Debugging: Enable Windows debugging for clang tools

On Windows the debugging of clang tools is not working due to the
nature of how processes are started.

This makes it possible to use DebugViewer or DebugViewPP

Change-Id: I2c1e4bb7a8fafd6f07570e5d2ba4df5b44e9d44d
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

3 files changed, 9 insertions, 19 deletions

diff --git a/src/tools/clangbackend/clangbackendmain.cpp b/src/tools/clangbackend/clangbackendmain.cpp
index 1e95db3ef3..76aff06d3b 100644
--- a/src/tools/clangbackend/clangbackendmain.cpp
+++ b/src/tools/clangbackend/clangbackendmain.cpp
@@ -57,25 +57,11 @@ QString processArguments(QCoreApplication &application)
 }
 
 #ifdef Q_OS_WIN
-struct MessageHandler {
-    MessageHandler(QtMessageHandler handler)
-    {
-        defaultHandler = qInstallMessageHandler(handler);
-    }
-
-    ~MessageHandler()
-    {
-        qInstallMessageHandler(defaultHandler);
-    }
-
-    static QtMessageHandler defaultHandler;
-};
-
-QtMessageHandler MessageHandler::defaultHandler = nullptr;
-
-static void messageOutput(QtMsgType type, const QMessageLogContext &context, const QString &msg)
+extern "C" void OutputDebugStringW(const wchar_t* msg);
+static void messageOutput(QtMsgType type, const QMessageLogContext &/*context*/,
+                          const QString &msg)
 {
-    MessageHandler::defaultHandler(type, context, msg);
+    OutputDebugStringW(msg.toStdWString().c_str());
     std::wcout << msg.toStdWString() << std::endl;
     if (type == QtFatalMsg)
         abort();
@@ -85,7 +71,7 @@ static void messageOutput(QtMsgType type, const QMessageLogContext &context, con
 int main(int argc, char *argv[])
 {
 #ifdef Q_OS_WIN
-    MessageHandler messageHandler(&messageOutput);
+     qInstallMessageHandler(&messageOutput);
 #endif
     QCoreApplication::setOrganizationName(QStringLiteral("QtProject"));
     QCoreApplication::setOrganizationDomain(QStringLiteral("qt-project.org"));
diff --git a/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp b/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp
index 7a871bb033..a4b5ec3b52 100644
--- a/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp
+++ b/src/tools/clangpchmanagerbackend/clangpchmanagerbackendmain.cpp
@@ -247,8 +247,10 @@ struct Data // because we have a cycle dependency
 };
 
 #ifdef Q_OS_WIN
+extern "C" void OutputDebugStringW(const wchar_t* msg);
 static void messageOutput(QtMsgType type, const QMessageLogContext &, const QString &msg)
 {
+    OutputDebugStringW(msg.toStdWString().c_str());
     std::wcout << msg.toStdWString() << std::endl;
     if (type == QtFatalMsg)
         abort();
diff --git a/src/tools/clangrefactoringbackend/clangrefactoringbackendmain.cpp b/src/tools/clangrefactoringbackend/clangrefactoringbackendmain.cpp
index aaef21b608..bca4551b2f 100644
--- a/src/tools/clangrefactoringbackend/clangrefactoringbackendmain.cpp
+++ b/src/tools/clangrefactoringbackend/clangrefactoringbackendmain.cpp
@@ -131,8 +131,10 @@ struct Data // because we have a cycle dependency
 };
 
 #ifdef Q_OS_WIN
+extern "C" void OutputDebugStringW(const wchar_t* msg);
 static void messageOutput(QtMsgType type, const QMessageLogContext &, const QString &msg)
 {
+    OutputDebugStringW(msg.toStdWString().c_str());
     std::wcout << msg.toStdWString() << std::endl;
     if (type == QtFatalMsg)
         abort();