// inremental.h -- incremental linking support for gold -*- C++ -*-
-// Copyright 2009, 2010 Free Software Foundation, Inc.
+// Copyright (C) 2009-2020 Free Software Foundation, Inc.
// Written by Mikolaj Zalewski <mikolajz@google.com>.
// This file is part of gold.
class Incremental_inputs_checker;
class Incremental_script_entry;
class Incremental_object_entry;
+class Incremental_dynobj_entry;
class Incremental_archive_entry;
class Incremental_inputs;
class Incremental_binary;
class Incremental_library;
class Object;
-class Script_info;
// Incremental input type as stored in .gnu_incremental_inputs.
enum Incremental_input_flags
{
- INCREMENTAL_INPUT_IN_SYSTEM_DIR = 0x0800
+ INCREMENTAL_INPUT_IN_SYSTEM_DIR = 0x8000,
+ INCREMENTAL_INPUT_AS_NEEDED = 0x4000
};
+// Symbol flags for the incremental symbol table.
+// These flags are stored in the top two bits of
+// the symbol index field.
+
+enum Incremental_shlib_symbol_flags
+{
+ // Symbol is defined in this library.
+ INCREMENTAL_SHLIB_SYM_DEF = 2,
+ // Symbol is defined in this library, with a COPY relocation.
+ INCREMENTAL_SHLIB_SYM_COPY = 3
+};
+
+static const int INCREMENTAL_SHLIB_SYM_FLAGS_SHIFT = 30;
+
+// Return TRUE if a section of type SH_TYPE can be updated in place
+// during an incremental update.
+bool
+can_incremental_update(unsigned int sh_type);
+
// Create an Incremental_binary object for FILE. Returns NULL is this is not
// possible, e.g. FILE is not an ELF file or has an unsupported target.
Incremental_input_entry(Stringpool::Key filename_key, unsigned int arg_serial,
Timespec mtime)
: filename_key_(filename_key), file_index_(0), offset_(0), info_offset_(0),
- arg_serial_(arg_serial), mtime_(mtime), is_in_system_directory_(false)
+ arg_serial_(arg_serial), mtime_(mtime), is_in_system_directory_(false),
+ as_needed_(false)
{ }
virtual
is_in_system_directory() const
{ return this->is_in_system_directory_; }
+ // Record that the file was linked with --as-needed.
+ void
+ set_as_needed()
+ { this->as_needed_ = true; }
+
+ // Return TRUE if the file was linked with --as-needed.
+ bool
+ as_needed() const
+ { return this->as_needed_; }
+
// Return a pointer to the derived Incremental_script_entry object.
// Return NULL for input entries that are not script files.
Incremental_script_entry*
object_entry()
{ return this->do_object_entry(); }
+ // Return a pointer to the derived Incremental_dynobj_entry object.
+ // Return NULL for input entries that are not shared object files.
+ Incremental_dynobj_entry*
+ dynobj_entry()
+ { return this->do_dynobj_entry(); }
+
// Return a pointer to the derived Incremental_archive_entry object.
// Return NULL for input entries that are not archive files.
Incremental_archive_entry*
do_object_entry()
{ return NULL; }
+ // Return a pointer to the derived Incremental_dynobj_entry object.
+ // Return NULL for input entries that are not shared object files.
+ virtual Incremental_dynobj_entry*
+ do_dynobj_entry()
+ { return NULL; }
+
// Return a pointer to the derived Incremental_archive_entry object.
// Return NULL for input entries that are not archive files.
virtual Incremental_archive_entry*
// TRUE if the file was found in a system directory.
bool is_in_system_directory_;
+
+ // TRUE if the file was linked with --as-needed.
+ bool as_needed_;
};
// Information about a script input that will persist during the whole linker
{
public:
Script_info(const std::string& filename)
- : filename_(filename), incremental_script_entry_(NULL)
+ : filename_(filename), input_file_index_(0),
+ incremental_script_entry_(NULL)
+ { }
+
+ Script_info(const std::string& filename, unsigned int input_file_index)
+ : filename_(filename), input_file_index_(input_file_index),
+ incremental_script_entry_(NULL)
{ }
// Store a pointer to the incremental information for this script.
filename() const
{ return this->filename_; }
+ // Return the input file index.
+ unsigned int
+ input_file_index() const
+ { return this->input_file_index_; }
+
// Return the pointer to the incremental information for this script.
