jruby · Jul 9, 2015 · Jul 9, 2015 · Jul 9, 2015 · Jul 9, 2015 · Jul 9, 2015
diff --git a/core/src/main/java/org/jruby/ext/stringio/StringIO.java b/core/src/main/java/org/jruby/ext/stringio/StringIO.java
@@ -1126,10 +1126,11 @@ public IRubyObject write(ThreadContext context, IRubyObject arg) {
 
         enc = ptr.string.getEncoding();
         enc2 = str.getEncoding();
+        final ByteList strByteList = str.getByteList();
         if (enc != enc2 && enc != EncodingUtils.ascii8bitEncoding(runtime)
                 // this is a hack because we don't seem to handle incoming ASCII-8BIT properly in transcoder
                 && enc2 != ASCIIEncoding.INSTANCE) {
-            str = runtime.newString(EncodingUtils.strConvEnc(context, str.getByteList(), enc2, enc));
+            str = runtime.newString(EncodingUtils.strConvEnc(context, strByteList, enc2, enc));
         }
         len = str.size();
         if (len == 0) return RubyFixnum.zero(runtime);
@@ -1139,11 +1140,11 @@ public IRubyObject write(ThreadContext context, IRubyObject arg) {
             ptr.pos = olen;
         }
         if (ptr.pos == olen) {
-            EncodingUtils.encStrBufCat(runtime, ptr.string, str.getByteList(), enc);
+            EncodingUtils.encStrBufCat(runtime, ptr.string, strByteList, enc);
         } else {
             strioExtend(ptr.pos, len);
             ByteList ptrByteList = ptr.string.getByteList();
-            System.arraycopy(str.getByteList().getUnsafeBytes(), str.getByteList().getBegin(), ptrByteList.getUnsafeBytes(), ptrByteList.begin + ptr.pos, len);
+            System.arraycopy(strByteList.getUnsafeBytes(), strByteList.getBegin(), ptrByteList.getUnsafeBytes(), ptrByteList.begin() + ptr.pos, len);
         }
         ptr.string.infectBy(str);
         ptr.string.infectBy(this);

diff --git a/spec/truffle/tags/core/kernel/__dir___tags.txt b/spec/truffle/tags/core/kernel/__dir___tags.txt
@@ -1,4 +1 @@
-fails:Kernel#__dir__ returns the name of the directory containing the currently-executing file
-fails:Kernel#__dir__ when used in eval with top level binding returns the name of the directory containing the currently-executing file
-fails:Kernel#__dir__ returns the real name of the directory containing the currently-executing file
 fails:Kernel#__dir__ when used in eval with top level binding returns the real name of the directory containing the currently-executing file
diff --git a/truffle/src/main/java/org/jruby/truffle/nodes/core/ModuleNodes.java b/truffle/src/main/java/org/jruby/truffle/nodes/core/ModuleNodes.java
@@ -1207,8 +1207,8 @@ public RubyBasicObject includedModules(RubyModule module) {
 
             final List<RubyModule> modules = new ArrayList<>();
 
-            for (RubyModule included : module.parentAncestors()) {
-                if (included.isOnlyAModule()) {
+            for (RubyModule included : module.ancestors()) {
+                if (included.isOnlyAModule() && included != module) {
                     modules.add(included);
                 }
             }

diff --git a/truffle/src/main/java/org/jruby/truffle/nodes/core/StringNodes.java b/truffle/src/main/java/org/jruby/truffle/nodes/core/StringNodes.java
@@ -34,7 +34,9 @@
 import com.oracle.truffle.api.source.SourceSection;
 import com.oracle.truffle.api.utilities.BranchProfile;
 import com.oracle.truffle.api.utilities.ConditionProfile;
+
 import jnr.posix.POSIX;
+
 import org.jcodings.Encoding;
 import org.jcodings.exception.EncodingException;
 import org.jcodings.specific.ASCIIEncoding;
@@ -755,12 +757,14 @@ public ASCIIOnlyNode(RubyContext context, SourceSection sourceSection) {
         @TruffleBoundary
         @Specialization
         public boolean asciiOnly(RubyString string) {
-            if (!getByteList(string).getEncoding().isAsciiCompatible()) {
+            final ByteList byteList = StringNodes.getByteList(string);
+
+            if (!byteList.getEncoding().isAsciiCompatible()) {
                 return false;
             }
 
