// layout.cc -- lay out output file sections for gold
-// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
section_headers_(NULL),
tls_segment_(NULL),
relro_segment_(NULL),
+ increase_relro_(0),
symtab_section_(NULL),
symtab_xindex_(NULL),
dynsym_section_(NULL),
dynsym_xindex_(NULL),
dynamic_section_(NULL),
+ dynamic_symbol_(NULL),
dynamic_data_(NULL),
eh_frame_section_(NULL),
eh_frame_data_(NULL),
debug_info_(NULL),
group_signatures_(),
output_file_size_(-1),
+ have_added_input_section_(false),
sections_are_attached_(false),
input_requires_executable_stack_(false),
input_with_gnu_stack_note_(false),
if (is_prefix_of(".gnu.lto_", name))
return false;
}
+ // The GNU linker strips .gnu_debuglink sections, so we do too.
+ // This is a feature used to keep debugging information in
+ // separate files.
+ if (strcmp(name, ".gnu_debuglink") == 0)
+ return false;
return true;
default:
// and section flags FLAGS. NAME must be canonicalized in the string
// pool, and NAME_KEY is the key. IS_INTERP is true if this is the
// .interp section. IS_DYNAMIC_LINKER_SECTION is true if this section
-// is used by the dynamic linker.
+// is used by the dynamic linker. IS_RELRO is true for a relro
+// section. IS_LAST_RELRO is true for the last relro section.
+// IS_FIRST_NON_RELRO is true for the first non-relro section.
Output_section*
Layout::get_output_section(const char* name, Stringpool::Key name_key,
elfcpp::Elf_Word type, elfcpp::Elf_Xword flags,
- bool is_interp, bool is_dynamic_linker_section)
+ bool is_interp, bool is_dynamic_linker_section,
+ bool is_relro, bool is_last_relro,
+ bool is_first_non_relro)
{
elfcpp::Elf_Xword lookup_flags = flags;
if (os == NULL)
os = this->make_output_section(name, type, flags, is_interp,
- is_dynamic_linker_section);
+ is_dynamic_linker_section, is_relro,
+ is_last_relro, is_first_non_relro);
ins.first->second = os;
return os;
}
// choosing an output section for an input section found in a input
// file. IS_INTERP is true if this is the .interp section.
// IS_DYNAMIC_LINKER_SECTION is true if this section is used by the
-// dynamic linker. This will return NULL if the input section should
-// be discarded.
+// dynamic linker. IS_RELRO is true for a relro section.
+// IS_LAST_RELRO is true for the last relro section.
+// IS_FIRST_NON_RELRO is true for the first non-relro section. 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 is_input_section, bool is_interp,
- bool is_dynamic_linker_section)
+ bool is_dynamic_linker_section, bool is_relro,
+ bool is_last_relro, bool is_first_non_relro)
{
// We should not see any input sections after we have attached
// sections to segments.
Output_section* os =
this->make_output_section(name, type, flags, is_interp,
- is_dynamic_linker_section);
+ is_dynamic_linker_section, is_relro,
+ is_last_relro, is_first_non_relro);
os->set_found_in_sections_clause();
*output_section_slot = os;
return os;
// 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, is_interp,
- is_dynamic_linker_section);
+ is_dynamic_linker_section, is_relro,
+ is_last_relro, is_first_non_relro);
}
// Return the output section to use for input section SHNDX, with name
{
name = this->namepool_.add(name, true, NULL);
os = this->make_output_section(name, shdr.get_sh_type(),
- shdr.get_sh_flags(), false, false);
+ shdr.get_sh_flags(), false, false,
+ false, false, false);
}
else
{
os = this->choose_output_section(object, name, shdr.get_sh_type(),
shdr.get_sh_flags(), true, false,
- false);
+ false, false, false, false);
if (os == NULL)
return NULL;
}
*off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
this->script_options_->saw_sections_clause());
+ this->have_added_input_section_ = true;
return os;
}
Output_section* os = this->choose_output_section(object, name.c_str(),
sh_type,
shdr.get_sh_flags(),
+ false, false, false,
false, false, false);
os->set_should_link_to_symtab();
Output_section* os = this->make_output_section(group_section_name,
elfcpp::SHT_GROUP,
shdr.get_sh_flags(),
+ false, false, false,
false, false);
// We need to find a symbol with the signature in the symbol table.
