Prevent CoW detaches from happening

Change-Id: Ia42c0d732e0f6ccfa2c70b86edccd9eb471aac7c
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

2 files changed, 16 insertions, 13 deletions

diff --git a/src/qml/compiler/qv4compilerscanfunctions.cpp b/src/qml/compiler/qv4compilerscanfunctions.cpp
index 04593f202a..8984b6931e 100644
--- a/src/qml/compiler/qv4compilerscanfunctions.cpp
+++ b/src/qml/compiler/qv4compilerscanfunctions.cpp
@@ -741,9 +741,9 @@ void ScanFunctions::calcEscapingVariables()
         if (c->contextType != ContextType::ESModule)
             continue;
         for (const auto &entry: c->exportEntries) {
-            auto m = c->members.find(entry.localName);
-            if (m != c->members.end())
-                m->canEscape = true;
+            auto mIt = c->members.constFind(entry.localName);
+            if (mIt != c->members.constEnd())
+                mIt->canEscape = true;
         }
         break;
     }
@@ -759,8 +759,8 @@ void ScanFunctions::calcEscapingVariables()
             }
             Q_ASSERT(c != inner);
             while (c) {
-                Context::MemberMap::const_iterator it = c->members.find(var);
-                if (it != c->members.end()) {
+                Context::MemberMap::const_iterator it = c->members.constFind(var);
+                if (it != c->members.constEnd()) {
                     if (c->parent || it->isLexicallyScoped()) {
                         it->canEscape = true;
                         c->requiresExecutionContext = true;
@@ -816,15 +816,17 @@ void ScanFunctions::calcEscapingVariables()
             // add an escaping 'this' variable
             c->addLocalVar(QStringLiteral("this"), Context::VariableDefinition, VariableScope::Let);
             c->requiresExecutionContext = true;
-            auto m = c->members.find(QStringLiteral("this"));
-            m->canEscape = true;
+            auto mIt = c->members.constFind(QStringLiteral("this"));
+            Q_ASSERT(mIt != c->members.constEnd());
+            mIt->canEscape = true;
         }
         if (c->innerFunctionAccessesNewTarget) {
             // add an escaping 'new.target' variable
             c->addLocalVar(QStringLiteral("new.target"), Context::VariableDefinition, VariableScope::Let);
             c->requiresExecutionContext = true;
-            auto m = c->members.find(QStringLiteral("new.target"));
-            m->canEscape = true;
+            auto mIt = c->members.constFind(QStringLiteral("new.target"));
+            Q_ASSERT(mIt != c->members.constEnd());
+            mIt->canEscape = true;
         }
         if (c->allVarsEscape && c->contextType == ContextType::Block && c->members.isEmpty())
             c->allVarsEscape = false;
@@ -845,8 +847,9 @@ void ScanFunctions::calcEscapingVariables()
         }
         if (c->contextType == ContextType::Block && c->isCatchBlock) {
             c->requiresExecutionContext = true;
-            auto m = c->members.find(c->caughtVariable);
-            m->canEscape = true;
+            auto mIt = c->members.constFind(c->caughtVariable);
+            Q_ASSERT(mIt != c->members.constEnd());
+            mIt->canEscape = true;
         }
         const QLatin1String exprForOn("expression for on");
         if (c->contextType == ContextType::Binding && c->name.length() > exprForOn.size() &&
@@ -855,7 +858,7 @@ void ScanFunctions::calcEscapingVariables()
             // we don't know if the code is a signal handler or not.
             c->requiresExecutionContext = true;
         if (c->allVarsEscape) {
-            for (auto &m : c->members)
+            for (const auto &m : qAsConst(c->members))
                 m.canEscape = true;
         }
     }
diff --git a/src/qml/jsruntime/qv4identifiertable.cpp b/src/qml/jsruntime/qv4identifiertable.cpp
index e476baa886..4305bc4647 100644
--- a/src/qml/jsruntime/qv4identifiertable.cpp
+++ b/src/qml/jsruntime/qv4identifiertable.cpp
@@ -70,7 +70,7 @@ IdentifierTable::~IdentifierTable()
 {
     free(entriesByHash);
     free(entriesById);
-    for (auto &h : idHashes)
+    for (const auto &h : qAsConst(idHashes))
         h->identifierTable = nullptr;
 }