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