During codegen of a virtual call we would extract any casts in the expression
to see if we had an underlying final class or method, but we would then
use the cast type to do the call, resulting in a direct call to the wrong
method.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@159212 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/AST/DeclCXX.h b/include/clang/AST/DeclCXX.h
index 6fe71c8..8fde3ed 100644
--- a/include/clang/AST/DeclCXX.h
+++ b/include/clang/AST/DeclCXX.h
@@ -1630,7 +1630,20 @@
/// supplied by IR generation to either forward to the function call operator
/// or clone the function call operator.
bool isLambdaStaticInvoker() const;
-
+
+ /// \brief Find the method in RD that corresponds to this one.
+ ///
+ /// Find if RD or one of the classes it inherits from override this method.
+ /// If so, return it. RD is assumed to be a base class of the class defining
+ /// this method (or be the class itself).
+ CXXMethodDecl *
+ getCorrespondingMethodInClass(const CXXRecordDecl *RD);
+
+ const CXXMethodDecl *
+ getCorrespondingMethodInClass(const CXXRecordDecl *RD) const {
+ return const_cast<CXXMethodDecl*>(this)->getCorrespondingMethodInClass(RD);
+ }
+
// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classof(const CXXMethodDecl *D) { return true; }
diff --git a/include/clang/AST/Expr.h b/include/clang/AST/Expr.h
index cdf9a58..77684ee 100644
--- a/include/clang/AST/Expr.h
+++ b/include/clang/AST/Expr.h
@@ -665,6 +665,13 @@
static bool hasAnyTypeDependentArguments(llvm::ArrayRef<Expr *> Exprs);
+ /// \brief If we have class type (or pointer to class type), return the
+ /// class decl. Return NULL otherwise.
+ ///
+ /// If this expression is a cast, this method looks through it to find the
+ /// most derived decl that can be infered from the expression.
+ const CXXRecordDecl *getMostDerivedClassDeclForType() const;
+
static bool classof(const Stmt *T) {
return T->getStmtClass() >= firstExprConstant &&
T->getStmtClass() <= lastExprConstant;
diff --git a/lib/AST/DeclCXX.cpp b/lib/AST/DeclCXX.cpp
index 3d76e68..a8aabb6 100644
--- a/lib/AST/DeclCXX.cpp
+++ b/lib/AST/DeclCXX.cpp
@@ -1269,6 +1269,55 @@
void CXXMethodDecl::anchor() { }
+static bool recursivelyOverrides(const CXXMethodDecl *DerivedMD,
+ const CXXMethodDecl *BaseMD) {
+ for (CXXMethodDecl::method_iterator I = DerivedMD->begin_overridden_methods(),
+ E = DerivedMD->end_overridden_methods(); I != E; ++I) {
+ const CXXMethodDecl *MD = *I;
+ if (MD->getCanonicalDecl() == BaseMD->getCanonicalDecl())
+ return true;
+ if (recursivelyOverrides(MD, BaseMD))
+ return true;
+ }
+ return false;
+}
+
+CXXMethodDecl *
+CXXMethodDecl::getCorrespondingMethodInClass(const CXXRecordDecl *RD) {
+ if (this->getParent()->getCanonicalDecl() == RD->getCanonicalDecl())
+ return this;
+
+ // Lookup doesn't work for destructors, so handle them separately.
