From 4c53361b205ad30acc05136388b789296a4180f7 Mon Sep 17 00:00:00 2001
From: Heejin Ahn <aheejin@gmail.com>
Date: Tue, 19 Dec 2023 11:10:27 -0800
Subject: [EH] Add instructions for new proposal (#6181)

This adds basic support for the new instructions in the new EH proposal
passed at the Oct CG hybrid CG meeting:
https://github.com/WebAssembly/meetings/blob/main/main/2023/CG-10.md
https://github.com/WebAssembly/exception-handling/blob/main/proposals/exception-handling/Exceptions.md

This mainly adds two instructions: `try_table` and `throw_ref`. This is
the bare minimum required to read and write text and binary format, and
does not include analyses or optimizations. (It includes some analysis
required for validation of existing instructions.) Validation for
the new instructions is not yet included.

`try_table` faces the same problem with the `resume` instruction in
 #6083 that without the module-level tag info, we are unable to know the
'sent types' of `try_table`. This solves it with a similar approach
taken in #6083: this adds `Module*` parameter to `finalize` methods,
which defaults to `nullptr` when not given. The `Module*` parameter is
given when called from the binary and text parser, and we cache those
tag types in `sentTypes` array within `TryTable` class. In later
optimization passes, as long as they don't touch tags, it is fine to
call `finalize` without the `Module*`. Refer to
https://github.com/WebAssembly/binaryen/pull/6083#issuecomment-1854634679
and #6096 for related discussions when `resume` was added.
---
 src/wasm/wasm.cpp | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

(limited to 'src/wasm/wasm.cpp')

diff --git a/src/wasm/wasm.cpp b/src/wasm/wasm.cpp
index 8ff2dc978..6589ca069 100644
--- a/src/wasm/wasm.cpp
+++ b/src/wasm/wasm.cpp
@@ -900,6 +900,47 @@ void Throw::finalize() { type = Type::unreachable; }
 
 void Rethrow::finalize() { type = Type::unreachable; }
 
+void ThrowRef::finalize() { type = Type::unreachable; }
+
+bool TryTable::hasCatchAll() const {
+  return std::any_of(
+    catchTags.begin(), catchTags.end(), [](Name t) { return !t; });
+}
+
+static void populateTryTableSentTypes(TryTable* curr, Module* wasm) {
+  if (!wasm) {
+    return;
+  }
+  curr->sentTypes.clear();
+  Type exnref = Type(HeapType::exn, Nullable);
+  for (Index i = 0; i < curr->catchTags.size(); i++) {
+    auto tagName = curr->catchTags[i];
+    std::vector<Type> sentType;
+    if (tagName) {
+      for (auto t : wasm->getTag(tagName)->sig.params) {
+        sentType.push_back(t);
+      }
+    }
+    if (curr->catchRefs[i]) {
+      sentType.push_back(exnref);
+    }
+    curr->sentTypes.push_back(sentType.empty() ? Type::none : Type(sentType));
+  }
+}
+
+void TryTable::finalize(Module* wasm) {
+  type = body->type;
+  populateTryTableSentTypes(this, wasm);
+}
+
+void TryTable::finalize(Type type_, Module* wasm) {
+  type = type_;
+  if (type == Type::none && body->type == Type::unreachable) {
+    type = Type::unreachable;
+  }
+  populateTryTableSentTypes(this, wasm);
+}
+
 void TupleMake::finalize() {
   std::vector<Type> types;
   types.reserve(operands.size());
-- 
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