Reland r20974: Unify and simplify the FastCloneShallowArrayStub

src/code-stubs-hydrogen.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 "v8.h"
 
 #include "code-stubs.h"
 #include "hydrogen.h"
 #include "lithium.h"
 
@@ skipping 109 matching lines @@
   int param_count = descriptor_->register_param_count_;
   HEnvironment* start_environment = graph()->start_environment();
   HBasicBlock* next_block = CreateBasicBlock(start_environment);
   Goto(next_block);
   next_block->SetJoinId(BailoutId::StubEntry());
   set_current_block(next_block);
 
   bool runtime_stack_params = descriptor_->stack_parameter_count_.is_valid();
   HInstruction* stack_parameter_count = NULL;
   for (int i = 0; i < param_count; ++i) {
-    Representation r = descriptor_->IsParameterCountRegister(i)
-        ? Representation::Integer32()
-        : Representation::Tagged();
+    Representation r = descriptor_->register_param_representations_ == NULL
+        ? Representation::Tagged()
+        : descriptor_->register_param_representations_[i];
     HParameter* param = Add<HParameter>(i, HParameter::REGISTER_PARAMETER, r);
     start_environment->Bind(i, param);
     parameters_[i] = param;
     if (descriptor_->IsParameterCountRegister(i)) {
       param->set_type(HType::Smi());
       stack_parameter_count = param;
       arguments_length_ = stack_parameter_count;
     }
   }
 
@@ skipping 180 matching lines @@
 Handle<Code> NumberToStringStub::GenerateCode() {
   return DoGenerateCode(this);
 }
 
 
 template <>
 HValue* CodeStubGraphBuilder<FastCloneShallowArrayStub>::BuildCodeStub() {
   Factory* factory = isolate()->factory();
   HValue* undefined = graph()->GetConstantUndefined();
   AllocationSiteMode alloc_site_mode = casted_stub()->allocation_site_mode();
-  FastCloneShallowArrayStub::Mode mode = casted_stub()->mode();
-  int length = casted_stub()->length();
+
+  // This stub is very performance sensitive, the generated code must be tuned
+  // so that it doesn't build and eager frame.
+  info()->MarkMustNotHaveEagerFrame();
 
   HInstruction* allocation_site = Add<HLoadKeyed>(GetParameter(0),
                                                   GetParameter(1),
                                                   static_cast<HValue*>(NULL),
                                                   FAST_ELEMENTS);
   IfBuilder checker(this);
   checker.IfNot<HCompareObjectEqAndBranch, HValue*>(allocation_site,
                                                     undefined);
   checker.Then();
 
   HObjectAccess access = HObjectAccess::ForAllocationSiteOffset(
       AllocationSite::kTransitionInfoOffset);
   HInstruction* boilerplate = Add<HLoadNamedField>(
       allocation_site, static_cast<HValue*>(NULL), access);
-  HValue* push_value;
-  if (mode == FastCloneShallowArrayStub::CLONE_ANY_ELEMENTS) {
-    HValue* elements = AddLoadElements(boilerplate);
+  HValue* elements = AddLoadElements(boilerplate);
+  HValue* capacity = AddLoadFixedArrayLength(elements);
+  IfBuilder zero_capacity(this);
+  zero_capacity.If<HCompareNumericAndBranch>(capacity, graph()->GetConstant0(),
+                                           Token::EQ);
+  zero_capacity.Then();
+  Push(BuildCloneShallowArrayEmpty(boilerplate,
+                                   allocation_site,
+                                   alloc_site_mode));
+  zero_capacity.Else();
+  IfBuilder if_fixed_cow(this);
+  if_fixed_cow.If<HCompareMap>(elements, factory->fixed_cow_array_map());
+  if_fixed_cow.Then();
+  Push(BuildCloneShallowArrayCow(boilerplate,
+                                 allocation_site,
+                                 alloc_site_mode,
+                                 FAST_ELEMENTS));
+  if_fixed_cow.Else();
+  IfBuilder if_fixed(this);
+  if_fixed.If<HCompareMap>(elements, factory->fixed_array_map());
+  if_fixed.Then();
+  Push(BuildCloneShallowArrayNonEmpty(boilerplate,
+                                      allocation_site,
+                                      alloc_site_mode,
+                                      FAST_ELEMENTS));
 
