ProjectExplorer: Fix Clang toolchain setup on Windows

Clang toolchain in gcc mode requires mingw sysroot and target
in order to be used properly on Windows.
Requires Qt >= 5.12 to work properly (it has the required mkspec).

Change-Id: I4e5a734c699ac98740c0d50560aa7b69751ae58c
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/cmakeprojectmanager/cmakebuildconfiguration.cpp

@@ -40,6 +40,7 @@
 #include <projectexplorer/buildmanager.h>
 #include <projectexplorer/buildsteplist.h>
 #include <projectexplorer/kit.h>
+#include <projectexplorer/kitinformation.h>
 #include <projectexplorer/projectexplorer.h>
 #include <projectexplorer/projectexplorerconstants.h>
 #include <projectexplorer/projectmacroexpander.h>
@@ -500,6 +501,18 @@ CMakeBuildInfo *CMakeBuildConfigurationFactory::createBuildInfo(const ProjectExp
     if (!buildTypeItem.isNull())
         info->configuration.append(buildTypeItem);
 
+    const QString sysRoot = SysRootKitInformation::sysRoot(k).toString();
+    if (!sysRoot.isEmpty()) {
+        info->configuration.append(CMakeConfigItem("CMAKE_SYSROOT", sysRoot.toUtf8()));
+        ProjectExplorer::ToolChain *tc = ProjectExplorer::ToolChainKitInformation::toolChain(
+            k, ProjectExplorer::Constants::CXX_LANGUAGE_ID);
+        if (tc) {
+            const QByteArray targetTriple = tc->originalTargetTriple().toUtf8();
+            info->configuration.append(CMakeConfigItem("CMAKE_C_COMPILER_TARGET", targetTriple));
+            info->configuration.append(CMakeConfigItem("CMAKE_CXX_COMPILER_TARGET ", targetTriple));
+        }
+    }
+
     return info;
 }
 

src/plugins/projectexplorer/gcctoolchain.cpp

@@ -43,6 +43,7 @@
 #include <utils/synchronousprocess.h>
 
 #include <QBuffer>
+#include <QComboBox>
 #include <QCoreApplication>
 #include <QDir>
 #include <QFileInfo>
@@ -74,6 +75,7 @@ static const char compilerPlatformLinkerFlagsKeyC[] = "ProjectExplorer.GccToolCh
 static const char targetAbiKeyC[] = "ProjectExplorer.GccToolChain.TargetAbi";
 static const char originalTargetTripleKeyC[] = "ProjectExplorer.GccToolChain.OriginalTargetTriple";
 static const char supportedAbisKeyC[] = "ProjectExplorer.GccToolChain.SupportedAbis";
+static const char parentToolChainIdKeyC[] = "ProjectExplorer.ClangToolChain.ParentToolChainId";
 static const char binaryRegexp[] = "(?:^|-|\\b)(?:gcc|g\\+\\+|clang(?:\\+\\+)?)(?:-([\\d.]+))?$";
 
 static QByteArray runGcc(const FileName &gcc, const QStringList &arguments, const QStringList &env)
@@ -1042,8 +1044,8 @@ QList<ToolChain *> GccToolChainFactory::autoDetectToolChain(const FileName &comp
 
 GccToolChainConfigWidget::GccToolChainConfigWidget(GccToolChain *tc) :
     ToolChainConfigWidget(tc),
-    m_compilerCommand(new PathChooser),
-    m_abiWidget(new AbiWidget)
+    m_abiWidget(new AbiWidget),
+    m_compilerCommand(new PathChooser)
 {
     Q_ASSERT(tc);
 
@@ -1083,8 +1085,10 @@ void GccToolChainConfigWidget::applyImpl()
     Q_ASSERT(tc);
     QString displayName = tc->displayName();
     tc->setCompilerCommand(m_compilerCommand->fileName());
+    if (m_abiWidget) {
         tc->setSupportedAbis(m_abiWidget->supportedAbis());
         tc->setTargetAbi(m_abiWidget->currentAbi());
+    }
     tc->setOriginalTargetTriple(tc->detectSupportedAbis().originalTargetTriple);
     tc->setDisplayName(displayName); // reset display name
     tc->setPlatformCodeGenFlags(splitString(m_platformCodeGenFlagsLineEdit->text()));
@@ -1108,24 +1112,29 @@ void GccToolChainConfigWidget::setFromToolchain()
     m_compilerCommand->setFileName(tc->compilerCommand());
     m_platformCodeGenFlagsLineEdit->setText(QtcProcess::joinArgs(tc->platformCodeGenFlags()));
     m_platformLinkerFlagsLineEdit->setText(QtcProcess::joinArgs(tc->platformLinkerFlags()));
+    if (m_abiWidget) {
         m_abiWidget->setAbis(tc->supportedAbis(), tc->targetAbi());
         if (!m_isReadOnly && !m_compilerCommand->path().isEmpty())
             m_abiWidget->setEnabled(true);
     }
+}
 
