+ Repository is now a Nix flake
~ Change all invocations of `openroad -python` to use `run_odbpy_script` for consistency
~ Change build system from ad-hoc to Nix, still producing a Docker image as a final result
~ Update KLayout scripts to use `klayout-pymod` or properly parse commandline arguments
~ `open_pdks` -> `bdc9412` to match OpenLane 2
- Remove local installer; `nix run .` will run OpenLane natively

~ Updated install documentation
~ Fixed issue where the issue survey's PDK checker uses `./pdks` instead of `~/.volare`
- Dropped `pip` requirement/check: `venv`s include `pip` regardless

As OpenLane 1 approaches a feature freeze, people who want new features should be going there more.

+ Add test for JSON config files
~ Updated various `rm` execs to `file delete -force`
~ Test script now outputs to stdout as well as a log file
~ Moved post-run hook runner to `all.tcl`
~ Moved installation docs to their own subcategory
~ Fix security bug

+ Add flag to enable/disable timing model generation after STA
+ Add both powered and unpowered netlists to `save_views`
+ Add multi-corner SDF and SPEF files to `save_views`
~ Fix #1413 and add regression test
~ Move `./run_issue_regressions.py` inside `tests` as a modular main function

~ Documentation all moved under `docs/source`, arranged hierarchically according to the table of contents
~ `Klayout` changed to `KLayout` in all logging messages
~ Readme rewritten to just be concise, parts of it isolated into standalone documentation
~ RTD builds no longer use conda (saves some time)
~ Fixed all broken links

~ `TEST_MISMATCHES` -> `./flow.tcl -test_mismatches <class>`
~ `QUIT_ON_MISMATCHES` o-> `./flow.tcl -ignore_mismatches`

+ Create new IR drop report generation step in the `signoff` stage
+ ALMOST ALL STEPS NOW PRINT THEIR LOGS' PATH
~ `increment_index/TIMER/set log/puts_info` commands organized across the board
~ Fix issue where `FP_PDN_AUTO_ADJUST` would not snap its values to the mfg grid
~ Reorder `configuration/general.tcl`
~ Update Contribution Guidelines
~ Various Docs Fixes
- Remove `FP_PDN_IRDROP`

~ RecommonMark, Sphinx Markdown Tables replaced with MyST Parser
~ All package versions pinned
~ Updated various broken links

+ Added PDK build instructions using Volare
~ Git requirement for general use (but not building) dropped from 2.35 -> 2.22
~ Fixed `override_env`'s inconsistent behavior (thanks, Tcl)
- Removed conda pdk installation vestiges
- Removed some useless and confusing under-the-hood sections

+ JSON Configs now support per-PDK and per-SCL options
+ JSON Configs now have a limited expression engine and a way to specify the current working directory and glob inside of it
+ Created script to help migrate tcl configs to json configs
+ `-init_design_config` rewritten, now creates an `openlane` folder inside the design's directory. New flag `-add_to_designs` restores the previous behavior
+ `docs/source/configuration_files.md` created with a focus on documenting how the configuration files work, including the JSON configuration files
~ Update `picorv32` design
~ Most `config.tcl`s replaced with `config.json` alternatives
~ Global configuration files now loaded in a specific order with no glob
~ Changed default values for PL_TARGET_DENSITY
~ Documentation updates to support the use of configuration JSON files as a first class citizen
~ Update author list
~ Replicate override_env after second design source
~ Move verify_mismatches to before most preparation
~ flow.tcl no longer requires `-design`, is happy to use the current working directory as a default
~ replicate.py rewritten
~ update.py not rewritten, but uses click now (and an improved --help)
- Removed "flag documentation" for some python scripts, just use `--help`