-            for (byte b : getByteList(string).unsafeBytes()) {
-                if ((b & 0x80) != 0) {
+            for (int i = 0; i < byteList.length(); i++) {
+                if ((byteList.get(i) & 0x80) != 0) {
                     return false;
                 }
             }

diff --git a/truffle/src/main/java/org/jruby/truffle/nodes/core/ThreadBacktraceLocationNodes.java b/truffle/src/main/java/org/jruby/truffle/nodes/core/ThreadBacktraceLocationNodes.java
@@ -44,7 +44,8 @@ protected static Activation getActivation(RubyBasicObject threadBacktraceLocatio
         return (Activation) ACTIVATION_PROPERTY.get(threadBacktraceLocation.getDynamicObject(), true);
     }
 
-    @CoreMethod(names = "absolute_path")
+    @CoreMethod(names = { "absolute_path", "path" })
+    // TODO (eregon, 8 July 2015): these two methods are slightly different (path can be relative if it is the main script)
     public abstract static class AbsolutePathNode extends UnaryCoreMethodNode {
 
         public AbsolutePathNode(RubyContext context, SourceSection sourceSection) {

diff --git a/truffle/src/main/java/org/jruby/truffle/nodes/core/TrufflePrimitiveNodes.java b/truffle/src/main/java/org/jruby/truffle/nodes/core/TrufflePrimitiveNodes.java
@@ -17,6 +17,7 @@
 import com.oracle.truffle.api.frame.MaterializedFrame;
 import com.oracle.truffle.api.source.Source;
 import com.oracle.truffle.api.source.SourceSection;
+
 import org.jruby.Ruby;
 import org.jruby.RubyGC;
 import org.jruby.ext.rbconfig.RbConfigLibrary;
@@ -35,6 +36,7 @@
 import org.jruby.truffle.runtime.core.RubyString;
 import org.jruby.truffle.runtime.hash.BucketsStrategy;
 import org.jruby.truffle.runtime.subsystems.SimpleShell;
+import org.jruby.util.ByteList;
 import org.jruby.util.Memo;
 
 import java.util.HashMap;
@@ -196,8 +198,10 @@ public DumpStringNode(RubyContext context, SourceSection sourceSection) {
         public RubyBasicObject dumpString(RubyString string) {
             final StringBuilder builder = new StringBuilder();
 
-            for (byte b : StringNodes.getByteList(string).unsafeBytes()) {
-                builder.append(String.format("\\x%02x", b));
+            final ByteList byteList = StringNodes.getByteList(string);
+
+            for (int i = 0; i < byteList.length(); i++) {
+                builder.append(String.format("\\x%02x", byteList.get(i)));
             }
 
             return createString(builder.toString());

diff --git a/truffle/src/main/java/org/jruby/truffle/nodes/rubinius/ByteArrayNodes.java b/truffle/src/main/java/org/jruby/truffle/nodes/rubinius/ByteArrayNodes.java
@@ -135,8 +135,7 @@ public LocateNode(RubyContext context, SourceSection sourceSection) {
 
         @Specialization
         public Object getByte(RubyBasicObject bytes, RubyString pattern, int start, int length) {
-            final int index = new ByteList(getBytes(bytes).unsafeBytes(), start, length)
-                    .indexOf(StringNodes.getByteList(pattern));
+            final int index = new ByteList(getBytes(bytes), start, length).indexOf(StringNodes.getByteList(pattern));
 
             if (index == -1) {
                 return nil();

diff --git a/truffle/src/main/java/org/jruby/truffle/nodes/rubinius/IOBufferPrimitiveNodes.java b/truffle/src/main/java/org/jruby/truffle/nodes/rubinius/IOBufferPrimitiveNodes.java
@@ -159,7 +159,8 @@ public IOBufferUnshiftPrimitiveNode(RubyContext context, SourceSection sourceSec
         public int unshift(VirtualFrame frame, RubyBasicObject ioBuffer, RubyString string, int startPosition) {
             setWriteSynced(ioBuffer, false);
 
-            int stringSize = StringNodes.getByteList(string).realSize() - startPosition;
+            final ByteList byteList = StringNodes.getByteList(string);
+            int stringSize = byteList.realSize() - startPosition;
             final int usedSpace = getUsed(ioBuffer);
             final int availableSpace = IOBUFFER_SIZE - usedSpace;
 
@@ -170,7 +171,7 @@ public int unshift(VirtualFrame frame, RubyBasicObject ioBuffer, RubyString stri
             ByteList storage = ByteArrayNodes.getBytes(getStorage(ioBuffer));
 