 bool GccToolChainConfigWidget::isDirtyImpl() const
 {
     auto tc = static_cast<GccToolChain *>(toolChain());
     Q_ASSERT(tc);
     return m_compilerCommand->fileName() != tc->compilerCommand()
-            || m_platformCodeGenFlagsLineEdit->text() != QtcProcess::joinArgs(tc->platformCodeGenFlags())
-            || m_platformLinkerFlagsLineEdit->text() != QtcProcess::joinArgs(tc->platformLinkerFlags())
-            || m_abiWidget->currentAbi() != tc->targetAbi();
+           || m_platformCodeGenFlagsLineEdit->text()
+                  != QtcProcess::joinArgs(tc->platformCodeGenFlags())
+           || m_platformLinkerFlagsLineEdit->text()
+                  != QtcProcess::joinArgs(tc->platformLinkerFlags())
+           || (m_abiWidget && m_abiWidget->currentAbi() != tc->targetAbi());
 }
 
 void GccToolChainConfigWidget::makeReadOnlyImpl()
 {
     m_compilerCommand->setReadOnly(true);
+    if (m_abiWidget)
         m_abiWidget->setEnabled(false);
     m_platformCodeGenFlagsLineEdit->setEnabled(false);
     m_platformLinkerFlagsLineEdit->setEnabled(false);
@@ -1150,6 +1159,9 @@ QStringList GccToolChainConfigWidget::splitString(const QString &s)
 
 void GccToolChainConfigWidget::handleCompilerCommandChange()
 {
+    if (!m_abiWidget)
+        return;
+
     bool haveCompiler = false;
     Abi currentAbi = m_abiWidget->currentAbi();
     bool customAbi = m_abiWidget->isCustomAbi() && m_abiWidget->isEnabled();
@@ -1207,12 +1219,75 @@ void GccToolChainConfigWidget::handlePlatformLinkerFlagsChange()
 // ClangToolChain
 // --------------------------------------------------------------------------
 
+static QList<ToolChain *> mingwToolChains()
+{
+    return ToolChainManager::toolChains([](const ToolChain *tc) -> bool {
+        return tc->typeId() == Constants::MINGW_TOOLCHAIN_TYPEID;
+    });
+}
+
+static const MingwToolChain *mingwToolChainFromId(const QByteArray &id)
+{
+    if (id.isEmpty())
+        return nullptr;
+
+    for (const ToolChain *tc : mingwToolChains()) {
+        if (tc->id() == id)
+            return static_cast<const MingwToolChain *>(tc);
+    }
+
+    return nullptr;
+}
+
+void ClangToolChain::syncAutodetectedWithParentToolchains()
+{
+    if (!HostOsInfo::isWindowsHost() || !isAutoDetected())
+        return;
+
+    QObject::disconnect(m_thisToolchainRemovedConnection);
+    QObject::disconnect(m_mingwToolchainAddedConnection);
+
+    if (!mingwToolChainFromId(m_parentToolChainId)) {
+        const QList<ToolChain *> mingwTCs = mingwToolChains();
+        m_parentToolChainId = mingwTCs.isEmpty() ? "" : mingwTCs.front()->id();
+    }
+
+    // Subscribe only autodetected toolchains.
+    ToolChainManager *tcManager = ToolChainManager::instance();
+    m_mingwToolchainAddedConnection
+        = QObject::connect(tcManager, &ToolChainManager::toolChainAdded, [this](ToolChain *tc) {
+              if (tc->typeId() == Constants::MINGW_TOOLCHAIN_TYPEID
+                  && !mingwToolChainFromId(m_parentToolChainId)) {
+                  m_parentToolChainId = tc->id();
+              }
+          });
+    m_thisToolchainRemovedConnection
+        = QObject::connect(tcManager, &ToolChainManager::toolChainRemoved, [this](ToolChain *tc) {
+              if (tc == this) {
+                  QObject::disconnect(m_thisToolchainRemovedConnection);
+                  QObject::disconnect(m_mingwToolchainAddedConnection);
+              } else if (m_parentToolChainId == tc->id()) {
+                  const QList<ToolChain *> mingwTCs = mingwToolChains();
+                  m_parentToolChainId = mingwTCs.isEmpty() ? "" : mingwTCs.front()->id();
+              }
+          });
+}
+
 ClangToolChain::ClangToolChain(Detection d) :
     GccToolChain(Constants::CLANG_TOOLCHAIN_TYPEID, d)
-{ }
+{
+    syncAutodetectedWithParentToolchains();
+}
 
