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#include "lldb/Expression/LLVMUserExpression.h"
10#include "lldb/Core/Module.h"
11#include "lldb/Expression/DiagnosticManager.h"
12#include "lldb/Expression/ExpressionVariable.h"
13#include "lldb/Expression/IRExecutionUnit.h"
14#include "lldb/Expression/IRInterpreter.h"
15#include "lldb/Expression/Materializer.h"
16#include "lldb/Host/HostInfo.h"
17#include "lldb/Symbol/Block.h"
18#include "lldb/Symbol/Function.h"
19#include "lldb/Symbol/ObjectFile.h"
20#include "lldb/Symbol/SymbolVendor.h"
21#include "lldb/Symbol/Type.h"
22#include "lldb/Symbol/VariableList.h"
23#include "lldb/Target/ABI.h"
24#include "lldb/Target/ExecutionContext.h"
25#include "lldb/Target/Process.h"
26#include "lldb/Target/StackFrame.h"
27#include "lldb/Target/Target.h"
28#include "lldb/Target/ThreadPlan.h"
29#include "lldb/Target/ThreadPlanCallUserExpression.h"
30#include "lldb/Utility/ConstString.h"
31#include "lldb/Utility/ErrorMessages.h"
32#include "lldb/Utility/LLDBLog.h"
33#include "lldb/Utility/Log.h"
34#include "lldb/Utility/StreamString.h"
35#include "lldb/ValueObject/ValueObjectConstResult.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 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
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: lldb::eSeverityError,
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: lldb::eSeverityError,
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: lldb::eSeverityError, str: "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(severity: lldb::eSeverityError,
111 format: "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&: *module, function&: *function, args, execution_unit&: *m_execution_unit_sp,
120 error&: interpreter_error, stack_frame_bottom: function_stack_bottom,
121 stack_frame_top: function_stack_top, exe_ctx, timeout: options.GetTimeout());
122
123 if (!interpreter_error.Success()) {
124 diagnostic_manager.Printf(severity: lldb::eSeverityError,
125 format: "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(severity: lldb::eSeverityError,
132 format: "%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(severity: lldb::eSeverityError,
147 format: "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(error: &ss)) {
158 diagnostic_manager.PutString(severity: lldb::eSeverityError, str: 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, thread_plan_sp&: 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 const char *explanation = execution_result == lldb::eExpressionInterrupted
191 ? "was interrupted"
192 : "hit a breakpoint";
193
194 if (user_expression_plan) {
195 if (auto real_stop_info_sp = user_expression_plan->GetRealStopInfo())
196 error_desc = real_stop_info_sp->GetDescription();
197 }
198
199 if (error_desc)
200 diagnostic_manager.Printf(severity: lldb::eSeverityError,
201 format: "Expression execution %s: %s.", explanation,
202 error_desc);
203 else
204 diagnostic_manager.Printf(severity: lldb::eSeverityError,
205 format: "Expression execution %s.", explanation);
206
207 if ((execution_result == lldb::eExpressionInterrupted &&
208 options.DoesUnwindOnError()) ||
209 (execution_result == lldb::eExpressionHitBreakpoint &&
210 options.DoesIgnoreBreakpoints()))
211 diagnostic_manager.AppendMessageToDiagnostic(
212 str: "The process has been returned to the state before expression "
213 "evaluation.");
214 else {
215 if (execution_result == lldb::eExpressionHitBreakpoint)
216 user_expression_plan->TransferExpressionOwnership();
217 diagnostic_manager.AppendMessageToDiagnostic(
218 str: "The process has been left at the point where it was "
219 "interrupted, use \"thread return -x\" to return to the state "
220 "before expression evaluation.");
221 }
222
223 return execution_result;
224 }
225
226 if (execution_result == lldb::eExpressionStoppedForDebug) {
227 diagnostic_manager.PutString(
228 severity: lldb::eSeverityInfo,
229 str: "Expression execution was halted at the first instruction of the "
230 "expression function because \"debug\" was requested.\n"
231 "Use \"thread return -x\" to return to the state before expression "
232 "evaluation.");
233 return execution_result;
234 }
235
236 if (execution_result == lldb::eExpressionThreadVanished) {
237 diagnostic_manager.Printf(severity: lldb::eSeverityError,
238 format: "Couldn't execute expression: the thread on "
239 "which the expression was being run (0x%" PRIx64
240 ") exited during its execution.",
241 expr_thread_id);
242 return execution_result;
243 }
244
245 if (execution_result != lldb::eExpressionCompleted) {
