[PATCH 2/2] gdb/dwarf: fix failed assertion in dwarf2_find_containing_comp_unit selftest

[Simon Marchi <simon.marchi@efficios.com>]

Commit 2f0521c0d6f6 ("gdb/dwarf: fix signature_type created with nullptr
section") added some asserts in the dwarf2_per_cu_data constructor to
verify that the passed dwarf2_per_bfd and dwarf2_section_info are not
nullptr.  However, the dummy dwarf2_per_cu_data objects create the in
dwarf2_find_containing_comp_unit selftests are passed nullptr for those
parameters.

I prefer to keep the asserts in place, as protection for the non-test
code and as self documentation, so fix this by passing some dummy
pointers in the test.

Change-Id: Ic7cdc1b976f7506041b651222234eefc998e473a
---
 gdb/dwarf2/read.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 2b060959c36f..59d79af004ca 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -20946,9 +20946,16 @@ namespace find_containing_comp_unit {
 static void
 run_test ()
 {
-  const auto create_dummy_per_cu = [] (sect_offset sect_off, unsigned int length)
+  char dummy_per_bfd;
+  char dummy_section;
+
+  const auto create_dummy_per_cu = [&] (sect_offset sect_off,
+					unsigned int length)
     {
-      return dwarf2_per_cu_data_up (new dwarf2_per_cu_data (nullptr, nullptr,
+      auto per_bfd = reinterpret_cast<dwarf2_per_bfd *> (&dummy_per_bfd);
+      auto section = reinterpret_cast<dwarf2_section_info *> (&dummy_section);
+
+      return dwarf2_per_cu_data_up (new dwarf2_per_cu_data (per_bfd, section,
 							    sect_off, length));
     };
 
-- 
2.48.1