to know several things about the reference. + // These flags may be or'ed together. 0 means that the symbol + // isn't referenced at all. + enum Reference_flags + { + // A reference to the symbol's absolute address. This includes + // references that cause an absolute address to be stored in the GOT. + ABSOLUTE_REF = 1, + // A reference that calculates the offset of the symbol from some + // anchor point, such as the PC or GOT. + RELATIVE_REF = 2, + // A TLS-related reference. + TLS_REF = 4, + // A reference that can always be treated as a function call. + FUNCTION_CALL = 8 + }; + + // Given a direct absolute or pc-relative static relocation against + // the global symbol, this function returns whether a dynamic relocation + // is needed. + + bool + needs_dynamic_reloc(int flags) const + { + // No dynamic relocations in a static link! + if (parameters->doing_static_link()) + return false; + + // A reference to an undefined symbol from an executable should be + // statically resolved to 0, and does not need a dynamic relocation. + // This matches gnu ld behavior. + if (this->is_undefined() && !parameters->options().shared()) + return false; + + // A reference to an absolute symbol does not need a dynamic relocation. + if (this->is_absolute()) + return false; + + // An absolute reference within a position-independent output file + // will need a dynamic relocation. + if ((flags & ABSOLUTE_REF) + && parameters->options().output_is_position_independent()) + return true; + + // A function call that can branch to a local PLT entry does not need + // a dynamic relocation. + if ((flags & FUNCTION_CALL) && this->has_plt_offset()) + return false; + + // A reference to any PLT entry in a non-position-independent executable + // does not need a dynamic relocation. + if (!parameters->options().output_is_position_independent() + && this->has_plt_offset()) + return false; + + // A reference to a symbol defined in a dynamic object or to a + // symbol that is preemptible will need a dynamic relocation. + if (this->is_from_dynobj() + || this->is_undefined() + || this->is_preemptible()) + return true; + + // For all other cases, return FALSE. + return false; + } + + // Whether we should use the PLT offset associated with a symbol for + // a relocation. FLAGS is a set of Reference_flags. + + bool + use_plt_offset(int flags) const + { + // If the symbol doesn't have a PLT offset, then naturally we + // don't want to use it. + if (!this->has_plt_offset()) + return false; + + // For a STT_GNU_IFUNC symbol we always have to use the PLT entry. + if (this->type() == elfcpp::STT_GNU_IFUNC) + return true; + + // If we are going to generate a dynamic relocation, then we will + // wind up using that, so no need to use the PLT entry. + if (this->needs_dynamic_reloc(flags)) + return false; + + // If the symbol is from a dynamic object, we need to use the PLT + // entry. + if (this->is_from_dynobj()) + return true; + + // If we are generating a shared object, and this symbol is + // undefined or preemptible, we need to use the PLT entry. + if (parameters->options().shared() + && (this->is_undefined() || this->is_preemptible())) + return true; + + // If this is a call to a weak undefined symbol, we need to use + // the PLT entry; the symbol may be defined by a library loaded + // at runtime. + if ((flags & FUNCTION_CALL) && this->is_weak_undefined()) + return true; + + // Otherwise we can use the regular definition. + return false; + } + + // Given a direct absolute static relocation against + // the global symbol, where a dynamic relocation is needed, this + // function returns whether a relative dynamic relocation can be used. + // The caller must determine separately whether the static relocation + // is compatible with a relative relocation. + + bool + can_use_relative_reloc(bool is_function_call) const + { + // A function call that can branch to a local PLT entry can + // use a RELATIVE relocation. + if (is_function_call && this->has_plt_offset()) + return true; + + // A reference to a symbol defined in a dynamic object or to a + // symbol that is preemptible can not use a RELATIVE relocation. + if (this->is_from_dynobj() + || this->is_undefined() + || this->is_preemptible()) + return false; + + // For all other cases, return TRUE. + return true; + } + + // Return the output section where this symbol is defined. Return + // NULL if the symbol has an absolute value. + Output_section* + output_section() const; + + // Set the symbol's output section. This is used for symbols + // defined in scripts. This should only be called after the symbol + // table has been finalized. + void + set_output_section(Output_section*); + + // Return whether there should be a warning for references to this + // symbol. + bool + has_warning() const + { return this->has_warning_; } + + // Mark this symbol as having a warning. + void + set_has_warning() + { this->has_warning_ = true; } + + // Return whether this symbol is defined by a COPY reloc from a + // dynamic object. + bool + is_copied_from_dynobj() const + { return this->is_copied_from_dynobj_; } + + // Mark this symbol as defined by a COPY reloc. + void + set_is_copied_from_dynobj() + { this->is_copied_from_dynobj_ = true; } + + // Return whether this symbol is forced to visibility STB_LOCAL + // by a "local:" entry in a version script. + bool + is_forced_local() const + { return