Add initial support for inlining.

src/compiler/js-inlining.cc

+// Copyright 2014 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/compiler/ast-graph-builder.h"
+#include "src/compiler/common-operator.h"
+#include "src/compiler/generic-node-inl.h"
+#include "src/compiler/graph-inl.h"
+#include "src/compiler/graph-visualizer.h"
+#include "src/compiler/js-inlining.h"
+#include "src/compiler/js-operator.h"
+#include "src/compiler/node-aux-data-inl.h"
+#include "src/compiler/node-matchers.h"
+#include "src/compiler/node-properties-inl.h"
+#include "src/compiler/simplified-operator.h"
+#include "src/compiler/typer.h"
+#include "src/parser.h"
+#include "src/rewriter.h"
+#include "src/scopes.h"
+
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+class InlinerVisitor : public NullNodeVisitor {
+ public:
+  explicit InlinerVisitor(JSInliner* inliner) : inliner_(inliner) {}
+
+  GenericGraphVisit::Control Post(Node* node) {
+    switch (node->opcode()) {
+      case IrOpcode::kJSCallFunction:
+        inliner_->TryInlineCall(node);
+        break;
+      default:
+        break;
+    }
+    return GenericGraphVisit::CONTINUE;
+  }
+
+ private:
+  JSInliner* inliner_;
+};
+
+
+void JSInliner::Inline() {
+  InlinerVisitor visitor(this);
+  jsgraph_->graph()->VisitNodeInputsFromEnd(&visitor);
+}
+
+
+static void MoveWithDependencies(Graph* graph, Node* node, Node* old_block,
+                                 Node* new_block) {
+  if (OperatorProperties::HasControlInput(node->op())) {
+    // Check if we have left the old_block.
+    if (NodeProperties::GetControlInput(node) != old_block) return;
+    // If not, move this node to the new_block.
+    NodeProperties::ReplaceControlInput(node, new_block);
+  }
+  // Independent of whether a node has a control input or not,
+  // it might have a dependency that is pinned to old_block.
+  for (InputIter iter = node->inputs().begin(); iter != node->inputs().end();
+       ++iter) {
+    if (NodeProperties::IsControlEdge(iter.edge())) continue;
+    MoveWithDependencies(graph, *iter, old_block, new_block);
+  }
+}
+
+
+static void MoveAllControlNodes(Node* from, Node* to) {
+  for (UseIter iter = from->uses().begin(); iter != from->uses().end();) {
+    if (NodeProperties::IsControlEdge(iter.edge())) {
+      iter.UpdateToAndIncrement(to);
+    } else {
+      ++iter;
+    }
+  }
+}
+
+
+// TODO(sigurds) Find a home for this function and reuse it everywhere (esp. in
+// test cases, where similar code is currently duplicated).
+static void Parse(Handle<JSFunction> function, CompilationInfoWithZone* info) {
+  CHECK(Parser::Parse(info));
+  StrictMode strict_mode = info->function()->strict_mode();
+  info->SetStrictMode(strict_mode);
+  info->SetOptimizing(BailoutId::None(), Handle<Code>(function->code()));
+  CHECK(Rewriter::Rewrite(info));
+  CHECK(Scope::Analyze(info));
+  CHECK_NE(NULL, info->scope());
+  Handle<ScopeInfo> scope_info = ScopeInfo::Create(info->scope(), info->zone());
+  info->shared_info()->set_scope_info(*scope_info);
+}
+
+
+// A facade on a JSFunction's graph to facilitate inlining. It assumes the
+// that the function graph has only one return statement, and provides
+// {UnifyReturn} to convert a function graph to that end.
+// InlineAtCall will create some new nodes using {graph}'s builders (and hence
+// those nodes will live in {graph}'s zone.
+class Inlinee {
+ public:
+  explicit Inlinee(JSGraph* graph) : jsgraph_(graph) {}
+
+  Graph* graph() { return jsgraph_->graph(); }
+  JSGraph* jsgraph() { return jsgraph_; }
+
+  // Returns the last regular control node, that is
+  // the last control node before the end node.
+  Node* end_block() { return NodeProperties::GetControlInput(unique_return()); }
+
+  // Return the effect output of the graph,
+  // that is the effect input of the return statement of the inlinee.
