Re: [PATCH v6] Change message when reaching end of reverse history.

[Guinevere Larsen <blarsen@redhat.com>]

On 8/2/24 1:43 PM, Alex Chronopoulos wrote:
> 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 has changed for these two cases. Backward emulation:
>
> "Reached end of recorded history; stopping.
> Backward execution from here not possible."
>
> Forward emulation:
>
> "Reached end of recorded history; stopping.
> Following forward execution 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
> ---

Hi! I think this is good to go in, but I would like Markus to chime in 
before pushing, since he mantains the other record subsystem, so for now

Reviewed-By: Guinevere Larsen <blarsen@redhat.com>

>   gdb/NEWS                                      |  5 +++
>   gdb/infrun.c                                  |  9 +++++-
>   .../gdb.btrace/multi-thread-step.exp          |  6 ++--
>   gdb/testsuite/gdb.btrace/nohist.exp           |  2 +-
>   gdb/testsuite/gdb.btrace/non-stop.exp         | 32 ++++++++++++-------
>   gdb/testsuite/gdb.btrace/stepi.exp            | 14 ++++----
>   gdb/testsuite/gdb.reverse/break-precsave.exp  |  6 ++--
>   gdb/testsuite/gdb.reverse/break-reverse.exp   |  4 +--
>   .../gdb.reverse/machinestate-precsave.exp     |  2 +-
>   gdb/testsuite/gdb.reverse/sigall-precsave.exp |  2 +-
>   gdb/testsuite/gdb.reverse/sigall-reverse.exp  |  2 +-
>   .../gdb.reverse/singlejmp-reverse.exp         |  6 ++--
>   12 files changed, 57 insertions(+), 33 deletions(-)
>
> diff --git a/gdb/NEWS b/gdb/NEWS
> index 50c033a7cfd..5d457b37796 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -20,6 +20,11 @@
>   * MTE (Memory Tagging Extension) debugging is now supported on AArch64 baremetal
>     targets.
>   
> +* 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.
> +
>   *** Changes in GDB 15
>   
>   * The MPX commands "show/set mpx bound" have been deprecated, as Intel
> diff --git a/gdb/infrun.c b/gdb/infrun.c
> index 06b454bf78f..a0d1b99be3e 100644
> --- a/gdb/infrun.c
> +++ b/gdb/infrun.c
> @@ -9266,8 +9266,15 @@ 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 ("\nReached end of recorded history; stopping.\nFollowing "
> +		 "forward execution will be added to history.\n");
>     else
> -    uiout->text ("\nNo more reverse-execution history.\n");
> +    {
> +      gdb_assert (execution_direction == EXEC_REVERSE);
> +      uiout->text ("\nReached end of recorded history; stopping.\nBackward "
> +		   "execution from here not possible.\n");
> +    }
>   }
>   
>   /* Print current location without a level number, if we have changed
> diff --git a/gdb/testsuite/gdb.btrace/multi-thread-step.exp b/gdb/testsuite/gdb.btrace/multi-thread-step.exp
> index 154db9ae515..cd20e8ad9f0 100644
> --- a/gdb/testsuite/gdb.btrace/multi-thread-step.exp
> +++ b/gdb/testsuite/gdb.btrace/multi-thread-step.exp
> @@ -111,14 +111,14 @@ proc test_cont {} {
>       with_test_prefix "cont" {
>           gdb_test "thread 1" ".*"
>           with_test_prefix "thread 1" {
> -            gdb_test "continue" "No more reverse-execution history.*"
> +            gdb_test "continue" "Reached end of recorded history.*"
>   
>               check_not_replaying 1
>               check_replay_insn 2 2
>           }
>           gdb_test "thread 2" ".*"
>           with_test_prefix "thread 2" {
> -            gdb_test "continue" "No more reverse-execution history.*"
> +            gdb_test "continue" "Reached end of recorded history.*"
>   
>               check_not_replaying 1
>               check_not_replaying 2
> @@ -128,7 +128,7 @@ proc test_cont {} {
>   
>   proc test_cont_all {} {
>       with_test_prefix "cont-all" {
> -        gdb_test "continue" "No more reverse-execution history.*"
