// symtab.h -- the gold symbol table -*- C++ -*-
+// Copyright (C) 2006-2020 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 <cassert>
+#include <vector>
#include "elfcpp.h"
+#include "parameters.h"
#include "stringpool.h"
-
-#ifndef GOLD_SYMTAB_H
-#define GOLD_SYMTAB_H
+#include "object.h"
namespace gold
{
+class Mapfile;
class Object;
-class Output_file;
-class Target;
-
+class Relobj;
+template<int size, bool big_endian>
+class Sized_relobj_file;
template<int size, bool big_endian>
-class Sized_object;
+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 to big.
+// 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
- { return this->object_; }
+ {
+ 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
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
- other() const
- { return this->other_; }
+ nonvis() const
+ { return this->nonvis_; }
- // Return the section index.
- unsigned int
- shnum() const
- { return this->shnum_; }
+ // 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
set_forwarder()
{ this->is_forwarder_ = true; }
- // Return whether this symbol was seen in a dynamic object.
+ // 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 seen in a dynamic object.
+ // 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) 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
+ || 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 fields from an ELF symbol in OBJECT.
+ // 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(const char *name, const char* version, Object* object,
- const elfcpp::Sym<size, big_endian>&);
+ 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>&, Object* object);
+ 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 version (expected to point into a Stringpool). This may
// be NULL.
const char* version_;
- // 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 shnum_;
- // Symbol type.
+
+ 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.
+ // Symbol binding (bits 4 to 7).
elfcpp::STB binding_ : 4;
- // Symbol visibility.
+ // Symbol visibility (bits 8 to 9).
elfcpp::STV visibility_ : 2;
- // Rest of symbol st_other field.
- unsigned int other_ : 6;
- // True if this symbol always requires special target-specific
- // handling.
- bool is_special_ : 1;
- // True if this is the default version of the symbol.
+ // 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
// 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.
+ // Symbol_table (bit 20).
bool is_forwarder_ : 1;
- // True if we've seen this symbol in a dynamic object.
+ // 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
Sized_symbol()
{ }
- // Initialize fields from an ELF symbol in OBJECT.
+ // 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(const char *name, const char* version, Object* object,
- const elfcpp::Sym<size, big_endian>&);
+ 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>&, Object* object);
+ 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
// is a template parameter).
Size_type
symsize() const
- { return this->size_; }
+ { 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.
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.
+ // 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 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:
- Symbol_table();
+ // 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();
- // Add COUNT external symbols from OBJECT to the symbol table. SYMS
- // is the symbols, 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.
+ 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_object(Sized_object<size, big_endian>* object,
- const elfcpp::Sym<size, big_endian>* syms,
- size_t count, const char* sym_names, size_t sym_name_size,
- Symbol** sympointers);
+ 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*
// Return the real symbol associated with the forwarder symbol FROM.
Symbol*
- resolve_forwards(Symbol* from) const;
-
- // Return the size of the symbols in the table.
- int
- get_size() const
- { return this->size_; }
+ resolve_forwards(const Symbol* from) const;
// Return the sized version of a symbol in this table.
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 values and
- // adds the names to *POOL. It records the file offset OFF, and
- // returns the new file offset.
+ // 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, Stringpool*);
+ 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 Target*, const Stringpool*, Output_file*) const;
+ 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&);
- // Set the size of the symbols in the table.
- void
- set_size(int size)
- { this->size_ = size; }
+ // 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
// Add a symbol.
template<int size, bool big_endian>
- Symbol*
- add_from_object(Sized_object<size, big_endian>*, const char *name,
- const char *version, bool def,
- const elfcpp::Sym<size, big_endian>& sym);
+ 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>
- static void
+ void
resolve(Sized_symbol<size>* to,
const elfcpp::Sym<size, big_endian>& sym,
- Object*);
+ unsigned int st_shndx, bool is_ordinary,
+ unsigned int orig_st_shndx,
+ Object*, const char* version,
+ bool is_default_version);
-#ifdef HAVE_MEMBER_TEMPLATE_SPECIFICATIONS
template<int size, bool big_endian>
- static void
+ void
resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from);
-#else
- template<int size>
+
+ // 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
- resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from,
- bool big_endian);
-#endif
+ report_resolve_problem(bool is_error, const char* msg, const Symbol* to,
+ Defined, Object* object);
- // Finalize symbols specialized for size.
+ // 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>
- off_t
- sized_finalize(off_t, Stringpool*);
+ void
+ override_with_special(Sized_symbol<size>* tosym,
+ const Sized_symbol<size>* fromsym);
- // Write globals specialized for size and endianness.
+ // 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
- sized_write_globals(const Target*, const Stringpool*, Output_file*) const;
+ do_add_undefined_symbols_from_command_line(Layout*);
- // The type of the symbol hash table.
+ // Add one undefined symbol.
+ template<int size>
+ void
+ add_undefined_symbol_from_command_line(const char* name);
- typedef std::pair<const char*, const char*> Symbol_table_key;
+ // Types of common symbols.
- struct Symbol_table_hash
+ enum Commons_section_type
{
- size_t
- operator()(const Symbol_table_key&) const;
+ COMMONS_NORMAL,
+ COMMONS_TLS,
+ COMMONS_SMALL,
+ COMMONS_LARGE
};
- struct Symbol_table_eq
- {
- bool
- operator()(const Symbol_table_key&, const Symbol_table_key&) const;
- };
+ // Allocate the common symbols, sized version.
+ template<int size>
+ void
+ do_allocate_commons(Layout*, Mapfile*, Sort_commons_order);
- typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
- Symbol_table_eq> Symbol_table_type;
+ // 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);
- // The size of the symbols in the symbol table (32 or 64).
- int size_;
+ // 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.
- size_t output_count_;
-
+ 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<Symbol*, Symbol*> forwarders_;
+ 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.
Sized_symbol<size>*
Symbol_table::get_sized_symbol(Symbol* sym) const
{
- assert(size == this->get_size());
+ gold_assert(size == parameters->target().get_size());
return static_cast<Sized_symbol<size>*>(sym);
}
const Sized_symbol<size>*
Symbol_table::get_sized_symbol(const Symbol* sym) const
{
- assert(size == this->get_size());
+ gold_assert(size == parameters->target().get_size());
return static_cast<const Sized_symbol<size>*>(sym);
}
projects / deliverable / binutils-gdb.git / blobdiff