JavaScriptCore-1097.3.tar.gz

[apple/javascriptcore.git] / bytecode / GetByIdStatus.cpp

diff --git a/bytecode/GetByIdStatus.cpp b/bytecode/GetByIdStatus.cpp
new file mode 100644 (file)
index 0000000..11aead3
--- /dev/null
+++ b/bytecode/GetByIdStatus.cpp
@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2012 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 "GetByIdStatus.h"
+
+#include "CodeBlock.h"
+#include "LowLevelInterpreter.h"
+
+namespace JSC {
+
+GetByIdStatus GetByIdStatus::computeFromLLInt(CodeBlock* profiledBlock, unsigned bytecodeIndex, Identifier& ident)
+{
+    UNUSED_PARAM(profiledBlock);
+    UNUSED_PARAM(bytecodeIndex);
+    UNUSED_PARAM(ident);
+#if ENABLE(LLINT)
+    Instruction* instruction = profiledBlock->instructions().begin() + bytecodeIndex;
+    
+    if (instruction[0].u.opcode == llint_op_method_check)
+        instruction++;
+
+    Structure* structure = instruction[4].u.structure.get();
+    if (!structure)
+        return GetByIdStatus(NoInformation, StructureSet(), notFound, false);
+    
+    size_t offset = structure->get(*profiledBlock->globalData(), ident);
+    if (offset == notFound)
+        return GetByIdStatus(NoInformation, StructureSet(), notFound, false);
+    
+    return GetByIdStatus(SimpleDirect, StructureSet(structure), offset, false);
+#else
+    return GetByIdStatus(NoInformation, StructureSet(), notFound, false);
+#endif
+}
+
+GetByIdStatus GetByIdStatus::computeFor(CodeBlock* profiledBlock, unsigned bytecodeIndex, Identifier& ident)
+{
+    UNUSED_PARAM(profiledBlock);
+    UNUSED_PARAM(bytecodeIndex);
+    UNUSED_PARAM(ident);
+#if ENABLE(JIT) && ENABLE(VALUE_PROFILER)
+    if (!profiledBlock->numberOfStructureStubInfos())
+        return computeFromLLInt(profiledBlock, bytecodeIndex, ident);
+    
+    // First check if it makes either calls, in which case we want to be super careful, or
+    // if it's not set at all, in which case we punt.
+    StructureStubInfo& stubInfo = profiledBlock->getStubInfo(bytecodeIndex);
+    if (!stubInfo.seen)
+        return computeFromLLInt(profiledBlock, bytecodeIndex, ident);
+    
+    PolymorphicAccessStructureList* list;
+    int listSize;
+    switch (stubInfo.accessType) {
+    case access_get_by_id_self_list:
+        list = stubInfo.u.getByIdSelfList.structureList;
+        listSize = stubInfo.u.getByIdSelfList.listSize;
+        break;
+    case access_get_by_id_proto_list:
+        list = stubInfo.u.getByIdProtoList.structureList;
+        listSize = stubInfo.u.getByIdProtoList.listSize;
+        break;
+    default:
+        list = 0;
+        listSize = 0;
+        break;
+    }
+    for (int i = 0; i < listSize; ++i) {
+        if (!list->list[i].isDirect)
+            return GetByIdStatus(MakesCalls, StructureSet(), notFound, true);
+    }
+    
+    // Next check if it takes slow case, in which case we want to be kind of careful.
+    if (profiledBlock->likelyToTakeSlowCase(bytecodeIndex))
+        return GetByIdStatus(TakesSlowPath, StructureSet(), notFound, true);
+    
+    // Finally figure out if we can derive an access strategy.
+    GetByIdStatus result;
+    result.m_wasSeenInJIT = true;
+    switch (stubInfo.accessType) {
+    case access_unset:
+        return computeFromLLInt(profiledBlock, bytecodeIndex, ident);
+        
+    case access_get_by_id_self: {
+        Structure* structure = stubInfo.u.getByIdSelf.baseObjectStructure.get();
+        result.m_offset = structure->get(*profiledBlock->globalData(), ident);
+        
+        if (result.m_offset != notFound)
+            result.m_structureSet.add(structure);
+        
+        if (result.m_offset != notFound)
+            ASSERT(result.m_structureSet.size());
+        break;
+    }
+        
+    case access_get_by_id_self_list: {
+        PolymorphicAccessStructureList* list = stubInfo.u.getByIdProtoList.structureList;
+        unsigned size = stubInfo.u.getByIdProtoList.listSize;
+        for (unsigned i = 0; i < size; ++i) {
+            ASSERT(list->list[i].isDirect);
+            
+            Structure* structure = list->list[i].base.get();
+            if (result.m_structureSet.contains(structure))
+                continue;
+            
+            size_t myOffset = structure->get(*profiledBlock->globalData(), ident);
+            
+            if (myOffset == notFound) {
+                result.m_offset = notFound;
+                break;
+            }
+                    
+            if (!i)
+                result.m_offset = myOffset;
+            else if (result.m_offset != myOffset) {
+                result.m_offset = notFound;
+                break;
+            }
+                    
+            result.m_structureSet.add(structure);
+        }
+                    
+        if (result.m_offset != notFound)
+            ASSERT(result.m_structureSet.size());
+        break;
+    }
+        
+    default:
+        ASSERT(result.m_offset == notFound);
+        break;
+    }
+    
+    if (result.m_offset == notFound) {
+        result.m_state = TakesSlowPath;
+        result.m_structureSet.clear();
+    } else
+        result.m_state = SimpleDirect;
+    
+    return result;
+#else // ENABLE(JIT)
+    return GetByIdStatus(NoInformation, StructureSet(), notFound, false);
+#endif // ENABLE(JIT)
+}
+
+} // namespace JSC
+