diff --git a/src/tools/qdoc/htmlgenerator.cpp b/src/tools/qdoc/htmlgenerator.cpp
index f9fc534c702..fc880b404fa 100644
--- a/src/tools/qdoc/htmlgenerator.cpp
+++ b/src/tools/qdoc/htmlgenerator.cpp
@@ -49,6 +49,7 @@
 #include <qiterator.h>
 #include <qtextcodec.h>
 #include <quuid.h>
+#include <qmap.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -71,11 +72,11 @@ static void addLink(const QString &linkTarget,
                     QString *res)
 {
     if (!linkTarget.isEmpty()) {
-        *res += "<a href=\"";
+        *res += QLatin1String("<a href=\"");
         *res += linkTarget;
-        *res += "\">";
+        *res += QLatin1String("\">");
         *res += nestedStuff;
-        *res += "</a>";
+        *res += QLatin1String("</a>");
     }
     else {
         *res += nestedStuff;
@@ -139,8 +140,8 @@ void HtmlGenerator::initializeGenerator(const Config &config)
      */
     int i = 0;
     while (defaults[i].key) {
-        formattingLeftMap().insert(defaults[i].key, defaults[i].left);
-        formattingRightMap().insert(defaults[i].key, defaults[i].right);
+        formattingLeftMap().insert(QLatin1String(defaults[i].key), QLatin1String(defaults[i].left));
+        formattingRightMap().insert(QLatin1String(defaults[i].key), QLatin1String(defaults[i].right));
         i++;
     }
 
@@ -180,7 +181,7 @@ void HtmlGenerator::initializeGenerator(const Config &config)
 
     projectDescription = config.getString(CONFIG_DESCRIPTION);
     if (projectDescription.isEmpty() && !project.isEmpty())
-        projectDescription = project + " Reference Documentation";
+        projectDescription = project + QLatin1String(" Reference Documentation");
 
     projectUrl = config.getString(CONFIG_URL);
     tagFile_ = config.getString(CONFIG_TAGFILE);
@@ -236,8 +237,8 @@ void HtmlGenerator::initializeGenerator(const Config &config)
     headerStyles = config.getString(HtmlGenerator::format() + Config::dot + CONFIG_HEADERSTYLES);
 
