// layout.cc -- lay out output file sections for gold
+// 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.
+
#include "gold.h"
-#include <cassert>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <utility>
+#include "parameters.h"
+#include "options.h"
+#include "script.h"
+#include "script-sections.h"
#include "output.h"
#include "symtab.h"
+#include "dynobj.h"
+#include "ehframe.h"
+#include "compressed_output.h"
+#include "reloc.h"
#include "layout.h"
namespace gold
// have been read.
void
-Layout_task_runner::run(Workqueue* workqueue)
+Layout_task_runner::run(Workqueue* workqueue, const Task* task)
{
off_t file_size = this->layout_->finalize(this->input_objects_,
- this->symtab_);
+ this->symtab_,
+ this->target_,
+ task);
// Now we know the final size of the output file and we know where
// each piece of information goes.
- Output_file* of = new Output_file(this->options_);
+ Output_file* of = new Output_file(parameters->options().output_file_name());
+ if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
+ of->set_is_temporary();
of->open(file_size);
// Queue up the final set of tasks.
// Layout methods.
-Layout::Layout(const General_options& options)
- : options_(options), namepool_(), sympool_(), signatures_(),
+Layout::Layout(const General_options& options, Script_options* script_options)
+ : options_(options), script_options_(script_options), namepool_(),
+ sympool_(), dynpool_(), signatures_(),
section_name_map_(), segment_list_(), section_list_(),
- special_output_list_(), tls_segment_(NULL)
+ unattached_section_list_(), special_output_list_(),
+ section_headers_(NULL), tls_segment_(NULL), symtab_section_(NULL),
+ dynsym_section_(NULL), dynamic_section_(NULL), dynamic_data_(NULL),
+ eh_frame_section_(NULL), group_signatures_(), output_file_size_(-1),
+ input_requires_executable_stack_(false),
+ input_with_gnu_stack_note_(false),
+ input_without_gnu_stack_note_(false),
+ has_static_tls_(false),
+ any_postprocessing_sections_(false)
{
// Make space for more than enough segments for a typical file.
// This is just for efficiency--it's OK if we wind up needing more.
- segment_list_.reserve(12);
+ this->segment_list_.reserve(12);
+
+ // We expect two unattached Output_data objects: the file header and
+ // the segment headers.
+ this->special_output_list_.reserve(2);
}
// Hash a key we use to look up an output section mapping.
return k.first + k.second.first + k.second.second;
}
+// Return whether PREFIX is a prefix of STR.
+
+static inline bool
+is_prefix_of(const char* prefix, const char* str)
+{
+ return strncmp(prefix, str, strlen(prefix)) == 0;
+}
+
+// Returns whether the given section is in the list of
+// debug-sections-used-by-some-version-of-gdb. Currently,
+// we've checked versions of gdb up to and including 6.7.1.
+
+static const char* gdb_sections[] =
+{ ".debug_abbrev",
+ // ".debug_aranges", // not used by gdb as of 6.7.1
+ ".debug_frame",
+ ".debug_info",
+ ".debug_line",
+ ".debug_loc",
+ ".debug_macinfo",
+ // ".debug_pubnames", // not used by gdb as of 6.7.1
+ ".debug_ranges",
+ ".debug_str",
+};
+
+static inline bool
+is_gdb_debug_section(const char* str)
+{
+ // We can do this faster: binary search or a hashtable. But why bother?
+ for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i)
+ if (strcmp(str, gdb_sections[i]) == 0)
+ return true;
+ return false;
+}
+
// Whether to include this section in the link.
template<int size, bool big_endian>
bool
-Layout::include_section(Object*, const char*,
+Layout::include_section(Sized_relobj<size, big_endian>*, const char* name,
const elfcpp::Shdr<size, big_endian>& shdr)
{
- // Some section types are never linked. Some are only linked when
- // doing a relocateable link.
switch (shdr.get_sh_type())
{
case elfcpp::SHT_NULL:
case elfcpp::SHT_RELA:
case elfcpp::SHT_REL:
case elfcpp::SHT_GROUP:
- return this->options_.is_relocatable();
+ // If we are emitting relocations these should be handled
+ // elsewhere.
+ gold_assert(!parameters->options().relocatable()
+ && !parameters->options().emit_relocs());
+ return false;
+
+ case elfcpp::SHT_PROGBITS:
+ if (parameters->options().strip_debug()
+ && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
+ {
+ // Debugging sections can only be recognized by name.
+ if (is_prefix_of(".debug", name)
+ || is_prefix_of(".gnu.linkonce.wi.", name)
+ || is_prefix_of(".line", name)
+ || is_prefix_of(".stab", name))
+ return false;
+ }
+ if (parameters->options().strip_debug_gdb()
+ && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
+ {
+ // Debugging sections can only be recognized by name.
+ if (is_prefix_of(".debug", name)
+ && !is_gdb_debug_section(name))
+ return false;
+ }
+ return true;
default:
- // FIXME: Handle stripping debug sections here.
return true;
}
}
Output_section*
Layout::find_output_section(const char* name) const
{
- for (Section_name_map::const_iterator p = this->section_name_map_.begin();
- p != this->section_name_map_.end();
+ for (Section_list::const_iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
++p)
- if (strcmp(p->second->name(), name) == 0)
- return p->second;
+ if (strcmp((*p)->name(), name) == 0)
+ return *p;
return NULL;
}
}
// Return the output section to use for section NAME with type TYPE
-// and section flags FLAGS.
+// and section flags FLAGS. NAME must be canonicalized in the string
+// pool, and NAME_KEY is the key.
Output_section*
Layout::get_output_section(const char* name, Stringpool::Key name_key,
elfcpp::Elf_Word type, elfcpp::Elf_Xword flags)
{
- // We should ignore some flags.
- flags &= ~ (elfcpp::SHF_INFO_LINK
- | elfcpp::SHF_LINK_ORDER
- | elfcpp::SHF_GROUP);
-
const Key key(name_key, std::make_pair(type, flags));
const std::pair<Key, Output_section*> v(key, NULL);
std::pair<Section_name_map::iterator, bool> ins(
else
{
// This is the first time we've seen this name/type/flags
- // combination.
- Output_section* os = this->make_output_section(name, type, flags);
+ // combination. If the section has contents but no flags, then
+ // see whether we have an existing section with the same name.
+ // This is a workaround for cases where assembler code forgets
+ // to set section flags, and the GNU linker would simply pick an
+ // existing section with the same name. FIXME: Perhaps there
+ // should be an option to control this.
+ Output_section* os = NULL;
+ if (type == elfcpp::SHT_PROGBITS && flags == 0)
+ {
+ os = this->find_output_section(name);
+ if (os != NULL && os->type() != elfcpp::SHT_PROGBITS)
+ os = NULL;
+ }
+ if (os == NULL)
+ os = this->make_output_section(name, type, flags);
ins.first->second = os;
return os;
}
}
+// Pick the output section to use for section NAME, in input file
+// RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a
+// linker created section. ADJUST_NAME is true if we should apply the
+// standard name mappings in Layout::output_section_name. This will
+// return NULL if the input section should be discarded.
+
+Output_section*
+Layout::choose_output_section(const Relobj* relobj, const char* name,
+ elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
+ bool adjust_name)
+{
+ // We should ignore some flags. FIXME: This will need some
+ // adjustment for ld -r.
+ flags &= ~ (elfcpp::SHF_INFO_LINK
+ | elfcpp::SHF_LINK_ORDER
+ | elfcpp::SHF_GROUP
+ | elfcpp::SHF_MERGE
+ | elfcpp::SHF_STRINGS);
+
+ if (this->script_options_->saw_sections_clause())
+ {
+ // We are using a SECTIONS clause, so the output section is
+ // chosen based only on the name.
+
+ Script_sections* ss = this->script_options_->script_sections();
+ const char* file_name = relobj == NULL ? NULL : relobj->name().c_str();
+ Output_section** output_section_slot;
+ name = ss->output_section_name(file_name, name, &output_section_slot);
+ if (name == NULL)
+ {
+ // The SECTIONS clause says to discard this input section.
+ return NULL;
+ }
+
+ // If this is an orphan section--one not mentioned in the linker
+ // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the
+ // default processing below.
+
+ if (output_section_slot != NULL)
+ {
+ if (*output_section_slot != NULL)
+ return *output_section_slot;
+
+ // We don't put sections found in the linker script into
+ // SECTION_NAME_MAP_. That keeps us from getting confused
+ // if an orphan section is mapped to a section with the same
+ // name as one in the linker script.
+
+ name = this->namepool_.add(name, false, NULL);
+
+ Output_section* os = this->make_output_section(name, type, flags);
+ os->set_found_in_sections_clause();
+ *output_section_slot = os;
+ return os;
+ }
+ }
+
+ // FIXME: Handle SHF_OS_NONCONFORMING somewhere.
+
+ // Turn NAME from the name of the input section into the name of the
+ // output section.
+
+ size_t len = strlen(name);
+ if (adjust_name && !parameters->options().relocatable())
+ name = Layout::output_section_name(name, &len);
+
+ Stringpool::Key name_key;
+ name = this->namepool_.add_with_length(name, len, true, &name_key);
+
+ // Find or make the output section. The output section is selected
+ // based on the section name, type, and flags.
+ return this->get_output_section(name, name_key, type, flags);
+}
+
// Return the output section to use for input section SHNDX, with name
-// NAME, with header HEADER, from object OBJECT. Set *OFF to the
-// offset of this input section without the output section.
+// NAME, with header HEADER, from object OBJECT. 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 *OFF to the offset of this
+// input section without the output section. Return NULL if the
+// section should be discarded. Set *OFF to -1 if the section
+// contents should not be written directly to the output file, but
+// will instead receive special handling.
template<int size, bool big_endian>
Output_section*
-Layout::layout(Relobj* object, unsigned int shndx, const char* name,
- const elfcpp::Shdr<size, big_endian>& shdr, off_t* off)
+Layout::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, off_t* off)
{
if (!this->include_section(object, name, shdr))
return NULL;
- // If we are not doing a relocateable link, choose the name to use
- // for the output section.
- size_t len = strlen(name);
- if (!this->options_.is_relocatable())
- name = Layout::output_section_name(name, &len);
+ Output_section* os;
+
+ // In a relocatable link a grouped section must not be combined with
+ // any other sections.
+ if (parameters->options().relocatable()
+ && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0)
+ {
+ name = this->namepool_.add(name, true, NULL);
+ os = this->make_output_section(name, shdr.get_sh_type(),
+ shdr.get_sh_flags());
+ }
+ else
+ {
+ os = this->choose_output_section(object, name, shdr.get_sh_type(),
+ shdr.get_sh_flags(), true);
+ if (os == NULL)
+ return NULL;
+ }
+
+ // FIXME: Handle SHF_LINK_ORDER somewhere.
- // FIXME: Handle SHF_OS_NONCONFORMING here.
+ *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
+ this->script_options_->saw_sections_clause());
- // Canonicalize the section name.
- Stringpool::Key name_key;
- name = this->namepool_.add(name, len, &name_key);
+ return os;
+}
- // Find the output section. The output section is selected based on
- // the section name, type, and flags.
- Output_section* os = this->get_output_section(name, name_key,
- shdr.get_sh_type(),
- shdr.get_sh_flags());
+// Handle a relocation section when doing a relocatable link.
- // FIXME: Handle SHF_LINK_ORDER somewhere.
