PR 15231: import bare DW_TAG_lexical_block

Local variables in lambdas are not accessible
https://sourceware.org/bugzilla/show_bug.cgi?id=15231

GDB: read_lexical_block_scope
  /* Ignore blocks with missing or invalid low and high pc attributes.  */
[...]
  if (!dwarf2_get_pc_bounds (die, &lowpc, &highpc, cu, NULL))
    return;

But sometimes there is:

FAIL: gcc-5.3.1-6.fc23.x86_64
 <2><92>: Abbrev Number: 11 (DW_TAG_lexical_block)
 <3><9c>: Abbrev Number: 13 (DW_TAG_structure_type)
    <9d>   DW_AT_name        : (indirect string, offset: 0x3c): <lambda()>
    [...]

Where DW_TAG_lexical_block has no attributes.  Such whole subtree is currently
dropped by GDB while I think it should just import all its children DIEs.

It even XFAIL->XPASSes gdb.ada/out_of_line_in_inlined.exp:
	commit 0fa7fe506c242b459c4c05d331e7c7d66fb52390
	Author: Joel Brobecker <brobecker@adacore.com>
	    out of line functions nested inside inline functions.
So I have removed that xfail.

gdb/ChangeLog
2016-05-30  Jan Kratochvil  <jan.kratochvil@redhat.com>

	PR c++/15231
	* dwarf2read.c (enum pc_bounds_kind): Add PC_BOUNDS_INVALID.
	(process_psymtab_comp_unit_reader, read_func_scope): Adjust callers.
	(read_lexical_block_scope): Import DIEs from bare DW_TAG_lexical_block.
	(read_call_site_scope): Adjust callers.
	(dwarf2_get_pc_bounds): Implement pc_bounds_invalid.
	(dwarf2_get_subprogram_pc_bounds, get_scope_pc_bounds): Adjust callers.

gdb/testsuite/ChangeLog
2016-05-30  Jan Kratochvil  <jan.kratochvil@redhat.com>

	PR c++/15231
	* gdb.ada/out_of_line_in_inlined.exp: Remove xfails.
	* gdb.dwarf2/dw2-lexical-block-bare.exp: New file.

3 files changed, 76 insertions, 6 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 4819203..8397f67 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2016-05-30  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	PR c++/15231
+	* gdb.ada/out_of_line_in_inlined.exp: Remove xfails.
+	* gdb.dwarf2/dw2-lexical-block-bare.exp: New file.
+
 2016-05-27  Pedro Alves  <palves@redhat.com>
 
 	* gdb.threads/attach-many-short-lived-threads.exp (bad_dejagnu):
diff --git a/gdb/testsuite/gdb.ada/out_of_line_in_inlined.exp b/gdb/testsuite/gdb.ada/out_of_line_in_inlined.exp
index 1ebd89f..8a3a4b1 100644
--- a/gdb/testsuite/gdb.ada/out_of_line_in_inlined.exp
+++ b/gdb/testsuite/gdb.ada/out_of_line_in_inlined.exp
@@ -23,20 +23,14 @@ if {[gdb_compile_ada "${srcfile}" "${binfile}" executable {debug optimize=-O2}]
 
 clean_restart ${testfile}
 
-# GCC currently is missing a DW_AT_origin attribute in one of the
-# lexical blocks, preventing GDB from creating a symbol for the
-# subprogram we want to break on.
-setup_xfail "*-*-*"
 gdb_test "break foo_o224_021.child1.child2" \
          "Breakpoint \[0-9\]+ at.*: file .*foo_o224_021.adb, line \[0-9\]+."
 
 gdb_run_cmd
-setup_xfail "*-*-*"
 gdb_test "" \
          "Breakpoint $decimal, foo_o224_021\\.child1\\.child2 \\(s=\\.\\.\\.\\).*"
 
 set opt_addr_in "($hex in)?"
-setup_xfail "*-*-*"
 gdb_test "bt" \
     [multi_line "#0 +$opt_addr_in +foo_o224_021\\.child1\\.child2 \\(s=\\.\\.\\.\\).*" \
                 "#1 +$opt_addr_in +foo_o224_021\\.child1 \\(\\).*" \
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-lexical-block-bare.exp b/gdb/testsuite/gdb.dwarf2/dw2-lexical-block-bare.exp
new file mode 100644
index 0000000..3f9411e
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-lexical-block-bare.exp
@@ -0,0 +1,70 @@
+# Copyright 2016 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/>.
+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 .S main.c
+
+# Make some DWARF for the test.
+set asm_file [standard_output_file $srcfile]
+Dwarf::assemble $asm_file {
+    cu {} {
+	compile_unit {
+	    {low_pc [gdb_target_symbol main] DW_FORM_addr}
+	    {high_pc [gdb_target_symbol main]+0x10000 DW_FORM_addr}
+	} {
+	    declare_labels integer_label
+
+	    integer_label: DW_TAG_base_type {
+		{DW_AT_byte_size 4 DW_FORM_sdata}
+		{DW_AT_encoding  @DW_ATE_signed}
+		{DW_AT_name      integer}
+	    }
+
+	    DW_TAG_subprogram {
+		{name main}
+		{DW_AT_external 1 flag}
+		{low_pc [gdb_target_symbol main] DW_FORM_addr}
+		{high_pc [gdb_target_symbol main]+0x10000 DW_FORM_addr}
+	    } {
+		DW_TAG_lexical_block {
+		} {
+		    DW_TAG_variable {
+			{DW_AT_name testvar}
+			    {DW_AT_type :$integer_label}
+			    {DW_AT_external 1 flag}
+			{DW_AT_location {
+			    DW_OP_addr [gdb_target_symbol main]
+			} SPECIAL_expr}
+		    }
+		}
+	    }
+	}
+    }
+}
+
+if { [prepare_for_testing ${testfile}.exp ${testfile} \
+			  [list $srcfile2 $asm_file] {nodebug}] } {
+    return -1
+}
+
+runto_main
+
+# FAILing GDB did print: No symbol "testvar" in current context.
+gdb_test "p testvar" { = -?[0-9]+}