Avoid -Wshorten-64-to-32 warnings in a few places

...by explictily casting to int. Add a few comments explaining why we
can get at most INT_MAX many elements, and add Q_ASSERTS to check that
the assumptions actually hold.

Task-number: QTBUG-105055
Change-Id: I1769318a9c04b51efe45fe0cae9fc0d93cfec45e
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

6 files changed, 22 insertions, 10 deletions

diff --git a/src/qml/common/qv4compileddata_p.h b/src/qml/common/qv4compileddata_p.h
index f2adced909..93183865e7 100644
--- a/src/qml/common/qv4compileddata_p.h
+++ b/src/qml/common/qv4compileddata_p.h
@@ -231,7 +231,9 @@ struct String
     qint32_le size;
 
     static int calculateSize(const QString &str) {
-        return (sizeof(String) + (str.size() + 1) * sizeof(quint16) + 7) & ~0x7;
+        // we cannot enconuter strings larger than INT_MAX anyway, as such a string
+        // would already break in other parts of the compilation process
+        return (sizeof(String) + (int(str.size()) + 1) * sizeof(quint16) + 7) & ~0x7;
     }
 };
 
diff --git a/src/qml/common/qv4staticvalue_p.h b/src/qml/common/qv4staticvalue_p.h
index 001666d08a..896a31bdf2 100644
--- a/src/qml/common/qv4staticvalue_p.h
+++ b/src/qml/common/qv4staticvalue_p.h
@@ -167,7 +167,7 @@ struct StaticValue
     };
 
     inline Type type() const {
-        int t = quickType();
+        auto t = quickType();
         if (t < QT_Empty)
             return _val ? Managed_Type : Undefined_Type;
         if (t > QT_Int)
diff --git a/src/qml/jsruntime/qv4string_p.h b/src/qml/jsruntime/qv4string_p.h
index a546da1ea7..78727bdcc3 100644
--- a/src/qml/jsruntime/qv4string_p.h
+++ b/src/qml/jsruntime/qv4string_p.h
@@ -130,7 +130,8 @@ Q_STATIC_ASSERT(std::is_trivial_v<ComplexString>);
 
 inline
 int String::length() const {
-    return subtype < StringType_AddedString ? text().size : static_cast<const ComplexString *>(this)->len;
+    // TODO: ensure that our strings never actually grow larger than INT_MAX
+    return subtype < StringType_AddedString ? int(text().size) : static_cast<const ComplexString *>(this)->len;
 }
 
 }
diff --git a/src/qml/memory/qv4mmdefs_p.h b/src/qml/memory/qv4mmdefs_p.h
index 395f0870e4..c873bfd5f8 100644
--- a/src/qml/memory/qv4mmdefs_p.h
+++ b/src/qml/memory/qv4mmdefs_p.h
@@ -178,17 +178,17 @@ struct HeapItem {
 
     bool isGray() const {
         Chunk *c = chunk();
-        uint index = this - c->realBase();
+        std::ptrdiff_t index = this - c->realBase();
         return Chunk::testBit(c->grayBitmap, index);
     }
     bool isBlack() const {
         Chunk *c = chunk();
-        uint index = this - c->realBase();
+        std::ptrdiff_t index = this - c->realBase();
         return Chunk::testBit(c->blackBitmap, index);
     }
     bool isInUse() const {
         Chunk *c = chunk();
-        uint index = this - c->realBase();
+        std::ptrdiff_t index = this - c->realBase();
         return Chunk::testBit(c->objectBitmap, index);
     }
 
@@ -207,10 +207,10 @@ struct HeapItem {
     // Doesn't report correctly for huge items
     size_t size() const {
         Chunk *c = chunk();
-        uint index = this - c->realBase();
+        std::ptrdiff_t index = this - c->realBase();
         Q_ASSERT(Chunk::testBit(c->objectBitmap, index));
         // ### optimize me
-        uint end = index + 1;
+        std::ptrdiff_t end = index + 1;
         while (end < Chunk::NumSlots && Chunk::testBit(c->extendsBitmap, end))
             ++end;
         return (end - index)*sizeof(HeapItem);
diff --git a/src/qml/qml/qqmlcontext_p.h b/src/qml/qml/qqmlcontext_p.h
index 5489afb892..aeaa1a3cd5 100644
--- a/src/qml/qml/qqmlcontext_p.h
+++ b/src/qml/qml/qqmlcontext_p.h
@@ -50,7 +50,11 @@ public:
     int notifyIndex() const { return m_notifyIndex; }
     void setNotifyIndex(int notifyIndex) { m_notifyIndex = notifyIndex; }
 
-    int numPropertyValues() const { return m_propertyValues.size(); }
+    int numPropertyValues() const {
+        auto size = m_propertyValues.size();
+        Q_ASSERT(size <= std::numeric_limits<int>::max());
+        return int(size);
+    }
     void appendPropertyValue(const QVariant &value) { m_propertyValues.append(value); }
     void setPropertyValue(int index, const QVariant &value) { m_propertyValues[index] = value; }
     QVariant propertyValue(int index) const { return m_propertyValues[index]; }
diff --git a/src/qml/qml/qqmlpropertycachevector_p.h b/src/qml/qml/qqmlpropertycachevector_p.h
index 6386795086..a208b3fa6e 100644
--- a/src/qml/qml/qqmlpropertycachevector_p.h
+++ b/src/qml/qml/qqmlpropertycachevector_p.h
@@ -36,7 +36,10 @@ public:
         return data.resize(size);
     }
 
-    int count() const { return data.size(); }
+    int count() const {
+        // the property cache vector will never contain more thant INT_MAX many elements
+        return int(data.size());
+    }
     void clear()
     {
         for (int i = 0; i < data.size(); ++i) {
@@ -55,12 +58,14 @@ public:
         cache->addref();
         data.append(QBiPointer<const QQmlPropertyCache, QQmlPropertyCache>(cache.data()));
         Q_ASSERT(data.last().isT1());
+        Q_ASSERT(data.size() <= std::numeric_limits<int>::max());
     }
 
     void appendOwn(const QQmlPropertyCache::Ptr &cache) {
         cache->addref();
         data.append(QBiPointer<const QQmlPropertyCache, QQmlPropertyCache>(cache.data()));
         Q_ASSERT(data.last().isT2());
+        Q_ASSERT(data.size() <= std::numeric_limits<int>::max());
     }
 
     QQmlPropertyCache::ConstPtr at(int index) const