1 //===-- ClangFunctionCallerCaller.cpp ---------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "ClangFunctionCaller.h"
11 
12 #include "ASTStructExtractor.h"
13 #include "ClangExpressionParser.h"
14 
15 // C Includes
16 // C++ Includes
17 // Other libraries and framework includes
18 #include "clang/AST/ASTContext.h"
19 #include "clang/AST/RecordLayout.h"
20 #include "clang/CodeGen/CodeGenAction.h"
21 #include "clang/CodeGen/ModuleBuilder.h"
22 #include "clang/Frontend/CompilerInstance.h"
23 #include "llvm/ADT/StringRef.h"
24 #include "llvm/ADT/Triple.h"
25 #include "llvm/ExecutionEngine/ExecutionEngine.h"
26 #include "llvm/IR/Module.h"
27 
28 // Project includes
29 #include "lldb/Core/DataExtractor.h"
30 #include "lldb/Core/Log.h"
31 #include "lldb/Core/Module.h"
32 #include "lldb/Core/State.h"
33 #include "lldb/Core/ValueObject.h"
34 #include "lldb/Core/ValueObjectList.h"
35 #include "lldb/Expression/IRExecutionUnit.h"
36 #include "lldb/Interpreter/CommandReturnObject.h"
37 #include "lldb/Symbol/ClangASTContext.h"
38 #include "lldb/Symbol/Function.h"
39 #include "lldb/Symbol/Type.h"
40 #include "lldb/Target/ExecutionContext.h"
41 #include "lldb/Target/Process.h"
42 #include "lldb/Target/RegisterContext.h"
43 #include "lldb/Target/Target.h"
44 #include "lldb/Target/Thread.h"
45 #include "lldb/Target/ThreadPlan.h"
46 #include "lldb/Target/ThreadPlanCallFunction.h"
47 
48 using namespace lldb_private;
49 
50 //----------------------------------------------------------------------
51 // ClangFunctionCaller constructor
52 //----------------------------------------------------------------------
53 ClangFunctionCaller::ClangFunctionCaller(ExecutionContextScope &exe_scope,
54                                          const CompilerType &return_type,
55                                          const Address &functionAddress,
56                                          const ValueList &arg_value_list,
57                                          const char *name)
58     : FunctionCaller(exe_scope, return_type, functionAddress, arg_value_list,
59                      name),
60       m_type_system_helper(*this) {
61   m_jit_process_wp = lldb::ProcessWP(exe_scope.CalculateProcess());
62   // Can't make a ClangFunctionCaller without a process.
63   assert(m_jit_process_wp.lock());
64 }
65 
66 //----------------------------------------------------------------------
67 // Destructor
68 //----------------------------------------------------------------------
69 ClangFunctionCaller::~ClangFunctionCaller() {}
70 
71 unsigned
72 
73 ClangFunctionCaller::CompileFunction(lldb::ThreadSP thread_to_use_sp,
74                                      DiagnosticManager &diagnostic_manager) {
75   if (m_compiled)
76     return 0;
77 
78   // Compilation might call code, make sure to keep on the thread the caller
79   // indicated.
80   ThreadList::ExpressionExecutionThreadPusher execution_thread_pusher(
81       thread_to_use_sp);
82 
83   // FIXME: How does clang tell us there's no return value?  We need to handle
84   // that case.
85   unsigned num_errors = 0;
86 
87   std::string return_type_str(
88       m_function_return_type.GetTypeName().AsCString(""));
89 
90   // Cons up the function we're going to wrap our call in, then compile it...
91   // We declare the function "extern "C"" because the compiler might be in C++
92   // mode which would mangle the name and then we couldn't find it again...
93   m_wrapper_function_text.clear();
94   m_wrapper_function_text.append("extern \"C\" void ");
95   m_wrapper_function_text.append(m_wrapper_function_name);
96   m_wrapper_function_text.append(" (void *input)\n{\n    struct ");
97   m_wrapper_function_text.append(m_wrapper_struct_name);
98   m_wrapper_function_text.append(" \n  {\n");
99   m_wrapper_function_text.append("    ");
100   m_wrapper_function_text.append(return_type_str);
101   m_wrapper_function_text.append(" (*fn_ptr) (");
102 
103   // Get the number of arguments.  If we have a function type and it is
104   // prototyped,
105   // trust that, otherwise use the values we were given.
106 
107   // FIXME: This will need to be extended to handle Variadic functions.  We'll
108   // need
109   // to pull the defined arguments out of the function, then add the types from
110   // the
111   // arguments list for the variable arguments.