this->is_forced_local_; } + + // Mark this symbol as forced to STB_LOCAL visibility. + void + set_is_forced_local() + { this->is_forced_local_ = true; } + + // Return true if this 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() const + { + return (!parameters->options().output_is_position_independent() + && parameters->options().copyreloc() + && this->is_from_dynobj() + && !this->is_func()); + } + + // Return true if this symbol was predefined by the linker. + bool + is_predefined() const + { return this->is_predefined_; } + + // Return true if this is a C++ vtable symbol. + bool + is_cxx_vtable() const + { return is_prefix_of("_ZTV", this->name_); } + + protected: + // Instances of this class should always be created at a specific + // size. + Symbol() + { memset(this, 0, sizeof *this); } + + // Initialize the general fields. + void + init_fields(const char* name, const char* version, + elfcpp::STT type, elfcpp::STB binding, + elfcpp::STV visibility, unsigned char nonvis); + + // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the + // section index, IS_ORDINARY is whether it is a normal section + // index rather than a special code. + template<int size, bool big_endian> + void + init_base_object(const char* name, const char* version, Object* object, + const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx, + bool is_ordinary); + + // Initialize fields for an Output_data. + void + init_base_output_data(const char* name, const char* version, Output_data*, + elfcpp::STT, elfcpp::STB, elfcpp::STV, + unsigned char nonvis, bool offset_is_from_end, + bool is_predefined); + + // Initialize fields for an Output_segment. + void + init_base_output_segment(const char* name, const char* version, + Output_segment* os, elfcpp::STT type, + elfcpp::STB binding, elfcpp::STV visibility, + unsigned char nonvis, + Segment_offset_base offset_base, + bool is_predefined); + + // Initialize fields for a constant. + void + init_base_constant(const char* name, const char* version, elfcpp::STT type, + elfcpp::STB binding, elfcpp::STV visibility, + unsigned char nonvis, bool is_predefined); + + // Initialize fields for an undefined symbol. + void + init_base_undefined(const char* name, const char* version, elfcpp::STT type, + elfcpp::STB binding, elfcpp::STV visibility, + unsigned char nonvis); + + // Override existing symbol. + template<int size, bool big_endian> + void + override_base(const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx, + bool is_ordinary, Object* object, const char* version); + + // Override existing symbol with a special symbol. + void + override_base_with_special(const Symbol* from); + + // Override symbol version. + void + override_version(const char* version); + + // Allocate a common symbol by giving it a location in the output + // file. + void + allocate_base_common(Output_data*); + + private: + Symbol(const Symbol&); + Symbol& operator=(const Symbol&); + + // Symbol name (expected to point into a Stringpool). + const char* name_; + // Symbol version (expected to point into a Stringpool). This may + // be NULL. + const char* version_; + + union + { + // This struct is used if SOURCE_ == FROM_OBJECT. + struct + { + // Object in which symbol is defined, or in which it was first + // seen. + Object* object; + // Section number in object_ in which symbol is defined. + unsigned int shndx; + } from_object; + + // This struct is used if SOURCE_ == IN_OUTPUT_DATA. + struct + { + // Output_data in which symbol is defined. Before + // Layout::finalize the symbol's value is an offset within the + // Output_data. + Output_data* output_data; + // True if the offset is from the end, false if the offset is + // from the beginning. + bool offset_is_from_end; + } in_output_data; + + // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT. + struct + { + // Output_segment in which the symbol is defined. Before + // Layout::finalize the symbol's value is an offset. + Output_segment* output_segment; + // The base to use for the offset before Layout::finalize. + Segment_offset_base offset_base; + } in_output_segment; + } u_; + + // The index of this symbol in the output file. If the symbol is + // not going into the output file, this value is -1U. This field + // starts as always holding zero. It is set to a non-zero value by + // Symbol_table::finalize. + unsigned int symtab_index_; + + // The index of this symbol in the dynamic symbol table. If the + // symbol is not going into the dynamic symbol table, this value is + // -1U. This field starts as always holding zero. It is set to a + // non-zero value during Layout::finalize. + unsigned int dynsym_index_; + + // The GOT section entries for this symbol. A symbol may have more + // than one GOT offset (e.g., when mixing modules compiled with two + // different TLS models), but will usually have at most one. + Got_offset_list got_offsets_; + + // If this symbol has an entry in the PLT section, then this is the + // offset from the start of the PLT section. This is -1U if there + // is no PLT entry. + unsigned int plt_offset_; + + // Symbol type (bits 0 to 3). + elfcpp::STT type_ : 4; + // Symbol binding (bits 4 to 7). + elfcpp::STB binding_ : 4; + // Symbol visibility (bits 8 to 9). + elfcpp::STV visibility_ : 2; + // Rest of symbol st_other field (bits 10 to 15). + unsigned int nonvis_ : 6; + // The type of symbol (bits 16 to 18). + Source source_ : 3; + // True