Incremental_script_entry*
incremental_info() const
private:
const std::string filename_;
+ unsigned int input_file_index_;
Incremental_script_entry* incremental_script_entry_;
};
{
public:
Incremental_script_entry(Stringpool::Key filename_key,
- unsigned int arg_serial, Script_info* script,
+ unsigned int arg_serial, Script_info* /*script*/,
Timespec mtime)
: Incremental_input_entry(filename_key, arg_serial, mtime),
- script_(script), objects_()
+ objects_()
{ }
// Add a member object to the archive.
{ return this; }
private:
- // Information about the script file.
- Script_info* script_;
// Objects that have been included by this script.
std::vector<Incremental_input_entry*> objects_;
};
Incremental_object_entry(Stringpool::Key filename_key, Object* obj,
unsigned int arg_serial, Timespec mtime)
: Incremental_input_entry(filename_key, arg_serial, mtime), obj_(obj),
- is_member_(false), sections_()
- {
- if (!obj_->is_dynamic())
- this->sections_.reserve(obj->shnum());
- }
+ is_member_(false), sections_(), groups_()
+ { this->sections_.reserve(obj->shnum()); }
// Get the object.
Object*
get_input_section_size(unsigned int n) const
{ return this->sections_[n].sh_size_; }
+ // Add a kept COMDAT group.
+ void
+ add_comdat_group(Stringpool::Key signature_key)
+ { this->groups_.push_back(signature_key); }
+
+ // Return the number of COMDAT groups.
+ unsigned int
+ get_comdat_group_count() const
+ { return this->groups_.size(); }
+
+ // Return the stringpool key for the signature of the Nth comdat group.
+ Stringpool::Key
+ get_comdat_signature_key(unsigned int n) const
+ { return this->groups_[n]; }
+
protected:
virtual Incremental_input_type
do_type() const
{
return (this->is_member_
? INCREMENTAL_INPUT_ARCHIVE_MEMBER
- : (this->obj_->is_dynamic()
- ? INCREMENTAL_INPUT_SHARED_LIBRARY
- : INCREMENTAL_INPUT_OBJECT));
+ : INCREMENTAL_INPUT_OBJECT);
}
// Return a pointer to the derived Incremental_object_entry object.
off_t sh_size_;
};
std::vector<Input_section> sections_;
+
+ // COMDAT groups.
+ std::vector<Stringpool::Key> groups_;
+};
+
+// Class for recording shared library input files.
+
+class Incremental_dynobj_entry : public Incremental_input_entry
+{
+ public:
+ Incremental_dynobj_entry(Stringpool::Key filename_key,
+ Stringpool::Key soname_key, Object* obj,
+ unsigned int arg_serial, Timespec mtime)
+ : Incremental_input_entry(filename_key, arg_serial, mtime),
+ soname_key_(soname_key), obj_(obj)
+ { }
+
+ // Get the object.
+ Object*
+ object() const
+ { return this->obj_; }
+
+ // Get the stringpool key for the soname.
+ Stringpool::Key
+ get_soname_key() const
+ { return this->soname_key_; }
+
+ protected:
+ virtual Incremental_input_type
+ do_type() const
+ { return INCREMENTAL_INPUT_SHARED_LIBRARY; }
+
+ // Return a pointer to the derived Incremental_dynobj_entry object.
+ virtual Incremental_dynobj_entry*
+ do_dynobj_entry()
+ { return this; }
+
+ private:
+ // Key of the soname string in the section stringtable.
+ Stringpool::Key soname_key_;
+
+ // The object file itself.
+ Object* obj_;
};
// Class for recording archive library input files.
report_input_section(Object* obj, unsigned int shndx, const char* name,
off_t sh_size);
+ // Record a kept COMDAT group belonging to object file OBJ.
+ void
+ report_comdat_group(Object* obj, const char* name);
+
// Record the info for input script SCRIPT.
void
report_script(Script_info* script, unsigned int arg_serial,
typedef elfcpp::Swap<64, big_endian> Swap64;
public:
+ // Size of the .gnu_incremental_inputs header.
+ // (3 x 4-byte fields, plus 4 bytes padding.)
+ static const unsigned int header_size = 16;
+ // Size of an input file entry.
+ // (2 x 4-byte fields, 1 x 12-byte field, 2 x 2-byte fields.)
+ static const unsigned int input_entry_size = 24;
+ // Size of the first part of the supplemental info block for
+ // relocatable objects and archive members.
+ // (7 x 4-byte fields, plus 4 bytes padding.)
+ static const unsigned int object_info_size = 32;
+ // Size of an input section entry.
+ // (2 x 4-byte fields, 2 x address-sized fields.)
+ static const unsigned int input_section_entry_size = 8 + 2 * size / 8;
+ // Size of a global symbol entry in the supplemental info block.
+ // (5 x 4-byte fields.)