 ClangToolChain::ClangToolChain(Core::Id typeId, ToolChain::Detection d) :
     GccToolChain(typeId, d)
+{
+    syncAutodetectedWithParentToolchains();
+}
+
+ClangToolChain::ClangToolChain(const ClangToolChain &other)
+    : GccToolChain(other)
+    , m_parentToolChainId(other.m_parentToolChainId)
 {}
 
 QString ClangToolChain::typeDisplayName() const
@@ -1261,22 +1336,30 @@ WarningFlags ClangToolChain::warningFlags(const QStringList &cflags) const
 FileNameList ClangToolChain::suggestedMkspecList() const
 {
     Abi abi = targetAbi();
-    if (abi.os() == Abi::DarwinOS)
+    if (abi.os() == Abi::DarwinOS) {
         return FileNameList()
                 << FileName::fromLatin1("macx-clang")
                 << FileName::fromLatin1("macx-clang-32")
                 << FileName::fromLatin1("unsupported/macx-clang")
                 << FileName::fromLatin1("macx-ios-clang");
-    else if (abi.os() == Abi::LinuxOS)
+    } else if (abi.os() == Abi::LinuxOS) {
         return FileNameList()
                 << FileName::fromLatin1("linux-clang")
                 << FileName::fromLatin1("unsupported/linux-clang");
+    } else if (abi.os() == Abi::WindowsOS) {
+        return FileNameList() << FileName::fromLatin1("win32-clang-g++");
+    }
     return FileNameList(); // Note: Not supported by Qt yet, so default to the mkspec the Qt was build with
 }
 
 void ClangToolChain::addToEnvironment(Environment &env) const
 {
     GccToolChain::addToEnvironment(env);
+
+    const QString sysroot = sysRoot();
+    if (!sysroot.isEmpty())
+        env.prependOrSetPath(sysroot + "/bin");
+
     // Clang takes PWD as basis for debug info, if set.
     // When running Qt Creator from a shell, PWD is initially set to an "arbitrary" value.
     // Since the tools are not called through a shell, PWD is never changed to the actual cwd,
@@ -1284,6 +1367,47 @@ void ClangToolChain::addToEnvironment(Environment &env) const
     env.unset("PWD");
 }
 
+QString ClangToolChain::originalTargetTriple() const
+{
+    const MingwToolChain *parentTC = mingwToolChainFromId(m_parentToolChainId);
+    if (parentTC)
+        return parentTC->originalTargetTriple();
+
+    return GccToolChain::originalTargetTriple();
+}
+
+QString ClangToolChain::sysRoot() const
+{
+    const MingwToolChain *parentTC = mingwToolChainFromId(m_parentToolChainId);
+    if (!parentTC)
+        return QString();
+
+    const FileName mingwCompiler = parentTC->compilerCommand();
+    return mingwCompiler.parentDir().parentDir().toString();
+}
+
+std::unique_ptr<ToolChainConfigWidget> ClangToolChain::createConfigurationWidget()
+{
+    return std::make_unique<ClangToolChainConfigWidget>(this);
+}
+
+QVariantMap ClangToolChain::toMap() const
+{
+    QVariantMap data = GccToolChain::toMap();
+    data.insert(parentToolChainIdKeyC, m_parentToolChainId);
+    return data;
+}
+
+bool ClangToolChain::fromMap(const QVariantMap &data)
+{
+    if (!GccToolChain::fromMap(data))
+        return false;
+
+    m_parentToolChainId = data.value(parentToolChainIdKeyC).toByteArray();
+    syncAutodetectedWithParentToolchains();
+    return true;
+}
+
 LanguageExtensions ClangToolChain::defaultLanguageExtensions() const
 {
     return LanguageExtension::Gnu;
@@ -1341,6 +1465,7 @@ QList<ToolChain *> ClangToolChainFactory::autoDetect(const QList<ToolChain *> &a
                                         hostAbi, Constants::C_LANGUAGE_ID,
                                         Constants::CLANG_TOOLCHAIN_TYPEID, alreadyKnown));
     }
+
     return tcs;
 }
 
