[RFC][gdb/testsuite] Add -lbl option in gdb_test_multiple

[Tom de Vries <tdevries at suse dot de>]

[ was: Re: [RFC][gdb/testsuite] Handle -line and -non-empty-line in
gdb_test_multiple ]
On 20-02-2020 14:27, Pedro Alves wrote:
> On 2/19/20 9:30 PM, Tom de Vries wrote:
>> [ was: Re: [PATCH][gdb/testsuite] Fix corefile-buildid.exp with
> 
>> Committed.
>>
>>> If this pattern appears in more places it may be worth it to
>>> think about some abstraction to make it easier to write.
>>> Like e.g., a new "-lbl" (line-by-line) option switch to
>>> gdb_test_multiple that auto-appends the "match one line" regexp.
>>
>> How about this?
> 
> Oh, by "pattern", I meant the design pattern, the higher-level
> thing of expecting a string while at the same time consuming
> input a line at a time.

Right, I sort of got that, but went for a simpler form of abstraction.

> Something like:
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~
> diff --git c/gdb/testsuite/lib/gdb.exp w/gdb/testsuite/lib/gdb.exp
> index d8ebddf63ce..6eaebc7710d 100644
> --- c/gdb/testsuite/lib/gdb.exp
> +++ w/gdb/testsuite/lib/gdb.exp
> @@ -858,6 +858,7 @@ proc gdb_test_multiple { command message user_code { prompt_regexp "" } } {
>      set expecting_action 0
>      set expecting_arg 0
>      set wrap_pattern 0
> +    set line_by_line 0
>      foreach item $user_code subst_item $subst_code {
>         if { $item == "-n" || $item == "-notransfer" || $item == "-nocase" } {
>             lappend $current_list $item
> @@ -880,6 +881,10 @@ proc gdb_test_multiple { command message user_code { prompt_regexp "" } } {
>             set wrap_pattern 1
>             continue
>         }
> +       if {$item == "-lbl"} {
> +           set line_by_line 1
> +           continue
> +       }
>         if { $expecting_arg } {
>             set expecting_arg 0
>             lappend $current_list $subst_item
> @@ -1070,6 +1075,14 @@ proc gdb_test_multiple { command message user_code { prompt_regexp "" } } {
>         }
>      }
>  
> +    if {$line_by_line} {
> +       append code {
> +           -re "^\[^\r\n\]*\r\n" {
> +               exp_continue
> +           }
> +       }
> +    }
> +
>      # Now patterns that apply to any spawn id specified.
>      append code {
>         -i $any_spawn_id
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> That should mean we could drop the $gdb_prompt matches too.
> But maybe a new gdb_test_lbl procedure that wraps gdb_test_multiple
> would be preferred.
> 

I think we don't want to integrate -lbl in the user_code parsing, because:
...
gdb_test_multiple "command" "testname" {
	-re "bla" {
	}
	-lbl
}
...
and:
...
gdb_test_multiple "command" "testname" {
	-lbl
	-re "bla" {
	}
}
...
will have the same effect, which is likely to cause confusion.

So I've added it as option to gdb_test_multiple. [ Which caused me to
rewrite the optional $prompt_regexp argument to -prompt $prompt_regexp. ]

I had to rewrite the -lbl regexp to "\r\n" at start-of-line rather than
end-of-line, because it didn't work well otherwise with the implicit
regexps that are listed before it.  Consequently, I had to rewrite the
regexps in corefile-buildid.exp in a similar way.

> The way you have it doesn't look very different from
> creating a couple globals, like:
> 
>  set line_re "^\[^\r\n\]*\r\n"
>  set non_empty_line_re "^\[^\r\n\]+\r\n"
> 
> and the using them like:
> 
>  -re "$line_re" {
> 
> Maybe removing the leading "^" anchor from the variables
> would make them usable in more places.
> 

Ack, that all makes sense.

> Anyway, I don't object to your patch if you like it.  It just
> wasn't what I was suggesting.

I'll drop that one for now, maybe rewrite it at some point to use some
global variables instead.

So how about this -lbl implementation? Any comments (other than missing
documentation in gdb_test_multiple proc header)?

Reg-tested on x86_64-linux.

Tested corefile-buildid.exp with check-read1.

Thanks,
- Tom

[gdb/testsuite] Add -lbl option in gdb_test_multiple

Add gdb_test_multiple option -lbl, that adds a regexp after the user code that
reads one line, and discards it:
...
           -re "\r\n\[^\r\n\]*(?=\r\n)" {
               exp_continue
           }
...

In order to be able to write:
...
gdb_test_multiple "command" "testname" {
  ...
} -lbl
...
as opposed to having to insert the "" for the prompt_regexp arguments:
...
gdb_test_multiple "command" "testname" {
  ...
} "" -lbl
...
rewrite the promp_regexp argument usage into:
...
gdb_test_multiple "command" "testname" {
  ...
} -prompt $prompt_regexp
...

gdb/testsuite/ChangeLog:

2020-02-2120  Pedro Alves  <palves@redhat.com>
	      Tom de Vries  <tdevries@suse.de>

	* lib/gdb.exp (gdb_test_multiple): Handle prompt_regexp option using
	-prompt prefix.  Add -lbl option.
	(skip_python_tests_prompt, skip_libstdcxx_probe_tests_prompt)
	(gdb_is_target_1): Add -prompt prefix.
	* gdb.base/corefile-buildid.exp: Use -lbl option.  Rewrite regexps to
	have "\r\n" at start-of-line, instead of at end-of-line.

