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CommandObjectDWIMPrint.cpp
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1//===-- CommandObjectDWIMPrint.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
10
22#include "lldb/lldb-defines.h"
24#include "lldb/lldb-forward.h"
25#include "llvm/ADT/StringRef.h"
26
27#include <regex>
28
29using namespace llvm;
30using namespace lldb;
31using namespace lldb_private;
32
34 : CommandObjectRaw(interpreter, "dwim-print",
35 "Print a variable or expression.",
36 "dwim-print [<variable-name> | <expression>]",
37 eCommandProcessMustBePaused | eCommandTryTargetAPILock) {
38
40
45 StringRef exclude_expr_options[] = {"debug", "top-level"};
46 m_option_group.Append(&m_expr_options, exclude_expr_options);
49}
50
52
53void CommandObjectDWIMPrint::DoExecute(StringRef command,
54 CommandReturnObject &result) {
56 OptionsWithRaw args{command};
57 StringRef expr = args.GetRawPart();
58
59 if (expr.empty()) {
60 result.AppendErrorWithFormatv("'{0}' takes a variable or expression",
62 return;
63 }
64
65 if (args.HasArgs()) {
66 if (!ParseOptionsAndNotify(args.GetArgs(), result, m_option_group,
67 m_exe_ctx))
68 return;
69 }
70
71 // If the user has not specified, default to disabling persistent results.
75
76 auto verbosity = GetDebugger().GetDWIMPrintVerbosity();
77
78 Target *target_ptr = m_exe_ctx.GetTargetPtr();
79 // Fallback to the dummy target, which can allow for expression evaluation.
80 Target &target = target_ptr ? *target_ptr : GetDummyTarget();
81
82 EvaluateExpressionOptions eval_options =
84 // This command manually removes the result variable, make sure expression
85 // evaluation doesn't do it first.
86 eval_options.SetSuppressPersistentResult(false);
87
90 dump_options.SetHideRootName(suppress_result);
91
92 bool is_po = m_varobj_options.use_objc;
93
95
96 // Either the language was explicitly specified, or we check the frame.
98 if (language == lldb::eLanguageTypeUnknown && frame)
99 language = frame->GuessLanguage().AsLanguageType();
100
101 // Add a hint if object description was requested, but no description
102 // function was implemented.
103 auto maybe_add_hint = [&](llvm::StringRef output) {
104 // Identify the default output of object description for Swift and
105 // Objective-C
106 // "<Name: 0x...>. The regex is:
107 // - Start with "<".
108 // - Followed by 1 or more non-whitespace characters.
109 // - Followed by ": 0x".
110 // - Followed by 5 or more hex digits.
111 // - Followed by ">".
112 // - End with zero or more whitespace characters.
113 const std::regex swift_class_regex("^<\\S+: 0x[[:xdigit:]]{5,}>\\s*$");
114
115 if (GetDebugger().GetShowDontUsePoHint() && target_ptr &&
116 (language == lldb::eLanguageTypeSwift ||
117 language == lldb::eLanguageTypeObjC) &&
118 std::regex_match(output.data(), swift_class_regex)) {
119
120 static bool note_shown = false;
121 if (note_shown)
122 return;
123
124 result.GetOutputStream()
125 << "note: object description requested, but type doesn't implement "
126 "a custom object description. Consider using \"p\" instead of "
127 "\"po\" (this note will only be shown once per debug session).\n";
128 note_shown = true;
129 }
130 };
131
132 // Dump `valobj` according to whether `po` was requested or not.
133 auto dump_val_object = [&](ValueObject &valobj) {
134 if (is_po) {
135 StreamString temp_result_stream;
136 valobj.Dump(temp_result_stream, dump_options);
137 llvm::StringRef output = temp_result_stream.GetString();
138 maybe_add_hint(output);
139 result.GetOutputStream() << output;
140 } else {
141 valobj.Dump(result.GetOutputStream(), dump_options);
142 }
143 };
144
145 // First, try `expr` as the name of a frame variable.