+ if (isa<CXXDestructorDecl>(this)) {
+ CXXMethodDecl *MD = RD->getDestructor();
+ if (recursivelyOverrides(MD, this))
+ return MD;
+ return NULL;
+ }
+
+ lookup_const_result Candidates = RD->lookup(getDeclName());
+ for (NamedDecl * const * I = Candidates.first; I != Candidates.second; ++I) {
+ CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(*I);
+ if (!MD)
+ continue;
+ if (recursivelyOverrides(MD, this))
+ return MD;
+ }
+
+ for (CXXRecordDecl::base_class_const_iterator I = RD->bases_begin(),
+ E = RD->bases_end(); I != E; ++I) {
+ const RecordType *RT = I->getType()->getAs<RecordType>();
+ if (!RT)
+ continue;
+ const CXXRecordDecl *Base = cast<CXXRecordDecl>(RT->getDecl());
+ CXXMethodDecl *T = this->getCorrespondingMethodInClass(Base);
+ if (T)
+ return T;
+ }
+
+ return NULL;
+}
+
CXXMethodDecl *
CXXMethodDecl::Create(ASTContext &C, CXXRecordDecl *RD,
SourceLocation StartLoc,
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 3de4b57..22d15be 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -33,6 +33,37 @@
#include <cstring>
using namespace clang;
+const CXXRecordDecl *Expr::getMostDerivedClassDeclForType() const {
+ const Expr *E = this;
+
+ while (true) {
+ E = E->IgnoreParens();
+ if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
+ if (CE->getCastKind() == CK_DerivedToBase ||
+ CE->getCastKind() == CK_UncheckedDerivedToBase ||
+ CE->getCastKind() == CK_NoOp) {
+ E = CE->getSubExpr();
+ continue;
+ }
+ }
+
+ break;
+ }
+
+ QualType DerivedType = E->getType();
+ if (DerivedType->isDependentType())
+ return NULL;
+ if (const PointerType *PTy = DerivedType->getAs<PointerType>())
+ DerivedType = PTy->getPointeeType();
+
+ const RecordType *Ty = DerivedType->castAs<RecordType>();
+ if (!Ty)
+ return NULL;
+
+ Decl *D = Ty->getDecl();
+ return cast<CXXRecordDecl>(D);
+}
+
/// isKnownToHaveBooleanValue - Return true if this is an integer expression
/// that is known to return 0 or 1. This happens for _Bool/bool expressions
/// but also int expressions which are produced by things like comparisons in
diff --git a/lib/CodeGen/CGExprCXX.cpp b/lib/CodeGen/CGExprCXX.cpp
index f1d0395..f35287d 100644
--- a/lib/CodeGen/CGExprCXX.cpp
+++ b/lib/CodeGen/CGExprCXX.cpp
@@ -56,30 +56,6 @@
Callee, ReturnValue, Args, MD);
}
-static const CXXRecordDecl *getMostDerivedClassDecl(const Expr *Base) {
- const Expr *E = Base;
-
- while (true) {
- E = E->IgnoreParens();
- if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
- if (CE->getCastKind() == CK_DerivedToBase ||
- CE->getCastKind() == CK_UncheckedDerivedToBase ||
- CE->getCastKind() == CK_NoOp) {
- E = CE->getSubExpr();
- continue;
- }
- }
-
- break;
- }
-
- QualType DerivedType = E->getType();
- if (const PointerType *PTy = DerivedType->getAs<PointerType>())
- DerivedType = PTy->getPointeeType();
-
- return cast<CXXRecordDecl>(DerivedType->castAs<RecordType>()->getDecl());
-}
-
// FIXME: Ideally Expr::IgnoreParenNoopCasts should do this, but it doesn't do
// quite what we want.
static const Expr *skipNoOpCastsAndParens(const Expr *E) {
@@ -126,7 +102,8 @@
// b->f();
// }
//
- const CXXRecordDecl *MostDerivedClassDecl = getMostDerivedClassDecl(Base);
+ const CXXRecordDecl *MostDerivedClassDecl =
+ Base->getMostDerivedClassDeclForType();
if (MostDerivedClassDecl->hasAttr<FinalAttr>())
return true;
@@ -247,10 +224,13 @@
//
// We also don't emit a virtual call if the base expression has a record type
// because then we know what the type is.