+template<int size, bool big_endian>
+Output_section*
+Layout::layout_reloc(Sized_relobj<size, big_endian>* object,
+ unsigned int,
+ const elfcpp::Shdr<size, big_endian>& shdr,
+ Output_section* data_section,
+ Relocatable_relocs* rr)
+{
+ gold_assert(parameters->options().relocatable()
+ || parameters->options().emit_relocs());
+
+ int sh_type = shdr.get_sh_type();
+
+ std::string name;
+ if (sh_type == elfcpp::SHT_REL)
+ name = ".rel";
+ else if (sh_type == elfcpp::SHT_RELA)
+ name = ".rela";
+ else
+ gold_unreachable();
+ name += data_section->name();
+
+ Output_section* os = this->choose_output_section(object, name.c_str(),
+ sh_type,
+ shdr.get_sh_flags(),
+ false);
+
+ os->set_should_link_to_symtab();
+ os->set_info_section(data_section);
+
+ Output_section_data* posd;
+ if (sh_type == elfcpp::SHT_REL)
+ {
+ os->set_entsize(elfcpp::Elf_sizes<size>::rel_size);
+ posd = new Output_relocatable_relocs<elfcpp::SHT_REL,
+ size,
+ big_endian>(rr);
+ }
+ else if (sh_type == elfcpp::SHT_RELA)
+ {
+ os->set_entsize(elfcpp::Elf_sizes<size>::rela_size);
+ posd = new Output_relocatable_relocs<elfcpp::SHT_RELA,
+ size,
+ big_endian>(rr);
+ }
+ else
+ gold_unreachable();
+
+ os->add_output_section_data(posd);
+ rr->set_output_data(posd);
+
+ return os;
+}
+
+// Handle a group section when doing a relocatable link.
+
+template<int size, bool big_endian>
+void
+Layout::layout_group(Symbol_table* symtab,
+ Sized_relobj<size, big_endian>* object,
+ unsigned int,
+ const char* group_section_name,
+ const char* signature,
+ const elfcpp::Shdr<size, big_endian>& shdr,
+ const elfcpp::Elf_Word* contents)
+{
+ gold_assert(parameters->options().relocatable());
+ gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
+ group_section_name = this->namepool_.add(group_section_name, true, NULL);
+ Output_section* os = this->make_output_section(group_section_name,
+ elfcpp::SHT_GROUP,
+ shdr.get_sh_flags());
+
+ // We need to find a symbol with the signature in the symbol table.
+ // If we don't find one now, we need to look again later.
+ Symbol* sym = symtab->lookup(signature, NULL);
+ if (sym != NULL)
+ os->set_info_symndx(sym);
+ else
+ {
+ // We will wind up using a symbol whose name is the signature.
+ // So just put the signature in the symbol name pool to save it.
+ signature = symtab->canonicalize_name(signature);
+ this->group_signatures_.push_back(Group_signature(os, signature));
+ }
+
+ os->set_should_link_to_symtab();
+ os->set_entsize(4);
+
+ section_size_type entry_count =
+ convert_to_section_size_type(shdr.get_sh_size() / 4);
+ Output_section_data* posd =
+ new Output_data_group<size, big_endian>(object, entry_count, contents);
+ os->add_output_section_data(posd);
+}
+
+// Special GNU handling of sections name .eh_frame. They will
+// normally hold exception frame data as defined by the C++ ABI
+// (http://codesourcery.com/cxx-abi/).
+
+template<int size, bool big_endian>
+Output_section*
+Layout::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* off)
+{
+ gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS);
+ gold_assert(shdr.get_sh_flags() == elfcpp::SHF_ALLOC);
+
+ const char* const name = ".eh_frame";
+ Output_section* os = this->choose_output_section(object,
+ name,
+ elfcpp::SHT_PROGBITS,
+ elfcpp::SHF_ALLOC,
+ false);
+ if (os == NULL)
+ return NULL;
+
+ if (this->eh_frame_section_ == NULL)
+ {
+ this->eh_frame_section_ = os;
+ this->eh_frame_data_ = new Eh_frame();
+ os->add_output_section_data(this->eh_frame_data_);
- *off = os->add_input_section(object, shndx, name, shdr);
+ if (this->options_.eh_frame_hdr())
+ {
+ Output_section* hdr_os =
+ this->choose_output_section(NULL,
+ ".eh_frame_hdr",
+ elfcpp::SHT_PROGBITS,
+ elfcpp::SHF_ALLOC,
+ false);
+
+ if (hdr_os != NULL)
+ {
+ Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os,
+ this->eh_frame_data_);
+ hdr_os->add_output_section_data(hdr_posd);
+
+ hdr_os->set_after_input_sections();
+
+ if (!this->script_options_->saw_phdrs_clause())
+ {
+ Output_segment* hdr_oseg;
+ hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME,
+ elfcpp::PF_R);
+ hdr_oseg->add_output_section(hdr_os, elfcpp::PF_R);
+ }
+
+ this->eh_frame_data_->set_eh_frame_hdr(hdr_posd);
+ }
+ }
+ }
+
+ gold_assert(this->eh_frame_section_ == os);
+
+ if (this->eh_frame_data_->add_ehframe_input_section(object,
+ symbols,
+ symbols_size,
+ symbol_names,
+ symbol_names_size,
+ shndx,
+ reloc_shndx,
+ reloc_type))
+ *off = -1;
+ else
+ {
+ // We couldn't handle this .eh_frame section for some reason.
+ // Add it as a normal section.
+ bool saw_sections_clause = this->script_options_->saw_sections_clause();
+ *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
+ saw_sections_clause);
+ }
return os;
}
elfcpp::Elf_Xword flags,
Output_section_data* posd)
{
- // Canonicalize the name.
- Stringpool::Key name_key;
- name = this->namepool_.add(name, &name_key);
-
- Output_section* os = this->get_output_section(name, name_key, type, flags);
- os->add_output_section_data(posd);
+ Output_section* os = this->choose_output_section(NULL, name, type, flags,
+ false);
+ if (os != NULL)
+ os->add_output_section_data(posd);
}
// Map section flags to segment flags.
return ret;
}
+// Sometimes we compress sections. This is typically done for
+// sections that are not part of normal program execution (such as
+// .debug_* sections), and where the readers of these sections know
+// how to deal with compressed sections. (To make it easier for them,
+// we will rename the ouput section in such cases from .foo to
+// .foo.zlib.nnnn, where nnnn is the uncompressed size.) This routine
+// doesn't say for certain whether we'll compress -- it depends on
+// commandline options as well -- just whether this section is a
+// candidate for compression.
+
+static bool
+is_compressible_debug_section(const char* secname)
+{
+ return (strncmp(secname, ".debug", sizeof(".debug") - 1) == 0);
+}
+
// Make a new Output_section, and attach it to segments as
// appropriate.
Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
elfcpp::Elf_Xword flags)
{
- Output_section* os = new Output_section(name, type, flags, true);
+ Output_section* os;
+ if ((flags & elfcpp::SHF_ALLOC) == 0
+ && this->options_.compress_debug_sections()
+ && is_compressible_debug_section(name))
+ os = new Output_compressed_section(&this->options_, name, type, flags);
+ else
+ os = new Output_section(name, type, flags);
+
+ this->section_list_.push_back(os);
if ((flags & elfcpp::SHF_ALLOC) == 0)
- this->section_list_.push_back(os);
+ this->unattached_section_list_.push_back(os);
else
{
+ if (parameters->options().relocatable())
+ return os;
+
+ // If we have a SECTIONS clause, we can't handle the attachment
+ // to segments until after we've seen all the sections.
+ if (this->script_options_->saw_sections_clause())
+ return os;
+
+ gold_assert(!this->script_options_->saw_phdrs_clause());
+
// This output section goes into a PT_LOAD segment.
elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
- // The only thing we really care about for PT_LOAD segments is
- // whether or not they are writable, so that is how we search
- // for them. People who need segments sorted on some other
- // basis will have to wait until we implement a mechanism for
- // them to describe the segments they want.
+ // In general the only thing we really care about for PT_LOAD
+ // segments is whether or not they are writable, so that is how
+ // we search for them. People who need segments sorted on some
+ // other basis will have to use a linker script.
Segment_list::const_iterator p;
for (p = this->segment_list_.begin();
if ((*p)->type() == elfcpp::PT_LOAD
&& ((*p)->flags() & elfcpp::PF_W) == (seg_flags & elfcpp::PF_W))
{
+ // If -Tbss was specified, we need to separate the data
+ // and BSS segments.
+ if (this->options_.user_set_Tbss())
+ {
+ if ((type == elfcpp::SHT_NOBITS)
+ == (*p)->has_any_data_sections())
+ continue;
+ }
+
(*p)->add_output_section(os, seg_flags);
break;
}
if (p == this->segment_list_.end())
{
- Output_segment* oseg = new Output_segment(elfcpp::PT_LOAD,
- seg_flags);
- this->segment_list_.push_back(oseg);
+ Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD,
+ seg_flags);
oseg->add_output_section(os, seg_flags);
}
if (p == this->segment_list_.end())
{
- Output_segment* oseg = new Output_segment(elfcpp::PT_NOTE,
- seg_flags);
- this->segment_list_.push_back(oseg);
+ Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE,
+ seg_flags);
oseg->add_output_section(os, seg_flags);
}
}
if ((flags & elfcpp::SHF_TLS) != 0)
{
if (this->tls_segment_ == NULL)
- {
- this->tls_segment_ = new Output_segment(elfcpp::PT_TLS,
- seg_flags);
- this->segment_list_.push_back(this->tls_segment_);
- }
+ this->tls_segment_ = this->make_output_segment(elfcpp::PT_TLS,
+ seg_flags);
this->tls_segment_->add_output_section(os, seg_flags);
}
}
return os;
}
+// Make an output section for a script.
+
+Output_section*
+Layout::make_output_section_for_script(const char* name)
+{
+ name = this->namepool_.add(name, false, NULL);
+ Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
+ elfcpp::SHF_ALLOC);
+ os->set_found_in_sections_clause();
+ return os;
+}
+
+// Return the number of segments we expect to see.
+
+size_t
+Layout::expected_segment_count() const
+{
+ size_t ret = this->segment_list_.size();
+
+ // If we didn't see a SECTIONS clause in a linker script, we should
+ // already have the complete list of segments. Otherwise we ask the
+ // SECTIONS clause how many segments it expects, and add in the ones
+ // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.)
+
+ if (!this->script_options_->saw_sections_clause())
+ return ret;
+ else
+ {
+ const Script_sections* ss = this->script_options_->script_sections();
+ return ret + ss->expected_segment_count(this);
+ }
+}
+
+// Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK
+// is whether we saw a .note.GNU-stack section in the object file.
+// GNU_STACK_FLAGS is the section flags. The flags give the
+// protection required for stack memory. We record this in an
+// executable as a PT_GNU_STACK segment. If an object file does not
+// have a .note.GNU-stack segment, we must assume that it is an old
+// object. On some targets that will force an executable stack.
+
+void
+Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags)
+{
+ if (!seen_gnu_stack)
+ this->input_without_gnu_stack_note_ = true;
+ else
+ {
+ this->input_with_gnu_stack_note_ = true;
+ if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
+ this->input_requires_executable_stack_ = true;
+ }
+}
+
+// Create the dynamic sections which are needed before we read the
+// relocs.
