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// script-sections.h -- linker script SECTIONS for gold -*- C++ -*-
// Copyright (C) 2008-2024 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.
// This is for the support of the SECTIONS clause in linker scripts.
#ifndef GOLD_SCRIPT_SECTIONS_H
#define GOLD_SCRIPT_SECTIONS_H
#include <cstdio>
#include <list>
#include <vector>
namespace gold
{
struct Parser_output_section_header;
struct Parser_output_section_trailer;
struct Input_section_spec;
class Expression;
class Sections_element;
class Memory_region;
class Phdrs_element;
class Output_data;
class Output_section_definition;
class Output_section;
class Output_segment;
class Orphan_section_placement;
class Script_sections
{
public:
// This is a list, not a vector, because we insert orphan sections
// in the middle.
typedef std::list<Sections_element*> Sections_elements;
// Logical script section types. We map section types returned by the
// parser into these since some section types have the same semantics.
enum Section_type
{
// No section type specified.
ST_NONE,
// Section is NOLOAD. We allocate space in the output but section
// is not loaded in runtime.
ST_NOLOAD,
// No space is allocated to section.
ST_NOALLOC
};
Script_sections();
// Start a SECTIONS clause.
void
start_sections();
// Finish a SECTIONS clause.
void
finish_sections();
// Return whether we ever saw a SECTIONS clause. If we did, then
// all section layout needs to go through this class.
bool
saw_sections_clause() const
{ return this->saw_sections_clause_; }
// Return whether we are currently processing a SECTIONS clause.
bool
in_sections_clause() const
{ return this->in_sections_clause_; }
// Return whether we ever saw a PHDRS clause. We ignore the PHDRS
// clause unless we also saw a SECTIONS clause.
bool
saw_phdrs_clause() const
{ return this->saw_sections_clause_ && this->phdrs_elements_ != NULL; }
// Start processing entries for an output section.
void
start_output_section(const char* name, size_t namelen,
const Parser_output_section_header*);
// Finish processing entries for an output section.
void
finish_output_section(const Parser_output_section_trailer*);
// Add a data item to the current output section.
void
add_data(int size, bool is_signed, Expression* val);
// Add a symbol to be defined.
void
add_symbol_assignment(const char* name, size_t length, Expression* value,
bool provide, bool hidden);
// Add an assignment to the special dot symbol.
void
add_dot_assignment(Expression* value);
// Add an assertion.
void
add_assertion(Expression* check, const char* message, size_t messagelen);
// Add a setting for the fill value.
void
add_fill(Expression* val);
// Add an input section specification.
void
add_input_section(const Input_section_spec* spec, bool keep);
// Saw DATA_SEGMENT_ALIGN.
void
data_segment_align();
// Saw DATA_SEGMENT_RELRO_END.
void
data_segment_relro_end();
// Create any required sections.
void
create_sections(Layout*);
// Add any symbols we are defining to the symbol table.
void
add_symbols_to_table(Symbol_table*);
// Finalize symbol values and check assertions.
void
finalize_symbols(Symbol_table* symtab, const Layout* layout);
// Find the name of the output section to use for an input file name
// and section name. This returns a name, and sets
// *OUTPUT_SECTION_SLOT to point to the address where the actual
// output section may be stored.
// 1) If the input section should be discarded, this returns NULL
// and sets *OUTPUT_SECTION_SLOT to NULL.
// 2) If the input section is mapped by the SECTIONS clause, this
// returns the name to use for the output section (in permanent
// storage), and sets *OUTPUT_SECTION_SLOT to point to where the
// output section should be stored. **OUTPUT_SECTION_SLOT will be
// non-NULL if we have seen this output section already.
// 3) If the input section is not mapped by the SECTIONS clause,
// this returns SECTION_NAME, and sets *OUTPUT_SECTION_SLOT to
// NULL.
// PSCRIPT_SECTION_TYPE points to a location for returning the section
// type specified in script. This can be SCRIPT_SECTION_TYPE_NONE if
// no type is specified.
// *KEEP indicates whether the section should survive garbage collection.
// MATCH_INPUT_SPEC indicates whether the section should be matched
// with input section specs or simply against the output section name
// (i.e., for linker-created sections like .dynamic).
const char*
output_section_name(const char* file_name, const char* section_name,
Output_section*** output_section_slot,
Section_type* pscript_section_type,
bool* keep, bool match_input_spec);
// Place a marker for an orphan output section into the SECTIONS
// clause.
void
place_orphan(Output_section* os);
// Set the addresses of all the output sections. Return the segment
// which holds the file header and segment headers, if any.
