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Re: [commit] Support displaced stepping on S/390
- From: Daniel Jacobowitz <drow at false dot org>
- To: Ulrich Weigand <uweigand at de dot ibm dot com>
- Cc: gdb-patches at sourceware dot org
- Date: Sun, 27 Sep 2009 17:12:27 -0400
- Subject: Re: [commit] Support displaced stepping on S/390
- References: <200909272100.n8RL0Dwv012931@d12av02.megacenter.de.ibm.com>
On Sun, Sep 27, 2009 at 11:00:13PM +0200, Ulrich Weigand wrote:
> Hello,
>
> on s390 the non-stop cases were failing because we do not yet support
> displaced stepping at all. The following patch implements a basic
> version that should support most common compiler-generated code.
>
> Tested on s390(x)-linux, fixes the non-stop test cases.
> Committed to mainline.
FYI, I have a local patch to issue an error if you try to connect to a
remote target in non-stop mode and the target supports non-stop but
gdb does not know how to do displaced stepping. Clearly the check
shouldn't be remote specific - but I didn't post it because I couldn't
figure out how where to put the error to work for native too.
Attached for reference. I am perfectly happy to commit this if
someone thinks it's an improvement, but I'd rather figure out where to
handle native first...
--
Daniel Jacobowitz
CodeSourcery
2009-09-21 Daniel Jacobowitz <dan@codesourcery.com>
gdb/
* inferior.h (missing_displaced_stepping): Declare.
* infrun.c (need_displaced_stepping): New function, from
use_displaced_stepping.
(use_displaced_stepping): Use need_displaced_stepping.
(missing_displaced_stepping): New function.
* remote.c (remote_start_remote): Require displaced stepping support
for non-stop.
gdb/testsuite/
* lib/mi-support.exp (mi_gdb_target_cmd): Loosen non-stop error check.
* gdb.mi/mi-nonstop-exit.exp, gdb.mi/mi-nonstop.exp,
gdb.mi/mi-nsintrall.exp, gdb.mi/mi-nsmoribund.exp,
gdb.mi/mi-nsthrexec.exp: Remove perror and fail after mi_run_to_main.
Index: gdb/inferior.h
===================================================================
--- gdb/inferior.h (revision 262049)
+++ gdb/inferior.h (revision 262050)
@@ -357,6 +357,11 @@ extern int debug_displaced;
void displaced_step_dump_bytes (struct ui_file *file,
const gdb_byte *buf, size_t len);
+/* Return non-zero if displaced stepping should be used to step
+ over breakpoints, but is not supported. */
+
+int missing_displaced_stepping (struct gdbarch *gdbarch);
+
/* Possible values for gdbarch_call_dummy_location. */
#define ON_STACK 1
Index: gdb/remote.c
===================================================================
--- gdb/remote.c (revision 262049)
+++ gdb/remote.c (revision 262050)
@@ -2788,6 +2788,9 @@ remote_start_remote (struct ui_out *uiou
if (!rs->non_stop_aware)
error (_("Non-stop mode requested, but remote does not support non-stop"));
+ if (missing_displaced_stepping (target_gdbarch))
+ error (_("Non-stop mode requested, but displaced stepping is not supported on this architecture"));
+
putpkt ("QNonStop:1");
getpkt (&rs->buf, &rs->buf_size, 0);
Index: gdb/testsuite/lib/mi-support.exp
===================================================================
--- gdb/testsuite/lib/mi-support.exp (revision 262049)
+++ gdb/testsuite/lib/mi-support.exp (revision 262050)
@@ -365,7 +365,7 @@ proc mi_gdb_target_cmd { targetname seri
sleep 5
continue
}
- -re "Non-stop mode requested, but remote does not support non-stop.*$mi_gdb_prompt" {
+ -re "Non-stop mode requested, but .*$mi_gdb_prompt" {
unsupported "Non-stop mode not supported"
return 1
}
Index: gdb/testsuite/gdb.mi/mi-nsthrexec.exp
===================================================================
--- gdb/testsuite/gdb.mi/mi-nsthrexec.exp (revision 262049)
+++ gdb/testsuite/gdb.mi/mi-nsthrexec.exp (revision 262050)
@@ -63,7 +63,6 @@ mi_gdb_test "-gdb-set target-async 1" ".
