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/Module.h"
21 #include "lldb/Core/StreamFile.h"
22 #include "lldb/Core/ValueObjectConstResult.h"
23 #include "lldb/Expression/DiagnosticManager.h"
24 #include "lldb/Expression/ExpressionSourceCode.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 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                                               Status &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, Status &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 looking up symbols, which will escape the
183   // context set by exe_ctx passed to Execute.
184   lldb::ThreadSP thread_sp = exe_ctx.GetThreadSP();
185   ThreadList::ExpressionExecutionThreadPusher execution_thread_pusher(
186       thread_sp);
187 
188   llvm::StringRef full_prefix;
189   llvm::StringRef option_prefix(options.GetPrefix());
190   std::string full_prefix_storage;
191   if (!prefix.empty() && !option_prefix.empty()) {
192     full_prefix_storage = prefix;
193     full_prefix_storage.append(option_prefix);
194     full_prefix = full_prefix_storage;
195   } else if (!prefix.empty())
196     full_prefix = prefix;
197   else
198     full_prefix = option_prefix;
199 
200   // If the language was not specified in the expression command, set it to the
201   // language in the target's properties if specified, else default to the
202   // langage for the frame.
203   if (language == lldb::eLanguageTypeUnknown) {
204     if (target->GetLanguage() != lldb::eLanguageTypeUnknown)
205       language = target->GetLanguage();
206     else if (StackFrame *frame = exe_ctx.GetFramePtr())
207       language = frame->GetLanguage();
208   }
209 
210   lldb::UserExpressionSP user_expression_sp(
211       target->GetUserExpressionForLanguage(expr, full_prefix, language,
212                                            desired_type, options, error));
213   if (error.Fail()) {
214     if (log)
215       log->Printf("== [UserExpression::Evaluate] Getting expression: %s ==",
216                   error.AsCString());
217     return lldb::eExpressionSetupError;
218   }
219 
220   if (log)
221     log->Printf("== [UserExpression::Evaluate] Parsing expression %s ==",
222                 expr.str().c_str());
223 
224   const bool keep_expression_in_memory = true;
225   const bool generate_debug_info = options.GetGenerateDebugInfo();
226 
227   if (options.InvokeCancelCallback(lldb::eExpressionEvaluationParse)) {
228     error.SetErrorString("expression interrupted by callback before parse");
229     result_valobj_sp = ValueObjectConstResult::Create(
230         exe_ctx.GetBestExecutionContextScope(), error);
231     return lldb::eExpressionInterrupted;
232   }
233 
234   DiagnosticManager diagnostic_manager;
235 
236   bool parse_success =
237       user_expression_sp->Parse(diagnostic_manager, exe_ctx, execution_policy,
238                                 keep_expression_in_memory, generate_debug_info);
239 
240   // Calculate the fixed expression always, since we need it for errors.
241   std::string tmp_fixed_expression;
242   if (fixed_expression == nullptr)
243     fixed_expression = &tmp_fixed_expression;
244 
245   const char *fixed_text = user_expression_sp->GetFixedText();
246   if (fixed_text != nullptr)
247     fixed_expression->append(fixed_text);
248 
249   // If there is a fixed expression, try to parse it:
250   if (!parse_success) {
251     execution_results = lldb::eExpressionParseError;
252     if (fixed_expression && !fixed_expression->empty() &&
253         options.GetAutoApplyFixIts()) {
254       lldb::UserExpressionSP fixed_expression_sp(
255           target->GetUserExpressionForLanguage(fixed_expression->c_str(),
256                                                full_prefix, language,
257                                                desired_type, options, error));
258       DiagnosticManager fixed_diagnostic_manager;
259       parse_success = fixed_expression_sp->Parse(
260           fixed_diagnostic_manager, exe_ctx, execution_policy,
261           keep_expression_in_memory, generate_debug_info);
262       if (parse_success) {
263         diagnostic_manager.Clear();
264         user_expression_sp = fixed_expression_sp;
265       } else {
266         // If the fixed expression failed to parse, don't tell the user about,
267         // that won't help.
