Merge remote-tracking branch 'origin/5.6' into 5.7

Conflicts:
	src/plugins/qmltooling/qmldbg_profiler/qqmlprofilerservice.cpp
	src/qml/jsruntime/qv4engine.cpp
	src/qml/jsruntime/qv4engine_p.h

Change-Id: I89ffccd699bee675732758d039e22224b275d60d

4 files changed, 39 insertions, 113 deletions

diff --git a/src/qml/jsruntime/qv4context_p.h b/src/qml/jsruntime/qv4context_p.h
index f51f677636..2e6773a927 100644
--- a/src/qml/jsruntime/qv4context_p.h
+++ b/src/qml/jsruntime/qv4context_p.h
@@ -247,7 +247,7 @@ struct WithContext : public ExecutionContext
     V4_MANAGED(WithContext, ExecutionContext)
 };
 
-struct QmlContext : public ExecutionContext
+struct Q_QML_EXPORT QmlContext : public ExecutionContext
 {
     V4_MANAGED(QmlContext, ExecutionContext)
 
diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index bc64bbfe06..b42dc37b0f 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -111,84 +111,6 @@ static ReturnedValue throwTypeError(CallContext *ctx)
     return ctx->engine()->throwTypeError();
 }
 
-const int MinimumStackSize = 256; // in kbytes
-
-QT_WARNING_PUSH
-QT_WARNING_DISABLE_MSVC(4172) // MSVC 2015: warning C4172: returning address of local variable or temporary: dummy
-
-quintptr getStackLimit()
-{
-    quintptr stackLimit;
-#if USE(PTHREADS) && !OS(QNX)
-#  if OS(DARWIN)
-    pthread_t thread_self = pthread_self();
-    void *stackTop = pthread_get_stackaddr_np(thread_self);
-    stackLimit = reinterpret_cast<quintptr>(stackTop);
-    quintptr size = 0;
-    if (pthread_main_np()) {
-        rlimit limit;
-        getrlimit(RLIMIT_STACK, &limit);
-        size = limit.rlim_cur;
-    } else
-        size = pthread_get_stacksize_np(thread_self);
-    stackLimit -= size;
-#  elif defined(__hppa)
-    // On some architectures the stack grows upwards. All of these are rather exotic, so simply assume
-    // everything is fine there.
-    // Known examples:
-    // -HP PA-RISC
-    stackLimit = 0;
-
-#  else
-    pthread_attr_t attr;
-#if HAVE(PTHREAD_NP_H) && OS(FREEBSD)
-    // on FreeBSD pthread_attr_init() must be called otherwise getting the attrs crashes
-    if (pthread_attr_init(&attr) == 0 && pthread_attr_get_np(pthread_self(), &attr) == 0) {
-#else
-    if (pthread_getattr_np(pthread_self(), &attr) == 0) {
-#endif
-        void *stackBottom = Q_NULLPTR;
-        size_t stackSize = 0;
-
-        pthread_attr_getstack(&attr, &stackBottom, &stackSize);
-        pthread_attr_destroy(&attr);
-
-#        if defined(Q_OS_ANDROID)
-        // Bionic pretends that the main thread has a tiny stack; work around it
-        if (gettid() == getpid()) {
-            rlimit limit;
-            getrlimit(RLIMIT_STACK, &limit);
-            stackBottom = reinterpret_cast<void*>(reinterpret_cast<quintptr>(stackBottom) + stackSize - limit.rlim_cur);
-        }
-#       endif
-
-        stackLimit = reinterpret_cast<quintptr>(stackBottom);
-    } else {
-        int dummy;
-        // this is inexact, as part of the stack is used when being called here,
-        // but let's simply default to 1MB from where the stack is right now
-        stackLimit = reinterpret_cast<qintptr>(&dummy) - 1024*1024;
-    }
-
-#  endif
-// This is wrong. StackLimit is the currently committed stack size, not the real end.
-// only way to get that limit is apparently by using VirtualQuery (Yuck)
-//#elif OS(WINDOWS)
-//    PNT_TIB tib = (PNT_TIB)NtCurrentTeb();
-//    stackLimit = static_cast<quintptr>(tib->StackLimit);
-#else
-    int dummy;
-    // this is inexact, as part of the stack is used when being called here,
-    // but let's simply default to 1MB from where the stack is right now
-    // (Note: triggers warning C4172 as of MSVC 2015, returning address of local variable)
-    stackLimit = reinterpret_cast<qintptr>(&dummy) - 1024*1024;
-#endif
-
-    // 256k slack
-    return stackLimit + MinimumStackSize*1024;
-}
-
-QT_WARNING_POP
 
