build: add bazel-orfs beta test for design builds

Add BUILD.bazel files for all asap7 and sky130hd designs using the
orfs_design() macro from bazel-orfs, which auto-generates flow targets
from existing config.mk files. Designs that don't yet work have the
orfs_design() call commented out with a note explaining what's missing
(typically a source BUILD.bazel with :verilog filegroup).

Working designs: gcd, gcd-ccs, aes, aes-block, aes-mbff, aes_lvt,
ethmac, ethmac_lvt (asap7); gcd, aes (sky130hd).

Includes bazel-orfs.md guide for beta testers. The full 51-design
patch set remains out-of-tree in bazel-orfs/orfs/ to minimize churn.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>

Author: oharboe

MODULE.bazel

@@ -11,10 +11,18 @@ bazel_dep(name = "bazel-orfs")
 # To bump version, run: bazelisk run @bazel-orfs//:bump
 git_override(
     module_name = "bazel-orfs",
-    commit = "f8a4b694b37c8f5322323eba9a9ae37f9541ee17",
+    commit = "e46fca0214def95ecfbada54a8028da7d47fd122",
     remote = "https://github.com/The-OpenROAD-Project/bazel-orfs.git",
 )
 
+# Transitive dep of bazel-orfs (lives in its verilog/ subdirectory).
+bazel_dep(name = "bazel-orfs-verilog")
+archive_override(
+    module_name = "bazel-orfs-verilog",
+    strip_prefix = "bazel-orfs-e46fca0214def95ecfbada54a8028da7d47fd122/verilog",
+    urls = ["https://github.com/The-OpenROAD-Project/bazel-orfs/archive/e46fca0214def95ecfbada54a8028da7d47fd122.tar.gz"],
+)
+
 bazel_dep(name = "rules_python", version = "1.2.0")
 bazel_dep(name = "rules_shell", version = "0.6.1")
 
@@ -36,12 +44,24 @@ orfs = use_extension("@bazel-orfs//:extension.bzl", "orfs_repositories")
 
 # To bump version, run: bazelisk run @bazel-orfs//:bump
 orfs.default(
-    image = "docker.io/openroad/orfs:v3.0-3273-gedf3d6bf",
+    image = "docker.io/openroad/orfs:26Q1-816-gf40d2f346",
     # Use local files instead of docker image
     makefile = "//flow:makefile",
     makefile_yosys = "//flow:makefile_yosys",
     pdk = "//flow:asap7",
-    sha256 = "f5692c6325ebcf27cc348e033355ec95c82c35ace1af7e72a0d352624ada143e",
+    sha256 = "2b05a14ae8062b4af82b245d648e95fa0293e09b61b57468518b66578744afb8",
+    variables_yaml = "//flow:scripts/variables.yaml",
 )
-use_repo(orfs, "com_github_nixos_patchelf_download")
 use_repo(orfs, "docker_orfs")
+
+# Auto-generate orfs_flow() targets from config.mk files.
+# See bazel-orfs.md for usage.
+orfs_designs = use_repo_rule("@bazel-orfs//private:designs.bzl", "orfs_designs")
+orfs_designs(
+    name = "orfs_designs",
+    designs_dir = "//flow/designs:BUILD.bazel",
+    platforms = [
+        "asap7",
+        "sky130hd",
+    ],
+)

