Add const specifiers (#1952)

With this we can write stuff like:

const wasm::Expression* p;
const wasm::Binary* q = p->cast<wasm::Binary>();

2 files changed, 15 insertions, 4 deletions

diff --git a/src/parsing.h b/src/parsing.h
index 6eecb38f2..97fc88432 100644
--- a/src/parsing.h
+++ b/src/parsing.h
@@ -40,7 +40,7 @@ struct ParseException {
   ParseException(std::string text) : text(text), line(-1), col(-1) {}
   ParseException(std::string text, size_t line, size_t col) : text(text), line(line), col(col) {}
 
-  void dump(std::ostream& o) {
+  void dump(std::ostream& o) const {
     Colors::magenta(o);
     o << "[";
     Colors::red(o);
@@ -63,7 +63,7 @@ struct MapParseException {
   MapParseException() : text("unknown parse error") {}
   MapParseException(std::string text) : text(text) {}
 
-  void dump(std::ostream& o) {
+  void dump(std::ostream& o) const {
     Colors::magenta(o);
     o << "[";
     Colors::red(o);
diff --git a/src/wasm.h b/src/wasm.h
index a4fb7e357..258ed0f35 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -54,7 +54,7 @@ struct FeatureSet {
   FeatureSet(uint32_t features) : features(features) {}
 
   bool isMVP() const { return features == MVP; }
-  bool has(Feature f) { return (features & f) == f; }
+  bool has(Feature f) const { return (features & f) == f; }
   bool hasAtomics() const { return features & Atomics; }
   bool hasMutableGlobals() const { return features & MutableGlobals; }
   bool hasTruncSat() const { return features & TruncSat; }
@@ -270,7 +270,7 @@ public:
   void finalize() {}
 
   template<class T>
-  bool is() {
+  bool is() const {
     return int(_id) == int(T::SpecificId);
   }
 
@@ -279,11 +279,22 @@ public:
     return int(_id) == int(T::SpecificId) ? (T*)this : nullptr;
   }
 
+  template <class T>
+  const T* dynCast() const {
+    return int(_id) == int(T::SpecificId) ? (const T*)this : nullptr;
+  }
+
   template<class T>
   T* cast() {
     assert(int(_id) == int(T::SpecificId));
     return (T*)this;
   }
+
+  template<class T>
+  const T* cast() const {
+    assert(int(_id) == int(T::SpecificId));
+    return (const T*)this;
+  }
 };
 
 const char* getExpressionName(Expression* curr);