Compact EH Support

The specification for the Compact EH format is available at:
https://github.com/MentorEmbedded/cxx-abi/blob/master/MIPSCompactEH.pdf

2015-05-28  Catherine Moore  <clm@codesourcery.com>
	    Bernd Schmidt <bernds@codesourcery.com>
	    Paul Brook <paul@codesourcery.com>

	bfd/
	* bfd-in2.h: Regenerated.
	* elf-bfd.h (DWARF2_EH_HDR, COMPACT_EH_HDR): Define.
	(COMPACT_EH_CANT_UNWIND_OPCODE): Define.
	(dwarf_eh_frame_hdr_info): Move dwarf-specific fields from
	eh_frame_hdr_info.
	(compact_eh_frame_hdr_info): Declare.
	(eh_frame_hdr_info):  Redeclare with union for dwarf-specific
	fields and compact-eh fields.
	(elf_backend_data): Add cant_unwind_opcode and compact_eh_encoding.
	(bfd_elf_section_data): Add eh_frame_entry_field.
	(elf_section_eh_frame_entry): Define.
	(bfd_elf_parse_eh_frame_entries): Declare.
	(_bfd_elf_parse_eh_frame_entry): Declare.
	(_bfd_elf_end_eh_frame_parsing): Declare.
	(_bfd_elf_write_section_eh_frame_entry): Declare.
	(_bfd_elf_eh_frame_entry_present): Declare.
	(_bfd_elf_section_for_symbol): Declare.
	* elf-eh-frame.c (bfd_elf_discard_eh_frame_entry): New function.
	(bfd_elf_record_eh_frame_entry): New function.
	(_bfd_elf_parse_eh_frame_entry): New function.
	(_bfd_elf_parse_eh_frame): Update hdr_info field references.
	(cmp_eh_frame_hdr): New function.
	(add_eh_frame_hdr_terminator): New function.
	(_bfd_elf_end_eh_frame_parsing): New function.
	(find_merged_cie): Update hdr_info field references.
	(_bfd_elf_discard_section_eh_frame): Likewise.
	(_bfd_elf_discard_section_eh_frame_hdr): Add Compact EH support.
	(_bfd_elf_eh_frame_entry_present): New function.
	(_bfd_elf_maybe_strip_eh_frame_hdr): Add Compact EH support.
	(_bfd_elf_write_section_eh_frame_entry): New function.
	(_bfd_elf_write_section_eh_frame): Update hdr_info field references.
	(_bfd_elf_fixup_eh_frame_hdr): New function.
	(write_compact_eh_frame_hdr): New function.
	(write_dwarf_eh_frame_hdr): New function.
	(_bfd_elf_write_section_eh_frame_hdr): Add Compact EH support.
	* elflink.c (_bfd_elf_section_for_symbol): New function.
	(elf_section_ignore_discarded_relocs): Add Compact EH support.
	(elf_link_input_bfd): Likewise.
	(bfd_elf_final_link): Likewise.
	(_bfd_elf_gc_mark): Likewise.
	(bfd_elf_parse_eh_frame_entries): New function.
	(bfd_elf_gc_sections): Add Compact EH support.
	(bfd_elf_discard_info): Likewise.
	* elfxx-mips.c: Include dwarf2.h.
	(_bfd_mips_elf_compact_eh_encoding): New function.
	(_bfd_mips_elf_cant_unwind_opcode): New function.
	* elfxx-mips.h (_bfd_mips_elf_compact_eh_encoding): Declare.
	(_bfd_mips_elf_cant_unwind_opcode): Declare.
	(elf_backend_compact_eh_encoding): Define.
	(elf_backend_cant_unwind_opcode): Define.
	* elfxx-target.h (elf_backend_compact_eh_encoding): Provide default.
	(elf_backend_cant_unwind_opcode): Provide default.
	(elf_backend_data elfNN_bed): Add elf_backend_compact_eh_encoding and
	elf_backend_cant_unwind_opcode.
	* section.c (SEC_INFO_TYPE_EH_FRAME_ENTRY): Add definition.

