[stubs] A new approach to TF stubs

test/cctest/compiler/function-tester.h

 // Copyright 2014 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.
 
 #ifndef V8_CCTEST_COMPILER_FUNCTION_TESTER_H_
 #define V8_CCTEST_COMPILER_FUNCTION_TESTER_H_
 
 #include "src/ast/ast-numbering.h"
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
@@ skipping 17 matching lines @@
       : isolate(main_isolate()),
         function((FLAG_allow_natives_syntax = true, NewFunction(source))),
         flags_(flags) {
     Compile(function);
     const uint32_t supported_flags =
         CompilationInfo::kFunctionContextSpecializing |
         CompilationInfo::kInliningEnabled | CompilationInfo::kTypingEnabled;
     CHECK_EQ(0u, flags_ & ~supported_flags);
   }
 
-  // TODO(turbofan): generalize FunctionTester to work with N arguments. Now, it
-  // can handle up to four.
-  explicit FunctionTester(Graph* graph)
+  FunctionTester(Graph* graph, int param_count)
       : isolate(main_isolate()),
-        function(NewFunction("(function(a,b,c,d){})")),
+        function(NewFunction(BuildFunction(param_count).c_str())),
         flags_(0) {
     CompileGraph(graph);
   }
 
+  FunctionTester(const CallInterfaceDescriptor& descriptor, Handle<Code> code)
+      : isolate(main_isolate()),
+        function(
+            (FLAG_allow_natives_syntax = true,
+             NewFunction(BuildFunctionFromDescriptor(descriptor).c_str()))),
+        flags_(0) {
+    Compile(function);
+    function->ReplaceCode(*code);
+  }
+
   Isolate* isolate;
   Handle<JSFunction> function;
 
+  MaybeHandle<Object> Call() {
+    return Execution::Call(isolate, function, undefined(), 0, nullptr);
+  }
+
   MaybeHandle<Object> Call(Handle<Object> a, Handle<Object> b) {
     Handle<Object> args[] = {a, b};
     return Execution::Call(isolate, function, undefined(), 2, args);
   }
 
   MaybeHandle<Object> Call(Handle<Object> a, Handle<Object> b, Handle<Object> c,
                            Handle<Object> d) {
     Handle<Object> args[] = {a, b, c, d};
     return Execution::Call(isolate, function, undefined(), 4, args);
   }
@@ skipping 113 matching lines @@
 
     Pipeline pipeline(&info);
     Handle<Code> code = pipeline.GenerateCode();
     CHECK(!code.is_null());
     info.dependencies()->Commit(code);
     info.context()->native_context()->AddOptimizedCode(*code);
     function->ReplaceCode(*code);
     return function;
   }
 
-  static Handle<JSFunction> ForMachineGraph(Graph* graph) {
+  static Handle<JSFunction> ForMachineGraph(Graph* graph, int param_count) {
     JSFunction* p = NULL;
     {  // because of the implicit handle scope of FunctionTester.
-      FunctionTester f(graph);
+      FunctionTester f(graph, param_count);
       p = *f.function;
     }
     return Handle<JSFunction>(p);  // allocated in outer handle scope.
   }
 
  private:
   uint32_t flags_;
 
+  std::string BuildFunction(int param_count) {
+    std::string function_string = "(function(";
+    if (param_count > 0) {
+      char next = 'a';
+      function_string += next;
+      while (param_count-- > 0) {
+        function_string += ',';
+        function_string += ++next;
+      }
+    }
+    function_string += "){})";
+    return function_string;
+  }
+
+  std::string BuildFunctionFromDescriptor(
+      const CallInterfaceDescriptor& descriptor) {
+    return BuildFunction(descriptor.GetParameterCount());
+  }
+
   // Compile the given machine graph instead of the source of the function
   // and replace the JSFunction's code with the result.
   Handle<JSFunction> CompileGraph(Graph* graph) {
     Zone zone;
     ParseInfo parse_info(&zone, function);
     CompilationInfo info(&parse_info);
 
     CHECK(Parser::ParseStatic(info.parse_info()));
     info.SetOptimizing(BailoutId::None(),
                        Handle<Code>(function->shared()->code()));
     CHECK(Compiler::Analyze(info.parse_info()));
     CHECK(Compiler::EnsureDeoptimizationSupport(&info));
 
     Handle<Code> code = Pipeline::GenerateCodeForTesting(&info, graph);
     CHECK(!code.is_null());
     function->ReplaceCode(*code);
     return function;
   }
 };
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CCTEST_COMPILER_FUNCTION_TESTER_H_