clang/lib/Tooling/Refactoring/Rename/USRFinder.cpp

   1 //===--- USRFinder.cpp - Clang refactoring library ------------------------===//
   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 /// \file Implements a recursive AST visitor that finds the USR of a symbol at a
  10 /// point.
  11 ///
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "clang/Tooling/Refactoring/Rename/USRFinder.h"
  15 #include "clang/AST/AST.h"
  16 #include "clang/AST/ASTContext.h"
  17 #include "clang/AST/RecursiveASTVisitor.h"
  18 #include "clang/Basic/SourceManager.h"
  19 #include "clang/Index/USRGeneration.h"
  20 #include "clang/Lex/Lexer.h"
  21 #include "clang/Tooling/Refactoring/RecursiveSymbolVisitor.h"
  22 #include "llvm/ADT/SmallVector.h"
  23
  24 using namespace llvm;
  25
  26 namespace clang {
  27 namespace tooling {
  28
  29 namespace {
  30
  31 /// Recursively visits each AST node to find the symbol underneath the cursor.
  32 class NamedDeclOccurrenceFindingVisitor
  33     : public RecursiveSymbolVisitor<NamedDeclOccurrenceFindingVisitor> {
  34 public:
  35   // Finds the NamedDecl at a point in the source.
  36   // \param Point the location in the source to search for the NamedDecl.
  37   explicit NamedDeclOccurrenceFindingVisitor(const SourceLocation Point,
  38                                              const ASTContext &Context)
  39       : RecursiveSymbolVisitor(Context.getSourceManager(),
  40                                Context.getLangOpts()),
  41         Point(Point), Context(Context) {}
  42
  43   bool visitSymbolOccurrence(const NamedDecl *ND,
  44                              ArrayRef<SourceRange> NameRanges) {
  45     if (!ND)
  46       return true;
  47     for (const auto &Range : NameRanges) {
  48       SourceLocation Start = Range.getBegin();
  49       SourceLocation End = Range.getEnd();
  50       if (!Start.isValid() || !Start.isFileID() || !End.isValid() ||
  51           !End.isFileID() || !isPointWithin(Start, End))
  52         return true;
  53     }
  54     Result = ND;
  55     return false;
  56   }
  57
  58   const NamedDecl *getNamedDecl() const { return Result; }
  59
  60 private:
  61   // Determines if the Point is within Start and End.
  62   bool isPointWithin(const SourceLocation Start, const SourceLocation End) {
  63     // FIXME: Add tests for Point == End.
  64     return Point == Start || Point == End ||
  65            (Context.getSourceManager().isBeforeInTranslationUnit(Start,
  66                                                                  Point) &&
  67             Context.getSourceManager().isBeforeInTranslationUnit(Point, End));
  68   }
  69
  70   const NamedDecl *Result = nullptr;
  71   const SourceLocation Point; // The location to find the NamedDecl.
  72   const ASTContext &Context;
  73 };
  74
  75 } // end anonymous namespace
  76
  77 const NamedDecl *getNamedDeclAt(const ASTContext &Context,
  78                                 const SourceLocation Point) {
  79   const SourceManager &SM = Context.getSourceManager();
  80   NamedDeclOccurrenceFindingVisitor Visitor(Point, Context);
  81
  82   // Try to be clever about pruning down the number of top-level declarations we
  83   // see. If both start and end is either before or after the point we're
  84   // looking for the point cannot be inside of this decl. Don't even look at it.
  85   for (auto *CurrDecl : Context.getTranslationUnitDecl()->decls()) {
  86     SourceLocation StartLoc = CurrDecl->getBeginLoc();
  87     SourceLocation EndLoc = CurrDecl->getEndLoc();
  88     if (StartLoc.isValid() && EndLoc.isValid() &&
  89         SM.isBeforeInTranslationUnit(StartLoc, Point) !=
  90             SM.isBeforeInTranslationUnit(EndLoc, Point))
  91       Visitor.TraverseDecl(CurrDecl);
  92   }
  93
  94   return Visitor.getNamedDecl();
  95 }
  96
  97 namespace {
  98
  99 /// Recursively visits each NamedDecl node to find the declaration with a
 100 /// specific name.
 101 class NamedDeclFindingVisitor
 102     : public RecursiveASTVisitor<NamedDeclFindingVisitor> {
 103 public:
 104   explicit NamedDeclFindingVisitor(StringRef Name) : Name(Name) {}
 105
 106   // We don't have to traverse the uses to find some declaration with a
 107   // specific name, so just visit the named declarations.
 108   bool VisitNamedDecl(const NamedDecl *ND) {
 109     if (!ND)
 110       return true;
 111     // Fully qualified name is used to find the declaration.
 112     if (Name != ND->getQualifiedNameAsString() &&
 113         Name != "::" + ND->getQualifiedNameAsString())
 114       return true;
 115     Result = ND;
 116     return false;
 117   }
 118
 119   const NamedDecl *getNamedDecl() const { return Result; }
 120
 121 private:
 122   const NamedDecl *Result = nullptr;
 123   StringRef Name;
 124 };
 125
 126 } // end anonymous namespace
 127
 128 const NamedDecl *getNamedDeclFor(const ASTContext &Context,
 129                                  const std::string &Name) {
 130   NamedDeclFindingVisitor Visitor(Name);
 131   Visitor.TraverseDecl(Context.getTranslationUnitDecl());
 132   return Visitor.getNamedDecl();
 133 }
 134
 135 std::string getUSRForDecl(const Decl *Decl) {
 136   llvm::SmallString<128> Buff;
 137
 138   // FIXME: Add test for the nullptr case.
 139   if (Decl == nullptr || index::generateUSRForDecl(Decl, Buff))
 140     return "";
 141
 142   return std::string(Buff);
 143 }
 144
 145 } // end namespace tooling
 146 } // end namespace clang