Make the tool rename identifiers declared in (generated) ComputedStyleBase.h

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 33 matching lines @@
 using namespace clang::ast_matchers;
 using clang::tooling::CommonOptionsParser;
 using clang::tooling::Replacement;
 using llvm::StringRef;
 
 namespace {
 
 const char kBlinkFieldPrefix[] = "m_";
 const char kBlinkStaticMemberPrefix[] = "s_";
 const char kGeneratedFileRegex[] = "^gen/|/gen/";
+const char kGeneratedFileExclusionRegex[] =
+    "(^gen/|/gen/).*/ComputedStyleBase\\.h$";
 const char kGMockMethodNamePrefix[] = "gmock_";
 const char kMethodBlocklistParamName[] = "method-blocklist";
 
 template <typename MatcherType, typename NodeType>
 bool IsMatching(const MatcherType& matcher,
                 const NodeType& node,
                 clang::ASTContext& context) {
   return !match(matcher, node, context).empty();
 }
 
@@ skipping 437 matching lines @@
 
 bool IsKnownTraitName(clang::StringRef name) {
   // This set of names is globally a type trait throughout chromium.
   return name == "safeToCompareToEmptyOrDeleted";
 }
 
 AST_MATCHER(clang::VarDecl, isKnownTraitName) {
   return Node.getDeclName().isIdentifier() && IsKnownTraitName(Node.getName());
 }
 
+AST_MATCHER(clang::Decl, isDeclInGeneratedFile) {
+  // This matcher mimics the built-in isExpansionInFileMatching matcher from
+  // llvm/tools/clang/include/clang/ASTMatchers/ASTMatchers.h, except:
+  // - It special cases some files (e.g. doesn't skip renaming of identifiers
+  //   from gen/blink/core/ComputedStyleBase.h)
+
+  const clang::SourceManager& source_manager =
+      Node.getASTContext().getSourceManager();
+
+  // TODO(lukasza): Consider using getSpellingLoc below.
+  // The built-in isExpansionInFileMatching matcher uses getExpansionLoc below.
+  // We could consider using getSpellingLoc (which properly handles things like
+  // SETTINGS_GETTERS_AND_SETTERS macro which is defined in generated code
+  // (gen/blink/core/SettingsMacros.h), but expanded in non-generated code
+  // (third_party/WebKit/Source/core/frame/Settings.h).
+  clang::SourceLocation loc =
+      source_manager.getExpansionLoc(Node.getLocStart());
+
+  // TODO(lukasza): jump out of scratch space if token concatenation was used.
+  if (loc.isInvalid())
+    return false;
+
+  const clang::FileEntry* file_entry =
+      source_manager.getFileEntryForID(source_manager.getFileID(loc));
+  if (!file_entry)
+    return false;
+
+  static llvm::Regex exclusion_regex(kGeneratedFileExclusionRegex);
+  if (exclusion_regex.match(file_entry->getName()))
+    return false;
+
+  static llvm::Regex generated_file_regex(kGeneratedFileRegex);
+  return generated_file_regex.match(file_entry->getName());
+}
+
 // Helper to convert from a camelCaseName to camel_case_name. It uses some
 // heuristics to try to handle acronyms in camel case names correctly.
 std::string CamelCaseToUnderscoreCase(StringRef input) {
   std::string output;
   bool needs_underscore = false;
   bool was_lowercase = false;
   bool was_uppercase = false;
   bool first_char = true;
   // Iterate in reverse to minimize the amount of backtracking.
   for (const unsigned char* i = input.bytes_end() - 1; i >= input.bytes_begin();
@@ skipping 988 matching lines @@
   //   void WTF::function() {}
   //   void WTF::Class::method() {}
   // matches |WTF::function| and |WTF::Class::method| decls.
   auto decl_has_qualifier_to_blink_namespace =
       declaratorDecl(has(nestedNameSpecifier(
           hasTopLevelPrefix(specifiesNamespace(blink_namespace_decl)))));
 
   auto in_blink_namespace = decl(
       anyOf(decl_under_blink_namespace, decl_has_qualifier_to_blink_namespace,
             hasAncestor(decl_has_qualifier_to_blink_namespace)),
-      unless(hasCanonicalDecl(isExpansionInFileMatching(kGeneratedFileRegex))));
+      unless(hasCanonicalDecl(isDeclInGeneratedFile())));
 
   // Field, variable, and enum declarations ========
   // Given
   //   int x;
   //   struct S {
   //     int y;
   //     enum { VALUE };
   //   };
   // matches |x|, |y|, and |VALUE|.
   auto field_decl_matcher = id("decl", fieldDecl(in_blink_namespace));
@@ skipping 379 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;
 }