lldb/source/Expression/LLVMUserExpression.cpp

   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
  37 using namespace lldb;
  38 using namespace lldb_private;
  39
  40 char LLVMUserExpression::ID;
  41
  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
  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
  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(lldb::eSeverityError,
 239                                 "Couldn't execute function; result was %s",
 240                                 toString(execution_result).c_str());
 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
 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
 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