// layout.h -- lay out output file sections for gold -*- C++ -*-
+// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
+// Written by Ian Lance Taylor <iant@google.com>.
+
+// This file is part of gold.
+
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+// MA 02110-1301, USA.
+
#ifndef GOLD_LAYOUT_H
#define GOLD_LAYOUT_H
#include <utility>
#include <vector>
-#include "options.h"
+#include "script.h"
#include "workqueue.h"
#include "object.h"
+#include "dynobj.h"
#include "stringpool.h"
namespace gold
{
+class General_options;
class Input_objects;
class Symbol_table;
+class Output_section_data;
class Output_section;
-class Output_section_symtab;
class Output_section_headers;
class Output_segment;
class Output_data;
+class Output_data_dynamic;
+class Eh_frame;
class Target;
// This task function handles mapping the input sections to output
// Run the operation.
void
- run(Workqueue*);
+ run(Workqueue*, const Task*);
private:
Layout_task_runner(const Layout_task_runner&);
class Layout
{
public:
- Layout(const General_options& options);
-
- // Given an input section named NAME with data in SHDR from the
- // object file OBJECT, return the output section where this input
- // section should go. Set *OFFSET to the offset within the output
- // section.
+ Layout(const General_options& options, Script_options*);
+
+ // Given an input section SHNDX, named NAME, with data in SHDR, from
+ // the object file OBJECT, return the output section where this
+ // input section should go. RELOC_SHNDX is the index of a
+ // relocation section which applies to this section, or 0 if none,
+ // or -1U if more than one. RELOC_TYPE is the type of the
+ // relocation section if there is one. Set *OFFSET to the offset
+ // within the output section.
+ template<int size, bool big_endian>
+ Output_section*
+ layout(Sized_relobj<size, big_endian> *object, unsigned int shndx,
+ const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
+ unsigned int reloc_shndx, unsigned int reloc_type, off_t* offset);
+
+ // Like layout, only for exception frame sections. OBJECT is an
+ // object file. SYMBOLS is the contents of the symbol table
+ // section, with size SYMBOLS_SIZE. SYMBOL_NAMES is the contents of
+ // the symbol name section, with size SYMBOL_NAMES_SIZE. SHNDX is a
+ // .eh_frame section in OBJECT. SHDR is the section header.
+ // RELOC_SHNDX is the index of a relocation section which applies to
+ // this section, or 0 if none, or -1U if more than one. RELOC_TYPE
+ // is the type of the relocation section if there is one. This
+ // returns the output section, and sets *OFFSET to the offset.
template<int size, bool big_endian>
Output_section*
- layout(Object *object, const char* name,
- const elfcpp::Shdr<size, big_endian>& shdr, off_t* offset);
+ layout_eh_frame(Sized_relobj<size, big_endian>* object,
+ const unsigned char* symbols,
+ off_t symbols_size,
+ const unsigned char* symbol_names,
+ off_t symbol_names_size,
+ unsigned int shndx,
+ const elfcpp::Shdr<size, big_endian>& shdr,
+ unsigned int reloc_shndx, unsigned int reloc_type,
+ off_t* offset);
+
+ // Handle a GNU stack note. This is called once per input object
+ // file. SEEN_GNU_STACK is true if the object file has a
+ // .note.GNU-stack section. GNU_STACK_FLAGS is the section flags
+ // from that section if there was one.
+ void
+ layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags);
+
+ // Add an Output_section_data to the layout. This is used for
+ // special sections like the GOT section.
+ void
+ add_output_section_data(const char* name, elfcpp::Elf_Word type,
+ elfcpp::Elf_Xword flags,
+ Output_section_data*);
+
+ // Create dynamic sections if necessary.
+ void
+ create_initial_dynamic_sections(Symbol_table*);
+
+ // Define __start and __stop symbols for output sections.
+ void
+ define_section_symbols(Symbol_table*);
+
+ // Define symbols from any linker script.
+ void
+ define_script_symbols(Symbol_table* symtab)
+ { this->script_options_->add_symbols_to_table(symtab); }
// Return the Stringpool used for symbol names.
const Stringpool*
sympool() const
{ return &this->sympool_; }
+ // Return the Stringpool used for dynamic symbol names and dynamic
+ // tags.
+ const Stringpool*
+ dynpool() const
+ { return &this->dynpool_; }
+
// Return whether a section is a .gnu.linkonce section, given the
// section name.
static inline bool
// Finalize the layout after all the input sections have been added.
off_t
- finalize(const Input_objects*, Symbol_table*);
+ finalize(const Input_objects*, Symbol_table*, const Task*);
- // Return the TLS segment.
+ // Return whether any sections require postprocessing.