     QString prefix = CONFIG_QHP + Config::dot + project + Config::dot;
-    manifestDir = "qthelp://" + config.getString(prefix + "namespace");
-    manifestDir += QLatin1Char('/') + config.getString(prefix + "virtualFolder") + QLatin1Char('/');
+    manifestDir = QLatin1String("qthelp://") + config.getString(prefix + QLatin1String("namespace"));
+    manifestDir += QLatin1Char('/') + config.getString(prefix + QLatin1String("virtualFolder")) + QLatin1Char('/');
     readManifestMetaContent(config);
     examplesPath = config.getString(CONFIG_EXAMPLESINSTALLPATH);
     if (!examplesPath.isEmpty())
@@ -285,7 +286,7 @@ void HtmlGenerator::generateKeywordAnchors(const Node* node)
     if (!node->doc().isEmpty()) {
         const QList<Atom*>& keywords = node->doc().keywords();
         foreach (Atom* a, keywords) {
-            out() << "<a name=\"" << Doc::canonicalTitle(a->string()) << "\"></a>";
+            out() << QLatin1String("<a name=\"") << Doc::canonicalTitle(a->string()) << QLatin1String("\"></a>");
         }
     }
 }
@@ -539,9 +540,9 @@ int HtmlGenerator::generateAtom(const Atom *atom, const Node *relative, CodeMark
             else
                 out() << "variable";
             QStringList words = str.split(QLatin1Char(' '));
-            if (!(words.first() == "contains" || words.first() == "specifies"
-                  || words.first() == "describes" || words.first() == "defines"
-                  || words.first() == "holds" || words.first() == "determines"))
+            if (!(words.first() == QLatin1String("contains") || words.first() == QLatin1String("specifies")
+                  || words.first() == QLatin1String("describes") || words.first() == QLatin1String("defines")
+                  || words.first() == QLatin1String("holds") || words.first() == QLatin1String("determines")))
                 out() << " holds ";
             else
                 out() << ' ';
@@ -666,20 +667,20 @@ int HtmlGenerator::generateAtom(const Atom *atom, const Node *relative, CodeMark
         }
         break;
     case Atom::GeneratedList:
-        if (atom->string() == "annotatedclasses") {
+        if (atom->string() == QLatin1String("annotatedclasses")) {
             generateAnnotatedList(relative, marker, qdb_->getCppClasses());
         }
-        else if (atom->string() == "classes") {
+        else if (atom->string() == QLatin1String("classes")) {
             generateCompactList(Generic, relative, qdb_->getCppClasses(), true, QStringLiteral(""));
         }
         else if (atom->string().contains("classes ")) {
             QString rootName = atom->string().mid(atom->string().indexOf("classes") + 7).trimmed();
             generateCompactList(Generic, relative, qdb_->getCppClasses(), true, rootName);
         }
-        else if (atom->string() == "qmlbasictypes") {
+        else if (atom->string() == QLatin1String("qmlbasictypes")) {
             generateCompactList(Generic, relative, qdb_->getQmlBasicTypes(), true, QStringLiteral(""));
         }
-        else if (atom->string() == "qmltypes") {
+        else if (atom->string() == QLatin1String("qmltypes")) {
             generateCompactList(Generic, relative, qdb_->getQmlTypes(), true, QStringLiteral(""));
         }
         else if (atom->string().contains("classesbymodule")) {
@@ -694,40 +695,40 @@ int HtmlGenerator::generateAtom(const Atom *atom, const Node *relative, CodeMark
                 }
             }
         }
-        else if (atom->string() == "classhierarchy") {
+        else if (atom->string() == QLatin1String("classhierarchy")) {
             generateClassHierarchy(relative, qdb_->getCppClasses());
         }
-        else if (atom->string() == "obsoleteclasses") {
+        else if (atom->string() == QLatin1String("obsoleteclasses")) {
             generateCompactList(Generic, relative, qdb_->getObsoleteClasses(), false, QStringLiteral("Q"));
         }
-        else if (atom->string() == "obsoleteqmltypes") {
+        else if (atom->string() == QLatin1String("obsoleteqmltypes")) {
