KLayout
Wrong layer used when showing off a 'ROUTED' net from DEF that starts with a VIA
In the DEF you find :
NETS 1 ;
- testNet ( Mux1 A0 ) ( Mux1 S0 ) + USE SIGNAL
+ ROUTED li1 ( 209862 226950 ) L1M1_PR ( 212255 * ) L1M1_PR;
And this gets displayed as a horizontal wire in the li1 layer instead of the met1 layer.
From DEF specs :
viaName
Specifies a via to place at the last point. If you specify a via, layerName for the next routing coordinates (if any) is implicitly changed to the other routing layer for the via. For example, if the current layer is metal1, a via12 changes the layer to metal2 for the next routing coordinates.
So here the route starts on li1 (but doesn't actually have anything there) and directly goes through a via L1M1_PR (via from li1 to met1) and so the layer should switch to met1, go some distance on the X axis, then come down to li1 again via another via.
magic shows the trace on the met1 layer, but KLayout shows it on the li1 layer.
Files ( example DEF + tech LEF and lib LEF ) to reproduce :
@smunaut Thanks for the testcase and this bug report.
LEF/DEF is under heavy development currently. One reason is support for MASK separation and a variety of other topics. It turned out that LEF/DEF reading - which started rather naive - is actually far more difficult than expected. Along with other issues your bug is already fixed there: if you want to build KLayout yourself, you can try the "lefdef_enhancments" branch (sorry for the missing "e").
Unfortunately the changes are too big to be backported to 0.26, so the fix will only come in 0.27.
I have attached the DEF I have translated with this version. It shows the wire in the correct layer now.
Please note that KLayout will automatically read all LEF files next to your DEF, but it will look for *.lef, so it does not recognize *.tlef as a LEF file. If you rename it to ..._tech.lef, KLayout will read it together with your DEF without need to specify it explicitly.
Best regards,
Matthias
