================ @@ -0,0 +1,110 @@ +//===--- UseSpanFirstLastCheck.cpp - clang-tidy-----------------*- C++ -*-===// +// +// 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 "UseSpanFirstLastCheck.h" +#include "clang/AST/ASTContext.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" +#include "clang/ASTMatchers/ASTMatchers.h" +#include "clang/Lex/Lexer.h" + +using namespace clang::ast_matchers; + +namespace clang::tidy::readability { + +void UseSpanFirstLastCheck::registerMatchers(MatchFinder *Finder) { + if (!getLangOpts().CPlusPlus20) + return; + + // Match span::subspan calls + const auto HasSpanType = + hasType(hasUnqualifiedDesugaredType(recordType(hasDeclaration( + classTemplateSpecializationDecl(hasName("::std::span")))))); + + Finder->addMatcher(cxxMemberCallExpr(callee(memberExpr(hasDeclaration( + cxxMethodDecl(hasName("subspan"))))), + on(expr(HasSpanType))) + .bind("subspan"), + this); +} + +void UseSpanFirstLastCheck::check(const MatchFinder::MatchResult &Result) { + const auto *Call = Result.Nodes.getNodeAs<CXXMemberCallExpr>("subspan"); + if (!Call) + return; + + handleSubspanCall(Result, Call); +} + +void UseSpanFirstLastCheck::handleSubspanCall( + const MatchFinder::MatchResult &Result, const CXXMemberCallExpr *Call) { + unsigned NumArgs = Call->getNumArgs(); + if (NumArgs == 0 || NumArgs > 2) + return; + + const Expr *Offset = Call->getArg(0); + const Expr *Count = NumArgs > 1 ? Call->getArg(1) : nullptr; + auto &Context = *Result.Context; + + // Check if this is subspan(0, n) -> first(n) + bool IsZeroOffset = false; + const Expr *OffsetE = Offset->IgnoreImpCasts(); + if (const auto *IL = dyn_cast<IntegerLiteral>(OffsetE)) { + IsZeroOffset = IL->getValue() == 0; + } + + // Check if this is subspan(size() - n) -> last(n) + bool IsSizeMinusN = false; + const Expr *SizeMinusArg = nullptr; + if (const auto *BO = dyn_cast<BinaryOperator>(OffsetE)) { + if (BO->getOpcode() == BO_Sub) { + if (const auto *SizeCall = dyn_cast<CXXMemberCallExpr>(BO->getLHS())) { + if (SizeCall->getMethodDecl()->getName() == "size") { + IsSizeMinusN = true; + SizeMinusArg = BO->getRHS(); + } + } + } + } + + // Build replacement text + std::string Replacement; + if (IsZeroOffset && Count) { + // subspan(0, count) -> first(count) + auto CountStr = Lexer::getSourceText( + CharSourceRange::getTokenRange(Count->getSourceRange()), + Context.getSourceManager(), Context.getLangOpts()); + const auto *Base = + cast<CXXMemberCallExpr>(Call)->getImplicitObjectArgument(); + auto BaseStr = Lexer::getSourceText( + CharSourceRange::getTokenRange(Base->getSourceRange()), + Context.getSourceManager(), Context.getLangOpts()); + Replacement = BaseStr.str() + ".first(" + CountStr.str() + ")"; + } else if (IsSizeMinusN && SizeMinusArg) { + // subspan(size() - n) -> last(n) + auto ArgStr = Lexer::getSourceText( ---------------- EugeneZelenko wrote:
Please use type. Same for `BaseStr`. https://github.com/llvm/llvm-project/pull/118074 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
