// layout.cc -- lay out output file sections for gold
-// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
namespace gold
{
+// Class Free_list.
+
+// The total number of free lists used.
+unsigned int Free_list::num_lists = 0;
+// The total number of free list nodes used.
+unsigned int Free_list::num_nodes = 0;
+// The total number of calls to Free_list::remove.
+unsigned int Free_list::num_removes = 0;
+// The total number of nodes visited during calls to Free_list::remove.
+unsigned int Free_list::num_remove_visits = 0;
+// The total number of calls to Free_list::allocate.
+unsigned int Free_list::num_allocates = 0;
+// The total number of nodes visited during calls to Free_list::allocate.
+unsigned int Free_list::num_allocate_visits = 0;
+
+// Initialize the free list. Creates a single free list node that
+// describes the entire region of length LEN. If EXTEND is true,
+// allocate() is allowed to extend the region beyond its initial
+// length.
+
+void
+Free_list::init(off_t len, bool extend)
+{
+ this->list_.push_front(Free_list_node(0, len));
+ this->last_remove_ = this->list_.begin();
+ this->extend_ = extend;
+ this->length_ = len;
+ ++Free_list::num_lists;
+ ++Free_list::num_nodes;
+}
+
+// Remove a chunk from the free list. Because we start with a single
+// node that covers the entire section, and remove chunks from it one
+// at a time, we do not need to coalesce chunks or handle cases that
+// span more than one free node. We expect to remove chunks from the
+// free list in order, and we expect to have only a few chunks of free
+// space left (corresponding to files that have changed since the last
+// incremental link), so a simple linear list should provide sufficient
+// performance.
+
+void
+Free_list::remove(off_t start, off_t end)
+{
+ if (start == end)
+ return;
+ gold_assert(start < end);
+
+ ++Free_list::num_removes;
+
+ Iterator p = this->last_remove_;
+ if (p->start_ > start)
+ p = this->list_.begin();
+
+ for (; p != this->list_.end(); ++p)
+ {
+ ++Free_list::num_remove_visits;
+ // Find a node that wholly contains the indicated region.
+ if (p->start_ <= start && p->end_ >= end)
+ {
+ // Case 1: the indicated region spans the whole node.
+ // Add some fuzz to avoid creating tiny free chunks.
+ if (p->start_ + 3 >= start && p->end_ <= end + 3)
+ p = this->list_.erase(p);
+ // Case 2: remove a chunk from the start of the node.
+ else if (p->start_ + 3 >= start)
+ p->start_ = end;
+ // Case 3: remove a chunk from the end of the node.
+ else if (p->end_ <= end + 3)
+ p->end_ = start;
+ // Case 4: remove a chunk from the middle, and split
+ // the node into two.
+ else
+ {
+ Free_list_node newnode(p->start_, start);
+ p->start_ = end;
+ this->list_.insert(p, newnode);
+ ++Free_list::num_nodes;
+ }
+ this->last_remove_ = p;
+ return;
+ }
+ }
+
+ // Did not find a node containing the given chunk. This could happen
+ // because a small chunk was already removed due to the fuzz.
+ gold_debug(DEBUG_INCREMENTAL,
+ "Free_list::remove(%d,%d) not found",
+ static_cast<int>(start), static_cast<int>(end));
+}
+
+// Allocate a chunk of size LEN from the free list. Returns -1ULL
+// if a sufficiently large chunk of free space is not found.
+// We use a simple first-fit algorithm.
+
+off_t
+Free_list::allocate(off_t len, uint64_t align, off_t minoff)
+{
+ gold_debug(DEBUG_INCREMENTAL,
+ "Free_list::allocate(%08lx, %d, %08lx)",
+ static_cast<long>(len), static_cast<int>(align),
+ static_cast<long>(minoff));
+ if (len == 0)
+ return align_address(minoff, align);
+
+ ++Free_list::num_allocates;
+
+ for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
+ {
+ ++Free_list::num_allocate_visits;
+ off_t start = p->start_ > minoff ? p->start_ : minoff;
+ start = align_address(start, align);
+ off_t end = start + len;
+ if (end <= p->end_)
+ {
+ if (p->start_ + 3 >= start && p->end_ <= end + 3)
+ this->list_.erase(p);
+ else if (p->start_ + 3 >= start)
+ p->start_ = end;
+ else if (p->end_ <= end + 3)
+ p->end_ = start;
+ else
+ {
+ Free_list_node newnode(p->start_, start);
+ p->start_ = end;
+ this->list_.insert(p, newnode);
+ ++Free_list::num_nodes;
+ }
+ return start;
+ }
+ }
+ return -1;
+}
+
+// Dump the free list (for debugging).
