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/Core/ValueObject.h"
27#include "lldb/Core/ValueObjectList.h"
28#include "lldb/Expression/IRExecutionUnit.h"
29#include "lldb/Interpreter/CommandReturnObject.h"
30#include "lldb/Symbol/Function.h"
31#include "lldb/Symbol/Type.h"
32#include "lldb/Target/ExecutionContext.h"
33#include "lldb/Target/Process.h"
34#include "lldb/Target/RegisterContext.h"
35#include "lldb/Target/Target.h"
36#include "lldb/Target/Thread.h"
37#include "lldb/Target/ThreadPlan.h"
38#include "lldb/Target/ThreadPlanCallFunction.h"
39#include "lldb/Utility/DataExtractor.h"
40#include "lldb/Utility/LLDBLog.h"
41#include "lldb/Utility/Log.h"
42#include "lldb/Utility/State.h"
43
44using namespace lldb_private;
45
46char ClangFunctionCaller::ID;
47
48// ClangFunctionCaller constructor
49ClangFunctionCaller::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
63ClangFunctionCaller::~ClangFunctionCaller() = default;
64
65unsigned
66
67ClangFunctionCaller::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            eDiagnosticSeverityError,
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(eDiagnosticSeverityError,
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
210char ClangFunctionCaller::ClangFunctionCallerHelper::ID;
211
212clang::ASTConsumer *
213ClangFunctionCaller::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}
220