1//===-- ThreadPlanStepInstruction.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/Target/ThreadPlanStepInstruction.h"
10#include "lldb/Target/Process.h"
11#include "lldb/Target/RegisterContext.h"
12#include "lldb/Target/StopInfo.h"
13#include "lldb/Target/Target.h"
14#include "lldb/Utility/LLDBLog.h"
15#include "lldb/Utility/Log.h"
16#include "lldb/Utility/Stream.h"
17
18using namespace lldb;
19using namespace lldb_private;
20
21// ThreadPlanStepInstruction: Step over the current instruction
22
23ThreadPlanStepInstruction::ThreadPlanStepInstruction(Thread &thread,
24 bool step_over,
25 bool stop_other_threads,
26 Vote report_stop_vote,
27 Vote report_run_vote)
28 : ThreadPlan(ThreadPlan::eKindStepInstruction,
29 "Step over single instruction", thread, report_stop_vote,
30 report_run_vote),
31 m_instruction_addr(0), m_stop_other_threads(stop_other_threads),
32 m_step_over(step_over) {
33 m_takes_iteration_count = true;
34 SetUpState();
35}
36
37ThreadPlanStepInstruction::~ThreadPlanStepInstruction() = default;
38
39void ThreadPlanStepInstruction::SetUpState() {
40 Thread &thread = GetThread();
41 m_instruction_addr = thread.GetRegisterContext()->GetPC(fail_value: 0);
42 StackFrameSP start_frame_sp(thread.GetStackFrameAtIndex(idx: 0));
43 m_stack_id = start_frame_sp->GetStackID();
44
45 m_start_has_symbol =
46 start_frame_sp->GetSymbolContext(resolve_scope: eSymbolContextSymbol).symbol != nullptr;
47
48 StackFrameSP parent_frame_sp = thread.GetStackFrameAtIndex(idx: 1);
49 if (parent_frame_sp)
50 m_parent_frame_id = parent_frame_sp->GetStackID();
51}
52
53void ThreadPlanStepInstruction::GetDescription(Stream *s,
54 lldb::DescriptionLevel level) {
55 auto PrintFailureIfAny = [&]() {
56 if (m_status.Success())
57 return;
58 s->Printf(format: " failed (%s)", m_status.AsCString());
59 };
60
61 if (level == lldb::eDescriptionLevelBrief) {
62 if (m_step_over)
63 s->Printf(format: "instruction step over");
64 else
65 s->Printf(format: "instruction step into");
66
67 PrintFailureIfAny();
68 } else {
69 s->Printf(format: "Stepping one instruction past ");
70 DumpAddress(s&: s->AsRawOstream(), addr: m_instruction_addr, addr_size: sizeof(addr_t));
71 if (!m_start_has_symbol)
72 s->Printf(format: " which has no symbol");
73
74 if (m_step_over)
75 s->Printf(format: " stepping over calls");
76 else
77 s->Printf(format: " stepping into calls");
78
79 PrintFailureIfAny();
80 }
81}
82
83bool ThreadPlanStepInstruction::ValidatePlan(Stream *error) {
84 // Since we read the instruction we're stepping over from the thread, this
85 // plan will always work.
86 return true;
87}
88
89bool ThreadPlanStepInstruction::DoPlanExplainsStop(Event *event_ptr) {
90 StopInfoSP stop_info_sp = GetPrivateStopInfo();
91 if (stop_info_sp) {
92 StopReason reason = stop_info_sp->GetStopReason();
93 return (reason == eStopReasonTrace || reason == eStopReasonNone);
94 }
95 return false;
96}
97
98bool ThreadPlanStepInstruction::IsPlanStale() {
99 Log *log = GetLog(mask: LLDBLog::Step);
100 Thread &thread = GetThread();
101 StackID cur_frame_id = thread.GetStackFrameAtIndex(idx: 0)->GetStackID();
102 if (cur_frame_id == m_stack_id) {
103 // Set plan Complete when we reach next instruction
104 uint64_t pc = thread.GetRegisterContext()->GetPC(fail_value: 0);
105 uint32_t max_opcode_size =
106 GetTarget().GetArchitecture().GetMaximumOpcodeByteSize();
107 bool next_instruction_reached = (pc > m_instruction_addr) &&
108 (pc <= m_instruction_addr + max_opcode_size);
109 if (next_instruction_reached) {
110 SetPlanComplete();
111 }
112 return (thread.GetRegisterContext()->GetPC(fail_value: 0) != m_instruction_addr);
113 } else if (cur_frame_id < m_stack_id) {
114 // If the current frame is younger than the start frame and we are stepping
115 // over, then we need to continue, but if we are doing just one step, we're
116 // done.
