Use 'int' instead of Position.

By doing so we get 5-7% of performance in running JUnit tests. R=brianwilkerson@google.com BUG= TEST= Review URL: https://chromiumcodereview.appspot.com//10704180 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@9596 260f80e4-7a28-3924-810f-c04153c831b5
2012-07-12 16:10:10 +00:00
parent ef7cbbbbe7
commit bb13f021a4
9 changed files with 106 additions and 199 deletions
@@ -7,7 +7,6 @@ package com.google.dart.compiler;
 import com.google.dart.compiler.common.HasSourceInfo;
 import com.google.dart.compiler.common.SourceInfo;
 import com.google.dart.compiler.parser.DartScanner.Location;
-import com.google.dart.compiler.parser.DartScanner.Position;

 /**
 * Information about a compilation error.
@@ -109,19 +108,11 @@ public class DartCompilationError {
    this.errorCode = errorCode;
    this.message = String.format(errorCode.getMessage(), arguments);
    if (location != null) {
-      Position begin = location.getBegin();
-      if (begin != null) {
-        offset = begin.getPos();
-        lineNumber = begin.getLine();
-        columnNumber = begin.getCol();
-      }
-      Position end = location.getEnd();
-      if (end != null) {
-        length = end.getPos() - offset;
-        if (length < 0) {
-          length = 0;
-        }
-      }
+      offset = location.getBegin();
+      SourceInfo sourceInfo = new SourceInfo(source, offset, 0);
+      lineNumber = sourceInfo.getLine();
+      columnNumber = sourceInfo.getColumn();
+      length = location.getEnd() - offset;
    }
  }

@@ -161,6 +161,9 @@ public final class SourceInfo implements Serializable {
    }

    int getLineOffset(int line) {
+      if (line < 0) {
+        return 0;
+      }
      return lineOffsets.get(line);
    }

@@ -190,25 +190,24 @@ abstract class AbstractParser {
        && keyword.equals(getPeekTokenValue(n));
  }

-  protected DartScanner.Position position() {
+  protected int position() {
    DartScanner.Location tokenLocation = ctx.getTokenLocation();
-    return tokenLocation != null ? tokenLocation.getBegin()
-        : new DartScanner.Position(0, 1, 1);
+    return tokenLocation != null ? tokenLocation.getBegin() : 0;
  }

  /**
   * Report a syntax error, unless an error has already been reported at the
   * given or a later position.
   */
-  protected void reportError(DartScanner.Position position,
+  protected void reportError(int position,
                             ErrorCode errorCode, Object... arguments) {
    DartScanner.Location location = ctx.getTokenLocation();
-    if (location.getBegin().getPos() <= lastErrorPosition) {
+    if (location.getBegin() <= lastErrorPosition) {
      return;
    }
    DartCompilationError dartError = new DartCompilationError(ctx.getSource(),
        location, errorCode, arguments);
-    lastErrorPosition = position.getPos();
+    lastErrorPosition = position;
    ctx.error(dartError);
  }

@@ -217,11 +216,11 @@ abstract class AbstractParser {
   * uses that to prevent logging more than one error at that position. This
   * method actually uses the passed position to create the error event.
   */
-  protected void reportErrorAtPosition(DartScanner.Position startPosition,
-                                       DartScanner.Position endPosition,
+  protected void reportErrorAtPosition(int startPosition,
+                                       int endPosition,
                                       ErrorCode errorCode, Object... arguments) {
    DartScanner.Location location = ctx.getTokenLocation();
-    if (location.getBegin().getPos() <= lastErrorPosition) {
+    if (location.getBegin() <= lastErrorPosition) {
      return;
    }
    DartCompilationError dartError = new DartCompilationError(ctx.getSource(),
@@ -229,7 +228,7 @@ abstract class AbstractParser {
    ctx.error(dartError);
  }