+
+void
+Layout::create_initial_dynamic_sections(Symbol_table* symtab)
+{
+ if (parameters->doing_static_link())
+ return;
+
+ this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic",
+ elfcpp::SHT_DYNAMIC,
+ (elfcpp::SHF_ALLOC
+ | elfcpp::SHF_WRITE),
+ false);
+
+ symtab->define_in_output_data("_DYNAMIC", NULL, this->dynamic_section_, 0, 0,
+ elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
+ elfcpp::STV_HIDDEN, 0, false, false);
+
+ this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_);
+
+ this->dynamic_section_->add_output_section_data(this->dynamic_data_);
+}
+
+// For each output section whose name can be represented as C symbol,
+// define __start and __stop symbols for the section. This is a GNU
+// extension.
+
+void
+Layout::define_section_symbols(Symbol_table* symtab)
+{
+ for (Section_list::const_iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
+ ++p)
+ {
+ const char* const name = (*p)->name();
+ if (name[strspn(name,
+ ("0123456789"
+ "ABCDEFGHIJKLMNOPWRSTUVWXYZ"
+ "abcdefghijklmnopqrstuvwxyz"
+ "_"))]
+ == '\0')
+ {
+ const std::string name_string(name);
+ const std::string start_name("__start_" + name_string);
+ const std::string stop_name("__stop_" + name_string);
+
+ symtab->define_in_output_data(start_name.c_str(),
+ NULL, // version
+ *p,
+ 0, // value
+ 0, // symsize
+ elfcpp::STT_NOTYPE,
+ elfcpp::STB_GLOBAL,
+ elfcpp::STV_DEFAULT,
+ 0, // nonvis
+ false, // offset_is_from_end
+ true); // only_if_ref
+
+ symtab->define_in_output_data(stop_name.c_str(),
+ NULL, // version
+ *p,
+ 0, // value
+ 0, // symsize
+ elfcpp::STT_NOTYPE,
+ elfcpp::STB_GLOBAL,
+ elfcpp::STV_DEFAULT,
+ 0, // nonvis
+ true, // offset_is_from_end
+ true); // only_if_ref
+ }
+ }
+}
+
+// Define symbols for group signatures.
+
+void
+Layout::define_group_signatures(Symbol_table* symtab)
+{
+ for (Group_signatures::iterator p = this->group_signatures_.begin();
+ p != this->group_signatures_.end();
+ ++p)
+ {
+ Symbol* sym = symtab->lookup(p->signature, NULL);
+ if (sym != NULL)
+ p->section->set_info_symndx(sym);
+ else
+ {
+ // Force the name of the group section to the group
+ // signature, and use the group's section symbol as the
+ // signature symbol.
+ if (strcmp(p->section->name(), p->signature) != 0)
+ {
+ const char* name = this->namepool_.add(p->signature,
+ true, NULL);
+ p->section->set_name(name);
+ }
+ p->section->set_needs_symtab_index();
+ p->section->set_info_section_symndx(p->section);
+ }
+ }
+
+ this->group_signatures_.clear();
+}
+
// Find the first read-only PT_LOAD segment, creating one if
// necessary.
return *p;
}
- Output_segment* load_seg = new Output_segment(elfcpp::PT_LOAD, elfcpp::PF_R);
- this->segment_list_.push_back(load_seg);
+ gold_assert(!this->script_options_->saw_phdrs_clause());
+
+ Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD,
+ elfcpp::PF_R);
return load_seg;
}
// This function returns the size of the output file.
off_t
-Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab)
+Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab,
+ Target* target, const Task* task)
{
- const int size = input_objects->target()->get_size();
+ target->finalize_sections(this);
+
+ this->count_local_symbols(task, input_objects);
+
+ this->create_gold_note();
+ this->create_executable_stack_info(target);
Output_segment* phdr_seg = NULL;
- if (input_objects->any_dynamic())
+ if (!parameters->options().relocatable() && !parameters->doing_static_link())
{
// There was a dynamic object in the link. We need to create
// some information for the dynamic linker.
// Create the PT_PHDR segment which will hold the program
// headers.
- phdr_seg = new Output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
- this->segment_list_.push_back(phdr_seg);
+ if (!this->script_options_->saw_phdrs_clause())
+ phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R);
+
+ // Create the dynamic symbol table, including the hash table.
+ Output_section* dynstr;
+ std::vector<Symbol*> dynamic_symbols;
+ unsigned int local_dynamic_count;
+ Versions versions(*this->script_options()->version_script_info(),
+ &this->dynpool_);
+ this->create_dynamic_symtab(input_objects, symtab, &dynstr,
+ &local_dynamic_count, &dynamic_symbols,
+ &versions);
- // Create the dynamic symbol table, including the hash table,
- // the dynamic relocations, and the version sections.
- this->create_dynamic_symtab(size, symtab);
+ // Create the .interp section to hold the name of the
+ // interpreter, and put it in a PT_INTERP segment.
+ if (!parameters->options().shared())
+ this->create_interp(target);
- // Create the .dynamic section to hold the dynamic data, and put
+ // Finish the .dynamic section to hold the dynamic data, and put
// it in a PT_DYNAMIC segment.
- this->create_dynamic_section();
+ this->finish_dynamic_section(input_objects, symtab);
- // Create the .interp section to hold the name of the
- // interpreter, and put it in a PT_INTERP segment.
- this->create_interp(input_objects->target());
+ // We should have added everything we need to the dynamic string
+ // table.
+ this->dynpool_.set_string_offsets();
+
+ // Create the version sections. We can't do this until the
+ // dynamic string table is complete.
+ this->create_version_sections(&versions, symtab, local_dynamic_count,
+ dynamic_symbols, dynstr);
}
- // FIXME: Handle PT_GNU_STACK.
+ // If there is a SECTIONS clause, put all the input sections into
+ // the required order.
+ Output_segment* load_seg;
+ if (this->script_options_->saw_sections_clause())
+ load_seg = this->set_section_addresses_from_script(symtab);
+ else if (parameters->options().relocatable())
+ load_seg = NULL;
+ else
+ load_seg = this->find_first_load_seg();
+
+ if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF)
+ load_seg = NULL;
- Output_segment* load_seg = this->find_first_load_seg();
+ gold_assert(phdr_seg == NULL || load_seg != NULL);
// Lay out the segment headers.
- bool big_endian = input_objects->target()->is_big_endian();
Output_segment_headers* segment_headers;
- segment_headers = new Output_segment_headers(size, big_endian,
- this->segment_list_);
- load_seg->add_initial_output_data(segment_headers);
- this->special_output_list_.push_back(segment_headers);
- if (phdr_seg != NULL)
- phdr_seg->add_initial_output_data(segment_headers);
+ if (parameters->options().relocatable())
+ segment_headers = NULL;
+ else
+ {
+ segment_headers = new Output_segment_headers(this->segment_list_);
+ if (load_seg != NULL)
+ load_seg->add_initial_output_data(segment_headers);
+ if (phdr_seg != NULL)
+ phdr_seg->add_initial_output_data(segment_headers);
+ }
// Lay out the file header.
Output_file_header* file_header;
- file_header = new Output_file_header(size,
- big_endian,
- this->options_,
- input_objects->target(),
- symtab,
- segment_headers);
- load_seg->add_initial_output_data(file_header);
+ file_header = new Output_file_header(target, symtab, segment_headers,
+ this->options_.entry());
+ if (load_seg != NULL)
+ load_seg->add_initial_output_data(file_header);
+
this->special_output_list_.push_back(file_header);
+ if (segment_headers != NULL)
+ this->special_output_list_.push_back(segment_headers);
+
+ if (this->script_options_->saw_phdrs_clause()
+ && !parameters->options().relocatable())
+ {
+ // Support use of FILEHDRS and PHDRS attachments in a PHDRS
+ // clause in a linker script.
+ Script_sections* ss = this->script_options_->script_sections();
+ ss->put_headers_in_phdrs(file_header, segment_headers);
+ }
// We set the output section indexes in set_segment_offsets and
- // set_section_offsets.
+ // set_section_indexes.
unsigned int shndx = 1;
// Set the file offsets of all the segments, and all the sections
// they contain.
- off_t off = this->set_segment_offsets(input_objects->target(), load_seg,
- &shndx);
+ off_t off;
+ if (!parameters->options().relocatable())
+ off = this->set_segment_offsets(target, load_seg, &shndx);
+ else
+ off = this->set_relocatable_section_offsets(file_header, &shndx);
+
+ // Set the file offsets of all the non-data sections we've seen so
+ // far which don't have to wait for the input sections. We need
+ // this in order to finalize local symbols in non-allocated
+ // sections.
+ off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
// Create the symbol table sections.
- // FIXME: We don't need to do this if we are stripping symbols.
- Output_section* osymtab;
- Output_section* ostrtab;
- this->create_symtab_sections(size, input_objects, symtab, &off,
- &osymtab, &ostrtab);
+ this->create_symtab_sections(input_objects, symtab, &off);
+ if (!parameters->doing_static_link())
+ this->assign_local_dynsym_offsets(input_objects);
+
+ // Process any symbol assignments from a linker script. This must
+ // be called after the symbol table has been finalized.
+ this->script_options_->finalize_symbols(symtab, this);
// Create the .shstrtab section.
Output_section* shstrtab_section = this->create_shstrtab();
- // Set the file offsets of all the sections not associated with
- // segments.
- off = this->set_section_offsets(off, &shndx);
+ // Set the file offsets of the rest of the non-data sections which
+ // don't have to wait for the input sections.
+ off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
- // Now the section index of OSTRTAB is set.
- osymtab->set_link(ostrtab->out_shndx());
+ // Now that all sections have been created, set the section indexes.
+ shndx = this->set_section_indexes(shndx);
// Create the section table header.
- Output_section_headers* oshdrs = this->create_shdrs(size, big_endian, &off);
+ this->create_shdrs(&off);
- file_header->set_section_info(oshdrs, shstrtab_section);
+ // If there are no sections which require postprocessing, we can
+ // handle the section names now, and avoid a resize later.
+ if (!this->any_postprocessing_sections_)
+ off = this->set_section_offsets(off,
+ STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
- // Now we know exactly where everything goes in the output file.
+ file_header->set_section_info(this->section_headers_, shstrtab_section);
+
+ // Now we know exactly where everything goes in the output file
+ // (except for non-allocated sections which require postprocessing).
+ Output_data::layout_complete();
+
+ this->output_file_size_ = off;
return off;
}
-// Return whether SEG1 should be before SEG2 in the output file. This
-// is based entirely on the segment type and flags. When this is
-// called the segment addresses has normally not yet been set.
+// Create a .note section for an executable or shared library. This
+// records the version of gold used to create the binary.
-bool
-Layout::segment_precedes(const Output_segment* seg1,
- const Output_segment* seg2)
+void
+Layout::create_gold_note()
{
- elfcpp::Elf_Word type1 = seg1->type();
- elfcpp::Elf_Word type2 = seg2->type();
+ if (parameters->options().relocatable())
+ return;
+
+ // Authorities all agree that the values in a .note field should
+ // be aligned on 4-byte boundaries for 32-bit binaries. However,
+ // they differ on what the alignment is for 64-bit binaries.
+ // The GABI says unambiguously they take 8-byte alignment:
+ // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section
+ // Other documentation says alignment should always be 4 bytes:
+ // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format
+ // GNU ld and GNU readelf both support the latter (at least as of
+ // version 2.16.91), and glibc always generates the latter for
+ // .note.ABI-tag (as of version 1.6), so that's the one we go with
+ // here.
