Re: Python: fetch value when building gdb.Value object

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

On Sat, 01 Oct 2011 12:22:46 +0200, Pedro Alves wrote:
> On Saturday 01 October 2011 10:28:52, Jan Kratochvil wrote:
> >    # Test memory error.
> >    gdb_test "python print gdb.parse_and_eval('*(int*)0')" "gdb.MemoryError: Cannot access memory at address 0x0.*"
> > +  gdb_test "python inval = gdb.parse_and_eval('*(int*)0')" "gdb.MemoryError: Cannot access memory at address 0x0.*"
> 
> I see this is already the case, but just a reminder that this will fail
> (or rather the write will succeed) on targets without an MMU.  We should
> skip it with something like:

So checked it in (I am aware the existing code elsewhere in GDB testsuite is
a bit different).


Thanks,
Jan


http://sourceware.org/ml/gdb-cvs/2011-10/msg00002.html

--- src/gdb/testsuite/ChangeLog	2011/09/30 15:07:32	1.2867
+++ src/gdb/testsuite/ChangeLog	2011/10/01 11:02:10	1.2868
@@ -1,3 +1,12 @@
+2011-10-01  Jan Kratochvil  <jan.kratochvil@redhat.com>
+	    Pedro Alves  <pedro@codesourcery.com>
+
+	* gdb.python/py-value.exp (test_value_in_inferior): New variable
+	can_read_0, test for it.
+	(python print gdb.parse_and_eval('*(int*)0')): Rename to ...
+	(parse_and_eval with memory error): ... here, make it untested if
+	can_read_0.
+
 2011-09-30  Marek Polacek  <mpolacek@redhat.com>
 
 	* gdb.python/python.exp (verify pagination beforehand)
--- src/gdb/testsuite/gdb.python/py-value.exp	2011/07/26 18:38:55	1.22
+++ src/gdb/testsuite/gdb.python/py-value.exp	2011/10/01 11:02:11	1.23
@@ -216,8 +216,25 @@
   # Test address attribute
   gdb_test "python print 'result =', arg0.address" "= 0x\[\[:xdigit:\]\]+" "Test address attribute"
 
+  # Test displaying a variable that is temporarily at a bad address.
+  # But if we can examine what's at memory address 0, then we'll also be
+  # able to display it without error.  Don't run the test in that case.
+  set can_read_0 0
+  gdb_test_multiple "x 0" "memory at address 0" {
+      -re "0x0:\[ \t\]*Cannot access memory at address 0x0\r\n$gdb_prompt $" { }
+      -re "0x0:\[ \t\]*Error accessing memory address 0x0\r\n$gdb_prompt $" { }
+      -re "\r\n$gdb_prompt $" {
+	  set can_read_0 1
+      }
+  }
+
   # Test memory error.
-  gdb_test "python print gdb.parse_and_eval('*(int*)0')" "gdb.MemoryError: Cannot access memory at address 0x0.*"
+  set test "parse_and_eval with memory error"
+  if {$can_read_0} {
+    untested $test
+  } else {
+    gdb_test "python print gdb.parse_and_eval('*(int*)0')" "gdb.MemoryError: Cannot access memory at address 0x0.*" $test
+  }
 
   # Test string fetches,  both partial and whole.
   gdb_test "print st" "\"divide et impera\""