[PATCH 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 | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/gdb/testsuite/gdb.threads/threadcrash.exp b/gdb/testsuite/gdb.threads/threadcrash.exp
index d3e3494cbea..362c4c5879d 100644
--- a/gdb/testsuite/gdb.threads/threadcrash.exp
+++ b/gdb/testsuite/gdb.threads/threadcrash.exp
@@ -27,12 +27,9 @@
 proc test_thread_count {} {
     set thread_count 0
 
-    gdb_test_multiple "info threads" "getting thread count" -lbl {
-	-re "\(Thread\|LWP\)" {
-	    incr thread_count
-	    exp_continue
-	}
-	-re "$::gdb_prompt " {
+    gdb_test_multiple "print \$_inferior_thread_count" "getting thread count" {
+	-re ".* = (\[0-9]+).*" {
+	    set thread_count $expect_out(1,string)
 	    gdb_assert {$thread_count == 7}
 	}
     }
@@ -230,4 +227,8 @@ test_live_inferior
 
 test_corefile
 
-test_gcore
+if { [is_aarch32_target] } {
+    xfail "gcore tests fail on 32-bit arm, see PR corefiles/31294"
+} else {
+    test_gcore
+}
-- 
2.43.0