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