Refactor interaction between Pass and PassRunner (#5093)

Previously only WalkerPasses had access to the `getPassRunner` and
`getPassOptions` methods. Move those methods to `Pass` so all passes can use
them. As a result, the `PassRunner` passed to `Pass::run` and
`Pass::runOnFunction` is no longer necessary, so remove it.

Also update `Pass::create` to return a unique_ptr, which is more efficient than
having it return a raw pointer only to have the `PassRunner` wrap that raw
pointer in a `unique_ptr`.

Delete the unused template `PassRunner::getLast()`, which looks like it was
intended to enable retrieving previous analyses and has been in the code base
since 2015 but is not implemented anywhere.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/ir/flat.h b/src/ir/flat.h
index 70a6beac7..1a8722726 100644
--- a/src/ir/flat.h
+++ b/src/ir/flat.h
@@ -118,7 +118,9 @@ inline void verifyFlatness(Module* module) {
 
     bool modifiesBinaryenIR() override { return false; }
 
-    VerifyFlatness* create() override { return new VerifyFlatness(); }
+    std::unique_ptr<Pass> create() override {
+      return std::make_unique<VerifyFlatness>();
+    }
 
     void doVisitFunction(Function* func) { verifyFlatness(func); }
   };