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author | Ian Lance Taylor <ian@airs.com> | 2008-04-16 22:54:29 +0000 |
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committer | Ian Lance Taylor <ian@airs.com> | 2008-04-16 22:54:29 +0000 |
commit | 12c0daef5f792cf27f8d0897794bb32729dc370b (patch) | |
tree | a282dbfb5ea5b87e31cd1eb4e61bf04584bcd9f7 /gold/copy-relocs.cc | |
parent | 4f4995b6282c41516d0bd895832ced99d799a744 (diff) | |
download | gdb-12c0daef5f792cf27f8d0897794bb32729dc370b.zip gdb-12c0daef5f792cf27f8d0897794bb32729dc370b.tar.gz gdb-12c0daef5f792cf27f8d0897794bb32729dc370b.tar.bz2 |
* copy-relocs.cc: New file.
* copy-relocs.h: New file.
* reloc.cc: Remove Copy_relocs code.
* reloc.h: Likewise.
* reloc-types.h (struct Reloc_types) [both versions]: Add
get_reloc_addend_noerror.
* output.h (class Output_data_reloc<elfcpp::SHT_REL>): Add
variants of add_global which take an addend which must be zero.
* i386.cc: Include "copy-relocs.h".
(class Target_i386): Change type of copy_relocs_ to variable,
update initializer.
(Target_i386::copy_reloc): Rewrite to pass to Copy_relocs class.
Change all callers.
(Target_i386::do_finalize_sections): Change handling of
copy_relocs_.
* sparc.cc: Include "copy-relocs.h".
(class Target_sparc): Change type of copy_relocs_ to variable,
update initializer.
(Target_sparc::copy_reloc): Rewrite to pass to Copy_relocs class.
Change all callers.
(Target_sparc::do_finalize_sections): Change handling of
copy_relocs_.
* x86_64.cc: Include "copy-relocs.h".
(class Target_x86_64): Change type of copy_relocs_ to variable,
update initializer.
(Target_x86_64::copy_reloc): Rewrite to pass to Copy_relocs
class. Change all callers.
(Target_x86_64::do_finalize_sections): Change handling of
copy_relocs_.
* Makefile.am (CCFILES): Add copy-relocs.cc.
(HFILES): Add copy-relocs.h.
Diffstat (limited to 'gold/copy-relocs.cc')
-rw-r--r-- | gold/copy-relocs.cc | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/gold/copy-relocs.cc b/gold/copy-relocs.cc new file mode 100644 index 0000000..1e9705e --- /dev/null +++ b/gold/copy-relocs.cc @@ -0,0 +1,235 @@ +// copy-relocs.cc -- handle COPY relocations for gold. + +// Copyright 2006, 2007, 2008 Free Software Foundation, Inc. +// Written by Ian Lance Taylor <iant@google.com>. + +// This file is part of gold. + +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 3 of the License, or +// (at your option) any later version. + +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, +// MA 02110-1301, USA. + +#include "gold.h" + +#include "symtab.h" +#include "copy-relocs.h" + +namespace gold +{ + +// Copy_relocs::Copy_reloc_entry methods. + +// Emit the reloc if appropriate. + +template<int sh_type, int size, bool big_endian> +void +Copy_relocs<sh_type, size, big_endian>::Copy_reloc_entry::emit( + Output_data_reloc<sh_type, true, size, big_endian>* reloc_section) +{ + // If the symbol is no longer defined in a dynamic object, then we + // emitted a COPY relocation, and we do not want to emit this + // dynamic relocation. + if (this->sym_->is_from_dynobj()) + reloc_section->add_global(this->sym_, this->reloc_type_, + this->output_section_, this->relobj_, + this->shndx_, this->address_, + this->addend_); +} + +// Copy_relocs methods. + +// Handle a relocation against a symbol which may force us to generate +// a COPY reloc. + +template<int sh_type, int size, bool big_endian> +void +Copy_relocs<sh_type, size, big_endian>::copy_reloc( + Symbol_table* symtab, + Layout* layout, + Sized_symbol<size>* sym, + Relobj* object, + unsigned int shndx, + Output_section *output_section, + const Reloc& rel, + Output_data_reloc<sh_type, true, size, big_endian>* reloc_section) +{ + if (this->need_copy_reloc(sym, object, shndx)) + this->emit_copy_reloc(symtab, layout, sym, reloc_section); + else + { + // We may not need a COPY relocation. Save this relocation to + // possibly be emitted later. + this->save(sym, object, shndx, output_section, rel); + } +} + +// Return whether we need a COPY reloc for a relocation against SYM. +// The relocation is begin applied to section SHNDX in OBJECT. + +template<int sh_type, int size, bool big_endian> +bool +Copy_relocs<sh_type, size, big_endian>::need_copy_reloc( + Sized_symbol<size>* sym, + Relobj* object, + unsigned int shndx) const +{ + // FIXME: Handle -z