[compiler] Extend the functionality of CodeStubAssembler

src/compiler/code-stub-assembler.cc

Index: src/compiler/code-stub-assembler.cc
diff --git a/src/compiler/code-stub-assembler.cc b/src/compiler/code-stub-assembler.cc
index 702b12ad127776cfd0b59cd6ecaf2e5a1e74b580..8bbf1a6f42ba48635e1345490897c70e994ddd9c 100644
--- a/src/compiler/code-stub-assembler.cc
+++ b/src/compiler/code-stub-assembler.cc
@@ -24,7 +24,6 @@ namespace v8 {
 namespace internal {
 namespace compiler {
 
-
 CodeStubAssembler::CodeStubAssembler(Isolate* isolate, Zone* zone,
                                      const CallInterfaceDescriptor& descriptor,
                                      Code::Flags flags, const char* name)
@@ -34,8 +33,8 @@ CodeStubAssembler::CodeStubAssembler(Isolate* isolate, Zone* zone,
                                          CallDescriptor::kNoFlags))),
       flags_(flags),
       name_(name),
-      code_generated_(false) {}
-
+      code_generated_(false),
+      variables_(zone) {}
 
 CodeStubAssembler::~CodeStubAssembler() {}
 
@@ -77,6 +76,9 @@ Node* CodeStubAssembler::BooleanConstant(bool value) {
   return raw_assembler_->BooleanConstant(value);
 }
 
+Node* CodeStubAssembler::ExternalConstant(ExternalReference address) {
+  return raw_assembler_->ExternalConstant(address);
+}
 
 Node* CodeStubAssembler::Parameter(int value) {
   return raw_assembler_->Parameter(value);
@@ -87,6 +89,13 @@ void CodeStubAssembler::Return(Node* value) {
   return raw_assembler_->Return(value);
 }
 
+void CodeStubAssembler::Bind(CodeStubAssembler::Label* label) {
+  return label->Bind();
+}
+
+Node* CodeStubAssembler::LoadFramePointer() {
+  return raw_assembler_->LoadFramePointer();
+}
 
 Node* CodeStubAssembler::SmiShiftBitsConstant() {
   return Int32Constant(kSmiShiftSize + kSmiTagSize);
@@ -102,27 +111,73 @@ Node* CodeStubAssembler::SmiUntag(Node* value) {
   return raw_assembler_->WordSar(value, SmiShiftBitsConstant());
 }
 
+#define DEFINE_CODE_STUB_ASSEMBER_BINARY_OP(name)   \
+  Node* CodeStubAssembler::name(Node* a, Node* b) { \
+    return raw_assembler_->name(a, b);              \
+  }
+CODE_STUB_ASSEMBLER_BINARY_OP_LIST(DEFINE_CODE_STUB_ASSEMBER_BINARY_OP)
+#undef DEFINE_CODE_STUB_ASSEMBER_BINARY_OP
 
-Node* CodeStubAssembler::IntPtrAdd(Node* a, Node* b) {
-  return raw_assembler_->IntPtrAdd(a, b);
+Node* CodeStubAssembler::WordShl(Node* value, int shift) {
+  return raw_assembler_->WordShl(value, Int32Constant(shift));
 }
 
-
-Node* CodeStubAssembler::IntPtrSub(Node* a, Node* b) {
-  return raw_assembler_->IntPtrSub(a, b);
+Node* CodeStubAssembler::WordIsSmi(Node* a) {
+  return WordEqual(raw_assembler_->WordAnd(a, Int32Constant(kSmiTagMask)),
+                   Int32Constant(0));
 }
 
-
-Node* CodeStubAssembler::WordShl(Node* value, int shift) {
-  return raw_assembler_->WordShl(value, Int32Constant(shift));
+Node* CodeStubAssembler::LoadBufferObject(Node* buffer, int offset) {
+  return raw_assembler_->Load(MachineType::AnyTagged(), buffer,
+                              IntPtrConstant(offset));
 }
 
