DWARF-5: .debug_names index consumer

Some testcases needed to be updated as they were missing
.debug_aranges.  While that does not matter for no-index (as GDB
builds the mapping internally during dwarf2_build_psymtabs_hard) and
neither for .gdb_index (as GDB uses that internally built mapping
which it stores into .gdb_index) it does matter for .debug_names as
that simply assumes existing .debug_aranges from GCC.

gdb/ChangeLog:
2017-12-08  Jan Kratochvil  <jan.kratochvil@redhat.com>
	    Pedro Alves  <palves@redhat.com>

	* defs.h (elf_sym_fns_debug_names): New declaration.
	* dwarf2read.c: Include "hash_enum.h".
	(mapped_debug_names): New.
	(struct dwarf2_per_objfile): Add debug_names, debug_aranges and
	debug_names_table.
	(dwarf2_elf_names): Add ".debug_names" and ".debug_aranges".
	(struct dwz_file): Add debug_names.
	(dwarf2_per_objfile::locate_sections): Handle debug_names and
	debug_aranges.
	(locate_dwz_sections): Handle debug_names.
	(create_signatured_type_table_from_debug_names)
	(create_addrmap_from_aranges): New.
	(dwarf2_read_index): Update function comment.
	(dwarf5_augmentation): Moved up.
	(read_debug_names_from_section, create_cus_from_debug_names_list)
	(create_cus_from_debug_names, dwarf2_read_debug_names): New.
	(dwarf5_djb_hash): Moved up.
	(dw2_debug_names_iterator): New.
	(read_indirect_string_at_offset): New declaration.
	(mapped_debug_names::namei_to_name)
	(dw2_debug_names_iterator::find_vec_in_debug_names)
	(dw2_debug_names_iterator::next, dw2_debug_names_lookup_symbol)
	(dw2_debug_names_dump, dw2_debug_names_expand_symtabs_for_function)
	(dw2_debug_names_expand_symtabs_matching, dwarf2_debug_names_functions):
	New.
	(dwarf2_initialize_objfile): Return also elf_sym_fns_debug_names.
	(debug_names::djb_hash): Rename it to dwarf5_djb_hash.
	(debug_names::build): Update djb_hash caller.
	(write_debug_names): Move out and rename augmentation to
	dwarf5_augmentation.
	* elfread.c (elf_sym_fns_debug_names): New.
	* psymtab.h (dwarf2_debug_names_functions): New declaration.
	* symfile.h (struct dwarf2_debug_sections): Add debug_names and
	debug_aranges.
	* xcoffread.c (dwarf2_xcoff_names): Add debug_names and debug_aranges.

gdb/testsuite/ChangeLog:
2017-12-08  Jan Kratochvil  <jan.kratochvil@redhat.com>
	    Pedro Alves  <palves@redhat.com>

	* gdb.base/maint.exp (check for .gdb_index): Check also for
	.debug_names.
	* gdb.dlang/watch-loc.c (.debug_aranges): New.
	* gdb.dwarf2/dw2-case-insensitive-debug.S: Likewise.
	* gdb.dwarf2/gdb-index.exp (check if index present, .gdb_index used)
	(.gdb_index used after symbol reloading): Support also .debug_names.
	* gdb.mi/dw2-ref-missing-frame-func.c (.debug_aranges): New.

