[clang-tools-extra] r213058 - [clang-tidy] Add a checker that removes deducible arguments from std::make_pair

Benjamin Kramer benny.kra at googlemail.com
Tue Jul 15 02:50:32 PDT 2014


Author: d0k
Date: Tue Jul 15 04:50:32 2014
New Revision: 213058

URL: http://llvm.org/viewvc/llvm-project?rev=213058&view=rev
Log:
[clang-tidy] Add a checker that removes deducible arguments from std::make_pair

Those may be incompatible with C++11 and are unnecessary. We suggest
removing the template arguments when they match the types of the make_pair
arguments or replace it with std::pair and explicit template arguments when
not.

Differential Revision: http://reviews.llvm.org/D4497

Added:
    clang-tools-extra/trunk/clang-tidy/google/ExplicitMakePairCheck.cpp
    clang-tools-extra/trunk/clang-tidy/google/ExplicitMakePairCheck.h
    clang-tools-extra/trunk/test/clang-tidy/google-explicit-make-pair.cpp
Modified:
    clang-tools-extra/trunk/clang-tidy/google/CMakeLists.txt
    clang-tools-extra/trunk/clang-tidy/google/GoogleTidyModule.cpp

Modified: clang-tools-extra/trunk/clang-tidy/google/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/google/CMakeLists.txt?rev=213058&r1=213057&r2=213058&view=diff
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/google/CMakeLists.txt (original)
+++ clang-tools-extra/trunk/clang-tidy/google/CMakeLists.txt Tue Jul 15 04:50:32 2014
@@ -3,6 +3,7 @@ set(LLVM_LINK_COMPONENTS support)
 add_clang_library(clangTidyGoogleModule
   AvoidCStyleCastsCheck.cpp
   ExplicitConstructorCheck.cpp
+  ExplicitMakePairCheck.cpp
   GoogleTidyModule.cpp
 
   LINK_LIBS

Added: clang-tools-extra/trunk/clang-tidy/google/ExplicitMakePairCheck.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/google/ExplicitMakePairCheck.cpp?rev=213058&view=auto
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/google/ExplicitMakePairCheck.cpp (added)
+++ clang-tools-extra/trunk/clang-tidy/google/ExplicitMakePairCheck.cpp Tue Jul 15 04:50:32 2014
@@ -0,0 +1,71 @@
+//===--- ExplicitMakePairCheck.cpp - clang-tidy -----------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ExplicitMakePairCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/AST/ASTContext.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+
+namespace ast_matchers {
+AST_MATCHER(DeclRefExpr, hasExplicitTemplateArgs) {
+  return Node.hasExplicitTemplateArgs();
+}
+} // namespace ast_matchers
+
+namespace tidy {
+namespace build {
+
+void
+ExplicitMakePairCheck::registerMatchers(ast_matchers::MatchFinder *Finder) {
+  // Look for std::make_pair with explicit template args. Ignore calls in
+  // templates.
+  Finder->addMatcher(
+      callExpr(unless(hasAncestor(decl(anyOf(
+                   recordDecl(ast_matchers::isTemplateInstantiation()),
+                   functionDecl(ast_matchers::isTemplateInstantiation()))))),
+               has(declRefExpr(hasExplicitTemplateArgs()).bind("declref")),
+               callee(functionDecl(hasName("::std::make_pair")))).bind("call"),
+      this);
+}
+
+void ExplicitMakePairCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *Call = Result.Nodes.getNodeAs<CallExpr>("call");
+  const auto *DeclRef = Result.Nodes.getNodeAs<DeclRefExpr>("declref");
+
+  // Sanity check: The use might have overriden ::std::make_pair.
+  if (Call->getNumArgs() != 2)
+    return;
+
+  const Expr *Arg0 = Call->getArg(0)->IgnoreParenImpCasts();
+  const Expr *Arg1 = Call->getArg(1)->IgnoreParenImpCasts();
+
+  // If types don't match, we suggest replacing with std::pair and explicit
+  // template arguments. Otherwise just remove the template arguments from
+  // make_pair.
+  if (Arg0->getType() != Call->getArg(0)->getType() ||
+      Arg1->getType() != Call->getArg(1)->getType()) {
+    diag(Call->getLocStart(), "for C++11-compatibility, use pair directly")
+        << FixItHint::CreateReplacement(
+            SourceRange(DeclRef->getLocStart(), DeclRef->getLAngleLoc()),
+            "std::pair<");
+  } else {
+    diag(Call->getLocStart(),
+         "for C++11-compatibility, omit template arguments from make_pair")
+        << FixItHint::CreateRemoval(
+            SourceRange(DeclRef->getLAngleLoc(), DeclRef->getRAngleLoc()));
+  }
+}
+
+} // namespace build
+} // namespace tidy
+} // namespace clang

