1 //===-- UserExpression.cpp ---------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include <stdio.h>
11 #if HAVE_SYS_TYPES_H
12 #include <sys/types.h>
13 #endif
14 
15 #include <cstdlib>
16 #include <map>
17 #include <string>
18 
19 #include "Plugins/ExpressionParser/Clang/ClangPersistentVariables.h"
20 #include "lldb/Core/Log.h"
21 #include "lldb/Core/Module.h"
22 #include "lldb/Core/StreamFile.h"
23 #include "lldb/Core/ValueObjectConstResult.h"
24 #include "lldb/Expression/DiagnosticManager.h"
25 #include "lldb/Expression/ExpressionSourceCode.h"
26 #include "lldb/Expression/IRExecutionUnit.h"
27 #include "lldb/Expression/IRInterpreter.h"
28 #include "lldb/Expression/Materializer.h"
29 #include "lldb/Expression/UserExpression.h"
30 #include "lldb/Host/HostInfo.h"
31 #include "lldb/Symbol/Block.h"
32 #include "lldb/Symbol/Function.h"
33 #include "lldb/Symbol/ObjectFile.h"
34 #include "lldb/Symbol/SymbolVendor.h"
35 #include "lldb/Symbol/Type.h"
36 #include "lldb/Symbol/TypeSystem.h"
37 #include "lldb/Symbol/VariableList.h"
38 #include "lldb/Target/ExecutionContext.h"
39 #include "lldb/Target/Process.h"
40 #include "lldb/Target/StackFrame.h"
41 #include "lldb/Target/Target.h"
42 #include "lldb/Target/ThreadPlan.h"
43 #include "lldb/Target/ThreadPlanCallUserExpression.h"
44 #include "lldb/Utility/ConstString.h"
45 #include "lldb/Utility/StreamString.h"
46 
47 using namespace lldb_private;
48 
49 UserExpression::UserExpression(ExecutionContextScope &exe_scope,
50                                llvm::StringRef expr, llvm::StringRef prefix,
51                                lldb::LanguageType language,
52                                ResultType desired_type,
53                                const EvaluateExpressionOptions &options)
54     : Expression(exe_scope), m_expr_text(expr), m_expr_prefix(prefix),
55       m_language(language), m_desired_type(desired_type), m_options(options) {}
56 
57 UserExpression::~UserExpression() {}
58 
59 void UserExpression::InstallContext(ExecutionContext &exe_ctx) {
60   m_jit_process_wp = exe_ctx.GetProcessSP();
61 
62   lldb::StackFrameSP frame_sp = exe_ctx.GetFrameSP();
63 
64   if (frame_sp)
65     m_address = frame_sp->GetFrameCodeAddress();
66 }
67 
68 bool UserExpression::LockAndCheckContext(ExecutionContext &exe_ctx,
69                                          lldb::TargetSP &target_sp,
70                                          lldb::ProcessSP &process_sp,
71                                          lldb::StackFrameSP &frame_sp) {
72   lldb::ProcessSP expected_process_sp = m_jit_process_wp.lock();
73   process_sp = exe_ctx.GetProcessSP();
74 
75   if (process_sp != expected_process_sp)
76     return false;
77 
78   process_sp = exe_ctx.GetProcessSP();
79   target_sp = exe_ctx.GetTargetSP();
80   frame_sp = exe_ctx.GetFrameSP();
81 
82   if (m_address.IsValid()) {
83     if (!frame_sp)
84       return false;
85     else
86       return (0 == Address::CompareLoadAddress(m_address,
87                                                frame_sp->GetFrameCodeAddress(),
88                                                target_sp.get()));
89   }
90 
91   return true;
92 }
93 
94 bool UserExpression::MatchesContext(ExecutionContext &exe_ctx) {
95   lldb::TargetSP target_sp;
96   lldb::ProcessSP process_sp;
97   lldb::StackFrameSP frame_sp;
98 
99   return LockAndCheckContext(exe_ctx, target_sp, process_sp, frame_sp);
100 }
101 
