RISC-V: Use an autoconf template to produce `preconfigure'

Avoid fiddling with autoconf internals and use AC_DEFINE_UNQUOTED to
define macros in the configuration headers rather than handcoding an
equivalent shell sequence with the use of the `as_echo' undocumented
variable.

Switch to using AC_MSG_ERROR rather than `echo' and `exit' directly for
error handling.  Owing to the lack of any kind of error annotation it
makes it difficult to spot the message in the flood in a parallel build
and neither it is logged in `config.log'.

Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>

2 files changed, 82 insertions, 15 deletions

diff --git a/sysdeps/riscv/preconfigure b/sysdeps/riscv/preconfigure
index 1ab5d20f0e..4dedf4b0bb 100644
--- a/sysdeps/riscv/preconfigure
+++ b/sysdeps/riscv/preconfigure
@@ -1,3 +1,6 @@
+# This file is generated from configure.ac by Autoconf.  DO NOT EDIT!
+# Local preconfigure fragment for sysdeps/riscv
+
 case "$machine" in
 riscv*)
     xlen=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null | sed -n 's/^#define __riscv_xlen \(.*\)/\1/p'`
@@ -9,8 +12,7 @@ riscv*)
     64 | 32)
 	;;
     *)
-	echo "Unable to determine XLEN" >&2
-	exit 1
+	as_fn_error 1 "Unable to determine XLEN" "$LINENO" 5
 	;;
     esac
 
@@ -20,15 +22,13 @@ riscv*)
 	with_fp_cond=1
 	;;
     32)
-	echo "glibc does not yet support systems with the F but not D extensions" >&2
-	exit 1
+	as_fn_error 1 "glibc does not yet support systems with the F but not D extensions" "$LINENO" 5
 	;;
     "")
 	with_fp_cond=0
 	;;
     *)
-	echo "Unable to determine FLEN" >&2
-	exit 1
+	as_fn_error 1 "Unable to determine FLEN" "$LINENO" 5
 	;;
     esac
 
@@ -37,31 +37,34 @@ riscv*)
 	abi_flen=0
 	;;
     single)
-	echo "glibc does not yet support the single floating-point ABI" >&2
-	exit 1
+	as_fn_error 1 "glibc does not yet support the single floating-point ABI" "$LINENO" 5
 	;;
     double)
 	abi_flen=64
 	;;
     *)
-	echo "Unable to determine floating-point ABI" >&2
-	exit 1
+	as_fn_error 1 "Unable to determine floating-point ABI" "$LINENO" 5
 	;;
     esac
 
     case "$atomic" in
     __riscv_atomic)
-        ;;
+	;;
     *)
-        echo "glibc requires the A extension" >&2
-	exit 1
+	as_fn_error 1 "glibc requires the A extension" "$LINENO" 5
 	;;
     esac
 
     base_machine=riscv
     machine=riscv/rv$xlen/$float_machine
 
-    $as_echo "#define RISCV_ABI_XLEN $xlen" >>confdefs.h
-    $as_echo "#define RISCV_ABI_FLEN $abi_flen" >>confdefs.h
+    cat >>confdefs.h <<_ACEOF
+#define RISCV_ABI_XLEN $xlen
+_ACEOF
+
+    cat >>confdefs.h <<_ACEOF
+#define RISCV_ABI_FLEN $abi_flen
+_ACEOF
+
     ;;
 esac
diff --git a/sysdeps/riscv/preconfigure.ac b/sysdeps/riscv/preconfigure.ac
new file mode 100644
index 0000000000..a5c30e0dbf
--- /dev/null
+++ b/sysdeps/riscv/preconfigure.ac
@@ -0,0 +1,64 @@
+GLIBC_PROVIDES[]dnl See aclocal.m4 in the top level source directory.
+# Local preconfigure fragment for sysdeps/riscv
+
+case "$machine" in
+riscv*)
+    xlen=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null | sed -n 's/^#define __riscv_xlen \(.*\)/\1/p'`
+    flen=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null | sed -n 's/^#define __riscv_flen \(.*\)/\1/p'`
+    float_abi=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null | sed -n 's/^#define __riscv_float_abi_\([^ ]*\) .*/\1/p'`
+    atomic=`$CC $CFLAGS $CPPFLAGS -E -dM -xc /dev/null | grep '#define __riscv_atomic' | cut -d' ' -f2`
+
+    case "$xlen" in
+    64 | 32)
+	;;
+    *)
+	AC_MSG_ERROR([Unable to determine XLEN], [1])
+	;;
+    esac
+
+    case "$flen" in
+    64)
+	float_machine=rvd
+	with_fp_cond=1
+	;;
+    32)
+	AC_MSG_ERROR([glibc does not yet support systems with the F but not D extensions], 1)
+	;;
+    "")
+	with_fp_cond=0
+	;;
+    *)
+	AC_MSG_ERROR([Unable to determine FLEN], [1])
+	;;
+    esac
+
+    case "$float_abi" in
+    soft)
+	abi_flen=0
+	;;
+    single)
+	AC_MSG_ERROR([glibc does not yet support the single floating-point ABI], [1])
+	;;
+    double)
+	abi_flen=64
+	;;
+    *)
+	AC_MSG_ERROR([Unable to determine floating-point ABI], [1])
+	;;
+    esac
+
+    case "$atomic" in
+    __riscv_atomic)
+	;;
+    *)
+	AC_MSG_ERROR([glibc requires the A extension], [1])
+	;;
+    esac
+
+    base_machine=riscv
+    machine=riscv/rv$xlen/$float_machine
+
+    AC_DEFINE_UNQUOTED([RISCV_ABI_XLEN], [$xlen])
+    AC_DEFINE_UNQUOTED([RISCV_ABI_FLEN], [$abi_flen])
+    ;;
+esac