// layout.cc -- lay out output file sections for gold
-// Copyright (C) 2006-2017 Free Software Foundation, Inc.
+// Copyright (C) 2006-2020 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
unique_segment_for_sections_specified_(false),
incremental_inputs_(NULL),
record_output_section_data_from_script_(false),
+ lto_slim_object_(false),
script_output_section_data_list_(),
segment_states_(NULL),
relaxation_debug_check_(NULL),
input_section_position_(),
input_section_glob_(),
incremental_base_(NULL),
- free_list_()
+ free_list_(),
+ gnu_properties_()
{
// 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.
".text.unlikely",
".text.exit",
".text.startup",
- ".text.hot"
+ ".text.hot",
+ ".text.sorted"
};
for (size_t i = 0;
Output_section*
Layout::layout(Sized_relobj_file<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)
+ unsigned int sh_type, unsigned int reloc_shndx,
+ unsigned int, off_t* off)
{
*off = 0;
if (!this->include_section(object, name, shdr))
return NULL;
- elfcpp::Elf_Word sh_type = shdr.get_sh_type();
-
// In a relocatable link a grouped section must not be combined with
// any other sections.
Output_section* os;
}
else
{
- // Plugins can choose to place one or more subsets of sections in
- // unique segments and this is done by mapping these section subsets
- // to unique output sections. Check if this section needs to be
- // remapped to a unique output section.
- Section_segment_map::iterator it
- = this->section_segment_map_.find(Const_section_id(object, shndx));
- if (it == this->section_segment_map_.end())
- {
- os = this->choose_output_section(object, name, sh_type,
- shdr.get_sh_flags(), true,
- ORDER_INVALID, false, false,
- true);
- }
- else
- {
- // We know the name of the output section, directly call
- // get_output_section here by-passing choose_output_section.
+ // All ".text.unlikely.*" sections can be moved to a unique
+ // segment with --text-unlikely-segment option.
+ bool text_unlikely_segment
+ = (parameters->options().text_unlikely_segment()
+ && is_prefix_of(".text.unlikely",
+ object->section_name(shndx).c_str()));
+ if (text_unlikely_segment)
+ {
elfcpp::Elf_Xword flags
= this->get_output_section_flags(shdr.get_sh_flags());
- const char* os_name = it->second->name;
Stringpool::Key name_key;
- os_name = this->namepool_.add(os_name, true, &name_key);
+ const char* os_name = this->namepool_.add(".text.unlikely", true,
+ &name_key);
os = this->get_output_section(os_name, name_key, sh_type, flags,
ORDER_INVALID, false);
- if (!os->is_unique_segment())
+ // Map this output section to a unique segment. This is done to
+ // separate "text" that is not likely to be executed from "text"
+ // that is likely executed.
+ os->set_is_unique_segment();
+ }
+ else
+ {
+ // Plugins can choose to place one or more subsets of sections in
+ // unique segments and this is done by mapping these section subsets
+ // to unique output sections. Check if this section needs to be
+ // remapped to a unique output section.
+ Section_segment_map::iterator it
+ = this->section_segment_map_.find(Const_section_id(object, shndx));
+ if (it == this->section_segment_map_.end())
{
- os->set_is_unique_segment();
- os->set_extra_segment_flags(it->second->flags);
- os->set_segment_alignment(it->second->align);
+ os = this->choose_output_section(object, name, sh_type,
+ shdr.get_sh_flags(), true,
+ ORDER_INVALID, false, false,
+ true);
}
- }
+ else
+ {
+ // We know the name of the output section, directly call
+ // get_output_section here by-passing choose_output_section.
+ elfcpp::Elf_Xword flags
+ = this->get_output_section_flags(shdr.get_sh_flags());
+
+ const char* os_name = it->second->name;
+ Stringpool::Key name_key;
+ os_name = this->namepool_.add(os_name, true, &name_key);
+ os = this->get_output_section(os_name, name_key, sh_type, flags,
+ ORDER_INVALID, false);
+ if (!os->is_unique_segment())
+ {
+ os->set_is_unique_segment();
+ os->set_extra_segment_flags(it->second->flags);
+ os->set_segment_alignment(it->second->align);
+ }
+ }
+ }
if (os == NULL)
return NULL;
}
template<int size, bool big_endian>
Output_section*
-Layout::layout_reloc(Sized_relobj_file<size, big_endian>* object,
+Layout::layout_reloc(Sized_relobj_file<size, big_endian>*,
unsigned int,
const elfcpp::Shdr<size, big_endian>& shdr,
Output_section* data_section,
gold_unreachable();
name += data_section->name();
- // In a relocatable link relocs for a grouped section must not be
- // combined with other reloc sections.
