GDB: set correct data model for x86_64-nacl

gdb/nacl-tdep.c

Index: gdb/nacl-tdep.c
diff --git a/gdb/nacl-tdep.c b/gdb/nacl-tdep.c
index 91db26266505d7c8edc26f3f3df889bb9363a586..edb376398bc6410b8ee3b97b0125e12c7df3dab4 100644
--- a/gdb/nacl-tdep.c
+++ b/gdb/nacl-tdep.c
@@ -81,6 +81,24 @@ amd64_nacl_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
   set_solib_svr4_fetch_link_map_offsets (gdbarch,
 					 svr4_lp64_fetch_link_map_offsets);
   nacl_init_abi (info, gdbarch);
+
+  /* NaCl data model.
+
+     WARNING! This might confuse a lot of code, as it uses
+       if (set_gdbarch_ptr_bit (gdbarch) == <bits>)
+     to distinguish between i386 and x86_64 (lame!).  Luckily, most of that
+     code is about native debugging and syscalls, so it is not used for NaCl.
+
+     TODO(eaeltsin): find better way to distinguish between i386 and x86_64!  */
+  set_gdbarch_long_bit (gdbarch, 32);
+  set_gdbarch_ptr_bit (gdbarch, 32);
+
+  /* TODO(eaeltsin): we might use address size instead of pointer size to
+     distinguish between i386 and x86_64...  At least address size is not
+     a property of the data model.  */
+  set_gdbarch_addr_bit (gdbarch, 64);
+
+  /* How to extract addresses from registers.  */
   set_gdbarch_addr_bits_remove (gdbarch, amd64_nacl_addr_bits_remove);
   set_gdbarch_unwind_pc (gdbarch, amd64_nacl_unwind_pc);
   set_gdbarch_unwind_sp (gdbarch, amd64_nacl_unwind_sp);