Added: clang-tools-extra/trunk/clang-tidy/google/ExplicitMakePairCheck.h
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/google/ExplicitMakePairCheck.h?rev=213058&view=auto
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/google/ExplicitMakePairCheck.h (added)
+++ clang-tools-extra/trunk/clang-tidy/google/ExplicitMakePairCheck.h Tue Jul 15 04:50:32 2014
@@ -0,0 +1,35 @@
+//===--- ExplicitMakePairCheck.h - clang-tidy -------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_EXPLICIT_MAKE_PAIR_CHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_EXPLICIT_MAKE_PAIR_CHECK_H
+
+#include "../ClangTidy.h"
+
+namespace clang {
+namespace tidy {
+namespace build {
+
+/// \brief Check that make_pair's template arguments are deduced.
+///
+/// G++ 4.6 in C++11 mode fails badly if make_pair's template arguments are
+/// specified explicitly, and such use isn't intended in any case.
+///
+/// Corresponding cpplint.py check name: 'build/explicit_make_pair'.
+class ExplicitMakePairCheck : public ClangTidyCheck {
+public:
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace build
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_GOOGLE_EXPLICIT_MAKE_PAIR_CHECK_H

Modified: clang-tools-extra/trunk/clang-tidy/google/GoogleTidyModule.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/google/GoogleTidyModule.cpp?rev=213058&r1=213057&r2=213058&view=diff
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/google/GoogleTidyModule.cpp (original)
+++ clang-tools-extra/trunk/clang-tidy/google/GoogleTidyModule.cpp Tue Jul 15 04:50:32 2014
@@ -12,6 +12,7 @@
 #include "../ClangTidyModuleRegistry.h"
 #include "AvoidCStyleCastsCheck.h"
 #include "ExplicitConstructorCheck.h"
+#include "ExplicitMakePairCheck.h"
 
 using namespace clang::ast_matchers;
 
@@ -22,6 +23,9 @@ class GoogleModule : public ClangTidyMod
 public:
   void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override {
     CheckFactories.addCheckFactory(
+        "google-build-explicit-make-pair",
+        new ClangTidyCheckFactory<build::ExplicitMakePairCheck>());
+    CheckFactories.addCheckFactory(
         "google-explicit-constructor",
         new ClangTidyCheckFactory<ExplicitConstructorCheck>());
     CheckFactories.addCheckFactory(

Added: clang-tools-extra/trunk/test/clang-tidy/google-explicit-make-pair.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/test/clang-tidy/google-explicit-make-pair.cpp?rev=213058&view=auto
==============================================================================
--- clang-tools-extra/trunk/test/clang-tidy/google-explicit-make-pair.cpp (added)
+++ clang-tools-extra/trunk/test/clang-tidy/google-explicit-make-pair.cpp Tue Jul 15 04:50:32 2014
@@ -0,0 +1,44 @@
+// RUN: $(dirname %s)/check_clang_tidy_fix.sh %s google-build-explicit-make-pair %t
+// REQUIRES: shell
+
+namespace std {
+template <class T1, class T2>
+struct pair {
+  pair(T1 x, T2 y) {}
+};
+
+template <class T1, class T2>
+pair<T1, T2> make_pair(T1 x, T2 y) {
+  return pair<T1, T2>(x, y);
+}
+}
+
+template <typename T>
+void templ(T a, T b) {
+  std::make_pair<T, unsigned>(a, b);
+}
+
+void test(int i) {
+  std::make_pair<int, int>(i, i);
+// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: for C++11-compatibility, omit template arguments from make_pair
+// CHECK-FIXES: std::make_pair(i, i)
+
+  std::make_pair<unsigned, int>(i, i);
+// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: for C++11-compatibility, use pair directly
+// CHECK-FIXES: std::pair<unsigned, int>(i, i)
+
+  std::make_pair<int, unsigned>(i, i);
+// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: for C++11-compatibility, use pair directly
+// CHECK-FIXES: std::pair<int, unsigned>(i, i)
+
+#define M std::make_pair<int, unsigned>(i, i);
+M
+// CHECK-MESSAGES: :[[@LINE-1]]:1: warning: for C++11-compatibility, use pair directly
+// Can't fix in macros.
+// CHECK-FIXES: #define M std::make_pair<int, unsigned>(i, i);
+// CHECK-FIXES-NEXT: M
+
+  templ(i, i);
+
+  std::make_pair(i, 1); // no-warning
+}





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