Avoid deep, high-fanout productions in bool_expr::factory.

anse1 · anse1 · commit db32e9644f73 · 2018-05-03T19:39:36.000+02:00
This appears to provoke stack overflows when testing MonetDB.
diff --git a/expr.cc b/expr.cc
@@ -96,6 +96,8 @@ column_reference::column_reference(prod *p, sqltype *type_constraint) : value_ex
 shared_ptr<bool_expr> bool_expr::factory(prod *p)
 {
   try {
+       if (p->level > d100())
+	    return make_shared<truth_value>(p);
        if(d6() < 4)
 	    return make_shared<comparison_op>(p);
        else if (d6() < 4)

Original file line number	Diff line number	Diff line change
`@@ -96,6 +96,8 @@ column_reference::column_reference(prod p, sqltype type_constraint) : value_ex`
`96`	`96`	`shared_ptr<bool_expr> bool_expr::factory(prod *p)`
`97`	`97`	`{`
`98`	`98`	`try {`
	`99`	`+ if (p->level > d100())`
	`100`	`+ return make_shared<truth_value>(p);`
`99`	`101`	`if(d6() < 4)`
`100`	`102`	`return make_shared<comparison_op>(p);`
`101`	`103`	`else if (d6() < 4)`