Go patch committed: Fix varargs function that call recover

[Ian Lance Taylor]

The Go frontend mishandled varargs functions that call recover.  This
patch fixes that.  The patch also fixes a couple of other cases where
the compiler crashed on invalid input.  Bootstrapped and ran Go
testsuite on x86_64-unknown-linux-gnu.  Committed to mainline.

Ian


diff -r 0927d16a6df2 go/expressions.h
--- a/go/expressions.h	Wed Feb 29 21:59:00 2012 -0800
+++ b/go/expressions.h	Thu Mar 01 09:10:10 2012 -0800
@@ -1066,6 +1066,10 @@
   { return this->expr_; }
 
  protected:
+  int
+  do_traverse(Traverse* traverse)
+  { return Expression::traverse(&this->expr_, traverse); }
+
   Type*
   do_type();
 
diff -r 0927d16a6df2 go/gogo.cc
--- a/go/gogo.cc	Wed Feb 29 21:59:00 2012 -0800
+++ b/go/gogo.cc	Thu Mar 01 09:10:10 2012 -0800
@@ -2500,6 +2500,9 @@
 
   Call_expression* call = Expression::make_call(fn, args, false, location);
 
+  // Any varargs call has already been lowered.
+  call->set_varargs_are_lowered();
+
   Statement* s;
   if (orig_fntype->results() == NULL || orig_fntype->results()->empty())
     s = Statement::make_statement(call, true);
@@ -5346,5 +5349,5 @@
   else if (this->var_ != NULL)
     this->var_->add_preinit_statement(this->gogo_, s);
   else
-    go_unreachable();
-}
+    go_assert(saw_errors());
+}