From: Nicolas Geoffray <ngeoffray@google.com>
Date: Thu, 2 Mar 2017 16:14:53 +0000 (+0000)
Subject: Don't inline methods that throw in graph with irreducible loops.
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=1eede6ae9b08d305d0c1123284ff958373916474;p=android-x86%2Fart.git

Don't inline methods that throw in graph with irreducible loops.

Re-computing the loop information is not supported in graphs
with irreducible loops, as it is not deterministic, and the
loop header of a loop could change. That would lead to having the
suspend check in the wrong block.

Test: test-art-host
Test: 641-irreducible-inline
bug: 35757766
Change-Id: I6a435885461fbeca035e4f5d94f055fc3262adca
---

diff --git a/compiler/optimizing/inliner.cc b/compiler/optimizing/inliner.cc
index 3e340908b..14437dea3 100644
--- a/compiler/optimizing/inliner.cc
+++ b/compiler/optimizing/inliner.cc
@@ -1380,6 +1380,13 @@ bool HInliner::TryBuildAndInlineHelper(HInvoke* invoke_instruction,
                        << " could not be inlined because one branch always throws and"
                        << " caller does not have an exit block";
         return false;
+      } else if (graph_->HasIrreducibleLoops()) {
+        // TODO(ngeoffray): Support re-computing loop information to graphs with
+        // irreducible loops?
+        VLOG(compiler) << "Method " << callee_dex_file.PrettyMethod(method_index)
+                       << " could not be inlined because one branch always throws and"
+                       << " caller has irreducible loops";
+        return false;
       }
     } else {
       has_one_return = true;
diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index 62c89100e..020e4463d 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -2179,6 +2179,9 @@ HInstruction* HGraph::InlineInto(HGraph* outer_graph, HInvoke* invoke) {
       }
     }
     if (rerun_loop_analysis) {
+      DCHECK(!outer_graph->HasIrreducibleLoops())
+          << "Recomputing loop information in graphs with irreducible loops "
+          << "is unsupported, as it could lead to loop header changes";
       outer_graph->ClearLoopInformation();
       outer_graph->ClearDominanceInformation();
       outer_graph->BuildDominatorTree();
diff --git a/test/641-irreducible-inline/expected.txt b/test/641-irreducible-inline/expected.txt
new file mode 100644
index 000000000..d81cc0710
--- /dev/null
+++ b/test/641-irreducible-inline/expected.txt
@@ -0,0 +1 @@
+42
diff --git a/test/641-irreducible-inline/info.txt b/test/641-irreducible-inline/info.txt
new file mode 100644
index 000000000..ec6d0d25c
--- /dev/null
+++ b/test/641-irreducible-inline/info.txt
@@ -0,0 +1,2 @@
+Regression test for optimizing in the presence of
+inlining a method that throws in an irreducible loop
diff --git a/test/641-irreducible-inline/smali/IrreducibleLoop.smali b/test/641-irreducible-inline/smali/IrreducibleLoop.smali
new file mode 100644
index 000000000..3e6c1f1ba
--- /dev/null
+++ b/test/641-irreducible-inline/smali/IrreducibleLoop.smali
@@ -0,0 +1,54 @@
+# Copyright (C) 2017 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+.class public LIrreducibleLoop;
+
+.super Ljava/lang/Object;
+
+.method public static simpleLoop(I)I
+   .registers 3
+   const/16 v0, 42
+   if-eqz p0, :loop_entry
+   goto :other_loop_pre_entry
+
+   # The then part: beginning of the irreducible loop.
+   :loop_entry
+   if-nez p0, :exit
+   invoke-static {v0},LIrreducibleLoop;->foo(I)V
+   :other_loop_entry
+   goto :loop_entry
+
+   # The else part.
+   :other_loop_pre_entry
+   if-eqz p0, :other_loop_entry
+   invoke-static {v0},LIrreducibleLoop;->foo(I)V
+   goto :other_loop_entry
+
+   :exit
+   return v0
+.end method
+
+.method public static foo(I)V
+   .registers 3
+   const/16 v0, 0
+   sget-boolean v1,LIrreducibleLoop;->doThrow:Z
+   if-eqz v1, :exit
+   # Inlining a method that throws requires re-computing loop information
+   # which is unsupported when the caller has an irreducible loop.
+   throw v0
+   :exit
+   return-void
+.end method
+
+.field public static doThrow:Z
diff --git a/test/641-irreducible-inline/src/Main.java b/test/641-irreducible-inline/src/Main.java
new file mode 100644
index 000000000..53244f7c3
--- /dev/null
+++ b/test/641-irreducible-inline/src/Main.java
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.lang.reflect.Method;
+
+public class Main {
+  // Workaround for b/18051191.
+  class InnerClass {}
+
+  public static void main(String[] args) throws Exception {
+    Class<?> c = Class.forName("IrreducibleLoop");
+    Method m = c.getMethod("simpleLoop", int.class);
+    Object[] arguments = { 42 };
+    System.out.println(m.invoke(null, arguments));
+  }
+}