* Initial work on integrating volare

* CI

* More CI fixes

* Update opdks

* Switch to Efabless open_pdks fork, update

+ Added optional multiple **process corner** technology lef support (min/max/nom), in addition to the already existing multiple **timing corner** support (ss/tt/ff). This will also be our nomenclature going fwd.
+ Parasitics extraction now run at all process corners, and multi-corner analysis is run at all three process corners
~ `finishing` -> `signoff`
~ Parasitics extraction and STA are now an independent step instead of being lumped in routing, as part of the signoff block
~ Update OpenROAD
~ Update Open_PDKs, Sky130, and Magic
~ PDK verification made more PDK agnostic outside of env.py
~ Made RCX use LEF files instead of multiple configuration variables/set_rc.tcl
~ `prep_lefs` more or less rewritten
- Removed redundant RCX variables
- Removed `-order_wires` from various `read_def`s in OpenROAD- deprecated, apparently

+ `-verbose` flag added with multiple levels, replacing `-disable_output` (which is now the default behavior)
+ New command `puts_verbose` added, to be used for extra pieces of information
+ ./flow.tcl header now includes version, copyright and licensing information
+ Added `-last_run` flag allowing you to quickly resume the last run (useful with -interactive)
+ Added `open_in_klayout` command that lets you open the CURRENT_DEF in Klayout
~ `env.py issue-survey` now detects whether it's running inside the container and warns accordingly
~ RUN_KLAYOUT, RUN_KLAYOUT_DRC, RUN_MAGIC_DRC, RUN_LVS now only control noninteractive flows
~ Full git hash added to containers
~ Various Documentation Updates
~ Changed verbosity of various output messages
- Removed `-disable_output` (now the default behavior)
- Removed OpenLane ASCII art
- Removed various "chatty" messages, including things succeeding (shut up unless something fails)

This adds an issue-specific CI that can be used to test specific regressions rather than running entire flows.

Also, a partial solution for #892.

[skip ci]

Specify version of click required.
per - https://github.com/The-OpenROAD-Project/OpenLane/pull/933#issuecomment-1045921879

[skip ci]

Remove an unproven and oft unused utility from the OpenLane tree.

Some usability improvements for the sky130 PDK make targets in addition to code de-duplication.

~ `INSTALL_SRAM=enabled make pdk` removed in favor of `make pdk-with-sram`
~ `make full-pdk` removed in favor of `FULL_PDK=1 make pdk`
~ `make native-pdk` removed in favor of `NATIVE_PDK=1 make pdk`

+ Added linting rules for flake8, formatting with black
+ Added a GitHub Action to enforce lint/format rules

This restores `-save` functionality from previous versions of OpenLane, which was mistakenly removed.

+ run_designs.py now exits with exit code 2 if a design failed
~ run_designs.py rewritten in click, API altered slightly
~ renamed `addComputedStatistics` to `add_computed_statistics`
- removed `make regression_test`

~ CI now uploads each run tarball individually
~ Updated READMEs
~ `save_views` now always executed
- Removed `run_power_pins_insertion_step`: `write_powered_verilog` now run right before LVS

* Report Generation Bugfixes

+ Added `-override_env` option to flow.tcl to override certain environment variables on a per-run basis
+ Added option to extract inverter cells into the metrics behind an env var (so as not to break compatibility)
+ Klayout requirements added to runtime
~ Regression test outputs renamed, design report now in yaml
~ CI now runs on ubuntu-20.04 specifically, installs pyyaml
~ Fixed `make test`
~ Rewrote compare_regression_reports in click
~ Fixed compare_regression_design (typo made it not run, aliasing failures!!)
~ Changes to variable names: FINAL_TIMING_REPORT_TAG is now LAST_TIMING_REPORT_TAG, ran every STA
~ Fixed yosys gate type extraction

* Fix Odd Antenna Issue By Reverting OpenROAD

The best thing to happen to OpenLane since OpenLane.

Variables related to output files: i.e. logs, results and reports, are becoming more uniform.

