[PATCHv2] Fix setting breakpoints or stepping on line 65535

[Bernd Edlinger <bernd.edlinger@hotmail.de>]

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Hi Andrew,

On 12/1/19 11:08 PM, Andrew Burgess wrote:
> * Bernd Edlinger <bernd.edlinger@hotmail.de> [2019-11-24 11:54:23 +0000]:
> 
>> Hi,
>>
>> this removes code that is present from the very first git revisison
>> 7b4ac7e1ed2c4616bce56d1760807798be87ac9e from 1988.  It was in the
>> gdb/dbxread.c at the time (and makes more sense for dbx line info format
>> since line numbers are 16-bit entities in that debug format and debugging
>> files with more than 65535 lines would not work anyway) but moved from
>> there to gdb/buildsym.c which is used for dwarf line info as well, and
>> excluding an arbitrary line number does certainly not make sense nowadays.
>>
>>
>> Thanks
>> Bernd.
> 
>> From f202ae765b72ad6d17600eb661993a63191309f7 Mon Sep 17 00:00:00 2001
>> From: Bernd Edlinger <bernd.edlinger@hotmail.de>
>> Date: Sat, 23 Nov 2019 07:37:26 +0100
>> Subject: [PATCH 1/2] Fix setting breakpoints or stepping on line 65535
>>
> 
> Bernd,
> 
> Thanks for looking into this, and especially thanks for adding a test!
> 
> Normally you should include the git commit message and ChangeLog along
> with your patch submission so that these can be reviewed too. 'git
> format-patch' and 'git send-email' can be useful for this, if you can
> get them setup.
> 

Okay, I added changelog messages for gdb/ChangeLog and gdb/testsuite/ChangeLog,
and improved the commit messages.
I hope you can handle the format-patch files as attachments. 

> Given the age of the code you're removing I think this change sounds
> reasonable.  I assume there's no test that covers why this code should
> be there, so you see no regressions with this code removed?
> 

No, there were no regressions (last full test on 24-11-19).

> I have a couple of minor issues with the test.  If you address those
> and repost with commit message and ChangeLog this can be approved.
> 

Fixed the test.

Thanks a lot for your review.
Is it OK for trunk?


Thanks
Bernd.

> Thanks,
> Andrew
> 
> 
> 
> 
>> ---
>>  gdb/buildsym.c | 6 ------
>>  1 file changed, 6 deletions(-)
>>
>> diff --git a/gdb/buildsym.c b/gdb/buildsym.c
>> index 79f8305..6c14f3f 100644
>> --- a/gdb/buildsym.c
>> +++ b/gdb/buildsym.c
>> @@ -670,12 +670,6 @@ buildsym_compunit::record_line (struct subfile *subfile, int line,
>>  {
>>    struct linetable_entry *e;
>>  
>> -  /* Ignore the dummy line number in libg.o */
>> -  if (line == 0xffff)
>> -    {
>> -      return;
>> -    }
>> -
>>    /* Make sure line vector exists and is big enough.  */
>>    if (!subfile->line_vector)
>>      {
>> -- 
>> 1.9.1
>>
> 
>> From 54a7631206a2cf54573fb4cc94474cb2f6f99245 Mon Sep 17 00:00:00 2001
>> From: Bernd Edlinger <bernd.edlinger@hotmail.de>
>> Date: Sun, 24 Nov 2019 09:37:22 +0100
>> Subject: [PATCH 2/2] Add a test case for line 65535
>>
>> ---
>>  gdb/testsuite/gdb.base/line65535.c   | 19 +++++++++++++++++++
>>  gdb/testsuite/gdb.base/line65535.exp | 26 ++++++++++++++++++++++++++
>>  2 files changed, 45 insertions(+)
>>  create mode 100644 gdb/testsuite/gdb.base/line65535.c
>>  create mode 100644 gdb/testsuite/gdb.base/line65535.exp
>>
>> diff --git a/gdb/testsuite/gdb.base/line65535.c b/gdb/testsuite/gdb.base/line65535.c
>> new file mode 100644
>> index 0000000..d80a294
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.base/line65535.c
>> @@ -0,0 +1,19 @@
>> +/* This testcase is part of GDB, the GNU debugger.
>> +
>> +   Copyright 2019 Free Software Foundation, Inc.
>> +
>> +   This program is free software; you can redistribute it and/or modify
>> +   it under the terms of the GNU General Public License as published by
>> +   the Free Software Foundation; either version 3 of the License, or
>> +   (at your option) any later version.
>> +
>> +   This program is distributed in the hope that it will be useful,
>> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> +   GNU General Public License for more details.
>> +
>> +   You should have received a copy of the GNU General Public License
>> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
>> +
>> +#line 65535 "line65535.c"
>> +int main() { return 0; }
>> diff --git a/gdb/testsuite/gdb.base/line65535.exp b/gdb/testsuite/gdb.base/line65535.exp
>> new file mode 100644
>> index 0000000..2535ba5
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.base/line65535.exp
>> @@ -0,0 +1,26 @@
>> +# Copyright 2019 Free Software Foundation, Inc.
>> +
>> +# This program is free software; you can redistribute it and/or modify
>> +# it under the terms of the GNU General Public License as published by
>> +# the Free Software Foundation; either version 3 of the License, or
>> +# (at your option) any later version.
>> +#
>> +# This program is distributed in the hope that it will be useful,
>> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
>> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> +# GNU General Public License for more details.
>> +#
>> +# You should have received a copy of the GNU General Public License
>> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
>> +
> 
> Normally we like to add a short description of what the test is doing
> here - for new tests.  Many old ones don't have this thought.
> 

