8305688: jdk build --with-memory-size=1024 broken by JDK-8305100

Reviewed-by: martin

src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavadocTokenizer.java

@@ -96,7 +96,7 @@ public class JavadocTokenizer extends JavaTokenizer {
         /**
          * StringBuilder used to extract the relevant portion of the Javadoc comment.
          */
-        private final StringBuilder sb;
+        private StringBuilder sb;
 
         /**
          * Indicates if newline is required.
@@ -166,6 +166,8 @@ public class JavadocTokenizer extends JavaTokenizer {
                 super.scanDocComment();
             } finally {
                 docComment = sb.toString();
+                sb = null;
+                offsetMap.trim();
             }
         }
     }
@@ -310,6 +312,13 @@ public class JavadocTokenizer extends JavaTokenizer {
             }
         }
 
+        /**
+         * Reduce map to minimum size.
+         */
+        void trim() {
+            map = Arrays.copyOf(map, size);
+        }
+
         /**
          * Binary search to find the entry for which the string index is less
          * than pos. Since the map is a list of pairs of integers we must make

src/jdk.compiler/share/classes/com/sun/tools/javac/parser/UnicodeReader.java

@@ -54,6 +54,11 @@ public class UnicodeReader {
      */
     private final int length;
 
+    /**
+     * Virtual position offset in the original buffer.
+     */
+    private final int offset;
+
     /**
      * Character buffer index of character currently being observed.
      */
@@ -115,7 +120,7 @@ public class UnicodeReader {
      * @param length  length of meaningful content in buffer.
      */
     protected UnicodeReader(Log log, char[] array, int length) {
-        this(log, array, 0, length);
+        this(log, array, 0, 0, length);
     }
 
     /**
@@ -127,9 +132,10 @@ public class UnicodeReader {
       * @param endPos  end of meaningful content in buffer.
       */
     @SuppressWarnings("this-escape")
-    protected UnicodeReader(Log log, char[] array, int pos, int endPos) {
+    protected UnicodeReader(Log log, char[] array, int offset, int pos, int endPos) {
         this.buffer = array;
         this.length = endPos;
+        this.offset = offset;
         this.position = pos;
         this.width = 0;
         this.character = '\0';
@@ -315,22 +321,22 @@ public class UnicodeReader {
     }
 
     /**
-     * Return the current position in the character buffer.
+     * Return the virtual position in the character buffer.
      *
-     * @return  current position in the character buffer.
+     * @return  virtual position in the character buffer.
      */
     protected int position() {
-        return position;
+        return offset + position;
     }
 
 
     /**
-     * Reset the reader to the specified position.
+     * Reset the reader to the specified virtual position.
      * Warning: Do not use when previous character was an ASCII or unicode backslash.
      * @param pos
      */
     protected void reset(int pos) {
-        position = pos;
+        position = pos - offset;
         width = 0;
         wasBackslash = false;
         wasUnicodeEscape = false;
@@ -474,7 +480,7 @@ public class UnicodeReader {
         int endPos = position;
         accept('\r');
         accept('\n');
-        return lineReader(pos, endPos);
+        return new UnicodeReader(log, buffer, offset, pos, endPos);
     }
 
     /**
@@ -487,7 +493,7 @@ public class UnicodeReader {
      * @return a new reader
      */
     protected UnicodeReader lineReader(int pos, int endPos) {
-        return new UnicodeReader(log, buffer, pos, endPos);
+        return new UnicodeReader(log, buffer, offset, pos - offset, endPos - offset);
     }
 
     /**
@@ -561,7 +567,7 @@ public class UnicodeReader {
         }
 
         // Be prepared to retreat if not a match.
-        int savedPosition = position;
+        int savedPosition = position();
 
         nextCodePoint();
 
@@ -695,7 +701,7 @@ public class UnicodeReader {
          * @param endPos  end of meaningful content in buffer.
          */
         protected PositionTrackingReader(UnicodeReader reader, int pos, int endPos) {
-            super(reader.log, reader.buffer, pos, endPos);
+            super(reader.log, reader.getRawCharacters(pos, endPos), reader.offset + pos, 0, endPos - pos);
             this.column = 0;
         }