// symtab.h -- the gold symbol table -*- C++ -*-
-// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
+// Copyright (C) 2006-2020 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
class Object;
class Relobj;
template<int size, bool big_endian>
-class Sized_relobj;
+class Sized_relobj_file;
template<int size, bool big_endian>
class Sized_pluginobj;
class Dynobj;
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.
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.
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
object() const
{
gold_assert(this->source_ == FROM_OBJECT);
- return this->u_.from_object.object;
+ return this->u1_.object;
}
// Return the index of the section in the input relocatable or
{
gold_assert(this->source_ == FROM_OBJECT);
*is_ordinary = this->is_ordinary_shndx_;
- return this->u_.from_object.shndx;
+ return this->u2_.shndx;
}
// Return the output data section with which this symbol is
output_data() const
{
gold_assert(this->source_ == IN_OUTPUT_DATA);
- return this->u_.in_output_data.output_data;
+ return this->u1_.output_data;
}
// If this symbol was defined with respect to an output data
offset_is_from_end() const
{
gold_assert(this->source_ == IN_OUTPUT_DATA);
- return this->u_.in_output_data.offset_is_from_end;
+ return this->u2_.offset_is_from_end;
}
// Return the output segment with which this symbol is associated,
output_segment() const
{
gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
- return this->u_.in_output_segment.output_segment;
+ return this->u1_.output_segment;
}
// If this symbol was defined with respect to an output segment,
offset_base() const
{
gold_assert(this->source_ == IN_OUTPUT_SEGMENT);
- return this->u_.in_output_segment.offset_base;
+ return this->u2_.offset_base;
}
// Return the symbol binding.
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
override_visibility(elfcpp::STV);
// Set whether the symbol was originally a weak undef or a regular undef
- // when resolved by a dynamic def.
+ // when resolved by a dynamic def or by a special symbol.
inline void
set_undef_binding(elfcpp::STB bind)
{
}
}
- // Return TRUE if a weak undef was resolved by a dynamic def.
+ // 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_; }
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.
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
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.)
// Return whether this is a weak undefined symbol.
bool
is_weak_undefined() const
- { return this->is_undefined() && this->binding() == elfcpp::STB_WEAK; }
+ {
+ 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
{
if (this->source_ != FROM_OBJECT)
return false;
- if (this->type_ == elfcpp::STT_COMMON)
- return true;
bool is_ordinary;
unsigned int shndx = this->shndx(&is_ordinary);
return !is_ordinary && Symbol::is_common_shndx(shndx);
bool
is_externally_visible() const
{
- return (this->visibility_ == elfcpp::STV_DEFAULT
- || this->visibility_ == elfcpp::STV_PROTECTED);
+ 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
if (!parameters->options().shared())
return false;
- // If the user used -Bsymbolic, then nothing is preemptible.
+ // 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;
// A TLS-related reference.
TLS_REF = 4,
// A reference that can always be treated as a function call.
- FUNCTION_CALL = 8
+ 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
// A reference to any PLT entry in a non-position-independent executable
// does not need a dynamic relocation.
- if (!parameters->options().output_is_position_independent()
+ if (!(flags & FUNC_DESC_ABI)
+ && !parameters->options().output_is_position_independent()
&& this->has_plt_offset())
return false;
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
bool
may_need_copy_reloc() const
{
- return (!parameters->options().output_is_position_independent()
- && parameters->options().copyreloc()
+ 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(this, 0, sizeof *this); }
+ { memset(static_cast<void*>(this), 0, sizeof *this); }
// Initialize the general fields.
void
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);
+ unsigned char nonvis, bool offset_is_from_end,
+ bool is_predefined);
// Initialize fields for an Output_segment.
void
Output_segment* os, elfcpp::STT type,
elfcpp::STB binding, elfcpp::STV visibility,
unsigned char nonvis,
- Segment_offset_base offset_base);
+ 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);
+ unsigned char nonvis, bool is_predefined);
// Initialize fields for an undefined symbol.
void
union
{
- // This struct is used if SOURCE_ == FROM_OBJECT.
- struct
- {
- // Object in which symbol is defined, or in which it was first
- // seen.
- Object* object;
- // Section number in object_ in which symbol is defined.
- unsigned int shndx;
- } from_object;
-
- // This struct is used if SOURCE_ == IN_OUTPUT_DATA.
- struct
- {
- // Output_data in which symbol is defined. Before
- // Layout::finalize the symbol's value is an offset within the
- // Output_data.
- Output_data* output_data;
- // True if the offset is from the end, false if the offset is
- // from the beginning.
- bool offset_is_from_end;
- } in_output_data;
-
- // This struct is used if SOURCE_ == IN_OUTPUT_SEGMENT.
- struct
- {
- // Output_segment in which the symbol is defined. Before
- // Layout::finalize the symbol's value is an offset.
