Recognize leaf functions: skip stack check and populating the pc slot, store the pc slot lazily in …

runtime/vm/flow_graph_compiler.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/debugger.h"
 #include "vm/il_printer.h"
@@ skipping 13 matching lines @@
 DECLARE_FLAG(bool, intrinsify);
 DECLARE_FLAG(bool, report_usage_count);
 DECLARE_FLAG(bool, trace_functions);
 DECLARE_FLAG(int, optimization_counter_threshold);
 
 
 FlowGraphCompiler::FlowGraphCompiler(
     Assembler* assembler,
     const ParsedFunction& parsed_function,
     const GrowableArray<BlockEntryInstr*>& block_order,
-    bool is_optimizing)
+    bool is_optimizing,
+    bool is_leaf)
     : assembler_(assembler),
       parsed_function_(parsed_function),
       block_order_(block_order),
       current_block_(NULL),
       exception_handlers_list_(NULL),
       pc_descriptors_list_(NULL),
       stackmap_builder_(NULL),
       block_info_(block_order.length()),
       deopt_stubs_(),
       is_optimizing_(is_optimizing),
+      is_dart_leaf_(is_leaf),
       bool_true_(Bool::ZoneHandle(Bool::True())),
       bool_false_(Bool::ZoneHandle(Bool::False())),
       double_class_(Class::ZoneHandle(
           Isolate::Current()->object_store()->double_class())),
       frame_register_allocator_(this, is_optimizing) {
   ASSERT(assembler != NULL);
 }
 
 
 FlowGraphCompiler::~FlowGraphCompiler() {
   // BlockInfos are zone-allocated, so their destructors are not called.
   // Verify the labels explicitly here.
   for (int i = 0; i < block_info_.length(); ++i) {
     ASSERT(!block_info_[i]->label.IsLinked());
     ASSERT(!block_info_[i]->label.HasNear());
   }
 }
 
 
+bool FlowGraphCompiler::IsLeaf() const {
+  return is_dart_leaf_ &&
+         !parsed_function_.function().IsClosureFunction() &&
+         (parsed_function().copied_parameter_count() == 0);
+}
+
+
 void FlowGraphCompiler::InitCompiler() {
   pc_descriptors_list_ = new DescriptorList();
   exception_handlers_list_ = new ExceptionHandlerList();
   block_info_.Clear();
   for (int i = 0; i < block_order_.length(); ++i) {
     block_info_.Add(new BlockInfo());
   }
 }
 
 
@@ skipping 197 matching lines @@
 
 
 void FlowGraphCompiler::GenerateInstanceCall(
     intptr_t cid,
     intptr_t token_pos,
     intptr_t try_index,
     const String& function_name,
     intptr_t argument_count,
     const Array& argument_names,
     intptr_t checked_argument_count) {
+  ASSERT(!IsLeaf());
   ASSERT(frame_register_allocator()->IsSpilled());
   ICData& ic_data =
       ICData::ZoneHandle(ICData::New(parsed_function().function(),
                                      function_name,
                                      cid,
                                      checked_argument_count));
   const Array& arguments_descriptor =
       CodeGenerator::ArgumentsDescriptor(argument_count, argument_names);
   uword label_address = 0;
   switch (checked_argument_count) {
@@ skipping 320 matching lines @@
 
 
 void FrameRegisterAllocator::SpillInDeoptStub(DeoptimizationStub* stub) {
   for (int i = 0; i < stack_.length(); i++) {
     stub->Push(stack_[i]);
   }
 }
 
 
 }  // namespace dart