[PATCH v2 03/11] change gdb.base/skip.exp to use finish instead of step

[Bruno Larsen <blarsen@redhat.com>]

skip.exp was making use of a fixed amount of step commands to exit
some functions.  This caused some problems when testing GDB with clang,
as it doesn't add epilogue information for functions, along with some
unreliable results depending on the version of GCC, as sometimes gdb
could stop in either of the 2 lines after 2 steps:

x = bax ((bar (), foo ()))
test_skip_file_and_function ();

whereas using clang will always stop on the second line after 1 step.
To deal with GCC unreliability, this test case used to use the question
mechanism from gdb_test, but Pedro mentioned that this is a mis-use of
that feature, and it doesn't deal with the clang case.  This commit
changes it to use gdb_test_multiple and deal with all possible cases,
only considering it a pass when test_skip_file_and_function () is
reached.
---
 gdb/testsuite/gdb.base/skip.exp | 164 +++++++++++++++++++++++++-------
 1 file changed, 131 insertions(+), 33 deletions(-)

diff --git a/gdb/testsuite/gdb.base/skip.exp b/gdb/testsuite/gdb.base/skip.exp
index 7c71bb07a84..5021b696668 100644
--- a/gdb/testsuite/gdb.base/skip.exp
+++ b/gdb/testsuite/gdb.base/skip.exp
@@ -117,9 +117,23 @@ with_test_prefix "step after deleting 1" {
 	return
     }
 
-    gdb_test "step" "foo \\(\\) at.*" "step 1"
-    gdb_test "step" ".*" "step 2" ; # Return from foo()
-    gdb_test "step" "main \\(\\) at.*" "step 3"
+    gdb_test "step" "foo \\(\\) at.*" "step"
+    # step until we are after foo and bar calls, while making sure that
+    # we never step into baz.
+    gdb_test_multiple "step" "step until main" {
+	# gcc stop in this line before continuing
+	-re ".*x = baz \\(\\(bar \\(\\), foo \\(\\)\\)\\);.*" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*\}\r\n$gdb_prompt $" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*test_skip_file_and_function \\(\\).*" {
+	    pass "step until main"
+	}
+    }
 }
 
 # Now disable the skiplist entry for  skip1.c.  We should now
@@ -137,13 +151,27 @@ with_test_prefix "step after disabling 3" {
     }
 
     gdb_test "step" "bar \\(\\) at.*" "step 1"
-    gdb_test "step" ".*" "step 2"; # Return from bar()
-    # With gcc 9.2.0 we jump once back to main before entering foo here.
-    # If that happens try to step a second time.
-    gdb_test "step" "foo \\(\\) at.*" "step 3" \
-	"main \\(\\) at .*\r\n$gdb_prompt " "step"
-    gdb_test "step" ".*" "step 4"; # Return from foo()
-    gdb_test "step" "main \\(\\) at.*" "step 5"
+    # guarantee that we jump once back to main before entering foo here.
+    # This makes behavior more consistent over different compilers and
+    # different compiler versions
+    gdb_test "finish" ".*" "finish 1"; # Return to main()
+    gdb_test "step" "foo \\(\\) at.*" "step 2"
+    # step until we are after foo and bar calls, while making sure that
+    # we never step into baz.
+    gdb_test_multiple "step" "step until main" {
+	# gcc stop in this line before continuing
+	-re ".*x = baz \\(\\(bar \\(\\), foo \\(\\)\\)\\);.*" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*\}\r\n$gdb_prompt $" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*test_skip_file_and_function \\(\\).*" {
+	    pass "step until main"
+	}
+    }
 }
 
 # Enable skiplist entry 3 and make sure we step over it like before.
@@ -159,9 +187,23 @@ with_test_prefix "step after enable 3" {
 	return
     }
 
-    gdb_test "step" "foo \\(\\) at.*" "step 1"
-    gdb_test "step" ".*" "step 2"; # Return from foo()
-    gdb_test "step" "main \\(\\) at.*" "step 3"
+    gdb_test "step" "foo \\(\\) at.*" "step"
+    # step until we are after foo and bar calls, while making sure that
+    # we never step into baz.
+    gdb_test_multiple "step" "step until main" {
+	# gcc stop in this line before continuing
+	-re ".*x = baz \\(\\(bar \\(\\), foo \\(\\)\\)\\);.*" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*\}\r\n$gdb_prompt $" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*test_skip_file_and_function \\(\\).*" {
+	    pass "step until main"
+	}
+    }
 }
 
