2013-01-13 Terry Guo <terry.guo@arm.com>

        * gcc/Makefile.in (s-mlib): New argument MULTILIB_REUSE.
        * gcc/doc/fragments.texi: Document MULTILIB_REUSE.
        * gcc/gcc.c (multilib_reuse): New internal spec.
        (set_multilib_dir): Also search multilib from multilib_reuse.
        * gcc/genmultilib (tmpmultilib3): Refactor code.
        (tmpmultilib4): Ditto.
        (multilib_reuse): New multilib argument.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@195134 138bc75d-0d04-0410-961f-82ee72b054a4

5 files changed, 173 insertions, 51 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index db65beabe38..c4706588ba7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2013-01-13  Terry Guo  <terry.guo@arm.com>
+
+	* gcc/Makefile.in (s-mlib): New argument MULTILIB_REUSE.
+	* gcc/doc/fragments.texi: Document MULTILIB_REUSE.
+	* gcc/gcc.c (multilib_reuse): New internal spec.
+	(set_multilib_dir): Also search multilib from multilib_reuse.
+	* gcc/genmultilib (tmpmultilib3): Refactor code.
+	(tmpmultilib4): Ditto.
+	(multilib_reuse): New multilib argument.
+
 2013-01-13  Richard Sandiford  <rdsandiford@googlemail.com>
 
 	* Makefile.in: Update copyright.
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 3b2cf3cc46a..55b4d2dbce9 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1828,10 +1828,12 @@ s-mlib: $(srcdir)/genmultilib Makefile
 	    "$(MULTILIB_OSDIRNAMES)" \
 	    "$(MULTILIB_REQUIRED)" \
 	    "$(MULTIARCH_DIRNAME)" \
+	    "$(MULTILIB_REUSE)" \
 	    "@enable_multilib@" \
 	    > tmp-mlib.h; \
 	else \
-	  $(SHELL) $(srcdir)/genmultilib '' '' '' '' '' '' '' '' "$(MULTIARCH_DIRNAME)" no \
+	  $(SHELL) $(srcdir)/genmultilib '' '' '' '' '' '' '' '' \
+	    "$(MULTIARCH_DIRNAME)" '' no \
 	    > tmp-mlib.h; \
 	fi
 	$(SHELL) $(srcdir)/../move-if-change tmp-mlib.h multilib.h
diff --git a/gcc/doc/fragments.texi b/gcc/doc/fragments.texi
index a108ab035ba..b9a0c34b690 100644
--- a/gcc/doc/fragments.texi
+++ b/gcc/doc/fragments.texi
@@ -148,6 +148,35 @@ The @code{MULTILIB_REQUIRED} can be used together with
 @code{MULTILIB_OPTIONS} will be filtered by @code{MULTILIB_EXCEPTIONS}
 and then by @code{MULTILIB_REQUIRED}.
 
+@findex MULTILIB_REUSE
+@item MULTILIB_REUSE
+Sometimes it is desirable to reuse one existing multilib for different
+sets of options.  Such kind of reuse can minimize the number of multilib
+variants.  And for some targets it is better to reuse an existing multilib
+than to fall back to default multilib when there is no corresponding multilib.
+This can be done by adding reuse rules to @code{MULTILIB_REUSE}.
+
+A reuse rule is comprised of two parts connected by equality sign.  The left part
+is option set used to build multilib and the right part is option set that will
+reuse this multilib.  The order of options in the left part matters and should be
+same with those specified in @code{MULTILIB_REQUIRED} or aligned with order in
+@code{MULTILIB_OPTIONS}.  There is no such limitation for options in right part
+as we don't build multilib from them.  But the equality sign in both parts should
+be replaced with period.
+
+The @code{MULTILIB_REUSE} is different from @code{MULTILIB_MATCHES} in that it
+sets up relations between two option sets rather than two options.  Here is an
+example to demo how we reuse libraries built in Thumb mode for applications built
+in ARM mode:
+@smallexample
+@code{MULTILIB_REUSE} = mthumb/march.armv7-r=marm/march.armv7-r
+@end smallexample
+
+Before the advent of @code{MULTILIB_REUSE}, GCC select multilib by comparing command
+line options with options used to build multilib.  The @code{MULTILIB_REUSE} is
+complementary to that way.  Only when the original comparison matches nothing it will
+work to see if it is OK to reuse some existing multilib.
+
 @findex MULTILIB_EXTRA_OPTS
 @item MULTILIB_EXTRA_OPTS
 Sometimes it is desirable that when building multiple versions of
diff --git a/gcc/gcc.c b/gcc/gcc.c
index 8bdb6bc2303..ff0f5845224 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -855,6 +855,7 @@ static const char *multilib_select;
 static const char *multilib_matches;
 static const char *multilib_defaults;
 static const char *multilib_exclusions;
+static const char *multilib_reuse;
 