117 return !m_step_over;
118 } else {
119 if (log) {
120 LLDB_LOGF(log,
121 "ThreadPlanStepInstruction::IsPlanStale - Current frame is "
122 "older than start frame, plan is stale.");
123 }
124 return true;
125 }
126}
127
128bool ThreadPlanStepInstruction::ShouldStop(Event *event_ptr) {
129 Thread &thread = GetThread();
130 if (m_step_over) {
131 Log *log = GetLog(mask: LLDBLog::Step);
132 StackFrameSP cur_frame_sp = thread.GetStackFrameAtIndex(idx: 0);
133 if (!cur_frame_sp) {
134 LLDB_LOGF(
135 log,
136 "ThreadPlanStepInstruction couldn't get the 0th frame, stopping.");
137 SetPlanComplete();
138 return true;
139 }
140
141 StackID cur_frame_zero_id = cur_frame_sp->GetStackID();
142
143 if (cur_frame_zero_id == m_stack_id || m_stack_id < cur_frame_zero_id) {
144 if (thread.GetRegisterContext()->GetPC(fail_value: 0) != m_instruction_addr) {
145 if (--m_iteration_count <= 0) {
146 SetPlanComplete();
147 return true;
148 } else {
149 // We are still stepping, reset the start pc, and in case we've
150 // stepped out, reset the current stack id.
151 SetUpState();
152 return false;
153 }
154 } else
155 return false;
156 } else {
157 // We've stepped in, step back out again:
158 StackFrame *return_frame = thread.GetStackFrameAtIndex(idx: 1).get();
159 if (return_frame) {
160 if (return_frame->GetStackID() != m_parent_frame_id ||
161 m_start_has_symbol) {
162 // next-instruction shouldn't step out of inlined functions. But we
163 // may have stepped into a real function that starts with an inlined
164 // function, and we do want to step out of that...
165
166 if (cur_frame_sp->IsInlined()) {
167 StackFrameSP parent_frame_sp =
168 thread.GetFrameWithStackID(stack_id: m_stack_id);
169
170 if (parent_frame_sp &&
171 parent_frame_sp->GetConcreteFrameIndex() ==
172 cur_frame_sp->GetConcreteFrameIndex()) {
173 SetPlanComplete();
174 if (log) {
175 LLDB_LOGF(log,
176 "Frame we stepped into is inlined into the frame "
177 "we were stepping from, stopping.");
178 }
179 return true;
180 }
181 }
182
183 if (log) {
184 StreamString s;
185 s.PutCString(cstr: "Stepped in to: ");
186 addr_t stop_addr =
187 thread.GetStackFrameAtIndex(idx: 0)->GetRegisterContext()->GetPC();
188 DumpAddress(s&: s.AsRawOstream(), addr: stop_addr,
189 addr_size: GetTarget().GetArchitecture().GetAddressByteSize());
190 s.PutCString(cstr: " stepping out to: ");
191 addr_t return_addr = return_frame->GetRegisterContext()->GetPC();
192 DumpAddress(s&: s.AsRawOstream(), addr: return_addr,
193 addr_size: GetTarget().GetArchitecture().GetAddressByteSize());
194 LLDB_LOGF(log, "%s.", s.GetData());
195 }
196
197 // StepInstruction should probably have the tri-state RunMode, but
198 // for now it is safer to run others.
199 const bool stop_others = false;
200 thread.QueueThreadPlanForStepOutNoShouldStop(
201 abort_other_plans: false, addr_context: nullptr, first_insn: true, stop_other_threads: stop_others, report_stop_vote: eVoteNo, report_run_vote: eVoteNoOpinion, frame_idx: 0,
202 status&: m_status);
203 return false;
204 } else {
205 if (log) {
206 log->PutCString(
207 cstr: "The stack id we are stepping in changed, but our parent frame "
208 "did not when stepping from code with no symbols. "
209 "We are probably just confused about where we are, stopping.");
210 }
211 SetPlanComplete();
212 return true;
213 }
214 } else {
215 LLDB_LOGF(log, "Could not find previous frame, stopping.");
216 SetPlanComplete();
217 return true;
218 }
219 }
220 } else {
221 lldb::addr_t pc_addr = thread.GetRegisterContext()->GetPC(fail_value: 0);
222 if (pc_addr != m_instruction_addr) {
223 if (--m_iteration_count <= 0) {
224 SetPlanComplete();
225 return true;
226 } else {
227 // We are still stepping, reset the start pc, and in case we've stepped
228 // in or out, reset the current stack id.
229 SetUpState();
230 return false;
231 }
232 } else
233 return false;
234 }
235}
236
237bool ThreadPlanStepInstruction::StopOthers() { return m_stop_other_threads; }
238
239StateType ThreadPlanStepInstruction::GetPlanRunState() {
240 return eStateStepping;
241}
242
243bool ThreadPlanStepInstruction::WillStop() { return true; }
244
245bool ThreadPlanStepInstruction::MischiefManaged() {
246 if (IsPlanComplete()) {
247 Log *log = GetLog(mask: LLDBLog::Step);
248 LLDB_LOGF(log, "Completed single instruction step plan.");
249 ThreadPlan::MischiefManaged();
250 return true;
251 } else {
252 return false;
253 }
254}
255

source code of lldb/source/Target/ThreadPlanStepInstruction.cpp