diff options
Diffstat (limited to 'clang/lib/CodeGen/CGExprCXX.cpp')
| -rw-r--r-- | clang/lib/CodeGen/CGExprCXX.cpp | 96 |
1 files changed, 1 insertions, 95 deletions
diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp index 43318a73d56..53140218a01 100644 --- a/clang/lib/CodeGen/CGExprCXX.cpp +++ b/clang/lib/CodeGen/CGExprCXX.cpp @@ -62,99 +62,6 @@ RValue CodeGenFunction::EmitCXXMemberCall(const CXXMethodDecl *MD, Callee, ReturnValue, Args, MD); } -// FIXME: Ideally Expr::IgnoreParenNoopCasts should do this, but it doesn't do -// quite what we want. -static const Expr *skipNoOpCastsAndParens(const Expr *E) { - while (true) { - if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) { - E = PE->getSubExpr(); - continue; - } - - if (const CastExpr *CE = dyn_cast<CastExpr>(E)) { - if (CE->getCastKind() == CK_NoOp) { - E = CE->getSubExpr(); - continue; - } - } - if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { - if (UO->getOpcode() == UO_Extension) { - E = UO->getSubExpr(); - continue; - } - } - return E; - } -} - -/// canDevirtualizeMemberFunctionCalls - Checks whether virtual calls on given -/// expr can be devirtualized. -static bool canDevirtualizeMemberFunctionCalls(ASTContext &Context, - const Expr *Base, - const CXXMethodDecl *MD) { - - // When building with -fapple-kext, all calls must go through the vtable since - // the kernel linker can do runtime patching of vtables. - if (Context.getLangOpts().AppleKext) - return false; - - // If the most derived class is marked final, we know that no subclass can - // override this member function and so we can devirtualize it. For example: - // - // struct A { virtual void f(); } - // struct B final : A { }; - // - // void f(B *b) { - // b->f(); - // } - // - const CXXRecordDecl *MostDerivedClassDecl = Base->getBestDynamicClassType(); - if (MostDerivedClassDecl->hasAttr<FinalAttr>()) - return true; - - // If the member function is marked 'final', we know that it can't be - // overridden and can therefore devirtualize it. - if (MD->hasAttr<FinalAttr>()) - return true; - - // Similarly, if the class itself is marked 'final' it can't be overridden - // and we can therefore devirtualize the member function call. - if (MD->getParent()->hasAttr<FinalAttr>()) - return true; - - Base = skipNoOpCastsAndParens(Base); - if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base)) { - if (const VarDecl *VD = dyn_cast<VarDecl>(DRE->getDecl())) { - // This is a record decl. We know the type and can devirtualize it. - return VD->getType()->isRecordType(); - } - - return false; - } - - // We can devirtualize calls on an object accessed by a class member access - // expression, since by C++11 [basic.life]p6 we know that it can't refer to - // a derived class object constructed in the same location. - if (const MemberExpr *ME = dyn_cast<MemberExpr>(Base)) - if (const ValueDecl *VD = dyn_cast<ValueDecl>(ME->getMemberDecl())) - return VD->getType()->isRecordType(); - - // We can always devirtualize calls on temporary object expressions. - if (isa<CXXConstructExpr>(Base)) - return true; - - // And calls on bound temporaries. - if (isa<CXXBindTemporaryExpr>(Base)) - return true; - - // Check if this is a call expr that returns a record type. - if (const CallExpr *CE = dyn_cast<CallExpr>(Base)) - return CE->getCallReturnType()->isRecordType(); - - // We can't devirtualize the call. - return false; -} - static CXXRecordDecl *getCXXRecord(const Expr *E) { QualType T = E->getType(); if (const PointerType *PTy = T->getAs<PointerType>()) @@ -187,8 +94,7 @@ RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE, bool CanUseVirtualCall = MD->isVirtual() && !ME->hasQualifier(); const CXXMethodDecl *DevirtualizedMethod = NULL; - if (CanUseVirtualCall && - canDevirtualizeMemberFunctionCalls(getContext(), Base, MD)) { + if (CanUseVirtualCall && CanDevirtualizeMemberFunctionCall(Base, MD)) { const CXXRecordDecl *BestDynamicDecl = Base->getBestDynamicClassType(); DevirtualizedMethod = MD->getCorrespondingMethodInClass(BestDynamicDecl); assert(DevirtualizedMethod); |

