LLDB mainline
SingleStepCheck.h
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1//===-- SingleStepCheck.h ------------------------------------- -*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef liblldb_SingleStepCheck_H_
10#define liblldb_SingleStepCheck_H_
11
12#include <memory>
13#include <sched.h>
14#include <sys/types.h>
15
16namespace lldb_private {
17namespace process_linux {
18
19// arm64 linux had a bug which prevented single-stepping and watchpoints from
20// working on non-boot cpus, due to them being incorrectly initialized after
21// coming out of suspend. This issue is particularly affecting android M, which
22// uses suspend ("doze mode") quite aggressively. This code detects that
23// situation and makes single-stepping work by doing all the step operations on
24// the boot cpu.
25//
26// The underlying issue has been fixed in android N and linux 4.4. This code can
27// be removed once these systems become obsolete.
28
29#if defined(__arm64__) || defined(__aarch64__)
30class SingleStepWorkaround {
31 ::pid_t m_tid;
32 cpu_set_t m_original_set;
33
34 SingleStepWorkaround(const SingleStepWorkaround &) = delete;
35 void operator=(const SingleStepWorkaround &) = delete;
36
37public:
38 SingleStepWorkaround(::pid_t tid, cpu_set_t original_set)
39 : m_tid(tid), m_original_set(original_set) {}
40 ~SingleStepWorkaround();
41
42 static std::unique_ptr<SingleStepWorkaround> Get(::pid_t tid);
43};
44#else
46public:
47 static std::unique_ptr<SingleStepWorkaround> Get(::pid_t tid) {
48 return nullptr;
49 }
50};
51#endif
52
53} // end namespace process_linux
54} // end namespace lldb_private
55
56#endif // #ifndef liblldb_SingleStepCheck_H_
static std::unique_ptr< SingleStepWorkaround > Get(::pid_t tid)
A class that represents a running process on the host machine.