All code is built as C++ via CXX, but we still have some references to
CC. Trying to make sure we don't add plain C later by hiding the C
compiler. (So it's always enough to override CXX=... in configure)
Add an explicit 'sha' parameter to reusable-build, to define which
commit to build. This will be needed for PR coverage jobs. Consequently
use the 'archive' output from reusable-build to simplify retrieving the
resulting artifact in dependent jobs. Also fetch full history in
coverage builds.
The default timeout for a job in GitHub Actions is 6 hours, which is
both too long, but more importantly, when reached the job is 'cancelled'
instead of 'failed'. Use the new `--timeout` option on `rtlmeter run`
instead to add a 60 minute timeout to compile and execute steps. (This
is ~3x longer than recent worst runs in the CI)
Chores:
- Remove ci-ccache-maint. This has never been useful and is just cruft.
- Remove then unused CI_COMMIT
- Change job names so they come out nicer in the web views
- Make os-name input to reusable-build always explicit
Improvements:
- Have at most build-test job in progress per branch
- Cancel in-progress build-test jobs on PRs
- In forks (that is, not on 'verilator/verilator'), cancel any
in-progress build-test jobs on push to the branch
Workflows triggered for a PR from a fork can never have write
permissions, so to post a comment on a PR, it must be done from a
separate workflow triggered by 'workflow_run' in the main repository.
Runs RTLMeter on PRs if the PR has the 'pr: rtlmeter' label applied to
it. This should make it easy to selectively require the RTLMeter
workflows to pass on a PR that is potentially invasive, per our own
judgement.
The manual for the BLKANDNBLK warning describes that it is safe to
disable that error if the updated ranges are non-overlapping. This
however was not true (see the added t_nba_mixed_update* tests).
In this patch we change V3Delayed to use a new ShadowVarMasked
scheme for variables that have mixed blocking and non-blocking
updates (or the FlagUnique scheme for unpacked variables), which
is in fact safe to use when the updated parts are non-overlapping.
Furthermore, mixed assignments are safe as far as scheduling is
concerned if either:
- They are to independent parts (bits/members/etc) (with this patch)
- Or if the blocking assignment is in clocked (or suspendable) logic.
The risk in scheduling is a race between the Post scheduled NBA
commit, and blocking assignments in combinational logic, which might
order incorrectly.
The second point highlights that we can handle stuff like this safely,
which is sometimes used in testbenches:
```systemverilog
always @(posedge clk) begin
if ($time == 0) a = 0;
end
always @(posedge clk) begin
if ($time > 0) a <= 2;
end
````
The only dangerous case is:
```systemverilog
always @(posedge clk) foo[idx] <= val;
assign foo[0] = bar;
```
Whit this patch, this will still resolve fine at run-time if 'idx' is
never zero, but might resolve incorrectly if 'idx' is zero.
With the above in mind, the BLKANDNBLK warning is now only issued if:
- We can't prove that the assignments are to non-overlapping bits
- And the blocking assignment is in combinational logic
These are the cases that genuinely require user attention to resolve.
With this patch, there are no more BLKANDNBLK warnings in the RTLMeter
designs.
Fixes#6122.
Geza Lore
dependabot[bot]
Wilson Snyder
Lan Zongwei
Tobias Rosenkranz