xref: /llvm-project/clang-tools-extra/clangd/CompileCommands.h (revision 73cf485151190fc61bf3cff996fe8ee3eea3a257)
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
112