+#ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default.
+ const int size = parameters->target().get_size();
+#else
+ const int size = 32;
+#endif
+
+ // The contents of the .note section.
+ const char* name = "GNU";
+ std::string desc(std::string("gold ") + gold::get_version_string());
+ size_t namesz = strlen(name) + 1;
+ size_t aligned_namesz = align_address(namesz, size / 8);
+ size_t descsz = desc.length() + 1;
+ size_t aligned_descsz = align_address(descsz, size / 8);
+ const int note_type = 4;
+
+ size_t notesz = 3 * (size / 8) + aligned_namesz + aligned_descsz;
+
+ unsigned char buffer[128];
+ gold_assert(sizeof buffer >= notesz);
+ memset(buffer, 0, notesz);
+
+ bool is_big_endian = parameters->target().is_big_endian();
- // The single PT_PHDR segment is required to precede any loadable
- // segment. We simply make it always first.
- if (type1 == elfcpp::PT_PHDR)
+ if (size == 32)
{
- assert(type2 != elfcpp::PT_PHDR);
- return true;
+ if (!is_big_endian)
+ {
+ elfcpp::Swap<32, false>::writeval(buffer, namesz);
+ elfcpp::Swap<32, false>::writeval(buffer + 4, descsz);
+ elfcpp::Swap<32, false>::writeval(buffer + 8, note_type);
+ }
+ else
+ {
+ elfcpp::Swap<32, true>::writeval(buffer, namesz);
+ elfcpp::Swap<32, true>::writeval(buffer + 4, descsz);
+ elfcpp::Swap<32, true>::writeval(buffer + 8, note_type);
+ }
}
- if (type2 == elfcpp::PT_PHDR)
- return false;
-
- // The single PT_INTERP segment is required to precede any loadable
- // segment. We simply make it always second.
- if (type1 == elfcpp::PT_INTERP)
+ else if (size == 64)
{
- assert(type2 != elfcpp::PT_INTERP);
- return true;
+ if (!is_big_endian)
+ {
+ elfcpp::Swap<64, false>::writeval(buffer, namesz);
+ elfcpp::Swap<64, false>::writeval(buffer + 8, descsz);
+ elfcpp::Swap<64, false>::writeval(buffer + 16, note_type);
+ }
+ else
+ {
+ elfcpp::Swap<64, true>::writeval(buffer, namesz);
+ elfcpp::Swap<64, true>::writeval(buffer + 8, descsz);
+ elfcpp::Swap<64, true>::writeval(buffer + 16, note_type);
+ }
}
- if (type2 == elfcpp::PT_INTERP)
- return false;
+ else
+ gold_unreachable();
- // We then put PT_LOAD segments before any other segments.
+ memcpy(buffer + 3 * (size / 8), name, namesz);
+ memcpy(buffer + 3 * (size / 8) + aligned_namesz, desc.data(), descsz);
+
+ const char* note_name = this->namepool_.add(".note", false, NULL);
+ Output_section* os = this->make_output_section(note_name,
+ elfcpp::SHT_NOTE,
+ 0);
+ Output_section_data* posd = new Output_data_const(buffer, notesz,
+ size / 8);
+ os->add_output_section_data(posd);
+}
+
+// Record whether the stack should be executable. This can be set
+// from the command line using the -z execstack or -z noexecstack
+// options. Otherwise, if any input file has a .note.GNU-stack
+// section with the SHF_EXECINSTR flag set, the stack should be
+// executable. Otherwise, if at least one input file a
+// .note.GNU-stack section, and some input file has no .note.GNU-stack
+// section, we use the target default for whether the stack should be
+// executable. Otherwise, we don't generate a stack note. When
+// generating a object file, we create a .note.GNU-stack section with
+// the appropriate marking. When generating an executable or shared
+// library, we create a PT_GNU_STACK segment.
+
+void
+Layout::create_executable_stack_info(const Target* target)
+{
+ bool is_stack_executable;
+ if (this->options_.is_execstack_set())
+ is_stack_executable = this->options_.is_stack_executable();
+ else if (!this->input_with_gnu_stack_note_)
+ return;
+ else
+ {
+ if (this->input_requires_executable_stack_)
+ is_stack_executable = true;
+ else if (this->input_without_gnu_stack_note_)
+ is_stack_executable = target->is_default_stack_executable();
+ else
+ is_stack_executable = false;
+ }
+
+ if (parameters->options().relocatable())
+ {
+ const char* name = this->namepool_.add(".note.GNU-stack", false, NULL);
+ elfcpp::Elf_Xword flags = 0;
+ if (is_stack_executable)
+ flags |= elfcpp::SHF_EXECINSTR;
+ this->make_output_section(name, elfcpp::SHT_PROGBITS, flags);
+ }
+ else
+ {
+ if (this->script_options_->saw_phdrs_clause())
+ return;
+ int flags = elfcpp::PF_R | elfcpp::PF_W;
+ if (is_stack_executable)
+ flags |= elfcpp::PF_X;
+ this->make_output_segment(elfcpp::PT_GNU_STACK, flags);
+ }
+}
+
+// Return whether SEG1 should be before SEG2 in the output file. This
+// is based entirely on the segment type and flags. When this is
+// called the segment addresses has normally not yet been set.
+
+bool
+Layout::segment_precedes(const Output_segment* seg1,
+ const Output_segment* seg2)
+{
+ elfcpp::Elf_Word type1 = seg1->type();
+ elfcpp::Elf_Word type2 = seg2->type();
+
+ // The single PT_PHDR segment is required to precede any loadable
+ // segment. We simply make it always first.
+ if (type1 == elfcpp::PT_PHDR)
+ {
+ gold_assert(type2 != elfcpp::PT_PHDR);
+ return true;
+ }
+ if (type2 == elfcpp::PT_PHDR)
+ return false;
+
+ // The single PT_INTERP segment is required to precede any loadable
+ // segment. We simply make it always second.
+ if (type1 == elfcpp::PT_INTERP)
+ {
+ gold_assert(type2 != elfcpp::PT_INTERP);
+ return true;
+ }
+ if (type2 == elfcpp::PT_INTERP)
+ return false;
+
+ // We then put PT_LOAD segments before any other segments.
if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD)
return true;
if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
{
if (type1 != type2)
return type1 < type2;
- assert(flags1 != flags2);
+ gold_assert(flags1 != flags2);
return flags1 < flags2;
}
+ // If the addresses are set already, sort by load address.
+ if (seg1->are_addresses_set())
+ {
+ if (!seg2->are_addresses_set())
+ return true;
+
+ unsigned int section_count1 = seg1->output_section_count();
+ unsigned int section_count2 = seg2->output_section_count();
+ if (section_count1 == 0 && section_count2 > 0)
+ return true;
+ if (section_count1 > 0 && section_count2 == 0)
+ return false;
+
+ uint64_t paddr1 = seg1->first_section_load_address();
+ uint64_t paddr2 = seg2->first_section_load_address();
+ if (paddr1 != paddr2)
+ return paddr1 < paddr2;
+ }
+ else if (seg2->are_addresses_set())
+ return false;
+
// We sort PT_LOAD segments based on the flags. Readonly segments
- // come before writable segments. Then executable segments come
- // before non-executable segments. Then the unlikely case of a
- // non-readable segment comes before the normal case of a readable
- // segment. If there are multiple segments with the same type and
- // flags, we require that the address be set, and we sort by
- // virtual address and then physical address.
+ // come before writable segments. Then writable segments with data
+ // come before writable segments without data. Then executable
+ // segments come before non-executable segments. Then the unlikely
+ // case of a non-readable segment comes before the normal case of a
+ // readable segment. If there are multiple segments with the same
+ // type and flags, we require that the address be set, and we sort
+ // by virtual address and then physical address.
if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W))
return (flags1 & elfcpp::PF_W) == 0;
+ if ((flags1 & elfcpp::PF_W) != 0
+ && seg1->has_any_data_sections() != seg2->has_any_data_sections())
+ return seg1->has_any_data_sections();
if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X))
return (flags1 & elfcpp::PF_X) != 0;
if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R))
return (flags1 & elfcpp::PF_R) == 0;
- uint64_t vaddr1 = seg1->vaddr();
- uint64_t vaddr2 = seg2->vaddr();
- if (vaddr1 != vaddr2)
- return vaddr1 < vaddr2;
-
- uint64_t paddr1 = seg1->paddr();
- uint64_t paddr2 = seg2->paddr();
- assert(paddr1 != paddr2);
- return paddr1 < paddr2;
+ // We shouldn't get here--we shouldn't create segments which we
+ // can't distinguish.
+ gold_unreachable();
}
// Set the file offsets of all the segments, and all the sections they
// Find the PT_LOAD segments, and set their addresses and offsets
// and their section's addresses and offsets.
- uint64_t addr = target->text_segment_address();
+ uint64_t addr;
+ if (this->options_.user_set_Ttext())
+ addr = this->options_.Ttext();
+ else if (parameters->options().shared())
+ addr = 0;
+ else
+ addr = target->default_text_segment_address();
off_t off = 0;
+
+ // If LOAD_SEG is NULL, then the file header and segment headers
+ // will not be loadable. But they still need to be at offset 0 in
+ // the file. Set their offsets now.
+ if (load_seg == NULL)
+ {
+ for (Data_list::iterator p = this->special_output_list_.begin();
+ p != this->special_output_list_.end();
+ ++p)
+ {
+ off = align_address(off, (*p)->addralign());
+ (*p)->set_address_and_file_offset(0, off);
+ off += (*p)->data_size();
+ }
+ }
+
bool was_readonly = false;
for (Segment_list::iterator p = this->segment_list_.begin();
p != this->segment_list_.end();
if ((*p)->type() == elfcpp::PT_LOAD)
{
if (load_seg != NULL && load_seg != *p)
- abort();
+ gold_unreachable();
load_seg = NULL;
- // If the last segment was readonly, and this one is not,
- // then skip the address forward one page, maintaining the
- // same position within the page. This lets us store both
- // segments overlapping on a single page in the file, but
- // the loader will put them on different pages in memory.
+ bool are_addresses_set = (*p)->are_addresses_set();
+ if (are_addresses_set)
+ {
+ // When it comes to setting file offsets, we care about
+ // the physical address.
+ addr = (*p)->paddr();
+ }
+ else if (this->options_.user_set_Tdata()
+ && ((*p)->flags() & elfcpp::PF_W) != 0
+ && (!this->options_.user_set_Tbss()
+ || (*p)->has_any_data_sections()))
+ {
+ addr = this->options_.Tdata();
+ are_addresses_set = true;
+ }
+ else if (this->options_.user_set_Tbss()
+ && ((*p)->flags() & elfcpp::PF_W) != 0
+ && !(*p)->has_any_data_sections())
+ {
+ addr = this->options_.Tbss();
+ are_addresses_set = true;
+ }
uint64_t orig_addr = addr;
uint64_t orig_off = off;
- uint64_t aligned_addr = addr;
+ uint64_t aligned_addr = 0;
uint64_t abi_pagesize = target->abi_pagesize();
- if (was_readonly && ((*p)->flags() & elfcpp::PF_W) != 0)
- {
- uint64_t align = (*p)->addralign();
- addr = align_address(addr, align);
+ // FIXME: This should depend on the -n and -N options.