-  protected void reportUnexpectedToken(DartScanner.Position position,
+  protected void reportUnexpectedToken(int position,
                                       Token expected, Token actual) {
    if (expected == Token.EOS) {
      reportError(position, ParserErrorCode.EXPECTED_EOS, actual);
@@ -55,7 +55,7 @@ public abstract class CompletionHooksParserBase extends AbstractParser {
     * productions at fault. Called from begin()
     */
    public boolean assertProgress() {
-      int currentPosition = position().getPos();
+      int currentPosition = position();
      if (currentPosition > maxPositionRange) {
        minPositionRange = maxPositionRange;
        maxPositionRange = currentPosition;
@@ -96,7 +96,6 @@ import com.google.dart.compiler.ast.LibraryUnit;
 import com.google.dart.compiler.ast.Modifiers;
 import com.google.dart.compiler.metrics.CompilerMetrics;
 import com.google.dart.compiler.parser.DartScanner.Location;
-import com.google.dart.compiler.parser.DartScanner.Position;
 import com.google.dart.compiler.util.Lists;

 import java.io.IOException;
@@ -122,7 +121,7 @@ public class DartParser extends CompletionHooksParserBase {
  private final Set<Integer> errorHistory = new HashSet<Integer>();
  private boolean isParsingInterface;
  private boolean isTopLevelAbstract;
-  private DartScanner.Position topLevelAbstractModifierPosition;
+  private int topLevelAbstractModifierPosition;
  private boolean isParsingClass;
  private int errorCount = 0;
  
@@ -304,7 +303,7 @@ public class DartParser extends CompletionHooksParserBase {
        isParsingClass = isParsingInterface = false;
        // Check for ABSTRACT_KEYWORD.
        isTopLevelAbstract = false;
-        topLevelAbstractModifierPosition = null;
+        topLevelAbstractModifierPosition = 0;
        if (optionalPseudoKeyword(ABSTRACT_KEYWORD)) {
          isTopLevelAbstract = true;
          topLevelAbstractModifierPosition = position();
@@ -332,7 +331,7 @@ public class DartParser extends CompletionHooksParserBase {
          unit.getTopLevelNodes().add(node);
          // Only "class" can be top-level abstract element.
          if (isTopLevelAbstract && !isParsingClass) {
-            Position abstractPositionEnd = topLevelAbstractModifierPosition.getAdvancedColumns(ABSTRACT_KEYWORD.length());
+            int abstractPositionEnd = topLevelAbstractModifierPosition + ABSTRACT_KEYWORD.length();
            Location location = new Location(topLevelAbstractModifierPosition, abstractPositionEnd);
            reportError(new DartCompilationError(source, location,
                ParserErrorCode.ABSTRACT_TOP_LEVEL_ELEMENT));
@@ -1927,7 +1926,7 @@ public class DartParser extends CompletionHooksParserBase {
    } else if (token.isAssignmentOperator()) {
      ensureAssignable(result);
      consume(token);
-      int tokenOffset = ctx.getTokenLocation().getBegin().getPos();
+      int tokenOffset = ctx.getTokenLocation().getBegin();
      result = done(new DartBinaryExpression(token, tokenOffset, result, parseExpression()));
    } else {
      done(null);
@@ -1959,7 +1958,7 @@ public class DartParser extends CompletionHooksParserBase {
   if (token.isAssignmentOperator()) {
      ensureAssignable(result);
      consume(token);
-      int tokenOffset = ctx.getTokenLocation().getBegin().getPos();
+      int tokenOffset = ctx.getTokenLocation().getBegin();
      result = done(new DartBinaryExpression(token, tokenOffset, result, parseExpressionWithoutCascade()));
    } else {
      done(null);
@@ -2026,7 +2025,7 @@ public class DartParser extends CompletionHooksParserBase {
    if (token.isAssignmentOperator()) {
      ensureAssignable(result);
      consume(token);
-      int tokenOffset = ctx.getTokenLocation().getBegin().getPos();
+      int tokenOffset = ctx.getTokenLocation().getBegin();
      result = doneWithoutConsuming(new DartBinaryExpression(token, tokenOffset, result, parseExpressionWithoutCascade()));
    }
    return result;
@@ -2043,7 +2042,7 @@ public class DartParser extends CompletionHooksParserBase {
    DartExpression result = parseExpression();
    // Must keep in sync with @Terminals above
    while (optional(Token.COMMA)) {
-      int tokenOffset = ctx.getTokenLocation().getBegin().getPos();
+      int tokenOffset = ctx.getTokenLocation().getBegin();
      result = new DartBinaryExpression(Token.COMMA, tokenOffset, result, parseExpression());
      if (match(Token.COMMA)) {
        result = doneWithoutConsuming(result);
@@ -2107,10 +2106,10 @@ public class DartParser extends CompletionHooksParserBase {
    DartExpression result = lastResult;
    for (int level = peek(0).getPrecedence(); level >= precedence; level--) {
      while (peek(0).getPrecedence() == level) {
-        Position prevPositionStart = ctx.getTokenLocation().getBegin();
-        Position prevPositionEnd = ctx.getTokenLocation().getEnd();
+        int prevPositionStart = ctx.getTokenLocation().getBegin();
+        int prevPositionEnd = ctx.getTokenLocation().getEnd();
        Token token = next();
-        int tokenOffset = ctx.getTokenLocation().getBegin().getPos();
+        int tokenOffset = ctx.getTokenLocation().getBegin();
        if (lastResult instanceof DartSuperExpression
            && (token == Token.AND || token == Token.OR)) {
          reportErrorAtPosition(prevPositionStart, prevPositionEnd,
@@ -2120,7 +2119,7 @@ public class DartParser extends CompletionHooksParserBase {
        if (token == Token.IS) {
          beginTypeExpression();
          if (optional(Token.NOT)) {
-            int notOffset = ctx.getTokenLocation().getBegin().getPos();
+            int notOffset = ctx.getTokenLocation().getBegin();
            beginTypeExpression();
            DartTypeExpression typeExpression = done(new DartTypeExpression(parseTypeAnnotation()));
            right = done(new DartUnaryExpression(Token.NOT, notOffset, typeExpression, true));
@@ -2621,7 +2620,7 @@ public class DartParser extends CompletionHooksParserBase {
    if (token.isCountOperator()) {
      ensureAssignable(result);
      consume(token);
-      int tokenOffset = ctx.getTokenLocation().getBegin().getPos();
+      int tokenOffset = ctx.getTokenLocation().getBegin();
      result = doneWithoutConsuming(new DartUnaryExpression(token, tokenOffset, result, false));
    }

