98 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "Aliasing.h"10 11#include "clang/AST/Expr.h"12#include "clang/AST/ExprCXX.h"13 14namespace clang::tidy::utils {15 16/// Return whether \p S is a reference to the declaration of \p Var.17static bool isAccessForVar(const Stmt *S, const ValueDecl *Var) {18 if (const auto *DRE = dyn_cast<DeclRefExpr>(S))19 return DRE->getDecl() == Var;20 21 return false;22}23 24static bool capturesByRef(const CXXRecordDecl *RD, const ValueDecl *Var) {25 return llvm::any_of(RD->captures(), [Var](const LambdaCapture &C) {26 return C.capturesVariable() && C.getCaptureKind() == LCK_ByRef &&27 C.getCapturedVar() == Var;28 });29}30 31/// Return whether \p Var has a pointer or reference in \p S.32static bool isPtrOrReferenceForVar(const Stmt *S, const ValueDecl *Var) {33 // Treat block capture by reference as a form of taking a reference.34 if (const auto *VD = dyn_cast<VarDecl>(Var); VD && VD->isEscapingByref())35 return true;36 37 if (const auto *DS = dyn_cast<DeclStmt>(S)) {38 for (const Decl *D : DS->getDeclGroup()) {39 if (const auto *LeftVar = dyn_cast<VarDecl>(D)) {40 if (LeftVar->hasInit() && LeftVar->getType()->isReferenceType()) {41 return isAccessForVar(LeftVar->getInit(), Var);42 }43 }44 }45 } else if (const auto *UnOp = dyn_cast<UnaryOperator>(S)) {46 if (UnOp->getOpcode() == UO_AddrOf)47 return isAccessForVar(UnOp->getSubExpr(), Var);48 } else if (const auto *LE = dyn_cast<LambdaExpr>(S)) {49 // Treat lambda capture by reference as a form of taking a reference.50 return capturesByRef(LE->getLambdaClass(), Var);51 } else if (const auto *ILE = dyn_cast<InitListExpr>(S)) {52 return llvm::any_of(ILE->inits(), [Var](const Expr *ChildE) {53 // If the child expression is a reference to Var, this means that it's54 // used as an initializer of a reference-typed field. Otherwise55 // it would have been surrounded with an implicit lvalue-to-rvalue cast.56 return isAccessForVar(ChildE, Var);57 });58 }59 60 return false;61}62 63/// Return whether \p Var has a pointer or reference in \p S.64static bool hasPtrOrReferenceInStmt(const Stmt *S, const ValueDecl *Var) {65 if (isPtrOrReferenceForVar(S, Var))66 return true;67 68 for (const Stmt *Child : S->children()) {69 if (!Child)70 continue;71 72 if (hasPtrOrReferenceInStmt(Child, Var))73 return true;74 }75 76 return false;77}78 79static bool refersToEnclosingLambdaCaptureByRef(const Decl *Func,80 const ValueDecl *Var) {81 const auto *MD = dyn_cast<CXXMethodDecl>(Func);82 if (!MD)83 return false;84 85 const CXXRecordDecl *RD = MD->getParent();86 if (!RD->isLambda())87 return false;88 89 return capturesByRef(RD, Var);90}91 92bool hasPtrOrReferenceInFunc(const Decl *Func, const ValueDecl *Var) {93 return hasPtrOrReferenceInStmt(Func->getBody(), Var) ||94 refersToEnclosingLambdaCaptureByRef(Func, Var);95}96 97} // namespace clang::tidy::utils98