gdb.reverse/time-reverse.exp: test both time syscall and C time function

Instead of only testing this on systems that have a SYS_time syscall,
test it everywhere using the time(2) C function, and in addition, run
the tests again using the SYS_time syscall.

The C variant ensures that if some platform uses some syscall we are
not aware of yet, we'll still exercise it, and likely fail, at which
point we should teach GDB about the syscall.

The explicit syscall variant is useful on platforms where the C
function does not call a syscall at all by default, e.g., on some
systems the C time function wraps an implementation provided by the
vDSO.

Approved-By: Tom de Vries <tdevries@suse.de>
Change-Id: Id4b755d76577d02c46b8acbfa249d9c31b587633

2 files changed, 57 insertions, 22 deletions

diff --git a/gdb/testsuite/gdb.reverse/time-reverse.c b/gdb/testsuite/gdb.reverse/time-reverse.c
index 668fb10..c22ecd8 100644
--- a/gdb/testsuite/gdb.reverse/time-reverse.c
+++ b/gdb/testsuite/gdb.reverse/time-reverse.c
@@ -20,6 +20,12 @@
 #include <sys/syscall.h>
 #include <unistd.h>
 
+#ifdef USE_SYSCALL
+# define my_time(TLOC) syscall (SYS_time, TLOC)
+#else
+# define my_time(TLOC) time (TLOC)
+#endif
+
 void
 marker1 (void)
 {
@@ -36,7 +42,7 @@ int
 main (void)
 {
   marker1 ();
-  syscall (SYS_time, &time_global);
+  my_time (&time_global);
   marker2 ();
   return 0;
 }
diff --git a/gdb/testsuite/gdb.reverse/time-reverse.exp b/gdb/testsuite/gdb.reverse/time-reverse.exp
index befda65..91f9911 100644
--- a/gdb/testsuite/gdb.reverse/time-reverse.exp
+++ b/gdb/testsuite/gdb.reverse/time-reverse.exp
@@ -23,33 +23,62 @@ require supports_reverse
 
 standard_testfile
 
-require {expr [have_syscall time]}
+# MODE is either "syscall" for testing the time syscall explicitly, or
+# "c" for testing the C time(2) function.
+proc test {mode} {
+    set options {debug}
 
-if { [prepare_for_testing "failed to prepare" $testfile $srcfile] } {
-    return -1
-}
+    if {$mode == "syscall"} {
+	lappend options additional_flags=-DUSE_SYSCALL
+    } elseif {$mode != "c"} {
+	error "unrecognized mode: $mode"
+    }
 
-runto_main
+    if { [prepare_for_testing "failed to prepare" $::testfile-$mode $::srcfile $options] } {
+	return
+    }
 
-if [supports_process_record] {
-    # Activate process record/replay
-    gdb_test_no_output "record" "turn on process record"
-}
+    runto_main
+
+    if [supports_process_record] {
+	# Activate process record/replay
+	gdb_test_no_output "record" "turn on process record"
+    }
+
+    gdb_test "break marker2" \
+	"Breakpoint $::decimal at $::hex: file .*$::srcfile, line $::decimal.*" \
+	"set breakpoint at marker2"
+
+    gdb_continue_to_breakpoint "marker2" ".*$::srcfile:.*"
 
-gdb_test "break marker2" \
-    "Breakpoint $decimal at $hex: file .*$srcfile, line $decimal.*" \
-    "set breakpoint at marker2"
+    gdb_test "break marker1" \
+	"Breakpoint $::decimal at $::hex: file .*$::srcfile, line $::decimal.*" \
+	"set breakpoint at marker1"
 
-gdb_continue_to_breakpoint "marker2" ".*$srcfile:.*"
+    gdb_test "reverse-continue" ".*$::srcfile:$::decimal.*" "reverse to marker1"
 
-gdb_test "break marker1" \
-    "Breakpoint $decimal at $hex: file .*$srcfile, line $decimal.*" \
-    "set breakpoint at marker1"
+    # If the variable was recorded properly, the old contents (-1)
+    # will be remembered.  If not, new contents (current time) will be
+    # used, and the test will fail.
 
-gdb_test "reverse-continue" ".*$srcfile:$decimal.*" "reverse to marker1"
+    gdb_test "print time_global" ".* = -1" "check time record"
+}
 
-# If the variable was recorded properly on syscall, the old contents (-1)
-# will be remembered.  If not, new contents (current time) will be used,
-# and the test will fail.
+# Test both using the syscall explicitly, and using the time(2) C
+# function.
+#
+# The C variant ensures that if some platform uses some syscall we are
+# not aware of yet, we'll still exercise it (and likely fail).
+#
+# The explicit syscall variant is useful on platforms where the C
+# function does not call a syscall at all by default, e.g., on some
+# systems the C time function wraps an implementation provided by the
+# vDSO.
 
-gdb_test "print time_global" ".* = -1" "check time record"
+foreach_with_prefix mode {syscall c} {
+    if {$mode == "syscall" && ![have_syscall time]} {
+	continue
+    }
+
+    test $mode
+}