[wasm] Test argument passing in the interpreter entry

Test the wasm interpreter entry stub by creating two wasm functions A
and B, make A pass arguments to B, then redirect B to be executed in the
interpreter.
Test different number and types or arguments.

BUG=v8:5822
R=titzer@chromium.org

Review-Url: https://codereview.chromium.org/2651793003
Cr-Commit-Position: refs/heads/master@{#43353}

src/wasm/wasm-debug.cc

@@ -273,6 +273,11 @@ class InterpreterHandle {
     return std::unique_ptr<wasm::InterpretedFrame>(
         new wasm::InterpretedFrame(thread->GetMutableFrame(idx)));
   }
+
+  uint64_t NumInterpretedCalls() {
+    DCHECK_EQ(1, interpreter()->GetThreadCount());
+    return interpreter()->GetThread(0)->NumInterpretedCalls();
+  }
 };
 
 InterpreterHandle* GetOrCreateInterpreterHandle(
@@ -294,6 +299,12 @@ InterpreterHandle* GetInterpreterHandle(WasmDebugInfo* debug_info) {
   return Managed<InterpreterHandle>::cast(handle_obj)->get();
 }
 
+InterpreterHandle* GetInterpreterHandleOrNull(WasmDebugInfo* debug_info) {
+  Object* handle_obj = debug_info->get(WasmDebugInfo::kInterpreterHandle);
+  if (handle_obj->IsUndefined(debug_info->GetIsolate())) return nullptr;
+  return Managed<InterpreterHandle>::cast(handle_obj)->get();
+}
+
 int GetNumFunctions(WasmInstanceObject* instance) {
   size_t num_functions =
       instance->compiled_module()->module()->functions.size();
@@ -345,26 +356,6 @@ void RedirectCallsitesInInstance(Isolate* isolate, WasmInstanceObject* instance,
   }
 }
 
-void EnsureRedirectToInterpreter(Isolate* isolate,
-                                 Handle<WasmDebugInfo> debug_info,
-                                 int func_index) {
-  Handle<FixedArray> interpreted_functions =
-      GetOrCreateInterpretedFunctions(isolate, debug_info);
-  if (!interpreted_functions->get(func_index)->IsUndefined(isolate)) return;
-
-  Handle<WasmInstanceObject> instance(debug_info->wasm_instance(), isolate);
-  Handle<Code> new_code = compiler::CompileWasmInterpreterEntry(
-      isolate, func_index,
-      instance->compiled_module()->module()->functions[func_index].sig,
-      instance);
-
-  Handle<FixedArray> code_table = instance->compiled_module()->code_table();
-  Handle<Code> old_code(Code::cast(code_table->get(func_index)), isolate);
-  interpreted_functions->set(func_index, *new_code);
-
-  RedirectCallsitesInInstance(isolate, *instance, *old_code, *new_code);
-}
-
 }  // namespace
 
 Handle<WasmDebugInfo> WasmDebugInfo::New(Handle<WasmInstanceObject> instance) {
@@ -400,12 +391,34 @@ void WasmDebugInfo::SetBreakpoint(Handle<WasmDebugInfo> debug_info,
                                   int func_index, int offset) {
   Isolate* isolate = debug_info->GetIsolate();
   InterpreterHandle* handle = GetOrCreateInterpreterHandle(isolate, debug_info);
-  WasmInterpreter* interpreter = handle->interpreter();
-  DCHECK_LE(0, func_index);
-  DCHECK_GT(handle->module()->functions.size(), func_index);
+  RedirectToInterpreter(debug_info, func_index);
   const WasmFunction* func = &handle->module()->functions[func_index];
-  interpreter->SetBreakpoint(func, offset, true);
-  EnsureRedirectToInterpreter(isolate, debug_info, func_index);
+  handle->interpreter()->SetBreakpoint(func, offset, true);
+}
+
+void WasmDebugInfo::RedirectToInterpreter(Handle<WasmDebugInfo> debug_info,
+                                          int func_index) {
+  Isolate* isolate = debug_info->GetIsolate();
+  DCHECK_LE(0, func_index);
+  DCHECK_GT(debug_info->wasm_instance()->module()->functions.size(),
+            func_index);
+  Handle<FixedArray> interpreted_functions =
+      GetOrCreateInterpretedFunctions(isolate, debug_info);
+  if (!interpreted_functions->get(func_index)->IsUndefined(isolate)) return;
+
+  // Ensure that the interpreter is instantiated.
+  GetOrCreateInterpreterHandle(isolate, debug_info);
+  Handle<WasmInstanceObject> instance(debug_info->wasm_instance(), isolate);
+  Handle<Code> new_code = compiler::CompileWasmInterpreterEntry(
+      isolate, func_index,
+      instance->compiled_module()->module()->functions[func_index].sig,
+      instance);
+
+  Handle<FixedArray> code_table = instance->compiled_module()->code_table();
+  Handle<Code> old_code(Code::cast(code_table->get(func_index)), isolate);
+  interpreted_functions->set(func_index, *new_code);
+
+  RedirectCallsitesInInstance(isolate, *instance, *old_code, *new_code);
 }
 
