| // 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 rewrite all instances of |
| // scoped_refptr<T>'s implicit cast to T (operator T*) to an explicit call to |
| // the .get() method. |
| |
| #include <assert.h> |
| #include <algorithm> |
| #include <memory> |
| #include <string> |
| |
| #include "clang/AST/ASTContext.h" |
| #include "clang/ASTMatchers/ASTMatchers.h" |
| #include "clang/ASTMatchers/ASTMatchersMacros.h" |
| #include "clang/ASTMatchers/ASTMatchFinder.h" |
| #include "clang/Basic/SourceManager.h" |
| #include "clang/Frontend/FrontendActions.h" |
| #include "clang/Lex/Lexer.h" |
| #include "clang/Tooling/CommonOptionsParser.h" |
| #include "clang/Tooling/Refactoring.h" |
| #include "clang/Tooling/Tooling.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/support/TargetSelect.h" |
| |
| using namespace clang::ast_matchers; |
| using clang::tooling::CommonOptionsParser; |
| using clang::tooling::Replacement; |
| using clang::tooling::Replacements; |
| using llvm::StringRef; |
| |
| namespace clang { |
| namespace ast_matchers { |
| |
| const internal::VariadicDynCastAllOfMatcher<Decl, CXXConversionDecl> |
| conversionDecl; |
| |
| AST_MATCHER(QualType, isBoolean) { |
| return Node->isBooleanType(); |
| } |
| |
| } // namespace ast_matchers |
| } // namespace clang |
| |
| namespace { |
| |
| // Returns true if expr needs to be put in parens (eg: when it is an operator |
| // syntactically). |
| bool NeedsParens(const clang::Expr* expr) { |
| if (llvm::dyn_cast<clang::UnaryOperator>(expr) || |
| llvm::dyn_cast<clang::BinaryOperator>(expr) || |
| llvm::dyn_cast<clang::ConditionalOperator>(expr)) { |
| return true; |
| } |
| // Calls to an overloaded operator also need parens, except for foo(...) and |
| // foo[...] expressions. |
| if (const clang::CXXOperatorCallExpr* op = |
| llvm::dyn_cast<clang::CXXOperatorCallExpr>(expr)) { |
| return op->getOperator() != clang::OO_Call && |
| op->getOperator() != clang::OO_Subscript; |
| } |
| return false; |
| } |
| |
| Replacement RewriteImplicitToExplicitConversion( |
| const MatchFinder::MatchResult& result, |
| const clang::Expr* expr) { |
| clang::CharSourceRange range = clang::CharSourceRange::getTokenRange( |
| result.SourceManager->getSpellingLoc(expr->getLocStart()), |
| result.SourceManager->getSpellingLoc(expr->getLocEnd())); |
| assert(range.isValid() && "Invalid range!"); |
| |
| // Handle cases where an implicit cast is being done by dereferencing a |
| // pointer to a scoped_refptr<> (sadly, it happens...) |
| // |
| // This rewrites both "*foo" and "*(foo)" as "foo->get()". |
| if (const clang::UnaryOperator* op = |
| llvm::dyn_cast<clang::UnaryOperator>(expr)) { |
| if (op->getOpcode() == clang::UO_Deref) { |
| const clang::Expr* const sub_expr = |
| op->getSubExpr()->IgnoreParenImpCasts(); |
| clang::CharSourceRange sub_expr_range = |
| clang::CharSourceRange::getTokenRange( |
| result.SourceManager->getSpellingLoc(sub_expr->getLocStart()), |
| result.SourceManager->getSpellingLoc(sub_expr->getLocEnd())); |
| assert(sub_expr_range.isValid() && "Invalid subexpression range!"); |
| |
| std::string inner_text = clang::Lexer::getSourceText( |
| sub_expr_range, *result.SourceManager, result.Context->getLangOpts()); |
| assert(!inner_text.empty() && "No text for subexpression!"); |
| if (NeedsParens(sub_expr)) { |
| inner_text.insert(0, "("); |
| inner_text.append(")"); |
| } |
| inner_text.append("->get()"); |
| return Replacement(*result.SourceManager, range, inner_text); |
| } |
| } |
| |