	gas/
	* config/tc-alpha.c (all_cfi_sections): Declare.
	(s_alpha_ent): Initialize all_cfi_sections.
	(alpha_elf_md_end): Invoke cfi_set_sections.
	* config/tc-mips.c (md_apply_fix):  Handle BFD_RELOC_NONE.
	(s_ehword): Use BFD_RELOC_32_PCREL.
	(mips_fix_adjustable): Handle BFD_RELOC_32_PCREL.
	(mips_cfi_reloc_for_encoding): New function.
	* tc-mips.h (DWARF2_FDE_RELOC_SIZE): Redefine.
	(DWARF2_FDE_RELOC_ENCODING): Define.
	(tc_cfi_reloc_for_encoding): Define.
	(mips_cfi_reloc_for_encoding): Define.
	(tc_compact_eh_opcode_stop): Define.
	(tc_compact_eh_opcode_pad): Define.
	* doc/as.texinfo: Document Compact EH extensions.
	* doc/internals.texi: Likewise.
	* dw2gencfi.c (EH_FRAME_LINKONCE): Redefine.
	(tc_cfi_reloc_for_encoding): Provide default.
	(compact_eh): Declare.
	(emit_expr_encoded): New function.
	(get_debugseg_name): Add Compact EH support.
	(alloc_debugseg_item): Likewise.
	(cfi_set_sections): New function.
	(dot_cfi_fde_data): New function.
	(dot_cfi_personality_id): New function.
	(dot_cfi_inline_lsda): New function.
	(cfi_pseudo_table): Add cfi_fde_data, cfi_personality_id,
	and cfi_inline_lsda.
	(dot_cfi_personality): Add Compact EH support.
	(dot_cfi_lsda): Likewise.
	(dot_cfi_sections): Likewise.
	(dot_cfi_startproc): Likewise.
	(get_cfi_seg): Likewise.
	(output_compact_unwind_data): New function.
	(output_cfi_insn): Add Compact EH support.
	(output_cie): Likewise.
	(output_fde): Likewise.
	(cfi_finish): Likewise.
	(cfi_emit_eh_header): New function.
	(output_eh_header): New function.
	* dw2gencfi.h (cfi_set_sections): Declare.
	(SUPPORT_COMPACT_EH): Define.
	(MULTIPLE_FRAME_SECTIONS): Define.
	New enumeration to describe the Compact EH header format.
	(fde_entry): Add new fields personality_id, eh_header_type, eh_data_size,
	eh_data, eh_loc and sections.
	(CFI_EMIT_eh_frame, CFI_EMIT_debug_frame, CFI_EMIT_target,
	CFI_EMIT_eh_frame_compact): Define.

2015-05-22  Catherine Moore  <clm@codesourcery.com>
	    Bernd Schmidt <bernds@codesourcery.com>

	gas/testsuite/
	* gas/mips/mips.exp: Run new tests.

	* gas/mips/compact-eh-1.s: New file.
	* gas/mips/compact-eh-2.s: New file.
	* gas/mips/compact-eh-3.s: New file.
	* gas/mips/compact-eh-4.s: New file.
	* gas/mips/compact-eh-5.s: New file.
	* gas/mips/compact-eh-6.s: New file.
	* gas/mips/compact-eh-7.s: New file.
	* gas/mips/compact-eh-eb-1.d: New file.
	* gas/mips/compact-eh-eb-2.d: New file.
	* gas/mips/compact-eh-eb-3.d: New file.
	* gas/mips/compact-eh-eb-4.d: New file.
	* gas/mips/compact-eh-eb-5.d: New file.
	* gas/mips/compact-eh-eb-6.d: New file.
	* gas/mips/compact-eh-eb-7.d: New file.
	* gas/mips/compact-eh-el-1.d: New file.
	* gas/mips/compact-eh-el-2.d: New file.
	* gas/mips/compact-eh-el-3.d: New file.
	* gas/mips/compact-eh-el-4.d: New file.
	* gas/mips/compact-eh-el-5.d: New file.
	* gas/mips/compact-eh-el-6.d: New file.
	* gas/mips/compact-eh-el-7.d: New file.
	* gas/mips/compact-eh-err1.l: New file.
	* gas/mips/compact-eh-err1.s: New file.
	* gas/mips/compact-eh-err2.l: New file.
	* gas/mips/compact-eh-err2.s: New file.

