#include "gold.h"
+#include <cerrno>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <utility>
+#include <fcntl.h>
+#include <unistd.h>
+#include "libiberty.h"
+#include "md5.h"
+#include "sha1.h"
#include "parameters.h"
#include "options.h"
+#include "mapfile.h"
#include "script.h"
#include "script-sections.h"
#include "output.h"
#include "dynobj.h"
#include "ehframe.h"
#include "compressed_output.h"
+#include "reduced_debug_output.h"
#include "reloc.h"
+#include "descriptors.h"
#include "layout.h"
+#include "plugin.h"
namespace gold
{
// Now we know the final size of the output file and we know where
// each piece of information goes.
+
+ if (this->mapfile_ != NULL)
+ {
+ this->mapfile_->print_discarded_sections(this->input_objects_);
+ this->layout_->print_to_mapfile(this->mapfile_);
+ }
+
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();
// Layout methods.
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_(),
- 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),
+ : options_(options),
+ script_options_(script_options),
+ namepool_(),
+ sympool_(),
+ dynpool_(),
+ signatures_(),
+ section_name_map_(),
+ segment_list_(),
+ section_list_(),
+ unattached_section_list_(),
+ sections_are_attached_(false),
+ special_output_list_(),
+ section_headers_(NULL),
+ tls_segment_(NULL),
+ relro_segment_(NULL),
+ symtab_section_(NULL),
+ symtab_xindex_(NULL),
+ dynsym_section_(NULL),
+ dynsym_xindex_(NULL),
+ dynamic_section_(NULL),
+ dynamic_data_(NULL),
+ eh_frame_section_(NULL),
+ eh_frame_data_(NULL),
+ added_eh_frame_data_(false),
+ eh_frame_hdr_section_(NULL),
+ build_id_note_(NULL),
+ debug_abbrev_(NULL),
+ debug_info_(NULL),
+ group_signatures_(),
+ output_file_size_(-1),
input_requires_executable_stack_(false),
input_with_gnu_stack_note_(false),
input_without_gnu_stack_note_(false),
".debug_str",
};
+static const char* lines_only_debug_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)
{
return false;
}
+static inline bool
+is_lines_only_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(lines_only_debug_sections)/sizeof(*lines_only_debug_sections);
+ ++i)
+ if (strcmp(str, lines_only_debug_sections[i]) == 0)
+ return true;
+ return false;
+}
+
// Whether to include this section in the link.
template<int size, bool big_endian>
Layout::include_section(Sized_relobj<size, big_endian>*, const char* name,
const elfcpp::Shdr<size, big_endian>& shdr)
{
+ if (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE)
+ return false;
+
switch (shdr.get_sh_type())
{
case elfcpp::SHT_NULL:
case elfcpp::SHT_SYMTAB:
case elfcpp::SHT_DYNSYM:
- case elfcpp::SHT_STRTAB:
case elfcpp::SHT_HASH:
case elfcpp::SHT_DYNAMIC:
case elfcpp::SHT_SYMTAB_SHNDX:
return false;
+ case elfcpp::SHT_STRTAB:
+ // Discard the sections which have special meanings in the ELF
+ // ABI. Keep others (e.g., .stabstr). We could also do this by
+ // checking the sh_link fields of the appropriate sections.
+ return (strcmp(name, ".dynstr") != 0
+ && strcmp(name, ".strtab") != 0
+ && strcmp(name, ".shstrtab") != 0);
+
case elfcpp::SHT_RELA:
case elfcpp::SHT_REL:
case elfcpp::SHT_GROUP:
case elfcpp::SHT_PROGBITS:
if (parameters->options().strip_debug()
&& (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
+ {
+ if (is_debug_info_section(name))
+ return false;
+ }
+ if (parameters->options().strip_debug_non_line()
+ && (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))
+ && !is_lines_only_debug_section(name))
return false;
}
if (parameters->options().strip_debug_gdb()
&& !is_gdb_debug_section(name))
return false;
}
+ if (parameters->options().strip_lto_sections()
+ && !parameters->options().relocatable()
+ && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
+ {
+ // Ignore LTO sections containing intermediate code.
+ if (is_prefix_of(".gnu.lto_", name))
+ return false;
+ }
return true;
default:
Layout::get_output_section(const char* name, Stringpool::Key name_key,
elfcpp::Elf_Word type, elfcpp::Elf_Xword flags)
{
- const Key key(name_key, std::make_pair(type, flags));
+ elfcpp::Elf_Xword lookup_flags = flags;
+
+ // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine
+ // read-write with read-only sections. Some other ELF linkers do
+ // not do this. FIXME: Perhaps there should be an option
+ // controlling this.
+ lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR);
+
+ const Key key(name_key, std::make_pair(type, lookup_flags));
const std::pair<Key, Output_section*> v(key, NULL);
std::pair<Section_name_map::iterator, bool> ins(
this->section_name_map_.insert(v));
Section_name_map::iterator p =
this->section_name_map_.find(zero_key);
if (p != this->section_name_map_.end())
- {
- os = p->second;
- if ((flags & elfcpp::SHF_ALLOC) != 0)
- this->allocate_output_section(os, flags);
- }
+ os = p->second;
}
}
// 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.