if this is the default version of the symbol (bit 19). + bool is_def_ : 1; + // True if this symbol really forwards to another symbol. This is + // used when we discover after the fact that two different entries + // in the hash table really refer to the same symbol. This will + // never be set for a symbol found in the hash table, but may be set + // for a symbol found in the list of symbols attached to an Object. + // It forwards to the symbol found in the forwarders_ map of + // Symbol_table (bit 20). + bool is_forwarder_ : 1; + // True if the symbol has an alias in the weak_aliases table in + // Symbol_table (bit 21). + bool has_alias_ : 1; + // True if this symbol needs to be in the dynamic symbol table (bit + // 22). + bool needs_dynsym_entry_ : 1; + // True if we've seen this symbol in a regular object (bit 23). + bool in_reg_ : 1; + // True if we've seen this symbol in a dynamic object (bit 24). + bool in_dyn_ : 1; + // True if this is a dynamic symbol which needs a special value in + // the dynamic symbol table (bit 25). + bool needs_dynsym_value_ : 1; + // True if there is a warning for this symbol (bit 26). + bool has_warning_ : 1; + // True if we are using a COPY reloc for this symbol, so that the + // real definition lives in a dynamic object (bit 27). + bool is_copied_from_dynobj_ : 1; + // True if this symbol was forced to local visibility by a version + // script (bit 28). + bool is_forced_local_ : 1; + // True if the field u_.from_object.shndx is an ordinary section + // index, not one of the special codes from SHN_LORESERVE to + // SHN_HIRESERVE (bit 29). + bool is_ordinary_shndx_ : 1; + // True if we've seen this symbol in a "real" ELF object (bit 30). + // If the symbol has been seen in a relocatable, non-IR, object file, + // it's known to be referenced from outside the IR. A reference from + // a dynamic object doesn't count as a "real" ELF, and we'll simply + // mark the symbol as "visible" from outside the IR. The compiler + // can use this distinction to guide its handling of COMDAT symbols. + bool in_real_elf_ : 1; + // True if this symbol is defined in a section which was discarded + // (bit 31). + bool is_defined_in_discarded_section_ : 1; + // True if UNDEF_BINDING_WEAK_ has been set (bit 32). + bool undef_binding_set_ : 1; + // True if this symbol was a weak undef resolved by a dynamic def + // (bit 33). + bool undef_binding_weak_ : 1; + // True if this symbol is a predefined linker symbol (bit 34). + bool is_predefined_ : 1; +}; + +// The parts of a symbol which are size specific. Using a template +// derived class like this helps us use less space on a 32-bit system. + +template<int size> +class Sized_symbol : public Symbol +{ + public: + typedef typename elfcpp::Elf_types<size>::Elf_Addr Value_type; + typedef typename elfcpp::Elf_types<size>::Elf_WXword Size_type; + + Sized_symbol() + { } + + // Initialize fields from an ELF symbol in OBJECT. ST_SHNDX is the + // section index, IS_ORDINARY is whether it is a normal section + // index rather than a special code. + template<bool big_endian> + void + init_object(const char* name, const char* version, Object* object, + const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx, + bool is_ordinary); + + // Initialize fields for an Output_data. + void + init_output_data(const char* name, const char* version, Output_data*, + Value_type value, Size_type symsize, elfcpp::STT, + elfcpp::STB, elfcpp::STV, unsigned char nonvis, + bool offset_is_from_end, bool is_predefined); + + // Initialize fields for an Output_segment. + void + init_output_segment(const char* name, const char* version, Output_segment*, + Value_type value, Size_type symsize, elfcpp::STT, + elfcpp::STB, elfcpp::STV, unsigned char nonvis, + Segment_offset_base offset_base, bool is_predefined); + + // Initialize fields for a constant. + void + init_constant(const char* name, const char* version, Value_type value, + Size_type symsize, elfcpp::STT, elfcpp::STB, elfcpp::STV, + unsigned char nonvis, bool is_predefined); + + // Initialize fields for an undefined symbol. + void + init_undefined(const char* name, const char* version, elfcpp::STT, + elfcpp::STB, elfcpp::STV, unsigned char nonvis); + + // Override existing symbol. + template<bool big_endian> + void + override(const elfcpp::Sym<size, big_endian>&, unsigned int st_shndx, + bool is_ordinary, Object* object, const char* version); + + // Override existing symbol with a special symbol. + void + override_with_special(const Sized_symbol<size>*); + + // Return the symbol's value. + Value_type + value() const + { return this->value_; } + + // Return the symbol's size (we can't call this 'size' because that + // is a template parameter). + Size_type + symsize() const + { return this->symsize_; } + + // Set the symbol size. This is used when resolving common symbols. + void + set_symsize(Size_type symsize) + { this->symsize_ = symsize; } + + // Set the symbol value. This is called when we store the final + // values of the symbols into the symbol table. + void + set_value(Value_type value) + { this->value_ = value; } + + // Allocate a common symbol by giving it a location in the output + // file. + void + allocate_common(Output_data*, Value_type value); + + private: + Sized_symbol(const Sized_symbol&); + Sized_symbol& operator=(const Sized_symbol&); + + // Symbol value. Before Layout::finalize this is the offset in the + // input section. This is set to the final value during + // Layout::finalize. + Value_type value_; + // Symbol size. + Size_type symsize_; +}; + +// A struct describing a symbol defined by the linker, where the value +// of the symbol is defined based on an output section. This is used +// for symbols defined by the linker, like "_init_array_start". + +struct Define_symbol_in_section +{ + // The symbol name. + const char* name; + // The name of the output section with which this symbol should be + // associated. If there is no output section with that name, the + // symbol will be defined as zero. + const char* output_section; + // The offset of the symbol within the output section. This is an + // offset from the start of the output section, unless start_at_end + // is true, in which case this is an offset from the end of the + // output section. + uint64_t value; + // The size of the symbol. + uint64_t size; + // The symbol type. + elfcpp::STT type; + // The symbol binding. + elfcpp::STB binding; + // The symbol visibility. + elfcpp::STV visibility; + // The rest of the st_other field. + unsigned char nonvis; + // If true, the value field is an offset from the end of the output + // section. + bool offset_is_from_end; + // If true, this symbol is defined only if we see a reference to it. + bool only_if_ref; +}; + +// A struct describing a symbol defined by the linker, where the value +// of the symbol is defined based on a segment. This is used for +// symbols defined by the linker, like "_end". We describe the +// segment with which the symbol should be associated by its +// characteristics. If no segment meets these characteristics, the +// symbol will be defined as zero. If there is more than one segment +// which meets these characteristics, we will use the first one. + +struct Define_symbol_in_segment +{ + // The symbol name. + const char* name; + // The segment type where the symbol should be defined, typically + // PT_LOAD. + elfcpp::PT segment_type; + // Bitmask of segment flags which must be set. + elfcpp::PF segment_flags_set; + // Bitmask of segment flags which must be clear. + elfcpp::PF segment_flags_clear; + // The offset of the symbol within the segment. The offset is + // calculated from the position set by offset_base. + uint64_t value; + // The size of the symbol. + uint64_t size; + // The symbol type. + elfcpp::STT type; + // The symbol binding. + elfcpp::STB binding; + // The symbol visibility. + elfcpp::STV visibility; + // The rest of the st_other field. + unsigned char nonvis; + // The base from which we compute the offset. + Symbol::Segment_offset_base offset_base; + // If true, this symbol is defined only if we see a reference to it. + bool only_if_ref; +}; + +// Specify an object/section/offset location. Used by ODR code. + +struct Symbol_location +{ + // Object where the symbol is defined. + Object* object; + // Section-in-object where the symbol is defined. + unsigned int shndx; + // For relocatable objects, offset-in-section where the symbol is defined. + // For dynamic objects, address where the symbol is defined. + off_t offset; + bool operator==(const Symbol_location& that) const + { + return (this->object == that.object + && this->shndx == that.shndx + && this->offset == that.offset); + } +}; + +// This class manages warnings. Warnings are a GNU extension. When +// we see a section named .gnu.warning.SYM in an object file, and if +// we wind using the definition of SYM from that object file, then we +// will issue a warning for any relocation against SYM from a +// different object file. The text of the warning is the contents of +// the section. This is not precisely the definition used by the old +// GNU linker; the old GNU linker treated an occurrence of +// .gnu.warning.SYM as defining a warning symbol. A warning symbol +// would trigger a warning on any reference. However, it was +// inconsistent in that a warning in a dynamic object only triggered +// if there was no definition in a regular object. This linker is +// different in that we only issue a warning if we use the symbol +// definition from the same object file as the warning section. + +class Warnings +{ + public: + Warnings() + : warnings_() + { } + + // Add a warning for symbol NAME in object OBJ. WARNING is the text + // of the warning. + void + add_warning(Symbol_table* symtab, const char* name, Object* obj, + const std::string& warning); + + // For each symbol for which we should give a warning, make a note + // on the symbol. + void + note_warnings(Symbol_table* symtab); + + // Issue a warning for a reference to SYM at RELINFO's location. + template<int size, bool big_endian> + void + issue_warning(const Symbol* sym, const Relocate_info<size, big_endian>*, + size_t relnum, off_t reloffset) const; + + private: + Warnings(const Warnings&); + Warnings& operator=(const Warnings&); + + // What we need to know to get the warning text. + struct Warning_location + { + // The object the warning is in. + Object* object; + // The warning text. + std::string text; + + Warning_location() + : object(NULL), text() + { } + + void + set(Object* o, const std::string& t) + { + this->object = o; + this->text = t; + } + }; + + // A mapping from warning symbol names (canonicalized in + // Symbol_table's namepool_ field) to warning information. + typedef Unordered_map<const char*, Warning_location> Warning_table; + + Warning_table