@@ -1363,6 +1488,118 @@ GccToolChain *ClangToolChainFactory::createToolChain(bool autoDetect)
     return new ClangToolChain(autoDetect ? ToolChain::AutoDetection : ToolChain::ManualDetection);
 }
 
+ClangToolChainConfigWidget::ClangToolChainConfigWidget(ClangToolChain *tc) :
+    GccToolChainConfigWidget(tc)
+{
+    if (!HostOsInfo::isWindowsHost())
+        return;
+
+    // Remove m_abiWidget row because the parent toolchain abi is going to be used.
+    m_mainLayout->removeRow(m_mainLayout->rowCount() - 2);
+    m_abiWidget = nullptr;
+
+    m_parentToolchainCombo = new QComboBox(this);
+    m_mainLayout->insertRow(m_mainLayout->rowCount() - 1,
+                            tr("Parent Toolchain:"),
+                            m_parentToolchainCombo);
+
+    ToolChainManager *tcManager = ToolChainManager::instance();
+    m_parentToolChainConnections.append(
+        connect(tcManager, &ToolChainManager::toolChainUpdated, this, [this](ToolChain *tc) {
+            if (tc->typeId() == Constants::MINGW_TOOLCHAIN_TYPEID)
+                updateParentToolChainComboBox();
+        }));
+    m_parentToolChainConnections.append(
+        connect(tcManager, &ToolChainManager::toolChainAdded, this, [this](ToolChain *tc) {
+            if (tc->typeId() == Constants::MINGW_TOOLCHAIN_TYPEID)
+                updateParentToolChainComboBox();
+        }));
+    m_parentToolChainConnections.append(
+        connect(tcManager, &ToolChainManager::toolChainRemoved, this, [this](ToolChain *tc) {
+            if (tc->id() == toolChain()->id()) {
+                for (QMetaObject::Connection &connection : m_parentToolChainConnections)
+                    QObject::disconnect(connection);
+                return;
+            }
+            if (tc->typeId() == Constants::MINGW_TOOLCHAIN_TYPEID)
+                updateParentToolChainComboBox();
+        }));
+
+    setFromClangToolchain();
+}
+
+void ClangToolChainConfigWidget::updateParentToolChainComboBox()
+{
+    auto *tc = static_cast<ClangToolChain *>(toolChain());
+    QByteArray parentId = m_parentToolchainCombo->currentData().toByteArray();
+    if (tc->isAutoDetected() || m_parentToolchainCombo->count() == 0)
+        parentId = tc->m_parentToolChainId;
+
+    const MingwToolChain *parentTC = mingwToolChainFromId(parentId);
+
+    m_parentToolchainCombo->clear();
+    m_parentToolchainCombo->addItem(parentTC ? parentTC->displayName() : "",
+                                    parentTC ? parentId : "");
+
+    if (tc->isAutoDetected())
+        return;
+
+    for (const ToolChain *mingwTC : mingwToolChains()) {
+        if (parentId != mingwTC->id())
+            m_parentToolchainCombo->addItem(mingwTC->displayName(), mingwTC->id());
+    }
+}
+
+void ClangToolChainConfigWidget::setFromClangToolchain()
+{
+    GccToolChainConfigWidget::setFromToolchain();
+
+    if (m_parentToolchainCombo)
+        updateParentToolChainComboBox();
+}
+
+void ClangToolChainConfigWidget::applyImpl()
+{
+    GccToolChainConfigWidget::applyImpl();
+    if (!m_parentToolchainCombo)
+        return;
+
+    auto *tc = static_cast<ClangToolChain *>(toolChain());
+    tc->m_parentToolChainId.clear();
+
+    const QByteArray parentId = m_parentToolchainCombo->currentData().toByteArray();
+    if (!parentId.isEmpty()) {
+        for (const ToolChain *mingwTC : mingwToolChains()) {
+            if (parentId == mingwTC->id()) {
+                tc->m_parentToolChainId = mingwTC->id();
+                break;
+            }
+        }
+    }
+}
+
+bool ClangToolChainConfigWidget::isDirtyImpl() const
+{
+    if (GccToolChainConfigWidget::isDirtyImpl())
+        return true;
+
+    if (!m_parentToolchainCombo)
+        return false;
+
+    auto tc = static_cast<ClangToolChain *>(toolChain());
+    Q_ASSERT(tc);
+    const MingwToolChain *parentTC = mingwToolChainFromId(tc->m_parentToolChainId);
+    const QByteArray parentId = parentTC ? parentTC->id() : "";
+    return parentId != m_parentToolchainCombo->currentData();
+}
+
+void ClangToolChainConfigWidget::makeReadOnlyImpl()
+{
+    GccToolChainConfigWidget::makeReadOnlyImpl();
+    if (m_parentToolchainCombo)
+        m_parentToolchainCombo->setEnabled(false);
+}
+
 // --------------------------------------------------------------------------
 // MingwToolChain
 // --------------------------------------------------------------------------

