#include <string>
#include <utility>
+#include <vector>
#include <cassert>
#include "elfcpp.h"
{
class Object;
+class Output_data;
+class Output_segment;
class Output_file;
class Target;
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 an 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.
+ CONSTANT
+ };
+
+ // 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
version() const
{ return this->version_; }
+ // 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_; }
+ {
+ assert(this->source_ == FROM_OBJECT);
+ return this->u_.from_object.object;
+ }
+
+ // Return the index of the section in the input object file.
+ unsigned int
+ shnum() const
+ {
+ assert(this->source_ == FROM_OBJECT);
+ return this->u_.from_object.shnum;
+ }
+
+ // 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
+ {
+ assert(this->source_ == IN_OUTPUT_DATA);
+ return this->u_.in_output_data.output_data;
+ }
+
+ // If this symbol was defined with respect to an output data
+ // section, return whether the value is an offset from end.
+ bool
+ offset_is_from_end() const
+ {
+ assert(this->source_ == IN_OUTPUT_DATA);
+ return this->u_.in_output_data.offset_is_from_end;
+ }
+
+ // Return the output segment with which this symbol is associated,
+ // if the symbol was specially defined with respect to an output
+ // segment.
+ Output_segment*
+ output_segment() const
+ {
+ assert(this->source_ == IN_OUTPUT_SEGMENT);
+ return this->u_.in_output_segment.output_segment;
+ }
+
+ // If this symbol was defined with respect to an output segment,
+ // return the offset base.
+ Segment_offset_base
+ offset_base() const
+ {
+ assert(this->source_ == IN_OUTPUT_SEGMENT);
+ return this->u_.in_output_segment.offset_base;
+ }
// Return the symbol binding.
elfcpp::STB
// Return the non-visibility part of the st_other field.
unsigned char
- other() const
- { return this->other_; }
-
- // Return the section index.
- unsigned int
- shnum() const
- { return this->shnum_; }
+ nonvis() const
+ { return this->nonvis_; }
// Return whether this symbol is a forwarder. This will never be
// true of a symbol found in the hash table, but may be true of
set_in_dyn()
{ this->in_dyn_ = true; }
+ // Return whether this symbol has an entry in the GOT section.
+ bool
+ has_got_offset() const
+ { return this->has_got_offset_; }
+
+ // Return the offset into the GOT section of this symbol.
+ unsigned int
+ got_offset() const
+ {
+ assert(this->has_got_offset());
+ return this->got_offset_;
+ }
+
+ // Set the GOT offset of this symbol.
+ void
+ set_got_offset(unsigned int got_offset)
+ {
+ this->has_got_offset_ = true;
+ this->got_offset_ = got_offset;
+ }
+
+ // Return whether this symbol is resolved locally. This is always
+ // true when linking statically. It is true for a symbol defined in
+ // this object when using -Bsymbolic. It is true for a symbol
+ // marked local in a version file. FIXME: This needs to be
+ // completed.
+ bool
+ is_resolved_locally() const
+ { return !this->in_dyn_; }
+
+ // Return whether this is an undefined symbol.
+ bool
+ is_undefined() const
+ {
+ return this->source_ == FROM_OBJECT && this->shnum() == elfcpp::SHN_UNDEF;
+ }
+
+ // Return whether this is a common symbol.
+ bool
+ is_common() const
+ {
+ return this->source_ == FROM_OBJECT && this->shnum() == elfcpp::SHN_COMMON;
+ }
+
protected:
// Instances of this class should always be created at a specific
// size.
Symbol()
{ }
+ // 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.
template<int size, bool big_endian>
void
init_base(const char *name, const char* version, Object* object,
const elfcpp::Sym<size, big_endian>&);
+ // Initialize fields for an Output_data.
+ void
+ init_base(const char* name, Output_data*, elfcpp::STT, elfcpp::STB,
+ elfcpp::STV, unsigned char nonvis, bool offset_is_from_end);
+
+ // Initialize fields for an Output_segment.
+ void
+ init_base(const char* name, Output_segment* os, elfcpp::STT type,
+ elfcpp::STB binding, elfcpp::STV visibility,
+ unsigned char nonvis, Segment_offset_base offset_base);
+
+ // Initialize fields for a constant.
+ void
+ init_base(const char* name, elfcpp::STT type, elfcpp::STB binding,
+ elfcpp::STV visibility, unsigned char nonvis);
+
// Override existing symbol.
template<int size, bool big_endian>
void
// 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_;
+
+ 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 shnum;
+ } 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_;
+
+ // If this symbol has an entry in the GOT section (has_got_offset_
+ // is true), this is the offset.
