clang-tools-extra/clangd/CompileCommands.h

   1 //===--- CompileCommands.h - Manipulation of compile flags -------*- 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 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_COMPILECOMMANDS_H
   9 #define LLVM_CLANG_TOOLS_EXTRA_CLANGD_COMPILECOMMANDS_H
  10
  11 #include "GlobalCompilationDatabase.h"
  12 #include "support/Threading.h"
  13 #include "llvm/ADT/StringMap.h"
  14 #include "llvm/ADT/StringRef.h"
  15 #include "llvm/Support/CommandLine.h"
  16 #include <deque>
  17 #include <optional>
  18 #include <string>
  19 #include <vector>
  20
  21 namespace clang {
  22 namespace clangd {
  23
  24 // CommandMangler transforms compile commands from some external source
  25 // for use in clangd. This means:
  26 //  - running the frontend only, stripping args regarding output files etc
  27 //  - forcing the use of clangd's builtin headers rather than clang's
  28 //  - resolving argv0 as cc1 expects
  29 //  - injecting -isysroot flags on mac as the system clang does
  30 struct CommandMangler {
  31   // Absolute path to clang.
  32   std::optional<std::string> ClangPath;
  33   // Directory containing builtin headers.
  34   std::optional<std::string> ResourceDir;
  35   // Root for searching for standard library (passed to -isysroot).
  36   std::optional<std::string> Sysroot;
  37   SystemIncludeExtractorFn SystemIncludeExtractor;
  38
  39   // A command-mangler that doesn't know anything about the system.
  40   // This is hermetic for unit-tests, but won't work well in production.
  41   static CommandMangler forTests();
  42   // Probe the system and build a command-mangler that knows the toolchain.
  43   //  - try to find clang on $PATH, otherwise fake a path near clangd
  44   //  - find the resource directory installed near clangd
  45   //  - on mac, find clang and isysroot by querying the `xcrun` launcher
  46   static CommandMangler detect();
  47
  48   // `Cmd` may describe compilation of a different file, and will be updated
  49   // for parsing `TargetFile`.
  50   void operator()(tooling::CompileCommand &Cmd,
  51                   llvm::StringRef TargetFile) const;
  52
  53 private:
  54   Memoize<llvm::StringMap<std::string>> ResolvedDrivers;
  55   Memoize<llvm::StringMap<std::string>> ResolvedDriversNoFollow;
  56 };
  57
  58 // Removes args from a command-line in a semantically-aware way.
  59 //
  60 // Internally this builds a large (0.5MB) table of clang options on first use.
  61 // Both strip() and process() are fairly cheap after that.
  62 //
  63 // FIXME: this reimplements much of OptTable, it might be nice to expose more.
  64 // The table-building strategy may not make sense outside clangd.
  65 class ArgStripper {
  66 public:
  67   ArgStripper() = default;
  68   ArgStripper(ArgStripper &&) = default;
  69   ArgStripper(const ArgStripper &) = delete;
  70   ArgStripper &operator=(ArgStripper &&) = default;
  71   ArgStripper &operator=(const ArgStripper &) = delete;
  72
  73   // Adds the arg to the set which should be removed.
  74   //
  75   // Recognized clang flags are stripped semantically. When "-I" is stripped:
  76   //  - so is its value (either as -Ifoo or -I foo)
  77   //  - aliases like --include-directory=foo are also stripped
  78   //  - CL-style /Ifoo will be removed if the args indicate MS-compatible mode
  79   // Compile args not recognized as flags are removed literally, except:
  80   //  - strip("ABC*") will remove any arg with an ABC prefix.
  81   //
  82   // In either case, the -Xclang prefix will be dropped if present.
  83   void strip(llvm::StringRef Arg);
  84   // Remove the targets from a compile command, in-place.
  85   void process(std::vector<std::string> &Args) const;
  86
  87 private:
  88   // Deletion rules, to be checked for each arg.
  89   struct Rule {
  90     llvm::StringRef Text;    // Rule applies only if arg begins with Text.
  91     unsigned char Modes = 0; // Rule applies only in specified driver modes.
  92     uint16_t Priority = 0;   // Lower is better.
  93     uint16_t ExactArgs = 0;  // Num args consumed when Arg == Text.
  94     uint16_t PrefixArgs = 0; // Num args consumed when Arg starts with Text.
  95   };
  96   static llvm::ArrayRef<Rule> rulesFor(llvm::StringRef Arg);
  97   const Rule *matchingRule(llvm::StringRef Arg, unsigned Mode,
  98                            unsigned &ArgCount) const;
  99   llvm::SmallVector<Rule> Rules;
 100   std::deque<std::string> Storage; // Store strings not found in option table.
 101 };
 102
 103 // Renders an argv list, with arguments separated by spaces.
 104 // Where needed, arguments are "quoted" and escaped.
 105 std::string printArgv(llvm::ArrayRef<llvm::StringRef> Args);
 106 std::string printArgv(llvm::ArrayRef<std::string> Args);
 107
 108 } // namespace clangd
 109 } // namespace clang
 110
 111 #endif