name,
elfcpp::SHT_PROGBITS,
elfcpp::SHF_ALLOC,
+ false, false, false,
false, false, false);
if (os == NULL)
return NULL;
".eh_frame_hdr",
elfcpp::SHT_PROGBITS,
elfcpp::SHF_ALLOC,
+ false, false, false,
false, false, false);
if (hdr_os != NULL)
bool saw_sections_clause = this->script_options_->saw_sections_clause();
*off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
saw_sections_clause);
+ this->have_added_input_section_ = true;
}
return os;
Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type,
elfcpp::Elf_Xword flags,
Output_section_data* posd,
- bool is_dynamic_linker_section)
+ bool is_dynamic_linker_section,
+ bool is_relro, bool is_last_relro,
+ bool is_first_non_relro)
{
Output_section* os = this->choose_output_section(NULL, name, type, flags,
false, false,
- is_dynamic_linker_section);
+ is_dynamic_linker_section,
+ is_relro, is_last_relro,
+ is_first_non_relro);
if (os != NULL)
os->add_output_section_data(posd);
return os;
// Make a new Output_section, and attach it to segments as
// appropriate. IS_INTERP is true if this is the .interp section.
// IS_DYNAMIC_LINKER_SECTION is true if this section is used by the
-// dynamic linker.
+// dynamic linker. IS_RELRO is true if this is a relro section.
+// IS_LAST_RELRO is true if this is the last relro section.
+// IS_FIRST_NON_RELRO is true if this is the first non relro section.
Output_section*
Layout::make_output_section(const char* name, elfcpp::Elf_Word type,
elfcpp::Elf_Xword flags, bool is_interp,
- bool is_dynamic_linker_section)
+ bool is_dynamic_linker_section, bool is_relro,
+ bool is_last_relro, bool is_first_non_relro)
{
Output_section* os;
if ((flags & elfcpp::SHF_ALLOC) == 0
os->set_is_interp();
if (is_dynamic_linker_section)
os->set_is_dynamic_linker_section();
+ if (is_relro)
+ os->set_is_relro();
+ if (is_last_relro)
+ os->set_is_last_relro();
+ if (is_first_non_relro)
+ os->set_is_first_non_relro();
parameters->target().new_output_section(os);
elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags);
- bool sort_sections = !this->script_options_->saw_sections_clause();
+ // Check for --section-start.
+ uint64_t addr;
+ bool is_address_set = parameters->options().section_start(os->name(), &addr);
// 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
if (os->is_large_data_section() && !(*p)->is_large_data_segment())
continue;
- (*p)->add_output_section(os, seg_flags, sort_sections);
+ if (is_address_set)
+ {
+ if ((*p)->are_addresses_set())
+ continue;
+
+ (*p)->add_initial_output_data(os);
+ (*p)->update_flags_for_output_section(seg_flags);
+ (*p)->set_addresses(addr, addr);
+ break;
+ }
+
+ (*p)->add_output_section(os, seg_flags, true);
break;
}
seg_flags);
if (os->is_large_data_section())
oseg->set_is_large_data_segment();
- oseg->add_output_section(os, seg_flags, sort_sections);
+ oseg->add_output_section(os, seg_flags, true);
+ if (is_address_set)
+ oseg->set_addresses(addr, addr);
}
// If we see a loadable SHT_NOTE section, we create a PT_NOTE
name = this->namepool_.add(name, false, NULL);
Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS,
elfcpp::SHF_ALLOC, false,
- false);
+ false, false, false, false);
os->set_found_in_sections_clause();
return os;
}
elfcpp::SHT_DYNAMIC,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE),
- false, false, true);
- this->dynamic_section_->set_is_relro();
+ false, false, true,
+ true, false, 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_symbol_ =
+ symtab->define_in_output_data("_DYNAMIC", NULL, Symbol_table::PREDEFINED,
+ 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_);
++p)
{
const char* const name = (*p)->name();
- if (name[strspn(name,
- ("0123456789"
- "ABCDEFGHIJKLMNOPWRSTUVWXYZ"
- "abcdefghijklmnopqrstuvwxyz"
- "_"))]
- == '\0')
+ if (is_cident(name))
{
const std::string name_string(name);
- const std::string start_name("__start_" + name_string);
- const std::string stop_name("__stop_" + name_string);
+ const std::string start_name(cident_section_start_prefix
+ + name_string);
+ const std::string stop_name(cident_section_stop_prefix
+ + name_string);
symtab->define_in_output_data(start_name.c_str(),
NULL, // version
+ Symbol_table::PREDEFINED,
*p,
0, // value
0, // symsize
symtab->define_in_output_data(stop_name.c_str(),
NULL, // version
+ Symbol_table::PREDEFINED,
*p,
0, // value
0, // symsize
!= General_options::OBJECT_FORMAT_ELF)
load_seg = NULL;
+ // If the user set the address of the text segment, that may not be
+ // compatible with putting the segment headers and file headers into
+ // that segment.
