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