| std::string text = clang::Lexer::getSourceText( |
| range, *result.SourceManager, result.Context->getLangOpts()); |
| assert(!text.empty() && "No text for expression!"); |
| |
| // Unwrap any temporaries - for example, custom iterators that return |
| // scoped_refptr<T> as part of operator*. Any such iterators should also |
| // be declaring a scoped_refptr<T>* operator->, per C++03 24.4.1.1 (Table 72) |
| if (const clang::CXXBindTemporaryExpr* op = |
| llvm::dyn_cast<clang::CXXBindTemporaryExpr>(expr)) { |
| expr = op->getSubExpr(); |
| } |
| |
| // Handle iterators (which are operator* calls, followed by implicit |
| // conversions) by rewriting *it as it->get() |
| if (const clang::CXXOperatorCallExpr* op = |
| llvm::dyn_cast<clang::CXXOperatorCallExpr>(expr)) { |
| if (op->getOperator() == clang::OO_Star) { |
| // Note that this doesn't rewrite **it correctly, since it should be |
| // rewritten using parens, e.g. (*it)->get(). However, this shouldn't |
| // happen frequently, if at all, since it would likely indicate code is |
| // storing pointers to a scoped_refptr in a container. |
| text.erase(0, 1); |
| text.append("->get()"); |
| return Replacement(*result.SourceManager, range, text); |
| } |
| } |
| |
| // The only remaining calls should be non-dereferencing calls (eg: member |
| // calls), so a simple ".get()" appending should suffice. |
| if (NeedsParens(expr)) { |
| text.insert(0, "("); |
| text.append(")"); |
| } |
| text.append(".get()"); |
| return Replacement(*result.SourceManager, range, text); |
| } |
| |
| Replacement RewriteRawPtrToScopedRefptr(const MatchFinder::MatchResult& result, |
| clang::SourceLocation begin, |
| clang::SourceLocation end) { |
| clang::CharSourceRange range = clang::CharSourceRange::getTokenRange( |
| result.SourceManager->getSpellingLoc(begin), |
| result.SourceManager->getSpellingLoc(end)); |
| assert(range.isValid() && "Invalid range!"); |
| |
| std::string text = clang::Lexer::getSourceText( |
| range, *result.SourceManager, result.Context->getLangOpts()); |
| text.erase(text.rfind('*')); |
| |
| std::string replacement_text("scoped_refptr<"); |
| replacement_text += text; |
| replacement_text += ">"; |
| |
| return Replacement(*result.SourceManager, range, replacement_text); |
| } |
| |
| class GetRewriterCallback : public MatchFinder::MatchCallback { |
| public: |
| explicit GetRewriterCallback(Replacements* replacements) |
| : replacements_(replacements) {} |
| virtual void run(const MatchFinder::MatchResult& result) override; |
| |
| private: |
| Replacements* const replacements_; |
| }; |
| |
| void GetRewriterCallback::run(const MatchFinder::MatchResult& result) { |
| const clang::Expr* arg = result.Nodes.getNodeAs<clang::Expr>("arg"); |
| assert(arg && "Unexpected match! No Expr captured!"); |
| replacements_->insert(RewriteImplicitToExplicitConversion(result, arg)); |
| } |
| |
| class VarRewriterCallback : public MatchFinder::MatchCallback { |
| public: |
| explicit VarRewriterCallback(Replacements* replacements) |
| : replacements_(replacements) {} |
| virtual void run(const MatchFinder::MatchResult& result) override; |
| |
| private: |
| Replacements* const replacements_; |
| }; |
| |
| void VarRewriterCallback::run(const MatchFinder::MatchResult& result) { |
| const clang::DeclaratorDecl* const var_decl = |
| result.Nodes.getNodeAs<clang::DeclaratorDecl>("var"); |
| assert(var_decl && "Unexpected match! No VarDecl captured!"); |
| |
| const clang::TypeSourceInfo* tsi = var_decl->getTypeSourceInfo(); |
| |
