Add support for creating shared libraries under i386 ELF and SPARC

	ELF.  Based on patches by Eric Youngdale <ericy@cais.cais.com>.
	* libelf.h (struct elf_link_hash_entry): Remove copy_offset field.
	Add got_offset and plt_offset fields.
	(ELF_LINK_HASH_REF_DYNAMIC_MULTIPLE): Don't define.
	(ELF_LINK_HASH_DEF_DYNAMIC_MULTIPLE): Don't define.
	(ELF_LINK_HASH_NEEDS_COPY): Define.
	(struct elf_backend_data): Add check_relocs field.
	(struct bfd_elf_section_data): Change relocs from PTR to
	Elf_Internal_Rela *.
	(struct elf_obj_tdata): Add local_got_offsets field.
	(elf_local_got_offsets): Define accessor macro.
	(bfd_elf32_link_create_dynamic_sections): Declare.
	(bfd_elf32_link_record_dynamic_symbol): Declare.
	(bfd_elf64_link_create_dynamic_sections): Declare.
	(bfd_elf64_link_record_dynamic_symbol): Declare.
	* elfcode.h (elf_slurp_reloc_table): Don't use the section data
	relocs field.
	(elf_link_record_dynamic_symbol): Make globally visible.  Use
	macro to rename to NAME(bfd_elf,link_record_dynamic_symbol).
	(elf_link_add_object_symbols): If creating a shared library, put
	make all local symbols dynamic.  Don't bother with the
	DYNAMIC_MULTIPLE flags.  Call the check_relocs backend function if
	it is defined.
	(elf_link_create_dynamic_sections): Make globally visible.  Use
	macro to rename to NAME(bfd_elf,link_create_dynamic_sections).  If
	creating a shared library, make sure that _DYNAMIC is added as a
	dynamic symbol.
	(elf_link_read_relocs): New function.
	(NAME(bfd_elf,record_link_assignment)): If creating a shared
	library, always create symbols, and always make them dynamic.
	(elf_bfd_final_link): Permit creation of shared libraries.
	(elf_link_input_bfd): Use elf_link_read_relocs to get the relocs.
	* elf.c (_bfd_elf_link_hash_newfunc): Don't initialize
	copy_offset.  Initialize got_offset and plt_offset.
	* elf32-target.h (elf_backend_check_relocs): Define as 0 if not
	defined.
	(elf32_bed): Initialize check_relocs field.
	* elf64-target.h (elf_backend_check_relocs): Define as 0 if not
	defined.
	(elf64_bed): Initialize check_relocs field.
	* elf32-i386.c (elf_howto_table): Change R_386_PLT32 and
	R_386_GOTPC to be pc_relative and pcrel_offset.
	(elf_i386_pic_plt0_entry): Define.
	(elf_i386_pic_plt_entry): Define.
	(elf_i386_create_dynamic_sections): Create a .got.plt section, and
	define _GLOBAL_OFFSET_TABLE_ at the start of it.  If creating a
	shared library, make sure that _GLOBAL_OFFSET_TABLE_ is added as a
	dynamic symbol.  Don't create .rel.bss if creating a shared
	library.
	(elf_i386_check_relocs): New function.
	(elf_i386_adjust_dynamic_symbol): Don't make a PLT entry if the
	symbol already has one.  When making a PLT entry, set plt_offset.
	Don't create a copy reloc when creating a shared library.  Don't
	set copy_offset, just set ELF_LINK_HASH_NEEDS_COPY.
	(elf_i386_allocate_dynamic_section): Remove.
	(elf_i386_size_dynamic_sections): Look through all the sections
	rather than assuming we know their names.  Remove any empty reloc
	or plt sections.  Only add a DT_DEBUG entry if not creating a
	shared library.  Only add a DT_PLTGOT entry if there is a PLT.
	Add a DT_TEXTREL entry if required.
	(elf_i386_relocate_section): Permit undefined symbols when
	creating a shared library.  Handle the special relocation types
	specially.
	(elf_i386_finish_dynamic_symbol): Create a PLT entry if plt_offset
	is set.  If creating a shared library, produce a PIC PLT entry.
	Only mark a PLT symbol as undefined if it was not defined by a
	regular object file.  Create a GOT entry if got_offset is set.
	Create a copy reloc if ELF_LINK_HASH_NEEDS_COPY is set.
	(elf_i386_finish_dynamic_sections): Change the handling of
	DT_RELSZ to simply subtract out the size of .rel.plt.  If creating
	a shared library, produce PIC PLT code.
	(elf_backend_check_relocs): Define.
	* elf32-sparc.c (elf_sparc_howto_table): Change R_SPARC_GOT10,
	R_SPARC_GOT22, and R_SPARC_PC10 to not warn about reloc overflow.
	(elf32_sparc_create_dynamic_sections): If creating a shared
	library, make sure that _GLOBAL_OFFSET_TABLE_ is added as a
        dynamic symbol, and set the type to STT_OBJECT.  Likewise for
        _PROCEDURE_LINKAGE_TABLE_.  Don't create .rel.bss if creating a
        shared library.
	(elf32_sparc_check_relocs): New function.
	(elf32_sparc_adjust_dynamic_symbol): Don't make a PLT entry if the
	symbol already has one.  When making a PLT entry, set plt_offset.
	Don't create a copy reloc when creating a shared library.  Don't
	set copy_offset, just set ELF_LINK_HASH_NEEDS_COPY.
	(elf32_sparc_allocate_dynamic_section): Remove.
	(elf32_sparc_size_dynamic_sections): Look through all the sections
	rather than assuming we know their names.  Only add a DT_DEBUG
	entry if not creating a shared library.  Add a DT_TEXTREL entry if
	required.
	(elf32_sparc_relocate_section): Permit undefined symbols when
	creating a shared library.  Handle the special relocation types
	specially.
	(elf32_sparc_finish_dynamic_symbol): Create a PLT entry if plt_offset
	is set.  Only mark a PLT symbol as undefined if it was not defined
	by a regular object file.  Create a GOT entry if got_offset is
	set.  Create a copy reloc if ELF_LINK_HASH_NEEDS_COPY is set.
	(elf32_sparc_finish_dynamic_sections): Store dynobj in a local
	variable.
	(elf_backend_check_relocs): Define.

