8285835: SIGSEGV in PhaseIdealLoop::build_loop_late_post_work

Backport-of: 8aa1526b443025b8606a3668262f46a9cb6ea6f6

Author: TobiHartmann

src/hotspot/share/opto/escape.cpp

@@ -281,7 +281,9 @@ bool ConnectionGraph::compute_escape() {
   // 3. Adjust scalar_replaceable state of nonescaping objects and push
   //    scalar replaceable allocations on alloc_worklist for processing
   //    in split_unique_types().
+  GrowableArray<JavaObjectNode*> jobj_worklist;
   int non_escaped_length = non_escaped_allocs_worklist.length();
+  bool found_nsr_alloc = false;
   for (int next = 0; next < non_escaped_length; next++) {
     JavaObjectNode* ptn = non_escaped_allocs_worklist.at(next);
     bool noescape = (ptn->escape_state() == PointsToNode::NoEscape);
@@ -292,11 +294,25 @@ bool ConnectionGraph::compute_escape() {
     if (noescape && ptn->scalar_replaceable()) {
       adjust_scalar_replaceable_state(ptn);
       if (ptn->scalar_replaceable()) {
-        alloc_worklist.append(ptn->ideal_node());
+        jobj_worklist.push(ptn);
+      } else {
+        found_nsr_alloc = true;
       }
     }
   }
 
+  // Propagate NSR (Not Scalar Replaceable) state.
+  if (found_nsr_alloc) {
+    find_scalar_replaceable_allocs(jobj_worklist);
+  }
+
+  for (int next = 0; next < jobj_worklist.length(); ++next) {
+    JavaObjectNode* jobj = jobj_worklist.at(next);
+    if (jobj->scalar_replaceable()) {
+      alloc_worklist.append(jobj->ideal_node());
+    }
+  }
+
 #ifdef ASSERT
   if (VerifyConnectionGraph) {
     // Verify that graph is complete - no new edges could be added or needed.
@@ -1865,15 +1881,19 @@ void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
         set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored at unknown offset"));
         return;
       }
-      // 2. An object is not scalar replaceable if the field into which it is
-      // stored has multiple bases one of which is null.
-      if (field->base_count() > 1) {
-        for (BaseIterator i(field); i.has_next(); i.next()) {
-          PointsToNode* base = i.get();
-          if (base == null_obj) {
-            set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with potentially null base"));
-            return;
-          }
+      for (BaseIterator i(field); i.has_next(); i.next()) {
+        PointsToNode* base = i.get();
+        // 2. An object is not scalar replaceable if the field into which it is
+        // stored has multiple bases one of which is null.
+        if ((base == null_obj) && (field->base_count() > 1)) {
+          set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with potentially null base"));
+          return;
+        }
+        // 2.5. An object is not scalar replaceable if the field into which it is
+        // stored has NSR base.
+        if (!base->scalar_replaceable()) {
+          set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with NSR base"));
+          return;
         }
       }
     }
@@ -1963,6 +1983,36 @@ void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
   }
 }
 
+// Propagate NSR (Not scalar replaceable) state.
+void ConnectionGraph::find_scalar_replaceable_allocs(GrowableArray<JavaObjectNode*>& jobj_worklist) {
+  int jobj_length = jobj_worklist.length();
+  bool found_nsr_alloc = true;
+  while (found_nsr_alloc) {
+    found_nsr_alloc = false;
+    for (int next = 0; next < jobj_length; ++next) {
+      JavaObjectNode* jobj = jobj_worklist.at(next);
+      for (UseIterator i(jobj); (jobj->scalar_replaceable() && i.has_next()); i.next()) {
+        PointsToNode* use = i.get();
+        if (use->is_Field()) {
+          FieldNode* field = use->as_Field();
+          assert(field->is_oop() && field->scalar_replaceable(), "sanity");
+          assert(field->offset() != Type::OffsetBot, "sanity");
+          for (BaseIterator i(field); i.has_next(); i.next()) {
+            PointsToNode* base = i.get();
+            // An object is not scalar replaceable if the field into which
+            // it is stored has NSR base.
+            if ((base != null_obj) && !base->scalar_replaceable()) {
+              set_not_scalar_replaceable(jobj NOT_PRODUCT(COMMA "is stored into field with NSR base"));
+              found_nsr_alloc = true;
+              break;
+            }
+          }
+        }
+      }
+    }
+  }
+}
+
 #ifdef ASSERT
 void ConnectionGraph::verify_connection_graph(
                          GrowableArray<PointsToNode*>&   ptnodes_worklist,

src/hotspot/share/opto/escape.hpp

@@ -463,6 +463,9 @@ class ConnectionGraph: public ResourceObj {
   // Adjust scalar_replaceable state after Connection Graph is built.
   void adjust_scalar_replaceable_state(JavaObjectNode* jobj);
 
+  // Propagate NSR (Not scalar replaceable) state.
+  void find_scalar_replaceable_allocs(GrowableArray<JavaObjectNode*>& jobj_worklist);
+
   // Optimize ideal graph.
   void optimize_ideal_graph(GrowableArray<Node*>& ptr_cmp_worklist,
                             GrowableArray<MemBarStoreStoreNode*>& storestore_worklist);

test/hotspot/jtreg/compiler/escapeAnalysis/TestBrokenEA.java

@@ -0,0 +1,82 @@
+/* Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8285835
+ * @summary EA does not propagate NSR (not scalar replaceable) state.
+ * @run main/othervm -XX:-TieredCompilation -XX:-BackgroundCompilation -XX:-UseOnStackReplacement TestBrokenEA
+ */
+
+public class TestBrokenEA {
+
+    public static void main(String[] args) {
+        for (int i = 0; i < 20_000; i++) {
+            test1(true);
+            test1(false);
+            test2(true);
+            test2(false);
+        }
+    }
+
+    private static void test1(boolean flag) {
+        A[] array = new A[1];
+        if (flag) {
+            C c = new C();
+            B b = new B();
+            b.c = c;
+            A a = new A();
+            a.b = b;
+            array[0] = a;
+        }
+        A a = array[0];
+        if (a != null) {
+            a.b.c.f = 0x42;
+        }
+    }
+
+    private static void test2(boolean flag) {
+        A a = null;
+        if (flag) {
+            C c = new C();
+            B b = new B();
+            b.c = c;
+            a = new A();
+            a.b = b;
+        }
+        if (a != null) {
+            a.b.c.f = 0x42;
+        }
+    }
+
+    private static class A {
+        public B b;
+    }
+
+    private static class B {
+        public C c;
+    }
+
+    private static class C {
+        public int f;
+    }
+}