lldb/source/Expression/FunctionCaller.cpp

   1 //===-- FunctionCaller.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/FunctionCaller.h"
  10 #include "lldb/Core/Module.h"
  11 #include "lldb/Core/Progress.h"
  12 #include "lldb/Expression/DiagnosticManager.h"
  13 #include "lldb/Expression/IRExecutionUnit.h"
  14 #include "lldb/Interpreter/CommandReturnObject.h"
  15 #include "lldb/Symbol/Function.h"
  16 #include "lldb/Symbol/Type.h"
  17 #include "lldb/Target/ExecutionContext.h"
  18 #include "lldb/Target/Process.h"
  19 #include "lldb/Target/RegisterContext.h"
  20 #include "lldb/Target/Target.h"
  21 #include "lldb/Target/Thread.h"
  22 #include "lldb/Target/ThreadPlan.h"
  23 #include "lldb/Target/ThreadPlanCallFunction.h"
  24 #include "lldb/Utility/DataExtractor.h"
  25 #include "lldb/Utility/ErrorMessages.h"
  26 #include "lldb/Utility/LLDBLog.h"
  27 #include "lldb/Utility/Log.h"
  28 #include "lldb/Utility/State.h"
  29 #include "lldb/ValueObject/ValueObject.h"
  30 #include "lldb/ValueObject/ValueObjectList.h"
  31
  32 using namespace lldb_private;
  33
  34 char FunctionCaller::ID;
  35
  36 // FunctionCaller constructor
  37 FunctionCaller::FunctionCaller(ExecutionContextScope &exe_scope,
  38                                const CompilerType &return_type,
  39                                const Address &functionAddress,
  40                                const ValueList &arg_value_list,
  41                                const char *name)
  42     : Expression(exe_scope), m_execution_unit_sp(), m_parser(),
  43       m_jit_module_wp(), m_name(name ? name : "<unknown>"),
  44       m_function_ptr(nullptr), m_function_addr(functionAddress),
  45       m_function_return_type(return_type),
  46       m_wrapper_function_name("__lldb_caller_function"),
  47       m_wrapper_struct_name("__lldb_caller_struct"), m_wrapper_args_addrs(),
  48       m_struct_valid(false), m_struct_size(0), m_return_size(0),
  49       m_return_offset(0), m_arg_values(arg_value_list), m_compiled(false),
  50       m_JITted(false) {
  51   m_jit_process_wp = lldb::ProcessWP(exe_scope.CalculateProcess());
  52   // Can't make a FunctionCaller without a process.
  53   assert(m_jit_process_wp.lock());
  54 }
  55
  56 // Destructor
  57 FunctionCaller::~FunctionCaller() {
  58   lldb::ProcessSP process_sp(m_jit_process_wp.lock());
  59   if (process_sp) {
  60     lldb::ModuleSP jit_module_sp(m_jit_module_wp.lock());
  61     if (jit_module_sp)
  62       process_sp->GetTarget().GetImages().Remove(jit_module_sp);
  63   }
  64 }
  65
  66 bool FunctionCaller::WriteFunctionWrapper(
  67     ExecutionContext &exe_ctx, DiagnosticManager &diagnostic_manager) {
  68   Process *process = exe_ctx.GetProcessPtr();
  69
  70   if (!process) {
  71     diagnostic_manager.Printf(lldb::eSeverityError, "no process.");
  72     return false;
  73   }
  74
  75   lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
  76
  77   if (process != jit_process_sp.get()) {
  78     diagnostic_manager.Printf(lldb::eSeverityError,
  79                               "process does not match the stored process.");
  80     return false;
  81   }
  82
  83   if (process->GetState() != lldb::eStateStopped) {
  84     diagnostic_manager.Printf(lldb::eSeverityError, "process is not stopped");
  85     return false;
  86   }
  87
  88   if (!m_compiled) {
  89     diagnostic_manager.Printf(lldb::eSeverityError, "function not compiled");
  90     return false;
  91   }
  92
  93   if (m_JITted)
  94     return true;
  95
  96   bool can_interpret = false; // should stay that way
  97
  98   Status jit_error(m_parser->PrepareForExecution(
  99       m_jit_start_addr, m_jit_end_addr, m_execution_unit_sp, exe_ctx,
 100       can_interpret, eExecutionPolicyAlways));
 101
 102   if (!jit_error.Success()) {
 103     diagnostic_manager.Printf(lldb::eSeverityError,
 104                               "Error in PrepareForExecution: %s.",
 105                               jit_error.AsCString());
 106     return false;
 107   }
 108
 109   if (m_parser->GetGenerateDebugInfo()) {
 110     lldb::ModuleSP jit_module_sp(m_execution_unit_sp->GetJITModule());
 111
 112     if (jit_module_sp) {
 113       ConstString const_func_name(FunctionName());
 114       FileSpec jit_file;
 115       jit_file.SetFilename(const_func_name);
 116       jit_module_sp->SetFileSpecAndObjectName(jit_file, ConstString());
 117       m_jit_module_wp = jit_module_sp;
 118       process->GetTarget().GetImages().Append(jit_module_sp,
 119                                               true /* notify */);
 120     }
 121   }
 122   if (process && m_jit_start_addr)
 123     m_jit_process_wp = process->shared_from_this();
 124
 125   m_JITted = true;
 126
 127   return true;
 128 }
 129
 130 bool FunctionCaller::WriteFunctionArguments(
 131     ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
 132     DiagnosticManager &diagnostic_manager) {
 133   return WriteFunctionArguments(exe_ctx, args_addr_ref, m_arg_values,
 134                                 diagnostic_manager);
 135 }
 136
 137 // FIXME: Assure that the ValueList we were passed in is consistent with the one
 138 // that defined this function.
