Avoid lookup calls for constant values of the global object

undefined, Infinity and NaN can never be changed in the global
object, so we can directly resolve them to constants in the
parser.

Change-Id: I0cf43ff299518921d914121e150bc64ae5ea0c6e
Reviewed-by: Erik Verbruggen <erik.verbruggen@qt.io>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/qml/compiler/qv4codegen.cpp b/src/qml/compiler/qv4codegen.cpp
index 362f85c67e..a91a6e62e0 100644
--- a/src/qml/compiler/qv4codegen.cpp
+++ b/src/qml/compiler/qv4codegen.cpp
@@ -1358,6 +1358,14 @@ Codegen::Reference Codegen::referenceForName(const QString &name, bool isLhs)
     }
 
     if (!c->parent && !c->forceLookupByName() && _context->compilationMode != EvalCode && c->compilationMode != QmlBinding) {
+        // these value properties of the global object are immutable, we we can directly convert them
+        // to their numeric value here
+        if (name == QStringLiteral("undefined"))
+            return Reference::fromConst(this, Encode::undefined());
+        else if (name == QStringLiteral("Infinity"))
+            return Reference::fromConst(this, Encode(qInf()));
+        else if (name == QStringLiteral("Nan"))
+            return Reference::fromConst(this, Encode(qQNaN()));
         Reference r = Reference::fromName(this, name);
         r.global = true;
         return r;