+ unsigned int got_offset_;
// Symbol type.
elfcpp::STT type_ : 4;
// Symbol binding.
// Symbol visibility.
elfcpp::STV visibility_ : 2;
// Rest of symbol st_other field.
- unsigned int other_ : 6;
+ unsigned int nonvis_ : 6;
+ // The type of symbol.
+ Source source_ : 2;
// True if this symbol always requires special target-specific
// handling.
- bool is_special_ : 1;
+ bool is_target_special_ : 1;
// True if this is the default version of the symbol.
bool is_def_ : 1;
// True if this symbol really forwards to another symbol. This is
bool is_forwarder_ : 1;
// True if we've seen this symbol in a dynamic object.
bool in_dyn_ : 1;
+ // True if the symbol has an entry in the GOT section.
+ bool has_got_offset_ : 1;
};
// The parts of a symbol which are size specific. Using a template
init(const char *name, const char* version, Object* object,
const elfcpp::Sym<size, big_endian>&);
+ // Initialize fields for an Output_data.
+ void
+ init(const char* name, Output_data*, Value_type value, Size_type symsize,
+ elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis,
+ bool offset_is_from_end);
+
+ // Initialize fields for an Output_segment.
+ void
+ init(const char* name, Output_segment*, Value_type value, Size_type symsize,
+ elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis,
+ Segment_offset_base offset_base);
+
+ // Initialize fields for a constant.
+ void
+ init(const char* name, Value_type value, Size_type symsize,
+ elfcpp::STT, elfcpp::STB, elfcpp::STV, unsigned char nonvis);
+
// Override existing symbol.
template<bool big_endian>
void
// 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.
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;
};
// The main linker symbol table.
size_t count, const char* sym_names, size_t sym_name_size,
Symbol** sympointers);
+ // Define a special symbol.
+ template<int size, bool big_endian>
+ Sized_symbol<size>*
+ define_special_symbol(Target* target, const char* name, bool only_if_ref
+ ACCEPT_SIZE_ENDIAN);
+
+ // Define a special symbol based on an Output_data. It is a
+ // multiple definition error if this symbol is already defined.
+ void
+ define_in_output_data(Target*, const char* name, 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.
+ void
+ define_in_output_segment(Target*, const char* name, 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.
+ void
+ define_as_constant(Target*, const char* name, uint64_t value,
+ uint64_t symsize, elfcpp::STT type, elfcpp::STB binding,
+ elfcpp::STV visibility, unsigned char nonvis,
+ bool only_if_ref);
+
+ // Define a set of symbols in output sections.
+ void
+ define_symbols(const Layout*, Target*, int count,
+ const Define_symbol_in_section*);
+
+ // Define a set of symbols in output segments.
+ void
+ define_symbols(const Layout*, Target*, int count,
+ const Define_symbol_in_segment*);
+
// Look up a symbol.
Symbol*
lookup(const char*, const char* version = NULL) const;
const Sized_symbol<size>*
get_sized_symbol(const Symbol* ACCEPT_SIZE) const;
+ // Return the count of undefined symbols seen.
+ int
+ saw_undefined() const
+ { return this->saw_undefined_; }
+
+ // Allocate the common symbols
+ void
+ allocate_commons(const General_options&, Layout*);
+
// 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
resolve(Sized_symbol<size>* to, const Sized_symbol<size>* from
ACCEPT_SIZE_ENDIAN);
+ // Define a symbol in an Output_data, sized version.
+ template<int size>
+ void
+ do_define_in_output_data(Target*, const char* name, 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>
+ void
+ do_define_in_output_segment(
+ Target*, const char* name, 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>
+ void
+ do_define_as_constant(
+ Target*, const char* name,
+ 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);
+
+ // Allocate the common symbols, sized version.
+ template<int size>
+ void
+ do_allocate_commons(const General_options&, Layout*);
+
// Finalize symbols specialized for size.
template<int size>
off_t
typedef Unordered_map<Symbol_table_key, Symbol*, Symbol_table_hash,
Symbol_table_eq> Symbol_table_type;
+ // The type of the list of common symbols.
+
+ typedef std::vector<Symbol*> Commons_type;
+
// The size of the symbols in the symbol table (32 or 64).
int size_;
+ // We increment this every time we see a new undefined symbol, for
+ // use in archive groups.
+ int saw_undefined_;
+
// The file offset within the output symtab section where we should
// write the table.
off_t offset_;
// Forwarding symbols.
Unordered_map<Symbol*, Symbol*> forwarders_;
+
+ // 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_;
};
// We inline get_sized_symbol for efficiency.
projects / deliverable / binutils-gdb.git / blobdiff