* Variables now point to folders
* Variables now called `{stage}_{type}s`
* All variables renamed to be tool-generic
   * magic, klayout, cvc and lvs all unified, renamed "finishing"
* Better flow runtime calculation
  * All step runtimes are now stored in a yaml file, which can easily be read by a human or parsed by a computer.
* Better step indexing
   * You have to increment the step index explicitly using `increment_index`.
   * Functions that take log arguments now require you to not use an indexed file, it's their responsibility to index them.
* Changed names for many logs to make more sense
* A plethora of files being moved and/or renamed
   * Yosys scripts were moved into their own folder
   * All references to OpenLANE that are not a published paper have been replaced with OpenLane
   * Copyright dates updated on some files

* verilog2def -> init_floorplan

Some files still retained the name of a floorplanning tool we're no longer using. It has been removed.

* netlist locations

Netlists generated as part of later steps were placed under `synthesis/`. They have been moved to their proper locations.

* Build tweaks

`make openlane` now actually builds the container. `make pull-openlane` has been added with the original functionality.

The git commit has been placed in the container at `/git_version`.

A custom `.bashrc` has been added.

Non-standard `echo -ne` invocations replaced with `printf`.

* Issues

verify_versions now works without a `PDK_ROOT` set (`$openlane_root/pdks`)

clarified issue template

* Rewrite or_replace.tcl

That script used a lot of internal swig commands with an unstable API/unpredictable behavior. Resolves #697.

* Expose `max_displacement` flag for detailed placement

This was added at some point as a replacement to the diamond search height thing and is necessary for macros.

* Add OpenROAD GUI/Tcl Readline

Resolves #642. Note that this addition will be intentionally undocumented and is intended more for people who absolutely want it.

MISC:

* CI fast fail off/always push image

The CI will report failures still, but will still publish an image and create a tag. Additionally, other tests won't be killed  on the first failure.

* Naming convention changes

  * `docker_build/` -> `docker`: Just is more consistent with literally every other codebase that uses Docker ever.

  * Removed `or_` prefix from OpenROAD scripts: redundant: They're all already under a folder called "openroad." The distinction no longer makes any sense as there are no separate scripts for the previously standalone utilities.

This makes a number of internal improvements to the docker build process.

* A common build base

This common build base utilizes the dependency list outlined in `/dependencies` for both yum and pip, with the exception of cu-gr and dr-cu which use an... interesting (read: obtuse) build system. Speaking of...

* A pre-compile dependency list

This allows for the installing of dependencies that may need to be needed to compile *other* dependencies, incl. wheel, pyinstaller, devtoolset, etc.

* Builds now use tarballs

Git is no longer used, saving us the time needed to check out the *entire commit history every single time we build.* To handle submodules, I wrote a special script. Only OpenROAD uses submodules anyhow.

* Rewrote final image

The final image's Dockerfile was a mess. The new one also uses the dependency list and is better organized.

* OpenLane is now mounted to `/openlane` instead of `/openLANE_flow`

We don't really use `openLANE`, branding was settled on `OpenLane`, except I think it's better for everyone's sanity if I avoid capital letters altogether.

+ ./install.py greatly expanded to ./env.py, a python script consolidating all manners of environment configuration including installation and docker option generation
+ issues are now required to use ./env.py to survey the environment
+ installs to arch/manjaro now supported
~ python no longer asks to install, it creates a virtual environment
~ centos7 -> centos-7 (for consistency)
~ scripts reorganized: i need that top level as pristine as humanly possible
- removed csv2html. just use a viewer

Co-authored-by: Ahmed Nofal <ahmed.nofal@efabless.com>

This changes Makefile environment variables to be consistent with caravel user project based on feedback from @mattvenn.

Also, the fastest_test_set/extended_test_set productions have been fixed from a break in #627.

* IMAGE_NAME -> OPENLANE_IMAGE_NAME

* CURRENT_TAG -> OPENLANE_TAG

~ Reformatted run_designs.py to be more consistent with the rest of the codebase
~ Moved almost all top level scripts into other folders
~ Moved most top level documentation to docs/source
~ ol_install.py -> install.py
~ Fixed infinite recursion issue with or_issue.py

Also fixed minor issue with version verification in docker containers