nocopyrelocs. + + if (sym->symsize() == 0) + return false; + + // If this is a readonly section, then we need a COPY reloc. + // Otherwise we can use a dynamic reloc. Note that calling + // section_flags here can be slow, as the information is not cached; + // fortunately we shouldn't see too many potential COPY relocs. + if ((object->section_flags(shndx) & elfcpp::SHF_WRITE) == 0) + return true; + + return false; +} + +// Emit a COPY relocation for SYM. + +template<int sh_type, int size, bool big_endian> +void +Copy_relocs<sh_type, size, big_endian>::emit_copy_reloc( + Symbol_table* symtab, + Layout* layout, + Sized_symbol<size>* sym, + Output_data_reloc<sh_type, true, size, big_endian>* reloc_section) +{ + typename elfcpp::Elf_types<size>::Elf_WXword symsize = sym->symsize(); + + // There is no defined way to determine the required alignment of + // the symbol. We know that the symbol is defined in a dynamic + // object. We start with the alignment of the section in which it + // is defined; presumably we do not require an alignment larger than + // that. Then we reduce that alignment if the symbol is not aligned + // within the section. + gold_assert(sym->is_from_dynobj()); + typename elfcpp::Elf_types<size>::Elf_WXword addralign = + sym->object()->section_addralign(sym->shndx()); + + typename Sized_symbol<size>::Value_type value = sym->value(); + while ((value & (addralign - 1)) != 0) + addralign >>= 1; + + if (this->dynbss_ == NULL) + { + this->dynbss_ = new Output_data_space(addralign); + layout->add_output_section_data(".bss", + elfcpp::SHT_NOBITS, + elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, + this->dynbss_); + } + + Output_data_space* dynbss = this->dynbss_; + + if (addralign > dynbss->addralign()) + dynbss->set_space_alignment(addralign); + + section_size_type dynbss_size = + convert_to_section_size_type(dynbss->current_data_size()); + dynbss_size = align_address(dynbss_size, addralign); + section_size_type offset = dynbss_size; + dynbss->set_current_data_size(dynbss_size + symsize); + + // Define the symbol as being copied. + symtab->define_with_copy_reloc(sym, dynbss, offset); + + // Add the COPY relocation to the dynamic reloc section. + this->add_copy_reloc(sym, offset, reloc_section); +} + +// Add a COPY relocation for SYM to RELOC_SECTION. + +template<int sh_type, int size, bool big_endian> +void +Copy_relocs<sh_type, size, big_endian>::add_copy_reloc( + Symbol* sym, + section_size_type offset, + Output_data_reloc<sh_type, true, size, big_endian>* reloc_section) +{ + reloc_section->add_global(sym, this->copy_reloc_type_, this->dynbss_, + offset, 0); +} + +// Save a relocation to possibly be emitted later. + +template<int sh_type, int size, bool big_endian> +void +Copy_relocs<sh_type, size, big_endian>::save(Symbol* sym, Relobj* object, + unsigned int shndx, + Output_section* output_section, + const Reloc& rel) +{ + unsigned int reloc_type = elfcpp::elf_r_type<size>(rel.get_r_info()); + typename elfcpp::Elf_types<size>::Elf_Addr addend = + Reloc_types<sh_type, size, big_endian>::get_reloc_addend_noerror(&rel); + this->entries_.push_back(Copy_reloc_entry(sym, reloc_type, object, shndx, + output_section, rel.get_r_offset(), + addend)); +} + +// Emit any saved relocs. + +template<int sh_type, int size, bool big_endian> +void +Copy_relocs<sh_type, size, big_endian>::emit( + Output_data_reloc<sh_type, true, size, big_endian>* reloc_section) +{ + for (typename Copy_reloc_entries::iterator p = this->entries_.begin(); + p != this->entries_.end(); + ++p) + p->emit(reloc_section); + + // We no longer need the saved information. + this->entries_.clear(); +} + +// Instantiate the templates we need. + +#ifdef HAVE_TARGET_32_LITTLE +template +class Copy_relocs<elfcpp::SHT_REL, 32, false>; + +template +class Copy_relocs<elfcpp::SHT_RELA, 32, false>; +#endif + +#ifdef HAVE_TARGET_32_BIG +template +class Copy_relocs<elfcpp::SHT_REL, 32, true>; + +template +class Copy_relocs<elfcpp::SHT_RELA, 32, true>; +#endif + +#ifdef HAVE_TARGET_64_LITTLE +template +class Copy_relocs<elfcpp::SHT_REL, 64, false>; + +template +class Copy_relocs<elfcpp::SHT_RELA, 64, false>; +#endif + +#ifdef HAVE_TARGET_64_BIG +template +class Copy_relocs<elfcpp::SHT_REL, 64, true>; + +template +class Copy_relocs<elfcpp::SHT_RELA, 64, true>; +#endif + +} // End namespace gold. |