@@ -3286,12 +3285,12 @@ public class DartParser extends CompletionHooksParserBase {
          reportErrorWithoutAdvancing(ParserErrorCode.UNEXPECTED_TOKEN);
          break;
        }
-        int startPosition = position().getPos();
+        int startPosition = position();
        DartStatement newStatement = parseStatement();
        if (newStatement == null) {
          break;
        }
-        if (startPosition == position().getPos()) {
+        if (startPosition == position()) {
          // The parser is not making progress.
          Set<Token> terminals = this.collectTerminalAnnotations();
          if (terminals.contains(peek(0))) {
@@ -4390,7 +4389,7 @@ public class DartParser extends CompletionHooksParserBase {
    if (optional(Token.ADD)) {
      if (peek(0) != Token.INTEGER_LITERAL && peek(0) != Token.DOUBLE_LITERAL) {
        reportError(position(), ParserErrorCode.NO_UNARY_PLUS_OPERATOR);
-      } else if (position().getPos() + 1 != peekTokenLocation(0).getBegin().getPos()) {
+      } else if (position() + 1 != peekTokenLocation(0).getBegin()) {
        reportError(position(), ParserErrorCode.NO_SPACE_AFTER_PLUS);
      }
    }
@@ -4401,14 +4400,14 @@ public class DartParser extends CompletionHooksParserBase {
        beginUnaryExpression();
        beginUnaryExpression();
        consume(token);
-        int tokenOffset = ctx.getTokenLocation().getBegin().getPos();
+        int tokenOffset = ctx.getTokenLocation().getBegin();
        DartExpression unary = parseUnaryExpression();
        DartUnaryExpression unary2 = new DartUnaryExpression(Token.SUB, tokenOffset, unary, true);
        return done(new DartUnaryExpression(Token.SUB, tokenOffset, done(unary2), true));
      } else {
        beginUnaryExpression();
        consume(token);
-        int tokenOffset = ctx.getTokenLocation().getBegin().getPos();
+        int tokenOffset = ctx.getTokenLocation().getBegin();
        DartExpression unary = parseUnaryExpression();
        if (token.isCountOperator()) {
          ensureAssignable(unary);
@@ -4611,7 +4610,7 @@ public class DartParser extends CompletionHooksParserBase {
  }
  
