// layout.h -- lay out output file sections for gold -*- C++ -*-
-// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
#ifndef GOLD_LAYOUT_H
#define GOLD_LAYOUT_H
+#include <cstring>
#include <list>
#include <string>
#include <utility>
class General_options;
class Input_objects;
+class Mapfile;
class Symbol_table;
class Output_section_data;
class Output_section;
class Output_segment;
class Output_data;
class Output_data_dynamic;
+class Output_symtab_xindex;
+class Output_reduced_debug_abbrev_section;
+class Output_reduced_debug_info_section;
class Eh_frame;
class Target;
Layout_task_runner(const General_options& options,
const Input_objects* input_objects,
Symbol_table* symtab,
- Layout* layout)
+ Target* target,
+ Layout* layout,
+ Mapfile* mapfile)
: options_(options), input_objects_(input_objects), symtab_(symtab),
- layout_(layout)
+ target_(target), layout_(layout), mapfile_(mapfile)
{ }
// Run the operation.
const General_options& options_;
const Input_objects* input_objects_;
Symbol_table* symtab_;
+ Target* target_;
Layout* layout_;
+ Mapfile* mapfile_;
+};
+
+// This struct holds information about the comdat or .gnu.linkonce
+// that will be kept.
+
+struct Kept_section
+{
+ Kept_section()
+ : object(NULL), shndx(0), is_group(false), group_sections(NULL)
+ { }
+ Kept_section(Relobj* a_object, unsigned int a_shndx, bool a_is_group)
+ : object(a_object), shndx(a_shndx), is_group(a_is_group),
+ group_sections(NULL)
+ { }
+
+ typedef Unordered_map<std::string, unsigned int> Comdat_group;
+
+ // The object containing the comdat or .gnu.linkonce.
+ Relobj* object;
+ // Index to the group section for comdats and the section itself for
+ // .gnu.linkonce.
+ unsigned int shndx;
+ // The Kept_sections are values of a mapping, that maps names to
+ // them. This field is true if this struct is associated with the
+ // name of a comdat or .gnu.linkonce, false if it is associated with
+ // the name of a symbol obtained from the .gnu.linkonce.* name
+ // through some heuristics.
+ bool is_group;
+ // For comdats, a map from names of the sections in the group to
+ // indexes in OBJECT_. NULL for .gnu.linkonce.
+ Comdat_group* group_sections;
};
// This class handles the details of laying out input sections.
const char* group_section_name,
const char* signature,
const elfcpp::Shdr<size, big_endian>& shdr,
- const elfcpp::Elf_Word* contents);
+ elfcpp::Elf_Word flags,
+ std::vector<unsigned int>* shndxes);
// Like layout, only for exception frame sections. OBJECT is an
// object file. SYMBOLS is the contents of the symbol table
// Add an Output_section_data to the layout. This is used for
// special sections like the GOT section.
- void
+ Output_section*
add_output_section_data(const char* name, elfcpp::Elf_Word type,
elfcpp::Elf_Xword flags,
Output_section_data*);
void
define_section_symbols(Symbol_table*);
+ // Create sections for linker scripts.
+ void
+ create_script_sections()
+ { this->script_options_->create_script_sections(this); }
+
// Define symbols from any linker script.
void
define_script_symbols(Symbol_table* symtab)
dynpool() const
{ return &this->dynpool_; }
+ // Return the symtab_xindex section used to hold large section
+ // indexes for the normal symbol table.
+ Output_symtab_xindex*
+ symtab_xindex() const
+ { return this->symtab_xindex_; }
+
+ // Return the dynsym_xindex section used to hold large section
+ // indexes for the dynamic symbol table.
+ Output_symtab_xindex*
+ dynsym_xindex() const
+ { return this->dynsym_xindex_; }
+
// Return whether a section is a .gnu.linkonce section, given the
// section name.
static inline bool
is_linkonce(const char* name)
{ return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; }
- // Record the signature of a comdat section, and return whether to
- // include it in the link. The GROUP parameter is true for a
- // section group signature, false for a signature derived from a
- // .gnu.linkonce section.