- bool UseVirtualCall;
- UseVirtualCall = MD->isVirtual() && !ME->hasQualifier()
- && !canDevirtualizeMemberFunctionCalls(getContext(),
- ME->getBase(), MD);
+ const Expr *Base = ME->getBase();
+ bool UseVirtualCall = MD->isVirtual() && !ME->hasQualifier()
+ && !canDevirtualizeMemberFunctionCalls(getContext(),
+ Base, MD);
+ const CXXRecordDecl *MostDerivedClassDecl =
+ Base->getMostDerivedClassDeclForType();
+
llvm::Value *Callee;
if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(MD)) {
if (UseVirtualCall) {
@@ -260,8 +240,13 @@
MD->isVirtual() &&
ME->hasQualifier())
Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty);
- else
- Callee = CGM.GetAddrOfFunction(GlobalDecl(Dtor, Dtor_Complete), Ty);
+ else {
+ const CXXMethodDecl *DM =
+ Dtor->getCorrespondingMethodInClass(MostDerivedClassDecl);
+ assert(DM);
+ const CXXDestructorDecl *DDtor = cast<CXXDestructorDecl>(DM);
+ Callee = CGM.GetAddrOfFunction(GlobalDecl(DDtor, Dtor_Complete), Ty);
+ }
}
} else if (const CXXConstructorDecl *Ctor =
dyn_cast<CXXConstructorDecl>(MD)) {
@@ -273,8 +258,12 @@
MD->isVirtual() &&
ME->hasQualifier())
Callee = BuildAppleKextVirtualCall(MD, ME->getQualifier(), Ty);
- else
- Callee = CGM.GetAddrOfFunction(MD, Ty);
+ else {
+ const CXXMethodDecl *DerivedMethod =
+ MD->getCorrespondingMethodInClass(MostDerivedClassDecl);
+ assert(DerivedMethod);
+ Callee = CGM.GetAddrOfFunction(DerivedMethod, Ty);
+ }
}
return EmitCXXMemberCall(MD, Callee, ReturnValue, This, /*VTT=*/0,
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 07f3c1d..4dd6f0b 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -10844,6 +10844,22 @@
}
SemaRef.MarkAnyDeclReferenced(Loc, D);
+
+ // If this is a call to a method via a cast, also mark the method in the
+ // derived class used in case codegen can devirtualize the call.
+ const MemberExpr *ME = dyn_cast<MemberExpr>(E);
+ if (!ME)
+ return;
+ CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ME->getMemberDecl());
+ if (!MD)
+ return;
+ const Expr *Base = ME->getBase();
+ const CXXRecordDecl *MostDerivedClassDecl
+ = Base->getMostDerivedClassDeclForType();
+ if (!MostDerivedClassDecl)
+ return;
+ CXXMethodDecl *DM = MD->getCorrespondingMethodInClass(MostDerivedClassDecl);
+ SemaRef.MarkAnyDeclReferenced(Loc, DM);
}
/// \brief Perform reference-marking and odr-use handling for a DeclRefExpr.
diff --git a/test/CodeGenCXX/devirtualize-virtual-function-calls-final.cpp b/test/CodeGenCXX/devirtualize-virtual-function-calls-final.cpp
index 3de75ed..f7b10f6 100644
--- a/test/CodeGenCXX/devirtualize-virtual-function-calls-final.cpp
+++ b/test/CodeGenCXX/devirtualize-virtual-function-calls-final.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -std=c++11 %s -emit-llvm -o - | FileCheck %s
namespace Test1 {
struct A {
@@ -49,3 +49,61 @@
return static_cast<B*>(v)->f();
}
}
+
+namespace Test4 {
+ struct A {
+ virtual void f();
+ };
+
+ struct B final : A {
+ virtual void f();
+ };
+
+ // CHECK: define void @_ZN5Test41fEPNS_1BE
+ void f(B* d) {
+ // CHECK: call void @_ZN5Test41B1fEv
+ static_cast<A*>(d)->f();
+ }
+}
+
+namespace Test5 {
+ struct A {
+ virtual void f();
+ };
+
+ struct B : A {
+ virtual void f();
+ };
+
+ struct C final : B {
+ };
+
+ // CHECK: define void @_ZN5Test51fEPNS_1CE
+ void f(C* d) {
+ // CHECK: call void @_ZN5Test51B1fEv
+ static_cast<A*>(d)->f();
+ }
+}
+
+namespace Test6 {
+ struct A {
+ virtual ~A();
+ };
+
+ struct B : public A {
+ virtual ~B();
+ };
+
+ struct C {
+ virtual ~C();
+ };
+
+ struct D final : public C, public B {
+ };
+
+ // CHECK: define void @_ZN5Test61fEPNS_1DE
+ void f(D* d) {
+ // CHECK: call void @_ZN5Test61DD1Ev
+ static_cast<A*>(d)->~A();
+ }
+}