             generateCompactList(Generic, relative, qdb_->getObsoleteQmlTypes(), false, QStringLiteral(""));
         }
-        else if (atom->string() == "obsoletecppmembers") {
+        else if (atom->string() == QLatin1String("obsoletecppmembers")) {
             generateCompactList(Obsolete, relative, qdb_->getClassesWithObsoleteMembers(), false, QStringLiteral("Q"));
         }
-        else if (atom->string() == "obsoleteqmlmembers") {
+        else if (atom->string() == QLatin1String("obsoleteqmlmembers")) {
             generateCompactList(Obsolete, relative, qdb_->getQmlTypesWithObsoleteMembers(), false, QStringLiteral(""));
         }
-        else if (atom->string() == "functionindex") {
+        else if (atom->string() == QLatin1String("functionindex")) {
             generateFunctionIndex(relative);
         }
-        else if (atom->string() == "legalese") {
+        else if (atom->string() == QLatin1String("legalese")) {
             generateLegaleseList(relative, marker);
         }
-        else if (atom->string() == "overviews") {
+        else if (atom->string() == QLatin1String("overviews")) {
             generateList(relative, marker, "overviews");
         }
-        else if (atom->string() == "cpp-modules") {
+        else if (atom->string() == QLatin1String("cpp-modules")) {
             generateList(relative, marker, "cpp-modules");
         }
-        else if (atom->string() == "qml-modules") {
+        else if (atom->string() == QLatin1String("qml-modules")) {
             generateList(relative, marker, "qml-modules");
         }
-        else if (atom->string() == "namespaces") {
+        else if (atom->string() == QLatin1String("namespaces")) {
             generateAnnotatedList(relative, marker, qdb_->getNamespaces());
         }
-        else if (atom->string() == "related") {
+        else if (atom->string() == QLatin1String("related")) {
             generateList(relative, marker, "related");
         }
 #if 0
@@ -735,7 +736,7 @@ int HtmlGenerator::generateAtom(const Atom *atom, const Node *relative, CodeMark
           This is not used in Qt5, as of 10/02/2014
           Remove permanently if it is not missed.
          */
-        else if (atom->string() == "relatedinline") {
+        else if (atom->string() == QLatin1String("relatedinline")) {
             const DocumentNode *dn = static_cast<const DocumentNode *>(relative);
             if (dn && !dn->members().isEmpty()) {
                 // Reverse the list into the original scan order.
@@ -1210,13 +1211,13 @@ int HtmlGenerator::generateAtom(const Atom *atom, const Node *relative, CodeMark
                 p2 = atom->string(1);
         }
         if (!p1.isEmpty()) {
-            if (p1 == "borderless")
+            if (p1 == QLatin1String("borderless"))
                 attr = p1;
             else if (p1.contains("%"))
                 width = p1;
         }
         if (!p2.isEmpty()) {
-            if (p2 == "borderless")
+            if (p2 == QLatin1String("borderless"))
                 attr = p2;
             else if (p2.contains("%"))
                 width = p2;
@@ -3158,13 +3159,13 @@ void HtmlGenerator::generateList(const Node* relative, CodeMarker* marker, const
 {
     CNMap cnm;
     Node::Genus genus = Node::DontCare;
-    if (selector == "overviews")
+    if (selector == QLatin1String("overviews"))
         genus = Node::DOC;
-    else if (selector == "cpp-modules")
+    else if (selector == QLatin1String("cpp-modules"))
         genus = Node::CPP;
-    else if (selector == "qml-modules")
+    else if (selector == QLatin1String("qml-modules"))
         genus = Node::QML;
-    else if (selector == "js-modules")
+    else if (selector == QLatin1String("js-modules"))
         genus = Node::JS;
     if (genus != Node::DontCare) {
         NodeList nl;
@@ -3409,6 +3410,7 @@ QString HtmlGenerator::highlightedCode(const QString& markedCode,
 {
     QString src = markedCode;
     QString html;
+    html.reserve(src.size());
     QStringRef arg;
     QStringRef par1;
 