  @Override
-  protected void reportError(Position position, ErrorCode errorCode, Object... arguments) {
+  protected void reportError(int position, ErrorCode errorCode, Object... arguments) {
    // TODO(devoncarew): we're not correctly identifying dart:html as a core library
    if (incErrorCount()) {
      super.reportError(position, errorCode, arguments);
@@ -4619,7 +4618,7 @@ public class DartParser extends CompletionHooksParserBase {
  }

  @Override
-  protected void reportErrorAtPosition(Position startPosition, Position endPosition,
+  protected void reportErrorAtPosition(int startPosition, int endPosition,
      ErrorCode errorCode, Object... arguments) {
    if (incErrorCount()) {
      super.reportErrorAtPosition(startPosition, endPosition, errorCode, arguments);
@@ -53,7 +53,7 @@ public class DartParserCommentsHelper {
      }

      @Override
-      protected void recordCommentLocation(int start, int stop, int line, int col) {
+      protected void recordCommentLocation(int start, int stop) {
        int size = commentLocs.size();
        if (size > 0) {
          // the parser may re-scan lookahead tokens
@@ -17,88 +17,34 @@ import java.util.Stack;
 */
 public class DartScanner {

-  /**
-   * Represents a position in a source file, including absolute character position,
-   * line, and column.
-   */
-  public static class Position {
-    private int pos;
-    private int line;
-    private int col;
-
-    public Position(int pos, int line, int col) {
-      this.pos = pos;
-      this.line = line;
-      this.col = col;
-    }
-
-    public Position copy() {
-      return new Position(pos, line, col);
-    }
-
-    public int getPos() {
-      return pos;
-    }
-
-    public int getLine() {
-      return line;
-    }
-
-    public int getCol() {
-      return col;
-    }
-
-    public void advance(boolean isNewline) {
-      ++pos;
-      if (isNewline) {
-        col = 1;
-        ++line;
-      } else {
-        ++col;
-      }
-    }
-
-    /**
-     * @return the {@link Position} which is advanced on the given number of columns, on the same
-     *         line.
-     */
-    public Position getAdvancedColumns(int cols) {
-      return new Position(pos + cols, line, col + cols);
-    }
-
-    @Override
-    public String toString() {
-      return line + "," + col + "@" + pos;
-    }
-  }
-
  /**
   * Represents a span of characters in a source file.
   */
  public static class Location {
    public static final Location NONE = null;
-    private Position begin, end;
+    private int begin;
+    private int end;

-    public Location(Position begin, Position end) {
+    public Location(int begin, int end) {
      this.begin = begin;
      this.end = end;
    }

-    public Location(Position begin) {
+    public Location(int begin) {
      this.begin = this.end = begin;
    }

-    public Position getBegin() {
+    public int getBegin() {
      return begin;
    }

-    public Position getEnd() {
+    public int getEnd() {
      return end;
    }

    @Override
    public String toString() {
-      return begin.toString() + "::" + end.toString();
+      return begin + "::" + end;
    }
  }

@@ -252,8 +198,8 @@ public class DartScanner {
    }

    private int lookahead[] = new int[NUM_LOOKAHEAD];
-    private Position lookaheadPos[] = new Position[NUM_LOOKAHEAD];
-    private Position nextLookaheadPos;
+    private int lookaheadPos[] = new int[NUM_LOOKAHEAD];
+    private int nextLookaheadPos;
    private ArrayList<TokenData> tokens;
    private TokenData lastToken;

@@ -435,7 +381,6 @@ public class DartScanner {
    return c == ' ' || c == '\t';
  }

-  private int commentLineCount;
  private int commentCharCount;
  private int lastCommentStart;
  private int lastCommentStop;
@@ -455,9 +400,9 @@ public class DartScanner {

