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

src/trusted/service_runtime/sel_main_chrome.c

Index: src/trusted/service_runtime/sel_main_chrome.c
diff --git a/src/trusted/service_runtime/sel_main_chrome.c b/src/trusted/service_runtime/sel_main_chrome.c
index 35dfa02a120fd8a4400c750dbf7c775d798a5766..781aaa0f6ae397fdb7b454446edb3763026f1395 100644
--- a/src/trusted/service_runtime/sel_main_chrome.c
+++ b/src/trusted/service_runtime/sel_main_chrome.c
@@ -30,6 +30,7 @@
 #include "native_client/src/trusted/service_runtime/nacl_all_modules.h"
 #include "native_client/src/trusted/service_runtime/nacl_debug_init.h"
 #include "native_client/src/trusted/service_runtime/nacl_signal.h"
+#include "native_client/src/trusted/service_runtime/nacl_text.h"
 #include "native_client/src/trusted/service_runtime/osx/mach_exception_handler.h"
 #include "native_client/src/trusted/service_runtime/sel_addrspace.h"
 #include "native_client/src/trusted/service_runtime/sel_ldr.h"
@@ -281,7 +282,19 @@ void NaClChromeMainStart(struct NaClChromeMainArgs *args) {
   }
 
   /* Load the integrated runtime (IRT) library. */
-  NaClLoadIrt(nap, args->irt_fd);
+  /* We check if there is a segment gap before trying to load the IRT.  This

[Mark Seaborn, 2012/06/28 22:05:11]

The comment style is
/*
 * blah
 * blah
 */

Can you combine this with the comment on the previous line?

[jvoung (off chromium), 2012/06/28 22:41:56]

Done.

+   * is to support IRT-less / segment-gap-free PNaCl translator nexes.
+   * We should plumb through a flag from Chrome in such cases, instead of

[Mark Seaborn, 2012/06/28 22:05:11]

Can you make this: "TODO(mseaborn): Plumb through a flag from Chromium for such
cases..." as a reminder to me.

[jvoung (off chromium), 2012/06/28 22:41:56]

Done.

+   * looking for the absence of a segment gap, to provide better diagnostics
+   * when the linker did not create a segment gap!
+   */
+  if (NaClHasSegmentGapForDyncode(nap)) {
+    NaClLoadIrt(nap, args->irt_fd);
+  } else {
+    NaClLog(LOG_WARNING,
+            "NaCl app doesn't have a segment gap, not loading IRT.\n"

[Mark Seaborn, 2012/06/28 22:05:11]

'executable' rather than 'app'?  "Main executable has no segment gap; skipping
loading IRT library..."

[jvoung (off chromium), 2012/06/28 22:41:56]

Done.

+            "This is expected for PNaCl's translator nexes.\n");
+  }
 
   NaClEnvCleanserCtor(&env_cleanser, 1);
   if (!NaClEnvCleanserInit(&env_cleanser, envp, NULL)) {