1 //===-- ThreadPlanShouldStopHere.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/ThreadPlanShouldStopHere.h"
10 #include "lldb/Symbol/Symbol.h"
11 #include "lldb/Target/RegisterContext.h"
12 #include "lldb/Target/Thread.h"
13 #include "lldb/Utility/LLDBLog.h"
14 #include "lldb/Utility/Log.h"
15
16 using namespace lldb;
17 using namespace lldb_private;
18
19 // ThreadPlanShouldStopHere constructor
ThreadPlanShouldStopHere(ThreadPlan * owner)20 ThreadPlanShouldStopHere::ThreadPlanShouldStopHere(ThreadPlan *owner)
21 : m_callbacks(), m_baton(nullptr), m_owner(owner),
22 m_flags(ThreadPlanShouldStopHere::eNone) {
23 m_callbacks.should_stop_here_callback =
24 ThreadPlanShouldStopHere::DefaultShouldStopHereCallback;
25 m_callbacks.step_from_here_callback =
26 ThreadPlanShouldStopHere::DefaultStepFromHereCallback;
27 }
28
ThreadPlanShouldStopHere(ThreadPlan * owner,const ThreadPlanShouldStopHereCallbacks * callbacks,void * baton)29 ThreadPlanShouldStopHere::ThreadPlanShouldStopHere(
30 ThreadPlan *owner, const ThreadPlanShouldStopHereCallbacks *callbacks,
31 void *baton)
32 : m_callbacks(), m_baton(), m_owner(owner),
33 m_flags(ThreadPlanShouldStopHere::eNone) {
34 SetShouldStopHereCallbacks(callbacks, baton);
35 }
36
37 ThreadPlanShouldStopHere::~ThreadPlanShouldStopHere() = default;
38
InvokeShouldStopHereCallback(FrameComparison operation,Status & status)39 bool ThreadPlanShouldStopHere::InvokeShouldStopHereCallback(
40 FrameComparison operation, Status &status) {
41 bool should_stop_here = true;
42 if (m_callbacks.should_stop_here_callback) {
43 should_stop_here = m_callbacks.should_stop_here_callback(
44 m_owner, m_flags, operation, status, m_baton);
45 Log *log = GetLog(LLDBLog::Step);
46 if (log) {
47 lldb::addr_t current_addr =
48 m_owner->GetThread().GetRegisterContext()->GetPC(0);
49
50 LLDB_LOGF(log, "ShouldStopHere callback returned %u from 0x%" PRIx64 ".",
51 should_stop_here, current_addr);
52 }
53 }
54
55 return should_stop_here;
56 }
57
DefaultShouldStopHereCallback(ThreadPlan * current_plan,Flags & flags,FrameComparison operation,Status & status,void * baton)58 bool ThreadPlanShouldStopHere::DefaultShouldStopHereCallback(
59 ThreadPlan *current_plan, Flags &flags, FrameComparison operation,
60 Status &status, void *baton) {
61 bool should_stop_here = true;
62 StackFrame *frame = current_plan->GetThread().GetStackFrameAtIndex(0).get();
63 if (!frame)
64 return true;
65
66 Log *log = GetLog(LLDBLog::Step);
67
68 if ((operation == eFrameCompareOlder && flags.Test(eStepOutAvoidNoDebug)) ||
69 (operation == eFrameCompareYounger && flags.Test(eStepInAvoidNoDebug)) ||
70 (operation == eFrameCompareSameParent &&
71 flags.Test(eStepInAvoidNoDebug))) {
72 if (!frame->HasDebugInformation()) {
73 LLDB_LOGF(log, "Stepping out of frame with no debug info");
74
75 should_stop_here = false;
76 }
77 }
78
79 // Always avoid code with line number 0.
80 // FIXME: At present the ShouldStop and the StepFromHere calculate this
81 // independently. If this ever
82 // becomes expensive (this one isn't) we can try to have this set a state
83 // that the StepFromHere can use.
