PPC gold doesn't check for overflow properly

[Cary Coutant]

In rela(), you pass (value >> right_shift) to overflowed():

     return overflowed<valsize>(value >> right_shift, overflow);

But in addr24(), you pass a valsize of 26:

+    Status stat = This::template rela<32,26>(view, 0, 0x03fffffc,
+                                            value, overflow);

Given the right shift, shouldn't that be 24?

(addr14() uses a right shift of 0, so valsize == 16 looks right for that case.)

-  if (status != Powerpc_relocate_functions<size, big_endian>::STATUS_OK)
-    gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
-                          _("relocation overflow"));
+  if (status != Powerpc_relocate_functions<size, big_endian>::STATUS_OK
+      && !has_stub_value
+      && !(gsym != NULL
+          && gsym->is_weak_undefined()
+          && is_branch_reloc(r_type)))
+    {
+      gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
+                            _("relocation overflow"));
+      if (has_stub_value)
+       gold_info(_("try relinking with a smaller --stub-group-size"));
+    }

With !has_stub_value in the outer condition, I don't think that info
message will ever get printed. Why add all the new conditions? Should
those be guarding only the new info message?

-cary