Add Module::get_code() helper method

Author: chfast

Diff for: lib/fizzy/execute.cpp

@@ -474,10 +474,7 @@ ExecutionResult execute(
     if (func_idx < instance.imported_functions.size())
         return instance.imported_functions[func_idx].function(instance, args, depth);
 
-    const auto code_idx = func_idx - instance.imported_functions.size();
-    assert(code_idx < instance.module.codesec.size());
-
-    const auto& code = instance.module.codesec[code_idx];
+    const auto& code = instance.module.get_code(func_idx);
     auto* const memory = instance.memory.get();
 
     OperandStack stack(args, code.local_count, static_cast<size_t>(code.max_stack_height));

Diff for: lib/fizzy/module.hpp

@@ -76,6 +76,14 @@ struct Module
                    globalsec[idx - imported_global_types.size()].type;
     }
 
+    const Code& get_code(FuncIdx func_idx) const noexcept
+    {
+        assert(func_idx >= imported_function_types.size());  // Cannot be imported function.
+        const auto code_idx = func_idx - imported_function_types.size();
+        assert(code_idx < codesec.size());
+        return codesec[code_idx];
+    }
+
     bool has_table() const noexcept { return !tablesec.empty() || !imported_table_types.empty(); }
 
     bool has_memory() const noexcept

Diff for: test/unittests/module_test.cpp

@@ -15,12 +15,12 @@ TEST(module, functions)
     /* wat2wasm
       (func (import "m" "f1") (param i32 i32) (result i32))
       (func)
-      (func (param i64))
+      (func (param i64) (local i32))
       (func (result f32) (f32.const 0))
     */
     const auto bin = from_hex(
         "0061736d0100000001120460027f7f017f60000060017e006000017d020801016d02663100000304030102030a"
-        "0f0302000b02000b070043000000000b");
+        "110302000b0401017f0b070043000000000b");
     const auto module = parse(bin);
 
     ASSERT_EQ(module.get_function_count(), 4);
@@ -29,6 +29,13 @@ TEST(module, functions)
     EXPECT_EQ(module.get_function_type(1), (FuncType{}));
     EXPECT_EQ(module.get_function_type(2), (FuncType{{ValType::i64}, {}}));
     EXPECT_EQ(module.get_function_type(3), (FuncType{{}, {ValType::f32}}));
+
+    EXPECT_EQ(module.get_code(1).instructions.size(), 1);
+    EXPECT_EQ(module.get_code(1).local_count, 0);
+    EXPECT_EQ(module.get_code(2).instructions.size(), 1);
+    EXPECT_EQ(module.get_code(2).local_count, 1);
+    EXPECT_EQ(module.get_code(3).instructions.size(), 2);
+    EXPECT_EQ(module.get_code(3).local_count, 0);
 }
 
 TEST(module, globals)