338 lines
10 KiB
C++
338 lines
10 KiB
C++
// script-sections.h -- linker script SECTIONS for gold -*- C++ -*-
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// Copyright (C) 2008-2015 Free Software Foundation, Inc.
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// Written by Ian Lance Taylor <iant@google.com>.
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// This file is part of gold.
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3 of the License, or
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// (at your option) any later version.
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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// MA 02110-1301, USA.
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// This is for the support of the SECTIONS clause in linker scripts.
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#ifndef GOLD_SCRIPT_SECTIONS_H
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#define GOLD_SCRIPT_SECTIONS_H
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#include <cstdio>
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#include <list>
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#include <vector>
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namespace gold
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{
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struct Parser_output_section_header;
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struct Parser_output_section_trailer;
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struct Input_section_spec;
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class Expression;
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class Sections_element;
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class Memory_region;
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class Phdrs_element;
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class Output_data;
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class Output_section_definition;
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class Output_section;
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class Output_segment;
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class Orphan_section_placement;
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class Script_sections
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{
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public:
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// This is a list, not a vector, because we insert orphan sections
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// in the middle.
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typedef std::list<Sections_element*> Sections_elements;
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// Logical script section types. We map section types returned by the
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// parser into these since some section types have the same semantics.
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enum Section_type
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{
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// No section type specified.
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ST_NONE,
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// Section is NOLOAD. We allocate space in the output but section
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// is not loaded in runtime.
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ST_NOLOAD,
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// No space is allocated to section.
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ST_NOALLOC
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};
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Script_sections();
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// Start a SECTIONS clause.
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void
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start_sections();
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// Finish a SECTIONS clause.
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void
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finish_sections();
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// Return whether we ever saw a SECTIONS clause. If we did, then
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// all section layout needs to go through this class.
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bool
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saw_sections_clause() const
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{ return this->saw_sections_clause_; }
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// Return whether we are currently processing a SECTIONS clause.
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bool
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in_sections_clause() const
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{ return this->in_sections_clause_; }
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// Return whether we ever saw a PHDRS clause. We ignore the PHDRS
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// clause unless we also saw a SECTIONS clause.
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bool
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saw_phdrs_clause() const
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{ return this->saw_sections_clause_ && this->phdrs_elements_ != NULL; }
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// Start processing entries for an output section.
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void
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start_output_section(const char* name, size_t namelen,
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const Parser_output_section_header*);
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// Finish processing entries for an output section.
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void
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finish_output_section(const Parser_output_section_trailer*);
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// Add a data item to the current output section.
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void
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add_data(int size, bool is_signed, Expression* val);
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// Add a symbol to be defined.
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void
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add_symbol_assignment(const char* name, size_t length, Expression* value,
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bool provide, bool hidden);
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// Add an assignment to the special dot symbol.
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void
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add_dot_assignment(Expression* value);
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// Add an assertion.
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void
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add_assertion(Expression* check, const char* message, size_t messagelen);
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// Add a setting for the fill value.
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void
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add_fill(Expression* val);
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// Add an input section specification.
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void
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add_input_section(const Input_section_spec* spec, bool keep);
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// Saw DATA_SEGMENT_ALIGN.
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void
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data_segment_align();
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// Saw DATA_SEGMENT_RELRO_END.
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void
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data_segment_relro_end();
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// Create any required sections.
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void
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create_sections(Layout*);
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// Add any symbols we are defining to the symbol table.
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void
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add_symbols_to_table(Symbol_table*);
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// Finalize symbol values and check assertions.
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void
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finalize_symbols(Symbol_table* symtab, const Layout* layout);
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// Find the name of the output section to use for an input file name
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// and section name. This returns a name, and sets
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// *OUTPUT_SECTION_SLOT to point to the address where the actual
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// output section may be stored.
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// 1) If the input section should be discarded, this returns NULL
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// and sets *OUTPUT_SECTION_SLOT to NULL.
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// 2) If the input section is mapped by the SECTIONS clause, this
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// returns the name to use for the output section (in permanent
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// storage), and sets *OUTPUT_SECTION_SLOT to point to where the
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// output section should be stored. **OUTPUT_SECTION_SLOT will be
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// non-NULL if we have seen this output section already.
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// 3) If the input section is not mapped by the SECTIONS clause,
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// this returns SECTION_NAME, and sets *OUTPUT_SECTION_SLOT to
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// NULL.
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// PSCRIPT_SECTION_TYPE points to a location for returning the section
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// type specified in script. This can be SCRIPT_SECTION_TYPE_NONE if
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// no type is specified.
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// *KEEP indicates whether the section should survive garbage collection.
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const char*
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output_section_name(const char* file_name, const char* section_name,
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Output_section*** output_section_slot,
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Section_type* pscript_section_type,
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bool* keep);
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// Place a marker for an orphan output section into the SECTIONS
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// clause.
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void
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place_orphan(Output_section* os);
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// Set the addresses of all the output sections. Return the segment
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// which holds the file header and segment headers, if any.
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Output_segment*
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set_section_addresses(Symbol_table*, Layout*);
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// Add a program header definition.
