// symtab.h -- the gold symbol table -*- C++ -*-
-// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
// Symbol_table
// The symbol table.
+#ifndef GOLD_SYMTAB_H
+#define GOLD_SYMTAB_H
+
#include <string>
#include <utility>
#include <vector>
#include "stringpool.h"
#include "object.h"
-#ifndef GOLD_SYMTAB_H
-#define GOLD_SYMTAB_H
-
namespace gold
{
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.
type() const
{ return this->type_; }
+ // Return true for function symbol.
+ bool
+ is_func() const
+ {
+ return (this->type_ == elfcpp::STT_FUNC
+ || this->type_ == elfcpp::STT_GNU_IFUNC);
+ }
+
// Return the symbol visibility.
elfcpp::STV
visibility() const
{ return this->visibility_; }
+ // Set the visibility.
+ void
+ set_visibility(elfcpp::STV visibility)
+ { this->visibility_ = visibility; }
+
+ // Override symbol visibility.
+ void
+ override_visibility(elfcpp::STV);
+
+ // Set whether the symbol was originally a weak undef or a regular undef
+ // when resolved by a dynamic def.
+ inline void
+ set_undef_binding(elfcpp::STB bind)
+ {
+ if (!this->undef_binding_set_ || this->undef_binding_weak_)
+ {
+ this->undef_binding_weak_ = bind == elfcpp::STB_WEAK;
+ this->undef_binding_set_ = true;
+ }
+ }
+
+ // Return TRUE if a weak undef was resolved by a dynamic def.
+ inline bool
+ is_undef_binding_weak() const
+ { return this->undef_binding_weak_; }
+
// Return the non-visibility part of the st_other field.
unsigned char
nonvis() const
needs_dynsym_entry() const
{
return (this->needs_dynsym_entry_
- || (this->in_reg() && this->in_dyn()));
+ || (this->in_reg()
+ && this->in_dyn()
+ && this->is_externally_visible()));
}
// Mark this symbol as needing an entry in the dynamic symbol table.
// Return whether this symbol should be added to the dynamic symbol
// table.
bool
- should_add_dynsym_entry() const;
+ should_add_dynsym_entry(Symbol_table*) const;
// Return whether this symbol has been seen in a regular object.
bool
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
// Return whether this symbol has an entry in the PLT section.
bool
has_plt_offset() const
- { return this->has_plt_offset_; }
+ { return this->plt_offset_ != -1U; }
// Return the offset into the PLT section of this symbol.
unsigned int
void
set_plt_offset(unsigned int plt_offset)
{
- this->has_plt_offset_ = true;
+ gold_assert(plt_offset != -1U);
this->plt_offset_ = plt_offset;
}
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
unsigned int shndx = this->shndx(&is_ordinary);
return (is_ordinary
? shndx != elfcpp::SHN_UNDEF
- : shndx != elfcpp::SHN_COMMON);
+ : !Symbol::is_common_shndx(shndx));
}
// Return true if this symbol is from a dynamic object.
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_common() const
{
+ if (this->source_ != FROM_OBJECT)
+ return false;
+ if (this->type_ == elfcpp::STT_COMMON)
+ return true;
bool is_ordinary;
- return (this->source_ == FROM_OBJECT
- && ((this->shndx(&is_ordinary) == elfcpp::SHN_COMMON
- && !is_ordinary)
- || this->type_ == elfcpp::STT_COMMON));
+ 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.
// Return true if this symbol is a function that needs a PLT entry.
// If the symbol is defined in a dynamic object or if it is subject
// to pre-emption, we need to make a PLT entry. If we're doing a
- // static link, we don't create PLT entries.
+ // static link or a -pie link, we don't create PLT entries.
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;
+
return (!parameters->doing_static_link()
- && this->type() == elfcpp::STT_FUNC
+ && !parameters->options().pie()
+ && this->is_func()
&& (this->is_from_dynobj()
|| this->is_undefined()
|| this->is_preemptible()));
if (parameters->doing_static_link())
return false;
- // A reference to a weak undefined symbol from an executable should be
+ // 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_weak_undefined() && !parameters->options().shared())
+ if (this->is_undefined() && !parameters->options().shared())
return false;
// A reference to an absolute symbol does not need a dynamic relocation.
