// reloc.cc -- relocate input files for gold.
-// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
{
Read_relocs_data *rd = new Read_relocs_data;
this->object_->read_relocs(rd);
+ this->object_->set_relocs_data(rd);
this->object_->release();
- workqueue->queue_next(new Scan_relocs(this->options_, this->symtab_,
- this->layout_, this->object_, rd,
- this->symtab_lock_, this->blocker_));
+ // If garbage collection or identical comdat folding is desired, we
+ // process the relocs first before scanning them. Scanning of relocs is
+ // done only after garbage or identical sections is identified.
+ if (parameters->options().gc_sections() || parameters->options().icf())
+ {
+ workqueue->queue_next(new Gc_process_relocs(this->options_,
+ this->symtab_,
+ this->layout_,
+ this->object_, rd,
+ this->symtab_lock_,
+ this->blocker_));
+ }
+ else
+ {
+ workqueue->queue_next(new Scan_relocs(this->options_, this->symtab_,
+ this->layout_, this->object_, rd,
+ this->symtab_lock_,
+ this->blocker_));
+ }
}
// Return a debugging name for the task.
return "Read_relocs " + this->object_->name();
}
+// Gc_process_relocs methods.
+
+// These tasks process the relocations read by Read_relocs and
+// determine which sections are referenced and which are garbage.
+// This task is done only when --gc-sections is used.
+
+Task_token*
+Gc_process_relocs::is_runnable()
+{
+ if (this->object_->is_locked())
+ return this->object_->token();
+ return NULL;
+}
+
+void
+Gc_process_relocs::locks(Task_locker* tl)
+{
+ tl->add(this, this->object_->token());
+ tl->add(this, this->blocker_);
+}
+
+void
+Gc_process_relocs::run(Workqueue*)
+{
+ this->object_->gc_process_relocs(this->options_, this->symtab_, this->layout_,
+ this->rd_);
+ this->object_->release();
+}
+
+// Return a debugging name for the task.
+
+std::string
+Gc_process_relocs::get_name() const
+{
+ return "Gc_process_relocs " + this->object_->name();
+}
+
// Scan_relocs methods.
// These tasks scan the relocations read by Read_relocs and mark up
// PLT sections. Relocations for sections which are not
// allocated (typically debugging sections) should not add new
// GOT and PLT entries. So we skip them unless this is a
- // relocatable link or we need to emit relocations.
+ // relocatable link or we need to emit relocations. FIXME: What
+ // should we do if a linker script maps a section with SHF_ALLOC
+ // clear to a section with SHF_ALLOC set?
typename This::Shdr secshdr(pshdrs + shndx * This::shdr_size);
bool is_section_allocated = ((secshdr.get_sh_flags() & elfcpp::SHF_ALLOC)
!= 0);
}
}
+// Process the relocs to generate mappings from source sections to referenced
+// sections. This is used during garbage colletion to determine garbage
+// sections.
+
+template<int size, bool big_endian>
+void
+Sized_relobj<size, big_endian>::do_gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Read_relocs_data* rd)
+{
+ Sized_target<size, big_endian>* target =
+ parameters->sized_target<size, big_endian>();
+
+ const unsigned char* local_symbols;
+ if (rd->local_symbols == NULL)
+ local_symbols = NULL;
+ else
+ local_symbols = rd->local_symbols->data();
+
+ for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
+ p != rd->relocs.end();
+ ++p)
+ {
+ if (!parameters->options().relocatable())
+ {
+ // As noted above, when not generating an object file, we
+ // only scan allocated sections. We may see a non-allocated
+ // section here if we are emitting relocs.
+ if (p->is_data_section_allocated)
+ target->gc_process_relocs(options, symtab, layout, this,
+ p->data_shndx, p->sh_type,
+ p->contents->data(), p->reloc_count,
+ p->output_section,
+ p->needs_special_offset_handling,
+ this->local_symbol_count_,
+ local_symbols);
+ }
+ }
+}
+
+
// Scan the relocs and adjust the symbol table. This looks for
// relocations which require GOT/PLT/COPY relocations.
