1 files changed, 110 insertions, 0 deletions
diff --git a/clang-tools-extra/clang-tidy/misc/InefficientAlgorithmCheck.cpp b/clang-tools-extra/clang-tidy/misc/InefficientAlgorithmCheck.cpp
new file mode 100644
index 00000000000..763d3765e0b
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/misc/InefficientAlgorithmCheck.cpp
@@ -0,0 +1,110 @@
+//===--- InefficientAlgorithmCheck.cpp - clang-tidy------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "InefficientAlgorithmCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+
+void InefficientAlgorithmCheck::registerMatchers(MatchFinder *Finder) {
+  const std::string Algorithms =
+      "std::(find|count|equal_range|lower_blound|upper_bound)";
+  const auto ContainerMatcher = classTemplateSpecializationDecl(
+      matchesName("std::(unordered_)?(multi)?(set|map)"));
+  const auto Matcher =
+      callExpr(
+          callee(functionDecl(matchesName(Algorithms))),
+          hasArgument(
+              0, constructExpr(has(memberCallExpr(
+                     callee(methodDecl(hasName("begin"))),
+                     on(declRefExpr(
+                            hasDeclaration(decl().bind("IneffContObj")),
+                            anyOf(hasType(ContainerMatcher.bind("IneffCont")),
+                                  hasType(pointsTo(
+                                      ContainerMatcher.bind("IneffContPtr")))))
+                            .bind("IneffContExpr")))))),
+          hasArgument(1, constructExpr(has(memberCallExpr(
+                             callee(methodDecl(hasName("end"))),
+                             on(declRefExpr(hasDeclaration(
+                                 equalsBoundNode("IneffContObj")))))))),
+          hasArgument(2, expr().bind("AlgParam")),
+          unless(isInTemplateInstantiation())).bind("IneffAlg");
+
+  Finder->addMatcher(Matcher, this);
+}
+
+void InefficientAlgorithmCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *AlgCall = Result.Nodes.getNodeAs<CallExpr>("IneffAlg");
+  const auto *IneffCont =
+      Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>("IneffCont");
+  bool PtrToContainer = false;
+  if (!IneffCont) {
+    IneffCont =
+        Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>("IneffContPtr");
+    PtrToContainer = true;
+  }
+  const llvm::StringRef IneffContName = IneffCont->getName();
+  const bool Unordered =
+      IneffContName.find("unordered") != llvm::StringRef::npos;
+
+  // Check if the comparison type for the algorithm and the container matches.
+  if (AlgCall->getNumArgs() == 4 && !Unordered) {
+    const Expr *Arg = AlgCall->getArg(3);
+    const QualType AlgCmp =
+        Arg->getType().getUnqualifiedType().getCanonicalType();
+    const unsigned CmpPosition =
+        (IneffContName.find("map") == llvm::StringRef::npos) ? 1 : 2;
+    const QualType ContainerCmp = IneffCont->getTemplateArgs()[CmpPosition]
+                                      .getAsType()
+                                      .getUnqualifiedType()
+                                      .getCanonicalType();
+    if (AlgCmp != ContainerCmp) {
+      diag(Arg->getLocStart(),
+           "different comparers used in the algorithm and the container");
+      return;
+    }
+  }
+
+  const auto *AlgDecl = AlgCall->getDirectCallee();
+  if (!AlgDecl)
+    return;
+
+  if (Unordered && AlgDecl->getName().find("bound") != llvm::StringRef::npos)
+    return;
+
+  const auto *AlgParam = Result.Nodes.getNodeAs<Expr>("AlgParam");
+  const auto *IneffContExpr = Result.Nodes.getNodeAs<Expr>("IneffContExpr");
+  FixItHint Hint;
+
+  if (!AlgCall->getLocStart().isMacroID()) {
+    std::string ReplacementText =
+        (llvm::Twine(Lexer::getSourceText(
+             CharSourceRange::getTokenRange(IneffContExpr->getSourceRange()),
+             *Result.SourceManager, Result.Context->getLangOpts())) +
+         (PtrToContainer ? "->" : ".") + AlgDecl->getName() + "(" +
+         Lexer::getSourceText(
+             CharSourceRange::getTokenRange(AlgParam->getSourceRange()),
+             *Result.SourceManager, Result.Context->getLangOpts()) +
+         ")").str();
+    Hint = FixItHint::CreateReplacement(AlgCall->getSourceRange(),
+                                        ReplacementText);
+  }
+
+  diag(AlgCall->getLocStart(),
+       "this STL algorithm call should be replaced with a container method")
+      << Hint;
+}
+
+} // namespace tidy
+} // namespace clang