forked from OSchip/llvm-project
102 lines
3.2 KiB
C++
102 lines
3.2 KiB
C++
//===------------- Aliasing.cpp - clang-tidy ------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "Aliasing.h"
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#include "clang/AST/Expr.h"
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#include "clang/AST/ExprCXX.h"
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namespace clang {
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namespace tidy {
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namespace utils {
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/// Return whether \p S is a reference to the declaration of \p Var.
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static bool isAccessForVar(const Stmt *S, const VarDecl *Var) {
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if (const auto *DRE = dyn_cast<DeclRefExpr>(S))
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return DRE->getDecl() == Var;
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return false;
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}
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static bool capturesByRef(const CXXRecordDecl *RD, const VarDecl *Var) {
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return llvm::any_of(RD->captures(), [Var](const LambdaCapture &C) {
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return C.capturesVariable() && C.getCaptureKind() == LCK_ByRef &&
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C.getCapturedVar() == Var;
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});
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}
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/// Return whether \p Var has a pointer or reference in \p S.
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static bool isPtrOrReferenceForVar(const Stmt *S, const VarDecl *Var) {
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// Treat block capture by reference as a form of taking a reference.
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if (Var->isEscapingByref())
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return true;
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if (const auto *DS = dyn_cast<DeclStmt>(S)) {
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for (const Decl *D : DS->getDeclGroup()) {
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if (const auto *LeftVar = dyn_cast<VarDecl>(D)) {
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if (LeftVar->hasInit() && LeftVar->getType()->isReferenceType()) {
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return isAccessForVar(LeftVar->getInit(), Var);
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}
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}
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}
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} else if (const auto *UnOp = dyn_cast<UnaryOperator>(S)) {
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if (UnOp->getOpcode() == UO_AddrOf)
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return isAccessForVar(UnOp->getSubExpr(), Var);
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} else if (const auto *LE = dyn_cast<LambdaExpr>(S)) {
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// Treat lambda capture by reference as a form of taking a reference.
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return capturesByRef(LE->getLambdaClass(), Var);
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} else if (const auto *ILE = dyn_cast<InitListExpr>(S)) {
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return llvm::any_of(ILE->inits(), [Var](const Expr *ChildE) {
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// If the child expression is a reference to Var, this means that it's
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// used as an initializer of a reference-typed field. Otherwise
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// it would have been surrounded with an implicit lvalue-to-rvalue cast.
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return isAccessForVar(ChildE, Var);
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});
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}
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return false;
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}
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/// Return whether \p Var has a pointer or reference in \p S.
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static bool hasPtrOrReferenceInStmt(const Stmt *S, const VarDecl *Var) {
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if (isPtrOrReferenceForVar(S, Var))
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return true;
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for (const Stmt *Child : S->children()) {
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if (!Child)
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continue;
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if (hasPtrOrReferenceInStmt(Child, Var))
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return true;
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}
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return false;
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}
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static bool refersToEnclosingLambdaCaptureByRef(const Decl *Func,
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const VarDecl *Var) {
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const auto *MD = dyn_cast<CXXMethodDecl>(Func);
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if (!MD)
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return false;
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const CXXRecordDecl *RD = MD->getParent();
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if (!RD->isLambda())
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return false;
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return capturesByRef(RD, Var);
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}
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bool hasPtrOrReferenceInFunc(const Decl *Func, const VarDecl *Var) {
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return hasPtrOrReferenceInStmt(Func->getBody(), Var) ||
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refersToEnclosingLambdaCaptureByRef(Func, Var);
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}
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} // namespace utils
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} // namespace tidy
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} // namespace clang
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