ProjectExplorer: introduce Toolchain::priority

Can be used to prefer certain toolchain types over other if different
toolchains matches the same abi.

Change-Id: Ie1c62e8abfc98e8cda7f999c4df487799c8d4f13
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/projectexplorer/kitinformation.cpp

@@ -502,11 +502,13 @@ void ToolChainKitAspect::setup(Kit *k)
             [abi, l](const ToolChain *t) {
                 return t->targetAbi().toString() == abi && t->language() == l;
             });
-        Utils::sort(possibleTcs, [](const ToolChain *tc1, const ToolChain *tc2) {
-            return tc1->hostPrefersToolchain() && !tc2->hostPrefersToolchain();
-        });
-        if (!possibleTcs.isEmpty())
-            setToolChain(k, possibleTcs.first());
+        ToolChain *bestTc = nullptr;
+        for (ToolChain *tc : possibleTcs) {
+            if (!bestTc || tc->priority() > bestTc->priority())
+                bestTc = tc;
+        }
+        if (bestTc)
+            setToolChain(k, bestTc);
         else
             clearToolChain(k, l);
     }

src/plugins/projectexplorer/msvctoolchain.cpp

@@ -1746,6 +1746,11 @@ bool ClangClToolChain::operator==(const ToolChain &other) const
     return m_clangPath == clangClTc->m_clangPath;
 }
 
+int ClangClToolChain::priority() const
+{
+    return MsvcToolChain::priority() - 1;
+}
+
 Macros ClangClToolChain::msvcPredefinedMacros(const QStringList &cxxflags,
                                               const Utils::Environment &env) const
 {
@@ -2050,6 +2055,11 @@ bool MsvcToolChain::operator==(const ToolChain &other) const
            && m_varsBatArg == msvcTc->m_varsBatArg;
 }
 
+int MsvcToolChain::priority() const
+{
+    return hostPrefersToolchain() ? PriorityHigh : PriorityNormal;
+}
+
 void MsvcToolChain::cancelMsvcToolChainDetection()
 {
     envModThreadPool()->clear();

src/plugins/projectexplorer/msvctoolchain.h

@@ -98,6 +98,8 @@ public:
 
     bool isJobCountSupported() const override { return false; }
 
+    int priority() const override;
+
     static void cancelMsvcToolChainDetection();
     static Utils::optional<QString> generateEnvironmentSettings(const Utils::Environment &env,
                                                                 const QString &batchFile,
@@ -187,6 +189,8 @@ public:
 
     bool operator==(const ToolChain &) const override;
 
+    int priority() const override;
+
 private:
     QString m_clangPath;
 };

src/plugins/projectexplorer/toolchain.h

@@ -172,6 +172,14 @@ public:
     static Utils::LanguageVersion cxxLanguageVersion(const QByteArray &cplusplusMacroValue);
     static Utils::LanguageVersion languageVersion(const Utils::Id &language, const Macros &macros);
 
+    enum Priority {
+        PriorityLow = 0,
+        PriorityNormal = 10,
+        PriorityHigh = 20,
+    };
+
+    virtual int priority() const { return PriorityNormal; }
+
 protected:
     explicit ToolChain(Utils::Id typeId);
 

src/plugins/qtsupport/qtkitinformation.cpp

@@ -240,7 +240,7 @@ void QtKitAspect::fix(Kit *k)
                 return true;
             if (!tc1ExactMatch && tc2ExactMatch)
                 return false;
-            return tc1->hostPrefersToolchain() && !tc2->hostPrefersToolchain();
+            return tc1->priority() > tc2->priority();
         });
 
         const QList<ToolChain *> goodTcs = Utils::filtered(possibleTcs,