+// linker created section. IS_INPUT_SECTION is true if we are
+// choosing an output section for an input section found in a input
+// file. 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)
+ bool is_input_section)
{
- // We should ignore some flags. FIXME: This will need some
- // adjustment for ld -r.
+ // We should not see any input sections after we have attached
+ // sections to segments.
+ gold_assert(!is_input_section || !this->sections_are_attached_);
+
+ // Some flags in the input section should not be automatically
+ // copied to the output section.
flags &= ~ (elfcpp::SHF_INFO_LINK
| elfcpp::SHF_LINK_ORDER
| elfcpp::SHF_GROUP
if (output_section_slot != NULL)
{
if (*output_section_slot != NULL)
- {
- // If the output section was created unallocated, and we
- // are now allocating it, then we need to clear the
- // address set in the constructor and remove it from the
- // unattached section list.
- if (((*output_section_slot)->flags() & elfcpp::SHF_ALLOC) == 0
- && (flags & elfcpp::SHF_ALLOC) != 0)
- this->allocate_output_section(*output_section_slot, flags);
-
- return *output_section_slot;
- }
+ return *output_section_slot;
// We don't put sections found in the linker script into
// SECTION_NAME_MAP_. That keeps us from getting confused
// output section.
size_t len = strlen(name);
- if (adjust_name && !parameters->options().relocatable())
+ if (is_input_section && !parameters->options().relocatable())
name = Layout::output_section_name(name, &len);
Stringpool::Key name_key;
const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
unsigned int reloc_shndx, unsigned int, off_t* off)
{
+ *off = 0;
+
if (!this->include_section(object, name, shdr))
return NULL;
return NULL;
}
+ // By default the GNU linker sorts input sections whose names match
+ // .ctor.*, .dtor.*, .init_array.*, or .fini_array.*. The sections
+ // are sorted by name. This is used to implement constructor
+ // priority ordering. We are compatible.
+ if (!this->script_options_->saw_sections_clause()
+ && (is_prefix_of(".ctors.", name)
+ || is_prefix_of(".dtors.", name)
+ || is_prefix_of(".init_array.", name)
+ || is_prefix_of(".fini_array.", name)))
+ os->set_must_sort_attached_input_sections();
+
// FIXME: Handle SHF_LINK_ORDER somewhere.
*off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
const char* group_section_name,
const char* signature,
const elfcpp::Shdr<size, big_endian>& shdr,
- const elfcpp::Elf_Word* contents)
+ elfcpp::Elf_Word flags,
+ std::vector<unsigned int>* shndxes)
{
gold_assert(parameters->options().relocatable());
gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP);
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);
+ new Output_data_group<size, big_endian>(object, entry_count, flags,
+ shndxes);
os->add_output_section_data(posd);
}
if (os == NULL)
return NULL;
- // On some targets gcc assumes that a read-only .eh_frame section
- // will be merged with a read-write .eh_frame section.
- if ((shdr.get_sh_flags() & elfcpp::SHF_WRITE) != 0
- && (os->flags() & elfcpp::SHF_WRITE) == 0)
- {
- elfcpp::Elf_Xword new_flags = os->flags() | elfcpp::SHF_WRITE;
- this->write_enable_output_section(os, new_flags);
- os->set_flags(new_flags);
- }
-
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_);
if (this->options_.eh_frame_hdr())
{
shndx,
reloc_shndx,
reloc_type))
- *off = -1;
+ {
+ os->update_flags_for_input_section(shdr.get_sh_flags());
+
+ // We found a .eh_frame section we are going to optimize, so now
+ // we can add the set of optimized sections to the output
+ // section. We need to postpone adding this until we've found a
+ // section we can optimize so that the .eh_frame section in
+ // crtbegin.o winds up at the start of the output section.
+ if (!this->added_eh_frame_data_)
+ {
+ os->add_output_section_data(this->eh_frame_data_);
+ this->added_eh_frame_data_ = true;
+ }
+ *off = -1;
+ }
else
{
// We couldn't handle this .eh_frame section for some reason.
return os;
}
-// Add POSD to an output section using NAME, TYPE, and FLAGS.
+// Add POSD to an output section using NAME, TYPE, and FLAGS. Return
+// the output section.
-void
+Output_section*
Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
elfcpp::Elf_Xword flags,
Output_section_data* posd)
false);
if (os != NULL)
os->add_output_section_data(posd);
+ return os;
}
// Map section flags to segment flags.
&& strcmp(this->options_.compress_debug_sections(), "none") != 0
&& is_compressible_debug_section(name))
os = new Output_compressed_section(&this->options_, name, type, flags);
- else
+
+ else if ((flags & elfcpp::SHF_ALLOC) == 0
+ && this->options_.strip_debug_non_line()
+ && strcmp(".debug_abbrev", name) == 0)
+ {
+ os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section(
+ name, type, flags);
+ if (this->debug_info_)
+ this->debug_info_->set_abbreviations(this->debug_abbrev_);
+ }
+ else if ((flags & elfcpp::SHF_ALLOC) == 0
+ && this->options_.strip_debug_non_line()
+ && strcmp(".debug_info", name) == 0)
+ {
+ os = this->debug_info_ = new Output_reduced_debug_info_section(
+ name, type, flags);
+ if (this->debug_abbrev_)
+ this->debug_info_->set_abbreviations(this->debug_abbrev_);
+ }
+ else
os = new Output_section(name, type, flags);
this->section_list_.push_back(os);
- if ((flags & elfcpp::SHF_ALLOC) == 0)
- this->unattached_section_list_.push_back(os);
- else
- this->attach_to_segment(os, flags);
+ // The GNU linker by default sorts some sections by priority, so we
+ // do the same. We need to know that this might happen before we
+ // attach any input sections.
