V4: Replace a QSet with a QVector in calculateOptionalJumps

Instead of storing a bunch of statement IDs in a QSet, the parent basic
block of the terminator statement (specifically: the jump) is used as
an index into a bit vector. If the bit is set, this indicates that the
jump can be omitted.

This reduces the number of allocations from 1 hash node per optional
jump, to 1 per function. The allocation will also be smaller then a
hash node.

Change-Id: Ia34468534b96dd9cefa837523bf89ad233de92e8
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/qml/jsruntime/qv4util_p.h b/src/qml/jsruntime/qv4util_p.h
index 59c12c5e46..2669a3e4bf 100644
--- a/src/qml/jsruntime/qv4util_p.h
+++ b/src/qml/jsruntime/qv4util_p.h
@@ -90,6 +90,9 @@ public:
         : bits(size, value)
     {}
 
+    void clear()
+    { bits = std::vector<bool>(bits.size(), false); }
+
     void reserve(int size)
     { bits.reserve(size); }
 
@@ -153,6 +156,9 @@ public:
         : bits(size, value)
     {}
 
+    void clear()
+    { bits = QBitArray(bits.size(), false); }
+
     void reserve(int size)
     { Q_UNUSED(size); }