Layout* layout,
Read_relocs_data* rd)
{
- Sized_target<size, big_endian>* target = this->sized_target();
+ Sized_target<size, big_endian>* target =
+ parameters->sized_target<size, big_endian>();
const unsigned char* local_symbols;
if (rd->local_symbols == NULL)
p != rd->relocs.end();
++p)
{
+ // When garbage collection is on, unreferenced sections are not included
+ // in the link that would have been included normally. This is known only
+ // after Read_relocs hence this check has to be done again.
+ if (parameters->options().gc_sections() || parameters->options().icf())
+ {
+ if (p->output_section == NULL)
+ continue;
+ }
if (!parameters->options().relocatable())
{
// As noted above, when not generating an object file, we
Views* pviews)
{
unsigned int shnum = this->shnum();
- Sized_target<size, big_endian>* target = this->sized_target();
+ Sized_target<size, big_endian>* target =
+ parameters->sized_target<size, big_endian>();
const Output_sections& out_sections(this->output_sections());
const std::vector<Address>& out_offsets(this->section_offsets_);
if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
continue;
+ off_t sh_size = shdr.get_sh_size();
+ if (sh_size == 0)
+ continue;
+
unsigned int index = this->adjust_shndx(shdr.get_sh_info());
if (index >= this->shnum())
{
continue;
}
- off_t sh_size = shdr.get_sh_size();
const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
sh_size, true, false);
relinfo.reloc_shndx = i;
relinfo.data_shndx = index;
+ unsigned char* view = (*pviews)[index].view;
+ Address address = (*pviews)[index].address;
+ section_size_type view_size = (*pviews)[index].view_size;
+
+ Reloc_symbol_changes* reloc_map = NULL;
+ if (this->uses_split_stack() && output_offset != invalid_address)
+ {
+ typename This::Shdr data_shdr(pshdrs + index * This::shdr_size);
+ if ((data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
+ this->split_stack_adjust(symtab, pshdrs, sh_type, index,
+ prelocs, reloc_count, view, view_size,
+ &reloc_map);
+ }
+
if (!parameters->options().relocatable())
{
- target->relocate_section(&relinfo,
- sh_type,
- prelocs,
- reloc_count,
- os,
+ target->relocate_section(&relinfo, sh_type, prelocs, reloc_count, os,
output_offset == invalid_address,
- (*pviews)[index].view,
- (*pviews)[index].address,
- (*pviews)[index].view_size);
+ view, address, view_size, reloc_map);
if (parameters->options().emit_relocs())
this->emit_relocs(&relinfo, i, sh_type, prelocs, reloc_count,
- os, output_offset,
- (*pviews)[index].view,
- (*pviews)[index].address,
- (*pviews)[index].view_size,
- (*pviews)[i].view,
- (*pviews)[i].view_size);
+ os, output_offset, view, address, view_size,
+ (*pviews)[i].view, (*pviews)[i].view_size);
}
else
{
Relocatable_relocs* rr = this->relocatable_relocs(i);
- target->relocate_for_relocatable(&relinfo,
- sh_type,
- prelocs,
- reloc_count,
- os,
- output_offset,
- rr,
- (*pviews)[index].view,
- (*pviews)[index].address,
- (*pviews)[index].view_size,
+ target->relocate_for_relocatable(&relinfo, sh_type, prelocs,
+ reloc_count, os, output_offset, rr,
+ view, address, view_size,
(*pviews)[i].view,
(*pviews)[i].view_size);
}
}
}
+// If an object was compiled with -fsplit-stack, this is called to
+// check whether any relocations refer to functions defined in objects
+// which were not compiled with -fsplit-stack. If they were, then we
+// need to apply some target-specific adjustments to request
+// additional stack space.
+
+template<int size, bool big_endian>
+void
+Sized_relobj<size, big_endian>::split_stack_adjust(
+ const Symbol_table* symtab,
+ const unsigned char* pshdrs,
+ unsigned int sh_type,
+ unsigned int shndx,
+ const unsigned char* prelocs,
+ size_t reloc_count,
+ unsigned char* view,
+ section_size_type view_size,
+ Reloc_symbol_changes** reloc_map)
+{
+ if (sh_type == elfcpp::SHT_REL)
+ this->split_stack_adjust_reltype<elfcpp::SHT_REL>(symtab, pshdrs, shndx,
+ prelocs, reloc_count,
+ view, view_size,
+ reloc_map);
+ else
+ {
+ gold_assert(sh_type == elfcpp::SHT_RELA);
+ this->split_stack_adjust_reltype<elfcpp::SHT_RELA>(symtab, pshdrs, shndx,
+ prelocs, reloc_count,
+ view, view_size,
+ reloc_map);
+ }
+}
+
+// Adjust for -fsplit-stack, templatized on the type of the relocation
+// section.
