4f5337a2b6
When compiling on a laptop I like to concatenate the small test files. This makes a big difference to compile times. These changes make that easier. R=ulan@chromium.org BUG= Review URL: https://codereview.chromium.org/1163803002 Cr-Commit-Position: refs/heads/master@{#28742}
56 lines
1.7 KiB
C++
56 lines
1.7 KiB
C++
// Copyright 2013 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "src/hydrogen-mark-unreachable.h"
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namespace v8 {
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namespace internal {
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void HMarkUnreachableBlocksPhase::MarkUnreachableBlocks() {
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// If there is unreachable code in the graph, propagate the unreachable marks
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// using a fixed-point iteration.
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bool changed = true;
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const ZoneList<HBasicBlock*>* blocks = graph()->blocks();
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while (changed) {
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changed = false;
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for (int i = 0; i < blocks->length(); i++) {
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HBasicBlock* block = blocks->at(i);
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if (!block->IsReachable()) continue;
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bool is_reachable = blocks->at(0) == block;
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for (HPredecessorIterator it(block); !it.Done(); it.Advance()) {
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HBasicBlock* predecessor = it.Current();
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// A block is reachable if one of its predecessors is reachable,
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// doesn't deoptimize and either is known to transfer control to the
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// block or has a control flow instruction for which the next block
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// cannot be determined.
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if (predecessor->IsReachable() && !predecessor->IsDeoptimizing()) {
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HBasicBlock* pred_succ;
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bool known_pred_succ =
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predecessor->end()->KnownSuccessorBlock(&pred_succ);
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if (!known_pred_succ || pred_succ == block) {
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is_reachable = true;
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break;
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}
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}
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if (block->is_osr_entry()) {
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is_reachable = true;
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}
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}
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if (!is_reachable) {
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block->MarkUnreachable();
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changed = true;
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}
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}
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}
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}
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void HMarkUnreachableBlocksPhase::Run() {
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MarkUnreachableBlocks();
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}
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} // namespace internal
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} // namespace v8
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