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