1 //===-- LLVMUserExpression.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 // C Includes
11 // C++ Includes
12 
13 // Project includes
14 #include "lldb/Expression/LLVMUserExpression.h"
15 #include "lldb/Core/ConstString.h"
16 #include "lldb/Core/Log.h"
17 #include "lldb/Core/Module.h"
18 #include "lldb/Core/StreamFile.h"
19 #include "lldb/Core/StreamString.h"
20 #include "lldb/Core/ValueObjectConstResult.h"
21 #include "lldb/Expression/DiagnosticManager.h"
22 #include "lldb/Expression/ExpressionSourceCode.h"
23 #include "lldb/Expression/IRExecutionUnit.h"
24 #include "lldb/Expression/IRInterpreter.h"
25 #include "lldb/Expression/Materializer.h"
26 #include "lldb/Host/HostInfo.h"
27 #include "lldb/Symbol/Block.h"
28 #include "lldb/Symbol/ClangASTContext.h"
29 #include "lldb/Symbol/ClangExternalASTSourceCommon.h"
30 #include "lldb/Symbol/Function.h"
31 #include "lldb/Symbol/ObjectFile.h"
32 #include "lldb/Symbol/SymbolVendor.h"
33 #include "lldb/Symbol/Type.h"
34 #include "lldb/Symbol/VariableList.h"
35 #include "lldb/Target/ExecutionContext.h"
36 #include "lldb/Target/Process.h"
37 #include "lldb/Target/StackFrame.h"
38 #include "lldb/Target/Target.h"
39 #include "lldb/Target/ThreadPlan.h"
40 #include "lldb/Target/ThreadPlanCallUserExpression.h"
41 
42 using namespace lldb_private;
43 
44 LLVMUserExpression::LLVMUserExpression(ExecutionContextScope &exe_scope,
45                                        const char *expr,
46                                        const char *expr_prefix,
47                                        lldb::LanguageType language,
48                                        ResultType desired_type,
49                                        const EvaluateExpressionOptions &options)
50     : UserExpression(exe_scope, expr, expr_prefix, language, desired_type,
51                      options),
52       m_stack_frame_bottom(LLDB_INVALID_ADDRESS),
53       m_stack_frame_top(LLDB_INVALID_ADDRESS), m_transformed_text(),
54       m_execution_unit_sp(), m_materializer_ap(), m_jit_module_wp(),
55       m_enforce_valid_object(true), m_in_cplusplus_method(false),
56       m_in_objectivec_method(false), m_in_static_method(false),
57       m_needs_object_ptr(false), m_target(NULL), m_can_interpret(false),
58       m_materialized_address(LLDB_INVALID_ADDRESS) {}
59 
60 LLVMUserExpression::~LLVMUserExpression() {
61   if (m_target) {
62     lldb::ModuleSP jit_module_sp(m_jit_module_wp.lock());
63     if (jit_module_sp)
64       m_target->GetImages().Remove(jit_module_sp);
65   }
66 }
67 
68 lldb::ExpressionResults
69 LLVMUserExpression::DoExecute(DiagnosticManager &diagnostic_manager,
70                               ExecutionContext &exe_ctx,
71                               const EvaluateExpressionOptions &options,
72                               lldb::UserExpressionSP &shared_ptr_to_me,
73                               lldb::ExpressionVariableSP &result) {
74   // The expression log is quite verbose, and if you're just tracking the
75   // execution of the
76   // expression, it's quite convenient to have these logs come out with the STEP
77   // log as well.
78   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_EXPRESSIONS |
79                                                   LIBLLDB_LOG_STEP));
80 
81   if (m_jit_start_addr != LLDB_INVALID_ADDRESS || m_can_interpret) {
82     lldb::addr_t struct_address = LLDB_INVALID_ADDRESS;
83 
84     if (!PrepareToExecuteJITExpression(diagnostic_manager, exe_ctx,
85                                        struct_address)) {
86       diagnostic_manager.Printf(
87           eDiagnosticSeverityError,
88           "errored out in %s, couldn't PrepareToExecuteJITExpression",
89           __FUNCTION__);
90       return lldb::eExpressionSetupError;
91     }
92 
93     lldb::addr_t function_stack_bottom = LLDB_INVALID_ADDRESS;
94     lldb::addr_t function_stack_top = LLDB_INVALID_ADDRESS;
95 
96     if (m_can_interpret) {
97       llvm::Module *module = m_execution_unit_sp->GetModule();
98       llvm::Function *function = m_execution_unit_sp->GetFunction();
99 
100       if (!module || !function) {
101         diagnostic_manager.PutCString(
102             eDiagnosticSeverityError,
103             "supposed to interpret, but nothing is there");
104         return lldb::eExpressionSetupError;
105       }
106 
107       Error interpreter_error;
108 
109       std::vector<lldb::addr_t> args;
110 
111       if (!AddArguments(exe_ctx, args, struct_address, diagnostic_manager)) {
112         diagnostic_manager.Printf(eDiagnosticSeverityError,
113                                   "errored out in %s, couldn't AddArguments",
114                                   __FUNCTION__);
115         return lldb::eExpressionSetupError;
116       }
117 
118       function_stack_bottom = m_stack_frame_bottom;
119       function_stack_top = m_stack_frame_top;
120 
121       IRInterpreter::Interpret(*module, *function, args,
122                                *m_execution_unit_sp.get(), interpreter_error,
123                                function_stack_bottom, function_stack_top,
