[EH] Replace event with tag (#3937)

We recently decided to change 'event' to 'tag', and to 'event section'
to 'tag section', out of the rationale that the section contains a
generalized tag that references a type, which may be used for something
other than exceptions, and the name 'event' can be confusing in the web
context.

See
- https://github.com/WebAssembly/exception-handling/issues/159#issuecomment-857910130
- https://github.com/WebAssembly/exception-handling/pull/161

2 files changed, 23 insertions, 25 deletions

diff --git a/src/tools/fuzzing.h b/src/tools/fuzzing.h
index 0635dc61d..f1fc61e06 100644
--- a/src/tools/fuzzing.h
+++ b/src/tools/fuzzing.h
@@ -200,7 +200,7 @@ public:
     setupTables();
     setupGlobals();
     if (wasm.features.hasExceptionHandling()) {
-      setupEvents();
+      setupTags();
     }
     modifyInitialFunctions();
     addImportLoggingSupport();
@@ -495,14 +495,13 @@ private:
     }
   }
 
-  void setupEvents() {
+  void setupTags() {
     Index num = upTo(3);
     for (size_t i = 0; i < num; i++) {
-      auto event =
-        builder.makeEvent(Names::getValidEventName(wasm, "event$"),
-                          WASM_EVENT_ATTRIBUTE_EXCEPTION,
-                          Signature(getControlFlowType(), Type::none));
-      wasm.addEvent(std::move(event));
+      auto tag = builder.makeTag(Names::getValidTagName(wasm, "tag$"),
+                                 WASM_TAG_ATTRIBUTE_EXCEPTION,
+                                 Signature(getControlFlowType(), Type::none));
+      wasm.addTag(std::move(tag));
     }
   }
 
diff --git a/src/tools/wasm-metadce.cpp b/src/tools/wasm-metadce.cpp
index a0890c8c4..29ac01f90 100644
--- a/src/tools/wasm-metadce.cpp
+++ b/src/tools/wasm-metadce.cpp
@@ -58,12 +58,12 @@ struct MetaDCEGraph {
   std::unordered_map<Name, Name> exportToDCENode;
   std::unordered_map<Name, Name> functionToDCENode; // function name => DCE name
   std::unordered_map<Name, Name> globalToDCENode;   // global name => DCE name
-  std::unordered_map<Name, Name> eventToDCENode;    // event name => DCE name
+  std::unordered_map<Name, Name> tagToDCENode;      // tag name => DCE name
 
   std::unordered_map<Name, Name> DCENodeToExport; // reverse maps
   std::unordered_map<Name, Name> DCENodeToFunction;
   std::unordered_map<Name, Name> DCENodeToGlobal;
-  std::unordered_map<Name, Name> DCENodeToEvent;
+  std::unordered_map<Name, Name> DCENodeToTag;
 
   // imports are not mapped 1:1 to DCE nodes in the wasm, since env.X might
   // be imported twice, for example. So we don't map a DCE node to an Import,
@@ -95,8 +95,8 @@ struct MetaDCEGraph {
     return getImportId(imp->module, imp->base);
   }
 
-  ImportId getEventImportId(Name name) {
-    auto* imp = wasm.getEvent(name);
+  ImportId getTagImportId(Name name) {
+    auto* imp = wasm.getTag(name);
     return getImportId(imp->module, imp->base);
   }
 
@@ -126,14 +126,14 @@ struct MetaDCEGraph {
       globalToDCENode[global->name] = dceName;
       nodes[dceName] = DCENode(dceName);
     });
-    ModuleUtils::iterDefinedEvents(wasm, [&](Event* event) {
-      auto dceName = getName("event", event->name.str);
-      DCENodeToEvent[dceName] = event->name;
-      eventToDCENode[event->name] = dceName;
+    ModuleUtils::iterDefinedTags(wasm, [&](Tag* tag) {
+      auto dceName = getName("tag", tag->name.str);
+      DCENodeToTag[dceName] = tag->name;
+      tagToDCENode[tag->name] = dceName;
       nodes[dceName] = DCENode(dceName);
     });
-    // only process function, global, and event imports - the table and memory
-    // are always there
+    // only process function, global, and tag imports - the table and memory are
+    // always there
     ModuleUtils::iterImportedFunctions(wasm, [&](Function* import) {
       auto id = getImportId(import->module, import->base);
       if (importIdToDCENode.find(id) == importIdToDCENode.end()) {
@@ -148,7 +148,7 @@ struct MetaDCEGraph {
         importIdToDCENode[id] = dceName;
       }
     });
-    ModuleUtils::iterImportedEvents(wasm, [&](Event* import) {
+    ModuleUtils::iterImportedTags(wasm, [&](Tag* import) {
       auto id = getImportId(import->module, import->base);
       if (importIdToDCENode.find(id) == importIdToDCENode.end()) {
         auto dceName = getName("importId", import->name.str);
@@ -178,12 +178,11 @@ struct MetaDCEGraph {
           node.reaches.push_back(
             importIdToDCENode[getGlobalImportId(exp->value)]);
         }
-      } else if (exp->kind == ExternalKind::Event) {
-        if (!wasm.getEvent(exp->value)->imported()) {
-          node.reaches.push_back(eventToDCENode[exp->value]);
+      } else if (exp->kind == ExternalKind::Tag) {
+        if (!wasm.getTag(exp->value)->imported()) {
+          node.reaches.push_back(tagToDCENode[exp->value]);
         } else {
-          node.reaches.push_back(
-            importIdToDCENode[getEventImportId(exp->value)]);
+          node.reaches.push_back(importIdToDCENode[getTagImportId(exp->value)]);
         }
       }
     }
@@ -394,8 +393,8 @@ public:
       if (DCENodeToGlobal.find(name) != DCENodeToGlobal.end()) {
         std::cout << "  is global " << DCENodeToGlobal[name] << '\n';
       }
-      if (DCENodeToEvent.find(name) != DCENodeToEvent.end()) {
-        std::cout << "  is event " << DCENodeToEvent[name] << '\n';
+      if (DCENodeToTag.find(name) != DCENodeToTag.end()) {
+        std::cout << "  is tag " << DCENodeToTag[name] << '\n';
       }
       for (auto target : node.reaches) {
         std::cout << "  reaches: " << target.str << '\n';