bazel-orfs.md

@@ -0,0 +1,169 @@
+# bazel-orfs Beta Test
+
+This is an early integration of [bazel-orfs](https://github.com/The-OpenROAD-Project/bazel-orfs)
+into OpenROAD-flow-scripts. It lets you build ORFS designs with Bazel
+using the same `config.mk` files you already have.
+
+**Status**: beta -- a handful of simple designs work end-to-end.
+The full patch set lives out-of-tree in `bazel-orfs/orfs/` to minimize
+churn; this PR wires up the minimum needed for developers to kick the
+tires.
+
+## Quick Start
+
+```bash
+# Install bazelisk (one-time) -- see https://github.com/bazelbuild/bazelisk
+# Then, from the ORFS root:
+
+# Synthesize gcd on asap7 (downloads Docker image on first run)
+bazelisk build //flow/designs/asap7/gcd:gcd_synth
+
+# Run through floorplan
+bazelisk build //flow/designs/asap7/gcd:gcd_floorplan
+
+# Full flow through final
+bazelisk build //flow/designs/asap7/gcd:gcd_final
+
+# Run the test (includes QoR regression check)
+bazelisk test //flow/designs/asap7/gcd:gcd_test
+
+# List all targets for a design
+bazelisk query //flow/designs/asap7/gcd:all
+```
+
+## Available Targets Per Design
+
+Each enabled design gets these targets automatically from its `config.mk`:
+
+| Target suffix | What it does |
+|---|---|
+| `_synth` | Yosys synthesis |
+| `_floorplan` | Floorplan + I/O placement |
+| `_place` | Global + detailed placement |
+| `_cts` | Clock tree synthesis |
+| `_grt` | Global routing |
+| `_route` | Detailed routing |
+| `_final` | Final optimization + fill |
+| `_generate_abstract` | LEF/LIB abstract for hierarchical use |
+| `_generate_metadata` | Flow metadata (logs, reports) |
+| `_test` | Full flow + QoR regression check |
+
+Each stage depends on the previous one, so building `_final` runs the
+entire flow.
+
+## Working Designs
+
+These designs have `orfs_design()` enabled and pass `bazelisk query`:
+
+### asap7
+
+- `gcd` -- smoketest, builds in ~1 minute
+- `gcd-ccs` -- gcd with CCS lib model
+- `aes` (aes_cipher_top) -- medium design
+- `aes-block` -- aes as a block
+- `aes-mbff` -- aes with MBFF
+- `aes_lvt` -- aes with LVT cells
+- `ethmac` -- Ethernet MAC
+- `ethmac_lvt` -- ethmac with LVT cells
+
+### sky130hd
+
+- `gcd` -- smoketest
+- `aes` (aes_cipher_top) -- medium design
+
+## Designs Not Yet Working
+
+Each design directory has a `BUILD.bazel` with a commented-out
+`orfs_design()` call and a note explaining what's missing. The common
+blockers are:
+
+**Missing `src/` BUILD.bazel**: The source directory (e.g.
+`flow/designs/src/jpeg/`) needs a `BUILD.bazel` with a `:verilog`
+filegroup and `exports_files`. Affected: jpeg, jpeg_lvt, uart,
+riscv32i, riscv32i-mock-sram, mock-cpu, chameleon, microwatt.
+
+**Specific file references**: Some `config.mk` files reference
+individual source files instead of wildcards. These need
+`exports_files` in the source directory. Affected: ibex,
+swerv_wrapper.
+
+**Complex source trees**: Designs like cva6 have deeply nested source
+trees that each need their own `BUILD.bazel`. Affected: cva6.
+
+**Generated verilog**: mock-alu generates its verilog via Python scripts.
+Needs a `genrule`. Affected: mock-alu.
+
+**No config.mk**: mock-array has no config.mk (test fixture only).
+
+**No verilog**: minimal is a test design with no VERILOG_FILES.
+
+## How to Add More Designs
+
+1. Create `flow/designs/<platform>/<design>/BUILD.bazel`:
+
+```starlark
+load("@bazel-orfs//:openroad.bzl", "orfs_design")
+load("@orfs_designs//:designs.bzl", "DESIGNS")
+
+exports_files(glob(["*"]))
+
+orfs_design(designs = DESIGNS)
+```
+
+2. If `flow/designs/src/<name>/BUILD.bazel` doesn't exist, create it:
+
+```starlark
+exports_files(
+    glob(["*.v", "*.sv"], allow_empty = True),
+    visibility = ["//visibility:public"],
+)
+
+filegroup(
+    name = "verilog",
+    srcs = glob(include = ["*.v", "*.sv"], allow_empty = True),
+    visibility = ["//visibility:public"],
+)
+```
+
+3. Run `bazelisk query //flow/designs/<platform>/<design>:all` to verify.
+
+## Using a Local bazel-orfs Checkout
+
+To iterate on bazel-orfs rules locally, replace the `git_override` in
+`MODULE.bazel`:
+
+```starlark
+# Comment out the git_override block, then add:
+local_path_override(
+    module_name = "bazel-orfs",
+    path = "/path/to/your/bazel-orfs",
+)
+```
+
+Also update the `bazel-orfs-verilog` override:
+
+```starlark
+local_path_override(
+    module_name = "bazel-orfs-verilog",
+    path = "/path/to/your/bazel-orfs/verilog",
+)
+```
+
+## Key Differences from Make
+
+- **Incremental**: Bazel caches every stage. Changing `PLACE_DENSITY`
+  in `config.mk` rebuilds only floorplan onward -- synthesis is cached.
+- **Hermetic**: Tools come from a Docker image (extracted automatically).
+  No `make install` or `PATH` setup needed.
+- **Parallel**: Independent designs build in parallel automatically.
+- **Reproducible**: Same inputs always produce the same outputs.
+
+## Known Limitations
+
+- Only asap7 and sky130hd PDKs are wired up (others can be added to
+  `MODULE.bazel` platforms list and `flow/BUILD.bazel` orfs_pdk calls).
+- The Docker image is pinned; updating it requires changing
+  `MODULE.bazel`.
+- Not all designs work yet (see above).
+- This is a beta -- expect rough edges. File issues at
+  https://github.com/The-OpenROAD-Project/bazel-orfs/issues