2015-05-22  Catherine Moore  <clm@codesourcery.com>

	include/
	* bfdlink.h: Rename eh_frame_hdr to eh_frame_hdr_type.

2015-05-22  Catherine Moore  <clm@codesourcery.com>
	    Paul Brook <paul@codesourcery.com>

	ld/
	* emultempl/elf32.em (gld${EMULATION_NAME}_after_open):
	Add Compact EH support.
	* scripttempl/elf.sc: Handle .eh_frame_entry and .gnu_extab
	sections.

2015-05-22  Catherine Moore  <clm@codesourcery.com>

	ld/testsuite/
	* ld-mips-elf/compact-eh.ld: New linker script.
	* ld-mips-elf/compact-eh1.d: New.
	* ld-mips-elf/compact-eh1.s: New.
	* ld-mips-elf/compact-eh1a.s: New.
	* ld-mips-elf/compact-eh1b.s: New.
	* ld-mips-elf/compact-eh2.d: New.
	* ld-mips-elf/compact-eh2.s: New.
	* ld-mips-elf/compact-eh3.d: New.
	* ld-mips-elf/compact-eh3.s: New.
	* ld-mips-elf/compact-eh3a.s: New.
	* ld-mips-elf/compact-eh4.d: New.
	* ld-mips-elf/compact-eh5.d: New.
	* ld-mips-elf/compact-eh6.d: New.
	* ld-mips-elf/mips-elf.exp: Run new tests.

1 files changed, 53 insertions, 4 deletions

diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index e435e52..9807fe7 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -388,16 +388,41 @@ struct eh_frame_array_ent
 
 struct htab;
 
-struct eh_frame_hdr_info
+#define DWARF2_EH_HDR 1
+#define COMPACT_EH_HDR 2
+
+/* Endian-neutral code indicating that a function cannot be unwound.  */
+#define COMPACT_EH_CANT_UNWIND_OPCODE 0x015d5d01
+
+struct dwarf_eh_frame_hdr_info
 {
   struct htab *cies;
-  asection *hdr_sec;
-  unsigned int fde_count, array_count;
-  struct eh_frame_array_ent *array;
+  unsigned int fde_count;
   /* TRUE if .eh_frame_hdr should contain the sorted search table.
      We build it if we successfully read all .eh_frame input sections
      and recognize them.  */
   bfd_boolean table;
+  struct eh_frame_array_ent *array;
+};
+
+struct compact_eh_frame_hdr_info
+{
+  unsigned int allocated_entries;
+  /* eh_frame_entry fragments.  */
+  asection **entries;
+};
+
+struct eh_frame_hdr_info
+{
+  asection *hdr_sec;
+  unsigned int array_count;
+  bfd_boolean frame_hdr_is_compact;
+  union
+    {
+      struct dwarf_eh_frame_hdr_info dwarf;
+      struct compact_eh_frame_hdr_info compact;
+    }
+  u;
 };
 
 /* Enum used to identify target specific extensions to the elf_obj_tdata
@@ -1291,6 +1316,12 @@ struct elf_backend_data
      or give an error and return FALSE.  */
   bfd_boolean (*obj_attrs_handle_unknown) (bfd *, int);
 