-    IfBuilder if_fixed_cow(this);
-    if_fixed_cow.If<HCompareMap>(elements, factory->fixed_cow_array_map());
-    if_fixed_cow.Then();
-    push_value = BuildCloneShallowArray(boilerplate,
-                                        allocation_site,
-                                        alloc_site_mode,
-                                        FAST_ELEMENTS,
-                                        0/*copy-on-write*/);
-    environment()->Push(push_value);
-    if_fixed_cow.Else();
-
-    IfBuilder if_fixed(this);
-    if_fixed.If<HCompareMap>(elements, factory->fixed_array_map());
-    if_fixed.Then();
-    push_value = BuildCloneShallowArray(boilerplate,
-                                        allocation_site,
-                                        alloc_site_mode,
-                                        FAST_ELEMENTS,
-                                        length);
-    environment()->Push(push_value);
-    if_fixed.Else();
-    push_value = BuildCloneShallowArray(boilerplate,
-                                        allocation_site,
-                                        alloc_site_mode,
-                                        FAST_DOUBLE_ELEMENTS,
-                                        length);
-    environment()->Push(push_value);
-  } else {
-    ElementsKind elements_kind = casted_stub()->ComputeElementsKind();
-    push_value = BuildCloneShallowArray(boilerplate,
-                                        allocation_site,
-                                        alloc_site_mode,
-                                        elements_kind,
-                                        length);
-    environment()->Push(push_value);
-  }
+  if_fixed.Else();
+  Push(BuildCloneShallowArrayNonEmpty(boilerplate,
+                                      allocation_site,
+                                      alloc_site_mode,
+                                      FAST_DOUBLE_ELEMENTS));
+  if_fixed.End();
+  if_fixed_cow.End();
+  zero_capacity.End();
 
   checker.ElseDeopt("Uninitialized boilerplate literals");
   checker.End();
 
   return environment()->Pop();
 }
 
 
 Handle<Code> FastCloneShallowArrayStub::GenerateCode() {
   return DoGenerateCode(this);
@@ skipping 238 matching lines @@
     ElementsKind kind,
     AllocationSiteOverrideMode override_mode,
     ArgumentClass argument_class) {
   HValue* constructor = GetParameter(ArrayConstructorStubBase::kConstructor);
   HValue* alloc_site = GetParameter(ArrayConstructorStubBase::kAllocationSite);
   JSArrayBuilder array_builder(this, kind, alloc_site, constructor,
                                override_mode);
   HValue* result = NULL;
   switch (argument_class) {
     case NONE:
+      // This stub is very performance sensitive, the generated code must be
+      // tuned so that it doesn't build and eager frame.
+      info()->MarkMustNotHaveEagerFrame();
       result = array_builder.AllocateEmptyArray();
       break;
     case SINGLE:
       result = BuildArraySingleArgumentConstructor(&array_builder);
       break;
     case MULTIPLE:
       result = BuildArrayNArgumentsConstructor(&array_builder, kind);
       break;
   }
 
   return result;
 }
 
 
 HValue* CodeStubGraphBuilderBase::BuildInternalArrayConstructor(
     ElementsKind kind, ArgumentClass argument_class) {
   HValue* constructor = GetParameter(
       InternalArrayConstructorStubBase::kConstructor);
   JSArrayBuilder array_builder(this, kind, constructor);
 
   HValue* result = NULL;
   switch (argument_class) {
     case NONE:
+      // This stub is very performance sensitive, the generated code must be
+      // tuned so that it doesn't build and eager frame.
+      info()->MarkMustNotHaveEagerFrame();
       result = array_builder.AllocateEmptyArray();
       break;
     case SINGLE:
       result = BuildArraySingleArgumentConstructor(&array_builder);
       break;
     case MULTIPLE:
       result = BuildArrayNArgumentsConstructor(&array_builder, kind);
       break;
   }
   return result;
@@ skipping 804 matching lines @@
   return BuildRegExpConstructResult(length, index, input);
 }
 
 
 Handle<Code> RegExpConstructResultStub::GenerateCode() {
   return DoGenerateCode(this);
 }
 
 
 } }  // namespace v8::internal