gdb/ChangeLog

@@ -1,3 +1,42 @@
+2017-12-08  Jan Kratochvil  <jan.kratochvil@redhat.com>
+	    Pedro Alves  <palves@redhat.com>
+
+	* defs.h (elf_sym_fns_debug_names): New declaration.
+	* dwarf2read.c: Include "hash_enum.h".
+	(mapped_debug_names): New.
+	(struct dwarf2_per_objfile): Add debug_names, debug_aranges and
+	debug_names_table.
+	(dwarf2_elf_names): Add ".debug_names" and ".debug_aranges".
+	(struct dwz_file): Add debug_names.
+	(dwarf2_per_objfile::locate_sections): Handle debug_names and
+	debug_aranges.
+	(locate_dwz_sections): Handle debug_names.
+	(create_signatured_type_table_from_debug_names)
+	(create_addrmap_from_aranges): New.
+	(dwarf2_read_index): Update function comment.
+	(dwarf5_augmentation): Moved up.
+	(read_debug_names_from_section, create_cus_from_debug_names_list)
+	(create_cus_from_debug_names, dwarf2_read_debug_names): New.
+	(dwarf5_djb_hash): Moved up.
+	(dw2_debug_names_iterator): New.
+	(read_indirect_string_at_offset): New declaration.
+	(mapped_debug_names::namei_to_name)
+	(dw2_debug_names_iterator::find_vec_in_debug_names)
+	(dw2_debug_names_iterator::next, dw2_debug_names_lookup_symbol)
+	(dw2_debug_names_dump, dw2_debug_names_expand_symtabs_for_function)
+	(dw2_debug_names_expand_symtabs_matching, dwarf2_debug_names_functions):
+	New.
+	(dwarf2_initialize_objfile): Return also elf_sym_fns_debug_names.
+	(debug_names::djb_hash): Rename it to dwarf5_djb_hash.
+	(debug_names::build): Update djb_hash caller.
+	(write_debug_names): Move out and rename augmentation to
+	dwarf5_augmentation.
+	* elfread.c (elf_sym_fns_debug_names): New.
+	* psymtab.h (dwarf2_debug_names_functions): New declaration.
+	* symfile.h (struct dwarf2_debug_sections): Add debug_names and
+	debug_aranges.
+	* xcoffread.c (dwarf2_xcoff_names): Add debug_names and debug_aranges.
+
 2017-12-08  Pedro Alves  <palves@redhat.com>
 
 	* common/hash_enum.h: New file.

gdb/defs.h

@@ -683,6 +683,7 @@ extern void initialize_inferiors (void);
 
 extern const struct sym_fns elf_sym_fns_lazy_psyms;
 extern const struct sym_fns elf_sym_fns_gdb_index;
+extern const struct sym_fns elf_sym_fns_debug_names;
 
 /* * Special block numbers */
 

gdb/elfread.c

@@ -1403,6 +1403,23 @@ const struct sym_fns elf_sym_fns_gdb_index =
   &dwarf2_gdb_index_functions
 };
 
+/* The same as elf_sym_fns, but not registered and uses the
+   DWARF-specific .debug_names index rather than psymtab.  */
+const struct sym_fns elf_sym_fns_debug_names =
+{
+  elf_new_init,			/* init anything gbl to entire symab */
+  elf_symfile_init,		/* read initial info, setup for sym_red() */
+  elf_symfile_read,		/* read a symbol file into symtab */
+  NULL,				/* sym_read_psymbols */
+  elf_symfile_finish,		/* finished with file, cleanup */
+  default_symfile_offsets,	/* Translate ext. to int. relocatin */
+  elf_symfile_segments,		/* Get segment information from a file.  */
+  NULL,
+  default_symfile_relocate,	/* Relocate a debug section.  */
+  &elf_probe_fns,		/* sym_probe_fns */
+  &dwarf2_debug_names_functions
+};
+
 /* STT_GNU_IFUNC resolver vector to be installed to gnu_ifunc_fns_p.  */
 
 static const struct gnu_ifunc_fns elf_gnu_ifunc_fns =

gdb/psymtab.h

@@ -33,6 +33,7 @@ extern struct bcache *psymbol_bcache_get_bcache (struct psymbol_bcache *);
 extern const struct quick_symbol_functions psym_functions;
 
 extern const struct quick_symbol_functions dwarf2_gdb_index_functions;
+extern const struct quick_symbol_functions dwarf2_debug_names_functions;
 
