Tackling long standing issues with startup.

anyone can offer any reason why it's not (long past) time to do this I
can back the truck up. (But I will have a list of bourne shell scripts
for you to write.)

With this commit:

1) -J options are now passed to the underlying JVM, along with -D
options which already were. scala -Dfoo=bar and scala -J-Dfoo=bar are
identical (but -J can pass arbitrary arguments to the jvm: -J-verbose,
-J-Xmx4G, etc.)

2) Eliminated DefinesSetting. It was ill-conceived because setting
system properties must be done at JVM start to guarantee they will be
seen where appropriate: by the time scala is involved it's too late. The
starter script takes care of routing -D to the jvm, and no longer sends
them along to scala as well. Since we have a new system package you can
read any property in system.props, like this:

% scala -Dp1="hi" -Dp2="bye" -e 'println(system.props filterKeys
(_.length == 2))' Map(p2 -> bye, p1 -> hi)

3) After measuring that startup is a full second faster by putting
the scala jars on the bootclasspath, I gave us a standard way to
take advantage of this. It's not done by default, although we should
seriously consider it (I'm familiar with the issues that have arisen in
the past.) Reclaim your life, one startup second at a time.

The flag is --usebootcp, as below:

// Here's a way (in bash 4) to compare repl startup times each way while
true ; do time pscala -i <(echo "system exit 0") ; done |& grep real
while true ; do time pscala --usebootcp -i <(echo "system exit 0") ;
done |& grep real

Once again I find myself unable to nominate any plausible reviewer (if
there were anyone interested in this stuff, they'd be doing it instead
of me) so no review.

1 files changed, 33 insertions, 10 deletions

diff --git a/src/compiler/scala/tools/ant/templates/tool-unix.tmpl b/src/compiler/scala/tools/ant/templates/tool-unix.tmpl
index ceb6ec5ad4..25616c171a 100644
--- a/src/compiler/scala/tools/ant/templates/tool-unix.tmpl
+++ b/src/compiler/scala/tools/ant/templates/tool-unix.tmpl
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 #
 ##############################################################################
 # Copyright 2002-2010, LAMP/EPFL
@@ -63,21 +63,44 @@ fi
 # Reminder: substitution ${JAVA_OPTS:=-Xmx256M -Xms16M} DO NOT work on Solaris
 [ -n "$JAVA_OPTS" ] || JAVA_OPTS="@javaflags@"
 
-# break out -D options and add them to JAVA_OPTS as well so they reach the
-# underlying JVM in time to do some good.
-for i
-do
-  case "$i" in
+# break out -D and -J options and add them to JAVA_OPTS as well
+# so they reach the underlying JVM in time to do some good.  The
+# -D options will be available as system properties.
+declare -a java_args
+declare -a scala_args
+CPSWITCH="-cp \"$TOOL_CLASSPATH\""
+
+while [ $# -gt 0 ]; do
+  case "$1" in
     -D*)
-      JAVA_OPTS="$JAVA_OPTS $i" ;;
+      java_args=("${java_args[@@]}" "$1")
+      shift
+      ;;
+    -J*)
+      java_args=("${java_args[@@]}" "${1:2}")
+      shift
+      ;;
+    --usebootcp)
+      CPSWITCH="-Xbootclasspath/a:\"$TOOL_CLASSPATH\""
+      shift
+      ;;
     *)
+      scala_args=("${scala_args[@@]}" "$1")
+      shift
       ;;
   esac
-done 
-
+done
+# reset "$@@" to the remaining args
+set -- "${scala_args[@@]}"
 
 if [ -z "$JAVACMD" -a -n "$JAVA_HOME" -a -x "$JAVA_HOME/bin/java" ]; then
     JAVACMD="$JAVA_HOME/bin/java"
 fi
 
-exec "${JAVACMD:=java}" $JAVA_OPTS -cp "$TOOL_CLASSPATH" -Dscala.usejavacp=true -Dscala.home="$SCALA_HOME" -Denv.emacs="$EMACS" @properties@ @class@ @toolflags@ "$@@"
+exec "${JAVACMD:=java}" \
+  "${java_args[@@]}" \
+  $CPSWITCH \
+  -Dscala.usejavacp=true \
+  -Dscala.home="$SCALA_HOME" \
+  -Denv.emacs="$EMACS" \
+  @properties@ @class@ @toolflags@ "$@@"