Turn propagate deoptimizing mark into a proper HPhase.

Also turn the recursion on the domination chain into a loop with
an explicit stack, to avoid possible stack overflow here.

R=dslomov@chromium.org

Review URL: https://codereview.chromium.org/19150002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15660 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen-deoptimizing-mark.cc

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "hydrogen-deoptimizing-mark.h"
+
+namespace v8 {
+namespace internal {
+
+void HPropagateDeoptimizingMarkPhase::MarkAsDeoptimizing() {
+  HBasicBlock* block = graph()->entry_block();
+  ZoneList<HBasicBlock*> stack(graph()->blocks()->length(), zone());
+  while (block != NULL) {
+    const ZoneList<HBasicBlock*>* dominated_blocks(block->dominated_blocks());
+    if (!dominated_blocks->is_empty()) {
+      if (block->IsDeoptimizing()) {
+        for (int i = 0; i < dominated_blocks->length(); ++i) {
+          dominated_blocks->at(i)->MarkAsDeoptimizing();
+        }
+      }
+      for (int i = 1; i < dominated_blocks->length(); ++i) {
+        stack.Add(dominated_blocks->at(i), zone());
+      }
+      block = dominated_blocks->at(0);
+    } else if (!stack.is_empty()) {
+      // Pop next block from stack.
+      block = stack.RemoveLast();
+    } else {
+      // All blocks processed.
+      block = NULL;
+    }
+  }
+}
+
+
+void HPropagateDeoptimizingMarkPhase::NullifyUnreachableInstructions() {
+  if (!FLAG_unreachable_code_elimination) return;
+  for (int i = 0; i < graph()->blocks()->length(); ++i) {
+    HBasicBlock* block = graph()->blocks()->at(i);
+    bool nullify = false;
+    const ZoneList<HBasicBlock*>* predecessors = block->predecessors();
+    int predecessors_length = predecessors->length();
+    bool all_predecessors_deoptimizing = (predecessors_length > 0);
+    for (int j = 0; j < predecessors_length; ++j) {
+      if (!predecessors->at(j)->IsDeoptimizing()) {
+        all_predecessors_deoptimizing = false;
+        break;
+      }
+    }
+    if (all_predecessors_deoptimizing) nullify = true;
+    for (HInstructionIterator it(block); !it.Done(); it.Advance()) {
+      HInstruction* instr = it.Current();
+      // Leave the basic structure of the graph intact.
+      if (instr->IsBlockEntry()) continue;
+      if (instr->IsControlInstruction()) continue;
+      if (instr->IsSimulate()) continue;
+      if (instr->IsEnterInlined()) continue;
+      if (instr->IsLeaveInlined()) continue;
+      if (nullify) {
+        HInstruction* last_dummy = NULL;
+        for (int j = 0; j < instr->OperandCount(); ++j) {
+          HValue* operand = instr->OperandAt(j);
+          // Insert an HDummyUse for each operand, unless the operand
+          // is an HDummyUse itself. If it's even from the same block,
+          // remember it as a potential replacement for the instruction.
+          if (operand->IsDummyUse()) {
+            if (operand->block() == instr->block() &&
+                last_dummy == NULL) {
+              last_dummy = HInstruction::cast(operand);
+            }
+            continue;
+          }
+          if (operand->IsControlInstruction()) {
+            // Inserting a dummy use for a value that's not defined anywhere
+            // will fail. Some instructions define fake inputs on such
+            // values as control flow dependencies.
+            continue;
+          }
+          HDummyUse* dummy = new(graph()->zone()) HDummyUse(operand);
+          dummy->InsertBefore(instr);
+          last_dummy = dummy;
+        }
+        if (last_dummy == NULL) last_dummy = graph()->GetConstant1();
+        instr->DeleteAndReplaceWith(last_dummy);
+        continue;
+      }
+      if (instr->IsSoftDeoptimize()) {
+        ASSERT(block->IsDeoptimizing());
+        nullify = true;
+      }
+    }
+  }
+}
+
+
+void HPropagateDeoptimizingMarkPhase::Run() {
+  // Skip this phase if there is nothing to be done anyway.
+  if (!graph()->has_soft_deoptimize()) return;
+  MarkAsDeoptimizing();
+  NullifyUnreachableInstructions();
+}
+
+} }  // namespace v8::internal

src/hydrogen-deoptimizing-mark.h

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_HYDROGEN_DEOPTIMIZING_MARK_H_
+#define V8_HYDROGEN_DEOPTIMIZING_MARK_H_
+
+#include "hydrogen.h"
+
+namespace v8 {
+namespace internal {
+
+
+// Mark all blocks that are dominated by an unconditional soft deoptimize to
+// prevent code motion across those blocks.
+class HPropagateDeoptimizingMarkPhase : public HPhase {
+ public:
+  explicit HPropagateDeoptimizingMarkPhase(HGraph* graph)
+      : HPhase("H_Propagate deoptimizing mark", graph) { }
+
+  void Run();
+
+ private:
+  void MarkAsDeoptimizing();
+  void NullifyUnreachableInstructions();
+
+  DISALLOW_COPY_AND_ASSIGN(HPropagateDeoptimizingMarkPhase);
+};
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_HYDROGEN_DEOPTIMIZING_MARK_H_

src/hydrogen.cc

@@ -37,6 +37,7 @@
 #include "hydrogen-canonicalize.h"
 #include "hydrogen-dce.h"
 #include "hydrogen-dehoist.h"
+#include "hydrogen-deoptimizing-mark.h"
 #include "hydrogen-environment-liveness.h"
 #include "hydrogen-escape-analysis.h"
 #include "hydrogen-infer-representation.h"
@@ -2427,87 +2428,6 @@ void HGraph::AssignDominators() {
 }
 
