Add runOnModuleCode helper. NFC (#4234)

This method is in parallel to runOnFunction above it. It sets the runner
and then does the walk, like that method.

Also set runner to nullptr by default. I noticed ubsan was warning on
things here, which this should avoid, but otherwise I'm not aware of an
actual bug, so this should be NFC. But it does provide a safer API
that should avoid future bugs.

5 files changed, 11 insertions, 5 deletions

diff --git a/src/pass.h b/src/pass.h
index 2bb34aeea..cc63971fe 100644
--- a/src/pass.h
+++ b/src/pass.h
@@ -391,7 +391,7 @@ protected:
 //
 template<typename WalkerType>
 class WalkerPass : public Pass, public WalkerType {
-  PassRunner* runner;
+  PassRunner* runner = nullptr;
 
 protected:
   typedef WalkerPass<WalkerType> super;
@@ -421,6 +421,12 @@ public:
     WalkerType::walkFunction(func);
   }
 
+  void runOnModuleCode(PassRunner* runner, Module* module) {
+    setPassRunner(runner);
+    WalkerType::setModule(module);
+    WalkerType::walkModuleCode(module);
+  }
+
   PassRunner* getPassRunner() { return runner; }
 
   PassOptions& getPassOptions() { return runner->options; }
diff --git a/src/passes/ConstantFieldPropagation.cpp b/src/passes/ConstantFieldPropagation.cpp
index 0894a822a..2fdd8333c 100644
--- a/src/passes/ConstantFieldPropagation.cpp
+++ b/src/passes/ConstantFieldPropagation.cpp
@@ -274,7 +274,7 @@ struct ConstantFieldPropagation : public Pass {
       functionSetInfos(*module);
     PCVScanner scanner(functionNewInfos, functionSetInfos);
     scanner.run(runner, module);
-    scanner.walkModuleCode(module);
+    scanner.runOnModuleCode(runner, module);
 
     // Combine the data from the functions.
     PCVStructValuesMap combinedNewInfos, combinedSetInfos;
diff --git a/src/passes/GlobalTypeOptimization.cpp b/src/passes/GlobalTypeOptimization.cpp
index 89d5b8c0a..35b10bfff 100644
--- a/src/passes/GlobalTypeOptimization.cpp
+++ b/src/passes/GlobalTypeOptimization.cpp
@@ -93,7 +93,7 @@ struct GlobalTypeOptimization : public Pass {
       functionSetInfos(*module);
     FieldInfoScanner scanner(functionNewInfos, functionSetInfos);
     scanner.run(runner, module);
-    scanner.walkModuleCode(module);
+    scanner.runOnModuleCode(runner, module);
 
     // Combine the data from the functions.
     StructValuesMap<FieldInfo> combinedNewInfos, combinedSetInfos;
diff --git a/src/passes/LegalizeJSInterface.cpp b/src/passes/LegalizeJSInterface.cpp
index e7a5f9220..e5a69beb1 100644
--- a/src/passes/LegalizeJSInterface.cpp
+++ b/src/passes/LegalizeJSInterface.cpp
@@ -143,7 +143,7 @@ struct LegalizeJSInterface : public Pass {
 
       Fixer fixer(&illegalImportsToLegal);
       fixer.run(runner, module);
-      fixer.walkModuleCode(module);
+      fixer.runOnModuleCode(runner, module);
 
       // Finally we can remove all the now-unused illegal imports
       for (const auto& pair : illegalImportsToLegal) {
diff --git a/src/passes/opt-utils.h b/src/passes/opt-utils.h
index 326f75f95..28ace047a 100644
--- a/src/passes/opt-utils.h
+++ b/src/passes/opt-utils.h
@@ -88,7 +88,7 @@ inline void replaceFunctions(PassRunner* runner,
   // replace direct calls in code both functions and module elements
   FunctionRefReplacer replacer(maybeReplace);
   replacer.run(runner, &module);
-  replacer.walkModuleCode(&module);
+  replacer.runOnModuleCode(runner, &module);
 
   // replace in start
   if (module.start.is()) {