1 //===-- UserExpression.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/Host/Config.h"
10
11 #include <cstdio>
12 #if HAVE_SYS_TYPES_H
13 #include <sys/types.h>
14 #endif
15
16 #include <cstdlib>
17 #include <map>
18 #include <string>
19
20 #include "lldb/Core/Module.h"
21 #include "lldb/Core/StreamFile.h"
22 #include "lldb/Core/ValueObjectConstResult.h"
23 #include "lldb/Expression/DiagnosticManager.h"
24 #include "lldb/Expression/ExpressionVariable.h"
25 #include "lldb/Expression/IRExecutionUnit.h"
26 #include "lldb/Expression/IRInterpreter.h"
27 #include "lldb/Expression/Materializer.h"
28 #include "lldb/Expression/UserExpression.h"
29 #include "lldb/Host/HostInfo.h"
30 #include "lldb/Symbol/Block.h"
31 #include "lldb/Symbol/Function.h"
32 #include "lldb/Symbol/ObjectFile.h"
33 #include "lldb/Symbol/SymbolVendor.h"
34 #include "lldb/Symbol/Type.h"
35 #include "lldb/Symbol/TypeSystem.h"
36 #include "lldb/Symbol/VariableList.h"
37 #include "lldb/Target/ExecutionContext.h"
38 #include "lldb/Target/Process.h"
39 #include "lldb/Target/StackFrame.h"
40 #include "lldb/Target/Target.h"
41 #include "lldb/Target/ThreadPlan.h"
42 #include "lldb/Target/ThreadPlanCallUserExpression.h"
43 #include "lldb/Utility/ConstString.h"
44 #include "lldb/Utility/Log.h"
45 #include "lldb/Utility/StreamString.h"
46
47 using namespace lldb_private;
48
49 char UserExpression::ID;
50
UserExpression(ExecutionContextScope & exe_scope,llvm::StringRef expr,llvm::StringRef prefix,lldb::LanguageType language,ResultType desired_type,const EvaluateExpressionOptions & options)51 UserExpression::UserExpression(ExecutionContextScope &exe_scope,
52 llvm::StringRef expr, llvm::StringRef prefix,
53 lldb::LanguageType language,
54 ResultType desired_type,
55 const EvaluateExpressionOptions &options)
56 : Expression(exe_scope), m_expr_text(std::string(expr)),
57 m_expr_prefix(std::string(prefix)), m_language(language),
58 m_desired_type(desired_type), m_options(options) {}
59
60 UserExpression::~UserExpression() = default;
61
InstallContext(ExecutionContext & exe_ctx)62 void UserExpression::InstallContext(ExecutionContext &exe_ctx) {
63 m_jit_process_wp = exe_ctx.GetProcessSP();
64
65 lldb::StackFrameSP frame_sp = exe_ctx.GetFrameSP();
66
67 if (frame_sp)
68 m_address = frame_sp->GetFrameCodeAddress();
69 }
70
LockAndCheckContext(ExecutionContext & exe_ctx,lldb::TargetSP & target_sp,lldb::ProcessSP & process_sp,lldb::StackFrameSP & frame_sp)71 bool UserExpression::LockAndCheckContext(ExecutionContext &exe_ctx,
72 lldb::TargetSP &target_sp,
73 lldb::ProcessSP &process_sp,
74 lldb::StackFrameSP &frame_sp) {
75 lldb::ProcessSP expected_process_sp = m_jit_process_wp.lock();
76 process_sp = exe_ctx.GetProcessSP();
77
78 if (process_sp != expected_process_sp)
79 return false;
80
81 process_sp = exe_ctx.GetProcessSP();
82 target_sp = exe_ctx.GetTargetSP();
83 frame_sp = exe_ctx.GetFrameSP();
84
85 if (m_address.IsValid()) {
86 if (!frame_sp)
87 return false;
88 return (Address::CompareLoadAddress(m_address,
89 frame_sp->GetFrameCodeAddress(),
90 target_sp.get()) == 0);
91 }
92
93 return true;
94 }
95
MatchesContext(ExecutionContext & exe_ctx)96 bool UserExpression::MatchesContext(ExecutionContext &exe_ctx) {
97 lldb::TargetSP target_sp;
98 lldb::ProcessSP process_sp;
99 lldb::StackFrameSP frame_sp;
100
101 return LockAndCheckContext(exe_ctx, target_sp, process_sp, frame_sp);
102 }
103
GetObjectPointer(lldb::StackFrameSP frame_sp,ConstString & object_name,Status & err)104 lldb::addr_t UserExpression::GetObjectPointer(lldb::StackFrameSP frame_sp,