      // Initialize lookahead positions.
      // TODO Determine if line & column should be relative to 0 or 'start'
-      internalState.nextLookaheadPos = new Position(start, 1, 1);
+      internalState.nextLookaheadPos = start;
      for (int i = 0; i < internalState.lookaheadPos.length; ++i) {
-        internalState.lookaheadPos[i] = new Position(start, 1, 1);
+        internalState.lookaheadPos[i] = start;
      }

      // Fill all the characters in the look-ahead and all the peek
@@ -473,31 +418,11 @@ public class DartScanner {
    }
  }

-  /**
-   * Returns the number of lines of source that were scanned, excluding the number of lines
-   * consumed by comments.
-   */
-  public int getNonCommentLineCount() {
-    return getLineCount() - commentLineCount;
-  }
-
-  /**
-   * Returns the number of lines of source that were scanned.
-   */
-  public int getLineCount() {
-    int lineCount = internalState.nextLookaheadPos.line;
-    if (isEos()) {
-      // At the end of the file the next line has advanced one past the end
-      lineCount -= 1;
-    }
-    return lineCount;
-  }
-
  /**
   * Returns the number of characters of source code that were scanned.
   */
  public int getCharCount() {
-    return internalState.nextLookaheadPos.pos;
+    return internalState.nextLookaheadPos;
  }

  /**
@@ -647,32 +572,28 @@ public class DartScanner {
   * invocation.
   * @param start the character position of the second character in the comment
   * @param stop the character position of the final character in the comment
-   * @param line the line number at <code>start</code>
-   * @param col the column number at <code>start</code>
   */
-  protected void recordCommentLocation(int start, int stop, int line, int col) {
+  protected void recordCommentLocation(int start, int stop) {
  }

  private void advance() {
    for (int i = 0; i < NUM_LOOKAHEAD - 1; ++i) {
      internalState.lookahead[i] = internalState.lookahead[i + 1];
-      internalState.lookaheadPos[i] = internalState.lookaheadPos[i + 1].copy();
+      internalState.lookaheadPos[i] = internalState.lookaheadPos[i + 1];
    }
-    if (internalState.nextLookaheadPos.pos < source.length()) {
-      int ch = source.codePointAt(internalState.nextLookaheadPos.pos);
+    if (internalState.nextLookaheadPos < source.length()) {
+      int ch = source.codePointAt(internalState.nextLookaheadPos);
      internalState.lookahead[NUM_LOOKAHEAD - 1] = ch;
-      internalState.lookaheadPos[NUM_LOOKAHEAD - 1] = internalState.nextLookaheadPos.copy();
-      internalState.nextLookaheadPos.advance(ch == '\n');
+      internalState.lookaheadPos[NUM_LOOKAHEAD - 1] = internalState.nextLookaheadPos;
+      internalState.nextLookaheadPos++;
    } else {
      // Let the last look-ahead position be past the source. This makes
      // the position information for the last token correct.
      internalState.lookahead[NUM_LOOKAHEAD - 1] = -1;
-      internalState.lookaheadPos[NUM_LOOKAHEAD - 1] = new Position(source.length(),
-        internalState.nextLookaheadPos.line, internalState.nextLookaheadPos.col);
+      internalState.lookaheadPos[NUM_LOOKAHEAD - 1] = source.length();

      // Leave the nextLookahead position pointing to the line after the last line
-      internalState.nextLookaheadPos = new Position(source.length(),
-          internalState.nextLookaheadPos.line + 1, 1);
+      internalState.nextLookaheadPos = source.length();
    }
  }

@@ -688,17 +609,16 @@ public class DartScanner {
   * @param endLine the line number of the last line of the comment
   * @param col the column number at <code>start</code>
   */
-  private void commentLocation(int start, int stop, int startLine, int endLine, int col) {
+  private void commentLocation(int start, int stop) {
    if (start <= lastCommentStart && stop <= lastCommentStop) {
      return;
    }

    lastCommentStart = start;
    lastCommentStop = stop;
-    commentLineCount += endLine - startLine + 1;
    commentCharCount += stop - start + 1;

