3 files changed, 40 insertions, 42 deletions

diff --git a/src/ir/possible-constant.h b/src/ir/possible-constant.h
index 24f236a3c..c75669dab 100644
--- a/src/ir/possible-constant.h
+++ b/src/ir/possible-constant.h
@@ -19,6 +19,7 @@
 
 #include <variant>
 
+#include "ir/properties.h"
 #include "wasm-builder.h"
 #include "wasm.h"
 
@@ -47,9 +48,29 @@ private:
 public:
   PossibleConstantValues() : value(None()) {}
 
-  // Note a written value as we see it, and update our internal knowledge based
-  // on it and all previous values noted. This can be called using either a
-  // Literal or a Name, so it uses a template.
+  // Notes the contents of an expression and update our internal knowledge based
+  // on it and all previous values noted.
+  void note(Expression* expr, Module& wasm) {
+    // If this is a constant literal value, note that.
+    if (Properties::isConstantExpression(expr)) {
+      note(Properties::getLiteral(expr));
+      return;
+    }
+
+    // If this is an immutable global that we get, note that.
+    if (auto* get = expr->dynCast<GlobalGet>()) {
+      auto* global = wasm.getGlobal(get->name);
+      if (global->mutable_ == Immutable) {
+        note(get->name);
+        return;
+      }
+    }
+
+    // Otherwise, this is not something we can reason about.
+    noteUnknown();
+  }
+
+  // Note either a Literal or a Name.
   template<typename T> void note(T curr) {
     if (std::get_if<None>(&value)) {
       // This is the first value.
@@ -120,6 +141,17 @@ public:
     return std::get<Name>(value);
   }
 
+  // Assuming we have a single value, make an expression containing that value.
+  Expression* makeExpression(Module& wasm) {
+    Builder builder(wasm);
+    if (isConstantLiteral()) {
+      return builder.makeConstantExpression(getConstantLiteral());
+    } else {
+      auto name = getConstantGlobal();
+      return builder.makeGlobalGet(name, wasm.getGlobal(name)->type);
+    }
+  }
+
   // Returns whether we have ever noted a value.
   bool hasNoted() const { return !std::get_if<None>(&value); }
 
diff --git a/src/passes/ConstantFieldPropagation.cpp b/src/passes/ConstantFieldPropagation.cpp
index 44e74f2d4..1755c97f3 100644
--- a/src/passes/ConstantFieldPropagation.cpp
+++ b/src/passes/ConstantFieldPropagation.cpp
@@ -29,7 +29,6 @@
 
 #include "ir/module-utils.h"
 #include "ir/possible-constant.h"
-#include "ir/properties.h"
 #include "ir/struct-utils.h"
 #include "ir/utils.h"
 #include "pass.h"
@@ -101,12 +100,7 @@ struct FunctionOptimizer : public WalkerPass<PostWalker<FunctionOptimizer>> {
     // ref.as_non_null (we need to trap as the get would have done so), plus the
     // constant value. (Leave it to further optimizations to get rid of the
     // ref.)
-    Expression* value;
-    if (info.isConstantLiteral()) {
-      value = builder.makeConstantExpression(info.getConstantLiteral());
-    } else {
-      value = builder.makeGlobalGet(info.getConstantGlobal(), curr->type);
-    }
+    Expression* value = info.makeExpression(*getModule());
     replaceCurrent(builder.makeSequence(
       builder.makeDrop(builder.makeRefAs(RefAsNonNull, curr->ref)), value));
     changed = true;
@@ -145,23 +139,7 @@ struct PCVScanner
                       HeapType type,
                       Index index,
                       PossibleConstantValues& info) {
-    // If this is a constant literal value, note that.
-    if (Properties::isConstantExpression(expr)) {
-      info.note(Properties::getLiteral(expr));
-      return;
-    }
-
-    // If this is an immutable global that we get, note that.
-    if (auto* get = expr->dynCast<GlobalGet>()) {
-      auto* global = getModule()->getGlobal(get->name);
-      if (global->mutable_ == Immutable) {
-        info.note(get->name);
-        return;
-      }
-    }
-
-    // Otherwise, this is not something we can reason about.
-    info.noteUnknown();
+    info.note(expr, *getModule());
   }
 
   void noteDefault(Type fieldType,
diff --git a/src/passes/param-utils.cpp b/src/passes/param-utils.cpp
index ae641fd26..cf7873dc0 100644
--- a/src/passes/param-utils.cpp
+++ b/src/passes/param-utils.cpp
@@ -200,25 +200,14 @@ SortedVector applyConstantValues(const std::vector<Function*>& funcs,
   auto numParams = first->getNumParams();
   for (Index i = 0; i < numParams; i++) {
     PossibleConstantValues value;
-
-    // Processes one operand.
-    auto processOperand = [&](Expression* operand) {
-      if (auto* c = operand->dynCast<Const>()) {
-        value.note(c->value);
-        return;
-      }
-      // TODO: refnull, immutable globals, etc.
-      // Not a constant, give up
-      value.noteUnknown();
-    };
     for (auto* call : calls) {
-      processOperand(call->operands[i]);
+      value.note(call->operands[i], *module);
       if (!value.isConstant()) {
         break;
       }
     }
     for (auto* call : callRefs) {
-      processOperand(call->operands[i]);
+      value.note(call->operands[i], *module);
       if (!value.isConstant()) {
         break;
       }
@@ -232,8 +221,7 @@ SortedVector applyConstantValues(const std::vector<Function*>& funcs,
     Builder builder(*module);
     for (auto* func : funcs) {
       func->body = builder.makeSequence(
-        builder.makeLocalSet(i, builder.makeConst(value.getConstantLiteral())),
-        func->body);
+        builder.makeLocalSet(i, value.makeExpression(*module)), func->body);
     }
     optimized.insert(i);
   }