* Don't invalidate ExtModule ports in an explicitInvalidate = true context

ExtModule ports were previously invalidated in the emitted FIRRTL, which is correct in a NonStrict / `Chisel._` compatibility context but not in newer chisel3 code where `explicitInvalidate = true`.

Don't modify the Builder prefix if reinvoking suggestName on a Data

Add utilities to enable backwards compatibility of the Trace.traceName
API to Chisel 3.5.x.  This adds a Trace.traceNameV2 utility which
aliases to Trace.traceName.  This also removes the TraceNameAnnotation
and renames it TraceAnnotation.  In 3.5.x, traceName will point at
TraceNameAnnotation (which has don't touch behavior) and will be
deprecated telling people to use traceNameV2 which will point at
TraceAnnotation (which does not have don't touch behavior).  This will
require fixups to the backport associated with this PR.

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>

There is a new trait, chisel3.experimental.AutoCloneType that is mixed
in to Bundle and can optionally be mixed in to user-defined Records. The
compiler plugin prints a deprecation warning on any user-defined
implementation of cloneType, telling the user to mix in AutoCloneType
before upgrading to 3.6.

Chisel 3.5.4 predates Scala 2.13.10 so the plugin is not published for 2.13.10.

2.13.9 has a binary compatibility regression so should be avoided.

Change the behavior of the Trace API to not have "don't touch" behavior
unconditionally.  Removing "don't touch" enables a finer granularity of
functionality: if a user wants "don't touch" they can add a "don't
touch".  However, they are not locked optimization blocking behavior
which may be undesirable in certain situations.

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>

Change the type of modules that the traceName API can be used for from
"Module" to "RawModule".  This fixes a bug where this API couldn't be
used for RawModules even though it totally works.

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>

* Add unit test for Issue 2760

* checkpoint: Fix for nested instance

* remove comments about stuff not working

* make the test check the output a little more

* relax the requirement on returning empty ioMap

* Update core/src/main/scala/chisel3/experimental/hierarchy/core/Lookupable.scala

* Update core/src/main/scala/chisel3/Data.scala

* Update core/src/main/scala/chisel3/experimental/hierarchy/core/Lookupable.scala

Co-authored-by: Jack Koenig <koenig@sifive.com>

* Update src/test/scala/chiselTests/experimental/hierarchy/InstanceSpec.scala

Co-authored-by: Jack Koenig <koenig@sifive.com>

* Update core/src/main/scala/chisel3/experimental/hierarchy/core/Lookupable.scala

* Add another unit test which unfortunately still passes

* Update core/src/main/scala/chisel3/Data.scala

* Update src/test/scala/chiselTests/experimental/hierarchy/InstanceSpec.scala

Co-authored-by: Jack Koenig <koenig@sifive.com>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

Co-authored-by: Jack Koenig <koenig@sifive.com>

Co-authored-by: Megan Wachs <megan@sifive.com>
Co-authored-by: Jack Koenig <koenig@sifive.com>

Use Treadle (on pull requests only) to speed up CI

Treadle will be used as the "defaultBackend" when the environment
variable CHISEL3_CI_USE_TREADLE is set. The intent is to set this
variable during CI for pre-merge CI (aka on pull requests).

The command line options for CIRCT's firtool command have been updated.

Previously, failed jobs in the CI matrix would cause the sentinel job
(all-tests-passed) to be skipped, which for purposes of Github Actions
branch protection would count as "success". This allowed PRs with
failing CI to be merged. This new approach which uses two sentinel jobs
should not suffer from this same issue.

This enables emission of modules that serialize to >2 GiB of .fir text.

* Cleanup Cookbook and printing docs
* Format specifiers are actually concise now

Co-authored-by: Megan Wachs <megan@sifive.com>

Referenced to: chipsalliance/chisel3#2728

Add macro for determining Chisel structural subtypes. This replaces the                                                                                                                                                       
use of built-in <:< for determining what types can be cast with
.viewAsSuperType.

Co-authored-by: Jack Koenig <koenig@sifive.com>