| // TODO(dcheng): This mishandles a case where a variable has multiple |
| // declarations, e.g.: |
| // |
| // in .h: |
| // Foo* my_global_magical_foo; |
| // |
| // in .cc: |
| // Foo* my_global_magical_foo = CreateFoo(); |
| // |
| // In this case, it will only rewrite the .cc definition. Oh well. This should |
| // be rare enough that these cases can be manually handled, since the style |
| // guide prohibits globals of non-POD type. |
| replacements_->insert(RewriteRawPtrToScopedRefptr( |
| result, tsi->getTypeLoc().getBeginLoc(), tsi->getTypeLoc().getEndLoc())); |
| } |
| |
| class FunctionRewriterCallback : public MatchFinder::MatchCallback { |
| public: |
| explicit FunctionRewriterCallback(Replacements* replacements) |
| : replacements_(replacements) {} |
| virtual void run(const MatchFinder::MatchResult& result) override; |
| |
| private: |
| Replacements* const replacements_; |
| }; |
| |
| void FunctionRewriterCallback::run(const MatchFinder::MatchResult& result) { |
| const clang::FunctionDecl* const function_decl = |
| result.Nodes.getNodeAs<clang::FunctionDecl>("fn"); |
| assert(function_decl && "Unexpected match! No FunctionDecl captured!"); |
| |
| // If matched against an implicit conversion to a DeclRefExpr, make sure the |
| // referenced declaration is of class type, e.g. the tool skips trying to |
| // chase pointers/references to determine if the pointee is a scoped_refptr<T> |
| // with local storage. Instead, let a human manually handle those cases. |
| const clang::VarDecl* const var_decl = |
| result.Nodes.getNodeAs<clang::VarDecl>("var"); |
| if (var_decl && !var_decl->getTypeSourceInfo()->getType()->isClassType()) { |
| return; |
| } |
| |
| for (clang::FunctionDecl* f : function_decl->redecls()) { |
| clang::SourceRange range = f->getReturnTypeSourceRange(); |
| replacements_->insert( |
| RewriteRawPtrToScopedRefptr(result, range.getBegin(), range.getEnd())); |
| } |
| } |
| |
| class MacroRewriterCallback : public MatchFinder::MatchCallback { |
| public: |
| explicit MacroRewriterCallback(Replacements* replacements) |
| : replacements_(replacements) {} |
| virtual void run(const MatchFinder::MatchResult& result) override; |
| |
| private: |
| Replacements* const replacements_; |
| }; |
| |
| void MacroRewriterCallback::run(const MatchFinder::MatchResult& result) { |
| const clang::Expr* const expr = result.Nodes.getNodeAs<clang::Expr>("expr"); |
| assert(expr && "Unexpected match! No Expr captured!"); |
| replacements_->insert(RewriteImplicitToExplicitConversion(result, expr)); |
| } |
| |
| } // namespace |
| |
| static llvm::cl::extrahelp common_help(CommonOptionsParser::HelpMessage); |
| |
| int main(int argc, const char* argv[]) { |
| // TODO(dcheng): Clang tooling should do this itself. |
| // http://llvm.org/bugs/show_bug.cgi?id=21627 |
| llvm::InitializeNativeTarget(); |
| llvm::InitializeNativeTargetAsmParser(); |
| llvm::cl::OptionCategory category("Remove scoped_refptr conversions"); |
| CommonOptionsParser options(argc, argv, category); |
| clang::tooling::ClangTool tool(options.getCompilations(), |
| options.getSourcePathList()); |
| |
| MatchFinder match_finder; |
| Replacements replacements; |
| |
| auto is_scoped_refptr = recordDecl(isSameOrDerivedFrom("::scoped_refptr"), |
| isTemplateInstantiation()); |
| |
| // Finds all calls to conversion operator member function. This catches calls |
| // to "operator T*", "operator Testable", and "operator bool" equally. |
| auto base_matcher = memberCallExpr(thisPointerType(is_scoped_refptr), |
