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- // symtab.h -- the gold symbol table -*- C++ -*-
- // Copyright (C) 2006-2022 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; }
- // Set that this version is not the default for this symbol name.
- void
- set_is_not_default()
- { this->is_def_ = false; }
- // 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->u1_.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->u2_.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->u1_.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->u2_.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->u1_.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->u2_.offset_base;
- }
- // Return the symbol binding.
- elfcpp::STB
- binding() const
- { return this->binding_; }
- // Return the symbol type.
- elfcpp::STT
- type() const
- { return this->type_; }
- // Set the symbol type.
- void
- set_type(elfcpp::STT type)
- { this->type_ = 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 or by a special symbol.
- 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 or
- // by a special symbol.
- 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_; }
- // Set the non-visibility part of the st_other field.
- void
- set_nonvis(unsigned int nonvis)
- { this->nonvis_ = 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; }
- // Forget this symbol was seen in a regular object.
- void
- clear_in_reg()
- { this->in_reg_ = false; }
- // 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 is defined in a dynamic object.
- bool
- from_dyn() const
- { return this->source_ == FROM_OBJECT && this->object()->is_dynamic(); }
- // 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, uint64_t addend = 0) const
- { return this->got_offsets_.get_offset(got_type, addend) != -1U; }
- // Return the offset into the GOT section of this symbol.
- unsigned int
- got_offset(unsigned int got_type, uint64_t addend = 0) const
- {
- unsigned int got_offset = this->got_offsets_.get_offset(got_type, addend);
- 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,
- uint64_t addend = 0)
- { this->got_offsets_.set_offset(got_type, got_offset, addend); }
- // 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
- || this->is_undef_binding_weak()
- || parameters->options().weak_unresolved_symbols()));
- }
- // Return whether this is a strong undefined symbol.
- bool
- is_strong_undefined() const
- {
- return (this->is_undefined()
- && this->binding() != elfcpp::STB_WEAK
- && !this->is_undef_binding_weak()
- && !parameters->options().weak_unresolved_symbols());
- }
- // 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;
- 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 symbol was named in a --dynamic-list script, it is preemptible.
- if (parameters->options().in_dynamic_list(this->name()))
- return true;
- // If the user used -Bsymbolic, then nothing (else) 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,
- // When set, says that dynamic relocations are needed even if a
- // symbol has a plt entry.
- FUNC_DESC_ABI = 16,
- };
- // 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 (!(flags & FUNC_DESC_ABI)
- && !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*);
- // Set the symbol's output segment. This is used for pre-defined
- // symbols whose segments aren't known until after layout is done
- // (e.g., __ehdr_start).
- void
- set_output_segment(Output_segment*, Segment_offset_base);
- // Set the symbol to undefined. This is used for pre-defined
- // symbols whose segments aren't known until after layout is done
- // (e.g., __ehdr_start).
- void
- set_undefined();
- // 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().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_); }
- // Return true if this symbol is protected in a shared object.
- // This is not the same as checking if visibility() == elfcpp::STV_PROTECTED,
- // because the visibility_ field reflects the symbol's visibility from
- // outside the shared object.
- bool
- is_protected() const
- { return this->is_protected_; }
- // Mark this symbol as protected in a shared object.
- void
- set_is_protected()
- { this->is_protected_ = true; }
- // Return state of PowerPC64 ELFv2 specific flag.
- bool
- non_zero_localentry() const
- { return this->non_zero_localentry_; }
- // Set PowerPC64 ELFv2 specific flag.
- void
- set_non_zero_localentry()
- { this->non_zero_localentry_ = true; }
- // Completely override existing symbol. Everything bar name_,
- // version_, and is_forced_local_ flag are copied. version_ is
- // cleared if from->version_ is clear. Returns true if this symbol
- // should be forced local.
- bool
- clone(const Symbol* from);
- protected:
- // Instances of this class should always be created at a specific
- // size.
- Symbol()
- { memset(static_cast<void*>(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 is used if SOURCE_ == FROM_OBJECT.
- // Object in which symbol is defined, or in which it was first
- // seen.
- Object* object;
- // This is used if SOURCE_ == IN_OUTPUT_DATA.
- // 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;
- // This is used if SOURCE_ == IN_OUTPUT_SEGMENT.
- // Output_segment in which the symbol is defined. Before
- // Layout::finalize the symbol's value is an offset.
- Output_segment* output_segment;
- } u1_;
- union
- {
- // This is used if SOURCE_ == FROM_OBJECT.
- // Section number in object in which symbol is defined.
- unsigned int shndx;
- // This is used if SOURCE_ == IN_OUTPUT_DATA.
- // True if the offset is from the end, false if the offset is
- // from the beginning.
- bool offset_is_from_end;
- // This is used if SOURCE_ == IN_OUTPUT_SEGMENT.
- // The base to use for the offset before Layout::finalize.
- Segment_offset_base offset_base;
- } u2_;
- // 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_;
- // 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_;
- // 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_;
- // 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 u2_.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
- // or by a special symbol (bit 33).
- bool undef_binding_weak_ : 1;
- // True if this symbol is a predefined linker symbol (bit 34).
- bool is_predefined_ : 1;
- // True if this symbol has protected visibility in a shared object (bit 35).
- // The visibility_ field will be STV_DEFAULT in this case because we
- // must treat it as such from outside the shared object.
- bool is_protected_ : 1;
- // Used by PowerPC64 ELFv2 to track st_other localentry (bit 36).
- bool non_zero_localentry_ : 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, Value_type value,
- 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);
- // Completely override existing symbol. Everything bar name_,
- // version_, and is_forced_local_ flag are copied. version_ is
- // cleared if from->version_ is clear. Returns true if this symbol
- // should be forced local.
- bool
- clone(const Sized_symbol<size>* from);
- 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);
- }
- };
- // 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; }
- };
- // 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(Relobj* 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);
- // Add a target-specific global symbol.
- // (Used by SPARC backend to add STT_SPARC_REGISTER symbols.)
- void
- add_target_global_symbol(Symbol* sym)
- { this->target_symbols_.push_back(sym); }
- // 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_; }
- void
- set_has_gnu_output()
- { this->has_gnu_output_ = true; }
- // 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. Return the count of forced-local symbols in
- // *PFORCED_LOCAL_COUNT. 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, unsigned int* pforced_local_count,
- 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_; }
- // Completely override existing symbol.
- template<int size>
- void
- clone(Sized_symbol<size>* to, const Sized_symbol<size>* from)
- {
- if (to->clone(from))
- this->force_local(to);
- }
- 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;
- 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,
- bool is_default_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*, 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, elfcpp::STV visibility,
- Sized_symbol<size>** poldsym,
- bool* resolve_oldsym, bool is_forced_local);
- // 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 (including
- // forced-local symbols).
- unsigned int first_dynamic_global_index_;
- // The number of global dynamic symbols (including forced-local symbols),
- // or 0 if none.
- unsigned int dynamic_count_;
- // Set if a STT_GNU_IFUNC or STB_GNU_UNIQUE symbol will be output.
- bool has_gnu_output_;
- // 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_;
- // Target-specific symbols, if any.
- std::vector<Symbol*> target_symbols_;
- };
- // 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)
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