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