 QJSEngine *ExecutionEngine::jsEngine() const
 {
@@ -200,9 +122,12 @@ QQmlEngine *ExecutionEngine::qmlEngine() const
     return v8Engine->engine();
 }
 
+qint32 ExecutionEngine::maxCallDepth = -1;
+
 ExecutionEngine::ExecutionEngine(EvalISelFactory *factory)
     : current(0)
     , hasException(false)
+    , callDepth(0)
     , memoryManager(new QV4::MemoryManager(this))
     , executableAllocator(new QV4::ExecutableAllocator)
     , regExpAllocator(new QV4::ExecutableAllocator)
@@ -219,6 +144,15 @@ ExecutionEngine::ExecutionEngine(EvalISelFactory *factory)
     , regExpCache(0)
     , m_multiplyWrappedQObjects(0)
 {
+    if (maxCallDepth == -1) {
+        bool ok = false;
+        maxCallDepth = qEnvironmentVariableIntValue("QV4_MAX_CALL_DEPTH", &ok);
+        if (!ok || maxCallDepth <= 0) {
+            maxCallDepth = 1234;
+        }
+    }
+    Q_ASSERT(maxCallDepth > 0);
+
     MemoryManager::GCBlocker gcBlocker(memoryManager);
 
     if (!factory) {
@@ -267,9 +201,6 @@ ExecutionEngine::ExecutionEngine(EvalISelFactory *factory)
 
     // set up stack limits
     jsStackLimit = jsStackBase + JSStackLimit/sizeof(Value);
-    cStackLimit = getStackLimit();
-    if (!recheckCStackLimits())
-        qFatal("Fatal: Not enough stack space available for QML. Please increase the process stack size to more than %d KBytes.", MinimumStackSize);
 
     identifierTable = new IdentifierTable(this);
 
@@ -1103,22 +1034,6 @@ QQmlError ExecutionEngine::catchExceptionAsQmlError()
     return error;
 }
 
-bool ExecutionEngine::recheckCStackLimits()
-{
-    int dummy;
-#ifdef Q_OS_WIN
-    // ### this is only required on windows, where we currently use heuristics to get the stack limit
-    if (cStackLimit - reinterpret_cast<quintptr>(&dummy) > 128*1024)
-        // we're more then 128k away from our stack limit, assume the thread has changed, and
-        // call getStackLimit
-#endif
-    // this can happen after a thread change
-    cStackLimit = getStackLimit();
-
-    return (reinterpret_cast<quintptr>(&dummy) >= cStackLimit);
-}
-
-
 // Variant conversion code
 
 typedef QSet<QV4::Heap::Object *> V4ObjectSet;
diff --git a/src/qml/jsruntime/qv4engine_p.h b/src/qml/jsruntime/qv4engine_p.h
index 7da4a1c3c1..73d506c4d2 100644
--- a/src/qml/jsruntime/qv4engine_p.h
+++ b/src/qml/jsruntime/qv4engine_p.h
@@ -81,15 +81,11 @@ namespace CompiledData {
 struct CompilationUnit;
 }
 
