Ensure inlined static calls perform clinit checks in Optimizing.
Calls to static methods have implicit class initialization
(clinit) checks of the method's declaring class in
Optimizing. However, when such a static call is inlined,
the implicit clinit check vanishes, possibly leading to an
incorrect behavior.
To ensure that inlining static methods does not change the
behavior of a program, add explicit class initialization
checks (art::HClinitCheck) as well as load class
instructions (art::HLoadClass) as last input of static
calls (art::HInvokeStaticOrDirect) in Optimizing' control
flow graphs, when the declaring class is reachable and not
known to be already initialized. Then when considering the
inlining of a static method call, proceed only if the method
has no implicit clinit check requirement.
The added explicit clinit checks are already removed by the
art::PrepareForRegisterAllocation visitor. This CL also
extends this visitor to turn explicit clinit checks from
static invokes into implicit ones after the inlining step,
by removing the added art::HLoadClass nodes mentioned
hereinbefore.
Change-Id: I9ba452b8bd09ae1fdd9a3797ef556e3e7e19c651
diff --git a/test/478-checker-clinit-check-pruning/src/Main.java b/test/478-checker-clinit-check-pruning/src/Main.java
new file mode 100644
index 0000000..5370f86
--- /dev/null
+++ b/test/478-checker-clinit-check-pruning/src/Main.java
@@ -0,0 +1,200 @@
+/*
+ * Copyright (C) 2015 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 {
+
+ /*
+ * Ensure an inlined static invoke explicitly triggers the
+ * initialization check of the called method's declaring class, and
+ * that the corresponding load class instruction does not get
+ * removed before register allocation & code generation.
+ */
+
+ // CHECK-START: void Main.invokeStaticInlined() builder (after)
+ // CHECK-DAG: [[LoadClass:l\d+]] LoadClass
+ // CHECK-DAG: [[ClinitCheck:l\d+]] ClinitCheck [ [[LoadClass]] ]
+ // CHECK-DAG: InvokeStaticOrDirect [ [[ClinitCheck]] ]
+
+ // CHECK-START: void Main.invokeStaticInlined() inliner (after)
+ // CHECK-DAG: [[LoadClass:l\d+]] LoadClass
+ // CHECK-DAG: [[ClinitCheck:l\d+]] ClinitCheck [ [[LoadClass]] ]
+
+ // CHECK-START: void Main.invokeStaticInlined() inliner (after)
+ // CHECK-NOT: InvokeStaticOrDirect
+
+ // The following checks ensure the clinit check instruction added by
+ // the builder is pruned by the PrepareForRegisterAllocation, while
+ // the load class instruction is preserved. As the control flow
+ // graph is not dumped after (nor before) this step, we check the
+ // CFG as it is before the next pass (liveness analysis) instead.
+
+ // CHECK-START: void Main.invokeStaticInlined() liveness (before)
+ // CHECK-DAG: LoadClass
+
+ // CHECK-START: void Main.invokeStaticInlined() liveness (before)
+ // CHECK-NOT: ClinitCheck
+ // CHECK-NOT: InvokeStaticOrDirect
+
+ static void invokeStaticInlined() {
+ ClassWithClinit1.$opt$inline$StaticMethod();
+ }
+
+ static class ClassWithClinit1 {
+ static {
+ System.out.println("Main$ClassWithClinit1's static initializer");
+ }
+
+ static void $opt$inline$StaticMethod() {
+ }
+ }
+
+ /*
+ * Ensure a non-inlined static invoke eventually has an implicit
+ * initialization check of the called method's declaring class.
+ */
+
+ // CHECK-START: void Main.invokeStaticNotInlined() builder (after)
+ // CHECK-DAG: [[LoadClass:l\d+]] LoadClass
+ // CHECK-DAG: [[ClinitCheck:l\d+]] ClinitCheck [ [[LoadClass]] ]
+ // CHECK-DAG: InvokeStaticOrDirect [ [[ClinitCheck]] ]
+
+ // CHECK-START: void Main.invokeStaticNotInlined() inliner (after)
+ // CHECK-DAG: [[LoadClass:l\d+]] LoadClass
+ // CHECK-DAG: [[ClinitCheck:l\d+]] ClinitCheck [ [[LoadClass]] ]
+ // CHECK-DAG: InvokeStaticOrDirect [ [[ClinitCheck]] ]
+
+ // The following checks ensure the clinit check and load class
+ // instructions added by the builder are pruned by the
+ // PrepareForRegisterAllocation. As the control flow graph is not
+ // dumped after (nor before) this step, we check the CFG as it is
+ // before the next pass (liveness analysis) instead.