warnings_; +}; + +// The main linker symbol table. + +class Symbol_table +{ + public: + // The different places where a symbol definition can come from. + enum Defined + { + // Defined in an object file--the normal case. + OBJECT, + // Defined for a COPY reloc. + COPY, + // Defined on the command line using --defsym. + DEFSYM, + // Defined (so to speak) on the command line using -u. + UNDEFINED, + // Defined in a linker script. + SCRIPT, + // Predefined by the linker. + PREDEFINED, + // Defined by the linker during an incremental base link, but not + // a predefined symbol (e.g., common, defined in script). + INCREMENTAL_BASE, + }; + + // The order in which we sort common symbols. + enum Sort_commons_order + { + SORT_COMMONS_BY_SIZE_DESCENDING, + SORT_COMMONS_BY_ALIGNMENT_DESCENDING, + SORT_COMMONS_BY_ALIGNMENT_ASCENDING + }; + + // COUNT is an estimate of how many symbols will be inserted in the + // symbol table. It's ok to put 0 if you don't know; a correct + // guess will just save some CPU by reducing hashtable resizes. + Symbol_table(unsigned int count, const Version_script_info& version_script); + + ~Symbol_table(); + + void + set_icf(Icf* icf) + { this->icf_ = icf;} + + Icf* + icf() const + { return this->icf_; } + + // Returns true if ICF determined that this is a duplicate section. + bool + is_section_folded(Object* obj, unsigned int shndx) const; + + void + set_gc(Garbage_collection* gc) + { this->gc_ = gc; } + + Garbage_collection* + gc() const + { return this->gc_; } + + // During garbage collection, this keeps undefined symbols. + void + gc_mark_undef_symbols(Layout*); + + // This tells garbage collection that this symbol is referenced. + void + gc_mark_symbol(Symbol* sym); + + // During garbage collection, this keeps sections that correspond to + // symbols seen in dynamic objects. + inline void + gc_mark_dyn_syms(Symbol* sym); + + // Add COUNT external symbols from the relocatable object RELOBJ to + // the symbol table. SYMS is the symbols, SYMNDX_OFFSET is the + // offset in the symbol table of the first symbol, SYM_NAMES is + // their names, SYM_NAME_SIZE is the size of SYM_NAMES. This sets + // SYMPOINTERS to point to the symbols in the symbol table. It sets + // *DEFINED to the number of defined symbols. + template<int size, bool big_endian> + void + add_from_relobj(Sized_relobj_file<size, big_endian>* relobj, + const unsigned char* syms, size_t count, + size_t symndx_offset, const char* sym_names, + size_t sym_name_size, + typename Sized_relobj_file<size, big_endian>::Symbols*, + size_t* defined); + + // Add one external symbol from the plugin object OBJ to the symbol table. + // Returns a pointer to the resolved symbol in the symbol table. + template<int size, bool big_endian> + Symbol* + add_from_pluginobj(Sized_pluginobj<size, big_endian>* obj, + const char* name, const char* ver, + elfcpp::Sym<size, big_endian>* sym); + + // Add COUNT dynamic symbols from the dynamic object DYNOBJ to the + // symbol table. SYMS is the symbols. SYM_NAMES is their names. + // SYM_NAME_SIZE is the size of SYM_NAMES. The other parameters are + // symbol version data. + template<int size, bool big_endian> + void + add_from_dynobj(Sized_dynobj<size, big_endian>* dynobj, + const unsigned char* syms, size_t count, + const char* sym_names, size_t sym_name_size, + const unsigned char* versym, size_t versym_size, + const std::vector<const char*>*, + typename Sized_relobj_file<size, big_endian>::Symbols*, + size_t* defined); + + // Add one external symbol from the incremental object OBJ to the symbol + // table. Returns a pointer to the resolved symbol in the symbol table. + template<int size, bool big_endian> + Sized_symbol<size>* + add_from_incrobj(Object* obj, const char* name, + const char* ver, elfcpp::Sym<size, big_endian>* sym); + + // Define a special symbol based on an Output_data. It is a + // multiple definition error if this symbol is already defined. + Symbol* + define_in_output_data(const char* name, const char* version, Defined, + Output_data*, uint64_t value, uint64_t symsize, + elfcpp::STT type, elfcpp::STB binding, + elfcpp::STV visibility, unsigned char nonvis, + bool offset_is_from_end, bool only_if_ref); + + // Define a special symbol based on an Output_segment. It is a + // multiple definition error if this symbol is already defined. + Symbol* + define_in_output_segment(const char* name, const char* version, Defined, + Output_segment*, uint64_t value, uint64_t symsize, + elfcpp::STT type, elfcpp::STB binding, + elfcpp::STV visibility, unsigned char nonvis, + Symbol::Segment_offset_base, bool only_if_ref); + + // Define a special symbol with a constant value. It is a multiple + // definition error if this symbol is already defined. + Symbol* + define_as_constant(const char* name, const char* version, Defined, + uint64_t value, uint64_t symsize, elfcpp::STT type, + elfcpp::STB binding, elfcpp::STV visibility, + unsigned char nonvis, bool only_if_ref, + bool force_override); + + // Define a set of symbols in output sections. If ONLY_IF_REF is + // true, only define them if they are referenced. + void + define_symbols(const Layout*, int count, const Define_symbol_in_section*, + bool only_if_ref); + + // Define a set of symbols in output segments. If ONLY_IF_REF is + // true, only defined them if they are referenced. + void + define_symbols(const Layout*, int count, const