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ClangFunctionCaller.cpp
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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
10
11#include "ASTStructExtractor.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
25#include "lldb/Core/Module.h"
31#include "lldb/Symbol/Type.h"
33#include "lldb/Target/Process.h"
35#include "lldb/Target/Target.h"
36#include "lldb/Target/Thread.h"
41#include "lldb/Utility/Log.h"
42#include "lldb/Utility/State.h"
43
44using namespace lldb_private;
45
47
48// ClangFunctionCaller constructor
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
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(
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...
88 m_wrapper_function_text.append("extern \"C\" void ");
90 m_wrapper_function_text.append(" (void *input)\n{\n struct ");
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 =
137 if (clang_qual_type) {
138 type_name = clang_qual_type.GetTypeName().AsCString("");
139 } else {
140 diagnostic_manager.Printf(
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 }
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 ");
175 m_wrapper_function_text.append("* __lldb_fn_data = (struct ");
177 m_wrapper_function_text.append(" *) input;\n");
178
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
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
210clang::ASTConsumer *
212 clang::ASTConsumer *passthrough) {
213 m_struct_extractor = std::make_unique<ASTStructExtractor>(
214 passthrough, m_owner.GetWrapperStructName(), m_owner);
215
216 return m_struct_extractor.get();
217}
#define LLDB_LOGF(log,...)
Definition: Log.h:344
A section + offset based address class.
Definition: Address.h:59
"lldb/Expression/ClangExpressionParser.h" Encapsulates an instance of Clang that can parse expression...
clang::ASTConsumer * ASTTransformer(clang::ASTConsumer *passthrough) override
Return the object that the parser should allow to access ASTs.
std::unique_ptr< ASTStructExtractor > m_struct_extractor
The class that generates the argument struct layout.
ClangFunctionCaller(ExecutionContextScope &exe_scope, const CompilerType &return_type, const Address &function_address, const ValueList &arg_value_list, const char *name)
Constructor.
unsigned CompileFunction(lldb::ThreadSP thread_to_use_sp, DiagnosticManager &diagnostic_manager) override
Compile the wrapper function.
Generic representation of a type in a programming language.
Definition: CompilerType.h:36
CompilerType GetFunctionArgumentTypeAtIndex(size_t idx) const
ConstString GetTypeName(bool BaseOnly=false) const
int GetFunctionArgumentCount() const
Returns -1 if this isn't a function of if the function doesn't have a prototype Returns a value >= 0 ...
const char * AsCString(const char *value_if_empty=nullptr) const
Get the string value as a C string.
Definition: ConstString.h:192
size_t Printf(DiagnosticSeverity severity, const char *format,...) __attribute__((format(printf
size_t void PutString(DiagnosticSeverity severity, llvm::StringRef str)
"lldb/Target/ExecutionContextScope.h" Inherit from this if your object can reconstruct its execution ...
virtual lldb::ProcessSP CalculateProcess()=0
lldb::ProcessWP m_jit_process_wp
Expression's always have to have a target...
Definition: Expression.h:93
Encapsulates a function that can be called.
std::string m_wrapper_struct_name
The name of the struct that contains the target function address, arguments, and result.
Function * m_function_ptr
The function we're going to call.
ValueList m_arg_values
The default values of the arguments.
std::string m_wrapper_function_name
The name of the wrapper function.
std::string m_wrapper_function_text
The contents of the wrapper function.
CompilerType m_function_return_type
The opaque clang qual type for the function return type.
bool m_compiled
True if the wrapper function has already been parsed.
std::unique_ptr< ExpressionParser > m_parser
The parser responsible for compiling the function.
CompilerType GetCompilerType()
Definition: Function.cpp:521
Value * GetValueAtIndex(size_t idx)
Definition: Value.cpp:670
const CompilerType & GetCompilerType()
Definition: Value.cpp:223
#define UINT32_MAX
Definition: lldb-defines.h:19
A class that represents a running process on the host machine.
Log * GetLog(Cat mask)
Retrieve the Log object for the channel associated with the given log enum.
Definition: Log.h:309