Subzero: Add a script that builds a hybrid Subzero/llc native executable.

runtime/szrt.c

+//===- subzero/runtime/szrt.c - Subzero runtime source ----------*- C++ -*-===//
+//
+//                        The Subzero Code Generator
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the runtime helper routines that are needed by
+// Subzero.  This needs to be compiled by some non-Subzero compiler.
+//
+//===----------------------------------------------------------------------===//
+
+#include <stdint.h>
+#include <stdlib.h>
+
+void ice_unreachable(void) {
+  abort();
+}
+
+uint32_t cvtftoui32(float value) {
+  return (uint32_t) value;
+}
+
+uint32_t cvtdtoui32(double value) {
+  return (uint32_t) value;
+}
+
+int64_t cvtftosi64(float value) {
+  return (int64_t) value;
+}
+
+int64_t cvtdtosi64(double value) {
+  return (int64_t) value;
+}
+
+uint64_t cvtftoui64(float value) {
+  return (uint64_t) value;
+}
+
+uint64_t cvtdtoui64(double value) {
+  return (uint64_t) value;
+}
+
+float cvtui32tof(uint32_t value) {
+  return (float) value;
+}
+
+float cvtsi64tof(int64_t value) {
+  return (float) value;
+}
+
+float cvtui64tof(uint64_t value) {
+  return (float) value;
+}
+
+double cvtui32tod(uint32_t value) {
+  return (double) value;
+}
+
+double cvtsi64tod(int64_t value) {
+  return (double) value;
+}
+
+double cvtui64tod(uint64_t value) {
+  return (double) value;
+}
+
+/* TODO(stichnot):
+   Sz_fptoui_v4f32
+   Sz_uitofp_v4i32
+   Sz_bitcast_v8i1_to_i8
+   Sz_bitcast_v16i1_to_i16
+   Sz_bitcast_i8_to_v8i1
+   Sz_bitcast_i16_to_v16i1
+*/