 void WasmDebugInfo::PrepareStep(StepAction step_action) {
@@ -427,3 +440,8 @@ std::unique_ptr<wasm::InterpretedFrame> WasmDebugInfo::GetInterpretedFrame(
     Address frame_pointer, int idx) {
   return GetInterpreterHandle(this)->GetInterpretedFrame(frame_pointer, idx);
 }
+
+uint64_t WasmDebugInfo::NumInterpretedCalls() {
+  auto handle = GetInterpreterHandleOrNull(this);
+  return handle ? handle->NumInterpretedCalls() : 0;
+}

src/wasm/wasm-interpreter.cc

@@ -935,6 +935,7 @@ class ThreadImpl {
   void PushFrame(const WasmFunction* function, WasmVal* args) {
     InterpreterCode* code = codemap()->FindCode(function);
     CHECK_NOT_NULL(code);
+    ++num_interpreted_calls_;
     frames_.push_back({code, 0, 0, stack_.size()});
     for (size_t i = 0; i < function->sig->parameter_count(); ++i) {
       stack_.push_back(args[i]);
@@ -1009,6 +1010,8 @@ class ThreadImpl {
 
   bool PossibleNondeterminism() { return possible_nondeterminism_; }
 
+  uint64_t NumInterpretedCalls() { return num_interpreted_calls_; }
+
   void AddBreakFlags(uint8_t flags) { break_flags_ |= flags; }
 
   void ClearBreakFlags() { break_flags_ = WasmInterpreter::BreakFlag::None; }
@@ -1044,6 +1047,7 @@ class ThreadImpl {
   TrapReason trap_reason_ = kTrapCount;
   bool possible_nondeterminism_ = false;
   uint8_t break_flags_ = 0;  // a combination of WasmInterpreter::BreakFlag
+  uint64_t num_interpreted_calls_ = 0;
 
   CodeMap* codemap() { return codemap_; }
   WasmInstance* instance() { return instance_; }
@@ -1059,6 +1063,7 @@ class ThreadImpl {
   void PushFrame(InterpreterCode* code, pc_t call_pc, pc_t ret_pc) {
     CHECK_NOT_NULL(code);
     DCHECK(!frames_.empty());
+    ++num_interpreted_calls_;
     frames_.back().call_pc = call_pc;
     frames_.back().ret_pc = ret_pc;
     size_t arity = code->function->sig->parameter_count();
@@ -1797,6 +1802,9 @@ WasmVal WasmInterpreter::Thread::GetReturnValue(int index) {
 bool WasmInterpreter::Thread::PossibleNondeterminism() {
   return ToImpl(this)->PossibleNondeterminism();
 }
+uint64_t WasmInterpreter::Thread::NumInterpretedCalls() {
+  return ToImpl(this)->NumInterpretedCalls();
+}
 void WasmInterpreter::Thread::AddBreakFlags(uint8_t flags) {
   ToImpl(this)->AddBreakFlags(flags);
 }

src/wasm/wasm-interpreter.h

@@ -148,11 +148,15 @@ class V8_EXPORT_PRIVATE WasmInterpreter {
     const InterpretedFrame GetFrame(int index);
     InterpretedFrame GetMutableFrame(int index);
     WasmVal GetReturnValue(int index = 0);
+
     // Returns true if the thread executed an instruction which may produce
     // nondeterministic results, e.g. float div, float sqrt, and float mul,
     // where the sign bit of a NaN is nondeterministic.
     bool PossibleNondeterminism();
 
