1 //===-- CppModuleConfiguration.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 "CppModuleConfiguration.h"
10
11 #include "ClangHost.h"
12 #include "lldb/Host/FileSystem.h"
13
14 using namespace lldb_private;
15
TrySet(llvm::StringRef path)16 bool CppModuleConfiguration::SetOncePath::TrySet(llvm::StringRef path) {
17 // Setting for the first time always works.
18 if (m_first) {
19 m_path = path.str();
20 m_valid = true;
21 m_first = false;
22 return true;
23 }
24 // Changing the path to the same value is fine.
25 if (m_path == path)
26 return true;
27
28 // Changing the path after it was already set is not allowed.
29 m_valid = false;
30 return false;
31 }
32
analyzeFile(const FileSpec & f)33 bool CppModuleConfiguration::analyzeFile(const FileSpec &f) {
34 using namespace llvm::sys::path;
35 // Convert to slashes to make following operations simpler.
36 std::string dir_buffer = convert_to_slash(f.GetDirectory().GetStringRef());
37 llvm::StringRef posix_dir(dir_buffer);
38
39 // Check for /c++/vX/ that is used by libc++.
40 static llvm::Regex libcpp_regex(R"regex(/c[+][+]/v[0-9]/)regex");
41 // If the path is in the libc++ include directory use it as the found libc++
42 // path. Ignore subdirectories such as /c++/v1/experimental as those don't
43 // need to be specified in the header search.
44 if (libcpp_regex.match(f.GetPath()) &&
45 parent_path(posix_dir, Style::posix).endswith("c++")) {
46 return m_std_inc.TrySet(posix_dir);
47 }
48
49 // Check for /usr/include. On Linux this might be /usr/include/bits, so
50 // we should remove that '/bits' suffix to get the actual include directory.
51 if (posix_dir.endswith("/usr/include/bits"))
52 posix_dir.consume_back("/bits");
53 if (posix_dir.endswith("/usr/include"))
54 return m_c_inc.TrySet(posix_dir);
55
56 // File wasn't interesting, continue analyzing.
57 return true;
58 }
59
60 /// Utility function for just appending two paths.
MakePath(llvm::StringRef lhs,llvm::StringRef rhs)61 static std::string MakePath(llvm::StringRef lhs, llvm::StringRef rhs) {
62 llvm::SmallString<256> result(lhs);
63 llvm::sys::path::append(result, rhs);
64 return std::string(result);
65 }
66
hasValidConfig()67 bool CppModuleConfiguration::hasValidConfig() {
68 // We need to have a C and C++ include dir for a valid configuration.
69 if (!m_c_inc.Valid() || !m_std_inc.Valid())
70 return false;
71
72 // Do some basic sanity checks on the directories that we don't activate
73 // the module when it's clear that it's not usable.
74 const std::vector<std::string> files_to_check = {
75 // * Check that the C library contains at least one random C standard
76 // library header.
77 MakePath(m_c_inc.Get(), "stdio.h"),
78 // * Without a libc++ modulemap file we can't have a 'std' module that
79 // could be imported.
80 MakePath(m_std_inc.Get(), "module.modulemap"),
81 // * Check for a random libc++ header (vector in this case) that has to
82 // exist in a working libc++ setup.
83 MakePath(m_std_inc.Get(), "vector"),
84 };
85
86 for (llvm::StringRef file_to_check : files_to_check) {
87 if (!FileSystem::Instance().Exists(file_to_check))
88 return false;
89 }
90
91 return true;
92 }
93
CppModuleConfiguration(const FileSpecList & support_files)94 CppModuleConfiguration::CppModuleConfiguration(
95 const FileSpecList &support_files) {
96 // Analyze all files we were given to build the configuration.
97 bool error = !llvm::all_of(support_files,
98 std::bind(&CppModuleConfiguration::analyzeFile,
99 this, std::placeholders::_1));
100 // If we have a valid configuration at this point, set the
101 // include directories and module list that should be used.
102 if (!error && hasValidConfig()) {
103 // Calculate the resource directory for LLDB.
104 llvm::SmallString<256> resource_dir;
105 llvm::sys::path::append(resource_dir, GetClangResourceDir().GetPath(),
106 "include");
107 m_resource_inc = std::string(resource_dir.str());
108
109 // This order matches the way Clang orders these directories.
110 m_include_dirs = {m_std_inc.Get().str(), m_resource_inc,
111 m_c_inc.Get().str()};
112 m_imported_modules = {"std"};
113 }
114 }
115