+ static const unsigned int global_sym_entry_size = 20;
+
Incremental_inputs_reader()
: p_(NULL), strtab_(NULL, 0), input_file_count_(0)
{ }
// Reader class for an input file entry and its supplemental info.
class Incremental_input_entry_reader
{
+ private:
+ static const unsigned int object_info_size =
+ Incremental_inputs_reader<size, big_endian>::object_info_size;
+ static const unsigned int input_section_entry_size =
+ Incremental_inputs_reader<size, big_endian>::input_section_entry_size;
+ static const unsigned int global_sym_entry_size =
+ Incremental_inputs_reader<size, big_endian>::global_sym_entry_size;
+
public:
Incremental_input_entry_reader(const Incremental_inputs_reader* inputs,
unsigned int offset)
is_in_system_directory() const
{ return (this->flags_ & INCREMENTAL_INPUT_IN_SYSTEM_DIR) != 0; }
+ // Return TRUE if the file was linked with --as-needed.
+ bool
+ as_needed() const
+ { return (this->flags_ & INCREMENTAL_INPUT_AS_NEEDED) != 0; }
+
// Return the input section count -- for objects only.
unsigned int
get_input_section_count() const
return Swap32::readval(this->inputs_->p_ + this->info_offset_);
}
+ // Return the soname -- for shared libraries only.
+ const char*
+ get_soname() const
+ {
+ gold_assert(this->type() == INCREMENTAL_INPUT_SHARED_LIBRARY);
+ unsigned int offset = Swap32::readval(this->inputs_->p_
+ + this->info_offset_);
+ return this->inputs_->get_string(offset);
+ }
+
// Return the offset of the supplemental info for symbol SYMNDX --
// for objects only.
unsigned int
|| this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER);
unsigned int section_count = this->get_input_section_count();
- return (this->info_offset_ + 24
- + section_count * input_section_entry_size
- + symndx * 20);
+ return (this->info_offset_
+ + this->object_info_size
+ + section_count * this->input_section_entry_size
+ + symndx * this->global_sym_entry_size);
}
// Return the global symbol count -- for objects & shared libraries only.
unsigned int
get_global_symbol_count() const
{
- switch (this->type())
- {
- case INCREMENTAL_INPUT_OBJECT:
- case INCREMENTAL_INPUT_ARCHIVE_MEMBER:
- return Swap32::readval(this->inputs_->p_ + this->info_offset_ + 4);
- case INCREMENTAL_INPUT_SHARED_LIBRARY:
- return Swap32::readval(this->inputs_->p_ + this->info_offset_);
- default:
- gold_unreachable();
- }
+ gold_assert(this->type() == INCREMENTAL_INPUT_OBJECT
+ || this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER
+ || this->type() == INCREMENTAL_INPUT_SHARED_LIBRARY);
+ return Swap32::readval(this->inputs_->p_ + this->info_offset_ + 4);
}
// Return the offset of the first local symbol -- for objects only.
return Swap32::readval(this->inputs_->p_ + this->info_offset_ + 20);
}
+ // Return the COMDAT group count -- for objects only.
+ unsigned int
+ get_comdat_group_count() const
+ {
+ gold_assert(this->type() == INCREMENTAL_INPUT_OBJECT
+ || this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER);
+
+ return Swap32::readval(this->inputs_->p_ + this->info_offset_ + 24);
+ }
+
// Return the object count -- for scripts only.
unsigned int
get_object_count() const
{
Input_section_info info;
const unsigned char* p = (this->inputs_->p_
- + this->info_offset_ + 24
- + n * input_section_entry_size);
+ + this->info_offset_
+ + this->object_info_size
+ + n * this->input_section_entry_size);
unsigned int name_offset = Swap32::readval(p);
info.name = this->inputs_->get_string(name_offset);
info.output_shndx = Swap32::readval(p + 4);
|| this->type() == INCREMENTAL_INPUT_ARCHIVE_MEMBER);
unsigned int section_count = this->get_input_section_count();
const unsigned char* p = (this->inputs_->p_
- + this->info_offset_ + 24
- + section_count * input_section_entry_size
- + n * 20);
+ + this->info_offset_
+ + this->object_info_size
+ + section_count * this->input_section_entry_size
+ + n * this->global_sym_entry_size);
return Incremental_global_symbol_reader<big_endian>(p);
}
+ // Return the signature of the Nth comdat group -- for objects only.