-    recordCommentLocation(start, stop, startLine, col);
+    recordCommentLocation(start, stop);
  }

  private boolean is(int c) {
@@ -715,7 +635,7 @@ public class DartScanner {
  }

  // Get the current source code position.
-  private Position position() {
+  private int position() {
    return internalState.lookaheadPos[0];
  }

@@ -727,7 +647,7 @@ public class DartScanner {
    while (true) {
      internalState.lastToken = new TokenData();
      Token token;
-      Position begin, end;
+      int begin, end;
      do {
        skipWhiteSpace();
        begin = position();
@@ -757,7 +677,7 @@ public class DartScanner {

  private Token scanIdentifier(boolean allowDollars) {
    assert (isIdentifierStart(lookahead(0)));
-    Position begin = position();
+    int begin = position();
    while (true) {
      int nextChar = lookahead(0);
      if (!isIdentifierPart(nextChar) || (!allowDollars && nextChar == '$')) {
@@ -765,11 +685,11 @@ public class DartScanner {
      }
      advance();
    }
-    int size = position().pos - begin.pos;
+    int size = position() - begin;

    // Use a substring of the source string instead of copying all the
    // characters to the token value buffer.
-    String result = source.substring(begin.pos, begin.pos + size);
+    String result = source.substring(begin, begin + size);
    internalState.lastToken.value = result;
    return Token.lookup(result);
  }
@@ -777,7 +697,7 @@ public class DartScanner {
  private Token scanNumber() {
    boolean isDouble = false;
    assert (isDecimalDigit(lookahead(0)) || is('.'));
-    Position begin = position();
+    int begin = position();
    while (isDecimalDigit(lookahead(0)))
      advance();
    if (is('.') && isDecimalDigit(lookahead(1))) {
@@ -801,8 +721,8 @@ public class DartScanner {
      // Number literals must not be followed directly by an identifier.
      return Token.ILLEGAL;
    }
-    int size = position().pos - begin.pos;
-    internalState.lastToken.value = source.substring(begin.pos, begin.pos + size);
+    int size = position() - begin;
+    internalState.lastToken.value = source.substring(begin, begin + size);
    return isDouble ? Token.DOUBLE_LITERAL : Token.INTEGER_LITERAL;
  }

@@ -816,7 +736,7 @@ public class DartScanner {
    advance();
    advance();

-    Position begin = position();
+    int begin = position();
    if (!isHexDigit(lookahead(0))) {
      return Token.ILLEGAL;
    }
@@ -827,7 +747,7 @@ public class DartScanner {
    if (isIdentifierStart(lookahead(0))) {
      return Token.ILLEGAL;
    }
-    internalState.lastToken.value = source.substring(begin.pos, position().pos);
+    internalState.lastToken.value = source.substring(begin, position());
    return Token.HEX_LITERAL;
  }

@@ -1316,18 +1236,16 @@ public class DartScanner {
   */
  private Token scanDirective() {
    assert (is('#'));
-    Position currPos = position();
-    int start = currPos.pos;
-    int line = currPos.line;
-    int col = currPos.col;
+    int currPos = position();
+    int start = currPos;

    // Skip over the #! if it exists and consider it a comment
    if (start == 0) {
      if (lookahead(1) == '!') {
        while (!isEos() && !isLineTerminator(lookahead(0)))
          advance();
-        int stop = internalState.lookaheadPos[0].pos;
-        commentLocation(start, stop, line, internalState.lookaheadPos[0].line, col);
+        int stop = internalState.lookaheadPos[0];
+        commentLocation(start, stop);
        return Token.COMMENT;
      }
    }
@@ -1345,7 +1263,7 @@ public class DartScanner {
      }
      advance();
    }
-    String syntax = source.substring(start, position().pos);
+    String syntax = source.substring(start, position());
    Token token = Token.lookup(syntax);
    return token == Token.IDENTIFIER ? Token.ILLEGAL : token;
  }
@@ -1365,10 +1283,8 @@ public class DartScanner {

