1  /*
 2   * Copyright (C) 2019 Apple Inc. All rights reserved.
 3   *
 4   * Redistribution and use in source and binary forms, with or without
 5   * modification, are permitted provided that the following conditions
 6   * are met:
 7   * 1. Redistributions of source code must retain the above copyright
 8   *    notice, this list of conditions and the following disclaimer.
 9   * 2. Redistributions in binary form must reproduce the above copyright
10   *    notice, this list of conditions and the following disclaimer in the
11   *    documentation and/or other materials provided with the distribution.
12   *
13   * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24   */
25  
26  #include "config.h"
27  #include "CachedBytecode.h"
28  
29  #include "CachedTypes.h"
30  #include "UnlinkedFunctionExecutable.h"
31  
32  namespace JSC {
33  
34  void CachedBytecode::addGlobalUpdate(Ref<CachedBytecode> bytecode)
35  {
36      ASSERT(m_updates.isEmpty());
37      m_leafExecutables.clear();
38      copyLeafExecutables(bytecode.get());
39      m_updates.append(CacheUpdate::GlobalUpdate { WTFMove(bytecode->m_payload) });
40  }
41  
42  void CachedBytecode::addFunctionUpdate(const UnlinkedFunctionExecutable* executable, CodeSpecializationKind kind, Ref<CachedBytecode> bytecode)
43  {
44      auto it = m_leafExecutables.find(executable);
45      ASSERT(it != m_leafExecutables.end());
46      ptrdiff_t offset = it->value.base();
47      ASSERT(offset);
48      copyLeafExecutables(bytecode.get());
49      m_updates.append(CacheUpdate::FunctionUpdate { offset, kind, { executable->features(), executable->hasCapturedVariables() }, WTFMove(bytecode->m_payload) });
50  }
51  
52  void CachedBytecode::copyLeafExecutables(const CachedBytecode& bytecode)
53  {
54      for (const auto& it : bytecode.m_leafExecutables) {
55          auto addResult = m_leafExecutables.add(it.key, it.value + m_size);
56          ASSERT_UNUSED(addResult, addResult.isNewEntry);
57      }
58      m_size += bytecode.size();
59  }
60  
61  void CachedBytecode::commitUpdates(const ForEachUpdateCallback& callback) const
62  {
63      off_t offset = m_payload.size();
64      for (const auto& update : m_updates) {
65          const CachePayload* payload = nullptr;
66          if (update.isGlobal())
67              payload = &update.asGlobal().m_payload;
68          else {
69              const CacheUpdate::FunctionUpdate& functionUpdate = update.asFunction();
70              payload = &functionUpdate.m_payload;
71              {
72                  ptrdiff_t kindOffset = functionUpdate.m_kind == CodeForCall ? CachedFunctionExecutableOffsets::codeBlockForCallOffset() : CachedFunctionExecutableOffsets::codeBlockForConstructOffset();
73                  ptrdiff_t codeBlockOffset = functionUpdate.m_base + kindOffset + CachedWriteBarrierOffsets::ptrOffset() + CachedPtrOffsets::offsetOffset();
74                  ptrdiff_t offsetPayload = static_cast<ptrdiff_t>(offset) - codeBlockOffset;
75                  static_assert(std::is_same<decltype(VariableLengthObjectBase::m_offset), ptrdiff_t>::value, "");
76                  callback(codeBlockOffset, &offsetPayload, sizeof(ptrdiff_t));
77              }
78  
79              {
80                  ptrdiff_t metadataOffset = functionUpdate.m_base + CachedFunctionExecutableOffsets::metadataOffset();
81                  callback(metadataOffset, &functionUpdate.m_metadata, sizeof(functionUpdate.m_metadata));
82              }
83          }
84  
85          ASSERT(payload);
86          callback(offset, payload->data(), payload->size());
87          offset += payload->size();
88      }
89      ASSERT(static_cast<size_t>(offset) == m_size);
90  }
91  
92  } // namespace JSC