+ const char*
+ get_comdat_group_signature(unsigned int n) const
+ {
+ unsigned int section_count = this->get_input_section_count();
+ unsigned int symbol_count = this->get_global_symbol_count();
+ const unsigned char* p = (this->inputs_->p_
+ + this->info_offset_
+ + this->object_info_size
+ + section_count * this->input_section_entry_size
+ + symbol_count * this->global_sym_entry_size
+ + n * 4);
+ unsigned int name_offset = Swap32::readval(p);
+ return this->inputs_->get_string(name_offset);
+ }
+
// Return the output symbol index for the Nth global symbol -- for shared
// libraries only. Sets *IS_DEF to TRUE if the symbol is defined in this
- // input file.
+ // input file. Sets *IS_COPY to TRUE if the symbol was copied from this
+ // input file with a COPY relocation.
unsigned int
- get_output_symbol_index(unsigned int n, bool* is_def)
+ get_output_symbol_index(unsigned int n, bool* is_def, bool* is_copy)
{
gold_assert(this->type() == INCREMENTAL_INPUT_SHARED_LIBRARY);
const unsigned char* p = (this->inputs_->p_
- + this->info_offset_ + 4
+ + this->info_offset_ + 8
+ n * 4);
unsigned int output_symndx = Swap32::readval(p);
- *is_def = (output_symndx & (1U << 31)) != 0;
- return output_symndx & ((1U << 31) - 1);
+ unsigned int flags = output_symndx >> INCREMENTAL_SHLIB_SYM_FLAGS_SHIFT;
+ output_symndx &= ((1U << INCREMENTAL_SHLIB_SYM_FLAGS_SHIFT) - 1);
+ switch (flags)
+ {
+ case INCREMENTAL_SHLIB_SYM_DEF:
+ *is_def = true;
+ *is_copy = false;
+ break;
+ case INCREMENTAL_SHLIB_SYM_COPY:
+ *is_def = true;
+ *is_copy = true;
+ break;
+ default:
+ *is_def = false;
+ *is_copy = false;
+ }
+ return output_symndx;
}
private:
- // Size of an input section entry.
- static const unsigned int input_section_entry_size = 8 + 2 * size / 8;
// The reader instance for the containing section.
const Incremental_inputs_reader* inputs_;
// The flags, including the type of input file.
input_file_offset(unsigned int n) const
{
gold_assert(n < this->input_file_count_);
- return 16 + n * 24;
+ return this->header_size + n * this->input_entry_size;
}
// Return the index of an input file entry given its OFFSET.
unsigned int
input_file_index(unsigned int offset) const
{
- int n = (offset - 16) / 24;
+ int n = ((offset - this->header_size) / this->input_entry_size);
gold_assert(input_file_offset(n) == offset);
return n;
}
Incremental_input_entry_reader
input_file_at_offset(unsigned int offset) const
{
- gold_assert(offset < 16 + this->input_file_count_ * 24);
+ gold_assert(offset < (this->header_size
+ + this->input_file_count_ * this->input_entry_size));
return Incremental_input_entry_reader(this, offset);
}
class Incremental_binary
{
public:
- Incremental_binary(Output_file* output, Target* target)
+ Incremental_binary(Output_file* output, Target* /*target*/)
: input_args_map_(), library_map_(), script_map_(),
- output_(output), target_(target)
+ output_(output)
{ }
virtual
Input_reader()
{ }
+ Input_reader(const Input_reader&)
+ { }
+
virtual
~Input_reader()
{ }
// Return an Incremental_library for the given input file.
Incremental_library*
- get_library(unsigned int n)
+ get_library(unsigned int n) const
{ return this->library_map_[n]; }
// Return a Script_info for the given input file.
Script_info*
- get_script_info(unsigned int n)
+ get_script_info(unsigned int n) const
{ return this->script_map_[n]; }
// Initialize the layout of the output file based on the existing
process_got_plt(Symbol_table* symtab, Layout* layout)
{ this->do_process_got_plt(symtab, layout); }
+ // Emit COPY relocations from the existing output file.
+ void
+ emit_copy_relocs(Symbol_table* symtab)
+ { this->do_emit_copy_relocs(symtab); }
+
// Apply incremental relocations for symbols whose values have changed.
void
apply_incremental_relocs(const Symbol_table* symtab, Layout* layout,
virtual void
do_process_got_plt(Symbol_table* symtab, Layout* layout) = 0;
+ // Emit COPY relocations from the existing output file.
+ virtual void
+ do_emit_copy_relocs(Symbol_table* symtab) = 0;
+
// Apply incremental relocations for symbols whose values have changed.
virtual void
do_apply_incremental_relocs(const Symbol_table*, Layout*, Output_file*) = 0;
private:
// Edited output file object.
Output_file* output_;
- // Target of the output file.
