UserExpression.cpp revision 360784 
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
47using namespace lldb_private;
48
49char UserExpression::ID;
50
51UserExpression::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
59UserExpression::~UserExpression() {}
60
61void 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
70bool 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
95bool 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
103lldb::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
141lldb::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
389lldb::ExpressionResults
390UserExpression::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