+ (*p)->set_minimum_p_align(target->common_pagesize());
+
+ if (are_addresses_set)
+ {
+ // Adjust the file offset to the same address modulo the
+ // page size.
+ uint64_t unsigned_off = off;
+ uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1))
+ | (addr & (abi_pagesize - 1)));
+ if (aligned_off < unsigned_off)
+ aligned_off += abi_pagesize;
+ off = aligned_off;
+ }
+ else
+ {
+ // If the last segment was readonly, and this one is
+ // not, then skip the address forward one page,
+ // maintaining the same position within the page. This
+ // lets us store both segments overlapping on a single
+ // page in the file, but the loader will put them on
+ // different pages in memory.
+
+ addr = align_address(addr, (*p)->maximum_alignment());
aligned_addr = addr;
- if ((addr & (abi_pagesize - 1)) != 0)
- addr = addr + abi_pagesize;
+
+ if (was_readonly && ((*p)->flags() & elfcpp::PF_W) != 0)
+ {
+ if ((addr & (abi_pagesize - 1)) != 0)
+ addr = addr + abi_pagesize;
+ }
+
+ off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
}
unsigned int shndx_hold = *pshndx;
- off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
- uint64_t new_addr = (*p)->set_section_addresses(addr, &off, pshndx);
+ uint64_t new_addr = (*p)->set_section_addresses(false, addr, &off,
+ pshndx);
// Now that we know the size of this segment, we may be able
// to save a page in memory, at the cost of wasting some
// page. Here we use the real machine page size rather than
// the ABI mandated page size.
- if (aligned_addr != addr)
+ if (!are_addresses_set && aligned_addr != addr)
{
uint64_t common_pagesize = target->common_pagesize();
uint64_t first_off = (common_pagesize
{
*pshndx = shndx_hold;
addr = align_address(aligned_addr, common_pagesize);
+ addr = align_address(addr, (*p)->maximum_alignment());
off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
- new_addr = (*p)->set_section_addresses(addr, &off, pshndx);
+ new_addr = (*p)->set_section_addresses(true, addr, &off,
+ pshndx);
}
}
(*p)->set_offset();
}
+ // Set the TLS offsets for each section in the PT_TLS segment.
+ if (this->tls_segment_ != NULL)
+ this->tls_segment_->set_tls_offsets();
+
return off;
}
-// Set the file offset of all the sections not associated with a
-// segment.
+// Set the offsets of all the allocated sections when doing a
+// relocatable link. This does the same jobs as set_segment_offsets,
+// only for a relocatable link.
off_t
-Layout::set_section_offsets(off_t off, unsigned int* pshndx)
+Layout::set_relocatable_section_offsets(Output_data* file_header,
+ unsigned int *pshndx)
{
- for (Layout::Section_list::iterator p = this->section_list_.begin();
+ off_t off = 0;
+
+ file_header->set_address_and_file_offset(0, 0);
+ off += file_header->data_size();
+
+ for (Section_list::iterator p = this->section_list_.begin();
p != this->section_list_.end();
++p)
{
+ // We skip unallocated sections here, except that group sections
+ // have to come first.
+ if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0
+ && (*p)->type() != elfcpp::SHT_GROUP)
+ continue;
+
+ off = align_address(off, (*p)->addralign());
+
+ // The linker script might have set the address.
+ if (!(*p)->is_address_valid())
+ (*p)->set_address(0);
+ (*p)->set_file_offset(off);
+ (*p)->finalize_data_size();
+ off += (*p)->data_size();
+
(*p)->set_out_shndx(*pshndx);
++*pshndx;
- if ((*p)->offset() != -1)
+ }
+
+ return off;
+}
+
+// Set the file offset of all the sections not associated with a
+// segment.
+
+off_t
+Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
+{
+ for (Section_list::iterator p = this->unattached_section_list_.begin();
+ p != this->unattached_section_list_.end();
+ ++p)
+ {
+ // The symtab section is handled in create_symtab_sections.
+ if (*p == this->symtab_section_)
+ continue;
+
+ // If we've already set the data size, don't set it again.
+ if ((*p)->is_offset_valid() && (*p)->is_data_size_valid())
continue;
+
+ if (pass == BEFORE_INPUT_SECTIONS_PASS
+ && (*p)->requires_postprocessing())
+ {
+ (*p)->create_postprocessing_buffer();
+ this->any_postprocessing_sections_ = true;
+ }
+
+ if (pass == BEFORE_INPUT_SECTIONS_PASS
+ && (*p)->after_input_sections())
+ continue;
+ else if (pass == POSTPROCESSING_SECTIONS_PASS
+ && (!(*p)->after_input_sections()
+ || (*p)->type() == elfcpp::SHT_STRTAB))
+ continue;
+ else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS
+ && (!(*p)->after_input_sections()
+ || (*p)->type() != elfcpp::SHT_STRTAB))
+ continue;
+
off = align_address(off, (*p)->addralign());
- (*p)->set_address(0, off);
+ (*p)->set_file_offset(off);
+ (*p)->finalize_data_size();
off += (*p)->data_size();
+
+ // At this point the name must be set.
+ if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
+ this->namepool_.add((*p)->name(), false, NULL);
}
return off;
}
-// Create the symbol table sections.
+// Set the section indexes of all the sections not associated with a
+// segment.
+
+unsigned int
+Layout::set_section_indexes(unsigned int shndx)
+{
+ const bool output_is_object = parameters->options().relocatable();
+ for (Section_list::iterator p = this->unattached_section_list_.begin();
+ p != this->unattached_section_list_.end();
+ ++p)
+ {
+ // In a relocatable link, we already did group sections.
+ if (output_is_object
+ && (*p)->type() == elfcpp::SHT_GROUP)
+ continue;
+
+ (*p)->set_out_shndx(shndx);
+ ++shndx;
+ }
+ return shndx;
+}
+
+// Set the section addresses according to the linker script. This is
+// only called when we see a SECTIONS clause. This returns the
+// program segment which should hold the file header and segment
+// headers, if any. It will return NULL if they should not be in a
+// segment.
+
+Output_segment*
+Layout::set_section_addresses_from_script(Symbol_table* symtab)
+{
+ Script_sections* ss = this->script_options_->script_sections();
+ gold_assert(ss->saw_sections_clause());
+
+ // Place each orphaned output section in the script.
+ for (Section_list::iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
+ ++p)
+ {
+ if (!(*p)->found_in_sections_clause())
+ ss->place_orphan(*p);
+ }
+
+ return this->script_options_->set_section_addresses(symtab, this);
+}
+
+// Count the local symbols in the regular symbol table and the dynamic
+// symbol table, and build the respective string pools.
+
+void
+Layout::count_local_symbols(const Task* task,
+ const Input_objects* input_objects)
+{
+ // First, figure out an upper bound on the number of symbols we'll
+ // be inserting into each pool. This helps us create the pools with
+ // the right size, to avoid unnecessary hashtable resizing.
+ unsigned int symbol_count = 0;
+ for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
+ p != input_objects->relobj_end();
+ ++p)
+ symbol_count += (*p)->local_symbol_count();
+
+ // Go from "upper bound" to "estimate." We overcount for two
+ // reasons: we double-count symbols that occur in more than one
+ // object file, and we count symbols that are dropped from the
+ // output. Add it all together and assume we overcount by 100%.
+ symbol_count /= 2;
+
+ // We assume all symbols will go into both the sympool and dynpool.
+ this->sympool_.reserve(symbol_count);
+ this->dynpool_.reserve(symbol_count);
+
+ for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
+ p != input_objects->relobj_end();
+ ++p)
+ {
+ Task_lock_obj<Object> tlo(task, *p);
+ (*p)->count_local_symbols(&this->sympool_, &this->dynpool_);
+ }
+}
+
+// Create the symbol table sections. Here we also set the final
+// values of the symbols. At this point all the loadable sections are
+// fully laid out.
void
-Layout::create_symtab_sections(int size, const Input_objects* input_objects,
+Layout::create_symtab_sections(const Input_objects* input_objects,
Symbol_table* symtab,
- off_t* poff,
- Output_section** posymtab,
- Output_section** postrtab)
+ off_t* poff)
{
int symsize;
unsigned int align;
- if (size == 32)
+ if (parameters->target().get_size() == 32)
{
symsize = elfcpp::Elf_sizes<32>::sym_size;
align = 4;
}
- else if (size == 64)
+ else if (parameters->target().get_size() == 64)
{
symsize = elfcpp::Elf_sizes<64>::sym_size;
align = 8;
}
else
- abort();
+ gold_unreachable();
off_t off = *poff;
off = align_address(off, align);
off += symsize;
unsigned int local_symbol_index = 1;
+ // Add STT_SECTION symbols for each Output section which needs one.
+ for (Section_list::iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
+ ++p)
+ {
+ if (!(*p)->needs_symtab_index())
+ (*p)->set_symtab_index(-1U);
+ else
+ {
+ (*p)->set_symtab_index(local_symbol_index);
+ ++local_symbol_index;
+ off += symsize;
+ }
+ }
+
for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
p != input_objects->relobj_end();
++p)
{
- Task_lock_obj<Object> tlo(**p);
unsigned int index = (*p)->finalize_local_symbols(local_symbol_index,
- off,
- &this->sympool_);
+ off);
off += (index - local_symbol_index) * symsize;
local_symbol_index = index;
}
unsigned int local_symcount = local_symbol_index;
- assert(local_symcount * symsize == off - startoff);
+ gold_assert(local_symcount * symsize == off - startoff);
+
+ off_t dynoff;
+ size_t dyn_global_index;
+ size_t dyncount;
+ if (this->dynsym_section_ == NULL)
+ {
+ dynoff = 0;
+ dyn_global_index = 0;
+ dyncount = 0;
+ }
+ else
+ {
+ dyn_global_index = this->dynsym_section_->info();
+ off_t locsize = dyn_global_index * this->dynsym_section_->entsize();
+ dynoff = this->dynsym_section_->offset() + locsize;
+ dyncount = (this->dynsym_section_->data_size() - locsize) / symsize;
+ gold_assert(static_cast<off_t>(dyncount * symsize)
+ == this->dynsym_section_->data_size() - locsize);
+ }
+
+ off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
+ &this->sympool_, &local_symcount);
- off = symtab->finalize(local_symcount, off, &this->sympool_);
+ if (!parameters->options().strip_all())
+ {
+ this->sympool_.set_string_offsets();
- this->sympool_.set_string_offsets();
+ const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
+ Output_section* osymtab = this->make_output_section(symtab_name,
+ elfcpp::SHT_SYMTAB,
+ 0);
+ this->symtab_section_ = osymtab;
- const char* symtab_name = this->namepool_.add(".symtab", NULL);
- Output_section* osymtab = new Output_section_symtab(symtab_name,
- off - startoff);
- this->section_list_.push_back(osymtab);
+ Output_section_data* pos = new Output_data_fixed_space(off - startoff,
+ align);
+ osymtab->add_output_section_data(pos);
- const char* strtab_name = this->namepool_.add(".strtab", NULL);
- Output_section *ostrtab = new Output_section_strtab(strtab_name,
- &this->sympool_);
- this->section_list_.push_back(ostrtab);
- this->special_output_list_.push_back(ostrtab);
+ const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
+ Output_section* ostrtab = this->make_output_section(strtab_name,
+ elfcpp::SHT_STRTAB,
+ 0);
- osymtab->set_address(0, startoff);
- osymtab->set_info(local_symcount);
- osymtab->set_entsize(symsize);
- osymtab->set_addralign(align);
+ Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
+ ostrtab->add_output_section_data(pstr);
- *poff = off;
- *posymtab = osymtab;
- *postrtab = ostrtab;
+ osymtab->set_file_offset(startoff);
+ osymtab->finalize_data_size();
+ osymtab->set_link_section(ostrtab);
+ osymtab->set_info(local_symcount);
+ osymtab->set_entsize(symsize);
+
+ *poff = off;
+ }
}
// Create the .shstrtab section, which holds the names of the
// FIXME: We don't need to create a .shstrtab section if we are
// stripping everything.