 /* Check whether a particular argument is a default argument.  */
 
@@ -1248,6 +1249,7 @@ static struct spec_list static_specs[] =
   INIT_STATIC_SPEC ("multilib_matches",		&multilib_matches),
   INIT_STATIC_SPEC ("multilib_exclusions",	&multilib_exclusions),
   INIT_STATIC_SPEC ("multilib_options",		&multilib_options),
+  INIT_STATIC_SPEC ("multilib_reuse",		&multilib_reuse),
   INIT_STATIC_SPEC ("linker",			&linker_name_spec),
   INIT_STATIC_SPEC ("linker_plugin_file",	&linker_plugin_file_spec),
   INIT_STATIC_SPEC ("lto_wrapper",		&lto_wrapper_spec),
@@ -6323,6 +6325,13 @@ main (int argc, char **argv)
     obstack_1grow (&multilib_obstack, 0);
     multilib_exclusions = XOBFINISH (&multilib_obstack, const char *);
 
+    q = multilib_reuse_raw;
+    while ((p = *q++) != (char *) 0)
+      obstack_grow (&multilib_obstack, p, strlen (p));
+
+    obstack_1grow (&multilib_obstack, 0);
+    multilib_reuse = XOBFINISH (&multilib_obstack, const char *);
+
     need_space = FALSE;
     for (i = 0; i < ARRAY_SIZE (multilib_defaults_raw); i++)
       {
@@ -7536,6 +7545,12 @@ set_multilib_dir (void)
 
   first = 1;
   p = multilib_select;
+
+  /* Append multilib reuse rules if any.  With those rules, we can reuse
+     one multilib for certain different options sets.  */
+  if (strlen (multilib_reuse) > 0)
+    p = concat (p, multilib_reuse, NULL);
+
   while (*p != '\0')
     {
       /* Ignore newlines.  */
@@ -7552,8 +7567,8 @@ set_multilib_dir (void)
 	  if (*p == '\0')
 	    {
 	    invalid_select:
-	      fatal_error ("multilib select %qs is invalid",
-			   multilib_select);
+	      fatal_error ("multilib select %qs %qs is invalid",
+			   multilib_select, multilib_reuse);
 	    }
 	  ++p;
 	}
diff --git a/gcc/genmultilib b/gcc/genmultilib
index 5afc6b53291..4dca65d68ff 100644
--- a/gcc/genmultilib
+++ b/gcc/genmultilib
@@ -85,6 +85,9 @@
 
 # The optional ninth argument is the multiarch name.
 
+# The optional tenth argument specifies how to reuse multilib for different
+# option sets.
+
 # The last option should be "yes" if multilibs are enabled.  If it is not
 # "yes", all GCC multilib dir names will be ".".
 
