[committed][gdb] Fix segfault in solib_contains_address_p

[Tom de Vries <tdevries@suse.de>]

Hi,

Starting commit bb2a67773c "Use a std::vector in target_section_table" we run
into:
...
ERROR: GDB process no longer exists
GDB process exited with wait status 22239 exp12 0 0 CHILDKILLED SIGABRT
UNRESOLVED: gdb.base/exec-invalid-sysroot.exp: continue to exec catchpoint
...
which reproduces as:
...
Thread 1 "gdb" received signal SIGSEGV, Segmentation fault.
solib_contains_address_p (address=4196111, solib=0x1dd9970)
    at /home/vries/gdb_versions/devel/src/gdb/solib.c:1120
1120      for (target_section &p : solib->sections->sections)
(gdb) p solib->sections->sections
Cannot access memory at address 0x0
...

Fix this by handling solib->sections == nullptr in solib_contains_address_p.

Build and reg-tested on x86_64-linux.

Committed to trunk.

Thanks,
- Tom

[gdb] Fix segfault in solib_contains_address_p

gdb/ChangeLog:

2020-10-14  Tom de Vries  <tdevries@suse.de>

	PR gdb/26733
	* solib.c (solib_contains_address_p): Handle
	'solib->sections == nullptr'.

---
 gdb/solib.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/gdb/solib.c b/gdb/solib.c
index b4864429e9..28f6a4ecbf 100644
--- a/gdb/solib.c
+++ b/gdb/solib.c
@@ -1113,6 +1113,9 @@ bool
 solib_contains_address_p (const struct so_list *const solib,
 			  CORE_ADDR address)
 {
+  if (solib->sections == nullptr)
+    return false;
+
   for (target_section &p : *solib->sections)
     if (p.addr <= address && address < p.endaddr)
       return true;