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
37using namespace lldb;
38using namespace lldb_private;
39
40char LLVMUserExpression::ID;
41
42LLVMUserExpression::LLVMUserExpression(ExecutionContextScope &exe_scope,
43 llvm::StringRef expr,
44 llvm::StringRef prefix,
45 lldb::LanguageType 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
55LLVMUserExpression::~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(module_sp: jit_module_sp);
60 }
61}
62
63lldb::ExpressionResults
64LLVMUserExpression::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(mask: LLDBLog::Expressions | LLDBLog::Step));
73
74 if (m_jit_start_addr == LLDB_INVALID_ADDRESS && !m_can_interpret) {
75 diagnostic_manager.PutString(
76 severity: eDiagnosticSeverityError,
77 str: "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 severity: eDiagnosticSeverityError,
87 format: "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 severity: eDiagnosticSeverityError,
102 str: "supposed to interpret, but nothing is there");
103 return lldb::eExpressionSetupError;
104 }
105
106 Status interpreter_error;
107
108 std::vector<lldb::addr_t> args;
109
110 if (!AddArguments(exe_ctx, args, struct_address, diagnostic_manager)) {
111 diagnostic_manager.Printf(severity: eDiagnosticSeverityError,
112 format: "errored out in %s, couldn't AddArguments",
113 __FUNCTION__);
114 return lldb::eExpressionSetupError;
115 }
116
117 function_stack_bottom = m_stack_frame_bottom;
118 function_stack_top = m_stack_frame_top;
119
120 IRInterpreter::Interpret(module&: *module, function&: *function, args, execution_unit&: *m_execution_unit_sp,
121 error&: interpreter_error, stack_frame_bottom: function_stack_bottom,
122 stack_frame_top: function_stack_top, exe_ctx, timeout: options.GetTimeout());
123
124 if (!interpreter_error.Success()) {
125 diagnostic_manager.Printf(severity: eDiagnosticSeverityError,
126 format: "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(severity: eDiagnosticSeverityError,
133 format: "%s called with no thread selected",
134 __FUNCTION__);
135 return lldb::eExpressionSetupError;
136 }
137
138 // Store away the thread ID for error reporting, in case it exits
139 // during execution:
140 lldb::tid_t expr_thread_id = exe_ctx.GetThreadRef().GetID();
141
142 Address wrapper_address(m_jit_start_addr);
143
144 std::vector<lldb::addr_t> args;
145
146 if (!AddArguments(exe_ctx, args, struct_address, diagnostic_manager)) {
147 diagnostic_manager.Printf(severity: eDiagnosticSeverityError,
148 format: "errored out in %s, couldn't AddArguments",
149 __FUNCTION__);
150 return lldb::eExpressionSetupError;
151 }
152
153 lldb::ThreadPlanSP call_plan_sp(new ThreadPlanCallUserExpression(
154 exe_ctx.GetThreadRef(), wrapper_address, args, options,
155 shared_ptr_to_me));
156
157 StreamString ss;
158 if (!call_plan_sp || !call_plan_sp->ValidatePlan(error: &ss)) {
159 diagnostic_manager.PutString(severity: eDiagnosticSeverityError, str: ss.GetString());
160 return lldb::eExpressionSetupError;
161 }
162
163 ThreadPlanCallUserExpression *user_expression_plan =
164 static_cast<ThreadPlanCallUserExpression *>(call_plan_sp.get());
165
166 lldb::addr_t function_stack_pointer =
167 user_expression_plan->GetFunctionStackPointer();
168
169 function_stack_bottom = function_stack_pointer - HostInfo::GetPageSize();
170 function_stack_top = function_stack_pointer;
171
172 LLDB_LOGF(log,
173 "-- [UserExpression::Execute] Execution of expression begins --");
174
175 if (exe_ctx.GetProcessPtr())
