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
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(value_if_empty: ""));
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(s: "extern \"C\" void ");
89 m_wrapper_function_text.append(str: m_wrapper_function_name);
90 m_wrapper_function_text.append(s: " (void *input)\n{\n struct ");
91 m_wrapper_function_text.append(str: m_wrapper_struct_name);
92 m_wrapper_function_text.append(s: " \n {\n");
93 m_wrapper_function_text.append(s: " ");
94 m_wrapper_function_text.append(str: return_type_str);
95 m_wrapper_function_text.append(s: " (*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(idx: i)
132 .GetTypeName()
133 .AsCString(value_if_empty: "");
134 } else {
135 CompilerType clang_qual_type =
136 m_arg_values.GetValueAtIndex(idx: i)->GetCompilerType();
137 if (clang_qual_type) {
138 type_name = clang_qual_type.GetTypeName().AsCString(value_if_empty: "");
139 } else {
140 diagnostic_manager.Printf(
141 severity: lldb::eSeverityError,
142 format: "Could not determine type of input value %" PRIu64 ".",
143 (uint64_t)i);
144 return 1;
145 }
146 }
147
148 m_wrapper_function_text.append(str: type_name);
149 if (i < num_args - 1)
150 m_wrapper_function_text.append(s: ", ");
151
152 char arg_buf[32];
153 args_buffer.append(s: " ");
154 args_buffer.append(str: type_name);
155 snprintf(s: arg_buf, maxlen: 31, format: "arg_%" PRIu64, (uint64_t)i);
156 args_buffer.push_back(c: ' ');
157 args_buffer.append(s: arg_buf);
158 args_buffer.append(s: ";\n");
159
160 args_list_buffer.append(s: "__lldb_fn_data->");
161 args_list_buffer.append(s: arg_buf);
162 if (i < num_args - 1)
163 args_list_buffer.append(s: ", ");
164 }
165 m_wrapper_function_text.append(
166 s: ");\n"); // Close off the function calling prototype.
167
168 m_wrapper_function_text.append(str: args_buffer);
169
170 m_wrapper_function_text.append(s: " ");
171 m_wrapper_function_text.append(str: return_type_str);
172 m_wrapper_function_text.append(s: " return_value;");
173 m_wrapper_function_text.append(s: "\n };\n struct ");
174 m_wrapper_function_text.append(str: m_wrapper_struct_name);
175 m_wrapper_function_text.append(s: "* __lldb_fn_data = (struct ");
176 m_wrapper_function_text.append(str: m_wrapper_struct_name);
177 m_wrapper_function_text.append(s: " *) input;\n");
178
179 m_wrapper_function_text.append(
180 s: " __lldb_fn_data->return_value = __lldb_fn_data->fn_ptr (");
181 m_wrapper_function_text.append(str: args_list_buffer);
182 m_wrapper_function_text.append(s: ");\n}\n");
183
184 Log *log = GetLog(mask: 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(p: clang_parser);
196 } else {
197 diagnostic_manager.PutString(severity: lldb::eSeverityError,
198 str: "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 args&: passthrough, args: m_owner.GetWrapperStructName(), args&: m_owner);
217
218 return m_struct_extractor.get();
219}
220

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