- const char* name = this->namepool_.add(".shstrtab", NULL);
+ const char* name = this->namepool_.add(".shstrtab", false, NULL);
- this->namepool_.set_string_offsets();
+ Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0);
- Output_section* os = new Output_section_strtab(name, &this->namepool_);
+ // We can't write out this section until we've set all the section
+ // names, and we don't set the names of compressed output sections
+ // until relocations are complete.
+ os->set_after_input_sections();
- this->section_list_.push_back(os);
- this->special_output_list_.push_back(os);
+ Output_section_data* posd = new Output_data_strtab(&this->namepool_);
+ os->add_output_section_data(posd);
return os;
}
// Create the section headers. SIZE is 32 or 64. OFF is the file
// offset.
-Output_section_headers*
-Layout::create_shdrs(int size, bool big_endian, off_t* poff)
+void
+Layout::create_shdrs(off_t* poff)
{
Output_section_headers* oshdrs;
- oshdrs = new Output_section_headers(size, big_endian, this->segment_list_,
- this->section_list_,
+ oshdrs = new Output_section_headers(this,
+ &this->segment_list_,
+ &this->section_list_,
+ &this->unattached_section_list_,
&this->namepool_);
off_t off = align_address(*poff, oshdrs->addralign());
- oshdrs->set_address(0, off);
+ oshdrs->set_address_and_file_offset(0, off);
off += oshdrs->data_size();
*poff = off;
- this->special_output_list_.push_back(oshdrs);
- return oshdrs;
+ this->section_headers_ = oshdrs;
}
// Create the dynamic symbol table.
void
-Layout::create_dynamic_symtab(int, Symbol_table*)
+Layout::create_dynamic_symtab(const Input_objects* input_objects,
+ Symbol_table* symtab,
+ Output_section **pdynstr,
+ unsigned int* plocal_dynamic_count,
+ std::vector<Symbol*>* pdynamic_symbols,
+ Versions* pversions)
{
- abort();
+ // Count all the symbols in the dynamic symbol table, and set the
+ // dynamic symbol indexes.
+
+ // Skip symbol 0, which is always all zeroes.
+ unsigned int index = 1;
+
+ // Add STT_SECTION symbols for each Output section which needs one.
+ for (Section_list::iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
+ ++p)
+ {
+ if (!(*p)->needs_dynsym_index())
+ (*p)->set_dynsym_index(-1U);
+ else
+ {
+ (*p)->set_dynsym_index(index);
+ ++index;
+ }
+ }
+
+ // Count the local symbols that need to go in the dynamic symbol table,
+ // and set the dynamic symbol indexes.
+ for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
+ p != input_objects->relobj_end();
+ ++p)
+ {
+ unsigned int new_index = (*p)->set_local_dynsym_indexes(index);
+ index = new_index;
+ }
+
+ unsigned int local_symcount = index;
+ *plocal_dynamic_count = local_symcount;
+
+ // FIXME: We have to tell set_dynsym_indexes whether the
+ // -E/--export-dynamic option was used.
+ index = symtab->set_dynsym_indexes(index, pdynamic_symbols,
+ &this->dynpool_, pversions);
+
+ int symsize;
+ unsigned int align;
+ const int size = parameters->target().get_size();
+ if (size == 32)
+ {
+ symsize = elfcpp::Elf_sizes<32>::sym_size;
+ align = 4;
+ }
+ else if (size == 64)
+ {
+ symsize = elfcpp::Elf_sizes<64>::sym_size;
+ align = 8;
+ }
+ else
+ gold_unreachable();
+
+ // Create the dynamic symbol table section.
+
+ Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
+ elfcpp::SHT_DYNSYM,
+ elfcpp::SHF_ALLOC,
+ false);
+
+ Output_section_data* odata = new Output_data_fixed_space(index * symsize,
+ align);
+ dynsym->add_output_section_data(odata);
+
+ dynsym->set_info(local_symcount);
+ dynsym->set_entsize(symsize);
+ dynsym->set_addralign(align);
+
+ this->dynsym_section_ = dynsym;
+
+ Output_data_dynamic* const odyn = this->dynamic_data_;
+ odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
+ odyn->add_constant(elfcpp::DT_SYMENT, symsize);
+
+ // Create the dynamic string table section.
+
+ Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
+ elfcpp::SHT_STRTAB,
+ elfcpp::SHF_ALLOC,
+ false);
+
+ Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
+ dynstr->add_output_section_data(strdata);
+
+ dynsym->set_link_section(dynstr);
+ this->dynamic_section_->set_link_section(dynstr);
+
+ odyn->add_section_address(elfcpp::DT_STRTAB, dynstr);
+ odyn->add_section_size(elfcpp::DT_STRSZ, dynstr);
+
+ *pdynstr = dynstr;
+
+ // Create the hash tables.
+
+ // FIXME: We need an option to create a GNU hash table.
+
+ unsigned char* phash;
+ unsigned int hashlen;
+ Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
+ &phash, &hashlen);
+
+ Output_section* hashsec = this->choose_output_section(NULL, ".hash",
+ elfcpp::SHT_HASH,
+ elfcpp::SHF_ALLOC,
+ false);
+
+ Output_section_data* hashdata = new Output_data_const_buffer(phash,
+ hashlen,
+ align);
+ hashsec->add_output_section_data(hashdata);
+
+ hashsec->set_link_section(dynsym);
+ hashsec->set_entsize(4);
+
+ odyn->add_section_address(elfcpp::DT_HASH, hashsec);
}
-// Create the .dynamic section and PT_DYNAMIC segment.
+// Assign offsets to each local portion of the dynamic symbol table.
void
-Layout::create_dynamic_section()
+Layout::assign_local_dynsym_offsets(const Input_objects* input_objects)
{
- abort();
+ Output_section* dynsym = this->dynsym_section_;
+ gold_assert(dynsym != NULL);
+
+ off_t off = dynsym->offset();
+
+ // Skip the dummy symbol at the start of the section.
+ off += dynsym->entsize();
+
+ for (Input_objects::Relobj_iterator p = input_objects->relobj_begin();
+ p != input_objects->relobj_end();
+ ++p)
+ {
+ unsigned int count = (*p)->set_local_dynsym_offset(off);
+ off += count * dynsym->entsize();
+ }
+}
+
+// Create the version sections.
+
+void
+Layout::create_version_sections(const Versions* versions,
+ const Symbol_table* symtab,
+ unsigned int local_symcount,
+ const std::vector<Symbol*>& dynamic_symbols,
+ const Output_section* dynstr)
+{
+ if (!versions->any_defs() && !versions->any_needs())
+ return;
+
+ switch (parameters->size_and_endianness())
+ {
+#ifdef HAVE_TARGET_32_LITTLE
+ case Parameters::TARGET_32_LITTLE:
+ this->sized_create_version_sections<32, false>(versions, symtab,
+ local_symcount,
+ dynamic_symbols, dynstr);
+ break;
+#endif
+#ifdef HAVE_TARGET_32_BIG
+ case Parameters::TARGET_32_BIG:
+ this->sized_create_version_sections<32, true>(versions, symtab,
+ local_symcount,
+ dynamic_symbols, dynstr);
+ break;
+#endif
+#ifdef HAVE_TARGET_64_LITTLE
+ case Parameters::TARGET_64_LITTLE:
+ this->sized_create_version_sections<64, false>(versions, symtab,
+ local_symcount,
+ dynamic_symbols, dynstr);
+ break;
+#endif
+#ifdef HAVE_TARGET_64_BIG
+ case Parameters::TARGET_64_BIG:
+ this->sized_create_version_sections<64, true>(versions, symtab,
+ local_symcount,
+ dynamic_symbols, dynstr);
+ break;
+#endif
+ default:
+ gold_unreachable();
+ }
+}
+
+// Create the version sections, sized version.
+
+template<int size, bool big_endian>
+void
+Layout::sized_create_version_sections(
+ const Versions* versions,
+ const Symbol_table* symtab,
+ unsigned int local_symcount,
+ const std::vector<Symbol*>& dynamic_symbols,
+ const Output_section* dynstr)
+{
+ Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
+ elfcpp::SHT_GNU_versym,
+ elfcpp::SHF_ALLOC,
+ false);
+
+ unsigned char* vbuf;
+ unsigned int vsize;
+ versions->symbol_section_contents<size, big_endian>(symtab, &this->dynpool_,
+ local_symcount,
+ dynamic_symbols,
+ &vbuf, &vsize);
+
+ Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2);
+
+ vsec->add_output_section_data(vdata);
+ vsec->set_entsize(2);
+ vsec->set_link_section(this->dynsym_section_);
+
+ Output_data_dynamic* const odyn = this->dynamic_data_;
+ odyn->add_section_address(elfcpp::DT_VERSYM, vsec);
+
+ if (versions->any_defs())
+ {
+ Output_section* vdsec;
+ vdsec= this->choose_output_section(NULL, ".gnu.version_d",
+ elfcpp::SHT_GNU_verdef,
+ elfcpp::SHF_ALLOC,
+ false);
+
+ unsigned char* vdbuf;
+ unsigned int vdsize;
+ unsigned int vdentries;
+ versions->def_section_contents<size, big_endian>(&this->dynpool_, &vdbuf,
+ &vdsize, &vdentries);
+
+ Output_section_data* vddata = new Output_data_const_buffer(vdbuf,
+ vdsize,
+ 4);
+
+ vdsec->add_output_section_data(vddata);
+ vdsec->set_link_section(dynstr);
+ vdsec->set_info(vdentries);
+
+ odyn->add_section_address(elfcpp::DT_VERDEF, vdsec);
+ odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries);
+ }
+
+ if (versions->any_needs())
+ {
+ Output_section* vnsec;
+ vnsec = this->choose_output_section(NULL, ".gnu.version_r",
+ elfcpp::SHT_GNU_verneed,
+ elfcpp::SHF_ALLOC,
+ false);
+
+ unsigned char* vnbuf;
+ unsigned int vnsize;
+ unsigned int vnentries;
+ versions->need_section_contents<size, big_endian>(&this->dynpool_,
+ &vnbuf, &vnsize,
+ &vnentries);
+
+ Output_section_data* vndata = new Output_data_const_buffer(vnbuf,
+ vnsize,
+ 4);
+
+ vnsec->add_output_section_data(vndata);
+ vnsec->set_link_section(dynstr);
+ vnsec->set_info(vnentries);
+
+ odyn->add_section_address(elfcpp::DT_VERNEED, vnsec);
+ odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries);
+ }
}
// Create the .interp section and PT_INTERP segment.
if (interp == NULL)
{
interp = target->dynamic_linker();
- assert(interp != NULL);
+ gold_assert(interp != NULL);
}
size_t len = strlen(interp) + 1;
Output_section_data* odata = new Output_data_const(interp, len, 1);
- const char* interp_name = this->namepool_.add(".interp", NULL);
- Output_section* osec = this->make_output_section(interp_name,
- elfcpp::SHT_PROGBITS,
- elfcpp::SHF_ALLOC);
+ Output_section* osec = this->choose_output_section(NULL, ".interp",
+ elfcpp::SHT_PROGBITS,
+ elfcpp::SHF_ALLOC,
+ false);
osec->add_output_section_data(odata);
- Output_segment* oseg = new Output_segment(elfcpp::PT_INTERP, elfcpp::PF_R);
- this->segment_list_.push_back(oseg);
- oseg->add_initial_output_section(osec, elfcpp::PF_R);
+ if (!this->script_options_->saw_phdrs_clause())
+ {
+ Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
+ elfcpp::PF_R);
+ oseg->add_initial_output_section(osec, elfcpp::PF_R);
+ }
+}
+
+// Finish the .dynamic section and PT_DYNAMIC segment.
