[Interpreter] i32.mul (#7268)

Building on top of #7227, i32.mul is implemented and tested.

Author: ashleynh

src/interpreter/interpreter.cpp

@@ -90,15 +90,20 @@ struct ExpressionInterpreter : OverriddenVisitor<ExpressionInterpreter, Flow> {
   Flow visitBinary(Binary* curr) {
     auto rhs = pop();
     auto lhs = pop();
-    // TODO: switch-case over all operations.
-    if (curr->op == AddInt32) {
-      push(lhs.add(rhs));
-      return {};
-    } else if (curr->op == SubInt32) {
-      push(lhs.sub(rhs));
-      return {};
+    // TODO: add support for all operations.
+    switch (curr->op) {
+      case AddInt32:
+        push(lhs.add(rhs));
+        return {};
+      case SubInt32:
+        push(lhs.sub(rhs));
+        return {};
+      case MulInt32:
+        push(lhs.mul(rhs));
+        return {};
+      default:
+        WASM_UNREACHABLE("TODO");
     }
-    WASM_UNREACHABLE("TODO");
   }
   Flow visitSelect(Select* curr) { WASM_UNREACHABLE("TODO"); }
   Flow visitDrop(Drop* curr) { WASM_UNREACHABLE("TODO"); }

test/gtest/interpreter.cpp

@@ -58,3 +58,20 @@ TEST(InterpreterTest, SubI32) {
 
   EXPECT_EQ(results, expected);
 }
+
+TEST(InterpreterTest, MulI32) {
+  Module wasm;
+  IRBuilder builder(wasm);
+
+  ASSERT_FALSE(builder.makeConst(Literal(uint32_t(1))).getErr());
+  ASSERT_FALSE(builder.makeConst(Literal(uint32_t(2))).getErr());
+  ASSERT_FALSE(builder.makeBinary(MulInt32).getErr());
+
+  auto expr = builder.build();
+  ASSERT_FALSE(expr.getErr());
+
+  auto results = Interpreter{}.run(*expr);
+  std::vector<Literal> expected{Literal(uint32_t(2))};
+
+  EXPECT_EQ(results, expected);
+}