5 files changed, 58 insertions, 6 deletions

diff --git a/clang-tools-extra/clang-rename/USRFinder.cpp b/clang-tools-extra/clang-rename/USRFinder.cpp
index 2c73c879b0a..01f7278dea9 100644
--- a/clang-tools-extra/clang-rename/USRFinder.cpp
+++ b/clang-tools-extra/clang-rename/USRFinder.cpp
@@ -40,6 +40,14 @@ public:
         Point(Point) {
   }
 
+  // \brief Finds the NamedDecl for a name in the source.
+  // \param Name the fully qualified name.
+  explicit NamedDeclFindingASTVisitor(const SourceManager &SourceMgr,
+                                      const std::string &Name)
+      : Result(nullptr), SourceMgr(SourceMgr),
+        Name(Name) {
+  }
+
   // Declaration visitors:
 
   // \brief Checks if the point falls within the NameDecl. This covers every
@@ -93,9 +101,17 @@ private:
   // \returns false on success.
   bool setResult(const NamedDecl *Decl, SourceLocation Start,
                  SourceLocation End) {
-    if (!Start.isValid() || !Start.isFileID() || !End.isValid() ||
-        !End.isFileID() || !isPointWithin(Start, End)) {
-      return true;
+    if (Name.empty()) {
+      // Offset is used to find the declaration.
+      if (!Start.isValid() || !Start.isFileID() || !End.isValid() ||
+          !End.isFileID() || !isPointWithin(Start, End)) {
+        return true;
+      }
+    } else {
+      // Fully qualified name is used to find the declaration.
+      if (Name != Decl->getQualifiedNameAsString()) {
+        return true;
+      }
     }
     Result = Decl;
     return false;
@@ -121,6 +137,7 @@ private:
   const NamedDecl *Result;
   const SourceManager &SourceMgr;
   const SourceLocation Point; // The location to find the NamedDecl.
+  const std::string Name;
 };
 }
 
@@ -148,6 +165,22 @@ const NamedDecl *getNamedDeclAt(const ASTContext &Context,
   return nullptr;
 }
 
+const NamedDecl *getNamedDeclFor(const ASTContext &Context,
+                                 const std::string &Name) {
+  const auto &SourceMgr = Context.getSourceManager();
+  NamedDeclFindingASTVisitor Visitor(SourceMgr, Name);
+  auto Decls = Context.getTranslationUnitDecl()->decls();
+
+  for (auto &CurrDecl : Decls) {
+    Visitor.TraverseDecl(CurrDecl);
+    if (const NamedDecl *Result = Visitor.getNamedDecl()) {
+      return Result;
+    }
+  }
+
+  return nullptr;
+}
+
 std::string getUSRForDecl(const Decl *Decl) {
   llvm::SmallVector<char, 128> Buff;
 
diff --git a/clang-tools-extra/clang-rename/USRFinder.h b/clang-tools-extra/clang-rename/USRFinder.h
index 2de6f4272af..78985b6fc12 100644
--- a/clang-tools-extra/clang-rename/USRFinder.h
+++ b/clang-tools-extra/clang-rename/USRFinder.h
@@ -30,6 +30,12 @@ namespace rename {
 const NamedDecl *getNamedDeclAt(const ASTContext &Context,
                                 const SourceLocation Point);
 
+// Given an AST context and a fully qualified name, returns a NamedDecl
+// identifying the symbol with a matching name. Returns null if nothing is
+// found for the name.
+const NamedDecl *getNamedDeclFor(const ASTContext &Context,
+                                 const std::string &Name);
+
 // Converts a Decl into a USR.
 std::string getUSRForDecl(const Decl *Decl);
 
diff --git a/clang-tools-extra/clang-rename/USRFindingAction.cpp b/clang-tools-extra/clang-rename/USRFindingAction.cpp
index 54b7a38a7c7..0ff0be652b3 100644
--- a/clang-tools-extra/clang-rename/USRFindingAction.cpp
+++ b/clang-tools-extra/clang-rename/USRFindingAction.cpp
@@ -68,7 +68,12 @@ struct NamedDeclFindingConsumer : public ASTConsumer {
         SourceMgr.getMainFileID()).getLocWithOffset(SymbolOffset);
     if (!Point.isValid())
       return;
-    const NamedDecl *FoundDecl = getNamedDeclAt(Context, Point);
+    const NamedDecl *FoundDecl = nullptr;
+    if (OldName.empty()) {
+      FoundDecl = getNamedDeclAt(Context, Point);
+    } else {
+      FoundDecl = getNamedDeclFor(Context, OldName);
+    }
     if (FoundDecl == nullptr) {
       FullSourceLoc FullLoc(Point, SourceMgr);
       errs() << "clang-rename: could not find symbol at "
@@ -96,6 +101,7 @@ struct NamedDeclFindingConsumer : public ASTConsumer {
   }
 
   unsigned SymbolOffset;
+  std::string OldName;
   std::string *SpellingName;
   std::vector<std::string> *USRs;
 };
@@ -106,6 +112,7 @@ USRFindingAction::newASTConsumer() {
       new NamedDeclFindingConsumer);
   SpellingName = "";
   Consumer->SymbolOffset = SymbolOffset;
+  Consumer->OldName = OldName;
   Consumer->USRs = &USRs;
   Consumer->SpellingName = &SpellingName;
   return std::move(Consumer);
diff --git a/clang-tools-extra/clang-rename/USRFindingAction.h b/clang-tools-extra/clang-rename/USRFindingAction.h
index 4c059a56184..a38b37e57db 100644
--- a/clang-tools-extra/clang-rename/USRFindingAction.h
+++ b/clang-tools-extra/clang-rename/USRFindingAction.h
@@ -25,7 +25,7 @@ class NamedDecl;
 namespace rename {
 
 struct USRFindingAction {
-  USRFindingAction(unsigned Offset) : SymbolOffset(Offset) {
+  USRFindingAction(unsigned Offset, const std::string &Name) : SymbolOffset(Offset), OldName(Name) {
   }
   std::unique_ptr<ASTConsumer> newASTConsumer();
 
@@ -40,6 +40,7 @@ struct USRFindingAction {
 
 private:
   unsigned SymbolOffset;
+  std::string OldName;
   std::string SpellingName;
   std::vector<std::string> USRs;
 };
diff --git a/clang-tools-extra/clang-rename/tool/ClangRename.cpp b/clang-tools-extra/clang-rename/tool/ClangRename.cpp
index 92cc9063475..88c25da2f13 100644
--- a/clang-tools-extra/clang-rename/tool/ClangRename.cpp
+++ b/clang-tools-extra/clang-rename/tool/ClangRename.cpp
@@ -52,6 +52,11 @@ SymbolOffset(
     "offset",
     cl::desc("Locates the symbol by offset as opposed to <line>:<column>."),
     cl::cat(ClangRenameCategory));
+static cl::opt<std::string>
+OldName(
+    "old-name",
+    cl::desc("The fully qualified name of the symbol, if -offset is not used."),
+    cl::cat(ClangRenameCategory));
 static cl::opt<bool>
 Inplace(
     "i",
@@ -96,7 +101,7 @@ int main(int argc, const char **argv) {
   // Get the USRs.
   auto Files = OP.getSourcePathList();
   tooling::RefactoringTool Tool(OP.getCompilations(), Files);
-  rename::USRFindingAction USRAction(SymbolOffset);
+  rename::USRFindingAction USRAction(SymbolOffset, OldName);
 
   // Find the USRs.
   Tool.run(tooling::newFrontendActionFactory(&USRAction).get());