src/plugins/projectexplorer/gcctoolchain.h

@@ -42,6 +42,7 @@ namespace ProjectExplorer {
 
 namespace Internal {
 class ClangToolChainFactory;
+class ClangToolChainConfigWidget;
 class GccToolChainConfigWidget;
 class GccToolChainFactory;
 class MingwToolChainFactory;
@@ -208,6 +209,7 @@ class PROJECTEXPLORER_EXPORT ClangToolChain : public GccToolChain
 public:
     explicit ClangToolChain(Detection d);
     ClangToolChain(Core::Id typeId, Detection d);
+    ClangToolChain(const ClangToolChain &other);
     QString typeDisplayName() const override;
     QString makeCommand(const Utils::Environment &environment) const override;
 
@@ -221,11 +223,25 @@ public:
     Utils::FileNameList suggestedMkspecList() const override;
     void addToEnvironment(Utils::Environment &env) const override;
 
+    QString originalTargetTriple() const override;
+    QString sysRoot() const override;
+
+    std::unique_ptr<ToolChainConfigWidget> createConfigurationWidget() override;
+
+    QVariantMap toMap() const override;
+    bool fromMap(const QVariantMap &data) override;
+
 protected:
     Utils::LanguageExtensions defaultLanguageExtensions() const override;
+    void syncAutodetectedWithParentToolchains();
 
 private:
+    QByteArray m_parentToolChainId;
+    QMetaObject::Connection m_mingwToolchainAddedConnection;
+    QMetaObject::Connection m_thisToolchainRemovedConnection;
+
     friend class Internal::ClangToolChainFactory;
+    friend class Internal::ClangToolChainConfigWidget;
     friend class ToolChainFactory;
 };
 

src/plugins/projectexplorer/gcctoolchainfactories.h

@@ -40,6 +40,7 @@ QT_END_NAMESPACE
 namespace Utils { class PathChooser; }
 
 namespace ProjectExplorer {
+class ClangToolChain;
 class GccToolChain;
 
 namespace Internal {
@@ -91,7 +92,7 @@ public:
     explicit GccToolChainConfigWidget(GccToolChain *tc);
     static QStringList splitString(const QString &s);
 
-private:
+protected:
     void handleCompilerCommandChange();
     void handlePlatformCodeGenFlagsChange();
     void handlePlatformLinkerFlagsChange();
@@ -103,15 +104,39 @@ private:
 
     void setFromToolchain();
 
+    AbiWidget *m_abiWidget;
+
+private:
     Utils::PathChooser *m_compilerCommand;
     QLineEdit *m_platformCodeGenFlagsLineEdit;
     QLineEdit *m_platformLinkerFlagsLineEdit;
-    AbiWidget *m_abiWidget;
 
     bool m_isReadOnly = false;
     ProjectExplorer::Macros m_macros;
 };
 
+// --------------------------------------------------------------------------
+// ClangToolChainConfigWidget
+// --------------------------------------------------------------------------
+
+class ClangToolChainConfigWidget : public GccToolChainConfigWidget
+{
+    Q_OBJECT
+public:
+    explicit ClangToolChainConfigWidget(ClangToolChain *tc);
+
+private:
+    void applyImpl() override;
+    void discardImpl() override { setFromClangToolchain(); }
+    bool isDirtyImpl() const override;
+    void makeReadOnlyImpl() override;
+
+    void setFromClangToolchain();
+    void updateParentToolChainComboBox();
+    QList<QMetaObject::Connection> m_parentToolChainConnections;
+    QComboBox *m_parentToolchainCombo = nullptr;
+};
+
 // --------------------------------------------------------------------------
 // ClangToolChainFactory
 // --------------------------------------------------------------------------

