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/ArchSpec.h"
21 #include "lldb/Core/ClangForward.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 class ASTStructExtractor;
31 class ClangExpressionParser;
32 
33 //----------------------------------------------------------------------
34 /// @class ClangFunctionCaller ClangFunctionCaller.h
35 /// "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   friend class ASTStructExtractor;
69 
70   class ClangFunctionCallerHelper : public ClangExpressionHelper {
71   public:
72     ClangFunctionCallerHelper(ClangFunctionCaller &owner) : m_owner(owner) {}
73 
74     ~ClangFunctionCallerHelper() override = default;
75 
76     //------------------------------------------------------------------
77     /// Return the object that the parser should use when resolving external
78     /// values.  May be NULL if everything should be self-contained.
79     //------------------------------------------------------------------
80     ClangExpressionDeclMap *DeclMap() override { return NULL; }
81 
82     //------------------------------------------------------------------
83     /// Return the object that the parser should allow to access ASTs.
84     /// May be NULL if the ASTs do not need to be transformed.
85     ///
86     /// @param[in] passthrough
87     ///     The ASTConsumer that the returned transformer should send
88     ///     the ASTs to after transformation.
89     //------------------------------------------------------------------
90     clang::ASTConsumer *
91     ASTTransformer(clang::ASTConsumer *passthrough) override;
92 
93   private:
94     ClangFunctionCaller &m_owner;
95     std::unique_ptr<ASTStructExtractor> m_struct_extractor; ///< The class that
96                                                             ///generates the
97                                                             ///argument struct
98                                                             ///layout.
99   };
100 
101 public:
102   //------------------------------------------------------------------
103   /// Constructor
104   ///
105   /// @param[in] exe_scope
106   ///     An execution context scope that gets us at least a target and
107   ///     process.
108   ///
109   /// @param[in] ast_context
110   ///     The AST context to evaluate argument types in.
111   ///
112   /// @param[in] return_qualtype
113   ///     An opaque Clang QualType for the function result.  Should be
114   ///     defined in ast_context.
115   ///
116   /// @param[in] function_address
117   ///     The address of the function to call.
118   ///
119   /// @param[in] arg_value_list
120   ///     The default values to use when calling this function.  Can
121   ///     be overridden using WriteFunctionArguments().
122   //------------------------------------------------------------------
123   ClangFunctionCaller(ExecutionContextScope &exe_scope,
124                       const CompilerType &return_type,
125                       const Address &function_address,
126                       const ValueList &arg_value_list, const char *name);
127 
128   ~ClangFunctionCaller() override;
129 
130   //------------------------------------------------------------------
131   /// Compile the wrapper function
132   ///
133   /// @param[in] thread_to_use_sp
134   ///     Compilation might end up calling functions.  Pass in the thread you
135   ///     want the compilation to use.  If you pass in an empty ThreadSP it will
136   ///     use the currently selected thread.
137   ///
138   /// @param[in] diagnostic_manager
139   ///     The diagnostic manager to report parser errors to.
140   ///
141   /// @return
142   ///     The number of errors.
143   //------------------------------------------------------------------
144   unsigned CompileFunction(lldb::ThreadSP thread_to_use_sp,
145                            DiagnosticManager &diagnostic_manager) override;
146 
147   ExpressionTypeSystemHelper *GetTypeSystemHelper() override {
148     return &m_type_system_helper;
149   }
150 
151 protected:
152   const char *GetWrapperStructName() { return m_wrapper_struct_name.c_str(); }
153 
154 private:
155   //------------------------------------------------------------------
156   // For ClangFunctionCaller only
157   //------------------------------------------------------------------
158 
159   // Note: the parser needs to be destructed before the execution unit, so
160   // declare the execution unit first.
161   ClangFunctionCallerHelper m_type_system_helper;
162 };
163 
164 } // namespace lldb_private
165 
166 #endif // liblldb_ClangFunctionCaller_h_
167