1 //===-- ClangExpressionParser.h ---------------------------------*- C++ -*-===//
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 #ifndef liblldb_ClangExpressionParser_h_
10 #define liblldb_ClangExpressionParser_h_
11 
12 #include "lldb/Expression/DiagnosticManager.h"
13 #include "lldb/Expression/ExpressionParser.h"
14 #include "lldb/Utility/ArchSpec.h"
15 #include "lldb/Utility/Status.h"
16 #include "lldb/lldb-public.h"
17 
18 #include <string>
19 #include <vector>
20 
21 namespace llvm {
22 class LLVMContext;
23 }
24 
25 namespace clang {
26 class CodeGenerator;
27 class CodeCompleteConsumer;
28 class CompilerInstance;
29 } // namespace clang
30 
31 namespace lldb_private {
32 
33 class IRExecutionUnit;
34 
35 /// \class ClangExpressionParser ClangExpressionParser.h
36 /// "lldb/Expression/ClangExpressionParser.h" Encapsulates an instance of
37 /// Clang that can parse expressions.
38 ///
39 /// ClangExpressionParser is responsible for preparing an instance of
40 /// ClangExpression for execution.  ClangExpressionParser uses ClangExpression
41 /// as a glorified parameter list, performing the required parsing and
42 /// conversion to formats (DWARF bytecode, or JIT compiled machine code) that
43 /// can be executed.
44 class ClangExpressionParser : public ExpressionParser {
45 public:
46   /// Constructor
47   ///
48   /// Initializes class variables.
49   ///
50   /// \param[in] exe_scope
51   ///     If non-NULL, an execution context scope that can help to
52   ///     correctly create an expression with a valid process for
53   ///     optional tuning Objective-C runtime support. Can be NULL.
54   ///
55   /// \param[in] expr
56   ///     The expression to be parsed.
57   ///
58   /// @param[in] include_directories
59   ///     List of include directories that should be used when parsing the
60   ///     expression.
61   ///
62   /// @param[in] filename
63   ///     Name of the source file that should be used when rendering
64   ///     diagnostics (i.e. errors, warnings or notes from Clang).
65   ClangExpressionParser(ExecutionContextScope *exe_scope, Expression &expr,
66                         bool generate_debug_info,
67                         std::vector<std::string> include_directories = {},
68                         std::string filename = "<clang expression>");
69 
70   /// Destructor
71   ~ClangExpressionParser() override;
72 
73   bool Complete(CompletionRequest &request, unsigned line, unsigned pos,
74                 unsigned typed_pos) override;
75 
76   /// Parse a single expression and convert it to IR using Clang.  Don't wrap
77   /// the expression in anything at all.
78   ///
79   /// \param[in] diagnostic_manager
80   ///     The diagnostic manager to report errors to.
81   ///
82   /// \return
83   ///     The number of errors encountered during parsing.  0 means
84   ///     success.
85   unsigned Parse(DiagnosticManager &diagnostic_manager);
86 
87   bool RewriteExpression(DiagnosticManager &diagnostic_manager) override;
88 
89   /// Ready an already-parsed expression for execution, possibly evaluating it
90   /// statically.
91   ///
92   /// \param[out] func_addr
93   ///     The address to which the function has been written.
94   ///
95   /// \param[out] func_end
96   ///     The end of the function's allocated memory region.  (func_addr
97   ///     and func_end do not delimit an allocated region; the allocated
98   ///     region may begin before func_addr.)
99   ///
100   /// \param[in] execution_unit_sp
101   ///     After parsing, ownership of the execution unit for
102   ///     for the expression is handed to this shared pointer.
103   ///
104   /// \param[in] exe_ctx
105   ///     The execution context to write the function into.
106   ///
107   /// \param[in] execution_policy
108   ///     Determines whether the expression must be JIT-compiled, must be
109   ///     evaluated statically, or whether this decision may be made
110   ///     opportunistically.
111   ///
112   /// \return
113   ///     An error code indicating the success or failure of the operation.
114   ///     Test with Success().
115   Status
116   PrepareForExecution(lldb::addr_t &func_addr, lldb::addr_t &func_end,
117                       lldb::IRExecutionUnitSP &execution_unit_sp,
118                       ExecutionContext &exe_ctx, bool &can_interpret,
119                       lldb_private::ExecutionPolicy execution_policy) override;
120 
121   /// Run all static initializers for an execution unit.
122   ///
123   /// \param[in] execution_unit_sp
124   ///     The execution unit.
125   ///
126   /// \param[in] exe_ctx
127   ///     The execution context to use when running them.  Thread can't be null.
128   ///
129   /// \return
130   ///     The error code indicating the
131   Status RunStaticInitializers(lldb::IRExecutionUnitSP &execution_unit_sp,
132                                ExecutionContext &exe_ctx);
133 
134   /// Returns a string representing current ABI.
135   ///
136   /// \param[in] target_arch
137   ///     The target architecture.
138   ///
139   /// \return
140   ///     A string representing target ABI for the current architecture.
141   std::string GetClangTargetABI(const ArchSpec &target_arch);
142 
143 private:
144   /// Parses the expression.
145   ///
146   /// \param[in] diagnostic_manager
147   ///     The diagnostic manager that should receive the diagnostics
148   ///     from the parsing process.
149   ///
150   /// \param[in] completion
151   ///     The completion consumer that should be used during parsing
152   ///     (or a nullptr if no consumer should be attached).
153   ///
154   /// \param[in] completion_line
155   ///     The line in which the completion marker should be placed.
156   ///     The first line is represented by the value 0.
157   ///
158   /// \param[in] completion_column
159   ///     The column in which the completion marker should be placed.
160   ///     The first column is represented by the value 0.
161   ///
162   /// \return
163   ///    The number of parsing errors.
164   unsigned ParseInternal(DiagnosticManager &diagnostic_manager,
165                          clang::CodeCompleteConsumer *completion = nullptr,
166                          unsigned completion_line = 0,
167                          unsigned completion_column = 0);
168 
169   std::unique_ptr<llvm::LLVMContext>
170       m_llvm_context; ///< The LLVM context to generate IR into
171   std::unique_ptr<clang::CompilerInstance>
172       m_compiler; ///< The Clang compiler used to parse expressions into IR
173   std::unique_ptr<clang::CodeGenerator>
174       m_code_generator; ///< The Clang object that generates IR
175 
176   class LLDBPreprocessorCallbacks;
177   LLDBPreprocessorCallbacks *m_pp_callbacks; ///< Called when the preprocessor
178                                              ///encounters module imports
179   std::unique_ptr<TypeSystemClang> m_ast_context;
180 
181   std::vector<std::string> m_include_directories;
182   /// File name used for the user expression.
183   std::string m_filename;
184 };
185 }
186 
187 #endif // liblldb_ClangExpressionParser_h_
188