+ if (!this->script_options_->saw_sections_clause()
+ && (strcmp(name, ".ctors") == 0
+ || strcmp(name, ".dtors") == 0
+ || strcmp(name, ".init_array") == 0
+ || strcmp(name, ".fini_array") == 0))
+ os->set_may_sort_attached_input_sections();
+
+ // With -z relro, we have to recognize the special sections by name.
+ // There is no other way.
+ if (!this->script_options_->saw_sections_clause()
+ && parameters->options().relro()
+ && type == elfcpp::SHT_PROGBITS
+ && (flags & elfcpp::SHF_ALLOC) != 0
+ && (flags & elfcpp::SHF_WRITE) != 0)
+ {
+ if (strcmp(name, ".data.rel.ro") == 0)
+ os->set_is_relro();
+ else if (strcmp(name, ".data.rel.ro.local") == 0)
+ {
+ os->set_is_relro();
+ os->set_is_relro_local();
+ }
+ }
+
+ // If we have already attached the sections to segments, then we
+ // need to attach this one now. This happens for sections created
+ // directly by the linker.
+ if (this->sections_are_attached_)
+ this->attach_section_to_segment(os);
return os;
}
+// Attach output sections to segments. This is called after we have
+// seen all the input sections.
+
+void
+Layout::attach_sections_to_segments()
+{
+ for (Section_list::iterator p = this->section_list_.begin();
+ p != this->section_list_.end();
+ ++p)
+ this->attach_section_to_segment(*p);
+
+ this->sections_are_attached_ = true;
+}
+
+// Attach an output section to a segment.
+
+void
+Layout::attach_section_to_segment(Output_section* os)
+{
+ if ((os->flags() & elfcpp::SHF_ALLOC) == 0)
+ this->unattached_section_list_.push_back(os);
+ else
+ this->attach_allocated_section_to_segment(os);
+}
+
// Attach an allocated output section to a segment.
void
-Layout::attach_to_segment(Output_section* os, elfcpp::Elf_Xword flags)
+Layout::attach_allocated_section_to_segment(Output_section* os)
{
+ elfcpp::Elf_Xword flags = os->flags();
gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
if (parameters->options().relocatable())
++p)
{
if ((*p)->type() == elfcpp::PT_LOAD
- && ((*p)->flags() & elfcpp::PF_W) == (seg_flags & elfcpp::PF_W))
+ && (parameters->options().omagic()
+ || ((*p)->flags() & elfcpp::PF_W) == (seg_flags & elfcpp::PF_W)))
{
// If -Tbss was specified, we need to separate the data
// and BSS segments.
if ((flags & elfcpp::SHF_TLS) != 0)
{
if (this->tls_segment_ == NULL)
- this->tls_segment_ = this->make_output_segment(elfcpp::PT_TLS,
- seg_flags);
+ this->make_output_segment(elfcpp::PT_TLS, seg_flags);
this->tls_segment_->add_output_section(os, seg_flags);
}
+
+ // If -z relro is in effect, and we see a relro section, we create a
+ // PT_GNU_RELRO segment. There can only be one such segment.
+ if (os->is_relro() && parameters->options().relro())
+ {
+ gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W));
+ if (this->relro_segment_ == NULL)
+ this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags);
+ this->relro_segment_->add_output_section(os, seg_flags);
+ }
}
// Make an output section for a script.
return os;
}
-// We have to move an existing output section from the unallocated
-// list to the allocated list.
-
-void
-Layout::allocate_output_section(Output_section* os, elfcpp::Elf_Xword flags)
-{
- os->reset_address_and_file_offset();
-
- Section_list::iterator p = std::find(this->unattached_section_list_.begin(),
- this->unattached_section_list_.end(),
- os);
- gold_assert(p != this->unattached_section_list_.end());
- this->unattached_section_list_.erase(p);
-
- this->attach_to_segment(os, flags);
-}
-
-// We have to move an existing output section from the read-only
-// segment to the writable segment.