268         fixed_expression->clear();
269       }
270     }
271 
272     if (!parse_success) {
273       if (!fixed_expression->empty() && target->GetEnableNotifyAboutFixIts()) {
274         error.SetExpressionErrorWithFormat(
275             execution_results,
276             "expression failed to parse, fixed expression suggested:\n  %s",
277             fixed_expression->c_str());
278       } else {
279         if (!diagnostic_manager.Diagnostics().size())
280           error.SetExpressionError(execution_results,
281                                    "expression failed to parse, unknown error");
282         else
283           error.SetExpressionError(execution_results,
284                                    diagnostic_manager.GetString().c_str());
285       }
286     }
287   }
288 
289   if (parse_success) {
290     // If a pointer to a lldb::ModuleSP was passed in, return the JIT'ed module
291     // if one was created
292     if (jit_module_sp_ptr)
293       *jit_module_sp_ptr = user_expression_sp->GetJITModule();
294 
295     lldb::ExpressionVariableSP expr_result;
296 
297     if (execution_policy == eExecutionPolicyNever &&
298         !user_expression_sp->CanInterpret()) {
299       if (log)
300         log->Printf("== [UserExpression::Evaluate] Expression may not run, but "
301                     "is not constant ==");
302 
303       if (!diagnostic_manager.Diagnostics().size())
304         error.SetExpressionError(lldb::eExpressionSetupError,
305                                  "expression needed to run but couldn't");
306     } else if (execution_policy == eExecutionPolicyTopLevel) {
307       error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric);
308       return lldb::eExpressionCompleted;
309     } else {
310       if (options.InvokeCancelCallback(lldb::eExpressionEvaluationExecution)) {
311         error.SetExpressionError(
312             lldb::eExpressionInterrupted,
313             "expression interrupted by callback before execution");
314         result_valobj_sp = ValueObjectConstResult::Create(
315             exe_ctx.GetBestExecutionContextScope(), error);
316         return lldb::eExpressionInterrupted;
317       }
318 
319       diagnostic_manager.Clear();
320 
321       if (log)
322         log->Printf("== [UserExpression::Evaluate] Executing expression ==");
323 
324       execution_results =
325           user_expression_sp->Execute(diagnostic_manager, exe_ctx, options,
326                                       user_expression_sp, expr_result);
327 
328       if (execution_results != lldb::eExpressionCompleted) {
329         if (log)
330           log->Printf("== [UserExpression::Evaluate] Execution completed "
331                       "abnormally ==");
332 
333         if (!diagnostic_manager.Diagnostics().size())
334           error.SetExpressionError(
335               execution_results, "expression failed to execute, unknown error");
336         else
337           error.SetExpressionError(execution_results,
338                                    diagnostic_manager.GetString().c_str());
339       } else {
340         if (expr_result) {
341           result_valobj_sp = expr_result->GetValueObject();
342 
343           if (log)
344             log->Printf("== [UserExpression::Evaluate] Execution completed "
345                         "normally with result %s ==",
346                         result_valobj_sp->GetValueAsCString());
347         } else {
348           if (log)
349             log->Printf("== [UserExpression::Evaluate] Execution completed "
350                         "normally with no result ==");
351 
352           error.SetError(UserExpression::kNoResult, lldb::eErrorTypeGeneric);
353         }
354       }
355     }
356   }
357 
358   if (options.InvokeCancelCallback(lldb::eExpressionEvaluationComplete)) {
359     error.SetExpressionError(
360         lldb::eExpressionInterrupted,
361         "expression interrupted by callback after complete");
362     return lldb::eExpressionInterrupted;
363   }
364 
365   if (result_valobj_sp.get() == NULL) {
366     result_valobj_sp = ValueObjectConstResult::Create(
367         exe_ctx.GetBestExecutionContextScope(), error);
368   }
369 
370   return execution_results;
371 }
372 
373 lldb::ExpressionResults
374 UserExpression::Execute(DiagnosticManager &diagnostic_manager,
375                         ExecutionContext &exe_ctx,
376                         const EvaluateExpressionOptions &options,
377                         lldb::UserExpressionSP &shared_ptr_to_me,
378                         lldb::ExpressionVariableSP &result_var) {
379   lldb::ExpressionResults expr_result = DoExecute(
380       diagnostic_manager, exe_ctx, options, shared_ptr_to_me, result_var);
381   Target *target = exe_ctx.GetTargetPtr();
382   if (options.GetResultIsInternal() && result_var && target) {
383     target->GetPersistentExpressionStateForLanguage(m_language)
384         ->RemovePersistentVariable(result_var);
385   }
386   return expr_result;
387 }
388