Skip parameter replacements where old text != old name.

tools/clang/rewrite_to_chrome_style/RewriteToChromeStyle.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Changes Blink-style names to Chrome-style names. Currently transforms:
 //   fields:
 //     int m_operationCount => int operation_count_
 //   variables (including parameters):
 //     int mySuperVariable => int my_super_variable
 //   constants:
@@ skipping 324 matching lines @@
 
   return true;
 }
 
 bool GetNameForDecl(const clang::VarDecl& decl,
                     const clang::ASTContext& context,
                     std::string& name) {
   StringRef original_name = decl.getName();
 
   // Nothing to do for unnamed parameters.
-  if (clang::isa<clang::ParmVarDecl>(decl) && original_name.empty())
-    return false;
+  if (clang::isa<clang::ParmVarDecl>(decl)) {
+    if (original_name.empty())
+      return false;
+
+    // Check if |decl| really covers text of |original_name|.  This might not be
+    // true when specializing a templatized class that had an unnamed parameter
+    // in one of method declarations.

[dcheng, 2016/08/25 04:08:51]

Let's file an upstream bug for this with the test case and reference it here: we
end up matching a ParmVarDecl for an unnamed thingie, but somehow it has a name.

[Łukasz Anforowicz, 2016/08/25 23:32:33]

Done: https://llvm.org/bugs/show_bug.cgi?id=29145

+    clang::SourceLocation loc = decl.getLocation();
+    clang::CharSourceRange range = clang::CharSourceRange::getTokenRange(loc);
+    StringRef old_text = clang::Lexer::getSourceText(
+        range, context.getSourceManager(), context.getLangOpts());
+    if (!loc.isMacroID() && old_text != original_name) {

[dcheng, 2016/08/25 04:08:52]

Add a comment why we want to ignore SourceLocations that are in macros.

[Łukasz Anforowicz, 2016/08/25 23:32:33]

I've started using spelling location in the latest patchset - this lets me also
remove isMacroID call.  So - the comment above is no longer applicable.

+      return false;
+    }
+  }
 
   // static class members match against VarDecls. Blink style dictates that
   // these should be prefixed with `s_`, so strip that off. Also check for `m_`
   // and strip that off too, for code that accidentally uses the wrong prefix.
   if (original_name.startswith(kBlinkStaticMemberPrefix))
     original_name = original_name.substr(strlen(kBlinkStaticMemberPrefix));
   else if (original_name.startswith(kBlinkFieldPrefix))
     original_name = original_name.substr(strlen(kBlinkFieldPrefix));
 
   bool is_const = IsProbablyConst(decl, context);
@@ skipping 522 matching lines @@
   for (const auto& r : replacements) {
     std::string replacement_text = r.getReplacementText().str();
     std::replace(replacement_text.begin(), replacement_text.end(), '\n', '\0');
     llvm::outs() << "r:::" << r.getFilePath() << ":::" << r.getOffset()
                  << ":::" << r.getLength() << ":::" << replacement_text << "\n";
   }
   llvm::outs() << "==== END EDITS ====\n";
 
   return 0;
 }