@@ -3421,62 +3423,30 @@ QString HtmlGenerator::highlightedCode(const QString& markedCode,
     static const QString linkTag("link");
 
     // replace all <@link> tags: "(<@link node=\"([^\"]+)\">).*(</@link>)"
+    // replace all <@func> tags: "(<@func target=\"([^\"]*)\">)(.*)(</@func>)"
+    // replace all "(<@(type|headerfile)(?: +[^>]*)?>)(.*)(</@\\2>)" tags
     bool done = false;
     for (int i = 0, srcSize = src.size(); i < srcSize;) {
         if (src.at(i) == charLangle && src.at(i + 1) == charAt) {
             if (alignNames && !done) {
-                html += "</td><td class=\"memItemRight bottomAlign\">";
+                html += QLatin1String("</td><td class=\"memItemRight bottomAlign\">");
                 done = true;
             }
             i += 2;
             if (parseArg(src, linkTag, &i, srcSize, &arg, &par1)) {
-                html += "<b>";
+                html += QLatin1String("<b>");
                 const Node* n = CodeMarker::nodeForString(par1.toString());
                 QString link = linkForNode(n, relative);
                 addLink(link, arg, &html);
-                html += "</b>";
+                html += QLatin1String("</b>");
             }
-            else {
-                html += charLangle;
-                html += charAt;
-            }
-        }
-        else {
-            html += src.at(i++);
-        }
-    }
-
-    // replace all <@func> tags: "(<@func target=\"([^\"]*)\">)(.*)(</@func>)"
-    src = html;
-    html = QString();
-    for (int i = 0, srcSize = src.size(); i < srcSize;) {
-        if (src.at(i) == charLangle && src.at(i + 1) == charAt) {
-            i += 2;
-            if (parseArg(src, funcTag, &i, srcSize, &arg, &par1)) {
+            else if (parseArg(src, funcTag, &i, srcSize, &arg, &par1)) {
                 const Node* n = qdb_->findFunctionNode(par1.toString(), relative, Node::DontCare);
                 QString link = linkForNode(n, relative);
                 addLink(link, arg, &html);
                 par1 = QStringRef();
             }
-            else {
-                html += charLangle;
-                html += charAt;
-            }
-        }
-        else {
-            html += src.at(i++);
-        }
-    }
-
-    // replace all "(<@(type|headerfile)(?: +[^>]*)?>)(.*)(</@\\2>)" tags
-    src = html;
-    html = QString();
-
-    for (int i=0, srcSize=src.size(); i<srcSize;) {
-        if (src.at(i) == charLangle && src.at(i+1) == charAt) {
-            i += 2;
-            bool handled = false;
-            if (parseArg(src, typeTag, &i, srcSize, &arg, &par1)) {
+            else if (parseArg(src, typeTag, &i, srcSize, &arg, &par1)) {
                 par1 = QStringRef();
                 const Node* n = qdb_->findTypeNode(arg.toString(), relative);
                 html += QLatin1String("<span class=\"type\">");
@@ -3489,7 +3459,6 @@ QString HtmlGenerator::highlightedCode(const QString& markedCode,
                 else
                     addLink(linkForNode(n,relative), arg, &html);
                 html += QLatin1String("</span>");
-                handled = true;
             }
             else if (parseArg(src, headerTag, &i, srcSize, &arg, &par1)) {
                 par1 = QStringRef();
@@ -3502,9 +3471,8 @@ QString HtmlGenerator::highlightedCode(const QString& markedCode,
                     else
                         html += arg;
                 }
-                handled = true;
             }
-            if (!handled) {
+            else {
                 html += charLangle;
                 html += charAt;
             }
@@ -3527,60 +3495,68 @@ QString HtmlGenerator::highlightedCode(const QString& markedCode,
     // "</@(?:comment|preprocessor|string|char|number|op|type|name|keyword)>" -> "</span>"
     src = html;
     html = QString();
-    static const QString spanTags[] = {
-        "<@comment>",       "<span class=\"comment\">",
-        "<@preprocessor>",  "<span class=\"preprocessor\">",
-        "<@string>",        "<span class=\"string\">",
-        "<@char>",          "<span class=\"char\">",
-        "<@number>",        "<span class=\"number\">",
-        "<@op>",            "<span class=\"operator\">",
-        "<@type>",          "<span class=\"type\">",
-        "<@name>",          "<span class=\"name\">",
-        "<@keyword>",       "<span class=\"keyword\">",
-        "</@comment>",      "</span>",
-        "</@preprocessor>", "</span>",
-        "</@string>",       "</span>",
-        "</@char>",         "</span>",
-        "</@number>",       "</span>",
-        "</@op>",           "</span>",
-        "</@type>",         "</span>",
-        "</@name>",         "</span>",
-        "</@keyword>",      "</span>",
+    html.reserve(src.size());
+    static const QLatin1String spanTags[] = {
+        QLatin1String("comment>"),       QLatin1String("<span class=\"comment\">"),
+        QLatin1String("preprocessor>"),  QLatin1String("<span class=\"preprocessor\">"),