| callee(conversionDecl()), |
| on(id("arg", expr()))); |
| |
| // The heuristic for whether or not converting a temporary is 'unsafe'. An |
| // unsafe conversion is one where a temporary scoped_refptr<T> is converted to |
| // another type. The matcher provides an exception for a temporary |
| // scoped_refptr that is the result of an operator call. In this case, assume |
| // that it's the result of an iterator dereference, and the container itself |
| // retains the necessary reference, since this is a common idiom to see in |
| // loop bodies. |
| auto is_unsafe_temporary_conversion = |
| on(bindTemporaryExpr(unless(has(operatorCallExpr())))); |
| |
| // Returning a scoped_refptr<T> as a T* is considered unsafe if either are |
| // true: |
| // - The scoped_refptr<T> is a temporary. |
| // - The scoped_refptr<T> has local lifetime. |
| auto returned_as_raw_ptr = hasParent( |
| returnStmt(hasAncestor(id("fn", functionDecl(returns(pointerType())))))); |
| // This matcher intentionally matches more than it should. For example, this |
| // will match: |
| // scoped_refptr<Foo>& foo = some_other_foo; |
| // return foo; |
| // The matcher callback filters out VarDecls that aren't a scoped_refptr<T>, |
| // so those cases can be manually handled. |
| auto is_local_variable = |
| on(declRefExpr(to(id("var", varDecl(hasLocalStorage()))))); |
| auto is_unsafe_return = |
| anyOf(allOf(hasParent(implicitCastExpr(returned_as_raw_ptr)), |
| is_local_variable), |
| allOf(hasParent(implicitCastExpr( |
| hasParent(exprWithCleanups(returned_as_raw_ptr)))), |
| is_unsafe_temporary_conversion)); |
| |
| // This catches both user-defined conversions (eg: "operator bool") and |
| // standard conversion sequence (C++03 13.3.3.1.1), such as converting a |
| // pointer to a bool. |
| auto implicit_to_bool = |
| implicitCastExpr(hasImplicitDestinationType(isBoolean())); |
| |
| // Avoid converting calls to of "operator Testable" -> "bool" and calls of |
| // "operator T*" -> "bool". |
| auto bool_conversion_matcher = hasParent( |
| expr(anyOf(implicit_to_bool, expr(hasParent(implicit_to_bool))))); |
| |
| auto is_logging_helper = |
| functionDecl(anyOf(hasName("CheckEQImpl"), hasName("CheckNEImpl"))); |
| auto is_gtest_helper = functionDecl( |
| anyOf(methodDecl(ofClass(recordDecl(isSameOrDerivedFrom( |
| hasName("::testing::internal::EqHelper")))), |
| hasName("Compare")), |
| hasName("::testing::internal::CmpHelperNE"))); |
| auto is_gtest_assertion_result_ctor = constructorDecl(ofClass( |
| recordDecl(isSameOrDerivedFrom(hasName("::testing::AssertionResult"))))); |
| |
| // Find all calls to an operator overload that are 'safe'. |
| // |
| // All bool conversions will be handled with the Testable trick, but that |
| // can only be used once "operator T*" is removed, since otherwise it leaves |
| // the call ambiguous. |
| GetRewriterCallback get_callback(&replacements); |
| match_finder.addMatcher( |
| memberCallExpr( |
| base_matcher, |
| // Excluded since the conversion may be unsafe. |
| unless(anyOf(is_unsafe_temporary_conversion, is_unsafe_return)), |
| // Excluded since the conversion occurs inside a helper function that |
| // the macro wraps. Letting this callback handle the rewrite would |
| // result in an incorrect replacement that changes the helper function |
| // itself. Instead, the right replacement is to rewrite the macro's |
| // arguments. |
| unless(hasAncestor(decl(anyOf(is_logging_helper, |
| is_gtest_helper, |
| is_gtest_assertion_result_ctor))))), |
