Upgrade V8 to version 4.9.385.28

https://chromium.googlesource.com/v8/v8/+/4.9.385.28

FPIIM-449

Change-Id: I4b2e74289d4bf3667f2f3dc8aa2e541f63e26eb4
diff --git a/src/compiler/osr.cc b/src/compiler/osr.cc
new file mode 100644
index 0000000..55431c2
--- /dev/null
+++ b/src/compiler/osr.cc
@@ -0,0 +1,337 @@
+// 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/ast/scopes.h"
+#include "src/compiler.h"
+#include "src/compiler/all-nodes.h"
+#include "src/compiler/common-operator.h"
+#include "src/compiler/common-operator-reducer.h"
+#include "src/compiler/dead-code-elimination.h"
+#include "src/compiler/frame.h"
+#include "src/compiler/graph.h"
+#include "src/compiler/graph-reducer.h"
+#include "src/compiler/graph-trimmer.h"
+#include "src/compiler/graph-visualizer.h"
+#include "src/compiler/js-graph.h"
+#include "src/compiler/loop-analysis.h"
+#include "src/compiler/node.h"
+#include "src/compiler/node-marker.h"
+#include "src/compiler/osr.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+OsrHelper::OsrHelper(CompilationInfo* info)
+    : parameter_count_(info->scope()->num_parameters()),
+      stack_slot_count_(info->scope()->num_stack_slots() +
+                        info->osr_expr_stack_height()) {}
+
+
+#ifdef DEBUG
+#define TRACE_COND (FLAG_trace_turbo_graph && FLAG_trace_osr)
+#else
+#define TRACE_COND false
+#endif
+
+#define TRACE(...)                       \
+  do {                                   \
+    if (TRACE_COND) PrintF(__VA_ARGS__); \
+  } while (false)
+
+
+// Peel outer loops and rewire the graph so that control reduction can
+// produce a properly formed graph.
+static void PeelOuterLoopsForOsr(Graph* graph, CommonOperatorBuilder* common,
+                                 Zone* tmp_zone, Node* dead,
+                                 LoopTree* loop_tree, LoopTree::Loop* osr_loop,
+                                 Node* osr_normal_entry, Node* osr_loop_entry) {
+  const size_t original_count = graph->NodeCount();
+  AllNodes all(tmp_zone, graph);
+  NodeVector tmp_inputs(tmp_zone);
+  Node* sentinel = graph->NewNode(dead->op());
+
+  // Make a copy of the graph for each outer loop.
+  ZoneVector<NodeVector*> copies(tmp_zone);
+  for (LoopTree::Loop* loop = osr_loop->parent(); loop; loop = loop->parent()) {
+    void* stuff = tmp_zone->New(sizeof(NodeVector));
+    NodeVector* mapping =
+        new (stuff) NodeVector(original_count, sentinel, tmp_zone);
+    copies.push_back(mapping);
+    TRACE("OsrDuplication #%zu, depth %zu, header #%d:%s\n", copies.size(),
+          loop->depth(), loop_tree->HeaderNode(loop)->id(),
+          loop_tree->HeaderNode(loop)->op()->mnemonic());
+
+    // Prepare the mapping for OSR values and the OSR loop entry.
+    mapping->at(osr_normal_entry->id()) = dead;
+    mapping->at(osr_loop_entry->id()) = dead;
+
+    // The outer loops are dead in this copy.
+    for (LoopTree::Loop* outer = loop->parent(); outer;
+         outer = outer->parent()) {
+      for (Node* node : loop_tree->HeaderNodes(outer)) {
+        mapping->at(node->id()) = dead;
+        TRACE(" ---- #%d:%s -> dead (header)\n", node->id(),
+              node->op()->mnemonic());
+      }
+    }
+
+    // Copy all nodes.
+    for (size_t i = 0; i < all.live.size(); i++) {
+      Node* orig = all.live[i];
+      Node* copy = mapping->at(orig->id());
+      if (copy != sentinel) {
+        // Mapping already exists.
+        continue;
+      }
+      if (orig->InputCount() == 0 || orig->opcode() == IrOpcode::kParameter ||
+          orig->opcode() == IrOpcode::kOsrValue) {
+        // No need to copy leaf nodes or parameters.
+        mapping->at(orig->id()) = orig;
+        continue;
+      }
+
+      // Copy the node.
+      tmp_inputs.clear();
+      for (Node* input : orig->inputs()) {
+        tmp_inputs.push_back(mapping->at(input->id()));
+      }
+      copy = graph->NewNode(orig->op(), orig->InputCount(), &tmp_inputs[0]);
+      if (NodeProperties::IsTyped(orig)) {
+        NodeProperties::SetType(copy, NodeProperties::GetType(orig));
+      }
+      mapping->at(orig->id()) = copy;
+      TRACE(" copy #%d:%s -> #%d\n", orig->id(), orig->op()->mnemonic(),
+            copy->id());
+    }
+
+    // Fix missing inputs.