 
-// Mark all blocks that are dominated by an unconditional soft deoptimize to
-// prevent code motion across those blocks.
-void HGraph::PropagateDeoptimizingMark() {
-  HPhase phase("H_Propagate deoptimizing mark", this);
-  // Skip this phase if there is nothing to be done anyway.
-  if (!has_soft_deoptimize()) return;
-  MarkAsDeoptimizingRecursively(entry_block());
-  NullifyUnreachableInstructions();
-}
-
-
-void HGraph::MarkAsDeoptimizingRecursively(HBasicBlock* block) {
-  for (int i = 0; i < block->dominated_blocks()->length(); ++i) {
-    HBasicBlock* dominated = block->dominated_blocks()->at(i);
-    if (block->IsDeoptimizing()) dominated->MarkAsDeoptimizing();
-    MarkAsDeoptimizingRecursively(dominated);
-  }
-}
-
-
-void HGraph::NullifyUnreachableInstructions() {
-  if (!FLAG_unreachable_code_elimination) return;
-  int block_count = blocks_.length();
-  for (int i = 0; i < block_count; ++i) {
-    HBasicBlock* block = blocks_.at(i);
-    bool nullify = false;
-    const ZoneList<HBasicBlock*>* predecessors = block->predecessors();
-    int predecessors_length = predecessors->length();
-    bool all_predecessors_deoptimizing = (predecessors_length > 0);
-    for (int j = 0; j < predecessors_length; ++j) {
-      if (!predecessors->at(j)->IsDeoptimizing()) {
-        all_predecessors_deoptimizing = false;
-        break;
-      }
-    }
-    if (all_predecessors_deoptimizing) nullify = true;
-    for (HInstructionIterator it(block); !it.Done(); it.Advance()) {
-      HInstruction* instr = it.Current();
-      // Leave the basic structure of the graph intact.
-      if (instr->IsBlockEntry()) continue;
-      if (instr->IsControlInstruction()) continue;
-      if (instr->IsSimulate()) continue;
-      if (instr->IsEnterInlined()) continue;
-      if (instr->IsLeaveInlined()) continue;
-      if (nullify) {
-        HInstruction* last_dummy = NULL;
-        for (int j = 0; j < instr->OperandCount(); ++j) {
-          HValue* operand = instr->OperandAt(j);
-          // Insert an HDummyUse for each operand, unless the operand
-          // is an HDummyUse itself. If it's even from the same block,
-          // remember it as a potential replacement for the instruction.
-          if (operand->IsDummyUse()) {
-            if (operand->block() == instr->block() &&
-                last_dummy == NULL) {
-              last_dummy = HInstruction::cast(operand);
-            }
-            continue;
-          }
-          if (operand->IsControlInstruction()) {
-            // Inserting a dummy use for a value that's not defined anywhere
-            // will fail. Some instructions define fake inputs on such
-            // values as control flow dependencies.
-            continue;
-          }
-          HDummyUse* dummy = new(zone()) HDummyUse(operand);
-          dummy->InsertBefore(instr);
-          last_dummy = dummy;
-        }
-        if (last_dummy == NULL) last_dummy = GetConstant1();
-        instr->DeleteAndReplaceWith(last_dummy);
-        continue;
-      }
-      if (instr->IsSoftDeoptimize()) {
-        ASSERT(block->IsDeoptimizing());
-        nullify = true;
-      }
-    }
-  }
-}
-
-
 bool HGraph::CheckArgumentsPhiUses() {
   int block_count = blocks_.length();
   for (int i = 0; i < block_count; ++i) {
@@ -3026,7 +2946,7 @@ bool HGraph::Optimize(SmartArrayPointer<char>* bailout_reason) {
     Run<HEnvironmentLivenessAnalysisPhase>();
   }
 
-  PropagateDeoptimizingMark();
+  Run<HPropagateDeoptimizingMarkPhase>();
   if (!CheckConstPhiUses()) {
     *bailout_reason = SmartArrayPointer<char>(StrDup(
         "Unsupported phi use of const variable"));

src/hydrogen.h

@@ -304,7 +304,6 @@ class HGraph: public ZoneObject {
   void AssignDominators();
   void SetupInformativeDefinitions();
   void RestoreActualValues();
-  void PropagateDeoptimizingMark();
 
   // Returns false if there are phi-uses of the arguments-object
   // which are not supported by the optimizing compiler.
@@ -447,8 +446,6 @@ class HGraph: public ZoneObject {
     phase.Run();
   }
 
-  void MarkAsDeoptimizingRecursively(HBasicBlock* block);
-  void NullifyUnreachableInstructions();
   void RecursivelyMarkPhiDeoptimizeOnUndefined(HPhi* phi);
   void CheckForBackEdge(HBasicBlock* block, HBasicBlock* successor);
   void SetupInformativeDefinitionsInBlock(HBasicBlock* block);

tools/gyp/v8.gyp

@@ -343,6 +343,8 @@
         '../../src/hydrogen-dce.h',
         '../../src/hydrogen-dehoist.cc',
         '../../src/hydrogen-dehoist.h',
+        '../../src/hydrogen-deoptimizing-mark.cc',
+        '../../src/hydrogen-deoptimizing-mark.h',
         '../../src/hydrogen-environment-liveness.cc',
         '../../src/hydrogen-environment-liveness.h',
         '../../src/hydrogen-escape-analysis.cc',