124                                exe_ctx);
125 
126       if (!interpreter_error.Success()) {
127         diagnostic_manager.Printf(eDiagnosticSeverityError,
128                                   "supposed to interpret, but failed: %s",
129                                   interpreter_error.AsCString());
130         return lldb::eExpressionDiscarded;
131       }
132     } else {
133       if (!exe_ctx.HasThreadScope()) {
134         diagnostic_manager.Printf(eDiagnosticSeverityError,
135                                   "%s called with no thread selected",
136                                   __FUNCTION__);
137         return lldb::eExpressionSetupError;
138       }
139 
140       Address wrapper_address(m_jit_start_addr);
141 
142       std::vector<lldb::addr_t> args;
143 
144       if (!AddArguments(exe_ctx, args, struct_address, diagnostic_manager)) {
145         diagnostic_manager.Printf(eDiagnosticSeverityError,
146                                   "errored out in %s, couldn't AddArguments",
147                                   __FUNCTION__);
148         return lldb::eExpressionSetupError;
149       }
150 
151       lldb::ThreadPlanSP call_plan_sp(new ThreadPlanCallUserExpression(
152           exe_ctx.GetThreadRef(), wrapper_address, args, options,
153           shared_ptr_to_me));
154 
155       StreamString ss;
156       if (!call_plan_sp || !call_plan_sp->ValidatePlan(&ss)) {
157         diagnostic_manager.PutCString(eDiagnosticSeverityError, ss.GetData());
158         return lldb::eExpressionSetupError;
159       }
160 
161       ThreadPlanCallUserExpression *user_expression_plan =
162           static_cast<ThreadPlanCallUserExpression *>(call_plan_sp.get());
163 
164       lldb::addr_t function_stack_pointer =
165           user_expression_plan->GetFunctionStackPointer();
166 
167       function_stack_bottom = function_stack_pointer - HostInfo::GetPageSize();
168       function_stack_top = function_stack_pointer;
169 
170       if (log)
171         log->Printf(
172             "-- [UserExpression::Execute] Execution of expression begins --");
173 
174       if (exe_ctx.GetProcessPtr())
175         exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
176 
177       lldb::ExpressionResults execution_result =
178           exe_ctx.GetProcessRef().RunThreadPlan(exe_ctx, call_plan_sp, options,
179                                                 diagnostic_manager);
180 
181       if (exe_ctx.GetProcessPtr())
182         exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
183 
184       if (log)
185         log->Printf("-- [UserExpression::Execute] Execution of expression "
186                     "completed --");
187 
188       if (execution_result == lldb::eExpressionInterrupted ||
189           execution_result == lldb::eExpressionHitBreakpoint) {
190         const char *error_desc = NULL;
191 
192         if (call_plan_sp) {
193           lldb::StopInfoSP real_stop_info_sp = call_plan_sp->GetRealStopInfo();
194           if (real_stop_info_sp)
195             error_desc = real_stop_info_sp->GetDescription();
196         }
197         if (error_desc)
198           diagnostic_manager.Printf(eDiagnosticSeverityError,
199                                     "Execution was interrupted, reason: %s.",
200                                     error_desc);
201         else
202           diagnostic_manager.PutCString(eDiagnosticSeverityError,
203                                         "Execution was interrupted.");
204 
205         if ((execution_result == lldb::eExpressionInterrupted &&
206              options.DoesUnwindOnError()) ||
207             (execution_result == lldb::eExpressionHitBreakpoint &&
208              options.DoesIgnoreBreakpoints()))
209           diagnostic_manager.AppendMessageToDiagnostic(
210               "The process has been returned to the state before expression "
211               "evaluation.");
212         else {
213           if (execution_result == lldb::eExpressionHitBreakpoint)
214             user_expression_plan->TransferExpressionOwnership();
215           diagnostic_manager.AppendMessageToDiagnostic(
216               "The process has been left at the point where it was "
217               "interrupted, "
218               "use \"thread return -x\" to return to the state before "
219               "expression evaluation.");
220         }
221 
222         return execution_result;
223       } else if (execution_result == lldb::eExpressionStoppedForDebug) {
224         diagnostic_manager.PutCString(
225             eDiagnosticSeverityRemark,
226             "Execution was halted at the first instruction of the expression "
227             "function because \"debug\" was requested.\n"
228             "Use \"thread return -x\" to return to the state before expression "
229             "evaluation.");
230         return execution_result;
231       } else if (execution_result != lldb::eExpressionCompleted) {
232         diagnostic_manager.Printf(
233             eDiagnosticSeverityError,
234             "Couldn't execute function; result was %s",
235             Process::ExecutionResultAsCString(execution_result));