102 lldb::addr_t UserExpression::GetObjectPointer(lldb::StackFrameSP frame_sp,
103                                               ConstString &object_name,
104                                               Error &err) {
105   err.Clear();
106 
107   if (!frame_sp) {
108     err.SetErrorStringWithFormat(
109         "Couldn't load '%s' because the context is incomplete",
110         object_name.AsCString());
111     return LLDB_INVALID_ADDRESS;
112   }
113 
114   lldb::VariableSP var_sp;
115   lldb::ValueObjectSP valobj_sp;
116 
117   valobj_sp = frame_sp->GetValueForVariableExpressionPath(
118       object_name.AsCString(), lldb::eNoDynamicValues,
119       StackFrame::eExpressionPathOptionCheckPtrVsMember |
120           StackFrame::eExpressionPathOptionsNoFragileObjcIvar |
121           StackFrame::eExpressionPathOptionsNoSyntheticChildren |
122           StackFrame::eExpressionPathOptionsNoSyntheticArrayRange,
123       var_sp, err);
124 
125   if (!err.Success() || !valobj_sp.get())
126     return LLDB_INVALID_ADDRESS;
127 
128   lldb::addr_t ret = valobj_sp->GetValueAsUnsigned(LLDB_INVALID_ADDRESS);
129 
130   if (ret == LLDB_INVALID_ADDRESS) {
131     err.SetErrorStringWithFormat(
132         "Couldn't load '%s' because its value couldn't be evaluated",
133         object_name.AsCString());
134     return LLDB_INVALID_ADDRESS;
135   }
136 
137   return ret;
138 }
139 
140 lldb::ExpressionResults UserExpression::Evaluate(
141     ExecutionContext &exe_ctx, const EvaluateExpressionOptions &options,
142     llvm::StringRef expr, llvm::StringRef prefix,
143     lldb::ValueObjectSP &result_valobj_sp, Error &error, uint32_t line_offset,
144     std::string *fixed_expression, lldb::ModuleSP *jit_module_sp_ptr) {
145   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_EXPRESSIONS |
146                                                   LIBLLDB_LOG_STEP));
147 
148   lldb_private::ExecutionPolicy execution_policy = options.GetExecutionPolicy();
149   lldb::LanguageType language = options.GetLanguage();
150   const ResultType desired_type = options.DoesCoerceToId()
151                                       ? UserExpression::eResultTypeId
152                                       : UserExpression::eResultTypeAny;
153   lldb::ExpressionResults execution_results = lldb::eExpressionSetupError;
154 
155   Target *target = exe_ctx.GetTargetPtr();
156   if (!target) {
157     if (log)
158       log->Printf("== [UserExpression::Evaluate] Passed a NULL target, can't "
159                   "run expressions.");
160     error.SetErrorString("expression passed a null target");
161     return lldb::eExpressionSetupError;
162   }
163 
164   Process *process = exe_ctx.GetProcessPtr();
165 
166   if (process == NULL || process->GetState() != lldb::eStateStopped) {
167     if (execution_policy == eExecutionPolicyAlways) {
168       if (log)
169         log->Printf("== [UserExpression::Evaluate] Expression may not run, but "
170                     "is not constant ==");
171 
172       error.SetErrorString("expression needed to run but couldn't");
173 
174       return execution_results;
175     }
176   }
177 
178   if (process == NULL || !process->CanJIT())
179     execution_policy = eExecutionPolicyNever;
180 
181   // We need to set the expression execution thread here, turns out parse can
182   // call functions in the process of
183   // looking up symbols, which will escape the context set by exe_ctx passed to
184   // Execute.
