This patch to the Go frontend changes it to not produce a closure for an
embedded function if one is not needed. Earlier, when Go permitted
comparisons of function types, it was necessary to always create a
closure for an embedded function, so that each embedded function would
be reliably distinct. Go 1 removed function comparisons, for this and
other reasons. Now, if an embedded function does not require a closure,
because it does not refer to any variables defined in enclosing
functions, we don't need to create a closure. Bootstrapped and ran Go
testsuite on x86_64-unknown-linux-gnu. Committed to mainline and 4.7
branch.
Ian
diff -r b7d2ae6bea1b go/expressions.cc
--- a/go/expressions.cc Fri May 25 11:21:08 2012 -0700
+++ b/go/expressions.cc Fri May 25 14:11:54 2012 -0700
@@ -1312,30 +1312,18 @@
&& TREE_CODE(TREE_OPERAND(fnaddr, 0)) == FUNCTION_DECL);
TREE_ADDRESSABLE(TREE_OPERAND(fnaddr, 0)) = 1;
- // For a normal non-nested function call, that is all we have to do.
- if (!this->function_->is_function()
- || this->function_->func_value()->enclosing() == NULL)
- {
- go_assert(this->closure_ == NULL);
- return fnaddr;
- }
-
- // For a nested function call, we have to always allocate a
- // trampoline. If we don't always allocate, then closures will not
- // be reliably distinct.
- Expression* closure = this->closure_;
- tree closure_tree;
- if (closure == NULL)
- closure_tree = null_pointer_node;
- else
- {
- // Get the value of the closure. This will be a pointer to
- // space allocated on the heap.
- closure_tree = closure->get_tree(context);
- if (closure_tree == error_mark_node)
- return error_mark_node;
- go_assert(POINTER_TYPE_P(TREE_TYPE(closure_tree)));
- }
+ // If there is no closure, that is all have to do.
+ if (this->closure_ == NULL)
+ return fnaddr;
+
+ go_assert(this->function_->func_value()->enclosing() != NULL);
+
+ // Get the value of the closure. This will be a pointer to space
+ // allocated on the heap.
+ tree closure_tree = this->closure_->get_tree(context);
+ if (closure_tree == error_mark_node)
+ return error_mark_node;
+ go_assert(POINTER_TYPE_P(TREE_TYPE(closure_tree)));
// Now we need to build some code on the heap. This code will load
// the static chain pointer with the closure and then jump to the