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().shared()
+ && parameters->options().copyreloc()
+ && this->is_from_dynobj()
+ && !this->is_func());
+ }
+
protected:
// Instances of this class should always be created at a specific
// size.
// non-zero value during Layout::finalize.
unsigned int dynsym_index_;
- // If this symbol has an entry in the GOT section (has_got_offset_
- // is true), this holds the offset from the start of the GOT section.
- // 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.
+ // The GOT section entries for this symbol. A symbol may have more
+ // than one GOT offset (e.g., when mixing modules compiled with two
+ // different TLS models), but will usually have at most one.
Got_offset_list got_offsets_;
- // If this symbol has an entry in the PLT section (has_plt_offset_
- // is true), then this is the offset from the start of the PLT
- // section.
+ // If this symbol has an entry in the PLT section, then this is the
+ // offset from the start of the PLT section. This is -1U if there
+ // is no PLT entry.
unsigned int plt_offset_;
// Symbol type (bits 0 to 3).
unsigned int nonvis_ : 6;
// The type of symbol (bits 16 to 18).
Source source_ : 3;
- // True if this symbol always requires special target-specific
- // handling (bit 19).
- bool is_target_special_ : 1;
- // True if this is the default version of the symbol (bit 20).
+ // 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 (bit 21).
+ // Symbol_table (bit 20).
bool is_forwarder_ : 1;
// True if the symbol has an alias in the weak_aliases table in
- // Symbol_table (bit 22).
+ // Symbol_table (bit 21).
bool has_alias_ : 1;
// True if this symbol needs to be in the dynamic symbol table (bit
- // 23).
+ // 22).
bool needs_dynsym_entry_ : 1;
- // True if we've seen this symbol in a regular object (bit 24).
+ // 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 25).
+ // True if we've seen this symbol in a dynamic object (bit 24).
bool in_dyn_ : 1;
- // True if the symbol has an entry in the PLT section (bit 26).
- bool has_plt_offset_ : 1;
// True if this is a dynamic symbol which needs a special value in
- // the dynamic symbol table (bit 27).
+ // the dynamic symbol table (bit 25).
bool needs_dynsym_value_ : 1;
- // True if there is a warning for this symbol (bit 28).
+ // 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 29).
+ // 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 30).
+ // script (bit 28).
bool is_forced_local_ : 1;
// True if the field u_.from_object.shndx is an ordinary section
// index, not one of the special codes from SHN_LORESERVE to
- // SHN_HIRESERVE (bit 31).
+ // SHN_HIRESERVE (bit 29).
bool is_ordinary_shndx_ : 1;
- // True if we've seen this symbol in a real ELF object.
+ // True if we've seen this symbol in a real ELF object (bit 30).
bool in_real_elf_ : 1;
+ // True if this symbol is defined in a section which was discarded
+ // (bit 31).
+ bool is_defined_in_discarded_section_ : 1;
+ // True if UNDEF_BINDING_WEAK_ has been set (bit 32).
+ bool undef_binding_set_ : 1;
+ // True if this symbol was a weak undef resolved by a dynamic def
+ // (bit 33).
+ bool undef_binding_weak_ : 1;
};
// The parts of a symbol which are size specific. Using a template
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,
+ };
+
+ // 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 symbosl 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();
+ void
+ set_icf(Icf* icf)
+ { this->icf_ = icf;}
+
+ Icf*
+ icf() const
+ { return this->icf_; }
+
+ // Returns true if ICF determined that this is a duplicate section.
+ bool
+ is_section_folded(Object* obj, unsigned int shndx) const;
+
+ void
+ set_gc(Garbage_collection* gc)
+ { this->gc_ = gc; }
+
+ Garbage_collection*
+ gc() const
+ { return this->gc_; }
+
+ // During garbage collection, this keeps undefined symbols.
+ void
+ gc_mark_undef_symbols(Layout*);
+
+ // During garbage collection, this ensures externally visible symbols
+ // are not treated as garbage while building shared objects.
+ void
+ gc_mark_symbol_for_shlib(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
// 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,
+ 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,
// 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,
+ 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,
// 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,
+ 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,
get_sized_symbol(const Symbol*) const;
// Return the count of undefined symbols seen.
