d1eda66668
The only use for the clocker attribute and the AstVar::isUsedClock that is actually necessary today for correctness is to mark top level inputs of --lib-create blocks as being (or driving) a clock signal. Correctness of --lib-create (and hence hierarchical blocks) actually used to depend on having the right optimizations eliminate intermediate clocks (e.g.: V3Gate), when the top level port was not used directly in a sensitivity list, or marking top level signals manually via --clk or the clocker attribute. However V3Sched::partition already needs to trace through the logic to figure out what signals might drive a sensitivity list, so it can very easily mark all top level inputs as such. In this patch we remove the AstVar::attrClocker and AstVar::isUsedClock attributes, and replace them with AstVar::isPrimaryClock, automatically set by V3Sched::partition. This eliminates all need for manual annotation so we are deprecating the --clk/--no-clk options and the clocker/no_clocker attributes. This also eliminates the opportunity for any further mis-optimization similar to #6453. Regarding the other uses of the removed AstVar attributes: - As of 5.000, initial edges are triggered via a separate mechanism applied in V3Sched, so the use in V3EmitCFunc.cpp is redundant - Also as of 5.000, we can handle arbitrary sensitivity expressions, so the restriction on eliminating clock signals in V3Gate is unnecessary - Since the recent change when Dfg is applied after V3Scope, it does perform the equivalent of GateClkDecomp, so we can delete that pass. |
||
|---|---|---|
| .. | ||
| _static | ||
| bin | ||
| gen | ||
| guide | ||
| .gitignore | ||
| CONTRIBUTING.rst | ||
| CONTRIBUTORS | ||
| Makefile | ||
| README.rst | ||
| internals.rst | ||
| security.rst | ||
| spelling.txt | ||
| verilated.dox | ||
| xml.rst | ||
README.rst
Verilator Documentation ======================= This folder contains sources for Verilator documentation. For formatted documentation see: - `Verilator README <https://github.com/verilator/verilator>`_ - `Verilator installation and package directory structure <https://verilator.org/install>`_ - `Verilator manual (HTML) <https://verilator.org/verilator_doc.html>`_, or `Verilator manual (PDF) <https://verilator.org/verilator_doc.pdf>`_ - `Subscribe to Verilator announcements <https://github.com/verilator/verilator-announce>`_ - `Verilator forum <https://verilator.org/forum>`_ - `Verilator issues <https://verilator.org/issues>`_