source/Commands/CommandObjectArgs.cpp

//===-- CommandObjectArgs.cpp -----------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// C Includes
// C++ Includes
// Other libraries and framework includes
// Project includes
#include "CommandObjectArgs.h"
#include "Plugins/ExpressionParser/Clang/ClangExpressionVariable.h"
#include "lldb/Core/Debugger.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/Value.h"
#include "lldb/Host/Host.h"
#include "lldb/Host/OptionParser.h"
#include "lldb/Interpreter/Args.h"
#include "lldb/Interpreter/CommandInterpreter.h"
#include "lldb/Interpreter/CommandReturnObject.h"
#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Symbol/Variable.h"
#include "lldb/Target/ABI.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/StackFrame.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"

#include "llvm/ADT/StringSwitch.h"

using namespace lldb;
using namespace lldb_private;

// This command is a toy.  I'm just using it to have a way to construct the
// arguments to
// calling functions.
//

static OptionDefinition g_arg_options[] = {
    // clang-format off
  { LLDB_OPT_SET_1, false, "debug", 'g', OptionParser::eNoArgument, nullptr, nullptr, 0, eArgTypeNone, "Enable verbose debug logging of the expression parsing and evaluation." },
    // clang-format on
};

CommandObjectArgs::CommandOptions::CommandOptions(
    CommandInterpreter &interpreter)
    : Options() {
  // Keep only one place to reset the values to their defaults
  OptionParsingStarting(nullptr);
}

CommandObjectArgs::CommandOptions::~CommandOptions() = default;

Status CommandObjectArgs::CommandOptions::SetOptionValue(
    uint32_t option_idx, llvm::StringRef option_arg,
    ExecutionContext *execution_context) {
  Status error;

  const int short_option = m_getopt_table[option_idx].val;
  error.SetErrorStringWithFormat("invalid short option character '%c'",
                                 short_option);

  return error;
}

void CommandObjectArgs::CommandOptions::OptionParsingStarting(
    ExecutionContext *execution_context) {}

llvm::ArrayRef<OptionDefinition>
CommandObjectArgs::CommandOptions::GetDefinitions() {
  return llvm::makeArrayRef(g_arg_options);
}

CommandObjectArgs::CommandObjectArgs(CommandInterpreter &interpreter)
    : CommandObjectParsed(interpreter, "args",
                          "When stopped at the start of a function, reads "
                          "function arguments of type (u?)int(8|16|32|64)_t, "
                          "(void|char)*",
                          "args"),
      m_options(interpreter) {}

CommandObjectArgs::~CommandObjectArgs() = default;

Options *CommandObjectArgs::GetOptions() { return &m_options; }

bool CommandObjectArgs::DoExecute(Args &args, CommandReturnObject &result) {
  ConstString target_triple;

  Process *process = m_exe_ctx.GetProcessPtr();
  if (!process) {
    result.AppendError("Args found no process.");
    result.SetStatus(eReturnStatusFailed);
    return false;
  }

  const ABI *abi = process->GetABI().get();
  if (!abi) {
    result.AppendError("The current process has no ABI.");
    result.SetStatus(eReturnStatusFailed);
    return false;
  }

  if (args.empty()) {
    result.AppendError("args requires at least one argument");
    result.SetStatus(eReturnStatusFailed);
    return false;
  }

  Thread *thread = m_exe_ctx.GetThreadPtr();

  if (!thread) {
    result.AppendError("args found no thread.");
    result.SetStatus(eReturnStatusFailed);
    return false;
  }

  lldb::StackFrameSP thread_cur_frame = thread->GetSelectedFrame();
  if (!thread_cur_frame) {
    result.AppendError("The current thread has no current frame.");
    result.SetStatus(eReturnStatusFailed);
    return false;
  }

  ModuleSP thread_module_sp(
      thread_cur_frame->GetFrameCodeAddress().GetModule());
  if (!thread_module_sp) {
    result.AppendError("The PC has no associated module.");
    result.SetStatus(eReturnStatusFailed);
    return false;
  }

  TypeSystem *type_system =
      thread_module_sp->GetTypeSystemForLanguage(eLanguageTypeC);
  if (type_system == nullptr) {
    result.AppendError("Unable to create C type system.");
    result.SetStatus(eReturnStatusFailed);
    return false;
  }

  ValueList value_list;

  for (auto &arg_entry : args.entries()) {
    llvm::StringRef arg_type = arg_entry.ref;
    Value value;
    value.SetValueType(Value::eValueTypeScalar);
    CompilerType compiler_type;

    std::size_t int_pos = arg_type.find("int");
    if (int_pos != llvm::StringRef::npos) {
      Encoding encoding = eEncodingSint;

      int width = 0;

      if (int_pos > 1) {
        result.AppendErrorWithFormat("Invalid format: %s.\n",
                                     arg_entry.c_str());
        result.SetStatus(eReturnStatusFailed);
        return false;
      }
      if (int_pos == 1 && arg_type[0] != 'u') {
        result.AppendErrorWithFormat("Invalid format: %s.\n",
                                     arg_entry.c_str());
        result.SetStatus(eReturnStatusFailed);
        return false;
      }
      if (arg_type[0] == 'u') {
        encoding = eEncodingUint;
      }

      llvm::StringRef width_spec = arg_type.drop_front(int_pos + 3);

      auto exp_result = llvm::StringSwitch<llvm::Optional<int>>(width_spec)
                            .Case("8_t", 8)
                            .Case("16_t", 16)
                            .Case("32_t", 32)
                            .Case("64_t", 64)
                            .Default(llvm::None);
      if (!exp_result.hasValue()) {
        result.AppendErrorWithFormat("Invalid format: %s.\n",
                                     arg_entry.c_str());
        result.SetStatus(eReturnStatusFailed);
        return false;
      }
      width = *exp_result;

      compiler_type =
          type_system->GetBuiltinTypeForEncodingAndBitSize(encoding, width);

      if (!compiler_type.IsValid()) {
        result.AppendErrorWithFormat(
            "Couldn't get Clang type for format %s (%s integer, width %d).\n",
            arg_entry.c_str(),
            (encoding == eEncodingSint ? "signed" : "unsigned"), width);

        result.SetStatus(eReturnStatusFailed);
        return false;
      }
    } else if (arg_type == "void*") {
      compiler_type =
          type_system->GetBasicTypeFromAST(eBasicTypeVoid).GetPointerType();
    } else if (arg_type == "char*") {
      compiler_type =
          type_system->GetBasicTypeFromAST(eBasicTypeChar).GetPointerType();
    } else {
      result.AppendErrorWithFormat("Invalid format: %s.\n", arg_entry.c_str());
      result.SetStatus(eReturnStatusFailed);
      return false;
    }

    value.SetCompilerType(compiler_type);
    value_list.PushValue(value);
  }

  if (!abi->GetArgumentValues(*thread, value_list)) {
    result.AppendError("Couldn't get argument values");
    result.SetStatus(eReturnStatusFailed);
    return false;
  }

  result.GetOutputStream().Printf("Arguments : \n");

  for (auto entry : llvm::enumerate(args.entries())) {
    result.GetOutputStream().Printf(
        "%" PRIu64 " (%s): ", (uint64_t)entry.index(), entry.value().c_str());
    value_list.GetValueAtIndex(entry.index())->Dump(&result.GetOutputStream());
    result.GetOutputStream().Printf("\n");
  }

  return result.Succeeded();
}