176 exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
177
178 lldb::ExpressionResults execution_result =
179 exe_ctx.GetProcessRef().RunThreadPlan(exe_ctx, thread_plan_sp&: call_plan_sp, options,
180 diagnostic_manager);
181
182 if (exe_ctx.GetProcessPtr())
183 exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
184
185 LLDB_LOGF(log, "-- [UserExpression::Execute] Execution of expression "
186 "completed --");
187
188 if (execution_result == lldb::eExpressionInterrupted ||
189 execution_result == lldb::eExpressionHitBreakpoint) {
190 const char *error_desc = nullptr;
191
192 if (user_expression_plan) {
193 if (auto real_stop_info_sp = user_expression_plan->GetRealStopInfo())
194 error_desc = real_stop_info_sp->GetDescription();
195 }
196 if (error_desc)
197 diagnostic_manager.Printf(severity: eDiagnosticSeverityError,
198 format: "Execution was interrupted, reason: %s.",
199 error_desc);
200 else
201 diagnostic_manager.PutString(severity: eDiagnosticSeverityError,
202 str: "Execution was interrupted.");
203
204 if ((execution_result == lldb::eExpressionInterrupted &&
205 options.DoesUnwindOnError()) ||
206 (execution_result == lldb::eExpressionHitBreakpoint &&
207 options.DoesIgnoreBreakpoints()))
208 diagnostic_manager.AppendMessageToDiagnostic(
209 str: "The process has been returned to the state before expression "
210 "evaluation.");
211 else {
212 if (execution_result == lldb::eExpressionHitBreakpoint)
213 user_expression_plan->TransferExpressionOwnership();
214 diagnostic_manager.AppendMessageToDiagnostic(
215 str: "The process has been left at the point where it was "
216 "interrupted, "
217 "use \"thread return -x\" to return to the state before "
218 "expression evaluation.");
219 }
220
221 return execution_result;
222 } else if (execution_result == lldb::eExpressionStoppedForDebug) {
223 diagnostic_manager.PutString(
224 severity: eDiagnosticSeverityRemark,
225 str: "Execution was halted at the first instruction of the expression "
226 "function because \"debug\" was requested.\n"
227 "Use \"thread return -x\" to return to the state before expression "
228 "evaluation.");
229 return execution_result;
230 } else if (execution_result == lldb::eExpressionThreadVanished) {
231 diagnostic_manager.Printf(
232 severity: eDiagnosticSeverityError,
233 format: "Couldn't complete execution; the thread "
234 "on which the expression was being run: 0x%" PRIx64
235 " exited during its execution.",
236 expr_thread_id);
237 return execution_result;
238 } else if (execution_result != lldb::eExpressionCompleted) {
239 diagnostic_manager.Printf(
240 severity: eDiagnosticSeverityError, format: "Couldn't execute function; result was %s",
241 Process::ExecutionResultAsCString(result: execution_result));
242 return execution_result;
243 }
244 }
245
246 if (FinalizeJITExecution(diagnostic_manager, exe_ctx, result,
247 function_stack_bottom, function_stack_top)) {
248 return lldb::eExpressionCompleted;
249 } else {
250 return lldb::eExpressionResultUnavailable;
251 }
252}
253
254bool 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 = GetLog(mask: LLDBLog::Expressions);
259
260 LLDB_LOGF(log, "-- [UserExpression::FinalizeJITExecution] Dematerializing "
261 "after execution --");
262
263 if (!m_dematerializer_sp) {
264 diagnostic_manager.Printf(severity: eDiagnosticSeverityError,
265 format: "Couldn't apply expression side effects : no "
266 "dematerializer is present");
267 return false;
268 }
269
270 Status dematerialize_error;
271
