clang-tools-extra/clang-tidy/utils/NamespaceAliaser.cpp

   1 //===---------- NamespaceAliaser.cpp - clang-tidy -------------------------===//
   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 "NamespaceAliaser.h"
  10
  11 #include "ASTUtils.h"
  12 #include "clang/ASTMatchers/ASTMatchFinder.h"
  13 #include "clang/ASTMatchers/ASTMatchers.h"
  14 #include "clang/Lex/Lexer.h"
  15 #include <optional>
  16 namespace clang::tidy::utils {
  17
  18 using namespace ast_matchers;
  19
  20 NamespaceAliaser::NamespaceAliaser(const SourceManager &SourceMgr)
  21     : SourceMgr(SourceMgr) {}
  22
  23 AST_MATCHER_P(NamespaceAliasDecl, hasTargetNamespace,
  24               ast_matchers::internal::Matcher<NamespaceDecl>, innerMatcher) {
  25   return innerMatcher.matches(*Node.getNamespace(), Finder, Builder);
  26 }
  27
  28 std::optional<FixItHint>
  29 NamespaceAliaser::createAlias(ASTContext &Context, const Stmt &Statement,
  30                               StringRef Namespace,
  31                               const std::vector<std::string> &Abbreviations) {
  32   const FunctionDecl *Function = getSurroundingFunction(Context, Statement);
  33   if (!Function || !Function->hasBody())
  34     return std::nullopt;
  35
  36   if (AddedAliases[Function].count(Namespace.str()) != 0)
  37     return std::nullopt;
  38
  39   // FIXME: Doesn't consider the order of declarations.
  40   // If we accidentally pick an alias defined later in the function,
  41   // the output won't compile.
  42   // FIXME: Also doesn't consider file or class-scope aliases.
  43
  44   const auto *ExistingAlias = selectFirst<NamedDecl>(
  45       "alias", match(functionDecl(hasBody(compoundStmt(has(declStmt(
  46                          has(namespaceAliasDecl(hasTargetNamespace(hasName(
  47                                                     std::string(Namespace))))
  48                                  .bind("alias"))))))),
  49                      *Function, Context));
  50
  51   if (ExistingAlias != nullptr) {
  52     AddedAliases[Function][Namespace.str()] = ExistingAlias->getName().str();
  53     return std::nullopt;
  54   }
  55
  56   for (const auto &Abbreviation : Abbreviations) {
  57     DeclarationMatcher ConflictMatcher = namedDecl(hasName(Abbreviation));
  58     const auto HasConflictingChildren =
  59         !match(findAll(ConflictMatcher), *Function, Context).empty();
  60     const auto HasConflictingAncestors =
  61         !match(functionDecl(hasAncestor(decl(has(ConflictMatcher)))), *Function,
  62                Context)
  63              .empty();
  64     if (HasConflictingAncestors || HasConflictingChildren)
  65       continue;
  66
  67     std::string Declaration =
  68         (llvm::Twine("\nnamespace ") + Abbreviation + " = " + Namespace + ";")
  69             .str();
  70     SourceLocation Loc =
  71         Lexer::getLocForEndOfToken(Function->getBody()->getBeginLoc(), 0,
  72                                    SourceMgr, Context.getLangOpts());
  73     AddedAliases[Function][Namespace.str()] = Abbreviation;
  74     return FixItHint::CreateInsertion(Loc, Declaration);
  75   }
  76
  77   return std::nullopt;
  78 }
  79
  80 std::string NamespaceAliaser::getNamespaceName(ASTContext &Context,
  81                                                const Stmt &Statement,
  82                                                StringRef Namespace) const {
  83   const auto *Function = getSurroundingFunction(Context, Statement);
  84   auto FunctionAliases = AddedAliases.find(Function);
  85   if (FunctionAliases != AddedAliases.end()) {
  86     if (FunctionAliases->second.count(Namespace) != 0) {
  87       return FunctionAliases->second.find(Namespace)->getValue();
  88     }
  89   }
  90   return Namespace.str();
  91 }
  92
  93 } // namespace clang::tidy::utils