Generate code for loops formed with the new builder

Adapt the existing counted loop analysis and range/null check
elimination code to work with the new loop building heuristics.
Cleaned up the old ad-hoc loop builder.

Suspend polling is enabled by default for loops. The backward chaining
cell will be used in self-verification and profiling mode.

If the loop includes accesses to resolved fields/classes, abort code
generation for now and revert to the basic acyclic trace. Added
tests/090-loop-formation to make sure the JIT won't choke on such
instructions.

Change-Id: Idbc57df0a745be3b692f68c1acb6d4861c537f75

3 files changed, 64 insertions, 0 deletions

diff --git a/tests/090-loop-formation/expected.txt b/tests/090-loop-formation/expected.txt
new file mode 100644
index 000000000..b7e0bb3d1
--- /dev/null
+++ b/tests/090-loop-formation/expected.txt
@@ -0,0 +1,5 @@
+counter1 is 0
+counter2 is 32767
+counter3 is 32767
+counter4 is 0
+counter5 is 65534
diff --git a/tests/090-loop-formation/info.txt b/tests/090-loop-formation/info.txt
new file mode 100644
index 000000000..98d1d4bef
--- /dev/null
+++ b/tests/090-loop-formation/info.txt
@@ -0,0 +1,3 @@
+Test loop formation heuristics and code generation. Basically the problem to
+catch here is to make sure that some never-exercised code blocks are included
+in the loop region, and the JIT compiler won't choke on unresolved fields.
diff --git a/tests/090-loop-formation/src/Main.java b/tests/090-loop-formation/src/Main.java
new file mode 100644
index 000000000..7c16667ff
--- /dev/null
+++ b/tests/090-loop-formation/src/Main.java
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2011 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.
+ */
+
+/*
+ * Create two versions of loops where the unresolved field is on either the
+ * taken or the non-taken path to make sure that the loop detection code bails
+ * on unresolved fields.
+ */
+public class Main {
+    static int counter1;
+    static int counter2;
+    static int counter3;
+    static int counter4;
+    static int counter5;
+
+    public static void main(String[] args) {
+        /* counter1 is not resolved */
+        for (int i = 0; i < 32767; i++) {
+            if (i < 0) {
+                counter1++;
+            } else {
+                counter2++;
+            }
+            counter5++;
+        }
+
+        /* counter4 is not resolved */
+        for (int i = 0; i < 32767; i++) {
+            if (i >= 0) {
+                counter3++;
+            } else {
+                counter4++;
+            }
+            counter5++;
+        }
+
+        System.out.println("counter1 is " + counter1);
+        System.out.println("counter2 is " + counter2);
+        System.out.println("counter3 is " + counter3);
+        System.out.println("counter4 is " + counter4);
+        System.out.println("counter5 is " + counter5);
+    }
+}