146 if (frame) {
147 auto valobj_sp = frame->FindVariable(ConstString(expr));
148 if (valobj_sp && valobj_sp->GetError().Success()) {
149 if (!suppress_result) {
150 if (auto persisted_valobj = valobj_sp->Persist())
151 valobj_sp = persisted_valobj;
152 }
153
154 if (verbosity == eDWIMPrintVerbosityFull) {
155 StringRef flags;
156 if (args.HasArgs())
157 flags = args.GetArgString();
158 result.AppendMessageWithFormatv("note: ran `frame variable {0}{1}`",
159 flags, expr);
160 }
161
162 dump_val_object(*valobj_sp);
164 return;
165 }
166 }
167
168 // Second, try `expr` as a persistent variable.
169 if (expr.starts_with("$"))
170 if (auto *state = target.GetPersistentExpressionStateForLanguage(language))
171 if (auto var_sp = state->GetVariable(expr))
172 if (auto valobj_sp = var_sp->GetValueObject()) {
173 dump_val_object(*valobj_sp);
175 return;
176 }
177
178 // Third, and lastly, try `expr` as a source expression to evaluate.
179 {
180 auto *exe_scope = m_exe_ctx.GetBestExecutionContextScope();
181 ValueObjectSP valobj_sp;
182 std::string fixed_expression;
183
184 ExpressionResults expr_result = target.EvaluateExpression(
185 expr, exe_scope, valobj_sp, eval_options, &fixed_expression);
186
187 // Only mention Fix-Its if the expression evaluator applied them.
188 // Compiler errors refer to the final expression after applying Fix-It(s).
189 if (!fixed_expression.empty() && target.GetEnableNotifyAboutFixIts()) {
190 Stream &error_stream = result.GetErrorStream();
191 error_stream << " Evaluated this expression after applying Fix-It(s):\n";
192 error_stream << " " << fixed_expression << "\n";
193 }
194
195 if (expr_result == eExpressionCompleted) {
196 if (verbosity != eDWIMPrintVerbosityNone) {
197 StringRef flags;
198 if (args.HasArgs())
199 flags = args.GetArgStringWithDelimiter();
200 result.AppendMessageWithFormatv("note: ran `expression {0}{1}`", flags,
201 expr);
202 }
203
204 if (valobj_sp->GetError().GetError() != UserExpression::kNoResult)
205 dump_val_object(*valobj_sp);
206
207 if (suppress_result)
208 if (auto result_var_sp =
209 target.GetPersistentVariable(valobj_sp->GetName())) {
210 auto language = valobj_sp->GetPreferredDisplayLanguage();
211 if (auto *persistent_state =
213 persistent_state->RemovePersistentVariable(result_var_sp);
214 }
215
217 } else {
218 if (valobj_sp)
219 result.SetError(valobj_sp->GetError());
220 else
222 "unknown error evaluating expression `{0}`", expr);
223 }
224 }
225}
CommandObjectExpression::CommandOptions m_expr_options
CommandObjectDWIMPrint(CommandInterpreter &interpreter)
OptionGroupValueObjectDisplay m_varobj_options
void DoExecute(llvm::StringRef command, CommandReturnObject &result) override
bool ShouldSuppressResult(const OptionGroupValueObjectDisplay &display_opts) const
LanguageRuntimeDescriptionDisplayVerbosity m_verbosity
EvaluateExpressionOptions GetEvaluateExpressionOptions(const Target &target, const OptionGroupValueObjectDisplay &display_opts)
Return the appropriate expression options used for evaluating the expression in the given target.
void AddSimpleArgumentList(lldb::CommandArgumentType arg_type, ArgumentRepetitionType repetition_type=eArgRepeatPlain)
bool ParseOptionsAndNotify(Args &args, CommandReturnObject &result, OptionGroupOptions &group_options, ExecutionContext &exe_ctx)
ExecutionContext m_exe_ctx
void AppendErrorWithFormatv(const char *format, Args &&... args)
void SetStatus(lldb::ReturnStatus status)
void void AppendMessageWithFormatv(const char *format, Args &&... args)
void SetError(const Status &error, const char *fallback_error_cstr=nullptr)
A uniqued constant string class.
