I think that a fix is needed in OpenLane during GD...
# openlanem
Matthew Guthaus
06/21/2021, 4:03 PMI think that a fix is needed in OpenLane during GDS merge to prevent name conflicts in macros. (Or is this an OpenRoad problem?)
This came up with OpenRAM memories, but it is a larger concern for any hardened macro. If a user duplicates any module name anywhere in the hierarchy, only the last design is kept. Obviously, this is wanted in some cases, eg standard cells, for reuse but not in other designs.
I propose that we have a premerge processing where we add a unique suffix to any module, except the top one and if it is a standard cell.
Comments?
t
Tim Edwards
06/21/2021, 4:27 PMmagic's
gds uniqueTim Edwards
06/21/2021, 4:29 PMSo basically that does what you were suggesting except for the part about excluding cells like standard cells.
m
Matthew Guthaus
06/21/2021, 4:38 PMOk, OpenLane should add this for macros then? I can see a user having a conflict in their own designs...
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Tim Edwards
06/21/2021, 4:44 PMFirst it occurs to me to ask if you intended that this would be done on a GDS read or a GDS write.
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Matthew Guthaus
06/21/2021, 4:49 PMt
Tim Edwards
06/21/2021, 4:52 PMI see; it would be done during GDS write. That would be a new feature that needs to be implemented.
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Matthew Guthaus
06/21/2021, 4:55 PMI'm not clear how gds unique works. Is that during a read?
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Tim Edwards
06/21/2021, 4:55 PMYes, that's for GDS read.
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Matthew Guthaus
06/21/2021, 4:56 PMThat code reads in all the GDS files and then writes them, so it could be used there, right?
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Tim Edwards
06/21/2021, 4:58 PMI'm not sure it's implementing the behavior you want. In general, I'd say that it's not the responsibility of the library to produce unique names, it's the responsibility of whatever is reading cells from the library to ensure that they are properly handled if the names collide.
m
Matthew Guthaus
06/21/2021, 5:01 PMYes, I think that is why it should be there. This is what puts together the multiple macros/libraries. (Maybe we are talking around eachother?) Are EXTRA_GDS_FILES just the macros or libraries+macros?
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Tim Edwards
06/21/2021, 5:08 PMI don't know what EXTRA_GDS_FILES is. The script was written by the OpenLane developers, and they use way too many environment variables instead of making script arguments and options.
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Matthew Guthaus
06/21/2021, 5:10 PMI agree.
I believe it is what you specify in your config.tcl for an openlane project.
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`::env(EXTRA_GDS_FILES)` To point at the GDS files of the hardened macros.Matthew Guthaus
06/21/2021, 6:23 PMI think I see. Since we are reading in the def/lef and replacing with GDS, it seems like we cannot use gds unique because the names are already defined in the def/lef.
Matthew Guthaus
06/21/2021, 6:23 PMOr something... magic is just telling me that gds unique isn't an option when it is in the merge GDS script.
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Tim Edwards
06/21/2021, 7:15 PMThat's odd. It works for me.
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Matthew Guthaus
06/21/2021, 8:25 PMIn their script?
Matthew Guthaus
06/21/2021, 8:25 PMIt works for me outside of their script too
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Tim Edwards
06/21/2021, 8:29 PMWhat version of magic is the script running? It shouldn't simply not recognize a command option.
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Matthew Guthaus
06/21/2021, 8:30 PMIf I run magic in the docker, it is using 8.3.180. I'm not sure if they override that somehow
Matthew Guthaus
06/21/2021, 8:31 PM Copy code
"unique" isn't a valid gds option.
GDS commands have the form ":gds option", where option is one of:
help print this help information
addendum [yes|no] output only cells that are not type "readonly"
arrays [yes|no] output arrays as individual subuses (like in CIF)
contacts [yes|no] optimize output by arraying contacts as subcells
drccheck [yes|no] mark all cells as needing DRC checking
flatten [yes|no|limit] flatten simple cells (e.g., contacts) on input
flatglob [<name>|none] flatten cells by name with glob patterning
ordering [on|off] cause cells to be read in post-order
labels [yes|no] cause labels to be output when writing GDS-II
library [yes|no] do not output the top level, only subcells
lower [yes|no] allow both upper and lower case in labels
merge [yes|no] merge tiles into polygons in the output
nodatestamp [yes|no] write a zero value creation date stamp
noduplicates [yes|no] do not read cells that exist before reading GDS
read file read Calma GDS-II format from "file"
into edit cell
readonly [yes|no] set cell as read-only and generate output from GDS file
rescale [yes|no] allow or disallow internal grid subdivision
warning [option] set warning information level
write file output Calma GDS-II format to "file"
for the window's root cell
polygon subcells [yes|no]
put non-Manhattan polygons into subcells
path subcells [yes|no]
put wire paths into individual subcells
undefined [allow|disallow]
[dis]allow writing of GDS with calls to undefined cells
If no option is given, a CALMA GDS-II stream file is
produced for the root cell.
The current CIF output style ("cif ostyle") is used
to select the mask layers output by :gds write.
The current CIF input style ("cif istyle") is used
to select the mask layers read by :gds read.
[INFO]: Merging GDS /project/openlane/user_project_wrapper/../../gds/user_proj_example.gdst
Tim Edwards
06/21/2021, 8:33 PMIt must be using magic predating 8.3.160, then, which was April 28, so not all that long ago.
m
Matthew Guthaus
06/21/2021, 8:34 PMHm. This is the challenge with this flow, it isn't clear what it does behind the scenes in most cases 😞
Matthew Guthaus
06/21/2021, 8:36 PMI had upgraded it in the Docker image, but evidently it isn't found by the scripts.
Matthew Guthaus
06/21/2021, 8:38 PM$ more build/version/magic.version
Build Timestamp: 2021-06-18_17-37-00
f001502a1868977a4d9c9fc5a27c09b2589d744c
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