RE: [PATCH v2] Change message when reaching end of reverse history.

["Metzger, Markus T" <markus.t.metzger@intel.com>]

>In a record session, when we move backward, GDB switches from normal
>execution to simulation. Moving forward again, the emulation continues
>until the end of the reverse history. When the end is reached, the
>execution stops, and a warning message is shown. This message has been
>modified to indicate that the forward emulation has reached the end, but
>the execution can continue as normal, and the recording will also continue.
>
>Before this patch, the warning message shown in that case was the same as
>in the reverse case. This meant that when the end of history was reached in
>either backward or forward emulation, the same message was displayed:
>
>"No more reverse-execution history."
>
>This message remains for backward emulation. However, in forward
>emulation,
>it has been modified to:
>
>"End of recorded history; following steps will be added to history."
>
>The reason for this change is that the initial message was deceiving, for
>the forward case, making the user believe that forward debugging could not
>continue.
>
>Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31224

Looks good to me with a small formatting nit.  CLI and documentation is
typically approved by Eli.


>---
> gdb/NEWS                                      |  5 ++++
> gdb/infrun.c                                  |  8 ++++-
> gdb/testsuite/gdb.btrace/non-stop.exp         | 30 ++++++++++++-------
> gdb/testsuite/gdb.reverse/break-precsave.exp  |  4 +--
> gdb/testsuite/gdb.reverse/break-reverse.exp   |  2 +-
> .../gdb.reverse/machinestate-precsave.exp     |  2 +-
> 6 files changed, 36 insertions(+), 15 deletions(-)
>
>diff --git a/gdb/NEWS b/gdb/NEWS
>index 2638b3e0d9c..f2e85776a53 100644
>--- a/gdb/NEWS
>+++ b/gdb/NEWS
>@@ -13,6 +13,11 @@
>   the background, resulting in faster startup.  This can be controlled
>   using "maint set dwarf synchronous".
>
>+* In a record session, when a forward emulation reaches the end of the
>reverse
>+  history, the warning message has been changed to indicate that the end of
>the
>+  history has been reached.  It also specifies that the forward execution can
>+  continue, and the recording will also continue.
>+
> * Changed commands
>
> disassemble
>diff --git a/gdb/infrun.c b/gdb/infrun.c
>index bbb98f6dcdb..c0f037c11a2 100644
>--- a/gdb/infrun.c
>+++ b/gdb/infrun.c
>@@ -9244,8 +9244,14 @@ print_no_history_reason (struct ui_out *uiout)
> {
>   if (uiout->is_mi_like_p ())
>     uiout->field_string ("reason", async_reason_lookup
>(EXEC_ASYNC_NO_HISTORY));
>+  else if (execution_direction == EXEC_FORWARD)
>+    uiout->text ("\nEnd of recorded history; following steps will be added to "
>+		 "history.\n");
>   else
>-    uiout->text ("\nNo more reverse-execution history.\n");
>+    {
>+      gdb_assert (execution_direction == EXEC_REVERSE);
>+      uiout->text ("\nNo more reverse-execution history.\n");
>+    }
> }
>
> /* Print current location without a level number, if we have changed
>diff --git a/gdb/testsuite/gdb.btrace/non-stop.exp
>b/gdb/testsuite/gdb.btrace/non-stop.exp
>index 62c940e4cd6..e4c91b793ae 100644
>--- a/gdb/testsuite/gdb.btrace/non-stop.exp
>+++ b/gdb/testsuite/gdb.btrace/non-stop.exp
>@@ -79,7 +79,7 @@ proc gdb_cont_to_bp_line { line threads nthreads } {
>         $nthreads
> }
>
>-proc gdb_cont_to_no_history { threads cmd nthreads } {
>+proc gdb_cont_to_no_history_backward { threads cmd nthreads } {
>     gdb_cont_to $threads $cmd \
>         [multi_line \
>              "No more reverse-execution history\." \
>@@ -89,6 +89,16 @@ proc gdb_cont_to_no_history { threads cmd nthreads }
>{
>         $nthreads
> }
>
>+proc gdb_cont_to_no_history_forward { threads cmd nthreads } {
>+    gdb_cont_to $threads $cmd \
>+        [multi_line \
>+             "End of recorded history; following steps will be added to history\." \
>+             "\[^\\\r\\\n\]*" \
>+             "\[^\\\r\\\n\]*" \
>+            ] \
>+        $nthreads
>+}
>+
> # trace the code between the two breakpoints
> with_test_prefix "prepare" {
>     gdb_cont_to_bp_line "$srcfile:$bp_1" all 2
>@@ -176,14 +186,14 @@ with_test_prefix "reverse-step" {
> with_test_prefix "continue" {
>     with_test_prefix "thread 1" {
> 	with_test_prefix "continue" {
>-	    gdb_cont_to_no_history 1 "continue" 1
>+	    gdb_cont_to_no_history_forward 1 "continue" 1
> 	    gdb_test "thread apply 1 info record" \
> 		".*Recorded \[0-9\]+ instructions \[^\\\r\\\n\]*"
> 	    gdb_test "thread apply 2 info record" \
> 		".*Replay in progress\.  At instruction 5\."
> 	}
> 	with_test_prefix "reverse-continue" {
>-	    gdb_cont_to_no_history 1 "reverse-continue" 1
>+	    gdb_cont_to_no_history_backward 1 "reverse-continue" 1
> 	    gdb_test "thread apply 1 info record" \
> 		".*Replay in progress\.  At instruction 1\."
> 	    gdb_test "thread apply 2 info record" \
>@@ -193,14 +203,14 @@ with_test_prefix "continue" {
>
>     with_test_prefix "thread 2" {
> 	with_test_prefix "continue" {
>-	    gdb_cont_to_no_history 2 "continue" 1
>+	    gdb_cont_to_no_history_forward 2 "continue" 1
> 	    gdb_test "thread apply 1 info record" \
> 		".*Replay in progress\.  At instruction 1\."
> 	    gdb_test "thread apply 2 info record" \
> 		".*Recorded \[0-9\]+ instructions \[^\\\r\\\n\]*"
> 	}
> 	with_test_prefix "reverse-continue" {
>-	    gdb_cont_to_no_history 2 "reverse-continue" 1
>+	    gdb_cont_to_no_history_backward 2 "reverse-continue" 1
> 	    gdb_test "thread apply 1 info record" \
> 		".*Replay in progress\.  At instruction 1\."
> 	    gdb_test "thread apply 2 info record" \
>@@ -215,8 +225,8 @@ with_test_prefix "no progress" {
>         gdb_test "thread apply 1 record goto end" ".*"
>         gdb_test "thread apply 2 record goto begin" ".*"
>
>-        gdb_cont_to_no_history 1 "continue" 1
>-        gdb_cont_to_no_history 1 "step" 1
>+        gdb_cont_to_no_history_forward 1 "continue" 1
>+        gdb_cont_to_no_history_forward 1 "step" 1
>         gdb_test "thread apply 1 info record" \
>             ".*Recorded \[0-9\]+ instructions \[^\\\r\\\n\]*"
>         gdb_test "thread apply 2 info record" \
>@@ -227,8 +237,8 @@ with_test_prefix "no progress" {
>         gdb_test "thread apply 1 record goto begin" ".*"
>         gdb_test "thread apply 2 record goto end" ".*"
>
>-        gdb_cont_to_no_history 2 "continue" 1
>-        gdb_cont_to_no_history 2 "step" 1
>+        gdb_cont_to_no_history_forward 2 "continue" 1
>+        gdb_cont_to_no_history_forward 2 "step" 1
>         gdb_test "thread apply 1 info record" \
>             ".*Replay in progress\.  At instruction 1\."
>         gdb_test "thread apply 2 info record" \
>@@ -238,7 +248,7 @@ with_test_prefix "no progress" {
>     with_test_prefix "all" {
>         gdb_test "thread apply all record goto begin" ".*"
>
>-        gdb_cont_to_no_history all "continue" 2
>+        gdb_cont_to_no_history_forward all "continue" 2
>         gdb_test "thread apply 1 info record" \
>             ".*Recorded \[0-9\]+ instructions \[^\\\r\\\n\]*"
>         gdb_test "thread apply 2 info record" \
>diff --git a/gdb/testsuite/gdb.reverse/break-precsave.exp
>b/gdb/testsuite/gdb.reverse/break-precsave.exp
>index b9d94681247..89ce9d7e854 100644
>--- a/gdb/testsuite/gdb.reverse/break-precsave.exp
>+++ b/gdb/testsuite/gdb.reverse/break-precsave.exp
>@@ -73,7 +73,7 @@ proc precsave_tests {} {
> 	-re ".*Breakpoint $decimal,.*$srcfile:$end_location.*$gdb_prompt $"
>{
> 	    pass "go to end of main forward"
> 	}
>-	-re "No more reverse-execution history.* end of main .*$gdb_prompt
>$" {
>+	-re "End of recorded history; following steps will be added to history.*
>end of main .*$gdb_prompt $" {

