1 //===-- ClangFunctionCaller.h -----------------------------------*- 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 #ifndef liblldb_ClangFunctionCaller_h_
11 #define liblldb_ClangFunctionCaller_h_
12 
13 // C Includes
14 // C++ Includes
15 // Other libraries and framework includes
16 // Project includes
17 #include "ClangExpressionHelper.h"
18 
19 #include "lldb/Core/ClangForward.h"
20 #include "lldb/Core/Address.h"
21 #include "lldb/Core/ArchSpec.h"
22 #include "lldb/Core/Value.h"
23 #include "lldb/Core/ValueObjectList.h"
24 #include "lldb/Expression/FunctionCaller.h"
25 #include "lldb/Symbol/CompilerType.h"
26 #include "lldb/Target/Process.h"
27 
28 namespace lldb_private
29 {
30 
31 class ASTStructExtractor;
32 class ClangExpressionParser;
33 
34 //----------------------------------------------------------------------
35 /// @class ClangFunctionCaller ClangFunctionCaller.h "lldb/Expression/ClangFunctionCaller.h"
36 /// @brief Encapsulates a function that can be called.
37 ///
38 /// A given ClangFunctionCaller object can handle a single function signature.
39 /// Once constructed, it can set up any number of concurrent calls to
40 /// functions with that signature.
41 ///
42 /// It performs the call by synthesizing a structure that contains the pointer
43 /// to the function and the arguments that should be passed to that function,
44 /// and producing a special-purpose JIT-compiled function that accepts a void*
45 /// pointing to this struct as its only argument and calls the function in the
46 /// struct with the written arguments.  This method lets Clang handle the
47 /// vagaries of function calling conventions.
48 ///
49 /// The simplest use of the ClangFunctionCaller is to construct it with a
50 /// function representative of the signature you want to use, then call
51 /// ExecuteFunction(ExecutionContext &, Stream &, Value &).
52 ///
53 /// If you need to reuse the arguments for several calls, you can call
54 /// InsertFunction() followed by WriteFunctionArguments(), which will return
55 /// the location of the args struct for the wrapper function in args_addr_ref.
56 ///
57 /// If you need to call the function on the thread plan stack, you can also
58 /// call InsertFunction() followed by GetThreadPlanToCallFunction().
59 ///
60 /// Any of the methods that take arg_addr_ptr or arg_addr_ref can be passed
61 /// a pointer set to LLDB_INVALID_ADDRESS and new structure will be allocated
62 /// and its address returned in that variable.
63 ///
64 /// Any of the methods that take arg_addr_ptr can be passed NULL, and the
65 /// argument space will be managed for you.
66 //----------------------------------------------------------------------
67 class ClangFunctionCaller : public FunctionCaller
68 {
69     friend class ASTStructExtractor;
70 
71     class ClangFunctionCallerHelper : public ClangExpressionHelper
72     {
73     public:
74         ClangFunctionCallerHelper (ClangFunctionCaller &owner) :
75             m_owner(owner)
76         {
77         }
78 
79         ~ClangFunctionCallerHelper() override = default;
80 
81         //------------------------------------------------------------------
82         /// Return the object that the parser should use when resolving external
83         /// values.  May be NULL if everything should be self-contained.
84         //------------------------------------------------------------------
85         ClangExpressionDeclMap *
86         DeclMap() override
87         {
88             return NULL;
89         }
90 
91         //------------------------------------------------------------------
92         /// Return the object that the parser should allow to access ASTs.
93         /// May be NULL if the ASTs do not need to be transformed.
94         ///
95         /// @param[in] passthrough
96         ///     The ASTConsumer that the returned transformer should send
97         ///     the ASTs to after transformation.
98         //------------------------------------------------------------------
99         clang::ASTConsumer *
100         ASTTransformer(clang::ASTConsumer *passthrough) override;
101 
102     private:
103         ClangFunctionCaller                      &m_owner;
104         std::unique_ptr<ASTStructExtractor> m_struct_extractor;         ///< The class that generates the argument struct layout.
105     };
106 
107 public:
108     //------------------------------------------------------------------
109     /// Constructor
110     ///
111     /// @param[in] exe_scope
112     ///     An execution context scope that gets us at least a target and
113     ///     process.
114     ///
115     /// @param[in] ast_context
116     ///     The AST context to evaluate argument types in.
117     ///
118     /// @param[in] return_qualtype
119     ///     An opaque Clang QualType for the function result.  Should be
120     ///     defined in ast_context.
121     ///
122     /// @param[in] function_address
123     ///     The address of the function to call.
124     ///
125     /// @param[in] arg_value_list
126     ///     The default values to use when calling this function.  Can
127     ///     be overridden using WriteFunctionArguments().
128     //------------------------------------------------------------------
129     ClangFunctionCaller (ExecutionContextScope &exe_scope,
130                          const CompilerType &return_type,
131                          const Address& function_address,
132                          const ValueList &arg_value_list,
133                          const char *name);
134 
135     ~ClangFunctionCaller() override;
136 
137     //------------------------------------------------------------------
138     /// Compile the wrapper function
139     ///
140     /// @param[in] thread_to_use_sp
141     ///     Compilation might end up calling functions.  Pass in the thread you
142     ///     want the compilation to use.  If you pass in an empty ThreadSP it will
143     ///     use the currently selected thread.
144     ///
145     /// @param[in] diagnostic_manager
146     ///     The diagnostic manager to report parser errors to.
147     ///
148     /// @return
149     ///     The number of errors.
150     //------------------------------------------------------------------
151     unsigned
152     CompileFunction (lldb::ThreadSP thread_to_use_sp,
153                      DiagnosticManager &diagnostic_manager) override;
154 
155     ExpressionTypeSystemHelper *
156     GetTypeSystemHelper() override
157     {
158         return &m_type_system_helper;
159     }
160 
161 protected:
162     const char *GetWrapperStructName()
163     {
164         return m_wrapper_struct_name.c_str();
165     }
166 
167 private:
168     //------------------------------------------------------------------
169     // For ClangFunctionCaller only
170     //------------------------------------------------------------------
171 
172     // Note: the parser needs to be destructed before the execution unit, so
173     // declare the execution unit first.
174     ClangFunctionCallerHelper   m_type_system_helper;
175 };
176 
177 } // namespace lldb_private
178 
179 #endif // liblldb_ClangFunctionCaller_h_
180