From fcc2c95421710f98c7b2dec73e2c8b0d9164bc9b Mon Sep 17 00:00:00 2001 From: Jonathan Liu Date: Wed, 24 Aug 2016 11:18:37 +1000 Subject: Workaround crashes in QtQml code related to dead-store elimination When compiled in release mode with GCC 6, QtQml may crash. This is because the C++ compiler is more aggressive about dead-store elimination in situations where a memory store to a location precedes the construction of an object at that memory location. The QV4::MemoryManager::allocate{Managed,Object} functions allocate memory and write to it before the caller does a placement new to construct an object in the same memory. The compiler considers these writes before the constructor as "dead stores" and eliminates them. The -fno-lifetime-dse compiler flag is added to disable this more aggressive dead-store eliminiation optimization. This is a temporary workaround until a proper solution is found. Task-number: QTBUG-55482 Change-Id: I7dbae6e9e613e53ce5fb25957c449bc6657803b5 Reviewed-by: Thiago Macieira --- src/qml/qml.pro | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src') diff --git a/src/qml/qml.pro b/src/qml/qml.pro index f4862a17a6..651afa6b75 100644 --- a/src/qml/qml.pro +++ b/src/qml/qml.pro @@ -18,7 +18,7 @@ exists("qqml_enable_gcov") { greaterThan(QT_GCC_MAJOR_VERSION, 5) { # Our code is bad. Temporary workaround. - QMAKE_CXXFLAGS += -fno-delete-null-pointer-checks + QMAKE_CXXFLAGS += -fno-delete-null-pointer-checks -fno-lifetime-dse } QMAKE_DOCS = $$PWD/doc/qtqml.qdocconf -- cgit v1.2.3