RISC-V: Add custom RTEMS multilibs

Add multilib variants for -march=rv64imafd, e.g. to support the BOOMv2 core.

Add -mcmodel=medany as a variant of the 64-bit multilibs for RTEMS.  The
rationale for this change is that several existing RISC-V chips map the
RAM at 0x80000000.  In RTEMS, we do not use virtual memory, so
applications will run at this location which is outside the +-2GiB range
in a 64-bit configuration.

gcc/
	* config.gcc (riscv*-*-elf* | riscv*-*-rtems*): Use custom
	multilibs for *-*-rtems*.
	* config/riscv/t-rtems: New file.

From-SVN: r261619

gcc/ChangeLog

+2018-06-15  Sebastian Huber  <sebastian.huber@embedded-brains.de>
+
+	* config.gcc (riscv*-*-elf* | riscv*-*-rtems*): Use custom
+	multilibs for *-*-rtems*.
+	* config/riscv/t-rtems: New file.
+
 2018-06-14  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/86122

gcc/config.gcc

@@ -2080,10 +2080,17 @@ riscv*-*-linux*)
 	;;
 riscv*-*-elf* | riscv*-*-rtems*)
 	tm_file="elfos.h newlib-stdint.h ${tm_file} riscv/elf.h"
-	case "x${enable_multilib}" in
-	xno) ;;
-	xyes) tmake_file="${tmake_file} riscv/t-elf-multilib" ;;
-	*) echo "Unknown value for enable_multilib"; exit 1
+	case ${target} in
+	*-*-rtems*)
+	  tm_file="${tm_file} rtems.h riscv/rtems.h"
+	  tmake_file="${tmake_file} riscv/t-rtems"
+	  ;;
+	*)
+	  case "x${enable_multilib}" in
+	  xno) ;;
+	  xyes) tmake_file="${tmake_file} riscv/t-elf-multilib" ;;
+	  *) echo "Unknown value for enable_multilib"; exit 1
+	  esac
 	esac
 	tmake_file="${tmake_file} riscv/t-riscv"
 	gnu_ld=yes
@@ -2091,11 +2098,6 @@ riscv*-*-elf* | riscv*-*-rtems*)
 	# Force .init_array support.  The configure script cannot always
 	# automatically detect that GAS supports it, yet we require it.
 	gcc_cv_initfini_array=yes
-	case ${target} in
-	riscv*-*-rtems*)
-	  tm_file="${tm_file} rtems.h riscv/rtems.h"
-	  ;;
-	esac
 	;;
 riscv*-*-freebsd*)
 	tm_file="${tm_file} elfos.h ${fbsd_tm_file} riscv/freebsd.h"

gcc/config/riscv/t-rtems

+MULTILIB_OPTIONS	=
+MULTILIB_DIRNAMES	=
+
+MULTILIB_OPTIONS	+= march=rv32i/march=rv32im/march=rv32imafd/march=rv32iac/march=rv32imac/march=rv32imafc/march=rv64imafd/march=rv64imac/march=rv64imafdc
+MULTILIB_DIRNAMES	+= rv32i       rv32im       rv32imafd       rv32iac       rv32imac       rv32imafc       rv64imafd       rv64imac       rv64imafdc
+
+MULTILIB_OPTIONS	+= mabi=ilp32/mabi=ilp32f/mabi=ilp32d/mabi=lp64/mabi=lp64d
+MULTILIB_DIRNAMES	+= ilp32      ilp32f      ilp32d      lp64      lp64d
+
+MULTILIB_OPTIONS	+= mcmodel=medany
+MULTILIB_DIRNAMES	+= medany
+
+MULTILIB_REQUIRED	=
+MULTILIB_REQUIRED	+= march=rv32i/mabi=ilp32
+MULTILIB_REQUIRED	+= march=rv32im/mabi=ilp32
+MULTILIB_REQUIRED	+= march=rv32imafd/mabi=ilp32d
+MULTILIB_REQUIRED	+= march=rv32iac/mabi=ilp32
+MULTILIB_REQUIRED	+= march=rv32imac/mabi=ilp32
+MULTILIB_REQUIRED	+= march=rv32imafc/mabi=ilp32f
+MULTILIB_REQUIRED	+= march=rv64imafd/mabi=lp64d
+MULTILIB_REQUIRED	+= march=rv64imafd/mabi=lp64d/mcmodel=medany
+MULTILIB_REQUIRED	+= march=rv64imac/mabi=lp64
+MULTILIB_REQUIRED	+= march=rv64imac/mabi=lp64/mcmodel=medany
+MULTILIB_REQUIRED	+= march=rv64imafdc/mabi=lp64d
+MULTILIB_REQUIRED	+= march=rv64imafdc/mabi=lp64d/mcmodel=medany