RISC-V: Add configure option: --with-multilib-generator to flexible config multi-lib settings.

 - Able to configure complex multi-lib rule in configure time, without modify
   any in-tree source.

 - I was consider to implmenet this into `--with-multilib-list` option,
   but I am not sure who will using that with riscv*-*-elf*, so I decide to
   using another option name for that.

 - --with-multilib-generator will pass arguments to multilib-generator, and
   then using the generated multi-lib config file to build the toolchain.

   e.g. Build riscv gcc, default arch/abi is rv64gc/lp64, and build multilib
       for rv32imafd/ilp32 and rv32i/ilp32; rv32ic/ilp32 will reuse
       rv32i/ilp32.
    $ <GCC-SRC>/configure \
       --target=riscv64-elf \
       --with-arch=rv64gc --with-abi=lp64 \
       --with-multilib-generator=rv32i-ilp32--c;rv32imafd-ilp32--

V3 Changes:

 - Rename --with-multilib-config to --with-multilib-generator
 - Check --with-multilib-generator and --with-multilib-list can't be used at
   same time.

V2 Changes:

 - Fix --with-multilib-config hanling on non riscv*-*-elf* triple.

gcc/ChangeLog:

	* config.gcc (riscv*-*-*): Handle --with-multilib-generator.
	* configure: Regen.
	* configure.ac: Add --with-multilib-generator.
	* config/riscv/multilib-generator: Exit when parsing arch string error.
	* config/riscv/t-withmultilib-generator: New.
	* doc/install.texi: Document --with-multilib-generator.

1 files changed, 31 insertions, 5 deletions

diff --git a/gcc/config.gcc b/gcc/config.gcc
index b169f2f..dc6d68b 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -2438,11 +2438,13 @@ riscv*-*-elf* | riscv*-*-rtems*)
 	  tmake_file="${tmake_file} riscv/t-rtems"
 	  ;;
 	*)
-	  case "x${enable_multilib}" in
-	  xno) ;;
-	  xyes) tmake_file="${tmake_file} riscv/t-elf-multilib" ;;
-	  *) echo "Unknown value for enable_multilib"; exit 1
-	  esac
+	  if test "x${with_multilib_generator}" == xdefault; then
+		  case "x${enable_multilib}" in
+		  xno) ;;
+		  xyes) tmake_file="${tmake_file} riscv/t-elf-multilib" ;;
+		  *) echo "Unknown value for enable_multilib"; exit 1
+		  esac
+	  fi
 	esac
 	tmake_file="${tmake_file} riscv/t-riscv"
 	gnu_ld=yes
@@ -4609,6 +4611,30 @@ case "${target}" in
 			exit 1
 			;;
 		esac
+		# Handle --with-multilib-generator.
+		if test "x${with_multilib_generator}" != xdefault; then
+			if test "x${with_multilib_list}" != xdefault; then
+				echo "--with-multilib-list= can't used with --with-multilib-generator= at same time" 1>&2
+				exit 1
+			fi
+			case "${target}" in
+			riscv*-*-elf*)
+				if ${srcdir}/config/riscv/multilib-generator \
+					`echo ${with_multilib_generator} | sed 's/;/ /g'`\
+					> t-multilib-config;
+				then
+					tmake_file="${tmake_file} riscv/t-withmultilib-generator"
+				else
+					echo "invalid option for --with-multilib-generator" 1>&2
+					exit 1
+				fi
+				;;
+			*)
+				echo "--with-multilib-generator= is not supported for ${target}, only supported for riscv*-*-elf*" 1>&2
+				exit 1
+				;;
+			esac
+		fi
 
 		# Handle --with-multilib-list.
 		if test "x${with_multilib_list}" != xdefault; then