-
 Node* CodeStubAssembler::LoadObjectField(Node* object, int offset) {
   return raw_assembler_->Load(MachineType::AnyTagged(), object,
                               IntPtrConstant(offset - kHeapObjectTag));
 }
 
+Node* CodeStubAssembler::LoadFixedArrayElementSmiIndex(Node* object,
+                                                       Node* smi_index,
+                                                       int additional_offset) {
+  Node* header_size = raw_assembler_->Int32Constant(
+      additional_offset + FixedArray::kHeaderSize - kHeapObjectTag);
+  Node* scaled_index =
+      (kSmiShiftSize == 0)
+          ? raw_assembler_->Word32Shl(
+                smi_index, Int32Constant(kPointerSizeLog2 - kSmiTagSize))
+          : raw_assembler_->Word32Shl(SmiUntag(smi_index),
+                                      Int32Constant(kPointerSizeLog2));
+  Node* offset = raw_assembler_->Int32Add(scaled_index, header_size);
+  return raw_assembler_->Load(MachineType::AnyTagged(), object, offset);
+}
+
+Node* CodeStubAssembler::LoadFixedArrayElementConstantIndex(Node* object,
+                                                            int index) {
+  Node* offset = raw_assembler_->Int32Constant(
+      FixedArray::kHeaderSize - kHeapObjectTag + index * kPointerSize);
+  return raw_assembler_->Load(MachineType::AnyTagged(), object, offset);
+}
+
+Node* CodeStubAssembler::LoadRoot(Heap::RootListIndex root_index) {
+  if (isolate()->heap()->RootCanBeTreatedAsConstant(root_index)) {
+    Handle<Object> root = isolate()->heap()->root_handle(root_index);
+    if (root->IsSmi()) {
+      return Int32Constant(Handle<Smi>::cast(root)->value());
+    } else {
+      return HeapConstant(Handle<HeapObject>::cast(root));
+    }
+  }
+
+  compiler::Node* roots_array_start =
+      ExternalConstant(ExternalReference::roots_array_start(isolate()));
+  USE(roots_array_start);
+
+  // TODO(danno): Implement thee root-access case where the root is not constant
+  // and must be loaded from the root array.
+  UNIMPLEMENTED();
+  return nullptr;
+}
 
 Node* CodeStubAssembler::CallN(CallDescriptor* descriptor, Node* code_target,
                                Node** args) {
@@ -147,19 +202,77 @@ Node* CodeStubAssembler::CallRuntime(Runtime::FunctionId function_id,
   return raw_assembler_->CallRuntime2(function_id, arg1, arg2, context);
 }
 
-
 Node* CodeStubAssembler::TailCallRuntime(Runtime::FunctionId function_id,
                                          Node* context, Node* arg1) {
   return raw_assembler_->TailCallRuntime1(function_id, arg1, context);
 }
 
-
 Node* CodeStubAssembler::TailCallRuntime(Runtime::FunctionId function_id,
                                          Node* context, Node* arg1,
                                          Node* arg2) {
   return raw_assembler_->TailCallRuntime2(function_id, arg1, arg2, context);
 }
 