+ // Return true if a section is a debugging section.
+ static inline bool
+ is_debug_info_section(const char* name)
+ {
+ // Debugging sections can only be recognized by name.
+ return (strncmp(name, ".debug", sizeof(".debug") - 1) == 0
+ || strncmp(name, ".gnu.linkonce.wi.",
+ sizeof(".gnu.linkonce.wi.") - 1) == 0
+ || strncmp(name, ".line", sizeof(".line") - 1) == 0
+ || strncmp(name, ".stab", sizeof(".stab") - 1) == 0);
+ }
+
+ // Check if a comdat group or .gnu.linkonce section with the given
+ // NAME is selected for the link. If there is already a section,
+ // *KEPT_SECTION is set to point to the signature and the function
+ // returns false. Otherwise, the CANDIDATE signature is recorded
+ // for this NAME in the layout object, *KEPT_SECTION is set to the
+ // internal copy and the function return false. In some cases, with
+ // CANDIDATE->GROUP_ being false, KEPT_SECTION can point back to
+ // CANDIDATE.
bool
- add_comdat(const char*, bool group);
+ find_or_add_kept_section(const std::string name,
+ Kept_section* candidate,
+ Kept_section** kept_section);
+
+ // Find the given comdat signature, and return the object and section
+ // index of the kept group.
+ Relobj*
+ find_kept_object(const std::string&, unsigned int*) const;
// Finalize the layout after all the input sections have been added.
off_t
- finalize(const Input_objects*, Symbol_table*, const Task*);
+ finalize(const Input_objects*, Symbol_table*, Target*, const Task*);
// Return whether any sections require postprocessing.
bool
script_options() const
{ return this->script_options_; }
+ // Compute and write out the build ID if needed.
+ void
+ write_build_id(Output_file*) const;
+
// Rewrite output file in binary format.
void
write_binary(Output_file* in) const;
+ // Print output sections to the map file.
+ void
+ print_to_mapfile(Mapfile*) const;
+
// Dump statistical information to stderr.
void
print_stats() const;
void
get_allocated_sections(Section_list*) const;
+ // Make a section for a linker script to hold data.
+ Output_section*
+ make_output_section_for_script(const char* name);
+
// Make a segment. This is used by the linker script code.
Output_segment*
make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags);
static elfcpp::Elf_Word
section_flags_to_segment(elfcpp::Elf_Xword flags);
+ // Attach sections to segments.
+ void
+ attach_sections_to_segments();
+
private:
Layout(const Layout&);
Layout& operator=(const Layout&);
};
typedef std::vector<Group_signature> Group_signatures;
- // Create a .note section for gold.
+ // Create a note section, filling in the header.
+ Output_section*
+ create_note(const char* name, int note_type, const char *section_name,
+ size_t descsz, bool allocate, size_t* trailing_padding);
+
+ // Create a note section for gold version.
void
create_gold_note();
void
create_executable_stack_info(const Target*);
+ // Create a build ID note if needed.
+ void
+ create_build_id();
+
// Find the first read-only PT_LOAD segment, creating one if
// necessary.
Output_segment*
// Create the output sections for the symbol table.
void
- create_symtab_sections(const Input_objects*, Symbol_table*, off_t*);
+ create_symtab_sections(const Input_objects*, Symbol_table*,
+ unsigned int, off_t*);
// Create the .shstrtab section.
Output_section*
// Create the section header table.
void
- create_shdrs(off_t*);
+ create_shdrs(const Output_section* shstrtab_section, off_t*);
// Create the dynamic symbol table.
void
const Symbol_table*,
unsigned int local_symcount,
const std::vector<Symbol*>& dynamic_symbols,
- const Output_section* dynstr
- ACCEPT_SIZE_ENDIAN);
+ const Output_section* dynstr);
// Return whether to include this section in the link.
template<int size, bool big_endian>
static const char*
linkonce_output_name(const char* name, size_t* plen);
+ // Return the number of allocated output sections.
