LLDB mainline
CommandObjectDWIMPrint.cpp
Go to the documentation of this file.
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#include "llvm/Support/FormatVariadic.h"
27
28#include <regex>
29
30using namespace llvm;
31using namespace lldb;
32using namespace lldb_private;
33
35 : CommandObjectRaw(interpreter, "dwim-print",
36 "Print a variable or expression.",
37 "dwim-print [<variable-name> | <expression>]",
38 eCommandProcessMustBePaused | eCommandTryTargetAPILock) {
39
41 m_arguments.push_back({var_name_arg});
42
47 StringRef exclude_expr_options[] = {"debug", "top-level"};
48 m_option_group.Append(&m_expr_options, exclude_expr_options);
51}
52
54
55void CommandObjectDWIMPrint::DoExecute(StringRef command,
56 CommandReturnObject &result) {
58 OptionsWithRaw args{command};
59 StringRef expr = args.GetRawPart();
60
61 if (expr.empty()) {
62 result.AppendErrorWithFormatv("'{0}' takes a variable or expression",
64 return;
65 }
66
67 if (args.HasArgs()) {
68 if (!ParseOptionsAndNotify(args.GetArgs(), result, m_option_group,
69 m_exe_ctx))
70 return;
71 }
72
73 // If the user has not specified, default to disabling persistent results.
77
78 auto verbosity = GetDebugger().GetDWIMPrintVerbosity();
79
80 Target *target_ptr = m_exe_ctx.GetTargetPtr();
81 // Fallback to the dummy target, which can allow for expression evaluation.
82 Target &target = target_ptr ? *target_ptr : GetDummyTarget();
83
84 EvaluateExpressionOptions eval_options =
86 // This command manually removes the result variable, make sure expression
87 // evaluation doesn't do it first.
88 eval_options.SetSuppressPersistentResult(false);
89
92 dump_options.SetHideRootName(suppress_result);
93
94 bool is_po = m_varobj_options.use_objc;
95
97
98 // Either Swift was explicitly specified, or the frame is Swift.
100 if (language == lldb::eLanguageTypeUnknown && frame)
101 language = frame->GuessLanguage();
102
103 // Add a hint if object description was requested, but no description
104 // function was implemented.
105 auto maybe_add_hint = [&](llvm::StringRef output) {
106 // Identify the default output of object description for Swift and
107 // Objective-C
108 // "<Name: 0x...>. The regex is:
109 // - Start with "<".
110 // - Followed by 1 or more non-whitespace characters.
111 // - Followed by ": 0x".
112 // - Followed by 5 or more hex digits.
113 // - Followed by ">".
114 // - End with zero or more whitespace characters.
115 const std::regex swift_class_regex("^<\\S+: 0x[[:xdigit:]]{5,}>\\s*$");
116
117 if (GetDebugger().GetShowDontUsePoHint() && target_ptr &&
118 (language == lldb::eLanguageTypeSwift ||
119 language == lldb::eLanguageTypeObjC) &&
120 std::regex_match(output.data(), swift_class_regex)) {
121
122 static bool note_shown = false;
123 if (note_shown)
124 return;
125
126 result.GetOutputStream()
127 << "note: object description requested, but type doesn't implement "
128 "a custom object description. Consider using \"p\" instead of "
129 "\"po\" (this note will only be shown once per debug session).\n";
130 note_shown = true;
131 }
132 };
133
134 // First, try `expr` as the name of a frame variable.
135 if (frame) {
136 auto valobj_sp = frame->FindVariable(ConstString(expr));
137 if (valobj_sp && valobj_sp->GetError().Success()) {
138 if (!suppress_result) {
139 if (auto persisted_valobj = valobj_sp->Persist())
140 valobj_sp = persisted_valobj;
141 }
142
143 if (verbosity == eDWIMPrintVerbosityFull) {
144 StringRef flags;
145 if (args.HasArgs())
146 flags = args.GetArgString();
147 result.AppendMessageWithFormatv("note: ran `frame variable {0}{1}`",
148 flags, expr);
149 }
150
151 if (is_po) {
152 StreamString temp_result_stream;
153 valobj_sp->Dump(temp_result_stream, dump_options);
154 llvm::StringRef output = temp_result_stream.GetString();
155 maybe_add_hint(output);
156 result.GetOutputStream() << output;
157 } else {
158 valobj_sp->Dump(result.GetOutputStream(), dump_options);
159 }
161 return;
162 }
163 }
164
165 // Second, also lastly, try `expr` as a source expression to evaluate.
166 {
167 auto *exe_scope = m_exe_ctx.GetBestExecutionContextScope();
168 ValueObjectSP valobj_sp;
169 std::string fixed_expression;
170
171 ExpressionResults expr_result = target.EvaluateExpression(
172 expr, exe_scope, valobj_sp, eval_options, &fixed_expression);
173
174 // Only mention Fix-Its if the expression evaluator applied them.
175 // Compiler errors refer to the final expression after applying Fix-It(s).
176 if (!fixed_expression.empty() && target.GetEnableNotifyAboutFixIts()) {
177 Stream &error_stream = result.GetErrorStream();
178 error_stream << " Evaluated this expression after applying Fix-It(s):\n";
179 error_stream << " " << fixed_expression << "\n";
180 }
181
182 if (expr_result == eExpressionCompleted) {
183 if (verbosity != eDWIMPrintVerbosityNone) {
184 StringRef flags;
185 if (args.HasArgs())
186 flags = args.GetArgStringWithDelimiter();
187 result.AppendMessageWithFormatv("note: ran `expression {0}{1}`", flags,
188 expr);
189 }
190
191 if (valobj_sp->GetError().GetError() != UserExpression::kNoResult) {
192 if (is_po) {
193 StreamString temp_result_stream;
194 valobj_sp->Dump(temp_result_stream, dump_options);
195 llvm::StringRef output = temp_result_stream.GetString();
196 maybe_add_hint(output);
197 result.GetOutputStream() << output;
198 } else {
199 valobj_sp->Dump(result.GetOutputStream(), dump_options);
200 }
201 }
202
203 if (suppress_result)
204 if (auto result_var_sp =
205 target.GetPersistentVariable(valobj_sp->GetName())) {
206 auto language = valobj_sp->GetPreferredDisplayLanguage();
207 if (auto *persistent_state =
209 persistent_state->RemovePersistentVariable(result_var_sp);
210 }
211
213 } else {
214 if (valobj_sp)
215 result.SetError(valobj_sp->GetError());
216 else
218 "unknown error evaluating expression `{0}`", expr);
219 }
220 }
221}
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.
bool ParseOptionsAndNotify(Args &args, CommandReturnObject &result, OptionGroupOptions &group_options, ExecutionContext &exe_ctx)
ExecutionContext m_exe_ctx
std::vector< CommandArgumentEntry > m_arguments
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:590
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:42
lldb::LanguageType GuessLanguage()
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:4544
PersistentExpressionState * GetPersistentExpressionStateForLanguage(lldb::LanguageType language)
Definition: Target.cpp:2493
lldb::ExpressionVariableSP GetPersistentVariable(ConstString name)
Definition: Target.cpp:2735
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:2662
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: SBAttachInfo.h:14
Definition: SBAddress.h:15
std::shared_ptr< lldb_private::ValueObject > ValueObjectSP
Definition: lldb-forward.h:472
@ 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:53
Used to build individual command argument lists.
Definition: CommandObject.h:93