This patch to the Go frontend by Cherry Zhang stack allocates defer
thunk when possible, which is to say when the defer statement is not
in a loop. Bootstrapped on x86_64-pc-linux-gnu. Committed to
mainline.
Ian
Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE (revision 256407)
+++ gcc/go/gofrontend/MERGE (working copy)
@@ -1,4 +1,4 @@
-d5774539b17112d9ce709a1fe722daf68eb8594f
+7c5e4d67041e3529a055a923b2b9f5ef09aa72a3
The first line of this file holds the git revision number of the last
merge done from the gofrontend repository.
Index: gcc/go/gofrontend/escape.cc
===================================================================
--- gcc/go/gofrontend/escape.cc (revision 256405)
+++ gcc/go/gofrontend/escape.cc (working copy)
@@ -1420,7 +1420,14 @@ Escape_analysis_assign::statement(Block*
case Statement::STATEMENT_DEFER:
if (this->context_->loop_depth() == 1)
- break;
+ {
+ // Defer statement may need to allocate a thunk. When it is
+ // not inside a loop, this can be stack allocated, as it
+ // runs before the function finishes.
+ Node* n = Node::make_node(s);
+ n->set_encoding(Node::ESCAPE_NONE);
+ break;
+ }
// fallthrough
case Statement::STATEMENT_GO:
Index: gcc/go/gofrontend/statements.cc
===================================================================
--- gcc/go/gofrontend/statements.cc (revision 256366)
+++ gcc/go/gofrontend/statements.cc (working copy)
@@ -2156,6 +2156,8 @@ Thunk_statement::simplify_statement(Gogo
// Allocate the initialized struct on the heap.
constructor = Expression::make_heap_expression(constructor, location);
+ if ((Node::make_node(this)->encoding() & ESCAPE_MASK) == Node::ESCAPE_NONE)
+ constructor->heap_expression()->set_allocate_on_stack();
// Throw an error if the function is nil. This is so that for `go
// nil` we get a backtrace from the go statement, rather than a