+ if (parameters->options().user_set_Ttext())
+ load_seg = NULL;
+
gold_assert(phdr_seg == NULL
|| load_seg != NULL
|| this->script_options_->saw_sections_clause());
+ // If the address of the load segment we found has been set by
+ // --section-start rather than by a script, then we don't want to
+ // use it for the file and segment headers.
+ if (load_seg != NULL
+ && load_seg->are_addresses_set()
+ && !this->script_options_->saw_sections_clause())
+ load_seg = NULL;
+
// Lay out the segment headers.
if (!parameters->options().relocatable())
{
// dynamic string table is complete.
this->create_version_sections(&versions, symtab, local_dynamic_count,
dynamic_symbols, dynstr);
+
+ // Set the size of the _DYNAMIC symbol. We can't do this until
+ // after we call create_version_sections.
+ this->set_dynamic_symbol_size(symtab);
}
if (this->incremental_inputs_)
Output_section* os = this->choose_output_section(NULL, section_name,
elfcpp::SHT_NOTE,
flags, false, false,
- false);
+ false, false, false, false);
if (os == NULL)
return NULL;
if (is_stack_executable)
flags |= elfcpp::SHF_EXECINSTR;
this->make_output_section(name, elfcpp::SHT_PROGBITS, flags, false,
- false);
+ false, false, false, false);
}
else
{
Output_section* inputs_os =
this->make_output_section(incremental_inputs_name,
elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0,
- false, false);
+ false, false, false, false, false);
Output_section_data* posd =
this->incremental_inputs_->create_incremental_inputs_section_data();
inputs_os->add_output_section_data(posd);
this->namepool_.add(".gnu_incremental_strtab", false, NULL);
Output_section* strtab_os = this->make_output_section(incremental_strtab_name,
elfcpp::SHT_STRTAB,
- 0, false, false);
+ 0, false, false,
+ false, false, false);
Output_data_strtab* strtab_data =
new Output_data_strtab(this->incremental_inputs_->get_stringpool());
strtab_os->add_output_section_data(strtab_data);
}
}
+ unsigned int increase_relro = this->increase_relro_;
+ if (this->script_options_->saw_sections_clause())
+ increase_relro = 0;
+
const bool check_sections = parameters->options().check_sections();
Output_segment* last_load_segment = NULL;
unsigned int shndx_hold = *pshndx;
uint64_t new_addr = (*p)->set_section_addresses(this, false, addr,
+ increase_relro,
&off, pshndx);
// Now that we know the size of this segment, we may be able
off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
off = align_file_offset(off, addr, abi_pagesize);
new_addr = (*p)->set_section_addresses(this, true, addr,
+ increase_relro,
&off, pshndx);
}
}
++p)
{
if ((*p)->type() != elfcpp::PT_LOAD)
- (*p)->set_offset();
+ (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO
+ ? increase_relro
+ : 0);
}
// Set the TLS offsets for each section in the PT_TLS segment.