+ size_t
+ allocated_output_section_count() const;
+
// Return the output section for NAME, TYPE and FLAGS.
Output_section*
get_output_section(const char* name, Stringpool::Key name_key,
Output_section*
choose_output_section(const Relobj* relobj, const char* name,
elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
- bool adjust_name);
+ bool is_input_section);
// Create a new Output_section.
Output_section*
make_output_section(const char* name, elfcpp::Elf_Word type,
elfcpp::Elf_Xword flags);
+ // Attach a section to a segment.
+ void
+ attach_section_to_segment(Output_section*);
+
+ // Attach an allocated section to a segment.
+ void
+ attach_allocated_section_to_segment(Output_section*);
+
// Set the final file offsets of all the segments.
off_t
set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx);
static bool
segment_precedes(const Output_segment* seg1, const Output_segment* seg2);
- // A mapping used for group signatures.
- typedef Unordered_map<std::string, bool> Signatures;
+ // A mapping used for kept comdats/.gnu.linkonce group signatures.
+ typedef Unordered_map<std::string, Kept_section> Signatures;
// Mapping from input section name/type/flags to output section. We
// use canonicalized strings here.
// The list of output sections which are not attached to any output
// segment.
Section_list unattached_section_list_;
+ // Whether we have attached the sections to the segments.
+ bool sections_are_attached_;
// The list of unattached Output_data objects which require special
// handling because they are not Output_sections.
Data_list special_output_list_;
Output_section_headers* section_headers_;
// A pointer to the PT_TLS segment if there is one.
Output_segment* tls_segment_;
+ // A pointer to the PT_GNU_RELRO segment if there is one.
+ Output_segment* relro_segment_;
// The SHT_SYMTAB output section.
Output_section* symtab_section_;
+ // The SHT_SYMTAB_SHNDX for the regular symbol table if there is one.
+ Output_symtab_xindex* symtab_xindex_;
// The SHT_DYNSYM output section if there is one.
Output_section* dynsym_section_;
+ // The SHT_SYMTAB_SHNDX for the dynamic symbol table if there is one.
+ Output_symtab_xindex* dynsym_xindex_;
// The SHT_DYNAMIC output section if there is one.
Output_section* dynamic_section_;
// The dynamic data which goes into dynamic_section_.
Output_section* eh_frame_section_;
// The exception frame data for eh_frame_section_.
Eh_frame* eh_frame_data_;
+ // Whether we have added eh_frame_data_ to the .eh_frame section.
+ bool added_eh_frame_data_;
// The exception frame header output section if there is one.
Output_section* eh_frame_hdr_section_;
+ // The space for the build ID checksum if there is one.
+ Output_section_data* build_id_note_;
+ // The output section containing dwarf abbreviations
+ Output_reduced_debug_abbrev_section* debug_abbrev_;
+ // The output section containing the dwarf debug info tree
+ Output_reduced_debug_info_section* debug_info_;
// A list of group sections and their signatures.
Group_signatures group_signatures_;
// The size of the output file.
class Write_symbols_task : public Task
{
public:
- Write_symbols_task(const Symbol_table* symtab,
+ Write_symbols_task(const Layout* layout, const Symbol_table* symtab,
const Input_objects* input_objects,
const Stringpool* sympool, const Stringpool* dynpool,
Output_file* of, Task_token* final_blocker)
- : symtab_(symtab), input_objects_(input_objects), sympool_(sympool),
- dynpool_(dynpool), of_(of), final_blocker_(final_blocker)
+ : layout_(layout), symtab_(symtab), input_objects_(input_objects),
+ sympool_(sympool), dynpool_(dynpool), of_(of),
+ final_blocker_(final_blocker)
{ }
// The standard Task methods.
{ return "Write_symbols_task"; }
private:
+ const Layout* layout_;
const Symbol_table* symtab_;
const Input_objects* input_objects_;
const Stringpool* sympool_;
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