Okay, done.

>> +standard_testfile
>> +
>> +if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
>> +    return -1
>> +}
>> +
>> +gdb_test "break $srcfile:65535" \
>> +         ".*Breakpoint 1 at .*: file $srcfile, line 65535\\..*" \
>> +	 "break at line 65535"
>> +
>> +return 0
> 
> I don't think this return is needed at the end of a test.
> 

Okay, done.  Works without.

>> -- 
>> 1.9.1
>>
> 

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gdb:
2019-12-02  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	* buildsym.c (buildsym_compunit::record_line): Do no longer ignore
	line 65535.

gdb/testsuite:
2019-12-02  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	* gdb.base/line65535.exp: New file.
	* gdb.base/line65535.c: New file.


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From 7cee9fbe408af0a2da8e7812c2f86d2b9e4a809e Mon Sep 17 00:00:00 2001
From: Bernd Edlinger <bernd.edlinger@hotmail.de>
Date: Sat, 23 Nov 2019 07:37:26 +0100
Subject: [PATCH 1/2] Fix setting breakpoints or stepping on line 65535

This removes code that was present from the very first git revisison
7b4ac7e1ed2c4616bce56d1760807798be87ac9e from 1988.  It was in the
gdb/dbxread.c at the time (and makes more sense for dbx line info format
since line numbers are 16-bit entities in that debug format and debugging
files with more than 65535 lines would not work anyway) but moved from
there to gdb/buildsym.c which is used for dwarf line info as well, and
excluding an arbitrary line number does certainly not make sense nowadays.
---
 gdb/buildsym.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/gdb/buildsym.c b/gdb/buildsym.c
index 79f8305..6c14f3f 100644
--- a/gdb/buildsym.c
+++ b/gdb/buildsym.c
@@ -670,12 +670,6 @@ buildsym_compunit::record_line (struct subfile *subfile, int line,
 {
   struct linetable_entry *e;
 
-  /* Ignore the dummy line number in libg.o */
-  if (line == 0xffff)
-    {
-      return;
-    }
-
   /* Make sure line vector exists and is big enough.  */
   if (!subfile->line_vector)
     {
-- 
1.9.1


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From 46fe1ccfb2a1df701cb3bfeb6f882ca49f11ec0f Mon Sep 17 00:00:00 2001
From: Bernd Edlinger <bernd.edlinger@hotmail.de>
Date: Sun, 24 Nov 2019 09:37:22 +0100
Subject: [PATCH 2/2] Add a test case for line 65535

This adds a test case for setting a breakpoint on line 65535.
---
 gdb/testsuite/gdb.base/line65535.c   | 19 +++++++++++++++++++
 gdb/testsuite/gdb.base/line65535.exp | 28 ++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 gdb/testsuite/gdb.base/line65535.c
 create mode 100644 gdb/testsuite/gdb.base/line65535.exp

diff --git a/gdb/testsuite/gdb.base/line65535.c b/gdb/testsuite/gdb.base/line65535.c
new file mode 100644
index 0000000..d80a294
--- /dev/null
+++ b/gdb/testsuite/gdb.base/line65535.c
@@ -0,0 +1,19 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2019 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#line 65535 "line65535.c"
+int main() { return 0; }
diff --git a/gdb/testsuite/gdb.base/line65535.exp b/gdb/testsuite/gdb.base/line65535.exp
new file mode 100644
index 0000000..095f151
--- /dev/null
+++ b/gdb/testsuite/gdb.base/line65535.exp
@@ -0,0 +1,28 @@
+# Copyright 2019 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This test tries to place a breakpoint on line 65535.
+# For the purpose of this test we are satisfied if the break
+# command succeeds, we will not try to actually run to that line.
+
+standard_testfile
+
+if {[prepare_for_testing "failed to prepare" $testfile $srcfile debug]} {
+    return -1
+}
+
+gdb_test "break $srcfile:65535" \
+         ".*Breakpoint 1 at .*: file $srcfile, line 65535\\..*" \
+	 "break at line 65535"
-- 
1.9.1