+  Node* effect_output() {
+    return NodeProperties::GetEffectInput(unique_return());
+  }
+  // Return the value output of the graph,
+  // that is the value input of the return statement of the inlinee.
+  Node* value_output() {
+    return NodeProperties::GetValueInput(unique_return(), 0);
+  }
+  // Return the unique return statement of the graph.
+  Node* unique_return() {
+    Node* unique_return =
+        NodeProperties::GetControlInput(jsgraph_->graph()->end());
+    DCHECK_EQ(IrOpcode::kReturn, unique_return->opcode());
+    return unique_return;
+  }
+  // Inline this graph at {call}, use {jsgraph} and its zone to create
+  // any new nodes.
+  void InlineAtCall(JSGraph* jsgraph, Node* call);
+  // Ensure that only a single return reaches the end node.
+  void UnifyReturn();
+
+ private:
+  JSGraph* jsgraph_;
+};
+
+
+void Inlinee::UnifyReturn() {
+  Graph* graph = jsgraph_->graph();
+
+  Node* final_merge = NodeProperties::GetControlInput(graph->end(), 0);
+  if (final_merge->opcode() == IrOpcode::kReturn) {
+    // nothing to do
+    return;
+  }
+  DCHECK_EQ(IrOpcode::kMerge, final_merge->opcode());
+
+  int predecessors =
+      OperatorProperties::GetControlInputCount(final_merge->op());
+  Operator* op_phi = jsgraph_->common()->Phi(predecessors);
+  Operator* op_ephi = jsgraph_->common()->EffectPhi(predecessors);
+
+  std::vector<Node*> values;
+  std::vector<Node*> effects;
+  // Iterate over all control flow predecessors,
+  // which must be return statements.
+  InputIter iter = final_merge->inputs().begin();
+  while (iter != final_merge->inputs().end()) {
+    Node* input = *iter;
+    switch (input->opcode()) {
+      case IrOpcode::kReturn:
+        values.push_back(NodeProperties::GetValueInput(input, 0));
+        effects.push_back(NodeProperties::GetEffectInput(input));
+        iter.UpdateToAndIncrement(NodeProperties::GetControlInput(input));
+        input->RemoveAllInputs();
+        break;
+      default:
+        UNREACHABLE();
+        ++iter;
+        break;
+    }
+  }
+  values.push_back(final_merge);
+  effects.push_back(final_merge);
+  Node* phi = graph->NewNode(op_phi, values.size(), values.data());
+  Node* ephi = graph->NewNode(op_ephi, effects.size(), effects.data());
+  Node* new_return =
+      graph->NewNode(jsgraph_->common()->Return(), phi, ephi, final_merge);
+  graph->end()->ReplaceInput(0, new_return);
+}
+
+
+void Inlinee::InlineAtCall(JSGraph* jsgraph, Node* call) {
+  MachineOperatorBuilder machine(jsgraph->zone());
+
+  Node* control = NodeProperties::GetControlInput(call);
+  // Move all the nodes to the end block.
+  MoveAllControlNodes(control, end_block());
+  // Now move the ones the call depends on back up.
+  // We have to do this back-and-forth to treat the case where the call is
+  // pinned to the start block.
+  MoveWithDependencies(graph(), call, end_block(), control);
+
+  // The inlinee uses the context from the JSFunction object. This will
+  // also be the effect dependency for the inlinee as it produces an effect.
+  // TODO(sigurds) Use simplified load once it is ready.
+  Node* context = jsgraph->graph()->NewNode(
+      machine.Load(kMachAnyTagged), NodeProperties::GetValueInput(call, 0),
+      jsgraph->Int32Constant(JSFunction::kContextOffset - kHeapObjectTag),
+      NodeProperties::GetEffectInput(call));
+
+  // {inlinee_inputs} counts JSFunction, Receiver, arguments, context,
+  // but not effect, control.
+  int inlinee_inputs = graph()->start()->op()->OutputCount();
+  // Context is last argument.
+  int inlinee_context_index = inlinee_inputs - 1;
+  // {inliner_inputs} counts JSFunction, Receiver, arguments, but not
+  // context, effect, control.
+  int inliner_inputs = OperatorProperties::GetValueInputCount(call->op());
+  // Iterate over all uses of the start node.
