Merge remote-tracking branch 'origin/5.5' into 5.6

Conflicts:
	config.tests/common/atomic64/atomic64.cpp
	configure
	src/3rdparty/forkfd/forkfd.c
	src/corelib/io/forkfd_qt.cpp
	src/widgets/kernel/qwidgetwindow.cpp
	tests/auto/corelib/statemachine/qstatemachine/tst_qstatemachine.cpp
	tests/auto/network/socket/qtcpsocket/tst_qtcpsocket.cpp
	tests/auto/widgets/widgets/qcombobox/tst_qcombobox.cpp
	tools/configure/configureapp.cpp

Change-Id: Ic6168d82e51a0ef1862c3a63bee6722e8f138414

1 files changed, 6 insertions, 3 deletions

diff --git a/src/corelib/codecs/qutfcodec.cpp b/src/corelib/codecs/qutfcodec.cpp
index a64b3d167e..476990fb7a 100644
--- a/src/corelib/codecs/qutfcodec.cpp
+++ b/src/corelib/codecs/qutfcodec.cpp
@@ -363,6 +363,7 @@ QString QUtf8::convertToUnicode(const char *chars, int len, QTextCodec::Converte
     // main body, stateless decoding
     res = 0;
     const uchar *nextAscii = src;
+    const uchar *start = src;
     while (res >= 0 && src < end) {
         if (src >= nextAscii && simdDecodeAscii(dst, nextAscii, src, end))
             break;
@@ -371,9 +372,11 @@ QString QUtf8::convertToUnicode(const char *chars, int len, QTextCodec::Converte
         res = QUtf8Functions::fromUtf8<QUtf8BaseTraits>(ch, dst, src, end);
         if (!headerdone && res >= 0) {
             headerdone = true;
-            // eat the UTF-8 BOM
-            if (dst[-1] == 0xfeff)
-                --dst;
+            if (src == start + 3) { // 3 == sizeof(utf8-bom)
+                // eat the UTF-8 BOM (it can only appear at the beginning of the string).
+                if (dst[-1] == 0xfeff)
+                    --dst;
+            }
         }
         if (res == QUtf8BaseTraits::Error) {
             res = 0;