[LibertyClk] Support for Liberty file defined generated clock by markram1729 · Pull Request #378 · parallaxsw/OpenSTA

markram1729 · 2026-02-08T18:43:33Z

from silimate Opensta pull Adds support for Liberty file-defined generated clocks in OpenSTA, including new classes, functions, and tests.

Behavior:
- Adds support for Liberty file-defined generated clocks in LibertyReader.cc and Liberty.cc.
- Introduces GeneratedClock class in GeneratedClock.hh and GeneratedClock.cc to represent generated clocks.
- Updates Sta class in Sta.cc to handle generated clocks, including functions like updateGeneratedClks() and setUpdateGenclks().
Functions:
- Adds makeGeneratedClock() in Liberty.cc to create generated clock objects.
- Implements createLibertyGeneratedClocks() in Sdc.cc to create generated clocks from Liberty definitions.
- Modifies VerilogReader.cc to map generated clock pins to Liberty cells.
Tests:
- Adds test files generated_clock.lib, generated_clock.tcl, generated_clock.v, and generated_clock.ok to verify generated clock functionality.
- Updates regression_vars.tcl to include generated_clock test.

markram1729 · 2026-02-08T18:50:17Z

I will make changes to the formatting that is suitable for opensta

jjcherry56 · 2026-02-08T22:34:32Z

The first step is to remove all of the formatting changes that completely obscure the functional changes.

* fix : compilation * fix tcl commands * Update Network.cc

jjcherry56 · 2026-02-25T16:34:22Z

-static bool
-isPowerOfTwo(int i)
+bool
+isPowerofTwo(int i)


restore the original name that uses camel case

jjcherry56 · 2026-02-25T16:35:09Z

 		      float fanout);
  void setMaxArea(float area);
  float maxArea() const;
+  void createLibertyGeneratedClocks(Clock *clk);


use make instead of create for naming consistency with the rest of the code

jjcherry56 · 2026-02-25T16:36:16Z

+
+namespace sta {
+
+class GeneratedClock


The name GeneratedClock is too generic, since there are already generated clocks in sdc.
I suggest LibertyGenClk. The other functions names should be updated to be consistent.

jjcherry56 · 2026-02-25T16:36:32Z

+{
+public:
+  ~GeneratedClock();
+  const char *name() const { return name_; }


use std::string

jjcherry56 · 2026-02-25T16:37:21Z


  // Build helpers.
+  void makeGeneratedClock(const char *name,
+			  const char *clock_pin,


use spaces for indentation (this changed with rel 3.0)

jjcherry56 · 2026-02-25T16:38:09Z

  int line_;
 };

+class GeneratedClockGroup


You don't need GeneratedClockGroup; you could use a GeneratedClock that is
not in the Liberty and then add it. But the state class will be unnecessary
with the new liberty reader.

jjcherry56 · 2026-02-25T16:39:41Z

+  if (sta->pins(clk)) {
+
+    // All pins along the clock network
+    const PinSet clkNetworkPins = *sta->pins(clk);


the variable is named like a function; use snake case

jjcherry56 · 2026-02-25T16:41:11Z

+    // The keys of generated_clock_pins_to_cells_
+    // (master clock pins) will be searched in the current clock network
+    for (const auto &entry : generated_clock_pins_to_cells) {
+      const char *pinName = entry.first;


use c++17 [pin_name, cell] syntax to avoid first and second.

pinName should be pin_name.
See doc/CodingGuidelines.txt

jjcherry56 · 2026-02-25T16:42:32Z

  clkHpinDisablesInvalid();
+
+  // Trigger update of generated clocks
+  Sta::sta()->setUpdateGenclks();


again, wrong to referencd Sta::sta()

jjcherry56 · 2026-02-25T16:43:33Z

  return $clks
 }

+# Get attribute


this has nothing to do with generated clocks and has no business being here.

jjcherry56 · 2026-02-25T16:43:46Z

 define_cmd_args "get_name" {object}
 define_cmd_args "get_full_name" {object}

+#Get Object name


jjcherry56 · 2026-02-25T16:44:44Z

 define_cmd_args "get_full_name" {object}

+#Get Object name
+interp alias {} get_object_name {} get_full_name


put this in your .sta, not the sources

jjcherry56 · 2026-02-25T16:45:09Z

 }

 proc get_full_name { object } {
+  if { [llength $object] > 1 } {


jjcherry56 · 2026-02-25T16:46:08Z


+// Maps a clock pin path to the liberty cell containing the generated clock definition
+void
+VerilogReader::makeGeneratedClocks(LibertyCell *lib_cell, Instance *inst)


VerilogReader::makeGeneratedClocks makes no sense and violates modularity.
Generated clocks should work with a database that does not use the
verilog reader.

jjcherry56 · 2026-02-25T16:47:26Z

The Liberty reader is being rewritten so the parsing part of this will change rather drastically. It will probably be a week or so before those changes are pushed.

markram1729 added 6 commits February 6, 2026 10:40

init : generated Clock support headers

021e343

Add : Generated CLock to liberty cells

541116a

add : creating liberty defined generated clocks

96bf1d7

add : map generated clock pins to libery cells

3ada6ae

add : tests

7e2df0c

fix whitespace

d33b31d

markram1729 mentioned this pull request Feb 9, 2026

SMALL FIX Silimate/bounties#3

Open

markram1729 force-pushed the exLibertyClk branch from 37d5348 to d33b31d Compare February 16, 2026 05:57

fix : compilation , tcl commands

7257c45

* fix : compilation * fix tcl commands * Update Network.cc

markram1729 force-pushed the exLibertyClk branch from 61cbd89 to 7257c45 Compare February 16, 2026 06:13

jjcherry56 reviewed Feb 25, 2026

View reviewed changes

markram1729 added 3 commits March 6, 2026 16:59

fix : isPowerOfTwo

ae7bc70

fix : name

8608b9b

fix : trimstring

5f855ad

fix : tcl

3afa445

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jjcherry56 commented Feb 25, 2026

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markram1729 commented Feb 8, 2026 •

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