Don't modify memory access right when changing data in debug stub.

tests/gdb/gdb_test_guest.c

Index: tests/gdb/gdb_test_guest.c
===================================================================
--- tests/gdb/gdb_test_guest.c	(revision 9612)
+++ tests/gdb/gdb_test_guest.c	(working copy)
@@ -54,6 +54,11 @@
   global_ptr = alloca(arg);
 }
 
+int test_call_from_gdb(int arg) {
+  global_var = 2 * arg;
+  return 3 * arg;
+}
+
 int main(int argc, char **argv) {
   assert(argc >= 2);
 
@@ -77,5 +82,9 @@
     test_step_from_function_start(2);
     return 0;
   }
+  if (strcmp(argv[1], "call_from_gdb") == 0) {
+    /* Call function so that it doesn't optimized away. */

[Mark Seaborn, 2012/08/31 16:40:13]

"doesn't get optimized".  However, this shouldn't be necessary:  it shouldn't
get optimised away because:
 1) we don't use link-time optimisation with gcc, and the object file for this
file must include test_call_from_gdb();
 2) we build with -O0.

But also this wouldn't be sufficient in the case of LTO (e.g. with PNaCl),
because the function could get inlined away.

I'm just saying.  You don't necessarily need to change this.

[halyavin, 2012/09/03 10:33:50]

Done.

+    return test_call_from_gdb(0);
+  }
   return 1;
 }