5 files changed, 86 insertions, 3 deletions

diff --git a/src/ir/ReFinalize.cpp b/src/ir/ReFinalize.cpp
index 0f78d37b7..c32d6efbf 100644
--- a/src/ir/ReFinalize.cpp
+++ b/src/ir/ReFinalize.cpp
@@ -128,7 +128,12 @@ void ReFinalize::visitTableFill(TableFill* curr) { curr->finalize(); }
 void ReFinalize::visitTableCopy(TableCopy* curr) { curr->finalize(); }
 void ReFinalize::visitTableInit(TableInit* curr) { curr->finalize(); }
 void ReFinalize::visitTry(Try* curr) { curr->finalize(); }
-void ReFinalize::visitTryTable(TryTable* curr) { curr->finalize(); }
+void ReFinalize::visitTryTable(TryTable* curr) {
+  curr->finalize();
+  for (size_t i = 0; i < curr->catchDests.size(); i++) {
+    updateBreakValueType(curr->catchDests[i], curr->sentTypes[i]);
+  }
+}
 void ReFinalize::visitThrow(Throw* curr) { curr->finalize(); }
 void ReFinalize::visitRethrow(Rethrow* curr) { curr->finalize(); }
 void ReFinalize::visitThrowRef(ThrowRef* curr) { curr->finalize(); }
diff --git a/src/ir/effects.h b/src/ir/effects.h
index fee8b3441..716624d64 100644
--- a/src/ir/effects.h
+++ b/src/ir/effects.h
@@ -431,6 +431,14 @@ private:
         self->pushTask(doStartTry, currp);
         return;
       }
+      if (auto* tryTable = curr->dynCast<TryTable>()) {
+        // We need to increment try depth before starting.
+        self->pushTask(doEndTryTable, currp);
+        self->pushTask(doVisitTryTable, currp);
+        self->pushTask(scan, &tryTable->body);
+        self->pushTask(doStartTryTable, currp);
+        return;
+      }
       PostWalker<InternalAnalyzer, OverriddenVisitor<InternalAnalyzer>>::scan(
         self, currp);
     }
@@ -472,6 +480,24 @@ private:
       self->parent.catchDepth--;
     }
 
+    static void doStartTryTable(InternalAnalyzer* self, Expression** currp) {
+      auto* curr = (*currp)->cast<TryTable>();
+      // We only count 'try_table's with a 'catch_all' because instructions
+      // within a 'try_table' without a 'catch_all' can still throw outside of
+      // the try.
+      if (curr->hasCatchAll()) {
+        self->parent.tryDepth++;
+      }
+    }
+
+    static void doEndTryTable(InternalAnalyzer* self, Expression** currp) {
+      auto* curr = (*currp)->cast<TryTable>();
+      if (curr->hasCatchAll()) {
+        assert(self->parent.tryDepth > 0 && "try depth cannot be negative");
+        self->parent.tryDepth--;
+      }
+    }
+
     void visitBlock(Block* curr) {
       if (curr->name.is()) {
         parent.breakTargets.erase(curr->name); // these were internal breaks
diff --git a/src/ir/linear-execution.h b/src/ir/linear-execution.h
index c6593bd64..e8b1923aa 100644
--- a/src/ir/linear-execution.h
+++ b/src/ir/linear-execution.h
@@ -171,6 +171,12 @@ struct LinearExecutionWalker : public PostWalker<SubType, VisitorType> {
         self->pushTask(SubType::scan, &curr->cast<Try>()->body);
         break;
       }
+      case Expression::Id::TryTableId: {
+        self->pushTask(SubType::doVisitTryTable, currp);
+        self->pushTask(SubType::doNoteNonLinear, currp);
+        self->pushTask(SubType::scan, &curr->cast<TryTable>()->body);
+        break;
+      }
       case Expression::Id::ThrowId: {
         self->pushTask(SubType::doVisitThrow, currp);
         self->pushTask(SubType::doNoteNonLinear, currp);
diff --git a/src/ir/possible-contents.cpp b/src/ir/possible-contents.cpp
index e7454c7c6..e5e6cf659 100644
--- a/src/ir/possible-contents.cpp
+++ b/src/ir/possible-contents.cpp
@@ -1135,8 +1135,38 @@ struct InfoCollector
     }
   }
   void visitTryTable(TryTable* curr) {
-    // TODO: optimize when possible
-    addRoot(curr);
+    receiveChildValue(curr->body, curr);
+
+    // Connect caught tags with their branch targets, and materialize non-null
+    // exnref values.
+    auto numTags = curr->catchTags.size();
+    for (Index tagIndex = 0; tagIndex < numTags; tagIndex++) {
+      auto tag = curr->catchTags[tagIndex];
+      auto target = curr->catchDests[tagIndex];
+
+      Index exnrefIndex = 0;
+      if (tag.is()) {
+        auto params = getModule()->getTag(tag)->sig.params;
+
+        for (Index i = 0; i < params.size(); i++) {
+          if (isRelevant(params[i])) {
+            info.links.push_back(
+              {TagLocation{tag, i},
+               BreakTargetLocation{getFunction(), target, i}});
+          }
+        }
+
+        exnrefIndex = params.size();
+      }
+
+      if (curr->catchRefs[tagIndex]) {
+        auto location = CaughtExnRefLocation{};
+        addRoot(location,
+                PossibleContents::fromType(Type(HeapType::exn, NonNullable)));
+        info.links.push_back(
+          {location, BreakTargetLocation{getFunction(), target, exnrefIndex}});
+      }
+    }
   }
   void visitThrow(Throw* curr) {
     auto& operands = curr->operands;
diff --git a/src/ir/possible-contents.h b/src/ir/possible-contents.h
index 5ec4f758f..7b88483cf 100644
--- a/src/ir/possible-contents.h
+++ b/src/ir/possible-contents.h
@@ -473,6 +473,15 @@ struct TagLocation {
   }
 };
 
+// The location of an exnref materialized by a catch_ref or catch_all_ref clause
+// of a try_table. No data is stored here. exnrefs contain a tag and a payload
+// at run-time, as well as potential metadata such as stack traces, but we don't
+// track that. So this is the same as NullLocation in a way: we just need *a*
+// source of contents for places that receive an exnref.
+struct CaughtExnRefLocation {
+  bool operator==(const CaughtExnRefLocation& other) const { return true; }
+};
+
 // A null value. This is used as the location of the default value of a var in a
 // function, a null written to a struct field in struct.new_with_default, etc.
 struct NullLocation {
@@ -520,6 +529,7 @@ using Location = std::variant<ExpressionLocation,
                               SignatureResultLocation,
                               DataLocation,
                               TagLocation,
+                              CaughtExnRefLocation,
                               NullLocation,
                               ConeReadLocation>;
 
@@ -608,6 +618,12 @@ template<> struct hash<wasm::TagLocation> {
   }
 };
 
+template<> struct hash<wasm::CaughtExnRefLocation> {
+  size_t operator()(const wasm::CaughtExnRefLocation& loc) const {
+    return std::hash<const char*>()("caught-exnref-location");
+  }
+};
+
 template<> struct hash<wasm::NullLocation> {
   size_t operator()(const wasm::NullLocation& loc) const {
     return std::hash<wasm::Type>{}(loc.type);