- Output_segment* output_segment;
- // The base to use for the offset before Layout::finalize.
- Segment_offset_base offset_base;
- } in_output_segment;
- } u_;
+ // 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
// non-zero value during Layout::finalize.
unsigned int dynsym_index_;
- // The GOT section entries for this symbol. A symbol may have more
- // than one GOT offset (e.g., when mixing modules compiled with two
- // different TLS models), but will usually have at most one.
- Got_offset_list got_offsets_;
-
// If this symbol has an entry in the PLT section, then this is the
// offset from the start of the PLT section. This is -1U if there
// is no PLT entry.
unsigned int plt_offset_;
+ // 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).
// True if this symbol was forced to local visibility by a version
// script (bit 28).
bool is_forced_local_ : 1;
- // True if the field u_.from_object.shndx is an ordinary section
+ // 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).
+ // 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).
// 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).
+ // 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
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 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);
+ 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);
+ unsigned char nonvis, bool is_predefined);
// Initialize fields for an undefined symbol.
void
- init_undefined(const char* name, const char* version, elfcpp::STT,
- elfcpp::STB, elfcpp::STV, unsigned char nonvis);
+ 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
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&);
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
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.
// Returns true if ICF determined that this is a duplicate section.
bool
- is_section_folded(Object* obj, unsigned int shndx) const;
+ is_section_folded(Relobj* obj, unsigned int shndx) const;
void
set_gc(Garbage_collection* gc)
void
gc_mark_undef_symbols(Layout*);
- // During garbage collection, this ensures externally visible symbols
- // are not treated as garbage while building shared objects.
+ // This tells garbage collection that this symbol is referenced.
void
- gc_mark_symbol_for_shlib(Symbol* sym);
+ gc_mark_symbol(Symbol* sym);
// During garbage collection, this keeps sections that correspond to
// symbols seen in dynamic objects.
// *DEFINED to the number of defined symbols.
template<int size, bool big_endian>
void
- add_from_relobj(Sized_relobj<size, big_endian>* relobj,
+ 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<size, big_endian>::Symbols*,
+ typename Sized_relobj_file<size, big_endian>::Symbols*,
size_t* defined);
// Add one external symbol from the plugin object OBJ to the symbol table.
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<size, big_endian>::Symbols*,
+ 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>
- Symbol*
+ Sized_symbol<size>*
add_from_incrobj(Object* obj, const char* name,
const char* ver, elfcpp::Sym<size, big_endian>* sym);
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.
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*);
get_copy_source(const Symbol* sym) const;
// Set the dynamic symbol indexes. INDEX is the index of the first
- // global dynamic symbol. Pointers to the symbols are stored into
+ // 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, std::vector<Symbol*>*,
- Stringpool*, Versions*);
+ 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,
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&);
typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
Symbol_table_eq> Symbol_table_type;
- // A map from symbol name (as a pointer into the namepool) to all
- // the locations the symbols is (weakly) defined (and certain other
- // conditions are met). This map will be used later to detect
- // possible One Definition Rule (ODR) violations.
- struct Symbol_location
- {
- Object* object; // Object where the symbol is defined.
- unsigned int shndx; // Section-in-object where the symbol is defined.
- off_t offset; // Offset-in-section where the symbol is defined.
- bool operator==(const Symbol_location& that) const
- {
- return (this->object == that.object
- && this->shndx == that.shndx
- && this->offset == that.offset);
- }
- };
-
- struct Symbol_location_hash
- {
- size_t operator()(const Symbol_location& loc) const
- { return reinterpret_cast<uintptr_t>(loc.object) ^ loc.offset ^ loc.shndx; }
- };
-
typedef Unordered_map<const char*,
Unordered_set<Symbol_location, Symbol_location_hash> >
Odr_map;
const elfcpp::Sym<size, big_endian>& sym,
unsigned int st_shndx, bool is_ordinary,
unsigned int orig_st_shndx,
- Object*, const char* version);
+ Object*, const char* version,
+ bool is_default_version);
template<int size, bool big_endian>
void
// Whether we should override a symbol, based on flags in
// resolve.cc.
static bool
- should_override(const Symbol*, unsigned int, Defined, Object*, bool*, bool*);
+ should_override(const Symbol*, unsigned int, elfcpp::STT, Defined,
+ Object*, bool*, bool*, bool);
// Report a problem in symbol resolution.
static void
// 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*, Defined);
+ should_override_with_special(const Symbol*, elfcpp::STT, 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* resolve_oldsym);
+ 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>
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.
+ // The index of the first global dynamic symbol (including
+ // forced-local symbols).
unsigned int first_dynamic_global_index_;
- // The number of global dynamic symbols, or 0 if none.
+ // 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.
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.
projects / deliverable / binutils-gdb.git / blobdiff