- int
+ size_t
saw_undefined() const
{ return this->saw_undefined_; }
// Add any undefined symbols named on the command line to the symbol
// table.
void
- add_undefined_symbols_from_command_line();
+ add_undefined_symbols_from_command_line(Layout*);
// SYM is defined using a COPY reloc. Return the dynamic object
// where the original definition was found.
finalize(off_t off, off_t dynoff, size_t dyn_global_index, size_t dyncount,
Stringpool* pool, unsigned int *plocal_symcount);
+ // Status code of Symbol_table::compute_final_value.
+ enum Compute_final_value_status
+ {
+ // No error.
+ CFVS_OK,
+ // Unspported 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;
+
// Write out the global symbols.
void
- write_globals(const Input_objects*, const Stringpool*, const Stringpool*,
+ write_globals(const Stringpool*, const Stringpool*,
Output_symtab_xindex*, Output_symtab_xindex*,
Output_file*) const;
// 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;
+
+ struct Symbol_table_hash
+ {
+ size_t
+ operator()(const Symbol_table_key&) const;
+ };
+
+ 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;
+
// Make FROM a forwarder symbol to TO.
void
make_forwarder(Symbol* from, Symbol* to);
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
void
resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from);
- // Record that a symbol is forced to be local by a version script.
+ // 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(Object* object, const char*, Stringpool::Key* name_key);
+ 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, Object*, bool*);
+ should_override(const Symbol*, unsigned int, Defined, Object*, bool*, bool*);
+
+ // Report a problem in symbol resolution.
+ static void
+ report_resolve_problem(bool is_error, const char* msg, const Symbol* to,
+ Defined, Object* object);
// Override a symbol.
template<int size, bool big_endian>
// 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*);
+ should_override_with_special(const Symbol*, Defined);
// Override a symbol with a special symbol.
template<int size>
template<int size, bool big_endian>
Sized_symbol<size>*
define_special_symbol(const char** pname, const char** pversion,
- bool only_if_ref, Sized_symbol<size>** poldsym);
+ bool only_if_ref, Sized_symbol<size>** poldsym,
+ bool* resolve_oldsym);
// Define a symbol in an Output_data, sized version.
template<int size>
Sized_symbol<size>*
- do_define_in_output_data(const char* name, const char* version, Output_data*,
+ 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,
template<int size>
Sized_symbol<size>*
do_define_in_output_segment(
- const char* name, const char* version, Output_segment* os,
+ 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,
template<int size>
Sized_symbol<size>*
do_define_as_constant(
- const char* name, const char* version,
+ 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,
// table, sized version.
template<int size>
void
- do_add_undefined_symbols_from_command_line();
+ 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*);
+ do_allocate_commons(Layout*, Mapfile*, Sort_commons_order);
// Allocate the common symbols from one list.
template<int size>
void
- do_allocate_commons_list(Layout*, bool is_tls, Commons_type*, Mapfile*);
+ do_allocate_commons_list(Layout*, Commons_section_type, Commons_type*,
+ Mapfile*, Sort_commons_order);
// Implement detect_odr_violations.
template<int size, bool big_endian>
// Write globals specialized for size and endianness.
template<int size, bool big_endian>
void
- sized_write_globals(const Input_objects*, const Stringpool*,
- const Stringpool*, Output_symtab_xindex*,
- Output_symtab_xindex*, Output_file*) const;
+ 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,
+ 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(const Input_objects*, Symbol*) const;
+ warn_about_undefined_dynobj_symbol(Symbol*) const;
// Write out a section symbol, specialized for size and endianness.
template<int size, bool big_endian>
sized_write_section_symbol(const Output_section*, Output_symtab_xindex*,
Output_file*, off_t) const;
- // The type of the symbol hash table.
-
- typedef std::pair<Stringpool::Key, Stringpool::Key> Symbol_table_key;
-
- struct Symbol_table_hash
- {
- size_t
- operator()(const Symbol_table_key&) const;
- };
-
- 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;
-
// The type of the list of symbols which have been forced local.
typedef std::vector<Symbol*> Forced_locals;
// We increment this every time we see a new undefined symbol, for
// use in archive groups.
- int saw_undefined_;
+ 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
// 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.
Copied_symbol_dynobjs copied_symbol_dynobjs_;
// Information parsed from the version script, if any.
const Version_script_info& version_script_;
+ Garbage_collection* gc_;
+ Icf* icf_;
};
// We inline get_sized_symbol for efficiency.
projects / deliverable / binutils-gdb.git / blobdiff