Definition: ConstString.h:40
lldb::DWIMPrintVerbosity GetDWIMPrintVerbosity() const
Definition: Debugger.cpp:591
DumpValueObjectOptions & SetHideRootName(bool hide_root_name)
ExecutionContextScope * GetBestExecutionContextScope() const
StackFrame * GetFramePtr() const
Returns a pointer to the frame object.
Target * GetTargetPtr() const
Returns a pointer to the target object.
static const uint32_t OPTION_GROUP_GDB_FMT
static const uint32_t OPTION_GROUP_FORMAT
void Append(OptionGroup *group)
Append options from a OptionGroup class.
Definition: Options.cpp:755
DumpValueObjectOptions GetAsDumpOptions(LanguageRuntimeDescriptionDisplayVerbosity lang_descr_verbosity=eLanguageRuntimeDescriptionDisplayVerbosityFull, lldb::Format format=lldb::eFormatDefault, lldb::TypeSummaryImplSP summary_sp=lldb::TypeSummaryImplSP())
A pair of an option list with a 'raw' string as a suffix.
Definition: Args.h:315
const std::string & GetRawPart() const
Returns the raw suffix part of the parsed string.
Definition: Args.h:364
A command line option parsing protocol class.
Definition: Options.h:58
void NotifyOptionParsingStarting(ExecutionContext *execution_context)
Definition: Options.cpp:33
This base class provides an interface to stack frames.
Definition: StackFrame.h:43
SourceLanguage GuessLanguage()
Similar to GetLanguage(), but is allowed to take a potentially incorrect guess if exact information i...
lldb::ValueObjectSP FindVariable(ConstString name)
Attempt to reconstruct the ValueObject for a variable with a given name from within the current Stack...
llvm::StringRef GetString() const
A stream class that can stream formatted output to a file.
Definition: Stream.h:28
bool GetEnableNotifyAboutFixIts() const
Definition: Target.cpp:4523
PersistentExpressionState * GetPersistentExpressionStateForLanguage(lldb::LanguageType language)
Definition: Target.cpp:2484
lldb::ExpressionVariableSP GetPersistentVariable(ConstString name)
Definition: Target.cpp:2723
lldb::ExpressionResults EvaluateExpression(llvm::StringRef expression, ExecutionContextScope *exe_scope, lldb::ValueObjectSP &result_valobj_sp, const EvaluateExpressionOptions &options=EvaluateExpressionOptions(), std::string *fixed_expression=nullptr, ValueObject *ctx_obj=nullptr)
Definition: Target.cpp:2650
static const Status::ValueType kNoResult
ValueObject::GetError() returns this if there is no result from the expression.
#define LLDB_OPT_SET_1
Definition: lldb-defines.h:111
#define LLDB_OPT_SET_ALL
Definition: lldb-defines.h:110
A class that represents a running process on the host machine.
Definition: SBAddress.h:15
std::shared_ptr< lldb_private::ValueObject > ValueObjectSP
Definition: lldb-forward.h:475
@ eDWIMPrintVerbosityFull
Always print a message indicating how dwim-print is evaluating its expression.
@ eDWIMPrintVerbosityNone
Run dwim-print with no verbosity.
LanguageType
Programming language type.
@ eLanguageTypeUnknown
Unknown or invalid language value.
@ eLanguageTypeSwift
Swift.
@ eLanguageTypeObjC
Objective-C.
ExpressionResults
The results of expression evaluation.
@ eExpressionCompleted
@ eReturnStatusSuccessFinishResult
Definition: Debugger.h:54
lldb::LanguageType AsLanguageType() const
Definition: Language.cpp:546