Lib DB Gen

Owner roles: soc-synthesis-engineer, soc-low-power-engineer. MCP tools lib_db_convert and lib_db_stub are connected at the project parent for routing; execution remains restricted to those owners through named MCP inheritance.

Use this skill when a flow needs a Synopsys .db and only has either a Liberty .lib or an RTL top module whose ports should become a black-box stub cell.

Commands

The bundled script is scripts/lib_db_gen.py.

Convert an existing Liberty file to DB:

python3 .agents/skills/lib-db-gen/scripts/lib_db_gen.py convert \
  --lib path/to/input.lib \
  --db path/to/output.db

Generate an early black-box Liberty from a Verilog top and compile it to DB:

python3 .agents/skills/lib-db-gen/scripts/lib_db_gen.py stub \
  --top-v path/to/top.v \
  --top top_module_name \
  --lib path/to/top_stub.lib \
  --db path/to/top_stub.db

Use --no-run to only emit the .lib and convert Tcl. Use --work-dir <dir> for command files, logs, and any vendor crash snapshots (default <db-output-dir>/lc_work). Never launch dc_shell or lc_shell from the repository root; direct diagnostics must use a module de/run/<tool>/ directory or a gitignored tmp/eda/<tool>/ directory as the process working directory.

Shell backend (default: dc_shell)

Default is dc_shell + enable_write_lib_mode (env LIB_DB_SHELL_MODE=dc). This is the supported convert path: same .db as Library Compiler, exit 0 cleanly.

enable_write_lib_mode
read_lib "/path/to/input.lib"
write_lib <lib_name> -format db -output "/path/to/output.db"
exit

Set DC_SHELL or --dc-shell if dc_shell is not on PATH.

Optional backends (not recommended for day-to-day):

• --shell-mode auto — prefer DC, fall back to LC if DC is missing
• --shell-mode lc — use lc_shell (on some RHEL 8 + LC X-2025.06 hosts, write_lib succeeds then SIGSEGV in exit handlers; the wrapper may still accept a non-empty staged .db after a crash exit)

MCP tools accept shell_mode / dc_shell / lc_shell knobs; omit them to use the DC default.

The generated <db-stem>.lc.tcl is temporary by default: remove it only after a non-empty current-run .db is atomically installed at the requested output path, and retain it when conversion fails or --no-run is selected. Use --keep-tcl to preserve a reusable final-output command file after success. Use --tcl <path> only to override its location. Reject resolved-path collisions among Tcl, DB, Liberty, and Verilog inputs before writing any file.

Workflow

1. Prefer a real foundry or platform Liberty for timing signoff and mapped synthesis.
2. Use convert for real Liberty to .db conversion.
3. Use stub only for early integration, link, or black-box bring-up. The generated cell has ports and zero-area placeholder attributes; it is not timing or power evidence.
4. Keep generated .db, .lib, and LC logs out of Git unless they are reviewed release collateral.
5. For Design Compiler setup, point local ignored config such as scripts/local.mk at the generated .db, for example SKY130HD_DC_DB := /path/to/lib.db.

Notes

• stub parses ANSI-style module headers and simple non-ANSI declarations.
• Numeric packed ranges like [7:0] become Liberty bus types. Parameterized widths are treated as scalar with a warning; use a resolved wrapper if bus width fidelity matters.
• The generated stub DB is for black-box linking, not cell mapping. It does not replace a standard-cell target library.