+
+void
+Layout::finish_dynamic_section(const Input_objects* input_objects,
+ const Symbol_table* symtab)
+{
+ if (!this->script_options_->saw_phdrs_clause())
+ {
+ Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC,
+ (elfcpp::PF_R
+ | elfcpp::PF_W));
+ oseg->add_initial_output_section(this->dynamic_section_,
+ elfcpp::PF_R | elfcpp::PF_W);
+ }
+
+ Output_data_dynamic* const odyn = this->dynamic_data_;
+
+ for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin();
+ p != input_objects->dynobj_end();
+ ++p)
+ {
+ // FIXME: Handle --as-needed.
+ odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname());
+ }
+
+ if (parameters->options().shared())
+ {
+ const char* soname = this->options_.soname();
+ if (soname != NULL)
+ odyn->add_string(elfcpp::DT_SONAME, soname);
+ }
+
+ // FIXME: Support --init and --fini.
+ Symbol* sym = symtab->lookup("_init");
+ if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
+ odyn->add_symbol(elfcpp::DT_INIT, sym);
+
+ sym = symtab->lookup("_fini");
+ if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj())
+ odyn->add_symbol(elfcpp::DT_FINI, sym);
+
+ // FIXME: Support DT_INIT_ARRAY and DT_FINI_ARRAY.
+
+ // Add a DT_RPATH entry if needed.
+ const General_options::Dir_list& rpath(this->options_.rpath());
+ if (!rpath.empty())
+ {
+ std::string rpath_val;
+ for (General_options::Dir_list::const_iterator p = rpath.begin();
+ p != rpath.end();
+ ++p)
+ {
+ if (rpath_val.empty())
+ rpath_val = p->name();
+ else
+ {
+ // Eliminate duplicates.
+ General_options::Dir_list::const_iterator q;
+ for (q = rpath.begin(); q != p; ++q)
+ if (q->name() == p->name())
+ break;
+ if (q == p)
+ {
+ rpath_val += ':';
+ rpath_val += p->name();
+ }
+ }
+ }
+
+ odyn->add_string(elfcpp::DT_RPATH, rpath_val);
+ }
+
+ // Look for text segments that have dynamic relocations.
+ bool have_textrel = false;
+ if (!this->script_options_->saw_sections_clause())
+ {
+ for (Segment_list::const_iterator p = this->segment_list_.begin();
+ p != this->segment_list_.end();
+ ++p)
+ {
+ if (((*p)->flags() & elfcpp::PF_W) == 0
+ && (*p)->dynamic_reloc_count() > 0)
+ {
+ have_textrel = true;
+ break;
+ }
+ }
+ }
+ else
+ {
+ // We don't know the section -> segment mapping, so we are
+ // conservative and just look for readonly sections with
+ // relocations. If those sections wind up in writable segments,
+ // then we have created an unnecessary DT_TEXTREL entry.
+ for (Section_list::const_iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
+ ++p)
+ {
+ if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0
+ && ((*p)->flags() & elfcpp::SHF_WRITE) == 0
+ && ((*p)->dynamic_reloc_count() > 0))
+ {
+ have_textrel = true;
+ break;
+ }
+ }
+ }
+
+ // Add a DT_FLAGS entry. We add it even if no flags are set so that
+ // post-link tools can easily modify these flags if desired.
+ unsigned int flags = 0;
+ if (have_textrel)
+ {
+ // Add a DT_TEXTREL for compatibility with older loaders.
+ odyn->add_constant(elfcpp::DT_TEXTREL, 0);
+ flags |= elfcpp::DF_TEXTREL;
+ }
+ if (parameters->options().shared() && this->has_static_tls())
+ flags |= elfcpp::DF_STATIC_TLS;
+ odyn->add_constant(elfcpp::DT_FLAGS, flags);
}
// The mapping of .gnu.linkonce section names to real section names.
return Layout::linkonce_output_name(name, plen);
}
- // If the section name has no '.', or only an initial '.', we use
- // the name unchanged (i.e., ".text" is unchanged).
-
- // Otherwise, if the section name does not include ".rel", we drop
- // the last '.' and everything that follows (i.e., ".text.XXX"
- // becomes ".text").
-
- // Otherwise, if the section name has zero or one '.' after the
- // ".rel", we use the name unchanged (i.e., ".rel.text" is
- // unchanged).
-
- // Otherwise, we drop the last '.' and everything that follows
- // (i.e., ".rel.text.XXX" becomes ".rel.text").
+ // gcc 4.3 generates the following sorts of section names when it
+ // needs a section name specific to a function:
+ // .text.FN
+ // .rodata.FN
+ // .sdata2.FN
+ // .data.FN
+ // .data.rel.FN
+ // .data.rel.local.FN
+ // .data.rel.ro.FN
+ // .data.rel.ro.local.FN
+ // .sdata.FN
+ // .bss.FN
+ // .sbss.FN
+ // .tdata.FN
+ // .tbss.FN
+
+ // The GNU linker maps all of those to the part before the .FN,
+ // except that .data.rel.local.FN is mapped to .data, and
+ // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections
+ // beginning with .data.rel.ro.local are grouped together.
+
+ // For an anonymous namespace, the string FN can contain a '.'.
+
+ // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the
+ // GNU linker maps to .rodata.
+
+ // The .data.rel.ro sections enable a security feature triggered by
+ // the -z relro option. Section which need to be relocated at
+ // program startup time but which may be readonly after startup are
+ // grouped into .data.rel.ro. They are then put into a PT_GNU_RELRO
+ // segment. The dynamic linker will make that segment writable,
+ // perform relocations, and then make it read-only. FIXME: We do
+ // not yet implement this optimization.
+
+ // It is hard to handle this in a principled way.
+
+ // These are the rules we follow:
+
+ // If the section name has no initial '.', or no dot other than an
+ // initial '.', we use the name unchanged (i.e., "mysection" and
+ // ".text" are unchanged).
+
+ // If the name starts with ".data.rel.ro" we use ".data.rel.ro".
+
+ // Otherwise, we drop the second '.' and everything that comes after
+ // it (i.e., ".text.XXX" becomes ".text").
const char* s = name;
- if (*s == '.')
- ++s;
+ if (*s != '.')
+ return name;
+ ++s;
const char* sdot = strchr(s, '.');
if (sdot == NULL)
return name;
- const char* srel = strstr(s, ".rel");
- if (srel == NULL)
+ const char* const data_rel_ro = ".data.rel.ro";
+ if (strncmp(name, data_rel_ro, strlen(data_rel_ro)) == 0)
{
- *plen = sdot - name;
- return name;
+ *plen = strlen(data_rel_ro);
+ return data_rel_ro;
}
- sdot = strchr(srel + 1, '.');
- if (sdot == NULL)
- return name;
- sdot = strchr(sdot + 1, '.');
- if (sdot == NULL)
- return name;
-
*plen = sdot - name;
return name;
}
else if (group)
{
// This is a real section group, and we've already seen a
- // linkonce section with tihs signature. Record that we've seen
+ // linkonce section with this signature. Record that we've seen
// a section group, and don't include this section group.
ins.first->second = true;
return false;
}
}
+// Store the allocated sections into the section list.
+
+void
+Layout::get_allocated_sections(Section_list* section_list) const
+{
+ for (Section_list::const_iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
+ ++p)
+ if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0)
+ section_list->push_back(*p);
+}
+
+// Create an output segment.
+
+Output_segment*
+Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags)
+{
+ gold_assert(!parameters->options().relocatable());
+ Output_segment* oseg = new Output_segment(type, flags);
+ this->segment_list_.push_back(oseg);
+ return oseg;
+}
+
+// Write out the Output_sections. Most won't have anything to write,
+// since most of the data will come from input sections which are
+// handled elsewhere. But some Output_sections do have Output_data.
+
+void
+Layout::write_output_sections(Output_file* of) const
+{
+ for (Section_list::const_iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
+ ++p)
+ {
+ if (!(*p)->after_input_sections())
+ (*p)->write(of);
+ }
+}
+
// Write out data not associated with a section or the symbol table.
void
-Layout::write_data(Output_file* of) const
+Layout::write_data(const Symbol_table* symtab, Output_file* of) const
{
+ if (!parameters->options().strip_all())
+ {
+ const Output_section* symtab_section = this->symtab_section_;
+ for (Section_list::const_iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
+ ++p)
+ {
+ if ((*p)->needs_symtab_index())
+ {
+ gold_assert(symtab_section != NULL);
+ unsigned int index = (*p)->symtab_index();
+ gold_assert(index > 0 && index != -1U);
+ off_t off = (symtab_section->offset()
+ + index * symtab_section->entsize());
+ symtab->write_section_symbol(*p, of, off);
+ }
+ }
+ }
+
+ const Output_section* dynsym_section = this->dynsym_section_;
+ for (Section_list::const_iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
+ ++p)
+ {
+ if ((*p)->needs_dynsym_index())
+ {
+ gold_assert(dynsym_section != NULL);
+ unsigned int index = (*p)->dynsym_index();
+ gold_assert(index > 0 && index != -1U);
+ off_t off = (dynsym_section->offset()
+ + index * dynsym_section->entsize());
+ symtab->write_section_symbol(*p, of, off);
+ }
+ }
+
+ // Write out the Output_data which are not in an Output_section.
for (Data_list::const_iterator p = this->special_output_list_.begin();
p != this->special_output_list_.end();
++p)
(*p)->write(of);
}
+// Write out the Output_sections which can only be written after the
+// input sections are complete.
+
+void
+Layout::write_sections_after_input_sections(Output_file* of)
+{
+ // Determine the final section offsets, and thus the final output
+ // file size. Note we finalize the .shstrab last, to allow the
+ // after_input_section sections to modify their section-names before
+ // writing.
+ if (this->any_postprocessing_sections_)
+ {
+ off_t off = this->output_file_size_;
+ off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS);
+
+ // Now that we've finalized the names, we can finalize the shstrab.
+ off =
+ this->set_section_offsets(off,
+ STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS);
+
+ if (off > this->output_file_size_)
+ {
+ of->resize(off);
+ this->output_file_size_ = off;
+ }
+ }
+
+ for (Section_list::const_iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
+ ++p)
+ {
+ if ((*p)->after_input_sections())
+ (*p)->write(of);
+ }
+
+ this->section_headers_->write(of);
+}
+
+// Write out a binary file. This is called after the link is
+// complete. IN is the temporary output file we used to generate the
+// ELF code. We simply walk through the segments, read them from
+// their file offset in IN, and write them to their load address in
+// the output file. FIXME: with a bit more work, we could support
+// S-records and/or Intel hex format here.