detect_async
if { [mi_run_to_main] < 0 } {
- perror "mi-nsthrexec.exp tests suppressed"
continue
}
Index: gdb/testsuite/gdb.mi/mi-nsintrall.exp
===================================================================
--- gdb/testsuite/gdb.mi/mi-nsintrall.exp (revision 262049)
+++ gdb/testsuite/gdb.mi/mi-nsintrall.exp (revision 262050)
@@ -53,7 +53,6 @@ mi_gdb_test "-gdb-set target-async 1" ".
detect_async
if { [mi_run_to_main] < 0 } {
- perror "mi-nsintrall.exp tests suppressed"
continue
}
Index: gdb/testsuite/gdb.mi/mi-nsmoribund.exp
===================================================================
--- gdb/testsuite/gdb.mi/mi-nsmoribund.exp (revision 262049)
+++ gdb/testsuite/gdb.mi/mi-nsmoribund.exp (revision 262050)
@@ -53,7 +53,6 @@ mi_gdb_test "-gdb-set target-async 1" ".
detect_async
if { [mi_run_to_main] < 0 } {
- perror "mi-nsmoribund.exp tests suppressed"
continue
}
Index: gdb/testsuite/gdb.mi/mi-nonstop-exit.exp
===================================================================
--- gdb/testsuite/gdb.mi/mi-nonstop-exit.exp (revision 262049)
+++ gdb/testsuite/gdb.mi/mi-nonstop-exit.exp (revision 262050)
@@ -54,7 +54,6 @@ mi_gdb_test "-gdb-set target-async 1" ".
detect_async
if { [mi_run_to_main] < 0 } {
- perror "mi-nonstop-exit.exp tests suppressed"
continue
}
@@ -65,7 +64,6 @@ mi_expect_stop "exited-normally" "" "" "
# Run the program again.
if { [mi_run_to_main] < 0 } {
- fail "run (2)"
continue
}
Index: gdb/testsuite/gdb.mi/mi-nonstop.exp
===================================================================
--- gdb/testsuite/gdb.mi/mi-nonstop.exp (revision 262049)
+++ gdb/testsuite/gdb.mi/mi-nonstop.exp (revision 262050)
@@ -54,7 +54,6 @@ mi_gdb_test "-gdb-set target-async 1" ".
detect_async
if { [mi_run_to_main] < 0 } {
- perror "mi-nonstop.exp tests suppressed"
continue
}
Index: gdb/infrun.c
===================================================================
--- gdb/infrun.c (revision 262049)
+++ gdb/infrun.c (revision 262050)
@@ -739,19 +739,38 @@ Debugger's willingness to use displaced
breakpoints is %s.\n"), value);
}
-/* Return non-zero if displaced stepping can/should be used to step
+/* Return non-zero if displaced stepping should be used to step
over breakpoints. */
static int
-use_displaced_stepping (struct gdbarch *gdbarch)
+need_displaced_stepping (struct gdbarch *gdbarch)
{
return (((can_use_displaced_stepping == can_use_displaced_stepping_auto
&& non_stop)
|| can_use_displaced_stepping == can_use_displaced_stepping_on)
- && gdbarch_displaced_step_copy_insn_p (gdbarch)
&& !RECORD_IS_USED);
}
+/* Return non-zero if displaced stepping can/should be used to step
+ over breakpoints. */
+
+static int
+use_displaced_stepping (struct gdbarch *gdbarch)
+{
+ return (need_displaced_stepping (gdbarch)
+ && gdbarch_displaced_step_copy_insn_p (gdbarch));
+}
+
+/* Return non-zero if displaced stepping should be used to step
+ over breakpoints, but is not supported. */
+
+int
+missing_displaced_stepping (struct gdbarch *gdbarch)
+{
+ return (need_displaced_stepping (gdbarch)
+ && !gdbarch_displaced_step_copy_insn_p (gdbarch));
+}
+
/* Clean out any stray displaced stepping state. */
static void
displaced_step_clear (void)