Define_symbol_in_segment*, + bool only_if_ref); + + // Define SYM using a COPY reloc. POSD is the Output_data where the + // symbol should be defined--typically a .dyn.bss section. VALUE is + // the offset within POSD. + template<int size> + void + define_with_copy_reloc(Sized_symbol<size>* sym, Output_data* posd, + typename elfcpp::Elf_types<size>::Elf_Addr); + + // Look up a symbol. + Symbol* + lookup(const char*, const char* version = NULL) const; + + // Return the real symbol associated with the forwarder symbol FROM. + Symbol* + resolve_forwards(const Symbol* from) const; + + // Return the sized version of a symbol in this table. + template<int size> + Sized_symbol<size>* + get_sized_symbol(Symbol*) const; + + template<int size> + const Sized_symbol<size>* + get_sized_symbol(const Symbol*) const; + + // Return the count of undefined symbols seen. + size_t + saw_undefined() const + { return this->saw_undefined_; } + + // Allocate the common symbols + void + allocate_commons(Layout*, Mapfile*); + + // Add a warning for symbol NAME in object OBJ. WARNING is the text + // of the warning. + void + add_warning(const char* name, Object* obj, const std::string& warning) + { this->warnings_.add_warning(this, name, obj, warning); } + + // Canonicalize a symbol name for use in the hash table. + const char* + canonicalize_name(const char* name) + { return this->namepool_.add(name, true, NULL); } + + // Possibly issue a warning for a reference to SYM at LOCATION which + // is in OBJ. + template<int size, bool big_endian> + void + issue_warning(const Symbol* sym, + const Relocate_info<size, big_endian>* relinfo, + size_t relnum, off_t reloffset) const + { this->warnings_.issue_warning(sym, relinfo, relnum, reloffset); } + + // Check candidate_odr_violations_ to find symbols with the same name + // but apparently different definitions (different source-file/line-no). + void + detect_odr_violations(const Task*, const char* output_file_name) const; + + // Add any undefined symbols named on the command line to the symbol + // table. + void + add_undefined_symbols_from_command_line(Layout*); + + // SYM is defined using a COPY reloc. Return the dynamic object + // where the original definition was found. + Dynobj* + get_copy_source(const Symbol* sym) const; + + // Set the dynamic symbol indexes. INDEX is the index of the first + // global dynamic symbol. Pointers to the symbols are stored into + // the vector. The names are stored into the Stringpool. This + // returns an updated dynamic symbol index. + unsigned int + set_dynsym_indexes(unsigned int index, std::vector<Symbol*>*, + Stringpool*, Versions*); + + // Finalize the symbol table after we have set the final addresses + // of all the input sections. This sets the final symbol indexes, + // values and adds the names to *POOL. *PLOCAL_SYMCOUNT is the + // index of the first global symbol. OFF is the file offset of the + // global symbol table, DYNOFF is the offset of the globals in the + // dynamic symbol table, DYN_GLOBAL_INDEX is the index of the first + // global dynamic symbol, and DYNCOUNT is the number of global + // dynamic symbols. This records the parameters, and returns the + // new file offset. It updates *PLOCAL_SYMCOUNT if it created any + // local symbols. + off_t + finalize(off_t off, off_t dynoff, size_t dyn_global_index, size_t dyncount, + Stringpool* pool, unsigned int* plocal_symcount); + + // Set the final file offset of the symbol table. + void + set_file_offset(off_t off) + { this->offset_ = off; } + + // Status code of Symbol_table::compute_final_value. + enum Compute_final_value_status + { + // No error. + CFVS_OK, + // Unsupported symbol section. + CFVS_UNSUPPORTED_SYMBOL_SECTION, + // No output section. + CFVS_NO_OUTPUT_SECTION + }; + + // Compute the final value of SYM and store status in location PSTATUS. + // During relaxation, this may be called multiple times for a symbol to + // compute its would-be final value in each relaxation pass. + + template<int size> + typename Sized_symbol<size>::Value_type + compute_final_value(const Sized_symbol<size>* sym, + Compute_final_value_status* pstatus) const; + + // Return the index of the first global symbol. + unsigned int + first_global_index() const + { return this->first_global_index_; } + + // Return the total number of symbols in the symbol table. + unsigned int + output_count() const + { return this->output_count_; } + + // Write out the global symbols. + void + write_globals(const Stringpool*, const Stringpool*, + Output_symtab_xindex*, Output_symtab_xindex*, + Output_file*) const; + + // Write out a section symbol. Return the updated offset. + void + write_section_symbol(const Output_section*, Output_symtab_xindex*, + Output_file*, off_t) const; + + // Loop over all symbols, applying the function F to each. + template<int size, typename F> + void + for_all_symbols(F f) const + { + for (Symbol_table_type::const_iterator p = this->table_.begin(); + p != this->table_.end(); + ++p) + { + Sized_symbol<size>* sym = static_cast<Sized_symbol<size>*>(p->second); + f(sym); + } + } + + // Dump statistical information to stderr. + void + print_stats() const; + + // Return the version script information. + const Version_script_info& + version_script() const + { return version_script_; } + + private: + Symbol_table(const Symbol_table&); + Symbol_table& operator=(const Symbol_table&); + + // The type