[clang-tools-extra] [clang-tidy] add check to suggest replacement of nested std::min or std::max with initializer lists (PR #85572)

[Julian Schmidt via cfe-commits]

================
@@ -0,0 +1,199 @@
+//===--- MinMaxUseInitializerListCheck.cpp - clang-tidy -------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "MinMaxUseInitializerListCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Lex/Lexer.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::modernize {
+
+MinMaxUseInitializerListCheck::MinMaxUseInitializerListCheck(
+    StringRef Name, ClangTidyContext *Context)
+    : ClangTidyCheck(Name, Context),
+      Inserter(Options.getLocalOrGlobal("IncludeStyle",
+                                        utils::IncludeSorter::IS_LLVM),
+               areDiagsSelfContained()) {}
+
+void MinMaxUseInitializerListCheck::storeOptions(
+    ClangTidyOptions::OptionMap &Opts) {
+  Options.store(Opts, "IncludeStyle", Inserter.getStyle());
+}
+
+void MinMaxUseInitializerListCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(
+      callExpr(
+          callee(functionDecl(hasName("::std::max"))),
+          anyOf(hasArgument(
+                    0, callExpr(callee(functionDecl(hasName("::std::max"))))),
+                hasArgument(
+                    1, callExpr(callee(functionDecl(hasName("::std::max")))))),
+          unless(
+              hasParent(callExpr(callee(functionDecl(hasName("::std::max")))))))
+          .bind("topCall"),
+      this);
+
+  Finder->addMatcher(
+      callExpr(
+          callee(functionDecl(hasName("::std::min"))),
+          anyOf(hasArgument(
+                    0, callExpr(callee(functionDecl(hasName("::std::min"))))),
+                hasArgument(
+                    1, callExpr(callee(functionDecl(hasName("::std::min")))))),
+          unless(
+              hasParent(callExpr(callee(functionDecl(hasName("::std::min")))))))
+          .bind("topCall"),
+      this);
+}
+
+void MinMaxUseInitializerListCheck::registerPPCallbacks(
+    const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
+  Inserter.registerPreprocessor(PP);
+}
+
+void MinMaxUseInitializerListCheck::check(
+    const MatchFinder::MatchResult &Match) {
+  const CallExpr *TopCall = Match.Nodes.getNodeAs<CallExpr>("topCall");
+  MinMaxUseInitializerListCheck::FindArgsResult Result =
+      findArgs(Match, TopCall);
+
+  if (!Result.First || !Result.Last || Result.Args.size() <= 2) {
+    return;
+  }
+
+  std::string ReplacementText = generateReplacement(Match, TopCall, Result);
+
+  diag(TopCall->getBeginLoc(),
+       "do not use nested std::%0 calls, use %1 instead")
+      << TopCall->getDirectCallee()->getName() << ReplacementText
+      << FixItHint::CreateReplacement(
+             CharSourceRange::getTokenRange(TopCall->getBeginLoc(),
+                                            TopCall->getEndLoc()),
+             ReplacementText)
+      << Inserter.createMainFileIncludeInsertion("<algorithm>");
+}
+
+MinMaxUseInitializerListCheck::FindArgsResult
+MinMaxUseInitializerListCheck::findArgs(const MatchFinder::MatchResult &Match,
+                                        const CallExpr *Call) {
+  FindArgsResult Result;
+  Result.First = nullptr;
+  Result.Last = nullptr;
+  Result.Compare = nullptr;
+
+  if (Call->getNumArgs() > 2) {
+    auto ArgIterator = Call->arguments().begin();
+    std::advance(ArgIterator, 2);
+    Result.Compare = *ArgIterator;
+  }
+
+  for (const Expr *Arg : Call->arguments()) {
+    if (!Result.First)
+      Result.First = Arg;
+
+    const CallExpr *InnerCall = dyn_cast<CallExpr>(Arg);
+    if (InnerCall && InnerCall->getDirectCallee() &&
+        InnerCall->getDirectCallee()->getNameAsString() ==
+            Call->getDirectCallee()->getNameAsString()) {
+      FindArgsResult InnerResult = findArgs(Match, InnerCall);
+
+      bool processInnerResult = false;
+
+      if (!Result.Compare && !InnerResult.Compare)
+        processInnerResult = true;
+      else if (Result.Compare && InnerResult.Compare &&
+               Lexer::getSourceText(CharSourceRange::getTokenRange(
+                                        Result.Compare->getSourceRange()),
+                                    *Match.SourceManager,
+                                    Match.Context->getLangOpts()) ==
+                   Lexer::getSourceText(
+                       CharSourceRange::getTokenRange(
+                           InnerResult.Compare->getSourceRange()),
+                       *Match.SourceManager, Match.Context->getLangOpts()))
+        processInnerResult = true;
+
+      if (processInnerResult) {
+        Result.Args.insert(Result.Args.end(), InnerResult.Args.begin(),
+                           InnerResult.Args.end());
+        continue;
+      }
+    }
+
+    if (Arg == Result.Compare)
+      continue;
+
+    Result.Args.push_back(Arg);
+    Result.Last = Arg;
+  }
+
+  return Result;
+}
+
+std::string MinMaxUseInitializerListCheck::generateReplacement(
+    const MatchFinder::MatchResult &Match, const CallExpr *TopCall,
+    const FindArgsResult Result) {
----------------
5chmidti wrote:

Pass `Result` by reference, it contains a vector

https://github.com/llvm/llvm-project/pull/85572