1 files changed, 0 insertions, 182 deletions
diff --git a/source/Plugins/Process/Linux/SingleStepCheck.cpp b/source/Plugins/Process/Linux/SingleStepCheck.cpp
deleted file mode 100644
index c57a2daf2275..000000000000
--- a/source/Plugins/Process/Linux/SingleStepCheck.cpp
+++ /dev/null
@@ -1,182 +0,0 @@
-//===-- SingleStepCheck.cpp ----------------------------------- -*- C++ -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#include "SingleStepCheck.h"
-
-#include <sched.h>
-#include <signal.h>
-#include <sys/wait.h>
-#include <unistd.h>
-
-#include "NativeProcessLinux.h"
-
-#include "llvm/Support/Compiler.h"
-
-#include "Plugins/Process/POSIX/ProcessPOSIXLog.h"
-#include "lldb/Host/linux/Ptrace.h"
-#include "lldb/Utility/Status.h"
-
-using namespace lldb;
-using namespace lldb_private;
-using namespace lldb_private::process_linux;
-
-#if defined(__arm64__) || defined(__aarch64__)
-namespace {
-
-void LLVM_ATTRIBUTE_NORETURN Child() {
-  if (ptrace(PTRACE_TRACEME, 0, nullptr, nullptr) == -1)
-    _exit(1);
-
-  // We just do an endless loop SIGSTOPPING ourselves until killed. The tracer
-  // will fiddle with our cpu affinities and monitor the behaviour.
-  for (;;) {
-    raise(SIGSTOP);
-
-    // Generate a bunch of instructions here, so that a single-step does not
-    // land in the raise() accidentally. If single-stepping works, we will be
-    // spinning in this loop. If it doesn't, we'll land in the raise() call
-    // above.
-    for (volatile unsigned i = 0; i < CPU_SETSIZE; ++i)
-      ;
-  }
-}
-
-struct ChildDeleter {
-  ::pid_t pid;
-
-  ~ChildDeleter() {
-    int status;
-    kill(pid, SIGKILL);            // Kill the child.
-    waitpid(pid, &status, __WALL); // Pick up the remains.
-  }
-};
-
-bool WorkaroundNeeded() {
-  // We shall spawn a child, and use it to verify the debug capabilities of the
-  // cpu. We shall iterate through the cpus, bind the child to each one in
-  // turn, and verify that single-stepping works on that cpu. A workaround is
-  // needed if we find at least one broken cpu.
-
-  Log *log = ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD);
-  ::pid_t child_pid = fork();
-  if (child_pid == -1) {
-    LLDB_LOG(log, "failed to fork(): {0}", Status(errno, eErrorTypePOSIX));
-    return false;
-  }
-  if (child_pid == 0)
-    Child();
-
-  ChildDeleter child_deleter{child_pid};
-  cpu_set_t available_cpus;
-  if (sched_getaffinity(child_pid, sizeof available_cpus, &available_cpus) ==
-      -1) {
-    LLDB_LOG(log, "failed to get available cpus: {0}",
-             Status(errno, eErrorTypePOSIX));
-    return false;
-  }
-
-  int status;
-  ::pid_t wpid = waitpid(child_pid, &status, __WALL);
-  if (wpid != child_pid || !WIFSTOPPED(status)) {
-    LLDB_LOG(log, "waitpid() failed (status = {0:x}): {1}", status,
-             Status(errno, eErrorTypePOSIX));
-    return false;
-  }
-
-  unsigned cpu;
-  for (cpu = 0; cpu < CPU_SETSIZE; ++cpu) {
-    if (!CPU_ISSET(cpu, &available_cpus))
-      continue;
-
-    cpu_set_t cpus;
-    CPU_ZERO(&cpus);
-    CPU_SET(cpu, &cpus);
-    if (sched_setaffinity(child_pid, sizeof cpus, &cpus) == -1) {
-      LLDB_LOG(log, "failed to switch to cpu {0}: {1}", cpu,
-               Status(errno, eErrorTypePOSIX));
-      continue;
-    }
-
-    int status;
-    Status error =
-        NativeProcessLinux::PtraceWrapper(PTRACE_SINGLESTEP, child_pid);
-    if (error.Fail()) {
-      LLDB_LOG(log, "single step failed: {0}", error);
-      break;
-    }
-
-    wpid = waitpid(child_pid, &status, __WALL);
-    if (wpid != child_pid || !WIFSTOPPED(status)) {
-      LLDB_LOG(log, "waitpid() failed (status = {0:x}): {1}", status,
-               Status(errno, eErrorTypePOSIX));
-      break;
-    }
-    if (WSTOPSIG(status) != SIGTRAP) {
-      LLDB_LOG(log, "single stepping on cpu {0} failed with status {1:x}", cpu,
-               status);
-      break;
-    }
-  }
-
-  // cpu is either the index of the first broken cpu, or CPU_SETSIZE.
-  if (cpu == 0) {
-    LLDB_LOG(log,
-             "SINGLE STEPPING ON FIRST CPU IS NOT WORKING. DEBUGGING "
-             "LIKELY TO BE UNRELIABLE.");
-    // No point in trying to fiddle with the affinities, just give it our best
-    // shot and see how it goes.
-    return false;
-  }
-
-  return cpu != CPU_SETSIZE;
-}
-
-} // end anonymous namespace
-
-std::unique_ptr<SingleStepWorkaround> SingleStepWorkaround::Get(::pid_t tid) {
-  Log *log = ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD);
-
-  static bool workaround_needed = WorkaroundNeeded();
-  if (!workaround_needed) {
-    LLDB_LOG(log, "workaround for thread {0} not needed", tid);
-    return nullptr;
-  }
-
-  cpu_set_t original_set;
-  if (sched_getaffinity(tid, sizeof original_set, &original_set) != 0) {
-    // This should really not fail. But, just in case...
-    LLDB_LOG(log, "Unable to get cpu affinity for thread {0}: {1}", tid,
-             Status(errno, eErrorTypePOSIX));
-    return nullptr;
-  }
-
-  cpu_set_t set;
-  CPU_ZERO(&set);
-  CPU_SET(0, &set);
-  if (sched_setaffinity(tid, sizeof set, &set) != 0) {
-    // This may fail in very locked down systems, if the thread is not allowed
-    // to run on cpu 0. If that happens, only thing we can do is it log it and
-    // continue...
-    LLDB_LOG(log, "Unable to set cpu affinity for thread {0}: {1}", tid,
-             Status(errno, eErrorTypePOSIX));
-  }
-
-  LLDB_LOG(log, "workaround for thread {0} prepared", tid);
-  return llvm::make_unique<SingleStepWorkaround>(tid, original_set);
-}
-
-SingleStepWorkaround::~SingleStepWorkaround() {
-  Log *log = ProcessPOSIXLog::GetLogIfAllCategoriesSet(POSIX_LOG_THREAD);
-  LLDB_LOG(log, "Removing workaround");
-  if (sched_setaffinity(m_tid, sizeof m_original_set, &m_original_set) != 0) {
-    LLDB_LOG(log, "Unable to reset cpu affinity for thread {0}: {1}", m_tid,
-             Status(errno, eErrorTypePOSIX));
-  }
-}
-#endif