             // Data is copied here - can we do something COW?
-            System.arraycopy(StringNodes.getByteList(string).unsafeBytes(), startPosition, storage.getUnsafeBytes(), usedSpace, stringSize);
+            System.arraycopy(byteList.unsafeBytes(), byteList.begin() + startPosition, storage.getUnsafeBytes(), storage.begin() + usedSpace, stringSize);
 
             setUsed(ioBuffer, usedSpace + stringSize);
 

diff --git a/truffle/src/main/java/org/jruby/truffle/nodes/rubinius/IOPrimitiveNodes.java b/truffle/src/main/java/org/jruby/truffle/nodes/rubinius/IOPrimitiveNodes.java
@@ -238,7 +238,8 @@ public int truncate(RubyString path, int length) {
 
         @Specialization
         public int truncate(RubyString path, long length) {
-            final String pathString = RubyEncoding.decodeUTF8(StringNodes.getByteList(path).getUnsafeBytes(), StringNodes.getByteList(path).getBegin(), StringNodes.getByteList(path).getRealSize());
+            final ByteList byteList = StringNodes.getByteList(path);
+            final String pathString = RubyEncoding.decodeUTF8(byteList.getUnsafeBytes(), byteList.getBegin(), byteList.getRealSize());
             final int result = posix().truncate(pathString, length);
             if (result == -1) {
                 CompilerDirectives.transferToInterpreter();
@@ -469,15 +470,14 @@ public IOWritePrimitiveNode(RubyContext context, SourceSection sourceSection) {
         public int write(VirtualFrame frame, RubyBasicObject file, RubyString string) {
             final int fd = getDescriptor(file);
 
+            final ByteList byteList = StringNodes.getByteList(string);
+
             if (getContext().getDebugStandardOut() != null && fd == STDOUT) {
-                getContext().getDebugStandardOut().write(StringNodes.getByteList(string).unsafeBytes(), StringNodes.getByteList(string).begin(), StringNodes.getByteList(string).length());
-                return StringNodes.getByteList(string).length();
+                getContext().getDebugStandardOut().write(byteList.unsafeBytes(), byteList.begin(), byteList.length());
+                return byteList.length();
             }
 
             // We have to copy here as write starts at byte[0], and the ByteList may not
-
-            final ByteList byteList = StringNodes.getByteList(string);
-
             // TODO (eregon, 11 May 2015): review consistency under concurrent modification
             final ByteBuffer buffer = ByteBuffer.wrap(byteList.unsafeBytes(), byteList.begin(), byteList.length());
 

diff --git a/truffle/src/main/java/org/jruby/truffle/nodes/rubinius/PosixNodes.java b/truffle/src/main/java/org/jruby/truffle/nodes/rubinius/PosixNodes.java
@@ -12,8 +12,10 @@
 import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.source.SourceSection;
+
 import jnr.constants.platform.Fcntl;
 import jnr.ffi.Pointer;
+
 import org.jruby.RubyEncoding;
 import org.jruby.platform.Platform;
 import org.jruby.truffle.nodes.core.CoreClass;
@@ -24,6 +26,7 @@
 import org.jruby.truffle.runtime.control.RaiseException;
 import org.jruby.truffle.runtime.core.RubyBasicObject;
 import org.jruby.truffle.runtime.core.RubyString;
+import org.jruby.util.ByteList;
 
 import java.nio.charset.StandardCharsets;
 
@@ -314,7 +317,8 @@ public ReadlinkNode(RubyContext context, SourceSection sourceSection) {
 
         @Specialization(guards = "isRubyPointer(pointer)")
         public int readlink(RubyString path, RubyBasicObject pointer, int bufsize) {
-            final String pathString = RubyEncoding.decodeUTF8(StringNodes.getByteList(path).getUnsafeBytes(), StringNodes.getByteList(path).getBegin(), StringNodes.getByteList(path).getRealSize());
+            final ByteList byteList = StringNodes.getByteList(path);
+            final String pathString = RubyEncoding.decodeUTF8(byteList.unsafeBytes(), byteList.begin(), byteList.length());
 
             final int result = posix().readlink(pathString, PointerNodes.getPointer(pointer), bufsize);
             if (result == -1) {
@@ -369,7 +373,8 @@ public UnlinkNode(RubyContext context, SourceSection sourceSection) {
 