+    // Returns the number of calls / function frames executed on this thread.
+    uint64_t NumInterpretedCalls();
+
     // Thread-specific breakpoints.
     // TODO(wasm): Implement this once we support multiple threads.
     // bool SetBreakpoint(const WasmFunction* function, int pc, bool enabled);

src/wasm/wasm-macro-gen.h

@@ -373,14 +373,15 @@ class LocalDeclEncoder {
       static_cast<byte>(bit_cast<uint32_t>(static_cast<float>(val)) >> 16), \
       static_cast<byte>(bit_cast<uint32_t>(static_cast<float>(val)) >> 24)
 #define WASM_F64(val)                                                        \
-  kExprF64Const, static_cast<byte>(bit_cast<uint64_t>(val)), \
-      static_cast<byte>(bit_cast<uint64_t>(val) >> 8),       \
-      static_cast<byte>(bit_cast<uint64_t>(val) >> 16),      \
-      static_cast<byte>(bit_cast<uint64_t>(val) >> 24),      \
-      static_cast<byte>(bit_cast<uint64_t>(val) >> 32),      \
-      static_cast<byte>(bit_cast<uint64_t>(val) >> 40),      \
-      static_cast<byte>(bit_cast<uint64_t>(val) >> 48),      \
-      static_cast<byte>(bit_cast<uint64_t>(val) >> 56)
+  kExprF64Const,                                                             \
+      static_cast<byte>(bit_cast<uint64_t>(static_cast<double>(val))),       \
+      static_cast<byte>(bit_cast<uint64_t>(static_cast<double>(val)) >> 8),  \
+      static_cast<byte>(bit_cast<uint64_t>(static_cast<double>(val)) >> 16), \
+      static_cast<byte>(bit_cast<uint64_t>(static_cast<double>(val)) >> 24), \
+      static_cast<byte>(bit_cast<uint64_t>(static_cast<double>(val)) >> 32), \
+      static_cast<byte>(bit_cast<uint64_t>(static_cast<double>(val)) >> 40), \
+      static_cast<byte>(bit_cast<uint64_t>(static_cast<double>(val)) >> 48), \
+      static_cast<byte>(bit_cast<uint64_t>(static_cast<double>(val)) >> 56)
 #define WASM_GET_LOCAL(index) kExprGetLocal, static_cast<byte>(index)
 #define WASM_SET_LOCAL(index, val) val, kExprSetLocal, static_cast<byte>(index)
 #define WASM_TEE_LOCAL(index, val) val, kExprTeeLocal, static_cast<byte>(index)

src/wasm/wasm-objects.h

@@ -420,8 +420,15 @@ class WasmDebugInfo : public FixedArray {
   static bool IsDebugInfo(Object*);
   static WasmDebugInfo* cast(Object*);
 
+  // Set a breakpoint in the given function at the given byte offset within that
+  // function. This will redirect all future calls to this function to the
+  // interpreter and will always pause at the given offset.
   static void SetBreakpoint(Handle<WasmDebugInfo>, int func_index, int offset);
 
+  // Make a function always execute in the interpreter without setting a
+  // breakpoints.
+  static void RedirectToInterpreter(Handle<WasmDebugInfo>, int func_index);
+
   void PrepareStep(StepAction);
 
   void RunInterpreter(int func_index, uint8_t* arg_buffer);
@@ -434,6 +441,9 @@ class WasmDebugInfo : public FixedArray {
   std::unique_ptr<wasm::InterpretedFrame> GetInterpretedFrame(
       Address frame_pointer, int idx);
 
+  // Returns the number of calls / function frames executed in the interpreter.
+  uint64_t NumInterpretedCalls();
+
   DECLARE_GETTER(wasm_instance, WasmInstanceObject);
 };
 

test/cctest/BUILD.gn

@@ -195,6 +195,7 @@ v8_executable("cctest") {
     "wasm/test-run-wasm-relocation.cc",
     "wasm/test-run-wasm.cc",
     "wasm/test-wasm-breakpoints.cc",
+    "wasm/test-wasm-interpreter-entry.cc",
     "wasm/test-wasm-stack.cc",
     "wasm/test-wasm-trap-position.cc",
     "wasm/wasm-run-utils.h",