src/plugins/projectexplorer/kitinformation.cpp

@@ -121,12 +121,33 @@ Utils::FileName SysRootKitInformation::sysRoot(const Kit *k)
 {
     if (!k)
         return Utils::FileName();
+
+    if (!k->value(SysRootKitInformation::id()).toString().isEmpty())
         return Utils::FileName::fromString(k->value(SysRootKitInformation::id()).toString());
+
+    for (ToolChain *tc : ToolChainKitInformation::toolChains(k)) {
+        if (!tc->sysRoot().isEmpty())
+            return Utils::FileName::fromString(tc->sysRoot());
+    }
+
+    return Utils::FileName();
 }
 
 void SysRootKitInformation::setSysRoot(Kit *k, const Utils::FileName &v)
 {
-    if (k)
+    if (!k)
+        return;
+
+    for (ToolChain *tc : ToolChainKitInformation::toolChains(k)) {
+        if (!tc->sysRoot().isEmpty()) {
+            // It's the sysroot from toolchain, don't set it.
+            if (tc->sysRoot() == v.toString())
+                return;
+
+            // We've changed the default toolchain sysroot, set it.
+            break;
+        }
+    }
     k->setValue(SysRootKitInformation::id(), v.toString());
 }
 

src/plugins/projectexplorer/toolchain.cpp

@@ -362,6 +362,11 @@ QList<Task> ToolChain::validateKit(const Kit *) const
     return QList<Task>();
 }
 
+QString ToolChain::sysRoot() const
+{
+    return QString();
+}
+
 /*!
     \class ProjectExplorer::ToolChainFactory
     \brief The ToolChainFactory class creates tool chains from settings or

src/plugins/projectexplorer/toolchain.h

@@ -110,6 +110,7 @@ public:
 
     virtual Utils::LanguageExtensions languageExtensions(const QStringList &cxxflags) const = 0;
     virtual WarningFlags warningFlags(const QStringList &cflags) const = 0;
+    virtual QString sysRoot() const;
 
     class MacroInspectionReport
     {

src/plugins/qmakeprojectmanager/qmakestep.cpp

@@ -145,8 +145,14 @@ QMakeStepConfig QMakeStep::deducedArguments() const
     ProjectExplorer::ToolChain *tc
             = ProjectExplorer::ToolChainKitInformation::toolChain(kit, ProjectExplorer::Constants::CXX_LANGUAGE_ID);
     ProjectExplorer::Abi targetAbi;
-    if (tc)
+    if (tc) {
         targetAbi = tc->targetAbi();
+        if (HostOsInfo::isWindowsHost()
+            && tc->typeId() == ProjectExplorer::Constants::CLANG_TOOLCHAIN_TYPEID) {
+            config.sysRoot = ProjectExplorer::SysRootKitInformation::sysRoot(kit).toString();
+            config.targetTriple = tc->originalTargetTriple();
+        }
+    }
 
     BaseQtVersion *version = QtKitInformation::qtVersion(target()->kit());
 
@@ -902,5 +908,16 @@ QStringList QMakeStepConfig::toArguments() const
     if (separateDebugInfo)
         arguments << "CONFIG+=force_debug_info" << "CONFIG+=separate_debug_info";
 
+    if (!sysRoot.isEmpty()) {
+        arguments << ("QMAKE_CFLAGS+=--sysroot=\"" + sysRoot + "\"");
+        arguments << ("QMAKE_CXXFLAGS+=--sysroot=\"" + sysRoot + "\"");
+        arguments << ("QMAKE_LFLAGS+=--sysroot=\"" + sysRoot + "\"");
+        if (!targetTriple.isEmpty()) {
+            arguments << ("QMAKE_CFLAGS+=--target=" + targetTriple);
+            arguments << ("QMAKE_CXXFLAGS+=--target=" + targetTriple);
+            arguments << ("QMAKE_LFLAGS+=--target=" + targetTriple);
+        }
+    }
+
     return arguments;
 }

src/plugins/qmakeprojectmanager/qmakestep.h

@@ -76,6 +76,8 @@ public:
     QStringList toArguments() const;
 
     // Actual data
+    QString sysRoot;
+    QString targetTriple;
     TargetArchConfig archConfig = NoArch;
     OsType osType = NoOsType;
     bool linkQmlDebuggingQQ2 = false;