1 //===-- LLVMUserExpression.cpp --------------------------------------------===//
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
10 #include "lldb/Expression/LLVMUserExpression.h"
11 #include "lldb/Core/Module.h"
12 #include "lldb/Core/ValueObjectConstResult.h"
13 #include "lldb/Expression/DiagnosticManager.h"
14 #include "lldb/Expression/ExpressionVariable.h"
15 #include "lldb/Expression/IRExecutionUnit.h"
16 #include "lldb/Expression/IRInterpreter.h"
17 #include "lldb/Expression/Materializer.h"
18 #include "lldb/Host/HostInfo.h"
19 #include "lldb/Symbol/Block.h"
20 #include "lldb/Symbol/Function.h"
21 #include "lldb/Symbol/ObjectFile.h"
22 #include "lldb/Symbol/SymbolVendor.h"
23 #include "lldb/Symbol/Type.h"
24 #include "lldb/Symbol/VariableList.h"
25 #include "lldb/Target/ABI.h"
26 #include "lldb/Target/ExecutionContext.h"
27 #include "lldb/Target/Process.h"
28 #include "lldb/Target/StackFrame.h"
29 #include "lldb/Target/Target.h"
30 #include "lldb/Target/ThreadPlan.h"
31 #include "lldb/Target/ThreadPlanCallUserExpression.h"
32 #include "lldb/Utility/ConstString.h"
33 #include "lldb/Utility/LLDBLog.h"
34 #include "lldb/Utility/Log.h"
35 #include "lldb/Utility/StreamString.h"
36
37 using namespace lldb;
38 using namespace lldb_private;
39
40 char LLVMUserExpression::ID;
41
LLVMUserExpression(ExecutionContextScope & exe_scope,llvm::StringRef expr,llvm::StringRef prefix,SourceLanguage language,ResultType desired_type,const EvaluateExpressionOptions & options)42 LLVMUserExpression::LLVMUserExpression(ExecutionContextScope &exe_scope,
43 llvm::StringRef expr,
44 llvm::StringRef prefix,
45 SourceLanguage language,
46 ResultType desired_type,
47 const EvaluateExpressionOptions &options)
48 : UserExpression(exe_scope, expr, prefix, language, desired_type, options),
49 m_stack_frame_bottom(LLDB_INVALID_ADDRESS),
50 m_stack_frame_top(LLDB_INVALID_ADDRESS), m_allow_cxx(false),
51 m_allow_objc(false), m_transformed_text(), m_execution_unit_sp(),
52 m_materializer_up(), m_jit_module_wp(), m_target(nullptr),
53 m_can_interpret(false), m_materialized_address(LLDB_INVALID_ADDRESS) {}
54
~LLVMUserExpression()55 LLVMUserExpression::~LLVMUserExpression() {
56 if (m_target) {
57 lldb::ModuleSP jit_module_sp(m_jit_module_wp.lock());
58 if (jit_module_sp)
59 m_target->GetImages().Remove(jit_module_sp);
60 }
61 }
62
63 lldb::ExpressionResults
DoExecute(DiagnosticManager & diagnostic_manager,ExecutionContext & exe_ctx,const EvaluateExpressionOptions & options,lldb::UserExpressionSP & shared_ptr_to_me,lldb::ExpressionVariableSP & result)64 LLVMUserExpression::DoExecute(DiagnosticManager &diagnostic_manager,
65 ExecutionContext &exe_ctx,
66 const EvaluateExpressionOptions &options,
67 lldb::UserExpressionSP &shared_ptr_to_me,
68 lldb::ExpressionVariableSP &result) {
69 // The expression log is quite verbose, and if you're just tracking the
70 // execution of the expression, it's quite convenient to have these logs come
71 // out with the STEP log as well.
72 Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step));
73
74 if (m_jit_start_addr == LLDB_INVALID_ADDRESS && !m_can_interpret) {
75 diagnostic_manager.PutString(
76 lldb::eSeverityError,
77 "Expression can't be run, because there is no JIT compiled function");
78 return lldb::eExpressionSetupError;
79 }
80
81 lldb::addr_t struct_address = LLDB_INVALID_ADDRESS;
82
83 if (!PrepareToExecuteJITExpression(diagnostic_manager, exe_ctx,
84 struct_address)) {
85 diagnostic_manager.Printf(
86 lldb::eSeverityError,
87 "errored out in %s, couldn't PrepareToExecuteJITExpression",
88 __FUNCTION__);
89 return lldb::eExpressionSetupError;
90 }
91
92 lldb::addr_t function_stack_bottom = LLDB_INVALID_ADDRESS;
93 lldb::addr_t function_stack_top = LLDB_INVALID_ADDRESS;
94
95 if (m_can_interpret) {
96 llvm::Module *module = m_execution_unit_sp->GetModule();
97 llvm::Function *function = m_execution_unit_sp->GetFunction();
98
99 if (!module || !function) {
100 diagnostic_manager.PutString(
101 lldb::eSeverityError, "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(lldb::eSeverityError,
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, *m_execution_unit_sp,
120 interpreter_error, function_stack_bottom,
121 function_stack_top, exe_ctx, options.GetTimeout());
122
123 if (!interpreter_error.Success()) {
124 diagnostic_manager.Printf(lldb::eSeverityError,
125 "supposed to interpret, but failed: %s",
126 interpreter_error.AsCString());
127 return lldb::eExpressionDiscarded;
128 }
129 } else {
130 if (!exe_ctx.HasThreadScope()) {
131 diagnostic_manager.Printf(lldb::eSeverityError,
132 "%s called with no thread selected",
133 __FUNCTION__);
134 return lldb::eExpressionSetupError;
135 }
136
137 // Store away the thread ID for error reporting, in case it exits
138 // during execution:
139 lldb::tid_t expr_thread_id = exe_ctx.GetThreadRef().GetID();
140
141 Address wrapper_address(m_jit_start_addr);
142
143 std::vector<lldb::addr_t> args;