- Target* target_;
};
template<int size, bool big_endian>
const elfcpp::Ehdr<size, big_endian>& ehdr,
Target* target)
: Incremental_binary(output, target), elf_file_(this, ehdr),
- input_objects_(), section_map_(), symbol_map_(), main_symtab_loc_(),
- main_strtab_loc_(), has_incremental_info_(false), inputs_reader_(),
- symtab_reader_(), relocs_reader_(), got_plt_reader_(),
+ input_objects_(), section_map_(), symbol_map_(), copy_relocs_(),
+ main_symtab_loc_(), main_strtab_loc_(), has_incremental_info_(false),
+ inputs_reader_(), symtab_reader_(), relocs_reader_(), got_plt_reader_(),
input_entry_readers_()
{ this->setup_readers(); }
global_symbol(unsigned int symndx) const
{ return this->symbol_map_[symndx]; }
+ // Add a COPY relocation for a global symbol.
+ void
+ add_copy_reloc(Symbol* gsym, Output_section* os, off_t offset)
+ { this->copy_relocs_.push_back(Copy_reloc(gsym, os, offset)); }
+
// Readers for the incremental info sections.
const Incremental_inputs_reader<size, big_endian>&
virtual void
do_process_got_plt(Symbol_table* symtab, Layout* layout);
+ // Emit COPY relocations from the existing output file.
+ virtual void
+ do_emit_copy_relocs(Symbol_table* symtab);
+
// Apply incremental relocations for symbols whose values have changed.
virtual void
do_apply_incremental_relocs(const Symbol_table* symtab, Layout* layout,
: Input_reader(), reader_(r)
{ }
+ Sized_input_reader(const Sized_input_reader& r)
+ : Input_reader(), reader_(r.reader_)
+ { }
+
virtual
~Sized_input_reader()
{ }
}
private:
+ // List of symbols that need COPY relocations.
+ struct Copy_reloc
+ {
+ Copy_reloc(Symbol* sym, Output_section* os, off_t off)
+ : symbol(sym), output_section(os), offset(off)
+ { }
+
+ // The global symbol to copy.
+ Symbol* symbol;
+ // The output section into which the symbol was copied.
+ Output_section* output_section;
+ // The offset within that output section.
+ off_t offset;
+ };
+ typedef std::vector<Copy_reloc> Copy_relocs;
+
bool
find_incremental_inputs_sections(unsigned int* p_inputs_shndx,
unsigned int* p_symtab_shndx,
// Map global symbols from the input file to the symbol table.
std::vector<Symbol*> symbol_map_;
+ // List of symbols that need COPY relocations.
+ Copy_relocs copy_relocs_;
+
// Locations of the main symbol table and symbol string table.
Location main_symtab_loc_;
Location main_strtab_loc_;
// Get the name of a section.
std::string
- do_section_name(unsigned int shndx);
+ do_section_name(unsigned int shndx) const;
// Return a view of the contents of a section.
- Object::Location
- do_section_contents(unsigned int shndx);
+ const unsigned char*
+ do_section_contents(unsigned int shndx, section_size_type* plen,
+ bool cache);
// Return section flags.
uint64_t
do_get_global_symbols() const
{ return &this->symbols_; }
+ // Return the value of a local symbol.
+ uint64_t
+ do_local_symbol_value(unsigned int, uint64_t) const
+ { gold_unreachable(); }
+
+ unsigned int
+ do_local_plt_offset(unsigned int) const
+ { gold_unreachable(); }
+
+ bool
+ do_local_is_tls(unsigned int) const
+ { gold_unreachable(); }
+
// Return the number of local symbols.
unsigned int
do_local_symbol_count() const
unsigned int local_dynsym_offset_;
// The entries in the symbol table for the external symbols.
Symbols symbols_;
+ // Number of symbols defined in object file itself.
+ size_t defined_count_;
// The offset of the first incremental relocation for this object.
unsigned int incr_reloc_offset_;
// The number of incremental relocations for this object.
// Get the name of a section.
std::string
- do_section_name(unsigned int shndx);
+ do_section_name(unsigned int shndx) const;
// Return a view of the contents of a section.
- Object::Location
- do_section_contents(unsigned int shndx);
+ const unsigned char*
+ do_section_contents(unsigned int shndx, section_size_type* plen,
+ bool cache);
// Return section flags.
uint64_t
Input_entry_reader input_reader_;
// The entries in the symbol table for the external symbols.
Symbols symbols_;
+ // Number of symbols defined in object file itself.
+ size_t defined_count_;
};
// Allocate an incremental object of the appropriate size and endianness.
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