Fix ARM64 Baker's read barrier fast path for ArraySet.
Do not exhaust the pool of scratch (temporary) registers
gratuitously when emitting an instrumented array load with a
large constant index.
Bug: 26817006
Bug: 12687968
Change-Id: I65a4fe676aa3c9e2c8d7e26195d9af6432c83ff9
diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index e20e044..cfdf6b1 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -4880,20 +4880,18 @@
static_assert(
sizeof(mirror::HeapReference<mirror::Object>) == sizeof(int32_t),
"art::mirror::HeapReference<art::mirror::Object> and int32_t have different sizes.");
- temp2 = temps.AcquireW();
// /* HeapReference<Object> */ ref =
// *(obj + offset + index * sizeof(HeapReference<Object>))
- MemOperand source = HeapOperand(obj);
+ const size_t shift_amount = Primitive::ComponentSizeShift(type);
if (index.IsConstant()) {
- uint32_t computed_offset =
- offset + (Int64ConstantFrom(index) << Primitive::ComponentSizeShift(type));
- source = HeapOperand(obj, computed_offset);
+ uint32_t computed_offset = offset + (Int64ConstantFrom(index) << shift_amount);
+ Load(type, ref_reg, HeapOperand(obj, computed_offset));
} else {
+ temp2 = temps.AcquireW();
__ Add(temp2, obj, offset);
- source = HeapOperand(temp2, XRegisterFrom(index), LSL, Primitive::ComponentSizeShift(type));
+ Load(type, ref_reg, HeapOperand(temp2, XRegisterFrom(index), LSL, shift_amount));
+ temps.Release(temp2);
}
- Load(type, ref_reg, source);
- temps.Release(temp2);
} else {
// /* HeapReference<Object> */ ref = *(obj + offset)
MemOperand field = HeapOperand(obj, offset);
diff --git a/test/572-checker-array-get-regression/expected.txt b/test/572-checker-array-get-regression/expected.txt
new file mode 100644
index 0000000..c08d783
--- /dev/null
+++ b/test/572-checker-array-get-regression/expected.txt
@@ -0,0 +1 @@
+1048575
diff --git a/test/572-checker-array-get-regression/info.txt b/test/572-checker-array-get-regression/info.txt
new file mode 100644
index 0000000..023d5b0
--- /dev/null
+++ b/test/572-checker-array-get-regression/info.txt
@@ -0,0 +1,3 @@
+Regression test for the ARM64 Baker's read barrier fast path compiler
+instrumentatin of array loads with a large constant index, where we
+used to require too many scratch (temporary) registers.
diff --git a/test/572-checker-array-get-regression/src/Main.java b/test/572-checker-array-get-regression/src/Main.java
new file mode 100644
index 0000000..bc13af9
--- /dev/null
+++ b/test/572-checker-array-get-regression/src/Main.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+public class Main {
+
+ public static void main(String[] args) {
+ System.out.println(test().intValue());
+ }
+
+ /// CHECK-START: java.lang.Integer Main.test() ssa_builder (after)
+ /// CHECK-DAG: <<Method:j\d+>> CurrentMethod
+ /// CHECK-DAG: <<Const2P20:i\d+>> IntConstant 1048576
+ /// CHECK-DAG: <<ConstM1:i\d+>> IntConstant -1
+ /// CHECK-DAG: <<Array:l\d+>> NewArray [<<Const2P20>>,<<Method>>]
+ /// CHECK-DAG: <<NullCheck1:l\d+>> NullCheck [<<Array>>]
+ /// CHECK-DAG: <<Length1:i\d+>> ArrayLength [<<NullCheck1>>]
+ /// CHECK-DAG: <<Index:i\d+>> Add [<<Length1>>,<<ConstM1>>]
+ /// CHECK-DAG: <<NullCheck2:l\d+>> NullCheck [<<Array>>]
+ /// CHECK-DAG: <<Length2:i\d+>> ArrayLength [<<NullCheck2>>]
+ /// CHECK-DAG: <<BoundsCheck:i\d+>> BoundsCheck [<<Index>>,<<Length2>>]
+ /// CHECK-DAG: <<LastElement:l\d+>> ArrayGet [<<NullCheck2>>,<<BoundsCheck>>]
+ /// CHECK-DAG: Return [<<LastElement>>]
+
+ /// CHECK-START: java.lang.Integer Main.test() register (before)
+ /// CHECK-DAG: <<Method:j\d+>> CurrentMethod
+ /// CHECK-DAG: <<Const2P20:i\d+>> IntConstant 1048576
+ /// CHECK-DAG: <<Const2P20M1:i\d+>> IntConstant 1048575
+ /// CHECK-DAG: <<Array:l\d+>> NewArray [<<Const2P20>>,<<Method>>]
+ /// CHECK-DAG: <<LastElement:l\d+>> ArrayGet [<<Array>>,<<Const2P20M1>>]
+ /// CHECK-DAG: Return [<<LastElement>>]
+
+ public static Integer test() {
+ Integer[] integers = new Integer[1024 * 1024];
+ initIntegerArray(integers);
+ // Array load with a large constant index (after constant folding
+ // and bounds check elimination).
+ Integer last_integer = integers[integers.length - 1];
+ return last_integer;
+ }
+
+ public static void initIntegerArray(Integer[] integers) {
+ for (int i = 0; i < integers.length; ++i) {
+ integers[i] = new Integer(i);
+ }
+ }
+
+}