Allow sel_ldr to continue without the IRT, when nexe doesn't have segment gap

src/trusted/service_runtime/sel_main.c

Index: src/trusted/service_runtime/sel_main.c
diff --git a/src/trusted/service_runtime/sel_main.c b/src/trusted/service_runtime/sel_main.c
index 35a9b14dfb497aa509b42eb1253de2f0cbe995d5..58ba5ca34cd946da16b6e187686ff424264382c1 100644
--- a/src/trusted/service_runtime/sel_main.c
+++ b/src/trusted/service_runtime/sel_main.c
@@ -678,18 +678,28 @@ int main(int  argc,
     NaClGdbHook(&state);
   }
 
-
   if (NULL != blob_library_file) {
     if (LOAD_OK == errcode) {
-      NaClLog(2, "Loading blob file %s\n", blob_library_file);
-      errcode = NaClAppLoadFileDynamically(nap, (struct Gio *) &blob_file);
-      if (LOAD_OK != errcode) {
-        fprintf(stderr, "Error while loading \"%s\": %s\n",
-                blob_library_file,
-                NaClErrorString(errcode));
+      if (NULL != nap->text_shm) {
+        NaClLog(2, "Loading blob file %s\n", blob_library_file);
+        errcode = NaClAppLoadFileDynamically(nap, (struct Gio *) &blob_file);
+        if (LOAD_OK != errcode) {
+          fprintf(stderr, "Error while loading \"%s\": %s\n",
+                  blob_library_file,
+                  NaClErrorString(errcode));
+        }
+        NaClPerfCounterMark(&time_all_main, "BlobLoaded");
+        NaClPerfCounterIntervalLast(&time_all_main);
+      } else {
+        /*
+         * TODO(mseaborn): Omit -B when the IRT is not wanted (e.g., from
+         * sel_ldr_launcher_standalone), instead of looking for the absence
+         * of a segment gap, when the nexe does not follow NaCl's stable ABI.
+         */
+        NaClLog(LOG_WARNING,
+                "Main executable has no segment gap; not loading IRT library. "
+                "This is expected for PNaCl's translator nexes.\n");
       }
-      NaClPerfCounterMark(&time_all_main, "BlobLoaded");
-      NaClPerfCounterIntervalLast(&time_all_main);
     }
 
     if (-1 == (*((struct Gio *) &blob_file)->vtbl->Close)((struct Gio *)