112 
113   uint32_t num_args = UINT32_MAX;
114   bool trust_function = false;
115   // GetArgumentCount returns -1 for an unprototyped function.
116   CompilerType function_clang_type;
117   if (m_function_ptr) {
118     function_clang_type = m_function_ptr->GetCompilerType();
119     if (function_clang_type) {
120       int num_func_args = function_clang_type.GetFunctionArgumentCount();
121       if (num_func_args >= 0) {
122         trust_function = true;
123         num_args = num_func_args;
124       }
125     }
126   }
127 
128   if (num_args == UINT32_MAX)
129     num_args = m_arg_values.GetSize();
130 
131   std::string args_buffer; // This one stores the definition of all the args in
132                            // "struct caller".
133   std::string args_list_buffer; // This one stores the argument list called from
134                                 // the structure.
135   for (size_t i = 0; i < num_args; i++) {
136     std::string type_name;
137 
138     if (trust_function) {
139       type_name = function_clang_type.GetFunctionArgumentTypeAtIndex(i)
140                       .GetTypeName()
141                       .AsCString("");
142     } else {
143       CompilerType clang_qual_type =
144           m_arg_values.GetValueAtIndex(i)->GetCompilerType();
145       if (clang_qual_type) {
146         type_name = clang_qual_type.GetTypeName().AsCString("");
147       } else {
148         diagnostic_manager.Printf(
149             eDiagnosticSeverityError,
150             "Could not determine type of input value %" PRIu64 ".",
151             (uint64_t)i);
152         return 1;
153       }
154     }
155 
156     m_wrapper_function_text.append(type_name);
157     if (i < num_args - 1)
158       m_wrapper_function_text.append(", ");
159 
160     char arg_buf[32];
161     args_buffer.append("    ");
162     args_buffer.append(type_name);
163     snprintf(arg_buf, 31, "arg_%" PRIu64, (uint64_t)i);
164     args_buffer.push_back(' ');
165     args_buffer.append(arg_buf);
166     args_buffer.append(";\n");
167 
168     args_list_buffer.append("__lldb_fn_data->");
169     args_list_buffer.append(arg_buf);
170     if (i < num_args - 1)
171       args_list_buffer.append(", ");
172   }
173   m_wrapper_function_text.append(
174       ");\n"); // Close off the function calling prototype.
175 
176   m_wrapper_function_text.append(args_buffer);
177 
178   m_wrapper_function_text.append("    ");
179   m_wrapper_function_text.append(return_type_str);
180   m_wrapper_function_text.append(" return_value;");
181   m_wrapper_function_text.append("\n  };\n  struct ");
182   m_wrapper_function_text.append(m_wrapper_struct_name);
183   m_wrapper_function_text.append("* __lldb_fn_data = (struct ");
184   m_wrapper_function_text.append(m_wrapper_struct_name);
185   m_wrapper_function_text.append(" *) input;\n");
186 
187   m_wrapper_function_text.append(
188       "  __lldb_fn_data->return_value = __lldb_fn_data->fn_ptr (");
189   m_wrapper_function_text.append(args_list_buffer);
190   m_wrapper_function_text.append(");\n}\n");
191 
192   Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
193   if (log)
194     log->Printf("Expression: \n\n%s\n\n", m_wrapper_function_text.c_str());
195 
196   // Okay, now compile this expression
197 
198   lldb::ProcessSP jit_process_sp(m_jit_process_wp.lock());
199   if (jit_process_sp) {
200     const bool generate_debug_info = true;
201     m_parser.reset(new ClangExpressionParser(jit_process_sp.get(), *this,
202                                              generate_debug_info));
203 
204     num_errors = m_parser->Parse(diagnostic_manager);
205   } else {
206     diagnostic_manager.PutCString(eDiagnosticSeverityError,
207                                   "no process - unable to inject function");
208     num_errors = 1;
209   }
210 
211   m_compiled = (num_errors == 0);
212 
213   if (!m_compiled)
214     return num_errors;
215 
216   return num_errors;
217 }
218 
219 clang::ASTConsumer *
220 ClangFunctionCaller::ClangFunctionCallerHelper::ASTTransformer(
221     clang::ASTConsumer *passthrough) {
222   m_struct_extractor.reset(new ASTStructExtractor(
223       passthrough, m_owner.GetWrapperStructName(), m_owner));
224 
225   return m_struct_extractor.get();
226 }
227