         @Specialization
         public int unlink(RubyString path) {
-            return posix().unlink(RubyEncoding.decodeUTF8(StringNodes.getByteList(path).getUnsafeBytes(), StringNodes.getByteList(path).getBegin(), StringNodes.getByteList(path).getRealSize()));
+            final ByteList byteList = StringNodes.getByteList(path);
+            return posix().unlink(RubyEncoding.decodeUTF8(byteList.getUnsafeBytes(), byteList.getBegin(), byteList.getRealSize()));
         }
 
     }
@@ -397,7 +402,8 @@ public UnsetenvNode(RubyContext context, SourceSection sourceSection) {
 
         @Specialization(guards = "isRubyString(name)")
         public int unsetenv(RubyBasicObject name) {
-            final String nameString = RubyEncoding.decodeUTF8(StringNodes.getByteList(name).getUnsafeBytes(), StringNodes.getByteList(name).getBegin(), StringNodes.getByteList(name).getRealSize());
+            final ByteList byteList = StringNodes.getByteList(name);
+            final String nameString = RubyEncoding.decodeUTF8(byteList.getUnsafeBytes(), byteList.getBegin(), byteList.getRealSize());
 
             return posix().unsetenv(nameString);
         }
@@ -413,7 +419,8 @@ public UtimesNode(RubyContext context, SourceSection sourceSection) {
 
         @Specialization(guards = "isRubyPointer(pointer)")
         public int utimes(RubyString path, RubyBasicObject pointer) {
-            final String pathString = RubyEncoding.decodeUTF8(StringNodes.getByteList(path).getUnsafeBytes(), StringNodes.getByteList(path).getBegin(), StringNodes.getByteList(path).getRealSize());
+            final ByteList byteList = StringNodes.getByteList(path);
+            final String pathString = RubyEncoding.decodeUTF8(byteList.getUnsafeBytes(), byteList.getBegin(), byteList.getRealSize());
 
             final int result = posix().utimes(pathString, PointerNodes.getPointer(pointer));
             if (result == -1) {

diff --git a/truffle/src/main/java/org/jruby/truffle/nodes/rubinius/StatPrimitiveNodes.java b/truffle/src/main/java/org/jruby/truffle/nodes/rubinius/StatPrimitiveNodes.java
@@ -13,14 +13,17 @@
 import com.oracle.truffle.api.frame.VirtualFrame;
 import com.oracle.truffle.api.object.HiddenKey;
 import com.oracle.truffle.api.source.SourceSection;
+
 import jnr.posix.FileStat;
+
 import org.jruby.RubyEncoding;
 import org.jruby.truffle.nodes.core.StringNodes;
 import org.jruby.truffle.nodes.objectstorage.ReadHeadObjectFieldNode;
 import org.jruby.truffle.nodes.objectstorage.WriteHeadObjectFieldNode;
 import org.jruby.truffle.runtime.RubyContext;
 import org.jruby.truffle.runtime.core.RubyBasicObject;
 import org.jruby.truffle.runtime.core.RubyString;
+import org.jruby.util.ByteList;
 
 public abstract class StatPrimitiveNodes {
 
@@ -168,7 +171,8 @@ public StatStatPrimitiveNode(RubyContext context, SourceSection sourceSection) {
         @Specialization
         public int stat(RubyBasicObject rubyStat, RubyString path) {
             final FileStat stat = posix().allocateStat();
-            final String pathString = RubyEncoding.decodeUTF8(StringNodes.getByteList(path).getUnsafeBytes(), StringNodes.getByteList(path).getBegin(), StringNodes.getByteList(path).getRealSize());
+            final ByteList byteList = StringNodes.getByteList(path);
+            final String pathString = RubyEncoding.decodeUTF8(byteList.getUnsafeBytes(), byteList.getBegin(), byteList.getRealSize());
             final int code = posix().stat(pathString, stat);
 
             if (code == 0) {

diff --git a/truffle/src/main/java/org/jruby/truffle/nodes/rubinius/StringPrimitiveNodes.java b/truffle/src/main/java/org/jruby/truffle/nodes/rubinius/StringPrimitiveNodes.java
@@ -222,21 +222,15 @@ public Object stringByteSubstring(RubyString string, int index, int length) {
 
             final int normalizedIndex = StringNodes.normalizeIndex(string, index);
 
-            if (normalizedIndex > bytes.length()) {
+            if (normalizedIndex < 0 || normalizedIndex > bytes.length()) {
                 return nil();
             }
 
-            int rangeEnd = normalizedIndex + length;
-            if (rangeEnd > bytes.length()) {
-                rangeEnd = bytes.length();
+            if (normalizedIndex + length > bytes.length()) {
+                length = bytes.length() - normalizedIndex;
             }
 
