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Commit ca09ce90 authored by Christopher Ferris's avatar Christopher Ferris
Browse files

Discards frames for code within library. 

When doing a local unwind, do not include the frames that come
from either libunwind or libbacktrace.

Bug: 11518609
Change-Id: I0ec8d823aebbfa0903e61b16b7e5663f3fd65e78
parent 9dc41d5d

libbacktrace/BacktraceCurrent.cpp

+11 −0
Original line number Original line Diff line number Diff line
@@ -14,6 +14,7 @@ 
 * limitations under the License.

 * limitations under the License.

 */

 */





#define _GNU_SOURCE 1

#include <errno.h>

#include <errno.h>

#include <stdint.h>

#include <stdint.h>

#include <string.h>

#include <string.h>
@@ -73,6 +74,16 @@ bool BacktraceCurrent::Unwind(size_t num_ignore_frames, ucontext_t* ucontext) { 
  return UnwindFromContext(num_ignore_frames, nullptr);

  return UnwindFromContext(num_ignore_frames, nullptr);

}

}





bool BacktraceCurrent::DiscardFrame(const backtrace_frame_data_t& frame) {

  if (BacktraceMap::IsValid(frame.map)) {

    const std::string library = basename(frame.map.name.c_str());

    if (library == "libunwind.so" || library == "libbacktrace.so") {

      return true;

    }

  }

  return false;

}



static pthread_mutex_t g_sigaction_mutex = PTHREAD_MUTEX_INITIALIZER;

static pthread_mutex_t g_sigaction_mutex = PTHREAD_MUTEX_INITIALIZER;





static void SignalHandler(int, siginfo_t*, void* sigcontext) {

static void SignalHandler(int, siginfo_t*, void* sigcontext) {

libbacktrace/BacktraceCurrent.h

+3 −0
Original line number Original line Diff line number Diff line
@@ -46,6 +46,9 @@ public: 




  bool Unwind(size_t num_ignore_frames, ucontext_t* ucontext) override;

  bool Unwind(size_t num_ignore_frames, ucontext_t* ucontext) override;





protected:

  bool DiscardFrame(const backtrace_frame_data_t& frame);



private:

private:

  bool UnwindThread(size_t num_ignore_frames);

  bool UnwindThread(size_t num_ignore_frames);

libbacktrace/UnwindCurrent.cpp

+22 −17
Original line number Original line Diff line number Diff line
@@ -99,7 +99,6 @@ bool UnwindCurrent::UnwindFromContext(size_t num_ignore_frames, ucontext_t* ucon 
      break;

      break;

    }

    }





    if (num_ignore_frames == 0) {

    frames_.resize(num_frames+1);

    frames_.resize(num_frames+1);

    backtrace_frame_data_t* frame = &frames_.at(num_frames);

    backtrace_frame_data_t* frame = &frames_.at(num_frames);

    frame->num = num_frames;

    frame->num = num_frames;
@@ -107,18 +106,24 @@ bool UnwindCurrent::UnwindFromContext(size_t num_ignore_frames, ucontext_t* ucon 
    frame->sp = static_cast<uintptr_t>(sp);

    frame->sp = static_cast<uintptr_t>(sp);

    frame->stack_size = 0;

    frame->stack_size = 0;





    FillInMap(frame->pc, &frame->map);

    // Check to see if we should skip this frame because it's coming

    // from within the library, and we are doing a local unwind.

    if (ucontext != nullptr || num_frames != 0 || !DiscardFrame(*frame)) {

      if (num_ignore_frames == 0) {

        // GetFunctionName is an expensive call, only do it if we are

        // keeping the frame.

        frame->func_name = GetFunctionName(frame->pc, &frame->func_offset);

        if (num_frames > 0) {

        if (num_frames > 0) {

          // Set the stack size for the previous frame.

          // Set the stack size for the previous frame.

          backtrace_frame_data_t* prev = &frames_.at(num_frames-1);

          backtrace_frame_data_t* prev = &frames_.at(num_frames-1);

          prev->stack_size = frame->sp - prev->sp;

          prev->stack_size = frame->sp - prev->sp;

        }

        }



      frame->func_name = GetFunctionName(frame->pc, &frame->func_offset);

      FillInMap(frame->pc, &frame->map);

        num_frames++;

        num_frames++;

      } else {

      } else {

        num_ignore_frames--;

        num_ignore_frames--;

      }

      }

    }

    ret = unw_step (cursor.get());

    ret = unw_step (cursor.get());

  } while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);

  } while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);

libbacktrace/backtrace_test.cpp

+18 −0
Original line number Original line Diff line number Diff line
@@ -14,6 +14,7 @@ 
 * limitations under the License.

 * limitations under the License.

 */

 */





#define _GNU_SOURCE 1

#include <dirent.h>

#include <dirent.h>

#include <errno.h>

#include <errno.h>

#include <inttypes.h>

#include <inttypes.h>
@@ -200,6 +201,23 @@ bool WaitForNonZero(int32_t* value, uint64_t seconds) { 
  return false;

  return false;

}

}





TEST(libbacktrace, local_no_unwind_frames) {

  // Verify that a local unwind does not include any frames within

  // libunwind or libbacktrace.

  std::unique_ptr<Backtrace> backtrace(Backtrace::Create(getpid(), getpid()));

  ASSERT_TRUE(backtrace->Unwind(0));



  ASSERT_TRUE(backtrace->NumFrames() != 0);

  for (const auto& frame : *backtrace ) {

    if (BacktraceMap::IsValid(frame.map)) {

      const std::string name = basename(frame.map.name.c_str());

      ASSERT_TRUE(name != "libunwind.so" && name != "libbacktrace.so")

        << DumpFrames(backtrace.get());

    }

    break;

  }

}



TEST(libbacktrace, local_trace) {

TEST(libbacktrace, local_trace) {

  ASSERT_NE(test_level_one(1, 2, 3, 4, VerifyLevelBacktrace, nullptr), 0);

  ASSERT_NE(test_level_one(1, 2, 3, 4, VerifyLevelBacktrace, nullptr), 0);

}

}