@@ -105,7 +108,7 @@
 #   genmultilib 'm64/m32 mno-app-regs|mcmodel=medany' '64 32 alt'
 #		'mcmodel?medany=mcmodel?medmid' 'm32/mno-app-regs* m32/mcmodel=*'
 #		'' 'm32/!m64/mno-app-regs m32/!m64/mcmodel=medany'
-#		'../lib64 ../lib32 alt' '' yes
+#		'../lib64 ../lib32 alt' '' '' '' yes
 # This produces:
 #   ". !m64 !m32 !mno-app-regs !mcmodel=medany;",
 #   "64:../lib64 m64 !m32 !mno-app-regs !mcmodel=medany;",
@@ -135,7 +138,8 @@ exclusions=$6
 osdirnames=$7
 multilib_required=$8
 multiarch=$9
-enable_multilib=${10}
+multilib_reuse=${10}
+enable_multilib=${11}
 
 echo "static const char *const multilib_raw[] = {"
 
@@ -349,61 +353,94 @@ done
 optout=`echo ${optout} | sed -e 's/^ //'`
 echo "\".${defaultosdirname} ${optout};\","
 
+# This part of code convert an option combination to
+# its corresponding directory names.
+# The directory names will be deduced from MULTILIB_DIRNAMES,
+# MULTILIB_OSDIRNAMES or the option combination itself.
+rm -rf tmpmultilib3
+cat >tmpmultilib3 <<\EOF
+#!/bin/sh
+
+dirout=
+combo=$1
+todirnames=$2
+toosdirnames=$3
+enable_multilib=$4
+
+if [ -n "${todirnames}" ]; then
+  dirout=`echo ${combo} | sed ${todirnames}`
+else
+  dirout=`echo ${combo} | sed -e 's/=/-/g'`
+fi
+# Remove the leading and trailing slashes.
+dirout=`echo ${dirout} | sed -e 's|^/||' -e 's|/*:/*|:|' -e 's|/$||g'`
+
+# Use the OS directory names rather than the option names.
+if [ -n "${toosdirnames}" ]; then
+  osdirout=`echo ${combo} | sed ${toosdirnames}`
+  # Remove the leading and trailing slashes.
+  osdirout=`echo ${osdirout} | sed -e 's|^/||' -e 's|/*:/*|:|' -e 's|/$||g'`
+  if [ "x${enable_multilib}" != xyes ]; then
+    dirout=".:${osdirout}"
+    disable_multilib=yes
+  else
+    case "${osdirout}" in
+      !*)
+	dirout=`echo ${osdirout} | sed 's/^!//'`
+	;;
+       *)
+	dirout="${dirout}:${osdirout}"
+	;;
+    esac
+  fi
+else
+  if [ "x${enable_multilib}" != xyes ]; then
+    # genmultilib with --disable-multilib should be
+    # called with '' '' '' '' '' '' '' no
+    # if MULTILIB_OSDIRNAMES is empty.
+    exit 1
+  fi
+fi
+echo "${dirout}"
+EOF
+chmod +x tmpmultilib3
+
+# Script to look through the options and output each option that is present,
+# and negate each option that is not present.
+rm -rf tmpmultilib4
+cat > tmpmultilib4 <<\EOF
+#!/bin/sh
+
+optout=
+combo=$1
+options=$2
+
+for set in ${options}; do
+  setopts=`echo ${set} | sed -e 's_[/|]_ _g'`
+  for opt in ${setopts}; do
+    if expr "${combo} " : ".*/${opt}/.*" > /dev/null; then
+      optout="${optout} ${opt}"
+    else
+      optout="${optout} !${opt}"
+    fi
+  done
+done
+optout=`echo ${optout} | sed -e 's/^ //'`
+echo "${optout}"
+EOF
+chmod +x tmpmultilib4
+
 # Work over the list of combinations.  We have to translate each one
 # to use the directory names rather than the option names, we have to
 # include the information in matches, and we have to generate the
 # correct list of options and negations.
 for combo in ${combinations}; do
   # Use the directory names rather than the option names.
-  if [ -n "${todirnames}" ]; then
-    dirout=`echo ${combo} | sed ${todirnames}`
-  else
-    dirout=`echo ${combo} | sed -e 's/=/-/g'`
-  fi
-  # Remove the leading and trailing slashes.
-  dirout=`echo ${dirout} | sed -e 's|^/||' -e 's|/*:/*|:|' -e 's|/$||g'`
-
-  # Use the OS directory names rather than the option names.
-  if [ -n "${toosdirnames}" ]; then
-    osdirout=`echo ${combo} | sed ${toosdirnames}`
-    # Remove the leading and trailing slashes.
-    osdirout=`echo ${osdirout} | sed -e 's|^/||' -e 's|/*:/*|:|' -e 's|/$||g'`
-    if [ "x${enable_multilib}" != xyes ]; then
-      dirout=".:${osdirout}"
-      disable_multilib=yes
-    else
-      case "${osdirout}" in
-        !*)
-	  dirout=`echo ${osdirout} | sed 's/^!//'`
-	  ;;
-	*)
-	  dirout="${dirout}:${osdirout}"
-	  ;;
-      esac
-    fi
-  else
-    if [ "x${enable_multilib}" != xyes ]; then
-      # genmultilib with --disable-multilib should be
-      # called with '' '' '' '' '' '' '' no
-      # if MULTILIB_OSDIRNAMES is empty.
-      exit 1
-    fi
-  fi
+  dirout=`./tmpmultilib3 "${combo}" "${todirnames}" "${toosdirnames}" "${enable_multilib}"`
 