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void
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add_phdr(const char* name, size_t namelen, unsigned int type,
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bool filehdr, bool phdrs, bool is_flags_valid, unsigned int flags,
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Expression* load_address);
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// Return the number of segments we expect to create based on the
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// SECTIONS clause.
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size_t
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expected_segment_count(const Layout*) const;
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// Add the file header and segment header to non-load segments as
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// specified by the PHDRS clause.
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void
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put_headers_in_phdrs(Output_data* file_header, Output_data* segment_headers);
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// Look for an output section by name and return the address, the
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// load address, the alignment, and the size. This is used when an
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// expression refers to an output section which was not actually
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// created. This returns true if the section was found, false
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// otherwise.
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bool
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get_output_section_info(const char* name, uint64_t* address,
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uint64_t* load_address, uint64_t* addralign,
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uint64_t* size) const;
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// Release all Output_segments. This is used in relaxation.
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void
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release_segments();
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// Whether we ever saw a SEGMENT_START expression, the presence of which
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// changes the behaviour of -Ttext, -Tdata and -Tbss options.
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bool
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saw_segment_start_expression() const
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{ return this->saw_segment_start_expression_; }
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// Set the flag which indicates whether we saw a SEGMENT_START expression.
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void
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set_saw_segment_start_expression(bool value)
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{ this->saw_segment_start_expression_ = value; }
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// Add a memory region.
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void
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add_memory_region(const char*, size_t, unsigned int,
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Expression*, Expression*);
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// Find a memory region's origin.
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Expression*
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find_memory_region_origin(const char*, size_t);
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// Find a memory region's length.
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Expression*
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find_memory_region_length(const char*, size_t);
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// Find a memory region by name.
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Memory_region*
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find_memory_region(const char*, size_t);
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// Find a memory region that should be used by a given output section.
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Memory_region*
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find_memory_region(Output_section_definition*, bool,
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Output_section_definition**);
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// Returns true if the provide block of memory is contained
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// within a memory region.
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bool
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block_in_region(Symbol_table*, Layout*, uint64_t, uint64_t) const;
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// Set the memory region of the section.
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void
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set_memory_region(Memory_region*, bool);
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// Print the contents to the FILE. This is for debugging.
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void
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print(FILE*) const;
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// Used for orphan sections.
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typedef Sections_elements::iterator Elements_iterator;
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private:
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typedef std::vector<Memory_region*> Memory_regions;
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typedef std::vector<Phdrs_element*> Phdrs_elements;
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// Create segments.
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Output_segment*
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create_segments(Layout*, uint64_t);
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// Create PT_NOTE and PT_TLS segments.
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void
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create_note_and_tls_segments(Layout*, const std::vector<Output_section*>*);
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// Return whether the section is a BSS section.
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static bool
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is_bss_section(const Output_section*);
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// Return the total size of the headers.
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size_t
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total_header_size(Layout* layout) const;
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// Return the amount we have to subtract from the LMA to accomodate
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// headers of the given size.
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uint64_t
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header_size_adjustment(uint64_t lma, size_t sizeof_headers) const;
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// Create the segments from a PHDRS clause.
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Output_segment*
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create_segments_from_phdrs_clause(Layout* layout, uint64_t);
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// Attach sections to segments from a PHDRS clause.
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void
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attach_sections_using_phdrs_clause(Layout*);
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// Set addresses of segments from a PHDRS clause.
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Output_segment*
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set_phdrs_clause_addresses(Layout*, uint64_t);
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// True if we ever saw a SECTIONS clause.
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bool saw_sections_clause_;
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// True if we are currently processing a SECTIONS clause.
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bool in_sections_clause_;
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// The list of elements in the SECTIONS clause.
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Sections_elements* sections_elements_;
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// The current output section, if there is one.
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Output_section_definition* output_section_;
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// The list of memory regions in the MEMORY clause.
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Memory_regions* memory_regions_;
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// The list of program headers in the PHDRS clause.
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Phdrs_elements* phdrs_elements_;
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// Where to put orphan sections.
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Orphan_section_placement* orphan_section_placement_;
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// A pointer to the last Sections_element when we see
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// DATA_SEGMENT_ALIGN.
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Sections_elements::iterator data_segment_align_start_;
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// Whether we have seen DATA_SEGMENT_ALIGN.
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bool saw_data_segment_align_;
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// Whether we have seen DATA_SEGMENT_RELRO_END.
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bool saw_relro_end_;
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// Whether we have seen SEGMENT_START.
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bool saw_segment_start_expression_;
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};
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// Attributes for memory regions.
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enum
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{
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MEM_EXECUTABLE = (1 << 0),
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MEM_WRITEABLE = (1 << 1),
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MEM_READABLE = (1 << 2),
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MEM_ALLOCATABLE = (1 << 3),
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MEM_INITIALIZED = (1 << 4),
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MEM_ATTR_MASK = (1 << 5) - 1
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};
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} // End namespace gold.
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#endif // !defined(GOLD_SCRIPT_SECTIONS_H
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