Add exception handling feature (#2083)

This only adds the feature and its flag and not the instructions yet.

Author: aheejin

src/tools/tool-options.h

@@ -68,6 +68,8 @@ struct ToolOptions : public Options {
       .addFeature(FeatureSet::TruncSat, "nontrapping float-to-int operations")
       .addFeature(FeatureSet::SIMD, "SIMD operations and types")
       .addFeature(FeatureSet::BulkMemory, "bulk memory operations")
+      .addFeature(FeatureSet::ExceptionHandling,
+                  "exception handling operations")
       .add("--no-validation",
            "-n",
            "Disables validation, assumes inputs are correct",

src/wasm-binary.h

@@ -399,6 +399,7 @@ extern const char* ExceptionHandlingFeature;
 extern const char* TruncSatFeature;
 extern const char* SignExtFeature;
 extern const char* SIMD128Feature;
+extern const char* ExceptionHandlingFeature;
 
 enum Subsection {
   NameFunction = 1,

src/wasm-features.h

@@ -31,7 +31,9 @@ struct FeatureSet {
     SIMD = 1 << 3,
     BulkMemory = 1 << 4,
     SignExt = 1 << 5,
-    All = Atomics | MutableGlobals | TruncSat | SIMD | BulkMemory | SignExt
+    ExceptionHandling = 1 << 6,
+    All = Atomics | MutableGlobals | TruncSat | SIMD | BulkMemory | SignExt |
+          ExceptionHandling
   };
 
   static std::string toString(Feature f) {
@@ -48,6 +50,8 @@ struct FeatureSet {
         return "bulk-memory";
       case SignExt:
         return "sign-ext";
+      case ExceptionHandling:
+        return "exception-handling";
       default:
         WASM_UNREACHABLE();
     }
@@ -64,6 +68,7 @@ struct FeatureSet {
   bool hasSIMD() const { return features & SIMD; }
   bool hasBulkMemory() const { return features & BulkMemory; }
   bool hasSignExt() const { return features & SignExt; }
+  bool hasExceptionHandling() const { return features & ExceptionHandling; }
   bool hasAll() const { return features & All; }
 
   void makeMVP() { features = MVP; }
@@ -76,6 +81,7 @@ struct FeatureSet {
   void setSIMD(bool v = true) { set(SIMD, v); }
   void setBulkMemory(bool v = true) { set(BulkMemory, v); }
   void setSignExt(bool v = true) { set(SignExt, v); }
+  void setExceptionHandling(bool v = true) { set(ExceptionHandling, v); }
   void setAll(bool v = true) { features = v ? All : MVP; }
 
   void enable(const FeatureSet& other) { features |= other.features; }
@@ -90,6 +96,9 @@ struct FeatureSet {
     if (hasBulkMemory()) {
       f(BulkMemory);
     }
+    if (hasExceptionHandling()) {
+      f(ExceptionHandling);
+    }
     if (hasMutableGlobals()) {
       f(MutableGlobals);
     }

src/wasm/wasm-binary.cpp

@@ -647,6 +647,8 @@ void WasmBinaryWriter::writeFeaturesSection() {
         return "bulk-memory";
       case FeatureSet::SignExt:
         return "sign-ext";
+      case FeatureSet::ExceptionHandling:
+        return "exception-handling";
       default:
         WASM_UNREACHABLE();
     }
@@ -2079,7 +2081,7 @@ void WasmBinaryBuilder::readFeatures(size_t payloadLen) {
     } else if (name == BinaryConsts::UserSections::BulkMemoryFeature) {
       wasm.features.setBulkMemory();
     } else if (name == BinaryConsts::UserSections::ExceptionHandlingFeature) {
-      WASM_UNREACHABLE(); // TODO: exception handling
+      wasm.features.setExceptionHandling();
     } else if (name == BinaryConsts::UserSections::TruncSatFeature) {
       wasm.features.setTruncSat();
     } else if (name == BinaryConsts::UserSections::SignExtFeature) {

test/unit/test_features.py

@@ -24,6 +24,9 @@ def check_sign_ext(self, module, error):
   def check_bulk_mem(self, module, error):
     self.check_feature(module, error, '--enable-bulk-memory')
 
+  def check_exception_handling(self, module, error):
+    self.check_feature(module, error, '--enable-exception-handling')
+
   def test_v128_signature(self):
     module = '''
     (module