Keep the original encoded text around while preprocessing.

src/libs/cplusplus/CppDocument.cpp

@@ -356,7 +356,7 @@ void Snapshot::insert(Document::Ptr doc)
         insert(doc->fileName(), doc);
 }
 
-QByteArray Snapshot::preprocessedCode(const QByteArray &source, const QString &fileName) const
+QByteArray Snapshot::preprocessedCode(const QString &source, const QString &fileName) const
 {
     FastPreprocessor pp(*this);
     return pp.run(fileName, source);

src/libs/cplusplus/CppDocument.h

@@ -272,7 +272,7 @@ public:
     Snapshot();
     ~Snapshot();
 
-    QByteArray preprocessedCode(const QByteArray &source,
+    QByteArray preprocessedCode(const QString &source,
                                 const QString &fileName) const;
 
     Document::Ptr documentFromSource(const QByteArray &preprocessedCode,

src/libs/cplusplus/FastPreprocessor.cpp

@@ -36,7 +36,7 @@ FastPreprocessor::FastPreprocessor(const Snapshot &snapshot)
       _preproc(this, &_env)
 { }
 
-QByteArray FastPreprocessor::run(QString fileName, const QByteArray &source)
+QByteArray FastPreprocessor::run(QString fileName, const QString &source)
 {
     const QByteArray preprocessed = _preproc(fileName, source);
     return preprocessed;

src/libs/cplusplus/FastPreprocessor.h

@@ -51,7 +51,7 @@ class CPLUSPLUS_EXPORT FastPreprocessor: public Client
 public:
     FastPreprocessor(const Snapshot &snapshot);
 
-    QByteArray run(QString fileName, const QByteArray &source);
+    QByteArray run(QString fileName, const QString &source);
 
     // CPlusPlus::Client
     virtual void sourceNeeded(QString &fileName, IncludeType, unsigned)

src/libs/cplusplus/pp-engine.cpp

@@ -564,11 +564,21 @@ void Preprocessor::popState()
     _savedStates.removeLast();
 }
 
-QByteArray Preprocessor::operator()(const QString &filename,
+QByteArray Preprocessor::operator()(const QString &fileName, const QString &source)
+{
+    const QString previousOriginalSource = _originalSource;
+    _originalSource = source;
+    const QByteArray bytes = source.toLatin1();
+    const QByteArray preprocessedCode = operator()(fileName, bytes);
+    _originalSource = previousOriginalSource;
+    return preprocessedCode;
+}
+
+QByteArray Preprocessor::operator()(const QString &fileName,
                                     const QByteArray &source)
 {
     QByteArray preprocessed;
-    preprocess(filename, source, &preprocessed);
+    preprocess(fileName, source, &preprocessed);
     return preprocessed;
 }
 
@@ -1098,7 +1108,7 @@ void Preprocessor::processInclude(bool, TokenIterator firstToken,
         const char *beginOfPath = endOfToken(*start);
         const char *endOfPath = startOfToken(*tk);
 
-        QString fn = QString::fromUtf8(beginOfPath, endOfPath - beginOfPath);
+        QString fn = string(beginOfPath, endOfPath - beginOfPath);
         client->sourceNeeded(fn, Client::IncludeGlobal, firstToken->lineno);
 
     } else if (tk->is(T_ANGLE_STRING_LITERAL) || tk->is(T_STRING_LITERAL)) {
@@ -1111,7 +1121,7 @@ void Preprocessor::processInclude(bool, TokenIterator firstToken,
         if (beginOfPath + 1 != endOfPath && ((quote == '"' && endOfPath[-1] == '"') ||
                                               (quote == '<' && endOfPath[-1] == '>'))) {
 
-            QString fn = QString::fromUtf8(beginOfPath + 1, spell.length() - 2);
+            QString fn = string(beginOfPath + 1, spell.length() - 2);
             client->sourceNeeded(fn, Client::IncludeLocal, firstToken->lineno);
         }
     }
@@ -1422,3 +1432,12 @@ bool Preprocessor::isQtReservedWord(const QByteArray &macroId) const
         return true;
     return false;
 }
+
+QString Preprocessor::string(const char *first, int length) const
+{
+    if (_originalSource.isEmpty())
+        return QString::fromUtf8(first, length);
+
+    const int position = first - _source.constData();
+    return _originalSource.mid(position, length);
+}

src/libs/cplusplus/pp-engine.h

@@ -50,25 +50,23 @@
 #define CPLUSPLUS_PP_ENGINE_H
 
 #include "PreprocessorClient.h"
+#include "pp-macro-expander.h"
 
 #include <Token.h>
 #include <QVector>
 
-namespace CPlusPlus {
-    class Token;
-}
-
 namespace CPlusPlus {
 
 struct Value;
+class Environment;
 
 class CPLUSPLUS_EXPORT Preprocessor
 {
 public:
     Preprocessor(Client *client, Environment *env);
 
-    QByteArray operator()(const QString &filename,
-                          const QByteArray &source);
+    QByteArray operator()(const QString &filename, const QString &source);
+    QByteArray operator()(const QString &filename, const QByteArray &source);
 
     void preprocess(const QString &filename,
                     const QByteArray &source,
@@ -169,6 +167,8 @@ private:
     void out(char ch);
     void out(const char *s);
 
+    QString string(const char *first, int len) const;
+
 private:
     Client *client;
     Environment *env;
@@ -186,6 +186,8 @@ private:
 
     QByteArray *_result;
     bool _markGeneratedTokens;
+
+    QString _originalSource;
 };
 
 } // namespace CPlusPlus