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/ADT/Triple.h"
21 #include "llvm/ExecutionEngine/ExecutionEngine.h"
22 #include "llvm/IR/Module.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/Log.h"
41 #include "lldb/Utility/State.h"
42
43 using namespace lldb_private;
44
45 char ClangFunctionCaller::ID;
46
47 // ClangFunctionCaller constructor
ClangFunctionCaller(ExecutionContextScope & exe_scope,const CompilerType & return_type,const Address & functionAddress,const ValueList & arg_value_list,const char * name)48 ClangFunctionCaller::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
~ClangFunctionCaller()62 ClangFunctionCaller::~ClangFunctionCaller() {}
63
64 unsigned
65
CompileFunction(lldb::ThreadSP thread_to_use_sp,DiagnosticManager & diagnostic_manager)66 ClangFunctionCaller::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
209 clang::ASTConsumer *
ASTTransformer(clang::ASTConsumer * passthrough)210 ClangFunctionCaller::ClangFunctionCallerHelper::ASTTransformer(
211 clang::ASTConsumer *passthrough) {
212 m_struct_extractor = std::make_unique<ASTStructExtractor>(
213 passthrough, m_owner.GetWrapperStructName(), m_owner);
214
215 return m_struct_extractor.get();
216 }
217