+    for (Node* orig : all.live) {
+      Node* copy = mapping->at(orig->id());
+      for (int j = 0; j < copy->InputCount(); j++) {
+        if (copy->InputAt(j) == sentinel) {
+          copy->ReplaceInput(j, mapping->at(orig->InputAt(j)->id()));
+        }
+      }
+    }
+
+    // Construct the entry into this loop from previous copies.
+
+    // Gather the live loop header nodes, {loop_header} first.
+    Node* loop_header = loop_tree->HeaderNode(loop);
+    NodeVector header_nodes(tmp_zone);
+    header_nodes.reserve(loop->HeaderSize());
+    header_nodes.push_back(loop_header);  // put the loop header first.
+    for (Node* node : loop_tree->HeaderNodes(loop)) {
+      if (node != loop_header && all.IsLive(node)) {
+        header_nodes.push_back(node);
+      }
+    }
+
+    // Gather backedges from the previous copies of the inner loops of {loop}.
+    NodeVectorVector backedges(tmp_zone);
+    TRACE("Gathering backedges...\n");
+    for (int i = 1; i < loop_header->InputCount(); i++) {
+      if (TRACE_COND) {
+        Node* control = loop_header->InputAt(i);
+        size_t incoming_depth = 0;
+        for (int j = 0; j < control->op()->ControlInputCount(); j++) {
+          Node* k = NodeProperties::GetControlInput(control, j);
+          incoming_depth =
+              std::max(incoming_depth, loop_tree->ContainingLoop(k)->depth());
+        }
+
+        TRACE(" edge @%d #%d:%s, incoming depth %zu\n", i, control->id(),
+              control->op()->mnemonic(), incoming_depth);
+      }
+
+      for (int pos = static_cast<int>(copies.size()) - 1; pos >= 0; pos--) {
+        backedges.push_back(NodeVector(tmp_zone));
+        backedges.back().reserve(header_nodes.size());
+
+        NodeVector* previous_map = pos > 0 ? copies[pos - 1] : nullptr;
+
+        for (Node* node : header_nodes) {
+          Node* input = node->InputAt(i);
+          if (previous_map) input = previous_map->at(input->id());
+          backedges.back().push_back(input);
+          TRACE("   node #%d:%s(@%d) = #%d:%s\n", node->id(),
+                node->op()->mnemonic(), i, input->id(),
+                input->op()->mnemonic());
+        }
+      }
+    }
+
+    int backedge_count = static_cast<int>(backedges.size());
+    if (backedge_count == 1) {
+      // Simple case of single backedge, therefore a single entry.
+      int index = 0;
+      for (Node* node : header_nodes) {
+        Node* copy = mapping->at(node->id());
+        Node* input = backedges[0][index];
+        copy->ReplaceInput(0, input);
+        TRACE(" header #%d:%s(0) => #%d:%s\n", copy->id(),
+              copy->op()->mnemonic(), input->id(), input->op()->mnemonic());
+        index++;
+      }
+    } else {
+      // Complex case of multiple backedges from previous copies requires
+      // merging the backedges to create the entry into the loop header.
+      Node* merge = nullptr;
+      int index = 0;
+      for (Node* node : header_nodes) {
+        // Gather edge inputs into {tmp_inputs}.
+        tmp_inputs.clear();
+        for (int edge = 0; edge < backedge_count; edge++) {
+          tmp_inputs.push_back(backedges[edge][index]);
+        }
+        Node* copy = mapping->at(node->id());
+        Node* input;
+        if (node == loop_header) {
+          // Create the merge for the entry into the loop header.
+          input = merge = graph->NewNode(common->Merge(backedge_count),
+                                         backedge_count, &tmp_inputs[0]);
+          copy->ReplaceInput(0, merge);
+        } else {
+          // Create a phi that merges values at entry into the loop header.
+          DCHECK_NOT_NULL(merge);
+          DCHECK(IrOpcode::IsPhiOpcode(node->opcode()));
+          tmp_inputs.push_back(merge);
+          Node* phi = input = graph->NewNode(
+              common->ResizeMergeOrPhi(node->op(), backedge_count),
+              backedge_count + 1, &tmp_inputs[0]);
+          copy->ReplaceInput(0, phi);
+        }
+
+        // Print the merge.
+        if (TRACE_COND) {
+          TRACE(" header #%d:%s(0) => #%d:%s(", copy->id(),
+                copy->op()->mnemonic(), input->id(), input->op()->mnemonic());
+          for (size_t i = 0; i < tmp_inputs.size(); i++) {
+            if (i > 0) TRACE(", ");
+            Node* input = tmp_inputs[i];
+            TRACE("#%d:%s", input->id(), input->op()->mnemonic());
+          }
+          TRACE(")\n");
+        }
+
+        index++;
+      }
+    }
+  }
+
+  // Kill the outer loops in the original graph.
