Add contains() to custom containers and use where possible. NFC

This matches the C++20 API that we cannot quite use yet.  At least not
until #8218 lands.

Author: sbc100

src/passes/DeadArgumentElimination2.cpp

@@ -1496,7 +1496,7 @@ void DAE2::collectStats() {
       if (auto* loc = std::get_if<FuncParamLoc>(&node)) {
         auto [funcIndex, paramIndex] = *loc;
         for (auto loc : parent.funcInfos[funcIndex].callerParams[paramIndex]) {
-          if (optimizedNodes.count(loc)) {
+          if (optimizedNodes.contains(loc)) {
             push(loc);
           }
         }
@@ -1505,7 +1505,7 @@ void DAE2::collectStats() {
         if (auto it = parent.typeTreeInfos.find(funcType);
             it != parent.typeTreeInfos.end()) {
           for (auto loc : it->second.callerParams[paramIndex]) {
-            if (optimizedNodes.count(loc)) {
+            if (optimizedNodes.contains(loc)) {
               push(loc);
             }
           }

src/passes/TypeMerging.cpp

@@ -396,7 +396,7 @@ bool TypeMerging::merge(MergeKind kind) {
           super &&
           std::any_of(chain.begin(), chain.end(), [&](HeapType t) -> bool {
             auto super = t.getDeclaredSuperType();
-            return super && exactCastTypes.count(*super);
+            return super && exactCastTypes.contains(*super);
           });
         if (!super || !shapeEq(type, *super) || superHasExactCast) {
           // Create a new partition for this type and bail.

src/support/insert_ordered.h

@@ -74,6 +74,7 @@ template<typename T> struct InsertOrderedSet {
   }
 
   size_t count(const T& val) const { return Map.count(val); }
+  bool contains(const T& val) const { return Map.find(val) != Map.end(); }
 
   InsertOrderedSet() = default;
   InsertOrderedSet(const InsertOrderedSet& other) { *this = other; }
@@ -160,6 +161,7 @@ template<typename Key, typename T> struct InsertOrderedMap {
   size_t size() const { return Map.size(); }
   bool empty() const { return Map.empty(); }
   size_t count(const Key& k) const { return Map.count(k); }
+  bool contains(const Key& k) const { return Map.find(k) != Map.end(); }
 
   InsertOrderedMap() = default;
   InsertOrderedMap(const InsertOrderedMap& other) {

src/support/small_set.h

@@ -185,17 +185,19 @@ class SmallSetBase {
     }
   }
 
-  size_t count(const T& x) const {
+  size_t count(const T& x) const { return contains(x) ? 1 : 0; }
+
+  bool contains(const T& x) const {
     if (usingFixed()) {
       // Do a linear search.
       for (size_t i = 0; i < fixed.used; i++) {
         if (fixed.storage[i] == x) {
-          return 1;
+          return true;
         }
       }
-      return 0;
+      return false;
     } else {
-      return flexible.count(x);
+      return flexible.find(x) != flexible.end();
     }
   }
 

src/wasm/parsing.cpp

@@ -115,7 +115,7 @@ struct DuplicateNameScanner
       // TODO: This could be done in a single insert operation that checks
       //       whether we actually inserted, if we improved
       //       SmallSetBase::insert to return a value like std::set does.
-      if (seen.count(name)) {
+      if (seen.contains(name)) {
         // A name has been defined more than once; we'll need to fix that.
         ok = false;
       } else {