- Output_section* os;
- if (!parameters->options().relocatable()
- || (data_section->flags() & elfcpp::SHF_GROUP) == 0)
- os = this->choose_output_section(object, name.c_str(), sh_type,
- shdr.get_sh_flags(), false,
- ORDER_INVALID, false, true, false);
- else
+ // If the output data section already has a reloc section, use that;
+ // otherwise, make a new one.
+ Output_section* os = data_section->reloc_section();
+ if (os == NULL)
{
const char* n = this->namepool_.add(name.c_str(), true, NULL);
os = this->make_output_section(n, sh_type, shdr.get_sh_flags(),
ORDER_INVALID, false);
+ os->set_should_link_to_symtab();
+ os->set_info_section(data_section);
+ data_section->set_reloc_section(os);
}
- os->set_should_link_to_symtab();
- os->set_info_section(data_section);
-
Output_section_data* posd;
if (sh_type == elfcpp::SHT_REL)
{
unsigned int reloc_shndx, unsigned int reloc_type,
off_t* off)
{
+ const unsigned int unwind_section_type =
+ parameters->target().unwind_section_type();
+
gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS
- || shdr.get_sh_type() == elfcpp::SHT_X86_64_UNWIND);
+ || shdr.get_sh_type() == unwind_section_type);
gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0);
Output_section* os = this->make_eh_frame_section(object);
Output_section*
Layout::make_eh_frame_section(const Relobj* object)
{
- // FIXME: On x86_64, this could use SHT_X86_64_UNWIND rather than
- // SHT_PROGBITS.
+ const unsigned int unwind_section_type =
+ parameters->target().unwind_section_type();
+
Output_section* os = this->choose_output_section(object, ".eh_frame",
- elfcpp::SHT_PROGBITS,
+ unwind_section_type,
elfcpp::SHF_ALLOC, false,
ORDER_EHFRAME, false, false,
false);
{
Output_section* hdr_os =
this->choose_output_section(NULL, ".eh_frame_hdr",
- elfcpp::SHT_PROGBITS,
+ unwind_section_type,
elfcpp::SHF_ALLOC, false,
ORDER_EHFRAME, false, false,
false);
}
}
+// Remove all post-map .eh_frame information for a PLT.
+
+void
+Layout::remove_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data,
+ size_t cie_length)
+{
+ if (parameters->incremental())
+ {
+ // FIXME: Maybe this could work some day....
+ return;
+ }
+ this->eh_frame_data_->remove_ehframe_for_plt(plt, cie_data, cie_length);
+}
+
// Scan a .debug_info or .debug_types section, and add summary
// information to the .gdb_index section.
return ORDER_INIT;
else if (strcmp(os->name(), ".fini") == 0)
return ORDER_FINI;
+ else if (parameters->options().keep_text_section_prefix())
+ {
+ // -z,keep-text-section-prefix introduces additional
+ // output sections.
+ if (strcmp(os->name(), ".text.hot") == 0)
+ return ORDER_TEXT_HOT;
+ else if (strcmp(os->name(), ".text.startup") == 0)
+ return ORDER_TEXT_STARTUP;
+ else if (strcmp(os->name(), ".text.exit") == 0)
+ return ORDER_TEXT_EXIT;
+ else if (strcmp(os->name(), ".text.unlikely") == 0)
+ return ORDER_TEXT_UNLIKELY;
+ }
}
return is_execinstr ? ORDER_TEXT : ORDER_READONLY;
}
}
}
+// Read a value with given size and endianness.
+
+static inline uint64_t
+read_sized_value(size_t size, const unsigned char* buf, bool is_big_endian,
+ const Object* object)
+{
+ uint64_t val = 0;
+ if (size == 4)
+ {
+ if (is_big_endian)
+ val = elfcpp::Swap<32, true>::readval(buf);
+ else
+ val = elfcpp::Swap<32, false>::readval(buf);
+ }
+ else if (size == 8)
+ {
+ if (is_big_endian)
+ val = elfcpp::Swap<64, true>::readval(buf);
+ else
+ val = elfcpp::Swap<64, false>::readval(buf);
+ }
+ else
+ {
+ gold_warning(_("%s: in .note.gnu.property section, "
+ "pr_datasz must be 4 or 8"),
+ object->name().c_str());
+ }
+ return val;
+}
+
+// Write a value with given size and endianness.
