JavaScriptCore-7600.1.4.9.tar.gz

[apple/javascriptcore.git] / dfg / DFGOSRAvailabilityAnalysisPhase.cpp

diff --git a/dfg/DFGOSRAvailabilityAnalysisPhase.cpp b/dfg/DFGOSRAvailabilityAnalysisPhase.cpp
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+/*
+ * Copyright (C) 2013 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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 "config.h"
+#include "DFGOSRAvailabilityAnalysisPhase.h"
+
+#if ENABLE(DFG_JIT)
+
+#include "DFGBasicBlockInlines.h"
+#include "DFGGraph.h"
+#include "DFGInsertionSet.h"
+#include "DFGPhase.h"
+#include "JSCInlines.h"
+
+namespace JSC { namespace DFG {
+
+class OSRAvailabilityAnalysisPhase : public Phase {
+public:
+    OSRAvailabilityAnalysisPhase(Graph& graph)
+        : Phase(graph, "OSR availability analysis")
+    {
+    }
+    
+    bool run()
+    {
+        ASSERT(m_graph.m_form == SSA);
+        
+        for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
+            BasicBlock* block = m_graph.block(blockIndex);
+            if (!block)
+                continue;
+            block->ssa->availabilityAtHead.fill(Availability());
+            block->ssa->availabilityAtTail.fill(Availability());
+        }
+        
+        BasicBlock* root = m_graph.block(0);
+        for (unsigned argument = root->ssa->availabilityAtHead.numberOfArguments(); argument--;) {
+            root->ssa->availabilityAtHead.argument(argument) =
+                Availability::unavailable().withFlush(
+                    FlushedAt(FlushedJSValue, virtualRegisterForArgument(argument)));
+        }
+
+        if (m_graph.m_plan.mode == FTLForOSREntryMode) {
+            for (unsigned local = m_graph.m_profiledBlock->m_numCalleeRegisters; local--;)
+                root->ssa->availabilityAtHead.local(local) = Availability::unavailable();
+        } else {
+            for (unsigned local = root->ssa->availabilityAtHead.numberOfLocals(); local--;)
+                root->ssa->availabilityAtHead.local(local) = Availability::unavailable();
+        }
+        
+        // This could be made more efficient by processing blocks in reverse postorder.
+        Operands<Availability> availability;
+        bool changed;
+        do {
+            changed = false;
+            
+            for (BlockIndex blockIndex = 0; blockIndex < m_graph.numBlocks(); ++blockIndex) {
+                BasicBlock* block = m_graph.block(blockIndex);
+                if (!block)
+                    continue;
+                
+                availability = block->ssa->availabilityAtHead;
+                
+                for (unsigned nodeIndex = 0; nodeIndex < block->size(); ++nodeIndex) {
+                    Node* node = block->at(nodeIndex);
+                    
+                    switch (node->op()) {
+                    case SetLocal: {
+                        VariableAccessData* variable = node->variableAccessData();
+                        availability.operand(variable->local()) =
+                            Availability(node->child1().node(), variable->flushedAt());
+                        break;
+                    }
+                        
+                    case GetArgument: {
+                        VariableAccessData* variable = node->variableAccessData();
+                        availability.operand(variable->local()) =
+                            Availability(node, variable->flushedAt());
+                        break;
+                    }
+                        
+                    case MovHint: {
+                        availability.operand(node->unlinkedLocal()) =
+                            Availability(node->child1().node());
+                        break;
+                    }
+                        
+                    case ZombieHint: {
+                        availability.operand(node->unlinkedLocal()) =
+                            Availability::unavailable();
+                        break;
+                    }
+                        
+                    default:
+                        break;
+                    }
+                }
+                
+                if (availability == block->ssa->availabilityAtTail)
+                    continue;
+                
+                block->ssa->availabilityAtTail = availability;
+                changed = true;
+                
+                for (unsigned successorIndex = block->numSuccessors(); successorIndex--;) {
+                    BasicBlock* successor = block->successor(successorIndex);
+                    for (unsigned i = availability.size(); i--;) {
+                        successor->ssa->availabilityAtHead[i] = availability[i].merge(
+                            successor->ssa->availabilityAtHead[i]);
+                    }
+                }
+            }
+        } while (changed);
+        
+        return true;
+    }
+};
+
+bool performOSRAvailabilityAnalysis(Graph& graph)
+{
+    SamplingRegion samplingRegion("DFG OSR Availability Analysis Phase");
+    return runPhase<OSRAvailabilityAnalysisPhase>(graph);
+}
+
+} } // namespace JSC::DFG
+
+#endif // ENABLE(DFG_JIT)
+