 /* Ensure that the partial symbols for OBJFILE have been loaded.  If
    VERBOSE is non-zero, then this will print a message when symbols

gdb/symfile.h

@@ -582,6 +582,8 @@ struct dwarf2_debug_sections {
   struct dwarf2_section_names frame;
   struct dwarf2_section_names eh_frame;
   struct dwarf2_section_names gdb_index;
+  struct dwarf2_section_names debug_names;
+  struct dwarf2_section_names debug_aranges;
   /* This field has no meaning, but exists solely to catch changes to
      this structure which are not reflected in some instance.  */
   int sentinel;

gdb/testsuite/ChangeLog

@@ -1,3 +1,14 @@
+2017-12-08  Jan Kratochvil  <jan.kratochvil@redhat.com>
+	    Pedro Alves  <palves@redhat.com>
+
+	* gdb.base/maint.exp (check for .gdb_index): Check also for
+	.debug_names.
+	* gdb.dlang/watch-loc.c (.debug_aranges): New.
+	* gdb.dwarf2/dw2-case-insensitive-debug.S: Likewise.
+	* gdb.dwarf2/gdb-index.exp (check if index present, .gdb_index used)
+	(.gdb_index used after symbol reloading): Support also .debug_names.
+	* gdb.mi/dw2-ref-missing-frame-func.c (.debug_aranges): New.
+
 2017-12-08  Yao Qi  <yao.qi@linaro.org>
 
 	* gdb.arch/aarch64-tagged-pointer.c (main): Update.

gdb/testsuite/gdb.base/maint.exp

@@ -89,10 +89,13 @@ if ![runto_main] then {
         perror "tests suppressed"
 }
 
-# If we're using .gdb_index there will be no psymtabs.
+# If we're using .gdb_index or .debug_names there will be no psymtabs.
 set have_gdb_index 0
-gdb_test_multiple "maint info sections .gdb_index" "check for .gdb_index" {
-    -re ": .gdb_index.*$gdb_prompt $" {
+gdb_test_multiple "maint info sections .gdb_index .debug_names" "check for .gdb_index" {
+    -re ": \\.gdb_index .*\r\n$gdb_prompt $" {
+	set have_gdb_index 1
+    }
+    -re ": \\.debug_names .*\r\n$gdb_prompt $" {
 	set have_gdb_index 1
     }
     -re ".*$gdb_prompt $" {

gdb/testsuite/gdb.dlang/watch-loc.c

@@ -34,3 +34,23 @@ main (void)
   return _Dmain ();
 }
 
+/* The .debug_names-based index support depends on .debug_aranges
+   generated by GCC.  (.gdb_index includes a gdb-generated map
+   instead.)  */
+asm (
+"	.pushsection	.debug_aranges,\"\",@progbits \n"
+"	.4byte	.Laranges_end - .Laranges_start \n"	// Length of Address Ranges Info
+".Laranges_start: \n"
+"	.2byte	0x2 \n"	// DWARF Version
+"	.4byte	0 \n" // .Ldebug_info0 - Offset of Compilation Unit Info
+"	.byte	4 \n"	// Size of Address
+"	.byte	0 \n"	// Size of Segment Descriptor
+"	.2byte	0 \n"	// Pad to 16 byte boundary
+"	.2byte	0 \n"
+"	.4byte	_Dmain \n"	// Address
+"	.4byte	0x1000 \n"	// Length
+"	.4byte	0 \n"
+"	.4byte	0 \n"
+".Laranges_end: \n"
+"	.popsection \n"
+);

gdb/testsuite/gdb.dwarf2/dw2-case-insensitive-debug.S

@@ -57,6 +57,24 @@
 	.byte		0			/* End of children of CU */
 .Lcu1_end:
 
+	/* The .debug_names-based index support depends on
+	   .debug_aranges generated by GCC.  (.gdb_index includes a
+	   gdb-generated map instead.)	*/
+	.section	.debug_aranges,"",@progbits
+	.4byte	.Laranges_end - .Laranges_start	// Length of Address Ranges Info
+.Laranges_start:
+	.2byte	0x2	// DWARF Version
+	.4byte	0 // .Ldebug_info0 - Offset of Compilation Unit Info
+	.byte	PTRBITS / 8	// Size of Address
+	.byte	0	// Size of Segment Descriptor
+	.2byte	0	// Pad to 16 byte boundary
+	.2byte	0
+	PTRBYTE	cu_text_start	// Address
+	PTRBYTE	0x1000 // cu_text_end - cu_text_start	// Length
+	PTRBYTE	0
+	PTRBYTE	0
+.Laranges_end:
+
 /* Abbrev table */
 	.section .debug_abbrev
 .Labbrev1_begin:

gdb/testsuite/gdb.dwarf2/gdb-index.exp

@@ -58,7 +58,7 @@ proc add_gdb_index { program } {
     return ${program_with_index}
 }
 
