optimizations: Implement transform::ShouldRun()
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>
diff --git a/src/transform/first_index_offset.cc b/src/transform/first_index_offset.cc
index 50a65fa..9719013 100644
--- a/src/transform/first_index_offset.cc
+++ b/src/transform/first_index_offset.cc
@@ -57,6 +57,15 @@
FirstIndexOffset::FirstIndexOffset() = default;
FirstIndexOffset::~FirstIndexOffset() = default;
+bool FirstIndexOffset::ShouldRun(const Program* program, const DataMap&) const {
+ for (auto* fn : program->AST().Functions()) {
+ if (fn->PipelineStage() == ast::PipelineStage::kVertex) {
+ return true;
+ }
+ }
+ return false;
+}
+
void FirstIndexOffset::Run(CloneContext& ctx,
const DataMap& inputs,
DataMap& outputs) const {