105 ConstString &object_name,
106 Status &err) {
107 err.Clear();
108
109 if (!frame_sp) {
110 err.SetErrorStringWithFormat(
111 "Couldn't load '%s' because the context is incomplete",
112 object_name.AsCString());
113 return LLDB_INVALID_ADDRESS;
114 }
115
116 lldb::VariableSP var_sp;
117 lldb::ValueObjectSP valobj_sp;
118
119 valobj_sp = frame_sp->GetValueForVariableExpressionPath(
120 object_name.GetStringRef(), lldb::eNoDynamicValues,
121 StackFrame::eExpressionPathOptionCheckPtrVsMember |
122 StackFrame::eExpressionPathOptionsNoFragileObjcIvar |
123 StackFrame::eExpressionPathOptionsNoSyntheticChildren |
124 StackFrame::eExpressionPathOptionsNoSyntheticArrayRange,
125 var_sp, err);
126
127 if (!err.Success() || !valobj_sp.get())
128 return LLDB_INVALID_ADDRESS;
129
130 lldb::addr_t ret = valobj_sp->GetValueAsUnsigned(LLDB_INVALID_ADDRESS);
131
132 if (ret == LLDB_INVALID_ADDRESS) {
133 err.SetErrorStringWithFormat(
134 "Couldn't load '%s' because its value couldn't be evaluated",
135 object_name.AsCString());
136 return LLDB_INVALID_ADDRESS;
137 }
138
139 return ret;
140 }
141
142 lldb::ExpressionResults
Evaluate(ExecutionContext & exe_ctx,const EvaluateExpressionOptions & options,llvm::StringRef expr,llvm::StringRef prefix,lldb::ValueObjectSP & result_valobj_sp,Status & error,std::string * fixed_expression,ValueObject * ctx_obj)143 UserExpression::Evaluate(ExecutionContext &exe_ctx,
144 const EvaluateExpressionOptions &options,
145 llvm::StringRef expr, llvm::StringRef prefix,
146 lldb::ValueObjectSP &result_valobj_sp, Status &error,
147 std::string *fixed_expression, ValueObject *ctx_obj) {
148 Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_EXPRESSIONS |
149 LIBLLDB_LOG_STEP));
150
151 if (ctx_obj) {
152 static unsigned const ctx_type_mask =
153 lldb::TypeFlags::eTypeIsClass | lldb::TypeFlags::eTypeIsStructUnion;
154 if (!(ctx_obj->GetTypeInfo() & ctx_type_mask)) {
155 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a context object of "
156 "an invalid type, can't run expressions.");
157 error.SetErrorString("a context object of an invalid type passed");
158 return lldb::eExpressionSetupError;
159 }
160 }
161
162 lldb_private::ExecutionPolicy execution_policy = options.GetExecutionPolicy();
163 lldb::LanguageType language = options.GetLanguage();
164 const ResultType desired_type = options.DoesCoerceToId()
165 ? UserExpression::eResultTypeId
166 : UserExpression::eResultTypeAny;
167 lldb::ExpressionResults execution_results = lldb::eExpressionSetupError;
168
169 Target *target = exe_ctx.GetTargetPtr();
170 if (!target) {
171 LLDB_LOG(log, "== [UserExpression::Evaluate] Passed a NULL target, can't "
172 "run expressions.");
173 error.SetErrorString("expression passed a null target");
174 return lldb::eExpressionSetupError;
175 }
176
177 Process *process = exe_ctx.GetProcessPtr();
178
179 if (process == nullptr || process->GetState() != lldb::eStateStopped) {
180 if (execution_policy == eExecutionPolicyAlways) {
181 LLDB_LOG(log, "== [UserExpression::Evaluate] Expression may not run, but "
182 "is not constant ==");
183
184 error.SetErrorString("expression needed to run but couldn't");
185
186 return execution_results;
187 }
188 }
189
190 // Explicitly force the IR interpreter to evaluate the expression when the
191 // there is no process that supports running the expression for us. Don't
192 // change the execution policy if we have the special top-level policy that
193 // doesn't contain any expression and there is nothing to interpret.