-
-void
-Layout::write_enable_output_section(Output_section* os,
- elfcpp::Elf_Xword flags)
-{
- gold_assert((os->flags() & elfcpp::SHF_WRITE) == 0);
- gold_assert(os->type() == elfcpp::SHT_PROGBITS);
- gold_assert((flags & elfcpp::SHF_WRITE) != 0);
- gold_assert((flags & elfcpp::SHF_ALLOC) != 0);
-
- if (parameters->options().relocatable())
- return;
-
- if (this->script_options_->saw_sections_clause())
- return;
-
- Segment_list::iterator p;
- for (p = this->segment_list_.begin();
- p != this->segment_list_.end();
- ++p)
- {
- if ((*p)->type() == elfcpp::PT_LOAD
- && ((*p)->flags() & elfcpp::PF_W) == 0)
- {
- (*p)->remove_output_section(os);
- break;
- }
- }
- gold_assert(p != this->segment_list_.end());
-
- this->attach_to_segment(os, flags);
-}
-
// Return the number of segments we expect to see.
size_t
(elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE),
false);
+ this->dynamic_section_->set_is_relro();
symtab->define_in_output_data("_DYNAMIC", NULL, this->dynamic_section_, 0, 0,
elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
{
if ((*p)->type() == elfcpp::PT_LOAD
&& ((*p)->flags() & elfcpp::PF_R) != 0
- && ((*p)->flags() & elfcpp::PF_W) == 0)
+ && (parameters->options().omagic()
+ || ((*p)->flags() & elfcpp::PF_W) == 0))
return *p;
}
this->create_gold_note();
this->create_executable_stack_info(target);
+ this->create_build_id();
Output_segment* phdr_seg = NULL;
if (!parameters->options().relocatable() && !parameters->doing_static_link())
// sections.
off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
+ // Set the section indexes of all unallocated sections seen so far,
+ // in case any of them are somehow referenced by a symbol.
+ shndx = this->set_section_indexes(shndx);
+
// Create the symbol table sections.
- this->create_symtab_sections(input_objects, symtab, &off);
+ this->create_symtab_sections(input_objects, symtab, shndx, &off);
if (!parameters->doing_static_link())
this->assign_local_dynsym_offsets(input_objects);
// don't have to wait for the input sections.
off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS);
- // Now that all sections have been created, set the section indexes.
+ // Now that all sections have been created, set the section indexes
+ // for any sections which haven't been done yet.
shndx = this->set_section_indexes(shndx);
// Create the section table header.
- this->create_shdrs(&off);
+ this->create_shdrs(shstrtab_section, &off);
// If there are no sections which require postprocessing, we can
// handle the section names now, and avoid a resize later.
return off;
}
-// Create a .note section for an executable or shared library. This
-// records the version of gold used to create the binary.
+// Create a note header following the format defined in the ELF ABI.
+// NAME is the name, NOTE_TYPE is the type, DESCSZ is the size of the
+// descriptor. ALLOCATE is true if the section should be allocated in
+// memory. This returns the new note section. It sets
+// *TRAILING_PADDING to the number of trailing zero bytes required.
-void
-Layout::create_gold_note()
+Output_section*
+Layout::create_note(const char* name, int note_type, size_t descsz,
+ bool allocate, size_t* trailing_padding)
{
- 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.
#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;
+ size_t notehdrsz = 3 * (size / 8) + aligned_namesz;
- unsigned char buffer[128];
- gold_assert(sizeof buffer >= notesz);
- memset(buffer, 0, notesz);
+ unsigned char* buffer = new unsigned char[notehdrsz];
+ memset(buffer, 0, notehdrsz);
bool is_big_endian = parameters->target().is_big_endian();
gold_unreachable();
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);
+ elfcpp::Elf_Xword flags = 0;
+ if (allocate)
+ flags = elfcpp::SHF_ALLOC;
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);
+ flags);
+ Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz,
+ size / 8,
+ "** note header");
+ os->add_output_section_data(posd);
+
+ *trailing_padding = aligned_descsz - descsz;
+
+ return os;
+}
+
+// For an executable or shared library, create a note to record the
+// version of gold used to create the binary.
+
+void
+Layout::create_gold_note()
+{
+ if (parameters->options().relocatable())
+ return;
+
+ std::string desc = std::string("gold ") + gold::get_version_string();
+
+ size_t trailing_padding;
+ Output_section *os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION,
+ desc.size(), false, &trailing_padding);
+
+ Output_section_data* posd = new Output_data_const(desc, 4);
os->add_output_section_data(posd);
+
+ if (trailing_padding > 0)
+ {
+ posd = new Output_data_zero_fill(trailing_padding, 0);
+ os->add_output_section_data(posd);
+ }
}
// Record whether the stack should be executable. This can be set
}
}
+// If --build-id was used, set up the build ID note.
+
+void
+Layout::create_build_id()
+{
+ if (!parameters->options().user_set_build_id())
+ return;
+
+ const char* style = parameters->options().build_id();
+ if (strcmp(style, "none") == 0)
+ return;
+
+ // Set DESCSZ to the size of the note descriptor. When possible,
+ // set DESC to the note descriptor contents.