+        QLatin1String("string>"),        QLatin1String("<span class=\"string\">"),
+        QLatin1String("char>"),          QLatin1String("<span class=\"char\">"),
+        QLatin1String("number>"),        QLatin1String("<span class=\"number\">"),
+        QLatin1String("op>"),            QLatin1String("<span class=\"operator\">"),
+        QLatin1String("type>"),          QLatin1String("<span class=\"type\">"),
+        QLatin1String("name>"),          QLatin1String("<span class=\"name\">"),
+        QLatin1String("keyword>"),       QLatin1String("<span class=\"keyword\">")
     };
+    int nTags = 9;
     // Update the upper bound of k in the following code to match the length
     // of the above array.
     for (int i = 0, n = src.size(); i < n;) {
-        if (src.at(i) == charLangle) {
-            bool handled = false;
-            for (int k = 0; k != 18; ++k) {
-                const QString & tag = spanTags[2 * k];
-                if (i + tag.length() <= src.length() &&
-                    tag == QStringRef(&src, i, tag.length())) {
-                    html += spanTags[2 * k + 1];
-                    i += tag.length();
-                    handled = true;
-                    break;
+        if (src.at(i) == QLatin1Char('<')) {
+            if (src.at(i + 1) == QLatin1Char('@')) {
+                i += 2;
+                bool handled = false;
+                for (int k = 0; k != nTags; ++k) {
+                    const QLatin1String& tag = spanTags[2 * k];
+                    if (i + tag.size() <= src.length() &&
+                        tag == QStringRef(&src, i, tag.size())) {
+                        html += spanTags[2 * k + 1];
+                        i += tag.size();
+                        handled = true;
+                        break;
+                    }
                 }
-            }
-            if (!handled) {
-                ++i;
-                if (src.at(i) == charAt ||
-                        (src.at(i) == QLatin1Char('/') && src.at(i + 1) == charAt)) {
+                if (!handled) {
                     // drop 'our' unknown tags (the ones still containing '@')
                     while (i < n && src.at(i) != QLatin1Char('>'))
                         ++i;
                     ++i;
                 }
-                else {
-                    // retain all others
-                    html += charLangle;
+                continue;
+            }
+            else if (src.at(i + 1) == QLatin1Char('/') && src.at(i + 2) == QLatin1Char('@')) {
+                i += 3;
+                bool handled = false;
+                for (int k = 0; k != nTags; ++k) {
+                    const QLatin1String& tag = spanTags[2 * k];
+                    if (i + tag.size() <= src.length() &&
+                        tag == QStringRef(&src, i, tag.size())) {
+                        html += QLatin1String("</span>");
+                        i += tag.size();
+                        handled = true;
+                        break;
+                    }
                 }
+                if (!handled) {
+                    // drop 'our' unknown tags (the ones still containing '@')
+                    while (i < n && src.at(i) != QLatin1Char('>'))
+                        ++i;
+                    ++i;
+                }
+                continue;
             }
         }
-        else {
-            html += src.at(i);
-            ++i;
-        }
+        html += src.at(i);
+        ++i;
     }
     return html;
 }
@@ -3655,7 +3631,7 @@ QString HtmlGenerator::protect(const QString &string, const QString &outputEncod
             APPEND("&gt;");
         } else if (ch == QLatin1Char('"')) {
             APPEND("&quot;");
-        } else if ((outputEncoding == "ISO-8859-1" && ch.unicode() > 0x007F)
+        } else if ((outputEncoding == QLatin1String("ISO-8859-1") && ch.unicode() > 0x007F)
                    || (ch == QLatin1Char('*') && i + 1 < n && string.at(i) == QLatin1Char('/'))
                    || (ch == QLatin1Char('.') && i > 2 && string.at(i - 2) == QLatin1Char('.'))) {
             // we escape '*/' and the last dot in 'e.g.' and 'i.e.' for the Javadoc generator
@@ -3684,10 +3660,10 @@ QString HtmlGenerator::fileBase(const Node *node) const
     if (!node->isAggregate()) {
         switch (node->status()) {
         case Node::Compat:
-            result += "-compat";
+            result += QLatin1String("-compat");
             break;
         case Node::Obsolete:
-            result += "-obsolete";
+            result += QLatin1String("-obsolete");
             break;
         default:
             ;
@@ -4423,7 +4399,7 @@ void HtmlGenerator::generateManifestFile(const QString &manifest, const QString
     QString fileName = manifest +"-manifest.xml";
     QFile file(outputDir() + QLatin1Char('/') + fileName);
     bool demos = false;
-    if (manifest == "demos")
+    if (manifest == QLatin1String("demos"))
         demos = true;
 
