Index: tools/clang/empty_string/EmptyStringConverter.cpp |
diff --git a/tools/clang/empty_string/EmptyStringConverter.cpp b/tools/clang/empty_string/EmptyStringConverter.cpp |
new file mode 100644 |
index 0000000000000000000000000000000000000000..a9cc4b0c41224735785244a9ec48f59e9b74bcac |
--- /dev/null |
+++ b/tools/clang/empty_string/EmptyStringConverter.cpp |
@@ -0,0 +1,196 @@ |
+// Copyright (c) 2013 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. |
+// |
+// This implements a Clang tool to convert all instances of std::string("") to |
+// std::string(). The latter is more efficient (as std::string doesn't have to |
+// take a copy of an empty string) and generates fewer instructions as well. It |
+// should be run using the tools/clang/scripts/run_tool.py helper. |
+ |
+#include "clang/ASTMatchers/ASTMatchers.h" |
+#include "clang/ASTMatchers/ASTMatchFinder.h" |
+#include "clang/Basic/SourceManager.h" |
+#include "clang/Frontend/FrontendActions.h" |
+#include "clang/Tooling/CommonOptionsParser.h" |
+#include "clang/Tooling/Refactoring.h" |
+#include "clang/Tooling/Tooling.h" |
+#include "llvm/Support/CommandLine.h" |
+ |
+using clang::ast_matchers::MatchFinder; |
+using clang::ast_matchers::argumentCountIs; |
+using clang::ast_matchers::bindTemporaryExpr; |
+using clang::ast_matchers::constructorDecl; |
+using clang::ast_matchers::constructExpr; |
+using clang::ast_matchers::defaultArgExpr; |
+using clang::ast_matchers::expr; |
+using clang::ast_matchers::forEach; |
+using clang::ast_matchers::has; |
+using clang::ast_matchers::hasArgument; |
+using clang::ast_matchers::hasDeclaration; |
+using clang::ast_matchers::hasName; |
+using clang::ast_matchers::id; |
+using clang::ast_matchers::methodDecl; |
+using clang::ast_matchers::newExpr; |
+using clang::ast_matchers::ofClass; |
+using clang::ast_matchers::stringLiteral; |
+using clang::ast_matchers::varDecl; |
+using clang::tooling::CommonOptionsParser; |
+using clang::tooling::Replacement; |
+using clang::tooling::Replacements; |
+ |
+namespace { |
+ |
+// Handles replacements for stack and heap-allocated instances, e.g.: |
+// std::string a(""); |
+// std::string* b = new std::string(""); |
+class ConstructorCallback : public MatchFinder::MatchCallback { |
+ public: |
+ ConstructorCallback(Replacements* replacements) |
+ : replacements_(replacements) {} |
+ |
+ virtual void run(const MatchFinder::MatchResult& result) LLVM_OVERRIDE; |
+ |
+ private: |
+ Replacements* const replacements_; |
+}; |
+ |
+// Handles replacements for invocations of std::string("") in an initializer |
+// list. |
+class InitializerCallback : public MatchFinder::MatchCallback { |
+ public: |
+ InitializerCallback(Replacements* replacements) |
+ : replacements_(replacements) {} |
+ |
+ virtual void run(const MatchFinder::MatchResult& result) LLVM_OVERRIDE; |
+ |
+ private: |
+ Replacements* const replacements_; |
+}; |
+ |
+// Handles replacements for invocations of std::string("") in a temporary |
+// context, e.g. FunctionThatTakesString(std::string("")). Note that this |
+// handles implicits construction of std::string as well. |
+class TemporaryCallback : public MatchFinder::MatchCallback { |
+ public: |
+ TemporaryCallback(Replacements* replacements) : replacements_(replacements) {} |
+ |
+ virtual void run(const MatchFinder::MatchResult& result) LLVM_OVERRIDE; |
+ |
+ private: |
+ Replacements* const replacements_; |
+}; |
+ |
+class EmptyStringConverter { |
+ public: |
+ explicit EmptyStringConverter(Replacements* replacements) |
+ : constructor_callback_(replacements), |
+ initializer_callback_(replacements), |
+ temporary_callback_(replacements) {} |
+ |
+ void SetupMatchers(MatchFinder* match_finder); |
+ |
+ private: |
+ ConstructorCallback constructor_callback_; |
+ InitializerCallback initializer_callback_; |
+ TemporaryCallback temporary_callback_; |
+}; |
+ |