+ size_t descsz;
+ std::string desc;
+ if (strcmp(style, "md5") == 0)
+ descsz = 128 / 8;
+ else if (strcmp(style, "sha1") == 0)
+ descsz = 160 / 8;
+ else if (strcmp(style, "uuid") == 0)
+ {
+ const size_t uuidsz = 128 / 8;
+
+ char buffer[uuidsz];
+ memset(buffer, 0, uuidsz);
+
+ int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY);
+ if (descriptor < 0)
+ gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"),
+ strerror(errno));
+ else
+ {
+ ssize_t got = ::read(descriptor, buffer, uuidsz);
+ release_descriptor(descriptor, true);
+ if (got < 0)
+ gold_error(_("/dev/urandom: read failed: %s"), strerror(errno));
+ else if (static_cast<size_t>(got) != uuidsz)
+ gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"),
+ uuidsz, got);
+ }
+
+ desc.assign(buffer, uuidsz);
+ descsz = uuidsz;
+ }
+ else if (strncmp(style, "0x", 2) == 0)
+ {
+ hex_init();
+ const char* p = style + 2;
+ while (*p != '\0')
+ {
+ if (hex_p(p[0]) && hex_p(p[1]))
+ {
+ char c = (hex_value(p[0]) << 4) | hex_value(p[1]);
+ desc += c;
+ p += 2;
+ }
+ else if (*p == '-' || *p == ':')
+ ++p;
+ else
+ gold_fatal(_("--build-id argument '%s' not a valid hex number"),
+ style);
+ }
+ descsz = desc.size();
+ }
+ else
+ gold_fatal(_("unrecognized --build-id argument '%s'"), style);
+
+ // Create the note.
+ size_t trailing_padding;
+ Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID,
+ descsz, true, &trailing_padding);
+
+ if (!desc.empty())
+ {
+ // We know the value already, so we fill it in now.
+ gold_assert(desc.size() == descsz);
+
+ Output_section_data* posd = new Output_data_const(desc, 4);
+ os->add_output_section_data(posd);
+
+ if (trailing_padding != 0)
+ {
+ posd = new Output_data_zero_fill(trailing_padding, 0);
+ os->add_output_section_data(posd);
+ }
+ }
+ else
+ {
+ // We need to compute a checksum after we have completed the
+ // link.
+ gold_assert(trailing_padding == 0);
+ this->build_id_note_ = new Output_data_zero_fill(descsz, 4);
+ os->add_output_section_data(this->build_id_note_);
+ os->set_after_input_sections();
+ }
+}
+
// 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.
if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD)
return false;
- // We put the PT_TLS segment last, because that is where the dynamic
- // linker expects to find it (this is just for efficiency; other
- // positions would also work correctly).
- if (type1 == elfcpp::PT_TLS && type2 != elfcpp::PT_TLS)
+ // We put the PT_TLS segment last except for the PT_GNU_RELRO
+ // segment, because that is where the dynamic linker expects to find
+ // it (this is just for efficiency; other positions would also work
+ // correctly).
+ if (type1 == elfcpp::PT_TLS
+ && type2 != elfcpp::PT_TLS
+ && type2 != elfcpp::PT_GNU_RELRO)
return false;
- if (type2 == elfcpp::PT_TLS && type1 != elfcpp::PT_TLS)
+ if (type2 == elfcpp::PT_TLS
+ && type1 != elfcpp::PT_TLS
+ && type1 != elfcpp::PT_GNU_RELRO)
+ return true;
+
+ // We put the PT_GNU_RELRO segment last, because that is where the
+ // dynamic linker expects to find it (as with PT_TLS, this is just
+ // for efficiency).
+ if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO)
+ return false;
+ if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO)
return true;
const elfcpp::Elf_Word flags1 = seg1->flags();
}
}
+ const bool check_sections = parameters->options().check_sections();
+ Output_segment* last_load_segment = NULL;
+
bool was_readonly = false;
for (Segment_list::iterator p = this->segment_list_.begin();
p != this->segment_list_.end();
uint64_t aligned_addr = 0;
uint64_t abi_pagesize = target->abi_pagesize();
+ uint64_t common_pagesize = target->common_pagesize();
- // FIXME: This should depend on the -n and -N options.
- (*p)->set_minimum_p_align(target->common_pagesize());
+ if (!parameters->options().nmagic()
+ && !parameters->options().omagic())
+ (*p)->set_minimum_p_align(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;
+ if (!parameters->options().nmagic()
+ && !parameters->options().omagic())
+ {
+ // 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
{
}
unsigned int shndx_hold = *pshndx;
- uint64_t new_addr = (*p)->set_section_addresses(false, addr, &off,
- pshndx);
+ uint64_t new_addr = (*p)->set_section_addresses(this, 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
if (!are_addresses_set && aligned_addr != addr)
{
- uint64_t common_pagesize = target->common_pagesize();
uint64_t first_off = (common_pagesize
- (aligned_addr
& (common_pagesize - 1)));
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(true, addr, &off,
- pshndx);
+ new_addr = (*p)->set_section_addresses(this, true, addr,
+ &off, pshndx);
}
}
if (((*p)->flags() & elfcpp::PF_W) == 0)
was_readonly = true;
+
+ // Implement --check-sections. We know that the segments
+ // are sorted by LMA.
+ if (check_sections && last_load_segment != NULL)
+ {
+ gold_assert(last_load_segment->paddr() <= (*p)->paddr());
+ if (last_load_segment->paddr() + last_load_segment->memsz()
+ > (*p)->paddr())
+ {
+ unsigned long long lb1 = last_load_segment->paddr();
+ unsigned long long le1 = lb1 + last_load_segment->memsz();
+ unsigned long long lb2 = (*p)->paddr();
+ unsigned long long le2 = lb2 + (*p)->memsz();
+ gold_error(_("load segment overlap [0x%llx -> 0x%llx] and "
+ "[0x%llx -> 0x%llx]"),
+ lb1, le1, lb2, le2);
+ }
+ }
+ last_load_segment = *p;
}
}
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;
+ if (!(*p)->has_out_shndx())
+ {
+ (*p)->set_out_shndx(shndx);
+ ++shndx;
+ }
}
return shndx;
}
// 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.