+
+static inline void
+write_sized_value(uint64_t value, size_t size, unsigned char* buf,
+ bool is_big_endian)
+{
+ if (size == 4)
+ {
+ if (is_big_endian)
+ elfcpp::Swap<32, true>::writeval(buf, static_cast<uint32_t>(value));
+ else
+ elfcpp::Swap<32, false>::writeval(buf, static_cast<uint32_t>(value));
+ }
+ else if (size == 8)
+ {
+ if (is_big_endian)
+ elfcpp::Swap<64, true>::writeval(buf, value);
+ else
+ elfcpp::Swap<64, false>::writeval(buf, value);
+ }
+ else
+ {
+ // We will have already complained about this.
+ }
+}
+
+// Handle the .note.gnu.property section at layout time.
+
+void
+Layout::layout_gnu_property(unsigned int note_type,
+ unsigned int pr_type,
+ size_t pr_datasz,
+ const unsigned char* pr_data,
+ const Object* object)
+{
+ // We currently support only the one note type.
+ gold_assert(note_type == elfcpp::NT_GNU_PROPERTY_TYPE_0);
+
+ if (pr_type >= elfcpp::GNU_PROPERTY_LOPROC
+ && pr_type < elfcpp::GNU_PROPERTY_HIPROC)
+ {
+ // Target-dependent property value; call the target to record.
+ const int size = parameters->target().get_size();
+ const bool is_big_endian = parameters->target().is_big_endian();
+ if (size == 32)
+ {
+ if (is_big_endian)
+ {
+#ifdef HAVE_TARGET_32_BIG
+ parameters->sized_target<32, true>()->
+ record_gnu_property(note_type, pr_type, pr_datasz, pr_data,
+ object);
+#else
+ gold_unreachable();
+#endif
+ }
+ else
+ {
+#ifdef HAVE_TARGET_32_LITTLE
+ parameters->sized_target<32, false>()->
+ record_gnu_property(note_type, pr_type, pr_datasz, pr_data,
+ object);
+#else
+ gold_unreachable();
+#endif
+ }
+ }
+ else if (size == 64)
+ {
+ if (is_big_endian)
+ {
+#ifdef HAVE_TARGET_64_BIG
+ parameters->sized_target<64, true>()->
+ record_gnu_property(note_type, pr_type, pr_datasz, pr_data,
+ object);
+#else
+ gold_unreachable();
+#endif
+ }
+ else
+ {
+#ifdef HAVE_TARGET_64_LITTLE
+ parameters->sized_target<64, false>()->
+ record_gnu_property(note_type, pr_type, pr_datasz, pr_data,
+ object);
+#else
+ gold_unreachable();
+#endif
+ }
+ }
+ else
+ gold_unreachable();
+ return;
+ }
+
+ Gnu_properties::iterator pprop = this->gnu_properties_.find(pr_type);
+ if (pprop == this->gnu_properties_.end())
+ {
+ Gnu_property prop;
+ prop.pr_datasz = pr_datasz;
+ prop.pr_data = new unsigned char[pr_datasz];
+ memcpy(prop.pr_data, pr_data, pr_datasz);
+ this->gnu_properties_[pr_type] = prop;
+ }
+ else
+ {
+ const bool is_big_endian = parameters->target().is_big_endian();
+ switch (pr_type)
+ {
+ case elfcpp::GNU_PROPERTY_STACK_SIZE:
+ // Record the maximum value seen.
+ {
+ uint64_t val1 = read_sized_value(pprop->second.pr_datasz,
+ pprop->second.pr_data,
+ is_big_endian, object);
+ uint64_t val2 = read_sized_value(pr_datasz, pr_data,
+ is_big_endian, object);
+ if (val2 > val1)
+ write_sized_value(val2, pprop->second.pr_datasz,
+ pprop->second.pr_data, is_big_endian);
+ }
+ break;
+ case elfcpp::GNU_PROPERTY_NO_COPY_ON_PROTECTED:
+ // No data to merge.
+ break;
+ default:
+ gold_warning(_("%s: unknown program property type %d "
+ "in .note.gnu.property section"),
+ object->name().c_str(), pr_type);
+ }
+ }
+}
+
+// Merge per-object properties with program properties.
+// This lets the target identify objects that are missing certain
+// properties, in cases where properties must be ANDed together.