1 files changed, 47 insertions, 11 deletions

diff --git a/bfd/libelf.h b/bfd/libelf.h
index f14ac95..d43f135 100644
--- a/bfd/libelf.h
+++ b/bfd/libelf.h
@@ -89,9 +89,18 @@ struct elf_link_hash_entry
      one.  Otherwise it is NULL.  */
   struct elf_link_hash_entry *weakdef;
 
-  /* If we need to generate a COPY reloc, the processor specific
-     backend uses this to hold the offset into the reloc section.  */
-  bfd_vma copy_offset;
+  /* If this symbol requires an entry in the global offset table, the
+     processor specific backend uses this field to hold the offset
+     into the .got section.  If this field is -1, then the symbol does
+     not require a global offset table entry.  */
+  bfd_vma got_offset;
+
+  /* If this symbol requires an entry in the procedure linkage table,
+     the processor specific backend uses these two fields to hold the
+     offset into the procedure linkage section and the offset into the
+     .got section.  If plt_offset is -1, then the symbol does not
+     require an entry in the procedure linkage table.  */
+  bfd_vma plt_offset;
 
   /* Symbol type (STT_NOTYPE, STT_OBJECT, etc.).  */
   char type;
@@ -106,14 +115,12 @@ struct elf_link_hash_entry
 #define ELF_LINK_HASH_REF_DYNAMIC 04
   /* Symbol is defined by a shared object.  */
 #define ELF_LINK_HASH_DEF_DYNAMIC 010
-  /* Symbol is referenced by two or more shared objects.  */
-#define ELF_LINK_HASH_REF_DYNAMIC_MULTIPLE 020
-  /* Symbol is defined by two or more shared objects.  */
-#define ELF_LINK_HASH_DEF_DYNAMIC_MULTIPLE 040
   /* Dynamic symbol has been adjustd.  */
-#define ELF_LINK_HASH_DYNAMIC_ADJUSTED 0100
+#define ELF_LINK_HASH_DYNAMIC_ADJUSTED 020
   /* Symbol is defined as weak.  */
-#define ELF_LINK_HASH_DEFINED_WEAK 0200
+#define ELF_LINK_HASH_DEFINED_WEAK 040
+  /* Symbol needs a copy reloc.  */
+#define ELF_LINK_HASH_NEEDS_COPY 0100
 };
 