185   lldb::ThreadSP thread_sp = exe_ctx.GetThreadSP();
186   ThreadList::ExpressionExecutionThreadPusher execution_thread_pusher(
187       thread_sp);
188 
189   llvm::StringRef full_prefix;
190   llvm::StringRef option_prefix(options.GetPrefix());
191   std::string full_prefix_storage;
192   if (!prefix.empty() && !option_prefix.empty()) {
193     full_prefix_storage = prefix;
194     full_prefix_storage.append(option_prefix);
195     full_prefix = full_prefix_storage;
196   } else if (!prefix.empty())
197     full_prefix = prefix;
198   else
199     full_prefix = option_prefix;
200 
201   // If the language was not specified in the expression command,
202   // set it to the language in the target's properties if
203   // specified, else default to the langage for the frame.
204   if (language == lldb::eLanguageTypeUnknown) {
205     if (target->GetLanguage() != lldb::eLanguageTypeUnknown)
206       language = target->GetLanguage();
207     else if (StackFrame *frame = exe_ctx.GetFramePtr())
208       language = frame->GetLanguage();
209   }
210 
211   lldb::UserExpressionSP user_expression_sp(
212       target->GetUserExpressionForLanguage(expr, full_prefix, language,
213                                            desired_type, options, error));
214   if (error.Fail()) {
215     if (log)
216       log->Printf("== [UserExpression::Evaluate] Getting expression: %s ==",
217                   error.AsCString());
218     return lldb::eExpressionSetupError;
219   }
220 
221   if (log)
222     log->Printf("== [UserExpression::Evaluate] Parsing expression %s ==",
223                 expr.str().c_str());
224 
225   const bool keep_expression_in_memory = true;
226   const bool generate_debug_info = options.GetGenerateDebugInfo();
227 
228   if (options.InvokeCancelCallback(lldb::eExpressionEvaluationParse)) {
229     error.SetErrorString("expression interrupted by callback before parse");
230     result_valobj_sp = ValueObjectConstResult::Create(
231         exe_ctx.GetBestExecutionContextScope(), error);
232     return lldb::eExpressionInterrupted;
233   }
234 
235   DiagnosticManager diagnostic_manager;
236 
237   bool parse_success =
238       user_expression_sp->Parse(diagnostic_manager, exe_ctx, execution_policy,
239                                 keep_expression_in_memory, generate_debug_info);
240 
241   // Calculate the fixed expression always, since we need it for errors.
242   std::string tmp_fixed_expression;
243   if (fixed_expression == nullptr)
244     fixed_expression = &tmp_fixed_expression;
245 
246   const char *fixed_text = user_expression_sp->GetFixedText();
247   if (fixed_text != nullptr)
248     fixed_expression->append(fixed_text);
249 
250   // If there is a fixed expression, try to parse it:
251   if (!parse_success) {
252     execution_results = lldb::eExpressionParseError;
253     if (fixed_expression && !fixed_expression->empty() &&
254         options.GetAutoApplyFixIts()) {
255       lldb::UserExpressionSP fixed_expression_sp(
256           target->GetUserExpressionForLanguage(fixed_expression->c_str(),
257                                                full_prefix, language,
258                                                desired_type, options, error));
259       DiagnosticManager fixed_diagnostic_manager;
260       parse_success = fixed_expression_sp->Parse(
261           fixed_diagnostic_manager, exe_ctx, execution_policy,
262           keep_expression_in_memory, generate_debug_info);
263       if (parse_success) {
264         diagnostic_manager.Clear();
265         user_expression_sp = fixed_expression_sp;
266       } else {
267         // If the fixed expression failed to parse, don't tell the user about,
268         // that won't help.