 # Admin tests (disable,enable,delete).
@@ -230,9 +272,23 @@ with_test_prefix "step using -fi" {
 
     gdb_test_no_output "skip disable"
     gdb_test_no_output "skip enable 5"
-    gdb_test "step" "foo \\(\\) at.*" "step 1"
-    gdb_test "step" ".*" "step 2"; # Return from foo()
-    gdb_test "step" "main \\(\\) at.*" "step 3"
+    gdb_test "step" "foo \\(\\) at.*" "step"
+    # step until we are after foo and bar calls, while making sure that
+    # we never step into baz.
+    gdb_test_multiple "step" "step until main" {
+	# gcc stop in this line before continuing
+	-re ".*x = baz \\(\\(bar \\(\\), foo \\(\\)\\)\\);.*" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*\}\r\n$gdb_prompt $" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*test_skip_file_and_function \\(\\).*" {
+	    pass "step until main"
+	}
+    }
 }
 
 with_test_prefix "step using -gfi" {
@@ -242,9 +298,23 @@ with_test_prefix "step using -gfi" {
 
     gdb_test_no_output "skip disable"
     gdb_test_no_output "skip enable 6"
-    gdb_test "step" "foo \\(\\) at.*" "step 1"
-    gdb_test "step" ".*" "step 2"; # Return from foo()
-    gdb_test "step" "main \\(\\) at.*" "step 3"
+    gdb_test "step" "foo \\(\\) at.*" "step"
+    # step until we are after foo and bar calls, while making sure that
+    # we never step into baz.
+    gdb_test_multiple "step" "step until main" {
+	# gcc stop in this line before continuing
+	-re ".*x = baz \\(\\(bar \\(\\), foo \\(\\)\\)\\);.*" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*\}\r\n$gdb_prompt $" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*test_skip_file_and_function \\(\\).*" {
+	    pass "step until main"
+	}
+    }
 }
 
 with_test_prefix "step using -fu for baz" {
@@ -255,13 +325,27 @@ with_test_prefix "step using -fu for baz" {
     gdb_test_no_output "skip disable"
     gdb_test_no_output "skip enable 7"
     gdb_test "step" "bar \\(\\) at.*" "step 1"
-    gdb_test "step" ".*" "step 2"; # Return from bar()
-    # With gcc 9.2.0 we jump once back to main before entering foo here.
-    # If that happens try to step a second time.
-    gdb_test "step" "foo \\(\\) at.*" "step 3" \
-	"main \\(\\) at .*\r\n$gdb_prompt " "step"
-    gdb_test "step" ".*" "step 4"; # Return from foo()
-    gdb_test "step" "main \\(\\) at.*" "step 5"
+    # guarantee that we jump once back to main before entering foo here.
+    # This makes behavior more consistent over different compilers and
+    # different compiler versions
+    gdb_test "finish" ".*" "finish 1"; # Return to main()
+    gdb_test "step" "foo \\(\\) at.*" "step 2"
+    # step until we are after foo and bar calls, while making sure that
+    # we never step into baz.
+    gdb_test_multiple "step" "step until main" {
+	# gcc stop in this line before continuing
+	-re ".*x = baz \\(\\(bar \\(\\), foo \\(\\)\\)\\);.*" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*\}\r\n$gdb_prompt $" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*test_skip_file_and_function \\(\\).*" {
+	    pass "step until main"
+	}
+    }
 }
 
 with_test_prefix "step using -rfu for baz" {
@@ -272,13 +356,27 @@ with_test_prefix "step using -rfu for baz" {
     gdb_test_no_output "skip disable"
     gdb_test_no_output "skip enable 8"
     gdb_test "step" "bar \\(\\) at.*" "step 1"
-    gdb_test "step" ".*" "step 2"; # Return from bar()
-    # With gcc 9.2.0 we jump once back to main before entering foo here.
-    # If that happens try to step a second time.
-    gdb_test "step" "foo \\(\\) at.*" "step 3" \
-	"main \\(\\) at .*\r\n$gdb_prompt " "step"
-    gdb_test "step" ".*" "step 4"; # Return from foo()
-    gdb_test "step" "main \\(\\) at.*" "step 5"
+    # guarantee that we jump once back to main before entering foo here.
+    # This makes behavior more consistent over different compilers and
+    # different compiler versions
+    gdb_test "finish" ".*" "finish 1"; # Return to main()
+    gdb_test "step" "foo \\(\\) at.*" "step 2"
+    # step until we are after foo and bar calls, while making sure that
+    # we never step into baz.
+    gdb_test_multiple "step" "step until main" {
+	# gcc stop in this line before continuing
+	-re ".*x = baz \\(\\(bar \\(\\), foo \\(\\)\\)\\);.*" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*\}\r\n$gdb_prompt $" {
+	    send_gdb "step\n"
+	    exp_continue
+	}
+	-re ".*test_skip_file_and_function \\(\\).*" {
+	    pass "step until main"
+	}
+    }
 }
 
 # Test -fi + -fu.
-- 
2.31.1