This change adds an override for Transform::ShouldRun() for many of the transforms that can trivially detect whether running would be a no-op or not. Most programs do not require all the transforms to be run, and by skipping those that are not needed, significant performance wins can be had.
This change also removes Transform::Requires() and Program::HasTransformApplied(). This makes little sense now that transforms can be skipped, and the usefulness of this information has been severely reduced since the introduction of transforms that need to be run more than once.
Instread, just document on the transform class what the expectations are.
Issue: tint:1383
Change-Id: I1a6f27cc4ba61ca1475a4ba912c465db619f76c7
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/77121
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Transforms are supposed to be immutable, operating on the DataMaps provided for input and output, so make the methods const.
Add a ShouldRun() method which the Manager can use to skip over transforms that do not need to be run.
Change-Id: I320ac964577e94ac988748d8aca85bd43ee8d3b5
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/77120
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Migrate some of the validation logic over to use the results of behavior
analysis.
The most significant changes are:
* Unreachable-statements now consider merge-points of control flow. For
example, if all branches of a if-statement or switch-statement either
return or discard, the next statement will be considered unreachable.
* Unreachable statements are no longer an error, but a warning. See
https://github.com/gpuweb/gpuweb/issues/2378.
* Statements that follow a loops that does not break, or have a
conditional will now be considered unreachable.
* Unreachable statements produced by the SPIR-V reader are now removed
using the new RemoveUnreachableStatements transform.
Some other new changes include additional validation for the continuing
block for for-loops, to match the rules of a loop continuing block.
The new cases this validation is testing for are not expressible in
WGSL, but some transforms may produce complex continuing statements that
might violate these rules. All the writers are able to decay these
complex for-loop continuing statements to regular loops.
Bug: tint:1302
Change-Id: I0d8a48c73d5d5c30a1cddf92cc3383a692a58e61
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/71500
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: David Neto <dneto@google.com>
