lldb/source/Plugins/ExpressionParser/Clang/ClangFunctionCaller.cpp

   1 //===-- ClangFunctionCaller.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 "ClangFunctionCaller.h"
  10
  11 #include "ASTStructExtractor.h"
  12 #include "ClangExpressionParser.h"
  13
  14 #include "clang/AST/ASTContext.h"
  15 #include "clang/AST/RecordLayout.h"
  16 #include "clang/CodeGen/CodeGenAction.h"
  17 #include "clang/CodeGen/ModuleBuilder.h"
  18 #include "clang/Frontend/CompilerInstance.h"
  19 #include "llvm/ADT/StringRef.h"
  20 #include "llvm/ExecutionEngine/ExecutionEngine.h"
  21 #include "llvm/IR/Module.h"
  22 #include "llvm/TargetParser/Triple.h"
  23
  24 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
  25 #include "lldb/Core/Module.h"
  26 #include "lldb/Expression/IRExecutionUnit.h"
  27 #include "lldb/Interpreter/CommandReturnObject.h"
  28 #include "lldb/Symbol/Function.h"
  29 #include "lldb/Symbol/Type.h"
  30 #include "lldb/Target/ExecutionContext.h"
  31 #include "lldb/Target/Process.h"
  32 #include "lldb/Target/RegisterContext.h"
  33 #include "lldb/Target/Target.h"
  34 #include "lldb/Target/Thread.h"
  35 #include "lldb/Target/ThreadPlan.h"
  36 #include "lldb/Target/ThreadPlanCallFunction.h"
  37 #include "lldb/Utility/DataExtractor.h"
  38 #include "lldb/Utility/LLDBLog.h"
  39 #include "lldb/Utility/Log.h"
  40 #include "lldb/Utility/State.h"
  41 #include "lldb/ValueObject/ValueObject.h"
  42 #include "lldb/ValueObject/ValueObjectList.h"
  43
  44 using namespace lldb_private;
  45
  46 char ClangFunctionCaller::ID;
  47
  48 // ClangFunctionCaller constructor
  49 ClangFunctionCaller::ClangFunctionCaller(ExecutionContextScope &exe_scope,
  50                                          const CompilerType &return_type,
  51                                          const Address &functionAddress,
  52                                          const ValueList &arg_value_list,
  53                                          const char *name)
  54     : FunctionCaller(exe_scope, return_type, functionAddress, arg_value_list,
  55                      name),
  56       m_type_system_helper(*this) {
  57   m_jit_process_wp = lldb::ProcessWP(exe_scope.CalculateProcess());
  58   // Can't make a ClangFunctionCaller without a process.
  59   assert(m_jit_process_wp.lock());
  60 }
  61
  62 // Destructor
  63 ClangFunctionCaller::~ClangFunctionCaller() = default;
  64
  65 unsigned
  66
  67 ClangFunctionCaller::CompileFunction(lldb::ThreadSP thread_to_use_sp,
  68                                      DiagnosticManager &diagnostic_manager) {
  69   if (m_compiled)
  70     return 0;
  71
  72   // Compilation might call code, make sure to keep on the thread the caller
  73   // indicated.
  74   ThreadList::ExpressionExecutionThreadPusher execution_thread_pusher(
  75       thread_to_use_sp);
  76
  77   // FIXME: How does clang tell us there's no return value?  We need to handle
  78   // that case.
  79   unsigned num_errors = 0;
  80
  81   std::string return_type_str(
  82       m_function_return_type.GetTypeName().AsCString(""));
  83
  84   // Cons up the function we're going to wrap our call in, then compile it...
  85   // We declare the function "extern "C"" because the compiler might be in C++
  86   // mode which would mangle the name and then we couldn't find it again...
  87   m_wrapper_function_text.clear();
  88   m_wrapper_function_text.append("extern \"C\" void ");
  89   m_wrapper_function_text.append(m_wrapper_function_name);
  90   m_wrapper_function_text.append(" (void *input)\n{\n    struct ");
  91   m_wrapper_function_text.append(m_wrapper_struct_name);
  92   m_wrapper_function_text.append(" \n  {\n");
  93   m_wrapper_function_text.append("    ");
  94   m_wrapper_function_text.append(return_type_str);
  95   m_wrapper_function_text.append(" (*fn_ptr) (");
  96
  97   // Get the number of arguments.  If we have a function type and it is
  98   // prototyped, trust that, otherwise use the values we were given.
  99
 100   // FIXME: This will need to be extended to handle Variadic functions.  We'll
 101   // need
 102   // to pull the defined arguments out of the function, then add the types from
 103   // the arguments list for the variable arguments.