+void
+Free_list::dump()
+{
+ gold_info("Free list:\n start end length\n");
+ for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p)
+ gold_info(" %08lx %08lx %08lx", static_cast<long>(p->start_),
+ static_cast<long>(p->end_),
+ static_cast<long>(p->end_ - p->start_));
+}
+
+// Print the statistics for the free lists.
+void
+Free_list::print_stats()
+{
+ fprintf(stderr, _("%s: total free lists: %u\n"),
+ program_name, Free_list::num_lists);
+ fprintf(stderr, _("%s: total free list nodes: %u\n"),
+ program_name, Free_list::num_nodes);
+ fprintf(stderr, _("%s: calls to Free_list::remove: %u\n"),
+ program_name, Free_list::num_removes);
+ fprintf(stderr, _("%s: nodes visited: %u\n"),
+ program_name, Free_list::num_remove_visits);
+ fprintf(stderr, _("%s: calls to Free_list::allocate: %u\n"),
+ program_name, Free_list::num_allocates);
+ fprintf(stderr, _("%s: nodes visited: %u\n"),
+ program_name, Free_list::num_allocate_visits);
+}
+
// Layout::Relaxation_debug_check methods.
// Check that sections and special data are in reset states.
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();
- of->open(file_size);
+ Output_file* of;
+ if (this->layout_->incremental_base() == NULL)
+ {
+ 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);
+ }
+ else
+ {
+ of = this->layout_->incremental_base()->output_file();
+ of->resize(file_size);
+ }
// Queue up the final set of tasks.
gold::queue_final_tasks(this->options_, this->input_objects_,
record_output_section_data_from_script_(false),
script_output_section_data_list_(),
segment_states_(NULL),
- relaxation_debug_check_(NULL)
+ relaxation_debug_check_(NULL),
+ incremental_base_(NULL),
+ free_list_()
{
// 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.
this->namepool_.set_optimize();
}
+// For incremental links, record the base file to be modified.
+
+void
+Layout::set_incremental_base(Incremental_binary* base)
+{
+ this->incremental_base_ = base;
+ this->free_list_.init(base->output_file()->filesize(), true);
+}
+
// Hash a key we use to look up an output section mapping.
size_t
return this->get_output_section(name, name_key, type, flags, order, is_relro);
}
+// For incremental links, record the initial fixed layout of a section
+// from the base file, and return a pointer to the Output_section.
+
+template<int size, bool big_endian>
+Output_section*
+Layout::init_fixed_output_section(const char* name,
+ elfcpp::Shdr<size, big_endian>& shdr)
+{
+ unsigned int sh_type = shdr.get_sh_type();
+
+ // We preserve the layout of PROGBITS, NOBITS, and NOTE sections.
+ // All others will be created from scratch and reallocated.
+ if (sh_type != elfcpp::SHT_PROGBITS
+ && sh_type != elfcpp::SHT_NOBITS
+ && sh_type != elfcpp::SHT_NOTE)
+ return NULL;
+
+ typename elfcpp::Elf_types<size>::Elf_Addr sh_addr = shdr.get_sh_addr();
+ typename elfcpp::Elf_types<size>::Elf_Off sh_offset = shdr.get_sh_offset();
+ typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size();
+ typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags();
+ typename elfcpp::Elf_types<size>::Elf_WXword sh_addralign =
+ shdr.get_sh_addralign();
+
+ // Make the output section.
+ Stringpool::Key name_key;
+ name = this->namepool_.add(name, true, &name_key);
+ Output_section* os = this->get_output_section(name, name_key, sh_type,
+ sh_flags, ORDER_INVALID, false);
+ os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign);
+ if (sh_type != elfcpp::SHT_NOBITS)
+ this->free_list_.remove(sh_offset, sh_offset + sh_size);
+ return os;
+}
+
// Return the output section to use for input section SHNDX, with name
// NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the
// index of a relocation section which applies to this section, or 0
this->eh_frame_section_ = os;
this->eh_frame_data_ = new Eh_frame();
- if (parameters->options().eh_frame_hdr())
+ // For incremental linking, we do not optimize .eh_frame sections
+ // or create a .eh_frame_hdr section.
+ if (parameters->options().eh_frame_hdr() && !parameters->incremental())
{
Output_section* hdr_os =
this->choose_output_section(NULL, ".eh_frame_hdr",
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))
+ if (!parameters->incremental()
+ && this->eh_frame_data_->add_ehframe_input_section(object,
+ symbols,
+ symbols_size,
+ symbol_names,
+ symbol_names_size,
+ shndx,
+ reloc_shndx,
+ reloc_type))
{
os->update_flags_for_input_section(shdr.get_sh_flags());
+ // A writable .eh_frame section is a RELRO section.