-# Build a copy of the program with .gdb_index.
+# Build a copy of the program with an index (.gdb_index/.debug_names).
 # But only if the toolchain didn't already create one: gdb doesn't support
 # building an index from a program already using one.
 
@@ -67,6 +67,9 @@ gdb_test_multiple "mt print objfiles ${testfile}" $test {
     -re "gdb_index.*${gdb_prompt} $" {
 	set binfile_with_index $binfile
     }
+    -re "debug_names.*${gdb_prompt} $" {
+	set binfile_with_index $binfile
+    }
     -re "Psymtabs.*${gdb_prompt} $" {
 	set binfile_with_index [add_gdb_index $binfile]
 	if { ${binfile_with_index} == "" } {
@@ -75,16 +78,16 @@ gdb_test_multiple "mt print objfiles ${testfile}" $test {
     }
 }
 
-# Ok, we have a copy of $binfile with .gdb_index.
+# Ok, we have a copy of $binfile with an index.
 # Restart gdb and verify the index was used.
 
 clean_restart ${binfile_with_index}
 gdb_test "mt print objfiles ${testfile}" \
-    "gdb_index.*" \
-    ".gdb_index used"
+    "(gdb_index|debug_names).*" \
+    "index used"
 
-# Make gdb re-read symbols and see if .gdb_index still gets used.
-# symtab/15885
+# Make gdb re-read symbols and see if .gdb_index/.debug_names still
+# gets used.  symtab/15885
 
 # There is gdb_touch_execfile, but it doesn't handle remote hosts.
 # Is touch portable enough?
@@ -98,5 +101,5 @@ if ![runto_main] {
     return -1
 }
 gdb_test "mt print objfiles ${testfile}" \
-    "gdb_index.*" \
-    ".gdb_index used after symbol reloading"
+    "(gdb_index|debug_names).*" \
+    "index used after symbol reloading"

gdb/testsuite/gdb.mi/dw2-ref-missing-frame-func.c

@@ -52,3 +52,24 @@ asm ("func_loopfb_end:");
 
 asm (".globl cu_text_end");
 asm ("cu_text_end:");
+
+/* The .debug_names-based index support depends on .debug_aranges
+   generated by GCC.  (.gdb_index includes a gdb-generated map
+   instead.)  */
+asm (
+"	.pushsection	.debug_aranges,\"\",@progbits \n"
+"	.4byte	.Laranges_end - .Laranges_start \n"	// Length of Address Ranges Info
+".Laranges_start: \n"
+"	.2byte	0x2 \n"	// DWARF Version
+"	.4byte	0 \n" // .Ldebug_info0 - Offset of Compilation Unit Info
+"	.byte	4 \n"	// Size of Address
+"	.byte	0 \n"	// Size of Segment Descriptor
+"	.2byte	0 \n"	// Pad to 16 byte boundary
+"	.2byte	0 \n"
+"	.4byte	cu_text_start \n"	// Address
+"	.4byte	cu_text_end - cu_text_start \n"	// Length
+"	.4byte	0 \n"
+"	.4byte	0 \n"
+".Laranges_end: \n"
+"	.popsection \n"
+);

gdb/xcoffread.c

@@ -174,6 +174,8 @@ static const struct dwarf2_debug_sections dwarf2_xcoff_names = {
   { ".dwframe", NULL },
   { NULL, NULL }, /* eh_frame */
   { NULL, NULL }, /* gdb_index */
+  { NULL, NULL }, /* debug_names */
+  { NULL, NULL }, /* debug_aranges */
   23
 };