Merge pull request #3618 from martin-frbg/issue3606

Automatically downgrade C910V to RISCV64_GENERIC if the compiler lacks vector support

Author: martin-frbg

Makefile.prebuild

@@ -72,7 +72,8 @@ endif
 
 getarch : getarch.c cpuid.S dummy $(CPUIDEMU)
 	avx512=$$(perl c_check - - $(CC) $(TARGET_FLAGS) $(CFLAGS) | grep NO_AVX512); \
-	$(HOSTCC) $(HOST_CFLAGS) $(EXFLAGS) $${avx512:+-D$${avx512}} -o $(@F) getarch.c cpuid.S $(CPUIDEMU)
+	rv64gv=$$(perl c_check - - $(CC) $(TARGET_FLAGS) $(CFLAGS) | grep NO_RV64GV); \
+	$(HOSTCC) $(HOST_CFLAGS) $(EXFLAGS) $${avx512:+-D$${avx512}} $${rv64gv:+-D$${rv64gv}} -o $(@F) getarch.c cpuid.S $(CPUIDEMU)
 
 getarch_2nd : getarch_2nd.c $(TARGET_CONF) dummy
 ifndef TARGET_CORE

c_check

@@ -270,6 +270,29 @@ if (($architecture eq "x86") || ($architecture eq "x86_64")) {
     }
 }
 
+$no_rv64gv= 0;
+if (($architecture eq "riscv64")) {
+    eval "use File::Temp qw(tempfile)";
+    if ($@){ 
+	warn "could not load PERL module File::Temp, so could not check compiler compatibility with the RISCV vector extension";
+	$no_rv64gv = 0;
+    } else {
+#	$tmpf = new File::Temp( UNLINK => 1 );
+	($fh,$tmpf) = tempfile( SUFFIX => '.c' , UNLINK => 1 );
+	$code = '"vsetvli    zero, zero, e8, m1\n"';
+	print $fh "int main(void){ __asm__ volatile($code); }\n";
+	$args = " -march=rv64gv -c -o $tmpf.o $tmpf";
+	my @cmd = ("$compiler_name $flags $args >/dev/null 2>/dev/null");
+	system(@cmd) == 0;
+	if ($? != 0) {
+	    $no_rv64gv = 1;
+	} else {
+	    $no_rv64gv = 0;
+	}
+	unlink("$tmpf.o");
+    }
+}
+
 $c11_atomics = 0;
 if ($data =~ /HAVE_C11/) {
     eval "use File::Temp qw(tempfile)";
@@ -392,6 +415,7 @@ print MAKEFILE "CROSS=1\n" if $cross != 0;
 print MAKEFILE "CEXTRALIB=$linker_L $linker_l $linker_a\n";
 print MAKEFILE "HAVE_MSA=1\n" if $have_msa eq 1;
 print MAKEFILE "MSA_FLAGS=$msa_flags\n" if $have_msa eq 1;
+print MAKEFILE "NO_RV64GV=1\n" if $no_rv64gv eq 1;
 print MAKEFILE "NO_AVX512=1\n" if $no_avx512 eq 1;
 print MAKEFILE "NO_AVX2=1\n" if $no_avx2 eq 1;
 print MAKEFILE "OLDGCC=1\n" if $oldgcc eq 1;

getarch.c

@@ -1574,6 +1574,16 @@ USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifdef FORCE_C910V
 #define FORCE
 #define ARCHITECTURE    "RISCV64"
+#ifdef NO_RV64GV
+#define SUBARCHITECTURE "RISCV64_GENERIC"
+#define SUBDIRNAME      "riscv64"
+#define ARCHCONFIG   "-DRISCV64_GENERIC " \
+       "-DL1_DATA_SIZE=32768 -DL1_DATA_LINESIZE=32 " \
+       "-DL2_SIZE=1048576 -DL2_LINESIZE=32 " \
+       "-DDTB_DEFAULT_ENTRIES=128 -DDTB_SIZE=4096 -DL2_ASSOCIATIVE=4 "
+#define LIBNAME   "riscv64_generic"
+#define CORENAME  "RISCV64_GENERIC"
+#else
 #define SUBARCHITECTURE "C910V"
 #define SUBDIRNAME      "riscv64"
 #define ARCHCONFIG   "-DC910V " \
@@ -1582,6 +1592,7 @@ USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
        "-DDTB_DEFAULT_ENTRIES=128 -DDTB_SIZE=4096 -DL2_ASSOCIATIVE=4 "
 #define LIBNAME   "c910v"
 #define CORENAME  "C910V"
+#endif
 #else
 #endif