+Node* CodeStubAssembler::TailCallRuntime(Runtime::FunctionId function_id,
+                                         Node* context, Node* arg1, Node* arg2,
+                                         Node* arg3) {
+  return raw_assembler_->TailCallRuntime3(function_id, arg1, arg2, arg3,
+                                          context);
+}
+
+Node* CodeStubAssembler::TailCallRuntime(Runtime::FunctionId function_id,
+                                         Node* context, Node* arg1, Node* arg2,
+                                         Node* arg3, Node* arg4) {
+  return raw_assembler_->TailCallRuntime4(function_id, arg1, arg2, arg3, arg4,
+                                          context);
+}
+
+Node* CodeStubAssembler::TailCallStub(CodeStub& stub, Node** args) {
+  Node* code_target = HeapConstant(stub.GetCode());
+  CallDescriptor* descriptor = Linkage::GetStubCallDescriptor(
+      isolate(), zone(), stub.GetCallInterfaceDescriptor(),
+      stub.GetStackParameterCount(), CallDescriptor::kSupportsTailCalls);
+  return raw_assembler_->TailCallN(descriptor, code_target, args);
+}
+
+Node* CodeStubAssembler::TailCall(
+    const CallInterfaceDescriptor& interface_descriptor, Node* code_target,
+    Node** args) {
+  CallDescriptor* descriptor = Linkage::GetStubCallDescriptor(
+      isolate(), zone(), interface_descriptor,
+      interface_descriptor.GetStackParameterCount(),
+      CallDescriptor::kSupportsTailCalls);
+  return raw_assembler_->TailCallN(descriptor, code_target, args);
+}
+
+void CodeStubAssembler::Goto(CodeStubAssembler::Label* label) {
+  label->MergeVariables();
+  raw_assembler_->Goto(label->label_);
+}
+
+void CodeStubAssembler::Branch(Node* condition,
+                               CodeStubAssembler::Label* true_label,
+                               CodeStubAssembler::Label* false_label) {
+  true_label->MergeVariables();
+  false_label->MergeVariables();
+  return raw_assembler_->Branch(condition, true_label->label_,
+                                false_label->label_);
+}
+
+void CodeStubAssembler::Switch(Node* index, Label* default_label,
+                               int32_t* case_values, Label** case_labels,
+                               size_t case_count) {
+  RawMachineLabel** labels =
+      new (zone()->New(sizeof(RawMachineLabel*) * case_count))
+          RawMachineLabel*[case_count];
+  for (size_t i = 0; i < case_count; ++i) {
+    labels[i] = case_labels[i]->label_;
+    case_labels[i]->MergeVariables();
+    default_label->MergeVariables();
+  }
+  return raw_assembler_->Switch(index, default_label->label_, case_values,
+                                labels, case_count);
+}
 
 // RawMachineAssembler delegate helpers:
 Isolate* CodeStubAssembler::isolate() { return raw_assembler_->isolate(); }
@@ -170,6 +283,159 @@ Graph* CodeStubAssembler::graph() { return raw_assembler_->graph(); }
 