 /* ELF linker hash table.  */
@@ -277,6 +284,20 @@ struct elf_backend_data
   boolean (*elf_backend_create_dynamic_sections)
     PARAMS ((bfd *abfd, struct bfd_link_info *info));
 
+  /* The CHECK_RELOCS function is called by the add_symbols phase of
+     the ELF backend linker.  It is called once for each section with
+     relocs of an object file, just after the symbols for the object
+     file have been added to the global linker hash table.  The
+     function must look through the relocs and do any special handling
+     required.  This generally means allocating space in the global
+     offset table, and perhaps allocating space for a reloc.  The
+     relocs are always passed as Rela structures; if the section
+     actually uses Rel structures, the r_addend field will always be
+     zero.  */
+  boolean (*check_relocs)
+    PARAMS ((bfd *abfd, struct bfd_link_info *info, asection *o,
+	     const Elf_Internal_Rela *relocs));
+
   /* The ADJUST_DYNAMIC_SYMBOL function is called by the ELF backend
      linker for every symbol which is defined by a dynamic object and
      referenced by a regular object.  This is called after all the
@@ -396,8 +417,10 @@ struct bfd_elf_section_data {
   /* Used by the backend linker to store the symbol hash table entries
      associated with relocs against global symbols.  */
   struct elf_link_hash_entry **rel_hashes;
-  /* A pointer to the unswapped external relocs; this may be NULL.  */
-  PTR relocs;
+  /* A pointer to the swapped relocs.  If the section uses REL relocs,
+     rather than RELA, all the r_addend fields will be zero.  This
+     pointer may be NULL.  It is used by the backend linker.  */
+  Elf_Internal_Rela *relocs;
 };
 
 #define elf_section_data(sec)  ((struct bfd_elf_section_data*)sec->used_by_bfd)
@@ -443,6 +466,10 @@ struct elf_obj_tdata
      minus the sh_info field of the symbol table header.  */
   struct elf_link_hash_entry **sym_hashes;
 
+  /* A mapping from local symbols to offsets into the global offset
+     table, used when linking.  This is indexed by the symbol index.  */
+  bfd_vma *local_got_offsets;
+
   /* The linker ELF emulation code needs to let the backend ELF linker
      know what filename should be used for a dynamic object if the
      dynamic object is found using a search.  This field is used to
@@ -473,6 +500,7 @@ struct elf_obj_tdata
 #define elf_gp(bfd)		(elf_tdata(bfd) -> gp)
 #define elf_gp_size(bfd)	(elf_tdata(bfd) -> gp_size)
 #define elf_sym_hashes(bfd)	(elf_tdata(bfd) -> sym_hashes)
+#define elf_local_got_offsets(bfd) (elf_tdata(bfd) -> local_got_offsets)
 #define elf_dt_needed_name(bfd)	(elf_tdata(bfd) -> dt_needed_name)
 #define elf_bad_symtab(bfd)	(elf_tdata(bfd) -> bad_symtab)
 
@@ -565,6 +593,10 @@ extern void bfd_elf32_swap_dyn_out
   PARAMS ((bfd *, const Elf_Internal_Dyn *, Elf32_External_Dyn *));
 extern boolean bfd_elf32_add_dynamic_entry
   PARAMS ((struct bfd_link_info *, bfd_vma, bfd_vma));
+extern boolean bfd_elf32_link_create_dynamic_sections
+  PARAMS ((bfd *, struct bfd_link_info *));
+extern boolean bfd_elf32_link_record_dynamic_symbol
+  PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *));
 
 /* If the target doesn't have reloc handling written yet:  */
 extern void bfd_elf32_no_info_to_howto PARAMS ((bfd *, arelent *,
@@ -626,6 +658,10 @@ extern void bfd_elf64_swap_dyn_out
   PARAMS ((bfd *, const Elf_Internal_Dyn *, Elf64_External_Dyn *));
 extern boolean bfd_elf64_add_dynamic_entry
   PARAMS ((struct bfd_link_info *, bfd_vma, bfd_vma));
+extern boolean bfd_elf64_link_create_dynamic_sections
+  PARAMS ((bfd *, struct bfd_link_info *));
+extern boolean bfd_elf64_link_record_dynamic_symbol
+  PARAMS ((struct bfd_link_info *, struct elf_link_hash_entry *));
 
 /* If the target doesn't have reloc handling written yet:  */
 extern void bfd_elf64_no_info_to_howto PARAMS ((bfd *, arelent *,