+ if ((shdr.get_sh_flags() & elfcpp::SHF_WRITE) != 0)
+ os->set_is_relro();
+
// 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
// object. On some targets that will force an executable stack.
void
-Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags)
+Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags,
+ const Object* obj)
{
if (!seen_gnu_stack)
- this->input_without_gnu_stack_note_ = true;
+ {
+ this->input_without_gnu_stack_note_ = true;
+ if (parameters->options().warn_execstack()
+ && parameters->target().is_default_stack_executable())
+ gold_warning(_("%s: missing .note.GNU-stack section"
+ " implies executable stack"),
+ obj->name().c_str());
+ }
else
{
this->input_with_gnu_stack_note_ = true;
if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0)
- this->input_requires_executable_stack_ = true;
+ {
+ this->input_requires_executable_stack_ = true;
+ if (parameters->options().warn_execstack()
+ || parameters->options().is_stack_executable())
+ gold_warning(_("%s: requires executable stack"),
+ obj->name().c_str());
+ }
}
}
void
Layout::create_gold_note()
{
- if (parameters->options().relocatable())
+ if (parameters->options().relocatable()
+ || parameters->incremental_update())
return;
std::string desc = std::string("gold ") + gold::get_version_string();
unsigned int shndx_hold = *pshndx;
bool has_relro = false;
uint64_t new_addr = (*p)->set_section_addresses(this, false, addr,
- increase_relro,
+ &increase_relro,
&has_relro,
&off, pshndx);
// aligned so that the relro data ends at a page boundary,
// we do not try to realign it.
- if (!are_addresses_set && !has_relro && aligned_addr != addr)
+ if (!are_addresses_set
+ && !has_relro
+ && aligned_addr != addr
+ && !parameters->incremental_update())
{
uint64_t first_off = (common_pagesize
- (aligned_addr
addr = align_address(addr, (*p)->maximum_alignment());
off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1));
off = align_file_offset(off, addr, abi_pagesize);
+
+ increase_relro = this->increase_relro_;
+ if (this->script_options_->saw_sections_clause())
+ increase_relro = 0;
+ has_relro = false;
+
new_addr = (*p)->set_section_addresses(this, true, addr,
- increase_relro,
+ &increase_relro,
&has_relro,
&off, pshndx);
}
off_t
Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass)
{
+ off_t startoff = off;
+ off_t maxoff = off;
+
for (Section_list::iterator p = this->unattached_section_list_.begin();
p != this->unattached_section_list_.end();
++p)
|| (*p)->type() != elfcpp::SHT_STRTAB))
continue;
- off = align_address(off, (*p)->addralign());
- (*p)->set_file_offset(off);
- (*p)->finalize_data_size();
+ if (!parameters->incremental_update())
+ {
+ off = align_address(off, (*p)->addralign());
+ (*p)->set_file_offset(off);
+ (*p)->finalize_data_size();
+ }
+ else
+ {
+ // Incremental update: allocate file space from free list.
+ (*p)->pre_finalize_data_size();
+ off_t current_size = (*p)->current_data_size();
+ off = this->allocate(current_size, (*p)->addralign(), startoff);
+ if (off == -1)
+ {
+ if (is_debugging_enabled(DEBUG_INCREMENTAL))
+ this->free_list_.dump();
+ gold_assert((*p)->output_section() != NULL);
+ gold_fatal(_("out of patch space for section %s; "
+ "relink with --incremental-full"),
+ (*p)->output_section()->name());
+ }
+ (*p)->set_file_offset(off);
+ (*p)->finalize_data_size();
+ if ((*p)->data_size() > current_size)
+ {
+ gold_assert((*p)->output_section() != NULL);
+ gold_fatal(_("%s: section changed size; "
+ "relink with --incremental-full"),
+ (*p)->output_section()->name());
+ }
+ gold_debug(DEBUG_INCREMENTAL,
+ "set_section_offsets: %08lx %08lx %s",
+ static_cast<long>(off),
+ static_cast<long>((*p)->data_size()),
+ ((*p)->output_section() != NULL
+ ? (*p)->output_section()->name() : "(special)"));
+ }
+
off += (*p)->data_size();
+ if (off > maxoff)
+ maxoff = off;
// At this point the name must be set.
if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS)
this->namepool_.add((*p)->name(), false, NULL);
}
- return off;
+ return maxoff;
}
// Set the section indexes of all the sections not associated with a
else
gold_unreachable();
- off_t off = *poff;
- off = align_address(off, align);
- off_t startoff = off;
+ // Compute file offsets relative to the start of the symtab section.