236         return execution_result;
237       }
238     }
239 
240     if (FinalizeJITExecution(diagnostic_manager, exe_ctx, result,
241                              function_stack_bottom, function_stack_top)) {
242       return lldb::eExpressionCompleted;
243     } else {
244       return lldb::eExpressionResultUnavailable;
245     }
246   } else {
247     diagnostic_manager.PutCString(
248         eDiagnosticSeverityError,
249         "Expression can't be run, because there is no JIT compiled function");
250     return lldb::eExpressionSetupError;
251   }
252 }
253 
254 bool LLVMUserExpression::FinalizeJITExecution(
255     DiagnosticManager &diagnostic_manager, ExecutionContext &exe_ctx,
256     lldb::ExpressionVariableSP &result, lldb::addr_t function_stack_bottom,
257     lldb::addr_t function_stack_top) {
258   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
259 
260   if (log)
261     log->Printf("-- [UserExpression::FinalizeJITExecution] Dematerializing "
262                 "after execution --");
263 
264   if (!m_dematerializer_sp) {
265     diagnostic_manager.Printf(eDiagnosticSeverityError,
266                               "Couldn't apply expression side effects : no "
267                               "dematerializer is present");
268     return false;
269   }
270 
271   Error dematerialize_error;
272 
273   m_dematerializer_sp->Dematerialize(dematerialize_error, function_stack_bottom,
274                                      function_stack_top);
275 
276   if (!dematerialize_error.Success()) {
277     diagnostic_manager.Printf(eDiagnosticSeverityError,
278                               "Couldn't apply expression side effects : %s",
279                               dematerialize_error.AsCString("unknown error"));
280     return false;
281   }
282 
283   result =
284       GetResultAfterDematerialization(exe_ctx.GetBestExecutionContextScope());
285 
286   if (result)
287     result->TransferAddress();
288 
289   m_dematerializer_sp.reset();
290 
291   return true;
292 }
293 
294 bool LLVMUserExpression::PrepareToExecuteJITExpression(
295     DiagnosticManager &diagnostic_manager, ExecutionContext &exe_ctx,
296     lldb::addr_t &struct_address) {
297   lldb::TargetSP target;
298   lldb::ProcessSP process;
299   lldb::StackFrameSP frame;
300 
301   if (!LockAndCheckContext(exe_ctx, target, process, frame)) {
302     diagnostic_manager.PutCString(
303         eDiagnosticSeverityError,
304         "The context has changed before we could JIT the expression!");
305     return false;
306   }
307 
308   if (m_jit_start_addr != LLDB_INVALID_ADDRESS || m_can_interpret) {
309     if (m_materialized_address == LLDB_INVALID_ADDRESS) {
310       Error alloc_error;
311 
312       IRMemoryMap::AllocationPolicy policy =
313           m_can_interpret ? IRMemoryMap::eAllocationPolicyHostOnly
314                           : IRMemoryMap::eAllocationPolicyMirror;
315 
316       const bool zero_memory = false;
317 
318       m_materialized_address = m_execution_unit_sp->Malloc(
319           m_materializer_ap->GetStructByteSize(),
320           m_materializer_ap->GetStructAlignment(),
321           lldb::ePermissionsReadable | lldb::ePermissionsWritable, policy,
322           zero_memory, alloc_error);
323 
324       if (!alloc_error.Success()) {
325         diagnostic_manager.Printf(
326             eDiagnosticSeverityError,
327             "Couldn't allocate space for materialized struct: %s",
328             alloc_error.AsCString());
329         return false;
330       }
331     }
332 
333     struct_address = m_materialized_address;
334 
335     if (m_can_interpret && m_stack_frame_bottom == LLDB_INVALID_ADDRESS) {
336       Error alloc_error;
337 
338       const size_t stack_frame_size = 512 * 1024;
339 
340       const bool zero_memory = false;
341 
342       m_stack_frame_bottom = m_execution_unit_sp->Malloc(
343           stack_frame_size, 8,
344           lldb::ePermissionsReadable | lldb::ePermissionsWritable,
345           IRMemoryMap::eAllocationPolicyHostOnly, zero_memory, alloc_error);
346 
347       m_stack_frame_top = m_stack_frame_bottom + stack_frame_size;
348 
349       if (!alloc_error.Success()) {
350         diagnostic_manager.Printf(
351             eDiagnosticSeverityError,
352             "Couldn't allocate space for the stack frame: %s",
353             alloc_error.AsCString());
354         return false;
355       }
356     }
357 
358     Error materialize_error;
359 
360     m_dematerializer_sp = m_materializer_ap->Materialize(
361         frame, *m_execution_unit_sp, struct_address, materialize_error);
362 
363     if (!materialize_error.Success()) {
364       diagnostic_manager.Printf(eDiagnosticSeverityError,
365                                 "Couldn't materialize: %s",
366                                 materialize_error.AsCString());
367       return false;
368     }
369   }
370   return true;
371 }
372 
373 lldb::ModuleSP LLVMUserExpression::GetJITModule() {
374   if (m_execution_unit_sp)
375     return m_execution_unit_sp->GetJITModule();
376   return lldb::ModuleSP();
377 }
378