RISC-V: Build infrastructure for 32-bit port

This patch lays out the top-level organisation of the RISC-V 32-bit port.
It provides all the Implies files as well as various other fragments of
the build infrastructure.

Reviewed-by: Maciej W. Rozycki <macro@wdc.com>

sysdeps/riscv/preconfigure

@@ -6,11 +6,7 @@ riscv*)
     atomic=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null | grep '#define __riscv_atomic' | cut -d' ' -f2`
 
     case "$xlen" in
-    32)
+    64 | 32)
-	echo "glibc does not yet support 32-bit systems" >&2
-	exit 1
-	;;
-    64)
 	;;
     *)
 	echo "Unable to determine XLEN" >&2

sysdeps/riscv/rv32/Implies-after

@@ -0,0 +1 @@
+wordsize-32

sysdeps/riscv/rv32/rvd/Implies

@@ -0,0 +1,3 @@
+riscv/rv32/rvf
+riscv/rvd
+riscv/rvf

sysdeps/riscv/rv32/rvf/Implies

@@ -0,0 +1 @@
+riscv/rvf

sysdeps/unix/sysv/linux/riscv/Makefile

@@ -7,11 +7,13 @@ ifeq ($(subdir),stdlib)
 gen-as-const-headers += ucontext_i.sym
 endif
 
-abi-variants := lp64 lp64d
+abi-variants := ilp32 ilp32d lp64 lp64d
 
 ifeq (,$(filter $(default-abi),$(abi-variants)))
 $(error Unknown ABI $(default-abi), must be one of $(abi-variants))
 endif
 
-abi-lp64-condition    := defined __LP64__ && defined __riscv_float_abi_soft
+abi-ilp32-condition   := __WORDSIZE == 32 && defined __riscv_float_abi_soft
-abi-lp64d-condition   := defined __LP64__ && defined __riscv_float_abi_double
+abi-ilp32d-condition  := __WORDSIZE == 32 && defined __riscv_float_abi_double
+abi-lp64-condition    := __WORDSIZE == 64 && defined __riscv_float_abi_soft
+abi-lp64d-condition   := __WORDSIZE == 64 && defined __riscv_float_abi_double

sysdeps/unix/sysv/linux/riscv/configure

@@ -147,6 +147,17 @@ if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
 fi
 rm -f conftest*
 
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+__SIZEOF_INT__ __SIZEOF_LONG__ __SIZEOF_POINTER__
+
+_ACEOF
+if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+  $EGREP "4 4 4" >/dev/null 2>&1; then :
+  libc_cv_riscv_int_abi=ilp32
+fi
+rm -f conftest*
+
 if test $libc_cv_riscv_int_abi = no; then
   as_fn_error $? "Unable to determine integer ABI" "$LINENO" 5
 fi
@@ -218,6 +229,34 @@ case "$prefix" in
   ;;
 esac
   ;;
+ilp32-riscv/rv32/*)
+  test -n "$libc_cv_slibdir" ||
+case "$prefix" in
+/usr | /usr/)
+  libc_cv_slibdir='/lib32/ilp32'
+  libc_cv_rtlddir='/lib'
+  if test "$libdir" = '${exec_prefix}/lib'; then
+    libdir='${exec_prefix}/lib32/ilp32';
+    # Locale data can be shared between 32-bit and 64-bit libraries.
+    libc_cv_complocaledir='${exec_prefix}/lib/locale'
+  fi
+  ;;
+esac
+  ;;
+ilp32d-riscv/rv32/*)
+  test -n "$libc_cv_slibdir" ||
+case "$prefix" in
+/usr | /usr/)
+  libc_cv_slibdir='/lib32/ilp32d'
+  libc_cv_rtlddir='/lib'
+  if test "$libdir" = '${exec_prefix}/lib'; then
+    libdir='${exec_prefix}/lib32/ilp32d';
+    # Locale data can be shared between 32-bit and 64-bit libraries.
+    libc_cv_complocaledir='${exec_prefix}/lib/locale'
+  fi
+  ;;
+esac
+  ;;
 esac
 
 ldd_rewrite_script=sysdeps/unix/sysv/linux/riscv/ldd-rewrite.sed

sysdeps/unix/sysv/linux/riscv/configure.ac

@@ -7,6 +7,8 @@ arch_minimum_kernel=4.15.0
 libc_cv_riscv_int_abi=no
 AC_EGREP_CPP(4 8 8, [__SIZEOF_INT__ __SIZEOF_LONG__ __SIZEOF_POINTER__
   ], libc_cv_riscv_int_abi=lp64)
+AC_EGREP_CPP(4 4 4, [__SIZEOF_INT__ __SIZEOF_LONG__ __SIZEOF_POINTER__
+  ], libc_cv_riscv_int_abi=ilp32)
 if test $libc_cv_riscv_int_abi = no; then
   AC_MSG_ERROR([Unable to determine integer ABI])
 fi
@@ -37,6 +39,12 @@ lp64-riscv/rv64/*)
 lp64d-riscv/rv64/*)
   LIBC_SLIBDIR_RTLDDIR([lib64/lp64d], [lib])
   ;;
+ilp32-riscv/rv32/*)
+  LIBC_SLIBDIR_RTLDDIR([lib32/ilp32], [lib])
+  ;;
+ilp32d-riscv/rv32/*)
+  LIBC_SLIBDIR_RTLDDIR([lib32/ilp32d], [lib])
+  ;;
 esac
 
 ldd_rewrite_script=sysdeps/unix/sysv/linux/riscv/ldd-rewrite.sed

sysdeps/unix/sysv/linux/riscv/rv32/Implies

@@ -0,0 +1,3 @@
+unix/sysv/linux/riscv
+unix/sysv/linux/generic/wordsize-32
+unix/sysv/linux/generic

sysdeps/unix/sysv/linux/riscv/shlib-versions

@@ -1,9 +1,15 @@
-DEFAULT		GLIBC_2.27
-
 %if RISCV_ABI_XLEN == 64 && RISCV_ABI_FLEN == 64
+DEFAULT		GLIBC_2.27
 ld=ld-linux-riscv64-lp64d.so.1
 %elif RISCV_ABI_XLEN == 64 && RISCV_ABI_FLEN == 0
+DEFAULT		GLIBC_2.27
 ld=ld-linux-riscv64-lp64.so.1
+%elif RISCV_ABI_XLEN == 32 && RISCV_ABI_FLEN == 64
+DEFAULT		GLIBC_2.33
+ld=ld-linux-riscv32-ilp32d.so.1
+%elif RISCV_ABI_XLEN == 32 && RISCV_ABI_FLEN == 0
+DEFAULT		GLIBC_2.33
+ld=ld-linux-riscv32-ilp32.so.1
 %else
 %error cannot determine ABI
 %endif