This line got too long.

> 	    pass "go to end of main forward"
> 	}
>     }
>@@ -103,7 +103,7 @@ proc precsave_tests {} {
> 	-re ".*Breakpoint $decimal,.*$srcfile:$end_location.*$gdb_prompt $"
>{
> 	    pass "end of record log"
> 	}
>-	-re "No more reverse-execution history.* end of main .*$gdb_prompt
>$" {
>+	-re "End of recorded history; following steps will be added to history.*
>end of main .*$gdb_prompt $" {

This line got too long.

> 	    pass "end of record log"
> 	}
>     }
>diff --git a/gdb/testsuite/gdb.reverse/break-reverse.exp
>b/gdb/testsuite/gdb.reverse/break-reverse.exp
>index 1dd327ca654..e9c799a506d 100644
>--- a/gdb/testsuite/gdb.reverse/break-reverse.exp
>+++ b/gdb/testsuite/gdb.reverse/break-reverse.exp
>@@ -80,7 +80,7 @@ gdb_test_multiple "continue" "end of record log" {
>     -re ".*Breakpoint $decimal,.*$srcfile:$end_location.*$gdb_prompt $" {
> 	pass "end of record log"
>     }
>-    -re "No more reverse-execution history.* end of main .*$gdb_prompt $" {
>+    -re "End of recorded history; following steps will be added to history.* end
>of main .*$gdb_prompt $" {

This line got too long.

> 	pass "end of record log"
>     }
> }
>diff --git a/gdb/testsuite/gdb.reverse/machinestate-precsave.exp
>b/gdb/testsuite/gdb.reverse/machinestate-precsave.exp
>index 19c5934bfdf..6b3a949e23a 100644
>--- a/gdb/testsuite/gdb.reverse/machinestate-precsave.exp
>+++ b/gdb/testsuite/gdb.reverse/machinestate-precsave.exp
>@@ -85,7 +85,7 @@ gdb_test_multiple "continue" "go to end of main
>forward" {
>     -re ".*Breakpoint $decimal,.*$srcfile:$endmain.*$gdb_prompt $"  {
> 	pass "go to end of main forward"
>     }
>-    -re "No more reverse-execution history.* end main .*$gdb_prompt $" {
>+    -re "End of recorded history; following steps will be added to history.* end
>main .*$gdb_prompt $" {

This line got too long.

> 	pass "go to end of main forward"
>     }
> }
>--
>2.42.0

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