+void EmptyStringConverter::SetupMatchers(MatchFinder* match_finder) { |
+ const auto& constructor_call = |
tfarina
2013/04/08 01:17:37
Unfortunatelly I got the following error when runn
|
+ id("call", |
+ constructExpr( |
+ hasDeclaration(methodDecl(ofClass(hasName("std::basic_string")))), |
+ argumentCountIs(2), |
+ hasArgument(0, id("literal", stringLiteral())), |
+ hasArgument(1, defaultArgExpr()))); |
+ |
+ // Note that expr(has()) in the matcher is significant; the Clang AST wraps |
+ // calls to the std::string constructor with exprWithCleanups nodes. Without |
+ // the expr(has()) matcher, the first and last rules would not match anything! |
+ match_finder->addMatcher(varDecl(forEach(expr(has(constructor_call)))), |
+ &constructor_callback_); |
+ match_finder->addMatcher(newExpr(has(constructor_call)), |
+ &constructor_callback_); |
+ match_finder->addMatcher(bindTemporaryExpr(has(constructor_call)), |
+ &temporary_callback_); |
+ match_finder->addMatcher( |
+ constructorDecl(forEach(expr(has(constructor_call)))), |
+ &initializer_callback_); |
+} |
+ |
+void ConstructorCallback::run(const MatchFinder::MatchResult& result) { |
+ const clang::StringLiteral* literal = |
+ result.Nodes.getNodeAs<clang::StringLiteral>("literal"); |
+ if (literal->getLength() > 0) |
+ return; |
+ |
+ const clang::CXXConstructExpr* call = |
+ result.Nodes.getNodeAs<clang::CXXConstructExpr>("call"); |
+ clang::CharSourceRange range = |
+ clang::CharSourceRange::getTokenRange(call->getParenRange()); |
+ replacements_->insert(Replacement(*result.SourceManager, range, "")); |
+} |
+ |
+void InitializerCallback::run(const MatchFinder::MatchResult& result) { |
+ const clang::StringLiteral* literal = |
+ result.Nodes.getNodeAs<clang::StringLiteral>("literal"); |
+ if (literal->getLength() > 0) |
+ return; |
+ |
+ const clang::CXXConstructExpr* call = |
+ result.Nodes.getNodeAs<clang::CXXConstructExpr>("call"); |
+ replacements_->insert(Replacement(*result.SourceManager, call, "")); |
+} |
+ |
+void TemporaryCallback::run(const MatchFinder::MatchResult& result) { |
+ const clang::StringLiteral* literal = |
+ result.Nodes.getNodeAs<clang::StringLiteral>("literal"); |
+ if (literal->getLength() > 0) |
+ return; |
+ |
+ const clang::CXXConstructExpr* call = |
+ result.Nodes.getNodeAs<clang::CXXConstructExpr>("call"); |
+ // Differentiate between explicit and implicit calls to std::string's |
+ // constructor. An implicitly generated constructor won't have a valid |
+ // source range for the parenthesis. |
+ clang::SourceRange range = call->getParenRange(); |
+ if (range.isValid()) { |
+ replacements_->insert(Replacement(*result.SourceManager, literal, "")); |
+ } else { |
+ replacements_->insert( |
+ Replacement(*result.SourceManager, call, "std::string()")); |
+ } |
+} |
+ |
+} // namespace |
+ |
+static llvm::cl::extrahelp common_help(CommonOptionsParser::HelpMessage); |
+ |
+int main(int argc, const char* argv[]) { |
+ CommonOptionsParser options(argc, argv); |
+ clang::tooling::ClangTool tool(options.getCompilations(), |
+ options.getSourcePathList()); |
+ |
+ Replacements replacements; |
+ EmptyStringConverter converter(&replacements); |
+ MatchFinder match_finder; |
+ converter.SetupMatchers(&match_finder); |
+ |
+ int result = |
+ tool.run(clang::tooling::newFrontendActionFactory(&match_finder)); |
+ if (result != 0) |
+ return result; |
+ |
+ // Each replacement line should have the following format: |
+ // r:<file path>:<offset>:<length>:<replacement text> |
+ // Only the <replacement text> field can contain embedded ":" characters. |
+ // TODO(dcheng): Use a more clever serialization. |
+ llvm::outs() << "==== BEGIN EDITS ====\n"; |
+ for (const Replacement& r : replacements) { |
+ llvm::outs() << "r:" << r.getFilePath() << ":" << r.getOffset() << ":" |
+ << r.getLength() << ":" << r.getReplacementText() << "\n"; |
+ } |
+ llvm::outs() << "==== END EDITS ====\n"; |
+ |
+ return 0; |
+} |