of the list of common symbols. + typedef std::vector<Symbol*> Commons_type; + + // The type of the symbol hash table. + + typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key; + + // The hash function. The key values are Stringpool keys. + struct Symbol_table_hash + { + inline size_t + operator()(const Symbol_table_key& key) const + { + return key.first ^ key.second; + } + }; + + struct Symbol_table_eq + { + bool + operator()(const Symbol_table_key&, const Symbol_table_key&) const; + }; + + typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash, + Symbol_table_eq> Symbol_table_type; + + // A map from symbol name (as a pointer into the namepool) to all + // the locations the symbols is (weakly) defined (and certain other + // conditions are met). This map will be used later to detect + // possible One Definition Rule (ODR) violations. + struct Symbol_location_hash + { + size_t operator()(const Symbol_location& loc) const + { return reinterpret_cast<uintptr_t>(loc.object) ^ loc.offset ^ loc.shndx; } + }; + + typedef Unordered_map<const char*, + Unordered_set<Symbol_location, Symbol_location_hash> > + Odr_map; + + // Make FROM a forwarder symbol to TO. + void + make_forwarder(Symbol* from, Symbol* to); + + // Add a symbol. + template<int size, bool big_endian> + Sized_symbol<size>* + add_from_object(Object*, const char* name, Stringpool::Key name_key, + const char* version, Stringpool::Key version_key, + bool def, const elfcpp::Sym<size, big_endian>& sym, + unsigned int st_shndx, bool is_ordinary, + unsigned int orig_st_shndx); + + // Define a default symbol. + template<int size, bool big_endian> + void + define_default_version(Sized_symbol<size>*, bool, + Symbol_table_type::iterator); + + // Resolve symbols. + template<int size, bool big_endian> + void + resolve(Sized_symbol<size>* to, + const elfcpp::Sym<size, big_endian>& sym, + unsigned int st_shndx, bool is_ordinary, + unsigned int orig_st_shndx, + Object*, const char* version); + + template<int size, bool big_endian> + void + resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from); + + // Record that a symbol is forced to be local by a version script or + // by visibility. + void + force_local(Symbol*); + + // Adjust NAME and *NAME_KEY for wrapping. + const char* + wrap_symbol(const char* name, Stringpool::Key* name_key); + + // Whether we should override a symbol, based on flags in + // resolve.cc. + static bool + should_override(const Symbol*, unsigned int, elfcpp::STT, Defined, + Object*, bool*, bool*); + + // Report a problem in symbol resolution. + static void + report_resolve_problem(bool is_error, const char* msg, const Symbol* to, + Defined, Object* object); + + // Override a symbol. + template<int size, bool big_endian> + void + override(Sized_symbol<size>* tosym, + const elfcpp::Sym<size, big_endian>& fromsym, + unsigned int st_shndx, bool is_ordinary, + Object* object, const char* version); + + // Whether we should override a symbol with a special symbol which + // is automatically defined by the linker. + static bool + should_override_with_special(const Symbol*, elfcpp::STT, Defined); + + // Override a symbol with a special symbol. + template<int size> + void + override_with_special(Sized_symbol<size>* tosym, + const Sized_symbol<size>* fromsym); + + // Record all weak alias sets for a dynamic object. + template<int size> + void + record_weak_aliases(std::vector<Sized_symbol<size>*>*); + + // Define a special symbol. + template<int size, bool big_endian> + Sized_symbol<size>* + define_special_symbol(const char** pname, const char** pversion, + bool only_if_ref, Sized_symbol<size>** poldsym, + bool* resolve_oldsym); + + // Define a symbol in an Output_data, sized version. + template<int size> + Sized_symbol<size>* + do_define_in_output_data(const char* name, const char* version, Defined, + Output_data*, + typename elfcpp::Elf_types<size>::Elf_Addr value, + typename elfcpp::Elf_types<size>::Elf_WXword ssize, + elfcpp::STT type, elfcpp::STB binding, + elfcpp::STV visibility, unsigned char nonvis, + bool offset_is_from_end, bool only_if_ref); + + // Define a symbol in an Output_segment, sized version. + template<int size> + Sized_symbol<size>* + do_define_in_output_segment( + const char* name, const char* version, Defined, Output_segment* os, + typename elfcpp::Elf_types<size>::Elf_Addr value, + typename elfcpp::Elf_types<size>::Elf_WXword ssize, + elfcpp::STT type, elfcpp::STB binding, + elfcpp::STV visibility, unsigned char nonvis, + Symbol::Segment_offset_base offset_base, bool only_if_ref); + + // Define a symbol as a constant, sized version. + template<int size> + Sized_symbol<size>* + do_define_as_constant( + const char* name, const char* version, Defined, + typename elfcpp::Elf_types<size>::Elf_Addr value, + typename elfcpp::Elf_types<size>::Elf_WXword ssize, + elfcpp::STT type, elfcpp::STB binding, + elfcpp::STV visibility, unsigned char nonvis, + bool only_if_ref, bool force_override); + + // Add any undefined symbols named on the command line to the symbol + // table, sized version. + template<int size> + void + do_add_undefined_symbols_from_command_line(Layout*); + + // Add one undefined symbol. + template<int size> + void + add_undefined_symbol_from_command_line(const char* name); + + // Types of common symbols. + + enum Commons_section_type + { + COMMONS_NORMAL, + COMMONS_TLS, + COMMONS_SMALL, + COMMONS_LARGE + }; + + // Allocate the common symbols, sized version. + template<int size> + void + do_allocate_commons(Layout*, Mapfile*, Sort_commons_order); + + // Allocate the common symbols from one list. + template<int size> + void + do_allocate_commons_list(Layout*, Commons_section_type, Commons_type*, + Mapfile*, Sort_commons_order); + + // Returns all of the lines attached to LOC, not just the one the + // instruction actually came from. This helps the ODR checker avoid + // false positives. + static std::vector<std::string> + linenos_from_loc(const Task* task, const Symbol_location& loc); + + // Implement detect_odr_violations. + template<int size, bool big_endian> + void + sized_detect_odr_violations() const; + + // Finalize symbols specialized for size. + template<int size> + off_t + sized_finalize(off_t, Stringpool*, unsigned int*); + + // Finalize a symbol. Return whether it should be added to the + // symbol table. + template<int size> + bool + sized_finalize_symbol(Symbol*); + + // Add a symbol the final symtab by setting its index. + template<int size> + void + add_to_final_symtab(Symbol*, Stringpool*, unsigned int* pindex, off_t* poff); + + // Write globals specialized for size and endianness. + template<int size, bool big_endian> + void + sized_write_globals(const Stringpool*, const Stringpool*, + Output_symtab_xindex*, Output_symtab_xindex*, + Output_file*) const; + + // Write out a symbol to P. + template<int size, bool big_endian> + void + sized_write_symbol(Sized_symbol<size>*, + typename elfcpp::Elf_types<size>::Elf_Addr value, + unsigned int shndx, elfcpp::STB, + const Stringpool*, unsigned char* p) const; + + // Possibly warn about an undefined symbol from a dynamic object. + void + warn_about_undefined_dynobj_symbol(Symbol*) const; + + // Write out a section symbol, specialized for size and endianness. + template<int size, bool big_endian> + void + sized_write_section_symbol(const Output_section*, Output_symtab_xindex*, + Output_file*, off_t) const; + + // The type of the list of symbols which have been forced local. + typedef std::vector<Symbol*> Forced_locals; + + // A map from symbols with COPY relocs to the dynamic objects where + // they are defined. + typedef Unordered_map<const Symbol*, Dynobj*> Copied_symbol_dynobjs; + + // We increment this every time we see a new undefined symbol, for + // use in archive groups. + size_t saw_undefined_; + // The index of the first global symbol in the output file. + unsigned int first_global_index_; + // The file offset within the output symtab section where we should + // write the table. + off_t offset_; + // The number of global symbols we want to write out. + unsigned int output_count_; + // The file offset of the global dynamic symbols, or 0 if none. + off_t dynamic_offset_; + // The index of the first global dynamic symbol. + unsigned int first_dynamic_global_index_; + // The number of global dynamic symbols, or 0 if none. + unsigned int dynamic_count_; + // The symbol hash table. + Symbol_table_type table_; + // A pool of symbol names. This is used for all global symbols. + // Entries in the hash table point into this pool. + Stringpool namepool_; + // Forwarding symbols. + Unordered_map<const Symbol*, Symbol*> forwarders_; + // Weak aliases. A symbol in this list points to the next alias. + // The aliases point to each other in a circular list. + Unordered_map<Symbol*, Symbol*> weak_aliases_; + // We don't expect there to be very many common symbols, so we keep + // a list of them. When we find a common symbol we add it to this + // list. It is possible that by the time we process the list the + // symbol is no longer a common symbol. It may also have become a + // forwarder. + Commons_type commons_; + // This is like the commons_ field, except that it holds TLS common + // symbols. + Commons_type tls_commons_; + // This is for small common symbols. + Commons_type small_commons_; + // This is for large common symbols. + Commons_type large_commons_; + // A list of symbols which have been forced to be local. We don't + // expect there to be very many of them, so we keep a list of them + // rather than walking the whole table to find them. + Forced_locals forced_locals_; + // Manage symbol warnings. + Warnings warnings_; + // Manage potential One Definition Rule (ODR) violations. + Odr_map candidate_odr_violations_; + + // When we emit a COPY reloc for a symbol, we define it in an + // Output_data. When it's time to emit version information for it, + // we need to know the dynamic object in which we found the original + // definition. This maps symbols with COPY relocs to the dynamic + // object where they were defined. + Copied_symbol_dynobjs copied_symbol_dynobjs_; + // Information parsed from the version script, if any. + const Version_script_info& version_script_; + Garbage_collection* gc_; + Icf* icf_; +}; + +// We inline get_sized_symbol for efficiency. + +template<int size> +Sized_symbol<size>* +Symbol_table::get_sized_symbol(Symbol* sym) const +{ + gold_assert(size == parameters->target().get_size()); + return static_cast<Sized_symbol<size>*>(sym); +} + +template<int size> +const Sized_symbol<size>* +Symbol_table::get_sized_symbol(const Symbol* sym) const +{ + gold_assert(size == parameters->target().get_size()); + return static_cast<const Sized_symbol<size>*>(sym); +} + +} // End namespace gold. + +#endif // !defined(GOLD_SYMTAB_H) |