+// fully laid out. SHNUM is the number of sections so far.
void
Layout::create_symtab_sections(const Input_objects* input_objects,
Symbol_table* symtab,
+ unsigned int shnum,
off_t* poff)
{
int symsize;
this->symtab_section_ = osymtab;
Output_section_data* pos = new Output_data_fixed_space(off - startoff,
- align);
+ align,
+ "** symtab");
osymtab->add_output_section_data(pos);
+ // We generate a .symtab_shndx section if we have more than
+ // SHN_LORESERVE sections. Technically it is possible that we
+ // don't need one, because it is possible that there are no
+ // symbols in any of sections with indexes larger than
+ // SHN_LORESERVE. That is probably unusual, though, and it is
+ // easier to always create one than to compute section indexes
+ // twice (once here, once when writing out the symbols).
+ if (shnum >= elfcpp::SHN_LORESERVE)
+ {
+ const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx",
+ false, NULL);
+ Output_section* osymtab_xindex =
+ this->make_output_section(symtab_xindex_name,
+ elfcpp::SHT_SYMTAB_SHNDX, 0);
+
+ size_t symcount = (off - startoff) / symsize;
+ this->symtab_xindex_ = new Output_symtab_xindex(symcount);
+
+ osymtab_xindex->add_output_section_data(this->symtab_xindex_);
+
+ osymtab_xindex->set_link_section(osymtab);
+ osymtab_xindex->set_addralign(4);
+ osymtab_xindex->set_entsize(4);
+
+ osymtab_xindex->set_after_input_sections();
+
+ // This tells the driver code to wait until the symbol table
+ // has written out before writing out the postprocessing
+ // sections, including the .symtab_shndx section.
+ this->any_postprocessing_sections_ = true;
+ }
+
const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
Output_section* ostrtab = this->make_output_section(strtab_name,
elfcpp::SHT_STRTAB,
// offset.
void
-Layout::create_shdrs(off_t* poff)
+Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff)
{
Output_section_headers* oshdrs;
oshdrs = new Output_section_headers(this,
&this->segment_list_,
&this->section_list_,
&this->unattached_section_list_,
- &this->namepool_);
+ &this->namepool_,
+ shstrtab_section);
off_t off = align_address(*poff, oshdrs->addralign());
oshdrs->set_address_and_file_offset(0, off);
off += oshdrs->data_size();
this->section_headers_ = oshdrs;
}
+// Count the allocated sections.
+
+size_t
+Layout::allocated_output_section_count() const
+{
+ size_t section_count = 0;
+ for (Segment_list::const_iterator p = this->segment_list_.begin();
+ p != this->segment_list_.end();
+ ++p)
+ section_count += (*p)->output_section_count();
+ return section_count;
+}
+
// Create the dynamic symbol table.
void
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);
false);
Output_section_data* odata = new Output_data_fixed_space(index * symsize,
- align);
+ align,
+ "** dynsym");
dynsym->add_output_section_data(odata);
dynsym->set_info(local_symcount);
odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym);
odyn->add_constant(elfcpp::DT_SYMENT, symsize);
+ // If there are more than SHN_LORESERVE allocated sections, we
+ // create a .dynsym_shndx section. It is possible that we don't
+ // need one, because it is possible that there are no dynamic
+ // symbols in any of the sections with indexes larger than
+ // SHN_LORESERVE. This is probably unusual, though, and at this
+ // time we don't know the actual section indexes so it is
+ // inconvenient to check.
+ if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE)
+ {
+ Output_section* dynsym_xindex =
+ this->choose_output_section(NULL, ".dynsym_shndx",
+ elfcpp::SHT_SYMTAB_SHNDX,
+ elfcpp::SHF_ALLOC,
+ false);
+
+ this->dynsym_xindex_ = new Output_symtab_xindex(index);
+
+ dynsym_xindex->add_output_section_data(this->dynsym_xindex_);
+
+ dynsym_xindex->set_link_section(dynsym);
+ dynsym_xindex->set_addralign(4);
+ dynsym_xindex->set_entsize(4);
+
+ dynsym_xindex->set_after_input_sections();
+
+ // This tells the driver code to wait until the symbol table has
+ // written out before writing out the postprocessing sections,
+ // including the .dynsym_shndx section.
+ this->any_postprocessing_sections_ = true;
+ }
+
// Create the dynamic string table section.
Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
Output_section_data* hashdata = new Output_data_const_buffer(phash,
hashlen,
- align);
+ align,
+ "** hash");
hashsec->add_output_section_data(hashdata);
hashsec->set_link_section(dynsym);
Output_section_data* hashdata = new Output_data_const_buffer(phash,
hashlen,
- align);
+ align,
+ "** hash");
hashsec->add_output_section_data(hashdata);
hashsec->set_link_section(dynsym);
dynamic_symbols,
&vbuf, &vsize);
- Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2);
+ Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2,
+ "** versions");
vsec->add_output_section_data(vdata);
vsec->set_entsize(2);
versions->def_section_contents<size, big_endian>(&this->dynpool_, &vdbuf,
&vdsize, &vdentries);
- Output_section_data* vddata = new Output_data_const_buffer(vdbuf,
- vdsize,
- 4);
+ Output_section_data* vddata =
+ new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs");
vdsec->add_output_section_data(vddata);
vdsec->set_link_section(dynstr);
&vnbuf, &vnsize,
&vnentries);
- Output_section_data* vndata = new Output_data_const_buffer(vnbuf,
- vnsize,
- 4);
+ Output_section_data* vndata =
+ new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs");
vnsec->add_output_section_data(vndata);
vnsec->set_link_section(dynstr);
{
Output_segment* oseg = this->make_output_segment(elfcpp::PT_INTERP,
elfcpp::PF_R);
- oseg->add_initial_output_section(osec, elfcpp::PF_R);
+ oseg->add_output_section(osec, elfcpp::PF_R);
}
}
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);
+ oseg->add_output_section(this->dynamic_section_,
+ elfcpp::PF_R | elfcpp::PF_W);
}
Output_data_dynamic* const odyn = this->dynamic_data_;
}
odyn->add_string(elfcpp::DT_RPATH, rpath_val);
+ if (parameters->options().enable_new_dtags())
+ odyn->add_string(elfcpp::DT_RUNPATH, rpath_val);
}
// Look for text segments that have dynamic relocations.
}
if (parameters->options().shared() && this->has_static_tls())
flags |= elfcpp::DF_STATIC_TLS;
+ if (parameters->options().origin())
+ flags |= elfcpp::DF_ORIGIN;
odyn->add_constant(elfcpp::DT_FLAGS, flags);
+
+ flags = 0;
+ if (parameters->options().initfirst())
+ flags |= elfcpp::DF_1_INITFIRST;
+ if (parameters->options().interpose())
+ flags |= elfcpp::DF_1_INTERPOSE;
+ if (parameters->options().loadfltr())
+ flags |= elfcpp::DF_1_LOADFLTR;
+ if (parameters->options().nodefaultlib())
+ flags |= elfcpp::DF_1_NODEFLIB;
+ if (parameters->options().nodelete())
+ flags |= elfcpp::DF_1_NODELETE;
+ if (parameters->options().nodlopen())
+ flags |= elfcpp::DF_1_NOOPEN;
+ if (parameters->options().nodump())
+ flags |= elfcpp::DF_1_NODUMP;
+ if (!parameters->options().shared())
+ flags &= ~(elfcpp::DF_1_INITFIRST
+ | elfcpp::DF_1_NODELETE
+ | elfcpp::DF_1_NOOPEN);
+ if (parameters->options().origin())
+ flags |= elfcpp::DF_1_ORIGIN;
+ if (flags)
+ odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
}
// The mapping of .gnu.linkonce section names to real section names.
#define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 }
const Layout::Linkonce_mapping Layout::linkonce_mapping[] =
{
- MAPPING_INIT("d.rel.ro", ".data.rel.ro"), // Must be before "d".
+ MAPPING_INIT("d.rel.ro.local", ".data.rel.ro.local"), // Before "d.rel.ro".
+ MAPPING_INIT("d.rel.ro", ".data.rel.ro"), // Before "d".
MAPPING_INIT("t", ".text"),
MAPPING_INIT("r", ".rodata"),
MAPPING_INIT("d", ".data"),
// initial '.', we use the name unchanged (i.e., "mysection" and
// ".text" are unchanged).
+ // If the name starts with ".data.rel.ro.local" we use
+ // ".data.rel.ro.local".
+
// If the name starts with ".data.rel.ro" we use ".data.rel.ro".
// Otherwise, we drop the second '.' and everything that comes after
if (sdot == NULL)
return name;
+ const char* const data_rel_ro_local = ".data.rel.ro.local";
+ if (strncmp(name, data_rel_ro_local, strlen(data_rel_ro_local)) == 0)
+ {
+ *plen = strlen(data_rel_ro_local);
+ return data_rel_ro_local;
+ }
+
const char* const data_rel_ro = ".data.rel.ro";
if (strncmp(name, data_rel_ro, strlen(data_rel_ro)) == 0)
{
// want a linkonce signature to block another linkonce signature.
bool
-Layout::add_comdat(const char* signature, bool group)
+Layout::add_comdat(Relobj* object, unsigned int shndx,
+ const std::string& signature, bool group)
{
- std::string sig(signature);
+ Kept_section kept(object, shndx, group);
std::pair<Signatures::iterator, bool> ins(
- this->signatures_.insert(std::make_pair(sig, group)));
+ this->signatures_.insert(std::make_pair(signature, kept)));
if (ins.second)
{
return true;
}
- if (ins.first->second)
+ if (ins.first->second.group_)
{
// We've already seen a real section group with this signature.
+ // If the kept group is from a plugin object, and we're in
+ // the replacement phase, accept the new one as a replacement.