+ bool
+ any_postprocessing_sections() const
+ { return this->any_postprocessing_sections_; }
+
+ // Return the size of the output file.
+ off_t
+ output_file_size() const
+ { return this->output_file_size_; }
+
+ // Return the TLS segment. This will return NULL if there isn't
+ // one.
Output_segment*
tls_segment() const
{ return this->tls_segment_; }
+ // Return the normal symbol table.
+ Output_section*
+ symtab_section() const
+ {
+ gold_assert(this->symtab_section_ != NULL);
+ return this->symtab_section_;
+ }
+
+ // Return the dynamic symbol table.
+ Output_section*
+ dynsym_section() const
+ {
+ gold_assert(this->dynsym_section_ != NULL);
+ return this->dynsym_section_;
+ }
+
+ // Return the dynamic tags.
+ Output_data_dynamic*
+ dynamic_data() const
+ { return this->dynamic_data_; }
+
+ // Write out the output sections.
+ void
+ write_output_sections(Output_file* of) const;
+
// Write out data not associated with an input file or the symbol
// table.
void
- write_data(Output_file*) const;
+ write_data(const Symbol_table*, Output_file*) const;
+
+ // Write out output sections which can not be written until all the
+ // input sections are complete.
+ void
+ write_sections_after_input_sections(Output_file* of);
+
+ // Return an output section named NAME, or NULL if there is none.
+ Output_section*
+ find_output_section(const char* name) const;
+
+ // Return an output segment of type TYPE, with segment flags SET set
+ // and segment flags CLEAR clear. Return NULL if there is none.
+ Output_segment*
+ find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set,
+ elfcpp::Elf_Word clear) const;
+
+ // Set a flag to indicate that an object file uses the static TLS model.
+ void
+ set_has_static_tls()
+ { this->has_static_tls_ = true; }
+
+ // Return true if any object file uses the static TLS model.
+ bool
+ has_static_tls() const
+ { return this->has_static_tls_; }
+
+ // Return the options which may be set by a linker script.
+ Script_options*
+ script_options()
+ { return this->script_options_; }
+
+ const Script_options*
+ script_options() const
+ { return this->script_options_; }
+
+ // Dump statistical information to stderr.
+ void
+ print_stats() const;
// The list of segments.
// The list of sections not attached to a segment.
- typedef std::list<Output_section*> Section_list;
+ typedef std::vector<Output_section*> Section_list;
// The list of information to write out which is not attached to
// either a section or a segment.
- typedef std::list<Output_data*> Data_list;
+ typedef std::vector<Output_data*> Data_list;
private:
Layout(const Layout&);
const char* from;
int fromlen;
const char* to;
+ int tolen;
};
static const Linkonce_mapping linkonce_mapping[];
static const int linkonce_mapping_count;
+ // Create a .note section for gold.
+ void
+ create_gold_note();
+
+ // Record whether the stack must be executable.
+ void
+ create_executable_stack_info(const Target*);
+
// Find the first read-only PT_LOAD segment, creating one if
// necessary.
Output_segment*
find_first_load_seg();
- // Set the final file offsets of all the segments.
- off_t
- set_segment_offsets(const Target*, Output_segment*);
-
- // Set the final file offsets of all the sections not associated
- // with a segment.
- off_t
- set_section_offsets(off_t);
+ // Count the local symbols in the regular symbol table and the dynamic
+ // symbol table, and build the respective string pools.
+ void
+ count_local_symbols(const Task*, const Input_objects*);
// Create the output sections for the symbol table.
void
- create_symtab_sections(int size, const Input_objects*, Symbol_table*, off_t*,
- Output_section** osymtab,
- Output_section** ostrtab);
+ create_symtab_sections(const Input_objects*, Symbol_table*, off_t*);
// Create the .shstrtab section.
Output_section*
create_shstrtab();
// Create the section header table.
- Output_section_headers*
- create_shdrs(int size, bool big_endian, off_t*);
+ void
+ create_shdrs(off_t*);
+
+ // Create the dynamic symbol table.
+ void
+ create_dynamic_symtab(const Input_objects*, Symbol_table*,
+ Output_section** pdynstr,
+ unsigned int* plocal_dynamic_count,
+ std::vector<Symbol*>* pdynamic_symbols,
+ Versions* versions);
+
+ // Assign offsets to each local portion of the dynamic symbol table.
+ void
+ assign_local_dynsym_offsets(const Input_objects*);
+
+ // Finish the .dynamic section and PT_DYNAMIC segment.
+ void
+ finish_dynamic_section(const Input_objects*, const Symbol_table*);
+
+ // Create the .interp section and PT_INTERP segment.
+ void
+ create_interp(const Target* target);
+
+ // Create the version sections.
