4 files changed, 78 insertions, 3 deletions

diff --git a/src/binaryen-c.cpp b/src/binaryen-c.cpp
index be06cce83..03c6912f0 100644
--- a/src/binaryen-c.cpp
+++ b/src/binaryen-c.cpp
@@ -367,6 +367,30 @@ BinaryenExternalKind BinaryenExternalGlobal(void) {
   return static_cast<BinaryenExternalKind>(ExternalKind::Global);
 }
 
+// Features
+
+BinaryenFeatures BinaryenFeatureAtomics(void) {
+  return static_cast<BinaryenFeatures>(FeatureSet::Feature::Atomics);
+}
+BinaryenFeatures BinaryenFeatureBulkMemory(void) {
+  return static_cast<BinaryenFeatures>(FeatureSet::Feature::BulkMemory);
+}
+BinaryenFeatures BinaryenFeatureMutableGlobals(void) {
+  return static_cast<BinaryenFeatures>(FeatureSet::Feature::MutableGlobals);
+}
+BinaryenFeatures BinaryenFeatureNontrappingFPToInt(void) {
+  return static_cast<BinaryenFeatures>(FeatureSet::Feature::TruncSat);
+}
+BinaryenFeatures BinaryenFeatureSignExt(void) {
+  return static_cast<BinaryenFeatures>(FeatureSet::Feature::SignExt);
+}
+BinaryenFeatures BinaryenFeatureSIMD128(void) {
+  return static_cast<BinaryenFeatures>(FeatureSet::Feature::SIMD);
+}
+BinaryenFeatures BinaryenFeatureExceptionHandling(void) {
+  return static_cast<BinaryenFeatures>(FeatureSet::Feature::ExceptionHandling);
+}
+
 // Modules
 
 BinaryenModuleRef BinaryenModuleCreate(void) {
@@ -3053,6 +3077,24 @@ void BinaryenSetStart(BinaryenModuleRef module, BinaryenFunctionRef start) {
   wasm->addStart(((Function*)start)->name);
 }
 
+// Features
+
+BinaryenFeatures BinaryenGetFeatures(BinaryenModuleRef module) {
+  if (tracing) {
+    std::cout << "  BinaryenGetFeatures(the_module);\n";
+  }
+  auto* wasm = static_cast<Module*>(module);
+  return wasm->features.features;
+}
+
+void BinaryenSetFeatures(BinaryenModuleRef module, BinaryenFeatures features) {
+  if (tracing) {
+    std::cout << "  BinaryenSetFeatures(the_module, " << features << ");\n";
+  }
+  auto* wasm = static_cast<Module*>(module);
+  wasm->features.features = features;
+}
+
 //
 // ========== Module Operations ==========
 //
@@ -3106,8 +3148,6 @@ int BinaryenModuleValidate(BinaryenModuleRef module) {
   }
 
   Module* wasm = (Module*)module;
-  // TODO(tlively): Add C API for managing features
-  wasm->features = FeatureSet::All;
   return WasmValidator().validate(*wasm) ? 1 : 0;
 }
 
diff --git a/src/binaryen-c.h b/src/binaryen-c.h
index 820b23cca..19434692b 100644
--- a/src/binaryen-c.h
+++ b/src/binaryen-c.h
@@ -137,6 +137,19 @@ BinaryenExternalKind BinaryenExternalTable(void);
 BinaryenExternalKind BinaryenExternalMemory(void);
 BinaryenExternalKind BinaryenExternalGlobal(void);
 
+// Features. Call to get the value of each; you can cache them. Use bitwise
+// operators to combine and test particular features.
+
+typedef uint32_t BinaryenFeatures;
+
+BinaryenFeatures BinaryenFeatureAtomics(void);
+BinaryenFeatures BinaryenFeatureBulkMemory(void);
+BinaryenFeatures BinaryenFeatureMutableGlobals(void);
+BinaryenFeatures BinaryenFeatureNontrappingFPToInt(void);
+BinaryenFeatures BinaryenFeatureSignExt(void);
+BinaryenFeatures BinaryenFeatureSIMD128(void);
+BinaryenFeatures BinaryenFeatureExceptionHandling(void);
+
 // Modules
 //
 // Modules contain lists of functions, imports, exports, function types. The
@@ -929,6 +942,12 @@ void BinaryenSetMemory(BinaryenModuleRef module,
 
 void BinaryenSetStart(BinaryenModuleRef module, BinaryenFunctionRef start);
 
+// Features
+
+// These control what features are allowed when validation and in passes.
+BinaryenFeatures BinaryenGetFeatures(BinaryenModuleRef module);
+void BinaryenSetFeatures(BinaryenModuleRef module, BinaryenFeatures features);
+
 //
 // ========== Module Operations ==========
 //
diff --git a/src/js/binaryen.js-post.js b/src/js/binaryen.js-post.js
index 8aa28a08c..fe0594b91 100644
--- a/src/js/binaryen.js-post.js
+++ b/src/js/binaryen.js-post.js
@@ -85,6 +85,17 @@ Module['ExternalTable'] = Module['_BinaryenExternalTable']();
 Module['ExternalMemory'] = Module['_BinaryenExternalMemory']();
 Module['ExternalGlobal'] = Module['_BinaryenExternalGlobal']();
 
+// Features
+Module['Features'] = {
+  'Atomics': Module['_BinaryenFeatureAtomics'](),
+  'BulkMemory': Module['_BinaryenFeatureBulkMemory'](),
+  'MutableGlobals': Module['_BinaryenFeatureMutableGlobals'](),
+  'NontrappingFPToInt': Module['_BinaryenFeatureNontrappingFPToInt'](),
+  'SignExt': Module['_BinaryenFeatureSignExt'](),
+  'SIMD128': Module['_BinaryenFeatureSIMD128'](),
+  'ExceptionHandling': Module['_BinaryenFeatureExceptionHandling'](),
+};
+
 // Operations
 Module['ClzInt32'] = Module['_BinaryenClzInt32']();
 Module['CtzInt32'] = Module['_BinaryenCtzInt32']();
@@ -1866,6 +1877,12 @@ function wrapModule(module, self) {
   self['setStart'] = function(start) {
     return Module['_BinaryenSetStart'](module, start);
   };
+  self['getFeatures'] = function() {
+    return Module['_BinaryenGetFeatures'](module);
+  };
+  self['setFeatures'] = function(features) {
+    Module['_BinaryenSetFeatures'](module, features);
+  };
   self['emitText'] = function() {
     var old = out;
     var ret = '';
diff --git a/src/wasm-features.h b/src/wasm-features.h
index 340ca86ae..325f413a1 100644
--- a/src/wasm-features.h
+++ b/src/wasm-features.h
@@ -128,7 +128,6 @@ struct FeatureSet {
     return *this;
   }
 
-private:
   uint32_t features;
 };