Update V8 to version 4.1.0.21
This is a cherry-pick of all commits up to and including the
4.1.0.21 cherry-pick in Chromium.
Original commit message:
Version 4.1.0.21 (cherry-pick)
Merged 206e9136bde0f2b5ae8cb77afbb1e7833e5bd412
Unlink pages from the space page list after evacuation.
BUG=430201
LOG=N
R=jkummerow@chromium.org
Review URL: https://codereview.chromium.org/953813002
Cr-Commit-Position: refs/branch-heads/4.1@{#22}
Cr-Branched-From: 2e08d2a7aa9d65d269d8c57aba82eb38a8cb0a18-refs/heads/candidates@{#25353}
---
FPIIM-449
Change-Id: I8c23c7bbb70772b4858fe8a47b64fa97ee0d1f8c
diff --git a/src/compiler/jump-threading.h b/src/compiler/jump-threading.h
new file mode 100644
index 0000000..b801fec
--- /dev/null
+++ b/src/compiler/jump-threading.h
@@ -0,0 +1,34 @@
+// 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.
+
+#ifndef V8_COMPILER_JUMP_THREADING_H_
+#define V8_COMPILER_JUMP_THREADING_H_
+
+#include "src/compiler/instruction.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+// Forwards jumps to empty basic blocks that end with a second jump to the
+// destination of the second jump, transitively.
+class JumpThreading {
+ public:
+ // Compute the forwarding map of basic blocks to their ultimate destination.
+ // Returns {true} if there is at least one block that is forwarded.
+ static bool ComputeForwarding(Zone* local_zone,
+ ZoneVector<BasicBlock::RpoNumber>& result,
+ InstructionSequence* code);
+
+ // Rewrite the instructions to forward jumps and branches.
+ // May also negate some branches.
+ static void ApplyForwarding(ZoneVector<BasicBlock::RpoNumber>& forwarding,
+ InstructionSequence* code);
+};
+
+} // namespace compiler
+} // namespace internal
+} // namespace v8
+
+#endif // V8_COMPILER_JUMP_THREADING_H