+ void
+ create_version_sections(const Versions*,
+ const Symbol_table*,
+ unsigned int local_symcount,
+ const std::vector<Symbol*>& dynamic_symbols,
+ const Output_section* dynstr);
+
+ template<int size, bool big_endian>
+ void
+ sized_create_version_sections(const Versions* versions,
+ const Symbol_table*,
+ unsigned int local_symcount,
+ const std::vector<Symbol*>& dynamic_symbols,
+ const Output_section* dynstr
+ ACCEPT_SIZE_ENDIAN);
// Return whether to include this section in the link.
template<int size, bool big_endian>
bool
- include_section(Object* object, const char* name,
+ include_section(Sized_relobj<size, big_endian>* object, const char* name,
const elfcpp::Shdr<size, big_endian>&);
+ // Return the output section name to use given an input section
+ // name. Set *PLEN to the length of the name. *PLEN must be
+ // initialized to the length of NAME.
+ static const char*
+ output_section_name(const char* name, size_t* plen);
+
// Return the output section name to use for a linkonce section
- // name.
+ // name. PLEN is as for output_section_name.
static const char*
- linkonce_output_name(const char* name);
+ linkonce_output_name(const char* name, size_t* plen);
+
+ // Return the output section for NAME, TYPE and FLAGS.
+ Output_section*
+ get_output_section(const char* name, Stringpool::Key name_key,
+ elfcpp::Elf_Word type, elfcpp::Elf_Xword flags);
// Create a new Output_section.
Output_section*
make_output_section(const char* name, elfcpp::Elf_Word type,
elfcpp::Elf_Xword flags);
+ // Set the final file offsets of all the segments.
+ off_t
+ set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx);
+
+ // Set the final file offsets of all the sections not associated
+ // with a segment. We set section offsets in three passes: the
+ // first handles all allocated sections, the second sections that
+ // require postprocessing, and the last the late-bound STRTAB
+ // sections (probably only shstrtab, which is the one we care about
+ // because it holds section names).
+ enum Section_offset_pass
+ {
+ BEFORE_INPUT_SECTIONS_PASS,
+ POSTPROCESSING_SECTIONS_PASS,
+ STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
+ };
+ off_t
+ set_section_offsets(off_t, Section_offset_pass pass);
+
+ // Set the final section indexes of all the sections not associated
+ // with a segment. Returns the next unused index.
+ unsigned int
+ set_section_indexes(unsigned int pshndx);
+
// Return whether SEG1 comes before SEG2 in the output file.
static bool
segment_precedes(const Output_segment* seg1, const Output_segment* seg2);
// Mapping from input section name/type/flags to output section. We
// use canonicalized strings here.
- typedef std::pair<const char*,
+ typedef std::pair<Stringpool::Key,
std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key;
struct Hash_key
// A reference to the options on the command line.
const General_options& options_;
- // The index of the last output section.
- unsigned int last_shndx_;
+ // Information set by scripts or by command line options.
+ Script_options* script_options_;
// The output section names.
Stringpool namepool_;
// The output symbol names.
Stringpool sympool_;
+ // The dynamic strings, if needed.
+ Stringpool dynpool_;
// The list of group sections and linkonce sections which we have seen.
Signatures signatures_;
// The mapping from input section name/type/flags to output sections.
Section_name_map section_name_map_;
// The list of output segments.
Segment_list segment_list_;
+ // The list of output sections.
+ Section_list section_list_;
// The list of output sections which are not attached to any output
// segment.
- Section_list section_list_;
- // The list of sections which require special output because they
- // are not comprised of input sections.
+ Section_list unattached_section_list_;
+ // The list of unattached Output_data objects which require special
+ // handling because they are not Output_sections.
Data_list special_output_list_;
+ // The section headers.
+ Output_section_headers* section_headers_;
// A pointer to the PT_TLS segment if there is one.
Output_segment* tls_segment_;
+ // The SHT_SYMTAB output section.
+ Output_section* symtab_section_;
+ // The SHT_DYNSYM output section if there is one.
+ Output_section* dynsym_section_;
+ // The SHT_DYNAMIC output section if there is one.
+ Output_section* dynamic_section_;
+ // The dynamic data which goes into dynamic_section_.
+ Output_data_dynamic* dynamic_data_;
+ // The exception frame output section if there is one.
+ Output_section* eh_frame_section_;
+ // The exception frame data for eh_frame_section_.
+ Eh_frame* eh_frame_data_;
+ // The exception frame header output section if there is one.
+ Output_section* eh_frame_hdr_section_;
+ // The size of the output file.
+ off_t output_file_size_;
+ // Whether we have seen an object file marked to require an
+ // executable stack.
+ bool input_requires_executable_stack_;
+ // Whether we have seen at least one object file with an executable
+ // stack marker.