     bool proceed = false;
diff --git a/src/tools/qdoc/htmlgenerator.h b/src/tools/qdoc/htmlgenerator.h
index 6a550c2b39b..d46fc9ebee5 100644
--- a/src/tools/qdoc/htmlgenerator.h
+++ b/src/tools/qdoc/htmlgenerator.h
@@ -38,7 +38,7 @@
 #ifndef HTMLGENERATOR_H
 #define HTMLGENERATOR_H
 
-#include <qmap.h>
+#include <qhash.h>
 #include <qregexp.h>
 #include <qxmlstream.h>
 #include "codemarker.h"
@@ -187,7 +187,6 @@ private:
     void generateQmlInstantiates(QmlTypeNode* qcn, CodeMarker* marker);
     void generateInstantiatedBy(ClassNode* cn, CodeMarker* marker);
 
-    void generateRequisitesTable(const QStringList& requisitesOrder, QMap<QString, Text>& requisites);
     void generateSection(const NodeList& nl,
                          const Node *relative,
                          CodeMarker *marker,
@@ -232,7 +231,7 @@ private:
     void writeDitaRefs(const DitaRefList& ditarefs);
     QXmlStreamWriter& xmlWriter();
 
-    QMap<QString, QString> refMap;
+    QHash<QString, QString> refMap;
     int codeIndent;
     HelpProjectWriter *helpProjectWriter;
     bool inObsoleteLink;
diff --git a/src/tools/qdoc/quoter.cpp b/src/tools/qdoc/quoter.cpp
index d8a4df33f3a..25cf27f7310 100644
--- a/src/tools/qdoc/quoter.cpp
+++ b/src/tools/qdoc/quoter.cpp
@@ -39,6 +39,8 @@
 
 QT_BEGIN_NAMESPACE
 
+QHash<QString,QString> Quoter::commentHash;
+
 static void replaceMultipleNewlines(QString &s)
 {
     const int n = s.size();
@@ -120,14 +122,16 @@ Quoter::Quoter()
         * .html, .qrc, .ui, .xq, .xml .dita files:
           <!-- [<id>] -->
     */
-    commentHash["pro"] = "#!";
-    commentHash["py"] = "#!";
-    commentHash["html"] = "<!--";
-    commentHash["qrc"] = "<!--";
-    commentHash["ui"] = "<!--";
-    commentHash["xml"] = "<!--";
-    commentHash["dita"] = "<!--";
-    commentHash["xq"] = "<!--";
+    if (!commentHash.size()) {
+        commentHash["pro"] = "#!";
+        commentHash["py"] = "#!";
+        commentHash["html"] = "<!--";
+        commentHash["qrc"] = "<!--";
+        commentHash["ui"] = "<!--";
+        commentHash["xml"] = "<!--";
+        commentHash["dita"] = "<!--";
+        commentHash["xq"] = "<!--";
+    }
 }
 
 void Quoter::reset()
diff --git a/src/tools/qdoc/quoter.h b/src/tools/qdoc/quoter.h
index 2c3fa3980d3..7877eda696e 100644
--- a/src/tools/qdoc/quoter.h
+++ b/src/tools/qdoc/quoter.h
@@ -78,7 +78,7 @@ private:
     QStringList plainLines;
     QStringList markedLines;
     Location codeLocation;
-    QHash<QString,QString> commentHash;
+    static QHash<QString,QString> commentHash;
 };
 
 QT_END_NAMESPACE