CodeGen: Unify two implementations of canDevirtualizeMemberFunctionCall.
They were mostly copy&paste of each other, move it to CodeGenFunction. Of course
the two implementations have diverged over time; the one in CGExprCXX seems to
be the more modern one so I picked that one and moved it to CGClass which feels
like a better home for it. No intended functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@189203 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExprCXX.cpp b/lib/CodeGen/CGExprCXX.cpp
index 43318a7..5314021 100644
--- a/lib/CodeGen/CGExprCXX.cpp
+++ b/lib/CodeGen/CGExprCXX.cpp
@@ -62,99 +62,6 @@
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 @@
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);