Re: libtool 2.4 args parsing incredibly slow

[Peter O'Gorman]

On 01/24/2011 07:05 PM, Dan McGee wrote:
> Hadn't noticed this regression until I was running some things on my
> slower Atom laptop today, but thought I'd let you guys know what we're
> seeing in our test suite. The project is pacman
> (http://projects.archlinux.org/pacman.git/), the Arch Linux package
> manager. I've tried to put together a small test case to show the
> difference; a tarball is attached. Extract it and copy your /bin/echo
> to .libs/lt-echo and it should work.
>
> I'm noticing the super slow argument parsing when invoking the wrapper
> script during our test runs. This particular test is meant to provide
> 1000 test packages as arguments; it performs fine on our maint branch
> but takes forever on master now due to a libtool upgrade.
>
> Here is the output of my test harness/script:

I am not really sure what to do about this, something like:

--- a/libltdl/config/ltmain.m4sh
+++ b/libltdl/config/ltmain.m4sh
@@ -3195,6 +3195,8 @@ func_exec_program_core ()
 # launches target application with the remaining arguments.
 func_exec_program ()
 {
+  case \${1+\"address@hidden"} in
+  *--lt*)
   for lt_wr_arg
   do
     case \$lt_wr_arg in
@@ -3202,7 +3204,8 @@ func_exec_program ()
     *) set x \"address@hidden" \"\$lt_wr_arg\"; shift;;
     esac
     shift
-  done
+  done ;;
+  esac
   func_exec_program_core \${1+\"address@hidden"}
 }


Will avoid the issue if argv doesn't match *--lt-* (surely the most 
common case).

Changing the loop to do something different would undoubtedly impact 
other shells, but that being said, it seems likely that bash is one of 
the most common shells used for running libtool wrapper scripts :(

Explicitly CCing Ralf for his thoughts.

Peter