Fix crashes on WinRT when allocation of executable memory is disabled

This regressed in commit b56f7d6f79b0de73c405b1503bfeb71ef5caf58f. We
need to choose the YARR JIT (as well as the regular JIT) only if we can
allocate executable memory.

Change-Id: I150238fda7b3699cb1d7ffedeeed3c6f3f54132b
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

4 files changed, 16 insertions, 6 deletions

diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index 259df976c5..ce29afdb6c 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -120,6 +120,9 @@ QQmlEngine *ExecutionEngine::qmlEngine() const
 #endif // V4_BOOTSTRAP
 
 qint32 ExecutionEngine::maxCallDepth = -1;
+#if defined(V4_ENABLE_JIT) && !defined(V4_BOOTSTRAP)
+const bool ExecutionEngine::canAllocateExecutableMemory = OSAllocator::canAllocateExecutableMemory();
+#endif
 
 ExecutionEngine::ExecutionEngine()
     : executableAllocator(new QV4::ExecutableAllocator)
diff --git a/src/qml/jsruntime/qv4engine_p.h b/src/qml/jsruntime/qv4engine_p.h
index c048f5f68d..930ad8fed1 100644
--- a/src/qml/jsruntime/qv4engine_p.h
+++ b/src/qml/jsruntime/qv4engine_p.h
@@ -484,10 +484,14 @@ public:
 
     bool checkStackLimits();
 
-    bool canJIT(Function *f)
+    bool canJIT(Function *f = nullptr)
     {
 #if defined(V4_ENABLE_JIT) && !defined(V4_BOOTSTRAP)
-        return f->interpreterCallCount >= jitCallCountThreshold;
+        if (!canAllocateExecutableMemory)
+            return false;
+        if (f)
+            return f->interpreterCallCount >= jitCallCountThreshold;
+        return true;
 #else
         Q_UNUSED(f);
         return false;
@@ -502,6 +506,9 @@ private:
     QScopedPointer<QV4::Profiling::Profiler> m_profiler;
 #endif
     int jitCallCountThreshold;
+#if defined(V4_ENABLE_JIT) && !defined(V4_BOOTSTRAP)
+    static const bool canAllocateExecutableMemory;
+#endif
 };
 
 // This is a trick to tell the code generators that functions taking a NoThrowContext won't
diff --git a/src/qml/jsruntime/qv4regexp.cpp b/src/qml/jsruntime/qv4regexp.cpp
index fb49def317..36616bc024 100644
--- a/src/qml/jsruntime/qv4regexp.cpp
+++ b/src/qml/jsruntime/qv4regexp.cpp
@@ -82,7 +82,7 @@ Heap::RegExp *RegExp::create(ExecutionEngine* engine, const QString& pattern, bo
         return result->d();
 
     Scope scope(engine);
-    Scoped<RegExp> result(scope, engine->memoryManager->alloc<RegExp>(pattern, ignoreCase, multiline, global));
+    Scoped<RegExp> result(scope, engine->memoryManager->alloc<RegExp>(engine, pattern, ignoreCase, multiline, global));
 
     result->d()->cache = cache;
     cachedValue.set(engine, result);
@@ -90,7 +90,7 @@ Heap::RegExp *RegExp::create(ExecutionEngine* engine, const QString& pattern, bo
     return result->d();
 }
 
-void Heap::RegExp::init(const QString &pattern, bool ignoreCase, bool multiline, bool global)
+void Heap::RegExp::init(ExecutionEngine *engine, const QString &pattern, bool ignoreCase, bool multiline, bool global)
 {
     Base::init();
     this->pattern = new QString(pattern);
@@ -106,7 +106,7 @@ void Heap::RegExp::init(const QString &pattern, bool ignoreCase, bool multiline,
         return;
     subPatternCount = yarrPattern.m_numSubpatterns;
 #if ENABLE(YARR_JIT)
-    if (!yarrPattern.m_containsBackreferences) {
+    if (!yarrPattern.m_containsBackreferences && engine->canJIT()) {
         jitCode = new JSC::Yarr::YarrCodeBlock;
         JSC::JSGlobalData dummy(internalClass->engine->regExpAllocator);
         JSC::Yarr::jitCompile(yarrPattern, JSC::Yarr::Char16, &dummy, *jitCode);
diff --git a/src/qml/jsruntime/qv4regexp_p.h b/src/qml/jsruntime/qv4regexp_p.h
index 94bebbd931..56454f73d3 100644
--- a/src/qml/jsruntime/qv4regexp_p.h
+++ b/src/qml/jsruntime/qv4regexp_p.h
@@ -76,7 +76,7 @@ struct RegExpCacheKey;
 namespace Heap {
 
 struct RegExp : Base {
-    void init(const QString& pattern, bool ignoreCase, bool multiline, bool global);
+    void init(ExecutionEngine *engine, const QString& pattern, bool ignoreCase, bool multiline, bool global);
     void destroy();
 
     QString *pattern;