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