+
+void
+Layout::write_binary(Output_file* in) const
+{
+ gold_assert(this->options_.oformat_enum()
+ == General_options::OBJECT_FORMAT_BINARY);
+
+ // Get the size of the binary file.
+ uint64_t max_load_address = 0;
+ for (Segment_list::const_iterator p = this->segment_list_.begin();
+ p != this->segment_list_.end();
+ ++p)
+ {
+ if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
+ {
+ uint64_t max_paddr = (*p)->paddr() + (*p)->filesz();
+ if (max_paddr > max_load_address)
+ max_load_address = max_paddr;
+ }
+ }
+
+ Output_file out(parameters->options().output_file_name());
+ out.open(max_load_address);
+
+ for (Segment_list::const_iterator p = this->segment_list_.begin();
+ p != this->segment_list_.end();
+ ++p)
+ {
+ if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0)
+ {
+ const unsigned char* vin = in->get_input_view((*p)->offset(),
+ (*p)->filesz());
+ unsigned char* vout = out.get_output_view((*p)->paddr(),
+ (*p)->filesz());
+ memcpy(vout, vin, (*p)->filesz());
+ out.write_output_view((*p)->paddr(), (*p)->filesz(), vout);
+ in->free_input_view((*p)->offset(), (*p)->filesz(), vin);
+ }
+ }
+
+ out.close();
+}
+
+// Print statistical information to stderr. This is used for --stats.
+
+void
+Layout::print_stats() const
+{
+ this->namepool_.print_stats("section name pool");
+ this->sympool_.print_stats("output symbol name pool");
+ this->dynpool_.print_stats("dynamic name pool");
+
+ for (Section_list::const_iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
+ ++p)
+ (*p)->print_merge_stats();
+}
+
+// Write_sections_task methods.
+
+// We can always run this task.
+
+Task_token*
+Write_sections_task::is_runnable()
+{
+ return NULL;
+}
+
+// We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER
+// when finished.
+
+void
+Write_sections_task::locks(Task_locker* tl)
+{
+ tl->add(this, this->output_sections_blocker_);
+ tl->add(this, this->final_blocker_);
+}
+
+// Run the task--write out the data.
+
+void
+Write_sections_task::run(Workqueue*)
+{
+ this->layout_->write_output_sections(this->of_);
+}
+
// Write_data_task methods.
// We can always run this task.
-Task::Is_runnable_type
-Write_data_task::is_runnable(Workqueue*)
+Task_token*
+Write_data_task::is_runnable()
{
- return IS_RUNNABLE;
+ return NULL;
}
// We need to unlock FINAL_BLOCKER when finished.
-Task_locker*
-Write_data_task::locks(Workqueue* workqueue)
+void
+Write_data_task::locks(Task_locker* tl)
{
- return new Task_locker_block(*this->final_blocker_, workqueue);
+ tl->add(this, this->final_blocker_);
}
// Run the task--write out the data.
void
Write_data_task::run(Workqueue*)
{
- this->layout_->write_data(this->of_);
+ this->layout_->write_data(this->symtab_, this->of_);
}
// Write_symbols_task methods.
// We can always run this task.
-Task::Is_runnable_type
-Write_symbols_task::is_runnable(Workqueue*)
+Task_token*
+Write_symbols_task::is_runnable()
{
- return IS_RUNNABLE;
+ return NULL;
}
// We need to unlock FINAL_BLOCKER when finished.
-Task_locker*
-Write_symbols_task::locks(Workqueue* workqueue)
+void
+Write_symbols_task::locks(Task_locker* tl)
{
- return new Task_locker_block(*this->final_blocker_, workqueue);
+ tl->add(this, this->final_blocker_);
}
// Run the task--write out the symbols.
void
Write_symbols_task::run(Workqueue*)
{
- this->symtab_->write_globals(this->target_, this->sympool_, this->of_);
+ this->symtab_->write_globals(this->input_objects_, this->sympool_,
+ this->dynpool_, this->of_);
+}
+
+// Write_after_input_sections_task methods.
+
+// We can only run this task after the input sections have completed.
+
+Task_token*
+Write_after_input_sections_task::is_runnable()
+{
+ if (this->input_sections_blocker_->is_blocked())
+ return this->input_sections_blocker_;
+ return NULL;
+}
+
+// We need to unlock FINAL_BLOCKER when finished.
+
+void
+Write_after_input_sections_task::locks(Task_locker* tl)
+{
+ tl->add(this, this->final_blocker_);
+}
+
+// Run the task.
+
+void
+Write_after_input_sections_task::run(Workqueue*)
+{
+ this->layout_->write_sections_after_input_sections(this->of_);
}
// Close_task_runner methods.
// Run the task--close the file.
void
-Close_task_runner::run(Workqueue*)
+Close_task_runner::run(Workqueue*, const Task*)
{
+ // If we've been asked to create a binary file, we do so here.
+ if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF)
+ this->layout_->write_binary(this->of_);
+
this->of_->close();
}
// Instantiate the templates we need. We could use the configure
// script to restrict this to only the ones for implemented targets.
+#ifdef HAVE_TARGET_32_LITTLE
template
Output_section*
-Layout::layout<32, false>(Relobj* object, unsigned int shndx, const char* name,
- const elfcpp::Shdr<32, false>& shdr, off_t*);
+Layout::layout<32, false>(Sized_relobj<32, false>* object, unsigned int shndx,
+ const char* name,
+ const elfcpp::Shdr<32, false>& shdr,
+ unsigned int, unsigned int, off_t*);
+#endif
+#ifdef HAVE_TARGET_32_BIG
template
Output_section*
-Layout::layout<32, true>(Relobj* object, unsigned int shndx, const char* name,
- const elfcpp::Shdr<32, true>& shdr, off_t*);
+Layout::layout<32, true>(Sized_relobj<32, true>* object, unsigned int shndx,
+ const char* name,
+ const elfcpp::Shdr<32, true>& shdr,
+ unsigned int, unsigned int, off_t*);
+#endif
+#ifdef HAVE_TARGET_64_LITTLE
template
Output_section*
-Layout::layout<64, false>(Relobj* object, unsigned int shndx, const char* name,
- const elfcpp::Shdr<64, false>& shdr, off_t*);
+Layout::layout<64, false>(Sized_relobj<64, false>* object, unsigned int shndx,
+ const char* name,
+ const elfcpp::Shdr<64, false>& shdr,
+ unsigned int, unsigned int, off_t*);
+#endif
+#ifdef HAVE_TARGET_64_BIG
template
Output_section*
-Layout::layout<64, true>(Relobj* object, unsigned int shndx, const char* name,
- const elfcpp::Shdr<64, true>& shdr, off_t*);
+Layout::layout<64, true>(Sized_relobj<64, true>* object, unsigned int shndx,
+ const char* name,
+ const elfcpp::Shdr<64, true>& shdr,
+ unsigned int, unsigned int, off_t*);
+#endif
+#ifdef HAVE_TARGET_32_LITTLE
+template
+Output_section*
+Layout::layout_reloc<32, false>(Sized_relobj<32, false>* object,
+ unsigned int reloc_shndx,
+ const elfcpp::Shdr<32, false>& shdr,
+ Output_section* data_section,
+ Relocatable_relocs* rr);
+#endif
+
+#ifdef HAVE_TARGET_32_BIG
+template
+Output_section*
+Layout::layout_reloc<32, true>(Sized_relobj<32, true>* object,
+ unsigned int reloc_shndx,
+ const elfcpp::Shdr<32, true>& shdr,
+ Output_section* data_section,
+ Relocatable_relocs* rr);
+#endif
+
+#ifdef HAVE_TARGET_64_LITTLE
+template
+Output_section*
+Layout::layout_reloc<64, false>(Sized_relobj<64, false>* object,
+ unsigned int reloc_shndx,
+ const elfcpp::Shdr<64, false>& shdr,
+ Output_section* data_section,
+ Relocatable_relocs* rr);
+#endif
+
+#ifdef HAVE_TARGET_64_BIG
+template
+Output_section*
+Layout::layout_reloc<64, true>(Sized_relobj<64, true>* object,
+ unsigned int reloc_shndx,
+ const elfcpp::Shdr<64, true>& shdr,
+ Output_section* data_section,
+ Relocatable_relocs* rr);
+#endif
+
+#ifdef HAVE_TARGET_32_LITTLE
+template
+void
+Layout::layout_group<32, false>(Symbol_table* symtab,
+ Sized_relobj<32, false>* object,
+ unsigned int,
+ const char* group_section_name,
+ const char* signature,
+ const elfcpp::Shdr<32, false>& shdr,
+ const elfcpp::Elf_Word* contents);
+#endif
+
+#ifdef HAVE_TARGET_32_BIG
+template
+void
+Layout::layout_group<32, true>(Symbol_table* symtab,
+ Sized_relobj<32, true>* object,
+ unsigned int,
+ const char* group_section_name,
+ const char* signature,
+ const elfcpp::Shdr<32, true>& shdr,
+ const elfcpp::Elf_Word* contents);
+#endif
+
+#ifdef HAVE_TARGET_64_LITTLE
+template
+void
+Layout::layout_group<64, false>(Symbol_table* symtab,
+ Sized_relobj<64, false>* object,
+ unsigned int,
+ const char* group_section_name,
+ const char* signature,
+ const elfcpp::Shdr<64, false>& shdr,
+ const elfcpp::Elf_Word* contents);
+#endif
+
+#ifdef HAVE_TARGET_64_BIG
+template
+void
+Layout::layout_group<64, true>(Symbol_table* symtab,
+ Sized_relobj<64, true>* object,
+ unsigned int,
+ const char* group_section_name,
+ const char* signature,
+ const elfcpp::Shdr<64, true>& shdr,
+ const elfcpp::Elf_Word* contents);
+#endif
+
+#ifdef HAVE_TARGET_32_LITTLE
+template
+Output_section*
+Layout::layout_eh_frame<32, false>(Sized_relobj<32, false>* 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<32, false>& shdr,
+ unsigned int reloc_shndx,
+ unsigned int reloc_type,
+ off_t* off);
+#endif
+
+#ifdef HAVE_TARGET_32_BIG
+template
+Output_section*
+Layout::layout_eh_frame<32, true>(Sized_relobj<32, true>* 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<32, true>& shdr,
+ unsigned int reloc_shndx,
+ unsigned int reloc_type,
+ off_t* off);
+#endif
+
+#ifdef HAVE_TARGET_64_LITTLE
+template
+Output_section*
+Layout::layout_eh_frame<64, false>(Sized_relobj<64, false>* 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<64, false>& shdr,
+ unsigned int reloc_shndx,
+ unsigned int reloc_type,
+ off_t* off);
+#endif
+
+#ifdef HAVE_TARGET_64_BIG
+template
+Output_section*
+Layout::layout_eh_frame<64, true>(Sized_relobj<64, true>* 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<64, true>& shdr,
+ unsigned int reloc_shndx,
+ unsigned int reloc_type,
+ off_t* off);
+#endif
} // End namespace gold.
projects / external / binutils.git / blobdiff