Print the features section in a comment (#3563)

2 files changed, 19 insertions, 0 deletions

diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 9b59de444..a10467018 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -3240,6 +3240,10 @@ struct PrintSExpression : public OverriddenVisitor<PrintSExpression> {
       }
       o << maybeNewLine;
     }
+    if (curr->hasFeaturesSection) {
+      doIndent(o, indent);
+      o << ";; features section: " << curr->features.toString() << '\n';
+    }
     decIndent();
     o << maybeNewLine;
     currModule = nullptr;
diff --git a/src/wasm-features.h b/src/wasm-features.h
index d2e3f343f..237dc7757 100644
--- a/src/wasm-features.h
+++ b/src/wasm-features.h
@@ -75,6 +75,21 @@ struct FeatureSet {
     }
   }
 
+  std::string toString() {
+    std::string ret;
+    uint32_t x = 1;
+    while (x & Feature::All) {
+      if (features & x) {
+        if (!ret.empty()) {
+          ret += ", ";
+        }
+        ret += toString(Feature(x));
+      }
+      x <<= 1;
+    }
+    return ret;
+  }
+
   FeatureSet() : features(MVP) {}
   FeatureSet(uint32_t features) : features(features) {}
   operator uint32_t() const { return features; }