> +        gdb_test "continue" "Reached end of recorded history.*"
>   
>           # this works because we're lock-stepping threads that executed exactly
>           # the same code starting from the same instruction.
> diff --git a/gdb/testsuite/gdb.btrace/nohist.exp b/gdb/testsuite/gdb.btrace/nohist.exp
> index d71909181c4..ac6a41c63e4 100644
> --- a/gdb/testsuite/gdb.btrace/nohist.exp
> +++ b/gdb/testsuite/gdb.btrace/nohist.exp
> @@ -42,7 +42,7 @@ with_test_prefix "forward" {
>       check_not_replaying
>   }
>   
> -gdb_test "reverse-continue" "No more reverse-execution history\.\r\n.*"
> +gdb_test "reverse-continue" "Reached end of recorded history; stopping.*"
>   
>   with_test_prefix "backward" {
>       check_not_replaying
> diff --git a/gdb/testsuite/gdb.btrace/non-stop.exp b/gdb/testsuite/gdb.btrace/non-stop.exp
> index 62c940e4cd6..5e43545f6a9 100644
> --- a/gdb/testsuite/gdb.btrace/non-stop.exp
> +++ b/gdb/testsuite/gdb.btrace/non-stop.exp
> @@ -79,16 +79,26 @@ 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\." \
> +             "Reached end of recorded.*Backward execution.*" \
>                "\[^\\\r\\\n\]*" \
>                "\[^\\\r\\\n\]*" \
>               ] \
>           $nthreads
>   }
>   
> +proc gdb_cont_to_no_history_forward { threads cmd nthreads } {
> +    gdb_cont_to $threads $cmd \
> +	[multi_line \
> +	     "Reached end of recorded.*Following forward.*" \
> +	     "\[^\\\r\\\n\]*" \
> +	     "\[^\\\r\\\n\]*" \
> +	    ] \
> +	$nthreads
> +}
> +
>   # trace the code between the two breakpoints
>   with_test_prefix "prepare" {
>       gdb_cont_to_bp_line "$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.btrace/stepi.exp b/gdb/testsuite/gdb.btrace/stepi.exp
> index a70a5adf046..689bc792b24 100644
> --- a/gdb/testsuite/gdb.btrace/stepi.exp
> +++ b/gdb/testsuite/gdb.btrace/stepi.exp
> @@ -100,7 +100,7 @@ with_test_prefix "reverse-nexti.1" {
>   # we can't reverse-nexti any further
>   with_test_prefix "reverse-nexti.2" {
>       gdb_test "reverse-nexti" \
> -	"No more reverse-execution history\.\r\n.*main\.2.*" \
> +	"Reached end of recorded history; stopping\.\r\n.*main\.2.*" \
>   	"reverse-nexti.2"
>       check_replay_at 1
>   }
> @@ -140,20 +140,20 @@ with_test_prefix "goto begin" {
>   
>       with_test_prefix "reverse-stepi" {
>   	gdb_test "reverse-stepi" \
> -	    "No more reverse-execution history\.\r\n.*main\.2.*" \
> +	    "Reached end of recorded history; stopping\.\r\n.*main\.2.*" \
>   	    "reverse-stepi.1"
>   	gdb_test "reverse-stepi" \
> -	    "No more reverse-execution history\.\r\n.*main\.2.*" \
> +	    "Reached end of recorded history; stopping\.\r\n.*main\.2.*" \
>   	    "reverse-stepi.2"
>   	check_replay_at 1
>       }
>   
>       with_test_prefix "reverse-nexti" {
>   	gdb_test "reverse-nexti" \
> -	    "No more reverse-execution history\.\r\n.*main\.2.*" \
> +	    "Reached end of recorded history; stopping\.\r\n.*main\.2.*" \
>   	    "reverse-nexti.1"
>   	gdb_test "reverse-nexti" \
> -	    "No more reverse-execution history\.\r\n.*main\.2.*" \
> +	    "Reached end of recorded history; stopping\.\r\n.*main\.2.*" \
>   	    "reverse-nexti.2"
>   	check_replay_at 1
>       }
> @@ -169,10 +169,10 @@ with_test_prefix "goto begin" {
>   with_test_prefix "reverse-stepi" {
>       gdb_test "reverse-stepi" ".*main\.2.*" "reverse-stepi.1"
>       gdb_test "reverse-stepi" \
> -	"No more reverse-execution history\.\r\n.*main\.2.*" \
> +	"Reached end of recorded history; stopping\.\r\n.*main\.2.*" \
>   	"reverse-stepi.2"
>       gdb_test "reverse-stepi" \
> -	"No more reverse-execution history\.\r\n.*main\.2.*" \
> +	"Reached end of recorded history; stopping\.\r\n.*main\.2.*" \
>   	"reverse-stepi.3"
>       check_replay_at 1
>   }
