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/frame-elider.cc b/src/compiler/frame-elider.cc
new file mode 100644
index 0000000..7c3f9b2
--- /dev/null
+++ b/src/compiler/frame-elider.cc
@@ -0,0 +1,131 @@
+// 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/base/adapters.h"
+#include "src/compiler/frame-elider.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+FrameElider::FrameElider(InstructionSequence* code) : code_(code) {}
+
+void FrameElider::Run() {
+ MarkBlocks();
+ PropagateMarks();
+ MarkDeConstruction();
+}
+
+
+void FrameElider::MarkBlocks() {
+ for (auto block : instruction_blocks()) {
+ if (block->needs_frame()) continue;
+ for (auto i = block->code_start(); i < block->code_end(); ++i) {
+ if (InstructionAt(i)->IsCall() ||
+ InstructionAt(i)->opcode() == ArchOpcode::kArchDeoptimize) {
+ block->mark_needs_frame();
+ break;
+ }
+ }
+ }
+}
+
+
+void FrameElider::PropagateMarks() {
+ while (PropagateInOrder() && PropagateReversed()) {
+ }
+}
+
+
+void FrameElider::MarkDeConstruction() {
+ for (auto block : instruction_blocks()) {
+ if (block->needs_frame()) {
+ // Special case: The start block needs a frame.
+ if (block->predecessors().empty()) {
+ block->mark_must_construct_frame();
+ }
+ // Find "frame -> no frame" transitions, inserting frame
+ // deconstructions.
+ for (auto succ : block->successors()) {
+ if (!InstructionBlockAt(succ)->needs_frame()) {
+ DCHECK_EQ(1U, block->SuccessorCount());
+ block->mark_must_deconstruct_frame();
+ }
+ }
+ } else {
+ // Find "no frame -> frame" transitions, inserting frame constructions.
+ for (auto succ : block->successors()) {
+ if (InstructionBlockAt(succ)->needs_frame()) {
+ DCHECK_NE(1U, block->SuccessorCount());
+ InstructionBlockAt(succ)->mark_must_construct_frame();
+ }
+ }
+ }
+ }
+}
+
+
+bool FrameElider::PropagateInOrder() {
+ bool changed = false;
+ for (auto block : instruction_blocks()) {
+ changed |= PropagateIntoBlock(block);
+ }
+ return changed;
+}
+
+
+bool FrameElider::PropagateReversed() {
+ bool changed = false;
+ for (auto block : base::Reversed(instruction_blocks())) {
+ changed |= PropagateIntoBlock(block);
+ }
+ return changed;
+}
+
+
+bool FrameElider::PropagateIntoBlock(InstructionBlock* block) {
+ // Already marked, nothing to do...
+ if (block->needs_frame()) return false;
+
+ // Never mark the dummy end node, otherwise we might incorrectly decide to
+ // put frame deconstruction code there later,
+ if (block->successors().empty()) return false;
+
+ // Propagate towards the end ("downwards") if there is a predecessor needing
+ // a frame, but don't "bleed" from deferred code to non-deferred code.
+ for (auto pred : block->predecessors()) {
+ if (InstructionBlockAt(pred)->needs_frame() &&
+ (!InstructionBlockAt(pred)->IsDeferred() || block->IsDeferred())) {
+ block->mark_needs_frame();
+ return true;
+ }
+ }
+
+ // Propagate towards start ("upwards") if there are successors and all of
+ // them need a frame.
+ for (auto succ : block->successors()) {
+ if (!InstructionBlockAt(succ)->needs_frame()) return false;
+ }
+ block->mark_needs_frame();
+ return true;
+}
+
+
+const InstructionBlocks& FrameElider::instruction_blocks() const {
+ return code_->instruction_blocks();
+}
+
+
+InstructionBlock* FrameElider::InstructionBlockAt(RpoNumber rpo_number) const {
+ return code_->InstructionBlockAt(rpo_number);
+}
+
+
+Instruction* FrameElider::InstructionAt(int index) const {
+ return code_->InstructionAt(index);
+}
+
+} // namespace compiler
+} // namespace internal
+} // namespace v8