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, 2 insertions, 2 deletions

diff --git a/src/ir/hashed.h b/src/ir/hashed.h
index 060fea453..4e90951f5 100644
--- a/src/ir/hashed.h
+++ b/src/ir/hashed.h
@@ -38,8 +38,8 @@ struct FunctionHasher : public WalkerPass<PostWalker<FunctionHasher>> {
   FunctionHasher(Map* output)
     : output(output), customHasher(ExpressionAnalyzer::nothingHasher) {}
 
-  FunctionHasher* create() override {
-    return new FunctionHasher(output, customHasher);
+  std::unique_ptr<Pass> create() override {
+    return std::make_unique<FunctionHasher>(output, customHasher);
   }
 
   static Map createMap(Module* module) {