[clang-tools-extra] Add support for renaming objc methods, even those with multiple selector pieces (PR #76466)

[Alex Hoppen via cfe-commits]

================
@@ -538,11 +564,222 @@ std::optional<InvalidName> checkName(const NamedDecl &RenameDecl,
             Conflict->getLocation().printToString(ASTCtx.getSourceManager())};
     }
   }
-  if (Result)
+  if (Result) {
     InvalidNameMetric.record(1, toString(Result->K));
+    return makeError(*Result);
+  }
+  return llvm::Error::success();
+}
+
+bool isSelectorLike(const syntax::Token &Cur, const syntax::Token &Next) {
+  return Cur.kind() == tok::identifier && Next.kind() == tok::colon &&
+         // We require the selector name and : to be contiguous.
+         // e.g. support `foo:` but not `foo :`.
+         Cur.endLocation() == Next.location();
+}
+
+bool isMatchingSelectorName(const syntax::Token &Cur, const syntax::Token &Next,
+                            const SourceManager &SM,
+                            llvm::StringRef SelectorName) {
+  if (SelectorName.empty())
+    return Cur.kind() == tok::colon;
+  return isSelectorLike(Cur, Next) && Cur.text(SM) == SelectorName;
+}
+
+// Scan through Tokens to find ranges for each selector fragment in Sel at the
+// top level (not nested in any () or {} or []). The search will terminate upon
+// seeing Terminator or a ; at the top level.
+std::optional<SymbolRange>
+findAllSelectorPieces(llvm::ArrayRef<syntax::Token> Tokens,
+                      const SourceManager &SM, Selector Sel,
+                      tok::TokenKind Terminator) {
+
+  unsigned NumArgs = Sel.getNumArgs();
+  llvm::SmallVector<tok::TokenKind, 8> Closes;
+  std::vector<Range> SelectorPieces;
+  unsigned Last = Tokens.size() - 1;
+  for (unsigned Index = 0; Index < Last; ++Index) {
+    const auto &Tok = Tokens[Index];
+
+    if (Closes.empty()) {
+      auto PieceCount = SelectorPieces.size();
+      if (PieceCount < NumArgs &&
+          isMatchingSelectorName(Tok, Tokens[Index + 1], SM,
+                                 Sel.getNameForSlot(PieceCount))) {
+        // If 'foo:' instead of ':' (empty selector), we need to skip the ':'
+        // token after the name.
+        if (!Sel.getNameForSlot(PieceCount).empty())
+          ++Index;
+        SelectorPieces.push_back(
+            halfOpenToRange(SM, Tok.range(SM).toCharRange(SM)));
+        continue;
+      }
+      // If we've found all pieces but the current token looks like another
+      // selector piece, it means the method being renamed is a strict prefix of
+      // the selector we've found - should be skipped.
+      if (SelectorPieces.size() >= NumArgs &&
+          isSelectorLike(Tok, Tokens[Index + 1]))
+        return std::nullopt;
+    }
+
+    if (Closes.empty() && Tok.kind() == Terminator)
+      return SelectorPieces.size() == NumArgs
+                 ? std::optional(SymbolRange(SelectorPieces))
+                 : std::nullopt;
+
+    switch (Tok.kind()) {
+    case tok::l_square:
+      Closes.push_back(tok::r_square);
+      break;
+    case tok::l_paren:
+      Closes.push_back(tok::r_paren);
+      break;
+    case tok::l_brace:
+      Closes.push_back(tok::r_brace);
+      break;
+    case tok::r_square:
+    case tok::r_paren:
+    case tok::r_brace:
+      if (Closes.empty() || Closes.back() != Tok.kind())
+        return std::nullopt;
+      Closes.pop_back();
+      break;
+    case tok::semi:
+      // top level ; terminates all statements.
+      if (Closes.empty())
+        return SelectorPieces.size() == NumArgs
+                   ? std::optional(SymbolRange(SelectorPieces))
+                   : std::nullopt;
+      break;
+    default:
+      break;
+    }
+  }
+  return std::nullopt;
+}
+
+/// Collects all ranges of the given identifier/selector in the source code.
+///
+/// If a selector is given, this does a full lex of the given source code in
+/// order to identify all selector fragments (e.g. in method exprs/decls) since
+/// they are non-contiguous.
+std::vector<SymbolRange> collectRenameIdentifierRanges(
+    llvm::StringRef Identifier, llvm::StringRef Content,
+    const LangOptions &LangOpts, std::optional<Selector> Selector) {
+  std::vector<SymbolRange> Ranges;
+  if (!Selector) {
+    auto IdentifierRanges =
+        collectIdentifierRanges(Identifier, Content, LangOpts);
+    for (const auto &R : IdentifierRanges)
+      Ranges.emplace_back(R);
+    return Ranges;
+  }
+  // FIXME: InMemoryFileAdapter crashes unless the buffer is null terminated!
----------------
ahoppen wrote:

In my rename PR I found that this is no longer an issue. See https://github.com/apple/llvm-project/pull/7915#discussion_r1442402332

https://github.com/llvm/llvm-project/pull/76466