blob: a2fdb04ec7b846f2c0a6a400971e4c4da4b57d5c [file] [log] [blame]
//===-- CanonicalIncludes.h - remap #include header -------------*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// At indexing time, we decide which file to #included for a symbol.
// Usually this is the file with the canonical decl, but there are exceptions:
// - private headers may have pragmas pointing to the matching public header.
// (These are "IWYU" pragmas, named after the include-what-you-use tool).
// - the standard library is implemented in many files, without any pragmas.
// We have a lookup table for common standard library implementations.
// libstdc++ puts char_traits in bits/char_traits.h, but we #include <string>.
#include "clang/Lex/Preprocessor.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/Regex.h"
#include <mutex>
#include <string>
#include <vector>
namespace clang {
namespace clangd {
/// Maps a definition location onto an #include file, based on a set of filename
/// rules.
/// Only const methods (i.e. mapHeader) in this class are thread safe.
class CanonicalIncludes {
CanonicalIncludes() = default;
/// Adds a string-to-string mapping from \p Path to \p CanonicalPath.
void addMapping(llvm::StringRef Path, llvm::StringRef CanonicalPath);
/// Maps all files matching \p RE to \p CanonicalPath
void addRegexMapping(llvm::StringRef RE, llvm::StringRef CanonicalPath);
/// Sets the canonical include for any symbol with \p QualifiedName.
/// Symbol mappings take precedence over header mappings.
void addSymbolMapping(llvm::StringRef QualifiedName,
llvm::StringRef CanonicalPath);
/// Returns the canonical include for symbol with \p QualifiedName.
/// \p Headers is the include stack: Headers.front() is the file declaring the
/// symbol, and Headers.back() is the main file.
llvm::StringRef mapHeader(llvm::ArrayRef<std::string> Headers,
llvm::StringRef QualifiedName) const;
// A map from header patterns to header names. This needs to be mutable so
// that we can match again a Regex in a const function member.
// FIXME(ioeric): All the regexes we have so far are suffix matches. The
// performance could be improved by allowing only suffix matches instead of
// arbitrary regexes.
mutable std::vector<std::pair<llvm::Regex, std::string>>
// A map from fully qualified symbol names to header names.
llvm::StringMap<std::string> SymbolMapping;
// Guards Regex matching as it's not thread-safe.
mutable std::mutex RegexMutex;
/// Returns a CommentHandler that parses pragma comment on include files to
/// determine when we should include a different header from the header that
/// directly defines a symbol. Mappinps are registered with \p Includes.
/// Currently it only supports IWYU private pragma:
collectIWYUHeaderMaps(CanonicalIncludes *Includes);
/// Adds mapping for system headers and some special symbols (e.g. STL symbols
/// in <iosfwd> need to be mapped individually). Approximately, the following
/// system headers are handled:
/// - C++ standard library e.g. bits/basic_string.h$ -> <string>
/// - Posix library e.g. bits/pthreadtypes.h$ -> <pthread.h>
/// - Compiler extensions, e.g. include/avx512bwintrin.h$ -> <immintrin.h>
/// The mapping is hardcoded and hand-maintained, so it might not cover all
/// headers.
void addSystemHeadersMapping(CanonicalIncludes *Includes);
} // namespace clangd
} // namespace clang