+ if (ins.first->second.object_ == NULL
+ && parameters->options().plugins()->in_replacement_phase())
+ {
+ ins.first->second = kept;
+ return true;
+ }
return false;
}
else if (group)
// This is a real section group, and we've already seen a
// linkonce section with this signature. Record that we've seen
// a section group, and don't include this section group.
- ins.first->second = true;
+ ins.first->second.group_ = true;
return false;
}
else
}
}
+// Find the given comdat signature, and return the object and section
+// index of the kept group.
+Relobj*
+Layout::find_kept_object(const std::string& signature,
+ unsigned int* pshndx) const
+{
+ Signatures::const_iterator p = this->signatures_.find(signature);
+ if (p == this->signatures_.end())
+ return NULL;
+ if (pshndx != NULL)
+ *pshndx = p->second.shndx_;
+ return p->second.object_;
+}
+
// Store the allocated sections into the section list.
void
gold_assert(!parameters->options().relocatable());
Output_segment* oseg = new Output_segment(type, flags);
this->segment_list_.push_back(oseg);
+
+ if (type == elfcpp::PT_TLS)
+ this->tls_segment_ = oseg;
+ else if (type == elfcpp::PT_GNU_RELRO)
+ this->relro_segment_ = oseg;
+
return oseg;
}
gold_assert(index > 0 && index != -1U);
off_t off = (symtab_section->offset()
+ index * symtab_section->entsize());
- symtab->write_section_symbol(*p, of, off);
+ symtab->write_section_symbol(*p, this->symtab_xindex_, of, off);
}
}
}
gold_assert(index > 0 && index != -1U);
off_t off = (dynsym_section->offset()
+ index * dynsym_section->entsize());
- symtab->write_section_symbol(*p, of, off);
+ symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off);
}
}
this->section_headers_->write(of);
}
+// If the build ID requires computing a checksum, do so here, and
+// write it out. We compute a checksum over the entire file because
+// that is simplest.
+
+void
+Layout::write_build_id(Output_file* of) const
+{
+ if (this->build_id_note_ == NULL)
+ return;
+
+ const unsigned char* iv = of->get_input_view(0, this->output_file_size_);
+
+ unsigned char* ov = of->get_output_view(this->build_id_note_->offset(),
+ this->build_id_note_->data_size());
+
+ const char* style = parameters->options().build_id();
+ if (strcmp(style, "sha1") == 0)
+ {
+ sha1_ctx ctx;
+ sha1_init_ctx(&ctx);
+ sha1_process_bytes(iv, this->output_file_size_, &ctx);
+ sha1_finish_ctx(&ctx, ov);
+ }
+ else if (strcmp(style, "md5") == 0)
+ {
+ md5_ctx ctx;
+ md5_init_ctx(&ctx);
+ md5_process_bytes(iv, this->output_file_size_, &ctx);
+ md5_finish_ctx(&ctx, ov);
+ }
+ else
+ gold_unreachable();
+
+ of->write_output_view(this->build_id_note_->offset(),
+ this->build_id_note_->data_size(),
+ ov);
+
+ of->free_input_view(0, this->output_file_size_, iv);
+}
+
// 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
out.close();
}
+// Print the output sections to the map file.
+
+void
+Layout::print_to_mapfile(Mapfile* mapfile) const
+{
+ for (Segment_list::const_iterator p = this->segment_list_.begin();
+ p != this->segment_list_.end();
+ ++p)
+ (*p)->print_sections_to_mapfile(mapfile);
+}
+
// Print statistical information to stderr. This is used for --stats.
void
Write_symbols_task::run(Workqueue*)
{
this->symtab_->write_globals(this->input_objects_, this->sympool_,
- this->dynpool_, this->of_);
+ this->dynpool_, this->layout_->symtab_xindex(),
+ this->layout_->dynsym_xindex(), this->of_);
}
// Write_after_input_sections_task methods.
void
Close_task_runner::run(Workqueue*, const Task*)
{
+ // If we need to compute a checksum for the BUILD if, we do so here.
+ this->layout_->write_build_id(this->of_);
+
// 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_);
const char* group_section_name,
const char* signature,
const elfcpp::Shdr<32, false>& shdr,
- const elfcpp::Elf_Word* contents);
+ elfcpp::Elf_Word flags,
+ std::vector<unsigned int>* shndxes);
#endif
#ifdef HAVE_TARGET_32_BIG
const char* group_section_name,
const char* signature,
const elfcpp::Shdr<32, true>& shdr,
- const elfcpp::Elf_Word* contents);
+ elfcpp::Elf_Word flags,
+ std::vector<unsigned int>* shndxes);
#endif
#ifdef HAVE_TARGET_64_LITTLE
const char* group_section_name,
const char* signature,
const elfcpp::Shdr<64, false>& shdr,
- const elfcpp::Elf_Word* contents);
+ elfcpp::Elf_Word flags,
+ std::vector<unsigned int>* shndxes);
#endif
#ifdef HAVE_TARGET_64_BIG
const char* group_section_name,
const char* signature,
const elfcpp::Shdr<64, true>& shdr,
- const elfcpp::Elf_Word* contents);
+ elfcpp::Elf_Word flags,
+ std::vector<unsigned int>* shndxes);
#endif
#ifdef HAVE_TARGET_32_LITTLE