 Zone* CodeStubAssembler::zone() { return raw_assembler_->zone(); }
 
+// The core implementation of Variable is stored through an indirection so
+// that it can outlive the often block-scoped Variable declarations. This is
+// needed to ensure that variable binding and merging through phis can
+// properly be verified.
+class CodeStubAssembler::Variable::Impl : public ZoneObject {
+ public:
+  explicit Impl(MachineRepresentation rep) : value_(nullptr), rep_(rep) {}
+  Node* value_;
+  MachineRepresentation rep_;
+};
+
+CodeStubAssembler::Variable::Variable(CodeStubAssembler* assembler,
+                                      MachineRepresentation rep)
+    : impl_(new (assembler->zone()) Impl(rep)) {
+  assembler->variables_.push_back(impl_);
+}
+
+void CodeStubAssembler::Variable::Bind(Node* value) { impl_->value_ = value; }
+
+Node* CodeStubAssembler::Variable::value() const {
+  DCHECK_NOT_NULL(impl_->value_);
+  return impl_->value_;
+}
+
+MachineRepresentation CodeStubAssembler::Variable::rep() const {
+  return impl_->rep_;
+}
+
+bool CodeStubAssembler::Variable::IsBound() const {
+  return impl_->value_ != nullptr;
+}
+
+CodeStubAssembler::Label::Label(CodeStubAssembler* assembler)
+    : bound_(false), merge_count_(0), assembler_(assembler), label_(nullptr) {
+  void* buffer = assembler->zone()->New(sizeof(RawMachineLabel));
+  label_ = new (buffer) RawMachineLabel();
+}
+
+CodeStubAssembler::Label::Label(CodeStubAssembler* assembler,
+                                int merged_value_count,
+                                CodeStubAssembler::Variable** merged_variables)
+    : bound_(false), merge_count_(0), assembler_(assembler), label_(nullptr) {
+  void* buffer = assembler->zone()->New(sizeof(RawMachineLabel));
+  label_ = new (buffer) RawMachineLabel();
+  for (int i = 0; i < merged_value_count; ++i) {
+    variable_phis_[merged_variables[i]->impl_] = nullptr;
+  }
+}
+
+CodeStubAssembler::Label::Label(CodeStubAssembler* assembler,
+                                CodeStubAssembler::Variable* merged_variable)
+    : CodeStubAssembler::Label(assembler, 1, &merged_variable) {}
+
+void CodeStubAssembler::Label::MergeVariables() {
+  ++merge_count_;
+  for (auto var : assembler_->variables_) {
+    size_t count = 0;
+    Node* node = var->value_;
+    if (node != nullptr) {
+      auto i = variable_merges_.find(var);
+      if (i != variable_merges_.end()) {
+        i->second.push_back(node);
+        count = i->second.size();
+      } else {
+        count = 1;
+        variable_merges_[var] = std::vector<Node*>(1, node);
+      }
+    }
+    // If the following asserts, then you've jumped to a label without a bound
+    // variable along that path that expects to merge its value into a phi.
+    DCHECK(variable_phis_.find(var) == variable_phis_.end() ||
+           count == merge_count_);
+    USE(count);
+
+    // If the label is already bound, we already know the set of variables to
+    // merge and phi nodes have already been created.
+    if (bound_) {
+      auto phi = variable_phis_.find(var);
+      if (phi != variable_phis_.end()) {
+        DCHECK_NOT_NULL(phi->second);
+        assembler_->raw_assembler_->AppendPhiInput(phi->second, node);
+      } else {
+        auto i = variable_merges_.find(var);
+        USE(i);
+        // If the following assert fires, then you've declared a variable that
+        // has the same bound value along all paths up until the point you bound
+        // this label, but then later merged a path with a new value for the
+        // variable after the label bind (it's not possible to add phis to the
+        // bound label after the fact, just make sure to list the variable in
+        // the label's constructor's list of merged variables).
+        DCHECK(find_if(i->second.begin(), i->second.end(),
+                       [node](Node* e) -> bool { return node != e; }) ==
+               i->second.end());
+      }
+    }
+  }
+}
+
+void CodeStubAssembler::Label::Bind() {
+  DCHECK(!bound_);
+  assembler_->raw_assembler_->Bind(label_);
+
+  // Make sure that all variables that have changed along any path up to this
+  // point are marked as merge variables.
+  for (auto var : assembler_->variables_) {
+    Node* shared_value = nullptr;
+    auto i = variable_merges_.find(var);
+    if (i != variable_merges_.end()) {
+      for (auto value : i->second) {
+        DCHECK(value != nullptr);
+        if (value != shared_value) {
+          if (shared_value == nullptr) {
+            shared_value = value;
+          } else {
+            variable_phis_[var] = nullptr;
+          }
+        }
+      }
+    }
+  }
+
+  for (auto var : variable_phis_) {
+    CodeStubAssembler::Variable::Impl* var_impl = var.first;
+    auto i = variable_merges_.find(var_impl);
+    // If the following assert fires, then a variable that has been marked as
+    // being merged at the label--either by explicitly marking it so in the
+    // label constructor or by having seen different bound values at branches
+    // into the label--doesn't have a bound value along all of the paths that
+    // have been merged into the label up to this point.
+    DCHECK(i != variable_merges_.end() && i->second.size() == merge_count_);
+    Node* phi = assembler_->raw_assembler_->Phi(
+        var.first->rep_, static_cast<int>(merge_count_), &(i->second[0]));
+    variable_phis_[var_impl] = phi;
+  }
+
+  // Bind all variables to a merge phi, the common value along all paths or
+  // null.
+  for (auto var : assembler_->variables_) {
+    auto i = variable_phis_.find(var);
+    if (i != variable_phis_.end()) {
+      var->value_ = i->second;
+    } else {
+      auto j = variable_merges_.find(var);
+      if (j != variable_merges_.end() && j->second.size() == merge_count_) {
+        var->value_ = j->second.back();
+      } else {
+        var->value_ = nullptr;
+      }
+    }
+  }
+
+  bound_ = true;
+}
 
 }  // namespace compiler
 }  // namespace internal