+ off_t off = 0;
// Save space for the dummy symbol at the start of the section. We
// never bother to write this out--it will just be left as zero.
}
unsigned int local_symcount = local_symbol_index;
- gold_assert(static_cast<off_t>(local_symcount * symsize) == off - startoff);
+ gold_assert(static_cast<off_t>(local_symcount * symsize) == off);
off_t dynoff;
size_t dyn_global_index;
== this->dynsym_section_->data_size() - locsize);
}
+ off_t global_off = off;
off = symtab->finalize(off, dynoff, dyn_global_index, dyncount,
&this->sympool_, &local_symcount);
false);
this->symtab_section_ = osymtab;
- Output_section_data* pos = new Output_data_fixed_space(off - startoff,
- align,
+ Output_section_data* pos = new Output_data_fixed_space(off, align,
"** symtab");
osymtab->add_output_section_data(pos);
elfcpp::SHT_SYMTAB_SHNDX, 0,
ORDER_INVALID, false);
- size_t symcount = (off - startoff) / symsize;
+ size_t symcount = off / symsize;
this->symtab_xindex_ = new Output_symtab_xindex(symcount);
osymtab_xindex->add_output_section_data(this->symtab_xindex_);
Output_section_data* pstr = new Output_data_strtab(&this->sympool_);
ostrtab->add_output_section_data(pstr);
- osymtab->set_file_offset(startoff);
+ off_t symtab_off;
+ if (!parameters->incremental_update())
+ symtab_off = align_address(*poff, align);
+ else
+ {
+ symtab_off = this->allocate(off, align, *poff);
+ if (off == -1)
+ gold_fatal(_("out of patch space for symbol table; "
+ "relink with --incremental-full"));
+ gold_debug(DEBUG_INCREMENTAL,
+ "create_symtab_sections: %08lx %08lx .symtab",
+ static_cast<long>(symtab_off),
+ static_cast<long>(off));
+ }
+
+ symtab->set_file_offset(symtab_off + global_off);
+ osymtab->set_file_offset(symtab_off);
osymtab->finalize_data_size();
osymtab->set_link_section(ostrtab);
osymtab->set_info(local_symcount);
osymtab->set_entsize(symsize);
- *poff = off;
+ if (symtab_off + off > *poff)
+ *poff = symtab_off + off;
}
}
&this->unattached_section_list_,
&this->namepool_,
shstrtab_section);
- off_t off = align_address(*poff, oshdrs->addralign());
+ off_t off;
+ if (!parameters->incremental_update())
+ off = align_address(*poff, oshdrs->addralign());
+ else
+ {
+ oshdrs->pre_finalize_data_size();
+ off = this->allocate(oshdrs->data_size(), oshdrs->addralign(), *poff);
+ if (off == -1)
+ gold_fatal(_("out of patch space for section header table; "
+ "relink with --incremental-full"));
+ gold_debug(DEBUG_INCREMENTAL,
+ "create_shdrs: %08lx %08lx (section header table)",
+ static_cast<long>(off),
+ static_cast<long>(off + oshdrs->data_size()));
+ }
oshdrs->set_address_and_file_offset(0, off);
off += oshdrs->data_size();
- *poff = off;
+ if (off > *poff)
+ *poff = off;
this->section_headers_ = oshdrs;
}
++p)
{
if (!(*p)->is_needed()
+ && !(*p)->is_incremental()
&& (*p)->input_file()->options().as_needed())
{
// This dynamic object was linked with --as-needed, but it
return oseg;
}
+// Return the file offset of the normal symbol table.
+
+off_t
+Layout::symtab_section_offset() const
+{
+ if (this->symtab_section_ != NULL)
+ return this->symtab_section_->offset();
+ return 0;
+}
+
// 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.
// 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::init_fixed_output_section<32, false>(
+ const char* name,
+ elfcpp::Shdr<32, false>& shdr);
+#endif
+
+#ifdef HAVE_TARGET_32_BIG
+template
+Output_section*
+Layout::init_fixed_output_section<32, true>(
+ const char* name,
+ elfcpp::Shdr<32, true>& shdr);
+#endif
+
+#ifdef HAVE_TARGET_64_LITTLE
+template
+Output_section*
+Layout::init_fixed_output_section<64, false>(
+ const char* name,
+ elfcpp::Shdr<64, false>& shdr);
+#endif
+
+#ifdef HAVE_TARGET_64_BIG
+template
+Output_section*
+Layout::init_fixed_output_section<64, true>(
+ const char* name,
+ elfcpp::Shdr<64, true>& shdr);
+#endif
+
#ifdef HAVE_TARGET_32_LITTLE
template
Output_section*
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