From 42aba3076dc9b6c4f8f35dd79cbf2992f7373d4f Mon Sep 17 00:00:00 2001
From: Robin Burchell <robin.burchell@viroteck.net>
Date: Fri, 19 Dec 2014 20:45:55 +0100
Subject: QQmlJS::Codegen: Short circuit in qmlErrors to avoid QUrl allocation
 costs.

This takes the time taken in qmlErrors for my (admittedly terribly morbid)
testcase from ~104ms to ~1ms.

Change-Id: I288086caa6e6b58f67e9feb6f1761c3310f01ead
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
---
 src/qml/compiler/qv4codegen.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/qml/compiler/qv4codegen.cpp b/src/qml/compiler/qv4codegen.cpp
index bb27d897a6..ba4c450aae 100644
--- a/src/qml/compiler/qv4codegen.cpp
+++ b/src/qml/compiler/qv4codegen.cpp
@@ -2841,6 +2841,11 @@ QList<QQmlJS::DiagnosticMessage> Codegen::errors() const
 QList<QQmlError> Codegen::qmlErrors() const
 {
     QList<QQmlError> qmlErrors;
+
+    // Short circuit to avoid costly (de)heap allocation of QUrl if there are no errors.
+    if (_errors.size() == 0)
+        return qmlErrors;
+
     qmlErrors.reserve(_errors.size());
 
     QUrl url(_fileNameIsUrl ? QUrl(_module->fileName) : QUrl::fromLocalFile(_module->fileName));
-- 
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