---
 gdb/testsuite/gdb.base/corefile-buildid.exp | 27 ++++++--------------------
 gdb/testsuite/lib/gdb.exp                   | 30 ++++++++++++++++++++++++-----
 2 files changed, 31 insertions(+), 26 deletions(-)

diff --git a/gdb/testsuite/gdb.base/corefile-buildid.exp b/gdb/testsuite/gdb.base/corefile-buildid.exp
index b9844ee354..b91550bc82 100644
--- a/gdb/testsuite/gdb.base/corefile-buildid.exp
+++ b/gdb/testsuite/gdb.base/corefile-buildid.exp
@@ -114,17 +114,11 @@ proc check_exec_file {file} {
     # Get line with "Local exec file:".
     set ok 0
     gdb_test_multiple "info files" "" {
-	-re "^Local exec file:\r\n" {
+	-re "\r\nLocal exec file:" {
 	    set test_name $gdb_test_name
 	    set ok 1
 	}
-	-re "^$gdb_prompt $" {
-	    fail $gdb_test_name
-	}
-	-re "^\[^\r\n\]*\r\n" {
-	    exp_continue
-	}
-    }
+    } -lbl
 
     if { $ok == 0 } {
 	return
@@ -133,16 +127,10 @@ proc check_exec_file {file} {
     # Get subsequent line with $file.
     set ok 0
     gdb_test_multiple "" $test_name {
-	-re "^\[\t\ \]+`[string_to_regexp $file]'\[^\r\n\]*\r\n" {
+	-re "\r\n\[\t\ \]+`[string_to_regexp $file]'\[^\r\n\]*" {
 	    set ok 1
 	}
-	-re "^$gdb_prompt $" {
-	    fail $gdb_test_name
-	}
-	-re "^\[^\r\n\]*\r\n" {
-	    exp_continue
-	}
-    }
+    } -lbl
 
     if { $ok == 0 } {
 	return
@@ -150,13 +138,10 @@ proc check_exec_file {file} {
 
     # Skip till prompt.
     gdb_test_multiple "" $test_name {
-	-re "^$gdb_prompt $" {
+	-re "\r\n$gdb_prompt $" {
 	    pass $gdb_test_name
 	}
-	-re "^\[^\r\n\]*\r\n" {
-	    exp_continue
-	}
-    }
+    } -lbl
 }
 
 # Test whether gdb can find an exec file from a core file's build-id.
diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 81518b9646..caa64f36f1 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -792,7 +792,7 @@ proc gdb_internal_error_resync {} {
 #	}
 #    }
 #
-proc gdb_test_multiple { command message user_code { prompt_regexp "" } } {
+proc gdb_test_multiple { command message user_code args } {
     global verbose use_gdb_stub
     global gdb_prompt pagination_prompt
     global GDB
@@ -802,6 +802,18 @@ proc gdb_test_multiple { command message user_code { prompt_regexp "" } } {
     upvar expect_out expect_out
     global any_spawn_id
 
+    set line_by_line 0
+    set prompt_regexp ""
+    for {set i 0} {$i < [llength $args]} {incr i} {
+	set opt [lindex $args $i]
+	if { $opt  == "-prompt" } {
+	    incr i
+	    set prompt_regexp [lindex $args $i]
+	} elseif { $opt == "-lbl" } {
+	    set line_by_line 1
+	}
+    }
+
     if { "$prompt_regexp" == "" } {
 	set prompt_regexp "$gdb_prompt $"
     }
@@ -1070,6 +1082,14 @@ proc gdb_test_multiple { command message user_code { prompt_regexp "" } } {
 	}
     }
 
+    if {$line_by_line} {
+       append code {
+           -re "\r\n\[^\r\n\]*(?=\r\n)" {
+               exp_continue
+           }
+       }
+    }
+
     # Now patterns that apply to any spawn id specified.
     append code {
 	-i $any_spawn_id
@@ -2005,7 +2025,7 @@ proc skip_python_tests_prompt { prompt_regexp } {
 	    return 1
 	}
 	-re "$prompt_regexp" {}
-    } "$prompt_regexp"
+    } -prompt "$prompt_regexp"
 
     gdb_test_multiple "python print (sys.version_info\[0\])" "check if python 3" {
 	-re "3.*$prompt_regexp" {
@@ -2014,7 +2034,7 @@ proc skip_python_tests_prompt { prompt_regexp } {
 	-re ".*$prompt_regexp" {
             set gdb_py_is_py3k 0
         }
-    } "$prompt_regexp"
+    } -prompt "$prompt_regexp"
 
     return 0
 }
@@ -3274,7 +3294,7 @@ proc skip_libstdcxx_probe_tests_prompt { prompt_regexp } {
 	}
 	-re "\r\n$prompt_regexp" {
 	}
-    } "$prompt_regexp"
+    } -prompt "$prompt_regexp"
     set skip [expr !$supported]
     return $skip
 }
@@ -3322,7 +3342,7 @@ proc gdb_is_target_1 { target_name target_stack_regexp prompt_regexp } {
 	-re "$prompt_regexp" {
 	    pass $test
 	}
-    } "$prompt_regexp"
+    } -prompt "$prompt_regexp"
     return 0
 }