144
145 if (!AddArguments(exe_ctx, args, struct_address, diagnostic_manager)) {
146 diagnostic_manager.Printf(lldb::eSeverityError,
147 "errored out in %s, couldn't AddArguments",
148 __FUNCTION__);
149 return lldb::eExpressionSetupError;
150 }
151
152 lldb::ThreadPlanSP call_plan_sp(new ThreadPlanCallUserExpression(
153 exe_ctx.GetThreadRef(), wrapper_address, args, options,
154 shared_ptr_to_me));
155
156 StreamString ss;
157 if (!call_plan_sp || !call_plan_sp->ValidatePlan(&ss)) {
158 diagnostic_manager.PutString(lldb::eSeverityError, ss.GetString());
159 return lldb::eExpressionSetupError;
160 }
161
162 ThreadPlanCallUserExpression *user_expression_plan =
163 static_cast<ThreadPlanCallUserExpression *>(call_plan_sp.get());
164
165 lldb::addr_t function_stack_pointer =
166 user_expression_plan->GetFunctionStackPointer();
167
168 function_stack_bottom = function_stack_pointer - HostInfo::GetPageSize();
169 function_stack_top = function_stack_pointer;
170
171 LLDB_LOGF(log,
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 LLDB_LOGF(log, "-- [UserExpression::Execute] Execution of expression "
185 "completed --");
186
187 if (execution_result == lldb::eExpressionInterrupted ||
188 execution_result == lldb::eExpressionHitBreakpoint) {
189 const char *error_desc = nullptr;
190
191 if (user_expression_plan) {
192 if (auto real_stop_info_sp = user_expression_plan->GetRealStopInfo())
193 error_desc = real_stop_info_sp->GetDescription();
194 }
195 if (error_desc)
196 diagnostic_manager.Printf(lldb::eSeverityError,
197 "Execution was interrupted, reason: %s.",
198 error_desc);
199 else
200 diagnostic_manager.PutString(lldb::eSeverityError,
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 lldb::eSeverityInfo,
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::eExpressionThreadVanished) {
230 diagnostic_manager.Printf(
231 lldb::eSeverityError,
232 "Couldn't complete execution; the thread "
233 "on which the expression was being run: 0x%" PRIx64
234 " exited during its execution.",
235 expr_thread_id);
236 return execution_result;
237 } else if (execution_result != lldb::eExpressionCompleted) {
238 diagnostic_manager.Printf(
239 lldb::eSeverityError, "Couldn't execute function; result was %s",
240 Process::ExecutionResultAsCString(execution_result));
241 return execution_result;
242 }
243 }
244
245 if (FinalizeJITExecution(diagnostic_manager, exe_ctx, result,
246 function_stack_bottom, function_stack_top)) {
247 return lldb::eExpressionCompleted;
248 } else {
249 return lldb::eExpressionResultUnavailable;
250 }
251 }
252
FinalizeJITExecution(DiagnosticManager & diagnostic_manager,ExecutionContext & exe_ctx,lldb::ExpressionVariableSP & result,lldb::addr_t function_stack_bottom,lldb::addr_t function_stack_top)253 bool LLVMUserExpression::FinalizeJITExecution(
254 DiagnosticManager &diagnostic_manager, ExecutionContext &exe_ctx,
255 lldb::ExpressionVariableSP &result, lldb::addr_t function_stack_bottom,
256 lldb::addr_t function_stack_top) {
257 Log *log = GetLog(LLDBLog::Expressions);
258
259 LLDB_LOGF(log, "-- [UserExpression::FinalizeJITExecution] Dematerializing "
260 "after execution --");
261
262 if (!m_dematerializer_sp) {
263 diagnostic_manager.Printf(lldb::eSeverityError,
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(lldb::eSeverityError,
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 lldb::eSeverityError,
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_up->GetStructByteSize(),
318 m_materializer_up->GetStructAlignment(),
319 lldb::ePermissionsReadable | lldb::ePermissionsWritable, policy,
320 zero_memory, alloc_error);
321
322 if (!alloc_error.Success()) {
323 diagnostic_manager.Printf(
324 lldb::eSeverityError,
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 size_t stack_frame_size = target->GetExprAllocSize();
337 if (stack_frame_size == 0) {
338 ABISP abi_sp;
339 if (process && (abi_sp = process->GetABI()))
340 stack_frame_size = abi_sp->GetStackFrameSize();
341 else
342 stack_frame_size = 512 * 1024;
343 }
344
345 const bool zero_memory = false;
346
347 m_stack_frame_bottom = m_execution_unit_sp->Malloc(
348 stack_frame_size, 8,
349 lldb::ePermissionsReadable | lldb::ePermissionsWritable,
350 IRMemoryMap::eAllocationPolicyHostOnly, zero_memory, alloc_error);
351
352 m_stack_frame_top = m_stack_frame_bottom + stack_frame_size;
353
354 if (!alloc_error.Success()) {
355 diagnostic_manager.Printf(
356 lldb::eSeverityError,
357 "Couldn't allocate space for the stack frame: %s",
358 alloc_error.AsCString());
359 return false;
360 }
361 }
362
363 Status materialize_error;
364
365 m_dematerializer_sp = m_materializer_up->Materialize(
366 frame, *m_execution_unit_sp, struct_address, materialize_error);
367
368 if (!materialize_error.Success()) {
369 diagnostic_manager.Printf(lldb::eSeverityError,
370 "Couldn't materialize: %s",
371 materialize_error.AsCString());
372 return false;
373 }
374 }
375 return true;
376 }
377
378