+
+void
+Layout::merge_gnu_properties(const Object* object)
+{
+ const int size = parameters->target().get_size();
+ const bool is_big_endian = parameters->target().is_big_endian();
+ if (size == 32)
+ {
+ if (is_big_endian)
+ {
+#ifdef HAVE_TARGET_32_BIG
+ parameters->sized_target<32, true>()->merge_gnu_properties(object);
+#else
+ gold_unreachable();
+#endif
+ }
+ else
+ {
+#ifdef HAVE_TARGET_32_LITTLE
+ parameters->sized_target<32, false>()->merge_gnu_properties(object);
+#else
+ gold_unreachable();
+#endif
+ }
+ }
+ else if (size == 64)
+ {
+ if (is_big_endian)
+ {
+#ifdef HAVE_TARGET_64_BIG
+ parameters->sized_target<64, true>()->merge_gnu_properties(object);
+#else
+ gold_unreachable();
+#endif
+ }
+ else
+ {
+#ifdef HAVE_TARGET_64_LITTLE
+ parameters->sized_target<64, false>()->merge_gnu_properties(object);
+#else
+ gold_unreachable();
+#endif
+ }
+ }
+ else
+ gold_unreachable();
+}
+
+// Add a target-specific property for the output .note.gnu.property section.
+
+void
+Layout::add_gnu_property(unsigned int note_type,
+ unsigned int pr_type,
+ size_t pr_datasz,
+ const unsigned char* pr_data)
+{
+ gold_assert(note_type == elfcpp::NT_GNU_PROPERTY_TYPE_0);
+
+ Gnu_property prop;
+ prop.pr_datasz = pr_datasz;
+ prop.pr_data = new unsigned char[pr_datasz];
+ memcpy(prop.pr_data, pr_data, pr_datasz);
+ this->gnu_properties_[pr_type] = prop;
+}
+
// Create automatic note sections.
void
Layout::create_notes()
{
+ this->create_gnu_properties_note();
this->create_gold_note();
this->create_stack_segment();
this->create_build_id();
0, // symsize
elfcpp::STT_NOTYPE,
elfcpp::STB_GLOBAL,
- elfcpp::STV_DEFAULT,
+ elfcpp::STV_PROTECTED,
0, // nonvis
false, // offset_is_from_end
true); // only_if_ref
0, // symsize
elfcpp::STT_NOTYPE,
elfcpp::STB_GLOBAL,
- elfcpp::STV_DEFAULT,
+ elfcpp::STV_PROTECTED,
0, // nonvis
true, // offset_is_from_end
true); // only_if_ref
return os;
}
+// Create a .note.gnu.property section to record program properties
+// accumulated from the input files.
+
+void
+Layout::create_gnu_properties_note()
+{
+ parameters->target().finalize_gnu_properties(this);
+
+ if (this->gnu_properties_.empty())
+ return;
+
+ const unsigned int size = parameters->target().get_size();
+ const bool is_big_endian = parameters->target().is_big_endian();
+
+ // Compute the total size of the properties array.
+ size_t descsz = 0;
+ for (Gnu_properties::const_iterator prop = this->gnu_properties_.begin();
+ prop != this->gnu_properties_.end();
+ ++prop)
+ {
+ descsz = align_address(descsz + 8 + prop->second.pr_datasz, size / 8);
+ }
+
+ // Create the note section.
+ size_t trailing_padding;
+ Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_PROPERTY_TYPE_0,
+ ".note.gnu.property", descsz,
+ true, &trailing_padding);
+ if (os == NULL)
+ return;
+ gold_assert(trailing_padding == 0);
+
+ // Allocate and fill the properties array.
+ unsigned char* desc = new unsigned char[descsz];
+ unsigned char* p = desc;
+ for (Gnu_properties::const_iterator prop = this->gnu_properties_.begin();
+ prop != this->gnu_properties_.end();
+ ++prop)
+ {
+ size_t datasz = prop->second.pr_datasz;
+ size_t aligned_datasz = align_address(prop->second.pr_datasz, size / 8);
+ write_sized_value(prop->first, 4, p, is_big_endian);
+ write_sized_value(datasz, 4, p + 4, is_big_endian);
+ memcpy(p + 8, prop->second.pr_data, datasz);
+ if (aligned_datasz > datasz)
+ memset(p + 8 + datasz, 0, aligned_datasz - datasz);
+ p += 8 + aligned_datasz;
+ }
+ Output_section_data* posd = new Output_data_const(desc, descsz, 4);
+ os->add_output_section_data(posd);
+}
+
// For an executable or shared library, create a note to record the
// version of gold used to create the binary.
// here if plugins want unique segments for subsets of sections.
gold_assert(this->script_options_->saw_phdrs_clause()
|| parameters->options().any_section_start()
- || this->is_unique_segment_for_sections_specified());
+ || this->is_unique_segment_for_sections_specified()
+ || parameters->options().text_unlikely_segment());
return false;
}
MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"),
MAPPING_INIT(".ARM.exidx", ".ARM.exidx"),
MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"),
+ MAPPING_INIT(".gnu.build.attributes.", ".gnu.build.attributes"),
+};
+
+// Mapping for ".text" section prefixes with -z,keep-text-section-prefix.
