[llvm] [CodeGen] Port WasmEHPrepare to new pass manager (PR #74435)

[Heejin Ahn via llvm-commits]

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@@ -88,10 +89,12 @@
 
 using namespace llvm;
 
-#define DEBUG_TYPE "wasmehprepare"
+#define DEBUG_TYPE "wasm-eh-prepare"
 
 namespace {
-class WasmEHPrepare : public FunctionPass {
+class WasmEHPrepareImpl {
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aheejin wrote:

I'm not familiar with the new pass manager. Does this additional `Impl` class necessary for the new pass manager? If there is a guide to port passes to the new pass manager, can you point it out? (I searched a little but didn't find much other than https://llvm.org/docs/NewPassManager.html)

https://github.com/llvm/llvm-project/pull/74435