1 //===-- ThreadKDP.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 "ThreadKDP.h"
10 
11 #include "lldb/Host/SafeMachO.h"
12 
13 #include "lldb/Breakpoint/Watchpoint.h"
14 #include "lldb/Target/Process.h"
15 #include "lldb/Target/RegisterContext.h"
16 #include "lldb/Target/StopInfo.h"
17 #include "lldb/Target/Target.h"
18 #include "lldb/Target/Unwind.h"
19 #include "lldb/Utility/ArchSpec.h"
20 #include "lldb/Utility/DataExtractor.h"
21 #include "lldb/Utility/State.h"
22 #include "lldb/Utility/StreamString.h"
23 
24 #include "Plugins/Process/Utility/StopInfoMachException.h"
25 #include "ProcessKDP.h"
26 #include "ProcessKDPLog.h"
27 #include "RegisterContextKDP_arm.h"
28 #include "RegisterContextKDP_arm64.h"
29 #include "RegisterContextKDP_i386.h"
30 #include "RegisterContextKDP_x86_64.h"
31 
32 #include <memory>
33 
34 using namespace lldb;
35 using namespace lldb_private;
36 
37 //----------------------------------------------------------------------
38 // Thread Registers
39 //----------------------------------------------------------------------
40 
41 ThreadKDP::ThreadKDP(Process &process, lldb::tid_t tid)
42     : Thread(process, tid), m_thread_name(), m_dispatch_queue_name(),
43       m_thread_dispatch_qaddr(LLDB_INVALID_ADDRESS) {
44   Log *log = ProcessKDPLog::GetLogIfAllCategoriesSet(KDP_LOG_THREAD);
45   LLDB_LOG(log, "this = {0}, tid = {1:x}", this, GetID());
46 }
47 
48 ThreadKDP::~ThreadKDP() {
49   Log *log = ProcessKDPLog::GetLogIfAllCategoriesSet(KDP_LOG_THREAD);
50   LLDB_LOG(log, "this = {0}, tid = {1:x}", this, GetID());
51   DestroyThread();
52 }
53 
54 const char *ThreadKDP::GetName() {
55   if (m_thread_name.empty())
56     return nullptr;
57   return m_thread_name.c_str();
58 }
59 
60 const char *ThreadKDP::GetQueueName() { return nullptr; }
61 
62 void ThreadKDP::RefreshStateAfterStop() {
63   // Invalidate all registers in our register context. We don't set "force" to
64   // true because the stop reply packet might have had some register values
65   // that were expedited and these will already be copied into the register
66   // context by the time this function gets called. The KDPRegisterContext
67   // class has been made smart enough to detect when it needs to invalidate
68   // which registers are valid by putting hooks in the register read and
69   // register supply functions where they check the process stop ID and do the
70   // right thing.
71   const bool force = false;
72   lldb::RegisterContextSP reg_ctx_sp(GetRegisterContext());
73   if (reg_ctx_sp)
74     reg_ctx_sp->InvalidateIfNeeded(force);
75 }
76 
77 bool ThreadKDP::ThreadIDIsValid(lldb::tid_t thread) { return thread != 0; }
78 
79 void ThreadKDP::Dump(Log *log, uint32_t index) {}
80 
81 bool ThreadKDP::ShouldStop(bool &step_more) { return true; }
82 lldb::RegisterContextSP ThreadKDP::GetRegisterContext() {
83   if (!m_reg_context_sp)
84     m_reg_context_sp = CreateRegisterContextForFrame(nullptr);
85   return m_reg_context_sp;
86 }
87 
88 lldb::RegisterContextSP
89 ThreadKDP::CreateRegisterContextForFrame(StackFrame *frame) {
90   lldb::RegisterContextSP reg_ctx_sp;
91   uint32_t concrete_frame_idx = 0;
92 
93   if (frame)
94     concrete_frame_idx = frame->GetConcreteFrameIndex();
95 
96   if (concrete_frame_idx == 0) {
97     ProcessSP process_sp(CalculateProcess());
98     if (process_sp) {
99       switch (static_cast<ProcessKDP *>(process_sp.get())
100                   ->GetCommunication()
101                   .GetCPUType()) {
102       case llvm::MachO::CPU_TYPE_ARM:
103         reg_ctx_sp =
104             std::make_shared<RegisterContextKDP_arm>(*this, concrete_frame_idx);
105         break;
106       case llvm::MachO::CPU_TYPE_ARM64:
107         reg_ctx_sp = std::make_shared<RegisterContextKDP_arm64>(
108             *this, concrete_frame_idx);
109         break;
110       case llvm::MachO::CPU_TYPE_I386:
111         reg_ctx_sp = std::make_shared<RegisterContextKDP_i386>(
112             *this, concrete_frame_idx);
113         break;
114       case llvm::MachO::CPU_TYPE_X86_64:
115         reg_ctx_sp = std::make_shared<RegisterContextKDP_x86_64>(
116             *this, concrete_frame_idx);
117         break;
118       default:
119         llvm_unreachable("Add CPU type support in KDP");
120       }
121     }
122   } else {
123     Unwind *unwinder = GetUnwinder();
124     if (unwinder != nullptr)
125       reg_ctx_sp = unwinder->CreateRegisterContextForFrame(frame);
126   }
127   return reg_ctx_sp;
128 }
129 
130 bool ThreadKDP::CalculateStopInfo() {
131   ProcessSP process_sp(GetProcess());
132   if (process_sp) {
133     if (m_cached_stop_info_sp) {
134       SetStopInfo(m_cached_stop_info_sp);
135     } else {
136       SetStopInfo(StopInfo::CreateStopReasonWithSignal(*this, SIGSTOP));
137     }
138     return true;
139   }
140   return false;
141 }
142 
143 void ThreadKDP::SetStopInfoFrom_KDP_EXCEPTION(
144     const DataExtractor &exc_reply_packet) {
145   lldb::offset_t offset = 0;
146   uint8_t reply_command = exc_reply_packet.GetU8(&offset);
147   if (reply_command == CommunicationKDP::KDP_EXCEPTION) {
148     offset = 8;
149     const uint32_t count = exc_reply_packet.GetU32(&offset);
150     if (count >= 1) {
151       // const uint32_t cpu = exc_reply_packet.GetU32 (&offset);
152       offset += 4; // Skip the useless CPU field
153       const uint32_t exc_type = exc_reply_packet.GetU32(&offset);
154       const uint32_t exc_code = exc_reply_packet.GetU32(&offset);
155       const uint32_t exc_subcode = exc_reply_packet.GetU32(&offset);
156       // We have to make a copy of the stop info because the thread list will
157       // iterate through the threads and clear all stop infos..
158 
159       // Let the StopInfoMachException::CreateStopReasonWithMachException()
160       // function update the PC if needed as we might hit a software breakpoint
161       // and need to decrement the PC (i386 and x86_64 need this) and KDP
162       // doesn't do this for us.
163       const bool pc_already_adjusted = false;
164       const bool adjust_pc_if_needed = true;
165 
166       m_cached_stop_info_sp =
167           StopInfoMachException::CreateStopReasonWithMachException(
168               *this, exc_type, 2, exc_code, exc_subcode, 0, pc_already_adjusted,
169               adjust_pc_if_needed);
170     }
171   }
172 }
173