   # Look through the options.  We must output each option that is
   # present, and negate each option that is not present.
-  optout=
-  for set in ${options}; do
-    setopts=`echo ${set} | sed -e 's_[/|]_ _g'`
-    for opt in ${setopts}; do
-      if expr "${combo} " : ".*/${opt}/.*" > /dev/null; then
-	optout="${optout} ${opt}"
-      else
-	optout="${optout} !${opt}"
-      fi
-    done
-  done
-  optout=`echo ${optout} | sed -e 's/^ //'`
+  optout=`./tmpmultilib4 "${combo}" "${options}"`
 
   # Output the line with all appropriate matches.
   dirout="${dirout}" optout="${optout}" ./tmpmultilib2
@@ -413,6 +450,35 @@ done
 echo "NULL"
 echo "};"
 
+# Output rules used for multilib reuse.
+echo ""
+echo "static const char *const multilib_reuse_raw[] = {"
+for rrule in ${multilib_reuse}; do
+  # The left part of the rule are the options we used to build multilib.
+  # The right part of the rule are the options that can reuse this multilib.
+  combo=`echo ${rrule} | sed -e 's/=.*$//' -e 's/\./=/g'`
+  copts=`echo ${rrule} | sed -e 's/^.*=//' -e 's/\./=/g'`
+  # The variable ${combinations} are the option combinations we will build
+  # multilib from.  If the combination in the left part of reuse rule isn't
+  # in this variable, it means no multilib will be built for current reuse
+  # rule.  Thus the reuse purpose specified by current rule is meaningless.
+  if expr "${combinations} " : ".*/${combo}/.*" > /dev/null; then
+    combo="/${combo}/"
+    dirout=`./tmpmultilib3 "${combo}" "${todirnames}" "${toosdirnames}" "${enable_multilib}"`
+    copts="/${copts}/"
+    optout=`./tmpmultilib4 "${copts}" "${options}"`
+    # Output the line with all appropriate matches.
+    dirout="${dirout}" optout="${optout}" ./tmpmultilib2
+  else
+    echo "The rule ${rrule} is trying to reuse nonexistent multilib."
+    exit 1
+  fi
+done
+
+# Terminate the list of string.
+echo "NULL"
+echo "};"
+
 # Output all of the matches now as option and that is the same as that, with
 # a semicolon trailer.  Include all of the normal options as well.
 # Note, the format of the matches is reversed compared