1 //===-- HistoryUnwind.cpp ---------------------------------------*- 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 #include "lldb/lldb-private.h"
10 
11 #include "Plugins/Process/Utility/HistoryUnwind.h"
12 #include "Plugins/Process/Utility/RegisterContextHistory.h"
13 
14 #include "lldb/Target/Process.h"
15 #include "lldb/Target/StackFrame.h"
16 #include "lldb/Target/Target.h"
17 #include "lldb/Target/Thread.h"
18 
19 #include <memory>
20 
21 using namespace lldb;
22 using namespace lldb_private;
23 
24 // Constructor
25 
26 HistoryUnwind::HistoryUnwind(Thread &thread, std::vector<lldb::addr_t> pcs)
27     : Unwind(thread), m_pcs(pcs) {}
28 
29 // Destructor
30 
31 HistoryUnwind::~HistoryUnwind() {}
32 
33 void HistoryUnwind::DoClear() {
34   std::lock_guard<std::recursive_mutex> guard(m_unwind_mutex);
35   m_pcs.clear();
36 }
37 
38 lldb::RegisterContextSP
39 HistoryUnwind::DoCreateRegisterContextForFrame(StackFrame *frame) {
40   RegisterContextSP rctx;
41   if (frame) {
42     addr_t pc = frame->GetFrameCodeAddress().GetLoadAddress(
43         &frame->GetThread()->GetProcess()->GetTarget());
44     if (pc != LLDB_INVALID_ADDRESS) {
45       rctx = std::make_shared<RegisterContextHistory>(
46           *frame->GetThread().get(), frame->GetConcreteFrameIndex(),
47           frame->GetThread()->GetProcess()->GetAddressByteSize(), pc);
48     }
49   }
50   return rctx;
51 }
52 
53 bool HistoryUnwind::DoGetFrameInfoAtIndex(uint32_t frame_idx, lldb::addr_t &cfa,
54                                           lldb::addr_t &pc,
55                                           bool &behaves_like_zeroth_frame) {
56   // FIXME do not throw away the lock after we acquire it..
57   std::unique_lock<std::recursive_mutex> guard(m_unwind_mutex);
58   guard.unlock();
59   if (frame_idx < m_pcs.size()) {
60     cfa = frame_idx;
61     pc = m_pcs[frame_idx];
62     behaves_like_zeroth_frame = (frame_idx == 0);
63     return true;
64   }
65   return false;
66 }
67 
68 uint32_t HistoryUnwind::DoGetFrameCount() { return m_pcs.size(); }
69