269         fixed_expression->clear();
270       }
271     }
272 
273     if (!parse_success) {
274       if (!fixed_expression->empty() && target->GetEnableNotifyAboutFixIts()) {
275         error.SetExpressionErrorWithFormat(
276             execution_results,
277             "expression failed to parse, fixed expression suggested:\n  %s",
278             fixed_expression->c_str());
279       } else {
280         if (!diagnostic_manager.Diagnostics().size())
281           error.SetExpressionError(execution_results,
282                                    "expression failed to parse, unknown error");
283         else
284           error.SetExpressionError(execution_results,
285                                    diagnostic_manager.GetString().c_str());
286       }
287     }
288   }
289 
290   if (parse_success) {
291     // If a pointer to a lldb::ModuleSP was passed in, return the JIT'ed module
292     // if one was created
293     if (jit_module_sp_ptr)
294       *jit_module_sp_ptr = user_expression_sp->GetJITModule();
295 
296     lldb::ExpressionVariableSP expr_result;
297 
298     if (execution_policy == eExecutionPolicyNever &&
299         !user_expression_sp->CanInterpret()) {
300       if (log)
301         log->Printf("== [UserExpression::Evaluate] Expression may not run, but "
302                     "is not constant ==");
303 
304       if (!diagnostic_manager.Diagnostics().size())
305         error.SetExpressionError(lldb::eExpressionSetupError,
306                                  "expression needed to run but couldn't");
307     } else if (execution_policy == eExecutionPolicyTopLevel) {
308       error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric);
309       return lldb::eExpressionCompleted;
310     } else {
311       if (options.InvokeCancelCallback(lldb::eExpressionEvaluationExecution)) {
312         error.SetExpressionError(
313             lldb::eExpressionInterrupted,
314             "expression interrupted by callback before execution");
315         result_valobj_sp = ValueObjectConstResult::Create(
316             exe_ctx.GetBestExecutionContextScope(), error);
317         return lldb::eExpressionInterrupted;
318       }
319 
320       diagnostic_manager.Clear();
321 
322       if (log)
323         log->Printf("== [UserExpression::Evaluate] Executing expression ==");
324 
325       execution_results =
326           user_expression_sp->Execute(diagnostic_manager, exe_ctx, options,
327                                       user_expression_sp, expr_result);
328 
329       if (execution_results != lldb::eExpressionCompleted) {
330         if (log)
331           log->Printf("== [UserExpression::Evaluate] Execution completed "
332                       "abnormally ==");
333 
334         if (!diagnostic_manager.Diagnostics().size())
335           error.SetExpressionError(
336               execution_results, "expression failed to execute, unknown error");
337         else
338           error.SetExpressionError(execution_results,
339                                    diagnostic_manager.GetString().c_str());
340       } else {
341         if (expr_result) {
342           result_valobj_sp = expr_result->GetValueObject();
343 
344           if (log)
345             log->Printf("== [UserExpression::Evaluate] Execution completed "
346                         "normally with result %s ==",
347                         result_valobj_sp->GetValueAsCString());
348         } else {
349           if (log)
350             log->Printf("== [UserExpression::Evaluate] Execution completed "
351                         "normally with no result ==");
352 
353           error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric);
354         }
355       }
356     }
357   }
358 
359   if (options.InvokeCancelCallback(lldb::eExpressionEvaluationComplete)) {
360     error.SetExpressionError(
361         lldb::eExpressionInterrupted,
362         "expression interrupted by callback after complete");
363     return lldb::eExpressionInterrupted;
364   }
365 
366   if (result_valobj_sp.get() == NULL) {
367     result_valobj_sp = ValueObjectConstResult::Create(
368         exe_ctx.GetBestExecutionContextScope(), error);
369   }
370 
371   return execution_results;
372 }
373 
374 lldb::ExpressionResults
375 UserExpression::Execute(DiagnosticManager &diagnostic_manager,
376                         ExecutionContext &exe_ctx,
377                         const EvaluateExpressionOptions &options,
378                         lldb::UserExpressionSP &shared_ptr_to_me,
379                         lldb::ExpressionVariableSP &result_var) {
380   lldb::ExpressionResults expr_result = DoExecute(
381       diagnostic_manager, exe_ctx, options, shared_ptr_to_me, result_var);
382   Target *target = exe_ctx.GetTargetPtr();
383   if (options.GetResultIsInternal() && result_var && target) {
384     target->GetPersistentExpressionStateForLanguage(m_language)
385         ->RemovePersistentVariable(result_var);
386   }
387   return expr_result;
388 }
389