Support Java 8 MethodParameters attribute in ijar

--
MOS_MIGRATED_REVID=105417011

3 files changed, 69 insertions, 3 deletions

diff --git a/third_party/ijar/classfile.cc b/third_party/ijar/classfile.cc
index 0a359d019b..1a11a7b3bf 100644
--- a/third_party/ijar/classfile.cc
+++ b/third_party/ijar/classfile.cc
@@ -1142,6 +1142,41 @@ struct TypeAnnotationsAttribute : Attribute {
   std::vector<TypeAnnotation*> type_annotations_;
 };
 
+// See JVMS §4.7.24
+struct MethodParametersAttribute : Attribute {
+  static MethodParametersAttribute *Read(const u1 *&p, Constant *attribute_name,
+                                         u4 attribute_length) {
+    auto attr = new MethodParametersAttribute;
+    attr->attribute_name_ = attribute_name;
+    u1 parameters_count = get_u1(p);
+    for (int ii = 0; ii < parameters_count; ++ii) {
+      MethodParameter* parameter = new MethodParameter;
+      parameter->name_ = constant(get_u2be(p));
+      parameter->access_flags_ = get_u2be(p);
+      attr->parameters_.push_back(parameter);
+    }
+    return attr;
+  }
+
+  void Write(u1 *&p) {
+    WriteProlog(p, -1);
+    u1 *payload_start = p - 4;
+    put_u1(p, parameters_.size());
+    for (MethodParameter* parameter : parameters_) {
+      put_u2be(p, parameter->name_->slot());
+      put_u2be(p, parameter->access_flags_);
+    }
+    put_u4be(payload_start, p - 4 - payload_start);  // backpatch length
+  }
+
+  struct MethodParameter {
+    Constant *name_;
+    u2 access_flags_;
+  };
+
+  std::vector<MethodParameter*> parameters_;
+};
+
 struct GeneralAttribute : Attribute {
   static GeneralAttribute* Read(const u1 *&p, Constant *attribute_name,
                                 u4 attribute_length) {
@@ -1344,10 +1379,11 @@ void HasAttrs::ReadAttrs(const u1 *&p) {
                                                   attribute_length));
     } else if (attr_name == "RuntimeVisibleTypeAnnotations" ||
                attr_name == "RuntimeInvisibleTypeAnnotations") {
-      // JSR 308: annotations on types. JDK 7 has no use for these yet, but the
-      // Checkers Framework relies on them.
       attributes.push_back(TypeAnnotationsAttribute::Read(p, attribute_name,
                                                           attribute_length));
+    } else if (attr_name == "MethodParameters") {
+      attributes.push_back(
+          MethodParametersAttribute::Read(p, attribute_name, attribute_length));
     } else {
       // Skip over unknown attributes with a warning.  The JVM spec
       // says this is ok, so long as we handle the mandatory attributes.
diff --git a/third_party/ijar/test/ijar_test.sh b/third_party/ijar/test/ijar_test.sh
index 848dbddd53..174d35cab1 100755
--- a/third_party/ijar/test/ijar_test.sh
+++ b/third_party/ijar/test/ijar_test.sh
@@ -1,6 +1,6 @@
 #!/bin/bash -eu
 #
-# Copyright 2015 Google Inc. All rights reserved.
+# Copyright 2015 The Bazel Authors. All rights reserved.
 # 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
@@ -66,6 +66,8 @@ TYPEANN2_IJAR=$TEST_TMPDIR/typeannotations2_interface.jar
 TYPEANN2_JAVA=$IJAR_SRCDIR/test/TypeAnnotationTest2.java
 INVOKEDYNAMIC_JAR=$IJAR_SRCDIR/test/libinvokedynamic.jar
 INVOKEDYNAMIC_IJAR=$TEST_TMPDIR/invokedynamic_interface.jar
+METHODPARAM_JAR=$IJAR_SRCDIR/test/libmethodparameters.jar
+METHODPARAM_IJAR=$TEST_TMPDIR/methodparameters_interface.jar
 
 #### Setup
 
@@ -494,4 +496,12 @@ EOF
   cmp one/one-ijar.jar three/three-ijar.jar
 }
 
+function test_method_parameters_attribute() {
+  # Check that Java 8 MethodParameters attributes are preserved
+  $IJAR $METHODPARAM_JAR $METHODPARAM_IJAR || fail "ijar failed"
+  $JAVAP -classpath $METHODPARAM_IJAR -v methodparameters.Test >& $TEST_log \
+    || fail "javap failed"
+  expect_log "MethodParameters" "MethodParameters not preserved!"
+}
+
 run_suite "ijar tests"
diff --git a/third_party/ijar/test/methodparameters/Test.java b/third_party/ijar/test/methodparameters/Test.java
new file mode 100644
index 0000000000..7843cd8a7c
--- /dev/null
+++ b/third_party/ijar/test/methodparameters/Test.java
@@ -0,0 +1,20 @@
+// Copyright 2015 The Bazel Authors. All rights reserved.
+//
+// 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.
+
+package methodparameters;
+
+public class Test {
+  public static void foo(String fooParam) {}
+  public static void bar(final String barParam) {}
+}