8226287: Make process_users_of_allocation handle gc barriers
Reviewed-by: kvn, roland
--- a/src/hotspot/share/gc/shared/c2/barrierSetC2.hpp Mon Jul 01 12:50:34 2019 +0800
+++ b/src/hotspot/share/gc/shared/c2/barrierSetC2.hpp Mon Jul 01 10:49:58 2019 +0200
@@ -267,6 +267,7 @@
virtual bool has_load_barriers() const { return false; }
virtual bool is_gc_barrier_node(Node* node) const { return false; }
virtual Node* step_over_gc_barrier(Node* c) const { return c; }
+ virtual Node* step_over_gc_barrier_ctrl(Node* c) const { return c; }
// Support for macro expanded GC barriers
virtual void register_potential_barrier_node(Node* node) const { }
--- a/src/hotspot/share/gc/z/c2/zBarrierSetC2.cpp Mon Jul 01 12:50:34 2019 +0800
+++ b/src/hotspot/share/gc/z/c2/zBarrierSetC2.cpp Mon Jul 01 10:49:58 2019 +0200
@@ -522,7 +522,7 @@
Node* in_val = barrier->in(LoadBarrierNode::Oop);
Node* in_adr = barrier->in(LoadBarrierNode::Address);
- Node* out_ctrl = barrier->proj_out_or_null(LoadBarrierNode::Control);
+ Node* out_ctrl = barrier->proj_out(LoadBarrierNode::Control);
Node* out_res = barrier->proj_out(LoadBarrierNode::Oop);
assert(barrier->in(LoadBarrierNode::Oop) != NULL, "oop to loadbarrier node cannot be null");
@@ -552,9 +552,8 @@
result_phi->set_req(1, new_loadp);
result_phi->set_req(2, barrier->in(LoadBarrierNode::Oop));
- if (out_ctrl != NULL) {
- igvn.replace_node(out_ctrl, result_region);
- }
+
+ igvn.replace_node(out_ctrl, result_region);
igvn.replace_node(out_res, result_phi);
assert(barrier->outcnt() == 0,"LoadBarrier macro node has non-null outputs after expansion!");
@@ -640,6 +639,22 @@
return c;
}
+Node* ZBarrierSetC2::step_over_gc_barrier_ctrl(Node* c) const {
+ Node* node = c;
+
+ // 1. This step follows potential ctrl projections of a load barrier before expansion
+ if (node->is_Proj()) {
+ node = node->in(0);
+ }
+
+ // 2. This step checks for unexpanded load barriers
+ if (node->is_LoadBarrier()) {
+ return node->in(LoadBarrierNode::Control);
+ }
+
+ return c;
+}
+
bool ZBarrierSetC2::array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, ArrayCopyPhase phase) const {
return type == T_OBJECT || type == T_ARRAY;
}
--- a/src/hotspot/share/gc/z/c2/zBarrierSetC2.hpp Mon Jul 01 12:50:34 2019 +0800
+++ b/src/hotspot/share/gc/z/c2/zBarrierSetC2.hpp Mon Jul 01 10:49:58 2019 +0200
@@ -182,6 +182,7 @@
virtual bool has_load_barriers() const { return true; }
virtual bool is_gc_barrier_node(Node* node) const;
virtual Node* step_over_gc_barrier(Node* c) const;
+ virtual Node* step_over_gc_barrier_ctrl(Node* c) const;
virtual void register_potential_barrier_node(Node* node) const;
virtual void unregister_potential_barrier_node(Node* node) const;
--- a/src/hotspot/share/opto/macro.cpp Mon Jul 01 12:50:34 2019 +0800
+++ b/src/hotspot/share/opto/macro.cpp Mon Jul 01 10:49:58 2019 +0200
@@ -1008,8 +1008,17 @@
assert(init->outcnt() <= 2, "only a control and memory projection expected");
Node *ctrl_proj = init->proj_out_or_null(TypeFunc::Control);
if (ctrl_proj != NULL) {
- assert(init->in(TypeFunc::Control) == _fallthroughcatchproj, "allocation control projection");
- _igvn.replace_node(ctrl_proj, _fallthroughcatchproj);
+ _igvn.replace_node(ctrl_proj, init->in(TypeFunc::Control));
+#ifdef ASSERT
+ BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
+ Node* tmp = init->in(TypeFunc::Control);
+ while (bs->is_gc_barrier_node(tmp)) {
+ Node* tmp2 = bs->step_over_gc_barrier_ctrl(tmp);
+ assert(tmp != tmp2, "Must make progress");
+ tmp = tmp2;
+ }
+ assert(tmp == _fallthroughcatchproj, "allocation control projection");
+#endif
}
Node *mem_proj = init->proj_out_or_null(TypeFunc::Memory);
if (mem_proj != NULL) {