[crankshaft] Support inlining of function calls in tail position (in ES6 sense).

src/crankshaft/lithium.cc

 // Copyright 2012 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 "src/crankshaft/lithium.h"
 
 #include "src/ast/scopes.h"
 
 #if V8_TARGET_ARCH_IA32
 #include "src/crankshaft/ia32/lithium-ia32.h"  // NOLINT
@@ skipping 504 matching lines @@
   instr->set_environment(CreateEnvironment(
       hydrogen_env, &argument_index_accumulator, &objects_to_materialize));
   return instr;
 }
 
 LEnvironment* LChunkBuilderBase::CreateEnvironment(
     HEnvironment* hydrogen_env, int* argument_index_accumulator,
     ZoneList<HValue*>* objects_to_materialize) {
   if (hydrogen_env == NULL) return NULL;
 
+  BailoutId ast_id = hydrogen_env->ast_id();
+  DCHECK(!ast_id.IsNone() ||
+         (hydrogen_env->frame_type() != JS_FUNCTION &&
+          hydrogen_env->frame_type() != TAIL_CALLER_FUNCTION));
+
+  if (hydrogen_env->frame_type() == TAIL_CALLER_FUNCTION) {
+    // Skip potential outer arguments adaptor frame.
+    HEnvironment* outer_hydrogen_env = hydrogen_env->outer();
+    if (outer_hydrogen_env != nullptr &&
+        outer_hydrogen_env->frame_type() == ARGUMENTS_ADAPTOR) {
+      outer_hydrogen_env = outer_hydrogen_env->outer();
+    }
+    LEnvironment* outer = CreateEnvironment(
+        outer_hydrogen_env, argument_index_accumulator, objects_to_materialize);
+    return new (zone())
+        LEnvironment(hydrogen_env->closure(), hydrogen_env->frame_type(),
+                     ast_id, 0, 0, 0, outer, hydrogen_env->entry(), zone());
+  }
+
   LEnvironment* outer =
       CreateEnvironment(hydrogen_env->outer(), argument_index_accumulator,
                         objects_to_materialize);
-  BailoutId ast_id = hydrogen_env->ast_id();
-  DCHECK(!ast_id.IsNone() ||
-         hydrogen_env->frame_type() != JS_FUNCTION);
 
   int omitted_count = (hydrogen_env->frame_type() == JS_FUNCTION)
                           ? 0
                           : hydrogen_env->specials_count();
 
   int value_count = hydrogen_env->length() - omitted_count;
   LEnvironment* result =
       new(zone()) LEnvironment(hydrogen_env->closure(),
                                hydrogen_env->frame_type(),
                                ast_id,
@@ skipping 116 matching lines @@
 
 LPhase::~LPhase() {
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceLithium(name(), chunk_);
   }
 }
 
 
 }  // namespace internal
 }  // namespace v8