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

runtime/vm/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/compiler.h"
 
 #include "vm/assembler.h"
 #include "vm/ast_printer.h"
 #include "vm/code_generator.h"
 #include "vm/code_patcher.h"
@@ skipping 192 matching lines @@
                                        graph_builder.current_ssa_temp_index());
           allocator.ResolveConstraints();
           allocator.AnalyzeLiveness();
 
           // Temporary bailout until we support code generation from SSA form.
           graph_builder.Bailout("No SSA code generation support.");
         }
       }
     }
 
+    bool is_leaf = false;
+    if (optimized) {
+      FlowGraphAnalyzer analyzer(block_order);
+      analyzer.Analyze();
+      is_leaf = analyzer.is_leaf();
+    }
     Assembler assembler;
     FlowGraphCompiler graph_compiler(&assembler, parsed_function,
-                                     block_order, optimized);
+                                     block_order, optimized, is_leaf);
     {
       TimerScope timer(FLAG_compiler_stats,
                        &CompilerStats::graphcompiler_timer,
                        isolate);
       graph_compiler.CompileGraph();
     }
     {
       TimerScope timer(FLAG_compiler_stats,
                        &CompilerStats::codefinalizer_timer,
                        isolate);
@@ skipping 356 matching lines @@
     isolate->object_store()->clear_sticky_error();
     isolate->set_long_jump_base(base);
     return result.raw();
   }
   UNREACHABLE();
   return Object::null();
 }
 
 
 }  // namespace dart