 104
 105   uint32_t num_args = UINT32_MAX;
 106   bool trust_function = false;
 107   // GetArgumentCount returns -1 for an unprototyped function.
 108   CompilerType function_clang_type;
 109   if (m_function_ptr) {
 110     function_clang_type = m_function_ptr->GetCompilerType();
 111     if (function_clang_type) {
 112       int num_func_args = function_clang_type.GetFunctionArgumentCount();
 113       if (num_func_args >= 0) {
 114         trust_function = true;
 115         num_args = num_func_args;
 116       }
 117     }
 118   }
 119
 120   if (num_args == UINT32_MAX)
 121     num_args = m_arg_values.GetSize();
 122
 123   std::string args_buffer; // This one stores the definition of all the args in
 124                            // "struct caller".
 125   std::string args_list_buffer; // This one stores the argument list called from
 126                                 // the structure.
 127   for (size_t i = 0; i < num_args; i++) {
 128     std::string type_name;
 129
 130     if (trust_function) {
 131       type_name = function_clang_type.GetFunctionArgumentTypeAtIndex(i)
 132                       .GetTypeName()
 133                       .AsCString("");
 134     } else {
 135       CompilerType clang_qual_type =
 136           m_arg_values.GetValueAtIndex(i)->GetCompilerType();
 137       if (clang_qual_type) {
 138         type_name = clang_qual_type.GetTypeName().AsCString("");
 139       } else {
 140         diagnostic_manager.Printf(
 141             lldb::eSeverityError,
 142             "Could not determine type of input value %" PRIu64 ".",
 143             (uint64_t)i);
 144         return 1;
 145       }
 146     }
 147
 148     m_wrapper_function_text.append(type_name);
 149     if (i < num_args - 1)
 150       m_wrapper_function_text.append(", ");
 151
 152     char arg_buf[32];
 153     args_buffer.append("    ");
 154     args_buffer.append(type_name);
 155     snprintf(arg_buf, 31, "arg_%" PRIu64, (uint64_t)i);
 156     args_buffer.push_back(' ');
 157     args_buffer.append(arg_buf);
 158     args_buffer.append(";\n");
 159
 160     args_list_buffer.append("__lldb_fn_data->");
 161     args_list_buffer.append(arg_buf);
 162     if (i < num_args - 1)
 163       args_list_buffer.append(", ");
 164   }
 165   m_wrapper_function_text.append(
 166       ");\n"); // Close off the function calling prototype.
 167
 168   m_wrapper_function_text.append(args_buffer);
 169
 170   m_wrapper_function_text.append("    ");
 171   m_wrapper_function_text.append(return_type_str);
 172   m_wrapper_function_text.append(" return_value;");
 173   m_wrapper_function_text.append("\n  };\n  struct ");
 174   m_wrapper_function_text.append(m_wrapper_struct_name);
 175   m_wrapper_function_text.append("* __lldb_fn_data = (struct ");
 176   m_wrapper_function_text.append(m_wrapper_struct_name);
 177   m_wrapper_function_text.append(" *) input;\n");
 178
 179   m_wrapper_function_text.append(
 180       "  __lldb_fn_data->return_value = __lldb_fn_data->fn_ptr (");
 181   m_wrapper_function_text.append(args_list_buffer);
 182   m_wrapper_function_text.append(");\n}\n");
 183
 184   Log *log = GetLog(LLDBLog::Expressions);
 185   LLDB_LOGF(log, "Expression: \n\n%s\n\n", m_wrapper_function_text.c_str());
 186
 187   // Okay, now compile this expression
 188
 189   lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
 190   if (jit_process_sp) {
 191     const bool generate_debug_info = true;
 192     auto *clang_parser = new ClangExpressionParser(jit_process_sp.get(), *this,
 193                                                    generate_debug_info);
 194     num_errors = clang_parser->Parse(diagnostic_manager);
 195     m_parser.reset(clang_parser);
 196   } else {
 197     diagnostic_manager.PutString(lldb::eSeverityError,
 198                                  "no process - unable to inject function");
 199     num_errors = 1;
 200   }
 201
 202   m_compiled = (num_errors == 0);
 203
 204   if (!m_compiled)
 205     return num_errors;
 206
 207   return num_errors;
 208 }
 209
 210 char ClangFunctionCaller::ClangFunctionCallerHelper::ID;
 211
 212 clang::ASTConsumer *
 213 ClangFunctionCaller::ClangFunctionCallerHelper::ASTTransformer(
 214     clang::ASTConsumer *passthrough) {
 215   m_struct_extractor = std::make_unique<ASTStructExtractor>(
 216       passthrough, m_owner.GetWrapperStructName(), m_owner);
 217
 218   return m_struct_extractor.get();
 219 }