194 if (execution_policy != eExecutionPolicyTopLevel &&
195 (process == nullptr || !process->CanJIT()))
196 execution_policy = eExecutionPolicyNever;
197
198 // We need to set the expression execution thread here, turns out parse can
199 // call functions in the process of looking up symbols, which will escape the
200 // context set by exe_ctx passed to Execute.
201 lldb::ThreadSP thread_sp = exe_ctx.GetThreadSP();
202 ThreadList::ExpressionExecutionThreadPusher execution_thread_pusher(
203 thread_sp);
204
205 llvm::StringRef full_prefix;
206 llvm::StringRef option_prefix(options.GetPrefix());
207 std::string full_prefix_storage;
208 if (!prefix.empty() && !option_prefix.empty()) {
209 full_prefix_storage = std::string(prefix);
210 full_prefix_storage.append(std::string(option_prefix));
211 full_prefix = full_prefix_storage;
212 } else if (!prefix.empty())
213 full_prefix = prefix;
214 else
215 full_prefix = option_prefix;
216
217 // If the language was not specified in the expression command, set it to the
218 // language in the target's properties if specified, else default to the
219 // langage for the frame.
220 if (language == lldb::eLanguageTypeUnknown) {
221 if (target->GetLanguage() != lldb::eLanguageTypeUnknown)
222 language = target->GetLanguage();
223 else if (StackFrame *frame = exe_ctx.GetFramePtr())
224 language = frame->GetLanguage();
225 }
226
227 lldb::UserExpressionSP user_expression_sp(
228 target->GetUserExpressionForLanguage(expr, full_prefix, language,
229 desired_type, options, ctx_obj,
230 error));
231 if (error.Fail()) {
232 LLDB_LOG(log, "== [UserExpression::Evaluate] Getting expression: {0} ==",
233 error.AsCString());
234 return lldb::eExpressionSetupError;
235 }
236
237 LLDB_LOG(log, "== [UserExpression::Evaluate] Parsing expression {0} ==",
238 expr.str());
239
240 const bool keep_expression_in_memory = true;
241 const bool generate_debug_info = options.GetGenerateDebugInfo();
242
243 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationParse)) {
244 error.SetErrorString("expression interrupted by callback before parse");
245 result_valobj_sp = ValueObjectConstResult::Create(
246 exe_ctx.GetBestExecutionContextScope(), error);
247 return lldb::eExpressionInterrupted;
248 }
249
250 DiagnosticManager diagnostic_manager;
251
252 bool parse_success =
253 user_expression_sp->Parse(diagnostic_manager, exe_ctx, execution_policy,
254 keep_expression_in_memory, generate_debug_info);
255
256 // Calculate the fixed expression always, since we need it for errors.
257 std::string tmp_fixed_expression;
258 if (fixed_expression == nullptr)
259 fixed_expression = &tmp_fixed_expression;
260
261 const char *fixed_text = user_expression_sp->GetFixedText();
262 if (fixed_text != nullptr)
263 fixed_expression->append(fixed_text);
264
265 // If there is a fixed expression, try to parse it:
266 if (!parse_success) {
267 // Delete the expression that failed to parse before attempting to parse
268 // the next expression.
269 user_expression_sp.reset();
270
271 execution_results = lldb::eExpressionParseError;
272 if (fixed_expression && !fixed_expression->empty() &&
273 options.GetAutoApplyFixIts()) {
274 const uint64_t max_fix_retries = options.GetRetriesWithFixIts();
275 for (uint64_t i = 0; i < max_fix_retries; ++i) {
276 // Try parsing the fixed expression.
277 lldb::UserExpressionSP fixed_expression_sp(
278 target->GetUserExpressionForLanguage(
279 fixed_expression->c_str(), full_prefix, language, desired_type,
280 options, ctx_obj, error));
281 DiagnosticManager fixed_diagnostic_manager;
282 parse_success = fixed_expression_sp->Parse(
283 fixed_diagnostic_manager, exe_ctx, execution_policy,
284 keep_expression_in_memory, generate_debug_info);
285 if (parse_success) {
286 diagnostic_manager.Clear();
287 user_expression_sp = fixed_expression_sp;
288 break;
289 } else {
290 // The fixed expression also didn't parse. Let's check for any new
291 // Fix-Its we could try.
292 if (fixed_expression_sp->GetFixedText()) {
293 *fixed_expression = fixed_expression_sp->GetFixedText();
294 } else {
295 // Fixed expression didn't compile without a fixit, don't retry and
296 // don't tell the user about it.