const char* symtab_name = this->namepool_.add(".symtab", false, NULL);
Output_section* osymtab = this->make_output_section(symtab_name,
elfcpp::SHT_SYMTAB,
- 0, false, false);
+ 0, false, false,
+ false, false, false);
this->symtab_section_ = osymtab;
Output_section_data* pos = new Output_data_fixed_space(off - startoff,
Output_section* osymtab_xindex =
this->make_output_section(symtab_xindex_name,
elfcpp::SHT_SYMTAB_SHNDX, 0, false,
- false);
+ false, false, false, false);
size_t symcount = (off - startoff) / symsize;
this->symtab_xindex_ = new Output_symtab_xindex(symcount);
const char* strtab_name = this->namepool_.add(".strtab", false, NULL);
Output_section* ostrtab = this->make_output_section(strtab_name,
elfcpp::SHT_STRTAB,
- 0, false, false);
+ 0, false, false,
+ false, false, false);
Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
ostrtab->add_output_section_data(pstr);
const char* name = this->namepool_.add(".shstrtab", false, NULL);
Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0,
- false, false);
+ false, false, false, false,
+ false);
if (strcmp(parameters->options().compress_debug_sections(), "none") != 0)
{
Output_section* dynsym = this->choose_output_section(NULL, ".dynsym",
elfcpp::SHT_DYNSYM,
elfcpp::SHF_ALLOC,
- false, false, true);
+ false, false, true,
+ false, false, false);
Output_section_data* odata = new Output_data_fixed_space(index * symsize,
align,
this->choose_output_section(NULL, ".dynsym_shndx",
elfcpp::SHT_SYMTAB_SHNDX,
elfcpp::SHF_ALLOC,
- false, false, true);
+ false, false, true, false, false, false);
this->dynsym_xindex_ = new Output_symtab_xindex(index);
Output_section* dynstr = this->choose_output_section(NULL, ".dynstr",
elfcpp::SHT_STRTAB,
elfcpp::SHF_ALLOC,
- false, false, true);
+ false, false, true,
+ false, false, false);
Output_section_data* strdata = new Output_data_strtab(&this->dynpool_);
dynstr->add_output_section_data(strdata);
Output_section* hashsec = this->choose_output_section(NULL, ".hash",
elfcpp::SHT_HASH,
elfcpp::SHF_ALLOC,
- false, false, true);
+ false, false, true,
+ false, false,
+ false);
Output_section_data* hashdata = new Output_data_const_buffer(phash,
hashlen,
Output_section* hashsec = this->choose_output_section(NULL, ".gnu.hash",
elfcpp::SHT_GNU_HASH,
elfcpp::SHF_ALLOC,
- false, false, true);
+ false, false, true,
+ false, false,
+ false);
Output_section_data* hashdata = new Output_data_const_buffer(phash,
hashlen,
hashsec->add_output_section_data(hashdata);
hashsec->set_link_section(dynsym);
- hashsec->set_entsize(4);
+
+ // For a 64-bit target, the entries in .gnu.hash do not have a
+ // uniform size, so we only set the entry size for a 32-bit
+ // target.
+ if (parameters->target().get_size() == 32)
+ hashsec->set_entsize(4);
odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec);
}
Output_section* vsec = this->choose_output_section(NULL, ".gnu.version",
elfcpp::SHT_GNU_versym,
elfcpp::SHF_ALLOC,
- false, false, true);
+ false, false, true,
+ false, false, false);
unsigned char* vbuf;
unsigned int vsize;
vdsec= this->choose_output_section(NULL, ".gnu.version_d",
elfcpp::SHT_GNU_verdef,
elfcpp::SHF_ALLOC,
- false, false, true);
+ false, false, true, false, false,
+ false);
unsigned char* vdbuf;
unsigned int vdsize;
vnsec = this->choose_output_section(NULL, ".gnu.version_r",
elfcpp::SHT_GNU_verneed,
elfcpp::SHF_ALLOC,
- false, false, true);
+ false, false, true, false, false,
+ false);
unsigned char* vnbuf;
unsigned int vnsize;
Output_section* osec = this->choose_output_section(NULL, ".interp",
elfcpp::SHT_PROGBITS,
elfcpp::SHF_ALLOC,
- false, true, true);
+ false, true, true,
+ false, false, false);
osec->add_output_section_data(odata);
if (!this->script_options_->saw_phdrs_clause())
}
}
+// Add dynamic tags for the PLT and the dynamic relocs. This is
+// called by the target-specific code. This does nothing if not doing
+// a dynamic link.