+ bool input_with_gnu_stack_note_;
+ // Whether we have seen at least one object file without an
+ // executable stack marker.
+ bool input_without_gnu_stack_note_;
+ // Whether we have seen an object file that uses the static TLS model.
+ bool has_static_tls_;
+ // Whether any sections require postprocessing.
+ bool any_postprocessing_sections_;
+};
+
+// This task handles writing out data in output sections which is not
+// part of an input section, or which requires special handling. When
+// this is done, it unblocks both output_sections_blocker and
+// final_blocker.
+
+class Write_sections_task : public Task
+{
+ public:
+ Write_sections_task(const Layout* layout, Output_file* of,
+ Task_token* output_sections_blocker,
+ Task_token* final_blocker)
+ : layout_(layout), of_(of),
+ output_sections_blocker_(output_sections_blocker),
+ final_blocker_(final_blocker)
+ { }
+
+ // The standard Task methods.
+
+ Task_token*
+ is_runnable();
+
+ void
+ locks(Task_locker*);
+
+ void
+ run(Workqueue*);
+
+ std::string
+ get_name() const
+ { return "Write_sections_task"; }
+
+ private:
+ class Write_sections_locker;
+
+ const Layout* layout_;
+ Output_file* of_;
+ Task_token* output_sections_blocker_;
+ Task_token* final_blocker_;
};
// This task handles writing out data which is not part of a section
class Write_data_task : public Task
{
public:
- Write_data_task(const Layout* layout, Output_file* of,
- Task_token* final_blocker)
- : layout_(layout), of_(of), final_blocker_(final_blocker)
+ Write_data_task(const Layout* layout, const Symbol_table* symtab,
+ Output_file* of, Task_token* final_blocker)
+ : layout_(layout), symtab_(symtab), of_(of), final_blocker_(final_blocker)
{ }
// The standard Task methods.
- Is_runnable_type
- is_runnable(Workqueue*);
+ Task_token*
+ is_runnable();
- Task_locker*
- locks(Workqueue*);
+ void
+ locks(Task_locker*);
void
run(Workqueue*);
+ std::string
+ get_name() const
+ { return "Write_data_task"; }
+
private:
const Layout* layout_;
+ const Symbol_table* symtab_;
Output_file* of_;
Task_token* final_blocker_;
};
class Write_symbols_task : public Task
{
public:
- Write_symbols_task(const Symbol_table* symtab, const Target* target,
- const Stringpool* sympool, Output_file* of,
- Task_token* final_blocker)
- : symtab_(symtab), target_(target), sympool_(sympool), of_(of),
- final_blocker_(final_blocker)
+ Write_symbols_task(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)
{ }
// The standard Task methods.
- Is_runnable_type
- is_runnable(Workqueue*);
+ Task_token*
+ is_runnable();
- Task_locker*
- locks(Workqueue*);
+ void
+ locks(Task_locker*);
void
run(Workqueue*);
+ std::string
+ get_name() const
+ { return "Write_symbols_task"; }
+
private:
const Symbol_table* symtab_;
- const Target* target_;
+ const Input_objects* input_objects_;
const Stringpool* sympool_;
+ const Stringpool* dynpool_;
Output_file* of_;
Task_token* final_blocker_;
};
+// This task handles writing out data in output sections which can't
+// be written out until all the input sections have been handled.
+// This is for sections whose contents is based on the contents of
+// other output sections.
+
+class Write_after_input_sections_task : public Task
+{
+ public:
+ Write_after_input_sections_task(Layout* layout, Output_file* of,
+ Task_token* input_sections_blocker,
+ Task_token* final_blocker)
+ : layout_(layout), of_(of),
+ input_sections_blocker_(input_sections_blocker),
+ final_blocker_(final_blocker)
+ { }
+
+ // The standard Task methods.
+
+ Task_token*
+ is_runnable();
+
+ void
+ locks(Task_locker*);
+
+ void
+ run(Workqueue*);
+
+ std::string
+ get_name() const
+ { return "Write_after_input_sections_task"; }
+
+ private:
+ Layout* layout_;
+ Output_file* of_;
+ Task_token* input_sections_blocker_;
+ Task_token* final_blocker_;
+};
+
// This task function handles closing the file.
class Close_task_runner : public Task_function_runner
// Run the operation.
void
- run(Workqueue*);
+ run(Workqueue*, const Task*);
private:
Output_file* of_;
};
+// A small helper function to align an address.
+
+inline uint64_t
+align_address(uint64_t address, uint64_t addralign)
+{
+ if (addralign != 0)
+ address = (address + addralign - 1) &~ (addralign - 1);
+ return address;
+}
+
} // End namespace gold.
#endif // !defined(GOLD_LAYOUT_H)
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