clang-tools  10.0.0
CompileCommands.cpp
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1 //===--- CompileCommands.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 "CompileCommands.h"
10 #include "Logger.h"
11 #include "clang/Frontend/CompilerInvocation.h"
12 #include "clang/Tooling/ArgumentsAdjusters.h"
13 #include "llvm/Support/FileSystem.h"
14 #include "llvm/Support/FileUtilities.h"
15 #include "llvm/Support/MemoryBuffer.h"
16 #include "llvm/Support/Path.h"
17 #include "llvm/Support/Program.h"
18 
19 namespace clang {
20 namespace clangd {
21 namespace {
22 
23 // Query apple's `xcrun` launcher, which is the source of truth for "how should"
24 // clang be invoked on this system.
25 llvm::Optional<std::string> queryXcrun(llvm::ArrayRef<llvm::StringRef> Argv) {
26  auto Xcrun = llvm::sys::findProgramByName("xcrun");
27  if (!Xcrun) {
28  log("Couldn't find xcrun. Hopefully you have a non-apple toolchain...");
29  return llvm::None;
30  }
31  llvm::SmallString<64> OutFile;
32  llvm::sys::fs::createTemporaryFile("clangd-xcrun", "", OutFile);
33  llvm::FileRemover OutRemover(OutFile);
34  llvm::Optional<llvm::StringRef> Redirects[3] = {
35  /*stdin=*/{""}, /*stdout=*/{OutFile}, /*stderr=*/{""}};
36  vlog("Invoking {0} to find clang installation", *Xcrun);
37  int Ret = llvm::sys::ExecuteAndWait(*Xcrun, Argv,
38  /*Env=*/llvm::None, Redirects,
39  /*SecondsToWait=*/10);
40  if (Ret != 0) {
41  log("xcrun exists but failed with code {0}. "
42  "If you have a non-apple toolchain, this is OK. "
43  "Otherwise, try xcode-select --install.",
44  Ret);
45  return llvm::None;
46  }
47 
48  auto Buf = llvm::MemoryBuffer::getFile(OutFile);
49  if (!Buf) {
50  log("Can't read xcrun output: {0}", Buf.getError().message());
51  return llvm::None;
52  }
53  StringRef Path = Buf->get()->getBuffer().trim();
54  if (Path.empty()) {
55  log("xcrun produced no output");
56  return llvm::None;
57  }
58  return Path.str();
59 }
60 
61 // Resolve symlinks if possible.
62 std::string resolve(std::string Path) {
63  llvm::SmallString<128> Resolved;
64  if (llvm::sys::fs::real_path(Path, Resolved)) {
65  log("Failed to resolve possible symlink {0}", Path);
66  return Path;
67  }
68  return Resolved.str();
69 }
70 
71 // Get a plausible full `clang` path.
72 // This is used in the fallback compile command, or when the CDB returns a
73 // generic driver with no path.
74 std::string detectClangPath() {
75  // The driver and/or cc1 sometimes depend on the binary name to compute
76  // useful things like the standard library location.
77  // We need to emulate what clang on this system is likely to see.
78  // cc1 in particular looks at the "real path" of the running process, and
79  // so if /usr/bin/clang is a symlink, it sees the resolved path.
80  // clangd doesn't have that luxury, so we resolve symlinks ourselves.
81 
82  // On Mac, `which clang` is /usr/bin/clang. It runs `xcrun clang`, which knows
83  // where the real clang is kept. We need to do the same thing,
84  // because cc1 (not the driver!) will find libc++ relative to argv[0].
85 #ifdef __APPLE__
86  if (auto MacClang = queryXcrun({"xcrun", "--find", "clang"}))
87  return resolve(std::move(*MacClang));
88 #endif
89  // On other platforms, just look for compilers on the PATH.
90  for (const char *Name : {"clang", "gcc", "cc"})
91  if (auto PathCC = llvm::sys::findProgramByName(Name))
92  return resolve(std::move(*PathCC));
93  // Fallback: a nonexistent 'clang' binary next to clangd.
94  static int Dummy;
95  std::string ClangdExecutable =
96  llvm::sys::fs::getMainExecutable("clangd", (void *)&Dummy);
97  SmallString<128> ClangPath;
98  ClangPath = llvm::sys::path::parent_path(ClangdExecutable);
99  llvm::sys::path::append(ClangPath, "clang");
100  return ClangPath.str();
101 }
102 
103 // On mac, /usr/bin/clang sets SDKROOT and then invokes the real clang.