-#define CHECK_STACK_LIMITS(v4) \
-    if ((v4->jsStackTop <= v4->jsStackLimit) && (reinterpret_cast<quintptr>(&v4) >= v4->cStackLimit || v4->recheckCStackLimits())) {}  \
-    else \
-        return v4->throwRangeError(QStringLiteral("Maximum call stack size exceeded."))
-
-
 struct Q_QML_EXPORT ExecutionEngine
 {
 private:
+    static qint32 maxCallDepth;
+
     friend struct ExecutionContextSaver;
     friend struct ExecutionContext;
     friend struct Heap::ExecutionContext;
@@ -98,6 +94,7 @@ public:
 
     Value *jsStackTop;
     quint32 hasException;
+    qint32 callDepth;
 
     MemoryManager *memoryManager;
     ExecutableAllocator *executableAllocator;
@@ -107,7 +104,6 @@ public:
     ExecutionContext *currentContext;
 
     Value *jsStackLimit;
-    quintptr cStackLimit;
 
     WTF::BumpPointerAllocator *bumperPointerAllocator; // Used by Yarr Regex engine.
 
@@ -437,8 +433,6 @@ public:
 
     InternalClass *newClass(const InternalClass &other);
 
-    bool recheckCStackLimits();
-
     // Exception handling
     Value *exceptionValue;
     StackTrace exceptionStackTrace;
@@ -471,6 +465,8 @@ public:
     QV4::ReturnedValue metaTypeToJS(int type, const void *data);
 
     void assertObjectBelongsToEngine(const Heap::Base &baseObject);
+
+    bool checkStackLimits(ReturnedValue &exception);
 };
 
 inline void ExecutionEngine::pushContext(Heap::ExecutionContext *context)
@@ -516,7 +512,7 @@ inline Heap::QmlContext *ExecutionEngine::qmlContext() const
     if (ctx->type == Heap::ExecutionContext::Type_SimpleCallContext && !ctx->outer)
         ctx = parentContext(currentContext)->d();
 
-    if (!ctx->outer)
+    if (ctx->type != Heap::ExecutionContext::Type_QmlContext && !ctx->outer)
         return 0;
 
     while (ctx->outer && ctx->outer->type != Heap::ExecutionContext::Type_GlobalContext)
@@ -552,7 +548,26 @@ inline void Value::mark(ExecutionEngine *e)
         o->mark(e);
 }
 
+#define CHECK_STACK_LIMITS(v4) { ReturnedValue e; if ((v4)->checkStackLimits(e)) return e; } \
+    ExecutionEngineCallDepthRecorder _executionEngineCallDepthRecorder(v4);
+
+struct ExecutionEngineCallDepthRecorder
+{
+    ExecutionEngine *ee;
 
+    ExecutionEngineCallDepthRecorder(ExecutionEngine *e): ee(e) { ++ee->callDepth; }
+    ~ExecutionEngineCallDepthRecorder() { --ee->callDepth; }
+};
+
+inline bool ExecutionEngine::checkStackLimits(ReturnedValue &exception)
+{
+    if (Q_UNLIKELY((jsStackTop > jsStackLimit) || (callDepth >= maxCallDepth))) {
+        exception = throwRangeError(QStringLiteral("Maximum call stack size exceeded."));
+        return true;
+    }
+
+    return false;
+}
 
 } // namespace QV4
 
diff --git a/src/qml/jsruntime/qv4value_p.h b/src/qml/jsruntime/qv4value_p.h
index 514bdafb48..a8d9b0fa71 100644
--- a/src/qml/jsruntime/qv4value_p.h
+++ b/src/qml/jsruntime/qv4value_p.h
@@ -56,11 +56,7 @@
 #include "qv4global_p.h"
 #include <private/qv4heap_p.h>
 
-/* We cannot rely on QT_POINTER_SIZE to be set correctly on host builds. In qmldevtools the Value objects
-   are only used to store primitives, never object pointers. So we can use the 64-bit encoding. */
-#ifdef V4_BOOTSTRAP
-#define QV4_USE_64_BIT_VALUE_ENCODING
-#elif QT_POINTER_SIZE == 8
+#if QT_POINTER_SIZE == 8
 #define QV4_USE_64_BIT_VALUE_ENCODING
 #endif