MinGW: Use a response file for long include paths

Change-Id: I55ce73ad08473bca27c7ab5730f633fb77c9b8cd
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

3 files changed, 28 insertions, 7 deletions

diff --git a/qmake/generators/makefile.cpp b/qmake/generators/makefile.cpp
index f6f4edef9d..dfe9a1c0b9 100644
--- a/qmake/generators/makefile.cpp
+++ b/qmake/generators/makefile.cpp
@@ -3456,7 +3456,10 @@ ProKey MakefileGenerator::fullTargetVariable() const
     return "TARGET";
 }
 
-QString MakefileGenerator::createResponseFile(const QString &baseName, const ProStringList &objList)
+QString MakefileGenerator::createResponseFile(
+        const QString &baseName,
+        const ProStringList &objList,
+        const QString &prefix)
 {
     QString fileName = baseName + '.' + fileVar("QMAKE_ORIG_TARGET");
     if (!var("BUILD_NAME").isEmpty())
@@ -3479,7 +3482,7 @@ QString MakefileGenerator::createResponseFile(const QString &baseName, const Pro
             .replace(QLatin1Char('\t'), QLatin1String("\\\t"))
             .replace(QLatin1Char('"'), QLatin1String("\\\""))
             .replace(QLatin1Char('\''), QLatin1String("\\'"));
-        t << path << Qt::endl;
+        t << prefix << path << Qt::endl;
     }
     t.flush();
     file.close();
diff --git a/qmake/generators/makefile.h b/qmake/generators/makefile.h
index 2fd7df1e6a..6bd2d649fb 100644
--- a/qmake/generators/makefile.h
+++ b/qmake/generators/makefile.h
@@ -36,6 +36,7 @@
 #include <qlist.h>
 #include <qhash.h>
 #include <qfileinfo.h>
+#include <functional>
 
 QT_BEGIN_NAMESPACE
 
@@ -264,7 +265,9 @@ protected:
                                     QStringView fixedBase, int slashOff);
     bool processPrlFileCore(QString &origFile, QStringView origName,
                             const QString &fixedFile);
-    QString createResponseFile(const QString &baseName, const ProStringList &objList);
+    QString createResponseFile(const QString &baseName,
+                               const ProStringList &objList,
+                               const QString &prefix = QString());
 
 public:
     QMakeProject *projectFile() const;
diff --git a/qmake/generators/win32/mingw_make.cpp b/qmake/generators/win32/mingw_make.cpp
index eb100764ae..823b799eb2 100644
--- a/qmake/generators/win32/mingw_make.cpp
+++ b/qmake/generators/win32/mingw_make.cpp
@@ -201,11 +201,26 @@ void MingwMakefileGenerator::writeIncPart(QTextStream &t)
     t << "INCPATH       = ";
 
     const ProStringList &incs = project->values("INCLUDEPATH");
-    for (ProStringList::ConstIterator incit = incs.begin(); incit != incs.end(); ++incit) {
-        QString inc = (*incit).toQString();
+    QFile responseFile;
+    QTextStream responseStream;
+    QChar sep(' ');
+    int totalLength = std::accumulate(incs.constBegin(), incs.constEnd(), 0,
+                                      [](int total, const ProString &inc) {
+        return total + inc.size() + 2;
+    });
+    if (totalLength > project->intValue("QMAKE_RESPONSEFILE_THRESHOLD", 8000)) {
+        const QString fileName = createResponseFile("incpath", incs, "-I");
+        if (!fileName.isEmpty()) {
+            t << '@' + fileName;
+            t << Qt::endl;
+            return;
+        }
+    }
+    for (const ProString &incit: qAsConst(incs)) {
+        QString inc = incit.toQString();
         inc.replace(QRegularExpression("\\\\$"), "");
-
-        t << "-I" << escapeFilePath(inc) << ' ';
+        inc.replace('\\', '/');
+        t << "-I" << escapeFilePath(inc) << sep;
     }
     t << Qt::endl;
 }