Optimize memory consumption of ahead-of-time compile cache files

When loading a pre-compiled cache file, the strings contained therein
will remain available in memory since commit
7dcada48d2435e8ceb0cc8a6771f79b76979e11f. While for aot built cache
files we may have to add new strings (for example for signal handler
parameters), we can re-use the existing strings by omitting them from
the intermediately created string table.

This saves ~283K RAM with qtquickcontrols1 gallery.

Task-number: QTBUG-69588
Change-Id: I8ea807f6dea4cc35d8b7e5f7329809ed1cd12880
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 10 insertions, 0 deletions

diff --git a/tests/auto/qml/qmlcachegen/tst_qmlcachegen.cpp b/tests/auto/qml/qmlcachegen/tst_qmlcachegen.cpp
index fab33a4175..71e661e507 100644
--- a/tests/auto/qml/qmlcachegen/tst_qmlcachegen.cpp
+++ b/tests/auto/qml/qmlcachegen/tst_qmlcachegen.cpp
@@ -266,6 +266,16 @@ void tst_qmlcachegen::signalHandlerParameters()
         // (offsetToImports) should be the same _plus_ one entry in the newly added formals table.
         const quint32 sizeOfNewFormalsTable = 1 * sizeof(quint32);
         QCOMPARE(quint32(compilationUnit->unitData()->offsetToImports), oldImportsOffset + sizeOfNewFormalsTable);
+
+        // Typically the final file name is one of those strings that is not in the original
+        // pre-compiled qml file's string table, while for example the signal parameter
+        // name ("value") is.
+        const auto isStringIndexInOriginalStringTable = [compilationUnit](uint index) {
+            return index < compilationUnit->backingUnit->stringTableSize;
+        };
+
+        QVERIFY(isStringIndexInOriginalStringTable(compilationUnit->objectAt(0)->signalAt(0)->parameterAt(0)->nameIndex));
+        QVERIFY(!isStringIndexInOriginalStringTable(compilationUnit->unitData()->sourceFileIndex));
     }
 }