+const Layout::Section_name_mapping Layout::text_section_name_mapping[] =
+{
+ MAPPING_INIT(".text.hot.", ".text.hot"),
+ MAPPING_INIT_EXACT(".text.hot", ".text.hot"),
+ MAPPING_INIT(".text.unlikely.", ".text.unlikely"),
+ MAPPING_INIT_EXACT(".text.unlikely", ".text.unlikely"),
+ MAPPING_INIT(".text.startup.", ".text.startup"),
+ MAPPING_INIT_EXACT(".text.startup", ".text.startup"),
+ MAPPING_INIT(".text.exit.", ".text.exit"),
+ MAPPING_INIT_EXACT(".text.exit", ".text.exit"),
+ MAPPING_INIT(".text.", ".text"),
};
#undef MAPPING_INIT
#undef MAPPING_INIT_EXACT
(sizeof(Layout::section_name_mapping)
/ sizeof(Layout::section_name_mapping[0]));
+const int Layout::text_section_name_mapping_count =
+ (sizeof(Layout::text_section_name_mapping)
+ / sizeof(Layout::text_section_name_mapping[0]));
+
+// Find section name NAME in PSNM and return the mapped name if found
+// with the length set in PLEN.
+const char *
+Layout::match_section_name(const Layout::Section_name_mapping* psnm,
+ const int count,
+ const char* name, size_t* plen)
+{
+ for (int i = 0; i < count; ++i, ++psnm)
+ {
+ if (psnm->fromlen > 0)
+ {
+ if (strncmp(name, psnm->from, psnm->fromlen) == 0)
+ {
+ *plen = psnm->tolen;
+ return psnm->to;
+ }
+ }
+ else
+ {
+ if (strcmp(name, psnm->from) == 0)
+ {
+ *plen = psnm->tolen;
+ return psnm->to;
+ }
+ }
+ }
+ return NULL;
+}
+
// Choose the output section name to use given an input section name.
// Set *PLEN to the length of the name. *PLEN is initialized to the
// length of NAME.
// not found in the table, we simply use it as the output section
// name.
- const Section_name_mapping* psnm = section_name_mapping;
- for (int i = 0; i < section_name_mapping_count; ++i, ++psnm)
+ if (parameters->options().keep_text_section_prefix()
+ && is_prefix_of(".text", name))
{
- if (psnm->fromlen > 0)
- {
- if (strncmp(name, psnm->from, psnm->fromlen) == 0)
- {
- *plen = psnm->tolen;
- return psnm->to;
- }
- }
- else
- {
- if (strcmp(name, psnm->from) == 0)
- {
- *plen = psnm->tolen;
- return psnm->to;
- }
- }
+ const char* match = match_section_name(text_section_name_mapping,
+ text_section_name_mapping_count,
+ name, plen);
+ if (match != NULL)
+ return match;
}
+ const char* match = match_section_name(section_name_mapping,
+ section_name_mapping_count, name, plen);
+ if (match != NULL)
+ return match;
+
// As an additional complication, .ctors sections are output in
// either .ctors or .init_array sections, and .dtors sections are
// output in either .dtors or .fini_array sections.
unsigned int shndx,
const char* name,
const elfcpp::Shdr<32, false>& shdr,
- unsigned int, unsigned int, off_t*);
+ unsigned int, unsigned int, unsigned int, off_t*);
#endif
#ifdef HAVE_TARGET_32_BIG
unsigned int shndx,
const char* name,
const elfcpp::Shdr<32, true>& shdr,
- unsigned int, unsigned int, off_t*);
+ unsigned int, unsigned int, unsigned int, off_t*);
#endif
#ifdef HAVE_TARGET_64_LITTLE
unsigned int shndx,
const char* name,
const elfcpp::Shdr<64, false>& shdr,
- unsigned int, unsigned int, off_t*);
+ unsigned int, unsigned int, unsigned int, off_t*);
#endif
#ifdef HAVE_TARGET_64_BIG
unsigned int shndx,
const char* name,
const elfcpp::Shdr<64, true>& shdr,
- unsigned int, unsigned int, off_t*);
+ unsigned int, unsigned int, unsigned int, off_t*);
#endif
#ifdef HAVE_TARGET_32_LITTLE
projects / deliverable / binutils-gdb.git / blobdiff