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, 51 insertions, 3 deletions

diff --git a/gas/dw2gencfi.h b/gas/dw2gencfi.h
index 6e2c50e5143..6acd484c529 100644
--- a/gas/dw2gencfi.h
+++ b/gas/dw2gencfi.h
@@ -36,6 +36,7 @@ extern void cfi_finish (void);
 extern void cfi_new_fde (struct symbol *);
 extern void cfi_end_fde (struct symbol *);
 extern void cfi_set_return_column (unsigned);
+extern void cfi_set_sections (void);
 extern void cfi_add_advance_loc (struct symbol *);
 extern void cfi_add_label (const char *);
 
@@ -58,10 +59,18 @@ extern void cfi_add_CFA_restore_state (void);
 #define SUPPORT_FRAME_LINKONCE 0
 #endif
 
+#ifdef tc_cfi_reloc_for_encoding
+#define SUPPORT_COMPACT_EH 1
+#else
+#define SUPPORT_COMPACT_EH 0
+#endif
+
+#define MULTIPLE_FRAME_SECTIONS (SUPPORT_FRAME_LINKONCE || SUPPORT_COMPACT_EH)
+
 struct cfi_insn_data
 {
   struct cfi_insn_data *next;
-#if SUPPORT_FRAME_LINKONCE
+#if MULTIPLE_FRAME_SECTIONS
   segT cur_seg;
 #endif
   int insn;
@@ -100,10 +109,35 @@ struct cfi_insn_data
   } u;
 };
 
+/* An enumeration describing the Compact EH header format.  The least
+   significant bit is used to distinguish the entries.
+
+   Inline Compact:			Function offset [0]
+					Four chars of unwind data.
+   Out-of-line Compact:			Function offset [1]
+					Compact unwind data offset [0]
+   Legacy:				Function offset [1]
+					Unwind data offset [1]
+
+   The header type is initialized to EH_COMPACT_UNKNOWN until the
+   format is discovered by encountering a .fde_data entry.
+   Failure to find a .fde_data entry will cause an EH_COMPACT_LEGACY
+   header to be generated.  */
+
+enum {
+  EH_COMPACT_UNKNOWN,
+  EH_COMPACT_LEGACY,
+  EH_COMPACT_INLINE,
+  EH_COMPACT_OUTLINE,
+  EH_COMPACT_OUTLINE_DONE,
+  /* Outline if .cfi_inline_lsda used, otherwise legacy FDE.  */
+  EH_COMPACT_HAS_LSDA
+};
+
 struct fde_entry
 {
   struct fde_entry *next;
-#if SUPPORT_FRAME_LINKONCE
+#if MULTIPLE_FRAME_SECTIONS
   segT cur_seg;
 #endif
   symbolS *start_address;
@@ -112,13 +146,21 @@ struct fde_entry
   struct cfi_insn_data **last;
   unsigned char per_encoding;
   unsigned char lsda_encoding;
+  int personality_id;
   expressionS personality;
   expressionS lsda;
   unsigned int return_column;
   unsigned int signal_frame;
-#if SUPPORT_FRAME_LINKONCE
+#if MULTIPLE_FRAME_SECTIONS
   int handled;
 #endif
+  int eh_header_type;
+  /* Compact unwinding opcodes, not including the PR byte or LSDA.  */
+  int eh_data_size;
+  bfd_byte *eh_data;
+  /* For out of line tables and FDEs.  */
+  symbolS *eh_loc;
+  int sections;
 };
 
 /* The list of all FDEs that have been collected.  */
@@ -133,4 +175,10 @@ extern struct fde_entry *all_fde_data;
 #define CFI_val_encoded_addr	0x105
 #define CFI_label		0x106
 
+/* By default emit .eh_frame only, not .debug_frame.  */
+#define CFI_EMIT_eh_frame               (1 << 0)
+#define CFI_EMIT_debug_frame            (1 << 1)
+#define CFI_EMIT_target                 (1 << 2)
+#define CFI_EMIT_eh_frame_compact       (1 << 3)
+
 #endif /* DW2GENCFI_H */