+
+ // CHECK-START: void Main.invokeStaticNotInlined() liveness (before)
+ // CHECK-DAG: InvokeStaticOrDirect
+
+ // CHECK-START: void Main.invokeStaticNotInlined() liveness (before)
+ // CHECK-NOT: LoadClass
+ // CHECK-NOT: ClinitCheck
+
+ static void invokeStaticNotInlined() {
+ ClassWithClinit2.staticMethod();
+ }
+
+ static class ClassWithClinit2 {
+ static {
+ System.out.println("Main$ClassWithClinit2's static initializer");
+ }
+
+ static boolean doThrow = false;
+
+ static void staticMethod() {
+ if (doThrow) {
+ // Try defeating inlining.
+ throw new Error();
+ }
+ }
+ }
+
+ /*
+ * Ensure an inlined call to a static method whose declaring class
+ * is statically known to have been initialized does not require an
+ * explicit clinit check.
+ */
+
+ // CHECK-START: void Main$ClassWithClinit3.invokeStaticInlined() builder (after)
+ // CHECK-DAG: InvokeStaticOrDirect
+
+ // CHECK-START: void Main$ClassWithClinit3.invokeStaticInlined() builder (after)
+ // CHECK-NOT: LoadClass
+ // CHECK-NOT: ClinitCheck
+
+ // CHECK-START: void Main$ClassWithClinit3.invokeStaticInlined() inliner (after)
+ // CHECK-NOT: LoadClass
+ // CHECK-NOT: ClinitCheck
+ // CHECK-NOT: InvokeStaticOrDirect
+
+ static class ClassWithClinit3 {
+ static void invokeStaticInlined() {
+ // The invocation of invokeStaticInlined triggers the
+ // initialization of ClassWithClinit3, meaning that the
+ // hereinbelow call to $opt$inline$StaticMethod does not need a
+ // clinit check.
+ $opt$inline$StaticMethod();
+ }
+
+ static {
+ System.out.println("Main$ClassWithClinit3's static initializer");
+ }
+
+ static void $opt$inline$StaticMethod() {
+ }
+ }
+
+ /*
+ * Ensure an non-inlined call to a static method whose declaring
+ * class is statically known to have been initialized does not
+ * require an explicit clinit check.
+ */
+
+ // CHECK-START: void Main$ClassWithClinit4.invokeStaticNotInlined() builder (after)
+ // CHECK-DAG: InvokeStaticOrDirect
+
+ // CHECK-START: void Main$ClassWithClinit4.invokeStaticNotInlined() builder (after)
+ // CHECK-NOT: LoadClass
+ // CHECK-NOT: ClinitCheck
+
+ // CHECK-START: void Main$ClassWithClinit4.invokeStaticNotInlined() inliner (after)
+ // CHECK-DAG: InvokeStaticOrDirect
+
+ // CHECK-START: void Main$ClassWithClinit4.invokeStaticNotInlined() inliner (after)
+ // CHECK-NOT: LoadClass
+ // CHECK-NOT: ClinitCheck
+
+ static class ClassWithClinit4 {
+ static void invokeStaticNotInlined() {
+ // The invocation of invokeStaticNotInlined triggers the
+ // initialization of ClassWithClinit4, meaning that the
+ // hereinbelow call to staticMethod does not need a clinit
+ // check.
+ staticMethod();
+ }
+
+ static {
+ System.out.println("Main$ClassWithClinit4's static initializer");
+ }
+
+ static boolean doThrow = false;
+
+ static void staticMethod() {
+ if (doThrow) {
+ // Try defeating inlining.
+ throw new Error();
+ }
+ }
+ }
+
+ // TODO: Add a test for the case of a static method whose declaring
+ // class type index is not available (i.e. when `storage_index`
+ // equals `DexFile::kDexNoIndex` in
+ // art::HGraphBuilder::BuildInvoke).
+
+ public static void main(String[] args) {
+ invokeStaticInlined();
+ invokeStaticNotInlined();
+ ClassWithClinit3.invokeStaticInlined();
+ ClassWithClinit4.invokeStaticNotInlined();
+ }
+}