flow/BUILD.bazel

@@ -14,6 +14,7 @@ filegroup(
     srcs = ["Makefile"],
     data = glob(MAKEFILE_SHARED + [
         "scripts/*.script",
+        "scripts/*.v",
         "scripts/util.tcl",
         "scripts/synth*.tcl",
         "platforms/common/**/*.v",

flow/designs/BUILD.bazel

@@ -0,0 +1 @@
+exports_files(["BUILD.bazel"])

flow/designs/asap7/aes-block/BUILD.bazel

@@ -0,0 +1,6 @@
+load("@bazel-orfs//:openroad.bzl", "orfs_design")
+load("@orfs_designs//:designs.bzl", "DESIGNS")
+
+exports_files(glob(["*"]))
+
+orfs_design(designs = DESIGNS)

flow/designs/asap7/aes-mbff/BUILD.bazel

@@ -0,0 +1,6 @@
+load("@bazel-orfs//:openroad.bzl", "orfs_design")
+load("@orfs_designs//:designs.bzl", "DESIGNS")
+
+exports_files(glob(["*"]))
+
+orfs_design(designs = DESIGNS)

flow/designs/asap7/aes/BUILD.bazel

@@ -0,0 +1,6 @@
+load("@bazel-orfs//:openroad.bzl", "orfs_design")
+load("@orfs_designs//:designs.bzl", "DESIGNS")
+
+exports_files(glob(["*"]))
+
+orfs_design(designs = DESIGNS)

flow/designs/asap7/aes_lvt/BUILD.bazel

@@ -0,0 +1,6 @@
+load("@bazel-orfs//:openroad.bzl", "orfs_design")
+load("@orfs_designs//:designs.bzl", "DESIGNS")
+
+exports_files(glob(["*"]))
+
+orfs_design(designs = DESIGNS)

flow/designs/asap7/cva6/BUILD.bazel

@@ -0,0 +1,9 @@
+load("@bazel-orfs//:openroad.bzl", "orfs_design")
+load("@orfs_designs//:designs.bzl", "DESIGNS")
+
+exports_files(glob(["*"]))
+
+# TODO(bazel-orfs): orfs_design(designs = DESIGNS)
+# Blocked: flow/designs/src/cva6/ needs BUILD.bazel with :verilog filegroup.
+# Complex multi-directory source tree with many subdirectories needing BUILD files.
+# Also needs BUILD.bazel for VERILOG_INCLUDE_DIRS targets.

flow/designs/asap7/ethmac/BUILD.bazel

@@ -0,0 +1,6 @@
+load("@bazel-orfs//:openroad.bzl", "orfs_design")
+load("@orfs_designs//:designs.bzl", "DESIGNS")
+
+exports_files(glob(["*"]))
+
+orfs_design(designs = DESIGNS)