[gdb/symtab] Don't complain about function decls

[ Requires "[gdb/symtab] Don't complain about inlined functions" as
submitted here (
https://sourceware.org/pipermail/gdb-patches/2022-September/191762.html ). ]

With the test-case included in this patch, we get:
...
(gdb) ptype main^M
During symbol reading: cannot get low and high bounds for subprogram DIE \
  at 0xc1^M
type = int (void)^M
(gdb) FAIL: gdb.dwarf2/anon-ns-fn.exp: ptype main without complaints
...

The DIE causing the complaint is a function declaration:
...
 <2><c1>: Abbrev Number: 3 (DW_TAG_subprogram)
    <c2>   DW_AT_name        : foo
    <c8>   DW_AT_declaration : 1
...
which is referred to from the DIE representing the function definition:
...
 <1><f4>: Abbrev Number: 7 (DW_TAG_subprogram)
    <f5>   DW_AT_specification: <0xc1>
    <f9>   DW_AT_low_pc      : 0x4004c7
    <101>   DW_AT_high_pc     : 0x7
...
which does contain the low and high bounds.

Fix this by not complaining about function declarations.

Tested on x86_64-linux.

3 files changed, 67 insertions, 1 deletions

diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 812d9c6..8e42c0f 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -12051,7 +12051,9 @@ read_func_scope (struct die_info *die, struct dwarf2_cu *cu)
 	   && attr->is_nonnegative ()
 	   && (attr->as_nonnegative () == DW_INL_inlined
 	       || attr->as_nonnegative () == DW_INL_declared_inlined));
-      if (!external_p && !inlined_p)
+      attr = dwarf2_attr (die, DW_AT_declaration, cu);
+      bool decl_p = attr != nullptr && attr->as_boolean ();
+      if (!external_p && !inlined_p && !decl_p)
 	complaint (_("cannot get low and high bounds "
 		     "for subprogram DIE at %s"),
 		   sect_offset_str (die->sect_off));
diff --git a/gdb/testsuite/gdb.dwarf2/anon-ns-fn.cc b/gdb/testsuite/gdb.dwarf2/anon-ns-fn.cc
new file mode 100644
index 0000000..62a6505
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/anon-ns-fn.cc
@@ -0,0 +1,31 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   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/>.  */
+
+namespace
+{
+  void
+  foo (void)
+  {
+  }
+}
+
+int
+main (void)
+{
+  foo ();
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.dwarf2/anon-ns-fn.exp b/gdb/testsuite/gdb.dwarf2/anon-ns-fn.exp
new file mode 100644
index 0000000..71b1a47
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/anon-ns-fn.exp
@@ -0,0 +1,33 @@
+# 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/>.
+
+if {[skip_cplus_tests]} { continue }
+
+standard_testfile .cc
+
+if [prepare_for_testing "failed to prepare" $testfile $srcfile {debug c++}] {
+    return -1
+}
+
+set cmd "ptype main"
+
+set re \
+    [multi_line \
+	 $cmd \
+	 "type = int \\(void\\)"]
+
+with_complaints 5 {
+    gdb_test $cmd $re "$cmd without complaints"
+}