Re: Speeding up libtool

[Ralf Wildenhues]

* Ralf Wildenhues wrote on Mon, Apr 04, 2005 at 09:06:25AM CEST:
> * Robert Ögren wrote on Mon, Apr 04, 2005 at 01:30:26AM CEST:
> >
> > With ash and lt_ECHO=printf...:

> > I think the disappointing speedup is caused by a lot of spawning of 
> > printf (printf isn't a builtin in ash, right?) Setting ECHO=echo in 
> > config.status makes it take 5.7 seconds after the patch (8.2 before).
> 
> ash's `echo' is bad for libtool, as it interprets backslashes by
> default.  The ash I use on linux has printf builtin.  I looked on
> cygwin.com, they seem to ship an older ash variant without printf
> builtin.  You may want to try a newer one or even try to get them to
> include it in cygwin proper. 

I checked a cygwin installation.  The /bin/sh had no builtin printf, but
its builtin echo does _not_ interpret backslashes, so it's actually
usable for libtool.

  CONFIG_SHELL=/bin/sh /bin/sh configure

should thus work.  Sorry for not checking earlier.

Meaning 40% speedup for config.status on cygwin.  :)
I get about 30% on linux/x86.

OK to apply to HEAD?

Regards,
Ralf

        * m4/libtool.m4 (_LT_CONFIG_COMMANDS): Only call sed if
        necessary while quoting all libtool variables.
        Reported by Robert Ögren <address@hidden>.

Index: m4/libtool.m4
===================================================================
RCS file: /cvsroot/libtool/libtool/m4/libtool.m4,v
retrieving revision 1.177
diff -u -r1.177 libtool.m4
--- m4/libtool.m4       28 Mar 2005 09:32:59 -0000      1.177
+++ m4/libtool.m4       28 Mar 2005 16:00:34 -0000
@@ -462,12 +462,26 @@
 
 # Quote evaled strings.
 for var in lt_decl_all_varnames([[ ]], lt_decl_quote_varnames); do
-    eval "lt_\$var=\\\\\\"\\\`\\\$ECHO \\"X\\\$\$var\\" | \\\$Xsed -e 
\\"\\\$sed_quote_subst\\"\\\`\\\\\\""
+    case \`eval \\\\\$ECHO "X\\\\\$\$var"\` in
+    *[[\\\\\\\`\\"\\\$]]*)
+      eval "lt_\$var=\\\\\\"\\\`\\\$ECHO \\"X\\\$\$var\\" | \\\$Xsed -e 
\\"\\\$sed_quote_subst\\"\\\`\\\\\\""
+      ;;
+    *)
+      eval "lt_\$var=\\\\\\"\\\$\$var\\\\\\""
+      ;;
+    esac
 done
 
 # Double-quote double-evaled strings.
 for var in lt_decl_all_varnames([[ ]], lt_decl_dquote_varnames); do
-    eval "lt_\$var=\\\\\\"\\\`\\\$ECHO \\"X\\\$\$var\\" | \\\$Xsed -e 
\\"\\\$double_quote_subst\\" -e \\"\\\$sed_quote_subst\\" -e 
\\"\\\$delay_variable_subst\\"\\\`\\\\\\""
+    case \`eval \\\\\$ECHO "X\\\\\$\$var"\` in
+    *[[\\\\\\\`\\"\\\$]]*)
+      eval "lt_\$var=\\\\\\"\\\`\\\$ECHO \\"X\\\$\$var\\" | \\\$Xsed -e 
\\"\\\$double_quote_subst\\" -e \\"\\\$sed_quote_subst\\" -e 
\\"\\\$delay_variable_subst\\"\\\`\\\\\\""
+      ;;
+    *)
+      eval "lt_\$var=\\\\\\"\\\$\$var\\\\\\""
+      ;;
+    esac
 done
 
 # Fix-up fallback echo if it was mangled by the above quoting rules.