Fix inconsistent flag for disabling Dead Virtual Function Elimination

[ddcc]

ping

[tejohnson]

Can you add a test? You can probably just beef up clang/test/CodeGenCXX/virtual-function-elimination.cpp to test this option as well

[ddcc]

Add test

[tejohnson]

LGTM with the test change suggested below.

clang/test/CodeGenCXX/virtual-function-elimination.cpp

2

Since VFE isn't the default, I suspect you need to put -fvirtual-function-elimination before the -fno-virtual-function-elimination for it to really test that it is disabling VFE. (Although I realize that this does test this patch fix since presumably it complained about the unknown option before fixing it, but still it would be good to ensure that we're also testing that the -fno- form has the desired affect.)

[ddcc]

Update tests

[ddcc]

Hmm, looks like this was already fixed by e5158b52730d323bb8cd2cba6dc6c89b90cba452. I guess I'll just commit the test then?

[tejohnson]

LGTM for test - thanks! Yeah, it looks like that cleanup patch inadvertently fixed this issue as a side effect.

clang/test/CodeGenCXX/virtual-function-elimination.cpp

 // RUN: %clang_cc1 -triple x86_64-unknown-linux -flto -flto-unit -fvirtual-function-elimination -fwhole-program-vtables -emit-llvm -o - %s | FileCheck %s
-
+// RUN: %clang -target x86_64-unknown-linux -flto -fvirtual-function-elimination -fno-virtual-function-elimination -fwhole-program-vtables -S -emit-llvm -o - %s | FileCheck %s -check-prefix=NOVFE
 
 struct __attribute__((visibility("default"))) A {
   virtual void foo();
 };
 
 void test_1(A *p) {
   // A has default visibility, so no need for type.checked.load.
 // CHECK-LABEL: define void @_Z6test_1P1A
+// NOVFE-LABEL: define dso_local void @_Z6test_1P1A
 // CHECK: [[FN_PTR_ADDR:%.+]] = getelementptr inbounds void (%struct.A*)*, void (%struct.A*)** {{%.+}}, i64 0
+// NOVFE: [[FN_PTR_ADDR:%.+]] = getelementptr inbounds void (%struct.A*)*, void (%struct.A*)** {{%.+}}, i64 0
 // CHECK: [[FN_PTR:%.+]] = load void (%struct.A*)*, void (%struct.A*)** [[FN_PTR_ADDR]]
+// NOVFE: [[FN_PTR:%.+]] = load void (%struct.A*)*, void (%struct.A*)** [[FN_PTR_ADDR]]
 // CHECK: call void [[FN_PTR]](
+// NOVFE: call void [[FN_PTR]](
   p->foo();
 }
 
 
 struct __attribute__((visibility("hidden"))) [[clang::lto_visibility_public]] B {
   virtual void foo();
 };
 
 void test_2(B *p) {
   // B has public LTO visibility, so no need for type.checked.load.
 // CHECK-LABEL: define void @_Z6test_2P1B
+// NOVFE-LABEL: define dso_local void @_Z6test_2P1B
 // CHECK: [[FN_PTR_ADDR:%.+]] = getelementptr inbounds void (%struct.B*)*, void (%struct.B*)** {{%.+}}, i64 0
+// NOVFE: [[FN_PTR_ADDR:%.+]] = getelementptr inbounds void (%struct.B*)*, void (%struct.B*)** {{%.+}}, i64 0
 // CHECK: [[FN_PTR:%.+]] = load void (%struct.B*)*, void (%struct.B*)** [[FN_PTR_ADDR]]
+// NOVFE: [[FN_PTR:%.+]] = load void (%struct.B*)*, void (%struct.B*)** [[FN_PTR_ADDR]]
 // CHECK: call void [[FN_PTR]](
+// NOVFE: call void [[FN_PTR]](
   p->foo();
 }
 
 
 struct __attribute__((visibility("hidden"))) C {
   virtual void foo();
   virtual void bar();
 };
 