297 fixed_expression->clear();
298 break;
299 }
300 }
301 }
302 }
303
304 if (!parse_success) {
305 std::string msg;
306 {
307 llvm::raw_string_ostream os(msg);
308 os << "expression failed to parse:\n";
309 if (!diagnostic_manager.Diagnostics().empty())
310 os << diagnostic_manager.GetString();
311 else
312 os << "unknown error";
313 if (target->GetEnableNotifyAboutFixIts() && fixed_expression &&
314 !fixed_expression->empty())
315 os << "\nfixed expression suggested:\n " << *fixed_expression;
316 }
317 error.SetExpressionError(execution_results, msg.c_str());
318 }
319 }
320
321 if (parse_success) {
322 lldb::ExpressionVariableSP expr_result;
323
324 if (execution_policy == eExecutionPolicyNever &&
325 !user_expression_sp->CanInterpret()) {
326 LLDB_LOG(log, "== [UserExpression::Evaluate] Expression may not run, but "
327 "is not constant ==");
328
329 if (!diagnostic_manager.Diagnostics().size())
330 error.SetExpressionError(lldb::eExpressionSetupError,
331 "expression needed to run but couldn't");
332 } else if (execution_policy == eExecutionPolicyTopLevel) {
333 error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric);
334 return lldb::eExpressionCompleted;
335 } else {
336 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationExecution)) {
337 error.SetExpressionError(
338 lldb::eExpressionInterrupted,
339 "expression interrupted by callback before execution");
340 result_valobj_sp = ValueObjectConstResult::Create(
341 exe_ctx.GetBestExecutionContextScope(), error);
342 return lldb::eExpressionInterrupted;
343 }
344
345 diagnostic_manager.Clear();
346
347 LLDB_LOG(log, "== [UserExpression::Evaluate] Executing expression ==");
348
349 execution_results =
350 user_expression_sp->Execute(diagnostic_manager, exe_ctx, options,
351 user_expression_sp, expr_result);
352
353 if (execution_results != lldb::eExpressionCompleted) {
354 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed "
355 "abnormally ==");
356
357 if (!diagnostic_manager.Diagnostics().size())
358 error.SetExpressionError(
359 execution_results, "expression failed to execute, unknown error");
360 else
361 error.SetExpressionError(execution_results,
362 diagnostic_manager.GetString().c_str());
363 } else {
364 if (expr_result) {
365 result_valobj_sp = expr_result->GetValueObject();
366 result_valobj_sp->SetPreferredDisplayLanguage(language);
367
368 LLDB_LOG(log,
369 "== [UserExpression::Evaluate] Execution completed "
370 "normally with result {0} ==",
371 result_valobj_sp->GetValueAsCString());
372 } else {
373 LLDB_LOG(log, "== [UserExpression::Evaluate] Execution completed "
374 "normally with no result ==");
375
376 error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric);
377 }
378 }
379 }
380 }
381
382 if (options.InvokeCancelCallback(lldb::eExpressionEvaluationComplete)) {
383 error.SetExpressionError(
384 lldb::eExpressionInterrupted,
385 "expression interrupted by callback after complete");
386 return lldb::eExpressionInterrupted;
387 }
388
389 if (result_valobj_sp.get() == nullptr) {
390 result_valobj_sp = ValueObjectConstResult::Create(
391 exe_ctx.GetBestExecutionContextScope(), error);
392 }
393
394 return execution_results;
395 }
396
397 lldb::ExpressionResults
Execute(DiagnosticManager & diagnostic_manager,ExecutionContext & exe_ctx,const EvaluateExpressionOptions & options,lldb::UserExpressionSP & shared_ptr_to_me,lldb::ExpressionVariableSP & result_var)398 UserExpression::Execute(DiagnosticManager &diagnostic_manager,
399 ExecutionContext &exe_ctx,
400 const EvaluateExpressionOptions &options,
401 lldb::UserExpressionSP &shared_ptr_to_me,
402 lldb::ExpressionVariableSP &result_var) {
403 lldb::ExpressionResults expr_result = DoExecute(
404 diagnostic_manager, exe_ctx, options, shared_ptr_to_me, result_var);
405 Target *target = exe_ctx.GetTargetPtr();
406 if (options.GetResultIsInternal() && result_var && target) {
407 if (auto *persistent_state =
408 target->GetPersistentExpressionStateForLanguage(m_language))
409 persistent_state->RemovePersistentVariable(result_var);
410 }
411 return expr_result;
412 }
413