> diff --git a/gdb/testsuite/gdb.reverse/break-precsave.exp b/gdb/testsuite/gdb.reverse/break-precsave.exp
> index b9d94681247..6d9b312185f 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 -wrap "Reached end of recorded.*Following forward.* end of main .*" {
>   	    pass "go to end of main forward"
>   	}
>       }
> @@ -87,7 +87,7 @@ proc precsave_tests {} {
>   	-re ".*Breakpoint $decimal,.*$srcfile:$main_location.*$gdb_prompt $" {
>   	    pass "main backward"
>   	}
> -	-re "No more reverse-execution history.* break in main .*$gdb_prompt $" {
> +	-re -wrap "Reached end of recorded.*Backward execution.* break in main .*" {
>   	    pass "main backward"
>   	}
>       }
> @@ -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 -wrap "Reached end of recorded.*Following forward.* end of main .*" {
>   	    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..66e9712707f 100644
> --- a/gdb/testsuite/gdb.reverse/break-reverse.exp
> +++ b/gdb/testsuite/gdb.reverse/break-reverse.exp
> @@ -64,7 +64,7 @@ gdb_test_multiple "continue" "main backward" {
>       -re ".*Breakpoint $decimal,.*$srcfile:$main_location.*$gdb_prompt $" {
>   	pass "main backward"
>       }
> -    -re "No more reverse-execution history.* break in main .*$gdb_prompt $" {
> +    -re -wrap "Reached end of recorded history.*Backward execution.*" {
>   	pass "main backward"
>       }
>   }
> @@ -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 -wrap "Reached end of recorded history.*Following forward.*" {
>   	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..cedca0f9b65 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 $" {
> +    -re -wrap "Reached end of recorded history.*Following forward.*" {
>   	pass "go to end of main forward"
>       }
>   }
> diff --git a/gdb/testsuite/gdb.reverse/sigall-precsave.exp b/gdb/testsuite/gdb.reverse/sigall-precsave.exp
> index e5890ad7af7..aab4551c874 100644
> --- a/gdb/testsuite/gdb.reverse/sigall-precsave.exp
> +++ b/gdb/testsuite/gdb.reverse/sigall-precsave.exp
> @@ -128,7 +128,7 @@ proc test_one_sig_reverse {prevsig} {
>   		xfail "$testmsg (handled)"
>   	    }
>   	}
> -	-re "No more reverse-execution history.*kill.*$gdb_prompt " {
> +	-re "Reached end of recorded history.*Backward execution.*kill.*$gdb_prompt " {
>   	    if {$saw_signal} {
>   		pass "$testmsg (handled)"
>   	    } else {
> diff --git a/gdb/testsuite/gdb.reverse/sigall-reverse.exp b/gdb/testsuite/gdb.reverse/sigall-reverse.exp
> index f2cf55b8ae4..884b178f9ee 100644
> --- a/gdb/testsuite/gdb.reverse/sigall-reverse.exp
> +++ b/gdb/testsuite/gdb.reverse/sigall-reverse.exp
> @@ -134,7 +134,7 @@ proc test_one_sig_reverse {prevsig} {
>   		xfail "$testmsg (handled)"
>   	    }
>   	}
> -	-re "No more reverse-execution history.*kill.*$gdb_prompt " {
> +	-re "Reached end of recorded.*Backward execution.*kill.*$gdb_prompt " {
>   	    if {$saw_signal} {
>   		pass "$testmsg (handled)"
>   	    } else {
> diff --git a/gdb/testsuite/gdb.reverse/singlejmp-reverse.exp b/gdb/testsuite/gdb.reverse/singlejmp-reverse.exp
> index 971d88b5ce6..73923564514 100644
> --- a/gdb/testsuite/gdb.reverse/singlejmp-reverse.exp
> +++ b/gdb/testsuite/gdb.reverse/singlejmp-reverse.exp
> @@ -50,11 +50,13 @@ gdb_test "next" {nodebug \(\);} "next to nodebug"
>   gdb_test "next" {v = 3;} "next to v = 3"
>   
>   # FAIL was:
> -# No more reverse-execution history.
> +# Reached end of recorded history; stopping.
> +# Backward execution from here not possible.
>   # {
>   gdb_test "reverse-step" {nodebug \(\);}
>   
>   # FAIL was:
> -# No more reverse-execution history.
> +# Reached end of recorded history; stopping.
> +# Backward execution from here not possible.
>   # {
>   gdb_test "reverse-next" {f \(\);}


-- 
Cheers,
Guinevere Larsen
She/Her/Hers