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/bytecode-branch-analysis.cc b/src/compiler/bytecode-branch-analysis.cc
new file mode 100644
index 0000000..27699a1
--- /dev/null
+++ b/src/compiler/bytecode-branch-analysis.cc
@@ -0,0 +1,125 @@
+// Copyright 2015 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/bytecode-branch-analysis.h"
+
+#include "src/interpreter/bytecode-array-iterator.h"
+#include "src/objects-inl.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+// The class contains all of the sites that contain
+// branches to a particular target (bytecode offset).
+class BytecodeBranchInfo final : public ZoneObject {
+ public:
+ explicit BytecodeBranchInfo(Zone* zone)
+ : back_edge_offsets_(zone), fore_edge_offsets_(zone) {}
+
+ void AddBranch(int source_offset, int target_offset);
+
+ // The offsets of bytecodes that refer to this bytecode as
+ // a back-edge predecessor.
+ const ZoneVector<int>* back_edge_offsets() { return &back_edge_offsets_; }
+
+ // The offsets of bytecodes that refer to this bytecode as
+ // a forwards-edge predecessor.
+ const ZoneVector<int>* fore_edge_offsets() { return &fore_edge_offsets_; }
+
+ private:
+ ZoneVector<int> back_edge_offsets_;
+ ZoneVector<int> fore_edge_offsets_;
+
+ DISALLOW_COPY_AND_ASSIGN(BytecodeBranchInfo);
+};
+
+
+void BytecodeBranchInfo::AddBranch(int source_offset, int target_offset) {
+ if (source_offset < target_offset) {
+ fore_edge_offsets_.push_back(source_offset);
+ } else {
+ back_edge_offsets_.push_back(source_offset);
+ }
+}
+
+
+BytecodeBranchAnalysis::BytecodeBranchAnalysis(
+ Handle<BytecodeArray> bytecode_array, Zone* zone)
+ : branch_infos_(zone),
+ bytecode_array_(bytecode_array),
+ reachable_(bytecode_array->length(), zone),
+ zone_(zone) {}
+
+
+void BytecodeBranchAnalysis::Analyze() {
+ interpreter::BytecodeArrayIterator iterator(bytecode_array());
+ bool reachable = true;
+ while (!iterator.done()) {
+ interpreter::Bytecode bytecode = iterator.current_bytecode();
+ int current_offset = iterator.current_offset();
+ // All bytecode basic blocks are generated to be forward reachable
+ // and may also be backward reachable. Hence if there's a forward
+ // branch targetting here the code becomes reachable.
+ reachable = reachable || forward_branches_target(current_offset);
+ if (reachable) {
+ reachable_.Add(current_offset);
+ if (interpreter::Bytecodes::IsConditionalJump(bytecode)) {
+ // Only the branch is recorded, the forward path falls through
+ // and is handled as normal bytecode data flow.
+ AddBranch(current_offset, iterator.GetJumpTargetOffset());
+ } else if (interpreter::Bytecodes::IsJump(bytecode)) {
+ // Unless the branch targets the next bytecode it's not
+ // reachable. If it targets the next bytecode the check at the
+ // start of the loop will set the reachable flag.
+ AddBranch(current_offset, iterator.GetJumpTargetOffset());
+ reachable = false;
+ } else if (interpreter::Bytecodes::IsJumpOrReturn(bytecode)) {
+ DCHECK_EQ(bytecode, interpreter::Bytecode::kReturn);
+ reachable = false;
+ }
+ }
+ iterator.Advance();
+ }
+}
+
+
+const ZoneVector<int>* BytecodeBranchAnalysis::BackwardBranchesTargetting(
+ int offset) const {
+ auto iterator = branch_infos_.find(offset);
+ if (branch_infos_.end() != iterator) {
+ return iterator->second->back_edge_offsets();
+ } else {
+ return nullptr;
+ }
+}
+
+
+const ZoneVector<int>* BytecodeBranchAnalysis::ForwardBranchesTargetting(
+ int offset) const {
+ auto iterator = branch_infos_.find(offset);
+ if (branch_infos_.end() != iterator) {
+ return iterator->second->fore_edge_offsets();
+ } else {
+ return nullptr;
+ }
+}
+
+
+void BytecodeBranchAnalysis::AddBranch(int source_offset, int target_offset) {
+ BytecodeBranchInfo* branch_info = nullptr;
+ auto iterator = branch_infos_.find(target_offset);
+ if (branch_infos_.end() == iterator) {
+ branch_info = new (zone()) BytecodeBranchInfo(zone());
+ branch_infos_.insert(std::make_pair(target_offset, branch_info));
+ } else {
+ branch_info = iterator->second;
+ }
+ branch_info->AddBranch(source_offset, target_offset);
+}
+
+
+} // namespace compiler
+} // namespace internal
+} // namespace v8