 139
 140 bool FunctionCaller::WriteFunctionArguments(
 141     ExecutionContext &exe_ctx, lldb::addr_t &args_addr_ref,
 142     ValueList &arg_values, DiagnosticManager &diagnostic_manager) {
 143   // All the information to reconstruct the struct is provided by the
 144   // StructExtractor.
 145   if (!m_struct_valid) {
 146     diagnostic_manager.PutString(lldb::eSeverityError,
 147                                  "Argument information was not correctly "
 148                                  "parsed, so the function cannot be called.");
 149     return false;
 150   }
 151
 152   Status error;
 153   lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
 154
 155   Process *process = exe_ctx.GetProcessPtr();
 156
 157   if (process == nullptr)
 158     return return_value;
 159
 160   lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
 161
 162   if (process != jit_process_sp.get())
 163     return false;
 164
 165   if (args_addr_ref == LLDB_INVALID_ADDRESS) {
 166     args_addr_ref = process->AllocateMemory(
 167         m_struct_size, lldb::ePermissionsReadable | lldb::ePermissionsWritable,
 168         error);
 169     if (args_addr_ref == LLDB_INVALID_ADDRESS)
 170       return false;
 171     m_wrapper_args_addrs.push_back(args_addr_ref);
 172   } else {
 173     // Make sure this is an address that we've already handed out.
 174     if (find(m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(),
 175              args_addr_ref) == m_wrapper_args_addrs.end()) {
 176       return false;
 177     }
 178   }
 179
 180   // TODO: verify fun_addr needs to be a callable address
 181   Scalar fun_addr(
 182       m_function_addr.GetCallableLoadAddress(exe_ctx.GetTargetPtr()));
 183   uint64_t first_offset = m_member_offsets[0];
 184   process->WriteScalarToMemory(args_addr_ref + first_offset, fun_addr,
 185                                process->GetAddressByteSize(), error);
 186
 187   // FIXME: We will need to extend this for Variadic functions.
 188
 189   Status value_error;
 190
 191   size_t num_args = arg_values.GetSize();
 192   if (num_args != m_arg_values.GetSize()) {
 193     diagnostic_manager.Printf(
 194         lldb::eSeverityError,
 195         "Wrong number of arguments - was: %" PRIu64 " should be: %" PRIu64 "",
 196         (uint64_t)num_args, (uint64_t)m_arg_values.GetSize());
 197     return false;
 198   }
 199
 200   for (size_t i = 0; i < num_args; i++) {
 201     // FIXME: We should sanity check sizes.
 202
 203     uint64_t offset = m_member_offsets[i + 1]; // Clang sizes are in bytes.
 204     Value *arg_value = arg_values.GetValueAtIndex(i);
 205
 206     // FIXME: For now just do scalars:
 207
 208     // Special case: if it's a pointer, don't do anything (the ABI supports
 209     // passing cstrings)
 210
 211     if (arg_value->GetValueType() == Value::ValueType::HostAddress &&
 212         arg_value->GetContextType() == Value::ContextType::Invalid &&
 213         arg_value->GetCompilerType().IsPointerType())
 214       continue;
 215
 216     const Scalar &arg_scalar = arg_value->ResolveValue(&exe_ctx);
 217
 218     if (!process->WriteScalarToMemory(args_addr_ref + offset, arg_scalar,
 219                                       arg_scalar.GetByteSize(), error))
 220       return false;
 221   }
 222
 223   return true;
 224 }
 225
 226 bool FunctionCaller::InsertFunction(ExecutionContext &exe_ctx,
 227                                     lldb::addr_t &args_addr_ref,
 228                                     DiagnosticManager &diagnostic_manager) {
 229   // Since we might need to call allocate memory and maybe call code to make
 230   // the caller, we need to be stopped.
