Option to output precompiled instructions as a blob for use with mmap instead of assembly for use i…

runtime/bin/file_macos.cc

Index: runtime/bin/file_macos.cc
diff --git a/runtime/bin/file_macos.cc b/runtime/bin/file_macos.cc
index 03c27c3ba114d108487a0939cee8dc2aece45b86..941d419352b64e904631ada3b4041d1942d37e05 100644
--- a/runtime/bin/file_macos.cc
+++ b/runtime/bin/file_macos.cc
@@ -12,6 +12,7 @@
 #include <fcntl.h>  // NOLINT
 #include <libgen.h>  // NOLINT
 #include <limits.h>  // NOLINT
+#include <sys/mman.h>  // NOLINT
 #include <sys/stat.h>  // NOLINT
 #include <unistd.h>  // NOLINT
 
@@ -78,6 +79,21 @@ bool File::IsClosed() {
 }
 
 
+void* File::MapExecutable(intptr_t* len) {
+  ASSERT(handle_->fd() >= 0);
+  intptr_t length = Length();
+  void* addr = mmap(0, length,
+                    PROT_READ | PROT_EXEC, MAP_PRIVATE,
+                    handle_->fd(), 0);
+  if (addr == MAP_FAILED) {
+    *len = -1;
+  } else {
+    *len = length;
+  }
+  return addr;
+}
+
+
 int64_t File::Read(void* buffer, int64_t num_bytes) {
   ASSERT(handle_->fd() >= 0);
   return TEMP_FAILURE_RETRY(read(handle_->fd(), buffer, num_bytes));