Output_segment*
set_section_addresses(Symbol_table*, Layout*);
// Add a program header definition.
void
add_phdr(const char* name, size_t namelen, unsigned int type,
bool filehdr, bool phdrs, bool is_flags_valid, unsigned int flags,
Expression* load_address);
// Return the number of segments we expect to create based on the
// SECTIONS clause.
size_t
expected_segment_count(const Layout*) const;
// Add the file header and segment header to non-load segments as
// specified by the PHDRS clause.
void
put_headers_in_phdrs(Output_data* file_header, Output_data* segment_headers);
// Look for an output section by name and return the address, the
// load address, the alignment, and the size. This is used when an
// expression refers to an output section which was not actually
// created. This returns true if the section was found, false
// otherwise.
bool
get_output_section_info(const char* name, uint64_t* address,
uint64_t* load_address, uint64_t* addralign,
uint64_t* size) const;
// Release all Output_segments. This is used in relaxation.
void
release_segments();
// Whether we ever saw a SEGMENT_START expression, the presence of which
// changes the behaviour of -Ttext, -Tdata and -Tbss options.
bool
saw_segment_start_expression() const
{ return this->saw_segment_start_expression_; }
// Set the flag which indicates whether we saw a SEGMENT_START expression.
void
set_saw_segment_start_expression(bool value)
{ this->saw_segment_start_expression_ = value; }
// Add a memory region.
void
add_memory_region(const char*, size_t, unsigned int,
Expression*, Expression*);
// Find a memory region's origin.
Expression*
find_memory_region_origin(const char*, size_t);
// Find a memory region's length.
Expression*
find_memory_region_length(const char*, size_t);
// Find a memory region by name.
Memory_region*
find_memory_region(const char*, size_t);
// Find a memory region that should be used by a given output section.
Memory_region*
find_memory_region(Output_section_definition*, bool, bool,
Output_section_definition**);
// Returns true if the provide block of memory is contained
// within a memory region.
bool
block_in_region(Symbol_table*, Layout*, uint64_t, uint64_t) const;
// Set the memory region of the section.
void
set_memory_region(Memory_region*, bool);
// Print the contents to the FILE. This is for debugging.
void
print(FILE*) const;
// Used for orphan sections.
typedef Sections_elements::iterator Elements_iterator;
private:
typedef std::vector<Memory_region*> Memory_regions;
typedef std::vector<Phdrs_element*> Phdrs_elements;
// Create segments.
Output_segment*
create_segments(Layout*, uint64_t);
// Create PT_NOTE and PT_TLS segments.
void
create_note_and_tls_segments(Layout*, const std::vector<Output_section*>*);
// Return whether the section is a BSS section.
static bool
is_bss_section(const Output_section*);
// Return the total size of the headers.
size_t
total_header_size(Layout* layout) const;
// Return the amount we have to subtract from the LMA to accommodate
// headers of the given size.
uint64_t
header_size_adjustment(uint64_t lma, size_t sizeof_headers) const;
// Create the segments from a PHDRS clause.
Output_segment*
create_segments_from_phdrs_clause(Layout* layout, uint64_t);
// Attach sections to segments from a PHDRS clause.
void
attach_sections_using_phdrs_clause(Layout*);
// Set addresses of segments from a PHDRS clause.
Output_segment*
set_phdrs_clause_addresses(Layout*, uint64_t);
// True if we ever saw a SECTIONS clause.
bool saw_sections_clause_;
// True if we are currently processing a SECTIONS clause.
bool in_sections_clause_;
// The list of elements in the SECTIONS clause.
Sections_elements* sections_elements_;
// The current output section, if there is one.
Output_section_definition* output_section_;
// The list of memory regions in the MEMORY clause.
Memory_regions* memory_regions_;
// The list of program headers in the PHDRS clause.
Phdrs_elements* phdrs_elements_;
// Where to put orphan sections.
Orphan_section_placement* orphan_section_placement_;
// A pointer to the last Sections_element when we see
// DATA_SEGMENT_ALIGN.
Sections_elements::iterator data_segment_align_start_;
// Whether we have seen DATA_SEGMENT_ALIGN.
bool saw_data_segment_align_;
// Whether we have seen DATA_SEGMENT_RELRO_END.
bool saw_relro_end_;
// Whether we have seen SEGMENT_START.
bool saw_segment_start_expression_;
// Whether we have created all necessary segments.
bool segments_created_;
};
// Attributes for memory regions.
enum
{
MEM_EXECUTABLE = (1 << 0),
MEM_WRITEABLE = (1 << 1),
MEM_READABLE = (1 << 2),
MEM_ALLOCATABLE = (1 << 3),
MEM_INITIALIZED = (1 << 4),
MEM_ATTR_MASK = (1 << 5) - 1
};
} // End namespace gold.
#endif // !defined(GOLD_SCRIPT_SECTIONS_H