 231   Process *process = exe_ctx.GetProcessPtr();
 232   if (!process) {
 233     diagnostic_manager.PutString(lldb::eSeverityError, "no process");
 234     return false;
 235   }
 236   if (process->GetState() != lldb::eStateStopped) {
 237     diagnostic_manager.PutString(lldb::eSeverityError, "process running");
 238     return false;
 239   }
 240   if (CompileFunction(exe_ctx.GetThreadSP(), diagnostic_manager) != 0)
 241     return false;
 242   if (!WriteFunctionWrapper(exe_ctx, diagnostic_manager))
 243     return false;
 244   if (!WriteFunctionArguments(exe_ctx, args_addr_ref, diagnostic_manager))
 245     return false;
 246
 247   Log *log = GetLog(LLDBLog::Step);
 248   LLDB_LOGF(log, "Call Address: 0x%" PRIx64 " Struct Address: 0x%" PRIx64 ".\n",
 249             m_jit_start_addr, args_addr_ref);
 250
 251   return true;
 252 }
 253
 254 lldb::ThreadPlanSP FunctionCaller::GetThreadPlanToCallFunction(
 255     ExecutionContext &exe_ctx, lldb::addr_t args_addr,
 256     const EvaluateExpressionOptions &options,
 257     DiagnosticManager &diagnostic_manager) {
 258   Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step));
 259
 260   LLDB_LOGF(log,
 261             "-- [FunctionCaller::GetThreadPlanToCallFunction] Creating "
 262             "thread plan to call function \"%s\" --",
 263             m_name.c_str());
 264
 265   // FIXME: Use the errors Stream for better error reporting.
 266   Thread *thread = exe_ctx.GetThreadPtr();
 267   if (thread == nullptr) {
 268     diagnostic_manager.PutString(
 269         lldb::eSeverityError, "Can't call a function without a valid thread.");
 270     return nullptr;
 271   }
 272
 273   // Okay, now run the function:
 274
 275   Address wrapper_address(m_jit_start_addr);
 276
 277   lldb::addr_t args = {args_addr};
 278
 279   lldb::ThreadPlanSP new_plan_sp(new ThreadPlanCallFunction(
 280       *thread, wrapper_address, CompilerType(), args, options));
 281   new_plan_sp->SetIsControllingPlan(true);
 282   new_plan_sp->SetOkayToDiscard(false);
 283   return new_plan_sp;
 284 }
 285
 286 bool FunctionCaller::FetchFunctionResults(ExecutionContext &exe_ctx,
 287                                           lldb::addr_t args_addr,
 288                                           Value &ret_value) {
 289   // Read the return value - it is the last field in the struct:
 290   // FIXME: How does clang tell us there's no return value?  We need to handle
 291   // that case.
 292   // FIXME: Create our ThreadPlanCallFunction with the return CompilerType, and
 293   // then use GetReturnValueObject
 294   // to fetch the value.  That way we can fetch any values we need.
