set_disable_clock_gating_check

[akashlevy]

No description provided.

[greptile-apps]

Greptile Summary

This PR implements set_disable_clock_gating_check as a proper SDC command (previously only the internal alias set_disable_inferred_clock_gating existed) and extends it to support liberty-cell objects in addition to instances and pins. The old name is retained as a backward-compatible alias. write_sdc serialization is also added for all three object types via the new writeDisabledClockGatingChecks() helper, and the instance-level query now inherits the cell-level disable correctly.

Confidence Score: 4/5

Safe to merge; only P2 style/robustness issues found, no logic or security bugs.

All findings are P2: non-deterministic sort order for same-named cells across libraries in write_sdc, and missing explanatory comments on two complex code blocks per the team's documentation rule. No P0 or P1 issues identified.

sdc/WriteSdc.cc — lib-cell sort comparator and missing comments on writeDisabledClockGatingChecks.

Important Files Changed

Filename	Overview
sdc/WriteSdc.cc	Adds writeDisabledClockGatingChecks() to serialize lib-cell, instance, and pin clock gating check disables; lib-cell sort uses only cell name, which could be non-deterministic for same-named cells across libraries.
sdc/Sdc.cc	Adds LibertyCell-level disable support: insert/erase/query for lib-cell set, and instance check now also queries cell set for inherited disable.
search/Search.tcl	Renames set_disable_inferred_clock_gating to set_disable_clock_gating_check; old name kept as a backward-compatible alias delegating to the new implementation; adds lib-cell and port handling.
include/sta/Sdc.hh	Declares new LibertyCell-overloaded disable/remove/query methods and adds the disabled_clk_gating_checks_lib_cell_ set member along with three new accessor methods.
search/Sta.cc	Forwards LibertyCell overloads of disableClockGatingCheck/removeDisableClockGatingCheck to sdc_ and invalidates endpoints.
sdc/Sdc.i	Adds SWIG bindings for disable_clock_gating_check_lib_cell and unset_disable_clock_gating_check_lib_cell, mirroring the existing inst/pin bindings.
sdc/WriteSdcPvt.hh	Adds declaration for the new writeDisabledClockGatingChecks() method.
test/disable_clock_gating_check.tcl	New regression test covering lib-cell, instance, pin, port, mixed, back-compat alias, and write_sdc round-trip for the new command.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["set_disable_clock_gating_check {objects}"] --> B{Object type}
    B -->|get_lib_cells| C["disable_clock_gating_check_lib_cell(cell)\n→ Sdc::disabled_clk_gating_checks_lib_cell_"]
    B -->|get_cells| D["disable_clock_gating_check_inst(inst)\n→ Sdc::disabled_clk_gating_checks_inst_"]
    B -->|get_pins| E["disable_clock_gating_check_pin(pin)\n→ Sdc::disabled_clk_gating_checks_pin_"]
    B -->|get_ports| F["disable_clock_gating_check_pin(get_port_pin)\n→ Sdc::disabled_clk_gating_checks_pin_"]
    G["GatedClk::isGatedClkEnable / gatedClkEnables"] --> H["isDisableClockGatingCheck(pin)"]
    G --> I["isDisableClockGatingCheck(inst)"]
    I --> J{inst in disabled_inst set?}
    J -->|yes| K[return true]
    J -->|no| L["network_->libertyCell(inst)"]
    L --> M{cell in disabled_cell set?}
    M -->|yes| K
    M -->|no| N[return false]
    O["write_sdc → writeDisabledClockGatingChecks()"] --> P["Write set_disable_clock_gating_check\nfor lib cells / instances / pins"]

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