+  UseIter iter = graph()->start()->uses().begin();
+  while (iter != graph()->start()->uses().end()) {
+    Node* use = *iter;
+    switch (use->opcode()) {
+      case IrOpcode::kParameter: {
+        int index = 1 + static_cast<Operator1<int>*>(use->op())->parameter();
+        if (index < inliner_inputs && index < inlinee_context_index) {
+          // There is an input from the call, and the index is a value
+          // projection but not the context, so rewire the input.
+          NodeProperties::ReplaceWithValue(*iter, call->InputAt(index));
+        } else if (index == inlinee_context_index) {
+          // This is the context projection, rewire it to the context from the
+          // JSFunction object.
+          NodeProperties::ReplaceWithValue(*iter, context);
+        } else if (index < inlinee_context_index) {
+          // Call has fewer arguments than required, fill with undefined.
+          NodeProperties::ReplaceWithValue(*iter, jsgraph->UndefinedConstant());
+        } else {
+          // We got too many arguments, discard for now.
+          // TODO(sigurds): Fix to treat arguments array correctly.
+        }
+        ++iter;
+        break;
+      }
+      default:
+        if (NodeProperties::IsEffectEdge(iter.edge())) {
+          iter.UpdateToAndIncrement(context);
+        } else if (NodeProperties::IsControlEdge(iter.edge())) {
+          iter.UpdateToAndIncrement(control);
+        } else {
+          UNREACHABLE();
+        }
+        break;
+    }
+  }
+
+  // Iterate over all uses of the call node.
+  iter = call->uses().begin();
+  while (iter != call->uses().end()) {
+    if (NodeProperties::IsEffectEdge(iter.edge())) {
+      iter.UpdateToAndIncrement(effect_output());
+    } else if (NodeProperties::IsControlEdge(iter.edge())) {
+      UNREACHABLE();
+    } else {
+      DCHECK(NodeProperties::IsValueEdge(iter.edge()));
+      iter.UpdateToAndIncrement(value_output());
+    }
+  }
+  call->RemoveAllInputs();
+  DCHECK_EQ(0, call->UseCount());
+  // TODO(sigurds) Remove this once we copy.
+  unique_return()->RemoveAllInputs();
+}
+
+
+void JSInliner::TryInlineCall(Node* node) {
+  DCHECK_EQ(IrOpcode::kJSCallFunction, node->opcode());
+
+  ValueMatcher<Handle<JSFunction> > match(node->InputAt(0));
+  if (!match.HasValue()) {
+    return;
+  }
+
+  Handle<JSFunction> function = match.Value();
+
+  if (function->shared()->native()) {
+    if (FLAG_trace_turbo_inlining) {
+      SmartArrayPointer<char> name =
+          function->shared()->DebugName()->ToCString();
+      PrintF("Not Inlining %s into %s because inlinee is native\n", name.get(),
+             info_->shared_info()->DebugName()->ToCString().get());
+    }
+    return;
+  }
+
+  CompilationInfoWithZone info(function);
+  Parse(function, &info);
+
+  if (info.scope()->arguments() != NULL) {
+    // For now do not inline functions that use their arguments array.
+    SmartArrayPointer<char> name = function->shared()->DebugName()->ToCString();
+    if (FLAG_trace_turbo_inlining) {
+      PrintF(
+          "Not Inlining %s into %s because inlinee uses arguments "
+          "array\n",
+          name.get(), info_->shared_info()->DebugName()->ToCString().get());
+    }
+    return;
+  }
+
+  if (FLAG_trace_turbo_inlining) {
+    SmartArrayPointer<char> name = function->shared()->DebugName()->ToCString();
+    PrintF("Inlining %s into %s\n", name.get(),
+           info_->shared_info()->DebugName()->ToCString().get());
+  }
+
+  Graph graph(info_->zone());
+  graph.SetNextNodeId(jsgraph_->graph()->NextNodeID());
+
+  Typer typer(info_->zone());
+  CommonOperatorBuilder common(info_->zone());
+  JSGraph jsgraph(&graph, &common, &typer);
+
+  AstGraphBuilder graph_builder(&info, &jsgraph);
+  graph_builder.CreateGraph();
+
+  Inlinee inlinee(&jsgraph);
+  inlinee.UnifyReturn();
+  inlinee.InlineAtCall(jsgraph_, node);
+
+  jsgraph_->graph()->SetNextNodeId(inlinee.graph()->NextNodeID());
+}
+}
+}
+}  // namespace v8::internal::compiler