test/cctest/cctest.gyp

@@ -216,6 +216,7 @@
       'wasm/test-run-wasm-module.cc',
       'wasm/test-run-wasm-relocation.cc',
       'wasm/test-wasm-breakpoints.cc',
+      'wasm/test-wasm-interpreter-entry.cc',
       'wasm/test-wasm-stack.cc',
       'wasm/test-wasm-trap-position.cc',
       'wasm/wasm-run-utils.h',

test/cctest/wasm/test-wasm-interpreter-entry.cc

+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <cstdint>
+
+#include "src/wasm/wasm-macro-gen.h"
+#include "src/wasm/wasm-objects.h"
+
+#include "test/cctest/cctest.h"
+#include "test/cctest/compiler/value-helper.h"
+#include "test/cctest/wasm/wasm-run-utils.h"
+
+using namespace v8::internal;
+using namespace v8::internal::wasm;
+namespace debug = v8::debug;
+
+/**
+ * We test the interface from Wasm compiled code to the Wasm interpreter by
+ * building a module with two functions. The external function is called from
+ * this test, and will be compiled code. It takes its arguments and passes them
+ * on to the internal function, which will be redirected to the interpreter.
+ * If the internal function has an i64 parameter, is has to be replaced by two
+ * i32 parameters on the external function.
+ * The internal function just converts all its arguments to f64, sums them up
+ * and returns the sum.
+ */
+namespace {
+
+template <typename T>
+class ArgPassingHelper {
+ public:
+  ArgPassingHelper(WasmRunnerBase& runner, WasmFunctionCompiler& inner_compiler,
+                   std::initializer_list<uint8_t> bytes_inner_function,
+                   std::initializer_list<uint8_t> bytes_outer_function,
+                   const T& expected_lambda)
+      : isolate_(runner.main_isolate()),
+        expected_lambda_(expected_lambda),
+        debug_info_(WasmInstanceObject::GetOrCreateDebugInfo(
+            runner.module().instance_object())) {
+    std::vector<uint8_t> inner_code{bytes_inner_function};
+    inner_compiler.Build(inner_code.data(),
+                         inner_code.data() + inner_code.size());
+
+    std::vector<uint8_t> outer_code{bytes_outer_function};
+    runner.Build(outer_code.data(), outer_code.data() + outer_code.size());
+
+    WasmDebugInfo::RedirectToInterpreter(debug_info_,
+                                         inner_compiler.function_index());
+    main_fun_wrapper_ = runner.module().WrapCode(runner.function_index());
+  }
+
+  template <typename... Args>
+  void CheckCall(Args... args) {
+    Handle<Object> arg_objs[] = {isolate_->factory()->NewNumber(args)...};
+
+    uint64_t num_interpreted_before = debug_info_->NumInterpretedCalls();
+    Handle<Object> global(isolate_->context()->global_object(), isolate_);
+    MaybeHandle<Object> retval = Execution::Call(
+        isolate_, main_fun_wrapper_, global, arraysize(arg_objs), arg_objs);
+    uint64_t num_interpreted_after = debug_info_->NumInterpretedCalls();
+    // Check that we really went through the interpreter.
+    CHECK_EQ(num_interpreted_before + 1, num_interpreted_after);
+    // Check the result.
+    double result = retval.ToHandleChecked()->Number();
+    double expected = expected_lambda_(args...);
+    CHECK_DOUBLE_EQ(expected, result);
+  }
+
+ private:
+  Isolate* isolate_;
+  T expected_lambda_;
+  Handle<WasmDebugInfo> debug_info_;
+  Handle<JSFunction> main_fun_wrapper_;
+};
+
+template <typename T>
+static ArgPassingHelper<T> GetHelper(
+    WasmRunnerBase& runner, WasmFunctionCompiler& inner_compiler,
+    std::initializer_list<uint8_t> bytes_inner_function,
+    std::initializer_list<uint8_t> bytes_outer_function,
+    const T& expected_lambda) {