  private Token skipMultiLineComment() {
    assert (is('*'));
-    Position currPos = internalState.lookaheadPos[0];
-    int start = currPos.pos - 1;
-    int line = currPos.line;
-    int col = currPos.col;
+    int currPos = internalState.lookaheadPos[0];
+    int start = currPos - 1;
    int commentDepth = 1;
    advance();
    while (!isEos()) {
@@ -1377,8 +1293,8 @@ public class DartScanner {
      if (first == '*' && is('/')) {
        if(--commentDepth == 0) {
          Token result = select(Token.COMMENT);
-          int stop = internalState.lookaheadPos[0].pos;
-          commentLocation(start, stop, line, internalState.lookaheadPos[0].line, col);
+          int stop = internalState.lookaheadPos[0];
+          commentLocation(start, stop);
          return result;
        }
        advance();
@@ -1387,23 +1303,21 @@ public class DartScanner {
        advance();
      }
    }
-    int stop = internalState.lookaheadPos[0].pos;
-    commentLocation(start, stop, line, internalState.lookaheadPos[0].line, col);
+    int stop = internalState.lookaheadPos[0];
+    commentLocation(start, stop);
    // Unterminated multi-line comment.
    return Token.ILLEGAL;
  }

  private Token skipSingleLineComment() {
    assert (is('/'));
-    Position currPos = internalState.lookaheadPos[0];
-    int start = currPos.pos - 1;
-    int line = currPos.line;
-    int col = currPos.col;
+    int currPos = internalState.lookaheadPos[0];
+    int start = currPos - 1;
    advance();
    while (!isEos() && !isLineTerminator(lookahead(0)))
      advance();
-    int stop = internalState.lookaheadPos[0].pos;
-    commentLocation(start, stop, line, internalState.lookaheadPos[0].line, col);
+    int stop = internalState.lookaheadPos[0];
+    commentLocation(start, stop);
    return Token.COMMENT;
  }

@@ -26,7 +26,7 @@ import java.util.Stack;
 class DartScannerParserContext implements ParserContext {
  private DartScanner scanner;
  private Deque<DartScanner.State> stateStack = new ArrayDeque<DartScanner.State>();
-  private Deque<DartScanner.Position> positionStack = new ArrayDeque<DartScanner.Position>();
+  private Deque<Integer> positionStack = new ArrayDeque<Integer>();
  private Source source;
  private DartCompilerListener listener;
  private final CompilerMetrics compilerMetrics;
@@ -50,14 +50,14 @@ class DartScannerParserContext implements ParserContext {
    positionStack.push(getBeginLocation(0));
  }

-  private DartScanner.Position getBeginLocation(int n) {
+  private int getBeginLocation(int n) {
    DartScanner.Location tokenLocation = scanner.peekTokenLocation(n);
-    return tokenLocation != null ? tokenLocation.getBegin() : new DartScanner.Position(0, 1, 1);
+    return tokenLocation != null ? tokenLocation.getBegin() : 0;
  }

-  private DartScanner.Position getEndLocation() {
+  private int getEndLocation() {
    DartScanner.Location tokenLocation = scanner.getTokenLocation();
-    return tokenLocation != null ? tokenLocation.getEnd() : new DartScanner.Position(0, 1, 1);
+    return tokenLocation != null ? tokenLocation.getEnd() : 0;
  }

  @Override
@@ -80,7 +80,7 @@ class DartScannerParserContext implements ParserContext {
    if (result instanceof DartUnit) {
      if (compilerMetrics != null) {
        compilerMetrics.unitParsed(scanner.getCharCount(), scanner.getNonCommentCharCount(),
-            scanner.getLineCount(), scanner.getNonCommentLineCount());
+            0, 0);
      }
    }

@@ -95,11 +95,11 @@ class DartScannerParserContext implements ParserContext {
   * @param result
   * @param startPos
   */
-  private <T> void setSourcePosition(T result, DartScanner.Position startPos) {
+  private <T> void setSourcePosition(T result, int startPos) {
    if (result instanceof HasSourceInfoSetter) {
      HasSourceInfoSetter hasSourceInfoSetter = (HasSourceInfoSetter) result;
-      int start = startPos.getPos();
-      int end = getEndLocation().getPos();
+      int start = startPos;
+      int end = getEndLocation();
      if (start != -1 && end < start) {
        // handle 0-length tokens, including where there is trailing whitespace
        end = start;