[binutils-gdb] Fix method naming bug in new DWARF indexer

[binutils-gdb] Fix method naming bug in new DWARF indexer

[Tom Tromey]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=6acc36f71dfc60e357496174672103f133f85e97

commit 6acc36f71dfc60e357496174672103f133f85e97
Author: Tom Tromey <tromey@adacore.com>
Date:   Thu Apr 21 09:37:24 2022 -0600

    Fix method naming bug in new DWARF indexer
    
    Pedro pointed out that gdb-add-index is much slower with the new DWARF
    indexer.  He also noticed that, in some cases, the generated
    .gdb_index would have the wrong fully-qualified name for a method.
    
    I tracked this down to a bug in the indexer.  If a type could have
    methods but was marked as a declaration, the indexer was ignoring it.
    However, this meant that the internal map to find the qualified name
    was not updated for this container.

Diff:
---
 gdb/dwarf2/abbrev.c                      | 11 +++++
 gdb/dwarf2/read.c                        |  7 ++-
 gdb/testsuite/gdb.dwarf2/struct-decl.exp | 74 ++++++++++++++++++++++++++++++++
 3 files changed, 90 insertions(+), 2 deletions(-)

diff --git a/gdb/dwarf2/abbrev.c b/gdb/dwarf2/abbrev.c
index 2db5ea15aca..4ca27eaa7e0 100644
--- a/gdb/dwarf2/abbrev.c
+++ b/gdb/dwarf2/abbrev.c
@@ -280,6 +280,17 @@ abbrev_table::read (struct dwarf2_section_info *section,
 	    = (cur_abbrev->tag == DW_TAG_namespace
 	       || cur_abbrev->tag == DW_TAG_enumeration_type);
 	}
+      else if ((cur_abbrev->tag == DW_TAG_structure_type
+		|| cur_abbrev->tag == DW_TAG_class_type
+		|| cur_abbrev->tag == DW_TAG_union_type)
+	       && cur_abbrev->has_children)
+	{
+	  /* We have to record this as interesting, regardless of how
+	     DW_AT_declaration is set, so that any subsequent
+	     DW_AT_specification pointing at a child of this will get
+	     the correct scope.  */
+	  cur_abbrev->interesting = true;
+	}
       else if (has_hardcoded_declaration
 	       && (cur_abbrev->tag != DW_TAG_variable || !has_external))
 	cur_abbrev->interesting = false;
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index d6fccf83dd2..37e9587e43e 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -18091,8 +18091,11 @@ cooked_indexer::scan_attributes (dwarf2_per_cu_data *scanning_per_cu,
      that is ok.  Similarly, we allow an external variable without a
      location; those are resolved via minimal symbols.  */
   if (is_declaration && !for_specification
-      && (abbrev->tag != DW_TAG_variable
-	  || (*flags & IS_STATIC) != 0))
+      && !(abbrev->tag == DW_TAG_variable && (*flags & IS_STATIC) == 0)
+      && !((abbrev->tag == DW_TAG_class_type
+	    || abbrev->tag == DW_TAG_structure_type
+	    || abbrev->tag == DW_TAG_union_type)
+	   && abbrev->has_children))
     {
       *linkage_name = nullptr;
       *name = nullptr;
diff --git a/gdb/testsuite/gdb.dwarf2/struct-decl.exp b/gdb/testsuite/gdb.dwarf2/struct-decl.exp
new file mode 100644
index 00000000000..739eaaabb2b
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/struct-decl.exp
@@ -0,0 +1,74 @@
+# Copyright 2022 Free Software Foundation, Inc.
+
+# 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, see <http://www.gnu.org/licenses/>.
+
+# Check that the DWARF reader works when a DW_AT_specification refers
+# into a type hierarchy that is marked as a declaration.
+
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+if {![dwarf2_support]} {
+    return 0
+}
+
+standard_testfile main.c -debug.S
+
+# Set up the DWARF for the test.
+set asm_file [standard_output_file $srcfile2]
+Dwarf::assemble $asm_file {
+    global srcfile
+
+    cu {} {
+	DW_TAG_compile_unit {
+	    {DW_AT_language @DW_LANG_C_plus_plus}
+	    {DW_AT_name     $srcfile}
+	    {DW_AT_comp_dir /tmp}
+
+	} {
+	    declare_labels origin
+
+	    # The new indexer was ignoring types that were marked as
+	    # declarations, even if they could contain methods --
+	    # which meant that if a method referred back to them via a
+	    # specification, it would get the wrong name.
+	    DW_TAG_structure_type {
+		{DW_AT_byte_size 8 DW_FORM_sdata}
+		{DW_AT_encoding  @DW_ATE_signed}
+		{DW_AT_name the_type}
+		{DW_AT_declaration 1 DW_FORM_flag_present}
+	    } {
+		origin: DW_TAG_subprogram {
+		    {DW_AT_name "method"}
+		    {DW_AT_declaration 1 DW_FORM_flag_present}
+		}
+	    }
+
+	    # The low and high PC are phony: we just need an address
+	    # range that is valid in the program, so we use the main
+	    # function's range.
+	    DW_TAG_subprogram {
+		{DW_AT_specification :$origin}
+		{MACRO_AT_range main}
+	    }
+	}
+    }
+}
+
+if {[prepare_for_testing "failed to prepare" ${testfile} \
+	 [list $srcfile $asm_file] {nodebug}]} {
+    return -1
+}
+
+gdb_breakpoint "the_type::method" message