Re: [PATCH] Don't munge yacc's #line directives

[Patrick Palka <patrick@parcs.ath.cx>]

[-- Attachment #1: Type: text/plain, Size: 1067 bytes --]

On Thu, Jan 8, 2015 at 9:06 AM, Pedro Alves <palves@redhat.com> wrote:
> On 01/08/2015 12:48 PM, Patrick Palka wrote:
>
>> Here is the upstream automake patch that is probably responsible for
>> making the sed expression in question obsolete:
>> http://git.savannah.gnu.org/cgit/automake.git/commit/lib/ylwrap?id=b6359a5f310160c8a4a2e8e8c0105408412ce400
>
> I find that a bit confusing, since the comment says:
>
>  # We don't want the resulting debug information to point at
>  # an absolute srcdir.
>
> (the upstream master version still has the comment, though
> reformatted).
>
> In any case, I think we've done due diligence already.
>
> Could you update the commit log with the new findings and
> references, and please also include an before/after example
> of a #line line?  With that, the patch is OK.
>
> E.g., here's what I see, before/after your patch:
>
>  -#line 36 "/home/pedro/gdb/mygit/src/gdb//home/pedro/gdb/mygit/src/gdb/ada-exp.y"
>  +#line 36 "/home/pedro/gdb/mygit/src/gdb/ada-exp.y"

Attached is what I committed.

>
> Thanks,
> Pedro Alves
>

[-- Attachment #2: 0001-Don-t-munge-yacc-s-line-directives.patch --]
[-- Type: application/octet-stream, Size: 2414 bytes --]

From 6bf045cd32d07ae55d7eec8ff94bd937c6bb2bce Mon Sep 17 00:00:00 2001
From: Patrick Palka <patrick@parcs.ath.cx>
Date: Sun, 30 Nov 2014 11:47:16 -0500
Subject: [PATCH] Don't munge yacc's #line directives

The #line directives within GDB's autogenerated yacc files (e.g.
c-exp.c) are being incorrectly munged, causing these directives to refer
to nonexistent source files, e.g.

 #line 36 "/home/patrick/binutils-gdb/gdb//home/patrick/binutils-gdb/gdb/c-exp.y"

as opposed to

  #line 36 "/home/patrick/binutils-gdb/gdb/c-exp.y"

The munging happens due to a sed expression added by commit 954d8cae
whose intended purpose[1] was to work around the fact that ylwrap emitted #line
directives without any directory information, e.g.

  #line 36 "c-exp.y"

So the sed expression was meant to munge such directives to refer to
absolute paths instead.  But the behavior of ylwrap was changed some
years ago[2] to emit absolute paths within #line directives.  And when
our local copy of ylwrap was synced by commit e30465112, the sed
expression in question became unnecessary, and indeed harmful.

This patch removes the now-obsolete sed expression.  The emitted #line
directives are now correct without it.

gdb/ChangeLog:

	* Makefile.in (.y.c): Don't munge yacc's #line
	directives.

[1]: https://sourceware.org/ml/gdb-patches/2010-11/msg00265.html
[2]: http://git.savannah.gnu.org/cgit/automake.git/commit/lib/ylwrap?id=b6359a5f3
---
 gdb/ChangeLog   | 5 +++++
 gdb/Makefile.in | 1 -
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 2e9816a..c830053 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2015-01-09  Patrick Palka  <patrick@parcs.ath.cx>
 
+	* Makefile.in (.y.c): Don't munge yacc's #line
+	directives.
+
+2015-01-09  Patrick Palka  <patrick@parcs.ath.cx>
+
 	* utils.c (defaulted_query): Rewrite to use gdb_readline_wrapper
 	to prompt for input.
 	* tui/tui-hooks.c (tui_query_hook): Remove.
diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 5dae3e6..86ab1be 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -1858,7 +1858,6 @@ po/$(PACKAGE).pot: force
 	     -e 's/\([ \t;,(]\)free\([ \t]*[&(),]\)/\1xfree\2/g' \
 	     -e 's/\([ \t;,(]\)free$$/\1xfree/g' \
 	     -e '/^#line.*y.tab.c/d' \
-	     -e "s/^\(#line.*\)`basename $<`/\1`echo $<|sed 's/\//\\\\\//g'`/" \
 	  < $@.tmp > $@
 	rm -f $@.tmp
 .l.c:
-- 
2.2.1.212.gc5b9256