-            if (normalizedIndex + bytes.begin() < bytes.begin()) {
-                return nil();
-            }
-
-            final byte[] copiedBytes = Arrays.copyOfRange(bytes.getUnsafeBytes(), normalizedIndex + bytes.begin(), rangeEnd + bytes.begin());
-            final RubyBasicObject result = StringNodes.createString(string.getLogicalClass(), new ByteList(copiedBytes, bytes.getEncoding()));
+            final RubyBasicObject result = StringNodes.createString(string.getLogicalClass(), new ByteList(bytes, normalizedIndex, length));
 
             return taintResultNode.maybeTaint(string, result);
         }
@@ -306,14 +300,17 @@ public StringCheckNullSafePrimitiveNode(RubyContext context, SourceSection sourc
         }
 
         @Specialization
-        public boolean stringCheckNullSafe(RubyString string) {
-            for (byte b : StringNodes.getByteList(string).unsafeBytes()) {
-                if (nullByteProfile.profile(b == 0)) {
-                    return false;
+        public RubyString stringCheckNullSafe(RubyString string) {
+            final ByteList byteList = StringNodes.getByteList(string);
+
+            for (int i = 0; i < byteList.length(); i++) {
+                if (nullByteProfile.profile(byteList.get(i) == 0)) {
+                    CompilerDirectives.transferToInterpreter();
+                    throw new RaiseException(getContext().getCoreLibrary().argumentError("string contains NULL byte", this));
                 }
             }
 
-            return true;
+            return string;
         }
 
     }
@@ -470,11 +467,12 @@ public Object stringFindCharacterSingleByte(RubyString string, int offset) {
                 return nil();
             }
 
-            if (offset >= StringNodes.getByteList(string).getRealSize()) {
+            final ByteList byteList = StringNodes.getByteList(string);
+            if (offset >= byteList.getRealSize()) {
                 return nil();
             }
 
-            final RubyBasicObject ret = StringNodes.createString(string.getLogicalClass(), new ByteList(StringNodes.getByteList(string).unsafeBytes(), offset, 1));
+            final RubyBasicObject ret = StringNodes.createString(string.getLogicalClass(), new ByteList(byteList, offset, 1));
 
             return propagate(string, ret);
         }
@@ -487,19 +485,20 @@ public Object stringFindCharacter(RubyString string, int offset) {
                 return nil();
             }
 
-            if (offset >= StringNodes.getByteList(string).getRealSize()) {
+            final ByteList byteList = StringNodes.getByteList(string);
+            if (offset >= byteList.getRealSize()) {
                 return nil();
             }
 
-            final ByteList bytes = StringNodes.getByteList(string);
+            final ByteList bytes = byteList;
             final Encoding enc = bytes.getEncoding();
             final int clen = StringSupport.preciseLength(enc, bytes.getUnsafeBytes(), bytes.begin(), bytes.begin() + bytes.realSize());
 
             final RubyBasicObject ret;
             if (StringSupport.MBCLEN_CHARFOUND_P(clen)) {
-                ret = StringNodes.createString(string.getLogicalClass(), new ByteList(StringNodes.getByteList(string).unsafeBytes(), offset, clen));
+                ret = StringNodes.createString(string.getLogicalClass(), new ByteList(byteList, offset, clen));
             } else {
-                ret = StringNodes.createString(string.getLogicalClass(), new ByteList(StringNodes.getByteList(string).unsafeBytes(), offset, 1));
+                ret = StringNodes.createString(string.getLogicalClass(), new ByteList(byteList, offset, 1));
             }
 
             return propagate(string, ret);
@@ -947,7 +946,8 @@ public RubyBasicObject stringCopyFrom(RubyString string, RubyString other, int s
             int dst = dest;
             int cnt = size;
 
-            int osz = StringNodes.getByteList(other).length();
+            final ByteList otherBytes = StringNodes.getByteList(other);
+            int osz = otherBytes.length();
             if(src >= osz) return string;
             if(cnt < 0) return string;
             if(src < 0) src = 0;
@@ -956,12 +956,13 @@ public RubyBasicObject stringCopyFrom(RubyString string, RubyString other, int s
             // This bounds checks on the total capacity rather than the virtual
             // size() of the String. This allows for string adjustment within
             // the capacity without having to change the virtual size first.
-            int sz = StringNodes.getByteList(string).getUnsafeBytes().length;
+            final ByteList stringBytes = StringNodes.getByteList(string);
+            int sz = stringBytes.unsafeBytes().length - stringBytes.begin();
             if(dst >= sz) return string;
             if(dst < 0) dst = 0;
             if(cnt > sz - dst) cnt = sz - dst;
 
