Re: "optimized out" on gdb.base/gdb1090.exp

[Edjunior Barbosa Machado <emachado at linux dot vnet dot ibm dot com>]

On 04/11/2011 11:20 PM, Yao Qi wrote:
> On 04/12/2011 09:16 AM, Edjunior Barbosa Machado wrote:
> > Hi,
> >
> > running the testcase gdb.base/gdb1090.exp on ppc64 using gcc 4.3.4,
> > noticed an unexpected error in the second test:
> >
> > #1  0x00000000100005dc in foo () at
> > ../../../gdb.git/gdb/testsuite/gdb.base/gdb1090.c:39^M
> > 39        marker (s24);^M
> > (gdb) PASS: gdb.base/gdb1090.exp: up from marker
> > print s24^M
> > $1 =<optimized out>^M
> > (gdb) FAIL: gdb.base/gdb1090.exp: print s24
> >
> > According to readelf output, s24 uses r9, which is a volatile register.
> > However, the content is properly printed when using gcc 4.4.5 (var s24
> > goes to r30, which is not volatile on power)
> >
> > Just wondering, can we consider this last test as untested (or even
> > pass) when print returns "optimized out", since it does not print
> > garbage (which was the original issue from gdb/1090)?
>
> If we set breakpoint directly on a certain line of main(), and check the
> value of `s24' in main().  Can we get the value of `s24'?  If we can, we
> may modify test case a little bit, instead of marking this case as
> untested (or even pass).

It works fine if I set a breakpoint in the end of foo() (which is the function where 's24' is declared).
My only concern is if this check in the same frame will not affect the main purpose of the testcase. If there is no problem with this, please consider the patch below.

Thanks,
--
Edjunior

2011-04-12  Edjunior Machado  <emachado@br.ibm.com>

	* testsuite/gdb.base/gdb1090.exp: change breakpoint location to	read the
	content of 's24' correctly (avoiding "optimized out").
	* testsuite/gdb.base/gdb1090.c: add comment in order to set breakpoint.

diff --git a/gdb/testsuite/gdb.base/gdb1090.c b/gdb/testsuite/gdb.base/gdb1090.c
index 22f2cec..72ebd2e 100644
--- a/gdb/testsuite/gdb.base/gdb1090.c
+++ b/gdb/testsuite/gdb.base/gdb1090.c
@@ -37,7 +37,7 @@ void foo ()
   s24.field_0 = 1170;
   s24.field_1 = 64701;
   marker (s24);
-  return;
+  return; /* break-here */
 }
 
 int main ()
diff --git a/gdb/testsuite/gdb.base/gdb1090.exp b/gdb/testsuite/gdb.base/gdb1090.exp
index a15fd04..0ff5c73 100644
--- a/gdb/testsuite/gdb.base/gdb1090.exp
+++ b/gdb/testsuite/gdb.base/gdb1090.exp
@@ -40,12 +40,9 @@ gdb_start
 gdb_reinitialize_dir $srcdir/$subdir
 gdb_load ${binfile}
 
-if ![runto marker] then {
-    perror "couldn't run to breakpoint"
-    continue
-}
-gdb_test "up" ".*foo.*" "up from marker"
+gdb_breakpoint [gdb_get_line_number "break-here"]
 
+gdb_run_cmd
 gdb_test_multiple "print s24" "print s24" {
     -re "\\\$\[0-9\]* = \\{field_0 = 1170, field_1 = 64701\\}\r\n$gdb_prompt $" {
 	pass "print s24"