+
+// USE_REL is true for REL relocs rather than RELA relocs.
+
+// If PLT_GOT is not NULL, then DT_PLTGOT points to it.
+
+// If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL,
+// and we also set DT_PLTREL. We use PLT_REL's output section, since
+// some targets have multiple reloc sections in PLT_REL.
+
+// If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
+// DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.
+
+// If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
+// executable.
+
+void
+Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got,
+ const Output_data* plt_rel,
+ const Output_data_reloc_generic* dyn_rel,
+ bool add_debug)
+{
+ Output_data_dynamic* odyn = this->dynamic_data_;
+ if (odyn == NULL)
+ return;
+
+ if (plt_got != NULL && plt_got->output_section() != NULL)
+ odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got);
+
+ if (plt_rel != NULL && plt_rel->output_section() != NULL)
+ {
+ odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section());
+ odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section());
+ odyn->add_constant(elfcpp::DT_PLTREL,
+ use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA);
+ }
+
+ if (dyn_rel != NULL && dyn_rel->output_section() != NULL)
+ {
+ odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
+ dyn_rel);
+ odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
+ dyn_rel);
+ const int size = parameters->target().get_size();
+ elfcpp::DT rel_tag;
+ int rel_size;
+ if (use_rel)
+ {
+ rel_tag = elfcpp::DT_RELENT;
+ if (size == 32)
+ rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size;
+ else if (size == 64)
+ rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size;
+ else
+ gold_unreachable();
+ }
+ else
+ {
+ rel_tag = elfcpp::DT_RELAENT;
+ if (size == 32)
+ rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size;
+ else if (size == 64)
+ rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size;
+ else
+ gold_unreachable();
+ }
+ odyn->add_constant(rel_tag, rel_size);
+
+ if (parameters->options().combreloc())
+ {
+ size_t c = dyn_rel->relative_reloc_count();
+ if (c > 0)
+ odyn->add_constant((use_rel
+ ? elfcpp::DT_RELCOUNT
+ : elfcpp::DT_RELACOUNT),
+ c);
+ }
+ }
+
+ if (add_debug && !parameters->options().shared())
+ {
+ // The value of the DT_DEBUG tag is filled in by the dynamic
+ // linker at run time, and used by the debugger.
+ odyn->add_constant(elfcpp::DT_DEBUG, 0);
+ }
+}
+
// Finish the .dynamic section and PT_DYNAMIC segment.
void
// Add a DT_TEXTREL for compatibility with older loaders.
odyn->add_constant(elfcpp::DT_TEXTREL, 0);
flags |= elfcpp::DF_TEXTREL;
+
+ if (parameters->options().text())
+ gold_error(_("read-only segment has dynamic relocations"));
+ else if (parameters->options().warn_shared_textrel()
+ && parameters->options().shared())
+ gold_warning(_("shared library text segment is not shareable"));
}
if (parameters->options().shared() && this->has_static_tls())
flags |= elfcpp::DF_STATIC_TLS;
odyn->add_constant(elfcpp::DT_FLAGS_1, flags);
}
+// Set the size of the _DYNAMIC symbol table to be the size of the
+// dynamic data.
+
+void
+Layout::set_dynamic_symbol_size(const Symbol_table* symtab)
+{
+ Output_data_dynamic* const odyn = this->dynamic_data_;
+ odyn->finalize_data_size();
+ off_t data_size = odyn->data_size();
+ const int size = parameters->target().get_size();
+ if (size == 32)
+ symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size);
+ else if (size == 64)
+ symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size);
+ else
+ gold_unreachable();
+}
+
// The mapping of input section name prefixes to output section names.
// In some cases one prefix is itself a prefix of another prefix; in
// such a case the longer prefix must come first. These prefixes are
projects / deliverable / binutils-gdb.git / blobdiff