Followups to #2292, code cleanups for opt-utils.h (#2293)

Author: kripken

src/passes/opt-utils.h

@@ -17,6 +17,7 @@
 #ifndef wasm_passes_opt_utils_h
 #define wasm_passes_opt_utils_h
 
+#include <functional>
 #include <unordered_set>
 
 #include <pass.h>
@@ -56,51 +57,44 @@ inline void optimizeAfterInlining(std::unordered_set<Function*>& funcs,
 struct CallTargetReplacer : public WalkerPass<PostWalker<CallTargetReplacer>> {
   bool isFunctionParallel() override { return true; }
 
-  CallTargetReplacer(std::map<Name, Name>* replacements)
-    : replacements(replacements) {}
+  using MaybeReplace = std::function<void(Name&)>;
+
+  CallTargetReplacer(MaybeReplace maybeReplace) : maybeReplace(maybeReplace) {}
 
   CallTargetReplacer* create() override {
-    return new CallTargetReplacer(replacements);
+    return new CallTargetReplacer(maybeReplace);
   }
 
-  void visitCall(Call* curr) {
-    auto iter = replacements->find(curr->target);
-    if (iter != replacements->end()) {
-      curr->target = iter->second;
-    }
-  }
+  void visitCall(Call* curr) { maybeReplace(curr->target); }
 
 private:
-  std::map<Name, Name>* replacements;
+  MaybeReplace maybeReplace;
 };
 
 inline void replaceFunctions(PassRunner* runner,
                              Module& module,
-                             std::map<Name, Name>& replacements) {
+                             const std::map<Name, Name>& replacements) {
+  auto maybeReplace = [&](Name& name) {
+    auto iter = replacements.find(name);
+    if (iter != replacements.end()) {
+      name = iter->second;
+    }
+  };
   // replace direct calls
-  CallTargetReplacer(&replacements).run(runner, &module);
+  CallTargetReplacer(maybeReplace).run(runner, &module);
   // replace in table
   for (auto& segment : module.table.segments) {
     for (auto& name : segment.data) {
-      auto iter = replacements.find(name);
-      if (iter != replacements.end()) {
-        name = iter->second;
-      }
+      maybeReplace(name);
     }
   }
   // replace in start
   if (module.start.is()) {
-    auto iter = replacements.find(module.start);
-    if (iter != replacements.end()) {
-      module.start = iter->second;
-    }
+    maybeReplace(module.start);
   }
   // replace in exports
   for (auto& exp : module.exports) {
-    auto iter = replacements.find(exp->value);
-    if (iter != replacements.end()) {
-      exp->value = iter->second;
-    }
+    maybeReplace(exp->value);
   }
 }