+
+template<int size, bool big_endian>
+template<int sh_type>
+void
+Sized_relobj<size, big_endian>::split_stack_adjust_reltype(
+ const Symbol_table* symtab,
+ const unsigned char* pshdrs,
+ unsigned int shndx,
+ const unsigned char* prelocs,
+ size_t reloc_count,
+ unsigned char* view,
+ section_size_type view_size,
+ Reloc_symbol_changes** reloc_map)
+{
+ typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reltype;
+ const int reloc_size = Reloc_types<sh_type, size, big_endian>::reloc_size;
+
+ size_t local_count = this->local_symbol_count();
+
+ std::vector<section_offset_type> non_split_refs;
+
+ const unsigned char* pr = prelocs;
+ for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
+ {
+ Reltype reloc(pr);
+
+ typename elfcpp::Elf_types<size>::Elf_WXword r_info = reloc.get_r_info();
+ unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
+ if (r_sym < local_count)
+ continue;
+
+ const Symbol* gsym = this->global_symbol(r_sym);
+ gold_assert(gsym != NULL);
+ if (gsym->is_forwarder())
+ gsym = symtab->resolve_forwards(gsym);
+
+ // See if this relocation refers to a function defined in an
+ // object compiled without -fsplit-stack. Note that we don't
+ // care about the type of relocation--this means that in some
+ // cases we will ask for a large stack unnecessarily, but this
+ // is not fatal. FIXME: Some targets have symbols which are
+ // functions but are not type STT_FUNC, e.g., STT_ARM_TFUNC.
+ if (gsym->type() == elfcpp::STT_FUNC
+ && !gsym->is_undefined()
+ && gsym->source() == Symbol::FROM_OBJECT
+ && !gsym->object()->uses_split_stack())
+ {
+ section_offset_type offset =
+ convert_to_section_size_type(reloc.get_r_offset());
+ non_split_refs.push_back(offset);
+ }
+ }
+
+ if (non_split_refs.empty())
+ return;
+
+ // At this point, every entry in NON_SPLIT_REFS indicates a
+ // relocation which refers to a function in an object compiled
+ // without -fsplit-stack. We now have to convert that list into a
+ // set of offsets to functions. First, we find all the functions.
+
+ Function_offsets function_offsets;
+ this->find_functions(pshdrs, shndx, &function_offsets);
+ if (function_offsets.empty())
+ return;
+
+ // Now get a list of the function with references to non split-stack
+ // code.
+
+ Function_offsets calls_non_split;
+ for (std::vector<section_offset_type>::const_iterator p
+ = non_split_refs.begin();
+ p != non_split_refs.end();
+ ++p)
+ {
+ Function_offsets::const_iterator low = function_offsets.lower_bound(*p);
+ if (low == function_offsets.end())
+ --low;
+ else if (low->first == *p)
+ ;
+ else if (low == function_offsets.begin())
+ continue;
+ else
+ --low;
+
+ calls_non_split.insert(*low);
+ }
+ if (calls_non_split.empty())
+ return;
+
+ // Now we have a set of functions to adjust. The adjustments are
+ // target specific. Besides changing the output section view
+ // however, it likes, the target may request a relocation change
+ // from one global symbol name to another.
+
+ for (Function_offsets::const_iterator p = calls_non_split.begin();
+ p != calls_non_split.end();
+ ++p)
+ {
+ std::string from;
+ std::string to;
+ parameters->target().calls_non_split(this, shndx, p->first, p->second,
+ view, view_size, &from, &to);
+ if (!from.empty())
+ {
+ gold_assert(!to.empty());
+ Symbol* tosym = NULL;
+
+ // Find relocations in the relevant function which are for
+ // FROM.