104 // The effect of this is to set -isysroot correctly. We do the same.
105 const llvm::Optional<std::string> detectSysroot() {
106 #ifndef __APPLE__
107  return llvm::None;
108 #endif
109 
110  // SDKROOT overridden in environment, respect it. Driver will set isysroot.
111  if (::getenv("SDKROOT"))
112  return llvm::None;
113  return queryXcrun({"xcrun", "--show-sdk-path"});
114  return llvm::None;
115 }
116 
117 std::string detectStandardResourceDir() {
118  static int Dummy; // Just an address in this process.
119  return CompilerInvocation::GetResourcesPath("clangd", (void *)&Dummy);
120 }
121 
122 } // namespace
123 
125  CommandMangler Result;
126  Result.ClangPath = detectClangPath();
127  Result.ResourceDir = detectStandardResourceDir();
128  Result.Sysroot = detectSysroot();
129  return Result;
130 }
131 
133  return CommandMangler();
134 }
135 
136 void CommandMangler::adjust(std::vector<std::string> &Cmd) const {
137  // Check whether the flag exists, either as -flag or -flag=*
138  auto Has = [&](llvm::StringRef Flag) {
139  for (llvm::StringRef Arg : Cmd) {
140  if (Arg.consume_front(Flag) && (Arg.empty() || Arg[0] == '='))
141  return true;
142  }
143  return false;
144  };
145 
146  // clangd should not write files to disk, including dependency files
147  // requested on the command line.
148  Cmd = tooling::getClangStripDependencyFileAdjuster()(Cmd, "");
149  // Strip plugin related command line arguments. Clangd does
150  // not support plugins currently. Therefore it breaks if
151  // compiler tries to load plugins.
152  Cmd = tooling::getStripPluginsAdjuster()(Cmd, "");
153  Cmd = tooling::getClangSyntaxOnlyAdjuster()(Cmd, "");
154 
155  if (ResourceDir && !Has("-resource-dir"))
156  Cmd.push_back(("-resource-dir=" + *ResourceDir));
157 
158  // Don't set `-isysroot` if it is already set or if `--sysroot` is set.
159  // `--sysroot` is a superset of the `-isysroot` argument.
160  if (Sysroot && !Has("-isysroot") && !Has("--sysroot")) {
161  Cmd.push_back("-isysroot");
162  Cmd.push_back(*Sysroot);
163  }
164 
165  // If the driver is a generic name like "g++" with no path, add a clang path.
166  // This makes it easier for us to find the standard libraries on mac.
167  if (ClangPath && llvm::sys::path::is_absolute(*ClangPath) && !Cmd.empty()) {
168  std::string &Driver = Cmd.front();
169  if (Driver == "clang" || Driver == "clang++" || Driver == "gcc" ||
170  Driver == "g++" || Driver == "cc" || Driver == "c++") {
171  llvm::SmallString<128> QualifiedDriver =
172  llvm::sys::path::parent_path(*ClangPath);
173  llvm::sys::path::append(QualifiedDriver, Driver);
174  Driver = QualifiedDriver.str();
175  }
176  }
177 }
178 
179 CommandMangler::operator clang::tooling::ArgumentsAdjuster() {
180  return [Mangler{*this}](const std::vector<std::string> &Args,
181  llvm::StringRef File) {
182  auto Result = Args;
183  Mangler.adjust(Result);
184  return Result;
185  };
186 }
187 
188 } // namespace clangd
189 } // namespace clang
void adjust(std::vector< std::string > &Cmd) const
Documents should not be synced at all.
llvm::Optional< std::string > ClangPath
void vlog(const char *Fmt, Ts &&... Vals)
Definition: Logger.h:67
static CommandMangler forTests()
void log(const char *Fmt, Ts &&... Vals)
Definition: Logger.h:62
std::string Path
A typedef to represent a file path.
Definition: Path.h:20
static constexpr llvm::StringLiteral Name
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
llvm::Optional< std::string > Sysroot
static CommandMangler detect()
llvm::Optional< std::string > ResourceDir