If a virtual member function has the 'final' attribute, we can devirtualize calls to it.
llvm-svn: 117444
diff --git a/clang/clang.xcodeproj/project.pbxproj b/clang/clang.xcodeproj/project.pbxproj
index 9c95d0a..fa1e245 100644
--- a/clang/clang.xcodeproj/project.pbxproj
+++ b/clang/clang.xcodeproj/project.pbxproj
@@ -2039,6 +2039,7 @@
isa = PBXProject;
buildConfigurationList = 1DEB923508733DC60010E9CD /* Build configuration list for PBXProject "clang" */;
compatibilityVersion = "Xcode 2.4";
+ developmentRegion = English;
hasScannedForEncodings = 1;
knownRegions = (
English,
diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 750e609..e3b5f71 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -55,7 +55,14 @@
/// canDevirtualizeMemberFunctionCalls - Checks whether virtual calls on given
/// expr can be devirtualized.
-static bool canDevirtualizeMemberFunctionCalls(const Expr *Base) {
+static bool canDevirtualizeMemberFunctionCalls(const Expr *Base,
+ const CXXMethodDecl *MD) {
+
+ // If the member function has the "final" attribute, we know that it can't be
+ // overridden and can therefor devirtualize it.
+ if (MD->hasAttr<FinalAttr>())
+ return true;
+
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.
@@ -76,7 +83,7 @@
// 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;
}
@@ -152,7 +159,7 @@
// 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 = MD->isVirtual() && !ME->hasQualifier()
- && !canDevirtualizeMemberFunctionCalls(ME->getBase());
+ && !canDevirtualizeMemberFunctionCalls(ME->getBase(), MD);
llvm::Value *Callee;
if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(MD)) {
@@ -267,7 +274,7 @@
This = LV.getAddress();
llvm::Value *Callee;
- if (MD->isVirtual() && !canDevirtualizeMemberFunctionCalls(E->getArg(0)))
+ if (MD->isVirtual() && !canDevirtualizeMemberFunctionCalls(E->getArg(0), MD))
Callee = BuildVirtualCall(MD, This, Ty);
else
Callee = CGM.GetAddrOfFunction(MD, Ty);
diff --git a/clang/test/CodeGenCXX/attr-final-devirtualize-virtual-function-calls.cpp b/clang/test/CodeGenCXX/attr-final-devirtualize-virtual-function-calls.cpp
new file mode 100644
index 0000000..b96cf04
--- /dev/null
+++ b/clang/test/CodeGenCXX/attr-final-devirtualize-virtual-function-calls.cpp
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 %s -O3 -emit-llvm -o - | FileCheck %s
+
+namespace Test1 {
+ struct A {
+ virtual int f() __attribute__((final)) { return 1; }
+ };
+
+ // CHECK: define i32 @_ZN5Test11fEPNS_1AE
+ int f(A* a) {
+ // CHECK: ret i32 1
+ return a->f();
+ }
+}