| &get_callback); |
| |
| // Find temporary scoped_refptr<T>'s being unsafely assigned to a T*. |
| VarRewriterCallback var_callback(&replacements); |
| auto initialized_with_temporary = ignoringImpCasts(exprWithCleanups( |
| has(memberCallExpr(base_matcher, is_unsafe_temporary_conversion)))); |
| match_finder.addMatcher(id("var", |
| varDecl(hasInitializer(initialized_with_temporary), |
| hasType(pointerType()))), |
| &var_callback); |
| match_finder.addMatcher( |
| constructorDecl(forEachConstructorInitializer( |
| allOf(withInitializer(initialized_with_temporary), |
| forField(id("var", fieldDecl(hasType(pointerType()))))))), |
| &var_callback); |
| |
| // Rewrite functions that unsafely turn a scoped_refptr<T> into a T* when |
| // returning a value. |
| FunctionRewriterCallback fn_callback(&replacements); |
| match_finder.addMatcher(memberCallExpr(base_matcher, is_unsafe_return), |
| &fn_callback); |
| |
| // Rewrite logging / gtest expressions that result in an implicit conversion. |
| // Luckily, the matchers don't need to handle the case where one of the macro |
| // arguments is NULL, such as: |
| // CHECK_EQ(my_scoped_refptr, NULL) |
| // because it simply doesn't compile--since NULL is actually of integral type, |
| // this doesn't trigger scoped_refptr<T>'s implicit conversion. Since there is |
| // no comparison overload for scoped_refptr<T> and int, this fails to compile. |
| MacroRewriterCallback macro_callback(&replacements); |
| // CHECK_EQ/CHECK_NE helpers. |
| match_finder.addMatcher( |
| callExpr(callee(is_logging_helper), |
| argumentCountIs(3), |
| hasAnyArgument(id("expr", expr(hasType(is_scoped_refptr)))), |
| hasAnyArgument(hasType(pointerType())), |
| hasArgument(2, stringLiteral())), |
| ¯o_callback); |
| // ASSERT_EQ/ASSERT_NE/EXPECT_EQ/EXPECT_EQ, which use the same underlying |
| // helper functions. Even though gtest has special handling for pointer to |
| // NULL comparisons, it doesn't trigger in this case, so no special handling |
| // is needed for the replacements. |
| match_finder.addMatcher( |
| callExpr(callee(is_gtest_helper), |
| argumentCountIs(4), |
| hasArgument(0, stringLiteral()), |
| hasArgument(1, stringLiteral()), |
| hasAnyArgument(id("expr", expr(hasType(is_scoped_refptr)))), |
| hasAnyArgument(hasType(pointerType()))), |
| ¯o_callback); |
| // ASSERT_TRUE/EXPECT_TRUE helpers. Note that this matcher doesn't need to |
| // handle ASSERT_FALSE/EXPECT_FALSE, because it gets coerced to bool before |
| // being passed as an argument to AssertionResult's constructor. As a result, |
| // GetRewriterCallback handles this case properly since the conversion isn't |
| // hidden inside AssertionResult, and the generated replacement properly |
| // rewrites the macro argument. |
| // However, the tool does need to handle the _TRUE counterparts, since the |
| // conversion occurs inside the constructor in those cases. |
| match_finder.addMatcher( |
| constructExpr( |
| argumentCountIs(2), |
| hasArgument(0, id("expr", expr(hasType(is_scoped_refptr)))), |
| hasDeclaration(is_gtest_assertion_result_ctor)), |
| ¯o_callback); |
| |
| std::unique_ptr<clang::tooling::FrontendActionFactory> factory = |
| clang::tooling::newFrontendActionFactory(&match_finder); |
| int result = tool.run(factory.get()); |
| if (result != 0) |
| return result; |
| |
| // Serialization format is documented in tools/clang/scripts/run_tool.py |
| llvm::outs() << "==== BEGIN EDITS ====\n"; |
| 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; |
| } |