src/ffi/backtrace_utils.h

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */
/*!
 * \file backtrace.h
 * \brief Common headers for backtrace.
 * \note We use the term "backtrace" to be consistent with python naming convention.
 */
#ifndef TVM_FFI_TRACEBACK_H_
#define TVM_FFI_TRACEBACK_H_

#include <tvm/ffi/base_details.h>

#include <cstring>
#include <sstream>
#include <string>
#include <vector>

namespace tvm {
namespace ffi {

#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable : 4996)  // std::getenv is unsafe
#endif

inline int32_t GetBacktraceLimit() {
  if (const char* env = std::getenv("TVM_TRACEBACK_LIMIT")) {
    return std::stoi(env);
  }
  return 512;
}

#ifdef _MSC_VER
#pragma warning(pop)
#endif

/*!
 * \brief List frame patterns that should be excluded as they contain less information
 */
inline bool ShouldExcludeFrame(const char* filename, const char* symbol) {
  if (symbol != nullptr) {
    if (strncmp(symbol, "tvm::ffi::Function", 18) == 0) {
      return true;
    }
    if (strncmp(symbol, "tvm::ffi::details::", 19) == 0) {
      return true;
    }
    if (strncmp(symbol, "TVMFFIBacktrace", 15) == 0) {
      return true;
    }
    if (strncmp(symbol, "TVMFFIErrorSetRaisedFromCStr", 28) == 0) {
      return true;
    }
    if (strncmp(symbol, "TVMFFIErrorSetRaisedFromCStrParts", 33) == 0) {
      return true;
    }
    // C++ stdlib frames
    if (strncmp(symbol, "__libc_", 7) == 0) {
      return true;
    }
    // libffi.so stack frames.  These may also show up as numeric
    // addresses with no symbol name.  This could be improved in the
    // future by using dladdr() to check whether an address is contained
    // in libffi.so
    if (strncmp(symbol, "ffi_call_", 9) == 0) {
      return true;
    }
  }
  if (filename) {
    // Stack frames for TVM FFI
    if (strstr(filename, "include/tvm/ffi/error.h") != nullptr) {
      return true;
    }
    if (strstr(filename, "include/tvm/ffi/function_details.h") != nullptr) {
      return true;
    }
    if (strstr(filename, "include/tvm/ffi/function.h") != nullptr) {
      return true;
    }
    if (strstr(filename, "include/tvm/ffi/any.h") != nullptr) {
      return true;
    }
    // C++ stdlib frames
    if (strstr(filename, "include/c++/") != nullptr) {
      return true;
    }
  }
  return false;
}

/**
 * \brief List frames that should stop the backtrace.
 * \param filename The filename of the frame.
 * \param symbol The symbol name of the frame.
 * \return true if the frame should stop the backtrace.
 * \note We stop backtrace at the FFI boundary.
 */
inline bool DetectFFIBoundary(const char* filename, const char* symbol) {
  if (symbol != nullptr) {
    if (strncmp(symbol, "TVMFFIFunctionCall", 18) == 0) {
      return true;
    }
    // python ABI functions
    if (strncmp(symbol, "slot_tp_call", 12) == 0) {
      return true;
    }
    if (strncmp(symbol, "object_is_not_callable", 11) == 0) {
      return true;
    }
    // Python interpreter stack frames
    // we stop backtrace at the Python interpreter stack frames
    // since these frame will be handled from by the python side.
    if (strncmp(symbol, "_Py", 3) == 0 || strncmp(symbol, "PyObject", 8) == 0) {
      return true;
    }
  }
  return false;
}

/*!
 * \brief storage to store backtrace
 */
struct BacktraceStorage {
  /*! \brief The stream to store the backtrace. */
  std::ostringstream backtrace_stream_;
  /*! \brief The number of lines in the backtrace. */
  size_t line_count_ = 0;
  /*! \brief Maximum size of the backtrace. */
  size_t max_frame_size = GetBacktraceLimit();
  /*! \brief Number of frames to skip. */
  size_t skip_frame_count = 0;
  /*! \brief Whether to stop at the ffi boundary. */
  bool stop_at_boundary = true;

  void Append(const char* filename, const char* func, int lineno) {
    // skip frames with empty filename
    if (filename == nullptr) {
      if (func != nullptr) {
        if (strncmp(func, "0x0", 3) == 0) {
          return;
        }
        if (strncmp(func, "<unknown>", 9) == 0) {
          return;
        }
        filename = "<unknown>";
      } else {
        return;
      }
    }
    backtrace_stream_ << "  File \"" << filename << "\"";
    backtrace_stream_ << ", line " << lineno;
    backtrace_stream_ << ", in " << func << '\n';
    line_count_++;
  }

  bool ExceedBacktraceLimit() const { return line_count_ >= max_frame_size; }

  // get backtrace in the order of most recent call last
  std::string GetBacktrace() const { return backtrace_stream_.str(); }
};

}  // namespace ffi
}  // namespace tvm

#endif  // TVM_FFI_TRACEBACK_H_