-            System.arraycopy(StringNodes.getByteList(other).unsafeBytes(), src, StringNodes.getByteList(string).getUnsafeBytes(), dest, cnt);
+            System.arraycopy(otherBytes.unsafeBytes(), otherBytes.begin() + src, stringBytes.getUnsafeBytes(), stringBytes.begin() + dest, cnt);
 
             return string;
         }
@@ -1073,11 +1074,11 @@ public RubyBasicObject stringPattern(RubyClass stringClass, int size, int value)
         @Specialization
         public RubyBasicObject stringPattern(RubyClass stringClass, int size, RubyString string) {
             final byte[] bytes = new byte[size];
-            final byte[] stringBytes = StringNodes.getByteList(string).unsafeBytes();
+            final ByteList byteList = StringNodes.getByteList(string);
 
-            if (StringNodes.getByteList(string).length() > 0) {
-                for (int n = 0; n < size; n += StringNodes.getByteList(string).length()) {
-                    System.arraycopy(stringBytes, 0, bytes, n, Math.min(StringNodes.getByteList(string).length(), size - n));
+            if (byteList.length() > 0) {
+                for (int n = 0; n < size; n += byteList.length()) {
+                    System.arraycopy(byteList.unsafeBytes(), byteList.begin(), bytes, n, Math.min(byteList.length(), size - n));
                 }
             }
 
@@ -1271,7 +1272,8 @@ public StringFromByteArrayPrimitiveNode(RubyContext context, SourceSection sourc
         @Specialization(guards = "isRubiniusByteArray(bytes)")
         public RubyBasicObject stringFromByteArray(RubyBasicObject bytes, int start, int count) {
             // Data is copied here - can we do something COW?
-            return createString(Arrays.copyOfRange(ByteArrayNodes.getBytes(bytes).unsafeBytes(), ByteArrayNodes.getBytes(bytes).begin() + start, ByteArrayNodes.getBytes(bytes).begin() + start + count));
+            final ByteList byteList = ByteArrayNodes.getBytes(bytes);
+            return createString(new ByteList(byteList, start, count));
         }
 
     }

diff --git a/truffle/src/main/java/org/jruby/truffle/pack/nodes/write/WriteHexStringNode.java b/truffle/src/main/java/org/jruby/truffle/pack/nodes/write/WriteHexStringNode.java
@@ -39,9 +39,6 @@ public WriteHexStringNode(RubyContext context, Endianness endianness, int length
 
     @Specialization
     public Object write(VirtualFrame frame, ByteList bytes) {
-        final byte[] b = bytes.unsafeBytes();
-        int begin = bytes.begin();
-
         int currentByte = 0;
 
         final int lengthToUse;
@@ -58,7 +55,7 @@ public Object write(VirtualFrame frame, ByteList bytes) {
             byte currentChar;
 
             if (n < bytes.length()) {
-                currentChar = b[begin + n];
+                currentChar = (byte) bytes.get(n);
             } else {
                 currentChar = 0;
             }

diff --git a/truffle/src/main/java/org/jruby/truffle/runtime/core/RubyModule.java b/truffle/src/main/java/org/jruby/truffle/runtime/core/RubyModule.java
@@ -288,9 +288,11 @@ public void prepend(Node currentNode, RubyModule module) {
         ModuleChain cur = start;
         while (mod != null && !(mod instanceof RubyClass)) {
             if (!(mod instanceof PrependMarker)) {
-                cur.insertAfter(mod.getActualModule());
-                mod.getActualModule().addDependent(this);
-                cur = cur.getParentModule();
+                if (!ModuleOperations.includesModule(this, mod.getActualModule())) {
+                    cur.insertAfter(mod.getActualModule());
+                    mod.getActualModule().addDependent(this);
+                    cur = cur.getParentModule();
+                }
             }
             mod = mod.getParentModule();
         }

diff --git a/truffle/src/main/ruby/core/kernel.rb b/truffle/src/main/ruby/core/kernel.rb
@@ -8,6 +8,12 @@
 
 module Kernel
 
+  def __dir__
+    path = caller_locations(1, 1).first.absolute_path
+    File.dirname(path)
+  end
+  module_function :__dir__
+
   def printf(*args)
     print sprintf(*args)
   end