[PATCH v3 1/2] gdb/testsuite: fix gdb.threads/threadcrash.exp on 32-bit arm targets

[Guinevere Larsen <blarsen@redhat.com>]

There are 2 issues with the test gdb.threads/threadcrash.exp on arm
targets, both relating to issues in how the targets handles gcores. The
first is that the test fails to cout the number of threads in the
inferior and the second is that GDB can't properly backtrace from a
gcore.

The first error is fixed on this commit by getting the convenience
variable _inferior_thread_count as opposed to calculating it based on
the output of "info threads"

For the second, this test just emits a single xfail referring back to PR
corefiles/31294, which tracks the issues with gcores in 32-bit arm
targets.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31294
---
 gdb/testsuite/gdb.threads/threadcrash.exp | 29 ++++++-----------------
 1 file changed, 7 insertions(+), 22 deletions(-)

diff --git a/gdb/testsuite/gdb.threads/threadcrash.exp b/gdb/testsuite/gdb.threads/threadcrash.exp
index 996e020d1e8..bf4534179e2 100644
--- a/gdb/testsuite/gdb.threads/threadcrash.exp
+++ b/gdb/testsuite/gdb.threads/threadcrash.exp
@@ -20,26 +20,6 @@
 # a gcore.
 
 
-# Check that the inferior has 7 threads, and return the number of threads (7).
-# We return the thread count so that, even if there is some error in the test,
-# the final log doesn't get flooded with failures.
-
-proc test_thread_count {} {
-    set thread_count 0
-
-    gdb_test_multiple "info threads" "getting thread count" -lbl {
-	-re "Thread" {
-	    incr thread_count
-	    exp_continue
-	}
-	-re "$::gdb_prompt " {
-	    gdb_assert {$thread_count == 7}
-	}
-    }
-
-    return $thread_count
-}
-
 # Use 'thread apply all backtrace' to check if all expected threads
 # are present, and stopped in the expected locations.  Set the global
 # TEST_LIST to be the a list of regexps expected to match all the
@@ -123,7 +103,8 @@ proc thread_apply_all {} {
 
 proc do_full_test {} {
     global test_list
-    set thread_count [test_thread_count]
+    set thread_count [get_valueof "" "\$_inferior_thread_count" 0]
+    gdb_assert {$thread_count == 7}
 
     thread_apply_all
 
@@ -230,4 +211,8 @@ test_live_inferior
 
 test_corefile
 
-test_gcore
+if { [is_aarch32_target] } {
+    kfail "gcore tests fail on 32-bit arm, see PR corefiles/31294"
+} else {
+    test_gcore
+}
-- 
2.43.0