8263321: Regression 8% in javadoc-steady in 17-b11

Reviewed-by: prappo, vromero

src/jdk.compiler/share/classes/com/sun/tools/javac/code/Type.java

@@ -468,7 +468,7 @@ public String toString() {
         if (tsym == null || tsym.name == null) {
             sb.append("<none>");
         } else {
-            sb.append(tsym.name);
+            sb.append(tsym.name.toString());
         }
         if (moreInfo && hasTag(TYPEVAR)) {
             sb.append(hashCode());

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/HtmlDocletWriter.java

@@ -1432,7 +1432,7 @@ private boolean inAnAtag() {
 
                 @Override
                 public Boolean visitAttribute(AttributeTree node, Content c) {
-                    StringBuilder sb = new StringBuilder(SPACER).append(node.getName());
+                    StringBuilder sb = new StringBuilder(SPACER).append(node.getName().toString());
                     if (node.getValueKind() == ValueKind.EMPTY) {
                         result.add(sb);
                         return false;
@@ -2050,18 +2050,18 @@ static String getDescription(String prefix, Element elem) {
         }
         StringBuilder sb = new StringBuilder();
         for (Element e: chain) {
-            CharSequence name;
+            String name;
             switch (e.getKind()) {
                 case MODULE:
                 case PACKAGE:
-                    name = ((QualifiedNameable) e).getQualifiedName();
+                    name = ((QualifiedNameable) e).getQualifiedName().toString();
                     if (name.length() == 0) {
                         name = "<unnamed>";
                     }
                     break;
 
                 default:
-                    name = e.getSimpleName();
+                    name = e.getSimpleName().toString();
                     break;
             }
 

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/HtmlIds.java

@@ -216,7 +216,7 @@ HtmlId forMember(TypeElement typeElement, VariableElement member) {
      * @return the 1.4.x style anchor for the executable element
      */
     protected HtmlId forErasure(ExecutableElement executableElement) {
-        final StringBuilder buf = new StringBuilder(executableElement.getSimpleName());
+        final StringBuilder buf = new StringBuilder(executableElement.getSimpleName().toString());
         buf.append("(");
         List<? extends VariableElement> parameters = executableElement.getParameters();
         boolean foundTypeVariable = false;
@@ -237,7 +237,7 @@ public Boolean visitArray(ArrayType t, Void p) {
 
                 @Override
                 public Boolean visitTypeVariable(TypeVariable t, Void p) {
-                    buf.append(utils.asTypeElement(t).getQualifiedName());
+                    buf.append(utils.asTypeElement(t).getQualifiedName().toString());
                     foundTypeVariable = true;
                     return foundTypeVariable;
                 }

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/markup/Entity.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -70,17 +70,19 @@ public int charCount() {
      * @return the string with all of the HTML characters escaped
      */
     static String escapeHtmlChars(CharSequence s) {
-        for (int i = 0; i < s.length(); i++) {
-            char ch = s.charAt(i);
+        // Convert to string as CharSequence implementations can be slow - see JDK-8263321
+        String str = s.toString();
+        for (int i = 0; i < str.length(); i++) {
+            char ch = str.charAt(i);
             switch (ch) {
                 // only start building a new string if we need to
                 case '<': case '>': case '&':
-                    StringBuilder sb = new StringBuilder(s.subSequence(0, i));
-                    escapeHtmlChars(s, i, sb);
+                    StringBuilder sb = new StringBuilder(str.substring(0, i));
+                    escapeHtmlChars(str, i, sb);
                     return sb.toString();
             }
         }
-        return s.toString();
+        return str;
     }
 
     /**
@@ -91,10 +93,10 @@ static String escapeHtmlChars(CharSequence s) {
      * @param sb the string builder
      */
     static void escapeHtmlChars(CharSequence s, StringBuilder sb) {
-        escapeHtmlChars(s, 0, sb);
+        escapeHtmlChars(s.toString(), 0, sb);
     }
 
-    private static void escapeHtmlChars(CharSequence s, int start, StringBuilder sb) {
+    private static void escapeHtmlChars(String s, int start, StringBuilder sb) {
         for (int i = start ; i < s.length(); i++) {
             char ch = s.charAt(i);
             switch (ch) {

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/markup/Text.java

@@ -55,7 +55,7 @@ public static Text of(CharSequence content) {
     }
 
     /**
-     * Constructor to construct FixedStringContent object.
+     * Constructs an immutable text object.
      *
      * @param content content for the object
      */

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/util/CommentHelper.java

@@ -225,7 +225,7 @@ private StringBuilder getText0(DocTree dt) {
         new SimpleDocTreeVisitor<Void, Void>() {
             @Override
             public Void visitAttribute(AttributeTree node, Void p) {
-                sb.append(SPACER).append(node.getName());
+                sb.append(SPACER).append(node.getName().toString());
                 if (node.getValueKind() == ValueKind.EMPTY) {
                     return null;
                 }
@@ -252,7 +252,7 @@ public Void visitAttribute(AttributeTree node, Void p) {
             @Override
             public Void visitEndElement(EndElementTree node, Void p) {
                 sb.append("</")
-                        .append(node.getName())
+                        .append(node.getName().toString())
                         .append(">");
                 return null;
             }
@@ -307,7 +307,7 @@ public Void visitSerial(SerialTree node, Void p) {
             @Override
             public Void visitStartElement(StartElementTree node, Void p) {
                 sb.append("<");
-                sb.append(node.getName());
+                sb.append(node.getName().toString());
                 node.getAttributes().forEach(dt -> dt.accept(this, null));
                 sb.append(node.isSelfClosing() ? "/>" : ">");
                 return null;

src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/toolkit/util/Utils.java

@@ -2158,7 +2158,7 @@ public String visitModule(ModuleElement e, Void p) {
 
                 @Override
                 public String visitType(TypeElement e, Void p) {
-                    StringBuilder sb = new StringBuilder(e.getSimpleName());
+                    StringBuilder sb = new StringBuilder(e.getSimpleName().toString());
                     Element enclosed = e.getEnclosingElement();
                     while (enclosed != null
                             && (enclosed.getKind().isClass() || enclosed.getKind().isInterface())) {