+  TRACE("Killing outer loop headers...\n");
+  for (LoopTree::Loop* outer = osr_loop->parent(); outer;
+       outer = outer->parent()) {
+    Node* loop_header = loop_tree->HeaderNode(outer);
+    loop_header->ReplaceUses(dead);
+    TRACE(" ---- #%d:%s\n", loop_header->id(), loop_header->op()->mnemonic());
+  }
+
+  // Merge the ends of the graph copies.
+  Node* const end = graph->end();
+  int const input_count = end->InputCount();
+  for (int i = 0; i < input_count; ++i) {
+    NodeId const id = end->InputAt(i)->id();
+    for (NodeVector* const copy : copies) {
+      end->AppendInput(graph->zone(), copy->at(id));
+      NodeProperties::ChangeOp(end, common->End(end->InputCount()));
+    }
+  }
+
+  if (FLAG_trace_turbo_graph) {  // Simple textual RPO.
+    OFStream os(stdout);
+    os << "-- Graph after OSR duplication -- " << std::endl;
+    os << AsRPO(*graph);
+  }
+}
+
+
+void OsrHelper::Deconstruct(JSGraph* jsgraph, CommonOperatorBuilder* common,
+                            Zone* tmp_zone) {
+  Graph* graph = jsgraph->graph();
+  Node* osr_normal_entry = nullptr;
+  Node* osr_loop_entry = nullptr;
+  Node* osr_loop = nullptr;
+
+  for (Node* node : graph->start()->uses()) {
+    if (node->opcode() == IrOpcode::kOsrLoopEntry) {
+      osr_loop_entry = node;  // found the OSR loop entry
+    } else if (node->opcode() == IrOpcode::kOsrNormalEntry) {
+      osr_normal_entry = node;
+    }
+  }
+
+  if (osr_loop_entry == nullptr) {
+    // No OSR entry found, do nothing.
+    CHECK(osr_normal_entry);
+    return;
+  }
+
+  for (Node* use : osr_loop_entry->uses()) {
+    if (use->opcode() == IrOpcode::kLoop) {
+      CHECK(!osr_loop);             // should be only one OSR loop.
+      osr_loop = use;               // found the OSR loop.
+    }
+  }
+
+  CHECK(osr_loop);  // Should have found the OSR loop.
+
+  // Analyze the graph to determine how deeply nested the OSR loop is.
+  LoopTree* loop_tree = LoopFinder::BuildLoopTree(graph, tmp_zone);
+
+  Node* dead = jsgraph->Dead();
+  LoopTree::Loop* loop = loop_tree->ContainingLoop(osr_loop);
+  if (loop->depth() > 0) {
+    PeelOuterLoopsForOsr(graph, common, tmp_zone, dead, loop_tree, loop,
+                         osr_normal_entry, osr_loop_entry);
+  }
+
+  // Replace the normal entry with {Dead} and the loop entry with {Start}
+  // and run the control reducer to clean up the graph.
+  osr_normal_entry->ReplaceUses(dead);
+  osr_normal_entry->Kill();
+  osr_loop_entry->ReplaceUses(graph->start());
+  osr_loop_entry->Kill();
+
+  // Remove the first input to the {osr_loop}.
+  int const live_input_count = osr_loop->InputCount() - 1;
+  CHECK_NE(0, live_input_count);
+  for (Node* const use : osr_loop->uses()) {
+    if (NodeProperties::IsPhi(use)) {
+      use->RemoveInput(0);
+      NodeProperties::ChangeOp(
+          use, common->ResizeMergeOrPhi(use->op(), live_input_count));
+    }
+  }
+  osr_loop->RemoveInput(0);
+  NodeProperties::ChangeOp(
+      osr_loop, common->ResizeMergeOrPhi(osr_loop->op(), live_input_count));
+
+  // Run control reduction and graph trimming.
+  // TODO(bmeurer): The OSR deconstruction could be a regular reducer and play
+  // nice together with the rest, instead of having this custom stuff here.
+  GraphReducer graph_reducer(tmp_zone, graph);
+  DeadCodeElimination dce(&graph_reducer, graph, common);
+  CommonOperatorReducer cor(&graph_reducer, graph, common, jsgraph->machine());
+  graph_reducer.AddReducer(&dce);
+  graph_reducer.AddReducer(&cor);
+  graph_reducer.ReduceGraph();
+  GraphTrimmer trimmer(tmp_zone, graph);
+  NodeVector roots(tmp_zone);
+  jsgraph->GetCachedNodes(&roots);
+  trimmer.TrimGraph(roots.begin(), roots.end());
+}
+
+
+void OsrHelper::SetupFrame(Frame* frame) {
+  // The optimized frame will subsume the unoptimized frame. Do so by reserving
+  // the first spill slots.
+  frame->ReserveSpillSlots(UnoptimizedFrameSlots());
+}
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8