Revert "Check for data races when reading JIT/DEX entries."

This reverts commit 85b5fecec920208ec43b42488f08d4c2e5aaeda2.

Reason for revert: Breaks ART tests, reverting to investigate.
Exempt-From-Owner-Approval: Revert.

(cherry picked from commit b9cc4fbb268652744c812415cb2e5d1fbe04879a)

Bug: 130406806
Change-Id: I634e37060b97484d627fc544e3b406fd90aaa784

1 files changed, 179 insertions, 0 deletions

diff --git a/libunwindstack/DexFiles.cpp b/libunwindstack/DexFiles.cpp
new file mode 100644
index 000000000..63a77e50f
--- /dev/null
+++ b/libunwindstack/DexFiles.cpp
@@ -0,0 +1,179 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <memory>
+
+#include <unwindstack/DexFiles.h>
+#include <unwindstack/MapInfo.h>
+#include <unwindstack/Maps.h>
+#include <unwindstack/Memory.h>
+
+#include "DexFile.h"
+
+namespace unwindstack {
+
+struct DEXFileEntry32 {
+  uint32_t next;
+  uint32_t prev;
+  uint32_t dex_file;
+};
+
+struct DEXFileEntry64 {
+  uint64_t next;
+  uint64_t prev;
+  uint64_t dex_file;
+};
+
+DexFiles::DexFiles(std::shared_ptr<Memory>& memory) : Global(memory) {}
+
+DexFiles::DexFiles(std::shared_ptr<Memory>& memory, std::vector<std::string>& search_libs)
+    : Global(memory, search_libs) {}
+
+DexFiles::~DexFiles() {}
+
+void DexFiles::ProcessArch() {
+  switch (arch()) {
+    case ARCH_ARM:
+    case ARCH_MIPS:
+    case ARCH_X86:
+      read_entry_ptr_func_ = &DexFiles::ReadEntryPtr32;
+      read_entry_func_ = &DexFiles::ReadEntry32;
+      break;
+
+    case ARCH_ARM64:
+    case ARCH_MIPS64:
+    case ARCH_X86_64:
+      read_entry_ptr_func_ = &DexFiles::ReadEntryPtr64;
+      read_entry_func_ = &DexFiles::ReadEntry64;
+      break;
+
+    case ARCH_UNKNOWN:
+      abort();
+  }
+}
+
+uint64_t DexFiles::ReadEntryPtr32(uint64_t addr) {
+  uint32_t entry;
+  const uint32_t field_offset = 12;  // offset of first_entry_ in the descriptor struct.
+  if (!memory_->ReadFully(addr + field_offset, &entry, sizeof(entry))) {
+    return 0;
+  }
+  return entry;
+}
+
+uint64_t DexFiles::ReadEntryPtr64(uint64_t addr) {
+  uint64_t entry;
+  const uint32_t field_offset = 16;  // offset of first_entry_ in the descriptor struct.
+  if (!memory_->ReadFully(addr + field_offset, &entry, sizeof(entry))) {
+    return 0;
+  }
+  return entry;
+}
+
+bool DexFiles::ReadEntry32() {
+  DEXFileEntry32 entry;
+  if (!memory_->ReadFully(entry_addr_, &entry, sizeof(entry)) || entry.dex_file == 0) {
+    entry_addr_ = 0;
+    return false;
+  }
+
+  addrs_.push_back(entry.dex_file);
+  entry_addr_ = entry.next;
+  return true;
+}
+
+bool DexFiles::ReadEntry64() {
+  DEXFileEntry64 entry;
+  if (!memory_->ReadFully(entry_addr_, &entry, sizeof(entry)) || entry.dex_file == 0) {
+    entry_addr_ = 0;
+    return false;
+  }
+
+  addrs_.push_back(entry.dex_file);
+  entry_addr_ = entry.next;
+  return true;
+}
+
+bool DexFiles::ReadVariableData(uint64_t ptr_offset) {
+  entry_addr_ = (this->*read_entry_ptr_func_)(ptr_offset);
+  return entry_addr_ != 0;
+}
+
+void DexFiles::Init(Maps* maps) {
+  if (initialized_) {
+    return;
+  }
+  initialized_ = true;
+  entry_addr_ = 0;
+
+  FindAndReadVariable(maps, "__dex_debug_descriptor");
+}
+
+DexFile* DexFiles::GetDexFile(uint64_t dex_file_offset, MapInfo* info) {
+  // Lock while processing the data.
+  DexFile* dex_file;
+  auto entry = files_.find(dex_file_offset);
+  if (entry == files_.end()) {
+    std::unique_ptr<DexFile> new_dex_file = DexFile::Create(dex_file_offset, memory_.get(), info);
+    dex_file = new_dex_file.get();
+    files_[dex_file_offset] = std::move(new_dex_file);
+  } else {
+    dex_file = entry->second.get();
+  }
+  return dex_file;
+}
+
+bool DexFiles::GetAddr(size_t index, uint64_t* addr) {
+  if (index < addrs_.size()) {
+    *addr = addrs_[index];
+    return true;
+  }
+  if (entry_addr_ != 0 && (this->*read_entry_func_)()) {
+    *addr = addrs_.back();
+    return true;
+  }
+  return false;
+}
+
+void DexFiles::GetMethodInformation(Maps* maps, MapInfo* info, uint64_t dex_pc,
+                                    std::string* method_name, uint64_t* method_offset) {
+  std::lock_guard<std::mutex> guard(lock_);
+  if (!initialized_) {
+    Init(maps);
+  }
+
+  size_t index = 0;
+  uint64_t addr;
+  while (GetAddr(index++, &addr)) {
+    if (addr < info->start || addr >= info->end) {
+      continue;
+    }
+
+    DexFile* dex_file = GetDexFile(addr, info);
+    if (dex_file != nullptr &&
+        dex_file->GetMethodInformation(dex_pc - addr, method_name, method_offset)) {
+      break;
+    }
+  }
+}
+
+}  // namespace unwindstack