+  return ArgPassingHelper<T>(runner, inner_compiler, bytes_inner_function,
+                             bytes_outer_function, expected_lambda);
+}
+
+}  // namespace
+
+TEST(TestArgumentPassing_int32) {
+  WasmRunner<int32_t, int32_t> runner(kExecuteCompiled);
+  WasmFunctionCompiler& f2 = runner.NewFunction<int32_t, int32_t>();
+
+  auto helper = GetHelper(
+      runner, f2,
+      {// Return 2*<0> + 1.
+       WASM_I32_ADD(WASM_I32_MUL(WASM_I32V_1(2), WASM_GET_LOCAL(0)), WASM_ONE)},
+      {// Call f2 with param <0>.
+       WASM_GET_LOCAL(0), WASM_CALL_FUNCTION0(f2.function_index())},
+      [](int32_t a) { return 2 * a + 1; });
+
+  std::vector<int32_t> test_values = compiler::ValueHelper::int32_vector();
+  for (int32_t v : test_values) helper.CheckCall(v);
+}
+
+TEST(TestArgumentPassing_int64) {
+  WasmRunner<double, int32_t, int32_t> runner(kExecuteCompiled);
+  WasmFunctionCompiler& f2 = runner.NewFunction<double, int64_t>();
+
+  auto helper = GetHelper(
+      runner, f2,
+      {// Return (double)<0>.
+       WASM_F64_SCONVERT_I64(WASM_GET_LOCAL(0))},
+      {// Call f2 with param (<0> | (<1> << 32)).
+       WASM_I64_IOR(WASM_I64_UCONVERT_I32(WASM_GET_LOCAL(0)),
+                    WASM_I64_SHL(WASM_I64_UCONVERT_I32(WASM_GET_LOCAL(1)),
+                                 WASM_I64V_1(32))),
+       WASM_CALL_FUNCTION0(f2.function_index())},
+      [](int32_t a, int32_t b) {
+        int64_t a64 = static_cast<int64_t>(a) & 0xffffffff;
+        int64_t b64 = static_cast<int64_t>(b) << 32;
+        return static_cast<double>(a64 | b64);
+      });
+
+  std::vector<int32_t> test_values_i32 = compiler::ValueHelper::int32_vector();
+  for (int32_t v1 : test_values_i32) {
+    for (int32_t v2 : test_values_i32) {
+      helper.CheckCall(v1, v2);
+    }
+  }
+
+  std::vector<int64_t> test_values_i64 = compiler::ValueHelper::int64_vector();
+  for (int64_t v : test_values_i64) {
+    int32_t v1 = static_cast<int32_t>(v);
+    int32_t v2 = static_cast<int32_t>(v >> 32);
+    helper.CheckCall(v1, v2);
+    helper.CheckCall(v2, v1);
+  }
+}
+
+TEST(TestArgumentPassing_float_double) {
+  WasmRunner<double, float> runner(kExecuteCompiled);
+  WasmFunctionCompiler& f2 = runner.NewFunction<double, float>();
+
+  auto helper = GetHelper(
+      runner, f2,
+      {// Return 2*(double)<0> + 1.
+       WASM_F64_ADD(
+           WASM_F64_MUL(WASM_F64(2), WASM_F64_CONVERT_F32(WASM_GET_LOCAL(0))),
+           WASM_F64(1))},
+      {// Call f2 with param <0>.
+       WASM_GET_LOCAL(0), WASM_CALL_FUNCTION0(f2.function_index())},
+      [](float f) { return 2. * static_cast<double>(f) + 1.; });
+
+  std::vector<float> test_values = compiler::ValueHelper::float32_vector();
+  for (float f : test_values) helper.CheckCall(f);
+}
+
+TEST(TestArgumentPassing_double_double) {
+  WasmRunner<double, double, double> runner(kExecuteCompiled);
+  WasmFunctionCompiler& f2 = runner.NewFunction<double, double, double>();
+
+  auto helper = GetHelper(runner, f2,
+                          {// Return <0> + <1>.
+                           WASM_F64_ADD(WASM_GET_LOCAL(0), WASM_GET_LOCAL(1))},
+                          {// Call f2 with params <0>, <1>.
+                           WASM_GET_LOCAL(0), WASM_GET_LOCAL(1),
+                           WASM_CALL_FUNCTION0(f2.function_index())},
+                          [](double a, double b) { return a + b; });
+
+  std::vector<double> test_values = compiler::ValueHelper::float64_vector();
+  for (double d1 : test_values) {
+    for (double d2 : test_values) {
+      helper.CheckCall(d1, d2);
+    }
+  }
+}
+
+TEST(TestArgumentPassing_AllTypes) {