246 diagnostic_manager.Printf(severity: lldb::eSeverityError,
247 format: "Couldn't execute expression: result was %s",
248 toString(e: execution_result).c_str());
249 return execution_result;
250 }
251 }
252
253 if (FinalizeJITExecution(diagnostic_manager, exe_ctx, result,
254 function_stack_bottom, function_stack_top)) {
255 return lldb::eExpressionCompleted;
256 }
257
258 return lldb::eExpressionResultUnavailable;
259}
260
261bool LLVMUserExpression::FinalizeJITExecution(
262 DiagnosticManager &diagnostic_manager, ExecutionContext &exe_ctx,
263 lldb::ExpressionVariableSP &result, lldb::addr_t function_stack_bottom,
264 lldb::addr_t function_stack_top) {
265 Log *log = GetLog(mask: LLDBLog::Expressions);
266
267 LLDB_LOGF(log, "-- [UserExpression::FinalizeJITExecution] Dematerializing "
268 "after execution --");
269
270 if (!m_dematerializer_sp) {
271 diagnostic_manager.Printf(severity: lldb::eSeverityError,
272 format: "Couldn't apply expression side effects : no "
273 "dematerializer is present");
274 return false;
275 }
276
277 Status dematerialize_error;
278
279 m_dematerializer_sp->Dematerialize(err&: dematerialize_error, frame_top: function_stack_bottom,
280 frame_bottom: function_stack_top);
281
282 if (!dematerialize_error.Success()) {
283 diagnostic_manager.Printf(severity: lldb::eSeverityError,
284 format: "Couldn't apply expression side effects : %s",
285 dematerialize_error.AsCString(default_error_str: "unknown error"));
286 return false;
287 }
288
289 result =
290 GetResultAfterDematerialization(exe_scope: exe_ctx.GetBestExecutionContextScope());
291
292 if (result)
293 result->TransferAddress();
294
295 m_dematerializer_sp.reset();
296
297 return true;
298}
299
300bool LLVMUserExpression::PrepareToExecuteJITExpression(
301 DiagnosticManager &diagnostic_manager, ExecutionContext &exe_ctx,
302 lldb::addr_t &struct_address) {
303 lldb::TargetSP target;
304 lldb::ProcessSP process;
305 lldb::StackFrameSP frame;
306
307 if (!LockAndCheckContext(exe_ctx, target_sp&: target, process_sp&: process, frame_sp&: frame)) {
308 diagnostic_manager.PutString(
309 severity: lldb::eSeverityError,
310 str: "The context has changed before we could JIT the expression!");
311 return false;
312 }
313
314 if (m_jit_start_addr != LLDB_INVALID_ADDRESS || m_can_interpret) {
315 if (m_materialized_address == LLDB_INVALID_ADDRESS) {
316 Status alloc_error;
317
318 IRMemoryMap::AllocationPolicy policy =
319 m_can_interpret ? IRMemoryMap::eAllocationPolicyHostOnly
320 : IRMemoryMap::eAllocationPolicyMirror;
321
322 const bool zero_memory = false;
323
324 m_materialized_address = m_execution_unit_sp->Malloc(
325 size: m_materializer_up->GetStructByteSize(),
326 alignment: m_materializer_up->GetStructAlignment(),
327 permissions: lldb::ePermissionsReadable | lldb::ePermissionsWritable, policy,
328 zero_memory, error&: alloc_error);
329
330 if (!alloc_error.Success()) {
331 diagnostic_manager.Printf(
332 severity: lldb::eSeverityError,
333 format: "Couldn't allocate space for materialized struct: %s",
334 alloc_error.AsCString());
335 return false;
336 }
337 }
338
339 struct_address = m_materialized_address;
340
341 if (m_can_interpret && m_stack_frame_bottom == LLDB_INVALID_ADDRESS) {
342 Status alloc_error;
343
344 size_t stack_frame_size = target->GetExprAllocSize();
345 if (stack_frame_size == 0) {
346 ABISP abi_sp;
347 if (process && (abi_sp = process->GetABI()))
348 stack_frame_size = abi_sp->GetStackFrameSize();
349 else
350 stack_frame_size = 512 * 1024;
351 }
352
353 const bool zero_memory = false;
354
355 m_stack_frame_bottom = m_execution_unit_sp->Malloc(
356 size: stack_frame_size, alignment: 8,
357 permissions: lldb::ePermissionsReadable | lldb::ePermissionsWritable,
358 policy: IRMemoryMap::eAllocationPolicyHostOnly, zero_memory, error&: alloc_error);
359
360 m_stack_frame_top = m_stack_frame_bottom + stack_frame_size;
361
362 if (!alloc_error.Success()) {
363 diagnostic_manager.Printf(
364 severity: lldb::eSeverityError,
365 format: "Couldn't allocate space for the stack frame: %s",
366 alloc_error.AsCString());
367 return false;
368 }
369 }
370
371 Status materialize_error;
372
373 m_dematerializer_sp = m_materializer_up->Materialize(
374 frame_sp&: frame, map&: *m_execution_unit_sp, process_address: struct_address, err&: materialize_error);
375
376 if (!materialize_error.Success()) {
377 diagnostic_manager.Printf(severity: lldb::eSeverityError,
378 format: "Couldn't materialize: %s",
379 materialize_error.AsCString());
380 return false;
381 }
382 }
383 return true;
384}
385
386

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