84 if (frame) {
85 SymbolContext sc;
86 sc = frame->GetSymbolContext(eSymbolContextLineEntry);
87 if (sc.line_entry.line == 0)
88 should_stop_here = false;
89 }
90
91 return should_stop_here;
92 }
93
DefaultStepFromHereCallback(ThreadPlan * current_plan,Flags & flags,FrameComparison operation,Status & status,void * baton)94 ThreadPlanSP ThreadPlanShouldStopHere::DefaultStepFromHereCallback(
95 ThreadPlan *current_plan, Flags &flags, FrameComparison operation,
96 Status &status, void *baton) {
97 const bool stop_others = false;
98 const size_t frame_index = 0;
99 ThreadPlanSP return_plan_sp;
100 // If we are stepping through code at line number 0, then we need to step
101 // over this range. Otherwise we will step out.
102 Log *log = GetLog(LLDBLog::Step);
103
104 StackFrame *frame = current_plan->GetThread().GetStackFrameAtIndex(0).get();
105 if (!frame)
106 return return_plan_sp;
107 SymbolContext sc;
108 sc = frame->GetSymbolContext(eSymbolContextLineEntry | eSymbolContextSymbol);
109
110 if (sc.line_entry.line == 0) {
111 AddressRange range = sc.line_entry.range;
112
113 // If the whole function is marked line 0 just step out, that's easier &
114 // faster than continuing to step through it.
115 bool just_step_out = false;
116 if (sc.symbol && sc.symbol->ValueIsAddress()) {
117 Address symbol_end = sc.symbol->GetAddress();
118 symbol_end.Slide(sc.symbol->GetByteSize() - 1);
119 if (range.ContainsFileAddress(sc.symbol->GetAddress()) &&
120 range.ContainsFileAddress(symbol_end)) {
121 LLDB_LOGF(log, "Stopped in a function with only line 0 lines, just "
122 "stepping out.");
123 just_step_out = true;
124 }
125 }
126 if (!just_step_out) {
127 LLDB_LOGF(log, "ThreadPlanShouldStopHere::DefaultStepFromHereCallback "
128 "Queueing StepInRange plan to step through line 0 code.");
129
130 return_plan_sp = current_plan->GetThread().QueueThreadPlanForStepInRange(
131 false, range, sc, nullptr, eOnlyDuringStepping, status,
132 eLazyBoolCalculate, eLazyBoolNo);
133 }
134 }
135
136 if (!return_plan_sp)
137 return_plan_sp =
138 current_plan->GetThread().QueueThreadPlanForStepOutNoShouldStop(
139 false, nullptr, true, stop_others, eVoteNo, eVoteNoOpinion,
140 frame_index, status, true);
141 return return_plan_sp;
142 }
143
QueueStepOutFromHerePlan(lldb_private::Flags & flags,lldb::FrameComparison operation,Status & status)144 ThreadPlanSP ThreadPlanShouldStopHere::QueueStepOutFromHerePlan(
145 lldb_private::Flags &flags, lldb::FrameComparison operation,
146 Status &status) {
147 ThreadPlanSP return_plan_sp;
148 if (m_callbacks.step_from_here_callback) {
149 return_plan_sp = m_callbacks.step_from_here_callback(
150 m_owner, flags, operation, status, m_baton);
151 }
152 return return_plan_sp;
153 }
154
CheckShouldStopHereAndQueueStepOut(lldb::FrameComparison operation,Status & status)155 lldb::ThreadPlanSP ThreadPlanShouldStopHere::CheckShouldStopHereAndQueueStepOut(
156 lldb::FrameComparison operation, Status &status) {
157 if (!InvokeShouldStopHereCallback(operation, status))
158 return QueueStepOutFromHerePlan(m_flags, operation, status);
159 else
160 return ThreadPlanSP();
161 }
162