1 //===-- ClangUtilityFunction.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 
9 #include "lldb/Host/Config.h"
10 
11 #include "ClangUtilityFunction.h"
12 #include "ClangExpressionDeclMap.h"
13 #include "ClangExpressionParser.h"
14 #include "ClangExpressionSourceCode.h"
15 #include "ClangPersistentVariables.h"
16 
17 #include <cstdio>
18 #if HAVE_SYS_TYPES_H
19 #include <sys/types.h>
20 #endif
21 
22 
23 #include "lldb/Core/Module.h"
24 #include "lldb/Core/StreamFile.h"
25 #include "lldb/Expression/IRExecutionUnit.h"
26 #include "lldb/Host/Host.h"
27 #include "lldb/Target/ExecutionContext.h"
28 #include "lldb/Target/Target.h"
29 #include "lldb/Utility/ConstString.h"
30 #include "lldb/Utility/Log.h"
31 #include "lldb/Utility/Stream.h"
32 
33 using namespace lldb_private;
34 
35 char ClangUtilityFunction::ID;
36 
37 ClangUtilityFunction::ClangUtilityFunction(ExecutionContextScope &exe_scope,
38                                            std::string text, std::string name,
39                                            bool enable_debugging)
40     : UtilityFunction(
41           exe_scope,
42           std::string(ClangExpressionSourceCode::g_expression_prefix) + text +
43               std::string(ClangExpressionSourceCode::g_expression_suffix),
44           std::move(name), enable_debugging) {
45   // Write the source code to a file so that LLDB's source manager can display
46   // it when debugging the code.
47   if (enable_debugging) {
48     int temp_fd = -1;
49     llvm::SmallString<128> result_path;
50     llvm::sys::fs::createTemporaryFile("lldb", "expr", temp_fd, result_path);
51     if (temp_fd != -1) {
52       lldb_private::NativeFile file(temp_fd, File::eOpenOptionWrite, true);
53       text = "#line 1 \"" + std::string(result_path) + "\"\n" + text;
54       size_t bytes_written = text.size();
55       file.Write(text.c_str(), bytes_written);
56       if (bytes_written == text.size()) {
57         // If we successfully wrote the source to a temporary file, replace the
58         // function text with the next text containing the line directive.
59         m_function_text =
60             std::string(ClangExpressionSourceCode::g_expression_prefix) + text +
61             std::string(ClangExpressionSourceCode::g_expression_suffix);
62       }
63       file.Close();
64     }
65   }
66 }
67 
68 ClangUtilityFunction::~ClangUtilityFunction() = default;
69 
70 /// Install the utility function into a process
71 ///
72 /// \param[in] diagnostic_manager
73 ///     A diagnostic manager to report errors and warnings to.
74 ///
75 /// \param[in] exe_ctx
76 ///     The execution context to install the utility function to.
77 ///
78 /// \return
79 ///     True on success (no errors); false otherwise.
80 bool ClangUtilityFunction::Install(DiagnosticManager &diagnostic_manager,
81                                    ExecutionContext &exe_ctx) {
82   if (m_jit_start_addr != LLDB_INVALID_ADDRESS) {
83     diagnostic_manager.PutString(eDiagnosticSeverityWarning,
84                                  "already installed");
85     return false;
86   }
87 
88   ////////////////////////////////////
89   // Set up the target and compiler
90   //
91 
92   Target *target = exe_ctx.GetTargetPtr();
93 
94   if (!target) {
95     diagnostic_manager.PutString(eDiagnosticSeverityError, "invalid target");
96     return false;
97   }
98 
99   Process *process = exe_ctx.GetProcessPtr();
100 
101   if (!process) {
102     diagnostic_manager.PutString(eDiagnosticSeverityError, "invalid process");
103     return false;
104   }
105 
106   //////////////////////////
107   // Parse the expression
108   //
109 
110   bool keep_result_in_memory = false;
111 
112   ResetDeclMap(exe_ctx, keep_result_in_memory);
113 
114   if (!DeclMap()->WillParse(exe_ctx, nullptr)) {
115     diagnostic_manager.PutString(
116         eDiagnosticSeverityError,
117         "current process state is unsuitable for expression parsing");
118     return false;
119   }
120 
121   const bool generate_debug_info = true;
122   ClangExpressionParser parser(exe_ctx.GetBestExecutionContextScope(), *this,
123                                generate_debug_info);
124 
125   unsigned num_errors = parser.Parse(diagnostic_manager);
126 
127   if (num_errors) {
128     ResetDeclMap();
129 
130     return false;
131   }
132 
133   //////////////////////////////////
134   // JIT the output of the parser
135   //
136 
137   bool can_interpret = false; // should stay that way
138 
139   Status jit_error = parser.PrepareForExecution(
140       m_jit_start_addr, m_jit_end_addr, m_execution_unit_sp, exe_ctx,
141       can_interpret, eExecutionPolicyAlways);
142 
143   if (m_jit_start_addr != LLDB_INVALID_ADDRESS) {
144     m_jit_process_wp = process->shared_from_this();
145     if (parser.GetGenerateDebugInfo()) {
146       lldb::ModuleSP jit_module_sp(m_execution_unit_sp->GetJITModule());
147 
148       if (jit_module_sp) {
149         ConstString const_func_name(FunctionName());
150         FileSpec jit_file;
151         jit_file.GetFilename() = const_func_name;
152         jit_module_sp->SetFileSpecAndObjectName(jit_file, ConstString());
153         m_jit_module_wp = jit_module_sp;
154         target->GetImages().Append(jit_module_sp);
155       }
156     }
157   }
158 
159   DeclMap()->DidParse();
160 
161   ResetDeclMap();
162 
163   if (jit_error.Success()) {
164     return true;
165   } else {
166     const char *error_cstr = jit_error.AsCString();
167     if (error_cstr && error_cstr[0]) {
168       diagnostic_manager.Printf(eDiagnosticSeverityError, "%s", error_cstr);
169     } else {
170       diagnostic_manager.PutString(eDiagnosticSeverityError,
171                                    "expression can't be interpreted or run");
172     }
173     return false;
174   }
175 }
176 
177 void ClangUtilityFunction::ClangUtilityFunctionHelper::ResetDeclMap(
178     ExecutionContext &exe_ctx, bool keep_result_in_memory) {
179   std::shared_ptr<ClangASTImporter> ast_importer;
180   auto *state = exe_ctx.GetTargetSP()->GetPersistentExpressionStateForLanguage(
181       lldb::eLanguageTypeC);
182   if (state) {
183     auto *persistent_vars = llvm::cast<ClangPersistentVariables>(state);
184     ast_importer = persistent_vars->GetClangASTImporter();
185   }
186   m_expr_decl_map_up = std::make_unique<ClangExpressionDeclMap>(
187       keep_result_in_memory, nullptr, exe_ctx.GetTargetSP(), ast_importer,
188       nullptr);
189 }
190