 void test_3(C *p) {
   // C has hidden visibility, so we generate type.checked.load to allow VFE.
 // CHECK-LABEL: define void @_Z6test_3P1C
+// NOVFE-LABEL: define dso_local void @_Z6test_3P1C
 // CHECK: [[LOAD:%.+]] = call { i8*, i1 } @llvm.type.checked.load(i8* {{%.+}}, i32 0, metadata !"_ZTS1C")
+// NOVFE: call i1 @llvm.type.test(i8* {{%.+}}, metadata !"_ZTS1C")
 // CHECK: [[FN_PTR_I8:%.+]] = extractvalue { i8*, i1 } [[LOAD]], 0
+// NOVFE: [[FN_PTR:%.+]] = load void (%struct.C*)*, void (%struct.C*)** {{%.+}}, align 8
 // CHECK: [[FN_PTR:%.+]] = bitcast i8* [[FN_PTR_I8]] to void (%struct.C*)*
 // CHECK: call void [[FN_PTR]](
+// NOVFE: call void [[FN_PTR]](
   p->foo();
 }
 
 void test_4(C *p) {
   // When using type.checked.load, we pass the vtable offset to the intrinsic,
   // rather than adding it to the pointer with a GEP.
 // CHECK-LABEL: define void @_Z6test_4P1C
+// NOVFE-LABEL: define dso_local void @_Z6test_4P1C
 // CHECK: [[LOAD:%.+]] = call { i8*, i1 } @llvm.type.checked.load(i8* {{%.+}}, i32 8, metadata !"_ZTS1C")
+// NOVFE: call i1 @llvm.type.test(i8* {{%.+}}, metadata !"_ZTS1C")
 // CHECK: [[FN_PTR_I8:%.+]] = extractvalue { i8*, i1 } [[LOAD]], 0
+// NOVFE: [[FN_PTR:%.+]] = load void (%struct.C*)*, void (%struct.C*)** {{%.+}}, align 8
 // CHECK: [[FN_PTR:%.+]] = bitcast i8* [[FN_PTR_I8]] to void (%struct.C*)*
 // CHECK: call void [[FN_PTR]](
+// NOVFE: call void [[FN_PTR]](
   p->bar();
 }
 
 void test_5(C *p, void (C::*q)(void)) {
   // We also use type.checked.load for the virtual side of member function
   // pointer calls. We use a GEP to calculate the address to load from and pass
   // 0 as the offset to the intrinsic, because we know that the load must be
   // from exactly the point marked by one of the function-type metadatas (in
   // this case "_ZTSM1CFvvE.virtual"). If we passed the offset from the member
   // function pointer to the intrinsic, this information would be lost. No
   // codegen changes on the non-virtual side.
 // CHECK-LABEL: define void @_Z6test_5P1CMS_FvvE(
+// NOVFE-LABEL: define dso_local void @_Z6test_5P1CMS_FvvE(
 // CHECK: [[FN_PTR_ADDR:%.+]] = getelementptr i8, i8* %vtable, i64 {{%.+}}
 // CHECK: [[LOAD:%.+]] = call { i8*, i1 } @llvm.type.checked.load(i8* [[FN_PTR_ADDR]], i32 0, metadata !"_ZTSM1CFvvE.virtual")
+// NOVFE-NOT: call { i8*, i1 } @llvm.type.checked.load(i8* {{%.+}}, i32 0, metadata !"_ZTSM1CFvvE.virtual")
 // CHECK: [[FN_PTR_I8:%.+]] = extractvalue { i8*, i1 } [[LOAD]], 0
 // CHECK: [[FN_PTR:%.+]] = bitcast i8* [[FN_PTR_I8]] to void (%struct.C*)*
+// NOVFE: [[FN_PTR:%.+]] = load void (%struct.C*)*, void (%struct.C*)** {{%.+}}, align 8
 
 // CHECK: [[PHI:%.+]] = phi void (%struct.C*)* {{.*}}[ [[FN_PTR]], {{.*}} ]
+// NOVFE: [[PHI:%.+]] = phi void (%struct.C*)* {{.*}}[ [[FN_PTR]], {{.*}} ]
 // CHECK: call void [[PHI]](
+// NOVFE: call void [[PHI]](
   (p->*q)();
 }