[gdb/testsuite] Detect change instead of init in gdb.mi/mi-var-block.exp

On openSUSE Tumbleweed with target board unix/-m32, I run into:
...
PASS: gdb.mi/mi-var-block.exp: step at do_block_test 2
Expecting: ^(-var-update \*[^M
]+)?(\^done,changelist=\[{name="foo",in_scope="true",type_changed="false",has_more="0"},
{name="cb",in_scope="true",type_changed="false",has_more="0"}\][^M
]+[(]gdb[)] ^M
[ ]*)
-var-update *^M
^done,changelist=[{name="foo",in_scope="true",type_changed="false",has_more="0"}]^M
(gdb) ^M
FAIL: gdb.mi/mi-var-block.exp: update all vars: cb foo changed (unexpected output)
...

The problem is that the test-case attempts to detect a change in the cb
variable caused by this initialization:
...
void
do_block_tests ()
{
  int cb = 12;
...
but that only works if the stack location happens to be unequal to 12 before
the initialization.

Fix this by first initializing to 0, and then changing the value to 12:
...
-  int cb = 12;
+  int cb = 0;
+  cb = 12;
...
and detecting that change.

Tested on x86_64-linux.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29195

diff --git a/gdb/testsuite/gdb.mi/mi-var-block.exp b/gdb/testsuite/gdb.mi/mi-var-block.exp
index 2f8d39a6acd5f42221c078387a335dabceab5207..a1ef2d1ad526e087688581cc78fae68e3ac1ab7b 100644 (file)
--- a/gdb/testsuite/gdb.mi/mi-var-block.exp
+++ b/gdb/testsuite/gdb.mi/mi-var-block.exp
@@ -40,6 +40,11 @@ mi_gdb_load ${binfile}
 
 mi_runto do_block_tests
 
+# step to "cb = 12;"
+mi_step_to "do_block_tests" "" "var-cmd.c" \
+    [gdb_get_line_number "cb = 12;"] \
+    "step at do_block_test 0"
+
 # Test: c_variable-3.2
 # Desc: create cb and foo
 mi_create_varobj "cb" "cb" "create local variable cb"

diff --git a/gdb/testsuite/gdb.mi/var-cmd.c b/gdb/testsuite/gdb.mi/var-cmd.c
index fddb0d39a5ea632cdb2ef944b26c7950d9884bed..f3312788a80906728bde0e539e5ae615c83bb0a2 100644 (file)
--- a/gdb/testsuite/gdb.mi/var-cmd.c
+++ b/gdb/testsuite/gdb.mi/var-cmd.c
@@ -207,7 +207,8 @@ subroutine1 (int i, long *l)
 void
 do_block_tests ()
 {
-  int cb = 12;
+  int cb = 0;
+  cb = 12;
 
   {
     int foo;