272 m_dematerializer_sp->Dematerialize(err&: dematerialize_error, frame_top: function_stack_bottom,
273 frame_bottom: function_stack_top);
274
275 if (!dematerialize_error.Success()) {
276 diagnostic_manager.Printf(severity: eDiagnosticSeverityError,
277 format: "Couldn't apply expression side effects : %s",
278 dematerialize_error.AsCString(default_error_str: "unknown error"));
279 return false;
280 }
281
282 result =
283 GetResultAfterDematerialization(exe_scope: exe_ctx.GetBestExecutionContextScope());
284
285 if (result)
286 result->TransferAddress();
287
288 m_dematerializer_sp.reset();
289
290 return true;
291}
292
293bool LLVMUserExpression::PrepareToExecuteJITExpression(
294 DiagnosticManager &diagnostic_manager, ExecutionContext &exe_ctx,
295 lldb::addr_t &struct_address) {
296 lldb::TargetSP target;
297 lldb::ProcessSP process;
298 lldb::StackFrameSP frame;
299
300 if (!LockAndCheckContext(exe_ctx, target_sp&: target, process_sp&: process, frame_sp&: frame)) {
301 diagnostic_manager.PutString(
302 severity: eDiagnosticSeverityError,
303 str: "The context has changed before we could JIT the expression!");
304 return false;
305 }
306
307 if (m_jit_start_addr != LLDB_INVALID_ADDRESS || m_can_interpret) {
308 if (m_materialized_address == LLDB_INVALID_ADDRESS) {
309 Status alloc_error;
310
311 IRMemoryMap::AllocationPolicy policy =
312 m_can_interpret ? IRMemoryMap::eAllocationPolicyHostOnly
313 : IRMemoryMap::eAllocationPolicyMirror;
314
315 const bool zero_memory = false;
316
317 m_materialized_address = m_execution_unit_sp->Malloc(
318 size: m_materializer_up->GetStructByteSize(),
319 alignment: m_materializer_up->GetStructAlignment(),
320 permissions: lldb::ePermissionsReadable | lldb::ePermissionsWritable, policy,
321 zero_memory, error&: alloc_error);
322
323 if (!alloc_error.Success()) {
324 diagnostic_manager.Printf(
325 severity: eDiagnosticSeverityError,
326 format: "Couldn't allocate space for materialized struct: %s",
327 alloc_error.AsCString());
328 return false;
329 }
330 }
331
332 struct_address = m_materialized_address;
333
334 if (m_can_interpret && m_stack_frame_bottom == LLDB_INVALID_ADDRESS) {
335 Status alloc_error;
336
337 size_t stack_frame_size = target->GetExprAllocSize();
338 if (stack_frame_size == 0) {
339 ABISP abi_sp;
340 if (process && (abi_sp = process->GetABI()))
341 stack_frame_size = abi_sp->GetStackFrameSize();
342 else
343 stack_frame_size = 512 * 1024;
344 }
345
346 const bool zero_memory = false;
347
348 m_stack_frame_bottom = m_execution_unit_sp->Malloc(
349 size: stack_frame_size, alignment: 8,
350 permissions: lldb::ePermissionsReadable | lldb::ePermissionsWritable,
351 policy: IRMemoryMap::eAllocationPolicyHostOnly, zero_memory, error&: alloc_error);
352
353 m_stack_frame_top = m_stack_frame_bottom + stack_frame_size;
354
355 if (!alloc_error.Success()) {
356 diagnostic_manager.Printf(
357 severity: eDiagnosticSeverityError,
358 format: "Couldn't allocate space for the stack frame: %s",
359 alloc_error.AsCString());
360 return false;
361 }
362 }
363
364 Status materialize_error;
365
366 m_dematerializer_sp = m_materializer_up->Materialize(
367 frame_sp&: frame, map&: *m_execution_unit_sp, process_address: struct_address, err&: materialize_error);
368
369 if (!materialize_error.Success()) {
370 diagnostic_manager.Printf(severity: eDiagnosticSeverityError,
371 format: "Couldn't materialize: %s",
372 materialize_error.AsCString());
373 return false;
374 }
375 }
376 return true;
377}
378
379

source code of lldb/source/Expression/LLVMUserExpression.cpp