1 //===-- HistoryUnwind.cpp -------------------------------------------------===//
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                              bool pcs_are_call_addresses)
28     : Unwind(thread), m_pcs(pcs),
29       m_pcs_are_call_addresses(pcs_are_call_addresses) {}
30 
31 // Destructor
32 
33 HistoryUnwind::~HistoryUnwind() = default;
34 
35 void HistoryUnwind::DoClear() {
36   std::lock_guard<std::recursive_mutex> guard(m_unwind_mutex);
37   m_pcs.clear();
38 }
39 
40 lldb::RegisterContextSP
41 HistoryUnwind::DoCreateRegisterContextForFrame(StackFrame *frame) {
42   RegisterContextSP rctx;
43   if (frame) {
44     addr_t pc = frame->GetFrameCodeAddress().GetLoadAddress(
45         &frame->GetThread()->GetProcess()->GetTarget());
46     if (pc != LLDB_INVALID_ADDRESS) {
47       rctx = std::make_shared<RegisterContextHistory>(
48           *frame->GetThread().get(), frame->GetConcreteFrameIndex(),
49           frame->GetThread()->GetProcess()->GetAddressByteSize(), pc);
50     }
51   }
52   return rctx;
53 }
54 
55 bool HistoryUnwind::DoGetFrameInfoAtIndex(uint32_t frame_idx, lldb::addr_t &cfa,
56                                           lldb::addr_t &pc,
57                                           bool &behaves_like_zeroth_frame) {
58   // FIXME do not throw away the lock after we acquire it..
59   std::unique_lock<std::recursive_mutex> guard(m_unwind_mutex);
60   guard.unlock();
61   if (frame_idx < m_pcs.size()) {
62     cfa = frame_idx;
63     pc = m_pcs[frame_idx];
64     if (m_pcs_are_call_addresses)
65       behaves_like_zeroth_frame = true;
66     else
67       behaves_like_zeroth_frame = (frame_idx == 0);
68     return true;
69   }
70   return false;
71 }
72 
73 uint32_t HistoryUnwind::DoGetFrameCount() { return m_pcs.size(); }
74