 295
 296   Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step));
 297
 298   LLDB_LOGF(log,
 299             "-- [FunctionCaller::FetchFunctionResults] Fetching function "
 300             "results for \"%s\"--",
 301             m_name.c_str());
 302
 303   Process *process = exe_ctx.GetProcessPtr();
 304
 305   if (process == nullptr)
 306     return false;
 307
 308   lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
 309
 310   if (process != jit_process_sp.get())
 311     return false;
 312
 313   Status error;
 314   ret_value.GetScalar() = process->ReadUnsignedIntegerFromMemory(
 315       args_addr + m_return_offset, m_return_size, 0, error);
 316
 317   if (error.Fail())
 318     return false;
 319
 320   ret_value.SetCompilerType(m_function_return_type);
 321   ret_value.SetValueType(Value::ValueType::Scalar);
 322   return true;
 323 }
 324
 325 void FunctionCaller::DeallocateFunctionResults(ExecutionContext &exe_ctx,
 326                                                lldb::addr_t args_addr) {
 327   std::list<lldb::addr_t>::iterator pos;
 328   pos = std::find(m_wrapper_args_addrs.begin(), m_wrapper_args_addrs.end(),
 329                   args_addr);
 330   if (pos != m_wrapper_args_addrs.end())
 331     m_wrapper_args_addrs.erase(pos);
 332
 333   exe_ctx.GetProcessRef().DeallocateMemory(args_addr);
 334 }
 335
 336 lldb::ExpressionResults FunctionCaller::ExecuteFunction(
 337     ExecutionContext &exe_ctx, lldb::addr_t *args_addr_ptr,
 338     const EvaluateExpressionOptions &options,
 339     DiagnosticManager &diagnostic_manager, Value &results) {
 340   lldb::ExpressionResults return_value = lldb::eExpressionSetupError;
 341
 342   Debugger *debugger =
 343       exe_ctx.GetTargetPtr() ? &exe_ctx.GetTargetPtr()->GetDebugger() : nullptr;
 344   Progress progress("Calling function", FunctionName(), {}, debugger);
 345
 346   // FunctionCaller::ExecuteFunction execution is always just to get the
 347   // result. Unless explicitly asked for, ignore breakpoints and unwind on
 348   // error.
 349   const bool enable_debugging =
 350       exe_ctx.GetTargetPtr() &&
 351       exe_ctx.GetTargetPtr()->GetDebugUtilityExpression();
 352   EvaluateExpressionOptions real_options = options;
 353   real_options.SetDebug(false); // This halts the expression for debugging.
 354   real_options.SetGenerateDebugInfo(enable_debugging);
 355   real_options.SetUnwindOnError(!enable_debugging);
 356   real_options.SetIgnoreBreakpoints(!enable_debugging);
 357
 358   lldb::addr_t args_addr;
 359
 360   if (args_addr_ptr != nullptr)
 361     args_addr = *args_addr_ptr;
 362   else
 363     args_addr = LLDB_INVALID_ADDRESS;
 364
 365   if (CompileFunction(exe_ctx.GetThreadSP(), diagnostic_manager) != 0)
 366     return lldb::eExpressionSetupError;
 367
 368   if (args_addr == LLDB_INVALID_ADDRESS) {
 369     if (!InsertFunction(exe_ctx, args_addr, diagnostic_manager))
 370       return lldb::eExpressionSetupError;
 371   }
 372
 373   Log *log(GetLog(LLDBLog::Expressions | LLDBLog::Step));
 374
 375   LLDB_LOGF(log,
 376             "== [FunctionCaller::ExecuteFunction] Executing function \"%s\" ==",
 377             m_name.c_str());
 378
 379   lldb::ThreadPlanSP call_plan_sp = GetThreadPlanToCallFunction(
 380       exe_ctx, args_addr, real_options, diagnostic_manager);
 381   if (!call_plan_sp)
 382     return lldb::eExpressionSetupError;
 383
 384   // We need to make sure we record the fact that we are running an expression
 385   // here otherwise this fact will fail to be recorded when fetching an
 386   // Objective-C object description
 387   if (exe_ctx.GetProcessPtr())
 388     exe_ctx.GetProcessPtr()->SetRunningUserExpression(true);
 389
 390   return_value = exe_ctx.GetProcessRef().RunThreadPlan(
 391       exe_ctx, call_plan_sp, real_options, diagnostic_manager);
 392
 393   if (log) {
 394     if (return_value != lldb::eExpressionCompleted) {
 395       LLDB_LOGF(log,
 396                 "== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
 397                 "completed abnormally: %s ==",
 398                 m_name.c_str(), toString(return_value).c_str());
 399     } else {
 400       LLDB_LOGF(log,
 401                 "== [FunctionCaller::ExecuteFunction] Execution of \"%s\" "
 402                 "completed normally ==",
 403                 m_name.c_str());
 404     }
 405   }
 406
 407   if (exe_ctx.GetProcessPtr())
 408     exe_ctx.GetProcessPtr()->SetRunningUserExpression(false);
 409
 410   if (args_addr_ptr != nullptr)
 411     *args_addr_ptr = args_addr;
 412
 413   if (return_value != lldb::eExpressionCompleted)
 414     return return_value;
 415
 416   FetchFunctionResults(exe_ctx, args_addr, results);
 417
 418   if (args_addr_ptr == nullptr)
 419     DeallocateFunctionResults(exe_ctx, args_addr);
 420
 421   return lldb::eExpressionCompleted;
 422 }