================ @@ -0,0 +1,125 @@ +//===--- 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/AST/RecursiveASTVisitor.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) { + // 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; + + class SubspanVisitor : public RecursiveASTVisitor<SubspanVisitor> { + public: + SubspanVisitor(const ASTContext &Context) : Context(Context) {} + + TraversalKind getTraversalKind() const { + return TK_IgnoreUnlessSpelledInSource; + } + + bool VisitIntegerLiteral(IntegerLiteral *IL) { + if (IL->getValue() == 0) + IsZeroOffset = true; + return true; + } + + bool VisitBinaryOperator(BinaryOperator *BO) { + if (BO->getOpcode() == BO_Sub) { + if (const auto *SizeCall = dyn_cast<CXXMemberCallExpr>(BO->getLHS())) { + if (SizeCall->getMethodDecl()->getName() == "size") { + IsSizeMinusN = true; + SizeMinusArg = BO->getRHS(); + } + } + } + return true; + } + + bool IsZeroOffset = false; + bool IsSizeMinusN = false; + const Expr *SizeMinusArg = nullptr; + + private: + const ASTContext &Context; + }; + + SubspanVisitor Visitor(Context); + Visitor.TraverseStmt(const_cast<Expr *>(Offset->IgnoreImpCasts())); + + // Build replacement text + std::string Replacement; + if (Visitor.IsZeroOffset && Count) { + // subspan(0, count) -> first(count) + const StringRef CountStr = Lexer::getSourceText( + CharSourceRange::getTokenRange(Count->getSourceRange()), + Context.getSourceManager(), Context.getLangOpts()); + const auto *Base = + cast<CXXMemberCallExpr>(Call)->getImplicitObjectArgument(); + const StringRef BaseStr = Lexer::getSourceText( + CharSourceRange::getTokenRange(Base->getSourceRange()), + Context.getSourceManager(), Context.getLangOpts()); + Replacement = BaseStr.str() + ".first(" + CountStr.str() + ")"; + } else if (Visitor.IsSizeMinusN && Visitor.SizeMinusArg) { + // subspan(size() - n) -> last(n) + const StringRef ArgStr = Lexer::getSourceText( + CharSourceRange::getTokenRange(Visitor.SizeMinusArg->getSourceRange()), + Context.getSourceManager(), Context.getLangOpts()); + const auto *Base = + cast<CXXMemberCallExpr>(Call)->getImplicitObjectArgument(); ---------------- 5chmidti wrote:
Same as above 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
