Reviewed and approved by Jim Blandy

[deliverable/binutils-gdb.git] / gdb / testsuite / gdb.base / recurse.exp

diff --git a/gdb/testsuite/gdb.base/recurse.exp b/gdb/testsuite/gdb.base/recurse.exp
index 957f9497f0b96c532c93a76fe94bb2f6a654fe0b..bd1ecee60d95f1a7cc40e22128c0a6eb7af57aaa 100644 (file)
--- a/gdb/testsuite/gdb.base/recurse.exp
+++ b/gdb/testsuite/gdb.base/recurse.exp
@@ -123,9 +123,30 @@ proc recurse_tests {} {
            gdb_suppress_tests
        }
 
-       # Continue again.  We should have a watchpoint go out of scope now
+       # Continue again.  We should have a watchpoint go out of scope now.
+       #
+       # The former version expected the test to return to main().
+       # Now it expects the test to return to main or to stop in the
+       # function's epilogue.
+       # 
+       # The problem is that gdb needs to (but doesn't) understand
+       # function epilogues in the same way as for prologues.
+       # 
+       # If there is no hardware watchpoint (such as a x86 debug register),
+       # then watchpoints are done "the hard way" by single-stepping the
+       # target until the value of the watched variable changes.  If you
+       # are single-stepping, you will eventually step into an epilogue.
+       # When you do that, the "top" stack frame may become partially
+       # deconstructed (as when you pop the frame pointer, for instance),
+       # and from that point on, GDB can no longer make sense of the stack.
+       # 
+       # A test which stops in the epilogue is trying to determine when GDB
+       # leaves the stack frame in which the watchpoint was created.  It does
+       # this basically by watching for the frame pointer to change.  When
+       # the frame pointer changes, the test expects to be back in main, but
+       # instead it is still in the epilogue of the callee.
        if [gdb_test "continue" \
-           "Continuing.*\[Ww\]atchpoint.*deleted.*main \\(\\) .*" \
+           "Continuing.*\[Ww\]atchpoint.*deleted.*\(main \\(\\) \|21.*\}\).*" \
            "first instance watchpoint deleted when leaving scope"] then {
            gdb_suppress_tests;
        }