V4: Add label for loop in spread in ArrayPattern

This patch also rotates the loop back so that the condition is at the
top of the loop. It's a cherry-picked from commit
0282b89ec672e25a465a8e51bc74c7fd58a624b1.

Without explicitly setting the label, we get a default constructed
Label from labelForOffset in PlatformAssemblerCommon::link, which leads
to a jump into nirvana.

This issue arises only with backward jumps, as we fill in the
information for forward jump targets once we actually encounter the
target.

Fixes: QTBUG-77047
Change-Id: Id928831f90eace494adb1eb1190f674a6f033b20
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/qml/compiler/qv4codegen.cpp b/src/qml/compiler/qv4codegen.cpp
index 61e37ffd25..5acc64bd81 100644
--- a/src/qml/compiler/qv4codegen.cpp
+++ b/src/qml/compiler/qv4codegen.cpp
@@ -1191,12 +1191,13 @@ bool Codegen::visit(ArrayPattern *ast)
                 ControlFlowLoop flow(this, &end, &in, cleanup);
 
                 in.link();
+                bytecodeGenerator->addLoopStart(in);
                 iterator.loadInAccumulator();
                 Instruction::IteratorNext next;
                 next.value = lhsValue.stackSlot();
                 next.done = iteratorDone.stackSlot();
                 bytecodeGenerator->addInstruction(next);
-                bytecodeGenerator->addTracingJumpInstruction(Instruction::JumpTrue()).link(end);
+                bytecodeGenerator->addJumpInstruction(Instruction::JumpTrue()).link(end);
 
                 lhsValue.loadInAccumulator();
                 pushAccumulator();