kc3-lang/angle/src/common/backtrace_utils_android.cpp

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• Hash : f62405c5
  Author :
  Date : 2022-10-31T18:47:52
  

  Add utilities to get the Android backtrace
  
  * Added getBacktraceInfo(), which returns the backtrace information
    from the ANGLE code, including the addresses and the symbols if
    possible
  
    * Returns the data in an instance of the new class BacktraceInfo.
  
    * In order to access this function, backtrace_utils.h has been
      included in vk_utils.h
  
  * New GN flag to make use of this feature:
  
    * angle_enable_unwind_backtrace_support
  
      * Current only available on Android (debug mode)
  
    * If the flag is disabled, getBacktraceInfo() returns an empty
      object.
  
  * Added functions in util/ (per platform) to print the BacktraceInfo
    data.
  
    * Example of usage:
        angle::printBacktraceInfo(angle::getBacktraceInfo());
  
  * Minor edit: Moved cstdint from android_util.cpp to its header.
  
  Bug: b/258475923
  Change-Id: I6115462a1a2845d40c7cafc14ce52df09ecdcf34
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3995843
  Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
  Reviewed-by: Charlie Lao <cclao@google.com>
  Commit-Queue: Amirali Abdolrashidi <abdolrashidi@google.com>
  

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• src/common/backtrace_utils_android.cpp

• //
  // Copyright 2022 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  // backtrace_utils_android.cpp:
  //   Implements the functions related to the backtrace info class for Android platforms.
  //
  
  #include "backtrace_utils.h"
  
  #include <dlfcn.h>
  #include <unwind.h>
  
  namespace
  {
  
  // Size limit for the backtrace obtained from the device.
  constexpr uint32_t kMaxBacktraceSize = 16;
  
  struct UnwindCallbackFnState
  {
      UnwindCallbackFnState() : current(nullptr), end(nullptr) {}
      UnwindCallbackFnState(void **current, void **end) : current(current), end(end) {}
      void **current;
      void **end;
  };
  
  // Unwind callback function, which is called until the end of stack is reached.
  _Unwind_Reason_Code unwindCallbackFn(struct _Unwind_Context *context, void *args)
  {
      auto *state = reinterpret_cast<UnwindCallbackFnState *>(args);
  
      // Get the instruction pointer.
      uintptr_t ip = _Unwind_GetIP(context);
      if (ip == 0)
      {
          return _URC_NO_REASON;
      }
  
      // The buffer is populated at the current location with the instruction pointer address. The
      // current value is incremented to prepare for the next entry in the stack trace. Once "current"
      // gets to "end", the callback should stop.
      if (state->current == state->end)
      {
          return _URC_END_OF_STACK;
      }
  
      *state->current++ = reinterpret_cast<void *>(ip);
      return _URC_NO_REASON;
  }
  }  // namespace
  
  namespace angle
  {
  
  void BacktraceInfo::populateBacktraceInfo(void **stackAddressBuffer, size_t stackAddressCount)
  {
      ASSERT(mStackAddresses.empty() && mStackSymbols.empty());
  
      for (size_t i = 0; i < stackAddressCount; i++)
      {
          void *stackAddr = stackAddressBuffer[i];
          mStackAddresses.push_back(stackAddr);
  
          // Get the symbol if possible. dladdr() returns 0 on failure.
          Dl_info dlInfo;
          if (dladdr(stackAddr, &dlInfo) != 0 && dlInfo.dli_sname)
          {
              mStackSymbols.emplace_back(dlInfo.dli_sname);
          }
          else
          {
              mStackSymbols.emplace_back("unknown_symbol");
          }
      }
  
      ASSERT(mStackAddresses.size() == mStackSymbols.size());
  }
  
  BacktraceInfo getBacktraceInfo()
  {
      void *stackAddrBuffer[kMaxBacktraceSize];
  
      UnwindCallbackFnState unwindFnState(stackAddrBuffer, stackAddrBuffer + kMaxBacktraceSize);
      _Unwind_Backtrace(unwindCallbackFn, &unwindFnState);
  
      // The number of the collected IPs is shown by how far "current" has moved.
      auto stackAddressCount = static_cast<size_t>(unwindFnState.current - stackAddrBuffer);
  
      BacktraceInfo backtraceInfo;
      backtraceInfo.populateBacktraceInfo(stackAddrBuffer, stackAddressCount);
      return backtraceInfo;
  }
  
  // The following function has been defined in each platform separately.
  // - void printBacktraceInfo(BacktraceInfo backtraceInfo);
  
  }  // namespace angle
  

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