+  /* Encoding used for compact EH tables.  */
+  int (*compact_eh_encoding) (struct bfd_link_info *);
+
+  /* Opcode representing no unwind.  */
+  int (*cant_unwind_opcode) (struct bfd_link_info *);
+
   /* This is non-zero if static TLS segments require a special alignment.  */
   unsigned static_tls_alignment;
 
@@ -1445,6 +1476,9 @@ struct bfd_elf_section_data
      field acts as a chain pointer.  */
   struct eh_cie_fde *fde_list;
 
+  /* Link from a text section to its .eh_frame_entry section.  */
+  asection *eh_frame_entry;
+
   /* A pointer used for various section optimizations.  */
   void *sec_info;
 };
@@ -1458,6 +1492,7 @@ struct bfd_elf_section_data
 #define elf_next_in_group(sec)	(elf_section_data(sec)->next_in_group)
 #define elf_fde_list(sec)	(elf_section_data(sec)->fde_list)
 #define elf_sec_group(sec)	(elf_section_data(sec)->sec_group)
+#define elf_section_eh_frame_entry(sec)	(elf_section_data(sec)->eh_frame_entry)
 
 #define xvec_get_elf_backend_data(xvec) \
   ((const struct elf_backend_data *) (xvec)->backend_data)
@@ -1983,8 +2018,15 @@ extern bfd_boolean _bfd_elf_strtab_emit
 extern void _bfd_elf_strtab_finalize
   (struct elf_strtab_hash *);
 
+extern bfd_boolean bfd_elf_parse_eh_frame_entries
+  (bfd *, struct bfd_link_info *);
+extern bfd_boolean _bfd_elf_parse_eh_frame_entry
+  (struct bfd_link_info *, asection *, struct elf_reloc_cookie *);
 extern void _bfd_elf_parse_eh_frame
   (bfd *, struct bfd_link_info *, asection *, struct elf_reloc_cookie *);
+extern bfd_boolean _bfd_elf_end_eh_frame_parsing
+  (struct bfd_link_info *info);
+
 extern bfd_boolean _bfd_elf_discard_section_eh_frame
   (bfd *, struct bfd_link_info *, asection *,
    bfd_boolean (*) (bfd_vma, void *), struct elf_reloc_cookie *);
@@ -1994,10 +2036,15 @@ extern bfd_vma _bfd_elf_eh_frame_section_offset
   (bfd *, struct bfd_link_info *, asection *, bfd_vma);
 extern bfd_boolean _bfd_elf_write_section_eh_frame
   (bfd *, struct bfd_link_info *, asection *, bfd_byte *);
+bfd_boolean _bfd_elf_write_section_eh_frame_entry
+  (bfd *, struct bfd_link_info *, asection *, bfd_byte *);
+extern bfd_boolean _bfd_elf_fixup_eh_frame_hdr (struct bfd_link_info *);
 extern bfd_boolean _bfd_elf_write_section_eh_frame_hdr
   (bfd *, struct bfd_link_info *);
 extern bfd_boolean _bfd_elf_eh_frame_present
   (struct bfd_link_info *);
+extern bfd_boolean _bfd_elf_eh_frame_entry_present
+  (struct bfd_link_info *);
 extern bfd_boolean _bfd_elf_maybe_strip_eh_frame_hdr
   (struct bfd_link_info *);
 
@@ -2021,6 +2068,8 @@ extern bfd_boolean _bfd_elf_create_dynamic_sections
   (bfd *, struct bfd_link_info *);
 extern bfd_boolean _bfd_elf_create_got_section
   (bfd *, struct bfd_link_info *);
+extern asection *_bfd_elf_section_for_symbol
+  (struct elf_reloc_cookie *, unsigned long, bfd_boolean);
 extern struct elf_link_hash_entry *_bfd_elf_define_linkage_sym
   (bfd *, struct bfd_link_info *, asection *, const char *);
 extern void _bfd_elf_init_1_index_section