* 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.

gold/copy-relocs.h

@@ -0,0 +1,152 @@
+// copy-relocs.h -- handle COPY relocations for gold   -*- C++ -*-
+
+// 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.
+
+#ifndef GOLD_COPY_RELOCS_H
+#define GOLD_COPY_RELOCS_H
+
+#include "elfcpp.h"
+#include "reloc-types.h"
+#include "output.h"
+
+namespace gold
+{
+
+// This class is used to manage COPY relocations.  We try to avoid
+// them when possible.  A COPY relocation may be required when an
+// executable refers to a variable defined in a shared library.  COPY
+// relocations are problematic because they tie the executable to the
+// exact size of the variable in the shared library.  We can avoid
+// them if all the references to the variable are in a writeable
+// section.  In that case we can simply use dynamic relocations.
+// However, when scanning relocs, we don't know when we see the
+// relocation whether we will be forced to use a COPY relocation or
+// not.  So we have to save the relocation during the reloc scanning,
+// and then emit it as a dynamic relocation if necessary.  This class
+// implements that.  It is used by the target specific code.
+
+// The template parameter SH_TYPE is the type of the reloc section to
+// be used for COPY relocs: elfcpp::SHT_REL or elfcpp::SHT_RELA.
+
+template<int sh_type, int size, bool big_endian>
+class Copy_relocs
+{
+ private:
+  typedef typename Reloc_types<sh_type, size, big_endian>::Reloc Reloc;
+
+ public:
+  Copy_relocs(unsigned int copy_reloc_type)
+    : copy_reloc_type_(copy_reloc_type), dynbss_(NULL), entries_()
+  { }
+
+  // This is called while scanning relocs if we see a relocation
+  // against a symbol which may force us to generate a COPY reloc.
+  // SYM is the symbol.  OBJECT is the object whose relocs we are
+  // scanning.  The relocation is being applied to section SHNDX in
+  // OBJECT.  OUTPUT_SECTION is the output section where section SHNDX
+  // will wind up.  REL is the reloc itself.  The Output_data_reloc
+  // section is where the dynamic relocs are put.
+  void
+  copy_reloc(Symbol_table*, 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>*);
+
+  // Return whether there are any saved relocations.
+  bool
+  any_saved_relocs() const
+  { return !this->entries_.empty(); }
+
+  // Emit any saved relocations which turn out to be needed.  This is
+  // called after all the relocs have been scanned.
+  void
+  emit(Output_data_reloc<sh_type, true, size, big_endian>*);
+
+ private:
+  typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
+  typedef typename elfcpp::Elf_types<size>::Elf_Addr Addend;
+
+  // This POD class holds the relocations we are saving.  We will emit
+  // these relocations if it turns out that the symbol does not
+  // require a COPY relocation.
+  class Copy_reloc_entry
+  {
+   public:
+    Copy_reloc_entry(Symbol* sym, unsigned int reloc_type,
+		     Relobj* relobj, unsigned int shndx,
+		     Output_section* output_section,
+		     Address address, Addend addend)
+      : sym_(sym), reloc_type_(reloc_type), relobj_(relobj),
+	shndx_(shndx), output_section_(output_section),
+	address_(address), addend_(addend)
+    { }
+
+    // Emit this reloc if appropriate.  This is called after we have
+    // scanned all the relocations, so we know whether we emitted a
+    // COPY relocation for SYM_.
+    void
+    emit(Output_data_reloc<sh_type, true, size, big_endian>*);
+
+   private:
+    Symbol* sym_;
+    unsigned int reloc_type_;
+    Relobj* relobj_;
+    unsigned int shndx_;
+    Output_section* output_section_;
+    Address address_;
+    Addend addend_;
+  };
+
+  // A list of relocs to be saved.
+  typedef std::vector<Copy_reloc_entry> Copy_reloc_entries;
+
+  // Return whether we need a COPY reloc.
+  bool
+  need_copy_reloc(Sized_symbol<size>* gsym, Relobj* object,
+		  unsigned int shndx) const;
+
+  // Emit a COPY reloc.
+  void
+  emit_copy_reloc(Symbol_table*, Layout*, Sized_symbol<size>*,
+		  Output_data_reloc<sh_type, true, size, big_endian>*);
+
+  // Add a COPY reloc to the dynamic reloc section.
+  void
+  add_copy_reloc(Symbol*, section_size_type,
+		 Output_data_reloc<sh_type, true, size, big_endian>*);
+
+  // Save a reloc against SYM for possible emission later.
+  void
+  save(Symbol*, Relobj*, unsigned int shndx, Output_section*,
+       const Reloc& rel);
+
+  // The target specific relocation type of the COPY relocation.
+  const unsigned int copy_reloc_type_;
+  // The dynamic BSS data which goes into the .bss section.  This is
+  // where variables which require COPY relocations are placed.
+  Output_data_space* dynbss_;
+  // The list of relocs we are saving.
+  Copy_reloc_entries entries_;
+};
+
+} // End namespace gold.
+
+#endif // !defined(GOLD_COPY_RELOCS_H)