+  // The second and third argument will be combined to an i64.
+  WasmRunner<double, int, int, int, float, double> runner(kExecuteCompiled);
+  WasmFunctionCompiler& f2 =
+      runner.NewFunction<double, int, int64_t, float, double>();
+
+  auto helper = GetHelper(
+      runner, f2,
+      {
+          // Convert all arguments to double, add them and return the sum.
+          WASM_F64_ADD(          // <0+1+2> + <3>
+              WASM_F64_ADD(      // <0+1> + <2>
+                  WASM_F64_ADD(  // <0> + <1>
+                      WASM_F64_SCONVERT_I32(
+                          WASM_GET_LOCAL(0)),  // <0> to double
+                      WASM_F64_SCONVERT_I64(
+                          WASM_GET_LOCAL(1))),               // <1> to double
+                  WASM_F64_CONVERT_F32(WASM_GET_LOCAL(2))),  // <2> to double
+              WASM_GET_LOCAL(3))                             // <3>
+      },
+      {WASM_GET_LOCAL(0),                                      // first arg
+       WASM_I64_IOR(WASM_I64_UCONVERT_I32(WASM_GET_LOCAL(1)),  // second arg
+                    WASM_I64_SHL(WASM_I64_UCONVERT_I32(WASM_GET_LOCAL(2)),
+                                 WASM_I64V_1(32))),
+       WASM_GET_LOCAL(3),  // third arg
+       WASM_GET_LOCAL(4),  // fourth arg
+       WASM_CALL_FUNCTION0(f2.function_index())},
+      [](int32_t a, int32_t b, int32_t c, float d, double e) {
+        return 0. + a + (static_cast<int64_t>(b) & 0xffffffff) +
+               ((static_cast<int64_t>(c) & 0xffffffff) << 32) + d + e;
+      });
+
+  auto CheckCall = [&](int32_t a, int64_t b, float c, double d) {
+    int32_t b0 = static_cast<int32_t>(b);
+    int32_t b1 = static_cast<int32_t>(b >> 32);
+    helper.CheckCall(a, b0, b1, c, d);
+    helper.CheckCall(a, b1, b0, c, d);
+  };
+
+  std::vector<int32_t> test_values_i32 = compiler::ValueHelper::int32_vector();
+  std::vector<int64_t> test_values_i64 = compiler::ValueHelper::int64_vector();
+  std::vector<float> test_values_f32 = compiler::ValueHelper::float32_vector();
+  std::vector<double> test_values_f64 = compiler::ValueHelper::float64_vector();
+  size_t max_len =
+      std::max(std::max(test_values_i32.size(), test_values_i64.size()),
+               std::max(test_values_f32.size(), test_values_f64.size()));
+  for (size_t i = 0; i < max_len; ++i) {
+    int32_t i32 = test_values_i32[i % test_values_i32.size()];
+    int64_t i64 = test_values_i64[i % test_values_i64.size()];
+    float f32 = test_values_f32[i % test_values_f32.size()];
+    double f64 = test_values_f64[i % test_values_f64.size()];
+    CheckCall(i32, i64, f32, f64);
+  }
+}

test/cctest/wasm/wasm-run-utils.h

@@ -564,9 +564,17 @@ class WasmFunctionCompiler : private GraphAndBuilders {
     Handle<WasmCompiledModule> compiled_module(
         testing_module_->instance_object()->compiled_module(), isolate());
     Handle<FixedArray> code_table = compiled_module->code_table();
-    code_table = FixedArray::SetAndGrow(code_table, function_index(), code);
+    if (static_cast<int>(function_index()) >= code_table->length()) {
+      Handle<FixedArray> new_arr = isolate()->factory()->NewFixedArray(
+          static_cast<int>(function_index()) + 1);
+      code_table->CopyTo(0, *new_arr, 0, code_table->length());
+      code_table = new_arr;
       compiled_module->set_code_table(code_table);
     }
+    DCHECK(code_table->get(static_cast<int>(function_index()))
+               ->IsUndefined(isolate()));
+    code_table->set(static_cast<int>(function_index()), *code);
+  }
 
   byte AllocateLocal(ValueType type) {
     uint32_t index = local_decls.AddLocals(1, type);