+ pr = prelocs;
+ for (size_t i = 0; i < reloc_count; ++i, pr += reloc_size)
+ {
+ Reltype reloc(pr);
+
+ typename elfcpp::Elf_types<size>::Elf_WXword r_info =
+ reloc.get_r_info();
+ unsigned int r_sym = elfcpp::elf_r_sym<size>(r_info);
+ if (r_sym < local_count)
+ continue;
+
+ section_offset_type offset =
+ convert_to_section_size_type(reloc.get_r_offset());
+ if (offset < p->first
+ || (offset
+ >= (p->first
+ + static_cast<section_offset_type>(p->second))))
+ continue;
+
+ const Symbol* gsym = this->global_symbol(r_sym);
+ if (from == gsym->name())
+ {
+ if (tosym == NULL)
+ {
+ tosym = symtab->lookup(to.c_str());
+ if (tosym == NULL)
+ {
+ this->error(_("could not convert call "
+ "to '%s' to '%s'"),
+ from.c_str(), to.c_str());
+ break;
+ }
+ }
+
+ if (*reloc_map == NULL)
+ *reloc_map = new Reloc_symbol_changes(reloc_count);
+ (*reloc_map)->set(i, tosym);
+ }
+ }
+ }
+ }
+}
+
+// Find all the function in this object defined in section SHNDX.
+// Store their offsets in the section in FUNCTION_OFFSETS.
+
+template<int size, bool big_endian>
+void
+Sized_relobj<size, big_endian>::find_functions(
+ const unsigned char* pshdrs,
+ unsigned int shndx,
+ Sized_relobj<size, big_endian>::Function_offsets* function_offsets)
+{
+ // We need to read the symbols to find the functions. If we wanted
+ // to, we could cache reading the symbols across all sections in the
+ // object.
+ const unsigned int symtab_shndx = this->symtab_shndx_;
+ typename This::Shdr symtabshdr(pshdrs + symtab_shndx * This::shdr_size);
+ gold_assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
+
+ typename elfcpp::Elf_types<size>::Elf_WXword sh_size =
+ symtabshdr.get_sh_size();
+ const unsigned char* psyms = this->get_view(symtabshdr.get_sh_offset(),
+ sh_size, true, true);
+
+ const int sym_size = This::sym_size;
+ const unsigned int symcount = sh_size / sym_size;
+ for (unsigned int i = 0; i < symcount; ++i, psyms += sym_size)
+ {
+ typename elfcpp::Sym<size, big_endian> isym(psyms);
+
+ // FIXME: Some targets can have functions which do not have type
+ // STT_FUNC, e.g., STT_ARM_TFUNC.
+ if (isym.get_st_type() != elfcpp::STT_FUNC
+ || isym.get_st_size() == 0)
+ continue;
+
+ bool is_ordinary;
+ unsigned int sym_shndx = this->adjust_sym_shndx(i, isym.get_st_shndx(),
+ &is_ordinary);
+ if (!is_ordinary || sym_shndx != shndx)
+ continue;
+
+ section_offset_type value =
+ convert_to_section_size_type(isym.get_st_value());
+ section_size_type fnsize =
+ convert_to_section_size_type(isym.get_st_size());
+
+ (*function_offsets)[value] = fnsize;
+ }
+}
+
// Class Merged_symbol_value.
template<int size>
Sized_relobj<64, true>::do_read_relocs(Read_relocs_data* rd);
#endif
+#ifdef HAVE_TARGET_32_LITTLE
+template
+void
+Sized_relobj<32, false>::do_gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Read_relocs_data* rd);
+#endif
+
+#ifdef HAVE_TARGET_32_BIG
+template
+void
+Sized_relobj<32, true>::do_gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Read_relocs_data* rd);
+#endif
+
+#ifdef HAVE_TARGET_64_LITTLE
+template
+void
+Sized_relobj<64, false>::do_gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Read_relocs_data* rd);
+#endif
+
+#ifdef HAVE_TARGET_64_BIG
+template
+void
+Sized_relobj<64, true>::do_gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Read_relocs_data* rd);
+#endif
+
#ifdef HAVE_TARGET_32_LITTLE
template
void